Background:Andrographis paniculata has been widely reported as an herbal plant for malaria treatment.The increasing rate of resistance to recommended antimalarial drugs has justified the need for a continuous search f...Background:Andrographis paniculata has been widely reported as an herbal plant for malaria treatment.The increasing rate of resistance to recommended antimalarial drugs has justified the need for a continuous search for new and more potent drugs that target all stages of the Plasmodium falciparum life cycle from natural plant sources.This study aimed to determine the antiplasmodial effect of phytocompounds derived from A.paniculata on the stages of plasmodium falciparum.Methods:Phytocompounds from A.paniculata were identified by Gas Chromatography-Mass Spectrophotometry(GCMS)analysis.The phytocompounds were screened for their druggability using Lipinski’s rule of five and subjected to Absorption,Distribution,Metabolism,Excretion,Toxicity(ADMET)and druglikeness analysis.The phytocompounds were docked against some validated drug targets at different stages of Plasmodium falciparum(hepatic,asexual,sexual,and vector targets)using PyRx software to analyze the inhibitory potential and protein-ligand interaction.Thereafter,the stability and flexibility of the best complexes were assessed through molecular dynamics simulations at 50ns using WebGRO.Result:The 7a-Isopropenyl-4,5-dimethyloctahydroinden-4-yl exhibited a higher binding affinity and better stability throughout the simulation period with P.falciparum dihydrofolate reductase-thymidylate synthase and Plasmodium falciparum M1 alanyl aminopeptidase for asexual blood stage and gametocyte stage of Plasmodium falciparum,respectively than the existing drugs.Meanwhile,N-Ethyl-3-methoxy-4-methylphenethylamine was also found to have a higher binding affinity and more stability throughout the simulation period with P.falciparum purine nucleoside phosphorylase and Plasmodium falciparum gametocyte surface protein for Hepatic schizonts stage of Plasmodium falciparum and gametocyte transmission blocking stage,respectively,than the existing drugs.Conclusion:The 7a-Isopropenyl-4,5-dimethyloctahydroinden-4-yl and N-Ethyl-3-methoxy-4 methylphenethylamine from A.paniculata are predicted as an antimalarial drug candidate.Thus,it is recommended that in vitro and in vivo bioassays be conducted on these hit compounds to validate these predictions.展开更多
Rationale: Malaria and dengue are the most prevalent vector-borne diseases in tropical countries. Plasmodium parasite and dengue virus(DENV) concurrent infection is possible and often under-recognized in geographical ...Rationale: Malaria and dengue are the most prevalent vector-borne diseases in tropical countries. Plasmodium parasite and dengue virus(DENV) concurrent infection is possible and often under-recognized in geographical areas where these infections are both endemic.Patients concern and diagnosis: We describe the first two cases of Plasmodium falciparum and DENV-3 co-infection in travelers returning to northeastern Italy from Burkina Faso during 2013-2014.Interventions: Malaria infection in both patients was treated with mefloquine. Due to the persistence of symptoms despite of the antimalaria treatment, dengue was also investigated;the treatment of dengue was symptomatic.Outcomes: The patients were discharged in good general condition.Lessons: The need for surveillance of potential malaria and dengue co-infection in travelers returning to Europe from endemic areas is highlighted, as infection with Plasmodium does not exclude arboviral co-infection.展开更多
Background: A marked decrease in malaria-related deaths worldwide has been attributed to the administration of effective antimalarials against Plasmodium falciparum. However, the continuous spread of P. falciparum res...Background: A marked decrease in malaria-related deaths worldwide has been attributed to the administration of effective antimalarials against Plasmodium falciparum. However, the continuous spread of P. falciparum resistance to anti-malarial drugs is raising a serious problem in controlling Malaria to the vulnerable children’s immune system. In recent studies, Plasmodium falciparum Kelch 13 propeller gene (Pfk13) has been reported to develop resistance to artemisinin in South Asia. In this study, we checked Plasmodium falciparum chloroquine resistance transporter gene (Pfcrt) involved in chloroquine (CQ) resistance. Method: In this study, archived 280 samples were collected from Alupe primary school children in Busia, Western Kenya from May, 2016 to November, 2016. Genomic DNA was extracted using the MightyPrep reagent. The samples were investigated for P. falciparum positivity out of which 67 of them tested positive giving a prevalence rate of 24%. The sixty-seven were subjected to PCR amplification for the molecular marker resistance to Pfcrt. After PCR amplification, the amplicons were purified and sequenced using Sanger Sequencing. The sequence data were analyzed using BioEdit software to identify point mutations. Results: 14 samples sequences were analyzed on Bioedit software giving the following amino acid changes F76C, Y66H, L70A, Y58C, T59V, V65I, P67L, T81L, Y60S, Y66S, P67T and I71F). New mutations have been reported at position 76 leading to an amino acid change, one of Pfcrt gold standard biomarkers. However, amino acid changes Y66H, L70A, Y58C, T59V, V65I, P67L, T81L, Y60S, Y66S, P67T and I71F are newly reported giving an increase in Pfcrt prevalence of concern from zero to 5.0%. A phylogenetic evolutionary relationship was constructed as shown below. Generally, the results showed a continuous resistance of P.falciparum to Pfcrt which calls for robust continuous monitoring and surveillance. Conclusion: Due to the increase of the resistant Pfcrt gene prevalence, continuous development of new mutants against chloroquine indicates that there is need to repurpose anti-malarial drugs for future partner drugs.展开更多
Objective:To assess the distribution of ABO blood group and their relationship with Plasmodium falciparum(P.falciparum) malaria among febrile outpatients who sought medical attention at Dore Bafeno Health Center,South...Objective:To assess the distribution of ABO blood group and their relationship with Plasmodium falciparum(P.falciparum) malaria among febrile outpatients who sought medical attention at Dore Bafeno Health Center,Southern Ethiopia.Methods:A total of 269 febrile outpatients who visited Dore Bafeno Health Center,Southern Ethiopia,were examined for malaria and also tested for ABO blood groups in January 2010.The blood specimens were collected by finger pricking,stained with Geimsa,and examined microscopically.Positive cases of the parasitemia were counted.CareStart^(TM) Malaria PflPv Combo was also used to test the blood specimens for malaria.ABO blood groups were determined by agglutination test using ERYCLONE antisera.Data on socio-demographic characteristics and treatment status of the participants were also collected.Chi-square and ANOVA tests were used to assess the difference between frequencies and means,respectively.Results:Out of a total of 269 participants,178(66.2%) febrile patients were found to be infected with Plasmodium parasites,among which 146(54.3%),28(10.4%),and 4(1.5%) belonged to P.falciparum,P.vivax,and mixed infections,respectively.All febrile patients were also tested for ABO blood groups and 51.3%,23.5%,21.9%and 3.3%were found to be blood types of 0,A,B and AB,respectively.Both total malaria infection and P.falciparum infection showed significant association with blood types(P<0.05).The proportion of A or B but not 0 phenotypes was higher(P<0.05) in individuals with P.falciparum as compared with non-infected individuals.The chance of having P.falciparum infection in patients with blood groups A,B and AB was 2.5,2.5 and 3.3times more than individuals showing blood 0 phenotypes,respectively.The mean P.falciparum malaria parasitemia for blood groups A,B,AB,and 0 were 3 744/μ L,1 805/ μ L,5 331/μ L,and1 515/μ L,respectively(P<0.01).Conclusions:The present findings indicate that individuals of blood groups A,B and AB are more susceptible to P.falciparum infection as compared with individuals of blood group O.Nevertheless,further in depth studies are required to clearly establish the role that ABO blood group plays in P.falciparum malaria.展开更多
Objective:To illustrate the clinical features and investigate the indicators associated with a fatal outcome in adult patients with severe Plasmodium falciparum malaria admitted to the Hospital for Tropical Diseases,B...Objective:To illustrate the clinical features and investigate the indicators associated with a fatal outcome in adult patients with severe Plasmodium falciparum malaria admitted to the Hospital for Tropical Diseases,Bangkok,Thailand.Methods:We studied 202 adult malaria patients admitted to the Intensive Care Unit.A total of 43 clinical variables were identified by univariate and logistic regression analyses,to eliminate confounding factors.Results:Regarding the statistical methods,only 6 variables-jaundice,cerebral malaria,metabolic acidosis,body mass index,initial respiratory rate,and white blood cell count-were significant indicators of death, with adjusted odds ratios(95%CI) of 15.2(2.1-32.3).4.3(2.3-12.6),3.3(2.3-5.7),2.4(1.9-3.5),2.2 (1.5-2.6),and 1.7(1.2-3.1),respectively.Conclusions:Our study found that jaundice,cerebral malaria,metabolic acidosis,body mass index,initial respiratory rate and white blood cell count were indicators of fatal outcome in severe Plasmodium falciparum malaria.Further studies on the fatal indicators in severe malaria need to be compared with data from different geographical areas,to construct practical measures to address potentially fatal indicators in different settings.展开更多
Objective:To analyse the structure and function of NADPH-cytochrome p450 reductase(CYPOR or CPR) from Plasmodium falciparum(Pf),and to predict its’ drug target and vaccine target. Methods:The structure,function,drug ...Objective:To analyse the structure and function of NADPH-cytochrome p450 reductase(CYPOR or CPR) from Plasmodium falciparum(Pf),and to predict its’ drug target and vaccine target. Methods:The structure,function,drug target and vaccine target of CPR from Plasmodium falciparum were analyzed and predicted by bioinformatics methods.Results:PfCPR,which was older CPR,had close relationship with the CPR from other Plasmodium species,but it was distant from its hosts,such as Homo sapiens and Anopheles.PfCPR was located in the cellular nucleus of Plasmodium falciparum.335aa-352aa and 591aa - 608aa were inserted the interior side of the nuclear membrane,while 151aa-265aa was located in the nucleolus organizer regions.PfCPR had 40 function sites and 44 protein-protein binding sites in amino acid sequence.The teriary structure of laa-700aa was forcep-shaped with wings.15 segments of PfCPR had no homology with Homo sapien CPR and most were exposed on the surface of the protein.These segments had 25 protein-protein binding sites.While 13 other segments all possessed function sites. Conclusions:The evolution or genesis of Plasmodium falciparum is earlier than those of Homo sapiens.PfCPR is a possible resistance site of antimalarial drug and may involve immune evasion, which is associated with parasite of sporozoite in hepatocytes.PfCPR is unsuitable as vaccine target,but it has at least 13 ideal drug targets.展开更多
Objective:To identify the possible antiplasmodial compounds from leaf,stem,root and flower extracts of Ocimum canum（O.canum）,Ocimum sanctum（O.sanctum） and Ocimum basilicum （O.basilicum）.Methods:The O.canum,O.san...Objective:To identify the possible antiplasmodial compounds from leaf,stem,root and flower extracts of Ocimum canum（O.canum）,Ocimum sanctum（O.sanctum） and Ocimum basilicum （O.basilicum）.Methods:The O.canum,O.sanctum and O.basilicum were collected from Ramanalhapuram District,Tamil Nadu and the extraction was carried out in ethanol.The filter sterilized extracts（100,30,23,12.5,6.23 and 3.125μg/mL） of leaf,stem,root and flower extracts of O.canum,O.sanctum and O.basilicum were tested for antiplasmodial activity against Plasmodium falciparum（P.falciparum）.The potential extracts were also tested for their phytochemical constituents.Results:The leaf extract of O.sanctum showed excellent antiplasmodial activity(IC<sub>50</sub> 3538μg/mL) followed by leaf extract of O.basilicum(IC<sub>50</sub> 4341μg/mL). The leaf extract of O.canum,root extracts of O.sanctum and O.basilicum,the stem and flower extracts of all the three tested Ocimum species showed IC<sub>50</sub> values between 50 and 100μg/mL Statistical analysis reveals that,significant antiplasmodial activity（P【0.01） was observed between the concentrations and time of exposure.The chemical injury to erythrocytes was also carried out and it shows that,there were no morphological changes in erythrocytes by the ethanolic extract of O.canum,O.sanctum and O.basilicum.The in vitro antiplasmodial activity might be due to the presence of alkaloids,glycosides,flavonoids,phenols,saponins,triterpenoids,proteins,resins, steroids and tannins in the ethanolic extracts of tested plants.Conclusions:The ethanolic leaf extracts of O.sanctum possess lead compounds for the development of antiplasmodial drugs.展开更多
Objective:Avidly phagocytosed hemozoin(malarial pigment) alters several functions of human monocytes and stimulates generation of several cytokines.Recently,we showed that phagocytosis of hemozoin by human monocytes i...Objective:Avidly phagocytosed hemozoin(malarial pigment) alters several functions of human monocytes and stimulates generation of several cytokines.Recently,we showed that phagocytosis of hemozoin by human monocytes increases expression and activity of matrix metalloproteinase-9,a proteolytic enzyme available in specific gelatinase granules,which contain several enzymes including lysozyme.Present work investigated active lysozyme release after phagocytosis of hemozoin and its dependence on production of tumor necrosis factor alpha. Methods:After phagocytosis of hemozoin,hemozoin-containing trophozoites or control meals(opsonized nonparasitized red blood cells and latex particles),monocyte supematants were monitored for 2 hours,in presence of blocking anti-human tumor necrosis factor alpha antibodies or recombinant human tumor necrosis factor alpha cytokine in selected experiments.Lysozyme release was evaluated by a specific spectrometric assay measuring lysozyme activity after coincubation of cell supematants with suspensions of Mycrococcus Lysodeikticus,while levels of soluble tumor necrosis factor alpha were analyzed by specific enzyme-linked immunodsorbent assay. Results:Levels of lysozyme activity and soluble tumor necrosis factor alpha protein were increased in hemozoin in-or trophozoites-laden monocytes supematants.Phagocytosis per se(control meals) also increased lysozyme release,but levels were significantly lower than those obtained after phagocytosis of hemozoin or trophozoites. Interestingly,all effects on lysozyme release observed after phagocytosis were abrogated by blocking anti-human tumor necrosis factor alpha antibodies,while they were mimicked by recombinant human tumor necrosis factor alpha cytokine.Conclusions:Present work shows that phagocytosis of hemozoin promotes monocyte degranulation and enhances active lysozyme release.The effect requires tumor necrosis factor alpha mediation.展开更多
Objective:To investigate the association between amplification of the two regulatory genes controlling glutathione(GSH) levels,glutathione reductase(PfGR) and glutathione S-transferase (PfGST) genes and sensitivity of...Objective:To investigate the association between amplification of the two regulatory genes controlling glutathione(GSH) levels,glutathione reductase(PfGR) and glutathione S-transferase (PfGST) genes and sensitivity of Plasmodium falciparum(P.falciparum) isolates collected from different malaria endemic areas of Thailand to standard antimalarial drugs.Methods:A total of 70 P.falciparum isolates were collected from endemic areas of multi-drug resistance (Tak,Chantaburi and Ranong Provinces) during the year 2008-2009.The in vitro assessment of antimalarial activity of P.falciparum clones(K1- and Dd2 chloroquine resistant and 3D7- chloroquine sensitive) and isolates to chloroquine,quinine,mefloquine and arteusnate was performed based on SYBR Green modified assay.Results:68(97.14%),11(15.71%) and 28(40%) isolates respectively were classified as chloroquine-,quinine- and mefloquine-resistant isolates. With this limited number of P.falciparum isolates included in the analysis,no significant association between amplification of PfGST gene and sensitivity of the parasite to chloroquine, quinine,mefloquine and quinine was found.Based on PCR analysis,Dd2,Kl and 3D7 clones all contained only one copy of the PfGST gene.All isolates(70) also carried only one copy number of PfGST gene.There appears to be an association between amplification of PfGR gene and chloroquine resistance.The 3D7 and Dd2 clones were found to carry only one PfGR gene copy, whereas the K1 clone carried two gene copies.Conclusions:Chloroquine resistance is likely to be a consequence of multi-factors and enzymes in the GSH system may be partly involved. Larger number of parasite isolates are required to increase power of the hypothesis testing in order to confirm the involvement of both genes as well as other genes implicated in glutathione metabolism in conferring chloroquine resistance.展开更多
Objective: To investigate in vitro antimalarial activity of chalcone derivative compounds against Plasmodum falciparum 3D7(Pf3D7) strain and in silico antimalarial activity.Methods: Synthesis of the chalcone derivativ...Objective: To investigate in vitro antimalarial activity of chalcone derivative compounds against Plasmodum falciparum 3D7(Pf3D7) strain and in silico antimalarial activity.Methods: Synthesis of the chalcone derivatives was conducted via Claisen-Schmidt method using NaOH 60% base as catalyst. An in vitro antimalarial activity assay was carried out according to the Rieckmann method against the chloroquine-sensitive Pf3D7 strain. Molecular docking studies of the prepared compounds were performed using Discovery Studio 3.1(Accelrys, Inc., San Diego, USA) software to dihydrofolate reductases-thymidylate synthase(PfDHFR-TS) protein with Protein Data Bank ID of 1J3I.pdb(sensitive-protein) and ID: 4DP3.pdb(resistance-protein).Results: This work has successfully synthesized seven chalcone derivatives with a great antimalarial activity. It has been revealed that allyloxy, hydroxy and alkoxy functional groups could increase the antimalarial activity of the chalcone derivatives. The best antimalarial activity of the prepared compounds was possessed by 3b with an IC_(50) value of 0.59 μM and categorized as an excellent antiplasmodial. Molecular docking studies of 3b showed binding interaction with the amino acid residues such as Ala16. Ile 164. Phe58.Tyr170 of the 1J3I.pdb protein and also Ala16, Phe58, Ile 112, Met55 of the 4DP3.pdb protein.Conclusions: An in vitro antimalarial assay of the prepared chalcone derivative(3a-g)showed an excellent and good antiplasmodial activity against the chloroquine-sensitive Pf3D7 strain. In silico antimalarial studies revealed that 3a-g made binding interaction with both sensitive-protein(IJ3I.pdb) and resistance-protein(4DP3.pdb), which means that they were both active against chloroquine-sensitive and resistant plasmodium strain.展开更多
Objective:To identify the possible anliplasmodial compounds from Achyranlhes aspera(A. aspera).Acalypha indica(A.indica),Jatropha glandulifera(J.glanduUfera)and Phyllanlhus amarus(P.amarus).Methods:The A.aspera,A.indi...Objective:To identify the possible anliplasmodial compounds from Achyranlhes aspera(A. aspera).Acalypha indica(A.indica),Jatropha glandulifera(J.glanduUfera)and Phyllanlhus amarus(P.amarus).Methods:The A.aspera,A.indica,J.glandulifera and P.ainarus were collected along Palk Strait and the extraction was carried out in ethanol.The filter sterilized extracts(100,50,25,12.5,6.25 and 3.125μg/mL) of leaf,stem,root and flower extracts of A aspera,A. indica,J.glandulifera and P.amarus were tested for anliplasmodial activity against Plasnuxlium falciparum.The potential extracts were also tested for their phytochemical constituents.Results: Of the selected plants species parts,the stem extract of A.indica showed excellent antiplasmodial activity(IC_(50)=43.81μg/mL) followed by stem extract of J.glandulifera(IC_(50)= 49.14μg/mL).The stem extract of A.aspera,leaf and root extracts of A.indka,leaf,root and seed extracts of J. glanduUfera and leaf and stem extracts of P.amarus showed IC_(50),values between 50 and 100 μg/ mL.Statistical analysis revealed that,significant antiplasmodial activity(P<0.0l) was observed between the concentrations and time of exposure.The chemical injury to erythrocytes was also carried out and it showed that there were no morphological changes in erythrocytes by the elhanolic extract of all the tested plant extracts.The in vitro antiplasmodial activity might be due to the presence of alkaloids,glycosides,flavonoids.phenols,saponins,triterpenoids,proteins, and lannins in the elhanolic extracts of tested plants.Conclusions:The elhanolic stem extracts of P.amarus and J.glandulifera possess lead compounds for the development of antiplasmodial drugs.展开更多
Objective:To examine array of some pro- and anti-inflammatory cytokines,namely, interleukin-4(IL-4),interleukin-10(IL-10),interferon-γ(IFN-γ),interleukin-5(IL-5), interleukin-6(IL-6),interleukin-12(IL-12) and tumor ...Objective:To examine array of some pro- and anti-inflammatory cytokines,namely, interleukin-4(IL-4),interleukin-10(IL-10),interferon-γ(IFN-γ),interleukin-5(IL-5), interleukin-6(IL-6),interleukin-12(IL-12) and tumor necrosis factor-α(TNF-α) concentrations in some Nigerians with falciparum malaria.Methods:Sera were obtained from the blood samples of 96 Nigerian children with Plasmodium falciparum infection.The sera were subjected to cytokine evaluation using commercial standard enzyme linked immunosorbent assay kits(Abcam,UK).Results:Mean pro-inflammatory cytokines in serum of children with uncomplicated and complicated malaria were IL-5 482.2 pg/mL versus 526.7 pg/mL,IL-6 98.8 pg/mL versus 82.6 pg/mL,IL-12 24.1 pg/mL versus 15.9 pg/mL,TNF-α107 pg/mL versus 511.7 pg/mL and IFN- 7 2.1 pg/mL versus 2.5 pg/mL.The anti-inflammatory cytokines status of IL-4 were 4.7 pg/mL versus 20.3 pg/mL,and IL-10 were 216 pg/mL versus 143.8 pg/mL in uncomplicated versus complicated/severe malaria cases.Participants with uncomplicated malaria had mean parasitaemia level of 3 158.9 parasites/μL while mean parasitaemia level for participants with complicated malaria was 12 550.5 parasite/μL and this difference was statistically significant(χ~2 =5 614.6,P【0.05).The difference between mean haemoglobin level for uncomplicated malaria(9.6 g/dL) and severe malaria(3.9 g/dL) was statistically significant (χ~2 = 2.3,P【0.05).The relationship between serum level of IL-6,IL-12,IFN-γ,IL-10 and IL-4 and ages showed positive correlation at r=0.92,0.99,0.86,0.95 and 0.85,respectively;while IL-5 and TNF-αhad negative correlation at r=-0.99 and -0.99,respectively.Conclusion: IL-4,IL-5,IL-6,IL-10,IL-12,TNF-αand IFN-γare involved in the immunopathology and immunoregulation of uncomplicated and complicated malaria infections.IL-6,IL-12,IFN-γand IL-10 depressed in complicated/severe malaria may not provide any protective immunity and may be indicators of poor prognosis in Plasmodium falciparum infected Nigerian children.展开更多
Objective:Malaria remains the single leading killer of children in sub - Sahara Africa and Schistosomiasis is considered to be second to malaria in global importance.Co - infection of malaria and urinary schistosomias...Objective:Malaria remains the single leading killer of children in sub - Sahara Africa and Schistosomiasis is considered to be second to malaria in global importance.Co - infection of malaria and urinary schistosomiasis has been reported to exacerbate disease morbidity such as anaemia.In different part of the globe,the co - infection between malaria and schistosomiasis provides some protections on the infected persons.The protective effect of this co - infection elucidated immunologically using cytokines is lacking in our locality.Methods:Urine and blood samples obtained from the 160 volunteers were subjected to standard parasitological techniques for diagnosis of urinary schistosomiasis and malaria respectively.Blood samples collected from these volunteers comprising 80 children with schistosomiasis and malaria and the 80 children who had malaria only were subjected to cytokines concentration determination using commercial standard enzyme linked immunosorbent assay kits(Abeam,UK).Results:Eighty participants with co - infection had a mean malarial parasitaemia of 662±201.1μL while the 80 participants with only P.falciparum malaria had a mean malarial parasiteamia of 5943±3270.7μL.Also the volunteers had mean haemoglobin of 11.2 g/dL for co - infected individuals and 5.7 g/dL for participants with single infection of malaria.The serum cytokine levels of the children with S. haematobium and P.falciparum and only P.falciparum infection are as follows;interleukin - 4(16.6 pg/ mL versus 5.2 pg/mL),IL - 5(501.3 pg/mL versus 357.5 pg/mL);IL -8(2 550 pg/mL versus 309 pg/mL),IL - 10(273 pg/mL versus 290 pg/mL),TNF -α(25 pg/mL versus 290 pg/mL) and IFN -γ(21.9 pg/mL versus 2.5 pg/mL).The TNF -α/IL - 10 ratio is 7 for the children with co - infection while those with only P.falciparum malaria infection had a TNF -α/IL - 10 ratio of 0.9.Conclusion:We conclude that the elevated IL - 4,IL - 5,IL - 8 and IFN -γconcentration induced by schistosomiasis altered the Th1/Th 2 profile and protected the children against the morbidity and severity of malaria attack among the children with co - infection.展开更多
Objective: To investigate the role of toll-like receptor 2(TLR2) in inflammatory activity of macrophage infected with the recombinant Mycobacterium bovis bacillus Calmette-Guerin(rBCG). Methods: Mouse macrophage cell ...Objective: To investigate the role of toll-like receptor 2(TLR2) in inflammatory activity of macrophage infected with the recombinant Mycobacterium bovis bacillus Calmette-Guerin(rBCG). Methods: Mouse macrophage cell line J774 A.1 was infected with Mycobacterium bovis bacillus Calmette-Guerin(BCG) and rBCG cultures for 48 h in the presence or absence of 10 μg/mL of TLR2 inhibitor. Untreated macrophages were used as a negative control while lipopolysaccharide-stimulated macrophages were used as a positive control. The ability of the macrophage to engulf the BCG and rBCG in the absence or presence of TLR2 inhibitor was assessed using a phagocytic assay, while the production of inflammatory cytokines and nitric oxide by the infected macrophages was evaluated using ELISA and Griess reagent method, while the expression of the inducible nitric oxide synthase was determined using Western blot analysis. Results: The results showed that blocking TLR2 function reduced the phagocytic activity, nitric oxide production and proinflammatory cytokine secretion such as TNF-α, IL-1β and IL-12 p40 as well as inducible nitric oxide synthase expression in the infected macrophages. These data showed the importance of TLR2 in the activation of macrophages following BCG and r BCG infections. Conclusions: Through exploring the immunological mechanism which underlies the protection conferred by the candidate vaccine, this study will improve our understanding of the vaccine candidate's mechanism to protect the host from malaria infection.展开更多
Objective:To investigate whether the increase of tumor necrosis factor alpha is dependent on lipidic component of malarial pigment.Methods:Adherent human monocytes were fed for 3 hours with different meals(native hemo...Objective:To investigate whether the increase of tumor necrosis factor alpha is dependent on lipidic component of malarial pigment.Methods:Adherent human monocytes were fed for 3 hours with different meals(native hemozoin;lipid free hemozoin;and control latex particles),then tumor necrosis factor alpha was monitored in cell supernatants up to 48 hours through western blotting or specific enzyme-linked immunoadsorbent assay.In selected experiments,unfed monocytes were treated with different doses of 15(S,R)-hydroxy-6,8,11,13-eicosatetraenoic acid or 4-hydroxynonenal instead of phagocytosis.Results:Hemozoin-fed monocytes produced higher levels of tumor necrosis factor alpha than unstimulated and latex-fed cells, while lipid-free hemozoin did not reproduce these results.Additionally,hemozoin effects were mimicked dose-dependently by 15(S,R)-hydroxy-6,8,11,13-eicosatetraenoic acid,but not by 4-hydroxynonenal.Conclusions:Present data suggest an essential role for lipids in hemozoindependent enhanced release of tumor necrosis factor alpha from monocytes,and 15(S,R)hydroxy -6,8,11,13-eicosatetraenoic acid could be one possible specific mediator.展开更多
A synthetic hybrid 45-peptide gene of Plasmodium falciparum (Pf), which encoded two CSP repeated peptides NANP and three merozoite peptides SPf83. 1, SPf55. 1 and SPf35. 1, was cloned in an expression vector pWR450-1,...A synthetic hybrid 45-peptide gene of Plasmodium falciparum (Pf), which encoded two CSP repeated peptides NANP and three merozoite peptides SPf83. 1, SPf55. 1 and SPf35. 1, was cloned in an expression vector pWR450-1, then the recombinant plasmid pWRA was introduced into the attenuated Salmonella typhimurium SL3261. When used as a live vaccine and administered orally (po), intravenously (iv) or intraperitoneally (ip),the recombinant strain was able to live in vivo and elicit specific humoral and cellular immunity in BALB/c mice and rabbits. As oral immunization is safe and effective, it is thought that the live recombinant Salmonella tyPhimurium vaccine may bring the Pf oral live vaccine a step nearer.展开更多
Objective: To explore whether its antiplasmodium effect of andrographolide is attributed to its plausible effect on the plasma membrane of both Plasmodium falciparum infected and noninfected RBCs. Methods: Anti-plasmo...Objective: To explore whether its antiplasmodium effect of andrographolide is attributed to its plausible effect on the plasma membrane of both Plasmodium falciparum infected and noninfected RBCs. Methods: Anti-plasmodium effect of andrographolide against Plasmodium falciparum strains was screened using the conventional malaria drug sensitivity assay. The drug was incubated with uninfected RBCs to monitor its effect on their morphology, integrity and osmotic fragility. It was incubated with the plasmodium infected RBCs to monitor its effect on the parasite induced permeation pathways. Its effect on the potential of merozoites to invade new RBCs was tested using merozoite invasion assay. Results: It showed that at andrographolide was innocuous to RBCs at concentrations approach its therapeutic level against plasmodia. Nevertheless, this inertness was dwindled at higher concentrations. Conclusions: In spite of its success to inhibit plasmodium induced permeation pathway and the potential of merozoites to invade new RBCs, its anti-plasmodium effect can't be attributed to these functions as they were attained at concentrations higher than what is required to eradicate the parasite. Consequently, other mechanisms may be associated with its claimed actions.展开更多
Objective To sequence the gene encoding glutamate rich protein (GLURP) andidentify the genotypes of geographically different Plasmodium falciparum (P. f ) isolatesfrom China. Methods The gene of R2 repeat region of GL...Objective To sequence the gene encoding glutamate rich protein (GLURP) andidentify the genotypes of geographically different Plasmodium falciparum (P. f ) isolatesfrom China. Methods The gene of R2 repeat region of GLURP was amplified by nestedpolymerase chain reaction and cloned into T-vector. The nucleotide sequence of GLURPgene was determined by automatic sequencer (Dideoxy termination method) and analyzed byDNA Star software. Results At least 7 different GLURP genotypes ranging from 600 bpto 1 500 bp were found in Yunnan and Hainan provinces. R2 region of GLURP gene consistedof several repeat units. Each repeat unit was composed of 19-20 residues which were shownto be highly conserved. GLURP gene was also size polymorphic due to differences in thenumber of repeat units, whereas the repeat sequence was conserved. Sequence analysisshowed that DNA sequences and deduced amino acid sequences were highly homologousamong the geographically dispersed isolates or various isolates from the same geographicalregion. No obvious differences were found in the GLURP gene sequences amonggeographically different isolates. Conclusion GLURP gene is highly structure conservedand size polymorphic, and so is useful in searching for malaria vaccine candidate antigen anddeveloping a genotyping method for malaria research.展开更多
Objective:To investigate the distribution and patterns of pfcrt and pfmdr1 polymorphisms in Plasmodium falciparum(P.falciparum)isolates collected from the malaria endemic area of Thailand along Thai-Myanmar border.Met...Objective:To investigate the distribution and patterns of pfcrt and pfmdr1 polymorphisms in Plasmodium falciparum(P.falciparum)isolates collected from the malaria endemic area of Thailand along Thai-Myanmar border.Methods:Dried blood spot samples were collected from 172 falciparum malaria patients prior received treatment.The samples were extracted using chelex to obtain parasite DNA.PCR-RFLP was employed to detect pfert mutation at codons 76,220,271,326,3S6 and 371,and the pfmdr1mutation at codon 86.Pfmdr1 gene copy number was determined by SYBR Green 1 real-time PCR.Results:Mutant alleles of pfcrt and wild type allele of pfmdrl were found in almost all samples.Pfmdrl gene copy number in isolates collected from all areas ranged from 1.0 to S.0 copies and proportion of isolates carrying>1 gene copies was 38.1%.The distribution and patterns of pfcrt and pfmdrl mutations were similar in P.falciparum isolates from all areas.However,significant differences in both number of gfmdr1 copies and prevalence of isolates carrying>1 gene copies were observed among isolates collected from different areas.The median pfmdr1 copy number in P.falciparum collected from Kanchanaburi and Mae Hongson were 2.5 and 2.0,respectively and more than half of the isolates carried>1 gene copies.Conclusions:The observation of pfindr1 wild type and increasing of gene copy number may suggest declining of artesunate-mefloquine treatment efficacy in P.falciparum isolates in this border area.展开更多
Objective:To study the genetic diversity at the msp—1,msp—2,and glurp genes of Plasmodium falciparum(P.falciparum) isolates from 3 endemic areas in Thailand:Tak.Kanchanaburi and Ranong provinces.Methods:A total of 1...Objective:To study the genetic diversity at the msp—1,msp—2,and glurp genes of Plasmodium falciparum(P.falciparum) isolates from 3 endemic areas in Thailand:Tak.Kanchanaburi and Ranong provinces.Methods:A total of 144 P.falciparum isolates collected prior to Irealmenl during January.2012 to June,2013 were genotyped.DNA was extracted:allele frequency and diversity of msp-1.msp-2,and glurp genes were investigated by nested polymerase chain reaction.Results:P.falciparum isolates in this study had high rate of multiple genotypes infection(96.5%)with an overall mean multiplicity of infection of 3.21.The distribution of allelic families of msp-1was significantly different among isolales from Tak.kanchanahnri.and Ranong but not for the msp-2.K1 and MAD20 were the predominant allelic families at the msp-1 gene,whereas alleles belonging to 3D7 were more frequent at the msp-2 gene.The glurp gene had the least diverse alleles.Population structure of P.falciparum isolates from Tak and Ranong was quite similar as revealed by the presence of similar proportions of MAD20 and K1 alleles at msp-1 loci.3D7 and FC27 alleles at msp-2 loci as well as comparable mean MOI.Isolates from Kanchanaburi had different structures;the most prevalent alleles were K1 and RO33.Conclusions:The present study shows that P.falciparum isolates from Tak and Ranong provinces had similar allelic pattern of msp—1 and msp—2 and diversity but different from Kanchanaburi isolates.These allelic variant profiles are valuable baseline data for future epidemiological study of malaria transmission and for continued monitoring of polymorphisms associated with antimalarial drug resistance in these areas.展开更多
文摘Background:Andrographis paniculata has been widely reported as an herbal plant for malaria treatment.The increasing rate of resistance to recommended antimalarial drugs has justified the need for a continuous search for new and more potent drugs that target all stages of the Plasmodium falciparum life cycle from natural plant sources.This study aimed to determine the antiplasmodial effect of phytocompounds derived from A.paniculata on the stages of plasmodium falciparum.Methods:Phytocompounds from A.paniculata were identified by Gas Chromatography-Mass Spectrophotometry(GCMS)analysis.The phytocompounds were screened for their druggability using Lipinski’s rule of five and subjected to Absorption,Distribution,Metabolism,Excretion,Toxicity(ADMET)and druglikeness analysis.The phytocompounds were docked against some validated drug targets at different stages of Plasmodium falciparum(hepatic,asexual,sexual,and vector targets)using PyRx software to analyze the inhibitory potential and protein-ligand interaction.Thereafter,the stability and flexibility of the best complexes were assessed through molecular dynamics simulations at 50ns using WebGRO.Result:The 7a-Isopropenyl-4,5-dimethyloctahydroinden-4-yl exhibited a higher binding affinity and better stability throughout the simulation period with P.falciparum dihydrofolate reductase-thymidylate synthase and Plasmodium falciparum M1 alanyl aminopeptidase for asexual blood stage and gametocyte stage of Plasmodium falciparum,respectively than the existing drugs.Meanwhile,N-Ethyl-3-methoxy-4-methylphenethylamine was also found to have a higher binding affinity and more stability throughout the simulation period with P.falciparum purine nucleoside phosphorylase and Plasmodium falciparum gametocyte surface protein for Hepatic schizonts stage of Plasmodium falciparum and gametocyte transmission blocking stage,respectively,than the existing drugs.Conclusion:The 7a-Isopropenyl-4,5-dimethyloctahydroinden-4-yl and N-Ethyl-3-methoxy-4 methylphenethylamine from A.paniculata are predicted as an antimalarial drug candidate.Thus,it is recommended that in vitro and in vivo bioassays be conducted on these hit compounds to validate these predictions.
文摘Rationale: Malaria and dengue are the most prevalent vector-borne diseases in tropical countries. Plasmodium parasite and dengue virus(DENV) concurrent infection is possible and often under-recognized in geographical areas where these infections are both endemic.Patients concern and diagnosis: We describe the first two cases of Plasmodium falciparum and DENV-3 co-infection in travelers returning to northeastern Italy from Burkina Faso during 2013-2014.Interventions: Malaria infection in both patients was treated with mefloquine. Due to the persistence of symptoms despite of the antimalaria treatment, dengue was also investigated;the treatment of dengue was symptomatic.Outcomes: The patients were discharged in good general condition.Lessons: The need for surveillance of potential malaria and dengue co-infection in travelers returning to Europe from endemic areas is highlighted, as infection with Plasmodium does not exclude arboviral co-infection.
文摘Background: A marked decrease in malaria-related deaths worldwide has been attributed to the administration of effective antimalarials against Plasmodium falciparum. However, the continuous spread of P. falciparum resistance to anti-malarial drugs is raising a serious problem in controlling Malaria to the vulnerable children’s immune system. In recent studies, Plasmodium falciparum Kelch 13 propeller gene (Pfk13) has been reported to develop resistance to artemisinin in South Asia. In this study, we checked Plasmodium falciparum chloroquine resistance transporter gene (Pfcrt) involved in chloroquine (CQ) resistance. Method: In this study, archived 280 samples were collected from Alupe primary school children in Busia, Western Kenya from May, 2016 to November, 2016. Genomic DNA was extracted using the MightyPrep reagent. The samples were investigated for P. falciparum positivity out of which 67 of them tested positive giving a prevalence rate of 24%. The sixty-seven were subjected to PCR amplification for the molecular marker resistance to Pfcrt. After PCR amplification, the amplicons were purified and sequenced using Sanger Sequencing. The sequence data were analyzed using BioEdit software to identify point mutations. Results: 14 samples sequences were analyzed on Bioedit software giving the following amino acid changes F76C, Y66H, L70A, Y58C, T59V, V65I, P67L, T81L, Y60S, Y66S, P67T and I71F). New mutations have been reported at position 76 leading to an amino acid change, one of Pfcrt gold standard biomarkers. However, amino acid changes Y66H, L70A, Y58C, T59V, V65I, P67L, T81L, Y60S, Y66S, P67T and I71F are newly reported giving an increase in Pfcrt prevalence of concern from zero to 5.0%. A phylogenetic evolutionary relationship was constructed as shown below. Generally, the results showed a continuous resistance of P.falciparum to Pfcrt which calls for robust continuous monitoring and surveillance. Conclusion: Due to the increase of the resistant Pfcrt gene prevalence, continuous development of new mutants against chloroquine indicates that there is need to repurpose anti-malarial drugs for future partner drugs.
基金Supported by School of Graduate Studies through Aklilu LemmaInstitute of Pathobiology,Addis Ababa University(No:RDP/Py-014/09)
文摘Objective:To assess the distribution of ABO blood group and their relationship with Plasmodium falciparum(P.falciparum) malaria among febrile outpatients who sought medical attention at Dore Bafeno Health Center,Southern Ethiopia.Methods:A total of 269 febrile outpatients who visited Dore Bafeno Health Center,Southern Ethiopia,were examined for malaria and also tested for ABO blood groups in January 2010.The blood specimens were collected by finger pricking,stained with Geimsa,and examined microscopically.Positive cases of the parasitemia were counted.CareStart^(TM) Malaria PflPv Combo was also used to test the blood specimens for malaria.ABO blood groups were determined by agglutination test using ERYCLONE antisera.Data on socio-demographic characteristics and treatment status of the participants were also collected.Chi-square and ANOVA tests were used to assess the difference between frequencies and means,respectively.Results:Out of a total of 269 participants,178(66.2%) febrile patients were found to be infected with Plasmodium parasites,among which 146(54.3%),28(10.4%),and 4(1.5%) belonged to P.falciparum,P.vivax,and mixed infections,respectively.All febrile patients were also tested for ABO blood groups and 51.3%,23.5%,21.9%and 3.3%were found to be blood types of 0,A,B and AB,respectively.Both total malaria infection and P.falciparum infection showed significant association with blood types(P<0.05).The proportion of A or B but not 0 phenotypes was higher(P<0.05) in individuals with P.falciparum as compared with non-infected individuals.The chance of having P.falciparum infection in patients with blood groups A,B and AB was 2.5,2.5 and 3.3times more than individuals showing blood 0 phenotypes,respectively.The mean P.falciparum malaria parasitemia for blood groups A,B,AB,and 0 were 3 744/μ L,1 805/ μ L,5 331/μ L,and1 515/μ L,respectively(P<0.01).Conclusions:The present findings indicate that individuals of blood groups A,B and AB are more susceptible to P.falciparum infection as compared with individuals of blood group O.Nevertheless,further in depth studies are required to clearly establish the role that ABO blood group plays in P.falciparum malaria.
文摘Objective:To illustrate the clinical features and investigate the indicators associated with a fatal outcome in adult patients with severe Plasmodium falciparum malaria admitted to the Hospital for Tropical Diseases,Bangkok,Thailand.Methods:We studied 202 adult malaria patients admitted to the Intensive Care Unit.A total of 43 clinical variables were identified by univariate and logistic regression analyses,to eliminate confounding factors.Results:Regarding the statistical methods,only 6 variables-jaundice,cerebral malaria,metabolic acidosis,body mass index,initial respiratory rate,and white blood cell count-were significant indicators of death, with adjusted odds ratios(95%CI) of 15.2(2.1-32.3).4.3(2.3-12.6),3.3(2.3-5.7),2.4(1.9-3.5),2.2 (1.5-2.6),and 1.7(1.2-3.1),respectively.Conclusions:Our study found that jaundice,cerebral malaria,metabolic acidosis,body mass index,initial respiratory rate and white blood cell count were indicators of fatal outcome in severe Plasmodium falciparum malaria.Further studies on the fatal indicators in severe malaria need to be compared with data from different geographical areas,to construct practical measures to address potentially fatal indicators in different settings.
基金Supported in part by the Research Program in Higher Educational Institutes of Education Department in Hainan(No.Hjkj2009-50)
文摘Objective:To analyse the structure and function of NADPH-cytochrome p450 reductase(CYPOR or CPR) from Plasmodium falciparum(Pf),and to predict its’ drug target and vaccine target. Methods:The structure,function,drug target and vaccine target of CPR from Plasmodium falciparum were analyzed and predicted by bioinformatics methods.Results:PfCPR,which was older CPR,had close relationship with the CPR from other Plasmodium species,but it was distant from its hosts,such as Homo sapiens and Anopheles.PfCPR was located in the cellular nucleus of Plasmodium falciparum.335aa-352aa and 591aa - 608aa were inserted the interior side of the nuclear membrane,while 151aa-265aa was located in the nucleolus organizer regions.PfCPR had 40 function sites and 44 protein-protein binding sites in amino acid sequence.The teriary structure of laa-700aa was forcep-shaped with wings.15 segments of PfCPR had no homology with Homo sapien CPR and most were exposed on the surface of the protein.These segments had 25 protein-protein binding sites.While 13 other segments all possessed function sites. Conclusions:The evolution or genesis of Plasmodium falciparum is earlier than those of Homo sapiens.PfCPR is a possible resistance site of antimalarial drug and may involve immune evasion, which is associated with parasite of sporozoite in hepatocytes.PfCPR is unsuitable as vaccine target,but it has at least 13 ideal drug targets.
基金financially supported by Indian Council of Medical Research.New Delhi.The funding agency grant number is 59/6/2002/BMS/TRM
文摘Objective:To identify the possible antiplasmodial compounds from leaf,stem,root and flower extracts of Ocimum canum（O.canum）,Ocimum sanctum（O.sanctum） and Ocimum basilicum （O.basilicum）.Methods:The O.canum,O.sanctum and O.basilicum were collected from Ramanalhapuram District,Tamil Nadu and the extraction was carried out in ethanol.The filter sterilized extracts（100,30,23,12.5,6.23 and 3.125μg/mL） of leaf,stem,root and flower extracts of O.canum,O.sanctum and O.basilicum were tested for antiplasmodial activity against Plasmodium falciparum（P.falciparum）.The potential extracts were also tested for their phytochemical constituents.Results:The leaf extract of O.sanctum showed excellent antiplasmodial activity(IC<sub>50</sub> 3538μg/mL) followed by leaf extract of O.basilicum(IC<sub>50</sub> 4341μg/mL). The leaf extract of O.canum,root extracts of O.sanctum and O.basilicum,the stem and flower extracts of all the three tested Ocimum species showed IC<sub>50</sub> values between 50 and 100μg/mL Statistical analysis reveals that,significant antiplasmodial activity（P【0.01） was observed between the concentrations and time of exposure.The chemical injury to erythrocytes was also carried out and it shows that,there were no morphological changes in erythrocytes by the ethanolic extract of O.canum,O.sanctum and O.basilicum.The in vitro antiplasmodial activity might be due to the presence of alkaloids,glycosides,flavonoids,phenols,saponins,triterpenoids,proteins,resins, steroids and tannins in the ethanolic extracts of tested plants.Conclusions:The ethanolic leaf extracts of O.sanctum possess lead compounds for the development of antiplasmodial drugs.
基金supported in the context of the Italian Malaria Network by grants from Compagnia di San Paolo-IMIthe University of Torino Intramural FundsRegione Piemonte,Ricerca Sanitaria Finalizzata 2007 to PA
文摘Objective:Avidly phagocytosed hemozoin(malarial pigment) alters several functions of human monocytes and stimulates generation of several cytokines.Recently,we showed that phagocytosis of hemozoin by human monocytes increases expression and activity of matrix metalloproteinase-9,a proteolytic enzyme available in specific gelatinase granules,which contain several enzymes including lysozyme.Present work investigated active lysozyme release after phagocytosis of hemozoin and its dependence on production of tumor necrosis factor alpha. Methods:After phagocytosis of hemozoin,hemozoin-containing trophozoites or control meals(opsonized nonparasitized red blood cells and latex particles),monocyte supematants were monitored for 2 hours,in presence of blocking anti-human tumor necrosis factor alpha antibodies or recombinant human tumor necrosis factor alpha cytokine in selected experiments.Lysozyme release was evaluated by a specific spectrometric assay measuring lysozyme activity after coincubation of cell supematants with suspensions of Mycrococcus Lysodeikticus,while levels of soluble tumor necrosis factor alpha were analyzed by specific enzyme-linked immunodsorbent assay. Results:Levels of lysozyme activity and soluble tumor necrosis factor alpha protein were increased in hemozoin in-or trophozoites-laden monocytes supematants.Phagocytosis per se(control meals) also increased lysozyme release,but levels were significantly lower than those obtained after phagocytosis of hemozoin or trophozoites. Interestingly,all effects on lysozyme release observed after phagocytosis were abrogated by blocking anti-human tumor necrosis factor alpha antibodies,while they were mimicked by recombinant human tumor necrosis factor alpha cytokine.Conclusions:Present work shows that phagocytosis of hemozoin promotes monocyte degranulation and enhances active lysozyme release.The effect requires tumor necrosis factor alpha mediation.
基金supported by Thammasat University and The Commission on Higher Education,Ministry of Education of Thailand
文摘Objective:To investigate the association between amplification of the two regulatory genes controlling glutathione(GSH) levels,glutathione reductase(PfGR) and glutathione S-transferase (PfGST) genes and sensitivity of Plasmodium falciparum(P.falciparum) isolates collected from different malaria endemic areas of Thailand to standard antimalarial drugs.Methods:A total of 70 P.falciparum isolates were collected from endemic areas of multi-drug resistance (Tak,Chantaburi and Ranong Provinces) during the year 2008-2009.The in vitro assessment of antimalarial activity of P.falciparum clones(K1- and Dd2 chloroquine resistant and 3D7- chloroquine sensitive) and isolates to chloroquine,quinine,mefloquine and arteusnate was performed based on SYBR Green modified assay.Results:68(97.14%),11(15.71%) and 28(40%) isolates respectively were classified as chloroquine-,quinine- and mefloquine-resistant isolates. With this limited number of P.falciparum isolates included in the analysis,no significant association between amplification of PfGST gene and sensitivity of the parasite to chloroquine, quinine,mefloquine and quinine was found.Based on PCR analysis,Dd2,Kl and 3D7 clones all contained only one copy of the PfGST gene.All isolates(70) also carried only one copy number of PfGST gene.There appears to be an association between amplification of PfGR gene and chloroquine resistance.The 3D7 and Dd2 clones were found to carry only one PfGR gene copy, whereas the K1 clone carried two gene copies.Conclusions:Chloroquine resistance is likely to be a consequence of multi-factors and enzymes in the GSH system may be partly involved. Larger number of parasite isolates are required to increase power of the hypothesis testing in order to confirm the involvement of both genes as well as other genes implicated in glutathione metabolism in conferring chloroquine resistance.
基金Ministry of Research,Technology,and Higher Education-Indonesia for the financial support of this work through Hibah Penelitian Disertasi Doktor (PDD)T.A 2017
文摘Objective: To investigate in vitro antimalarial activity of chalcone derivative compounds against Plasmodum falciparum 3D7(Pf3D7) strain and in silico antimalarial activity.Methods: Synthesis of the chalcone derivatives was conducted via Claisen-Schmidt method using NaOH 60% base as catalyst. An in vitro antimalarial activity assay was carried out according to the Rieckmann method against the chloroquine-sensitive Pf3D7 strain. Molecular docking studies of the prepared compounds were performed using Discovery Studio 3.1(Accelrys, Inc., San Diego, USA) software to dihydrofolate reductases-thymidylate synthase(PfDHFR-TS) protein with Protein Data Bank ID of 1J3I.pdb(sensitive-protein) and ID: 4DP3.pdb(resistance-protein).Results: This work has successfully synthesized seven chalcone derivatives with a great antimalarial activity. It has been revealed that allyloxy, hydroxy and alkoxy functional groups could increase the antimalarial activity of the chalcone derivatives. The best antimalarial activity of the prepared compounds was possessed by 3b with an IC_(50) value of 0.59 μM and categorized as an excellent antiplasmodial. Molecular docking studies of 3b showed binding interaction with the amino acid residues such as Ala16. Ile 164. Phe58.Tyr170 of the 1J3I.pdb protein and also Ala16, Phe58, Ile 112, Met55 of the 4DP3.pdb protein.Conclusions: An in vitro antimalarial assay of the prepared chalcone derivative(3a-g)showed an excellent and good antiplasmodial activity against the chloroquine-sensitive Pf3D7 strain. In silico antimalarial studies revealed that 3a-g made binding interaction with both sensitive-protein(IJ3I.pdb) and resistance-protein(4DP3.pdb), which means that they were both active against chloroquine-sensitive and resistant plasmodium strain.
基金Supported by Indian Council of Medical Research,New Delhi(No.59/6/2002/BMS/TRM)
文摘Objective:To identify the possible anliplasmodial compounds from Achyranlhes aspera(A. aspera).Acalypha indica(A.indica),Jatropha glandulifera(J.glanduUfera)and Phyllanlhus amarus(P.amarus).Methods:The A.aspera,A.indica,J.glandulifera and P.ainarus were collected along Palk Strait and the extraction was carried out in ethanol.The filter sterilized extracts(100,50,25,12.5,6.25 and 3.125μg/mL) of leaf,stem,root and flower extracts of A aspera,A. indica,J.glandulifera and P.amarus were tested for anliplasmodial activity against Plasnuxlium falciparum.The potential extracts were also tested for their phytochemical constituents.Results: Of the selected plants species parts,the stem extract of A.indica showed excellent antiplasmodial activity(IC_(50)=43.81μg/mL) followed by stem extract of J.glandulifera(IC_(50)= 49.14μg/mL).The stem extract of A.aspera,leaf and root extracts of A.indka,leaf,root and seed extracts of J. glanduUfera and leaf and stem extracts of P.amarus showed IC_(50),values between 50 and 100 μg/ mL.Statistical analysis revealed that,significant antiplasmodial activity(P<0.0l) was observed between the concentrations and time of exposure.The chemical injury to erythrocytes was also carried out and it showed that there were no morphological changes in erythrocytes by the elhanolic extract of all the tested plant extracts.The in vitro antiplasmodial activity might be due to the presence of alkaloids,glycosides,flavonoids.phenols,saponins,triterpenoids,proteins, and lannins in the elhanolic extracts of tested plants.Conclusions:The elhanolic stem extracts of P.amarus and J.glandulifera possess lead compounds for the development of antiplasmodial drugs.
文摘Objective:To examine array of some pro- and anti-inflammatory cytokines,namely, interleukin-4(IL-4),interleukin-10(IL-10),interferon-γ(IFN-γ),interleukin-5(IL-5), interleukin-6(IL-6),interleukin-12(IL-12) and tumor necrosis factor-α(TNF-α) concentrations in some Nigerians with falciparum malaria.Methods:Sera were obtained from the blood samples of 96 Nigerian children with Plasmodium falciparum infection.The sera were subjected to cytokine evaluation using commercial standard enzyme linked immunosorbent assay kits(Abcam,UK).Results:Mean pro-inflammatory cytokines in serum of children with uncomplicated and complicated malaria were IL-5 482.2 pg/mL versus 526.7 pg/mL,IL-6 98.8 pg/mL versus 82.6 pg/mL,IL-12 24.1 pg/mL versus 15.9 pg/mL,TNF-α107 pg/mL versus 511.7 pg/mL and IFN- 7 2.1 pg/mL versus 2.5 pg/mL.The anti-inflammatory cytokines status of IL-4 were 4.7 pg/mL versus 20.3 pg/mL,and IL-10 were 216 pg/mL versus 143.8 pg/mL in uncomplicated versus complicated/severe malaria cases.Participants with uncomplicated malaria had mean parasitaemia level of 3 158.9 parasites/μL while mean parasitaemia level for participants with complicated malaria was 12 550.5 parasite/μL and this difference was statistically significant(χ~2 =5 614.6,P【0.05).The difference between mean haemoglobin level for uncomplicated malaria(9.6 g/dL) and severe malaria(3.9 g/dL) was statistically significant (χ~2 = 2.3,P【0.05).The relationship between serum level of IL-6,IL-12,IFN-γ,IL-10 and IL-4 and ages showed positive correlation at r=0.92,0.99,0.86,0.95 and 0.85,respectively;while IL-5 and TNF-αhad negative correlation at r=-0.99 and -0.99,respectively.Conclusion: IL-4,IL-5,IL-6,IL-10,IL-12,TNF-αand IFN-γare involved in the immunopathology and immunoregulation of uncomplicated and complicated malaria infections.IL-6,IL-12,IFN-γand IL-10 depressed in complicated/severe malaria may not provide any protective immunity and may be indicators of poor prognosis in Plasmodium falciparum infected Nigerian children.
文摘Objective:Malaria remains the single leading killer of children in sub - Sahara Africa and Schistosomiasis is considered to be second to malaria in global importance.Co - infection of malaria and urinary schistosomiasis has been reported to exacerbate disease morbidity such as anaemia.In different part of the globe,the co - infection between malaria and schistosomiasis provides some protections on the infected persons.The protective effect of this co - infection elucidated immunologically using cytokines is lacking in our locality.Methods:Urine and blood samples obtained from the 160 volunteers were subjected to standard parasitological techniques for diagnosis of urinary schistosomiasis and malaria respectively.Blood samples collected from these volunteers comprising 80 children with schistosomiasis and malaria and the 80 children who had malaria only were subjected to cytokines concentration determination using commercial standard enzyme linked immunosorbent assay kits(Abeam,UK).Results:Eighty participants with co - infection had a mean malarial parasitaemia of 662±201.1μL while the 80 participants with only P.falciparum malaria had a mean malarial parasiteamia of 5943±3270.7μL.Also the volunteers had mean haemoglobin of 11.2 g/dL for co - infected individuals and 5.7 g/dL for participants with single infection of malaria.The serum cytokine levels of the children with S. haematobium and P.falciparum and only P.falciparum infection are as follows;interleukin - 4(16.6 pg/ mL versus 5.2 pg/mL),IL - 5(501.3 pg/mL versus 357.5 pg/mL);IL -8(2 550 pg/mL versus 309 pg/mL),IL - 10(273 pg/mL versus 290 pg/mL),TNF -α(25 pg/mL versus 290 pg/mL) and IFN -γ(21.9 pg/mL versus 2.5 pg/mL).The TNF -α/IL - 10 ratio is 7 for the children with co - infection while those with only P.falciparum malaria infection had a TNF -α/IL - 10 ratio of 0.9.Conclusion:We conclude that the elevated IL - 4,IL - 5,IL - 8 and IFN -γconcentration induced by schistosomiasis altered the Th1/Th 2 profile and protected the children against the morbidity and severity of malaria attack among the children with co - infection.
基金supported by the Universiti Sains Malaysia Fundamental Research Grant Scheme(No.203/PPSK/6171158)
文摘Objective: To investigate the role of toll-like receptor 2(TLR2) in inflammatory activity of macrophage infected with the recombinant Mycobacterium bovis bacillus Calmette-Guerin(rBCG). Methods: Mouse macrophage cell line J774 A.1 was infected with Mycobacterium bovis bacillus Calmette-Guerin(BCG) and rBCG cultures for 48 h in the presence or absence of 10 μg/mL of TLR2 inhibitor. Untreated macrophages were used as a negative control while lipopolysaccharide-stimulated macrophages were used as a positive control. The ability of the macrophage to engulf the BCG and rBCG in the absence or presence of TLR2 inhibitor was assessed using a phagocytic assay, while the production of inflammatory cytokines and nitric oxide by the infected macrophages was evaluated using ELISA and Griess reagent method, while the expression of the inducible nitric oxide synthase was determined using Western blot analysis. Results: The results showed that blocking TLR2 function reduced the phagocytic activity, nitric oxide production and proinflammatory cytokine secretion such as TNF-α, IL-1β and IL-12 p40 as well as inducible nitric oxide synthase expression in the infected macrophages. These data showed the importance of TLR2 in the activation of macrophages following BCG and r BCG infections. Conclusions: Through exploring the immunological mechanism which underlies the protection conferred by the candidate vaccine, this study will improve our understanding of the vaccine candidate's mechanism to protect the host from malaria infection.
基金supported in the context of the Italian Malaria Network by grants from Compagnia di San Paolo-IMI and from Regione Piemonte,Ricerca Sanitaria Finalizzata 2008bis to PA
文摘Objective:To investigate whether the increase of tumor necrosis factor alpha is dependent on lipidic component of malarial pigment.Methods:Adherent human monocytes were fed for 3 hours with different meals(native hemozoin;lipid free hemozoin;and control latex particles),then tumor necrosis factor alpha was monitored in cell supernatants up to 48 hours through western blotting or specific enzyme-linked immunoadsorbent assay.In selected experiments,unfed monocytes were treated with different doses of 15(S,R)-hydroxy-6,8,11,13-eicosatetraenoic acid or 4-hydroxynonenal instead of phagocytosis.Results:Hemozoin-fed monocytes produced higher levels of tumor necrosis factor alpha than unstimulated and latex-fed cells, while lipid-free hemozoin did not reproduce these results.Additionally,hemozoin effects were mimicked dose-dependently by 15(S,R)-hydroxy-6,8,11,13-eicosatetraenoic acid,but not by 4-hydroxynonenal.Conclusions:Present data suggest an essential role for lipids in hemozoindependent enhanced release of tumor necrosis factor alpha from monocytes,and 15(S,R)hydroxy -6,8,11,13-eicosatetraenoic acid could be one possible specific mediator.
文摘A synthetic hybrid 45-peptide gene of Plasmodium falciparum (Pf), which encoded two CSP repeated peptides NANP and three merozoite peptides SPf83. 1, SPf55. 1 and SPf35. 1, was cloned in an expression vector pWR450-1, then the recombinant plasmid pWRA was introduced into the attenuated Salmonella typhimurium SL3261. When used as a live vaccine and administered orally (po), intravenously (iv) or intraperitoneally (ip),the recombinant strain was able to live in vivo and elicit specific humoral and cellular immunity in BALB/c mice and rabbits. As oral immunization is safe and effective, it is thought that the live recombinant Salmonella tyPhimurium vaccine may bring the Pf oral live vaccine a step nearer.
文摘Objective: To explore whether its antiplasmodium effect of andrographolide is attributed to its plausible effect on the plasma membrane of both Plasmodium falciparum infected and noninfected RBCs. Methods: Anti-plasmodium effect of andrographolide against Plasmodium falciparum strains was screened using the conventional malaria drug sensitivity assay. The drug was incubated with uninfected RBCs to monitor its effect on their morphology, integrity and osmotic fragility. It was incubated with the plasmodium infected RBCs to monitor its effect on the parasite induced permeation pathways. Its effect on the potential of merozoites to invade new RBCs was tested using merozoite invasion assay. Results: It showed that at andrographolide was innocuous to RBCs at concentrations approach its therapeutic level against plasmodia. Nevertheless, this inertness was dwindled at higher concentrations. Conclusions: In spite of its success to inhibit plasmodium induced permeation pathway and the potential of merozoites to invade new RBCs, its anti-plasmodium effect can't be attributed to these functions as they were attained at concentrations higher than what is required to eradicate the parasite. Consequently, other mechanisms may be associated with its claimed actions.
文摘Objective To sequence the gene encoding glutamate rich protein (GLURP) andidentify the genotypes of geographically different Plasmodium falciparum (P. f ) isolatesfrom China. Methods The gene of R2 repeat region of GLURP was amplified by nestedpolymerase chain reaction and cloned into T-vector. The nucleotide sequence of GLURPgene was determined by automatic sequencer (Dideoxy termination method) and analyzed byDNA Star software. Results At least 7 different GLURP genotypes ranging from 600 bpto 1 500 bp were found in Yunnan and Hainan provinces. R2 region of GLURP gene consistedof several repeat units. Each repeat unit was composed of 19-20 residues which were shownto be highly conserved. GLURP gene was also size polymorphic due to differences in thenumber of repeat units, whereas the repeat sequence was conserved. Sequence analysisshowed that DNA sequences and deduced amino acid sequences were highly homologousamong the geographically dispersed isolates or various isolates from the same geographicalregion. No obvious differences were found in the GLURP gene sequences amonggeographically different isolates. Conclusion GLURP gene is highly structure conservedand size polymorphic, and so is useful in searching for malaria vaccine candidate antigen anddeveloping a genotyping method for malaria research.
基金Supported by the National Research University Project(NRU)of Thailand(Grant No.10/2555)Thammasat University(Grant for student No.33/2555)
文摘Objective:To investigate the distribution and patterns of pfcrt and pfmdr1 polymorphisms in Plasmodium falciparum(P.falciparum)isolates collected from the malaria endemic area of Thailand along Thai-Myanmar border.Methods:Dried blood spot samples were collected from 172 falciparum malaria patients prior received treatment.The samples were extracted using chelex to obtain parasite DNA.PCR-RFLP was employed to detect pfert mutation at codons 76,220,271,326,3S6 and 371,and the pfmdr1mutation at codon 86.Pfmdr1 gene copy number was determined by SYBR Green 1 real-time PCR.Results:Mutant alleles of pfcrt and wild type allele of pfmdrl were found in almost all samples.Pfmdrl gene copy number in isolates collected from all areas ranged from 1.0 to S.0 copies and proportion of isolates carrying>1 gene copies was 38.1%.The distribution and patterns of pfcrt and pfmdrl mutations were similar in P.falciparum isolates from all areas.However,significant differences in both number of gfmdr1 copies and prevalence of isolates carrying>1 gene copies were observed among isolates collected from different areas.The median pfmdr1 copy number in P.falciparum collected from Kanchanaburi and Mae Hongson were 2.5 and 2.0,respectively and more than half of the isolates carried>1 gene copies.Conclusions:The observation of pfindr1 wild type and increasing of gene copy number may suggest declining of artesunate-mefloquine treatment efficacy in P.falciparum isolates in this border area.
基金Supported by a grant from Research Institute,Bansomdejchaopraya Rajabhat University(Grant no.2555)
文摘Objective:To study the genetic diversity at the msp—1,msp—2,and glurp genes of Plasmodium falciparum(P.falciparum) isolates from 3 endemic areas in Thailand:Tak.Kanchanaburi and Ranong provinces.Methods:A total of 144 P.falciparum isolates collected prior to Irealmenl during January.2012 to June,2013 were genotyped.DNA was extracted:allele frequency and diversity of msp-1.msp-2,and glurp genes were investigated by nested polymerase chain reaction.Results:P.falciparum isolates in this study had high rate of multiple genotypes infection(96.5%)with an overall mean multiplicity of infection of 3.21.The distribution of allelic families of msp-1was significantly different among isolales from Tak.kanchanahnri.and Ranong but not for the msp-2.K1 and MAD20 were the predominant allelic families at the msp-1 gene,whereas alleles belonging to 3D7 were more frequent at the msp-2 gene.The glurp gene had the least diverse alleles.Population structure of P.falciparum isolates from Tak and Ranong was quite similar as revealed by the presence of similar proportions of MAD20 and K1 alleles at msp-1 loci.3D7 and FC27 alleles at msp-2 loci as well as comparable mean MOI.Isolates from Kanchanaburi had different structures;the most prevalent alleles were K1 and RO33.Conclusions:The present study shows that P.falciparum isolates from Tak and Ranong provinces had similar allelic pattern of msp—1 and msp—2 and diversity but different from Kanchanaburi isolates.These allelic variant profiles are valuable baseline data for future epidemiological study of malaria transmission and for continued monitoring of polymorphisms associated with antimalarial drug resistance in these areas.
