Meat constitutes the main source of protein and occupies an important place in our diet. Indeed, the production of poultry and beef has increased. However, the hygienic quality of meat is not always guaranteed. Microo...Meat constitutes the main source of protein and occupies an important place in our diet. Indeed, the production of poultry and beef has increased. However, the hygienic quality of meat is not always guaranteed. Microorganisms such as Escherichia coli can be found in meat and can cause various infections including diarrhea, dysentery, food poisoning, gastroenteritis or typhoid fever. Thus, the present study was designed to characterize Escherichia coli (E. coli) from beef and chicken consumed in restaurants in Yaoundé Cameroon. A total of 105 meat samples (60 beef and 45 chickens) were subjected to microbial culture for E. coli isolation and further confirmed by Polymerase Chain Reaction (PCR) using primers EC-F and EC-R that are specific to E. coli 16S rRNA gene. The supplier source, storage, and transport conditions were taken into consideration during sample analysis and data processing. This study revealed that 77/105 samples (73.33%) were positive for E. coli following microbial culture and 35 (33.33%) were positive for E. coli following molecular examination. A statistically significant difference was observed when PCR and microbial culture were used to assess for E. coli in beef and a non-statistically significant difference was observed in the case of chicken meat. Also, a statistically significant difference was noticed with the different transport conditions, but this wasn’t the case with the supplier source as well as the storage conditions where a non-statistically significant difference was seen. This study revealed that PCR-based methods are fast and reliable in the identification and characterization of Escherichia coli in meats (beef and chicken) as well as in assessing the prevalence of pathogenic E. coli, in Cameroon.展开更多
We report a novel method for rapid,colorimetric detection of a specific deoxyribonucleic acid(DNA)sequence by carrying out a polymerase chain reaction in the presence of gold nanoparticles functionalized with two prim...We report a novel method for rapid,colorimetric detection of a specific deoxyribonucleic acid(DNA)sequence by carrying out a polymerase chain reaction in the presence of gold nanoparticles functionalized with two primers.Extension of the primers when the target DNA is present as a template during the polymerase chain reaction process affords the complementary sequences on the gold nanoparticle surfaces and results in the formation of gold nanoparticle aggregates with a concomitant color change from red to pinkish/purple.This method provides a convenient and straightforward solution for ultrasensitive DNA detection without any further post-treatment of the polymerase chain reaction products being necessary,and is a promising tool for rapid disease diagnostics and gene sequencing.展开更多
［1］Daniel JG, James RU, Cynthia A G, et al. Multiplex PCR for identification of methicillin-resistant staphylo-cocci in the clinical laboratory [J]. J Clin Microbiol,1994,32(7):1768［2］Chambers HF ,Sachdeva M. Bind...［1］Daniel JG, James RU, Cynthia A G, et al. Multiplex PCR for identification of methicillin-resistant staphylo-cocci in the clinical laboratory [J]. J Clin Microbiol,1994,32(7):1768［2］Chambers HF ,Sachdeva M. Binding of β-lactam antibi-otics to penicillin-binding proteins in methicillin-resis-tant staphylococcus aureus [J]. J Infect Dis, 1990,161:1170［3］Towner KJ,Talbot DC,Curran R, et al. Development and evaluation of a PCR-based immunoassay for the rapid detection of methicillin-resistant staphylococcus aureus[J]. J Med Microbiol, 1998,47 :607［4］Murakami KW, Minamide KW,Nakamura E, et al. I-dentification of methicillin-resistant strains of staphylo-cocci by polymerase chain reaction[J]. J Clin Microbiol,1991,29:2240［5］Hulimann-Dalel RL,Ryffel C, Kayser F H, et al. Sur-vey of the methicillin resistant -associated genes mecA,mecRI-mecI,and femA-femB in clinical isolates of me-thicillin-resistant Staphylococcus aureus[J]. Antimicrob Agents Chemother, 1992,36: 2617［6］Kopp U,Roos M ,Weck J, et al. Staphylococcal peptido-glycan interpeptide bridge biosynthesis: a novel anti-staphylococcal target[J]? Microb Drug Resist, 1996,2:29［7］Rychlik W, Spencer WJ,Rhoads R E. Optimization of the annealing temperature for DNA amplification in vitro [J]. Nucleic Acids Res, 1990,18 :展开更多
Objective To investigate the frequency of t(14; 18) in different subtypes of B-cell lymphomas and the ability or the polymerase chain reaction(PCR) to detect this rearrangement in frozen samples. Methods 1o7 cases of ...Objective To investigate the frequency of t(14; 18) in different subtypes of B-cell lymphomas and the ability or the polymerase chain reaction(PCR) to detect this rearrangement in frozen samples. Methods 1o7 cases of B-cell lymphomas were studied uslng DNA extracted from rresh-frozen tissues. The DNA samples were amplified by PCR for bcl-2 MBR/JH. The products of bcl-2/JH rearrangement were hybridized with an internal olignucleotide probe or bcl-2 MBR. Results The rearranged bcl-2MBR/JH gene was detected in 13 of the 25(52. o% ) follicular center lymphomas, according to REAL classification: 8 of 11 (72. 7%) grade 1, 2 of 5(40. 0%) grade I, and 3 of 90 (33. 3%) grade, 17 of 82(2o. 8%) cases or difruse large B-cell lymphomas were found to have detectable bel-2 MBR/J. rearrangement- Conclusion The rrequency or bcl-2 MBR/JH rearrangement in diffuse large B-cell lymphomas is significantly lower than those in follicular center lympkomas(X2= 9. 28, P <o. oo5), suggesting that bcl2/JH rearrangements occur mainly in follicular center lymphomas. in addition, the result of reconstruction experiments suggest that amplification or bcl-2 MBR/JH rearrangements by PCR is both sensitive and specific for detection of t (14; 18 ) translocation.展开更多
<p> Characterization and identification of molds based on cultural and morphological characteristics are often not reliable and frail with limitations. The occurrence of <em>Aspergillus</em> species ...<p> Characterization and identification of molds based on cultural and morphological characteristics are often not reliable and frail with limitations. The occurrence of <em>Aspergillus</em> species in garri on sale in markets in Benue State, Nigeria, was studied by molecular techniques. <em>Aspergillus</em> species were isolated and purified on Potato Dextrose Agar. DNA from the purified isolates was extracted using the ZR fungal DNA miniprep and amplified by PCR mix made up of 12.5 μL of Taq 2X Master Mix. Primer sequences for the fungi characterization were internal transcribed spacers ITS 4 and ITS 5. The phylogenetic tree was plotted between the isolated organisms and reference sequences and evolutionary analysis was conducted in MEGA X. Result revealed that one thousand, six hundred and forty-six <em>Aspergilli </em>were isolated comprising of 980 and 666 isolates from the white and yellow garri respectively. <em>Aspergillus</em> <em>flavus, A. fumigatus, A. niger, A. aculeatinus</em>, and <em>A. aculeatus</em> were identified. Twenty percent (20%) of the strains had aflatoxin D structural gene, 50% amplified AFLP and 70% of the strains expressed AFLQ genes needed for the biosynthesis of aflatoxin B1. Majority of the strains that showed the expression of these structural genes were consistent with<em> Aspergillus </em><em>flavus</em>. Phylogenetic tree showed a close relationship among the isolates and their most identical sequence in the NCBI database. </p>展开更多
Objective To investigate transfusion transmitted virus (TTV) infection among population of different groups in Shaanxi Province.Methods A nested polymerase chain reaction (PCR) with primers from ORF1 of TTV genome was...Objective To investigate transfusion transmitted virus (TTV) infection among population of different groups in Shaanxi Province.Methods A nested polymerase chain reaction (PCR) with primers from ORF1 of TTV genome was established to detect TTV DNA in serum of the patients.Results TTV DAN was detected in the sera of 3 of 50 cases of general population(6%), 2 of 30 cases of vocational blood donors(6.7%),21 of 97 cases with Type B hepatitis(21.6%),9 of 35 cases of Type C hepatitis (25.7%),and 23 of 40 cases with non A^non G hepatitis(57 5%).Conclusion There is TTV infection among general population in Shaanxi Province.TTV may be an important agent to cause non A^non G hepatitis .And the patients with HBV or HCV can have overlapping TTV infection.展开更多
White piedra is a superficial, chronic, asymptomatic mycoses caused by yeast fungi of the genus Trichosporon. It affects the hair, especially of the head, less frequently of the pubis, perineum, armpit, beard, mustach...White piedra is a superficial, chronic, asymptomatic mycoses caused by yeast fungi of the genus Trichosporon. It affects the hair, especially of the head, less frequently of the pubis, perineum, armpit, beard, mustache, eyebrows and eyelashes, and is characterized by the formation of soft nodules or fungal clusters. It affects all age groups and both sexes, predominantly women. Diagnosis is made by direct examination of the affected hair and culture on Sabouraud dextrose agar. The identification of species occurs through more specific identification procedures, such as mass spectrometry (MALDI-TOF) and PCR). The objective of this work is to report two cases of familial white piedra caused by T. inkin identified by PCR.展开更多
Nucleic acid amplification and quantification via polymerase chain reaction(PCR)is one of the most sensitive and powerful tools for clinical laboratories,precision medicine,personalized medicine,agricultural science,f...Nucleic acid amplification and quantification via polymerase chain reaction(PCR)is one of the most sensitive and powerful tools for clinical laboratories,precision medicine,personalized medicine,agricultural science,forensic science and environmental science.Ultrafast multiplex PCR,characterized by low power consumption,compact size and simple operation,is ideal for timely diagnosis at the point-of-care(POC).Although several fast/ultrafast PCR methods have been proposed,the use of a simple and robust PCR thermal cycler remains challenging for POC testing.Here,we present an ultrafast photonic PCR method using plasmonic photothermal light-to-heat conversion via photon–electron–phonon coupling.We demonstrate an efficient photonic heat converter using a thin gold(Au)film due to its plasmon-assisted high optical absorption(approximately 65%at 450 nm,the peak wavelength of heat source light-emitting diodes(LEDs)).The plasmon-excited Au film is capable of rapidly heating the surrounding solution to over 150℃ within 3 min.Using this method,ultrafast thermal cycling(30 cycles;heating and cooling rate of 12.7960.93℃ s^(-1) and 6.660.29℃ s^(-1),respectively)from 55℃(temperature of annealing)to 95℃(temperature of denaturation)is accomplished within 5 min.Using photonic PCR thermal cycles,we demonstrate here successful nucleic acid(λ-DNA)amplification.Our simple,robust and low cost approach to ultrafast PCR using an efficient photonic-based heating procedure could be generally integrated into a variety of devices or procedures,including on-chip thermal lysis and heating for isothermal amplifications.展开更多
New high-throughput technologies continue to emerge for studying complex microbial communities.In particular,massively parallel pyrosequencing enables very high numbers of sequences,providing a more complete view of c...New high-throughput technologies continue to emerge for studying complex microbial communities.In particular,massively parallel pyrosequencing enables very high numbers of sequences,providing a more complete view of community structures and a more accurate inference of the functions than has been possible just a few years ago.In parallel,quantitative real-time polymerase chain reaction(QPCR)allows quantitative monitoring of specific community members over time,space,or different environmental conditions.In this review,the principles of these two methods and their complementary applications in studying microbial ecology in bioenvironmental systems are discussed.The parallel sequencing of amplicon libraries and using barcodes to differentiate multiple samples in a pyrosequencing run are explained.The best procedures and chemistries for QPCR amplifications are also described and advantages of applying automation to increase accuracy are addressed.Three examples in which pyrosequencing and QPCR were used together to define and quantify members of microbial communities are provided:in the human large intestine,in a methanogenic digester whose sludge was made more bioavailable by a high-voltage pretreatment,and on the biofilm anode of a microbial electrolytic cell.The key findings in these systems and how both methods were used in concert to achieve those findings are highlighted.展开更多
Coronavirus disease 2019(COVID-19)has continued to spread globally since late 2019,representing a formidable challenge to the world's healthcare systems,wreaking havoc,and spreading rapidly through human contact.W...Coronavirus disease 2019(COVID-19)has continued to spread globally since late 2019,representing a formidable challenge to the world's healthcare systems,wreaking havoc,and spreading rapidly through human contact.With fever,fatigue,and a persistent dry cough being the hallmark symptoms,this disease threatened to destabilize the delicate balance of our global community.Rapid and accurate diagnosis of COVID-19 is a prerequisite for understanding the number of confirmed cases in the world or a region,and an important factor in epidemic assessment and the development of control measures.It also plays a crucial role in ensuring that patients receive the appropriate medical treatment,leading to optimal patient care.Reverse transcription-polymerase chain reaction(RT-PCR)technology is currently the most mature method for detecting viral nucleic acids,but it has many drawbacks.Meanwhile,a variety of COVID-19 detection methods,including molecular biological diagnostic,immunodiagnostic,imaging,and artificial intelligence methods have been developed and applied in clinical practice to meet diverse scenarios and needs.These methods can help clinicians diagnose and treat COVID-19 patients.This review describes the variety of such methods used in China,providing an important reference in the field of the clinical diagnosis of COVID-19.展开更多
Biologically,there exist two kinds of syntheses:photosynthesis and ATP-driven biosynthesis.The light harvesting of photosynthesis is known to achieve an efficiency of〜95%by the quantum energy transfer of photons.Howev...Biologically,there exist two kinds of syntheses:photosynthesis and ATP-driven biosynthesis.The light harvesting of photosynthesis is known to achieve an efficiency of〜95%by the quantum energy transfer of photons.However,how the ATP-driven biosynthesis reaches its high efficiency still remains unknown.Deoxynucleotide triphosphates(dNTPs)in polymerase chain reaction(PCR)adopt the identical way of ATP to release their energy,and thus can be employed to explore the ATP energy process.Here,using a gold nanoparticle(AuNP)enhanced PCR(AuNP-PCR),we demonstrate that the energy released by phosphoanhydride-bond(PB)hydrolysis of dNTPs is in form of photons(PB-photons)to drive DNA replication,by modulating their resonance with the average inter-AuNP distance(D).The experimental results show that both the efficiency and yield of PCR periodically oscillate with D increasing,indicating a quantized process,but not simply a thermal one.The PB-photon wavelength is further determined to 8.4 pm.All these results support that the release,transfer and utilization of bioenergy are in the form of photons.Our findings of ATP-energy quantum conversion will open a new avenue to the studies of high-efficiency bioenergy utilization,biochemistry,biological quantum physics,and even brain sciences.展开更多
To understand the influence patterns and interactions of three important environmental factors,i.e.soil water content,oxygen concentration,and ammonium addition,on methane oxidation,the soils from landfill cover layer...To understand the influence patterns and interactions of three important environmental factors,i.e.soil water content,oxygen concentration,and ammonium addition,on methane oxidation,the soils from landfill cover layers were incubated under full factorial parameter settings.In addition to the methane oxidation rate,the quantities and community structures of methanotrophs were analyzed to determine the methane oxidation capacity of the soils.Canonical correspondence analysis was utilized to distinguish the important impact factors.Water content was found to be the most important factor influencing the methane oxidation rate and Type II methanotrophs,and the optimum value was 15%(w/w),which induced methane oxidation rates 10-and 6-times greater than those observed at 5%(w/w)and 20%(w/w),respectively.Ambient oxygen conditions were more suitable for methane oxidation than 3%oxygen.The addition of 100 mg-N·kg^(-1) drysoil of ammonium induced different effects on methane oxidation capacity when conducted at low or high water content.With regard to the methanotrophs,Type II was sensitive to the changes of water content,while Type I was influenced by oxygen content.Furthermore,the methanotrophic acidophile,Verrucomicrobia,was detected in soils with a pH of 4.9,which extended their known living environments.展开更多
Activated sludge was monthly sampled from a saline sewage treatment plant of Hong Kong(China)during June 2007 to May 2008 to analyze the microbial community shift along with environmental variations using denaturing g...Activated sludge was monthly sampled from a saline sewage treatment plant of Hong Kong(China)during June 2007 to May 2008 to analyze the microbial community shift along with environmental variations using denaturing gradient gel electrophoresis of polymerase chain reaction amplified 16S rDNA fragments.Environmental changes resulted into a seasonal microbial community shift characterized by alterations in species number and abundance in the sewage treatment plant.Correspondence analysis and cluster analysis on community structure profile showed that the 12 monthly samples fell into four groups,which is in accordance with season changing in Hong Kong.Canonical correspondence analysis revealed that PO_(4)^(3-)-P and NH_(4)^(+)-N posed more significant effects on community structure than total phosphorus and total nitrogen,respectively.Compared with sludge retention time,influent total phosphorus had an inverse effect on the community structure shift,and chemical oxygen demand and NH_(4)^(+)-N showed a similar effects.Results of this study may contribute to the development of new knowledge involving the microbial community shift in sewage treatment plants.展开更多
Hallucinogenic mushroom is a kind of toxic strain containing psychoactive tryptamine substances such as psilocybin,psilocin and ibotenic acid,etc.The mushrooms containing hallucinogenic components are various,widely d...Hallucinogenic mushroom is a kind of toxic strain containing psychoactive tryptamine substances such as psilocybin,psilocin and ibotenic acid,etc.The mushrooms containing hallucinogenic components are various,widely distributed and lack of standard to define,which made a great challenge to identification.Traditional identification methods,such as morphology and toxicology analysis,showed shortcomings in old or processed samples,while the DNA-based identification of hallucinogenic mushrooms would allow to identify these samples due to the stability of DNA.In this paper,four primer sets are designed to target Psilocybe cubensis DNA for increasing resolution of present identification method,and the target markers include largest subunit of RNA polymerase II(marked as PC-R1),psilocybin-related phosphotransferase gene(marked as PC-PT),glyceraldehyde 3-phosphate dehydrogenase(marked as PC-3)and translation EF1α(marked as PC-EF).Real-time PCR with high-resolution melting(HRM)assay were used for the differentiation of the fragments amplified by these primer sets,which were tested for specificity,reproducibility,sensitivity,mixture analysis and multiplex PCR.It was shown that the melting temperatures of PC-R1,PC-PT,PC-3 and PC-EF of P.cubensis were(87.93±0.12)℃,(82.21±0.14)℃,(79.72±0.12)℃ and(80.11±0.19)℃ in our kinds of independent experiments.Significant HRM characteristic can be shown with a low concentration of 62.5pg/µL DNA sample,and P.cubensis could be detected in mixtures with Homo sapiens or Cannabis sativa.In summary,the method of HRM analysis can quickly and specifically distinguish P.cubensis from other species,which could be utilized for forensic science,medical diagnosis and drug trafficking cases.展开更多
文摘Meat constitutes the main source of protein and occupies an important place in our diet. Indeed, the production of poultry and beef has increased. However, the hygienic quality of meat is not always guaranteed. Microorganisms such as Escherichia coli can be found in meat and can cause various infections including diarrhea, dysentery, food poisoning, gastroenteritis or typhoid fever. Thus, the present study was designed to characterize Escherichia coli (E. coli) from beef and chicken consumed in restaurants in Yaoundé Cameroon. A total of 105 meat samples (60 beef and 45 chickens) were subjected to microbial culture for E. coli isolation and further confirmed by Polymerase Chain Reaction (PCR) using primers EC-F and EC-R that are specific to E. coli 16S rRNA gene. The supplier source, storage, and transport conditions were taken into consideration during sample analysis and data processing. This study revealed that 77/105 samples (73.33%) were positive for E. coli following microbial culture and 35 (33.33%) were positive for E. coli following molecular examination. A statistically significant difference was observed when PCR and microbial culture were used to assess for E. coli in beef and a non-statistically significant difference was observed in the case of chicken meat. Also, a statistically significant difference was noticed with the different transport conditions, but this wasn’t the case with the supplier source as well as the storage conditions where a non-statistically significant difference was seen. This study revealed that PCR-based methods are fast and reliable in the identification and characterization of Escherichia coli in meats (beef and chicken) as well as in assessing the prevalence of pathogenic E. coli, in Cameroon.
基金This work was supported by the“Bairen Jihua”program of Chinese Academy of Sciences,the Chinese Academy of Sciences/State Administration of Foreign Experts Affairs(CAS/SAFEA)International Partnership Program for Creative Research Teams and Suzhou Bureau of Science and Technology.
文摘We report a novel method for rapid,colorimetric detection of a specific deoxyribonucleic acid(DNA)sequence by carrying out a polymerase chain reaction in the presence of gold nanoparticles functionalized with two primers.Extension of the primers when the target DNA is present as a template during the polymerase chain reaction process affords the complementary sequences on the gold nanoparticle surfaces and results in the formation of gold nanoparticle aggregates with a concomitant color change from red to pinkish/purple.This method provides a convenient and straightforward solution for ultrasensitive DNA detection without any further post-treatment of the polymerase chain reaction products being necessary,and is a promising tool for rapid disease diagnostics and gene sequencing.
基金This study was supported by the British Society for Antimicrobial Chemotherapy (BSAC)
文摘［1］Daniel JG, James RU, Cynthia A G, et al. Multiplex PCR for identification of methicillin-resistant staphylo-cocci in the clinical laboratory [J]. J Clin Microbiol,1994,32(7):1768［2］Chambers HF ,Sachdeva M. Binding of β-lactam antibi-otics to penicillin-binding proteins in methicillin-resis-tant staphylococcus aureus [J]. J Infect Dis, 1990,161:1170［3］Towner KJ,Talbot DC,Curran R, et al. Development and evaluation of a PCR-based immunoassay for the rapid detection of methicillin-resistant staphylococcus aureus[J]. J Med Microbiol, 1998,47 :607［4］Murakami KW, Minamide KW,Nakamura E, et al. I-dentification of methicillin-resistant strains of staphylo-cocci by polymerase chain reaction[J]. J Clin Microbiol,1991,29:2240［5］Hulimann-Dalel RL,Ryffel C, Kayser F H, et al. Sur-vey of the methicillin resistant -associated genes mecA,mecRI-mecI,and femA-femB in clinical isolates of me-thicillin-resistant Staphylococcus aureus[J]. Antimicrob Agents Chemother, 1992,36: 2617［6］Kopp U,Roos M ,Weck J, et al. Staphylococcal peptido-glycan interpeptide bridge biosynthesis: a novel anti-staphylococcal target[J]? Microb Drug Resist, 1996,2:29［7］Rychlik W, Spencer WJ,Rhoads R E. Optimization of the annealing temperature for DNA amplification in vitro [J]. Nucleic Acids Res, 1990,18 :
文摘Objective To investigate the frequency of t(14; 18) in different subtypes of B-cell lymphomas and the ability or the polymerase chain reaction(PCR) to detect this rearrangement in frozen samples. Methods 1o7 cases of B-cell lymphomas were studied uslng DNA extracted from rresh-frozen tissues. The DNA samples were amplified by PCR for bcl-2 MBR/JH. The products of bcl-2/JH rearrangement were hybridized with an internal olignucleotide probe or bcl-2 MBR. Results The rearranged bcl-2MBR/JH gene was detected in 13 of the 25(52. o% ) follicular center lymphomas, according to REAL classification: 8 of 11 (72. 7%) grade 1, 2 of 5(40. 0%) grade I, and 3 of 90 (33. 3%) grade, 17 of 82(2o. 8%) cases or difruse large B-cell lymphomas were found to have detectable bel-2 MBR/J. rearrangement- Conclusion The rrequency or bcl-2 MBR/JH rearrangement in diffuse large B-cell lymphomas is significantly lower than those in follicular center lympkomas(X2= 9. 28, P <o. oo5), suggesting that bcl2/JH rearrangements occur mainly in follicular center lymphomas. in addition, the result of reconstruction experiments suggest that amplification or bcl-2 MBR/JH rearrangements by PCR is both sensitive and specific for detection of t (14; 18 ) translocation.
文摘<p> Characterization and identification of molds based on cultural and morphological characteristics are often not reliable and frail with limitations. The occurrence of <em>Aspergillus</em> species in garri on sale in markets in Benue State, Nigeria, was studied by molecular techniques. <em>Aspergillus</em> species were isolated and purified on Potato Dextrose Agar. DNA from the purified isolates was extracted using the ZR fungal DNA miniprep and amplified by PCR mix made up of 12.5 μL of Taq 2X Master Mix. Primer sequences for the fungi characterization were internal transcribed spacers ITS 4 and ITS 5. The phylogenetic tree was plotted between the isolated organisms and reference sequences and evolutionary analysis was conducted in MEGA X. Result revealed that one thousand, six hundred and forty-six <em>Aspergilli </em>were isolated comprising of 980 and 666 isolates from the white and yellow garri respectively. <em>Aspergillus</em> <em>flavus, A. fumigatus, A. niger, A. aculeatinus</em>, and <em>A. aculeatus</em> were identified. Twenty percent (20%) of the strains had aflatoxin D structural gene, 50% amplified AFLP and 70% of the strains expressed AFLQ genes needed for the biosynthesis of aflatoxin B1. Majority of the strains that showed the expression of these structural genes were consistent with<em> Aspergillus </em><em>flavus</em>. Phylogenetic tree showed a close relationship among the isolates and their most identical sequence in the NCBI database. </p>
基金supported by Natural Science Foundation of Shaanxi Province(No.2000 SM56)
文摘Objective To investigate transfusion transmitted virus (TTV) infection among population of different groups in Shaanxi Province.Methods A nested polymerase chain reaction (PCR) with primers from ORF1 of TTV genome was established to detect TTV DNA in serum of the patients.Results TTV DAN was detected in the sera of 3 of 50 cases of general population(6%), 2 of 30 cases of vocational blood donors(6.7%),21 of 97 cases with Type B hepatitis(21.6%),9 of 35 cases of Type C hepatitis (25.7%),and 23 of 40 cases with non A^non G hepatitis(57 5%).Conclusion There is TTV infection among general population in Shaanxi Province.TTV may be an important agent to cause non A^non G hepatitis .And the patients with HBV or HCV can have overlapping TTV infection.
文摘White piedra is a superficial, chronic, asymptomatic mycoses caused by yeast fungi of the genus Trichosporon. It affects the hair, especially of the head, less frequently of the pubis, perineum, armpit, beard, mustache, eyebrows and eyelashes, and is characterized by the formation of soft nodules or fungal clusters. It affects all age groups and both sexes, predominantly women. Diagnosis is made by direct examination of the affected hair and culture on Sabouraud dextrose agar. The identification of species occurs through more specific identification procedures, such as mass spectrometry (MALDI-TOF) and PCR). The objective of this work is to report two cases of familial white piedra caused by T. inkin identified by PCR.
基金This work was supported in part by a grant from the Bill&Melinda Gates Foundation(Global Health Grant:OPP1028785)in part by the Global Research Lab Program(2013-050616)through the National Research Foundation of Korea funded by the Ministry of Science,ICT(Information and Communication Technologies)and Future Planning.
文摘Nucleic acid amplification and quantification via polymerase chain reaction(PCR)is one of the most sensitive and powerful tools for clinical laboratories,precision medicine,personalized medicine,agricultural science,forensic science and environmental science.Ultrafast multiplex PCR,characterized by low power consumption,compact size and simple operation,is ideal for timely diagnosis at the point-of-care(POC).Although several fast/ultrafast PCR methods have been proposed,the use of a simple and robust PCR thermal cycler remains challenging for POC testing.Here,we present an ultrafast photonic PCR method using plasmonic photothermal light-to-heat conversion via photon–electron–phonon coupling.We demonstrate an efficient photonic heat converter using a thin gold(Au)film due to its plasmon-assisted high optical absorption(approximately 65%at 450 nm,the peak wavelength of heat source light-emitting diodes(LEDs)).The plasmon-excited Au film is capable of rapidly heating the surrounding solution to over 150℃ within 3 min.Using this method,ultrafast thermal cycling(30 cycles;heating and cooling rate of 12.7960.93℃ s^(-1) and 6.660.29℃ s^(-1),respectively)from 55℃(temperature of annealing)to 95℃(temperature of denaturation)is accomplished within 5 min.Using photonic PCR thermal cycles,we demonstrate here successful nucleic acid(λ-DNA)amplification.Our simple,robust and low cost approach to ultrafast PCR using an efficient photonic-based heating procedure could be generally integrated into a variety of devices or procedures,including on-chip thermal lysis and heating for isothermal amplifications.
文摘New high-throughput technologies continue to emerge for studying complex microbial communities.In particular,massively parallel pyrosequencing enables very high numbers of sequences,providing a more complete view of community structures and a more accurate inference of the functions than has been possible just a few years ago.In parallel,quantitative real-time polymerase chain reaction(QPCR)allows quantitative monitoring of specific community members over time,space,or different environmental conditions.In this review,the principles of these two methods and their complementary applications in studying microbial ecology in bioenvironmental systems are discussed.The parallel sequencing of amplicon libraries and using barcodes to differentiate multiple samples in a pyrosequencing run are explained.The best procedures and chemistries for QPCR amplifications are also described and advantages of applying automation to increase accuracy are addressed.Three examples in which pyrosequencing and QPCR were used together to define and quantify members of microbial communities are provided:in the human large intestine,in a methanogenic digester whose sludge was made more bioavailable by a high-voltage pretreatment,and on the biofilm anode of a microbial electrolytic cell.The key findings in these systems and how both methods were used in concert to achieve those findings are highlighted.
基金supported by the Emergency Key Project of Guangzhou Laboratory(No.EKPG21-30-2),China.
文摘Coronavirus disease 2019(COVID-19)has continued to spread globally since late 2019,representing a formidable challenge to the world's healthcare systems,wreaking havoc,and spreading rapidly through human contact.With fever,fatigue,and a persistent dry cough being the hallmark symptoms,this disease threatened to destabilize the delicate balance of our global community.Rapid and accurate diagnosis of COVID-19 is a prerequisite for understanding the number of confirmed cases in the world or a region,and an important factor in epidemic assessment and the development of control measures.It also plays a crucial role in ensuring that patients receive the appropriate medical treatment,leading to optimal patient care.Reverse transcription-polymerase chain reaction(RT-PCR)technology is currently the most mature method for detecting viral nucleic acids,but it has many drawbacks.Meanwhile,a variety of COVID-19 detection methods,including molecular biological diagnostic,immunodiagnostic,imaging,and artificial intelligence methods have been developed and applied in clinical practice to meet diverse scenarios and needs.These methods can help clinicians diagnose and treat COVID-19 patients.This review describes the variety of such methods used in China,providing an important reference in the field of the clinical diagnosis of COVID-19.
基金the National Key Research and Development Program of China(No.2018YFE0205501)the National Natural Science Foundation of China Projects(Nos.51763019,U1832125,31630029)the National Supercomputer Center in Tianjin.
文摘Biologically,there exist two kinds of syntheses:photosynthesis and ATP-driven biosynthesis.The light harvesting of photosynthesis is known to achieve an efficiency of〜95%by the quantum energy transfer of photons.However,how the ATP-driven biosynthesis reaches its high efficiency still remains unknown.Deoxynucleotide triphosphates(dNTPs)in polymerase chain reaction(PCR)adopt the identical way of ATP to release their energy,and thus can be employed to explore the ATP energy process.Here,using a gold nanoparticle(AuNP)enhanced PCR(AuNP-PCR),we demonstrate that the energy released by phosphoanhydride-bond(PB)hydrolysis of dNTPs is in form of photons(PB-photons)to drive DNA replication,by modulating their resonance with the average inter-AuNP distance(D).The experimental results show that both the efficiency and yield of PCR periodically oscillate with D increasing,indicating a quantized process,but not simply a thermal one.The PB-photon wavelength is further determined to 8.4 pm.All these results support that the release,transfer and utilization of bioenergy are in the form of photons.Our findings of ATP-energy quantum conversion will open a new avenue to the studies of high-efficiency bioenergy utilization,biochemistry,biological quantum physics,and even brain sciences.
基金This work was financially supported by the National Key Technology R&D Program of China(No.2006BAJ04A06)the National High-Tech Research and Development Program(863 Program)of China(No.2003AA644020).
文摘To understand the influence patterns and interactions of three important environmental factors,i.e.soil water content,oxygen concentration,and ammonium addition,on methane oxidation,the soils from landfill cover layers were incubated under full factorial parameter settings.In addition to the methane oxidation rate,the quantities and community structures of methanotrophs were analyzed to determine the methane oxidation capacity of the soils.Canonical correspondence analysis was utilized to distinguish the important impact factors.Water content was found to be the most important factor influencing the methane oxidation rate and Type II methanotrophs,and the optimum value was 15%(w/w),which induced methane oxidation rates 10-and 6-times greater than those observed at 5%(w/w)and 20%(w/w),respectively.Ambient oxygen conditions were more suitable for methane oxidation than 3%oxygen.The addition of 100 mg-N·kg^(-1) drysoil of ammonium induced different effects on methane oxidation capacity when conducted at low or high water content.With regard to the methanotrophs,Type II was sensitive to the changes of water content,while Type I was influenced by oxygen content.Furthermore,the methanotrophic acidophile,Verrucomicrobia,was detected in soils with a pH of 4.9,which extended their known living environments.
基金This research was supported by Hong Kong General Research Fund(HKU7195/06E)the authors would like to thank HKU Faculty of Engineering to support Dr.X.X.Zhang with the PostDoctoral Fellowship.
文摘Activated sludge was monthly sampled from a saline sewage treatment plant of Hong Kong(China)during June 2007 to May 2008 to analyze the microbial community shift along with environmental variations using denaturing gradient gel electrophoresis of polymerase chain reaction amplified 16S rDNA fragments.Environmental changes resulted into a seasonal microbial community shift characterized by alterations in species number and abundance in the sewage treatment plant.Correspondence analysis and cluster analysis on community structure profile showed that the 12 monthly samples fell into four groups,which is in accordance with season changing in Hong Kong.Canonical correspondence analysis revealed that PO_(4)^(3-)-P and NH_(4)^(+)-N posed more significant effects on community structure than total phosphorus and total nitrogen,respectively.Compared with sludge retention time,influent total phosphorus had an inverse effect on the community structure shift,and chemical oxygen demand and NH_(4)^(+)-N showed a similar effects.Results of this study may contribute to the development of new knowledge involving the microbial community shift in sewage treatment plants.
基金supported by grants from the Shanghai Areas of Development for Society Planning Projects[grant number 19dz1200600]the National Natural Science Foundation of China[grant numbers 81930056 and 81625013]the National Youth Talent Support Program[grant number WRQB2019].
文摘Hallucinogenic mushroom is a kind of toxic strain containing psychoactive tryptamine substances such as psilocybin,psilocin and ibotenic acid,etc.The mushrooms containing hallucinogenic components are various,widely distributed and lack of standard to define,which made a great challenge to identification.Traditional identification methods,such as morphology and toxicology analysis,showed shortcomings in old or processed samples,while the DNA-based identification of hallucinogenic mushrooms would allow to identify these samples due to the stability of DNA.In this paper,four primer sets are designed to target Psilocybe cubensis DNA for increasing resolution of present identification method,and the target markers include largest subunit of RNA polymerase II(marked as PC-R1),psilocybin-related phosphotransferase gene(marked as PC-PT),glyceraldehyde 3-phosphate dehydrogenase(marked as PC-3)and translation EF1α(marked as PC-EF).Real-time PCR with high-resolution melting(HRM)assay were used for the differentiation of the fragments amplified by these primer sets,which were tested for specificity,reproducibility,sensitivity,mixture analysis and multiplex PCR.It was shown that the melting temperatures of PC-R1,PC-PT,PC-3 and PC-EF of P.cubensis were(87.93±0.12)℃,(82.21±0.14)℃,(79.72±0.12)℃ and(80.11±0.19)℃ in our kinds of independent experiments.Significant HRM characteristic can be shown with a low concentration of 62.5pg/µL DNA sample,and P.cubensis could be detected in mixtures with Homo sapiens or Cannabis sativa.In summary,the method of HRM analysis can quickly and specifically distinguish P.cubensis from other species,which could be utilized for forensic science,medical diagnosis and drug trafficking cases.
