Objective:To access the in vitro antibacterial activity of Hibiscus rosa-sinensis(H.rosa-sinensis) flower extract against human pathogens.Methods:Antibacterial activity was evaluated by using disc and agar diffusion m...Objective:To access the in vitro antibacterial activity of Hibiscus rosa-sinensis(H.rosa-sinensis) flower extract against human pathogens.Methods:Antibacterial activity was evaluated by using disc and agar diffusion methods.The protein was run through poly acrylmide gel electrophoresis to view their protein profile.Results:The results showed that the cold extraction illustrates a maximum zone of inhibition against Bacillus suhtillis(B.suhtillis),Escherichia coli(E.coli) viz.,(17.00±2.91),(14.50±1.71)mm.followed by hot extraction against.E.coli.Salmonella sp.as(11.66 ±3.14),(10.60±3.09)mm.In methanol extraction showed a highest zone of inhibition recorded against B.suhtillis,E.coli as(18.86±0.18),(18.00±1.63) mm pursued by ethanol extraction shower) utmost zone of inhibition recorded against Salmonella sp.at(20.40±1.54) mm.The crude protein from flower showed a maximum inhibitory zone observed against Salmonella sp.,E.coli viz.,(16.55±1.16),(14.30±2.86)mm.The flower material can be taken as an alternative source of antibacterial agent against the human pathogens.Conclusions:The extracts of the H.rosasinensis art;proved to have potential antibacterial activity,further studies arc highly need for the drug development.展开更多
Objective:To investigate in vitro and in vivo antibacterial potentials of Vitex negundo(V. negundo) leaf extracts against diverse enteric pathogens.Methods:Water and methanol extracts of V.negundo leaves were evaluate...Objective:To investigate in vitro and in vivo antibacterial potentials of Vitex negundo(V. negundo) leaf extracts against diverse enteric pathogens.Methods:Water and methanol extracts of V.negundo leaves were evaluated against enteric bacterial pathogens by using standard disc diffusion,viable bacterial cell count methods,determination of minimum inhibitory concentrations(MIC) and minimum bactericidal concentrations(MBC).Results:Methanol extract of V.negundo leaves showed potent antibacterial activity(inhibition zone:9.9-22.6 mm,MIC: 200-3 200μg/mL.MBC:200-6 400μg/mL) against all the pathogenic enteric bacteria(Vibrio cholerae.Vibrio parahemolyticus.Vibrio mimicus.Echerichia coli,Shigella spps.,and Aeromonas spps) tested.Methanol extract of V.negundo leaves showed potent bactericidal activity both in vitro laboratory conditions(MBC,200-400μg/mL) and in the intestinal environment(Dose,1-2 mg/mL) of infant mice against pathogenic Vibrio cholerae,the major causative agent of cholera. Furthermore,assays using the mice cholera model showed that V.negundo methanol extract can protect mice from Vibrio cholerae infection and significandy decrease the mortality rate(P【0.0001). Conclusions:For the first time we showed thal medianol extract of V.negundo leaves exhibited strong vihriocidal activity both in vitro and in vivo conditions.Therefore,it will he useful to identify and isolate the active compounds of this extract that could be a good alternative of antibiotics to treat cholera.展开更多
Objective:To investigate in vitro and in vivo antibacterial potentials of Vitex negundo(V. negundo) leaf extracts against diverse enteric pathogens.Methods:Water and methanol extracts of V.negundo leaves were evaluate...Objective:To investigate in vitro and in vivo antibacterial potentials of Vitex negundo(V. negundo) leaf extracts against diverse enteric pathogens.Methods:Water and methanol extracts of V.negundo leaves were evaluated against enteric bacterial pathogens by using standard disc diffusion,viable bacterial cell count methods,determination of minimum inhibitory concentrations(MIC) and minimum bactericidal concentrations(MBC).Results:Methanol extract of V.negundo leaves showed potent antibacterial activity(inhibition zone:9.9- 22.6 mm,MIC: 200-3 200μg/mL,MBC:200-6 400μg/mL) against all the pathogenic enleric bacteria(Vibrio cholerae,Vibrio parahaemolyticus,Vibrio mimicus,Echerichia coli.Shigella spps.,and Aeromonas spps) tested.Methanol extract of V.negundo leaves showed potent bactericidal activity both in vitro laboratory conditions(MBC,200-400μg/mL) and in the intestinal environment(Dose,1-2 mg/mL) of infant mice against pathogenic Vibrio cholerae,the major causative agent of cholera. Furthermore,assays using the mice cholera model showed that V.negundo methanol extract can protect mice from Vibrio cholerae infection and significantly decrease the mortality rate(P【0.0001).Conclusioas:For the first time we showed that methanol extract of V.negundo leaves exhibited strong vibriocidal activity both in vitro and in vivo conditions.Therefore,it will be useful to identify and isolate the active compounds of this extract that could be a good alternative of antibiotics to treat cholera.展开更多
Five wild plant species belonging to different families (Chenopodium album, Plantago major, Elytrigia elongata, Filipendula ulmaria and Nigella sativa) widely spread in Russian Federation and the former USSR were eval...Five wild plant species belonging to different families (Chenopodium album, Plantago major, Elytrigia elongata, Filipendula ulmaria and Nigella sativa) widely spread in Russian Federation and the former USSR were evaluated for their ability to inhibit growth of two important human food-borne pathogens (Escherichia coli O157:H7 and Listeria monocytogenes strain EGD-e) and eight plant pathogens (Alternaria alternata, Alternaria tenuissima, Bipolaris sorokiniana, Stagonospora nodorum, Fusarium solani, Fusarium oxysporum, Fusarium culmorum and Phytophtora infestans). To isolate biologically active compounds from seeds, a step-wise procedure including extraction with hexane, ethyl acetate, ethanol, and 10% acetic acid followed by reversed-phase HPLC was developed. Using disc-diffusion assay, the highest activity against E. coli O157:H7 was observed with extracts from F. ulmaria (hexane and ethyl acetate extracts and the unbound RP-HPLC fraction) and P. major (ethyl acetate extract and the unbound RP-HPLC fraction);E. elongate (the unbound RP-HPLC fraction) was less active. The extracts from P. major and E. elongate (the unbound RP-HPLC fractions) were equally highly active against L. monocytogenes, while those of F. ulmaria (the unbound RP-HPLC fraction) and N. sativa (hexane and ethyl acetate extracts) were less active against this pathogen. The dynamics of L. monocytogenes EGD-е and E. coli O157:H7 growth in the presence of two most potent extracts (RP-HPLC-unbound fractions of P. major and E. elongate and the hexane extract of F. ulmaria) was studied.展开更多
The study aimed to evaluate the endophytic fungi isolated from <em>Cocos nucifera</em> (L.) cotyledon for their possible antimicrobial activity. A total of twelve endophytic fungal species were successfull...The study aimed to evaluate the endophytic fungi isolated from <em>Cocos nucifera</em> (L.) cotyledon for their possible antimicrobial activity. A total of twelve endophytic fungal species were successfully isolated, from which five were selected and presumptively identified, including <em>Aspergillus niger</em>, <em>Raffaelea sp.</em>, <em>Aspergillus flavus</em>, <em>Cladosporium sp.</em> and <em>Pseudallescheria spp.</em> based on their macro and microscopic characters. The agar blocks of actively growing pure culture were assessed for antibacterial activity against five human pathogenic bacterial and fungal strains: <em>Escherichia coli</em> (BIOTECH 1634), <em>Bacillus subtilis</em> (BIOTECH 1697), <em>Staphylococcus aureus</em> (BIOTECH 1592), <em>Serratia marcescens</em> (BIOTECH 1748), and <em>Candida tropicalis</em> (BIOTECH 2085). Among the selected five endophytic used for antimicrobial activity screening, the <em>Raffaelea sp.</em> (CN-EF 2) has shown a high zone of inhibition of 11 mm against <em>Bacillus subtilis</em>, 18 mm against <em>Escherichia coli</em>, 15 mm against <em>Staphylococcus aureus</em>, and 11 mm against <em>Candida tropicalis</em>. Correspondingly, <em>Aspergillus niger</em> (CN-EF 1) has shown a zone of inhibition of 16 mm against <em>C. tropicalis</em>. The endophytic fungus <em>Raffaelea sp.</em> was effective against all test organisms except for <em>Serratia marcescens</em>, while <em>Aspergillus niger</em> was only effective for pathogenic fungi <em>C. albicans</em>. Hence, further in-depth studies of the isolated endophytic fungi are needed to determine the mechanisms behind the endophytes’ inhibitory effects.展开更多
Objective:To investigate antibacterial potential of Trifolium alexandrinum(T.alexandrinum) Linn,against seven gram positive and eleven gram negative hospital isolated human pathogenic bacterial strains responsible for...Objective:To investigate antibacterial potential of Trifolium alexandrinum(T.alexandrinum) Linn,against seven gram positive and eleven gram negative hospital isolated human pathogenic bacterial strains responsible for many tropical diseases.Methods:Non-polar and polar extracts of the leaves of T.alexandrinum i.e.,hexane,dichloromethane(DCM),ethyl acetate(EtOAc), methanol(MeOH) and aqueous(AQ) extracts at five different concentrations(1,2,5,10 and 15 mg/ mL) were prepared to evaluate their antibacterial value.NCCL standards were strictly followed to perform antimicrobial disc susceptibility test using disc diffusion method.Results:Polar extracts demonstrated significant antibacterial activity against tested pathogens.EtOAc and MeOH extracts showed maximum antibacterial activity with higher inhibition zone and were found effective against seventeen of the tested pathogens.While AQ plant extract inhibited the growth of sixteen of the test strains.EtOAc and MeOH plant extracts inhibited the growth of all seven gram positive and ten of the gram negative bacterial strains.Conclusions:The present study strongly confirms the effectiveness of crude leaves extracts against tested human pathogenic bacterial strains causing several tropical diseases.Since Egyptian clover is used as a fodder plant,it could be helpful in controlling various infectious diseases associated with cattle as well.展开更多
Acorus tatarinowii Schott is a traditional Chinese medicine plant and has multiple bioactivities in medicine and pesticide field. In this study, the antifungal compound 1,2-dimethoxy-4（2-propenyl） benzene was isolat...Acorus tatarinowii Schott is a traditional Chinese medicine plant and has multiple bioactivities in medicine and pesticide field. In this study, the antifungal compound 1,2-dimethoxy-4（2-propenyl） benzene was isolated from A. tatarinowii Schott by activity-directed isolation method, and the inhibitory activity of the extract and 1,2-dimethoxy-4（2-propenyl） benzene against seven plant pathogenic fungi was evaluated. The results showed that the extract and 1,2-dimethoxy-4（2- propenyl） benzene had high inhibitory activity against hyphal growth of Thielaviopsis paradoxa （de Seynes） V. Hohnel, Pestalotia mangiferae P. Henn., Fusarium oxysporum f. sp. niveum （E. F. Smith） Syn. et Hans., Alternaria alternate Tanaka, Colletotrichum musae （Berk et Curt） V. Arx, Sphaceloma fawcettii Jenk., and Mycosphaerella sentina （Fr.） Schroter. The EC50 values of extract were 1.6162, 1.6811, 1.1253, 3.5771, 1.7024, 2.2284, and 2.2221 g L^-1, respectively, and the EC50 values of 1,2-dimethoxy-4（2-propenyl） benzene were 0.1021, 0.0997, 0.0805, 0.1742, 0.1503, 0.1853, and 0.1924 g L^-1, respectively. 1,2-Dimethoxy-4（2-propenyl） benzene also inhibited spores germination of T. paradoxa （de Seynes） V. Hohnel and F. oxysporum f. sp. niveum （E. F. Smith） Syn. et Hans., with the inhibitory rates of 98.81 and 100% at a concentration of 0.4 g L^-1 after 8 h, respectively. 1,2-Dimethoxy-4（2-propenyl） benzene is a potential botanical antifungal agent for controling of plant fungal diseases.展开更多
Endophytes,as crucial components of plant microbial communities,significantly contribute to enhancing the absorption of nutrients such as nitrogen and phosphorus by their hosts,promote plant growth,and degrade pathoge...Endophytes,as crucial components of plant microbial communities,significantly contribute to enhancing the absorption of nutrients such as nitrogen and phosphorus by their hosts,promote plant growth,and degrade pathogenic fungal mycelia.In this study,an experiment was conducted in August 2022 to explore the growth-promoting potential of endophytic bacterial strains isolated from two medical plant species,Thymus altaicus and Salvia deserta,using a series of screening media.Plant samples of Thymus altaicus and Salvia deserta were collected from Zhaosu County and Habahe County in Xinjiang Uygur Autonomous Region,China,in July 2021.Additionally,the inhibitory effects of endophytic bacterial strains on the four pathogenic fungi(Fusarium oxysporum,Fulvia fulva,Alternaria solani,and Valsa mali)were determined through the plate confrontation method.A total of 80 endophytic bacterial strains were isolated from Thymus altaicus,while a total of 60 endophytic bacterial strains were isolated from Salvia deserta.The endophytic bacterial strains from both Thymus altaicus and Salvia deserta exhibited plant growth-promoting properties.Specifically,the strains of Bacillus sp.TR002,Bacillus sp.TR005,Microbacterium sp.TSB5,and Rhodococcus sp.TR013 demonstrated strong cellulase-producing activity,siderophore-producing activity,phosphate solubilization activity,and nitrogen-fixing activity,respectively.Out of 140 endophytic bacterial strains isolated from Thymus altaicus and Salvia deserta,104 strains displayed anti-fungal activity against Fulvia fulva,Alternaria solani,Fusarium oxysporum,and Valsa mali.Furthermore,the strains of Bacillus sp.TR005,Bacillus sp.TS003,and Bacillus sp.TSB7 exhibited robust inhibition rates against all the four pathogenic fungi.In conclusion,the endophytic bacterial strains from Thymus altaicus and Salvia deserta possess both plant growth-promoting and anti-fungal properties,making them promising candidates for future development as growth-promoting agents and biocontrol tools for plant diseases.展开更多
[ Objective] The paper was to explore the relationship between SOD activity and resistance of corn against Setosphaeria turcica. [ Method] Strain YC and 01-23T of S. turcica with different pathogenicity were inoculate...[ Objective] The paper was to explore the relationship between SOD activity and resistance of corn against Setosphaeria turcica. [ Method] Strain YC and 01-23T of S. turcica with different pathogenicity were inoculated into corn leaves by fungal disc inoculation method, and the dynamic changes of SOD activity in infected corn leaves was measured. [Result] After inoculation of higly virulent strain YC and weakly virulent strain 01-23T of S. turcica, SOD activity in corn leaves within 1 -5 d showed obvious stages, which gradually decreased within 1 -3 d, then gradually increased within 3 -4 d, and decreased again within 4 -5 d. The SOD activity of corn leaves in inoculation treatment was higher than that in the treatment without inoculation within 1 - 4 d, which significantly decreased at fifth day. The pathogen with different pathogenicity would lead to different changes in SOD activity of corn leaves. SOD activity of corn leaves infected by weakly virulent strain 01-23T for the first day was extremely higher than that infected by strong virulent strain YC, but had no significant difference with highly virulent strain YC at 2 -3 d. [ Conclusion] SOD activity played an important role in initial resistant ability of corn against pathogen infection, and had no significant effect on resistance against pathogen extension after incidence.展开更多
The antifungal activity and toxicity of new type polyene macrolide antibiotics-Antifungalmycin 702 and Fungichromin against Rhizoctonia solani, Hel- minthosporium sigmoideum Car. , Magnaporthe grisea and Ustilaginoide...The antifungal activity and toxicity of new type polyene macrolide antibiotics-Antifungalmycin 702 and Fungichromin against Rhizoctonia solani, Hel- minthosporium sigmoideum Car. , Magnaporthe grisea and Ustilaginoidea virens were studied by mycelial growth rate method and mycelial dry weight method in vitro. The results showed that both of Antifungalmycin 702 and Fungichromin had strong antifungal activity against four speices of rice pathogenic fungi. Treated with 50 μmL Antifungalmycin 702 , the inhibitory rates of Antifungalmycin 702 agmnst R. solani, H. sigmoideum Cav., M. grisea and U. virens were 100%, 100%,91.20% and 68.10%, and EC50 and ECho were 7.00, 10.30, 14.41, 26.71 and 13.20, 17.66, 27.67,128.28 p.g/mL, respectively. Treated with 13 pg/mL Fungichremln, the inhibitory rates of Fungichromin against four speices of rice pathogenic fungi were 78.20%, 100%, 100% and 79.17%, and ECs0 and ECg0 were 1.47, 1.91, 2.37, 0. 20 and 41. （15, 3.92, 4.34, 135.54 gg/mL, respectively. The antifungal activity of Fungichromin was stronger than Antifungalmycin 702.展开更多
[ Objectives] As a traditional inoculation method of rice sheath blight, rice relative lesion height method needs rice grow to late tillering or heading stage and then inoculate in vivo, which is time-consuming and is...[ Objectives] As a traditional inoculation method of rice sheath blight, rice relative lesion height method needs rice grow to late tillering or heading stage and then inoculate in vivo, which is time-consuming and is difficult to control the testing conditions, so it is urgent to search a better alternative method. [ Methods] With rice relative lesion height method （ in vivo inoculation） as the control, the pathogenicity and crude toxin activity of Rhizoctonia solani were determined by rice detached leaf sheath method and rice detached leaf method, to compare the correlation of in vivo and in vitro inoculation. [Results] Rice detached leaf method and rice detached leaf sheath method had significantly positive correlation with rice relative lesion height method, and the determination results of rice detached leaf method and rice detached leaf sheath method could reflect the pathogenicity and crude toxin activity of R. solani accurately. [ Conclusions] Rice detached leaf method and rice detached leaf sheath method are easy to operate and control testing conditions, and could be used as alternative methods to determine pathogenicity and etude toxin activity of R. solani.展开更多
Jambul (Syzygium cumini) contain several biological activities including anti diabetic, anti-inflammatory, gastroprotective and antibacterial activity. In this study, we investigated antibacterial activity of Jambul j...Jambul (Syzygium cumini) contain several biological activities including anti diabetic, anti-inflammatory, gastroprotective and antibacterial activity. In this study, we investigated antibacterial activity of Jambul juice extract against some common enteric pathogens like Salmonella typhimurium, Shigella flexneri, Staphylococcus aureus, and ETEC (Entero toxigenic E. coli). Growth inhibition of these entero pathogenic bacteria was measured by growing in Nutrient Broth media supplemented with 0%, 5%, 10% and 25% juice extract and then plating on Nutrient Agar plate for colony count at 0, 24 and 48 hours time points. The effect of Jambul juice on the growth of Lactobacillus acidophilus and Lactobacillus bulgaricus were also investigated. We observed that the growth of Salmonella typhimurium, Shigella flexneri, Staphylococcus aureus, and ETEC were significantly inhibited by Jambul juice by 1 to 6 logs (p Lactobacillus acidophilus and Lactobacillus bulgaricus) were not affected significantly. These findings indicate that Jambul juice have selective bactericidal effects against several enteric pathogens while beneficial species remain unaffected. To far our knowledge, this is the first report about the antibacterial activity of fruit juice in Bangladesh.展开更多
Objective:To assess the antibacterial activity of 5 selected plants against 4 pathogenic bacteria.Methods:Three solvents with different polarities were used to extract antimicrobial agents from the plants via macerati...Objective:To assess the antibacterial activity of 5 selected plants against 4 pathogenic bacteria.Methods:Three solvents with different polarities were used to extract antimicrobial agents from the plants via maceration technique.The agar-disc diffusion technique was adopted to primarily screen antibacterial activities.Broth-dilution assay was employed to determine the minimum inhibitory concentration(MIC)and the minimum bactericidal concentration(MBC).Results:Among all extracts,the ethanol extract of Piper betle Linn showed the highest antibacterial activity against Gram-positive and the negative bacteria.MIC and MBC of the ethanol extract of Piper betle Linn against Salmonella typhimurium were the same(1?562.50 mg/L);while it showed the highest MIC and MBC against Pseudomonas aeruginosa of 6?250 mg/L and 12?500 mg/L,respectively.Conclusions:Salmonella typhimurium is the most susceptible bacteria while Pseudomonas aeruginosa is the most resistant bacteria towards the ethanol extract of Piper betle Linn.Piper betle possesses compounds with potential antibacterial activity and might be useful as an alternative to control infectious diseases.展开更多
Objective：To explore a new natural antibiotic. Methods：The chemical composition of the essential oil from Ganodermajaponicum （G. japonicum）mycelia was analyzed by gas chromatography-mass spectrometry（GC-MS）, The...Objective：To explore a new natural antibiotic. Methods：The chemical composition of the essential oil from Ganodermajaponicum （G. japonicum）mycelia was analyzed by gas chromatography-mass spectrometry（GC-MS）, The antimicrobial activity of the oil was evaluated against eighteen microorganisms, including bacteria, mildew and yeast by using a disc diffusion method. Furthermore, the minimum inhibitory concentrations（MIC） and the minimum bactericidal concentrations（MBC） of the essential oil against twelve clinical pathogens were determined. Results：The main components of the oil were nerolidol, decadienal, linalool and benzyl alcohol. The antimicrobial results indicated that the oil inhibited all the tested bacterium, especially Methicillin-resistant Staphylococcus aureus （MRSA） in which the antibacterial activity exhibited a MBC of 1.03 mg/ml. Conclusion： The essential oil of G. japonicum mycelium has significant inhibitory activity. It is a potential medicinal resource that can be used as a natural antibiotic.展开更多
With the development of aquaculture, there is an urgent demand for an alternative antibacterial agent to reduce the drug resistance and environmental pollution caused by the abuse of antibiotics. Recently, silver nano...With the development of aquaculture, there is an urgent demand for an alternative antibacterial agent to reduce the drug resistance and environmental pollution caused by the abuse of antibiotics. Recently, silver nanoparticles（Ag NPs） have been viewed as a novel type of antimicrobial agents due to their unique advantages. In this study,Ag NPs were biosynthesized with the ginger rhizomes extract. The biosynthesized Ag NPs were characterised by UV–visible spectroscopy, transmission electron microscopy, X-ray diffraction and fourier transform infrared spectroscopy. Furthermore, the antimicrobial activities of the Ag NPs were fully analyzed against six typical aquatic pathogens. The results indicated that the components in ginger extract could function as the chemical reductant to synthesize Ag NPs. Moreover, compared with the Ag NPs synthesized by chemical methods, the biosynthesized Ag NPs were smaller, and had higher stability and antibacterial activity. Therefore, the biosynthesized Ag NPs using ginger extract may have prospective applications in aquaculture.展开更多
A bacterial field isolate recovered from infected tomato plants in a green-house at Sidi Rehal, a region near Casablanca city (Morocco), was identified as the gammaproteobacterium Pseudomonas syringae pv. tomato DC300...A bacterial field isolate recovered from infected tomato plants in a green-house at Sidi Rehal, a region near Casablanca city (Morocco), was identified as the gammaproteobacterium Pseudomonas syringae pv. tomato DC3000 strain, the causal agent of bacterial speck. The bacterial isolate was characterized by morphological, biochemical and molecular biological tests, its growth curves carried out in various culture media, and its phytopathogenicity verified by infection tests. A screening was performed to evaluate the antibacterial activity of methanolic extracts of 12 selected Moroccan plants against the P. syringae pv. tomato DC3000 isolate, and Agar-well diffusion and Broth microdilution methods were used to determine minimum inhibitory and minimum bactericidal concentrations. Among the methanolic extracts tested, only those of Nigella sativa, Geranuim robertianum, Aizoon canariense and Rubia peregrine showed clear inhibitory and bactericidal activities, although the highest values were achieved with N. sativa, a plant used in Morocco as a spice, condiment and medicinal treatment.展开更多
Importance of urease activity on pathogenic differences among Brucella species was evaluated. In cell-free extracts, the B. suis urease showed 12 times greater specific activity than the B. melitensis urease. When Fis...Importance of urease activity on pathogenic differences among Brucella species was evaluated. In cell-free extracts, the B. suis urease showed 12 times greater specific activity than the B. melitensis urease. When Fisher-344 rats were inoculated intraperitoneally (IP), at 1 week post-inoculation (PI), B. melitensis wild type 16 M was recovered from spleens and livers in greater numbers than B. suis wild type 1330. At 8 weeks PI, spleens were clear of B. melitensis, whereas B. suis remained. The wild type and the urease deficient strains of B. suis did not differ from each other in terms of recovery from spleen or liver. Our observations suggest that B. melitensis induces greater acute infectivity in Fisher-344 rats, whereas B. suis causes chronic infectivity;and urease activity has no influence on Brucella infection using an IP route.展开更多
The economic losses and the health hazards of the mycotoxins produced by spoilage fungi are the main concerns of the food industry. The spoilage of bakery products by fungi is more common in countries with a high humi...The economic losses and the health hazards of the mycotoxins produced by spoilage fungi are the main concerns of the food industry. The spoilage of bakery products by fungi is more common in countries with a high humidity and temperature. About 5-10% of food production is spoiled by the growth of yeast and fungi in food materials. Similarly, in Western Europe, the growth of the spoilage fungi of bread is estimated to reach more than 200 million Euros per year. The history conditions of the food can be a major factor in determining any fungal spoilage--for example, stored and processed foods are more sensitive to spoilage when compared with fresh and prepared foods. Lactic acid bacteria isolated from Bulgarian wheat and rye flour were used in the present study to check their antifungal properties against pathogenic yeast and fungi imperfecta using standard disc diffusion method in vitro. A broad spectrum of antifungal activity of the six newly identified as L. plantarum strains e Tsl, Ts2, Ts3,Ts4 and Ts5, and L. helveticus Ts6 was estimated. Our in vitro studies were performed with wheat and rye sourdough, in order to simulate a real product and to assess the bio-protective potential of the tested lactobacilli. The used test-cultures are representatives of carcinogenic, toxigenic, deteriorative and allergenic fungi from the genera .4spergillus and Penicillium. The all tested strains completely suppress the growth of against C. glabrata 72. Strains L. plantarum Tsl and Ts3 completely suppress the growth against S. cerevisae. While, in the sample with L. plantarum strains e Tsl, Ts2, Ts3,Ts4 and Ts5, and L. helveticus Ts6, a retarded and weak growth of A. niger and P. claviforme was observed. However, the spore germination and the colony growth started only on the fifth day of the mould lactobacilli co-cultivation, which also should be considered as a good result. In this study six isolates Tsl,Ts2, Ts3, Ts4, Ts5 and Ts6, from the traditional Bulgarian wheat and rye flour have been identified as L. plantarum and L. helveticus and characterized as cultures with promising antifungal activity. Obtained results from the combined molecular identification （16S rRNA gene sequencing） approach contribute to give new data on the microbial biodiversity of this not well-studied niche. The antifungal activity of our new isolates, identified as L. plantarum and L. helveticus, seems to be a promising advantage of these six strains, suggesting their potential applications in different food technologies. However, more experiments have to be conducted to clarify the nature and the mechanisms of the reported antifungal activity and they are still in progress. The combination of dairy origin and strong inhibitory activity of the lactobacillus strains is a prerequisite for their possible application as starters and/or bioprotective antifungal adjuncts.展开更多
Searching alternative feed antibiotics is always a study hotspot in the field of animal production. In this study, the antipathogenic activities and probiotics stimulatory effects of 30 kinds of herbs were screened th...Searching alternative feed antibiotics is always a study hotspot in the field of animal production. In this study, the antipathogenic activities and probiotics stimulatory effects of 30 kinds of herbs were screened through Oxford cup method and Hungate roll method. 15 herbs showed significantly antibacterial activities（P〈0.05） against Escherichia coli, Salmonella enteritidis, Salmonella typhimurium and Staphylococcus aureus. Seven herbs showed greatly stimulatory promoting effects on Lactobacillus acidophilus and Bifidobacterium longum. Finally, five herbs were combined for the developed formulation with selective antibacterial properties and they were Mume Fructus（35%）, Isatidis Folium（25%）, Moslae Herba（20%）, Chrysanthemi Indici Flos（13%） and Bupleuri Radix（7%）. The herbal formulation showed significantly antibacterial abilities against four pathogens and stimulatory promoting abilities on two probiotics in vitro and the equivalent activities in broiler chickens in vivo against E. coli and L. acidophilus. The toxicity study showed it had no toxicity, which indicated that it would be a kind of preferred candidate for an alternative antibiotic in future animal production.展开更多
Bovine mastitis affects the udder health and thus causing significant economic losses. Probiotic products based on the use of lactic acid bacteria (LAB) to limit pathogens multiplication and pre-infection risks can be...Bovine mastitis affects the udder health and thus causing significant economic losses. Probiotic products based on the use of lactic acid bacteria (LAB) to limit pathogens multiplication and pre-infection risks can be an interesting alternative to post infection allopathic treatment with antibiotics. Lactococcus lactis is one of the most important bacteria used in dairy technology. In this work, a total of 21 Lactococcus lactis subsp. Lactis strains, 20 from goat milk whey and one strain from cow milk were used to evaluate their antibacterial activity against four pathogenic germs responsible for mastitis: Escherichia coli, Staphylococcus aureus, Streptococcus uberis and Streptococcus agalactiae. The nisin-producing cow milk strain was active against St. uberis and Str. Agalactiae using the well diffusion method. For the strains isolated from goat milk whey, no antimicrobial effect was observed against these pathogens. However, a different approach based on the growth of pathogenic bacteria interacting with the Lactococcus lactis strains in a minimum medium was used to study the barrier effect of LAB. The Lactococcus lactis strains S1 and S2 from goat milk whey depleted the growth of Sa. aureus, St. uberis and E. coli during 8 h and stopped the development of St. agalactiae.展开更多
文摘Objective:To access the in vitro antibacterial activity of Hibiscus rosa-sinensis(H.rosa-sinensis) flower extract against human pathogens.Methods:Antibacterial activity was evaluated by using disc and agar diffusion methods.The protein was run through poly acrylmide gel electrophoresis to view their protein profile.Results:The results showed that the cold extraction illustrates a maximum zone of inhibition against Bacillus suhtillis(B.suhtillis),Escherichia coli(E.coli) viz.,(17.00±2.91),(14.50±1.71)mm.followed by hot extraction against.E.coli.Salmonella sp.as(11.66 ±3.14),(10.60±3.09)mm.In methanol extraction showed a highest zone of inhibition recorded against B.suhtillis,E.coli as(18.86±0.18),(18.00±1.63) mm pursued by ethanol extraction shower) utmost zone of inhibition recorded against Salmonella sp.at(20.40±1.54) mm.The crude protein from flower showed a maximum inhibitory zone observed against Salmonella sp.,E.coli viz.,(16.55±1.16),(14.30±2.86)mm.The flower material can be taken as an alternative source of antibacterial agent against the human pathogens.Conclusions:The extracts of the H.rosasinensis art;proved to have potential antibacterial activity,further studies arc highly need for the drug development.
文摘Objective:To investigate in vitro and in vivo antibacterial potentials of Vitex negundo(V. negundo) leaf extracts against diverse enteric pathogens.Methods:Water and methanol extracts of V.negundo leaves were evaluated against enteric bacterial pathogens by using standard disc diffusion,viable bacterial cell count methods,determination of minimum inhibitory concentrations(MIC) and minimum bactericidal concentrations(MBC).Results:Methanol extract of V.negundo leaves showed potent antibacterial activity(inhibition zone:9.9-22.6 mm,MIC: 200-3 200μg/mL.MBC:200-6 400μg/mL) against all the pathogenic enteric bacteria(Vibrio cholerae.Vibrio parahemolyticus.Vibrio mimicus.Echerichia coli,Shigella spps.,and Aeromonas spps) tested.Methanol extract of V.negundo leaves showed potent bactericidal activity both in vitro laboratory conditions(MBC,200-400μg/mL) and in the intestinal environment(Dose,1-2 mg/mL) of infant mice against pathogenic Vibrio cholerae,the major causative agent of cholera. Furthermore,assays using the mice cholera model showed that V.negundo methanol extract can protect mice from Vibrio cholerae infection and significandy decrease the mortality rate(P【0.0001). Conclusions:For the first time we showed thal medianol extract of V.negundo leaves exhibited strong vihriocidal activity both in vitro and in vivo conditions.Therefore,it will he useful to identify and isolate the active compounds of this extract that could be a good alternative of antibiotics to treat cholera.
文摘Objective:To investigate in vitro and in vivo antibacterial potentials of Vitex negundo(V. negundo) leaf extracts against diverse enteric pathogens.Methods:Water and methanol extracts of V.negundo leaves were evaluated against enteric bacterial pathogens by using standard disc diffusion,viable bacterial cell count methods,determination of minimum inhibitory concentrations(MIC) and minimum bactericidal concentrations(MBC).Results:Methanol extract of V.negundo leaves showed potent antibacterial activity(inhibition zone:9.9- 22.6 mm,MIC: 200-3 200μg/mL,MBC:200-6 400μg/mL) against all the pathogenic enleric bacteria(Vibrio cholerae,Vibrio parahaemolyticus,Vibrio mimicus,Echerichia coli.Shigella spps.,and Aeromonas spps) tested.Methanol extract of V.negundo leaves showed potent bactericidal activity both in vitro laboratory conditions(MBC,200-400μg/mL) and in the intestinal environment(Dose,1-2 mg/mL) of infant mice against pathogenic Vibrio cholerae,the major causative agent of cholera. Furthermore,assays using the mice cholera model showed that V.negundo methanol extract can protect mice from Vibrio cholerae infection and significantly decrease the mortality rate(P【0.0001).Conclusioas:For the first time we showed that methanol extract of V.negundo leaves exhibited strong vibriocidal activity both in vitro and in vivo conditions.Therefore,it will be useful to identify and isolate the active compounds of this extract that could be a good alternative of antibiotics to treat cholera.
文摘Five wild plant species belonging to different families (Chenopodium album, Plantago major, Elytrigia elongata, Filipendula ulmaria and Nigella sativa) widely spread in Russian Federation and the former USSR were evaluated for their ability to inhibit growth of two important human food-borne pathogens (Escherichia coli O157:H7 and Listeria monocytogenes strain EGD-e) and eight plant pathogens (Alternaria alternata, Alternaria tenuissima, Bipolaris sorokiniana, Stagonospora nodorum, Fusarium solani, Fusarium oxysporum, Fusarium culmorum and Phytophtora infestans). To isolate biologically active compounds from seeds, a step-wise procedure including extraction with hexane, ethyl acetate, ethanol, and 10% acetic acid followed by reversed-phase HPLC was developed. Using disc-diffusion assay, the highest activity against E. coli O157:H7 was observed with extracts from F. ulmaria (hexane and ethyl acetate extracts and the unbound RP-HPLC fraction) and P. major (ethyl acetate extract and the unbound RP-HPLC fraction);E. elongate (the unbound RP-HPLC fraction) was less active. The extracts from P. major and E. elongate (the unbound RP-HPLC fractions) were equally highly active against L. monocytogenes, while those of F. ulmaria (the unbound RP-HPLC fraction) and N. sativa (hexane and ethyl acetate extracts) were less active against this pathogen. The dynamics of L. monocytogenes EGD-е and E. coli O157:H7 growth in the presence of two most potent extracts (RP-HPLC-unbound fractions of P. major and E. elongate and the hexane extract of F. ulmaria) was studied.
文摘The study aimed to evaluate the endophytic fungi isolated from <em>Cocos nucifera</em> (L.) cotyledon for their possible antimicrobial activity. A total of twelve endophytic fungal species were successfully isolated, from which five were selected and presumptively identified, including <em>Aspergillus niger</em>, <em>Raffaelea sp.</em>, <em>Aspergillus flavus</em>, <em>Cladosporium sp.</em> and <em>Pseudallescheria spp.</em> based on their macro and microscopic characters. The agar blocks of actively growing pure culture were assessed for antibacterial activity against five human pathogenic bacterial and fungal strains: <em>Escherichia coli</em> (BIOTECH 1634), <em>Bacillus subtilis</em> (BIOTECH 1697), <em>Staphylococcus aureus</em> (BIOTECH 1592), <em>Serratia marcescens</em> (BIOTECH 1748), and <em>Candida tropicalis</em> (BIOTECH 2085). Among the selected five endophytic used for antimicrobial activity screening, the <em>Raffaelea sp.</em> (CN-EF 2) has shown a high zone of inhibition of 11 mm against <em>Bacillus subtilis</em>, 18 mm against <em>Escherichia coli</em>, 15 mm against <em>Staphylococcus aureus</em>, and 11 mm against <em>Candida tropicalis</em>. Correspondingly, <em>Aspergillus niger</em> (CN-EF 1) has shown a zone of inhibition of 16 mm against <em>C. tropicalis</em>. The endophytic fungus <em>Raffaelea sp.</em> was effective against all test organisms except for <em>Serratia marcescens</em>, while <em>Aspergillus niger</em> was only effective for pathogenic fungi <em>C. albicans</em>. Hence, further in-depth studies of the isolated endophytic fungi are needed to determine the mechanisms behind the endophytes’ inhibitory effects.
基金financially supported by SERC Fast Track OYSSchem,Department of Science and Technology(DST),New Delhi,India[grant No.304/2004(SR/FT/L-129/2004)]
文摘Objective:To investigate antibacterial potential of Trifolium alexandrinum(T.alexandrinum) Linn,against seven gram positive and eleven gram negative hospital isolated human pathogenic bacterial strains responsible for many tropical diseases.Methods:Non-polar and polar extracts of the leaves of T.alexandrinum i.e.,hexane,dichloromethane(DCM),ethyl acetate(EtOAc), methanol(MeOH) and aqueous(AQ) extracts at five different concentrations(1,2,5,10 and 15 mg/ mL) were prepared to evaluate their antibacterial value.NCCL standards were strictly followed to perform antimicrobial disc susceptibility test using disc diffusion method.Results:Polar extracts demonstrated significant antibacterial activity against tested pathogens.EtOAc and MeOH extracts showed maximum antibacterial activity with higher inhibition zone and were found effective against seventeen of the tested pathogens.While AQ plant extract inhibited the growth of sixteen of the test strains.EtOAc and MeOH plant extracts inhibited the growth of all seven gram positive and ten of the gram negative bacterial strains.Conclusions:The present study strongly confirms the effectiveness of crude leaves extracts against tested human pathogenic bacterial strains causing several tropical diseases.Since Egyptian clover is used as a fodder plant,it could be helpful in controlling various infectious diseases associated with cattle as well.
基金supported by the Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources (Guangxi Normal University,China),Ministry of Education of China (07109001-11)Guangxi Natural Science Fund Project,China (0991097)
文摘Acorus tatarinowii Schott is a traditional Chinese medicine plant and has multiple bioactivities in medicine and pesticide field. In this study, the antifungal compound 1,2-dimethoxy-4（2-propenyl） benzene was isolated from A. tatarinowii Schott by activity-directed isolation method, and the inhibitory activity of the extract and 1,2-dimethoxy-4（2-propenyl） benzene against seven plant pathogenic fungi was evaluated. The results showed that the extract and 1,2-dimethoxy-4（2- propenyl） benzene had high inhibitory activity against hyphal growth of Thielaviopsis paradoxa （de Seynes） V. Hohnel, Pestalotia mangiferae P. Henn., Fusarium oxysporum f. sp. niveum （E. F. Smith） Syn. et Hans., Alternaria alternate Tanaka, Colletotrichum musae （Berk et Curt） V. Arx, Sphaceloma fawcettii Jenk., and Mycosphaerella sentina （Fr.） Schroter. The EC50 values of extract were 1.6162, 1.6811, 1.1253, 3.5771, 1.7024, 2.2284, and 2.2221 g L^-1, respectively, and the EC50 values of 1,2-dimethoxy-4（2-propenyl） benzene were 0.1021, 0.0997, 0.0805, 0.1742, 0.1503, 0.1853, and 0.1924 g L^-1, respectively. 1,2-Dimethoxy-4（2-propenyl） benzene also inhibited spores germination of T. paradoxa （de Seynes） V. Hohnel and F. oxysporum f. sp. niveum （E. F. Smith） Syn. et Hans., with the inhibitory rates of 98.81 and 100% at a concentration of 0.4 g L^-1 after 8 h, respectively. 1,2-Dimethoxy-4（2-propenyl） benzene is a potential botanical antifungal agent for controling of plant fungal diseases.
基金financially supported by the Third Xinjiang Comprehensive Scientific Expedition (2022xjkk020605)the Xinjiang Uygur Autonomous Region Regional Coordinated Innovation Project (Shanghai Cooperation Organization Science and Technology Partnership Program) (2020E01047)supported by the Introduction Project of High-level Talents in Xinjiang Uygur Autonomous Region, China
文摘Endophytes,as crucial components of plant microbial communities,significantly contribute to enhancing the absorption of nutrients such as nitrogen and phosphorus by their hosts,promote plant growth,and degrade pathogenic fungal mycelia.In this study,an experiment was conducted in August 2022 to explore the growth-promoting potential of endophytic bacterial strains isolated from two medical plant species,Thymus altaicus and Salvia deserta,using a series of screening media.Plant samples of Thymus altaicus and Salvia deserta were collected from Zhaosu County and Habahe County in Xinjiang Uygur Autonomous Region,China,in July 2021.Additionally,the inhibitory effects of endophytic bacterial strains on the four pathogenic fungi(Fusarium oxysporum,Fulvia fulva,Alternaria solani,and Valsa mali)were determined through the plate confrontation method.A total of 80 endophytic bacterial strains were isolated from Thymus altaicus,while a total of 60 endophytic bacterial strains were isolated from Salvia deserta.The endophytic bacterial strains from both Thymus altaicus and Salvia deserta exhibited plant growth-promoting properties.Specifically,the strains of Bacillus sp.TR002,Bacillus sp.TR005,Microbacterium sp.TSB5,and Rhodococcus sp.TR013 demonstrated strong cellulase-producing activity,siderophore-producing activity,phosphate solubilization activity,and nitrogen-fixing activity,respectively.Out of 140 endophytic bacterial strains isolated from Thymus altaicus and Salvia deserta,104 strains displayed anti-fungal activity against Fulvia fulva,Alternaria solani,Fusarium oxysporum,and Valsa mali.Furthermore,the strains of Bacillus sp.TR005,Bacillus sp.TS003,and Bacillus sp.TSB7 exhibited robust inhibition rates against all the four pathogenic fungi.In conclusion,the endophytic bacterial strains from Thymus altaicus and Salvia deserta possess both plant growth-promoting and anti-fungal properties,making them promising candidates for future development as growth-promoting agents and biocontrol tools for plant diseases.
基金Supported by Natural Science Foundation of Hebei Province( C2010001854 )Projects of Tangshan Science and Technology Bureau(10120201A-7)
文摘[ Objective] The paper was to explore the relationship between SOD activity and resistance of corn against Setosphaeria turcica. [ Method] Strain YC and 01-23T of S. turcica with different pathogenicity were inoculated into corn leaves by fungal disc inoculation method, and the dynamic changes of SOD activity in infected corn leaves was measured. [Result] After inoculation of higly virulent strain YC and weakly virulent strain 01-23T of S. turcica, SOD activity in corn leaves within 1 -5 d showed obvious stages, which gradually decreased within 1 -3 d, then gradually increased within 3 -4 d, and decreased again within 4 -5 d. The SOD activity of corn leaves in inoculation treatment was higher than that in the treatment without inoculation within 1 - 4 d, which significantly decreased at fifth day. The pathogen with different pathogenicity would lead to different changes in SOD activity of corn leaves. SOD activity of corn leaves infected by weakly virulent strain 01-23T for the first day was extremely higher than that infected by strong virulent strain YC, but had no significant difference with highly virulent strain YC at 2 -3 d. [ Conclusion] SOD activity played an important role in initial resistant ability of corn against pathogen infection, and had no significant effect on resistance against pathogen extension after incidence.
基金Supported by National Natural Science Foundation of China(30960011 and 31071724) Natural Science Foundation of Jiangxi Province (2009GZN0030)Science and Technology Support Program of Jiangxi Province(2007BN14002)
文摘The antifungal activity and toxicity of new type polyene macrolide antibiotics-Antifungalmycin 702 and Fungichromin against Rhizoctonia solani, Hel- minthosporium sigmoideum Car. , Magnaporthe grisea and Ustilaginoidea virens were studied by mycelial growth rate method and mycelial dry weight method in vitro. The results showed that both of Antifungalmycin 702 and Fungichromin had strong antifungal activity against four speices of rice pathogenic fungi. Treated with 50 μmL Antifungalmycin 702 , the inhibitory rates of Antifungalmycin 702 agmnst R. solani, H. sigmoideum Cav., M. grisea and U. virens were 100%, 100%,91.20% and 68.10%, and EC50 and ECho were 7.00, 10.30, 14.41, 26.71 and 13.20, 17.66, 27.67,128.28 p.g/mL, respectively. Treated with 13 pg/mL Fungichremln, the inhibitory rates of Fungichromin against four speices of rice pathogenic fungi were 78.20%, 100%, 100% and 79.17%, and ECs0 and ECg0 were 1.47, 1.91, 2.37, 0. 20 and 41. （15, 3.92, 4.34, 135.54 gg/mL, respectively. The antifungal activity of Fungichromin was stronger than Antifungalmycin 702.
基金Supported by National Natural Science Foundation of China(31160352,31360423)Science and Technology Innovation Team Support Plan for Colleges and Universities in Yunnan Province(YJK[2014]22)
文摘[ Objectives] As a traditional inoculation method of rice sheath blight, rice relative lesion height method needs rice grow to late tillering or heading stage and then inoculate in vivo, which is time-consuming and is difficult to control the testing conditions, so it is urgent to search a better alternative method. [ Methods] With rice relative lesion height method （ in vivo inoculation） as the control, the pathogenicity and crude toxin activity of Rhizoctonia solani were determined by rice detached leaf sheath method and rice detached leaf method, to compare the correlation of in vivo and in vitro inoculation. [Results] Rice detached leaf method and rice detached leaf sheath method had significantly positive correlation with rice relative lesion height method, and the determination results of rice detached leaf method and rice detached leaf sheath method could reflect the pathogenicity and crude toxin activity of R. solani accurately. [ Conclusions] Rice detached leaf method and rice detached leaf sheath method are easy to operate and control testing conditions, and could be used as alternative methods to determine pathogenicity and etude toxin activity of R. solani.
文摘Jambul (Syzygium cumini) contain several biological activities including anti diabetic, anti-inflammatory, gastroprotective and antibacterial activity. In this study, we investigated antibacterial activity of Jambul juice extract against some common enteric pathogens like Salmonella typhimurium, Shigella flexneri, Staphylococcus aureus, and ETEC (Entero toxigenic E. coli). Growth inhibition of these entero pathogenic bacteria was measured by growing in Nutrient Broth media supplemented with 0%, 5%, 10% and 25% juice extract and then plating on Nutrient Agar plate for colony count at 0, 24 and 48 hours time points. The effect of Jambul juice on the growth of Lactobacillus acidophilus and Lactobacillus bulgaricus were also investigated. We observed that the growth of Salmonella typhimurium, Shigella flexneri, Staphylococcus aureus, and ETEC were significantly inhibited by Jambul juice by 1 to 6 logs (p Lactobacillus acidophilus and Lactobacillus bulgaricus) were not affected significantly. These findings indicate that Jambul juice have selective bactericidal effects against several enteric pathogens while beneficial species remain unaffected. To far our knowledge, this is the first report about the antibacterial activity of fruit juice in Bangladesh.
基金This research was financially supported by the National Research Council of Thailand,Thailand and Kalasin University,Thailand.The authors also thanks the Department of Science and Mathematics,Faculty of Science and Health Technology and the Department of Biotechnology,Faculty of Agricultural Technology,Kalasin University for providing instruments.
文摘Objective:To assess the antibacterial activity of 5 selected plants against 4 pathogenic bacteria.Methods:Three solvents with different polarities were used to extract antimicrobial agents from the plants via maceration technique.The agar-disc diffusion technique was adopted to primarily screen antibacterial activities.Broth-dilution assay was employed to determine the minimum inhibitory concentration(MIC)and the minimum bactericidal concentration(MBC).Results:Among all extracts,the ethanol extract of Piper betle Linn showed the highest antibacterial activity against Gram-positive and the negative bacteria.MIC and MBC of the ethanol extract of Piper betle Linn against Salmonella typhimurium were the same(1?562.50 mg/L);while it showed the highest MIC and MBC against Pseudomonas aeruginosa of 6?250 mg/L and 12?500 mg/L,respectively.Conclusions:Salmonella typhimurium is the most susceptible bacteria while Pseudomonas aeruginosa is the most resistant bacteria towards the ethanol extract of Piper betle Linn.Piper betle possesses compounds with potential antibacterial activity and might be useful as an alternative to control infectious diseases.
基金supported by the Natural Science Foundation of Hubei Province(2004ABA228)
文摘Objective：To explore a new natural antibiotic. Methods：The chemical composition of the essential oil from Ganodermajaponicum （G. japonicum）mycelia was analyzed by gas chromatography-mass spectrometry（GC-MS）, The antimicrobial activity of the oil was evaluated against eighteen microorganisms, including bacteria, mildew and yeast by using a disc diffusion method. Furthermore, the minimum inhibitory concentrations（MIC） and the minimum bactericidal concentrations（MBC） of the essential oil against twelve clinical pathogens were determined. Results：The main components of the oil were nerolidol, decadienal, linalool and benzyl alcohol. The antimicrobial results indicated that the oil inhibited all the tested bacterium, especially Methicillin-resistant Staphylococcus aureus （MRSA） in which the antibacterial activity exhibited a MBC of 1.03 mg/ml. Conclusion： The essential oil of G. japonicum mycelium has significant inhibitory activity. It is a potential medicinal resource that can be used as a natural antibiotic.
基金The Scientific Research Projects of Shandong University under contract No.J15LE03the Key Research and Development Program of Shandong Province under contract No.2016GNC111016the Key Research and Developement Program of Yantai under contract No.2016ZH059
文摘With the development of aquaculture, there is an urgent demand for an alternative antibacterial agent to reduce the drug resistance and environmental pollution caused by the abuse of antibiotics. Recently, silver nanoparticles（Ag NPs） have been viewed as a novel type of antimicrobial agents due to their unique advantages. In this study,Ag NPs were biosynthesized with the ginger rhizomes extract. The biosynthesized Ag NPs were characterised by UV–visible spectroscopy, transmission electron microscopy, X-ray diffraction and fourier transform infrared spectroscopy. Furthermore, the antimicrobial activities of the Ag NPs were fully analyzed against six typical aquatic pathogens. The results indicated that the components in ginger extract could function as the chemical reductant to synthesize Ag NPs. Moreover, compared with the Ag NPs synthesized by chemical methods, the biosynthesized Ag NPs were smaller, and had higher stability and antibacterial activity. Therefore, the biosynthesized Ag NPs using ginger extract may have prospective applications in aquaculture.
文摘A bacterial field isolate recovered from infected tomato plants in a green-house at Sidi Rehal, a region near Casablanca city (Morocco), was identified as the gammaproteobacterium Pseudomonas syringae pv. tomato DC3000 strain, the causal agent of bacterial speck. The bacterial isolate was characterized by morphological, biochemical and molecular biological tests, its growth curves carried out in various culture media, and its phytopathogenicity verified by infection tests. A screening was performed to evaluate the antibacterial activity of methanolic extracts of 12 selected Moroccan plants against the P. syringae pv. tomato DC3000 isolate, and Agar-well diffusion and Broth microdilution methods were used to determine minimum inhibitory and minimum bactericidal concentrations. Among the methanolic extracts tested, only those of Nigella sativa, Geranuim robertianum, Aizoon canariense and Rubia peregrine showed clear inhibitory and bactericidal activities, although the highest values were achieved with N. sativa, a plant used in Morocco as a spice, condiment and medicinal treatment.
文摘Importance of urease activity on pathogenic differences among Brucella species was evaluated. In cell-free extracts, the B. suis urease showed 12 times greater specific activity than the B. melitensis urease. When Fisher-344 rats were inoculated intraperitoneally (IP), at 1 week post-inoculation (PI), B. melitensis wild type 16 M was recovered from spleens and livers in greater numbers than B. suis wild type 1330. At 8 weeks PI, spleens were clear of B. melitensis, whereas B. suis remained. The wild type and the urease deficient strains of B. suis did not differ from each other in terms of recovery from spleen or liver. Our observations suggest that B. melitensis induces greater acute infectivity in Fisher-344 rats, whereas B. suis causes chronic infectivity;and urease activity has no influence on Brucella infection using an IP route.
文摘The economic losses and the health hazards of the mycotoxins produced by spoilage fungi are the main concerns of the food industry. The spoilage of bakery products by fungi is more common in countries with a high humidity and temperature. About 5-10% of food production is spoiled by the growth of yeast and fungi in food materials. Similarly, in Western Europe, the growth of the spoilage fungi of bread is estimated to reach more than 200 million Euros per year. The history conditions of the food can be a major factor in determining any fungal spoilage--for example, stored and processed foods are more sensitive to spoilage when compared with fresh and prepared foods. Lactic acid bacteria isolated from Bulgarian wheat and rye flour were used in the present study to check their antifungal properties against pathogenic yeast and fungi imperfecta using standard disc diffusion method in vitro. A broad spectrum of antifungal activity of the six newly identified as L. plantarum strains e Tsl, Ts2, Ts3,Ts4 and Ts5, and L. helveticus Ts6 was estimated. Our in vitro studies were performed with wheat and rye sourdough, in order to simulate a real product and to assess the bio-protective potential of the tested lactobacilli. The used test-cultures are representatives of carcinogenic, toxigenic, deteriorative and allergenic fungi from the genera .4spergillus and Penicillium. The all tested strains completely suppress the growth of against C. glabrata 72. Strains L. plantarum Tsl and Ts3 completely suppress the growth against S. cerevisae. While, in the sample with L. plantarum strains e Tsl, Ts2, Ts3,Ts4 and Ts5, and L. helveticus Ts6, a retarded and weak growth of A. niger and P. claviforme was observed. However, the spore germination and the colony growth started only on the fifth day of the mould lactobacilli co-cultivation, which also should be considered as a good result. In this study six isolates Tsl,Ts2, Ts3, Ts4, Ts5 and Ts6, from the traditional Bulgarian wheat and rye flour have been identified as L. plantarum and L. helveticus and characterized as cultures with promising antifungal activity. Obtained results from the combined molecular identification （16S rRNA gene sequencing） approach contribute to give new data on the microbial biodiversity of this not well-studied niche. The antifungal activity of our new isolates, identified as L. plantarum and L. helveticus, seems to be a promising advantage of these six strains, suggesting their potential applications in different food technologies. However, more experiments have to be conducted to clarify the nature and the mechanisms of the reported antifungal activity and they are still in progress. The combination of dairy origin and strong inhibitory activity of the lactobacillus strains is a prerequisite for their possible application as starters and/or bioprotective antifungal adjuncts.
基金supported by Hebei Science and Technology Support Program of China (13226602D)
文摘Searching alternative feed antibiotics is always a study hotspot in the field of animal production. In this study, the antipathogenic activities and probiotics stimulatory effects of 30 kinds of herbs were screened through Oxford cup method and Hungate roll method. 15 herbs showed significantly antibacterial activities（P〈0.05） against Escherichia coli, Salmonella enteritidis, Salmonella typhimurium and Staphylococcus aureus. Seven herbs showed greatly stimulatory promoting effects on Lactobacillus acidophilus and Bifidobacterium longum. Finally, five herbs were combined for the developed formulation with selective antibacterial properties and they were Mume Fructus（35%）, Isatidis Folium（25%）, Moslae Herba（20%）, Chrysanthemi Indici Flos（13%） and Bupleuri Radix（7%）. The herbal formulation showed significantly antibacterial abilities against four pathogens and stimulatory promoting abilities on two probiotics in vitro and the equivalent activities in broiler chickens in vivo against E. coli and L. acidophilus. The toxicity study showed it had no toxicity, which indicated that it would be a kind of preferred candidate for an alternative antibiotic in future animal production.
文摘Bovine mastitis affects the udder health and thus causing significant economic losses. Probiotic products based on the use of lactic acid bacteria (LAB) to limit pathogens multiplication and pre-infection risks can be an interesting alternative to post infection allopathic treatment with antibiotics. Lactococcus lactis is one of the most important bacteria used in dairy technology. In this work, a total of 21 Lactococcus lactis subsp. Lactis strains, 20 from goat milk whey and one strain from cow milk were used to evaluate their antibacterial activity against four pathogenic germs responsible for mastitis: Escherichia coli, Staphylococcus aureus, Streptococcus uberis and Streptococcus agalactiae. The nisin-producing cow milk strain was active against St. uberis and Str. Agalactiae using the well diffusion method. For the strains isolated from goat milk whey, no antimicrobial effect was observed against these pathogens. However, a different approach based on the growth of pathogenic bacteria interacting with the Lactococcus lactis strains in a minimum medium was used to study the barrier effect of LAB. The Lactococcus lactis strains S1 and S2 from goat milk whey depleted the growth of Sa. aureus, St. uberis and E. coli during 8 h and stopped the development of St. agalactiae.
