从生姜连作地土壤中分离到1株对生姜青枯假单胞杆菌(Pseudomonas solanacarum Smith)有强拮抗作用的沙雷氏菌株R11,对该菌株进行了形态特征、培养特征、生理生化和16S r DNA序列分析的系统鉴定,发现R11为革兰氏阴性菌,端生一根鞭毛。以1...从生姜连作地土壤中分离到1株对生姜青枯假单胞杆菌(Pseudomonas solanacarum Smith)有强拮抗作用的沙雷氏菌株R11,对该菌株进行了形态特征、培养特征、生理生化和16S r DNA序列分析的系统鉴定,发现R11为革兰氏阴性菌,端生一根鞭毛。以16S r DNA序列为基础构建了包括11株相关种属细菌在内的系统发育树,R11与沙雷氏菌(Serratia sp.)十分接近,序列相似性值达99%。展开更多
At least 20-40% of annual losses of avocado crops are caused by pathogenic fungi.The chemical treatments of these diseases are inefficient,cause environmental pollution and are increasingly restricted by international...At least 20-40% of annual losses of avocado crops are caused by pathogenic fungi.The chemical treatments of these diseases are inefficient,cause environmental pollution and are increasingly restricted by international laws.This work aimed to assess the biocontrol capacity of a bacterial extract to protect avocado fruits and plants from pathogen infections.Extracts from the bacterial isolate Serratia sp.ARP5.1 were obtained from liquid fermentations in a biorreactor.A body rot postharvest infection model with Colletotrichum gloeosporioides on fruits was developed.Moreover,packaging conditions were simulated using the bacterial extract and the commercial fungicide prochloraz as a positive control.Additionally,seedlings infections with Phytophthora cinnamomi were performed on two types of avocado(West Indian race and cv.Hass).The Area Under Disease Progress Curve(AUDPC) was recorded using the bacterial extract and a commercial product with fosetyl-aluminium as treatments.The bacterial extract significantly reduced infections by C.gloeosporioides on injured avocado fruits at 31.1 μg mL^-1.Intact fruits were also protected against body rot infections at the same concentration and showed no significant differences with the commercial fungicide.On the other hand,AUDPC in the seedlings was significantly reduced with the extract treatment at 3 μg mL^-1 compared to the control.However,a possible phytotoxicity effect of the extract was evidenced in the seedlings and confirmed by pathogen recovery and tests on Raphanus sativus seedlings.Finally,formulations of the extracts(emulsion and emulsifiable concentrate) were prepared,and bioactive stability was assessed for 8 wk.The emulsion formulates demonstrated very stable bioactivity against P.cinnamomi.The extract and the emulsion formulate showed promising results for the control of avocado pathogens.New bioproducts based on this type of active principles could be developed for the benefit of avocado industry.展开更多
为加快病死猪堆肥过程中油脂的降解,从受油脂污染的样品中分离、筛选高效油脂降解菌,并将其接种至堆肥中进行堆肥效果验证。共分离得到6株具有油脂降解能力的菌株,其中菌株D-4降解能力最强。在初始筛选条件下,该菌对油脂的降解率达57.2...为加快病死猪堆肥过程中油脂的降解,从受油脂污染的样品中分离、筛选高效油脂降解菌,并将其接种至堆肥中进行堆肥效果验证。共分离得到6株具有油脂降解能力的菌株,其中菌株D-4降解能力最强。在初始筛选条件下,该菌对油脂的降解率达57.21%,在发酵48~54 h时达到产脂肪酶的高峰。经形态特征、生理生化特征、16S r DNA序列系统发育分析,将其鉴定为黏质沙雷氏菌(Serratia marcescens)。D-4菌株不同添加量的堆肥效果表明,接种D-4菌各组堆肥的油脂含量均显著(P<0.05)低于各时期对照组中的油脂含量。结果表明,筛选获得的菌株D-4为高效油脂降解菌株,可以用于病死猪腐熟堆肥,加快病死猪中油脂的降解。展开更多
This study was undertaken to determine heavy metal resistance and antibiotic susceptibility of three non-pathogenic red pigmented bacteria namely WPRA3, SM11-3j and SC-G18, isolated from marine environments of Malaysi...This study was undertaken to determine heavy metal resistance and antibiotic susceptibility of three non-pathogenic red pigmented bacteria namely WPRA3, SM11-3j and SC-G18, isolated from marine environments of Malaysia. The bacteria isolates were identified by 16S rRNA sequencing and by biochemical and morphological tests. The 16S rRNA gene sequences of all isolates showed ≥96% similarity to Serratia spp. Antibiotic susceptibility test of isolates was assayed according to the Kirby-Bauer disc diffusion method. All isolates were highly resistant to beta-lactam antibiotics, but were susceptible to quinolone antibiotics. Minimum inhibitory concentration (MIC) of nine heavy metals (Ni2+, Co2+, Cr3+, Zn2+, Mn2+, Pb2+, Hg2+, Cd2+ and Cu2+) against the bacteria isolates were determined via the plate-dilution method. The isolates exhibited resistance to Ni2+, Co2+, Cr3+ and Zn2+. Isolates WPRA3 and SM11-3j showed higher multiple tolerances to heavy metals. The results obtained indicate that bacteria from marine environments of Malaysia present interesting metabolic activities, which should be studied and explored for potential biotechnological applications.展开更多
A screening of environmental conditions that would elicit robust biofilm in a collection of Serratia marcescens isolated from soil revealed that exogenous milk protein increased biofilm productivity up to ten-fold. A ...A screening of environmental conditions that would elicit robust biofilm in a collection of Serratia marcescens isolated from soil revealed that exogenous milk protein increased biofilm productivity up to ten-fold. A select screening of fish pathogens, freshwater and human isolates identified several other species that responded similarly to exogenous protein. The optimal protein concentration was species specific;S. marcescens at 5% milk protein, Aeromonas sp. at 2% - 3%, Flavobacterium columnare at 1% and Pseudomonas aeruginosa at 0.1% - 0.4%. Media supplemented with milk protein also increased the cell counts in biofilm as well as the protein incorporated into the biofilm matrix. These data suggest that relatively high concentrations of exogenous protein may serve as an environmental trigger for biofilm formation, particularly for pathogenic bacteria exposed to relatively high concentrations of protein in bodily fluids and mucosal surfaces.展开更多
文摘从生姜连作地土壤中分离到1株对生姜青枯假单胞杆菌(Pseudomonas solanacarum Smith)有强拮抗作用的沙雷氏菌株R11,对该菌株进行了形态特征、培养特征、生理生化和16S r DNA序列分析的系统鉴定,发现R11为革兰氏阴性菌,端生一根鞭毛。以16S r DNA序列为基础构建了包括11株相关种属细菌在内的系统发育树,R11与沙雷氏菌(Serratia sp.)十分接近,序列相似性值达99%。
基金the Faculty of Health Sciences from the Institution University Colegio Mayor de Antioquia and the General System of Royalties from Antioquia,Colombia,for funding this projectthe National University of Colombia and the Doctoral Fellowship Program(567)from Colciencias
文摘At least 20-40% of annual losses of avocado crops are caused by pathogenic fungi.The chemical treatments of these diseases are inefficient,cause environmental pollution and are increasingly restricted by international laws.This work aimed to assess the biocontrol capacity of a bacterial extract to protect avocado fruits and plants from pathogen infections.Extracts from the bacterial isolate Serratia sp.ARP5.1 were obtained from liquid fermentations in a biorreactor.A body rot postharvest infection model with Colletotrichum gloeosporioides on fruits was developed.Moreover,packaging conditions were simulated using the bacterial extract and the commercial fungicide prochloraz as a positive control.Additionally,seedlings infections with Phytophthora cinnamomi were performed on two types of avocado(West Indian race and cv.Hass).The Area Under Disease Progress Curve(AUDPC) was recorded using the bacterial extract and a commercial product with fosetyl-aluminium as treatments.The bacterial extract significantly reduced infections by C.gloeosporioides on injured avocado fruits at 31.1 μg mL^-1.Intact fruits were also protected against body rot infections at the same concentration and showed no significant differences with the commercial fungicide.On the other hand,AUDPC in the seedlings was significantly reduced with the extract treatment at 3 μg mL^-1 compared to the control.However,a possible phytotoxicity effect of the extract was evidenced in the seedlings and confirmed by pathogen recovery and tests on Raphanus sativus seedlings.Finally,formulations of the extracts(emulsion and emulsifiable concentrate) were prepared,and bioactive stability was assessed for 8 wk.The emulsion formulates demonstrated very stable bioactivity against P.cinnamomi.The extract and the emulsion formulate showed promising results for the control of avocado pathogens.New bioproducts based on this type of active principles could be developed for the benefit of avocado industry.
文摘为加快病死猪堆肥过程中油脂的降解,从受油脂污染的样品中分离、筛选高效油脂降解菌,并将其接种至堆肥中进行堆肥效果验证。共分离得到6株具有油脂降解能力的菌株,其中菌株D-4降解能力最强。在初始筛选条件下,该菌对油脂的降解率达57.21%,在发酵48~54 h时达到产脂肪酶的高峰。经形态特征、生理生化特征、16S r DNA序列系统发育分析,将其鉴定为黏质沙雷氏菌(Serratia marcescens)。D-4菌株不同添加量的堆肥效果表明,接种D-4菌各组堆肥的油脂含量均显著(P<0.05)低于各时期对照组中的油脂含量。结果表明,筛选获得的菌株D-4为高效油脂降解菌株,可以用于病死猪腐熟堆肥,加快病死猪中油脂的降解。
文摘This study was undertaken to determine heavy metal resistance and antibiotic susceptibility of three non-pathogenic red pigmented bacteria namely WPRA3, SM11-3j and SC-G18, isolated from marine environments of Malaysia. The bacteria isolates were identified by 16S rRNA sequencing and by biochemical and morphological tests. The 16S rRNA gene sequences of all isolates showed ≥96% similarity to Serratia spp. Antibiotic susceptibility test of isolates was assayed according to the Kirby-Bauer disc diffusion method. All isolates were highly resistant to beta-lactam antibiotics, but were susceptible to quinolone antibiotics. Minimum inhibitory concentration (MIC) of nine heavy metals (Ni2+, Co2+, Cr3+, Zn2+, Mn2+, Pb2+, Hg2+, Cd2+ and Cu2+) against the bacteria isolates were determined via the plate-dilution method. The isolates exhibited resistance to Ni2+, Co2+, Cr3+ and Zn2+. Isolates WPRA3 and SM11-3j showed higher multiple tolerances to heavy metals. The results obtained indicate that bacteria from marine environments of Malaysia present interesting metabolic activities, which should be studied and explored for potential biotechnological applications.
文摘A screening of environmental conditions that would elicit robust biofilm in a collection of Serratia marcescens isolated from soil revealed that exogenous milk protein increased biofilm productivity up to ten-fold. A select screening of fish pathogens, freshwater and human isolates identified several other species that responded similarly to exogenous protein. The optimal protein concentration was species specific;S. marcescens at 5% milk protein, Aeromonas sp. at 2% - 3%, Flavobacterium columnare at 1% and Pseudomonas aeruginosa at 0.1% - 0.4%. Media supplemented with milk protein also increased the cell counts in biofilm as well as the protein incorporated into the biofilm matrix. These data suggest that relatively high concentrations of exogenous protein may serve as an environmental trigger for biofilm formation, particularly for pathogenic bacteria exposed to relatively high concentrations of protein in bodily fluids and mucosal surfaces.
