A phyllosphere bacterial strain EBL-06 was isolated from wheat leaves. The morphology, cultural characteristics, phospholipid fatty acids, physiological and antagonistic fungus activities of this strain were investiga...A phyllosphere bacterial strain EBL-06 was isolated from wheat leaves. The morphology, cultural characteristics, phospholipid fatty acids, physiological and antagonistic fungus activities of this strain were investigated. A phylogenetic tree was constructed by comparing with the published 16S rDNA sequences of the relevant bacteria. The results showed that the isolate EBL-06 was a strain of Paenibacillus polymyxa; this strain performed a high level of antagonistic fungus activity toward a broad spectrum of phytopathogens, such as Botrytis cinerea, Cladosporium cucumerinum, Fusarium spp. The isolate EBL-06 can grow well using monosodium glutamate wastewater （MGW） and potato wastewater （PW） as culture medium. The maximum yield of 6.5 × 10^9 CFU/mL of the isolate EBL-06 anti-fungus biocontrol agent was reached in 15 hr cultivation at 28℃, pH 6.0-7.5 using the mixture of MGW and PW （1：9）.展开更多
The four effective antagonistic Bacillus strains, isolated from the rhizosphere soil of cucumber in a greenhouse, produced antifungal volatiles. These volatiles strongly inhibited the growth of the most tested pathoge...The four effective antagonistic Bacillus strains, isolated from the rhizosphere soil of cucumber in a greenhouse, produced antifungal volatiles. These volatiles strongly inhibited the growth of the most tested pathogenic fungi with wide host plants, induced the mycelial morphological abnormalities, and decreased the sclerotoid production of Sclerotinia sclerotiorum in sealed plates. Spores of Botrytis cinerea exposed to these volatiles for 24-48 h in cavity slides cracked and the sporaceous inclusion became brown and effused to the suspension. An interesting phenomenon observed was that all the bacterial volatiles exhibited intense inhibitory activities against the pigment formation of tested pathogenic fungi, including Ascochyta citrullina, Alternaria solani, Alternaria brassicae, and so on. Interactions mediated by microbial volatiles could be widespread in soils, and volatiles may play an important role in reducing disease levels. A phylogenetic analysis based on 16S rDNA sequence placed the four bacteria in three species Paenibacillus polymyxa （BMP-11）, Bacillus subtilis （BL02）, and Bacillus pumilus （BSH-4 and ZB 13）. Through headspace sampling and GC-MS analysis, a rich profile was found from B. subtilis and overlapping volatile patterns could be found among the different species. Studies are under the way to find the possible action mechanisms and to seek the effective application of bacterial volatiles in greenhouse.展开更多
With the ever-growing strict prohibitions on antibiotic growth promoters(AGP)in animal production,in-feed probiotics are becoming attractive alternatives to antibiotics in the poultry industry.To investigate the effec...With the ever-growing strict prohibitions on antibiotic growth promoters(AGP)in animal production,in-feed probiotics are becoming attractive alternatives to antibiotics in the poultry industry.To investigate the effects of Paenibacillus polymyxa 10 and Lactobacillus plantarum 16 on the growth performance and intestinal health of broilers,540 male Cobb 500 broilers of 1 d old were randomly divided into 3 groups with 6 replicates per group and 30 chicks per replicate.Broilers were fed with either a basal diet or basal diets supplemented with 1×108 colony-forming units(CFU)/kg P.polymyxa 10(BSC10)or L.plantarum 16(Lac16)for 42 d.Results showed that Lac16 treatment improved(P<0.05)the growth performance(body weight and feed conversion)of broilers at the starter phase,while BSC10 treatment slightly improved(P>0.05)the growth performance of the starter phase broilers.The increased villus height(P<0.05)at d 14,21 and 42 and villus height to crypt depth ratio(P<0.05)at d 14 and 21 were observed in the ileum of the 2 probiotic groups.Besides,transmission electron microscopy results showed that the 2 probiotics enhanced the intestinal epithelial barrier.Both probiotic treatments up-regulated(P<0.05)the mRNA expression of fatty acid binding protein 1(FABP1)and sodium-dependent glucose transporters-1(SGLT-1)in the ileal mucosa of broilers at d 21.In addition,BSC10 and Lac16 treatments significantly(P<0.05)increased the relative abundance of short-chain fatty acids-producing bacteria,such as Butyricicoccus pullicaecorum,Faecalibacterium prausnitzii,Lachnospira and Cop-rococcu,and significantly(P<0.05)decreased the relative abundance of enteric pathogens(Escherichia coli,Bacteroides fragilis and Shigella sonnei).Furthermore,the 2 probiotic treatments also increased the positive connection among the intestinal microbes and the carbohydrate metabolism-related pathways of the intes-tinal bacteria(P<0.05),with decreasing(P<0.05)nucleotides biosynthesis-related pathways of the intestinal bacteria.Overall,these results suggest that展开更多
Bacterial adhesion is crucial to the dissolution of minerals and rocks. By employing dialysis method, we designed comparative experiments to investigate the dissolution behavior of anorthite with the mediation of both...Bacterial adhesion is crucial to the dissolution of minerals and rocks. By employing dialysis method, we designed comparative experiments to investigate the dissolution behavior of anorthite with the mediation of both adhered and non-adhered Paenibacillus polymyxa. The results show that during 10 experimental days, the dissolution of anorthite was promoted considerably by P. polymyxa and metabolites. Nanoscale precipitates were formed in contact experiment. Anorthite has a higher release of Ca and lower releases of Al and Si in dialysis experiment than in contact experiment. The difference implies that the release of Ca is controlled by mechanism of proton-exchange, whereas those of A1 and Si are controlled by ligand-complexation in which A1-O-Si bonds are destroyed first. Kinetically the release of Ca is controlled mainly by surface reaction and leached-layer diffusion. Both of them are restrained by adhered bacteria. The releases of AI and Si are controlled mainly by surface reaction, which is accelerated by adhered bacteria.展开更多
基金supported by the National Natural Science Foundation of China (No. 30600082)the Knowledge Innovation Program of Chinese Academy of Sciences (No.KSCX2-YW-G-054-2)the Key Technologies R&D Program of China (No. 2008BADA7B01)
文摘A phyllosphere bacterial strain EBL-06 was isolated from wheat leaves. The morphology, cultural characteristics, phospholipid fatty acids, physiological and antagonistic fungus activities of this strain were investigated. A phylogenetic tree was constructed by comparing with the published 16S rDNA sequences of the relevant bacteria. The results showed that the isolate EBL-06 was a strain of Paenibacillus polymyxa; this strain performed a high level of antagonistic fungus activity toward a broad spectrum of phytopathogens, such as Botrytis cinerea, Cladosporium cucumerinum, Fusarium spp. The isolate EBL-06 can grow well using monosodium glutamate wastewater （MGW） and potato wastewater （PW） as culture medium. The maximum yield of 6.5 × 10^9 CFU/mL of the isolate EBL-06 anti-fungus biocontrol agent was reached in 15 hr cultivation at 28℃, pH 6.0-7.5 using the mixture of MGW and PW （1：9）.
基金the National Key Technology R&D Program of China (2006BAD08A03)the Shandong Agricultural University Postdoctoral Foundation (200603065)
文摘The four effective antagonistic Bacillus strains, isolated from the rhizosphere soil of cucumber in a greenhouse, produced antifungal volatiles. These volatiles strongly inhibited the growth of the most tested pathogenic fungi with wide host plants, induced the mycelial morphological abnormalities, and decreased the sclerotoid production of Sclerotinia sclerotiorum in sealed plates. Spores of Botrytis cinerea exposed to these volatiles for 24-48 h in cavity slides cracked and the sporaceous inclusion became brown and effused to the suspension. An interesting phenomenon observed was that all the bacterial volatiles exhibited intense inhibitory activities against the pigment formation of tested pathogenic fungi, including Ascochyta citrullina, Alternaria solani, Alternaria brassicae, and so on. Interactions mediated by microbial volatiles could be widespread in soils, and volatiles may play an important role in reducing disease levels. A phylogenetic analysis based on 16S rDNA sequence placed the four bacteria in three species Paenibacillus polymyxa （BMP-11）, Bacillus subtilis （BL02）, and Bacillus pumilus （BSH-4 and ZB 13）. Through headspace sampling and GC-MS analysis, a rich profile was found from B. subtilis and overlapping volatile patterns could be found among the different species. Studies are under the way to find the possible action mechanisms and to seek the effective application of bacterial volatiles in greenhouse.
基金supported by the Natural Science Foundation of Zhejiang Province(No.2014C32059 and No.2006C12086)the National High-Tech R&D Program Project(863)of China(No.2013AA102803D)
文摘With the ever-growing strict prohibitions on antibiotic growth promoters(AGP)in animal production,in-feed probiotics are becoming attractive alternatives to antibiotics in the poultry industry.To investigate the effects of Paenibacillus polymyxa 10 and Lactobacillus plantarum 16 on the growth performance and intestinal health of broilers,540 male Cobb 500 broilers of 1 d old were randomly divided into 3 groups with 6 replicates per group and 30 chicks per replicate.Broilers were fed with either a basal diet or basal diets supplemented with 1×108 colony-forming units(CFU)/kg P.polymyxa 10(BSC10)or L.plantarum 16(Lac16)for 42 d.Results showed that Lac16 treatment improved(P<0.05)the growth performance(body weight and feed conversion)of broilers at the starter phase,while BSC10 treatment slightly improved(P>0.05)the growth performance of the starter phase broilers.The increased villus height(P<0.05)at d 14,21 and 42 and villus height to crypt depth ratio(P<0.05)at d 14 and 21 were observed in the ileum of the 2 probiotic groups.Besides,transmission electron microscopy results showed that the 2 probiotics enhanced the intestinal epithelial barrier.Both probiotic treatments up-regulated(P<0.05)the mRNA expression of fatty acid binding protein 1(FABP1)and sodium-dependent glucose transporters-1(SGLT-1)in the ileal mucosa of broilers at d 21.In addition,BSC10 and Lac16 treatments significantly(P<0.05)increased the relative abundance of short-chain fatty acids-producing bacteria,such as Butyricicoccus pullicaecorum,Faecalibacterium prausnitzii,Lachnospira and Cop-rococcu,and significantly(P<0.05)decreased the relative abundance of enteric pathogens(Escherichia coli,Bacteroides fragilis and Shigella sonnei).Furthermore,the 2 probiotic treatments also increased the positive connection among the intestinal microbes and the carbohydrate metabolism-related pathways of the intes-tinal bacteria(P<0.05),with decreasing(P<0.05)nucleotides biosynthesis-related pathways of the intestinal bacteria.Overall,these results suggest that
基金supported by National Basic Research Program of China (Grant No. 2007CB815603)National Natural Science Foundation of China (Grant No. 40802015)Ph. D. Programs Foundation of Ministry of Education of China (Grant Nos. 20050284043,20050284044)
文摘Bacterial adhesion is crucial to the dissolution of minerals and rocks. By employing dialysis method, we designed comparative experiments to investigate the dissolution behavior of anorthite with the mediation of both adhered and non-adhered Paenibacillus polymyxa. The results show that during 10 experimental days, the dissolution of anorthite was promoted considerably by P. polymyxa and metabolites. Nanoscale precipitates were formed in contact experiment. Anorthite has a higher release of Ca and lower releases of Al and Si in dialysis experiment than in contact experiment. The difference implies that the release of Ca is controlled by mechanism of proton-exchange, whereas those of A1 and Si are controlled by ligand-complexation in which A1-O-Si bonds are destroyed first. Kinetically the release of Ca is controlled mainly by surface reaction and leached-layer diffusion. Both of them are restrained by adhered bacteria. The releases of AI and Si are controlled mainly by surface reaction, which is accelerated by adhered bacteria.
