The UV irradiation is used for removing Antibiotic Resistant Bacteria(ARB)and Antibiotic Resistance Genes(ARG)from wastewater treatment.Bacteriophages are viruses that infect within bacteria,are recognized for bacteri...The UV irradiation is used for removing Antibiotic Resistant Bacteria(ARB)and Antibiotic Resistance Genes(ARG)from wastewater treatment.Bacteriophages are viruses that infect within bacteria,are recognized for bacterial control.The influence of some parameters in quantification and performance influencing of pathogen demobilization could be considered in disinfection of wastewater.The comparison of Polyvalent phage(NE1)versus Coliphage(NE4)in suppressing a bacterium Escherichia coli(NDM-1:b-lactam-resistant)with UV irradiation was observed the efficacy in reduction of cells in the disinfection and parameter process.The results with the effect of UV-C irradiation on NDM-1 infected with 1%of NE4 showed a decrease of cells from 8×10^(6)to 2×10^(5)in 60 min with UV-C dose.The NDM1(E.coli)was infected with 1%of NE4(Polyvalent Phage)under magnetic stirring for 1 h,the cells count was 8×10^(6).After 1 h in UV-C e×posure,the cells number reached 3×10^(5).The NDM1 that was e×posed in 1 h of UV-C irradiation and then was infected with 1%of NE4.Cells counting were done 24 h after this procedure.These cells were e×posed in UV-C and showed a reduction in the number of cells from 1×10^(8)to 4×10^(5)after 60 min.The results indicate that bacteriophages can mitigate bacteria species,and combined the conventional water disinfection technologies that can support the microbial safety control strategies.展开更多
This study aimed to examine the effects of inoculating Fritillaria taipaiensis P.Y.Li leaves with different strains ofpotassium-solubilizing bacteria (KSB), or combinations thereof, focusing on aspects of photosynthes...This study aimed to examine the effects of inoculating Fritillaria taipaiensis P.Y.Li leaves with different strains ofpotassium-solubilizing bacteria (KSB), or combinations thereof, focusing on aspects of photosynthesis and physiologicaland biochemical characteristics. At present, some studies have only studied the rhizosphere microbialcommunity characteristics of F. taipaiensis and have not discussed the effects of different microbial species on thegrowth promotion of F. taipaiensis. This paper will start from the perspective of potassium-solubilizing bacteria toconduct an in-depth study. Seed cultivation commenced at the base with three different KSBs in early October2022. The growth of F. taipaiensis leaves was observed after different treatments. Both single-plant and compoundinoculations were executed. A total of eight treatment groups were established, with aseptic fertilizer and sterilizedsoil functioning as the control group. The results reveal that intercellular CO_(2) concentration (Ci), stomatal conductance(Gs), and transpiration rate (Tr) were at their apex in the S7 group. Most treatment groups exhibited anincrease in leaf area, photosynthetic pigment content, soluble sugar, soluble protein, Superoxide Dismutase(SOD), Peroxidase (POD), Catalase (CAT) activities, and proline content. The expression levels of POD, SOD,and CAT genes were evaluated, following inoculation with different KSB. The highest was the S7 group. Theinoculation with various KSB, or combinations thereof, appears to bolster the growth and development of F. taipaiensis.The composite inoculation group S7, comprising Bacillus cereus, Burkholderia cepacia, and Bacillus subtilis,manifested the most favorable impact on the diverse indices of F. taipaiensis, thereby furnishing valuableinsights for the selection of bacterial fertilizer in the artificial cultivation of F. taipaiensis.展开更多
Trifunctional Cu-mesh/Cu_(2)O@FeO nanoarrays heterostructure is designed and fabricated by integrating CuCu_(2)O@FeO nanoarrays onto Cu-mesh(CM)via an in situ growth and phase transformation process.It is successfully...Trifunctional Cu-mesh/Cu_(2)O@FeO nanoarrays heterostructure is designed and fabricated by integrating CuCu_(2)O@FeO nanoarrays onto Cu-mesh(CM)via an in situ growth and phase transformation process.It is successfully applied to efficiently mitigate the antibiotic pollution,including degradation of antibiotics,inactivation of antibiotic-resistant bacteria(ARB),and damage of antibiotics resistance genes(ARGs).Under visible-light irradiation,CM/CuCu_(2)O@FeO nanoarrays exhibit a superior degradation efficiency on antibiotics(e.g.,up to 99%in 25 min for tetracycline hydrochloride,TC),due to the generated reactive oxygen species(ROS),especially the dominant·O^(2−).It can fully inactivate E.coli(HB101)with initial number of~108 CFU mL^(−1) in 10 min,which is mainly attributed to the synergistic effects of 1D nanostructure,dissolved metal ions,and generated ROS.Meanwhile,it is able to damage ARGs after 180 min of photodegradation,including tetA(vs TC)of 3.3 log 10,aphA(vs kanamycin sulfate,KAN)of 3.4 log 10,and tnpA(vs ampicillin,AMP)of 4.4 log 10,respectively.This work explores a green way for treating antibiotic pollution under visible light.展开更多
Soil contains a great diversity of microorganisms, among which are bacteria. This study aimed to explore bacterial diversity in soil samples in Brazzaville in the Republic of the Congo. Environmental DNA was extracted...Soil contains a great diversity of microorganisms, among which are bacteria. This study aimed to explore bacterial diversity in soil samples in Brazzaville in the Republic of the Congo. Environmental DNA was extracted. The illumina MiSeq sequencing was held and the diversity indices have been computed. Illumina MiSeq sequencing revealed 21 Phyla, four of which were abundant: Proteobacteria, Acidobacteria, Actinobacteria and Bacteroidetes. Soil microbial communities in the studied samples were phylogenetically diverse but with a stable community structure. 17 classes are represented with relative abundances of Rihzobiales, Bacillales, Actinomycetales and Acidobacteriales. 40 families, the Alphaproteobacteria, the Bacilli and the 12 Actinobacteria. 83 orders among which the Rhizobiales are the most abundant followed by Bacillales and the least abundant followed by the Flavobacteriaceae. Of the 28 genera listed, the Bradyrhizobium is the most dominant in Mw3 and Mw4. 25 listed species, Bradyrhizobium, Bacillus, Actinoplanes, and Candidatu coribacter Acidobacterium are the most abundant species. The Shannon indices of Mw3 and Mw4 are equal, the H’max of Mw4 is greater than the H’max of Mw3. The Simpson index of Mw4 is equal to the Simpson index of Mw3, and the Pielou index (J) of Mw4 is less than the R of Mw3, but very close. This study opens interesting perspectives on the knowledge and exploitation of telluric bacteria in several areas of life.展开更多
AIM To investigate the diversity of bacterial lactase genes in the intestinal contents of mice with antibiotics-induced diarrhea.METHODS Following 2 d of adaptive feeding, 12 specific pathogenfree Kunming mice were ra...AIM To investigate the diversity of bacterial lactase genes in the intestinal contents of mice with antibiotics-induced diarrhea.METHODS Following 2 d of adaptive feeding, 12 specific pathogenfree Kunming mice were randomly divided into the control group and model group. The mouse model of antibiotics-induced diarrhea was established by gastric perfusion with mixed antibiotics(23.33 m L·kg^(-1)·d^(-1)) composed of gentamicin sulfate and cephradine capsules administered for 5 days, and the control group was treated with an equal amount of sterile water. Contents of the jejunum and ileum were then collected and metagenomic DNA was extracted, after which analysis of bacterial lactase genes using operational taxonomic units(OTUs) was carried outafter amplification and sequencing.RESULTS OTUs were 871 and 963 in the model group and control group, respectively, and 690 of these were identical. There were significant differences in Chao1 and ACE indices between the two groups(P < 0.05). Principal component analysis, principal coordination analysis and nonmetric multidimensional scaling analyses showed that OTUs distribution in the control group was relatively intensive, and differences among individuals were small, while in the model group, they were widely dispersed and more diversified. Bacterial lactase genes from the intestinal contents of the control group were related to Proteobacteria, Actinobacteria, Firmicutes and unclassified bacteria. Of these, Proteobacteria was the most abundant phylum. In contrast, the bacterial population was less diverse and abundant in the model group, as the abundance of Bradyrhizobium sp. BTAi1, Agrobacterium sp. H13-3, Acidovorax sp. KKS102, Azoarcus sp. KH32 C and Aeromonas caviae was lower than that in the control group. In addition, of the known species, the control group and model group had their own unique genera, respectively.CONCLUSION Antibiotics reduce the diversity of bacterial lactase genes in the intestinal contents, decrease the abundance of lactase gene, change the lactase gene strains, and transform their structures.展开更多
PCR and DNA sequencing were used to screen and characterize integrons and resistance genes in Gram-negative bacteria isolated from seafood products in Japan.A total of 215 Gram-negative bacteria were isolated from loc...PCR and DNA sequencing were used to screen and characterize integrons and resistance genes in Gram-negative bacteria isolated from seafood products in Japan.A total of 215 Gram-negative bacteria were isolated from local and imported seafood samples collected from retail markets in Hiroshima Prefecture.Class 1 integrons containing gene cassettes encoding resistance to trimethoprim展开更多
The class 1 integron and complex gene cassettes among different species of clinical isolates in northern China were characterized in this study. 383 clinical isolates were obtained from northern China, and class 1 int...The class 1 integron and complex gene cassettes among different species of clinical isolates in northern China were characterized in this study. 383 clinical isolates were obtained from northern China, and class 1 integrons containing gene cassettes widely distributed among gram negative clinical isolates was observed. We find that the class 1 integron showed positive correlation with multidrug resistance phenotype of gram negative bacteria. In addition, we find that isolates belonged to one species harbored different types of gene cassette arrays, while same types of gene cassette arrays were observed in different species of isolates. The diversity of gene cassette arrays among the isolates indicated the complexity of multidrug resistance in clinical isolates in northern China.展开更多
Background: Residual feed intake(RFI) describes an animal’s feed efficiency independent of growth performance.The objective of this study was to determine differences in growth performance, carcass traits, major bact...Background: Residual feed intake(RFI) describes an animal’s feed efficiency independent of growth performance.The objective of this study was to determine differences in growth performance, carcass traits, major bacteria attached to ruminal solids-fraction, and ruminal epithelium gene expression between the most-efficient and the least-efficient beef cattle. One-hundred and forty-nine Red Angus cattle were allocated to three contemporary groups according to sex and herd origin. Animals were fed a finishing diet in confinement for 70 d to determine the RFI category for each. Within each group, the two most-efficient(n = 6; RFI coefficient =-2.69 ± 0.58 kg dry matter intake(DMI)/d) and the two least-efficient animals(n = 6; RFI coefficient = 3.08 ± 0.55 kg DMI/d) were selected. Immediately after slaughter, ruminal solids-fraction and ruminal epithelium were collected for bacteria relative abundance and epithelial gene expression analyses, respectively, using real-time PCR.Results: The most-efficient animals consumed less feed(P = 0.01; 5.03 kg less DMI/d) compared with the leastefficient animals. No differences(P > 0.10) in initial body weight(BW), final BW, and average daily gain(ADG) were observed between the two RFI classes. There were no significant RFI × sex effects(P > 0.10) on growth performance.Compared with the least-efficient group, hot carcass weight(HCW), ribeye area(REA), and kidney, pelvic, and heart fat(KPH) were greater(P ≤ 0.05) in the most-efficient cattle. No RFI × sex effect(P > 0.10) for carcass traits was detected between RFI groups. Of the 10 bacterial species evaluated, the most-efficient compared with least efficient cattle had greater(P ≤ 0.05) relative abundance of Eubacterium ruminantium, Fibrobacter succinogenes, and Megasphaera elsdenii, and lower(P ≤ 0.05) Succinimonas amylolytica and total bacterial density. No RFI × sex effect on ruminal bacteria was detected between RFI groups. Of the 34 genes evaluated in ruminal epithelium, the mostefficient cattle had greater(P ≤ 0.05) abundance of genes involved in VFA absorption, metabolism, ketogenesis, and immune/inflammation-response. The RFI × sex interactions indicated that responses in gene expression between RFI groups were due to differences in sex. Steers in the most-efficient compared with least-efficient group had greater(P ≤ 0.05) expression of SLC9 A1, HIF1 A, and ACO2. The most-efficient compared with least-efficient heifers had greater(P ≤ 0.05) m RNA expression of BDH1 and lower expression(P ≤ 0.05) of SLC9 A2 and PDHA1.Conclusions: The present study revealed that greater feed efficiency in beef cattle is associated with differences in bacterial species and transcriptional adaptations in the ruminal epithelium that might enhance nutrient delivery and utilization by tissues. The lack of RFI × sex interaction for growth performance and carcass traits indicates that sex may not play a major role in improving these phenotypes in superior RFI beef cattle. However, it is important to note that this result should not be considered a solid biomarker of efficient beef cattle prior to further examination due to the limited number of heifers compared with steers used in the study.展开更多
Dimethylsulfoniopropionate(DMSP) is mainly produced by marine phytoplankton as an osmolyte, antioxidant,predator deterrent, or cryoprotectant. DMSP is also an important carbon and sulfur source for marine bacteria.Bac...Dimethylsulfoniopropionate(DMSP) is mainly produced by marine phytoplankton as an osmolyte, antioxidant,predator deterrent, or cryoprotectant. DMSP is also an important carbon and sulfur source for marine bacteria.Bacteria may metabolize DMSP via the demethylation pathway involving the DMSP demethylase gene(dmdA) or the cleavage pathway involving several different DMSP lyase genes. Most DMSP released into seawater is degraded by bacteria via demethylation. To test a hypothesis that the high gene frequency of dmdA among major marine taxa results in part from horizontal gene transfer(HGT) events, a total of thirty-one bacterial strains were isolated from Arctic Kongsfjorden seawater in this study. Analysis of 16S rRNA gene sequences showed that,except for strains BSw22118, BSw22131 and BSw22132 belonging to the genera Colwellia, Pseudomonas and Glaciecola, respectively, all bacteria fell into the genus Pseudoalteromonas. DmdA genes were detected in five distantly related bacterial strains, including four Arctic strains(Pseudoalteromonas sp. BSw22112, Colwellia sp.BSw22118, Pseudomonas sp. BSw22131 and Glaciecola sp. BSw22132) and one Antarctic strain(Roseicitreum antarcticum ZS2–28). Their dmdA genes showed significant similarities(97.7%–98.3%) to that of Ruegeria pomeroyi DSS–3, which was originally isolated from temperate coastal seawater. In addition, the sequence of the gene transfer agent(GTA) capsid protein gene(g5) detected in Antarctic strain ZS2–28 exhibited a genetically closely related to that of Ruegeria pomeroyi DSS–3. Among the five tested strains, only Pseudomonas sp. BSw22131 could grow using DMSP as the sole carbon source. The results of this study support the hypothesis of HGT for dmdA among taxonomically heterogeneous bacterioplankton, and suggest a wide distribution of functional gene(i.e., dmdA) in global marine environments.展开更多
To establish a rapid identification method for common pathogenic bacteria on the basis of molecular biology and to construct a preliminary Polymerase Chain Reaction-Capillary Electrophoresis - Restriction Fragment Len...To establish a rapid identification method for common pathogenic bacteria on the basis of molecular biology and to construct a preliminary Polymerase Chain Reaction-Capillary Electrophoresis - Restriction Fragment Length Polymorphism (PCR-CE-RFLP) database of bacteria isolated from clinical specimens frequently, 183 strains collected from clinical samples belonging to 12 genera and 19 species whose biochemical characterizations corresponded to the typical ones were examined. The genomic DNAs were amplified by two pairs of fluorescence labeled primers aiming at 16S rRNA gene and 16S-23S rRNA spacer region gene respectively at the same time. PCR products were then digested by restriction endonuclease HaeⅢ incompletely before taking capillary electrophoresis. The results with the PCR-CE-RFLP patterns of 16S rRNA genes were just alike within some genera, but when it comes to 16S-23S rRNA spacer region genes, each bacterium showed a unique pattern, which can be distinguished from each other easily. It seems that PCR-CE-RFLP patterns of 16S rRNA gene could only be used to classify the bacteria into family level, whereas the data of 16S-23S rRNA spacer region gene could be utilized to identify the whole microorganisms as precisely as the species level. In spite of the data of the spacer region gene alone can be sufficiently to verify the whole bacteria, we insist that the 16S rRNA gene could be of some assistant in case that there should be lots of families of bacteria, in which some similar ones, with the same RFLP data of 16S-23S rRNA spacer region gene, may coexist. This study proves that the utility of PCR-CE-RFLP is a convenient, rapid method to identify pathogenic bacteria, and is also a quick diagnosis measure for application to clinical use.展开更多
According to the sequence of the bile salt hydrolase （BSH） gene of Bifidobacterium and the restriction enzyme cutting sites of expression vector pNZ8148, primers were designed and the bile salt hydrolase （BSH） gen...According to the sequence of the bile salt hydrolase （BSH） gene of Bifidobacterium and the restriction enzyme cutting sites of expression vector pNZ8148, primers were designed and the bile salt hydrolase （BSH） gene was gotten from Bacillus bifidus ATCC 29521 by PCR. BSH gene was inserted into lactic acid bacteria expression vector pNZ8148 to construct the recombinant pNZ8148-BSH. The recombinant pNZ8148-BSH was transferred into lactic acid bacteria NZ9000 with electrotransformation method. And the recombinant which could express BSH protein was obtained. It was identified by SDS-PAGE electrophoresis and activity verification. The result could provide a rationale reference for expressing BSH in lactic acid bacteria.展开更多
Cultured Apostichopus japonicus in China suffers from a kind of skin ulceration disease that has caused severe economic loss in recent years. The disease,pathogens of which are supposed to be bacteria by most research...Cultured Apostichopus japonicus in China suffers from a kind of skin ulceration disease that has caused severe economic loss in recent years. The disease,pathogens of which are supposed to be bacteria by most researchers,is highly infectious and can often cause all individuals in the same culture pool to die in a very short time. The 16S rRNA gene phylogenesis of the culturable bacteria from the lesions of diseased individuals was conducted to study the biodiversity of the bacterial communities in the lesions and to identify probable pathogen(s) associated with this kind of disease. S. japonica samples were selected from a hatchery located in the eastern part of Qingdao,China. Bacterial universal primers GM5F and DS907R were used to amplify the 16S rRNA gene of bacteria colonies,and touchdown PCR was performed to amplify the target sequences. The results suggest that γ-proteobacteria(Alteromonadales and Vibrionales) of CFB group,many strains of which have been also determined as pathogens in other marine species,are the predominant bacterial genera of the diseased Apostichopus japonicus individuals.展开更多
Planktonic bacteria are abundant in the Chukchi Borderland region. However, little is known about their di- versity and the roles of various bacteria in the ocean. Seawater samples were collected from two stations K2S...Planktonic bacteria are abundant in the Chukchi Borderland region. However, little is known about their di- versity and the roles of various bacteria in the ocean. Seawater samples were collected from two stations K2S and K4S where sea ice was melting obviously. The analysis of water samples with fluorescence in situ hybridization （FISH） showed that DMSP-degrading bacteria accounted for 13% of the total bacteria at the station K2S. No aerobic anoxygenic phototrophic （AAP） bacteria were detected in both samples. The bacterial communities were characterized by two 16S rRNA gene clone libraries. Sequences fell into four major lineages of the domain Bacteria, including Proteobacteria （Alpha, Beta and Gamma subclasses）, Bac- teroidetes, Actinobacteria and Firmicutes. No significant difference was found between the two clone li- braries. SAR11 and Rhodobacteraceae clades of Alphaproteobacteria and Pseudoalteromonas of Gammapro- teobacteria constituted three dominant fractions in the clone libraries. A total of 191 heterotrophic bacterial strains were isolated and 76% showed extracellular proteolytic activity. Phylogenetic analysis reveals that the isolates fell into Gammaproteobacteria, Bacteroidetes, Actinobacteria and Firmicutes. The most common genus in both the bacterial isolates and protease-producing bacteria was Pseudoalteromonas. UniFrac data showed suggestive differences in bacterial communities between the Chukchi Borderland and the northern Bering Sea.展开更多
Phenazines are secondary metabolites with broad spectrum antibiotic activity and thus show high potential in biological control of pathogens. In this study, we identified phenazine biosynthesis （phz） genes in two ge...Phenazines are secondary metabolites with broad spectrum antibiotic activity and thus show high potential in biological control of pathogens. In this study, we identified phenazine biosynthesis （phz） genes in two genome-completed plant pathogenic bacteria Pseudomonas syringae pv. tomato （Pst） DC3000 and Xanthomonas oryzae pv. oryzae （Xoo） PXO99A. Unlike the phz genes in typical phenazine-producing pseudomonads, phz homologs in Pst DC3000 and Xoo PXO99A consisted of phzC/D/E/F/G and phzC/E1/E2/F/G, respectively, and the both were not organized into an operon. Detection experiments demonstrated that phenazine-l-carboxylic acid （PCA） of Pst DC3000 accumulated to 13.4 IJg L-1, while that of Xoo PXO99A was almost undetectable. Moreover, Pst DC3000 was resistant to 1 mg mL-1 PCA, while Xoo PXO99A was sensitive to 50 IJg mL ~ PCA. Furthermore, mutation of phzF blocked the PCA production and significantly reduced the pathogenicity of Pst DC3000 in tomato, while the complementary strains restored these phenotypes. These results revealed that Pst DC3000 produces low level of and is resistant to phenazines and thus is unable to be biologically controlled by phenazines. Additionally, phz-mediated PCA production is required for full pathogenicity of Pst DC3000. To our knowledge, this is the first report of PCA production and its function in pathogenicity of a plant pathogenic P. syringae strain.展开更多
[Objective] Marine sediment from Tianjin Port has a extremely high salinity.The bacteria which live in such habitats have evolved distinct physiological,metabolic,and morphological characteristics to survive.The objec...[Objective] Marine sediment from Tianjin Port has a extremely high salinity.The bacteria which live in such habitats have evolved distinct physiological,metabolic,and morphological characteristics to survive.The objective of this study is to identify all the specific salt-tolerant characteristics and the genetic evolution of the bacteria in the sediment.[Methods] In this study,the total DNA of sediment from Tianjin Port was extracted,and 16S rDNA was used to conduct an analysis of the fauna of sediment bacteria. We also isolated sediment bacteria using beef extract-peptone media with seven different NaCl concentrations (0,0.5%,2%,5%,10%,15%,and 20%),aiming to analyze the dominant species of halophilous bacteria under different salinities.[Results] 1) With each stepwise increase of salinity from 0.5% to 20%,the total number of isolated bacterial colonies decreased.14 strains of bacteria were identified and classified by the16S rDNA sequencing analysis.Of these,four could tolerate 0~2% salinity,four could tolerate 0~5% salinity,one could tolerate 0~15% salinity,and one tolerated within the full 0~20% salinity range.Further four strains were only able to tolerate within a few narrow salinity ranges.such as 5%~10%,10%~15%,10%~20% and 15%~20%;2) The quantity of bacteria strains that can be isolated from the marine sediment decreased with the increase of salinity. Also, the Shannon wiener index and species richness index of marine sediment bacteria decreased significantly from 5% salinity.However,there were no significant differences in the species evenness index;3) When the salinity was 0~10%,the dominant species was Bacillus.When the salinity was 15%, Halomonas was the dominant species.When the salinity was 20%,there were no significant differences in the proportions of these species.[Conclusion] Our results showed that some bacteria could tolerate living conditions with high salinity,and we even found a species which can tolerate a wide range of salinities (0~20%).In further study,it would be valuable to analyze these bacteria's unique physiological and biochemical functions that allow them to adapt to environments with high salinity.It can provide theories to promote the development of microbial population resources in marine sediment and the reclaimation of salinized soil by salt tolerant microorganisms.展开更多
This study investigated differences in the community structure and environmental responses of the bacterial community in sediments of the Bohai Sea.Illumina high-throughput sequencing technology and real-time PCR were...This study investigated differences in the community structure and environmental responses of the bacterial community in sediments of the Bohai Sea.Illumina high-throughput sequencing technology and real-time PCR were used to assay the bacterial 16S rRNA genes in the surface sediments of 13 sampling stations in the Bohai Sea.The results showed that sediments at the majority of the 13 sampling stations were contaminated by heavy metal mercury.The main phyla of bacteria recorded included Proteobacteria(52.92%),Bacteroidetes(11.76%),Planctomycetes(7.39%),Acidobacteria(6.53%)and Chloroflexi(4.97%).The genus with the highest relative abundance was Desulfobulbus(4.99%),which was the dominant genus at most sampling stations,followed by Lutimonas and Halioglobus.The main factors influencing bacterial community structure were total organic carbon,followed by depth and total phosphorus.The content of lead,cadmium,chromium,copper and zinc had a consistent effect on community structure.Arsenic showed a negative correlation with bacterial community structure in most samples,while the impact of mercury on community structure was not significant.The bacterial community in sediment samples from the Bohai Sea was rich in diversity and displayed an increase in diversity from high to low latitudes.The data indicated that the Bohai Sea had abundant microbial resources and was rich in bacteria with the potential to metabolize many types of pollutants.展开更多
Improved rice lines were developed frome three parents with the resistance or tolerance to bacterial leaf blight,blast and drought stress,respectively,using single-,double-and three-way crosses.The improved lines were...Improved rice lines were developed frome three parents with the resistance or tolerance to bacterial leaf blight,blast and drought stress,respectively,using single-,double-and three-way crosses.The improved lines were assessed for agro-morphological and yield traits under non-drought stress(NS)and reproductive-stage drought stress(RS)treatments.The mean comparison of traits measured between parent plants and progenies(improved lines)were similar,and there were significant and non-significant differences among the parents and improved lines(genotypes)under NS and RS.Smilarly,there was significant and non-significant differences in the interaction among both parent varieties and improved lines for NS and RS.Cluster and 3D-model of principal component analysis did not generate categorical clusters according to crossing methods,and there were no exclusive crossing method inclined variations under the treatments.The improved lines were high-yielding,disease resistant,and drought-tolerant compared with their parents.All the crossing methods were good for this crop improvement program without preference to any,despite the number of genes introgressed.展开更多
Essential genes are indispensable for the survival of an organism in optimal conditions.Rapid and accurate identifications of new essential genes are of great theoretical and practical significance.Exploring features ...Essential genes are indispensable for the survival of an organism in optimal conditions.Rapid and accurate identifications of new essential genes are of great theoretical and practical significance.Exploring features with predictive power is fundamental for this.Here,we calculate six fractal features from primary gene and protein sequences and then explore their relationship with gene essentiality by statistical analysis and machine learning-based methods.The models are applied to all the currently available identified genes in 27 bacteria from the database of essential genes（DEG）.It is found that the fractal features of essential genes generally differ from those of non-essential genes.The fractal features are used to ascertain the parameters of two machine learning classifiers：Na¨？ve Bayes and Random Forest.The area under the curve（AUC） of both classifiers show that each fractal feature is satisfactorily discriminative between essential genes and non-essential genes individually.And,although significant correlations exist among fractal features,gene essentiality can also be reliably predicted by various combinations of them.Thus,the fractal features analyzed in our study can be used not only to construct a good essentiality classifier alone,but also to be significant contributors for computational tools identifying essential genes.展开更多
This study was conducted to evaluate the influence of wastewater treatment processes on the prevalence of antibiotic resistance fecal coliform (FC) and antibiotic resistance genes (ARGs) of FC. In addition, the occurr...This study was conducted to evaluate the influence of wastewater treatment processes on the prevalence of antibiotic resistance fecal coliform (FC) and antibiotic resistance genes (ARGs) of FC. In addition, the occurrence of antibiotic resistant bacteria (ARB) and antibiotic resistant genes (ARGs) in surface waters receiving wastewater was evaluated. Greater resistance against penicillin (P), colisitin (CT) and ampicillin (AMP) were observed for FC isolated from effluent disinfected by chlorine (71%), than that disinfected by UV (45%). The greatest resistance against six antibiotics was recorded for FC isolates from effluent disinfected by chlorine. The prevalence of tetB and blaSHV was lowest in isolates from chlorine-disinfected effluents. The occurrence of ARG blaSHV was highest in FC isolated from effluent disinfected by UV. A significant correlation was recorded between FC levels in surface waters and the level of bacterial resistance to ampicillin (P SHV in effluents and in surface waters. TetA and tetC were highly prevalent in surface water compared to tetB. The results of the study demonstrate the widespread prevalence of ARB and ARG in wastewater and receiving water bodies. The result indicates that the source of ARB and ARG in surface waters originate from wastewater. Released ARB and ARG may serve as the source of ARG to pathogenic bacteria in surface waters. Disinfection processes may influence the selection of antibiotic resistant patterns of bacteria.展开更多
基金Fundação de Amparo a Pesquisa do Estado de São Paulo(FAPESP)and the Conselho Nacional de Desenvolvimento Científico e Tecnológico(CNPq),São Paulo,Brazil for PhD scholarship(Process N°.141086/2015-7)financial support(Process No.870243/1997-7).
文摘The UV irradiation is used for removing Antibiotic Resistant Bacteria(ARB)and Antibiotic Resistance Genes(ARG)from wastewater treatment.Bacteriophages are viruses that infect within bacteria,are recognized for bacterial control.The influence of some parameters in quantification and performance influencing of pathogen demobilization could be considered in disinfection of wastewater.The comparison of Polyvalent phage(NE1)versus Coliphage(NE4)in suppressing a bacterium Escherichia coli(NDM-1:b-lactam-resistant)with UV irradiation was observed the efficacy in reduction of cells in the disinfection and parameter process.The results with the effect of UV-C irradiation on NDM-1 infected with 1%of NE4 showed a decrease of cells from 8×10^(6)to 2×10^(5)in 60 min with UV-C dose.The NDM1(E.coli)was infected with 1%of NE4(Polyvalent Phage)under magnetic stirring for 1 h,the cells count was 8×10^(6).After 1 h in UV-C e×posure,the cells number reached 3×10^(5).The NDM1 that was e×posed in 1 h of UV-C irradiation and then was infected with 1%of NE4.Cells counting were done 24 h after this procedure.These cells were e×posed in UV-C and showed a reduction in the number of cells from 1×10^(8)to 4×10^(5)after 60 min.The results indicate that bacteriophages can mitigate bacteria species,and combined the conventional water disinfection technologies that can support the microbial safety control strategies.
基金a Key Project of the Natural Science Foundation of Chongqing Education Committee(KJZD-K202101201).
文摘This study aimed to examine the effects of inoculating Fritillaria taipaiensis P.Y.Li leaves with different strains ofpotassium-solubilizing bacteria (KSB), or combinations thereof, focusing on aspects of photosynthesis and physiologicaland biochemical characteristics. At present, some studies have only studied the rhizosphere microbialcommunity characteristics of F. taipaiensis and have not discussed the effects of different microbial species on thegrowth promotion of F. taipaiensis. This paper will start from the perspective of potassium-solubilizing bacteria toconduct an in-depth study. Seed cultivation commenced at the base with three different KSBs in early October2022. The growth of F. taipaiensis leaves was observed after different treatments. Both single-plant and compoundinoculations were executed. A total of eight treatment groups were established, with aseptic fertilizer and sterilizedsoil functioning as the control group. The results reveal that intercellular CO_(2) concentration (Ci), stomatal conductance(Gs), and transpiration rate (Tr) were at their apex in the S7 group. Most treatment groups exhibited anincrease in leaf area, photosynthetic pigment content, soluble sugar, soluble protein, Superoxide Dismutase(SOD), Peroxidase (POD), Catalase (CAT) activities, and proline content. The expression levels of POD, SOD,and CAT genes were evaluated, following inoculation with different KSB. The highest was the S7 group. Theinoculation with various KSB, or combinations thereof, appears to bolster the growth and development of F. taipaiensis.The composite inoculation group S7, comprising Bacillus cereus, Burkholderia cepacia, and Bacillus subtilis,manifested the most favorable impact on the diverse indices of F. taipaiensis, thereby furnishing valuableinsights for the selection of bacterial fertilizer in the artificial cultivation of F. taipaiensis.
基金This work was financially sup-ported by the National Natural Science Foundation of China(NSFC Nos:22171212,21771140,51771138,51979194)International Corporation Project of Shanghai Committee of Science and Technology by China(No.21160710300)International Exchange Grant(IEC/NSFC/201078)through Royal Society UK and NSFC.
文摘Trifunctional Cu-mesh/Cu_(2)O@FeO nanoarrays heterostructure is designed and fabricated by integrating CuCu_(2)O@FeO nanoarrays onto Cu-mesh(CM)via an in situ growth and phase transformation process.It is successfully applied to efficiently mitigate the antibiotic pollution,including degradation of antibiotics,inactivation of antibiotic-resistant bacteria(ARB),and damage of antibiotics resistance genes(ARGs).Under visible-light irradiation,CM/CuCu_(2)O@FeO nanoarrays exhibit a superior degradation efficiency on antibiotics(e.g.,up to 99%in 25 min for tetracycline hydrochloride,TC),due to the generated reactive oxygen species(ROS),especially the dominant·O^(2−).It can fully inactivate E.coli(HB101)with initial number of~108 CFU mL^(−1) in 10 min,which is mainly attributed to the synergistic effects of 1D nanostructure,dissolved metal ions,and generated ROS.Meanwhile,it is able to damage ARGs after 180 min of photodegradation,including tetA(vs TC)of 3.3 log 10,aphA(vs kanamycin sulfate,KAN)of 3.4 log 10,and tnpA(vs ampicillin,AMP)of 4.4 log 10,respectively.This work explores a green way for treating antibiotic pollution under visible light.
文摘Soil contains a great diversity of microorganisms, among which are bacteria. This study aimed to explore bacterial diversity in soil samples in Brazzaville in the Republic of the Congo. Environmental DNA was extracted. The illumina MiSeq sequencing was held and the diversity indices have been computed. Illumina MiSeq sequencing revealed 21 Phyla, four of which were abundant: Proteobacteria, Acidobacteria, Actinobacteria and Bacteroidetes. Soil microbial communities in the studied samples were phylogenetically diverse but with a stable community structure. 17 classes are represented with relative abundances of Rihzobiales, Bacillales, Actinomycetales and Acidobacteriales. 40 families, the Alphaproteobacteria, the Bacilli and the 12 Actinobacteria. 83 orders among which the Rhizobiales are the most abundant followed by Bacillales and the least abundant followed by the Flavobacteriaceae. Of the 28 genera listed, the Bradyrhizobium is the most dominant in Mw3 and Mw4. 25 listed species, Bradyrhizobium, Bacillus, Actinoplanes, and Candidatu coribacter Acidobacterium are the most abundant species. The Shannon indices of Mw3 and Mw4 are equal, the H’max of Mw4 is greater than the H’max of Mw3. The Simpson index of Mw4 is equal to the Simpson index of Mw3, and the Pielou index (J) of Mw4 is less than the R of Mw3, but very close. This study opens interesting perspectives on the knowledge and exploitation of telluric bacteria in several areas of life.
基金Supported by the National Natural Science Foundation of China,No.81573951
文摘AIM To investigate the diversity of bacterial lactase genes in the intestinal contents of mice with antibiotics-induced diarrhea.METHODS Following 2 d of adaptive feeding, 12 specific pathogenfree Kunming mice were randomly divided into the control group and model group. The mouse model of antibiotics-induced diarrhea was established by gastric perfusion with mixed antibiotics(23.33 m L·kg^(-1)·d^(-1)) composed of gentamicin sulfate and cephradine capsules administered for 5 days, and the control group was treated with an equal amount of sterile water. Contents of the jejunum and ileum were then collected and metagenomic DNA was extracted, after which analysis of bacterial lactase genes using operational taxonomic units(OTUs) was carried outafter amplification and sequencing.RESULTS OTUs were 871 and 963 in the model group and control group, respectively, and 690 of these were identical. There were significant differences in Chao1 and ACE indices between the two groups(P < 0.05). Principal component analysis, principal coordination analysis and nonmetric multidimensional scaling analyses showed that OTUs distribution in the control group was relatively intensive, and differences among individuals were small, while in the model group, they were widely dispersed and more diversified. Bacterial lactase genes from the intestinal contents of the control group were related to Proteobacteria, Actinobacteria, Firmicutes and unclassified bacteria. Of these, Proteobacteria was the most abundant phylum. In contrast, the bacterial population was less diverse and abundant in the model group, as the abundance of Bradyrhizobium sp. BTAi1, Agrobacterium sp. H13-3, Acidovorax sp. KKS102, Azoarcus sp. KH32 C and Aeromonas caviae was lower than that in the control group. In addition, of the known species, the control group and model group had their own unique genera, respectively.CONCLUSION Antibiotics reduce the diversity of bacterial lactase genes in the intestinal contents, decrease the abundance of lactase gene, change the lactase gene strains, and transform their structures.
基金supported by a Grant-in-Aid for Scientific Research(No.25460532 and 26.04912)to Tadashi S.from the Ministry of Education,Culture,Sports,Science,and Technology of Japan
文摘PCR and DNA sequencing were used to screen and characterize integrons and resistance genes in Gram-negative bacteria isolated from seafood products in Japan.A total of 215 Gram-negative bacteria were isolated from local and imported seafood samples collected from retail markets in Hiroshima Prefecture.Class 1 integrons containing gene cassettes encoding resistance to trimethoprim
基金supported by Twelfth Five-Year Mega Project of Research on The Prevention and Control of HIV/AIDS,Viral Hepatitis Infectious Diseases 2013ZX10004-217 from the Ministry of Science and Technology,People’s Republic of China,the Project Sponsored by the Young Scholar Scientific Research Foundation of China CDC(No.2013A101)General Program of State Key Laboratory for Infections Disease Prevention and Control(No.2012SKLID205)
文摘The class 1 integron and complex gene cassettes among different species of clinical isolates in northern China were characterized in this study. 383 clinical isolates were obtained from northern China, and class 1 integrons containing gene cassettes widely distributed among gram negative clinical isolates was observed. We find that the class 1 integron showed positive correlation with multidrug resistance phenotype of gram negative bacteria. In addition, we find that isolates belonged to one species harbored different types of gene cassette arrays, while same types of gene cassette arrays were observed in different species of isolates. The diversity of gene cassette arrays among the isolates indicated the complexity of multidrug resistance in clinical isolates in northern China.
文摘Background: Residual feed intake(RFI) describes an animal’s feed efficiency independent of growth performance.The objective of this study was to determine differences in growth performance, carcass traits, major bacteria attached to ruminal solids-fraction, and ruminal epithelium gene expression between the most-efficient and the least-efficient beef cattle. One-hundred and forty-nine Red Angus cattle were allocated to three contemporary groups according to sex and herd origin. Animals were fed a finishing diet in confinement for 70 d to determine the RFI category for each. Within each group, the two most-efficient(n = 6; RFI coefficient =-2.69 ± 0.58 kg dry matter intake(DMI)/d) and the two least-efficient animals(n = 6; RFI coefficient = 3.08 ± 0.55 kg DMI/d) were selected. Immediately after slaughter, ruminal solids-fraction and ruminal epithelium were collected for bacteria relative abundance and epithelial gene expression analyses, respectively, using real-time PCR.Results: The most-efficient animals consumed less feed(P = 0.01; 5.03 kg less DMI/d) compared with the leastefficient animals. No differences(P > 0.10) in initial body weight(BW), final BW, and average daily gain(ADG) were observed between the two RFI classes. There were no significant RFI × sex effects(P > 0.10) on growth performance.Compared with the least-efficient group, hot carcass weight(HCW), ribeye area(REA), and kidney, pelvic, and heart fat(KPH) were greater(P ≤ 0.05) in the most-efficient cattle. No RFI × sex effect(P > 0.10) for carcass traits was detected between RFI groups. Of the 10 bacterial species evaluated, the most-efficient compared with least efficient cattle had greater(P ≤ 0.05) relative abundance of Eubacterium ruminantium, Fibrobacter succinogenes, and Megasphaera elsdenii, and lower(P ≤ 0.05) Succinimonas amylolytica and total bacterial density. No RFI × sex effect on ruminal bacteria was detected between RFI groups. Of the 34 genes evaluated in ruminal epithelium, the mostefficient cattle had greater(P ≤ 0.05) abundance of genes involved in VFA absorption, metabolism, ketogenesis, and immune/inflammation-response. The RFI × sex interactions indicated that responses in gene expression between RFI groups were due to differences in sex. Steers in the most-efficient compared with least-efficient group had greater(P ≤ 0.05) expression of SLC9 A1, HIF1 A, and ACO2. The most-efficient compared with least-efficient heifers had greater(P ≤ 0.05) m RNA expression of BDH1 and lower expression(P ≤ 0.05) of SLC9 A2 and PDHA1.Conclusions: The present study revealed that greater feed efficiency in beef cattle is associated with differences in bacterial species and transcriptional adaptations in the ruminal epithelium that might enhance nutrient delivery and utilization by tissues. The lack of RFI × sex interaction for growth performance and carcass traits indicates that sex may not play a major role in improving these phenotypes in superior RFI beef cattle. However, it is important to note that this result should not be considered a solid biomarker of efficient beef cattle prior to further examination due to the limited number of heifers compared with steers used in the study.
基金The National Natural Science Foundation of China under contract No.41476171the Chinese Polar Environment Comprehensive Investigation and Assessment Program under contract No.CHINARE04-01
文摘Dimethylsulfoniopropionate(DMSP) is mainly produced by marine phytoplankton as an osmolyte, antioxidant,predator deterrent, or cryoprotectant. DMSP is also an important carbon and sulfur source for marine bacteria.Bacteria may metabolize DMSP via the demethylation pathway involving the DMSP demethylase gene(dmdA) or the cleavage pathway involving several different DMSP lyase genes. Most DMSP released into seawater is degraded by bacteria via demethylation. To test a hypothesis that the high gene frequency of dmdA among major marine taxa results in part from horizontal gene transfer(HGT) events, a total of thirty-one bacterial strains were isolated from Arctic Kongsfjorden seawater in this study. Analysis of 16S rRNA gene sequences showed that,except for strains BSw22118, BSw22131 and BSw22132 belonging to the genera Colwellia, Pseudomonas and Glaciecola, respectively, all bacteria fell into the genus Pseudoalteromonas. DmdA genes were detected in five distantly related bacterial strains, including four Arctic strains(Pseudoalteromonas sp. BSw22112, Colwellia sp.BSw22118, Pseudomonas sp. BSw22131 and Glaciecola sp. BSw22132) and one Antarctic strain(Roseicitreum antarcticum ZS2–28). Their dmdA genes showed significant similarities(97.7%–98.3%) to that of Ruegeria pomeroyi DSS–3, which was originally isolated from temperate coastal seawater. In addition, the sequence of the gene transfer agent(GTA) capsid protein gene(g5) detected in Antarctic strain ZS2–28 exhibited a genetically closely related to that of Ruegeria pomeroyi DSS–3. Among the five tested strains, only Pseudomonas sp. BSw22131 could grow using DMSP as the sole carbon source. The results of this study support the hypothesis of HGT for dmdA among taxonomically heterogeneous bacterioplankton, and suggest a wide distribution of functional gene(i.e., dmdA) in global marine environments.
文摘To establish a rapid identification method for common pathogenic bacteria on the basis of molecular biology and to construct a preliminary Polymerase Chain Reaction-Capillary Electrophoresis - Restriction Fragment Length Polymorphism (PCR-CE-RFLP) database of bacteria isolated from clinical specimens frequently, 183 strains collected from clinical samples belonging to 12 genera and 19 species whose biochemical characterizations corresponded to the typical ones were examined. The genomic DNAs were amplified by two pairs of fluorescence labeled primers aiming at 16S rRNA gene and 16S-23S rRNA spacer region gene respectively at the same time. PCR products were then digested by restriction endonuclease HaeⅢ incompletely before taking capillary electrophoresis. The results with the PCR-CE-RFLP patterns of 16S rRNA genes were just alike within some genera, but when it comes to 16S-23S rRNA spacer region genes, each bacterium showed a unique pattern, which can be distinguished from each other easily. It seems that PCR-CE-RFLP patterns of 16S rRNA gene could only be used to classify the bacteria into family level, whereas the data of 16S-23S rRNA spacer region gene could be utilized to identify the whole microorganisms as precisely as the species level. In spite of the data of the spacer region gene alone can be sufficiently to verify the whole bacteria, we insist that the 16S rRNA gene could be of some assistant in case that there should be lots of families of bacteria, in which some similar ones, with the same RFLP data of 16S-23S rRNA spacer region gene, may coexist. This study proves that the utility of PCR-CE-RFLP is a convenient, rapid method to identify pathogenic bacteria, and is also a quick diagnosis measure for application to clinical use.
基金Supported by 863 Projects (2008AA10Z311)National Science and Technology Support Projects (2009BADB9B06)+1 种基金Started Post-doctoral Research Grant of Heilongjiang Province (LBH-Q07023)Harbin Technological Innovation of Special Funds (2007RFQXN020)
文摘According to the sequence of the bile salt hydrolase （BSH） gene of Bifidobacterium and the restriction enzyme cutting sites of expression vector pNZ8148, primers were designed and the bile salt hydrolase （BSH） gene was gotten from Bacillus bifidus ATCC 29521 by PCR. BSH gene was inserted into lactic acid bacteria expression vector pNZ8148 to construct the recombinant pNZ8148-BSH. The recombinant pNZ8148-BSH was transferred into lactic acid bacteria NZ9000 with electrotransformation method. And the recombinant which could express BSH protein was obtained. It was identified by SDS-PAGE electrophoresis and activity verification. The result could provide a rationale reference for expressing BSH in lactic acid bacteria.
文摘Cultured Apostichopus japonicus in China suffers from a kind of skin ulceration disease that has caused severe economic loss in recent years. The disease,pathogens of which are supposed to be bacteria by most researchers,is highly infectious and can often cause all individuals in the same culture pool to die in a very short time. The 16S rRNA gene phylogenesis of the culturable bacteria from the lesions of diseased individuals was conducted to study the biodiversity of the bacterial communities in the lesions and to identify probable pathogen(s) associated with this kind of disease. S. japonica samples were selected from a hatchery located in the eastern part of Qingdao,China. Bacterial universal primers GM5F and DS907R were used to amplify the 16S rRNA gene of bacteria colonies,and touchdown PCR was performed to amplify the target sequences. The results suggest that γ-proteobacteria(Alteromonadales and Vibrionales) of CFB group,many strains of which have been also determined as pathogens in other marine species,are the predominant bacterial genera of the diseased Apostichopus japonicus individuals.
基金The National Natural Science Foundation of China under contract No.41076131the Youth Marine Science Foundation of State Oceanic Administration under contract No.2011104+3 种基金the Public Science and Technology Research Funds Projects of Ocean under contract No.201105022the Chinese Polar Environment Comprehensive Investigation and Assessment Program under contract No.CHINARE2012-02-01the National High-Tech Research and Development Program of China under contract No.2012AA021706supports for SH Lee were provided by grants for the Polar Academic Program(PAP)and Korea Polar Research Institute(KOPRI)under contract No.PM11080
文摘Planktonic bacteria are abundant in the Chukchi Borderland region. However, little is known about their di- versity and the roles of various bacteria in the ocean. Seawater samples were collected from two stations K2S and K4S where sea ice was melting obviously. The analysis of water samples with fluorescence in situ hybridization （FISH） showed that DMSP-degrading bacteria accounted for 13% of the total bacteria at the station K2S. No aerobic anoxygenic phototrophic （AAP） bacteria were detected in both samples. The bacterial communities were characterized by two 16S rRNA gene clone libraries. Sequences fell into four major lineages of the domain Bacteria, including Proteobacteria （Alpha, Beta and Gamma subclasses）, Bac- teroidetes, Actinobacteria and Firmicutes. No significant difference was found between the two clone li- braries. SAR11 and Rhodobacteraceae clades of Alphaproteobacteria and Pseudoalteromonas of Gammapro- teobacteria constituted three dominant fractions in the clone libraries. A total of 191 heterotrophic bacterial strains were isolated and 76% showed extracellular proteolytic activity. Phylogenetic analysis reveals that the isolates fell into Gammaproteobacteria, Bacteroidetes, Actinobacteria and Firmicutes. The most common genus in both the bacterial isolates and protease-producing bacteria was Pseudoalteromonas. UniFrac data showed suggestive differences in bacterial communities between the Chukchi Borderland and the northern Bering Sea.
基金supported by the grants from the Genetically Modified Organisms Breeding Major Projects, China (2014ZX0800905B)the Fundamental Research Funds for the Central Universities, Chinathe Program for New Century 151 Talents of Zhejiang Province, China
文摘Phenazines are secondary metabolites with broad spectrum antibiotic activity and thus show high potential in biological control of pathogens. In this study, we identified phenazine biosynthesis （phz） genes in two genome-completed plant pathogenic bacteria Pseudomonas syringae pv. tomato （Pst） DC3000 and Xanthomonas oryzae pv. oryzae （Xoo） PXO99A. Unlike the phz genes in typical phenazine-producing pseudomonads, phz homologs in Pst DC3000 and Xoo PXO99A consisted of phzC/D/E/F/G and phzC/E1/E2/F/G, respectively, and the both were not organized into an operon. Detection experiments demonstrated that phenazine-l-carboxylic acid （PCA） of Pst DC3000 accumulated to 13.4 IJg L-1, while that of Xoo PXO99A was almost undetectable. Moreover, Pst DC3000 was resistant to 1 mg mL-1 PCA, while Xoo PXO99A was sensitive to 50 IJg mL ~ PCA. Furthermore, mutation of phzF blocked the PCA production and significantly reduced the pathogenicity of Pst DC3000 in tomato, while the complementary strains restored these phenotypes. These results revealed that Pst DC3000 produces low level of and is resistant to phenazines and thus is unable to be biologically controlled by phenazines. Additionally, phz-mediated PCA production is required for full pathogenicity of Pst DC3000. To our knowledge, this is the first report of PCA production and its function in pathogenicity of a plant pathogenic P. syringae strain.
文摘[Objective] Marine sediment from Tianjin Port has a extremely high salinity.The bacteria which live in such habitats have evolved distinct physiological,metabolic,and morphological characteristics to survive.The objective of this study is to identify all the specific salt-tolerant characteristics and the genetic evolution of the bacteria in the sediment.[Methods] In this study,the total DNA of sediment from Tianjin Port was extracted,and 16S rDNA was used to conduct an analysis of the fauna of sediment bacteria. We also isolated sediment bacteria using beef extract-peptone media with seven different NaCl concentrations (0,0.5%,2%,5%,10%,15%,and 20%),aiming to analyze the dominant species of halophilous bacteria under different salinities.[Results] 1) With each stepwise increase of salinity from 0.5% to 20%,the total number of isolated bacterial colonies decreased.14 strains of bacteria were identified and classified by the16S rDNA sequencing analysis.Of these,four could tolerate 0~2% salinity,four could tolerate 0~5% salinity,one could tolerate 0~15% salinity,and one tolerated within the full 0~20% salinity range.Further four strains were only able to tolerate within a few narrow salinity ranges.such as 5%~10%,10%~15%,10%~20% and 15%~20%;2) The quantity of bacteria strains that can be isolated from the marine sediment decreased with the increase of salinity. Also, the Shannon wiener index and species richness index of marine sediment bacteria decreased significantly from 5% salinity.However,there were no significant differences in the species evenness index;3) When the salinity was 0~10%,the dominant species was Bacillus.When the salinity was 15%, Halomonas was the dominant species.When the salinity was 20%,there were no significant differences in the proportions of these species.[Conclusion] Our results showed that some bacteria could tolerate living conditions with high salinity,and we even found a species which can tolerate a wide range of salinities (0~20%).In further study,it would be valuable to analyze these bacteria's unique physiological and biochemical functions that allow them to adapt to environments with high salinity.It can provide theories to promote the development of microbial population resources in marine sediment and the reclaimation of salinized soil by salt tolerant microorganisms.
基金The National Key Basic Research Special Foundation of China under contract No.2017YFC1404500the National Natural Science Foundation of China under contract No.41676115
文摘This study investigated differences in the community structure and environmental responses of the bacterial community in sediments of the Bohai Sea.Illumina high-throughput sequencing technology and real-time PCR were used to assay the bacterial 16S rRNA genes in the surface sediments of 13 sampling stations in the Bohai Sea.The results showed that sediments at the majority of the 13 sampling stations were contaminated by heavy metal mercury.The main phyla of bacteria recorded included Proteobacteria(52.92%),Bacteroidetes(11.76%),Planctomycetes(7.39%),Acidobacteria(6.53%)and Chloroflexi(4.97%).The genus with the highest relative abundance was Desulfobulbus(4.99%),which was the dominant genus at most sampling stations,followed by Lutimonas and Halioglobus.The main factors influencing bacterial community structure were total organic carbon,followed by depth and total phosphorus.The content of lead,cadmium,chromium,copper and zinc had a consistent effect on community structure.Arsenic showed a negative correlation with bacterial community structure in most samples,while the impact of mercury on community structure was not significant.The bacterial community in sediment samples from the Bohai Sea was rich in diversity and displayed an increase in diversity from high to low latitudes.The data indicated that the Bohai Sea had abundant microbial resources and was rich in bacteria with the potential to metabolize many types of pollutants.
基金supported by the Higher Institution Centre of Excellence(HiCoE)Research Grant(Grant No.6369105)。
文摘Improved rice lines were developed frome three parents with the resistance or tolerance to bacterial leaf blight,blast and drought stress,respectively,using single-,double-and three-way crosses.The improved lines were assessed for agro-morphological and yield traits under non-drought stress(NS)and reproductive-stage drought stress(RS)treatments.The mean comparison of traits measured between parent plants and progenies(improved lines)were similar,and there were significant and non-significant differences among the parents and improved lines(genotypes)under NS and RS.Smilarly,there was significant and non-significant differences in the interaction among both parent varieties and improved lines for NS and RS.Cluster and 3D-model of principal component analysis did not generate categorical clusters according to crossing methods,and there were no exclusive crossing method inclined variations under the treatments.The improved lines were high-yielding,disease resistant,and drought-tolerant compared with their parents.All the crossing methods were good for this crop improvement program without preference to any,despite the number of genes introgressed.
基金Project supported by the Shandong Provincial Natural Science Foundation,China(Grant No.ZR2014FM022)
文摘Essential genes are indispensable for the survival of an organism in optimal conditions.Rapid and accurate identifications of new essential genes are of great theoretical and practical significance.Exploring features with predictive power is fundamental for this.Here,we calculate six fractal features from primary gene and protein sequences and then explore their relationship with gene essentiality by statistical analysis and machine learning-based methods.The models are applied to all the currently available identified genes in 27 bacteria from the database of essential genes（DEG）.It is found that the fractal features of essential genes generally differ from those of non-essential genes.The fractal features are used to ascertain the parameters of two machine learning classifiers：Na¨？ve Bayes and Random Forest.The area under the curve（AUC） of both classifiers show that each fractal feature is satisfactorily discriminative between essential genes and non-essential genes individually.And,although significant correlations exist among fractal features,gene essentiality can also be reliably predicted by various combinations of them.Thus,the fractal features analyzed in our study can be used not only to construct a good essentiality classifier alone,but also to be significant contributors for computational tools identifying essential genes.
文摘This study was conducted to evaluate the influence of wastewater treatment processes on the prevalence of antibiotic resistance fecal coliform (FC) and antibiotic resistance genes (ARGs) of FC. In addition, the occurrence of antibiotic resistant bacteria (ARB) and antibiotic resistant genes (ARGs) in surface waters receiving wastewater was evaluated. Greater resistance against penicillin (P), colisitin (CT) and ampicillin (AMP) were observed for FC isolated from effluent disinfected by chlorine (71%), than that disinfected by UV (45%). The greatest resistance against six antibiotics was recorded for FC isolates from effluent disinfected by chlorine. The prevalence of tetB and blaSHV was lowest in isolates from chlorine-disinfected effluents. The occurrence of ARG blaSHV was highest in FC isolated from effluent disinfected by UV. A significant correlation was recorded between FC levels in surface waters and the level of bacterial resistance to ampicillin (P SHV in effluents and in surface waters. TetA and tetC were highly prevalent in surface water compared to tetB. The results of the study demonstrate the widespread prevalence of ARB and ARG in wastewater and receiving water bodies. The result indicates that the source of ARB and ARG in surface waters originate from wastewater. Released ARB and ARG may serve as the source of ARG to pathogenic bacteria in surface waters. Disinfection processes may influence the selection of antibiotic resistant patterns of bacteria.
