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Green tide is a harmful ecological phenomenon caused by the explosive proliferation or high aggregation of certain large green algae (such as Ulva prolifera) in seawater under specific environmental conditions, leading to discoloration of the water. The green tide formed by a large number of floating algae can not be effectively disposed of in a short period of time, which will lead to the accumulation and decay of green algae, thereby affecting the coastal ecological landscape. The outbreak of U. prolifera has been one of the main causes of green tide occurrences in the Yellow Sea since 2008. U. prolifera is an algal plant belonging to the family Ulvaceae, which has the characteristics of high nutrient absorption efficiency, fast growth rate and strong reproductive ability, and is more competitive than other species. The explosive proliferation of a large number of U. prolifera during a short period of time has a serious impact on marine environmental ecology, aquaculture, tourism and public health and safety. The study mainly investigated the environmental physicochemical parameters, cultivable microorganisms, dominant culture bacteria, and virulence and resistance genes of dominant bacteria in water and algae samples collected before and after the outbreak of U. prolifera in the main coastal areas of Qingdao were investigated. Environmental physicochemical factors, including the coliform and fecal coliform contents, chemical oxygen demand (COD), biochemical oxygen demand (BOD5), ammonia nitrogen (NH3-N) levels, nitrite, active phosphate, inorganic nitrogen, cyanide, sulfide, arsenic, mercury, copper, zinc, selenium, total chromium, nickel, cadmium, and lead ion levels, in the seawater were assessed. At the same time, the levels of organic carbon, sulfides, coliforms, fecal coliforms, and mercury, arsenic, cadmium, lead, zinc, copper, and chromium ions in the algae were measured. Research on cultivable microorganisms included an assessment of the abundance and composition of cultivable bacteria and Vibrio species in seawater and algae. The distribution of common virulence genes (VAC, vhh, chxA, tlh, and flaA) and resistance genes (strA, strB, QnrVC, and sul2) in the dominant Vibrio bacteria was examined to evaluate the potential virulence risk of the dominant Vibrio bacteria. Comparative analysis results showed that after the outbreak of U. prolifera, the COD, NH3-N, inorganic nitrogen, arsenic ion, and active phosphate levels in the coastal waters of Qingdao increased significantly (P < 0.05), and the levels of dissolved oxygen and cadmium, lead, chromium, copper, and other metal ions decreased significantly (P < 0.05). The organic carbon content in the algal samples from the aggregated areas of U. prolifera was lower than that from non-aggregated areas. In contrast, the content of coliforms, fecal coliforms, sulfide, mercury, cadmium, zinc, and copper ions significantly increased compared to that in open areas (P < 0.05). Moreover, the proportion of Vibrio bacteria increased from 7% to 45%, representing an increase of 38%. The bacterial identification results based on 16S rDNA showed that before the outbreak of U. prolifera, there were 79 dominant bacterial and 62 Vibrio strains in the coastal waters and algae bodies of Qingdao, belonging to 22 species. The main Vibrio species were V. gigantis, V. tasmaniensis, and V. atlanticus. After the outbreak of U. prolifera, 79 dominant bacterial and 65 Vibrio strains were isolated, belonging to 24 species, with the main Vibrio species being V. fortis, V. alginolyticus, and V. owensii. The distribution of virulence genes (VAC, vhh, chxA, tlh, and flaA) and resistance genes (strA, strB, QnrVC, and sul2) in dominant Vibrio bacteria isolated from water bodies and algae before and after the outbreak of U. prolifera was tested. The results showed that only two virulence genes, tlh and flaA, were detected before the outbreak of U. prolifera, and no resistance genes were detected. Five virulence genes and four resistance genes were identified after the outbreak of U. prolifera. Correlation analysis between the number of cultivable bacteria and the environmental physicochemical factors in the water and algae of Qingdao coastal waters before and after the outbreak of U. prolifera showed that the abundance of cultivable bacteria and Vibrio species in the water and algae was correlated with environmental factors such as temperature, pH, NH3-N, nitrite, inorganic nitrogen, active phosphate, total chromium, and nickel. The results revealed the impact of the outbreak of U. prolifera on the bacterial community structure and environmental ecology in the coastal environment of Qingdao. At the same time, the harmful microbial species caused by the outbreak of U. prolifera and the risk of virulence genes and drug resistance genes carried by the outbreak of U. prolifera were evaluated. The relevant research results provide a theoretical basis for the prevention and control of green tide, marine ecological protection, healthy aquaculture in the coastal waters of the Yellow Sea and Bohai Sea.

Climate change leads to an increase in both the frequency and intensity of extreme precipitation. Surface runoff generated by extreme precipitation has a significant impact on water. However, the impact of persistent precipitation on surface water quality is easy to neglect, due to its prolonged duration and lower-intensity rainfall. This study established eight sampling points within selected surface waters to observe the variation of microbial characteristics in a typical persistence precipitation event. The primary difference between Furong Lake (FL) and Chengqian Reservoir (CR) was: the concentrations of dissolved organic carbon (DOC) were 21.3 ± 0.7 and 8.3 ± 1.5 mg/L in FL and CR, respectively. The concentrations of R2A culturable bacteria and coliforms were 104.57 and 101.58 colony-forming units (CFU)/mL in FL, and were 105.46 and 102.64 CFU/mL in CR, respectively. During precipitation, the maximum increase concentrations of R2A, NA culturable bacteria, and coliforms were 100.75, 101.30, and 102.27 CFU/mL in FL, respectively. Furthermore, microbial concentration and rainfall did not increase simultaneously, and a delay phenomenon was observed in the increasing microbial concentrations. Through analyzing the concentration change trends and correlation of various water quality indicators during persistent precipitation, the significant correlation between the DOC concentration and the changes in the dominant species of microbial community structure was found in this study (p < 0.05). For example, as the DOC concentration declined, the abundance of hgcl_clade and CL500-29_marine_group increased. Consequently, although persistent precipitation might not obviously alter the water quality visibly, it could still pose potential microbial risks. [ABSTRACT FROM AUTHOR]

Garcia et al. recently identified a novel myxobacterial family, Pendulisporaceae, encompassing four strains with novel biosynthetic gene clusters. This study underscores the value of exploring underrepresented microbial taxa for novel natural products, highlighting the potential of the family Pendulisporaceae as a source of new antimicrobial and therapeutic agents. [ABSTRACT FROM AUTHOR]

Copyright of Acta Agriculturae Zhejiangensis is the property of Acta Agriculturae Zhejiangensis Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Antibiotics are commonly used for controlling microbial growth in diseased organisms. However, antibiotic treatments during early developmental stages can have negative impacts on development and physiology that could offset the positive effects of reducing or eliminating pathogens. Similarly, antibiotics can shift the microbial community due to differential effectiveness on resistant and susceptible bacteria. Though antibiotic application does not typically result in mortality of marine invertebrates, little is known about the developmental and transcriptional effects. These sublethal effects could reduce the fitness of the host organism and lead to negative changes after removal of the antibiotics. Here, we quantify the impact of antibiotic treatment on development, gene expression, and the culturable bacterial community of a model cnidarian, Nematostella vectensis. Methods: Ampicillin, streptomycin, rifampicin, and neomycin were compared individually at two concentrations, 50 and 200 µg mL−1, and in combination at 50 µg mL−1 each, to assess their impact on N. vectensis. First, we determined the impact antibiotics have on larval development. Next Amplicon 16S rDNA gene sequencing was used to compare the culturable bacteria that persist after antibiotic treatment to determine how these treatments may differentially select against the native microbiome. Lastly, we determined how acute (3-day) and chronic (8-day) antibiotic treatments impact gene expression of adult anemones. Results: Under most exposures, the time of larval settlement extended as the concentration of antibiotics increased and had the longest delay of 3 days in the combination treatment. Culturable bacteria persisted through a majority of exposures where we identified 359 amplicon sequence variants (ASVs). The largest proportion of bacteria belonged to Gammaproteobacteria, and the most common ASVs were identified as Microbacterium and Vibrio. The acute antibiotic exposure resulted in differential expression of genes related to epigenetic mechanisms and neural processes, while constant application resulted in upregulation of chaperones and downregulation of mitochondrial genes when compared to controls. Gene Ontology analyses identified overall depletion of terms related to development and metabolism in both antibiotic treatments. Discussion: Antibiotics resulted in a significant increase to settlement time of N. vectensis larvae. Culturable bacterial species after antibiotic treatments were taxonomically diverse. Additionally, the transcriptional effects of antibiotics, and after their removal result in significant differences in gene expression that may impact the physiology of the anemone, which may include removal of bacterial signaling on anemone gene expression. Our research suggests that impacts of antibiotics beyond the reduction of bacteria may be important to consider when they are applied to aquatic invertebrates including reef building corals. [ABSTRACT FROM AUTHOR]

Seed endophytic bacteria and fungi are co-dispersed with seeds and are likely founders of the initial endophytic microbiome in developing seedlings. The effects of the seed microbiome on seedling survival and growth are of particular interest for their roles in protection against pathogens and plant resistance to environmental stress. The fungal pathogen Austropuccinia psidii (G. Winter) Beenken is the causal agent of myrtle rust, which infects more than 480 species of Myrtaceae globally and poses a severe threat to New Zealand endemic species such as Metrosideros excelsa Sol. ex Gaertn. We hypothesised that seedlings of M. excelsa may contain seed-derived microbial communities that may contribute to variation in susceptibility to A. psidii. Culture based methods were used to recover 22 species of fungi (n = 412 isolates) and 16 bacterial taxa (n = 156 isolates) from 1580 M. excelsa seeds collected from 30 trees. Our results indicate broad variation in the isolation frequency and species composition of seed-borne microorganisms among individual trees: while seeds sampled from four trees were free of culturable microorganisms, the other 26 trees accumulated up to eight culturable taxa (both bacteria and fungi) in their seeds, including some species known to be beneficial endophytes or phytopathogens. The most frequently isolated fungal species belong to genera Aureobasidium, Cladosporium, Penicillium, and Pestalotiopsis. These fungi were often isolated from seeds also containing bacteria of the genera Bacillus, Erwinia, and Methylobacterium. At the same time, seeds collected from four trees contained known plant pathogens Colletotrichum aff. fioriniae (Marcelino & Gouli) Pennycook, Neofusicoccum sp., and Robbsia aff. andropogonis (Smith) Lopes-Santos et al., which could affect seed germination. This is the first report of bacterial and fungal communities residing in seeds of endemic New Zealand trees and the potential effects of seed-borne microbiomes on germination. [ABSTRACT FROM AUTHOR]

Aphids shelter several bacteria that benefit them in various ways. The associates having an obligatory relationship are non-culturable, while a few of facultative associates are culturable in insect cell lines, axenic media or standard microbiology media. In the present investigation, isolation, and characterization of the culturable bacterial associates of various aphid species, viz., Rhopalosiphum maidis, Rhopalosiphum padi, Sitobion avenae, Schizaphis graminum, and Lipaphis erysimi pseudobrassicae were carried out. A total of 42 isolates were isolated using different growth media, followed by their morphological, biochemical, and molecular characterization. The isolated culturable bacterial associates were found to belong to the genera Acinetobacter, Bacillus, Brevundimonas, Cytobacillus, Fictibacillus, Planococcus, Priestia, Pseudomonas, Staphylococcus, Sutcliffiella, and Tumebacillus which were grouped under seven families of four different orders of phyla Bacillota (Firmicutes) and Pseudomonata (Proteobacteria). Symbiont–entomopathogen interaction study was also conducted, in which the quantification of colony forming units of culturable bacterial associates of entomopathogenic fungal-treated aphids led us to the assumption that the bacterial load in aphid body can be altered by the application of entomopathogens. Whereas, the mycelial growth of entomopathogens Akanthomyces lecanii and Metarhizium anisopliae was found uninhibited by the bacterial associates obtained from Sitobion avenae and Rhopalosiphum padi. Analyzing persistent aphid microflora and their interactions with entomopathogens enhances our understanding of aphid resistance. It also fosters the development of innovative solutions for agricultural pest management, highlighting the intricate dynamics of symbiotic relationships in pest management strategies. [ABSTRACT FROM AUTHOR]

The biological complexity of leaf‐cutting ants is determined in part by both positive and negative associations with microorganisms. These ants constantly face microorganisms that can compromise workers' survival and the integrity of their symbiont fungus. The ability to produce antimicrobial compounds within the colony, both by the workers and by associated microorganisms, is an adaptive response that protects against these natural enemies. Atta cephalotes (Linnaeus, 1758) is an ecologically successful species with a great capacity to overcome pathogenic microorganisms. In contrast to the Acromyrmex genus, the evidence suggests that it does not maintain an association with antibiotic‐producing actinobacteria raising the question of whether this species maintains associations with bacterial communities that can potentially protect the colony against prejudicial microorganisms. In this direction, the diversity and composition of the culturable bacterial microbiota associated with A. cephalotes developmental stages were evaluated, as well as their potential to inhibit the growth of the entomopathogenic fungus Metarhizium anisopliae and the mycoparasite Trichoderma sp. Six nests were collected, of which a total of 900 larvae, 900 pupae and 900 adult workers were analysed. Culture‐dependent and molecular methods were used to identify the strains to genus level. To determine differences in bacterial composition in the development stages, analysis of the contribution to dissimilarity (SIMPER) were performed. Seventy‐seven strains corresponding to 18 genera were documented. Acinetobacter was the dominant one. On the other hand, Acinetobacter, Bacillus, Enterobacter, Serratia and Microbacterium were maintained from the larval to the adult stage. Furthermore, except for Acinetobacter, different strains of these bacterial groups significantly inhibited pathogenic fungi growth. The results suggest the existence of a persistent association of A. cephalotes with strains of these bacterial genera and a potential role in defence at the collective level. [ABSTRACT FROM AUTHOR]

Background Antibiotics are commonly used for controlling microbial growth in diseased organisms. However, antibiotic treatments during early developmental stages can have negative impacts on development and physiology that could offset the positive effects of reducing or eliminating pathogens. Similarly, antibiotics can shift the microbial community due to differential effectiveness on resistant and susceptible bacteria. Though antibiotic application does not typically result in mortality of marine invertebrates, little is known about the developmental and transcriptional effects. These sublethal effects could reduce the fitness of the host organism and lead to negative changes after removal of the antibiotics. Here, we quantify the impact of antibiotic treatment on development, gene expression, and the culturable bacterial community of a model cnidarian, Nematostella vectensis. Methods Ampicillin, streptomycin, rifampicin, and neomycin were compared individually at two concentrations, 50 and 200 µg mL−1, and in combination at 50 µg mL−1 each, to assess their impact on N. vectensis. First, we determined the impact antibiotics have on larval development. Next Amplicon 16S rDNA gene sequencing was used to compare the culturable bacteria that persist after antibiotic treatment to determine how these treatments may differentially select against the native microbiome. Lastly, we determined how acute (3-day) and chronic (8-day) antibiotic treatments impact gene expression of adult anemones. Results Under most exposures, the time of larval settlement extended as the concentration of antibiotics increased and had the longest delay of 3 days in the combination treatment. Culturable bacteria persisted through a majority of exposures where we identified 359 amplicon sequence variants (ASVs). The largest proportion of bacteria belonged to Gammaproteobacteria, and the most common ASVs were identified as Microbacterium and Vibrio. The acute antibiotic exposure resulted in differential expression of genes related to epigenetic mechanisms and neural processes, while constant application resulted in upregulation of chaperones and downregulation of mitochondrial genes when compared to controls. Gene Ontology analyses identified overall depletion of terms related to development and metabolism in both antibiotic treatments. Discussion Antibiotics resulted in a significant increase to settlement time of N. vectensis larvae. Culturable bacterial species after antibiotic treatments were taxonomically diverse. Additionally, the transcriptional effects of antibiotics, and after their removal result in significant differences in gene expression that may impact the physiology of the anemone, which may include removal of bacterial signaling on anemone gene expression. Our research suggests that impacts of antibiotics beyond the reduction of bacteria may be important to consider when they are applied to aquatic invertebrates including reef building corals.

Introduction: Sea urchin aquaculture is a rising industry, and in consequence, there is a need to establish optimal culture parameters to ensure the health of the cultured animals. Objective: To evaluate the bacterial counts in the seawater of sea urchin (Arbacia dufresnii) aquaculture recirculating systems (RAS). Methods: The bacteriological water quality of two RAS containing sea urchins was determined. For approximately two months, weekly water samples were taken. The bacteriological quality was determined by counting total aerobic heterotrophic populations, lactic acid bacteria, enterobacterias and genus Vibrio. Physicochemical parameters were also measured. Results: There was no presence of disease or mortality. Enterobacteria and lactic acid bacteria were not detected from both RAS systems. The number of animals had an important effect on the observed difference in the count of total bacteria and Vibrio spp. In RAS 1 the maximum counts of total bacteria and Vibrio spp. were 2.8 x 105 ± 1.7 x 105 and 1.45 x 105 ± 3.6 x 104 UFC ml-1, respectively. In RAS 2 total bacteria and Vibrio spp. exhibited repetitive behavior over time influenced in part by water exchange and mainly by feeding. The results indicate that periodic water changes ensure a limited growth of bacterial strains as Vibrio and other bacteria. Conclusions: Our results suggests that the bacterial count levels recorded in this study can be used as a threshold or safety limit for Arbacia dufresnii aquaculture. [ABSTRACT FROM AUTHOR]

Marine microorganisms have evolved special metabolic pathways to produce numerous bioactive substances with novel structures and unique functions. This study analyzed the diversity of culturable bacteria in marine water samples from the South China Sea and screened the isolated bacteria with pathogenic fungi. A total of 200 culturable strains of 72 different bacteria were obtained from 56 water samples from the South China Sea. They belonged to three phyla and four classes, namely Gammaproteobacteria, Alphaproteobacteria, Bacilli and Actinomycetia. Bacilli was the dominant class, comprising up to 59.72%, followed by Gammaproteobacteria (20.83%). Bacillus, Pseudomonas, Paenibacillus and Rhizobium were the most dominant genera. Among these strains, HY-88 and HY-91 encoding BamC, FenB and PKSI genes were selected and identified as Bacillus subtilis. The respective inhibition rates of the HY-88 caused by plate confrontation against Magnaporthe grisea, Fusarium oxysporum, Botrytis cinerea, anthrax and Botrytis cinerea were 90.91%, 54.29%, 52.17% and 51.72%, in comparison with HY-91 86.36%, 48.57%, 47.83% and 34.48%. In addition, the supernatant of HY-88 showed a lesion inhibition rate of 74.5%, which was significantly higher than HY-91 (60.55%). In addition, HY-88 and HY-91 showed strong antifungal activity to Colletotrichum viniferum on detached Shine Muscat grapes. Tolerance tests showed that the HY-88 and HY-91 grew at 10–40 °C, 7–10% NaCl and pH 3-11. HY-88 and HY-91 could inhibit various fungal plant diseases, which lays a foundation for the development of new biopesticides. [ABSTRACT FROM AUTHOR]

[Objective] To investigate the diversity of culturable bacteria associated with kiwifruit rhizosphere soils in western Hunan and to isolate antagonistic strains of Kiwifruit canker disease bacteria. [Method] Bacteria (including actinomycetes) were isolated from the samples using the pure culture method, and the biodiversity of these isolates was studied by phylogenetic analysis based on 16S rRNA gene sequences. The antagonistic strains were then screened using the Oxford cup method. [Result] 142 strains were isolated from the rhizosphere soil of kiwifruit, and by 16S rRNA gene sequence analysis, the 142 strains belonged to 4 phyla, 6 class, 11 orders, 18 families, and 28 genera. Bacillus is the dominant genus. And 4 strains（A11,D1h, A4,B15） with antagonistic effect on kiwifruit canker disease bacterium were screened out from them. After phylogenetic analysis, it was tentatively determined that A11 and D1h belonged to Rhodococcus,A4 belonged to Bacillus, and B15 belonged to Streptomyces. [Conclusion] Kiwifruit rhizosphere soils are rich in species and genetic diversity of culturable bacteria and the presence of microbial taxa antagonistic to kiwifruit canker disease bacterium. [ABSTRACT FROM AUTHOR]

Improving the availability of new sources of probiotics is essential to continue implementing alternative solutions to improve coral health; one such source is urban corals. However, little is known about urban coral's health status and whether they can harbor bacteria exhibiting probiotic traits. Here, we explored the status of the urban coral Madracis auretenra and the presence of probiotic traits in its associated culturable bacteria. After assessing ecological attributes, we observed a similar abundance (cover %) when comparing patches of M. auretenra occurring in both an urban site and a marine protected area. The urban patch also exhibited a high abundance of vibrios in coral tissues and signs of ecosystem deterioration. However, this patch showed a "good" health index condition; so, we hypothesized the presence of beneficial bacteria. We isolated 132 bacterial strains from this healthy urban M. auretenra. These bacteria were affiliated with 11 genera, including Vibrio, Shewanella, Bacillus, Exiguobacterium, Priestia, and Niallia, among others. Screenings revealed the predominant presence of potential probiotic traits such as catalase, antiQS, and the production of siderophores activities among the bacterial isolates. We proposed a list of 24 bacterial isolates as probiotic precandidates that jointly exhibited three or more of these traits, among which the Vibrio and Bacilli strains stand out. We provide insights into the health status of this urban coral and its potential as a source of bacteria exhibiting potential probiotic traits. [ABSTRACT FROM AUTHOR]

Ecosystems away from human disturbance provide an ideal paradigm for microbial ecology research. The Burqin glacier No. 18 in the Chinese Altay Mountains is such an ecosystem; however, there are no prior studies on the microbiology in the area. Here, we isolated 902 bacterial strains on the Burqin glacier No. 18 to determine the diversity and distribution characteristics of microorganisms. Isolated strains belonged to six phyla (in the order of dominance: Proteobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria, Firmicutes, and Deinococcus-Thermus) and 90 genera. Our results also demonstrated the presence of a high proportion of potential new species (43%) in the Burqin glacier No. 18, and 67% of the potential new species were isolated at 25 °C. Species diversity varied among habitats, with the lowest diversity in surface ice and the highest diversity in the soil farthest from the glacier terminus. The pigmented colonies made up 52.7% of all isolates, with yellow-colored colonies being the most abundant (18.8%). This study indicates that the Burqin glacier No. 18 hosts rich bacterial strain diversity, and may represent a significant potential source of new functional and pigmented bacteria for the development of critical pharmaceuticals. [ABSTRACT FROM AUTHOR]

Acanthus ebracteatus is a special kind of rare mangrove plant, possessing great medicinal value. In this paper, in order to study the diversity of endophytic and rhizosphere culturable bacteria in the A. ebracteatus, we explored new potential bacterial species and strains with special biological activities. The culturable bacteria were isolated from A. ebracteatus by dilution separation method. The bacterial diversity was investigated based on the 16S rRNA gene sequence analysis. In addition, the confrontation experiment and lawn predation assay were utilized to screen bacteria with anti-microorganism activities. The results were as follows: (1) A total of 144 culturable bacteria were isolated from A. ebracteatus root, stems, leaves, flowers and rhizosphere soil. These bacteria were affiliated into 66 species based on the analysis of the 16S rRNA gene sequence. The bacterial genera Bacillus and Streptomyces were dominant in plant tissue and rhizosphere soil with that of the value 15.1% and 13.6%, respectively. (2) The bioactivity assays revealed that there were 29 strains with anti-fungal activity and 10 strain possessing a broad spectrum of anti-fungal activity. Among them, the Streptomyces strains had the strongest antagonistic effect, and the active strain Y129 was a potential new species. (3) A total of five strains showed predation activity on Staphylococcus aureus, multi-drug resistance Staphylococcus aureus and Escherichia coli. Pseudomonas had the strongest predatory activity, and the active strain Y90 was a potential new species. In conclusion, A. ebracteatus and their rhizosphere soil contain rich bacterial germplasm resources and have a variety of functional strains, which can be used as one of the sources of biocontrol bacteria and medicinal bacteria. This study provides the theoretical reference for improving the efficacy and cultivation of A. ebracteatus.

Mangrove habitat is rich in microbial flora and its secondary metabolites have novel structure, which is an important source for mining new drugs. This study preliminarily evaluated the culturable bacterial diversity of sediments, roots, leaves and hypocotyls of Bruguiera gymnorhiza and the biological activity of bacterial metabolites, and looked for anti-HBV drug source strains. Pure culture technique and 16S rRNA molecular biology technique were employed to determine the species of bacteria and analyze the species diversity. Using HepG2.2.15 cell line as a model, the anti-HBV activity of bacterial metabolites was tested by MTT and PCR techniques. The secondary metabolites of active bacteria were preliminary analyzed by LC-HRMS technique. The results were as follows: (1) A total of 59 species of bacteria were obtained, belonging to 4 phyla, 5 classes, 14 orders, 23 families, and 36 genera, among which Bacillus was the dominant genus. Strains GXIMD07402, GXIMD07665 and GXIMD07384 were potential new species of Pseudooceanicola, Thioclava and Aestuariibaculum, respectively. (2) The results of anti-HBV activity showed that GXIMD07366, GXIMD07616, GXIMD07384, GXIMD07550 and GXIMD07445X could significantly reduce the level of HBV DNA in the supernatant of HepG2.2.15 cells (P

Abstract Background Populus euphratica Olivier is a kind of tree capable of growing in extremely arid desert and semi-desert environments. In this study, a culture-dependent method was used to analyze the bacterial diversity of stem liquid of P. euphratica and resina of P. euphratica, and to further evaluate plant growth promoting (PGP) activity. Results A total of 434 bacteria were isolated from stem fluid and resina of P. euphratica in Ebinur Lake Wetland Nature Reserve and Mulei Primitive forest. The results of taxonomic composition analysis shows that Gammaproteobacteria, Firmicutes, and Actinobacteria_c are the three dominant groups in all the communities, and the representative genera are Bacillus, Nesterenkonia and Halomonas. The diversity analysis shows that the culturable bacterial community diversity of P. euphratica in Ebinur Lake Wetland Nature Reserve is higher than that in Mulei Primitive forest, and the bacterial community diversity of P. euphratica stem fluid is higher than that of resina. According to PGP activity evaluation, 158 functional bacteria with plant growth promoting potential were screened. Among them, 61 strains havephosphorus solubilizing abilities, 80 strains have potassium solubilizing abilities, 32 strains have nitrogen fixation abilities, and 151 strains have iron ammonia salt utilization abilities. The germination rate, plant height, and dry weight of the maize seedlings treated with strains BB33-1, TC10 and RC6 are significantly higher than those of the control group. Conclusion In this study, a large number of culturable bacteria were isolated from P. euphratica, which provides new functional bacteria sources for promoting plant growth.

Special geographical location and abundant organic matter profiles in tidal flats have resulted in great microbial diversity, in which Bacteroidota strains are considered as one of the primary degraders of polysaccharides, playing a crucial role in the carbon cycle. In this study, we collected sediment or sand samples from 34 bare tidal flats in China and investigated the profile of culturable bacteria, selected three Bacteroidota for polyphasic taxonomic analysis and revealed their polysaccharide metabolic potential. Totally, we isolated 352 pure cultured bacteria and they mainly distributed in Bacteroidota, Pseudomonadota, Bacillota, and Actinomycetota. It is shown that the bare tidal flats contained a large number of potential novel species, mainly distributed in Flavobacteriales and Cytophagales within Bacteroidota. Three Bacteroidota strains, M17T, M82T, and M415T, isolated from mudflat were selected for polyphasic taxonomic analysis. The 16S rRNA gene sequence similarity between strain M17T and Mangrovivirga cuniculi KCTC 72349T was 99.28%, and less than 90.09% with other species; strain M82T shared the highest 16S rRNA gene sequence similarity of 97.85% with Pontibacter litorisediminis KCTC 52252T, and less than 97.43% with other species; strain M415T had higher 16S rRNA gene sequence similarities with type species of genera Eudoraea (92.62-93.68%), Zeaxanthinibacter (92.02-92.91%), and Muriicola (92.21-92.83%). Phylogenetic analysis based on 16S rRNA gene sequences and single-copy orthologous clusters showed that strains M17T and M82T represent novel species within the genus Mangrovivirga and Pontibacter, respectively, and strain M415T represents a novel species of a novel genus within the family Flavobacteriaceae. The potential in polysaccharide metabolism of all these three strains was analyzed by genomes. The analysis revealed that glycoside hydrolases and glycosyltransferases account for more than 70% of the total CAZymes. Additionally, the numbers of polysaccharide utilization loci (PULs) and annotated CAZymes in Cytophagales spp. M17T and M82T were found to be higher than those in Flavobacteriales sp. M415T. Highly specialized saccharolytic systems and the presence of numerous diversified CAZymes for obtaining energy through polysaccharide metabolism were speculated to help the three novel strains adapt to the utilization of both terrestrial and marine polysaccharides.

Simple Summary: Termites represent a unique and highly efficient system for lignocellulose bioconversion. The highly efficient lignocellulolytic systems are achieved through contributions from gut bacterial symbionts. Despite extensive research, the complete picture of bacterial diversity and their associated functions towards lignocellulose digestion by fungus-growing termite species is still lacking. In line with this objective, the present study revealed a diversity profile of cellulolytic and hemicellulolytic bacterial symbionts in the gut systems of some representative fungus-growing termites. The potential functions of the bacteria towards lignocellulose digestion, particularly cellulose and hemicellulose hydrolysis, were further identified and analyzed. The present investigation provided a unique profile of lignocellulose degrading symbiotic bacteria from the termites in general and fungus-growing species in particular. Fungus-growing termites are eusocial insects that represent one of the most efficient and unique systems for lignocellulose bioconversion, evolved from a sophisticated symbiosis with lignocellulolytic fungi and gut bacterial communities. Despite a plethora of information generated during the last century, some essential information on gut bacterial profiles and their unique contributions to wood digestion in some fungus-growing termites is still inadequate. Hence, using the culture-dependent approach, the present study aims to assess and compare the diversity of lignocellulose-degrading bacterial symbionts within the gut systems of three fungus-growing termites: Ancistrotermes pakistanicus, Odontotermes longignathus, and Macrotermes sp. A total of 32 bacterial species, belonging to 18 genera and 10 different families, were successfully isolated and identified from three fungus-growing termites using Avicel or xylan as the sole source of carbon. Enterobacteriaceae was the most dominant family represented by 68.1% of the total bacteria, followed by Yersiniaceae (10.6%) and Moraxellaceae (9%). Interestingly, five bacterial genera such as Enterobacter, Citrobacter, Acinetobacter, Trabulsiella, and Kluyvera were common among the tested termites, while the other bacteria demonstrated a termite-specific distribution. Further, the lignocellulolytic potential of selected bacterial strains was tested on agricultural waste to evaluate their capability for lignocellulose bioconversion. The highest substrate degradation was achieved with E. chengduensis MA11 which degraded 45.52% of rice straw. All of the potential strains showed endoglucanase, exoglucanase, and xylanase activities depicting a symbiotic role towards the lignocellulose digestion within the termite gut. The above results indicated that fungus-growing termites harbor a diverse array of bacterial symbionts that differ from species to species, which may play an inevitable role to enhance the degradation efficacy in lignocellulose decomposition. The present study further elaborates our knowledge about the termite-bacteria symbiosis for lignocellulose bioconversion which could be helpful to design a future biorefinery. [ABSTRACT FROM AUTHOR]

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Copyright of Guihaia is the property of Guihaia Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Marine microorganisms have evolved special metabolic pathways to produce numerous bioactive substances with novel structures and unique functions. This study analyzed the diversity of culturable bacteria in marine water samples from the South China Sea and screened the isolated bacteria with pathogenic fungi. A total of 200 culturable strains of 72 different bacteria were obtained from 56 water samples from the South China Sea. They belonged to three phyla and four classes, namely Gammaproteobacteria, Alphaproteobacteria, Bacilli and Actinomycetia. Bacilli was the dominant class, comprising up to 59.72%, followed by Gammaproteobacteria (20.83%). Bacillus, Pseudomonas, Paenibacillus and Rhizobium were the most dominant genera. Among these strains, HY-88 and HY-91 encoding BamC, FenB and PKSI genes were selected and identified as Bacillus subtilis. The respective inhibition rates of the HY-88 caused by plate confrontation against Magnaporthe grisea, Fusarium oxysporum, Botrytis cinerea, anthrax and Botrytis cinerea were 90.91%, 54.29%, 52.17% and 51.72%, in comparison with HY-91 86.36%, 48.57%, 47.83% and 34.48%. In addition, the supernatant of HY-88 showed a lesion inhibition rate of 74.5%, which was significantly higher than HY-91 (60.55%). In addition, HY-88 and HY-91 showed strong antifungal activity to Colletotrichum viniferum on detached Shine Muscat grapes. Tolerance tests showed that the HY-88 and HY-91 grew at 10–40 °C, 7–10% NaCl and pH 3-11. HY-88 and HY-91 could inhibit various fungal plant diseases, which lays a foundation for the development of new biopesticides.

【Objective】The study was carried out to investigate the effect of host switching on the diversity of intestinal bacteria in Batocera lineolata larvae, and find out the host adaptability of B. lineolata larvae from the perspective of intestinal bacteria, with a view to providing a theoretical basis for the development and utilization of microbes.【Method】B. lineolata larvae were raised with walnut as primary hosts and Eucalyptus as switching hosts, and the diversity of intestinal bacteria in B. lineolata larvae was studied by using the methods of traditional microbial culture, 16Sr RNA gene sequencing and high-throughput sequencing.【Result】A total of 19 culturable strains of bacteria were obtained through traditional microbial culture. 10 strains of bacteria were isolated from the intestine of the larvae of B. lineolata reared on the original host, and 9 strains were isolated from the larvae of B. reared by host; 6 genera of culturable bacteria were isolated from both treatments, 5 of which were common genera. High-throughput sequencing results showed that there were no significant differences in the diversity of intestinal bacteria in the larvae before and after host switching. B. lineolata larvae intestinal bacteria samples respectively belonged to 20 phylums, 32 classes, 55 orders, 90 families and 170 genera, including, under two treatments, both B.lineolata larvae gut dominant fungi belonging to the Proteobacteri, Gammaproteobacteria, Enterobacteriales, Enterobacteriaceae and Uncultured bacterium f Enterobacteriaceae.【Conclusion】The composition of intestinal bacteria species of B. lineolata larvae under two treatments was similar, the overall diversity of intestinal bacterial community was relatively rich and stable, and it was difficult to change the diversity of intestinal bacteria by changing the host in a short period of time.

Bacteria are an essential biotic component in freshwater environments. A group of 262 bacterial strains of freshwater environments from an altitudinal gradient in the Eastern Cordillera of Colombia was identified using the 16S rRNA gene sequence analysis. Hill numbers and related diversity indices were calculated to know the bacteria diversity in this collection and environments. In addition, the Bray–Curtis index was also calculated to know the differences in genera composition between sampled localities and their relationship with altitudinal gradient. The identified bacterial strains were grouped into 7 major phylogenetic groups (Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Flavobacteriia, Actinomycetes, Clostridia, and Bacilli), 38 genera, and 84 distinctive species. Diversity analysis based on Hill numbers showed that the diversity concerning bacteria inhabiting freshwater environments was consistently high. Dominant genera were Klebsiella, Serratia , and Pseudomonas , although other genera such as Bacillus, Lelliottia , and Obesumbacterium were well represented per locality. The highest bacterial diversity came from localities Cimitarra and El Carmen del Chucurí, while those originating from Santa Bárbara and Páramo del Almorzadero were relatively lower diverse. Differences in diversity were found to be mainly due to the spatial replacement of one genus by another and, to a lesser extent, to the loss or gain of taxa. [ABSTRACT FROM AUTHOR]

Background: Populus euphratica Olivier is a kind of tree capable of growing in extremely arid desert and semi-desert environments. In this study, a culture-dependent method was used to analyze the bacterial diversity of stem liquid of P. euphratica and resina of P. euphratica, and to further evaluate plant growth promoting (PGP) activity. Results: A total of 434 bacteria were isolated from stem fluid and resina of P. euphratica in Ebinur Lake Wetland Nature Reserve and Mulei Primitive forest. The results of taxonomic composition analysis shows that Gammaproteobacteria, Firmicutes, and Actinobacteria_c are the three dominant groups in all the communities, and the representative genera are Bacillus, Nesterenkonia and Halomonas. The diversity analysis shows that the culturable bacterial community diversity of P. euphratica in Ebinur Lake Wetland Nature Reserve is higher than that in Mulei Primitive forest, and the bacterial community diversity of P. euphratica stem fluid is higher than that of resina. According to PGP activity evaluation, 158 functional bacteria with plant growth promoting potential were screened. Among them, 61 strains havephosphorus solubilizing abilities, 80 strains have potassium solubilizing abilities, 32 strains have nitrogen fixation abilities, and 151 strains have iron ammonia salt utilization abilities. The germination rate, plant height, and dry weight of the maize seedlings treated with strains BB33-1, TC10 and RC6 are significantly higher than those of the control group. Conclusion: In this study, a large number of culturable bacteria were isolated from P. euphratica, which provides new functional bacteria sources for promoting plant growth. [ABSTRACT FROM AUTHOR]

Improving the availability of new sources of probiotics is essential to continue implementing alternative solutions to improve coral health; one such source is urban corals. However, little is known about urban coral’s health status and whether they can harbor bacteria exhibiting probiotic traits. Here, we explored the status of the urban coral Madracis auretenra and the presence of probiotic traits in its associated culturable bacteria. After assessing ecological attributes, we observed a similar abundance (cover %) when comparing patches of M. auretenra occurring in both an urban site and a marine protected area. The urban patch also exhibited a high abundance of vibrios in coral tissues and signs of ecosystem deterioration. However, this patch showed a “good” health index condition; so, we hypothesized the presence of beneficial bacteria. We isolated 132 bacterial strains from this healthy urban M. auretenra. These bacteria were affiliated with 11 genera, including Vibrio, Shewanella, Bacillus, Exiguobacterium, Priestia, and Niallia, among others. Screenings revealed the predominant presence of potential probiotic traits such as catalase, antiQS, and the production of siderophores activities among the bacterial isolates. We proposed a list of 24 bacterial isolates as probiotic precandidates that jointly exhibited three or more of these traits, among which the Vibrio and Bacilli strains stand out. We provide insights into the health status of this urban coral and its potential as a source of bacteria exhibiting potential probiotic traits.

The results of the study on the characteristics of the viable (culturable) and total bacterial particles in the ambient air in Gliwice, Poland, are presented. The concentration of viable bacteria in the air ranged from 57 CFU m−3 (Colony Forming Units per cubic meter) during winter to 305 CFU m−3 in spring, while the concentration of all bacteria (live and dead) in the air, measured in selected days, ranged from 298 cells m−3 in winter to over 25 thousand per m3 in autumn. A field study was also carried out to find out the level of the sterilization rate (k) for airborne bacteria. The obtained value of k for viable bacteria exposed to UV solar radiation in Gliwice was approximately 10 cm2 W−1s−1. The patterns of the size distributions of viable bacteria found in three seasons, spring, summer, and autumn, were similar, showing a peak in the range of 3.3–4.7 µm. In the winter season, the main peak was shifted into the smaller particles with an aerodynamic diameter ranging from 2.1 to 4.7 µm. The dominant group of culturable bacteria within the studied period was Gram-positive rods-forming endospores (34–55%), while the least frequent were Gram-negative rods (2%). This research can be used to assess the health effects of exposure to bacterial aerosols in people living in this area. [ABSTRACT FROM AUTHOR]

Although evidence supports that the acne microbiome harbors a diverse range of microbes that play a vital role in the progression of acne vulgaris, the culturable microbes in the acne microbiome have not yet been largely identified. Here, we grew microbe colonies from entire acne lesions on agar plates and identified abundant Staphylococcus, Acinetobacter, and Pseudomonas species from forty selected single colonies. Staphylococcus species, including Staphylococcus epidermidis (S. epidermidis), Staphylococcus hominis (S. hominis), and Staphylococcus aureus (S. aureus), were isolated from tryptic soy broth (TSB) agar plates. However, Cutibacterium acnes (C. acnes) was predominately isolated from furazolidone-supplemented TSB agar plates. Results from gas chromatography-mass spectrometry (GC-MS) analysis revealed that, besides acetate, propionate and butyrate were the main short-chain fatty acids (SCFAs) in fermentation metabolites of C. acnes and S. epidermidis isolates, respectively. The culturable bacteria and SCFA profiles presented in this study provide a reservoir for selecting acne probiotics and developing SCFA-associated therapies against acne vulgaris. [Display omitted] • Culturable microbes including S. epidermidis were gained from entire acne lesions. • C. acnes was predominately isolated from furazolidone-supplemented agar plates. • Acetates and butyrate are main SCFAs in fermentation metabolites of S. epidermidis. • Propionate was abundantly produced by C. acnes isolates. • Our results provide a reservoir for selecting probiotics against acne vulgaris. [ABSTRACT FROM AUTHOR]

Another reason may be that the antibiotic types screened in vitro only inhibit the culturable bacteria in the I G. molesta i gut, while the inhibitory effect on the unculturable bacteria is unknown. In this study, after treatment with ciprofloxacin, there was no increase of the non-dominant bacteria to the dominant bacteria in the intestinal microbiota of I G. molesta i , but only changes in the relative abundance of the dominant bacteria. However, the minimum inhibitory concentration of ciprofloxacin against the intestinal bacteria of I C. capitata i was 5 g/mL, which was much higher than the 1 g/mL in this study, indicating that the intestinal bacteria of I G. molesta i were more sensitive to ciprofloxacin [[35]]. [Extracted from the article]

Red swamp crayfish (Procambarus clarkii) have become one of the favorite aquatic products in China. The modern farming mode which uses antibiotics to prevent diseases could impact the bacteria in crayfish intestines. Here, we determined the distribution and antimicrobial resistance phenotypes of the selected culturable bacteria in crayfish intestines and characterized an isolate with last-line antibiotic resistance determinant. Totally, 257 strains were isolated from 115 crayfish. These strains were highly diverse, with Citrobacter sp. (n = 94, 36.6%) and Aeromonas sp. (n = 88, 34.2%) being dominant. Other isolates belonged to genera Pseudomonas , Myroides , Morganella , Klebsiella , Acinetobacter , Proteus , Enterobacter , Kluyvera, and Escherichia. Most strains from crayfish were susceptible to all tested antibiotics. None of the isolates carried last-line antibiotic resistance genes except one Escherichia coli isolate with bla NDM-5 was detected, which is the first report of bla NDM-5-positive E. coli isolate from red swamp crayfish. Whole-genome sequencing suggested it belonged to ST48 and carried several resistance genes. bla NDM-5 was located within an Tn 3000 -like transposon linked to an external 5 bp sequence (ACTAT) on both sides on a IncHI1B/HI1A/FIA multi-replicon plasmid. This transposon was considered to be acquired by replicative transposition mediated by IS 3000. The emergence of bacteria with last-line antibiotic resistance genes in crayfish poses serious threat to public health since crayfish could act as a reservoir for the transfer of resistance to humans. [ABSTRACT FROM AUTHOR]

In recent years, monitoring of airborne bacteria and fungi concentrations has obtained increasing universal attraction not only for influences on ecological balance but also for evaluating their public health consequences. In this study, we aimed to investigate culturable airborne bacteria and fungi levels in different sites of Abadan, and their association with meteorological parameters and PM2.5 levels. Abadan is one of the most industrialized cities in the southwest of Iran where over the current decade has experienced lots of dust storm episodes. In total, 400 air samples were collected in 6 months (autumn and winter) using a single-stage viable Andersen cascade impactor for sampling airborne bacteria and fungi and portable DustTrak Aerosol Monitor 8520 for measuring PM2.5 concentrations and meteorological parameters. Microbial concentrations showed a significant difference between various sites over the study period with averages of 569.57 ± 312.64 and 482.73 ± 242.86 CFU/M3 for bacteria and fungi, respectively. The air temperature had a significant effect on the concentration of both airborne bacteria and fungi. A significant positive correlation between relative humidity and fungi but no correlation between relative humidity and bacteria concentrations were observed. The average airborne PM2.5 concentrations of all sites among the study period was 93.24 ± 116.72 μg/m3. The atmospheric bacterial and fungal communities were strongly positively correlated with the ambient PM2.5 level. The levels of airborne bacteria and fungi along with PM2.5 in the air of the city were relatively higher than the recommended levels. Therefore, the best course of action is needed to control emission sources. Further studies are also needed to evaluate the clinical analysis of the health effects of exposure to these pollutants. [ABSTRACT FROM AUTHOR]

In Portugal, the oak pinhole borer Platypus cylindrus and its mycobiota have been associated with cork oak (Quercus suber) death, but no knowledge exists regarding the associated bacterial community. However, it is known that some bacteria are important for ambrosia beetle symbiosis and play a role in oak tree health. To explore the bacteria associated with this beetle and its host, with the ultimate goal of highlighting potential roles in oak decline, this study used a culture‐dependent approach for strain isolation and phylogenetic identification using 16S rRNA gene sequencing and multilocus sequence analysis (MLSA). The bored galleries of different cork oak trees from a cork stand in Alentejo, together with the body and mycangia of adult beetles, were investigated. The samples revealed a diverse community comprising 500 isolates with 64 distinct types of bacterial colonies. Sixty‐eight strains were selected for sequencing and used for phylogenetic analysis, 40 from wood galleries and 28 from beetles. Thirty‐two genera of bacteria were identified, 18 of which were described for the first time within oak–beetle interactions. Major taxonomic groups were Actinobacteria in beetles and Enterobacterales in wood galleries. Although specific oak bacterial pathogens were not detected, a group of distinct strains detected in wood galleries, potentially belonging to a new Pectobacteriaceae species, were able to produce mild symptoms on cork oak plantlets. This study reports for the first time the biodiversity of culturable bacteria associated with the Q. suber–P. cylindrus interaction, their relevance to both organisms and the possible contribution to oak decline. [ABSTRACT FROM AUTHOR]

In this study, we developed an effective and stable technique for suppressing seedling rot of rice caused by Burkholderia glumae using bacterial communities cultured from nursery soils for organic farming (OF) of rice that have disease-suppressive activity. When culturable bacterial communities (CBCs) isolated from OF soils by growth on nutrient-agar (NA, nutrient-rich conditions) medium were added to autoclaved conventional nursery soil, a disease-suppressive effect on seedling rot was observed for some, but not all the CBCs obtained from soil samples. When bacteria were cultured under nutrient-poor conditions (1/1,000 diluted NA medium and 1/1,000 diluted nutrient-gellan gum medium), a disease-suppressive effect was observed more frequently. The disease-suppressive activity was maintained during repeated subculture on nutrient-poor media, but not on nutrient-rich media. These results suggest that CBCs have potential for disease control treatments, depending on their soil source and culture conditions. Analysis of the composition of CBCs suggested that bacteria in the order Burkholderiales may be responsible for the disease-suppressive activity. Correlated with the disease-suppressive effect, furthermore, the bacterial community structures that developed in rhizosphere soils after application of CBCs were stable and resistant to B. glumae invasion. Although culturable bacteria represent only a part of the bacterial populations of OF soils, it is possible that CBC application mimics the disease-suppressive effects of OF soils. [ABSTRACT FROM AUTHOR]

Red swamp crayfish (Procambarus clarkii) have become one of the favorite aquatic products in China. The modern farming mode which uses antibiotics to prevent diseases could impact the bacteria in crayfish intestines. Here, we determined the distribution and antimicrobial resistance phenotypes of the selected culturable bacteria in crayfish intestines and characterized an isolate with last-line antibiotic resistance determinant. Totally, 257 strains were isolated from 115 crayfish. These strains were highly diverse, with Citrobacter sp. (n = 94, 36.6%) and Aeromonas sp. (n = 88, 34.2%) being dominant. Other isolates belonged to genera Pseudomonas, Myroides, Morganella, Klebsiella, Acinetobacter, Proteus, Enterobacter, Kluyvera, and Escherichia. Most strains from crayfish were susceptible to all tested antibiotics. None of the isolates carried last-line antibiotic resistance genes except one Escherichia coli isolate with blaNDM-5 was detected, which is the first report of blaNDM-5-positive E. coli isolate from red swamp crayfish. Whole-genome sequencing suggested it belonged to ST48 and carried several resistance genes. blaNDM-5 was located within an Tn3000-like transposon linked to an external 5 bp sequence (ACTAT) on both sides on a IncHI1B/HI1A/FIA multi-replicon plasmid. This transposon was considered to be acquired by replicative transposition mediated by IS3000. The emergence of bacteria with last-line antibiotic resistance genes in crayfish poses serious threat to public health since crayfish could act as a reservoir for the transfer of resistance to humans.

Simple Summary: Radiation-resistant extremophiles have frequently been found in the Taklimakan Desert, which is known for its harsh conditions. However, there is no systemic study investigating the diversity and proportion of radiation-resistant strains among culturable bacteria. The results of this study revealed the distribution of culturable bacteria in the Taklimakan Desert and indicated high proportions of radiation-resistant strains in the culturable bacteria. The study helps to better understand the ecological origin of radio-resistance and to quantitatively describe the desert as a common habitat for radiation-resistant extremophiles. The Taklimakan Desert located in China is the second-largest shifting sand desert in the world and is known for its harsh conditions. Types of γ-rays or UV radiation-resistant bacterial strains have been isolated from this desert. However, there is no information regarding the proportions of the radiation-resistant strains in the total culturable microbes. We isolated 352 bacterial strains from nine sites across the Taklimakan Desert from north to south. They belong to Actinobacteria, Firmicutes, Proteobacteria, and Bacteroidetes. The phylum Actinobacteria was the most predominant in abundance and Firmicutes had the highest species richness. Bacteroidetes had the lowest abundance and was found in four sites only, while the other three phyla were found in every site but with different distribution profiles. After irradiating with 1000 J/m2 and 6000 J/m2 UV-C, the strains with survival rates higher than 10% occupied 72.3% and 36.9% of all culturable bacteria, respectively. The members from Proteobacteria had the highest proportions, with survival rates higher than 10%. After radiation with 10 kGy γ-rays, Kocuria sp. TKL1057 and Planococcus sp. TKL1152 showed higher radiation-resistant capabilities than Deinococcus radiodurans R1. Besides obtaining several radiation-resistant extremophiles, this study measured the proportions of the radiation-resistant strains in the total culturable microbes for the first time. This study may help to better understand the origin of radioresistance, especially by quantitatively comparing proportions of radiation-resistant extremophiles from different environments in the future. [ABSTRACT FROM AUTHOR]

Objective】 The objectives of this study were to investigate the diversity of the culturable bacterial population in the rhizosphere soil of tobacco plants suffering from tobacco bacterial wilt disease in Baoshan city, to reveal the relationship between the occurrence of tobacco bacterial wilt disease and the culturable microbial population, and to provide theoretical support for the prevention and control of tobacco bacterial wilt disease using microbial functional diversity. 【Method】 In this study, the rhizosphere soil samples of 30 diseased and 30 healthy tobacco plants from 30 villages belonging to 10 towns in Longyang district and Shidian county, Baoshan city, were collected. Culturable bacterial populations were obtained by the dilution plating method. Based on Illumina-Miseq high-throughput sequencing results, the differences in population composition and diversity of culturable bacteria in rhizosphere soil between healthy and diseased tobacco plants were analyzed. 【Result】 There were no significant differences in the number of OTUs and the α-diversity index of culturable bacteria in the rhizosphere soil between healthy and diseased tobacco plants. Compared with healthy tobacco plants, the relative abundance of Proteobacteria and Bacteroidetes in the rhizosphere of diseased tobacco plants was increased, while that of Firmicutes and Actinobacteria was decreased at the phylum level; At the class level, the relative abundance of Gamma proteobacteria and Bacteroidia was increased, and the relative abundance of Bacilli and Actinobacteria was decreased; At the genus level, the relative abundance of Pseudomonas, Achromobacter and Ensifer was increased, while the relative abundance of Pseudarthrobacter, Lysinibacillus, and Solibacillus were decreased. Sphingomonadales, Sphingomonadaceae, Phenylobacterium, Pseudonocardiales and Pseudonoca rdiaceae were the bacterial populations enriched in the rhizosphere soil of healthy tobacco plants, while Chitinophaga＿sp＿＿MHS12, Azospirillaceae, Azospirillum, and Flavitalea were the bacterial populations enriched in the rhizosphere soil of diseased tobacco plants. 【Conclusion】The culturable bacterial communities in the rhizosphere soil of healthy and diseased tobacco in Baoshan city showed a differentiated trend. The occurrence and development of tobacco bacterial wilt might be related to changes in the abundance of the tobacco plant rhizosphere bacterial population. The differentiated populations of culturable bacteria could be used for the biological control of tobacco bacterial wilt. [ABSTRACT FROM AUTHOR]

Mud banks and upwelling are two important oceanographic features occurring along the southwest coast of India during the southwest monsoon period. The study region, Alappuzha lying on the southwest coast of India, is unique due to the co-existence of upwelling and mud banks during the monsoon (MON) season. Water samples were collected from three stations, M1, M2, and M3, from April to September 2014, at weekly/biweekly intervals to determine the total bacterial abundance, viable prokaryotic counts, and total plate counts, along with measurements on physico-chemical parameters. For determining the heterotrophic culturable bacterial diversity, water samples were collected during two seasons, monsoon and pre-monsoon (PRM), from three stations. Water samples were inoculated into two non-selective broths for enrichment, DNA was extracted, and next-generation sequencing analysis was performed using Illumina Miseq sequencing. The sequence analysis revealed that dominant communities were Proteobacteria, followed by Firmicutes and Fusobacteria. Proportions of Fusobacteria increased during monsoon and proportions of Firmicutes were high in premonsoon season. Among Proteobacteria, Gammaproteobacteri is presented more than 99% of all the classes, irrespective of seasons. Vibrio was the most dominant genus during both seasons. The presence of anaerobic genera such as Propionigenium and Cetobacterium at all the stations during MON indicated the presence of upwelled waters. The genus Stenotrophomonas was observed in the M2 station alone. This study provides an overview of the culturable heterotrophic bacterial communities in a region in the southeastern Arabian Sea with coexisting mud banks and upwelling. The results of this study were compared with a published report on culture-independent bacterial diversity (from environmental DNA) from the same region. The study demonstrates that the use of culture media underrepresented the phylogenetic diversity and selectively enriched the class Gammaproteobacteria alone. [ABSTRACT FROM AUTHOR]

The Arabian Sea (AS) oxygen minimum zone (OMZ) is a site of intense denitrification, contributing to 20% of the global oceanic denitrification, playing a significant role in the nitrogen cycle. In this study, the structure and diversity of culturable bacterial communities inhabiting the water column of the AS OMZ were investigated through phylogenetic analysis and nitrate-utilizing ability was studied through culture-based studies. A total of 248 isolates collected during pre-monsoon and post-monsoon season were analysed for 16S rRNA gene sequences. Phylogenetic analysis revealed that the bacterial isolates belonged to 24 genera comprising class Gammaproteobacteria (79%), Firmicutes (18.15%), Bacteroidetes (1.61%) and Alphaproteobacteria (1.2%). Further, the ability of the organisms to reduce nitrate was tested by measuring nitrate reduction rate and nitrate reductase enzyme assay. Around 67% of the bacterial isolates were found to be nitrate reducers. The nitrate reduction rate ranged between 0.86–3.4 µM NO3− day−1 while nitrate reductase activity varied from 0.01–1.32 U ml−1. The presence of a high number of nitrate-reducing bacteria in this region signifies a link between functional diversity and ecosystem biogeochemistry of the OMZ region of the Arabian Sea. [ABSTRACT FROM AUTHOR]

The land-based oil extraction activity has led to serious pollution of the soil. While microbes may play an important role in the remediation of contaminated soils, ecological effects of oil pollution on soil microbial relationships remain poorly understood. Here, typical contaminated soils and undisturbed soils from seven oilfields of China were investigated in terms of their physicochemical characteristics, indigenous microbial assemblages, bacterial co-occurrence patterns, and metabolic enzymes. Network visualization based on k-core decomposition illustrated that oil pollution reduced correlations between co-existing bacteria. The core genera were altered to those related with oil metabolism (Pseudarthrobacter, Alcanivorax, Sphingomonas, Chromohalobacter and Nocardioides). Under oil pollution pressure, the indigenous bacteria Gammaproteobacteria was domesticated as biomarker and the enzyme expression associated with the metabolism of toxic benzene, toluene, ethylbenzene, xylene and polycyclic aromatic hydrocarbons was enhanced. Functional pathways of xenobiotics biodegradation were also stimulated under oil contamination. Finally, twelve culturable hydrocarbon-degrading microbes were isolated from these polluted soils and classified into Stenotrophomonas, Delftia, Pseudomonas and Bacillus. These results show that the soil microbial communities are transformed under oil pollution stress, and also provide useful information for future bioremediation processes.

Aedes (Ae.) albopictus is an important vector for many pathogens. Previous studies have revealed a role for midgut bacteria during pathogen infection in mosquitoes; however, studies of Ae. albopictus midgut bacteria are limited. We examined the diversity of midgut bacteria in female laboratory-colonized and field-collected Ae. albopictus. A total of 31 bacterial genera were identified representing 10 and 28 genera of laboratory-colonized and field-collected Ae. albopictus, respectively. The predominant bacterial genera in the laboratory-colonized Ae. albopictus were Staphylococcus and Micrococcus, whereas the bacterial diversity in the field-collected Ae. albopictus exhibited a higher proportion of Rhizobium and Agrobacterium as the dominant genera. However, only Staphylococcus showed a significant difference between laboratory-colonized and field-collected Ae. albopictus. The midgut bacterial species were identified from 30 laboratory-colonized Ae. albopictus mosquitoes. A total of 16 bacterial species were identified and the predominant bacterial species was Micrococcus luteus, followed by Staphylococcus epidermidis and Agrobacterium tumefaciens. Field mosquitoes were collected from the Sing Buri, Chumphon, and Yala Provinces of Thailand. The midgut bacterial species identified from the 10 Ae. albopictus collected from the Sing Buri Province included Bacillus subtilis, Staphylococcus haemolyticus, Staphylococcus hominis, and Serratia marcescens. Serratia marcescens was the only bacteria identified from this area. Midgut bacterial species were identified from 40 filed-collected Ae. albopictus from Chumphon Province. A total of 25 bacterial species were identified and the predominant species were Enterobacter cloacae, Micrococcus luteus, and Providencia rettgeri. Only 15 bacterial species were identified from the mosquitoes collected from Chumphon Province. A total of 18 bacterial species were identified from 30 Ae. albopictus collected from Yala Province and the predominant species were Rhizobium pusense and Agrobacterium tumefaciens. Only 12 bacterial species were found in mosquitoes collected from Yala Province. These findings indicate changes in the midgut bacteria population in Ae. albopictus from various locales, which may result from variability in the blood-meal source, diet, or habitat. A comprehensive survey of the midgut bacteria community prevalence in wild populations is critical for not only gaining a better understanding of the role of this bacterium in shaping the microbial community in Ae. albopictus, but also for informing current and future mosquito and disease control programs.

Molecular methods revealed that the majority of microbes in natural environments remains uncultivated. To fully understand the physiological and metabolic characteristics of microbes, however, culturing is still critical for microbial studies. Here, we used bacterial community analysis and four culture media, namely, traditional marine broth 2216 (MB), water extracted matter (WEM), methanol extracted matter (MEM), and starch casein agar (SCA), to investigate the diversity of cultivated bacteria in coastal sediments. A total of 1,036 isolates were obtained in pure culture, and they were classified into five groups, namely, Alphaproteobacteria (52.51%), Gammaproteobacteria (23.26%), Actinobacteria (13.32%), Firmicutes, and Bacteroidetes. Compared to other three media, WEM recovered a high diversity of actinobacteria (42 of 63 genotypes), with Micromonospora and Streptomyces as the most cultivated genera. Amplicon sequencing of the bacterial 16S ribosomal RNA (rRNA) gene V3–V4 fragment revealed eight dominant groups, Alphaproteobacteria (12.81%), Gammaproteobacteria (20.07%), Deltaproteobacteria (12.95%), Chloroflexi (13.09%), Bacteroidetes (8.28%), Actinobacteria (7.34%), Cyanobacteria (6.20%), and Acidobacteria (5.71%). The dominant members affiliated to Actinobacteria belonged to “Candidatus Actinomarinales,” “Candidatus Microtrichales,” and Nitriliruptorales. The cultivated actinobacteria accounted for a small proportion (

Molecular methods revealed that the majority of microbes in natural environments remains uncultivated. To fully understand the physiological and metabolic characteristics of microbes, however, culturing is still critical for microbial studies. Here, we used bacterial community analysis and four culture media, namely, traditional marine broth 2216 (MB), water extracted matter (WEM), methanol extracted matter (MEM), and starch casein agar (SCA), to investigate the diversity of cultivated bacteria in coastal sediments. A total of 1,036 isolates were obtained in pure culture, and they were classified into five groups, namely, Alphaproteobacteria (52.51%), Gammaproteobacteria (23.26%), Actinobacteria (13.32%), Firmicutes, and Bacteroidetes. Compared to other three media, WEM recovered a high diversity of actinobacteria (42 of 63 genotypes), with Micromonospora and Streptomyces as the most cultivated genera. Amplicon sequencing of the bacterial 16S ribosomal RNA (rRNA) gene V3–V4 fragment revealed eight dominant groups, Alphaproteobacteria (12.81%), Gammaproteobacteria (20.07%), Deltaproteobacteria (12.95%), Chloroflexi (13.09%), Bacteroidetes (8.28%), Actinobacteria (7.34%), Cyanobacteria (6.20%), and Acidobacteria (5.71%). The dominant members affiliated to Actinobacteria belonged to " Candidatus Actinomarinales," " Candidatus Microtrichales," and Nitriliruptorales. The cultivated actinobacteria accounted for a small proportion (<5%) compared to the actinobacterial community, which supported that the majority of actinobacteria are still waiting for cultivation. Our study concluded that WEM could be a useful and simple culture medium that enhanced the recovery of culturable actinobacteria from coastal sediments. [ABSTRACT FROM AUTHOR]

Bioaerosol concentrations in residential buildings located in the Northeastern US have not been widely studied. Here, in 2011‐2015, we studied the presence and seasonal variability of culturable fungi and bacteria in three multi‐family apartment buildings and correlated the bioaerosol concentrations with building ventilation system types and environmental parameters. A total of 409 indoor and 86 outdoor samples were taken. Eighty‐five percent of investigated apartments had indoor‐outdoor (I/O) ratios of culturable fungi below 1, suggesting minimal indoor sources of fungi. In contrast, 56% of the apartments had I/O ratios for culturable bacteria above 1, indicating the prominence of indoor sources of bacteria. Culturable fungi I/O ratios in apartments serviced by central heating, ventilation, and air‐conditioning (HVAC) system were lower than those in apartments with window AC. The type of ventilation system did not have a significant effect on the presence of indoor culturable bacteria. A significant positive association was determined between indoor dew point (DP) levels and indoor culturable fungi (P <.001) and bacteria (P <.001), regardless of ventilation type. Also, residents in apartments with central HVAC did not experience extreme DP values. We conclude that building ventilation systems, seasonality, and indoor sources are major factors affecting indoor bioaerosol levels in residential buildings. [ABSTRACT FROM AUTHOR]

The rhizospheric bacterial community associated with desert shrub is an important part of sandy land ecosystems. In this study, we isolated and characterized culturable bacteria associated with Caragana microphylla from a wide range of habitats in North China. We chose five habitats with different aridity index values and dune types. In both trials, soil physicochemical parameters and culturable bacterial populations showed the rhizosphere effects. The culturable bacterial communities of rhizosphere and bulk soil were determined using 16s rDNA sequencing. We identified that the proportions of beneficial bacterial strains with plant growth promoting (PGP) traits (nitrogen fixation, phosphate solubilization and indole acetic acid production) were significantly greater in rhizosphere soil than in bulk soil. Some of the strains screened in this study had significant effects on the growth of Arabidopsis seedlings. These effects included inhibiting the elongation of primary roots, promoting lateral root formation and increasing the shoot fresh weight. In conclusion, our study provides a comprehensive survey of the culturable bacterial populations of the rhizosphere in C. microphylla habitats and identifies potential PGPBs that may help develop an efficient revegetation strategy to manage desert land.

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Urinary incontinence (UI) is a burdensome condition with high prevalence in middle-aged to older women and an unclear etiology. Advances in our understanding of host-microbe interactions in the urogenital tract have stimulated interest in the urinary microbiome. DNA sequencing and enhanced urine culture suggest that similarly to other mucosal sites, the urinary bladder of healthy individuals harbors resident microbial communities that may play distinct roles in bladder function. This review focused on the urobiome (expanded quantitative urine culture-based or genomic sequencing-based urinary microbiome) associated with different subtypes of UI, including stress, urgency and mixed urinary incontinence, and related syndromes, such as interstitial cystitis and overactive bladder in women, contrasted to urinary tract infections. Furthermore, we examined clinical evidence for the association of the urinary microbiome with responses to pharmacotherapy for amelioration of UI symptoms. Although published studies are still relatively limited in number, study design and sample size, cumulative evidence suggests that certain Lactobacillus species may play a role in maintaining a healthy bladder milieu. Higher bacterial diversity in the absence of Lactobacillus dominance was associated with urgency UI and resistance to anticholinergic treatment for this condition. UI may also facilitate the persistence of uropathogens following antibiotic treatment, which in turn can alter the commensal/potentially beneficial microbial communities. Risk factors of UI, including age, menopausal status, sex steroid hormones, and body mass index may also impact the urinary microbiome. However, it is yet unclear whether the effects of these risks factors on UI are mediated by urinary host-microbe interactions and a mechanistic link with the female urogenital microbiome is still to be established. Strategies for future research are suggested.

Antibiotic resistance genes are considered to be emerging contaminants. Considering the limited number of papers on detection of antibiotic resistance genes in metal-polluted soils of Iran and due to the fact that nonclinical strains carrying resistance determinants can be the origin of resistance genes in clinical isolates, the present study was conducted to detect some resistance genes (i.e., blaTEM, vanA, tetB, strA, and aac(3)-II) in the most prevalent culturable bacteria isolated from soils around mines. A total of 70 species of Pseudomonas, Azotobacter, Enterobacter, and Bacillus were isolated from soils under different land uses. Polymerase chain reaction was used to detect resistance genes in the isolates. The blaTEM gene was the most abundant gene detected in the isolates (45.71%). The number of Azotobacter, Pseudomonas, and Enterobacter isolates containing blaTEM was higher in the agricultural and pasture soils than in the mining waste soils (28.57%, 57.14%, and 20%, respectively), but the pasture and mining waste soils proved to harbor more Bacillus species containing blaTEM compared to the agricultural soils (64.28%, 50%, and 42.86%, respectively). The vanA gene was found in 5.71% of all the strains, and only one Pseudomonas isolates harbored aac(3)-II. The tetB and strA genes were not detected in any of the isolates. More than 77% of the isolates were phenotypically resistant to β-lactams, and 28.57%, 40%, and 31.43% of them were resistant to streptomycin, vancomycin, and tetracyclines, respectively. Overall, the high number of bacteria containing at least one resistance gene isolated from the samples indicated the persistence of environmental reservoirs of resistance genes in the metal-polluted soils. [ABSTRACT FROM AUTHOR]

The rhizospheric bacterial community associated with desert shrub is an important part of sandy land ecosystems. In this study, we isolated and characterized culturable bacteria associated with Caragana microphylla from a wide range of habitats in North China. We chose five habitats with different aridity index values and dune types. In both trials, soil physicochemical parameters and culturable bacterial populations showed the rhizosphere effects. The culturable bacterial communities of rhizosphere and bulk soil were determined using 16s rDNA sequencing. We identified that the proportions of beneficial bacterial strains with plant growth promoting (PGP) traits (nitrogen fixation, phosphate solubilization and indole acetic acid production) were significantly greater in rhizosphere soil than in bulk soil. Some of the strains screened in this study had significant effects on the growth of Arabidopsis seedlings. These effects included inhibiting the elongation of primary roots, promoting lateral root formation and increasing the shoot fresh weight. In conclusion, our study provides a comprehensive survey of the culturable bacterial populations of the rhizosphere in C. microphylla habitats and identifies potential PGPBs that may help develop an efficient revegetation strategy to manage desert land. [ABSTRACT FROM AUTHOR]