Identification Of Bacterial Populations Research Articles

Identification of Bacterial Population from Diabetic Wound of Mice to Study the Bactericidal Efficacy of Green Synthesized Silver Nanoparticle by Saraca asoca Bark Extract

Identification of Bacterial Population from Diabetic Wound of Mice to Study the Bactericidal Efficacy of Green Synthesized Silver Nanoparticle by Saraca asoca Bark Extract

Identification of Bacterial Populations and Functional Mechanisms Potentially Involved in Biochar-Facilitated Antagonism of the Soilborne PathogenFusarium oxysporum

Biochar soil amendment alleviates plant disease through microbial-mediated processes but drivers facilitating this “biochar effect” are not fully understood. In this study, cucumber plants were inoculated with and without the fungus Fusarium oxysporum f. sp. radicis-cucumerinum in either biochar-amended or nonamended soils, and disease severity was assessed. Amplicon sequencing and shotgun metagenomics were then applied to identify bacteria and associated mechanisms potentially involved in pathogen inhibition, and candidate bacteria were tested for in vitro F. oxysporum f. sp. radicis-cucumerinum-antagonizing capacity. Biochar-amended plants showed lower F. oxysporum f. sp. radicis-cucumerinum-associated growth stagnation compared with nonamended plants, supporting the biochar effect. Their rhizosphere had a more diverse microbiome with higher levels of secondary metabolite-encoding biosynthetic gene clusters (BGCs). Families Pseudonocardiaceae (Lentzea spp.) and Myxococcaceae were significantly more abundant in biochar-amended rhizospheres of F. oxysporum f. sp. radicis-cucumerinum-inoculated plants, and metagenomically assembled genomes (MAGs) from these taxa contained genes encoding enzymes involved in binding and degradation of chitin, and novel BGCs encoding secondary metabolites. Lentzea spp. isolates related to the above MAGs showed in vitro antagonistic activity against F. oxysporum f. sp. radicis-cucumerinum. Collectively, we postulate that biochar amendment generates a “buffering effect” that reduces F. oxysporum f. sp. radicis-cucumerinum-facilitated destabilization of the root-associated microbiome, maintaining beneficial taxa that produce antagonizing enzymes and secondary metabolites that sustain plant health.

ASSESSMENT OF BACTERIA IN AQUAPONICS BY CULTURE DEPENDENT TECHNIQUES

Aquaponics is an intensive sustainable food production system that combines aquaculture and hydroponics, in which fish and plants grow together symbiotically. In an aquaponic unit, the effluent rich nutrients derived from nitrogenous waste excreted from fish, fish feed and decomposing organic matter,fertilizes hydroponic beds providing essential nutrients for plant growth. Simplified raft aquaponic system vary greatly in design and construction, but perform all key functions of plant and fish production, removal of suspended solids and bacterial nitrification. All life forms require nitrogen as an integral part of proteins and nucleic acids, therefore all living organisms are involved in the nitrogen cycle. This process is primarily accomplished by two groups of autotrophic nitrifying bacteria that can build organic molecules and utilize CO2 as the carbon source for biosynthesis and oxidation of nitrogen compounds as the energy source. Abroad range of major parameters and factors affecting bacterial growth has been studied in this paper which are essential for nitrification, that include healthy biofilter with appropriate water conditions like, water temperature, pH, dissolved oxygen (DO), total nitrogen concentrations. Characterization and identification of bacterial populations in an aquaponics system has been carried out by cultivation-dependant techniques and traditional methods of analyzing microbial communities using standard light microscopy.

Isolation, Characterization, and Identification of Bacterial Population from Textile and Tannery Effluents of Bangladesh

Ten effluent samples from two different sites located at Hazaribagh tannery belt and Dhaka EPZ, Savar were collected. This study aimed to compare the bacterial composition isolated from tannery and textile effluents and to investigate the occurrence of metal toxicity tolerant and dye degrading bacteria and to select the potential strains for the use in bioremediation. The average bacterial count of HT and DETDE varied in between 3.35×106 and 5.45×106 cfu/mL and 4.8×106 and 7.75×106cfu/mL, respectively. A total of 12 bacterial isolates were characterized as strains of Bacillus, Staphylococcus, and Pseudomonas. A few, however, were re-cultured on other recommended media for verification of diagnostic characteristics. Maximum numbers of bacterial species were isolated from textile effluent. The results showed that a Gram-positive bacillus with a yellow pigment was considered as a major group of the population. Among them three isolates were identified based on alignments of partial sequence of 16S rRNA gene. These are also being used in different wastewater and metal treatment plants all over the world.Bangladesh J Microbiol, Volume 29, Number 2, Dec 2012, pp 84-88

Identification of bacterial populations in drinking water using 16S rRNA-based sequence analyses

Intracellular RNA is rapidly degraded in stressed cells and is more unstable outside of the cell than DNA. As a result, RNA-based methods have been suggested to study the active microbial fraction in environmental matrices. The aim of this study was to identify bacterial populations in drinking water by analyzing 16S rRNA-based clone libraries. Hollow-fiber ultrafiltration was used to concentrate bacterial communities from 40 l of tap water collected at 12 different times during three different summer months from a single point-of-use. Total RNA was extracted from the microbial concentrates and used to develop 16S rRNA-based clone libraries. Phylogenetic analyses of 1231 partial 16S rRNA gene sequences showed that difficult-to-classify bacterial sequences were the most predominant clones, representing 57.6% of the sequences analyzed. Within these unclassified clades, most sequences were closely related to sequences retrieved from previous DNA- and RNA-based drinking water studies. Other bacterial groups represented in this study included Proteobacteria, cyanobacteria, Actinobacteria, Bacteroidetes, and Planctomycetes. Overall, the results suggest that these bacterial groups are amongst potentially active bacteria in drinking water. Diversity analyses of clones generated show that while overall diversity is similar amongst the different months, membership changes with respect to time. The results from this study further improve our understanding of the molecular diversity and bacterial population dynamics of drinking water microbial communities. Moreover, these results provide the sequence foundation for the development of molecular assays that target active drinking water bacteria.

Identification of bacterial populations in dairy wastewaters by use of 16S rRNA gene sequences and other genetic markers.

Hydraulic flush waste removal systems coupled to solid/liquid separators and circulated treatment lagoons are commonly utilized to manage the large amounts of animal waste produced on high-intensity dairy farms. Although these systems are common, little is known about the microbial populations that inhabit them or how they change as they traverse the system. Using culture-based and non-culture-based methods, we characterized the microbial community structure of manure, water from the separator pit, and water from the circulated treatment lagoon from a large dairy in the San Joaquin Valley of California. Our results show that both total bacterial numbers and bacterial diversity are highest in manure, followed by the separator pit water and the lagoon water. The most prevalent phylum in all locations was the Firmicutes (low-G+C, gram-positive bacteria). The most commonly occurring operational taxonomic unit (OTU) had a 16S rRNA gene (rDNA) sequence 96 to 99% similar to that of Clostridium lituseburense and represented approximately 6% of the manure derived sequences, 14% of the separator pit-derived sequences and 20% of the lagoon-derived sequences. Also highly prevalent was an OTU with a 16S rDNA sequence 97 to 100% similar to that of Eubacterium tenue, comprising approximately 3% of the manure-derived sequences, 6% of the separator pit-derived sequences and 9% of the lagoon-derived sequences. Taken together, these sequences represent approximately one-third of the total organisms in the lagoon waters, suggesting that they are well adapted to this environment.

Characterization of bacteria by multiparameter flow cytometry

An arc-lamp based flow cytometer was used to obtain high resolution measurements of the light scattering characteristics and DNA contents of eight different bacteria. Light scatter profiles of bacteria are a useful first step when flow cytometry is used to characterize organisms. Scanning and transmission electron microscopy of the bacterial samples demonstrate that the structural basis of the light scattering profiles is not always clear, i.e. some organisms appear to have anomalous light scattering characteristics. The use of a third measurement parameter, DNA content, allowed much better discrimination of the organisms. Flow cytometry shows great promise as a method for the rapid discrimination and identification of bacterial populations.

Enumeration and characterization of standard plate count bacteria in chlorinated and raw water supplies

Nearly 700 standard plate count (SPC) bacteria were isolated from drinking water and untreated surface water and identified according to a scheme developed to permit the rapid, simple classification of microorganisms to genus, species, or group. Actinomycetes and Aeromonas species were the two most common groups of SPC bacteria in chlorinated distribution water. Aeromonas spp. and Enterobacter agglomerans were the two most common groups of SPC bacteria in raw water. Identification of bacterial populations before and after contact with chlorine (1 to 2 mg/liter) for 1 h revealed that chlorination selected for gram-positive bacteria. Water that contained high densities of bacteria known to be antagonistic to coliforms had low coliform isolation rates. The membrane filtration technique for enumerating SPC bacteria recovered significantly higher numbers (P < 0.001) than the standard pour plate technique.