Chitinolytic bacteria in the intestinal tract of Japanese coastal fishes

2006 ◽  
Vol 52 (12) ◽  
pp. 1158-1163 ◽  
Author(s):  
Shiro Itoi ◽  
Toshihiro Okamura ◽  
Yuki Koyama ◽  
Haruo Sugita

Intestinal bacteria from several coastal fish species were screened on 1/20 PYBG medium containing 0.2% colloidal chitin, and 361 bacteria capable of decomposing colloidal chitin were isolated. These isolates were subsequently screened on media containing either 0.5% α-chitin or 0.5% β-chitin resulting in the identification of 31 α-chitinolytic and 275 β-chitinolytic bacterial isolates. Partial 16S rRNA gene sequencing was carried out and homology searches of the resultant sequences against the DDBJ, EMBL, and GenBank databases revealed that the majority (99%) of the chitinolytic bacteria isolated belonged to the Vibrionaceae. Phylogenetic analysis using a Bayesian approach showed that the α-chitinolytic bacteria belonging to the Vibrionaceae formed a separate cluster from the non-α-chitinolytic bacteria in the Vibrionaceae.Key words: chitinolytic bacteria, 16S rRNA, α-chitin, coastal fish, intestinal bacteria.

2021 ◽  
Author(s):  
Mudgil Devender ◽  
Dhiraj Paul ◽  
Sushmitha Baskar ◽  
Ramanathan Baskar ◽  
Yogesh S Shouche

Abstract This study reports on the culturable microbial communities in caves from the Indian sub-continent. A high bacterial diversity and a greater bacterial taxonomic diversity is reported using MALDI-TOF spectrometry and 16S rRNA gene sequencing. This approach helped to detect a number bacterial strains from the Indian caves. The microbial diversity in the Indian caves is inadequately characterized. The study aims to expand the current understanding of bacterial diversity in the speleothems from Krem Soitan, Krem Lawbah, Krem Mawpun in Khasi Hills, Meghalaya, India. High microbial enumerations were observed on dilute nutrient agar (5.3 × 103 to 8.8 × 105) followed by M9 minimal medium (4 × 104 to 1.7 × 105) and R2A medium (1.0 × 104 to 5.7 × 105). A total of 826 bacterial isolates were selected and preserved for the study. 295 bacterial isolates were identified using MALDI-TOF spectrometry and the isolates which showed no reliable peaks were further identified by 16S rRNA gene sequencing. 91% of the total bacterial diversity was dominated by Proteobacteria and Actinobacteria. The other important phyla detected include the Firmicutes (7.45%), Deinococcus-Thermus (0.33%) and Bacteroidetes (0.67%). At the genus level, Pseudomonas (55%) and Arthrobacter (23%) were ubiquitous followed by Acinetobacter, Bacillus, Brevundimonas, Deinococcus, Flavobacterium, Paenibacillus, Pseudarthrobacter. Multivariate statistical analysis indicated that the bacterial genera formed separate clusters depending on the geochemical constituents in the spring waters suitable for their growth and metabolism. A culture-dependent approach was employed for elucidating the community structure colonizing the speleothems and wall deposits in the caves using MALDI-TOF and 16S rRNA gene sequencing. To the best of our knowledge, there are no previous geomicrobiological investigations in these caves and this study is a pioneering culture dependent study of the microbial community with many cultured isolates.


2020 ◽  
Vol 15 (3) ◽  
Author(s):  
Pragya Lakshmi ◽  
Alok Bharadwaj ◽  
Ranjan Kumar Srivastava

Objectives: The purpose of this study was to identify bacteria in urine samples of pregnant women of asymptomatic and symptomatic women by 16S rRNA gene sequencing. This study aims to identify different strains of microbes causing urinary tract infection (UTI). Methods: In the semi-quantitative culture technique, bacterial isolates such as Escherichia coli, Klebsiella, Pseudomonas, Staphylococcus, Coagulase-negative Staphylococcus, and Proteus were subjected to 16S rRNA gene sequencing followed by BLAST analysis and phylogenetic tree formation. The 16S rRNA gene sequencing was carried out to identify the specific strains of bacteria causing UTI. Results: According to the BLAST analysis, sample 1 revealed a 100% similarity to E. coli strain U5/41. Likewise, samples 2, 3, 4, 5 and 6 exhibited a 100% similarity to Klebsiella aerogenes strain F26, Pseudomonas entomophila strain 2014, Staphylococcus aureus strain NCTC13616, Staphylococcus saprophyticus strain FDAARGOS_355, Proteus mirabilis strain NCTC 11938, respectively. Conclusions: Six bacterial isolates were analyzed by 16S RNA gene sequencing followed by the construction of a phylogenetic tree construction up to the species level. This method was a valuable tool for cost-effective and accurate diagnosis of an array of uropathogens in both asymptomatic and symptomatic pregnant women.


2020 ◽  
Author(s):  
Alicyn Reverdy ◽  
Daniel Hathaway ◽  
Jessica Jha ◽  
Gabriel Michaels ◽  
Jeffrey Sullivan ◽  
...  

AbstractThe Atacama Desert, the driest and oldest desert in the world, is a hostile environment for life. Despite the inhospitable conditions, bacterial sequences detected in this location suggest rich bacterial life. This study tested the idea that certain bacteria would thrive in this location and that some of them could be cultivated permitting further characterization. Environmental surface soil samples from 1-5 cm deep were collected from 18 diverse locations within the Atacama Desert. To assess the bacterial taxa, diversity, and abundance, Illumina 16S rRNA gene sequencing was performed directly on soil samples. Bacteria were also cultured from the samples. We have a collection of 74 unique bacterial isolates after cultivation and confirmation by 16S rRNA gene sequencing. Pigmentation, biofilm formation, antibiotic production against Escherichia coli MG1655 and Staphylococcus aureus HG003, and antibiotic resistance were assessed on these isolates. We found that approximately a third of the colonies produced pigments, 80% of isolates formed biofilms, many isolates had antibiotic activity against E. coli and/or S. aureus, and many were resistant to commercial antibiotics. The functional characterization of these isolates gives us insight into the adaptive bacterial strategies in harsh environments and enables us to learn about their possible use in agriculture, healthcare, or biotechnology.Originality-Significant StatementThis study provides the first microbial diversity analysis from Atacama Desert soil, presents the cultivation and isolation of 74 unique bacterial isolates, many of which may be novel genera and species, and explores pigment production, antibiotic production and resistance, and unique biofilm development as bacterial survival strategies for living within extreme environments.


2019 ◽  
Vol 13 (1) ◽  
pp. 90-101
Author(s):  
Sanju Kumari ◽  
Utkarshini Sharma ◽  
Rohit Krishna ◽  
Kanak Sinha ◽  
Santosh Kumar

Background: Cellulolysis is of considerable economic importance in laundry detergents, textile and pulp and paper industries and in fermentation of biomass into biofuels. Objective: The aim was to screen cellulase producing actinobacteria from the fruit orchard because of its requirement in several chemical reactions. Methods: Strains of actinobacteria were isolated on Sabouraud’s agar medium. Similarities in cultural and biochemical characterization by growing the strains on ISP medium and dissimilarities among them perpetuated to recognise nine groups of actinobacteria. Cellulase activity was measured by the diameter of clear zone around colonies on CMC agar and the amount of reducing sugar liberated from carboxymethyl cellulose in the supernatant of the CMC broth. Further, 16S rRNA gene sequencing and molecular characterization were placed before NCBI for obtaining recognition with accession numbers. Results: Prominent clear zones on spraying Congo Red were found around the cultures of strains of three groups SK703, SK706, SK708 on CMC agar plates. The enzyme assay for carboxymethylcellulase displayed extra cellulase activity in broth: 0.14, 0.82 and 0.66 µmol mL-1 min-1, respectively at optimum conditions of 35°C, pH 7.3 and 96 h of incubation. However, the specific cellulase activities per 1 mg of protein did not differ that way. It was 1.55, 1.71 and 1.83 μmol mL-1 min-1. The growing mycelia possessed short compact chains of 10-20 conidia on aerial branches. These morphological and biochemical characteristics, followed by their verification by Bergey’s Manual, categorically allowed the strains to be placed under actinobacteria. Further, 16S rRNA gene sequencing, molecular characterization and their evolutionary relationship through phylogenetics also confirmed the putative cellulase producing isolates of SK706 and SK708 subgroups to be the strains of Streptomyces. These strains on getting NCBI recognition were christened as Streptomyces glaucescens strain SK91L (KF527284) and Streptomyces rochei strain SK78L (KF515951), respectively. Conclusion: Conclusive evidence on the basis of different parameters established the presence of cellulase producing actinobacteria in the litchi orchard which can convert cellulose into fermentable sugar.


Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Janis R. Bedarf ◽  
Naiara Beraza ◽  
Hassan Khazneh ◽  
Ezgi Özkurt ◽  
David Baker ◽  
...  

Abstract Background Recent studies suggested the existence of (poly-)microbial infections in human brains. These have been described either as putative pathogens linked to the neuro-inflammatory changes seen in Parkinson’s disease (PD) and Alzheimer’s disease (AD) or as a “brain microbiome” in the context of healthy patients’ brain samples. Methods Using 16S rRNA gene sequencing, we tested the hypothesis that there is a bacterial brain microbiome. We evaluated brain samples from healthy human subjects and individuals suffering from PD (olfactory bulb and pre-frontal cortex), as well as murine brains. In line with state-of-the-art recommendations, we included several negative and positive controls in our analysis and estimated total bacterial biomass by 16S rRNA gene qPCR. Results Amplicon sequencing did detect bacterial signals in both human and murine samples, but estimated bacterial biomass was extremely low in all samples. Stringent reanalyses implied bacterial signals being explained by a combination of exogenous DNA contamination (54.8%) and false positive amplification of host DNA (34.2%, off-target amplicons). Several seemingly brain-enriched microbes in our dataset turned out to be false-positive signals upon closer examination. We identified off-target amplification as a major confounding factor in low-bacterial/high-host-DNA scenarios. These amplified human or mouse DNA sequences were clustered and falsely assigned to bacterial taxa in the majority of tested amplicon sequencing pipelines. Off-target amplicons seemed to be related to the tissue’s sterility and could also be found in independent brain 16S rRNA gene sequences. Conclusions Taxonomic signals obtained from (extremely) low biomass samples by 16S rRNA gene sequencing must be scrutinized closely to exclude the possibility of off-target amplifications, amplicons that can only appear enriched in biological samples, but are sometimes assigned to bacterial taxa. Sequences must be explicitly matched against any possible background genomes present in large quantities (i.e., the host genome). Using close scrutiny in our approach, we find no evidence supporting the hypothetical presence of either a brain microbiome or a bacterial infection in PD brains.


2021 ◽  
Vol 45 (1) ◽  
Author(s):  
Musa Saheed Ibrahim ◽  
Beckley Ikhajiagbe

Abstract Background Rice forms a significant portion of food consumed in most household worldwide. Rice production has been hampered by soil factors such as ferruginousity which has limited phosphorus availability; an important mineral component for the growth and yield of rice. The presence of phosphate-solubilizing bacteria (PSB) in soils has been reported to enhance phosphate availability. In view of this, the present study employed three bacteria species (BCAC2, EMBF2 and BCAF1) that were previously isolated and proved P solubilization capacities as inocula to investigate the growth response of rice germinants in an in vitro setup. The bacteria isolates were first identified using 16S rRNA gene sequencing and then applied as inoculum. The inolula were prepared in three concentrations (10, 7.5 and 5.0 ml) following McFarland standard. Viable rice (var. FARO 44) seeds were sown in petri dishes and then inoculated with the three inocula at the different concentrations. The setup was studied for 28 days. Results 16S rRNA gene sequencing identified the isolates as: isolate BCAC2= Bacillus cereus strain GGBSU-1, isolate BCAF1= Proteus mirabilis strain TL14-1 and isolate EMBF2= Klebsiella variicola strain AUH-KAM-9. Significant improvement in rice germination, morphology, physiology and biomass parameters in the bacteria-inoculated setups was observed compared to the control. Germination percentage after 4 days was 100 % in the inoculated rice germinants compared to 65% in the control (NiS). Similarly, inoculation with the test isolates enhanced water-use efficiency by over 40%. The rice seedlings inoculated with Bacillus cereus strain GGBSU-1 (BiS) showed no signs of chlorosis and necrosis throughout the study period as against those inoculated with Proteus mirabilis strain TL14-1 (PiS) and Klebsiella variicola strain AUH-KAM-9 (KiS). Significant increase in chlorophyll-a, chlorophyll-b and alpha amylase was observed in the rice seedlings inoculated with BiS as against the NiS. Conclusion Inoculating rice seeds with Bacillus cereus strain GGBSU-1, Proteus mirabilis strain TL14-1 and Klebsiella variicola strain AUH-KAM-9 in an in vitro media significantly improved growth parameters of the test plant. Bacillus cereus strain GGBSU-1 showed higher efficiency due to a more improved growth properties observed.


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