scholarly journals Distinctly different bacterial communities in surface and oxygen minimum layers in the Arabian Sea

2016 ◽  
Author(s):  
Mandar Bandekar ◽  
Nagappa Ramaiah ◽  
Anand Jain ◽  
Ram Murti Meena
Keyword(s):  
Bacterial Community ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Arabian Sea ◽  
16S Rrna Gene Sequencing ◽  
Molecular Techniques ◽  
Rrna Gene ◽  
Northeast Monsoon ◽  
Rrna Gene Sequencing ◽  
Oxygen Minimum

Abstract. Contributions of microbial communities to biogeochemical processes in oxygen minimum oceanic zones are being realized through the applications of molecular techniques. To understand seasonal and depth-wise variations in bacterial community structure (BCS) in the Arabian Sea oxygen minimum region, extensive sampling and molecular analyses were carried out. 16S rRNA gene sequencing was done to profile the BCS from five depths, surface (5 m), deep chorophyll maximum (43–50 m, DCM), 250 m, 500 m and 1000 m during Spring intermonsoon (SIM), Fall intermonsoon (FIM), and Northeast monsoon (NEM) seasons. Sequencing of 743 chimera-free clones revealed a clear vertical partitioning of BCS between the surface (surface + DCM) and OMZ (250 + 500 + 1000 m) layers. There was no distinct seasonal difference in the BCS. Most 16S rRNA gene sequences were affiliated to Gammaproteobacteria (39.31 %), Alphaproteobacteria (23.56 %) and Cyanobacteria (20.2 %). Higher diversity and OTUs in OMZ predominantly consisting of Alteromonodales, Sphinogomonadales, Rhodobacterales, Burkholderales, and Acidimicrobiales we observed might be due to their microaerophilic metabolism, ability to degrade recalcitrant substrates and assimilate sinking particulate matter. Further hitherto undescribed diversity both in surface and OMZ layers was evidenced. Implicit role of extant bacterial community in denitrification and anammox and in sulphur oxidation is highlighted.

Characterization of bacterial community structure dynamics in a rat burn wound model using 16S rRNA gene sequencing

2022 ◽  
Author(s):  
Chen Zheng-li ◽  
Peng Yu ◽  
Wu Guo-sheng ◽  
Hong Xu-Dong ◽  
Fan Hao ◽  
...  
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Bacterial Community Structure ◽  
Bacterial Species ◽  
16S Rrna Gene Sequencing ◽  
Rrna Gene ◽  
Sprague Dawley ◽  
Rrna Gene Sequencing

Abstract Burns destroy the skin barrier and alter the resident bacterial community, thereby facilitating bacterial infection. To treat a wound infection, it is necessary to understand the changes in the wound bacterial community structure. However, traditional bacterial cultures allow the identification of only readily growing or purposely cultured bacterial species and lack the capacity to detect changes in the bacterial community. In this study, 16S rRNA gene sequencing was used to detect alterations in the bacterial community structure in deep partial-thickness burn wounds on the back of Sprague-Dawley rats. These results were then compared with those obtained from the bacterial culture. Bacterial samples were collected prior to wounding and 1, 7, 14, and 21 days after wounding. The 16S rRNA gene sequence analysis showed that the number of resident bacterial species decreased after the burn. Both resident bacterial richness and diversity, which were significantly reduced after the burn, recovered following wound healing. The dominant resident strains also changed, but the inhibition of bacterial community structure was in a non-volatile equilibrium state, even in the early stage after healing. Furthermore, the correlation between wound and environmental bacteria increased with the occurrence of burns. Hence, the 16S rRNA gene sequence analysis reflected the bacterial condition of the wounds better than the bacterial culture. 16S rRNA sequencing in the Sprague-Dawley rat burn model can provide more information for the prevention and treatment of burn infections in clinical settings and promote further development in this field.

Screening and Molecular Characterization of Cellulase Producing Actinobacteria from Litchi Orchard

2019 ◽  
Vol 13 (1) ◽  
pp. 90-101
Author(s):  
Sanju Kumari ◽  
Utkarshini Sharma ◽  
Rohit Krishna ◽  
Kanak Sinha ◽  
Santosh Kumar
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Molecular Characterization ◽  
Biochemical Characterization ◽  
Evolutionary Relationship ◽  
Gene Sequencing ◽  
Cellulase Activity ◽  
16S Rrna Gene Sequencing ◽  
Rrna Gene ◽  
Rrna Gene Sequencing

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.

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