scholarly journals Morphological and Phylogenetic Characterizations of Freshwater Thioploca Species from Lake Biwa, Japan, and Lake Constance, Germany

2003 ◽  
Vol 69 (1) ◽  
pp. 390-398 ◽  
Author(s):  
Hisaya Kojima ◽  
Andreas Teske ◽  
Manabu Fukui
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Lake Biwa ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Uranyl Acetate ◽  
Lake Constance ◽  
Rrna Gene ◽  
Rrna Sequence ◽  
16S Rrna Sequence ◽  
Gradient Gel Electrophoresis

ABSTRACT Filamentous, gliding, sulfide-oxidizing bacteria of the genus Thioploca were found on sediments in profundal areas of Lake Biwa, a Japanese freshwater mesotrophic lake, and were characterized morphologically and phylogenetically. The Lake Biwa Thioploca resembled morphologically Thioploca ingrica, a brackish water species from a Danish fjord. The diameters of individual trichomes were 3 to 5.6 μm; the diameters of complete Thioploca filaments ranged from 18 to 75 μm. The cell lengths ranged from 1.2 to 3.8 μm. In transmission electron microscope specimens stained with uranyl acetate, dense intracellular particles were found, which did not show any positive signals for phosphorus and sulfur in an X-ray analysis. The 16S rRNA gene of the Thioploca from Lake Biwa was amplified by using newly designed Thioploca-specific primers (706-Thioploca, Biwa160F, and Biwa829R) in combination with general bacterial primers in order to avoid nonspecific amplification of contaminating bacterial DNA. Denaturing gradient gel electrophoresis (DGGE) analysis of the three overlapping PCR products resulted in single DGGE bands, indicating that a single 16S rRNA gene had been amplified. With the same method, the Thioploca from Lake Constance was examined. The 16S rRNA sequence was verified by performing fluorescence in situ hybridization targeted at specific motifs of the Lake Biwa Thioploca. Positive signals were obtained with the bacterial probe EUB-338, the γ-proteobacterial probe GAM42a, and probe Biwa829 targeting the Lake Biwa Thioploca. Based on the nearly complete 16S rRNA sequence and on morphological similarities, the Thioploca from Lake Biwa and the Thioploca from Lake Constance are closely related to T. ingrica and to each other.

scholarly journals Simultaneous Cellulose Degradation and Electricity Production by Enterobacter cloacae in a Microbial Fuel Cell

2009 ◽  
Vol 75 (11) ◽  
pp. 3673-3678 ◽  
Author(s):  
Farzaneh Rezaei ◽  
Defeng Xing ◽  
Rachel Wagner ◽  
John M. Regan ◽  
Tom L. Richard ◽  
...  
Keyword(s):  
16S Rrna ◽  
Microbial Fuel Cells ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Cellulose Degradation ◽  
Enterobacter Cloacae ◽  
Community Analysis ◽  
Electricity Production ◽  
Rrna Gene ◽  
16S Rrna Sequence ◽  
Gradient Gel Electrophoresis

ABSTRACT Electricity can be directly generated by bacteria in microbial fuel cells (MFCs) from many different biodegradable substrates. When cellulose is used as the substrate, electricity generation requires a microbial community with both cellulolytic and exoelectrogenic activities. Cellulose degradation with electricity production by a pure culture has not been previously demonstrated without addition of an exogenous mediator. Using a specially designed U-tube MFC, we enriched a consortium of exoelectrogenic bacteria capable of using cellulose as the sole electron donor. After 19 dilution-to-extinction serial transfers of the consortium, 16S rRNA gene-based community analysis using denaturing gradient gel electrophoresis and band sequencing revealed that the dominant bacterium was Enterobacter cloacae. An isolate designated E. cloacae FR from the enrichment was found to be 100% identical to E. cloacae ATCC 13047T based on a partial 16S rRNA sequence. In polarization tests using the U-tube MFC and cellulose as a substrate, strain FR produced 4.9 ± 0.01 mW/m2, compared to 5.4 ± 0.3 mW/m2 for strain ATCC 13047T. These results demonstrate for the first time that it is possible to generate electricity from cellulose using a single bacterial strain without exogenous mediators.

scholarly journals Characterization of a Culturable Alphaproteobacterial Symbiont Common to Many Marine Sponges and Evidence for Vertical Transmission via Sponge Larvae

2006 ◽  
Vol 72 (5) ◽  
pp. 3724-3732 ◽  
Author(s):  
Julie J. Enticknap ◽  
Michelle Kelly ◽  
Olivier Peraud ◽  
Russell T. Hill
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Marine Sponges ◽  
Rrna Gene ◽  
Surrounding Water ◽  
Axinella Corrugata ◽  
Gradient Gel Electrophoresis ◽  
Related Group

ABSTRACT A closely related group of alphaproteobacteria were found to be present in seven genera of marine sponges from several locations and were shown to be transferred between sponge generations through the larvae in one of these sponges. Isolates of the alphaproteobacterium were cultured from the sponges Axinella corrugata, Mycale laxissima, Monanchora unguifera, and Niphates digitalis from Key Largo, Florida; Didiscus oxeata and Monanchora unguifera from Discovery Bay, Jamaica; an Acanthostronglyophora sp. from Manado, Indonesia; and Microciona prolifera from the Cheasapeake Bay in Maryland. Isolates were very similar to each other on the basis of 16S rRNA gene sequence (>99% identity) and are closely related to Pseudovibrio denitrificans. The bacterium was never isolated from surrounding water samples and was cultured from larvae of M. laxissima, indicating that it is a vertically transmitted symbiont in this sponge. Denaturing gradient gel electrophoresis, 16S rRNA gene clone library analysis, and fluorescent in situ hybridization with probes specific to the alphaproteobacterium confirmed the presence of this bacterium in the M. laxissima larvae. The alphaproteobacterium was densely associated with the larvae rather than being evenly distributed throughout the mesohyl. This is the first report of the successful culture of a bacterial symbiont of a sponge that is transferred through the gametes.

scholarly journals Combined Phospholipid Biomarker-16S rRNA Gene Denaturing Gradient Gel Electrophoresis Analysis of Bacterial Diversity and Physiological Status in an Intertidal Microbial Mat

2004 ◽  
Vol 70 (11) ◽  
pp. 6920-6926 ◽  
Author(s):  
Laura Villanueva ◽  
Antoni Navarrete ◽  
Jordi Urmeneta ◽  
David C. White ◽  
Ricardo Guerrero
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Gel Electrophoresis ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Microbial Mat ◽  
Physiological Status ◽  
Rrna Gene ◽  
Microbial Composition ◽  
Lipid Biomarker ◽  
Gradient Gel Electrophoresis

ABSTRACT A combined lipid biomarker-16S rRNA gene denaturing gradient gel electrophoresis analysis was used to monitor changes in the physiological status, biomass, and microbial composition of a microbial mat. In the morning hours, an increase in the biomass of layers containing a high density of phototrophs and a decrease in the growth rate in the deep layers were observed. The combined approach also revealed differences in major groups of microorganisms, including green nonsulfur, gram-positive, and heterotrophic bacteria.

Denaturing Gradient Gel Electrophoresis Detects Bacterial and Cyaonbacterial Diversities in Biological Soil Crusts in a Semiarid Desert, China

2013 ◽  
Vol 726-731 ◽  
pp. 3680-3684
Author(s):  
Ying Zhang ◽  
Cheng You Cao ◽  
Peng Zhang
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Gel Electrophoresis ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Biological Soil Crusts ◽  
Rrna Gene ◽  
Sandy Land ◽  
Specific Primers ◽  
Soil Crusts ◽  
Gradient Gel Electrophoresis

The purpose of this study is to assess the application of denaturing gradient gel electrophoresis (DGGE) for analyzing the bacterial and cyanobacterial diversities of biological soil crusts (BSCs) in sandy land. Soil microbial DNA was extracted from BSCs under different plantations in Horqin Sandy Land of Northeast China. 16S rRNA gene fragments from bacteria and cyanobacteria were amplified by universal bacterial and cyanobacteria-specific primers. Fourteen and six prominent bands were detected in the bacterial and cyanobacterial DGGE profiles, respectively. These bands were excised, cloned and sequenced. Phylogenetic analysis classified the bacterial sequences into the following main groups:Escherichia,Bacillus,Paenibacillus,Shigella, andPseudomonas. The cyanobacterial sequences were classified asMicrocoleus,LeptolyngbyaandHaslea. Our study suggests that DGGE is a useful technique for detecting dominant species compositions of bacterial and cyanobacterial communities in biological soil crusts, and specific primers are recommended for PCR of 16S rRNA gene fragments.

Sign in / Sign up

Export Citation Format

Share Document