scholarly journals Biogeography, Evolution, and Diversity of Epibionts in Phototrophic Consortia

2004 ◽  
Vol 70 (8) ◽  
pp. 4821-4830 ◽  
Author(s):  
Jens Glaeser ◽  
Jörg Overmann

ABSTRACT Motile phototrophic consortia are highly regular associations in which numerous cells of green sulfur bacteria surround a flagellated colorless β-proteobacterium in the center. To date, seven different morphological types of such consortia have been described. In addition, two immotile associations involving green sulfur bacteria are known. By employing a culture-independent approach, different types of phototrophic consortia were mechanically isolated by micromanipulation from 14 freshwater environments, and partial 16S rRNA gene sequences of the green sulfur bacterial epibionts were determined. In the majority of the lakes investigated, different types of phototrophic consortia were found to co-occur. In all cases, phototrophic consortia with the same morphology from the same habitat contained only a single epibiont phylotype. However, morphologically indistinguishable phototrophic consortia collected from different lakes contained different epibionts. Overall, 19 different types of epibionts were detected in the present study. Whereas the epibionts within one geographic region were very similar (Dice coefficient, 0.582), only two types of epibionts were found to occur on both the European and North American continents (Dice coefficient, 0.190). None of the epibiont 16S rRNA gene sequences have been detected so far in free-living green sulfur bacteria, suggesting that the interaction between epibionts and chemotrophic bacteria in the phototrophic consortia is an obligate interaction. Based on our phylogenetic analysis, the epibiont sequences are not monophyletic. Thus, the ability to form symbiotic associations either arose independently from different ancestors or was present in a common ancestor prior to the radiation of green sulfur bacteria and the transition to the free-living state in independent lineages. The present study thus demonstrates that there is great diversity and nonrandom geographical distribution of phototrophic consortia in the natural environment.

2003 ◽  
Vol 69 (7) ◽  
pp. 3739-3750 ◽  
Author(s):  
Jens Glaeser ◽  
Jörg Overmann

ABSTRACT A dense population of the phototrophic consortium “Pelochromatium roseum” was investigated in the chemocline of a temperate holomictic lake (Lake Dagow, Brandenburg, Germany). Fluorescence in situ hybridization revealed that the brown epibionts of “P. roseum” constituted up to 37% of the total bacterial cell number and up to 88% of all green sulfur bacteria present in the chemocline. Specific amplification of 16S rRNA gene fragments of green sulfur bacteria and denaturing gradient gel electrophoresis fingerprinting yielded a maximum of four different DNA bands depending on the year of study, indicating that the diversity of green sulfur bacteria was low. The 465-bp 16S rRNA gene sequence of the epibiont of “P. roseum” was obtained after sorting of individual consortia by micromanipulation, followed by a highly sensitive PCR. The sequence obtained represents a new phylotype within the radiation of green sulfur bacteria. Maximum light-dependent H14CO3 − fixation in the chemocline in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea suggested that there was anaerobic autotrophic growth of the green sulfur bacteria. The metabolism of the epibionts was further studied by determining stable carbon isotope ratios (δ13C) of their specific biomarkers. Analysis of photosynthetic pigments by high-performance liquid chromatography revealed the presence of high concentrations of bacteriochlorophyll (BChl) e and smaller amounts of BChl a and d and chlorophyll a in the chemocline. Unexpectedly, isorenieratene and β-isorenieratene, carotenoids typical of other brown members of the green sulfur bacteria, were absent. Instead, four different esterifying alcohols of BChl e were isolated as biomarkers of green sulfur bacterial epibionts, and their δ13C values were determined. Farnesol, tetradecanol, hexadecanol, and hexadecenol all were significantly enriched in 13C compared to bulk dissolved and particulate organic carbon and compared to the biomarkers of purple sulfur bacteria. The difference between the δ13C values of farnesol, the major esterifying alcohol of BChl e, and CO2 was −7.1%, which provides clear evidence that the mode of growth of the green sulfur bacterial epibionts of “P. roseum” in situ is photoautotrophic.


2004 ◽  
Vol 54 (6) ◽  
pp. 2049-2051 ◽  
Author(s):  
Philip Hugenholtz ◽  
Erko Stackebrandt

Sphaerobacter thermophilus was originally classified as the deepest branching member of the phylum Actinobacteria (high-G+C, Gram-positive bacteria) based on 16S rRNA gene comparative analysis. However, the analysis lacked suitable outgroups, and additional 16S rRNA gene sequences indicate that it is most closely related to Thermomicrobium roseum, which it also resembles phenotypically. Furthermore, both species are reproducibly affiliated with the phylum Chloroflexi (green non-sulfur bacteria), despite T. roseum currently being classified in its own phylum, the Thermomicrobia. Transfer of Sphaerobacter to the class Thermomicrobia, and transfer of the class Thermomicrobia to the phylum Chloroflexi, are proposed. Descriptions for the phylum Chloroflexi and the class Thermomicrobia are emended to reflect the proposed changes in classification.


2007 ◽  
Vol 74 (3) ◽  
pp. 624-632 ◽  
Author(s):  
Ann K. Manske ◽  
Uta Henßge ◽  
Jens Glaeser ◽  
Jörg Overmann

ABSTRACT The Black Sea is the largest extant anoxic water body on Earth. Its oxic-anoxic boundary is located at a depth of 100 m and is populated by a single phylotype of marine green sulfur bacteria. This organism, Chlorobium sp. strain BS-1, is extraordinarily low light adapted and can therefore serve as an indicator of deep photic zone anoxia (A. K. Manske, J. Glaeser, M. M. M. Kuypers, and J. Overmann, Appl. Environ. Microbiol. 71:8049-8060, 2005). In the present study, two sediment cores were retrieved from the bottom of the Black Sea at depths of 2,006 and 2,162 m and were analyzed for the presence of subfossil DNA sequences of BS-1 using ancient-DNA methodology. Using optimized cultivation media, viable cells of the BS-1 phylotype were detected only at the sediment surface and not in deeper layers. In contrast, green sulfur bacterial 16S rRNA gene fragments were amplified from all the sediment layers investigated, including turbidites. After separation by denaturing gradient gel electrophoresis and sequencing, 14 different sequence types were distinguished. The sequence of BS-1 represented only a minor fraction of the amplification products and was found in 6 of 22 and 4 of 26 samples from the 2,006- and 2,162-m stations, respectively. Besides the sequences of BS-1, three additional phylotypes of the marine clade of green sulfur bacteria were detected. However, the majority of sequences clustered with groups from freshwater habitats. Our results suggest that a considerable fraction of green sulfur bacterial chemofossils did not originate in a low-light marine chemocline environment and therefore were likely to have an allochthonous origin. Thus, analysis of subfossil DNA sequences permits a more differentiated interpretation and reconstruction of past environmental conditions if specific chemofossils of stenoec species, like Chlorobium sp. strain BS-1, are employed.


2020 ◽  
Author(s):  
CC Kim ◽  
WJ Kelly ◽  
ML Patchett ◽  
GW Tannock ◽  
Z Jordens ◽  
...  

© 2017 IUMS. A novel anaerobic pectinolytic bacterium (strain 14T) was isolated from human faeces. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain 14T belonged to the family Ruminococcaceae, but was located separately from known clostridial clusters within the taxon. The closest cultured relative of strain 14T was Acetivibrio cellulolyticus (89.7% sequence similarity). Strain 14T shared ~99% sequence similarity with cloned 16S rRNA gene sequences from uncultured bacteria derived from the human gut. Cells were Gram-stain-positive, non-motile cocci approximately 0.6μm in diameter. Strain 14T fermented pectins from citrus peel, apple, and kiwifruit as well as carbohydrates that are constituents of pectins and hemicellulose, such as galacturonic acid, xylose, and arabinose. TEM images of strain 14T, cultured in association with plant tissues, suggested extracellular fibrolytic activity associated with the bacterial cells, forming zones of degradation in the pectin-rich regions of middle lamella. Phylogenetic and phenotypic analysis supported the differentiation of strain 14T as a novel genus in the family Ruminococcaceae. The name Monoglobus pectinilyticus gen. nov., sp. nov. is proposed; the type strain is 14T (JCM 31914T=DSM 104782T).


2007 ◽  
Vol 73 (20) ◽  
pp. 6682-6685 ◽  
Author(s):  
Daniel P. R. Herlemann ◽  
Oliver Geissinger ◽  
Andreas Brune

ABSTRACT The bacterial candidate phylum Termite Group I (TG-1) presently consists mostly of “Endomicrobia,” which are endosymbionts of flagellate protists occurring exclusively in the hindguts of termites and wood-feeding cockroaches. Here, we show that public databases contain many, mostly undocumented 16S rRNA gene sequences from other habitats that are affiliated with the TG-1 phylum but are only distantly related to “Endomicrobia.” Phylogenetic analysis of the expanded data set revealed several diverse and deeply branching lineages comprising clones from many different habitats. In addition, we designed specific primers to explore the diversity and environmental distribution of bacteria in the TG-1 phylum.


2005 ◽  
Vol 71 (10) ◽  
pp. 6308-6318 ◽  
Author(s):  
Helen A. Vrionis ◽  
Robert T. Anderson ◽  
Irene Ortiz-Bernad ◽  
Kathleen R. O'Neill ◽  
Charles T. Resch ◽  
...  

ABSTRACT The geochemistry and microbiology of a uranium-contaminated subsurface environment that had undergone two seasons of acetate addition to stimulate microbial U(VI) reduction was examined. There were distinct horizontal and vertical geochemical gradients that could be attributed in large part to the manner in which acetate was distributed in the aquifer, with more reduction of Fe(III) and sulfate occurring at greater depths and closer to the point of acetate injection. Clone libraries of 16S rRNA genes derived from sediments and groundwater indicated an enrichment of sulfate-reducing bacteria in the order Desulfobacterales in sediment and groundwater samples. These samples were collected nearest the injection gallery where microbially reducible Fe(III) oxides were highly depleted, groundwater sulfate concentrations were low, and increases in acid volatile sulfide were observed in the sediment. Further down-gradient, metal-reducing conditions were present as indicated by intermediate Fe(II)/Fe(total) ratios, lower acid volatile sulfide values, and increased abundance of 16S rRNA gene sequences belonging to the dissimilatory Fe(III)- and U(VI)-reducing family Geobacteraceae. Maximal Fe(III) and U(VI) reduction correlated with maximal recovery of Geobacteraceae 16S rRNA gene sequences in both groundwater and sediment; however, the sites at which these maxima occurred were spatially separated within the aquifer. The substantial microbial and geochemical heterogeneity at this site demonstrates that attempts should be made to deliver acetate in a more uniform manner and that closely spaced sampling intervals, horizontally and vertically, in both sediment and groundwater are necessary in order to obtain a more in-depth understanding of microbial processes and the relative contribution of attached and planktonic populations to in situ uranium bioremediation.


2006 ◽  
Vol 56 (11) ◽  
pp. 2579-2582 ◽  
Author(s):  
Jee-Min Lim ◽  
Che Ok Jeon ◽  
Dong-Jin Park ◽  
Li-Hua Xu ◽  
Cheng-Lin Jiang ◽  
...  

Strain B538T is a Gram-positive, motile, rod-shaped bacterium, which was isolated from Xinjiang province in China. This organism grew optimally at 30–35 °C and pH 8.0–8.5. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain B538T belonged to the genus Paenibacillus and chemotaxonomic data (DNA G+C content, 47.0 mol%; major isoprenoid quinone, MK-7; cell wall type, A1γ meso-diaminopimelic acid; major fatty acids, anteiso-C15 : 0 and C16 : 0) supported affiliation of the isolate with the genus Paenibacillus. Comparative 16S rRNA gene sequence analyses showed that the isolate was most closely related to Paenibacillus glycanilyticus DS-1T, with 16S rRNA gene sequence similarity of 98.1 %; sequence similarities to other members of the genus Paenibacillus used in the phylogenetic tree were less than 96.5 %. The DNA–DNA relatedness between strain B538T and P. glycanilyticus DS-1T was about 8.0 %. On the basis of physiological and molecular properties, strain B538T (=KCTC 3952T=DSM 16970T) is proposed as the type strain of a novel species within the genus Paenibacillus, for which the name Paenibacillus xinjiangensis sp. nov. is proposed.


2004 ◽  
Vol 54 (5) ◽  
pp. 1799-1803 ◽  
Author(s):  
Jung-Hoon Yoon ◽  
Soo-Hwan Yeo ◽  
In-Gi Kim ◽  
Tae-Kwang Oh

Two Gram-negative, motile, non-spore-forming and slightly halophilic rods (strains SW-145T and SW-156T) were isolated from sea water of the Yellow Sea in Korea. Strains SW-145T and SW-156T grew optimally at 37 and 30–37 °C, respectively, and in the presence of 2–6 % (w/v) NaCl. Strains SW-145T and SW-156T were chemotaxonomically characterized as having ubiquinone-9 as the predominant respiratory lipoquinone and C16 : 0, C18 : 1 ω9c, C16 : 1 ω9c and C12 : 0 3-OH as the major fatty acids. The DNA G+C contents of strains SW-145T and SW-156T were 58 and 57 mol%, respectively. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains SW-145T and SW-156T fell within the evolutionary radiation enclosed by the genus Marinobacter. The 16S rRNA gene sequences of strains SW-145T and SW-156T were 94·8 % similar. Strains SW-145T and SW-156T exhibited 16S rRNA gene sequence similarity levels of 94·3–98·1 and 95·4–97·7 %, respectively, with respect to the type strains of all Marinobacter species. Levels of DNA–DNA relatedness, together with 16S rRNA gene sequence similarity values, indicated that strains SW-145T and SW-156T are members of two species that are distinct from seven Marinobacter species with validly published names. On the basis of phenotypic properties and phylogenetic and genotypic distinctiveness, strains SW-145T (=KCTC 12185T=DSM 16070T) and SW-156T (=KCTC 12184T=DSM 16072T) should be placed in the genus Marinobacter as the type strains of two distinct novel species, for which the names Marinobacter flavimaris sp. nov. and Marinobacter daepoensis sp. nov. are proposed.


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