scholarly journals Non-Frankia Actinomycetes Isolated from Surface-Sterilized Roots of Casuarina equisetifolia Fix Nitrogen

2005 ◽  
Vol 71 (1) ◽  
pp. 460-466 ◽  
Author(s):  
Mar�a Vald�s ◽  
N�stor-Octavio P�rez ◽  
Paulina Estrada-de los Santos ◽  
Jes�s Caballero-Mellado ◽  
Juan Jos� Pe�a-Cabriales ◽  
...  

ABSTRACT Based on partial 16S sequences, we previously described a novel group of nonsymbiotic, acetylene reduction activity-positive actinomycetes which were isolated from surface-sterilized roots of Casuarina equisetifolia growing in Mexico. An amplified rRNA restriction analysis confirmed that these actinomycetes are distinct from Frankia, a finding substantiated by a 16S rRNA gene phylogenetic analysis of two of the Mexican isolates. Further support for these actinomycetes being separate from Frankia comes from the very low DNA-DNA homology that was found. Nevertheless, the Mexican isolates may be diazotrophs based not only on their ability to grow in N-free medium and reduce acetylene to ethylene but also on the results from 15N isotope dilution analysis and the finding that a nifH gene was PCR amplified. A comparison of the nifH sequences from the various isolates showed that they are closely related to nifH from Frankia; the similarity was 84 to 98% depending on the host specificity group. An analysis of complete 16S rRNA gene sequences demonstrated that the two strains analyzed in detail are most closely related to actinobacteria in the Thermomonosporaceae and the Micromonosporaceae.

2004 ◽  
Vol 54 (5) ◽  
pp. 1439-1452 ◽  
Author(s):  
Yaacov Davidov ◽  
Edouard Jurkevitch

A phylogenetic analysis of Bdellovibrio-and-like organisms (BALOs) was performed. It was based on the characterization of 71 strains and on all consequent 16S rRNA gene sequences available in databases, including clones identified by data-mining, totalling 120 strains from very varied biotopes. Amplified rDNA restriction analysis (ARDRA) accurately reflected the diversity and phylogenetic affiliation of BALOs, thereby providing an efficient screening tool. Extensive phylogenetic analysis of the 16S rRNA gene sequences revealed great diversity within the Bdellovibrio (>14 % divergence) and Bacteriovorax (>16 %) clades, which comprised nine and eight clusters, respectively, exhibiting more than 3 % intra-cluster divergence. The clades diverged by more than 20 %. The analysis of conserved 16S rRNA secondary structures showed that Bdellovibrio contained motifs atypical of the δ-Proteobacteria, suggesting that it is ancestral to Bacteriovorax. While none of the Bdellovibrio strains were of marine origin, Bacteriovorax included separate soil/freshwater and marine-specific groups. On the basis of their extensive diversity and the large distance separating the groups, it is proposed that Bacteriovorax starrii be placed into a new genus, Peredibacter gen. nov., with Peredibacter starrii A3.12T (=ATCC 15145T=NCCB 72004T) as its type strain. Also proposed is a redefinition of the Bdellovibrio and the Bacteriovorax–Peredibacter lineages as two different families, i.e. ‘Bdellovibrionaceae’ and a new family, Bacteriovoracaceae. Also, a re-evaluation of oligonucleotides targeting BALOs is presented, and the implications of the large diversity of these organisms and of their distribution in very different environments are discussed.


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.


2008 ◽  
Vol 74 (10) ◽  
pp. 3198-3215 ◽  
Author(s):  
Enoma O. Omoregie ◽  
Vincent Mastalerz ◽  
Gert de Lange ◽  
Kristina L. Straub ◽  
Andreas Kappler ◽  
...  

ABSTRACT In this study we determined the composition and biogeochemistry of novel, brightly colored, white and orange microbial mats at the surface of a brine seep at the outer rim of the Chefren mud volcano. These mats were interspersed with one another, but their underlying sediment biogeochemistries differed considerably. Microscopy revealed that the white mats were granules composed of elemental S filaments, similar to those produced by the sulfide-oxidizing epsilonproteobacterium “Candidatus Arcobacter sulfidicus.” Fluorescence in situ hybridization indicated that microorganisms targeted by a “Ca. Arcobacter sulfidicus”-specific oligonucleotide probe constituted up to 24% of the total the cells within these mats. Several 16S rRNA gene sequences from organisms closely related to “Ca. Arcobacter sulfidicus” were identified. In contrast, the orange mat consisted mostly of bright orange flakes composed of empty Fe(III) (hydr)oxide-coated microbial sheaths, similar to those produced by the neutrophilic Fe(II)-oxidizing betaproteobacterium Leptothrix ochracea. None of the 16S rRNA gene sequences obtained from these samples were closely related to sequences of known neutrophilic aerobic Fe(II)-oxidizing bacteria. The sediments below both types of mats showed relatively high sulfate reduction rates (300 nmol·cm−3·day−1) partially fueled by the anaerobic oxidation of methane (10 to 20 nmol·cm−3·day−1). Free sulfide produced below the white mat was depleted by sulfide oxidation within the mat itself. Below the orange mat free Fe(II) reached the surface layer and was depleted in part by microbial Fe(II) oxidation. Both mats and the sediments underneath them hosted very diverse microbial communities and contained mineral precipitates, most likely due to differences in fluid flow patterns.


2011 ◽  
Vol 61 (9) ◽  
pp. 2292-2297 ◽  
Author(s):  
Guo-Zhen Zhao ◽  
Jie Li ◽  
Hai-Yu Huang ◽  
Wen-Yong Zhu ◽  
Dong-Jin Park ◽  
...  

A Gram-positive, aerobic, actinobacterial strain with rod-shaped spores, designated YIM 63158T, was isolated from the surface-sterilized roots of Artemisia annua L. collected from Yunnan province, south-west China. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain YIM 63158T belonged to the genus Pseudonocardia. The closest neighbours were ‘Pseudonocardia sichuanensis’ KLBMP 1115 (99.9 % 16S rRNA gene sequence similarity), Pseudonocardia adelaidensis EUM 221T (99.1 %) and Pseudonocardia zijingensis DSM 44774T (98.8 %); sequence similarities to other members of the genus Pseudonocardia ranged from 98.6 to 94.4 %. The chemotaxonomic characteristics, such as the cell-wall diaminopimelic acid, whole-cell sugars, fatty acid components and major menaquinones, suggested that the isolate belonged to the genus Pseudonocardia. The G+C content of the genomic DNA was 73.3 mol%. On the basis of physiological, biochemical and chemotaxonomic data, including low DNA–DNA relatedness between the isolate and other members of the genus Pseudonocardia, it is proposed that strain YIM 63158T represents a novel species in this genus, with the name Pseudonocardia kunmingensis sp. nov. The type strain is YIM 63158T ( = DSM 45301T  = CCTCC AA 208081T).


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