scholarly journals Evolutionary Implications of Anoxygenic Phototrophy in the Bacterial Phylum Candidatus Palusbacterota (WPS-2)

2019 ◽  
Author(s):  
Lewis M. Ward ◽  
Tanai Cardona ◽  
Hannah Holland-Moritz
Keyword(s):  
Photochemical Reaction ◽  
Close Association ◽  
Reaction Centers ◽  
Phylogenomic Analysis ◽  
Metagenomic Sequencing ◽  
Type Ii ◽  
Ecological Significance ◽  
Anoxygenic Photosynthesis ◽  
New Family ◽  
Related Proteins

AbstractGenome-resolved environmental metagenomic sequencing has uncovered substantial previously unrecognized microbial diversity relevant for understanding the ecology and evolution of the biosphere, providing a more nuanced view of the distribution and ecological significance of traits including phototrophy across diverse niches. Recently, the capacity for bacteriochlorophyll-based anoxygenic photosynthesis has been found in the uncultured bacterial WPS-2 clade that are in close association with boreal moss. Here, we use phylogenomic analysis to investigate the diversity and evolution of phototrophic WPS-2. We demonstrate that phototrophic WPS-2 show significant genetic and metabolic divergence from other phototrophic and non-phototrophic lineages. The genomes of these organisms encode a completely new family of anoxygenic Type II photochemical reaction centers and other phototrophy-related proteins that are both phylogenetically and structurally distinct from those found in previously described phototrophs. We propose the name Candidatus Palusbacterota for the phylum-level aerobic WPS-2 clade which contains phototrophic lineages, from the Latin for “bog bacteria”, distinguishing it from the anaerobic, non-phototrophic sister phylum Candidatus Eremiobacterota for “desert bacteria”, typically found in dry environments.

scholarly journals Multiple light-induced reactions of cytochromes b and c in Rhodopseudomonas spheroides

1969 ◽  
Vol 114 (4) ◽  
pp. 793-799 ◽  
Author(s):  
O. T. G. Jones
Keyword(s):  
Cytochrome C ◽  
Cytochrome B ◽  
Photochemical Reaction ◽  
Room Temperature ◽  
Close Association ◽  
Antimycin A ◽  
Reaction Centre ◽  
Difference Spectra ◽  
Cytochromes C ◽  
Rhodopseudomonas Spheroides

Illumination of chromatophore preparations from Rhodopseudomonas spheroides causes the oxidation of a cytochrome c and a slight oxidation of a cytochrome b with a maximum at 560nm. When illuminated in the presence of antimycin A the oxidation of cytochrome c was more pronounced and cytochrome b560 was reduced; the dark oxidation of cytochrome b560 was biphasic in the presence of succinate, but not in the presence of NADH, a less effective reductant. Split-beam spectroscopy showed that, in addition to the reduction of cytochrome b560, another pigment with maxima at 565 and 537nm. was reduced and was more rapidly oxidized in the dark than cytochrome b560. This pigment, tentatively identified as cytochrome b565, was also detected in spectra at 77°k, after brief illumination at room temperature; the maxima at 77°k were at 562 and 536nm. In the absence of antimycin A, light caused a transient reduction of cytochrome b565 and an oxidation of cytochrome b560. Dark oxidation of b565 was rapid, even in the presence of antimycin A and succinate. Difference spectra, at 77°k, of ascorbate-reduced minus succinate-reduced chromatophores or of anaerobic succinate-reduced minus aerobic succinate-reduced chromatophores suggested that two cytochromes c were present, with maxima at 547 and 549nm. When chromatophores frozen at 77°k were illuminated both these cytochromes c were oxidized, indicating a close association with the photochemical reaction centre. A scheme involving two reaction centres is proposed to explain these results.

scholarly journals Cellulosomal Scaffoldin-Like Proteins fromRuminococcus flavefaciens

2001 ◽  
Vol 183 (6) ◽  
pp. 1945-1953 ◽  
Author(s):  
Shi-You Ding ◽  
Marco T. Rincon ◽  
Raphael Lamed ◽  
Jennifer C. Martin ◽  
Sheila I. McCrae ◽  
...  
Keyword(s):  
Direct Interaction ◽  
Rumen Bacterium ◽  
Type I ◽  
Gene Products ◽  
Type Ii ◽  
Direct Demonstration ◽  
Anchoring Protein ◽  
Domain Of Unknown Function ◽  
Signature Sequences ◽  
Related Proteins

ABSTRACT Two tandem cellulosome-associated genes were identified in the cellulolytic rumen bacterium, Ruminococcus flavefaciens. The deduced gene products represent multimodular scaffoldin-related proteins (termed ScaA and ScaB), both of which include several copies of explicit cellulosome signature sequences. The scaB gene was completely sequenced, and its upstream neighbor scaAwas partially sequenced. The sequenced portion of scaAcontains repeating cohesin modules and a C-terminal dockerin domain. ScaB contains seven relatively divergent cohesin modules, two extremely long T-rich linkers, and a C-terminal domain of unknown function. Collectively, the cohesins of ScaA and ScaB are phylogenetically distinct from the previously described type I and type II cohesins, and we propose that they define a new group, which we designated here type III cohesins. Selected modules from both genes were overexpressed inEscherichia coli, and the recombinant proteins were used as probes in affinity-blotting experiments. The results strongly indicate that ScaA serves as a cellulosomal scaffoldin-like protein for severalR. flavefaciens enzymes. The data are supported by the direct interaction of a recombinant ScaA cohesin with an expressed dockerin-containing enzyme construct from the same bacterium. The evidence also demonstrates that the ScaA dockerin binds to a specialized cohesin(s) on ScaB, suggesting that ScaB may act as an anchoring protein, linked either directly or indirectly to the bacterial cell surface. This study is the first direct demonstration in a cellulolytic rumen bacterium of a cellulosome system, mediated by distinctive cohesin-dockerin interactions.

scholarly journals Soil microbes and oxygen influence the changes in bacterial community composition during swine carcass decomposition

2021 ◽  
Author(s):  
Michelle Miguel ◽  
Seon Ho Kim ◽  
Sang Suk Lee ◽  
Yong Il Cho
Keyword(s):  
Bacterial Community ◽  
16S Rrna ◽  
Community Composition ◽  
Soil Microbes ◽  
Close Association ◽  
Bacterial Community Composition ◽  
Alpha Diversity ◽  
Decomposition Process ◽  
Metagenomic Sequencing ◽  
Unsterilized Soil

Abstract Background Carcass decomposition is influenced by various factors such as temperature, humidity, microorganisms, invertebrates, and scavengers. Soil microbes play a significant role in the decomposition process. In this study, we investigated the changes in the bacterial community during carcass decomposition in soil with an intact microbial community and soil which was sterilized decomposed with and without oxygen access using 16s rRNA metagenomic sequencing. Results Based on the 16S rRNA metagenomic sequencing, a total of 988 operational taxonomic units (OTUs) representing 16 phyla and 533 genera were detected. The bacterial diversity varied across the based on the alpha diversity indices. The bacterial composition in the unsterilized soil – aerobic condition (U_A) and unsterilized soil – anaerobic condition (U_An) set-ups have higher alpha diversity than the other burial set-ups. Beta diversity analysis revealed a close association in the samples according to the burial type and decomposition day. Firmicutes was the dominant phylum across all samples regardless of the burial type and decomposition day. The bacterial community composition changed throughout the decomposition process in all burial set-up. Meanwhile, the genus Bacillus dominated the bacterial community towards the end of decomposition period. Conclusions Our results showed that bacterial community composition changed during carcass decomposition and was affected by the soil and oxygen access, with microorganisms belonging to phylum Firmicutes dominating the community.

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