scholarly journals Novel insights into the taxonomic diversity and molecular mechanisms of bacterial Mn(III) reduction

2019 ◽  
Author(s):  
Nadia Szeinbaum ◽  
Brook L. Nunn ◽  
Amanda R. Cavazos ◽  
Sean A. Crowe ◽  
Frank J. Stewart ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Molecular Mechanisms ◽  
Enrichment Culture ◽  
Taxonomic Diversity ◽  
Extracellular Electron Transfer ◽  
Aquatic Environments ◽  
Natural Environments ◽  
Biological Reduction ◽  
Lake Matano ◽  
C Complex

SummarySoluble ligand-bound Mn(III) can support anaerobic microbial respiration in diverse aquatic environments. Thus far, Mn(III) reduction has only been associated with certain Gammaproteobacteria. Here, we characterized microbial communities enriched from Mn-replete sediments of Lake Matano, Indonesia. Our results provide the first evidence for biological reduction of soluble Mn(III) outside the Gammaproteobacteria. Metagenome assembly and binning revealed a novel betaproteobacterium, which we designate “Candidatus Dechloromonas occultata.” This organism dominated the enrichment and expressed a porin-cytochrome c complex typically associated with iron-oxidizing Betaproteobacteria and a novel cytochrome c-rich protein cluster (Occ), including an undecaheme putatively involved in extracellular electron transfer. This occ gene cluster was also detected in diverse aquatic bacteria, including uncultivated Betaproteobacteria from the deep subsurface. These observations provide new insight into the taxonomic and functional diversity of microbially-driven Mn(III) reduction in natural environments.Originality-Significance StatementRecent observations suggest that Mn(III)-ligand complexes are geochemically important in diverse aquatic environments. Thus far, microbially-driven Mn(III) reduction has only been associated with Gammaproteobacteria encoding three-component outer-membrane porin-cytochrome c conduits. Here, we demonstrate that Betaproteobacteria dominate in abundance and with respect to protein expression during biologically-mediated Mn(III) reduction in an enrichment culture from an anoxic lacustrine system. Using metaproteomics, we detect for the first time that Betaproteobacteria express a two-component porin-cytochrome c conduit, and an uncharacterized extracellular undecaheme (11-heme) c-type cytochrome. Although this is the first definitive report of an undecaheme within the Betaproteobacteria, we find evidence that they are widespread in uncultivated strains. These results widen the phylogenetic diversity of Mn(III)-reducing bacteria, and provide new insights into potential molecular mechanisms for soluble Mn(III) reduction

scholarly journals A heterodimeric cytochrome c complex with a very low redox potential from an anaerobic ammonium-oxidizing enrichment culture

2010 ◽  
Vol 313 (1) ◽  
pp. 61-67 ◽  
Author(s):  
Saki Ukita ◽  
Takao Fujii ◽  
Daisuke Hira ◽  
Takashi Nishiyama ◽  
Tatsushi Kawase ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Redox Potential ◽  
Enrichment Culture ◽  
C Complex

scholarly journals SOME PROPERTIES OF A BACILLOMYCIN b-CYTOCHROME c COMPLEX

1951 ◽  
Vol 190 (1) ◽  
pp. 133-148
Author(s):  
Howard. Tint ◽  
Wilhelm. Reiss
Keyword(s):  
Cytochrome C ◽  
C Complex

scholarly journals A Brief Review of the Structure, Cytotoxicity, Synthesis, and Biodegradation of Microcystins

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2147
Author(s):  
Anjali Krishnan ◽  
Xiaozhen Mou
Keyword(s):  
Health Hazard ◽  
Aquatic Organisms ◽  
Water Soluble ◽  
Cyanobacterial Blooms ◽  
Aquatic Environments ◽  
Natural Environments ◽  
Exposure Pathway ◽  
Environmental Transformation ◽  
Cyclic Heptapeptide ◽  
Harmful Cyanobacterial Blooms

Harmful cyanobacterial blooms pose an environmental health hazard due to the release of water-soluble cyanotoxins. One of the most prevalent cyanotoxins in nature is microcystins (MCs), a class of cyclic heptapeptide hepatotoxins, and they are produced by several common cyanobacteria in aquatic environments. Once released from cyanobacterial cells, MCs are subjected to physical chemical and biological transformations in natural environments. MCs can also be taken up and accumulated in aquatic organisms and their grazers/predators and induce toxic effects in several organisms, including humans. This brief review aimed to summarize our current understanding on the chemical structure, exposure pathway, cytotoxicity, biosynthesis, and environmental transformation of microcystins.

Shedding new light on the regulation of complementary chromatic adaptation

2008 ◽  
Vol 3 (4) ◽  
pp. 351-358 ◽  
Author(s):  
Beronda Montgomery
Keyword(s):  
Molecular Basis ◽  
Molecular Mechanisms ◽  
Cellular Morphology ◽  
Chromatic Adaptation ◽  
Natural Environments ◽  
Complementary Chromatic Adaptation ◽  
Light Sensing ◽  
Central Elements ◽  
Over 40 Years

AbstractComplementary chromatic adaptation (CCA) is a light-dependent acclimation process that occurs in cyanobacteria and likely is related to increased fitness of these organisms in natural environments. Although CCA has been studied for over 40 years, significant advances in our understanding of the molecular foundations of CCA are still emerging. In this minireview, I explore recently reported developments that include novel insights into the molecular mechanisms utilized in the photoregulation of pigmentation and the molecular basis of light-dependent changes in cellular morphology, which are central elements of the process of CCA. I also discuss future avenues of study that are expected to lead to additional progress in our understanding of CCA and our general appreciation of light sensing and photomorphogenesis in cyanobacteria.

scholarly journals Heavily Armed Ancestors: CRISPR Immunity and Applications in Archaea with a Comparative Analysis of CRISPR Types in Sulfolobales

Biomolecules ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1523
Author(s):  
Isabelle Anna Zink ◽  
Erika Wimmer ◽  
Christa Schleper
Keyword(s):  
Comparative Analysis ◽  
Molecular Mechanisms ◽  
Model Organisms ◽  
Special Focus ◽  
Natural Environments ◽  
Type I ◽  
Accessory Proteins ◽  
Type Iii

Prokaryotes are constantly coping with attacks by viruses in their natural environments and therefore have evolved an impressive array of defense systems. Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) is an adaptive immune system found in the majority of archaea and about half of bacteria which stores pieces of infecting viral DNA as spacers in genomic CRISPR arrays to reuse them for specific virus destruction upon a second wave of infection. In detail, small CRISPR RNAs (crRNAs) are transcribed from CRISPR arrays and incorporated into type-specific CRISPR effector complexes which further degrade foreign nucleic acids complementary to the crRNA. This review gives an overview of CRISPR immunity to newcomers in the field and an update on CRISPR literature in archaea by comparing the functional mechanisms and abundances of the diverse CRISPR types. A bigger fraction is dedicated to the versatile and prevalent CRISPR type III systems, as tremendous progress has been made recently using archaeal models in discerning the controlled molecular mechanisms of their unique tripartite mode of action including RNA interference, DNA interference and the unique cyclic-oligoadenylate signaling that induces promiscuous RNA shredding by CARF-domain ribonucleases. The second half of the review spotlights CRISPR in archaea outlining seminal in vivo and in vitro studies in model organisms of the euryarchaeal and crenarchaeal phyla, including the application of CRISPR-Cas for genome editing and gene silencing. In the last section, a special focus is laid on members of the crenarchaeal hyperthermophilic order Sulfolobales by presenting a thorough comparative analysis about the distribution and abundance of CRISPR-Cas systems, including arrays and spacers as well as CRISPR-accessory proteins in all 53 genomes available to date. Interestingly, we find that CRISPR type III and the DNA-degrading CRISPR type I complexes co-exist in more than two thirds of these genomes. Furthermore, we identified ring nuclease candidates in all but two genomes and found that they generally co-exist with the above-mentioned CARF domain ribonucleases Csx1/Csm6. These observations, together with published literature allowed us to draft a working model of how CRISPR-Cas systems and accessory proteins cross talk to establish native CRISPR anti-virus immunity in a Sulfolobales cell.

Involvement of electrostatic interactions in cytochrome c complex formations

Biochimie ◽  
1994 ◽  
Vol 76 (6) ◽  
pp. 515-523 ◽  
Author(s):  
F. Guerlesquin ◽  
A. Dolla ◽  
M. Bruschi
Keyword(s):  
Cytochrome C ◽  
Electrostatic Interactions ◽  
C Complex ◽  
Complex Formations

scholarly journals Co-ordinate decrease in the expression of the mitochondrial genome and nuclear genes for mitochondrial proteins in the lactation-induced mitochondrial hypotrophy of rat brown fat

1995 ◽  
Vol 308 (3) ◽  
pp. 749-752 ◽  
Author(s):  
I Martin ◽  
M Giralt ◽  
O Viñas ◽  
R Iglesias ◽  
T Mampel ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Mitochondrial Genome ◽  
Cytochrome C Oxidase ◽  
Molecular Mechanisms ◽  
Uncoupling Protein ◽  
Relative Content ◽  
Nuclear Genes ◽  
Mitochondrial Proteins ◽  
Mrna Levels ◽  
Brown Adipose

The relative abundance of the mitochondrial-encoded mRNAs for cytochrome c oxidase subunit II and NADH dehydrogenase subunit I was lower in brown adipose tissue (BAT) from lactating rats than in virgin controls. This decrease was in parallel with a significant decrease in mitochondrial 16 S rRNA levels and in the relative content of mitochondrial DNA in the tissue. BAT from lactating rats showed lowered mRNA expression of the nuclear-encoded genes for the mitochondrial uncoupling protein, subunit IV of cytochrome c oxidase and the adenine nucleotide translocase isoforms ANT1 and ANT2, whereas mRNA levels for the ATP synthase beta-subunit were unchanged. However, the relative content of this last protein was lower in BAT mitochondria from lactating rats than in virgin controls. It is concluded that lactation-induced mitochondrial hypotrophy in BAT is associated with a co-ordinate decrease in the expression of the mitochondrial genome and nuclear genes for mitochondrial proteins. This decrease is caused by regulatory events acting at different levels, including pre- and post-transcriptional regulation. BAT appears to be a useful model with which to investigate the molecular mechanisms involved in the co-ordination of the expression of the mitochondrial and nuclear genomes during mitochondrial biogenesis.

scholarly journals Taxonomic diversity and toxicological assessment of Cyanobacteria in Moroccan inland waters

2009 ◽  
Vol 22 (3) ◽  
pp. 435-449 ◽  
Author(s):  
Mountasser Douma ◽  
Mohammed Loudiki ◽  
Brahim Oudra ◽  
Khadija Mouhri ◽  
Youness Ouahid ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
High Performance ◽  
Taxonomic Diversity ◽  
Inland Waters ◽  
Aquatic Environments ◽  
Structural Variants ◽  
Toxicological Assessment ◽  
Photodiode Array ◽  
Toxic Bloom ◽  
First Time

AbstractResearch on the ecology, biodiversity and toxicology of cyanobacteria in Moroccan inland waters has been carried out since 1994. The results demonstrate the existence of several taxa of cyanobacteria. Most of them are toxic, bloom‑forming species present in various water bodies of the country. The present study follows upon this earlier work and spans the 2003-2006 period. The major aim was to update and supplement the existing national cyanobacteria inventory and to isolate new toxic strains. During the study period, more than 40 aquatic environments were visited and sampled.Almost 300 taxa of cyanobacteria were recorded. They belonged to 3 orders, 14 families and 46 genera. Among these, about 78 taxa are recorded for the first time in Morocco; 29 strains of cyanobacteria were successfully isolated and cultured in the laboratory. All the collected cyanobacteria, including natural blooms, mats, and cultured strains, were analyzed for toxicity and hepatotoxins (microcystins) were quantified. Using the High-performance liquid chromatography technique coupled to photodiode array (PDA) detector (HPLC-PDA), four samples ofMicrocystisblooms showed the presence of microcystins (MCs), with a concentration ranging between 1.87 and 64.4 µg•g‑1MC‑LR eq (microcystin-LR equivalents). A total of five different structural variants of MCs were detected (MC-LR, -RR, -YR, -FR, -WR). Furthermore, 3 of 29 isolates were confirmed as MCs producing strains.The results show that the widening of the survey led to a better knowledge of the diversity of cyanobacteria. The taxonomic inventory was greatly increased and several cyanobacteria strains were characterized for their toxicity. The results should be useful as a database for the identification of various aquatic environments contaminated by cyanobacterial toxins (microcystins), which represent a potent sanitary risk for human and animals.

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