Which microorganisms have sterols

Hill, R. Distribution of sewage indicated by Clostridium perfringens at a deep-water disposal site after cessation of sewage disposal. Howington, J. Distribution of the McMurdo station sewage plume. Hughes, K. Influence of seasonal environmental variables on the distribution of presumptive fecal coliforms around an Antarctic research station. Distribution of sewage pollution around a maritime Antarctic research station indicated by fecal coliforms, Clostridium perfringens and fecal sterol markers.

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Your message to the editors. Your email only if you want to be contacted back. Edited by: Martin G. Welander ude. This article was submitted to Microbial Physiology and Metabolism, a section of the journal Frontiers in Microbiology. Received Apr 5; Accepted Jun 9. The use, distribution or reproduction in other forums is permitted, provided the original author s or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice.

No use, distribution or reproduction is permitted which does not comply with these terms. This article has been cited by other articles in PMC. Abstract Sterols are essential components of eukaryotic cells whose biosynthesis and function has been studied extensively.

Keywords: lipid biosynthesis, sterols, biomarkers, squalene epoxidase, oxidosqualene cyclase, myxobacteria, methanotrophs, planctomycetes. Introduction Sterols are tetracyclic triterpenoid lipids that are required by all eukaryotes for critical cellular functions including maintaining membrane fluidity, phagocytosis, stress tolerance, and cell signaling Bloch, ; Swan and Watson, ; Castoreno et al.

Open in a separate window. Figure 1. Materials and methods Bioinformatics analyses Homologs of the M. Table 1 Bacterial strains tested for sterol biosynthesis. Figure 2. Table 2 Bacterial genomes that contain oxidosqualene cyclase homologs. Figure 3. Phylogenetic analysis of genomic and metagenomic Osc sequences To analyze the phylogeny of the new bacterial Osc homologs identified in our database searches, we generated two maximum likelihood phylogenetic trees.

Figure 4. Figure 5. Lipid analysis of potential sterol producers Our identification of Osc homologs in bacterial genomes demonstrates that the potential for sterol synthesis exists in a variety of bacteria.

Table 3 Sterols identified in bacterial strains. Table 4 Identification of sterol biosynthesis genes in bacterial genomes. Figure 6. Figure 7. Sterol production in the methanotrophs The lipid profiles of the four Methylococcales species tested were similar to what was previously observed in M.

Figure 8. Sterol production in other bacterial species We also observed production of cycloartenol in one Bacteriodetes species, F. Figure 9. Cycloartenol vs. Discussion Sterol biosynthesis is primarily viewed as a eukaryotic feature that is rarely observed in the bacterial domain.

Author contributions JW acquired and analyzed data and was involved in editing the manuscript. Conflict of interest statement The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Acknowledgments We would like to thank Prof.

References Abe I. Site-directed mutagenesis of conserved aromatic residues in rat squalene epoxidase. Eudoraea adriatica gen. Nucleic Acids Res. A distinct pathway for tetrahymanol synthesis in bacteria. Cloning and characterization of ERG25, the Saccharomyces cerevisiae gene encoding C-4 sterol methyl oxidase. Steroids and squalene in Methylococcus capsulatus grown on methane. Nature , — Cholesterol: evolution of structure and function , in Biochemistry of Lipids, Lipoproteins, and Membranes , eds Vance D.

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Berlin: Springer-Verlag; , — Revised taxonomy of the methanotrophs: description of Methylobacter gen. Biomarker evidence for green and purple sulphur bacteria in a stratified Palaeoproterozoic sea. Transcriptional regulation of phagocytosis-induced membrane biogenesis by sterol regulatory element binding proteins.

Phylogenomics of sterol synthesis: insights into the origin, evolution, and diversity of a key eukaryotic feature.

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Hypotheses for the origin and early evolution of triterpenoid cyclases. Geobiology 5 , 19— Phylogenetic analysis of the triterpene cyclase protein family in prokaryotes and eukaryotes suggests bidirectional lateral gene transfer. Characterization of the Saccharomyces cerevisiae ERG26 gene encoding the C-3 sterol dehydrogenase C-4 decarboxylase involved in sterol biosynthesis.

Characterization of the Saccharomyces cerevisiae ERG27 gene encoding the 3-keto reductase involved in C-4 sterol demethylation. A simple, fast, and accurate algorithm to estimate large phylogenies by maximum likelihood. Draft genomes of gammaproteobacterial methanotrophs isolated from terrestrial ecosystems. Genome Announc. Plant sterols and the membrane environment. Trends Plant Sci. Occurrence of hopanoid lipids in anaerobic Geobacter species.

FEMS Microbiol. Comparative genomic analysis of fruiting body formation in Myxococcales. Complete genome sequence of the fruiting myxobacterium Corallococcus coralloides DSM Plesiocystis pacifica gen.

Enhygromyxa salina gen. Taxonomic characterization of new alkaliphilic and alkalitolerant methanotrophs from soda lakes of the Southeastern Transbaikal region and description of Methylomicrobium buryatense sp. Classification of halo alkali philic and halo alkali tolerant methanotrophs provisionally assigned to the genera Methylomicrobium and Methylobacter and emended description of the genus Methylomicrobium.

Methylosarcina lacus sp. Isolation and characterization of halotolerant alkaliphilic methanotrophic bacteria from Tuva Soda Lakes. Draft genome sequence of the methane-oxidizing bacterium Methylococcus capsulatus Texas. Sterols in a unicellular relative of the metazoans. Bioinformatics 23 , — Interactive Tree Of Life v2: online annotation and display of phylogenetic trees made easy. Interactive tree of life iTOL v3: an online tool for the display and annotation of phylogenetic and other trees.

Oxidosqualene cyclase second-sphere residues profoundly influence the product profile. Chembiochem 5 , — Fossil steroids record the appearance of Demospongiae during the Cryogenian period. Studies on the taxonomy of the Myxobacterales. The resulting stenone or sterol-Coic acid is then catabolized according to two subpathways: cleavage of the sterol side chain and degradation of the steroid nucleus.

Steroids constitute a lipid-linked class, comprising sterols, metabolites, hormones and bile acids. Selective cleavage of the sterol side chain delivers derivatives which are industrially usable for production of active steroids. This cleavage has attracted much attention and studied for various microorganisms. In the two cases, the issued derivatives are then catabolized throughout two subpathways: the side chain cleavage and the steroid nucleus degradation.

Meanwhile, they are still considered as attractive themes. The present minireview concerns these two enzymes with a critical focus on new data; especially divergent items are discussed.

A survey on the microbial catabolism of sterols is introduced in this minireview, in order to illustrate relevant points. The microbial catabolism of steroids comprising sterols has been the target of many studies since approximately the mid of the 20th century. Early data can be documented from reviews published in the 80th and 90th years e. Characterizations of bacterial gene clusters, involved in the degradation of steroids, have been reported, since roughly the year e.

Horinouchi et al. Comamonas testosteroni Horinouchi et al. Gram-positive bacteria, comprising the actinobacterial genera, Gordonia , Mycobacterium , Nocardia and Rhodococcus , are steroid potent degradors, particularly active in the catabolism of cholesterol and plant sterols Murohisa and Iida a , b ; Donova ; Drzyzga et al.

Generally, the sterol catabolism pathway is conserved and widespread in Actinobacteria Bergstrand et al. However, it was demonstrated that R. Other related Actinobacteria appear to start the sterol catabolism with C26 oxidation Wilbrink, van der Geize and Dijkhuizen Aerobic sterol catabolism in Actinobacteria.

Dashed arrows: several reactions. B Sterol catabolism in R. Following the initial step, Actinobacteria proceed to catabolize the produced sterol derivative throughout two subpathways: side chain cleavage and the steroid nucleus degradation. Numerous reports e. Ahmad et al. These enzymes are usually active on 3-ketosteroids of the androstane C19 , pregnane C21 or C22 steroid derivatives Itagaki, Wakabayashi and Hatta ; Petrusma, Dijkhuizen and van der Geize ; de las Heras et al.

ChOx has been isolated from various microbial sources, comprising Gram-negative and Gram-positive bacteria MacLachlan et al. Most of the microorganisms described as ChOx producers, produce it in extracellular form, released into their growth media.

Both enzyme forms are believed to be of the same gene. The cell-linked form is extractible with non-ionic detergent, as Triton X polyethylene glycol octylphenyl ether and Lubrol PX polyethylene glycol monododecyl ether. ChOx is among the most studied enzymes. The reader can consult reviews, concerned with the enzyme structural features Vrielink and Ghisla , its biotechnological applications Pollegioni, Piubelli and Molla and the enzyme physiological functions Kreit and Sampson Nonetheless, reports regarding ChOx production, purification, molecular characterization and genetic analysis have been continuously published.

A minireview on the engineering of bacterial ChOxs aimed at improving their physicochemical and catalytic properties was recently published Moradpour and Ghasemian ChOx is monomer of around 60 kDa, containing one molecule of FAD, fixed into the active site cavity with non-covalent bonds class I or covalent bonds class II. The enzyme forms of the two classes have no significant sequence homology Sampson and Vrielink ; Doukyu ChOx is bifunctional Fig. However, the sterol side chain length modulates the enzyme activity level; in vitro , it is most active with cholesterol.

In sterol-catabolizing microorganism, one role of ChOx is nutritional, whether the microorganism lives in the nature or in host cell, as Rhodococcus equi in macrophage.

Meanwhile, ChOx has been considered as a virulence factor in R. The enzyme role in pathogenesis appears to be due to its ability to alter the physical structure of the lipid membrane by converting the membrane cholesterol into cholestemycobacteria to catabolize cholesterolnone Sampson and Vrielink ; Kreit and Sampson However, it is not yet clear where this membrane alteration fits into the pathway of infection, and which are exactly the lipid altering enzymes that with ChOx contribute to the pathogen propagation.

Besides, it was hypothesized that ChOx pimE is an antifungal sensor for the biosynthesis of the macrolide pimaricin in Streptomyces natalensis Aparicio and Martin The mechanism by which the supposed enzyme action triggers biosynthesis of this macrolide remains unknown Aparicio et al.

Streptomyces natalensis produces an extracellular ChOx. In the strain natural environment, this enzyme is released free, and could act on ergosterol-containing membrane of the antagonist fungal cells. It is possible to suggest that PimE and pimaricin, which acts on the same site, have a cooperative antifungal effect that causes alteration of the fungal cell membrane. Besides, the capacity of mycobacteria of the tuberculosis complex to catabolize cholesterol throughout infection and disease became evident Pandey and Sassetti ; Chang et al.

HsD has been characterized as the main or the sole enzyme that initiates the catabolism of cholesterol or other sterols in Mycobacteria and Nocardia Wipperman, Sampson and Thomas Confusing attributions of ChOx species are reviewed hereafter, together with reports describing HsD from Mycobacteria and Nocardia :.

The enzyme producing it was named cholesterol dehydrogenase, as the authors assumed that its reaction product, 5-cholestenone, isomerizes readily to the more stable derivative, 4-cholestenone. Microorganisms of the Mycobacterium rhodochrous group comprising the Stadtman's bacterium were recognized as R. However, the Stadtman's strain was reported as Nocardia cholesterolicum of this group in the survey of Halpern on industrial enzymes from microbial sources.

The Stadtman's enzyme is actually a ChOx, requiring molecular oxygen. According to these references, the ChOx-producing N.

ChOx-producing strains of N. The ChOx-producing strains of N. Sojo et al. Fast-growing Mycobacteria were supposed to synthesize cell-surface-linked ChOxs on the bases of western blot analysis Wilmanska et al. Antigenic similarity of the examined Mycobacterial proteins was noticed with ChOx from the mold Schizophyllum commune , but not with experimentally characterized ChOx from Streptomyces. ChOx activity of these proteins was not measured. It would be possible that the examined proteins are ChOxs; however, the described data are insufficient to support this possibility.

Rvc was heterologously expressed in E scherichia coli. The expressed protein is monomer of an apparent molecular mass of 43 kD. A cholesterol dehydrogenase was isolated from cells of Nocardia sp. Ch Horinouchi, Ishizuka and Deppu The enzyme gene was heterologously over expressed in Streptomyce s spp.

The nucleotide sequence together with the determined amino acid sequence reveled that this dehydrogenase consists of amino acid residues, corresponding to a molecular mass of about 40 kDa.

That of the HsD from M. Cholesterol-dependent regulation of HsD in the Nocardia strain occurs at the level of transcription. This dehydrogenase was further characterized for determination of serum cholesterol Kishi et al. In silico analysis identified the Msmeg and Msmeg genes in M. The expression of the Msmeg was shown to be inducible by growth on cholesterol, whereas the expression of Msmeg gene was constitutive.

When both genes were expressed in E. Moreover, Msmeg -defected mutant was not affected in the production of 4-cholestenone from cholesterol. However, Msmeg -defected mutant showed a drastic reduction in the production of 4-cholesten3-one, but still able to grow on cholesterol, due to a second HsD.

Experimentally, it was demonstrated that M. Sterolibacterium denitrificans is capable to catabolize cholesterol in anoxic or oxic environment, following the same catabolic pathway Chiang et al. The dehydrogenase AcmA initiates the cholesterol catabolism by transforming it into 4-cholestenone. Another fingerprint of the SDR enzymes is the highly conserved catalytic triad, serine-tyrosine-lysine, found in the middle part of AcmA, although the serine residue is variable.

It was suggested that the members of this enzyme family have similar reaction mechanisms. Brzostek et al. In these reports, choD was considered as a gene encoding ChOx, but the enzyme activity was not characterized.

The M. A transposon mutant of M. Molecular characterization of this GPL showed that it is deacetylated at its rhamnonnose 6-deoxy-L-mannose and 6-L-deoxytalose units. The authors suggested that Rvc or Msmeg controls acetylation of their respective cell surface GPL, and thus establishes the natural hydrophobicity of the molecule.

Actually, Mycobacterial cell-surface-exposed GPLs are involved in pathogenesis.