Metabolic blocks in the degradation of β‐sitosterol by a plasmid‐cured strain of <i>Arthrobacter oxydans</i>

Rk, Dutta; Mk, Roy; Hd, Singh

doi:10.1002/jobm.3620320305

Cited by 14 publications

(2 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The amount of triglycerides increased during the studied decay period, suggesting fungal esterification of fatty acids. The steroid ketones also increased during wood decay, probably because they are among the first products of oxidative degradation of sitosterol and other eucalypt sterols (18,47). The constant value for biomass of C. subvermispora (0.25 to 0.45%) throughout wood decay suggests continued fungal activity even after a colonization phase, as reported for other wood-colonizing fungi (22).…”

Section: Discussionmentioning

confidence: 52%

Production of New Unsaturated Lipids during Wood Decay by Ligninolytic Basidiomycetes

Gutiérrez

Río

Martinez-Inigo

et al. 2002

Appl Environ Microbiol

View full text Add to dashboard Cite

Lipids were analyzed by gas chromatography-mass spectrometry for a 7-week in vitro decay of eucalypt wood by four ligninolytic basidiomycetes. The sound wood contained up to 75 mg of lipophilic compounds per 100 g of wood. Hydrolysis of sterol esters, which represented 38% of total wood lipids, occurred during the fungal decay. The initial increase of linoleic and other free unsaturated fatty acids paralleled the decrease of sterol esters. Moreover, new lipid compounds were found at advanced stages of wood decay that were identified from their mass spectra as unsaturated dicarboxylic acids consisting of a long aliphatic chain attached to the C-3 position of itaconic acid. These dicarboxylic acids were especially abundant in the wood treated with Ceriporiopsis subvermispora (up to 24 mg per 100 g of wood) but also were produced by Phlebia radiata, Pleurotus pulmonarius, and Bjerkandera adusta. We hypothesize that three main alkylitaconic acids (tetradecylitaconic, cis-7-hexadecenylitaconic, and hexadecylitaconic acids) are synthesized by fungi in condensation reactions involving palmitic, oleic, and stearic acids. We suggest that both wood unsaturated fatty acids (present in free form or released from esters during natural decay) and unsaturated metabolites synthesized by fungi could serve as a source for peroxidizable lipids in lignin degradation by white rot basidiomycetes.Fungi produce a variety of lipids including fatty acids in free or esterified form, e.g., glycerides, phospholipids, glycolipids, sterol esters, sphingolipids, or simple esters, as well as other lipids, e.g., free sterols, sterol glycosides, and hydrocarbons (46,54,56). Vegetative mycelium (from pure cultures) and fruit bodies of basidiomycetes differ in both lipid content and fatty acid profiles. Linoleic (18:2 9c,12c ), oleic (18:1 9c ), and palmitic (16:0) acids are the main fatty acids in most cases. Linoleic acid is very abundant in fruit bodies and may account for as much as 70 to 80% of the lipids present (1,42,48,49). Other saturated and unsaturated fatty acids are present in basidiomycetes at lower levels. As reported for other filamentous fungi, unsaturated fatty acids could help basidiomycetes adapt to low growth temperatures (11,12). These fatty acids also may have a role in lignin degradation.Lipid peroxidation reactions could be a part of the lignin degradation process by white rot basidiomycetes. When unsaturated fatty acids are oxidized in the presence of manganese peroxidase (MnP), a ligninolytic peroxidase that oxidizes Mn 2ϩ to Mn 3ϩ , lipid hydroperoxides and free radicals are formed. This reaction is considered to be sufficient for lignin degradation by some ligninolytic fungi, e.g., Ceriporiopsis (syn. Poria) subvermispora, that lack lignin peroxidase (LiP) (4, 31-33). LiP, which has a high redox potential that enables direct oxidation of nonphenolic lignin units, was described in the white rot fungus Phanerochaete chrysosporium together with MnP (37). However, LiP has not been detected in some efficient lignin-degrading...

show abstract

Section: Discussionmentioning

confidence: 52%

Production of New Unsaturated Lipids during Wood Decay by Ligninolytic Basidiomycetes

Gutiérrez

Río

Martinez-Inigo

et al. 2002

Appl Environ Microbiol

View full text Add to dashboard Cite

show abstract

“…The ability of microorganisms to reduce 17-keto-to 17b hydroxysteroids was first reported in Saccharomyces cerevisiae, during the transformation of androst-4-ene-3,17-dione to testosterone (Charney and Herzog, 1967). Subsequently, the ability to carry out 17b-reduction of AD was reported for a variety of microorganisms of different taxonomy, including Mycobacterium, Pediococcus, Brevibacterium, Bacillus, Arthrobacter, Lactobacillus and Nocardia (Wix et al, 1968;Uwajima et al, 1973;Mahato and Mukherjee, 1984;Dutta et al, 1992;Kumar et al, 2001). But, very few microbial 17b-OH SDHs were isolated and characterized.…”

Section: Introductionmentioning

confidence: 99%

Highlight on Engineering Mycobacterium smegmatis for testosterone production

Sood

Singh

Shakarad

et al. 2016

Microbial Biotechnology

View full text Add to dashboard Cite

Role of plasmid pJL1 of Arthrobacter oxydans 317 in the degradation of β‐sitosterol

Dutta

Roy

Singh

1992

J. Basic Microbiol.

Self Cite

View full text Add to dashboard Cite

Arthrobacter oxydans 3 17 is a plasmid (pJL1)-harbouring organism capable of complete degradation of p-sitosterol, 4-androstene-3,17-dione (AD) and 1,4-androstadiene-3,17-dione (ADD). Plasmid-cured strain A . o.uvdaizs 317 A1 obtained by treatment of A. oxydans 317 with sodium dodecylsulphate (DUTTA et al. 1989) is capable of only partial degradation of 0-sitosterol side chain and incapable of utilizing AD and ADD. Conjugation experiments were carried out using A . oxyduns 317 Al as the recipient and A. o.xjukms 317 as the donor of pJLl plasmid. A transconjugant strain A . oxydans 317 TC containing pJLl plasmid was obtained. The transconjugant was able to form 9 a-hydroxy-4-androstene-3,17-dione (9a-hydroxy AD) from p-sitosterol and AD, and to utilize ADD for growth but it could not convert AD to ADD. It was proposed that pJLl is involved in the conversion of 3-oxochol-4-en-24-oic acid to AD and in the 9a-hydroxylation of the steroid nucleus but it is not connected with 1,2-dehydrogenation, a critical reaction step in steroid ring opening.Bacterial strains lacking either 9a-hydroxylase or 1,2-dehydrogenase or both are considered important in sterol biotransformation for production of AD and ADD provided that the strains are capable of complete elimination of C-17 alkyl sidechain of the sterol (MARTIN 1977). Though the enzymology of each step of sterol sidechain cleavage is not known, accumulation of intermediary sterol metabolites with intact steroid nucleus and partially cleaved sterol side chain have been reported (KNIGHT et al. 1980, HILL et al. 1982, JEKKEL et al. 1989. Plasmid mediated catabolic degradation of many organic compounds are known t'oday. However, there is an acute lack of information regarding the role of plasmids in sterol degradation, TENNESON et al. (1979) suggested the possible role of plasmids in complete degradation of the steroid ring structure.Arthrobucter oxyduns 3 17 is a plasmid harbouring organism (SARMAH e t ul. 1989) capable of complete degradation of P-sitosterol (GOSWAMI et al. 1982P-sitosterol (GOSWAMI et al. , 1983P-sitosterol (GOSWAMI et al. , 1984. Arthrobacter 317 AL, a plasmid-cured strain obtained from A . oxydans 317 by treatment with acridine orange was shown to be incapable of steroid ring degradation and complete cleavage of p-sitosterol side chain to form AD (SARMAH et al. 1989). In a previous communication (DUTTA et 01. 1992), the authors reported the work on the degradation of P-sitosterol by another plasmid-cured strain A . oxydans 317 Al and demonstrated the existence of metabolic blocks in the conversion of 3-oxochol-4-en-24-oic acid to AD and in 12-dehydrogenation and 9a-hydroxylation of the steroid ring structure. In this communication, the transfer of plasmid pJLl from A . oxyduns 3 17 to A . oxydans 3 17 Al through conjugation and the resulting changes in the metabolic pattern of p-sitosterol degradation in the transconjugant are reported providing clear evidence for the involvement of plasmid in sterol transformation. Materials and methodsOrganisms: 4. ...

show abstract

Metabolic blocks in the degradation of β‐sitosterol by a plasmid‐cured strain of Arthrobacter oxydans

Cited by 14 publications

References 15 publications

Production of New Unsaturated Lipids during Wood Decay by Ligninolytic Basidiomycetes

Production of New Unsaturated Lipids during Wood Decay by Ligninolytic Basidiomycetes

Highlight on Engineering Mycobacterium smegmatis for testosterone production

Role of plasmid pJL1 of Arthrobacter oxydans 317 in the degradation of β‐sitosterol

Contact Info

Product

Resources

About