scholarly journals Effect of Lactose on Soluble-glucan Production and on the Ultrastructure of Sclerotium rolfsii Sacc. Grown in Submerged Culture

Microbiology ◽  
2000 ◽  
Vol 81 (1) ◽  
pp. 145-149 ◽  
Author(s):  
Y. Okon ◽  
I. Chet ◽  
Naomi Kislev ◽  
Y. Henis
Keyword(s):  
Carbon Source ◽  
Submerged Culture ◽  
Sole Carbon Source ◽  
Synthetic Medium ◽  
Sclerotium Rolfsii ◽  
Dry Weight ◽  
Solid Media

SUMMARY A significant increase in mycelial dry weight and a decrease in production of extracellular glucan were observed when lactose was added to a submerged culture of Sclerotium rolfsii grown in a liquid glucose-synthetic medium. When added as a sole carbon source, lactose at 2·5% (w/v) induced the formation of dark, spherical, compact bodies. The ultrastructure of these bodies is compared with that of sclerotia formed on solid media.

scholarly journals Isolation and Characterization of a Mutant of the Marine Bacterium Alcanivorax borkumensis SK2 Defective in Lipid Biosynthesis

2010 ◽  
Vol 76 (9) ◽  
pp. 2884-2894 ◽  
Author(s):  
Efraín Manilla-Pérez ◽  
Alvin Brian Lange ◽  
Stephan Hetzler ◽  
Marc Wältermann ◽  
Rainer Kalscheuer ◽  
...  
Keyword(s):  
Carbon Source ◽  
Sole Carbon Source ◽  
Marine Bacterium ◽  
Neutral Lipids ◽  
Nile Red ◽  
Dry Weight ◽  
Wax Ester ◽  
Gene Encoding ◽  
Isolation And Characterization ◽  
Key Enzyme

ABSTRACT In many microorganisms, the key enzyme responsible for catalyzing the last step in triacylglycerol (TAG) and wax ester (WE) biosynthesis is an unspecific acyltransferase which is also referred to as wax ester synthase/acyl coenzyme A (acyl-CoA):diacylglycerol acyltransferase (WS/DGAT; AtfA). The importance and function of two AtfA homologues (AtfA1 and AtfA2) in the biosynthesis of TAGs and WEs in the hydrocarbon-degrading marine bacterium Alcanivorax borkumensis SK2 have been described recently. However, after the disruption of both the AtfA1 and AtfA2 genes, reduced but substantial accumulation of TAGs was still observed, indicating the existence of an alternative TAG biosynthesis pathway. In this study, transposon-induced mutagenesis was applied to an atfA1 atfA2 double mutant to screen for A. borkumensis mutants totally defective in biosynthesis of neutral lipids in order to identify additional enzymes involved in the biosynthesis of these lipids. At the same time, we have searched for a totally TAG-negative mutant in order to study the function of TAGs in A. borkumensis. Thirteen fluorescence-negative mutants were identified on Nile red ONR7a agar plates and analyzed for their abilities to synthesize lipids. Among these, mutant 2 M131 was no longer able to synthesize and accumulate TAGs if pyruvate was used as the sole carbon source. The transposon insertion was localized in a gene encoding a putative cytochrome c family protein (ABO_1185). Growth and TAG accumulation experiments showed that the disruption of this gene resulted in the absence of TAGs in 2 M131 but that growth was not affected. In cells of A. borkumensis SK2 grown on pyruvate as the sole carbon source, TAGs represented about 11% of the dry weight of the cells, while in the mutant 2 M131, TAGs were not detected by thin-layer and gas chromatography analyses. Starvation and lipid mobilization experiments revealed that the lipids play an important role in the survival of the cells. The function of neutral lipids in A. borkumensis SK2 is discussed.

scholarly journals A synthetic medium for the selection of yeasts able to utilize fatty acids as the sole carbon source.

1996 ◽  
Vol 42 (1) ◽  
pp. 87-91 ◽  
Author(s):  
ESTEBAN C. DELL'ANGELICA ◽  
DANIEL MILIKOWSKI ◽  
DANIEL A. SAENZ ◽  
CARLOS A. STELLA ◽  
EUGENIA H. RAMOS ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Carbon Source ◽  
Sole Carbon Source ◽  
Synthetic Medium ◽  
Selection Of

Ochratoxin production by Aspergillus ochraceus as affected by methionine and structurally related compounds

1983 ◽  
Vol 29 (5) ◽  
pp. 536-540 ◽  
Author(s):  
N. Lisker ◽  
N. Paster ◽  
I. Chet
Keyword(s):  
Radial Growth ◽  
Sole Carbon Source ◽  
Synthetic Medium ◽  
Methionine Sulfoxide ◽  
Dry Weight ◽  
Aspergillus Ochraceus ◽  
Inhibitory Effects ◽  
Methionine Sulfone ◽  
Initial Ph ◽  
Related Compounds

When 10−2 M of L- or D-methionine was added to a synthetic medium containing xylose as the sole carbon source, ochratoxin production by Aspergillus ochraceus was strongly inhibited. At that concentration methionine derivatives, e.g., α-methyl-DL-methionine, DL-methionine sulfoxide, and L-methionine sulfone, did not inhibit ochratoxin production, whereas DL-methionine S-methyl sulfonium chloride (MMSC) inhibited ochratoxin production to a large extent. L-Methionine, as well as MMSC, also completely inhibited sclerotia formation, while D-methionine and DL-methionine sulfoxide caused only a partial inhibition. At lower concentrations (10−3 and 10−4 M), none of the compounds exhibited inhibitory effects. In cases where strong ochratoxin inhibition was detected, fungal radial growth or mycelial dry weight was inhibited by only 10–25%, while the initial pH of the medium dropped from ~6.5 to ~4.4–5.0. Adjustment of the initial pH of media supplemented with 10−2 ML-methionine, D-methionine, or MMSC to a pH of ~7.8 did not change the inhibitory effects on ochratoxin production in media containing L-methionine. On the other hand, sclerotia formation was restored in all three treatments.

Effect of dimethyl sulfoxide on the sclerotia of Sclerotium rolfsii

1971 ◽  
Vol 17 (3) ◽  
pp. 429-431 ◽  
Author(s):  
J. H. Melhuish Jr. ◽  
G. A. Bean
Keyword(s):  
Growth Rate ◽  
Dimethyl Sulfoxide ◽  
Synthetic Medium ◽  
Sclerotium Rolfsii ◽  
Dry Weight ◽  
Free Medium ◽  
Sulfur Containing ◽  
Sulfur Containing Compounds

Sclerotium rolfsii was grown on a synthetic medium containing from 0 to 20 000 ppm dimethyl sulfoxide (DMSO). Growth rate and sclerotial production decreased with increased DMSO level. With 2000 ppm DMSO in the medium, sclerotial production decreased 45%. The sclerotial size and dry weight increased with DMSO level up to 8000 ppm and decreased at concentrations of 12 000 ppm, or more. Sclerotia, when produced on media containing DMSO and transferred to DMSO-free medium, produced normal mycelia and sclerotia. Sulfur-containing compounds similar to DMSO did not affect sclerotial production.

Rhizosphere competence of benomyl-tolerant mutants of Trichoderma spp.

1988 ◽  
Vol 34 (5) ◽  
pp. 694-696 ◽  
Author(s):  
Jaleed S. Ahmad ◽  
Ralph Baker
Keyword(s):  
Growth Rate ◽  
Carbon Source ◽  
Trichoderma Harzianum ◽  
Sole Carbon Source ◽  
Linear Growth ◽  
Dry Weight ◽  
Linear Growth Rate ◽  
Wild Type ◽  
Trichoderma Spp ◽  
Rhizosphere Competence

Two strains of Trichoderma harzianum and one each of T. koningii, T. polysporum, and T. viride were mutated for tolerance to the fungicide benomyl. Rhizosphere competence index of several mutants of each strain and species was determined by the rhizosphere competence assay. Most of the mutants and not their wild type parents were rhizosphere competent. When the strains and species were grown in Czapek–Dox broth for 6 days with cellulose as sole carbon source, the mutants produced significantly higher dry weight than their parent wild types. Neither the mutants nor the wild types produced biomass in glucose comparable to that in cellulose. Evidence indicates that Trichoderma spp. were induced by mutation to increase their linear growth rate and to become rhizosphere competent. Tolerance to benomyl does not seem to be a necessary attribute of rhizosphere competence.

scholarly journals Bioconversion of biphenyl to a polyhydroxyalkanoate copolymer by Alcaligenes denitrificans A41

2020 ◽  
Author(s):  
Taito Yajima ◽  
Mizuki Nagatomo ◽  
Aiko Wakabayashi ◽  
Michio Sato ◽  
Seiichi Taguchi ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Carbon Source ◽  
Sole Carbon Source ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Nitrogen Sources ◽  
Dry Weight ◽  
Environmental Pollutant ◽  
Genes Encoding ◽  
Copolymer Poly

Abstract A polyhydroxyalkanoate (PHA) copolymer, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)], was biosynthesized from biphenyl as the sole carbon source using Alcaligenes (currently Achromobacter) denitrificans A41. This strain is capable of degrading polychlorinated biphenyls (PCBs) and biphenyl. This proof-of-concept of the conversion of aromatic chemicals such as the environmental pollutant PCBs/biphenyl to eco-friendly products such as biodegradable polyester PHA was inspired by the uncovering of two genes encoding PHA synthases in the A. denitrificans A41 genome. When the carbon/nitrogen (C/N) ratio was set at 21, the cellular P(3HB-co-3HV) content in strain A41 reached its highest value of 10.1% of the cell dry weight (CDW). A two-step cultivation protocol improved the accumulation of P(3HB-co-3HV) by up to 26.2% of the CDW, consisting of 13.0 mol% 3HV when grown on minimum salt medium without nitrogen sources. The highest cellular content of P(3HB-co-3HV) (47.6% of the CDW) was obtained through the two-step cultivation of strain A41 on biphenyl as the sole carbon source. The purified copolymer had ultra-high molecular weight (weight-average molecular weight of 3.5 × 106), as revealed through gel-permeation chromatography. Based on the genomic information related to both polymer synthesis and biphenyl degradation, we finally proposed a metabolic pathway for the production of P(3HB-co-3HV) associated with the degradation of biphenyl by strain A41.

scholarly journals ESTIMATION OF ANTIBACTERIAL EFFECT ON VIBRIO CHOLERAE (ON THE EXAMPLE OF THE SUBSTANCE ACETYL-N- CYSTEINE–L)

2019 ◽  
pp. 55-57
Author(s):  
O.V. Duvanova ◽  
B.N. Mishan′kin
Keyword(s):  
Minimum Inhibitory Concentration ◽  
Carbon Source ◽  
Vibrio Cholerae ◽  
Sole Carbon Source ◽  
Inhibitory Concentration ◽  
Antibacterial Effect ◽  
Synthetic Medium ◽  
Nutrient Media ◽  
Cholera Vibrio ◽  
El Tor

We studied the effect of the substance acetyl-N-cysteine-L on cholera Vibrio. Its minimum inhibitory concentration for the strains of Vibrio cholerae El Tor O1 and O139 serogroup was 1–2.5 mg/ml in solid nutrient media - Martin's agar (pH 7.6) and LB (pH 7.2), while in Bhascaran synthetic medium, using glucose (0.1per cent) as the sole carbon source, N-acetyl-β-D-glucosamine (0.05 per cent) or colloidal chitin (0.027 per cent) it was reduced to 50–250 μg/ml. The ability of the substance acetyl-N-cysteine-L substance to suppress the activity of the purified enzyme N-acetyl-β-D-glucosaminidase (chitobiasis) was found. Antibacterial effect detected of the substance acetyl-N-cysteine-L against the strains of Vibrio cholerae El Tor O1 and O139 serogroups with different epidemic significance (presence / absence of ctxAB and tcpA genes) indicates the advisability of considering the issue on the possibility of including this substance in composition of solution components used in the rehydration therapy of diarrheal diseases cases.

Cholesterol is accumulated by mycobacteria but its degradation is limited to non-pathogenic fast-growing mycobacteria

2000 ◽  
Vol 46 (9) ◽  
pp. 826-831 ◽  
Author(s):  
Yossef Av-Gay ◽  
Rafat Sobouti
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Carbon Source ◽  
Sole Carbon Source ◽  
Mycobacterial Infection ◽  
Growth Media ◽  
Bacillus Calmette Guerin ◽  
Liquid Media ◽  
Fast Growing ◽  
Solid Media ◽  
Slow Growing

In this report we show that fast-growing non-pathogenic mycobacteria degrade cholesterol from liquid media, and are able to grow on cholesterol as a sole carbon source. In contrast, slow-growing mycobacteria, including pathogenic Mycobacterium tuberculosis and bacillus Calmette-Guérin (BCG), do not degrade and use cholesterol as a carbon source. Nevertheless, pathogenic mycobacteria are able to uptake, modify, and accumulate cholesterol from liquid growth media, and form a zone of clearance around a colony when plated on solid media containing cholesterol. These data suggest that cholesterol may have a role in mycobacterial infection other than its use as carbon source.Key words: mycobacteria, cholesterol, biodegradation.

Effects of cysteine and structurally related compounds on ochratoxin production by Aspergillus ochraceus

1985 ◽  
Vol 31 (11) ◽  
pp. 973-976 ◽  
Author(s):  
N. Lisker ◽  
N. Paster ◽  
I. Chet
Keyword(s):  
Carbon Source ◽  
Sole Carbon Source ◽  
Synthetic Medium ◽  
Fungal Growth ◽  
Toxin Production ◽  
Aspergillus Ochraceus ◽  
Homocysteine Thiolactone ◽  
The Media ◽  
Related Compounds

Addition of 10−2 ML-cysteine, L-cystine, or S-ethyl-L-cysteine to a synthetic medium containing xylose as the sole carbon source did not decrease ochratoxin production by Aspergillus ochraceus. At that concentration, DL-homocysteine thiolactone HCl, DL-cysteine HCl, L-ethionine, S-methyl-L-cysteine, and glutathione (reduced) strongly inhibited ochratoxin production. DL-Homocysteine thiolactone HCl, DL-cysteine HCl, and L-ethionine also strongly inhibited fungal growth. At lower concentrations (10−3and 10−4 M) only L-ethionine decreased the toxin production. Ochratoxin inhibition caused by DL-homocysteine thiolactone HCl, DL-cysteine HCl, and glutathione was observed only in cases where the pH of the media was below 5.0. The inhibition caused by 10−3 M ethionine was partially prevented by the addition of 10−3 M methionine but this was not the case after the addition of S-methyl-L-cysteine to the medium.

Improved procedure and colorimetric test for the detection of ortho- and meta-cleavage of protocatechuate by Pseudomonas isolates

1974 ◽  
Vol 20 (7) ◽  
pp. 1059-1061 ◽  
Author(s):  
J. C. G. Ottow ◽  
W. Zolg
Keyword(s):  
Carbon Source ◽  
Yeast Extract ◽  
Sole Carbon Source ◽  
Synthetic Medium ◽  
Clear Cut ◽  
Colorimetric Test ◽  
Ring Fission ◽  
Cut Method

A sensitive and clear-cut method for the demonstration of ortho- and meta-cleavage of protocatechuate is described. Pseudomonas strains to be tested for the mode of ring fission should be grown on a synthetic medium containing p-hydroxybenzoate, quinate, or glucose–yeast extract as sole carbon source. Suspensions of these organisms are tested for ring-fission mechanism to detect the constitutive or inducible nature of protocatechuate 3,4-oxygenase.

Sign in / Sign up

Export Citation Format

Share Document