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Fulltext Comparative metabolomics of Phialemonium curvatum as an omnipotent fungus cultivated on crude palm oil versus glucose

Zamani AI, Barig S, Ibrahim S, Mohd Yusof H, Ibrahim J, Low JYS, et al.

Microb Cell Fact, 2020 Sep 09;19(1):179.
PMID: 32907579 DOI: 10.1186/s12934-020-01434-w

BACKGROUND: Sugars and triglycerides are common carbon sources for microorganisms. Nonetheless, a systematic comparative interpretation of metabolic changes upon vegetable oil or glucose as sole carbon source is still lacking. Selected fungi that can grow in acidic mineral salt media (MSM) with vegetable oil had been identified recently. Hence, this study aimed to investigate the overall metabolite changes of an omnipotent fungus and to reveal changes at central carbon metabolism corresponding to both carbon sources.
RESULTS: Targeted and non-targeted metabolomics for both polar and semi-polar metabolites of Phialemonium curvatum AWO2 (DSM 23903) cultivated in MSM with palm oil (MSM-P) or glucose (MSM-G) as carbon sources were obtained. Targeted metabolomics on central carbon metabolism of tricarboxylic acid (TCA) cycle and glyoxylate cycle were analysed using LC-MS/MS-TripleQ and GC-MS, while untargeted metabolite profiling was performed using LC-MS/MS-QTOF followed by multivariate analysis. Targeted metabolomics analysis showed that glyoxylate pathway and TCA cycle were recruited at central carbon metabolism for triglyceride and glucose catabolism, respectively. Significant differences in organic acids concentration of about 4- to 8-fold were observed for citric acid, succinic acid, malic acid, and oxaloacetic acid. Correlation of organic acids concentration and key enzymes involved in the central carbon metabolism was further determined by enzymatic assays. On the other hand, the untargeted profiling revealed seven metabolites undergoing significant changes between MSM-P and MSM-G cultures.
CONCLUSIONS: Overall, this study has provided insights on the understanding on the effect of triglycerides and sugar as carbon source in fungi global metabolic pathway, which might become important for future optimization of carbon flux engineering in fungi to improve organic acids production when vegetable oil is applied as the sole carbon source.

Matched MeSH terms: Ascomycota/growth & development*
Succession patterns of fungi associated to wound-induced agarwood in wild Aquilaria malaccensis revealed from quantitative PCR assay

Mohamed R, Jong PL, Nurul Irdayu I

World J Microbiol Biotechnol, 2014 Sep;30(9):2427-36.
PMID: 24840100 DOI: 10.1007/s11274-014-1668-2

Aquilaria malaccensis produces agarwood in response to wounding and fungal attack. However, information is limited regarding Aquilaria's interaction with its diverse fungal community. In this study, time-related changes of three natural fungal colonizers in two wounded wild A. malaccensis were tracked, beginning a few hours after wounding up to 12 months. Using species-specific primers derived from their nrITS sequences in quantitative real-time PCR (qPCR), we quantified the amount of Cunninghamella bainieri, Fusarium solani and Lasiodiplodia theobromae. Because time is a major factor affecting agarwood quantity and quality, 14 wood samples were collected at different time points, i.e., 0-18 h, 2-13 days, 2-18 weeks, and 6-12 months after wounding. qPCR data revealed that the abundance of the three species decreased over time. The fungi were detected in high numbers during the first few hours and days after wounding (40- to 25,000-fold higher levels compared with initial counts) and in low numbers (<1- to 3,200-fold higher than initially) many months later. Consistent with its role in defense response, the accumulation of secondary metabolites at the wounding site could have caused the decline in fungal abundance. Succession patterns of the two trees were not identical, indicating that fungal populations may have been affected by tree environment and wound microclimate. Our results are important for understanding the diversity of microbial community in wild Aquilaria species and their association to wound-induced agarwood formation. Fungi could be secondary triggers to agarwood production in situations where trees are wounded in attempt to induce agarwood.

Matched MeSH terms: Ascomycota/growth & development*
Mixed herbs drugs: inhibitory effect on growth of the endogenous mycoflora and aflatoxin production

Razak MF, Aidoo KE, Candlish AG

Mycopathologia, 2009 May;167(5):273-86.
PMID: 18991016 DOI: 10.1007/s11046-008-9167-3

Twenty commercial mixed herbal drugs were examined for mycological profile. Aspergillus species were the predominant fungi found in the drugs. Other fungi harboured in the drugs with less frequency were Paecilomyces species, Eurotium species, Monascus species, Acremonium species, Penicillium species, Cladosporium species, Scopulariopsis species, Phialophora species and Fonseceae species. Fungal count was between 1.0 log(10) CFU and 2.4 log(10) CFU per gram of sample. When the drugs were incubated in 85% humidity at 25 degrees C, fungal colonies grew on only two of the drugs. The mixed herbal drugs were extracted with water and the extracts were used to grow Aspergillus parasiticus. All extracts reduced aflatoxin B(1) and aflatoxin G(1) production by 62-97%. All but two of the extracts reduced aflatoxin B(2) and aflatoxin G(2) production by 39-95%. It can be concluded that the commercial powdered mixed herbal drugs contained low number of endogenous fungi, and these drugs are inhibitory to the growth of its endogenous fungi and aflatoxins production by aflatoxigenic fungi.

Matched MeSH terms: Ascomycota/growth & development*
Fulltext The genome of newly classified Ochroconis mirabilis: Insights into fungal adaptation to different living conditions

Yew SM, Chan CL, Kuan CS, Toh YF, Ngeow YF, Na SL, et al.

BMC Genomics, 2016 Feb 03;17:91.
PMID: 26842951 DOI: 10.1186/s12864-016-2409-8

Ochroconis mirabilis, a recently introduced water-borne dematiaceous fungus, is occasionally isolated from human skin lesions and nails. We identified an isolate of O. mirabilis from a skin scraping with morphological and molecular studies. Its genome was then sequenced and analysed for genetic features related to classification and biological characteristics.

Matched MeSH terms: Ascomycota/growth & development
Fulltext Nematophagous fungi as a biological control agent for nematode parasites of small ruminants in Malaysia: a special emphasis on Duddingtonia flagrans

Chandrawathani P, Jamnah O, Waller PJ, Höglund J, Larsen M, Zahari WM

Vet Res, 2002 Nov-Dec;33(6):685-96.
PMID: 12498569

Approximately 2,800 fresh dung samples from animals, mainly ruminant livestock, were screened for the presence of nematophagous fungi in Malaysia. Arthrobotrys spp. was noted on numerous occasions, but only one isolate of Duddingtonia flagrans was made. For the purposes of producing sufficient quantities of this fungus for feeding trials in sheep, various, commonly available, cheap plant materials were tested as possible growth substrates. This showed that cereal grains (wheat, millet and rice) were the best media for fungal growth. Pen feeding trials were carried out using sheep, both naturally and experimentally infected with nematode parasites (predominantely Haemonchus contortus), to test the efficiency of D. flagrans when administered either in a grain supplement, or incorporated into a feed block. These showed that the fungus survived gut passage in sheep and that dose rates of approximately 1 x 10(6) D. flagrans spores / animal / day, reduced the percentage of infective larvae developing in faecal cultures by more than 90%. These results indicate that using D. flagrans as a biological control agent of nematode parasites, is a promising alternative to nematode parasite control of small ruminants in Malaysia, where anthelmintic resistance is now a major problem.

Matched MeSH terms: Ascomycota/growth & development
Fulltext Fatty Acid Synthase Beta Dehydratase in the Lipid Biosynthesis Pathway Is Required for Conidiogenesis, Pigmentation and Appressorium Formation in Magnaporthe oryzae S6

Sangappillai V, Nadarajah K

Int J Mol Sci, 2020 Sep 30;21(19).
PMID: 33007862 DOI: 10.3390/ijms21197224

Lipid biosynthesis produces glycerol, which is important in fueling turgor pressure necessary for germination and penetration of plant host by fungi. As the relationship between pathogenicity and the lipid biosynthetic pathway is not fully understood, we have elucidated the role of the fatty acid synthase beta subunit dehydratase (FAS1) gene in lipid biosynthesis. The FAS1 gene was silenced through homologous double crossover in Magnaporthe oryzae strain S6 to study the effect on lipid biosynthesis. The vegetative growth of Δfas1 mutants show the highest drop on oleic acid (between 10 and 50%), while the mycelial dry weight of mutants dropped significantly on all media. Conidiation of FAS1 mutants show a ~10- and ~5-fold reduction on oatmeal and Potato Dextrose Agar (PDA), respectively. Mutants formed mycelium that were mildly pigmented, indicating that the deletion of FAS1 may have affected melanin biosynthesis. Biochemical and gene expression studies concluded that the fatty acid degradation pathway might have been interrupted by FAS1 deletion. FAS1 mutants showed no enzyme activity on glucose or olive oil, suggesting that the mutants may lack functional peroxisomes and be defective in β-oxidation of fatty acids, hence explaining the reduced lipid deposits in the spores.

Matched MeSH terms: Ascomycota/growth & development
Fulltext Comparative chemical screening and genetic analysis reveal tentoxin as a new virulence factor in Cochliobolus miyabeanus, the causal agent of brown spot disease on rice

De Bruyne L, Van Poucke C, Di Mavungu DJ, Zainudin NA, Vanhaecke L, De Vleesschauwer D, et al.

Mol Plant Pathol, 2016 Aug;17(6):805-17.
PMID: 26456797 DOI: 10.1111/mpp.12329

Brown spot disease, caused by Cochliobolus miyabeanus, is currently considered to be one of the most important yield reducers of rice (Oryza sativa L.). Despite its agricultural importance, little is known about the virulence mechanisms deployed by the fungus. Therefore, we set out to identify novel virulence factors with a role in disease development. This article reports, for the first time, the production of tentoxin by C. miyabeanus as a virulence factor during brown spot disease and the identification of the non-ribosomal protein synthetase (NRPS) CmNps3, responsible for tentoxin biosynthesis. We compared the chemical compounds produced by C. miyabeanus strains differing in virulence ability using ultra-high-performance liquid chromatography (UHPLC) coupled to high-resolution Orbitrap mass spectrometry (HRMS). The production of tentoxin by a highly virulent strain was revealed by principal component analysis of the detected ions and confirmed by UHPLC coupled to tandem-quadrupole mass spectrometry (MS/MS). The corresponding NRPS was identified by in silico genome analysis and confirmed by gene deletion. Infection tests with wild-type and Cmnps3 mutants showed that tentoxin acts as a virulence factor and is correlated with chlorosis development during the second phase of infection. Although rice has previously been classified as a tentoxin-insensitive plant species, our data demonstrate that tentoxin production by C. miyabeanus affects symptom development.

Matched MeSH terms: Ascomycota/growth & development
Biological control of nematode parasites of small ruminants in Malaysia using the nematophagous fungus Duddingtonia flagrans

Chandrawathani P, Jamnah O, Waller PJ, Larsen M, Gillespie AT, Zahari WM

Vet Parasitol, 2003 Nov 14;117(3):173-83.
PMID: 14630426

Control of nematode parasites of small ruminants in a wet, tropical environment using the nematophagous fungus, Duddingtonia flagrans, was assessed in this study. Two methods of fungal delivery were tested, namely as a daily feed supplement, or incorporated into feed blocks. Initially, pen trials were conducted with individually penned groups of sheep and goats at dose rates of 125,000 spores and 250,000 spores/kg live weight per day. At the lower dose rate this reduction was between 80 and 90% compared with the pre-treatment levels. At the higher dose rate, there was virtually complete suppression (>99% reduction) of larval recovery. Trials using the fungal feed blocks, showed that when animals were individually penned, they consumed only small amounts of the block (particularly goats), hence little effect on larval recovery in faecal cultures was observed. Grouping animals according to species and dose rate induced satisfactory block consumption and subsequent high levels of larval reduction in faecal cultures. These larval reductions were mirrored by the presence of fungus in faecal cultures. This work was followed by a small paddock trial, whereby three groups of sheep were fed either a feed supplement without fungal spores, supplement with spores, or offered fungal blocks. The dose rate of spores in the latter two groups was 500,000 spores/kg live weight per day. Egg counts were significantly reduced in the two fungal groups, compared with the control group and the latter required two salvage anthelmintic treatments to prevent mortality due to haemonchosis. Pasture larval numbers on the two fungal group plots were also much lower than on the control plot.

Matched MeSH terms: Ascomycota/growth & development