Penicillium aurantiogriseum Dierckx produces chaetoglobosin A toxic to embryonic chickens

Several strains of the genusPenicillium isolated from swabs from uranium miners working environment were screened for production of known mycotoxins; and embryotoxicity of chloroform extracts from the isolates was investigated in chick embryos.Penicillium aurantiogriseum was found to produce chaetoglobosin A. ED₅₀ of this mycotoxin for 2-, 3- and 4-day-old chick embryos was found 0.040 (0.031–0.052), 0.074 (0.051–0.107), and 0.180 (0.113–0.229) µg/embryo, respectively. The effect was purely embryolethal with no signs of teratogenicity recorded. This is the first report on the isolation of chaetoglobosin A from the genusPenicillium.     

Growth and mycotoxin production by <Emphasis Type="Italic">Chaetomium globosum</Emphasis>

Chaetomium globosum, the most common species within this genus, produces chaetoglobosins A and C when cultured on building material. Relatively low levels of these compounds have been shown to be lethal to various tissue culture cell lines. This study had two major objectives: (1) to determine the frequency at which Chaetomium species are isolated in water-damaged buildings and (2) to examine the production of chaetoglobosins A and C in isolates of C. globosum obtained from different buildings. Out of 794 water-damaged buildings, Chaetomium species were isolated in 49% of these structures. C. globosum ATCC 16021 was grown on four different media: oatmeal agar (OA), potato dextrose agar (PDA), corn meal agar (CMA), and malt extract agar (MEA). After 4 weeks, fungal growth was evaluated based on colony diameter and the quantity of spores produced on agar plates. In addition, production of chaetoglobosin A and C was monitored using high performance liquid chromatography. Colony diameter, spore production, and mycotoxin production by C. globosum were the highest on OA. Out of 30 C. globosum isolates cultured on OA for 4 weeks, 16 produced detectable amounts of chaetoglobosin A and every isolate produced chaetoglobosin C.     

A PKS gene, pks-1, is involved in chaetoglobosin biosynthesis, pigmentation and sporulation in Chaetomium globosum

Chaetomium globosum is one of the most common fungi in nature. It is best known for producing chaetoglobosins; however, the molecular basis of chaetoglobosin biosynthesis is poorly understood in this fungus. In this study, we utilized RNA interference (RNAi) to characterize a polyketide synthase gene, pks-1, in C. globosum that is involved in the production of chaetoglobosin A. When pks-1 was knocked down by RNAi, the production of chaetoglobosin A dramatically decreased. Knock-down mutants also displayed a pigment-deficient phenotype. These results suggest that the two polyketides, melanin and chaetoglobosin, are likely to share common biosynthetic steps. Most importantly, we found that pks-1 also plays a critical role in sporulation. The silenced mutants of pks-1 lost the ability to produce spores. We propose that polyketides may modulate cellular development via an unidentified action. We also suggest that C. globosum pks-1 is unique because of its triple role in melanin formation, chaetoglobosin biosynthesis and sporulation. This work may shed light on chaetoglobosin biosynthesis and indicates a relationship between secondary metabolism and fungal morphogenesis.     

Effects of Orally Administered Bovine Lactoferrin on the Faecal Enterobacteriaceae of SPF Mice Fed Milk

Several phytotoxic metabolites, including a novel compound chaetoglobosin O, were isolated from Cylindrocladium floridanum Sobers et Seymore. The structure of chaetoglobosin O, including its absolute configuration, was determined by a spectroscopic analysis and chemical correlation. Purified chaetoglobosins A, C, and O showed potent growth-inhibition activity against alfalfa seedlings.     

Chaetoglobosin Vb from endophytic Chaetomium globosum: absolute configuration of chaetoglobosins

One new cytochalasan alkaloid, chaetoglobosin V(b) (1), together with two structurally related known compounds, chaetoglobosin V (2) and chaetoglobosin G (3), was isolated from the ethyl acetate extract of a culture of the endophytic fungus Chaetomium globosum, associated with the leaves of Ginkgo biloba tree. The structures of the isolated compounds were elucidated by spectroscopic methods including 1D and 2D NMR and mass spectrometry. The absolute configuration of chaetoglobosin V(b) (1) was established by means of electronic circular dichroism (CD) spectroscopy, on the basis of the comparison between the CD spectrum of (+)-1 with that calculated with time-dependent density functional theory method for a simplified model. The correlation between compounds 1-3 was demonstrated by a biomimetic transformation of chaetoglobosin G (3) under mild conditions in chaetoglobosins V and V(b) (1 and 2). The isolated metabolites were tested against some phytopathogens.     

Antibacterial activity against drug-resistant microbial pathogens of cytochalasan alkaloids from the arthropod-associated fungus Chaetomium globosum TW1-1

By feeding 1-methyl-l-tryptophan (1-MT) into cultures of the arthropod-associated fungus Chaetomium globosum TW1-1, three novel cytochalasan alkaloids, termed as armochaetoglosins A–C (1–3), together with five known analogues, namely prochaetoglobosin I (4), chaetoglobosin T (5), chaetoglobosin C (6), armochaetoglobin Y (7), and chaetoglobosin V_b (8), were isolated and characterized. Their structures including absolute configurations were elucidated by means of NMR spectroscopy, single-crystal X-ray crystallography, and comparison of the experimental electronic circular dichroism (ECD) spectra. Structurally, compounds 1–3 represented the first examples of 1′-N-methyl-chaetoglobosins, which were possibly biosynthesized from the additive 1-MT rather than tryptophan. Additionally, compound 3 showed the highest antibacterial activity against K. pneumoniae and ESBL-E. coli with MIC values of 4.0 μg/mL and 16.0 μg/mL, respectively, wherein the inhibitory effect of 3 against K. pneumoniae was stronger than that of the clinically used antibiotic meropenem, with an MIC value of 8 μg/mL. Our findings may provide new chemical templates for the development of new antibacterial agents against drug-resistant microbial pathogens.     

Efficacy assessment of antifungal metabolites from Chaetomium globosum No.05, a new biocontrol agent,against Setosphaeria turcica

Northern corn leaf blight (NCLB), an important and potentially destructive corn foliar disease, is caused by Setosphaeria turcica. The intent of this study was to evaluate antifungal metabolites from Chaetomium globosum (Cg) strain No.05 to suppress NCLB in maize. This strain significantly suppressed mycelial growth of numerous phytopathogenic fungi especially S. turcica on potato dextrose agar medium. The secondary metabolites of the strain inhibited mycelial growth and conidial germination of S. turcica. When co-inoculated at three droplets (5 μL/droplet) of conidial suspension (5 × 10⁴ conidia/mL) on each 8-cm-long detached leaf, 20% culture filtrates completely suppressed disease incidence of northern corn leaf blight. The application of the culture filtrates at 2 h post-inoculation (hpi) of S. turcica in greenhouse studies showed a 81.9% inhibition of NCLB on the seedlings, while culture filtrates applied before pathogen inoculation showed even higher rates of disease reduction. The application of the culture filtrates had no observed effects on the treated maize leaves or seedlings. Two active compounds, isolated from the extracts, were identified as chaetoglobosin A and chaetoglobosin C based on the spectroscopic analysis. Both in vitro and in planta bioassay experiments showed that chaetoglobosin A displayed potent biocontrol efficiency against S. turcica. To the best of our knowledge, this is the first report of the evaluation of the inhibitory effects of C. globosum and chaetoglobosin A against S. turcica both in vitro and on detached maize leaves.     

Penicillium siamensis sp. nov., from Thailand soil

Fungal flora of 20 samples of lentil seeds collected from Assiut governorate, Egypt, were studied. Seventeen genera and 13 species were isolated on glucose- (15 genera and 27 species), cellulose-(15 genera and 25 species)Czapek's agar media at 28 °C. The most common species were as follows: on glucose-Czapek's agar, Aspergillus fumigatus, A. niger, A. flavus, A. terreus, Penicillium notatum and Rhizopus oryzae and on cellulose agar, A. fumigatus, A. niger, A. flavus and P. notatum. Thin layer chromatographic (TLC) analysis and a biological test (Artemia salina) indicated the presence and the toxicity of aflatoxin in the extract of one sample (aflatoxins B₁, B₂, G₁ and G₂, at 20 mg/kg, total). This is the first report of the natural occurrence of aflatoxins in lentils.     

Production of vineomycin A1 and chaetoglobosin A by <Emphasis Type="Italic">Streptomyces</Emphasis> sp. PAL114

An actinobacteria strain PAL114, isolated from a Saharan soil in Algeria, produces bioactive compounds. Morphological and chemical studies indicated that this strain belongs to the genus Streptomyces. Analysis of the 16S rRNA gene sequence showed a similarity level of 99.8 % with S. griseoflavus LMG 19344^T, the most closely related species. Two bioactive compounds, named P44 and P40, were extracted by dichloromethane from the cell-free supernatant broth and were purified by HPLC. Minimum inhibitory concentrations (MIC) of the compounds were determined against pathogenic and toxigenic microorganisms, most of which are multiresistant to antibiotics. The P40 fraction showed a strong activity especially against Candida albicans, Bacillus subtilis, and Staphylococcus aureus and has lower MIC values than those of P44 against most microorganisms tested. Chemical structures of compounds were determined based on spectroscopic and spectrometric analyses (UV-visible, mass, ¹H, and ¹³C NMR spectra). The compounds P44 and P40 were identified as vineomycin A1 and chaetoglobosin A, respectively. Vineomycin A1 is known to be produced by some Streptomyces species. However, chaetoglobosin A is known to be produced only by fungi belonging to the genera Chaetomium, Penicillium, and Calonectria. This is the first time that chaetoglobosin A, known for its antimicrobial, anticancer, and cytotoxic effects, is reported in prokaryotes.     

Biological Evaluation of Secondary Metabolites from the Root of Machilus obovatifolia

Bioassay‐guided fractionation of the root of Machilus obovatifolia led to the isolation of four new lignans, epihenricine B ( 1 ), threo‐(7′R,8′R) and threo‐(7′S,8′S)‐methylmachilusol D ( 2 and 3 ), and isofragransol A ( 4 ), along with 23 known compounds. The compounds were obtained as isomeric mixtures (i.e., 2 / 3 and 4 / 20 , resp.). The structures were elucidated by spectral analyses. Among the isolates, 1 , licarin A ( 12 ), guaiacin ( 14 ), (±)‐syringaresinol ( 21 ), and (?)‐epicatechin ( 23 ) showed ABTS (=2,2′‐azinobis(3‐ethylbenzothiazoline‐6‐sulfonic acid) cation radical‐scavenging activity, with SC₅₀ values of 11.7±0.5, 12.3±1.1, 11.0±0.1, 10.6±0.3, and 9.5±0.2 μM in 20 min, respectively. In addition, kachirachirol B ( 17 ) showed cytotoxicity against the NCI‐H460 cell line with an IC₅₀ value of 3.1 μg/ml.     

Preventive effect of 20(S)-ginsenoside Rg3 against lipopolysaccharide-induced hepatic and renal injury in rats

The preventive effect of 20(S)-ginsenoside Rg₃ (20(S)-Rg₃) on lipopolysaccharide (LPS)-induced oxidative tissue injury in rats was investigated in this study. The elevated serum nitrite/nitrate, glutamic oxaloacetic transaminase, glutamic pyruvic transaminase and creatinine levels in LPS-treated control rats were significantly decreased following 15 consecutive days of 20(S)-Rg₃ administration. In addition, thiobarbituric acid-reactive substance levels in the serum, liver and kidney were dose-dependently lower in 20(S)-Rg₃-treated groups than in the LPS-treated control group. The nuclear factor-κB (NF-κB), cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS) and heme oxygenase-1 (HO-1) protein expressions in the liver and kidney were significantly increased by LPS treatment. However, the 20(S)-Rg₃ administrations significantly decreased these protein expressions except for HO-1 in the liver. On the other hand, in the kidney, oral administration of 20(S)-Rg₃ showed a tendency to reduce NF-κB and iNOS protein expressions and also significantly reduced the elevated COX-2 and HO-1 protein expressions at a dose of 10 mg/kg body weight/day. All these results suggest the preventive effect of 20(S)-Rg₃ against LPS-induced acute oxidative damage in the liver and kidney and the preventive effect of 20(S)-Rg₃ administration against LPS toxicity was thought to be more predominant in the liver than kidney.     

Occurrence of Toxic Hexadepsipeptides in Preharvest Maize Ear Rot Infected by Fusarium poae in Poland

Twenty‐seven preharvest maize ears affected by Fusarium poae rot (disease score 36–100%) were selected in 1998 and 1999 in Poland and examined for the occurrence of toxic hexadepsipeptides: beauvericin (BEA), enniatin A, enniatin B and enniatin B₁. The identification of F. poae was confirmed by sequence analysis of variable internal transcribed spacer regions and compared with NCBI gene bank DNA sequences. Chemical analyses were performed by HPLC‐MS. In 27 ears infected by F. poae were detected: BEA (trace to 46 μg/g) in 18 samples, enniatin A (trace to 37 μg/g) in nine samples, enniatin B (trace to 47 μg/g) in 15 samples and enniatin B₁ (trace to 25 μg/g) in 12 samples. When 20 strains of F. poae isolated from these samples were cultured on rice, all produced BEA (1.9–75 μg/g), three enniatin A (1.8–2 μg/g), 12 enniatin B (1.1–5.1 μg/g) and eight enniatin B₁ (1.2–5.2 μg/g). Occurrence and quantification of enniatin A, enniatin B and enniatin B₁ and their co‐occurrence with BEA in maize kernels is reported for the first time.     

银杏内生菌Chaetomium globosum ZY-22次生代谢产物分离鉴定

采用柱层析方法从银杏叶内生真菌Chaetomium globosum ZY-22的培养菌丝体提取物中分离得到脑苷脂B(1)、脑苷脂C(2)、尿囊素(3)、9(11)-去氢麦角甾醇过氧化物(4)以及4,6,8,22-四烯-3-酮-麦角甾烷(5)和球毛壳甲素(6)共6个次生代谢物;经波谱分析确定了6个化合物的结构,其中脑苷脂B、脑苷脂C和尿囊素是首次从内生真菌中得到;海虾致死试验结果显示,化合物1～6在10 μg/mL浓度下对丰年虾的致死率分别为1.6%、4.2%、7.4%、16.9%、12.8%、83.6%、表明球毛壳甲素对海虾表现出很强的毒性作用.     

Growth of spoilage mould and aflatoxin B1 production in naturally contaminated or artificially inoculated maize as influenced by moisture content under ambient tropical condition

Maize (cv. TSZB) samples were re-moistened to different moisture contents (m.c.s) of 13, 15, 17, 20, 25, 30 or 35% and stored with the natural microflora or sterilized before artificial inoculation with either single or mixed moulds (Aspergillus flavus, A. niger, Penicilium purpurogenum and Fusarium moniliforme) and evaluated for initiation time for moulding, fungal populations and aflatoxin B₁ production. Whereas the fungal populations of naturally contaminated maize of 13% m.c. decreased significantly with storage, 17 and 20% m.c. maize increased with the latter showing maximum of about log₁₀ 7 colony forming units (cfu g⁻¹). Of the samples (13, 15, 17 or 20% m.c. maize), only those of ≥20% m.c. showed hazardous levels (>20 ppb) of aflatoxin B₁ production. The 20% m.c. sample also showed a significant positive correlation (r = 0.92) between m.c. and fungal load but those of lower m.c.s exhibited poor correlations, probably reflecting the absence of changes in the m.c.s of the 13, 15 and 17% m.c. maize. Aflatoxin B₁ content of 25% m.c. maize increased with increase in inoculum concentration of A. flavus. Mixed mould inoculation of maize samples resulted in a reduction in aflatoxin concentration with co-cultures of A. flavus and P. purpurogenum showing the lowest production, while that inoculated with A. flavus alone (control) exhibiting the maximum production. Initiation time for moulding was most rapid in ≥20% m.c. maize irrespective of inoculum type, with A. flavus being the most invasive in singly inoculated samples. However, A flavus was most competitive in 20–30% m.c. maize inoculated with mixed moulds, while F. moniliformewas most competitive in the 35% m.c. maize.     

Crossability of Brassica tournefortii and B. rapa, and morphology and cytology of their F1 hybrids

The crossability between Brassica tournefortii (TT, 2n = 20) and Brassica rapa (AA, 2n = 20) and the cytomorphology of their F₁ hybrids were studied. Hybrids between these two species were obtained only when B. tournefortii was involved as a female parent. The hybrid plants were intermediate for most of the morphological attributes and were found to be free from white rust under field conditions. The F₁ plants showed poor pollen fertility, although occasional seed set was achieved from open pollination. Self-pollination or backcrosses did not yield any seeds in these plants. The occurrence of chromosome association ranging from bivalents (0–7), trivalents (0–2) to a rare quadrivalent (0–1) in the dihaploid hybrids indicates pairing between the T and A genomes. The homoeologous pairing coupled with seed set in the F₁ plants offer an opportunity for interspecific gene transfers from B. tournefortii to B. rapa and vice-versa through interspecific hybridization. Received: 3 July 2000 / Accepted: 22 September 2000     

Primary genome scan for complex body shape‐related traits in the common carp Cyprinus carpio

To identify quantitative trait loci (QTL) that affect body shape in common carp Cyprinus carpio, a linkage map, 2159·23 cM long, was constructed with a total of 307 markers covering 51 linkage groups (LG). The map included 167 new single nucleotide polymorphism (SNP) markers derived from expressed sequence tags (EST) together with 140 microsatellite markers reported earlier. A primary genome scan was conducted for QTL for standard length (L_S), head length (L_H), body height (H_B), body width (W_B) and tail length (L_TAIL) in an F1 line containing 92 offspring. A total of 15 suggestive QTL on six LGs were found to associate with L_S, L_H, H_B, W_B and L_TAIL which explained 10·7–17·4% of the variance. Five significant QTL were detected for body‐shape related traits and located for LGs (lg1, 12 and 20). These QTL included: one associated with L_S (21·1% variance explained), three for H_B (almost 20% variance explained) and one for W_B (20·7% variance explained).     

Antimycobacterial Butanolides from the Root of Lindera akoensis

Three racemic butanolides, majorenolide ( 1 ), majorynolide ( 2 ), and majoranolide ( 3 ), with 18 known compounds, including ten butanolides, i.e., litsenolide A₂ ( 4 ), litsenolide B₂ ( 5 ), litsenolide C₁ ( 6 ), litsenolide C₂ ( 7 ), hamabiwalactone A ( 8 ), hamabiwalactone B ( 9 ), litseakolide A ( 10 ), litseakolide B ( 11 ), isoobtusilactone ( 12 ), and obtusilactone ( 13 ); one lignan, i.e., (±)‐syringaresinol ( 14 ), two flavans, i.e., (+)‐catechin ( 15 ), and (?)‐epicatechin ( 16 ), one coumarin, i.e., scopoletin ( 17 ), and four steroids, i.e., a mixture of β‐sitosterol ( 18 ) and stigmasterol ( 19 ), and a mixture of β‐sitosteryl‐3‐O‐β‐D ‐glucoside ( 20 ) and stigmasteryl‐3‐O‐β‐D ‐glucoside ( 21 ) were isolated from the root of Lindera akoensis. The structures of the isolates were elucidated by in‐depth spectroscopic analysis. Compounds 1 – 3 were previously assigned a δ‐lactone structure, which was then revised to a γ‐lactone structure, based on 1D‐NMR data. The cigar‐HMBC technique was used to confirm the accuracy of the γ‐lactone structure, and the zero [α] value of compounds 1 – 3 suggested that they were considerably racemized. Nine butanolides 1 – 3, 4 – 8 , and 10 showed antimycobacterial activities against M. tuberculosis H₃₇Rv, with MIC values of 15–50 μg/ml.     

Action of a pure xyloglucan endo-transglycosylase (formerly called xyloglucan-specific endo-(1-4)-β-d-glucanase) from the cotyledons of germinated nasturtium seeds

The action on tamarind seed xyloglucan of the pure, xyloglucan-specific endo-(1→4)-β-D-glucanase from nasturtium (Tropaeolum majus L.) cotyledons has been compared with that of a pure endo-(1→4)-β-D-glucanase (‘cellulase’) of fungal origin. The fungal enzyme hydrolysed the polysaccharide almost completely to a mixture of the four xyloglucan oligosaccharides: Exhaustive digestion with the nasturtium enzyme gave the same four oligosaccharides plus large amounts of higher oligosaccharides and higher-polymeric material. Five of the product oligosaccharides (D,E,F,G,H) were purified and shown to be dimers of oligosaccharides A to C. D (glc₈xyl₆) had the structure A→A, H (glc₈xyl₆gal₄) was C→C, whereas E (glc₈xyl₆gal), F (glc₈xyl₆gal₂) and G (glc₈xyl₆gal₃) were mixtures of structural isomers with the appropriate composition. For example, F contained B₂→B₂ (30%), A→C (30%), C→A (20%), B₂B₁ (15%) and others (about 5%). At moderate concentration (about 3 mM) oligosaccharides D to H were not further hydrolysed by the nasturtium enzyme, but underwent transglycosylation to give oligosaccharides from the group A, B, C, plus higher oligomeric structures. At lower substrate concentrations, hydrolysis was observed. Similarly, tamarind seed xyloglucan was hydrolysed to a greater extent at lower concentrations. It is concluded that the xyloglucan-specific nasturtium-seed endo-(1→4)-β-D-glucanase has a powerful xyloglucan-xyloglucan endo-transglycosylase activity in addition to its known xyloglucan-specific hydrolytic action. It would be more appropriately classified as a xyloglucan endo-transglycosylase. The action and specificity of the nasturtium enzyme are discussed in the context of xyloglucan metabolism in the cell walls of seeds and in other plant tissues.