First Report of Cobweb Disease Caused by Cladobotryum mycophilum on the Edible Mushroom Pleurotus eryngii in Korea.

Pleurotus eryngii is one of the most commercially important mushrooms in Korea. In May 2009, unusual symptoms were observed in P. eryngii grown in mushroom farms in Changnyeong and Hapcheon, in Gyeong-nam Province, Korea. One of the main symptoms was cobweb-like growth of fungal mycelia over the mushroom surface. Colonies on the surface rapidly overwhelmed the mushrooms, which turned pale brown or yellow. Mushrooms eventually turned dark brown and became rotten. Colonies of the isolates on potato dextrose agar (PDA) were yellowish, and a reddish or orange color was evident in the agar. The colonies grew 20 to 30 mm per day on PDA. Large spores with a single septum were produced on vertically branched conidiophores bearing two to four, mostly three to four, sporogenous cells, ranging from 17.2 to 20.5 µm long and 8.0 to 10.2 µm thick. The shape of the conidia was ellipsoid and obovoid. These morphological characteristics are consistent with descriptions of Cladobotryum mycophilum, a causal agent of cobweb disease in Agaricus bisporus (1,4). To identify the isolated fungal pathogen, the ITS region was amplified with ITS1 and ITS4 primers and sequenced. The sequence data from the isolate was deposited in GenBank (Accession No. JF693809). A BLAST search showed that the isolated strain belonged to a species of Cladobotryum. The highest similarity (99.5%) was to the ITS sequence of C. mycophilum (teleomorph Hypomyces odoratus) (GenBank Accession Nos. JF505112 and Y17096) (3,4). The strain that was tested for pathogenicity was grown on PDA at 25°C for 72 h. The inoculum was prepared by flooding the agar surface with 10 ml of sterilized double distilled water and scraping it with a spatula. The resulting spore suspension was filtered through three layers of cheesecloth. Conidial concentration was adjusted with a hemacytometer to 1 × 106 conidia ml-1. A conidia suspension was inoculated onto each of several stages of mushroom cultivation with a pipette. The control was spotted with double distilled water. In the case of infection during the inoculation and spawn running stages, the fungal mycelia colonized the media and hampered development of the mycelium of P. eryngii. In the regeneration and primordia formation stages of the host, the mycelium of the pathogen covered the surface of the plastic bottle containing the substrates and developed many spores. In the growing and harvesting stages, the surface of mushroom was overwhelmed by the mycelium of the fungal pathogen and turned pale or dark brown, accompanied by cracking of the stipe surface and finally rotting with a foul odor. These symptoms were similar to the observation from natural infection. The symptoms of the cobweb-like disease in A. bisporus (1,2) were observed within 5 to 7 days of inoculation with conidia suspensions of C. mycophilum. Fungi isolated from inoculated mushrooms were shown to be identical, based on phenotypic characteristic, to the inoculated strain used in these pathogenicity tests. No symptoms were observed on controls. To our knowledge, this is the first report on the occurrence of C. mycophilum on the edible mushroom P. eryngii in Korea. Based on the pathogenicity test results, the pathogen could attack P. eryngii in any cultivation stage, making it a potentially serious fungal pathogen in P. eryngii. References: (1) C. G. Back et al. J. Gen. Plant Pathol. 76:232, 2010. (2) R. H. Gaze. Mushroom J. 546:23, 1995. (3) F. J. Gea et al. Plant Dis. 95:1030, 2011. (4) H. M. Grogan and R. H. Gaze. Mycol. Res. 104:357, 2000.

Phylogenetic analysis of protozoa in the rumen contents of cow based on the 18S rDNA sequences.

AIMS: To examine the diversity of protozoa in the rumen contents of cow. METHODS AND RESULTS: Protozoa that inhabit the rumen were detected by PCR using protozoan-specific primers. Libraries of protozoan rDNA sequences were constructed from rumen fluid, solid tissues and epithelium. Twenty-three clones isolated from rumen fluid fell into two genera identified as Entodinium (69.6% of clones) and Epidinium (31.4% of clones). Of the clones isolated from rumen fluid, a moderate number were unidentifiable (30.4%). CONCLUSIONS: The predominant protozoan genus identified in the whole rumen belonged to the Entodinium group (81.1%). Protozoa were not detected in the rumen epithelium. SIGNIFICANCE AND IMPACT OF THE STUDY: These findings suggest that rumen fluid and solid tissues contain different protozoan populations that may play specific roles in rumen function. Quantitative PCR techniques and a more specific set of phylogenetic probes that distinguish between protozoan species are needed to determine the significance of newly identified groups and to determine the distribution of identified protozoan clusters in rumen microbial communities.

Biosorption of heavy metals using whole mold mycelia and parts thereof.

Biosorption of heavy metals was carried out using whole mycelia and selected components of Aspergillus niger, Rhizopus oryzae and Mucor rouxii. Binding of copper, cadmium, nickel and zinc was considerably improved by treating the cell wall fraction with 4 M NaOH at 121 degrees C. Chitosan contributed most to the biosorptive capacity. 0.96 mmol copper was bound by 1 g of the treated mycelium of M. rouxii DSM 1191.

Enhancement of recombinant glucoamylase expression by introducing yeast GAL7 mRNA termination sequence.

Glucoamylase gene (STA1) of Saccharomyces diastaticus was expressed in recombinant Saccharomyces cerevisiae systems. The yeast, GAL7 mRNA termination sequence, was introduced in the 3' noncoding region of the STA1 structural gene which was under the control of the SUC2 promoter and STA1 secretion signal sequence. This plasmid was named YEpSSG7 and was introduced into yeast S. cerevisiae MMY2 to construct recombinant S. cerevisiae MMY2SSG7. The GAL7 mRNA termination sequence enhanced the glucoamylase expression level by 3-5 times depending on the culture conditions compared to the result from the strain S. cerevisiae MMY2SUCSTA which did not contain the GAL7 mRNA termination sequence. Such an enhancement was not due to plasmid stability or plasmid copy number effects. Such an enhancement was primarily due to the fact that GAL7 mRNA termination sequence stabilized the STA1 mRNA 3' end.

Computer-assisted evaluation of ultrasonic fetal weight prediction using multiple regression equations with and without the fetal femur length.

Ultrasonic fetal femur length (FL) measurement provides an accurate fetal length. Combined with cross-sectional dimensions such as the biparietal diameter (BPD) and abdominal circumference (AC), FL provides a three-dimensional profile of the fetus. The usefulness of incorporating FL measurements into weight-predicting regression equations containing the BPD and AC was assessed. Multiple regression equations containing these three parameters as a function of log10 birthweight were constructed from data obtained from 125 patients within 48 hours of delivery. The mean errors in fetal weight prediction derived from five of these equations were assessed in another 92 patients. The coefficients of multiple correlation were marginally better in those equations that contained FL. The mean differences were also slightly lower with these equations compared with those that did not contain FL. However, the mean differences derived from all the equations were not significantly different from each other (P greater than 0.05). Therefore, despite theoretical considerations, the results from this study do not justify the routine clinical use of these new equations containing FL to estimate intrauterine fetal weight, in replacement of existing charts based on BPD and AC.

Abdominal circumference vs abdominal area--which is better?

The efficacies of ultrasonic abdominal circumference (AC) and abdominal area (AA) measurements in the evaluation of intrauterine fetal growth were compared. The intraobserver random and technical errors were found to be significantly higher with AA measurements. The correlation with intrauterine fetal weight was observed to be better with AC as compared with AA measurements, the fetal weights being expressed as either linear regressions or multiple regressions involving the two parameters. Between 32 and 38 weeks, a single AC measurement detects 74 per cent of small-for-date fetuses, while a single AA measurement detects only 58 per cent of such fetuses. The false-positive rates were similar for the two parameters. It is concluded that AA measurements are no more useful than AC measurements in the routine assessment of intrauterine fetal growth.