Fusarochromanone production by Fusarium isolates.

Sixty two Fusarium isolates representing nine species from many parts of the world were screened for fusarochromanone production. A simplified method for the detection of fusarochromanone in culture filtrates or grain cultures was used. Under UV irradiation (364 nm) the chloroform phase from fusarochromanone-positive culture extracts fluoresced a characteristic bright blue color. Results were confirmed by thin-layer-chromatography comparison with pure fusarochromanone standards. Detection was possible in cultures as young as 1 week old. Biosynthesis of fusarochromanone was rare in Fusarium spp. and was only detected in three isolates of Fusarium equiseti, namely R-4482 (barley [Federal Republic of Germany]), R-6137 (barley [Alaska]), and R-8508 (potato [Denmark]), among all the isolates tested from various geographic sources.     

Isolation and Partial Characterization of a Mycotoxin from Penicillium roqueforti

Extracts of pure cultures of Penicillium roqueforti isolated from toxic feed samples and of P. roqueforti NRRL 849 were lethal to rats by either intraperitoneal or oral administration. Purification studies guided by this test led to the isolation of a major toxin which showed intraperitoneal and oral median lethal dose values in weanling rats of 11 and 115 mg/kg, respectively. Partial characterization of the crystalline compound, C(17)H(20)O(6), by infrared, ultra violet, PMR, and mass spectroscopy, and by several chemical transformations indicated the presence of three C-methyl substituents plus one acetoxy, one aldehyde, and one alpha,beta-unsaturated ketone group. Two oxygen atoms are present either in epoxide or ether form.     

Incorporation of Chlorine-36 into Ochratoxin A

Incubation of Aspergillus ochraceus NRRL 3174 in a medium containing Na(36)Cl incorporated (36)Cl into ochratoxin A. The highest incorporation (0.75 and 0.70%, respectively) was obtained when the radioactive chloride was added to the medium by the 2nd or 3rd day of incubation.     

The relationship between total non-haem,ferritin and haemosiderin iron in larvae of Southern Hemisphere lampreys (Geotria australis andMordacia mordax)

Summary The major iron binding protein (IBP) of larvalM. mordax has an estimated molecular weight (354,000), subunit molecular weight (18,000) and pI (5.1) identical to those recorded previously for larvalG. australis. The IBP in larvalG. australis has also been shown to be relatively heat stable and to react immunologically with antihorse spleen ferritin. The weight of total non-haem iron in the whole body, and both the ferritin and haemosiderin iron components, increased with increasing body weight in larvalG. australis. While the concentration of ferritin iron remained similar throughout larval life, the concentration of total non-haem iron and haemosiderin iron increased rapidly in animals up to a body weight of 0.1–0.2 g, but thereafter rose only slowly throughout the rest of larval life. This implies that any iron in excess of the amount required for the maintenance of a constant ferritin concentration is converted into haemosiderin iron, and that once non-haem iron has reached a particular concentration (c. 500–600 g g^–1), the rate of iron accumulation is greatly reduced. While the larvae of bothG. australis andM. mordax had very high plasma iron levels (>19,000 g 100 ml^–1), the former had significantly greater concentrations of iron in the whole body (702vs. 267 g g^–1) and more particularly in the nephric fold (7382vs. 224 g g^–1). A greater reservoir of non-haem iron could facilitate the maintenance of the large amounts of haem and erythrocytic ferritin present in this species as a result of an exceptionally high haemoglobin concentration and red blood cell number. The greater concentration of non-haem iron in the intestine ofM. mordax than ofG. australis (1338vs. 824 g g^–1), when considered in conjunction with histological studies, indicates thatMordacia mordax eliminates a larger amount of iron during the extrusion of its intestinal columnar cells.Abbreviation IBP iron binding protein     

Attention deficit hyperactivity disorder: fine mapping supports linkage to 5p13, 6q12, 16p13, and 17p11

We completed fine mapping of nine positional candidate regions for attention-deficit/hyperactivity disorder (ADHD) in an extended population sample of 308 affected sibling pairs (ASPs), constituting the largest linkage sample of families with ADHD published to date. The candidate chromosomal regions were selected from all three published genomewide scans for ADHD, and fine mapping was done to comprehensively validate these positional candidate regions in our sample. Multipoint maximum LOD score (MLS) analysis yielded significant evidence of linkage on 6q12 (MLS 3.30; empiric P=.024) and 17p11 (MLS 3.63; empiric P=.015), as well as suggestive evidence on 5p13 (MLS 2.55; empiric P=.091). In conjunction with the previously reported significant linkage on the basis of fine mapping 16p13 in the same sample as this report, the analyses presented here indicate that four chromosomal regions--5p13, 6q12, 16p13, and 17p11--are likely to harbor susceptibility genes for ADHD. The refinement of linkage within each of these regions lays the foundation for subsequent investigations using association methods to detect risk genes of moderate effect size.     

Toxic spiroepoxy compounds from Fusaria and other hyphomycetes

Many hyphomyceteous fungi have been found to produce closely related toxic metabolites which form the class of compounds called scirpenes. The structures of those compounds are reviewed and current studies on their biological activity and possible implication in moldy corn poisoning are discussed.     

Molecular evolution of a multigene family in group A streptococci

The emm genes are members of a gene family in group A streptococci (GAS) that encode for antiphagocytic cell-surface proteins and/or immunoglobulin-binding proteins. Previously sequenced genes in this family have been named "emm," "fcrA," "enn," "arp," "protH," and "mrp"; herein they will be referred to as the "emm gene family." The genes in the emm family are located in a cluster occupying 3-6 kb between the genes mry and scpA on the chromosome of Streptococcus pyogenes. Most GAS strains contain one to three tandemly arranged copies of emm-family genes in the cluster, but the alleles within the cluster vary among different strains. Phylogenetic analysis of the conserved sequences at the 3' end of these genes differentiates all known members of this family into four evolutionarily distinct emm subfamilies. As a starting point to analyze how the different subfamilies are related evolutionarily, the structure of the emm chromosomal region was mapped in a number of diverse GAS strains by using subfamily-specific primers in the polymerase chain reaction. Nine distinct chromosomal patterns of the genes in the emm gene cluster were found. These nine chromosomal patterns support a model for the evolution of the emm gene family in which gene duplication followed by sequence divergence resulted in the generation of four major-gene subfamilies in this locus.