Fusarium graminearum is an important fungal pathogen of cereal crops and produces mycotoxins, such as the trichothecenes nivalenol and deoxynivalenol. This species may be subdivided into a series of genetic lineages or phylogenetic species. We identified strains of F. graminearum from the Republic of Korea to lineage, tested their ability to produce nivalenol and deoxynivalenol, and determined the genetic composition and structure of the populations from which they were recovered. Based on amplified fragment length polymorphism (AFLP), PCR genotyping, and chemical analyses of trichothecenes, all 249 isolates from southern provinces belonged to lineage 6, with 241 having the nivalenol genotype and 8 having the deoxynivalenol genotype. In the eastern Korea province, we recovered 84 lineage 6 isolates with the nivalenol genotype and 23 lineage 7 isolates with the deoxynivalenol genotype. Among 333 lineage 6 isolates, 36% of the AFLP bands were polymorphic, and there were 270 multilocus haplotypes. Genetic identity among populations was high (>0.972), and genotype diversity was low (30 to 58%). To test the adaptation of lineage 6 to rice, conidial mixtures of strains from lineages 3, 6, and 7 were inoculated onto rice plants and then recovered from the rice grains produced. Strains representing lineages 6 and 7 were recovered from inoculated spikelets at similar frequencies that were much higher than those for the strain representing lineage 3. Abundant perithecia were produced on rice straw, and 247 single-ascospore isolates were recovered from 247 perithecia. Perithecia representing lineage 6 (87%) were the most common, followed by those representing lineage 7 (13%), with perithecia representing lineage 3 not detected. These results suggest that F. graminearum lineage 6 may have a host preference for rice and that it may be more fit in a rice agroecosystem than are the other lineages present in Korea.

Minoxidil, a pyrimidine derivative (2,4-diamino-6-piperidino-pyrimidine-3-oxide) is an adenosine triphosphate (ATP) sensitive potassium chennel (K ATP chennel) opener, and is the most commonly used drug for the treatment of androgenetic alopecia.1) Topical minoxidil shortens the telogen phase by induction of the entry of resting hair follicles into the anagen phase, prolongs anagen growth phase and increases the volume of hair follicles. Although the mechanism through which minoxidil promotes hair growth is still speculative, a number of in vitro studies using minoxidil have been described in various skin and hair follicle cell types including the stimulation of cell proliferation, and the induction of vascular endothelial growth factor 2,3) and prostaglandin synthesis.4) In addition, minoxidil has been shown to increase blood circulation around hair follicles 5,6) and to markedly elevate 17b-hydroxysteroid dehydrogenase activity, which accelerated the conversion of testosterone to weaker androgens. 7)Retinol significantly improves the scalp skin condition and promotes hair growth, in terms of the keratinization of skin and hair. 8) Retinol is ingested in precursor forms; animal sources contain retinyl esters whereas plants contain carotenoids. Tissue cells convert these organic precursor forms to retinol, and this to either retinal or retinoic acid. These two species exert profound effects on the growth, maturation, and differentiation of many cell types, both in vivo and in vitro.8) Retinoic acid, the active metabolite of vitamin A, has been reported to play an important role in the growth, differentiation and maintenance of hair follicles. 9) Moreover, cellular retinoic acid-binding proteins (CRBPs) are known to be important for the mediations of some of the effects of retinoids. These effects are mediated by two classes of nuclear retinoic acid receptors, termed retinoic acid receptor (RAR) and retinoid x receptor (RXR), and each of these classes is composed of subtypes designated alpha, beta, and gamma.Recently, we showed that minoxidil prolongs the anagen stage and that the enhanced hair growth may result from two mechanisms: (i) the activations of Erk and Akt signaling which enhance the survival of cultured DPCs, and (ii) an increase in the Bcl-2/Bax ratio which protects cells against cell death.10) The aim of the present study was to evaluate possible additive interaction between minoxidil and retinol on human hair growth and to investigate the mechanism of action of minoxidil plus retinol using cultured human DPCs and keratinocytes. MATERIALS AND METHODS MaterialsMinoxidil and retinol were purchased from Sigma (St Louis, MO, U.S.A.). Minoxidil was dissolved in 0.12 mM HCl and a 1.0 mM minoxidil stock solution was stored at Ϫ20°C. Retinol was dissolved in absolute ethanol and shielded from the light using aluminum foil until required. All inhibitors [U0126, an ERK kinase (MEK1 and 2)-inhibitor; LY 294002 (LY) and Wortmannin, selective PI3K inhibitor] were purchased from Calbiochem (San Diego, CA, U.S.A.)...

Twenty eight samples of rice, barley, millet, corn and Indian millet harvested in Korea in 1989 were subjected to assay for contamination of nivalenol (NIV), deoxynivalenol (DON) and T-2 toxin by using gas chromatography and gas chromatography-mass spectrometry. Seven samples were found to be positive for NIV and DON in the ranges of 189-624 micrograms/kg and 168-506 micrograms/kg, respectively. Of the contaminated samples, three samples, one barley, one Indian millet and one corn sample were contaminated simultaneously with both NIV and DON. T-2 toxin was not detected in any samples.