Carotenoid metabolism is induced in rice bran during very high temperature stress.

Background: Postharvest yellowing (PhY) causes yellowing in rice endosperm during conditions of high temperature and moisture. Rice bran was investigated as a model tissue for studying PhY and for determining the possibility of carotenoids as the source of the yellow color.

Results: A survey of different colored rice and wild (non-sativa) rice lines resulted in the identification of several purple bran lines having very low or no bran carotenoids.

Meiotic transmission of an in vitro-assembled autonomous maize minichromosome.

Autonomous chromosomes are generated in yeast (yeast artificial chromosomes) and human fibrosarcoma cells (human artificial chromosomes) by introducing purified DNA fragments that nucleate a kinetochore, replicate, and segregate to daughter cells. These autonomous minichromosomes are convenient for manipulating and delivering DNA segments containing multiple genes. In contrast, commercial production of transgenic crops relies on methods that integrate one or a few genes into host chromosomes; extensive screening to identify insertions with the desired expression level, copy number, structure, and genomic location; and long breeding programs to produce varieties that carry multiple transgenes.

Traits of Soybean-Infecting Phytophthora Populations from Illinois Agricultural Fields.

Phytophthora rot caused by Phytophthora sojae is a common and significant disease of soybean (Glycine max) in Illinois and throughout the Midwestern United States. The pathogenic characteristics of P. sojae populations in several Midwestern states have been reported recently, but pathogenicity and fungicide sensitivity traits of populations in Illinois were poorly understood.

Toxicity and antitumor activity of hexamethylmelamine and its N-demethylated metabolites in mice with transplantable tumors.

N-Demethylated metabolites of the antineoplastic agent hexamethylmelamine were synthesized, and their toxicities and antitumor activities were determined in vivo. Determinations of the lethal dose for 10% of the male C57BL X DBA/2 F1 (hereafter called BD2F1) mice showed hexamethylmelamine toxicity to be decreased by N-demethylation; the metabolites showed a direct relationship between potency (mmoles/kg/day) and number of methyl groups present. In BD2F1 mice bearing Sarcoma 180 or Lewis lung carcinoma, the antitumor activities of the methylmelamines decreased with a reduction in number of methyl groups, but were similar at equitoxic levels.

Effect of deoxyuridine coadministration on toxicity and antitumor activity of fluorouracil and floxuridine.

The addition of deoxyuridine (UDR) to fluorouracil (FU) or floxuridine (5-fluoro-2' deoxyuridine) (FUDR) produced a substantial increase in their toxicity in BDF1 mice. Antitumor assays using sarcoma 180 tumor-bearing mice showed a concomitant increase in tumor growth inhibition for the nucleoside-drug combination over identical doses of the single drug. However, no significant increase in antitumor activity with the combination treatment was demonstrated when equitoxic doses were given.