Changes in protein phosphorylation during the cell cycle of Chinese hamster ovary cells

The phosphorylation patterns of proteins were examined during the cell cycle of Chinese hamster ovary cells. This was accomplished by labeling synchronized cells at various times with [32P]orthophosphate and separating the proteins by both isoelectric focusing and nonequilibrium pH gradient two-dimensional gel electrophoresis. The most dramatic changes occurred during late G2/M when approximately eight proteins (including vimentin, lamin B, and histones 1 and 3) showed increased phosphorylation. Ten other proteins appeared to be uniquely phosphorylated during late G2/M. Of these 10 proteins, seven were no longer phosphorylated shortly after mitosis. There is also at least one protein which showed a relative decrease in phosphorylation during late G2/M.     

Genetics and Mechanism of Resistance to Meloidogyne arenaria in Peanut Germplasm

Segregation of resistance to Meloidogyne arenaria in six BC₅F₂ peanut breeding populations was examined in greenhouse tests. Chi-square analysis indicated that segregation of resistance was consistent with resistance being conditioned by a single gene in three breeding populations (TP259-3, TP262-3, and TP271-2), whereas two resistance genes may be present in the breeding populations TP259-2, TP263-2, and TP268-3. Nematode development in clonally propagated lines of resistant individuals of TP262-3 and TP263-2 was compared to that of the susceptible cultivar Florunner. Juvenile nematodes readily penetrated roots of all peanut genotypes, but rate of development was slower (P = 0.05) in the resistant genotypes than in Florunner. Host cell necrosis indicative of a hypersensitive response was not consistently observed in resistant genotypes of either population. Three RFLP loci linked to resistance at distances of 4.2 to 11.0 centiMorgans were identified. Resistant and susceptible alleles for RFLP loci R2430E and R2545E were quite distinct and are useful for identifying individuals homozygous for resistance in segregating populations.     

Restriction fragment length polymorphism (RFLP) analysis of bovine nuclear protein genes

Summary We have recently cloned both the bovine protamine (Krawetz et al. 1987, DNA 6: 47–57) and high mobility group (HMG-1) cDNAs (Pentecost and Dixon 1984, Bioscience Reports 4: 49–57). They have been used as probes for Restriction Fragment Length Polymorphism analysis of male-female pairs of different species and breeds, within the genus Bos. Utilizing this approach we have studied inheritance, chromosomal location and gene copy number of the bovine protamine and HMG-1 genes. This revealed that these nuclear protein genes are highly conserved suggesting that selective pressure has maintained their gene structures during evolution. A polymorphic Taq 1 restriction fragment was identified that was shown to be a heritable marker. These genes are not sex-linked and are present in a single copy for protamine and at least two copies for the HMG-1.     

Toxicity of polycyclic aromatic hydrocarbons. V. Protective effect of beta-naphthoflavone against hepatotoxicity induced by diphenaldehyde in rats

Male Sprague-Dawley rats were treated ip with beta-naphthoflavone (40 mg/kg/day) in corn oil or in DMSO for three days. Diphenaldehyde (90 mg/kg in DMSO) was injected ip 24 hr after pretreatment. The increase in the levels of aspartate aminotransferase, alanine aminotransferase, sorbitol dehydrogenase, gamma glutamyl transpeptidase, and lactate dehydrogenase was significantly lower in rats pretreated with BNF. This suggests that the BNF-induced P-450 isozyme systems have a protective effect against the acute hepatotoxicity of diphenaldehyde.     

Seasonal changes in density and tissue distribution of Onchocerca cervicalis microfilariae in ponies and related changes in Culicoides variipennis populations in Louisiana

Seasonal changes in density and spatial distribution of Onchocerca cervicalis microfilariae were studied in ventral-midline skin of 15 infected pony mares in southern Louisiana. Triple running mean analysis of data over a 13-mo period indicated that a distinct pattern exists in total microfilariae population density and in microfilariae occurrence in different levels of the dermis. Microfilariae density reaches peak levels in the spring followed by a 58% decrease in the summer, a 19% increase in the fall, and a decrease to the lowest numbers in the winter. Microfilariae were found in all levels of the skin during the spring, summer, and fall but were not found in the superficial layers of the dermis during the winter months. The population density of Culicoides variipennis, a demonstrated vector of O. cervicalis, appeared to have seasonal fluctuations similar to the changes in microfilarial density. Harmonic wave analysis of microfilariae density data in individual ponies showed that all individuals did not follow the population trend.     

Toxicity of polycyclic aromatic hydrocarbons. VI. Effects of 1-nitropyrene on serum enzyme levels in rats, and protection against it by beta-naphthoflavone and dimethyl sulfoxide

Male Sprague-Dawley rats were pretreated i.p. with corn oil or DMSO (1.5 ml/kg/day), or with beta-naphthoflavone (BNF, 40 mg/kg/day) in corn oil or DMSO for 3 days. 1-Nitropyrene (1-NP, 150 mg/kg) in DMSO was injected i.p. 24 hr after pretreatment. A significant increase in the levels of several serum enzymes was seen in rats pretreated with corn oil alone 24 hr after 1-NP injection. The increase in enzyme activities was significantly reduced by a 3-day pretreatment with DMSO or BNF.     

A comparison of the rates of ozonation of biological antioxidants and oleate and linoleate esters

The rates of reaction with ozone of some biological antioxidants and simple polyunsaturated fatty acids (PUFA) have been measured in water or in aqueous micellar solutions. At pH 7.0 the rate constants are ca. 10(6) M-1 sec-1 for urate, alpha-tocopherol, and PUFA, and 6 X 10(7) M-1 sec-1 for ascorbate. When ozone-containing air is breathed, ascorbate in the lung may undergo direct ozonation. However, alpha-tocopherol is probably spared direct reaction with ozone because it doesn't effectively compete with PUFA in pulmonary membranes; rather, tocopherol is used to scavenge radicals produced from the ozone-PUFA reaction.