Enzymatic changes in lung tissue of asbestotic guinea pigs.

The changes in the activities of some mitochondrial and soluble enzymes in the lungs of guinea pig, caused by three varieties of asbestos dust 120 days after intratracheal injection, were studied. Marked increase was observed in mitochondrial cytochrome oxidase, diaphorase and malic dehydrogenase. Among the soluble enzymes, lactic dehydrogenase showed the maximum variation.     

Suppression of auxin stimulated growth of barley coleoptile sections by endosulfan

Endosulfan, a cyclic sulphurous acid ester commonly used as a broad spectrum insecticide, suppressed the elongation of barley coleoptiles. Indoleacetic acid at optimum concentration overcame the inhibition of growth of coleoptiles treated with 10 ppm endosulfan. However, perfusion of the coleoptile sections with endosulfan and subsequent treatment with indoleacetic acid could not stimulate cell elongation to the extent observed in the control     

Selection of endosulfan-tolerant gram cell line

Three alternate exposures of Cicer arietinum (gram) root callus to lethal (1 ppm) endosulfan-containing selective medium (SM) and non-selective medium (NSM) yielded a tolerant cell line (1 ESR). Such an induced resistance was retained during subculture on NSM for 15 generations tested so far. Higher soluble proteins and peroxidase activity were found in 1 ESR compared to mother tissue.     

A cost-effective plasmid purification protocol suitable for fluorescent automated DNA sequencing

A cost-effective, reliable, and reproducible method has been developed to produce good-quality, double-stranded plasmid DNA for automated sequence analysis. The method incorporates modifications to a previously described plasmid-purification protocol used in manual sequencing. The quality of the DNA produced from the present protocol is suitable for automated fluorescent sequencing. Using a dye-terminator sequencing protocol, most runs using plasmid DNA prepared using this protocol produced over 700 bases with greater than 99% base-calling accuracy.     

The ataxia telangiectasia clastogenic factor is a low molecular weight peptide

Summary The clastogenic factor in the plasma of ataxia telangiectasia (AT) patients and in conditioned medium from AT skin fibroblast cultures is a peptide with a molecular weight in the range of 500 to 1000. No clastogenic activity could be demonstrated in extracts of cultured AT fibroblasts.     

Concentrations of circulating hormones normalized to pulses of a prostaglandin F2α metabolite during spontaneous luteolysis in mares

The temporal relationships between a pulse of 13,14-dihydro-15-keto-PGF_2α (PGFM) and the concentrations of circulating hormones during the luteolytic period were studied for 11 pulses in 11 mares (Equus caballus) using samples collected hourly. Mean PGFM pulses encompassed 4 h before to 4 h after the peak, and hormone data were normalized to the PGFM peak (Hour 0). Concentration of progesterone decreased (P < 0.05) between Hours –4 and –3 and continued to decrease linearly throughout the PGFM pulse. The concentrations of cortisol and prolactin increased (P < 0.004) during Hours –4 to 0 and decreased (P < 0.002) during Hours 0 to 4. Estradiol concentration increased (P < 0.02) during Hours –4 to 0 but did not change significantly after Hour 0. Concentrations of follicle-stimulating hormone and luteinizing hormone did not change significantly during the PGFM pulse, and the oxytocin results were equivocal. Percentage of corpus luteum area with color-Doppler signals of blood flow did not change significantly between Hours –4 and 0 and first began to decrease (P < 0.004) between Hours 0 and 2. Results demonstrated that concentrations of progesterone decreased linearly during a PGFM pulse, and cortisol, prolactin, and estradiol increased during the ascending portion of the pulse. The progesterone and gonadotropin results supported the hypothesis that the initial progesterone and gonadotropin increases that have been reported to occur in response to a single bolus luteolytic treatment with prostaglandin F_2α do not occur in response to the natural secretion of prostaglandin F_2α.