Level of marker enzymes in spermatogenesis on administration of PGF2 alpha in rats.

Intraperitoneal administration of PGF 2 alpha in rats significantly increased testicular acid phosphatase (p less than 0.05), decreased hyaluronidase (p less than 0.05), whereas the activities of 5'-nucleotidase, N-acetyl-B-glucosaminidase, B-galactosidase and uridine diphosphatase remained unaffected.     

Reflection-in-and-on-Action in Participatory Action Research: Toward Assessment <Emphasis Type="Italic">for </Emphasis>Learning

This article is about the use of oral assessment for learning and was based on a reflection-in-and-on-action approach within a participatory action research framework. The purpose of this paper was to argue for the incorporation of oral assessment in tertiary science as a fair, reliable and valid approach to assessment. This study found that the interactive nature of the oral assessments led to improved learning of content for learners from their peers and assessors. Assessors too learnt about their students as individuals, their study habits and critiqued their teaching from the oral assessments. They also learned from their co-assessors. Valuable lessons were learned for collaborative team teaching and assessing for the benefit of assessors and learners alike. This study also found that action research afforded the assessors a new way of doing things empowering them to conduct research in their own classrooms, with their colleagues and their learners.     

Hepatic phosphatidylcholine synthesis in deficiency of lysine and threonine: effect of malathion

Rats fed on a rice diet deficient in lysine and threonine showed increased activities of CDP-Choline pathway enzymes and incorporation of (methyl-3H)-choline into hepatic microsomal phosphatidylcholine, compared to rats fed on the same diet supplemented with lysine and threonine. However, the amount of microsomal phosphatidylcholine was significantly decreased in rats fed a deficient rice diet. These results suggest an enhanced phosphatidylcholine catabolism in rats fed on a rice diet deficient in lysine and threonine. Malathion administration reduced the amount of phosphatidylcholine in all the groups.     

Genotype-specific reduction in methyl nitrosourea (MNU) induced sister chromatid exchanges (SCE) in vivo during aging

We studied mice from five strains (BALB/c, C3H/HeSnJ, C57BL/6J, Csb and 129/ReJ) at two ages (young, 10 +/- 1 weeks; and old, 67 +/- 3 weeks) for the induction of sister chromatid exchanges (SCEs) in vivo by methyl nitrosourea (MNU). The SCE frequency is genotype-specific. The F1 phenotype resembles the 'low' responding parent. SCE induction is significantly lower in the older animals of each strain than their younger counterparts, and the reduction of SCE/cell with old age is strain-specific. A general explanation for these results must include strain differences in relative mutagenic sensitivity, genotype-specific pattern of reduction in DNA repair and other such factors affecting SCE formation, with old age.     

Lipid accumulation by a cellulolytic strain ofAspergillus niger

Lipid accumulation by a cellulolytic mold,Aspergillus niger, was studied. The amount of lipid accumulated ranged from 13.6–16.6% on various carbon sources, namely glucose, xylose, avicel (microcrystalline cellulose) and bagasse (a natural lignocellulosic substrate). Neutral lipids, phospholipids and glycolipids of the mycelia varied from 41.0–46.2%, 34.9–38.4% and 18.7–22.6% of total lipids, respectively. Unsaturated fatty acids comprised around 80% of total fatty materials with linoleic and oleic acid predominating. Of the four nitrogen sources tested, NH₄Cl was the best source for lipid synthesis from cellulose (bagasse). Optimum temperature range for growth and lipid synthesis was 25–30°C.     

Effect of mycotoxin (T-2 toxin) on catecholamine and Na+, K+-ATPase levels in rat epididymis

The effect of mycotoxin (T-2 toxin) on catecholamines and Na+, K+-ATPase activities in rat epididymis has been evaluated. Dopamine and norepinephrine levels were significantly elevated in the caput and corpus regions whereas their levels remained unchanged in the caudal part of the epididymis. Na+, K+-ATPase activity was significantly increased in all the three regions of rat epididymis as a result of the toxin treatment. These changes may suggest an adverse effect on epididymal functions in rats.     

Topographic localisation of insulinogenic and insulinoprival areas in the hypothalamus

Summary Electrical stimulation of hypothalamic areas through stereotaxically implanted electrodes were carried out in conscious male rhesus monkeys. There was a significant increase in immunoreactive insulin (IRI) following lateral hypothalamus (LHA) stimulation. An opposite response was obtained from ventromedial hypothalamus (VMH). Thus, insulinogenic and insulinoprival responses were obtained from feeding and satiety, suggesting a significant role of insulin in the regulation of food intake.     

A new neurosecretory system in fish,located in the gill region

Summary A peculiar neurosecretory system is reported in 6 teleost species;Clarias batrachus, Heteropneustes fossilis, Mystus seenghala, Ompak pabda, Glassogobius giuris andNotopterus notopterus. It is located in the gill region close to the pseudobranch or to the carotid labyrinth. The neurosecretory cells have been identified using stains specific for neurosecretion. The results are discussed in the light of the association of the neurosecretory system with the pseudobranch or the carotid labyrinth, and the airbreathing habit of these fishes.We are grateful to Prof. U.S. Srivastava for providing laboratory facilities and for encouragement. The work was financially supported by U.G.C. Research Project grant awarded to C.B.L.S., which is thankfully acknowledged. Thanks are due to M. Seal and Amarlata for technical help rendered.     

Intravenous thyrotropin releasing hormone (TRH) enhances the excitatory actions of acetylcholine (ACh) on rat cortical neurons

Summary I. v. administered TRH (1.25-10 mg/kg) enhanced the excitatory actions of iontophoretically applied ACh on spontaneously active cerebral cortical neurons of pentobarbital-anaesthetized rats. These observations are consistent with the hypothesis of a cholinergic-link in the anti-anaesthetic actions of exogenously administered TRH.