Polymorphisms involving the transmembrane domains of human TAP2

Correspondence to: S. Pillai.     

Performance and survival of different races of Puccinia graminis f.sp. tritici on detached leaves of wheat

The detached leaf culture of Puccinia graminis f.sp. tritici was tested with eight races and two biotypes of the pathogen. The inherent characteristics of the races were similar to those in intact plants. Continuous maintenance of races in pure culture on detached leaves showed the usefulness of the technique for multiplication of inoculum as well as for maintenance of races in other basic studies.     

Monsoon-dependent breeding in the field crab Paratelphusa hydrodromous (Herbst)

The reproductive cycle of the field crab Paratelphusa hydrodromous (Herbst) was determined by direct field observations as well as by calculating the percentage of ovigerous females in a Madras population for a period of three years. The females breed annually in a single spawning. These observations, corroborated by histological studies on the nature of the ovary, indicate that gametogenic activity starts in December and vitellogenesis is completed during January-May. Spawning commences in the last week of June or first week of July with the release of brood in the month of September (1979), October (1978) or November (1980) during northeast monsoon. The smallest female crab showing spawning had a carapace width of 3.1 cm and the largest spawning crabs measured 5.5 mm. The mean number of eggs spawned in the smallest crab was 247 and that in the largest crab was 417. Mean incubation was 41 ± 12.388 days. Vitellogenesis and spawning occurred at peak temperature conditions. Though the time taken for vitellogenesis and commencement of spawning were constant for the study period, the duration of retention of the juveniles in the brood varied with the onset of monsoon.     

Effect of ayurvedic medicines on beta-glucuronidase activity of Brunner's glands during recovery from cysteamine induced duodenal ulcers in rats

Biochemical and histochemical studies revealed decreased beta-glucuronidase activity in the Brunner's glands of duodenal ulcerated rats. The enzyme activity showed gradual increase during recovery. Rats treated with a mixture of Ayurvedic medicines (Glycyrrhiza glabra, Terminalia chebula, Piper longum and Shanka Bhasma) recovered faster with concomitant increase in beta-glucuronidase activity in the Brunner's glands. It can be concluded that Ayurvedic medicines used do not act as antacid but improve the secretory status of Brunner's glands involved in the protection against duodenal ulcer.     

Microplate assay of elevated esterase activity in individual pyrethroid-resistant mosquitoes

Involvement of esterase-mediated hydrolysis as a mechanism of pyrethroidresistance in three species of mosquitoes,viz., Aedes aegypti, Culex quinquefasciatus andAnopheles Stephensi was investigated by microplate assay of Β-esterases in individual larva and adult female and male mosquitoes. Assuming an absorbance value of 0.4 and above at 555 nm as the threshold level of elevated esterase activity which confers resistance, frequency distributions of such individual test mosquitoes were constructed in resistant and susceptible populations. The results indicate the involvement of ester hydrolysis of Pyrethroids as a predominant mechanism of pyrethroid-resistance in the larvae ofCulex quinquefasciatus but not inAedes aegypti. However, a marginal role of esterases is indicated in the larvae ofAnopheles stephensi.