Seasonal changes in radioiodine uptake and epithelial cell height of the thyroid gland in the freshwater teleosts Esomus danricus (Ham.) and Mystus vittatus (bloch) under varying conditions of illumination

Summary The thyroid gland of Mystus vittatus and Esomus danricus showed seasonal activity in its epithelial cell height and radioiodine uptake. These two indices of activity agree in E. danricus. Under normal photoperiods both species exhibited two phases of optimum activity, one in April through May, the other in September. The active periods were characterized by high iodine uptake and increased follicular cell height. These peaks of activity alternated with more quiescent phases, minimal iodine uptake and low follicular epithelium. In specimens exposed to constant illumination the active and quiescent phases were advanced by two months. But for this change the general pattern of activity was the same as that in animals kept under normal photoperiodic conditions. Specimens subjected to total darkness showed a higher level of activity throughout the year in comparison to the other two groups. However, a distinct seasonal cycle, which was evident with normal photoperiods and continuous illumination, was absent in total darkness.I am greatly indebted to Dr. A. G. Sathyanesan, Banaras Hindu University, for his encouragement, and to Professor S. P. Ray-Chaudhuri, Banaras Hindu University, for providing laboratory facilities.     

Biochemical Aspects of Parasitism by the Angiosperm Parasites: Starch Accumulation

The investigation dealt with starch accumulation in four species of Cuscuta (Cuscuta campestris, C. indecora, C. planiflora and C. reflexa), a leafy mistletoe (Dendrophthoe falcata) and a chlorophyll-lacking root parasite (Orobanche aegyptiaca). The highest content of starch occurred In O. aegyptiaca, with a maximum of 45 per cent of dry weight Starch in Cuscuta filaments and mistletoe leaves showed a maximum of about 10 per cent of dry weight. The starch content varied along the length of the Cuscuta vine, with a maximum in the apical region. Orobanche had a higher starch content when it was still submerged than it was fully developed. Cuscuta vines did not show any marked diurnal alteration in the starch content. The content of ethanol-soluble carbohydrate was only a tenth of the starch in Orobanche, but was relatively higher in the other parasites. the neutral sugars in Cuscuta filaments were sucrose and glucose, whereas fructose was also present in mistletoe and Orobanche. Raffinose and stachyose were absent or present only ill traces in parasite tissue. Starch granules from Cuscuta and Orobanche bad ADPG/UDPG-starch synthetase activity and homogenates starch phosphorylase activity. The former enzyme appeared to be responsible for synthesis of starch and the latter for utilization. The four different species of Cuscnta, growing on alfalfa, had more or less the same activity of starch synthetase and also of phosphorylase activity. Hosts infected by Cuscuta had significantly less starch per plant than the controls. A characteristic feature of invasion by Cuscuta and Orobanche was increased phosphorylase activity in the host tissues. The protein content of the tissues of Cuscuta and Orobanche was of a lower level than that of the host shoot system or foliage, indicating that the parasite differed from the host in having a higher carbon (of starch) to nitrogen (of protein) ratio.     

Studies in the mineral nutrition of Japanese mint

Summary This paper presents the results of an experimental enquiry into the effects of phosphorus deficiency and age on the nitrogen metabolism in component parts of mint plants (Mentha arvensis var.piperascens).Estimation of various nitrogenous fractions i.e. ammoniacal, nitrate, amide, rest, total soluble, total insoluble and total nitrogen were made in leaf, stem and root of mint plants, collected from full-nutrient and phosphorus-deficient cultures, at subsequent stages of the life cycle. The outstanding effect of phosphorus deficiency was noted: an increased accumulation of amides resulting in poor formation of proteins which suggested interference in protein synthesis beyond amide stage. Leaf showed maximum percentage of nitrogen in the insoluble form. The stem served as channel for transport and storage and invariably showed high concentration of soluble nitrogen fractions.     

Ultra-violet induced mutants of blue-green algae

Summary Mutant strains of Anabaena cycadeae Reinke have been isolated after ultra-violet irradiation. All the four mutants described appear to be stable. They have been identified on the basis of their pigment composition, nutritional requirements, photoautotrophic growth and reaction to light. Strain 10 M ₁ ^L is a non-nitrogen-fixing mutant as indicated by its inability to grow on basal medium (AA) deficient in combined nitrogen. Strain 10 M ₁ ^L /10 M ₁ ^D is apochlorotic, and grows very slowly on medium AA-3 both in light and dark but comparatively better under the latter condition. Strain 10 M ₁ ^L /10 M ₂ ^D is deficient in -carotenoid, photosensitive and able to grow in dark only on AA-3 medium while strain 10 M ₁ ^L /10 M ₃ ^D is a photoheterotrophic nitrogen-fixer.     

Studies with bovine parainfluenza - 3 virus in u.a.R. (Egypt)

A bovine strain of myxovirus parainfluenza-3 (MP3) virus, designated S virus, was isolated from lung tissue collected from cattle with respiratory illness in 1963. The virus agglutinates mammalian and avian erythrocytes, and is sensitive to ether, sodium desoxycholate and trypsin. It grows in primary calf kidney, buffalo kidney, dog kidney, camel kidney and MS cell cultures. The S virus forms well-defined plaques in buffalo and calf kidney cells on the 5th or 6th day after inoculation. Examination of cell cultures following inoculation with S virus revealed giant cell formation, and introcytoplasmic and intranuclear inclusions. At 37 degrees C the virus titer dropped from 10(10.4) to 10(2.6) in 3 days. Virus was completely inactivated at 56 degrees C within 15 minutes. Growth-curve studies in tissue culture monolayer cells revealed a latent period of 10 hours. The intracellular virus titer was slightly lower than that of extracellular virus. The isolate was identified as MP3 virus by serum neutralization and hemagglutination-inhibition tests. Antibodies (HI) to S virus were shown to be present in a significant proportion of Egyptian cattle. The epidemiological significance of MP3 (bovine strain) virus in U.A.R. is discussed.     

Argyrophile and argentaffin reactions in individual granules of enterochromaffin cells of reserpine treated guinea pigs

Summary The individual granules of enterochromaffin cells of normal and reserpine treated guinea pigs have been studied by staining slides of the duodenum first by an argentaffin method and subsequently by an argyrophile method. Some argentaffin cells can be shown to contain not only argentaffin granules, but also granules that are purely argyrophile. The relative number of such argentaffin cells is greatly increased following administration of reserpine, as depletion of their 5-hydroxytryptamine content converts argentaffin granules into purely argyrophile ones. On the basis of this finding it is confirmed that the argyrophile granule is merely an argentaffin granule depleted of its 5-HT content, and that the argyrophile (nonargentaffin) and the argentaffin cells represent different phases of a secretory cycle.This investigation was supported by a grant from the Indian Council of Medical Research. I am grateful to Ms. Ciba of India Ltd. for making available reserpine (Serpasil) and solvent for reserpine. It is a pleasure to thank Mr. Anand Parkash for technical assistance and Mr. M. L. Sharma for the photographs.     

Bionomics ofTrioxys indicus [Hym.: Aphidiidae], a parasitoid ofAphis craccivora [Hem.: Aphididae]: 31. Effect of host haemolymph on the numerical response of the parasitoid

The influence of kairomones on the numerical response of the parasitoidTrioxys indicus against its hostAphis craccivora at its varying density was studied. The kairomones (applied as aqueous extract of the host) significantly enhanced the rate of parasitisation and multiplication and the area of discovery of the parasitoid and also the K-values of mortality of the host at all parasitoid densities introduced (1, 2, 4, 8, 12 and 16 parasitoids) into troughs having about 200 hosts. The sex-ratio of F₁ offspring decreased at lower parasitoid densities and remained more or less unchanged at higher parasitoid densities after the application of kairomones. The present findings indicate that if kairomones are applied properly, the number of hosts destroyed by a stimulated parasitoid will be about 200, twice the number reported earlier, thus fewer parasitoids will be needed to regulate an estimated population of the hosts.