• Volume 96, Issue 1

      January 1987,   pages  1-80

    • Ovarian polymorphism in relation to reproductive diversity and associated histological and histochemical attributes in some sporophagous tubuliferan thysanoptera

      K Dhileepan T N Ananthakrishnan

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      Ovarian polymorphism involving oviparity, ovoviviparity and viviparity is discussed in relation to sporophagous species such asTiarothrips subramanii (Ramk.),Elaphrothrips denticollis (Bagnall) andBacterothrips idolomorphus Karny alongside with the comparative histology and histochemistry of polymorphic ovaries.

    • Host preferences of some acridids (Insecta: Orthoptera) in relation to some biochemical parameters

      K P Sanjayan T N Ananthakrishnan

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      Biochemical analysis of host plants of 6 species of acridids for their total protein, carbohydrates, phenols, free aminoacids, water and nitrogen content revealed significant correlation in regard to their host preferences, wherein the leaf water-nitrogen index as well as the total phenol composition appeared to play an important role.

    • Ecobehavioural and biological studies on two species of seed infesting thrips (Thysanoptera: Insecta)

      A Balu A Mohan Daniel

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      Ecobehavioural and biological aspects of two species of seed infesting thrips, vizChirothrips mexicanus Crawford andChiridothrips indicus Ramk. and Marg. are discussed with particular reference to their reproductive biology, population dynamics on different host plants and their damage potential to seed production of their primary host plants.

    • Light and electron microscopic observations on lipid droplets of the sebaceous flank gland of the shrew,Suncus murinus viridescens (Blyth)

      M Balakrishnan

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      Light and electron microscopic investigations have been made on the lipid droplets of the sebaceous flank gland alveoli of the Indian musk shrew,Suncus murinus viridescens. The undifferentiated sebaceous cells can be distinguished from the differentiating and differentiated cells by the absence of lipid droplets in the former. Adjacent droplets in the differentiating cells fuse to form larger droplets. Lipid droplets are also synthesized in the differentiating cells. Large accumulation of lipid droplets are seen in well differentiated cells. The cells of the inner layer of the sebaceous alveoli disintegrate and the holocrine products are liberated into the lumen. The probable role of mitochondria and polyribosomes in the synthesis and development of lipid droplets in the sebaceous cells of the flank gland is discussed.

    • Quantitative analysis of carbohydrases in the crystalline style of some intertidal bivalve molluscs

      P Shahul Hameed A L Paulpandian

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      Amylase activity in different pH ranging from 3·6 to 8·0 and activity of sucrose, maltose, trehalase, raffinase, lactase, glycogenase, pectinase, chitinase, carboxy methyl cellulase and cellulase at their respective optimum pH were quantitatively estimated in the crystalline style of intertidal bivalves,Crassostrea madrasensis, Meretrix meretrix, Meretrix casta, Katelysia opima andDonax cuneatus. Amylase was the most active among all enzymes tested. A maximum activity of 137·5 μg/mg/h was recorded in the style ofKatelysia opima while the activity was minimal inDonax cuneatus (39·3 μg/mg/h). Two pH optima were recorded for style amylase ofCrassostrea madrasensis (6·0 and 6·8) andKatelysia opima (5·6 and 6·8). But the activity was higher at higher optimum pH. The enzymes hydrolysing oligosaccharides were weak in most cases or absent. The enzymes acting on reserve polysaccharides such as amylase and glycogenase showed maximum activity in the species tested. However the activity of enzymes degrading structural polysaccharides such as cellulase, carboxy methyl cellulase, pectinase and chitinase was either at a low level or absent. The role of the style enzymes in the extracellular digestion of bivalves is discussed.

    • Glycogen level and glycogen phosphorylase activity in the eggs of silkwormBombyx mori L.

      P M Chandrashekar Geetha Bali

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      The glycogen content of the eggs of silkwormBombyx mori L. was analysed at intervals during the course of embryonic development and diapause. Changes in the glycogen levels were also examined in acid treated eggs in which diapause has been broken. These studies showed significant differences in glycogen utilisation pattern in the diapause and non-diapause eggs. The activity of the enzyme glycogen phosphorylase was also found to exhibit different patterns in the two types of eggs. Our studies indicate that this enzyme plays an important role in the metabolic changes which occur during diapause in silkworm eggs.

    • A shift in metabolic pathway ofSarotherodon mossambicus (Peters) exposed to thiodon (endosulfan)

      M Vasanthi M Ramaswamy

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      Total oxygen consumption, glycogen content and succinic dehydrogenase levels in liver, muscle and heart in normal and thiodon-exposed (to sub-lethal concentration for 48 h and to lethal concentration for 6 h)Sarotherodon mossambicus (Peters) were studied. While oxygen consumption of the fish dropped to 43 and 35% respectively under sub-lethal and lethal exposures, the magnitude of decrease in tissue glycogen content as well as tissue succinic dehydrogenase level followed a uniform order of liver > muscle > heart in both the exposures. Reduction in oxygen uptake and tissue glycogen levels were indicative of the onset of hypoxia involving utilization of stored glycogen by the fish under thiodon exposure. The inhibition of succinic dehydrogenase levels in the 3 tissues of thiodon-exposedSarotherodon mossambicus, while indicating the impairment of aerobic metabolism, is also suggestive of a shift from aerobic to anaerobic metabolism in the fish under pollution stress.

    • Aspects of culture:Acanthamoeba astronyxis (Ray and Hayes 1954) from Bay of Bengal coasts, India

      Mrinal Ghosh Amalesh Choudhury

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      Acanthamoeba astronyxis strains, isolated from intertidal belts of Sagar Island (21°30′ to 21°50′ N and 88°04′ to 88°08′ E) facing Bay of Bengal, were cultured in saline distilled water agar medium supplemented withEscherichia coli as food bacterium. Population growth in bay water agar, cerophyl bay water agar and soil extract distilled water agar were compared with special reference to devised saline distilled water agar medium. The overall growth showed little variation over ranges of media salinity (5–30‰). However, greater values were encountered in media of intermediate range. Isolate from mangrove litter-soil of highest high tide belt (strains) grew more efficiently in cerophyl bay water agar and soil extract distilled water agar media while mid-littoral and lowest low tide isolates preferred bay water agar and saline distilled water agar media more.

    • Development and survival ofMythimna separata (Wlk.) on some host plants during winter at Hisar

      Ram Singh J P Chaudhary

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      Survival and post embryonic development of the oriental armyworm,Mythimna separata (Wlk.) was studied on 5 host plants, viz sorghum, maize, sugarcane, Johnson grass and napier grass during winter months (15 November to 7 March) under laboratory conditions. Variations in different parameters like larval survival (10·3–60·3%), size of larvae (7·33–29·67 mm), larval weight (25·5–493·1 mg for 26 days old larva), size of pupa (15·0–16·49 mm), pupal weight (184·9–249·5 mg for 2–4 days old pupa), pupation (3·3–38·9%), developmental period (74·8–109·8 days) and moth emergence (3·4–50·0%) were significant on different foods. Low temperature and humidity conditions during experimental period resulted in complete mortality of female pupae reared on napier grass, Johnson grass and maize whereas in case of males 60–100% moths were crippled winged. However, adults emerged on sorghum and sugarcane foods were normal except 28·7% males in sorghum were crippled. Total growth index was also higher on sugarcane (0·45) and sorghum (0·24) indicating their suitability in carrying over of winter pest population.

    • Food utilization and surfacing activity ofChanna striatus fry in relation to quality of food

      K Sampath E Vivekanandan

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      Effects of food items (mosquito larva, pupa, chironomous larva and chopped pieces of the fishLepidocephalichthyes thermalis) on food utilization and surfacing activity ofChanna striatus fry were studied. Test individuals fed on live food organisms surfaced 94–117% more frequently, consumed 23–119% more rations/day and, on an average, converted 33% more than those fed on pieces ofLepidocephalichthyes thermalis. Regardless of the quality of food,Channa striatus surfaced about 60 times/h before each meal and the frequency increased to 130 times/h 3–6h after the meal was offered and returned to the prefeeding level 18–21 h after the meal.

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