• Volume 91, Issue 4

      July 1982,   pages  349-406

    • A comparative study on certain biochemical aspects of red and white myotomal muscles of the black skipjack tuna,Euthynnus affinis Cantor

      N Gopinathan Pillai K M Alexander

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      The biochemical assay of certain metabolites of the red and white myotomal muscles of the tuna,Euthynnus affims Cantor has been carried out. The metabolites exhibited a marked variation in their distribution pattern in red and white muscles. The narrow red fibres are characterised by higher levels of lipid, glycogen, myoglobin and SDH while the broader white fibres had lesser amount of the above metabolites. The distribution of metabolites—the myoglobin and SDH, revealed a gradientfrom the superficial towards the inner layers of the red myotomal muscle in both the pectoral and middle regions. The physiological relevance of these biochemical variations in diverse regions of the red and white muscle is discussed.

    • Circadian basis for the photoperiodic response in the male blackheaded bunting (Emberiza melanocephala)

      Vinod Kumar P D Tewary

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      Short day (6 hr light in a 24 hr cycle (ld 6 ∶ 18)) inhibits growth and development of the testes in male blackheaded buntings, whereas the same (6 hr) nonstimulatory photoperiods in a 36 hr cycle (ld 6 ∶ 30) induce complete testicular recrudescence and development. In another experiment of 24 hr cycles, using the same (6 hr) main photoperiod, testes were stimulated when the dark period was interrupted by light at 12 to 13 hr after the onset of basic photoperiod (ldld 6 ∶ 6 ∶ 1 ∶ 11). The results appear to conform to the tenets of the external coincidence model.

    • Steroid metabolism in target related to nuptial plumage production in the Baya weaver bird

      V C Kotak G K Menon

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      To elucidate the possible utilization of gonadal sex hormones by the nuptial plumage producing skin, histochemical localization of 3β-, 3α- and 17βhydroxysteroid dehydrogenases was carried out in the skin from crown region (characterized by bright yellow plumage) and ventrum, and testes of the Baya weaver birdPloceus philippinus (L) during the breeding phase. Results indicate higher activity of 17β-hydroxysteroid dehydrogenase in the crown skin, when testosterone was used as substrate. Possibly, skin from the crown region actively metabolizes androgens and this in turn is correlated to the production of nuptial plumage.

    • Sex pheromone in a stomatopod crustaceanSquilla holoschista

      M Deecaraman T Subramoniam

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      The stomatopods are well-known for their aggressive and agonistic encounters. The males are normally aggressive; the females too in the non-reproductive condition show such a behaviour with males. InS. holoschista mating is frequent as well as repetitive. The present paper explains whether there is any involvement of sex pheromone. The sex pheromones are considered to be present in ovaries, cement glands as well as oviducal extractions. These substances were tested for their pheromonal activity. The results indicate that there may not be such attraction as evidenced by the lack of mating gestures from the isolated males in the presence of these substances. It is therefore suggested that the mating in the stomatopod,S. holoschista is indiscriminate. The physiological effect of such a repeated and indiscriminate mating on the female is discussed.

    • A new species ofArgulus Muller (Crustacea: Branchiura), with a note on the distribution of different species ofArgulus in India

      P Natarajan

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      This paper describes a new species ofArgulus, Argulus mangalorensis collected from the estuarine stretch of Nethravathy river of Mangalore, S. India. The distribution of different species ofArgulus reported from India is also indicated.

    • The effect of cephalic transection on the micromorphological changes in the ventral nerve cord-neurosecretory system of earthworm,Metaphire peguana (Rosa, 1890) during anterior regeneration

      D K Nanda P S Chaudhuri

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      Transection of anterior 5 segments inMetaphire peguana engenders characteristic changes in the functional activity of the ventral nerve cord-neurosecretory system in the event of cephalic regeneration. Of the two types of neurosecretory cells, the moderately stained cells remain more susceptible when the cell structure, location of nucleus, amount of secretory inclusions and their transportation to the zone of accumulation are considered. Overall engorgement of neurosecretory substances refrained from axonal transport, moderate axonal flow coupled with slight depletion and finally acute depletion at 24, 48 and 72 hr after amputation respectively are some of the notable features registered in course of this investigation. Disarray in the sequential changes involved in the secretory dynamics of neurosecretory cells, as well as extent of NSM accumulation both within and outer periphery of the ganglia provide evidence for the utilisation of material through repaired vascular systems during regenerative proliferations of anterior segments.

    • Studies on preference ofCallosobruchus maculatus Fabricius to some high yielding varieties of arhar (Cajamis cajan L.)

      Satya Vir

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      The oviposition response and development ofCallosobruchus maculatus Fabricius were studied on 14 high yielding varieties of arhar. There was significant difference among the varieties in the amount of food consumed per grub. The average development period was not dependent on the amount of food consumed. The development of grub was also not better on the grain preferred by the beetle for opposition. There was significant difference among the varieties in the loss of 100 seed weight. Average weight of female was more than the male developed on all varieties. On the basis of food consumed per grub and loss of 100 seed weight as a combined criterion, the varieties are grouped into least susceptible, intermediate in susceptibility and the most susceptible varieties.

    • Three new species of haematozoans from freshwater teleosts (pisces)

      B D Joshi

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      Two new species of haematozoans,Trypanosoma aori (sp. nov.) andTrypanoplasma mysti (sp. no.v.), were found harbouring the blood plasma of freshwater teleosts,Mystus aor, whileTrypanoplasma atti (sp. nov.), was found in the plasma of another cat fishWallago attu. The two hosts are new records for these parasites. All three species of the parasites described here showed characteristic polymorphism.

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