• Volume 76, Issue 6

      December 1972,   pages  229-270

    • Effect of copper acetate and asphalt on gonadal activities and the correlated changes in the pre-optic nucleus of two genera of teleostean fishes,Clarias batrachus (Linn.) andOphiocephalus punctatus (Bloch)

      D Khosa K Chandrasekhar

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      Asphalt and copper acetate are shown as chemical inductors which can enhance maturation of ova and increase vitellogenesis in the two genera of teleostean fishes,Clarias batrachus andOphiocephalus punctatus.

      Along with the study of their effect on the ovaries, changes seen in the pre-optic nucleus of these fishes have also been studied. It is brought out that a distinct correlation exists between the ovarian activity and the fuchsinophil content of the neurons of the pre-optic nuclei of these two fishes.

      Copper acetate is seen to hasten enlargement of a large number of oocytes while asphalt increases their yolk content. It is also noticed that in the eggs with more yolk the granulosa is prominent.

    • Effect of mammalian estrogens and progesterone on the hypothalamo-adenohypophysial complex of ovariectomised cat-fishClarias batrachus (Linn)

      K Chandrasekhar D Khosa

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      Exogenous estrogen and progesterone are found to influence the Gomori positive secretion in the neurons of the supra-optic nucleus ofClarias batrachus. Prolonged administration of progesterone alone causes abnormal enlargement of the neurons of the pre-optic nucleus and the formation of unusually large vacuoles in the oocytes.

      The observations in this experiment are thus indicative of a correlatory pre-optico-ovarian activity. Progesterone in combination with estrogen enhances the accumulation of fuchsinophil material in the neurons of the pre-optic nucleus while complete absence of the ovarian hormones causes depletion of the Gomori positive material and brings in reduction in cell size.

      In the pituitary progesterone in combination with estrogen brings to prominence, the fuchsinophils and the basophils go into insignificance. On the other hand, in the ovariectomised control fishes, the basophils gained prominence. But progesterone alone seems to have no significant effect on either of them.

    • Amino tripeptidase activity in three teleost fishes

      K V Sastry

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      Amino tripeptidase is secreted by the intestinal mucosa, hepatopancreas, pyloric caeca and pancreas in the fishes examined here. The optimum pH for the activity is between 7·0–7·6 in the above portions of the alimentary canal. The optimum pH varies from one portion to other, and also from one species to other. The secretion of amino tripeptidase by the pancreas indicates that the distribution of proteases in fishes is not similar to that of mammals.

    • Histochemical recognition of carbohydrate-protein yolk bodies in invertebrate oocytes

      K Shyamasundari

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      Many of the histochemical tests recommended for the detection of amyloid a pathological deposit in animal tissues have been found to be useful to demonstrate carbohydrate-protein yolk bodies in the oocytes of amphipods and turbellarians. The Congo red tests are especially important. However, the apparent similarity cannot perhaps be stressed too far because of the failure of oocyte yolk bodies to react positively to alcian blue or Hale’s iron test or even to iodine test to all of which amyloid is more or less positive.

    • Anatomical studies on succulent cladodes inCasuarina equisetifolia Linn

      A N Rao

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      Casuarina equisetifolia Linn. is a well-known xerophytic plant of the tropics and sub-tropics with thin, wiry, cladodes. Contrastingly in coastal plants of Malaya and Singapore succulent branehes are formed. The anatomical characters of the fleshy cladodes and the shoot apices are described in this paper, in comparison with the normal, non-succulent structures. Causal factors for the succulent habit in this plant are indicated and the significance of such a variation is comparatively discussed with reference to corresponding literature.


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