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Showing papers on "Bufo melanostictus published in 1986"


Journal ArticleDOI
01 May 1986-Oikos
TL;DR: The incidence of atresia, as observed in the ovaries sampled throughout the year, suggests that about two thirds of the toads preparing for spawning are primiparous, leaving only one third to represent iteroparity within the population.
Abstract: In the Bangalore population of Bufo melanostictus the ovarian cycles in individual toads are characterized by synchronous growth of the vittellogenic oocytes and by asynchrony with respect to stage in the ovarian cycle among the toads. However, late ovarian cycles predominated during the period of August-October. The incidence of atresia, as observed in the ovaries sampled throughout the year, suggests that about two thirds of the toads preparing for spawning are primiparous, leaving only one third to represent iteroparity within the population. Body size varied greatly at first maturation, when somatic growth declined or stopped. The greatly varying body size is consistent with a seasonal timing of sexual maturation preparing for the main breeding season, which coincides with the height of the monsoon rains during August-October.

50 citations




Journal ArticleDOI
TL;DR: Broad based differential regions were detected in microphotometric tracings of Giemsa stained but unbanded Bufo melanostictus chromosomes, suggesting that GiemsA stained bandings could be superimposed phenomena.
Abstract: Broad based differential regions were detected in microphotometric tracings of Giemsa stained but unbanded Bufo melanostictus chromosomes. This was facilitated by the combination of (1) a very small photometric step size of 0.05μ, (2) scanning at “minimum effective aperture” with the magnification of the chromatid width adjusted to fall within it, and (3) direct multidirectional tracing along the exact pathway of the chromatid arms. It seems possible that Giemsa stained bandings could be superimposed phenomena since they are consequent upon various treatments to the chromosome, including some which produce gross structural alterations.B. melanostictus is the common toad found in gardens of the South East Asian region, whose karyotype has not been previously documented because of the dif-ficulty in culturing its cells in vitro. We succeeded by using medium enriched with 10, 000 mol. wt. ultrafiltrate of unfertilized eggs of the female. The karyotype (2n=22) consisted of all metacentric chromosomes except for a single submetacentric ele-ment. By size, the chromosomes were divisible into 2 groupings, a bigger and a smaller, easily discernible by simple inspection.

1 citations


Journal ArticleDOI
TL;DR: Time course study shows that the activity in vitro becomes steady after 3 min of incubation in all the cases, except the immature ones in which it sharply declines, which suggests that similar to mammalians prostaglandin-synthetase, the toad ovary enzyme is also regulated by luteinizing hormone.
Abstract: Prostaglandin-synthetase activity has been measured in the microsomal fraction of developing toad (Bufo melanostictus) ovary using arachidonic acid as the substrate. Indomethacin (0.74μM) and aspirin (0.35μM) inhibit this activity. The activity is maximum in immature ovary and its level gradually decreases with maturity of the organ till the breeding season arrives, when it rises again. Time course study shows that the activityin vitro becomes steady after 3 min of incubation in all the cases, except the immature ones in which it sharply declines. Soluble supernatant was found to contain some inhibitory factor(s), which is partially inactivated by heating at 100°C for 5 min (∼ 43%). Intraperitoneal injection of equine luteinizing hormone stimulates this enzyme activity in the mature ovary during non-breeding season. This suggests that similar to mammalians prostaglandin-synthetase, the toad ovary enzyme is also regulated by luteinizing hormone

1 citations