Evolutionary relationships of flying foxes (genus Pteropus) in the Philippines inferred from DNA sequences of cytochrome b gene.

Six flying fox species, genus Pteropus (four from the Philippines) were investigated using complete cytochrome b gene sequences (1140 bp) to infer their evolutionary relationships. The DNA sequences generated via polymerase chain reaction were analyzed using the neighbor-joining, parsimony, and maximum likelihood methods. We estimated that the first evolutionary event among these Pteropus species occurred approximately 13.90 +/- 1.49 MYA. Within this short period of evolutionary time we further hypothesized that the ancestors of the flying foxes found in the Philippines experienced a subsequent diversification forming two clusters in the topology. The first cluster is composed of P. pumilus (Philippine endemic), P. speciosus (restricted in western Mindanao) with P. scapulatus, while the second one comprised P. vampyrus and P. dasymallus species based on the analysis from first and second codon positions. Consistently, all phylogenetic analyses divulged close association of P. dasymallus with P. vampyrus contradicting the previous report categorizing P. dasymallus under subniger species group with P. pumilus. P. speciosus, and P. hypomelanus. The Philippine endemic species (P. pumilus) is closely linked with P. speciosus. The representative samples of P. vampyrus showed a large genetic distance of 1.87%. The large genetic distance between P. dasymallus and P. hypomelanus, P. pumilus and P. speciosus denotes a distinct species group.

Evidence of ovulation in goats (Capra hircus ) with short estrous cycle and its occurrence in the tropics.

The influence of season and exposure to buck on the length of the estrous cycle were determined in 32 normally cycling native goats of different ages and parity. The estrous cycle durations were classified as short, medium and long. Ten goats (31%) exhibited medium length estrous cycles; 22 animals (69%) exhibited a combination of short, medium and long estrous cycles. Of the 155 estrous cycles studied, 15% were short, 72% were medium and 13% were long. Short estrous cycles were significantly shorter (P < 0.01) in estrus duration than medium or long estrous cycles. Significant differences (P < 0.05) for estrous cycle length and estrus duration were found between does but not within does. The presence of a buck for 8 to 16 h showed no significant effect on the length of the estrous cycle or on estrus duration, but a 24-h exposure period to a buck yielded shorter estrous cycles and estrus duration than found in the unexposed control group. Estrous cycles were significantly shorter (P < 0.01) in October, when rainfall is 57.9% of the annual total, and significantly longer (P < 0.01) in February, when rainfall is low at 0.2% of the annual total. A negative linear relationship (r = -0.87) was observed between estrous cycle and rainfall. Twenty-eight (90.3 %) of the short estrous cycles were ovulatory. The short cycles had a relatively lower ovulation rate than medium and long estrous cycles. The results indicate that the short estrous cycle in goats is associated with ovulation, and its occurrence in the tropics is related to rainfall.

Prostaglandin E2 levels in uterine tissues and its relationship with uterine and luteal progesterone during the estrous cycle in dairy cows.

Endometrial tissue homogenates obtained at luteal and follicular stages of the estrous cycle were determined for prostaglandin E2 and progesterone contents by EIA and RIA, respectively. In Experiment 1, the concentrations and changes of PGE2 in uterine tissues collected by biopsy before slaughter and subsequent samples collected at 30, 60 and 90 min after slaughter were measured. No significant differences were observed in the concentration of PGE2 preslaughter or at 30 and 60 min post slaughter. However, there was a significant decrease (P<0.01) in PGE2 concentration 90 min post slaughter. In Experiment 2, the concentrations of PGE2 in the ipsilateral and contralateral horns in relation to corpus luteum function were compared. A significant (P<0.05) interaction was found between stages of estrous cycle (luteal vs follicular) based on CL progesterone content, and type of uterine horn (ipsilateral vs contralateral) on uterine PGE2 levels. The PGE2 concentration was significantly higher (P<0.01) at luteal phase than at follicular phase. During the luteal phase PGE2 concentrations in tissues of the uterine horn ipsilateral to the corpus luteum was significantly higher (P<0.01) than the contralateral horn. The PGE2 concentration was low and did not differ significantly between horns during follicular phase. A parallel increase (luteal: high) and decrease (follicular: low) in PGE2 and progesterone concentrations were observed. Correlations were observed for CL progesterone and uterine PGE2 concentrations as well as for PGE2 and progesterone concentrations in uterine tissues (r=0.70 and r=0.60, respectively). The results show that the increase in PGE2 concentrations in uterine tissues coincides with the high uterine progesterone concentrations during luteal phase.