Seasonal changes in plasma steroid levels in relation to ovarian steroidogenic ultrastructural features and progesterone receptors in the house gecko, Hemidactylus flaviviridis, in Oman.

A comprehensive study of the annual ovarian cycle in the house gecko, Hemidactylus flaviviridis, was conducted in Oman. Circulating estradiol (E(2)), progesterone (P), and testosterone (T) were measured during the active and inactive phases of the cycle. The steroid levels were related to the steroidogenic ultrastructural features such as the abundance of smooth endoplasmic reticulum (SER), the presence of cisternal whorls, and close association of lipid droplets with swollen vesiculated mitochondria and SER. The steroids were measured using a sensitive detection technique HPLC-MS/MS. E(2) levels began to rise in January at the onset of vitellogenesis and continued to rise between February and May relative to ovulation, postovulation, gravidity and oviposition. Afterwards, E(2) remained low during the inactive phase (June-December). P levels increased significantly in March and peaked in April, which coincided with luteinization. P levels began to decline relative to luteolysis (May-June). Afterwards, it remained low throughout the inactive phase. T levels rose significantly in March-April coinciding with vitellogenesis, but decreased rapidly and significantly in May and remained low during the inactive phase. Progesterone receptors (PR), identified using immunohistochemistry, were strongly expressed during the breeding period, but were absent during the non-breeding period. The appearance of the steroidogenic ultrastructural features in the preovulatory and lutein granulosa cells was correlated with the significant rise in the three steroid levels and the PR. As the steroid levels declined, the granulosa cells underwent a general degeneration and disruption of the associated steroidogenic features.

Coastal sewage discharge and its impact on fish with reference to antibiotic resistant enteric bacteria and enteric pathogens as bio-indicators of pollution.

Presence of antibiotic resistant bacteria as bio-indicators of pollution was monitored in fish (colons and gills) and in sewage treated effluent (STE) in two marine sites in the Gulf of Oman, Muscat. One site was polluted as the sewage effluent STE was directly discharged into the sea while the unpolluted site was 10 km away. A total of 42 water samples (250 mL each) were collected from both sites. In the polluted site, 14 samples were taken directly from the STE discharge point and 14 from the surrounding area near the STE discharging point (7-10 m). Water and fish samples were collected from polluted and unpolluted sites. Chlorine and nitrate levels were significantly higher in STE samples. A significant difference (P<0.005) was found in total bacterial count of fish colon and gills in the two sites. Most probable number (MPN) was significantly higher in STE and polluted seawater over unpolluted. Coliforms were detected in the polluted site only. A total of 320 target enteric normal flora of animals and pathogenic species were isolated from 10 genera taken from water and fish samples. The isolates were exposed to 14 antibiotics. Most of the isolates were resistant to at least one antibiotic with ampicillin was the dominant antibiotic. This is a clear indication that sewage effluent causes contamination of marine wildlife along coastal lines.