Disruption of pituitary-ovarian axis by carbofuran in catfish, Heteropneustes fossilis (Bloch)

We investigated whether carbofuran (CF), a carbamate pesticide, at sub-lethal concentration had any adverse effects on reproductive function of the Indian catfish, Heteropneustes fossilis. 17β-Estradiol content of serum and ovary of pre-spawning (P) and spawning (S) fish was reduced after sub-lethal concentration of carbofuran treatment (0.5–2 mg/ml, 30 days). After 30 days of CF treatment, the serum and ovarian vitellogenin levels of fish at the P stage were also reduced but remained unaltered in the S stage. The staining intensity of the pituitary gonadotrophs of the pre-spawning fish was significantly higher in CF-treated fish compared to controls suggesting the inability of the pituitary gonadotrophs to release gonadotropin following CF treatment. CF thus acts as an antiestrogenic, endocrine-disrupting agent in fish, possibly targeting the pituitary-gonad axis.     

PERMANENT GENETIC RESOURCES: Ten novel polymorphic dinucleotide microsatellite loci cloned from the Antarctic fur seal Arctocephalus gazella

Ten new dinucleotide microsatellite loci were isolated from the Antarctic fur seal Arctocephalus gazella. These markers should prove useful for studying the reproductive ecology of Antarctic fur seals and other related pinniped species.     

Influence of aflatoxin B1 on seed germination, seedling growth, chlorophyll and carotenoid contents of mustard (brassica juncea L. var. pusa bold) seeds

Five different concentrations (100, 250, 500, 1000 and 2000 μg/L of aflatoxin B₁ were found to be inhibitory to seed germination and seedling growth (root and shoot lengths) of mustard seeds (variety Pusa bold). These also lowered the levels of chlorophyll and carotenoids in the emerging leaves during seedling growth. The inhibitory effect was correlated with the concentration of applied toxin.     

Effect of oestradiol dipropionate and testosterone propionate on protein, RNA and DNA contents and RNase and DNase activity in the liver of the toad (Bufo melanosticus)

A single injection of oestradiol dipropionate increased the HSI and protein, RNA and DNA contents and decreased the RNase and DNase activities of the liver of male and female toads. The minimum effective dose of oestrogen required to induce most of these changes was found to be 1 microgram/g (single injection), but the liver RNA content increased at the dose of 0.5 microgram/g. Oestrogen in a dose of 0.1 microgram/g did not cause any of these changes in male and female toads. Testosterone propionate (0.1, 0.5, 1 or 2 micrograms/g, single injection) was mostly ineffective in these respects, while in male toads higher doses of testosterone (1 and 2 micrograms/g) enhanced the liver RNA content only. The oestrogenic responses occurred earlier in female toads than in males. The liver protein and DNA contents increased from the 3rd day in female and on the 5th day in male toads. The liver RNA reached the higher level from the 2nd day in female and from the 3rd day in male. The RNase and DNase activities were reduced from the 2nd and 3rd day, respectively, in female and on the 5th day in male toads.     

Structure of the black beetle virus genome and its functional implications

The black beetle virus (BBV) is an isometric insect virus whose genome consists of two messenger-active RNA molecules encapsidated in a single virion. The nucleotide sequence of BBV RNA1 (3105 bases) has been determined, and this, together with the sequence of BBV RNA2 (1399 bases) provides the complete primary structure of the BBV genome. The RNA1 sequence encompasses a 5' non-coding region of 38 nucleotides, a coding region for a protein of predicted molecular weight 101,873 (protein A, implicated in viral RNA synthesis) and a 3' proximal region encoding RNA3 (389 bases), a subgenomic messenger RNA made in infected cells but not encapsidated into virions. The RNA3 sequence starts 16 bases inside the coding region of protein A and contains two overlapping open reading frames for proteins of molecular weight 10,760 and 11,633, one of which is believed to be protein B, made in BBV-infected cells. A limited homology exists between the sequences of RNA1 and RNA2. Sequence regions have been identified that provide energetically favorable bonding between RNA2 and RNA1 possibly to facilitate their common encapsidation, and between RNA2 and negative strand RNA1 possibly to regulate the production of RNA3.     

Decrease by cycloheximide of calcium binding and nonesterified fatty acids in rat-intestinal Golgi-enriched membrane fractions

Rat intestinal Golgi-enriched membrane fractions bind more Ca2+ than do basolateral and microvillus-enriched membrane fractions, and this uptake is reduced by vitamin D-deficiency. The effect of the protein synthesis inhibitor, cycloheximide, on this Ca2+ binding was determined in rat fed a normal, vitamin D-sufficient diet. Cycloheximide, 1.5 mg/kg, rapidly reduced protein synthesis (measured by [3H]leucine incorporation) to 12% of control values within 15 min, but Ca2+ binding diminished gradually to 50% of control values by 60 min. Ca2+ transport across gut sacs was also decreased. The reduction in Ca2+ binding was not due to an alteration in vesicle morphology or to a direct effect of cycloheximide. Nonesterified (free) fatty acids, the probable binding sites for Ca2+ in these membrane fractions, were reduced by cycloheximide to 48% of control values by 60 min. There was no significant change in total lipid phosphate. Cycloheximide may affect the synthesis of proteins necessary for the presence of nonesterified fatty acids in these Golgi membranes.     

Sweat gland density and response during high-intensity exercise in athletes with spinal cord injuries

Sweat production is crucial for thermoregulation. However, sweating can be problematic for individuals with spinal cord injuries (SCI), as they display a blunting of sudomotor and vasomotor responses below the level of the injury. Sweat gland density and eccrine gland metabolism in SCI are not well understood. Consequently, this study examined sweat lactate (S-LA) (reflective of sweat gland metabolism), active sweat gland density (SGD), and sweat output per gland (S/G) in 7 SCI athletes and 8 able-bodied (AB) controls matched for arm ergometry VO₂peak. A sweat collection device was positioned on the upper scapular and medial calf of each subject just prior to the beginning of the trial, with iodine sweat gland density patches positioned on the upper scapular and medial calf. Participants were tested on a ramp protocol (7 min per stage, 20 W increase per stage) in a common exercise environment (21±1°C, 45-65% relative humidity). An independent t-test revealed lower (p<0.05) SGD (upper scapular) for SCI (22.3 ±14.8 glands · cm⁻²) vs. AB. (41.0 ± 8.1 glands · cm⁻²). However, there was no significant difference for S/G between groups. S-LA was significantly greater (p<0.05) during the second exercise stage for SCI (11.5±10.9 mmol · l⁻¹) vs. AB (26.8±11.07 mmol · l⁻¹). These findings suggest that SCI athletes had less active sweat glands compared to the AB group, but the sweat response was similar (SLA, S/G) between AB and SCI athletes. The results suggest similar interglandular metabolic activity irrespective of overall sweat rate.