Some aspects of the biology of the red bass, Lutjanus bohar (Forsskal), from the Tigak Islands, Papua New Guinea

The growth rate, food, reproduction and mortality rates of the red bass, Lutjanus bohar , are described for fish associated with coral reefs in the Tigak Islands of Papua New Guinea. Spawning intensity by month was investigated by examination of gonad maturation stages. The length–at–maturity of female L. bohar was estimated from the relationship between changes in gonad index with increasing size. Female fish matured at about 45–0 cm fork length. The Petersen method was used to obtain age–at–length data from length frequency data of L. bohar captured by hook–and–line fishing. The growth of L. bohar was described by a von Bertalanffy growth curve with the parameters AT=0.27 and L_∞ = 81.7 cm. There was a positive correlation between water depth (D) and the length of L. bohar (L) that was described by L = 318–8+ 3.050 D . The mortality rates ( Z ) of L. bohar from shallow (≤30m) and deep (≤80m) water were estimated from length converted catch curves and were 1–181 and 0–64 respectively. The high Z value for the shallow water population of L. bohar was ascribed to the migration of larger specimens into deeper water. The deep water population of L. bohar remains unfished and the estimate of Z was believed to be equivalent to the natural mortality rate ( M ). An empirical method of calculating M gave an estimate of 0.59. Lutjanus bohar is a carnivorous piscivore that feeds throughout the water column.     

Effect of neurotensin on pancreatic function in man

The effect of neurotensin on submaximally-stimulated hepatobiliary and pancreatic secretion was studied in 6 healthy subjects. An intravenous infusion of neurotensin 1.4 ± 0.3 pmol/kg/min, designed to reproduce plasma neurotensin immunoreactivity levels within the physiological range, produced a significant increase in pancreatic bicarbonate output. Plasma concentrations of pancreatic polypeptide rose by 83 ± 16 pmol/l and were associated with a small reduction in trypsin, but no significant change in bilirubin outputs.     

Failure of intracerebral BCG cell wall preparation to prevent glioma induction by avian sarcoma virus in rats

Summary Five-day-old Fischer 344 rats were inoculated intracerebrally with BCG cell walls attached to oil (BCG-CW) or with oil emulsion alone. Doses of BCG-CW of 40 g in 0.01 ml, 200 g in 0.05 ml, and 400 g in 0.1 ml were used, with similar volumes of oil emulsion for comparison. Twentyfive days later hydrocephalus, intracerebral granulomas, and arachnoid granulomas were found at autopsy. The frequency and severity of these abnormalities were related to the presence of BCG-CW in the inoculum and the dose administered. There were minimal abnormalities with 40 g BCG-CW.Two microliters of Avian sarcoma virus (ASV) suspension was inoculated intracerebrally into 5-day-old rats to induce intracerebral gliomas. One hour later 40 g BCG-CW in 0.01 ml, 80 g BCG-CW in 0.02 ml, or similar volumes of oil emulsion alone were inoculated intracerebrally in the region of the virus injection site. BCG-CW or oil emulsion alone failed to prevent induction and growth of the ASV-induced brain tumors. Survival curves of the BCG-CW inoculated animals were similar to that obtained for control animals injected with ASV and otherwise untreated. The oil emulsion decreased survival times compared with control animals.     

Effect of Metalaxyl on the incidence and severity of Pearl millet downy mildew disease in Northern Nigeria

Pearl millet downy mildew (DM) incidence, severity and yield losses of two pearl millet varieties (local and improved) due to the disease were determined in the field. Significant differences in the disease incidence and severity were recorded in the plots sown with metalaxyl-treated seeds and those sown with non-treated seeds, indicating the efficacy of the fungicide on the fungus. Yield losses due to non-treatment of seeds with metalaxyl was 40.88 and 45.39% in a local variety and 43.00 and 18.60% in an improved variety in the 2000 and 2001 cropping seasons respectively. Significant differences between plots sown with metalaxyl-treated and those sown with non-treated seeds were obtained for other yield components such as 1000-grains weight, panicle length and weight.     

QTL mapping for two commercial traits in farmed saltwater crocodiles (Crocodylus porosus)

The recent generation of a genetic linkage map for the saltwater crocodile (Crocodylus porosus) has now made it possible to carry out the systematic searches necessary for the identification of quantitative trait loci (QTL) affecting traits of economic, as well as evolutionary, importance in crocodilians. In this study, we conducted genome‐wide scans for two commercially important traits, inventory head length (which is highly correlated with growth rate) and number of scale rows (SR, a skin quality trait), for the existence of QTL in a commercial population of saltwater crocodiles at Darwin Crocodile Farm, Northern Territory, Australia. To account for the uncommonly large difference in sex‐specific recombination rates apparent in the saltwater crocodile, a duel mapping strategy was employed. This strategy employed a sib‐pair analysis to take advantage of our full‐sib pedigree structure, together with a half‐sib analysis to account for, and take advantage of, the large difference in sex‐specific recombination frequencies. Using these approaches, two putative QTL regions were identified for SR on linkage group 1 (LG1) at 36 cM, and on LG12 at 0 cM. The QTL identified in this investigation represent the first for a crocodilian and indeed for any non‐avian member of the Class Reptilia. Mapping of QTL is an important first step towards the identification of genes and causal mutations for commercially important traits and the development of selection tools for implementation in crocodile breeding programmes for the industry.