Some aspects of the biology of Malaysian riverine cyprinids

Four indigenous riverine carps, namely Leptobarbus hoeveni, Tor tambroides, Puntius daruphani and Puntius bulu, currently command a good market price in Malaysia. The potential of these species for culture was assessed by both field and experimental studies. Basic information essential for future breeding programmes of these species was obtained. The findings suggest that at least some of these species could prove to be useful new species for future aquaculture programmes.     

A comparison of serum neutralisation, immunofluorescence and immunoperoxidase tests for the detection of antibodies to chicken anaemia agent

A comparison was made of the serum neutralisation, immunofluorescent antibody and immunoperoxidase tests for the detection of antibodies to chicken anaemia agent. Serum samples from groups of chicks with and without maternally derived antibody to the agent were tested and the response of chicks after inoculation with the agent was also measured. The serum neutralisation test was reliable and sensitive, but expensive and could take up to three weeks to obtain a result. The immunofluorescent antibody test was cheaper and required only one day to obtain a result, but it was not as sensitive in detecting low levels of antibody to the chicken anaemia agent. The immunoperoxidase test was also cheaper but took two days to obtain a result and required one more manipulation than the immunofluorescence test. It was comparable to the serum neutralisation test in its ability to detect low levels of antibody.     

Nucleotide sequence of yellow fever virus: implications for flavivirus gene expression and evolution

The sequence of the entire RNA genome of the type flavivirus, yellow fever virus, has been obtained. Inspection of this sequence reveals a single long open reading frame of 10,233 nucleotides, which could encode a polypeptide of 3411 amino acids. The structural proteins are found within the amino-terminal 780 residues of this polyprotein; the remainder of the open reading frame consists of nonstructural viral polypeptides. This genome organization implies that mature viral proteins are produced by posttranslational cleavage of a polyprotein precursor and has implications for flavivirus RNA replication and for the evolutionary relation of this virus family to other RNA viruses.     

Genes for beta chain of human T-cell antigen receptor map to regions of chromosomal rearrangement in T cells

The T-cell antigen receptor is a cell-surface molecule that participates in the immune response. In the present experiments the genes encoding the beta chain of the T-cell receptor were found to reside on the long arm of human chromosome 7 at or near band q32. Related sequences were found on the short arm of chromosome 7 in bands p15-21 in some experiments. Chromosomal rearrangements in T-cells from normal individuals and patients with ataxia telangiectasia have previously been observed at and near these map assignments for the beta-chain genes.     

Early-age feed restriction affects viability and gene expression of satellite cells isolated from the gastrocnemius muscle of broiler chicks

Background: Muscle growth depends on the fusion of proliferate satellite cells to existing myofibers. We reported previously that 0-14 day intermittent feeding led to persistent retardation in myofiber hypertrophy. However, how satellite cells respond to such nutritional insult has not been adequately elucidated. Results: One-day-old broiler chicks were allocated to control (Con, ad libitum feeding), intermittent feeding (IF, feed provided on alternate days) and re-feeding (RF, 2 days ad libitum feeding after 12 days of intermittent feeding) groups. Chickens were killed on Day 15 and satellite cells were isolated. When cultured, satellite cells from the IF group demonstrated significant retardation in proliferation and differentiation potential, while RF partly restored the proliferation rate and differentiation potential of the satellite cells. Significant up-regulation of insulin like growth factor I receptor (IGF-IR) (P<0.05) and thyroid hormone receptor α (TRα) (P<0.05), and down-regulation of growth hormone receptor (GHR) (P<0.01) and IGF-I (P<0.01) mRNA expression was observed in freshly isolated IF satellite cells when compared with Con cells. In RF cells, the mRNA expression of IGF-I was higher (P<0.05) and of TRα was lower (P<0.01) than in IF cells, suggesting that RF restored the mRNA expression of TRα and IGF-I, but not of GHR and IGF-IR. The Bax/Bcl-2 ratio tended to increase in the IF group, which was reversed in the RF group (P<0.05), indicating that RF reduced the pro-apoptotic influence of IF. Moreover, no significant effect of T 3 was detected on cell survival in IF cells compared with Con (P<0.001) or RF (P<0.05) cells. Conclusions: These data suggest that early-age feed restriction inhibits the proliferation and differentiation of satellite cells, induces changes in mRNA expression of the GH/IGF-I and thyroid hormone receptors in satellite cells, as well as blunted sensitivity of satellite cells to T3 , and that RF partially reverses these effects. Thus, a moderate nutritional strategy for feed restriction should be chosen in early chick rearing systems.     

Temporal Secretory Patterns of Growth Hormone in the Danish Broiler Lines Selected for High Body Weight or for Improved Food Efficiency

Abstract

Plasma growth hormone (GH) secretory profiles of 8-week-old male and female broiler chickens selected for high body weight at 42 days of age (GL line) or for improved food efficiency between 18 and 39 days of age (FCR line) were compared. A pulsatile GH secretory pattern was still present for all the 8-week-old chickens examined. Overall mean GH levels, and to a lesser extent GH baseline and GH amplitude values, were higher for FCR chickens compared with GL chickens. Mean GH concentrations, baseline and amplitudes were slightly, but not significantly, superior in males. Length and frequency of pulses were not influenced by line or sex. In view of the current knowledge on age- and sex-related changes in pulsatile GH secretion, it is argued that the line and sex differences would have been more pronounced in younger chickens. Based on this, the hypothesis that the amplitude of the pulsatile GH release is related to protein conversion efficiency and protein deposition rather than to average body weight gain is corroborated.     

An approach to GIS-based multiple criteria decision analysis that integrates exploration and evaluation phases: Case study in a forest-dominated landscape

The increasing importance and complexity of land and natural resource management are creating a need for ecosystem-based management (EBM). Multiple criteria decision analysis (MCDA) combined with geographic information systems (GIS) can integrate factors related to the triple bottom line of ecological, economic, and social perspectives required by EBM. However, GIS-based MCDA is limited in this role because (i) it rarely integrates or encourages an exploration phase in preparation for structured evaluation and (ii) inexperienced users may find MCDA methods and GIS software difficult to use. This paper presents a novel approach for (i) supporting an exploration phase to help structure a problem and (ii) integrating the exploration and evaluation phases in an easy-to-use software system. The approach was validated through a land-management case study in a forest-dominated landscape with a variety of stakeholders. Case-study participants used the approach to rate areas within a timber harvest plan based on their potential for conflict with conservation values. The case-study decision analysis determined that between 1.3% and 6.6% of the harvest plan area had a conservation rating of 0.30 or higher on a scale of 0–1. The system was made available to the forest industry and other stakeholders to support harvest plan adjustments, demonstrating how such tools can be used to improve and integrate our knowledge of forest ecology and management. Assessment of participant feedback reveals that an exploration phase is effective in helping understand a problem and prepare for multiple criteria evaluation (MCE).