Prediction of the halothane (Hal) genotypes of pigs by deducing Hal, Phi, Po2, Pgd haplotypes of parents and offspring: results from a large-scale practice in Swedish breeds

Results from a large-scale study, comprising 75 different breeding herds, are reported on predicting the halothane ( Hal ) genotypes of individual pigs by making use of the known close linkage between Hal and three C blood marker loci ( Phi, Po2, Pgd ). The parents haplotypes (involving Hal and marker loci) were determined from the HAL phenotypes (halothane test results) and marker loci phenotypes of their offspring in the first one or two litters studied. In subsequent litters of the Hal -marker loci haplotyped parents, the offspring's expected Hal genotypes could be predicted on the basis of the marker loci haplotypes inherited by them. By comparing the expected and observed HAL phenotypes of offspring in subsequent litters, the predicted Hal genotype was found to be correct in 90–95 % of the 4000 offspring (from Nn × Nn and Nn × nn matings) of Swedish Landrace and Yorkshire breeds studied.
The order of the three marker loci was confirmed as Phi-Po2-Pgd but the position of Hal with regards to Phi could not be resolved. The recombination frequencies between the most distant loci in this region, viz. Hal-Pgd and Phi-Pgd , were estimated to be 3–4.5 % and 4–6 % , respectively. The easy and rapid electrophoretic techniques described in the study to phenotype PHI, PO2, PGD, also allowed phe-notyping of six other polymorphic protein systems on the same gels. Thus Hal genotyping and effective parentage control can be conducted simultaneously.     

The use of carotenoids and oxonol VI as probes for membrane potential in proteoliposomes

Carotenoids present in lipids extracted from the cyanobacterium Synechococcus 6716 indicate trans-membrane potential in proteoliposomes reconstituted from these lipids and the ATPase complex isolated from the same organism. A carotenoid absorbance band shift to a longer wavelength is obtained with valinomycin-induced potassium ion diffusion potentials, irrespective of the polarity of the potassium gradient. In contrast to this, the (externally added) probe oxonol VI only shows an absorbance band shift when the external potassium ion concentration is higher than the internal one. In liposomes without ATPase complex, no carotenoid absorbance band shifts were observed.     

Heat exchanges in wet suits

Flow of water under foam neoprene wet suits could halve insulation that the suits provided, even at rest in cold water. On the trunk conductance of this flow was approximately 6.6 at rest and 11.4 W . m-2 . C-1 exercising; on the limbs, it was only 3.4 at rest and 5.8 W . m-2 . degrees C-1 exercising; but during vasoconstriction in the cold, skin temperatures on distal parts of limbs were lower than were those of the trunk, allowing adequate metabolic responses. In warm water, minor postural changes and movement made flow under suits much higher, approximately 60 on trunk and 30 W . m-2 . degrees C-1 on limbs, both at rest and at work. These changes in flow allowed for a wide range of water temperatures at which people could stabilize body temperature in any given suit, neither overheating when exercising nor cooling below 35 degrees C when still. Even thin people with 4- or 7- mm suits covering the whole body could stabilize their body temperatures in water near 10 degrees C in spite of cold vasodilatation. Equations to predict limits of water temperature for stability with various suits and fat thicknesses are given.     

Increase of sialyltransferase activity in the serum and liver of inflamed rates

Induction of inflammation by turpentine injection caused 1.5–2-fold increase of both sialy- and galactosyltransferase activity in liver homogenates. The effect was apparent after 12 h turpentine treatment. Serum sialytransferase activity started to increase in the inflamed rats after 18 h, reaching a maximum of 4-fold at 48 h. In contrast, galactosyltransferase activity in serum showed no significant increase. The coordinated and temporal increase of sialytransferase activity in liver and serum suggest involvement of a specific mechanism for the preferential release of this enzyme into serum.     

Estimation of population parameters and their application to the development of fishery management models in two African rivers

The dynamics of fish populations in two African rivers are being investigated with a view to developing fishery management models for tropical non-floodplain rivers. Preliminary work was carried out in the Rufiji River, East Africa, to establish growth and mortality rates along with L _∞ and K for six species in a river where fishing mortality is zero. These parameters, derived from scale-reading and length frequency analysis, also allowed the development of phased management plans for the fishery resulting from impoundment.
A subsequent investigation has begun on a West African river, the Taia in Sierra Leone, to pursue observations over four seasons, two of which are now complete. A systematic daily sampling programme is being carried out of the whole community, to accumulate similar but more extensive data to those obtained previously. In the Taia, however, fishing mortality must also be estimated from catch surveys, and analysis is carried out using the recently developed ELEFAN programs which can be compared with results obtained by other methods such as scale-reading.     

The RAINFOR database: monitoring forest biomass and dynamics

Problem: Data from over 100 permanent sample plots which have been studied for 10–20 years need a suitable system for storage which allows simple data manipulation and retrieval for analysis. Methods: A relational database linking tree records, taxonomic nomenclature and corresponding environmental data has been built in MS Access as part of the RAINFOR project. Conclusion: The database allows flexible and long‐term use of a large amount of data: more than 100 tree plots across Amazonia, incorporating over 80 000 records of individual trees and over 300 000 total records of tree diameter measurements from successive censuses. The database is designed to enable linkages to existing soil, floristic or plant‐trait databases. This database will be a useful tool for exploring the impact of environmental factors on forest structure and dynamics at local to continental scales, and long term changes in forest ecology. As an early example of its potential, we explore the impact of different methodological assumptions on estimates of tropical forest biomass and carbon storage.