John S. Terblanche

Bio: John S. Terblanche is an academic researcher from Stellenbosch University. The author has contributed to research in topics: Population & Sclerotherapy. The author has an hindex of 64, co-authored 373 publications receiving 14855 citations. Previous affiliations of John S. Terblanche include Groote Schuur Hospital & University of Cape Town.

Physiological Diversity in Insects: Ecological and Evolutionary Contexts.

Abstract: Publisher Summary This chapter discusses the modern ecological and evolutionary contexts of the evolutionary physiology in insects and provides a survey of sources of environmental variability and their effects on insect populations. The chapter explores environmental variation and the various ways in which it may be quantified. Some environmental variables are relatively simple and straightforward, both to measure and to control, whereas others pose substantially greater problems from both perspectives. Even variables that are seemingly easy to measure might act in ways that are difficult to identify. The chapter examines insect responses to the thermal environment over a variety of spatial and temporal scales, focusing on recent developments in the field. The importance of water availability for insect survival and the determination of distribution and abundance patterns have been widely demonstrated. The chapter considers the question of what lessons insect evolutionary physiologists might have to offer ecology and conservation biology. In particular, how evolutionary physiology can offer ecologists a set of useful general rules in some cases and can unveil the nature of local contingency in others.

Insect thermal tolerance: what is the role of ontogeny, ageing and senescence?

Abstract: Temperature has dramatic evolutionary fitness consequences and is therefore a major factor determining the geographic distribution and abundance of ectotherms. However, the role that age might have on insect thermal tolerance is often overlooked in studies of behaviour, ecology, physiology and evolutionary biology. Here, we review the evidence for ontogenetic and ageing effects on traits of high- and low-temperature tolerance in insects and show that these effects are typically pronounced for most taxa in which data are available. We therefore argue that basal thermal tolerance and acclimation responses (i.e. phenotypic plasticity) are strongly influenced by age and/or ontogeny and may confound studies of temperature responses if unaccounted for. We outline three alternative hypotheses which can be distinguished to propose why development affects thermal tolerance in insects. At present no studies have been undertaken to directly address these options. The implications of these age-related changes in thermal biology are discussed and, most significantly, suggest that the temperature tolerance of insects should be defined within the age-demographics of a particular population or species. Although we conclude that age is a source of variation that should be carefully controlled for in thermal biology, we also suggest that it can be used as a valuable tool for testing evolutionary theories of ageing and the cellular and genetic basis of thermal tolerance.

Critical thermal limits depend on methodological context

Abstract: A full-factorial study of the effects of rates of temperature change and start temperatures was undertaken for both upper and lower critical thermal limits (CTLs) using the tsetse fly, Glossina pallidipes . Results show that rates of temperature change and start temperatures have highly significant effects on CTLs, although the duration of the experiment also has a major effect. Contrary to a widely held expectation, slower rates of temperature change (i.e. longer experimental duration) resulted in poorer thermal tolerance at both high and low temperatures. Thus, across treatments, a negative relationship existed between duration and upper CTL while a positive relationship existed between duration and lower CTL. Most importantly, for predicting tsetse distribution, G. pallidipes suffer loss of function at less severe temperatures under the most ecologically relevant experimental conditions for upper (0.06°C min−1; 35°C start temperature) and lower CTL (0.06°C min−1; 24°C start temperature). This suggests that the functional thermal range of G. pallidipes in the wild may be much narrower than previously suspected, approximately 20–40°C, and highlights their sensitivity to even moderate temperature variation. These effects are explained by limited plasticity of CTLs in this species over short time scales. The results of the present study have broad implications for understanding temperature tolerance in these and other terrestrial arthropods.

A new look at the arterial supply of the bile duct in man and its surgical implications.

Abstract: The blood supply of the human bile duct has been re-evaluated using high resolution resin casts prepared from 24 fresh human cadavers. The refined technique used yielded casts of all vessels, including capillaries, and produced a clear picture of the blood supply of the human bile duct for the first time. The arterial supply of the supraduodenal duct was shown to be axial, with the main vessels, which have been named the 3 o'clock and 9 o'clock arteries, running along the lateral borders. The retroportal artery, which has not been described by previous workers, was present in all complete casts and was a major source of the axial blood supply to the supraduodenal duct in 32 per cent of them. The major importance of this new knowledge of bile duct blood supply may well lie in the understanding of the aetiology of postoperative bile duct strictures and in their prevention. An explanation is proposed for the long strictures sometimes seen after minimal surgical trauma to the bile duct, based on damage to the small vessels supplying the duct; guidelines to prevent such damage are presented. Ischaemia of the bile duct may also explain some of the biliary problems that have followed human liver transplantation and other procedures involving biliary anastomosis, such as Whipple's operation.

Human biochemical genetics

Abstract: So far in this course we have dealt entirely with the evolution of characters that are controlled by simple Mendelian inheritance at a single locus. There are notes on the course website about gametic disequilibrium and how allele frequencies change at two loci simultaneously, but we didn’t discuss them. In every example we’ve considered we’ve imagined that we could understand something about evolution by examining the evolution of a single gene. That’s the domain of classical population genetics. For the next few weeks we’re going to be exploring a field that’s actually older than classical population genetics, although the approach we’ll be taking to it involves the use of population genetic machinery. If you know a little about the history of evolutionary biology, you may know that after the rediscovery of Mendel’s work in 1900 there was a heated debate between the “biometricians” (e.g., Galton and Pearson) and the “Mendelians” (e.g., de Vries, Correns, Bateson, and Morgan). Biometricians asserted that the really important variation in evolution didn’t follow Mendelian rules. Height, weight, skin color, and similar traits seemed to

“Bioinformatics” 특집을 내면서

Abstract: BIOE 402. Medical Technology Assessment. 2 or 3 hours. Bioentrepreneur course. Assessment of medical technology in the context of commercialization. Objectives, competition, market share, funding, pricing, manufacturing, growth, and intellectual property; many issues unique to biomedical products. Course Information: 2 undergraduate hours. 3 graduate hours. Prerequisite(s): Junior standing or above and consent of the instructor.

Climate Change 2007: The Physical Science Basis.

Abstract: Cause, conseguenze e strategie di mitigazione Proponiamo il primo di una serie di articoli in cui affronteremo l’attuale problema dei mutamenti climatici. Presentiamo il documento redatto, votato e pubblicato dall’Ipcc - Comitato intergovernativo sui cambiamenti climatici - che illustra la sintesi delle ricerche svolte su questo tema rilevante.