Sex differences in relationships between habitat use and reproductive performance in Soay sheep (Ovis aries)

The role of habitat use in generating individual variation in fitness has rarely been examined empirically in natural populations of long‐lived mammals, particularly for both sexes simultaneously. This is the case despite the increase in studies attempting to understand evolutionary change in such populations. Using data from the St. Kilda Soay sheep population, we quantified the association between lifetime reproductive performance (lifetime breeding and reproductive success) and the proportion of the home range covered by a key grass species, H. lanatus, for 490 females and 304 males. Increased H. lanatus cover was associated only with increased female lifetime reproductive success, but increased lifetime breeding success for both sexes, arising through increased male longevity and increased female fecundity. This work suggests that improved understanding of the causes and consequences of fitness differences will likely require us to better account for habitat‐derived individual variation, and to do so for the sexes appropriately.     

Influence of soil hydric parameters on the winter cold hardiness of a burrowing beetle, Leptinotarsa decemlineata (Say)

This investigation examined the influence of soil moisture and associated parameters on the cold hardiness of the Colorado potato beetle (Leptinotarsa decemlineata Say), a temperate-zone species that overwinters in terrestrial burrows. The body mass and water content of adult beetles kept in sand at 4 °C varied over a 16-week period of diapause according to the substratum's moisture content. Changes in body water content, in turn, influenced the crystallization temperature (range −3.3 to −18.4 °C; n = 417), indicating that environmental moisture indirectly determined supercooling capacity, a measure of physiological cold hardiness. Beetles held in dry sand readily tolerated a 24-h exposure to temperatures ranging from 0° to −5 °C, but those chilled in sand containing as little as 1.7% water (dry mass) had elevated mortality. Thus, burrowing in dry soils not only promotes supercooling via its effect on water balance, but may also inhibit inoculative freezing. Mortality of beetles exposed to −5 °C for 24 h was lower in substrates composed of sand, clay and/or peat (36–52%) than in pure silica sand (78%) having an identical water content (17.0% dry mass). In addition to moisture, the texture, structure, water potential, and other physico-chemical attributes of soil may strongly influence the cold hardiness and overwintering survival of burrowing insects. Accepted: 10 September 1996     

Integrated Delivery of Antiretroviral Treatment and Pre-exposure Prophylaxis to HIV-1–Serodiscordant Couples: A Prospective Implementation Study in Kenya and Uganda

BackgroundAntiretroviral-based interventions for HIV-1 prevention, including antiretroviral therapy (ART) to reduce the infectiousness of HIV-1 infected persons and pre-exposure prophylaxis (PrEP) to reduce the susceptibility of HIV-1 uninfected persons, showed high efficacy for HIV-1 protection in randomized clinical trials. We conducted a prospective implementation study to understand the feasibility and effectiveness of these interventions in delivery settings.ConclusionsIntegrated delivery of time-limited PrEP until sustained ART use in African HIV-1-serodiscordant couples was feasible, demonstrated high uptake and adherence, and resulted in near elimination of HIV-1 transmission, with an observed HIV incidence of <0.5% per year compared to an expected incidence of >5% per year.     

Black students’ experiences of transformation at a previously “white only” South African university: a photovoice study

South African higher education has faced much structural transformation since the dismantling of apartheid, and yet remains a racialized space. Despite a stated commitment to transformation in university policy nationally, lay discourses of transformation are highly contested. In these debates, black students are often represented in stigmatizing ways; which affect students’ self-esteem and academic performance. This paper explores black students’ experiences of transformation at the University of Cape Town (UCT), a previously “white only” university, based on the results of a photovoice project. The data analysed are drawn from focus groups, personal reflections, photographs and written stories exploring their experiences at UCT. The findings suggest that there is a failure of transformation at UCT, characterized by the dominance of whiteness in the institution. The paper also discusses how many students internalize the negative stereotypes they encounter whilst others use coping mechanisms and strategies to resist the discourse of black inferiority.     

Effects of in utero odorant exposure on neuroanatomical development of the olfactory bulb and odour preferences

Human babies and other young mammals prefer food odours and flavours of their mother's diet during pregnancy as well as their mother's individually distinctive odour. Newborn mice also prefer the individual odours of more closely related--even unfamiliar--lactating females. If exposure to in utero odorants-which include metabolites from the mother's diet and the foetus's genetically determined individual odour-helps shape the neuroanatomical development of the olfactory bulb, this could influence the perception of such biologically important odours that are preferred after birth. We exposed gene-targeted mice during gestation and nursing to odorants that activate GFP-tagged olfactory receptors (ORs) and then measured the effects on the size of tagged glomeruli in the olfactory bulb where axons from olfactory sensory neurons (OSNs) coalesce by OR type. We found significantly larger tagged glomeruli in mice exposed to these activating odorants in amniotic fluid, and later in mother's milk, as well as significant preferences for the activating odour. Larger glomeruli comprising OSNs that respond to consistently encountered odorants should enhance detection and discrimination of these subsequently preferred odours, which in nature would facilitate selection of palatable foods and kin recognition, through similarities in individual odours of relatives.     

Rad52 and Ku bind to different DNA structures produced early in double-strand break repair

DNA double-strand breaks are repaired by one of two main pathways, non-homologous end joining or homologous recombination. A competition for binding to DNA ends by Ku and Rad52, proteins required for non-homologous end joining and homologous recombination, respectively, has been proposed to determine the choice of repair pathway. In order to test this idea directly, we compared Ku and human Rad52 binding to different DNA substrates. How ever, we found no evidence that these proteins would compete for binding to the same broken DNA ends. Ku bound preferentially to DNA with free ends. Under the same conditions, Rad52 did not bind preferentially to DNA ends. Using a series of defined substrates we showed that it is single-stranded DNA and not DNA ends that were preferentially bound by Rad52. In addition, Rad52 aggregated DNA, bringing different single-stranded DNAs in close proximity. This activity was independent of the presence of DNA ends and of the ability of the single-stranded sequences to form extensive base pairs. Based on these DNA binding characteristics it is unlikely that Rad52 and Ku compete as ‘gatekeepers’ of different DNA double-strand break repair pathways. Rather, they interact with different DNA substrates produced early in DNA double-strand break repair.     

Glycation in diabetic nephropathy

The kidney is an extremely complex organ with broad ranging functions in the body, including but not restricted to waste excretion, ion and water balance, maintenance of blood pressure, glucose homeostasis, generation of erythropoietin and activation of vitamin D. With diabetes, many of these integral processes are interrupted via a combination of haemodynamic and metabolic changes including increases in the accumulation of proteins modified by advanced glycation, known as advanced glycation end products (AGEs). Indeed, hyperglycaemia and the redox imbalances seen with diabetes are each independent accelerants for the production of AGEs, which synergistically combine in this disorder. In addition, as kidney function declines, characterised by a loss of glomerular filtration, the excretion of AGEs is decreased, possibly exacerbating renal injury by further elevating the body’s tissue and circulating AGE pool. Therefore, it has become apparent that decreasing the accumulation of AGEs or interrupting their downstream effects on the kidney, are desirable therapeutic targets for the treatment of diabetic renal disease.     

Host/vector interactions which affect the viability of recombinant phage lambda clones

A class of recombinant phage lambda clones are recovered from human genomic libraries on Escherichia coli recB21 recC22 sbcB15 cells, which fail to form plaques on wild-type cells. We report experiments which address the mechanism of this inhibition. The introduction of the recombination-stimulating sequence chi into one such clone allows growth of this phage on Rec+ cells. In addition, the insertion of lambda gam+ gene into a rec+-inhibited clone results in the ability of the phage to form plaques on wild-type cells. Since lambda Gam protein is an inhibitor of host RecBC enzyme, we tested a collection of such phage for growth on a variety of hosts altered in RecBC function. Host permissiveness correlated with the inactivation of the RecBC nucleolytic activities and not with the recombinational activities. These observations suggest that the inserted DNA sequences of these phage limit the production of packageable chromosomes. This conclusion is easily reconciled with our current knowledge of the interaction of the host recombination systems with lambda replication and encapsidation. Based on these experiments we have constructed strains, both recombination-proficient and recombination-deficient, which serve as improved hosts for the recovery of genomic sequences which are otherwise inhibitory to the growth of phage lambda.     

A survey of the hybridisation status of Cervus deer species on the island of Ireland

Red deer (Cervus elaphus) did not recolonise Ireland after the last glaciation, but the population in Co. Kerry is descended from an ancient (c. 5000 BP) introduction and merits conservation. During the mid-19th century exotic species including North American wapiti (C. canadensis) and Japanese sika deer (C. nippon nippon) were introduced to Ireland, mainly via Powerscourt Park, Co. Wicklow. While wapiti failed to establish, sika thrived, dispersed within Co. Wicklow and were translocated to other sites throughout Ireland. Red deer and sika are known to have hybridised in Ireland, particularly in Co. Wicklow, but an extensive survey with a large, highly diagnostic marker panel is required to assess the threat hybridisation potentially poses to the Co. Kerry red deer population. Here, 374 individuals were genotyped at a panel of 22 microsatellites and at a single mtDNA marker that are highly diagnostic for red deer and Japanese sika. The microsatellites are also moderately diagnostic for red deer and wapiti. Wapiti introgression was very low [trace evidence in 2 (0.53 %) individuals]. Despite long-standing sympatry of red deer and sika in the area, no red deer-sika hybrids were detected in Co. Kerry suggesting strong assortative mating by both species in this area. However, 80/197 (41 %) of deer sampled in Co. Wicklow and 7/15 (47 %) of deer sampled in Co. Cork were red-sika hybrids. Given their proximity and that hybrids are less likely to mate assortatively than pure individuals, the Co. Cork hybrids pose a threat to the Co. Kerry red deer.     

Molecular docking analysis of beta-catenin with compounds derived from Lycopersicon esculentum

Beta-catenin is linked with colorectal cancer (CRC). Therefore, it is of interest to design and develop novel compounds to combat CRC. Hence, we document compounds (chlorogenic acid, gallic acid, protocatechuic acid, quercetin and vanillic acid) from Lycopersicon esculentum with optimal binding features for further consideration.