Human origins in a southern African palaeo-wetland and first migrations.

Anatomically modern humans originated in Africa around 200 thousand years ago (ka)1-4. Although some of the oldest skeletal remains suggest an eastern African origin2, southern Africa is home to contemporary populations that represent the earliest branch of human genetic phylogeny5,6. Here we generate, to our knowledge, the largest resource for the poorly represented and deepest-rooting maternal L0 mitochondrial DNA branch (198 new mitogenomes for a total of 1,217 mitogenomes) from contemporary southern Africans and show the geographical isolation of L0d1'2, L0k and L0g KhoeSan descendants south of the Zambezi river in Africa. By establishing mitogenomic timelines, frequencies and dispersals, we show that the L0 lineage emerged within the residual Makgadikgadi-Okavango palaeo-wetland of southern Africa7, approximately 200 ka (95% confidence interval, 240-165 ka). Genetic divergence points to a sustained 70,000-year-long existence of the L0 lineage before an out-of-homeland northeast-southwest dispersal between 130 and 110 ka. Palaeo-climate proxy and model data suggest that increased humidity opened green corridors, first to the northeast then to the southwest. Subsequent drying of the homeland corresponds to a sustained effective population size (L0k), whereas wet-dry cycles and probable adaptation to marine foraging allowed the southwestern migrants to achieve population growth (L0d1'2), as supported by extensive south-coastal archaeological evidence8-10. Taken together, we propose a southern African origin of anatomically modern humans with sustained homeland occupation before the first migrations of people that appear to have been driven by regional climate changes.

The effects of a small hydropower scheme on the migratory behaviour of Atlantic salmon Salmo salar smolts.

The potential effects of a hydropower scheme on the migratory behaviour of Atlantic salmon Salmo salar smolts was studied on the River Frome, southern England. The potential delay to migration at the intake of the hydropower scheme was assessed, together with the effects of passage through the turbine on the temporal and spatial migration of the fish in the river and estuary. The migratory behaviour of the emigrating S. salar smolts was monitored using miniature acoustic transmitters and an array of acoustic receivers positioned at the hydropower scheme and in the river and estuary. The majority of the smolts bypassed the hydropower scheme with only 8.1% of the fish moving downstream through the turbine. Movement was nocturnal and occurred during elevated river flows. There was no apparent delay at the turbine intake or at the adjacent weir. The subsequent migration of all smolts through the estuary of the River Frome occurred during both day and night and there was a distinct ebb-tide migration through the estuary and into the coastal zone. There was no difference in the rate of migration between smolts that moved through the turbine or over the weir. The detection of smolts during both the freshwater migration and the transition from the freshwater to the marine environments was high (91.8 and 73.3%, respectively). A laboratory investigation on the de-scaling of smolts indicated that removal of 1, 5 and 10% of scales had no significant effect on saltwater survival or the measured physiological parameters (gill Na+ -K+ -ATPase activity, plasma osmolality and chloride concentrations). Smolt passage through the turbine was assessed and resulted in either no damage to the integument or scale loss or between 20 and 80% of total body area of recaptured smolts. It is estimated that 1.53% of the smolt population would suffer significant damage after passage through the turbine. The implications of the hydropower scheme on the population of salmon in the River Frome are discussed.

Genetic Evidence for Contrasting Wetland and Savannah Habitat Specializations in Different Populations of Lions (Panthera leo).

South-central Africa is characterized by an archipelago of wetlands, which has evolved in time and space since at least the Miocene, providing refugia for animal species during Pleistocene arid episodes. Their importance for biodiversity in the region is reflected in the evolution of a variety of specialist mammal and bird species, adapted to exploit these wetland habitats. Populations of lions (Panthera leo) across south-central and east Africa have contrasting signatures of mitochondrial DNA haplotypes and biparental nuclear DNA in wetland and savannah habitats, respectively, pointing to the evolution of distinct habitat preferences. This explains the absence of genetic admixture of populations from the Kalahari savannah of southwest Botswana and the Okavango wetland of northern Botswana, despite separation by only 500 km. We postulate that ancestral lions were wetland specialists and that the savannah lions evolved from populations that were isolated during arid Pleistocene episodes. Expansion of grasslands and the resultant increase in herbivore populations during mesic Pleistocene climatic episodes provided the stimulus for the rapid population expansion and diversification of the highly successful savannah lion specialists. Our model has important implications for lion conservation.

Gastrin receptor pharmacology.

C-terminally amidated gastrins act at cholecystokinin-2 receptors (CCK2R), which are normally expressed by gastric parietal and enterochromaffin-like (ECL) cells and smooth muscle; there is also extensive expression in the CNS where the main endogenous ligand is cholecystokinin. A variety of neoplasms express CCK2R, or splice variants, including neuroendocrine, pancreatic, medullary thyroid and lung cancers. Other products of the gastrin gene (progastrin, the Gly-gastrins) may stimulate cell proliferation but are not CCK2R ligands. Depending on the cell type, stimulation of CCK2R evokes secretion, increases proliferation and cell migration, inhibits apoptosis, and controls the expression of various genes. These effects are mediated by increased intracellular calcium and activation of protein kinase C, MAPkinase and other protein kinase cascades. There has been recent progress in developing CCK2R ligands that can be used for imaging tumours expressing the receptor. New antagonists have also been developed, and there is scope for using these for suppression of gastric acid and for treatment of neuroendocrine and other CCK2R-expressing tumours.

Life-history strategies in salmonids: the role of physiology and its consequences.

Salmonids are some of the most widely studied species of fish worldwide. They span freshwater rivers and lakes to fjords and oceans; they include short- and long-distance anadromous migrants, as well as partially migratory and non-migratory populations; and exhibit both semelparous and iteroparous reproduction. Salmonid life-history strategies represent some of the most diverse on the planet. For this reason, salmonids provide an especially interesting model to study the drivers of these different life-history pathways. Over the past few decades, numerous studies and reviews have been published, although most have focused on ultimate considerations where expected reproductive success of different developmental or life-history strategies are compared. Those that considered proximate causes generally focused on genetics or the environment, with less consideration of physiology. Our objective was therefore to review the existing literature on the role of physiology as a proximate driver for life-history strategies in salmonids. This link is necessary to explore since physiology is at the core of biological processes influencing energy acquisition and allocation. Energy acquisition and allocation processes, in turn, can affect life histories. We find that life-history strategies are driven by a range of physiological processes, ranging from metabolism and nutritional status to endocrinology. Our review revealed that the role of these physiological processes can vary across species and individuals depending on the life-history decision(s) to be made. In addition, while findings sometimes vary by species, results appear to be consistent in species with similar life cycles. We conclude that despite much work having been conducted on the topic, the study of physiology and its role in determining life-history strategies in salmonids remains somewhat unexplored, particularly for char and trout (excluding brown trout) species. Understanding these mechanistic links is necessary if we are to understand adequately how changing environments will impact salmonid populations.

Persistent contaminants in adipose fins of returning adult salmonids to the river Tees (UK).

We report on concentrations of polybrominated diphenylethers (PBDEs), polychlorinated biphenyls (PCBs), dichlorodiphenyldichloroethylene (p,p'-DDE) and hexachlorobenzene (HCB) measured in the adipose fins of returning adult Atlantic salmon (Salmo salar) and sea trout (Salmo trutta) to the river Tees in the Northeast of England. Overall, higher concentrations of these contaminants were found in sea trout samples, where detected congeners reflected the more widely used commercial formulations, in particular for the PBDEs. Our results suggest that these fish could be bioaccumulating persistent organic pollutants via diet during their migratory routes (North Sea and the Norwegian Sea) and, in addition, some level of re-mobilisation of these compounds could still be occurring in the UK eastern coastal areas. The use of adipose fin of returning salmonids could be further developed as a non-lethal approach to assess whether persistent contaminants are being accumulated during the juvenile to adult phase of salmonids originating from UK rivers.

Unintended changes in protein expression revealed by proteomic analysis of seeds from transgenic pea expressing a bean alpha-amylase inhibitor gene.

Seeds of genetically modified (GM) peas (Pisum sativum L.) expressing the gene for alpha-amylase inhibitor-1 (alphaAI1) from the common bean (Phaseolus vulgaris L. cv. Tendergreen) exhibit resistance to the pea weevil (Bruchus pisorum). A proteomic analysis was carried out to compare seeds from GM pea lines expressing the bean alphaAI1 protein and the corresponding alphaAI1-free segregating lines and non-GM parental line to identify unintended alterations to the proteome of GM peas due to the introduction of the gene for alphaAI1. Proteomic analysis showed that in addition to the presence of alphaAI1, 33 other proteins were differentially accumulated in the alphaAI1-expressing GM lines compared with their non-GM parental line and these were grouped into five expression classes. Among these 33 proteins, only three were found to be associated with the expression of alphaAI1 in the GM pea lines. The accumulation of the remaining 30 proteins appears to be associated with Agrobacterium-mediated transformation events. Sixteen proteins were identified after MALDI-TOF-TOF analysis. About 56% of the identified proteins with altered accumulation in the GM pea were storage proteins including legumin, vicilin or convicilin, phaseolin, cupin and valosin-containing protein. Two proteins were uniquely expressed in the alphaAI1-expressing GM lines and one new protein was present in both the alphaAI1-expressing GM lines and their alphaAI1-free segregating lines, suggesting that both transgenesis and transformation events led to demonstrable changes in the proteomes of the GM lines tested.

An Improved Transformation System for Cowpea (Vigna unguiculata L. Walp) via Sonication and a Kanamycin-Geneticin Selection Regime.

An improved cowpea transformation method utilizing Agrobacterium-mediated gene delivery to explants derived from the cotyledonary nodes of imbibed cowpea seed is described. The explants were regenerated following a sonication procedure and a stringent selection comprising alternating regimes of kanamycin and geneticin. The method was reproducible and led to the recovery of independent fertile transgenic plants in the greenhouse at a level of about one per cent of starting explants. A transgene encoding an insecticidal protein from Bacillus thuringiensis was used to demonstrate the efficacy of the system.

Competency standards and educational requirements for specialist breast nurses in Australia.

There is substantial evidence that Specialist Breast Nurses (SBNs) make an important contribution to improved outcomes for women with breast cancer, by providing information and support and promoting continuity of care. However, a recent study has identified significant variation in how the role functions across individual nurses and settings, which is likely to contribute to varied outcomes for women with breast cancer. The project reported in this paper illustrates how a set of competency standards for SBNs were developed by the National Breast Cancer Centre. The competency standards were developed through a review of published literature and consultation with key stakeholders. The resulting SBN Competency Standards reflect the core domains and elements of SBN practice seen as integral to achieving optimal outcomes for women with breast cancer. This project identifies the SBN as a registered nurse who applies advanced knowledge of the health needs, preferences and circumstances of women with breast cancer to optimise the individual's health and well-being at various phases across the continuum of care, including diagnosis, treatment, rehabilitation, follow-up and palliative care. The five core domains of practice identified are: Supportive care; Collaborative care; Coordinated care; Information provision and education; and Clinical leadership. A variety of education programs are currently available for nurses who wish to learn about breast cancer nursing. The majority of stakeholders consulted in this project agreed that a Graduate Diploma level of education is required at minimum in order for an SBN to develop the minimum level of competence required to perform the role. The evidence supports the view that as an advanced role, nurses practising as SBNs require high-quality programs of sufficient depth and scope to achieve the required level of competence.

Whether European eel leptocephali use the Earth's magnetic field to guide their migration remains an open question.

European eels (Anguilla anguilla) migrate between the southwestern Sargasso Sea and the European and Mediterranean coasts. In a recent paper in Current Biology, Naisbett-Jones et al.[1] claim to "provide the first evidence that they [eels] derive positional information from the Earth's magnetic field" and that this information guides their migration. The evidence reported by Naisbett-Jones et al.[1] in support of this conclusion was derived from eels collected in the Severn River (UK), approximately 50 km upstream of the estuary (i.e. not "in the Severn Estuary" as stated by the authors). Eels collected this far into rivers are benthic and fully adapted to freshwater; that is, they are late-stage glass eels (∼ 2 years old), not the pelagic leptocephalus (larval) life stage that actually undertakes the trans-Atlantic migration. The entire interpretive framework for the Naisbett-Jones et al.[1] study rests on the assumption that the behaviour of these late-stage freshwater glass eels, and their responses to magnetic fields, can be used as a proxy for the responses of eel leptocephali. The authors present no evidence in support of this key assumption.

Locations of marine animals revealed by carbon isotopes.

Knowing the distribution of marine animals is central to understanding climatic and other environmental influences on population ecology. This information has proven difficult to gain through capture-based methods biased by capture location. Here we show that marine location can be inferred from animal tissues. As the carbon isotope composition of animal tissues varies with sea surface temperature, marine location can be identified by matching time series of carbon isotopes measured in tissues to sea surface temperature records. Applying this technique to populations of Atlantic salmon (Salmo salar L.) produces isotopically-derived maps of oceanic feeding grounds, consistent with the current understanding of salmon migrations, that additionally reveal geographic segregation in feeding grounds between individual philopatric populations and age-classes. Carbon isotope ratios can be used to identify the location of open ocean feeding grounds for any pelagic animals for which tissue archives and matching records of sea surface temperature are available.

Genetic transformation of cowpea (Vigna unguiculata L.) and stable transmission of the transgenes to progeny.

Cowpeas are nutritious grains that provide the main source of protein, highly digestible energy and vitamins to some of the world's poorest people. The demand for cowpeas is high but yields remain critically low, largely because of insect pests. Cowpea germplasm contains little or no resistance to major insect pests and a gene technology approach to adding insect protection traits is now a high priority. We have adapted features of several legume and other transformation systems and reproducibly obtained transgenic cowpeas that obey Mendelian rules in transmitting the transgene to their progeny. Critical parameters in this transformation system include the choice of cotyledonary nodes from developing or mature seeds as explants and a tissue culture medium devoid of auxins in the early stages, but including the cytokinin BAP at low levels during shoot initiation and elongation. Addition of thiol-compounds during infection and co-culture with Agrobacterium and the choice of the bar gene for selection with phosphinothricin were also important. Transgenic cowpeas that transmit the transgenes to their progeny can be recovered at a rate of one fertile plant per thousand explants. These results pave the way for the introduction of new traits into cowpea and the first genes to be trialled will include those with potential to protect against insect pests.