Maternal vitamin C deficiency during pregnancy persistently impairs hippocampal neurogenesis in offspring of guinea pigs

While having the highest vitamin C (VitC) concentrations in the body, specific functions of VitC in the brain have only recently been acknowledged. We have shown that postnatal VitC deficiency in guinea pigs causes impairment of hippocampal memory function and leads to 30% less neurons. This study investigates how prenatal VitC deficiency affects postnatal hippocampal development and if any such effect can be reversed by postnatal VitC repletion. Eighty pregnant Dunkin Hartley guinea pig dams were randomized into weight stratified groups receiving High (900 mg) or Low (100 mg) VitC per kg diet. Newborn pups (n = 157) were randomized into a total of four postnatal feeding regimens: High/High (Control); High/Low (Depleted), Low/Low (Deficient); and Low/High (Repleted). Proliferation and migration of newborn cells in the dentate gyrus was assessed by BrdU labeling and hippocampal volumes were determined by stereology. Prenatal VitC deficiency resulted in a significant reduction in postnatal hippocampal volume (P<0.001) which was not reversed by postnatal repletion. There was no difference in postnatal cellular proliferation and survival rates in the hippocampus between dietary groups, however, migration of newborn cells into the granular layer of the hippocampus dentate gyrus was significantly reduced in prenatally deficient animals (P<0.01). We conclude that a prenatal VitC deficiency in guinea pigs leads to persistent impairment of postnatal hippocampal development which is not alleviated by postnatal repletion. Our findings place attention on a yet unrecognized consequence of marginal VitC deficiency during pregnancy.

The evolutionary diversification of parrots supports a taxon pulse model with multiple trans-oceanic dispersal events and local radiations

Vicariance is thought to have played a major role in the evolution of modern parrots. However, as the relationships especially of the African taxa remained mostly unresolved, it has been difficult to draw firm conclusions about the roles of dispersal and vicariance. Our analyses using the broadest taxon sampling of old world parrots ever based on 3219 bp of three nuclear genes revealed well-resolved and congruent phylogenetic hypotheses. Agapornis of Africa and Madagascar was found to be the sister group to Loriculus of Australasia and Indo-Malayasia and together they clustered with the Australasian Loriinae, Cyclopsittacini and Melopsittacus. Poicephalus and Psittacus from mainland Africa formed the sister group Of the Neotropical Arini and Coracopsis from Madagascar and adjacent islands may be the closest relative of Psittrichas from New Guinea. These biogeographic relationships are best explained by independent colonization of the African continent via trans-oceanic dispersal from Australasia and Antarctica in the Paleogene following what may have been vicariance events in the late Cretaceous and/or early Paleogene. Our data support a taxon pulse model for the diversification of parrots whereby trans-oceanic dispersal played a more important role than previously thought and was the prerequisite for range expansion into new continents. (C) 2009 Elsevier Inc. All rights reserved

Polycyclic aromatic compounds (PAHs and oxygenated PAHs) and trace metals in fish species from Ghana (West Africa): Bioaccumulation and health risk assessment

We report the concentrations of 28 PAHs, 15 oxygenated PAHs (OPAHs) and 11 trace metals/metalloids (As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Se, and Zn) in muscle and gut + gill tissues of demersal fishes (Drapane africana, Cynoglossus senegalensis and Pomadasys peroteti) from three locations along the coast of the Gulf of Guinea (Ghana). The concentrations of ∑ 28PAHs in muscle tissues averaged 192 ng g− 1 dw (range: 71–481 ng g− 1 dw) and were not statistically different between locations. The concentrations of ∑ 28 PAHs were higher in guts + gills than in muscles. The PAH composition pattern was dominated by low molecular weight compounds (naphthalene, alkyl-naphthalenes and phenanthrene). All fish tissues had benzo[a]pyrene concentrations lower than the EU limit for food safety. Excess cancer risk from consumption of some fish was higher than the guideline value of 1 × 10− 6. The concentrations of ∑ 15 OPAHs in fish muscles averaged 422 ng g− 1 dw (range: 28–1715 ng g− 1dw). The ∑ 15 OPAHs/∑ 16 US-EPA PAHs concentration ratio was > 1 in 68% of the fish muscles and 100% of guts + gills. The log-transformed concentrations of PAHs and OPAHs in muscles, guts + gills were significantly (p < 0.05) correlated with their octanol–water partitioning coefficients, strongly suggesting that equilibrium partitioning from water/sediment into fish tissue was the main mechanism of bioaccumulation. The trace metal concentrations in the fish tissues were in the medium range when compared to fish from other parts of the world. The concentrations of some trace metals (Cd, Cu, Fe, Mn, Zn) were higher in guts + gills than in muscle tissues. The target hazard quotients for metals were < 1 and did not indicate a danger to the local population. We conclude that the health risk arising from the consumption of the studied fish (due to their PAHs and trace metals content) is minimal.

Ebola virus disease outbreak in Nigeria: Transmission dynamics and rapid control.

International air travel has already spread Ebola virus disease (EVD) to major cities as part of the unprecedented epidemic that started in Guinea in December 2013. An infected airline passenger arrived in Nigeria on July 20, 2014 and caused an outbreak in Lagos and then Port Harcourt. After a total of 20 reported cases, including 8 deaths, Nigeria was declared EVD free on October 20, 2014. We quantified the impact of early control measures in preventing further spread of EVD in Nigeria and calculated the risk that a single undetected case will cause a new outbreak. We fitted an EVD transmission model to data from the outbreak in Nigeria and estimated the reproduction number of the index case at 9.0 (95% confidence interval [CI]: 5.2-15.6). We also found that the net reproduction number fell below unity 15 days (95% CI: 11-21 days) after the arrival of the index case. Hence, our study illustrates the time window for successful containment of EVD outbreaks caused by infected air travelers.

A 2-D guinea pig lung proteome map

Guinea pigs represent an important model for a number of infectious and non-infectious pulmonary diseases. The guinea pig genome has recently been sequenced to full coverage, opening up new research avenues using genomics, transcriptomics and proteomics techniques in this species. In order to further annotate the guinea pig genome and to facilitate future pulmonary proteomics in this species we constructed a 2-D guinea pig proteome map including 486 protein identifications and post translational modifications (PTMs). The map has been up-loaded to the UCD 2D-PAGE open access database (http://proteomics-portal.ucd.ie/). Transit peptides, N-terminal acetylations and other PTMs are available via Peptideatlas (ftp://PASS00619:NM455hi@ftp.peptideatlas.org/). This dataset is associated with a research article published in the Journal of Proteomics [1].

Lipid- and mechanosensitivities of sodium/hydrogen exchangers analyzed by electrical methods.

Sodium/hydrogen exchangers (NHEs) are ubiquitous ion transporters that serve multiple cell functions. We have studied two mammalian isoforms, NHE1 (ubiquitous) and NHE3 (epithelial-specific), by measuring extracellular proton (H+) gradients during whole-cell patch clamp with perfusion of the cell interior. Maximal Na(+)-dependent H+ fluxes (JH+) are equivalent to currents >20 pA for NHE1 in Chinese hamster ovary fibroblasts, >200 pA for NHE1 in guinea pig ventricular myocytes, and 5-10 pA for NHE3 in opossum kidney cells. The fluxes are blocked by an NHE inhibitor, ethylisopropylamiloride, and are absent in NHE-deficient AP-1 cells. NHE1 activity is stable with perfusion of nonhydrolyzable ATP [adenosine 5'-(beta,gamma-imido)triphosphate], is abolished by ATP depletion (2 deoxy-D-glucose with oligomycin or perfusion of apyrase), can be restored with phosphatidylinositol 4,5-bisphosphate, and is unaffected by actin cytoskeleton disruption (latrunculin or pipette perfusion of gelsolin). NHE3 (but not NHE1) is reversibly activated by phosphatidylinositol 3,4,5-trisphosphate. Both NHE1 and NHE3 activities are disrupted in giant patches during gigaohm seal formation. NHE1 (but not NHE3) is reversibly activated by cell shrinkage, even at neutral cytoplasmic pH without ATP, and inhibited by cell swelling. NHE1 in Chinese hamster ovary fibroblasts (but not NHE3 in opossum kidney cells) is inhibited by agents that thin the membrane (L-alpha-lysophosphatidylcholine and octyl-beta-D-glucopyranoside) and activated by cholesterol enrichment, which thickens membranes. Expressed in AP-1 cells, however, NHE1 is insensitive to these agents but remains sensitive to volume changes. Thus, changes of hydrophobic mismatch can modulate NHE1 but do not underlie its volume sensitivity.

A variationist approach to the examination of insertion and deletion of /h/ in Kosraean English

I report on language variation in the unresearched variety of English emerging on Kosrae, Federated States of Micronesia. English is spoken as the inter-island lingua franca throughout Micronesia and has been the official language of FSM since gaining its independence in 1986, though still retaining close ties with the US through and economic “compact” agreement. I present here an analysis of a corpus of over 90 Kosraean English speakers, compiled during a three month fieldwork trip to the island in the Western Pacific. The 45 minute sociolinguistically sensitive recordings are drawn from a corpus of old and young, with varying levels of education and occupations, and off-island experiences. In the paper I analyse two variables. The first variable is the realisation of /h/, often subject to deletion in both L1 and L2 varieties of English. Such occurrences are commonly associated with Cockney English, but also found in Caribbean English and the postcolonial English of Australia. For example:  Male, 31: yeah I build their house their local huts and they pay me /h/ deletion is frequent in Kosraean English, but, perhaps expectedly, occurs slightly less among people with higher contact with American English, through having spent longer periods off island. The second feature under scrutiny is the variable epenthesis of [h] to provide a consonantal onset to vowel-initial syllables.  Male, 31: that guy is really hold now This practice is also found beyond Kosraean English. Previous studies find h-epenthesis arising in L1 varieties including Newfoundland and Tristan de Cunha English, while similar manifestations are identified in Francophone L2 learners of English. My variationist statistical analysis has shown [h] insertion:  to disproportionately occur intervocalically;  to be constrained by both speaker gender and age: older males are much more likely to epenthesis [h] in their speech;  to be more likely in the onset of stressed as opposed to unstressed syllables. In light of the findings of my analysis, I consider the relationship between h-deletion and h-epenthesis, the plausibility of hypercorrection as a motivation for the variation, and the potential influence of the substrate language, alongside sociolinguistic factors such as attitudes towards the US based on mobility. The analysis sheds light on the extent to which different varieties share this characteristic and the comparability of them in terms of linguistic constraints and attributes. Clarke, S. (2010). Newfoundland and Labrador English. Edinburgh: Edinburgh University Press Hackert, S. (2004). Urban Bahamian Creole: System and Variation. Varieties of English Around the World G32. Amsterdam: Benjamins Milroy, J. (1983). On the Sociolinguistic History of H-dropping in English in Current topics in English historical linguistics: Odense UP