Sexing of mid‐incubation avian embryos as a management tool for zoological breeding programs

Skewed sex ratios in zoo breeding programs may require housing single birds of an overrepresented gender, increasing demands on limited resources that could otherwise be diverted to breeding pairs or other important species. The ability to selectively incubate and hatch eggs of a desired sex represents a significant improvement in the long‐term management of avian species. This study describes a successful method for in ovo sexing of embryos from stage 30 through 42 of incubation (Hamburger and Hamilton [1951] J Morphol 88:49–92). A 0.01–1 µl blood sample was collected from either the vitelline vessel (VV) or the blood vessels of the chorio–allantoic membrane (CAM) of embryos at stages 14–18 or 30–42, respectively. DNA was isolated from whole blood using the Chelex method (Walsh et al. [1991] Biotechniques 10:506–513; Jensen et al., [2003] Zoo Biol 22:561–571). Sex was determined by PCR amplification using the previously described P2/P8 (Griffiths et al. [1998] Mol Ecol 7:1071–1075) and 1237L/1272H (Kahn et al. [1998] Auk 115:1074–1078) primers or by commercial vendor. Success rate was calculated as the percent of sampled embryos surviving to hatch. Embryos of the undesired sex were not incubated, thus not included in the calculation. There was a considerable difference in success rate when blood was collected from the stage 14–18 VV (0–25%, average 12%) vs. stage 30–42 CAM (33–100%, average 76%). In conclusion, in ovo sexing of embryos between stages 30 and 42 yields acceptable embryo survival rates while providing enough blood for genetic testing. Zoo Biol 31:694‐704, 2012. © 2011 Wiley Periodicals, Inc.     

Assessing current genetic status of the Hainan gibbon using historical and demographic baselines: implications for conservation management of species of extreme rarity

Evidence‐based conservation planning is crucial for informing management decisions for species of extreme rarity, but collection of robust data on genetic status or other parameters can be extremely challenging for such species. The Hainan gibbon, possibly the world's rarest mammal, consists of a single population of ~25 individuals restricted to one protected area on Hainan Island, China, and has persisted for over 30 years at exceptionally low population size. Analysis of genotypes at 11 microsatellite loci from faecal samples for 36% of the current global population and tissue samples from 62% of existing historical museum specimens demonstrates limited current genetic diversity (Na = 2.27, Ar = 2.24, H_e = 0.43); diversity has declined since the 19th century and even further within the last 30 years, representing declines of ~30% from historical levels (Na = 3.36, Ar = 3.29, H_e = 0.63). Significant differentiation is seen between current and historical samples (F_ST = 0.156, P = 0.0315), and the current population exhibits extremely small N_e (current N_e = 2.16). There is evidence for both a recent population bottleneck and an earlier bottleneck, with population size already reasonably low by the late 19th century (historical N_e = 1162.96). Individuals in the current population are related at the level of half‐ to full‐siblings between social groups, and full‐siblings or parent–offspring within a social group, suggesting that inbreeding is likely to increase in the future. The species' current reduced genetic diversity must be considered during conservation planning, particularly for expectations of likely population recovery, indicating that intensive, carefully planned management is essential.     

Pleistocene refugia in an arid landscape: analysis of a widely distributed Australian passerine

While many studies have documented the effect that glacial cycles have had on northern hemisphere species, few have attempted to study the associated effect of aridification at low latitudes in the southern hemisphere. We investigated the past effects that cyclic aridification may have had on the population structure and history of a widespread endemic Australian bird species, the Australian magpie (Gymnorhina tibicen). One thousand one hundred and sixty-six samples from across its native range were analysed for mitochondrial control region sequence variation and variation at six microsatellite loci. Analysis of mitochondrial control region sequence data indicated monophyletic clades that were geographically congruent with an eastern and western region. The contemporary distribution of east and west clades is nonoverlapping but in close proximity. Populations were estimated to have diverged in the Pleistocene around 36,000 years ago. The putative Carpentarian and Nullarbor arid barriers appear to be associated with the divergence between east and west mainland populations. Nested clade analysis indicated a signature of range expansion in the eastern region suggesting movement possibly inland and northward subsequent to the last period of aridity. The island population of Tasmania was of very recent origin, possibly since sea levels rose 16,000 years ago. Given the east-west structure, there was no congruence between morphology and recent history of this species indicating a lack of support for morphological taxa. Overall mitochondrial DNA and microsatellite variation suggest that increasing aridity and Pleistocene refugia played a role in structuring populations of the Australian magpie; however, the dispersal ability and generalist habitat requirements may have facilitated the movement of magpies into an almost contiguous modern distribution across the continent. This study supports the idea that Pleistocene aridification played an important role in structuring intraspecific variation in low latitudinal southern hemisphere avian species.     

Is traditional contraceptive use in Moldova associated with poverty and isolation?

This study investigates the correlates of traditional contraceptive use in Moldova, a poor country in Europe with one of the highest proportions of traditional contraceptive method users. The high reliance on traditional methods, particularly in the context of sub-replacement level fertility rate, has not been systematically evaluated in demographic research. Using cross-sectional data on a sub-sample of 6039 sexually experienced women from the 2005 Moldovan Demographic and Health Survey, this study hypothesizes that (a) economic and spatial disadvantages increase the likelihood of traditional method use, and (b) high exposure to family planning/reproductive health (FP/RH) programmes increases the propensity to modern method use. Multilevel multinomial models are used to examine the correlates of traditional method use controlling for exposure to sexual activity, socioeconomic and demographic characteristics and data structure. The results show that economic disadvantage increases the probability of traditional method use, but the overall effect is small. Although higher family planning media exposure decreases the reliance on traditional methods among younger women, it has only a marginal effect in increasing modern method use among older women. Family planning programmes designed to encourage women to switch from traditional to modern methods have some success--although the effect is considerably reduced in regions outside of the capital Chisinau. The study concludes that FP/RH efforts directed towards the poorest may have limited impact, but interventions targeted at older women could reduce the burden of unwanted pregnancies and abortions. Addressing differentials in accessing modern methods could improve uptake in rural areas.     

LipidWrapper: An Algorithm for Generating Large-Scale Membrane Models of Arbitrary Geometry

As ever larger and more complex biological systems are modeled in silico, approximating physiological lipid bilayers with simple planar models becomes increasingly unrealistic. In order to build accurate large-scale models of subcellular environments, models of lipid membranes with carefully considered, biologically relevant curvature will be essential. In the current work, we present a multi-scale utility called LipidWrapper capable of creating curved membrane models with geometries derived from various sources, both experimental and theoretical. To demonstrate its utility, we use LipidWrapper to examine an important mechanism of influenza virulence. A copy of the program can be downloaded free of charge under the terms of the open-source FreeBSD License from http://nbcr.ucsd.edu/lipidwrapper. LipidWrapper has been tested on all major computer operating systems.

This is a PLOS Computational Biology Software Article

     

Costimulation via CD55 on human CD4+ T cells mediated by CD97

Decay-accelerating factor (CD55) is a complement regulatory protein, which is expressed by most cells to protect them from complement-mediated attack. CD55 also binds CD97, an EGF-TM7 receptor constitutively expressed on granulocytes and monocytes and rapidly up-regulated on T and B cells upon activation. Early results suggested that CD55 could further enhance T cell proliferation induced by phorbol ester treatment. The present study demonstrates that coengagement of CD55, using either cross-linking mAbs or its natural ligand CD97, and CD3 results in enhanced proliferation of human peripheral blood CD4(+) T cells, expression of the activation markers CD69 and CD25, and secretion of IL-10 and GM-CSF. Recently, an increase in T cell responsiveness in CD55(-/-) mice was shown to be mediated by a lack of complement regulation. In this study, we show that direct stimulation of CD55 on CD4(+) T cells with CD97 can modulate T cell activation but does not interfere with CD55-mediated complement regulation. Our results support a multifaceted role for CD55 in human T cell activation, constituting a further link between innate and adaptive immunity.