Molecular heterogeneity of D-end products detected by anti-H-2.28 sera

Immunoprecipitation of NP-40 lysates of 125I-labeled lymph-node cells with different anti-H-2 sera and with anti-Qa-2 serum has shown that the BALB/cByA strain (H-2d, Qa-2-negative) expresses, besides H-2Ld, another molecule that is not detectable in the BALB/c-H-2dm2 strain. Electrophoresis in SDS polyacrylamide gels indicated that this molecule, provisionally designated Lq, has an apparent molecular weight of 41000 daltons, in contrast to approximately 49000 daltons for H-2Kd and H-2Ld, and 47000 daltons for H-2Dd molecules. The anti-Qa-2 serum precipitated from the Qa-2-positive strains BALB/cHeA but not from the Qa-2-negative strains BALB/cByA and BALB/c-H-2dm2 a protein that gave a very strong band corresponding to the molecular weight 41000 daltons in the gel electrophoresis. The biochemical characteristics of the Lq molecule are thus more similar to those of Qa-2 than of H-2 antigens.     

DNA sequence of the coding region of the HLA-B44 gene

An HLA-B44 cDNA clone was identified in a cDNA library constructed from an HLA-B44 homozygous cell line. The DNA sequence was determined and was found to contain the complete coding sequence but for (probably) the three N-terminal codons. Comparisons of the derived amino acid sequence with other HLA-A and -B locus amino acid sequences revealed four HLA-B44-specific substitutions including a new polymorphic site. Regions of strong sequence conservation for HLA-B-locus products were found at the nucleotide and amino acid levels.     

Mosaic trisomy 9: Two additional cases

Summary Two unrelated patients were found to be mosaic for an extra chromosome 9 (46,XX/47,XX,+9). The first patient showed a prominent nose, deep set eyes, carp shaped mouth and complex congenital cardiac anomalies. She died of congestive cardiac failure at the age of 10 days. The second patient, was a 7 1/2 year old female who had persistent alacrimia and mental retardation.     

Quantitative determination by real-time PCR of four vaginalLactobacillus species,Gardnerella vaginalisandAtopobium vaginaeindicates an inverse relationship betweenL. gasseriandL. iners

Background  

Most studies of the vaginal microflora have been based on culture or on qualitative molecular techniques. Here we applied existing real-time PCR formats forLactobacillus crispatus,L. gasseriandGardnerella vaginalisand developed new formats forAtopobium vaginae,L. inersandL. jenseniito obtain a quantitative non culture-based determination of these species in 71 vaginal samples from 32 pregnant and 28 non-pregnant women aged between 18 and 45 years.     

Predicting the effect of a point mutation on a protein fold: the villin and advillin headpieces and their Pro62Ala mutants

Homology modeling of unknown proteins is based on the assumption that highly similar sequences are likely to share the same fold. However, this does not provide any information on the stability of a given fold, which is ultimately determined by the subtle interplay of enthalpic and entropic contributions. Herein it is shown that ab initio atomistic simulations can be used to predict the effect of point mutations on the stability of a protein fold. The calculations indicate that the fold stabilities of two proteins of similar sequence and identical fold, the villin and advillin C-terminal headpiece fragments, are different and that the same P62A point mutation has a dramatic effect on the fold of villin but a minor one on that of advillin. These predictions were subsequently validated by NMR and CD experiments.     

Soil Carbon Stocks Decrease following Conversion of Secondary Forests to Rubber (Hevea brasiliensis) Plantations

Forest-to-rubber plantation conversion is an important land-use change in the tropical region, for which the impacts on soil carbon stocks have hardly been studied. In montane mainland southeast Asia, monoculture rubber plantations cover 1.5 million ha and the conversion from secondary forests to rubber plantations is predicted to cause a fourfold expansion by 2050. Our study, conducted in southern Yunnan province, China, aimed to quantify the changes in soil carbon stocks following the conversion from secondary forests to rubber plantations. We sampled 11 rubber plantations ranging in age from 5 to 46 years and seven secondary forest plots using a space-for-time substitution approach. We found that forest-to-rubber plantation conversion resulted in losses of soil carbon stocks by an average of 37.4±4.7 (SE) Mg C ha⁻¹ in the entire 1.2-m depth over a time period of 46 years, which was equal to 19.3±2.7% of the initial soil carbon stocks in the secondary forests. This decline in soil carbon stocks was much larger than differences between published aboveground carbon stocks of rubber plantations and secondary forests, which range from a loss of 18 Mg C ha⁻¹ to an increase of 8 Mg C ha⁻¹. In the topsoil, carbon stocks declined exponentially with years since deforestation and reached a steady state at around 20 years. Although the IPCC tier 1 method assumes that soil carbon changes from forest-to-rubber plantation conversions are zero, our findings show that they need to be included to avoid errors in estimating overall ecosystem carbon fluxes.     

Stable partial migration under a genetic threshold model of migratory behaviour

Many species show migratory behaviour in response to seasonal changes in environmental conditions. A peculiar, yet widespread phenomenon is partial migration, when a single population consists of both migratory and non‐migratory individuals. There are still many open questions regarding the stability and evolutionary significance of such populations. For passerines the inheritance of migratory activity is best described by the threshold model of quantitative genetics. Such a model has not yet been employed in theoretical studies, in which stability of partially migratory populations is usually linked to group differences in survival or reproduction. Here we develop a parsimonious model featuring a conditional genetic threshold for passerine migratory behaviour under which stable partial migration can be observed, and we explore the resulting selection landscape. Our model results show a cline in migratory behaviour across the landscape, from fully migratory populations to fully residential populations, with a fairly wide zone of partially migratory populations, which is stable in both time and space under a wide range of parameter settings. Temporal stability of the zone is linked with the yearly variance in both migration survival and resident winter survival. In contrast to other theoretical studies, we show that density dependence in winter survival is not essential for observing partially migratory populations. In addition, we observe that selection on the genetic threshold value occurs mainly at the borders of the zone of partial migration. This result suggests that fully migratory and fully residential populations in areas far from the zone of partial migration can harbour genetic diversity that allows the appearance of the alternative phenotype under (a wide range of) different conditions.     

Visceral leishmaniasis: what are the needs for diagnosis, treatment and control?

Visceral leishmaniasis (VL) is a systemic protozoan disease that is transmitted by phlebotomine sandflies. Poor and neglected populations in East Africa and the Indian sub-continent are particularly affected. Early and accurate diagnosis and treatment remain key components of VL control. In addition to improved diagnostic tests, accurate and simple tests are needed to identify treatment failures. Miltefosine, paromomycin and liposomal amphotericin B are gradually replacing pentavalent antimonials and conventional amphotericin B as the preferred treatments in some regions, but in other areas these drugs are still being evaluated in both mono- and combination therapies. New diagnostic tools and new treatment strategies will only have an impact if they are made widely available to patients.     

Diffusion Kurtosis Imaging and High-Resolution MRI Demonstrate Structural Aberrations of Caudate Putamen and Amygdala after Chronic Mild Stress

The pathophysiology of major depressive disorder (MDD) and other stress related disorders has been associated with aberrations in the hippocampus and the frontal brain areas. More recently, other brain regions, such as the caudate nucleus, the putamen and the amygdala have also been suggested to play a role in the development of mood disorders. By exposing rats to a variety of stressors over a period of eight weeks, different phenotypes, i.e. stress susceptible (anhedonic-like) and stress resilient animals, can be discriminated based on the sucrose consumption test. The anhedonic-like animals are a well validated model for MDD. Previously, we reported that in vivo diffusion kurtosis imaging (DKI) of the hippocampus shows altered diffusion properties in chronically stressed rats independent of the hedonic state and that the shape of the right hippocampus is differing among the three groups, including unchallenged controls. In this study we evaluated diffusion properties in the prefrontal cortex, caudate putamen (CPu) and amygdala of anhedonic-like and resilient phenotypes and found that mean kurtosis in the CPu was significantly different between the anhedonic-like and resilient animals. In addition, axial diffusion and radial diffusion were increased in the stressed animal groups in the CPu and the amygdala, respectively. Furthermore, we found that the CPu/brain volume ratio was increased significantly in anhedonic-like animals as compared with control animals. Concurrently, our results indicate that the effects of chronic stress on the brain are not lateralized in these regions. These findings confirm the involvement of the CPu and the amygdala in stress related disorders and MDD. Additionally, we also show that DKI is a potentially important tool to promote the objective assessment of psychiatric disorders.