1H, 13C and 15N resonances of the AlgE62 subunit from Azotobacter vinelandii mannuronan C5-epimerase

The 17.7 kDa R2 module from Azotobacter vinelandii mannronan C5-epimerase AlgE6 has been isotopically labeled (¹³C,¹⁵N) and recombinantly expressed. Here we report the ¹H, ¹³C, ¹⁵N resonance assignment of AlgE6R2.     

NMR assignments of 1H, 13C and 15N resonances of the C-terminal subunit from Azotobacter vinelandii mannuronan C5-epimerase 6 (AlgE6R3)

The 19.9 kDa C-terminal module (R3) from Azotobacter vinelandii mannronan C5-epimerase AlgE6 has been ¹³C, ¹⁵N isotopically labelled and recombinantly expressed. We report here the ¹H, ¹³C, ¹⁵N resonance assignment of AlgE6R3.     

Peripheral-specific y2 receptor knockdown protects mice from high-fat diet-induced obesity

Y2 receptors, particularly those in the brain, have been implicated in neuropeptide Y (NPY)-mediated effects on energy homeostasis and bone mass. Recent evidence also indicates a role for Y2 receptors in peripheral tissues in this process by promoting adipose tissue accretion; however their effects on energy balance remain unclear. Here, we show that adult-onset conditional knockdown of Y2 receptors predominantly in peripheral tissues results in protection against diet-induced obesity accompanied by significantly reduced weight gain, marked reduction in adiposity and improvements in glucose tolerance without any adverse effect on lean mass or bone. These changes occur in association with significant increases in energy expenditure, respiratory exchange ratio, and physical activity and despite concurrent hyperphagia. On a chow diet, knockdown of peripheral Y2 receptors results in increased respiratory exchange ratio and physical activity with no effect on lean or bone mass, but decreases energy expenditure without effecting body weight or food intake. These results suggest that peripheral Y2 receptor signaling is critical in the regulation of oxidative fuel selection and physical activity and protects against the diet-induced obesity. The lack of effects on bone mass seen in this model further indicates that bone mass is primarily controlled by non-peripheral Y2 receptors. This study provides evidence that novel drugs that target peripheral rather than central Y2 receptors could provide benefits for the treatment of obesity and glucose intolerance without adverse effects on lean and bone mass, with the additional benefit of avoiding side effects often associated with pharmaceuticals that act on the central nervous system.     

Comparative proteome analysis of Brucella abortus 2308 and its virB type IV secretion system mutant reveals new T4SS-related candidate proteins

Brucella abortus is an alpha-2 proteobacteria with a type IV secretion system (T4SS) known as virB, which is necessary to gain virulence by building up a replicative vacuole associated with the endoplasmic reticulum of the host cell. A virB T4SS mutant of the B. abortus 2308 strain and its wild-type strain were grown in acid medium in order to obtain and analyze their proteomes, looking for putative proteins that may serve as T4SS substrates and those that may be subjected to T4SS regulation. A total of 47 overexpressed and 22 underexpressed proteins from the virB T4SS mutant strain were selected and sequenced. Some of the 69 analyzed proteins have not been described before either as over or under-expressed in relation to a virB T4SS mutation, whereas some of them have been already described by other groups as potentially important secretory proteins in other Brucella species. An important number of the proteins identified are outer membrane and periplasmic space protein, which makes them become particularly important new T4SS-related candidate proteins.     

A proteomic study of in-root interactions between chickpea pathogens: the root-knot nematode Meloidogyne artiellia and the soil-borne fungus Fusarium oxysporum f. sp. ciceris race 5

Fusarium wilt caused by the fungus Fusarium oxysporum f. sp. ciceris (Foc) is the main soil-borne disease limiting chickpea production. Management of this disease is achieved mainly by the use of resistant cultivars. However, co-infection of a Foc-resistant plant by the fungus and the root-knot nematode Meloidogyne artiellia (Ma) causes breakdown of the resistance and thus limits its efficacy in the control of Fusarium wilt. In this work we aimed to reveal key aspects of chickpea:Foc:Ma interactions, studying fungal- and nematode-induced changes in root proteins, using chickpea lines 'CA 336.14.3.0' and 'ICC 14216K' that show similar resistant (Foc race 5) and susceptible (Ma) responses to either pathogen alone but a differential response after co-infection with both pathogens. 'CA 336.14.3.0' and 'ICC 14216K' chickpea plants were challenged with Foc race 5 and Ma, either in single or in combined inoculations, and the root proteomes were analyzed by two-dimensional gel electrophoresis using three biological replicates. Pairwise comparisons of treatments indicated that 47 protein spots in 'CA 336.14.3.0' and 31 protein spots in 'ICC 14216K' underwent significant changes in intensity. The responsive protein spots tentatively identified by MALDI TOF-TOF MS (27 spots for 'CA 336.14.3.0' and 15 spots for 'ICC 14216K') indicated that same biological functions were involved in the responses of either chickpea line to Foc race 5 and Ma, although common as well as line-specific responsive proteins were found within the different biological functions. To the best of our knowledge, this is the first study at the root proteome level of chickpea response to a biotic stress imposed by single and joint infections by two major soil-borne pathogens.     

The influence of different stresses on glomalin levels in an arbuscular mycorrhizal fungus--salinity increases glomalin content

Glomalin is a glycoprotein produced by arbuscular mycorrhizal (AM) fungi, and the soil fraction containing glomalin is correlated with soil aggregation. Thus, factors potentially influencing glomalin production could be of relevance for this ecosystem process and for understanding AM fungal physiology. Previous work indicated that glomalin production in AM fungi may be a stress response, or related to suboptimal mycelium growth. We show here that environmental stress can enhance glomalin production in the mycelium of the AM fungus Glomus intraradices. We applied NaCl and glycerol in different intensities to the medium in which the fungus was grown in vitro, causing salinity stress and osmotic stress, respectively. As a third stress type, we simulated grazing on the extraradical hyphae of the fungus by mechanically injuring the mycelium by clipping. NaCl caused a strong increase, while the clipping treatment led to a marginally significant increase in glomalin production. Even though salinity stress includes osmotic stress, we found substantially different responses in glomalin production due to the NaCl and the glycerol treatment, as glycerol addition did not cause any response. Thus, our results indicate that glomalin is involved in inducible stress responses in AM fungi for salinity, and possibly grazing stress.     

Interferon-α abrogates tolerance induction by human tolerogenic dendritic cells

Background

Administration of interferon-α (IFN-α) represents an approved adjuvant therapy as reported for malignancies like melanoma and several viral infections. In malignant diseases, tolerance processes are critically involved in tumor progression. In this study, the effect of IFN-α on tolerance induction by human tolerogenic dendritic cells (DC) was analyzed. We focussed on tolerogenic IL-10-modulated DC (IL-10 DC) that are known to induce anergic regulatory T cells (iTregs).

Methodology/Principal Findings

IFN-α promoted an enhanced maturation of IL-10 DC as demonstrated by upregulation of the differentiation marker CD83 as well as costimulatory molecules. IFN-α treatment resulted in an increased capacity of DC to stimulate T cell activation compared to control tolerogenic DC. We observed a strengthened T cell proliferation and increased IFN-γ production of CD4⁺ and CD8⁺ T cells stimulated by IFN-α-DC, demonstrating a restoration of the immunogenic capacity of tolerogenic DC in the presence of IFN-α. Notably, restimulation experiments revealed that IFN-α treatment of tolerogenic DC abolished the induction of T cell anergy and suppressor function of iTregs. In contrast, IFN-α neither affected the priming of iTregs nor converted iTregs into effector T cells.

Conclusions/Significance

IFN-α inhibits the induction of T cell tolerance by reversing the tolerogenic function of human DC.     

Function of the sex chromosomes in mammalian fertility

The sex chromosomes play a highly specialized role in germ cell development in mammals, being enriched in genes expressed in the testis and ovary. Sex chromosome abnormalities (e.g., Klinefelter [XXY] and Turner [XO] syndrome) constitute the largest class of chromosome abnormalities and the commonest genetic cause of infertility in humans. Understanding how sex-gene expression is regulated is therefore critical to our understanding of human reproduction. Here, we describe how the expression of sex-linked genes varies during germ cell development; in females, the inactive X chromosome is reactivated before meiosis, whereas in males the X and Y chromosomes are inactivated at this stage. We discuss the epigenetics of sex chromosome inactivation and how this process has influenced the gene content of the mammalian X and Y chromosomes. We also present working models for how perturbations in sex chromosome inactivation or reactivation result in subfertility in the major classes of sex chromosome abnormalities.