Crystal structure of the Anabaena sensory rhodopsin transducer.

We present crystal structures of the Anabaena sensory rhodopsin transducer (ASRT), a soluble cytoplasmic protein that interacts with the first structurally characterized eubacterial retinylidene photoreceptor Anabaena sensory rhodopsin (ASR). Four crystal structures of ASRT from three different spacegroups were obtained, in all of which ASRT is present as a planar (C4) tetramer, consistent with our characterization of ASRT as a tetramer in solution. The ASRT tetramer is tightly packed, with large interfaces where the well-structured beta-sandwich portion of the monomers provides the bulk of the tetramer-forming interactions, and forms a flat, stable surface on one side of the tetramer (the beta-face). Only one of our four different ASRT crystals reveals a C-terminal alpha-helix in the otherwise all-beta protein, together with a large loop from each monomer on the opposite face of the tetramer (the alpha-face), which is flexible and largely disordered in the other three crystal forms. Gel-filtration chromatography demonstrated that ASRT forms stable tetramers in solution and isothermal microcalorimetry showed that the ASRT tetramer binds to ASR with a stoichiometry of one ASRT tetramer per one ASR photoreceptor with a K(d) of 8 microM in the highest affinity measurements. Possible mechanisms for the interaction of this transducer tetramer with the ASR photoreceptor via its flexible alpha-face to mediate transduction of the light signal are discussed

Long-term moderate calorie restriction inhibits inflammation without impairing cell-mediated immunity: A randomized controlled trial in non-obese humans

Calorie restriction (CR) inhibits inflammation and slows aging in many animal species, but in rodents housed in pathogen-free facilities, CR impairs immunity against certain pathogens. However, little is known about the effects of long-term moderate CR on immune function in humans. In this multi-center, randomized clinical trial to determine CR's effect on inflammation and cell-mediated immunity, 218 healthy non-obese adults (20-50 y), were assigned 25% CR (n=143) or an ad-libitum (AL) diet (n=75), and outcomes tested at baseline, 12, and 24 months of CR. CR induced a 10.4% weight loss over the 2-y period. Relative to AL group, CR reduced circulating inflammatory markers, including total WBC and lymphocyte counts, ICAM-1 and leptin. Serum CRP and TNF-α concentrations were about 40% and 50% lower in CR group, respectively. CR had no effect on the delayed-type hypersensitivity skin response or antibody response to vaccines, nor did it cause difference in clinically significant infections. In conclusion, long-term moderate CR without malnutrition induces a significant and persistent inhibition of inflammation without impairing key in vivo indicators of cell-mediated immunity. Given the established role of these pro-inflammatory molecules in the pathogenesis of multiple chronic diseases, these CR-induced adaptations suggest a shift toward a healthy phenotype

Age-associated alterations in CXCL1 chemokine expression by murine B cells

BACKGROUND: The CXCL1 chemokines, macrophage inflammatory protein-2 (MIP-2) and cytokine-induced neutrophil chemoattractant (KC), have been shown to play a role in a number of pathophysiological disease states including endotoxin-induced inflammation and bacterial meningitis. While the expression of these chemokines has been identified in a variety of cell types in the mouse, little is known about their expression with murine B-lymphocytes. RESULTS: Here, we demonstrate that highly purified murine splenic B cells are capable of expressing both MIP-2 and KC protein and mRNA upon activation with lipopolysaccharide (LPS) but not in response to anti-μ and anti-CD40 in combination with interleukin-4 (IL-4) stimulation. Moreover, these chemokines are expressed at higher levels in B cells derived from young (4 m) compared to old (24–29 m) mice. Upon fractionation into distinct B-cell subsets, we found that the expression of MIP-2 and KC by aged follicular (FO) B cells is significantly decreased when compared to the same cells from younger mice, while only MIP-2 production was found to be diminished in aged marginal zone (MZ) B cells. Interestingly, MIP-2 and KC production by newly formed (NF) B cells did not significantly differ with age. Moreover, the potential relevance of these findings is supported by the poor ability of LPS-activated aged B cells to specifically mediate CXCL1-dependent leukocyte recruitment when compared to younger B cells. CONCLUSION: Overall, the decreased expression of CXCL1 chemokines by aged B cells in response to LPS may have potential implications on the secondary recruitment of leukocytes to sites of microbial infections and inflammation possibly contributing to the increased susceptibility of older subjects to pathogen challenge

Optical phase dynamics in mutually coupled diode laser systems exhibiting power synchronization

We probe the physical mechanism behind the known phenomenon of power synchronization of two diode lasers that are mutually coupled via their delayed optical fields. In a diode laser, the amplitude and the phase of the optical field are coupled by the so-called linewidth enhancement factor, $\alpha$. In this work, we explore the role of optical phases of the electric fields in amplitude (and hence power) synchronization through $\alpha$ in such mutually delay-coupled diode laser systems. Our numerical results show that the synchronization of optical phases drives the powers of lasers to synchronized death regimes. We also find that as $\alpha$ varies for different diode lasers, the system goes through a sequence of in-phase amplitude-death states. Within the windows between successive amplitude-death regions, the cross-correlation between the field amplitudes exhibits a universal power-law behaviour with respect to $\alpha$.Comment: J. Phys. B: At. Mol. Opt. Phys. 44 (2011

Direct and indirect effects of retinoic acid on human Th2 cytokine and chemokine expression by human T lymphocytes

BACKGROUND: Vitamin A (VA) deficiency induces a type 1 cytokine response and exogenously provided retinoids can induce a type 2 cytokine response both in vitro and in vivo. The precise mechanism(s) involved in this phenotypic switch are inconsistent and have been poorly characterized in humans. In an effort to determine if retinoids are capable of inducing Th2 cytokine responses in human T cell cultures, we stimulated human PBMCs with immobilized anti-CD3 mAb in the presence or absence of all-trans retinoic acid (ATRA) or 9-cis-RA. RESULTS: Stimulation of human PBMCs and purified T cells with ATRA and 9-cis-RA increased mRNA and protein levels of IL-4, IL-5, and IL-13 and decreased levels of IFN-γ, IL-2, IL-12p70 and TNF-α upon activation with anti-CD3 and/or anti-CD28 mAbs. These effects were dose-dependent and evident as early as 12 hr post stimulation. Real time RT-PCR analysis revealed a dampened expression of the Th1-associated gene, T-bet, and a time-dependent increase in the mRNA for the Th2-associated genes, GATA-3, c-MAF and STAT6, upon treatment with ATRA. Besides Th1 and Th2 cytokines, a number of additional proinflammatory and regulatory cytokines including several chemokines were also differentially regulated by ATRA treatment. CONCLUSION: These data provide strong evidence for multiple inductive roles for retinoids in the development of human type-2 cytokine responses

A study of effect of intra umbilical oxytocin in active management of third stage of labour

Background: Postpartum haemorrhage is a single major and leading cause of maternal morbidity and mortality. PPH is the loss of more than 500 ml blood following vaginal delivery or 1000 ml blood following caesarean section. India has a maternal mortality ratio of 167 per 1 lakh live births. The most common cause of maternal mortality is haemorrhage which accounts for 25-30% of maternal mortality of which PPH is a significant cause. Methods: 200 patients were included in this prospective observational study and divided into two groups, group A, underwent only active management of third stage of labour and group B received intra umbilical oxytocin administration in addition to AMTSL. The maternal and neonatal outcome was observed between the two and the difference was noted. Results: Mean duration of third stage of labour of group A patients was 3.89±0.89 minutes and Mean blood loss was 386±85.30 ml and that of group B patients was 1.96±0.68 minutes and 235±72.99 ml respectively. These were found to be statistically significant among all the other parameters. Conclusions: The duration of third stage of labour and the amount of postpartum blood loss was significantly less when intra umbilical injection of oxytocin was used in addition to AMTSL. So, to conclude intra umbilical vein oxytocin injection should be used routinely in addition to AMTSL in order to prevent PPH

Controlled meal frequency without caloric restriction alters peripheral blood mononuclear cell cytokine production

<p>Abstract</p> <p>Background</p> <p>Intermittent fasting (IF) improves healthy lifespan in animals by a mechanism involving reduced oxidative damage and increased resistance to stress. However, no studies have evaluated the impact of controlled meal frequency on immune responses in human subjects.</p> <p>Objective</p> <p>A study was conducted to establish the effects of controlled diets with different meal frequencies, but similar daily energy intakes, on cytokine production in healthy male and female subjects.</p> <p>Design</p> <p>In a crossover study design with an intervening washout period, healthy normal weight middle-age male and female subjects (n = 15) were maintained for 2 months on controlled on-site one meal per day (OMD) or three meals per day (TMD) isocaloric diets. Serum samples and peripheral blood mononuclear cells (PBMCs) culture supernatants from subjects were analyzed for the presence of inflammatory markers using a multiplex assay.</p> <p>Results</p> <p>There were no significant differences in the inflammatory markers in the serum of subjects on the OMD or TMD diets. There was an increase in the capacity of PBMCs to produce cytokines in subjects during the first month on the OMD or TMD diets.</p> <p>Lower levels of TNF-α, IL-17, MCP-1 and MIP-1β were produced by PBMCs from subjects on the OMD versus TMD diet.</p> <p>Conclusions</p> <p>PBMCs of subjects on controlled diets exhibit hypersensitivities to cellular stimulation suggesting that stress associated with altered eating behavior might affect cytokine production by immune cells upon stimulation. Moreover, stimulated PBMCs derived from healthy individuals on a reduced meal frequency diet respond with a reduced capability to produce cytokines.</p