The rockefeller university

A burst in the production of pro-inflammatory molecules characterizes the beginning of the host response to infection. Cytokines, chemokines, and growth factors work in concert to control pathogen replication and activate innate and adaptive immune responses. Granulocyte colony-stimulating factor (G-CSF) mobilizes and activates hematopoietic cells from the bone marrow, and it has been shown to mediate the generation of effective immunity against bacterial and fungal infections. G-CSF is produced at high levels in the lungs during infection with influenza and parainfluenza viruses, but its role during these infections is unknown. Here we show that during infection of mice with a non-lethal dose of influenza or Sendai virus, G-CSF promotes the accumulation of activated Ly6G(+) granulocytes that control the extent of the lung pro-inflammatory response. Remarkably, these G-CSF-mediated effects facilitate viral clearance and sustain mouse survival.

We look back on the discoveries that the tyrosine kinases TYK2 and JAK1 and the transcription factors STAT1, STAT2, and IRF9 are required for the cellular response to type I interferons. This initial description of the JAK-STAT pathway led quickly to additional discoveries that type II interferons and many other cytokines signal through similar mechanisms. This well-understood pathway now serves as a paradigm showing how information from protein-protein contacts at the cell surface can be conveyed directly to genes in the nucleus. We also review recent work on the STAT proteins showing the importance of several different post-translational modifications, including serine phosphorylation, acetylation, methylation, and sumoylation. These remarkably proficient proteins also provide noncanonical functions in transcriptional regulation and they also function in mitochondrial respiration and chromatin organization in ways that may not involve transcription at all.

A large body of literature provides compelling evidence for the role of evolutionarily conserved core histone residues in various biological processes. However, site-directed mutagenesis of individual residues that are known to be sites of posttranslational modifications often does not result in clear phenotypic defects. In some cases, the combination of multiple mutations can give rise to stronger phenotypes, implying functional redundancy between distinct residues on histones. Here, we examined the "histone redundancy hypothesis" by characterizing double deletion of all pairwise combinations of amino-terminal tails (N-tails) from the four core histones encoded in budding yeast. First, we found that multiple lysine residues on the N-tails of both H2A and H4 are redundantly involved in cell viability. Second, simultaneous deletion of N-tails from H2A and H3 leads to a severe growth defect, which is correlated with perturbed gross chromatin structure in the mutant cells. Finally, by combining point mutations on H3 with deletion of the H2A N-tail, we revealed a redundant role for lysine 4 on H3 and the H2A N-tail in hydroxyurea-mediated response. Altogether, these data suggest that the N-tails of core histones share previously unrecognized, potentially redundant functions that, in some cases are different from those of the widely accepted H2A/H2B and H3/H4 dimer pairs.

Staphylococcus haemolyticus is one of the most clinically relevant coagulase-negative staphylococci (CoNS), particularly in immunocompromised patients; however, little is known regarding its molecular epidemiology. In this work, we characterized the genetic background and the SCCmec region of 36 methicillin-resistant S. haemolyticus (MRSHae) and 10 methicillin-susceptible S. haemolyticus (MSSHae) collected from neutropenic patients in Tunisia between 2002 and 2004. The molecular characterization of MRSHae by pulsed-field gel electrophoresis (PFGE) showed that the great majority of the isolates (77.8%) belonged to only four types. SCCmec typing by polymerase chain reaction (PCR) and Southern hybridization showed that isolates belonging to each PFGE type could carry either one or two SCCmec types. SCCmec V was the most common, but mec complex C was frequently associated to ccr allotypes other than ccrC. The mec complex class C was predominant in MRSHae (47%) and ccrC was predominant among both methicillin-resistant and -susceptible isolates (31 and 50%, respectively). Interestingly, one half (50%) of the MRSHae isolates analyzed lacked the known ccr complexes (ccrand ccrC), although they carried the mecA. Conversely, all MSSHae carrying a ccrC complex were multidrug-resistant, although they lack the mecA. The results suggest that ccrC and mec complex C are frequent and may exist autonomously and independently of SCCmec type V in S. haemolyticus. Moreover, the data obtained suggest that small chromosomal rearrangements promoting the loss or structural variation of mec and ccr complex appear to occur frequently, which probably provide S. haemolyticus with a specialized means for SCCmec trapping and/or diversification.

Dendritic cells (DC) are antigen-presenting cells found in both lymphoid and nonlymphoid organs, including the brain (bDC) of Cd11c/eyfp transgenic C57BL/6 mice. Using an intranasal vesicular stomatitis virus infection, we demonstrated that EYFP+ cells amass in areas associated with viral antigens, take on an activated morphology, and project their processes into infected neuronal tissue within the olfactory bulb. These bDC separated into three EYFP+ CD45(+) CD11b(+) populations, all but one being able to functionally promote both T lymphocyte proliferation and T(H)1 cytokine production. One population was shown to emanate from the brain and a second population was peripherally derived. The third population was of indeterminate origin, being both radiosensitive and not replenished by donor bone marrow. Finally, each EYFP+ population contained CD11b(+) CD103(+) subpopulations and could be distinguished in terms of CD115, Gr-1, and Ly-6C expression, highlighting mucosal and monocyte-derived DC lineages.

A search for the standard model Higgs boson decaying into two Z bosons with subsequent decay into a final state containing two quark jets and two leptons, H -> ZZ((*)) -> q (q) over barl(-)l(+) is presented. Results are based on data corresponding to an integrated luminosity of 4.6 fb(-1) of proton-proton collisions at root s = 7TeV, collected with the CMS detector at the LHC. In order to discriminate between signal and background events, kinematic and topological quantities, including the angular spin correlations of the decay products, are employed. Events are further classified according to the probability of the jets to originate from quarks of light or heavy flavor or from gluons. No evidence for the Higgs boson is found, and upper limits on its production cross section are determined for a Higgs boson of mass between 130 and 600 GeV

Editorial Introduction for the Allostatic Load special issue. (C) 2012 Elsevier Inc. All rights reserved.

To investigate the effects of visible light on the retinal development, we established an early-light-exposure model in neonatal mice. An incision was made on the right-sided eyelids of mice on postnatal day 4 (P4), and so that the right eyes were exposed to visible light (4000 lux) for 12 h per day. The population in the retinal ganglion cells (RGCs), cellular apoptosis and lumican expression were analyzed in the retinae. The loss of the RGCs was moderately alleviated and dramatically increased by early light exposure on P9 and P12, respectively. In the light-exposed retinae, the immunoactivities of caspase-9 (p39), an active isoform of caspase-9 marking the cellular apoptosis, dropped to nearly 30% of those in the control specimens on P6; thereafter the light-induced lower levels of caspase-9 (p39) remained, while those in the control specimens dropped to the values less than 50% of the light-exposed retinae. Lumican was first ectopically detected on P9, and distributed in the inner layers of the light-exposed retinae, with the most significant accumulation in the ganglion cell layer by P12. The ectopic expression of lumican was both temporarily and spatially parallel with the aggravated loss of the RGCs. In conclusion, early light exposure inflicts a profound effect on the immature retina. Our studies may have implications for premature infant care. (C) 2012 Elsevier Inc. All rights reserved.

The vast majority of bacteria present in environmental samples have never been cultured and therefore have not been exploited for the ability to produce useful biocatalysts or collections of biocatalysts generating interesting small molecules. Metagenomic libraries constructed using DNA extracted directly from natural bacterial communities offer access to the genetic information present in the genomes of these as yet uncultured bacteria. This review highlights recent efforts to recover both discrete enzymes and small molecules from metagenomic libraries.

How do adverse childhood experiences get 'under the skin' and influence health outcomes through the life-course? Research reviewed here suggests that adverse childhood experiences are associated with changes in biological systems responsible for maintaining physiological stability through environmental changes, or allostasis. Children exposed to maltreatment showed smaller volume of the prefrontal cortex, greater activation of the HPA axis, and elevation in inflammation levels compared to non-maltreated children. Adults with a history of childhood maltreatment showed smaller volume of the prefrontal cortex and hippocampus, greater activation of the HPA axis, and elevation in inflammation levels compared to non-maltreated individuals. Despite the clear limitations in making longitudinal claims from cross-sectional studies, work so far suggests that adverse childhood experiences are associated with enduring changes in the nervous, endocrine, and immune systems. These changes are already observable in childhood years and remain apparent in adult life. Adverse childhood experiences induce significant biological changes in children (biological embedding), modifying the maturation and the operating balance of allostatic systems. Their chronic activation can lead to progressive wear and tear, or allostatic load and overload, and, thus, can exert long-term effects on biological aging and health. (C) 2011 Elsevier Inc. All rights reserved.