Interaction of monocytes with NK cells upon Toll-like receptor-induced expression of the NKG2D ligand MICA

Reciprocal interactions between NK cells and dendritic cells have been shown to influence activation of NK cells, maturation, or lysis of dendritic cells and subsequent adaptive immune responses. However, little is known about the crosstalk between monocytes and NK cells and the receptors involved in this interaction. We report in this study that human monocytes, upon TLR triggering, up-regulate MHC class I-Related Chain (MIC) A, but not other ligands for the activating immunoreceptor NKG2D like MICB or UL-16 binding proteins 1-3. MICA expression was associated with CD80, MHC class I and MHC class II up-regulation, secretion of proinflammatory cytokines, and apoptosis inhibition, but was not accompanied by release of MIC molecules in soluble form. TLR-induced MICA on the monocyte cell surface was detected by autologous NK cells as revealed by NKG2D down-regulation. Although MICA expression did not render monocytes susceptible for NK cell cytotoxicity, LPS-treated monocytes stimulated IFN-gamma production of activated NK cells which was substantially dependent on MICA-NKG2D interaction. No enhanced NK cell proliferation or cytotoxicity against third-party target cells was observed after stimulation of NK cells with LPS-activated monocytes. Our data indicate that MICA-NKG2D interaction constitutes a mechanism by which monocytes and NK cells as an early source of IFN-gamma may communicate directly during an innate immune response to infections in humans.     

Associations of the Polymorphisms in DHRS4, SERPING1, and APOR Genes with Postmortem pH in Berkshire Pigs

Postmortem pH is a main factor influencing the meat quality in pigs. This study investigated the association of postmortem pH with single-nucleotide polymorphisms (SNPs) in the fourth member of the short-chain dehydrogenase/reductase family (DHRS4), the first member of serpin peptidase inhibitor, clade G (complement inhibitor) (SERPING1), and the apolipoprotein R precursor (APOR) genes in Berkshire pigs. The study included 437 pigs, and genotyping was conducted using the GoldenGate Assay (Illumina, San Diego, CA, USA). DHRS4, SERPING1, and APOR polymorphisms were significantly associated with pH₄₅ or pH₂₄ (p?SERPING1 was also statistically significantly associated with water holding capacity (p?DHRS4, SERPING1, and APOR genes have potential for use as genetic markers for the meat quality in pigs.     

Insulation and wiring specificity of BceR‐like response regulators and their target promoters in Bacillus subtilis

BceRS and PsdRS are paralogous two‐component systems in Bacillus subtilis controlling the response to antimicrobial peptides. In the presence of extracellular bacitracin and nisin, respectively, the two response regulators (RRs) bind their target promoters, P_bceA or P_psdA, resulting in a strong up‐regulation of target gene expression and ultimately antibiotic resistance. Despite high sequence similarity between the RRs BceR and PsdR and their known binding sites, no cross‐regulation has been observed between them. We therefore investigated the specificity determinants of P_bceA and P_psdA that ensure the insulation of these two paralogous pathways at the RR–promoter interface. In vivo and in vitro analyses demonstrate that the regulatory regions within these two promoters contain three important elements: in addition to the known (main) binding site, we identified a linker region and a secondary binding site that are crucial for functionality. Initial binding to the high‐affinity, low‐specificity main binding site is a prerequisite for the subsequent highly specific binding of a second RR dimer to the low‐affinity secondary binding site. In addition to this hierarchical cooperative binding, discrimination requires a competition of the two RRs for their respective binding site mediated by only slight differences in binding affinities.     

Supplement of nutrients for effective cultivation of hepatitis B surface antigen-producing recombinant yeast

Summary In the hepatitis B surface antigen (HBsAg)-producing recombinant yeast culture medium, the supply of Bacto-yeast nitrogen base without amino acids was found to be inadequate due to the lack of the several kinds of vitamins and trace elements. When the culture medium for this recombinant yeast was supplemented with sufficient vitamins and trace elements, its growth, HBsAg production and the stability of plasmid were improved.     

Effect of heterologous xylose transporter expression in Candida tropicalis on xylitol production rate

Xylose utilization is inhibited by glucose uptake in xylose-assimilating yeasts, including Candida tropicalis, resulting in limitation of xylose uptake during the fermentation of glucose/xylose mixtures. In this study, a heterologous xylose transporter gene (At5g17010) from Arabidopsis thaliana was selected because of its high affinity for xylose and was codon-optimized for functional expression in C. tropicalis. The codon-optimized gene was placed under the control of the GAPDH promoter and was integrated into the genome of C. tropicalis strain LXU1 which is xyl2-disrupted and NXRG (codon-optimized Neurospora crassa xylose reductase) introduced. The xylose uptake rate was increased by 37–73 % in the transporter expression-enhanced strains depending on the glucose/xylose mixture ratio. The recombinant strain LXT2 in 500-mL flask culture using glucose/xylose mixtures showed a xylose uptake rate that was 29 % higher and a xylitol volumetric productivity (1.14 g/L/h) that was 25 % higher than the corresponding rates for control strain LXU1. Membrane protein extraction and Western blot analysis confirmed the successful heterologous expression and membrane localization of the xylose transporter in C. tropicalis.     

Comparative secretome analysis of human follicular dermal papilla cells and fibroblasts using shotgun proteomics

The dermal papilla cells (DPCs) of hair follicles are known to secrete paracrine factors for follicular cells. Shotgun proteomic analysis was performed to compare the expression profiles of the secretomes of human DPCs and dermal fibroblasts (DFs). In this study, the proteins secreted by DPCs and matched DFs were analyzed by 1DE/LTQ FTICR MS/MS, semi-quantitatively determined using emPAI mole percent values and then characterized using protein interaction network analysis. Among the 1,271 and 1,188 proteins identified in DFs and DPCs, respectively, 1,529 were further analyzed using the Ingenuity Pathway Analysis tool. We identified 28 DPC-specific extracellular matrix proteins including transporters (ECM1, A2M), enzymes (LOX, PON2), and peptidases (C3, C1R). The biochemically- validated DPC-specific proteins included thrombospondin 1 (THBS1), an insulin-like growth factor binding protein3 (IGFBP3), and, of particular interest, an integrin beta1 subunit (ITGB1) as a key network core protein. Using the shotgun proteomic technique and network analysis, we selected ITGB1, IGFBP3, and THBS1 as being possible hair-growth modulating protein biomarkers.     

A road map for molecular ecology

The discipline of molecular ecology has undergone enormous changes since the journal bearing its name was launched approximately two decades ago. The field has seen great strides in analytical methods development, made groundbreaking discoveries and experienced a revolution in genotyping technology. Here, we provide brief perspectives on the main subdisciplines of molecular ecology, describe key questions and goals, discuss common challenges, predict future research directions and suggest research priorities for the next 20 years.     

Low-temperature time-resolved spectroscopic study of the major light-harvesting complex of Amphidinium carterae

The major light-harvesting complex of Amphidinium (A.) carterae, chlorophyll-a–chlorophyll-c ₂–peridinin–protein complex (acpPC), was studied using ultrafast pump-probe spectroscopy at low temperature (60 K). An efficient peridinin–chlorophyll-a energy transfer was observed. The stimulated emission signal monitored in the near-infrared spectral region was stronger when redder part of peridinin pool was excited, indicating that these peridinins have the S₁/ICT (intramolecular charge-transfer) state with significant charge-transfer character. This may lead to enhanced energy transfer efficiency from “red” peridinins to chlorophyll-a. Contrary to the water-soluble antenna of A. carterae, peridinin–chlorophyll-a protein, the energy transfer rates in acpPC were slower under low-temperature conditions. This fact underscores the influence of the protein environment on the excited-state dynamics of pigments and/or the specificity of organization of the two pigment–protein complexes.     

Vacuolar zinc transporter Zrc1 is required for detoxification of excess intracellular zinc in the human fungal pathogen <Emphasis Type="Italic">Cryptococcus neoformans</Emphasis>

Zinc is an important transition metal in all living organisms and is required for numerous biological processes. However, excess zinc can also be toxic to cells and cause cellular stress. In the model fungus Saccharomyces cerevisiae, a vacuolar zinc transporter, Zrc1, plays important roles in the storage and detoxification of excess intracellular zinc to protect the cell. In this study, we identified an ortholog of the S. cerevisiae ZRC1 gene in the human fungal pathogen Cryptococcus neoformans. Zrc1 was localized in the vacuolar membrane in C. neoformans, and a mutant lacking ZRC1 showed significant growth defects under high-zinc conditions. These results suggested a role for Zrc1 in zinc detoxification. However, contrary to our expectation, the expression of Zrc1 was induced in cells grown in zinc-limited conditions and decreased upon the addition of zinc. These expression patterns were similar to those of Zip1, the high-affinity zinc transporter in the plasma membrane of C. neoformans. Furthermore, we used the zrc1 mutant in a murine model of cryptococcosis to examine whether a mammalian host could inhibit the survival of C. neoformans using zinc toxicity. We found that the mutant showed no difference in virulence compared with the wildtype strain. This result suggests that Zrc1-mediated zinc detoxification is not required for the virulence of C. neoformans, and imply that zinc toxicity may not be an important aspect of the host immune response to the fungus.