Interleukin-1 Receptor–Associated Kinase M–Deficient Mice Demonstrate an Improved Host Defense during Gram-negative Pneumonia

Pneumonia is a common cause of morbidity and mortality and the most frequent source of sepsis. Bacteria that try to invade normally sterile body sites are recognized by innate immune cells through pattern recognition receptors, among which toll-like receptors (TLRs) feature prominently. Interleukin-1 receptor (IL-1R)–associated kinase (IRAK)-M is a proximal inhibitor of TLR signaling expressed by epithelial cells and macrophages in the lung. To determine the role of IRAK-M in host defense against bacterial pneumonia, IRAK-M-deficient (IRAK-M^−/−) and normal wild-type (WT) mice were infected intranasally with Klebsiella pneumoniae. IRAK-M mRNA was upregulated in lungs of WT mice with Klebsiella pneumonia, and the absence of IRAK-M resulted in a strongly improved host defense as reflected by reduced bacterial growth in the lungs, diminished dissemination to distant body sites, less peripheral tissue injury and better survival rates. Although IRAK-M^−/− alveolar macrophages displayed enhanced responsiveness toward intact K. pneumoniae and Klebsiella lipopolysaccharide (LPS) in vitro, IRAK-M^−/− mice did not show increased cytokine or chemokine levels in their lungs after infection in vivo. The extent of lung inflammation was increased in IRAK-M^−/− mice shortly after K. pneumoniae infection, as determined by semiquantitative scoring of specific components of the inflammatory response in lung tissue slides. These data indicate that IRAK-M impairs host defense during pneumonia caused by a common gram-negative respiratory pathogen.     

Citrullination, a possible functional link between susceptibility genes and rheumatoid arthritis

Antibodies directed to citrullinated proteins (anti-cyclic citrullinated peptide) are highly specific for rheumatoid arthritis (RA). Recent data suggest that the antibodies may be involved in the disease process of RA and that several RA-associated genetic factors might be functionally linked to RA via modulation of the production of anti-cyclic citrullinated peptide antibodies or citrullinated antigens.     

Identification of host‐plant chemical stimuli for the European grape berry moth Eupoecilia ambiguella

Olfaction is of major importance for survival and reproduction in moths. Males possess highly specific and sensitive olfactory receptor neurones to detect female sex pheromones. However, the capacity of male moths to respond to host‐plant volatiles is relatively neglected and the role that such responses could play in the sensory ecology of moths is still not fully understood. The present study aims to identify host‐plant stimuli for the European grape berry moth Eupoecilia ambiguella Hb. (Tortricidae, Lepidoptera), a major pest of vine in Europe. Headspace volatiles from Vitis vinifera L. cv. Pinot Noir, Vitis vinifera subsp. sylvestris and five other host‐plant species comprising five different families are analyzed by gas chromatography linked to electroantennogram (EAG) recording from male E. ambiguella antennae and by gas chromatography‐mass spectrometry. This procedure identifies 32 EAG‐active compounds, among them the aliphatic compounds 1‐hexanol, (Z)‐3‐hexenol, (Z)‐3‐hexenyl acetate and 1‐octen‐3‐ol; the terpenes limonene, β‐caryophyllene and (E)‐4,8‐dimethyl‐1,3,7‐nonatriene; and the aromatic compounds benzaldehyde and methyl salicylate. Male and female E. ambiguella show similar EAG response amplitudes to individual chemical stimuli and also to mixtures of plant volatiles, as represented by essential oils from ten other plant species. This possibly indicates a common role for plant compounds in the sensory ecology of the two sexes of E. ambiguella.     

Simulium metallicum cytospecies E larval habitat characterization in the Altamira focus of onchocerciasis, northern Venezuela

Abstract. Simulium metallicum sibling species E was identified cytotaxonomically from an onchocerciasis focus at Altamira in northern Venezuela. S. metallicum E larvae were sampled monthly from two small mountain streams over a 15-month period (July 1990 to September 1991) and eleven habitat variables were measured at two altitudes. One stream consistently harboured much higher densities of S. metallicum E larvae than the other, with three annual peaks of abundance: during the dry season and at the beginning and end of the rainy season. These peak densities were correlated with high rainfall 4 months previously. Larvae were most abundant on submerged rocks and fallen leaves, in small shallow areas characterized by slow water current, high conductivity and sparse terrestrial vegetation cover. Stream variables which best explained the temporal changes in abundance were water discharge and conductivity. The population dynamics of S. metallicum E appeared to be influenced primarily by interactions between stream discharge and substrate stability. Relevance of these results to vector control with larvicides is discussed.     

From descriptive to predictive distribution models: a working example with Iberian amphibians and reptiles

Background

The two sympatric species of Tunisian desert ants, Cataglyphis bicolor and C. mauritanica, do not exhibit any differences in their foraging ecology, e.g. in food preferences and in their spatial and temporal activity patterns. Here we show that instead the two species markedly differ in their life histories.

Results

We analysed mtDNA of specimens that were collected along a 250-km transect. C. bicolor exhibited a genetically unstructured population (with the genetic and geographic distances among colonies not being correlated). On the contrary the populations of the polygynous C. mauritanica were clearly structured, i.e. exhibited a strong correlation between genetic and geographic distances. This difference is in accordance with large queen dispersal distances due to far-reaching mating flights in C. bicolor and small queen dispersal distances due to colony foundation by budding in C. mauritanica. Furthermore, wherever we found populations of both species to coexist within the same habitat, the habitat was used agriculturally. Mapping nest positions over periods of several years showed that plowing dramatically decreased the nest densities of either species.

Conclusion

We conclude that owing to its greater queen dispersal potential C. bicolor might be more successful in quickly re-colonizing disturbed areas, while the slowly dispersing C. mauritanica could later out-compete C. bicolor by adopting its effective nest-budding strategy. According to this scenario the observed sympatry of the two species might be an intermediate stage in which faster colonization by one species and more powerful exploitation of space by the other species have somehow balanced each other out. In conclusion, C. bicolor and C. mauritanica represent an example where environmental disturbances in combination with different life histories might beget sympatry in congeneric species with overlapping niches.     

Morphology and fine structure of the gravid uterus of three hymenolepidid tapeworm species (Platyhelminthes: Cestoda)

Summary

The ultrastructure of the uterus in gravid proglottids of Hymenolepis citelli, Vampirolepis nana and Vampirolepis microstoma was examined using transmission and scanning electron microscopy. The cellular and subcellular structures were similar in all three species, consisting basically of a syncytial layer attached to a basal extracellular matrix. All nuclei were juxtaluminal and each contained a single large centrally located nucleolus and prominent masses of central and peripheral heterochromatin. The cytoplasm showed evidence suggesting a high level of protein synthesis and secretion. It consisted primarily of granular endoplasmic reticulum with moderately dilated cisternae; most cisternae were completely filled with an electron-lucent flocculent material, but others contained electrondense granules. Free ribosomes and mitochondria were also present. The apical plasma membrane and a small amount of enclosed cytoplasm were folded into long microlamellae that extended into the uterine lumen. Larger epithelial folds and villi consisting of folded portions of the entire epithelium projected into the uterine lumen. The uterine epithelium along with its basul extracellular matrix and underlying cellular parenchyma were folded into the lumen at several points, forming epitheliomesenchymal folds and villi that closely apposed many of the eggs.     

Inhibition of mTOR affects protein stability of OGT

Autophagy regulates cellular homeostasis through degradation of aged or damaged subcellular organelles and components. Interestingly, autophagy-deficient beta cells, for example Atg7-mutant mice, exhibited hypoinsulinemia and hyperglycemia. Also, autophagy response is diminished in heart of diabetic mice. These results implied that autophagy and diabetes are closely connected and affect each other. Although protein O-GlcNAcylation is up-regulated in hyperglycemia and diabetes, and O-GlcNAcylated proteins play an important role in metabolism and nutrient sensing, little is known whether autophagy affects O-GlcNAc modification and vice versa. In this study, we suppressed the action of mTOR by treatment of mTOR catalytic inhibitors (PP242 and Torin1) to induce autophagic flux. Results showed a decrease in global O-GlcNAcylation, which is due to decreased OGT protein and increased OGA protein. Interestingly, knockdown of ATG genes or blocking of lysosomal degradation enhanced protein stability of OGT. In addition, when proteasomal inhibitor was treated together with mTOR inhibitor, protein level of OGT almost recovered to control level. These data suggest that mTOR inhibition is a more efficient way to reduce protein level of OGT rather than that of CHX treatment. We also showed that not only proteasomal degradation regulated OGT stability but autophagic degradation also affected OGT stability in part. We concluded that mTOR signaling regulates protein O-GlcNAc modification through adjustment of OGT stability.