Differential role of TLR- and RLR-signaling in the immune responses to influenza A virus infection and vaccination

The innate immune system recognizes influenza A virus via TLR 7 or retinoic acid-inducible gene I in a cell-type specific manner in vitro, however, physiological function(s) of the MyD88- or interferon-beta promoter stimulator 1 (IPS-1)-dependent signaling pathways in antiviral responses in vivo remain unclear. In this study, we show that although either MyD88- or IPS-1-signaling pathway was sufficient to control initial antiviral responses to intranasal influenza A virus infection, mice lacking both pathways failed to show antiviral responses, resulting in increased viral load in the lung. By contrast, induction of B cells or CD4 T cells specific to the dominant hemagglutinin or nuclear protein Ags respectively, was strictly dependent on MyD88 signaling, but not IPS-1 signaling, whereas induction of nuclear protein Ag-specific CD8 T cells was not impaired in the absence of either MyD88 or IPS-1. Moreover, vaccination of TLR7- and MyD88-deficient mice with inactivated virus failed to confer protection against a lethal live virus challenge. These results strongly suggest that either the MyD88 or IPS-1 signaling pathway is sufficient for initial antiviral responses, whereas the protective adaptive immune responses to influenza A virus are governed by the TLR7-MyD88 pathway.     

Phage display for engineering and analyzing protein interaction interfaces

Phage display is the longest-standing platform among molecular display technologies. Recent developments have extended its utility to proteins that were previously recalcitrant to phage display. The technique has played a dominant role in forming the field of synthetic binding protein engineering, where novel interfaces have been generated from libraries built using antibody fragment frameworks and also alternative scaffolds. Combinatorial methods have also been developed for the rapid analysis of binding energetics across protein interfaces. The ability to rapidly select and analyze binding interfaces, and compatibility with high-throughput methods under diverse conditions, makes it likely that the combination of phage display and synthetic combinatorial libraries will prove to be the method of choice for synthetic binding protein engineering for broad applications.     

Streptococcus panodentis sp. nov. from the oral cavities of chimpanzees

Three strains TKU9, TKU49 and TKU50^T, were isolated from the oral cavities of chimpanzees (Pan troglodytes). The isolates were all gram‐positive, facultative anaerobic cocci that lacked catalase activity. Analysis of partial 16S rRNA gene sequences showed that the most closely related species was Streptococcus infantis (96.7%). The next most closely related species to the isolates were S. rubneri, S. mitis, S. peroris and S. australis (96.6 to 96.4%). Based on the rpoB and gyrB gene sequences, TKU50^T was clustered with other member of the mitis group. Enzyme activity and sugar fermentation patterns differentiated this novel bacterium from other members of the mitis group streptococci. The DNA G + C content of strain TKU50^T was 46.7 mol%, which is the highest reported value for members of the mitis group (40–46 mol%). On the basis of the phenotypic characterization, partial 16S rRNA gene and sequences data for two housekeeping gene (gyrB and rpoB), we propose a novel taxa, S. panodentis for TKU 50^T (type strain = CM 30579^T = DSM 29921^T), for these newly described isolates.     

Independent Molecular Basis of Convergent Highland Adaptation in Maize

Convergent evolution is the independent evolution of similar traits in different species or lineages of the same species; this often is a result of adaptation to similar environments, a process referred to as convergent adaptation. We investigate here the molecular basis of convergent adaptation in maize to highland climates in Mesoamerica and South America, using genome-wide SNP data. Taking advantage of archaeological data on the arrival of maize to the highlands, we infer demographic models for both populations, identifying evidence of a strong bottleneck and rapid expansion in South America. We use these models to then identify loci showing an excess of differentiation as a means of identifying putative targets of natural selection and compare our results to expectations from recently developed theory on convergent adaptation. Consistent with predictions across a wide parameter space, we see limited evidence for convergent evolution at the nucleotide level in spite of strong similarities in overall phenotypes. Instead, we show that selection appears to have predominantly acted on standing genetic variation and that introgression from wild teosinte populations appears to have played a role in highland adaptation in Mexican maize.     

Sex- and age-related differences in morbidity rates of 2009 pandemic influenza A H1N1 virus of swine origin in Japan

Background

The objective of the present study was to determine whether the morbidity rates of the 2009 pandemic influenza A H1N1 virus (pdmH1N1) varied by age and/or sex.

Methods and Findings

Retrospective analysis of 2,024,367 cases of pdmH1N1 was performed using the national surveillance data from influenza sentinel points in Japan. The male-to-female morbidity ratios (M/F ratios) in nineteen age groups were estimated as the primary outcome. The M/F ratios for pdmH1N1 influenza were: >1 in age groups <20 years and ≥80 years (p<0.001); <1 in age groups 20–79 years (p<0.001). This data suggests that males <20 years of age may be more likely to suffer from pdmH1N1 influenza than females in the same age categories. When the infection pattern for pdmH1N1was compared with that of seasonal influenza outbreaks between 2000 and 2008, the M/F ratio for pdmH1N1 influenza was higher in ages 3–29 years and lower in ages 40–79 years. Because the present study was based on the national surveillance, it was impossible to estimate the morbidity rate for the Japanese population. It is also likely that the data did not capture asymptomatic or mild infections.

Conclusions

Although exposure to the pdmH1N1 virus is assumed to be similar in both boys and girls, M/F ratios were >1 in those younger than 20 years. The subsequent reversal of the M/F ratio in the adult generation could be due to several possibilities, including: greater immunity among adult males, more asymptomatic infections among males, less reporting of illness by males, or differences in exposure to the virus and probability of visiting a clinic. These results suggest that the infection and virulence patterns of pdmH1N1 are more complex than previously considered.     

A novel role of group VIB calcium-independent phospholipase A2 (iPLA2gamma) in the inducible expression of group IIA secretory PLA2 in rat fibroblastic cells

Group IIA secretory phospholipase A(2) (sPLA(2)-IIA) is a prototypic sPLA(2) enzyme that may play roles in modification of eicosanoid biosynthesis as well as antibacterial defense. In several cell types, inducible expression of sPLA(2) by pro-inflammatory stimuli is attenuated by group IVA cytosolic PLA(2) (cPLA(2)alpha) inhibitors such as arachidonyl trifluoromethyl ketone, leading to the proposal that prior activation of cPLA(2)alpha is required for de novo induction of sPLA(2). However, because of the broad specificity of several cPLA(2)alpha inhibitors used so far, a more comprehensive approach is needed to evaluate the relevance of this ambiguous pathway. Here, we provide evidence that the induction of sPLA(2)-IIA by pro-inflammatory stimuli requires group VIB calcium-independent PLA(2) (iPLA(2)gamma), rather than cPLA(2)alpha, in rat fibroblastic 3Y1 cells. Results with small interfering RNA unexpectedly showed that the cytokine induction of sPLA(2)-IIA in cPLA(2)alpha knockdown cells, in which cPLA(2)alpha protein was undetectable, was similar to that in replicate control cells. By contrast, knockdown of iPLA(2)gamma, another arachidonyl trifluoromethyl ketone-sensitive intracellular PLA(2), markedly reduced the cytokine-induced expression of sPLA(2)-IIA. Supporting this finding, the R-enantiomer of bromoenol lactone, an iPLA(2)gamma inhibitor, suppressed the cytokine-induced sPLA(2)-IIA expression, whereas (S)-bromoenol lactone, an iPLA(2)beta inhibitor, failed to do so. Moreover, lipopolysaccharide-stimulated sPLA(2)-IIA expression was also abolished by knockdown of iPLA(2)gamma. These findings open new insight into a novel regulatory role of iPLA(2)gamma in stimulus-coupled sPLA(2)-IIA expression.     

Distribution of Sorbitol, Neutral Sugars, Free Amino Acids, Malic Acid and Some Hydrolytic Enzymes in Vacuoles of Apple Cotyledons

Vacuoles of apple cotyledons (Malus pumila Mill. var. domesticaSchneid.) were obtained by purification with Ficoll densitygradient centrifugation after the protoplasts were lysed byboth osmotic shock and the addition of EDTA. High levels ofacid protease and carboxypeptidase activity were detected inthe vacuoles along with acid phosphatase, phosphodiesteraseand ATPase. The distribution of sorbitol and other sugars inthe vacuoles, the protoplast and extracellular free space wasdetermined. About 45, 60 and 90% of the sorbitol, glucose andsucrose, respectively, contained in whole tissue were foundin the extracellular free space, and 54% of the sorbitol inthe protoplast was detected in the vacuole. The sorbitol inthe vacuoles and the extravacuole of the protoplast was about80 and 70%, respectively, of the total sugar content of thecell. Arginine was the most abundant free amino acid in theprotoplast, and about 90% of it was contained in the vacuole.More than 80% of the total amino acids and 50% of the proteinwere also located in the vacuole, as well as most of the malate.The amounts of the total sugars, total amino acids, proteinand malate in the vacuoles were to 250, 400, 48 and 9 µg/10⁶cells, respectively. The results suggest that the vacuoles ofapple cotyledons contain a large pool of amino acids and proteinsrather than sugars, and have a close connection with proteinbody degradation. ¹ This paper is contribution A-l37 of the Fruit Tree ResearchStation. (Received January 20, 1982; Accepted May 18, 1982)