Osteopontin is critical to determine symptom severity of influenza through the regulation of NK cell population

Osteopontin (OPN) is involved in exacerbating various inflammatory diseases. A severe pulmonary inflammation is frequently found in lethal influenza A virus (IAV) infection. However, the function of OPN against the infection was poorly understood. Here, we demonstrate an importance of OPN on immune response and disease severity after IAV infection. We found that the expression level of OPN was increased in mice infected with IAV. The OPN knockout (KO) mice exhibited a severe pathological phenotype and the survival rate decreased after the lethal IAV infection, compared to the wild type mice, while the survival rate increased in OPN transgenic (Tg) mice. The population of natural killer (NK) cells significantly decreased in OPN KO mice at day 5 after the infection, whereas, it increased in OPN Tg mice. These results suggest that OPN plays an important role in host defense against IAV infection through the regulation of NK cell population.     

Association of molecular markers in Plasmodium falciparum crt and mdr1 with in vitro chloroquine resistance: A Philippine study

Specific mutations in the pfcrt and pfmdr1 genes have been reported to be associated with chloroquine-resistant falciparum malaria parasites worldwide. These genetic markers are considered to be useful tools for the elucidation of several aspects of the epidemiology of drug resistant malaria. In this study, Plasmodium falciparum isolates from three distinct areas of the Philippines were analyzed for drug-resistance-associated genetic mutations, and their association with the in vitro chloroquine (CQ) response. Two novel pfcrt 72–76 allelic types, CVMDT and SVMDT, were detected. The frequency of the pfcrt K76T mutation in the isolates that were successfully tested for in vitro CQ susceptibility was found to be 100% in Kalinga, 80% in Palawan, and 87% in Mindanao. The frequency of the pfmdr1 N86Y mutation was 39% in Kalinga, 35% in Palawan, and 93% in Mindanao isolates. No mutations were found at positions 1042 and 1246 of pfmdr1. However, there were no significant associations found between polymorphisms in these genes and in vitro CQ susceptibility. The results of this study indicate that mutations in pfcrt and pfmdr1 are not predictive of in vitro CQ resistance in Philippine isolates and may therefore not be suitable as molecular markers for surveillance.     

NMR characterization of intramolecular interaction of osteopontin, an intrinsically disordered protein with cryptic integrin-binding motifs

Osteopontin (OPN) is an integrin-binding protein found in a variety of tissues and physiological fluids and is involved in divergent biological processes such as migration, adhesion and signaling in integrin-independent as well as dependent manners. The adhesive activity of this protein is modulated upon cleavage by thrombin at the central part of the molecule, in the vicinity of the integrin-binding sequences. Although detailed structural characterization is crucial for further understanding of the regulatory mechanisms of the OPN functions, its intrinsically disordered property hampers in-depth conformational analyses. Here we report an NMR study of mouse OPN and its N-terminal thrombin-cleavage product to characterize intramolecular interaction of this molecule. Paramagnetic relaxation enhancement experiment revealed that OPN exhibits a long-range intramolecular interaction between the N- and C-terminal regions. Furthermore, our NMR data showed that anti-OPN antibody OPN1.2, whose reactivity is impaired by deletion or amino acid substitutions of the arginine-aspartate-glycine integrin-binding motif, binds the N-terminal side of the integrin-binding motifs suggesting the existence of intramolecular interaction. These data suggest that functional interactions of OPN with integrins and the other binding partners can be modulated by the intramolecular interactions.     

Swine-origin influenza-virus-induced acute lung injury: Novel or classical pathogenesis?

Influenza viruses are common respiratory pathogens in humans and can cause serious infection that leads to the development of pneumonia. Due to their host-range diversity, genetic and antigenic diversity, and potential to reassort genetically in vivo, influenza A viruses are continual sources of novel influenza strains that lead to the emergence of periodic epidemics and outbreaks in humans. Thus, newly emerging viral diseases are always major threats to public health. In March 2009, a novel influenza virus suddenly emerged and caused a worldwide pandemic. The novel pandemic influenza virus was genetically and antigenically distinct from previous seasonal human influenza A/H1N1 viruses; it was identified to have originated from pigs, and further genetic analysis revealed it as a subtype of A/H1N1, thus later called a swine-origin influenza virus A/H1N1. Since the novel virus emerged, epidemiological surveys and research on experimental animal models have been conducted, and characteristics of the novel influenza virus have been determined but the exact mechanisms of pulmonary pathogenesis remain to be elucidated. In this editorial, we summarize and discuss the recent pandemic caused by the novel swine-origin influenza virus A/H1N1 with a focus on the mechanism of pathogenesis to obtain an insight into potential therapeutic strategies.     

Enumeration of the genusPeziza in Japan:Peziza limnaea andPeziza rifaii

Two species in the genusPeziza are described and illustrated as new to Japan:Peziza limnaea andPeziza rifaii. These species were collected in the broad-leaved forest mainly withCastanopsis cuspidata in Chiba Pref.     

Nucleotide sequence of the 5' flanking region responsible for the enhancement of the expression of yeast enolase 1 gene

Several plasmids carrying different length of the 5' flanking region of yeast (Saccharomyces cerevisiae) enolase 1 gene (ENO1) which is fused in frame to the Escherichia coli lacZ gene were constructed by recombination in vitro. Promoter activity of ENO1 was assayed by measuring beta-galactosidase activity of the fused gene product. Comparison of the promoter activity of these plasmids suggests that the sequences required for a strong promoter activity lie within the DNA segment -724 to -353 base pairs (bp) upstream from the start of ENO1 coding sequence. The nucleotide sequence of this region was determined.     

Membrane knobs of unfixed Babesia bovis-infected erythrocytes: new findings as revealed by atomic force microscopy and surface potential spectroscopy

Atomic force microscopy (AFM) and surface potential microscopy (SPS) were used to examine the structure of the knobs of unfixed Babesia bovis-infected erythrocytes, AFM revealed each knob was found to consist of two subunits, components that have not been observed in chemically fixed knobs by transmission electron microscopy. In addition, SPS revealed the knob surface has a positive electrical charge and that the remainder of the erythrocyte surface has a negative charge. These factors might be central to the phenomenon of cytoadherence in cerebral babesiosis.     

RGD–cyclam conjugate: Synthesis and potential application for positron emission tomography

Cyclam and DOTA-containing positron emission tomography radiotracers were prepared by using a modular chemical strategy based on peptide synthesis and chemoselective ligations. These molecules encompass two functional domains, one a tumour ‘homing’ domain and the other a chelating ligand for copper allowing nuclear imaging of tumours.