Prevalence of antibodies against Simkania negevensis in a healthy Japanese population determined by the microimmunofluorescence test

Simkania negevensis has been associated with bronchiolitis in infants and community-acquired pneumonia in adults. Reports of exposure to this microorganism are only available from Israel, North America and Western Europe. Currently, no standard method for diagnosis of S. negevensis infection has been established nor have prevalence rates been shown in Japan. For the first time we demonstrated the ability of the microimmunofluorescence (MIF) test to detect S. negevensis-specific immunoglobulin G and exposure to S. negevensis in Japan. The positive rate in healthy volunteers was 4.3% (25/588), with rates increasing with age. Results indicate the usefulness of the MIF test as a serological method for detecting S. negevensis-specific antibodies. A standard serological test for infection with S. negevensis is needed.     

Identification of <Emphasis Type="Italic">Porphyra yezoensis</Emphasis> (Rhodophyta) meiosis by DNA quantification using confocal laser scanning microscopy

Conchospore germlings of Porphyra yezoensis were stained with a fluorescent dye for DNA and observed with confocal laser scanning microscopy (CLSM). Relative DNA values of the germling nuclei were obtained by measuring fluorescence intensities of nuclear regions of the optically sliced specimens, using the mean value of the smallest blade cells as a reference of the genomic n value. Such quantification revealed that the nuclear DNA amounts of the one-cell, two-cell, and four-cell-stage germlings are approximately 4 × n, 2 × n, and n ∼2 × n values respectively; these values agreed well with the expected ones from the hypothesis that meiosis corresponds to the first successive cell divisions after the conchospore germination. These results are consistent with a previous study on cytogenetic analysis of the chimaera blade formation (Ohme and Miura 1988, Plant Sci 57:135–140) and not consistent with a recent microscopic study (Wang et al. 2006, Phycol Res 54:201–207) which proposed that the first meiotic division occurs at the conchospore formation and the second division at the germination.     

Antitumor activity of Nocardia cell wall skeleton preparations in transplantable tumors in syngeneic mice and patients with malignant pleurisy

Summary The antitumor activity of the cell wall skeleton preparations of four species of Nocardia, N. brasiliensis strain 146, N. coeliaca strain 122, N. polychromogenes strain 6, and N. rubra, which showed potent adjuvant activity on the induction of cell-mediated cytotoxicity in allogeneic mice, was examined with the aid of EL-4 leukemia, melanoma B16, and MH-134 hepatoma in syngeneic mice. Preliminary clinical trials were performed and the results suggest that the cell wall skeleton of N. rubra, upon intrapleural injection, may be useful as an immunotherapeutic agent for patients with malignant pleurisy. The chemical properties of these cell wall skeleton preparations are described.     

Biphasic action of phospholipase A in collagen-stimulated rat platelets

The formation of thromboxane A2 (TXA2) in collagen-stimulated rat platelets was successfully divided into two stages, an initial and a second one, by the specific TXA2 receptor antagonist, ONO3708. In the presence of this antagonist, only the initial TXA2 production was observed, without the subsequent platelet shape change and aggregation. Collagen causes the specific cleavage of arachidonic acid from phosphatidylinositol (PI) in the initial stage, whereas in the absence of the antagonist, it caused decrease in the arachidonic acid levels in phosphatidylethanolamine (PE) and PI with concomitant formation of the respective lyso-forms. These results demonstrate that phospholipase A (PLA) preferentially acts on PI to release arachidonic acid which leads to the initial TXA2 production, which might be a trigger for the second release of arachidonic acid from PE and PI.     

Probing antioxidant activity of 2′-hydroxychalcones: Crystal and molecular structures, in vitro antiproliferative studies and in vivo effects on glucose regulation

In order to better understand the antioxidant behavior of a series of polyphenolic 2′-hydroxychalcones, we describe the results of several chemical and biological studies, in vitro and in vivo. Single crystal X-ray methods elucidated their molecular structures and important intermolecular interactions such as H-bonding and molecular stacking in the crystal structures that contribute to our knowledge in explaining antioxidant activity. The results of experiments using the 1,1-diphenyl-2-dipicrylhydrazyl (DPPH) UV–vis spectroscopic method indicate that a hydroxyl group in position 5′ induces the highest antioxidant activity. Consequently, 2,2′,5′-trihydroxychalcone was selected for further study in vitro towards ROS scavenging in L-6 myoblasts and THP-1 human monocytes, where it shows an excellent antioxidant activity in a concentration range lower than that reported by most studies of related molecules. In addition, this chalcone shows a very selective activity: it inhibits the proliferation of leukemic cells, but it does not affect the normal L-6 myoblasts and human fibroblasts. In studying 2,2′,5′-trihydroxychalcone's effect on weight gain and serum glucose and insulin levels in Zucker fatty (fa⁻/fa⁻) rats we found that supplementing the diet with a 10 mg/kg dose of this chalcone (3 times weekly) blunted the increase in glucose that co-occurs with weight gain over the 6-week treatment period. It is concluded that 2,2′,5′-trihydroxychalcone has the potential to serve as a protective agent for some debilitating diseases.     

Genetic diversity,structure, and demography of Pandanus boninensis (Pandanaceae) with sea drifted seeds,endemic to the Ogasawara Islands of Japan: Comparison between young and old islands

Pandanus boninensis, endemic to the Ogasawara Islands, Japan, is distributed on both the older Bonin and younger Volcano Islands. In this study, we conducted population genetic analyses of P. boninensis on these islands to examine the population diversity and structure across old and young islands, to assess potential differences in population demography with island age, and to collect any evidence of migration between old and young islands. We found that the genetic diversity of expressed sequence tag (EST)–based microsatellite (SSR) markers, the nucleotide diversity of nuclear DNA sequences, and the haplotype diversity of chloroplast DNA on young islands were lower than those on old islands. Clustering analyses of EST‐SSR indicated that populations on old islands were strongly diverged from those on young islands. Approximate Bayesian computation analysis of EST‐SSR suggested that population expansion occurred on old islands while population reduction occurred on young islands. We also found evidence of migration among old islands (mostly from south to north), while it appears that there have been very few migration events between old and young islands. These differences could be due to the fact that young islands tend to be geographically isolated and support smaller populations that began a shorter time ago from limited founders. The P. boninensis populations on the Volcano Islands are interesting from an evolutionary perspective as they constitute a classic example of the early stages of progressive colonization on oceanic islands with small effective population sizes and low genetic diversity.     

Prolactin induces MFG-E8 production in macrophages via transcription factor C/EBPβ-dependent pathway

The lactogenic hormone prolactin (PRL) regulates milk protein gene expression in mammary glands. To maintain homeostatic balance in the body, milk fat globule epidermal growth factor 8 (MFG-E8) is vital for phagocytic clearance of apoptotic cells. We investigated the effects of PRL on MFG-E8 expression in macrophages by evaluating its promoter function. Macrophages were stimulated with PRL, and the expression of MFG-E8 was determined using real-time PCR and Western blotting. The role of MFG-E8 on phagocytosis of apoptotic cells in PRL-treated macrophages was assessed using microscopy, while the response of PRL to MFG-E8 expression was evaluated using luciferase assay. Following treatment with PRL, significant up-regulations of the PRL receptor and MFG-E8 were observed in macrophages, though PRL-treated macrophages more efficiently engulfed apoptotic cells. The results of MFG-E8 promoter analysis showed considerable up-regulation of promoter activity in macrophages following PRL treatment and results from mutation analysis of the MFG-E8 promoter suggested that the C/EBPβ binding site was responsible for PRL-induced activation of the MFG-E8 promoter. C/EBPβ activity was found to be up-regulated in PRL-treated cells as revealed by an electrophoretic mobility shift assay (EMSA). In conclusion, PRL is a potent inducer of MFG-E8 expression in macrophages, while its effect is mediated by the presence of a responsive element in the MFG-E8 promoter.     

Sterol biosynthesis by a prokaryote: first in vitro identification of the genes encoding squalene epoxidase and lanosterol synthase from Methylococcus capsulatus

Sterol biosynthesis by prokaryotic organisms is very rare. Squalene epoxidase and lanosterol synthase are prerequisite to cyclic sterol biosynthesis. These two enzymes, from the methanotrophic bacterium Methylococcus capsulatus, were functionally expressed in Escherichia coli. Structural analyses of the enzymatic products indicated that the reactions proceeded in a complete regio- and stereospecific fashion to afford (3S)-2,3-oxidosqualene from squalene and lanosterol from (3S)-2,3-oxidosqualene, in full accordance with those of eukaryotes. However, our result obtained with the putative lanosterol synthase was inconsistent with a previous report that the prokaryote accepts both (3R)- and (3S)-2,3-oxidosqualenes to afford 3-epi-lanosterol and lanosterol, respectively. This is the first report demonstrating the existence of the genes encoding squalene epoxidase and lanosterol synthase in prokaryotes by establishing the enzyme activities. The evolutionary aspect of prokaryotic squalene epoxidase and lanosterol synthase is discussed.     

Human group III phospholipase A2 suppresses adenovirus infection into host cells. Evidence that group III, V and X phospholipase A2s act on distinct cellular phospholipid molecular species

Of 10 mammalian secreted phospholipase A(2) (sPLA(2)) enzymes identified to date, group V and X sPLA(2)s, which are two potent plasma membrane-acting sPLA(2)s, are capable of preventing host cells from being infected with adenovirus, and this anti-viral action depends on the conversion of phosphatidylcholine (PC) to lysophosphatidylcholine (LPC) in the host cell membrane. Here, we show that human group III sPLA(2), which is structurally more similar to bee venom PLA(2) than to other mammalian sPLA(2)s, also has the capacity to inhibit adenovirus infection into host cells. Mass spectrometry (MS) demonstrated that group III sPLA(2) hydrolyzes particular molecular species of PC to generate LPC in human bronchial epithelial cells. Remarkably, in addition to the catalytically active sPLA(2) domain, the N-terminal, but not C-terminal, domain unique to this enzyme was required for the anti-adenovirus effect. To our knowledge, this is the first demonstration that the biological action of group III sPLA(2) depends on its N-terminal domain. Finally, our MS analysis provided additional and novel evidence that group III, V and X sPLA(2)s target distinct phospholipid molecular species in cellular membranes.