Alcohol and aldehyde dehydrogenase genotypes and drinking behavior of Chinese living in Shanghai

Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH), the principal enzymes responsible for oxidative metabolism of ethanol, exist in multiple, genetically determined molecular forms. Widely different kinetic properties in some of these isozymes account for the individual differences in alcohol sensitivity. In this study we used the polymerase chain reaction/restriction fragment length polymorphism method to determine the genotypes of the ADH2 and ALDH2 loci of alcoholic and nonalcoholic Chinese living in Shanghai. We also investigated the subjects' drinking patterns by means of semistructured interviews. The alcoholics had significantly lower frequencies of the ADH2² and ALDH2² alleles than did the nonalcoholics, suggesting the inhibitory effects of these alleles for the development of alcoholism. In the nonalcoholic subjects, ADH2² had little, if any, effect, despite the significant effect of the ALDH2² allele in decreasing the alcohol consumption of the individual. Taken together, these results fit the proposed hypothesis for the development of alcoholism, i.e., drinking behavior is greatly influenced by the individual's gentoypes of alcohol-metabolizing enzymes, and the risk of becoming alcoholic is proportionate with the ethanol consumption of the individual.     

PLRP2 selectively localizes synaptic membrane proteins via acyl-chain remodeling of phospholipids

The plasma membrane of neurons consists of distinct domains, each of which carries specialized functions and a characteristic set of membrane proteins. While this compartmentalized membrane organization is essential for neuronal functions, it remains controversial how neurons establish these domains on the laterally fluid membrane. Here, using immunostaining, lipid-MS analysis and gene ablation with the CRISPR/Cas9 system, we report that the pancreatic lipase-related protein 2 (PLRP2), a phospholipase A1 (PLA1), is a key organizer of membrane protein localization at the neurite tips of PC12 cells. PLRP2 produced local distribution of 1-oleoyl-2-palmitoyl-PC at these sites through acyl-chain remodeling of membrane phospholipids. The resulting lipid domain assembled the syntaxin 4 (Stx4) protein within itself by selectively interacting with the transmembrane domain of Stx4. The localized Stx4, in turn, facilitated the fusion of transport vesicles that contained the dopamine transporter with the domain of the plasma membrane, which led to the localized distribution of the transporter to that domain. These results revealed the pivotal roles of PLA1, specifically PLRP2, in the formation of functional domains in the plasma membrane of neurons. In addition, our results suggest a mode of membrane organization in which the local acyl-chain remodeling of membrane phospholipids controls the selective localization of membrane proteins by regulating both lipid-protein interactions and the fusion of transport vesicles to the lipid domain.     

Developmental expression profiles of axon guidance signaling and the immune system in the marmoset cortex: Potential molecular mechanisms of pruning of dendritic spines during primate synapse formation in late infancy and prepuberty (I)

The synapse number and the related dendritic spine number in the cerebral cortex of primates shows a rapid increase after birth. Depending on the brain region and species, the number of synapses reaches a peak before adulthood, and pruning takes place after this peak (overshoot-type synaptic formation). Human mental disorders, such as autism and schizophrenia, are hypothesized to be a result of either too weak or excessive pruning after the peak is reached. Thus, it is important to study the molecular mechanisms underlying overshoot-type synaptic formation, particularly the pruning phase.     

Inhibition of fungal ABC transporters by unnarmicin A and unnarmicin C, novel cyclic peptides from marine bacterium

Novel inhibitors of fungal ATP-binding cassette transporters were obtained by screening compounds and crude extracts from marine-derived fungi and bacteria using disk diffusion assays of Saccharomyces cerevisiae strains overexpressing a variety of fungal multi-drug efflux pumps. The cyclodepsipeptides unnarmicin A and unnarmicin C were able to sensitize cells overexpressing azole drug pumps ScPdr5p, CaCdr1p, CgCdr1p, and CgPdh1p to sub-MIC concentrations of fluconazole without affecting the growth of CaCdr2p and CaMdr1p overexpressing cells. Unnarmicin A and unnarmicin C were potent inhibitors of rhodamine 6G efflux of CaCdr1p expressing cells with IC₅₀ values of 3.61 and 5.65 μM, respectively. They inhibited the in vitro CaCdr1p ATPase activity at IC₅₀ values of 0.495 and 0.688 μM, respectively. And most importantly, they were able to sensitize azole-resistant Candida albicans clinical isolates to fluconazole. Unnarmicin A and unnarmicin C are candidate efflux pump inhibitors with the potential to be used as adjuvants for antifungal chemotherapy.     

Accumulation of Phenylpropanoids in Cotyledons of Morning Glory (Pharbitis nil) Seedlings during the Induction of Flowering by Poor Nutrition

Flowering of Pharbitis nil strain Violet is induced in continuouslight under poor nutritional conditions. High-performance liquidchromatography of extracts of the cotyledons revealed that twocompounds in addition to chlorogenic acid accumulate under suchconditions. The compounds were identified as pinoresinol glucosideand p-coumaroylquinic acid. The endogenous levels of these phenylpropanoidswere correlated with the flowering response when nutrition waspoor. However, activation of phenylpropanoid biosynthesis seemednot to be essential for the induction of flowering. (Received May 17, 1993; Accepted July 26, 1993)     

Conformational behavior of oxygenated mycobacterial mycolic acids from Mycobacterium bovis BCG

Phase diagrams of Langmuir monolayers of oxygenated mycolic acids, i.e. methoxy mycolic acid (MeO-MA), ketomycolic acid (Keto-MA), and artificially obtained deoxo-mycolic acid (deoxo-MA) from Mycobacterium bovis BCG were obtained by thermodynamic analysis of the surface pressure (pi) vs. average molecular area (A) isotherms. At lower temperatures and lower surface pressures, both Keto- and MeO-MAs formed rigid condensed monolayers where each MA molecule was considered to be in a 4-chain form, in which the three carbon chain segments due to bending of the 3-hydroxy aliphatic carboxylate chain and the 2-side chain were in compact parallel arrangement. At higher temperatures and surface pressures, MeO-MA and deoxo-MA tended to take stretched-out conformations in which the 3-hydroxy aliphatic carboxylate chain was more or less in an extended form, but Keto-MA retained the original 4-chain structure. The thickness measurement of the monolayers in situ by ellipsometry at different pi values and temperatures supported the above conclusions derived from the phase diagrams. The enthalpy changes associated with the phase transitions of MeO-MA and deoxo-MA implied that the MeO-MA needed larger energy to change from a compact conformation to an extended one, possibly and partly due to the dehydration of the methoxy group from water surface involved. Molecular dynamics studies of MA models derived from Monte Carlo calculations were also performed, which confirmed the conformational behavior of MAs suggested by the thermodynamic studies on the Langmuir monolayers.     

Aggregatibacter actinomycetemcomitans induces detachment and death of human gingival epithelial cells and fibroblasts via elastase release following leukotoxin‐dependent neutrophil lysis

Aggregatibacter actinomycetemcomitans is considered to be associated with periodontitis. Leukotoxin (LtxA), which destroys leukocytes in humans, is one of this bacterium's major virulence factors. Amounts of neutrophil elastase (NE), which is normally localized in the cytoplasm of neutrophils, are reportedly increased in the saliva of patients with periodontitis. However, the mechanism by which NE is released from human neutrophils and the role of NE in periodontitis is unclear. In the present study, it was hypothesized that LtxA induces NE release from human neutrophils, which subsequently causes the breakdown of periodontal tissues. LtxA‐treatment did not induce significant cytotoxicity against human gingival epithelial cells (HGECs) or human gingival fibroblasts (HGFs). However, it did induce significant cytotoxicity against human neutrophils, leading to NE release. Furthermore, NE and the supernatant from LtxA‐treated human neutrophils induced detachment and death of HGECs and HGFs, these effects being inhibited by administration of an NE inhibitor, sivelestat. The present results suggest that LtxA mediates human neutrophil lysis and induces the subsequent release of NE, which eventually results in detachment and death of HGECs and HGFs. Thus, LtxA‐induced release of NE could cause breakdown of periodontal tissue and thereby exacerbate periodontitis.     

Seasonal change in xylem growth of <Emphasis Type="Italic">Pinus densiflora</Emphasis> in central Japan

This study investigated the seasonal change in xylem growth of Japanese red pine (Pinus densiflora). Wood cores were sampled at 2-week intervals from April to November in 2012 using the microcoring method. Daily increment rates of tracheid number and tree-ring width were compared with seasonal changes in daily mean temperature and photoperiod. Xylem growth started in early to late May and stopped in late October to early November. The maximum daily increment rates of tracheid number and tree-ring width were in early July. The 95 % confidence intervals of the timing of the maximum daily increment rates included the summer solstice (23 June) with the longest photoperiod, but not the warmest day (30 July). The maximum daily increment rate of xylem growth is thought to be controlled by the photoperiod rather than by temperature. The daily mean temperature exceeded 20 °C after the summer solstice, indicating that temperature is not a limiting factor for xylem growth. This study suggests that the timing of maximum daily increment rates of xylem growth of P. densiflora is controlled by the photoperiod.     

Improvement of neural stem cell survival in collagen hydrogels by incorporating laminin-derived cell adhesive polypeptides

Cell transplantation is a potential methodology for the treatment of Parkinson's disease. However, the therapeutic effect is limited by poor viability of transplanted cells. To overcome this problem, we hypothesized that a dual step approach, whereby providing an adhesive substrate for transplanted cells and, at the same time, by preventing the infiltration of activated microglia into the site of transplantation promotes the cell survival. To establish above conditions, attempts were made to prepare 3-D matrices using collagen hydrogels that incorporated integrin-binding polypeptides derived from laminin-1. Tandem combinations of laminin globular domains as well as a single globular domain 3 were prepared using recombinant DNA technology as a fusion with hexahistidine and bound to metal chelated surfaces to screen for the adhesion and proliferation of neural stem cells (NSCs). In addition, a small peptide derived from laminin γ1 chain was prepared and heterodimerized with the globular domain-containing chimeric proteins to evaluate for the enhancement of integrin-mediated cell adhesion. As a result, a heterodimer consisting of the globular domain 3 of the laminin α1 chain and the peptide from the laminin γ1 chain was selected as the best candidate among the polypeptides studied here for the incorporation into a collagen hydrogel. It was shown that the survival of NSCs was indeed promoted in the collagen hydrogel incorporating the heterodimer compared to the pure collagen hydrogel.