Bullera hoabinhensis sp. nov., a new ballistoconidiogenous yeast isolated from a plant leaf collected in Vietnam

VY-68, a ballistoconidiogenous yeast strain, isolated from a plant leaf at Cuc Phuong National Park of Ninh Binh Province, Vietnam, was assigned to the genus Bullera based on morphological and chemotaxonomical characteristics. Based on the sequence analyses of 18S rDNA, D1/D2 region of 26S rDNA, and internal transcribed spacer regions (ITS), VY-68 was phylogenetically closely related to Bullera pseudoalba and Cryptococcus cellulolyticus. DNA-DNA reassociation experiments among VY-68, B. pseudoalba and C. cellulolyticus revealed that strain VY-68 is a distinct species, and the latter two are conspecific. Bullera hoabinhensis is proposed for VY-68.     

In vitro resistance studies of hepatitis C virus serine protease inhibitors, VX-950 and BILN 2061: structural analysis indicates different resistance mechanisms

We have used a structure-based drug design approach to identify small molecule inhibitors of the hepatitis C virus (HCV) NS3.4A protease as potential candidates for new anti-HCV therapies. VX-950 is a potent NS3.4A protease inhibitor that was recently selected as a clinical development candidate for hepatitis C treatment. In this report, we describe in vitro resistance studies using a subgenomic replicon system to compare VX-950 with another HCV NS3.4A protease inhibitor, BILN 2061, for which the Phase I clinical trial results were reported recently. Distinct drug-resistant substitutions of a single amino acid were identified in the HCV NS3 serine protease domain for both inhibitors. The resistance conferred by these mutations was confirmed by characterization of the mutant enzymes and replicon cells that contain the single amino acid substitutions. The major BILN 2061-resistant mutations at Asp(168) are fully susceptible to VX-950, and the dominant resistant mutation against VX-950 at Ala(156) remains sensitive to BILN 2061. Modeling analysis suggests that there are different mechanisms of resistance to VX-950 and BILN 2061.     

Kinetic and Structural Insights into the Mechanism of AMPylation by VopS Fic Domain

The bacterial pathogen Vibrio parahemeolyticus manipulates host signaling pathways during infections by injecting type III effectors into the cytoplasm of the target cell. One of these effectors, VopS, blocks actin assembly by AMPylation of a conserved threonine residue in the switch 1 region of Rho GTPases. The modified GTPases are no longer able to interact with downstream effectors due to steric hindrance by the covalently linked AMP moiety. Herein we analyze the structure of VopS and its evolutionarily conserved catalytic residues. Steady-state analysis of VopS mutants provides kinetic understanding on the functional role of each residue for AMPylation activity by the Fic domain. Further mechanistic analysis of VopS with its two substrates, ATP and Cdc42, demonstrates that VopS utilizes a sequential mechanism to AMPylate Rho GTPases. Discovery of a ternary reaction mechanism along with structural insight provides critical groundwork for future studies for the family of AMPylators that modify hydroxyl-containing residues with AMP.     

The Sodium Bicarbonate Cotransporter (NBCe1) Is Essential for Normal Development of Mouse Dentition

Proximal renal tubular acidosis (pRTA) is a syndrome caused by abnormal proximal tubule reabsorption of bicarbonate resulting in metabolic acidosis. Patients with mutations to the SLC4A4 gene (coding for the sodium bicarbonate cotransporter NBCe1), have pRTA, growth delay, ocular defects, and enamel abnormalities. In an earlier report, we provided the first evidence that enamel cells, the ameloblasts, express NBCe1 in a polarized fashion, thereby contributing to trans-cellular bicarbonate transport. To determine whether NBCe1 plays a critical role in enamel development, we studied the expression of NBCe1 at various stages of enamel formation in wild-type mice and characterized the biophysical properties of enamel in NBCe1^−/− animals. The enamel of NBCe1^−/− animals was extremely hypomineralized and weak with an abnormal prismatic architecture. The expression profile of amelogenin, a known enamel-specific gene, was not altered in NBCe1^−/− animals. Our results show for the first time that NBCe1 expression is required for the development of normal enamel. This study provides a mechanistic model to account for enamel abnormalities in certain patients with pRTA.     

Hormonal stimulation of maturation and ovulation of oocytes in Zebrasoma scopas (Acanthuridae)

The experiments were carried out on hormonal stimulation of oocyte maturation in Zebrasoma scopas from the South China Sea, Vietnam. Three variants of surfagon injections were studied: 1—double injections (5 + 20 μg/kg of fish body weight); 2—double injections (2 + 8 μg/kg); and 3—single injections (20 μg/kg). The time interval between two injections comprised 15–24 h. Ovulation of oocytes in variants 1 and 2 was observed in most (67%) females 33–47 h after the first injection. The increase of the time interval between injections I and II was followed by the decrease of the interval between injection II and ovulation. In variant 3, oocytes ripened but ovulation was absent. The oocytes possessed with the competence for maturation are always present in the ovaries because of a continuous type of oogenesis. The morphological changes in oocytes in the process of maturation were observed. Ovulated oocytes could be stored in the ovary cavity no more than 4 h; the number of embryos with normal cleavage decreased during this time from 90 to 53%.     

Diversity of wild and cultivated pearl millet accessions (Pennisetum glaucum [L.] R. Br.) in Niger assessed by microsatellite markers

Genetic diversity of crop species in sub-Sahelian Africa is still poorly documented. Among such crops, pearl millet is one of the most important staple species. In Niger, pearl millet covers more than 65% of the total cultivated area. Analyzing pearl millet genetic diversity, its origin and its dynamics is important for in situ and ex situ germplasm conservation and to increase knowledge useful for breeding programs. We developed new genetic markers and a high-throughput technique for the genetic analysis of pearl millet. Using 25 microsatellite markers, we analyzed genetic diversity in 46 wild and 421 cultivated accessions of pearl millet in Niger. We showed a significantly lower number of alleles and lower gene diversity in cultivated pearl millet accessions than in wild accessions. This result contrasts with a previous study using iso-enzyme markers showing similar genetic diversity between cultivated and wild pearl millet populations. We found a strong differentiation between the cultivated and wild groups in Niger. Analyses of introgressions between cultivated and wild accessions showed modest but statistically supported evidence of introgressions. Wild accessions in the central region of Niger showed introgressions of cultivated alleles. Accessions of cultivated pearl millet showed introgressions of wild alleles in the western, central, and eastern parts of Niger.Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.Cedric Mariac and Viviane Luong have contributed equally to this work.     

Loss of P4 ATPases Drs2p and Dnf3p disrupts aminophospholipid transport and asymmetry in yeast post-Golgi secretory vesicles

Eukaryotic plasma membranes generally display asymmetric lipid distributions with the aminophospholipids concentrated in the cytosolic leaflet. This arrangement is maintained by aminophospholipid translocases (APLTs) that use ATP hydrolysis to flip phosphatidylserine (PS) and phosphatidylethanolamine (PE) from the external to the cytosolic leaflet. The identity of APLTs has not been established, but prime candidates are members of the P4 subfamily of P-type ATPases. Removal of P4 ATPases Dnf1p and Dnf2p from budding yeast abolishes inward translocation of 6-[(7-nitrobenz-2-oxa-1,3-diazol-4-yl)aminocaproyl] (NBD)-labeled PS, PE, and phosphatidylcholine (PC) across the plasma membrane and causes cell surface exposure of endogenous PE. Here, we show that yeast post-Golgi secretory vesicles (SVs) contain a translocase activity that flips NBD-PS, NBD-PE, and NBD-PC to the cytosolic leaflet. This activity is independent of Dnf1p and Dnf2p but requires two other P4 ATPases, Drs2p and Dnf3p, that reside primarily in the trans-Golgi network. Moreover, SVs have an asymmetric PE arrangement that is lost upon removal of Drs2p and Dnf3p. Our results indicate that aminophospholipid asymmetry is created when membrane flows through the Golgi and that P4-ATPases are essential for this process.     

In vitro antiviral activity of sulfated Auricularia auricula polysaccharides

Total Auricularia auricula polysaccharide (AAP(t)) was prepared by extracting and removing the proteins. Column chromatography was used to further graded it into AAP(1) and AAP(2). Three AAPs were modified by chlorosulfonic acid-pyridine method to obtain three sulfated AAPs (sAAPs), sAAP(t), sAAP(1) and sAAP(2), respectively. Three sAAPs and Newcastle disease virus (NDV) were added into cultivation system of chicken embryo fibroblast (CEF) in three manners, pre-, post- and simultaneous-adding polysaccharide with NDV respectively, taking three non-modified AAPs as control. Their anti-viral activities were compared by MTT method. The results showed that sAAPs and AAPs at a certain concentration could significantly inhibit the cellular infectivity of NDV in three manners. The effects of sAAPs were better than that of AAPs. It indicated that sulfated modification could enhance the antiviral activity of AAP. sAAP(1) and sAAP(t) possessed stronger activity and would be as the component of a new-type antiviral drug.     

Genome Sequence of “Candidatus Microthrix parvicella” Bio17-1, a Long-Chain-Fatty-Acid-Accumulating Filamentous Actinobacterium from a Biological Wastewater Treatment Plant

“Candidatus Microthrix” bacteria are deeply branching filamentous actinobacteria which occur at the water-air interface of biological wastewater treatment plants, where they are often responsible for foaming and bulking. Here, we report the first draft genome sequence of a strain from this genus: “Candidatus Microthrix parvicella” strain Bio17-1.     

Xanthine oxidase inhibitory activity of constituents of Cinnamomum cassia twigs

A methanol extract of the twigs of Cinnamomum cassia was found to inhibit xanthine oxidase. Purification of the methanol extract afforded three new phenolic glycosides, cinnacasolide A-C (11-13), together with 10 known compounds (1-10). The structures of the three new compounds were determined by interpretation of spectroscopic data. Cinnamaldehyde derivatives 1-5 and 7 were significant inhibitors of xanthine oxidase, with IC(50) values ranging from 7.8 to 36.3 μg/mL. The results indicate that the acyl group of these cinnamaldehyde derivatives plays an important role in the inhibition of xanthine oxidase.