Suppression of Vps13 adaptor protein mutants reveals a central role for PI4P in regulating prospore membrane extension.

Vps13 family proteins are proposed to function in bulk lipid transfer between membranes, but little is known about their regulation. During sporulation of Saccharomyces cerevisiae, Vps13 localizes to the prospore membrane (PSM) via the Spo71-Spo73 adaptor complex. We previously reported that loss of any of these proteins causes PSM extension and subsequent sporulation defects, yet their precise function remains unclear.

[The Position and Roles of Occupational Health and Safety Functions in the UK Risk Management System].

Studying the crisis management systems of other developed countries has been effective in clarifying what the position and roles of occupational health and safety functions should be in the crisis management system in Japan. In addition to previous studies on the US system, we studied the UK system. We gathered relevant information by visiting the headquarters of the Health and Safety Executive (HSE) and the Office for Nuclear Regulation (ONR), as well as obtaining information available via the internet.

Dynamic localization of a yeast development-specific PP1 complex during prospore membrane formation is dependent on multiple localization signals and complex formation.

During the developmental process of sporulation in , membrane structures called prospore membranes are formed de novo, expand, extend, acquire a round shape, and finally become plasma membranes of the spores. encodes a regulatory/targeting subunit of protein phosphatase type 1 that is required for sporulation. Gip1 recruits the catalytic subunit Glc7 to septin structures that form along the prospore membrane; however, the molecular basis of its localization and function is not fully understood.

The Dysferlin Domain-Only Protein, Spo73, Is Required for Prospore Membrane Extension in Saccharomyces cerevisiae.

Sporulation of Saccharomyces cerevisiae is a developmental process in which an ascus containing four haploid spores forms from a diploid cell. During this process, newly formed membrane structures called prospore membranes extend along the nuclear envelope and engulf and package daughter nuclei along with cytosol and organelles to form precursors of spores. Proteins involved in prospore membrane extension, Vps13 and Spo71, have recently been reported; however, the overall mechanism of membrane extension remains unclear.

Structural insight into photoactivation of an adenylate cyclase from a photosynthetic cyanobacterium.

Cyclic-AMP is one of the most important second messengers, regulating many crucial cellular events in both prokaryotes and eukaryotes, and precise spatial and temporal control of cAMP levels by light shows great promise as a simple means of manipulating and studying numerous cell pathways and processes. The photoactivated adenylate cyclase (PAC) from the photosynthetic cyanobacterium Oscillatoria acuminata (OaPAC) is a small homodimer eminently suitable for this task, requiring only a simple flavin chromophore within a blue light using flavin (BLUF) domain. These domains, one of the most studied types of biological photoreceptor, respond to blue light and either regulate the activity of an attached enzyme domain or change its affinity for a repressor protein.

Identification and characterization of transcriptional control region of the human beta 1,4-mannosyltransferase gene.

All asparagine-linked glycans (N-glycans) on the eukaryotic glycoproteins are primarily derived from dolichol-linked oligosaccharides (DLO), synthesized on the rough endoplasmic reticulum membrane. We have previously reported cloning and identification of the human gene, HMT-1, which encodes chitobiosyldiphosphodolichol beta-mannosyltransferase (β1,4-MT) involved in the early assembly of DLO. Considering that N-glycosylation is one of the most ubiquitous post-translational modifications for many eukaryotic proteins, the HMT-1 could be postulated as one of the housekeeping genes, but its transcriptional regulation remains to be investigated.

Identification of photoactivated adenylyl cyclases in Naegleria australiensis and BLUF-containing protein in Naegleria fowleri.

Complete genome sequencing of Naegleria gruberi has revealed that the organism encodes polypeptides similar to photoactivated adenylyl cyclases (PACs). Screening in the N. australiensis genome showed that the organism also encodes polypeptides similar to PACs.

Involvement of glutamate 97 in ion influx through photo-activated channelrhodopsin-2.

The light absorption of a channelrhodopsin-2 (ChR2) is followed by conformational changes to the molecule, which allows the channel structure to become permeable to cations. Previously, a single point mutation in ChR2, which replaces glutamate residue 97 with a nonpolar alanine (E97A), was found to attenuate the photocurrent, suggesting that the E97 residue is involved in ion flux regulation. Here, the significance of E97 and its counterpart ChR1 (E136) were extensively studied by mutagenesis, whereby we replaced these glutamates with aspartate (D), glutamine (Q) or arginine (R).

Alg14 organizes the formation of a multiglycosyltransferase complex involved in initiation of lipid-linked oligosaccharide biosynthesis.

Protein N-glycosylation begins with the assembly of a lipid-linked oligosaccharide (LLO) on the endoplasmic reticulum (ER) membrane. The first two steps of LLO biosynthesis are catalyzed by a functional multienzyme complex comprised of the Alg7 GlcNAc phosphotransferase and the heterodimeric Alg13/Alg14 UDP-GlcNAc transferase on the cytosolic face of the ER. In the Alg13/14 glycosyltransferase, Alg14 recruits cytosolic Alg13 to the ER membrane through interaction between their C-termini.

Determination of dioxin concentrations in fish and seafood samples using a highly sensitive reporter cell line, DR-EcoScreen cells.

There is a strong need for the development of relatively rapid and low-cost bioassays for the determination of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and dioxin-like polychlorinated biphenyls (dl-PCBs) in environmental and food samples. In this study, we applied a reporter gene assay using DR-EcoScreen cells (DR-cell assay), which is highly sensitive to dioxins, to the determination of PCDD/Fs and dl-PCBs in fish and seafood samples. The PCDD/Fs and dl-PCBs were extracted from homogenated samples (10 g) of 30 fish and shellfish, purified by clean-up procedure using a multilayered silica gel column and an alumina column, and applied to DR-cell assay.

Blocking effect of NIP-142 on the KCNQ1/KCNE1 channel current expressed in HEK293 cells.

We examined the effect of NIP-142, a benzopyran compound with terminating effect on experimental atrial arrhythmia, on the KCNQ1/KCNE1 channel, which underlies the slow component of the cardiac delayed rectifier potassium channel (I(Ks)). NIP-142, as well as chromanol 293B, showed concentration-dependent blockade of the current expressed in HEK293 cells; the EC(50) value of NIP-142 and chromanol 293B for the inhibition of tail current was 13.2 µM and 4.

Differentiation of photocycle characteristics of flavin-binding BLUF domains of α- and β-subunits of photoactivated adenylyl cyclase of Euglena gracilis.

Photoactivated adenylyl cyclase (PAC), an FAD-containing photoreceptor of Euglena gracilis, appears to be a heterotetrameric structure composed of 2 homologous subunits (PACα and PACβ), each with a pair of BLUF domains (F1 and F2). PAC promotes blue light-induced activation of adenylyl cyclase. In our previous report, we demonstrated that a recombinant version of the PACαF2 domain displays blue light-induced photocycle similar to those of prokaryotic BLUFs (Ito et al.

Correct disulfide pairing is required for the biological activity of crustacean androgenic gland hormone (AGH): synthetic studies of AGH.

Androgenic gland hormone (AGH) of the woodlouse, Armadillidium vulgare, is a heterodimeric glycopeptide. In this study, we synthesized AGH with a homogeneous N-linked glycan using the expressed protein ligation method. Unexpectedly, disulfide bridge arrangement of a semisynthetic peptide differed from that of a recombinant peptide prepared in a baculovirus expression system, and the semisynthetic peptide showed no biological activity in vivo.

Acute impact of right ventricular infarction on early hemodynamic course after inferior myocardial infarction.

Background: Right ventricular myocardial infarction (RVMI) is the major cause of hypotension and/or shock (HpS) after acute inferior myocardial infarction (inferior AMI). It is, however, unclear how RVMI affects the acute hemodynamic course.

Methods And Results: In the present study, 153 patients with inferior AMI caused by right coronary artery occlusion were examined.

Protein phosphatase type 1-interacting protein Ysw1 is involved in proper septin organization and prospore membrane formation during sporulation.

Sporulation of Saccharomyces cerevisiae is a developmental process in which four haploid spores are generated inside a diploid cell. Gip1, a sporulation-specific targeting subunit of protein phosphatase type 1, together with its catalytic subunit, Glc7, colocalizes with septins along the extending prospore membrane and is required for septin organization and spore wall formation. However, the mechanism by which Gip1-Glc7 phosphatase promotes these events is unclear.

Photocurrent attenuation by a single polar-to-nonpolar point mutation of channelrhodopsin-2.

Channelrhodopsin-2 (ChR2), one of the algal light-gated cation channel rhodopsins, contains five peculiar glutamic acid residues in the N-terminal region corresponding to the second to third transmembrane helices. Here we made systematic mutations of these polar amino acid residues of ChR2 into nonpolar alanine, and evaluated their photocurrent properties. Amongst them, the photocurrent generated by the E97A mutation, ChR2(E97A), was much smaller than expected from its expression.

Comparative study on the nuclear hormone receptor activity of various phytochemicals and their metabolites by reporter gene assays using Chinese hamster ovary cells.

Phytochemicals are naturally present in a wide variety of plants, and have been suggested to exert a number of effects beneficial to human health. Several phytochemicals possess estrogenic activity through estrogen receptor alpha (ERalpha) and ERbeta, and are, therefore, termed phytoestrogens. In this study, we examined whether various phytochemicals have agonistic and/or antagonistic activity against six human nuclear receptors (ERalpha, ERbeta, androgen receptor (AR), glucocorticoid receptor (GR), thyroid hormone receptor alpha(1) (TRalpha(1)) and TRbeta(1)) by in vitro reporter gene assays using Chinese hamster ovary cells.

Molecular determinants differentiating photocurrent properties of two channelrhodopsins from chlamydomonas.

A light signal is converted into an electrical one in a single molecule named channelrhodopsin, one of the archaea-type rhodopsins in unicellular green algae. Although highly homologous, two molecules of this family, channelrhodopsin-1 (ChR1) and -2 (ChR2), are distinct in photocurrent properties such as the wavelength sensitivity, desensitization, and turning-on and -off kinetics. However, the structures regulating these properties have not been completely identified.

High current density in light-emitting transistors of organic single crystals.

We measured the external electroluminescence quantum efficiency (eta(ext)) in light-emitting field-effect transistors (LETs) made of organic single crystals and found that, in the ambipolar transport region, eta(ext) is not degraded up to several hundreds A/cm(2) current-density range, which is 2 orders of magnitude larger than that achieved in conventional organic light-emitting diodes. The present result indicates the single-crystal organic LET is a promising device structure that is free from various kinds of nonradiative losses such as exciton dissociation near electrodes and exciton annihilations.

Structural study of single-walled carbon nanotube films doped by a solution method.

Herein, we have studied a structure of SWNT films doped by organic molecules. In this study, we reacted organic molecules with SWNT films by a vapor phase and a liquid phase, respectively. The structure of doped SWNT films was investigated using synchrotron X-ray powder diffraction measurements, and we found the clear difference between the vapor phase reaction (v-doped) and the liquid phase reaction (I-doped).

In vitro screening of 200 pesticides for agonistic activity via mouse peroxisome proliferator-activated receptor (PPAR)alpha and PPARgamma and quantitative analysis of in vivo induction pathway.

Peroxisome proliferator-activated receptors (PPARs) are ligand-dependent transcription factors and key regulators of lipid metabolism and cell differentiation. However, there have been few studies reporting on a variety of environmental chemicals, which may interact with these receptors. In the present study, we characterized mouse PPARalpha and PPARgamma agonistic activities of 200 pesticides (29 organochlorines, 11 diphenyl ethers, 56 organophosphorus pesticides, 12 pyrethroids, 22 carbamates, 11 acid amides, 7 triazines, 8 ureas and 44 others) by in vitro reporter gene assays using CV-1 monkey kidney cells.

Photocycle features of heterologously expressed and assembled eukaryotic flavin-binding BLUF domains of photoactivated adenylyl cyclase (PAC), a blue-light receptor in Euglena gracilis.

Photoactivated adenylyl cyclase (PAC) is a recently discovered blue-light photoreceptor that mediates photomovement in Euglena gracilis(Iseki et al., Nature, 2002, 415, 1047--1051). PAC appears to be a heterotetramer composed of two FAD-binding subunits (PACalpha and PACbeta).

Archaeal-type rhodopsins in Chlamydomonas: model structure and intracellular localization.

Phototaxis in the unicellular green alga Chlamydomonas reinhardtii is mediated by rhodopsin-type photoreceptor(s). Recent expressed sequence tag database from the Kazusa DNA Research Institute has provided the basis for unequivocal identification of two archaeal-type rhodopsins in it. Here we demonstrate that one is located near the eyespot, wherein the photoreceptor(s) has long been thought to be enriched, along with the results of bioinformatic analyses.

A blue-light-activated adenylyl cyclase mediates photoavoidance in Euglena gracilis.

Blue light regulates processes such as the development of plants and fungi and the behaviour of microbes. Two types of blue-light receptor flavoprotein have been identified: cryptochromes, which have partial similarity to photolyases, and phototropins, which are photoregulated protein kinases. The former have also been found in animals with evidence of essential roles in circadian rhythms.