Multi-scale architecture of archaeal chromosomes

1. Download : Download high-res image (109KB)
2. Download : Download full-size image

     

Synthesis of Chiral NADH Model Compounds Containing a Sulfur Atom and Their Asymmetric Reduction

Oryzalexins A, B and C were isolated as a group of novel phytoalexins from rice (Oryza sativa) blast leaves infected with Pyricularia oryzae. The basis of the structures of Oryzalexins A, B and C was laid by spectroscopic methods and their inhibitory activities against spore germination and germ tube growth of P. oryzae were assayed.

Oryzalexins A, B and C, isolated from rice leaves infected with P. oryzae as a group of novel phytoalexins, were confirmed to be (+)-sandaracopimaradiene derivatives by chemical and spectroscopic studies, i.e. A: 3-oxy-7-oxo- (I); B: 3-oxo-7-oxy- (II) and C: 3,7-dioxo-(+)-sandaracopimaradiene (III).     

Constructing an improved pyrroloquinoline quinone glucose dehydrogenase binding aptamer for enzyme labeling

Motif analysis of PGa4 indicated that eight consecutive guanine residues were most important for pyrroloquinoline quinine glucose dehydrogenase (PQQGDH) recognition. Because the truncated mutants minimized unexpected interactions between PGa4 and the target-binding aptamer, they will now facilitate the construction of a highly sensitive detection system using a PQQGDH-labeled diagnostic marker-binding aptamer.     

Improvement of compactin (ML-236B) production by genetic engineering in compactin high-producing <Emphasis Type="Italic">Penicillium citrinum</Emphasis>

An increase in compactin (ML-236B) production was achieved by introducing a whole compactin biosynthetic gene cluster or the regulatory gene mlcR into compactin high-producing Penicillium citrinum. In the previous report, we introduced mlcR encoding the positive regulator of compactin biosynthetic genes into compactin high-producing strain no. 41520, and most of the transformants produced higher amounts of compactin. Here, we characterize one of the resulting high producers (strain TIR-35, which produced 50% more compactin) and reveal that TIR-35 contained five copies of mlcR and that early, enhanced expression of mlcR caused compactin overproduction. Similarly, the introduction of mlcR into strain T48.19, which was created previously from strain no. 41520 by introducing a partial compactin biosynthetic gene cluster, enhanced compactin production further. Our results indicated that genetic engineering is an effective tool to improve compactin production, even in compactin high producers.     

Identification of genes encoding photoconvertible (Class I) water-soluble chlorophyll-binding proteins from Chenopodium ficifolium

Photoconvertible water-soluble chlorophyll-binding proteins, called Class I WSCPs, have been detected in Chenopodiaceae, Amaranthaceae and Polygonaceae plant species. To date, Chenopodium album WSCP (CaWSCP) is the only cloned gene encoding a Class I WSCP. In this study, we identified two cDNAs encoding Chenopodium ficifolium Class I WSCPs, CfWSCP1, and CfWSCP2. Sequence analyses revealed that the open reading frames of CfWSCP1 and CfWSCP2 were 585 and 588 bp, respectively. Furthermore, both CfWSCPs contain cystein2 and cystein30, which are essential for the chlorophyll-binding ability of CaWSCP. Recombinant CfWSCP1 and CfWSCP2, expressed in Escherichia coli as hexa-histidine fusion proteins (CfWSCP1-His and CfWSCP2-His), formed inclusion bodies; however, we were able to solubilize these using a buffer containing 8 M urea and then refold them by dialysis. The refolded CfWSCP1-His and CfWSCP2-His could bind chlorophylls and exhibited photoconvertibility, confirming that the cloned CfWSCPs are further examples of Class I WSCPs.     

Brain Swelling and Loss of Gray and White Matter Differentiation in Human Postmortem Cases by Computed Tomography

The purpose of this study was to evaluate the brain by postmortem computed tomography (PMCT) versus antemortem computed tomography (AMCT) using brains from the same patients. We studied 36 nontraumatic subjects who underwent AMCT, PMCT, and pathological autopsy in our hospital between April 2009 and December 2013. PMCT was performed within 20 h after death, followed by pathological autopsy including the brain. Autopsy confirmed the absence of intracranial disorders that might be related to the cause of death or might affect measurements in our study. Width of the third ventricle, width of the central sulcus, and attenuation in gray matter (GM) and white matter (WM) from the same area of the basal ganglia, centrum semiovale, and high convexity were statistically compared between AMCT and PMCT. Both the width of the third ventricle and the central sulcus were significantly shorter in PMCT than in AMCT (P < 0.0001). GM attenuation increased after death at the level of the centrum semiovale and high convexity, but the differences were not statistically significant considering the differences in attenuation among the different computed tomography scanners. WM attenuation significantly increased after death at all levels (P<0.0001). The differences were larger than the differences in scanners. GM/WM ratio of attenuation was significantly lower by PMCT than by AMCT at all levels (P<0.0001). PMCT showed an increase in WM attenuation, loss of GM–WM differentiation, and brain swelling, evidenced by a decrease in the size of ventricles and sulci.     

Analysis of functional regions of YPM, a superantigen derived from gram-negative bacteria.

The bacterial superantigens, staphylococcal enterotoxins and streptococcal pyrogenic exotoxins, are grouped in a family by the conservation of amino acid sequence and polypeptide folding patterns. In the case of Yersinia pseudotuberculosis-derived mitogen (YPM), however, there is no noticeable homology with this family, although many of the in vitro functional features conform to the criteria for a superantigen. To study the mode of action of YPM at the molecular level, we first generated a number of YPM point mutants with reduced T-cell proliferative activity using random mutagenesis and localized the amino acid positions involved in either major histocompatibility complex class II or T-cell receptor Vbeta-interaction. Plotting the elucidated positions on the hydrophilicity profile suggested that they reside mostly on the outer portion of the molecule. We also report that the two cysteines positioned almost at opposing ends of the YPM molecule are connected by an S-S bond the destruction of which causes fatal damage. Finally, we obtained evidence that YPM partially competes with staphylococcal enterotoxin E for human leukocyte antigen-DR binding. This raises the question of whether these different types of superantigens have acquired the same function by genetic convergence or originated from a common ancestral gene.     

Molecular genotyping of N-acetylation polymorphism to predict phenotype

Summary N-acetylation polymorphism is one of the representative pharmacogenetic traits that underlie interindividual and interethnic differences in response to xenobiotics. To develop a practical genotyping method to predict acetylator phenotype, we studied the conditions for accurate phenotyping, and identified the phenotype in 51 Japanese. Then we performed Southern blot analysis of genomic DNA from these subjects using ³²P-labeled cDNA for polymorphic N-acetyltransferase in the liver, and found that four N-acetyltransferase alleles generated six genotypes. The present genotyping method predicted the rapid, intermediate, and slow acetylators correctly in 48 of 51 overall subjects (96%) and in all of 4 slow acetylators.