Comparison of DNA sequences required for the function of citrate utilization among different citrate utilization plasmids

The relatedness of DNA sequences encoding citrate utilization was examined by hybridization with a cloned DNA fragment from a citrate utilization (Cit) plasmid, pOH30221, and DNA of other Cit plasmids. This revealed that there are at least two groups of Cit plasmids: the Inc W Cit plasmids, which show homology with the probe, and the Inc H1 plasmids, which do not.     

How mosquitoes fly to man

1. A model is presented to estimate the mosquito density and radius (r) of the attraction range of man as the bait.
2. Man walked to a spot in the woods and sampled mosquitoes flying to him with a net continuously. The arrival pattern was constant in each mosquito species, and in all species, the number of mosquitoes sampled per five min became constant after ten minutes sampling.
3. The mosquitoes gathered to man were composed of D: those waiting alight, I: those intruding the attraction range and F: those following man to the spot. They were estimated by means of continuous sampling sets and densities of D and I were calculated.
4. r s of female and male of A. albopictus and A. japonicus were 4.0, 5.6 and 9.0 m respectively. In these species, most individuals were D, although, in T. bambusa all individuals were I, flying to search for hosts.
5. How mosquitoes and hosts encounter, is discussed.

     

Synthesis and biological activity of O-(N-acetyl-β-muramoyl-l-alanyl-d-isoglutamine)-(1→6)-2-acylamino-2-deoxy-d-glucoses

Benzoylation of benzyl 2-acetamido-2-deoxy-4,6-O-isopropylidene-α-d-glucopyranoside, benzyl 2-deoxy-2-(dl-3-hydroxytetradecanoylamino)-4,6-O-isopropylidene-α-d-glucopyranoside, and benzyl 2-deoxy-4,6-O-isopropylidene-2-octadecanoylamino-β-d-glucopyranoside, with subsequent hydrolysis of the 4,6-O-isopropylidene group, gave the corresponding 3-O-benzoyl derivatives (4, 5, and 7). Hydrogenation of benzyl 2-acetamido-4,6-di-O-acetyl-2-deoxy-3-O-[d-1-(methoxycarbonyl)ethyl]-α-d-glucopyranoside, followed by chlorination, gave a product that was treated with mercuric actate to yield 2-acetamido-1,4,6-tri-O-acetyl-2-deoxy-3-O-[d-1-(methoxycarbonyl)ethyl]-β-d-glucopyranose (11). Treatment of 11 with ferric chloride afforded the oxazoline derivative, which was condensed with 4, 5, and 7 to give the (1→6)-β-linked disaccharide derivatives 13, 15, and 17. Hydrolysis of the methyl ester group in the compounds derived from 13, 15, and 17 by 4-O-acetylation gave the corresponding free acids, which were coupled with l-alanyl-d-isoglutamine benzyl ester, to yield the dipeptide derivatives 19–21 in excellent yields. Hydrolysis of 19–21, followed by hydrogenation, gave the respective O-(N-acetyl-β-muramoyl-l-alanyl-d-isoglutamine)-(1→6)-2-acylamino-2-deoxy-d-glucoses in good yields. The immunoadjuvant activity of these compounds was examined in guinea-pigs.     

Synthesis and biological activity of O-(N-acetyl-β-muramoyl-l-alanyl-d-isoglutamine)-(1→6)-2-acylamino-2-deoxy-d-glucoses

Benzoylation of benzyl 2-acetamido-2-deoxy-4,6-O-isopropylidene-α-d-glucopyranoside, benzyl 2-deoxy-2-(dl-3-hydroxytetradecanoylamino)-4,6-O-isopropylidene-α-d-glucopyranoside, and benzyl 2-deoxy-4,6-O-isopropylidene-2-octadecanoylamino-β-d-glucopyranoside, with subsequent hydrolysis of the 4,6-O-isopropylidene group, gave the corresponding 3-O-benzoyl derivatives (4, 5, and 7). Hydrogenation of benzyl 2-acetamido-4,6-di-O-acetyl-2-deoxy-3-O-[d-1-(methoxycarbonyl)ethyl]-α-d-glucopyranoside, followed by chlorination, gave a product that was treated with mercuric actate to yield 2-acetamido-1,4,6-tri-O-acetyl-2-deoxy-3-O-[d-1-(methoxycarbonyl)ethyl]-β-d-glucopyranose (11). Treatment of 11 with ferric chloride afforded the oxazoline derivative, which was condensed with 4, 5, and 7 to give the (1→6)-β-linked disaccharide derivatives 13, 15, and 17. Hydrolysis of the methyl ester group in the compounds derived from 13, 15, and 17 by 4-O-acetylation gave the corresponding free acids, which were coupled with l-alanyl-d-isoglutamine benzyl ester, to yield the dipeptide derivatives 19–21 in excellent yields. Hydrolysis of 19–21, followed by hydrogenation, gave the respective O-(N-acetyl-β-muramoyl-l-alanyl-d-isoglutamine)-(1→6)-2-acylamino-2-deoxy-d-glucoses in good yields. The immunoadjuvant activity of these compounds was examined in guinea-pigs.     

A novel NE-dlg/SAP102-associated protein, p51-nedasin, related to the amidohydrolase superfamily, interferes with the association between NE-dlg/SAP102 and N-methyl-D-aspartate receptor.

The membrane-associated guanylate kinase proteins have been known to interact various membrane receptors with their N-terminal segments designated the PDZ domains and to cluster these receptors at the target site of the cell membrane. NE-dlg/SAP102, a neuronal and endocrine tissue-specific MAGUK family protein, was found to be expressed in both dendrites and cell bodies in neuronal cells. Although NE-dlg/SAP102 localized at dendrites was shown to interact with N-methyl-D-aspartate receptor 2B via the PDZ domains to compose postsynaptic density, the binding proteins existing in the cell body of the neuron are still unknown. Here we report the isolation of a novel NE-dlg/SAP102-associated protein, p51-nedasin. Nedasin has a significant homology with amidohydrolase superfamily proteins and shows identical sequences to a recently identified protein that has guanine aminohydrolase activity. Nedasin has four alternative splice variants (S, V1, V2, and V3) that exhibited different C-terminal structures. NE-dlg/SAP102 is shown to interact with only the S form of nedasin which is predominantly expressed in brain. The expression of nedasin in neuronal cells increases in parallel with the progress of synaptogenesis and is mainly detected in cell bodies where it co-localizes with NE-dlg/SAP102. Furthermore, nedasin interferes with the association between NE-dlg/SAP102 and NMDA receptor 2B in vitro. These findings suggest that alternative splicing of nedasin may play a role in the formation and/or structural change in synapses during neuronal development by modifying clustering of neurotransmitter receptors at the synaptic sites.     

Silver(I) tetraiodoethylene complexes with twisted olefin moiety

The reactions of silver perchlorate and tetraiodoethylene in different solvents, namely, benzene and toluene, isolated two silver(I)–iodocarbon complexes, [Ag(C₂I₄)(C₆H₆)₂(ClO₄)] (1) and [Ag(C₂I₄)(ClO₄)] (2). Both compounds contain intact iodoalkenes which coordinate via σ-donation of a halogen lone pair and retain their carbon–iodine bonds. Owing to the participation of the benzene molecules in coordination, complex 1 is found to be a discrete monomer in which the five-coordinate geometry of the silver ion is comprised of two benzene molecules, one C₂I₄ group and one perchlorate ion. In contrast, the unsaturated coordination environment of the metal ion in 2 is filled by the second iodocarbon group leading to a two-dimensional framework. The coordinated tetraiodoethylene molecules involve severe twisting of the C=C double bond, causing the C=C stretching band to move to a lower frequency.     

Spectral tuning in salamander visual pigments studied with dihydroretinal chromophores.

In visual pigments, opsin proteins regulate the spectral absorption of a retinal chromophore by mechanisms that change the energy level of the excited electronic state relative to the ground state. We have studied these mechanisms by using photocurrent recording to measure the spectral sensitivities of individual red rods and red (long-wavelength-sensitive) and blue (short-wavelength-sensitive) cones of salamander before and after replacing the native 3-dehydro 11-cis retinal chromophore with retinal analogs: 11-cis retinal, 3-dehydro 9-cis retinal, 9-cis retinal, and 5,6-dihydro 9-cis retinal. The protonated Schiff's bases of analogs with unsaturated bonds in the ring had broader spectra than the same chromophores bound to opsins. Saturation of the bonds in the ring reduced the spectral bandwidths of the protonated Schiff's bases and the opsin-bound chromophores and made them similar to each other. This indicates that torsion of the ring produces spectral broadening and that torsion is limited by opsin. Saturating the 5,6 double bond in retinal reduced the perturbation of the chromophore by opsin in red and in blue cones but not in red rods. Thus an interaction between opsin and the chromophoric ring shifts the spectral maxima of the red and blue cone pigments, but not that of the red rod pigment.     

Characterization of a novel 3-hydroxybutyrate dehydrogenase from <Emphasis Type="Italic">Ralstonia pickettii</Emphasis> T1

We previously reported that the activities of two 3-hydroxybutyrate dehydrogenases (BDH1 and BDH2) were greatly influenced by culture conditions when Ralstonia pickettii T1, a strain growing on extracellular poly-3-hydroxybutyrate (PHB), was grown on different carbon sources such as 3HB and succinate. In this study, knockout mutants of bdh1 or bdh2 were constructed and characterized under different culture conditions. In addition, a novel BDH (BDH3) was found in bdh2 mutants, and bdh3 was cloned. Apparent kinetic parameters for the substrates of BDH3 indicated that the enzyme is suitable for the oxidation reaction of 3-hydroxybutyrate (3HB) to acetoacetate. In Western blotting, it was clear that BDH3 is produced only in cells grown on 3HB or PHB as a carbon source, while BDH1 and BDH2 are produced in cells grown on various carbon sources such as sugars, amino acids, organic acids, 3HB, and PHB. Both the bdh1 and bdh2 mutants lagged behind the wild type in growth rates when the cells were cultured with 3HB, citrate, succinate, or nutrient broth. A test of sensitivity to diamide as an oxidative stress revealed that the lack of BDH1 or BDH2 caused a decline in the capacity to neutralize the stress. These results suggested that BDH1 and BDH2 are needed to regulate the cytoplasmic redox state as well as to utilize 3HB, while BDH3 is specialized to utilize 3HB. The expression of bdh3 may be coordinately regulated with a gene encoding putative 3HB permease.     

A New Mouse Allele of Glutamate Receptor Delta 2 with Cerebellar Atrophy and Progressive Ataxia

Spinocerebellar degenerations (SCDs) are a large class of sporadic or hereditary neurodegenerative disorders characterized by progressive motion defects and degenerative changes in the cerebellum and other parts of the CNS. Here we report the identification and establishment from a C57BL/6J mouse colony of a novel mouse line developing spontaneous progressive ataxia, which we refer to as ts3. Frequency of the phenotypic expression was consistent with an autosomal recessive Mendelian trait of inheritance, suggesting that a single gene mutation is responsible for the ataxic phenotype of this line. The onset of ataxia was observed at about three weeks of age, which slowly progressed until the hind limbs became entirely paralyzed in many cases. Micro-MRI study revealed significant cerebellar atrophy in all the ataxic mice, although individual variations were observed. Detailed histological analyses demonstrated significant atrophy of the anterior folia with reduced granule cells (GC) and abnormal morphology of cerebellar Purkinje cells (PC). Study by ultra-high voltage electron microscopy (UHVEM) further indicated aberrant morphology of PC dendrites and their spines, suggesting both morphological and functional abnormalities of the PC in the mutants. Immunohistochemical studies also revealed defects in parallel fiber (PF)–PC synapse formation and abnormal distal extension of climbing fibers (CF). Based on the phenotypic similarities of the ts3 mutant with other known ataxic mutants, we performed immunohistological analyses and found that expression levels of two genes and their products, glutamate receptor delta2 (grid2) and its ligand, cerebellin1 (Cbln1), are significantly reduced or undetectable. Finally, we sequenced the candidate genes and detected a large deletion in the coding region of the grid2 gene. Our present study suggests that ts3 is a new allele of the grid2 gene, which causes similar but different phenotypes as compared to other grid2 mutants.