Existence of a Common Glycoprotein Homologous to S-Glycoproteins in Two Self-incompatible Homozygotes of Brassica campestris

S-Glycoproteins (S-locus-specific glycoproteins) in Brassicaspecies are present only in stigmas and thought to play an importantrole in self-incompatibility system. The stigma extract containsalso several other glycoproteins reacting with the antiserumto S-glycoproteins, among which some glycoproteins from S₈S₈-and S₉S₉-homozygotes have the same pI value. Both of the glycoproteinswhich were tentatively termed NS₈- and NS₈S₉-glycoproteins,respectively, were isolated and analyzed. Those were revealedto be identical. Its amino acid sequence was homologous withthe S-glycoproteins in Brassica species. The NS-glycoproteinswere expressed at the same time and only in stigma as S-glycoproteins. (Received July 19, 1988; Accepted September 7, 1988)     

Novel inhibition mechanism of Bacillus cereus sphingomyelinase by beryllium fluoride

Phosphate analogs have been known to inhibit competitively various phosphatases and phospholipase C and D. We found for the first time that only beryllium fluoride (BeF(x)) among the phosphate analogs studied inhibits Bacillus cereus sphingomyelinase (SMase) activity. The active inhibitory species proved to be not BeF(3)(-) but BeF(2) by the measurement of SMase activity and of (19)F NMR spectroscopy in the presence of a fixed concentration of BeCl(2) and different concentrations of NaF, although both the species have been reported for other kinds of enzymes. The result of kinetic experiment also indicated that the BeF(x) binds in the vicinity of the essential binding site for the substrate and that the Mg(2+) binding to SMase is essential for the binding of BeF(x) to the enzyme.     

Recruitment of the amphidromous goby <Emphasis Type="Italic">Sicyopterus japonicus</Emphasis> to the estuary of the Ota River,Wakayama, Japan

Ecological aspects of recruitment in the amphidromous goby, Sicyopterus japonicus, were studied from larval collections made with a set net in the estuary of the Ota River, Wakayama, Japan. The abundance patterns of the 12,766 larvae collected from 18 April to 26 August 2006 showed several peaks during the recruitment season. Their body sizes at recruitment ranged from 23.5 to 30.0 mm standard length (mean ± SD, 26.3 ± 1.1 mm), 0.11 to 0.49 g body weight (0.22 ± 0.05 g), and 8 to 20 condition factor (11 ± 2). The standard length of the goby larvae tended to decrease with the season, while their body weight slightly increased and resulted in an increase in condition factor. The recruitment of larvae occurred mainly during the daytime. Otolith growth increment analysis of 30 larvae collected by a square lift net on 30 April 2005 revealed that the oceanic larval duration after downstream migration ranged from 173 to 253 days (208 ± 22) after hatching. A limited time of recruitment in early summer and a considerably long duration of oceanic life (about a half year) appeared to be unique characteristics of this Sicyopterus species that lives in a temperate region in comparison to other tropical species of the genus Sicyopterus that all have year-round recruitment.     

Formation of Nicotinamide Ribose Diphosphate Ribose,a New Metabolite of NAD,by Aspergillus niger

Aspergillus niger (AKU 3302) degraded NAD to form Compound X. This compound was identified as nicotinamide ribose diphosphate ribose (NAmRDPR) by hydrolysis with alkaline or phosphodiesterase followed by chemical analysis of the products. NAmRDPR showed absorption maxima at 265~266 nm in 0.1 n HCI and 325 nm in 1.0 n KCN. Optimal pH for NAmRDPR formation by the enzyme preparation from this organism was around 4.0. Formation of NAmRDPR proceeded stoichiometrically with degradation of NAD. Some of other strains of A. niger formed NAmRDPR, but production of this compound was not demonstrated in other mold genera.     

Expression and distribution of fugu TIMP-2s (fgTIMP-2a and fgTIMP-2b) mRNAs in tissues and embryos

In teleosts, two distinct types of TIMP-2s occur, TIMP-2a and TIMP-2b, but little is known about their locations and quantitative expressions. Here, we examined pufferfish (Takifugu rubripes) TIMP-2a (fgTIMP-2a) and TIMP-2b (fgTIMP-2b) quantities and locations in fugu adult tissues and embryos. To compare the quantitative expression of fgTIMP-2s, we performed a quantitative real-time PCR (qPCR). FgTIMP-2a mRNA was constitutively expressed and significant differences in expression were not observed among adult tissues. Whereas, fgTIMP-2b mRNA was significantly differently expressed in ordinary muscle and gill compared to the expression level in whole blood (P<0.05). Although significant difference was not observed between brain and other tissues, both fgTIMP-2s mRNAs were abundant in the brain. In addition, we examined embryos during development using qPCR. Both fgTIMP-2s mRNAs gradually increased during embryonic development from 48 hpf. However, fgTIMP-2b mRNA was obviously abundant compared to fgTIMP-2a mRNA in embryos. We also examined the specific mRNA distribution in embryos. The fgTIMP-2s mRNAs showed the same distribution during development. Both fgTIMP-2s are expressed in adult fugu tissues and embryos but their expression levels clearly differ, suggesting that there is a predominance of fgTIMP-2b over fgTIMP-2a in vivo.     

Expression of carboxylesterase and lipase genes in rat liver cell-types

Approximately 80% of the body vitamin A is stored in liver stellate cells with in the lipid droplets as retinyl esters. In low vitamin A status or after liver injury, stellate cells are depleted of the stored retinyl esters by their hydrolysis to retinol. However, the identity of retinyl ester hydrolase(s) expressed in stellate cells is unknown. The expression of carboxylesterase and lipase genes in purified liver cell-types was investigated by real-time PCR. We found that six carboxylesterase and hepatic lipase genes were expressed in hepatocytes. Adipose triglyceride lipase was expressed in Kupffer cells, stellate cells and endothelial cells. Lipoprotein lipase expression was detected in Kupffer cells and stellate cells. As a function of stellate cell activation, expression of adipose triglyceride lipase decreased by twofold and lipoprotein lipase increased by 32-fold suggesting that it may play a role in retinol ester hydrolysis during stellate cell activation.     

Unprecedented intraspecific diversity of the MHC class I region of a teleost medaka, Oryzias latipes

The major histocompatibility complex (MHC) is present at a single chromosomal locus of all jawed vertebrate analyzed so far, from sharks to mammals, except for teleosts whose orthologs of the mammalian MHC-encoded genes are dispersed at several chromosomal loci. Even in teleosts, several class IA genes and those genes directly involved in class I antigen presentation preserve their linkage, defining the teleost MHC class I region. We determined the complete nucleotide sequence of the MHC class I region of the inbred HNI strain of medaka, Oryzias latipes (northern Japan population-derived), from four overlapping bacterial artificial chromosome (BAC) clones spanning 540,982 bp, and compared it with the published sequence of the corresponding region of the inbred Hd-rR strain of medaka (425,935 bp, southern Japan population-derived) as the first extensive study of intraspecies polymorphisms of the ectotherm MHC regions. A segment of about 100 kb in the middle of the compared sequences encompassing two class Ia genes and two immunoproteasome subunit genes, PSMB8 and PSMB10, was so divergent between these two inbred strains that a reliable sequence alignment could not be made. The rest of the compared region (about 320 kb) showed a fair correspondence, and an approximately 96% nucleotide identity was observed upon gap-free segmental alignment. These results indicate that the medaka MHC class I region contains an ∼100-kb polymorphic core, which is most probably evolving adaptively by accumulation of point mutations and extensive genetic rearrangements such as insertions, deletions and duplications. The nucleotide sequence data of HNI MHC class I region reported in this paper have been submitted to the DDBJ/EMBL/GenBank and were assigned the accession number AB183488.     

Involvement of c-Jun N-terminal kinase in amyloid precursor protein-mediated neuronal cell death

Amyloid precursor protein (APP), the precursor of Abeta, has been shown to function as a cell surface receptor that mediates neuronal cell death by anti-APP antibody. The c-Jun N-terminal kinase (JNK) can mediate various neurotoxic signals, including Abeta neurotoxicity. However, the relationship of APP-mediated neurotoxicity to JNK is not clear, partly because APP cytotoxicity is Abeta independent. Here we examined whether JNK is involved in APP-mediated neuronal cell death and found that: (i) neuronal cell death by antibody-bound APP was inhibited by dominant-negative JNK, JIP-1b and SP600125, the specific inhibitor of JNK, but not by SB203580 or PD98059; (ii) constitutively active (ca) JNK caused neuronal cell death and (iii) the pharmacological profile of caJNK-mediated cell death closely coincided with that of APP-mediated cell death. Pertussis toxin (PTX) suppressed APP-mediated cell death but not caJNK-induced cell death, which was suppressed by Humanin, a newly identified neuroprotective factor which inhibits APP-mediated cytotoxicity. In the presence of PTX, the PTX-resistant mutant of Galphao, but not that of Galphai, recovered the cytotoxic action of APP. These findings demonstrate that JNK is involved in APP-mediated neuronal cell death as a downstream signal transducer of Go.