Suppression of the rice heterotrimeric G protein β-subunit gene, RGB1, causes dwarfism and browning of internodes and lamina joint regions

In the present study, we investigated the function of the heterotrimeric G protein β-subunit (Gβ) gene (RGB1) in rice. RGB1 knock-down lines were generated in the wild type and d1-5, a mutant deficient for the heterotrimeric G protein α-subunit (Gα) gene (RGA1). Both transgenic lines showed browning of the lamina joint regions and nodes that could be attributed to a reduction of RGB1 function, as the abnormality was not observed in d1-5. The RGB1 knock-down lines generated in d1-5 were shorter, suggesting RGB1 to be a positive regulator of cellular proliferation, in addition to RGA1. The number of sterile seeds also increased in both RGB1 knock-down lines. These results suggest that Gβγ and Gα cooperatively function in cellular proliferation and seed fertility. We discuss the potential predominant role of RGB1 in G protein signaling in rice.     

Evaluation of the larval distribution and migration of the Japanese eel in the western North Pacific

The distribution of all larval stages of the Japanese eel, Anguilla japonica, were examined using historical catch records and original data in the western North Pacific (WNP) to evaluate existing information about the larval distribution and migration of this species. A total of 148 preleptocephali, 2547 leptocephali, 6 metamorphosing larvae, and 21 glass eels were collected during 37 cruises over a 52-year period (1956?C2007). Sampling effort was spatio-temporally biased in latitude/longitude among seasons with sampling effort being concentrated near the western margin of the subtropical gyre near Taiwan in the winter season and extensive effort occurring near the spawning area to the east near the seamount chain of the West Mariana Ridge in summer during the spawning season. The distribution of preleptocephali (4.2?C8.7 mm) was limited to a narrow area around 14°N, 142°E just west of the southern part of the seamount chain, while leptocephali (7.7?C62.0 mm) were widely distributed at increasing size westward in the North Equatorial Current (NEC) to the region east of Taiwan. Metamorphosing larvae (52.7?C61.2 mm) were collected only in the area 21?C26°N, 121?C129°E to the east of Taiwan, while glass eels (51.3?C61.2 mm) occurred only within or west of the Kuroshio. These distributions suggest that leptocephali begin to metamorphose within or just east of the Kuroshio, then after completion of metamorphosis the glass eels detrain from the current and migrate inshore. The relationship between catch date and body size of leptocephali suggested that the spawning season is from April to August, but further sampling is needed to eliminate possible effects of sampling bias. This analysis is consistent with the existing hypothesis that Japanese eel larvae born near the West Mariana Ridge are transported westward in the NEC and then transfer to the Kuroshio to recruit to East Asia, although more sampling effort is needed for later stage larvae in the NEC bifurcation region to help understand the larval migration in relation to the possible impacts of ocean?Catmosphere changes.     

Effect of an excess intake of casein hydrolysate containing Val-Pro-Pro and Ile-Pro-Pro in subjects with normal blood pressure, high-normal blood pressure, or mild hypertension

A double-blind, placebo-controlled, randomized clinical trial was conducted to evaluate the effects of ingesting an excess of tablets containing casein hydrolysate, incorporating angiotensin I-converting enzyme (ACE) inhibitory peptides such as Val-Pro-Pro (VPP) and Ile-Pro-Pro (IPP), in subjects with blood pressure ranging from normal to mild hypertension. A total of 48 subjects were given either 5 times more than the effective amount of casein hydrolysate or a placebo in tablet form for 4 weeks. In the active group, systolic blood pressure (SBP) decreased significantly as compared with the placebo group. In stratified analysis, however, this antihypertensive effect was not found in normotensive subjects. In addition, neither an acute or nor an excessive reduction in blood pressure nor clinically important adverse events were observed in this study. These findings suggest that intake of a 5-fold excess of tablets containing casein hydrolysate can lead to a mild improvement in hypertension without side effects.     

Neokomagataea gen. nov., with descriptions of Neokomagataea thailandica sp. nov. and Neokomagataea tanensis sp. nov., osmotolerant acetic acid bacteria of the α-Proteobacteria

Isolates AH11(T) and AH13(T) were isolated from flowers of lantana and candle bush respectively collected in Thailand. In phylogenetic trees based on 16S rRNA gene sequences, the two isolates formed an independent cluster, which was then connected to the type strain of Saccharibacter floricola. The calculated pair-wise 16S rRNA gene sequence similarities of isolate AH11(T) were 95.7-92.3% to the type strains of the type species of the 12 genera of acetic acid bacteria. The DNA base composition was from 51.2 to 56.8 mol % G+C, with a range of 5.6 mol %. When isolate AH11(T) was labeled, DNA-DNA similarities were 100, 12, 4, 5, and 4% respectively to isolates AH11(T) and AH13(T) and the type strains of Saccharibacter floricola, Gluconobacter oxydans, and Acetobacter aceti. The two isolates were non-motile and did not oxidize either acetate or lactate. No growth was found in the presence of 0.35% acetic acid w/v. The two isolates were not osmophilic but osmotolerant, produced 2,5-diketo-D-gluconate from D-glucose, and did not oxidize lactate, thus differing from strains of Saccharibacter floricola, which showed weak lactate oxidation. The two isolates contained unsaturated C(18:1)ω7c fatty acid as the major fatty acid, and were unique in the presence of a considerable amount of straight-chain C(18:1)2OH fatty acid. Q-10 was present as the major isoprenoid quinone. Neokomagataea gen. nov. was proposed with the two species, Neokomagataea thailandica sp. nov. for isolate AH11(T) (=BCC 25710(T)=NBRC 106555(T)), which has 56.8 mol % G+C, and Neokomagataea tanensis sp. nov. for isolate AH13(T) (=BCC 25711(T)=NBRC 106556(T)), which has 51.2 mol % G+C.     

Persimmon leaf extract inhibits the ATM activity during DNA damage response induced by Doxorubicin in A549 lung adenocarcinoma cells

Persimmon leaf (PL) has been commonly recognized for its wide variety of health benefits. A previous study has reported that persimmon leaf extract (PLE) contained flavonols with the 2″-galloly moiety (PLEg). Galloylated homologues generically show stronger activity in their biological function, so enhanced functions can be expected for PLEg. We investigated in this present study the effect of PLEg on the cellular DNA damage checkpoint signaling to sensitize cancer chemotherapy. Treatment with PLE and PLEg significantly increased the cytotoxicity of doxorubicin (DOX) in A549 adenocarcinoma cells. PLE and PLEg reduced the phosphorylation of checkpoint proteins such as structural maintenance of chromosomes 1 (SMC1), checkpoint kinase 1 (Chk1), and p53 in DOX-treated cells. Moreover, PLE decreased the phosphorylation of ATM (ataxia telangiectasia mutated) in a dose-dependent manner. PLE, and especially PLEg, abrogated the G2/M checkpoint during DOX-induced DNA damage. These results suggest that PLEg specifically inhibited ATM-dependent checkpoint activation by DOX, and that PLEg might be a useful sensitizer in cancer chemotherapy.     

Double-knockout of putative endo-β-N-acetylglucosaminidase (ENGase) genes in Arabidopsis thaliana: loss of ENGase activity induced accumulation of high-mannose type free N-glycans bearing N,N'-acetylchitobiosyl unit

Endo-β-N-acetylglucosaminidase (ENGase) is involved in the production of high-mannose type free N-glycans during plant development and fruit maturation. In a previous study (K. Nakamura et al. Biosci. Biotechnol. Biochem., 73, 461-464 (2009)), we identified the tomato ENGase gene and found that gene expression remained relatively constant. In the present study, we constructed an Arabidopsis thaliana mutant in which the expression of two putative ENGase genes was suppressed. The mutant showed no ENGase activity, but produced high-mannose type free N-glycans carrying the N,N'-acetylchitobiosyl unit that is produced by peptide:N-glycanase, indicating that both these genes encode Arabidopsis ENGase.     

Calpain-7 binds to CHMP1B at its second α-helical region and forms a ternary complex with IST1

Some intracellular proteins involved in the endosomal sorting complex required for transport (ESCRT) system have microtubule interacting and transport (MIT) domains and bind to ESCRT-III protein family members named charged multivesicular body proteins (CHMPs) at their C-terminal regions containing MIT-interacting motifs (MIMs). While two types of MIMs (MIM1 and MIM2) have been reported, CHMP1B has MIM1 and IST1 has both MIM1 and MIM2. Previously, we demonstrated that CHMP1B and IST1 directly interacted with a tandem repeat of MIT domains of calpain-7 (CL7MIT) and that autolytic activity of calpain-7 was enhanced by IST1 in vitro but not by overexpression of IST1 in HEK293T cells. In this study, we detected enhancement of autolysis of mGFP-fused calpain-7 by coexpression with CHMP1B and observed further activation by additional coexpression of IST1 in HEK293T cells. We found that CL7MIT interacted with the second α-helical region of CHMP1B but not with the canonical C-terminal region containing MIM1 in vitro. Co-immunoprecipitation assays demonstrated that the interaction between CL7MIT and CHMP1B and between CL7MIT and IST1 became stronger when IST1 or CHMP1B was additionally coexpressed, suggesting formation of ternary complex of calpain-7, IST1 and CHMP1B. Moreover, subcellular fractionation analyses revealed increase of calpain-7 in membrane/organelle fractions by concomitant overexpression of these ESCRT-III family member proteins.     

Molecular cloning and characterization of a beta-L-Arabinobiosidase in Bifidobacterium longum that belongs to a novel glycoside hydrolase family

Extensin is a glycoprotein that is rich in hydroxyprolines linked to β-L-arabinofuranosides. In this study, we cloned a hypBA2 gene that encodes a novel β-L-arabinobiosidase from Bifidobacterium longum JCM 1217. This enzyme does not have any sequence similarity with other glycoside hydrolase families but has 38-98% identity to hypothetical proteins in Bifidobacterium and Xanthomonas strains. The recombinant enzyme liberated L-arabinofuranose (Araf)-β1,2-Araf disaccharide from carrot extensin, potato lectin, and Araf-β1,2-Araf-β1,2-Araf-β-Hyp (Ara(3)-Hyp) but not Araf-α1,3-Araf-β1,2-Araf-β1,2-Araf-β-Hyp (Ara(4)-Hyp) or Araf-β1,2-Araf-β-Hyp (Ara(2)-Hyp), which indicated that it was specific for unmodified Ara(3)-Hyp substrate. The enzyme also transglycosylated 1-alkanols with retention of the anomeric configuration. This is the first report of an enzyme that hydrolyzes Hyp-linked β-L-arabinofuranosides, which defines a new family of glycoside hydrolases, glycoside hydrolase family 121.     

Paired immunoglobulin-like receptor B knockout does not enhance axonal regeneration or locomotor recovery after spinal cord injury

Myelin components that inhibit axonal regeneration are believed to contribute significantly to the lack of axonal regeneration noted in the adult central nervous system. Three proteins found in myelin, Nogo, myelin-associated glycoprotein, and oligodendrocyte-myelin glycoprotein, inhibit neurite outgrowth in vitro. All of these proteins interact with the same receptors, namely, the Nogo receptor (NgR) and paired immunoglobulin-like receptor B (PIR-B). As per previous reports, corticospinal tract (CST) regeneration is not enhanced in NgR-knock-out mice after spinal cord injury. Therefore, we assessed CST regeneration in PIR-B-knock-out mice. We found that hindlimb motor function, as assessed using the Basso mouse scale, footprint test, inclined plane test, and beam walking test, did not differ between the PIR-B-knock-out and wild-type mice after dorsal hemisection of the spinal cord. Further, tracing of the CST fibers after injury did not reveal enhanced axonal regeneration or sprouting in the CST of the PIR-B-knock-out mice. Systemic administration of NEP1-40, a NgR antagonist, to PIR-B knock-out mice did not enhance the regenerative response. These results indicate that PIR-B knock-out is not sufficient to induce extensive axonal regeneration after spinal cord injury.     

Functional activation of Src family kinase yes protein is essential for the enhanced malignant properties of human melanoma cells expressing ganglioside GD3

The possible roles of Src family kinases in the enhanced malignant properties of melanomas related to GD3 expression were analyzed. Among Src family kinases only Yes, not Fyn or Src, was functionally involved in the increased cell proliferation and invasion of GD3-expressing transfectant cells (GD3+). Yes was located upstream of p130Cas and paxillin and at an equivalent level to focal adhesion kinase. Yes underwent autophosphorylation even before serum treatment and showed stronger kinase activity in GD3+ cells than in GD3- cells following serum treatment. Coimmunoprecipitation experiments revealed that Yes bound to focal adhesion kinase or p130Cas more strongly in GD3+ cells than in GD3- cells. As a possible mechanism for the enhancing effects of GD3 on cellular phenotypes, it was shown that majority of Yes was localized in glycolipid-enriched microdomain/rafts in GD3+ cells even before serum treatment, whereas it was scarcely detected in glycolipid-enriched microdomain/rafts in GD3- cells. An in vitro kinase assay of Yes revealed that coexistence of GD3 with Yes in membranous environments enhances the kinase activity of GD3- cell-derived Yes toward enolase, p125, and Yes itself. Knockdown of GD3 synthase resulted in the alleviation of tumor phenotypes and reduced activation levels of Yes. Taken together, these results suggest a role of GD3 in the regulation of Src family kinases.