Molecular mechanism underlying pseudopeloria in Habenaria radiata (Orchidaceae)

Habenaria radiata (Orchidaceae) has two whorls of perianth, comprising three greenish sepals, two white petals and one lip (labellum). By contrast, the pseudopeloric (with a decreased degree of zygomorphy) mutant cultivar of H. radiata , ‘Hishou’, has changes in the identities of the dorsal sepal to a petaloid organ and the two ventral sepals to lip‐like organs. Here, we isolated four DEFICIENS ‐ like and two AGL 6 ‐like genes from H. radiata , and characterized their expression. Most of these genes revealed similar expression patterns in the wild type and in the ‘Hishou’ cultivar, except Hr DEF ‐C3. The Hr DEF ‐C3 gene was expressed in petals and lip in the wild type but was ectopically expressed in sepal, petals, lip, leaf, root and bulb in ‘Hishou’. Sequence analysis of the Hr DEF ‐C3 loci revealed that the ‘Hishou’ genome harbored two types of Hr DEF ‐C3 genes: one identical to wild‐type Hr DEF ‐C3 and the other carrying a retrotransposon insertion in its promoter. Genetic linkage analysis of the progeny derived from an intraspecific cross between ‘Hishou’ and the wild type demonstrated that the mutant pseudopeloric trait was dominantly inherited and was linked to the Hr DEF ‐C3 gene carrying the retrotransposon. These results indicate that the pseudopeloric phenotype is caused by retrotransposon insertion in the Hr DEF ‐C3 promoter, resulting in the ectopic expression of Hr DEF ‐C3 . As the expression of Hr AGL 6‐C2 was limited to lateral sepals and lip, the overlapping expression of Hr DEF ‐C3 and Hr AGL 6‐C2 is likely to be responsible for the sepal to lip‐like identity in the lateral sepals of the ‘Hishou’ cultivar.     

Comparative study of four arginine ester hydrolases, ME-1, 2, 3 and 4 from the venom of Trimeresurus mucrosquamatus (the Chinese habu snake)

Four arginine ester hydrolases, ME-1, 2, 3 and 4 from the venom of Trimeresurus mucrosquamatus had been isolated and characterized by Sugihara et al. (1980, 1981, 1982, 1983). Immunologically, ME-1, 2, 3 and 4 are identical. The four enzymes hydrolyzed Pro-Phe-Arg-MCA and z-Phe-Arg-MCA. Furthermore, ME-2 slightly hydrolyzed Boc-Val-Pro-Arg-MCA, Boc-Phe-Ser-Arg-MCA and Boc-Ile-Glu-Gly-Arg-MCA. ME-1 cleaved almost simultaneously the Arg(22)-Gly(23) and Phe(25)-Tyr(26) bond of oxidized insulin B chain. ME-2 and 3 also hydrolyzed the same bond of insulin B chain, but the activity was not as potent as ME-1. ME-4 did not cleave the substrate. The four enzymes hydrolyzed C-terminal of arginine in the biologically active peptides. Four arginine ester hydrolases showed fibrinogenolytic activity. ME-1 and 2 first cleaved B beta-chain and then A alpha-chain. On the contrary, ME-3 and 4 cleaved A alpha- and B beta-chain simultaneously. The four enzymes also hydrolyzed fibrinogen in plasma cleaving B beta- and gamma-chain and slightly digesting A alpha-chain. The various inhibitors affected TAME (tosyl-arginine-methylester) and the fibrinogen hydrolytic activity of the four enzymes. All four enzymes had fibrinolytic activity.     

Formation of lactic acid from glycolaldehyde by alkaline hydrothermal reaction

Alkali hydrothermal experiments with glycolaldehyde were carried out at 300 degrees C. Glycolaldehyde was converted into lactic acid in a yield of 28% based on the starting carbon mass of glycolaldehyde. A conversion pathway for glycolaldehyde into lactic acid is proposed and our results suggest that the pathway via glycolaldehyde is also important in the conversion of glucose into lactic acid.     

Dietary daidzein,but not genistein,has a hypocholesterolemic effect in non-ovariectomized and ovariectomized female Sprague-Dawley rats on a cholesterol-free diet

We compared the effects of two major isoflavones, daidzein and genistein, on lipid metabolism in rats. Daidzein (150 mg/kg diet), genistein (150 mg/kg diet), daidzein and genistein (1:1, 300 mg/kg diet), or control diets were fed to 4 groups of 6-week-old ovariectomized (Ovx) and non-Ovx Sprague Dawley rats for 4 weeks. Dietary daidzein, but not genistein, reduced serum and hepatic total cholesterol levels significantly relative to that by the control group, regardless of whether the rats had undergone ovariectomy. Genistein did not exhibit any physiological effects on lipid levels, but did affect genes involved in cholesterol metabolism. These results indicate that daidzein and genistein may influence lipid regulation via differing modes of action.     

A Conserved Function in Phosphatidylinositol Metabolism for Mammalian Vps13 Family Proteins

The Vps13 protein family is highly conserved in eukaryotic cells. In humans, mutations in the gene encoding the family member VPS13A lead to the neurodegenerative disorder chorea-acanthocytosis. In the yeast Saccharomyces cerevisiae, there is just a single version of VPS13, thereby simplifying the task of unraveling its molecular function(s). While VPS13 was originally identified in yeast by its role in vacuolar sorting, recent studies have revealed a completely different function for VPS13 in sporulation, where VPS13 regulates phosphatidylinositol-4-phosphate (PtdIns(4)P) levels in the prospore membrane. This discovery raises the possibility that the disease phenotype associated with vps13A mutants in humans is due to misregulation of PtdIns(4)P in membranes. To determine whether VPS13A affects PtdIns(4)P in membranes from mammalian neuronal cells, phosphatidylinositol phosphate pools were compared in PC12 tissue culture cells in the absence or presence of VPS13A. Consistent with the yeast results, the localization of PtdIns(4)P is specifically altered in VPS13A knockdown cells while other phosphatidylinositol phosphates appear unaffected. In addition, VPS13A is necessary to prevent the premature degeneration of neurites that develop in response to Nerve Growth Factor. The regulation of PtdIns(4)P is therefore a conserved function of the Vps13 family and may play a role in the maintenance of neuronal processes in mammals.     

Organization of the teleostean nucleus rotundus.

The nucleus rotundus of 21 species of teleosts was studied by a modified Bodian and the Golgi method to clarify the histological organization, with special reference to the cell lamination and the glomerular formation. The common components of the nucleus in all species are as follows: a thick fiber bundle which comes from the commissura horizontalis and enters the nucleus from the dorsal surface, many small cells, large cells, glomeruli, and a surrounding fibrous capsule. The nuclei of all species studied are classified into three types mainly on the distribution of the small cells, and to a lesser degree on the location of the large cells and the glomeruli. The first type of nucleus has small cells, large cells and glomeruli throughout its extent. In the second type of nucleus, many small cells form a peripheral cell layer, while the large cells and glomeruli are found all over the nucleus. The third type of nucleus is clearly laminated. It is composed of four layers arranged concentrically around a central fiber net in the following order: a glomerular layer, a fibrous layer, a small-cell layer, and a peripheral fibrous capsule. In some species, the large cells are located in the fibrous capsule, and all glomeruli contain a star-like structure, which corresponds to the tips of the large cell dendrites.