Partial Sequences of Large Subunit Ribosomal DNA of a New Yeast Species,Trichosporon domesticum and Related Species

We determined the partial sequences of large subunit rDNA of a new yeast species, Trichosporon domesticum, which was isolated from the house of a summer-type hypersensitivity pneumonitis patient. Phylogenetically, T. domesticum was positioned in the taxonomic group containing T. montevideense and T. brassicae, which indicated an identical serotype. A phylogenetic relationship among all species of the genus Trichosporon which belong to the basidiomycetous yeast is clarified.     

Comparative studies on the properties of spinach chloroplasts prepared by media containing choline chloride or sucrose

Spinach chloroplasts were isolated and stored in a medium containing0.5 M choline chloride. The properties of these chloroplastswere compared with those of chloroplasts prepared in an ordinarysucrose medium. In marked contrast to sucrose-prepared chloroplasts, choline-preparedchloroplasts did not show "conventional uncoupling" (stimulationof ferricyanide reduction paralleling the inactivation of phosphorylation)after transient warming in the temperature range between 20?and 55?C. The thermal stability of the oxygen evolving system, the vulnerabilityof the lipophilic structure in the thylakoids to alcohol duringthe warming treatment, and the effects of amine on photophosphorylationwere similar in both chloroplast preparations. After the warming treatment, the degree of swelling in chloroplastswas larger and the intermediate electron transport systme (fromreduced 2,6-dichlorophenolindophenol to methyl viologen) wasmore stable against uncoupling, in choline-prepared chloroplaststhan in sucrose-prepared ones. The presence and absence of "conventional uncoupling" in twochloroplast preparations were ascribed to differences in thermalstability. In choline-prepared chloroplasts the uncoupling temperatureof the electron transport system was higher than the inactivationtemperature of the oxygen evolving system, but it was lowerin the sucrose-prepared ones. (Received February 13, 1974; )     

Lipophilic interaction between thylakoid membranes and aliphatic compounds

Spinach chloroplasts pre-incubated at various temperatures, changed their photosynthetic activities (measured at 15°C) as the incubation temperature was raised; these activities showed characteristic activitytemperature profiles as follows:

1. The profiles were shifted to lower temperatures if various aliphatic compounds were present in the incubation mixture.
2. In general, the extent of the shift was proportional to the product of the concentration and the partition coefficient of the compound, i.e. to the concentration of the compound partitioned in the lipophilic chloroplast phase.

The combined effects of heat and the aliphatic compounds tested indicated that the lipophilic groups in these compounds play a determinative role in the heat denaturation of thylakoids. The consequence of such structure alterations is inactivation of photosynthetic functions. The lipophilic properties of the spinach thylakoid membrane as compared with certain artificial and natural membranes are described.     

Knockdown of Carotenoid Cleavage Dioxygenase 4 (CCD4) via Virus-Induced Gene Silencing Confers Yellow Coloration in Peach Fruit: Evaluation of Gene Function Related to Fruit Traits

Plant Molecular Biology Reporter - Transgenic approach is an excellent way for the clarification of gene function, but it is generally difficult to create transgenic plants for most of the fruit...     

Water-soluble fractions from defatted sesame seeds protect human neuroblast cells against peroxyl radicals and hydrogen peroxide-induced oxidative stress

Oxidative stress is involved in the development of aging-related diseases, such as neurodegenerative diseases. Dietary antioxidants that can protect neuronal cells from oxidative damage play an important role in preventing such diseases. Previously, we reported that water-soluble fractions purified from defatted sesame seed flour exhibit good antioxidant activity in vitro. In the present study, we investigated the protective effects of white and gold sesame seed water-soluble fractions (WS-wsf and GS-wsf, respectively) against 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH) and hydrogen peroxide (H₂O₂) induced oxidative stress in human neuroblast SH-SY5Y cells. Pretreatment with WS-wsf and GS-wsf did not protect cells against AAPH-induced cytotoxicity, while simultaneous co-treatment with AAPH significantly improved cell viability and inhibited membrane lipid peroxidation. These results suggest that WS-wsf and GS-wsf protect cells from AAPH-induced extracellular oxidative damage via direct scavenging of peroxyl radicals. When oxidative stress was induced by H₂O₂, pretreatment WS-wsf and GS-wsf significantly enhanced cell viability. These results suggest that in addition to radical scavenging, WS-wsf and GS-wsf enhance cellular resistance to intracellular oxidative stress by activation of the Nrf-2/ARE pathway as confirmed by the increased Nrf2 protein level in the nucleus and increased heme oxygenase 1 (HO-1) mRNA expression. The roles of ferulic and vanillic acids as bioactive antioxidants in these fractions were also confirmed. In conclusion, our results indicated that WS-wsf and GS-wsf, which showed antioxidant activity in vitro, are also efficient antioxidants in a cell system protecting SH-SY5Y cells against both extracellular and intracellular oxidative stress.     

A Novel Nectin-mediated Cell Adhesion Apparatus That Is Implicated in Prolactin Receptor Signaling for Mammary Gland Development

Mammary gland development is induced by the actions of various hormones to form a structure consisting of collecting ducts and milk-secreting alveoli, which comprise two types of epithelial cells known as luminal and basal cells. These cells adhere to each other by cell adhesion apparatuses whose roles in hormone-dependent mammary gland development remain largely unknown. Here we identified a novel cell adhesion apparatus at the boundary between the luminal and basal cells in addition to desmosomes. This apparatus was formed by the trans-interaction between the cell adhesion molecules nectin-4 and nectin-1, which were expressed in the luminal and basal cells, respectively. Nectin-4 of this apparatus further cis-interacted with the prolactin receptor in the luminal cells to enhance the prolactin-induced prolactin receptor signaling for alveolar development with lactogenic differentiation. Thus, a novel nectin-mediated cell adhesion apparatus regulates the prolactin receptor signaling for mammary gland development.     

Immunization of A4galt-deficient mice with glycosphingolipids from renal cell cancers resulted in the generation of anti-sulfoglycolipid monoclonal antibodies

In this study, we immunized Gb3/CD77 synthase gene (A4galt) knockout (KO) mice with glycosphingolipids (GSLs) extracted from 3 renal cell cancer (RCC) cell lines to raise monoclonal antibodies (mAbs) reactive with globo-series GSLs specifically expressed in RCCs. Although a number of mAbs reactive with globo-series GSLs were generated, they reacted with both RCC cell lines and normal kidney cells. When we analyzed recognized antigens by mAbs that were specifically reactive with RCC, but not with normal kidney cells at least on the cell surface, many of them turned out to be reactive with sulfoglycolipids. Eight out of 11 RCC-specific mAbs were reactive with SM2 alone, and the other 3 mAbs were more broadly reactive with sulfated glycolipids, i.e. SM3 and SM4 as well as SM2. In the immunohistochemistry, these anti-sulfoglycolipids mAbs showed RCC-specific reaction, with no or minimal reaction with adjacent normal tissues. Thus, immunization of A4galt KO mice with RCC-derived GSLs resulted in the generation of anti sulfated GSL mAbs, and these mAbs may be applicable for the therapeutics for RCC patients.     

Phosphorus and nitrogen resorption from different chemical fractions in senescing leaves of tropical tree species on Mount Kinabalu,Borneo

Nutrient resorption, a process by which plants degrade organic compounds and resorb their nutrients from senescing tissues, is a crucial plant function to increase growth and fitness in nutrient-poor environments. Tropical trees on phosphorus (P)-poor soils are particularly known to have high P-resorption efficiency (PRE, the percentage of P resorbed from senescing leaves before abscission per total P in green leaves). However, the biochemical mechanisms underlying this greater PRE remain unclear. In this study, we determined the P concentration in easily soluble, nucleic acid, lipid and residual fractions for green and senescent leaves of 22 tree species from three sites, which differed in P availability, on the lower flanks of Mt. Kinabalu, Borneo. PRE varied from 24 to 93% and was higher in species from the P-poor site. P-resorption rate was greatest from the lipid fraction, the nucleic acid fraction, and lowest in the easily soluble fraction and the residual fraction when all the species were pooled. For species with higher PRE, P-resorption rate of the residual fraction was relatively high and was comparable in magnitude to that of the other labile fractions. This suggests that tree species inhabiting P-poor environments increased PRE by improving the degradation of recalcitrant compounds. This study suggests that plants selectively degrade organic compounds depending on environmental conditions, which is a key mechanism underlying the variation of PRE.