Calcium-mediated association of a putative vacuolar sorting receptor PV72 with a propeptide of 2S albumin.

PV72, a type I membrane protein with three epidermal-growth factor (EGF)-like motifs, was found to be localized on the membranes of the precursor-accumulating (PAC) vesicles that accumulated precursors of various seed storage proteins. To clarify the function of PV72 as a sorting receptor, we expressed four modified PV72s and analyzed their ability to bind the internal propeptide (the 2S-I peptide) of pro2S albumin by affinity chromatography and surface plasmon resonance. The recombinant PV72 specifically bound to the 2S-I peptide with a K(D) value of 0.2 microm, which was low enough for it to function as a receptor. The EGF-like motifs modulated the Ca(2+)-dependent conformational change of PV72 to form a functional pocket for the ligand binding. The binding of Ca(2+) stabilizes the receptor-ligand complex even at pH 4.0. The association and dissociation of PV72 with the ligand is modulated by the Ca(2+) concentration (EC(50) value = 40 microm) rather than the environmental pH. Overall results suggest that Ca(2+) regulates the vacuolar sorting mechanism in higher plants.     

Application of microcolumn ion chromatography using anion exchangers modified with dextran sulfate for the determination of alkali and alkaline-earth metal ions

Microcolumn ion chromatography using anion exchangers modified with dextran sulfate has been applied to the determination of alkali and alkaline-earth metal ions contained in guinea pig serum and bovine serum. These serums contained Na⁺, NH₄⁺, K⁺, Mg²⁺ and Ca²⁺ and they were indirectly detected at 200 nm. The determination was done without any pretreatment procedure other than dilution.     

Mammalian septins nomenclature

There are 10 known mammalian septin genes, some of which produce multiple splice variants. The current nomenclature for the genes and gene products is very confusing, with several different names having been given to the same gene product and distinct names given to splice variants of the same gene. Moreover, some names are based on those of yeast or Drosophila septins that are not the closest homologues. Therefore, we suggest that the mammalian septin field adopt a common nomenclature system, based on that adopted by the Mouse Genomic Nomenclature Committee and accepted by the Human Genome Organization Gene Nomenclature Committee. The human and mouse septin genes will be named SEPT1-SEPT10 and Sept1-Sept10, respectively. Splice variants will be designated by an underscore followed by a lowercase "v" and a number, e.g., SEPT4_v1.     

Immunophenotypical analyses of myofibroblasts in rat excisional wound healing: possible transdifferentiation of blood vessel pericytes and perifollicular dermal sheath cells into myofibroblasts

Cutaneous fibrosis after wound is evoked by myofibroblasts capable of producing collagen; the derivation and features remain to be investigated. Immunophenotypical characteristics of myofibroblasts were analysed in excisional rat wound healing, of which samples were obtained on post-wounding (PW) days 1 to 26. Myofibroblasts were characterized for expressions of intermediate cytoskeletons such as vimentin, desmin, and α-smooth muscle actin (α-SMA). To pursue the progenitor, immunolabeling analyses were performed using stromal-/bone marrow-stem cell markers (Thy-1 and A3). Myofibroblasts reacting to vimentin and α-SMA were first seen on PW day 5, then peaked on PW day 9 in granulation tissues, and gradually decreased in remodeling tissues; these immunopositive cells reacted simultaneously to Thy-1. Desmin-reacting cells were limited to newly-formed blood vessels in wound bed. The single/double immunolabelings revealed that pericytes (identified by positive reaction to PDGFR-β and negative reaction to endothelial markers) in newly-developing blood vessels reacted to vimentin, α-SMA, Thy-1 and A3, and occasionally to desmin, and that perifollicular dermal sheath cells in the wound periphery showed increased expressions for vimentin, Thy-1 and A3. There is considerable immunophenotypical similarity between myofibroblasts (expressing vimentin, α-SMA and Thy-1), pericytes (reacting to vimentin, α-SMA, Thy-1 and A3) in newly-developing blood vessels, and perifollicular dermal sheath cells (reacting to vimentin, Thy-1 and A3). Collectively, myofibroblasts in rat cutaneous fibrosis are characterized by vimentin, α-SMA and Thy-1 expressions, and the cells might be generated from the pericytes or perifollicular dermal sheath cells in the lineage of stroma-/bone marrow-stem cells.     

Preparation of a Monoclonal Antibody Specific for a 48-kDa Protein from Mitochondrial Nucleoids of the Yeast, Saccharomyces cerevisiae

Monoclonal antibodies (mAbs) were raised against yeast mitochondrialnucleoids (mtnucleoids). In an analysis by a combination ofimmunofluorescence microscopy and staining with 4',6-diamidino-2-phenylindole(DAPI), one of them, designated YMN-1, distinctly stained mtnucleoids,which were visible as dots, in spheroplasts and in isolatedmitochondria. However, staining of isolated mt-nucleoids wasrather weak. YMN-1 mAb recognized a 48-kDa protein in immunoblotsof both mitochondrial and mt-nucleoid proteins. The 48-kDa proteinwas a minor component of mt-nucleoid proteins and was separatedfrom extract of both mitochondria and mt-nucleoids by immunoamnitychromatography. The affinity-purified 48-kDa protein reassociatedwith mt-nucleoids when mixed with isolated mt-nucleoids, asmonitored by immunofluorescence microscopy. The results suggestthat a large amount of 48-kDa protein is associated with mt-nucleoidsin vivo, and that lysis of mitochondria by the treatment withdetergent releases a considerable amount of this protein frommt-nucleoids during the isolation of mt-nucleoids. (Received June 25, 1992; Accepted November 16, 1992)     

Stabilization of trypsin by modification with comb-shaped copolymers of poly(ethylene glycol) derivative and maleic anhydride

Summary Trypsin from bovine pancreas was coupled with copolymers of poly(ethylene glycol) derivative and maleic anhydride with the molecular weights of 13 kDa and 100 kDa (activated PM₁₃ and PM₁₀₀). The modified trypsins were more stable towards autolysis and heat- or urea-treatment than nonmodified trypsin. Stabilization of trypsin caused by the chemical modification with activated PMs is discussed in relation to the protein conformation.     

Effect of Methyl Substitution on Microbial Degradation of Linear Styrene Dimers by Two Soil Bacteria

The microbial degradation of 10 linear unsaturated dimers (I to IV) prepared from styrene and o-, m-, or p-methylstyrene was investigated with two soil bacteria, Alcaligenes sp. strain 559 and Pseudomonas sp. strain 419. The two strains decomposed styrene dimer I and all styrene-methylstyrene codimers II and III, but methylstyrene homodimers IV remained intact. The degradation rates of codimers II and III of o- and m-methylstyrenes were found to depend on both their structure and the strain used; i.e., Alcaligenes sp. strain 559 decomposed III faster than II, whereas the reverse order (II > III) was obtained with Pseudomonas sp. strain 419. In biodegradation by the former strain, the codimers were degraded faster in the presence of styrene dimer I than in its absence, but no such effect of dimer I was observed with the latter.     

Male aggression and the sexual behavior of Japanese monkeys

The factors that regulate male aggressive behavior towards females during the mating season and their relationship to the sexual behavior of Japanese monkeys were investigated. Observations were made on the Shiga A troop in Nagano Prefecture for 132 days during both the non-mating and mating seasons in three successive years. As a result, chasing towards females was observed in males older than 4 years. The frequencies of this type of behavior increased in the mating season. The chasing rank of the individual males did not correlate with the male dominance rank but with the tree-shaking rank. Chasing was directed not only at estrous females but also at non-estrous females. Pairs of both sexes in which chasing was observed, tended to have sexual interactions. Both hormonal and social factors should be considered in the regulation of chasing. The role of aggression in the formation of new male-female bonds in discussed.     

Molecular phylogeny of Neocalanus copepods in the subarctic Pacific Ocean, with notes on non-geographical genetic variations for Neocalanus cristatus

Monophylies of Neocalanus cristatus, Neocalanus plumchrus andNeocalanus flemingeri were revealed by nucleotide sequencesof mitochondrial 16S rRNA gene (410 bp) but not of nuclear 18SrDNA gene (1802 bp). Intraspecific variations in mitochondrial16S rRNA of N. cristatus collected from geographically distantregions were very low (<0.5%).