Cheek-pouch dispersal of seeds by Japanese monkeys (Macaca fuscata yakui) on Yakushima Island, Japan

Seed dispersal by Japanese monkeys (Macaca fuscata yakui) via cheek-pouch was studied in a warm temperate evergreen forest on Yakushima Island. Plant list was compiled based on a study during 1986–1995, of which troops of monkeys have been habituated without artificial feeding. We followed the well-habituated monkeys in 1993 and 1994 to observe the feeding behavior and their treatments of fruits and seeds, and collected seeds dispersed by monkeys to record the distance carried from the mother trees. We checked the difference of germination ratio between seeds dispersed via cheek-pouch and seeds taken from mother trees by sowing experiments. Seeds and acorns of 22 species were observed to be dispersed via cheek-pouch of monkeys. Among them, three species with acorns were never dispersed via feces, and 15 species with drupes were seldom dispersed via feces. Plant species of which seeds are dispersed only via cheek-pouch had larger seeds than those of dispersed both via cheek-pouch and via feces, and typically had only one or two seeds in a fruit. As for one of cheek-pouch dispersal species,Persea thunbergii, the mean distance when seeds were carried from the mother trees via cheek-pouch was 19.7 m, and the maximum distance was as long as 105 m although more than 80% of seeds were dispersed within 30 m from mother trees. And 82% of seeds dispersed via cheek-pouch germinated. The easy separation of seeds from other parts of the fruit seems to facilitate cheek-pouch dispersal more than dispersal via feces. Cheek-pouch dispersal by monkeys has possibly enhanced the natural selection for larger seeds which bring forth larger seedlings with high shade-tolerance. In conclusion, cheek-pouch dispersal by monkeys is quite an important mode for trees in the mature stand in a warm temperate evergreen forest on Yakushima Island.     

Direct expression in Escherichia coli and characterization of bovine adrenodoxins with modified amino-terminal regions

Four forms of bovine adrenodoxin with modified amino-termini obtained by direct expression of cDNAs in Escherichia coli are Ad(Met¹), Ad(Met⁻¹), Ad(Met⁻¹²), and Ad(Met⁶). The shoulder numbers represent this site of translation initiator Met at the amino-termini. The adrenodoxins, except for Ad(Met⁻¹), were purified from the cell lysate and the ratios of A₄₁₄-to-A₂₇₆ of the purified proteins were over 0.92. NADPH-cytochrome c reductase activities of the three forms of adrenodoxin in the presence of adrenodoxin reductase were the same as that of purified bovine adrenocortical adrenodoxin. However, as cytochrome P-450_SCC reduction catalyzed by Ad(Met⁰) was about 60% or that by Ad(Met¹), the contribution of the amino-terminal region for the electron transfer or binding to cytochrome P-450_SCC would need to be considered.     

Secretion of bovine alpha-lactalbumin into the milk of transgenic rats.

Bovine alpha-lactalbumin (b alpha LA) gene prepared by polymerase chain reaction was introduced into rat genomes by microinjection. Out of 17 transgenic rat lines, 11 secreted b alpha LA into their milk at concentrations higher than 0.2 micrograms/ml. Of these, three lines secreted b alpha LA at concentrations higher than those in bovine milk. The highest concentration of b alpha LA secreted into rat milk was 2,400 micrograms/ml.     

Skewed male reproductive success and pollen transfer in a small fragmented population of the heterodichogamous tree <Emphasis Type="Italic">Machilus thunbergii</Emphasis>

Heterodichogamy is defined as the presence of two flower morphs that exhibit the male and female functions at different times among individuals within a population. Heterodichogamy is regarded as an adaptation to promote outcrossing through enhanced inter-morph mating, together with a 1:1 morph ratio. However, in highly fragmented populations, the morph ratio may be more likely to be biased by stochastic events. In such a situation, individuals of a minority morph within a population are expected to have higher reproductive success than those of a majority morph, which may suffer from pollen shortages of the minority morph. In this paper, we evaluated mating patterns and male reproductive success in a highly fragmented population of Machilus thunbergii, a putative heterodichogamous evergreen laurel tree. Results of paternity analysis indicated that the selfing rate was not clearly different between the two morphs. In contrast, the proportion of intra-morph mating was higher in the majority-morph (MM) mother trees than in the minority-morph (MF) mother trees. Bayesian estimated male reproductive success indicated that male reproductive success was higher in minority-morph (MF) than in majority-morph (MM) mother trees. These findings indicate that (1) the majority morph mothers, suffering a shortage of the opposite morph pollen, could partly compensate for the reduced reproductive success by intra-morph mating rather than by selfing, and (2) negative-frequency dependent selection may be involved in the maintenance of the two morphs.     

Distribution of the CD4 Alleles in Sus scrofa Demonstrates the Genetic Profiles of Western Breeds and Miniature Pigs

Widely used antipig CD4 monoclonal antibodies (mAbs) fail to recognize CD4 alleles characteristic of miniature pig lines such as the National Institutes of Health (NIH) miniature pigs and microminipigs. We surveyed polymorphisms in the coding sequence of the porcine CD4 gene among Western and Oriental pig breeds and Japanese wild boars and investigated their distribution. Of the 13 alleles that we identified among the 47 animals, 2 in group I and 3 in group II were found exclusively in Western breed pigs. Group IV alleles, which included mAb-nonbinding alleles, were found frequently in Oriental breed pigs, suggesting that the mAb-nonbinding allele arose from the gene pool of Oriental pigs. Group IV alleles were also found in Duroc and Large White pigs, suggesting genetic inflow from Oriental pig breeds into Western breeds. Comparison of the CD4 sequences of species in Cetartiodactyla suggested that the group IV alleles in Sus scrofa occurred before the divergence of this species from the other artiodactyls. The different antibody specificities of the various CD4 alleles may facilitate the discrimination of T-cell populations in transplantation studies using miniature pigs. The significance of the preservation of CD4 polymorphisms to immune function in pigs warrants further investigation.     

Geographic population structure and sequence divergence in the mitochondrial DNA control region of the Japanese wild boar (Sus scrofa leucomystax), with reference to those of domestic pigs

Mitochondrial DNA (mtDNA) control regions from 40 Japanese wild boars were examined by direct sequencing after amplification by PCR. From the DNA sequences obtained, we found eight haplotypes, whose differences arose via transitions. The geographical distribution of these different haplotypes indicated that wild boar populations inhabited limited areas and that there was some restricted gene flow between local populations. Eight mtDNA haplotypes from Eastern and Western domestic pigs and the Ryukyu wild boar were also analyzed as references to those from Japanese wild boars. The cluster analyses of the control-region sequences showed that those from Japanese wild boards belong to the Asian type as do those from Eastern domestic pigs and the Ryukyu wild boar, which differed from the European type (Western domestic pigs).     

Glutathione Efflux from Cultured Astrocytes

Abstract: The characteristics and kinetics of GSH efflux from the monolayer culture of rat astrocytes were investigated. GSH efflux was dependent on temperature, with a Q ₁₀ value of 2.0 between 37 and 25°C. The GSH efflux rate showed a hyperbolic dependency on the intracellular GSH concentration. The data were fitted well to the Michaelis-Menten model, giving the following kinetic parameter values: K _m = 127 nmol/mg of protein; V _max = 0.39 nmol/min/mg of protein. p -Chloromercuribenzenesulfonic acid, a thiol-reactive agent impermeable to the cell membrane, lowered the GSH efflux rate by 25% without affecting the intracellular GSH content. These results suggest that a carrier is involved in the efflux of GSH. The GSH content of cultured astrocytes showed a marked increase when the cells were exposed to insults, such as sodium arsenite, cadmium chloride, and glucose/glucose oxidase that lead to the generation of hydrogen peroxide. The increase in GSH content was attributed to the induction of the cystine transport activity by the agents. Although the intracellular GSH concentration and GSH efflux were increased, the kinetics of GSH efflux were not affected by those agents that imposed the oxidative stress. Because the K _m value is very large, it is suggested that astrocytes release GSH depending on their GSH concentration in a wide range.     

Prediction of the Coding Sequences of Unidentified Human Genes. III. The Coding Sequences of 40 New Genes (KIAA0081-KIAA0120) Deduced by Analysis of cDNA Clones from Human Cell Line KG-1

We isolated full-length cDNA clones from size-fractionated cDNAlibraries of human immature myeloid cell line KG-1, and thecoding sequences of 40 genes were newly predicted. A computersearch of the GenBank/EMBL databases indicated that the sequencesof 14 genes were unrelated to any reported genes, while theremaining 26 genes carried some sequences with similaritiesto known genes. Significant transmembrane domains were identifiedin 17 genes, and protein motifs that matched those in the PROSITEmotif database were identified in 11 genes. Northern hybridizationanalysis with 18 different cells and tissues demonstrated that10 genes were apparently expressed in a cell-specific or tissue-specificmanner. Among the genes predicted, half were isolated from themedium-sized cDNA library and the other half from the small-sizedcDNA library, and their average sizes were 4 kb and 1.4 kb,respectively. As judged by Northern hybridization profiles,small-sized cDNAs appeared to be expressed more ubiquitouslyand abundantly in various tissues, compared with that of medium-sizedcDNAs.     

Trypsin-sensitive and -resistant components in human T-cell membranes required for syncytium formation by human T-cell lymphotropic virus type 1-bearing cells.

Human T-cell lymphotropic virus type 1 (HTLV-1) envelope proteins play an important role in viral entry into target cells. In a syncytium formation assay consisting of a coculture of HTLV-1-bearing cells and target cells, mature gp46 and gp21 proteins each inhibited syncytium formation induced by HTLV-1-bearing cells. Experiments with 125I-labeled proteins showed that 125I-gp46 bound specifically with MOLT-4 target cells even in the presence of large amounts of gp21, whereas 125I-gp21 binding to target cells was completely blocked in the presence of large amounts of gp46. These observations suggest that HTLV-1 envelope proteins in syncytium formation interact with at least two components, which are located close to each other on the cell membrane. We isolated two components from MOLT-4 cell lysate, using Sepharose 4B columns coupled with peptides corresponding to amino acids 197 to 216 and 400 to 429, respectively, of the envelope protein. One is a trypsin digestion-sensitive component of approximately 34 to 35 kDa, which interacts specifically with gp46. The other is a nonprotein component, which interacts with gp21. This component was destroyed by sodium periodate oxidation and was partitioned into the methanol-chloroform phase. These observations suggest that these two components play an important role in HTLV-1 entry into target cells via membrane fusion.     

Assignment of Human Membrane-type Matrix Metalloproteinase-2 (MT2-MMP) Gene to 16q12 by FISH and PCR-based Human/Rodent Cell Hybrid Mapping Panel Analysis

A new group of matrixmetalloproteinase with a potential membranedomain was reported as membranetype matrixmetalloproteinases(MT-MMPs), and the gene coding for one of them, MT2-MMP, wasrecently cloned from a human lung cDNA library. To predict itsphysiological functions by the relation to the genetic disordersmapped on the chromosomes, the chromosomal location of the humanMT2-MMP gene was examined by fluorescence in situ hybridization(FISH) and PCR-based analysis with human/rodent hybrid cellmapping panels, and it was assigned to 16q12.