Update of mouse microsatellite database of Japan (MMDBJ).

We updated a database of microsatellite marker polymorphisms found in inbred strains of the mouse, most of which were derived from the wild stocks of four Mus musculus subspecies, M. m. domesticus, M. m. musculus, M. m.castaneus and M. m. molossinus. The major aim of constructing this database was to establish the genetic status of these inbred strains as resources for linkage analysis and positional cloning. The inbred strains incorporated in our database are A/J, C57BL/6J, CBA/J, DBA/2J, SM/J, SWR/J, 129Sv/J, MSM/Ms, JF1/Ms, CAST/Ei, NC/Nga, BLG2/Ms, NJL/Ms, PGN2/Ms, SK/CamEi and SWN/Ms, which have not or have only been poorly incorporated in the Whitehead Institute/MIT (WI/MIT) microsatellite database. The number of polymorphic microsatellite loci incorporated in our database is over 1,000 in all strains, and the URL site for our database is located at http:// www.shigen.nig.ac.jp /mouse/mmdbj/mouse.html.     

A morphological study and hybridization analysis of Caloglossa leprieurii (Ceramiales, Rhodophyta) from Japan, Singapore and Australia

Morphological and hybridization experiments were performed on Caloglossa leprieurii (Montagne) J. Agardh collected from Japan, Singapore and Australia in order to evaluate taxonomic characters of this species. Within C. leprieurii at least four mating groups were recognized from the Indo-Pacific region. These mating groups could be characterized by the blade width at the inter-node and the cell-row numbers on the opposite side derived from the first axial cell at the main axis, though these properties showed a certain variability even in the same plant under both field and culture conditions. The phylogenetic relationship and geographic distribution of the four mating groups are discussed.     

Morphological shifts in island-dwelling birds: the roles of generalist foraging and niche expansion

Abstract Passerine birds living on islands are usually larger than their mainland counterparts, in terms of both body size and bill size. One explanation for this island rule is that shifts in morphology are an adaptation to facilitate ecological niche expansion. In insular passerines, for instance, increased bill size may facilitate generalist foraging because it allows access to a broader range of feeding niches. Here we use morphologically and ecologically divergent races of white-eyes (Zosteropidae) to test three predictions of this explanation: (1) island populations show a wider feeding niche than mainland populations; (2) island-dwelling populations are made up of individual generalists; and (3) within insular populations there is a positive association between size and degree of foraging generalism. Our results provide only partial support for the traditional explanation. In agreement with the core prediction, island populations of white-eye do consistently display a wider feeding niche than comparative mainland populations. However, observations of individually marked birds reveal that island-dwelling individuals are actually more specialized than expected by chance. Additionally, neither large body size nor large bill size are associated with generalist foraging behavior per se. These latter results remained consistent whether we base our tests on natural foraging behavior or on observations at an experimental tree, and whether we use data from single or multiple cohorts. Taken together, our results suggest that generalist foraging and niche expansion are not the full explanation for morphological shifts in island-dwelling white-eyes. Hence, we review briefly five alternative explanations for morphological divergence in insular populations: environmental determination of morphology, reduced predation pressure, physiological optimization, limited dispersal, and intraspecific dominance.     

Hantavirus-specific CD8(+)-T-cell responses in newborn mice persistently infected with Hantaan virus

The relationship between virus-specific CD8(+)-T-cell responses and viral persistence was studied in mice by using Hantaan virus (HTNV). We first established a simple method for measuring levels of virus-specific CD8(+) T cells by flow cytometry. Next, to produce a mouse model of persistent HTNV infection, newborn mice were inoculated subcutaneously within 24 h of birth with 1 or 0.1 50% newborn mouse lethal dose of HTNV. All mice that escaped lethal infection were persistently infected with HTNV until at least 30 days after virus inoculation and had no virus-specific CD8(+) T cells producing gamma interferon (IFN-gamma). Subsequently, the virus was eliminated from some of the mice, depending on the appearance of functional virus-specific CD8(+) T cells, which have the ability to produce IFN-gamma and tumor necrosis factor alpha (TNF-alpha) and have cytotoxic activity. Neutralizing antibodies were detected in all mice, regardless of the presence or absence of virus. In the acute phase, which occurs within 30 days of infection, IFN-gamma-producing HTNV-specific CD8(+) T cells were detected on day 15 after virus inoculation. However, TNF-alpha production and the cytotoxic activity of these specific CD8(+) T cells were impaired and HTNV was not removed. Almost all of these specific CD8(+) T cells disappeared by day 18. These results suggest that functional HTNV-specific CD8(+) T cells are important for clearance of HTNV.     

Herpes Simplex Virus-Induced Expression of 70 kDa Heat Shock Protein (HSP70) Requires Early Protein Synthesis But Not Viral DNA Replication

The major 70 kDa heat shock protein (HSP70), which is scarcely expressed in unstressed rodent cells, was apparently induced by infection with herpes simplex virus (HSV). Infection with HSV types 1 and 2 elevated HSP70 mRNA levels within 4 hr post-infection. HSP70 synthesis and accumulation increased in HSV-infected cells. Irradiation of HSV with UV-light abolished the ability to induce HSP70 mRNA. Inhibitors of viral DNA synthesis did not affect the induction of HSP70 in infected cells. Protein synthesis within 2 hr after infection was necessary for HSP70 induction.     

Promotive Effect of C18-Unsaturated Fatty Acids on the Abscission of Bean Petiole Explants

The abscission-promoting effects of C₁₈-unsaturated fatty acidswere studied in bean (Phaseolus vulgaris L. cv. Masterpiece)petiole explants with the junction between the petiole and thepulvinus in the primary leaves in the light. Linolenic, linoleicand oleic acids promoted the abscission of the explants in thelight. Linolenic acid was the most effective among the compoundstested and its promotive effect was evident without any accompanyingincrease in the production of ethylene from the explants, ascompared with non-treated explants. Linolenic acid is easilyconverted to its hydroperoxide during the incubation with explants,as indicated by the formation of the conjugated diene and thegeneration of ethane. The production of ethylene from the explantstreated with linolenic acid was completely inhibited by theaddition of aminoethoxyvi-nylglycine (AVG), but large amountsof ethane were still generated. The promotive effect of linolenicacid was almost eliminated by the addition of scavengers offree radicals. Hydrogen peroxide and tert-butyl hydroperoxidepromoted abscission in the light. From these results, we concludedthat the abscission-promoting effect of linolenic acid are notmediated by the effect of ethylene but by the effect of itshydroperoxide, while the well-established pathway for the biosynthesisof ethylene from S-adenosylmethionine to ethylene, via 1-aminocyclopropane-l-carboxylicacid (ACC), was apparently operative. (Received May 1, 1991; Accepted July 10, 1991)     

Melatonin Inhibits Embryonic Salivary Gland Branching Morphogenesis by Regulating Both Epithelial Cell Adhesion and Morphology

Many organs, including salivary glands, lung, and kidney, are formed by epithelial branching during embryonic development. Branching morphogenesis occurs via either local outgrowths or the formation of clefts that subdivide epithelia into buds. This process is promoted by various factors, but the mechanism of branching morphogenesis is not fully understood. Here we have defined melatonin as a potential negative regulator or “brake” of branching morphogenesis, shown that the levels of it and its receptors decline when branching morphogenesis begins, and identified the process that it regulates. Melatonin has various physiological functions, including circadian rhythm regulation, free-radical scavenging, and gonadal development. Furthermore, melatonin is present in saliva and may have an important physiological role in the oral cavity. In this study, we found that the melatonin receptor is highly expressed on the acinar epithelium of the embryonic submandibular gland. We also found that exogenous melatonin reduces salivary gland size and inhibits branching morphogenesis. We suggest that this inhibition does not depend on changes in either proliferation or apoptosis, but rather relates to changes in epithelial cell adhesion and morphology. In summary, we have demonstrated a novel function of melatonin in organ formation during embryonic development.     

Origins of mouse inbred strains deduced from whole-genome scanning by polymorphic microsatellite loci

Microsatellite loci are uniformly distributed at approximately 100-kbp intervals on all chromosomes except the chromosome Y, and genetic information about more than 9000 loci and high-throughput polymorphism analysis are now available. Taking advantage of these properties, we carried out whole-genome scanning using eight common inbred strains (CIS) of laboratory mice, including A/J, C57BL/6J, CBA/J, DBA/2J, SM/J, SWR/J, NC/Nga, and 129/SvJ, and eight wild-derived inbred strains (WIS), BGL2/Ms, CAST/Ei, JF1/Ms, MSM/Ms, NJL/Ms, PGN2/Ms, SK/CamEi, and SWN/Ms. We selected and located 1226 informative loci at 1.2-cM average intervals on all of the chromosomes of the 16 strains and compared the polymorphisms of the eight CIS with those from the eight WIS as subspecies representatives. More than 50% of the loci can be identified as WIS (therefore, subspecies-specific) alleles in the CIS genomes. We also discovered that the CIS chromosomes form a mosaic structure with an average ratio of domesticus to non-domesticus alleles of 3:1. Furthermore, the domesticus alleles were present much more frequently on the CIS chromosome X than on their autosomes, suggesting that successive backcrossing of non-domesticus stocks to domesticus stocks had been undergone at the beginning of CIS history.     

Purification of GTP-binding proteins from bovine brain membranes. Identification of heterogeneity of the alpha-subunit of Go proteins

Using high-resolution Mono Q column chromatography, we purified 6 distinct peaks of GTP-binding proteins from bovine brain membranes. Five of them consisted of 3 polypeptides with alpha beta gamma-subunits and served as the substrate of islet-activating protein (IAP), pertussis toxin. The other one was purified as alpha-subunit alone and was also ADP-ribosylated by IAP in the presence of beta gamma-subunits. When each alpha-subunit was characterized by immunoblot analysis using various antibodies with defined specificity, the two of them were identified as Gi-1 and Gi-2, and other 4 appeared to be Go or Go-like G proteins. The alpha-subunits of immunologically Go-like proteins were apparently distinguishable from one another on elution profiles from the Mono Q column. Thus, there was a heterogeneity of the alpha-subunit of Go in the brain membranes.     

Purification, characterization, and gene analysis of cellulase (Cel8A) from Lysobacter sp. IB-9374

An enzyme that has both beta-1,4-glucanase and chitosanase activities was found in the culture medium of the soil bacterium Lysobacter sp. IB-9374, a high lysyl endopeptidase-producing strain. The enzyme was purified to homogeneity from the culture filtrate using five purification steps and designated Cel8A. The purified Cel8A had a molecular mass of 41 kDa, as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A pH optimum of 5.0 was found for the beta-1,4-glucanase activity, and pH optima of 5.0 and 7.0 were found for the chitosanase activity. Nucleotide sequencing of the Cel8A gene yielded a deduced amino acid sequence that comprises a 33-amino acid, N-terminal signal peptide and a mature enzyme consisting of a 381-residue polypeptide with a predicted molecular mass of 41,241 Da. The amino acid sequence of the Cel8A, which contains the catalytic module of glycosyl hydrolase family 8, is homologous to beta-1,3-1,4-D-glucanase from Bacillus circulans WL-12 and endoglucanase N-257 from B. circulans KSM-N257.