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1.
SATOSHI TANAKA HIDEAKI TOJO KYOKO KASAI TORU SAWASAKI CHIKASHI TACHI 《Pigment cell & melanoma research》1994,7(3):152-157
Dominant black-eyed white phenotypes are one of the most commonly observed traits in domestic animals. Their genetic control mechanisms, however, have not been elucidated. As the first step to approach the problem, we examined histologically the patterns of the distribution of pigment cells in Shiba goats (two each of day-73-postcoitum and day-112-postcoitum fetuses, and a 15-week-old kid) with the dominant black-eyed white phenotype. Melanocytes were present and fully pigmented in the choroid and the sclera of eyes, as well as in dorsal skin epidermis of the fetuses and of the kid. Melanocytes were also found in approximately 6% of the hair bulbs in the fetal dorsal skin, while the rest (94%) lacked them. Hair follicles of the kid did not harbor melanocytes except for some in the early anagen stage. The results suggest that the survival of melanocytes was inhibited specifically in the hair follicles of the Shiba goat with the dominant black-eyed white phenotype and that the ostensibly similar phenotypes in the Shiba goat and in the SI or W mutants of the mouse, where melanocytes die en route to the hair bulbs, are regulated by different mechanisms. 相似文献
2.
The social system of the Rufous Vanga Schetba rufa was studied in a deciduous dry forest in Ampijoroa, western Madagascar. The species lived in groups of two to four individuals. Groups typically contained one adult female, one or two adult males and sometimes a (presumed) immature. All group members appeared to defend the territory. The presumed immatures had spotted throats and were smaller than adults in body size. They helped feed young and guard the nest but did not incubate or brood. 相似文献
3.
Cytokinin activities of 6-benzoylamino-1, 6-benzoylamino-3-, 6-pentanoylamino-1- and 6-pentanoylamino-3-deazapurines and their corresponding purine analogs, 6-benzoylaminopurine and 6-pentanoylaminopurine, were examined using five bioassay systems, tobacco callus growth, bud formation on tobacco callus, lettuce seed germination, fresh weight increase of radish cotyledons and retardation of chlorophyll degradation in radish cotyledons. 6-Benzoylamino- and 6-pentanoylamino-1-deazapurines showed stronger cytokinin activity than their corresponding purine analogs in all bioassays used. In tobacco callus growth, 6-benzoylamino-1-deazapurine was nearly as active as zeatin, one of the most active adenylate cytokinins. On the other hand, 6-benzoylamino- and 6-pentanoylamino-3-deazapurines were as active as or less active than corresponding purine analogs. 相似文献
4.
SHINICHIRO WADA SATOSHI CHIBA 《Biological journal of the Linnean Society. Linnean Society of London》2011,102(3):686-693
Because land snails inhabiting the seashore are most likely to be carried by ocean currents or by attaching to seabirds, land snail fauna on oceanic islands include species derived from the mainland ancestors inhabiting the seashore. If habitat use of the island descendants is constrained by the ecology of the mainland ancestor, the island species that moved from the coastal habitat to the inland habitat may still be restricted to relatively exposed microhabitats with high pH, calcium carbonate‐rich substrates, and poor litter cover. We tested this hypothesis by investigating the association between environmental conditions and species diversity of seashore‐derived species of the endemic land snails on the oceanic Hahajima Island (Ogasawara Islands). Seashore‐derived species showed higher species richness on limestone outcrops than non‐limestone areas, whereas the other species showed no significant increase in species richness in limestone outcrops. There was a higher proportion of seashore‐derived species on the limestone ridges than on the soil of dolines, even in the limestone area. Accordingly, the species derived from the seashore of the mainland are restricted to microhabitats with poor vegetation cover, poor litter cover, high pH, and calcium carbonate‐rich substrates, which supports the hypothesis that the inland species on an island derived from the mainland seashore still prefer environments similar to the seashore. In addition, the seashore‐derived species on the limestone outcrop include cave‐dwellers lacking functional eyes. This suggests that the probability of colonizing a cave environment is restricted to seashore‐derived species. The findings obtained in the present study suggest that habitat use of the ancestral lineages can constrain habitat use of the descendants, even in the oceanic islands with depauperate fauna. This bias in the species composition on the limestone outcrop constrains lineages that can colonize and adapt to the inside of caves, and therefore, habitat use of the ancestral lineages affects the ability of descendant lineages to colonize novel habitats. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 686–693. 相似文献
5.
Trillium camschatcense is a herbaceous perennial plant distributed in Hokkaido and northern Honshu, Japan. Geographical variations in the breeding system (partial selfing or obligate outcrossing) are reported in the populations of Hokkaido. We isolated six polymorphic microsatellite loci from this species. The number of allele per locus ranged from four to 12, whereas the expected heterozygosities ranged from 0.69 to 0.83. These markers may allow further investigations to reveal the evolutionary and ecological processes of mating system in T. camschatcense. 相似文献
6.
RICKARD IGNELL SATOSHI OKAWA JAN‐ERIC ENGLUND SHARON R. HILL 《Physiological Entomology》2010,35(3):274-286
To investigate feeding‐related decisions in Aedes aegypti (L.), adults are presented with simple diets of paired gustatory stimuli conveying information concerning energy content, nutrient richness, osmotic balance and food toxicity in a two‐diet matrix assay. Assessment of mosquito gut contents indicates that both sexes accept single sugar diets in a dose‐dependent manner. When presented with a choice between two different yet equimolar sugar solutions, more individuals of both sexes accept the disaccharides, sucrose and trehalose, than the monosacharrides, fructose and glucose. The combination of pyranose and furanose sugars in solution, either physically associated (as in sucrose) or present as monomers (as glucose and fructose), is accepted over solutions containing a single sugar moiety. Using the two‐diet matrix assay, mosquito diet‐choice is also tested between two equimolar sucrose ‘driver’ solutions in which one is presented with various concentrations of another potential feeding cue ‘test’ compound (i.e. each of the 20 naturally‐occurring amino acids, sodium chloride, quinine or caffeine). Diet‐choice between the ‘driver’ sucrose‐only solution and the solution of the ‘driver’ sucrose containing a ‘test’ amino acid is influenced by sex, amino acid concentration and sucrose concentration. There is also an example of synergism between the diet components, leucine and sucrose. Mosquitoes demonstrate a dose‐dependent acceptance of sucrose‐only diets over sodium chloride‐containing sucrose when presented together. Interestingly, the sucrose‐only diet is accepted by more mosquitoes than all concentrations of the saline‐containing sucrose diets except those approximately isotonic to mosquito haemolymph, at which concentration mosquitoes show no clear choice between the diets. More individuals of both sexes accept sucrose‐only diets than the diets of caffeine‐containing sucrose in a dose‐dependent manner. Only females, however, respond to quinine‐containing sucrose diets and modulate this behaviour in relation to the energetic reward: more females imbibed quinine‐containing sucrose at the higher sucrose concentration (1 m ). A systematic characterization of diet selection behaviour of A. aegypti is presented for 27 putative feeding cues potentially involved in nectar/honeydew feeding. This study will be used as a basis from which to investigate further the mosquito's assessment of food quality and ultimately host choice. 相似文献
7.
8.
Masayuki OKAUE Kazunori YAMAMOTO Yoshifumi TOUYAMA Takeshi KAMEYAMA Mamoru TERAYAMA Takashi SUGIYAMA Kyouzou MURAKAMI Fuminori ITO 《Entomological Science》2007,10(4):337-342
The distribution of the Argentine ant, Linepithema humile, was investigated in 65 cities or towns along the Seto Inland Sea, western Japan in 2003–2005. Our results include all available information of their distribution in Japan until 2005. Argentine ants have invaded Aichi Prefecture (Tahara‐shi), Hyogo Prefecture (Kobe‐shi), Hiroshima Prefecture (Hiroshima‐shi, Fuchu‐cho, Hatsukaichi‐shi, Ono‐cho and Otake‐shi), and Yamaguchi Prefecture (Iwakuni‐shi and Yanai‐shi). The most widespread distribution was found around Hatsukaichi‐shi including the westernmost part of Hiroshima‐shi and the easternmost of Ono‐cho. 相似文献
9.
10.
VINCENT J. HEARING KATSUHIKO TSUKAMOTO KAZUNORI URABE KOICHIRO KAMEYAMA PAUL M. MONTAGUE IAN J. JACKSON 《Pigment cell & melanoma research》1992,5(5):264-270
Several genes critical to the regulation of melanin production in mammals have recently been cloned and characterized. They map to the albino, brown, and slaty loci in mice, and encode proteins with similar structures and features, but with distinct catalytic capacities. The albino locus encodes tyrosinase, an enzyme with three distinct catalytic activities—tyrosine hydroxylase, 3,4-dihydroxyphenylalanine (DOPA) oxidase and DHI (5,6-dihydroxyindole) oxidase. The brown locus encodes TRP-l (tyrosinase-related protein-I), which has the same, but greatly reduced, catalytic potential. The slaty locus encodes TRP-2, another tyrosinase related-protein, which has DOPAchrome tautomerase activity. In this study we have examined the enzymatic interactions of these proteins, and their regulation by a novel melanogenic inhibitor. We observed that tyrosinase activity is more stable in the presence of TRP-l and/or TRP-2, but that the catalytic function of TRP-2 is not affected by the presence of TRP-1 or tyrosinase. Other factors also may influence melanogenesis and a unique melanogenic inhibitor suppresses tyrosinase and DOPAchrome tautomerase activities, but does not affect the spontaneous rate of DOPAchrome decarboxylation to DHI. The results demonstrate the catalytic functions of these proteins and how they stably interact within a melanogenic complex in the melanosome to regulate the quantity and quality of melanin synthesized by the melanocyte. 相似文献