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KOICHIRO KAMEYAMA CHIE SAKAI SAKAE KUGE SHIGEO NISHIYAMA YASHUSI TOMITA SHOSUKE ITO KAZUMASA WAKAMATSU VINCENT J. HEARING 《Pigment cell & melanoma research》1995,8(2):97-104
The expression of various melanogenic proteins, including tyrosinase, the tyrosinase-related proteins 1 (TRP1) and 2 (TRP2/DOPAchrome tautomerase), and the silver protein in human melanocytes was studied in six different human melanoma cell lines and compared to a mouse derived melanoma cell line. Analysis of the expression of tyrosinase, TRP1, TRP2, and the silver protein using flow cytometry revealed that in general there was a positive correlation between melanin formation and the expression of those melanogenic enzymes. Although several of the melanoma cell lines possessed significant activities of TRP2, the levels of DOPAchrome tautomerase in extracts of human cells were relatively low compared to those in murine melanocytes. Melanins derived from melanotic murine JB/MS cells, from melanotic human Ihara cells and HM-IY cells, from sepia melanin, and from C57BL/6 mouse hair were chemically analyzed. JB/MS cells, as well as Ihara cells and HM-TY cells, possessed significant amounts of 5,6-dihydroxyindole-2-carboxylic acid (DHICA) derived melanins, this being dependent on the activity of TRP2. Kinetic HPLC assays showed that 5,6-dihydroxyindole (DHI) produced during melanogenesis was metabolized quickly to melanin in pigmented KHm-1/4 cells, whereas DHI was stable in amelanotic human SK-MEL-24 cells. A melanogenic inhibitor that has been purified from SK-MEL-24 cells that suppressed oxidation of DHI in the presence or absence of tyrosinase, but had no effect on DHICA oxidation. The sum of these results suggest that the expression of melanogenic enzymes as well as the activity of a melanogenic inhibitor are critical to the production of melanin synthesis in humans. 相似文献
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NOBUYUKI MIZUNO MASANORI YAMASAKI YOSHIHIRO MATSUOKA TAIHACHI KAWAHARA SHIGEO TAKUMI 《Molecular ecology》2010,19(5):999-1013
Aegilops tauschii Coss. is the D‐genome progenitor of hexaploid wheat. Aegilops tauschii, a wild diploid species, has a wide natural species range in central Eurasia, spreading from Turkey to western China. Amplified fragment length polymorphism (AFLP) analysis using a total of 122 accessions of Ae. tauschii was conducted to clarify the population structure of this widespread wild wheat species. Phylogenetic and principal component analyses revealed two major lineages in Ae. tauschii. Bayesian population structure analyses based on the AFLP data showed that lineages one (L1) and two (L2) were respectively significantly divided into six and three sublineages. Only four out of the six L1 sublineages were diverged from those of western habitats in the Transcaucasia and northern Iran region to eastern habitats such as Pakistan and Afghanistan. Other sublineages including L2 were distributed to a limited extent in the western region. Subspecies strangulata seemed to be differentiated in one sublineage of L2. Among three major haplogroups (HG7, HG9 and HG16) previously identified in the Ae. tauschii population based on chloroplast variation, HG7 accessions were widely distributed to both L1 and L2, HG9 accessions were restricted to L2, and HG16 accessions belonged to L1, suggesting that HG9 and HG16 were formed from HG7 after divergence of the first two lineages of the nuclear genome. These results on the population structure of Ae. tauschii and the genealogical relationship among Ae. tauschii accessions should provide important agricultural and evolutionary knowledge on genetic resources and conservation of natural genetic diversity. 相似文献
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SHIGEO TAKENAKA TOMOHIRO KONDO SONBOL NAZERI YOSHIYUKI TAMURA MASAO TOKUNAGA SHINGO TSUYAMA KAZUTAKA MIYATAKE YOHSIHISA NAKANO 《The Journal of eukaryotic microbiology》1997,44(6):609-613
ABSTRACT. The photosynthetic protozoon Euglena gracilis, accumulated a large amount of trehalose in the cells under salt or osmotic stresses. Radioactivity of [14C] paramylon, a β-1,3-polyglucan which was stored in the cells of E. gracilis. was degraded rapidly and this radioactivity was almost stoichiometrically incorporated into trehalose. The interconversion of trehalose from paramylon by salt or osmotic stresses was dependent on the concentrations or osmotic pressures, suggesting that E. gracilis accumulate trehalose as an osmoprotectant. After the removal of salt or osmotic stresses, trehalose was gradually degraded, however, it was not converted into paramylon. 相似文献
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Abstract: The scalpelliform genus Stramentum is described from upper Turonian–Coniacian (Upper Cretaceous) strata in the Mikasa area, Hokkaido (Japan), documenting the first record of the genus from the north-west Pacific Realm. The single articulated skeleton, which is horizontally embedded in a dark grey laminated mudstone, is specifically indeterminate because capitular plates are missing. However, peduncular morphology resembles that of S. ( S .) pulchellum (Sowerby Jr), which has been described from the Cenomanian–Turonian of Europe. The present record from Japan demonstrates that this cirripede genus had a wider geographic distribution than previously assumed during the youngest phase of its radiation. 相似文献
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HAJIME YOSHINO KYLE N. ARMSTRONG MASAKO IZAWA JUN YOKOYAMA MASAKADO KAWATA 《Molecular ecology》2008,17(23):4978-4991
The origin and meaning of echolocation call frequency variation within rhinolophid bats is not well understood despite an increasing number of allopatric and sympatric examples being documented. A bimodal distribution of mean regional call frequency within the Okinawa‐jima Island population of Rhinolophus cornutus pumilus (Rhinolophidae) provided a unique opportunity to investigate geographic call frequency variation early in its development. Individual resting echolocation frequencies, partial mitochondrial DNA D‐loop sequences and genotypes from six microsatellite loci were obtained from 288 individuals in 11 colonies across the entire length of the island, and nearby Kume‐jima Island. Acoustic differences (5–8 kHz) observed between the north and south regions have been maintained despite evidence of sufficient nuclear gene flow across the middle of the island. Significant subdivision of maternally inherited D‐loop haplotypes suggested a limitation of movement of females between regions, but not within the regions, and was evidence of female philopatry. These results support a ‘maternal transmission’ hypothesis whereby the difference in the constant frequency (CF) component between the regions is maintained by mother–offspring transmission of CF, the restricted dispersal of females between regions and small effective population size. We suggest that the mean 5–8 kHz call frequency difference between the regions might develop through random cultural drift. 相似文献
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YOSHINO K KONDO A KUMA N KITAOKA M 《Japanese journal of medical science & biology》1958,11(1-2):59-71