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1.
  • Inoda, Toshio, et al. (författare)
  • The Inheritance of Intrasexual Dimorphism in Female Diving Beetles (Coleoptera: Dytiscidae)
  • 2012
  • Ingår i: Zoological Science. - : Zoological Society of Japan. - 0289-0003. ; 29:8, s. 505-509
  • Tidskriftsartikel (refereegranskat)abstract
    • Many species of Dytiscus diving beetles exhibit intrasexual dimorphism, e. g., the elytra is smooth in some females and grooved in others. However, the expression of the grooves and whether they are a product of heredity or the environment remain unknown. One Japanese species, Dytiscus sharpi sharpi Wehncke, 1875, also shows female dimorphism, with grooved and smooth morphs, while D. sharpi validus Regimbart, 1899, only has a single morph (the grooved type). A hybrid of the two species should therefore provide a means of sorting out how the grooves are inherited. We found two independent wetlands of D. sharpi sharpi in Chiba Prefecture, Japan. One was a place where a high proportion of grooved females lived, and the others had high proportions of smooth females. After five to eight generations of beetles from two populations with different proportions of grooved females were reared under aquarium conditions constituting a common garden design, i.e., water temperature, water depth, and presence of a plant for oviposition, the differences remained. We mated smooth virgin females of D. sharpi sharpi with males of D. sharpi validus to obtain hybrid offspring. The elytral traits of the hybrid females produced only grooved forms. These results suggested that the female dimorphism is determined by genetics, and that the grooved morph was dominant over the smooth one, independent of environmental factors. In addition, the hybrid insects did not differ from the two subspecies insects in larval survivorship, pupation success, or sex ratio. They also showed neither morphological abnormality nor reduced survival.
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2.
  • Kajihara, H., et al. (författare)
  • Taxonomic Identity of a Tetrodotoxin-Accumulating Ribbon-worm Cephalothrix simula (Nemertea: Palaeonemertea): A Species Artificially Introduced from the Pacific to Europe
  • 2013
  • Ingår i: Zoological Science. - : Zoological Society of Japan. - 0289-0003. ; 30:11, s. 985-997
  • Tidskriftsartikel (refereegranskat)abstract
    • We compared the anatomy of the holotype of the palaeonemertean Cephalothrix simula (Iwata, 1952) with that of the holotypes of Cephalothrix hongkongiensis Sundberg, Gibson and Olsson, 2003 and Cephalothrix fasciculus (Iwata, 1952), as well as additional specimens from Fukue (type locality of C. simula) and Hiroshima, Japan. While there was no major morphological discordance between these specimens, we found discrepancies between the actual morphology and some statements in the original description of C. simula with respect to supposedly species-specific characters. Our observation indicates that these three species cannot be discriminated by the anatomical characters so far used to distinguish congeners. For objectivity of scientific names, topogenetypes of the mitochondrial cytochrome c oxidase subunit I (COI) sequences are designated for C. simula, C. hongkongiensis, and C. fasciculus. Analysis of COI sequence showed that the Hiroshima population can be identified as C. simula, which has been found in previous studies from Trieste, Italy, and also from both the Mediterranean and Atlantic coasts of the Iberian Peninsula, indicating an artificial introduction via (1) ballast water, (2) ship-fouling communities, or (3) the commercially cultured oyster Crassostrea gigas (Thunberg, 1793) brought from Japan to France in 1970s. Cephalothrix simula is known to be toxic, as it contains large amounts of tetrodotoxin (TTX). We report here that the grass puffer Takifugu niphobles (Jordan and Snyder, 1901)-also known to contain TTX-consumes C. simula. We suggest that the puffer may be able to accumulate TTX by eating C. simula.
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3.
  • Kang, X. X., et al. (författare)
  • Species Diversity of Ramphogordius sanguineus/Lineus ruber-like Nemerteans (Nemertea: Heteronemertea) and Geographic Distribution of R. sanguineus
  • 2015
  • Ingår i: Zoological Science. - : Zoological Society of Japan. - 0289-0003. ; 32:6, s. 579-589
  • Tidskriftsartikel (refereegranskat)abstract
    • Heteronemerteans, such as Lineus ruber, L. viridis, Ramphogordius sanguineus, R. lacteus, Riseriellus occultus, and Micrura varicolor, share many similar external characters. Although several internal characters useful for distinguishing these nemertean species have been documented, their identification is based mostly on coloration, the shape of the head, and how they contract, which may not be always reliable. We sequenced the mitochondrial COI gene for 160 specimens recently collected from 27 locations around the world (provisionally identified as the above species, according to external characters and contraction patterns, with most of them as R. sanguineus). Based on these specimens, together with sequences of 16 specimens from GenBank, we conducted a DNA-based species delimitation/identification by means of statistical parsimony and phylogenetic analyses. Our results show that the analyzed specimens may contain nine species, which can be separated by large genetic gaps; heteronemerteans with an external appearance similar to R. sanguineus/Lineus ruber/L. viridis have high species diversity in European waters from where eight species can be discriminated. Our 42 individuals from Vancouver Island (Canada) are revealed to be R. sanguineus, which supports an earlier argument that nemerteans reported as L. ruber or L. viridis from the Pacific Northwest may refer to this species. We report R. sanguineus from Chile, southern China, and the species is also distributed on the Atlantic coast of South America (Argentina). In addition, present analyses reveal the occurrence of L. viridis in Qingdao, which is the first record of the species from Chinese waters.
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4.
  • Mohammadi, Z., et al. (författare)
  • Molecular Phylogeny of the Subgenus Karstomys Reveals Genetic Signature of Post-glacial Colonization of Apodemus mystacinus (Rodentia: Muridae) in the Zagros Mountains from Different Refugia
  • 2021
  • Ingår i: Zoological Science. - : Zoological Society of Japan. - 0289-0003. ; 38:1, s. 72-81
  • Tidskriftsartikel (refereegranskat)abstract
    • Eastern broad-toothed field mouse, Apodemus mystacinus, is a rocky habitat dwelling rodent distributed in Asia Minor, the Levant, the Caucasus, and the Zagros Mountains. In this study, we investigated the phylogenetic relationship between different populations of A. mystacinus throughout its range, based on the mitochondrial cytb marker. Phylogenetic analyses revealed the existence of five separately evolving lineages within A. mystacinus, of which two previously unrecognized lineages were identified in the Zagros Mountains and the Levant. Divergence between two major clades of the subgenus Karstomys, corresponding to A. mystacinus and Apodemus epimelas, is inferred to coincide with the Messinian Salinity Crisis (Late Miocene), whereas the splits between major lineages of A. mystacinus are inferred to have occurred during the Pleistocene. Colonization of the Zagros may have occurred from different refugia via eastward migration of the Turkish population and then again by a more recent colonization from the Caucasus, after reopening of the land corridor between the Caucasus and the Zagros Mountains during the Holocene drought.
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8.
  • Sundberg, Per, 1950 (författare)
  • Thirty-five Years of Nemertean (Nemertea) Research-Past, Present, and Future
  • 2015
  • Ingår i: Zoological Science. - : Zoological Society of Japan. - 0289-0003. ; 32:6, s. 501-506
  • Tidskriftsartikel (refereegranskat)abstract
    • Developments in nemertean research over the last 35+ years are reviewed from a systematist's perspective. Nemertean systematics and classification, until fairly recently, was not based on explicit phylogenetic hypotheses, but rather on subjective assessment of "important characters". The first cladistic analyses appeared in the 1980s and were criticized at the time by leading researchers in nemertean systematics for not taking into account convergent evolution in ribbon worm morphology. The first molecular study involving the phylum Nemertea appeared in 1992, followed by reports later in the 1990s and early 2000s. Molecular information is now commonplace in nemertean research, and has changed our understanding of evolutionary relationships within the phylum, as well as our view on species and intraspecific variation. Challenges in nemertean systematics and taxonomy are discussed, with special emphasis on future species descriptions, and how to deal with a number of species names that in all likelihood never will be encountered again. Suggestions for how to deal with these challenges are discussed.
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10.
  • Yan, Xia, et al. (författare)
  • Heparanase Modulation of Early Growth Response Gene Expression
  • 2011
  • Ingår i: Zoological Science. - : Zoological Society of Japan. - 0289-0003 .- 2212-3830. ; 28:3, s. 189-194
  • Tidskriftsartikel (refereegranskat)abstract
    • Heparan sulfate (HS), a polysaccharide ubiquitously expressed in animals, is essential for development and homeostasis. Degradation of HS by heparanase, an endoglucuronidase, may affect pathophysiological function. Expression of the heparanase gene has been found elevated in a number of pathological conditions. The goal of this work was to investigate the impact of heparanase on expression of other genes. DNA microarray analysis revealed that 1, 042 genes in the cortex and 1,039 genes in the thalamus are up-or down-regulated more than 2-fold in mouse brain over-expresssing human heparanase. Of these genes, two of the early growth response genes, Egr1 and Egr2, are substantially upregulated in the cortex, but essentially unchanged in the thalamus. RTPCR analysis demonstrated a significant increase of Egr2, but a minor increase of Egr1, in human embryonic kidney cells stably overexpressing heparanase. The upregulated expression of Egr genes is also observed in hepatoma cells with upregulated expression of heparanase. Earlier studies reported that Egr1 induced heparanase expression; our findings suggest a possible reciprocal regulation of Egr and heparanase expression. Furthermore, overexpression of heparanase influenced expression of most genes involved in heparan sulfate proteoglycan biosynthesis, albeit to a different degree in the cortex and thalamus of the transgenic mice.
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