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1.
Young-Jun Park Tomotaro Nishikawa Norihiko Tomooka Kazuhiro Nemoto 《Molecular breeding : new strategies in plant improvement》2012,30(1):511-520
Polymorphisms at the Waxy locus of Amaranthus caudatus L. collected from a wide range of regions were used to investigate genetic diversity and mutation sites. A comparison of the Waxy locus revealed a very high level of sequence conservation. This result clearly showed low environmental and evolutionary variability in the Waxy gene. We also performed screening to confirm the mutation sites in the coding sequences of all accessions. The results indicate that one insertion in the coding region of Waxy genes was responsible for the change in perisperm starch leading to the waxy phenotype in all accessions of this species, and thus that a single mutation event altered the regulation of the Waxy gene during the domestication of this crop. In addition, phylogenetic analysis showed that waxy phenotypes within each of three species, A. caudatus, A. cruentus and A. hypochondriacus, originated separately or differentiated from nonwaxy phenotypes of each species through a single mutational event (i.e., a frame shift or base substitution). We also compared obvious structural features of the coding sequence of waxy and nonwaxy phenotypes with those of low-amylose phenotypes in A. caudatus. The Waxy coding sequences of low-amylose phenotypes do not show polymorphisms and are identical with those of waxy phenotypes. This could mean that there is another gene that encodes a key enzyme responsible for amylose synthesis as the elementary quantity in tissues other than perisperm in A. caudatus. 相似文献
2.
Kuniyoshi Masuda Tomio Kawata Kenji Takumi Takemi Kinouchi 《Microbiology and immunology》1980,24(6):507-513
The ultrastructure of a hexagonal array in the exosporium from spores of a highly sporogenic mutant of Clostridium botulinum type A strain 190L was studied by electron microscopy of negatively stained exosporium fragments using optical diffraction and filtration. The exosporium was composed of three or more lamellae showing an equilateral, hexagonal periodicity. Images of the single exosporium layer from which the noise had been filtered optically revealed that the hexagonally arranged, morphological unit of the exosporium was composed of three globular subunits about 2.1 nm in diameter which were arranged at the vertices of an equilateral triangle with sides of about 2.4 nm. The morphological units were arranged with a spacing of about 4.5 nm. The adjacent globular subunits appeared to be interconnected by delicate linkers. 相似文献
3.
Nontoxigenic variants were isolated from Clostridium botulinum type A strain 190L after treatment with detergents such as deoxycholate, sodium dodecyl sulfate, Tween 80 and Brij-58. Deoxycholate was most effective for obtaining the variants. The variants exhibited a markedly increased frequency of sporulation compared with the oligosporogenic parent strain. The cell wall of the parent strain was composed of an outer layer and an inner layer, whereas that of the variants lost the outer layer. After treatment with mitomycin C the parent strain was subjected to lysis and produced bacteriophages with a hexagonal head and a contractible tail, while the nontoxigenic variants did not yield bacteriophages or phage-like structures. There appears to be a close relationship among the toxigenic and sporogenic properties, formation of the outer cell wall layer and lysogeny. 相似文献
4.
Takumi Hiyoshi Hisanori Domon Tomoki Maekawa Kosuke Nagai Hikaru Tamura Naoki Takahashi Daisuke Yonezawa Tomohiro Miyoshi Akihiro Yoshida Koichi Tabeta Yutaka Terao 《Microbiology and immunology》2019,63(3-4):100-110
Aggregatibacter actinomycetemcomitans is considered to be associated with periodontitis. Leukotoxin (LtxA), which destroys leukocytes in humans, is one of this bacterium's major virulence factors. Amounts of neutrophil elastase (NE), which is normally localized in the cytoplasm of neutrophils, are reportedly increased in the saliva of patients with periodontitis. However, the mechanism by which NE is released from human neutrophils and the role of NE in periodontitis is unclear. In the present study, it was hypothesized that LtxA induces NE release from human neutrophils, which subsequently causes the breakdown of periodontal tissues. LtxA‐treatment did not induce significant cytotoxicity against human gingival epithelial cells (HGECs) or human gingival fibroblasts (HGFs). However, it did induce significant cytotoxicity against human neutrophils, leading to NE release. Furthermore, NE and the supernatant from LtxA‐treated human neutrophils induced detachment and death of HGECs and HGFs, these effects being inhibited by administration of an NE inhibitor, sivelestat. The present results suggest that LtxA mediates human neutrophil lysis and induces the subsequent release of NE, which eventually results in detachment and death of HGECs and HGFs. Thus, LtxA‐induced release of NE could cause breakdown of periodontal tissue and thereby exacerbate periodontitis. 相似文献
5.
Kazuhiro Nakaya 《Ichthyological Research》1988,35(2):133-141
Additional specimens of the rareApristurus herklotsi are reported, and the characteristic features of this species are discussed.A. herklotsi is concluded to be a distinct species, having a very long snout, a narrow distance between the nostrils, a long caudal fin,
a short abdomen, numerous teeth on both jaws, and a low number of monospondylous vertebrae.A. herklotsi appears to be mature at about 44 cm in total length. 相似文献
6.
Mark T Uhlik Amy N Abell Bruce D Cuevas Kazuhiro Nakamura Gary L Johnson 《Biochimie et biologie cellulaire》2004,82(6):658-663
Mitogen-activated protein kinase (MAPK) pathways are activated by a plethora of stimuli. The literature is filled with papers describing the activation of different MAPKs by almost any stimulus or insult imaginable to cells. In this review, we use signal transduction wiring diagrams to illustrate putative upstream regulators for the MAPK kinase kinases, MEKK1, 2, and 3. Targeted gene disruption of MEKK1, 2, or 3 defined phenotypes for each MEKK associated with loss of specific MAPK regulation. Genetic analysis of MEKK function clearly defines specific components of the wiring diagram that require MEKK1, 2, or 3 for physiological responses. We propose that signal transduction network wiring diagrams are valuable tools for hypothesis building and filtering physiologically relevant phenotypic responses from less connected protein relations in the regulation of MAPK pathways. 相似文献
7.
Kazuhiro Yamaguchi Klaus D. Jürgens Heinz Bartels Johannes Piiper 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1987,157(1):1-9
Summary To estimate the advantage of the small red blood cells (RBC) of high-altitude camelids for O2 transfer, the kinetics of O2 uptake into and release from the RBC obtained from llama, vicuña and alpaca were investigated at 37°C with a stopped-flow technique. O2 transfer conductance of RBC (G) was estimated from the rate of O2 saturation change and the corresponding O2 pressure difference between medium and hemoglobin. For comparison, O2 kinetics for the RBC of a lowaltitude camelid (dromedary camel) and the pygmy goat were determined and previously measured values for human RBC were used. O2 transfer of RBC was found to be strongly influenced by extracellular diffusion, except with O2 release into dithionite solutions of sufficiently high concentration (>30 mM). TheG values measured in these standard conditions,G
st (in mmol · min–1 · Torr–1 · (ml RBC)–1) were: high-altitude camelids, 0.58 (averaged for llama, alpaca and vicuña since there were no significant interspecific differences); camel 0.42; goat, 0.42; man, 0.39. The differences can in part be attributed to expected effects of the size and shape of the RBC (volume, surface area, mean thickness), as well as to the intracellular O2 diffusivity which depends on the concentration of cellular hemoglobin. The highG
st of RBC of highaltitude camelids may be considered to enhance O2 transfer in lungs and tissues. But the O2 transfer conductance of blood, , equal toG
st multiplied by hematocrit (in mmol · min–1 · Torr–1 · (ml blood)–1), was only slightly higher as compared to other species: 0.20 (llama, alpaca, vicuña), 0.14 (camel), 0.18 (goat), 0.17 (man).Abbreviations
DPG
2,3-diphosphoglycerate
-
G
conductance
-
Hb
hemoglobin
-
RBC
red blood cells
-
percent saturation of hemoglobin 相似文献
8.
Kazuhiro Tanaka 《Archives of microbiology》1990,155(1):18-21
The ability of Desulfovibrio vulgaris strain Marburg (DSM 2119) to oxidize alcohols was surveyed in the presence and absence of hydrogen-scavenging anaerobes, Acetobacterium woodii and Methanospirillum hungatei. In the presence of sulfate, D. vulgaris grew not only on ethanol, 1-propanol, and 1-butanol, but also on isobutanol, 1-pentanol, ethyleneglycol, and 1,3-propanediol. Metabolism of these alcohols was simple oxidation to the corresponding acids, except with the last two substrates: ethyleneglycol was oxidized to glycolate plus acetate, 1,3-propanediol to 3-hydroxypropionate plus acetate. Experimental evidence was obtained, suggesting that 2-methoxyethanol was not utilized by all the cells of strain marburg, but by a spontaneous mutant. 2-Methoxyethanol was oxidized to methoxyacetate by the mutant. Co-culture of strain Marburg plus A. woodii grew on ethanol, 1-propanol, 1-butanol, and 1,3-propanediol in the absence of sulfate. Co-culture of strain Marburg plus M. hungatei grew on ethanol, 1-propanol, and 1-butanol, but not on ethyleneglycol and 1,3-propanediol, Co-culture of the mutant plus A. woodii or M. hungatei did not grow on 2-methoxyethanol. 相似文献
9.
Masanori Ito Kazuhiro Yoshida Eikai Kyo Ayse Ayhan Hirofumi Nakayama Wataru Yasui Hisao Ito Eiichi Tahara 《Virchows Archiv. B, Cell pathology including molecular pathology》1990,59(1):173-178
We have examined the expression of mRNAs for epidermal growth factor (EGF), transforming growth factor-alpha (TGF-α), EGF
receptor (EGFR), PDGF-A chain (PDGFA), PDGF-B chain (PDGFB) and PDGF receptor (PDGFR) genes in seven human colorectal carcinoma
cell lines and 18 human colorectal carcinomas.
In surgically resected specimens of the 18 colorectal tumors, TGF-α, EGFR, PDGFA, PDGFB and PDGFR mRNAs were detected at various
levels in 15 (83%), 9 (50%), 18 (100%), 8 (44%) and 12 (67%), respectively. They were also detected in normal tissues. Interestingly,
EGF mRNA was detected in only five (28%) of the tumors, but not in normal mucosa. Expression of EGF was also confirmed immunohistochemically
in tumor cells. Of the five tumors expressing EGF, four expressed EGFR mRNA and showed a tendency to invade veins and lymphatics.
All the colorectal carcinoma cell lines expressed TGF-α mRNA, and five cell lines expressed EGFR mRNA simultaneously. Production
of TGF-α protein by DLD-1 and CoLo320DM cells was confirmed by TGF-α specific monoclonal antibody binding assay. The spontaneous3H-thymidine uptake by DLD-1 was suppressed by an anti-TGF-α monoclonal antibody. PDGFA and PDGFB mRNA were also expressed
in four cell lines, but PDGFR and EGF mRNA was not detected. These results suggest that human colorectal carcinomas express
multi-loops of growth factors and that TGF-α produced by tumor cells functions as an autocrine growth factor in human colonic
carcinoma. 相似文献
10.