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1.
Takatoshi Murata Tsutomu Sato Takeshi Kamoda Hiromitsu Moriyama Yasuo Kumazawa Nobuhiro Hanada 《Experimental cell research》2014
Hydrogen sulfide (H2S) is a novel gasotransmitter that plays multiple biological roles in various body systems. In addition to its endogenous production, H2S is produced by bacteria colonizing digestive organs, including the oral cavity. H2S was previously shown to enhance pro-apoptotic effects in cancer cell lines, although the mechanisms involved remain unclear. To properly assess the anti-cancer effects of H2S, however, investigations of apoptotic effects in normal cells are also necessary. The aims of this study were (1) to compare the susceptibility to H2S-induced apoptosis between the oral cancer cell line Ca9-22 and oral keratinocytes that were derived from healthy gingiva, and (2) to identify candidate genes involved in the induction of apoptosis by H2S. The susceptibility to H2S-induced apoptosis in Ca9-22 cells was significantly higher than that in keratinocytes. H2S exposure in Ca9-22 cells, but not keratinocytes, enhanced the expression of pleckstrin homology-like domain, family A, member 1 (PHLDA1), which was identified through a differential display method. In addition, PHLDA1 expression increased during actinomycin D-induced apoptosis in Ca9-22 cells. Knockdown of PHLDA1 expression by small interfering RNA in Ca9-22 cells led to expression of active caspase 3, thus indicating apoptosis induction. The tongue cancer cell line SCC-25, which expresses PHLDA1 at a high level, showed similar effects. Our data indicate that H2S is an anti-cancer compound that may contribute to the low incidence of oral cancer. Furthermore, we demonstrated the role of PHLDA1 as an apoptosis suppressor. 相似文献
2.
Intra‐trophic isotopic discrimination of 15N/14N for amino acids in autotrophs: Implications for nitrogen dynamics in ecological studies 下载免费PDF全文
Yuko Takizawa Prarthana S. Dharampal Shawn A. Steffan Yoshinori Takano Naohiko Ohkouchi Yoshito Chikaraishi 《Ecology and evolution》2017,7(9):2916-2924
The differential discrimination of nitrogen isotopes (15N/14N) within amino acids in consumers and their diets has been routinely used to estimate organismal tropic position (TP). Analogous isotopic discrimination can occur within plants, particularly in organs lacking chloroplasts. Such discrimination likely arises from the catabolic deamination of amino acids, resulting in a numerical elevation of estimated TP, within newly synthesized biomass. To investigate this phenomenon, we examined the 15N/14N of amino acids (δ15NAA) in spring leaves and flowers from eight deciduous and two annual plants. These plants were classified on the basis of their time of bloom, plants that bloomed when their leaves were absent (Type I) versus plants that bloomed while leaves were already present (Type II). Based on the δ15NAA values from leaves, both plant types occupied comparable and ecologically realistic mean TPs (=1.0 ± 0.1, mean ± 1σ). However, the estimated TPs of flowers varied significantly (Type I: 2.2 ± 0.2; Type II: 1.0 ± 0.1). We hypothesize that these results can be interpreted by the following sequence of events: (1) Type I floral biomass is synthesized in absence of active photosynthesis; (2) the catabolic deamination of amino acids in particular, leaves behind 15N in the residual pool of amino acids; and (3) the incorporation of these 15N‐enriched amino acids within the biomass of Type I flowers results in the numerical elevation of the TPs. In contrast, the actively photosynthesizing Type II leaves energetically sustain the synthesis of Type II flower biomass, precluding any reliance on catabolic deamination of amino acids. Amino acids within Type II flowers are therefore isotopically comparable to the Type II leaves. These findings demonstrate the idiosyncratic nature of the δ15NAA values within autotrophic organs and have implications for interpreting trophic hierarchies using primary producers and their consumers. 相似文献
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4.
Mutations in the profilin 1 (PFN1) gene have been identified as a cause of familial amyotrophic lateral sclerosis (ALS), and neuropathological studies indicate that TDP-43 is accumulated in brains of patients with PFN1 mutation. Here, we investigated the role of PFN1 mutations in the formation of prion-like abnormal TDP-43. Expression of PFN1 with pathogenic mutations resulted in the formation of cytoplasmic aggregates positive for p62 and ubiquitin, and these aggregates sequestered endogenous TDP-43. TDP-43 accumulation was facilitated in the presence of proteasome or lysosome inhibitor. Co-expression of mutant PFN1 and TDP-43 increased the levels of detergent-insoluble and phosphorylated TDP-43, and this increase required the C-terminal region of TDP-43. Moreover, detergent-insoluble fractions prepared from cells expressing ALS-linked mutant PFN1 induced seed-dependent accumulation of TDP-43. These findings indicate that expression of PFN1 mutants induces accumulation of TDP-43, and promotes conversion of normal TDP-43 into an abnormal form. These results provide new insight into the mechanisms of TDP-43 proteinopathies and other diseases associated with amyloid-like protein deposition. 相似文献
5.
Naoya YASHIRO Yoshimi HIROSE Jeffrey Y. HONDA Yoshinori TAKEUCHI Toshihisa YASHIRO 《Entomological Science》2012,15(2):189-196
A new species of Trichogramma that parasitizes Sialis melania eggs is described as Trichogramma tajimaense Yashiro, Hirose and Honda, sp. nov. from Japan. Its phylogenetic position is based on a DNA‐based analysis, and data regarding its male wing polymorphism are also presented. The view that T. tajimaense is closely related to T. semblidis, another parasitoid of Sialis eggs, is supported by the results of a phylogenetic analysis, as well as by the biological and morphological similarities between both species. Trichogramma tajimaense is also similar in male wing polymorphism to T. kurosuae, a gregarious egg parasitoid of the lepidopteran Ivela auripes, as both Trichogramma species exhibit male wing trimorphism (fully alate, brachypterous and apterous forms) in contrast to the male wing dimorphism (fully alate and apterous forms) of T. semblidis. However, no phylogenetic analysis reveals a close relationship between T. tajimaense and T. kurosuae, and a difference exists between these two species in the mean percentage of flightless (brachypterous and apterous) males that emerge from a host egg mass; 96% of T. tajimaense males are incapable of flight, whereas about 50% of T. kurosuae males are flightless. Because all or almost all males of T. semblidis parasitizing Sialis eggs are apterous, T. tajimaense is more similar to T. semblidis than to T. kurosuae in the proportion of flightless males. In addition, male wing polymorphisms of Trichogramma in relation to mating systems could also show a similarity between T. tajimaense and T. semblidis when considering both species as quasi‐gregarious parasitoids of Sialis eggs. 相似文献
6.
Junko Kitagawa Takeshi Nakagawa Masaaki Okuda Masaharu Fukuoka Yoshinori Yasuda 《Economic botany》2008,62(4):594-603
Correcting Misperceptions about the History of
Castanea
Stands in
Satoyama
in Japan. Mistaken ideas about the naturalness of past and present landscapes are widespread in diverse cultures and in the scientific
literature, and many of these ideas are only now being seriously challenged by current research (e.g., Erickson 2006; Fairhead and Leach 1996; Hall 1998; Ramankutty and Foley 1999; Willis et al. 2004). For example, the chestnut, Castanea crenata, has long been an important tree in Japanese culture, which has been cultivated, among other things, for its much loved edible
nut and its valuable timber. Today, the widely-held view in Japan, which also appears in the scholarly and popular literature,
is that in the past Castanea stands covered a large area throughout Japan, and these stands only disappeared because of economic development, especially
in association with railway construction. Otaru, Hokkaido, is one of the places where people believe Castanea stands covered a large area and were deforested only recently. Local people in Otaru believe that the stand in Temiya Park
has existed since the Jomon Period. For a more accurate historical perspective on Japanese forestation, we have performed
pollen analysis to clarify the timing of the introduction of the Castanea tree into Otaru region and to reveal the history of this specific Castanea stand in Temiya Park. The results indicate that Castanea was first found in Otaru region 7100 B.P., but that it was not cultivated extensively until recently. Based on our study,
and on data from this area dating to the late 19th century, we concluded instead that the Castanea stand we studied in Temiya Park, Otaru, was established after the mid-20th century. We believe the results of this study
are applicable to Castanea stands in other parts of Japan as well. 相似文献
7.
Synchronously growing cells of nitrogen-fixing Synechococcus sp. Miami BG 043511 were harvested periodically and the capability for hydrogen photoproduction in closed vessels was measured under hydrogen production conditions. The capability for hydrogen photoproduction in cells was correlated with that of cellular carbohydrate content. Cells with a high carbohydrate content exhibited a high capacity for hydrogen production and those with low carbohydrate content exhibited low capacity for hydrogen production. Nitrogenase activity at the onset of incubation did not coincide with a capability for the cells to produce hydrogen during the subsequent incubation period. Interestingly, when cells with a high capacity for hydrogen photoaccumulation were incubated, alternate periods of hydrogen and oxygen accumulation were observed at 12 hour intervals. About 0.5 ml of hydrogen per ml of cell suspension was accumulated in flasks during the initial 12-h incubation period. These observations indicate that the use of synchronous culture can be one of the ways of provide materials suitable not only for basic studies but also for applied aspects of hydrogen photoproduction. 相似文献
8.
We attempted to identify the genes involved in cellularsenescence, telomere maintenance and telomerase regulationthrough subtractive screening of cDNA libraries prepared froma human lung adenocarcinoma cell line A549 and its sublinesnamed A5DC7, CK and AST-9. Cell phenotypes of A5DC7, CK andAST-9 are normal cell-like, cancer cell-like and intermediate,respectively. These cell lines have different phenotypes interms of telomerase activity and telomere maintenance, andthus are thought to be useful for identifying the genesinvolved in cellular senescence and telomerase regulation. In this study, we identified 86 independent cDNA clones bysubtractive screening. Among these cDNA clones, subtractingA5DC7 cDNAs from A549 cDNAs and CK cDNAs gave 7 and 3 cDNAclones which highly and specifically expressed in tester celllines. Genes corresponding to these 10 cDNA clones mightparticipate in maintaining cancer-cell phenotypes. As aresult of database searching, each four of A549 specific cDNAclones are found to correspond to known cDNAs. Each two ofA549 specific and two of CK specific cDNA clones have highhomology to independent ESTs. Sequences having homology toeach one of A549 specific and one of CK specific cDNA cloneshave not been deposited in the Genbank database, indicatingthat these two cDNA clones are part of novel genes. Weanticipate that their involvement in telomerase regulationand/or senescence program can be clarified by functionalanalysis using each full-length cDNA. 相似文献
9.
Pitavastatin up-regulates the induction of iNOS through enhanced stabilization of its mRNA in pro-inflammatory cytokine-stimulated hepatocytes. 总被引:1,自引:0,他引:1
10.
Intramembrane metalloproteases are nearly ubiquitous in living organisms and they function in diverse processes ranging from cholesterol homeostasis and the unfolded protein response in humans to sporulation, stress responses, and virulence of bacteria. Understanding how these enzymes function in membranes is a challenge of fundamental interest with potential applications if modulators can be devised. Progress is described toward a mechanistic understanding, based primarily on molecular genetic and biochemical studies of human S2P and bacterial SpoIVFB and RseP, and on the structure of the membrane domain of an archaeal enzyme. Conserved features of the enzymes appear to include transmembrane helices and loops around the active site zinc ion, which may be near the membrane surface. Extramembrane domains such as PDZ (PSD-95, DLG, ZO-1) or CBS (cystathionine-β-synthase) domains govern substrate access to the active site, but several different mechanisms of access and cleavage site selection can be envisioned, which might differ depending on the substrate and the enzyme. More work is needed to distinguish between these mechanisms, both for enzymes that have been relatively well-studied, and for enzymes lacking PDZ and CBS domains, which have not been studied. This article is part of a Special Issue entitled: Intramembrane Proteases. 相似文献