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71.
Jun-ichi Tsuboi Kentaro Morita Yusuke Koseki Shinsuke Endo Genki Sahashi Daisuke Kishi Takeshi Kikko Daisuke Ishizaki Masanori Nunokawa Yoichiro Kanno 《Oikos》2020,129(6):924-937
Animal populations are spatially structured in heterogeneous landscapes, in which local patches with differing vital rates are connected by dispersal of individuals to varying degrees. Although there is evidence that vital rates differ among local populations, much less is understood about how vital rates covary among local patches in spatially heterogeneous landscapes. In this study, we conducted a nine-year annual mark–recapture survey to characterize spatial covariation of survival and growth for two Japanese native salmonids, white-spotted charr Salvelinus leucomaenis japonicus and red-spotted masu salmon Oncorhynchus masou ishikawae, in a headwater stream network composed of distinctly different tributary and mainstem habitats. Spatial structure of survival and growth differed by species and age class, but results provided support for negative covariation between vital rates, where survival was higher in the tributary habitat but growth was higher in the mainstem habitat. Thus, neither habitat was apparently more important than the other, and local habitats with complementary vital rates may make this spatially structured population less vulnerable to environmental change (i.e. portfolio effect). Despite the spatial structure of vital rates and possibilities that fish can exploit spatially distributed resources, movement of fish was limited due partly to a series of low-head dams that prevented upstream movement of fish in the study area. This study shows that spatial structure of vital rates can be complex and depend on species and age class, and this knowledge is likely paramount to elucidating dynamics of spatially structured populations. 相似文献
72.
Daisuke Takagi Atsuko Miyagi Youshi Tazoe Mao Suganami Maki Kawai-Yamada Akihiro Ueda Yuji Suzuki Ko Noguchi Naoki Hirotsu Amane Makino 《Plant, cell & environment》2020,43(9):2033-2053
Phosphorus (P) is an essential mineral nutrient for plants. Nevertheless, excessive P accumulation in leaf mesophyll cells causes necrotic symptoms in land plants; this phenomenon is termed P toxicity. However, the detailed mechanisms underlying P toxicity in plants have not yet been elucidated. This study aimed to investigate the molecular mechanism of P toxicity in rice. We found that under excessive inorganic P (Pi) application, Rubisco activation decreased and photosynthesis was inhibited, leading to lipid peroxidation. Although the defence systems against reactive oxygen species accumulation were activated under excessive Pi application conditions, the Cu/Zn-type superoxide dismutase activities were inhibited. A metabolic analysis revealed that excessive Pi application led to an increase in the cytosolic sugar phosphate concentration and the activation of phytic acid synthesis. These conditions induced mRNA expression of genes that are activated under metal-deficient conditions, although metals did accumulate. These results suggest that P toxicity is triggered by the attenuation of both photosynthesis and metal availability within cells mediated by phytic acid accumulation. Here, we discuss the whole phenomenon of P toxicity, beginning from the accumulation of Pi within cells to death in land plants. 相似文献
73.
74.
Ryotaro Nishi Wataru Sakai Daisuke Tone Fumio Hanaoka Kaoru Sugasawa 《Nucleic acids research》2013,41(14):6917-6929
Centrin-2 is an evolutionarily conserved, calmodulin-related protein, which is involved in multiple cellular functions including centrosome regulation and nucleotide excision repair (NER) of DNA. Particularly to exert the latter function, complex formation with the XPC protein, the pivotal NER damage recognition factor, is crucial. Here, we show that the C-terminal half of centrin-2, containing two calcium-binding EF-hand motifs, is necessary and sufficient for both its localization to the centrosome and interaction with XPC. In XPC-deficient cells, nuclear localization of overexpressed centrin-2 largely depends on co-overexpression of XPC, and mutational analyses of the C-terminal domain suggest that XPC and the major binding partner in the centrosome share a common binding surface on the centrin-2 molecule. On the other hand, the N-terminal domain of centrin-2 also contains two EF-hand motifs but shows only low-binding affinity for calcium ions. Although the N-terminal domain is dispensable for enhancement of the DNA damage recognition activity of XPC, it contributes to augmenting rather weak physical interaction between XPC and XPA, another key factor involved in NER. These results suggest that centrin-2 may have evolved to bridge two protein factors, one with high affinity and the other with low affinity, thereby allowing delicate regulation of various biological processes. 相似文献
75.
Ryu Osaka Masayoshi Watada Daisuke Kageyama Masashi Nomura 《Symbiosis (Philadelphia, Pa.)》2013,60(2):79-84
Some members of the genus Spiroplasma are vertically transmitted endosymbionts of insects. Among them, Spiroplasma sp. Dhd, a member of the Spiroplasma poulsonii clade, is highly prevalent among worldwide populations of Drosophila hydei. Here we found that 53 out of 3,763 wild-caught D. hydei (1.4 %) were ectoparasitized by the mite that belong to the genus Macrocheles. Many of the ectoparasitized flies (79 %) had a single mite, but some flies had up to five mites. Among 59 mites subjected to Spiroplasma-specific PCR, 15 individuals were found to be positive. Infection status of Spiroplasma in flies and the associated mites were incongruent. Partial nucleotide sequences of the Spiroplasma P58 gene suggest that some of the mites are infected with a Spiroplasma, which is identical or closely related to Spiroplasma sp. Dhd. This finding provides a potential route of horizontal Spiroplasma transmission between D. hydei individuals in natural populations. In addition, a Spiroplasma strain that does not form a monophyletic group with S. poulsonii was also found from a mite individual. 相似文献
76.
Atsuyoshi Nishina Hirokazu Kimura Hiroyuki Tsukagoshi Kunihisa Kozawa Mamoru Koketsu Masayuki Ninomiya Daisuke Sato Yutaro Obara Shoei Furukawa 《Neurochemical research》2013,38(11):2397-2407
The cellular effects of eleven compounds including chalcone glycosides isolated from Brassica rapa L. ‘hidabeni’ and their synthetic derivatives were studied in rat pheochromocytoma PC12 cells. Of the compounds tested, 4′-O-β-d-glucopyranosyl-3′,4-dimethoxychalcone (A2) significantly increased the levels of the phosphorylated forms of extracellular signal-regulated kinases 1/2 (ERK 1/2), p38 mitogen-activated protein kinase (p38MAPK), and stress-activated protein kinases/Jun amino-terminal kinases (JNK/SAPK), but it did not affect Akt. Nerve growth factor (NGF), a well-known neurotrophic factor, increased the levels of phosphorylated ERK1/2, JNK/SAPK, and Akt but not p38MAPK, which may mediate marked neurite outgrowth. Signals evoked by A2 shared common characteristics with those induced by NGF; therefore, we evaluated the neuritogenic activity of A2 and found it induced only weak neurite outgrowth. However, this effect was enhanced by pre-treatment with a p38MAPK inhibitor, suggesting that the phosphorylation of p38MAPK down-regulated neurite outgrowth. From the results of this study, it was found that A2 in combination with a p38MAPK inhibitor can induce NGF-like effects. Hence, a combination of chalcone glycosides containing A2 and a p38MAPK inhibitor increases the likelihood that chalcone glycosides could be put to practical use in the form of drugs or alternative medicines to maintain neural health. 相似文献
77.
Rika Kamei Mana Miyakoda Takahiko Tamura Daisuke Kimura Kiri Honma Kazumi Kimura Katsuyuki Yui 《Microbiology and immunology》2013,57(3):213-223
78.
Rice Resistance to Planthoppers and Leafhoppers 总被引:3,自引:0,他引:3
For over 50 years, host-plant resistance has been regarded as an efficient method to reduce yield losses to rice caused by delphacid and cicadelid hoppers. Already a number of resistant rice varieties have been developed and deployed throughout Asia. To date, over 70 hopper resistance genes have been identified in rice; however, less than 10 genes have been deliberately introduced to commercial rice varieties. Currently, due to recent brown planthopper (Nilaparvata lugens [Stål]) and whitebacked planthopper (Sogatella furcifera [Horvath]) outbreaks occurring at an unprecedented scale, researchers are working toward a second generation of resistant varieties using newly identified gene loci and applying new molecular breeding methods. This paper reviews advances in the identification of resistance genes and QTLs against hoppers in rice. It collates all published information on resistance loci and QTLs against the major rice planthoppers and leafhoppers and presents information on gene locations, genetic markers, differential varieties, and wild rice species as sources of resistance. The review indicates that, whereas progress in the identification of genes has been rapid, considerable tidying of the information is required, especially regarding gene nomenclature and resistance spectra. Furthermore, sound information on gene functioning is almost completely lacking. However, hopper responses to resistance mechanisms are likely to be similar because a single phenotyping technique has been applied by most national and international breeding programs during germplasm screening. The review classifies genes occurring at two chromosome regions associated with several identified resistance loci and highlights these (Chr4S: BphR-R and Chr12L: BphR-R) as general stress response regions. The review calls for a greater diversity of phenotyping methods to enhance the durability of resistant varieties developed using marker-aided selection and emphasizes a need to anticipate the development of virulent hopper populations in response to the field deployment of genes. 相似文献
79.
OsTZF1, a CCCH-Tandem Zinc Finger Protein,Confers Delayed Senescence and Stress Tolerance in Rice by Regulating Stress-Related Genes 总被引:1,自引:0,他引:1
80.
Hiroaki Tanaka Ken-ichi Akagi Chitose Oneyama Masakazu Tanaka Yuichi Sasaki Takashi Kanou Young-Ho Lee Daisuke Yokogawa Marc-Werner Dobenecker Atsushi Nakagawa Masato Okada Takahisa Ikegami 《The Journal of biological chemistry》2013,288(21):15240-15254
Proteins with Src homology 2 (SH2) domains play major roles in tyrosine kinase signaling. Structures of many SH2 domains have been studied, and the regions involved in their interactions with ligands have been elucidated. However, these analyses have been performed using short peptides consisting of phosphotyrosine followed by a few amino acids, which are described as the canonical recognition sites. Here, we report the solution structure of the SH2 domain of C-terminal Src kinase (Csk) in complex with a longer phosphopeptide from the Csk-binding protein (Cbp). This structure, together with biochemical experiments, revealed the existence of a novel binding region in addition to the canonical phosphotyrosine 314-binding site of Cbp. Mutational analysis of this second region in cells showed that both canonical and novel binding sites are required for tumor suppression through the Cbp-Csk interaction. Furthermore, the data indicate an allosteric connection between Cbp binding and Csk activation that arises from residues in the βB/βC loop of the SH2 domain. 相似文献