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41.
Proteome analysis of programmed cell death and defense signaling using the rice lesion mimic mutant cdr2 总被引:7,自引:0,他引:7
Tsunezuka H Fujiwara M Kawasaki T Shimamoto K 《Molecular plant-microbe interactions : MPMI》2005,18(1):52-59
We have previously identified three lesion-mimic mutants, cell death and resistance (cdr), in rice. These mutants induce a series of defense responses, including expression of defense-related genes and high accumulation of phytoalexins, indicating that the cdr mutants are useful materials to study programmed cell death and defense signaling in rice. Here, we carried out a proteome analysis of the cdr2 mutant. Total proteins prepared from the wild type and the cdr2 mutant at three different stages of lesion formation were compared using two-dimensional electrophoresis. We found a total of 37 proteins that were differentially expressed between cdr2 and wild type. Among them, 28 spots were up-regulated and nine were down-regulated in the cdr2 mutant. All the protein spots were identified by mass spectrometric analysis. These differentially regulated proteins included defense-related proteins. In addition, 27 proteins were classified as metabolic enzymes, suggesting that the programmed cell death that occurs in the cdr2 mutant is associated with active metabolic changes. Our study shows that proteome analysis is a useful approach to study programmed cell death and defense signaling in plants. 相似文献
42.
Growth patterns and substrate requirements of naturally occurring obligate oligotrophs 总被引:1,自引:0,他引:1
Eighteen strains of obligately oligotrophic bacteria that grow in a medium containing 1 mg of organic carbon per liter and do not grow in a rich medium (5 g/liter of nutrient) were isolated as dominant organisms from the oligotrophic water of Lake Biwa. The growth properties of these, especially of five strains, were examined. The maximum cell yield ranged from 8.5×104/ml to 2.3×106/ml, and their doubling times ranged from 6.6/h to 11.8/h in LT10–4 medium (0.5 mg trypticase and 0.05 mg yeast extract in 1 liter of filtered and aged lake water). They also showed good growth in lake water medium without adding nutrients. The optimum concentrations for their growth were 5 mg/1, 5–50 mg/1, 50 mg/1, or 500 mg/1, depending on the strains. They utilized glutamate, glycine, serine, and glycolate, but not acetate, proline, or leucine. Several properties were examined. Their growth properties were very different from those of oligotrophs or oligocarbophiles isolated by other researchers. 相似文献
43.
Stress responses in Salix gracilistyla cuttings subjected to repetitive alternate flooding and drought 总被引:2,自引:0,他引:2
To determine the tolerance of Salix gracilistyla to repetitive alternate flooding and drought, we measured leaf stomatal conductance, pre-dawn water potential, osmotic adjustment,
and biomass production under greenhouse conditions. We used a control and nine crossed treatments (F1-D1–F3-D3) in which we
combined 1-, 2-, or 3-week floodings (F) and droughts (D). Leaf stomatal conductance was lowest in 3 weeks of flooding or
drought when the preceding event (flood or drought) was also of a 3-week duration. Leaf pre-dawn water potential was reduced
in 3 weeks of drought when preceded by 2 or 3 weeks of flooding. Cuttings had slight osmotic adjustments in repetitions of
long floodings and droughts. During longer durations of drought in crossed experiments, plants had low root and shoot mass,
few hypertrophic lenticels, and reduced leaf mass; when flooding duration increased in crossed experiments, root mass was
reduced, there were more hypertrophic lenticels, and the leaf area was reduced. Cuttings achieved stress tolerance by inhibition
of transpiration, osmotic adjustment, reduction of transpiration area, and development of hypertrophic lenticels. Stress tolerance
was weak when repetitive 2- or 3-week floodings were combined with 3-week droughts. The duration of flooding and drought periods
under which S. gracilistyla achieves stress tolerance may be critical in determining distributions along riverbanks. 相似文献
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Kerstin Törner Takashi Nakanishi Tomoaki Matsuura Yasuhiko Kato Hajime Watanabe 《Molecular genetics and genomics : MGG》2014,289(4):707-715
The water flea Daphnia is a new model organism for ecological, evolutionary, and toxicological genomics. Detailed functional analysis of genes newly discovered through genomic approaches often requires overexpression of the identified protein. In the present study, we report the microinjection of in vitro-synthesized RNAs into the eggs as a method for overexpressing ubiquitous proteins in Daphnia magna. We injected a 1.3-kb mRNA that coded for the red fluorescent protein (DsRed2) flanked by UTRs from the ubiquitously expressed elongation factor 1α-1 (EF1α-1) into D. magna embryos. DsRed2 fluorescence in the embryos was measured 24 h after microinjection. Unexpectedly, the reporter RNA containing the 522-bp full-length EF1α-1 3′ UTR failed to induce fluorescence. To assess reporter expression, the length of the 3′ UTR that potentially contained negative regulatory elements of protein expression, including AU-rich regions and Musashi binding elements, was serially reduced from the 3′ end. Assessing all injected RNA alternatives, mRNA containing the first 60 bp of the 3′ UTR gave rise to the highest fluorescence, 14 times the Daphnia auto-fluorescence. In contrast, mRNA lacking the entire 3′ UTR hardly induced any change in fluorescence intensity. This is the first evaluation of UTRs of mRNAs delivered into Daphnia embryos by microinjection for overexpressing proteins. The mRNA with truncated 3′ UTRs of Daphnia EF1α-1 will be useful not only for gain-of-function analyses but also for labeling proteins and organelles with fluorescent proteins in Daphnia. 相似文献
46.
A novel polymer blend system consisting of poly(l-lactide) (PLLA) and a thermotropic liquid crystalline polymer (LCP: an aromatic polyester comprising poly(4-hydroxybenzoate) sequences) was investigated in the presence and absence of a polycabodiimide (PCD). Scanning electron micrographs of the injection-molded polymer blends revealed the formation of fibrous structure of LCP in the PLLA matrix, supporting the efficient toughening. In particular, the LCP fibrils became semimicrometer in diameter in the presence of PCD with which both PLLA and LCP had reacted during the melt blending to form their block and graft copolymers working as compatibilizer. The blend specimens containing LCP in 20-30 wt % were found to hold high dynamic storage-moduli (E') at high temperature. In addition, the E' value of the specimens containing 30 wt % of LCP reached 10.7 GPa at room temperature, being significantly higher than that of PLLA. 相似文献
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48.
Protein phosphatases are critical for the regulation of many cellular processes. Null mutants of 21 putative protein phosphatases of Candida albicans were constructed by consecutive allele replacement using the URA3 and ARG4 marker genes. A simple silkworm model of C. albicans infection was used to screen the panel of mutants. Four null mutant (cmp1Δ, yvh1Δ, sit4Δ, and ptc1Δ) strains showed attenuated virulence in the silkworm model relative to that of control and parental strains. Three of the mutants, the cmp1Δ, yvh1Δ, and sit4Δ mutants, had previously been identified as affecting virulence in a conventional mouse model, indicating the validity of the silkworm model screen. Disruption of the putative protein phosphatase gene PTC1 of C. albicans, which has 52% identity to the Saccharomyces cerevisiae type 2C protein phosphatase PTC1, significantly reduced virulence in the silkworm model. The mutant was also avirulent in a mouse model of disseminated candidiasis. Reintroducing either of the C. albicans PTC1 alleles into the disruptant strain, using a cassette containing either allele under the control of a constitutive ACT1 promoter, restored virulence in both infection models. Characterization of ptc1Δ revealed other phenotypic traits, including reduced hyphal growth in vitro and in vivo, and reduced extracellular proteolytic activity. We conclude that PTC1 may contribute to pathogenicity in C. albicans. 相似文献
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