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1.
Takahashi M Teranishi M Ishida H Kawasaki J Takeuchi A Yamaya T Watanabe M Makino A Hidema J 《The Plant journal : for cell and molecular biology》2011,68(3):433-442
Plants use sunlight as energy for photosynthesis; however, plant DNA is exposed to the harmful effects of ultraviolet‐B (UV‐B) radiation (280–320 nm) in the process. UV‐B radiation damages nuclear, chloroplast and mitochondrial DNA by the formation of cyclobutane pyrimidine dimers (CPDs), which are the primary UV‐B‐induced DNA lesions, and are a principal cause of UV‐B‐induced growth inhibition in plants. Repair of CPDs is therefore essential for plant survival while exposed to UV‐B‐containing sunlight. Nuclear repair of the UV‐B‐induced CPDs involves the photoreversal of CPDs, photoreactivation, which is mediated by CPD photolyase that monomerizes the CPDs in DNA by using the energy of near‐UV and visible light (300–500 nm). To date, the CPD repair processes in plant chloroplasts and mitochondria remain poorly understood. Here, we report the photoreactivation of CPDs in chloroplast and mitochondrial DNA in rice. Biochemical and subcellular localization analyses using rice strains with different levels of CPD photolyase activity and transgenic rice strains showed that full‐length CPD photolyase is encoded by a single gene, not a splice variant, and is expressed and targeted not only to nuclei but also to chloroplasts and mitochondria. The results indicate that rice may have evolved a CPD photolyase that functions in chloroplasts, mitochondria and nuclei, and that contains DNA to protect cells from the harmful effects of UV‐B radiation. 相似文献
2.
In this work, an over-expressed cyclobutane pyrimidine dimer (CPD) photolyase of Synechococcus sp. PCC 7942 was used to investigate UV-C (ultraviolet irradiation of C-region) influence on photoreactivation. In vivo photoreactivation experiments indicated that the survival rate decreased from 100 to 2.6% when the UV-C flux was increased
from 1.1 to 68.5 μW/cm2. It seemed that the photolyase was easily inactivated at UV-C intensities ≥25.5 μW/cm2. Spectrometric analysis indicated that tertiary structure of the photolyase changed evidently when the UV-C fluxes were ≥25.5
μW/cm2, while the secondary structure was almost unchanged even at 170 μW/cm2. Band shift assay indicated that catalytic activity of the photolyase was impaired at fluxes ≥25.5 μW/cm2, but no significant influence on DNA-binding activity was observed. These results suggest that photoreactivation is efficient
at UV-C fluxes ≤25.5 μW/cm2, but would be impaired by intense UV-C irradiation due to structure changes of the photolyase.
Published in Russian in Biokhimiya, 2007, Vol. 72, No. 5, pp. 668–673. 相似文献
3.
4.
Phytochelatins (PCs) play an important role in heavy-metal homeostasis and detoxification. However, we previously reported
that the overexpression of PC synthase inArabidopsis does not lead to increased tolerance of cadmium but, rather, plants show higher Cd sensitivity. Here, we compared the maximum
capacity for non-protein thiol (NPT) production at various concentrations of Cd in order to estimate PC synthesis indirectly
for both transgenic (pcs9) and wild-type plants. The pcs9 line produced the highest level of NPT when treated with 200 p.M
Cd for 3 d. In comparison, the maximum productivity by the wild type was in response to 500 μM Cd. Nevertheless, the absolute
amounts of NPT produced did not differ significantly between those two genotypes. Furthermore, exogenous application of 1
mM GSH did not dramatically change the capacity for either pcs9 or wild-type plants. These results suggest that Cd hypersensitivity
in the transgenic pcs9 may not be caused by supraoptimal intracellular concentrations of PC, but may, instead, be due to overexpressed
PC synthase itself because that enzyme can bind metals. This action, therefore, may lead to some unknown disruption in cellular
metal homeostasis under Cd stress. 相似文献
5.
Indeok Hwang Dilli Prasad Paudyal Seong-Ki Kim Hyeonsook Cheong 《Biotechnology and Bioprocess Engineering》2007,12(2):157-164
Inhibitors are very important in the study of hormone function. Brasinazole (Brz) is a specific inhibitor of brassinosteroids
(BRs) biosynthesis. To expand our knowledge of the molecular mechanisms of plant steroid signaling, we performed genetic screening
using medium containing Brz under dark conditions. Mutants insensitive to Brz developlonger hypocotyls than their wild type
counterparts. We isolatedabz453 as a Brz insensitive mutant. TAIL-PCR and the segregation ratio of T2 plants indicated a single T-DNA insertion at the 24-Sterol
C-methyltransferase (SMT2) gene in theabz453 mutant. Recapitulation for putative FCP serine phosphatase (FSP), the gene neighboringSMT2, indicated no significant phenotypes, but theSMT2 anti-sense (SMT2-AS) line developed longer hypocotyls than the wild type in medium containing Brz. Additionally, theSMT2-AS line displayed similar phenotypes to theabz453 line in soil including enhanced growth and smaller silique. Theabz453 andSMT2-AS mutants showed phenotypes similar to those of wild type in medium containing benzylaminopurine, pacrobutrazol and ACC (precursor
for ethylene) under dark conditions. However, when brassinolide (BL) dose response was observed, theabz453 andSMT2-AS lines showed higher sensitivity than wild type. Theabz453/det2 andabz453/bri1-119 double mutants showed enhanced growth compared to thedet2 andbri1-119 line under both dark and light conditions. Specially, in dark conditions double mutants displayed nearly 2- and 1.5-fold
longer hypocotyls thandet2 andbri1-119 plants. Brz insensitivity to theSMT2 knock-out mutant and phenotypes of double mutants indicate that not only do BRI1 and DET2 influence the BRs response, as
evidenced by hypocotyl elongation, but another sterol derived signals may also be affected in mutants, suggesting that another
pathway is involved in hypocotyl elongation due to SMT2. 相似文献
6.
Takeuchi Y Inoue T Takemura K Hada M Takahashi S Ioki M Nakajima N Kondo N 《Journal of plant research》2007,120(3):365-374
7.
Gaye Öngen Gaye Güngör Bahar Kanberoglu 《World journal of microbiology & biotechnology》2007,23(4):519-524
Aspergillus section Nigri strains Aspergillus aculeatus Ege-K 258, A.
foeditus var. pallidus Ege-K156, A. niger Ege-K 4 and A. tubingensis Ege-K 265 were used to treat olive mill wastewater (OMW) in an investigation aimed at exploring their dephenolisation and
decolourisation ability and, consequently, the economic feasibility of using any or all of these strains in a pre-treatment
step in the processing of OMW. Of these strains A. tubingensis Ege-K 265 resulted in an 80% decolourisation of twofold-diluted OMW and a 30% decolourisation of undiluted OMW; in addition,
it was able to remove approximately 30% of all phenolic compounds in both twofold-diluted and undiluted OMW. We conclude that
A. tubingensis Ege-K 265 could be effectively used in the pre-treatment step of a combined aerobic-anaerobic process to solve the environmental
problems caused by OMW in Mediterranean countries. 相似文献
8.
S. Kumar Sunil Kumar S. P. Negi J. K. Kanwar 《In vitro cellular & developmental biology. Plant》2008,44(6):474-479
Callus cultures derived from leaf segments of chrysanthemum cultivar ‘Snow Ball’ which was susceptible to Septoria obesa were successfully used for in vitro selection for resistance to this pathogenic fungus. Resistant cell lines were selected by culturing callus on growth medium
containing various concentrations of S. obesa filtrate. Resistant calluses obtained after two cycles (30 d each cycle) of selection were used for plant regeneration. About
30% of the plants regenerated from the resistant calluses and 70–80% of the plants raised from cuttings had acquired considerable
resistance against the pathogen in the field. No phenotypic variation was observed in the selected regenerates. 相似文献
9.
S. E. Dawson 《Kew Bulletin》2008,63(3):517-517
Summary The name Pavetta modesta (Hiern) S. E. Dawson is a later homonym of P. modesta Bremek. Pavetta crystalensis is proposed as a new name. 相似文献
10.
Photolyase uses light energy to split UV-induced cyclobutane pyrimidine dimers in damaged DNA. This photoenzyme encompasses
a series of elementary dynamical processes during repair function from early photoinitiation by a photoantenna molecule to
enhance repair efficiency, to in vitro photoreduction through aromatic residues to reconvert the cofactor to the active form,
and to final photorepair to fix damaged DNA. The corresponding series of dynamics include resonance energy transfer, intraprotein
electron transfer, and intermolecular electron transfer, bond breaking-making rearrangements and back electron return, respectively.
We review here our recent direct studies of these dynamical processes in real time, which showed that all these elementary
reactions in the enzyme occur within subnanosecond timescale. Active-site solvation was observed to play a critical role in
the continuous modulation of catalytic reactions. As a model system for enzyme catalysis, we isolated the enzyme–substrate
complex in the transition-state region and mapped out the entire evolution of unmasked catalytic reactions of DNA repair.
These observed synergistic motions in the active site reveal a perfect correlation of structural integrity and dynamical locality
to ensure maximum repair efficiency on the ultrafast time scale. 相似文献
11.
12.
The tree-legume Leucaena leucocephala (leucaena) is used as a perennial fodder because of its fast-growing foliage, which is high in protein content. The use of
leucaena as a fodder is however restricted due to the presence of the toxin mimosine. Improvements in the nutritional contents
as well as other agronomic traits of leucaena can be accomplished through genetic transformation. The objective of this research
was to develop a transformation protocol for leucaena using phosphinothricin resistance as the plant selectable marker. Explants
obtained from immature zygotic embryos infected with the Agrobacterium tumefaciens strain C58C1 containing the binary plasmid pCAMBIA3201 produced four putative transformed leucaena plants. Transformation
was confirmed by PCR, RT-PCR, Southern blot, Western analyses, GUS-specific enzyme activity and herbicide leaf spraying assay.
A transformation efficiency of 2% was established using this protocol. 相似文献
13.
Despite the high isoform multiplicity of aquaporins in plants, with 35 homologues including 13 plasma membrane intrinsic proteins
(PIPs) in Arabidosis thaliana, the individual and integrated functions of aquaporins under various physiological conditions remain unclear. To better understand
aquaporin functions in plants under various stress conditions, we examined transgenic Arabidopsis and tobacco plants that constitutively overexpress Arabidopsis PIP1;4 or PIP2;5 under various abiotic stress conditions. No significant differences in growth rates and water transport
were found between the transgenic and wild-type plants when grown under favorable growth conditions. The transgenic plants
overexpressing PIP1;4 or PIP2;5 displayed a rapid water loss under dehydration stress, which resulted in retarded germination
and seedling growth under drought stress. In contrast, the transgenic plants overexpressing PIP1;4 or PIP2;5 showed enhanced
water flow and facilitated germination under cold stress. The expression of several PIPs was noticeably affected by the overexpression of PIP1;4 or PIP2;5 in Arabidopsis under dehydration stress, suggesting that the expression of one aquaporin isoform influences the expression levels of other
aquaporins under stress conditions. Taken together, our results demonstrate that overexpression of an aquaporin affects the
expression of endogenous aquaporin genes and thereby impacts on seed germination, seedling growth, and stress responses of
the plants under various stress conditions.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
14.
Plant aquaporins are believed to facilitate water transport across cell membranes. However, the relationship between aquaporins
and drought resistance in plants remains unclear. VfPIP1, a putative aquaporin gene, was isolated from Vicia faba leaf epidermis, and its expression was induced by abscisic acid (ABA). Our results indicated that the VfPIP1 protein was
localized in the plasma membrane, and its expression in V. faba was induced by 20% polyethylene glycol 6000. To further understand the function of VfPIP1, we obtained VfPIP1-expressing transgenic Arabidopsis thaliana plants under the control of the CaMV35S promoter. As compared to the wild-type control plants, the transgenic plants exhibited
a faster growth rate, a lower transpiration rate, and greater drought tolerance. In addition, the stomata of the transgenic
plants closed significantly faster than those of the control plants under ABA or dark treatment. These results suggest that
VfPIP1 expression may improve drought resistance of the transgenic plants by promoting stomatal closure under drought stress. 相似文献
15.
Dae-Sung Lee Min-Seung Kang Hye-Jin Hwang Sung-Hwan Eom Ji-Young Yang Myung-Suk Lee Won-Jae Lee You-Jin Jeon Jae-Sue Choi Young-Mog Kim 《Biotechnology and Bioprocess Engineering》2008,13(6):758-764
We have been attempting for some time to discover a compound evidencing antibacterial activity against methicillin-resistant
Staphylococcus aureus (MRSA). The dieckol isolated from Ecklonia stolonifera has been shown to exhibit antibacterial activity against methicillin-susceptible S. aureus (MSSA) and MRSA. The minimum inhibitory concentrations (MICs) of dieckol were determined in a range of 32 to 64 μg/mL against
standard MSSA and MRSA strains. Furthermore, dieckol clearly reversed the high-level ampicillin and penicillin resistance
of MRSA. The MICs of ampicillin against two standard strains of MRSA were dramatically reduced from 512 to 0.5 μg/mL in combination
with 1/4 MIC of dieckol (16 μg/mL). The fractional inhibitory concentration (FIC) indices of ampicillin and penicillin were
measured from 0.066 to 0.266 in combination with 8 or 16 μg/mL of dieckol against all tested MRSA strains, thereby suggesting
that dieckol-ampicillin or dieckol-penicillin combinations exert a synergistic effect against MRSA. The results of this study
indicate that dieckol, administered in combination with β-lactams, may prove effective in the treatment of MRSA infections.
Our finding may also contribute to the development of an alternative phytotherapeutic anti-MRSA agent. 相似文献
16.
Two rice cytosolic ascorbate peroxidases differentially improve salt tolerance in transgenic <Emphasis Type="Italic">Arabidopsis</Emphasis> 总被引:1,自引:0,他引:1
In order to determine the different roles of rice (Oryza sativa L.) cytosolic ascorbate peroxidases (OsAPXa and OsAPXb, GenBank accession nos. D45423 and AB053297, respectively) under salt stress, transgenic Arabidopsis plants over-expressing OsAPXa or OsAPXb were generated, and they all exhibited increased tolerance to salt stress compared to wild-type plants. Moreover, transgenic
lines over-expressing OsAPXb showed higher salt tolerance than OsAPXa transgenic lines as indicated by root length and total chlorophyll content. In addition to ascorbate peroxidase (APX) activity,
antioxidant enzyme activities of catalase (CAT), superoxide dismutase (SOD) and glutathione reductase (GR), which are also
involved in the salt tolerance process, and the content of H2O2 were also assayed in both transgenic and wild-type plants. The results showed that the overproduction of OsAPXb enhanced and maintained APX activity to a much higher degree than OsAPXa in transgenic Arabidopsis during treatment with different concentrations of NaCl, enhanced the active oxygen scavenging system, and protected plants
from salt stress by equilibrating H2O2 metabolism. Our findings suggest that the rice cytosolic OsAPXb gene has a more functional role than OsAPXa in the improvement of salt tolerance in transgenic plants.
Zhenqiang Lu and Dali Liu contributed equally. 相似文献
17.
Septobasidium parviflorae sp. nov. on Pinus parviflora is described and illustrated. This species is characterized by its whitish-gray, gray to dark gray-colored fungus body with
an indeterminate margin, hyphal strands, and cylindrical basidia with long sterigmata. This is the first report of Septobasidium occurring on a member of the genus Pinus in Japan. 相似文献
18.
Peter G. Wilson 《Kew Bulletin》2008,63(2):347-349
Summary The type specimen of Metrosideros regelii is discussed. It contains a mixture of two species, representing different genera, and a lectotype is chosen. The generic
position of the species is considered in the light of morphology and recent molecular evidence and the new combination, Mearnsia regelii, made. 相似文献
19.
L. Y. Solís-Ramos T. González-Estrada S. Nahuath-Dzib L. C. Zapata-Rodriguez E. Castaño 《Plant Cell, Tissue and Organ Culture》2009,96(3):279-287
Capsicum chinense is a recalcitrant species for in vitro morphogenesis, and up to date there is no efficient system for genetic transformation
and regeneration of this species via somatic embryogenesis. Here, we carried out an in vitro transformation of C. chinense via Agrobacterium tumefaciens co-cultivation with a system that expresses the heterologous gene WUSCHEL from Arabidopsis thaliana. WUSCHEL has been shown to promote the transition from vegetative to embryogenic state when overexpressed. We tested if the expression
of WUSCHEL in C. chinense would promote an embryogenic response in this species. After 15 days of induction, the segments of transformed stems begun
to form globular structures, suggesting that heterologus WUSCHEL was active and involved in the process of morphogenesis. 相似文献
20.
Water movement across cellular membranes is regulated largely by a family of water channel proteins called aquaporins (AQPs).
Since several abiotic stresses such as, drought, salinity and freezing, manifest themselves via altering water status of plant
cells and are linked by the fact that they all result in cellular dehydration, we overexpressed an AQP (tonoplast intrinsic
protein) from Panax ginseng, PgTIP1, in transgenic Arabidopsis
thaliana plants to test its role in plant’s response to drought, salinity and cold acclimation (induced freezing tolerance). Under
favorable conditions, PgTIP1 overexpression significantly increased plant growth as determined by the biomass production, and leaf and root morphology.
PgTIP1 overexpression had beneficial effect on salt-stress tolerance as indicated by superior growth status and seed germination
of transgenic plants under salt stress; shoots of salt-stressed transgenic plants also accumulated greater amounts of Na+ compared to wild-type plants. Whereas PgTIP1 overexpression diminished the water-deficit tolerance of plants grown in shallow (10 cm deep) pots, the transgenic plants
were significantly more tolerant to water stress when grown in 45 cm deep pots. The rationale for this contrasting response,
apparently, comes from the differences in the root morphology and leaf water channel activity (speed of dehydration/rehydration)
between the transgenic and wild-type plants. Plants overexpressed with PgTIP1 exhibited lower (relative to wild-type control) cold acclimation ability; however, this response was independent of cold-regulated
gene expression. Our results demonstrate a significant function of PgTIP1 in growth and development of plant cells, and suggest that the water movement across tonoplast (via AQP) represents a rate-limiting
factor for plant vigor under favorable growth conditions and also significantly affect responses of plant to drought, salt
and cold stresses. 相似文献