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991.
Priya Padmanabhan Mukund R. Shukla J. Alan Sullivan Praveen K. Saxena 《Plant Cell, Tissue and Organ Culture》2017,128(1):145-160
C4 plants can efficiently accumulate CO2 in leaves and thus reduce wasteful oxygen fixation by the RuBisCO enzyme. Three C4 enzymes, namely carbonic anhydrase (CA), phosphoenol pyruvate (PEPC) and pyruvate orthophosphate dikinase (PPDK), were over expressed in Oryza sativa L. ssp. indica var. Khitish under the control of green tissue specific promoters PD54o, PEPC and PPDK, respectively. Integration of these genes was confirmed by Southern hybridization. The relative expression of PEPC, CA and PPDK were, respectively, 6.75, 6.57 and 3.6-fold higher in transgenic plants compared to wild type plants (control). Photosynthetic efficiency of the transgenic plants increased significantly along with a 12?% increase in grain yield compared to wild type plants. Compared to control plants, transgenic plants also showed phenotypic changes such as increased leaf blade size, root biomass, and plant height and anatomical changes such as greater leaf vein number, bundle sheath cells, and bulliform cells. Our findings indicate that the combined over expression of these three enzymes is an efficient strategy for incorporating beneficial physiological and anatomical features that will enable subsequent yield enhancement in C3 rice plants. 相似文献
992.
Cobucci-Ponzano B Conte F Rossi M Moracci M 《Extremophiles : life under extreme conditions》2008,12(1):61-68
Glycoside hydrolases form hyperthermophilic archaea are interesting model systems for the study of catalysis at high temperatures
and, at the moment, their detailed enzymological characterization is the only approach to define their role in vivo. Family
29 of glycoside hydrolases classification groups α-l-fucosidases involved in a variety of biological events in Bacteria and Eukarya. In Archaea the first α-l-fucosidase was identified in Sulfolobus solfataricus as interrupted gene expressed by programmed −1 frameshifting. In this review, we describe the identification of the catalytic
residues of the archaeal enzyme, by means of the chemical rescue strategy. The intrinsic stability of the hyperthermophilic
enzyme allowed the use of this method, which resulted of general applicability for β and α glycoside hydrolases. In addition,
the presence in the active site of the archaeal enzyme of a triad of catalytic residues is a rather uncommon feature among
the glycoside hydrolases and suggested that in family 29 slightly different catalytic machineries coexist. 相似文献
993.
Eman M. Alissa Suhad M. Bahjri Waqar H. Ahmed Nabeel Al-Ama Gordon A. A. Ferns 《Biological trace element research》2009,131(3):215-228
Chromium deficiency is associated with impaired glucose tolerance (IGT) and dyslipidemia. Hence, the objective of the current
study was to investigate chromium status among Saudi men with and without established cardiovascular disease (CVD) and its
relationship to glucose tolerance, lipid profile and other established CVD risk factors. We measured serum and urine chromium
concentrations, fasted lipid profile, plasma glucose, and serum lipid peroxide in 130 Saudi men with an established history
of myocardial infarction and 130 age-matched controls without established CVD. Patients with established CVD had higher serum
triglycerides (p < 0.05) and plasma glucose (p < 0.0001) and lower serum and urinary chromium concentrations (p < 0.0001) than controls. Serum chromium was inversely correlated with plasma glucose among cases and controls (r = −0.189, p < 0.05 and r = −0.354, p < 0.00001, respectively). Plasma glucose (OR 1.127, CI 1.0–1.269, p < 0.05), serum chromium (OR 0.99, CI 0.985–0.995, p < 0.0001), and urinary chromium (OR 0.988, CI 0.981–0.995, p < 0.001) were independently associated with the presence of established coronary disease applying this model. While chromium
metabolism appears to be altered in individuals with CVD, it is unclear whether chromium supplementation would be effective
in CVD prevention among patients with IGT. This would need to be tested in long-term outcome trials. 相似文献
994.
The feasibility of using a two-stage autotrophic nitrogen removal process to treat sewage 总被引:1,自引:0,他引:1
The feasibility of using a two-stage autotrophic nitrogen removal process to treat sewage was examined in this study. The obtained results showed that total nitrogen (TN) could be efficiently removed by 88.38% when influent TN and chemical oxygen demand (COD) were 45.87 and 44.40 mg/L, respectively. In the first stage, nitritation was instantly achieved by the bioaugmentation strategy, and can be maintained under limited oxygen condition (below 0.2mg/L). The ratio of nitrite to ammonium in the effluent of the nitritation reactor can be controlled at approximate 1.0 by adjusting aeration rate. In the second stage, anammox was realized in the upflow anaerobic sludge blanket (UASB) reactor, where the total nitrogen removal rate was 0.40 kg Nm(-3)d(-1) under limited-substrate condition. Therefore, the organic matter in sewage can be firstly concentrated in biomass which could generate biogas (energy). Then, nitrogen in sewage could be removed in a two-stage autotrophic nitrogen removal process. 相似文献
995.
Chloroplasts are believed to be descendants of ancestral cyanobacteria that had peptidoglycan layer between the outer and the inner membranes. Historically, the glaucophyte Cyanophora paradoxa and the rhizopod Paulinella chromatophora were believed to harbor symbiotic cyanobacteria having peptidoglycan, which were conventionally named “cyanelles”. In addition, the complete set of genes involved in the synthesis of peptidoglycan has been found in the moss Physcomitrella patens and some plants and algae. The presence of peptidoglycan-like structures was demonstrated by a new metabolic labeling technique in P. patens. However, many green algae and all known red algae lack peptidoglycan-related genes. That is the reason why we questioned the origin of peptidoglycan-synthesizing enzymes in the chloroplasts of the green algae and plants. We performed phylogenetic analysis of ten enzymes involved in the synthesis of peptidoglycan exploiting the Gclust homolog clusters and additional genomic data. As expected, all the identified genes encoded in the chromatophore genome of P. chromatophora were closely related to cyanobacterial homologs. In the green algae and plants, only two genes, murA and mraY, were found to be closely related to cyanobacterial homologs. The origins of all other genes were diverse. Unfortunately, the origins of C. paradoxa genes were not clearly determined because of incompleteness of published genomic data. We discuss on the probable evolutionary scenarios to explain the mostly non-cyanobacterial origins of the biosynthetic enzymes of chloroplast peptidoglycan: A plausible one includes extensive multiple horizontal gene transfers during the early evolution of Viridiplantae. 相似文献
996.
Involvement of Matrix Metalloproteinases on the Inhibition of Cells Invasion and Migration by Emodin in Human Neuroblastoma SH-SY5Y Cells 总被引:1,自引:0,他引:1
Hsu-Feng Lu Kuang-Chi Lai Shu-Chun Hsu Hui-Ju Lin Chao-Lin Kuo Ching-Lung Liao Jai-Sing Yang Jing-Gung Chung 《Neurochemical research》2009,34(9):1575-1583
Emodin (1,3,8-trihydroxy-6-methylanthaquinone), an active component present in the root and rhizome of Rheum palmatum L. (Polygonaceae) has anti-bacterial, anti-tumor, diuretic and vasorelaxant effects. However, its mechanism of action on
the cell migration and invasion of human neuroblastoma cancer SH-SY5Y cells is not fully understood. In this study, firstly,
the effects of emodin on the percentage of viable cells were examined by using MTT assay and it was found that emodin induced
dose-and time-dependent inhibition in human neuroblastoma SH-SY5Y cells. Second, the effects of emodin on the migration and
invasion of SH-SY5Y cells were examined by using wound assay and matrigel counting and the results showed that emodin suppressed
the migration and invasion of SH-SY5Y cells. Third, we examined the effect of emodin on the levels of associated proteins
by using Western blotting and the results indicated that emodin inhibited the levels of GRB2, RhoA, HIF-1α, VEGF, FAK, iNOS,
COX2, p-p38, p-c-jun, MMP2, MMP9 and MMP7 but promoted the levels of PKC, PI3K, MEKK3 and NF-κB p65 that led to the inhibition
of migration and invasion of SH-SY5Y cells in vitro. 相似文献
997.
998.
褐飞虱、白背飞虱种间、种内密度制约效应研究 总被引:1,自引:1,他引:1
以高感品种TN1为材料.研究了褐飞虱、白背飞虱成、若虫密度对种群的制约效应。实验表明,单虫种一龄善虫密度15头/株和30头/株相比.褐飞虱成虫的羽化率、短翘率、体长和若虫历期均无明显差异,但成虫雌性比率前高;白背飞虱成虫羽化率前比后高21.22%.短翘率高15.25%。在两种飞虱一龄若虫密度30、45、60头/株等虫量混合组配下,褐飞虱成虫羽化率60头/株比30头/株下降28%,白背飞虱若虫历期以30头/株最长。在总虫量为30头/株时,种内(30头/株)和种间(15:15头/株)比.白背飞虱种内处理成虫羽化率高36.83%.昔虫历期短;褐飞虱以种内处理成虫短翘率高。从产卵位点来看.褐飞虱喜产在稻株叶鞘中下部厚肉组织上,白背飞虱以叶脉基部产卵为主.成虫密度2、4、8对/株3处理,其叶鞘、叶脉上的平均卵块变小;10天内的平均卵量亦减步。同密度下,种间组合比种内组合的产卵量多。从各指标对密度反应来看,褐飞虱比白背飞虱更耐拥挤。 相似文献
999.
Hwang IK Lee CH Li H Yoo KY Choi JH Kim DW Kim DW Suh HW Won MH 《Neurochemical research》2008,33(7):1309-1315
Similarities between age-related changes in the canine and human brain have resulted in the general acceptance of the canine brain as a model of human brain aging. The hippocampus is essentially required for intact cognitive ability and appears to be particularly vulnerable to the aging process. We observed changes in ionized calcium-binding adapter molecule 1 (Iba-1, a microglial marker) immunoreactivity and protein levels in the hippocampal dentate gyrus and CA1 region of adult (2-3 years) and aged (10-12 years) dogs. We also observed the interferon-gamma (IFN-gamma), a pro-inflammatory cytokine, protein levels in these groups. In the dentate gyrus and CA1 region of the adult dog, Iba-1 immunoreactive microglia were well distributed and their processes were highly ramified. However, in the aged dog, the processes of Iba-1 immunoreactive microglia were hypertrophied in the dentate gyrus. Moreover, Iba-1 protein level in the dentate gyrus in the aged dog was higher than in the adult dog. IFN-gamma expression was increased in the dentate gyrus homogenates of aged dogs than adult dogs. In addition, we found that some neurons were positive to Fluoro-Jade B (a marker for neuronal degeneration) in the dentate polymorphic layer, but not in the hippocampal CA1 region in the aged dog. These results suggest that Iba-1 immunoreactive microglia are hypertrophied in the dentate gyrus in the aged dog. 相似文献
1000.
羊草种群地上部生物量与株高的分形关系 总被引:26,自引:4,他引:26
应用分形几何学(Fractal geometry)的原理和方法对羊草(Aneurolepidium chi- nense)种群地上部生物量与株高的关系进行了研究.结果表明.羊草种群的地上部生物量 与株高存在很好的静态分形关系,所得分形维数是对地上部生物量在各器官中积累规律 (生物量配比)的表征;羊草种群地上部生物量与株高的动态分形关系表明在整个生长季 内该种群地上部生物量的增长具有自相似性.是一个分形生长过程,增长规律为分形维数 值D;在此基础上建立了羊草种群的分形生长模式.认为成熟植株可以看作是其幼苗经生 长放大过程而得到的. 相似文献