排序方式: 共有35条查询结果,搜索用时 62 毫秒
21.
Jolanta Patamsytė Donatas Naugžemys Tatjana Čėsnienė Violeta Kleizaitė Olga N. Demina Svetlana I. Mikhailova Vladimir A. Agafonov Donatas Žvingila 《Plant Ecology》2018,219(1):101-114
We studied the invasive warty cabbage Bunias orientalis (Brassicaceae) in three geographically distinct areas. Using inter-simple sequence repeat fingerprinting, we analyzed warty cabbages, including non-native populations, from the eastern Baltic and western Siberian regions and native populations from southwestern Russia. The eastern Baltic region and western Siberia represent the two opposite directions of B. orientalis spread in climatically different zones. The genetic structures of the native and non-native B. orientalis populations were assessed through analysis of molecular variance (AMOVA) and the Bayesian clustering method and by determining the main measures of genetic diversity. AMOVA revealed considerable population differentiation in both the native and invasive ranges. Our results did not indicate a decrease in genetic diversity in the non-native populations of B. orientalis. Similar measures of genetic diversity and genetic structure were determined in the invasive populations in two geographically and ecologically distinct, non-native regions located in Europe and Asia. In both of these regions, higher genetic diversity was detected in the non-native populations than in the native region populations, which may be due to multiple introductions. However, Bayesian clustering analysis revealed slightly different sources of invasive populations in the two non-native regions. Genetic diversity patterns revealed the lack of isolation by distance between populations and confirmed the influence of anthropogenic factors on the spread of B. orientalis. The significance of native populations as germplasm resources for breeding is discussed. 相似文献
22.
Polívka T van Stokkum IH Zigmantas D van Grondelle R Sundström V Hiller RG 《Biochemistry》2006,45(28):8516-8526
Carbonyl carotenoids are important constituents of the antenna complexes of marine organisms. These carotenoids possess an excited state with a charge-transfer character (intramolecular charge transfer state, ICT), but many details of the carotenoid to chlorophyll energy transfer mechanisms are as yet poorly understood. Here, we employ femtosecond transient absorption spectroscopy to study energy transfer pathways in the intrinsic light-harvesting complex (LHC) of dinoflagellates, which contains the carbonyl carotenoid peridinin. Carotenoid to chlorophyll energy transfer efficiency is about 90% in the 530-550 nm region, where the peridinin S2 state transfers energy with an efficiency of 25-50%. The rest proceeds via the S1/ICT channel, and the major S1/ICT-mediated energy transfer pathway utilizes the relaxed S1/ICT state and occurs with a time constant of 2.6 ps. Below 525 nm, the overall energy transfer efficiency drops because of light absorption by another carotenoid, diadinoxanthin, that contributes only marginally to energy transfer. Instead, its role is likely to be photoprotection. In addition to the peridinin-Chl-a energy transfer, it was shown that energy transfer also occurs between the two chlorophyll species in LHC, Chl-c2, and Chl-a. The time constant characterizing the Chl-c2 to Chl-a energy transfer is 1.4 ps. The results demonstrate that the properties of the S1/ICT state specific for carbonyl carotenoids is the key to ensure the effective harvesting of photons in the 500-600 nm region, which is of vital importance to underwater organisms. 相似文献
23.
A simple procedure basically applicable for the quantitative determination of activity of all restriction endonucleases is described. Native DNA immobilized on cellulose is used as a substrate; after the treatment by restriction endonucleases this DNA is released to the solution. Changes of the optical density of the solution containing solubilized DNA permit quantitative determination of the restriction endonuclease activity. 相似文献
24.
Fisher BJ Kraskauskas D Martin EJ Farkas D Wegelin JA Brophy D Ward KR Voelkel NF Fowler AA Natarajan R 《American journal of physiology. Lung cellular and molecular physiology》2012,303(1):L20-L32
Bacterial infections of the lungs and abdomen are among the most common causes of sepsis. Abdominal peritonitis often results in acute lung injury (ALI). Recent reports demonstrate a potential benefit of parenteral vitamin C [ascorbic acid (AscA)] in the pathogenesis of sepsis. Therefore we examined the mechanisms of vitamin C supplementation in the setting of abdominal peritonitis-mediated ALI. We hypothesized that vitamin C supplementation would protect lungs by restoring alveolar epithelial barrier integrity and preventing sepsis-associated coagulopathy. Male C57BL/6 mice were intraperitoneally injected with a fecal stem solution to induce abdominal peritonitis (FIP) 30 min prior to receiving either AscA (200 mg/kg) or dehydroascorbic acid (200 mg/kg). Variables examined included survival, extent of ALI, pulmonary inflammatory markers (myeloperoxidase, chemokines), bronchoalveolar epithelial permeability, alveolar fluid clearance, epithelial ion channel, and pump expression (aquaporin 5, cystic fibrosis transmembrane conductance regulator, epithelial sodium channel, and Na(+)-K(+)-ATPase), tight junction protein expression (claudins, occludins, zona occludens), cytoskeletal rearrangements (F-actin polymerization), and coagulation parameters (thromboelastography, pro- and anticoagulants, fibrinolysis mediators) of septic blood. FIP-mediated ALI was characterized by compromised lung epithelial permeability, reduced alveolar fluid clearance, pulmonary inflammation and neutrophil sequestration, coagulation abnormalities, and increased mortality. Parenteral vitamin C infusion protected mice from the deleterious consequences of sepsis by multiple mechanisms, including attenuation of the proinflammatory response, enhancement of epithelial barrier function, increasing alveolar fluid clearance, and prevention of sepsis-associated coagulation abnormalities. Parenteral vitamin C may potentially have a role in the management of sepsis and ALI associated with sepsis. 相似文献
25.
D. Levisauskas 《Biotechnology letters》2001,23(15):1189-1195
Inferential control algorithms and systems for set-point control of the specific growth rate in fed-batch cultivation processes are presented. Realization of the proposed control systems does not require mathematical model and a priori knowledge of the culture of microorganisms under control. Feed-back signal in PID control loops of the investigated systems is based on measurements of the O2 concentration in exhaust gas and the air supply rate, however, measurements of the other technological parameters related to the culture growth dynamics can also be applied. 相似文献
26.
Mizuno S Yasuo M Bogaard HJ Kraskauskas D Natarajan R Voelkel NF 《American journal of physiology. Lung cellular and molecular physiology》2011,300(3):L402-L413
In patients with chronic obstructive pulmonary disease (COPD), histone deacetylase (HDAC) expression and activity are reduced in the lung tissue. However, whether HDAC activity controls the maintenance of the lung alveolar septal structures has not been investigated. To explore the consequences of HDAC inhibition and address the question of whether HDAC inhibition causes lung cell apoptosis and emphysema, male Sprague-Dawley rats and human pulmonary microvascular endothelial cells (HPMVEC) were treated with trichostatin A (TSA), a specific inhibitor of HDACs. Chronic TSA treatment increased the alveolar air space area, mean linear intercept, and the number of caspase-3-positive cells in rat lungs. TSA suppressed hypoxia-inducible factor-1α (HIF-1α), VEGF, and lysyl oxidase (LOX) and increased microtubule-associated protein-1 light chain 3 (LC3), p53, and miR34a microRNA expression in both rat lungs and cultured HPMVEC. Gene silencing of HDAC2 using small interfering RNA (siRNA) in cultured HPMVEC resulted in the suppression of HIF-1α, VEGF, and LOX and an increase of p53 expression. These data indicate that HDAC inhibition causes emphysema and that HDAC-dependent mechanisms contribute to the maintenance of the adult lung structure. Our results also suggest that the increase in apoptosis, as a consequence of HDAC inhibition, is associated with decreased VEGF and HIF-1α expression. 相似文献
27.
Homologous recombination between plasmid and chromosomal DNA in Bacillus subtilis requires approximately 70 bp of homology 总被引:11,自引:0,他引:11
Fuat K. Khasanov Donatas J. Zvingila Almaz A. Zainullin Alexander A. Prozorov Vladimir I. Bashkirov 《Molecular & general genetics : MGG》1992,234(3):494-497
Summary To determine the minimal DNA sequence homology required for recombination in Bacillus subtilis, we developed a system capable of distinguishing between homologous and illegitimate recombination events during plasmid integration into the chromosome. In this system the recombination frequencies were measured between is pE194 derivatives carrying segments of the chromosomal -gluconase gene (bglS) of various lengths and the bacterial chromosome, using selection for erythromycin resistance at the non-permissive temperature. Homologous recombination events, resulting in disruption of the bglS gene, were easily detected by a colorimetric assay for -gluconase activity. A linear dependence of recombination frequency on homology length was observed over an interval of 77 bp. It was found that approximately 70 bp of homology is required for detectable homologous recombination. Homologous recombination was not detected when only 25 by of homology between plasmid and chromosome were provided. The data indicate that homology requirements for recombination in B. subtilis differ from those in Escherichia coli. 相似文献
28.
Donatas Levišauskas 《Biotechnology Techniques》1995,9(2):85-90
An effective automatic control algorithm for set-point control of dissolved oxygen concentration in batch culture has been developed. Adaptation of PI controller to the variable state of batch culture is based on analytically obtained functional relations between the controller parameters and the state variables: oxygen uptake rate, stirring speed, and saturation value of dissolved oxygen concentration, which are measured or estimated on-line. Results of experimental investigation of the adaptive control system are presented. 相似文献
29.
Zeaxanthin radical cation formation in minor light-harvesting complexes of higher plant antenna 总被引:1,自引:0,他引:1
Avenson TJ Ahn TK Zigmantas D Niyogi KK Li Z Ballottari M Bassi R Fleming GR 《The Journal of biological chemistry》2008,283(6):3550-3558
Previous work on intact thylakoid membranes showed that transient formation of a zeaxanthin radical cation was correlated with regulation of photosynthetic light-harvesting via energy-dependent quenching. A molecular mechanism for such quenching was proposed to involve charge transfer within a chlorophyll-zeaxanthin heterodimer. Using near infrared (880-1100 nm) transient absorption spectroscopy, we demonstrate that carotenoid (mainly zeaxanthin) radical cation generation occurs solely in isolated minor light-harvesting complexes that bind zeaxanthin, consistent with the engagement of charge transfer quenching therein. We estimated that less than 0.5% of the isolated minor complexes undergo charge transfer quenching in vitro, whereas the fraction of minor complexes estimated to be engaged in charge transfer quenching in isolated thylakoids was more than 80 times higher. We conclude that minor complexes which bind zeaxanthin are sites of charge transfer quenching in vivo and that they can assume Non-quenching and Quenching conformations, the equilibrium LHC(N) <==> LHC(Q) of which is modulated by the transthylakoid pH gradient, the PsbS protein, and protein-protein interactions. 相似文献
30.
Jolanta Patamsytė Violeta Kleizaitė Tatjana Čėsnienė Vytautas Rančelis Donatas Žvingila 《Central European Journal of Biology》2010,5(4):496-506
The red raspberry (Rubus idaeus L.) is widely distributed in Lithuania and occupies a range of habitats. The presence of coadapted gene pools in local populations
of R. idaeus is a question of interest not only to plant scientists, but also to plant breeders. In this study, we investigated the genetic
structure of R. idaeus and the influence of local habitats on the genetic diversity within and among populations. Nineteen populations of R. idaeus were sampled from different habitats in various agroclimatic subregions of Lithuania, and analyzed using RAPD markers. 113
RAPD bands were identified among 315 individuals; 84.31% of these were polymorphic. The mean values of Shannon’s information
index for different populations ranged from 0.341 to 0.455. Nei’s gene diversity established within populations averaged 0.266.
An AMOVA revealed 74% of genetic variation among individuals within populations of R. idaeus, and 23% among populations. The remaining genetic variation was distributed among populations from different agroclimatic
subregions (3%). The results of this study suggest that the genetic structure of R. idaeus populations in Lithuania may be influenced partially by isolation by distance as well as by local environmental conditions. 相似文献