排序方式: 共有163条查询结果,搜索用时 0 毫秒
1.
Magdolna Varsányi Andreja Vrbica Ludwig M. G. Heilmeyer Jr. 《Biochemical genetics》1980,18(3-4):247-261
A new mouse strain, the V strain, with a partial deficiency of phosphorylase kinase has been established. The deficiency is caused by an X-linked dominant gene (Phk
c
). Muscle extracts of homozygous and heterozygous females and hemizygous males have about 25% of the activity found in extracts of normal (C3H/HeHan) mice. This dominant phosphorylase kinase deficiency of the new V strain is different from that of the I-strain mice with the X-linked recessive deficiency of skeletal muscle phosphorylase kinase. The muscle extracts of V-strain and normal mice contain the same phosphorylase phosphatase activity of about 1 U/mg. Heart and liver extracts from V mice contained about 50% and 66%, respectively, of the phosphorylase kinase activity compared to that found in the same organs from the normal mice. The glycogen content of the skeletal muscle of the V strain was normal, i.e., 0.9 mg/g. Phosphorylase kinase was purified from the skeletal muscle of the V strain by (a) hydrophobic chromatography on methylamine Sepharose, (b) ammonium sulfate precipitation, and (c) gel filtration of Sepharose 4B. The enzyme has a similar structure to the normal murine and rabbit skeletal muscle enzyme, except that the proportion of the subunits differs. The molar ratio of the subunits of the V strain mice is (+)::=0.54:1:1.169, in comparison with that of the rabbit (+)::=1.1:1.0:1.0 and that of normal murine enzyme 0.9:1.0:0.7.This work was supported by the Minister für Wissenschaft und Forschung des Landes Nordrhein-Westfalen, West Germany and of the Fonds der Chemie, West Germany, and forms part of the md thesis of A. Vrbica. 相似文献
2.
3.
Vincent D Du Fall LA Livk A Mathesius U Lipscombe RJ Oliver RP Friesen TL Solomon PS 《Molecular Plant Pathology》2012,13(5):467-482
In this study, proteomics and metabolomics were used to study the wheat response to exposure to the SnToxA effector protein secreted by the fungal pathogen Stagonospora nodorum during infection. Ninety-one different acidic and basic proteins and 101 metabolites were differentially abundant when comparing SnToxA- and control-treated wheat leaves during a 72-h time course. Proteins involved in photosynthesis were observed to increase marginally initially after exposure, before decreasing rapidly and significantly. Proteins and metabolites associated with the detoxification of reactive oxygen species in the chloroplast were also differentially abundant during SnToxA exposure, implying that the disruption of photosynthesis causes the rapid accumulation of chloroplastic reactive oxygen species. Metabolite profiling revealed major metabolic perturbations in central carbon metabolism, evidenced by significant increases in tricarboxylic acid (TCA) cycle intermediates, suggestive of an attempt by the plant to generate ATP and reducing equivalents in response to the collapse of photosynthesis caused by SnToxA. This was supported by the observation that the TCA cycle enzyme malate dehydrogenase was up-regulated in response to SnToxA. The infiltration of SnToxA also resulted in a significant increase in abundance of many pathogenicity-related proteins, even in the absence of the pathogen or other pathogen-associated molecular patterns. This approach highlights the complementary nature of proteomics and metabolomics in studying effector-host interactions, and provides further support for the hypothesis that necrotrophic pathogens, such as S. nodorum, appear to exploit existing host cell death mechanisms to promote pathogen growth and cause disease. 相似文献
4.
Tanja Dolinsek Bostjan Markelc Gregor Sersa Andrej Coer Monika Stimac Jaka Lavrencak Andreja Brozic Simona Kranjc Maja Cemazar 《PloS one》2013,8(3)
Endoglin is a transforming growth factor-β (TGF- β) co-receptor that participates in the activation of a signaling pathway that mediates endothelial cell proliferation and migration in angiogenic tumor vasculature. Therefore, silencing of endoglin expression is an attractive approach for antiangiogenic therapy of tumors. The aim of our study was to evaluate the therapeutic potential of small interfering RNA (siRNA) molecules against endoglin in vitro and in vivo. Therapeutic potential in vitro was assessed in human and murine endothelial cells (HMEC-1, 2H11) by determining endoglin expression level, cell proliferation and tube formation. In vivo, the therapeutic potential of siRNA molecules was evaluated in TS/A mammary adenocarcinoma growing in BALB/c mice. Results of our study showed that siRNA molecules against endoglin have a good antiangiogenic therapeutic potential in vitro, as expression of endoglin mRNA and protein levels in mouse and human microvascular endothelial cells after lipofection were efficiently reduced, which resulted in the inhibition of endothelial cell proliferation and tube formation. In vivo, silencing of endoglin with triple electrotransfer of siRNA molecules into TS/A mammary adenocarcinoma also significantly reduced the mRNA levels, number of tumor blood vessels and the growth of tumors. The obtained results demonstrate that silencing of endoglin is a promising antiangiogenic therapy of tumors that could not be used as single treatment, but as an adjunct to the established cytotoxic treatment approaches. 相似文献
5.
Jernej Jakse Andreja Cerenak Sebastjan Radisek Zlatko Satovic Zlata Luthar Branka Javornik 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2013,126(6):1431-1443
Verticillium wilt (VW) can cause substantial yield loss in hop particularly with the outbreaks of the lethal strain of Verticillium albo-atrum. To elucidate genetic control of VW resistance in hop, an F1 mapping population derived from a cross of cultivar Wye Target, with the predicted genetic basis of resistance, and susceptible male breeding line BL2/1 was developed to assess wilting symptoms and to perform QTL mapping. The genetic linkage map, constructed with 203 markers of various types using a pseudo-testcross strategy, formed ten major linkage groups (LG) of the maternal and paternal maps, covering 552.98 and 441.1 cM, respectively. A significant QTL for VW resistance was detected at LOD 7 on a single chromosomal region on LG03 of both parental maps, accounting for 24.2–26.0 % of the phenotypic variance. QTL analysis for alpha-acid content and yield parameters was also performed on this map. QTLs for these traits were also detected and confirmed our previously detected QTLs in a different pedigree and environment. The work provides the basis for exploration of QTL flanking markers for possible use in marker-assisted selection. 相似文献
6.
Andreja Radović Vassiliki Kati Melita Perčec Tadić Damijan Denac Dražen Kotrošan 《Bird Study》2013,60(1):106-114
Capsule Spatial environmental modelling well predicted nesting distribution of the White stork in Southeast Europe and can be used in conservation planning with respect to climate change.Aims To create spatial models for predicting White Stork presence and densities in the Southeast Europe to identify areas of suitable habitat for White Storks.Methods We quantified the habitat used by nesting White storks in Southeast Europe. Using spatial modelling, we defined a set of free and available online environmental variables that predict the breeding localities of the species. We employed pseudo-absences and the kriging of the residuals in order to create predictive models of nest presence and density.Results The presence–absence model was found to be precise in predicting the presence of nests. Both density and presence of breeding pairs were best explained negatively by elevation, slope, minimum temperature during May, and distance to the nearest human settlement and positively by topographic wetness index, total area of human settlement and spring precipitation.Conclusion Our robust and easily repeatable models offer a conservation tool to reveal suitable but unoccupied localities for breeding White Storks pairs which may inform our understanding of how climate change might affect the species' distribution in the future. For example, protecting White Storks on the Dalmatian coast may become even more significant in the future, because the Dalmatian coast is predicted as the only suitable breeding area in Croatia later this century. 相似文献
7.
Jernej Polajnar Andreja Kavčič Alenka Žunič Kosi Andrej Čokl 《Central European Journal of Biology》2013,8(7):670-680
Palomena prasina is interesting for the study of vibrational communication within the Pentatomid subfamily Pentatominae, because its host range is limited to woody plants, unlike the better known Nezara viridula, whose vibrational communication is commonly used as a model for the whole family. The vibrational repertoire of P. prasina was described several decades ago and is redescribed in this paper using modern methods for non-contact vibration recording. Additionally, we hypothesized that this species has retained the capacity for signal frequency variation necessary for tuning to resonance properties of various host plants of Pentatominae, but if the signals are emited in the absence of mechanical feedback, they are tuned more specifically to their native acoustic environment — woody plants. By recording live bugs signalling on different substrates and comparing spectral properties of their signals among substrates, we found that there is a match between the signals emitted on a woody branch and those emitted on a non-resonant surface, while spectral properties of signals emitted on herbaceous plants differ. Our findings provide evidence in support of the signal tuning hypothesis and shed further light on the crucial role of substrate in vibrational communication of insects. 相似文献
8.
Mateja Felicijan Janja Kristl Andreja Urbanek Krajnc 《Trees - Structure and Function》2016,30(6):2117-2129
Keymessage
The temporal gradations of the investigated phenolics in Norway spruce bark after bark beetle (Ips typographus) attack followed the general eco-physiological concept. Treatment with salicylic acid inhibits bark beetle colonisation, alleviates the phenolic responses and activates the synthesis of condensed tannins on later sampling dates.Abstract
Conifer bark is the target of numerous organisms due to its assimilated transport and nutrient storage functions. In the presented study, 100 mM salicylic acid (SA) was applied onto Norway spruce stems prior to being infested with bark beetles (Ips typographus L.), to study the temporal gradation of changes in condensed tannins (CT) and total phenolics (tPH) and their significance for mediating stress-tolerance. A significant accumulation of CT was monitored in untreated trees in response to progressive bark beetle infestation occurring from May onwards. In SA-treated infested trees, the CT values remained at control levels until May, but after the re-treatment of infested trees in June, the concentrations of CT rose significantly in comparison to the controls. The tPH values dropped 16 days after SA-treatment, independent of infestation, and later on remained at control level until July. In contrast, tPH contents accumulated in untreated infested trees in May, eased in June and increased again in July, when the trees were affected by the second generation of bark beetles. To sum up, in May and July when the highest beetle-flight activity was monitored the metabolic shift of phenolics within untreated infested trees differed significantly from the response of SA-treated trees. In addition, on SA-treated trees less entrance holes were monitored over the whole period of sampling when compared to untreated infested trees. These results provide evidence that SA-treatment alleviates the phenolic responses, activates the synthesis of condensed tannins and inhibits bark beetle colonisation.9.
Temporal and spatial dimensions of postnatal growth of the mouse urinary bladder urothelium 总被引:1,自引:1,他引:0
Postnatal growth and renewal of mouse urothelium start on the day of birth. In the present study, temporal and spatial dimensions of urothelial growth were studied during the first two postnatal weeks. Quantitative analysis showed that the rate of urothelial cell proliferation is significantly higher during all 14 postnatal days than in adult mice. Three peaks of proliferative and mitotic activity were revealed: on the day of birth and postnatal day 1, on days 6 and 7, and on day 14. The high proliferation rate around the day of birth and at postnatal days 6 and 7 coincides with cell death in the urothelium. Semiquantitative analysis showed that during all 14 postnatal days, the urothelial proliferative response is mostly confined to the basal cell layer. Urothelial cells divide predominantly in parallel to the plain of the urothelium on all chosen postnatal days. Increased portions of urothelial cells, dividing perpendicularly to the urothelium were observed only on the day of birth and on postnatal day 7. Our results suggest that postnatal growth of mouse urothelium is particularly the result of an increasing number of cells in individual cell layers and not the result of an increasing number of cell layers. 相似文献
10.
Constitutive versus thermoinducible expression of heterologous proteins in Escherichia coli based on strong PR,PL promoters from phage lambda 总被引:1,自引:0,他引:1
Constitutive and thermoinducible expression plasmids based on strong P(R),P(L) promoters from phage lambda were compared for production of TNF-alpha and its analogs under various conditions. Much higher accumulation of TNF was obtained in a constitutive system, so the wider applicability of such systems was studied. In constitutive systems, proteolytically susceptible proteins can be produced easily at low cultivation temperatures and the addition of expensive or toxic chemical inducers is not required. On the other hand, toxic proteins cannot be produced and selection pressure must be strictly maintained to ensure segregational stability of plasmids. Accumulation of TNF-alpha and various analogs at levels up to 25% of total soluble protein was repeatedly achieved, which was 2-3-fold higher than in a thermoinducible system. The stable behavior of the constitutive system in laboratory fermentors was also confirmed. We propose the constitutive system described here as a general model for many currently used expression systems containing strong but not completely repressed promoters. Such systems may be considered as constitutive ones with reduced promoter strengths, but still exhibiting all the intrinsic properties of constitutive expression systems. Although all modern expression systems are inducible, wider use of a constitutive system is evidently possible. 相似文献