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排序方式: 共有253条查询结果,搜索用时 250 毫秒
91.
92.
Lincoln?SmithEmail author Massimo?Cristofaro Marie-Claude?Bon Alessio?De Biase Radmila?Petanovi? Biljana?Vidovi? 《BioControl》2018,63(3):417-425
Classical biological control of weeds depends on finding agents that are highly host-specific. This requires not only correctly understanding the identity of the target plant, sometimes to subspecific levels, in order to find suitable agents, but also identifying agents that are sufficiently specific to be safe and effective. Behavioral experiments and molecular genetic tools have revealed that some arthropod species previously thought to be polyphagous really consist of multiple cryptic species, host races or biotypes, some of which are more host-specific than others. Whereas true species are reproductively isolated, individuals from subspecific populations may potentially interbreed with those of other populations if they should encounter them. Furthermore, biotypes may consist of individuals sharing a genotype that is not fixed within a monophyletic group, and thus may not be evolutionarily stable. This raises the question of how such populations should be classified, and how to confirm the identity of live arthropods before releasing them as classical biological control agents. The existence of host races or cryptic species may greatly increase the number of prospective biological control agents available. However, it may also create new challenges for governmental regulation. These issues are discussed using pertinent examples, mainly from North America. 相似文献
93.
Internal symptoms in epidermal cells of tobacco rattle virus infected tobacco were investigated. Ring-, elipsoid- and spindle-shaped inclusions were found in the period between the fourth and thirtieth day after inoculation of Samsun seedlings. 相似文献
94.
Zusammenfassung Mit dem Gewebesaft vonOpuntia brasiliensis, die neben cytoplasmatischen Eiweißspindeln noch Zellkernkristalloide enthielt, wurde ein spindelfreiesEpiphyllum infiziert. Nach einiger Zeit (ca. 3 Wochen) erschienen im infiziertenEpiphyllum nicht mir die cytoplasmatischen Eiweißspindeln. sondern auch die Kernkristalloide.In den Vakuolen der erwähntenOpuntia wie auch in denen vonEpiphyllum wurden kristallinische Eiweißdrusen beobachtet, die auch als vom Virus bedingte Zelleinschlüsse aufgefaßt werden. 相似文献
95.
Expression of A152T human tau causes age‐dependent neuronal dysfunction and loss in transgenic mice
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Sumihiro Maeda Biljana Djukic Praveen Taneja Gui‐Qiu Yu Iris Lo Allyson Davis Ryan Craft Weikun Guo Xin Wang Daniel Kim Ravikumar Ponnusamy T Michael Gill Eliezer Masliah Lennart Mucke 《EMBO reports》2016,17(4):530-551
A152T‐variant human tau (hTau‐A152T) increases risk for tauopathies, including Alzheimer's disease. Comparing mice with regulatable expression of hTau‐A152T or wild‐type hTau (hTau‐WT), we find age‐dependent neuronal loss, cognitive impairments, and spontaneous nonconvulsive epileptiform activity primarily in hTau‐A152T mice. However, overexpression of either hTau species enhances neuronal responses to electrical stimulation of synaptic inputs and to an epileptogenic chemical. hTau‐A152T mice have higher hTau protein/mRNA ratios in brain, suggesting that A152T increases production or decreases clearance of hTau protein. Despite their functional abnormalities, aging hTau‐A152T mice show no evidence for accumulation of insoluble tau aggregates, suggesting that their dysfunctions are caused by soluble tau. In human amyloid precursor protein (hAPP) transgenic mice, co‐expression of hTau‐A152T enhances risk of early death and epileptic activity, suggesting copathogenic interactions between hTau‐A152T and amyloid‐β peptides or other hAPP metabolites. Thus, the A152T substitution may augment risk for neurodegenerative diseases by increasing hTau protein levels, promoting network hyperexcitability, and synergizing with the adverse effects of other pathogenic factors. 相似文献
96.
Wayne Murrell Emily Palmero John Bianco Biljana Stangeland Mrinal Joel Linda Paulson Bernd Thiede Zanina Grieg Ingunn Ramsnes H?vard K. Skjellegrind St?le Nyg?rd Petter Brandal Cecilie Sandberg Einar Vik-Mo Sheryl Palmero Iver A. Langmoen 《PloS one》2013,8(8)
The discovery of stem cells in the adult human brain has revealed new possible scenarios for treatment of the sick or injured brain. Both clinical use of and preclinical research on human adult neural stem cells have, however, been seriously hampered by the fact that it has been impossible to passage these cells more than a very few times and with little expansion of cell numbers. Having explored a number of alternative culturing conditions we here present an efficient method for the establishment and propagation of human brain stem cells from whatever brain tissue samples we have tried. We describe virtually unlimited expansion of an authentic stem cell phenotype. Pluripotency proteins Sox2 and Oct4 are expressed without artificial induction. For the first time multipotency of adult human brain-derived stem cells is demonstrated beyond tissue boundaries. We characterize these cells in detail in vitro including microarray and proteomic approaches. Whilst clarification of these cells’ behavior is ongoing, results so far portend well for the future repair of tissues by transplantation of an adult patient’s own-derived stem cells. 相似文献
97.
Nataša Vučinić Igor Djan Edita Stokić Biljana Božin Dragana Obreht Karmen Stankov Mihajla Djan 《Molecular biology reports》2014,41(8):5221-5227
The metabolic syndrome (MetS) is a polygenic multifactorial metabolic disorder with strong socioeconomic influence. MetS has became a worldwide epidemic, that directly increases the risk of cardiovascular diseases and type 2 diabetes mellitus. The human apoE gene, coding Apolipoprotein E, has three common polymorphisms in human population: e2, e3 and e4, which are proved to be associated with impaired lipid metabolism. The contribution of apoE polymorphism to MetS disorders has not been investigated previously in Vojvodina Province, region with the highest number of obese people in Serbia. The aim of this study was to evaluate apoE gene polymorphism in relation to MetS disorders. The healthy control group of 30 individuals and 63 MetS patients were examined for apoE variants in relation to biochemical and anthropometric parameters. The genotypes were determined by PCR–RFLP. Regarding all parameters, significantly higher values were detected in MetS group compared to control. The MetS group of patients had significantly higher frequency of e4 allele. In addition, positive relation was revealed between e4 allele presence and all measured parameters. It was found that the e4 allele was related with a significantly increased OR of MetS disorders according to the International Diabetes Federation definition. These results suggested that e4 allele may act as a one of determinants for development of metabolic syndrome. 相似文献
98.
Suzana Dinevska-Kjovkarovska Teuta Guladin Biljana Miova Slavco Mitev Katerina Gerazova 《Journal of thermal biology》2009
We examined the effect of acclimation to moderate hyperthermic environment on the ACTH, TSH, T3, T4 and corticosterone level, as well as the relative weight of hypophysis, thyroid and adrenal glands in streptozotocin-diabetic rats. Increased activity of the hypothalamo-pituitary-adrenocortical (HPA) axis has been demonstrated in diabetic animals, whereas insulin treatment restores the changes. Heat acclimation reduces the level of ACTH and corticosterone in control animals and moderates the hormonal disturbances caused by diabetes. Simultaneously, our study revealed impairment in the activity of the hypothalamo-pituitary-thyroid (HPT) axis. Acclimation to 35±1 °C resulted in significantly lower T3 and T4 levels in control, diabetic and insulin-treated animals. Relative weight of the hypophysis, thyroid and adrenal glands is decreased in heat-acclimated rats. Our assumption is that there might be a cross tolerance between diabetes and heat acclimation on a hormonal level. 相似文献
99.
Kukavica Biljana; Mojovic Milos; Vuccinic Zeljko; Maksimovic Vuk; Takahama Umeo; Jovanovic Sonja Veljovic 《Plant & cell physiology》2009,50(2):304-317
The hydroxyl radical produced in the apoplast has been demonstratedto facilitate cell wall loosening during cell elongation. Cellwall-bound peroxidases (PODs) have been implicated in hydroxylradical formation. For this mechanism, the apoplast or cellwalls should contain the electron donors for (i) H2O2 formationfrom dioxygen; and (ii) the POD-catalyzed reduction of H2O2to the hydroxyl radical. The aim of the work was to identifythe electron donors in these reactions. In this report, hydroxylradical (·OH) generation in the cell wall isolated frompea roots was detected in the absence of any exogenous reductants,suggesting that the plant cell wall possesses the capacity togenerate ·OH in situ. Distinct POD and Mn-superoxidedismutase (Mn-SOD) isoforms different from other cellular isoformswere shown by native gel electropho-resis to be preferably boundto the cell walls. Electron paramagnetic resonance (EPR) spectroscopyof cell wall isolates containing the spin-trapping reagent,5-diethoxyphosphoryl-5-methyl-1-pyrroline-N-oxide (DEPMPO),was used for detection of and differentiation between ·OHand the superoxide radical (O2–·). The data obtainedusing POD inhibitors confirmed that tightly bound cell wallPODs are involved in DEPMPO/OH adduct formation. A decreasein DEPMPO/OH adduct formation in the presence of H2O2 scavengersdemonstrated that this hydroxyl radical was derived from H2O2.During the generation of ·OH, the concentration of quinhydronestructures (as detected by EPR spectroscopy) increased, suggestingthat the H2O2 required for the formation of ·OH in isolatedcell walls is produced during the reduction of O2 by hydroxycinnamicacids. Cell wall isolates in which the proteins have been denaturated(including the endogenous POD and SOD) did not produce ·OH.Addition of exogenous H2O2 again induced the production of ·OH,and these were shown to originate from the Fenton reaction withtightly bound metal ions. However, the appearance of the DEPMPO/OOHadduct could also be observed, due to the production of O2–·when endogenous SOD has been inactivated. Also, O2–·was converted to ·OH in an in vitro horseradish peroxidase(HRP)/H2O2 system to which exogenous SOD has been added. Takentogether with the discovery of the cell wall-bound Mn-SOD isoform,these results support the role of such a cell wall-bound SODin the formation of ·OH jointly with the cell wall-boundPOD. According to the above findings, it seems that the hydroxycinnamicacids from the cell wall, acting as reductants, contribute tothe formation of H2O2 in the presence of O2 in an autocatalyticmanner, and that POD and Mn-SOD coupled together generate ·OHfrom such H2O2. 相似文献
100.
Biljana ?. Gliši? 《Bioorganic chemistry》2010,38(4):144-10290
Proton NMR spectroscopy was applied to study the reactions of the dipeptides glycyl-glycine (Gly-Gly) and glycyl-l-alanine (Gly-l-Ala) with hydrogen tetrachloridoaurate(III) (H[AuCl4]). All reactions were performed at pH 2.0 and 3.0 and at 40 °C. The final products in these reactions were [Au(Gly-Gly-κ3NG1,NG2,OG2)Cl] and [Au(Gly-l-Ala-κ3NG,NA,OA)Cl] complexes. Tridentate coordination of the corresponding dipeptides and square-planar geometry of these Au(III) complexes was confirmed by NMR (1H and 13C) spectroscopy. This study showed that at pH < 3.0 the Au(III) ion was able to deprotonate the amide nitrogen atom. However this displacement reaction was very slow and the total concentration of the corresponding Au(III)-peptide complex formed after 5 days was less than 60% for the Gly-l-Ala or 70% for the Gly-Gly dipeptide. The kinetic data of the reactions between the Gly-Gly and Gly-l-Ala dipeptides and [AuCl4]− were compared with those for the histidine-containing Gly-l-His dipeptide. The differences in the reactivity of these three dipeptides with the Au(III) ion are discussed. 相似文献