J. A Driver

Bio: J. A Driver is an academic researcher. The author has contributed to research in topics: Medicine & Biology. The author has an hindex of 1, co-authored 1 publications receiving 667 citations.

Culture of endometrial epithelial cells collected by a cytological brush in vivo

Abstract: Graphical Abstract Summary: Understanding endometrial physiology in dairy cows is essential, as approximately 50% of pregnancies are lost in the first 3 weeks of gestation for unknown reasons. This work validated an approach to culture and propagate luminal endometrial cells harvest by a minimally invasive tool, endometrial cytology (cytobrush). (1) Cells were collected at a specific stage of the estrous cycle; (2) fresh cells were evaluated regarding their identity by immunofluorescence; and (3) functionality of the system was demonstrated by inducing transcription of IFN-stimulated genes (ISGs) in response to treatment with recombinant IFN-τ.

Thidiazuron: a potent cytokinin for woody plant tissue culture

Abstract: Thidizuron (TDZ) is among the most active cytokinin-like substances for woody plant tissue culture. It facilitates efficient micropropagation of many recalcitrant woody species. Low concentrations (<1 µM) can induce greater axillary proliferation than many other cytokinins; however, TDZ may inhibit shoot elongation. In some cases it is necessary to transfer shoots to an elongation medium containing a lower level of TDZ and/or a less active cytokinin. At concentrations higher than 1 µM, TDZ can stimulate the formation of callus, adventitious shoots or somatic embryos. Subsequent rooting of microshoots may be unaffected or slightly inhibited by prior exposure to TDZ. The main undesirable side effect of TDZ is that cultures of some species occasionally form fasciated shoots. The high cytokinin activity and positive response of woody species to TDZ have established it as among the most active cytokinins forin vitro manipulation of many woody species.

Agrobacterium-Mediated Transformation of Walnut Somatic Embryos and Regeneration of Transgenic Plants

Abstract: Genetically transformed walnut plants were regenerated from somatic embryos inoculated with a disarmed Agrobacterium tumefaciens strain containing a gene encoding kanamycin resistance. Embryo subclones derived from the inoculated embryos were selected for continued embryo proliferation on kanamycin-containing medium. Embryos and shoots were shown to contain and express the foreign gene and have been subjected to rooting procedures. Four rooted plantlets have been transplanted to soil and acclimatized. This is the first report of the successful transformation of a woody tree species from somatic embryos using Agrobacterium.

The dehydrogenase‐mediated recycling of NADPH is a key antioxidant system against salt‐induced oxidative stress in olive plants

Abstract: NADPH is an important molecule in the redox balance of the cell. In this paper, using olive tissue cultures as a model of the function of the NADPH-generating dehydrogenases in the mechanism of oxidative stress induced by severe salinity conditions was studied. When olive (Olea europaea) plants were grown with 200 mM NaCl, a 40% reduction in leaf fresh weight was produced. The content of non-enzymatic antioxidants such as ascorbate and glutathione was diminished between 20% to 39%, whereas the H2O2 content was increased threefold. In contrast, the analysis of the activity and protein contents of the main antioxidative enzymes showed a significant increase of catalase, superoxide dismutase and glutathione reductase. Overall, these changes strongly suggests that NaCl induces oxidative stress in olive plants. On the other hand, while the content of glucose-6-phosphate was increased almost eightfold in leaves of plants grown under salt stress, the content of NAD(P)H (reduced and oxided forms) did not show significant variations. Under salt stress conditions, the activity and protein contents of the main NADPH-recycling enzymes, glucose-6-phosphate dehydrogenase (G6PDH), isocitrate dehydrogenase (ICDH), malic enzyme (ME) and ferrodoxin-NADP reductase (FNR) showed an enhancement of 30-50%. In leaves of olive plants grown with 200 mM NaCl, analysis of G6PDH by immunocytochemistry and confocal laser scanning microscopy showed a general increase of this protein in epidermis, palisade and spongy mesophyll cells. These results indicate that in olive plants, salinity causes reactive oxygen species (ROS)-mediated oxidative stress, and plants respond to this situation by inducing different antioxidative enzymes, especially the NADPH-producing dehydrogenases in order to recycle NADPH necessary for the protection against oxidative damages. These NADP-dehydrogenases appear to be key antioxidative enzymes in olive plants under salt stress conditions.