In most experimental animals, it is challenging to combine mutations and rescue transgenes and to use bipartite systems to assess gene expression. To circumvent the difficulties in combining multiple genetic elements, we developed the DREaMR (Drug-on, REporter, Mutant, Rescue) system. Using Drosophila white as the initial model, we demonstrated that introduction of a single insertion by CRISPR/Cas9 created a null mutation, a tagged rescue construct, which could be induced with doxycycline, and which allowed assessment of protein expression. To create a DREaMR in an organism in which combining multiple genetic elements is more problematic than in Drosophila, we tested the mosquito, Aedes aegypti—the insect vector for dengue, yellow fever, Zika, and other viral diseases. We generated a DREaMR allele in the kh gene, which permitted us to induce expression of the rescue construct, and detect expression of Kh. Thus, this system avoids the need to perform genetic crosses to introduce an inducible rescue transgene in a mutant background, or to combine driver and reporter lines to examine expression of the targeted protein. We propose that DREaMR provides a system that can be applied to additional mosquito vectors as well as other organisms in which CRISPR/Cas9 is effective. 相似文献
Salt stress and alkali stress are major factors that affect the growth and production of Chinese cabbage. To explore their tolerant mechanism to salt and alkali stress, three salinity levels (0, 50, 100 mmol/L NaCl) and three different pH levels (pH6.5, pH7.5, pH8.5) were interactively applied on Qinghua (salt-tolerant–alkali-sensitive) and Biyu (salt-sensitive–alkali-tolerant) cultivars; the root morphology, ion content and antioxidant enzymes were determined. The results showed that the root morphology and root water content of Qinghua under S0pH7.5 and S0pH8.5 were seriously affected, and the content of H2O2 and MDA increased by 143%, 190% and 234%, 294%, respectively, compared with S0pH6.5; when Biyu was under S50pH6.5 and S100pH6.5 stress, the content of H2O2 and MDA increase to 152%, 208% and to 240%, 263%, respectively, but the activities and genes expression of SOD, POD, CAT, AAO, APX, DHAR and MDHAR did not change. The root and the contents of H2O2 and MDA were not affected when Qinghua was treated with salt and Biyu was treated with alkali, but the activities of the antioxidant enzymes increased to 150–200%, and their relative expression was overexpressed and 2.5–3.5-fold of the S0pH6.5. The increase of Na+ in Qinghua was limited under salt stress, Mg2+ in Biyu increased significantly under alkali stress. These all indicated that the adaptability of roots could reflect the degree of tolerance; Chinese cabbage with high salt and alkali tolerance enhanced the regulation of their absorption of ions and increased the relative expression and activities of related antioxidant enzymes.
Two uncharged (99m)Tc-labeled phenylbenzoxazole derivatives were biologically evaluated as potential imaging probes for β-amyloid plaques. The (99m)Tc and corresponding rhenium complexes were synthesized by coupling monoamine-monoamide dithiol (MAMA) and bis(aminoethanethiol) (BAT) chelating ligand via a pentyloxy spacer to phenylbenzoxazole. The fluorescent rhenium complexes 6 and 9 selectively stainined the β-amyloid plaques on the sections of transgenic mouse, and showed high affinity for Aβ((1-42)) aggregates (K(i)=11.1 nM and 14.3 nM, respectively). Autoradiography in vitro indicated that [(99m)Tc]6 clearly labeled β-amyloid plaques on the sections of transgenic mouse. Biodistribution experiments in normal mice revealed that [(99m)Tc]6 displayed moderate initial brain uptake (0.81% ID/g at 2 min), and quickly washed out from the brain (0.25% ID/g at 60 min). The preliminary results indicate that the properties of [(99m)Tc]6 are promising, although additional refinements are needed to improve the ability to cross the blood-brain barrier. 相似文献
Clinical studies suggest that aneurysm aspect ratio (AR) is an important indicator of rupture likelihood. The importance of AR is hypothesized to arise from its influence on intra-aneurysmal hemodynamics. It has been conjectured that slower flow in high AR sacs leads to a cascade of biological activities that weaken the aneurysm wall (Ujiie et al.,1999). However, the connection between AR, hemodynamics and wall weakening has never been proven. Animal models of saccular aneurysms provide a venue for evaluating this conjecture. The focus of this work was to evaluate whether a commonly used elastase induced aneurysm model in rabbits is suitable for a study of this kind from a hemodynamic perspective. In particular, to assess whether hemodynamic factors in low and high AR sacs are statistically different. To achieve this objective, saccular aneurysms were created in 51 rabbits and pulsatile computational fluid dynamics (CFD) studies were performed using rabbit specific inflows. Distinct hemodynamics were found in the low AR (AR<1.8, n=25), and high AR (AR>2.2, n=18) models. A single, stable recirculation zone was present in all low AR aneurysms, whereas a second, transient recirculation zone was also found in the superior aspect of the aneurysm dome for all high AR cases. Aneurysms with AR between 1.8 and 2.2 displayed transitional flow patterns. Differences in values and distributions of hemodynamic parameters were found between low and high AR cases including time averaged wall shear stress, oscillatory shear index, relative residence time and non-dimensional inflow rate. This work lays the foundation for future studies of the dependence of growth and remodeling on AR in the rabbit model and provides a motivation for further studies of the coupling between AR and hemodynamics in human aneurysms. 相似文献
Cordyceps is a rare and exotic mushroom that grows out of the head of a mummified caterpillar. Many companies are cultivating Cordyceps to meet the increased demand for its medicinal applications. However, the structures and functions of polysaccharides, one of the pharmaceutical active ingredients in Cordyceps, are difficult to reproduce in vitro. We hypothesized that mimicking the salty environment inside caterpillar bodies might make the cultured fungus synthesize polysaccharides with similar structures and functions to that of wild Cordyceps. By adding either sodium sulfate or sodium chloride into growth media, we observed the salinity-induced anti-angiogenesis activities of the polysaccharides purified from the cultured C. Militaris. To correlate the activities with the polysaccharide structures, we performed the 13C-NMR analysis and observed profound structural changes including different proportions of α and β glycosidic bonds and appearances of uronic acid signals in the polysaccharides purified from the culture after the salts were added. By coupling the techniques of stable 34S-sulfate isotope labeling, aniline- and D5-aniline tagging, and stable isotope facilitated uronic acid-reduction with LC-MS analysis, our data revealed for the first time the existence of covalently linked sulfate and the presence of polygalacuronic acids in the polysaccharides purified from the salt added C. Militaris culture. Our data showed that culturing C. Militaris with added salts changed the biosynthetic scheme and resulted in novel polysaccharide structures and functions. These findings might be insightful in terms of how to make C. Militaris cultures to reach or to exceed the potency of wild Cordyceps in future. 相似文献