A novel series of fluorinated 2-phenylindole derivatives were synthesized and evaluated as β-amyloid imaging probes for PET. The in vitro inhibition assay demonstrated that their binding affinities for Aβ1–42 aggregates ranged from 28.4 to 1097.8 nM. One ligand was labeled with 18F ([18F]1a) for its high affinity (Ki = 28.4 nM), which was also confirmed by in vitro autoradiography experiments on brain sections of transgenic mouse (C57BL6, APPswe/PSEN1, 11 months old, male). In vivo biodistribution experiments in normal mice showed that this radiotracer displayed high initial uptake (5.82 ± 0.51% ID/g at 2 min) into and moderate washout (2.77 ± 0.31% ID/g at 60 min) from the brain. [18F]1a could be developed as a promising new PET imaging probe for Aβ plaques although necessary modifications are still needed. 相似文献
The transgenic Bt cotton plant has been widely planted throughout the world for the control of cotton budworm Helicoverpa armigera (Hubner). However, a shift towards insect tolerance of Bt cotton is now apparent. In this study, the gene encoding neuropeptide F (NPF) was cloned from cotton budworm H. armigera, an important agricultural pest. The npf gene produces two splicing mRNA variants—npf1 and npf2 (with a 120‐bp segment inserted into the npf1 sequence). These are predicted to form the mature NPF1 and NPF2 peptides, and they were found to regulate feeding behaviour. Knock down of larval npf with dsNPF in vitro resulted in decreases of food consumption and body weight, and dsNPF also caused a decrease of glycogen and an increase of trehalose. Moreover, we produced transgenic tobacco plants transiently expressing dsNPF and transgenic cotton plants with stably expressed dsNPF. Results showed that H. armigera larvae fed on these transgenic plants or leaves had lower food consumption, body size and body weight compared to controls. These results indicate that NPF is important in the control of feeding of H. armigera and valuable for production of potential transgenic cotton. 相似文献
Plant stature is one important factor that affects the productivity of peach orchards. However, little is known about the molecular mechanism(s) underlying the dwarf phenotype of peach tree. Here, we report a dwarfing mechanism in the peach cv. FenHuaShouXingTao (FHSXT). The dwarf phenotype of ‘FHSXT’ was caused by shorter cell length compared to the standard cv. QiuMiHong (QMH). ‘FHSXT’ contained higher endogenous GA levels than did ‘QMH’ and did not response to exogenous GA treatment (internode elongation). These results indicated that ‘FHSXT’ is a GA‐insensitive dwarf mutant. A dwarf phenotype‐related single nucleotide mutation in the gibberellic acid receptor GID1 was identified in ‘FHSXT’ (GID1cS191F), which was also cosegregated with dwarf phenotype in 30 tested cultivars. GID1cS191F was unable to interact with the growth‐repressor DELLA1 even in the presence of GA. ‘FHSXT’ accumulated a higher level of DELLA1, the degradation of which is normally induced by its interaction with GID1. The DELLA1 protein level was almost undetectable in ‘QMH’, but not reduced in ‘FHSXT’ after GA3 treatment. Our results suggested that a nonsynonymous single nucleotide mutation in GID1c disrupts its interaction with DELLA1 resulting in a GA‐insensitive dwarf phenotype in peach. 相似文献
Although
green light is not considered to contribute to the photosynthesis of plants, the photosynthesis of ginger, a dual-purpose vegetable used as a medicine and food, is affected by the green wave band. In this study, the supplementary green band of sunlight (SG) increased the net photosynthetic rate (Pn), maximal photochemical efficiency of PSII (Fv/Fm), and actual photochemical efficiency of PSII (Y(II)) compared with the sunlight treatment (S). The Pn and Fv/Fm of the SG treatment were higher than those of the white light (W) treatment, while the Pn and Fv/Fm of the green light (G) treatment alone were lower than those of the W treatment. Further analysis found that the minimal fluorescence (Fo) of the S treatment increased, especially at noon, while the Fo of the SG treatment decreased. Similarly, the Fo of the W treatment increased significantly, while the Fo of the white–green mixed light (WG) treatment decreased. The relative fluorescence values of the K-J-I bands in the SG and WG treatments were lower than those in the S and W treatments, respectively. The photochemical quenching (qP) of the WG treatment was higher than that of the W treatment, while the primary thermal losses corresponded to the sum of nonregulated heat dissipation and fluorescence emission (Y(NO)) of the WG treatment was lower than that of the W treatment. The SG treatment reduced the accumulation of plastoglobules but increased the accumulation of starch granules and leaf thickness. Moreover, the green band supplemented with white light significantly increased the biomass of the aboveground plant parts and promoted the active growth of the aboveground parts. Supplementing green light plays a regulatory role in ginger based on the following four points. First, it effectively promotes the transfer of electrons between the acceptor side of photosystem II; second, it optimizes ginger photosynthesis; third, it alleviates strong light stress by reducing the accumulation of reactive oxygen species; and fourth, it promotes heat dissipation and reduces the rapid burst of active oxygen in the chloroplast caused by excess energy. In summary, green light can significantly optimize the photosynthetic characteristics of ginger.
Based on the conjugate strategy, two neutral 99mTc labeled 2-(1-(6-(dialkylamino)naphthalen-2-yl)ethylidene)malononitrile (DDNP) and 1-(6-(dialkylamino)naphthalen-2-yl)ethanone (ENE) derivatives, and their corresponding rhenium complexes were synthesized. In vitro fluorescent staining indicated that the corresponding rhenium derivatives selectively stained the β-amyloid (Aβ) plaques in the brain sections of AD model mice with low background. Compared with FDDNP and FENE, the affinities of the corresponding rhenium derivatives to Aβ aggregates decreased about 10-14-fold. In vivo biodistribution experiments in normal mice showed that 99mTc-MAMA-ENE displayed medium initial brain uptake (0.65 %ID/g at 2 min) with a reasonable washout from the brain (0.19 %ID/g at 2 h) while 99mTc-MAMA-DDNP showed a low brain uptake (0.28 %ID/g at 2 min). Further optimize these 99mTc-labeled tracers in order to improve their binding affinities to Aβ plaques and diffusion through the blood brain barrier may generate useful imaging agents for SPECT. 相似文献