Aroma serves as one of the decisive factors influencing the value of banana commodities. Most of characteristic volatile organic components (VOCs) are formed during post-harvesting. However, the changing of VOCs of banana at different post-harvesting stages remain ambiguous. In this study, the VOCs of Cavendish banana for the four typical post-harvesting stages (green stage/half of yellow stage/yellow ripening stage/over ripening stage) are clarified using headspace solid phase micro-extraction (HS-SPME), combined with gas chromatography-mass spectrometry (GC–MS). The results inferred that the relative content of branched-chain esters such as acetate and butyrate, which form the main contributors of aroma in bananas, is higher in the T2 and T3 stages. Further, RNA-Seq technology was employed to clarify the formation mechanism of banana aroma in the post-harvesting stage. The MaTGL4 gene of the linoleic acid metabolism pathway and the MaBCAT3 and MaBCAT5 genes of the valine, leucine and isoleucine degradation pathway in banana suggest the expression is active late in the ripening stage, and the upregulated expression of these genes is analogous to the formation of aroma components such as branched-chain esters and hexenal. The above results not only provide baseline data on the differences in physical and chemical properties of VOCs in various post-harvesting stages of banana production, but also provide theoretical guidance facilitating the subsequent improvement of the commercial value of bananas through genetic improvement.
Noninvasive visualization of embryos at different development stages is crucial for the understanding of the basic developmental biology. It is therefore desirable to have an imaging tool capable of rapidly evaluating the effects of gene manipulation or genome editing in developing embryos for the studies of gene functions and genetic engineering. Here, we propose and demonstrate a novel use of optical coherence tomography (OCT) to noninvasively exam the embryonic development of the migratory locusts in real time with 3‐dimensional (3D) view capability. In particular, we obtain the sufficiently high spatial resolution tomographic 2D and 3D images of live locust embryos throughout their development processes. We show that not only we are able to noninvasively observe all previously known forms of blastokinesis as an embryo develops, such as anatrepsis, katatrepsis, revolution, rotation and diapauses, and determine their precise occurring time or duration, but also discover an unreported rotation form we named “twist.” In addition, with the OCT images we determined the exact occurring time of diapauses of the locusts from Tibetan plateau for the first time. Finally, we demonstrate that OCT systems can be used to rapidly capture the development defects of genetically modified embryos in which certain genes essential for embryonic development were suppressed by RNA interference. Our work shows that OCT is an enabling imaging tool with sufficient spatial resolution for the rapid evaluation of embryonic variations of small animals. 相似文献
溴结构域和超末端结构域(bromodomain and extraterminal domain, Bet)家族是表观基因组的调节因子,也是肿瘤细胞生存所依赖的肿瘤相关基因表达的关键驱动因子。溴结构域蛋白4 (bromodomain-containing protein 4, Brd4)是溴域和端外蛋白家族中的一员,通常识别乙酰化组蛋白,并定位于目的基因的启动子或增强子区域,启动并维持肿瘤相关基因的表达。Brd4与多种转录因子调控和染色质修饰密切相关,并参与DNA损伤修复、维持端粒功能,从而维持肿瘤细胞的存活。本文围绕Brd4蛋白的结构、功能及其抑制剂在肿瘤研究中的应用进行综述。 相似文献
Transgenic techniques in chickens have been developed much more slowly than in mammals due to chickens’ unique reproduction mechanism. Retroviral methods have been the most successful. piggyBac (PB) is a transposon that has a 13 bp perfect terminal invert repeat sequence. PB can be inserted into TTAA sites and can also be precisely excised in mammals. Therefore, we have selected PB as a candidate to establish a new method to produce transgenic chickens. We constructed three donor vectors (ZGl-neo, ZGm-neo and ZGs-neo) expressing a GFP marker-gene and a neomycin resistant gene based on PB. We co-transfected each donor vector with a helper vector (CAG-PBase). We found that ZGl-neo was the most efficient PB vector. This vector could insert into TTAA sites in DF-1 cells. PB vectors were microinjected into sub-germinal cavity of newly laid eggs, and electroporation was then performed with a 20-V pulse for 5 cycles of 50 ms on and 100 ms off. GFP was expressed in different tissues of the embryos, including the gonads. Twenty-two chickens hatched after microinjection with compounds ZGl-neo and CAG-PBase (3:1). When we screened the blood DNA, 73 % (16/22) of the individuals were positive. Thirteen of the chickens grew to adulthood, 11 of which were males. 40 % (4/10) of the individuals were semen positive, and their copy numbers ranged from 0.05 to 0.21 (0.11, 0.21, 0.05, 0.06). No G1 offspring containing the integrated transposon were produced. We conclude that the PB transposon system is a novel useful tool for the efficient production of transgenic chickens. 相似文献
Osteoarthritis (OA) is one of the most prevalent joint diseases in aged people and characterized by articular cartilage degeneration, synovial inflammation, and abnormal bone remodeling. Recent advances in OA research have clearly shown that OA development is associated with aberrant DNA methylation status of many OA-related genes. As one of most important cartilage degrading proteases in OA, a disintegrin and metalloproteinase with thrombospondin motifs subtype 5 (ADAMTS-5) is activated to mediate cartilage degradation in human OA and experimental murine OA models. The pathological factors and signaling pathways mediating ADAMTS-5 activation during OA development are not well defined and have been a focus of intense research. ADAMTS-5 promoter is featured by CpG islands. So far there have been no reports concerning the DNA methylation status in ADAMTS-5 promoter during OA development. In this study, we sought to investigate DNA methylation status in ADAMTS-5 promoter, the role of DNA methylation in ADAMTS-5 activation in OA, and the underlying mechanisms. The potential for anti-OA intervention therapy which is based on modulating DNA methylation is also explored. Our results showed that DNA methyltransferases 1 (Dnmt1) downregulation-associated ADAMTS-5 promoter demethylation played an important role in ADAMTS-5 activation in OA, which facilitated SPI-1 binding on ADAMTS-5 promoter to activate ADAMTS-5 expression. More importantly, OA pathological phenotype of mice was alleviated in response to Dnmt1-induced DNA methylation of ADAMTS-5 promoter. Our study will benefit not only for deeper insights into the functional role and regulation mechanisms of ADAMTS-5 in OA, but also for the discovery of disease-modifying OA drugs on the basis of ADAMTS-5 via modulating DNA methylation status. 相似文献