Characterization of cry9Da4, cry9Eb2, and cry9Ee1 genes from Bacillus thuringiensis strain T03B001

Three cry9 genes, cry9Da4, cry9Eb2, and cry9Ee1, were cloned from Bacillus thuringiensis strain T03B001 using a high-resolution melting analysis method. All three cry9 genes were overexpressed in Escherichia coli Rosetta (DE3), and the expressed products Cry9Eb2 and Cry9Ee1 were shown to be toxic to Plutella xylostella and Ostrinia furnacalis, but not to Helicoverpa armigera or Colaphellus bowringi. The bioassay of Cry9Eb2 and Cry9Ee1 against Cry1Ac-resistant P. xylostella strains indicated that both novel Cry9 toxins exhibited no cross-resistance with Cry1Ac. Cry9Eb2 and Cry9Ee1 can be applied not only for P. xylostella and O. furnacalis control, but also for the Cry1Ac-resistance management of pests.     

Biopolymer microencapsulations of Bacillus thuringiensis crystal preparations for increased stability and resistance to environmental stress

Parasporal crystals synthesized by Bacillus thuringiensis (Bt) have been widely used as microbial pesticides because of their toxicity to the larval stages of specific insects. However, parasporal crystals can be damaged by environmental stresses, such as high temperature, ultraviolet radiation, and desiccation. To reduce environmental susceptibility of parasporal crystals and extend the duration of their activity, we developed a new type of protection by making microcapsules of crystals (MCs). The microcapsules were self-assembled by alternate deposition (layer by layer) of low-cost chitosan and sodium alginate (or sodium carboxymethyl cellulose) on the crystal surface. Crystal toxins (Cry1Ac) were released from microcapsules at pH values above 9.0. Bioassay results demonstrated that microencapsulated preparations had larvicidal toxicity equivalent to the non-encapsulated form. Microencapsuled crystals were protected from environmental stresses such as high temperature and desiccation. The results indicate that microcapsule protection can enhance the efficacy of Bt in pest control, especially to Lepidoptera larvae that have a alkaline midgut.

     

Aspirin promotes tenogenic differentiation of tendon stem cells and facilitates tendinopathy healing through regulating the GDF7/Smad1/5 signaling pathway

Tendinopathy is a common musculoskeletal system disorder in sports medicine, but regeneration ability of injury tendon is limited. Tendon stem cells (TSCs) have shown the definitive treatment evidence for tendinopathy and tendon injuries due to their tenogenesis capacity. Aspirin, as the representative of nonsteroidal anti-inflammatory drugs for its anti-inflammatory and analgestic actions, has been commonly used in treating tendinopathy in clinical, but the effect of aspirin on tenogenesis of TSCs is unclear. We hypothesized that aspirin could promote injury tendon healing through inducing TSCs tenogenesis. The aim of the present study is to make clear the effect of aspirin on TSC tenogenesis and tendon healing in tendinopathy, and thus provide new treatment evidence and strategy of aspirin for clinical practice. First, TSCs were treated with aspirin under tenogenic medium for 3, 7, and 14 days. Sirius Red staining was performed to observe the TSC differentiation. Furthermore, RNA sequencing was utilized to screen out different genes between the induction group and aspirin treatment group. Then, we identified the filtrated molecules and compared their effect on tenogenesis and related signaling pathway. At last, we constructed the tendinopathy model and compared biomechanical changes after aspirin intake. From the results, we found that aspirin promoted tenogenesis of TSCs. RNA sequencing showed that growth differentiation factor 6 (GDF6), GDF7, and GDF11 were upregulated in induction medium with the aspirin group compared with the induction medium group. GDF7 increased tenogenesis and activated Smad1/5 signaling. In addition, aspirin increased the expression of TNC, TNMD, and Scx and biomechanical properties of the injured tendon. In conclusion, aspirin promoted TSC tenogenesis and tendinopathy healing through GDF7/Smad1/5 signaling, and this provided new treatment evidence of aspirin for tendinopathy and tendon injuries.     

The absence of oestrogen receptor beta disturbs collagen I type deposition during Achilles tendon healing by regulating the IRF5‐CCL3 axis

Achilles tendon healing (ATH) remains an unanswered question in the field of sports medicine because it does not produce tissue with homology to the previously uninjured tissue. Oestrogen receptor β (ERβ) is involved in the injury and repair processes of tendons. Our previous study confirmed that ERβ plays a role in the early stage of ATH by affecting adipogenesis, but its role in extracellular matrix (ECM) remodelling is unknown. We established a 4‐week Achilles tendon repair model to investigate the mechanism through which ERβ affects ATH at the very beginning of ECM remodelling phase. In vitro studies were performed using tendon‐derived stem cells (TDSCs) due to their promising role in tendon healing. Behavioural and biomechanical tests revealed that ERβ‐deficient mice exhibit weaker mobility and inferior biomechanical properties, and immunofluorescence staining and qRT‐PCR showed that these mice exhibited an erroneous ECM composition, as mainly characterized by decreased collagen type I (Col I) deposition. The changes in gene expression profiles between ERβ‐knockout and WT mice at 1 week were analysed by RNA sequencing to identify factors affecting Col I deposition. The results highlighted the IRF5‐CCL3 axis, and this finding was verified with CCL3‐treated TDSCs. These findings revealed that ERβ regulates Col I deposition during ATH via the IRF5‐CCL3 axis.     

Bt蛋白Vip3Aa19、Cry1Ab和Cry1Ah对玉米蚜的效应评价

[目的] 探讨转基因玉米表达的3种Bt蛋白对非靶标害虫玉米蚜的影响效应,为农田生态系统中转基因玉米的环境安全评价提供依据。[方法] 在玉米蚜全纯人工饲料中分别添加Bt蛋白Vip3Aa19、Cry1Ab和Cry1Ah饲养玉米蚜,并以PBS缓冲液或Na₂CO₃溶液为阴性对照,添加酪蛋白（casein,CS）为中性对照,添加印楝素（neem oil）为阳性对照,比较分析Bt蛋白等各处理对玉米蚜存活率、发育历期、有翅蚜率及繁殖力的影响。[结果] 低浓度印楝素（Neem-L）处理后玉米蚜半数个体生存时间（ST₅₀）为3.2~4.0 d,高浓度印楝素（Neem-H）处理后,玉米蚜在第4天全部死亡,这2个处理均没有子代若蚜产生。添加Bt蛋白和CS对玉米蚜的生存时间没有显著影响,ST₅₀在8.3~9.6 d之间。与阴性对照相比,3个Bt蛋白和CS处理的若蚜期显著短1.0~2.9 d,产出的下一代若蚜数显著增多。Vip3Aa19、Cry1Ab以及CS处理后,有翅蚜比例显著高于其阴性对照。[结论] 饲料中分别添加3种Bt蛋白Vip3Aa19、Cry1Ab和Cry1Ah对玉米蚜的存活率没有显著影响,但具有与添加CS等同提高饲料营养质量的效果;与阴性对照相比,添加3种Bt蛋白对玉米蚜的生长发育和繁殖具有显著的促进效应。     

Evaluation of transgenic Bt corn for resistance to the Asian corn borer (Lepidoptera: Pyralidae)

The Asian corn borer, Ostrinia furnacalis (Guenée), is the most important insect pest on corn in China. Bt transgenic corn provides a new tool for Asian corn borer control. Monsanto's YieldGard Bt transgenic corn expressing Cry1Ab protein, and a non-Bt control, were evaluated in Beijing. Laboratory bioassays were carried out by exposing neonates to an agar-free diet containing Bt corn whorl leaves, tassels, and anthers, or by exposing neonates directly to fresh silk and pollen. These are the tissues initially attacked by neonates in the field. All of these tissues, with the exception of pollen, contained sufficient insecticidal protein to kill > or = 95% of larvae within 7 d. Surviving larvae had also not grown beyond first instar and weighed < or = 0.1 mg. Although larvae feeding on Bt corn pollen were significantly smaller than those on non-Bt corn pollen, there was no significant difference in mortality. Field trials were also conducted with artificial infestations of Asian corn borer at mid whorl, late whorl, and silking stages. Damage ratings and number of larvae surviving per plant indicated that Bt corn was highly resistant to Asian corn borer. Therefore, YieldGard offers the potential for season-long protection against first- and second-generation Asian corn borer.