Bt rice could provide ecological resistance against nontarget planthoppers

Genetically engineered (GE) rice lines expressing Lepidoptera‐active insecticidal cry genes from the bacterium Bacillus thuringiensis (Bt) have been developed in China. Field surveys indicated that Bt rice harbours fewer rice planthoppers than non‐Bt rice although planthoppers are not sensitive to the produced Bt Cry proteins. The mechanisms underlying this phenomenon remain unknown. Here, we show that the low numbers of planthoppers on Bt rice are associated with reduced caterpillar damage. In laboratory and field‐cage experiments, the rice planthopper Nilapavata lugens had no feeding preference for undamaged Bt or non‐Bt plants but exhibited a strong preference for caterpillar‐damaged plants whether Bt or non‐Bt. Under open‐field conditions, rice planthoppers were more abundant on caterpillar‐damaged non‐Bt rice than on neighbouring healthy Bt rice. GC–MS analyses showed that caterpillar damage induced the release of rice plant volatiles known to be attractive to planthoppers, and metabolome analyses revealed increased amino acid contents and reduced sterol contents known to benefit planthopper development. That Lepidoptera‐resistant Bt rice is less attractive to this important nontarget pest in the field is therefore a first example of ecological resistance of Bt plants to nontarget pests. Our findings suggest that non‐Bt rice refuges established for delaying the development of Bt resistance may also act as a trap crop for N. lugens and possibly other planthoppers.     

遮荫对3年生东北铁线莲生长特性及品质的影响

采用人工遮荫的方法,研究了遮荫处理(全光照CK、遮荫30%、50%、70%和90%)对东北铁线莲生长特性和品质的影响。结果表明:东北铁线莲株高随着遮荫梯度的增加而增高;30%遮荫处理茎粗最粗,根茎生物最高,与其它处理差异显著;而茎生物量、叶生物量则是30%遮荫处理与CK、70%和90%处理差异显著;东北铁线莲各器官生物量对光照强度的响应不同,表现为根茎生物量比、根冠比随着光照强度的减弱而降低,茎生物量比和叶生物量比则随着光照的减弱而增加,说明在遮荫的条件下,东北铁线莲优先将生物量分配给茎和叶,用来增加叶面积,以便于接受更多的光能,维持自身的生长发育。东北铁线莲光合色素含量随着遮荫梯度的增加而增加,90%遮荫下的东北铁线莲叶片光合色素含量最高,与其他处理差异显著;相反叶绿素a/b的值却最低;尤其是3年生东北铁线莲叶片中叶绿素 b含量随着光照强度的减弱而升高,能够使东北铁线莲充分吸收散射光,保持较强的光合能力。30%遮荫处理东北铁线莲净光合速率为10.86 μmol · m^-2 · s^-1,显著高于其它处理;随着光照强度的减弱东北铁线莲Gs先增加后降低,Ci则是先降低后增加,30%遮荫处理与其它处理间差异显著,但随着遮荫梯度的增加,东北铁线莲的净光合速率降低,光合作用合成产物总量减少,导致70%和90%遮荫条件下生物量较低;遮荫不利于东北铁线莲有效成分齐墩果酸的积累,不同处理,东北铁线莲齐墩果酸含量差异较大,以全光照和30%遮荫处理齐墩果酸含量较高,与其它处理间差异显著。因此,在生产实践上,对其进行适度遮荫,既保证东北铁线莲药材的质量,又提高药材产量;同时,若不以采收种子为目的,建议在8月份以后采收东北铁线莲药材。     

黄瓜卷须缠绕过程中小G蛋白活性变化

攀爬植物的卷须是对机械刺激极为敏感的器官。拟南芥(Arabidopsisthaliana)小G蛋白能够响应机械刺激调控自身发育,但小G蛋白信号是否在卷须感受机械刺激发生缠绕过程中发挥作用目前尚不清楚。该研究以黄瓜(Cucumissativus)为实验材料,对其卷须受机械刺激缠绕过程中小G蛋白活性进行了探讨。ROP活性检测结果表明,在卷须缠绕过程中小G蛋白CsROP6的活性显著增强;同时,质谱鉴定结果显示,卷须缠绕过程中生长素的含量明显增加。进一步的实验表明,外源生长素处理能明显增强CsROP6的活性,暗示黄瓜卷须在缠绕过程中受机械刺激可能通过生长素增强ROP活性,且机械刺激激活小G蛋白信号在不同植物中存在一定的保守性。     

RP105 involved in activation of mouse macrophages via TLR2 and TLR4 signaling

RP105 is a member of the toll-like receptor family of proteins that transmits an activation signal in B cells, playing a role in regulation of B cell growth and death; in macrophages and dendritic cells, RP105 is a specific inhibitor of TLR4 signaling. RP105 is uniquely important for regulating TLR4-dependent signaling. It also proved that RP105 is closely related to TLR2 in macrophage activation by Mycobacterium tuberculosis lipoproteins. The aim of our study is to investigate the role of RP105 in mouse macrophages activation of TLR4 and TLR2 signaling by lipopolysaccharides (LPS) and Pam3CysSerLys4 (Pam3CSK4) alone or in combination, and the interaction between TLR2 and TLR4 signaling through RP105. Our results indicate that besides exhibiting negative regulation of TNF-α and IL12-p40 secretion in macrophage activated by LPS, RP105 is also involved in macrophages activation by Pam3CSK4 through TLR2 signaling and exhibited regulation to IL-10 and RANTES production by mouse peritoneal macrophage activated by Pam3CSK4. In macrophages activation by LPS and Pam3CSK4 in combination, TLR2 signaling can overcome RP105-mediated regulation of TLR4 signaling. Thus, our data demonstrate that not only TLR4 signaling, but also RP105 appears to be an essential accessory for immune responses through TLR2 signaling. The function of TLR2 and TLR4 in response to TLR ligands could be associated with each other by RP105. These results can help us understanding the unique role of RP105 in macrophages response to TLR ligands.     

Seasonal expression of Bt proteins in transgenic rice lines and the resistance against Asiatic rice borer Chilo suppressalis (Walker)

Laboratory bioassays and field surveys were carried out to compare the resistance of three transgenic rice (Oryza sativa L.) lines including Bt-DL expressing a single gene cry1Ab, Bt-KF6 expressing stacked genes cry1Ac and CpTI genes and Bt-SY63 expressing a fusion gene cry1Ab/cry1Ac, respectively, to an important rice pest Chilo suppressalis (Walker). In addition, enzyme-linked immunosorbent assays (ELISA) were conducted to monitor the Bt protein expressions in rice leaves and stems at different rice growth stages. Results showed that all the transgenic rice lines exhibited significantly high resistance to the pest compared with their corresponding nontransformed isolines. Among the transgenic rice lines, Bt-SY63 and Bt-KF6 had higher resistance to C. suppressalis at early growth stage, but lower resistance at late stages, while the pest resistance of Bt-DL was relatively stable throughout the growing season. The results were consistent with ELISA results showing that Bt protein levels in Bt-SY63 or Bt-KF6 leaves decreased in late growth stages, but were relatively stable in Bt-DL at all growth stages. This demonstrates that the resistance to a pest by Bt plants is positively correlated with Cry protein expression levels in plant tissues. Compared with Bt-SY63 and Bt-KF6, the Bt protein expression levels were significantly lower in Bt-DL, while its resistance to C. suppressalis was the highest. This may suggest that C. suppressalis is more susceptible to Cry1Ab than to Cry1Ac. The data from the current study are valuable for decision-making for commercial use of Bt rice lines and development of appropriate pest control and resistance management strategies for the transgenic rice lines.     

Cyanidin-3-O-β-glucoside inhibits lipopolysaccharide-induced inflammatory response in mouse mastitis model

Cyanidin-3-O-β-glucoside (C3G) (CAS number 7084-24-4), a typical anthocyanin pigment that exists in the human diet, has been reported to have anti-inflammatory properties. However, the effect of C3G on lipopolysaccharide (LPS)-induced mastitis and the molecular mechanisms have not been investigated. In this study, we detected the protective effects of C3G on a LPS-induced mouse mastitis model and investigated the molecular mechanisms in LPS-stimulated mouse mammary epithelial cells (MMECs). Our results showed that C3G could attenuate mammary histopathologic changes and myeloperoxidase activity, and inhibit TNF-α, interleukin (IL)-1β, and IL-6 production caused by LPS. Meanwhile, C3G dose-dependently inhibited TNF-α and IL-6 in LPS-stimulated MMECs. C3G suppressed LPS-induced nuclear factor-κB (NF-κB) and interferon regulatory factor 3 (IRF3) activation. Furthermore, C3G disrupted the formation of lipid rafts by depleting cholesterol. Moreover, C3G activated liver X receptor (LXR)-ABCG1-dependent cholesterol efflux. Knockdown of LXRα abrogated the anti-inflammatory effects of C3G. In conclusion, C3G has a protective effect on LPS-induced mastitis. The promising anti-inflammatory mechanisms of C3G are associated with upregulation of the LXRα-ABCG1 pathway which result in disrupting lipid rafts by depleting cholesterol, thereby suppressing toll-like receptor 4-mediated NF-κB and IRF3 signaling pathways induced by LPS.     

Identification of metabolism-associated molecular subtype in ovarian cancer

Ovarian cancer (OC) is the most lethal gynaecological cancer with genomic complexity and extensive heterogeneity. This study aimed to characterize the molecular features of OC based on the gene expression profile of 2752 previously characterized metabolism-relevant genes and provide new strategies to improve the clinical status of patients with OC. Finally, three molecular subtypes (C1, C2 and C3) were identified. The C2 subtype displayed the worst prognosis, upregulated immune-cell infiltration status and expression level of immune checkpoint genes, lower burden of copy number gains and losses and suboptimal response to targeted drug bevacizumab. The C1 subtype showed downregulated immune-cell infiltration status and expression level of immune checkpoint genes, the lowest incidence of BRCA mutation and optimal response to targeted drug bevacizumab. The C3 subtype had an intermediate immune status, the highest incidence of BRCA mutation and a secondary optimal response to bevacizumab. Gene signatures of C1 and C2 subtypes with an opposite expression level were mainly enriched in proteolysis and immune-related biological process. The C3 subtype was mainly enriched in the T cell-related biological process. The prognostic and immune status of subtypes were validated in the Gene Expression Omnibus (GEO) dataset, which was predicted with a 45-gene classifier. These findings might improve the understanding of the diversity and therapeutic strategies for OC.     

短期增温对西藏念青唐古拉山典型植物群落结构和稳定性的影响

青藏高原气候变暖幅度显著高于全球其他区域,深刻影响着该地区植物群落的结构和稳定性。选择西藏念青唐古拉山的三种典型植物群落(高寒草原、高寒草甸和流石滩)作为研究对象,采用开顶式增温箱(OTC)模拟增温,研究了短期增温对植物群落结构和稳定性的影响。结果表明:(1)增温改变了群落的优势物种,影响其结构组成,而对物种多样性无显著影响;(2)增温显著降低了高寒草甸的地上生物量(P < 0.05),增加地下生物量(P < 0.01),从而导致了群落地下地上生物量分配策略的改变;(3)增温降低群落中部分物种的生态位宽度,进而影响群落稳定性,其中高寒草甸变化最大,达到-66.8%。研究结果可为青藏高原高寒草地生态系统应对和适应未来气候变化提供一定科学依据。