柑橘凤蝶蛹发声器的显微结构及防御作用(英文)

【目的】动物界存在多种用于对抗捕食者的防御机制。一些鳞翅目昆虫的蛹在受到机械刺激时会发出蠕动的声音。【方法】在扫描电镜下对柑橘凤蝶Papilio xuthus蛹的发声器形态特征进行观察,并使用Audacity软件对捕获的声音进行特征分析。【结果】柑橘凤蝶蛹在腹部第4-5节和第5-6节之间的节间膜上存在发声器,有规律地发出嘶嘶声。发声器由多层甲壳素构成的刮器和板组成,刮器和板上有 50~90个突起。当蛹的腹部被寄生蜂触角刺激30 s以上时,刮器和板会迅速相互摩擦,腹部反复摆动发出声音。蛹发出的声音是由一系列每2 000~3 000 ms发生3次的短脉冲组成的。频带很宽,主要分布在5~20kHz范围内。新鲜蛹和越冬蛹的活性不同,声强也不同。【结论】本研究首先描述了柑橘蝴蝶蛹发声器的结构,结果支持了一些蝴蝶蛹对寄生生物进化出一种特殊的防御机制(声学防御)的假说。此外,通过比较两种生境的柑橘凤蝶蛹的声波特征,我们提出了同一物种在不同地理区域可以产生方言的假说。 关键词:     

EphA4 Obstructs Spinal Cord Neuron Regeneration by Promoting Excessive Activation of Astrocytes

Cellular and Molecular Neurobiology - Studies have found that molecular targets that regulate tissue development are also involved in regulating tissue regeneration. Erythropoietin-producing...     

PIK3CA hotspot mutations p. H1047R and p. H1047L sensitize breast cancer cells to thymoquinone treatment by regulating the PI3K/Akt1 pathway

Background

Nigella sativa (N. sativa) exhibits anti-inflammatory, antioxidant, antidiabetic, antimetastatic and antinociceptive effects and has been used to treat dozens of diseases. Thymoquinone (TQ) is an important and active component isolated from N. sativa seeds. Inhibition of cancer-associated activating PIK3CA mutations is a new prospective targeted therapy in personalized metastatic breast cancer (MBC). TQ is reported to be an effective inhibitor of the PI3K/Akt1 pathway in MBC. This study aimed to evaluate the in vitro antitumor effect of TQ in the context of two PIK3CA hotspot mutations, p. H1047R and p. H1047L.

Methods and results

Molecular dynamics, free energy landscapes and principal component analyses were also used to survey the mechanistic effects of the p. H1047R and p. H1047L mutations on the PI3K/Akt1 pathway. Our findings clearly confirmed that the p. H1047R and p. H1047L mutants could reduce the inhibitory effect of ΔNp63α on the kinase domain of PIK3CA, resulting in increased activity of PI3K downstream signals. Structurally, the partial disruption of the interaction between the ΔNp63α DNA binding domain and the PIK3CA kinase domain at residues 114–359 and 797–1068 destabilizes the conformation of the activation loop and modifies the PIK3CA/ΔNp63α complex. Alongside these structural changes, we found that TQ treatment resulted in high PI3K/Akt1 pathway inhibition in p. H1047R and p. H1047L-expressing cells versus wild-type cells.

Conclusions

These two PIK3CA hotspot mutations therefore not only contribute to tumor progression in patients with MBC but may also serve as targets for the development of novel small molecule therapeutic strategies.

     

Bak interacts with AKT and is involved in TNFα/CHX-induced apoptosis

Molecular and Cellular Biochemistry - Bak is important for TNFα/CHX-induced neuronal death, but the precise molecular mechanism remains unclear. At the same time, TNFα/CHX concomitantly...     

Comprehensive binary interaction mapping of τ phosphotyrosine sites with SH2 domains in the human genome: Implications for the rational design of self-inhibitory phosphopeptides to target τ hyperphosphorylation signaling in Alzheimer’s Disease

Amino Acids - Human microtubule-associated protein Tau (τ) is abundant in the axons of neurons where it stabilizes microtubule bundles; abnormally hyperphosphorylated τ is a hallmark of...     

Uncoupling protein 1 knockout aggravates isoproterenol-induced acute myocardial ischemia via AMPK/mTOR/PPARα pathways in rats

Transgenic Research - Uncoupling protein 1 (UCP1) was found exclusively in the inner membranes of the mitochondria of brown adipose tissue (BAT). We found that UCP1 was also expressed in heart...     

Oriented cell division: new roles in guiding skin wound repair and regeneration

Tissue morphogenesis depends on precise regulation and timely co-ordination of cell division and also on the control of the direction of cell division. Establishment of polarity division axis, correct alignment of the mitotic spindle, segregation of fate determinants equally or unequally between daughter cells, are essential for the realization of oriented cell division. Furthermore, oriented cell division is regulated by intrinsic cues, extrinsic cues and other cues, such as cell geometry and polarity. However, dysregulation of cell division orientation could lead to abnormal tissue development and function. In the present study, we review recent studies on the molecular mechanism of cell division orientation and explain their new roles in skin repair and regeneration.