Complete structure of eclosion hormone of Manduca sexta

The locations of the three disulfide bonds of eclosion hormone (EH) isolated from Manduca sexta were assigned by sequence analysis of thermolysin fragments and by comparison of a key heterodimeric fragment to regiospecifically synthesized parallel and antiparallel isomers. We elucidated the complete structure of Manduca EH as a 62-residue peptide which has three disulfide bonds between Cys¹⁴-Cys³⁸, Cys¹⁸-Cys³⁴, and Cys²¹-Cys⁴⁹.     

家蚕的抗氟性及其与数量性状的相关研究

测定家蚕幼虫抗氟中毒的抵抗能力,4龄>3龄>2龄。强抗原种杂变组成的杂种一代,抗性介于两亲之间,弱抗原种杂交组成的杂种一代,其抗性表现出超亲的遗传现象,不同浓度的氟素对品种间的生长发育影响有着显著的差异,说明了品种间的抗氟能力存在着差别;抗氟性与DNV抗性有着显著的相关性;与茧质性状表现为不显著的正相关,抗氟性与蚕血中Ca~(2+)、Mg~(2+)含量无明显的相关关系。     

Hydrophobic Bombyx mori Silk Fibroin: Routes to Functionalization with Alkyl Chains

Bombyx mori silk fibroin (SF) is a very versatile biopolymer due to its biocompatibility and exceptional mechanical properties which make possible its use as a functional material in several applications. SF can be modified with a large variety of chemical approaches which endow the material with tailored chemical–physical properties. Here, a systematic investigation of different routes is reported to graft long alkyl chains on SF based on both liquid- and solid-phase, aiming to modulate its hydrophobic behavior. The liquid phase method involves direct activation of SF tyrosine residues via diazo coupling and cycloaddition reactions, generating hydrophobic materials insoluble in any common solvent. The solid phase approach consists of the chemical modification of drop-casted SF films by esterification of hydroxyl groups of serine, threonine, and tyrosine SF residues with acyl chlorides of fatty acids. For the solid-state functionalization, a new class of hydrophobic pendant groups is synthesized, based on triple esters of gallic acid anhydrides, that are reacted with the biopolymer to further enhance its resulting hydrophobic features.     

钩藤及其有效成分的药理研究进展

回顾分析近年来国内外对钩藤及其所含主要化学成分的药理研究进展，提示钩藤对心血管系统、中枢神经系统以及血液系统等多方面均有作用。     

高效液相色谱法测定桂枝中3种有效成分的含量

目的:建立HPLC法测定桂枝中桂皮醛、栓皮酸和邻甲氧基栓皮醛的含量。方法:采用ODS色谱柱(150mm×4.6mm,5μm),以甲醇-水-冰乙酸(45:55:0.05)为流动相,流速为0.8 mL·min~(-1),紫外检测波长为280 nm。结果:栓皮醛、桂皮酸和邻甲氧基桂皮醛的线性范围(n=5)分别为0.125～2μg(r=0.999 8),0.003 2～2 μg(r=0.999 9),0.012 5～0.2μg(r=0.999 7),平均回收率(n=9)分别为99.3％,102.8％,98.9％。提取方法为甲醇冷浸12h。结论:本方法简便、准确,可为评价不同产地的桂枝质量提供依据。     

A serine protease homologue Bombyx mori scarface induces a short and fat body shape in silkworm

Body shape is one of the most prominent and basic characteristics of any organism. In insects, abundant variations in body shape can be observed both within and amongst species. However, the molecular mechanism underlying body shape fine‐tuning is very complex and has been largely unknown until now. In the silkworm Bombyx mori, the tubby (tub) mutant has an abnormal short fat body shape and the abdomen of tub larvae expands to form a fusiform body shape. Morphological investigation revealed that the body length was shorter and the body width was wider than that of the Dazao strain. Thus, this mutant is a good model for studying the molecular mechanisms of body shape fine‐tuning. Using positional cloning, we identified a gene encoding the serine protease homologue, B. mori scarface (Bmscarface), which is associated with the tub phenotype. Sequence analysis revealed a specific 312‐bp deletion from an exon of Bmscarface in the tub strain. In addition, recombination was not observed between the tub and Bmscarface loci. Moreover, RNA interference of Bmscarface resulted in the tub‐like phenotype. These results indicate that Bmscarface is responsible for the tub mutant phenotype. This is the first study to report that mutation of a serine protease homologue can induce an abnormal body shape in insects.     

Molecular cloning and characterization of peroxiredoxin 4 involved in protection against oxidative stress in the silkworm Bombyx mori

Peroxiredoxins (Prxs) are a ubiquitous family of proteins that play important roles in insects in protection against oxidative stress through the detoxification of cellular peroxides. Here, we describe the cloning and characterization of a Prx4 cDNA of the silkworm Bombyx mori (BmPrx4). The BmPrx4 gene has an open reading frame of 744 bp encoding 248 amino acids and a conserved motif, VCP, involved in its presumed redox functions. The heterologously expressed proteins of the gene in Escherichia coli showed antioxidant activity, removed hydrogen peroxide and protected DnA. Western blotting analysis showed the presence of BmPrx4 in the haemolymph, suggesting that the protein is secretable. Moreover, BmPrx4 was expressed at all developmental stages. The expression level of BmPrx4 was relatively low during the feeding stage but high at the wandering stage. BmPrx4 was induced by quercetin or temperature stress. Immunohistochemical analysis revealed that BmPrx4 is present in the brain, neurones and olfactory organ of the head in silkworms. Overall, our results indicate that the expression profile of BmPrx4 correlates well with protection from oxidative damage. Our data provide clues for the development of control technology for agricultural and forestry pests as the silkworm is a representative of lepidopteran pests.     

基于网络药理学和分子对接探讨钩藤-全蝎药对治疗支气管哮喘的作用机制＊

目的通过网络药理学和分子对接探究钩藤-全蝎药对治疗支气管哮喘的药理作用机制。方法通过TCMSP、TCMIP数据库搜集钩藤、全蝎的活性成分及其作用靶点,并使用Cytoscape软件进行可视化分析成分-靶点网。通过OMIM、GeneCards数据库搜集支气管哮喘的疾病靶点,整合钩藤-全蝎药对与支气管哮喘的共有靶点。利用String平台构建对共有靶点互作PPI网络,并进行GO和KEGG富集分析,通过Cytoscape软件构建成分-靶点-通路网络模型。最后通过Autodock分子对接进行验证。结果经过筛选发现钩藤-全蝎药对37个活性化合物和234个药物靶点,与哮喘6010个靶点取交集得到35个共有靶点。钩藤-全蝎包含槲皮素、山奈酚、育亨宾碱、β-谷甾醇等重要活性成分;根据PPI网络分析,核心网络连接度高的潜在治疗靶点有IL6、CASP3、ECFR、ESR1、MAPK8等;根据KEGG富集分析结果显示,钩藤-全蝎药对主要通过PI3 K-Akt信号通路、TNF信号通路,HIF-1信号通路、M APK信号通路、NF-κB信号通路等来治疗哮喘;钩藤-全蝎药对活性成分与核心靶点的分子对接结果均显示出较好的结合活性。结论钩藤-全蝎药对治疗哮喘呈现出多成分、多靶点、多通路的特点,其核心成分槲皮素、山奈酚、育亨宾碱、β-谷甾醇等可能通过CASP3、MAPK8、ESR1、IL6、ECFR等靶点调节多条通路发挥抗炎、调节免疫、抗氧化应激、改善气道重塑等作用,从而对哮喘达到有效的治疗。     

Maternal GABAergic and GnRH/corazonin pathway modulates egg diapause phenotype of the silkworm Bombyx mori

Diapause represents a major developmental switch in insects and is a seasonal adaptation that evolved as a specific subtype of dormancy in most insect species to ensure survival under unfavorable environmental conditions and synchronize populations. However, the hierarchical relationship of the molecular mechanisms involved in the perception of environmental signals to integration in morphological, physiological, behavioral, and reproductive responses remains unclear. In the bivoltine strain of the silkworm Bombyx mori, embryonic diapause is induced transgenerationally as a maternal effect. Progeny diapause is determined by the environmental temperature during embryonic development of the mother. Here, we show that the hierarchical pathway consists of a γ-aminobutyric acid (GABA)ergic and corazonin signaling system modulating progeny diapause induction via diapause hormone release, which may be finely tuned by the temperature-dependent expression of plasma membrane GABA transporter. Furthermore, this signaling pathway possesses similar features to the gonadotropin-releasing hormone (GnRH) signaling system for seasonal reproductive plasticity in vertebrates.

To ensure survival under unfavorable environmental conditions and synchronize populations, most insect species enter diapause, which is a seasonal adaptation that evolved as a specific subtype of dormancy (1, 2). Diapause is not a passive response to changing conditions but rather an actively induced state that precedes adverse natural situations. Therefore, this diapause phenotype is accompanied by changes in energy metabolism or storage to improve cold/stress tolerance in later life stages, or progeny via reproductive switch (3). Although it has been generally suggested that brain/neuroendocrine systems are associated with this seasonal reproductive plasticity in both vertebrates and invertebrates (3, 4), the hierarchical relationship of the molecular mechanisms involved in the perception of environmental signals to integration into morphological, physiological, behavioral, and reproductive responses, known as the diapause syndrome, remains unclear (3).The silkworm Bombyx mori is a typical insect that arrests normal development during early embryogenesis, which is accompanied by metabolic changes in diapause (5, 6). The development of diapause-destined embryos is arrested during the G2 cell cycle stage immediately after the formation of the cephalic lobe and telson and sequential segmentation of the mesoderm (7). The bivoltine strain of B. mori has two generations per year, and progeny diapause is transgenerationally induced as a maternal effect and is determined by the environmental temperature, photoperiod, and nutrient conditions during embryonic and larval development of the mother (5, 6). The temperature signal during the mother’s embryonic development predominantly affects diapause determination, even if silkworms of the bivoltine Kosetsu strain are exposed to all cases of photoperiods during embryonic and larval development. In the Kosetsu strain, when eggs are incubated at 25 °C under continuous darkness, the resultant female moths (25DD) lay diapause eggs in almost all cases. In contrast, incubation of eggs at 15 °C in dark condition results in moths (15DD) that lay nondiapause eggs in almost all cases (6).Embryonic diapause is induced by the diapause hormone (DH) signaling pathway, which consists of highly sensitive and specific interactions between a neuropeptide, DH, and DH receptor (DHR) (6, 8). DH is exclusively synthesized in seven pairs of neurosecretory cells (DH-PBAN–producing neurosecretory cells [DHPCs]) located within the subesophageal ganglion (SG) in the mother’s generation (6). DH is released into the hemolymph during pupal–adult development and acts on the DHR, which belongs to the G protein-coupled receptors (GPCRs) (9). DH levels in the hemolymph are higher in the 25DD than 15DD pupae in the middle of pupal–adult development when the developing ovaries are sensitive to DH (6). Furthermore, the embryonic Bombyx TRPA1 ortholog (BmTRPA1) acts as a thermosensitive channel that is activated at temperatures above ∼21 °C and affects diapause induction through DH release (10). However, there remain questions about the thermal information that is received by BmTRPA1 and linked to DH signaling to induce diapause.From the 1950s, it has been suggested that the DH release was controlled by signals derived from certain region(s) in the brain based on surgical experiments, such as midsagittal bisection or transection (11–13). Especially, the operation in nondiapause producers changed them to diapause producers while transection of the protocerebrum had no effect on the diapause producers. These surgical results suggested the involvement of the protocerebrum in the inhibitory control of DH secretion (12, 14). Furthermore, the accumulation of the ovarian 3-hydroxykynurenine (3-OHK) pigment that accompanies the diapause syndrome was affected by injection with γ-aminobutyric acid (GABA) and the plant alkaloid picrotoxin (PTX), which is a widely used ionotropic GABA and glycine receptor antagonist (15, 16), and the selective ionotropic GABA receptor (GABAR) antagonist bicuculline. This suggests that a GABAergic neurotransmission via ionotropic GABAR is involved in DH secretion, which may be active in nondiapause producers but inactive in diapause producers throughout the pupal–adult development (14, 17). In general, ionotropic GABAR is composed of homo- or hetero-pentameric subunits. All known GABAR subunits display a similar structural scheme, with a large N-terminal extracellular domain involved in the formation of a ligand-binding pocket and a pore domain made of four transmembrane alpha-helices (TM1–TM4) (16, 18). Four homologous sequences of the ionotropic GABAR subunit genes were identified as RDL, LCCH3, GRD, and a GRD-like sequence named 8916 in various insects (19). However, the in vivo physiological roles of both signals derived from the brain and the GABAergic pathway in diapause induction have not been previously investigated.Corazonin (Crz) is an undecapeptide neurohormone sharing a highly conserved amino acid (a.a.) sequence across insect lineages and is involved in different physiological functions, such as heart contraction (20), stress response (21, 22), various metabolic activities (23–25), female fecundity (26), melanization of locust cuticles (27), regulation of ecdysis (28, 29), and control of caste identity (30). Moreover, Crz belongs to the gonadotropin-releasing hormone (GnRH) superfamily alongside adipokinetic hormone (AKH) and AKH/Crz-related peptide (ACP). Duplicates of an ancestral GnRH/Crz signaling system occurred in a common ancestor of protostomes and deuterostomes through coevolution of the ligand receptor (31, 32).Herein, we demonstrated that the hierarchical pathway consists of a GABAergic and Crz signaling system modulating progeny diapause induction by acting on DH release. We propose that the PTX-sensitive GABAergic signal may act to chronically suppress Crz release in dorsolateral Crz neurons (under nondiapause conditions) and that diapause conditions (or PTX injection) inhibits GABAergic signaling, resulting in accelerated Crz release, which in turn induces DH release. GABA signaling may be finely tuned by the temperature-dependent expression of the plasma membrane GABA transporter (GAT), which differs between the 25DD and 15DD conditions. Furthermore, this signaling pathway possesses similar features to the GnRH signaling system with respect to seasonal reproductive plasticity in vertebrates.