Genome-wide identification,classification, and expression profiling of serine esterases and other esterase-related proteins in the tobacco hornworm,Manduca sexta

Serine esterases (SEs) are hydrolases that catalyze the conversion of carboxylic esters into acids and alcohols. Lipases and carboxylesterases constitute two major groups of SEs. Although over a hundred of insect genomes are known, systematic identification and classification of SEs are rarely performed, likely due to large size and complex composition of the gene family in each species. Considering their key roles in lipid metabolism and other physiological processes, we have categorized 144 M. sexta SEs and SE homologs (SEHs), 114 of which contain a motif of GXSXG. Multiple sequence alignment and phylogenetic tree analysis have revealed 39 neutral lipases (NLs), 3 neutral lipase homologs (NLHs), 11 acidic lipases (ALs), 3 acidic lipase homologs (ALHs), a lipase-3, a triglyceride lipase, a monoglyceride lipase, a hormone-sensitive lipase, and a GDSL lipase. Eighty-three carboxylesterase genes encode 29 α-esterases (AEs), 12 AEHs (e.g., SEH4-1–3), 20 feruloyl esterases (FEs), 2 FEHs, 2 β-esterases (BEs), 2 integument esterases (IEs), 1 IEH, 4 juvenile hormone esterases, 2 acetylcholinesterases, gliotactin, 6 neuroligins, neurotactin, and an uncharacteristic esterase homolog. In addition to these GXSXG proteins, we have identified 26 phospholipases and 13 thioesterases. Expression profiling of these genes in specific tissues and stages has provided insights into their functions including digestion, detoxification, hormone processing, neurotransmission, reproduction, and developmental regulation. In summary, we have established a framework of information on SEs and related proteins in M. sexta to stimulate their research in the model species and comparative investigations in agricultural pests or disease vectors.     

山西糜子核心种质分子身份证构建

为快速鉴定糜子(Panicum miliaceum)资源, 建立分子标记检测平台, 以272份山西糜子核心种质为研究材料, 利用85对简单重复序列(SSR)引物, 应用ID Analysis 4.0软件, 构建DNA分子身份证。结果表明, 对85对SSR引物进行筛选, 发现20对引物组合(RYW67、RYW53、RYW37、RYW65、RYW62、RYW77、RYW5、RYW49、RYW84、RYW19、RYW11、RYW40、RYW54、RYW28、RYW31、RYW7、RYW16、RYW8、RYW9和RYW18)可区分272份材料。共检测到等位变异(Na) 60个, 平均每个位点检出3个; Shannon多样性指数(I)为0.957 8 (RYW16)-1.096 7 (RYW5), 平均值为1.055 2; 多态性信息含量(PIC)为0.604 4 (RYW77)-0.753 0 (RYW37), 平均值为0.692 1。利用20对引物构建山西糜子核心种质的字符串、条形码和二维码DNA分子身份证, 可为种质身份标识和溯源提供实践路径。     

1,5-diamino-2-pentyne is both a substrate and inactivator of plant copper amine oxidases.

1,5-diamino-2-pentyne (DAPY) was found to be a weak substrate of grass pea (Lathyrus sativus, GPAO) and sainfoin (Onobrychis viciifolia, OVAO) amine oxidases. Prolonged incubations, however, resulted in irreversible inhibition of both enzymes. For GPAO and OVAO, rates of inactivation of 0.1-0.3 min(-1) were determined, the apparent KI values (half-maximal inactivation) were of the order of 10(-5) m. DAPY was found to be a mechanism-based inhibitor of the enzymes because the substrate cadaverine significantly prevented irreversible inhibition. The N1-methyl and N5-methyl analogs of DAPY were tested with GPAO and were weaker inactivators (especially the N5-methyl) than DAPY. Prolonged incubations of GPAO or OVAO with DAPY resulted in the appearance of a yellow-brown chromophore (lambda(max) = 310-325 nm depending on the working buffer). Excitation at 310 nm was associated with emitted fluorescence with a maximum at 445 nm, suggestive of extended conjugation. After dialysis, the color intensity was substantially decreased, indicating the formation of a low molecular mass secondary product of turnover. The compound provided positive reactions with ninhydrin, 2-aminobenzaldehyde and Kovacs' reagents, suggesting the presence of an amino group and a nitrogen-containing heterocyclic structure. The secondary product was separated chromatographically and was found not to irreversibly inhibit GPAO. MS indicated an exact molecular mass (177.14 Da) and molecular formula (C10H15N3). Electrospray ionization- and MALDI-MS/MS analyses yielded fragment mass patterns consistent with the structure of a dihydropyridine derivative of DAPY. Finally, N-(2,3-dihydropyridinyl)-1,5-diamino-2-pentyne was identified by means of 1H- and 13C-NMR experiments. This structure suggests a lysine modification chemistry that could be responsible for the observed inactivation.     

Kinetic studies of electron transfer in the cyt b 5 : metHb system

 The kinetics of methemoglobin reduction by cytochrome b ₅ has been studied by stopped-flow and saturation transfer NMR. A forward rate constant k _f = 2.44×10⁴ M^–1 s^–1 and a reverse rate constant k _b = 540 M^–1s^–1 have been observed at 10 mm, pH 6.20, 25  °C. The ratio k _f/k _b = k _eq = 43.6 is in good agreement with the equilibrium constant calculated from the electrochemical potential between cyt b ₅ and methemoglobin. A bimolecular collisional mechanism is proposed for the electron transfer from cyt b ₅ to methemoglobin based on the kinetic data analysis. The dependence of the rate constants on ionic strengths supports such collisional mechanism. It is also found that the reaction rate strongly depends on the conformations of methemoglobin. Received: 20 February 1996 / Accepted: 4 June 1996     

高压静电场分离水稻、油菜及芝麻种子对萌发期生物效应的影响

落入高压静电场内的水稻、芝麻及油菜种子,在场的作用下,即产生沿电场方向的位移,在同一跌落高度下,重量基本相同的种子,其分离距离产生很大的差异,且分离距离与种子的发芽率及发芽势的改善程度存在着较为明显的相关关系,研究中证实,种子活力强度得到提高,其α淀粉酶活性、蛋白酶活性、脂肪酶活性及电导率得到明显的改善。     

耐热蛋白质延长因子(EF-Tu)的分子和功能的性质(英文)

本文用亲和层析法从Calderobacteriumhydrogenophilum(极端耐热细菌)中分离得到纯的耐热蛋白质延长因子。测得其相对的分子量为51000。该蛋白质对热极其稳定,从膜过滤分析法测定EF-Tu 的活性可知,在80℃加热5 min后,原活性仅仅失去50%。Ouchterlony双向免疫扩散的结果表明,该蛋白延长因子与E.coli 延长因子有着抗原的相似性。而且该因子只含一个半胱氨酸残基,其位置在半胱氨酸81,即肽段T_(13)。Southern 杂交试验的结果显示出C.hydrogenophilum 的染色体DNA 中可能有两个基因编码同一蛋白。     

Circ_0008542 in osteoblast exosomes promotes osteoclast-induced bone resorption through m6A methylation

With an increasing aging society, China is the world’s fastest growing markets for oral implants. Compared with traditional oral implants, immediate implants cause marginal bone resorption and increase the failure rate of osseointegration, but the mechanism is still unknown. Therefore, it is important to further study mechanisms of tension stimulus on osteoblasts and osteoclasts at the early stage of osseointegration to promote rapid osseointegration around oral implants. The results showed that exosomes containing circ_0008542 from MC3T3-E1 cells with prolonged tensile stimulation promoted osteoclast differentiation and bone resorption. Circ_0008542 upregulated Tnfrsf11a (RANK) gene expression by acting as a miR-185-5p sponge. Meanwhile, the circ_0008542 1916-1992 bp segment exhibited increased m6A methylation levels. Inhibiting the RNA methyltransferase METTL3 or overexpressing the RNA demethylase ALKBH5 reversed osteoclast differentiation and bone resorption induced by circ_0008542. Injection of circ_0008542 + ALKBH5 into the tail vein of mice reversed the same effects in vivo. Site-directed mutagenesis study demonstrated that 1956 bp on circ_0008542 is the m6A functional site with the abovementioned biological functions. In conclusion, the RNA methylase METTL3 acts on the m6A functional site of 1956 bp in circ_0008542, promoting competitive binding of miRNA-185-5p by circ_0008542, and leading to an increase in the target gene RANK and the initiation of osteoclast bone absorption. In contrast, the RNA demethylase ALKBH5 inhibits the binding of circ_0008542 with miRNA-185-5p to correct the bone resorption process. The potential value of this study provides methods to enhance the resistance of immediate implants through use of exosomes releasing ALKBH5.Subject terms: Epigenetics, Predictive markers