Site-directed mutagenesis of UbiA to promote menaquinone biosynthesis in Elizabethkingia meningoseptica

To increase the menaquinone (MK) content of an Elizabethkingia meningoseptica, site-directed mutagenesis was generated to suppress 4-hydroxybenzoate octaprenyl transferase (UbiA) activity and subsequently blocked the ubiquinone (UQ) biosynthesis pathway. Fourteen conserved residues except L174 and G211 were mutated to analyze the effect of site-directed mutagenesis. The expression of UbiA in twelve mutants was decreased in both mRNA and protein levels, which resulted in the decrease of UQ concentration. Based on MenA expression level, 12 mutants were divided into two groups. Second group such as N72A, D76A, K81A, L139A, and D198A enhanced the expression of MenA, which increased MK production by 127.1%, 87.9%, 96.2%, 109.7% and 130.0% in wt-EmUbiA, respectively. In general, blocking UQ synthesis pathway for by site-directed mutagenesis of the active site of UbiA in E. meningoseptica was a promising strategy to increase MK production in E. meningoseptica.     

枯草芽胞杆菌异戊二烯酶ComQ的生物信息学分析及对生物膜形态的影响

[目的]枯草芽胞杆菌ComQ是一种类异戊二烯生物合成酶.利用生物信息学预测分析了ComQ的生物学特性,对comQ基因进行过表达和敲除,构建突变菌,孔板发酵培养验证生物膜形态变化.[方法]运用NCBI (National Center for Biotechnology Information)网站里的Protein数据...     

Distribution of endocrine cells in the digestive tract of Alligator sinensis during the active and hibernating period

The digestive tract is the largest endocrine organ in the body; the distribution pattern of endocrine cells varies with different pathological and physiological states. The aim of the present study was to investigate the distributed density of 5-hydroxytryptamine (5-HT), gastrin (GAS), somatostatin (SS) and vasoactive intestinal peptide (VIP) immunoreactive (IR) cells in the digestive tract of Alligator sinensis during the active and hibernating period by immunohistochemical (IHC) method. The results indicated that 5-HT-IR cells were distributed throughout the entire digestive tract, which were most predominant in duodenum and jejunum. The density increased significantly in stomach and duodenum during hibernation. GAS-IR cells were limited in small stomach and small intestine. The density decreased significantly in small stomach during hibernation, while increased in duodenum. What's more, most of the endocrine cells in duodenum were generally spindle shaped with long cytoplasmic processes ending in the lumen during hibernation. SS-IR cells were limited in stomach and small stomach. The density increased in stomach while decreased in small stomach during hibernation, meanwhile, fewer IR cells occurred in small intestine. VIP-IR cells occurred in stomach and small stomach. The density decreased in small stomach, while increased in stomach during hibernation. These results indicated that the endocrine cells in different parts of digestive tract varied differently during hibernation, their changes were adaptive response to the hibernation.     

基于系统发生探讨绿带翠凤蝶和西番翠凤蝶的分类地位(英文)

绿带翠凤蝶和西番翠凤蝶的分类问题存在一定的争议。应用分子系统学方法对这一问题进行了研究。对6个不同地区的24个绿带翠凤蝶、2个地区的16个西番翠凤蝶个体的COI(579bp)和COII(655bp)基因测序,绿带翠凤蝶与西番翠凤蝶的遗传距离为0至0.6%,共获得了15个单倍型。结果显示这些单倍型不能形成各自独立的单系群,因此认为绿带翠凤蝶和西番翠凤蝶为近期分化的两个种。     

Simulation for diffusion behaviour of molecules in nanopattern-supported lipid bilayers based on random walk theory

In both the scientific and the technological approach, molecular manipulation with microscopic obstacles is of great importance. Recently, the application of a self-spreading lipid bilayer has attracted growing interest for its ability to transport any molecule in any desired direction. In this paper, we propose a new model, which imitates a self-spreading lipid bilayer on a substrate with metallic nanobarriers, to simulate the diffusion behaviours of molecules within it based on the random walk (RW) theory. The barriers are designed as Jones Tsai's experiments. The barrier's length, width, spacing, gap and interaction energy with molecules are investigated in this paper. The mean square displacement and diffusion coefficients (D) were calculated based on our simulation results. The results show that our simulation is consistent with the experiments. Comparing with the experimental techniques, this simulation work has improved the time- and space-resolution. Furthermore, it can simulate in rather long time-scale. Our RW models are expected to provide theoretical foundation for single molecular observation of hop diffusion in a lipid bilayer with metallic nanogates.     

A new species of Lysimachia (Myrsinaceae) from Dabieshan Mountain,China

A new species of Myrsinaceae, Lysimachia jinzhaiensis S.B. Zhou & K. Liu, is described and illustrated from Dabieshan mountain, Anhui, China. It is similar to L. christiniae in the prostrate stem, opposite leaves, yellow flowers born singly in leaf axils, but differs by being glabrous throughout or glandular on young parts, and having quadrangular stem, corolla with densely transparent glandular, orange-red corolla base with lobes being significantly overlapping and contorting to left in bud. Moreover, L. jinzhaiensis have a different karyotype, formulated as 2n = 2m + 2sm + 10st (2SAT) + 10t.     

拱殖嗜渣螨各发育阶段的体表形态观察

【目的】观察和认识拱殖嗜渣螨Chortoglyphus arcuatus不同发育阶段主要外部形态特征及超微结构。【方法】用啤酒酵母粉纯化饲养拱殖嗜渣螨,选取不同发育阶段个体清洁后,分别利用体视显微镜、光学显微镜以及扫描电子显微镜对螨体颜色、形态特征、局部特征以及超微结构进行观察。【结果】成螨颜色为鲜明的淡棕红色,其他发育阶段均为乳白色。躯体硬,卵圆形。无背横沟划分前足体和后半体。螯肢发达,螯钳剪状,有纵纹,具明显的齿。外顶毛有栉齿。颚体基部腹面有细横纹。体躯刚毛短,光滑。雌螨生殖孔位于Ⅲ和Ⅳ基节之间,覆有骨化的生殖板。生殖板后缘光滑、弓形。雄螨阳茎位于Ⅰ和Ⅱ基节之间,长且弯曲、管状。有肛吸盘,漏斗状。有跗节吸盘。【结论】本研究补充了拱殖嗜渣螨文献未记载的一些特征,如卵、幼螨和若螨体色,螯肢背面和颚体腹面刻纹等,有助于该螨及其近缘种的快速鉴定和分类研究。     

3-Oxo-14α,15α-epoxyschizozygine: A new schizozygane indoline alkaloid from Schizozygia coffaeoides

The stem bark extract of Schizozygia coffaeoides (Apocynaceae) showed moderate antiplasmodial activity (IC₅₀ = 8–12 μg/mL) against the chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of Plasmodium falciparum. Chromatographic separation of the extract led to the isolation of a new schizozygane indoline alkaloid, named 3-oxo-14α,15α-epoxyschizozygine. In addition, two dimeric anthraquinones, cassiamin A and cassiamin B, were identified for the first time in the family Apocynaceae. The structures of the isolated compounds were deduced on the basis of spectroscopic evidence. The schizozygane indole alkaloids showed good to moderate antiplasmodial activities (IC₅₀ = 13–52 μМ).     

Artostyracins A–C,three new isoprenylated 2-arylbenzofurans from Artocarpus styracifolius

Three new isoprenylated 2-arylbenzofurans, namely artostyracins A–C (1–3, resp.), together with a known one (4), were isolated from the root of Artocarpus styracifolius Pierre. Their structures were determined by spectroscopic methods (1D and 2D NMR, UV, IR, and HR-ESI-MS). All of the compounds were evaluated for the anti-respiratory burst properties using a cellular model reproduced by chemical stimulation of rat neutrophils. Compounds 1 and 3 offered the potently inhibitory effects on respiratory burst of rat neutrophils with IC₅₀ values of 1.42 and 1.91 μM, while compounds 2 and 4 revealed moderate suppression activity with IC₅₀ values of 11.56 and 46.91 μM.