Chemoenzymatic synthesis and lectin recognition of a selectively fluorinated glycoprotein

A chemoenzymatic glycosylation remodeling method for the synthesis of selectively fluorinated glycoproteins is described. The method consists of chemical synthesis of a fluoroglycan oxazoline and its use as donor substrate for endoglycosidase (ENGase)-catalyzed transglycosylation to a GlcNAc-protein to form a homogeneous fluoroglycoprotein. The approach was exemplified by the synthesis of fluorinated glycoforms of ribonuclease B (RNase B). An interesting finding was that fluorination at the C-6 of the 6-branched mannose moiety in the Man3GlcNAc core resulted in significantly enhanced reactivity of the substrate in enzymatic transglycosylation. A structural analysis suggests that the enhancement in reactivity may come from favorable hydrophobic interactions between the fluorine and a tyrosine residue in the catalytic site of the enzyme (Endo-A). SPR analysis of the binding of the fluorinated glycoproteins with lectin concanavalin A (con A) revealed the importance of the 6-hydroxyl group on the α-1,6-branched mannose moiety in con A recognition. The present study establishes a facile method for preparation of selectively fluorinated glycoproteins that can serve as valuable probes for elucidating specific carbohydrate–protein interactions.     

Synthesis and pharmacological evaluation of novel bisindolylalkanes analogues

In an effort to develop potent anti-cancer chemopreventive agents that act on topoisomerase II, a novel series of bisindolylalkanes analogues such as 3,3′-(thiochroman-4,4-diyl)bis(1H-indole) are synthesized. Structures of all compounds are elucidated by ¹H NMR, ¹³C NMR and HRMS. Anti-proliferative activities for all of these compounds are investigated by the method of MTT assay on 7 human cancer lines. Most of them showed antitumor activities in vitro, the half maximal inhibitory concentration (IC₅₀) value is 7.798 μg/mL of 3a against MCF7. Compound 3a showed comparable topoisomerase II inhibitory activity to etoposide (VP-16) at 100 μM concentration. The rest of the compounds also showed varying degree topoisomerase II inhibitory activity.     

年龄增长对GRK5基因缺陷小鼠海马内肿胀轴突丛形成与积累的影响

目的研究G蛋白偶联受体（G protein-coupled receptors）激酶5（GPCR kinase-5,GRK5）基因缺陷和老化交互作用对阿尔茨海默病（Alzheimer＇s disease,AD）早期的病理改变-海马内肿胀轴突丛（swollen axonal clusters,SACs）出现和积累的影响。方法选取5、6、7、9、12～13、18—19月龄雌性GRK5基因敲除小鼠（GRK5 Knockout,GRK5KO）作为观察对象,另选取年龄匹配的雌性野生型（wild type,WT）小鼠为对照,每个年龄段GRK5KO和WT小鼠各4只。用抗人神经原纤维缠结（neurofibrillary tangles,NFTs）特异性抗体的免疫荧光染色方法观察海马内SACs的变化。结果所有小鼠随着年龄增长,海马内SACs逐渐增加;GRKSKO小鼠组海马内NFT^＋ SACs数量较WT型小鼠组显著增加（P〈0．01）;双因素方差分析显示遗传性GRK5基因缺陷和老化双因素对海马内NFT^＋SACs的影响有显著协同效应（P〈0．01）。结论在促进早期AD病理发生的过程中,GRK5缺陷和老化双因素共同加剧了雌性GRKSKO小鼠海马内SACs的形成与积累。     

Ezrin蛋白在眼睑基底细胞癌组织中的表达及其意义

目的探讨Ezrin蛋白在眼睑基底细胞癌组织中的表达。方法收集武汉市中心医院和武汉大学人民医院病理科2002—2009年手术切除及活检的眼睑基底细胞癌（basalcellcarcinoma,BCC）标本共20例,另取癌周围组织5例作对照。采用免疫组织化学方法观察各组细胞内Ezrin蛋白表达。利用图像分析系统测定Ezrin蛋白在以上各组中表达的平均光密度和平均阳性面积率。结果眼睑基底细胞癌组织中Ezrin蛋白呈高表达;癌旁组织中Ezrin蛋白呈低表达。图像分析结果显示：眼睑基底细胞癌组织与癌旁组织之间Ezrin蛋白的平均光密度及阳性面积率的差异有显著性意义（P〈0．05）。结论Ezrin蛋白在眼睑基底细胞癌的发生、发展过程中起了重要作用。     

Algicidal activity against Skeletonema costatum by marine bacteria isolated from a high frequency harmful algal blooms area in southern Chinese coast

Four marine bacterial strains P1, P5, N5 and N21 were isolated from the surface water and sediment of Mirs Bay in southern Chinese coast using the liquid infection method with 48-well plates. These bacteria were all shown to have algicidal activities against Skeletonema costatum. Based on morphological observations, biochemical tests and homology comparisons by 16S rDNA sequences, the isolated strains P1, P5, N5 and N21 were identified as Halobacillus sp., Muricauda sp., Kangiella sp. and Roseivirga sp., respectively. Our results showed that bacterial strain P1 killed S. costatum by release of heat labile algicide, while strains P5, N5 and N21 killed them directly. The algicidal processes of four bacterial strains were different. Strains P1, N5 and N21 disrupted the chain structure and S. costatum appeared as single cells, in which the cellular components were aggregated and the individual cells were inflated and finally lysed, while strain P5 decomposed the algal chains directly. We also showed that the algicidal activities of the bacterial strains were concentration-dependent. More specifically, 10?% (v/v) of bacteria in algae showed the strongest algicidal activities, as all S. costatum cells were killed by strains N5 and N21 within 72?h and by strains P1 and P5 within 96?h. 5?% of bacteria in algae also showed significant algicidal activities, as all S. costatum were killed by strains N5, P5 and N21 within 72, 96 and 120?h, respectively, whereas at this concentration, only 73.4?% of S. costatum cells exposed to strain P1 were killed within 120?h. At the concentration of 1?% bacteria in algae, the number of S. costatum cells continued to increase and the growth rate of algae upon exposure to strain N5 was significantly inhibited.     

Proteomic and physiological analyses reveal detoxification and antioxidation induced by Cd stress in Kandelia candel roots

The heavy metal Cadmium (Cd), added to the water bodies through weathering of rocks and human activities, constitutes one of the major environmental pollutants toxic to plants. This study examines the proteome changes in roots of actively growing Kandelia candel (L.) Druce when challenged with Cd. This mangrove-like species proliferates in estuaries and bays and is a potential choice for phytoremediation of Cd. A total of 53 proteins were up- or down-regulated following a short-term Cd treatment. The identities of the differentially expressed proteins were determined by MALDI-TOF/TOF. Approximately half of the up-regulated proteins are involved in oxidative response, including antioxidant enzymes, enzymes required for glutathione biosynthesis, enzymes in TCA and PPP cycles for generating ATP, NADH and NADPH. These results support the prediction that a prompt antioxidative response is necessary for the reduction of the oxidative stress caused by Cd and set the stage for further investigating of Cd up-regulated proteins in Kandelia candel.     

Morphology,ontogeny, and molecular phylogeny of two novel bakuellid-like hypotrichs (Ciliophora: Hypotrichia), with establishment of two new genera

The morphology, ontogeny and molecular phylogeny of Apobakuella fusca gen. n., sp. n. and Parabistichella variabilis gen. n., sp. n., from south China were investigated. Apobakuella fusca, brown colored, demonstrates bakuellid-like infraciliature, and a similar ontogenesis as the genus Bakuella. It is argued, however, that this species represents a novel genus, Apobakuella, which is characterized by two or more marginal rows on the right, several buccal and parabuccal cirri, and lack of frontoterminal and caudal cirri. Phylogenetic analysis based on SSU rRNA gene sequences supports the close relationship of Apobakuella with Neobakuella and Diaxonella within the core Urostylida. By contrast, Parabistichella variabilis has a dominant frontoventral row, few midventral pairs, a long midventral row, and one marginal row on each side. Its morphogenesis exhibits: (1) partial reorganization of the parental adoral membranelles; (2) over six frontoventral-transverse cirri anlagen; (3) intrakinetal development of the midventral row; and (4) very likely, formation of the frontoventral row from the midventral row anlage. Both the morphological characteristics and the SSU rRNA gene sequences suggest that it is incertae sedis among the basal hypotrichs. Further investigation of key taxa with additional molecular markers is required to reveal a better understanding on the phylogeny of Parabistichella.