Development of a set of expression vectors in Hansenula polymorpha

Four expression vectors based on formate dehydrogenase promoter (FMDp) and methanol oxidase promoter (MOXp) from Hansenula polymorpha were developed to express heterologous genes in Hansenula polymorpha. A secretion signal sequence of the mating factor-alpha from Saccharomyces cerevisiae was inserted in the secretory expression plasmids for efficient secretion. A modified green fluorescent protein (mGFP5) was used as the marker of expression for the first time in H. polymorpha NCYC495 (leu 1.1) to determine the expression ability of these plasmids. The mGFP5 thus expressed retained its biochemical and physiological properties, such as accumulation inside cells and efficient secretion into the culture media. These results indicated that the four integrative vectors are useful expression systems which could be directly applied for production of heterologous proteins of interests in H. polymorpha.     

Propagation of potato tubers in a nutrient mist bioreactor

The newly designed nutrient mist bioreactor provided an environment supporting multiple-layer culture. In vitro tubers of potato (Solanum tuberosum L.) were induced and cultured in this bioreactor by using two culture methods. The percentage of the inocula eventually forming tubers in a two-step method was 98% with only 54% being formed in a one-step method. The two-step method improved the efficiency of tuber induction, expedited and synchronized the tuberization. © Rapid Science Ltd. 1998     

枳壳外植体离体再生及农杆菌介导的遗传转化

以枳壳实生苗的上胚轴及茎段为材料,在附加有ＢＡ和ＭＴ培养基上进行培养,上胚轴出芽率普遍高于茎段,ＢＡ为１ｍｇ／Ｌ时,出芽率最高,ＢＡ浓度升高,出芽率随之下降。外植体在培养基上的接种方式,对出芽有一定影响,上胚轴切段 形态学下端垂直插入,出芽率高。     

A Polymorphism Within the 3′UTR of <Emphasis Type="Italic">NLRP3</Emphasis> is Associated with Susceptibility for Ischemic Stroke in Chinese Population

Stroke was regarded as a severe disorder with high morbidity and high mortality worldwide, ischemic stroke (IS) accounts for 85 to 90 % of new increased stroke cases. Partial mechanisms were elucidated by genetic factors including genomic instability such as single nucleotide polymorphism (SNP). Previous reports demonstrated that inflammation was involved in IS, NLRP3 [nucleotide-binding domain (NOD)-like receptor protein 3], acting as a specific inflammatory gene, however, its function and influence on IS was not well clarified. In this study, a case–control study including 1102 IS patients and 1610 healthy controls was conducted to investigate the association between IS susceptibility with a SNP (rs10754558) in 3′UTR of NLRP3. Logistic regression analysis showed that the heterozygote and the homozygote GG confer a significantly increased risk of CRC after controlling for other covariates (adjusted OR = 1.52, 95 % C.I. 1.19–1.97, P = 0.002; adjusted OR = 2.22, 95 % C.I. 2.18–3.67, P < 0.001, respectively). Carriage of G allele was associated with a greatly increased risk of developing the disease (OR = 1.69, 95 % C.I. 1.31–1.83, P < 0.001). Stratification analysis found that hypertension had interaction with rs10754558 to modulate IS risk. Further in vitro assay revealed that rs10754558 can affect mRNA level of NLRP3, suggesting its possible functional significance. Our data suggested that genetic polymorphisms in NLRP3 may influence IS risk in Chinese population. Replication of our studies in other populations and further functional studies are required for complete comprehension of the roles of NLRP3 polymorphisms in IS risk.     

Mouse development and cell proliferation in the absence of D-cyclins

D-type cyclins (cyclins D1, D2, and D3) are regarded as essential links between cell environment and the core cell cycle machinery. We tested the requirement for D-cyclins in mouse development and in proliferation by generating mice lacking all D-cyclins. We found that these cyclin D1(-/-)D2(-/-)D3(-/-) mice develop until mid/late gestation and die due to heart abnormalities combined with a severe anemia. Our analyses revealed that the D-cyclins are critically required for the expansion of hematopoietic stem cells. In contrast, cyclin D-deficient fibroblasts proliferate nearly normally but show increased requirement for mitogenic stimulation in cell cycle re-entry. We found that the proliferation of cyclin D1(-/-)D2(-/-)D3(-/-) cells is resistant to the inhibition by p16(INK4a), but it critically depends on CDK2. Lastly, we found that cells lacking D-cyclins display reduced susceptibility to the oncogenic transformation. Our results reveal the presence of alternative mechanisms that allow cell cycle progression in a cyclin D-independent fashion.     

The structure-specific nicking of small heteroduplexes by the RAG complex: implications for lymphoid chromosomal translocations

During V(D)J recombination, the RAG complex binds at recombination signal sequences and creates double-strand breaks. In addition to this sequence-specific recognition of the RSS, the RAG complex has been shown to be a structure-specific nuclease, cleaving 3' overhangs and 3' flaps, and, more recently, 10 nucleotides (nt) bubble (heteroduplex) structures. Here, we assess the smallest size heteroduplex that core and full-length RAGs can cleave. We also test whether bubbles adjacent to a partial RSS are nicked any differently or any more efficiently than bubbles that are surrounded by random sequence. These points are important in considering what types and what size of non-B DNA structure that the RAG complex can nick, and this helps assess the role of the RAG complex in mediating lymphoid chromosomal translocations. We find that the smallest bubble nicked by the RAG complex is 3nt, and proximity to a partial or full RSS sequence does not affect the nicking by RAGs. RAG nicking efficiency increases with the size of the heteroduplex and is only about two-fold less efficient than an RSS when the bubble is 6nt. We consider these findings in the context of RAG nicking at non-B DNA structures in lymphoid chromosomal translocations.     

Fibroblast Activation Protein Overexpression and Clinical Implications in Solid Tumors: A Meta-Analysis

Objective

Fibroblast activation protein (FAP) plays a vital role in tumor invasion and metastasis. Previous studies have reported its prognostic value in different tumors. However, the results of these reports remain controversial. In this study, a meta-analysis was performed to clarify this issue.

Methods

A search of the PubMed, Embase and CNKI databases was conducted to analyze relevant articles. The outcomes included the relations between FAP expression and histological differentiation, tumor invasion, lymph node metastasis, distant metastasis and overall survival (OS). Sensitivity analysis by FAP expression in different cells and tumor types were further subjected to sensitivity analyses as subgroups. Pooled odds ratios (ORs) and hazard ratios (HRs) were evaluated using the random-effects model.

Results

The global analysis included 15 studies concerning various solid tumors. For global analysis, FAP overexpression in tumor tissue displayed significant associations with poor OS and tumor progression (OS: HR = 2.18, P = 0.004; tumor invasion: OR = 4.48, P = 0.007; and lymph node metastasis: OR = 3.80, P = 0.004). The subgroup analyses yielded two notable results. First, the relation between FAP overexpression and poor OS and tumor lymph node metastasis was closer in the patients with FAP expression in tumor cells. Second, the pooled analyses of colorectal cancers or pancreatic cancers all indicated that FAP overexpression was associated with a detrimental OS (HR: 1.72, P = 0.009; HR: 3.18, P = 0.005, respectively). The magnitude of this effect was not statistically significant compared with that in patients with non-colorectal cancers or non-pancreatic cancers. These analyses did not display a statistically significant correlation between FAP expression and histological differentiation and distant metastasis in all of the groups.

Conclusions

FAP expression is associated with worse prognosis in solid tumors, and this association is particularly pronounced if FAP overexpression is found in the tumor cells rather than the stroma.     

Micro-assembly of functionalized particulate monolayer on C18-derivatized SiO2 surfaces

This work describes a simple approach to immobilize functionalized colloidal microstructures onto a C(18)-coated SiO(2) substrate via specific or non-specific bio-mediated interactions. Biotinylated bovine serum albumin pre-adsorbed onto a C(18) surface was used to mediate the surface assembly of streptavidin-coated microbeads (2.8 microm), while a bare C(18) surface was used to immobilize anti-Listeria antibody-coated microbeads (2.8 microm) through hydrophobic interactions. For a C(18) surface pre-adsorbed with bovine serum albumin, hydrophobic polystyrene microbeads (0.8 microm) and positively charged dimethylamino microbeads (0.8 microm) were allowed to self-assemble onto the surface. A monolayer with high surface coverage was observed for both polystyrene and dimethylamino microbeads. The adsorption characteristics of Escherichia coli and Listeria monocytogenes on these microbead-based surfaces were studied using fluorescence microscopy. Both streptavidin microbeads pre-adsorbed with biotinylated anti-Listeria antibody and anti-Listeria antibody-coated microbeads showed specific capture of L. monocytogenes, while polystyrene and dimethylamino microbeads captured both E. coli and L. monocytogenes non-specifically. The preparation of microbead-based surfaces for the construction of microfluidic devices for separation, detection, or analysis of specific biological species is discussed.     

Essential role for cyclin D3 in granulocyte colony-stimulating factor-driven expansion of neutrophil granulocytes

The proliferation of neutrophil granulocyte lineage is driven largely by granulocyte colony-stimulating factor (G-CSF) acting via the G-CSF receptors. In this study, we show that mice lacking cyclin D3, a component of the core cell cycle machinery, are refractory to stimulation by the G-CSF. Consequently, cyclin D3-null mice display deficient maturation of granulocytes in the bone marrow and have reduced levels of neutrophil granulocytes in their peripheral blood. The mutant mice are unable to mount a normal response to bacterial challenge and succumb to microbial infections. In contrast, the expansion of hematopoietic stem cells and lineage-committed myeloid progenitors proceeds relatively normally in mice lacking cyclin D3, revealing that the requirement for cyclin D3 function operates at later stages of neutrophil development. Importantly, we verified that this requirement is specific to cyclin D3, as mice lacking other G(1) cyclins (D1, D2, E1, or E2) display normal granulocyte counts. Our analyses revealed that in the bone marrow cells of wild-type mice, activation of the G-CSF receptor leads to upregulation of cyclin D3. Collectively, these results demonstrate that cyclin D3 is an essential cell cycle recipient of G-CSF signaling, and they provide a molecular link of how G-CSF-dependent signaling triggers cell proliferation.     

治疗性单克隆抗体药物的现状及发展趋势

治疗性单克隆抗体药物经历了三十多年的发展,已经成为生物医药的最重要组成部分之一.在疾病治疗上具有广阔的应用前景,成功用于治疗肿瘤、自身免疫性疾病、感染性疾病和移植排斥反应等多种疾病.截至2012年已有29种治疗性单克隆抗体药物通过FDA审批并上市销售.治疗性单抗的安全性和有效性很大程度上由其作用的靶点决定,上市和在研的单抗药物有些靶向相同的靶点,有些有自己独特的作用靶点,新的作用靶点也在不断出现.以治疗性单抗的作用靶点为切入点,对目前上市销售和研发中的此类药物进行了简要总结.详述了肿瘤坏死因子α、白细胞分化抗原20、表皮生长因子受体及血管内皮生长因子等4种靶点的特点及相关单克隆抗体药物的情况,并对我国单抗药物的现状进行了分析,提出未来发展对策.