观看、在场与公共视觉伦理影响：论当代景观空间的剧场性

当风景园林与戏剧艺术相关联时,并非仅指代表象化的、空洞无味的形式语言,而是可以具备更丰富、更深层的关系。对深层关联的剖析和揭示,有助于从多个视角进行学科认知和帮助设计实践。将“剧场性”一词置于风景园林学科语境时,可以从 “在场”和“观看”两个层面进行解读：形式向度上,它以观者身体的出席为实现前提;内涵向度上,它强调观看行为背后的意图与观念。不仅如此,在工业与科技崛起、社会关系产生变革的时代背景下,公共空间关系也相应变化,公共视觉的建构与传播成为实现社会伦理影响的重要手段。相应地,公共景观空间作为承载全民性“在场”的“观看”行为的剧场性空间,需要考虑如何通过营造手段实现大众意识的引导。基于以上内涵关联,以“剧场性”作为切入视角便会发现,社会公正、审美引导和潜在信息传播可以被提炼为当代景观空间营造中公共视觉伦理转向的3个关键词。它们的价值在物质空间中以视觉话语的形式体现,而隐含在其后的公民权利宣言和自然伦理教育与引导,则以无形的方式传播到更远的地方。     

分离自杭子梢等宿主根瘤的30株菌的结瘤特性的研究

对分离自杭子梢、菜豆和决明等宿主根瘤、处于Agrobacterium系统发育分支、DNA-DNA杂交与A.rubi的相似性达到100%的30株土壤杆菌,分属于Agrobacterium、Bradyrhizobium、Mesorhizobium、Rhizobium和Sinorhizobium 5个属的12个参比菌株。nodA PCR的结果表明,30株供试菌中扩增不出nodA,即没有结瘤性。以Sinorhizobium meliloti USDA1002T的nodA做探针对所提取的细菌总DNA进行斑点杂交,在65℃-68℃严谨洗膜条件下,该探针只能与同种的根瘤菌进行杂交,不能与其它属的根瘤菌或土壤杆菌杂交,初步推测共同结瘤基因nodA探针只能对种内根瘤菌的结瘤性进行鉴定。     

GSTM1 and GSTT1 Null Polymorphisms and Childhood Acute Leukemia Risk: Evidence from 26 Case-Control Studies

Several molecular epidemiological studies have been conducted to examine the association between glutathione S-transferase mu-1 (GSTM1) and glutathione S-transferase theta-1 (GSTT1) null polymorphisms and childhood acute leukemia; however, the conclusions remain controversial. We performed an extensive meta-analysis on 26 published case-control studies with a total of 3252 cases and 5024 controls. Crude odds ratios (ORs) with 95% confidence interval were used to assess the strength of association between childhood acute leukemia risk and polymorphisms of GSTM1 and GSTT1. With respect to GSTM1 polymorphism, significantly increased risk of childhood acute leukemia was observed in the overall analysis (OR = 1.30; 95%CI, 1.11-1.51). Furthermore, a stratification analysis showed that the risk of GSTM1 polymorphism are associated with childhood acute leukemia in group of Asians (OR = 1.94; 95%CI, 1.53-2.46), Blacks (OR = 1.76; 95%CI, 1.07-2.91), ALL (OR = 1.33; 95%CI, 1.13-1.58), ‘< 100 cases and <100 controls’ (OR = 1.79; 95%CI, 1.21-2.64), ‘≥ 100 cases and ≥ 100 controls’ (OR = 1.25; 95%CI, 1.02-1.52), and population-based control source (OR = 1.40; 95%CI, 1.15-1.69). With respect to GSTT1 polymorphism, significant association with childhood acute leukemia risk was only found in subgroup of Asian. This meta-analysis supports that GSTM1 null polymorphism is capable of causing childhood acute leukemia susceptibility.     

Enhancing the Thermotolerance of Isochrysis zhangjiangensis Through Co-culturing With Algoriphagus marincola

Marine Biotechnology - Isochrysis zhangjiangensis is an important microalgal species used as bait in aquaculture. However, its optimal cultivation temperature is around 25&nbsp;°C,...     

Protein engineering,cofactor engineering,and surface display engineering to achieve whole-cell catalytic production of chondroitin sulfate A

Chondroitin sulfate A (CSA) is a valuable glycosaminoglycan that has great market demand. However, current synthetic methods are limited by requiring the expensive sulfate group donor 3′-phosphoadenosine-5′-phosphosulfate (PAPS) and inefficient enzyme carbohydrate sulfotransferase 11 (CHST11). Herein, we report the design and integration of the PAPS synthesis and sulfotransferase pathways to realize whole-cell catalytic production of CSA. Using mechanism-based protein engineering, we improved the thermostability and catalytic efficiency of CHST11; its T_m and half-life increased by 6.9°C and 3.5 h, respectively, and its specific activity increased 2.1-fold. Via cofactor engineering, we designed a dual-cycle strategy of regenerating ATP and PAPS to increase the supply of PAPS. Through surface display engineering, we realized the outer membrane expression of CHST11 and constructed a whole-cell catalytic system of CSA production with an 89.5% conversion rate. This whole-cell catalytic process provides a promising method for the industrial production of CSA.     

Supramolecular CRISPR-OFF switches with host–guest chemistry

CRISPR (Clustered Regularly Interspaced Short Palindromic Repeat) technology is a powerful tool in biology and medicine. However, the safety and application of this technology is hampered by excessive activity of CRISPR machinery. It is particularly important to develop methods for switching off CRISPR activity in human cells. The current study demonstrates the concept of supramolecular CRISPR-OFF switches by employing host-guest chemistry. We demonstrate that the CRISPR systems show considerable tolerance to adamantoylation on guide RNAs (gRNAs), whereas supramolecular complexation tremendously affects the function of adamantoyl gRNAs. Host–guest chemistry is demonstrated to be novel and effective tools to reduce unwanted excessive activities of CRISPR complexes in human cells. This work indicates considerable potential of supramolecular strategy for controlling and enhancing CRISPR systems.     

Are variants in the CAPN10 gene related to risk of type 2 diabetes? A quantitative assessment of population and family-based association studies

The calpain-10 gene (CAPN10) on chromosome 2q37.3 was the first candidate gene for type 2 diabetes (T2D) identified through a genomewide screen and positional cloning. One polymorphism (UCSNP-43: G-->A) and a specific haplotype combination defined by three polymorphisms (UCSNP-43, -19, and -63) were linked to an increased risk of T2D in several populations. To quantitatively assess the collective evidence for the effects of CAPN10 on risk of T2D, we conducted a meta-analysis of both population-based and family-based association studies. We retrieved data from the MEDLINE, PubMed, and Online Mendelian Inheritance in Man databases, as well as from other relevant reports and abstracts published up to July 2003. From a total of 26 studies with primary data (21 population-based studies: 5,013 cases and 5,876 controls; 5 family-based studies: 487 parent-offspring trios), we developed a summary database that contains variables of study design, study population/ethnicity, specific polymorphisms and haplotype combinations in CAPN10, and diabetes-related metabolic phenotypes. For population-based studies, we used both fixed-effects and random-effects models to calculate the pooled odds ratio (OR) and 95% confidence interval (CI) for the associations of CAPN10 genotypes with the risk of T2D. We also calculated weighted mean differences for the associations between CAPN10 and diabetes-related quantitative traits. Under either an additive or a dominant effect model, we found no statistically significant relation between CAPN10 genotypes in the UCSNP-43 locus and T2D risk. However, under a recessive model, individuals homozygous for the common G allele had a statistically significant 19% higher risk of T2D than carriers of the A allele (OR 1.19; 95% CI 1.07-1.33). The association between the 112/121 haplotype combination and T2D risk appeared to be overestimated by several initial small studies with positive findings (OR 1.38; 95% CI 1.04-1.84). After we removed these initial studies, this association became nonsignificant (OR 1.11; 95% CI 0.91-1.35). Moreover, we found no evidence for the associations between the UCSNP-43 G/G genotype and the 112/121 haplotype combination and metabolic phenotypes. Our meta-analysis of family-based studies showed only an overtransmission of the rare allele C in UCSNP-44 from heterozygous parents to their affected offspring with T2D. Our analysis indicates that inadequate statistical power, racial/ethnic differences in frequencies of alleles, haplotypes and haplotype combinations, potential gene-gene or gene-environment interactions, publication bias, and multiple hypothesis testing may contribute to the significant heterogeneity in previous studies of CAPN10 and T2D. Our findings also suggest that both large-scale, well-designed association studies and functional studies are warranted to either reliably confirm or conclusively refute the initial hypothesis regarding the role of CAPN10 in T2D risk.     

Oxidation inhibits amyloid fibril formation of transthyretin

The role of amino acid side chain oxidation in the formation of amyloid assemblies has been investigated. Chemical oxidation of amino acid side chains has been used as a facile method of introducing mutations on protein structures. Oxidation promotes changes within tertiary contacts that enable identification of residues and interactions critical in stabilizing protein structures. Transthyretin (TTR) is a soluble human plasma protein. The wild-type (WT) and several of its variants are prone to fibril formation, which leads to amyloidosis associated with many clinical syndromes. The effects of amino acid side chain oxidations were investigated by comparing the kinetics of fibril formation of oxidized and unoxidized proteins. The WT and V30M TTR mutant (valine 30 substituted with methionine) were allowed to react over a time range of 10 min to 12 h with hydroxy radical and other reactive oxygen species. In these timescales, up to five oxygen atoms were incorporated into WT and V30M TTR proteins. Oxidized proteins retained their tetrameric structures, as determined by cross-linking experiments. Side chain modification of methionine residues at position 13 and 30 (the latter for V30M TTR only) were dominant oxidative products. Mono-oxidized and dioxidized methionine residues were identified by radical probe mass spectometry employing a footprinting type approach. Oxidation inhibited the initial rates and extent of fibril formation for both the WT and V30M TTR proteins. In the case of WT TTR, oxidation inhibited fibril growth by approximately 76%, and for the V30M TTR by nearly 90%. These inhibiting effects of oxidation on fibril growth suggest that domains neighboring the methionine residues are critical in stabilizing the tetrameric and folded monomer structures.     

Quantitative determination of decitabine incorporation into DNA and its effect on mutation rates in human cancer cells

Decitabine (5-aza-2′-deoxycytidine) is a DNA methyltransferase inhibitor and an archetypal epigenetic drug for the therapy of myeloid leukemias. The mode of action of decitabine strictly depends on the incorporation of the drug into DNA. However, DNA incorporation and ensuing genotoxic effects of decitabine have not yet been investigated in human cancer cell lines or in models related to the approved indication of the drug. Here we describe a robust assay for the quantitative determination of decitabine incorporation rates into DNA from human cancer cells. Using a panel of human myeloid leukemia cell lines we show appreciable amounts of decitabine incorporation that closely correlated with cellular drug uptake. Decitabine incorporation was also detectable in primary cells from myeloid leukemia patients, indicating that the assay is suitable for biomarker analyses to predict drug responses in patients. Finally, we also used next-generation sequencing to comprehensively analyze the effects of decitabine incorporation on the DNA sequence level. Interestingly, this approach failed to reveal significant changes in the rates of point mutations and genome rearrangements in myeloid leukemia cell lines. These results indicate that standard rates of decitabine incorporation are not genotoxic in myeloid leukemia cells.