Simultaneous suppression of multiple genes by single transgenes. Down-regulation of three unrelated lignin biosynthetic genes in tobacco

Many reports now describe the manipulation of plant metabolism by suppressing the expression of single genes. The potential of such work could be greatly expanded if multiple genes could be coordinately suppressed. In the work presented here, we test a novel method for achieving this by using single chimeric constructs incorporating partial sense sequences for multiple genes to target suppression of two or three lignin biosynthetic enzymes. We compare this method with a more conventional approach to achieving the same end by crossing plants harboring different antisense transgenes. Our results indicate that crossing antisense plants is less straightforward and predictable in outcome than anticipated. Most progeny had higher levels of target enzyme activity than predicted and had lost the expected modifications to lignin structure. In comparison, plants transformed with the chimeric partial sense constructs had more consistent high level suppression of target enzymes and had significant changes to lignin content, structure, and composition. It was possible to suppress three target genes coordinately using a single chimeric construct. Our results indicate that chimeric silencing constructs offer great potential for the rapid and coordinate suppression of multiple genes on diverse biochemical pathways and that the technique therefore deserves to be adopted by other researchers.     

A new Saccharomyces cerevisiae strain with a mutant Smt3-deconjugating Ulp1 protein is affected in DNA replication and requires Srs2 and homologous recombination for its viability

The Saccharomyces cerevisiae Srs2 protein is involved in DNA repair and recombination. In order to gain better insight into the roles of Srs2, we performed a screen to identify mutations that are synthetically lethal with an srs2 deletion. One of them is a mutated allele of the ULP1 gene that encodes a protease specifically cleaving Smt3-protein conjugates. This allele, ulp1-I615N, is responsible for an accumulation of Smt3-conjugated proteins. The mutant is unable to grow at 37 degrees C. At permissive temperatures, it still shows severe growth defects together with a strong hyperrecombination phenotype and is impaired in meiosis. Genetic interactions between ulp1 and mutations that affect different repair pathways indicated that the RAD51-dependent homologous recombination mechanism, but not excision resynthesis, translesion synthesis, or nonhomologous end-joining processes, is required for the viability of the mutant. Thus, both Srs2, believed to negatively control homologous recombination, and the process of recombination per se are essential for the viability of the ulp1 mutant. Upon replication, mutant cells accumulate single-stranded DNA interruptions. These structures are believed to generate different recombination intermediates. Some of them are fixed by recombination, and others require Srs2 to be reversed and fixed by an alternate pathway.     

磁化水对小麦种子萌发、幼苗生长和生理特性的生物学效应

为研究磁化水对作物的生物学效应,本文详细分析了磁化水处理对小麦种子萌发、幼苗生长和生理特性的影响。研究结果显示：磁化水处理小麦的种子发芽参数与对照相比无显著差异;磁化水处理对小麦的株高、根长、地上部和根部鲜重等生长参数也无显著影响;同样,磁化水处理在叶片色素含量、可溶性糖、可溶性蛋白质含量、含水量、细胞汁液渗透势等重要生理特征参数方面也未显示出显著差异。此外,磁化水并未显著影响小麦叶片的光合作用。综上所述,磁化水处理对小麦种子萌发和幼苗生长无明显的生物学效应。     

大剂量HBsAg 对HBV 转基因小鼠T 细胞免疫调节的研究

目的:研究大剂量HBsAg对HBV转基因小鼠其T细胞免疫效果的影响。方法:用大剂量血源性HBsAg免疫HBV转基因小鼠,采用ELISA方法观察转基因小鼠所诱生的HBsAg特异性Th1类细胞因子的水平,ELISPOT方法检测不同免疫方案对小鼠HBsAg特异性分泌IFN-γT细胞数量的影响,同时检测对小鼠淋巴细胞增殖的影响。结果:HBsAg组免疫后脾细胞产生的Th1类细胞因子(IFN-γ、IL-2)、HBsAg特异性分泌IFN-γT细胞及T细胞增殖水平较对照组显著增加(P<0.05)。结论:大剂量的HBs-Ag可以诱导乙肝转基因小鼠产生高水平Th1类细胞因子并打破免疫耐受。     

Metabolites secreted by human atherothrombotic aneurysms revealed through a metabolomic approach

Abdominal aortic aneurysm (AAA) is perma-nent and localized dilation of the abdominal aorta. Intraluminal thrombus (ILT) is involved in evolution and rupture of AAA. Complex biological processes associated with AAA include oxidative stress, proteolysis, neovascularization, aortic inflammation, cell death, and extracellular matrix breakdown. Biomarkers of growth and AAA rupture could give a more nuanced indication for surgery, unveil novel pathogenic pathways, and open possibilities for pharmacological inhibition of growth. Differential analysis of metabolites released by normal and pathological arteries in culture may help to find molecules that have a high probability of later being found in plasma and start signaling processes or be useful diagnostic/prognostic markers. We used a LC-QTOF-MS metabolomic approach to analyze metabolites released by human ILT (divided into luminal and abluminal layers), aneurysm wall (AW), and healthy wall (HW). Statistical analysis was used to compare luminal with abluminal ILT layer, ILT with AW, and AW with HW to select the metabolites exchanged between tissue and external medium. Identified compounds are related to inflammation and oxidative stress and indicate the possible role of fatty acid amides in AAA. Some metabolites (e.g., hippuric acid) had not been previously associated to aneurysm, others (fatty acid amides) have arisen, indicating a very promising line of research.     

Principles and practice in ethical review of animal experiments across Europe: summary of the report of a FELASA working group on ethical evaluation of animal experiments

This paper summarizes a more detailed report produced by the Federation of European Laboratory Animal Science Associations (FELASA 2005), which describes and explores a set of principles for the conduct of ethical review of laboratory animal use. It presents a synopsis of results from a questionnaire that elicited information on how each of 20 countries represented in FELASA currently approaches such ethical review. This information suggests that, although local practices differ, there is an emerging consensus on the key elements that any ethical review process should involve. Drawing on the questionnaire findings, this summary also includes a brief discussion to support and amplify a series of recommendations, covering the objectives of ethical review; legal requirements; the scope of work reviewed and the 'level' at which review is approached; general principles for the organization of ethical review processes; the factors considered in the review; needs for ongoing review after initial authorization; participants in the review process; wider impacts of the review process; and strategies that can help to ensure quality and consistency of review outcomes. For further information and examples of current practice, as well as more detailed discussion to support the recommendations, readers are urged to refer to the complete report, available at http://www.lal.org.uk/pdffiles/FELASA_ethics_FULL_Report. pdf or via: http://www.felasa.eu/recommendations.htm.     

用地高辛标记探针检测基因工程人β干扰素制品中的外源DNA

基因工程人β干扰素工程菌经发酵培养、纯化后获得纯的制品,采用斑点杂交技术,用非放射性地高辛标记超声裂解的全工程菌ＤＮＡ作为探针,检测基因工程人β干扰素纯品,结果显示：基因工程人β干扰素纯品中的外源ＤＮＡ含量小于１００ｐｇ／剂。     

Evidence of Uncoupling between Renal Dysfunction and Injury in Cardiorenal Syndrome: Insights from the BIONICS Study

Objective

The objective of the study was to assess urinary biomarkers of renal injury for their individual or collective ability to predict Worsening renal function (WRF) in patients with acutely decompensated heart failure (ADHF).

Methods

In a prospective, blinded international study, 87 emergency department (ED) patients with ADHF were evaluated with biomarkers of cardiac stretch (B type natriuretic peptide [BNP] and its amino terminal equivalent [NT-proBNP], ST2), biomarkers of renal function (creatinine, estimated glomerular filtration rate [eGFR]) and biomarkers of renal injury (plasma neutrophil gelatinase associated lipocalin [pNGAL], urine kidney injury molecule-1 [KIM-1], urine N-acetyl-beta-D-glucosaminidase [NAG], urine Cystatin C, urine fibrinogen). The primary endpoint was WRF.

Results

26% developed WRF; baseline characteristics of subjects who developed WRF were generally comparable to those who did not. Biomarkers of renal function and urine biomarkers of renal injury were not correlated, while urine biomarkers of renal injury correlated between each other. Biomarker concentrations were similar between patients with and without WRF except for baseline BNP. Although plasma NGAL was associated with the combined endpoint, none of the biomarker showed predictive accuracy for WRF.

Conclusions

In ED patients with ADHF, urine biomarkers of renal injury did not predict WRF. Our data suggest that a weak association exists between renal dysfunction and renal injury in this setting (Clinicaltrials.gov NCT#0150153).