Isolation and sequence of the MIG1 homologue from the yeast Candida utilis

The Mig1p repressor from the food yeast Candida utilis has been isolated using a homologous PCR hybridization probe. This probe was amplified with two sets of degenerate primers designed on the basis of highly conserved motifs in the DNA-binding region (zinc-finger domain) from yeast Mig1p and fungi CreA repressors. The cloned gene was sequenced and found to encode a polypeptide of 345 amino acids which shows significant identity with other yeast and fungus repressors in the DNA-binding domain and also with the yeast Mig1 proteins in the C-terminal region (effector domain). The MIG1 repressor gene from C. utilis was able to complement functionally the mig1 mutation of S. cerevisiae. The sequence presented here has been deposited in the EMBL data library under Accession No. AJ277830.     

Contribution of starter culture to the sensory characteristics of fermented Almagro eggplants

Trial fermentations were performed using three experimental starter cultures with a view to selecting the most appropriate starter for use in the manufacture of Almagro eggplants. The lactic acid bacterial strains used in the starters had previously been isolated from spontaneous fermentations. The combined action of the obligate heterofermentative species Lactobacillus brevis and the facultative heterofermentative species L. plantarum yielded Almagro eggplants with sensory properties preferred by panelists. Conversely, another obligate heterofermentative species, namely, L. fermentum, present in certain starter formulations tested, appeared to encounter difficulty growing during fermentation and exerted little influence on the sensory characteristics of the eggplants produced.     

最优加权组合模型在边坡变形预测中的应用

利用某岩质边坡2002年-2011年的变形监测资料,结合区域地质与气象背景,运用莱茵达准则选定有效的监测数据,分别建立了GM(1,1)模型和趋势曲线预测模型;最后,基于最优加权组合原理,建立了边坡变形的最优加权组合模型。运用组合模型对该岩质边坡的变形进行了拟合和变形预测,模拟变形趋势与实际变形趋势对比结果表明,组合模型的预测精度高于任何单一模型的拟合精度,证明该组合模型合理、可靠。     

珠海350 kt/a 精对苯二甲酸装置开工建设

产能 35 0ｋｔ/ａ的精对苯二甲酸 (ＰＴＡ)装置于 2 0 0 0年 11月 13日在珠海市临港工业区正式动工兴建 ,计划于 2 0 0 2年竣工。该项目将由Ａｍｏｃｏ 珠海化工公司拥有并经营。该公司是ＢＰＡｍｏｃｏ、珠海富华集团和中国化纤总公司 3年前成立的合资公司 ,ＢＰＡｍｏｃｏ持股 80 % ,富华集团持股15 % ,中国化纤总公司持股 5 %。该合资项目总投资达 3.6亿美元。我国现有ＰＴＡ装置共 12套 ,生产能力达 2 0 86ｋｔ/ａ。国内ＰＴＡ生产主要用于聚酯纤维 ,其消费量约占总产量的90 %。随着我国电子工业、汽车工业、食品包装等相关行业的飞速发…     

近期国内乙烯项目扩建消息

20 0 0年 12月 8日 ,改造后的中原 180ｋｔ/ａ乙烯装置生产出合格乙烯 ,标志着由中原乙烯 140ｋｔ/ａ改扩为 180ｋｔ/ａ的乙烯改造取得圆满成功。该工程总体改造投入为 3.6亿元人民币 ,按目前产品售价计算 ,每年可实现 5～ 6亿元人民币的销售收入 ,其重大设备供应首次由国内承担 ,是中国石化集团公司小乙烯改造的三大试点之一 ,对其它小乙烯改造具有示范作用。国家发展计划委员会批准了福建 6 0 0ｋｔ/ａ乙烯项目建议书。该项目包括建一套 6 0 0ｋｔ/ａ乙烯装置、一套 45 0ｋｔ/ａ聚乙烯装置和一套 30 0ｋｔ/ａ聚丙烯装置 ,总耗资为 133亿元…     

Effect of transport time and ageing on aspects of beef quality

Forty-eight bulls were transported by road in groups of eight for approximately 30 min, 3 or 6 h in two replicates. After slaughter, steaks from the longissimus dorsi thoracis of all transported animals were analysed in terms of pH, water-holding capacity, myoglobin concentration, texture at 7 and 14 days of ageing (compression and Warner-Bratzler analyses) and colour of the same surface of meat cut at 24 h post-mortem and allowed to bloom for 24 h and 7 d (L^*a^*b^*, chroma and hue). The myofibrillar resistance of the meat from animals transported 30 min was significantly greater at 20% compression (P<0.05). The maximum load and a^*b^* and chroma were all lower for meat aged 14 days.     

Structural characterization of chromosome I size variants from a natural yeast strain

Many yeast strains isolated from the wild show karyotype instability during vegetative growth, with rearrangement rates of up to 10(-2) chromosomal changes per generation. Physical isolation and analysis of several chromosome I size variants of one of these strains revealed that they differed only in their subtelomeric regions, leaving the central 150 Kb unaltered. Fine mapping of these subtelomeric variable regions revealed gross alterations of two very similar loci, FLO1 and FLO9. These loci are located on the right and left arms, respectively, of chromosome I and encompass internal repetitive DNA sequences. Furthermore, some chromosome I variants lacking the FLO1 locus showed evidence of recombination at a DNA region on their right arm that is enriched in repeated sequences, including Ty LTRs. We propose that repetitive sequences in many subtelomeric regions in S. cerevisiae play a key role in karyotype hypervariability. As these regions encode several membrane-associated proteins, subtelomeric plasticity may allow rapid adaptive changes of the yeast strain to specific substrates. This pattern of semi-conservative chromosomal rearrangement may have profound implications, both in terms of evolution of wild strains and for biotechnological processes.     

As, Hg, and Se flue gas sampling in a coal-fired power plant and their fate during coal combustion

As, Hg, and Se are the most volatile elements in the flue gas from a coal-fired power plant. Significant amounts of these elements cause an undesired direct gaseous emission, which leads to a serious environmental health risk. The main focus of this study is to evaluate the possibility of simultaneous sampling of these volatile elements using an accurate official method for Hg (the most volatile element). A study of As, Hg, and Se emissions from a 1400 MW coal-fired power plant equipped with electrostatic precipitators (ESPs) was carried out for the combustion of a mixture of two types of coal. Simultaneous sampling of coal, bottom ash, fly ash, flue gas, and particles associated with the gas phase has been performed. Flue gas has been sampled by the Ontario Hydro Method Sampling Train, an ASTM method for Hg speciation. This sampling method was tested for As and Se sampling. As and Se determinations have been performed by HG-AAS, and Hg has been determined by CV-AAS. The results were used to examine the following: overall mass balances, relative distribution of these elements in the coal-fired power plant; As, Hg, and Se concentrations in coal and combustion residues; and predominant oxidation state for Hg in flue gas. The mass balances obtained for As, Hg, and Se were satisfactory in all cases; nevertheless, relative enrichment values in fly ash for As and Se were low; therefore, we concluded that As sampling in flue gas can be conducted by application of the Ontario Hydro Method; nevertheless Se released in the gas phase is not completely collected by this sampling train. Application of this sampling method allowed for performance of Hg speciation. The results indicated that Hg(II) was the predominant species in flue gas. It has also been proved that 24%, more than 99.8%, and 90% for As, Hg, and Se in the stack emissions, respectively, were in the gaseous phase.     

Correlation between DNA synthesis in the second, third and fourth generations of spermatogonia and the occurrence of apoptosis in both spermatogonia and spermatocytes

In the seminiferous epithelium, both DNA synthesis and apoptosis occur at equivalent stages in various species, with apoptosis taking place mainly at the same stages as DNA replication in the second, third and fourth spermatogonial generations. As preservation of the cellular associations found at these stages may have some functional significance, it is important to determine whether there is a correlation between these cellular events. In this study, pairs of immunoperoxidase-stained adjacent testis sections from rats, mice, rabbits and cats in which either bromodeoxyuridine incorporated into the newly synthesized DNA strand (BrdU labelling) or DNA 3' end labelling of the apoptotic DNA fragments (TUNEL assay) were detected were compared. In addition, both events were analysed in double-labelled sections. These two methods revealed a clear correlation between the occurrence of DNA replication in the second to fourth generations of spermatogonia and most physiological apoptosis taking place in both spermatogonia and spermatocytes in the three different mammalian orders (Rodentia, Lagomorpha and Carnivora). This correlation may result from the synchronization of mitotic spermatogonial and meiotic spermatocyte cell cycle checkpoints operating at these stages.