Production of L(+)-lactic acid with Rhizopus oryzae immobilized in polyurethane foam cubes

Summary Polyurethane foam cubes were employed as carriers to immobilize Rhizopus oryzae for L(+)-lactic acid production. The immobilizing capacity reached 450 g-fresh cell/l-cube. The production rate of L(+)-lactic acid could be threefold increased by using the immobilized R. oryzae. The immobilized cells could be steadily used in repetitive fermentations for more than 10 batches.     

Elongation factor 1α genes of the red alga Porphyra purpurea include a novel, developmentally specialized variant

The life cycle of the red alga Porphyra purpurea alternates between two morphologically distinct phases: a shell-boring, filamentous sporophyte and a free-living, foliose gametophyte. From a subtracted cDNA library enriched for sporophyte-specific sequences, we isolated a cDNA encoding an unusual elongation factor 1 (EF-1) that is expressed only in the sporophyte. A second EF-1 gene that is expressed equally in the sporophyte and the gametophyte was isolated from a genomic library. These are the only EF-1 genes detectable in P. purpurea. The constitutively expressed gene encodes and EF-1 very similar to those of most eukaryotes. However, the sporophyte-specific EF-1 is one of the most divergent yet described, with nine insertions or deletions ranging in size from 1 to 26 amino acids. This is the first report of a developmental stage-specific EF-1 outside of the animal kingdom and suggests a fundamental role for EF-1 in the developmental process.     

Flooding-induced membrane damage, lipid oxidation and activated oxygen generation in corn leaves

Flooding effects on membrane permeability, lipid peroxidation and activated oxygen metabolism in corn (Zea mays L.) leaves were investigated to determine if activated oxygens are involved in corn flooding-injury. Potted corn plants were flooded at the 4-leaf stage in a controlled environment. A 7-day flooding treatment resulted in a significant increase in chlorophyll breakdown, lipid peroxidation (malondialdehye content), membrane permeability, and the production of superoxide (O ₂ ^- ) and hydrogen peroxide (H₂O₂) in corn leaves. The effects were much greater in older leaves than in younger ones. Spraying leaves with 8-hydroxyquinoline (an O ₂ ^- scavenger) and sodium benzoate (an .OH scavenger) reduced the oxidative damage and enhanced superoxide dismutase (SOD) activity. A short duration flooding treatment elevated the activities of SOD, catalase, ascorbate peroxidase (AP), and glutathione reductase (GR), while further flooding significantly reduced the enzyme activities but enhanced the concentrations of ascorbic acid and reduced form glutathione (GSH). It was noted that the decline in SOD activity was greater than that in H₂O₂ scavengers (AP and GR). The results suggested that O ₂ ^- induced lipid peroxidation and membrane damage, and that excessive accumulation of O ₂ ^- is due to the reduced activity of SOD under flooding stress.     

融合株SPSC发酵生产酒精的工艺研究 Ⅰ.絮凝速率、发酵过程的最适温度和pH值

酿酒酵母属(S. cereviae)变异株和粟酒裂殖酵母属(S. pombe)变异株进行属间原生质体融合得到融合株SPSC,该融合株比S. cereviae具有强的自身絮凝能力。以葡萄糖浓度150g/L的底物在30～44℃的温度范围内进行摇瓶厌氧发酵,获得最佳温度范围为34～38℃,最高发酵温度为40℃。在有效容积2.35L悬浮床反应器中,在pH值3.0～5.0范围内进行连续发酵,获得最适发酵pH为3.5～4.5。     

Characterization of a Kinesin-Related Gene ATSV, within the Tuberous Sclerosis Locus (TSC1) Candidate Region on Chromosome 9Q34

In the search for candidate genes for the tuberous sclerosis (TSC1) disease locus on chromosome 9q34, we have isolated an overlapping series of 22 plasmid and phage cDNA clones covering nearly 7 kb and with an open reading frame of 5070 bp encoding a protein of 1690 amino acids. The putative protein product is a member of the kinesin superfamily and is homologous to the mouse KIF1A and theCaenorhabditas elegansunc-104 genes. Both KIF1A and unc-104 function in the anterograde axonal transport of synaptic vesicles. The human homolog is therefore termed H-ATSV (axonal transporter of synaptic vesicles, HGMW-approved nomenclature ATSV) Screening of DNA from 107 tuberous sclerosis patients and 80 unaffected individuals with H-ATSV cDNA probes by pulsed-field gel electrophoresis/Southern blotting following digestion by rare-cutting methylation-sensitive restriction enzymes showed variant banding patterns in three patients with tuberous sclerosis. However, further analysis indicated that these variant fragments represent a rare polymorphism probably associated with methylation of clustered restriction sites. There is no evidence to support H-ATSV as a candidate gene for TSC1.     

表达HSV－2 gD基因的重组痘苗病毒保护小鼠对抗致死量HSV病霉攻击

利用ＰＣＲ方法对单纯疱疹病毒Ⅱ型糖蛋白Ｄ（ＨＳＶ－２ｇＤ）基因进行了修饰,在其５＇端删去约５００ｂｐ的非编码区,仅保留ＡＴＧ上游７个ｂｐ。将修饰后的ＨＳＶ－２ｇＤ基因插入到带有痘苗病毒天坛株ＴＫ基因区段的痘苗表达质粒ｐＪＳＡ１１７５,置于痘苗病毒Ｐ７．５ｋ早／晚期启动子控制下。将此重组质粒用脂质体Ｌｉｐｏｆｅｃｔｉｎ方法转染已受野型ＴＫ￣＋痘苗病毒天坛株感染的ＴＫ￣－１４３细胞,通过同源重组机制和标志基因ＬａｃＺ产物的蓝斑显色作用,以及ＢｕｄＲ试剂对ＴＫ表型的选择压力,筛选出整合有ＨＳＶ－２ｇＤ基因的重组痘苗病毒。Ｓｏｕｔｈｅｍ杂交表明,ＨＳＶ－２ｇＤ基因已正确地插入痘苗病毒ＴＫ基因区内;间接免疫荧光检测显示,ＨＳＶ－２ｇＤ蛋白已得到有效表达,且主要分布于细胞膜。重组病毒免疫家兔可产生明显的抗ＨＳＶ－２ｇＤ中和抗体。用重组病毒免疫小鼠,３周后可使９４％（１７／１８）的小鼠对抗ＨＳＶ－２的致死量攻击,表明重组病毒具有明显的免疫保护作用。     

武汉东湖水生植被及其恢复途径探讨

１９９２～１９９３年对武汉东湖三个主要湖区（郭郑湖、汤林湖和牛巢湖）水生植被的调查表明,该湖区共有水生植物３２种,优势种为大茨藻、狐尾藻、苦草和菱。金鱼藻呈不断扩大的趋势。植被类型可分为１１个群丛,植被面积约为０．６５ｋｍ￣２,总生物量为１２３６．３９ｔ（湿重）,植被带状分布仅见于汤林湖北部和其他部分湖汊。汤林湖和牛巢湖水生植被正处于自然恢复演替阶段。     

混合氨基酸含量测定新方法

介绍用交流示波极谱滴定法测混合氨基酸的含量。在ＫＣｌ底液中,利用ＨＣＨＯ将－ＮＨ２封闭,用ＫＯＨ标准液滴定,ＨＣＨＯ同时做指示剂,以极谱图形的敏锐变化指示终点的到过,测定结果准确。