生产菌DAB啤酒酵母选育技术研究

生产性状发生退化的DAB酵母,采用30％致死率的紫外线处理,经高糖培养基筛选及单细胞分离等手段,得到一株性能优良的啤酒生产酵母菌种。     

Bacterial and parasitic pathogens in cultured common dentex, Dentex dentex L.

A bacteriological and parasitological study on cultured common dentex, Dentex dentex L., was conducted in a 2-year survey. Two different groups of fish were studied: (1) sampled only when mortalities occurred; and (2) sampled periodi-cally from 10days post-hatch until the juvenile stage. In both groups, peaks of mortalities coincided with high water temperatures. The same parasites were detected in both groups, except Ichthyophonus sp., which was identified only in the trunk kidney of fish from group 1. Two myxosporeans, Ceratomyxa sp. and Lepthotheca sp., were found in the bile and the trunk kidney, respectively. Epitheliocystis infection was also very frequent in the gills. An unidentified microsporidium, which was found in the liver, occurred very infrequently. Vibrio harveyi was dominant in samples from diseased animals (79%) and clearly associated with mortalities. It was not detected in water or larval homogenates. A high percentage (60%) of the isolates of this species were sorbitol positive. Other less frequently occurring bacteria were V. alginolyticus and Photobacterium (V.) damselae. The disease conditions found in common dentex were considered to be multifactorial in origin.     

桐竹混交培育泡桐单板材的研究

利用生物种群共生的竞争作用，通过３种密度的桐竹混交试验，研究在复层混交条件下培育泡桐单板材的可能性。结果表明，桐竹混交在沿海地区有较强的抗风倒能力，能显著地提高泡桐的枝下高和主干高，使树干形数和圆满度显著增大，泡桐的单板材出材量提高５０％以上。     

Monokaryons Fruiting and Fruit body color of Flammulina velutipes

Thirteen kinds of yellow and three kinds of white monokaryons were isolated from mycelium of eight Flammulina velutipes strains using the monokaryon protoplast technique. Of these, five yellow and two white monokaryons produced monokaryotic fruit bodies. Clear differences were observed in the color of the different yellow monokaryotic fruit bodies, as well as between the pilei and stipes of individual yellow monokaryotic fruit bodies, suggesting that the yellow color is under the control of multiple alleles.     

创新管理打造牧羊精品

江苏牧羊集团的前身是1967年建立的邗江粮食机械厂，是原商业部最早定点专业生产饲料机械的厂家，经过近40年的发展，现已成为集产品研发、制造、工程设计、安装与服务于一体的粮油饲料机械企业。     

行列式元素的两个要素

本文指出行列式的元素有数值和下标(行标和列标)两个要素。行列式的许多定理实际上描述了行列式的值与两要素的关系。并指出:在一些定理的证明中,突出行列式元素的两个要素,可使证明思路清晰,简单明了,容易理解。     

转基因棉对高抗Bt棉棉铃虫生长发育及活动频率的影响

以敏感品系棉铃虫在苏棉12和玉米上的生长发育及活动频率为对照,研究了新棉33B对高抗Bt棉棉铃虫生长发育及活动频率的影响。结果表明,高抗品系棉铃虫在转基因棉中后期主茎顶部嫩叶、侧枝嫩芽及嫩叶、蕾、铃上完成幼虫和蛹期的发育时间,分别比敏感品系棉铃虫在常规棉上的发育时间长13.4,10.7及7.0d,比敏感品系在玉米上完成发育时间长13.2～20.6d;且取食转Bt基因棉的高抗棉铃虫幼虫死亡率和活动频率高,蛹重减轻,化蛹率和羽化率降低。     

德国黑白花奶牛体型结构及其与产奶量的关系

本文通过15项体尺和10项体尺指数系统地描述了德国黑白花第一胎泌乳牛的体型结构,并研究了体型结构和产奶量之关系。结果显示,在所有体尺中仅臀角宽和产奶量的相关(0.3681)达到显著水平,其它体尺的相关均较小;胸深和腰角宽对产奶量的通径系数分别为0.3209和0.3214,多数体尺对产奶量的直接影响均较小。德国黑白花奶牛体型结构存在尻长等于十字宽和胸深是胸宽两倍的特点。     

李品种生化分类的初探——几种李果实中糖类物质的气相色谱分析

本实验采用气相色谱法,测定了李果实中不同糖类物质含量。从测定结果中发现,熊岳的美丽李的蔗糖含量是大李子蔗糖含量的29倍;前所的美丽李蔗糖含量和山梨醇含量均比大李子高两倍多。采样地点不同,测定结果有相同的趋势。美丽李果糖含量比大李子果糖含量多3％～5％。寺田李与美丽李、大李子之间也存在明显区别,寺田李的山梨醇含量比美丽李、大李子的山梨醇含量高3倍左右。初步认为,气相色谱法可以做为果树生化分类方法的依据之一。     

用发酵剂改良风干香肠及其理化特性的研究

为了改良风干肠的品质,试验把发酵剂人工接种入风干肠中,并且以自然发酵肠和直接烘烤的干肠作对照,通过对发酵和烘烤过程中理化指标的研究,以及对产品的感官评定来鉴定其品质。结果表明,人工接种发酵剂的风干肠有浓郁的发酵香味,酸度适中,口感颇佳;半成品水分含量在31％～32％,水分活度在0.79～0.81之间,属于中等水分肉制品;pH值在发酵过程中逐渐下降,烘烤后开始上升,半成品pH值在5.2～5.4之间;TBA值在发酵和烘烤过程中虽然一直上升,但是成品没有脂肪氧化味;在发酵和烘烤过程中色素转化率先逐渐上升而后又下降,半成品值为38％～53％,颜色较好。结果还表明,试验所采用的工艺参数可行,但最佳的工艺参数还需要进一步研究。