Phosphogluco mutase — a biochemical marker for group 4 chromosomes in the Triticinae

Summary Structural genes for the isozymes of phosphogluco mutase (PGM) (EC 2.7.5.1) have been located on chromosome arms 4A, 4BL and 4DS of hexaploid wheat. These results support the homoeologies observed among these chromosome arms and also support the notion of conservation of gene synteny groups within the Triticinae.     

Survival of phage M13 with uracils on one or both DNA strands

Summary The survival of M13 DNA was studied after partial replacement of thymine by uracil in the bacteriophage. Uracils carry the same genetic information as the thymines. Nevertheless in Escherichia coli wild-type cells, uracils in DNA are replaced by thymines by excision repair initiated by uracil-DNA glycosylase (UDG). Thus inactivation of uracil-containing phage DNA is solely due to repair initiated by UDG. Incorporation of uracils was achieved in one or in both strands, either randomly or site-specifically using differently uracylated oligonucleotides. The results show that up to 580 uracils can be repaired without a significant decrease in survival if the uracils are localized in the (–) strand only. Incorporation of 246 uracils into the (+) strand leads to 30% or 10% survival when expressed in Escherichia coli strains CMK and JM103, respectively. However, when uracils are distributed over both strands a sharp decrease in survival occurs. This shows that the repair of two uracils localized in close proximity on opposite strands of the DNA by the excision repair mechanism is difficult, whereas uracils occurring in one strand are repaired more efficiently, irrespective of their number.     

Genetic linkage map of rye (Secale cereale L.)

Communicated by G. Wenzel     

小偃6号小麦旗叶直立基因的染色体定位

本文首次对小麦旗叶姿态进行了比较系统的细胞遗传学研究。单体、端体的F_1及F_2分析表明:中国春2D染色体上至少有两个旗叶下披基因,即位于2DL上的P_1和2DS上的P_2,前者表达能力很强,后者则较弱,与小偃6号旗叶直立基因共存时分别表现为显性和隐性;小偃6号的旗叶直立基因E也位于2D染色体上,同(P_1+P_2)共存时表现为隐性,仅与P_2共存时则表现为显性。文章还就这些基因的染色体操作等进行了讨论。     

Differences between genetic and physical centromere distances in the case of two genes for male sterility in barley

Summary Linkage studies with thirty translocations (one of the two chromosomes involved being number 4) in relation to msg24 (chromosome 4) and thirteen translocations (one of the two chromosomes involved being number 6) in relation to msg6 (chromosome 6) show without exception close linkage for all combinations tested. The results indicate that both genes are located genetically in or close to the centromere regions of their chromosomes.Cytological analysis of two BTT stocks (balanced tertiary trisomics) ascertained the respective chromosome arms (both msg24 and msg6 on the short arms) and revealed marked differences between genetic and physical centromere distances. The reason is obviously the high content of centromeric heterochromatin occupying both the chromosome arms involved.     

Immune expulsion of the nematode Aspiculuris tetraptera from mice given primary and challenge infections.

The distribution of larval Aspiculuris tetraptera was studied in 4-week-old male and female CFLP mice. Whereas on days 10–12 the larvae were entirely confined to the anterior third of the colon, by day 14 larvae could be found throughout the colon. After day 17 the larvae were again restricted to the anterior colon. This change in distribution was co-incident with a loss of a large proportion of the worm burden, which occurred more consistently in female than in male mice.The degree of acquired immunity stimulated by various immunizing regimens was assessed by the survival of a challenge infection in experimental and control mice. It was found that a high level of immunity was achieved by exposure to a 19-day primary infection, a 36-day low-level infection and also by three 6-day infections, in each of which the larvae were removed by piperazine treatment immediately after the crypt phase.     

江苏省县域森林生态安全评价及空间计量分析

通过考察生态区位因素对森林生态安全的影响,建立评价指标体系,研究其空间相关性的内在效应机制,从而实现森林生态安全的评价与监测。以江苏省80个区县为研究对象,基于2000—2015年面板数据,运用熵权法、专家法及模糊物元法计算森林生态安全指数,然后结合气象类指标及地形类指标计算生态区位系数,再用该系数修正森林ESI,同时结合Arc GIS技术、空间相关性分析、SLM与SEM模型得出如下结论:(1)人口密度、单位面积能源消耗量、退耕还林面积占比等指标权重最大;(2)生态区位系数高值区主要分布在江苏南部少数地区,低值区主要分布在江苏东北部;(3)苏南地区森林生态安全状况整体好于苏北及中东部地区;(4) 2000—2015年,江苏省67.5%的区县森林ESI呈现出较明显下降趋势,反映出江苏省森林生态安全发展状况不容乐观;(5)江苏省县域森林ESI整体空间相关性显著(P≤0.01),但2000—2015年空间聚集程度有所下降,且Low-Low聚类显著性更强;(6)森林ESI在江苏省县域间为扩散效应与回流效应并存。     

道路影响下野生动物廊道的选址——以大熊猫保护廊道为例

沿道路设置供野生动物迁徙、扩散和连接栖息地的廊道是应对道路干扰最有效的措施,科学选址则是野生动物廊道建设的前提,也是廊道研究的薄弱领域。以大熊猫廊道为例对野生动物廊道选址指标体系、方法和程序进行了探索,将栖息地特征、地形因素、植被可转化性、工程成本作为大熊猫廊道选址指标,基于Arcgis和栖息地格局、海拔、坡度、植被数据,为四川306省道椅子垭口段确定了两处大熊猫廊道位置,并用监测数据证明了所选位置具有较大的可行性和准确性。研究表明栖息地格局是廊道选址的重要基础,应侧重对地形因素的研究。研究为廊道选址方法和流程进行了示范,还对选址指标体系优化、提高选址的科学性进行了探讨,有助于推动野生动物廊道研究从理论探索走向实际应用。     

蛋白质亚细胞定位的识别

根据蛋白质的亚细胞定位,将蛋白质分为12类,用离散量的数学理论,以蛋白质中400个氨基酸二联体数目构成离散源,通过计算离散增量预测蛋白质的亚细胞定位,用Self-consistency和Jackknife两种方法测试均获得较高的预测成功率。结果表明：Self-consistency方法预测成功率为84．5％,Jackknife方法预测成功率为81．1％。     

达标污水离岸排海末端处置技术研究综述

达标污水离岸排海处置具有低成本、高处理率等优点,是国内外沿海港口和临港工业园区进行污水处置的重要选择。介绍了国内外达标污水离岸排海末端处置技术的发展情况,分析了排污口位置选划、扩散器射流参数及水力结构优化等研究技术上存在的问题。认为排污口位置选划应在水动力、污染物扩散、泥沙冲淤及工程经济因素分析的基础上,还需要重点考虑污水排放对区域生态要素长期的影响;排海末端扩散器射流参数及水力结构优化也尤为关键,不仅直接影响稀释扩散效果,而且涉及到主管、上升管、喷口等多个可控因子,可以采用建立物理模型、数值模型及量纲分析等方法,合理优化扩散器的结构参数和扩散器的型式,对提高达标污水离岸处置的效果具有重要意义。