枯草杆菌中性蛋白酶天然抑制剂的筛选

用透明因法和福林──酚法筛选了２１种植物中的蛋白酶活性抑制剂,其中来自鼓皮、高粱、玉米和土豆的抑制剂的活性在本研究条件下达５０％以上。进一步研究了麸皮、玉米两种抑制剂在不同温度和ｐＨ值下的稳定性,结果表明,两者的稳定性相差甚远,是两类不同的抑制剂。玉米抑制剂比麸皮抑制剂更稳定。     

两个水稻抗源与其育成新品种对褐飞虱生物学特性的影响

本试验对褐飞虱若虫生存率、发育进度、体重、种群建立以及成虫全氨基酸含量进行测定分析．结果表明,抗源品种上取食的褐0飞虱若虫存活率降低20%～40％;发育进度慢了1—2个龄期,体重轻13．2—17mg/10头,群体增长数量减少4倍以上。反映出抗源品种对褐飞虱的生存率、体重、发育进度及群体增长数量等生物学特性存在不良的影响,其育成品种也表观出相似的特点。成虫取食后全氨基酸测定结果表明,取食抗性品种后,虫体内氨基酸总含量偏低．与感虫品种相比相差2倍。     

人参寡糖素对三七悬浮培养细胞生长的效应

从人参培养细胞的细胞壁中分离纯化到不同分子量的单体人参寡糖素。试验结果表明命名为人参寡糖素Ⅶ和人参寡糖素Ⅷ的两种寡糖素对三七悬浮培养细胞的生长具有明显的促进作用,其增长率分别为１９．３４％和１０．５８％,人参寡糖素Ⅶ的适宜浓度为５—１０ｍｇ／ｌ。在高浓度下（大于２５ｍｇ／ｌ）稍抑制培养细胞生长。在细胞培养２２天（指数生长期）后．加入１０ｍｇ／ｌ的人参寡糖素Ⅶ．然后再培养２天。其生长速率即提高,加入人参寡糖素Ⅷ后．缩短了三七细胞悬浮培养生长的延缓期．提前进入对数生长期和指数生长期,并在对数生长期和指数生长期作用最明显,因而最终收获时培养细胞的产率增加。     

银杏授粉研究初报

本文报道银杏授粉的适宜品种,气候条件、不同时期、方法、浓度、雌花不同发育阶段等试验结果．为提高银杏的座果率提供有效的技术措施。     

Molecular basis for the polymorphic forms of human serum paraoxonase/arylesterase: glutamine or arginine at position 191, for the respective A or B allozymes.

The paraoxonase/arylesterase gene is located close to the cystic fibrosis gene on chromosome 7. Human serum contains two paraoxonase/arylesterase allozymes, A and B, which differ in their substrate specificities and kinetic properties. Purified A, AB, and B esterases were digested with trypsin, and the resultant peptides were compared by high-performance liquid chromatography. The elution profiles were very similar for all three samples, except for (1) one peptide (i.e., peptide A) seen only in the A and AB profiles and (2) another peptide (i.e., peptide B) seen only in the B and AB profiles. Sequencing revealed that peptide A had glutamine at amino acid position 191, whereas peptide B was generated by cleavage on the carboxy side of position 191, presumably because there was a basic (trypsin-specific) amino acid at that position. Working independently, our laboratory and one other laboratory have sequenced the coding region for paraoxonase from human liver cDNA libraries and have identified two polymorphic sites: Arg/Gln at position 191 and Leu/Met at position 54. Using PCR amplification and direct sequencing of nucleotides in both polymorphic regions with genomic DNA, we have estimated the allelic frequencies and have determined their concordance with the serum paraoxonase allozyme phenotypes in 27 unrelated adults and in 16 members of a three-generation pedigree. Among unrelated individuals, the Met/Leu polymorphism at position 54 did not correlate with the serum esterase phenotype. In contrast, the particular amino acid at position 191 correlated perfectly with serum phenotypes: A-type individuals had Gln at position 191, and B-type individuals had Arg at position 191; AB-type serum was found only with the heterozygous (Arg/Gln) combination. Pedigree analysis showed both polymorphisms to be inherited in the expected Mendelian manner and confirmed that only the 191 polymorphism showed concordance with the serum paraoxonase/arylesterase phenotypes.     

日本大萝卜引种栽培研究

本文报道日本大萝卜引种栽培的试验结果,并为推广这一蔬菜新品种提供了有效的栽培技术措施。     

乌云伞的解剖学及花粉形态学研究

八角莲属(Dysosma)是小檗科(Berberidaceae)一个重要属,全国共有7个种,大约分布于北纬23—32°,东经94—122°之间。湖北八角莲属有4个种,其中乌云伞(Dysosma lichuanensis Z. Cheng, sp. nev., ined.)为内定种,是多年生草本,它的形态特征与八角莲(Dysosma     

小兴安岭兴安落叶松泥炭藓沼泽植物的主要微量元素

小兴安岭兴安落叶松、泥炭藓沼泽是我国典型贫营养型沼泽。沼泽中树木生长发育不良,泥炭藓和常绿小灌木发育十分良好。这与沼泽水文状况和泥炭中营养元素和微量元素有关。各种植物的主要微量元素硼、铜、钴、锰、锌等含量不同,植物的不同器官中的含量亦不同,而且随季节而变化。狭叶杜香和甸杜的主要微量元素含量特点及其季节变化规律基本相似,两种泥炭藓相似,都与兴安落叶松有明显的区别。 本文重点探讨植物体内主要微量元素及其含量变化规律,为揭示贫营养型森林沼泽生态、为合理利用与改造沼泽提供依据。     

THE ROLE OF BACTERIAL SYMBIONTS IN AMINO ACID COMPOSITION OF BLACK BEAN APHIDS

To evaluate the role of bacterial symbionts (Buchnera spp.) in the black bean aphids (Aphis craccivora Koch), the aphids were treated with the antibiotic, rifampicin, to eliminate their intracellular symbiotic bacteria. Analysis of protein and amino acid concentration in 7‐day‐old of aposymbiotic aphids showed that the total protein content per mg fresh weight was significantly reduced by 29%, but free amino acid titers were increased by 17%. The ratio of the essential amino acids was in general only around 20% essential amino acids in phloem sap of broad bean, whereas it was 44% and 37% in symbiotic and aposymbiotic aphids, respectively, suggesting that the composition of the free amino acids was unbalanced. For example, the essential amino acid, threonine represented 21.6% of essential amino acids in symbiotic aphids, but it was only 16.7% in aposymbiotic aphids. Likewise, two nonessential amino acids, tyrosine and serine, represented 8.9% and 5.6% of total amino acids in symbiontic aphids, respectively, but they enhanced to 21.1% and 13.6% in aposymbiotic aphids. It seems likely that the elevated free amino acid concentration in aposymbiotic aphids was caused by the limited protein anabolism as the result of the unbalanced amino acid composition.