Removal of swine zonae pellucidae with sequential exposures to pronase and acidified medium

Exposure to acidified PBS (pH 3) for 60 sec removed swine zonae pellucidae from 70.4% of 27 swine morulae, and 73.7% of these formed blastocysts in culture. Further investigations revealed that treating embryos with 0.5% pronase and acidified PBS (pH 3) for 30 sec each was more effective. Zonae were removed in 90.6% of 85 embryos (four-cell to morulae) treated. A total of 76.9% of 65 zona-free embryos and 81.6% of 38 untreated embryos formed blastocysts (P > 0.05). An additional 57 untreated and 49 zona-free embryos (morulae to blastocysts) were transferred to seven recipient sows. Four sows returned to estrus (18 to 27 days), but three others were pregnant when slaughtered at 38 to 42 days. One pregnant sow had received a combination of five zona-free and six untreated embryos and demonstrated the potential for further development of treated embryos in vivo.     

Post-thawing survival of motile ram sperm after isolation by layering on protein columns

Post-thawing survival of ram sperm was examined after semen which had been layered on top of isolation columns containing solutions of bovine serum albumin (BSA) in Tris diluent was processed for freezing by the pellet method. Sperm isolated from the bottom of the BSA column had better post-thawing survival than sperm from the top of the column. The efficiency of sperm isolation was affected by the concentration of BSA in the column, the holding time of semen on the column and the concentration of sperm in the layered semen. The best post-thawing survival of sperm occurred when semen diluted to a concentration of 200 x 10(6) sperm/ml was layered on a column of 6% BSA in Tris diluent and the bottom layer of the column was isolated for freezing after two hours' holding time.     

海南岛玉米上的多堆柄锈菌

<正> 在采集植物病害标本的过程中,我们曾于1972年12月中旬在海南岛乐东县尖峰地区“金-03”号玉米自交系的植株上采得一种锈菌——多堆柄锈菌(Puccinia polysora Underw.)。其后,1974年和1979年在该岛的陵水及崖县等地亦分别采到过此菌。据 Weber(1973)和 Kranz(1978)等报道,P.polysora广泛地发生于世界热带地区的玉米上;在我国,戴芳澜等(1937)、天云章(1949)、谌多仁(1963)以及戚佩坤(1978)等所报道的国内玉米上的锈菌均属于高粱柄锈菌 P.sorghi。作者在海南岛玉米上采得的这种锈菌(P.polysora),国内尚无报道。     

Genetic Regulation of Flowering in Grafts on Pisum sativum L

Lf, E, Sn, and Hr are major loci that condition the flowering and photoperiod responses of Pisum sativum L. Genetic lines containing the dominant alleles of these loci are characterized by flowering in long days, but having a prolonged (>50 node) vegetative phase in short days. A representative of this class, response type G, was used as a receptor in short days for donors of other flowering response types. The qualitative and quantitative flowering response of G receptors depended on the genotype of the donor. Donors containing sn hr induced the earliest development, followed by sn Hr and Sn hr donors. The Lf and E loci in foliar donors apparently did not affect flowering of G. Five-leaved > single-leaved > cotyledonary donors in effecting a flowering response in G, in part due to the longer life of the foliar donors. The responses of G to the various donors were generally consistent with the proposed roles of Lf, E, and Sn, but the role of Hr in these grafts was unclear.     

Effects of Boron Deficiency on Rubidium Uptake and Photosynthesis in the Diatom Cylindrotheca fusiformis

Culturing the diatom Cylindrotheca fusiformis under boron-deficient conditions leads to changes in ⁸⁶Rb uptake and photosynthesis prior to any effect on the rate of cell division. The influx rate of ⁸⁶Rb into boron-deficient cells was 79% of the control rate after 5 to 5.5 hours culture. Despite lowered ⁸⁶Rb influx, however, boron-deficient diatoms accumulated more ⁸⁶Rb than did control cells; this was due to the deficient cells' lower efflux rate. After 24 hours culture, boron-deficient cells had accumulated 30% more ⁸⁶Rb than had control cells, while releasing ⁸⁶Rb at only one-half the control rate. Increased photosynthetic rates were another effect of boron deficiency during this early stage of culture. Prior to 20 hours boron-deficient culture, diatoms had photosynthetic rates 37% greater than those of control cells. Corresponding to the increase in photosynthesis, boron-deficient diatoms had 12% more carbohydrate than control cells after 16 hours culture.     

蛋白酶抑制剂的研究——1.蛋白酶抑制剂产生菌的筛选

酶抑制剂,是指能使酶蛋白中的活性基团或活性中心的化学性质发生改变,从而引起酶活性下降或完全丧失的物质。而蛋白酶抑制剂除能消炎,抗消化性溃疡外,还能用来预防癌症,识别细胞或组织中的各种蛋白酶,用它做亲     

Growth and epinasty of marigold plants maintained from emergence on horizontal clinostats

Dry weight, leaf number, and leaf size of marigold plants (Tagetes patula) grown from emergence for 18 days on horizontal clinostats rotating at 15 revolutions per hour (rph), were similar to those of plants grown for the same period on vertically oriented clinostats rotating at 15 rph. The horizontally grown plants exhibited some epinasty which disappeared when plants were placed upright for 24 hours. Vertically grown plants when placed on horizontal clinostats for 24 hours exhibited more epinasty than plants grown from emergence on horizontal clinostats.

Data are provided to demonstrate that leaves undergo movement (bending) during each rotation cycle that leads to the development of a leaf curvature that is oriented away from the direction of rotation. The results of this study suggest that epinasty of plants placed on horizontal clinostats could be due to uncontrolled movement of plants during rotation rather than controlled by gravity nullification. The usefulness of horizontal clinostats for gravity nullification or simulating weightlessness on plants is questioned.

     

Enzymes of Krebs-Henseleit Cycle in Vitis vinifera L: III. In Vivo and In Vitro Studies of Arginase

Ornithine carbamoyltransferase (OCT) activity was detected in extracts from mature leaves, fruit, germinating seeds, and seedlings of Vitis vinifera L. Michaelis-Menten constants for OCT were 3.5 millimolar for carbamyl phosphate and 5.5 millimolar for l-ornithine. Concentrations of l-ornithine greater than 10 millimolar slightly inhibited the enzyme, whereas carbamyl phosphate at concentrations greater than the optimal (about 10 millimolar) did not affect OCT activity. l-Citrulline formation was linear with incubation period for the first 25 minutes and with increasing amounts of enzyme up to an equivalent of about 200 milligrams of fresh tissue. The optimum pH for in vitro OCT activity was between 8.4 and 8.8, and the optimum incubation temperature was 38 C.     

麻疯树毒素的分离及其某些性质

用磷酸盐缓冲液萃取,硫酸铵盐析及葡聚糖凝胶G-100柱层析后,从麻疯树种子分离出三个蛋白组分。其表观分子量分别约为34000、27000和9500道尔顿;等电点分别为8.1、8.8和8.8.它们在紫外区呈现典型的蛋白吸收光谱。组分Ⅰ毒性最大,小鼠腹腔注射半致死量(LD₅₀)为6.39mg。