接触二氧化硫后小麦叶片中逆境乙烯的生物合成

AVG和AOA强烈抑制二氧化硫处理小麦叶片中乙烯产生和ACC合成,对MACC的形成也有一定的抑制作用。CoGl_2明显抑制乙烯产生,而ACC大量积累,MACC含量则未因ACC增加而相应增加。DNP和CCCP也抑制乙烯产生,但前者引起ACC大量积累,后者引起ACC含量下降。CHI对乙烯产生和ACC形成均显示强烈的抑制作用,同时也明显抑制MACC形成。这表明小麦叶片接触SO_2引起的逆境乙烯也是循蛋氨酸→SAM→ACC→乙烯途径。     

Ti质粒T区tms基因的分离及其对高等植物分化的影响

根癌农杆菌Ti质粒的T区DNA带有致瘤基因,其基因1和基因2编码生长素吲哚乙酸生物合成途径中的两个酶。以pGV 354(pBR322质粒中插有Ti质粒C 58 T区DNA的HindⅢ15—HindⅢ22大片段)重组质粒出发,我们分离了基因1和基因2,并构建了带有卡那霉素抗性基因的重组质粒pBZ 692,通过基因载体pGV 3850,我们将基因1和基因2引入了高等植物。结果证明基因1和基因2能促使烟草、向日葵、土豆等转化组织分化长根,转化的根在MS_0培养基上能脱分化形成愈伤组织并自主生长,在转化的组织中有转化标记胭脂碱的存在。     

Characterization and Location of Met5-Enkephalin-Arg6-Phe7 Stored in Various Rat Brain Regions

A specific antiserum against met⁵-enkepha-lin-arg⁶-phe⁷ was raised and used to study the distribution and characterization of met⁵-enkephalin-arg⁶-phe⁷-like immunoreactive material in rat brains by radioimmunoassay and immunohistochemical procedures. The antiserum appears to be directed to the COOH-terminus of the peptide, as it fails to cross-react with met⁵-enkeph-alin, met³-enkephalin-arg⁶, met⁵-enkephalin-arg⁶-arg⁷, met⁶-enkephalin-lys⁶, and leu-enkephalin. However, it cross-reacts with phe-met-arg-phe by about 10% and with phe-met-arg-phe-NH₂ to an insignificant degree. The highest content of met⁵-enkephalin-arg⁶-phe⁷ was found in the striatum, which contains a dense network of immunoreactive varicose fibers and terminals, as well as immunoreac tive cell bodies. The met⁵-enkephalin-arg⁶-phe⁷ in striatum can be released in a Ca²⁺-dependent manner by a depolarizing concentration of KC1, raising the possibility of a neu-roregulatory role for met⁵-enkephalin-arg⁶-phe⁷. Characterization of the immunoreactive material by gel filtration and high pressure liquid chromatography revealed the presence of multiple forms of immunoreactive material in some brain regions.     

Serum Albumin Washing Specifically Enhances Arachidonate Incorporation into Synaptosomal Phosphatidylinositols

Arachidonate incorporation into synaptosomal phospholipids was shown to be affected by factors including the procedure for preparation of the membrane fractions and preincubation of synaptosomes prior to assay of incorporation of arachidonate into both phosphatidylcholine (PC) and phosphatidylinositol (PI). However, the inhibition toward incorporation into PIs, but not PCs, was fully reversed when the membranes were washed with bovine serum albumin. A twofold increase in arachidonate incorporation into PIs was also observed when freshly prepared synaptosomes were washed with serum albumin immediately before assay of incorporation activity. The inhibitory action is thought to be due to an increase in polyunsaturated fatty acids and/or their oxidation products which may then elicit a special effect on the acyltransferase responsible for transferring arachidonate into phosphatidylinositols. The differences in fatty acid uptake and response to serum albumin also suggest the presence of different acyltransferase for acyl transfer to PIs and PCs.     

Resonance Raman scattering and optical absorption of adrenodoxin and selena-adrenodoxin

Raman spectra have been recorded for native and selenium substituted adrenodoxin in dilute solution. Adrenodoxin shows three bands at 397, 350 and 297 cm^?1, all polarized, which can be associated with the iron-sulfur core. Selenium substitution leaves the 350 cm^?1 band essentially unshifted, but the other two bands disappear and are replaced by new bands at 355 and 263 cm^?1. The 350 cm^?1 band is assigned to stretching of iron-sulfur (cysteine) bonds, while the 397 and 297 cm^?1 bands are associated with vibrations of the labile sulfur atoms. The iron-selenium charge transfer bands were observed at 438 and 480 nm for the oxidized form and at 580 nm for the reduced form. The reduced selena-adrenodoxin displayed absorption maxima at 4, 450 and 5, 550 cm^?1, which can be assigned to the d-d transitions of high-spin ferrous ion. From this data and the reported g-values of electron paramagnetic resonance signals, the spin-orbit coupling constants were calculated to be 170 and 210 cm^?1 for the respective d-d transitions.     

Factors affecting pathogenicity of NPV preparations to the corn earworm,Heliothis armigera

Pathogenicity ofHeliothis nuclear polyhedrosis virus (HSNPV) to the corn earworm,Heliothis armigera, was studied using 3 different inoculative methods. The LD50 values of 4^th-instar larvae inoculated with corn-fed, diet-fed and inoculum-imbiding method were 1.85×10⁶, 2.55×10⁵ and 1,22×10³ PIBs/larva, respectively. The inoculum-imbiding is more sensitive and convenient for inoculatingH. armigera with HSNPV. The HSNPV product, Elcar^®, was highly pathogenic toH. armigera, the LD50 values of 2^nd-, 3^rd- and 4^th-instar larvae being 27, 83 and 1,221 PIBs/larva, respectively, as measured by the inoculum-imbiding method. The mortality of 4^th-instar larvae caused by HSNPV was increased, but the incubation period was shortened with higher incubation temperatures. However, the high temperature at 35°C caused a lower mortality, and a prolongation of the median lethal time (LT50). Stability and persistence of HSNPV preparations were better in January–February and April–May than in June–July and October–November periods when sprayed on corn silks under field conditions. The HSNPV was inactivated by weak alkaline dew (pH 8.1) collected from soybean leaves, but it remained active on those from corn, tomato and asparagus with pH 7.2–7.3. The artificial heavy rainfall of 242 mm/h for 30 min did not wash off HSNPV preparations sprayed on the corn silks.     

云南10个民族红细胞酸性磷酸酶型分布调查

用淀粉凝胶电泳法对云南省汉族及9个少数民族的红细胞酸性磷酸酶(ACP_1)的表型分布进行了调查,检出A、BA和B3种表型,计算得云南汉、彝、白、傣、瑶、佤、哈尼、布朗、基诺和拉祜族ACP_1~A、ACP_1~B的基因频率依次为0.2067、0.7933;0.2406、0.7594;0.2341、0.7659;0.3750、0.6250;0.2300、0.7700;0.2727、0.7273;0.3594、0.6406;0.3036、0.6964;0.2381、0.76119和0.4474、0.5526。未发现ACP_1~C基因及其它稀有基因。研究表明,ACP_1表型的分布存在着一定的种族与民族差异。