小麦—天兰偃麦草—黑麦三属杂种花粉植株诱导条件的研究

研究表明,三属杂种处于单核中晚期阶段的花粉最适于诱导形成愈伤组织。低温预处理对促进三属杂种花粉愈伤组织的诱导有一定的作用。利用以马铃薯提取物为基础物质的马铃薯-Ⅱ培养基作诱导培养基,其愈伤组织诱导与分化的频率比目前两个较好的合成培养基要高。同一个三属杂种F_1春、秋播种植株之间在形成愈伤组织的能力上有较大的差异,秋播材料形成愈伤组织的能力明显高于春播材料。F_(?)杂种植株诱导愈伤组织和分化植株的频率均比F_1杂种明显提高。     

Metabolism of l-threonine and fatty acids and tylosin biosynthesis in Streptomyces fradiae

Abstract In Streptomyces fradiae l -threonine is catabolized by threonine dehydratase or threonine aldolase to 2-ketobutyrate or acetaldehyde and glycine, respectively. Threonine dehydratase synthesis is repressed and its activity is inhibited by NH₄⁺ ions. Threonine aldolase is not repressed by NH₄⁺ ions and its activity is slightly stimulated by these ions. The addition of threonine to the medium increased pronouncedly the fraction of non-branched fatty acids with an even carbon number under conditions when threonine dehydratase was repressed and inhibited. The results indicate that threonine serves as a source of propionyl-CoA and 2-methylbutyryl-CoA and also of acetyl-CoA required for tylosin and fatty acid biosynthesis.     

木耳属种间杂交技术研究 Ⅰ.木耳菌丝原生质体的形成与再生

本文比较了不同酶液、渗透压稳定剂、酶解温室及菌丝培养基成份等因素对木耳属(Auricularia)中木耳(Auricularia auricula)和毛木耳(Auricularia polytricha)菌丝释放原生质体的作用及影响。用0.5%纤维素酶加0.5%蜗牛酶的混合酶液,以0.6M的MgSO_4为稳定剂,在34℃下可自两种菌丝体获得大量原生质体。对原生质体再生条件的研究表明,纤维二糖和菌丝体培养物浸提物对再生有明显促进作用,再生率达20%左右。本文还用VBL型荧光增白剂观察了菌丝脱壁以及原生质体细胞壁再生的过程。     

诱导小麦-天兰偃麦草-黑麦三属杂种花粉植株的研究

以法国六倍体小黑麦为母本,分别与普通小麦(Triticum aestivum)和天兰偃麦草(Elytrigia intermedia of Agropyron glaucum)的杂交后代中的中间类型3号和5号杂交。由此获得的三属杂种F_1性状介于亲本之间,兼有三属亲本类型的特征,呈中间类型。用马铃薯-Ⅱ培养基培养三属杂种F_1的花药,诱导花粉愈伤组织。将所获得的愈伤组织转入190-2培养基进行分化,已成功地诱导出一批三属间杂种花粉植株,并用Giemsa显带技术鉴定花粉植株的染色体组组成。     

白魔芋和花魔芋葡甘露聚糖研究

从白魔芋和花魔芋的块茎中分离纯化出两种魔芋葡甘露聚糖(Konjac Glucomannan,简称KGM),分别名为白魔芋葡甘露聚糖(aKGM)和花魔芋葡甘露聚糖(rKGM)。通过超离心、玻璃纤维纸电泳和凝胶过沪证明aKGM和rKGM都是均一的多糖。这两种多糖都由甘露糖(M)和葡萄糖(G)组成,其克分子比G/M:aKGM为1:1.69,rKGM为1:1.60,分子量前者为8.09×10~5,后者为7.37×10~5。酶水解实验和红外光谱分析说明aKGM和rKGM都是由甘露糖和葡萄糖以β-1,4-糖苷键连接的杂多糖;有O-乙酰基的特征吸收峰,说明在某些糖残基上可能有乙酰基团。     

Effect of inorganic phosphate on the secretion of pectinolytic enzymes by Aspergillus niger

Inorganic phosphates, taken as NaH₂PO₄ or KH₂PO₄, stimulated the production of pectinolytic enzymes and enhanced by up to two-fold the growth of Aspergillus niger in submerged liquid culture of apple pomace. Production of extracellular enzymes of endo- and exo- types, showed a different response to concentrations of phosphate in the medium.     

Gene amplification at a locus encoding a putative Na+/H+ antiporter confers sodium and lithium tolerance in fission yeast.

We have identified a new locus, sodium 2 (sod2) based on selection for increased LiCl tolerance in fission yeast, Schizosaccharomyces pombe. Tolerant strains have enhanced pH-dependent Na+ export capacity and sodium transport experiments suggest that the gene encodes an Na+/H+ antiport. The predicted sod2 gene product can be placed in the broad class of transporters which possess 12 hydrophobic transmembrane domains. The protein shows some sequence similarity to the human and bacterial Na+/H+ antiporters. Overexpression of sod2 increased Na+ export capacity and conferred sodium tolerance. Osmotolerance was not affected and sod2 cells were unaffected for growth in K+. In a sod2 disruption strain cells were incapable of exporting sodium. They were hypersensitive to Na+ or Li+ and could not grow under conditions that approximate pH7. The sod2 gene amplification could be selected stepwise and the degree of such amplification correlated with the level of Na+ or Li+ tolerance.     

Phosphorylation of atrial natriuretic factor R1 receptor by serine/threonine protein kinases: evidences for receptor regulation

The 130 kDa atrial natriuretic factor receptor (ANF-R₁) purified from bovine adrenal zona glomerulosa is phosphorylated in vitro by serine/threonine protein kinases such as cAMP-, cGMP-dependent and protein kinase C. This phosphorylation is independent of the presence of ANF (99–126) and there is no detectable intrinsic kinase activity associated with the ANF-R₁ receptor or with its activated form. In bovine adrenal zona glomerulosa cells, TPA (phorbol ester) induces a marked inhibition of the ANF-stimulated cGMP accumulation as well as of the membrane ANF-sensitive guanylate cyclase catalytic activity without any change in the binding capacity or affinity for ¹²⁵I-ANF. However, we have demonstrated a significant ³²P incorporation in the ANF-R₁ receptor of the TPA-treated cells. The effect of TPA on the zona glomerulosa ANF-R₁ receptors was abolished by calphostin C, a specific protein kinase C inhibitor. Altered ANF actions due to blunted response of guanylate cyclase to ANF could be a consequence of the ANF receptor phosphorylation by excessive activity of protein kinase C and might be involved in the pathogenesis of hypertension.Abbreviations ANF Atrial Natriuretic Factor - ANF-R₁ Atrial Natriuretic Factor Receptor, subtype 1 - ATP Adenosine Triphosphate - CaCl₂ Calcium Chloride - cAMP Adenosine cyclic 3,5-Monophosphate acid - cGMP Guanosine cyclic 35-Monophosphate acid - EDC 1-Ethyl-3-[3-Dimethylaminopropyl] Carbodiimide - EDTA Ethylenediaminetetraacetic Acid - GTP Guanosine Triphosphate - IBMX 3-isobutyl-1-methylxanthine - kDa Kilodaltons - MgCl₂ Magnesium Chloride - MgAC Magnesium Acetate - NaCl Sodium Chloride - PAGE Polyacrylamide Gel Electrophoresis - PKA cAMP-dependent protein kinase - PKG cGMP-dependent Protein Kinase - PKC Calcium/Phospholipid-dependent Protein Kinase - RIA Radioimmunoassay - SDS Sodium Dodecyl Sulfate - SHR Spontaneously Hypertensive Rat - Tris HCl Tris (Hydroxymethyl) aminomethane Hydrochloride - TPA 12-O-Tetradecanoyl-Phorbol-13-Acetate     

取食雄蜂蛹粉对龟纹瓢虫和异色瓢虫卵黄发生的影响

本文比较了龟纹瓢虫Proylea japonica和异色瓢虫Harmonia axyridis取食蚜虫和取食雄蜂蛹粉时的卵黄发生情况.当取食雄蜂蛹粉时,体内卵黄蛋白出现迟,积累速度慢,产卵前期长.但用保幼激素类似物ZR512点滴处理后则能达到与食蚜对照相当的水平.ZR512对取食雄蜂蛹粉瓢虫的作用显著大于取食岈虫者.进一步的研究表明,ZR512能促进这两种瓢虫取食雄蜂蛹粉,但对成虫的体重没有明显的影响.因此推论,雄蜂蛹粉基本能够满足这两种瓢虫生殖的营养需要,但对其内分泌有一定的影响,使瓢虫处于类似生殖滞育的状态.本文根据不同食物条件对卵黄蛋白发生的影响不同,建议用卵黄蛋白的量作为生理指标,以快速初步筛选和评估人工饲料.