Factors regulating baculovirus late and very late gene expression in transient-expression assays.

Eighteen genes of Autographa californica nuclear polyhedrosis virus are necessary and sufficient to transactivate expression from the late vp39 promoter in transient-expression assays in SF-21 cells. These 18 genes, known as late expression factor genes (lefs), are also required to transactivate the very late promoter of the polyhedrin gene, polh, but expression from this promoter is relatively weak compared with expression from the vp39 promoter. To further define the factors required for late and very late promoter expression, we first determined that the eighteen lefs were also required for expression from two other major baculovirus promoters: the late basic 6.9-kDa protein gene, p6.9, and the very late 10-kDa protein gene, p10. We next examined the effect of the very late expression factor 1 gene (vlf-1), a gene previously identified by analysis of a temperature-sensitive mutant, in the transient expression assay and found that vlf-1 specifically transactivated the two very late promoters but not the two late promoters. We then surveyed the Autographa californica nuclear polyhedrosis virus genome for additional genes which might specifically regulate very late gene expression; no additional vlf genes were detected, suggesting that VLF-1 is the primary regulator of very late gene expression. Finally, we found that the relative contribution of the antiapoptosis gene p35, which behaves as a lef in these transient-expression assays, depended on the nature of the other viral genes provided in the cotransfection mixtures, suggesting that other viral genes also contribute to the ability of the virus to block apoptosis.     

白背飞虱种群动态关联分析及预测模型的研究

根据灰色系统关联分析的基本原理,提出了白背飞虱种群动态的加权关联度预测法。衢县早稻后期白背飞虱发生量与历年6月25～30日平均百丛虫量X_1（t）、同期若虫比例X_2（t）、迟熟品种比例X_3（t）、6月下旬水分积分指数X_4（t）和平均气温X_5（t）等因素的关联序为：X_2（t）＞X_1（t）＞X_3（t）＞X_5（t）＞X_4（t）。据此建立的加权关联度预测模型,经12年资料回测和试报验证,结果令人满意。     

Characterization of a calcium/calmodulin-dependent protein kinase homolog from maize roots showing light-regulated gravitropism

Roots of many species respond to gravity (gravitropism) and grow downward only if illuminated. This light-regulated root gravitropism is phytochrome-dependent, mediated by calcium, and inhibited by KN-93, a specific inhibitor of calcium/calmodulin-dependent protein kinase II (CaMK II). A cDNA encoding MCK1, a maize homolog of mammalian CaMK, has been isolated from roots of maize (Zea mays L.). The MCK1 gene is expressed in root tips, the site of perception for both light and gravity. Using the [³⁵S]CaM gel-overlay assay we showed that calmodulin-binding activity of the MCK1 is abolished by 50 M KN-93, but binding is not affected by 5 M KN-93, paralleling physiological findings that light-regulated root gravitropism is inhibited by 50 M KN-93, but not by 5 M KN-93. KN-93 inhibits light-regulated gravitropism by interrupting transduction of the light signal, not light perception, suggesting that MCK1 may play a role in transducing light. This is the first report suggesting a physiological function for a CaMK homolog in light signal transduction.Abbreviations CaM calmodulin - CaMK (II) Ca²⁺/calmodulin-dependent protein kinase (II) - CBP CaM-binding protein - CDPK Ca²⁺-dependent protein kinase - MCK1 maize homolog of mamalian CaMK This work is supported by the National Aeronautics and Space Administration grant No: NAGW 238.     

RFLP mapping of QTLs for yield and related characters in rice (Oryza sativa L.)

Quantitative triat loci (QTLs) for yield and related traits in rice were mapped based on RFLP maps from two indica/indica F₂ populations, Tesanai 2/CB and Waiyin 2/CB. In Tesanai 2/CB, 14 intervals carrying QTLs for eight traits were detected, including 3 for grain weight per plant (GWT), 2 for number of panicles per plant (NP), 2 for number of grains per panicle (NG), 1 for total number of spikelets per panicle (TNS), 1 for spikelet fertility (SF), 3 for 1000-grain weight (TGWT), 1 for spikelet density (SD), and 1 for number of first branches per main panicle. The 3 QTLs for GWT were located on chromosomes 1, 2, and 4, with 1 in each chromosome. The additive effect of the single locus ranged from 2.0 g to 9.1 g. A major gene (np4) for NP was detected on chromosome 4 within the interval of RG143–RG214, about 4cM for RG143, and this locus explained 26.1% of the observed phenotypic variance for NP. The paternal allele of this locus was responsible for reduced panicles per plant (3 panicles per plant). In another population, Waiyin 2/CB, 12 intervals containing QTLs for six of the above-mentioned traits were detected, including 3 for GWT, 2 for each of NP, TNS, TGWT and SD, 1 for SF. Three QTLs for GWT were located on chromosome 1, 4, and 5, respectively. The additive effect of the single locus for GWT ranged from 6.7 g to 8.8 g, while the dominance effect was 1.7–11.5 g. QTL mapping in two populations with a common male parent is compared and discussed.     

钙离子和蛋白激酶C对大鼠缺血海马脑片谷氨酸堆积的影响

采用大鼠海马脑片体外缺血模型观察钙离子和蛋白激酶Ｃ（ＰＫＣ）对神经元胞外谷氨酸（ＧＬＵ）堆积的影响,结果显示：海马脑片在体外“缺血”１０ｍｉｎ,ＧＬＵ在胞外的浓度增加４倍（从３２±４升高到１１３±１０ｐｍｏｌ／（ｍｉｎ．ｍｇＰｒ）．ｎ＝６）．Ｎ型钙通道拮抗剂蝙蝠葛苏林碱（ＤＳＬ）或无钙培养液均能有效抑制这种浓度的升高（Ｐ＜０．０１）．提示缺血１０ｍｉｎ引发的ＧＬＵ浓度升高是受Ｃａ２＋内流调控的．当脑片在缺血状况下孵育３０ｍｉｎ,ＤＳＬ只部分抑制这种ＧＬＵ堆积,而无钙培养液则无影响,但这额外的ＧＬＵ堆积可被ＰＫＣ抑制剂Ｈ－７完全阻断,而被ＰＫＣ激动剂ＰＤＢ所加强;且不受钙调蛋白抑制剂Ｃａｌｍｄａｚｏｌｉｕｍ和８－溴－ｃＡＭＰ影响．提示缺血３０ｍｉｎ,胞外ＧＬＵ的堆积受钙内流和ＰＫＣ双重调控。     

Determination of the kinetic parameters in continuous cultivation byDebaryomyces hansenii grown on D-xylose

Summary The kinetic parameters of the yeastDebaryomyces hansenii grown in continous cultivation on D-xylose were determined by different methods. While the values obtained for μ_m by the steady state and the washout methods only gave a 3% difference, the determined K_s values by the steady state and the maximal biomass output methods led a to a 305% difference. The latter method was suggested to overestimate the K_s value.     

油梨果实的生长和内含物变化的观察

本文报道对油梨果实的生长及内含物的变化的观察结果．果实生长发育过程中,以６—７份生长最快,干物质及脂肪含量由低到高变化,以１１月份增加最快,蛋白质含量由高到低递诚．１１月份后含量相对稳定,总糖和维生素Ｃ含量随果实的发育程度而下降。     

质体醌重组的D1／D2／Cytb559复合物的荧光衰减动力学和光破坏作用

光系统Ⅱ反应中心Ｄ１／Ｄ２／Ｃｙｔｂ５５９ 在分离纯化过程中失去了电子受体ＱＡ 和ＱＢ,人工合成的质体醌可以与Ｄ１／Ｄ２／Ｃｙｔｂ５５９ 复合物发生重组。癸基质体醌（ＤＰＱ）与Ｄ１／Ｄ２／Ｃｙｔｂ５９９ 复合物的重组导致该复合物的荧光强度下降及发射光谱蓝移,同时两个与光化学活性相关的长寿命（２４ ｎｓ和７３ ｎｓ）荧光衰减组分占整个荧光的百分数下降,这些结果表明ＤＰＱ作为Ｐｈｅｏ－ 的电子受体,限制了Ｐ６８０＋ ·Ｐｈｅｏ－ 的电荷重组。ＤＰＱ 的加入对Ｄ１／Ｄ２／Ｃｙｔｂ５５９复合物中Ｃｈｌａ 分子的光破坏敏感性影响不大,但β－胡萝卜素在加入ＤＰＱ 之后可以被光照破坏,这个过程可能与β－胡萝卜素的生理功能相关。     

人骨骼肌α辅肌动蛋白（α－actinin）的提取及其抗血清的制备和鉴定

本文提取人骨骼肌α辅肌动蛋白（α－ａｃｔｉｎｉｎ）是综合了文献报导有关提取兔肌α－ａｃｔｉｎｉｎ的和提取鸡胗α－ａｃｔｉｎｉｎ的方法,稍加修改而确定的。用Ｈａｓｓｅｌｂａｃｈ－Ｓｃｈｎｅｉｄｅｒ缓冲液提取骨骼肌中的肌球蛋白后,将残余物经硼酸－缓冲液提取、匀浆及高速离心去掉肌动蛋白和肌原纤维的其它成份,上清加硫酸铵至３０％,３５％饱合度所得的沉淀用２２０ｍｍｏｌ／ＬＴｒｉｓ－乙酸溶解、透析、离心后经ＤＥ－５２柱层析可得电泳纯。α－ａｃｔｉｎｉｎ。将人骨骼肌α－ａｃｔｉｎｉｎ纯化制品免疫了三只大耳白纯种家兔,两个多月后,三只兔子都产生免抗人骨骼肌α－ａｃｔｉｎｉｎ的特异抗血清,用双向免疫扩散法和酶联免疫吸附试验（ＥＬＩＳＡ）测定,产生的抗体效价较高,用双扩散法测定效价为１：３２,用ＥＬＩＳＡ测定,用比率法判断结果,效价最高者为１：１００,０００左右,经免疫电镜观察结果证实,上述抗血清可以满足进一步实验要求。     

Glycosphingolipid acyl chain orientational order in unsaturated phosphatidylcholine bilayers.

The glycosphingolipid, galactosyl ceramide (GalCer), was studied by 2H nuclear magnetic resonance (NMR) in fluid phospholipid bilayer membranes, with regard to arrangement of its acyl chain. For this purpose, species with perdeuterated 18-carbon fatty acid (18:0[d35]GalCer) or with perdeuterated 24-carbon fatty acid (24:0[d47] GalCer) were dispersed in bilayers of the 18-carbon phospholipid, 1-stearoyl-2-oleoyl-phosphatidylcholine (SOPC). For 18:0[d35] GalCer, smoothed profiles of the order parameter, SCD, were found to be very similar to one another over the range of glycolipid concentration, 5-40 mol%. In addition, they were very similar to orientational order parameter profiles well known from the literature on phospholipid and glycolipid acyl chains (which deals in general with membranes of homogeneous chain length in the range 14-18 carbons). Corresponding order parameter profiles for the long-chain species, 24:0[d47] GalCer, were also similar to one another for glycolipid concentrations between 5 and 40 mol%. Their shapes, however, were distinctly different from those of the shorter chain analogues. SCD profiles for the two species were quantitatively similar to a membrane depth of C15. SCD values at C16 and C17 were approximately 20 and 30%, respectively, higher for the long-chain glycosphingolipid than for its short-chain analogue in SOPC. Nitroxide spin labels attached rigidly to C16 of the long-chain glycolipid in SOPC gave electron paramagnetic resonance (EPR) order parameters that were twice as high as for a spin label at C16 on the shorter chain glycolipid. Comparison was made between spectra of 24:0[d47] GalCer in SOPC and fully hydrated bilayers of the pure 24:0[d47] GalCer, a system that is considered to be partially interdigitated in fluid and gel phases. The resultant 2H NMR order parameter profiles displayed similar features, indicating that related organizational properties exist in these fluid systems. Effective chain length of 24:0[d47] GalCer within the SOPC membrane was calculated using the method of Schindler and Seelig (1975. Biochemistry, 14:2283-2287). The result suggested that the long-chain fatty acid should protrude roughly one third of the host matrix chain length across the bilayer midplane. However, a treatment of the same order parameters making very few assumptions about chain conformation indicated a high degree of orientational flexibility for the "extra" length of the long chain fatty acid.(ABSTRACT TRUNCATED AT 400 WORDS)