Two pairs of recombination signals are sufficient to cause immunoglobulin V-(D)-J joining

The minimum sequence requirements for antigen receptor V-(D)-J joining were studied by constructing recombination-substrates containing synthetic recombination signals and introducing them into a recombination-competent pre-B cell line. Two sets of heptamer (CACTGTG) and nonamer (GGTTTTTGT) sequences were shown to be sufficient to cause the V-(D)-J joining, if the 12- and 23-base pair spacer rule is satisfied. A point mutation in the heptamer sequence, or a change in the combination of the two spacer lengths, drastically reduced the recombination.     

Induction of brain D(--)-beta-hydroxybytrate dehydrogenase activity by fasting

D(m)-beta-hydroxybutyrate dehydrogenase activity is very low in normal adult rat brain; but during fasting it increases severalfold in parallel with the ketosis. The increase may represent part of a mechanism by which the brain adapts to changing patterns of substrate supply during starvation.     

氯虫苯甲酰胺干扰桃小食心虫交配的转录组分析

【目的】探明氯虫苯甲酰胺处理后桃小食心虫(Carposina sasakii)成虫的转录组差异,了解该药剂影响桃小食心虫交配的基因在功能分类和代谢通路等方面的生物学特征,挖掘与交配相关的功能基因。【方法】通过生物学实验观察氯虫苯甲酰胺干扰桃小食心虫成虫交配及繁殖情况。采用Illumina Hi SeqTM2500高通量测序技术对刚羽化的桃小食心虫雌雄成虫、羽化后4—6 h进入交配高峰期的雌雄成虫和经氯虫苯甲酰胺处理4—6 h的雌雄成虫进行转录组测序,利用Trinity软件对所得序列进行de novo组装及评估,之后对获得的有效序列进行功能注释,并利用q RT-PCR技术分析氯虫苯甲酰胺处理后相关基因的时空表达变化。【结果】氯虫苯甲酰胺处理后,桃小食心虫的交配率显著降低,寿命缩短,产卵量减少。通过合并组装桃小食心虫转录组有效序列共获得102 831条unigene,其中34 526个有注释信息。根据筛选标准,氯虫苯甲酰胺处理过程中,雌雄虫中分别有122个和147个基因发生变化,其中相同差异基因31个。对所存在的234个差异基因进行GO功能注释和富集分析结果显示,分子功能过程中的催化活性和结合活性及生物学过程中与代谢过程、单一生物体过程和细胞过程相关的5类基因占主导地位。KEGG分类结果显示,富集到代谢通路的最多,有25个,包括昆虫激素合成、药物代谢等。通过比对分析,鉴定c64662.graph_c0为桃小食心虫鱼尼丁受体基因,其长度为15 637 bp,与已报道Cs Ry R的一致性为99.0%。此外,在234个差异基因中,鉴别羧酸酯酶unigene 3个、细胞色素P450 unigene 4个、肌钙蛋白unigene3个、气味结合蛋白unigene 1个和生物钟unigene 1个。细胞色素P450 c40709.graph_c0参与昆虫激素生物合成。根据转录组中基因表达分析,12个基因在雌雄虫中的表达均出现不同变化趋势。q RT-PCR结果显示,氯虫苯甲酰胺诱导羧酸酯酶c51998.graph_c0基因上调表达;药剂处理后,雌雄虫的c57480.graph_c0和c53794.graph_c0的表达分别呈现显著的上调和下调变化,而c40709.graph_c0基因仅在雄虫中显著下调,处理6 h后c53281.graph_c0只在雌虫中上调表达;氯虫苯甲酰胺处理后3个肌钙蛋白基因在整个试验阶段均表现明显的下调趋势;雄虫中的生物钟unigene c60883.graph_c0和气味结合蛋白unigene c45675.graph_c0的变化趋势较为一致,进入暗期后立即上调,但均受氯虫苯甲酰胺的抑制。雌虫体内Ry R的表达量显著上调,而雄虫初次到达求偶高峰期前Ry R的表达量与对照差异不显著,到第2个求偶高峰期时,Ry R表达显著下调。除细胞色素P450c57480.graph_c0、c40709.graph_c0和c53281.graph_c0外,其余基因在雄虫中的表达均高于雌虫。且触角酯酶基因c54944.graph_c0、生物钟基因c60883.graph_c0和气味结合蛋白基因c45675.graph_c0在黑暗光照交替变化时,表达发生明显地上调或下调。【结论】通过转录组测序发现氯虫苯甲酰胺干扰桃小交配的作用机制是由靶标基因、嗅觉相关基因、代谢基因、生物钟基因等相互作用引起的。     

性迷向素防治桃园梨小食心虫效果初探

为了引进推广果园害虫绿色防控技术,2014年4月至7月在上海市浦东新区桃园对240mg/根梨小食心虫性信息迷向素防治梨小食心虫效果进行试验。结果表明,从花期到采收期,迷向处理园梨小食心虫成虫数量明显低于对照园。在495根/hm2和720根/hm2密度处理区,越冬代、第1代、第2代梨小食心虫雄虫迷向率均可达90%以上,种群数量减退率达78.23%~85.15%;迷向丝处理区蛀梢防效达72.73%~95.32%,蛀果防效达78.26%~95.65%,果实品质和产值高于常规对照区,经济效益显著。     

从三个平面分析汉语句式“小心(别)P”

现代汉语中有一种特殊句式——"小心P",一般情况下,"小心P"和"小心别P"语义相同,而此时的"别"是一个相对的冗余否定成分。本文主要探讨相对冗余否定句式"小心(别)P",试图从句法、语义、语用三个平面来对其进行考察,并分析这一句式所带来的歧义现象。     

木薯SCARECROW-LIKE(SCL)基因克隆、生物信息学及非生物胁迫下表达分析

[目的]克隆木薯SCARECROW-LIKE(MeSCL)基因,对其进行生物信息学分析,并检测其在非生物胁迫下的表达情况,为深入研究木薯MeSCL基因响应非生物胁迫的调控机制提供理论参考.[方法]以木薯品种D346为材料,采用RT-PCR克隆MeSCL基因编码区(CDS)序列,并利用生物信息学分析软件进行序列特征分析,采用实时荧光定量PCR检测其在干旱、盐、氧化和低温胁迫下木薯叶片中的表达情况.[结果]克隆获得的MeSCL基因编码区(CDS)序列全长1655 bp,与参考序列(GenBank登录号LOC110627921)仅存在2个碱基的差异,开放阅读框(ORF)的长度为1560 bp,编码519个氨基酸,编码蛋白分子量为57.84 kD,等电点(pI)为6.08,脂肪系数为80.46%,总平均亲水性指数为-0.195,为亲水性蛋白,含有1个信号肽、6个从内部到外部的跨膜螺旋区和5个从外部到内部的跨膜螺旋区,定位于细胞核和内质网中,属于GRAS蛋白家族成员,具有该家族的保守结构域.MeSCL蛋白三级结构模型显示,该蛋白含有14个典型的α螺旋、10个β-折叠和36个β-转角.MeSCL蛋白与橡树HbSCL蛋白的相似性最高,为90.80%,与蓖麻RcSCR、胡杨PeSCL、毛果杨PtSCR、可可树TcSCR和哥伦比亚锦葵HuSCL蛋白的相似性在80.00%左右.MeSCL基因受干旱、盐、氧化和低温胁迫诱导表达量整体呈升高趋势,但在不同处理时间的表达量存在明显差异,其中,干旱和氧化胁迫下,MeSCL基因均在处理24 h时表达量最高,分别是对照的6.05和11.17倍,而盐和低温胁迫下,MeSCL基因均在处理6 h时表达量最高,分别是对照的11.76和3.80倍.[结论]MeSCL基因参与木薯植株的非生物胁迫响应,正向调控其抗非生物胁迫能力.     

Specific inhibition of RHo(D) antibody by sialic acids

Agglutination of Rh(O)(D) erythrocytes by specific antiserum was inhibited by crude and crystalline N-acetylneuraminic acid, less inhibited by its glycoyl derivative, and weakly inhibited by its degradation product, N-acetyl-mannosamine, and by D-mannose. A brain ganglioside containing neuraminic acid and a Pseudomonas polysaccharide were even more inhibitory. Inhibition was specific for anti-D sera.     

桃园梨小食心虫性信息素迷向防治效果分析

2017年在上海市金山区采用梨小食心虫性信息素迷向散发器对露地栽培桃园和大棚栽培桃园进行了梨小食心虫迷向防治试验。结果表明,在露地栽培桃园和大棚栽培桃园内设置梨小食心虫性信息素迷向散发器能够明显干扰成虫的正常交配,使折梢率及蛀果率显著降低。露地栽培桃园中梨小食心虫迷向率为58.0%～97.2%,大棚栽培桃园为63.9%～100.0%。露地栽培桃园折梢防效为70.6%,蛀果防效为86.6%;大棚栽培桃园折梢防效为88.1%,蛀果防效为97.3%。性信息素迷向散发器对大棚栽培桃园中梨小食心虫的防治效果优于露地栽培桃园。     

超甜(糯)玉米-超级(优质)稻高产高效栽培技术

从茬口合理安排，优质高产品种筛选，播种期，育苗移栽方法，肥水调控技术以及病虫草害防治技术等方面对超甜玉米，糯玉米配套超级稻，优质稻这一高产高效种植模式进行了较为系统的研究，形成了适合于大规模生产的技术规程，在生产上大面积推广应用后，取得了十分显著的经济效益。     

利用籼粳交BIL群体定位水稻谷粒长宽比QTL

本研究以122个南粳35/N22//南粳35构建的回交重组自交系(BIL)群体为材料,通过两年重复试验,利用Win QTLcart2.5和QTLNetwork2.0软件对控制水稻谷粒长宽比的数量性状基因位点(QTL)进行定位分析。利用Win QTLcart2.5共检测到5个控制谷粒长宽比的QTLs,分别位于第1、4、5、7和12染色体上,单个QTL对表型的贡献率为8.80%~18.83%。利用QTLNetwork2.0共检测到4个QTLs,贡献率为7.36%~16.05%,除q LWR-1未被检测到外,其余QTLs与Win QTLcart2.5检测结果吻合,除q LWR-4外,谷粒长宽比增效基因均来自长粒型水稻品种N22;此外还检测到3对上位性QTLs,贡献率为1.12%~4.97%。     

Disruption of the epithelial apical-junctional complex by Helicobacter pylori CagA

Helicobacter pylori translocates the protein CagA into gastric epithelial cells and has been linked to peptic ulcer disease and gastric carcinoma. We show that injected CagA associates with the epithelial tight-junction scaffolding protein ZO-1 and the transmembrane protein junctional adhesion molecule, causing an ectopic assembly of tight-junction components at sites of bacterial attachment, and altering the composition and function of the apical-junctional complex. Long-term CagA delivery to polarized epithelia caused a disruption of the epithelial barrier function and dysplastic alterations in epithelial cell morphology. CagA appears to target H. pylori to host cell intercellular junctions and to disrupt junction-mediated functions.     

Somatic cell hybrid between the established human line D98 (presumptive HeLa) and 3T3

Somatic cell hybrids have been made between an established human cell line with a long culture history and established mouse fibroblast line. When first analyzed, the hybrid cells contained nearly twice as many mouse chromosomes as the mouse parent line and a human chromosome complemnent of about half that of the human parent. There was further loss of human chromosomes on continued cultivation. This behavior resembles that of other human mouse hybrids and appears to be characteristic of the human-mouse combination. However, the number of human chromosomes is greater than in hybrids made from human diploid fibroblasts. Some clones contain more than a haptoid quantity of human DNA per cell and should synthesize a much greater number of human gene products.     

巧用AutoCAD软件的“三维旋转”命令绘制实体课件

巧妙地应用AutoCAD软件的"三维旋转"命令,可以方便快捷地绘制带有倾斜结构及局部剖结构的实体课件,并用两个实例说明了具体的应用方法。     

Disruption of the Dictyostelium myosin heavy chain gene by homologous recombination

The phenomenon of homologous recombination, which allows specific gene conversion and gene insertion, can be a powerful system for the study of eukaryotic cell biology. Data are presented demonstrating that integration of a transfected plasmid by homologous recombination occurs in the motile eukaryotic cell Dictyostelium discoideum. A plasmid carrying a G418 resistance gene and the amino terminal half of the myosin heavy chain gene was used to transfect Dictyostelium. A large fraction of the resultant G418-resistant cells had the plasmid integrated into the single genomic copy of the heavy chain gene. These cells, which fail to express the native myosin but express the myosin fragment, are defective in cytokinesis and become large and multinucleate. In spite of the absence of native myosin, these cells, termed hmm cells, exhibit many forms of cell movement, including membrane ruffling, phagocytosis, and chemotaxis. The hmm cells can aggregate but are blocked at a later stage in the Dictyostelium developmental cycle. The hmm cells revert to the wild-type phenotype. Reversion of the hmm phenotype is due to excision and loss of the transforming plasmid. The revertant cells express native myosin, are G418 sensitive, and have a normal developmental cycle. These results constitute genetic proof that the intact myosin molecule is required for cytokinesis and not for karyokinesis.     

A new DNA marker tightly linked to the fragile X locus (FRAXA)

The fragile X syndrome is the most common cause of familial mental retardation. Genetic counseling and gene isolation are hampered by a lack of DNA markers close to the disease locus. Two somatic cell hybrids that each contain a human X chromosome with a breakpoint close to the fragile X locus have been characterized. A new DNA marker (DXS296) lies between the chromosome breakpoints and is the closest marker to the fragile X locus yet reported. The Hunter syndrome gene, which causes iduronate sulfatase deficiency, is located at the X chromosome breakpoint that is distal to this new marker, thus localizing the Hunter gene distal to the fragile X locus.     

“单片机”教学的思考和探讨

简述＂单片机＂在计算机科学技术专业和电子信息专业占有非常重要的地位,而当今社会所需的单片机开发人员,要求具有一定的实践动手能力,因此单片机的实践教学是整个教学设计中的重要环节。因此要利用现在的教学条件,不断进行单片机实践教学改革。     

Relation between the major histocompatibility (B) locus and autoimmune thyroiditis in obese chickens

Obese strain chickens develop circulating autoantibodies to thyroglobulin and lymphocytic infiltration of their thyroids during aging. Two alleles, B(1) and B(4), are found with high gene frequency at the major histocompatibility (B) locus. Greater pathology and higher antibody titers are observed in B(1)B(1) and B(1)B(4) birds than in their B(4)B(4) siblings.     

A MADS-box gene necessary for fruit ripening at the tomato ripening-inhibitor (rin) locus

Tomato plants harboring the ripening-inhibitor (rin) mutation yield fruits that fail to ripen. Additionally, rin plants display enlarged sepals and loss of inflorescence determinacy. Positional cloning of the rin locus revealed two tandem MADS-box genes (LeMADS-RIN and LeMADS-MC), whose expression patterns suggested roles in fruit ripening and sepal development, respectively. The rin mutation alters expression of both genes. Gene repression and mutant complementation demonstrate that LeMADS-RIN regulates ripening, whereas LeMADS-MC affects sepal development and inflorescence determinacy. LeMADS-RIN demonstrates an agriculturally important function of plant MADS-box genes and provides molecular insight into nonhormonal (developmental) regulation of ripening.