Mitochondrial DNA is a major cellular target for a dihydrodiol-epoxide derivative of benzo[a]pyrene

When mammalian cell cultures are exposed for 2 hours to (+/-)-7 beta, 8 alpha-dihydroxy-9 alpha, 10 alpha-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene, a mutagenic and carcinogenic derivative of benzo[a]pyrene, the extent of covalent modificationof mitochondrial DNA is 40 to 90 times greater than that of nuclear DNA. Evidence is presented that this reflects the lipophilic character of the derivative and the very high ratio of lipid to DNA in mitochondria. These results suggest that mitochondrial DNA may be an important cellular target of chemical carcinogens.     

苯并[a]芘对毛霉EPS特征的影响

为了明确毛霉胞外聚合物(Extracellular polymertic substances,EPS)在多环芳烃修复中的作用机理,研究了不同浓度苯并[a]芘(BaP)诱导下毛霉EPS的提取量(TOC)和主要化学成分含量(糖类、蛋白质、腐植酸和DNA)的变化规律,采用三维荧光光谱(3D-EEM)、傅里叶红外光谱(FTIR)和扫描电镜(SEM)等方法分析了不同条件下EPS蛋白含量和自身结构的变化。结果表明,当BaP浓度为40 mg·L~(-1)时,单位生物量所产生的毛霉EPS的提取量、糖类含量、蛋白质含量和腐植酸含量均达到最大值,分别为1 407.22 mg·g-1、700 g·g-1、564 g·g-1和174 g·g-1;3D-EEM结果显示,当BaP浓度为40 mg·L~(-1)时,荧光类蛋白质(峰A和峰B)强度分别达到最大值68.91 a.u和245.6 a.u;FTIR分析结果表明,在BaP的诱导下,与空白相比,EPS的细胞质蛋白质酰胺Ⅰ带和酰胺Ⅱ带向长波方向发生了红移现象;SEM分析结果显示,随BaP浓度的增大,毛霉EPS表面逐渐呈现板结现象,当BaP浓度为40 mg·L~(-1)时,毛霉EPS呈毛绒状,孔隙达到最大。以上分析结果表明,BaP破坏毛霉EPS原有结构,低浓度BaP促进真菌EPS的分泌,EPS中的蛋白质和多糖在毛霉代谢降解BaP过程中起到了主要作用。     

苯并芘[a]不同污染方式对黄褐土微生物区系的影响

为研究苯并[a]芘(B[a]P)在土壤中逐步累积后对土壤微生物区系的影响,试验采用低剂量叠加的方式模拟B[a]P在黄褐土中的累积过程,研究B[a]P不同污染方式对土壤B[a]P含量和微生物可培养种群数量的影响。结果表明:在B[a]P累积和一次污染方式下,土壤B[a]P可提取态和有效含量随培养时间的延长而降低,培养前期(1~28 d)下降速率较快,后期(28~56 d)下降速率减缓。B[a]P累积污染在整个培养期内显著地增加了土壤可培养细菌的数量,降低了真菌和放线菌的数量;一次污染在初期降低了可培养细菌和放线菌的数量,增加了真菌的数量。B[a]P累积污染对土壤微生物数量的抑制率为放线菌真菌细菌;一次污染对土壤微生物数量的抑制率为放线菌细菌真菌。放线菌对土壤B[a]P污染最为敏感,且与土壤B[a]P含量的相关性高于细菌和真菌,可作为多环芳烃类污染物污染土壤的生物学指标。累积污染以低剂量叠加方式研究了土壤微生物区系对B[a]P污染的响应,反映了B[a]P在实际土壤中的环境风险。     

打叶复烤各工序对卷烟主流烟气氢氰酸与苯并[a]芘、巴豆醛释放量的影响研究

选择红花大金元B3F、C3F、X2F 烟叶,对打叶复烤各工序卷烟主流烟气氢氰酸、苯并[a]芘和巴豆醛释放量进行研究。结果表明：各工序上部烟叶卷烟样品的HCN释放量最高,下部烟叶的最低,一润工序较处理前较大幅度提高了上部烟叶氢氰酸释放量;二润工序与一润工序相比,下部烟叶苯并[a]芘释放量降低9.36%;复烤工序与二润工序相比,下部烟叶巴豆醛释放量降低14.96%,中部烟叶苯并[a]芘释放量降低17.29%。综合结果,上部烟叶各工序间样品的主流烟气3种物质的变化强度都明显高于下部烟叶。     

Binding of a cytosolic protein to the iron-responsive element of human ferritin messenger RNA

The human ferritin H chain messenger RNA contains a specific iron-responsive element (IRE) in its 5' untranslated region, which mediates regulation by iron of ferritin translation. An RNA gel retardation assay was used to demonstrate the affinity of a specific cytosolic binding protein for the IRE. A single-base deletion in the IRE eliminated both the interaction of the cytoplasmic protein with the IRE and translational regulation. Thus, the regulatory potential of the IRE correlates with its capacity to specifically interact with proteins. Titration curves of binding activity after treatment of cells with an iron chelator suggest that the factor acts as a repressor of ferritin translation.     

一株土著B[a]P降解菌的筛选及降解特性研究

通过在液体培养基中添加苯并[a]芘(B[a]P)作为唯一碳源反复驯化培养,从长期受石油烃和多环芳烃(PAHs)污染的土壤中分离出8株能够降解B[a]P的细菌,其中一株细菌(命名为BB-1)具有最大降解效果。采用16s RNA基因测序结果表明,BB-1与巨大芽孢杆菌(Bacillus megaterium)同源性为100%。为了研究BB-1的降解特性,在pH7.0、30℃条件下培养8 d,菌株B[a]P的降解率高达66.36%。为了考察培养基初始pH和外加蔗糖浓度对BB-1降解B[a]P的影响,30℃下振荡培养8 d,当设置培养基初始pH为4.0、6.0、8.0和10.0时,BB-1对B[a]P的降解率分别为12.14%、39.61%、55.21%和30.03%,可见pH为8.0时其降解效果最优;当添加0.1%蔗糖和0.5%蔗糖为外加碳源时,菌株BB-1对B[a]P的降解率分别为70.56%和74.89%,表明0.5%蔗糖的降解效果最优。     

土著B[a]P降解菌群的富集及最佳降解条件研究

为了获得能够降解苯并[a]芘(BaP)的微生物菌群,为生物修复多环芳烃污染的土壤提供菌种资源,本试验从长期石油污染的土壤中,富集了一个能够降解BaP的微生物菌群,并研究了其最佳降解条件,通过高通量测序研究了其群落结构。该菌群可以在15 d内将30 mg·L^-1的BaP降解33.34%。高通量测序的结果表明,该菌群主要由Bacillus、Zobellella、Gordonia和Rheinheimera组成,其中Bacillus是主要的降解菌。试验结果表明,该菌群的最佳降解条件为1%盐度,酵母浓度为80 mg·L^-1,pH值7.0。该菌群对芘、菲、荧蒽等多环芳烃也有一定的降解效果,其中荧蒽的降解效果最好,降解率达到99%。试验结果表明,该菌群在实际应用中具有很大的潜力。     

Correlated measurements of DNA, RNA, and protein in individual cells by flow cytometry

A cytochemical method was developed to differentially stain cellular DNA, RNA, and proteins with fluorochromes Hoechst 33342, pyronin Y, and fluorescein isothiocyanate, respectively. The fluorescence intensities, reflecting the DNA, RNA, and protein content of individual cells, were measured in a flow cytometer after sequential excitation by three lasers tuned to different excitation wavelengths. The method offers rapid analysis of changes in the cellular content of RNA and protein as well as in the RNA-protein, RNA-DNA, and protein-DNA ratios in relation to cell cycle position for large cell populations. An analysis of cycling cell populations (exponentially growing CHO cultures) and noncycling CHO cells arrested in the G1 phase by growth in isoleucine-free medium demonstrated the potential of the technique.     

beta-Glucuronidase catalyzed hydrolysis of benzo(a)pyrene-3-glucuronide and binding to DNA

beta-Glucuronidase catalyzes the hydrolysis of benzo[a]pyrene-3-glucuronide to 3-hydroxybenzo[a]pyrene. During the enzymatic hydrolysis, a benzo[a]pyrene derivative is formed which binds to DNA to a far greater extent than either the 3-hydroxybenzo[a]pyrene or its glucuronide. These results suggest that conjugates of benzo(a)pyrene may be converted by beta-glucuronidase at intracellular and organ sites distal to the initial sites of oxygenation and conjugation of benzo(a)pyrene to activated intermediates that are possibly carcinogenic.     

Unexpectedly high levels of HIV-1 RNA and protein synthesis in a cytocidal infection

The expression of a laboratory strain of HIV-1 (HTLV-IIIB) has been studied in mitogen-stimulated peripheral blood lymphocytes (PBLs) and in two lymphoid cell lines (CEM cells and C8166 cells). HIV-expressing cells contained from 300,000 to 2,500,000 copies of viral RNA per cell. Near-synchronous expression of an active infection could be achieved in C8166 cells. In these cells, the high copy numbers of viral RNA used as much as 40% of total protein synthesis for the production of viral gag protein, with high levels of viral RNA and protein synthesis preceding cell death by 2 to 4 days.     

高蛋白高产多抗杂交水稻新组合汕优联合2号的选育

利用不育系珍汕97A与自育抗病抗寒恢复系UN12配组，育成高蛋白优质多抗杂交水稻新组合汕优联合2号。经1999～2000年贵州省杂交水稻区试鉴定，汕优联合2号平均产量8269．5k／hm^2，比对照增产7％。2001年在5个不同生态区进行生产试验，平均产量8838．0kg／hm^2，比相应综合对照增产2．67％。结果表明，汕优联合2号比贵州省目前推广的优良组合增产，抗寒好、结实率比对照高3％。稻瘟病接种和自然鉴定结果表明，汕优联合2号1～3级，抗稻瘟病。米质理化测试指标和食味鉴评结果，米质优，有9项指标达部颁优质米标准二级以上，特别是蛋白质含量高，达12．2％。汕优联合2号于2002年2月通过贵州省农作物品种审定委员会审定．可在贵州省中低海拔地区推广。     

Binding of ARF and beta-COP to Golgi membranes: possible regulation by a trimeric G protein

The binding of cytosolic coat proteins to organelles may regulate membrane structure and traffic. Evidence is presented that a small guanosine triphosphate (GTP)-binding protein, the adenosine diphosphate ribosylation factor (ARF), reversibly associates with the Golgi apparatus in an energy, GTP, and fungal metabolite brefeldin A (BFA)-sensitive manner similar to, but distinguishable from, the 110-kilodalton cytosolic coat protein beta-COP. Addition of beta gamma subunits of G proteins inhibited the association of both ARF and beta-COP with Golgi membranes that occurred upon incubation with guanosine 5'-O-(3-thiotriphosphate) (GTP-gamma-S). Thus, heterotrimeric G proteins may function to regulate the assembly of coat proteins onto the Golgi membrane.     

优质蛋白玉米黔单11号引种高产栽培技术

通过对优质蛋白杂交玉米良种黔单11号引种高产栽培试验，筛选出适宜我区生态条件下的优化栽培技术方案．提出了高产栽培技术，为该品种在我区的应用提供指导。     

苯并[a]芘对真鲷(Pagrosomus major)血细胞DNA损伤的慧星实验研究

对取自厦门海域养殖鱼排的真鲷以0.8、1.4、2.0μg.L-1不同浓度苯并[a]芘(BaP)分别进行4、24h的暴露染毒,用改进的慧星实验技术研究了BaP对真鲷血细胞DNA的损伤。结果表明:(1)通过慧星实验获得的DNA损伤指标显示,与空白对照组相比,暴露染毒组血细胞DNA均受到损伤且损伤存在显著性差异(P<0.01),剂量-效应关系明显,DNA损伤随着染毒时间的延长明显增加。(2)优化了适合检测真鲷血细胞DNA损伤的彗星实验电泳条件:20V、300mA、20min。(3)在样本数量较多的情况下,用细胞培养板板盖铺单层胶的彗星实验检测方式与用载玻片铺3层胶的“三明治”方式相比,具有操作简便、节省时间、制胶过程凝胶不易破损、重复性好等优点。     

Scintigraphy of normal mouse ovaries with monoclonal antibodies to ZP-2, the major zona pellucida protein

The zona pellucida is an extracellular glycocalyx, made of three sulfated glycoproteins, that surrounds mammalian oocytes. Parenterally administered monoclonal antibodies specific for ZP-2, the most abundant zona protein, localize in the zona pellucida. When labeled with iodine-125, these monoclonal antibodies demonstrate a remarkably high target-to-nontarget tissue ratio and provide clear external radioimaging of ovarian tissue.     

高产高蛋白大豆冀豆12号育种研究

通过育种技术的应用与创新，打破大豆蛋白质与产量的负相关性，育成我国蛋白质产量最高、适应性广的大豆新品种——冀豆12号。研究分析了冀豆12号育种过程中的选择方法与性状相关。结果表明：形态性状及生理性状的间接选择对蛋白质和产量的提高是有效的，单株分枝多、单荚粒数少、粒大、主茎荚数与分枝荚数比值较低、生殖生长期与全生育期比值小的后代蛋白质含量较高；生态鉴定与分子标记鉴定适于抗性与适应性选育。     

Widespread distribution of brain dopamine receptors evidenced with [125I]iodosulpride, a highly selective ligand

The new benzamide derivative [125I]iodosulpride is a highly sensitive and selective ligand for D-2 dopamine receptors and displays a very low nonspecific binding to membrane or autoradiographic sections. On autoradiographic images, D-2 receptors are present not only in well-established dopaminergic areas but also, in a discrete manner, in a number of catecholaminergic regions in which the dopaminergic innervation is still unknown, imprecise, or controversial, as in the sensorimotor cerebral cortex or cerebellum. This widespread distribution suggests larger physiological and pathophysiological roles for cerebral dopamine receptors than was previously thought.     

HRR25, a putative protein kinase from budding yeast: association with repair of damaged DNA

In simple eukaryotes, protein kinases regulate mitotic and meiotic cell cycles, the response to polypeptide pheromones, and the initiation of nuclear DNA synthesis. The protein HRR25 from the budding yeast Saccharomyces cerevisiae was defined by the mutation hrr25-1. This mutation resulted in sensitivity to continuous expression of the HO double-strand endonuclease, to methyl methanesulfonate, and to x-irradiation. Homozygotes of hrr25-1 were unable to sporulate and disruption and deletion of HRR25 interfered with mitotic and meiotic cell division. Sequence analysis revealed two distinctive regions in the protein. The NH2-terminus of HRR25 contains the hallmark features of protein kinases, whereas the COOH-terminus is rich in proline and glutamine. Mutations in HRR25 at conserved residues found in all protein kinases inactivated the gene, and these mutants exhibited the hrr25 null phenotypes. Taken together, the hrr25 mutant phenotypes and the features of the gene product indicate that HRR25 is a distinctive member of the protein kinase superfamily.     

[a,b]上参数为λ(t)的截尾泊松过程及泊松流的分布

在原有泊松过程定义的基础上,提出了一种新的定义———[a,b]上参数为λ(t)的截尾泊松过程,并得出且论证了[a,b]上参数为λ(t)的截尾泊松过程相关性质及其泊松流的分布。