Reaction mechanism of surfactant‐sensitized chemiluminescence of bis(2,4,6‐trichlorophyenyl) oxalate and hydrogen peroxide induced by gold nanoparticles

The chemiluminescence (CL) of bis(2,4,6‐trichlorophyenyl) oxalate with hydrogen peroxide in the present of cationic surfactant and gold nanoparticles was studied. The CL emission was obviously enhanced in the presence of surfactant at a suitable concentration, with a synergetic catalysis effect exhibited. Different sizes of gold nanoparticles (15 and 50 nm) showed different effects on CL intensity. Mechanisms of the CL reaction and sensitization effect are discussed. Copyright © 2008 John Wiley & Sons, Ltd.     

Pre‐copulation intervals,copulation frequencies,and initial progeny sex ratios in two biotypes of whitefly,Bemisia tabaci

The whitefly Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) is a species complex, and its systematic classification requires controlled crossing experiments among its genetic groups. Accurate information on pre‐copulation intervals, copulation frequencies, and initial frequency of egg fertilization of newly emerged adults is critical for designing procedures for collecting the virgin adults necessary for these experiments. In the literature, considerable variation is reported between B. tabaci populations, with respect to the length of the pre‐copulation interval and the initial frequency of egg fertilization. Here, we used a video‐recording method to observe continuously the copulation behaviour of the Mediterranean/Asia Minor/Africa (B biotype) and the Asia II (ZHJ1 biotype) groups of B. tabaci. We also recorded the initial frequency of egg fertilization, as determined by the sex of the progeny. When adults were caged in female–male pairs on leaves of cotton plants, the earliest copulation events occurred 2–6 h after emergence; at 12 h after emergence 56–84% of the females had copulated at least once, and nearly all (92–100%) had copulated at least once by 36 h after emergence. Both females and males copulated repeatedly. Approximately 80 and 20% of copulation events occurred during the photophase and scotophase, respectively. By 72 h post‐emergence, the females of the B and ZHJ1 biotypes had copulated on average 6.1 and 3.9 times, respectively. When adults were caged in groups on plants 1–13 h after emergence, 30–35% of the eggs deposited during this period were fertilized, and approximately 90% of females were fertilized by the end of the 13 h. Although timing of copulation differed in detail between the two genetic groups, the results demonstrate that B. tabaci adults can start to copulate as early as 2–6 h post‐emergence and the majority of females can become fertilized on the day that they emerge.     

我国某些常见化石硅藻的环境分析

本文详细研究了中国海表层沉积物中的常见化石硅藻,结果表明,这些种的分布范围及数量变化随环境的不同而变化。因此,根据柱状样品中这些种类数量的变化,能够推断古气候变化,恢复古地理环境,再现海平面波动历程,进而划分、对比第四系地层。     

Potentiation of harringtonine cytotoxicity by calcium antagonist diltiazem and biscoclaurine alkaloid cepharanthine in adriamycin-resistant P388 murine leukemia and K562 human leukemia cells

Harringtonine showed cross resistance in adriamycin-resistant murine leukemia P388 (P388/ADM) and human leukemia K562 (K562/ADM) cells. The relative resistance of the P388/ADM and K562/ADM cells to harringtonine was about 7 and 40, respectively. Calcium influx blockers, diltiazem and the biscoclaurine alkaloid cepharanthine enhanced the cytotoxicity of harringtonine in P388/ADM and K562/ADM cells. The extent of enhancement was different for the two drugs, and up to a 9- to 10-fold increase in harringtonine cytotoxicity occurred in P388/ADM cells, and 14- to 22-fold enhancement in K562/ADM cells with diltiazem or cepharanthine. Harringtonine resistance of P388/ADM was circumvented completely, and the resistance of K562/ADM was circumvented partially, by diltiazem or cepharanthine. The mechanism of enhanced cytotoxicity by diltiazem and cepharanthine is probably inhibition of active efflux of harringtonine in P388/ADM and K562/ADM cells.     

云南呈贡梁王山现代花粉雨的研究

本文通过对云南呈贡梁王山5块表土分析,初步研究了主要植物花粉的百分含量与其植物覆盖率之间的数量关系,并用校正系数R值表示。按照R值的大小,分为两组:R>1属于超代表性,包括有松、桤木、马桑、蒿和部分蕨类植物;R<1属于低代表性,包括有油杉、栲和石栎、滇青冈、栎、铁仔。在分析松粉分布特征基础上,认为昆明地区西风急流对松粉的传播是主要因素。     

The SV40 TC-II(kappa B) enhanson binds ubiquitous and cell type specifically inducible nuclear proteins from lymphoid and non-lymphoid cell lines.

We have characterized the complexes resulting from the specific binding in vitro of proteins present in nuclear extracts of several lymphoid and non-lymphoid cell lines to the TC-I and TC-II sequences of the simian virus 40 (SV40) enhancer. No proteins could be detected, binding selectively to the TC-I sequence, but two proteins TC-IIA and TC-IIB were identified interacting specifically with both the TC-II/kappa B enhanson, 5'-GGAAAGTCCCC-3' (important for the activity of the SV40 enhancer in vivo), and with the related H-2Kb enhanson, 5'-TGGGGATTCCCCA-3'. The binding of these two proteins to mutated TC-II enhansons correlates with the effect of these mutations in vivo, suggesting that both proteins may be important for SV40 enhancer activity. The TC-IIA binding activity was present in nuclear extracts of mature lymphoid B cells and was increased in pre-B cell nuclear extracts by lipopolysaccharide (LPS) and cycloheximide treatment. Furthermore, complex formation between the TC-IIA protein and the TC-II enhanson was efficiently competed by the kappa B motif from the kappa chain enhancer, indicating that TC-IIA is the NF-kappa B factor or a closely related protein. However, in contrast to previous reports, a TC-IIA/NF-kappa B-like protein whose properties could not be distinguished from those of the TC-IIA protein present in lymphoid B cells, was found in nuclear extracts of several untreated non-lymphoid cell lines, notably of HeLa cells, but not of undifferentiated F9 embryonal carcinoma (EC) cells [F9(ND)]. The TC-IIA binding activity which was moderately increased in HeLa cell nuclear extracts by 12-O-tetradecanoylphorbol-13-acetate (TPA) and/or cycloheximide treatment could be induced in nuclear extracts of F9(ND) cells by cycloheximide, but not by TPA. Moreover, the TC-IIA binding activity could be induced in cytosolic fractions from F9(ND) cells by treatment with deoxycholate, indicating that these cells contain an inhibitor protein similar to the previously described NF-kappa B inhibitor, I kappa B. The second TC-II enhanson binding protein, TC-IIB, which could be clearly distinguished from the TC-IIA/NF-kappa B-like protein, by a number of differential properties, resembles the previously described KBF1/H2TF1 protein as it binds with a higher affinity to the H-2Kb enhanson than to the TC-II/kappa B enhanson, and its pattern of methylation interference on the H-2Kb and TC-II/kappa B enhansons is identical to that reported for the KBF1/H2TF1 protein.(ABSTRACT TRUNCATED AT 400 WORDS)     

Modelling basic features of specificity in the binding of a dicationic steroid diamine to double-stranded oligonucleotides.

An investigation of the intrinsically preferred binding modes of a steroid diamine, dipyrandium, to the double-stranded hexanucleotides d(TATATA)2, d(ATATAT)2, and d(CGCGCG)2 is carried out by the energy minimization procedure JUMNA. Several alternative binding modes are compared: groove binding in which the conformation of the oligonucleotide remains close to that of B-DNA, intercalation between base-pairs and interaction with variously kinked structures in which base pairs of dinucleoside steps open towards the groove in which the binding occurs. The favored binding configuration occurs at the d(TpA) step of the AT kinked nucleotides in which the kink opens the base pairs towards the minor groove. Thus, for the d(T1A2T3A4T5A6)2 sequences the preferred complexation involves the kink at the T3A4 step facing the cyclohexane rings A, B, and C of the ligand. For the d(A1T2A3T4A5T6)2 sequence, the kink occurs at the T2A3 step facing the cationic pyrrolidine ring linked to ring A. The binding of dipyrandium to d(CGCGCG)2 is found to be considerably less favourable than for either of the two (AT) sequences.