Using affinity capillary electrophoresis to study the interaction of the extracellular binding domain of erythropoietin receptor with peptides.

We have shown that affinity capillary electrophoresis (ACE) can be utilized to screen peptides that bind to the extracellular binding domain of the erythropoietin receptor (EBP). The comparison of the cyclic peptides GGTYSCHFGPLTWVCKPQGG (EMP1) GGTYSCHFGPLTAVCKPQGG (EMP13), and LGRKYSCHFGPLTWVCQPAKKD (EMP37) with the linear peptides HFGPLTWV (EMP26) and FMRF as ACE buffer additives were investigated. When EMP1 and EMP37 were the buffer additives, an abrupt change in the electrophoretic mobility of EBP was observed in the electropherogram. When EMP13, EMP26, and FMRF were examined under identical ACE conditions as EMP1 and EMP37, no significant change in the electrophoretic mobility of EBP was observed. These results correlate well with previously reported IC50 competitive binding data; that is, EMP1 and EMP37 bind to EBP while EMP13 and EMP26 bind very weakly. These observations strongly infer that peptide.EBP dimerization were induced by EMP1, and EMP37 but not by EMP13, EMP26 or FMRF. This ACE method provides a rapid tool for the detection of small peptides or drugs that bind to EBP.     

Effect of Temperature, CO(2) Concentration, and Light Intensity on Oxygen Inhibition of Photosynthesis in Wheat Leaves

The effect of 21% O₂ and 3% O₂ on the CO₂ exchange of detached wheat leaves was measured in a closed system with an infrared carbon dioxide analyzer. Temperature was varied between 2° and 43°, CO₂ concentration between 0.000% and 0.050% and light intensity between 40 ft-c and 1000 ft-c. In most conditions, the apparent rate of photosynthesis was inhibited in 21% O₂ compared to 3% O₂. The degree of inhibition increased with increasing temperature and decreasing CO₂ concentration. Light intensity did not alter the effect of O₂ except at light intensities or CO₂ concentrations near the compensation point. At high CO₂ concentrations and low temperature, O₂ inhibition of apparent photosynthesis was absent. At 3% O₂, wheat resembled tropical grasses in possessing a high rate of photosynthesis, a temperature optimum for photosynthesis above 30°, and a CO₂ compensation point of less than 0.0005% CO₂. The effect of O₂ on apparent photosynthesis could be ascribed to a combination of stimulation of CO₂ production during photosynthesis, and inhibition of photosynthesis itself.     

Production of DON-related trichothecenes byFusarium graminearum Schw from Krasnodarski krai of the USSR

34Fusarium graminearum Schw isolates produced 4-deoxynivalenol to form significant amounts of 4, 7 — dideoxynivalenol and lesser amounts of 4 — deoxynivalenol monoacetates on grain substratesin vitro. This is the first report on the capability a large group of naturally occurring isolates to produce 4,7-dideoxynivalenol. The average levels of 4,7-dideoxynivalenol on rice, corn, barley, and wheat as a substrate were respectively 26.8, 14.0, 12.8, and 10.5% of the level of 4-deoxynivalenol. 4, 7 — dideoxynivalenol was present in all examined naturally contaminated wheat kernel samples at levels of 1.7 to 7.9% of the level of 4-deoxynivalenol. These findings suggest that more attention should be given to the occurrence of 4,7-dideoxynivalenol in cereals.     

Variation in the ribosomal internal transcribed spacers (ITS1 and ITS2) among eight taxa of the Mimulus guttatus species complex

The internal transcribed spacer region (ITS1 and ITS2) of the 18S-25S nuclear ribosomal DNA sequence and the intervening 5.8S region were sequenced from three individuals in each of eight taxa of the Mimulus guttatus species complex. Three discrete variants, or "types," of ITS sequences were found, among which 30%-40% of sites differed, compared with 1%-2% within types. Dot plots indicate that these types were not related by conspicuous rearrangements or inversions. More than one ITS type was often found in the same taxon, and two of three ITS types span species boundaries, indicating their presence prior to speciation. These ITS sequences showed essentially no positional homology with the nearest sequenced relative, tomato. In contrast, the 5.8S region was relatively unvaried, with 8 of 162 sites varied in the sample among all eight taxa. The phylogeny inferred by the most common ITS sequence type, rooted by the two other ITS types, agreed with isozymes in showing the distinctness of M. nudatus, M. laciniatus, and M. tilingii from the other five taxa.      

Humanized OKT3 antibodies: successful transfer of immune modulating properties and idiotype expression.

Antibodies that possess the Ag-binding regions of OKT3 within the context of a human framework (Hu-OKT3 Ab) offer distinct advantages for optimizing anti-CD3 mAb therapy. First, manipulation of Ab genes to produce humanized Ab that retain Ag-binding activity may circumvent antigenicity problems. Second, Ab gene engineering provides a means for modifying functional properties, including T cell activation and immune suppression. The purpose of this study was to determine the functional properties of Hu-OKT3 Ab and to compare the functional properties and idiotypes of Hu-OKT3 Ab to those of murine OKT3. Three Hu-OKT3 IgG4 Ab, a chimeric OKT3 antibody (cOKT3-1) (grafted sequences comprising all OKT3 VH and VL regions) and two complementarity determining region (CDR)-grafted antibodies, gOKT3-5 and gOKT3-6 (grafted sequences comprising only OKT3 VH and VL CDR and some framework amino acids, were analyzed. Initial studies demonstrated that the cOKT3 and gOKT3-5 Ab bound selectively to T cells and competitively inhibited OKT3-FITC binding with avidities similar to that of murine OKT3. Binding avidity of the gOKT3-6 Ab was markedly less than that of the other two Hu-OKT3 Ab. Serologic analysis suggested that cOKT3 and gOKT3-5 Ab possess idiotypes (combining sites) similar to murine OKT3. T cell activation potency of all three Hu-OKT3 Ab was assessed by proliferation, induction of activation marker expression (IL-2R and Leu 23), and lymphokine production (TNF-alpha and IFN-gamma). The cOKT3 and gOKT3-5 Ab demonstrated T cell activation potencies similar to murine OKT3 as assessed by each parameter. CD3 coating and modulation by these two Ab was effective but somewhat less potent than that observed with OKT3. Finally, cOKT3 and gOKT3-5 Ab both inhibited CTL activity comparably to murine OKT3. In conclusion, these studies indicate that gOKT3-5 and cOKT3 Ab possess immune modulating properties similar to murine OKT3 and thus offer attractive alternatives to murine OKT3 for in vivo therapy.     

中国小菇属十个新记录种

报道了小菇科小菇属真菌10个中国新记录种,香菌组：橙盖小菇Mycena aurantiidisca、黄白小菇Mycena flavoalba、粉黄小菇Mycena floridula;棘刺组：异刺小菇Mycena heteracantha;纤柄组：碱味小菇Mycena amygdalina;脆足组：粉被小菇Mycena zephirus;冬生组：绣线菊小菇Mycena speirea、冬生小菇Mycena hiemalis;小菇组：绒柄小菇Mycena flos-nivium,分别来自吉林等11个省份、自治区。提供了每个物种的形态描述和线条图,以及与相近种的讨论。共计90条自测及下载ITS序列,在采用贝叶斯法和最大似然法构建的小菇属系统发育树中,新记录种均得到分子数据支持。凭证标本存放于吉林农业大学菌物标本馆（HMJAU）。     

Reconstructing paternal genotypes to infer patterns of sperm storage and sexual selection in the hawksbill turtle

Postcopulatory sperm storage can serve a range of functions, including ensuring fertility, allowing delayed fertilization and facilitating sexual selection. Sperm storage is likely to be particularly important in wide‐ranging animals with low population densities, but its prevalence and importance in such taxa, and its role in promoting sexual selection, are poorly known. Here, we use a powerful microsatellite array and paternal genotype reconstruction to assess the prevalence of sperm storage and test sexual selection hypotheses of genetic biases to paternity in one such species, the critically endangered hawksbill turtle, Eretmochelys imbricata. In the majority of females (90.7%, N = 43), all offspring were sired by a single male. In the few cases of multiple paternity (9.3%), two males fertilized each female. Importantly, the identity and proportional fertilization success of males were consistent across all sequential nests laid by individual females over the breeding season (up to five nests over 75 days). No males were identified as having fertilized more than one female, suggesting that a large number of males are available to females. No evidence for biases to paternity based on heterozygosity or relatedness was found. These results indicate that female hawksbill turtles are predominantly monogamous within a season, store sperm for the duration of the nesting season and do not re‐mate between nests. Furthermore, females do not appear to be using sperm storage to facilitate sexual selection. Consequently, the primary value of storing sperm in marine turtles may be to uncouple mating and fertilization in time and avoid costly re‐mating.     

川芎嗪对Aβ25-35诱导体外大鼠海马神经元细胞凋亡的影响

本文通过Aβ25-35诱导体外原代培养的SD乳大鼠海马神经元,建立Aβ毒性损伤细胞模型,结合AnnexinV-FITC/PI荧光双染法流式细胞术、MTT比色法、实时荧光定量PCR及Western blot方法检测川芎嗪(tetrameth-ylpyrazine,TMP)对原代培养的海马神经元细胞活性、早期凋亡率和Bax、Bcl-2基因表达的影响。结果显示川芎嗪高、中剂量可明显增强细胞活性,增加神经元细胞的存活率(P<0.01),可显著抑制海马神经元细胞早期凋亡(P<0.01),抑制凋亡蛋白Bax的表达(P<0.01),增强抗凋亡蛋白bcl-2的表达(P<0.01)。川芎嗪可通过调节Bax/Bcl-2平衡抵抗Aβ25-35诱导的海马神经元凋亡,降低Aβ的神经元毒性,对海马神经元损伤有明显的保护作用。