The first potassium channel toxin from the venom of the Iranian scorpion Odonthobuthus doriae

The very first member of K(+) channels toxins from the venom of the Iranian scorpion Odonthobuthus doriae (OdK1) was purified, sequenced and characterized physiologically. OdK1 has 29 amino acids, six conserved cysteines and a pI value of 4.95. Based on multiple sequence alignments, OdK1 was classified as alpha-KTx 8.5. The pharmacological effects of OdK1 were studied on six different cloned K(+) channels (vertebrate Kv1.1-Kv1.5 and Shaker IR) expressed in Xenopus laevis oocytes. Interestingly, OdK1 selectively inhibited the currents through Kv1.2 channels with an IC50 value of 183+/-3 nM but did not affect any of the other channels.     

Transgenic Rice Plants Produced by PEG-Mediated Plasmid Uptake into Protoplasts

Embryogenic cell suspension cultures were obtained from calli developed from mature rice seeds of a Japonica type Itahan cultivar, Roncarolo. Protoplasts were isolated and transformed by PEG-treated method with plasmid pHP23 carrying the NPT Ⅱ gene which encodes resistance to antibiotic G-418. Protoplast-derived colonies were selected in presence of the inhibitor. Plants were regenerated and transplanted into soil in the green house. The presence of foreign gene in the regenerated plants was verified by PCR and Southern analysis.     

Microsatellite markers for Bromus tectorum (cheatgrass)

Bromus tectorum (cheatgrass) is a flourishing invasive weed in the western United States. The objective of our study is to characterize its genetic diversity. We made a B. tectorum genomic library in lambda phage and screened approximately 4000 clones for poly CA and poly CT dinucleotide repeats. Of 38 sequences with dinucleotide repeats isolated from the library, we designed primer sets for 18 loci. A preliminary screen of 40 individuals from four populations indicated that seven loci were polymorphic. These loci will be valuable for elucidation of cheatgrass genetic diversity and population structure.     

Survival analysis in clinical trials: past developments and future directions

The field of survival analysis emerged in the 20th century and experienced tremendous growth during the latter half of the century. The developments in this field that have had the most profound impact on clinical trials are the Kaplan-Meier (1958, Journal of the American Statistical Association 53, 457-481) method for estimating the survival function, the log-rank statistic (Mantel, 1966, Cancer Chemotherapy Report 50, 163-170) for comparing two survival distributions, and the Cox (1972, Journal of the Royal Statistical Society, Series B 34, 187-220) proportional hazards model for quantifying the effects of covariates on the survival time. The counting-process martingale theory pioneered by Aalen (1975, Statistical inference for a family of counting processes, Ph.D. dissertation, University of California, Berkeley) provides a unified framework for studying the small- and large-sample properties of survival analysis statistics. Significant progress has been achieved and further developments are expected in many other areas, including the accelerated failure time model, multivariate failure time data, interval-censored data, dependent censoring, dynamic treatment regimes and causal inference, joint modeling of failure time and longitudinal data, and Baysian methods.     

Synthesis of novel steroidal agonists,partial agonists,and antagonists for the glucocorticoid receptor

Adverse effects of glucocorticoids could be limited by developing new compounds that selectively modulate anti-inflammatory activity of the glucocorticoid receptor (GR). We have synthesized a novel series of steroidal GR ligands, including potent agonists, partial agonists and antagonists with a wide range of effects on inhibiting secretion of interleukin-6. Some of these new ligands were designed to directly impact conformational stability of helix-12, in the GR ligand-binding domain (LBD). These compounds modulated GR activity and glucocorticoid-induced gene expression in a manner that was inversely correlated to the degree of inflammatory response. In contrast, compounds designed to directly modulate LBD epitopes outside helix-12, led to dissociated levels of GR-mediated gene expression and inflammatory response. Therefore, these new series of compounds and their derivatives will be useful to dissect the ligand-dependent features of GR signaling specificity.     

Extraordinary proliferation of microorganisms in aposymbiotic pea aphids,Acyrthosiphon pisum

Aposymbiotic pea aphids, which were deprived of their intracellular symbiotic bacterium, Buchnera, exhibit growth retardation and no fecundity. High performance liquid chromatographic (HPLC) analysis revealed that these aposymbiotic aphids, when reared on broad bean plants, accumulated a large amount of histamine. To assess the possibility of extraordinary proliferation of microorganisms other than Buchnera, we enumerated eubacteria and fungi in aphids using the real-time quantitative PCR method that targets genes encoding small-subunit rRNAs. The result showed that these microorganisms were extremely abundant in the aposymbiotic aphids reared on plants. Microbial communities in aposymbiotic aphids were further profiled by phylogenetic analysis of small-subunit rDNAs. Of 172 nonchimeric sequences of fungal 18S rDNAs, 138 (80.2%) belonged to the phylum Ascomycota. Among them, 21 clustered within a monophyletic group consisting of insect-pathogenic fungi and yeast-like symbionts of homopteran insects. Thirty-one (18.0%), two (1.2%), and one (0.6%) clones were clustered within the Basidiomycota, Zygomycota, and Oomycota, respectively. Of 167 nonchimeric sequences of eubacterial 16S rDNAs, 84 (50.3%) belonged to the gamma-subdivision of Proteobacteria to which most primary endosymbionts of insects and prolific histamine producers belong. Forty (24.0%), 25 (15.0%), 10 (6.0%), and five (3.0%) clones were clustered within alpha-Proteobacteria, Cytophaga-Flavobacterium-Bacteroides (CFB) group, Actinobacteria, and beta-Proteobacteria, respectively. Three had no phylogenetic association with known taxonomic divisions. None of the sequences studied in this study coincided exactly with those deposited in GenBank.     

恶性肿瘤组织中结核杆菌DNA的检测

目的　探讨结核杆菌感染与恶性肿瘤的关系。方法　采用多聚酶链反应（ＰＣＲ） 技术检测两种恶性肿瘤组织中结核杆菌ＤＮＡ（ＴＢ－ ＤＮＡ） 。结果４１ 例恶性肿瘤组织中检出ＴＢ－ ＤＮＡ 阳性患者８ 例,占１９．５ ％ ,且ＴＢ－ＤＮＡ 阳性患者肿瘤发病部位基本与结核病的好发部位一致。结论 结核杆菌感染可能与一些恶性肿瘤存在特殊相关性。     

Estimating regression parameters and degree of dependence for multivariate failure time data

Multivariate failure time data are frequently encountered in longitudinal studies when subjects may experience several events or when there is a grouping of individuals into a cluster. To take into account the dependence of the failure times within the unit (the individual or the cluster) as well as censoring, two multivariate generalizations of the Cox proportional hazards model are commonly used. The marginal hazard model is used when the purpose is to estimate mean regression parameters, while the frailty model is retained when the purpose is to assess the degree of dependence within the unit. We propose a new approach based on the combination of the two aforementioned models to estimate both these quantities. This two-step estimation procedure is quicker and more simple to implement than the EM algorithm used in frailty models estimation. Simulation results are provided to illustrate robustness, consistency, and large-sample properties of estimators. Finally, this method is exemplified on a diabetic retinopathy study in order to assess the effect of photocoagulation in delaying the onset of blindness as well as the dependence between the two eyes blindness times of a patient.     

PERMANENT GENETIC RESOURCES: Development of microsatellite markers and analysis of their inheritance in the Australian reptile tick, Bothriocroton hydrosauri

Despite long-term study, the mechanism explaining the parapatric distribution of two Australian reptile tick species is not understood. We describe the development of primers amplifying 10 microsatellite Bothriocroton hydrosauri loci, for the study of population structure and dispersal patterns of this tick. The numbers of alleles per locus ranged from two to seven in ticks from the study site, and the observed heterozygosity between 0.28 and 0.69. Pedigree analysis indicates that one locus is inherited in a non-Mendelian manner in three families, which was not explained by null allele presence.