Development of an Automated and Sensitive Microfluidic Device for Capturing and Characterizing Circulating Tumor Cells (CTCs) from Clinical Blood Samples

Current analysis of circulating tumor cells (CTCs) is hindered by sub-optimal sensitivity and specificity of devices or assays as well as lack of capability of characterization of CTCs with clinical biomarkers. Here, we validate a novel technology to enrich and characterize CTCs from blood samples of patients with metastatic breast, prostate and colorectal cancers using a microfluidic chip which is processed by using an automated staining and scanning system from sample preparation to image processing. The Celsee system allowed for the detection of CTCs with apparent high sensitivity and specificity (94% sensitivity and 100% specificity). Moreover, the system facilitated rapid capture of CTCs from blood samples and also allowed for downstream characterization of the captured cells by immunohistochemistry, DNA and mRNA fluorescence in-situ hybridization (FISH). In a subset of patients with prostate cancer we compared the technology with a FDA-approved CTC device, CellSearch and found a higher degree of sensitivity with the Celsee instrument. In conclusion, the integrated Celsee system represents a promising CTC technology for enumeration and molecular characterization.     

Effects of gonadal steroids on agonistic behavior of female Peromyscus leucopus

The role of gonadal hormones in modifying agonistic behavior of female P. leucopus was examined by means of ovariectomy and treatment with estradiol benzoate (EB), progesterone (P), or testosterone propionate (TP). Aggression was lower in diestrous females than in proestrous females, and was eliminated by ovariectomy. Submissive behavior increased following ovariectomy; surgery had no effect on investigative behavior. Administration of EB had no effect on aggressive or submissive behavior, but higher dosages caused an increase in investigative and sexual behavior. Higher dosages of P increased aggression; P had no effect on submissive or investigative behavior. An increase in aggression also resulted from administration of high levels of TP. TP also caused an increase in investigative behavior, and had no effect on submissive behavior. These results may be due to direct effects of the administered hormones on behavior or to indirect effects such as a stimulation of prolactin secretion or alteration of adrenal function.     

Fluidized bed adsorption for whole broth extraction.

Fluidized bed adsorption using a high-density synthetic resin has proven to be an invaluable technique for separating novel compounds from unfiltered fermentation broths during the very early stages of fermentation development, where product concentrations are typically in the parts per million range. Previous initial downstream processing strategies consisted of cell separation from whole broth or direct extraction with water-immiscible solvents, both of which resulted in lengthy time cycles, conflicts with existing operations requiring the use of high-cost centrifugal separators, and environmental/solvent recovery concerns. Laboratory and subsequent pilot plant process development work along with concomitant improvements in yield, quality, and time cycles are presented for one of several fluidized bed processes piloted in Merck's Natural Product Isolation facility.     

Multiple Group I Introns in the Small-Subunit rDNA of Botryosphaeria dothidea: Implication for Intraspecific Genetic Diversity

Botryosphaeria dothidea is a widespread and economically important pathogen on various fruit trees, and it often causes die-back and canker on limbs and fruit rot. In characterizing intraspecies genetic variation within this fungus, group I introns, rich in rDNA of fungi, may provide a productive region for exploration. In this research, we analysed complete small subunit (SSU) ribosomal DNA (rDNA) sequences of 37 B. dothidea strains, and found four insertions, designated Bdo.S943, Bdo.S1199-A, Bdo.S1199-B and Bdo.S1506, at three positions. Sequence analysis and structure prediction revealed that both Bdo.S943 and Bdo.S1506 belonged to subgroup IC1 of group I introns, whereas Bdo.S1199-A and Bdo.S1199-B corresponded to group IE introns. Moreover, Bdo.S1199-A was found to host an open reading frame (ORF) for encoding the homing endonuclease (HE), whereas Bdo.S1199-B, an evolutionary descendant of Bdo.S1199-A, included a degenerate HE. The above four introns were novel, and were the first group I introns observed and characterized in this species. Differential distribution of these introns revealed that all strains could be separated into four genotypes. Genotype III (no intron) and genotype IV (Bdo.S1199-B) were each found in only one strain, whereas genotype I (Bdo.S1199-A) and genotype II (Bdo.S943 and Bdo.S1506) occurred in 95% of the strains. There is a correlation between B. dothidea genotypes and hosts or geographic locations. Thus, these newly discovered group I introns can help to advance understanding of genetic differentiation within B. dothidea.     

A blooming interest in the hydraulic traits of flowers

This article comments on : Water relations of Calycanthus flowers: Hydraulic conductance, capacitance, and embolism resistance     

MITOCHONDRIAL DNA PHYLOGENIES FOR THE DROSOPHILA OBSCURA GROUP

Species belonging to the obscura group of the genus Drosophila have long held a central position in evolutionary studies, especially in experimental population genetics. Despite the considerable amount of accumulated knowledge, many of the phylogenetic relationships of the species in the group remain unclear. Here we present DNA sequence data for the mitochondrial gene cytochrome oxidase I (COI) for 13 species native to both the Old and New Worlds. We combine these data with seven other mitochondrial gene sequences from previous studies, for a total of over 3 kb per species. Strongly supported conclusions include: (1) the two North American subgroups, pseudoobscura and affinis, are each monophyletic; and (2) among Eurasian species two unambiguous clades are identified, one containing D. tristis, D. ambigua, and D. obscura and the other containing D. guanche, D. subobscura, and D. madeirensis. Constructing firm hypotheses connecting these four major clades is problematic with all datasets. Major ambiguities are the number of invasions giving rise to the North American obscura species and the relationships among the Eurasian species. The inadequacy of the mtDNA data to resolve these ambiguities does not reside in lack of changes; the transversions-only parsimony tree has 283 informative characters. Rather, the problems are likely intrinsic to the history of the group: while radiating in temperate Eurasia, North America was colonized once or twice, followed by one or two radiations in the New World.