Exon identity crisis: disease-causing mutations that disrupt the splicing code

Cis-acting RNA elements control the accurate expression of human multi-exon protein coding genes. Single nucleotide variants altering the fidelity of this regulatory code and, consequently, pre-mRNA splicing are expected to contribute to the etiology of numerous human diseases.     

Examining olfactory and visual cues governing host-specificity of a weed biological control candidate species to refine pre-release risk assessment

In weed biological control programs, pre-release host-specificity testing relies traditionally on no-choice and choice feeding, oviposition, and development tests. Rarely have they included detailed examination of behavioral responses to olfactory and visual cues of biological control candidates, although a better understanding of the mechanisms underlying host recognition may explain potential discrepancies between choice and no-choice tests, and/or between tests conducted in the lab versus field conditions. We investigated how the seed-feeding weevil, Mogulones borraginis, distinguishes its host plant, Cynoglossum officinale, from three native confamilial non-target species in North America. In behavioral bioassays, M. borraginis responded to olfactory and visual cues individually and, to an even greater extent, to both plant cue modalities when offered simultaneously. In tests with the combined cues, M. borraginis was attracted to C. officinale but responded with indifference or was repelled by non-target plants. In electrophysiological experiments, we identified that M. borraginis responded to ten volatile compounds and four wavelengths of lights from inflorescences of C. officinale. We propose that studies of responses to multimodal plant cues can advance our understanding of how biocontrol candidate species discriminate among host plants and closely related non-target species, thereby increasing the accuracy of environmental safety assessments pre-release.     

TGFbeta2 in corneal morphogenesis during mouse embryonic development.

To examine the roles of TGFbeta isoforms on corneal morphogenesis, the eyes of mice that lack TGFbetas were analyzed at different developmental stages for cell proliferation, migration and apoptosis, and for expression patterns of keratin 12, lumican, keratocan and collagen I. Among the three Tgfb(-/-) mice, only Tgfb2(-/-) mice have abnormal ocular morphogenesis characterized by thin corneal stroma, absence of corneal endothelium, fusion of cornea to lens (a Peters'-like anomaly phenotype), and accumulation of hyaline cells in vitreous. In Tgfb2(-/-) mice, fewer keratocytes were found in stroma that has a decreased accumulation of ECM; for example, lumican, keratocan and collagen I were greatly diminished. The absence of TGFbeta2 did not compromise cell proliferation, nor enhance apoptosis. The thinner stroma resulting from decreased ECM synthesis may account for the decreased cell number in the stroma of Tgfb2 null mice. Keratin 12 expression was not altered in Tgfb2(-/-) mice, implicating normal corneal type epithelial differentiation. Delayed appearance of macrophages in ocular tissues was observed in Tgfb2(-/-) mice. Malfunctioning macrophages may account for accumulation of cell mass in vitreous of Tgfb2 null mice.     

Isolation and Characterization of Desulfovibrio dechloracetivorans sp. nov., a Marine Dechlorinating Bacterium Growing by Coupling the Oxidation of Acetate to the Reductive Dechlorination of 2-Chlorophenol

Strain SF3, a gram-negative, anaerobic, motile, short curved rod that grows by coupling the reductive dechlorination of 2-chlorophenol (2-CP) to the oxidation of acetate, was isolated from San Francisco Bay sediment. Strain SF3 grew at concentrations of NaCl ranging from 0.16 to 2.5%, but concentrations of KCl above 0.32% inhibited growth. The isolate used acetate, fumarate, lactate, propionate, pyruvate, alanine, and ethanol as electron donors for growth coupled to reductive dechlorination. Among the halogenated aromatic compounds tested, only the ortho position of chlorophenols was reductively dechlorinated, and additional chlorines at other positions blocked ortho dechlorination. Sulfate, sulfite, thiosulfate, and nitrate were also used as electron acceptors for growth. The optimal temperature for growth was 30°C, and no growth or dechlorination activity was observed at 37°C. Growth by reductive dechlorination was revealed by a growth yield of about 1 g of protein per mol of 2-CP dechlorinated, and about 2.7 g of protein per mole of 2,6-dichlorophenol dechlorinated. The physiological features and 16S ribosomal DNA sequence suggest that the organism is a novel species of the genus Desulfovibrio and which we have designated Desulfovibrio dechloracetivorans. The unusual physiological feature of this strain is that it uses acetate as an electron donor and carbon source for growth with 2-CP but not with sulfate.     

Semi-automated imaging system to quantitate Her-2/neu membrane receptor immunoreactivity in human breast cancer.

BACKGROUND: Immunocytochemical methods for quantitating Her-2/neu immunoreactivity rest on subjective semi-quantitative interpretations with resulting interobserver, intraobserver, and fatigue variability. METHODS: To standardize and quantitate measurements of Her-2/neu immunoreactivity, we created epithelial-recognition and specific membrane-recognition algorithms, which could image breast cancer cells against a background of stroma, compartmentalize the cancer cell into nucleus, cytoplasm and membrane, and quantitate the degree of Her-2/neu membrane immunoreactivity based on both gray scale intensity and RGB colorimetric determinations. Image acquisition utilized either scanner or microscope with attached camera with a resolution of 20 pixels/10 microm. Areas of 150 whole slides were screened and the regions of interest manually selected for image processing. Three hundred TMA cores were directly processed. Images were acquired by jpg conversion of svs virtual slides or direct jpg photomicrograph capture. Images were then assessed for quality and processed. RESULTS: The digital algorithms successfully created a semi-automated imaging system whose algorithm-based ordinal values for Her-2/neu both strongly correlated with the subjective measurements (intraclass correlation: 0.84; 95% confidence interval: 0.79-0.89) yet exhibited no run variability. In addition, the algorithms generated immunocytochemical measurements of Her-2/neu on an expanded continuous scale, which more reliably distinguished true Her-2/neu positivity from true Her-2/neu negativity (determined by FISH) than subjective or algorithmic ordinal scale measurements. Furthermore, the continuous scale measurements could better resolve different levels of Her-2/neu overexpression than either subjective or algorithmic ordinal interpretation. Other semi-automated analysis systems have been used to measure Her-2/neu and other cellular immunoreactivities, but these either have required proprietary hardware or have been based on luminosity differences alone. In contrast, our algorithms are independent of proprietary hardware and are based on not just luminosity but also many other imaging properties including epithelial recognition and membrane morphology. CONCLUSION: These features provide a more accurate, versatile, and robust imaging analysis platform.     

THE FINE STRUCTURE OF NEURONS

1. Thin sections of representative neurons from intramural, sympathetic and dorsal root ganglia, medulla oblongata, and cerebellar cortex were studied with the aid of the electron microscope. 2. The Nissl substance of these neurons consists of masses of endoplasmic reticulum showing various degrees of orientation; upon and between the cisternae, tubules, and vesicles of the reticulum lie clusters of punctate granules, 10 to 30 mµ in diameter. 3. A second system of membranes can be distinguished from the endoplasmic reticulum of the Nissl bodies by shallower and more tightly packed cisternae and by absence of granules. Intermediate forms between the two membranous systems have been found. 4. The cytoplasm between Nissl bodies contains numerous mitochondria, rounded lipid inclusions, and fine filaments.