Contraction of isolated airway smooth muscle by synthetic leukotrienes C4 and D4

The pharmacology of leukotrienes (LT) C4 and D4 in isolated airway smooth muscle was investigated. In rat trachea, neither LTC4 or D4 elicited a response. In contrast, LTC4 was a potent contractile agonist in guinea-pig trachea, bronchus and parenchymal lung strip. Similar effects were obtained with LTD4 in trachea and parenchyma. In trachea and bronchus, the concentration-response curve to LTC4 was biphasic: indomethacin converted the biphasic response curve to a simple sigmoidal shape and enhanced the maximum contractile response. The SRS-A antagonist FPL 55712 antagonized the effect of LTD4 in both trachea and parenchyma. As regards LTC4-induced contraction of trachea and bronchus, FPL 55712, depending on concentration, either antagonized, or antagonized and enhanced the maximum contractile response. The enhancement of the maximum contractile response by FPL 55712 was not apparent when indomethacin was present. FPL 55712 failed to antagonize the effect of LTC4 in parenchyma.     

Growth of Certain Aquatic Oomycetes on Amino Acids II. Apodachlya, Aphanomyces, and Pythium

Four aquatic fungi —Apodachlya brachynema and A. minima (Leptomitales), Aphanomyces laevis (Saprolegniales), and Pythium ultimum (Peronosporales) —were tested for growth in synthetic media containing one of a variety of carbon sources. Apodachlya brachynema readily utilized five amino acids — alanine, glutamate, aspartate, proline and leucine — as well as glucose and acetate. Growth on sucrose as a carbon source was slight. Apodachlya minima differed from A. brachynema in that it could not utilize proline and leucine. Aphanomyces laevis grew well on only three of the substrates tested — glucose, alanine and glutamate. Pythium ultimum utilized glucose, sucrose, maltose, cellobiose, alanine, glutamate, aspartate, proline, asparagine, ornithine, and serine, but not eight other amino acids. All of these fungi hydrolyzed gelatin. Radioactively labeled carbon dioxide was released during incubation of Aphanomyces laevis in media containing labeled leucine, proline, or phenylalanine. These data provide evidence of some catabolism of the three substrates although none of these substrates can support the growth of Aphanomyces laevis as a sole source of carbon and nitrogen.     

Spiropiperidine CCR5 antagonists

A novel series of CCR5 antagonists has been identified, utilizing leads from high-throughput screening which were further modified based on insights from competitor molecules. Lead optimization was pursued by balancing opposing trends of metabolic stability and potency. Selective and potent analogs with good pharmacokinetic properties were successfully developed.     

Wnt signaling controls the stem cell-like asymmetric division of the epithelial seam cells during C. elegans larval development

Metazoan stem cells repopulate tissues during adult life by dividing asymmetrically to generate another stem cell and a cell that terminally differentiates. Wnt signaling regulates the division pattern of stem cells in flies and vertebrates. While the short-lived nematode C. elegans has no adult somatic stem cells, the lateral epithelial seam cells divide in a stem cell-like manner in each larval stage, usually generating a posterior daughter that retains the seam cell fate and an anterior daughter that terminally differentiates. We show that while wild-type adult animals have 16 seam cells per side, animals with reduced function of the TCF homolog POP-1 have as many as 67 seam cells, and animals with reduced function of the β-catenins SYS-1 and WRM-1 have as few as three. Analysis of seam cell division patterns showed alterations in their stem cell-like divisions in the L2-L4 stages: reduced Wnt signaling caused both daughters to adopt non-seam fates, while activated Wnt signaling caused both daughters to adopt the seam fate. Therefore, our results indicate that Wnt signaling globally regulates the asymmetric, stem cell-like division of most or all somatic seam cells during C. elegans larval development, and that Wnt pathway regulation of stem cell-like behavior is conserved in nematodes.     

Can zoosporic true fungi grow or survive in extreme or stressful environments?

Zoosporic true fungi are thought to be ubiquitous in many ecosystems, especially in cool, moist soils and freshwater habitats which are rich in organic matter. However, some of the habitats where these fungi are found may periodically experience extreme conditions, such as soils in extremely dry, hot and cold climates, acidic and alkaline soils, polluted rivers, anaerobic soil and water, saline soil and water, periglacial soils, oligotrophic soils, tree canopies and hydrothermal vents. It is clear that many ecotypes of zoosporic true fungi have indeed adapted to extreme or stressful environmental conditions. This conclusion is supported by studies in both the field and in the laboratory. Therefore, in our opinion, at least some true zoosporic fungi can be considered to be extremophiles.     

Immunohistochemical detection of the beta4 integrin subunit in pancreatic adenocarcinoma.

The expression of the beta4 integrin subunit protein in pancreatic cancer was investigated using routine immunohistochemical methods on paraffin-embedded archival material. Forty-eight cases of pancreatic ductal adenocarcinoma were immunostained with a monoclonal antibody to the beta4 integrin subunit, and the extent of staining was compared with that seen in non-cancerous pancreatic tissues, including 15 separate cases of chronic pancreatitis and 6 sections from normal pancreas. We found that the beta4 integrin subunit protein was overexpressed in the majority of pancreatic carcinoma cases tested, whereas chronic pancreatitis and normal pancreas did not display substantial levels of expression.     

A mutation in serca underlies motility dysfunction in accordion zebrafish

Zebrafish acquire the ability for fast swimming early in development. The motility mutant accordion (acc) undergoes exaggerated and prolonged contractions on both sides of the body, interfering with the acquisition of patterned swimming responses. Our whole cell recordings from muscle indicate that the defect is not manifested in neuromuscular transmission. However, imaging of skeletal muscle of larval acc reveals greatly prolonged calcium transients and associated contractions in response to depolarization. Positional cloning of acc identified a serca mutation as the cause of the acc phenotype. SERCA is a sarcoplasmic reticulum transmembrane protein in skeletal muscle that mediates calcium re-uptake from the myoplasm. The mutation in SERCA, a serine to phenylalanine substitution, is likely to result in compromised protein function that accounts for the observed phenotype. Indeed, direct evidence that mutant SERCA causes the motility dysfunction was provided by the finding that wild type fish injected with an antisense morpholino directed against serca, exhibited accordion-like contractions and impaired swimming. We conclude that the motility dysfunction in embryonic and larval accordion zebrafish stems directly from defective calcium transport in skeletal muscle rather than defective CNS drive.