Loss of the PGE1 requirement for MDCK cell growth associated with a defect in cyclic AMP phosphodiesterase

Prostaglandin E₁(PGE₁), one of the components in the hormone-supplemented, serum-free medium for Madin Darby Canine Kidney (MDCK) cells (Medium K-1), is required for both long-term growth and for dome formation. Variant cells have been isolated from MDCK populations, which lack the PGE₁, requirement for long-term growth in Medium K-1. These variants will be useful in identifying the molecular events initiated by PGE₁ which are necessary for the growth response to be observed. The growth and functional properties of five independently isolated PGE₁ independent clones have been examined. Normal MDCK cells grew at an equivalent rate in Medium K-1 and in serum-supplemented medium; the growth rate was lower in Medium K-1 lacking PGE₁. In contrast, PGE₁ independent clone 1 grew at an equivalent rate in Medium K-1 minus PGE₁, and in serum-supplemented medium. When PGE₁ was added to K-1 minus PGE₁, less growth of PGE₁ independent clone 1 was observed. A similar observation was made with one other PGE₁ independent clone which was studied. A hormone deletion study indicated that PGE₁ independent clone 1 still retained growth responses to the other four supplements in Medium K-1 (insulin, transferrin, T₃, and hydrocortisone). The molecular alterations associated with loss of the PGE₁ requirement for long-term growth were examined. At confluency, all of the PGE₁ independent clones studied had higher intracellular cyclic AMP levels following PGE₁ treatment, as compared with normal MDCK cells. The increased cyclic AMP levels in the variant cells could result from a number of different types of defects, including reduced cyclic adenylic acid (cyclic AMP) efflux, an increased affinity of PGE₂ for the PGE₁ receptor, or a defect in cyclic AMP metabolism. However, in all of the variant clones studied a decreased rate of cyclic AMP degradation by cyclic AMP phosphodiesterase was observed. Thus, the increased cyclic AMP levels in the PGE₁ independent variants may result from alterations which affect cyclic AMP metabolism. The effect of PGE₁ on dome formation by the variant cells was also examined. The frequency of dome formation by PGE₁ independent clone 1 was enhanced in a dosage-dependent manner, like normal MDCK cells. This observation suggests that PGE₁ affects MDCK cell growth and dome formation by different mechanisms.     

Licht- und elektronenmikroskopische untersuchungen zur haftborstenentwicklung bei Tarentola m. mauritanica L. (Reptilia,Gekkonidae)

Zusammenfassung Kurz nach einer Hdutung wird bei Tarentola m. m. bereits die übemächste Epidermisgeneration — und somit auch die der Haftborsten —angelegt. Das geschieht vornehmlich in der Oz- (Oberhäutchenzellen-) und in der Hs-Schicht (clear layer). Zunächst entstehen die Aufspaltungen der Haftborstenenden, indem Keratinfilamentbündel nach einem bestimmten System von den Oz-Zellen aus in die Hs-Zellen einwachsen. Auf these Weise fungieren die Zellen der Hs-Schicht als Matrix der Haftborsten. Nach Abschluß dieses Prozesses werden die eigentlichen Haftborsten gebildet unter gleichzeitigem Auseinanderrücken der Hs- und Oz-Schichten. Die Hs-Schicht behdlt ihre Matrizen-Funktion bis zur anschließenden Häutung bei.

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Light and electron microscope studies of developing setae of Tarentola m. mauritanica (Rept., Gekkonidae)

Summary In Tarentola m. mauritanica the next epidermis generation but one and therefore the adhesive setae of the generation after this begin to develop shortly after a skin has been shed. This development takes place principally in the horny layer (Oz) and the clear layer. First bundles of keratin filaments radiate from the horny layer into the clear layer, thus giving rise to the split distal parts of the adhesive bristles. Thus the cells in the clear layer act as a matrix for the setae. When this stage is complete the formation of the setae proper begins, while the horny layer and the clear layer become separated from each other. The clear layer retains its function as matrix for the setae until the next time a skin is shed.

     

Cell retention-chemostat studies of hybridoma cells-analysis of hybridoma growth and metabolism in continuous suspension culture in serum-free medium

The steady-state metabolic parameters for a hybridoma cell line have been determined in continuous suspension-perfusion culture over a wide range of perfusion rates and cell bleed rates. Significant increases in viable cell concentrations and volumetric productivities were achieved at high perfusion rates and low cell bleed rates. At the low growth rates examined in this study, cellular metabolism shifted to become more oxidative, and as a result, the fraction of consumed substrate converted to inhibitory metabolic by-products was reduced. Specific antibody productivity was found to be non-growth associated. (c) 1993 John Wiley & Sons, Inc.     

Temperature Interactions with Growth Regulators and Endogenous Gibberellin-like Activity during Seedstalk Elongation in Carrots

Stecklings (roots) of three cultivars of carrots (Daucus carota L.) were vernalized 10 weeks at 5 C and subsequently grown at each of three greenhouse night/day temperature regimes: high (27/32 C), medium (21/27 C), and low (15/21 C). Floral differentiation occurred first in the easy bolting cv. Scarlet Nantes, intermediate in cv. Danvers 126, and last in cv. Royal Chantenay. Stem elongation arising from the subapical meristematic region always preceded floral differentiation. Extractable gibberellin-like activity in carrot stem apices increased from harvest during the 10-week vernalization period, then remained constant even though floral differentiation and stem elongation occurred during an additional 20-week cold storage period. Low temperature had both an inductive and a direct effect on reproductive development depending on length of low temperature exposure.     

A locus for familial hypertrophic cardiomyopathy is closely linked to the cardiac myosin heavy chain genes, CRI-L436, and CRI-L329 on chromosome 14 at q11-q12

We report that a gene responsible for familial hypertrophic cardiomyopathy (HC) is closely linked to the cardiac alpha and beta myosin heavy chain (MHC) genes on chromosome 14q11. We have recently shown that probe CRI-L436, derived from the anonymous DNA locus D14S26, detects a polymorphic restriction fragment that segregates with familial HC in affected members of a large Canadian family. Using chromosomal in situ hybridization, we have mapped CRI-L436 to chromosome 14 at q11-q12. Because the cardiac MHC genes also map to this chromosomal band, we have determined the genetic distances between the cardiac beta MHC gene, D14S26, and the familial HC locus. Data presented here show that these three loci are linked within 5 centimorgans on chromosome 14 at q11-q12. The possibility that defects in either the cardiac alpha or beta MHC genes are responsible for familial HC is discussed.     

Oxidation of methionine by X2.- in aqueous solution and characterization of some S therefore X three-electron bonded intermediates. A pulse radiolysis study

The primary steps of the oxidation of methionine, Met, by X2.- (X = Cl; Br, I, SCN) have been investigated using pulse radiolysis techniques. In principle, the mechanism follows the same pattern which has been established for the OH radical induced oxidation. It is characterized by a primary attack at the sulphur atom and the formation of sulphur-centred radical cations S+. and S therefore (+) S as key intermediates. At pH greater than pKa of the carboxyl group these can then oxidize the amino function intramolecularly, which subsequently leads to irreversible decarboxylation. An additional important intermediate is a S therefore X radical with a three-electron bond between sulphur and halide. This radical is linked to the OH . radical induced mechanism through the equilibrium S therefore X + Met in equilibrium with S therefore (+) S + X-, and in addition exists in the equilibria X2.- + Met in equilibrium with S therefore X + X-, S therefore X in equilibrium with S+. + X- and S therefore X in equilibrium with Met + X.. The S therefore X- species absorb at 410, 400, and 390 nm for X = I, Br, and Cl, respectively. Absolute rate constants have been measured for the reactions S therefore (+) S + I- (k = 1.0 x 10(10) mol-1 ls-1, pH 1.4), Br2.- + Met (k = 2.5 x 10(9), 1.7 x 10(9), and 2.0 x 10(9) mol-1 ls-1 at pH 1, 5, and 11, respectively) and Cl2.- + Met (k = 3.9 x 10(9) mol-1 ls-1, pH 1). Methionine is also oxidized by (SCN)2.- whereas any significant oxidation by I2.- is not indicated. N-acetylmethionine, a model compound for a sulphur-containing peptide, and some other methionine derivatives are oxidized by X2.- in the same way, that is, through electrophilic addition at the sulphur function. The results require reinterpretation of some data published in the literature and are discussed in view of a 'selective free radical attack'.     

A modified MOPP regimen in the treatment of Hodgkin's disease stage III B and IV (author's transl)

In a retrospective study 80 patients with Hodgkin's disease of stage III B (n = 32) and IV (n = 48) were investigated, who had been treated with a modified MOPP regimen. 28 patients (35%) were previously untreated. A completed remission was reached in 51 patients, a partial remission in 16, and 13 patients failed to respond. 16 patients had died in the observation period. Complete remissions were twice as frequent with 90% in stage III as compared with 45% in stage IV. The group of patients surviving 4 years was 92% in stage III and 62% in stage IV.     

Fibroblast growth factor-9 expression in airway epithelial cells amplifies the type I interferon response and alters influenza A virus pathogenesis

Influenza A virus (IAV) preferentially infects conducting airway and alveolar epithelial cells in the lung. The outcome of these infections is impacted by the host response, including the production of various cytokines, chemokines, and growth factors. Fibroblast growth factor-9 (FGF9) is required for lung development, can display antiviral activity in vitro, and is upregulated in asymptomatic patients during early IAV infection. We therefore hypothesized that FGF9 would protect the lungs from respiratory virus infection and evaluated IAV pathogenesis in mice that overexpress FGF9 in club cells in the conducting airway epithelium (FGF9-OE mice). However, we found that FGF9-OE mice were highly susceptible to IAV and Sendai virus infection compared to control mice. FGF9-OE mice displayed elevated and persistent viral loads, increased expression of cytokines and chemokines, and increased numbers of infiltrating immune cells as early as 1 day post-infection (dpi). Gene expression analysis showed an elevated type I interferon (IFN) signature in the conducting airway epithelium and analysis of IAV tropism uncovered a dramatic shift in infection from the conducting airway epithelium to the alveolar epithelium in FGF9-OE lungs. These results demonstrate that FGF9 signaling primes the conducting airway epithelium to rapidly induce a localized IFN and proinflammatory cytokine response during viral infection. Although this response protects the airway epithelial cells from IAV infection, it allows for early and enhanced infection of the alveolar epithelium, ultimately leading to increased morbidity and mortality. Our study illuminates a novel role for FGF9 in regulating respiratory virus infection and pathogenesis.     

Analysis of spacing in a periodic pattern

Colonies of hydroids exhibit periodic biological patterns. Polyps form on stolons at fixed distances, obeying distinct rules. The spacing mechanism is based on inhibition emanating from existing polyps, predominantly from the head of the polyp. Removal of polyps from young colonies reduces the distance between initiating polyps and newly formed polyps to 50% of the normal values. Head removal suffices to obtain an almost identical reduction. Polyp enlargement which increases the distance between the inhibition-emitting head and the stolon tissue reduces the intrastolonal range of inhibition. In the stolon tissue, decrease of inhibitory activity occurs. An increase in the stolon/polyp ratio of a colony reduces bud distances. The decay is, in part, due to loss of inhibitory activity into the external medium: if colonies are incubated in conditioned culture medium derived from crowded colonies having normally large interpolyp distances, bud distances increase in test colonies. The effectiveness of transfer of inhibitory activity from tissue into the medium depends on culture conditions. If convection is increased by agitation of the culture medium, the distances between polyp and bud decreases; viscosity enhancement of the culture medium reduces convection and bud distances become larger. This effect is compensated for by additional agitation of the viscosity enhanced culture medium. Our results support the idea that a lateral inhibition mechanism controls polyp spacing in the stolon and that inhibition is based on diffusible inhibitory compounds.