p53 Down Regulates PDGF-Induced Formation of Circular Dorsal Ruffles in Rat Aortic Smooth Muscle Cells

The tumor suppressor, p53, negatively regulates cell migration and invasion in addition to its role in apoptosis, cell cycle regulation and senescence. Here, we study the roles of p53 in PDGF-induced circular dorsal ruffle (CDR) formation in rat aortic smooth muscle (RASM) cells. In primary and immortalized RASM cells, up-regulation of p53 expression or increase in activity with doxorubicin inhibits CDR formation. In contrast, shRNA-knockdown of p53 or inhibition of its activity with pifithrin α promotes CDR formation. p53 acts by up-regulating PTEN expression, which antagonizes Rac and Cdc42 activation. Both lipid and protein phosphatase activities of PTEN are required for maximal suppression of CDR, but the lipid activity clearly plays the dominant role. N-WASP, the downstream effector of Cdc42, is the major positive contributor to CDR formation in RASM, and is an indirect target of p53. The Rac effector, WAVE2, appears to also play a minor role, while WAVE1 has no significant effect in CDR formation. In sum, we propose that p53 suppresses PDGF-induced CDR formation in RASM cells by upregulating PTEN leading mainly to the inhibition of the Cdc42-N-WASP pathway.     

Comparison of endogenous murine leukemia virus proviral organization and RNA expression in 3-methylcholanthrene-induced and spontaneous thymic lymphomas in RF and AKR mice.

3-Methylcholanthrene-induced T-cell thymic lymphomas in RF mice were examined for involvement of murine leukemia virus (MuLV)-related sequences in leukemogenesis. Both the expression of MuLV-related RNA species and the organization of endogenous MuLV proviral DNA were analyzed. Of 27 primary tumors examined, only 5 exhibited elevated MuLV-related RNA species homologous to xenotropic specific env DNA. None of these RNA species hybridized with ecotropic p15E DNA sequences. Only two of these five tumors contained MuLV-like RNA species that hybridized with ecotropic MuLV long terminal repeat sequences, despite the probe's ability to detect both ecotropic MuLV and mink cell focus-inducing viral RNA. No muLV resembling mink cell focus-inducing virus whose expression could be correlated with lymphomagenesis was detected in either preleukemic thymocytes, primary 3-methylcholanthrene-induced thymic tumors, tumors passaged in vivo, or cell lines derived from tumors. Restriction endonuclease analysis of DNA from both primary tumors and cell lines failed to reveal either proviral DNA with recombinant env genes or rearrangement of endogenous MuLV proviruses. Therefore, chemically induced lymphomagenesis in RF mice appears different from the spontaneous lymphomagenic process in AKR mice with respect to the involvement of endogenous MuLV sequences.     

Development of a large-scale continuous substrate feed process for the biotransformation of simvastatin by Nocardia s.p

This article describes a process for microbial hydroxylation of simvastatin by a Nocardia sp. Simvastatin (Zocor) belongs to the family of HMGCoA reductase inhibitors used as cholesterol-lowering drugs. Studies at 14 L scale showed that high substrate (simvastatin) concentrations inhibited product formation; consequently, continuous slow feeding of the substrate was introduced to maintain low residual simvastatin concentrations. Dissolved oxygen levels above 50% air saturation were desirable for the biotransformation. The process was scaled up to 19,000-L fermentors using an on-line filter sterilization system for substrate feeding. The feed rate was regulated by off-line high-pressure liquid chromatography (HPLC) assays to keep the substrate concentration below 20 mg/L. Intermittent addition of nutrients helped to boost the bioconversion rate to give final titers of 400 mg/L 6-beta-hydroxymethyl simvastatin. Enrichment of the nutrient medium led to bioconversion titers of 800 mg/L 6-beta-hydroxymethyl simvastatin. Bioconversion efficiencies (desired product/substrate) of 22-25% with a ratio of desired product/side products of 0.7 were obtained by this process.     

Lewis cell studies to determine reactor design data for two-liquid-phase bacterial and enzymic reactions

Substrate transfer rates from organic to aqueous phases were measured in the presence and absence of biocatalyst in the reaction medium, using modified Lewis cells. These measurements, in combination with intrinsic aqueous phase biocatalytic reaction kinetics, were used to confirm that benzyl acetate hydrolysis by pig liver esterase and toluene oxidation by a strain of Pseudomonas putida occur uniformly throughout the bulk of the aqueous phase. Such data may be used to provide a basis for two-liquid-phase biocatalytic reactor design.     

Immobilization of Burkholderia cepacia in polyurethane-based foams: embedding efficiency and effect on bacterial activity

Immobilization of the trichloroethylene-degrading bacterium Burkholderia cepacia was evaluated using hydrophilic polyurethane foam. The influence of several foam formulation parameters upon cell retention was examined. Surfactant type was a major determinant of retention; a lecithin-based compound retained more cells than pluronic- or silicone-based surfactants. Excessive amounts of surfactant led to increased washout of bacteria. Increasing the biomass concentration in the foam from 4.8 to 10.5% dry weight per wet weight of foam resulted in fewer cells being washed out. Embedding at reduced temperature did not significantly affect retention, while the use of a silane binding agent gave inconsistent results. The optimal formulation retained all but 0.2% of total embedded cells during passage of 2 L of water through columns containing 2 g of foam. All foam formulations tested reduced the culturability of embedded cells by several orders of magnitude, but O₂ consumption and CO₂ evolution rates of embedded cells were never less than 50% of those of free cells. Nutrient amendments stimulated an increase in cell volume and ribosomal activity in immobilized cells as indicated by hybridization studies using fluorescently labeled ribosomal probes. These results indicate that, although immobilized cells were mostly nonculturable, they were metabolically active and thus could be used for biodegradation of toxic compounds. Received 23 December 1996/ Accepted in revised form 13 March 1997     

Respiratory transfer impedance between 8and 384Hz in guinea pigs before and after bronchial challenge

Sobh, Jamil F., Craig M. Lilly, Jeffrey M. Drazen, andAndrew C. Jackson. Respiratory transfer impedance between 8 and384 Hz in guinea pigs before and after bronchial challenge. J. Appl. Physiol. 82(1): 172-181, 1997.We report a forced oscillatory technique for noninvasivelymeasuring respiratory transfer impedance (Ztr) between 8 and 384 Hz inguinea pigs. This technique uses a device consisting of two chambers:one surrounding the animal's head that is used as a plethysmograph tomeasured flow through the airway opening and the other that surroundsthe animal's body and is used to apply pressure oscillations to thebody surface. Ztr was measured in spontaneously breathing awake guineapigs and while the animals were anesthetized in normal andmethacholine-challenged conditions. An eight-element model consistingof an airway compartment separated from a tissue compartment by a shuntgas compression compartment was fit to the data. Anesthesia increasedcentral and peripheral airway resistance and bronchial airway wallcompliance by 13, 31, and 44%, respectively, whereas it decreasedtissue compliance by 37%. Compared with the unanesthetized condition, the methacholine challenge (20 µg/kg) resulted in an increase incentral and peripheral airway resistance (69 and 319%, respectively) and a decrease in bronchial airway wall and tissue compliance (37 and79%, respectively). This technique is capable of measuring Ztr inanesthetized and awake guinea pigs. Analysis of these data with thiseight-element model provides reasonable estimates of airway and tissueparameters.

     

Trends in Food Habits and Their Relation to Socioeconomic Status among Nordic Adolescents 2001/2002-2009/2010

Background

In the Nordic countries, substantial policy and intervention efforts have been made to increase adolescents'' consumption of fruit and vegetables and to reduce their intake of sweets and soft drinks. Some initiatives have been formulated in a Nordic collaboration and implemented at national level. In recent years, social inequalities in food habits have been attracted particular governmental interest and several initiatives addressing the socioeconomic gradient in food habits have been highlighted. However, few internationally published studies have evaluated how trends in adolescents'' food habits develop in the context of Nordic nutrition policy, or have compared differences between the Nordic countries.

Methods

The study was based on Danish, Finnish, Norwegian and Swedish cross-sectional data from the international Health Behaviour in School-Aged Children (HBSC) study, collected via three nationally representative and comparable questionnaire surveys in 2001/2002, 2005/2006 and 2009/2010. Food habits were identified by students'' consumption of fruit, vegetables, sweets and sugar sweetened soft drink. Socioeconomic status (SES) was measured with the Family Affluence Scale (FAS). Multilevel logistic regression was used to analyze the data.

Results

Trends in fruit consumption developed differently across countries, characterized by an increase in Denmark and Norway and more stable trends in Sweden and Finland. Vegetable consumption increased particularly in Denmark and to a lesser extent in Norway, whereas Sweden and Finland displayed stable trends. Decreased trends were observed for sweet and soft drink consumption and were similar in Norway, Sweden and Finland. Sweet consumption decreased across all survey years, whereas soft drink consumption decreased between 2001/2002–2005/2006 and was stable thereafter. Denmark displayed an increase between 2001/2002–2005/2006 followed by a similar decrease between 2005/2006–2009/2010 for both sweet and soft drink consumption. Socioeconomic inequalities in fruit and vegetable consumption were observed in all countries, with no cross-country differences, and no changes over time. Small but not significant cross-country variation was identified for SES inequalities in sweet consumption. Reduced SES inequalities were observed in Sweden between 2005/2006 and 2009/2010. SES was not associated with soft drink consumption in this study population, with the exception of Denmark for the survey year 2009/2010.

Conclusion

Different trends resulted in increased country differences in food habits during the time of observations. In survey year 2009/2010, Danish students reported a higher intake of fruit and vegetable consumption than their counterparts in the other Nordic countries. Finnish students reported the lowest frequency of sweets and soft drink consumption. Despite the positive dietary trends documented in the present study, the majority of Nordic adolescents are far from meeting national dietary recommendations. Our findings underline the need for more comprehensive initiatives targeting young people''s food habits as well as a more deliberate and focused action to close gaps in social inequalities that affect food choices.     

Restriction-map variation associated with the G6PD polymorphism in natural populations of Drosophila melanogaster

Restriction-map variation was studied in 126 copies of the G6pd region in X chromosome lines of Drosophila melanogaster from North America, Europe, and Africa. Special attention was focused on the distribution of variation relative to the geographically variable polymorphism for two electrophoretic variants. Nucleotide heterozygosity as determined by eight six-cutter restriction enzymes for the 13-kb region is estimated, on the basis of the worldwide sample, to be 0.065%, which is the lowest value reported for any comparable region in the D. melanogaster genome. Significant linkage disequilibrium between electrophoretic alleles and restriction-site variation is observed for several sites. In contrast to published studies of other genetic regions, there are large insertions that reach significant frequencies and are found across considerable geographic distances. There is a clustering of this variation inside the first large intervening sequence of the G6PD gene.