Influence of Hydrocortisone on Chick Embryo Retina Development

Treatment of chick embryos in ovo with hydrocortisone-21-phosphate (a single dose of 150 micrograms) caused a marked reduction of retinal thymidine kinase activity 24 h later. The inhibitory effect was highest (65-70%) in 8-10-day-old embryos and declined with age, disappearing after day 15. It was accompanied by a reduction in thickness of the retinal layers. Adrenocorticotropic hormone (ACTH) treatment (10 micrograms daily for 2 days) also produced an age-dependent inhibitory effect on retinal thymidine kinase, whereas treatment with a single dose of 200 micrograms of metopirone, a compound that prevents the 11 beta-hydroxylation of steroid molecules in the adrenal glands, impeded the decrease in thymidine kinase activity that normally occurs in chick embryo retina after day 9 of development. In addition, metopirone prevented the inhibition exerted by ACTH on thymidine kinase activity but had no effect on the action of hydrocortisone.     

Fermentation procedure of a crude oil in continuous culture on seawater

Summary The crude oil was degraded (80%) in continuous culturing and non sterile conditions by a mixed bacteria community. The fermentation process relies on a step of pre-emulsification of the substrate before it is introduced into the reactor. The emulsification indispensable for degrading crude oil is performed by the mixed bacteria community during its growth on hydrocarbons. On the other hand, the use of an ultrafiltration device allows the obtention of high cell concentrations (7.6 g·l^-1) and high degradation rates.     

Influenza virus hemagglutinin expression is polarized in cells infected with recombinant SV40 viruses carrying cloned hemagglutinin DNA

Primary cell cultures of African Green monkey kidney (AGMK) contain polarized epithelial cells in which influenza virus matures predominantly at the apical surfaces above tight junctions. Influenza virus glycoproteins were found to be localized at the same membrane domain from which the virus budded. When polarized primary AGMK cells were infected with recombinant SV40 viruses containing DNA coding for either an influenza virus H1 or H2 subtype hemagglutinin (HA), the HA proteins were preferentially expressed at the apical surface in a manner identical to that observed in influenza virus-infected cells. Thus, cellular mechanisms for sorting membrane glycoproteins recognize some structural feature of the HA glycoprotein itself, and other viral proteins are not necessary for this process.     

Abrupt modifications of phospholipid bilayer properties at critical cholesterol concentrations.

The fluorescence generalized polarization (GP) of 2-dimethylamino-6-lauroylnaphthalene (Laurdan) reveals different effects of cholesterol on the phase behavior of phospholipid bilayers. Phospholipid vesicles composed of gel, liquid-crystalline, and coexisting domains of the two phases have been studied at temperatures from 1 to 65 degrees C, without cholesterol and with cholesterol concentrations of 3-50 mol %. Laurdan GP measurements show the general effect of cholesterol of increasing the molecular dynamics of the gel and of decreasing the molecular dynamics of the liquid-crystalline phase. In the liquid-crystalline phase, the increased order yields Laurdan GP values close to those obtained in the gel phase. At cholesterol concentrations > 15 mol % a phase transition cannot be detected. Using the wavelength dependence of the excitation and emission GP spectra we determine that differences between the two phospholipid phases cannot be detected. In particular, in vesicles composed of coexisting gel and liquid-crystalline phases the GP wavelength dependence characteristic of coexisting domains cannot be observed at cholesterol concentrations > or = 15 mol %. Cholesterol causes the decrease in both the polarity and the dipolar relaxation effects on the neighborhood of the fluorescent naphthalene moiety of Laurdan. Probably because of a cholesterol-induced increase in the bilayer packing, these effects do not occur continuously with the increase of cholesterol concentration in the bilayer. Cholesterol concentrations inducing higher Laurdan GP values have been determined at about 5, 10, 15, 30, and 45 mol % with respect to phospholipids. We propose that the formation of ordered molecular microdomains at critical cholesterol concentrations can explain the occurrence of the observed discontinuities.     

Extensive exchange of rat liver microsomal phospholipids

Liver microsomal fractions were prepared from rats injected with a single dose of choline [¹⁴C] methylchloride or with single or multiple doses of ³²P_i. Exchangeability of microsomal phospholipids was determined by incubation with an excess of mitochondria and phospholipid exchange proteins derived from beef heart, beef liver or rat liver. Labeled phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine and phosphatidylinositol were found to act as a single pool and were 85–95% exchangeable in 1–2 h. High latencies of mannose-6-phosphate phosphohydrolase activities and impermeability of microsomes to EDTA proved that phospholipid exchange proteins did not have access to the intracisternal space. If microsomal membranes are largely composed of phospholipid bilayers, the experiments suggest that one or more of the phospholipid classes in microsomal membranes undergo rapid translocation between the inner and outer portions of the bilayer.     

Fixed-bin analysis for statistical evaluation of continuous distributions of allelic data from VNTR loci, for use in forensic comparisons.

The detection of DNA polymorphisms by RFLP analysis is having a major impact on identity testing in forensic science. At present, this approach is the best effort a forensic scientist can make to exclude an individual who has been falsely associated with an evidentiary sample found at a crime scene. When an analysis fails to exclude a suspect as a potential contributor of an evidentiary sample, a means should be provided to assess suitable weight to the putative match. Most important, the statistical analysis should not place undue weight on a genetic profile derived from an unknown sample that is attributed to an accused individual. The method must allow for limitations in conventional agarose-submarine-gel electrophoresis and Southern blotting procedure, limited sample population data, possible subpopulation differences, and potential sampling error. A conservative statistical method was developed based on arbitrarily defined fixed bins. This approach permits classification of continuous allelic data, provides for a simple and portable data-base system, and is unlikely to underestimate the frequency of occurrence of a set of alleles. This will help ensure that undue weight is not placed on a sample attributed to an accused individual.     

Further observations on the properties of serum and tissue guanase from man and some animal species. Optimum pH and activation energy in the presence of 8-azaguanine.

The activation energy and the optimum pH of guanine deaminase in man, the rat, guinea pig and mouse were studied using 8-azaguanine as a substrate. The serum guanase in man and in all the animal species studied differs in activation energy from the guanase of the liver. In man, moreover, the serum guanase is also different from the brain and kidney enzyme. In the rat and guinea pig the brain enzyme has thermic activation energy different from the liver and kidney enzyme. The guanase of the serum and tissues of the guinea pig differs from the enzyme of the serum and tissues of man, rat and mouse for optimum pH.     

Mechanistic insights into the role of large carnivores for ecosystem structure and functioning

Large carnivores can exert top–down effects in ecosystems, but the size of these effects are largely unknown. Empirical investigation on the importance of large carnivores for ecosystem structure and functioning presents a number of challenges due to the large spatio-temporal scale and the complexity of such dynamics. Here, we applied a mechanistic global ecosystem model to investigate the influence of large-carnivore removal from undisturbed ecosystems. First, we simulated large-carnivore removal on the global scale to inspect the geographic pattern of top–down control and to disentangle the functional role of large carnivores in top–down control in different environmental contexts. Second, we conducted four small-scale ecosystem simulation experiments to understand direct and indirect changes in food-web structure under different environmental conditions. We found that the removal of top–down control exerted by large carnivores (> 21 kg) can trigger large trophic cascades, leading to an overall decrease in autotroph biomass globally. Furthermore, the loss of large carnivores resulted in an increase of mesopredators. The magnitude of these changes was positively related to primary productivity (NPP), in line with the ‘exploitation ecosystem hypothesis’. In addition, we found that seasonality in NPP dampened the magnitude of change following the removal of large carnivores. Our results reinforce the idea that large carnivores play a fundamental role in shaping ecosystems, and further declines and extinctions can trigger substantial ecosystem responses. Our findings also support previous studies suggesting that natural ecosystem dynamics have been severely modified and are still changing as a result of the widespread decline and extinction of large carnivores.     

Next Generation Semiconductor Based-Sequencing of a Nutrigenetics Target Gene (GPR120) and Association with Growth Rate in Italian Large White Pigs

The GPR120 gene (also known as FFAR4 or O3FAR1) encodes for a functional omega-3 fatty acid receptor/sensor that mediates potent insulin sensitizing effects by repressing macrophage-induced tissue inflammation. For its functional role, GPR120 could be considered a potential target gene in animal nutrigenetics. In this work we resequenced the porcine GPR120 gene by high throughput Ion Torrent semiconductor sequencing of amplified fragments obtained from 8 DNA pools derived, on the whole, from 153 pigs of different breeds/populations (two Italian Large White pools, Italian Duroc, Italian Landrace, Casertana, Pietrain, Meishan, and wild boars). Three single nucleotide polymorphisms (SNPs), two synonymous substitutions and one in the putative 3′-untranslated region (g.114765469C > T), were identified and their allele frequencies were estimated by sequencing reads count. The g.114765469C > T SNP was also genotyped by PCR-RFLP confirming estimated frequency in Italian Large White pools. Then, this SNP was analyzed in two Italian Large White cohorts using a selective genotyping approach based on extreme and divergent pigs for back fat thickness (BFT) estimated breeding value (EBV) and average daily gain (ADG) EBV. Significant differences of allele and genotype frequencies distribution was observed between the extreme ADG-EBV groups (P < 0.001) whereas this marker was not associated with BFT-EBV.