Influence of lead nitrate oń dimethylnitrosamine intoxication

The effect of lead nitrate, an inhibitor of the hepatic drug-metabolizing enzyme system upon the acute hepatotoxicity of dimethylnitrosamine (DMN) was studied.Lead pretreatment significantly prevented polysomal disaggregation induced by the nitrosamine. Cell necrosis, evaluated morphologically and by the release of serum glutamic-pyruvic transaminase (GPT), was also diminised.The metabolism of DMN in rats pretreated with lead nitrate was investigated by following its clearance from blood and by determining, in vitro the demethylation of the nitrosamine. Lead increased, although not significantly, the clearance of DMN from blood, but it lowered the activity of DMN-demethylase 24 h after its administration.Finally, lead lowered the lethal effects of DMN. The mechanism by which lead influenced DMN toxicity is discussed.     

Carbonate Production by Benthic Communities on Shallow Coralgal Reefs of Abrolhos Bank,Brazil

The abundance of reef builders, non-builders and the calcium carbonate produced by communities established in Calcification Accretion Units (CAUs) were determined in three Abrolhos Bank shallow reefs during the period from 2012 to 2014. In addition, the seawater temperature, the irradiance, and the amount and composition of the sediments were determined. The inner and outer reef arcs were compared. CAUs located on the inner reef shelf were under the influence of terrigenous sediments. On the outer reefs, the sediments were composed primarily of marine biogenic carbonates. The mean carbonate production in shallow reefs of Abrolhos was 579 ± 98 g m^-2 y^-1. The builder community was dominated by crustose coralline algae, while the non-builder community was dominated by turf. A marine heat wave was detected during the summer of 2013–2014, and the number of consecutive days with a temperature above or below the summer mean was positively correlated with the turf cover increase. The mean carbonate production of the shallow reefs of Abrolhos Bank was greater than the estimated carbonate production measured for artificial structures on several other shallow reefs of the world. The calcimass was higher than the non-calcareous mass, suggesting that the Abrolhos reefs are still in a positive carbonate production balance. Given that marine heat waves produce an increase of turf cover on the shallow reefs of the Abrolhos, a decrease in the cover represented by reef builders and shifting carbonate production are expected in the near future.     

Adhesion to and degradation of marble by a micrococcus strain isolated from it

A Micrococcus strain occurring frequently and isolated multiple times from stones was studied for its ability to adhere to substrates and to produce exopolysaccharides or extracellular polymeric substances, one of the essential prerequisites for biofilm formation. Measurements of the biodeterioration activity of this strain in terms of (i) pH drop, (ii) organic acid production, and (iii) weight loss of marble slabs demonstrated the highly aggressive biodeteriorating potential of the strain in question.     

The biomarkers of fetal growth in intrauterine growth retardation and large for gestational age cases: from adipocytokines to a metabolomic all-in-one tool

Adipose tissue is no longer considered as inert; the literature describes the role it plays in the production of many substances, such as adiponectin, visfatin, ghrelin, S100B, apelin, TNF, IL-6 and leptin. These molecules have specific roles in humans and their potential as biomarkers useful for identifying alterations related to intrauterine growth retardation and large for gestational age neonates is emerging. Infants born in such conditions have undergone metabolic changes, such as fetal hypo- or hyperinsulinemia, which may lead to development of dysmetabolic syndrome and other chronic diseases in adulthood. In this review, these biomarkers are analyzed specifically and it is discussed how metabolomics may be an advantageous tool for detection, discrimination and prediction of metabolic alterations and diseases. Thus, a holistic approach, such as metabolomics, could help the prevention and early diagnosis of metabolic syndrome.     

Escherichia coli S-adenosylhomocysteine/5''-methylthioadenosine nucleosidase. Purification, substrate specificity and mechanism of action.

Ca2+-activated protein phosphatase activity was demonstrated in mouse pancreatic acinar cytosol with alpha-casein and skeletal-muscle phosphorylase kinase as substrates. This phosphatase activity preferentially dephosphorylated the alpha subunit of phosphorylase kinase. After DEAE-cellulose chromatography, the Ca2+-activated phosphatase activity became dependent on exogenous calmodulin for maximal activity. Half-maximal activation was achieved at 0.5 +/- 0.1 microM-Ca2+. Trifluoperazine completely inhibited Ca2+-activated phosphatase activity, with half-maximal inhibition occurring at 8.5 +/- 0.6 microM. Mn2+, but not Mg2+, at 1 mM concentration could substitute for Ca2+ in eliciting full enzyme activation. The apparent Mr of the phosphatase as determined by Sephadex G-150 chromatography was 93000 +/- 1000. Submitting active fractions obtained after Sephadex chromatography to calmodulin affinity chromatography resulted in the resolution of a major protein of Mr 55500 +/- 300. In conclusion, Ca2+-activated protein phosphatase activity has been identified in exocrine pancreas and has several features in common with Ca2+-activated calmodulin-dependent protein phosphatases previously isolated from brain and skeletal muscle. It is possible that this Ca2+-activated phosphatase may utilize as substrates certain acinar-cell phosphoproteins previously shown to undergo dephosphorylation in response to Ca2+-mediated secretagogues.