β-Endorphin Is a Potent Inhibitor of Thymidine Incorporation into DNA via μ and κ-Opioid Receptors in Fetal Rat Brain Cell Aggregates in Culture

Abstract: Thymidine incorporation into DNA was inhibited dose-dependently by β-endorphin in rat fetal brain cell aggregate cultures. The inhibition was reversed partially by μ (cyclic D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr amide) or k (norbinaltorphimine) antagonists. Complete blockade of the β-endorphin inhibitory effect was achieved only on concomitant exposure to both antagonists. Eadie–Hofstee analysis revealed that β-endorphin inhibited thymidine incorporation noncompetitively. In the presence of protease inhibitors, β-endorphin decreased thymidine incorporation with an IC₅₀ of 0.7 n M . Truncated and N -acetylated β-endorphin derivatives, which bind with low affinity to opioid receptors, did not affect thymidine incorporation. These findings indicate that β-endorphin at physiological concentrations can regulate thymidine incorporation in cultured brain cells.     

Methodology for the implementation of monitoring plans with different spatial and temporal scales of plant protection products residues in water bodies based on site-specific environmental pressures assessments

Abstract

The awareness of plant protection products residues causing problems in water bodies is increasing more and more. A lot of effort is being made by countries in investigating the situation of diffuse pesticide pollution. This article illustrates a new methodology developed for the implementation of monitoring plans for plant protection products residues in rivers, lakes and groundwater, at river basin scale, based on an operational workflow which, by integrating different databases, let to evaluate site-specific environmental pressures affecting the definition of the related monitoring networks. It follows that sampling and analytical activities, carried out in the monitoring network nodes, not only are functional to water bodies ecological and chemical quality status assessment but are able to highlight possible compromises of environmental balance in agro-ecosystems, deriving from plant protection products use, through the application of environmental modeling able to bring out evolutive trends. This information would allow the Administrators to take increasingly effective initiatives both in the field of controls and authorizations for particular substances, in the light of the negative effects shown, and in the field of spatial planning, being able to dispose of the necessary knowledge in order to take safeguard measures before a certain evolutionary process of degradation becomes irreversible.     

Association between Low‐Molecular Weight Apolipoprotein(a) Isoforms and Obesity in Italian Women

Objective: Low‐molecular weight (MW) apolipoprotein(a) [apo(a)] isoforms are closely associated with an increased incidence of atherothrombotic disease, prevalence of which is higher in obese individuals, particularly in women. The hypothesis of this study was to assess whether there are differences in the distribution of apo(a) phenotypes between obese patients and healthy controls. Research Methods and Procedures: One hundred three obese Italian women (BMI ≥ 30.0 kg/m²) were enrolled in the study, and apo(a) phenotyping was performed in all subjects. The prevalence of low‐MW apo(a) isoforms, detected in plasma samples of our obese women, was compared with that found in a control group of 84 normal‐weight, never‐obese (BMI < 25.0 kg/m²), age‐matched women. Results: The distribution of apo(a) isoforms in the population of obese women was significantly different from that found in normal‐weight female subjects. In particular, the percentage of subjects in the obese group with at least one apo(a) isoform of low MW was significantly higher than that in the control group (51.4% vs. 32.1%, p = 0.0079). Discussion: Our results seem to suggest the possibility that small‐sized apo(a) isoforms may be used together with other traditional risk factors to better assess the overall predisposition to atherothrombotic disease in obese women.     

The Tat system of Gram-positive bacteria

The twin-arginine protein translocation (Tat) system has a unique ability to translocate folded and co-factor-containing proteins across lipid bilayers. The Tat pathway is present in bacteria, archaea and in the thylakoid membranes of chloroplasts and, depending on the organism and environmental conditions, it can be deemed important for cell survival, virulence or bioproduction. This review provides an overview of the current understanding of the Tat system with specific focus on Gram-positive bacteria. The ‘universal minimal Tat system’ is composed of a TatA and a TatC protein. However, this pathway is more commonly composed of two TatA-like proteins and one TatC protein. Often the TatA-like proteins have diverged to have two different functions and, in this case, the second TatA-like protein is usually referred to as TatB. The correct folding and/or incorporation of co-factors are requirements for translocation, and the known quality control mechanisms are examined in this review. A number of examples of crosstalk between the Tat system and other protein transport systems, such as the Sec–YidC translocon and signal peptidases or sheddases are also discussed. Further, an overview of specific Gram-positive bacterial Tat systems found in monoderm and diderm species is detailed. Altogether, this review highlights the unique features of Gram-positive bacterial Tat systems and pinpoints key questions that remain to be addressed in future research. This article is part of a Special Issue entitled: Protein trafficking and secretion in bacteria. Guest Editors: Anastassios Economou and Ross Dalbey.