Selective enzymatic hydrolysis of aromatic diesters using esterase from Brevibacterium imperiale B222

Summary A practical procedure has been developed for the chemoselective microbial hydrolysis of aromatic dicarboxylic esters to give the corresponding monoesters, using cellular lysate and whole cell of Brevibacterium imperiale B222. The produced monoesters can be transformed into hydroxyacids, useful intermediates in the synthesis of polyesters.     

Water transport in human red cells: effects of 'non-inhibitory' sulfhydryl reagents

The water diffusional permeability of human red blood cells following exposure to various sulfhydryl group (SH) reagents have been studied using a nuclear magnetic resonance technique. Exposure of red blood cells up to 12 mM N-ethylmaleimide (NEM) or 10 mM 5,5'-dithio-bis(2-nitrobenzoic acid) (DTNE) alone does not affect water diffusion. In contrast, when DTNB treatment follows a preincubation of the cells with NEM, a small (18% at 37 degrees C) but significant inhibition of water permeability occurs. The NEM and DTNB treatment of the cells caused no change of the cell shape and volume or of the cell water volume. Consequently, the inhibition observed after NEM and DTNB treatment has a real significance.     

Freeze-fracture electron microscopic observations on the effects of sulphydryl group reagents on human erythrocyte membranes

Freeze-fracture electron microscopy of human red blood cells at pH 7.4 and 5.5 reveals the presence of membrane elevations (50-100 nm diameter). These are also observed after incubation of the erythrocytes with N-ethylmaleimide but not after incubation with p-chloromercuribenzene sulphonate. Neither of the sulphydryl-group reagents affects the distribution or size of intramembrane particles. The findings are discussed in the light of the effects of mercurials on erythrocyte membrane proteins.     

Bioavailability and dosing strategies of mineral in anaerobic mono‐digestion of maize straw

The influence of the bonding form distribution of Fe, Ni, Co and Mn and their potential bioavailability during the anaerobic degradation of maize straw was investigated. Two reactors were operated over 117 days at 37°C and different dosage strategies of mineral were studied in reactor (R2). Control reactor (R1) was metal‐limited over time. mineral supplementation (1 g L^?1) once a week reported the highest methane yield (257 mL g^?1 VS) with 30% of increment. Ni and Co predominated in their oxidizable bonding forms and Fe mainly existed as residual and oxidizable fractions. The potential bioavailability (Mn ?? Co ≈ Ni ? Fe) of R2 was higher comparing to R1. Metal deprivation in R1 led to depletion of both sequential extraction fractions and total metal concentrations until the end of the process. This study confirmed that the dosage strategy of mineral has a stimulatory effect on methane production from crop maize waste.     

Initiating Events in Direct Cardiomyocyte Reprogramming

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Intertidal benthic communities associated with the macroalgae <Emphasis Type="Italic">Iridaea cordata</Emphasis> and <Emphasis Type="Italic">Adenocystis utricularis</Emphasis> in King George Island,Antarctica

Antarctic benthos has been a main target in Antarctic research, but very few quantitative studies have been carried out in the littoral zone, which may be seasonally covered by macroalgae. In this work, we studied (1) cover and biomass of the macroalgae Iridaea cordata and Adenocystis utricularis, and (2) composition of macrobenthic assemblage associated with these macroalgal species at three locations at King George Island: Mareograph Beach (1 M), Tank’s Bay (2R) and Ardley Bay (3R). Iridaea cordata was collected by completely detaching the algae from the substrate, while A. utricularis was scraped. Adenocystis utricularis covered more than 80 % of the substrate at all locations, while coverage of Iridaea cordata was below 53 % or absent (3R). Fresh biomass of I. cordata was 0.8–61.4 g/individual and 4.7–93.0 g/100 cm² for A. utricularis. The assemblage associated with both macroalgae differed significantly between sites. The studied fauna was composed mainly of amphipods, gastropods and bivalves. Species diversity was higher in the community associated with A. utricularis. A total of ~27 ind/g DW were found associated with I. cordata, while ~112 ind/g DW were found associated with A. utricularis. The most abundant groups associated with I. cordata were amphipods at 1 M (57 %) and gastropods at 2R (46 %). Both groups were responsible for the dissimilarity between localities (62.50 %). The most abundant groups associated with A. utricularis were the gastropods at all localities reaching up to 82 % at 1 M. This study provides a first baseline on the diversity and abundance of benthic assemblages associated with intertidal macroalgae in the southwest of King George Island.     

Aortic valve disease in diabetes: Molecular mechanisms and novel therapies

Valve disease and particularly calcific aortic valve disease (CAVD) and diabetes (DM) are progressive diseases constituting a global health burden for all aging societies (Progress in Cardiovascular Diseases. 2014;56(6):565: Circulation Research. 2021;128(9):1344). Compared to non-diabetic individuals (The Lancet. 2008;371(9626):1800: The American Journal of Cardiology. 1983;51(3):403: Journal of the American College of Cardiology. 2017;69(12):1523), the diabetic patients have a significantly greater propensity for cardiovascular disorders and faster degeneration of implanted bioprosthetic aortic valves. Previously, using an original experimental model, the diabetic-hyperlipemic hamsters, we have shown that the earliest alterations induced by these conditions occur at the level of the aortic valves and, with time these changes lead to calcifications and CAVD. However, there are no pharmacological treatments available to reverse or retard the progression of aortic valve disease in diabetes, despite the significant advances in the field. Therefore, it is critical to uncover the mechanisms of valve disease progression, find biomarkers for diagnosis and new targets for therapies. This review aims at presenting an update on the basic research in CAVD in the context of diabetes. We provide an insight into the accumulated data including our results on diabetes-induced progressive cell and molecular alterations in the aortic valve, new potential biomarkers to assess the evolution and therapy of the disease, advancement in targeted nanotherapies, tissue engineering and the potential use of circulating endothelial progenitor cells in CAVD.     

Cytochrome c oxidase biogenesis: new levels of regulation

Eukaryotic cytochrome c oxidase (COX), the last enzyme of the mitochondrial respiratory chain, is a multimeric enzyme of dual genetic origin, whose assembly is a complicated and highly regulated process. COX displays a concerted accumulation of its constitutive subunits. Data obtained from studies performed with yeast mutants indicate that most catalytic core unassembled subunits are posttranslationally degraded. Recent data obtained in the yeast Saccharomyces cerevisiae have revealed another contribution to the stoichiometric accumulation of subunits during COX biogenesis targeting subunit 1 or Cox1p. Cox1p is a mitochondrially encoded catalytic subunit of COX which acts as a seed around which the full complex is assembled. A regulatory mechanism exists by which Cox1p synthesis is controlled by the availability of its assembly partners. The unique properties of this regulatory mechanism offer a means to catalyze multiple-subunit assembly. New levels of COX biogenesis regulation have been recently proposed. For example, COX assembly and stability of the fully assembled enzyme depend on the presence in the mitochondrial compartments of two partners of the oxidative phosphorylation system, the mobile electron carrier cytochrome c and the mitochondrial ATPase. The different mechanisms of regulation of COX assembly are reviewed and discussed.