Is redox metabolism connected with Circadian Rhythm?

Highlights | Carolina G. FernandesIs redox metabolism connected with Circadian Rhythm?

by Carolina Gonçalves Fernandes

Circadian Rhythm is any biological process that temporally organizes behavioral, physiological, and molecular events around the 24h day-night cycle. This process has evolved over approximately 2.5 billion years ago at the Great Oxidation Event. The later involved increases in atmospheric oxygen levels that simulatenwously enabled organisms to resonate with their environment such that their internal cycles anticipate and match external rhythms on Earth. In mammals, this rhythmicity is controlled by the hypothalamic suprachiasmatic nuclei (SCN) receiving retina signals and “translating” them into each tissue/organ that commonly responds using the transcription/translation


The two faces of peroxiredoxins

by Larissa Anastácio da Costa Carvalho

In the antiquity, many cities protected their territories by surrounding fortifications, with giant gates and arches working as unique gateways. The Roman god Janus, known as the protector of entrances or new-beginnings, is represented by a head with two faces in opposite directions. The two faces of Janus symbolize the duality of nature. Well, nature itself is marked by dichotomy. What in nature cannot be good and bad at the same time? That is the origin of the term Janus effect.

A remarkable example of the Janus effect is the mustard gas (1,1-thiobis-2-chloroethane). Used as a chemical weapon during World War I, it causes serious inflammation of the


The controversy about antibiotic lethality and reactive oxygen species

by José Freire da Silva Neto

Antibiotics are powerful compounds in our battle against bacterial diseases. Despite their miraculous efficacy over decades, nowadays we are faced with the global spreading of antibiotic resistance and the decrease of our antibiotic arsenal. For many years, we learned that antibiotics exert their effect by direct interaction with different primary bacterial targets, causing killing (bactericidal drugs) or growth inhibition (bacteriostatic drugs). In 2007, an influential paper from the Collins laboratory [1] placed reactive oxygen species (ROS) as central players in the mechanism of cell death induced by bactericidal antibiotics. Ever since


A comprehensive approach to identify redox and non-redox targets of Trx-like proteins

by Lia S. Nakao

Like the old dictum that says “birds of a feather flock together”, understanding the specific partners of a given protein provides an important clue about its function. Thioredoxin 1 (Trx1) is a well-known redox protein that contains a CXXC motif (cysteines residues flanking two aminoacid residues), responsible for its disulfide reductase function. The first (C-terminal) Cys of the motif attacks the disulfide of the target protein, producing a short lived mixed disulfide, which is reduced by the second (N-terminal resolving) Cys, releasing Trx1 and the target, in the oxidized and reduced forms, respectively. If the resolving Cys is replaced by a non-redox residue, such as


More on thiol switches… a novel redox mechanism regulating proteolysis in facultative anaerobes

by Thaís L. S. Araújo*

Protein homeostasis (proteostasis) is fundamental to living organisms and even if we only judge from the number and intricacies of existing mechanisms to deal with this process, one can conclude it is a priority issue for nature [1]. An intriguing problem has been to understand how facultative anaerobic bacteria adapt their proteostatic mechanisms during the transition from anaerobic to aerobic conditions. In a recent article [2,3], it was found that an interesting


Succinate accumulates during ischemia forcing mitochondrial complex I to operate in reversal, while producing oxidant species during reperfusion

by José Carlos Toledo

Ischemia-reperfusion (IR) is a process where blood supply (thus oxygen supply) to an organ is interrupted and then restored. While reperfusion is essential for survival, it is accompanied by a burst of mitochondrial generation of redox species and intermediates such as superoxide and hydrogen peroxide. Such species associate with derived ischemic tissue injury, underling disorders such as heart attack and stroke [1]. Nonetheless, IR mitochondrial ROS production has been considered a nonspecific consequence of a dysfunctional interaction of mitochondrial redox


Saving the planet by eating healthier food

by Ignacio Amigo*

It is well established that as countries develop, their inhabitants change their alimentary habits from complex carbohydrates and fiber to diets with a higher proportion of fats, saturated fats and sugars, a phenomenon that has been termed “nutrition transition”. The link between these new food habits and the deterioration of health is notorious and underlies the great interest that consumers have developed in the last years over “organic” and “macrobiotic” aliments. Less obvious, but probably as important, is the association between the alimentary habits and greenhouse gases emissions. When we think about climate change, we usually picture big factories releasing


The new roles of cardiolipin in ROS-mediated signalling

Cytochrome c

by Alberto Lévano-Martinez

Cardiolipin, the signature phospholipid of mitochondria, has been extensively studied as this organelle’s main structural and regulatory lipid. It exerts influential roles in the catalytic activity of key components of the oxidative phosphorylation under physiological conditions. However, recents advances in mitochondrial physiology have uncovered roles of this phospholipid in pathophysiological situations such as apoptosis, or in Barth syndrome. Cardiolipin anchors cytochrome c to the outer face of the inner mitochondrial membrane, which favors the electron transfer to the terminal component of the respiratory chain (Complex IV). However, during oxidative