Transdução de sinal mitocondrial: mero acaso, fortuita necessidade ou design inteligente?

quarta-feira, novembro 16, 2022

Mitochondrial signal transduction

Martin Picard, Orian S. Shirihai

Open Access DOI:


The analogy of mitochondria as powerhouses has expired. Mitochondria are living, dynamic, maternally inherited, energy-transforming, biosynthetic, and signaling organelles that actively transduce biological information. We argue that mitochondria are the processor of the cell, and together with the nucleus and other organelles they constitute the mitochondrial information processing system (MIPS). In a three-step process, mitochondria (1) sense and respond to both endogenous and environmental inputs through morphological and functional remodeling; (2) integrate information through dynamic, network-based physical interactions and diffusion mechanisms; and (3) produce output signals that tune the functions of other organelles and systemically regulate physiology. This input-to-output transformation allows mitochondria to transduce metabolic, biochemical, neuroendocrine, and other local or systemic signals that enhance organismal adaptation. An explicit focus on mitochondrial signal transduction emphasizes the role of communication in mitochondrial biology. This framework also opens new avenues to understand how mitochondria mediate inter-organ processes underlying human health.

Keywords signal transduction evolution mitochondrial networks steroid hormones receptors amplification membrane potential communication mito-nuclear signaling tissuespecific mitotypes stress  responses metabokines mitokines energyhealth

FREE PDF GRATIS: Cell Metabolism

Renovando a taxonomia de Lineu: uma proposta para reestruturar os níveis mais altos do Sistema Natural.

segunda-feira, novembro 14, 2022

Renewing Linnaean taxonomy: a proposal to restructure the highest levels of the Natural System

Peter T. S. van der Gulik, Wouter D. Hoff, David Speijer

First published: 10 November 2022


During the last century enormous progress has been made in the understanding of biological diversity, involving a dramatic shift from macroscopic to microscopic organisms. The question now arises as to whether the Natural System introduced by Carl Linnaeus, which has served as the central system for organizing biological diversity, can accommodate the great expansion of diversity that has been discovered. Important discoveries regarding biological diversity have not been fully integrated into a formal, coherent taxonomic system. In addition, because of taxonomic challenges and conflicts, various proposals have been made to abandon key aspects of the Linnaean system. We review the current status of taxonomy of the living world, focussing on groups at the taxonomic level of phylum and above. We summarize the main arguments against and in favour of abandoning aspects of the Linnaean system. Based on these considerations, we conclude that retaining the Linnaean Natural System provides important advantages. We propose a relatively small number of amendments for extending this system, particularly to include the named rank of world (Latin alternative mundis) formally to include non-cellular entities (viruses), and the named rank of empire (Latin alternative imperium) to accommodate the depth of diversity in (unicellular) eukaryotes that has been uncovered. We argue that in the case of both the eukaryotic domain and the viruses the cladistic approach intrinsically fails. However, the resulting semi-cladistic system provides a productive way forward that can help resolve taxonomic challenges. The amendments proposed allow us to: (i) retain named taxonomic levels and the three-domain system, (ii) improve understanding of the main eukaryotic lineages, and (iii) incorporate viruses into the Natural System. Of note, the proposal described herein is intended to serve as the starting point for a broad scientific discussion regarding the modernization of the Linnaean system.

FREE PDF GRATIS: Biological Reviews

Erik Svensson (Universidade de Lund) 'falou e disse': o estudo da evolução está fraturando – e isso pode ser uma coisa boa!

sábado, novembro 12, 2022

The study of evolution is fracturing – and that may be a good thing

Published: November 9, 2022 4.24pm GMT

Author: Erik Svensson

Professor (Evolutionary Ecology Unit, Department of Biology), Lund University

Disclosure statement:

Erik Svensson receives funding from from the Swedish Research Council (VR; grant no. 2020-03123).

How will life on Earth and the ecosystems that support it adapt to climate change? Which species will go extinct – or evolve into something new? How will microbes develop further resistance to antibiotics?

These kinds of questions, which are of fundamental importance to our way of life, are all a focus for researchers who study evolution and will prove increasingly important as the planet heats up.

But finding the answers isn’t the only challenge facing evolutionary biology. Charles Darwin’s theories might be over 150 years old but major questions about how evolution works are far from settled.

Evolutionary biology is now undergoing one of the most intense debates it has had for more than a generation. And how this debate plays out could have a significant impact on the future of this scientific field.

Some biologists and philosophers claim that evolutionary biology needs reform, arguing that traditional explanations for how organisms change through time that scientists have assumed since the 1930s are holding back the assimilation of novel findings

Contemporary evolutionary biology, a vocal minority argue, is incomplete. The dominant and traditional view of the field is too preoccupied with how the genes in a population change over time. This neglects, these critics argue, how individual organisms shape their environments and adjust themselves during their lifetimes to survive and reproduce.

Some go so far as to say that evolutionary theory itself is in crisis and must be replaced with something new.

Not all biologists are convinced. Some argue that repeated calls for reform are mistaken and can actually hinder progress.


READ MORE HERE: The Conversation

Universo 'assimétrico' pode significar revisão do modelo cosmológico padrão.

domingo, novembro 06, 2022

A Challenge to the Standard Cosmological Model

Nathan J. Secrest 1, Sebastian von Hausegger 2, Mohamed Rameez 3, Roya Mohayaee 2,4, and Subir Sarkar 2

Published 2022 September 28 • © 2022. The Author(s). Published by the American Astronomical Society.

The Astrophysical Journal Letters, Volume 937, Number 2


We present the first joint analysis of catalogs of radio galaxies and quasars to determine whether their sky distribution is consistent with the standard ΛCDM model of cosmology. This model is based on the cosmological principle, which asserts that the universe is statistically isotropic and homogeneous on large scales, so the observed dipole anisotropy in the cosmic microwave background (CMB) must be attributed to our local peculiar motion. We test the null hypothesis that there is a dipole anisotropy in the sky distribution of radio galaxies and quasars consistent with the motion inferred from the CMB, as is expected for cosmologically distant sources. Our two samples, constructed respectively from the NRAO VLA Sky Survey and the Wide-field Infrared Survey Explorer, are systematically independent and have no shared objects. Using a completely general statistic that accounts for correlation between the found dipole amplitude and its directional offset from the CMB dipole, the null hypothesis is independently rejected by the radio galaxy and quasar samples with p-values of 8.9 × 10−3 and 1.2 × 10−5, respectively, corresponding to 2.6σ and 4.4σ significance. The joint significance, using sample-size-weighted Z-scores, is 5.1σ. We show that the radio galaxy and quasar dipoles are consistent with each other and find no evidence for any frequency dependence of the amplitude. The consistency of the two dipoles improves if we boost to the CMB frame assuming its dipole to be fully kinematic, suggesting that cosmologically distant radio galaxies and quasars may have an intrinsic anisotropy in this frame.

FREE PDF GRATIS: The Astrophysical Journal Letters