Changes in the microsomal proteome of tomato fruit during ripening

The variations in the membrane proteome of tomato fruit pericarp during ripening have been investigated by mass spectrometry-based label-free proteomics. Mature green (MG30) and red ripe (R45) stages were chosen because they are pivotal in the ripening process: MG30 corresponds to the end of cellular expansion, when fruit growth has stopped and fruit starts ripening, whereas R45 corresponds to the mature fruit. Protein patterns were markedly different: among the 1315 proteins identified with at least two unique peptides, 145 significantly varied in abundance in the process of fruit ripening. The subcellular and biochemical fractionation resulted in GO term enrichment for organelle proteins in our dataset, and allowed the detection of low-abundance proteins that were not detected in previous proteomic studies on tomato fruits. Functional annotation showed that the largest proportion of identified proteins were involved in cell wall metabolism, vesicle-mediated transport, hormone biosynthesis, secondary metabolism, lipid metabolism, protein synthesis and degradation, carbohydrate metabolic processes, signalling and response to stress

Depletion of ATP-citrate lyase (ATPCL) affects chromosome integrity without altering histone acetylation in Drosophila mitotic cells

The Citrate Lyase (ACL) is the main cytosolic enzyme that converts the citrate exported from mitochondria by the SLC25A1 carrier in Acetyl Coenzyme A (acetyl-CoA) and oxaloacetate. Acetyl-CoA is a high-energy intermediate common to a large number of metabolic processes including protein acetylation reactions. This renders ACL a key regulator of histone acetylation levels and gene expression in diverse organisms including humans. We have found that depletion of Drosophila ATPCL, the fly ortholog of human ACL, reduced levels of Acetyl CoA but, unlike its human counterpart, does not affect global histone acetylation and gene expression. Nevertheless, reduced ATPCL levels caused evident, although moderate, mitotic chromosome breakage suggesting that this enzyme plays a partial role in chromosome stability. These defects did not increase upon X-ray irradiation, indicating that they are not dependent on an impairment of DNA repair. Interestingly, depletion of ATPCL drastically increased the frequency of chromosome breaks associated to mutations in scheggia, which encodes the ortholog of the mitochondrial citrate carrier SLC25A1 that is also required for chromosome integrity and histone acetylation. Our results indicate that ATPCL has a dispensable role in histone acetylation and prevents massive chromosome fragmentation when citrate efflux is altered

Ergosterol reduction impairs mitochondrial DNA maintenance in S. cerevisiae

Sterols are essential lipids, involved in many biological processes. In Saccharomyces cerevisiae, the enzymes of the ergosterol biosynthetic pathway (Erg proteins) are localized in different cellular compartments. With the aim of studying organelle interactions, we discovered that Erg27p resides mainly in Lipid Droplets (LDs) in respiratory competent cells, while in absence of respiration, is found mostly in the ER. The results presented in this paper demonstrate an interplay between the mitochondrial respiration and ergosterol production: on the one hand, rho° cells show lower ergosterol content when compared with wild type respiratory competent cells, on the other hand, the ergosterol biosynthetic pathway influences the mitochondrial status, since treatment with ketoconazole, which blocks the ergosterol pathway, or the absence of the ERG27 gene, induced rho° production in S. cerevisiae. The loss of mitochondrial DNA in the ∆erg27 strain is fully suppressed by exogenous addition of ergosterol. These data suggest the notion that ergosterol is essential for maintaining the mitochondrial DNA attached to the inner mitochondrial membrane

A Circular Restricted n-body Problem

This paper introduces the Circular Restricted n-Body Problem (CRNBP), an extension of the bicircular restricted four-body problem (BCR4BP) designed to describe the dynamics of an n-body system. In the CRNBP, each massive body in the system is constrained to follow a Keplerian motion, similar to the BCR4BP's artificial constraint. The CRNBP is an efficient alternative for trajectory design in multiple-body systems, particularly for outer planetary systems, as it requires integrating only six first-order ordinary differential equations compared to the 6N equations in an ephemerides model. By reproducing complex dynamical behaviors observed in ephemerides n-body problems, we demonstrate the structural stability of the CRNBP. Additionally, we propose a straightforward approach to relate the CRNBP with ephemerides, enabling the exploration of trajectory design possibilities before committing to a dedicated ephemerides analysis. This allows for the identification of general dynamical behaviors and provides valuable insights into the dynamics of multiple body systems. Finally, illustrative examples highlight the richness of trajectories and potential advantages of using the CRNBP for designing complex trajectories in outer planetary systems. The CRNBP proves to be a valuable tool for preliminary trajectory design, facilitating the identification of low-energy trajectories and providing a foundation for further exploration in future dedicated studies.Comment: Draft version of the article published in the JGC

Autonomous and Robust Orbit-keeping for Small Body Missions

This article presents a path-following control law for autonomous orbital maintenance of small body missions. The control law is robust, stable, and capable of controlling only the orbital geometry, allowing the spacecraft to operate with idle-thruster periods. It is entirely analytical and suitable for real-time operations. The control law is inspired by the two-body problem and uses sliding mode control theory to ensure robustness against bounded disturbances. Practical considerations, such as measurement noise, thruster limitations, and hysteresis-based control switching, are taken into account. The proposed control law is demonstrated and validated through several examples, including orbit-keeping around the asteroid Bennu, showing its feasibility and efficiency for small body missions. The results indicate that the control law can achieve precise and safe orbit maintenance with minimal fuel consumption, making it a valuable asset for autonomous space missions.Comment: Draft of the paper published by the JGC

one step one lane chemical dna sequencing by n methylformamide in the presence of metal ions

We report on a chemical method that allows DNA sequencing by a single reaction. It is based on treatment of 5′-end-labeled DNA with N-methylformamide in the presence of manganese. This method allows the manipulation of samples to be kept to a minimum and consists of a single chemical step that requires about 30 minutes to complete base degradation, phosphodiester bond cleavage and denaturation. Examples of one-treatment, one-lane DNA sequencing of both radioactively and fluorescently 5′-end-labeled DNAs are reported

The role of histone lysine methylation in the response of mammalian cells to Ionizing radiation

Eukaryotic genomes are wrapped around nucleosomes and organized into different levels of chromatin structure. Chromatin organization has a crucial role in regulating all cellular processes involving DNA-protein interactions, such as DNA transcription, replication, recombination and repair. Histone post-translational modifications (HPTMs) have a prominent role in chromatin regulation, acting as a sophisticated molecular code, which is interpreted by HPTM-specific effectors. Here, we review the role of histone lysine methylation changes in regulating the response to radiation-induced genotoxic damage in mammalian cells. We also discuss the role of histone methyltransferases (HMTs) and histone demethylases (HDMs) and the effects of the modulation of their expression and/or the pharmacological inhibition of their activity on the radio-sensitivity of different cell lines. Finally, we provide a bioinformatic analysis of published datasets showing how the mRNA levels of known HMTs and HDMs are modulated in different cell lines by exposure to different irradiation conditions

Molecular signatures of the aging brain: finding the links between genes and phenotypes

Aging is associated with cognitive decline and increased vulnerability to neurodegenerative diseases. The progressive extension of the average human lifespan is bound to lead to a corresponding increase in the fraction of cognitively impaired elderly individuals among the human population, with an enormous societal and economic burden. At the cellular and tissue levels, cognitive decline is linked to a reduction in specific neuronal subpopulations, a widespread decrease in synaptic plasticity and an increase in neuroinflammation due to an enhanced activation of astrocytes and microglia, but the molecular mechanisms underlying these functional changes during normal aging and in neuropathological conditions remain poorly understood. In this review, we summarize very recent and outstanding progress in elucidating the molecular changes associated with cognitive decline through the genome-wide profiling of aging brain cells at different molecular levels (genomic, epigenomic, transcriptomic, proteomic). We discuss how the correlation of different molecular and phenotypic traits driven by mathematical and computational analyses of large datasets has led to the prediction of key molecular nodes of neurodegenerative pathways, and provide a few examples of candidate regulators of cognitive decline identified with these approaches. Furthermore, we highlight the dysregulation of the synaptic transcriptome in neuronal cells and of the inflammatory transcriptome in glial cells as some of the key events during normal and neuropathological human brain aging

A role for microbial selection in frescoes' deterioration in Tomba degli Scudi in Tarquinia, Italy

Mural paintings in the hypogeal environment of the Tomba degli Scudi in Tarquinia, Italy, show a quite dramatic condition: the plaster mortar lost his cohesion and a white layer coating is spread over almost all the wall surfaces. The aim of this research is to verify if the activity of microorganisms could be one of the main causes of deterioration and if the adopted countermeasures (conventional biocide treatments) are sufficient to stop it. A biocide treatment of the whole environment has been carried out before the conservative intervention and the tomb has been closed for one month. When the tomb was opened again, we sampled the microorganisms present on the frescoes and we identified four Bacillus species and one mould survived to the biocide treatment. These organisms are able to produce spores, a highly resistant biological form, which has permitted the survival despite the biocide treatment. We show that these Bacillus strains are able to produce calcium carbonate and could be responsible for the white deposition that was damaging and covering the entire surface of the frescoes. Our results confirm that the sanitation intervention is non always resolutive and could even be deleterious in selecting harmful microbial communities