452 research outputs found
Identification of a novel transporter for dicarboxylates and tricarboxylates in plant mitochondria. Bacterial expression, reconstitution, functional characterization, and tissue distribution.
A cDNA from Arabidopsis thaliana and four related cDNAs from Nicotiana tabacum that we have isolated encode hitherto unidentified members of the mitochondrial carrier family. These proteins have been overexpressed in bacteria and reconstituted into phospholipid vesicles. Their transport properties demonstrate that they are orthologs/isoforms of a novel mitochondrial carrier capable of transporting both dicarboxylates (such as malate, oxaloacetate, oxoglutarate, and maleate) and tricarboxylates (such as citrate, isocitrate, cis-aconitate, and trans-aconitate). The newly identified dicarboxylate-tricarboxylate carrier accepts only the single protonated form of citrate (H-citrate2-) and the unprotonated form of malate (malate2-) and catalyzes obligatory, electroneutral exchanges. Oxoglutarate, citrate, and malate are mutually competitive inhibitors, showing K(i) close to the respective K(m). The carrier is expressed in all plant tissues examined and is largely spread in the plant kingdom. Furthermore, nitrate supply to nitrogen-starved tobacco plants leads to an increase in its mRNA in roots and leaves. The dicarboxylate-tricarboxylate carrier may play a role in important plant metabolic functions requiring organic acid flux to or from the mitochondria, such as nitrogen assimilation, export of reducing equivalents from the mitochondria, and fatty acid elongation
Mitochondrial Role in Intrinsic Apoptosis Induced by a New Synthesized Chalcone in Hepatocellular Carcinoma Cells
Hepatocellular carcinoma (HCC) is the most common type of liver cancer and the fourth cause of cancer-related deaths worldwide. Presently, a few drugs are available for HCC treatment and prevention, including both natural and synthetic compounds. In this study, a new chalcone, (E)-1-(2,4,6-triethoxyphenyl)-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one (ETTC), was synthesized and its effects and mechanisms of action over human hepatoma cells were investigated. Cytotoxic activity was revealed in HCC cells, while no effects were observed in normal hepatocytes. In HCC cells, ETTC caused subG1 cell cycle arrest and apoptosis, characterized by nuclear fragmentation. The activation of caspases 3/7 and 9, the increase in pro-apoptotic BAX, and the decrease in anti-apoptotic BCL-2 suggest the activation of the intrinsic pathway of apoptosis. ETTC mitochondrial targeting is confirmed by the reduction in mitochondrial membrane potential and Complex I activity together with levels of superoxide anion increasing. Our outcomes prove the potential mitochondria-mediated antitumor effect of newly synthesized chalcone ETTC in HCC
How to Improve the Quality of Life of Patients with Prostate Cancer Treated with Hormone Therapy?
Prostate cancer (PC) is a hormone-sensitive tumor. Androgen deprivation therapy (ADT) is the cornerstone of systemic therapy for patients with intermediate or high-risk localized, recurrent, and metastatic prostate cancer. Although generally well tolerated, ADT can lead to short- and long-term adverse events that can worsen the quality of life of patients with PC. In the last decade, the introduction of novel generation androgen receptor pathway inhibitors (ARPI) has resulted in an improvement in the prognosis of patients with metastatic PC when used in combination with ADT. The use of ARPI in increasingly early stages of the disease determines a longer exposure of patients to these treatments. Although ARPIs are normally well-tolerated drugs, they generally cause an increase in toxicity compared to ADT alone, being able to worsen some adverse events already induced by ADT or leading to the development of specific side effects. Although there are no specific treatments for all the adverse events induced by hormonal therapies, it is essential to know the possible toxicities induced by the different treatments and to start procedures to prevent and/or recognize and consequently treat them early in order to not compromise the quality of life of the patients with PC. The aim of this review is to describe the adverse events induced by hormonal therapies. We will first describe the side effects induced by both ADT and ARPI and then the specific adverse events of the different ARPIs. Furthermore, we will try to highlight the possible therapeutic options to prevent or mitigate the toxicity induced by hormone therapies in order to improve the quality of life of the patients with PC
Exploitation of Microalgae Biomass Under an Integrated Biorefinery Approach
As known, microalgae are an appealing source of chemicals and high-value compounds which find application in nutraceuticals, cosmetics and pharmaceutics. Fatty acids (FA), in particular, have drawn attention to the possibility of employing them as a source of biodiesel alternatively to fossil fuels. In addition, several lipid derivatives have been found in microalgae and may be employed in several biotechnological applications. Hydroxy fatty acids can be substrates for several industrial applications thanks to their functionalization, which increases their reactivity and, for this reason, can be used as functional building blocks to produce a multitude of bio-based materials. Recently, a promising method for the chemical modification of unsaturated-FAs (U-FA) has appeared. In fact, U-FA may be modified by members of the hydratase enzyme family to produce saturated and unsaturated hydroxy fatty acids with high stereo- and regio-selectivity. These enzymes are able to introduce a water molecule to the double bond present in the free fatty acids (FFA) Oleic Acid (OA), Linoleic Acid (LA), producing 10-hydroxy fatty acids (10-hydroxy-FAs).
Furthermore, the carbohydrate component of the microalgal biomass may be converted into furfuryl compounds and, in particular in 5-hydroxyl methyl furfural (5-HMF). This is one of the chemical bio-compound different from petroleum-derived ones with the highest added value and may be obtained through lignocellulosic biomasses or hexoses sugars through acid catalysis. It is defined platform molecule because it is the precursor of several compounds for the chemical industry.
In this work, we aimed to optimize a circular bioprocess by performing, starting from the same biomass, two different processes: the biotransformation of microalgal FFAs through the employment of a genetically modified E. coli on one side, and the conversion of the remaining biomass in furfuryl products. The first process allowed the production of very interesting lipid derivatives with biotechnological applications, including 10 hydroxy-stearic acid and 10-hydroxy-octadecenoic acid. The second process was obtained through heterogeneous catalysis based on niobium phosphate. This procedure represents a high-innovative application of microalgal biomass and allows the simultaneous exploitation of FAs and carbohydrates. This may result in an increase in the commercial value of microalgal biomass
A chemical survey of exoplanets with ARIEL
Thousands of exoplanets have now been discovered with a huge range of masses, sizes and orbits: from rocky Earth-like planets to large gas giants grazing the surface of their host star. However, the essential nature of these exoplanets remains largely mysterious: there is no known, discernible pattern linking the presence, size, or orbital parameters of a planet to the nature of its parent star. We have little idea whether the chemistry of a planet is linked to its formation environment, or whether the type of host star drives the physics and chemistry of the planet’s birth, and evolution. ARIEL was conceived to observe a large number (~1000) of transiting planets for statistical understanding, including gas giants, Neptunes, super-Earths and Earth-size planets around a range of host star types using transit spectroscopy in the 1.25–7.8 μm spectral range and multiple narrow-band photometry in the optical. ARIEL will focus on warm and hot planets to take advantage of their well-mixed atmospheres which should show minimal condensation and sequestration of high-Z materials compared to their colder Solar System siblings. Said warm and hot atmospheres are expected to be more representative of the planetary bulk composition. Observations of these warm/hot exoplanets, and in particular of their elemental composition (especially C, O, N, S, Si), will allow the understanding of the early stages of planetary and atmospheric formation during the nebular phase and the following few million years. ARIEL will thus provide a representative picture of the chemical nature of the exoplanets and relate this directly to the type and chemical environment of the host star. ARIEL is designed as a dedicated survey mission for combined-light spectroscopy, capable of observing a large and well-defined planet sample within its 4-year mission lifetime. Transit, eclipse and phase-curve spectroscopy methods, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allow us to measure atmospheric signals from the planet at levels of 10–100 part per million (ppm) relative to the star and, given the bright nature of targets, also allows more sophisticated techniques, such as eclipse mapping, to give a deeper insight into the nature of the atmosphere. These types of observations require a stable payload and satellite platform with broad, instantaneous wavelength coverage to detect many molecular species, probe the thermal structure, identify clouds and monitor the stellar activity. The wavelength range proposed covers all the expected major atmospheric gases from e.g. H2O, CO2, CH4 NH3, HCN, H2S through to the more exotic metallic compounds, such as TiO, VO, and condensed species. Simulations of ARIEL performance in conducting exoplanet surveys have been performed – using conservative estimates of mission performance and a full model of all significant noise sources in the measurement – using a list of potential ARIEL targets that incorporates the latest available exoplanet statistics. The conclusion at the end of the Phase A study, is that ARIEL – in line with the stated mission objectives – will be able to observe about 1000 exoplanets depending on the details of the adopted survey strategy, thus confirming the feasibility of the main science objectives.Peer reviewedFinal Published versio
Analysis of shared common genetic risk between amyotrophic lateral sclerosis and epilepsy
Because hyper-excitability has been shown to be a shared pathophysiological mechanism, we used the latest and largest genome-wide studies in amyotrophic lateral sclerosis (n = 36,052) and epilepsy (n = 38,349) to determine genetic overlap between these conditions. First, we showed no significant genetic correlation, also when binned on minor allele frequency. Second, we confirmed the absence of polygenic overlap using genomic risk score analysis. Finally, we did not identify pleiotropic variants in meta-analyses of the 2 diseases. Our findings indicate that amyotrophic lateral sclerosis and epilepsy do not share common genetic risk, showing that hyper-excitability in both disorders has distinct origins
Genome-wide Analyses Identify KIF5A as a Novel ALS Gene
To identify novel genes associated with ALS, we undertook two lines of investigation. We carried out a genome-wide association study comparing 20,806 ALS cases and 59,804 controls. Independently, we performed a rare variant burden analysis comparing 1,138 index familial ALS cases and 19,494 controls. Through both approaches, we identified kinesin family member 5A (KIF5A) as a novel gene associated with ALS. Interestingly, mutations predominantly in the N-terminal motor domain of KIF5A are causative for two neurodegenerative diseases: hereditary spastic paraplegia (SPG10) and Charcot-Marie-Tooth type 2 (CMT2). In contrast, ALS-associated mutations are primarily located at the C-terminal cargo-binding tail domain and patients harboring loss-of-function mutations displayed an extended survival relative to typical ALS cases. Taken together, these results broaden the phenotype spectrum resulting from mutations in KIF5A and strengthen the role of cytoskeletal defects in the pathogenesis of ALS.Peer reviewe
Correction to: Two years later: Is the SARS-CoV-2 pandemic still having an impact on emergency surgery? An international cross-sectional survey among WSES members
Background: The SARS-CoV-2 pandemic is still ongoing and a major challenge for health care services worldwide. In the first WSES COVID-19 emergency surgery survey, a strong negative impact on emergency surgery (ES) had been described already early in the pandemic situation. However, the knowledge is limited about current effects of the pandemic on patient flow through emergency rooms, daily routine and decision making in ES as well as their changes over time during the last two pandemic years. This second WSES COVID-19 emergency surgery survey investigates the impact of the SARS-CoV-2 pandemic on ES during the course of the pandemic.
Methods: A web survey had been distributed to medical specialists in ES during a four-week period from January 2022, investigating the impact of the pandemic on patients and septic diseases both requiring ES, structural problems due to the pandemic and time-to-intervention in ES routine.
Results: 367 collaborators from 59 countries responded to the survey. The majority indicated that the pandemic still significantly impacts on treatment and outcome of surgical emergency patients (83.1% and 78.5%, respectively). As reasons, the collaborators reported decreased case load in ES (44.7%), but patients presenting with more prolonged and severe diseases, especially concerning perforated appendicitis (62.1%) and diverticulitis (57.5%). Otherwise, approximately 50% of the participants still observe a delay in time-to-intervention in ES compared with the situation before the pandemic. Relevant causes leading to enlarged time-to-intervention in ES during the pandemic are persistent problems with in-hospital logistics, lacks in medical staff as well as operating room and intensive care capacities during the pandemic. This leads not only to the need for triage or transferring of ES patients to other hospitals, reported by 64.0% and 48.8% of the collaborators, respectively, but also to paradigm shifts in treatment modalities to non-operative approaches reported by 67.3% of the participants, especially in uncomplicated appendicitis, cholecystitis and multiple-recurrent diverticulitis.
Conclusions: The SARS-CoV-2 pandemic still significantly impacts on care and outcome of patients in ES. Well-known problems with in-hospital logistics are not sufficiently resolved by now; however, medical staff shortages and reduced capacities have been dramatically aggravated over last two pandemic years
PHYSIOLOGICAL ANALYSIS OF YEAST SACCHAROMYCES CEREVISIAE CELLS BY FLOW CYTOMETRY DURING EXPOSURE TO FURFURAL, AN IMPORTANT FERMENTATION INHIBITOR
Saccharomyces cerevisiae is the preferred microorganism in the ethanol fermentation industry from
renewable resources such as lignocellulosic biomass. In the process of obtaining monomeric sugars
from lignocellulose trough a combination of physical, chemical and enzymatic treatments of biomass
formation of inhibitory compounds occurs among wich furfural is the most abundant (Almeida et al,
2007). S. cerevisiae is relatively tolerant to furfural because it is capable of converting it to the
corresponding alcohol with lower inhibitory capability by NAD(P)H dependent reactions
(Taherzadeh et al, 1999). Unfortunately these mechanisms of detoxification compete for key
enzymes and cofactors needed to bra nch carbon flow to respiration and to ethanol production.
Several studies have reported that furfural decreased yeast viability, specific growth rate and
volumetric fermentation rate. A recent work (Allen et al, 2010) has shown that furfural induced
reactive oxygen species (ROS) accumulation and cellular damage in S. cerevisiae. However the toxicity mechanism of furfural on yeast cells is not yet fully understood.
In our study we have conducted a flow cytometry analysis on yeast cells from CEN-PK family in
response to treatment with different concentrations of furfural. Exposure to high levels of inhibitor
did not caused ROS accumulation but resulted in increased intracellular depolarization and
accumulation of dead cells. These results may shed light on the mechanism of toxicity of furfural in
yeast and might be useful to improve the inhibitor resistance in S. cerevisiae
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