Neo-functionalization in Saccharomyces cerevisiae: a novel Nrg1-Rtg3 chimeric transcriptional modulator is essential to maintain mitochondrial DNA integrity.

In Saccharomyces cerevisiae, the transcriptional repressor Nrg1 (Negative Regulator of Glucose-repressed genes) and the ß-Zip transcription factor Rtg3 (ReTroGrade regulation) mediate glucose repression and signalling from the mitochondria to the nucleus, respectively. Here, we show a novel function of these two proteins, in which alanine promotes the formation of a chimeric Nrg1/Rtg3 regulator that represses the ALT2 gene (encoding an alanine transaminase paralog of unknown function). An NRG1/NRG2 paralogous pair, resulting from a post-wide genome small-scale duplication event, is present in the Saccharomyces genus. Neo-functionalization of only one paralog resulted in the ability of Nrg1 to interact with Rtg3. Both nrg1Δ and rtg3Δ single mutant strains were unable to use ethanol and showed a typical petite (small) phenotype on glucose. Neither of the wild-type genes complemented the petite phenotype, suggesting irreversible mitochondrial DNA damage in these mutants. Neither nrg1Δ nor rtg3Δ mutant strains expressed genes encoded by any of the five polycistronic units transcribed from mitochondrial DNA in S. cerevisiae. This, and the direct measurement of the mitochondrial DNA gene complement, confirmed that irreversible damage of the mitochondrial DNA occurred in both mutant strains, which is consistent with the essential role of the chimeric Nrg1/Rtg3 regulator in mitochondrial DNA maintenance.

The Use of Thioflavin T for the Estimation and Measurement of the Plasma Membrane Electric Potential Difference in Different Yeast Strains.

The use of the cationic, dye thioflavin T (ThT), to estimate the electric plasma membrane potential difference (PMP) via the fluorescence changes and to obtain its actual values from the accumulation of the dye, considering important correction factors by its binding to the internal components of the cell, was described previously for baker's yeast. However, it was considered important to explore whether the method developed could be applied to other yeast strains. Alternative ways to estimate the PMP by using flow cytometry and a multi-well plate reader are also presented here. The methods were tested with other strains of Saccharomyces cerevisiae (W303-1A and FY833), as well as with non-conventional yeasts: Debaryomyces hansenii, Candida albicans, Meyerozyma guilliermondii, and Rhodotorula mucilaginosa. Results of the estimation of the PMP via the fluorescence changes under different conditions were adequate with all strains. Consistent results were also obtained with several mutants of the main monovalent transporters, validating ThT as a monitor for PMP estimation.

[Relationship between the oxidative profile and the diet diversity index in older adults in an urban-marginal area of Costa Rica]. / Relación entre el perfil oxidativo y el índice de diversidad de la dieta en adultos mayores de una zona urbano-marginal de Costa Rica.

BACKGROUND AND OBJECTIVE: The older we get, the greater the production of reactive oxygen species and therefore the greater the oxidative stress, which is related to the deterioration of the health of older adults. This study analyzed the relationship between the oxidative profile and the dietary diversity index in an urban-marginal population of older adults in Costa Rica. METHODS: Eighty-eight older adults were studied and various markers of oxidative stress, serum glucose levels, lipid profile, and some micronutrients were determined. In addition, the body mass index (BMI) was calculated and the dietary diversity index (DDI) was determined. RESULTS: Lipid peroxidation and DNA oxidation, a mean plasma antioxidant capacity percentage of 39.54±10.67%, which decreased with age, were evidenced. 67% of the participants had alterations in glycemia, 73% had one or more alterations in blood lipid levels, 55% had insufficient vitamin D levels, and 68.6% were overweight. The average IDD was 4.91 points, indicating that the diet was not very diverse. No relationship was found between IDD and nutritional status, between nutritional status and oxidative stress, nor between biochemical variables and oxidative stress. CONCLUSION: The adults studied presented high oxidative stress, a high percentage of overweight, and a low IDD. A higher IDD was associated with a lower blood concentration of MDA and a higher % PAC.

Preliminary Analysis of Unsaturated Fatty Acid Profiles of Coffea arabica L., in Samples with a Denomination of Origin and Speciality of Oaxaca, Mexico.

In February 2020, Coffea arabica L. grown on the coast and in the Southern Sierra Madre of the state of Oaxaca, Mexico obtained the denomination of origin. Which does not have data on color and chemical composition, the first associated with the degree of roasting and the second with lipids (17-18%), as the group of compounds responsible, in part, for flavor, consistency, and may contribute to health benefits. In the present work, color was determined on the CIE L*a*b* scale and the unsaturated fatty acids by Nuclear Magnetic Resonance (NMR) of 1H and 13C in samples of medium roasted specialty coffee from the "Pluma" coffee-growing region, Oaxaca, Mexico. The average value of L* luminosity in ground coffee was 42.1 ± 0.1 reported for a light roast. Unsaturated fatty acids were quantified from the lipid fraction of the gr1 ound grain by NMR 1H and 13C, obtaining on average the highest abundance of linoleic (41.7 ± 0.5 by 1 H and 41.24 ± 0.5 by 13C), followed by oleic (9.2 ± 0.2 by 1H and 7.4 ± 0.2 by 13C) and linolenic (1.5 ± 0.1 by H and 1.1 ± 0.2 by 13C). This study indicates that 1H and 13C NMR spectroscopy is a useful tool for the quantification of linolenic, linoleic, and oleic fatty acids by the method of key signal shifts of these acids found in lipid samples in roasted coffee grains.

DhDIT2 Encodes a Debaryomyces hansenii Cytochrome P450 Involved in Benzo(a)pyrene Degradation-A Proposal for Mycoremediation.

Pollutants, such as polycyclic aromatic hydrocarbons (PAHs), e.g., benzo(a)pyrene (BaP), are common components of contaminating mixtures. Such compounds are ubiquitous, extremely toxic, and they pollute soils and aquatic niches. The need for new microorganism-based remediation strategies prompted researchers to identify the most suitable organisms to eliminate pollutants without interfering with the ecosystem. We analyzed the effect caused by BaP on the growth properties of Candida albicans, Debaryomyces hansenii, Rhodotorula mucilaginosa, and Saccharomyces cerevisiae. Their ability to metabolize BaP was also evaluated. The aim was to identify an optimal candidate to be used as the central component of a mycoremediation strategy. The results show that all four yeast species metabolized BaP by more than 70%, whereas their viability was not affected. The best results were observed for D. hansenii. When an incubation was performed in the presence of a cytochrome P450 (CYP) inhibitor, no BaP degradation was observed. Thus, the initial oxidation step is mediated by a CYP enzyme. Additionally, this study identified the D. hansenii DhDIT2 gene as essential to perform the initial degradation of BaP. Hence, we propose that D. hansenii and a S. cerevisiae expressing the DhDIT2 gene are suitable candidates to degrade BaP in contaminated environments.

Study of the mechanism of ε-poly-l-lysine as an antifungal on Candida albicans and Saccharomyces cerevisiae.

The antimicrobial activity of ε-poly-l-lysine (EPL) has been documented, but its antifungal activity on yeast is not well defined and its mechanism of action has been vaguely explained. Our studies revealed that on both, Candida albicans and Saccharomyces cerevisiae, the minimum inhibitory concentration (MIC) and the minimum fungicidal concentration (MFC) were 250 µg·mL-1; EPL produced a K+ and Ca2+ efflux, and at higher concentrations also an efflux of material absorbing at 260 nm, small peptides, and phosphate is produced, along with the inhibition of fermentation and extracellular acidification and respiration. Moreover, growth was inhibited, reactive oxygen species (ROS) production increased, and cell viability decreased. The polycation also produced plasma membrane potential hyperpolarization. The effects were dependent both on the cell quantity and polycation concentration, as well as the media used. The plasma membrane disruption was confirmed by TEM and PI staining.

Moderate exercise combined with metformin-treatment improves mitochondrial bioenergetics of the quadriceps muscle of old female Wistar rats.

Sarcopenia is a syndrome that leads to physical disability and that deteriorates elderly people´s life quality. The etiology of sarcopenia is multifactorial, but mitochondrial dysfunction plays a paramount role in this pathology. Our research group has shown that the combined treatment of metformin (MTF) and exercise has beneficial effects for preventing muscle loss and fat accumulation, by modulating the redox state. To get an insight into the mechanism of the combined treatment, the mitochondrial bioenergetics was studied in the mitochondria isolated from old female Wistar rats quadriceps muscles. The animals were divided into six groups; three performed exercise on a treadmill for 5 days/week for 20 months, and the other three were sedentary. Also, two groups of each were treated with MTF for 6 or 12 months. The rats were euthanized at 24 months. The mitochondria were isolated and supercomplexes formation along with oxygen consumption, ATP synthesis, and ROS generation were evaluated. Our results showed that the combined treatment for 12 months increased the complex I and IV activities associated with the supercomplexes, simultaneously, ATP synthesis increased while ROS production decreased, indicating a tightly coupled mitochondria. The role of exercise plus the MTF treatment against sarcopenia in old muscles is discussed.

Xylose and yeasts: A story beyond xylitol production.

Six different yeasts were used to study their metabolism of glucose and xylose, and mainly their capacity to produce ethanol and xylitol. The strains used were Candida guilliermondii, Debaryomyces hansenii, Saccharomyces cerevisiae, Kluyveromyces marxianus, Meyerozyma guilliermondii and Clavispora lusitaniae, four isolated from a rural mezcal fermentation facility. All of them produced ethanol when the substrate was glucose. When incubated in a medium containing xylose instead of glucose, only K. marxianus and M. guilliermondii were able to produce ethanol from xylose. On the other hand, all of them could produce some xylitol from xylose, but the most active in this regard were K. marxianus, M. guilliermondii, C. lusitaniae, and C. guilliermondii with the highest amount of xylitol produced. The capacity of all strains to take up glucose and xylose was also studied. Xylose, in different degrees, produced a redox imbalance in all yeasts. Respiration capacity was also studied with glucose or xylose, where C. guilliermondii, D. hansenii, K. marxianus and M. guilliermondii showed higher cyanide resistant respiration when grown in xylose. Neither xylose transport nor xylitol production were enhanced by an acidic environment (pH 4), which can be interpreted as the absence of a proton/sugar symporter mechanism for xylose transport, except for C. lusitaniae. The effects produced by xylose and their magnitude depend on the background of the studied yeast and the conditions in which these are studied.

The high osmolarity glycerol (HOG) pathway in fungi†.

While fungi are widely occupying nature, many species are responsible for devastating mycosis in humans. Such niche diversity explains how quick fungal adaptation is necessary to endow the capacity of withstanding fluctuating environments and to cope with host-imposed conditions. Among all the molecular mechanisms evolved by fungi, the most studied one is the activation of the phosphorelay signalling pathways, of which the high osmolarity glycerol (HOG) pathway constitutes one of the key molecular apparatus underpinning fungal adaptation and virulence. In this review, we summarize the seminal knowledge of the HOG pathway with its more recent developments. We specifically described the HOG-mediated stress adaptation, with a particular focus on osmotic and oxidative stress, and point out some lags in our understanding of its involvement in the virulence of pathogenic species including, the medically important fungi Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus, compared to the model yeast Saccharomyces cerevisiae. Finally, we also highlighted some possible applications of the HOG pathway modifications to improve the fungal-based production of natural products in the industry.

Sugar-Free Milk Chocolate as a Carrier of Omega-3 Polyunsaturated Fatty Acids and Probiotics: A Potential Functional Food for the Diabetic Population.

Chocolate is an adequate matrix to deliver bioactive ingredients. However, it contains high sugar levels, one of the leading causes of chronic degenerative diseases. This work aimed to evaluate the effects of milk chocolate reformulation with alternative sugar sweeteners (Sw; isomalt + stevia), probiotics (Prob), and ω-3 polyunsaturated fatty acids (PUFAs) on its physicochemical properties and consumers' acceptability. Lactobacillus plantarum 299v (L. p299v) and Lactobacillus acidophilus La3 (DSMZ 17742) were added as Prob strains, and fish oil (FO) was added as the source of ω-3 PUFAs. Prob addition resulted in chocolates with >2 × 107 colony forming unit (CFU) per serving size (12 g). Except for Prob, aw values of all treatments were <0.46. Sw and Sw + Prob presented the nearest values to the control in hardness, whereas Sw without FO increased fracturability. FO, Sw + FO, and Sw + Prob + FO contained 107.4 ± 12.84, 142.9 ± 17.9, and 133.78 ± 8.76 mg of ω-3 PUFAs per chocolate, respectively. Prob + FO increased the resistance of chocolate to shear stress, while Sw + FO showed a similar flow behavior to the control. The consumers' acceptability of Sw + Prob chocolate was adequate, while Sw + Prob + FO had higher acceptability than Prob + FO. Health benefits of reformulated milk chocolates requires further assessment by in vitro, in vivo and clinical studies.

Osmolyte Signatures for the Protection of Aspergillus sydowii Cells under Halophilic Conditions and Osmotic Shock.

Aspergillus sydowii is a moderate halophile fungus extensively studied for its biotechnological potential and halophile responses, which has also been reported as a coral reef pathogen. In a recent publication, the transcriptomic analysis of this fungus, when growing on wheat straw, showed that genes related to cell wall modification and cation transporters were upregulated under hypersaline conditions but not under 0.5 M NaCl, the optimal salinity for growth in this strain. This led us to study osmolyte accumulation as a mechanism to withstand moderate salinity. In this work, we show that A. sydowii accumulates trehalose, arabitol, mannitol, and glycerol with different temporal dynamics, which depend on whether the fungus is exposed to hypo- or hyperosmotic stress. The transcripts coding for enzymes responsible for polyalcohol synthesis were regulated in a stress-dependent manner. Interestingly, A. sydowii contains three homologs (Hog1, Hog2 and MpkC) of the Hog1 MAPK, the master regulator of hyperosmotic stress response in S. cerevisiae and other fungi. We show a differential regulation of these MAPKs under different salinity conditions, including sustained basal Hog1/Hog2 phosphorylation levels in the absence of NaCl or in the presence of 2.0 M NaCl, in contrast to what is observed in S. cerevisiae. These findings indicate that halophilic fungi such as A. sydowii utilize different osmoadaptation mechanisms to hypersaline conditions.

The pest kill rate of thirteen natural enemies as aggregate evaluation criterion of their biological control potential of Tuta absoluta.

Ecologists study how populations are regulated, while scientists studying biological pest control apply population regulation processes to reduce numbers of harmful organisms: an organism (a natural enemy) is used to reduce the population density of another organism (a pest). Finding an effective biological control agent among the tens to hundreds of natural enemies of a pest is a daunting task. Evaluation criteria help in a first selection to remove clearly ineffective or risky species from the list of candidates. Next, we propose to use an aggregate evaluation criterion, the pest kill rate, to compare the pest population reduction capacity of species not eliminated during the first selection. The pest kill rate is the average daily lifetime killing of the pest by the natural enemy under consideration. Pest kill rates of six species of predators and seven species of parasitoids of Tuta absoluta were calculated and compared. Several natural enemies had pest kill rates that were too low to be able to theoretically reduce the pest population below crop damaging densities. Other species showed a high pest reduction capacity and their potential for practical application can now be tested under commercial crop production conditions.

Chemical Characterization of Plant Extracts and Evaluation of their Nematicidal and Phytotoxic Potential.

Nacobbus aberrans ranks among the "top ten" plant-parasitic nematodes of phytosanitary importance. It causes significant losses in commercial interest crops in America and is a potential risk in the European Union. The nematicidal and phytotoxic activities of seven plant extracts against N. aberrans and Solanum lycopersicum were evaluated in vitro, respectively. The chemical nature of three nematicidal extracts (EC50,48h ≤ 113 µg mL-1) was studied through NMR analysis. Plant extracts showed nematicidal activity on second-stage juveniles (J2): (≥87%) at 1000 µg mL-1 after 72 h, and their EC50 values were 71.4-468.1 and 31.5-299.8 µg mL-1 after 24 and 48 h, respectively. Extracts with the best nematicidal potential (EC50,48h < 113 µg mL-1) were those from Adenophyllum aurantium, Alloispermum integrifolium, and Tournefortia densiflora, which inhibited L. esculentum seed growth by 100% at 20 µg mL-1. Stigmasterol (1), ß-sitosterol (2), and α-terthienyl (3) were identified from A. aurantium, while 1, 2, lutein (4), centaurin (5), patuletin-7-ß-O-glucoside (6), pendulin (7), and penduletin (8) were identified from A. integrifolium. From T. densiflora extract, allantoin (9), 9-O-angeloyl-retronecine (10), and its N-oxide (11) were identified. The present research is the first to report the effect of T. densiflora, A. integrifolium, and A. aurantium against N. aberrans and chemically characterized nematicidal extracts that may provide alternative sources of botanical nematicides.

Physicochemical Properties and Sensory Acceptability of a Next-Generation Functional Chocolate Added with Omega-3 Polyunsaturated Fatty Acids and Probiotics.

In this study, a milk chocolate formulation was developed to serve as vehicle of Omega-3 (ω3) polyunsaturated fatty acids (PUFAs) and probiotics (L. plantarum 299v and L. rhamnosus GG). Fish oil (FO) was incorporated in chocolate as a source of ω3 PUFAs. Probiotics (Prob) and FO were added during tempering, obtaining chocolates with 76.0 ± 5.2 mg (FO1) or 195.8 ± 6.5 mg (FO2) of ω3 PUFAs, and >1 × 106 CFU of Prob per chocolate portion (12 g). The physicochemical properties (rheological analysis, texture, surface instrumental color, aw, and fatty acid profile), and sensory acceptability of the formulations were determined. Prob and FO generated a decrease in L* and white index (WI) values. Except for Prob + FO2, all treatments showed a decrease in aw. Rheological parameters of FO1 and Prob + FO1 presented the most similar behavior as compared with the control. Prob or FO1 addition did not affect the overall consumer's acceptability of chocolate; and when both nutraceuticals were combined (Prob + FO1) the product showed adequate overall acceptability. FO2 formulations were not considered adequate to maintain physicochemical properties and sensory acceptability of chocolate. Results indicated that milk chocolate is a suitable vehicle for delivering ω3 PUFAs and Prob, which are essential to enhance cognitive development in children.

Origin, structural characteristics, prevention measures, diagnosis and potential drugs to prevent and COVID-19. / Origen, características estructurales, medidas de prevención, diagnóstico y fármacos potenciales para prevenir y controlar COVID-19.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) causes COVID-19 (Coronavirus disease 2019). This disease was detected in the city of Wuhan in China in December 2019. People infected with COVID-19 shows varying manifestations, depending on their health and age. The most common symptoms are fever, cough, myalgia, fatigue, odynophagia, and dyspnea. Infected adults older 60 years of age are the group of patients most susceptible to severe COVID-19 states and present comor-bidity in the presence of chronic diseases. On the other hand, it is also essential to have tests to detect SARS-COV-2 in people and follow the evolution of COVID-19 quickly, reliably, and cheap. To achieve this, there are real-time reverse transcription pol-ymerase chain reaction (RT-PCR) tests, isothermal nucleic acid amplification, and enzyme immunostimulation. Currently, there are no drug treatments to prevent infection and to combat the virus's effects. However, different research groups that are conduct-ing in vitro, in vivo, and in silico tests to find drugs able to provide an immune response and to control infection in humans with SARS-CoV-2. Chloroquine, hydroxychloroquine, remdesivir, interferon-2b, and oseltamivir are some pharmacological options evaluated in clinical trials for prophylaxis of COVID-19. The purpose of this review is to establish a reference framework for taxonomic classification of SARS-CoV-2 and the relationship they have with other CoVs, as well as their structure and propaga-tion pathways in humans. The characteristics and symptoms presented by patients with COVID-19, the detection methods, and possible treatments are also presented.

El síndrome respiratorio agudo severo coronavirus 2 (SARS-CoV-2) es responsable de la enfermedad denominada COVID-19 (acrónimo del inglés Coronavirus Disease-2019). Esta enfermedad fue detectada inicialmente en la ciudad de Wuhan, China en diciembre de 2019. Las personas contagiadas con COVID-19 presentan síntomas variados, dependiendo de su estado de salud y edad. Los síntomas más comunes son fiebre, tos, mialgia, fatiga, odinofagia y disnea. También se ha observado que en algunos pacientes, la infección es asintomática. Los adultos mayores de 60 años infectados son el grupo de pacientes más susceptibles a desarrollar estados severos de COVID-19 y se presenta comorbilidad en presencia de enfermedades crónicas. Por otra parte, también es importante disponer de pruebas que permitan detectar al SARS-COV-2 y seguir la evolución de COVID-19 de forma rápida, confiable y barata. Para lograr esto, existen pruebas de reacción en cadena de la polimerasa de transcripción inversa en tiempo real (RT-PCR), de amplificación isotérmica de ácido nucleico y de inmunoestimulación enzimática. Actualmente, no existen tratamientos para la prevención del contagio y combatir los efectos del virus en la salud humana. Sin embargo, en el mundo hay grupos de investigación que están realizando pruebas in vitro, in vivo e in silico para encontrar fármacos que sean capaces de prevenir y/o controlar la infección en humanos con SARS-CoV-2. La cloroquina, hidroxicloroquina, remdesivir, interferon-2b y oseltamivir son algunas de las opciones farmacológicas que están siendo evaluadas en pruebas clínicas para la profilaxis de COVID-19. El objetivo de la presente revisión consiste en establecer un marco de referencia de la clasificación taxonómica del SARS-CoV-2 y la relación que guardan con otros coronavirus, así como su estructura y forma de propagarse en el ser humano. También se presentan las características y síntomas de pacientes con COVID-19, los métodos de detección y potenciales tratamientos.

Characterization of pectin extracted under mild conditions from tempesquistle (Sideroxylon palmeri) fruit at two maturity stages.

BACKGROUND: le tree (Sideroxylon palmeri) belongs to family Sapotaceae, and its fruits contain hydrophilic and hydrophobic gums. Aim of this study was to develop an extraction method for pectin, a hydrophilic gum, from green and ripe tempesquistle fruit. The extraction method was gentle to minimize potential structural changes in pectin, a maceration was used, and then pectin precipitation was induced with acetone at room temperature. Pectin characterization was carried out in two steps. The first step consisted of qualitative tests of Molisch, Fehling and Lugol. The second step consisted of quantitative tests to determine esterification degree (ED) by ATR-FTIR and D-galacturonic acid (D-GalA) content with a colorimetric assay. ATR-FTIR spectroscopic method revealed that green and ripe tempesquistle fruit have an ED of 0% and 30.4%, respectively. Both fruit have a low ED pectin. The content of D-GalA in green and ripe pectins was 18.8 ±2.7% and 20.2 ±0.6%, respectively. The yield obtained in green and ripe fruit samples was 1.6 ±0.2% and 3.0 ±0.1%, respectively. The extraction method allowed two types of pectins obtained in function of maturity stage of tempesquistle fruit distinguishable by. METHODS: istle tree (Sideroxylon palmeri) belongs to family Sapotaceae, and its fruits contain hydrophilic and hydrophobic gums. Aim of this study was to develop an extraction method for pectin, a hydrophilic gum, from green and ripe tempesquistle fruit. The extraction method was gentle to minimize potential structural changes in pectin, a maceration was used, and then pectin precipitation was induced with acetone at room temperature. Pectin characterization was carried out in two steps. The first step consisted of qualitative tests of Molisch, Fehling and Lugol. The second step consisted of quantitative tests to determine esterification degree (ED) by ATR-FTIR and D-galacturonic acid (D-GalA) content with a colorimetric assay. ATR-FTIR spectroscopic method revealed that green and ripe tempesquistle fruit have an ED of 0% and 30.4%, respectively. Both fruit have a low ED pectin. The content of D-GalA in green and ripe pectins was 18.8 ±2.7% and 20.2 ±0.6%, respectively. The yield obtained in green and ripe fruit samples was 1.6 ±0.2% and 3.0 ±0.1%, respectively. The extraction method allowed two types of pectins obtained in function of maturity stage of tempesquistle fruit distinguishable by ATR. RESULTS: istle tree (Sideroxylon palmeri) belongs to family Sapotaceae, and its fruits contain hydrophilic and hydrophobic gums. Aim of this study was to develop an extraction method for pectin, a hydrophilic gum, from green and ripe tempesquistle fruit. The extraction method was gentle to minimize potential structural changes in pectin, a maceration was used, and then pectin precipitation was induced with acetone at room temperature. Pectin characterization was carried out in two steps. The first step consisted of qualitative tests of Molisch, Fehling and Lugol. The second step consisted of quantitative tests to determine esterification degree (ED) by ATR-FTIR and D-galacturonic acid (D-GalA) content with a colorimetric assay. ATR-FTIR spectroscopic method revealed that green and ripe tempesquistle fruit have an ED of 0% and 30.4%, respectively. Both fruit have a low ED pectin. The content of D-GalA in green and ripe pectins was 18.8 ±2.7% and 20.2 ±0.6%, respectively. The yield obtained in green and ripe fruit samples was 1.6 ±0.2% and 3.0 ±0.1%, respectively. The extraction method allowed two types of pectins obtained in function of maturity stage of tempesquistle fruit distinguishable by ATR-FTIR.

Contribution of the mitogen-activated protein kinase Hog1 to the halotolerance of the marine yeast Debaryomyces hansenii.

Halotolerant species are adapted to dealing continually with hyperosmotic environments, having evolved strategies that are uncommon in other organisms. The HOG pathway is the master system that regulates the cellular adaptation under these conditions; nevertheless, apart from the importance of Debaryomyces hansenii as an organism representative of the halotolerant class, its HOG1 pathway has been poorly studied, due to the difficulty of applying conventional recombinant DNA technology. Here we describe for the first time the phenotypic characterisation of a null HOG1 mutant of D. hansenii. Dhhog1Δ strain was found moderately resistant to 1 M NaCl and sensitive to higher concentrations. Under hyperosmotic shock, DhHog1 fully upregulated transcription of DhSTL1 and partially upregulated that of DhGPD1. High osmotic stress lead to long-term inner glycerol accumulation that was partially dependent on DhHog1. These observations indicated that the HOG pathway is required for survival under high external osmolarity but dispensable under low and mid-osmotic conditions. It was also found that DhHog1 can regulate response to alkali stress during hyperosmotic conditions and that it plays a role in oxidative and endoplasmic reticulum stress. Taken together, these results provide new insight into the contribution of this MAPK in halotolerance of this yeast.

Origen, características estructurales, medidas de prevención, diagnóstico y fármacos potenciales para prevenir y controlar COVID-19 / Origin, structural characteristics, prevention measures, diagnosis and potential drugs to prevent and COVID-19

El síndrome respiratorio agudo severo coronavirus 2 (SARS-CoV-2) es responsable de la enfermedad denominada COVID-19 (acrónimo del inglés Coronavirus Disease-2019). Esta enfermedad fue detectada inicialmente en la ciudad de Wuhan, China en diciembre de 2019. Las personas contagiadas con COVID-19 presentan síntomas variados, dependiendo de su estado de salud y edad. Los síntomas más comunes son fiebre, tos, mialgia, fatiga, odinofagia y disnea. También se ha observado que en algunos pacientes, la infección es asintomática. Los adultos mayores de 60 años infectados son el grupo de pacientes más susceptibles a desarrollar estados severos de COVID-19 y se presenta comorbilidad en presencia de enfermedades crónicas. Por otra parte, también es importante disponer de pruebas que permitan detectar al SARS-COV-2 y seguir la evolución de COVID-19 de forma rápida, confiable y barata. Para lograr esto, existen pruebas de reacción en cadena de la polimerasa de transcripción inversa en tiempo real (RT-PCR), de amplificación isotérmica de ácido nucleico y de inmunoestimulación enzimática. Actualmente, no existen tratamientos para la prevención del contagio y combatir los efectos del virus en la salud humana. Sin embargo, en el mundo hay grupos de investigación que están realizando pruebas in vitro, in vivo e in silico para encontrar fármacos que sean capaces de prevenir y/o controlar la infección en humanos con SARS-CoV-2. La cloroquina, hidroxicloroquina, remdesivir, interferon-2b y oseltamivir son algunas de las opciones farmacológicas que están siendo evaluadas en pruebas clínicas para la profilaxis de COVID-19. El objetivo de la presente revisión consiste en establecer un marco de referencia de la clasificación taxonómica del SARS-CoV-2 y la relación que guardan con otros coronavirus, así como su estructura y forma de propagarse en el ser humano. También se presentan las características y síntomas de pacientes con COVID-19, los métodos de detección y potenciales tratamientos.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) causes COVID-19 (Coronavirus disease 2019). This disease was detected in the city of Wuhan in China in December 2019. People infected with COVID-19 shows varying manifestations, depending on their health and age. The most common symptoms are fever, cough, myalgia, fatigue, odynophagia, and dyspnea. Infected adults older 60 years of age are the group of patients most susceptible to severe COVID-19 states and present comor-bidity in the presence of chronic diseases. On the other hand, it is also essential to have tests to detect SARS-COV-2 in people and follow the evolution of COVID-19 quickly, reliably, and cheap. To achieve this, there are real-time reverse transcription pol-ymerase chain reaction (RT-PCR) tests, isothermal nucleic acid amplification, and enzyme immunostimulation. Currently, there are no drug treatments to prevent infection and to combat the virus's effects. However, different research groups that are conduct-ing in vitro, in vivo, and in silico tests to find drugs able to provide an immune response and to control infection in humans with SARS-CoV-2. Chloroquine, hydroxychloroquine, remdesivir, interferon-2b, and oseltamivir are some pharmacological options evaluated in clinical trials for prophylaxis of COVID-19. The purpose of this review is to establish a reference framework for taxonomic classification of SARS-CoV-2 and the relationship they have with other CoVs, as well as their structure and propaga-tion pathways in humans. The characteristics and symptoms presented by patients with COVID-19, the detection methods, and possible treatments are also presented.

Retraction Note to: Acridine yellow. A novel use to estimate and measure the plasma membrane potential in Saccharomyces cerevisiae.

The authors have retracted this article [1]. After publication the dye used in this study was analysed by NMR and mass spectroscopy and found not to be acridine yellow, but rather, was identified as thioflavin T.

Salinity and high pH affect energy pathways and growth in Debaryomyces hansenii.

The physiological behavior of Debaryomyces hansenii in response to saline stress and elevated pH was studied. The combination of 1 M NaCl salt and pH 8.0 was required to produce significant changes in the lag phase of growth and a consequent effect on viability. pH 8.0 in the absence or presence of 1 M NaCl produced changes in physiological functions such as respiration, acidification, rubidium transport, transmembrane potential, and fermentation. Our data indicated a stimulation of the H+-ATPase of the plasma membrane at pH 8.0, which increased the transmembrane potential and favored the entry of Na+; this effect was intensified in the presence of NaCl, so the increased energy expenditure resulting from H+ pumping and the extrusion of excess Na+ affected viability. The gene expression pattern studied by microarrays of cells incubated under saline conditions and high pH revealed a down-regulation in genes related to energy-producing pathways and in some genes involved in the cell cycle and DNA transcription, confirming our experimental hypothesis. Although D. hansenii can tolerate high pH and high salt concentrations, its physiological behavior, is better at pH 6.0 and in the absence of sodium; thus, it is an alkali-halotolerant yeast and not a halophilic yeast as previously proposed by other authors.