RESUMO
Dietary acid load (DAL) is recognized as a risk factor for several chronic disorders, including obesity, diabetes, and osteoporosis. Recent evidence suggests that an elevated DAL, as measured by the validated potential renal acid load (PRAL) and net endogenous acid production (NEAP) scores, could also increase the risk for several cancers. This narrative review summarizes the potential role of DAL in Uruguayan cancer patients and outlines the potentially involved pathophysiological pathways that mediate the role of DAL in both cancer development and growth. Although Uruguay is a developing country, its average diet is a heavily meat-based Western one, translating into a supraphysiological acid burden from diet. In recent years, we have published epidemiologic evidence based on ten case-control studies involving 3736 cancer cases and 9534 hospital-based controls. Odds ratios and 95% confidence intervals were estimated for each interest variable to analyze the association between the exposure levels of DAL scores and cancer, calculated by unconditional logistic regression. In a majority of the cases, the highest DAL scores tended to double the cancer risk as compared to the lowest category. We also found high risks for methionine intake, an acidifying amino acid found in higher concentrations in animal-based foods, which may increase cancer risks at least by a joint action based on the pH and the proliferation enhancing properties of the amino acid itself.
Assuntos
Dieta , Neoplasias , Animais , Uruguai/epidemiologia , Dieta/efeitos adversos , Fatores de Risco , Obesidade/etiologia , Ácidos/metabolismo , Aminoácidos , Neoplasias/etiologia , Neoplasias/complicaçõesRESUMO
Hop bitter acids are used in the brewing industry to give beer bitterness. However, much of this bitterness is lost during processing, specifically during the wort boiling step. One of the major causes might be the interaction with protein-protein complexes. Therefore, the aim of this study was to clarify the role of hop bitter acids in protein aggregate formation using a proteomic approach. The effect of hop addition on protein composition was analyzed by liquid chromatography-mass spectrometry/MS (LC-MS/MS), and further analyses were performed to characterize the wort before and after boiling. Addition of hop bitter acids yielded a change in wort protein profiles, and hop bitter acids were found to bind primarily to less abundant proteins which are not related to beer quality traits, such as foam or haze. Wort protein aggregate profiles were revealed, and findings from this study suggested the precipitation of particular proteins in the aggregates during boiling when hops were added.
Assuntos
Humulus , Humulus/metabolismo , Agregados Proteicos , Cromatografia Líquida , Proteômica , Espectrometria de Massas em Tandem , Ácidos/metabolismoRESUMO
BACKGROUND: A high dietary acid load (DAL) can produce metabolic acidosis, which is linked to cancer development through mechanisms of inflammation and cell transformation. There is limited epidemiological evidence linking DAL and cancer risk; however, none of the published studies focused on DAL and esophageal cancer (EC) risk in particular. Therefore, we sought to explore this association in the present study. METHODS: A case-control study was performed in 1295 male patients (185 squamous cell EC cases and 1110 age-frequency and urban/rural residence matched controls) through a multitopic inquiry, including a food frequency questionnaire. Food-derived nutrients were calculated from available databases. The DAL was calculated based on two validated measures: Potential renal acid load (PRAL) score and net endogenous acid production (NEAP) score. Odds ratios (OR) and their 95% confidence intervals (95% CI) were estimated by unconditional logistic regression, adjusting for confounders. RESULTS: We found direct, significant associations between dietary acid load and EC risk: (OR = 2.28, 95% CI: 1.44-3.61, ptrend <0.0001) and (OR = 2.17, 95% CI: 1.38-3.41, ptrend <0.0001) for highest PRAL and NEAP tertiles, respectively. Our data raise the possibility that a high DAL may contribute to EC development. Both acid load scores were directly associated with animal-based foods (mainly meat) and inversely associated with the intake of plant-based foods. CONCLUSION: To the best of our knowledge, this is the first epidemiological case-control study analyzing associations of DAL and squamous cell EC risk. Further research is warranted to confirm our findings.
Assuntos
Dieta , Neoplasias Esofágicas , Ácidos/efeitos adversos , Ácidos/metabolismo , Animais , Estudos de Casos e Controles , Dieta/efeitos adversos , Neoplasias Esofágicas/epidemiologia , Neoplasias Esofágicas/etiologia , Humanos , Fatores de RiscoRESUMO
The cambuci is a native Brazilian fruit from the Atlantic Forest biome. A soft and astringent pulp, a green color, and a sweet aroma are its main characteristics. Classical food quality attributes (fresh fruit mass, fruit height, diameters, total soluble solid, titratable acidity, and ratio) and the metabolic profile from ten accessions from three different locations were analyzed herein by analytical methods (refractometry and neutralization titration) and nuclear magnetic resonance spectroscopy. Concerning sugar content, sucrose was the predominant compound, with glucose and fructose alternating in second, depending on the accession. Citric acid was the most relevant acid, followed by shikimic and quinic acids in quite variable amounts. These three main acids vary in amounts for each accession. Ascorbic acid content emerges as an important quality attribute and makes this fruit nutritionally attractive, due to values comparable to those contained in citric fruits. The main amino acids identified in cambuci were glutamic acid individually or in comprising the tripeptide glutathione (glutamic acid, cysteine, glycine). The quality diversity of the evaluated accessions suggests the potentiality of cambuci use in future breeding programs.
Assuntos
Frutas/química , Frutas/metabolismo , Myrtaceae/metabolismo , Ácidos/metabolismo , Antioxidantes/análise , Ácido Ascórbico/análise , Brasil , Carboidratos/análise , Qualidade dos Alimentos , Frutose/metabolismo , Glucose/metabolismo , Metaboloma , Metabolômica/métodos , Floresta ÚmidaRESUMO
In the actual mining scenario, copper bioleaching, mainly raw mined material known as run-of-mine (ROM) copper bioleaching, is the best alternative for the treatment of marginal resources that are not currently considered part of the profitable reserves because of the cost associated with leading technologies in copper extraction. It is foreseen that bioleaching will play a complementary role in either concentration-as it does in Minera Escondida Ltd. (MEL)-or chloride main leaching plants. In that way, it will be possible to maximize mines with installed solvent-extraction and electrowinning capacities that have not been operative since the depletion of their oxide ores. One of the main obstacles for widening bioleaching technology applications is the lack of knowledge about the key events and the attributes of the technology's critical events at the industrial level and mainly in ROM copper bioleaching industrial operations. It is relevant to assess the bed environment where the bacteria-mineral interaction occurs to learn about the limiting factors determining the leaching rate. Thus, due to inability to accurately determine in-situ key variables, their indirect assessment was evaluated by quantifying microbial metabolic-associated responses. Several candidate marker genes were selected to represent the predominant components of the microbial community inhabiting the industrial heap and the metabolisms involved in microbial responses to changes in the heap environment that affect the process performance. The microbial community's predominant components were Acidithiobacillus ferrooxidans, At. thiooxidans, Leptospirillum ferriphilum, and Sulfobacillus sp. Oxygen reduction, CO2 and N2 fixation/uptake, iron and sulfur oxidation, and response to osmotic stress were the metabolisms selected regarding research results previously reported in the system. After that, qPCR primers for each candidate gene were designed and validated. The expression profile of the selected genes vs. environmental key variables in pure cultures, column-leaching tests, and the industrial bioleaching heap was defined. We presented the results obtained from the industrial validation of the marker genes selected for assessing CO2 and N2 availability, osmotic stress response, as well as ferrous iron and sulfur oxidation activity in the bioleaching heap process of MEL. We demonstrated that molecular markers are useful for assessing limiting factors like nutrients and air supply, and the impact of the quality of recycled solutions. We also learned about the attributes of variables like CO2, ammonium, and sulfate levels that affect the industrial ROM-scale operation.
Assuntos
Acidithiobacillus/metabolismo , Ácidos/metabolismo , Bactérias/metabolismo , Biomarcadores/metabolismo , Cobre/metabolismo , Microbiologia Industrial/métodos , Laboratórios/normas , Acidithiobacillus/crescimento & desenvolvimento , Acidithiobacillus/isolamento & purificação , Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Biodiversidade , Cobre/isolamento & purificaçãoRESUMO
Yeast biomass is recycled in the process of bioethanol production using treatment with dilute sulphuric acid to control the bacterial population. This treatment can lead to loss of cell viability, with consequences on the fermentation yield. Thus, the aim of this study was to define the functional cellular responses to inorganic acid stress. Saccharomyces cerevisiae strains with mutation in several signalling pathways, as well as cells expressing pH-sensitive GFP derivative ratiometric pHluorin, were tested for cell survival and cytosolic pH (pHc) variation during exposure to low external pH (pHex). Mutants in calcium signalling and proton extrusion were transiently sensitive to low pHex, while the CWI slt2Δ mutant lost viability. Rescue of this mutant was observed when cells were exposed to extreme low pHex or glucose starvation and was dependent on the induced reduction of pHc. Therefore, a lowered pHc leads to a complete growth arrest, which protects the cells from lethal stress and keeps cells alive. Cytosolic pH is thus a signal that directs the growth stress-tolerance trade-off in yeast. A regulatory model was proposed to explain this mechanism, indicating the impairment of glucan synthesis as the primary cause of low pHex sensitivity.
Assuntos
Ácidos/metabolismo , Saccharomyces cerevisiae/genética , Estresse Fisiológico/genética , Ácidos Sulfúricos/metabolismo , Ácidos/efeitos adversos , Sinalização do Cálcio/genética , Metabolismo dos Carboidratos/genética , Sobrevivência Celular/genética , Parede Celular/metabolismo , Citosol/metabolismo , Etanol/metabolismo , Fermentação/genética , Concentração de Íons de Hidrogênio , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Transdução de Sinais/genética , Ácidos Sulfúricos/efeitos adversosRESUMO
Organisms that thrive in extremely acidic environments (≤pH 3.5) are of widespread importance in industrial applications, environmental issues, and evolutionary studies. Leptospirillum spp. constitute the only extremely acidophilic microbes in the phylogenetically deep-rooted bacterial phylum Nitrospirae. Leptospirilli are Gram-negative, obligatory chemolithoautotrophic, aerobic, ferrous iron oxidizers. This paper predicts genes that Leptospirilli use to survive at low pH and infers their evolutionary trajectory. Phylogenetic and other bioinformatic approaches suggest that these genes can be classified into (i) "first line of defense", involved in the prevention of the entry of protons into the cell, and (ii) neutralization or expulsion of protons that enter the cell. The first line of defense includes potassium transporters, predicted to form an inside positive membrane potential, spermidines, hopanoids, and Slps (starvation-inducible outer membrane proteins). The "second line of defense" includes proton pumps and enzymes that consume protons. Maximum parsimony, clustering methods, and gene alignments are used to infer the evolutionary trajectory that potentially enabled the ancestral Leptospirillum to transition from a postulated circum-neutral pH environment to an extremely acidic one. The hypothesized trajectory includes gene gains/loss events driven extensively by horizontal gene transfer, gene duplications, gene mutations, and genomic rearrangements.
Assuntos
Ácidos/toxicidade , Bactérias/genética , Genoma Bacteriano/genética , Genômica , Ácidos/metabolismo , Bactérias/metabolismo , Compostos Férricos/metabolismo , Transferência Genética Horizontal/genética , Genoma Bacteriano/efeitos dos fármacos , Concentração de Íons de Hidrogênio , Ferro/metabolismo , FilogeniaRESUMO
The virulence genes of Salmonella are modulated during infection by several regulatory systems, and the RcsCDB system is one of the most important of these. The S. Typhimurium EG14873 (rcsC11) strain harbours the rcsC11 point mutation, displaying a constitutive activation of this system, which is characterized by mucoid colonies and attenuated virulence phenotypes. In this work, the stability of the rcsC11 mutation was analysed under stress conditions. Under acid and anaerobic stresses, we observed the appearance of small and non-mucoid colonies of the rcsC11 strain. The sequencing of the rcsC gene from these colonies showed that the mutation is conserved. Moreover, we found that small colonies were also generated when the wild-type strain grew in acid and anaerobic conditions. It is worth noting that the transition from normal to atypical colonies of both strains only took place after several days of incubation and was not observed during eukaryotic cell infection. Therefore, the appearance of these atypical colonies is a characteristic feature of S. Typhimurium strains under stressful situations and does not involve a reversion of the rcsC11 allele and nor does it imply any risk to mammalian cells. Therefore, we propose that the S. Typhimurium rcsC11 strain is a good candidate for the development of attenuated vaccines.
Assuntos
Proteínas de Bactérias/genética , Mutação , Salmonella typhimurium/fisiologia , Estresse Fisiológico , Ácidos/metabolismo , Anaerobiose , Animais , Camundongos , Fenótipo , Células RAW 264.7 , Salmonella typhimurium/genética , Salmonella typhimurium/crescimento & desenvolvimento , Salmonella typhimurium/patogenicidade , Vacinas Atenuadas/genética , Virulência/genéticaRESUMO
Fossil fuels consumption impacts the greenhouse gas emissions. Biofuels are considered as alternative renewable energy sources to reduce the fossil fuels dependency. Bioethanol produced by recombinant microorganisms is a widely suggested alternative to increase the yield in fermentation processes. However, ethanol and acetate accumulation under the fermentation process had been described as important stressors for the metabolic capabilities of the microorganisms, stopping the fermentation process and affecting the ethanol yield. Ethanol tolerance is a determining factor in the improvement of fermentative properties of microorganisms; however understanding of ethanol tolerance is limited. The engineered Escherichia coli KO11 strain has been studied in detail and used as an ethanologenic bacteria model. The strain is capable of using glucose and xylose for an efficient ethanol yield. In the current work, the effect of the iron-sulfur cluster (ISC) over-expression in the KO11 strain, on its tolerance and ethanol yield, was evaluated. Fatty acids profiles of membrane phospholipids in the E. coli KO11 were modified under ethanol addition, but not due to the hscA mutation. The hscA mutation provoked a decrease in ethanol tolerance in the Kmp strain when was grown with 2% ethanol, in comparison to KO11 parent strain. Ethanol tolerance was improved in the mutant Kmp complemented with the recombinant isc gene cluster (pJC10 plasmid) from LD50 2.16% to LD50 3.8% ethanol. In batch fermentation on 1 L bioreactor using mineral medium with glucose (120 g/L), the KO11 strain showed ethanol production efficiencies of ~ 76.9%, while the hscA mutant (Kmp) ~ 75.4% and the transformed strain Kmp(pJC10) showed ~ 92.4% efficiency. Ethanol amount increase in the engineered Kmp(pJC10) strain was correlated with less organic acids (such as acetate and lactate) production in the fermentation medium (2.3 g/L), compared to that in the KO11 (17.05 g/L) and the Kmp (16.62 g/L). Alcohol dehydrogenase (ADH) activity was increased ~ 350% in the transformed Kmp(pJC10) strain, whereas in the Kmp mutant, the phosphoglycerate kinase (PGK), pyruvate kinase (PYK), and ADH activities were diminished, comparing to KO11. The results suggest that the isc system over-expression in the ethanologenic E. coli KO11 strain, increases ethanol yield mainly by improving ethanol tolerance and ADH activity, and by redirecting the metabolic flux from acetate synthesis to ethanol.
Assuntos
Ácidos/metabolismo , Tolerância a Medicamentos/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Etanol/metabolismo , Regulação Bacteriana da Expressão Gênica/genética , Família Multigênica/genética , Álcool Desidrogenase/genética , Técnicas de Cultura Celular por Lotes , Biocombustíveis , Reatores Biológicos , Escherichia coli/efeitos dos fármacos , Proteínas de Escherichia coli/genética , Etanol/toxicidade , Ácidos Graxos/análise , Ácidos Graxos/metabolismo , Fermentação , Engenharia Genética , Glucose/metabolismo , Proteínas de Choque Térmico HSP70/genética , Proteínas Ferro-Enxofre/genética , Cinética , Redes e Vias Metabólicas/genética , Mutação , Xilose/metabolismoRESUMO
There is growing evidence that C. albicans is associated with dental caries, but its role on caries development needs to be better clarified. Label="OBJECTIVE">To evaluate at the hard tissue level the effect of C. albicans on the cariogenic potential of S. mutans biofilms focusing on the mineral profile of induced carious lesions. This study also aimed to evaluate the effect of C. albicans on the acidogenic potential of S. mutans biofilms. METHODOLOGY Dual-species (CA+SM) and single-species biofilms (CA or SM) were grown on the surface of enamel slabs in the presence of glucose/sucrose supplemented culture medium for 24, 48 and 72 hours. Demineralization was evaluated through percentage of surface microhardness change (%SMC) and transversal microradiography analysis (ILM and LD) and pH of the spent medium was recorded daily. Data were analyzed by two-way ANOVA followed by Bonferroni correction. RESULTS%SMC was statistically different among the biofilms at each time point being the highest for SM biofilms and the lowest for CA biofilms which also differed from CA+SM biofilms [SM (24 h: 47.0±7.3; 48 h: 66.3±8.3; 72 h: 75.4±3.9); CA (24 h: 7.3±3.3; 48 h: 7.1±6.4; 72 h: 6.6±3.6); CA+SM (24 h: 35.9±7.39.1; 48 h: 47.2±9.5; 72 h: 47.6±9.5)]. pH of spent medium was statistically lower for SM biofilms compared to the other biofilms at each time point and remained constant over time while pH values increased from 24 to 72 h for both CA and CA+SM biofilms [SM (24 h: 4.4±0.1; 48 h: 4.4±0.1; 72 h: 4.5±0.1); CA (24 h: 6.9±0.3; 48 h: 7.2±0.2; 72 h: 7.5±0.2); CA+MS (24 h: 4.7±0.2; 48 h: 5.1±0.1; 72 h: 6.1±0.6)]. IML and LD for SM biofilms increased over time while no difference was observed from 24 to 72 h for the other biofilms. CONCLUSIONS The present data suggest that C. albicans has low enamel demineralization potential and the presence of C. albicans can reduce both the cariogenic and acidogenic potentials of S. mutans biofilms.