Stress salinity in plants: New strategies to cope with in the foreseeable scenario.

The excess of salts in soils causes stress in most plants, except for some halophytes that can tolerate higher levels of salinity. The excess of Na+ generates an ionic imbalance, reducing the K+ content and altering cellular metabolism, thus impacting in plant growth and development. Additionally, salinity in soil induces water stress due to osmotic effects and increments the production of reactive oxygen species (ROS) that affect the cellular structure, damaging membranes and proteins, and altering the electrochemical potential of H+, which directly affects nutrient absorption by membrane transporters. However, plants possess mechanisms to overcome the toxicity of the sodium ions, such as internalization into the vacuole or exclusion from the cell, synthesis of enzymes or protective compounds against ROS, and the synthesis of metabolites that help to regulate the osmotic potential of plants. Physiologic and molecular mechanisms of salinity tolerance in plants will be addressed in this review. Furthermore, a revision of strategies taken by researchers to confer salt stress tolerance on agriculturally important species are discussed. These strategies include conventional breeding and genetic engineering as transgenesis and genome editing by CRISPR/Cas9.

KS-WNK1 is required for the renal response to extreme changes in potassium intake.

Kidney-specific with-no-lysine kinase 1 (KS-WNK1) is an isoform of WNK1 kinase that is predominantly found in the distal convoluted tubule of the kidney. The precise physiological function of KS-WNK1 remains unclear. Some studies have suggested that it could play a role in regulating potassium renal excretion by modulating the activity of the Na+-Cl- cotransporter (NCC). However, changes in the potassium diet from normal to high failed to reveal a role for KS-WNK1, but under a normal-potassium diet, the expression of KS-WNK1 is negligible. It is only detectable when mice are exposed to a low-potassium diet. In this study, we investigated the role of KS-WNK1 in regulating potassium excretion under extreme changes in potassium intake. After following a zero-potassium diet (0KD) for 10 days, KS-WNK1-/- mice had lower plasma levels of K+ and Cl- while exhibiting higher urinary excretion of Na+, Cl-, and K+ compared with KS-WNK1+/+ mice. After 10 days of 0KD or normal-potassium diet (NKD), all mice were challenged with a high-potassium diet (HKD). Plasma K+ levels markedly increased after the HKD challenge only in mice previously fed with 0KD, regardless of genotype. KSWNK1+/+ mice adapt better to HKD challenge than KS-WNK1-/- mice after a potassium-retaining state. The difference in the phosphorylated NCC-to-NCC ratio between KS-WNK1+/+ and KS-WNK1-/- mice after 0KD and HKD indicates a role for KS-WNK1 in both NCC phosphorylation and dephosphorylation. These observations show that KS-WNK1 helps the distal convoluted tubule to respond to extreme changes in potassium intake, such as those occurring in wildlife.NEW & NOTEWORTHY The findings of this study demonstrate that kidney-specific with-no-lysine kinase 1 plays a role in regulating urinary electrolyte excretion during extreme changes in potassium intake, such as those occurring in wildlife. .

Response to carvacrol monoterpene in the emergence of Allium cepa L. seeds exposed to salt stress.

Abiotic stresses including sodium chloride (NaCl) are known to negatively affect plant physiology and seed germination by inducing a delay in establishing seedling emergence. The monoterpene carvacrol is the major component of several aromatic plants and seems to interfere with germination and seedling growth. In this study, we investigated whether treatment with carvacrol attenuates the effects of NaCl on the germination and development of Allium cepa, where biochemical parameters were also analyzed. The results showed that the Emergency Speed Index (ESI) was near to 2.0 in the control group. The groups NaCl, carvacrol alone, and in co-treatment with NaCl exhibited an ESI below 0.8, being significantly smaller when compared to the control. NaCl + carvacrol significantly inhibited seed emergence in relation to the NaCl group. Only the content of malondialdehyde was significantly altered by NaCl.

Salt tolerance of endophytic root bacteria and their effects on seed germination and viability on tomato plants.

Salinity is one of the most brutal environmental factors limiting the productivity of agricultural lands worldwide. It is considered that the salinity may be one of the important reasons for the low yield in Igdir of the tomato plants, which is medium resistant (3-5 dS.m-1) among vegetables. Eco-friendly techniques such as endophytic root bacteria treatments (ERB) are needed to restore saline soils to agriculture and also to increase the yield of tomatoes. Endophytic bacteria colonizing the inside of plants increase plant growth by various mechanisms and also mitigate the adverse effects of biotic and abiotic stresses on plants. In this study, endophytic bacteria were isolated from the roots of tomato plants exposed to salt stress. Then, these isolates' tolerance levels to different NaCl (0, 0.1, 0.2, 0.4, 0.8 M) concentrations and their potential to promote plant growth (PGP) traits were determined. It was recorded that 14.8% of the isolates whose salt tolerance was tested were highly tolerant to NaCl and 18.5% were highly susceptible. The tested ERB isolates exhibited typical PGP characteristics such as siderophore production (4-30 mm diameter), phosphate solubilizing activity (6-16 mm diameter), and IAA production activity (24.9-171.6 µg/ml). Moreover, it was determined that the nitrogen fixation potential is high 55.7% of the isolates tested, and 11.1% low. In addition, the effects of ERB treatments on germination and vigor index in two tomato cultivars under standard and saline conditions in the lab were evaluated. Some ERB isolates in tomato plants under standard and saline conditions increased seed viability, hypocotyl length, root length, and seedling fresh weight, and also accelerated germination.

Complete genome sequence of Exiguobacterium profundum TSS-3 isolated from an extremely saline-alkaline spring located in Ixtapa, Chiapas-México.

We report the complete genome sequence of Exiguobacterium profundum TSS-3, a strain isolated from the sediment of an extremely saline-alkaline spring located in Ixtapa, Chiapas-México (16° 47´ LN and 92° 54´ LO). Its genome is composed of a 2.8-Mb chromosome and a small 4.6-Kb plasmid.

Mass transfer modeling during wet salting of caiman meat (Caiman crocodilus yacare) at different brine temperatures.

Caiman meat is considered exotic and its consumption has significantly increased due to its nutritional quality. This study aimed to evaluate the kinetics of water content (WC) and salt content (SC) at different temperatures (1, 5, 10 and 15 °C) and to evaluate the use of mathematical models to predict the mass transfer kinetics until equilibrium conditions during the wet salting of caiman tail fillets. Moisture and chloride analyses were performed throughout the wet salting process. Four models (Peleg; Weibull; Zugarramurdi and Lupín; Diffusion) were tested to predict WC and SC kinetics in caiman tail fillets subjected to wet salting. The increase in the temperature resulted in a reduction (P < 0.05) in WC and an increase (P < 0.05) in SC. Nonlinear effects on WC and SC kinetics were observed between the different temperatures evaluated. Furthermore, the effective diffusion coefficients (Dw and Ds) increased (P < 0.05) with increasing temperature. Peleg, Weibull, Zugarramurdi and Lupín, and the Diffusion model satisfactorily represented WC and SC rates throughout the process. The kinetic behavior of the parameters of the models corroborated the effects of temperature on those parameters. Peleg was the best model for predicting WC and SC kinetics, and Zugarramurdi and Lupín was the best for predicting the equilibrium conditions of the process (WC∞ SC∞), all parameters which can be used to describe the mass transfer kinetics during wet salting of caiman tail fillets.

Control of sodium and potassium homeostasis by renal distal convoluted tubules

Distal convoluted tubules (DCT), which contain the Na-Cl cotransporter (NCC) inhibited by thiazide diuretics, undergo complex modulation to preserve Na+ and K+ homeostasis. The lysine kinases 1 and 4 (WNK1 and WNK4), identified as hyperactive in the hereditary disease pseudohypoaldosteronism type 2, are responsible for activation of NCC and consequent hypokalemia and hypertension. WNK4, highly expressed in DCT, activates the SPAK/OSR1 kinases, which phosphorylate NCC and other regulatory proteins and transporters in the distal nephron. WNK4 works as a chloride sensor through a Cl- binding site, which acts as an on/off switch at this kinase in response to changes of basolateral membrane electrical potential, the driving force of cellular Cl- efflux. High intracellular Cl- in hyperkalemia decreases NCC phosphorylation and low intracellular Cl- in hypokalemia increases NCC phosphorylation and activity, which makes plasma K+ concentration a central modulator of NCC and of K+ secretion. The WNK4 phosphorylation by cSrc or SGK1, activated by angiotensin II or aldosterone, respectively, is another relevant mechanism of NCC, ENaC, and ROMK modulation in states such as volume reduction, hyperkalemia, and hypokalemia. Loss of NCC function induces upregulation of electroneutral NaCl reabsorption by type B intercalated cells through the combined activity of pendrin and NDCBE, as demonstrated in double knockout mice (KO) animal models, Ncc/pendrin or Ncc/NDCBE. The analysis of ks-Nedd-4-2 KO animal models introduced the modulation of NEDD4-2 by intracellular Mg2+ activity as an important regulator of NCC, explaining the thiazide-induced persistent hypokalemia.

Germination of Dypsis decaryi seeds under salt stress / Germinação de sementes de Dypsis decaryi submetidas ao estresse salino

The triangle palm (Dypsis decaryi), a species native to Madagascar, possesses various ornamental characteristics that make it highly valued in the international market. Seed propagation is the primary method for its cultivation, and this process is influenced by factors such as sowing time and salinity. In this study, we aimed to investigate the germination behavior of D. decaryi seeds under different saline concentrations of sodium chloride (NaCl) and potassium chloride (KCl), in two distinct periods. The experiment followed a completely randomized design, employing a 2 × 2 × 5 factorial arrangement corresponding to two seasons of experimentation (summer and winter), two salt types (NaCl and KCl), and four salt concentrations (25, 50, 75, and 100 mM), in addition to a control group without salt. Each treatment consisted of four replications, with 25 seeds per replication. The evaluated parameters were germination percentage, germination speed index, and mean germination time. No significant effects were observed when analyzing the salt types individually, the interaction between seasons and salts, or the interaction between all three factors. However, during the summer season, the seeds exhibited higher mean germination percentages and germination speed indices and shorter mean germination times, regardless of the salt used. A high germination percentage (73.79%) was observed at the highest salt concentration tested for both NaCl and KCl. Consequently, we conclude that D. decaryi is tolerant to salinity, as simulated by KCl and NaCl, during the seed germination process. Sowing time, salt concentrations, and the interaction between these variables influenced germination.(AU)

A palmeira triângulo (Dypsis decaryi), nativa de Madagascar, apresenta diversas características de interesse ornamental, tornando-a uma espécie importante para o mercado internacional. Seu principal método de propagação é por semente, que é influenciado por vários fatores como época de semeadura e salinidade. Propôs-se avaliar o comportamento germinativo de sementes de D. decaryi em diferentes concentrações salinas de cloreto de sódio (NaCl) e cloreto de potássio (KCl) em duas épocas. O delineamento experimental foi o inteiramente casualizado; o experimento foi realizado em esquema fatorial 2 x 2 x 5, sendo duas épocas de condução do experimento (verão e inverno), dois tipos de sais (NaCl e KCl) e quatro concentrações salinas (25, 50, 75 e 100 mM) e ausência de sais - controle; foram quatro repetições e 25 sementes por parcela. Avaliou-se porcentagem de germinação, índice de velocidade de germinação e tempo médio de germinação. Não houve efeito significativo de forma isolada entre os tipos de sais, para interação de épocas e sais e, entre os três fatores avaliados. Observou-se que no verão as sementes apresentaram maiores médias de porcentagem de germinação, maior índice de velocidade de germinação, e menor tempo médio de germinação para ambos os sais. Foi possível observar alta porcentagem de germinação (73,79%) na maior concentração salina avaliada para ambos os sais. Concluiu-se que a espécie se mostrou tolerante à salinidade simulada por KCl e NaCl, durante o processo de germinação de sementes, o qual foi influenciado pela época de semeadura, concentrações salinas e interação entre épocas e concentrações.(AU)

Hypertonic Solution in Severe COVID-19 Patient: A Potential Adjuvant Therapy.

Coronavirus disease 2019 (COVID-19) features hyper-inflammation, cytokine storm, neutrophil function changes, and sodium chloride (NaCl) homeostasis disruption, while the treatment with NaCl hypertonic solutions (HS) controls electrolytic body homeostasis and cell functions. HS treatment is a simple, popular, economic, and feasible therapy to regulate leukocyte function with a robust anti-inflammatory effect in many inflammatory diseases. The purpose of this narrative review is to highlight the knowledge on the use of HS approaches against viral infection over the past years and to describe the mechanisms involved in the release of neutrophil extracellular traps (NETs) and production of cytokine in severe lung diseases, such as COVID-19. We reported the consequences of hyponatremia in COVID-19 patients, and the immunomodulatory effects of HS, either in vitro or in vivo. We also described the relationship between electrolyte disturbances and COVID-19 infection. Although there is still a lack of clinical trials, hypertonic NaCl solutions have marked effects on neutrophil function and NETs formation, emerging as a promising adjuvant therapy in COVID-19.

Histological Identification and Quantification of Eosinophils and Ascites in Leghorn Chickens Treated with High Oral Concentrations of NaCl-Pilot Study.

The purpose of this pilot study was to determine the role played by eosinophils in NaCl poisoning and right cardiac hypertrophy (ascitic syndrome) in Leghorn chickens, as well as the histological findings in the central nervous system (CNS), liver, and kidney. Moreover, the hypertrophy of the right ventricle index (HRVI) as an indicator of ascites was evaluated. Male SPF Leghorn birds at 28 days of age were submitted to two experiments. Food and water (FW) experiment: birds were treated with food plus 3.3% NaCl for the next 27 days and 1% NaCl in their drinking water from days 22 to 27. Water experiment (W): birds were treated with 1% NaCl in their drinking water for 5 days. In both experiments, the chickens exhibited loss of appetite, diuresis, and watery, green diarrhea during treatment days; at 24−27 td-FW and experiment W, the birds showed nervous signology (prostration, running movements, tremors, and comatose state). In the leukogram at 28 td-FW, an increase (p < 0.05) in heterophiles and basophils was observed. CNS eosinophilia was not observed in birds intoxicated with NaCl, though they did present demyelination in the brain and spinal cord, hepatic degeneration, mesangial proliferative glomerulopathy, and acute proximal renotubular necrosis.

Species Surface Distribution and Surface Tension of Aqueous Solutions of MIBC and NaCl Using Molecular Dynamics Simulations.

Methyl isobutyl carbinol (MIBC) is a high-performance surfactant with unusual interfacial properties much appreciated in industrial applications, particularly in mineral flotation. In this study, the structure of air-liquid interfaces of aqueous solutions of MIBC-NaCl is determined by using molecular dynamics simulations employing polarizable and nonpolarizable force fields. Density profiles at the interfaces and surface tension for a wide range of MIBC concentrations reveal the key role of polarizability in determining the surface solvation of Cl- ions and the expulsion of non-polarizable Na+ ions from the interface to the liquid bulk, in agreement with spectroscopic experiments. The orientation of MIBC molecules at the water liquid-vapor interface changes as the concentration of MIBC increases, from parallel to the interface to perpendicular, leading to a well-packed monolayer. Surface tension curves of fresh water and aqueous NaCl solutions in the presence of MIBC intersect at a reproducible surfactant concentration for a wide range of salt concentrations. The simulation results for a 1 M NaCl aqueous solution with polarizable water and ions closely capture the MIBC concentration at the intercept. The increase in surface tension of the aqueous MIBC/NaCl mixture below the concentration of MIBC at the intersection seems to originate in a disturbance of the interfacial hydrogen bonding structure of the surface liquid water caused by Na+ ions acting at a distance and not by its presence on the interface.

Surviving in the Brine: A Multi-Omics Approach for Understanding the Physiology of the Halophile Fungus Aspergillus sydowii at Saturated NaCl Concentration.

Although various studies have investigated osmoadaptations of halophilic fungi to saline conditions, only few analyzed the fungal mechanisms occurring at saturated NaCl concentrations. Halophilic Aspergillus sydowii is a model organism for the study of molecular adaptations of filamentous fungi to hyperosmolarity. For the first time a multi-omics approach (i.e., transcriptomics and metabolomics) was used to compare A. sydowii at saturated concentration (5.13 M NaCl) to optimal salinity (1 M NaCl). Analysis revealed 1,842 genes differentially expressed of which 704 were overexpressed. Most differentially expressed genes were involved in metabolism and signal transduction. A gene ontology multi-scale network showed that ATP binding constituted the main network node with direct interactions to phosphorelay signal transduction, polysaccharide metabolism, and transferase activity. Free amino acids significantly decreased and amino acid metabolism was reprogrammed at 5.13 M NaCl. mRNA transcriptional analysis revealed upregulation of genes involved in methionine and cysteine biosynthesis at extreme water deprivation by NaCl. No modifications of membrane fatty acid composition occurred. Upregulated genes were involved in high-osmolarity glycerol signal transduction pathways, biosynthesis of ß-1,3-glucans, and cross-membrane ion transporters. Downregulated genes were related to the synthesis of chitin, mannose, cell wall proteins, starvation, pheromone synthesis, and cell cycle. Non-coding RNAs represented the 20% of the total transcripts with 7% classified as long non-coding RNAs (lncRNAs). The 42% and 69% of the total lncRNAs and RNAs encoding transcription factors, respectively, were differentially expressed. A network analysis showed that differentially expressed lncRNAs and RNAs coding transcriptional factors were mainly related to the regulation of metabolic processes, protein phosphorylation, protein kinase activity, and plasma membrane composition. Metabolomic analyses revealed more complex and unknown metabolites at saturated NaCl concentration than at optimal salinity. This study is the first attempt to unravel the molecular ecology of an ascomycetous fungus at extreme water deprivation by NaCl (5.13 M). This work also represents a pioneer study to investigate the importance of lncRNAs and transcriptional factors in the transcriptomic response to high NaCl stress in halophilic fungi.

Identification of ESR centers and their role in the TL of natural salt from Lluta, Peru.

In this study, the thermoluminescence (TL) properties of natural NaCl from Lluta, Arequipa-Peru was investigated. The number of peaks and the kinetic parameters associated with the TL glow peaks of NaCl sample after gamma-irradiation were analyzed by initial rise and deconvolution method. Defect centers induced in pure salt by gamma irradiation have been studied by electron spin resonance (ESR) with a view to identify the centers associated with the TL process in the salt. Thermal annealing experiments indicate the presence of three defect centers. Center I characterized by the g-value 2.011 is identified as an O- ion and relates with the dominant TL peak at 220 °C. Center II with a g-value of 2.0058 is attributed to a F center and is found to correlate with the 128 °C TL peak. Center III has of g-value 2.014 and is also assigned to an O- ion.

Effect of the Integrated Addition of a Red Tara Pods (Caesalpinia spinosa) Extract and NaCl over the Neo-Formed Contaminants Content and Sensory Properties of Crackers.

A 2k factorial design with three centrals points was considered to evaluate the effect of adding red Tara pods extract (Caesalpinia spinosa) (440-2560 µg/mL of dough water) and NaCl (0.3-1.7 g/100 g of flour) on the acrylamide (AA) and hydroxymethylfurfural (HMF) content and sensory attributes of crackers. Additionally, the best formulation, defined as that with the lowest AA and HMF content, was compared with a commercial formulation cracker. Red Tara pods extracts were obtained through conventional extraction using pure water (60 °C, 35 min). AA and HMF content were quantified by GC-MS and HPLC-DAD, respectively. The sensory evaluation was carried out using a descriptive analysis on a 10 cm non-structured linear scale. Red Tara pods extract significantly reduced (p < 0.05) the AA and HMF content, while NaCl only influenced the HMF formation. However, the sensory attributes did not significantly change (p > 0.05), excepting the violet-gray color and salty flavor, but at acceptable levels compared with the control sample. The higher the red Tara pods extract concentration (2560 µg/mL of dough water), the lower the neo-formed contaminants (NFCs) content of crackers (AA: 53 µg/kg and HMF: 1236 µg/kg) when salt level was below 3 g/100 g of flour. The action of the proanthocyanidins present in the extracts which trapped the carbonyl groups of sugars probably avoided the formation of both NFCs. Contrarily, NaCl addition (from 0.3 to 1.7 g/100 g of flour) significantly increased (p < 0.05) the HMF formation (from 1236 µg/kg to 4239 µg/kg, respectively), probably through the dehydration of carbohydrates during the Maillard reaction. When explored treatments were compared with a commercial formulated cracker, the highest mitigation effect (reductions of 40% and 32% AA and HMF, respectively) was reached with the addition of 2560 µg/mL of dough water of red Tara pods extract and 0.3 g/100 g of flour of NaCl. The addition of red Tara pods extracts integrated with the control of NaCl levels mitigated the NFCs in crackers, preserving their sensory properties. Future research should be focused on scaling this mitigation technology, considering a better chemical characterization of red Tara pods extracts as well as the validation of its use as functional food ingredient.

Vermicompost humates as a salinity mitigator in the germination of basil / Vermicomposto humato como mitigador de salinidade na germinação de basil

This study determined the effect of vermicompost humates as salinity mitigator in germination and morphometric characteristics of basil varieties seedlings, tolerant and sensitive to salinity, subjected to vermicompost humates diluted 1/60 (v/v) and 0, 50 and 100 mM NaCl in a completely randomized design with four replications. The rate and percentage of germination, root length, shoot height, root and shoot fresh and dry-weight were measured. The varieties showed differential response, highlighting Napoletano as the most tolerant. Vermicompost humates showed biostimulant effects on variables evaluated, allowing that tolerant variety to improve germination and growth, and increasing the salinity tolerance of the sensitive variety.

O objetivo foi determinar o efeito de humatas de vermicomposto como mitigador de salinidade na germinação e morfometria de mudas de variedades de manjericão, tolerantes e sensíveis à salinidade, submetidas a 0, 50 e 100 mM de NaCl e humatas de vermicomposto diluído 1/60 (v / v) em delineamento inteiramente casualizado com quatro repetições. Foram medidos a taxa e porcentagem de germinação, comprimento da radícula, altura da muda, comprimento da raiz, altura da parte aérea, raiz e biomassa fresca e seca da parte aérea. As variedades apresentaram resposta diferenciada, destacando-se o Napoletano como a mais tolerante. Humatos de vermicomposto mostraram efeitos bioestimulantes nas variáveis avaliadas, permitindo que a variedade tolerante melhorasse a germinação e o crescimento aumentando a tolerância à salinidade da variedade sensível.

Hypertonic solution in severe COVID-19 patient: a potential adjuvant therapy

Coronavirus disease 2019 (COVID-19) features hyper-inflammation, cytokine storm, neutrophil function changes, and sodium chloride (NaCl) homeostasis disruption, while the treatment with NaCl hypertonic solutions (HS) controls electrolytic body homeostasis and cell functions. HS treatment is a simple, popular, economic, and feasible therapy to regulate leukocyte function with a robust anti-inflammatory effect in many inflammatory diseases. The purpose of this narrative review is to highlight the knowledge on the use of HS approaches against viral infection over the past years and to describe the mechanisms involved in the release of neutrophil extracellular traps (NETs) and production of cytokine in severe lung diseases, such as COVID-19. We reported the consequences of hyponatremia in COVID-19 patients, and the immunomodulatory effects of HS, either in vitro or in vivo. We also described the relationship between electrolyte disturbances and COVID-19 infection. Although there is still a lack of clinical trials, hypertonic NaCl solutions have marked effects on neutrophil function and NETs formation, emerging as a promising adjuvant therapy in COVID-19.

The Enhancement of Enargite Dissolution by Sodium Hypochlorite in Ammoniacal Solutions.

The dissolution of both copper and arsenic from a copper concentrate was investigated in oxidative ammonia/ammonium solutions at moderate temperatures and atmospheric pressure. The main parameters studied were temperature, pH, concentrations of different ammonia salts, the presence of sodium hypochlorite, pretreatment with sodium chloride, and curing period. In all ammoniacal solutions studied, increasing the temperature enhanced the dissolution of copper, but the dissolution of arsenic remained marginal. Mixing the copper concentrate with sodium chloride and leaving it to rest for 72 h before leaching in ammoniacal solutions significantly increased the dissolution of copper and slightly increased the dissolution of arsenic from the concentrate. A maximum of 35% of Cu and 3.3% of As were extracted when ammonium carbonate was used as the lixiviant. The results show relatively rapid dissolution of the concentrate with the addition of sodium hypochlorite in ammonium carbonate solution, achieving a dissolution of up to 50% and 25% of copper and arsenic, respectively. A copper dissolution with a non-linear regression model was proposed, considering the effect of NaClO and NH4Cl at 25 °C. These findings highlight the importance of using the correct anionic ligands for the ammonium ions and temperature to obtain a high dissolution of copper or arsenic. The results also showed that the curing time of the packed bed before the commencement of leaching appeared to be an important parameter to enhance the dissolution of copper and leave the arsenic in the residues.

The effect of sodium chloride and temperature on the levels of transcriptional expression of staphylococcal enterotoxin genes in Staphylococcus aureus isolates from broiler carcasses.

Staphylococcus aureus is one of the most common pathogens associated with food poisoning, which is caused by the ingestion of food contaminated with staphylococcal enterotoxins (SE). Our study aims at evaluating the occurrence and expression of five SE genes (sea, seb, sec, sed, and see) in S. aureus previously isolated from broiler carcasses. Besides that, it also presents an in vitro analysis of the effects of sodium chloride and temperature on the levels of transcriptional expression. A total of 30 S. aureus isolates were investigated for the presence of SEs by PCR assay. The expression level and the effects of sodium chloride (2.5% NaCl), as well as temperature (8 ºC and 12 ºC), on the transcriptional expression, were evaluated by a quantitative reverse transcription PCR (RT-qPCR). Twelve isolates carried at least one of the SE genes. Among them, five representative isolates presented transcriptional expression for at least one gene. Both sodium chloride and low temperatures interfered with the expression of the SE genes, decreasing their values. However, one isolate displayed relative expression 2.25 times higher for sed gene than S. aureus FRI 361 in optimal conditions (p < 0.05), demonstrating their toxigenic potential even under salt stress. There was no evidence of enterotoxin gene expression at 8 ºC.

Mass transfer in beef: effect of crossbreeding and ultrasound application

Cuts of muscle (biceps femoris) from three crossbreeds between the Nelore, Angus and Wagyu breeds of cattle (Crossbreed 1 (C1): ½ Angus and ½ Nelore; Crossbreed 2 (C2): ¾ Angus and » Nelore; Crossbreed 3 (C3): ½ Wagyu, » Nelore and » Angus) were characterized by their chemical composition, pH, water activity and lipid oxidation. The cuts were submitted to wet brining in a 5 % NaCl concentration at 5 °C with either static brine (SB) or brine assisted with ultrasound (US). Samples of the treatments were taken after 30, 60, and 120 min of wet brining for later analysis. The experimental data were adjusted using the Peleg and Page models, and the Page template best described the experimental data. The crossbreeding did not affect the water and ash content; however, it significantly affected the levels of lipids and proteins. C3 presented higher fat content than C2, which, in turn, was higher than C1. C1 had higher protein content than C2, which had more protein than C3. When ultrasound was applied, crossbreeding influenced the water content and the water absorption rate during brining, which had the highest values for the highest protein content. The crossbreeding and ultrasound application also affected the NaCl content of the cuts. However, only ultrasound application increased the rate of NaCl absorption during wet brining. The results demonstrate that ultrasound accelerates the mass transfer in wet brining of the cuts of beef, regardless of the crossbreeds studied.

Reduction of sodium content in pork coppa: physicochemical, microbiological and sensory evaluation

Sodium reduction and the substitution of sodium chloride by other salts have been extensively studied in order to produce healthier foods. Coppa is a pork cured product that receives high levels of sodium through the salting process. The objective of this work was to evaluate the impact of reductions in Sodium Chloride (NaCl), substitution by Potassium Chloride (KCl) and reductions in the re-salting time on the physicochemical, microbiological and sensorial characteristics in pork coppa. Four treatments were applied: T1 with 2 days of salting, 2 days of re-salting and 35 % reduction of NaCl; T2 with 2 days of salting and 3 days of re-salting and 35 % reduction of NaCl; T3 with 2 days of salting and 2 days of re-salting and replacing 35 % of NaCl by KCl; T4 with 2 days of salting and 3 days of re-salting and 35 % replacing NaCl by KCl. Control: standard treatment was applied with 100 % of NaCL and salting time was 2 days and then 5 days to re-salting. The reduction in sodium content in processed pork Coppa produced no microbiological nor physicochemical changes. The reduction in salting together with salting and re-salting time and the partial replacement of NaCl by KCl resulted in reductions from 2,000 mg to 1,600 mg of sodium. Sensory evaluation demonstrated that the reduction in re-salting time was efficient using the ideal profile method which showed that treatments T1 and T2 were efficient in creating a product that meets consumer expectations.