Activity of (-)-Camphene Derivatives Against Mycobacterium tuberculosis in Acidic pH.

BACKGROUND: For more than 60 years, the lack of new anti-tuberculosis drugs and the increase of resistant Mycobacterium tuberculosis lineages exhibit a therapeutic challenge, demanding new options for the treatment of resistant tuberculosis. OBJECTIVE: Herein, we determined the (i) activities of (-)-camphene and its derivatives and (ii) combinatory effect with pyrazinamide (PZA) against Mycobacterium tuberculosis in acidic pH and (iii) cytotoxicity on VERO cells. METHODS: The activity of (-)-camphene and its 15 derivatives was determined in M. tuberculosis H37Rv in culture medium at pH 6.0 by Resazurin Microtiter Assay Plate (REMA). The activity and combinatory study of three (-)-camphene derivatives with PZA was carried out on seven multidrugresistant (MDR) clinical isolates by REMA and Checkerboard, respectively. The assay of 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) bromide in VERO cells was used to determine the derivatives' cytotoxicity. RESULTS: Four (-)-camphene derivatives, (4), (5a) (5d) and (5h), showed a reduction in the MIC value at pH 6.0 compared to the MIC detected at pH 6.8 in M. tuberculosis H37Rv and multidrug resistant clinical isolates. Three (-)-camphene derivatives, (4), (5d) and (5h), showed synergistic effect (FICI ≤ 0.5) combined with PZA and were more selective for M. tuberculosis than VERO cell (selective index from 7.7 to 84.2). CONCLUSION: Three (-)-camphene derivatives have shown to be promising anti-TB molecule scaffolds due to their low MIC values in acidic pH against MDR M. tuberculosis clinical isolates, synergism with PZA and low cytotoxicity.

Water pH and hardness alter ATPases and oxidative stress in the gills and kidney of pacu ( Piaractus mesopotamicus )

This study aimed to assess the effects of low and high water hardness in interaction with different water pH in pacu (Piaractus mesopotamicus). Pacu juveniles were subjected to low (50 mg CaCO3 L-1 - LWH) or high water hardness (120 mg CaCO3 L-1 - HWH) at water pH of 5.5 (acidic), 7.5 (circumneutral) or 9.0 (alkaline) for 15 days. Gills and kidneys were collected (days 1, 5 and 15). Gill Na+/K+-ATPase (NKA) and vacuolar-type H+-ATPase (V-ATPase) activities were higher in alkaline pH with HWH on day 1. Gill and kidney NKA and V-ATPase activities were higher in acidic pH with LWH on day 15. Gill NKA activity of pacus under alkaline pH with LWH was higher than those exposed to HWH. Reduced antioxidant capacity in the gills and kidney and enhanced thiobarbituric acid reactive substances (TBARS) levels were demonstrated in fish exposed to acidic or alkaline pH, mainly with LWH. HWH increased glutathione-S-transferase (GST) activity and reduced TBARS levels in the gills and kidney. On day 15, GST activity was increased at acidic pH with LWH. In conclusion, circumneutral pH presents less oxidative stress and fewer variations in ATPases and HWH reduced deleterious effects in fish exposed to acidic or alkaline pH.(AU)

Este estudo objetivou analisar o efeito de baixa e alta dureza da água em interação com diferentes pH da água em pacu (Piaractus mesopotamicus). Juvenis de pacu foram submetidos a baixa (50 mg CaCO3 L-1 - BDA) ou alta dureza da água (120 mg CaCO3 L-1 - ADA) em pH da água de 5.5 ácido), 7.5 (circum-neutro) ou 9.0 (alcalino) por 15 dias. Foram coletados brânquias e rim (dias 1, 5 e 15). Atividade de Na+/K+-ATPase (NKA) e H+-ATPase do tipo vacuolar (V-ATPase) branquial foram maiores em pH alcalino com ADA no dia 1. Atividade de NKA e V-ATPase branquial e renal foram maiores em pH ácido com BDA no dia 15. Atividade de NKA branquial de pacus submetidos a pH alcalino com BDA foi maior que aqueles expostos para ADA. Em peixes expostos a pH ácido ou alcalino com BDA houve redução da capacidade antioxidante nas brânquias e rim e aumento dos níveis de "substâncias reativas ao ácido tiobarbitúrico" (TBARS). Em ADA aumentou a atividade da "glutationa-S-transferase" (GST) e reduziu níveis de TBARS nas brânquias e rim. No dia 15, a atividade da GST foi maior em pH ácido com BDA. Em conclusão, pH circum-neutro apresentou menor estresse oxidativo e poucas variações na atividade de ATPases e ADA reduziu efeitos deletérios em peixes expostos a pH ácido ou alcalino.(AU)

Water pH and hardness alter ATPases and oxidative stress in the gills and kidney of pacu ( Piaractus mesopotamicus )

This study aimed to assess the effects of low and high water hardness in interaction with different water pH in pacu (Piaractus mesopotamicus). Pacu juveniles were subjected to low (50 mg CaCO3 L-1 - LWH) or high water hardness (120 mg CaCO3 L-1 - HWH) at water pH of 5.5 (acidic), 7.5 (circumneutral) or 9.0 (alkaline) for 15 days. Gills and kidneys were collected (days 1, 5 and 15). Gill Na+/K+-ATPase (NKA) and vacuolar-type H+-ATPase (V-ATPase) activities were higher in alkaline pH with HWH on day 1. Gill and kidney NKA and V-ATPase activities were higher in acidic pH with LWH on day 15. Gill NKA activity of pacus under alkaline pH with LWH was higher than those exposed to HWH. Reduced antioxidant capacity in the gills and kidney and enhanced thiobarbituric acid reactive substances (TBARS) levels were demonstrated in fish exposed to acidic or alkaline pH, mainly with LWH. HWH increased glutathione-S-transferase (GST) activity and reduced TBARS levels in the gills and kidney. On day 15, GST activity was increased at acidic pH with LWH. In conclusion, circumneutral pH presents less oxidative stress and fewer variations in ATPases and HWH reduced deleterious effects in fish exposed to acidic or alkaline pH.(AU)

Este estudo objetivou analisar o efeito de baixa e alta dureza da água em interação com diferentes pH da água em pacu (Piaractus mesopotamicus). Juvenis de pacu foram submetidos a baixa (50 mg CaCO3 L-1 - BDA) ou alta dureza da água (120 mg CaCO3 L-1 - ADA) em pH da água de 5.5 ácido), 7.5 (circum-neutro) ou 9.0 (alcalino) por 15 dias. Foram coletados brânquias e rim (dias 1, 5 e 15). Atividade de Na+/K+-ATPase (NKA) e H+-ATPase do tipo vacuolar (V-ATPase) branquial foram maiores em pH alcalino com ADA no dia 1. Atividade de NKA e V-ATPase branquial e renal foram maiores em pH ácido com BDA no dia 15. Atividade de NKA branquial de pacus submetidos a pH alcalino com BDA foi maior que aqueles expostos para ADA. Em peixes expostos a pH ácido ou alcalino com BDA houve redução da capacidade antioxidante nas brânquias e rim e aumento dos níveis de "substâncias reativas ao ácido tiobarbitúrico" (TBARS). Em ADA aumentou a atividade da "glutationa-S-transferase" (GST) e reduziu níveis de TBARS nas brânquias e rim. No dia 15, a atividade da GST foi maior em pH ácido com BDA. Em conclusão, pH circum-neutro apresentou menor estresse oxidativo e poucas variações na atividade de ATPases e ADA reduziu efeitos deletérios em peixes expostos a pH ácido ou alcalino.(AU)

Acidic Dressing Based on Agarose/Cs2.5H0.5PW12O40 Nanocomposite for Infection Control in Wound Care.

Regulation of wound pH from alkaline to acidic is a simple and powerful approach to reduce wound microbial colonization and infection. Here, we present a nanocomposite material possessing intrinsic acidic surface pH as an innovative antimicrobial wound dressing. This material comprises an agarose matrix nanocomposite containing nanoparticles (NPs) of the cesium salt of phosphotungstic heteropolyacid (Cs2.5H0.5PW12O40). Self-supporting films were prepared by a casting method incorporating 5-20 wt % Cs2.5H0.5PW12O40 NPs into the matrix. Films are flexible with tensile strengths between 28.55 and 32.15 MPa and exhibit broad biocidal activity against neutralophilic pathogens, including Gram-positive bacteria, Gram-negative bacteria, yeast, and filamentous fungi. The nano-antimicrobial Cs2.5H0.5PW12O40 functions as an efficient and self-controlled proton delivery agent that lowers the surface pH of the nanocomposites to the range 7.0 > pH ≥ 3.0. Nanocomposite films containing 20 wt % Cs2.5H0.5PW12O40 NPs presented a surface pH of 3.0 and highest antimicrobial activity. Using quantitative reverse transcription polymerase chain reaction, we demonstrated that the antimicrobial mechanism of the nanocomposites is acid-induced because of the transcriptional induction of glutamate-dependent acid resistance genes in Escherichia coli. Additionally, nanocomposite films do not damage skin according to an in vivo rabbit skin model with no derived edema or erythema. The wound care safety of this material is due to low release of heavy metal heteropolyanions ([PW12O40]3-), no nanoparticle leaching, and proton controlled release resulting in nonirritating acid levels for human skin models.

Biofilm formation on different pH conditions by Streptococcus agalactiae isolated from bovine mastitic milk.

Streptococcus agalactiae is among the most relevant aetiologic agent of bovine clinical and subclinical mastitis, a major problem for the dairy industry. In Brazil, clonal diversity, capsular typing and multidrug resistance profiles of S. agalactiae related to human and bovine infections need further investigation. Presently, S. agalactiae isolates of bovine subclinical mastitis, from Brazilian Northeastern region, were submitted to capsular and pulsed-field gel electrophoresis (PFGE)-typing, antimicrobial susceptibility and assays of biofilm formation at different time incubation and pH levels. Sixteen bovine isolates were characterized by polymerase chain reaction assay as S. agalactiae capsular type II (CTII) and classified by PFGE in A1/A2 (n = 06), B1/B2 (n = 06), C (n = 03) and D (n = 01) patterns. Bovine S. agalactiae CTII strains were classified as 25% multidrug-resistant (MDR) with susceptibility to penicillin, linezolid and vancomycin. Biofilm formation on abiotic surface was strain- and time-dependent with significantly higher rates at pH 6·5. In conclusion, S. agalactiae capsular type II isolates recovered from bovine subclinical mastitis produced different pH-dependent biofilm levels. Our findings suggest that biofilm production is modulated by environmental factors and provides S. agalactiae advantageous in colonizing mammary gland during mastitis development, including MDR strains. SIGNIFICANCE AND IMPACT OF THE STUDY: Streptococcus agalactiae is among the most relevant aetiologic agent of bovine clinical and subclinical mastitis, a major problem for the dairy industry. The disease may cause significant economic loss due to decreased production and milk quality and increased use of medicaments. Presently, data demonstrated that biofilm formation favours the establishment of infectious process in health mammary tissue by S. agalactiae and emphasizes that an acidic pH promotes adhesion by biofilm-forming bacterial strains. S. agalactiae strains (25%) showed resistance to tetracycline, azithromycin, erythromycin and clindamycin, and consequently were classified as multidrug-resistant strains.

Triportheus albus Cope, 1872 in the Blackwater, Clearwater, and Whitewater of the Amazon: A Case of Phenotypic Plasticity?

The Amazon basin includes 1000s of bodies of water, that are sorted according to their color in three types: blackwater, clearwater, and whitewater, which significantly differ in terms of their physicochemical parameters. More than 3,000 species of fish live in the rivers of the Amazon, among them, the sardine, Triportheus albus, which is one of the few species that inhabit all three types of water. The purpose of our study was to analyze if the gene expression of T. albus is determined by the different types of water, that is, if the species presents phenotypic plasticity to live in blackwater, clearwater, and whitewater. Gills of T. albus were collected at well-characterized sites for each type of water. Nine cDNA libraries were constructed, three biological replicates of each condition and the RNA was sequenced (RNA-Seq) on the MiSeq® Platform (Illumina®). A total of 51.6 million of paired-end reads, and 285,456 transcripts were assembled. Considering the FDR ≤ 0.05 and fold change ≥ 2, 13,754 differentially expressed genes were detected in the three water types. Two mechanisms related to homeostasis were detected in T. albus that live in blackwater, when compared to the ones in clearwater and whitewater. The acidic blackwater is a challenging environment for many types of aquatic organisms. The first mechanism is related to the decrease in cellular permeability, highlighting the genes coding for claudin proteins, actn4, itgb3b, DSP, Gap junction protein, and Ca2+-ATPase. The second with ionic and acid-base regulation [rhcg1, slc9a6a (NHE), ATP6V0A2, Na+/K+-ATPase, slc26a4 (pedrin) and slc4a4b]. We suggest T. albus is a good species of fish for future studies involving the ionic and acid-base regulation of Amazonian species. We also concluded that, T. albus, shows well defined phenotypic plasticity for each water type in the Amazon basin.

Pharmacodynamic Evaluation of Fosfomycin against Escherichia coli and Klebsiella spp. from Urinary Tract Infections and the Influence of pH on Fosfomycin Activities.

Fosfomycin is widely used for the treatment of uncomplicated urinary tract infection (UTI), and it has recently been recommended that fosfomycin be used to treat infections caused by multidrug-resistant (MDR) Gram-negative bacilli. Whether urine acidification can improve bacterial susceptibility to fosfomycin oral dosing regimens has not been analyzed. The MIC of fosfomycin for 245 Gram-negative bacterial isolates, consisting of 158 Escherichia coli isolates and 87 Klebsiella isolates which were collected from patients with urinary tract infections, were determined at pH 6.0 and 7.0 using the agar dilution method. Monte Carlo simulation of the urinary fosfomycin area under the concentration-time curve (AUC) after a single oral dose of 3,000 mg fosfomycin and the MIC distribution were used to determine the probability of target attainment (PTA). Fosfomycin was effective against E. coli (MIC90 ≤ 16 µg/ml) but not against Klebsiella spp. (MIC90 > 512 µg/ml). Acidification of the environment increased the susceptibility of 71% of the bacterial isolates and resulted in a statistically significant decrease in bacterial survival. The use of a regimen consisting of a single oral dose of fosfomycin against an E. coli isolate with an MIC of ≤64 mg/liter was able to achieve a PTA of ≥90% for a target pharmacodynamic index (AUC/MIC) of 23 in urine; PTA was not achieved when the MIC was higher than 64 mg/liter. The cumulative fractions of the bacterial responses (CFR) were 99% and 55% against E. coli and Klebsiella spp., respectively, based on simulated drug exposure in urine with an acidic pH of 6.0. A decrease of the pH from 7.0 to 6.0 improved the PTA and CFR of the target pharmacodynamic index in both E. coli and Klebsiella isolates.

The effect of acidic pH and presence of metals as parameters in establishing a sulfidogenic process in anaerobic reactor.

The successful use of anaerobic reactors for bioremediation of acid mine drainage has been shown in systems with neutral pH. However, the choice of an efficient and suitable process for such wastewater must consider the capability of operating at acidic pH and in the presence of metals. This work studies the performance of an anaerobic batch reactor, under conditions of varying initial pH for its efficiencies in sulfate removal and metal precipitation from synthetic acid mine drainage. The chemical oxygen demand/sulfate (COD/SO4(2-)) ratio used was 1.00, with ethanol chosen as the only energy and carbon source. The initial pH of the synthetic drainage was progressively set from 7.0 to 4.0 to make it as close as possible to that of real acid mine drainage. Metals were also added starting with iron, zinc, and finally copper. The effectiveness of sulfate and COD removal from the synthetic acid mine drainage increased as the initial pH was reduced. The sulfate removal increased from 38.5 ± 3.7% to 52.2 ± 3%, while the removal of organic matter started at 91.7 ± 2.4% and ended at 99 ± 1%. These results indicate that the sulfate reducing bacteria (SRB) community adapted to lower pH values. The metal removal observed was 88 ± 7% for iron, 98.0 ± 0.5% for zinc and 99 ± 1% for copper. At this stage, an increase in the sulfate removal was observed, which reaches up to 82.2 ± 5.8%. The kinetic parameters for sulfate removal were 0.22 ± 0.04 h(-1) with Fe, 0.26 ± 0.04 h(-1) with Fe and Zn and 0.44 ± 0.04 h(-1) with Fe, Zn, and Cu.

Effects of acidic water, aluminum, and manganese on testicular steroidogenesis in Astyanax altiparanae.

Metals can influence the gonadal steroidogenesis and endocrine systems of fish, thereby affecting their reproduction. The effects of aluminum and manganese in acidic water were investigated on steroidogenesis in sexually mature male Astyanax altiparanae. Whether mature male fish recover from the effects of metals in metal-free water was also assessed. The fish were exposed to 0.5 mg L(-1) of isolated or combined aluminum and manganese in acidic pH (5.5) to keep the metals bioavailable. The fish underwent 96 h of acute exposure, and samples were taken 24 and 96 h after the beginning of the experiment. The fish were then maintained in metal-free water for 96 h. Plasma levels of testosterone, 11-ketotestosterone, 17ß-estradiol, and cortisol were measured. Acidic water increased the plasma concentration of testosterone and 11-ketotestosterone. Aluminum increased the testosterone levels after 96 h of exposure. Manganese increased the 17ß-estradiol levels after 24 h of exposure and maintained at high levels until the end of the experiment. With the exception of acidic pH, which increased cortisol levels after 24 h of exposure, no changes were observed in this corticosteroid during the acute experiment. Aluminum and manganese together also altered steroid levels but without a standard variation. The fish recovered from the effects of most exposure conditions after 96 h in metal-free water. A. altiparanae could use reproductive tactics to trigger changes in testicular steroidogenesis by accelerating spermatogenesis and spermiogenesis, which may interfere with their reproductive dynamics.

Treatment of patients with uric acid stones.

Uric acid nephrolithiasis and unduly acidic urinary pH are both considered a renal manifestation of insulin resistance but the underlying mechanisms for the development of low urinary pH and the propensity for uric acid stone formation are not completely elucidated. Nevertheless, excessive dietary acid intake, increased endogenous acid production and/or defective NH4+ excretion play an important role, among other factors. The main principles of therapy for uric acid nephrolithiasis are aimed at urinary alkalinization through diet modification or pharmacologic agents, increase of urinary volume, and less importantly at the reduction of uric acid excretion.

The use of plant-derived bioactive compounds to target cancer stem cells and modulate tumor microenvironment.

In the last decades cancer has been considered as an epigenetic dysfunction, given the profound role of diet and lifestyle in cancer prevention and the determination of cancer risk. A plethora of recent publications have addressed the specific role of several environmental factors, such as nutritional habits, behavior, stress and toxins in the regulation of the physiological and cancer epigenome. In particular, plant-derived bioactive nutrients have been seen to positively affect normal cell growth, proliferation and differentiation and also to revert cancer related epigenetic dysfunctions, reducing tumorigenesis, preventing metastasis and/or increasing chemo and radiotherapy efficacy. Moreover, virtually all cancer types are characterized by the presence of cancer stem cell (CSC) subpopulations, residing in specific hypoxic and acidic microenvironments, or niches, and these cells are currently considered responsible for tumor resistance to therapy and tumor relapse. Modern anti-cancer strategies should be designed to selectively target CSCs and modulate the hypoxic and acidic tumor microenvironment, and, to this end, natural bioactive components seem to play a role. This review aims to discuss the effects elicited by plant-derived bioactive nutrients in the regulation of CSC self-renewal, cancer metabolism and tumor microenvironment.