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1.
Environ Res ; 219: 115035, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36513128

RESUMO

Recently, advanced oxidation processes (AOPs) based upon peracetic acid (PAA) with high efficiency for degrading aqueous organic contaminants have attracted extensive attention. Herein, a novel metal-free N-doped carbonaceous catalyst, namely, carbonized polyaniline (CPANI), was applied to activate PAA to degrade phenolic and pharmaceutical pollutants. The results showed that the CPANI/PAA system could effectively degrade 10 µM phenol in 60 min with low concentrations of PAA (0.1 mM) and catalyst (25 mg L-1). This system also performed well within a wide pH range of 5-9 and displayed high tolerance to Cl-, HCO3- and humic acid. The nonradical pathway [singlet oxygen (1O2)] was found to be the dominant pathway for degrading organic contaminants in the CPNAI/PAA system. Systematic characterization revealed that the graphitic N, pyridinic N, carbonyl groups (CO) and defects played the role of active sites on CPANI during the activation of PAA. The catalytic capacity of spent CPANI could be conveniently recovered by thermal treatment. The findings will be helpful for the application of metal-free carbonaceous catalyst/PAA processes in decontaminating water.


Assuntos
Peróxido de Hidrogênio , Poluentes Químicos da Água , Ácido Peracético , Metais , Oxirredução , Fenóis , Água
2.
Food Microbiol ; 110: 104164, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36462820

RESUMO

Since the first SARS-CoV-2 outbreak in Wuhan, China, there has been continued concern over the link between SARS-CoV-2 transmission and food. However, there are few studies on the viability and removal of SARS-CoV-2 contaminating food. This study aimed to evaluate the viability of SARS-CoV-2 on food matrices, depending on storage temperature, and inactivate the virus contaminating food using disinfectants. Two SARS-CoV-2 strains (L and S types) were used to contaminate lettuce, chicken, and salmon, which were then stored at 20,4 and -40 °C. The half-life of SARS-CoV-2 at 20 °C was 3-7 h but increased to 24-46 h at 4 °C and exceeded 100 h at -40 °C. SARS-CoV-2 persisted longer on chicken or salmon than on lettuce. Treatment with 70% ethanol for 1 min inactivated 3.25 log reduction of SARS-CoV-2 inoculated on lettuce but not on chicken and salmon. ClO2 inactivated up to 2 log reduction of SARS-CoV-2 on foods. Peracetic acid was able to eliminate SARS-CoV-2 from all foods. The virucidal effect of all disinfectants used in this study did not differ between the two SARS-CoV-2 strains; therefore, they could also be effective against other SARS-CoV-2 variants. This study demonstrated that the viability of SARS-CoV-2 can be extended at 4 and -40 °C and peracetic acid can inactivate SARS-CoV-2 on food matrices.


Assuntos
COVID-19 , Desinfetantes , Animais , Ácido Peracético/farmacologia , Salmão , SARS-CoV-2 , Alface , Galinhas , Etanol , Alimentos Marinhos , Desinfetantes/farmacologia
3.
Water Res ; 229: 119462, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36516559

RESUMO

Activation of peracetic acid (PAA) to generate powerful oxidizing species has become a promising advanced oxidation processes (AOPs) in wastewater treatment, yet the development of low-cost and high-performance activators is still a primary challenge. Herein, a range of Co-Mn spinel oxides (Co3-xMnxO4) with varying levels of Co and Mn were successfully elaborated, in which Co1.1Mn1.9O4 exhibited remarkable performance in PAA activation, outperforming most reported heterogeneous catalysts. Extensive quenching experiments and electron spin resonance (ESR) analysis indicated that acetylperoxyl radical (CH3C(O)OO●) was the predominated oxidizing species responsible for sulfamethoxazole (SMX) degradation. Density functional theory (DFT) calculations revealed that doping with Mn not only promoted the electron transfer and accelerated reduction of Co(III) to Co(II), but also lowered the energy barrier for PAA activation. Moreover, the prominent chemisorption and activation of PAA with Co1.1Mn1.9O4 was also benefitted from the significant role of Mn in optimizing the distribution of bonding and antibonding states on Co 3d orbitals. Unexpectedly, high levels of Cl-greatly facilitated SMX degradation due to the mass production of HOCl from the chain reactions of various radicals with Cl-. This work provides new insights into bimetallic activation of PAA, and the knowledge obtained will further advance the application of PAA-based AOPs.


Assuntos
Óxidos , Poluentes Químicos da Água , Ácido Peracético , Antibacterianos , Oxirredução , Sulfanilamida , Sulfametoxazol , Peróxido de Hidrogênio
4.
Sci Total Environ ; 862: 160719, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36481134

RESUMO

Succinic acid (SA) has been produced from rice straw (RS) and sugarcane bagasse (SB) as low-cost feedstocks in this study through sequential peracetic acid (PA) and alkaline peroxide (AP) pretreatment assisted by ultrasound and pre-hydrolysis followed by simultaneous saccharification and fermentation (PSSF). The effect of yeast extract (YE) concentration, inoculum concentration, and biomass type on SA production was investigated. The results showed that SA production from RS and SB was significantly affected by the YE concentration. Final concentration and yield of SA produced were significantly increased along with the increasing of YE concentration. Moreover, inoculum concentration significantly affected the SA production from SB. Higher inoculum concentration led to higher SA production. On the other hand, SA production from RS was not significantly affected by the inoculum concentration. Using RS as the feedstock, the highest SA production was achieved on the medium containing 15 g/L YE with 5 % v/v inoculum, obtaining SA concentration and yield of 3.64 ± 0.1 g/L and 0.18 ± 0.05 g/g biomass, respectively. Meanwhile, the highest SA production from SB was acquired on the medium containing 10 g/L YE with 7.5 % v/v inoculum, resulting SA concentration and yield of 5.1 ± 0.1 g/L and 0.25 ± 0.05 g/g biomass, respectively. This study suggested that RS and SB are potential to be used as low-cost feedstocks for sustainable and environmentally friendly SA production through ultrasonic-assisted PA and AP pretreatment and PSSF.


Assuntos
Oryza , Saccharum , Celulose/metabolismo , Ácido Succínico , Oryza/metabolismo , Saccharum/metabolismo , Fermentação , Ácido Peracético , Hidrólise
5.
Chemosphere ; 287(Pt 4): 132396, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34597644

RESUMO

Activating peroxides to produce active substances is the key to advanced oxidation processes (AOPs), but this usually requires energy or is accompanied by additional contaminants. In this study, diclofenac (DCF) was effectively removed by peracetic acid (PAA) in phosphate buffer (PBS). According to the results of radical scavenging experiments and electron paramagnetic resonance (EPR), hydroxyl radical (•OH) and organic radicals (i.e., CH3C(=O)OO• and CH3C(=O)O•) generated from PBS-activated PAA might be the dominant reactive species responsible for DCF degradation. At neutral pH, PBS/PAA system exhibited the best degradation efficiency on DCF. Presence of NO3-, SO42- and Cl- had little effect on the removal of DCF, while HCO3- and natural organic matter (NOM) significantly inhibited DCF degradation in PBS/PAA system, resulting in the lower degradation efficiency of DCF in natural waters than that in ultrapure water. Finally, four possible degradation pathways, including hydroxylation, formylation, dehydrogenation and dechlorination, were proposed based on the detected reaction products. This study suggests that PBS used to control solution pH should be applied cautiously in PAA-based AOPs.


Assuntos
Diclofenaco , Poluentes Químicos da Água , Peróxido de Hidrogênio , Cinética , Ácido Peracético , Fosfatos , Poluentes Químicos da Água/análise
6.
J Vis Exp ; (190)2022 12 09.
Artigo em Inglês | MEDLINE | ID: mdl-36571408

RESUMO

The presence of biofilms in the dairy industry is of major concern, as they may lead to the production of unsafe and altered dairy products due to their high resistance to most clean-in-place (CIP) procedures frequently used in processing plants. Therefore, it is imperative to develop new biofilm control strategies for the dairy industry. This protocol is aimed at evaluating the efficacy of organic peroxyacids (peracetic, perpropionic, and perlactic acids and a commercial peracetic acid-based disinfectant) for eradicating dairy biofilms using a combination of static and dynamic methods. All the disinfectants were tested on the strongest biofilm-producing bacteria in either a single or a mixed biofilm using the minimum biofilm eradication concentration (MBEC) assay, a static high-throughput screening method. A contact time of 5 min with the disinfectants at the recommended concentrations successfully eradicated both the single and mixed biofilms. Studies are currently ongoing to confirm these observations using the Center for Disease Control (CDC) biofilm reactor, a dynamic method to mimic in situ conditions. This type of bioreactor enables the use of a stainless-steel surface, which constitutes most industrial equipment and surfaces. The preliminary results from the reactor appear to confirm the efficacy of organic peroxyacids against biofilms. The combined approach described in this study may be used to develop and test new biological or chemical formulations for controlling biofilms and eradicating microorganisms.


Assuntos
Desinfetantes , Desinfetantes/farmacologia , Desinfetantes/química , Ácido Peracético/farmacologia , Biofilmes , Aço Inoxidável
7.
Water Res ; 227: 119346, 2022 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-36395567

RESUMO

Peracetic-acid-based advanced oxidation processes (PAA-AOPs) on metal-free catalysts have emerged as charming strategies for water contaminant removal. However, the involved reactive species and their corresponding active sites are ambiguous. Herein, using carbon nanotube (CNT) as a model carbocatalyst, we demonstrated that, under neutral conditions, the CNT-PAA* complex was the dominant reactive species to oxidize phenolic compounds via electron-transfer process (ETP), whereas the surface-bound hydroxyl radicals (·OHsurface) played a minor role on the basis of quenching and electrochemical tests as well as Raman spectroscopy. More importantly, the experimental and density functional theory (DFT) calculation results collaboratively proved that the active site for ETP was the sp2-hybridized carbon on the CNT bulk, while that for radical generation was the edge-located hydroxyl group (C-OH), which lowered the energy barrier for cleaving the O-O bond in CNT-PAA* complex. We further discerned the oxidation kinetic constants (koxid) of different pollutants from the apparent kinetic constants in CNT/PAA system. The significant negative linear correlation between lnkoxid and half-wave potential of phenolic compounds suggests that the pollutants with a lower one-electron oxidation potential (i.e., stronger electron-donating ability) are more easily oxidized. Overall, this study scrutinizes the hybrid radical and non-radical mechanism and the corresponding active sites of the CNT/PAA system, providing insights into the application of PAA-AOPs and the development of ETP in the remediation of emerging organic pollutants.


Assuntos
Poluentes Ambientais , Nanotubos de Carbono , Ácido Peracético , Domínio Catalítico , Radical Hidroxila/química , Cinética , Nanotubos de Carbono/química , Fenóis/química
8.
ASAIO J ; 68(11): 1414-1418, 2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-36326706

RESUMO

The practice of dialyzer reuse is common in developing countries. One essential technique for safe dialyzer reprocessing is to remove disinfectants properly to the recommended standards before treatment initiation, using dialysis machine recirculation with ultrafiltration. This study was conducted to identify the most effective time for carrying out this procedure, and the factors affecting it. We studied 420 high-flux dialyzers with three different membrane types: FB210U (cellulose triacetate), F80S (polysulfone), and Elisio-210HR (polyethersulfone) at four reused cycles (5th, 10th, 15th, and 19th). Peracetic acid was used as the disinfectant at a concentration of 0.16%. The total cell volume (TCV) and clot inspection grade of the reused dialyzer were recorded before the procedure. The optimal time for disinfectant removal was independently determined by two observers using the residual peroxide strip test of the ultrafiltrate. We observed that disinfectant removal was dependent on the recirculation time and became undetectable at 5 minutes. The type of dialyzer had a significant effect on the effective recirculation time (shortest for FB210U followed by Elisio-210HR and F80S; p < 0.001), but the reused number, TCV, and clot inspection grade did not. It is conceivable that the dialyzer membrane type might affect peracetic acid removal. In conclusion, the interval for carrying out dialysis machine recirculation with ultrafiltration depends on the dialyzer type, and 5 minutes is the optimal time for the operation. This result can be implemented to improve further practice in dialyzer reprocessing.


Assuntos
Desinfetantes , Ácido Peracético , Desinfetantes/farmacologia , Ultrafiltração , Reutilização de Equipamento , Diálise Renal/métodos , Membranas Artificiais
9.
Pol J Microbiol ; 71(3): 353-358, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-36185021

RESUMO

Research on the susceptibility of the spores of anaerobic bacteria such as Clostridium sporogenes or Clostridioides difficile is vital for assessing the sporicidal activity of disinfectants. The diverse susceptibility of anaerobic bacteria spores may lead to different disinfection parameters being determined by laboratories that prepare spore suspensions to test sporicidal effectiveness. The tests were performed using the suspension method according to PN-EN 13704:2018-09. In order to assess the susceptibility of the C. sporogenes spores, the criterion established for the C. difficile ribotype 027 spores was used in accordance with PN­EN 17126:2019-01. The susceptibility of the C. sporogenes spores to glutardialdehyde corresponded to the susceptibility ranges established for the C. difficile ribotype 027 spores. The C. sporogenes spore suspension was susceptible to low concentrations of peracetic acid (0.01%). A disinfectant containing peracetic acid as the active substance showed high sporicidal activity at a low concentration (1%), a short contact time (15 minutes), and a high organic load (3.0 g/l bovine albumin + 3.0 ml/l sheep erythrocytes), as compared to a disinfectant with glutardialdehyde, which was sporicidal at a higher concentration (2.5%), at a longer contact time (60 minutes) and lower organic conditions (3.0 g/l bovine albumin). There is a need to define the minimum susceptibility criteria for the C. sporogenes spores to the reference substances most often found in disinfectants with sporicidal activity. Excessive susceptibility of the C. sporogenes spores to reference substances may result in low-performance parameters of disinfection products with sporicidal activity and lead to ineffective disinfection in practice.


Assuntos
Clostridioides difficile , Desinfetantes , Animais , Clostridium , Desinfetantes/farmacologia , Glutaral , Ácido Peracético , Soroalbumina Bovina , Ovinos , Esporos Bacterianos , Suspensões
10.
Int J Food Microbiol ; 383: 109958, 2022 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-36240604

RESUMO

In the present study, bacterial-derived antimicrobial agents included 5 mM reuterin combined with either 103.91 mM lactic acid (RL) or 0.08 µM microcin J25 (RJ) were evaluated for their effects on the microbiota and sensory attributes of raw chicken legs. Peracetic acid (13.67 mM), a conventional chemical commonly used in the poultry industry, was used as a positive control to compare efficacy. The chicken legs were sprayed with antimicrobial solutions and aerobically stored at 4 °C for 10 days. The RL treatment maintained the total viable count below the limit of 7 log CFU/g until the 8th day. Therefore, compared to the nontreated group, shelf-life was extended by 3 days in the RL treated group. The RJ treatment extended the shelf-life to 7 days, which is similar to what was achieved with the use of peracetic acid. Based on culture-independent amplicon sequencing, the RL and RJ treatments affected the microbial community on the chicken legs, inducing a delay in the increase of Pseudomonas, Psychrobacter and Carnobacterium while decreasing of Shigella. Significant decreases in sensory scores occurred in the nontreated group, while slight changes occurred in the combinations treated groups over the same period. Overall, sensory property scores for chicken legs treated with RL and RJ remained higher (P < 0.05) than those treated with peracetic acid or without antimicrobial agents. The antimicrobial combinations delayed the deterioration of sensory attributes throughout the storage period. These results suggest that RL and RJ provide a promising natural-sourced antimicrobial approach to control the growth of spoilage microorganisms on chicken legs.


Assuntos
Desinfetantes , Microbiota , Animais , Galinhas/microbiologia , Conservação de Alimentos/métodos , Ácido Peracético/farmacologia , Bactérias , Desinfetantes/farmacologia , Ácido Láctico/farmacologia , Contagem de Colônia Microbiana , Carne/microbiologia
11.
Molecules ; 27(19)2022 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-36234896

RESUMO

The stubborn and complex structure of lignocellulose hinders the valorization of each component of cellulose, hemicellulose, and lignin in the biorefinery industries. Therefore, efficient pretreatment is an essential and prerequisite step for lignocellulose biorefinery. Recently, a considerable number of studies have focused on peroxyacetic acid (PAA) pretreatment in lignocellulose fractionation and some breakthroughs have been achieved in recent decades. In this article, we aim to highlight the challenges of PAA pretreatment and propose a roadmap towards lignocellulose fractionation by PAA for future research. As a novel promising pretreatment method towards lignocellulosic fractionation, PAA is a strong oxidizing agent that can selectively remove lignin and hemicellulose from lignocellulose, retaining intact cellulose for downstream upgrading. PAA in lignocellulose pretreatment can be divided into commercial PAA, chemical activation PAA, and enzymatic in-situ generation of PAA. Each PAA for lignocellulose fractionation shows its own advantages and disadvantages. To meet the theme of green chemistry, enzymatic in-situ generation of PAA has aroused a great deal of enthusiasm in lignocellulose fractionation. Furthermore, mass balance and techno-economic analyses are discussed in order to evaluate the feasibility of PAA pretreatment in lignocellulose fractionation. Ultimately, some perspectives and opportunities are proposed to address the existing limitations in PAA pretreatment towards biomass biorefinery valorization. In summary, from the views of green chemistry, enzymatic in-situ generation of PAA will become a cutting-edge topic research in the lignocellulose fractionation in future.


Assuntos
Lignina , Ácido Peracético , Biomassa , Celulose , Lignina/química , Oxidantes , Ácido Peracético/farmacologia
12.
Molecules ; 27(19)2022 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-36234920

RESUMO

Advanced oxidation processes (AOPs) demonstrate great micropollutant degradation efficiency. In this study, CuFe2O4 was successfully used to activate peracetic acid (PAA) to remove Rhodamine B. Acetyl(per)oxyl radicals were the dominant species in this novel system. The addition of 2,4-hexadiene (2,4-HD) and Methanol (MeOH) significantly inhibited the degradation efficiency of Rhodamine B. The ≡Cu2+/≡Cu+ redox cycle dominated PAA activation, thereby producing organic radicals (R-O˙) including CH3C(O)O˙ and CH3C(O)OO˙, which accounted for the degradation of Rhodamine B. Increasing either the concentration of CuFe2O4 (0-100 mg/L) or PAA (10-100 mg/L) promoted the removal efficiency of this potent system. In addition, weakly acid to weakly alkali pH conditions (6-8) were suitable for pollutant removal. The addition of Humid acid (HA), HCO3-, and a small amount of Cl- (10-100 mmol·L-1) slightly inhibited the degradation of Rhodamine B. However, degradation was accelerated by the inclusion of high concentrations (200 mmol·L-1) of Cl-. After four iterations of catalyst recycling, the degradation efficiency remained stable and no additional functional group characteristic peaks were observed. Taking into consideration the reaction conditions, interfering substances, system stability, and pollutant-removal efficiency, the CuFe2O4/PAA system demonstrated great potential for the degradation of Rhodamine B.


Assuntos
Ácido Peracético , Poluentes Químicos da Água , Álcalis , Peróxido de Hidrogênio , Metanol , Oxirredução , Rodaminas
13.
Molecules ; 27(20)2022 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-36296611

RESUMO

Chlorinated compounds are usually applied in vegetable sanitization, but there are concerns about their application. Thus, this study aimed to evaluate ultrasound (50 kHz), acetic acid (1000; 2000 mg/L), and peracetic acid (20 mg/L) and their combination as alternative treatments to 200 mg/L sodium dichloroisocyanurate. The overall microbial, physicochemical, and nutritional quality of kale stored at 7 °C were assessed. The impact on Salmonella enterica Typhimurium was verified by plate-counting and scanning electron microscopy. Ultrasound combined with peracetic acid exhibited higher reductions in aerobic mesophiles, molds and yeasts, and coliforms at 35 °C (2.6; 2.4; 2.6 log CFU/g, respectively). Microbial counts remained stable during storage. The highest reduction in Salmonella occurred with the combination of ultrasound and acetic acid at 1000 mg/L and acetic acid at 2000 mg/L (2.8; 3.8 log CFU/g, respectively). No synergistic effect was observed with the combination of treatments. The cellular morphology of the pathogen altered after combinations of ultrasound and acetic acid at 2000 mg/L and peracetic acid. No changes in titratable total acidity, mass loss, vitamin C, or total phenolic compounds occurred. Alternative treatments presented equal to or greater efficacies than chlorinated compounds, so they could potentially be used for the decontamination of kale.


Assuntos
Brassica , Compostos Clorados , Desinfetantes , Ácido Peracético/farmacologia , Ácido Acético/farmacologia , Desinfetantes/farmacologia , Descontaminação , Desinfecção , Microbiologia de Alimentos , Contagem de Colônia Microbiana , Salmonella typhimurium , Ácido Ascórbico/farmacologia , Cloro/farmacologia , Cloro/química , Manipulação de Alimentos
14.
Water Res ; 225: 119176, 2022 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-36191527

RESUMO

High microwave-response cobalt-substituted manganese ferrite (CMFO-0.5) was successfully synthesized as a heterogeneous catalyst for efficient peracetic acid (PAA) activation and tetracycline hydrochloride (TCH) degradation with singlet oxygen (1O2) as the dominated reactive oxidized species (ROS). The removal efficiency of TCH could reach 98.16% within 6 min under microwave irradiation when the CMFO-0.5 was added at 20 mg/L. It's found that the Co substitution could produce the oxygen vacancies (OVs), improve the microwave (MW) absorbing performance and enhance the internal electron transfer efficiency of materials. The phenomenon why 1O2 as the dominated ROS rather than hydroxyl radical (•OH) and organic radicals (R-O•) would be explained by the following aspects: the oxygen adsorbed on the OVs can accept the electron transformed from PAA to form superoxide radical (•O2-), which will disproportionate to form 1O2; the energy generated by the non-thermal effect of MW can dissociate PAA to generate peroxy-group for 1O2 generation. Furthermore, the possible TCH degradation pathways were proposed based on DFT theory calculations and product identification, and the toxicity predictions of the degradation products were also performed by the Ecological Structure-Activity Relationship Model (ECOSAR) software. Additionally, the decrease of acute toxicity of treated TCH, excellent stability and strong resistance towards water matrix fully demonstrate the superiority of the proposed system for practical application in wastewater treatment.


Assuntos
Ácido Peracético , Tetraciclina , Micro-Ondas , Oxigênio , Radical Hidroxila , Oxigênio Singlete , Espécies Reativas de Oxigênio , Superóxidos , Oxirredução , Cobalto , Água
15.
Analyst ; 147(21): 4838-4844, 2022 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-36128870

RESUMO

Characterization of glycerophospholipid isomers is of significant importance as they play different roles in physiological and pathological processes. In this work, we present a novel and bifunctional derivatization method utilizing Mn(II)-catalyzed epoxidation to simultaneously identify carbon-carbon double bond (CC bond)- and stereonumbering (sn)-positional isomers of phosphatidylcholine. Mn(II) coordinates with picolinic acid and catalyzes epoxidation of unsaturated lipids by peracetic acid. Collision-induced dissociation (CID) of the epoxides generates diagnostic ions that can be used to locate CC bond positions. Meanwhile, CID of Mn(II) ion-lipid complexes produces characteristic ions for determination of sn positions. This bifunctional derivatization takes place in seconds, and the diagnostic ions produced in CID are clear and easy to interpret. Moreover, relative quantification of CC bond-and sn-positional isomers was achieved. The capability of this method in identifying lipids at multiple isomer levels was shown using lipid standards and lipid extracts from complex biological samples.


Assuntos
Glicerofosfolipídeos , Ácido Peracético , Fosfatidilcolinas/química , Íons/química , Compostos de Epóxi , Carbono , Catálise
16.
Front Immunol ; 13: 948897, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36090977

RESUMO

Treatment development for parasitic infestation is often limited to disease resolution as an endpoint response, and physiological and immunological consequences are not thoroughly considered. Here, we report the impact of exposing Atlantic salmon affected with amoebic gill disease (AGD) to peracetic acid (PAA), an oxidative chemotherapeutic. AGD-affected fish were treated with PAA either by exposing them to 5 ppm for 30 min or 10 ppm for 15 min. Unexposed fish from both infected and uninfected groups were also included. Samples for molecular, biochemical, and histological evaluations were collected at 24 h, 2 weeks, and 4 weeks post-treatment. Behavioral changes were observed during PAA exposure, and post-treatment mortality was higher in the infected and PAA treated groups, especially in 10 ppm for 15 min. Plasma indicators showed that liver health was affected by AGD, though PAA treatment did not exacerbate the infection-related changes. Transcriptome profiling in the gills showed significant changes, triggered by AGD and PAA treatments, and the effects of PAA were more notable 24 h after treatment. Genes related to immune pathways of B- and T- cells and protein synthesis and metabolism were downregulated, where the magnitude was more remarkable in 10 ppm for 15 min group. Even though treatment did not fully resolve the pathologies associated with AGD, 5 ppm for 30 min group showed lower parasite load at 4 weeks post-treatment. Mucous cell parameters (i.e., size and density) increased within 24 h post-treatment and were significantly higher at termination, especially in AGD-affected fish, with some treatment effects influenced by the dose of PAA. Infection and treatments resulted in oxidative stress-in the early phase in the gill mucosa, while systemic reactive oxygen species (ROS) dysregulation was evident at the later stage. Infected fish responded to elevated circulating ROS by increasing antioxidant production. Exposing the fish to a crowding stress revealed the interference in the post-stress responses. Lower cortisol response was displayed by AGD-affected groups. Collectively, the study established that PAA, within the evaluated treatment protocols, could not provide a convincing treatment resolution and, thus, requires further optimization. Nonetheless, PAA treatment altered the mucosal immune and stress responses of AGD-affected Atlantic salmon, shedding light on the host-parasite-treatment interactions. .


Assuntos
Parasitos , Salmo salar , Amebíase , Animais , Doenças dos Peixes , Membrana Mucosa , Oxidantes , Ácido Peracético , Espécies Reativas de Oxigênio
17.
Oper Dent ; 47(5): E211-E221, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-36121721

RESUMO

PURPOSE: The aim of this study was to evaluate the effects of a new irrigant solution on the post space cleaning and the adhesive resistance of fiber posts. METHODS AND MATERIALS: Eighty roots of bovine teeth were randomly allocated into eight groups (n=10 for each group). Evaluations were performed in two different time points for each irrigant. The irrigants included a control group with distilled water (DW), 2.5% NaOCl and 17% EDTA (SH), 1% peracetic acid (PA), and 5% boric acid and 1% citric acid (EX). The time points were 24 hours (I-immediate) and 6 months (D-delayed). The push-out test was performed using a universal testing machine with a 5 kN load cell operating at a crosshead speed of 0.5 mm/minute. The dentinal cementation system was analyzed using a laser confocal microscope (LSM5, Zeiss, Jena, Germany), and incidence of residue on radicular dentin was evaluated by scanning electron microscopy (SEM). The incidence of residue was evaluated by the Kruskal-Wallis test and push-out bond strength and dentin penetrability were evaluated via a one-way analysis of variance (ANOVA) and Tukey tests (α=0.05). RESULTS: The EX irrigation protocol demonstrated the lowest incidence of residue on the dentin surface (p<0.05), independently of the evaluated third. In the cervical and the middle post thirds, EXI, EXD, SHI, and SHD groups exhibited similar push-out bond strength values (p>0.05). EXI, EXD, PAI, and PAD exhibited the greatest dentinal penetrability of the cementation system in all the post thirds (p<0.05). CONCLUSIONS: A solution containing 5% boric acid and 1% citric acid can be a promising irrigant for radicular post space cleaning. It has adequate potential for cleaning the dentin surface without interfering with the adhesive interface between the dentin and the cementation system.


Assuntos
Colagem Dentária , Técnica para Retentor Intrarradicular , Animais , Ácidos Bóricos , Bovinos , Ácido Cítrico/análise , Ácido Cítrico/farmacologia , Colagem Dentária/métodos , Cimentos Dentários/uso terapêutico , Cavidade Pulpar , Dentina , Dissulfetos , Ácido Edético/química , Teste de Materiais , Ácido Peracético/análise , Ácido Peracético/farmacologia , Cimentos de Resina/química , Cimentos de Resina/uso terapêutico , Irrigantes do Canal Radicular/análise , Irrigantes do Canal Radicular/química , Irrigantes do Canal Radicular/uso terapêutico , Tionas , Água
18.
Fish Shellfish Immunol ; 130: 612-623, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36150413

RESUMO

The present study investigated the involvement of key molecular regulators of oxidative stress in amoebic gill disease (AGD), a parasitic infestation in Atlantic salmon. In addition, the study evaluated how these molecular biomarkers responded when AGD-affected fish were exposed to a candidate chemotherapeutic peracetic acid (PAA). Atlantic salmon were experimentally infected with the parasite Neoparameoba perurans, the causative agent of AGD, by bath exposure and after 2 weeks, the fish were treated with three commercial PAA products (i.e., Perfectoxid, AquaDes and ADDIAqua) at a dose of 5 ppm. Two exposure durations were evaluated - 30 min and 60 min. Sampling was performed 24 h and 2 weeks after PAA treatment (equivalent to 2- and 4-weeks post infection). At each sampling point, the following parameters were evaluated: gross gill pathology, gill parasitic load, plasma reactive oxygen species (ROS) and total antioxidant capacity (TAC), histopathology and gene expression profiling of genes with key involvement in oxidative stress in the gills and olfactory organ. AGD did not result in systemic oxidative stress as ROS and TAC levels remained unchanged. There were no clear patterns of AGD-mediated regulation of the oxidative stress biomarkers in both the gills and olfactory organ; significant changes in the expression were mostly related to time rather than infection status. However, the expression profiles of the oxidative stress biomarkers in AGD-affected salmon, following treatment with PAA, revealed that gills and olfactory organ responded differently - upregulation was prominent in the gills while downregulation was more frequent in the olfactory organ. The expression of catalase, glutathione S-transferase and thioredoxin reductase 2 was significantly affected by the treatments, both in the gills and olfactory organ, and these alterations were influenced by the duration of exposure and PAA product type. Parasitic load in the gills did significantly increase after treatment regardless of the product and exposure duration; the parasite was undetectable in some fish treated with AquaDes for 30 mins. However, PAA treated groups for 30 min showed lower macroscopic gill scores than the infected-untreated fish. Histology disclosed the classic pathological findings such as multifocal hyperplasia and increased number of mucous cells in AGD-affected fish. Microscopic scoring of gill injuries showed that AGD-infected-PAA-treated fish had lower scores, however, an overall trend could not be established. The morphology and structural integrity of the olfactory organ were not significantly altered by parasitism or PAA treatment. Collectively, the results indicate that AGD did not affect the systemic and mucosal oxidative status of Atlantic salmon. However, such a striking profile was changed when AGD-affected fish were exposed to oxidative chemotherapeutics. Moreover, the gills and olfactory organ demonstrated distinct patterns of gene expression of oxidative stress biomarkers in AGD-infected-PAA-treated fish. Lastly, PAA treatment did not fully resolve the infection, but appeared not to worsen the mucosal health either.


Assuntos
Amebíase , Doenças dos Peixes , Parasitos , Salmo salar , Amebíase/tratamento farmacológico , Amebíase/parasitologia , Amebíase/veterinária , Animais , Antioxidantes/metabolismo , Biomarcadores/metabolismo , Catalase/metabolismo , Doenças dos Peixes/genética , Brânquias/metabolismo , Glutationa Transferase/metabolismo , Estresse Oxidativo , Ácido Peracético , Espécies Reativas de Oxigênio/metabolismo , Salmo salar/genética , Salmo salar/metabolismo , Tiorredoxina Redutase 2/metabolismo
19.
Environ Pollut ; 313: 120170, 2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-36115488

RESUMO

Peracetic acid (PAA) as an emerging oxidative has been concerned increasingly due to its high oxidation capacity and low byproducts formation potential. This study was to investigate the oxidation of sulfamethazine (SMZ) by PAA activated with activated biochar (ABC) after thermal modification. The results demonstrated that PAA could be effectively activated by ABC to degrade SMZ in a wide pH range (3-9), which followed the pseudo-second-order kinetics (R2 > 0.99). Both non-radicals (singlet oxygen) and free radicals (alkoxy radicals, hydroxyl radicals) existed in the ABC/PAA system, and the degradation of SMZ was dominated by singlet oxygen. Humic acid (HA), SO42- and HCO3- slightly inhibited the degradation of SMZ in the ABC/PAA process, while Cl- and Br- promoted the degradation of SMZ. The cleavage of S-N, S-C bond, and SO2 extraction reaction rearrangement was the main oxidation process of SMZ. Meanwhile, the results of the ECOSAR program showed that the acute toxicity of most by-products was significantly reduced compared to SMZ, which revealed the potential applicability of the ABC/PAA process in the treatment of antibiotics pollution and their detoxification.


Assuntos
Sulfametazina , Poluentes Químicos da Água , Antibacterianos , Carvão Vegetal , Substâncias Húmicas , Ácido Peracético/toxicidade , Espécies Reativas de Oxigênio , Oxigênio Singlete , Sulfametazina/química , Sulfametazina/toxicidade , Poluentes Químicos da Água/química , Poluentes Químicos da Água/toxicidade
20.
Orthop Surg ; 14(10): 2657-2668, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36054510

RESUMO

OBJECTIVE: Pre-implantation sterilization procedures for tendons are important measures to reduce the risk of disease transmission, however these procedures may compromise tendon microarchitecture and biomechanical properties to varying degrees. We explore the effects of different sterilization procedures on the micro-histology, biomechanical strength and biochemical properties of human tendon allografts in vitro study. METHODS: The tendon allografts were harvested from cadaveric donors after the donors were serologically screened by antibody or nucleic acid testing of infectious agents. All samples were divided into five groups, which were fresh-frozen group (control group), 15 kGy gamma irradiation group, 25 kGy gamma irradiation group, 70% ethanol group, and peracetic acid-ethanol group. Each group included 10 tendons for testing. Histological staining and transmission electron microscopy were applied to observe the internal structure and arrangement of tendon collagen fibers, while the machine learning classifier was trained to distinguish the darker cross-sections of collagen fibers and brighter backgrounds of the electron micrograph to detect the distribution of diameters of tendon collagen fibers. The viscoelasticity, mechanical properties and material properties of tendon allografts were examined to detect the influence of different intervention factors on the biomechanical properties of tendons. RESULTS: Histological staining and transmission electron microscopy showed that the structure of fresh-frozen tendons was similar to the structures of other experimental groups, and no obvious fiber disorder or delamination was observed. In the uniaxial cyclic test, the cyclic creep of 25 kGy irradiation group (1.5%) and peracetic acid-ethanol group (1.5%) were significantly lower than that of the control group (3.6%, F = 1.52, P = 0.039) while in the load-to-failure test, the maximum elongation and maximum strain of the peracetic acid-ethanol group were significantly higher than those of the control group (F = 4.60, P = 0.010), and there was no significant difference in other biomechanical indicators. According to the experimental results of denatured collagen, it could be seen that no matter which disinfection procedure was used, the denaturation of the tendon sample would be promoted (F = 1.97, P = 0.186), and high-dose irradiation seemed to cause more damage to collagen fibers than the other two disinfection procedures (296.2 vs 171.1 vs 212.9 µg/g). CONCLUSION: Biomechanical experiments and collagen denaturation tests showed that 15 kGy gamma irradiation and 70% ethanol can preserve the biomechanical strength and biochemical properties of tendons to the greatest extent, and these two sterilization methods are worthy of further promotion.


Assuntos
Ácidos Nucleicos , Ácido Peracético , Aloenxertos , Fenômenos Biomecânicos , Etanol , Raios gama , Humanos , Ácido Peracético/farmacologia , Esterilização/métodos , Tendões
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