Pseudomonas aeruginosa strain PA01 impairs enzymes of the phosphotransfer network in the gills of Rhamdia quelen

Effects of Melissa officinalis L. Essential Oil in Comparison with Anaesthetics on Gill Tissue Damage, Liver Metabolism and Immune Parameters in Sea Bass (Lateolabrax maculatus) during Simulated Live Transport

In the current study, Melissa officinalis L. essential oil (MOEO), a novel sedative and anaesthetic, was employed in transport water to obtain a lower stress effect and higher survival rate for live marine fish. The effect of MOEO and various types of anaesthetics, administered at a low temperature on gill morphology, liver function and immunological parameters of living sea bass (Lateolabrax maculatus) subjected to transport stress, was evaluated to optimize the anaesthetic and sedative concentrations during live sea bass transport. Light microscopy and scanning electron microscopy of sea bass, subjected to simulated live transport for 72 h, demonstrated that the changes in the morphological characteristics of gill tissue treated with 40 mg/L MOEO (A3 group) were minimal in comparison to those observed in untreated sea bass. The results of pyruvate kinase (PK), phosphofructokinase (PFK), hexokinase (HK), hepatic glycogen (Gly), superoxide dismutase (SOD), lipid peroxides (MDA) and Caspase-3 assays indicated that the glycolysis rate, energy consumption, lipid peroxidation and hepatocyte apoptosis were the lowest in the A3 group. The values of the two immune parameters, lysozyme (LZM) and fish immunoglobulin M (IgM), indicated the strongest immunity ability in the A3 group. After 12 h recovery, sea bass treated with 30 mg/L MS-222 (B group) displayed a 100% survival rate, sea bass treated with 20 mg/L (A2 group) and 40 mg/L (A3 group) MOEO displayed a 96% survival rate, sea bass treated with 20 mg/L eugenol (C group) had a 94% survival rate, and untreated sea bass (CK group) had a 50% survival rate. Therefore, the addition MOEO to the transport water had anaesthetic and sedative effects similar to MS-222 and eugenol. The results confirmed that the addition of MOEO to the transport water could reduce tissue damage, energy metabolism, and the oxidative stress response in sea bass during transport.

Effects of thymol supplementation on performance, mortality and branchial energetic metabolism in grass carp experimentally infected by Aeromonas hydrophila

We determined whether thymol supplementation of would minimize the negative effects of Aeromonas hydrophila infection on branchial energy metabolism, weight loss and mortality in grass carp (Ctenopharyngodon idella). We found that the infected fish all died, while 62.5% of those supplemented with 100 mg/kg thymol survived. Cytosolic and mitochondrial creatine kinase (CK) activities, as well as adenylate kinase (AK) and pyruvate kinase (PK) activities were significant lower in gills of A. hydrophila-infected fish than those of the control group, and adenosine triphosphate (ATP) levels were significant lower in the infected group. Finally, branchial reactive oxygen species (ROS) were significant higher in A. hydrophila-infected fish than in the control group. Supplementation with 100 and 300 mg thymol/kg diet prevented inhibition of branchial cytosolic and mitochondrial CK activities caused by infection, and also inhibited the reduction of branchial ATP levels. Supplementation with 100, 200 and 300 mg thymol/kg prevented the inhibition of branchial AK and PK activities induced by aeromonosis. Supplementation of 100 mg thymol/kg prevented weight loss after A. hydrophila infection. These data suggest that supplementation with 100 mg thymol/kg exerts potent bactericidal properties and augments longevity. Supplementation at all concentrations of thymol prevented A. hydrophila-induced branchial bioenergetics; nevertheless, higher concentrations were associated with side-effects.

Impact of colibacillosis on production in laying hens associated with interference of the phosphotransfer network and oxidative stress

The objective of this study was to evaluate the productive impact of colibacillosis on laying hens and to investigate whether energetic metabolism and oxidative stress were involved in the pathogenesis of the disease. An experimental shed containing 270 laying hens of the Hy-Line lineage (32 weeks old) presented approximately 40% daily laying, and many birds presented with diarrhea and apathy followed by death. Necropsy revealed macroscopic lesions compatible with colibacillosis and infectious agent Escherichia coli was isolated from fecal samples of all birds in the infected group, as well as from tissue (ovary, liver and peritoneum). Sixteen chickens were selected for this study, divided into two groups: Control (animals without clinical alterations) and infected (with diarrhea and apathetic). E. coli isolates were subjected to the antimicrobial susceptibility testing according to the methodology approved by CLSI, 2018. This testing showed sensitivity to gentamicin, amoxicillin, norfloxacin and colistin. It was then determined that laying hens would be treated with norfloxacin (15 mg/kg) diluted in water offered at will to the birds for three days. Blood collections were performed via brachial vein after the diagnosis of E. coli (before starting treatment) and seven days after treatment. Three debilitated chickens died on the second day after initiating therapy. Before treatment, birds with clinical signs had higher levels of lipoperoxidation (LPO) and activities of antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx) than in the control group (asymptomatic animals). After treatment, LPO levels remained higher in birds that had clinical disease (infected group), whereas the activity of SOD and GPx enzymes did not differ between groups. Activity levels of creatine kinase (CK) and pyruvate kinase (PK) were higher in the group of chickens with clinical disease before treatment. Post-treatment, no differences were observed between groups in terms of CK; however, PK activity remained high in these animals. In the hens that died, there were lesions characteristic of avian colibacillosis, with ovary involvement, explaining the low laying activity of the birds at their peak of production. For 10 days after starting treatment, the percentage of laying increased to 90%. Therefore, we conclude that colibacillosis interferes with the phosphotransfer network by stimulating ATP production, in addition to causing oxidative stress of the birds during laying, that negatively affects health and productive efficiency.

Oxidative stress mediated the inhibition of cerebral creatine kinase activity in silver catfish fed with aflatoxin B1-contaminated diet

Aflatoxin B₁ (AFB₁) is an environmental toxicant and neurotoxic compound that induces the production of free radicals, causing oxidative stress. Creatine kinase (CK) is a central controller of energy metabolism in tissues with a large and fluctuating energy demand, and it is highly susceptible to inactivation by free radicals and oxidative damage. Thus, the aim of this study was to evaluate whether a diet for freshwater silver catfish (Rhamdia quelen) containing AFB₁ inhibits cerebral CK activity, as well as the involvement of the oxidative stress on this inhibition. Brain CK activity was lower on days 14 and 21 post-feeding in animals that received AFB₁-contaminated diet compared to the control group (basal diet), similarly to the brain sodium-potassium pump (Na⁺, K⁺-ATPase) activity. On the other hand, lipid peroxidation and protein carbonylation levels were higher on days 14 and 21 post-feeding in animals fed with AFB₁-contaminated feed compared to the control group, while the antioxidant capacity against peroxyl radicals and thiol content was lower. Based on these evidences, the data demonstrated that diet containing AFB₁ severely affects CK activity, an essential enzyme that plays an important role in brain energy homeostasis. Also, the impairment of energetic homeostasis linked with the use and generation of ATP via inhibition of CK activity elicited an inhibition of enzymes ATP-dependent, such as Na⁺, K⁺-ATPase. Moreover, the inhibition of brain CK activity appears to be mediated by the oxidation of lipids, proteins, and thiol group, as well as by a reduction in the antioxidant capacity.

Impairment of the phosphotransfer network and performance in broiler chickens experimentally infected by Eimeria spp.: The role of the oxidative stress

The aim of this study was to evaluate whether infection Eimeria spp. in broiler chickens could negatively affect seric enzymes linked to adenosine triphosphate (ATP) metabolism and its relationship to oxidative stress. For this, 30 broiler chickens, 27 days-old, were divided into two groups (n = 15): the control group (C) and the group infected by Eimeria spp. (I). On days 1, 7 and 15 of the experiment, the animals were weighed, and fecal and blood samples were collected to evaluate the presence of oocysts and for serum biochemistry and enzymatic parameters, respectively. On day 15, one animal per repetition was submitted to euthanasia and intestinal fragments were collected for histopathological analyses. The body weight was lower in infected animals on day 15 of experiment, while oocyst counts were higher in infected animals on days 7 and 15 of the experiment. Serum levels of globulins were lower in infected animals on days 7 and 15 of experiment, while uric acid levels were higher in the same days, which represent changes on the immune system. Compared to the uninfected animals, on days 7 and 15, levels of serum globulins, triglycerides, creatine kinase and cholesterol were lower. Levels of adenylate kinase and reactive oxygen species (ROS) were higher on both days in infected animals, while levels of thiobarbituric acid-reactive substances (TBARS) were elevated on day 15. Lesions and immature forms of the parasite were observed in the intestines of infected birds. The phosphotransfer network elicited by an oxidative stress negatively affected the performance of broiler chickens with coccidiosis.

Tissue oxidative damage mediates impairment on phosphotransfer network during thymol intake: Effects on hepatic and renal bioenergetics

Recent evidences demonstrated that ingestion of several monoterpenes cause hepatic and renal damage due to impairment on mitochondrial energy production, eliciting a collapse on adenosine triphosphate (ATP) synthesis and consequently impairment on bioenergetic homeostasis. Thus, the aim of this study was to evaluate whether phosphotransfer network, catalyzed by creatine kinase (CK), adenylate kinase (AK), and pyruvate kinase (PK), can be a pathway to explain hepatic and renal bioenergetics homeostasis impairment due to thymol ingestion. Daily intake of thymol (40 mg/kg) significantly cause a decreased kidney weight and relative kidney weight compared to control group. The same dose of thymol inhibited renal cytosolic and mitochondrial CK activity as well as renal PK activity compared to control group. Finally, thymol (40 mg/kg) elicited a significant increase on renal reactive oxygen species and lipid damage levels, as well as an inhibition on antioxidant capacity against peroxyl radicals and non-protein thiol levels, which did not occur liver. Doses of 10 and 20 mg/kg of thymol administered orally for 30 consecutive days non-changed these variables. Based on these evidence, the data supported that intake of a high dose of thymol severely inhibits cytosolic and mitochondrial CK activity, a crucial enzyme to maintain cellular energy homeostasis. Moreover, high dietary thymol intake impaired communication between CK isoenzymes, which inhibits the attempts to regenerate ATP or to facilitate the CK/PCr shuttle to improve the intracellular ATP utilization and consumption. Moreover, the inhibition of renal CK and PK activities appears to be mediated by the renal oxidation of lipids and thiol groups, as well as by the reduction of the renal antioxidant capacity.

Antimicrobial activity of Terminalia catappa brown leaf extracts against Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853

The aim of this study was to determine the effects of various concentration of Terminalia catappa brown leaves extract which can inhibit the growth of Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853. The crushed-brown leaves of Terminalia catappa was extracted using 95% ethanol, filtered, and evaporated. The dried T. catappa extract was used to identify phytochemical content qualitatively. Total phenolic and flavonoid contents were also measured quantitatively from dried extract. The dried extracts were also dissolved in sterile aquadest and serial dilutions were prepared to final concentration of 30, 60 and 90%. A disc diffusion method was used to evaluate the antibacterial activity of various concentrations of ethanol extract of brown leaves of T. catappa. Inhibition zone diameter was measured to determine antibacterial activity. Gentamycin sulfate and distilled water were used as positive and negative controls, respectively. Dried ethanolic extract of brown T. catappa leaves contained flavonoid, quinon, phenolic, triterpenoid, and tannin. A total of 208.722 mg gallic acid equivalent/g extract of total phenolic and 35.7671 mg quercetin equivalent/g extract of total flavonoid were also found in the dried extract. The inhibition zone diameters of ethanolic extracts ranged from 1.73 to 9.06 mm ( S. aureus) and from 1.83 to 6.5 mm ( P. aeruginosa). The higher concentration of extract, the wider the inhibition zone diameters for both bacteria. P. aeruginosa was more resistant to high concentrations of extract (90%) than S. aureus. Ethanolic extracts of the brown leaves of T. catappa had different antibacterial effects against S. aureus and P. aeruginosa. The higher the concentration of extract, the wider the inhibition zone diameter for both bacteria. P. aeruginosa was more resistant to high concentrations of ethanolic extracts of the brown leaves of T. catappa.

Listeria monocytogenes impairs enzymes of the phosphotransfer network and alters antioxidant/oxidant status in cattle brain structures

Several evidences have suggested the involvement of enzymes belonging to the phosphotransfer network, formed by creatine kinase (CK), pyruvate kinase (PK) and adenylate kinase (AK), as well the oxidative stress on the pathogenesis of infectious diseases associated with the central nervous system (CNS). Thus, the aim of this study was to evaluate whether listeriosis alters the brain energy metabolism and/or causes oxidative stress in different brain structures of cattle experimentally infected by Listeria monocytogenes. The cytosolic CK activity was inhibited in the cerebral cortex, cerebellum, brainstem and hippocampus of infected animals compared to uninfected animals, while the mitochondrial CK activity was increased. The PK activity was inhibited in all brain structures of infected animals, while the AK activity was unchanged. Na⁺, K⁺-ATPase activity decreased in the cerebral cortex, cerebellum and hippocampus of animals infected by L. monocytogenes. Regarding the oxidative strees variables, the cerebellum and brainstem of infected animals showed increased thiobarbituric acid reactive substances, while the catalase activity was inhibited. Glutathione S-transferarase was inhibited in the cerebral cortex and brainstem of infected animals, and it was increased in the cerebellum. L. monocytogenes was quantified in the liver (n = 5/5) and cerebral cortex (n = 4/5) of the infected cattle. Based on these evidences, the nucleocytoplasmic communication between CK isoenzymes was insufficient to avoid an impairment of cerebral bioenergetics. Moreover, the inhibition on brain PK activity caused an impairment in the communication between sites of ATP generation and ATP utilization. The lipid peroxidation and alteration on antioxidant status observed in some brain structures were also involved during the disease. In summary, these alterations contribute to disease pathogenesis linked to CNS during cattle listeriosis.

Thiamethoxam induced hepatic energy changes in silver catfish via impairment of the phosphoryl transfer network pathway: Toxicological effects on energetics homeostasis

Precise coupling of spatially separated intracellular adenosine triphosphate (ATP)-producing and ATP-consuming processes exerts a pivotal role in bioenergetic homeostasis of living organisms, and the phosphotransfer network pathway, catalyzed by adenylate kinase (AK) and pyruvate kinase (PK), is fundamental in cellular and tissue energetic homeostasis. Measurement of the phosphotransfer network can provide new information for understanding the alterations in hepatic energetic metabolism during exposition to insecticides, such as thiamethoxam. Therefore, the aim of this study was to evaluate whether exposition to thiamethoxam negatively affects the hepatic enzymes of the phosphotransfer network in silver catfish (Rhamdia quelen). Hepatic AK and PK activities were inhibited at 3.75 μg L^-1 after 24 h of exposure and at 1.125 and 3.75 μg L^-1 after 96 h of exposure compared with the control group. The hepatic ATP levels were decreased following 3.75 μg L^-1 thiamethoxam treatment after 24 h of exposure and at 1.125 and 3.75 μg L^-1 after 96 h of exposure compared with the control group. The enzymatic activity of the phosphotransfer network and ATP levels did not recover after 48 h of recovery in clean water. Thus, the inhibition of hepatic AK and PK activities by thiamethoxam caused impairment of energy homeostasis in liver tissue, decreasing hepatic ATP availability. Moreover, the absence of a mutual compensatory mechanism between these enzymes directly contributes to ATP depletion and to a severe energetic dysregulation, which may contribute to toxic effects caused by thiamethoxam.

Aeromonas caviae inhibits hepatic enzymes of the phosphotransfer network in experimentally infected silver catfish: Impairment on bioenergetics

Several studies have been demonstrated that phosphotransfer network, through the adenylate kinase (AK) and pyruvate kinase (PK) activities, allows for new perspectives leading to understanding of disease conditions associated with disturbances in energy metabolism, metabolic monitoring and signalling. In this sense, the aim of this study was to evaluate whether experimental infection by Aeromonas caviae alters hepatic AK and PK activities of silver catfish Rhamdia quelen. Hepatic AK and PK activities decreased in infected animals compared to uninfected animals, as well as the hepatic adenosine triphosphate (ATP) levels. Also, a severe hepatic damage was observed in the infected animals due to the presence of dilation and congestion of vessels, degeneration of hepatocytes and loss of liver parenchyma architecture and sinusoidal structure. Therefore, we have demonstrated, for the first time, that experimental infection by A. caviae inhibits key enzymes linked to the communication between sites of ATP generation and ATP utilization. Moreover, the absence of a reciprocal compensatory mechanism between these enzymes contributes directly to hepatic damage and for a severe energetic imbalance, which may contribute to disease pathophysiology.

Citrobacter freundii impairs the phosphoryl transfer network in the gills of Rhamdia quelen: Impairment of bioenergetics homeostasis

The precise coupling of spatially separated intracellular adenosine triphosphate (ATP)-producing and ATP-consuming, catalyzed by creatine kinase (CK), adenylate kinase (AK), and pyruvate kinase (PK), is a critical process in the bioenergetics of tissues with high energy demand, such as the branchial tissue. The effects of Citrobacter freundii infection on gills remain poorly understood, limited only to histopathological studies. Thus, the aim of this study was to evaluate whether experimental infection by C. freundii impairs the enzymes of the phosphoryl transfer network in gills of silver catfish (Rhamdia quelen). The CK (cytosolic and mitochondrial) and AK activities decreased in infected compared to uninfected animals, while the PK activity did not differ between groups. The gill histopathology of infected animals revealed extensive degeneration with fusion and necrosis of secondary lamellae, detachment of superficial epithelium, aneurysm, vessel congestion and inflammatory process. Based on these evidences, the inhibition and absence of an efficient communication between CK compartments caused the impairment of the branchial bioenergetics homeostasis, which was not compensated by the augmentation on branchial AK activity in an attempt to restore energy homeostasis. In summary, these alterations contribute to disease pathogenesis linked to branchial tissue in animals infected with C. freundii.

Ichthyophthirius multifiliis impairs splenic enzymes of the phosphoryl transfer network in naturally infected Rhamdia quelen: effects on energetic homeostasis

Its integrated energetic and metabolic signaling roles place the phosphoryl transfer network, through the enzymes creatine kinase (CK), adenylate kinase (AK), and pyruvate kinase (PK), as a regulatory system coordinating components of the cellular bioenergetics network. Analysis of these enzymes provides new information and perspectives with which to understand disturbances in energetic metabolism between sites of adenosine triphosphate (ATP) generation and utilization. Thus, the aim of this study was to evaluate the involvement of the phosphoryl transfer network in splenic tissue linked with the pathogenesis of silver catfish naturally infected with Ichthyophthirius multifiliis. Splenic cytosolic and mitochondrial CK activities decreased in infected animals compared to uninfected animals, as was also observed for splenic PK activity and splenic ATP levels. In contrast, splenic AK activity increased in infected animals compared to uninfected animals. Based on this evidence, the inhibition and absence of efficient communication between CK isoenzymes cause the impairment of splenic bioenergetics, which is in turn compensated by the augmentation of splenic AK activity in an attempt to restore energy homeostasis. The inhibition of splenic PK activity impairs communication between sites of ATP generation and ATP utilization, as corroborated by splenic ATP depletion. In summary, these alterations contribute to disease pathogenesis linked to spleen tissue in animals infected with white spot disease.

Streptococcus agalactiae impairs cerebral bioenergetics in experimentally infected silver catfish

It is becoming evident that bacterial infectious diseases affect brain energy metabolism, where alterations of enzymatic complexes of the mitochondrial respiratory chain and creatine kinase (CK) lead to an impairment of cerebral bioenergetics which contribute to disease pathogenesis in the central nervous system (CNS). Based on this evidence, the aim of this study was to evaluate whether alterations in the activity of complex IV of the respiratory chain and CK contribute to impairment of cerebral bioenergetics during Streptococcus agalactiae infection in silver catfish (Rhamdia quelen). The activity of complex IV of the respiratory chain in brain increased, while the CK activity decreased in infected animals compared to uninfected animals. Brain histopathology revealed inflammatory demyelination, gliosis of the brain and intercellular edema in infected animals. Based on this evidence, S. agalactiae infection causes an impairment in cerebral bioenergetics through the augmentation of complex IV activity, which may be considered an adaptive response to maintain proper functioning of the electron respiratory chain, as well as to ensure ongoing electron flow through the electron transport chain. Moreover, inhibition of cerebral CK activity contributes to lower availability of ATP, contributing to impairment of cerebral energy homeostasis. In summary, these alterations contribute to disease pathogenesis linked to the CNS.

Aeromonas caviae alters the cytosolic and mitochondrial creatine kinase activities in experimentally infected silver catfish: Impairment on renal bioenergetics

Cytosolic and mitochondrial creatine kinases (CK), through the creatine kinase-phosphocreatine (CK/PCr) system, provide a temporal and spatial energy buffer to maintain cellular energy homeostasis. However, the effects of bacterial infections on the kidney remain poorly understood and are limited only to histopathological analyses. Thus, the aim of this study was to investigate the involvement of cytosolic and mitochondrial CK activities in renal energetic homeostasis in silver catfish experimentally infected with Aeromonas caviae. Cytosolic CK activity decreased in infected animals, while mitochondrial CK activity increased compared to uninfected animals. Moreover, the activity of the sodium-potassium pump (Na⁺, K⁺-ATPase) decreased in infected animals compared to uninfected animals. Based on this evidence, it can be concluded that the inhibition of cytosolic CK activity by A. caviae causes an impairment on renal energy homeostasis through the depletion of adenosine triphosphate (ATP) levels. This contributes to the inhibition of Na⁺, K⁺-ATPase activity, although the mitochondrial CK activity acted in an attempt to restore the cytosolic ATP levels through a feedback mechanism. In summary, A. caviae infection causes a severe energetic imbalance in infected silver catfish, which may contribute to disease pathogenesis.

Inhibition of the mitochondrial respiratory chain in gills of Rhamdia quelen experimentally infected by Pseudomonas aeruginosa: Interplay with reactive oxygen species

It has long been recognized that there are several infectious diseases linked to the impairment of enzymatic complexes of the mitochondrial respiratory chain, with consequent production of reactive oxygen species (ROS), that contribute to disease pathogenesis. In this study, we determined whether the inhibition on mitochondrial respiratory chain might be considered a pathway involved in the production of ROS in gills of Rhamdia quelen experimentally infected by P. aeruginosa. The animals were divided into two groups with six fish each: uninfected (the negative control group) and infected (the positive control group). On day 7 post-infection (PI), animals were euthanized and the gills were collected to assess the activities of complexes I-III, II and IV of the respiratory chain, as well as ROS levels. The activities of complexes I-III, II and IV of the respiratory chain in gills decreased, while the ROS levels increased in infected compared to uninfected animals. Moreover, a significant negative correlation was found between enzymatic activity of the complexes I-III and IV related to ROS levels in P. aeruginosa infected animals, corroborating to our hypothesis that inhibition on complexes of respiratory chain leads to ROS formation. Also, microscopic severe gill damage and destruction of primary and secondary lamellae were observed in infected animals, with the presence of hyperplasia, leukocytic infiltration and telangiectasia. In summary, we have demonstrated, for the first time, that experimental infection by P. aeruginosa inhibits the activities of mitochondrial complexes of respiratory chain and, consequently, impairs the cellular energy homeostasis. Moreover, the inhibition on mitochondrial complexes I-III and IV are linked to the ROS production, contributing to disease pathogenesis.