Tag Archives: fdps

Recently studies have demonstrated that alterations

Recently, studies have demonstrated that alterations on these enzymes contribute directly to disease pathophysiology during many infectious diseases, such as those caused by Trypanosoma evansi (Baldissera et al., 2015a,b) and Fasciola hepatica (Baldissera et al., 2015a,b). However, the activities of these enzymes during P. aeruginosa infection were not evaluated so far. Thus, due to the importance of fdps metabolism to the gills, the aim of this study was to evaluate whether experimental infection by P. aeruginosa strain PA01 alters AK, PK and CK activities in gills of silver catfish, Rhamdia quelen.

Materials and methods

Results

Discussion
The present study is novel since it evaluates important alterations in the phosphoryltransfer network in gills of animals experimentally infected by P. aeruginosa strain PA01. Our findings clearly shows the inhibition of the AK, PK and the cytosolic and mitochondrial CK, indicating an imbalance of energy homeostasis in gills of infected animals.
The systemic integration of energetic and metabolic signaling networks ensure cellular energy homeostasis and an adequate response to stress conditions, such as those caused by infectious diseases (Saks et al., 2006). Thus, the measurement of phosphoryltransfer network provides new perspectives for understanding the alterations in energy metabolism due to diseases. According to Dzeja et al. (2000), the coupling of spatially separated intracellular ATP-producing and ATP-consuming is a fundamental process to the proper energetic metabolism physiology. Therefore, an enzymatic network is necessary, catalyzed by AK, CK, and in special by PK, because they support high-energy phosphoryltransfer between ATP-generating and ATP-consuming process (Dzeja and Terzic, 1998). We observed that AK, PK and cytosolic and mitochondrial CK activities were inhibited by P. aeruginosa infection, which may result in decreased availability of ATP and impairment of energy supply. These enzymes are intimately related in such a way, that a decrease in one enzyme may lead to an increase of the other, a mechanism known as energy compensation. This mechanism contributes to efficient intracellular energetic communication, maintaining the balance between cellular ATP consumption and production in attempt to preserve the energetic homeostasis (Alekssev et al., 2012). On the other hand, a concomitant decrease on these enzymes in the gills was observed in infected animals with P. aeruginosa strain PA01, contributing directly to the impairment of synthesis and release of ATP on the gills, which may be related to disease pathophysiology. Recently, a study conducted by Baldissera et al. (2015a,b) demonstrated that inhibition on hepatic, cardiac and cerebral AK, PK and CK activities contributes directly to disease pathophysiology during T. evansi infection.
Recently, studies have demonstrated that impairment on enzymes of energy metabolism is linked to the appearance of clinical signs and disease evolution, such as observed during other infectious diseases (Baldissera et al., 2015a,b). Impairment on AK activity has been associated to disturbances on cellular functions, loss of osmoprotection activity, as well as focal hemorrhage, one of the main clinical symptom caused by P. aeruginosa (Toren et al., 1994). Also, inhibition of CK activity may lead to an important dysfunction in fish respiration, since mitochondrial CK activity is a modulator of the metabolic potential localized in mitochondria connected to the respiratory chain (Brdicza et al., 1994).
In summary, we have demonstrated, for the first time, that experimental infection by P. aeruginosa inhibits key enzymes linked to the production and utilization of metabolic energy in silver catfish, and consequently, impairs the cellular energy homeostasis, contributing to disease pathogenesis.

Introduction
Since the identification of the porcine reproductive and respiratory syndrome virus (PRRSV) in 1991 as the causative agent of PRRS in Europe, several studies have demonstrated the remarkable phenotypic and genetic diversity between strains and within subtypes (Wensvoort et al., 1991; Meulenberg et al., 1993; Han et al., 2013a, 2013b, 2013c; Morgan et al., 2013; Stadejek et al., 2013; Weesendorp et al., 2014; Amarilla et al., 2015; Salguero et al., 2015). PRRSV has been recently included within the new genus Rodartevirus which comprises the species suid 1 rodartevirus and suid 2 rodartervirus, corresponding to the viruses named PRRSV-1 and PRRSV-2, respectively (Kuhn et al., 2016).

br Figure thinsp xA Representative sequential chest radiographs and the

Figure 2. Representative sequential chest radiographs and the graphs of excursion and peak motion of the diaphragms obtained by chest dynamic radiography (“dynamic X-ray phrenicography”). (a) Radiograph of the resting end-expiratory position. (b) Radiograph of the resting end-inspiratory position. (c) Graph showing the vertical excursions and the peak motion speeds of the bilateral diaphragm. A board-certified radiologist placed a point of interest (red point) on the highest point of each fdps on the radiograph at the resting end-expiratory position (a). These points were automatically traced by the template-matching technique throughout the respiratory phase (double arrows in b) (Supplementary Video S1); red double arrow indicates the vertical excursion of the right diaphragm and blue double arrow indicates that of the left diaphragm. Based on locations of the points on sequential radiographs, the vertical excursions and the peak motion speeds of the bilateral diaphragm were calculated (c). The lowest point (0 mm) of the excursion on the graph indicated that the highest point of each diaphragm was at the resting end-expiratory position (ie, null point was set at the end-expiratory phase) (c). (Color version of figure is available online.)Figure optionsDownload full-size imageDownload high-quality image (305 K)Download as PowerPoint slide

Pulmonary Function Tests

The pulmonary function tests were performed in all participants on the same day of the imaging study. Parameters of pulmonary function tests were measured according to the American Thoracic Society guidelines 20 ;  21 using a pulmonary function instrument with computer processing (DISCOM-21 FX, Chest MI Co, Tokyo, Japan).

Statistical Analysis

Descriptive statistics are expressed as mean ± standard deviation for continuous variables and as frequency and percentages for nominal variables. A paired t test was used to compare the excursion and peak motion speed between the right diaphragm and the left diaphragm. The associations between the excursions of the diaphragms and participants\’ characteristics were evaluated by means of the Pearson\’s correlation coefficient and a simple linear regression or Student\’s t test depending on the type of variable (ie, continuous or nominal variable). Continuous variables were height, weight, BMI, tidal volume, vital capacity (VC, %VC), forced expiratory volume (FEV1, FEV1%, and %FEV1), and nominal variables were gender and smoking history. The robustness of the results of the univariate analyses was assessed with multiple linear regression models. The significance level for all tests was 5% (two sided). All data were analyzed using a commercially available software program (JMP; version 12, SAS, Cary, NC, USA).

Results

Participants\’ Characteristics

Table 1 shows the clinical characteristics of all the participants (n = 172).

Excursions and Peak Motion Speeds of the Bilateral Diaphragm

Univariate Analysis of Associations Between the Diaphragmatic Excursions and Participants\’ Demographics

Figure 3. Estimated regression line of the excursion of the diaphragm on BMI or tidal volume. (a) Association between BMI and excursion of the right diaphragm. (b) Association between BMI and excursion of the left diaphragm. (c) Association between tidal volume and excursion of the right diaphragm. (d) Association between tidal volume and excursion of the left diaphragm. Lines show estimated regression (a–d). All scatterplots show correlations (P < 0.05). BMI, body mass index.Figure optionsDownload full-size imageDownload high-quality image (226 K)Download as PowerPoint slide

Multivariate Analysis of Associations Between the Excursions and Participants\’ Demographics

Multiple linear regression analysis using all variables as factors (Model 1) demonstrated that weight, BMI, and tidal volume were independently associated with the bilateral excursion of the diaphragms (all P < 0.05) after adjusting for other clinical variables, including age, gender, smoking history, height, VC, %VC, FEV1, FEV1%, and %FEV1. There were no significant associations between the excursion of the diaphragms and variables including age, gender, smoking history, height, VC, %VC, FEV1, FEV1%, and %FEV1 (Table 4). Additionally, a multiple linear regression model using age, gender, BMI, tidal volume, VC, FEV1, and smoking history as factors (Model 2) was also fit as a sensitivity analysis, taking into account the correlation among variables (eg, BMI, height, and weight; VC and %VC; FEV1, FEV1%, and %FEV1). Model 2 (Supplementary Data S1) gave results consistent with Model 1 (Table 4): higher BMI and higher tidal volume were independently associated with the increased bilateral excursion of the diaphragms (all P < 0.05). The adjusted R2 in Model 1 was numerically higher than that in Model 2 (right, 0.19 vs. 0.16, respectively; left, 0.16 vs. 0.13, respectively).