Evaluation of pro- and anti-inflammatory interleukins in the mammary gland of goats experimentally infected with Staphylococcus chromogenes.

The aim of this work was to evaluate the relative gene expression levels of the cytokines IL- 1B, IL-8, IL-12, IFN-γ, IL-4, IL-10 and TGF-ß in somatic milk cells of French Alpine breed, anestrous goats that were experimentally infected in the left mammary gland with Staphylococcus chromogenes during the lactation peak. Milk samples were obtained from both glands for 21 consecutive days post infection. Total RNA was extracted, and real-time PCR was conducted using primers specific to each cytokine. The relative RNA expression of the evaluated cytokines was determined by the comparative method 2-ΔΔCT, using milk from the right gland of the goats as a reference (control) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as an endogenous control. According to the Wilcoxon test results, IL-1B and IL-12 expression levels showed significant differences compared to those in the control group (p⟨0.05) from 24 hours post infection until the end of lactation; on day three, IL1ß, IL8, IL12 and TGF-ß had a statistically significant change in expression with respect to those in the control group (p⟨0.05); closer to the end of the lactation period, there is no overexpression of the anti-inflammatory interleukins (IL-4 and TGF-ß) which may reflect the effort of the host immune system to eradicate the microorganism from the mammary gland.

Root growth restraint can be an acclimatory response to low pH and is associated with reduced cell mortality: a possible role of class III peroxidases and NADPH oxidases.

Low pH (<5.0) can significantly decrease root growth but whether this is a direct effect of H(+) or an active plant response is examined here. Tomato (Solanum lycopersicum cv Micro-Tom) roots were exposed directly or gradually to low pH through step-wise changes in pH over periods ranging from 4 to 24 h. Roots exposed gradually to pH 4.5 grew even less than those exposed directly, indicating a plant-coordinated response. Direct exposure to pH 4.0 suppressed root growth and caused high cell mortality, in contrast to roots exposed gradually, in which growth remained inhibited but cell viability was maintained. Total class III peroxidase activity increased significantly in all low pH treatments, but was not correlated with the observed differential responses. Use of the enzyme inhibitors salicylhydroxamic acid (SHAM) or diphenyleneiodonium chloride (DPI) suggest that peroxidase and, to a lesser extent, NADPH oxidase were required to prevent or reduce injury in all low pH treatments. However, a role for other enzymes, such as the alternative oxidase is also possible. The results with SHAM, but not DPI, were confirmed in tobacco BY-2 cells. Our results indicate that root growth inhibition from low pH can be part of an active plant response, and suggest that peroxidases may have a critical early role in reducing loss of cell viability and in the observed root growth constraint.