Correlating blood immune parameters and a CCT7 genetic variant with the shedding of Salmonella enterica serovar Typhimurium in swine
VETERINARY MICROBIOLOGY
Authors: Uthe, J. J.; Wang, Y.; Qu, L.; Nettleton, D.; Tuggle, C. K.; Bearson, S. M. D.
Abstract
The porcine response to Salmonella infection is critical for control of Salmonella fecal shedding and the establishment of Salmonella carrier status. In this study, 40 crossbred pigs were intranasally inoculated with Salmonella enterica serovar Typhimurium (Salmonella Typhimurium) and monitored for Salmonella fecal shedding and blood immune parameters at 2, 7, 14 and 20 days post-inoculation (dpi). Using a multivariate permutation test, a positive correlation was observed between Salmonella Typhimurium shedding levels at 2 and 7 dpi and serum interferon-gamma (IFN-gamma) levels at 2 dpi (p < 0.05), with Salmonella being shed in greater numbers from animals with higher IFN gamma levels. A positive correlation was also observed between IFN gamma levels and the number of banded neutrophils (2 dpi), circulating neutrophils (7 and 14 dpi), monocytes (7 dpi), and white blood cells (WBCs) (7, 14 and 20 dpi). We have further performed association studies on these immune response parameters as well as shedding status of the Salmonella-infected pigs with a single nucleotide polymorphism (SNP) in the porcine gene CCT7, previously shown by our group to be transcriptionally up-regulated in swine experimentally inoculated with Salmonella Typhimurium. Our analyses with the 40 pigs suggest a positive association (p=0.0012) of SNP genotype A/G at position AK240296.c1153G > A of the CCT7 gene with Salmonella shedding at 7 dpi compared to the G/G homozygote genotype. Linking specific genes and genetic polymorphisms with the porcine immune response to Salmonella infection and shedding may identify potential markers for carrier pigs as well as targets for disease diagnosis, intervention and prevention. (C) 2008 Elsevier B.V. All rights reserved.
An ensemble of cryo-EM structures of TRiC reveal its conformational landscape and subunit specificity
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Authors: Jin, Mingliang; Han, Wenyu; Liu, Caixuan; Zang, Yunxiang; Li, Jiawei; Wang, Fangfang; Wang, Yanxing; Cong, Yao
Abstract
TRiC/CCT assists the folding of similar to 10% of cytosolic proteins through an ATP-driven conformational cycle and is essential in maintaining protein homeostasis. Here, we determined an ensemble of cryoelectron microscopy (cryo-EM) structures of yeast TRiC at various nucleotide concentrations, with 4 open-state maps resolved at near-atomic resolutions, and a closed-state map at atomic resolution, revealing an extra layer of an unforeseen N-terminal allosteric network. We found that, during TRiC ring closure, the CCT7 subunit moves first, responding to nucleotide binding; CCT4 is the last to bind ATP, serving as an ATP sensor; and CCT8 remains ADP-bound and is hardly involved in the ATPase-cycle in our experimental conditions; overall, yeast TRiC consumes nucleotide in a 2-ring positively coordinated manner. Our results depict a thorough picture of the TRiC conformational landscape and its allosteric transitions from the open to closed states in more structural detail and offer insights into TRiC subunit specificity in ATP consumption and ring closure, and potentially in substrate processing.