Serologic Surveillance of Selected Viral and Bacterial Pathogens in South Carolina’s Feral Swine Population

Feral swine (Sus scrofa) are considered an invasive species that is comprised of the wild descendants of domestic swine, European wild boar, and hybrids of these two species. Feral swine were historically associated with the major river drainages in Coastal South Carolina. However, natural range expansion and human release and relocation of feral swine appear to be sources of their expansion into areas not previously occupied. Although an exact estimate of feral swine population numbers is not available, in 2006 feral swine were reported in 42 of 46 South Carolina counties, compared to 46 of 46 counties reporting feral swine activity in 2011. Feral swine can serve as reservoirs for a number of diseases including pseudorabies, swine brucellosis (Brucella spp.), porcine respiratory and reproductive syndrome and porcine circovirus which may be passed to livestock and, in some cases, native wildlife and humans. The National Wildlife Disease Program within the US Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services conducted serologic surveys for pseudorabies virus, brucellosis, porcine circovirus, and porcine respiratory and reproductive syndrome virus in South Carolina feral pig populations from 2007- 2012. During that period, we opportunistically sampled and collected serum from 545 feral pigs. Overall, 111 of 544 (20.40%) animals tested positive for antibodies to pseudorabies, 87 of 545 (15.96%) animals tested positive for antibodies to brucellosis, 171 of 306 (55.88%) animals tested positive for antibodies to porcine circovirus, and seven of 312 (2.24%) animals tested positive for antibodies to porcine respiratory and reproductive syndrome. Positive cases of pseudorabies and brucellosis were spatially limited to populations closely associated with the major river drainages in Coastal South Carolina. These positive cases of pseudorabies and brucellosis were found in areas of long established pig populations. The seven positive cases of porcine respiratory and reproductive syndrome were limited to one geographic cluster within the Congaree and Wateree river confluence and two clusters along the PeeDee River Drainage. These clusters of seropositive cases indicate a more geographically localized distribution of porcine respiratory and reproductive syndrome. Interestingly, positive cases of porcine circovirus appeared to be evenly distributed across all sample locations in South Carolina. A more spatially and temporally consistent sampling strategy is recommended to investigate linear spread of pathogens along river drainages and throughout the feral swine population in South Carolina

Gram Negative Bacteria Are Associated with the Early Stages of Necrotizing Enterocolitis

Introduction: Necrotizing enterocolitis (NEC) affects 5–10 % of infants born weighing less than 1500 g. Most models of NEC recapitulate late-stage disease with gut necrosis and elevated inflammatory mediators. Evaluation of NEC at earlier, less lethal stages of disease will allow investigation of initial disease triggers and may advance our understanding of temporal relationships between factors implicated in NEC pathogenesis. In this manuscript, we describe our investigation of early NEC and test the hypothesis that bacteria and inflammatory mediators differ between animals with early NEC and disease fre

Generation and Validation of a Shewanella oneidensis MR-1 Clone Set for Protein Expression and Phage Display

A comprehensive gene collection for S. oneidensis was constructed using the lambda recombinase (Gateway) cloning system. A total of 3584 individual ORFs (85%) have been successfully cloned into the entry plasmids. To validate the use of the clone set, three sets of ORFs were examined within three different destination vectors constructed in this study. Success rates for heterologous protein expression of S. oneidensis His- or His/GST- tagged proteins in E. coli were approximately 70%. The ArcA and NarP transcription factor proteins were tested in an in vitro binding assay to demonstrate that functional proteins can be successfully produced using the clone set. Further functional validation of the clone set was obtained from phage display experiments in which a phage encoding thioredoxin was successfully isolated from a pool of 80 different clones after three rounds of biopanning using immobilized anti-thioredoxin antibody as a target. This clone set complements existing genomic (e.g., whole-genome microarray) and other proteomic tools (e.g., mass spectrometry-based proteomic analysis), and facilitates a wide variety of integrated studies, including protein expression, purification, and functional analyses of proteins both in vivo and in vitro

Transcriptome Profiling of Shewanella oneidensis Gene Expression following Exposure to Acidic and Alkaline pH

The molecular response of Shewanella oneidensis MR-1 to variations in extracellular pH was investigated based on genomewide gene expression profiling. Microarray analysis revealed that cells elicited both general and specific transcriptome responses when challenged with environmental acid (pH 4) or base (pH 10) conditions over a 60-min period. Global responses included the differential expression of genes functionally linked to amino acid metabolism, transcriptional regulation and signal transduction, transport, cell membrane structure, and oxidative stress protection. Response to acid stress included the elevated expression of genes encoding glycogen biosynthetic enzymes, phosphate transporters, and the RNA polymerase sigma-38 factor (rpoS), whereas the molecular response to alkaline pH was characterized by upregulation of nhaA and nhaR, which are predicted to encode an Na(+)/H(+) antiporter and transcriptional activator, respectively, as well as sulfate transport and sulfur metabolism genes. Collectively, these results suggest that S. oneidensis modulates multiple transporters, cell envelope components, and pathways of amino acid consumption and central intermediary metabolism as part of its transcriptome response to changing external pH conditions

Recovery and Analysis of Formyltetrahydrofolate Synthetase Gene Sequences from Natural Populations of Acetogenic Bacteria

Primers for PCR amplification of partial (1,102 of 1,680 bp) formyltetrahydrofolate synthetase (FTHFS) gene sequences were developed and tested. Partial FTHFS sequences were successfully amplified from DNA from pure cultures of known acetogens, from other FTHFS-producing organisms, from the roots of the smooth cordgrass, Spartina alterniflora, and from fresh horse manure. The amplimers recovered were cloned, their nucleotide sequences were determined, and their translated amino acid sequences were used to construct phylogenetic trees. We found that FTHFS sequences from homoacetogens formed a monophyletic cluster that did not contain sequences from nonhomoacetogens and that FTHFS sequences appear to be informative regarding major physiological features of FTHFS-producing organisms