Transcriptional changes in Teladorsagia circumcincta upon encountering host tissue of differing immune status.

The aim of this study was to elucidate transcriptional changes in the parasitic nematode Teladorsagia circumcincta upon encountering either naïve or immune ovine hosts. Pools of 100 000 exsheathed 3rd- stage T. circumcincta larvae were exposed in vitro to either an immune or naïve ovine abomasal environment, RNA was extracted from the larvae and sequenced using the Roche 454 platform. Each sample produced approximately 82 000 reads that assembled to give approximately 5500 Isotigs (contigs). The two sequence datasets were clustered together to give a total of 6969 clusters of which 18 were differentially expressed (P<0·001) between the two groups. Clusters with a predominance of reads in larvae exposed to the immune abomasal environment encoded homologues of peptidyl-glycine alpha-amidating monooxygenase, heat shock-protein 16-2 and IDA-1, a tyrosine phosphatase-like receptor protein. Clusters with a predominance of reads in the naïve environment encoded homologues of cytochrome b, EGg Laying defective family member 21 and NADH dehydrogenase subunit 5. Gene ontology analyses indicated that larvae exposed to the immune environment showed an increase in expression of genes involved in 'carbon utilization', 'response to stimulus' and 'developmental process'. These data suggest that T. circumcincta modulates gene expression in response to the immune status of the host.

Genome sequence of the Chlamydophila abortus variant strain LLG.

Chlamydophila abortus is a common cause of ruminant abortion. Here we report the genome sequence of strain LLG, which differs genotypically and phenotypically from the wild-type strain S26/3. Genome sequencing revealed differences between LLG and S26/3 to occur in pseudogene content, in transmembrane head/inc family proteins, and in biotin biosynthesis genes.

Multilocus sequence typing of a global collection of Pasteurella multocida isolates from cattle and other host species demonstrates niche association.

BACKGROUND: Pasteurella multocida causes disease in many host species throughout the world. In bovids, it contributes to bovine respiratory disease (BRD) and causes haemorrhagic septicaemia (HS). Previous studies have suggested that BRD-associated P. multocida isolates are of limited diversity. A multilocus sequence typing (MLST) scheme for P. multocida was used to determine whether the low levels of diversity reported are due to the limited discriminatory power of the typing method used, restricted sample selection or true niche association. Bovine respiratory isolates of P. multocida (n = 133) from the UK, the USA and France, collected between 1984 and 2008 from both healthy and clinically affected animals, were typed using MLST. Isolates of P. multocida from cases of HS, isolates from other host species and data from the MLST database were used as comparison. RESULTS: Bovine respiratory isolates were found to be clonal (I(S)(A) 0.45) with 105/128 belonging to clonal complex 13 (CC13). HS isolates were not related to bovine respiratory isolates. Of the host species studied, the majority had their own unique sequence types (STs), with few STs being shared across host species, although there was some cross over between porcine and bovine respiratory isolates. Avian, ovine and porcine isolates showed greater levels of diversity compared to cattle respiratory isolates, despite more limited geographic origins. CONCLUSIONS: The homogeneity of STs of bovine respiratory P. multocida observed, and the differences between these and P. multocida subpopulations from bovine non-respiratory isolates and non-bovine hosts may indicate niche association.

Teladorsagia circumcincta: the transcriptomic response of a multi-drug-resistant isolate to ivermectin exposure in vitro.

The emergence and spread of anthelmintic resistance in parasitic nematodes is a serious threat to the sustainability of the livestock industry. Resistance has a genetic component but the underlying mechanisms and the means by which resistant parasites survive anthelmintic treatment are still poorly understood. Differential gene expression may be implicated, especially in multi-drug resistant parasites. In this study, we investigated the transcriptomic response of a triple drug-resistant isolate of Teladorsagia circumcincta to ivermectin exposure in vitro, using Roche 454 sequencing. The study generated ∼100,000 new EST sequences, ∼50,000 each from the ivermectin-exposed and -unexposed pools of parasites. Bioinformatic analysis of the expression profiles revealed statistically significant differences in the mean expression levels of four KEGG orthologous groups, namely 'translation', 'amino acid metabolism', 'carbohydrate metabolism' and 'xenobiotic degradation and metabolism'. Notably, candidate resistance genes such as p-glycoproteins and cytochrome P450s were poorly represented in both datasets. Clusters of sequences, containing both exposed and unexposed ESTs, also revealed statistically significant differences. Four clusters were identified as cytochrome c oxidase subunits, two of these clusters had a statistically significant increase in the number of exposed ESTs compared to unexposed ESTs. Four clusters were identified as vitellogenin; three of these clusters had a statistically significant decrease in number of exposed ESTs compared to unexposed ESTs.

Genome Sequence of Lawsonia intracellularis Strain N343, Isolated from a Sow with Hemorrhagic Proliferative Enteropathy.

Lawsonia intracellularis is the etiological agent of proliferative enteropathy (PE), causing mild or acute hemorrhagic diarrhea in infected animals. Here we report the genome sequence of strain N343, isolated from a sow that died of hemorrhagic PE. N343 contains 24 single nucleotide polymorphisms and 90 indels compared to the reference strain PHE/MN1-00.

Genetic variability of Chlamydophila abortus strains assessed by PCR-RFLP analysis of polymorphic membrane protein-encoding genes.

This study used PCR-RFLP to investigate the genetic variability of pmp-encoding genes from fifty-two Chlamydophila abortus (C. abortus) strains originating from abortion cases from various geographical regions and host species. Six primer pairs were used to PCR-amplify DNA fragments encoding eighteen pmps. PCR products were digested using four restriction endonucleases and Bayesian methodologies were used to compare RFLP profiles and assign strains to a RFLP genotype. Strains could be assigned to 2 genotypes in the region encoding pmp18D, 3 genotypes in the regions encoding pmp1A-pmp2B, pmp3E-pmp6H and pmp11G-pmp15G, 4 genotypes in the region encoding pmp7G-pmp10G and 5 genotypes in the region encoding pmp16G-pmp17G. In all regions, the majority of strains (88.4-96.1%) had the same genotype as the reference strain S26/3. No correlation could be made between genotype, host species or geographical origin except for the two variant Greek strains, LLG and POS, which formed a discrete genotype in all pmp-encoding regions except pmp18D. Relative rates of evolution calculated for each pmp-encoding gene locus suggest that differing selective pressures and functional constraints may exist on C. abortus polymorphic membrane proteins. These findings suggest that although intraspecies heterogeneity of pmp-encoding genes in C. abortus is low, the sequence heterogeneity should be an important consideration when using pmps as the basis for novel diagnostics or vaccine development.