Genomic heterogeneity of Dichelobacter nodosus within and between UK sheep flocks and between age groups within a flock

BackgroundFootrot and interdigital dermatitis are endemic infectious diseases in all sheep farming regions, impairing welfare and production. The development of efficacious vaccines against the primary causative pathogen has been hampered by the extensive antigenic diversity of Dichelobacter nodosus. Understanding the heterogeneity of the pathogen within and between flocks is essential if the feasibility of bespoke vaccine production is to be assessed for use in the U.K.ResultsIn this study 56 ewe and lamb isolates from 9 flocks were compared by D. nodosus serogroup and Multi Locus Sequence Type which provides significantly enhanced discriminatory power for molecular epidemiology. Serogroup heterogeneity between flocks ranged from two to five unique serogroups per flock. Three flocks contained isolates of two serogroups, two flocks contained isolates of three serogroups and one flock included isolates of five serogroups. Analysis of 25 isolates from one flock with high prevalence of lameness, identified that serogroup and sequence type was significantly correlated with age. Significantly higher proportion of lambs were infected with serogroup B (principally ST85) as opposed to serogroup H (principally ST86), which predominated amongst adult sheep.ConclusionsGenomic heterogeneity of the pathogen was significantly lower within flock compared to heterogenicity observed between flocks. Furthermore, this study indicates that within a flock, the host-pathogen dynamics and susceptibility to particular D. nodosus strains may be age dependent

Novel inflammatory cell infiltration scoring system to investigate healthy and footrot affected ovine interdigital skin

Ovine footrot is a degenerative disease of sheep feet leading to the separation of hoofhorn from the underlying skin and lameness. This study quantitatively examined histological features of the ovine interdigital skin as well as their relationship with pro-inflammatory cytokine (IL-1_) and virulent Dichelobacter nodosus in footrot. From 55 healthy and 30 footrot ovine feet, parallel biopsies (one fixed for histology) were collected post-slaughter and analysed for lesions and histopathological analysis using haematoxylin and eosin and Periodic Acid-Schiff. Histological lesions were similar in both conditions while inflammatory scores mirror IL-1_ expression levels. Increased inflammatory score corresponded with high virulent D. nodosus load and was significant (

Deletion of methylglyoxal synthase gene (mgsA) increased sugar co-metabolism in ethanol-producing Escherichia coli

The use of lignocellulose as a source of sugars for bioproducts requires the development of biocatalysts that maximize product yields by fermenting mixtures of hexose and pentose sugars to completion. In this study, we implicate mgsA encoding methylglyoxal synthase (and methylglyoxal) in the modulation of sugar metabolism. Deletion of this gene (strain LY168) resulted in the co-metabolism of glucose and xylose, and accelerated the metabolism of a 5-sugar mixture (mannose, glucose, arabinose, xylose and galactose) to ethanol

Early severe inflammatory responses to uropathogenic E. coli predispose to chronic and recurrent urinary tract infection

Chronic infections are an increasing problem due to the aging population and the increase in antibiotic resistant organisms. Therefore, understanding the host-pathogen interactions that result in chronic infection is of great importance. Here, we investigate the molecular basis of chronic bacterial cystitis. We establish that introduction of uropathogenic E. coli (UPEC) into the bladders of C3H mice results in two distinct disease outcomes: resolution of acute infection or development of chronic cystitis lasting months. The incidence of chronic cystitis is both host strain and infectious dose-dependent. Further, development of chronic cystitis is preceded by biomarkers of local and systemic acute inflammation at 24 hours post-infection, including severe pyuria and bladder inflammation with mucosal injury, and a distinct serum cytokine signature consisting of elevated IL-5, IL-6, G-CSF, and the IL-8 analog KC. Mice deficient in TLR4 signaling or lymphocytes lack these innate responses and are resistant, to varying degrees, to developing chronic cystitis. Treatment of C3H mice with the glucocorticoid anti-inflammatory drug dexamethasone prior to UPEC infection also suppresses the development of chronic cystitis. Finally, individuals with a history of chronic cystitis, lasting at least 14 days, are significantly more susceptible to redeveloping severe, chronic cystitis upon bacterial challenge. Thus, we have discovered that the development of chronic cystitis in C3H mice by UPEC is facilitated by severe acute inflammatory responses early in infection, which subsequently are predisposing to recurrent cystitis, an insidious problem in women. Overall, these results have significant implications for our understanding of how early host-pathogen interactions at the mucosal surface determines the fate of disease

Effective, Broad Spectrum Control of Virulent Bacterial Infections Using Cationic DNA Liposome Complexes Combined with Bacterial Antigens

Protection against virulent pathogens that cause acute, fatal disease is often hampered by development of microbial resistance to traditional chemotherapeutics. Further, most successful pathogens possess an array of immune evasion strategies to avoid detection and elimination by the host. Development of novel, immunomodulatory prophylaxes that target the host immune system, rather than the invading microbe, could serve as effective alternatives to traditional chemotherapies. Here we describe the development and mechanism of a novel pan-anti-bacterial prophylaxis. Using cationic liposome non-coding DNA complexes (CLDC) mixed with crude F. tularensis membrane protein fractions (MPF), we demonstrate control of virulent F. tularensis infection in vitro and in vivo. CLDC+MPF inhibited bacterial replication in primary human and murine macrophages in vitro. Control of infection in macrophages was mediated by both reactive nitrogen species (RNS) and reactive oxygen species (ROS) in mouse cells, and ROS in human cells. Importantly, mice treated with CLDC+MPF 3 days prior to challenge survived lethal intranasal infection with virulent F. tularensis. Similarly to in vitro observations, in vivo protection was dependent on the presence of RNS and ROS. Lastly, CLDC+MPF was also effective at controlling infections with Yersinia pestis, Burkholderia pseudomallei and Brucella abortus. Thus, CLDC+MPF represents a novel prophylaxis to protect against multiple, highly virulent pathogens

Supporting Today’s and Tomorrow’s Learners: Innovative Ideas for Student Development

The increasing emphasis on self-directed learning in the health professions, in order to produce effective lifelong learners means that today’s veterinary students can no longer rely solely on the study skills developed at secondary school, such as rote memorisation of facts or basic concepts. Students are required to apply knowledge, and analyse and synthesise information, in order to solve complex clinical problems. The increasing recognition of the importance of facilitating ‘deep’ learning is mirrored in the ‘new’ curricula established in recent years at a number of veterinary schools, including those in London and Nottingham. These changes have important implications for the way that learners are supported throughout their professional training. Anecdotally, it has been observed that a number of students struggle by the time they reach the third year of the veterinary course, which has a greater clinical focus, when they realise that tried and tested methods of learning and revision – such as re-writing lecture notes – no longer work for them. It is at this point that many students – especially those with specific learning difficulties such as dyslexia – approach learning support officers and tutors for help and advice. It can be difficult at this stage to encourage students to relinquish their study habits in favour of alternative strategies that promote active learning. International students can also present issues regarding support. The purpose of this workshop will be to encourage participants to think about the learning needs of their own students, to reflect on the nature and scope of learning support currently being provided and to consider some alternative strategies for supporting successful, self-directed learning from the outset of their professional training

Supporting Today’s and Tomorrow’s Learners: Innovative Ideas for Student Development

The increasing emphasis on self-directed learning in the health professions, in order to produce effective lifelong learners means that today’s veterinary students can no longer rely solely on the study skills developed at secondary school, such as rote memorisation of facts or basic concepts. Students are required to apply knowledge, and analyse and synthesise information, in order to solve complex clinical problems. The increasing recognition of the importance of facilitating ‘deep’ learning is mirrored in the ‘new’ curricula established in recent years at a number of veterinary schools, including those in London and Nottingham. These changes have important implications for the way that learners are supported throughout their professional training. Anecdotally, it has been observed that a number of students struggle by the time they reach the third year of the veterinary course, which has a greater clinical focus, when they realise that tried and tested methods of learning and revision – such as re-writing lecture notes – no longer work for them. It is at this point that many students – especially those with specific learning difficulties such as dyslexia – approach learning support officers and tutors for help and advice. It can be difficult at this stage to encourage students to relinquish their study habits in favour of alternative strategies that promote active learning. International students can also present issues regarding support. The purpose of this workshop will be to encourage participants to think about the learning needs of their own students, to reflect on the nature and scope of learning support currently being provided and to consider some alternative strategies for supporting successful, self-directed learning from the outset of their professional training

Effective numerical approximations by intervals

SIGLETIB: in RN 6361 (1985,4) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

YscP, a Yersinia protein required for Yop secretion that is surface exposed, and released in low Ca2+

The Yersinia Ysc apparatus is made of more than 20 proteins, 11 of which have homologues in many type III systems. Here, we characterize YscP from Yersinia enterocolitica. This 515-residue protein has a high proline content, a large tandem repetition and a slow migration in SDS-PAGE. Unlike the products of neighbouring genes, it has a counterpart only in Pseudomonas aeruginosa and it varies even between Yersinia Ysc machineries. An yscPDelta97-465 mutant was unable to secrete any Yop, even under conditions overcoming feedback inhibition of Yop synthesis. Interestingly, a cloned yscPDelta57-324 from Yersinia pestis introduced in the yscPDelta97-465 mutant can sustain a significant Yop secretion and thus partially complemented the mutation. This explains the leaky phenotype observed with the yscP mutant of Y. pestis. In accordance with this secretion deficiency, YscP is required for the delivery of Yop effectors into macrophages. Mechanical shearing, immunolabelling and electron microscopy experiments showed that YscP is exposed at the bacterial surface when bacteria are incubated at 37 degrees C in the presence of Ca2+ and thus do not secrete Yops. At 37 degrees C, when Ca2+ ions are chelated, YscP is released like a Yop protein. We conclude that YscP is a part of the Ysc injectisome which is localized at the bacterial surface and is destabilized by Ca2+ chelation