A Rapid LAMP-Based Method for Screening Poultry Samples for Campylobacter Without Enrichment.

Campylobacter is the most prominent bacterium associated with foodborne disease and the majority of human infection cases are attributed to chicken. Rapid methods capable of determining the Campylobacter status of poultry products in a short time are needed in today's fast-paced food supply chain. In this study, we developed and evaluated an easy to perform, rapid and robust method for direct detection of Campylobacter in poultry carcasses based on loop-mediated isothermal DNA AMPlification (LAMP). The method does not require bacterial culture or DNA purification and generates results in just an hour. A total of 171 swabs from chicken and turkey slaughter houses were analyzed in parallel by both LAMP and conventional culture-based enumeration methods to evaluate the performance of the rapid method. Campylobacter was detected by LAMP in 100% of swabs with an enumeration result of ≥800 cfu/swab, and 98.6% (69 out of 70) of samples reported as negative by enumeration (≤10 cfu/swab) were also negative by LAMP. The method is also suitable for analysis of boot swabs from poultry houses, and therefore it represents a convenient screening tool that can be implemented on farm, at slaughter houses, processing plants or retail, to help with the control of Campylobacter contamination throughout the food supply chain. The inclusion of an internal amplification control prevents any potential false negative results due to DNA amplification inhibitors that might be present in the sample.

Identification of novel peptides for horse meat speciation in highly processed foodstuffs.

There is a need for robust analytical methods to support enforcement of food labelling legislation. Proteomics is emerging as a complementary methodology to existing tools such as DNA and antibody-based techniques. Here we describe the development of a proteomics strategy for the determination of meat species in highly processed foods. A database of specific peptides for nine relevant animal species was used to enable semi-targeted species determination. This principle was tested for horse meat speciation, and a range of horse-specific peptides were identified as heat stable marker peptides for the detection of low levels of horse meat in mixtures with other species.

Scribble is required for normal epithelial cell-cell contacts and lumen morphogenesis in the mammalian lung.

During lung development, proper epithelial cell arrangements are critical for the formation of an arborized network of tubes. Each tube requires a lumen, the diameter of which must be tightly regulated to enable optimal lung function. Lung branching and lumen morphogenesis require close epithelial cell-cell contacts that are maintained as a result of adherens junctions, tight junctions and by intact apical-basal (A/B) polarity. However, the molecular mechanisms that maintain epithelial cohesion and lumen diameter in the mammalian lung are unknown. Here we show that Scribble, a protein implicated in planar cell polarity (PCP) signalling, is necessary for normal lung morphogenesis. Lungs of the Scrib mouse mutant Circletail (Crc) are abnormally shaped with fewer airways, and these airways often lack a visible, 'open' lumen. Mechanistically we show that Scrib genetically interacts with the core PCP gene Vangl2 in the developing lung and that the distribution of PCP pathway proteins and Rho mediated cytoskeletal modification is perturbed in Scrib(Crc/Crc) lungs. However A/B polarity, which is disrupted in Drosophila Scrib mutants, is largely unaffected. Notably, we find that Scrib mediates functions not attributed to other PCP proteins in the lung. Specifically, Scrib localises to both adherens and tight junctions of lung epithelia and knockdown of Scrib in lung explants and organotypic cultures leads to reduced cohesion of lung epithelial cells. Live imaging of Scrib knockdown lungs shows that Scrib does not affect bud bifurcation, as previously shown for the PCP protein Celsr1, but is required to maintain epithelial cohesion. To understand the mechanism leading to reduced cell-cell association, we show that Scrib associates with ß-catenin in embryonic lung and the sub-cellular distribution of adherens and tight junction proteins is perturbed in mutant lung epithelia. Our data reveal that Scrib is required for normal lung epithelial organisation and lumen morphogenesis by maintaining cell-cell contacts. Thus we reveal novel and important roles for Scrib in lung development operating via the PCP pathway, and in regulating junctional complexes and cell cohesion.

Identification of a Z-band associated protein complex involving KY, FLNC and IGFN1.

The KY protein underlies a form of muscular dystrophy in the mouse but its role in muscle remains elusive. Immunodetection of endogenous KY protein in C2C12-derived myotubes and expression of a recombinant form in neonatal cardiomyocytes indicated that KY is a Z-band associated protein. Moreover, characterization of a KY interacting protein fragment led to the identification of Igfn1 (Immunoglobulin-like and fibronectin type 3 domain containing 1). Igfn1 is a transcriptionally complex locus encoding many protein variants. A yeast two-hybrid screen identified the Z-band protein filamin C (FLNC) as an interacting partner. Consistent with this, expression of an IGFN1 recombinant fragment showed that the three N-terminal globular domains, common to at least five IGFN1 variants, are sufficient to provide Z-band targeting. Taken together, the yeast two-hybrid, biochemical and immunofluorescence data support the notion that KY, IGFN1 and FLNC are part of a Z-band associated protein complex likely to provide structural support to the skeletal muscle sarcomere.

The after-hours mutant reveals a role for Fbxl3 in determining mammalian circadian period.

By screening N-ethyl-N-nitrosourea-mutagenized animals for alterations in rhythms of wheel-running activity, we identified a mouse mutation, after hours (Afh). The mutation, a Cys(358)Ser substitution in Fbxl3, an F-box protein with leucine-rich repeats, results in long free-running rhythms of about 27 hours in homozygotes. Circadian transcriptional and translational oscillations are attenuated in Afh mice. The Afh allele significantly affected Per2 expression and delayed the rate of Cry protein degradation in Per2::Luciferase tissue slices. Our in vivo and in vitro studies reveal a central role for Fbxl3 in mammalian circadian timekeeping.

A mutation in the F-box gene, Fbxo11, causes otitis media in the Jeff mouse.

Otitis media (OM), inflammation of the middle ear, is the most common cause of hearing impairment and surgery in children. Recurrent and chronic forms of OM are known to have a strong genetic component, but nothing is known of the underlying genes involved in the human population. We have previously identified a novel semi-dominant mouse mutant, Jeff, in which the heterozygotes develop chronic suppurative OM (Hardisty, R.E., Erven, A., Logan, K., Morse, S., Guionaud, S., Sancho-Oliver, S., Hunter, A.J., Brown, S.D. and Steel, K.P. (2003) The deaf mouse mutant Jeff (Jf) is a single gene model of otitis media. J. Assoc. Res. Otolaryngol., 4, 130-138.) and represent a model for chronic forms of OM in humans. We demonstrate here that Jeff carries a mutation in an F-box gene, Fbxo11. Fbxo11 is expressed in epithelial cells of the middle ears from late embryonic stages through to day 13 of postnatal life. In contrast to Jeff heterozygotes, Jeff homozygotes show cleft palate, facial clefting and perinatal lethality. We have also isolated and characterized an additional hypomorphic mutant allele, Mutt. Mutt heterozygotes do not develop OM but Mutt homozygotes also show facial clefting and cleft palate abnormalities. FBXO11 is one of the first molecules to be identified, contributing to the genetic aetiology of OM. In addition, the recessive effects of mutant alleles of Fbxo11 identify the gene as an important candidate for cleft palate studies in the human population.

Pharmacodynamic response and inhibition of growth of human tumor xenografts by the novel histone deacetylase inhibitor PXD101.

Histone acetylation has a central role in the control of gene expression, influencing transcriptional control of many genes, including tumor suppressor genes. PXD101 is a novel hydroxamate-type inhibitor of histone deacetylase activity that inhibits histone deacetylase activity in HeLa cell extracts with an IC(50) of 27 nM and induces a concentration-dependent (0.2-5 micro M) increase in acetylation of histone H4 in tumor cell lines. PXD101 is cytotoxic in vitro in a number of tumor cell lines with IC(50)s in the range 0.2-3.4 micro M as determined by a clonogenic assay and induces apoptosis. Treatment of nude mice bearing human ovarian and colon tumor xenografts with PXD101 (10-40 mg/kg/day i.p.) daily for 7 days causes a significant dose-dependent growth delay with no obvious signs of toxicity to the mice. Growth delay is also observed for xenografts of cisplatin-resistant ovarian tumor cells. A marked increase in acetylation of H4 is detected in blood and tumor of mice 3 h after treatment with PXD101. The inhibition of growth of human tumor xenografts in mice, with no apparent toxicity, suggests that PXD101 has potential as a novel antitumor agent. Furthermore, the ability to measure histone acetylation in blood samples could provide a suitable pharmacodynamic end point to monitor drug activity.

Suprabasal alpha6beta4 integrin expression in epidermis results in enhanced tumourigenesis and disruption of TGFbeta signalling.

Inappropriate alpha6beta4 integrin expression correlates with a high risk of tumour progression in stratified squamous epithelia. Targeted expression of alpha6beta4 in the suprabasal layers of transgenic mouse epidermis dramatically increased the frequency of papillomas, carcinomas and metastases induced by chemical carcinogenesis, independent of the beta4 cytoplasmic domain. Suprabasal alpha6beta4 also perturbed transforming growth factor beta (TGFbeta) signalling as demonstrated by decreased nuclear Smad2 in transgenic epidermis and tumours. In cultured keratinocytes, suprabasal alpha6beta4 relieved TGFbeta-mediated growth inhibition and blocked nuclear translocation of activated Smad2/3. Responsiveness to TGFbeta could be restored by inhibiting cadherin-mediated cell-cell adhesion or phosphoinositide 3-kinase (PI3-K) activity, but not by inhibiting mitogen-activated protein kinase (MAPK) activity. These data suggest that suprabasal alpha6beta4 promotes tumourigenesis by preventing TGFbeta from suppressing clonal expansion of initiated cells in the epidermal basal layer.