The host metabolite D-serine contributes to bacterial niche specificity through gene selection

Escherichia coli comprise a diverse array of both commensals and niche-specific pathotypes. The ability to cause disease results from both carriage of specific virulence factors and regulatory control of these via environmental stimuli. Moreover, host metabolites further refine the response of bacteria to their environment and can dramatically affect the outcome of the host–pathogen interaction. Here, we demonstrate that the host metabolite, D-serine, selectively affects gene expression in E. coli O157:H7. Transcriptomic profiling showed exposure to D-serine results in activation of the SOS response and suppresses expression of the Type 3 Secretion System (T3SS) used to attach to host cells. We also show that concurrent carriage of both the D-serine tolerance locus (dsdCXA) and the locus of enterocyte effacement pathogenicity island encoding a T3SS is extremely rare, a genotype that we attribute to an ‘evolutionary incompatibility’ between the two loci. This study demonstrates the importance of co-operation between both core and pathogenic genetic elements in defining niche specificity

Lung adenocarcinoma presenting as a solitary gingival metastasis: a case report

<p>Abstract</p> <p>Introduction</p> <p>Gingival metastases are very rare and generally occur in disseminated tumors. We report a case of solitary gingival metastasis of lung cancer.</p> <p>Case presentation</p> <p>We report the case of a 74-year-old asymptomatic Caucasian woman affected by a rapidly growing, painless gingival swelling. Histopathologic examination of the excisional biopsy showed metastasis of poorly differentiated thyroid transcription factor 1-positive adenocarcinoma. A total-body computed tomographic scan revealed a tumor of the right lung lower lobe with ipsilateral, mediastinal lymph node swelling. Moreover, bone scintigraphy revealed no bone metastases. No other metastases were found, so we planned a multi-modal therapeutic approach with a curative intent. However, the tumor proved to be intrinsically resistant and highly aggressive.</p> <p>Conclusion</p> <p>The presentation of solitary gingival metastasis is exceptional. In view of its rapid clinical evolution, our case confirms that gingival metastasis is an important prognostic factor. This behavior raises the question whether the poor prognosis for patients with tumors with oral metastases depends on its diffuse spread or on its highly malignant nature.</p

Plexiform neurofibroma of the submandibular gland in patient with von Recklinghausen's disease

Plexiform neurofibroma of the submandibular gland is an extremely rare tumor. Herein, we report a case of plexiform neurofibroma in a patient with a von Recklinghausen's disease (NF-1) who presented with a submandibular mass mimicking a submandibular gland tumor. Complete surgical excision provides the best treatment and final diagnosis. A neurofibroma should be considered in the differential diagnosis for submandibular mass

Ensuring competency in end-of-life care: controlling symptoms

BACKGROUND: Palliative medicine is assuming an increasingly important role in patient care. The Education for Physicians in End-of-life Care (EPEC) Project is an ambitious program to increase core palliative care skills for all physicians. It is not intended to transmit specialty level competencies in palliative care. METHOD: The EPEC Curriculum was developed to be a comprehensive syllabus including trainer notes, multiple approaches to teaching the material, slides, and videos of clinical encounters to trigger discussion are provided. The content was developed through a combination of expert opinion, participant feedback and selected literature review. Content development was guided by the goal of teaching core competencies not included in the training of generalist and non-palliative medicine specialist physicians. RESULTS: Whole patient assessment forms the basis for good symptom control. Approaches to the medical management of pain, depression, anxiety, breathlessness (dyspnea), nausea/vomiting, constipation, fatigue/weakness and the symptoms common during the last hours of life are described. CONCLUSION: While some physicians will have specialist palliative care services upon which to call, most in the world will need to provide the initial approaches to symptom control at the end-of-life

Detection of segregation distortion loci in triticale (x Triticosecale Wittmack) based on a high-density DArT marker consensus genetic linkage map

<p>Abstract</p> <p>Background</p> <p>Triticale is adapted to a wide range of abiotic stress conditions, is an important high-quality feed stock and produces similar grain yield but more biomass compared to other crops. Modern genomic approaches aimed at enhancing breeding progress in cereals require high-quality genetic linkage maps. Consensus maps are genetic maps that are created by a joint analysis of the data from several segregating populations and different approaches are available for their construction. The phenomenon that alleles at a locus deviate from the Mendelian expectation has been defined as segregation distortion. The study of segregation distortion is of particular interest in doubled haploid (DH) populations due to the selection pressure exerted on the plants during the process of their establishment.</p> <p>Results</p> <p>The final consensus map, constructed out of six segregating populations derived from nine parental lines, incorporated 2555 DArT markers mapped to 2602 loci (1929 unique). The map spanned 2309.9 cM with an average number of 123.9 loci per chromosome and an average marker density of one unique locus every 1.2 cM. The R genome showed the highest marker coverage followed by the B genome and the A genome. In general, locus order was well maintained between the consensus linkage map and the component maps. However, we observed several groups of loci for which the colinearity was slightly uneven. Among the 2602 loci mapped on the consensus map, 886 showed distorted segregation in at least one of the individual mapping populations. In several DH populations derived by androgenesis, we found chromosomes (2B, 3B, 1R, 2R, 4R and 7R) containing regions where markers exhibited a distorted segregation pattern. In addition, we observed evidence for segregation distortion between pairs of loci caused either by a predominance of parental or recombinant genotypes.</p> <p>Conclusions</p> <p>We have constructed a reliable, high-density DArT marker consensus genetic linkage map as a basis for genomic approaches in triticale research and breeding, for example for multiple-line cross QTL mapping experiments. The results of our study exemplify the tremendous impact of different DH production techniques on allele frequencies and segregation distortion covering whole chromosomes.</p

Phylogeny and Biogeography of the Carnivorous Plant Family Sarraceniaceae

The carnivorous plant family Sarraceniaceae comprises three genera of wetland-inhabiting pitcher plants: Darlingtonia in the northwestern United States, Sarracenia in eastern North America, and Heliamphora in northern South America. Hypotheses concerning the biogeographic history leading to this unusual disjunct distribution are controversial, in part because genus- and species-level phylogenies have not been clearly resolved. Here, we present a robust, species-rich phylogeny of Sarraceniaceae based on seven mitochondrial, nuclear, and plastid loci, which we use to illuminate this family's phylogenetic and biogeographic history. The family and genera are monophyletic: Darlingtonia is sister to a clade consisting of Heliamphora+Sarracenia. Within Sarracenia, two clades were strongly supported: one consisting of S. purpurea, its subspecies, and S. rosea; the other consisting of nine species endemic to the southeastern United States. Divergence time estimates revealed that stem group Sarraceniaceae likely originated in South America 44–53 million years ago (Mya) (highest posterior density [HPD] estimate = 47 Mya). By 25–44 (HPD = 35) Mya, crown-group Sarraceniaceae appears to have been widespread across North and South America, and Darlingtonia (western North America) had diverged from Heliamphora+Sarracenia (eastern North America+South America). This disjunction and apparent range contraction is consistent with late Eocene cooling and aridification, which may have severed the continuity of Sarraceniaceae across much of North America. Sarracenia and Heliamphora subsequently diverged in the late Oligocene, 14–32 (HPD = 23) Mya, perhaps when direct overland continuity between North and South America became reduced. Initial diversification of South American Heliamphora began at least 8 Mya, but diversification of Sarracenia was more recent (2–7, HPD = 4 Mya); the bulk of southeastern United States Sarracenia originated co-incident with Pleistocene glaciation, <3 Mya. Overall, these results suggest climatic change at different temporal and spatial scales in part shaped the distribution and diversity of this carnivorous plant clade

Why do General Practitioners Decline Training to Improve Management of Medically Unexplained Symptoms?

BACKGROUND: General practitioners’ (GPs) communication with patients presenting medically unexplained symptoms (MUS) has the potential to somatize patients’ problems and intensify dependence on medical care. Several reports indicate that GPs have negative attitudes about patients with MUS. If these attitudes deter participation in training or other methods to improve communication, practitioners who most need help will not receive it. OBJECTIVE: To identify how GPs’ attitudes to patients with MUS might inhibit their participation with training to improve management. DESIGN: Qualitative study. PARTICIPANTS: GPs (N = 33) who had declined or accepted training in reattribution techniques in the context of a research trial. APPROACH: GPs were interviewed and their accounts analysed qualitatively. RESULTS: Although attitudes that devalued patients with MUS were common in practitioners who had declined training, these coexisted, in the same practitioners, with evidence of intuitive and elaborate psychological work with these patients. However, these practitioners devalued their psychological skills. GPs who had accepted training also described working psychologically with MUS but devalued neither patients with MUS nor their own psychological skills. CONCLUSIONS: GPs’ attitudes that suggested disengagement from patients with MUS belied their pursuit of psychological objectives. We therefore suggest that, whereas negative attitudes to patients have previously been regarded as the main barrier to involvement in measures to improve patient management, GPs devaluing of their own psychological skills with these patients may be more important

Complexity absorption : A processual strategic approach to corporate entrepreneurship strategy

The author Haina Zhang acknowledges the support of research grant received from the Lancaster University Research Committee (award reference: SGS21/33). The author is also grateful to Professor David Brown for his suggestions on earlier version of this paper.Peer reviewedPublisher PD