Conservation and Diversity of Seed Associated Endophytes in Zea across Boundaries of Evolution, Ethnography and Ecology

Endophytes are non-pathogenic microbes living inside plants. We asked whether endophytic species were conserved in the agriculturally important plant genus Zea as it became domesticated from its wild ancestors (teosinte) to modern maize (corn) and moved from Mexico to Canada. Kernels from populations of four different teosintes and 10 different maize varieties were screened for endophytic bacteria by culturing, cloning and DNA fingerprinting using terminal restriction fragment length polymorphism (TRFLP) of 16S rDNA. Principle component analysis of TRFLP data showed that seed endophyte community composition varied in relation to plant host phylogeny. However, there was a core microbiota of endophytes that was conserved in Zea seeds across boundaries of evolution, ethnography and ecology. The majority of seed endophytes in the wild ancestor persist today in domesticated maize, though ancient selection against the hard fruitcase surrounding seeds may have altered the abundance of endophytes. Four TRFLP signals including two predicted to represent Clostridium and Paenibacillus species were conserved across all Zea genotypes, while culturing showed that Enterobacter, Methylobacteria, Pantoea and Pseudomonas species were widespread, with γ-proteobacteria being the prevalent class. Twenty-six different genera were cultured, and these were evaluated for their ability to stimulate plant growth, grow on nitrogen-free media, solubilize phosphate, sequester iron, secrete RNAse, antagonize pathogens, catabolize the precursor of ethylene, produce auxin and acetoin/butanediol. Of these traits, phosphate solubilization and production of acetoin/butanediol were the most commonly observed. An isolate from the giant Mexican landrace Mixteco, with 100% identity to Burkholderia phytofirmans, significantly promoted shoot potato biomass. GFP tagging and maize stem injection confirmed that several seed endophytes could spread systemically through the plant. One seed isolate, Enterobacter asburiae, was able to exit the root and colonize the rhizosphere. Conservation and diversity in Zea-microbe relationships are discussed in the context of ecology, crop domestication, selection and migration

K-ras mutations in sinonasal cancers in relation to wood dust exposure

<p>Abstract</p> <p>Background</p> <p>Cancer in the sinonasal tract is rare, but persons who have been occupationally exposed to wood dust have a substantially increased risk. It has been estimated that approximately 3.6 million workers are exposed to inhalable wood dust in EU. In previous small studies of this cancer, <it>ras </it>mutations were suggested to be related to wood dust exposure, but these studies were too limited to detect statistically significant associations.</p> <p>Methods</p> <p>We examined 174 cases of sinonasal cancer diagnosed in Denmark in the period from 1991 to 2001. To ensure uniformity, all histological diagnoses were carefully reviewed pathologically before inclusion. Paraffin embedded tumour samples from 58 adenocarcinomas, 109 squamous cell carcinomas and 7 other carcinomas were analysed for K-<it>ras </it>codon 12, 13 and 61 point mutations by restriction fragment length polymorphisms and direct sequencing. Information on occupational exposure to wood dust and to potential confounders was obtained from telephone interviews and from registry data.</p> <p>Results</p> <p>Among the patients in this study, exposure to wood dust was associated with a 21-fold increased risk of having an adenocarcinoma than a squamous cell carcinoma compared to unexposed [OR = 21.0, CI = 8.0–55.0]. K-<it>ras </it>was mutated in 13% of the adenocarcinomas (seven patients) and in 1% of squamous cell carcinomas (one patient). Of these eight mutations, five mutations were located in the codon 12. The exact sequence change of remaining three could not be identified unambiguously. Among the five identified mutations, the G→A transition was the most common, and it was present in tumour tissue from two wood dust exposed adenocarcinoma patients and one patient with unknown exposure. Previously published studies of sinonasal cancer also identify the GGT → GAT transition as the most common and often related to wood dust exposure.</p> <p>Conclusion</p> <p>Patients exposed to wood dust seemed more likely to develop adenocarcinoma compared to squamous cell carcinomas. K-<it>ras </it>mutations were detected in 13% of adenocarcinomas. In this study and previously published studies of sinonasal cancer the found K-<it>ras </it>mutations, were almost exclusively G → A transitions. In conclusion, our study, based on a large representative collection of human SNC tumours, indicates that K-<it>ras </it>mutations are relatively infrequent, and most commonly occur in adenocarcinomas. Wood dust exposure alone was not found to be explanatory for the G→A mutations, but combination of exposure to tobacco, wood dust, and possibly other occupational agents may be a more likely explanation. Overall, the study suggests a limited role for K-<it>ras </it>mutations in development of sinonasal cancer.</p

Enteropathy-associated T cell lymphoma subtypes are characterized by loss of function of SETD2

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Chapter 11: Emerging approaches in the analysis of inks on questioned documents

Questioned document is one of the oldest fields of examination reported in forensic science. Documents are used as physical (nowadays sometimes virtual) traces of human transactions, thus questioning, falsification and counterfeiting certainly have existed since their invention and routine use. This is also the case for biblical texts and art pieces for which authenticity and authorship are often disputed. While mainly handwriting comparison was reported in early works, the composition and characteristics of inks on paper were often briefly discussed (see for example the early works of Demelle or Raveneau in the XVIIe century ). Since then, many technological developments have impacted questioned document examination, both with regard to the ink and paper production, as well as to the writing instruments or printing techniques. Nowadays, further progress have changed the world of (questioned) documents, through the introduction of virtual documents using electronic signatures and security documents such as passports using mixed physical and digital biometric data. Thus, the document examiner' expertise has to quickly evolve and adapt to such developments, sometimes necessitating the combination of skills from different disciplines not always co-existing in forensic laboratories (such as chemistry, physics, statistics, engineering, material science, computer science). After a brief overview of the historical development in both ink formulation and analysis, this chapter will investigate the relevance of rapidly evolving technologies for application to the examination of questioned documents in a forensic perspective