Pseudomonas syringae: Enterprising epiphyte and stealthy parasite

© 2019 The Authors. Pseudomonas syringae is best known as a plant pathogenic bacterium that causes diseases in a multitude of hosts, and it has been used as a model organism to understand the biology of plant disease. Pathogenic and non-pathogenic isolates of P. syringae are also commonly found living as epiphytes and in the wider environment, including water sources such as rivers and precipitation. Ice-nucleating strains of P. syringae are associated with frost damage to crops. The genomes of numerous strains of P. syringae have been sequenced and molecular genetic studies have elucidated many aspects of this pathogen’s interaction with its host plants

Engaging teenagers with genetics and genomics through a school-based competition: Pilot evaluation

As part of a university outreach programme, the authors ran an interschool competition encouraging youngpeople (year 10, age 14–15) to explore their ideas about the likely social impacts of whole genome screening. Schoolsparticipating in the competition selected teams of 4–5 young people who participated in a one day workshop. Thisworkshop provided an introduction to whole genome screening, what it is and what it might (and might not) be able totell us about our future health. The workshop also included sessions on communicating scientific ideas through film (e.g.storyboarding and basic editing). Students were then instructed to create a 4–6 minute film about genomics and whatissues it might present for individuals and/or society. Students reconvened for a second workshop to view and discuss thefilms created. This paper focuses on a thematic analysis of the films entered in the competition, exploring the issues thatstudents raise. In addition to the thematic analysis, quantitative and qualitative data were collected that enable apreliminary exploration of student learning. This will be explored in the context of what students of this age already knowand how they have built upon this learning during the competition

Research on the Nature, Characteristics, and Causes of Accounting Errors: The Need For a Multi-method Approach

Knowledge of the occurrence and detection of errors in accounting populations is of great importance to auditors in assessing risks, evaluating the efficacy of statistical sampling methods, and planning effective and efficient audit procedures to address risks. A significant body of research exists that examines these issues. Prior studies have focused primarily on auditordetected errors. A basic assumption of these studies is that detected errors are an accurate reflection of all significant errors present. That is, there are not a substantial number of undetected errors, or that undetected errors share the same characteristics (e.g., error direction) as detected errors. However, little evidence exists regarding the accuracy of this assumption. Further, there has been little consideration of factors that may affect differences between detected and actual errors and the implications of these differences on research conclusions. This paper presents a model of the variables involved in the error generation and error detection processes. Variables that have been explored in prior research are discussed along with those requiring further investigation. Finally, the paper identifies confounding variables to be controlled in future studies and makes suggestions for improving extant error study methods

Multi-Failure Mode Risk Assessment of the Houston/Galveston Bridge System to Hurricane Threats

This research implements the first Houston/Galveston area hurricane risk assessment of bridges for multiple failure modes: bridge deck uplift and bridge scour. Due to recent hurricane damage of bridges, emergency managers need to understand the potential state of the bridge network immediately following a storm for effective mitigation and post-event planning. To that end, this study builds a new database of bridge information necessary for vulnerability modeling, adapts current deterministic models of bridge deck uplift and scour for a probabilistic framework and expands the scour models to include a qualitative estimate for embankment scour. The study area bridges are tested under various hurricane scenario events to reveal the likelihood of damage. Potential applications include retrofit prioritization, real-time spatial damage modeling and better informed preparation. By understanding the risk hurricanes pose to the bridge system, emergency officials can better plan rescue and recovery efforts before a storm impacts the Texas coast

An investigation into the effectiveness of trade unions in advancing the cause of workers during strikes in the face of an emerging culture of violence and criminality.

Masters Degree. University of KwaZulu-Natal, Pietermaritzburg.No abstract available

An Empirical Study of Dynamic Scheduling on Rings of Processors

The authors empirically analyze and compare two distributed low-overhead policies for scheduling dynamic tree-structured computations on rings of identical PEs. The experiments show that both policies give significant parallel speedup on large classes of computations, and that one yields almost optimal speedup on moderate size rings. They believe that the methodology of experiment design and analysis will prove useful in other such studies

Pseudomonas kirkiae sp. nov., a novel species isolated from oak in the United Kingdom, and phylogenetic considerations of the genera Pseudomonas, Azotobacter and Azomonas

As the current episode of Acute Oak Decline (AOD) continues to affect native British oak in the United Kingdom, ongoing isola-tions from symptomatic and healthy oak have yielded a large Pseudomonas species population. These strains could be divided into taxa representing three potential novel species. Recently, two of these taxa were described as novel Pseudomonas species in the Pseudomonas fluorescens lineage. Here, we demonstrate using a polyphasic approach that the third taxon represents another novel Pseudomonas species. The 16S rRNA gene sequencing assigned the strains to the Pseudomonas aeruginosa lineage, while multilocus sequence analysis (based on partial gyrB, rpoB and rpoD sequences) placed the 13 strains in a single cluster on the border of the Pseudomonas stutzeri group. Whole genome intra-species comparisons (based on average nucleotide identity and in silico DNA–DNA hybridization) confirmed that the strains belong to a single taxon, while the inter-species comparisons with closest phylogenetic relatives yielded similarity values below the accepted species threshold. Therefore, we propose these strains as a novel species, namely Pseudomonas kirkiae sp. nov., with the type strain FRB 229T (P4CT=LMG 31089T=NCPPB 4674T). The phylogenetic analyses performed in this study highlighted the difficulties in assigning novel species to the genus Pseudomonas due to its polyphyletic nature and close relationship to the genus Azotobacter. We further propose that a thorough taxonomic re-evaluation of the genus Pseudomonas is essential and should be performed in the near future

Incidence and public health burden of sunburn among beachgoers in the United States.

The beach environment creates many barriers to effective sun protection, putting beachgoers at risk for sunburn, a well-established risk factor for skin cancer. Our objective was to estimate incidence of sunburn among beachgoers and evaluate the relationship between sunburn incidence and sun-protective behaviors. A secondary analysis, of prospective cohorts at 12 locations within the U.S. from 2003 to 2009 (n = 75,614), were pooled to evaluate sunburn incidence 10-12 days after the beach visit. Behavioral and environmental conditions were cross-tabulated with sunburn incidence. Multivariable logistic regression was used to estimate the association between new sunburn and sun-protective behaviors. Overall, 13.1% of beachgoers reported sunburn. Those aged 13-18 years (16.5%), whites (16.0%), and those at beach locations along the Eastern Seaboard (16.1%), had the highest incidence of sunburn. For those spending ≥5 h in the sun, the use of multiple types of sun protection reduced odds of sunburn by 55% relative to those who used no sun protection (Odds Ratio = 0.45 (95% Confidence Interval:0.27-0.77)) after adjusting for skin type, age, and race. Acute health effects of sunburn tend to be mild and self-limiting, but potential long-term health consequences are more serious and costly. Efforts to encourage and support proper sun-protective behaviors, and increase access to shade, protective clothing, and sunscreen, can help prevent sunburn and reduce skin cancer risk among beachgoers

Chromosomal ampC mutations in cefpodoxime-resistant ESBL-negative uropathogenic escherichia coli

AmpC beta-lactamase is an enzyme commonly produced by Escherichia coli that causes resistance to cephalosporins and penicillins. Enzyme production is controlled by the strength of the promoter encoded by the chromosomal ampC gene, with the level of production affected by the presence of certain mutations in this region. This study sets out to determine the prevalence of ampC promoter mutations present in a group of uropathogenic E. coli strains. A total of 50 clinical strains of E. coli were collected from urine samples between June 2011 and November 2011. Strains were investigated for the presence of mutations in the chromosomal ampC promoter region by amplification and sequencing of a 271 bp product. The presence of ampC-carrying plasmids derived from other species was also determined, to exclude these from further analysis. ampC-carrying plasmids were found in 10 of the 50 strains, all of which were of the CIT-type. Analysis of the chromosomal ampC promoter region in the 40 remaining strains showed mutations at 16 different positions, with 18 different genotype patterns detected overall. The most common ampC chromosomal mutation, present in 25 of 40 strains, was a T→A transition at position -32. This mutation has been shown by others to increase enzyme production by up to 46-fold. Altogether, three separate mutations (-32, -42 and -13ins) were present in 90% of the 40 non-plasmid strains, indicating a strong association with the resistance observed. It appears, therefore, that the majority of AmpC-mediated resistance in E. coli can be accounted for by just three point mutations in the chromosome

Description of a novel species of Leclercia, Leclercia tamurae sp. nov. and proposal of a novel genus Silvania gen. nov. containing two novel species Silvania hatchlandensis sp. nov. and Silvania confinis sp. nov. isolated from the rhizosphere of oak

Background: Acute Oak Decline (AOD) is a decline disease first reported on native oaks in the UK, but in recentyears reports from further afield such as Europe and the Middle East, indicate that the distribution and host range isincreasing at an alarming rate. The stem weeping symptoms of the disease partially develop due to polymicrobialhostinteraction, caused by several members of the order Enterobacterales. While investigating the rhizosphere soil ofAOD-unaffected trees, termed ‘healthy’ trees, and diseased oaks suffering from Acute Oak Decline (AOD), an enrichmentmethod designed for enhanced recovery of Enterobacterales led to the recovery of several isolates that couldnot be classified as any existing species. These isolates showed a close relationship to the genus Leclercia, of whichboth species are of clinical importance, but the type species Leclercia adecarboxylata also displays plant growth-promotingproperties in the rhizosphere.Results: Partial sequencing of four housekeeping genes revealed similarity to the genus Leclercia with varyingdegrees of relatedness. As such a complete polyphasic approach was used to determine the true taxonomic positionof these isolates. This involved whole genome sequencing, phylogenomic analysis, phylogenetic analysis of both the16S rRNA and four housekeeping gene sequences, combined with phenotypic testing and fatty acid analysis. Boththe phylogenomic and phylogenetic analyses separated the isolates into four clusters, two of which were containedin the Leclercia clade. The remaining two clusters formed a separate lineage far removed from any currently definedspecies. Further investigation into the role of the isolates as plant growth-promoting bacteria as well as plant pathogenswas investigated computationally, revealing a number of plant growth-promoting traits as well as virulencegenes related to motility, adhesion and immune modulation.Conclusion: Based on the genotypic and phenotypic data presented here, these isolates could be differentiatedfrom each other and their closest neighbours. As such we propose the description of Leclercia tamurae sp. nov