Use of a dual reporter plasmid to demonstrate bactofection with an attenuated aroa- derivative of Pasteurella multocida b:2

A reporter plasmid pSRG has been developed which expresses red fluorescent protein (RFP) from a constitutive prokaryotic promoter within Pasteurella multocida B:2 and green fluorescent protein (GFP) from a constitutive eukaryotic promoter within mammalian cells. This construct has been used to determine the location and viability of the bacteria when moving from the extracellular environment into the intracellular compartment of mammalian cells. Invasion assays with embryonic bovine lung (EBL) cells and an attenuated AroA- derivative of Pasteurella multocida B:2 (strain JRMT12), harbouring the plasmid pSRG, showed that RFP-expressing bacteria could be detected intracellularly at 3 h post-invasion. At this stage, some EBL cells harbouring RFP-expressing bacteria were observed to express GFP simultaneously, indicating release of the plasmid into the intracellular environment. At 5 h post-invasion, more EBL cells were expressing GFP, while still harbouring RFP-expressing bacteria. Concurrently, some EBL cells were shown to express only GFP, indicating loss of viable bacteria within these cells. These experiments proved the functionality of the pSRG dual reporter system and the potential of P. multocida B:2 JRMT12 for bactofection and delivery of a DNA vaccine

Combinatorial quorum sensing allows bacteria to resolve their social and physical environment

Quorum sensing (QS) is a cell–cell communication system that controls gene expression in many bacterial species, mediated by diffusible signal molecules. Although the intracellular regulatory mechanisms of QS are often well-understood, the functional roles of QS remain controversial. In particular, the use of multiple signals by many bacterial species poses a serious challenge to current functional theories. Here, we address this challenge by showing that bacteria can use multiple QS signals to infer both their social (density) and physical (mass-transfer) environment. Analytical and evolutionary simulation models show that the detection of, and response to, complex social/physical contrasts requires multiple signals with distinct half-lives and combinatorial (nonadditive) responses to signal concentrations. We test these predictions using the opportunistic pathogen Pseudomonas aeruginosa and demonstrate significant differences in signal decay betweeallyn its two primary signal molecules, as well as diverse combinatorial responses to dual-signal inputs. QS is associated with the control of secreted factors, and we show that secretome genes are preferentially controlled by synergistic “AND-gate” responses to multiple signal inputs, ensuring the effective expression of secreted factors in high-density and low mass-transfer environments. Our results support a new functional hypothesis for the use of multiple signals and, more generally, show that bacteria are capable of combinatorial communication

A Theoretical and Experimental Analysis of a Self-contained R-290 Refrigeration Unit Applied to a Glass Door Reach-in Supermarket Display Case

This paper presents a theoretical and experimental analysis of a self-contained variable speed R290 refrigeration unit applied to a typical 1.25m long two-glass-door reach-in supermarket display case, originally designed to run on an integrated R404a single speed refrigeration unit. A semi-empirical mathematical model was put forward to predict system energy consumption and cabinet psychometrics as a function of environmental conditions (ambient temperature and relative humidity), compressor model (single-speed, variable-speed and compressor displacement), refrigerant fluid (R290 and R404a) and geometry (heat exchangers overall heat transfer coefficient). One energy consumption test was performed at 32°C ambient temperature and used to calibrate components overall heat transfer coefficients. The model validation was then performed by using the calibrated model to predict the system energy consumption at 27°C ambient temperature. A good agreement between experimental and numerical results was found with errors lower than 1% and 3% on energy consumption and compressor running time ratio respectively. Finally, the model was applied to predict annual energy consumption for two units (R290 self-contained and R404a integrated) as a function of the monthly average ambient temperatures for Joinville, Santa Catarina, Brazil. The simulation results indicate an annual energy consumption saving up to 30% when a self-contained R290 variable speed hermetic refrigeration unit is applied to a cabinet originally designed for an integrated R404a single speed compressor refrigeration unit

Understanding the health and wellbeing challenges of the food banking system: A qualitative study of food bank users, providers and referrers in London.

In the UK, food poverty has been associated with conditions such as obesity, malnutrition, hypertension, iron deficiency, and impaired liver function. Food banks, the primary response to food poverty on the ground, typically rely on community referral and distribution systems that involve health and social care professionals and local authority public health teams. The perspectives of these key stakeholders remain underexplored. This paper reports on a qualitative study of the health and wellbeing challenges of food poverty and food banking in London. An ethnographic investigation of food bank staff and users was carried out alongside a series of healthcare stakeholder interviews. A total of 42 participants were interviewed. A Critical Grounded Theory (CGT) analysis revealed that contemporary lived experiences of food poverty are embedded within and symptomatic of extreme marginalisation, which in turn impacts upon health. Specifically, food poverty was conceptualised by participants to: firstly, be a barrier to providing adequate care and nutrition for young children; secondly, be exacerbated by lack of access to adequate fresh food, food storage and cooking facilities; and thirdly, amplify existing health and social problems. Further investigation of the local government structures and professional roles that both rely upon and serve to further embed the food banking system is necessary in order to understand the politics of changing welfare landscapes

Heat and moisture budgets from airborne measurements and high-resolution model simulations

High-resolution simulations with a mesoscale model are performed to estimate heat and moisture budgets of a well-mixed boundary layer. The model budgets are validated against energy budgets obtained from airborne measurements over heterogeneous terrain in Western Germany. Time rate of change, vertical divergence, and horizontal advection for an atmospheric column of air are estimated. Results show that the time trend of specific humidity exhibits some deficiencies, while the potential temperature trend is matched accurately. Furthermore, the simulated turbulent surface fluxes of sensible and latent heat are comparable to the measured fluxes, leading to similar values of the vertical divergence. The analysis of different horizontal model resolutions exhibits improved surface fluxes with increased resolution, a fact attributed to a reduced aggregation effect. Scale-interaction effects could be identified: while time trends and advection are strongly influenced by mesoscale forcing, the turbulent surface fluxes are mainly controlled by microscale processes

Gaming the system:Practices against the algorithmic makeover of everyday life

The introduction of technical, algorithmically-controlled interactive medial systems into virtually all contexts of everyday life is a relatively recent phenomenon. Implications, for instance, for social and political contexts are still emerging. One probably unexpected but certainly unintended effect is the emergence of gaming the system behaviours. Gaming is seen here as participants taking advantage of systems by interacting with them in unintended ways to gain unjustified benefits. These behaviours are regularly seen as problematic, and measures to prevent or to detect and to react to them are discussed in the academic discourse. This study aims to establish characteristics, practices and causes of such behaviours, exemplatory in the area of interactive, educational tutoring systems. The study is informed by positions from Game Studies, Cognitive Evaluation Theory (CET; Deci, Ryan) and the (post-) phenomenological discourse on the intentionality of non-human actors. It finds that users feel disenfranchised rather than empowered by the intentionality embodied in algorithmic systems; that those systems afford play; and that gaming behaviour can be read as defensive and evasive, rather than aggressive and criminal.The introduction of technical, algorithmically-controlled interactive medial systems into virtually all contexts of everyday life is a relatively recent phenomenon. Implications, for instance, for social and political contexts are still emerging. One probably unexpected but certainly unintended effect is the emergence of gaming the system behaviours. Gaming is seen here as participants taking advantage of systems by interacting with them in unintended ways to gain unjustified benefits. These behaviours are regularly seen as problematic, and measures to prevent or to detect and to react to them are discussed in the academic discourse. This study aims to establish characteristics, practices and causes of such behaviours, exemplatory in the area of interactive, educational tutoring systems. The study is informed by positions from Game Studies, Cognitive Evaluation Theory (CET; Deci, Ryan) and the (post-) phenomenological discourse on the intentionality of non-human actors. It finds that users feel disenfranchised rather than empowered by the intentionality embodied in algorithmic systems; that those systems afford play; and that gaming behaviour can be read as defensive and evasive, rather than aggressive and criminal

Short-Lived Trace Gases in the Surface Ocean and the Atmosphere

The two-way exchange of trace gases between the ocean and the atmosphere is important for both the chemistry and physics of the atmosphere and the biogeochemistry of the oceans, including the global cycling of elements. Here we review these exchanges and their importance for a range of gases whose lifetimes are generally short compared to the main greenhouse gases and which are, in most cases, more reactive than them. Gases considered include sulphur and related compounds, organohalogens, non-methane hydrocarbons, ozone, ammonia and related compounds, hydrogen and carbon monoxide. Finally, we stress the interactivity of the system, the importance of process understanding for modeling, the need for more extensive field measurements and their better seasonal coverage, the importance of inter-calibration exercises and finally the need to show the importance of air-sea exchanges for global cycling and how the field fits into the broader context of Earth System Science

A simple viability analysis for unicellular cyanobacteria using a new autofluorescence assay, automated microscopy, and ImageJ

<p>Abstract</p> <p>Background</p> <p>Currently established methods to identify viable and non-viable cells of cyanobacteria are either time-consuming (eg. plating) or preparation-intensive (eg. fluorescent staining). In this paper we present a new and fast viability assay for unicellular cyanobacteria, which uses red chlorophyll fluorescence and an unspecific green autofluorescence for the differentiation of viable and non-viable cells without the need of sample preparation.</p> <p>Results</p> <p>The viability assay for unicellular cyanobacteria using red and green autofluorescence was established and validated for the model organism <it>Synechocystis </it>sp. PCC 6803. Both autofluorescence signals could be observed simultaneously allowing a direct classification of viable and non-viable cells. The results were confirmed by plating/colony count, absorption spectra and chlorophyll measurements. The use of an automated fluorescence microscope and a novel ImageJ based image analysis plugin allow a semi-automated analysis.</p> <p>Conclusions</p> <p>The new method simplifies the process of viability analysis and allows a quick and accurate analysis. Furthermore results indicate that a combination of the new assay with absorption spectra or chlorophyll concentration measurements allows the estimation of the vitality of cells.</p

No severe and global X chromosome inactivation in meiotic male germline of Drosophila

This article is a response to Vibranovski et al