Alternative bacterial sigma factors bind the catalytic core RNA polymerase to confer promoter selectivity on the holoenzyme. The different holoenzymes are thus programmed to recognize the distinct promoter classes in the genome to allow coordinated activation of discrete sets of genes needed for adaptive responses. To form the holoenzymes, the different sigma factors must be available to compete for their common substrate (core RNA polymerase). This review highlights (a) the roles of antisigma factors in controlling the availability of alternative sigma factors and (b) the involvement of diverse regulatory molecules that promote the use of alternative sigma factors through subversion of the domineering housekeeping σ(70). The latter include the nucleotide alarmone ppGpp and small proteins (DksA, Rsd, and Crl), which directly target the transcriptional machinery to mediate their effects.
BackgroundThe use of an automated external defibrillator (AED) prior to EMS arrival can increase 30-day survival in out-of-hospital cardiac arrest (OHCA) significantly. Drones or unmanned aerial vehicles (UAV) can fly with high velocity and potentially transport devices such as AEDs to the site of OHCAs. The aim of this explorative study was to investigate the feasibility of a drone system in decreasing response time and delivering an AED.MethodsData of Global Positioning System (GPS) coordinates from historical OHCA in Stockholm County was used in a model using a Geographic Information System (GIS) to find suitable placements and visualize response times for the use of an AED equipped drone. Two different geographical models, urban and rural, were calculated using a multi-criteria evaluation (MCE) model. Test-flights with an AED were performed on these locations in rural areas.ResultsIn total, based on 3,165 retrospective OHCAs in Stockholm County between 2006–2013, twenty locations were identified for the potential placement of a drone.In a GIS-simulated model of urban OHCA, the drone arrived before EMS in 32 % of cases, and the mean amount of time saved was 1.5 min. In rural OHCA the drone arrived before EMS in 93 % of cases with a mean amount of time saved of 19 min. In these rural locations during (n = 13) test flights, latch-release of the AED from low altitude (3–4 m) or landing the drone on flat ground were the safest ways to deliver an AED to the bystander and were superior to parachute release.DiscussionThe difference in response time for EMS between urban and rural areas is substantial, as is the possible amount of time saved using this UAV-system. However, yet another technical device needs to fit into the chain of survival. We know nothing of how productive or even counterproductive this system might be in clinical reality.ConclusionsTo use drones in rural areas to deliver an AED in OHCA may be safe and feasible. Suitable placement of drone systems can be designed by using GIS models. The use of an AED equipped drone may have the potential to reduce time to defibrillation in OHCA.
Comparatively little is known about directed motility of environmental bacteria to common aromatic pollutants. Here, by expressing different parts of a (methyl)phenol-degradative pathway and the use of specific mutants, we show that taxis of Pseudomonas putida towards (methyl)phenols is dictated by its ability to catabolize the aromatic compound. Thus, in contrast to previously described chemoreceptor-mediated chemotaxis mechanisms towards benzoate, naphthalene and toluene, taxis in response to (methyl)phenols is mediated by metabolism-dependent behaviour. Here we show that P. putida differentially expresses three Aer-like receptors that are all polar-localized through interactions with CheA, and that inactivation of the most abundant Aer2 protein significantly decreases taxis towards phenolics. In addition, the participation of a sensory signal transduction protein composed of a PAS, a GGDEF and an EAL domain in motility towards these compounds is demonstrated. The results are discussed in the context of the versatility of metabolism-dependent coupling and the necessity for P. putida to integrate diverse metabolic signals from its native heterogeneous soil and water environments.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
The architectural design of the ICU has a great impact on nurses' well-being, work satisfaction and the provision of humanistic care. Nurses need to be involved in the process of planning and building new ICU settings. There is a need for further research to highlight the quality of physical environment and its impact on caring practice.
Phenomena in caring science are often complex and laden with meanings. Empirical research with the aim of capturing lived experiences is one way of revealing the complexity. Sometimes, however, results from empirical research need to be further discussed. One way is to further abstract the result and/or philosophically examine it. This has previously been performed and presented in scientific journals and doctoral theses, contributing to a greater understanding of phenomena in caring science. Although the intentions in many of these publications are laudable, the lack of methodological descriptions as well as a theoretical and systematic foundation can contribute to an ambiguity concerning how the results have emerged during the analysis. The aim of this paper is to describe the methodological support for the further abstraction of and/or philosophical examination of empirical findings. When trying to systematize the support procedures, we have used a reflective lifeworld research (RLR) approach. Based on the assumptions in RLR, this article will present methodological support for a theoretical examination that can include two stages. In the first stage, data from several (two or more) empirical results on an essential level are synthesized into a general structure. Sometimes the analysis ends with the general structure, but sometimes there is a need to proceed further. The second stage can then be a philosophical examination, in which the general structure is discussed in relation to a philosophical text, theory, or concept. It is important that the theories are brought in as the final stage after the completion of the analysis. Core dimensions of the described methodological support are, in accordance with RLR, openness, bridling, and reflection. The methodological support cannot be understood as fixed stages, but rather as a guiding light in the search for further meanings.
Bacteria swim and swarm using rotating flagella that are driven by a membrane-spanning motor complex. Performance of the flagella motility apparatus is modulated by the chemosensory signal transduction system to allow navigation through physico-chemical gradients – a process that can be fine-tuned by the bacterial second messenger c-di-GMP. We have previously analysed the Pseudomonas putida signalling protein PP2258 that has the capacity to both synthesize and degrade c-di-GMP. A PP2258 null mutant displays reduced motility, implicating the c-di-GMP signal originating from this protein in control of P. putida motility. In Escherichia coli and Salmonella, the PilZ-domain protein YcgR mediates c-di-GMP responsive control of motility through interaction with the flagellar motors. Here we provide genetic evidence that the P. putida protein PP4397 (also known as FlgZ), despite low sequence homology and a different genomic context to YcgR, functions as a c-di-GMP responsive link between the signal arising from PP2258 and alterations in swimming and swarming motility in P. putida.
SummaryHere the s-factor requirement for transcription of three similar, but differentially regulated, aer genes of Pseudomonas putida KT2440 is investigated. Previous work has shown that the three Aer proteins, like chemoreceptors, colocalize to a single pole in a CheA-dependent manner. Lack of Aer2 -the most abundant of these three proteins -mediates defects in metabolism-dependent taxis and aerotaxis, while lack of Aer1 or Aer3 has no apparent phenotype. We show, using wild-type and mutant P. putida derivatives combined with P. putida reconstituted FliA-(s 28 ) and s 70-dependent in vitro transcription assays, that transcription of aer2 is coupled to motility through the flagella s-factor FliA, while s 70 is responsible for transcription of aer1 and aer3. By comparing activities of the wild-type and mutant forms of the aer2 promoter, we present evidence (i) that transcription from FliAdependent Paer2 is enhanced by changes towards the Escherichia coli consensus for FliA promoters rather than towards that of P. putida, (ii) that the nature of the AT-rich upstream region is important for both output and s 70 discrimination of this promoter, and (iii) that Paer2 output is directly stimulated by the bacterial alarmone ppGpp and its cofactor DksA.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.