NAIP proteins are required for cytosolic detection of specific bacterial ligands in vivo.

NLRs (nucleotide-binding domain [NBD] leucine-rich repeat [LRR]-containing proteins) exhibit diverse functions in innate and adaptive immunity. NAIPs (NLR family, apoptosis inhibitory proteins) are NLRs that appear to function as cytosolic immunoreceptors for specific bacterial proteins, including flagellin and the inner rod and needle proteins of bacterial type III secretion systems (T3SSs). Despite strong biochemical evidence implicating NAIPs in specific detection of bacterial ligands, genetic evidence has been lacking. Here we report the use of CRISPR/Cas9 to generate Naip1(-/-) and Naip2(-/-) mice, as well as Naip1-6(Δ/Δ) mice lacking all functional Naip genes. By challenging Naip1(-/-) or Naip2(-/-) mice with specific bacterial ligands in vivo, we demonstrate that Naip1 is uniquely required to detect T3SS needle protein and Naip2 is uniquely required to detect T3SS inner rod protein, but neither Naip1 nor Naip2 is required for detection of flagellin. Previously generated Naip5(-/-) mice retain some residual responsiveness to flagellin in vivo, whereas Naip1-6(Δ/Δ) mice fail to respond to cytosolic flagellin, consistent with previous biochemical data implicating NAIP6 in flagellin detection. Our results provide genetic evidence that specific NAIP proteins function to detect specific bacterial proteins in vivo

Design of an alarm and risk management in chemistry. Some lessons learned from interdisciplinary research

International audienceIn this communication, we would like to contribute some elements from inderdisciplinary research whose purpose was to develop an aid system designed to prevent "chemical runaways" taking place along with their consequences at human level (death), environmental level (SEVESO type companies) and industrial level (destruction of installations). This project follows an inquiry we made into a chemical runaway in a nuclear plant in 1994. The accident was fatal for one operator. In this case, two hours before the explosion, the operators realised that something was wrong. The five operators tried to get out of the unit a few seconds before the explosion. This type of result (which was largely confirmed by other analyses) shows that process operators often think that the time they have before an explosion is more than it really is. Our aim was the design of a system that would warn operators of the arrival of a chemical runaway and would predict the time remaining until an imminent explosion

A Novel Silicon Micromachined Integrated MCM Thermal Management System

"Micromachining" is a chemical means of etching three-dimensional structures, typically in single- crystalline silicon. These techniques are leading toward what is coming to be referred to as MEMS (Micro Electro Mechanical Systems), where in addition to the ordinary two-dimensional (planar) microelectronics, it is possible to build three-dimensional n-ticromotors, electrically- actuated raicrovalves, hydraulic systems and much more on the same microchip. These techniques become possible because of differential etching rates of various crystallographic planes and materials used for semiconductor n-ticrofabfication. The University of Cincinnati group in collaboration with Karl Baker at NASA Lewis were the first to form micro heat pipes in silicon by the above techniques. Current work now in progress using MEMS technology is now directed towards the development of the next generation in MCM (Multi Chip Module) packaging. Here we propose to develop a complete electronic thermal management system which will allow densifica6on in chip stacking by perhaps two orders of magnitude. Furthermore the proposed technique will allow ordinary conu-nercial integrated chips to be utilized. Basically, the new technique involves etching square holes into a silicon substrate and then inserting and bonding commercially available integrated chips into these holes. For example, over a 100 1/4 in. by 1 /4 in. integrated chips can be placed on a 4 in. by 4 in. silicon substrate to form a Multi-Chip Module (MCM). Placing these MCM's in-line within an integrated rack then allows for three-diniensional stacking. Increased miniaturization of microelectronic circuits will lead to very high local heat fluxes. A high performance thermal management system will be specifically designed to remove the generated energy. More specifically, a compact heat exchanger with milli / microchannels will be developed and tested to remove the heat through the back side of this MCM assembly for moderate and high heat flux applications, respectively. The high heat load application of particular interest in mind is the motor controller developed by Martin Marietta for Nasa to control the thruster's directional actuators on space vechicles. Work is also proposed to develop highly advanced and improved porous wick structures for use in advanced heat loops. The porous wick will be micromachined from silicon using MEMS technology, thus permitting far superior control of pore size and pore distribution (over wicks made from sintered n-ietals), which in turn is expected to led to significantly improved heat loop performance

Ergonomic Analysis of Veterinary Surgical Tasks

Studies have observed injuries and musculoskeletal discomforts among surgeons in human medicine. It is likely that veterinary surgeons endure similar discomfort; however, limited work has been done in this domain. Therefore, this research aims to identify occupational risk factors affecting the upper extremities of leading and assisting surgeons in orthopedic and soft tissue small animal surgeries. As a result, we aim to reduce surgeon injuries by assessing the surgical environment in veterinary care. To collect objective metrics, inertial measurement units (IMUs), heart rate monitors, and Electromyography (EMG) sensors are used. In addition, surveys are used to evaluate perceived pain before and after surgery and the workload of the task. In total, 5 participants were studied over 26 surgeries. Postoperatively, neck discomfort was most commonly recorded. Neck discomfort was reported in two-thirds of the cases by of the orthopedic surgeons and over one-third of the soft tissue surgeries. Average perceived workload was reported higher in orthopedic surgeries compared to soft tissue surgeries. When measuring the deltoid and trapezius muscle activities, orthopedic surgeons exerted about 21% of their maximum muscle force across the two muscle groups and soft tissue surgeons exerted 12%. These results provide insight to surgeons\u27 perceived workload and physical efforts associated with performing surgery, and further applications of this work may translate to modifications to surgical environments or additional surgeon education to reduce physical strains

An \u3cem\u3eEscherichia coli\u3c/em\u3e Nissle 1917 Missense Mutant Colonizes the Streptomycin-Treated Mouse Intestine Better than the Wild Type but Is Not a Better Probiotic

Previously we reported that the streptomycin-treated mouse intestine selected for two different Escherichia coli MG1655 mutants with improved colonizing ability: nonmotile E. coli MG1655 flhDC deletion mutants that grew 15% faster in vitro in mouse cecal mucus and motile E. coli MG1655 envZ missense mutants that grew slower in vitro in mouse cecal mucus yet were able to cocolonize with the faster-growing flhDC mutants. The E. coli MG1655 envZ gene encodes a histidine kinase that is a member of the envZ-ompR two-component signal transduction system, which regulates outer membrane protein profiles. In the present investigation, the envZ P41L gene was transferred from the intestinally selected E. coli MG1655 mutant to E. coli Nissle 1917, a human probiotic strain used to treat gastrointestinal infections. Both the E. coli MG1655 and E. coli Nissle 1917 strains containing envZ P41L produced more phosphorylated OmpR than their parents. The E. coli Nissle 1917 strain containing envZ P41L also became more resistant to bile salts and colicin V and grew 50% slower in vitro in mucus and 15% to 30% slower on several sugars present in mucus, yet it was a 10-fold better colonizer than E. coli Nissle 1917. However, E. coli Nissle 1917 envZ P41L was not better at preventing colonization by enterohemorrhagic E. coli EDL933. The data can be explained according to our “restaurant” hypothesis for commensal E. coli strains, i.e., that they colonize the intestine as sessile members of mixed biofilms, obtaining the sugars they need for growth locally, but compete for sugars with invading E. coli pathogens planktonically

Phytoplankton calcification as an effective mechanism to prevent cellular calcium poisoning

Marine phytoplankton have developed the remarkable ability to tightly regulate the concentration of free calcium ions in the intracellular cytosol at a level of ~ 0.1 μmol L−1 in the presence of seawater Ca2+ concentrations of 10 mmol L−1. The low cytosolic calcium ion concentration is of utmost importance for proper cell signalling function. While the regulatory mechanisms responsible for the tight control of intracellular Ca2+ concentration are not completely understood, phytoplankton taxonomic groups appear to have evolved different strategies, which may affect their ability to cope with changes in seawater Ca2+ concentrations in their environment on geological timescales. For example, the Cretaceous (145 to 66 Ma), an era known for the high abundance of coccolithophores and the production of enormous calcium carbonate deposits, exhibited seawater calcium concentrations up to 4 times present-day levels. We show that calcifying coccolithophore species (Emiliania huxleyi, Gephyrocapsa oceanica and Coccolithus braarudii) are able to maintain their relative fitness (in terms of growth rate and photosynthesis) at simulated Cretaceous seawater calcium concentrations, whereas these rates are severely reduced under these conditions in some non-calcareous phytoplankton species (Chaetoceros sp., Ceratoneis closterium and Heterosigma akashiwo). Most notably, this also applies to a non-calcifying strain of E. huxleyi which displays a calcium sensitivity similar to the non-calcareous species. We hypothesize that the process of calcification in coccolithophores provides an efficient mechanism to alleviate cellular calcium poisoning and thereby offered a potential key evolutionary advantage, responsible for the proliferation of coccolithophores during times of high seawater calcium concentrations. The exact function of calcification and the reason behind the highly ornate physical structures of coccoliths remain elusive

Activated mutant NRasQ61K drives aberrant melanocyte signaling, survival, and invasiveness via a rac1-Dependent mechanism

Around a fifth of melanomas exhibit an activating mutation in the oncogene NRas that confers constitutive signaling to proliferation and promotes tumor initiation. NRas signals downstream of the major melanocyte tyrosine kinase receptor c-kit and activated NRas results in increased signaling via the extracellular signal–regulated kinase (ERK)/MAPK/ERK kinase/mitogen-activated protein kinase (MAPK) pathways to enhance proliferation. The Ras oncogene also activates signaling via the related Rho GTPase Rac1, which can mediate growth, survival, and motility signaling. We tested the effects of activated NRasQ61K on the proliferation, motility, and invasiveness of melanoblasts and melanocytes in the developing mouse and ex vivo explant culture as well as in a melanoma transplant model. We find an important role for Rac1 downstream of NRasQ61K in mediating dermal melanocyte survival in vivo in mouse, but surprisingly NRasQ61K does not appear to affect melanoblast motility or proliferation during mouse embryogenesis. We also show that genetic deletion or pharmacological inhibition of Rac1 in NRasQ61K induced melanoma suppresses tumor growth, lymph node spread, and tumor cell invasiveness, suggesting a potential value for Rac1 as a therapeutic target for activated NRas-driven tumor growth and invasiveness

Occupational Risks during a Monkeypox Outbreak, Wisconsin, 2003

Veterinary staff were at high risk; standard veterinary infection-control guidelines should be followed

Bacterial Stress Responses: What Doesn't Kill Them Can Make Them Stronger

Identifying specific mechanisms that contribute to microbial survival under rapidly changing conditions could provide insight into stress response systems across life forms