Drugs and certain proteins are transported across the membranes of Gram-negative bacteria by energy-activated pumps. The outer membrane component of these pumps is a channel that opens from a sealed resting state during the transport process. We describe two crystal structures of the Escherichia coli outer membrane protein TolC in its partially open state. Opening is accompanied by the exposure...

An automated apparatus to assist in the development of analytical continuous flow methods is described. The system is capable of controlling and monitoring a variety of pumps, valves, and detectors through an IBM PC-AT compatible computer. System components consist of two types of peristaltic pumps (including a multiple pump unit), syringe pumps, electrically and pneumatically actuated valves, ...

The fluid flow control systems can be classified depending on the type of pressure source, on the pipe system structure and on the control element. Depending on the pressure source type, the flow control systems can be equipped with centrifugal pumps or volumetric pumps. Concerning the pipe structure, the flow control systems can be used within the hydraulic systems with branches or without bra...

Clinically important resistance of fungal pathogens to azole antifungal drugs is most frequently caused by the over-expression of energy-dependent drug efflux pumps. These pumps usually belong to either the ATP-binding cassette (ABC) family or the Major Facilitator Superfamily (MFS) class of membrane transporter. Little is known about how these pumps work and there is an urgent need to develop ...

In Pseudomonas putida DOT-T1E multidrug efflux pumps of the resistance-nodulation-division family make a major contribution to solvent resistance. Two pumps have been identified: TtgABC, expressed constitutively, and TtgDEF, induced by aromatic hydrocarbons. A double mutant lacking both efflux pumps was able to survive a sudden toluene shock if and only if preinduced with small amounts of tolue...

Current biofuel production methods use engineered bacteria to break down cellulose and convert it to biofuel. A major challenge in microbial fuel production is that increasing biofuel yields can be limited by the toxicity of the biofuel to the organism that is producing it. Previous research has demonstrated that efflux pumps are effective at increasing tolerance to various biofuels. However, w...

Three centrifugal flow pumps; the Biomedicus BP80, the Sarns Delphin and the Aries Lifestream 2100, were evaluated in vitro to determine each pump's individual tendencies for thrombus formation. Thrombogenic surfaces in the circuit were minimized by using heparin coated tubing and connectors. The centrifugal pumps, which were not heparin bonded, were placed in line in a circuit which consisted ...

We show that a reversible pumping mechanism operating between two states of a kinetic network can give rise to Poisson transitions between these two states. An external observer, for whom the pumping mechanism is not accessible, will observe a Markov chain satisfying local detailed balance with an emerging effective force induced by the hidden pump. Due to the reversibility of the pump, the act...

BACKGROUND While multiple daily insulin injections remains the state-of-the-art treatment for type 1 diabetes, continuous subcutaneous insulin infusion (CSII) has become increasingly popular in recent years. Up to 40% of people with type 1 diabetes in younger age groups are now using CSII. Very recently, continuous glucose monitoring (CGM) has been developed. This technology now has proven bene...

We have previously suggested that the cyclic electron-transport chain in Rhodopseudomonas sphaeroides and Rhodopseudomonas capsulata is arranged as two proton pumps operating in series, one pump being associated with the photochemical reaction centre and its immediate secondary donor (cytochrome c2) and acceptor (ubiquinone), and the other with the 'dark' electron transport through which the cy...