Resistance Pumps

The occurrence of MFS-type MDR efflux pumps in LAB is much higher than in most other bacteria as noted in Section 4.3. For example, LAB have over 60% of their MFS carriers functioning as MDR/hydrophobic compound exporters compared to 40-50% for otha- bactraia (Table 4.3 Lorca et al. 2007), thus showing an unexpected trend. Moreover, in most LAB, MFS porters predominate MFS (55%) ABC (32%) MOP (7%) RND (4%) DMT (2%). However, in Strep, thermophi-lus, the order is MOP (47%) ABC (37%) MFS (16%) RND or DMT, and in Lact. delbruekii and Lact. gasseri these ratios are ABC (51%) MFS (44%) RND ( 5%) MOP or DMT (0%). It is therefore clear that while LAB exhibit unusual trends relative to other bacteria, they sometimes exhibit considerable variation among themselves. 

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Concentrate recycle RO plants allow some of the brine reject water to recycle back through the plant, which improves the permeate recovery rate. (The reduced flow of brine reject water does of course have a proportionally higher TDS level.) Various types of high pressure, corrosion-resistant pumps are used, including multistage, centrifugal and plunger pumps, each with their own benefits and area of application. 

Biochemical mechanisms of resistance 3.5 Multidrug resistance pumps... 

ULTRALEN is a polyphenylether. This fluid is recommended in all those cases where a particularly oxidation-resistant pump fluid must be used and where siiicone oiis wouid interfere with the process. 

Fig. 6.2. Internal-vane, external-vane, and plunger-type rotary vacuum pumps. It will be noted that the internal-vane pump involves a rotor concentric with the drive shaft, but which is off-center with respect to the stator. By contrast, the external-vane and rotary-plunger pumps have a rotor which is asymmetric with respect to the shaft however, the shaft is centered in the stator. All three involve close tolerances, so the high-vacuum performance is impaired by particles of dirt or corrosive gases. Some pumps are partially constructed from soft die-cast metal, which is eroded by mercury. Special corrosion-resistant pumps and inert flourinated pumps are used in the semiconductor industry.

Special corrosion-resistant pumps are now widely used in the semiconductor industry. Often these are equipped with pump oil purifiers and are never turned off when contaminants are present. These pumps are expensive and under harsh conditions they break down much more often than a well-protected conventional pump. 

Various types of high-pressure, corrosion-resistant pump are used, including multistage, centrifugal, and plunger pumps, each with its own benefits and area of application. 

Wigler, P.W. and F.K. Patterson. 1994. Reversal agent inhibition of the multidrug resistance pump in human leukemic lymphoblasts. Biochim Biophys Acta 1189 (1) 1. 

Little is known of the ways of biosynthesis and insertion in the membranes of PolyP-PHB-Ca2+ complexes. In polyphosphate kinase 1 mutants of E. coli, the amounts of the complexes did not change (Castuma et al., 1995). Therefore, the PolyP in the complexes is synthesized not by polyphosphate kinase 1 but by another enzyme. E. coli strain, which lacks the AcrA component of a major multi-drug resistance pump, had greatly reduced amounts of the complexes and was defective in its ability to maintain sub-micromolar levels of free Ca2+ in the cytoplasm (Jones et al., 2003). This indicates that the AcrAB transporter may have a novel, hitherto undetected, physiological role, either directly in the membrane assembly of the PHB complexes or the transport of a component of the membrane, which is essential for assembly of the complexes into the membrane. 

Ambudkar SV, Lelong IH, Zhang J, Cardarelli CO, Gottesman MM, Pastan I (1992) Partial purification and reconstitution of the human multidrug-resistance pump characterization of the drug-stimulatable ATP hydrolysis. Proc Natl Acad Sci USA 89 8472-8476... 

Lacroix EJ, Cloeckaert A, Grepinet O, Pinault C, Popoff MY, Waxin H, Pardon P. Salmonella typhimurium acrB-like gene identification and role in resistance to biliary salts and detergents and in murine infection. EEMS Microbiol. Lett. 1996 135 161-167. Colmer JA, Eralick JA, Hamood AN. Isolation and characterization of a putative multidrag resistance pump from Vibrio cholerae. Mol. Microbiol. 1998 27 63-72. 

Xu C, Rosen BP. Metalloregulation of soft metal resistance pumps. In Metals and Genetics. Sarkar B, ed. 1999. Kluwer Aca-demic/Plenum publishers. New York. pp. 5—19. 

The deodorized coconut oil flows down to the drop tank and holding chamber of the distilling column. Residence time in the deodorizer ranges from 1.5 h to 2 h. The oil from the column is withdrawn by a hermetically sealed and heat-resistant pump and conveyed to the economizer, which preheats the incoming deodorizer feedstock. The oil is cooled down to 50°C, at which temperature citric acid is added. Citric acid enhances the stability of oil by immobilizing iron and copper, which are pro-oxidants. (Note The deodorization step is omitted in the production of Cochin oil.)... 

The spectrum of this zeolite is more complicated, In the OH stretching region three bands were observed after pretreatment at 573 or 673 K, at 3750, 3620 and 3540 cm", the former two resist pumping at 973 K, when the last one disappears. After CO adsorption at 77 K (fig. 2.) these bands diminish while two bands of perturbed hydroxyls show up at 3660 and 3330 cm . That at 3660 cm disappears after pumping off the gaseous CO at 77 K together with the band of adsorbed CO at 2160 cm and the restoration of the 3750 cm band, however, to remove all the CO bands and to recover the initial OH group spectrum, evacuation at room temperature is needed. 

NATURAL PRODUCTS AS MULTIDRUG RESISTANCE PUMP (MDR) INHIBITORS... 

A new method of bioactivity-directed fractionation, based on multidrug resistant pump (MDR) inhibition in Staphylococcus aureus, was reported for medicinal plants. This work resulted in the isolation, from berberine-containing Berberis species, two compounds that are themselves devoid of antibacterial activity, but that form potent synergistic couples with a sub-inhibitory concentration of berberine. The bacterial MDR pump inhibitors were identified as the flavonolignan 2 and the porphyrin 3 [98]. The isoflavones not only enhanced the antibacterial activity of the natural product, berberine. Fig. 4, but also the activity of synthetic... 

Bioassay-guided fractionation of an extract of Artemisia annua was conducted in order to assess the possible presence in the plant material of inhibitors of bacterial multidrug resistance pumps [218]. Fractions were tested for Staphylococcus aureus growth inhibition in the presence of a subinhibitory dose of weak antibacterial alkaloid berberine. Active fractions yielded the flavones chrysoplenol D and chrysoplenetin,... 

Analysis of organic compounds using ICP-OES requires higher radio frequency power, a suitable nebuliser spray chamber and solvent resistant pump tubing for transporting the sample solution using a peristaltic pump. 

Chung, Y.J. and Saier, M.H., Jr. (2001) SMR-type multidrug resistance pumps. Current Opinion in Drug Discovery eC Development, 4 (2), 237-245. 

RND)-type multidrug resistance pumps the large periplasmic loops of MexD from Pseudomonas aeruginosa are involved in substrate recognition. Molecular Microbiology, 46 (3), 889-901. 

Ferreha, M.M.C. and Kiralj, R. (2004) QSAR study of p-lactam antibiotic efflux by the bacterial multidmg resistance pump AcrB./. Chemom., 18, 242-252. 

Treutter [151,154] analyzed procyanidin condensation products after post-column derivatization with dimethylaminocinnamaldehyde. Intensive studies on reaction kinetics [154], linearity [154], sensitivity [235] as well as on cross reactivity [151] have been performed. The method has been used to assay procyanidins in apple tissue [93], cherry tissue [248] and wine [235] other matrices have been analyzed qualitatively [44,153,249]. The main disadvantage of this method is the requirement of special equipment (knitted reaction coil, acid-resistant pump, easy-to-clean flow cell). 

Lewis, K. (1994). Multidrug resistance pumps in bacteria Variations on a theme. Trends Bio-chem. Sci. 19, 119-123. 

C Xu, BP Rosen. MetaUoregulation of soft metal resistance pumps. In B Sarkar, ed. Metals and Genes. New York Plenum, 1999, p 406. 

T Zhou, S Radaev, BP Rosen, DL Gatti. Structure of the ArsA ATPase The catalytic subunit of a heavy metal resistance pump. EMBO J 19 4838-4845, 2000. 

Poget SF, Cahill SM, Girvin ME (2007) Isotropic bicelles stabilize the functional form of a small multidrug-resistance pump for NMR structural studies. J Am Chem Soc 129 2432-2433... 

Organic solvents are used quite frequently in FI separation systems, but most of them cannot be pumped through the tygon pump tubes used most often with peristaltic pumps, at least not for extended periods. Several choices of solvent resistant pump tubes, such as the Solvaflex, Verdoprene, Neoprene, Marprene and Viton pump tubes, are available, and... 

Computerized automated FI solution processing system widi two variable speed peristaltic pumps and a 4 S channel injector valve, all separately programmable in seven steps, lygon pump tubes are used for all solutions except ethanol, which must be delivered by a solvent resistant pump tube (e.g. Verdoprene or Matprene). 

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