Resistance altered transport

AMINOGLYCOSIDE RESISTANCE BY ALTERED TRANSPORT 3.3.1. Import Mechanisms... 

Antibiotic resistance can be the result of several molecular mechanisms (Table 1). Some of the most important of these mechanisms include enzyme-catalyzed antibiotic inactivation or modification, altered transport such as efflux, and others such as metabolic bypass and sequestration. Each of these mechanisms requires the synthesis of associated proteins to mediate resistance. These are often highly specialized and efficient, and frequently the corresponding genes can be acquired on mobile... 

Tutulan-Cunita, A.C., Mikoshi. M.. Mizunuma, M.. Hirata, D., and Miyakawa, T. (2005) Mutational analysis of the yeast multidrug resistance ABC transporter PdrSp with altered diug specificity. Genes to Cells, 10, 409-420. 

The transient response of DMFC is inherently slower and consequently the performance is worse than that of the hydrogen fuel cell, since the electrochemical oxidation kinetics of methanol are inherently slower due to intermediates formed during methanol oxidation [3]. Since the methanol solution should penetrate a diffusion layer toward the anode catalyst layer for oxidation, it is inevitable for the DMFC to experience the hi mass transport resistance. The carbon dioxide produced as the result of the oxidation reaction of methanol could also partly block the narrow flow path to be more difScult for the methanol to diflhise toward the catalyst. All these resistances and limitations can alter the cell characteristics and the power output when the cell is operated under variable load conditions. Especially when the DMFC stack is considered, the fluid dynamics inside the fuel cell stack is more complicated and so the transient stack performance could be more dependent of the variable load conditions. 

A second mechanism of acquired resistance to fosfomycin involves chromosomal mutations in sugar phosphate uptake pathways which are responsible for transporting fosfomycin into the cell. The alterations decrease accumulation of the antibiotic to levels below those required for inhibition. 

A high sodium intake and increased circulating natriuretic hormone inhibition of intracellular sodium transport, resulting in increased vascular reactivity and a rise in BP and / Increased intracellular concentration of calcium, leading to altered vascular smooth muscle function and increased peripheral vascular resistance. 

Morgan PF, Fine RL, Montgomery P, Marangos PJ (1991) Mdtidrug resistance in MCF-7 human breast cancer c s is associated with increased expression of nucleoside transporters and altered uptake of adenosine. Cancer Chemother Pharmacol 29 127-132... 

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