Cell wall permeability

Vancomycin (Vancocin) acts against susceptible gram-positive bacteria by inhibiting bacterial cell wall synthesis and increasing cell wall permeability. This drug is used in the treatment of serious gram-positive infections that do not respond to treatment with other anti-infectives. It also may be used in treating anti-infective-associated pseudomembranous colitis caused by Clostridium difficile. 

Uses Candidiasis tinea Infxns Action Antifungal alters cell wall permeability Dose PO Prophylaxis One troche dissolved in mouth tid Rx 1 troche dissolved in mouth 5 x d for 14 d Vag 1% cream 1 applicator full hs for 7 d 2% cream 1 applicator full hs for 3 d Tabs 100 mg vaginally hs for 7 d or 200 mg (2 tabs) vaginally hs for 3 d or 500-mg tabs vaginally hs once Topical Apply bid 10—14 d Caution [B, (C if PO), ] Not for systemic fungal Infxn Contra Component allergy Disp Cream, soln, lotion, vag tabs, vag cream SE Topical Local irritation PO N/V Interactions T Effects OF cyclosporine, tacrolimus X- effects OF spermicides EMS None OD Unlikely... 

The q-space imaging method, which deals with signals only after long diffusion times, discards all information relevant to dynamic aspects of water diffusion and transport, especially the restriction of water transport by membrane and cell wall permeability barriers in cellular tissues. This information is contained in the functional dependence of the pulsed gradient spin echo amplitude S(q,A,x) on the three independent variables q, A, and x (x is the 90-180 degree pulse spacing) [53]. As the tool to explore the q and A dependence of S(q,A,x), generalized diffusion times and their associated fractional populations are introduced and a multiple exponential time series expansion is used to analyze the dependence [53]. 

The chemical modification of the peptide antibiotic J25 also involves the use of a carbodiimide. " The crosslinking of the major porin MspA of Microbacterium smegmatis is accomplished with EDC to crosslink carboxyl groups. The crosslinking limits the cell wall permeability of the microbacterium. ... 

Fluoroquinolones must penetrate bacteria to reach their target, DNA gyrase. The second mechanism of fluoroquinolone resistance is decreased cell wall permeability. The fluoroquinolones diffuse through porin channels in the outer membrane of Gram-negative bacteria. Mutation results in a decrease in porin channel proteins, resulting in decreased uptake of the fluoroquinolones into bacterial cells. Alterations in a wide range of outer membrane proteins in Pseudomonas spp. result in resistance. From these mutations, the increase in MIC of the fluoroquinolones is relatively low (2-to 32-fold). Flowever, there is cross-resistance with unrelated antibiotics, most frequently cefoxitin, chloramphenicol, trimethoprim and tetracycline. 

Huijghebaert et al. [23] isolated a bile salt sulfatase-producing strain designated, Clostridium S, from rat feces. This bacterium hydrolyzed the 3-sulfates of lithocholic acid, chenodeoxycholic acid, deoxycholic acid and cholic acid but not the 7-or 12-monosulfates. Sulfatase activity required the 3-sulfate group to be in the equatorial position. A free C-24 or C-26 carboxyl group was also required for sulfatase activity in whole cells of this bacterium. The 3-sulfate of cholesterol, Cj,-and Cji-steroids were not hydrolyzed by Clostridium S, [24]. Nevertheless, C,9- and C2]-steroid sulfates are hydrolyzed in the gut by microbial activity suggesting that the intestinal microflora may contain bacteria with steroid sulfatases possessing different substrate specificities. However, it should be noted that enzyme substrate specificity studies carried out in whole cells may reflect both cell wall permeability and enzyme specificity. 

Histamine was discovered in 1910 and is released from cells when they are injured. An injured cell also stimulates production of histamine by the action of histadine carboxylase. The freed histamine causes capillaries to dilate and smooth muscles to contract. This results in a reddening of the area, itching or pain by a reaction with nerve endings, and a local edema from increased cell wall permeability. 

Oxytetracycline hydrochloride is an antibiotic that inhibits bacterial protein synthesis. Polymyxin B interacts with phospholipid components of bacterial cell membrane, increasing cell wall permeability. It is indicated in the treatment of superficial ocular infections involving the conjunctiva and/or cornea caused by susceptible organisms. 

It is also becoming increasingly apparent that the specific chemical form of a metal is a factor in its toxicity. Water-lipid partitioning, cell-wall permeability, and metabolic transport are just a few of the factors influenced by chemical form which, in turn, influence toxicity. Hexavalent chromium, pentavalent vanadium, divalent manganese, arsine, and methylmercury are more toxic than other forms of the corresponding metal. ... 

An eqnation has been derived relating the effective diffusivity of porous foodstuffs to various physical properties such as molecular weight, bulk density, vapor space permeability, water activity as a function of material moisture content, water vapor pressure, thermal conductivity, heat of sorption, and tanperature [80]. A predictive model has been proposed to obtain effective diffusivities in cellular foods. The method requires data for composition, binary molecular diffusivities, densities, membrane and cell wall permeabilities, molecular weights, and water viscosity and molar volume [81]. The effect of moisture upon the effective diffusivity is taken into account via the binding energy of sorption in an equation suggested in Ref. [77]. 

High-intensity electric field pulses accelerated osmotic dehydration of carrot [18], A Fickian diffusion coefficient for water and solute increased exponentially with electric field strength. This effect was attributed to increased cell wall permeability, which was also manifested by the softening of product. 

Powell (1967) compared these functions and elaborated another equation, taking into account cell wall permeability, substrate diffusion, and cell size by a factor Kj (see Fig. 5.74) ... 

Rose CP, Goresky CA, Bach GG (1977) The capillary and sarcolemmal barriers in the heart - An exploration of labeled water permeability. Circ Res 41 515-533 Tancredi RG, Yipintsoi T, Bassingthwaighte JB (1975) Capillary and cell wall permeability to potassium in isolated dog hearts. Am J Physiol 229 537-544 Yipintsoi T, Dobbs Jr WA, Scanlon PD, Knopp TJ, Bassingthwaighte JB (1973) Regional distribution of diffusible tracers and carbonized microspheres in the left ventricle of isolated dog hearts. Circ Res 33 573-587... 

It shall be recalled that the M of Invertase and acid phosphatase Is about 250 kDa and the M of the Internalized alkaline phosphatase Is 60 kDa. To explain the discrepancy between the values of the cell wall permeability measured experimentally and the actually observed export and Import of macromolecules, we put forward the following proposal ... 

Fig. 4. Cell wall permeability of S.cerevisiae Y-350 grown in + ex ( ) and - ex (o) conditions. Sv - periplasmic space volume.

Several mechanisms have been proposed to explain the antimicrobial properties of tannins. The antimicrobial effects of phenolic compounds are probably related to the inhibition of bacterial enzymes, alterations in cell wall permeability, an increase in the hydrogen ion activity of the microbial environment, a reduction in the surface and/or interfacial tension and perhaps chelation of essential minerals, particularly iron with a concomitant impairment of the microbial oxidative metabolic system (Chung et al. 1998). The antimicrobial activities of tannins are ascribed to the interactions of goats tannins with the extracellular enzymes secreted and... 

Calehim Builds and maintains bones and teeth blood clotting, muscles coniraction and relaxation, cell wall permeability enzyme activation and nerve transnrlssion. Milk add milk produds, most nuls. dried figs, fish with soft edible bones, and green laaly yegeiablea. 

Just as flavonoids, anthocyanosides reduce the capillaries permeability and increase their resistance. The activity of these heterosides seems to be related to the function of collagen in cell-wall permeability. 

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