Weitere Untersuchungen über die Permeabilität von Beggiatoa Mirabilis

Schönfelder, Susanne

doi:10.1007/bf01948814

Cited by 45 publications

(2 citation statements)

References 56 publications

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“…(ii) The bacterium Beggiatoa mirabilis became a frequently cited extreme case on the basis of Ruhland's & Hoffmann's claim (122) that permeability was correlated solely with size and not at all with lipid :water K's. Examination of Schonfelder's more detailed study (123) shows that P does increase with K at constant M, and that Beggiatoa is unusual only in that the polar route passes molecules up to the size of disaccharides (diam eters ca. 10 A) , rather than cutting off around 3-carbon compounds (diam eters ca.…”

Section: (D)mentioning

confidence: 99%

Biological Membranes: The Physical Basis of Ion and Nonelectrolyte Selectivity

Diamond¹,

Wright²

1969

Annu. Rev. Physiol.

667

284

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Basic to the function of cell membranes is the ability to select between closely similar ions and molecules, such as potassium and sodium, calcium and magnesium, alcohols and aldehydes, and esters and acids. An under standing of the principles underlying selectivity is relevant to the study of neurophysiology, active transport, passive permeation, enzyme activation, and membrane structure. The present chapter has a twofold purpose : to summarize experimental evidence concerning the distinctive and consistent selectivity patterns exhibited by biol o gical membranes; and to review recent developments that have made it possible to account in large part for the main features of these patterns in terms of intermolecular and interatomic forces. Analyses of selectivity must begin by trying to explain as many phenomena as possible in terms of elementary physical concepts such as free energy, and in terms of the simplest principles governing the interactions of ions, such as Coulomb's law, or the simplest principles governing the interactions of non electrolytes, such as hydrogen bonding and van der Waals forces. While consideration of additional forces may prove necessary to interpret some more complex phenomena, explanations that do not take account even of the simplest forces cannot provide an adequate starting point. The first half of this chapter is devoted to ion selectivity, while the second half deals with nonelectrolyte selectivity.

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Section: (D)mentioning

confidence: 99%

Biological Membranes: The Physical Basis of Ion and Nonelectrolyte Selectivity

Diamond¹,

Wright²

1969

Annu. Rev. Physiol.

667

284

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“…For example, the alga Valonia ventricosa behaves as if it lacked pores (Gutknecht, 1968: a's for small polar solutes near 1.0, Poem and the diffusional water permeability Pd approximately equal, a's equal 1 -Psv,/Posm without a water-drag term); human erythrocyte behaves as if it had pores similar in size to those of rabbit gallbladder (Goldstein &Solomon, 1960, andSha'afi et al, 1967: Poem >Pal, a<l-P~ V~/Po,m implying a water-drag term, preferential permeability to small solutes up to the approximate size of malonamide) but smaller in size than those of dog erythrocyte (Rich e t al., 1967;Sha'afi et al, 1971); and the bacterium Beggiatoa rnirabilis (Ruhland & Hoffmann, 1925;Sch6nfelder, 1930), which is permeable to fully hydroxylated solutes up to the size of disaccharides, appears to have considerably larger pores than rabbit gallbladder. Similar co-variation appears in studies of nonelectrolyte permeation in single cells.…”

Section: Permeation Through Poresmentioning

confidence: 99%

Comparison of nonelectrolyte permeability patterns in several epithelia

Hingson

Diamond

1972

J. Membrain Biol.

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Reflection coefficients (~r's) have been determined for 13 to 36 nonelectrolytes in goldfish gallbladder, bullfrog gallbladder, bullfrog intestine, and guineapig intestine. These results have been compared with the results of similar previous studies in rabbit gallbladder, bullfrog choroid plexus, and guinea-pig gallbladder to determine types of species variation, organ variation, and individual variation. Two principal types of variation were established: (1) Branched solutes are much less permeant than straight-chain analogues in gallbladders of all four species studied, whereas this effect is small in intestine and negligible in choroid plexus. This variation in degree of discrimination against branched solutes is attributed to variation in closeness of packing of membrane lipids. (2) In certain epithelia, small polar solutes are more permeant than expected from their bulk nonpolar-solvent/water partition coefficients and from their size. This feature is very marked in rabbit gallbladder, somewhat marked in guineapig gallbladder and intestine and in bullfrog choroid plexus, apparent mainly just for formamide (the smallest polar nonelectrolyte) in bullfrog intestine, and virtually absent in goldfish and bullfrog gallbladders. Analysis of individual variability in preparations of guinea-pig intestine and rabbit gallbladder from different animals shows covariation in cr's of small polar nonelectrolytes uncorrelated with variation in o's of other solutes. Small polar solutes, in epithelia where their permeability is as expected from size and from nonpolar-solvent/water partition coefficients, resemble other solutes in having markedly temperature-dependent ~'s (high apparent activation energies of permeation), but have nearly temperature-independent a's (low activation energies, as for diffusion in aqueous solution) in epithelia where their permeability is enhanced. These findings suggest that additional size-restricted permeation pathways by-passing membrane lipid ("pores") are present in some tissues and smaller or virtually absen~ in others.

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The permeability of mammalian salivary glands for organic non‐electrolytes

Amberson

Höber

1932

J. Cell. Comp. Physiol.

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The phenomena of glandular activity fall into two categories. We have to do, first, with the formation of specific substances, not present in the blood, which are elaborated within the gland cells, and appear in the secretion. Secondly, we observe the performance of osmotic work, by which materials already present in the blood are either concentrated or diluted in the secretion. The glands thus appear to exercise a choice between various blood constituents, permitting only certain of them to penetrate, and often concentrating those which do. A full understanding of the secretion mechanism must include, therefore, a knowledge of the characteristics of gland tissue which determine its permeability. I n an attempt to study certain of these characteristics we have investigated the permeability of the mammalian salivary gland (cat) for various organic non-electrolytes.Previous studies on the permeability of this gland have established the following facts. As regards inorganic ions, a series of reports (Rosemann, '27 ; Babkin, '28 ; Gregersen and Ingalls, '31) have shown that K passes from the blood into the saliva more readily than Na. At the slower secretion rates more K than Na may be present in the saliva, and all workers agree that its concentration considerably exceeds that in the blood serum. Conversely, the Na content is always below that present in the serum. Gregersen and Ingalls have shown that the salivary Na content rises as the

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Weitere Untersuchungen über die Permeabilität von Beggiatoa Mirabilis

Cited by 45 publications

References 56 publications

Biological Membranes: The Physical Basis of Ion and Nonelectrolyte Selectivity

Biological Membranes: The Physical Basis of Ion and Nonelectrolyte Selectivity

Comparison of nonelectrolyte permeability patterns in several epithelia

The permeability of mammalian salivary glands for organic non‐electrolytes

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