THE EFFECT OF CHLORIDES OF MONOVALENT CATIONS, UREA, DETERGENTS, AND HEAT ON MORPHOLOGY AND THE TURBIDITY OF SUSPENSIONS OF RED HALOPHILIC BACTERIA

1961 ◽  
Vol 7 (5) ◽  
pp. 741-750 ◽  
Author(s):  
Dinah Abram ◽  
N. E. Gibbons

Suspensions of Halobacterium cutirubrum, grown and suspended in 4.0 M sodium chloride, showed on transfer to increasingly lower concentrations of sodium chloride an increase in turbidity followed by an abrupt decrease. When the suspensions were placed in potassium, rubidium, cesium, lithium, or ammonium chlorides, there was no increase in turbidity but usually a gradual decrease as the concentration of the salt is decreased. In potassium, rubidium, and cesium chlorides these changes were correlated with a change in morphology from rods, through transition forms, to spheres, similar to changes in NaCl, except that transition forms were found even at concentrations of 4.0 M. In lithium and ammonium chlorides there was an immediate change at 5.0 and 4.5 M respectively and two to five small spheres were formed from each rod. In mixtures of sodium and potassium chlorides the morphology of the cells depended on the ionic strength and concentration of sodium. Spheres were also produced by heating the cells to 60–70 °C, the time required for the conversion increasing with increasing salt concentration. In urea solutions the cells lysed, although at certain concentrations of urea and NaCl a change to small spheres was observed. Ionic detergents caused the cells to disintegrate gradually. These observations are taken as further evidence that sodium is required to maintain the cell wall of the red halophilic rods.

1960 ◽  
Vol 6 (5) ◽  
pp. 535-543 ◽  
Author(s):  
Dinah Abram ◽  
N. E. Gibbons

The optical densities of suspensions of cells of Halobacterium cutirubrum, H. halobium, or H. salinarium, grown in media containing 4.5 M sodium chloride, increase as the salt concentration of the suspending medium decreases, until a maximum is reached at about 2 M; below this concentration there is an abrupt decrease in optical density. The cells are rod shaped in 4.5 M salt and change, as the salt concentration decreases, through irregular transition forms to spheres; equal numbers of transition forms and spheres are present at the point of maximum turbidity, while spheres predominate at lower salt concentrations. Cells suspended in 3.0 M salt, although slightly swollen, are viable, but viability decreases rapidly with the more drastic changes in morphology at lower salt concentrations. Cells grown in the presence of iron are more resistant to morphological changes but follow the same sequence. Cells "fixed" with formaldehyde, at any point in the sequence, act as osmometers and do not rupture in distilled water although their volume increases 10–14 times. The results indicate that the red halophilic rods require a high sodium chloride content in their growth or suspending medium to maintain a rigid cell wall structure.


1957 ◽  
Vol 3 (5) ◽  
pp. 687-694 ◽  
Author(s):  
I. Takahashi ◽  
N. E. Gibbons

Labelled non-viscous cells of Micrococcus halodenitrificans were obtained in media containing P32 and 2 M sodium chloride and their growth then followed in salt concentrations ranging from 0.55 M, the lower limit of growth, to 3 M. At concentrations of 0.7 M and above, cells remained non-viscous and only traces of extracellular nucleic acids (NA) could be detected. At lower concentrations of salt, cells became viscous and the amount of extracellular NA increased as the concentration decreased. The distribution of P32 indicated that the source of the extracellular NA was intracellular. At the salt concentrations studied, the loss of NA was prevented by the addition of calcium or magnesium ions. However, sodium chloride seemed necessary to maintain the cell wall of M. halodenitrificans and the effect was supplemented by divalent ions. It is suggested that this may explain the salt requirement of this organism and possibly that of other halophilic bacteria.


1961 ◽  
Vol 7 (4) ◽  
pp. 483-489 ◽  
Author(s):  
N. E. Gibbons ◽  
John I. Payne

The red halophiles, Halobacterium salinarium, H. cutirubrum, H. halobium, and Sarcina litoralis, grew most rapidly at salt concentrations of 20–25% and temperatures of 40–45 °C. Maximum turbidity was obtained at similar salt concentrations but at 35–40 °C. An unidentified colorless rod grew most rapidly at salt concentrations of 17.5–20% and temperatures of 40–50 °C, but produced maximum yield at 30 °C. The rod forms changed from long slender rods through irregular shapes to spheres as the salt concentration was decreased. At temperatures above the optimum, cells were very irregular, but otherwise temperature at any one salt concentration had little or no effect on the morphology.


1954 ◽  
Vol 32 (1) ◽  
pp. 206-217 ◽  
Author(s):  
R. M. Baxter ◽  
N. E. Gibbons

Glycerol dehydrogenases from the extremely halophilic Pseudomonas salinaria and the moderately halophilic Vibrio costicolus are described and compared with the corresponding enzyme from the nonhalophilic Escherichia coli. The properties of all three enzymes are similar except their responses to salt concentration. The enzymes from E. coli and V. costicolus are most active at sodium chloride concentrations of about 0.25 M and 0.5 M respectively; that from P. salinaria is not only most active in the presence of 1.5 M NaCl but is irreversibly inactivated in the absence of salt. All three enzymes are more active in the presence of potassium chloride than of sodium chloride at any given molar concentration. These results suggest that the extremely halophilic bacteria contain high concentrations of salt and that their enzymes function maximally at these high concentrations. In contrast the moderately halophilic organisms contain relatively little salt and their enzymes are more comparable with those of nonhalophiles.


1954 ◽  
Vol 32 (3) ◽  
pp. 206-217 ◽  
Author(s):  
R. M. Baxter ◽  
N. E. Gibbons

Glycerol dehydrogenases from the extremely halophilic Pseudomonas salinaria and the moderately halophilic Vibrio costicolus are described and compared with the corresponding enzyme from the nonhalophilic Escherichia coli. The properties of all three enzymes are similar except their responses to salt concentration. The enzymes from E. coli and V. costicolus are most active at sodium chloride concentrations of about 0.25 M and 0.5 M respectively; that from P. salinaria is not only most active in the presence of 1.5 M NaCl but is irreversibly inactivated in the absence of salt. All three enzymes are more active in the presence of potassium chloride than of sodium chloride at any given molar concentration. These results suggest that the extremely halophilic bacteria contain high concentrations of salt and that their enzymes function maximally at these high concentrations. In contrast the moderately halophilic organisms contain relatively little salt and their enzymes are more comparable with those of nonhalophiles.


2017 ◽  
Vol 48 (1) ◽  
Author(s):  
Bahia & Naser

A laboratory experiment was carried out at the Department of Soil Sciences and Water Resources, College of Agriculture, University of Baghdad. Silty clay soil was treated with three salt solutions (NaCl, CaCl2 and mixed NaCl–CaCl2). Homogeneously packed soil columns (10 cm, 40 cm) were leached six times using tap water. Effluent samples were collected to determine ion concentration Cl-, Ca++, Na+, K+ and Mg++. Breakthrough curves were used to estimate solute transport parameters (retardation factor, peclet number) using an analytical solution of convection-dispersion equation (CDE) by CXTFIT program. The results showed that relative concentration of chloride was increased rapidly with calcium chloride, which increased sodium leaching rate at starting of breakthrough curve. Sodium chloride increased water requirements for calcium displacement. Results indicated a good fitting of convection-dispersion equation with breakthrough curves data. The best-fit were used to calculate peclet number, retardation factor and dispersion coefficient. When soil was treated with calcium chloride, Peclet number of chloride was increased from 3.13 to 6.48, while it has been decreased for calcium, sodium and potassium. Sodium chloride decreased peclet numbers of chloride, calcium and sodium. Also mixed salts increased sodium peclet number from 1.01 to 9.02. Results showed, calcium chloride decreased retardation factor of chloride from 1.59 to 0.50, while it has been increased from 1.39, 1.58 to 175.00, 493.36 for each of sodium and potassium, respectively. Retardation factor of calcium was decreased when soil was treated with sodium chloride or mixed salts. Dispersion coefficient was decreased for chloride, and increased for calcium and magnesium. When soil was treated with calcium chloride, dispersion coefficients have been increased from 24.29, 25.56 to 40.51, 40.89 cm2hr-1 for sodium and potassium, respectively.


1962 ◽  
Vol 15 (1) ◽  
pp. 39 ◽  
Author(s):  
H Greenway

Young barley plants, Hordeum vulgare cv. Chevron, were subjected to a sodium chloride concentration of 100 m-equiv/l. In a "continued" treatment, the salinity stress was maintained for 15 days. In a "removed" treatment, sodium chloride was removed from the substrate after 5 days, and the subsequent response was studied over a period of 10 days.


1982 ◽  
Vol 2 (4) ◽  
pp. 369-377
Author(s):  
F D Gillin ◽  
D S Reiner

The flagellated protozoan Giardia lamblia has been grown only in highly complex media under reduced oxygen tension. Therefore, the organic and physiological requirements for in vitro attachment and short-term (12-h) survival of this organism were determined. In defined maintenance media, a thiol reducing agent (e.g., cysteine) was absolutely required for attachment and survival of this aerotolerant anaerobe. The crude bovine serum Cohn III fraction greatly stimulated attachment and survival. Attachment was decreased at a reduced temperature (24 degrees C as compared with 35.5 degrees C) and absent at 12 degrees C or below. Attachment and survival were strongly dependent upon pH and ionic strength, with optima at pH 6.85 to 7.0 and 200 to 300 mosmol/kg. Sodium chloride was better tolerated than KC1. Reduction of Ca2+ and Mg2+ to below 10(-8) M did not significantly affect attachment.


Development ◽  
1968 ◽  
Vol 19 (3) ◽  
pp. 387-396
Author(s):  
Lester G. Barth ◽  
Lucena J. Barth

A study of the effects of a series of monovalent cations, Li+, Na+ and K+, and a series of divalent cations, Mn2+, Ca2+ and Mg2+, upon small aggregates of cells taken from the presumptive epidermis of Rana pipiens gastrulae revealed that these ions induce nerve and pigment cells (Barth, 1965). The effectiveness of both series of ions as inductors was similar to their effects on decreasing the electrophoretic mobility of DNA as determined by Ross & Scruggs (1964). When it was found that sucrose in glass-distilled water also would induce nerve and pigment cells the role of ions as inductors came under closer scrutiny. A study of the nature of the induction by sucrose revealed that a relatively high concentration of sodium ions was necessary in the culture medium used after sucrose treatment (Barth, 1966).


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