RELATION OF TEMPERATURE AND SODIUM CHLORIDE CONCENTRATION TO GROWTH AND MORPHOLOGY OF SOME 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.

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.


1971 ◽  
Vol 121 (4) ◽  
pp. 629-633 ◽  
Author(s):  
B. Gregory Louis ◽  
P. S. Fitt

1. Crude extracts of the extreme halophile Halobacterium cutirubrum contain separable DNA-dependent and RNA-dependent RNA polymerases. 2. The RNA-dependent enzyme has been purified about 2800-fold. 3. It requires RNA, preferably of high molecular weight, and all four ribonucleoside triphosphates to incorporate 14C-labelled nucleoside triphosphate into an acid-insoluble, ribonuclease-sensitive product. 4. Both the stability and activity of the RNA polymerase are relatively insensitive to changes in potassium chloride or sodium chloride concentration, but incorporation is stimulated by both Mg2+ and Mn2+. 5. The molecular weight of the enzyme is about 17000–18000.


2002 ◽  
Vol 68 (8) ◽  
pp. 3965-3968 ◽  
Author(s):  
Patricia A. Shields ◽  
Samuel R. Farrah

ABSTRACT Viruses were characterized by their adsorption to DEAE-Sepharose or by their elution from octyl-Sepharose by using buffered solutions of sodium chloride with different ionic strengths. Viruses whose adsorption to DEAE-Sepharose was reduced most rapidly by an increase in the sodium chloride concentration were considered to have the weakest electrostatic interactions with the solids; these viruses included MS2, E1, and φX174. Viruses whose adsorption to DEAE-Sepharose was reduced least rapidly were considered to have the strongest electrostatic interactions with the column; these viruses included P1, T4, T2, and E5. All of the viruses studied adsorbed to octyl-Sepharose in the presence of 4 M NaCl. Viruses that were eluted most rapidly following a decrease in the concentration of NaCl were considered to have the weakest hydrophobic interactions with the column; these viruses included φX174, CB4, and E1. Viruses that were eluted least rapidly from the columns after the NaCl concentration was decreased were considered to have the strongest hydrophobic interactions with the column; these viruses included f2, MS2, and E5.


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.


1994 ◽  
Vol 51 (21) ◽  
pp. 2701-2704
Author(s):  
F. Pinguet ◽  
P. Martel ◽  
P. Rouanet ◽  
M. Fabbro ◽  
C. Astre

2013 ◽  
Vol 3 (1) ◽  
pp. 87 ◽  
Author(s):  
Quirino Dawa ◽  
Yufei Hua ◽  
Moses Vernonxious Madalitso Chamba ◽  
Kingsley George Masamba ◽  
Caimeng Zhang

<p>Understanding how foaming properties of proteins are affected by factors such as pH, salt concentration and temperature is essential in predicting their performance and utilisation. In this study, the effects of pH and salt concentration were studied on the foaming properties of pumpkin seed protein isolate (PSPI) and PSPI- xanthan (XG)/Arabic (GA) gum blends. The foaming properties of the PSPI-GA/XG blends were also compared with egg white. Foam stability (FS) was significantly affected by pH with PSPI: GA (25:4) and PSPI: XG (25:1) having a significantly higher stability at pH 2 with the lowest foam stability at pH 4. Sodium chloride (0.2-1.0 M) did not significantly affect foaming properties although PSPI: GA (25:4) had the highest FC (89.33 ± 3.24%) and FS (76.83 ± 1.53 min) at 0.2 M sodium chloride concentration. The foaming capacity (FC) of PSPI: GA (25:4) blend (128.00 ± 0.91%) was significantly higher (<em>p </em><em>&lt; </em>0<em>.</em>05) than that of egg white (74.00 ± 1.33%) but its FS was significantly lower. It was further revealed that the FC of egg white (74.00 ± 1.33%) was comparable to the PSPI:XG (25:1) blend (74.00 ± 1.46%) but the FS for egg white (480.00 ± 2.67 min) was significantly higher (<em>p </em><em>&lt; </em>0<em>.</em>05) than the FS (116.21 ± 0.86 min) of PSPI:XG (25:1). The foaming properties of PSPI and PSPI-xanthan (XG)/Arabic (GA) blends were significantly affected by pH. Optimum foaming properties, PSPI:XG (25:1) and PSPI:GA (25:4) were observed at pH 2 and heat treatment temperature of 80 ºC.</p>


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