scholarly journals STUDIES ON THE ENZYMES OF PNEUMOCOCCUS

1920 ◽  
Vol 32 (5) ◽  
pp. 583-593 ◽  
Author(s):  
O. T. Avery ◽  
Glenn E. Cullen
Keyword(s):  
Living Cell ◽  
Living Cells ◽  
Active Enzyme ◽  
Hydrogen Ion ◽  
Ion Concentrations ◽  
Optimum Reaction ◽  
Secretory Products ◽  
Cell Disintegration

1. A method is described for the preparation of an active enzyme-containing solution of pneumococci, in which no living cells are present. These enzymes are capable of hydrolyzing sucrose, starch, and inulin. 2. The invertase and amylase of pneumococcus are active within the limits pH 5 to 8, with an optimum reaction of about pH 7. This reaction range corresponds closely with limiting hydrogen ion concentrations which define growth of the organism in the presence of carbohydrate. 3. These studies indicate that the enzymes described are not true secretory products of the living cell, but are of the nature of endoenzymes, since their activity can be demonstrated only when cell disintegration has occurred.

The Influence of Hydrogen-ion Concentration on Some Acid Resistant Bacteria

1938 ◽  
Vol 4a (3) ◽  
pp. 219-227
Author(s):  
Dennis W. Watson
Keyword(s):  
Living Cell ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Resistant Bacteria ◽  
Limited Growth ◽  
Genus Bacillus ◽  
Hydrogen Ion Concentration ◽  
Ion Concentrations ◽  
Bacillus Strains

Fifty-three strains of bacteria have been isolated from acidulated brine. They are classified into Bacillus, Micrococcus, Sarcina, and Lactobacillus. Of these the Bacillus strains failed to grow at hydrogen-ion concentrations more acid than pH 6.20, while the Micrococcus and Sarcina forms showed a greater tolerance, producing limited growth from pH 5.22 to 5.64. Other workers describing wider limits for the genus Bacillus failed to allow for the change produced in the weakly buffered environment by the living cell. The microaerophilic Lactobacilli grew at pH 3.52. These aciduric types are not actively proteolytic.

scholarly journals STUDIES ON ENZYME ACTION

1927 ◽  
Vol 10 (6) ◽  
pp. 845-851
Author(s):  
Helen Miller Noyes ◽  
I. Lorberblatt ◽  
K. George Falk
Keyword(s):  
Sodium Chloride ◽  
Active Enzyme ◽  
Hydrogen Ion ◽  
Chloride Solutions ◽  
Ion Concentrations ◽  
Enzyme Action ◽  
Sodium Chloride Solutions

The ester-hydrolyzing actions of trout extracts at different hydrogen ion concentrations were studied. It was pointed out that the behavior was similar to that found with various tissue and tumor materials and that similar relations hold. Glycerol solutions extracted somewhat larger amounts of active enzyme material from trout than did water and sodium chloride solutions, although the differences were not large. Evidence was presented for the existence of a so called "coenzyme."

scholarly journals THE PERMEABILITY OF LIVING CELLS TO DYES AS AFFECTED BY HYDROGEN ION CONCENTRATION

1922 ◽  
Vol 5 (2) ◽  
pp. 223-224 ◽  
Author(s):  
Marian Irwin
Keyword(s):  
Living Cell ◽  
Quantitative Method ◽  
Living Cells ◽  
Low Ph ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Hydrogen Ion Concentration ◽  
Rate Of Penetration ◽  
Cresyl Blue ◽  
Ph Values

1. An accurate quantitative method of measuring the penetration of dye into the living cell is described. 2. Cresyl blue is unable to penetrate rapidly unless the pH outside the cell is decidedly greater than that inside. The rate of penetration increases with increasing pH. 3. Around pH 9 penetration of the dye is rapid while the reverse is true of exosmosis. At low pH values (5.9) exosmosis is rapid and penetration is very slow.

scholarly journals Nanoarchitectonics on living cells

RSC Advances ◽  
2021 ◽  
Vol 11 (31) ◽  
pp. 18898-18914
Author(s):  
Katsuhiko Ariga ◽  
Rawil Fakhrullin
Keyword(s):  
Living Cell ◽  
Living Cells ◽  
Material Surfaces ◽  
As If

We can introduce functional structures with various components on a living cell as if architectures were constructed on material surfaces.

scholarly journals The acidity of muscle during maintained contraction

1922 ◽  
Vol 93 (654) ◽  
pp. 406-410
Keyword(s):  
Manganese Dioxide ◽  
Hydrogen Ion ◽  
Ion Concentrations

In 1913, I described a method for recording changes in hydrogen-ion concentrations in tissues, by means of a manganese dioxide electrode in combination with a calomel electrode (1). By this method it was shown that the acidity of muscle probably increased at the same time as, or slightly before, the tension increased, and that the acidity decreased as the muscle relaxed (2). In a paper, which appeared as this note was being prepared for publication, Ritchie states that he has been unable to detect a variation in acidity by the use of manganese dioxide electrodes. I am inclined to think that his failure is due to the injury to the muscles on insertion of wires into its substance. In my own experiments the wires rest on the surface of the muscle.

Graphene-Semiconductor Tubular Needles for Operations of Living Cells

2010 ◽  
Vol 5 (1) ◽  
pp. 90-96
Author(s):  
Aleksandr V. Kopylov ◽  
Viktor Ya. Prinz
Keyword(s):  
High Precision ◽  
Biological Material ◽  
Living Cell ◽  
Cylindrical Shells ◽  
Living Cells ◽  
The Novel ◽  
Graphene Structures

The possibility of application of the novel class of tubular needles for piercing cells and injecting biological material inside the cell is considered. Stability calculations of tubular (multiwall) needles were made. Calculations were made for the needles with walls formed from hybrid graphene-semiconductor or graphene structures and spires shaped as trapeziform open cylindrical shells. The possibility of mass fabrication of such needles and chips for AFM significantly broadens the range of available operations on the surface and inside the living cell and opens prospects of effective high-precision manipulations with individual cells.

Computational Foundations of the Anticipatory Artificial Autopoietic Cellular Automata

2021 ◽  
pp. 289-307
Author(s):  
Daniel M. Dubois ◽  
Stig C. Holmberg
Keyword(s):  
Artificial Intelligence ◽  
Cellular Automata ◽  
Living Cell ◽  
Artificial Life ◽  
Initial Conditions ◽  
Living Cells ◽  
Asymmetric Membrane

A survey of the Varela automata of autopoiesis is presented. The computation of the Varela program, with initial conditions given by a living cell, is not able to self-maintain the membrane of the living cell. In this chapter, the concept of anticipatory artificial autopoiesis (AAA) is introduced. In this chapter, the authors present a new algorithm of the anticipatory artificial autopoiesis, which extend the Varela automata. The main enhancement consists in defining an asymmetric membrane of the artificial lining cell. The simulations show the anticipatory generation of artificial living cells starting with any initial conditions. The new concept of anticipatory artificial autopoiesis is related to artificial life (Alife) and artificial intelligence (AI). This is a breakthrough in the computational foundation of autopoiesis.

Sign in / Sign up

Export Citation Format

Share Document