scholarly journals PHAGE FORMATION IN STAPHYLOCOCCUS MUSCAE CULTURES

1949 ◽  
Vol 32 (3) ◽  
pp. 301-311 ◽  
Author(s):  
Winston H. Price
Keyword(s):  
Active Substance ◽  
Synthetic Medium ◽  
Calf Thymus ◽  
Enzyme Formation ◽  
In Cells

1. A non-dialyzable fraction from fresh bakers' yeast stimulates the formation of S. muscae virus in cells in synthetic medium in the log phase of multiplication. 2. A similar fraction was not found in calf thymus, pancreas, or liver. 3. The active substance in this fraction has been partially purified. 4. This substance is taken up by the cells. In the absence of virus the added substance is metabolized to a form no longer available for virus formation. 5. A purified yeast fraction, which stimulates adaptive enzyme formation in yeast, has been found to stimulate virus formation in the S. muscae system. 6. The similarities between the yeast fraction that stimulates adaptive enzyme formation and the yeast fraction that stimulates virus formation are discussed.

scholarly journals Bacterial Oxidation of Arsenite II. The Activity of Washed Suspensions

1954 ◽  
Vol 7 (4) ◽  
pp. 479 ◽  
Author(s):  
AW Turner ◽  
JW Legge
Keyword(s):  
Synthetic Medium ◽  
Bacterial Oxidation ◽  
In Cells

Maximum arsenite-oxidizing activity of a pseudomonad (Ps. arsenoxydansquinque) isolated from "oxidized" arsenical cattle-dipping fluids was found in cells 3-4 days old, when cultivated in a synthetic medium containing arsenite. The system is adaptive, cells cultivated in the absence of arsenite showing no arsenite-oxidizing activity.

THE ROLE OF A PROTEASE IN SPORULATION OF PENICILLIUM JANTHINELLUM

1966 ◽  
Vol 44 (5) ◽  
pp. 579-584 ◽  
Author(s):  
A. Thangamani ◽  
T. Hofmann
Keyword(s):  
Acridine Orange ◽  
Synthetic Medium ◽  
Acid Protease ◽  
Logarithmic Phase ◽  
Penicillium Janthinellum ◽  
Indirect Connection ◽  
High Enzyme ◽  
Complete Synthetic Medium ◽  
Enzyme Formation

Although peptidase A, the trypsinogen-activating acid protease of Penicillium janthinellum, is formed during the post-logarithmic phase of growth and while the organism is actively sporulating, there is no direct correlation between the production of the enzyme and sporulation. The evidence for this is threefold: (a) in surface cultures acridine orange almost completely suppresses enzyme formation but reduces sporulation to a much smaller extent; (b) 6-ethyl-thiopurine decreases spore formation but stimulates the production of peptidase A; (c) transfer of mycelium in the log phase from a complete, synthetic medium to a medium lacking nitrate induces the formation of high enzyme levels without affecting the spore count.The possibility of an indirect connection between sporulation and peptidase production is not ruled out.

PROTEINASE BIOSYNTHESIS BY STREPTOCOCCUS LIQUEFACIENS: II. PURINE, PYRIMIDINE, AND VITAMIN REQUIREMENTS

1957 ◽  
Vol 3 (4) ◽  
pp. 553-558 ◽  
Author(s):  
R. E. Hartman ◽  
L. N. Zimmerman ◽  
R. Rabin
Keyword(s):  
Synthetic Medium ◽  
Inhibitory Effect ◽  
Enzyme Synthesis ◽  
Nitrogen Bases ◽  
Best Response ◽  
Straight Line ◽  
Amino Acid Requirements ◽  
Enzyme Formation ◽  
Vitamin Requirements ◽  
Initial Medium

Proteinase biosynthesis by Streptococcus liquefaciens, strain 31, may be obtained from an entirely synthetic medium. Adenine and uracil seem to satisfy best the purine and pyrimidine requirement while pyridoxal and riboflavin is the combination of vitamins that leads to maximal enzyme biosynthesis. Biotin and folic acid together, or thiamine, have an inhibitory effect on enzyme synthesis. The amino acid requirements for optimum activity are unaffected by the reduced number of vitamins and nitrogen bases present in the final medium as compared to the initial medium. A reduction in the number of vitamins (to pyridoxal and riboflavin), however, showed that only adenine and uracil gave the best response to the purine and pyrimidine demands for biosynthesis; prior to this, in the presence of a complete vitamin pool, several combinations of nitrogen bases yielded equal enzymatic activity. When proteinase synthesis is plotted against time, enzyme formation ceases at about 3 hours. The shape of the curve indicates a straight-line relationship after an initial lag period of 90 minutes.

A novel p-dimethylaminophenylether-based fluorescent probe for detecting native ONOO− in cells and zebrafish

The Analyst ◽  
2021 ◽  
Author(s):  
Wenlong Sheng ◽  
Kun Wang ◽  
Na Gao ◽  
Lizhen Wang ◽  
Rongchun Wang ◽  
...  
Keyword(s):  
Fluorescent Probe ◽  
Active Substance ◽  
Essential Role ◽  
Cell Homeostasis ◽  
Highly Active ◽  
Abnormal State ◽  
In Cells

Peroxynitrite (ONOO−), as a highly active substance, plays an essential role in maintaining cell homeostasis. It is crucial to monitor the level of ONOO− in normal and abnormal state of...

scholarly journals THE FATE OF INJECTED PARTICULATE ANTIGENS IN RELATION TO THE FORMATION OF ANTIBODIES

1946 ◽  
Vol 84 (2) ◽  
pp. 157-165 ◽  
Author(s):  
T. N. Harris ◽  
W. E. Ehrich
Keyword(s):  
Lymph Node ◽  
Active Substance ◽  
Regional Lymph Node ◽  
Lymphatic Tissue ◽  
Soluble Substance ◽  
Antigenic Material ◽  
Soluble Material ◽  
In Cells

Earlier studies have shown that the injection of antigenic material into the pad of the rabbit's foot is followed by the appearance of antibodies in the regional lymph node, in lymph coming from that node, and especially in the lymphocytes present in such efferent lymph. In the present work the fate of particulate antigenic material has been investigated during the period between its injection into the foot of the rabbit and the appearance of antibodies in the regional lymphatic tissue. It has been found that soluble substance of the same immunologic specificity as the antigenic material injected can be identified in extracts of the injected tissue and of the regional lymph node, and in the efferent lymph from that node. The concentration of this soluble material falls off slowly in the injected tissue in the course of the few days following the injection. It falls off quickly in the extract of the lymph node and in the lymph itself, and its disappearance is succeeded by the appearance of antibody. Evidence is presented that the immunologically active substance is derived from the injected antigenic material by a physiologic process, and this process is discussed as the means by which antigens, originally comprised in cells, are made available to the lymphocyte.

scholarly journals PHAGE FORMATION IN STAPHYLOCOCCUS MUSCAE CULTURES

1949 ◽  
Vol 32 (4) ◽  
pp. 481-488
Author(s):  
Winston H. Price
Keyword(s):  
Virus Particle ◽  
Synthetic Medium ◽  
Multiple Infection ◽  
Virus Release ◽  
Cellular Lysis ◽  
In Cells

1. In the synthetic medium of Fildes contaming hydrolyzed casein virus release is not correlated with observable cellular lysis under conditions of a very low multiple infection. 2. In cells with a high multiple infection, lysis occurs much sooner than in cells with a low multiple infection and virus release is correlated with cellular lysis. The experiments indicate that it is the virus particle itself which accelerates lysis under these conditions. 3. A non-dialyzable fraction has been isolated from yeast, the addition of which results in cellular lysis occurring at a sooner than usual interval and being correlated with virus release in cells having a very low multiple infection. 4. By varying the concentration of the yeast fraction, it is possible to lyse the cells at varying times under conditions of a low multiple infection.

Stimulierung von Kulturen embryonaler Rattenzellen durch Kälberserum / Stimulation of Embryonic Rat Cells in Culture by Calf Serum

1972 ◽  
Vol 27 (5) ◽  
pp. 562-566 ◽  
Author(s):  
Johanna Grimm ◽  
Werner Frank
Keyword(s):  
Synthetic Medium ◽  
Calf Serum ◽  
Lag Phase ◽  
Double Labelling ◽  
Serum Free Medium ◽  
Free Medium ◽  
Serum Free ◽  
Protein Binding Assay ◽  
Adenosine Phosphates ◽  
In Cells

Embryonic rat cells cultured in a synthetic medium are stopped in G1 phase if serum is omitted from the culture medium. On addition of calf serum these cells resume DNA synthesis after a lag phase of 15—20 hours. In the present paper the events concerning the metabolism of adenosine phosphates after stimulation by serum have been examined. The results are the following:1. The concentration of cAMP in cells which have been incubated for 24 hours in serum-free medium is 32 times higher than that in cells growing in medium containing 10 per cent calf serum; the accumulated cAMP is metabolized within 10 min after the addition of 10 per cent calf serum. This has been confirmed by a double labelling technique after preincubation with radioactive adenosine as well as by estimation of cAMP using a protein-binding assay.2. A cAMP-specific phosphodiesterase is activated shortly after stimulation; the enzyme activity in dialysed cell homogenates is increased within 30 min by a factor of 2.3. Cells incubated in serum-free and those in serum-containing medium have equal amounts of ATP. On addition of serum the ATP concentration in cells preincubated in serum-free medium decreases by 27%; the original level is restored 20—30 min later.

Heterogeneity of Size and Distribution of Intramembrane Particles in the Plasma Membrane of Yeast

1977 ◽  
Vol 35 ◽  
pp. 596-597
Author(s):  
E. Keyhani
Keyword(s):  
Plasma Membrane ◽  
Candida Utilis ◽  
Synthetic Medium ◽  
Freeze Fracture ◽  
Translational Diffusion ◽  
Yeast Cells ◽  
Distilled Water ◽  
Intramembrane Particles ◽  
The Matrix ◽  
Water Cell

The matrix of biological membranes consists of a lipid bilayer into which proteins or protein aggregates are intercalated. Freeze-fracture techni- ques permit these proteins, perhaps in association with lipids, to be visualized in the hydrophobic regions of the membrane. Thus, numerous intramembrane particles (IMP) have been found on the fracture faces of membranes from a wide variety of cells (1-3). A recognized property of IMP is their tendency to form aggregates in response to changes in experi- mental conditions (4,5), perhaps as a result of translational diffusion through the viscous plane of the membrane. The purpose of this communica- tion is to describe the distribution and size of IMP in the plasma membrane of yeast (Candida utilis).Yeast cells (ATCC 8205) were grown in synthetic medium (6), and then harvested after 16 hours of culture, and washed twice in distilled water. Cell pellets were suspended in growth medium supplemented with 30% glycerol and incubated for 30 minutes at 0°C, centrifuged, and prepared for freeze-fracture, as described earlier (2,3).

Cytoplasmic Tubules in Cells Infected with Laryngotracheitis Virus

1969 ◽  
Vol 27 ◽  
pp. 376-377
Author(s):  
A. M. Watrach
Keyword(s):  
Tissue Culture ◽  
Small Proportion ◽  
Chicken Embryo ◽  
Culture Cells ◽  
Tissue Culture Cells ◽  
Morphologic Characteristics ◽  
Infectious Laryngotracheitis ◽  
Laryngotracheitis Virus ◽  
In Cells

During a study of the development of infectious laryngotracheitis (LT) virus in tissue culture cells, unusual tubular formations were found in the cytoplasm of a small proportion of the affected cells. It is the purpose of this report to describe the morphologic characteristics of the tubules and to discuss their possible association with the development of virus.The source and maintenance of the strain of LT virus have been described. Prior to this study, the virus was passed several times in chicken embryo kidney (CEK) tissue culture cells.

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