Recherches sur la lysogénie chez Bacillus thuringiensis et B. cereus

1978 ◽  
Vol 24 (7) ◽  
pp. 818-826 ◽  
Author(s):  
H.-W. Ackermann ◽  
W. A. Smirnoff
Keyword(s):  
Molecular Weight ◽  
Bacillus Thuringiensis ◽  
Mitomycin C ◽  
Ultraviolet Light ◽  
Low Molecular Weight ◽  
Apparent Correlation ◽  
Phage Sensitivity

Forty-eight strains of Bacillus thuringiensis and 12 strains of B. cereus were treated with ultraviolet light and mitomycin C. The former agent was the more effective inducer. Bacillus thuringiensis produces at least seven different phage particles with long, non-contractile tails. The frequencies of lysogeny and polylysogeny are 83 and 25% respectively. Morphologically defective phages occur in 25% of strains, whereas five of them produce low molecular-weight bacteriocins. One strain of B. cereus harbors "killer-particles." There is no apparent correlation between the presence of phage-like particles, phage sensitivity, and serotypes, biotypes, or the origin of B. thuringiensis strains.

scholarly journals A family of low molecular-weight, organic catalysts for reductive C–C bond formation

2015 ◽  
Vol 51 (73) ◽  
pp. 13902-13905 ◽  
Author(s):  
Saad Shaaban ◽  
Anaïs Jolit ◽  
Desislava Petkova ◽  
Nuno Maulide
Keyword(s):  
Molecular Weight ◽  
Ultraviolet Light ◽  
Bond Formation ◽  
Diazonium Salts ◽  
Low Molecular Weight ◽  
Organic Catalysts

Using only small amounts of a hydrazine catalyst, the coupling of diazonium salts to a variety of reactive partners has been achieved, without the requirement for either metal adjuvants or irradiation with visible or ultraviolet light.

scholarly journals PROPERTIES OF THE CAUSATIVE AGENT OF A CHICKEN TUMOR

1940 ◽  
Vol 71 (5) ◽  
pp. 619-633 ◽  
Author(s):  
Albert Claude ◽  
Alexandre Rothen
Keyword(s):  
Molecular Weight ◽  
Absorption Spectrum ◽  
Nucleic Acid ◽  
Ultraviolet Light ◽  
High Speed ◽  
Active Principle ◽  
Low Molecular Weight ◽  
Differential Centrifugation ◽  
Complete Inactivation ◽  
Tumor Agent

1. The tumor-producing fraction, isolated from Chicken Tumor I by means of differential centrifugation at high speed, has been investigated as regards its power to absorb ultraviolet light. A characteristic absorption spectrum was found, with a maximum at λ2575. The absorbing power of the material in that region was largely due to the presence of nucleic acid, or of a closely related compound. 2. Inactivation of the purified tumor fraction with ultraviolet light depressed the absorbing power of the material, especially in the region of 2600–2500Å. These changes were those which nucleic acid would present under the same conditions. 3. Inactivation of the tumor agent with acid or alkali was accompanied by decomposition of the tumor nucleoprotein and passage of free nucleic acid into solution. 4. Partial or complete inactivation of the tumor agent by heat, at 50° or 65deg;C., was attended by liberation of nucleic acid of low molecular weight. 5. The parallelism between tumor-producing activity and the integrity of the tumor ribonucleoprotein suggests that the nucleoprotein may be an essential part of the active principle.

scholarly journals THE NATURE OF COLICIN K FROM PROTEUS MIRABILIS

1970 ◽  
Vol 131 (5) ◽  
pp. 1016-1038 ◽  
Author(s):  
Margeris A. Jesaitis
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Mitomycin C ◽  
Growth Medium ◽  
Proteus Mirabilis ◽  
Satellite Dna ◽  
Biological Properties ◽  
Low Molecular Weight ◽  
E Coli ◽  
K Factor

The colicinogenic factor K has been transferred from E. coli K 235 to Proteus mirabilis. The DNA of the colicinogenic Proteus has been shown to contain a small amount of a satellite DNA which presumably harbors the Col K factor. In the presence of mitomycin C the colicinogenic Proteus secretes colicin K into the growth medium. The bacteriocin has been purified by chromatography and obtained as an immunologically homogeneous substance unconjugated with other antigens of the Proteus bacillus. Proteus colicin K is a protein of relatively low molecular weight. It contains all of the usual amino acids except cysteine and is free of lipids and polysaccharides. The bacteriocin can be separated by electrofocusing into two major components. The latter have the same biological properties but differ in their specific electrical charges.

A high-performance oil-free backing pump for electron microscopes

1978 ◽  
Vol 36 (1) ◽  
pp. 110-111
Author(s):  
G.K.W. Balkau ◽  
E. Bez ◽  
J.L. Farrant
Keyword(s):  
Molecular Weight ◽  
Electron Microscope ◽  
Hot Spots ◽  
High Performance ◽  
Carbonaceous Material ◽  
Contamination Rate ◽  
Low Molecular Weight ◽  
Principal Source ◽  
Rotary Pumps ◽  
Electron Microscopes

The earliest account of the contamination of electron microscope specimens by the deposition of carbonaceous material during electron irradiation was published in 1947 by Watson who was then working in Canada. It was soon established that this carbonaceous material is formed from organic vapours, and it is now recognized that the principal source is the oil-sealed rotary pumps which provide the backing vacuum. It has been shown that the organic vapours consist of low molecular weight fragments of oil molecules which have been degraded at hot spots produced by friction between the vanes and the surfaces on which they slide. As satisfactory oil-free pumps are unavailable, it is standard electron microscope practice to reduce the partial pressure of organic vapours in the microscope in the vicinity of the specimen by using liquid-nitrogen cooled anti-contamination devices. Traps of this type are sufficient to reduce the contamination rate to about 0.1 Å per min, which is tolerable for many investigations.

Low-molecular-weight heparin in the prevention and treatment of thromboembolic disorders

1998 ◽  
Vol 1 (5) ◽  
pp. 166-174 ◽  
Author(s):  
Evelyn R Hermes De Santis ◽  
Betsy S Laumeister ◽  
Vidhu Bansal ◽  
Vandana Kataria ◽  
Preeti Loomba ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Low Molecular Weight ◽  
Prevention And Treatment
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