Bacillus thuringiensis parasporal crystal toxin: Dissociation into toxic low molecular weight peptides

1980 ◽  
Vol 95 (3) ◽  
pp. 1314-1320 ◽  
Author(s):  
P.G. Fast ◽  
W.G. Martin
Keyword(s):  
Molecular Weight ◽  
Bacillus Thuringiensis ◽  
Low Molecular Weight ◽  
Parasporal Crystal ◽  
Crystal Toxin

Alkaline extraction of toxin from spores of the mosquito pathogen, Bacillus sphaericus strain 1593

1983 ◽  
Vol 29 (2) ◽  
pp. 271-275 ◽  
Author(s):  
Elizabeth West Davidson
Keyword(s):  
Molecular Weight ◽  
Bacillus Thuringiensis ◽  
Bacillus Sphaericus ◽  
Alkaline Extraction ◽  
Toxic Activity ◽  
Crystal Toxin ◽  
Mosquito Pathogen

Toxin was extracted from spores of the mosquito pathogen Bacillus sphaericus strain 1593 using 0.05 M NaOH. The molecular weight of this toxin was 35 000–54 000. Toxic activity of this extract was resistant to a variety of enzymes including subtilisin, but was degraded by pronase. Antiserum produced to 1593 spore toxin neutralized spore toxin and cytoplasmic toxin activity, but did not react with Bacillus thuringiensis var. israelensis crystal toxin, nor did var. israelensis toxin antiserum react with B. sphaericus toxin. Crystallike parasporal inclusions accompanying the B. sphaericus 1593 spores were removed by NaOH extraction.

Inhibition of Bacillus thuringiensis proteases and their effects on crystal toxin proteins and cell-free translations

1988 ◽  
Vol 34 (6) ◽  
pp. 740-747 ◽  
Author(s):  
Margaret Bibilos ◽  
Robert E. Andrews Jr.
Keyword(s):  
Molecular Weight ◽  
Bacillus Thuringiensis ◽  
Proteolytic Activity ◽  
Exponential Phase ◽  
Late Exponential Phase ◽  
Stages Of Growth ◽  
Translational Activity ◽  
Low Levels ◽  
Crystal Toxin ◽  
Neutral Metal

Proteases produced during growth and sporulation of four strains of Bacillus thuringiensis were examined. Low levels of proteolytic activity were detected during the late exponential phase of growth in all four strains: two strains of B. thuringiensis subsp. kurstaki and one strain each of subsp. israelensis and berliner. In all strains, protease activities increased dramatically at the onset of sporulation. The principal proteases, both extra- and intra-cellular, were neutral, metal-loproteases. The pH optima and substrate specificities of proteases extracted from cells in various stages of growth and sporulation indicated that substantial diversity existed among the strains. Intracellular proteases from all four strains converted the 135 000 molecular weight protoxin of strain HD251, an isolate previously shown to have reduced intracellular proteolytic activity and which normally does not contain a protein of the lower molecular weight, to a 68 000 molecular weight toxin. Cell-free translational activity of extracts from strain HD251 were approximately fivefold more active than were equivalent extracts from strain LB1 presumably because of the reduced intracellular proteolytic activity of this strain.

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.

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

Venous thromboembolism in a general hospital. An update with low molecular weight heparin prophylaxis

VASA ◽  
2007 ◽  
Vol 36 (1) ◽  
pp. 17-22
Author(s):  
Schulz ◽  
Kesselring ◽  
Seeberger ◽  
Andresen
Keyword(s):  
Molecular Weight ◽  
Pulmonary Embolism ◽  
Venous Thromboembolism ◽  
Low Molecular Weight ◽  
Trauma Patients ◽  
Vte Prophylaxis ◽  
Vein Thrombosis ◽  
Patients At Risk ◽  
Hospital Stays ◽  
Event Rates

Background: Patients admitted to hospital for surgery or acute medical illnesses have a high risk for venous thromboembolism (VTE). Today’s widespread use of low molecular weight heparins (LMWH) for VTE prophylaxis is supposed to have reduced VTE rates substantially. However, data concerning the overall effectiveness of LMWH prophylaxis is sparse. Patients and methods: We prospectively studied all patients with symptomatic and objectively confirmed VTE seen in our hospital over a three year period. Event rates in different wards were analysed and compared. VTE prophylaxis with Enoxaparin was given to all patients at risk during their hospital stay. Results: A total of 50 464 inpatients were treated during the study period. 461 examinations were carried out for symptoms suggestive of VTE and yielded 89 positive results in 85 patients. Seventy eight patients were found to have deep vein thrombosis, 7 had pulmonary embolism, and 4 had both deep venous thrombosis and pulmonary embolism. The overall in hospital VTE event rate was 0.17%. The rate decreased during the study period from 0.22 in year one to 0,16 in year two and 0.13 % in year three. It ranged highest in neurologic and trauma patients (0.32%) and lowest (0.08%) in gynecology-obstetrics. Conclusions: With a simple and strictly applied regimen of prophylaxis with LMWH the overall rate of symptomatic VTE was very low in our hospitalized patients. Beside LMWH prophylaxis, shortening hospital stays and substantial improvements in surgical and anasthesia techniques achieved during the last decades probably play an essential role in decreasing VTE rates.

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