Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 8 de 8
Filter
Add more filters










Database
Language
Publication year range
1.
Prikl Biokhim Mikrobiol ; 38(5): 540-7, 2002.
Article in Russian | MEDLINE | ID: mdl-12391756

ABSTRACT

Accumulation of Bacillus thuringiensis subsp. thuringiensis beta-exotoxin (BET) in the course of industrial fermentation (a stage in the production of the entomocidal biopreparation bitoxibacillin) has been studied. It has been demonstrated in model experiments that the decrease in the content of BET in the culture fluid is accounted for by the toxin interaction with an attendant product, the exogenous metabolite (EM). EM has been isolated from the culture fluid and characterized. EM causes alkalization of the medium, exerts entomocidal effects (in Musca domestica) and fails to form salts on treatment with BaCl2. The absorption spectrum of EM is similar to that of BET, showing a maximum at lambda = 259 nm. The light-absorbing chromophore is a pyrimidine or purine base. A method for quantitative determination of both exotoxins (BET and EM) in bacterial preparations has been developed.


Subject(s)
Bacillus thuringiensis/metabolism , Insecticides/metabolism , Animals , Diptera , Fermentation , Insecticides/pharmacology , Kinetics , Organic Chemicals , Pest Control, Biological
2.
Article in Russian | MEDLINE | ID: mdl-2354222

ABSTRACT

A method of quantitative determination of beta-exotoxin content in liquid and dry bioformulations has been developed. The method includes a thin-layer chromatography to isolate beta-exotoxin from accompanying nucleotides, the further desorption of a single beta-exotoxin spot by water and to carry out spectrophotometry at 259 and 330 nm. beta-exotoxin content in industrial formulations bitoxibacillin and turingin I has been determined. The results obtained correspond to the NMR 1H spectroscopy data within the experimental errors. The relative error is 1-2%. The method sensitivity of 0.05 mg/ml. beta-exotoxin content at biotechnological stages of bitoxibacillin production has been determined.


Subject(s)
Bacillus thuringiensis , Exotoxins/analysis , Insecticides/analysis , Chromatography, Thin Layer , Magnetic Resonance Spectroscopy , Molecular Weight , Organic Chemicals , Spectrophotometry, Ultraviolet
3.
Antibiot Khimioter ; 34(11): 841-6, 1989 Nov.
Article in Russian | MEDLINE | ID: mdl-2561254

ABSTRACT

New methods were developed and applied to quantitative determination of beta-exotoxin and antibiotic activity of delta-endotoxin with respect to Micrococcus spp. in bitoxibacillin (BTB) and the fermentation broths prepared under industrial conditions. The biosynthesis of beta-exotoxin in the period of its maximum accumulation during the fermentation was estimated. It was shown that the primary biological effect of BTB on insects consisted in the actions of beta-exotoxin and delta-endotoxin. Biological activity of each of the entomocidal components of the entomocidal components of BTB did not practically correlated with the number of viable spores. There was a correlation between the antibiotic activity of crystalline B. thuringiensis subsp. thuringiensis solutions and the insecticidal activity of the entomopathogenic preparations. Determination of beta-exotoxin and antibiotic activity of delta-endotoxin might be used as a complex procedure for testing the quality of BTB. The method for estimating antibiotic activity of the crystal solutions allowed one to assay the biological activity of other preparations based on Bacillus thuringiensis non-synthesizing beta-exotoxin.


Subject(s)
Bacterial Proteins , Bacterial Toxins , Endotoxins/pharmacology , Exotoxins/pharmacology , Insecta , Insecticides/pharmacology , Micrococcus/drug effects , Peptides/pharmacology , Animals , Anti-Bacterial Agents , Bacillus thuringiensis Toxins , Culture Media , Hemolysin Proteins , In Vitro Techniques , Insecticides/analysis , Organic Chemicals
4.
Article in Russian | MEDLINE | ID: mdl-2669979

ABSTRACT

The fluorescence spectra of Bacillus thuringiensis native cells at 340 nm induction have been investigated. The spectral curve has 440-445 and 510-515 nm maximums of fluorescence of pyridine nucleotides (PN) and flavoproteins (FP). The induction of PN and FP fluorescence under anaerobiosis resulted from bacterium breath has been found. The fluorescence induction is connected with the viability of cells. The amplitude of induced fluorescence is in a linear dependence on the number of vegetative cells in medium. The given experimental approaches may be used in a course of development of methods of continuous control over the physiological state change of microorganisms.


Subject(s)
Bacillus thuringiensis/physiology , Fluorescence , Anaerobiosis , Escherichia coli/physiology , Flavoproteins/metabolism , NAD/metabolism , Oxidation-Reduction , Oxygen/metabolism , Spectrometry, Fluorescence , Temperature
5.
Biofizika ; 21(2): 307-12, 1976.
Article in Russian | MEDLINE | ID: mdl-1268278

ABSTRACT

Migration energy between three forms of the precursor of chlorophyll and chlorophyllide are measured and calculated. Absorption coefficients, fluorescence yields of pigment forms and dimensions of native complexes (20-22 molecules) are calculated.


Subject(s)
Chlorophyll , Chlorophyll/analysis , Energy Transfer , Plants/analysis , Spectrometry, Fluorescence
SELECTION OF CITATIONS
SEARCH DETAIL
...