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101.
Bacillus thuringiensis subsp.israelensis andB. sphaericus strains 2362 and 1593 were grown in media based on defatted mustard-seed meal (MSM). The meal contains 40% (w/w) protein, with glutamic acid and arginine as the major amino acids. The toxic potencies of the final bacterial powders towardsCulex pipens quinquefasciatus Say, compared with those of the respective international reference standards, were 46% forB. thuringiensis subsp.israelensis, 62% forB. sphaericus 2362 and 88% forB. sphaericus 1593 when 2% (w/v) MSM was used for growth. With 4% (w/v) MSM,B. thuringiensis subsp.israelensis grew better but had undetectable larvicidal activity, whereas theB. sphaericus strains not only grew better but gave a higher degree of sporulation and toxicity. The potencies ofB. sphaericus in medium with 4% MSM were comparable with those of international reference standards.The authors are with the Department of Life Sciences, University of Bombay, Bombay 400 098, India. 相似文献
102.
J. A. Ampofo 《Biocontrol Science and Technology》1995,5(4):417-424
Locally available raw materials were used as fermentation media for the preparation of an effective bacterial insecticide of Bacillus sphaericus in Ghana. The choice of materials for media production was based on their availability, their cost and how well they supported growth and sporulation of the bacterium. The materials used were anchovy (Engraulis encrasicolus), spent grain from breweries, bambara beans (Vigna subterranea), sprout maize (Zea mays) and B. sphaericus strain IAB 881. The larvicidal activities of each final whole culture of the insecticides prepared were evaluated against third and fourth instar larvae of the mosquito species Culex quinquefasciatus. The levels of larvicidal activity exhibited by preparations using the raw materials were similar to those where the bacterium was cultured in a synthetic medium, with median lethal concentrations ranging from 0.30 10- 5 to 0.68 10-6. Cell counts were in the range 11 108 - 36 108 colony-forming units ml-1, and spore counts were between 29 107 and 61 107 ml-1. 相似文献
103.
P. K. Lee J. A. Buswell K. Shinagawa 《World journal of microbiology & biotechnology》1995,11(6):696-698
Eleven of 16 samples of rice on sale in rice shops and supermarkets in Hong Kong contained Bacillus cereus. Although B. cereus counts did not exceed 100 bacteria/g in most of the positive samples, a sample of Thai red rice and a poor quality rice originating from China contained between 300 to 1000 cells/g and 104 to 2×105 cells/g, respectively. Nine strains produced an enterotoxin responsible for the diarrhoeal-type B. cereus food poisoning and seven of these strains also produced a haemolysin (haemolysin BL), a dermonecrotic vascular permeability factor which may be a virulence determinant in diarrhoeal illness caused by this bacterium.P.K. Lee and J.A. Buswell are with the Department of Biology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong; K. Shinagawa is with the Department of Veterinary Medicine, Iwate University, Iwate, Japan. 相似文献
104.
Ravendra Pal Singh 《Journal of biosciences》1984,6(2):203-212
Rapidly metabolizable compounds such as glucose or glycerol were not utilized byBacillus megaterium in the absence of manganese when grown in the supplemented nutrient broth medium. Under these conditions, growth ceased at
low cell titre, 3-phosphoglyceric acid accumulated inside the cells and normal sporulation process was arrested. Addition
of manganese to the medium caused disappearance of 3-phosphoglyceric acid, growth resumed and normal sporulation was observed.
Synthesis of 3-phosphoglyceric acid occurred only in the mother cell compartments and it was transported for accumulation
inside the forespores ofBacillus megaterium when grown in supplemented nutrient broth medium. Incubation of forespores in the presence of glucose or glycerol had no
effect on 3-phosphoglyceric acid synthesis/accumulation, but it was completely utilized when forespores were incubated with
manganese plus ionophore (X 537A). No other metal(s) could substitute for manganese suggesting that manganese plays crucial
role in 3-phosphoglyceric acid metabolism 相似文献
105.
Ilkka Helander Kirsi Saukkonen Elias Hakalehto Martti Vaara 《FEMS microbiology letters》1984,24(1):39-42
Abstract A procedure is described in which the protein crystals produced by Bacillus thuringiensis var. israelensis were solubilized in 50 mM NaOH with 10 mM EDTA at pH 11.7. This solubilization procedure gave protein gel profiles identical with those for intact crystals while maintaining full biological activity in the form of erythrocyte lysis capability. Crystals with and without protease activity were equally toxic to Aedes aegypti larvae. 相似文献
106.
Surowitz Kenneth G. Titus Jeffrey A. Pfister Robert M. 《Archives of microbiology》1984,140(2-3):107-112
The effects of cadmium on the growth and respiration of two strains of Bacillus subtilis are compared to the accumulation of Cd by viable and cyanide-killed cells, protoplasts and cell fractions of the strains. Growth and respiration of strain 1A1 were significantly inhibited at 10g Cd2+/ml while the growth and respiration of strain 1A1R, a selected mutant of 1A1, were only slightly affected. Similarly, 1A1R protoplasts were more resistant to Cd than were 1A1 protoplasts. The differential resistance of the strains correlates with the accumulation of Cd by the two strains, with 1A1 accumulating approximately 10 times the level of Cd after a 4 h exposure to 1 g Cd2+/ml. The distributions of Cd throughout the cells, however, were similar between strains. Based on the accumulation of Cd by cyanide-killed protoplasts, uptake of Cd by 1A1 appears to be an active process, while for 1A1R, Cd accumulation is independent of protoplast viability.Non-standard abbreviations SMM
Subtilis Minimal Medium
- AAS
Atomic Absorption Spectrophotometry
- TSA
Trypticase Soy Agar
- PCA
Plate Count Agar
- INT
2-p-iodophenyl-3-p-nitrophenyl-5-phenyl-2H tetrazolium chloride
- dd H2O
double distilled demineralized water
- OD
Optical Density 相似文献
107.
The composition of the amino acid pool during spherulation was determined. It changes in size and in composition, the concentration of each amino acid behaving individually. The first response to the onset of spherulation either by starvation or osmotic shock (0.5 M mannitol) always is a decrease of the pool's size, which during further starvation expands for a short period and then decreases again. During development induces by mannitol in the presence of external amino acids, the pool size increases continuously after the initial depletion.As shown by radioactive labeling, amino acids were actively released from the plasmodium into a medium containing amino acids, but retained by the microplasmodia in an amino acid-free medium. The kinetics of the uptake of radioactive amino acids from the medium is biphasic, indicating the existence of multiple pools. Even after a labeling period of 8 h the amino acid pool is not yet in equilibrium with the medium. The possibility of a compartimentation of the pool was confirmed by density labeling of two different enzymes.Whereas the turnover of total protein is only very low during growth, it is rather high in spherulating microplasmodia. At least 70% of the originally existing protein is degraded during this development, while, simultaneously, at least 50% of the protein present after 24 h starvation is newly synthesized during that period. 相似文献
108.
Hydrophobic protein (H protein) was isolated from membrane fractions of Bacillus subtilis and constituted into artificial membrane vesicles with lipid of B. substilis. Glutamate was accumulated into the vesicle when a Na+ gradient across the membrane was imposed. The maximum effect of Na+ on the transport was achieved at a concentration of about 40 mM, while the apparent Km for Na+ was approximately 8 mM. On the other hand, Km for glutamate in the presence of 50 mM Na+ was about 8 μM. Increasing the concentration of Na+ resulted in a decrease in Km for glutamate, maximum velocity was not affected. The transport was sensitive to monensin (Na+ ionophore).Glutamate was also accumulated when pH gradient (interior alkaline) across the membrane was imposed or a membrane potential was induced with K+-diffusion potential. The pH gradient-driven glutamate transport was sensitive to carbonylcyanide m-chlorophenylhydrazone and the apparent Km for glutamate was approximately 25 μM.These results indicate that two kinds of glutamate transport system were present in H protein: one is Na+ dependent and the other is H+ dependent. 相似文献
109.
High concentration of L-cystine (0.25%) when present in a glucose-mineral salt medium inhibited sporulation-specific events
like protease production, calcium uptake and dipicolinic acid synthesis inBacillus thuringiensis var.thuringiensis. In addition, the enzymes of the Krebs cycle from aconitase onwards were completely inhibited by a high concentration of cystine.
At a low concentration of cystine (0.05%), none of the above mentioned macromolecular changes were affected. Lipid synthesis
monitored by [1,214 C]-acetate incorporation into lipid as well as into whole cells was completely inhibited. 相似文献
110.
The effect of the addition of different concentratons of cystine and cysteine on sporulation and parasporal crystal formation
inBacillus thuringiensis var.thuringiensis was studied. The effect was well pronounced when the cystine/cysteine additions were made after the stationary phase. Heat
stable spores and crystals were formed when the culture was provided with a low concentration of cystine/cysteine (0.05 per
cent w/v). At a moderate concentration of cystine or cysteine (0.15%), only heat labile spores were formed without the production
of the crystal. When the cystine/cysteine concentration was high (0.25%), spore and crystal formation were completely inhibited.
Partial reversal of inhibition of sporulation was brought about by sodium sulphate or Zinc sulphate and lead, copper, cadmium
or cobalt acetate at 0.2 mM or at 0.2% of sodium or potassium pyruvate, citrate, cisaconitate, oxalosuccinate, ∞ -keto-glutarate,
succinate, fumarate, malate, or oxalacetate. Glutamate (0.2%) overcame the inhibitory effect of cystine/cysteine completely.
The structural changes observed using phase contrast microscopy were dependent upon the concentration of cystine/cysteine. 相似文献