COMPARAISON DE TOXICITÉ DE QUELQUES ÉLÉMENTS POUR BACILLUS THURINGIENSIS VAR. THURINGIENSIS BERL.

1967 ◽  
Vol 13 (1) ◽  
pp. 81-91 ◽  
Author(s):  
J. M. Perron ◽  
W. A. Smirnoff ◽  
L. Huot
Keyword(s):  
Cell Division ◽  
Bacillus Thuringiensis ◽  
Culture Medium ◽  
Toxic Effects ◽  
Clonal Structure ◽  
Structure Form ◽  
Cellular Lysis ◽  
Cobalt Copper

This study is concerned with the effects of aluminium, arsenic, boron, cobalt, copper, fluorine, iron, iodine, lithium, magnesium, molybdenum, and zinc on Bacillus thuringiensis var. thuringiensis Berliner. Addition of small quantities of the elements to the culture medium stimulated growth of the Bacillus. The effect was particularly marked during cell division, as revealed by an increase in area of the clones. The toxic effects of certain concentrations of the elements was also revealed during cell division, which, as indicated by the clonal area, was adversely affected by B, Cu, I, Mg, and Zn. F, Fe, Li, and Mo effected retardation of the cell division by as much as 12 to 48 hours. Al, As, Cu, and Mg both retarded and reduced cell division. By determining the relation between the effective limiting doses established, we were able to divide the elements into four groups. The toxicity of the elements was also revealed by its effects on the germination of the spores, clonal structure, form of the cells, time of sporulation, synthesis of the toxin-crystal, and cellular lysis.

EFFECTS OF PB2+ ON ROOT GROWTH, CELL DIVISION, AND NUCLEOLUS OF BRASSICA JUNCEA L.

1999 ◽  
Vol 47 (3) ◽  
pp. 153-156 ◽  
Author(s):  
Wusheng Jiang ◽  
Donghua Liu
Keyword(s):  
Cell Division ◽  
Root Growth ◽  
Brassica Juncea ◽  
Lead Nitrate ◽  
Inhibitory Effect ◽  
Toxic Effects ◽  
Root Tip ◽  
Anaphase Bridges ◽  
Tip Cells ◽  
Root Tip Cells

The effects of different concentrations (10−5-10−2M) of lead nitrate on root growth and nucleoli in root tip cells of Brassica juncea L. were investigated. The results showed that lead nitrate has a stimulatory effect on root growth at lower concentrations, and an inhibitory effect at higher concentrations. Pb has toxic effects on chromosomal morphology, including c-mitosis and anaphase bridges, and on nucleoli, causing some particulate silver-stained material scattered in the nuclei and inducing irregularly shaped nucleoli. Once the nucleolus was affected, the root growth almost or completely stopped.

Effect of strain and medium variation on mosquito toxin production by Bacillus thuringiensis var. israelensis

1982 ◽  
Vol 28 (9) ◽  
pp. 1089-1092 ◽  
Author(s):  
Robert A. Smith
Keyword(s):  
Bacillus Thuringiensis ◽  
Growth Medium ◽  
Shake Flask ◽  
Culture Medium ◽  
Toxin Production ◽  
Shake Flask Culture ◽  
Mosquito Larvae ◽  
Flask Culture ◽  
Strain Variation ◽  
Spore Count

The effect of strain variation and culture medium on production of toxin lethal to mosquito larvae by Bacillus thuringiensis var. israelensis serotype H-14 was investigated. Shake flask culture of B. thuringiensis H-14 strains showed varied ability to produce toxins lethal to mosquito larvae dependent upon the particular strain and growth medium used. Buffered media demonstrated no better mosquito toxicity than did unbuffered media that ranged in pH from 5.7 to 8.1 at harvest. Although toxin production is associated with sporulation, spore count was generally not proportional to toxin produced for those strains and media evaluated.

scholarly journals Induction by growth factors of polysaccharide synthases in bean cell suspension cultures

1983 ◽  
Vol 210 (2) ◽  
pp. 509-515 ◽  
Author(s):  
G P Bolwell ◽  
D H Northcote
Keyword(s):  
Cell Cycle ◽  
Growth Factors ◽  
Cell Division ◽  
Culture Medium ◽  
Actinomycin D ◽  
Cell Suspension Cultures ◽  
Suspension Cells ◽  
Membrane Bound ◽  
Total Membrane ◽  
Specific Mrna

Suspension cells of bean subcultured into medium that maintains the culture and stimulates cell division but not differentiation brings about an increase in arabinan synthase activity. Subculture into a medium that induces both cell division and xylogenesis brings about in addition an increase in xylan synthase. Both synthases are membrane-bound and are concerned with the formation of neutral pectin or hemicellulose of the cell wall respectively. During the rising phase of the induction of these activities in the appropriate culture medium, the increases in activities were inhibited by either actinomycin D (an inhibitor of transcription) or D-2-(4-methyl-2,6-dinitroanilino)-N-methylpropionamide (an inhibitor of translation). Thus the control for the induction of the enzyme activities involves transcription and possibly translation. Subculture of the cells brought about an increase, probably non-specific, in total membrane-bound translation, as indicated by increased amounts of bound polysomes and incorporation of [35S]methionine into membrane proteins. If the control of the appearance of specific mRNA molecules is partially effected by growth factors then these are probably operative during the period of the cell cycle that is stimulated by subculture and it is probably at this time that the growth factors act to bring about the changes necessary for differentiation.

Controls on Domoic Acid Production by the Diatom Nitzschia pungens f. multiseries in Culture: Nutrients and Irradïance

1991 ◽  
Vol 48 (7) ◽  
pp. 1136-1144 ◽  
Author(s):  
S. S. Bates ◽  
A. S. W. de Freitas ◽  
J. E. Milley ◽  
R. Pocklington ◽  
M. A. Quilliam ◽  
...  
Keyword(s):  
Cell Division ◽  
Stationary Phase ◽  
Exponential Growth ◽  
Domoic Acid ◽  
Culture Medium ◽  
Dark Period ◽  
Growth Conditions ◽  
Dark Cycle ◽  
Division Rate ◽  
Nitzschia Pungens

Nitzschia pungens f. multiseries (clone NPARL) was grown in nonaxenic batch culture under a range of growth conditions. Domoic acid (DA) was not detected during exponential growth, but production promptly started at a rate of approximately 1 pg DA∙cell−1∙d−1 at the onset of the stationary phase, in this case induced by silicate limitation. Cellular DA reached a maximum of 7 pg∙cell−1; thereafter, DA production continued at the same rate, with cellular levels remaining relatively constant due to concurrent release of DA into the culture medium. DA production ceased in the absence of nitrogen during the stationary phase, but resumed when nitrate was added back to the medium. Low irradiance slowed the division rate and consequently delayed the attainment of the stationary phase, but DA production rates were comparable with the control once stationary phase was reached. Cells during the dark period of a light–dark cycle, or placed into darkness, or in the presence of the photosynthetic inhibitor DCMU promptly ceased DA production. We conclude that at least three conditions are required for DA production by clone NPARL: cessation of cell division, availability of nitrogen during the stationary phase, and the presence of light. Growth in medium f/2 fulfils these requirements.

scholarly journals Induction, Growth Kinetics and Morpho-histological Characterization of Neem Callus

2018 ◽  
Vol 10 (6) ◽  
pp. 283
Author(s):  
Leila Albuquerque Resende de Oliveira ◽  
Annie Carolina Araújo de Oliveira ◽  
Caroline De Araújo Machado ◽  
Milena Nascimento Cardoso ◽  
Fernanda Vieira Santana ◽  
...  
Keyword(s):  
Cell Division ◽  
Azadirachta Indica ◽  
Culture Medium ◽  
Callus Formation ◽  
Nodal Segments ◽  
Insecticidal Action ◽  
Histological Characteristics ◽  
Light Brown Color

Azadirachta indica A. Juss, popularly known as neem, is a species native to India, belonging to family Meliaceae, considered the most important plant species with insecticidal action. The aim of this study was to evaluate the influence of growth regulators on induction and growth of neem callus and to observe their viability for embryogenesis through morpho-histological characteristics. In vitro germinated plants were used for excision of nodal explants. These segments were inoculated in Murashige and Skoog culture medium containing 1.0 mg/l 2,4-D (2,4-dichlorophenoxyacetic) combined with BAP (6-benzylaminopurine) at the following concentrations: 0.0, 0.5, 1.0 and 2.0 mg/l (T1, T2, T3 and T4 respectively), for callus induction. At 0 (mass of nodal segments without callus), 20, 40 and 60 days of culture, the percentage of callus formation was observed and the callus weight was measured for each treatment and at the end of the 60 days, consistency, color, and cell histology were evaluated. There was callus formation in all treatments tested. The highest induction of Azadirachta indica A. Juss callus is observed in the presence of 1.0 mg/l 2,4-D + 2.0 mg/l BAP, with callus showing light brown color, friable consistency and rounded cells with intense cell division, typical of cells with potential embryogenic capacity.

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