PRODUCTION OF GIBBERELLIN-LIKE SUBSTANCES BY BACTERIA AND ACTINOMYCETES

1965 ◽  
Vol 11 (4) ◽  
pp. 733-741 ◽  
Author(s):  
H. Katznelson ◽  
Shirley E. Cole
Keyword(s):  
Gibberellic Acid ◽  
Root Surface ◽  
Bacillus Polymyxa ◽  
Microbial Synthesis ◽  
Agrobacterium Radiobacter ◽  
Bacterial Cultures ◽  
Related Substances ◽  
Cultural Conditions ◽  
Culture Filtrates ◽  
Maximum Benefit

The production of gibberellin-like substances by bacteria and actinomycetes was investigated. Most of the bacterial cultures tested produced a gibberellic acid-like substance (A3) in amounts varying from 1 to 14 μg/liter. The production of a gibberellin-A9-like compound was much more limited, 6 out of 15 cultures yielding small amounts. Six out of 11 actinomycetes showed evidence of A3 synthesis; two produced A9. Antigibberellin substances co-chromatographing with A3 were detected in culture filtrates of Bacillus polymyxa and two actionmycetes. Cultural conditions and concentration of the ingredients of the medium influenced gibberellin synthesis by Agrobacterium radiobacter. Production of these substances was not growth linked and none was detected in stationary cultures. Microbial synthesis of the gibberellins was demonstrated also by means of assays with the dwarf maize mutants d1, d2, and d5.As added to soil was rapidly inactivated and it was postulated that the plant could derive maximum benefit from microbial synthesis of gibberellins and related substances only at the root surface—the rhizoplane.

Activités physiologiques de l'ochracine, synthétisée par Septoria nodorum, sur la croissance de plantules de riz et sur la synthèse ‘de novo’ des alpha-amylases par les couches à aleurone du caryopse de blé. Interaction avec l'acide gibbérellique

1979 ◽  
Vol 57 (6) ◽  
pp. 561-567 ◽  
Author(s):  
G. Touraud ◽  
J. F. Bousquet
Keyword(s):  
Synergistic Effect ◽  
Gibberellic Acid ◽  
De Novo ◽  
Pathogenic Fungus ◽  
Septoria Nodorum ◽  
De Novo Synthesis ◽  
Rice Seedlings ◽  
Culture Filtrates ◽  
Increased Sensitivity ◽  
Tissue Permeability

Ochracine was isolated from culture filtrates of Septoria nodorum Berk. (Berk.), a pathogenic fungus of wheat. At concentrations ranging from 25 μg/mL it inhibited the growth of wheat and rice seedlings and the 'de novo' synthesis of α-amylases by the aleurone layers of wheat. These effects were not reversed by increased concentrations of gibberellic acid.Between 2.5 and 10 μg/mL, ochracine exhibited a synergistic effect with exogenous gibberellic acid on the same physiological phenomena. For these last concentrations, the results suggest an increased sensitivity of rice seedlings and wheat aleurone layers to exogenous gibberellic acid as a result of changes in tissue permeability.

scholarly journals Biodegradation of Atrazine by Agrobacterium radiobacter J14a and Use of This Strain in Bioremediation of Contaminated Soil

1998 ◽  
Vol 64 (9) ◽  
pp. 3368-3375 ◽  
Author(s):  
J. K. Struthers ◽  
K. Jayachandran ◽  
T. B. Moorman
Keyword(s):  
Indigenous Population ◽  
Carbon Sources ◽  
Nitrogen Sources ◽  
Agrobacterium Radiobacter ◽  
Carbon And Nitrogen ◽  
Cultural Conditions ◽  
Herbicide Atrazine ◽  
Lag Times ◽  
Chemical Distribution ◽  
Atrazine Degradation

ABSTRACT We examined the ability of a soil bacterium, Agrobacterium radiobacter J14a, to degrade the herbicide atrazine under a variety of cultural conditions, and we used this bacterium to increase the biodegradation of atrazine in soils from agricultural chemical distribution sites. J14a cells grown in nitrogen-free medium with citrate and sucrose as carbon sources mineralized 94% of 50 μg of [14C-U-ring]atrazine ml−1 in 72 h with a concurrent increase in the population size from 7.9 × 105 to 5.0 × 107 cells ml−1. Under these conditions cells mineralized the [ethyl-14C]atrazine and incorporated approximately 30% of the 14C into the J14a biomass. Cells grown in medium without additional carbon and nitrogen sources degraded atrazine, but the cell numbers did not increase. Metabolites produced by J14a during atrazine degradation include hydroxyatrazine, deethylatrazine, and deethyl-hydroxyatrazine. The addition of 105 J14a cells g−1 into soil with a low indigenous population of atrazine degraders treated with 50 and 200 μg of atrazine g−1soil resulted in two to five times higher mineralization than in the noninoculated soil. Sucrose addition did not result in significantly faster mineralization rates or shorten degradation lag times. However, J14a introduction (105 cells g−1) into another soil with a larger indigenous atrazine-mineralizing population reduced the atrazine degradation lag times below those in noninoculated treatments but did not generally increase total atrazine mineralization.

MICROBIAL GROWTH FACTORS IN RELATION TO RESISTANCE OF FLAX VARIETIES TO FUSARIUM WILT

1961 ◽  
Vol 39 (1) ◽  
pp. 7-19 ◽  
Author(s):  
A. G. Lochhead ◽  
F. D. Cook
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Fusarium Oxysporum ◽  
Microbial Growth ◽  
Root Surface ◽  
Susceptible Variety ◽  
Resistant Variety ◽  
Pathogenic Potential ◽  
Related Substances ◽  
Growth Promoting

A comparison was made of growth factor requirements and growth factor synthesizing capacity of bacteria from the root surface and from the seeds of flax varieties resistant and susceptible, respectively, to wilt caused by Fusarium oxysporum f. lini. The percentage of bacteria from both root and seed which required growth-promoting substances was greater with the resistant ('Bison') than with the susceptible ('Novelty') variety. On the other hand bacteria capable of synthesizing growth factors were proportionately more abundant with the susceptible variety. The findings indicate a more pronounced rhizosphere effect exerted by the susceptible than by the resistant variety, and point to circumstances that favor a greater accumulation (or 'turnover') of vitamins and related substances at the root surface of susceptible plants.Two strains of Fusarium oxysporum f. lini capable of inducing wilt required no vitamins for growth; thiamine had a depressing effect. Both strains were able to synthesize various growth factors, though in different degree. Culture filtrates of bacteria from roots of the two varieties of flax showed no difference in their effect on growth of Fusarium; however, bacteria from the resistant variety showed somewhat greater ability to depress Fusarium than those from the susceptible. Though the findings do not constitute evidence of any relationship between differences in growth factor relationships to pathogenic potential of Fusarium, they suggest the value of considering growth-promoting substances in studies of the effect of nutrition on the activity of soil-borne pathogens.

scholarly journals Microbial synthesis and evaluation of bactericidal properties of cadmium sulfide nanoparticles

2021 ◽  
Author(s):  
O. A. Zhuravliova ◽  
T. A. Voeikova ◽  
V. S. Kuligin ◽  
V. G. Debabov
Keyword(s):  
Stationary Phase ◽  
Cadmium Sulfide ◽  
Scientific Data ◽  
Biocidal Activity ◽  
Microbial Synthesis ◽  
Gram Positive ◽  
Gram Negative ◽  
Bacterial Cultures ◽  
Bactericidal Properties ◽  
K 12

Introduction. The productivity of microbial synthesis of stable nanoparticles is determined by the growth stage of the populations of bacterial cultures used to obtain nanostructures. The study of the biocidal activity of biogenic nanoparticles of cadmium sulfide (NPsCdS), comparable in properties with nanomaterials obtained by physicochemical methods, is promising.The aim of this work was to evaluate the effect of the cell growth phase of the bacterial strains Bacillus subtilis 168 and Shewanella oneidensis MR-1 on the efficiency of biosynthesis of NPsCdS and to study their bactericidal properties against a number of gram-positive and gram-negative strains of microorganisms.Material and methods. Nanoparticles were obtained by introducing Na2 S and CdCl2 salts to a final concentration of 2 mM : 2 mM in liquid bacterial cultures with cells in different phases of growth. The efficiency of NPsCdS biosynthesis was evaluated by the optical density of aqueous nanoparticles solutions. The bactericidal properties of NPsCdS were determined by the diameter of zone of inhibition growth of gram-positive bacteria B. subtilis 168, B. amyloliquefaciens, Streptococcus salivarius, Rhodococcus rhodochrous and gram-negative S. oneidensis MR-1, Escherichia coli K-12, Pseudomonas putida.Results. It was found that the use of cells in the stationary phase of growth (18–24 hours) contributes to obtaining the maximum amount of NPsCdS corresponding to concentrations of 1.0–1.2 mg/ml. The high antimicrobial activity of NPsCdS was shown against gram-positive microorganisms, among gram-negative bacteria, P. putida strain showed insignificant sensitivity.Discussion. The experimental results expand scientific data about the effect of the phase of bacterial growth cycle on biosynthesis of nanoparticles. The stationary phase of growth of B. subtilis 168, S. oneidensis MR-1 is optimal for obtaining of NPsCdS. For the first time, the cytotoxicity of NPsCdS/Shewanella against bacteria of various taxonomic groups was demonstrated. Conclusion. An effective method for obtaining extracellular NPsCdS using bacteria B. subtilis 168, S. oneidensis MR-1 in the stationary phase of growth has been developed. The biocidal activity of biogenic NPsCdS was shown, which allows to consider them as a new class of antimicrobial agents. 

Factors influencing the rooting of Gisela 5 (Prunus cerasus × Prunus canescens) cherry rootstock hardwood cuttings

2006 ◽  
Vol 46 (12) ◽  
pp. 1633 ◽  
Author(s):  
E. Exadaktylou ◽  
T. Thomidis ◽  
C. Tsipouridis ◽  
B. Grout
Keyword(s):  
Gibberellic Acid ◽  
Starch Content ◽  
Prunus Cerasus ◽  
Agrobacterium Radiobacter ◽  
Factors Influencing ◽  
Rooting Of Cuttings ◽  
Double Splitting ◽  
Bottom Heat ◽  
Collection Date ◽  
Gisela 5

In this study, the effect of double splitting, cooling in pre-storage, collection date, indole-3-butyric acid (IBA) dipping of shoot tip and base, gibberellic acid (GA3), Agrobacterium radiobacter and A. rhizogenes on the callusing and rooting of Gisela 5 cherry rootstock hardwood cuttings was investigated. Double splitting and bacteria did not affect the callusing and rooting of cuttings. The callusing and rooting of cuttings kept at 0–3°C for 15 days or more were significantly reduced. The callusing and rooting percentages were highest when only the base of cuttings was treated with 1000 mg/L IBA solution. The rooting percentage of cuttings increased when 10–20 mg/L GA3 was applied the same day cuttings were placed on a bottom heat bench. The results showed that the best periods to collect Gisela 5 hardwood cuttings were the later half of November and early March. No correlation between the collection date and starch content, and the starch content and the callusing and rooting of Gisela 5 hardwood cuttings was found.

scholarly journals METHEMOGLOBIN FORMATION BY STERILE CULTURE FILTRATES OF PNEUMOCOCCUS

1924 ◽  
Vol 40 (2) ◽  
pp. 269-279 ◽  
Author(s):  
Hugh J. Morgan ◽  
James M. Neill
Keyword(s):  
Hydrogen Peroxide ◽  
Bacterial Cell ◽  
Sterile Culture ◽  
Oxidizing Agents ◽  
Cultural Conditions ◽  
Culture Filtrates ◽  
Methemoglobin Formation

1. Sterile filtrates of aerobic cultures of pneumococcus which contain hydrogen peroxide are capable of converting catalase-free solutions of crystalline oxyhemoglobin into methemoglobin. This action is dependent upon the hydrogen peroxide in the filtrates and occurs only in the absence of blood catalase. 2. In catalase-containing solutions of hemoglobin from laked corpuscles, the actual methemoglobin-forming system of Pneumococcus involves a labile constituent of the bacterial cell. This intracellular substance is itself susceptible to oxidizing agents and may be rendered inactive, if exposed to peroxide or similar substances previous to its introduction into oxyhemoglobin solutions. The activity of this function in the case of sterile filtrates of pneumococcus cultures depends, therefore, upon the liberation of cell constituents into the medium and upon the protection of these cellular substances from the oxidizing agents which are formed when pneumococcus cultures are freely exposed to air. When these cultural conditions are fulfilled sterile culture filtrates of Pneumococcus convert oxyhemoglobin into methemoglobin independent of the presence of blood catalase.

RTS,S/AS01, a vaccine targeting pre-erythrocytic stages of Plasmodium falciparum

2017 ◽  
Vol 1 (6) ◽  
pp. 533-537
Author(s):  
Lorenz von Seidlein ◽  
Borimas Hanboonkunupakarn ◽  
Podjanee Jittmala ◽  
Sasithon Pukrittayakamee
Keyword(s):  
Protective Efficacy ◽  
Age Groups ◽  
Sub Saharan Africa ◽  
Phase Iii ◽  
European Medicines Agency ◽  
Older Children ◽  
Pivotal Phase ◽  
Malaria Epidemiology ◽  
Maximum Benefit ◽  
Sub Saharan

RTS,S/AS01 is the most advanced vaccine to prevent malaria. It is safe and moderately effective. A large pivotal phase III trial in over 15 000 young children in sub-Saharan Africa completed in 2014 showed that the vaccine could protect around one-third of children (aged 5–17 months) and one-fourth of infants (aged 6–12 weeks) from uncomplicated falciparum malaria. The European Medicines Agency approved licensing and programmatic roll-out of the RTSS vaccine in malaria endemic countries in sub-Saharan Africa. WHO is planning further studies in a large Malaria Vaccine Implementation Programme, in more than 400 000 young African children. With the changing malaria epidemiology in Africa resulting in older children at risk, alternative modes of employment are under evaluation, for example the use of RTS,S/AS01 in older children as part of seasonal malaria prophylaxis. Another strategy is combining mass drug administrations with mass vaccine campaigns for all age groups in regional malaria elimination campaigns. A phase II trial is ongoing to evaluate the safety and immunogenicity of the RTSS in combination with antimalarial drugs in Thailand. Such novel approaches aim to extract the maximum benefit from the well-documented, short-lasting protective efficacy of RTS,S/AS01.

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