Adaptive response of Haloferax mediterranei to low concentrations of NaCl (< 20%) in the growth medium

1997 ◽  
Vol 168 (1) ◽  
pp. 68-71 ◽  
Author(s):  
S. E. D'Souza ◽  
Wijaya Altekar ◽  
S. F. D'Souza
Keyword(s):  
Growth Medium ◽  
Adaptive Response ◽  
Haloferax Mediterranei ◽  
Low Concentrations

Effects of Halides on Plasmid-Mediated Silver Resistance in Escherichia coli

1998 ◽  
Vol 64 (12) ◽  
pp. 5042-5045 ◽  
Author(s):  
Amit Gupta ◽  
Maria Maynes ◽  
Simon Silver
Keyword(s):  
Escherichia Coli ◽  
Growth Medium ◽  
Silver Sulfadiazine ◽  
Resistance Plasmid ◽  
Low Concentrations ◽  
Resistant Strains ◽  
High Concentrations

ABSTRACT Silver resistance of sensitive Escherichia coli J53 and resistance plasmid-containing J53(pMG101) was affected by halides in the growth medium. The effects of halides on Ag+ resistance were measured with AgNO3 and silver sulfadiazine, both on agar and in liquid. Low concentrations of chloride made the differences in MICs between sensitive and resistant strains larger. High concentrations of halides increased the sensitivities of both strains to Ag+.

The effect of fatty acids on the metabolism of lactic acid streptococci: II. Resistance of a variant of Streptococcus cremoris strain C 13

1964 ◽  
Vol 31 (1) ◽  
pp. 91-94 ◽  
Author(s):  
R. F. Anders ◽  
G. R. Jago
Keyword(s):  
Fatty Acids ◽  
Lactic Acid ◽  
Oleic Acid ◽  
Growth Medium ◽  
Streptococcus Cremoris ◽  
Low Concentrations ◽  
High Concentrations

SummaryIt was previously found that low concentrations of oleic acid in the growth medium inhibited the growth of Streptococcus cremoris strain C 13. However, a variant of this strain has now been isolated which is capable of growth in relatively high concentrations of oleic acid. This was achieved by the extended incubation of inocula of strain C 13 in milk containing various concentrations of oleic acid.

scholarly journals Distribution of TiO2 Nanoparticles in Acidic and Alkaline Soil and Their Accumulation by Aspergillus niger

Agronomy ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1833
Author(s):  
Martin Šebesta ◽  
Lucia Nemček ◽  
Martin Urík ◽  
Marek Kolenčík ◽  
Marek Bujdoš ◽  
...  
Keyword(s):  
Aspergillus Niger ◽  
Growth Medium ◽  
Inorganic Nanoparticles ◽  
Alkaline Soil ◽  
Soil Environment ◽  
Low Concentrations ◽  
Soil Solutions ◽  
Particulate Form ◽  
Ph Conditions ◽  
Plant Growth Stimulant

The nanoparticles of TiO2 (TiO2 NP) have been used as a plant-growth stimulant or catalyst in pesticide formulas. However, due to high resistance of TiO2 NP to abiotic weathering, dissolved Ti is unlikely to act as an active compound in these preparations. Even if soil is acidic, TiO2 NP do not dissolve easily and preferably remain as undissolved particles. The low dissolution rates of inorganic nanoparticles in the soil environment make Ti in TiO2 NP largely unavailable for plants and soil microorganisms. To characterize the behavior of TiO2 NP in soil under different pH conditions, we analyzed TiO2 NP-size distribution in two soil materials, an alkaline and acidic one. We also cultivated Aspergillus niger, a fungus ubiquitously found in soils, in the growth medium spiked with TiO2 NP to assess accumulation of the nanoparticles in fungus. In soil suspensions, the dissolved Ti was present in low concentrations (up to 0.010 mg L−1). Most of the TiO2 NP remained in particulate form or appeared as aggregates sized 100–450 nm. In experiment on Ti accumulation by A. niger, TiO2 NP either settled down to the bottom of the flask with growth medium or were actually accumulated by the fungus; about 7.5% of TiO2 NP were accumulated in fungal mycelia. Most of the TiO2 NP remain in particulate form in soil solutions, regardless of soil pH. Filamentous fungus A. niger has the ability to accumulate bioavailable TiO2 NP, which hints at the possibility that some soil fungi can affect spatial distribution of this type of nanoparticles in soils.

scholarly journals Growth-Dependent Stable Carbon Isotope Fractionation by Basidiomycete Fungi: δ13C Pattern and Physiological Process

2002 ◽  
Vol 68 (10) ◽  
pp. 4956-4964 ◽  
Author(s):  
Matthew R. Henn ◽  
Gerd Gleixner ◽  
Ignacio H. Chapela
Keyword(s):  
Growth Medium ◽  
Fungal Biomass ◽  
Growth Stage ◽  
Stable Carbon Isotope ◽  
Axenic Culture ◽  
Growth Stages ◽  
Second Phase ◽  
C Isotopes ◽  
Low Concentrations ◽  
The Impact

ABSTRACT We grew 11 basidiomycetes in axenic culture to characterize their physiological capacities to fractionate stable C isotopes. Generally, δ13C values of the fungal biomass were (i) enriched in 13C relative to the growth medium, (ii) variable among the isolates, and (iii) dependent on the growth rate and growth stage of the fungi. We found a multiphasic dynamic of fractionation for Cryptoporus volvatus and Marasmius androsaceus during various growth stages. The first phase, P1, corresponded to the exponential growth stage and was characterized by an increasing enrichment in 13C content of the fungal biomass relative to the growth medium ranging between 4.6 and 6.9‰. The second phase, P2, exhibited a continual depletion in 13C of the fungal biomass, with the δ13C values of the fungal biomass asymptotically returning to the δ13C value of the growth medium at inoculation. The expression of the various fractionation phases was dependent on the amount of low-concentration micronutrients and growth factors added to the growth medium. The onset of P2 occurred at reduced concentrations of these elements. All of the sugars in the growth medium (sucrose, maltose, and glucose) were utilized for growth, indicating that the observed fractionation was not an artifact derived from the preferential use of 13C-rich maltose, which was found at low concentrations in the growth medium. In this study, we establish a framework with which to explore the impact of physiological fractionations by fungal interfaces on natural distributions of stable C isotopes.

scholarly journals Effects of Rate and Repeat Application of Flurprimidol on the Growth of Photinia × fraseri and Ilex crenata ‘Compacta’

1988 ◽  
Vol 6 (4) ◽  
pp. 114-118
Author(s):  
Adolph J. Laiche
Keyword(s):  
Growth Medium ◽  
Shoot Growth ◽  
Foliar Spray ◽  
Growing Season ◽  
Plant Size ◽  
Foliar Sprays ◽  
Landscape Plants ◽  
Low Concentrations ◽  
Leaf Distortion ◽  
Test Plants

Flurprimidol, α-(1-Methylethyl)-α-[4-(trifluoromethoxy)phenyl]-5-pyrimidine-methanol, was applied to three month plants of Photinia × fraseri in 5.6 L (6 qt) containers and Ilex crenata ‘Compacta’ in 2.8 L (3 qt) containers as foliar sprays at 0, 33, 66, 132, 264, 528, 1056, 2112, 4224, and 8448 ppnl. Growth-medium drench applications with flurprimidol were applied at 0, 2, 4, 8, 16, 32, 64, 128, 256, and 512 ppm solution, 0.5 L (17 oz) per 5.6 L (6 qt) container to Photinia. The initial foliar spray treatments and the growth medium drench treatments were applied on July 14, 1983. All test plants were planted in soil on December 9, 1983. Foliar spray treatments were repeated on July 19, 1985. Flurprimidol at low concentrations as a spray and drench substantially reduced plant size with little or no phytotoxicity. Duration of growth suppression increased as rate increased. Flurprimidol at low rates reduced growth for the remainder of the growing season in which it was applied. At higher rates growth was also reduced in the following growing season. Minor leaf distortion of smaller leaves was obtained at low rates and leaf distortion appeared to increase slightly at higher rates. Shoot growth after the effects of flurprimidol were no longer apparent appeared normal. Results indicate that flurprimidol alone and in conjunction with pruning can be helpful in maintaining woody landscape plants to a desirable size.

scholarly journals Reactive Carbonyls Induce TOR- and Carbohydrate-Dependent Hormetic Response in Yeast

2020 ◽  
Vol 2020 ◽  
pp. 1-6 ◽  
Author(s):  
Halyna Semchyshyn
Keyword(s):  
Adaptive Response ◽  
Double Mutant ◽  
Carbonyl Stress ◽  
High Toxicity ◽  
Reactive Carbonyl Species ◽  
Hormetic Effect ◽  
Low Concentrations ◽  
Highly Sensitive ◽  
Genes Encoding ◽  
Hormetic Response

The induction of the beneficial and detrimental effects by reactive carbonyl species in yeast has been investigated. In this study, we have presented evidence that glyoxal and methylglyoxal at low concentrations were able to induce a hormetic adaptive response in glucose-grown but not fructose-grown yeast. The hormetic effect was also TOR-dependent. The mutation in genes encoding either TOR1 or TOR2 protein makes yeast highly sensitive to both α-dicarbonyls studied. Simultaneous disruption of TOR1 and TOR2 resulted in higher yeast sensitivity to the α-dicarbonyls as compared to parental cells, but double mutant survived better under carbonyl stress than its single mutant counterparts. The data obtained are consistent with the previous works which reported high toxicity of the α-dicarbonyls and extend them with the report on the beneficial TOR-dependent hormetic effect of glyoxal and methylglyoxal.

scholarly journals Analysis of benzotriazole influence on some morphological and physiological characteristics of Allium fistulosum

2019 ◽  
Vol 8 (1) ◽  
pp. 105-109
Author(s):  
Ekaterina Sergeevna Selezneva
Keyword(s):  
Adaptive Response ◽  
Isopropyl Alcohol ◽  
Objective Response ◽  
Allium Fistulosum ◽  
Anthropogenic Pressure ◽  
Toxic Dose ◽  
Model Experiments ◽  
Adaptive Capabilities ◽  
Low Concentrations ◽  
Test Objects

The increase in anthropogenic pressure has led to the need for model experiments to assess the ability of organisms to adapt to xenobiotics. The study of negative effects is usually carried out in laboratories using animals as test objects, while it is more interesting to study tolerance and adaptive capabilities in plant organisms, because, unlike animals, they are not able to leave an area uncomfortable for existence. In order to obtain an objective response in experiments, it is necessary to choose test objects related to species that are ubiquitous in ecosystems, and xenobiotics that are widely used and able to enter the environment. Allium fistulosum L. was used in model experiments and was affected by benzotriazole to study the possibility of developing an adaptive response in plants to anthropogenic pollutants. Plants were preadapted to a toxic dose of benzotriazole at a concentration of 0,1 mg/ml, by exposure to alcohol solutions of benzotriazole at a concentration of 0,0001 mg/ml or 0,001 mg/ml, and the time of preliminary exposure varied from 1 day to 4 days, then test objects germinated in a solution of high concentration. There were three controls, where the seeds were germinated for five days in all three used concentrations of benzotriazole, as well as in a solvent, which was 0,5% isopropyl alcohol. The possibility of adaptive response was assessed using two morphophysiological indicators, these were the germination of seeds and the average root length on the fifth day of the experiment. Experiments have shown that a solution of benzotriazole at a concentration of 0,1 mg/ml inhibits seeds germination and roots growth compared with the control (germination in 0,5% isopropyl alcohol), while at a concentration of 0,0001 mg/ml it stimulates. Exposure to low concentrations reliably creates a preadaptation to the toxic dose, but the responses significantly differ in effectiveness depending on the duration of preadaptation and the concentration of the substance. The greatest effect on the toxic effect of benzotriazole is created by preadaptation in low concentrations over 3 days. Possible preadaptation mechanisms are discussed.

scholarly journals Polyamine and ornithine metabolism during the germination of conidia of Aspergillus nidulans

1976 ◽  
Vol 158 (2) ◽  
pp. 235-241 ◽  
Author(s):  
L Stevens ◽  
I M McKinnon ◽  
M Winther
Keyword(s):  
Aspergillus Nidulans ◽  
Ornithine Decarboxylase ◽  
Growth Medium ◽  
Germ Tube ◽  
Decarboxylase Activity ◽  
Aminotransferase Activity ◽  
Adenosylmethionine Decarboxylase ◽  
Ornithine Decarboxylase Activity ◽  
Low Concentrations ◽  
Enzyme Changes

1. The activities of ornithine decarboxylase, S-adenosylmethionine decarboxylase and ornithine-2-oxoglutarate aminotransferase were studied during the first 24 h of conidial germination in Aspergillus nidulans. 2. Increases (over 100-fold) in the activities of ornithine decarboxylase and S-adenosylmethionine decarboxylase occurred during the emergence of the germ-tube and before the doubling of DNA and this was followed by a sharp fall in the activities of both enzymes by 16h. 3. The increase in ornithine decarboxylase could be largely suppressed if 0.6 mM-putrescine was added to the growth medium. 4. Low concentrations of cycloheximide, which delayed germination by 2h, caused a corresponding delay in the changes in ornithine decarboxylase activity. 5. Ornithine-2-oxoglutarate aminotransferase activity increased steadily during the first 24h of germination. 6. Ornithine or arginine in the growth medium induced higher activity of ornithine-2-oxoglutarate aminotransferase, but did not affect ornithine decarboxylase activity. 7. The significance of these enzyme changes during germination is discussed.

Bactericidal photoproducts in medium containing riboflavin plus aromatic compounds and MnCl2

1983 ◽  
Vol 29 (6) ◽  
pp. 670-675 ◽  
Author(s):  
Cesar A. Chelala ◽  
Paul Margolin
Keyword(s):  
Hydrogen Peroxide ◽  
Acetic Acid ◽  
Visible Light ◽  
Salmonella Typhimurium ◽  
Propionic Acid ◽  
Growth Medium ◽  
Aromatic Compounds ◽  
Aminobenzoic Acid ◽  
Low Concentrations ◽  
Indole 3 Acetic Acid

Exposure to visible light of growth medium containing riboflavin and indole at low concentrations created photoproducts highly toxic to Salmonella typhimurium and other bacteria. No toxicity was detected in the dark or when either of these two components was present singly. Other aromatic compounds (serotonin, indole-3-acetic acid, indole-3-propionic acid, tryptophan, tyrosine, phenylalanine, and p-aminobenzoic acid) tested in place of indole produced various degrees of toxicity. The presence of MnCl2 significantly enhanced the toxicity. Addition of catalase eliminated the toxicity, indicating an important role for hydrogen peroxide.

The isolation and cultivation of protoplasts from cell suspensions of a pantothenate-requiring auxotroph of Datura

1985 ◽  
Vol 63 (4) ◽  
pp. 779-783 ◽  
Author(s):  
M. Mii ◽  
S. Seeni ◽  
L. C. Fowke ◽  
J. King
Keyword(s):  
Liquid Medium ◽  
Cell Line ◽  
Growth Medium ◽  
Physiological State ◽  
Cell Suspensions ◽  
Dichlorophenoxyacetic Acid ◽  
Physiological Changes ◽  
Wild Type ◽  
Low Concentrations ◽  
2,4 Dichlorophenoxyacetic Acid

Protoplasts isolated from Datura cells requiring pantothenate for growth (Pn1 cell line) failed to divide in a medium containing 0.5 M mannitol if the cells from which they were derived had been subcultured in liquid medium more than four times. Division could be reinduced either by increasing the concentration of 2,4-dichlorophenoxyacetic acid (2,4-D) in the growth medium from 1 to 2.5–5 mg/L, by adding low concentrations (0.01 – 1 mg/L) of benzyladenine to a growth medium containing 1 mg/L of 2,4-D, or by diluting the 0.5 M mannitol in the medium to 0.2 M immediately after isolation of the protoplasts. Thus, the physiological state of Pn1 cells seems to change significantly after only a few passages in liquid medium. These changes can be prevented or partially reversed by manipulating the medium in which the cells and protoplasts are cultured. Similar physiological changes did not occur in the case of cultured wild-type (Ph4), adenine-requiring (Ad1), or isoleucine–valine-requiring (I–VI) cells of Datura.

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