scholarly journals Lower formulation pH does not enhance bentazone uptake into plant foliage

2002 ◽  
Vol 55 ◽  
pp. 163-167 ◽  
Author(s):  
Z.Q. Liu
Keyword(s):  
Plant Cells ◽  
Sinapis Alba ◽  
Weak Acid ◽  
Foliar Uptake ◽  
Plant Foliage ◽  
Wheat Leaves ◽  
Spray Formulation ◽  
Acid Herbicides

Lower pH generally favours the diffusion of weak acid compounds in vitro into plant cells Such a rule may not be applicable to the uptake of formulated weak acid herbicides applied to plant foliage in vivo In this study the effect of spray formulation pH (5 7 and 9) on the foliar uptake of a weak acid herbicide bentazone which is used as a formulated salt was investigated using three plant species mustard (Sinapis alba) wheat (Triticum aestivum) and bean (Vicia faba) Greater uptake of the herbicide occurred at pH 9 and pH 7 than at pH 5 on mustard and wheat leaves Uptake of bentazone into bean was slow (< 20 after 24 h) regardless of carrier pH However in the presence of a surfactant faster uptake was achieved with higher pH The results are discussed in relation to the lipophilicity and the solubility of weak acid chemicals as influenced by pH

Bentazone uptake into plant foliage as influenced by surfactants and carrier pH

2004 ◽  
Vol 55 (9) ◽  
pp. 967 ◽  
Author(s):  
Z. Q. Liu
Keyword(s):  
Sodium Salt ◽  
Current Knowledge ◽  
Sinapis Alba ◽  
Weak Acid ◽  
Foliar Uptake ◽  
Promoting Effect ◽  
Enhancing Effect ◽  
Low Concentration ◽  
Plant Foliage ◽  
Linear Alcohols

The influence of surfactants and carrier pH on the foliar uptake of bentazone, a representative weak acid herbicide, was studied using bean (Vicia faba) and mustard (Sinapis alba) plants. The promoting effect of surfactants on bentazone uptake varied with surfactant hydrophobe structure, ethylene oxide (EO) content, and surfactant and bentazone concentrations. Among the 5 hydrophobe moieties tested, the efficiency order was C13 /C15 linear alcohols > C10 linear alcohol > C16 /C18 linear alcohols > nonylphenol > octylphenol. For C13 /C15 linear alcohol surfactants of differing EO content, the enhancing effect on bentazone uptake was 5 EO > 10 EO > 14 EO. All surfactants improved uptake more when bentazone was applied at low concentration. The effect of carrier pH (5, 7, and 9) on the uptake of bentazone, applied both as unformulated acid and as a sodium salt, was also investigated in this work. Lower carrier pH did not provide greater uptake for bentazone sodium salt and was only beneficial for the uptake of bentazone acid applied at very low concentration. The results are discussed in relation to the current knowledge on pesticide uptake as influenced by surfactants and the change in lipophilicity and solubility of weak acid chemicals at different pH.

scholarly journals Reaction of wheat cultivars and differential lines to Puccinia triticina races in detached leaves

2014 ◽  
Vol 40 (4) ◽  
pp. 353-357 ◽  
Author(s):  
Camila Turra ◽  
Erlei M. Reis ◽  
Amarilis L. Barcellos
Keyword(s):  
Puccinia Triticina ◽  
Petri Dish ◽  
Wheat Cultivars ◽  
Wheat Leaf Rust ◽  
Detached Leaf ◽  
Wheat Leaf ◽  
Detached Leaves ◽  
Wheat Leaves

The method of preserving detached wheat leaves in Petri dish was used for the inoculation and development of the fungus Puccinia triticina, the causal agent of wheat leaf rust. The reaction of 26 wheat cultivars was compared by using seedlings cultivated in pots (in vivo) and detached leaves (in vitro) inoculated with four physiological races of the pathogen. After inoculation, the material was kept in a growth chamber for 15 days. The reaction was evaluated on the 15th day after inoculation. Results for each race in the evaluated genotypes confirmed the efficiency of the detached leaf method in assessing the reaction of wheat cultivars.

scholarly journals Effects of organic acids on the gut ecosystem and on the performance of broiler chickens

2017 ◽  
Vol 65 (4) ◽  
pp. 289 ◽  
Author(s):  
M. ANDREOPOULOU (Μ. ΑΝΔΡΕΟΠΟΥΛΟΥ) ◽  
V. TSIOURIS (Β. ΤΣΙΟΥΡΗΣ) ◽  
I. GEORGOPOULOU (Ι. ΓΕΩΡΓΟΠΟΥΛΟΥ)
Keyword(s):  
Antibacterial Activity ◽  
Organic Acids ◽  
Broiler Chickens ◽  
Weak Acid ◽  
Growth Enhancement ◽  
Growth Promoters ◽  
Salmonella Spp ◽  
Mineral Absorption

Organic acids are studied as candidate alternatives to antibiotic growth promoters. Their action is related to the pH reduction of the intestinal digesta, affecting the gut ecosystem in numerous ways. Intestinal microbiota can be altered as a result of the remarkable antibacterial activity of organic acids and the growth enhancement of non-pathogenic beneficial microorganisms, due to exclusive competition. Antibacterial activity has been widely reported for many poultry pathogens, such as Salmonella spp., Escherichia coli, Clostridium perfringens, Campylobacter spp., both in vitro and in vivo. However, it seems to depend on many factors concerning the weak acid used and the gut ecosystem. Apart from the microbiota, diet supplementation of organic acids has trophic effects on the intestinal mucosa, modifying the morphologic characteristics of intestinal villi and crypts and maintaining epithelial integrity. Furthermore, as found recently, organic acids have anti-inflammatory and immunostimulating properties. Diet acidification increases gastric proteolysis and the utilization of proteins and amino acids, affects pancreatic secretions and mineral absorption. There are also reports for an effect on appetite and palatability of the feed. All these properties attributed to organic acids have either a direct or indirect effect on the performance and health, even though the results presented for poultry lack consistency. Nonetheless, the benefits of organic acids can have practical application in the control of clinical and subclinical conditions, but more research is needed to study these perspectives.

Conservation of targeting but divergence in function and quality control of peroxisomal ABC transporters: an analysis using cross-kingdom expression

2011 ◽  
Vol 436 (3) ◽  
pp. 547-557 ◽  
Author(s):  
Xuebin Zhang ◽  
Carine De Marcos Lousa ◽  
Nellie Schutte-Lensink ◽  
Rob Ofman ◽  
Ronald J. Wanders ◽  
...  
Keyword(s):  
Quality Control ◽  
Arabidopsis Thaliana ◽  
Abc Transporters ◽  
Plant Cells ◽  
Related Protein ◽  
Peroxisomal Membrane ◽  
And Function ◽  
Native Host

ABC (ATP-binding cassette) subfamily D transporters are found in all eukaryotic kingdoms and are known to play essential roles in mammals and plants; however, their number, organization and physiological contexts differ. Via cross-kingdom expression experiments, we have explored the conservation of targeting, protein stability and function between mammalian and plant ABCD transporters. When expressed in tobacco epidermal cells, the mammalian ABCD proteins ALDP (adrenoleukodystrophy protein), ALDR (adrenoleukodystrophy-related protein) and PMP70 (70 kDa peroxisomal membrane protein) targeted faithfully to peroxisomes and P70R (PMP70-related protein) targeted to the ER (endoplasmic reticulum), as in the native host. The Arabidopsis thaliana peroxin AtPex19_1 interacted with human peroxisomal ABC transporters both in vivo and in vitro, providing an explanation for the fidelity of targeting. The fate of X-linked adrenoleukodystrophy disease-related mutants differed between fibroblasts and plant cells. In fibroblasts, levels of ALDP in some ‘protein-absent’ mutants were increased by low-temperature culture, in some cases restoring function. In contrast, all mutant ALDP proteins examined were stable and correctly targeted in plant cells, regardless of their fate in fibroblasts. ALDR complemented the seed germination defect of the Arabidopsis cts-1 mutant which lacks the peroxisomal ABCD transporter CTS (Comatose), but neither ALDR nor ALDP was able to rescue the defect in fatty acid β-oxidation in establishing seedlings. Taken together, our results indicate that the mechanism for trafficking of peroxisomal membrane proteins is shared between plants and mammals, but suggest differences in the sensing and turnover of mutant ABC transporter proteins and differences in substrate specificity and/or function.

scholarly journals One and Two-Step In Vitro-In Vivo Correlations Based on USP IV Dynamic Dissolution Applied to Four Sodium Montelukast Products

Pharmaceutics ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 690
Author(s):  
Mercedes Prieto-Escolar ◽  
Juan J. Torrado ◽  
Covadonga Álvarez ◽  
Alejandro Ruiz-Picazo ◽  
Marta Simón-Vázquez ◽  
...  
Keyword(s):  
Test Procedure ◽  
Sodium Dodecyl ◽  
Weak Acid ◽  
Added Value ◽  
Time Scaling ◽  
One Step ◽  
Flow Through ◽  
Low Solubility

Montelukast is a weak acid drug characterized by its low solubility in the range of pH 1.2 to 4.5, which may lead to dissolution-limited absorption. The aim of this paper is to develop an in vivo predictive dissolution method for montelukast and to check its performance by establishing a level-A in vitro-in vivo correlation (IVIVC). During the development of a generic film-coated tablet formulation, two clinical trials were done with three different experimental formulations to achieve a similar formulation to the reference one. A dissolution test procedure with a flow-through cell (USP IV) was used to predict the in vivo absorption behavior. The method proposed is based on a flow rate of 5 mL/min and changes of pH mediums from 1.2 to 4.5 and then to 6.8 with standard pharmacopoeia buffers. In order to improve the dissolution of montelukast, sodium dodecyl sulfate was added to the 4.5 and 6.8 pH mediums. Dissolution profiles in from the new method were used to develop a level-A IVIVC. One-step level-A IVIVC was developed from dissolution profiles and fractions absorbed obtained by the Loo–Riegelman method. Time scaling with Levy’s plot was necessary to achieve a linear IVIVC. One-step differential equation-based IVIVC was also developed with a time-scaling function. The developed method showed similar results to a previously proposed biopredictive method for montelukast, and the added value showed the ability to discriminate among different release rates in vitro, matching the in vivo clinical bioequivalence results.

Isolation of cytoskeletons from synchronized plant cells: the interphase microtubule array utilizes multiple tubulin isotypes

1987 ◽  
Vol 88 (2) ◽  
pp. 225-230
Author(s):  
PATRICK J. HUSSEY ◽  
JAN A. TRAAS ◽  
KEITH GULL ◽  
CLIVE W. LLOYD
Keyword(s):  
Plant Cells ◽  
Two Dimensional ◽  
Suspension Cells ◽  
Microtubule Array ◽  
Tubulin Isotypes ◽  
Interphase Cells ◽  
Plant Cytoskeleton ◽  
Carrot Protoplasts

Biochemical analysis of the plant cytoskeleton has been hampered by an inability to isolate anything more than cytoskeletal fragments. Methods for isolating entire detergent-resistant cytoskeletons from carrot suspension cells are now reported. This enables the expression of tubulin isotypes to be studied in functional microtubular arrays, freed of the soluble pool by detergent extraction. When osmotically cushioned with 0.4 M-sorbitol, microtubule-stabilizing buffer and dimethyl-sulphoxide, carrot protoplasts can be extracted by mild detergent, without fragmenting. Cytoskeletons isolated by sucrose density centrifugation are shown by electron and fluorescence microscopy to contain a complex meshwork of three major fibrous sytems: F-actin, microtubules and bundles of 7 nm fibrils. Plant cells can assemble tubulin into one of four microtubule arrays depending upon the phase of the cell cycle. Previous work had established that interphase cells contained multiple tubulin isotypes. However, the tubulins had been isolated by taxol assembly in vitro, which need not reflect patterns of usage by the interphase microtubule array in vivo. To address this problem, cells blocked in interphase were converted to cytoskeletons and their usage of tubulin isotypes determined by immunoblotting two-dimensional gels. This confirmed that all of the alpha and beta isotypes that can be identified on two-dimensional gels of carrot suspension cells are utilized by the interphase microtubule array. Note: Address for reprints

scholarly journals Electron-lucent inclusion bodies are structures specialized for aphid transmission of cauliflower mosaic virus

2007 ◽  
Vol 88 (10) ◽  
pp. 2872-2880 ◽  
Author(s):  
Mounia Khelifa ◽  
Sandra Journou ◽  
Kalpana Krishnan ◽  
Daniel Gargani ◽  
Pascal Espérandieu ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Inclusion Bodies ◽  
Infected Plant ◽  
Plant Cells ◽  
Aphid Transmission ◽  
Cauliflower Mosaic Virus ◽  
Single Amino Acid ◽  
Electron Lucent

Cauliflower mosaic virus (CaMV) is transmitted by aphids. For acquisition by the vector, a transmissible complex must form, composed of the virus particle, the viral coat-associated protein P3 and the helper protein P2. However, the components of the transmissible complex are largely separated in infected plant cells: most P3 virions are confined in electron-dense inclusion bodies, whereas P2 is sequestered in electron-lucent inclusion bodies (elIBs). This spatial separation controls virus acquisition by favouring the binding of virus-free P2 to the vector first, rendering the vector competent for later uptake of P3 virions. Consequently, sequential acquisition of virus from different cells or tissues is possible, with important implications for the biology of CaMV transmission. CaMV strains Campbell and CM1841 contain a single amino acid mutation (G94R) in the helper protein P2, rendering them non-transmissible from plant to plant. However, the mutant P2-94 protein supports aphid transmission when expressed heterologously and supplied to P3–CaMV complexes in vitro. The non-transmissibility of P2-94 was re-examined in vivo and it is shown here that the non-transmissibility of this P2 mutant is not due to low accumulation levels in infected plants, as suggested previously, but more specifically to the failure to form elIBs within infected plant cells. This demonstrates that elIBs are complex viral structures specialized for aphid transmission and suggests that viral inclusion bodies other than viral factories, most often considered as ‘garbage cans’, can in fact exhibit specific functions.

Mechanisms of Herbicide Absorption Across Plant Membranes and Accumulation in Plant Cells

Weed Science ◽  
1994 ◽  
Vol 42 (2) ◽  
pp. 263-276 ◽  
Author(s):  
Tracy M. Sterling
Keyword(s):  
Plant Cell ◽  
Cell Membranes ◽  
Plant Cells ◽  
Physicochemical Characteristics ◽  
Weak Acid ◽  
Ion Trapping ◽  
Metabolic Inhibitors ◽  
Plant Cell Membranes ◽  
Plant Membranes ◽  
Acid Herbicides

In most cases, a herbicide must traverse the cell wall, the plasma membrane, and organellar membranes of a plant cell to reach its site of action where accumulation causes phytotoxicity. The physicochemical characteristics of the herbicide molecule including lipophilicity and acidity, the plant cell membranes, and the electrochemical potential in the plant cell control herbicide absorption and accumulation. Most herbicides move across plant membranes via nonfacilitated diffusion because the membrane's lipid bilayer is permeable to neutral, lipophilic xenobiotics. Passive absorption of lipophilic, ionic herbicides or weak acids can be mediated by an ion-trapping mechanism where the less lipophilic, anionic form accumulates in alkaline compartments of the plant cell. A model that includes the pH and electrical gradients across plant cell membranes better predicts accumulation concentrations in plant cells of weak acid herbicides compared to a model that uses pH only. Herbicides also may accumulate in plant cells by conversion to nonphytotoxic metabolites, binding to cellular constituents, or partitioning into lipids. Evidence exists for herbicide transport across cell membranes via carrier-mediated processes where herbicide accumulation is energy dependent; absorption is saturable and slowed by metabolic inhibitors and compounds of similar structure.

Sign in / Sign up

Export Citation Format

Share Document