scholarly journals Degradation of 1,3-Dichloropropene by Pseudomonas cichorii 170

1998 ◽  
Vol 64 (8) ◽  
pp. 2931-2936 ◽  
Author(s):  
Gerrit J. Poelarends ◽  
Marga Wilkens ◽  
Michael J. Larkin ◽  
Jan Dirk van Elsas ◽  
Dick B. Janssen
Keyword(s):  
Pcr Analysis ◽  
Rhodococcus Rhodochrous ◽  
Negative Bacterium ◽  
Haloalkane Dehalogenase ◽  
Positive Bacterium ◽  
Pseudomonas Cichorii ◽  
Low Concentrations ◽  
Suicide Substrate ◽  
Chloroacrylic Acid Dehalogenase ◽  
Acid Semialdehyde

ABSTRACT The gram-negative bacterium Pseudomonas cichorii 170, isolated from soil that was repeatedly treated with the nematocide 1,3-dichloropropene, could utilize low concentrations of 1,3-dichloropropene as a sole carbon and energy source. Strain 170 was also able to grow on 3-chloroallyl alcohol, 3-chloroacrylic acid, and several 1-halo-n-alkanes. This organism produced at least three different dehalogenases: a hydrolytic haloalkane dehalogenase specific for haloalkanes and two 3-chloroacrylic acid dehalogenases, one specific for cis-3-chloroacrylic acid and the other specific for trans-3-chloroacrylic acid. The haloalkane dehalogenase and thetrans-3-chloroacrylic acid dehalogenase were expressed constitutively, whereas the cis-3-chloroacrylic acid dehalogenase was inducible. The presence of these enzymes indicates that 1,3-dichloropropene is hydrolyzed to 3-chloroallyl alcohol, which is oxidized in two steps to 3-chloroacrylic acid. The latter compound is then dehalogenated, probably forming malonic acid semialdehyde. The haloalkane dehalogenase gene, which is involved in the conversion of 1,3-dichloropropene to 3-chloroallyl alcohol, was cloned and sequenced, and this gene turned out to be identical to the previously studieddhaA gene of the gram-positive bacterium Rhodococcus rhodochrous NCIMB13064. Mutants resistant to the suicide substrate 1,2-dibromoethane lacked haloalkane dehalogenase activity and therefore could not utilize haloalkanes for growth. PCR analysis showed that these mutants had lost at least part of the dhaA gene.

MXene Nanosheets May Induce Toxic Effect on the Early Stage of Embryogenesis

2020 ◽  
Vol 16 (3) ◽  
pp. 364-372 ◽  
Author(s):  
Hashim Alhussain ◽  
Robin Augustine ◽  
Essraa A. Hussein ◽  
Ishita Gupta ◽  
Anwarul Hasan ◽  
...  
Keyword(s):  
Toxic Effect ◽  
Biomedical Applications ◽  
Normal Development ◽  
Early Stage ◽  
Chorioallantoic Membrane ◽  
Pcr Analysis ◽  
Rt Pcr ◽  
Potential Toxicity ◽  
Avian Embryos ◽  
Low Concentrations

MXene (Ti3C2Tx), as a novel 2D material, has produced a great interest due to its promising properties in biomedical applications, nevertheless, there is a lack of studies dedicated to investigate the possible toxic effect of MXene in embryos. Herein, we aim to scrutinize the potential toxicity of MXene nanosheets on the early stage of the embryo as well as angiogenesis. Avian embryos at 3 and 5 days of incubation were used as an experimental model in this investigation. Our findings reveal that MXene may produce adverse effect on the early stage of embryogenesis as ∼46% of MXene-exposed embryos died during 1–5 days after exposure. We also found that MXene at tested concentration inhibits angiogenesis of the chorioallantoic membrane of the embryo after 5 days of incubation. More significantly, RT-PCR analysis of seven genes, which are key regulators of cell proliferation, survival, cell death and angiogenesis, revealed that these genes were deregulated in brain, heart and liver tissues from MXene-treated embryos in comparison with their matched controls. Our study clearly suggests that MXene at studied concentration might induce a toxic effect on the early stage of embryogenesis; nevertheless, more investigations are necessary to understand the effect at low concentrations and elucidate its mechanism at the early stage of normal development.

scholarly journals The Plasmid-Located Haloalkane Dehalogenase Gene from Rhodococcus Rhodochrous NCIMB 13064

Microbiology ◽  
1997 ◽  
Vol 143 (1) ◽  
pp. 109-115 ◽  
Author(s):  
A. N. Kulakova ◽  
M. J. Larkin ◽  
L. A. Kulakov
Keyword(s):  
Rhodococcus Rhodochrous ◽  
Haloalkane Dehalogenase ◽  
Dehalogenase Gene

scholarly journals The study of antibacterial activity and stability of dyed cotton fabrics modified with different forms of silver

2012 ◽  
Vol 77 (2) ◽  
pp. 225-234 ◽  
Author(s):  
Vesna Lazic ◽  
Zoran Saponjic ◽  
Vesna Vodnik ◽  
Suzana Dimitrijevic ◽  
Petar Jovancic ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Antibacterial Activity ◽  
Active Component ◽  
Silver Chloride ◽  
Cotton Fabrics ◽  
Negative Bacterium ◽  
Positive Bacterium ◽  
Vat Dyes ◽  
Artificial Sweat ◽  
The Stability

This study compares the effect of colloidal silver nanoparticles and commercial RUCO-BAC AGP agent with silver chloride as an active component on antibacterial activity of dyed cotton fabrics. Cotton fabrics were dyed with vat dyes Bezanthren olive T and Bezanthren grey FFB. Antibacterial activity of silver loaded dyed cotton fabrics was tested against Gram-positive bacterium Staphylococcus aureus and Gram-negative bacterium Escherichia coli. Unlike RUCO-BAC AGP synthesized silver nanoparticles deposited onto dyed cotton fabrics provided maximum bacteria reduction independently of applied dye. The stability of modified cotton fabrics was analyzed in artificial sweat at pH 5.5 and 8.0. Approximately the same amount of silver was released from differently modified cotton fabrics in artificial sweat. Larger amount of silver was released in the sweat at pH 8.0.

Functional Behaviour of Polyethylene-ZnO Nanocomposites

2008 ◽  
Vol 8 (8) ◽  
pp. 4121-4126 ◽  
Author(s):  
N. Vigneshwaran ◽  
A. K. Bharimalla ◽  
Virendra Prasad ◽  
A. A. Kathe ◽  
R. H. Balasubramanya
Keyword(s):  
Large Scale ◽  
Morphological Analysis ◽  
Visible Spectrum ◽  
Soluble Starch ◽  
Nanocomposite Materials ◽  
Zinc Nitrate ◽  
Negative Bacterium ◽  
Positive Bacterium ◽  
Mass Approximation ◽  
Uv Visible

Hybrid inorganic–organic nanocomposite materials are of current interest because of their multi-functionality, ease of processability, and potential for large-scale manufacturing. The focus of this study is to ascertain the functional properties of the commodity plastic impregnated with ZnO/starch nanocomposites. ZnO/starch nanocomposites was prepared by a simple process using zinc nitrate and sodium hydroxide as precursor and soluble starch as stabilizing agent. The peak obtained in terms of wavelength from UV-visible spectrum is converted in terms of particle size using effective mass approximation method. The plastic sheet of 50 μm thickness was prepared by hot blow method using 1:1 ratio of HDPE:LLDPE and 1% concentration of ZnO/starch nanocomposites. The morphological analysis was carried out using both optical and scanning electron microscopy. For antibacterial activity, evaluation was carried out with Staphylococcus aureus (AATCC 6538), a Gram-positive bacterium and Klebsiella pneumoniae (AATCC 4352), a Gram-negative bacterium. Excellent UV blocking ability was noticed in nanocomposites when compared to the control.

scholarly journals Enhanced tolerance of Deschampsia antarctica Desv. to the mutagenic effect of cadmium ions

2016 ◽  
Vol 14 (1) ◽  
pp. 63-71
Author(s):  
K. V. Spiridonova ◽  
I. O. Andreev ◽  
O. M. Zahrychuk ◽  
N. M. Drobyk ◽  
V. A. Kunakh
Keyword(s):  
Mutagenic Effect ◽  
Pcr Analysis ◽  
Deschampsia Antarctica ◽  
Genetic Changes ◽  
Cadmium Ions ◽  
Inhibition Of Growth ◽  
Low Concentrations ◽  
Pcr Products ◽  
Harsh Conditions

Aim. To study the potential effects of different concentrations of cadmium ions on antarctic plant D. antarctica using PCR analysis. Methods. Plants were grown in vitro on B5 Gamborg and Eveleigh agar medium supplemented with CdCl2. Genetic rearrangements were studied by PCR-analysis using ISSR- and IRAP-primers. Results. Genetically identical plants of D. antarctica obtained by microclonal propagation in vitro were used for the study of mutagenic effect of cadmium ions. The influence of Cd2+ was investigated within the concentration ranging from 0.1 to 10 mM. The results of cultivation of D. antarctica plants in the presence of cadmium ions for 63 days allow to determine the concentration range that does not inhibit the growth of the plants in vitro, and it was up to 1 mM. It was found that toxicant concentrations of 0.1 and 0.2 mM did not cause changes in the profiles of PCR products. After growing the plants with 0.2–1 mM CdCl2 for 17 days, the changes in the profiles of PCR products, indicating the mutagenic impact, were observed at concentrations of 0.6 mM or above; moreover, the number of changes increased in dependence on the concentration of heavy metal. Prolonged influence (140-265 days) of cadmium ions in relatively low concentrations (0.1 mM and 0.4 mM) did not cause detectable mutations. Conclusions. D. antarctica, a plant extremophile, which has evolved mechanisms of resistance to a variety of extreme conditions as a result of adaptation to the existence in the harsh conditions of Antarctica, shows enhanced resistance to cadmium ions in comparison with other species of vascular plants. Inhibition of growth occurs at Cd2+ concentrations of 0.1 mM or above, whereas concentrations of 1 mM or above cause cessation of growth and death of plants. Mutagenic effect on D. antarctica was observed at Cd2+ concentrations of above 0.4 mM. After prolonged growth of plants (for 3–8 months) at cadmium ions concentrations of 0.1–0.4 mM, genetic changes was not found.Keywords: Deschampsia antarctica Desv., plants in vitro obtained by microclonal propagation, cadmium ions, mutagenic effect, PCR-analysis.

scholarly journals Helicobacter pylori.

1997 ◽  
Vol 10 (4) ◽  
pp. 720-741 ◽  
Author(s):  
B E Dunn ◽  
H Cohen ◽  
M J Blaser
Keyword(s):  
Helicobacter Pylori ◽  
Gastric Lymphoma ◽  
Developed Countries ◽  
Pcr Analysis ◽  
Gastric Tissue ◽  
Negative Bacterium ◽  
Breath Tests ◽  
Ulcer Disease ◽  
Gastric Lumen ◽  
H Pylori

Helicobacter pylori is a gram-negative bacterium which causes chronic gastritis and plays important roles in peptic ulcer disease, gastric carcinoma, and gastric lymphoma. H. pylori has been found in the stomachs of humans in all parts of the world. In developing countries, 70 to 90% of the population carries H. pylori. In developed countries, the prevalence of infection is lower. There appears to be no substantial reservoir of H. pylori aside from the human stomach. Transmission can occur by iatrogenic, fecal-oral, and oral-oral routes. H. pylori is able to colonize and persist in a unique biological niche within the gastric lumen. All fresh isolates of H. pylori express significant urease activity, which appears essential to the survival and pathogenesis of the bacterium. A variety of tests to diagnose H. pylori infection are now available. Histological examination of gastric tissue, culture, rapid urease testing, DNA probes, and PCR analysis, when used to test gastric tissue, all require endoscopy. In contrast, breath tests, serology, gastric juice PCR, and urinary excretion of [15N]ammonia are noninvasive tests that do not require endoscopy. In this review, we highlight advances in the detection of the presence of the organism and methods of differentiating among types of H. pylori, and we provide a background for appropriate chemotherapy of the infection.

scholarly journals Suppression of Canola (Brassica napus) Resistance by Virulent Isolates of Plasmodiophora brassicae (Clubroot) During Primary Infection

Plant Disease ◽  
2020 ◽  
Vol 104 (2) ◽  
pp. 430-437
Author(s):  
Junye Jiang ◽  
Rudolph Fredua-Agyeman ◽  
Stephen E. Strelkov ◽  
Sheau-Fang Hwang
Keyword(s):  
Brassica Napus ◽  
Plasmodiophora Brassicae ◽  
Negative Control ◽  
Pcr Analysis ◽  
High Concentration ◽  
Clubroot Disease ◽  
Low Concentrations ◽  
High Concentrations ◽  
Experimental Treatments ◽  
Positive Controls

The planting of clubroot resistant (CR) canola (Brassica napus) is the most effective method to manage clubroot. Since 2013, many Plasmodiophora brassicae isolates capable of overcoming resistance have been detected, often in mixtures with avirulent isolates. To improve understanding of the effect of low concentrations of virulent isolates on host resistance, three CR canola cultivars (45H29, L135C, and L241C) were inoculated with pairs of isolates representing virulent/avirulent pathotypes (2*/2, 3*/3, and 5*/5) collected after or before the introduction of CR canola, respectively. Seven-day-old seedlings of each cultivar were incubated for 2 days in low concentrations (1 × 103 spores/ml) of the virulent isolates, followed by a second inoculation with a high concentration (1 × 107 spores/ml) of the avirulent isolates. Positive controls comprised seedlings inoculated with low concentrations of the virulent isolates followed by high concentrations of the virulent isolates (PC1) or only with high concentrations of virulent isolates (PC2). Negative controls comprised seedlings inoculated only with high concentrations of the avirulent isolates (NC1) or only with low concentrations of the virulent isolates (NC2). Clubroot severity was significantly higher in all nine experimental treatments (low virulent plus high avirulent) than in the negative control NC1 (high avirulent) but was lower in the experimental treatments than in the positive controls (PC1 and PC2). Low concentrations of virulent isolates alone (NC2) caused moderate clubroot. Disease severity correlated well with P. brassicae biomass in canola as determined by quantitative PCR analysis 28 to 35 days after inoculation. This study revealed that low concentrations of virulent isolates compromised canola resistance for infection by avirulent isolates.

scholarly journals Mechanisms of Antibacterial Action of Three Monoterpenes

2005 ◽  
Vol 49 (6) ◽  
pp. 2474-2478 ◽  
Author(s):  
Domenico Trombetta ◽  
Francesco Castelli ◽  
Maria Grazia Sarpietro ◽  
Vincenza Venuti ◽  
Mariateresa Cristani ◽  
...  
Keyword(s):  
Water Solubility ◽  
Lipid Fraction ◽  
Antimicrobial Effect ◽  
Physicochemical Characteristics ◽  
Water Soluble ◽  
Negative Bacterium ◽  
Positive Bacterium ◽  
Linalyl Acetate ◽  
Scanning Calorimetry ◽  
Fluorescent Marker

ABSTRACT In the present paper, we report the antimicrobial efficacy of three monoterpenes [linalyl acetate, (+)menthol, and thymol] against the gram-positive bacterium Staphylococcus aureus and the gram-negative bacterium Escherichia coli. For a better understanding of their mechanisms of action, the capability of these three monoterpenes to damage biomembranes was evaluated by monitoring the release, following exposure to the compounds under study, of the water-soluble fluorescent marker carboxyfluorescein from unilamellar vesicles with different lipidic compositions (phosphatidylcholine, phosphatidylcholine/phosphatidylserine [9:1], phosphatidylcholine/stearylamine [9:1], and phosphatidylglycerol/cardiolipin [9:1]). Furthermore, the interaction of the terpenes tested with dimyristoylphosphatidylcholine multilamellar vesicles as model membranes was monitored by means of differential scanning calorimetry. Finally, the results were related to the relative lipophilicity and water solubility of the compounds examined. Taken together, our findings lead us to speculate that the antimicrobial effect of (+)menthol, thymol, and linalyl acetate may result, at least partially, from a perturbation of the lipid fraction of microorganism plasma membrane, resulting in alterations of membrane permeability and in leakage of intracellular materials. Besides being related to physicochemical characteristics of the drugs (such as lipophilicity and water solubility), this effect seems to be dependent on lipid composition and net surface charge of microbial membranes. Furthermore, the drugs might cross the cell membranes, penetrating into the interior of the cell and interacting with intracellular sites critical for antibacterial activity.

Selective Adsorption of Microorganisms onto Artificial Siderophore-Modified Glass Surface

2006 ◽  
Vol 11-12 ◽  
pp. 251-256
Author(s):  
Tomohiko Inomata ◽  
Kenji Matsumoto ◽  
Yasuhiro Funahashi ◽  
Tomohiro Ozawa ◽  
Hideki Masuda
Keyword(s):  
Glass Substrate ◽  
Selective Adsorption ◽  
Substrate Surface ◽  
Stable Complex ◽  
Amine Group ◽  
Negative Bacterium ◽  
Positive Bacterium ◽  
Gram Negative ◽  
Glass Substrates ◽  
Self Assembling

The hydroxamate-based artificial siderophore that contains terminated-amine group was newly synthesized. This artificial siderophore formed stable complex with FeIII ion and high bio-activities. The FeIII-artificial siderophore complex was attached onto the glass substrate surface by stepwise self-assembling method. The obtained artificial siderophore-modified glass substrate adsorbed the Gram-positive bacterium Microbacterium. flavescens. The Gram-negative bacterium Escherichia. coli was not adsorbed. The artificial siderophore-modified glass substrates indicated the selective adsorption of microorganisms.

scholarly journals Investigating the antibacterial potential of agarose nanoparticles synthesized by nanoprecipitation technology

2016 ◽  
Vol 18 (2) ◽  
pp. 9-12 ◽  
Author(s):  
Rukhsana Satar ◽  
Syed Ahmed Iizhar ◽  
Mahmood Rasool ◽  
Peter Natesan Pushparaj ◽  
Shakeel Ahmed Ansari
Keyword(s):  
Negative Bacterium ◽  
Zone Of Inhibition ◽  
Positive Bacterium ◽  
Gram Negative ◽  
Force Microscopy ◽  
E Coli ◽  
Atomic Force ◽  
Colony Forming Units ◽  
Liquid Systems ◽  
Antibacterial Potential

Abstract Herein, an effort was made to investigate the antibacterial potential of agarose nanoparticles (ANPs) and poly(quaternary ammonium) modified ANPs (mANPs) against Escherichia coli (gram-negative bacterium) and Staphylococcus aureus (gram positive bacterium) in liquid systems as well as on agar plates. ANPs were synthesized by nanoprecipitation technology and characterized by XRD, TEM, TGA, DTA and DLS. The particle size estimated was 30 nm while atomic force microscopy was used to observe the interaction of ligand on ANPs. Antimicrobial characterization was monitored by colony forming units (CFU) as a function of ANPs concentration on agar plates. It was observed that ANPs showed 15 × 109/ml CFU after 24 hours of incubation at 20 mM ANPs concentration while the modified ANPs exhibited 21 × 109/ml CFU under similar incubation conditions. Moreover, zone of inhibition (ZOI) was 2.9 and 3.8 cm, respectively for E. coli by ANPs at 0.2 and 0.4 mM, respectively while it was 3.2 and 3.8 cm respectively by modified ANPs under similar conditions. Similarly, ZOI for S. aureus by ANPs at 0.2 and 0.4 mM was observed at 3.1 and 4.0 cm, respectively, while these values were 3.5 and 4.1 cm, respectively for modified ANPs under similar incubation conditions.

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