scholarly journals Cadmium Resistance, Microbial Biosorptive Performance and Mechanisms of a Novel Biocontrol Bacterium Paenibacillus sp. LYX-1

2021 ◽  
Author(s):  
Yixin Luo ◽  
Min Liao ◽  
Yuhao Zhang ◽  
Na Xu ◽  
Xiaomei Xie ◽  
...  
Keyword(s):  
Adsorption Mechanism ◽  
Brown Rot ◽  
Antagonistic Effect ◽  
Test Results ◽  
Efflux System ◽  
Cadmium Resistance ◽  
Dead Biomass ◽  
Paenibacillus Sp ◽  
Heavy Metal Efflux ◽  
Biocontrol Strain

Abstract In order to explore whether the newly discovered biocontrol strain Paenibacillus sp., LYX-1 having antagonistic effect on peach brown rot was resistant to Cd2+, a series of growth of strain LYX-1 under different Cd concentration and biosorption experiments were conducted to living and dead strain LYX-1. Meanwhile, the Cd2+ resistance and biosorption mechanisms were further identified by Cd-resistant genes, TEM, SEM-EDS, FTIR and XPS analysis. The results showed that strain LYX-1 could resist 50 mg/L Cd2+ and the adsorption process of both living and dead strain LYX-1 all satisfied the pseudo-second kinetic equation. Under pH 8.0 and at a dose of 1.0 g/L strain, the removal capacities of living and dead cells were as high as 90.39% and 75.67% at 20 mg/L Cd2+, respectively. For the adsorption isotherm test, results revealed that both Langmuir (R2=0.9704) and Freundlich (R2=0.9915) model could describe the Cd2+ biosorption well for living strain LYX-1. The maximum equilibrium biosorption capacities of living and dead biomass were 30.6790 and 24.3752 mg/g, respectively. The adsorption mechanism was controlled by chemisorption with -OH, -NH, -C=O, O=C-O, C-N, S2− and phosphate functional groups on the cell surface of strain LYX-1, which were further identified by XPS. The insignificant biosorption difference of living and dead biomass was caused by CzcD gene in strain LYX-1 detoxifying cadmium through the heavy metal efflux system. The above results indicated that strain LYX-1 had higher tolerance and fixed capacity to Cd2+.

scholarly journals Structure and mechanism of the tripartite CusCBA heavy-metal efflux complex

2012 ◽  
Vol 367 (1592) ◽  
pp. 1047-1058 ◽  
Author(s):  
Feng Long ◽  
Chih-Chia Su ◽  
Hsiang-Ting Lei ◽  
Jani Reddy Bolla ◽  
Sylvia V. Do ◽  
...  
Keyword(s):  
Fusion Protein ◽  
Metal Ions ◽  
Structural Information ◽  
Efflux System ◽  
Inner Membrane ◽  
Outer Membranes ◽  
Membrane Fusion Protein ◽  
Periplasmic Domain ◽  
Methionine Residues ◽  
Heavy Metal Efflux

Gram-negative bacteria frequently expel toxic chemicals through tripartite efflux pumps that span both the inner and outer membranes. The three parts are the inner membrane, substrate-binding transporter (or pump); a periplasmic membrane fusion protein (MFP, or adaptor); and an outer membrane-anchored channel. The fusion protein connects the transporter to the channel within the periplasmic space. One such efflux system CusCBA is responsible for extruding biocidal Cu(I) and Ag(I) ions. We previously described the crystal structures of both the inner membrane transporter CusA and the MFP CusB of Escherichia coli . We also determined the co-crystal structure of the CusBA adaptor–transporter efflux complex, showing that the transporter CusA, which is present as a trimer, interacts with six CusB protomers and that the periplasmic domain of CusA is involved in these interactions. Here, we summarize the structural information of these efflux proteins, and present the accumulated evidence that this efflux system uses methionine residues to bind and export Cu(I) and Ag(I). Genetic and structural analyses suggest that the CusA pump is capable of picking up the metal ions from both the periplasm and the cytoplasm. We propose a stepwise shuttle mechanism for this pump to export metal ions from the cell.

Study of Active Compounds from Red Cabbage (Brassica oleracea var. capitata f. Rubra) Extract as a Green Corrosion Inhibitor for API 5L Grade X60 Steel in NaCl 3.5% Environment

2016 ◽  
Vol 842 ◽  
pp. 24-30 ◽  
Author(s):  
Andi Rustandi ◽  
M. Akbar Barrinaya
Keyword(s):  
Corrosion Inhibitor ◽  
Adsorption Mechanism ◽  
Electrochemical Impedance ◽  
Test Results ◽  
Active Compounds ◽  
Red Cabbage ◽  
Tafel Polarization ◽  
Green Corrosion Inhibitor ◽  
Polarization Test ◽  
Cabbage Extract

Red cabbage extract has been investigated in this work whether it would perform as a green corrosion inhibitor for API 5L grade X60 steel in 3.5% NaCl environment. Based on the FTIR and LC-MS analysis the active compounds of corrosion inibitor were hydroxyl, carbonyl and cyanidin. The Tafel polarization test results showed that red cabbage extract performed as a mixed corrosion inhibitor and the Electrochemical Impedance Spectroscopy test results showed that the impedance, polarization resistance and capacitive resistance of steel surface increased with the addition of red cabbage corrosion inhibitor. Based on evaluation of the testing results red extract red cabbage performed significant corrosion inhibition effect. The inhibitor efficiency increases with increased corrosion inhibitor concentration and the optimum inhibitor percent efficiency achieved 81%. The adsorption mechanism of red cabbage corrosion inhibitor can be considered as a Langmuir Isotherm

Kinetics and Thermodynamics of Adsorbing Ni2+ from Waste Water onto a New Type Treated Attapulgite

2013 ◽  
Vol 791-793 ◽  
pp. 159-162
Author(s):  
Ding Yun Jiang ◽  
Ying Ying Shi ◽  
Liang Dong Feng ◽  
A Qing Yuan
Keyword(s):  
Adsorption Mechanism ◽  
Langmuir Model ◽  
Heating Process ◽  
Test Results ◽  
Order Model ◽  
Kinetics And Thermodynamics ◽  
Pseudo Second Order ◽  
New Type ◽  
Dsc Curves ◽  
Nickel Adsorption

A new method is proposed to treat attapulgite by freeze-dying and heating process. The photos of Scanning Electron Microscopy (SEM) on treated attapulgite show higher dispersion properties. TG and DSC curves of raw attapulgite and treated attapulgite indicated the contents of adsorption water, zeolite water and complexing water in the treated attapulgite are less than that of raw attapulgite. The test results of Nickel adsorption indicated the adsorption mechanism could be better described by pseudo-second order model and the thermodynamic curve of adsorption could be described with Langmuir model.

The Significance of Accelerated Laboratory Testing Methods Determining the Natural Durability of Wood

Holzforschung ◽  
1999 ◽  
Vol 53 (5) ◽  
pp. 449-458 ◽  
Author(s):  
J. Van Acker ◽  
H. Militz ◽  
M. Stevens
Keyword(s):  
Brown Rot ◽  
Soft Rot ◽  
Natural Durability ◽  
Test Results ◽  
Accelerated Tests ◽  
Hazard Class ◽  
Additional Information ◽  
Hardwood Species ◽  
Poria Placenta ◽  
Durability Testing

Summary Under laboratory conditions basidiomycete and soft rot tests were carried out on more than 20 hardwood species and 3 softwood species together with reference species to evaluate their natural durability according to the European standard EN 350 part 1. The basidiomycetes tests were carried out using Gloeophyllum trabeum, Coniophora puteana, Poria placenta and Coriolus versicolor, all fungal strains in malt agar tests and in agreement with the EN 113. Such tests did not provide a solid basis to classify all wood species according to known durability classes (EN 350, part 2). There was only a distinct differentiation noted between those species belonging to the group with a durability classified 1 to 3 and those classified 4 to 5. Conclusively, only limited additional information on durability of tropical hardwoods was gained from brown rot tests. Despite both types of laboratory tests on soft rot, prescribed in ENV 807 (vermiculite and soil) which show the essential differences to the basidiomycete test results, it has not been possible to classify the durability subdivisions in a more substantial way. Adding to these tests the durability classification, based upon a field stake test (EN 252) and a greenhouse accelerated stake test, was also carried out. Using this last method, results can be gathered more rapidly and consequently confirm the efficiency of lab tests. Generally it is perceived that lab tests and accelerated tests are important tools in the prediction of the natural durability of wood. To further improve the predictability value, durability testing would be enhanced when using a hazard class orientation. Therefore the function of the conclusive end product can be identified in a more obvious way.

scholarly journals Study on the Adsorption Mechanism of Graphene Oxide by Calcareous Sand in South China Sea

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Beifeng Lv ◽  
Wenjie Yu ◽  
Jiale Luo ◽  
Biao Qian ◽  
Mulugeta Belete Asefa ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Adsorption Mechanism ◽  
Langmuir Equation ◽  
Adsorption Properties ◽  
Test Results ◽  
Batch Experiments ◽  
Calcareous Sand ◽  
Initial Concentration ◽  
Ft Ir ◽  
The Relationship

To remove graphene oxide from wastewater, we used batch experiments with calcareous sand to recover GO. The adsorption properties and mechanisms of GO by calcareous sand were investigated by different characterization techniques. In this paper, the relationship between the coagulation of GO on calcareous sand and pH, calcareous sand content, GO initial concentration, and temperature was studied. The results show that calcareous sand can effectively adsorb GO from aqueous solution, the interaction of GO with calcareous sand achieved interaction equilibrium in 5 h, and the adsorption of GO by calcareous sand strongly depends on pH. The isotherm data fitted to a Langmuir equation. A possible mechanism can be expressed from FT-IR, XRD, Raman spectra, SEM, EDS, TEM, AFM, and XPS results. The test results indicate that calcareous sand is a potentially recoverable GO material.

scholarly journals Nano-metals forming bacteria in Egypt. I. Synthesis, characterization and effect on some phytopathogenic bacteria in vitro

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sahar Abd El-Fatah Zaki ◽  
Ayman Kamal ◽  
Nader A. Ashmawy ◽  
Alia A. Shoeib
Keyword(s):  
Antibacterial Activity ◽  
Brown Rot ◽  
Soft Rot ◽  
High Reactivity ◽  
Antagonistic Effect ◽  
Phytopathogenic Bacteria ◽  
Alternative Approach ◽  
Vis Spectroscopy ◽  
Dickeya Solani

AbstractBacterial metal reducers were isolated from water samples collected from harsh condition locations in Egypt. Four selected isolates were identified as Enterococcus thailandicus, Pseudomonas putida, Marinobacter hydrocarbonoclasticus, and P. geniculata for Copper (Cu), Iron (Fe), Cobalt (Co) and Zinc (Zn) Nanoparticles (NPs) production sequentially. Nitrate reductase enzyme was assayed for bacterial isolates which demonstrated that P. putida, and M. hydrocarbonoclasticus have the maximum enzyme production. The produced NPs were characterized by using XRD, TEM, UV–VIS spectroscopy. Magnetic properties for all selected metals NPs were measured using Vibrating Sample Magnetometer (VSM) and demonstrated that FeNPs recorded the highest magnetization value. The antibacterial activity of selected metals NPs was tested against some phytopathogenic bacteria causing the following diseases: soft rot (Pectobacterium carotovorum, Enterobacter cloacae), blackleg (Pectobacterium atrosepticum and Dickeya solani), brown rot (Ralstonia solanacearum), fire blight (Erwinia amylovora) and crown gall (Agrobacterium tumefaciens). All metals NPs showed an antagonistic effect against the tested isolates, particularly, FeNPs showed the highest antibacterial activity followed by CuNPs, and ZnNPs. Due to the small size, high reactivity, and large surface area of biologically synthesized NPs, they are used as a good disinfector, and can be considered as a new and alternative approach to traditional disease management methods.

scholarly journals Study on the optimal antagonistic effect of a bacterial complex against Monilinia fructicola in peach

2020 ◽  
Vol 15 (1) ◽  
pp. 890-901
Author(s):  
Haotian Chang ◽  
Haiqing Yang ◽  
Tao Han ◽  
Fang Wang ◽  
Yueping Liu
Keyword(s):  
Disease Management ◽  
Prunus Persica ◽  
Brown Rot ◽  
Antagonistic Effect ◽  
Monilinia Fructicola ◽  
Bacterial Strains ◽  
Soil Rhizosphere ◽  
Peach Trees ◽  
Bacterial Complex ◽  
Growth Of Seedlings

AbstractPeach brown rot caused by Monilinia fructicola is one of the most economically destructive diseases of peach (Prunus persica L.) in some orchards of China. Biocontrol is a significant strategy that exhibits strong levels of control and ecologically sound concepts in disease management. The purpose of this study was to investigate the combined suppressive effects of three endophytic bacterial strains (xj-14, xj-15, and xj-16) and two soil rhizosphere bacterial strains (xj-A and xj-C) that were shown to have strong inhibitory activity toward M. fructicola in our previous study. The optimal strains and the optimized combination of strains were determined. The combination of strains xj-15 and xj-C inhibited M. fructicola more intensively for a longer period of time. Following the application of 1 × 109 CFU/mL bacterial complex to the fruits, leaves, and shoots of peach trees infected with M. fructicola, the rate of inhibition reached 73.80%, 83.33%, and 90.43%, respectively. A pot experiment using lettuce (Lactuca sativa) showed that inoculation with the bacterial complex significantly increased the growth of seedlings. In this study, some compound bacteria were more effective than those in previous study in suppressing disease and promoting growth, which have the potential to be further applied in the field.

Using Conventional Articulation Tests With Highly Unintelligible Children

1992 ◽  
Vol 23 (1) ◽  
pp. 52-60 ◽  
Author(s):  
Pamela G. Garn-Nunn ◽  
Vicki Martin
Keyword(s):  
Test Results ◽  
Phonological Processes ◽  
Rule Based ◽  
Severity Level ◽  
Error Sensitivity ◽  
Conventional Tests ◽  
Severity Levels ◽  
Conventional Test ◽  
Impaired Children

This study explored whether or not standard administration and scoring of conventional articulation tests accurately identified children as phonologically disordered and whether or not information from these tests established severity level and programming needs. Results of standard scoring procedures from the Assessment of Phonological Processes-Revised, the Goldman-Fristoe Test of Articulation, the Photo Articulation Test, and the Weiss Comprehensive Articulation Test were compared for 20 phonologically impaired children. All tests identified the children as phonologically delayed/disordered, but the conventional tests failed to clearly and consistently differentiate varying severity levels. Conventional test results also showed limitations in error sensitivity, ease of computation for scoring procedures, and implications for remediation programming. The use of some type of rule-based analysis for phonologically impaired children is highly recommended.

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