Genetic diversity of ACC-deaminase positive bacteria in Colorado soil under winter wheat cultivars (Triticum aestivum L.)

2018 Spring.Includes bibliographical references.ACC-deaminase positive bacteria (ACC+) promote plant growth and development by lowering abiotic stress ethylene levels through deamination of 1-aminocyclopropane-1-carboxylic acid (ACC), the immediate precursor of ethylene. During drought stress, ACC+ bacteria can help plants better tolerate drought stress in arid and semi-arid areas such as Colorado. The purpose of this study was to assess the capability of ACC+ bacteria to support winter wheat cultivar growth and production under drought stress conditions. In a field study, the relative abundance and genetic diversity of ACC+ bacteria associated with four winter wheat cultivars (Baca, Hatcher, Ripper, and RonL) were assessed under dryland, limited irrigation, and fully irrigated conditions in Colorado. The abundance of ACC deaminase positive bacteria was relatively high, with numbers ranging between 1.69 × 107 and 3.28 × 109 CFU's g-1 soil. At anthesis, the abundance and relative percent of ACC+ bacteria were greater under dryland and limited irrigation compared to full irrigation, and greater under RonL than other cultivars. The composition of rhizosphere ACC+ bacteria was distinct under RonL compared to Ripper. The majority of ACC+ bacteria enriched from these soils were Proteobacteria, specifically Pseudomonas spp. These results suggest that cultivar was a stronger driver of community composition of ACC+ bacteria than irrigation practice. The second study was conducted using a total of 55 bacterial isolates from the original experimental soils (RonL, Ripper, and Hatcher), which were selected to assay for Plant-Growth Promoting (PGP) traits: ACC-deaminase activity, Indole Acetic Acid (IAA) production, osmotic stress tolerance, phosphorus solubilization, and siderophore production. Most isolates were identified as species of Pseudomonas, but other species such as Arthrobacter, Variovorax, Agrobacterium, Rhizobium, Ochrobacterium, Micrococcus, Rahnella, and Bacillus were represented as well. Out of 55 isolates, 47 bacterial isolates tolerated osmotic stress when tested at an osmotic stress of -0.73 MPa water potential, 42 isolates demonstrated ACC-deaminase activity (potential ACC-deaminase activity ranged from 0.012 to 4.36 nmoles mg-1 protein h-1), 16 isolates were capable of solubilizing rock phosphate, one isolate produced IAA in the presence of 200 µg mL-1 tryptophan, and none of the isolates produced siderophores in vitro. Seven bacterial isolates that exhibit multiple PGPRs traits were selected for a root elongation assay using winter wheat seeds. The isolates selected were three Pseudomonas sp. isolated from RonL rhizospheres in fully irrigated plots (RLF6, RLF9, and RLF12); one Variovorax sp. isolated from Ripper rhizosphere in a dryland plot (RD12), one Pseudomonas sp. from Ripper rhizosphere of a fully irrigated plot (RF12), and two Pseudomonas sp. isolated from Hatcher rhizospheres (HD8 and HF1). The results showed that 6 days after seeds were inoculated, Ripper seedlings had the longest roots. In addition, isolates RLF6 and RF12, both Pseudomonas sp., were found to be the most effective in increasing root length as compared to sterile inoculum (control). The effect of inoculation on root length, however, was dependent on cultivar type. A subsequent field plot study was conducted to test the effectiveness of Pseudomonas sp. RLF9 to improve wheat growth and productivity under drought stress. Inoculum was prepared in the form of alginate bead and distributed in trenches next to winter wheat plants (at stem elongation growth phase), in replicated field plots under irrigated and non-irrigated treatments. Six weeks after inoculation, numbers of culturable Pseudomonas sp. were greater (P ≤ 0.05) in soil inoculated with RLF9 than sterile inoculant, except for the RonL/Ripper bioculture treatment. Overall, soil under RonL accumulated the highest ACC-deaminase positive bacterial populations (1.8×105 CFUs g-1 soil) compared to other cultivar treatments. Soil ACC deaminase activity was highly variable but tended to be greatest in soil planted to monocultures of RonL and Ripper, and bicultures of RonL and Ripper. There was no significant correlation between inoculant abundance in soil and soil ACC-deaminase activity, perhaps because of ACC deaminase activity of indigenous soil bacteria. The field season was marked with abundant rainfall during the spring, followed by outbreaks of pathogens, including stripe rust, that affected all field treatments and confounded late season drought and heat stress. As a result, there were no irrigation treatment effects or inoculation effects on wheat yield indices. The findings of this study are very attractive for further field studies, which would be helpful in extending isolate use as PGP inocula for wheat production, especially in Colorado and perhaps other semi-arid regions. Specifically, inoculation of winter wheat cultivars with PGPR's containing ACC-deaminase and other PGP traits could be an effective approach for successful crop production. Selection of PGPR inoculants and wheat cultivar combinations for obtaining optimum responses should be considered in future studies. The ability of potential inoculants to survive in the rhizosphere, compete with indigenous microbial communities, and colonize roots should also be studied. Based on laboratory studies of potential PGPR activities, Pseudomonas sp. RLF9 and possibly Pseudomonas sp. RLF6 could be good inocula selection to improve wheat growth and productivity under drought stress. Further research is needed to demonstrate the effectiveness of RLF6 and RLF9 as effective inoculants in the field

Quantum Cryptography

Quantum cryptography could well be the first application of quantum mechanics at the individual quanta level. The very fast progress in both theory and experiments over the recent years are reviewed, with emphasis on open questions and technological issues.Comment: 55 pages, 32 figures; to appear in Reviews of Modern Physic

Design of heuristic fuzzy logic controller for liquid level control

Abstract-The objective of this paper is to develop a heuristic fuzzy logic controller (FLC) capable of driving the liquid level in the tank to a given set point. Firstly, the procedure of how to design a (FLC), using graphical user interface (GUI) in MATLAB, is explained, all the steps of defining the fuzzy sets are illustrated in the fuzzy inference system (FIS);choosing the fuzzy membership functions for the inputs and the output, for the process of level control and it's limits, is done in membership function editor; editing the fuzzy rules that needed to control the level in a water tank is achieved with rule viewer using rule editor; Finally, the simulation results obtained were compared with a classical controller (PID Controller) are very satisfactory

Ischemia Toes: A Rare Complication of Pheochromocytoma. A Case Report

The peripheral ischemia associated with pheochromocytoma is extremely rare. It is secondary to intense cutaneous vasoconstriction which is itself a result of excess catecholamines. The following report describes a patient who presented necrotic areas at the toes as a complication of malignant pheochromocytoma. We report this observation to recall this complication and to emphasize the need to discuss the diagnosis of pheochromocytoma in any ischemia chart whatever its location is

Preparation and Antibacterial Activity of Mixed Ligand Complexes of Co(II), Ni(II), Cu(II) and Cd(II) Derived from 1-Phenylazo-2-naphthol and Salicylaldehyde

The mixed ligand complexes of Co(II), Ni(II), Cu(II) and Cd(II) have been synthesized by using 1-phenylazo-2-naphthol as primary ligand and salicylaldehyde as secondary ligand. All the prepared complexes were identified and confirmed by elemental analyses (C, H and N), molar conductance measurements, infrared, electronic absorption and electron paramagnetic resonance. The elemental analysis data suggest that the stoichiometry of the complexes to be 1:1:1[M: L1: L2] ratio. The molar conductance measurements of the complexes indicate their non-electrolytic nature. The infrared spectral data showed the coordination sites of the free ligand with the central metal ion. The electronic absorption spectral data revealed the existence of an octahedral geometry for Co(II) and Cd(II) complexes and a square planar geometry for Ni(II) and Cu(II) complexes. The electron paramagnetic resonance spectra of the Co(II) and Cu(II) complexes showed the existence a paramagnetic phenomenon and supported their geometrical structures which confirmed by the electronic absorption spectra. The ligands and mixed ligand complexes have been tested on antibacterial activity against three strains of pathogenic bacteria such as Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginos

Synthesis and Antibacterial Activities of Some Schiff Bases

Schiff bases p-hydroxybenzylidene-2-carboxyaniline, p-nitrobenz-ylidene-2-carboxyaniline, p-(N, N-dimethyl)aminobenzylidene-2-carboxyaniline, N-(4-hydroxybezylidene)-benzene-1,2-diamine, N--(4-nitrobezylidene)benzene-1,2-diamine, N-(4-(N, N-dimethylaminobezylidene)benzene-1,2-diamine, N-(4-(N,N-dimethylamino)benzylidene)naphthalen-1-amine,N-(4-nitrobenzylidene)naphthalen-1-amine,N--(4-chlorobenzylidene)naphthalen-1-amine,sodium-4-(4-(N,N-dimethyl amino)benzylideneamino)naphthalene-1-sulfonate,sodium -4-(4-nitrobenzylidene-amino)naphthalene-1-sulfonate and sodium-4-(4-chlorobenzylideneamino) naphthalene-1-sulfonate obtained by condensation of aniline and naphthyl-amine derivatives with some aromatic aldehydes were characterized by physical and spectral methods. The biological activity of these products were as antibacterial agents against three species of human pathogenic bacteria such as Escherichia coli, Staphylococcus aureus and Klebsiella sp. Nearly 50% of these compounds showed reasonable activity against the bacterial species investigated and we found that the antibacterial activity is dependent on the molecular structure of the compounds

Low-coherence deformation sensors for the monitoring of civil-engineering structures

An optical-fiber deformation sensor with a resolution of 10 μm and an operational range of 60 mm has been realized. The system is based on low-coherence interferometry in standard single-mode telecommunication fibers. It allows the monitoring of large structures over several months without noticeable drift. No continuous measurement is needed and the system is insensitive to variations of the fiber losses. This technique has been applied to the monitoring of a 20 m × 5 m × 0.5 m, 120 ton concrete slab over six months. It is possible to measure the shrinkage of concrete and its elastic coefficient during pre-straining, giving reproducible results in good agreement with theoretical calculations and measurements performed on small concrete samples. This paper describes the optical arrangement and the procedures used to install optical fibers in concrete