Search results for "bacteria."

Determination of aminoglycoside and macrolide antibiotics in meat by pressurized liquid extraction and LC-ESI-MS

2010

A simple method for the simultaneous determination of dihydrostreptomycin, spectinomycin, spiramycin, streptomycin, tilmicosin, and tylosin in meat has been developed using pressurized liquid extraction and LC-triple quadrupole MS (LC-ESI-MS/MS). The pressurized liquid extraction operational parameters were optimized and no protein precipitating and fat removing steps were required. A gradient HPLC separation was developed with ion-pair mobile phases consisting of aqueous 1 mM heptafluorobutyric acid water and methanol. Protonated molecules were used as precursor ions for CID. Data acquisition under MS/MS was achieved by applying multiple reaction monitoring of three fragment ion transition…

Antibakterielle Wirkstoffe, 6. Mitt.1) 2,4-Unsymmetrisch dialkylierte Pyrimido[1,2-a]benzimidazole

1982

Durch Kondensation von 2-Aminobenzimidazol (1) mit 2,4-Hexandion (2a) entsteht das Isomerenpaar 3a/3b, mit 6-Methyl-2,4-heptandion (2b) das Isomerengemisch 3c/3d, wahrend mit 1-Phenyl-2,4-pentandion (2c) die Isomere 3e und 3f gebildet werden. Die Trennung der Isomere ist durch Saulenchromatographie, die Strukturfestlegung auf spektroskopischem Wege, moglich. 2-Imino-2H-s-triazino[2,1-b]benzoxazol weist antibakterielle Wirksamkeit auf. Antibacterial Drugs, VI: 2,4-Unsymmetrically Dialkylated Pyrimido[1,2-α]benzimidazoles Condensation of 2-aminobenzimidazole (1) with 2,4-hexanedione (2a) leads to the pair of isomers 3a/3b. Condensation with 6-methyl-2,4-heptanedione (2b) yields the isomers 3c…

Bis- and trisporphyrin bio-inspired models for bacterial antennas and photosystems

2011

This review presents the synthetic aspects and photophysical properties of trimeric systems constructed with a first unit consisting of a cofacial porphyrin and then of another porphyrin attached as a side arm. Two scenarios are dealt with. The first one is the case where the three chromophores are different, called donor 1–donor 2–acceptor, specifically where the cofacial fragment is composed of donor 1 and donor 2, and the side arm is the acceptor. They are considered as models for the apo-proteins used in the LH II (light harvesting device) in the purple photosynthetic bacteria. The second one is the case where the chromophores of the cofacial bisporphyrin residue are identical and are …

Morphological Characterisation of Bacterial Cellulose-Starch Nanocomposites

2008

Acetobacter sp. growing medium was modified in order to produce bacterial cellulose (BC) nanocomposites using a bottom-up technique that allowed starch to be introduced into the cellulose network. The BC-starch mats were hot-pressed to obtain nanocomposites sheets. Morphological characterisation was carried out using Atomic Force Microscopy and Environmental Scanning Electron Microscopy. The images obtained from microscopy were then processed using image analysis. Network properties, such as mesh size and fibre orientation were characterised. Fracture surfaces of these new nanocomposites were analysed.

Assembly of iron oxide nanosheets at the air-water interface by leucine-histidine peptides

2021

The fabrication of inorganic nanomaterials is important for a wide range of disciplines. While many purely inorganic synthetic routes have enabled a manifold of nanostructures under well-controlled conditions, organisms have the ability to synthesize structures under ambient conditions. For example, magnetotactic bacteria, can synthesize tiny ‘compass needles’ of magnetite (Fe3O4). Here, we demonstrate the bio-inspired synthesis of extended, self-supporting, nanometer-thin sheets of iron oxide at the water–air interface through self-assembly using small histidine-rich peptides.

Back Cover: Promoter Activation in Δ hfq Mutants as an Efficient Tool for Specialized Metabolite Production Enabling Direct Bioactivity Testing (Ange…

2019

Five-Membered Heterocyclic Rings and Their Fused Derivatives

2015

Antibakterielle Wirkstoffe, 10. Mitt. 2-(Methylthioanilino)pyrimidine

1985

Phenazine antibiotics produced by fluorescent pseudomonads contribute to natural soil suppressiveness to Fusarium wilt

2009

Natural disease-suppressive soils provide an untapped resource for the discovery of novel beneficial microorganisms and traits. For most suppressive soils, however, the consortia of microorganisms and mechanisms involved in pathogen control are unknown. To date, soil suppressiveness to Fusarium wilt disease has been ascribed to carbon and iron competition between pathogenic Fusarium oxysporum and resident non-pathogenic F. oxysporum and fluorescent pseudomonads. In this study, the role of bacterial antibiosis in Fusarium wilt suppressiveness was assessed by comparing the densities, diversity and activity of fluorescent Pseudomonas species producing 2,4-diacetylphloroglucinol (DAPG) (phlD+) …

The primary structural photoresponse of phytochrome proteins captured by a femtosecond X-ray laser

2020

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