Overview of Physical-Chemical Methods for Determining Aminoglycoside Antibiotics in Tissues and Fluids of Food-Producing Animals

1985 ◽  
Vol 68 (5) ◽  
pp. 1007-1013
Author(s):  
Badar Shaikh ◽  
Edward H Allen
Keyword(s):  
Liquid Chromatography ◽  
Aminoglycoside Antibiotics ◽  
Biological Matrices ◽  
Chemical Methods ◽  
Physical Chemical ◽  
Recent Developments

Abstract A survey of literature is presented dealing with physical-chemical methods for the detection and quantitation of aminoglycoside antibiotics (gentamicin, streptomycin, dihydrostreptomycin, and neomycin) that are used in food-producing animals. Recent developments in cleanup and determinative procedures, particularly liquid chromatography, for these compounds in fluids and tissues are emphasized. Little research has been done on residues in tissues compared with other biological matrices. This review also covers the chemistry, general characteristics, tolerances, and withdrawal times for the approved uses of these antibiotics in animals that are used for food.

Bitter Substances in the Hop Lupulin

2014 ◽  
Vol 1 (1) ◽  
pp. 20-25
Author(s):  
M. Liashenko ◽  
L. Protsenko ◽  
R. Rudyk ◽  
O. Svirchevska
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Quality Indicators ◽  
High Performance ◽  
Chemical Methods ◽  
Physical Chemical

Aim. To investigate the quantity and structure of α-, β-acids and xanthohumol in lupulin grains of different hop varieties that essentially differ in these biochemical indexes, and also the presence of the substances both in staminate racemes and in the leaves. Methods. High performance liquid chromatography (HPLC), up-to- date physical-chemical methods of hop quality indicators’ defi nition, special and standard in the hop-growing branch, were applied. Results. It was stated that lupulin of aroma and bitter varieties contains various quantity of α- and β-acids. Therefore, the ratio of α- to β-acids in aroma hop varieties is above one (1), whereas in varieties of bitter type this ratio is much lower than one (1). No correlation between the quantity of lupulin and the contents of α- and β-acids was found. It was noted that the color of lupulin depends upon the quantity of xanthohumol. Conclusions. The performed tests give evidences on lupulin glands are located on anthers of staminate racemes and on the leaves as well, though in much less quantity and less educed. It was found that the quantity and structure of bitter substances in lupulin grains from selection varieties does not depend upon lupulin content in hop cones, but it is a grading factor. Lupulin from the staminate racemes received from various plants essentially differs in quantity of α- and β-acids. This fact is of key importance for pair selection. In petal glands on the leaves of a hop plant bitter substances are represented only by β-acids, mainly lupulone and adlupulone.

Transmission Electron Microscopy of Protein Macromolecules

1971 ◽  
Vol 29 ◽  
pp. 424-425
Author(s):  
Henry S. Slayter
Keyword(s):  
Biological Systems ◽  
Metal Vapor ◽  
Resolving Power ◽  
Electron Microscopic ◽  
Chemical Methods ◽  
Molecular Weights ◽  
The Past ◽  
Physical Chemical ◽  
Transmission Electron

Electron microscopic methods have been applied increasingly during the past fifteen years, to problems in structural molecular biology. Used in conjunction with physical chemical methods and/or Fourier methods of analysis, they constitute powerful tools for determining sizes, shapes and modes of aggregation of biopolymers with molecular weights greater than 50, 000. However, the application of the e.m. to the determination of very fine structure approaching the limit of instrumental resolving power in biological systems has not been productive, due to various difficulties such as the destructive effects of dehydration, damage to the specimen by the electron beam, and lack of adequate and specific contrast. One of the most satisfactory methods for contrasting individual macromolecules involves the deposition of heavy metal vapor upon the specimen. We have investigated this process, and present here what we believe to be the more important considerations for optimizing it. Results of the application of these methods to several biological systems including muscle proteins, fibrinogen, ribosomes and chromatin will be discussed.

Folding of peptides and proteins: role of disulfide bonds, recent developments

2013 ◽  
Vol 4 (6) ◽  
pp. 597-604 ◽  
Author(s):  
Yuji Hidaka ◽  
Shigeru Shimamoto
Keyword(s):  
Protein Folding ◽  
Disulfide Bonds ◽  
Bond Formation ◽  
Difficult Problem ◽  
Chemical Methods ◽  
Mutant Proteins ◽  
Folding Intermediates ◽  
Peptide Chemistry ◽  
Recent Developments

AbstractDisulfide-containing proteins are ideal models for studies of protein folding as the folding intermediates can be observed, trapped, and separated by HPLC during the folding reaction. However, regulating or analyzing the structures of folding intermediates of peptides and proteins continues to be a difficult problem. Recently, the development of several techniques in peptide chemistry and biotechnology has resulted in the availability of some powerful tools for studying protein folding in the context of the structural analysis of native, mutant proteins, and folding intermediates. In this review, recent developments in the field of disulfide-coupled peptide and protein folding are discussed, from the viewpoint of chemical and biotechnological methods, such as analytical methods for the detection of disulfide pairings, chemical methods for disulfide bond formation between the defined Cys residues, and applications of diselenide bonds for the regulation of disulfide-coupled peptide and protein folding.

Developments in mycotoxin analysis: an update for 2015-2016

2017 ◽  
Vol 10 (1) ◽  
pp. 5-29 ◽  
Author(s):  
F. Berthiller ◽  
C. Brera ◽  
M.H. Iha ◽  
R. Krska ◽  
V.M.T. Lattanzio ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Critical Review ◽  
Analytical Methods ◽  
Ergot Alkaloids ◽  
Sampling Strategies ◽  
Liquid Chromatography Mass Spectrometry ◽  
Recent Developments ◽  
Mycotoxin Analysis

This review summarises developments in the determination of mycotoxins over a period between mid-2015 and mid-2016. Analytical methods to determine aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxins, patulin, trichothecenes and zearalenone are covered in individual sections. Advances in proper sampling strategies are discussed in a dedicated section, as are methods used to analyse botanicals and spices and newly developed liquid chromatography mass spectrometry based multi-mycotoxin methods. This critical review aims to briefly discuss the most important recent developments and trends in mycotoxin determination as well as to address limitations of presented methodologies.

Recent advances in the application of noble metal nanoparticles in colorimetric sensors for lead ions

2021 ◽  
Author(s):  
H Singh ◽  
Amy Bamrah ◽  
Sanjeev Kumar ◽  
A Deep ◽  
M Khatri ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Metal Nanoparticles ◽  
Noble Metal ◽  
Chemical Properties ◽  
Lead Ions ◽  
Noble Metal Nanoparticles ◽  
Physical Chemical ◽  
Recent Advances ◽  
Recent Developments ◽  
Colorimetric Sensors

Recent developments in nanotechnology and engineering have produced a plethora of nanomaterials with amazing physical/chemical properties and enhanced sensing potential for various heavy metals in the environment. Noble metal nanoparticles...

Study of the structure of polyphenylsiloxanes containing the metal-ions by physical–chemical methods

2017 ◽  
Vol 1145 ◽  
pp. 300-308 ◽  
Author(s):  
N.P. Shapkin ◽  
V.I. Razov ◽  
V.V. Korochentsev ◽  
E.A. Tokar ◽  
S.V. Gardionov ◽  
...  
Keyword(s):  
Metal Ions ◽  
Chemical Methods ◽  
Physical Chemical
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