scholarly journals Detection of Genetically Modified Crops and Their Derivatives: Critical Steps in Sample Preparation and Extraction

2002 ◽  
Vol 85 (3) ◽  
pp. 768-774 ◽  
Author(s):  
Catherine F Terry ◽  
Neil Harris ◽  
Helen C Parkes
Keyword(s):  
Sample Preparation ◽  
Dna Analysis ◽  
Genetically Modified ◽  
Genetically Modified Crops ◽  
Analytical Techniques ◽  
Ease Of Use ◽  
Preparation Technique ◽  
Sample Matrix ◽  
Extraction And Purification ◽  
Polymerase Chain

Abstract The detection of genetically modified crops in foodstuff relies on detection of transgenic DNA or protein material in the sample matrix. Purified DNA or proteins are used as analytical material for polymerase chain reaction technologies and immunodiagnostics. Successful sample preparation is critical to the validity of subsequent analysis. For routine analysis, a good sample preparation technique should be simple, safe, and inexpensive while reproducibly generating DNA/protein of sufficient quality and yield. The suitability of isolated DNA or protein as an analyte for a detection or characterization technique depends on amount or concentration, purity, and integrity, each of which may be influenced by sample matrix and the extraction technique, and, in turn, may impact the validity of analytical techniques. The key sample preparation steps of homogenization, pretreatment, extraction, and purification are discussed as well as typical analytical methods. Consideration is given to application of these steps for particular sample matrixes to maximize yield, reduce inhibition effects, and minimize contamination. The choice of the most appropriate and valid methods for sample preparation from particular foods is discussed with respect to DNA analysis. Attention is also given to ease of use, cost, and generic applicability of the procedures.

Green sample preparation of complex matrices: towards sustainable separations of organic compounds based on the biorefinery concept

2016 ◽  
Vol 88 (1-2) ◽  
pp. 29-36 ◽  
Author(s):  
Vânia G. Zuin
Keyword(s):  
Sample Preparation ◽  
Organic Compounds ◽  
Analytical Techniques ◽  
Complex Matrices ◽  
Extraction And Purification ◽  
Sustainable Extraction ◽  
Green Sample

AbstractThe development and application of green analytical techniques aiming at the sample preparation of complex matrices for the study of organic compounds have been growing considerably over the last 15 years. Miniaturisation, automation and solventless techniques are gaining importance in this field, associated to others, as is the case of metrics. However, the unreflected use of the so-called green analytical techniques “might lead to doing the same things better, rather than rethinking solutions altogether”. Some limits and potentialities of the green sample preparation towards sustainable separations of organic compounds using the biorefinery concept will be also discussed in this paper, a promising biobased route that can integrate sustainable extraction and purification processes in a whole complete circular unity.

PCR for the detection of the anti-herbicide genes in genetically modified organisms

2006 ◽  
Vol 3 (1) ◽  
pp. 53-57
Author(s):  
Xu Wen-Tao ◽  
Huang Kun-Lun ◽  
Deng Ai-Ke ◽  
Luo Yun-Bo
Keyword(s):  
Polymerase Chain Reaction ◽  
Genetically Modified Organisms ◽  
Genetically Modified ◽  
Genetically Modified Crops ◽  
Routine Method ◽  
Chain Reaction ◽  
Pcr Screening ◽  
Invaluable Tool ◽  
Pcr Method ◽  
Polymerase Chain

AbstractGenetically modified organisms (GMOs) containing anti-herbicide genes account for more than 75% of all GMO and the proportion is increasing. The polymerase chain reaction (PCR) method has proved to be an invaluable tool for the specific and sensitive detection of genetically modified material in foodstuffs and PCR screening for the presence of transgenic components in food is becoming a routine method in modern food analysis. In this study, the five kinds of the anti-herbicide genes (bar, pat,cp4-epsps1,cp4epsps2andgox) were examined by PCR in four kinds of genetically modified crops (soy, maize, cotton and rape). Results indicate that the method was sensitive, specific and credible, and that all genetically modified and approved crops containing the anti-herbicide genes can be examined by this method.

scholarly journals Predicting Public Acceptance of Genetically Modified Crops in Ghana Using the Decomposed Theory of Planned Behaviour

2020 ◽  
pp. 33-45
Author(s):  
R. Ampadu-Ameyaw ◽  
J. Owusu-Arthur
Keyword(s):  
Theory Of Planned Behaviour ◽  
Genetically Modified ◽  
Genetically Modified Crops ◽  
Ease Of Use ◽  
Perceived Usefulness ◽  
Perceived Ease Of Use ◽  
Planned Behaviour ◽  
Initial Development ◽  
Factors Influencing ◽  
Positive Correlations

Public behaviour is a critical in determining factors influencing technology adoption and use. This study employs the Decomposed theory of planned behaviour to ascertain the factors influencing public behaviour, attitude and perception toward genetically modified crops in Ghana. This paper employs the views of 563 respondents from the media, agricultural extension and farmer groups in various regions of Ghana. The results of the study suggest there are significantly positive correlations between constructs of perceived usefulness, perceived ease of use and subjective norms leading to possible intention to accept GM technologies in the country. The study revealed that while the public holds a positive view of the technology, some important concerns that could limit the acceptance rate were listed. These include perceived high costs of GM seeds, monopoly of technological rights, health and other environmental risks. In many cases it was found that the understanding of the technology among the respondents was not encouraging. Many perceive the biologically oriented technology to be chemically oriented because the initial development of the product is laboratory oriented. The result, therefore begs for an immediate education and awareness creation on the merits and demerits of the technology in order to allay the fears of the pessimists. 

scholarly journals Neuropeptidomics: Improvements in Mass Spectrometry Imaging Analysis and Recent Advancements

2020 ◽  
Vol 21 ◽  
Author(s):  
Nhu Q. Vu ◽  
Kellen DeLaney ◽  
Lingjun Li
Keyword(s):  
Mass Spectrometry ◽  
Sample Preparation ◽  
Functional Role ◽  
Mass Spectrometry Imaging ◽  
Analytical Techniques ◽  
Model Organisms ◽  
Preparation Technique ◽  
Single Experiment ◽  
Recent Developments ◽  
Msi Analysis

: Neuropeptides are an important class of endogenous peptides in the nervous system that regulate physiological functions such as feeding, glucose homeostasis, pain, memory, reproduction, and many others. In order to understand the functional role of neuropeptides in diseases or disorders, studies investigating their dysregulation in terms of changes in abundance and localization must be carried out. Because multiple neuropeptides are believed to play a functional role in each physiological process, techniques capable of globally profiling multiple neuropeptides simultaneously are desired. Mass spectrometry is well-suited for this goal due to its ability to perform untargeted measurements without prior comprehensive knowledge of the analytes of interest. Mass spectrometry imaging (MSI) is particularly useful because it has the capability to image a large variety of peptides in a single experiment without labeling. Like all analytical techniques, careful sample preparation is critical to successful MSI analysis. The first half of this review focuses on recent developments in MSI sample preparation and instrumentation for analyzing neuropeptides and other biomolecules in which the sample preparation technique may be directly applicable for neuropeptide analysis. The benefit offered by incorporating these techniques is shown as improvement in number of observable neuropeptides, enhanced signal to noise, increased spatial resolution, or a combination of these aspects. The second half of this review focuses on recent biological discoveries about neuropeptides resulting from these improvements in MSI analysis. The recent progress in neuropeptide detection and analysis methods, including incorporation of various tissue washes, matrices, instruments, ionization sources, and computation approaches combined with the advancements in understanding neuropeptide function in a variety of model organisms indicates potential for the utilization of MSI analysis of neuropeptides in clinical settings.

SEM evaluation of the TEM cold-stage double-film specimen

1984 ◽  
Vol 42 ◽  
pp. 272-273
Author(s):  
Jayesh Bellare
Keyword(s):  
Spatial Distribution ◽  
Sample Preparation ◽  
Sample Thickness ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Liquid Sample ◽  
Thin Specimen ◽  
Sample Preparation Technique ◽  
Cold Stage ◽  
Film Specimen

Seeing is believing, but only after the sample preparation technique has received a systematic study and a full record is made of the treatment the sample gets.For microstructured liquids and suspensions, fast-freeze thermal fixation and cold-stage microscopy is perhaps the least artifact-laden technique. In the double-film specimen preparation technique, a layer of liquid sample is trapped between 100- and 400-mesh polymer (polyimide, PI) coated grids. Blotting against filter paper drains excess liquid and provides a thin specimen, which is fast-frozen by plunging into liquid nitrogen. This frozen sandwich (Fig. 1) is mounted in a cooling holder and viewed in TEM.Though extremely promising for visualization of liquid microstructures, this double-film technique suffers from a) ireproducibility and nonuniformity of sample thickness, b) low yield of imageable grid squares and c) nonuniform spatial distribution of particulates, which results in fewer being imaged.

A technique for preparing semiconductor cross sections for both TEM and SEM analysis

1989 ◽  
Vol 47 ◽  
pp. 712-713
Author(s):  
Stanley J. Klepeis ◽  
J.P. Benedict ◽  
R.M Anderson
Keyword(s):  
Sample Preparation ◽  
Cross Section ◽  
Cross Sections ◽  
Sem Analysis ◽  
Preparation Technique ◽  
Ion Milling ◽  
Tem Analysis ◽  
Polished Cross Section ◽  
Area Of Interest ◽  
Polished Side

The ability to prepare a cross-section of a specific semiconductor structure for both SEM and TEM analysis is vital in characterizing the smaller, more complex devices that are now being designed and manufactured. In the past, a unique sample was prepared for either SEM or TEM analysis of a structure. In choosing to do SEM, valuable and unique information was lost to TEM analysis. An alternative, the SEM examination of thinned TEM samples, was frequently made difficult by topographical artifacts introduced by mechanical polishing and lengthy ion-milling. Thus, the need to produce a TEM sample from a unique,cross-sectioned SEM sample has produced this sample preparation technique.The technique is divided into an SEM and a TEM sample preparation phase. The first four steps in the SEM phase: bulk reduction, cleaning, gluing and trimming produces a reinforced sample with the area of interest in the center of the sample. This sample is then mounted on a special SEM stud. The stud is inserted into an L-shaped holder and this holder is attached to the Klepeis polisher (see figs. 1 and 2). An SEM cross-section of the sample is then prepared by mechanically polishing the sample to the area of interest using the Klepeis polisher. The polished cross-section is cleaned and the SEM stud with the attached sample, is removed from the L-shaped holder. The stud is then inserted into the ion-miller and the sample is briefly milled (less than 2 minutes) on the polished side. The sample on the stud may then be carbon coated and placed in the SEM for analysis.

TEM sample preparation of wear-tested room-temperature pulsed-laser-deposited thin films of MoS2 by ultramicrotomy

1993 ◽  
Vol 51 ◽  
pp. 1118-1119
Author(s):  
Pamela F. Lloyd ◽  
Scott D. Walck
Keyword(s):  
Thin Films ◽  
Sample Preparation ◽  
Room Temperature ◽  
High Vacuum ◽  
Pulsed Laser ◽  
Ultra High Vacuum ◽  
Wear Testing ◽  
Preparation Technique ◽  
Cross Sectional ◽  
Aerospace Applications

Pulsed laser deposition (PLD) is a novel technique for the deposition of tribological thin films. MoS2 is the archetypical solid lubricant material for aerospace applications. It provides a low coefficient of friction from cryogenic temperatures to about 350°C and can be used in ultra high vacuum environments. The TEM is ideally suited for studying the microstructural and tribo-chemical changes that occur during wear. The normal cross sectional TEM sample preparation method does not work well because the material’s lubricity causes the sandwich to separate. Walck et al. deposited MoS2 through a mesh mask which gave suitable results for as-deposited films, but the discontinuous nature of the film is unsuitable for wear-testing. To investigate wear-tested, room temperature (RT) PLD MoS2 films, the sample preparation technique of Heuer and Howitt was adapted.Two 300 run thick films were deposited on single crystal NaCl substrates. One was wear-tested on a ball-on-disk tribometer using a 30 gm load at 150 rpm for one minute, and subsequently coated with a heavy layer of evaporated gold.

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