The Genetic Modification Advisory Committee was established in Singapore in April 1999 to oversee and advise on the research and development, production, use and handling of Genetically Modified Organisms (GMOs) in Singapore.
The objective of this committee was to ensure public safety while allowing for the commercial use of GMOs and GMO-derived products by companies and research institutions, in compliance with international standards.
GMAC will be developing and approving biosafety guidelines regarding GMOs, as well as facilitating the harmonisation of guidelines with international authorities.
OBJECTIVES OF GUIDELINES
These guidelines are established to ensure the safe containment, handling and transport of genetically modified organisms used in research and to provide a common framework for assessment and notification of research on GMOs.
ROLES AND RESPONSIBILITIES INSTITUTIONS
Any institution, company or organisation that carries out genetic manipulation, imports organisms arising from such work, produces such organisms, or plans to sell or release such organisms into the environment, should abide by all existing legislation and relevant guidelines, especially current GMAC Guidelines.
SCOPE OF GUIDELINES
The scope of the Singapore Biosafety Guidelines for Research on GMOs covers experiments that involve the construction of all biological entities (cells, organisms, prions, viroids or viruses) which have been made by genetic manipulation and are of a novel genotype and which are unlikely to occur naturally or which could cause public health or environmental hazards.
CATEGORY A – EXPERIMENTS REQUIRING IBC APPROVAL AND GMAC NOTIFICATION (REGULATED EXPERIMENTS WITH SIGNIFICANT RISKS)
This category includes experiments which may pose high risks to laboratory workers, the community or the environment. This category also includes experiments for which the type or level of hazard is unclear. The level of containment required will vary depending on the kind of experiments and their
assessed hazard.
This category of work requires IBC assessment and approval, followed by GMAC notification before work begins. Principal investigators should not commence work on proposals assessed as Category A until advised by theIBC, following IBC’s receipt of GMAC acknowledgement of notification.
CATEGORY B – EXPERIMENTS REQUIRING IBC APPROVAL
(NOTIFIABLE EXPERIMENTS WITH LOW RISKS)
This category includes experiments which may pose low-level risks tolaboratory workers, the community or the environment.
IBC assessment is required before work begins on this category of experiments.
Principal investigators should not commence work on proposalsassessed as Category B until specifically advised by the IBC.
CATEGORY C – EXPERIMENTS EXEMPT FROM THE GUIDELINES
(EXPERIMENTS WITH EXTREMELY LOW RISKS)
This category includes experiments which do not pose significant risks to laboratory workers, the community or the environment.
Principal Investigators who are unsure of the categorization of their experimentsare required to seek advice from their respective IBCs.
Monday, July 30, 2007
Thursday, July 19, 2007
ELISA - Enzyme-linked Immunosorbent Assays
ELISA combines the specificity of antibodies with the sensitivity of simple enzyme assaysm by using antibodies or antigens coupled to an easily-assayed enzyme that possesses a high turnover number. ELISA can provide a useful measurement of antigen or antibody concentration.
Then the reaction is detected by colour change or flourometric reaction that can be measured quantitatively.
There are two types of ELISA developed for detection of mycotoxins.
Direct competitive ELISA and Indirect competitive ELISA.
Direct competitive ELISA involve incubation of a toxin-enzyme conjugated and the unknown sample in the presence of the antibody, typically coated in wells of a microtiter plate or other solid support. Toxin in the sample and the toxin-enzyme conjugate compete for antibody binding sites during incubation and then the solution is washed away. An appropriate substate solution is added to react with any enzyme that is bound by the antibody. The color produced by this reaction can be measure visually by comparison with standards or with a spectrophotometer to acheive quantitation.
Indirect competitive ELISA which uses a mycotoxin-protein conjugate coated on the microplate is incubated with the particular antibody and the test sample. The toxin in the sample competes with the toxin-protein conjugate on the support for antibody binding sites present in the solution. The amount of antibody bound to the plate is determined by reaction with an enzyme complex and subsequently with a substrate.
Then the reaction is detected by colour change or flourometric reaction that can be measured quantitatively.
There are two types of ELISA developed for detection of mycotoxins.
Direct competitive ELISA and Indirect competitive ELISA.
Direct competitive ELISA involve incubation of a toxin-enzyme conjugated and the unknown sample in the presence of the antibody, typically coated in wells of a microtiter plate or other solid support. Toxin in the sample and the toxin-enzyme conjugate compete for antibody binding sites during incubation and then the solution is washed away. An appropriate substate solution is added to react with any enzyme that is bound by the antibody. The color produced by this reaction can be measure visually by comparison with standards or with a spectrophotometer to acheive quantitation.
Indirect competitive ELISA which uses a mycotoxin-protein conjugate coated on the microplate is incubated with the particular antibody and the test sample. The toxin in the sample competes with the toxin-protein conjugate on the support for antibody binding sites present in the solution. The amount of antibody bound to the plate is determined by reaction with an enzyme complex and subsequently with a substrate.
Tuesday, July 17, 2007
Detection of toxins
Most methods designed to provide accurate quantitation rely on a chromatographic separation followed by detection of the mycotoxins. Thin layer chromatography (TLC), High performance liquid chromatography (HPLC) and Gas Chromatography (GC) are the most commonly used methods for accurate quantitation.
Thin Layer Chromatography (TLC)
Microliter quantities of clean-up extract and standards are applied in a horizontal line near one edge of plate. This edge of the plate is placed in a tank containing an appropriate solvent system, which migrates through the sorbent layer, separating the components of the sample.
Mycotoxins are usually visualized as fluorescent spots under UV light, or plates can be sprayed with or exposed to various reagents to effect a chemical change in the mycotoxin that makes it visible. Quantitation is achieved by comparision of the intensity of the fluorescence or color of the sample spot with those of a series of standards.
High Performance Liquid Chromatography (HPLC)
HPLC is similar to TLC except that it differs in the the high efficiency sorbent is packed into a column and the solvent is pushed through with a high pressure pump.
After mycotoxins elute from the column, they immediately pass into a detector which usually measures fluorescence or absorbance of the mycotoxin. This can be compared with similar measurement of known concentration of standards to produce accurate quantitation.
Gas Chromatography
Gas chromatography are best choice for detection of trichothecenes.
When a gas chromatography is coupled with a mass spectrometer (GC-MS), the most reliable identification of GC peaks can be achieved. This method can be used to separate and identify complex mixture of trichothecenes with high sensitivity and selectivity.
Thin Layer Chromatography (TLC)
Microliter quantities of clean-up extract and standards are applied in a horizontal line near one edge of plate. This edge of the plate is placed in a tank containing an appropriate solvent system, which migrates through the sorbent layer, separating the components of the sample.
Mycotoxins are usually visualized as fluorescent spots under UV light, or plates can be sprayed with or exposed to various reagents to effect a chemical change in the mycotoxin that makes it visible. Quantitation is achieved by comparision of the intensity of the fluorescence or color of the sample spot with those of a series of standards.
High Performance Liquid Chromatography (HPLC)
HPLC is similar to TLC except that it differs in the the high efficiency sorbent is packed into a column and the solvent is pushed through with a high pressure pump.
After mycotoxins elute from the column, they immediately pass into a detector which usually measures fluorescence or absorbance of the mycotoxin. This can be compared with similar measurement of known concentration of standards to produce accurate quantitation.
Gas Chromatography
Gas chromatography are best choice for detection of trichothecenes.
When a gas chromatography is coupled with a mass spectrometer (GC-MS), the most reliable identification of GC peaks can be achieved. This method can be used to separate and identify complex mixture of trichothecenes with high sensitivity and selectivity.
Monday, July 16, 2007
Rapid determination of Metallic contaminants
Most metals exhibits their toxic effects in the trace range. Metallic contaminants even in low concentrations can be determined quickly using methods of atmoic spectrometry.
-Atomic Absorption Spectroscopy
It is for detection of cationic (metals) hazards. It involves use of lamp (hollow cathode lamp) that emits electromagnetic radiation of a specific wavelength. Cationic hazards will absorb radiation resulting in their detection.
( A voltage is applied to the electrode sufficient to ionize the neon and the resulting cations are accelerated towards the cathode where it dislodge some of the metal atoms comprising the cathode surface producing an atom "cloud". This process is called sputtering.
-Inductively COupled Plasma Emission Spectroscopy (ICP-AES)
In plasma emission spectroscopy, a sample solution is introduced into the core of an inductively coupled argon plasma(ICP) at a temperature of 8000*C. At this temperature, all elements become thermally excited and emit light at their characteristic wavelengths. This light is collected by the spectrometer and passes through a diffraction grating that serves to resolve the light into a spectrum of its constituent wavelength.
Within the spectrometer, this diffracted light is then collected by wavelength and amplified to yield an intensity measurement that can be converted to an elemental concentration by comparison with calibration standards. This measurement process is a form of atomic emission spectroscopy.
-Atomic Absorption Spectroscopy
It is for detection of cationic (metals) hazards. It involves use of lamp (hollow cathode lamp) that emits electromagnetic radiation of a specific wavelength. Cationic hazards will absorb radiation resulting in their detection.
( A voltage is applied to the electrode sufficient to ionize the neon and the resulting cations are accelerated towards the cathode where it dislodge some of the metal atoms comprising the cathode surface producing an atom "cloud". This process is called sputtering.
-Inductively COupled Plasma Emission Spectroscopy (ICP-AES)
In plasma emission spectroscopy, a sample solution is introduced into the core of an inductively coupled argon plasma(ICP) at a temperature of 8000*C. At this temperature, all elements become thermally excited and emit light at their characteristic wavelengths. This light is collected by the spectrometer and passes through a diffraction grating that serves to resolve the light into a spectrum of its constituent wavelength.
Within the spectrometer, this diffracted light is then collected by wavelength and amplified to yield an intensity measurement that can be converted to an elemental concentration by comparison with calibration standards. This measurement process is a form of atomic emission spectroscopy.
Electrophoresis
Electrophoresis through agarose is a standard method used to separate, identify and purify DNA fragments. The method is simple and rapid to do and capable of resolving fragments of DNA that cannot be separated adequately by other procedures.
Gel electrophoresis is a technique used for the separation of nucleic acids and proteins. Separation of macromolecules depends upon two variables: charge and mass. When a biological sample such as DNA is mixed in a buffer solution and applied to a gel, these two variables act together. The electric current from one electrode repels the molecules while the other electrode simultaneously attracts the molecules. The friction force of the gel material acts as a molecular sieve, separating the molecules by size.
During electrophoresis, macromolecules are forced to move through the pores and their rate of migration through the electric field depedns on the following:
-strength of the field
-size and shape of the molecules
-relative hydrophobicity of the samples
- ionic strength and temperature of the buffer in which the molecules are moving.
Gel electrophoresis is a technique used for the separation of nucleic acids and proteins. Separation of macromolecules depends upon two variables: charge and mass. When a biological sample such as DNA is mixed in a buffer solution and applied to a gel, these two variables act together. The electric current from one electrode repels the molecules while the other electrode simultaneously attracts the molecules. The friction force of the gel material acts as a molecular sieve, separating the molecules by size.
During electrophoresis, macromolecules are forced to move through the pores and their rate of migration through the electric field depedns on the following:
-strength of the field
-size and shape of the molecules
-relative hydrophobicity of the samples
- ionic strength and temperature of the buffer in which the molecules are moving.
Sunday, July 15, 2007
Method to detect GM food - PCR
The most common type of method to detect GM food is PCR - Polymerase Chain Reaction
The Polymerase Chain Reaction is an in vitro technique used to enzymatically amplify a specific DNA region that lies between two regions of known DNA sequence.
Even a single gene copy can be amplified to a million copies within a few hours using PCR.
There are 3 steps in PCR:
-First, the target genetic material must be denatured, the strands of its helix must be unwound and separately by heating to 90 - 96*C.
-The hybridization or annealing where the primers bind to their complementary bases on the now single stranded DNA
-Then the extension of the DNA chain by nucleotide addition from the primers using DNA polymerase as catalyst in the presence of Mg2+.
The Polymerase Chain Reaction is an in vitro technique used to enzymatically amplify a specific DNA region that lies between two regions of known DNA sequence.
Even a single gene copy can be amplified to a million copies within a few hours using PCR.
There are 3 steps in PCR:
-First, the target genetic material must be denatured, the strands of its helix must be unwound and separately by heating to 90 - 96*C.
-The hybridization or annealing where the primers bind to their complementary bases on the now single stranded DNA
-Then the extension of the DNA chain by nucleotide addition from the primers using DNA polymerase as catalyst in the presence of Mg2+.
Monday, July 2, 2007
Customer's rights to GM foods
Genetically modified food (GMF) has caused significant controversy, particularly on issues relating to human safety, consumer information requirements, ethics and the environment.
There are four internationally recognised consumer rights; the right to safety; the right to
know; the right to be heard, and; the right to choose.
Relevance Of The Four Consumer Rights To Marketing And Gmf
There are four globally recognized consumer rights; the right to safety; the right to know; the right to be heard, and; the right to choose.
Right to Safety
Provide consumers with the right to protect themselves against the marketing of products that may be harmful or hazardous to human life and to the environment
Right to Know
Emphasizes the consumers’ access to full information about all products offered for sale in market need in making informed decisions.
Right to be Hear
Implies that consumer dissatisfaction with and concern about the consumption and use of products and services to be heard and addressed by the marketer.
Right to Choose
Implies that consumers to be provided with the opportunity to select their desired food items from amongst a number of alternatives so that the customers will buy and consume the right GMF of their choice.
There are four internationally recognised consumer rights; the right to safety; the right to
know; the right to be heard, and; the right to choose.
Relevance Of The Four Consumer Rights To Marketing And Gmf
There are four globally recognized consumer rights; the right to safety; the right to know; the right to be heard, and; the right to choose.
Right to Safety
Provide consumers with the right to protect themselves against the marketing of products that may be harmful or hazardous to human life and to the environment
Right to Know
Emphasizes the consumers’ access to full information about all products offered for sale in market need in making informed decisions.
Right to be Hear
Implies that consumer dissatisfaction with and concern about the consumption and use of products and services to be heard and addressed by the marketer.
Right to Choose
Implies that consumers to be provided with the opportunity to select their desired food items from amongst a number of alternatives so that the customers will buy and consume the right GMF of their choice.
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