Chapter 11: Serology Techniques: Past, Current, and Future

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58 Terms

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Forensic serology
is the component of forensic biology that deals with the examination and identification of biological evidence.
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Short Tandem Repeats (STR)
The most commonly utilized forensic DNA analysis used for human identification.
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Y-chromosomal STR analysis
is often utilized for the investigation of sexual assault crimes.
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Mitochondrial DNA analysis
is used for the identification of human remains.
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presumptive and confirmatory assays
The identification of bodily fluids can be carried out using ______ to identify the type of bodily fluid in question.
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Positive assay
indicates the possibility of the presence of the bodily fluid in question.
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Negative assay
indicates that the questioned bodily fluid is absent.
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Confirmatory Assays
These assays are utilized to identify bodily fluids with higher certainty than presumptive assays.
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Primary Binding Assays
It involves the initial binding between a single epitope of an antigen and a single binding site of an antibody. They are very sensitive.
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Secondary Binding Assays
They are less sensitive and easier to perform than primary binding assays.
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Precipitation-based assays
________ have been used for species identification.
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Agglutination-based assays
______ are more sensitive. It detects antigens located on the surface of cells or carriers, are normally applied to blood group typing.
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Enzyme-Linked Immunosorbent Assay (ELISA)
It is an immuno-enzyme assay that can be used to detect and measure the antibody or antigen in question.
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Antibody-sandwich ELISA
The most common ELISA that is used in forensic serology.
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Immunodiffusion
A passive method in which an antigen or an antibody or both are allowed to diffuse and therefore a gradient, from low to high concentration, is established for an antigen or an antibody or both.
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Single Immunodiffusion
A concentration gradient is established for either an antigen or an antibody.
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Double Immunodiffusion
A concentration gradient is established for both an antigen and an antibody.
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Immunoelectrophoresis (IEP)
This technique uses electrophoresis to separate the antigen mixture prior to immunodiffusion.
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Crossed Immunoelectrophoresis
Also known as two-dimensional IEP, is a modification of IEP.
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Rocket Immunoelectrophoresis
An antibody-containing agarose gel is used. The antigen is loaded into the well.
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Crossed-Over Immunoelectrophoresis
This technique is also known as counterimmunoelectrophoresis (CIE).
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Agglutination reactions
can be used as forensic serological assays such as for blood group typing and menstrual blood identification.
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Agglutination assays
are qualitative, indicating the absence or presence of antigens or antibodies.
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Semi-quantitative assays
results can be obtained by titration.
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Direct agglutination assays
involve reactions in which an antibody interacts with antigens originally located on cell surfaces.
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hemagglutination reaction
In a ______, an antibody binds to the antigens located on erythrocytes.
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Agglutination inhibition assays
The presence of an antigen in question is indirectly detected.
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Passive agglutination assays
The antigen is coated on the surface of carrier cells such as tannic acid–treated sheep erythrocytes.
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CpG dinucleotide sequences
In the eukaryotic genome, methylation occurs at the cytosine residues commonly in the _________ of both DNA strands.
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phosphodiester
The “p” in CpG refers to the _______ bond between cytosine and guanine.
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Cytosine methylation
is carried out in vivo by methyltransferase.
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Genomic Loci
Also known as tissue-specific differentially methylated regions (TDMRs).
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Methylation-sensitive restriction enzyme digestion polymerase chain reaction (MSRE-PCR)
can be used for the rapid detection of DNA methylation.
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Bisulfite sequencing
The genomic DNA is treated with sodium bisulfite, which catalyzes the hydrolytic deamination of unmethylated cytosines.
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Methyl-DNA immunoprecipitation (MeDIP)
is a useful method for isolating methylated DNA.
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Messenger RNA-Based Assays
can potentially be used for wound age estimation and the age of biological stains.
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Reference genes
Are constitutively expressed housekeeping genes are utilized as internal controls.
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MicroRNA-Based Assays
The biological function of microRNAs (miRNAs) is to regulate gene expression.
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Mass spectrometry (MS)
is a susceptible and rapid technique for protein identification from complex biological samples.
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Mass spectrometer
An analytical technique to identify a molecule by measuring the ratio of the mass (m) to the charge (z) of a charged molecule.
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Ion source
Converts analytes into gaseous phase ions through ionization.
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Ionization
A process used by gaining a positive or a negative charge from a neutral species.
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Mass Analyzer
A part of a mass spectrometer where ions are accelerated under electric fields and separated based on their m/z ratio.
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Biomarker proteins
can be identified by peptide sequencing using the tandem mass spectrometry (MS/MS) mode of operation in which a mass spectrometer uses two or more mass analyzers.
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precursor ions
After an initial mass analysis, individual peptide ions in the mass spectrum can be selected. The selected ions are known as ________.
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product ions
A precursor ion is then subjected to the second round of fragmentation through collision and is broken into smaller ions known as _______.
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top-down strategy
In ________, intact proteins in a complex mixture are fractionated and separated into less complex protein mixtures or single proteins.
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bottom-up strategy
The ________ is commonly used for high-throughput analysis of small peptides derived from highly complex samples.
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Sort-then-break approach
Proteins in a complex mixture are first isolated and then enzymatically cleaved.
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Break-then-sort approach
Also known as the shotgun approach, wherein proteins are cleaved first and the resulting peptide mixture is then separated by LC and analyzed by tandem MS.
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Human Microbiota
Microbial community.
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Metagenomics
Allows the study of the microbial genome of complete microbial communities harvested directly from natural environments.
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5S and 23S rRNA genes
encode the RNA components of the large subunit of the ribosome.
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16S rRNA gene
encodes the RNA component of the small subunit of the ribosome.
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intergenic spacer region (ISR)
The _______ between the 16S rRNA and 23S rRNA genes in the rRNA operon is another commonly used marker.
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Fluorescence
The emission of light by a fluorophore.
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Fluorophore
A moiety in a molecule that fluoresces on absorbing the energy from an excitation light source or radiation.
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Raman spectroscopy
Utilizes a near-infrared excitation light source and measures the scattering of laser light caused by the vibrating molecules of a sample.