Forensic Biology Final

Acid phosphatase is an enzyme that is active at a pH above 7. T/F

False. It is active at acid pH.

What is the average acid phosphatase concentration found in human seminal fluid in king-armstrong units/100mL semen?

370,000

In the p30 antigen, what does the p refer to and what does the 30 refer to?

P refers to prostate and 30 refers to the molecular weight of the glycoprotein of 30,000 daltons

High dose hook effect is caused by the presence of small amount of antigens. T/F

False

What is an alternate light source (ALS) and what is it used for?

A special blue light and orange filters. It is a presumptive test for the identification of seminal material.

When an ALS is used in a piece of evidence, only the semen will fluoresce. T/F

False. Saliva, semen, and urine can all fluoresce under the ALS.

To what society did Leeuwenhoek present his findings on spermatozoa?

Philosophical Transactions of the Royal Society of London

What are the five things Leeuwenhoek explained in his speech regarding the discovery of spermatozoa?

Bodies were round, blunt in the front, and ran to a point behind.
Furnished with a thin tail, 5 or 6 times as long as the body.
Moved like a snake or eel.
Smaller than the corpuscles.
In a thicker substance, they had to lash their tails more to move.

The enzyme acid phosphatase is found in approximately how many times more in semen compared to other body fluids?

400 times more

What can Acid Phosphatase also be called?

Prostate phosphatase

Acid phosphatase is highly stable at 37C. T/F

False

In some instances, it is possible to get a positive AP test result and negative sperm search. T/F

True

What are the two reasons that one might get a positive AP test result and a negative sperm search?

If the sample came from an oligospermic or aspermic individual.

What is azoospermic?

The complete absence of sperm in the semen. Man is completely infertile. This diagnosis can be made even if 500,000 sperm or less are present.

What is the total length of a human spermatozoon?

55 micron

What does PSA stand for?

Prostate Specific Antigen

What are the spermatozoa parts and measurements?

Head, midpiece, acrosome, nucleus, tail
Total length is 55 micron, head length is 4.6 micron, head width is 2.5 micron, and head thickness is 1.5 micron

How is the problem of the high dose hook effect corrected in the PSA identification test?

The sample is diluted

A large piece of evidence such as bed sheets are examined first by acid phosphatase test before other methods are employed. T/F

False. An ALS is used first to identify if any areas fluoresce.

What is the process of screening large pieces of evidence, such as underwear, for the presence of seminal fluid commonly called?

AP mapping test, or press test

Who is Leeuwenhoek and what did he do in 1677?

Dutch scientist that is known as the father of micrometry. He was the first to identify spermatozoa under the microscope.

List any ten items of evidence that are collected during a sexual assault examination.

Fingernail scrapings
Urine specimen
Sheets/bedding from scene
Head hairs
Pubic hairs
Blood sample
Buccal swabs
Clothing worn at the time of the assault
Clothing worn at the time of the exam
Vaginal/Penile swabs

What are the three presumptive tests that can be used to detect the presence of seminal fluid?

Acid Phosphatase, Barberios crystal test, and Florence crystal test

What is the name of the purple color compound identified in the AP spot test?

Alpha naphthyl phosphate

What is AP mapping (press test)?

It is the test used to test a large area or piece of evidence for the evidence of acid pohsphatase.

What is the normal sperm count expected in humans?

20 million to 120 million

What is oligospermic?

Sperm cells are produced but are very low. Less than 20 million sperm cells/mL in the ejaculate.

What is aspermic?

Absence of any ejaculate (semen)

What are the three tests that can be used for seminal fluid/semen identification?

Observation of spermatozoa; ABA card p30 test strip; Ouchterlony double immunodiffusion

What are the two stains used in the staining of spermatozoa?

Nuclear fast red and picro indigo carmine (green)

What part of the spermatozoa provides protection to the sperm head?

Acrosome

What is the purpose of the mitochondria in a spermatozoa?

Regulate levels of important intracellular second messengers; also in charge of apoptosis

What are the two key characteristics used in the identification of spermatozoa using a microscope?

Tail and differential stained head

What are the number of chromosomes present in a spermatozoon?

23 chromosomes

What is the anterior opaque part of the spermatozoon head called?

Acrosome

Where are the mitochondria located in a spermatozoa?

Middle piece

What is the length of the head of the human spermatozoon?

4.6 micron

The concentration of PSA in blood is usually at or below what in normal males?

4.0 ng/mL

What is the composition of Florence crystal test reagent?

Potassium iodide, iodine, and diH2O

What is Ouchterlony double immunodiffusion?

Two things diffuse - antigen and antibody - for identification of sample

What is a King-Armstrong unit?

The amount of enzyme needed to liberate 1 mg of phenol from phenyl phosphate at 37.5C in 30 mins at pH 9.1

What are the two end products that result in the digestion of Sodium alpha naphthyl phosphate by acid phosphatase?

Stain or stain extract; purple color reaction

What is the molecular weight of the p30 antigen?

30,000 daltons

P30 antigens will react with anti-PSA antibodies. T/F

True

What is the company that manufactures the ABA card one step PSA test kit?

Abacus Diagnostics

What is the principle involved in the ABA card one step test kit for the identification of seminal material?

Antigen-antibody reaction

What are the three antibodies present in the ABA card one step test kit for the identification of seminal material?

Mobile anti-PSA antibody; immobilized anti-PSA antibody; immobilized immunoglobulin antibody

Vasectomized individuals will have normal sperm production. T/F

False

What is high dose hook effect and what happens during this process?

High dose hook effect is what happens when the concentration of the sample is too high and blocks the binding of the antigen/antibody complex to the immobilized antibody

If the test results are AP - negative, Sperm search - negative, and PSA screening - positive, what is your conclusion?

Semen present but cannot be confirmed (MAYBE)

If the test results are AP screening - positive, Sperm search - negative, PSA screening - negative, what is your conclusion?

Semen absent (MAYBE)

The amount of the enzyme amylase is found how many times more in saliva than other body fluids?

50 times

What does the appearance of a blue color indicate the presence of in the saliva test plate using agarose petridishes?

Starch

Higher concentration of amylase indicates the presence of semen. T/F

False

In the salivary amylase test, iodine is used for staining the agarose. T/F

True

What is the significance of the clear area and the blue area in the agarose petri dish test for saliva?

Clear area indicates there is amylase present, as it hydrolyzed the starch.
Blue area indicates there is no amylase present because the starch is still present to be stained.

You are using the following samples and antibodies in an immunodiffusion experiment. Indicate where there would be a precipitin band formation.
1 - center well is anti-PSA antibodies
2 - known human semen
3 - cattle semen
4 - rabbit serum
5 - human blood
6 - known human semen
7 - known human serum

1/2 - precipitin band
1/3 - none
1/4 - none
1/5 - none
1/6 - precipitin band
1/7 - precipitin band