Module 13.3

Question 1

Human semen

Answer 1

Organic fluid, may contain sperm
Multiple components, multiple organs:
-testes-sperm
-vesicular gland-amino acids, semenogelin, citrate, flavins
-prostate-prostatic acid phosphatase, citric acid, fibrinolysin, prostate specific antigen
-bulbourethral glands-galactose, mucus

Question 2

Sperm detection

Answer 2

May be present in ASA cases
Absent? Lack of ejaculation, condom, aspermia, drainage, not male perp, no penile penetration

Question 3

Tests for semen ID

Answer 3

Screening: Y/N, acid phosphatase, assay for prostate specific antigen, semenogelin, mass spec proteomics
Confirmatory: microscope ID, analysis of Y-STR, mass spec proteomics

Question 4

Canine vs human sperm

Answer 4

Canine
-size/shape: head 7x4 um, dimple on head
-christmas tree stain-acrosomal cap: pale red, postacrosomal region: red, colorless band b/w
Human
-size/shape: head 4.6x2.6 um
-christmas tree stain: postacrosomal region: dk red

Question 5

Semenogelin protein

Answer 5

W/in seminal vesicle
2: I and II (SgI/SgII)-non-glycossylated protein
Interact noncovalently by disulphide bridges to form coagulum-inhibits sperm motility, PSA cleaves Sg

Question 6

Cross-reactivity findings

Answer 6

Canin samples: all - for Sg: semen, blood, saliva, vag, urine; 1 false +: rectal
Allowed for successful ID of human semen in mixed samples
Lack of cross-reactivity in other species