IMMUNITY ,
INFECTION AND
FORENSICS
, time of death succession
Determining
ways to determine how long body has been dead for :
> lan
-
idently Top from particular stage of succession body's in
.
- 9
1) Body temp > beetles etc.
. When corpse 11 shil fresh and war m bacteria >
-
larvae -
( > 24hrs)
2) Rigor morris >
-
similar to plant succession . BUT most early insects will remain on the body as other insects colonise it
3) signs of decomposition >
-
Location of body may afrect stage or succession ("above ground, under ground , in water ,
sealed away
when corpse is decomposing
ANA profilinto
4) Forensic entomology ( < 24hrs)
5) Stage of succession idently people and to determine generic relahonships between humans ,
animal plant i s
Algor Morris (Body temp . summary
normal human body temp: 36 2 to 37 6 % 1) Tissue sample obtained and Dra extracted
-
range of . .
I measure cove body temp .
Using a long , electronic temp. probe via the rechum or through an abdominal stab 2 DNA cut into fragments using endonucleases
heat metabolic reachons (es respiranon) DNA is replicated there is analysis (OCR)
>
-
Body produces from 3 so enough for
-> After death , body temp .
begins to cool due to the reduction of metabolism -
normal body temp. is 4
Fragments are separated using get electrophoresis
reduces the prk profile
maintained by blood circulation But heart stops so circulation 5) Fragments are visualised using southern blotting to create
=> will continue coolingfill temp equals .
surroundings Cambient temp )
.
6) DNA profile is compared to reference profile
>
-
body cool at a rate of 1 5%
. to 20 per hour Obtaining DNA sample
>
-
algor morts : post-mortem cooling of the body based on a signold curve
(cooling curve) ASSUMING
sample of DNA
Is Obtained from Organism the DNA profile is being made for 19 from blood saliva
,
etc.
inital body temp was 37 % > Obtain DNA sample from non-coding region
-
,
>
-
factors affecting cooling rate :
body size/position, clothing , air movement , humidity >
-
Breakdown issue sample in butter solution (includes salt + detergent) to disrupt cell membrane
e .
9 .
18 body is in water
,
it will cool quicker as water is a better conductor of heat than air >
-
suspended paracles (Includes DNA) are separated by filtering or centrifuging
9 proteins to precipitate DNA
e . .
is person has fever or hypothermia, body temp. at point of death will be elevated depressed >
-
use protease to remove + ethanol
Rigor Morns
DNA structure
>
-
refers to the degree or muscle contraction + suffness >
-
exons =
coding regions, vanable
1) After death, muscle cells become deprived of oxygen and oxygen dependent reachons stop > introns
-
=
non-coding regions hypervanable (vanahon between no .
of repeal of STRs)
,
2) Respiration in the cells becomes anaerobic and produces lactic add = STRs (short tandem repears) = sequences of repeated bases found in inwons (also known al satellites
3) cell falls inhibiting enzymes => mini-satellites DNA sequence usually of 20-50 base pairs that are repeated between 50 and several 100 times
pH of the inhibiting
thus anderobic :
,
and respiration
needed proteins => micro-satellites Short DNA sequences usually of 2-4 base pairs that are repeated between 5 to 15 times
longer produced
:
4) The ATP for muscle contraction is no : bonds between muscle
Imyosin +actin) become fixed and the body stiffens
·
STRs are usewl for forensic scientish as the number of STR repeats at each locus differs amongst undividuals
it is highly unlikely for individuals to have the combination
5) The proteins can no longer more over e/o to shorten the muscle , fixing the muscle and joints
- 2
of STR repeats at several different loci
recognihonsequence (SAME)
>
-
Calcium cons are also released from sarcoplasmic reculum , combrhing to shotening of muscles
> smaller
-
muscles (2 % in the head) shofen cust then larger muscles (19in lower body) shchen last
> most bodies
- complete rigor mort's between 6 and 9 hours
>
-
RM actected by degree of muscle development + temp . 199RM occurs laster at higher temps be STR (different
chemical reactions in the body are caster)
Decompositon ·
in homologous chromosomes, the same satellites occur at the same locus on both chromosomes of a homo-
-
>
-
the break down of dead organic matter by decomposers which use the organic molecules for logous pair BUT the number of STR repeats on each homologue vares
-
respiration crearing fragments
+ decomposen will release digestre enzymes Isoluble molecules) > use
-
resuchon enzymes to create fragment of DNA
Autolysis
=> will only cut up DNA ar specific base sequences : can splice our introns (STR sequences) for analysis
from the digestive break down cells
>
-
body's own enzymes , tract and from lysosomes
>
-
bacteria from the gut + galeous exchange system invade issues after dearn , releasing enzymes
that result in decomposition .
> loss
-
of O in ussues favours growth of anderobic bacteria > has It bonds > I bonds join
, - -
together
of decomposition a exposed
Extent
> uniform
-
>
-
non-uniform
>
-
first 48 his after death
cells and
enzymes and bacteria present before
> tissues are broken down by body's death
-
own
>
-
autolysis starts
PCR (polymerase chain reaction
>
-
skin turns to greenish colour (discolouration of abdominal wall DNA is amplified/replicated to ensure PNA
profiling is effective
Bloated 1) sample cell is wealed (w/ detergent) to release DNA
>
-
48hrs to I week after death 2) prA polymerase, DNA phmen (w/ fluorescent markers) and cree nucleoudes are added
% is heated to separate
organs (fermentation)
and 3 95 sample DNA swand ,
>
-
microorganisms decompose tissues At
>
-
produces gases !"methane ,
hydrogen sulphide etc. ) which causes body to become bloated (putrefaction) >
-
95 %= to break hydrogen bonds between DWA stands
omenwnvaspetimommenteena
>
-
Formation of sulthaemoglobin in blood skin turning blue-black colour
>
-
skin begins to blister and fall off
-
Active Decay
% ophmum temperature for DNA polymerase
days after death
> 4-10
- > 70
- =
> Tissues
-
begin to liguity and seep out into the area around the body 6) Cycle is repeated several times to make several copies of DNA
waxy substance
fatty acids turned to a
>
-
* DNA polymerase is different
to other enzymes be it Is THERMO-STABLE - doesn't denature at 4 temp.s
> gas
-
released + body deflates Gel Electrophoresis
>
-
MAGGOTS Usually found ·
used to separate DNA
Advanced decay 1) DNA is placed into a well in a slab of get and covered in a buffer solution that conduct electricity
> 10.20
-
days after death 2) An electical current is passed through the gel-PNA fragments are negatively charged ,
so they move
Hegoneonly Skeletoremanseed
towards the anode at far end of get
ladipocere -
grave wax
more faster + travel further through the gel the DWA fragments separate
3 Short DNA fragments ,
so
Dry according to length
+ 50 +
days after death 1) Gel is viewed under uV light
-
DNA fragments appear as bands
remain
> Skeleton
-
begins to disintegrate -
only hair + some bones 5) two DNA profiles can be compared to see how similar the pattern of the bands on the gel is -
a
Forensic Entomology
> can
-
idently type of insectfound on body
> can
-
use insect to idently stage of life cycle insect is in 199 eggs = less than 24
horn)
insect's (e 9 drugs temp )
=> different conditions affect life Cycle humidity 0
.
+
.
can an , ,
!
= Caster metabolic rate + shorter life cycle
=> ↑ temp .
INFECTION AND
FORENSICS
, time of death succession
Determining
ways to determine how long body has been dead for :
> lan
-
idently Top from particular stage of succession body's in
.
- 9
1) Body temp > beetles etc.
. When corpse 11 shil fresh and war m bacteria >
-
larvae -
( > 24hrs)
2) Rigor morris >
-
similar to plant succession . BUT most early insects will remain on the body as other insects colonise it
3) signs of decomposition >
-
Location of body may afrect stage or succession ("above ground, under ground , in water ,
sealed away
when corpse is decomposing
ANA profilinto
4) Forensic entomology ( < 24hrs)
5) Stage of succession idently people and to determine generic relahonships between humans ,
animal plant i s
Algor Morris (Body temp . summary
normal human body temp: 36 2 to 37 6 % 1) Tissue sample obtained and Dra extracted
-
range of . .
I measure cove body temp .
Using a long , electronic temp. probe via the rechum or through an abdominal stab 2 DNA cut into fragments using endonucleases
heat metabolic reachons (es respiranon) DNA is replicated there is analysis (OCR)
>
-
Body produces from 3 so enough for
-> After death , body temp .
begins to cool due to the reduction of metabolism -
normal body temp. is 4
Fragments are separated using get electrophoresis
reduces the prk profile
maintained by blood circulation But heart stops so circulation 5) Fragments are visualised using southern blotting to create
=> will continue coolingfill temp equals .
surroundings Cambient temp )
.
6) DNA profile is compared to reference profile
>
-
body cool at a rate of 1 5%
. to 20 per hour Obtaining DNA sample
>
-
algor morts : post-mortem cooling of the body based on a signold curve
(cooling curve) ASSUMING
sample of DNA
Is Obtained from Organism the DNA profile is being made for 19 from blood saliva
,
etc.
inital body temp was 37 % > Obtain DNA sample from non-coding region
-
,
>
-
factors affecting cooling rate :
body size/position, clothing , air movement , humidity >
-
Breakdown issue sample in butter solution (includes salt + detergent) to disrupt cell membrane
e .
9 .
18 body is in water
,
it will cool quicker as water is a better conductor of heat than air >
-
suspended paracles (Includes DNA) are separated by filtering or centrifuging
9 proteins to precipitate DNA
e . .
is person has fever or hypothermia, body temp. at point of death will be elevated depressed >
-
use protease to remove + ethanol
Rigor Morns
DNA structure
>
-
refers to the degree or muscle contraction + suffness >
-
exons =
coding regions, vanable
1) After death, muscle cells become deprived of oxygen and oxygen dependent reachons stop > introns
-
=
non-coding regions hypervanable (vanahon between no .
of repeal of STRs)
,
2) Respiration in the cells becomes anaerobic and produces lactic add = STRs (short tandem repears) = sequences of repeated bases found in inwons (also known al satellites
3) cell falls inhibiting enzymes => mini-satellites DNA sequence usually of 20-50 base pairs that are repeated between 50 and several 100 times
pH of the inhibiting
thus anderobic :
,
and respiration
needed proteins => micro-satellites Short DNA sequences usually of 2-4 base pairs that are repeated between 5 to 15 times
longer produced
:
4) The ATP for muscle contraction is no : bonds between muscle
Imyosin +actin) become fixed and the body stiffens
·
STRs are usewl for forensic scientish as the number of STR repeats at each locus differs amongst undividuals
it is highly unlikely for individuals to have the combination
5) The proteins can no longer more over e/o to shorten the muscle , fixing the muscle and joints
- 2
of STR repeats at several different loci
recognihonsequence (SAME)
>
-
Calcium cons are also released from sarcoplasmic reculum , combrhing to shotening of muscles
> smaller
-
muscles (2 % in the head) shofen cust then larger muscles (19in lower body) shchen last
> most bodies
- complete rigor mort's between 6 and 9 hours
>
-
RM actected by degree of muscle development + temp . 199RM occurs laster at higher temps be STR (different
chemical reactions in the body are caster)
Decompositon ·
in homologous chromosomes, the same satellites occur at the same locus on both chromosomes of a homo-
-
>
-
the break down of dead organic matter by decomposers which use the organic molecules for logous pair BUT the number of STR repeats on each homologue vares
-
respiration crearing fragments
+ decomposen will release digestre enzymes Isoluble molecules) > use
-
resuchon enzymes to create fragment of DNA
Autolysis
=> will only cut up DNA ar specific base sequences : can splice our introns (STR sequences) for analysis
from the digestive break down cells
>
-
body's own enzymes , tract and from lysosomes
>
-
bacteria from the gut + galeous exchange system invade issues after dearn , releasing enzymes
that result in decomposition .
> loss
-
of O in ussues favours growth of anderobic bacteria > has It bonds > I bonds join
, - -
together
of decomposition a exposed
Extent
> uniform
-
>
-
non-uniform
>
-
first 48 his after death
cells and
enzymes and bacteria present before
> tissues are broken down by body's death
-
own
>
-
autolysis starts
PCR (polymerase chain reaction
>
-
skin turns to greenish colour (discolouration of abdominal wall DNA is amplified/replicated to ensure PNA
profiling is effective
Bloated 1) sample cell is wealed (w/ detergent) to release DNA
>
-
48hrs to I week after death 2) prA polymerase, DNA phmen (w/ fluorescent markers) and cree nucleoudes are added
% is heated to separate
organs (fermentation)
and 3 95 sample DNA swand ,
>
-
microorganisms decompose tissues At
>
-
produces gases !"methane ,
hydrogen sulphide etc. ) which causes body to become bloated (putrefaction) >
-
95 %= to break hydrogen bonds between DWA stands
omenwnvaspetimommenteena
>
-
Formation of sulthaemoglobin in blood skin turning blue-black colour
>
-
skin begins to blister and fall off
-
Active Decay
% ophmum temperature for DNA polymerase
days after death
> 4-10
- > 70
- =
> Tissues
-
begin to liguity and seep out into the area around the body 6) Cycle is repeated several times to make several copies of DNA
waxy substance
fatty acids turned to a
>
-
* DNA polymerase is different
to other enzymes be it Is THERMO-STABLE - doesn't denature at 4 temp.s
> gas
-
released + body deflates Gel Electrophoresis
>
-
MAGGOTS Usually found ·
used to separate DNA
Advanced decay 1) DNA is placed into a well in a slab of get and covered in a buffer solution that conduct electricity
> 10.20
-
days after death 2) An electical current is passed through the gel-PNA fragments are negatively charged ,
so they move
Hegoneonly Skeletoremanseed
towards the anode at far end of get
ladipocere -
grave wax
more faster + travel further through the gel the DWA fragments separate
3 Short DNA fragments ,
so
Dry according to length
+ 50 +
days after death 1) Gel is viewed under uV light
-
DNA fragments appear as bands
remain
> Skeleton
-
begins to disintegrate -
only hair + some bones 5) two DNA profiles can be compared to see how similar the pattern of the bands on the gel is -
a
Forensic Entomology
> can
-
idently type of insectfound on body
> can
-
use insect to idently stage of life cycle insect is in 199 eggs = less than 24
horn)
insect's (e 9 drugs temp )
=> different conditions affect life Cycle humidity 0
.
+
.
can an , ,
!
= Caster metabolic rate + shorter life cycle
=> ↑ temp .
