Click to edit Master title style
Trace elements:
As precious as gold for your health
Dominic Hare and Blaine Roberts
UTS Science in Focus Public Lecture
22 August 2012
THINK.CHANGE.DO
First of all, thanks to…
UTS: Centre for Forensic Science
Atoms: Building blocks of the Universe
• The atoms that make up your body, your house, your
brand new car are as old as the universe itself
– 14 or so billion years, give or take a few leap years
• How atoms interact with each other determines how
matter changes
• Consider then, that the atoms in your body have
experienced an eternity of life experiences, sights,
smells, sounds, loves, despairs stretching all the way
back to the birth of the cosmos.
UTS: Centre for Forensic Science
UTS: Centre for Forensic Science
Chemical properties of atoms
• The number of protons determines which element the
atom represents
– Hydrogen has 1, helium has 2, lithium has 3…
• The number of neutrons determines which isotope of
the element it represents
– Isotopes have the same properties, but have a slightly
different mass
• The number of electrons orbiting the nucleus
determines how the atom will react
UTS: Centre for Forensic Science
Electrons and chemical reactions
• How electrons interact with other atoms determines
what state an atom exists in, and how they react
UTS: Centre for Forensic Science
What makes you, you
UTS: Centre for Forensic Science
What about the rest?
• 0.1% sulfur, potassium, sodium and chlorine
• 0.006% iron, or 4.2 grams, equivalent to everyone
here relative to Sydney’s population
• 0.0001% copper, or 0.072 grams, equivalent to a
single grain of rice in 5 buckets of water
• 0.000016% iodine, or 0.02 grams, equivalent to one
minute every 6 years
• 0.0000021% cobalt, or 0.000003 grams, equivalent to
one drop of water in an Olympic-sized swimming pool
UTS: Centre for Forensic Science
So, how can we possibly measure something that
small?
UTS: Centre for Forensic Science
Flame tests
Sodium
Potassium
Copper
UTS: Centre for Forensic Science
Atomic emission
• As the sample heats in the flame, it gets broken down
into it’s constituents
• Electrons moving around the nucleus take in some of
the energy from the flame and jump up to a higher
orbital
• When these electrons lose energy, they drop back
down to their original orbital, emitting light as they go
UTS: Centre for Forensic Science
Atomic emission spectra
Hydrogen
Iron
Mercury
UTS: Centre for Forensic Science
Emission is great, but…
• It often lacks the sensitivity to measure truly trace
amounts of something
• How can we measure atoms directly?
UTS: Centre for Forensic Science
On a lighter note…
• Everything weighs something (or, at least officially
since July 4, 2012)
• Each and every proton and neutron (and even
electron) contributes to an element’s mass
• If phosphorus has 15 protons…
• …and sulfur has 16 protons…
• …an atom of sulfur must weigh
more than an atom of
phosphorus!
UTS: Centre for Forensic Science
The ICP: A super-charged Bunsen burner
UTS: Centre for Forensic Science
The evolution of the ICP-MS
Inductively coupled plasma-mass spectrometers circa 1980s
UTS: Centre for Forensic Science
You were talking about the body…?
• An ICP-MS gives us a technique that is sensitive
enough to be able to measure those minute
differences in trace elements in the body
• Cutting-edge ICP-MS is capable of detecting down to
parts-per-quadrillion, or one centimetre in 50 round
trips to the Sun
UTS: Centre for Forensic Science
Laser ablation
UTS: Centre for Forensic Science
LA-ICP-MS Imaging
UTS: Centre for Forensic Science
Imaging Process
UTS: Centre for Forensic Science
Imaging Process
Mass
Spec
Ion
Detector
Ion
lenses
ICP
Cones
Data
Processing
UTS: Centre for Forensic Science
LA-ICP-MS imaging
• Each image gives us quantitative spatial information
about trace elements, without the need for excision
Iron
1mm
UTS: Centre for Forensic Science
LA-ICP-MS imaging
• We can look at how diseases change trace elements at
the micro-meter scale, in situ.
Iron
1mm
UTS: Centre for Forensic Science
Reconstructing iron in the mouse brain
UTS: Centre for Forensic Science
Three-dimensional imaging
UTS: Centre for Forensic Science
Where are we going now?
UTS: Centre for Forensic Science
Trace elements: As precious as gold for
your health
Dominic Hare and Blaine Roberts
UTS Science in Focus Public Lecture
22 August 2012
Periodic Table
Abundance in the Universe
What are the Biological Elements of Life?
Lipids
Protein
Carbohydrates
DNA
Central Dogma of Biology
Lipids = membranes
Carbohydrates = energy
Proteins = function
Proteins equal Function
“ Pretty much anything a cell does,
a protein does it.”
–P.
Andrew Karplus
3D crystal structure of antioxidant enzyme Cu, Zn
Superoxide Dismutase
Human Genome
-23 chromosomes ~ 22,000 genes
-30-50% of proteins use metal to function
Examples;
Hemoglobin(Fe), Ferritin (Fe), Matrix
metalloprotease (Zn), Xanthine Oxidase (Mo)
….etc.
Vitamin and mineral Supplements
*Daily value not established
We know that many minerals are essential but don’t
know how much, why in most cases.
Diseases caused by mineral
Deficiency
Hemochromotosis
Anemia (Fe, Cu)
Acrodermatitis enteropahtica (Zn)
Menke’s disease
(Cu)
Wilson’s disease (Fe)
Malnutrition
Zinc deficiency one of the most common
deficiencies in the world
Over 2 Billion people are estimated to be
deficient in zinc.
-Decreased wound healing
-Impaired immune function
-Impaired growth and neurological
development
-Aggressive behavior
Alzheimer’s disease
Alois Alzheimer
Auguste Deter
•Although named after Alois the disease was describe previously by
Fischer, Bonfiglio, Perusini.
•Accounts for 50-80% of dementia.
•Average patient lives 8 years but can be up to 20 years.
•Projected cost of $20 Trillion dollars over the next 40 years.
Alzheimer’s Pathology
•Pathology begins 10-15 years before disease
symptoms arise (Braak 1996)
•Disease pathology begins in the neocortex and
and progressively spreads through the cortex.
•Massive neuronal loss >50%.
Amyloid Plaques
Fe, Cu, K, and Rb are altered in AD Brain.
Amyotrophic Lateral Sclerosis
Zinc-deficient SOD hypothesis for ALS
• Zinc deficient SOD hypothesis
– Without zinc, copper is reduced ~3000x faster than Cu,Zn-SOD (Estevez,
AG et al.)
– Many SOD mutants have a reduced affinity for zinc (Crow, JP et al.)
e-
Ascorbate
Cu+2
Cu+2
Purified SOD
Cu+1
Cu+1
O=O
O=O•- + NO•
ONOOApoptosis
Cu,Zn
Zincdeficient
Estevez, A. G., Crow, J. P., Sampson, J. B., Reiter, C., Zhuang, Y., Richardson, G. J., Tarpey, M. M., Barbeito, L. & Beckman, J. S. (1999). Induction
of nitric oxide-dependent apoptosis in motor neurons by zinc-deficient superoxide dismutase. Science 286, 2498-500.
Crow, J. P., Sampson, J. B., Zhuang, Y., Thompson, J. A. & Beckman, J. S. (1997). Decreased zinc affinity of amyotrophic lateral sclerosis-associated
superoxide dismutase mutants leads to enhanced catalysis of tyrosine nitration by peroxynitrite. J Neurochem 69, 1936-44.
Measuring Global Metalloprotein Changes
with Liquid Chromatography-ICPMS
Agilent HPLC 1200
Agilent 7700 ICP-MS
Output
Size exclusion column
(Agilent BioSEC
4.6x300mm)
Vo
Vt
Decreasing MW
Measure Protein Metal Status Directly
Metalloproteomics = measure of metal bound to protein
Thyroglobulin,
660kDa
Thyroglobuli
n
aggregate
Cu,ZnSOD,
32kDa
Ferritin
,
440kD
Conalbumi
a
n,
75kDa
Catalas
e,
256kDa
Vit
B12
V
t
Application of Metalloproteomics
Each island is a
different Zn-Protein
The Zn metalloproteome
Micronutrient Information Center
For more information on minerals and vitamins in health and
disease please visit the Linus Pauling Institute Micronutrient
Information Center. (http://lpi.oregonstate.edu/)
Summary
-Proteins are important for cellular function
-Metals are important for protein function
-Deficiencies in minerals can manifest in many ways
-Little is know about the role of minerals in disease
-Metalloproteins play pivotal roles in normal cellular
function and in disease pathologies.