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ISSUE 13 jANUARY 2011
Big
Picture
THE CELL
bringing CUTTING-EDGE SCIENCE INto THE CLASSROOM
Insider
knowledge
Revealing the secrets of your cells
e
E
FRE
© David S Goodsell, 2000
fo r t e a c h
a n d le a r n e
rs
A res o
ce
rs
ur
What are cells for?
How do cells divide, develop
and communicate?
What are stem cells and
why are they important?
What happens when cells die?
Big
Picture
Contents
Big Picture
6–7
8–9
10–11
12–13
Beginnings and basics
Big Picture is a free resource for teachers,
school and college students, and learners
of any age
...
Here’s how to get the most from
your issue
...
3
Introducing the cell
14–15
How do cells divide, develop and grow into complex organisms?
Cells and their surroundings
How do cells interact with their environment?
A matter of life and death
How long do cells live? What happens when they die?
Stem cells and development
What are stem cells and how are they used in medical research?
Stem cells and the future
What might developments in stem cell science mean for us?
Real voices
Three people’s stories about the roles of cells in their lives
...
The issues are divided into doublepage spreads, each dealing with a different aspect of the topic
...
Every issue contains a series of ‘real voices’ – interviews
with people whose lives are affected and shaped by the topic in
question
...
Using stem cells
You seem different…
How are cells specialised
Stem cells
What do we mean by
2
stem cells?
be
all its descendants will
If a differentiated cell divides,
do more,
other
...
They’re
producing stem cells and
on
means that they can go
also self-renewing, which
and on dividing
...
A newly fertilised totipotent cells
...
the placenta, and so can
egg in
a few steps beyond the
Embryonic stem cells,
– they can become any
development, are pluripotent
but not a whole organism
...
Most
and organs) are multipotent
...
between
focuses on the transitions
A lot of research
is whether pluripotent
these states
...
continuing signal to remind
cells
that embryonic stems
Research strongly suggests
cells, as
keep making more stem
are self-sustaining, and
protein
signals from a particular
long as they receive no
that triggers cell differentiation
...
Pluripotent
to test drugs
give researchers the chance
but only if they can
on different types of cell,
how and when
develop ways of controlling
these stem cells differentiate
...
Researchers single adult
are using
Cambridge, for example,
the biological signals
skin stem cells to explore
Scanning electron micrograph
Many types of cell are
in the lab for research
...
The cell keeps
so that
of which end is which,
way
...
These hair cells,
cilia, have
have a bundle of fine
have to
a top and bottom, but
direction
be arranged in the right
well
...
3
© 2010 Nucleus Medical
Art, all rights reserved
...
nucleusinc
...
Source:
Organs can grow by
getting more cells,
or larger ones
...
An organ can grow in
it
Adding more cells makes
bigger
...
We use
heart
methods
...
By exercising, we stimulate
hearts of
this process, and the
larger
athletes can grow much
still
...
be kept alive outside
Many kinds of cell can
dish
...
Many cell
reproduce, you have a
are used in research
...
(a layer one cell
usually consist of a monolayer the mix of cells
cell, not
thick) of a single type of
also lack the threefound in real tissues
...
cells in carefully ordered
is as much art
Successful tissue culture
carefully controlled
as science
...
The longest-lived
the medium they grow
cancer cells, which
cultures often derive from
normal controls
have found ways to override
lines have to be
on cell division
...
The
do in a tumour that’s
go on changing, as they
easy for cultures to
still in the body
...
If this
become contaminated
may not be
goes unnoticed, experiments
think
...
and function
...
An epithelial
sheet, for example, is
– the
asymmetric
...
surface
opposite face – the basal
of
– sits on supporting layers
tissue
...
This approach
involved in cell differentiation
drugs for, in this
can also be used to screen
tissues
...
biotechlearn
...
nz
Munich
– not
Stem cells are very special
s but
only can they renew themselve ted
differentia
they can also become an embryo
in
cells
...
potential for
control the
If we can learn how to
cells we might be able
differentiation of stem
of cell damage in the
to remedy many kinds
cells are pluripotent,
body
...
companies use
Some pharmaceutical
test new drugs
...
Small regions
c
Islets of
for the role it plays; specifi
pancreas known as the
from
different
characteristics range
Langerhans contain four
general
make
making key proteins to
cell types, which each
Red blood
most
properties like shape
...
The
small
cells, for example, are
there – beta cells
common cells
shape
biconcave discs
...
area,
gives a large surface
cells specialise?
How do
oxygen
a signal
helping the cells to ship
A stem cell will receive
tissues,
that
from the lungs to the
from its surroundings
dioxide
pattern
and a little of the carbon
triggers a change in the
on and
the other way
...
smallest
g of
squeeze through the
a detailed understandin
red blood
they
capillaries
...
control
in effect
they start work, which
full
reduces the cells to bags
EM Unit, UCL Medical
of haemoglobin, the protein
School, Royal Free Campus
carbon
that carries oxygen and
distorted,
dioxide
...
For
sicklein the inherited disease
blood
cell anaemia, some red
cells become sickle-shaped
owing to abnormal haemoglobin
molecules clumping together
...
sub-populations of cells
...
for their roles?
Also on this site, you can download PDFs of the current and all
13 past issues of Big Picture
...
Normal heart (cut section)
...
In heart failure,
things
can result from many
diet and
such as infection, poor
is an
high blood pressure, there
heart that
increased load on the
Medical Art Service,
Big
Picture
As well as twice-yearly magazines, there’s loads of other
useful material available on the Big Picture website
(www
...
ac
...
The exclusive online
content is created for each issue, and includes articles, videos,
games, image galleries, animations, lesson plans, activities and
more
...
too thick
Heart muscle becomes
(hypertrophy)
...
in
case, despite the increase
actually
size, heart performance
worsens
...
JANUARY 2011 • 11
THE CELL
1 Title – Each spread deals with a particular aspect of the
title topic
...
Article – Each article can be used alongside others from the
same spread or the rest of the issue, or as a standalone
component for a lesson
...
3
2 • Big Picture 13: THE CELL
Left-hand menu – Browse Big Picture online by title,
article, activity or resource
...
3
Recent issues heading – Explore the online content
for past issues
...
Introducing the cell
Join us as we explore the building block of life
...
Some
simple organisms consist of just one cell,
whereas more complex beasts, like us, have
vast numbers of them
...
Prokaryotic
organisms (such as bacteria) are simpler:
cells still with DNA, but having no nucleus
or membrane-bound structures
...
The intricately organised insides of
eukaryotic cells allow them to have different
things happening in different compartments
...
Having distinct spaces does half
the job, but it also requires sophisticated
machinery to ensure the right things get
into each section
...
Part of the cytoskeleton
are poised to break down the material into
smaller molecules
...
It recognised that
living things are made of cells, that cells
are the basic units of life, and that new
cells are created by old ones dividing into
two
...
We describe these as acellular, and they are
not considered to be living
...
So join us to explore
what we know – as well as what we still don’t
understand – about the cells that are the
basis of all of us
...
Responsible for
cell movement and changes
in shape, and make muscle
contraction possible
...
Rough ER is
studded with ribosomes and
is a site where proteins are
made, modified and processed
for shipping
...
It surrounds the cell and
enables it to communicate with its
neighbours and detect and respond
to changes in the environment
ribosomes – molecular machines,
built from RNA and protein, that
make new proteins
...
So, how
do cells divide, develop and work together to make this possible? And
if each of our cells contains all of our genes, then how do they turn into
different types of cell with distinct structures and functions? Why can’t
our cells go on dividing for ever?
Dividing we stand
The Golgi apparatus, which processes
and packages proteins in the cell
...
The most complex thing a cell can do is to split into two identical
cells
...
The duplicates
separate into different halves of the cell and then, during mitosis,
the cell splits down the middle – and then the cycle starts again
...
Each chromosome pair is
separated, so that each cell has a single chromosome
...
The movements of the chromosomes, like those of the cell, are
controlled by microtubules
...
Microtubules play a crucial role in mitosis, rearranging
themselves from their usual place in the cytoskeleton to build
a complicated machine called the mitotic spindle, whose other
parts include motor proteins
...
It pulls the pair of chromatids
that make up each chromosome in opposite directions so they
end up in different halves of the cell
...
A key
component is the protein complex (two or more proteins that
associate with each other) that assembles on chromosomes and
provides a place for microtubules to latch on to, known as the
kinetochore
...
Paul J Smith and Rachel Errington
Human cancer (melanoma) cells dividing
...
No one knew that cells existed
before the invention of the
microscope
...
The insides of
cells were observed much
later, with more powerful light
microscopes
...
2 µm (micrometres, millionths
of a metre)
...
Today, they can
even show how single molecules
of newly made protein nestle
inside the ‘chaperone’ proteins
that help them fold up into their
proper shape
...
Understanding
how proteins fold properly is
important, because misfolded
proteins can accumulate
and cause diseases such as
Alzheimer’s
...
The store of genes in the cell
nucleus, the genome, makes your
cells human
...
The differences lie in which genes
are actually in use
...
The genes, in turn, will
generate unique patterns of RNA
messages from reading the DNA
that is in use, and a signature
population of proteins and smaller
regulatory molecules
...
The result
is a complex developmental
conversation
...
But there is also a sense in which
the cell, with its surroundings, is in
charge of the information store in
the nucleus, and how it gets used
...
This is registered in the
transcriptome (the complete
catalogue of messenger RNA
molecules in a cell), and the
proteome (the list of all the
different proteins present)
...
How the
transcriptome and proteome
are tweaked by small changes
in the cell’s circumstances is
one of the biggest topics in current
biological research
...
It is important to have just the right amount
of cell division, so the process has lots of
checks and balances
...
Each time a chromosome
is copied, a repetitive stretch of DNA at its
end, the telomere, gets shorter
...
In effect, telomeres count cell
divisions
...
Stem cells, and
many cancer cells, can get round
this limit using the enzyme
telomerase, which
rebuilds the ends
of chromosomes
...
Soluble molecules move around apparently
randomly in the cytoplasm, but many components are transported more precisely
...
Cells also have an elaborate network of
fine protein filaments (strands), an interior cytoskeleton, which helps them keep their shape and
provides the rails of a transport system
...
Special labels ensure the right cargo is sent
to the right destination
...
The same system also moves organelles around or anchors them in place
...
A protein molecule might take
years to travel the length of the longest nerve cell by simple diffusion, but if it is bagged up and
dragged along a microtubule it can cover 10 cm in a day
...
Prof
...
Skeletal
muscles, such as your biceps, have
very long cells with many nuclei
...
Some cells in adult
heart muscle have two nuclei
...
Why does this happen?
We don’t know for sure, but one
recent idea is that one nucleus lies
dormant, but triggers further cell
division if the muscle gets damaged
...
For more on these cells,
see page 10
...
Under development
Controlled cell division is a
key part of development
...
In connective tissues, like bone
or tendon, this material – the extracellular
matrix – predominates
...
In all tissues, the
cells and their matrix communicate, chemically
and physically
...
One end of an
integrin is tied into the cytoskeleton, the other
to collagen fibres in the extracellular matrix
...
These
C Merrifield and M Duchen
Cells communicate with the matrix
surrounding them
...
include growth factors and signal molecules,
which affect many processes, including cell
migration
...
FAST FACT
Human eggs are made in
the embryo, so the egg
cell that fused with a
sperm to become you
was actually produced
around six months before
your mum was born
...
Controlled cell division
is crucial for development
...
Disruption of one of the
many genes involved in controlling
all these subtle shifts increases the
risk of developmental defects
...
Big
Picture
Cells within cells?
Cells and their
surroundings
In any multicellular organism, cells don’t
exist in isolation
...
How do cells
interact with their environment? What
happens when these signalling systems
are disrupted?
A society of cells
How do cells organise in an organism?
The human body is a closely organised community
of cells
...
These organs
work with each other in organ systems
...
The
remaining 20 per cent consists of several other
specialised liver cell types, along with blood vessels,
nerve cells and others
...
To keep the whole organism
functioning correctly, most organs or organ systems
also have to respond to the state of other organs,
which may be a long way away
...
They manage this in different
ways, but all use either chemical or electrical
signals
...
Heart muscle cells,
on the other hand, join to their
neighbours via gap junctions
...
This allows
waves of
depolarisation
to pass along a
series of heart
cells and keep
the heart beating
regularly
...
6 • Big Picture 13: THE CELL
Were some organelles
originally bacteria?
Some organelles inside eukaryotic cells look rather like cells
themselves
...
According to
endosymbiotic theory, eukaryotes originated when symbiotic
bacteria (which exist alongside cells in a mutually beneficial
relationship) began to live inside larger cells, giving them readymade compartments
...
Researching membrane proteins
Why do researchers study membrane proteins?
Around one-third of all proteins
are linked to membranes in some
way
...
But
examination of these proteins’
structure and function shows
how their roles in signalling can
be exploited, either by viruses
trying to bypass cell defences or
by researchers developing drugs
to treat disease
...
The virus enters
one kind of cell in the immune
system by first binding to a normal
cell surface receptor protein
called CD4
...
Several other
cell-surface receptors, and other
chemical messengers, can help
or hinder the fusion of membranes
...
R Dourmashkin
HIV particles budding from the surface
of a T cell
...
Cells have evolved efficient ways
of processing the many signals
they receive
...
When
the right molecule (the ‘first
messenger’) from outside the cell
binds to the receptor, it changes
shape, and triggers changes in the
internal protein as well
...
As cAMP is
produced after this small but
significant cascade of events, it is
known as a second messenger
...
Several important hormones use
cAMP as a second messenger
...
Different hormones whose
actions are mediated by cAMP
can cause the same response
in a given cell – for example,
adrenaline, glucagon and other
hormones trigger the breakdown
of triglycerides in fat cells
...
When messages between cells
are blocked or scrambled, there
are usually harmful results
...
In
multiple sclerosis, misdirected T
cells remove the insulating sheath
around nerve fibres, while tumours
begin when cells ignore messages
telling them not to replicate, or
when they misread signals to keep
dividing
...
Some diseases affect cell–cell
signalling directly
...
They build up from fragments
of a precursor protein present
at synaptic junctions, which is
abnormally processed
...
In
type 1 diabetes, sugar metabolism
gets out of control because the
cells that make the hormone
insulin die off
...
Colour-enhanced image of two myelinated nerve fibres
...
The cell’s plasma membrane
separates inside from out and
allows communication
...
Some just make pores that
allow small, soluble molecules to
get through
...
Other membrane proteins bind
signalling molecules, such as
hormones, that float by outside,
and then pass a message to
the interior
...
As usual, the
vesicles are tagged with special
proteins that label the contents,
and interact with yet more
membrane proteins to make sure
the correct cargo is delivered
...
Vesicles bud
out from one membrane, then
fuse with another
...
Karin Hing
Maurizio De Angelis
Ion channels in the cell’s plasma membrane
...
Cells can move slowly by crawling or
sliding along, aided by changes in the cytoskeleton, but faster
movements depend on specialised external organelles
...
The larger flagella
are used only to move cells
...
Research on how its movement is
activated, and how it changes when a sperm gets close to the
surface of an egg, may help overcome some causes of infertility
...
Cell movement is also an important part of wound healing
...
Two human bone-forming cells (osteoblasts) crawling over ceramic crystals
...
Joyce Harper, UCL
JANUARY 2011 • 7
Big
Picture
A matter of life and death
Cells have very different lifespans
...
For example, while men produce sperm
throughout their adult lives, women are born with all their eggs –
how might the age of a woman and her eggs affect any potential
offspring? Proper recycling and breakdown of a cell’s unwanted
parts is necessary to keep things in working order
...
Mark Lythgoe and Chloe Hutton
Cells can last a human lifetime, but not many do
...
Most,
though, last a good deal longer – liver cells for a year or so, bone cells
for perhaps ten years
...
Just a few kinds of cell can
endure from birth to their owner’s death
...
Building your brain
Can we grow new nerve cells
in our brains?
Some organs, such as the liver, can regenerate
if they are damaged, and will, within limits, grow
to cope with demand
...
Sadly, this will not
work for your brain: although ‘exercising’ your
brain may alter cell–cell connections, the
number of neurons will not change
...
If so, the numbers
New cells for old
The age of eggs and sperm can be very different
...
Human eggs (ova), on the
other hand, are made in the embryo, and released from the ovaries
much later on
...
After puberty, one oocyte a month matures
into a secondary oocyte, which can then be fertilised
...
Serious chromosomal problems may lead to miscarriage, so older
women are at greater risk of this than younger women
...
This might help to treat
infertility, or to reduce risks of some birth defects
...
Counting all the cells a person ever has would take several lifetimes
...
That ignores a lot of other cells,
like the 180 or so types of bacteria and other microorganisms that live in
and on our bodies
...
are small
...
It was discovered in the 1990s that the
hippocampus, where new memories form,
can produce new neurons late in life
...
If further work confirms this finding,
researchers will want to know whether the
cells can be activated, to help heal injuries
such as stroke or even, perhaps, improve
brain function
...
ker
Source: Scientific American, 5 January 2001
...
Cells, like people, die if they are starved or poisoned
...
A similar
obstruction in the brain leads to the destruction of brain
cells in a stroke
...
But a
cell’s life can also end in other ways
...
Cells have an inbuilt
self-destruct routine that keeps them poised on the brink
of suicide
...
This is a neat and tidy death
...
Apoptosis happens in different places at different times
...
Cells with damaged DNA
may sense the damage and sacrifice
themselves for the common good,
for example, when you get
sunburn
...
Triggering apoptosis
is one way that HIV depletes
the immune system of vital
defensive cells
...
Getting on a bit
Ageing cells have a
number of tell-tale signs
...
Old, tangled
proteins and other cellular junk
defy the lysosomal enzymes
...
Other signs of cell ageing, such as
shortening of the telomeres
on the ends of the chromosomes,
are related to how many times the
cell has divided
...
Mitochondria age faster
than other organelles
...
Mitochondria have some essential
genes in their own DNA, and
the proportion of them that have
serious defects increases as the
person, and their cells, grow older
...
The right packaging is
also crucial for recycling and
disposal
...
Larger vesicles
import material from outside
...
New vesicles bud off from here,
and shift designated contents
onward – to other parts of the
cell, back to the outer membrane
or to the lysosomes
...
al Ge
netics
Centr
e
FAST FACT
The 2009 Nobel Prize in Physiology or
Medicine went to Elizabeth Blackburn,
Carol Greider and Jack Szostak for their
work on how chromosomes are protected
by telomeres and the enzyme telomerase
...
nobelprize
...
The
main site for this is the lysosome,
which acts as a cellular stomach
...
Old organelles, other
cellular waste and, in immune
system cells, old red blood cells or
bacteria swallowed by the cell are
all wrapped in membranes of their
own
...
In cases where one of the
lysosomal enzymes fails, the cell
cannot keep up with removing
waste
...
The
JANUARY 2011 • 9
Stem cells and
development
Stem cells are very special – not
only can they renew themselves but
they can also become differentiated
cells
...
Stem cells
What do we mean by stem cells?
If a differentiated cell divides, all its descendants will be
identical to it and each other
...
They’re
also self-renewing, which means that they can go on
and on dividing
...
A newly fertilised egg and the products of
its first few divisions are made of totipotent cells
...
Embryonic stem cells, a few steps beyond the egg in
development, are pluripotent – they can become any
type of specialised cell, but not a whole organism
...
Most adult stem cells (those found
in differentiated tissues and organs) are multipotent
...
A lot of research focuses on the transitions between
these states
...
Research strongly suggests that embryonic stems cells
are self-sustaining, and keep making more stem cells, as
long as they receive no signals from a particular protein
that triggers cell differentiation
...
Red blood
cells, for example, are small
biconcave discs
...
The shape also gives
flexibility, helping the cells
squeeze through the smallest
capillaries
...
If the shape is distorted,
disease can result
...
Organs often contain
sub-populations of cells
...
Small regions of the
pancreas known as the Islets of
Langerhans contain four different
cell types, which each make
different hormones
...
How do cells specialise?
A stem cell will receive a signal
from its surroundings that
triggers a change in the pattern
of genes that are turned on and
off, directing the cell towards a
more specialised state
...
EM Unit, UCL Medical
School, Royal Free Campus
Sickled and normal red blood cells
...
This way up
Direction is important in cells’ development and function
...
An epithelial
sheet, for example, is
asymmetric
...
The
opposite face – the basal surface
– sits on supporting layers of
collagen and connective tissue
...
The cell keeps track
of which end is which, so that
molecules go the right way
...
These hair cells, which
have a bundle of fine cilia, have
a top and bottom, but have to
be arranged in the right direction
along another axis as well
...
Using stem cells
Stem cells hold great potential for
treating disease
...
Embryonic stem cells are pluripotent,
and so the most versatile, but their use
is not without controversy (for more, see
pages 12–13)
...
Stem cells
for studying specific diseases – including
Huntington’s, Parkinson’s, muscular dystrophy
and type 1 diabetes – have been made by
reprogramming adult cells from patients into a
pluripotent state
...
Adult stem cells (those found in
differentiated tissues and organs) are
potentially useful too
...
involved in cell differentiation
...
Getting some culture
Many types of cell are grown
in the lab for research
...
If they grow and
reproduce, you have a cell culture
...
To some extent, they can substitute for whole
organisms, particularly for animal testing of
toxicity or drug effects
...
They also lack the threedimensional structure of tissues and organs,
which have defined shapes and support their
cells in carefully ordered arrangements
...
Cells need carefully controlled
conditions to grow, including the right
temperature, gas mix and growth factors in
the medium they grow in
...
Such cell lines have to be
checked continually
...
It is also easy for cultures to
become contaminated by other cells
...
FAST FACT
Stem cell therapies are
already in use in the
form of bone marrow
transplants – the first of
which was performed
in 1956
...
An organ can grow in two ways
...
But so can increasing
the size of individual cells (called
‘hypertrophy’)
...
The embryonic heart
increases in size by adding extra
cells, but after birth, our hearts
grow by hypertrophy
...
This so-called physiological
hypertrophy is normal; when
you stop training, your heart
will adapt and slowly reduce
www
...
org
...
Heart muscle becomes
too thick (hypertrophy)
...
In heart failure, which
can result from many things
such as infection, poor diet and
high blood pressure, there is an
increased load on the heart that
stimulates hypertrophy
...
Medical Art Service, Munich
More, and bigger
Medical illustration copyright © 2010 Nucleus Medical Art, all rights reserved
...
nucleusinc
...
JANUARY 2011 • 11
Big
Picture
Stem cells and
the future
Advances in stem cell technologies are
occurring rapidly, bringing with them different
ethical, moral and social questions to consider
...
Umbilical stem cells
Many of the embryonic stem cells used in research in the UK
come from fertilised eggs donated by people undergoing in vitro
fertilisation (IVF)
...
The use of embryonic stem cells is controversial and opponents
argue that destroying embryos to remove stem cells is inhumane
...
Cord blood stem cell transplants have been used to help people
with diseases such as leukaemia and lymphoma
...
This is less likely to
happen than during bone marrow transplants, though, and as cord
blood banks grow, there will be a greater chance of finding suitable
matches
...
At first it was thought that cord blood stem cells were
only able to differentiate into types of blood cell, but research now
suggests that they may have greater potency than this
...
The stem cells were shown
to take on the properties of cells in the cornea of the eye, showing
the potential of this research to help those with loss of vision
...
”
“I don’t feel comfortable donating
my umbilical cord blood – who
knows what they might be able to
do with it in the future?”
Question: Should it become obligatory for women
who give birth to donate their umbilical
cord blood for research?
?
Snapshots of the stem cell story
•
•
1981: Scientists
successfully culture
(grow) pluripotent
mouse embryonic
stem cells
12 • Big Picture 13: THE CELL
1996: ‘Dolly the sheep’ is
the first mammal to be
cloned by somatic nuclear
transfer – adding a nucleus
from an adult sheep cell to
an unfertilised egg with
the nucleus removed
•
1998: Scientists at the
University of Wisconsin
isolate and grow the
first stem cells from
human embryos left
over from IVF
•
1990: Human Fertilisation and
Embryology Act passed in the
UK, includes founding of Human
Fertilisation and Embryology
Authority, which regulates the
creation, use and storage of
human embryos in treatment
and research
•
2004: Britain opens
the world’s first
government-financed
stem cell bank,
containing embryonic
and stem cell lines
K Hardy
Ph Plailly/Eurelios/
SPL
1958: Leroy
Stevens identifies
pluripotency
of certain
mouse cells
Wellcome Trust
Sanger Institute
•
•
2001: UK Parliament rules
embryonic stem cell research
can occur using government
funding
...
The egg is not fertilised, but is triggered to
develop with a jolt of electricity
...
However, the absence of
the regulatory chemicals present in a human egg makes such work tricky
to accomplish
...
Human admixed embryos are not allowed
to develop beyond 14 days, it is prohibited to implant them into humans or
animals, and their use is regulated by the HFEA
...
See below for the type of advert that this could lead to
...
Simply attend your local clinic and have
a small skin sample taken
...
No rejection! No immune-suppressing drugs!
But don’t take our word for it!
Marion, 41, says: “A lifetime of type 1 diabetes, and my disease was
gone after one procedure
...
Working
with stem cells created this way
will help me to research genetic
neurodegenerative disorders such
as Alzheimer’s and Parkinson’s
...
How do we know the
long-term effects of this?”
Question: What about using stem cells to
enhance humans – do you think
it would be acceptable to use the
same technology to make you
stronger or able to run faster?
Question: Is creating a human admixed embryo from a
mature human cell and an animal egg cell
for research more acceptable ethically than
using a human embryonic stem cell?
?
?
2008: The second UK Human Fertilisation
and Embryology Act passed, amending
the 1990 Act, allowing researchers, under
tight controls, to create animal–human
hybrid mbryos by replacing the nucleus
e
from an animal egg with a nucleus from a
human body cell
•
2007: A Japanese team
including Yamanaka and
Takahashi and a separate
US team create the first
induced pluripotent stem
cells from human cells
•
2009: An international team of
researchers creates the first
human induced pluripotent stem
cells without using viruses
•
2008: Scientists at the Harvard
Stem Cell Institute create stem cells
for ten genetic disorders, which will
allow researchers to understand
better how diseases develop in
cultured cells
Maurizio De Angelis
•
Domiwo/stock
...
wellcome
...
uk/
bigpicture/cell
for a lesson plan
to use with these
articles
...
Meet Spike
Walker, an award-winning micrographer, Olly Rofix, who was diagnosed
with a rare form of leukaemia in his early 20s, and Andrew Evered,
whose job as a cytologist means he screens cell samples for cancer
...
So I asked my father
for one
...
50
a week but he bought me one for
£4
...
And it’s been an interest for
65 years now
...
And it’s accessible
...
I can go up the lane, and take a
tubeful of dirty water out of one of
the ditches and I’ve no idea what
I’m going to see, out of possibly
30 000 species
...
The average cell in
your body does one thing
...
These
cells living on their own in water,
and do everything: they propel
themselves about, catch their
prey, digest it and excrete the
remains, and find a mate
...
It’s a very elastic,
transparent sack with a stout
whip sticking out the front end
of it, which propels it around
...
Sometimes I’m looking at
something else in a drop of water,
and suddenly one of these twitchy
little fingers appears in the corner
of your eye, followed by yards of
14 • Big Picture 13: THE CELL
nothing and then, unbelievably,
this sack-like body
...
What’s tricky about making
images with a microscope?
If you’re making a portrait of
someone, you can decide
exactly where your subject is
going to sit
...
But if you’re
photographing things in dirty
water, other things will be there
and they’ll swim in and out
...
What’s your favourite image?
There’s one of oxidised vitamin
C that got a Wellcome Special
Award of Excellence in 2008
...
The
crystals grew in the boxes, and
the image looks like a Victorian
wall decoration – little boxes with
shells inside
...
This year I won the Royal
Photographic Society’s Combined
Royal Colleges Medal – probably
for being the oldest micrographer
still in existence!
For a video on Spike and his
work, see www
...
com/
watch?v=Xo7mr90GYLA
What do you do?
I’m 25, I used to be an engineer
at the port of Felixstowe, but I left
work last year to concentrate on
rebuilding my boat
...
What are your plans next?
Next year I’m sailing around Britain
to raise money for the Anthony
Nolan charity
...
They
found me my donor and saved
my life
...
How did you find out you had
leukaemia?
I was first diagnosed in 2005 with
glandular fever because I started
to get very tired
...
The doctors told me
I was only the third person in the
world to be diagnosed with this
type of leukaemia – and the other
two were dead
...
Anthony Nolan scanned the
register and found me one with
a really good tissue match
...
Then they
gave me the new bone marrow
...
It took about two hours
for the bone marrow to drip in
...
Did the doctors tell you what
your prognosis was?
Yes, the survival rates of the
transplant then weren’t fantastic,
10 to 15 per cent
...
Now, I’m in remission, and if
I get the all-clear next March, that
will be five years post-transplant
...
I met him
and was able to thank him, as I
wouldn’t be here without him
...
oliverstravels
...
uk
...
anthonynolan
...
makeanotherme/iStockphoto
Extra online
resources
What cells do you look at?
Some 90 per cent of the screens
we do are cervical, for the UK’s
Cervical Screening Programme
...
The other 10 per cent are nongynaecological screens of cells
in body fluids: sputum, urine and
chest drains and so on
...
How can you spot a precancerous cell?
Through changes to the nucleus
...
It also increases its
uptake of the stains and dyes we
use to see it, so it looks darker
...
Do you find other things?
We find a lot of infections that
weren’t clinically suspected
...
And two common viral infections
we find are the human papilloma
virus (HPV) and the herpes virus
...
HPV
•
•
•
•
•
an animation and lesson plan on hearing
a guide to the evolution of cells
the story of Henrietta Lacks and HeLa cells
a video on working with cells in the lab
image galleries on cell division, cell types
and the history of cell imaging
...
Free to
use and share, the videos cover many different areas of biomedical
science, from appetite to MRI, Parkinson’s disease to chronic pain
...
www
...
com/wellcometrust
Cytologist
(screens cells
for cancer)
If you go into my cytology lab
you’ll see lots of people looking
down microscopes
...
They’re looking
at human cells on glass slides that
have been stained with dyes so
we can see them better
...
wellcome
...
uk/bigpicture/cell to find
more articles, videos, image galleries and lesson plans
around the cell
...
takes over a cell’s machinery, and
uses it to make its own new DNA
...
How do you become a cytologist?
I did a degree in biomedical science
and gradually moved up through
the ranks to become a consultant
...
You
have to develop the visual skills to
recognise cancer, and that takes a
lot of practice
...
You have to
work in a cytology lab and screen a
minimum of 5000 cervical smears,
then pass a rigorous exam
...
It takes several
more years of practice to become
proficient at reporting non-cervical
specimens
...
You do
the same two years’ training, screen
5000 samples and take the exam
...
What qualities do you need?
Your eyesight must be good or
possible to correct with spectacles,
and you must have passed a recent
standard eye test
...
It’s meticulous
work
...
Has the technology changed?
Unlike other areas of biomedicine,
such as haematology and
biochemistry, cytology hasn’t been
automated
...
The Wellcome Film YouTube channel is home to hours of archived
medical film, free to use
...
www
...
com/wellcomefilm
Free science images
Wellcome Images is one of the world’s richest image collections,
with themes ranging from medical and social history to contemporary
healthcare
...
Images are free to
browse and use for educational purposes
...
wellcome
...
uk
About the cover
The cover image is ‘Blood’ (© David S Goodsell,
2000) by David Goodsell, an Associate Professor
at the Scripps Research Institute, USA
...
There are Y-shaped
antibodies, long, thin fibrinogen molecules (in
light red) and many small albumin proteins in the
serum
...
The cell wall, in purple, is
braced on the inner surface by long spectrin chains connected at one
end to a small segment of actin filament
...
scripps
...
Wellcome Trust: We are a global charitable foundation dedicated to achieving
extraordinary improvements in human and animal health
...
Our breadth of support
includes public engagement, education and the application of research to improve
health
...
The future of science depends on the quality of science education today
...
wellcome
...
uk)
...
0 UK
...
This is an open access publication and, with the exception of images and illustrations, the
content may unless otherwise stated be reproduced free of charge in any format or medium,
subject to the following conditions: content must be reproduced accurately; content must
not be used in a misleading context; the Wellcome Trust must be attributed as the original
author and the title of the document specified in the attribution
...
210183
...
2711000
(whose registered office is at 215 Euston Road, London NW1 2BE, UK)
...
But
how can cells grow and develop to form
such complex creatures? In this issue of Big
Picture, we explore the secrets of the cell –
looking at both what scientists understand
so far, as well as what’s still to be uncovered
in this area
...
Explore
how cells communicate with each other
and their surroundings to keep everything
in working order, and what happens when
these processes goes wrong
...
Finally, we ask if stem
cells might really hold the secret to treating
and curing many diseases, and – if so – at
what cost?
Big Picture subscriptions
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16 • Big Picture 13: THE CELL
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ooM
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d?
ou
What is
addictio
How is
n?
the bra
in addic
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tion?
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ad
What mi diction treate
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FREE
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