Wellcome Image Awards 2012

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What

are the spiky structures on the leaf surface?

The surface of the leaf is densely covered with fine hair-like outgrowths made from specialised epidermal cells called non-glandular trichomes, which are found on a wide variety of plant species. The hairs keep frost away from the surface cells and break up the flow of air across the leaf surface, reducing evaporation. Dense coatings of trichomes also reflect solar radiation, protecting the delicate tissue beneath. In habitats where plants rely on their supply of water from cloud drip, trichomes have been found to enhance this collection process. In addition, trichomes protect the plant against pests because the hairs interfere with their feeding process. Glandular trichomes, which contain volatile oils and other secretions that are produced by the plants, are also present on the surface of the leaf.

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Why

did the judges like this image?

Alice Roberts (anatomist, author and TV presenter) explains: "This gorgeous, extreme close-up of the surface of a lavender leaf, viewed through a scanning electron microscope, clearly shows the bulging droplets of oil that provide the plant with its heady scent. Artificial colour has been used brilliantly here, to pick out the salient details, but also gives the image a startling Avatar-like quality."

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Why

was this image created?

Vincent and his colleagues are researching ways to perform cell replacement therapies in humans to replace damaged tissue. Replacement cells need to be derived from the patient to avoid problems of rejection and the need for immunosuppression. For example, skin cells from patients can be reprogrammed into an embryonic state, allowing them to form any cell of the human body. However, only a few cells can be induced to go back in development, and the efficiency of deriving new heart, pancreas or liver cells from these cells is very limited.

Xenopus oocytes are being used to understand nuclear reprogramming to increase its efficiency, with the long-term aim of providing patient-specific replacement cells. By transplanting the nuclei of adult cells into frog oocytes, scientists can identify the mechanisms by which somatic cells (cells of the body) can be reprogrammed. To allow scientists to inject inside the oocytes for experiments, the follicle cells need to be removed. To ensure that the removal procedure has worked, follicle cells can be easily visualised, as depicted in this picture of an untreated oocyte.

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Why

is Xenopus laevis used as a model organism?

Xenopus is one of the main model organisms used in cell and developmental biology. Xenopus research has helped to uncover key fundamental mechanisms of embryonic development, including morphogenesis, cell differentiation, organogenesis, cell cycle regulation, regeneration and nuclear reprogramming. The main advantage of using Xenopus is that it provides numerous and large oocytes and eggs. Importantly for Vincent's research, Xenopus have the remarkable ability to reprogram the nucleus of an adult cell, for example skin or muscle, to form an oocyte or embryonic-type cell. These cells possess the ability to form all other cell types in the body.

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What

is the timeframe of the mitotic steps?

HeLa cells undergo cell division approximately once every 16 hours. The cell spends a substantial portion of this time preparing itself for division during interphase, and the actual process by which the cell physically divides into two takes approximately an hour. The cell in the centre of the image has completed its journey through the first half of mitosis (prophase and pro-metaphase) by becoming round, then aligning its duplicated DNA in the centre (metaphase). It is now ready to pull the identical copies of DNA to opposing ends of the cell (anaphase, approximately eight minutes). This is followed by cytokinesis (approximately 15-20 minutes), when the contraction of the membrane and physical separation into two daughter cells occurs.

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Why

is the image arranged in this spiral shape?

Kuan-Chung Su explains: "Over 200 years ago, it was proposed that cells arose from pre-existing cells. We now know that cell division is a fundamental characteristic of life on Earth. All living organisms begin with a single cell that divides repeatedly with astonishing precision to create organisms so complex and wonderful. The spiral arrangement best captures the journey of a cell as it proceeds to divide and create new cells in the process. One could imagine the spiral to spawn an infinite number of interlocked spirals, each representing a single cell but as a whole capturing the beauty of life."

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Why

is Arabidopsis used as a model organism?

Arabidopsis thaliana is used across different laboratories for plant research. The plant has several advantageous features that make it suitable for genetic and molecular biology research. A large proportion of its 125-megabase genome has been sequenced, and genetic maps of all five chromosomes are available. In addition, its short life cycle (approximately six weeks from germination to seed maturation) allows rapid experimentation. Importantly for laboratory conditions, Arabidopsis is easily cultivated in limited space. This has led to a large collection of mutant lines, standard protocols for growth and transformations and well-described cellular organisation of tissues.

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Why

did the judges choose this image?

Alice Roberts (anatomist, author and TV presenter) explains: "I love this slightly ethereal image. It has an other-worldly, magical quality to it. But what we're looking at are the cells of the diminutive brassica, Arabidopsis, much loved by plant geneticists."

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What

are the physiological effects of caffeine consumption?

Beverages containing caffeine - including coffee, tea, soft drinks and energy drinks - are extremely popular, and 90 per cent of adults consume caffeine daily. Caffeine acts as a metabolic stimulant on the central nervous system, reducing physical fatigue and drowsiness. Less than an hour after consumption, caffeine is reported to improve the flow of thought and increase focus and body coordination. However, the amount of caffeine required to produce these effects depends on a person's body size and degree of tolerance. The effects usually disappear after five hours. Too much caffeine can cause restlessness, nervousness, insomnia, nausea and vomiting, but normal levels of consumption (approximately 200-300 mg daily) pose few known health risks.

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Why

did the judges like this image?

James Cutmore, Picture Editor at BBC Focus Magazine, explains: "What interests me in my professional role is showing our readers images of everyday things from a different, at first unrecognisable, perspective. For that reason, this image really grabbed my attention. It's a bright, intricate image of something that most of us experience every day."

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What

does this image show?

The image shows the central chicken embryo surrounded by the vitelline vascular system, the veins and arteries supporting the flow of blood between the embryo and the yolk sac. The head of the embryo, including the embryonic eye and brain, can be seen on the upper part of the embryo, just above the embryonic heart. The long lower part of the embryo is the future body of the chicken, from which legs and wings will develop.

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How

was this image acquired?

The image was obtained by opening the egg's shell and injecting a fluorescent dye into the vascular system (the lower part). Because of the action of the pumping heart, the dye spread to the entire vascular system (vitelline veins and arteries). Images were then recorded using a fluorescence microscope equipped with a camera. The image shows the whole embryo as a result of monitoring total reflected fluorescence.

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What

does the image show?

The cells in this image are human breast cancer cells with nuclei labelled blue and mitochondria labelled red. The cells are squeezed into micro-scale channels to study large numbers of single cells migrating with varying concentrations of epidermal growth factor (EGF, shown in green) at the leading and trailing edge of the cell. This technique is being used to study cell structure during chemotaxis to help explain this complex process in the context of tumour cell dissemination.

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Why

was this cell type used?

Salil Desai explains: "These are MDA-MB-231 breast cancer cells and a known migratory cell type. They are a good choice for our experiments as they have well-characterized chemokine response and migration velocity. They are also widely accepted in the cancer literature as a model migratory invasive cell line." This research is also applicable to other types of cancer cell, including prostate, ovarian and lung cancer cell lines. Experiments with these cells are ongoing in Salil's laboratory. He explains, "These devices can also be tailored using digital design tools to create narrower or wider channels to incorporate different types of cells and to create different types of confinements for the cells to navigate."

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What

was involved in this surgical procedure?

This photograph was an integral part of the operative process. First, this initial image was taken of the brain in its natural state. The surgeon then attached a flexible electrode grid, with a unique series of numbers at regular intervals along it, to the surface of the brain. Once the grid was applied, a second photograph was taken to record its position. The patient then underwent a CT scan to confirm the correct location of the grid implant on the brain and was taken to the telemetry ward, where they were observed and the electrical activity of their brain was recorded for up to two weeks. Post-observation, the surgeon reviewed the recordings and evaluated the data using the unique numbers on the grid implant, which was then used to identify the specific areas of the brain to be removed during the next operation. This patient made a full recovery and no longer suffers from epileptic fits.

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Why

was this chosen as the overall winner?

Alice Roberts (anatomist, author and TV presenter) explains: "This is a stunning image. Taken during an operation, which allows surgeons access to inside the skull, for recording electrical impulses, we are looking at the surface of a living brain. It's just extraordinary: the 'grey' matter (which is grey in death) is blushing pink. Small arteries are glowing with the scarlet blood pulsing through them, while purple veins lie thickly in the sulci, the crevices of the brain. And underneath that is somebody's mind. For me, the context, the composition and the clarity of this image made it a winner."

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Why

was the creator looking at this fly?

Kevin Mackenzie explains: "This small fly was resting on the interior kitchen wall at home. Even to the naked eye, it was unusual in appearance – like a tiny moth, holding large wings across the top of a distinctly fuzzy body. I'd seen nothing like it before, so it definitely warranted a closer look under the scanning electron microscope."

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How

was the sample prepared for imaging?

The fly was placed directly into a tube containing ice-cold 100 per cent methanol that had been cooled to -20°C, and it was then placed back in the freezer for 24 hours. After this time, it was removed and allowed to thaw out at room temperature. The specimen was then placed into 100 per cent ethanol and transferred to hexamethyldisilazane and air dried. This method minimised possible damage to the fine hairs and scale of the fly. The dried sample was attached to an SEM mounting stub and lightly coated with a thin layer of gold before being imaged using the backscatter detector. See the section on SEM techniques for more information.

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How

is the frustule formed?

A frustule is composed of two halves, known as thecae. As the diatom divides, each daughter cell retains one theca of the original frustule and produces one new theca. As the diatom prepares to separate, the newly formed nucleus and the pre-existing nucleus each move to the side of the diatom where the new hypotheca (lower half) will be formed. A vesicle known as the silica deposition vesicle forms near the plasma membrane. This forms the centre of the pattern, and silica deposition can continue outward from that point until the frustule is produced.

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Why

does it look like a radiation symbol?

Anne Weston explains: "In fact, the question here should be 'Why does a radiation symbol look like a diatom?' because the diatom would have existed long before the radiation symbol was designed or even thought of! There are thousands of species of diatoms, and this particular type just happens to have this unique and interesting structure."

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What

causes this heart defect?

A VSD is usually seen as a congenital condition, where the defect is present at birth or manifests itself in the first month after birth. A traumatic VSD, as in this case, is a rare complication of chest injury. It might manifest immediately after trauma, leading to heart failure and an inability to stabilise a patient, or the presentation might be delayed and detected months later. As a result of the hole in the ventricle wall, blood leaks from the left ventricle into the right after ventricular contraction. The blood passes through the lungs before re-entering the left ventricle via the left atrium. The leakage results in pulmonary hypertension, or high blood pressure, which causes breathlessness, dizziness and fainting.

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What

part of the procedure is shown in the image?

Traumatic VSDs can be treated in a variety of ways, depending on the effects they have on the patient. Treatment options range from a conservative approach and monitoring to open surgery, as is depicted here. In this image, the VSD is seen at the bottom, and a bovine patch is being stitched and parachuted into place to seal the defect.

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What

is synthetic biology?

The synthetic biology project that produced this image involved designing artificial genetic circuits for pattern formation in bacterial colonies and plant tissues. Synthetic biology is an emerging field that uses the principles of engineering for the construction of genetic systems. The approach is based on the use of well-characterised and reusable components and numerical models for the design of biological circuits. Synthetic biology provides a conceptual and practical framework for the systematic engineering of gene expression and behaviour in microbes, facilitating the design of novel regulatory networks including synthetic switches, intercellular signalling systems and metabolic pathways. Synthetic biology approaches also show great potential for the engineering of multicellular systems, such as plants, which are widely used in crop systems for the production of biomass, food, polymers, drugs and fuels.

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Why

did the judges choose this image?

Alice Roberts (anatomist, author and TV presenter) explains: "At first glance, this looks like a richly patterned fabric - but look closely, and you can see the tiny grains, each one an individual bacterium. It's a stunning image of a growing bacterial colony. It shows that the researchers are very much artists as well as scientists; they have a fine appreciation of the aesthetic in their work."

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What

is the drug's mechanism of action?

Loperamide is an opioid receptor agonist and acts on the mu-opioid receptors in the myenteric plexus, a network of nerve fibres in the muscular coat of the large intestine. Loperamide decreases the activity of the myenteric plexus, which acts like morphine to decrease the tone (muscle tension) of longitudinal smooth muscle but increase the tone of the circular smooth muscle of the intestinal wall. This increases the length of time that food stays in the intestine, allowing more water to be absorbed from the faecal matter into the body. Loperamide also decreases colonic mass movements and suppresses the gastrocolic reflex.

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How

were the crystals formed?

These crystals were re-crystallised from a pure laboratory sample. Annie used varying percentages of solvents to create the crystals and left them for two weeks before they were imaged. Slightly raised from the surface, this group formed in a very three-dimensional manner.

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What

are the advantages of this method of vaccine delivery?

Traditional drug and vaccine delivery typically involves the use of hypodermic needles, which cause pain and patient discomfort. In addition, because traditional needle delivery accesses the blood supply, needle reuse or needle-stick injuries to patients or healthcare providers can contribute to the spread of blood-borne pathogens. Microneedle application prevents this by avoiding contact with blood vessels and nerve endings in the deeper skin layers. In addition, because the skin is so accessible, microneedle application can be performed quickly, requires minimal training and makes self-application by patients possible. Microneedle delivery is a 'platform' technology, which is potentially useful for the delivery of a wide range of drugs in a variety of applications.

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How

were the needles made?

Microneedle fabrication begins with the generation of a rubber mould, made using a laser to engrave arrays of microneedle-shaped cavities into the surface of a rubber sheet. Biodegradable plastic is then melted, poured into the mould and allowed to cool. Microneedles can easily be fabricated from various different plastics and in many different shapes and sizes depending on the design of the rubber mould. The microneedles in this image are composed of the biodegradable plastic poly(lactide-co-glycolide), or PLGA. PLGA naturally degrades over time inside the body and has been used extensively in biomedical implants and devices such as re-absorbable sutures. In the case of microneedle design, PLGA is an ideal material because it is strong enough to penetrate the outer layers of the skin, but it is able to harmlessly degrade if it is left behind in the body.

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What

are the different parts of the alga?

The two semicells are joined by a narrow central bridge, or isthmus, containing the nucleus where the organism's genetic material is held. Each semicell contains a single chloroplast ? the site of photosynthesis. Chloroplasts within Micrasterias contain chlorophylls A and B and the enzymes required for photosynthesis. The sugar created is used to provide energy for the organism or, if it is not used, taken up by many small round pyrenoids, which are embedded in the chloroplast; they convert the sugar to a starch for storage.

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How

do these desmids reproduce?

Micrasterias can reproduce asexually by binary fission (resulting in two separate cells, each of which has one of the parent's semicells and one new semicell). During this process, genetic material is duplicated and two new semicells grow between the original semicells. Micrasterias can also reproduce sexually through a process known as conjugation, which involves the transfer of genetic material between two cells.

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Why

did the creator choose to colour the image in this way?

Anne Weston explains: "If I am colouring something like blood where there is an obvious colour that we associate with it, I will usually stick to that colour ? but for something like connective tissue, its natural colour is a bit non-descript, so I simply choose colours that I think work well together and are pleasing to the eye. Often I will colour a single image in a number of different ways, some more natural looking and some more vibrant and vivid. This one just happens to be a more natural-looking selection of colours that I thought worked well. There is no scientific significance behind the choice of these colours, they were self-indulgently chosen purely because I wanted to!"

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What

is arthroscopic surgery?

Arthroscopic surgery is a minimally invasive surgical procedure, in which the examination and treatment of the joint are performed using a specific type of endoscope known as an arthroscope. The advantage of this type of surgery is that only two small incisions need to be made: one for the arthroscope and one for the surgical instruments. The result is a reduced recovery time and reduced trauma to the connective tissue. This technique is used in many orthopaedic procedures, such as the removal or trimming of torn cartilage and ligament reconstruction.