The galactic double star system SS 433 consists of a high-mass, young giant star, which is presumably encircled by a black hole. The latter devours gas that flows out of the giant star. The energy released in the process spews a very small proportion of the overflowing gas into space in the form of two bundled rays known as jets. The spatial direction of the jets changes at regular intervals due to the effect of tidal forces. This causes the formation of a spiral structure like this computer simulation of one of the two jets.
The rotation of this biological rotor provides energy for the formation of the molecule ATP and thus the fuel required for the energy supply to all living cells. It was found in the cell membrane of the bacterium Ilyobacter tartaricus. The rotor’s ring diameter is around five nanometres. Scientists were able to generate a three-dimensional structural model of the rotor which is composed of eight identical protein sub-units. To do this, they crystallised the insulated ring of carbon subunits with lipids. The electron microscope images of the crystal were evaluated by computer and then converted into an electron density map.
Chlamydia tracomatis is one of the most common sexually transmitted pathogens – 90 million new infections arise throughout the world each year. The bacteria cause diseases of the urogenital tract. Chlamydia, which measure just 0.5 micrometres and are among the smallest bacteria that exist, can only reproduce inside cells. They survive in so-called inclusion bodies (green) and exploit the host cell's metabolism. The invaded cell eventually bursts and releases hundreds of new infectious particles. Researchers are aiming to track down the pathogen’s virulence mechanisms with the help of molecular-biological techniques.
The Neisseria bacteria shown here are just one thousandth of a millimetre in size. These pathogens, which are also known as gonococci, cause the sexually transmitted disease gonorrhoea. In the early stages of an infection, they accumulate in sets of two and four at the cells of human mucous membranes. This detailed image clearly shows how the bacteria succeed in being absorbed by the mucous membrane cells: the cell membrane has already closed around some of the gonococci. This marks the beginning of the infection, which can result in inflammation and copious pus discharge.
Scientists use photoelectron and photoion spectroscopy to study the electronic properties of solids and gaseous samples: energy-rich light can knock electrons out of matter. Scientist can then draw conclusions about the electronic structure of matter from the flight path and speed of the electrons. The sample in the image, which is being hit by the light beam from a free electron laser (FEL), is located in the brightly shining centre of the ball. Sensors on the walls of the ball, known as time-of-flight spectrometers, trap the electrons. The entire system is cooled using liquid nitrogen, which is trickled onto the middle of the array from above and escapes below it in a cloud.
Fusion power plants are supposed to harness energy from the fusion of atomic nuclei, in a similar way to the sun. The fusion fuel, an ultra-thin hydrogen plasma, has an ignition temperature of over 100 million degrees Celsius. Even the vessel walls reach temperatures of a few hundred degrees. Researchers therefore have to develop heat-resistant materials for the construction of such plants. The sample shows a wolfram alloy, into which silicon and chrome have been incorporated to make the material oxidation-resistant. Under the microscope, stress cracks can be seen. These are caused by the different rates of thermal expansion - an effect that should be avoided during subsequent application..
Powdery mildew (Golovinomyces orontii), a plant pest from the sac fungi group, forms a thread-like mass or mycelium on the leaves of the thale cress (Arabidopsis thaliana). The sporophores which protrude from the mycelium develop stacks of asexual spores at their tips which are spread by the wind. This way, the fungus can infest other plants. Scientists use the interaction between powdery mildew and the thale cress as a model system for studying how plants react to fungal infestations and how the fungi deal with the plant’s defence mechanisms.
Tiny cones of silica gel grow in an ordered arrangement on a glass surface. Inside, they consist of nanometre-sized silica gel tubes that wrap themselves in a spiral around an axis – like liquorice spirals. The central symmetrical axis already exists in the seed of the cone and is responsible for the subsequent appearance and characteristics of the silica forms. The tubes contain ordered organic molecules. Therefore, the entire arrangement has a hierarchical structure. Up to now, hierarchical structures were mainly known from nature, for example from bone development.
What looks like an exotic flower at first glance, is, in fact, the human immune system in action: a white blood corpuscle (shown here in red) is in the process of disarming tuberculosis bacteria (yellow). The pathogens are encircled by the scavenger cell membrane, pulled into the interior of the cell and locked in there – ideally forever. However, Mycobacterium tuberculosis is an extremely tough customer: thanks to a particularly resistant membrane, the bacteria can survive for many years inside the scavenger cells and may be released again if the host immune system is weakened, for example through diseases like AIDS or the effects of ageing.
Dark matter is not visible, it does not emit any kind of radiation, yet it exists – as its gravitation attracts other, standard matter. This computer simulation makes dark matter visible; it shows a virtual cosmic network of dark matter that connects individual, brightly shining galaxies in the universe with each other. The colourful image is part of the Millennium Simulation Project and demonstrates the enormous variety and complexity that arises from the gravitational dynamics of the dark matter particles. Differences in brightness represent the local density, and the colours represent the different speeds of the matter.
In order to thrive, plants require sufficient nitrogen. If nitrogen is lacking, they must cut back on photosynthesis and growth. To deal with this, plants have developed various strategies, for example the increased formation of the red leaf dye anthocyanin, which protects against excess light irradiation. Scientists suspect that the mechanisms that regulate anthocyanin also regulate the formation of the leaf hairs, which protect the plant against dehydration. Therefore, as part of studies on the effect of nitrogen deficiency, the size and number of leaf hairs were examined. The image shows just such a leaf hair from the thale cress plant (Arabidopsis thaliana).
The zebrafish (Danio rerio) is a popular model organism in developmental biology. It grows from a fertilised egg to a sexually mature animal within a period of three months. The image shows two-day-old larvae, in which the mouth opening can already be clearly identified. However, at first glance, the apertures which look like eyes surrounded by eyelashes are, in fact, the organisms’ future olfactory organs. The scientists at the Max Planck Institute for Developmental Biology study tissue and organ development in zebrafish embryos. A genetic defect in the embryo on the left causes problems in the development of the skin.
Max Planck Institute for Developmental Biology, Tübingen / Jürgen Berger, Mahendra Sonawane
A ramified vein winds its way through the spinal cord of a rat. The blood stream transports vital nutrients to the neurons and removes waste substances. Normally, the cell wall of the blood vessel forms a barrier that protects the sensitive neuronal tissue against pathogens. However, in diseases such as multiple sclerosis, cells from the body’s own immune system penetrate this protective barrier: aggressive T cells – shown here in red – adhere to the blood vessel wall and move along it. They eventually force their way through the wall and penetrate into the spinal cord, where their contact with scavenger cells or macrophages triggers the invasion of more T cells. Inflammation arises as a result and damages the neurons.
Although it was already in use in ancient China, cast iron is to this day a popular subject of current basic research. As an alloy with spheroidal graphite, it is as malleable as steel, but significantly less complicated and less expensive to produce. Also known as spheroidal iron, it is used for the production of pipes, in the automotive industry or in reactor technology, for example. The image shows the microstructure of the alloy: the spherical nodules of carbon appear as round islets; the fine network of lines indicates where different grains of materials collide. Max Planck researchers are studying the effect of this microstructure on material properties. They would like to be able to tailor the structure and thus the properties of the material to different applications.
The zebra fish (Danio rerio), a striped fish around five centimetres long, has similar heart genes to those of human beings. The signalling pathways that control the organ’s formation also match to a large extent. This small animal is thus a popular model organism. Scientists suppress the formation of specific signalling proteins and observe the effects on organ development. The image shows a normally developed heart of a 48-hour-old zebra fish embryo, dyed using fluorescent proteins. At this point, the heart measures only half a millimetre and – as in all fish – consists of an atrium and a ventricle. The heart muscle cells are highlighted in green, and the cell nuclei in red. The atrial myosin – a protein that only exists in the atrium – glows blue.
This flower of the thale cress (Arabidopsis thaliana) shows its stamens clearly visible - scientists at the Max Planck Institute for Plant Breeding Research lightened the tissue using a solvent. The pollen grains appear bright blue under the fluorescence microscope. The photograph was produced as part of a project on the effect of copper deficiency on plants. Copper is important for, among other things, the formation of lignin, which guarantees both the stability and functioning of the vascular bundles in plants and the release of the pollen when the flower opens. A lack of copper in agriculture, for example in cultivation on sandy soils, causes considerable reductions in yields.
Precious feathers were much prized in Pre-Columbian Central America; they played an important role as tribute, as cult offerings and as part of rulers' regalia. The feather mosaics of early colonial Mexico link this tradition with European figurative culture. Made of the finest feather fragments, they represent Christian motifs derived from European prints imported for missionary purposes. In turn, the feather icons were brought back to Europe as diplomatic gifts – shimmering testimonies of the early encounter between the arts of the Old and New Worlds. Here exotic humming bird feathers are used to represent heaven in a picture of the Evangelist John. The poor conservation is also evident: insect damage threatens the iridescent colours.
Detail of a feather mosaic, Saint John the Evangelist, 16th/17th century, Colección Daniel Liebsohn, Mexico City
Learning and memory are based on the constant modification, dismantling and re-establishment of the connections between cells in the brain. Simplified models are needed to enable scientists to study and understand these complex processes. Researchers at the Max Planck Institute for Brain Research grow neurons in fine microchannels on plates with a photolithographic structure. In this way, the complex three-dimensional network of neurons in the brain is reduced to two dimensions in the cell culture. The researchers can thus analyse how the synapses between the cells form or dissolve, and examine the role played by substances like neurotransmitters in these processes. This cell culture technology is also of great interest for the development of new active pharmaceutical substances.
Chaos often arises when non-linear processes unfold. The minutest changes can have major impacts, as in the case of the climate, for example. In this simulation, however, a non-linear interaction has a more ordering effect: a very intensive flash of ultraviolet light lasting just 100 femtoseconds – one femtosecond corresponds to the millionth of a billionth of a second – runs from left to right through the noble gas xenon. After a time a soliton – a type of super light pulse that is stabilised by non-linear processes – splits from the light pulse, which can be seen in yellow on the left-hand edge of the image. Unlike normal light or water waves, solitons do not dissolve. The merely 15-femtosecond soliton can be identified as the sharp line, the most intensive areas of which are red.
One day, magnetic vortex structures, like the one shown here, could help to process data particularly quickly. These structures arise in magnetic wafers of one micrometre in diameter and just a few nanometres thick. Unlike in a standard permanent magnet, the individual magnetic moments, which can be imagined as tiny rod magnets, order themselves in these wafers: their magnetic field forms needles which project from the front (red) or back (blue) of the disk and can thus store the zero or one of a data bit. Short magnetic pulses flip the needles from one direction to the other with lightening speed. The simulation shows the transition with the needles to the front (red) and back (blue). The magnetic moments in the orange and green areas only project slightly from the image plane.