LIFESCIENCES 2021

Nasturtium petal with a typical warty surface. Each of the warts is a cell that gives the petals their velvety appearance. The garden nasturtium (Indian cress, or monks cress, lat.: Tropaeolum majus) is an decorative and medical plant. It originates from western South America, the Incas already used the plant as a pain and wound healing agent. Because of its antibacterial effect, nasturtium is used in combination with horseradish for respiratory and urinary tract infections. Leaves, buds, flowers and seeds are edible and remind of watercress with their slightly peppery taste. Buds and unripe seeds can be used as a spice, leaves and flowers are usually served as a salad.

The picture shows the surface of a basil leaf on which trichomes (plant hair, gray) and oil containing trichomes (pale yellow and pale green) can be seen. The plant hairs have different functions, e.g. there are protective, stabilizing and glandular hairs. Here the gray-blue colored trichomes are for mechanical protection, the round and bun-shaped ones are filled with etheric oils and are called glandular trichomes, they burst when touched, protect the plant chemically and often contain medicinally effective substances and aromas. Basil is one of the labiate flowers and is used as a spice and as a flavoring in cosmetics. In folk medicine it is used for flatulence, loss of appetite, feeling of fullness, as a diuretic and for throat infections.

On this piece woody debris from the soil of the Northern Black Forest National Park (Wilder See) one can see a beetle mite (Oribatida, Oppiella sp.). Mites are important recyclers of organic waste in and on the soil. They live in the upper soil layer up to 5 cm (maximum 10 cm) soil depth. Here they endure dryness and moisture. They can eat 10 to 20% of the annual stand waste. The cellulose and lignin are digested by microorganisms in the gut of the mites. The density of individuals on one square meter of forest ground can be 20,000 to 50,000 animals. This would correspond to a live weight of 8 to 20 kg per hectare. Mites (Acari) are a subclass of arachnids (Arachnida) in the arthropod tribe (Arthropoda).

This image shows the end of the fallopian tube close to the ovary. It consists of 20 to 30 fringes (fimbriae), some of which have grown together with the ovary. The fallopian tubes are 10 to 15 cm long tubes that connect the ovary to the uterus. They are lined with secretory cells and cilia (whitish) that create a current that carries the fertilized egg from the ovaries to the uterus.

The Radiolaria, also called Radiozoa, are protozoa of diameter 0.1–0.2 mm that produce intricate mineral skeletons made of silica, typically with a central capsule dividing the cell into the inner and outer portions of endoplasm and ectoplasm. They are found as zooplankton throughout the ocean, and their skeletal remains make up a large part of the cover of the ocean floor as siliceous ooze. Due to their rapid change as species, they represent an important diagnostic fossil found from the Cambrian onwards. Radiolarians have many needle-like extensions (of silica) supported by bundles of microtubules, which aid in the radiolarian's buoyancy. The cell nucleus and most other organelles are in the endoplasm, while the ectoplasm is filled with frothy vacuoles and lipid droplets, keeping them buoyant. The radiolarian can often contain symbiotic algae, especially zooxanthellae, which provide most of the cell's energy. The skeletons, or tests, of ancient radiolarians are used in geological dating, including for oil exploration and determination of ancient climates. This specimens origins from Mount Diablo in California and dates to the Eocene (34-56 million years ago).

Tardigrades (Tardigrada) - also known as water bears - form an animal strain within the moulting animals (Ecdysozoa). These eight-legged animals, most of which are less than a millimetre in size, are somewhat reminiscent of bears due to their appearance and their clumsy way of locomotion, which led to their name in the German-speaking world. Their scientific name (a combination of the Latin tardus 'slowly' and gradus 'step') also derives from their slow locomotion. They live worldwide in the sea, fresh water or in humid habitats on land; they are particularly common in moss cushions. One characteristic of the animals is cryptobiosis, a death-like state in which they can survive extreme environmental conditions. Tardigrades can feed on the contents of plant cells as well as predating small animals such as threadworms (Nematoda) or rotifers (Rotifera), which bite and suck them dry. Tardigrades usually reproduce sexually. However, some species also reproduce parthenogenetically, i.e. without the participation of males; in this case, the eggs of the females develop without fertilisation.

Cross-section through a root nodule of a clover with rhizobia (nitrogen fixating bacteria, bright blue) inside a cell (light red, core yellow). Rhizobia are bacteria that establish symbioses with legumes (Fabaceae). Rhizobia are able to convert elemental atmospheric nitrogen into nitrogen compounds (especially ammonia) and make them available to the plants. The bacteria get carbohydrates from the plants (succinate, malate and fumarate) from photosynthesis. Their ability to fix gaseous nitrogen makes legumes an ideal agricultural organism as their requirement for nitrogen fertilizer is reduced.

Small and important Oxygene Producers: Diatoms are unicellular algae that form a two-part shell made of silicon dioxide. These shells are interspersed with numerous pores that allow the algae to exchange substances with the environment and to move. Diatoms occur in fresh and salt water and are among the most important producers of organic matter in the ocean and oxygen in our atmosphere.

This mallow seed is from Indonesia. On one side, the seeds have long, strong hairs. These are believed to spread the seed over long distances by attaching to the fur or plumage of animals. Malva is a genus of about 25–30 species of herbaceous plants the family Malvaceae, the common English name is mallow. Malva are widespread throughout the temperate, subtropical and tropical regions of Africa, Asia and Europe.

This are capillarys from inside the renal corpuscle, the round objects are glomeruli. The regulation of the body`s water and electrolyte balance and the production of kidney hormones (prostaglandin, renin, erythropoietin, vitamin D3, kinin) takes place in the kidney. The fine vessels inside the renal corpuscle are responsible for the separation of the ureas (waste products of the metabolism) from the blood. To make this resin cast of the finest blood vessels visible, all surrounding tissue was removed.

The picture shows four prickly pollen grains (orange) extending their pollen tubes (bright brown) on the stigma of an ambrosia flower (whitish). This happens after the pollen has been delivered by by wind or insects. The pollen tube acts as a conduit to transport the male gamete cells from the pollen grain from the stigma to the ovules at the base of the pistil. These pollen tubes enable the sperm to pass through and thus fertilize the female ovules.