Euglena - part plant, part animal

Cells with a nucleus are called true cells, or eukaryotes, which can be further subdivided into kingdoms like plant and animal. Plant cells and animal cells are different in their components and structure, but some organisms does not fit as neatly into these little boxes and can be tricky to place on ‘the tree of life’. One of these is the single celled organism euglena.

Euglena with clearly visible red eyespots

A beacon for sailors

In an earlier publication, photos have already been shown of a tree species that belongs to the Casuarina family. In this case, a photo was taken of the cross-section of a needle with a DAPI long-pass fluorescence filter, which gives a nice image.

The Club moss – an all-round talent for scientific education

The Club moss (genus Lycopodium) is a native plant of North and Middle Europe, also occurring in Russia, Asia, North America, even in the mountain areas of tropical Africa.

                        Lycopodium clavatum (source)                                                           (source)

Its dispersal units are spores, growing in kidney-shaped sporangia at the base of specialized leaves. These leaves are aggregated in club-shaped units terminating the upright shoots and give reason for the common name “Club moss”.

The spores are used since the Middle Ages for magic rituals (witches farina, flash powder, etc.), nowadays from fire-eaters, for artificial explosions in shows and in movies. This is because the spores contain up to 50% fatty oil, highly inflammable. It’s like “adding fuel to the fire” if you use them.

LYCOPODIUM SPORES FEATURES

The spores can be used for scientific education in multiple disciplines.

• Microscopy, Episode 1: In first instance the spores of Lycopodium with their reticulate surface (1st one from the right) are aesthetic samples with a marked three-dimensionality. For training the fine focus procedure on a transmitted light microscope, this is a good sample. Note the triangle on the surface (2nd one from the left) which indicates the original spore tetrad (Meiosis).

Mysterious crystal growth on tiny crustaceans

Crustaceans form a large group in the animal kingdom, and most are familiar with some of the larger members like crabs, lobsters, and shrimps. But many crustaceans are a lot smaller than those, and make up an important part of the food chain as food for fish and other larger animals. One of these planktonic species is daphnia magna, and with a size of 1.5 to 5 millimeters it is one of the largest in its family and just visible with the naked eye. However, it is not the daphnia itself we will focus on today. But a strange phenomenon that occurs on its body, as well as on a few other tiny crustaceans like it.

Female Daphnia magna carrying the next generation in a cavity.

Water worms

When searching for macro fauna in a small pool in the province of Limburg, The Netherlands, the worms on the video were found alongside many other organisms. These worms belong to the Oligochaeta, a subclass within the ringworm taxonomy. There are species that live in the soil on land and species that live in the water.

Oligochaeta are well-segmented worms and most have a large body cavity that is used as a hydro skeleton. Usually each segment has little bundles of chaeta or ‘bristles’ on the outside, The bundles can contain one to several hairs and contain muscles to pull them in and out of the body. This allows the worm to get a grip on the ground or mud while it nestles into it. When digging, the body moves peristaltically, alternately it contracts and stretches forward.

Stentors - some of the largest single celled organisms in the world

Stentors are trumpet shaped single celled organisms found in freshwater habitats like pods and streams. Due to their shape they are more commonly known as trumpet animalcules. Stentors are some of the largest single celled organism in the world, with the largest species reaching a size of up to two millimeters, and it is therefore possible to spot them in a water sample without a microscope. Stentors are ciliates, which mean that they move and feed with tiny hair-like projections called cilia. They have a large number of these cilia surrounding the mouth which creates a current of water carrying food particles for ingestion. In the opposite end they have a foot which is they use to adhere to a substrate.

Observe the classic trumpet shaped appearance and the clearly visible cilia surrounding the mouth.

Clematis vitalba, a dicotyle poisonous plant

Clematis vitalba is a perennial from the ranunculus family or Ranunculaceae. It is a dicotyle plant which can be seen from the regular concentric distribution of the vascular bundles in the cross section of the twig. It is a woody climbing plant that occurs in forests and scrubland on calcareous soils. It grows in light places in forests, forest edges, hedges, fences and wooded banks, scrubland in the dunes, along railways, along river dikes, floodplains and waterfronts.

Eudorina - a colonial algae

Eudorina is a genus of green freshwater algae. Each eudorina are multicellular colonies consisting of 16, 32 or even 64 individual cells held together by a gelatinous substance made of sugary proteins, or glycoproteins to be a bit more scientific. The individual cells in a colony are not much larger than our blood cells, and the entire colony is about the same size as the width of a human hair. The green color is due to the presence of large chloroplasts inside each cell used for energy production through photosynthesis.

Note the gelatinous transparent matrix surrounding each colony.

How to get sections from the finest objects: About razor blades, elder marrow and bottle corks

The first steps into science are not too difficult. If a microscope is at hand, the preparation of the sample is the key issue.

Nature gives us an easy entry. Egeria densa (Elodea densa) an American/Canadian waterweed, is an aquarium plant you can buy in every pet shop. A cheap and quick purchase.

Egeria Densa (Source)

The leaves are transparent as they only have 2 cell layers. Pull off one complete leaf from the stem and cut out a small portion. Place it onto a glass slide, add a drop of water and cover the sample with a cover slip.

© Sabine Lask, Heidelberg, (Germany)

© Sabine Lask, Heidelberg, (Germany)

Wormwood fluorescence

The photos we see here were taken from a Plescher prepared slide. Plescher fluorescence prepared slides are characterized by a distinctive, three-dimensional, deeply structured honeycomb structure. This is made possible by special, complex, gentle pre-treatment of the hand coupes made of living material that reproduce the sensitive cell contents surprisingly well. The conventional ultra-thin section technology with embedding in paraffin, does not provide the same detailed results. Plescher specimens impress with their specially developed Plescher staining with clarity and gloss, differentiated on a deep black background at 460 - 490 nm excitation wavelength. They are therefore generally ideal for photo stacking.