Thursday, 21 October 2021

Thousands of small lenses work together

Seen from the front, the head of the honeybee has a triangular shape, the head of the drone it is more round. On the head are the eyes, antennae and mouth parts. Important glands are located in the head and the main center of the nervous system: a nerve bud that serves as a brain.


Friday, 15 October 2021

A switching station

Ganglia are part of the peripheral nervous system. The peripheral nervous system includes all nerves outside the central nervous system (bundles of long nerve shoots with supporting cells) and small centers of nerve cells the ganglia.

A ganglion is a combination of mainly cell bodies (ganglion cells) with the nucleus of the nerve cell surrounded by cytoplasm without further shoots. This cell body with the nucleus as its center forms the metabolic center of the cell and is sensitive to stimuli. Ganglia function as switching stations for nerve impulses.

Wednesday, 6 October 2021

A pest from Africa

The southern green stinkbug (Nezara viridula) is a relatively new pest that originates from Ethiopia. The pest has a large number of host plants, but in horticulture this bug is mainly found in bell pepper cultivation. In the first instance, in The Netherlands, the southern green stink bug was only spotted at the end of the summer, but the bug has also shown itself earlier in the season in recent years.



Females lay around 30 to 130 eggs at a time. They do this in "glued together", yellow and white clusters at the bottom of the leaf. If they are just laid, they look like little pearls. Depending on the temperature, the eggs hatch after 4 days to 3 weeks and the empty eggs remain on the leaf. The nymphs initially stay together and do not yet affect the plant. They then go through different stages, each time shedding their skin, with each stage having a different appearance. In the fifth stage, the bugs begin to spread over the plant and eat it.

Wednesday, 29 September 2021

Ficus carica petiole and Wacker 3A staining

Vascular bundles can be seen very well in these cross-sectional views of a leaf stem of the fig tree, thanks to the Wacker 3A triple staining. This coloring is done with a mixture containing Astra blue, Acriflavin and Acridine red.


We see the vascular bundles that lie in an outer circle, characteristic of (eu)dicotyledonous plants. In monocotyledonous plants, the bundles are irregularly distributed over the cross section. The Xylem vessels lie on the inward side and the Phloem vessels on the outside of the outer circle. Between Xylem and Phloem we see the intravascular Cambium. Vascular bundles are also present in the inner basic Parenchyma.

Due to the good uniform thickness of the coupe and the fine quality of the Moticam S12 camera, the photos could be taken without stacking.

Tuesday, 21 September 2021

Sundew

Sundew or Drosera forms perfect rosettes to the ground and has red tentacles with a sticky, glittering droplet which is secreted by a gland. The flower owes its name to this. Small animals get stuck in the drop and are pushed by the moving tentacles to the leaf surface where they are digested.



Prepared slide by Lieder


Monday, 13 September 2021

Kahler's disease

The disease owes its name to the Austrian doctor Otto Kahler, who described the disease as one of the first. Kahler's disease, also called multiple myeloma, is a disease of the bone marrow caused by an uncontrolled proliferation of a certain type of white blood cells: plasma cells (also called plasmocytes). Plasma cells are responsible for the formation of antibodies under normal conditions.

The bone marrow is a spongy substance located in the interior of bones, especially the pelvis, sternum, ribs and vertebrae. Bone marrow plays a role in forming bones, but also in forming the cells of the blood: white blood cells (leucocytes), red blood cells (erythrocytes) and platelets (thrombocytes). The disease develops in one abnormal plasma cell, which divides uncontrollably and whose offspring also divides uncontrollably. Since they are all related, they only synthesize one specific type of antibody (or part of it). Since antibodies are proteins, the antibody produced is referred to as the "M protein" (from Myeloma protein). The name paraprotein is also commonly used for the M protein. When a specific piece (called “light chain”) of a paraprotein is found in the urine (or blood serum), it is called the Bence-Jones protein.

Friday, 10 September 2021

It grows on tree trunks

Dilated scalewort or Frullania dilatata grows mainly as a pioneer on trees with a moderately nutrient-rich bark. The species is somewhat drought-tolerant and can be found on free-standing trees, except in forests. Especially in full sun, the plants have their characteristic rust brown color. This moss experienced a decline in the last century due to air pollution, but is now common in almost all parts of The Netherlands. It is an attractive species, which is not easily overlooked in inventories. As a result, the distribution picture does suggest a greater number of occurrences than is actually the case: regularly there is only a single find per square section of land of 1 x 1 km.


Friday, 3 September 2021

Tempskya, growing millions of years ago

Tempskya is an extinct genus of tree-shaped ferns, the fossils of which have so far only been found in Cretaceous layers. The Cretaceous is a geologic period and system that spans 79 million years from the end of the Jurassic period 145 million years ago to the beginning of the Paleogene period 66 million years ago.


The stem-shaped structure of Tempskya is called "false stem" because it is formed by an entanglement of large numbers of stems and roots. The upward growing stems, which have a diameter of 2.5-10 mm, gave large numbers of roots (diameter about 1 mm) that grew downwards. They formed a felt-like mass around the stems. Because the stems branched regularly, a very solid whole was created. On a cross section of a trunk (see the images) the relatively large stems and the small roots can be seen.


 

Thursday, 26 August 2021

Which freshwater algae do we see?

In the video you will find some algae found in fens in the ‘Wortel Kolonie’ located in Belgium. The ‘Wortel Kolonie’ is a beautiful protected nature reserve with a complex of buildings that served as an asylum for vagrants long time ago. (Here you will find the information in Dutch, English, French and German).

This nature reserve contains a few shallow fens. On a summer day in July, some water samples were taken from two fens using a trawl net with a mesh size of 30 microns. Without examining these samples in depth, more than fifty different organisms, phyto- and zooplankton, were found. Only a few of them are shown in the video. In one of the algae we see a oogonium.

The names of the organisms in the video are deliberately omitted here, to give hydrobiology enthusiasts the opportunity to identify the organisms themselves.

Friday, 20 August 2021

Drill a hole before you can eat

The whelk or Buccinum undatum (Linnaeus, 1758) belongs to the snails (Gastropoda).

The whelk is a large, thick predatory snail with 7 or 8 turns. A deep seam runs between the turns. The mouth opening takes up almost half of the shell and ends in a sipho. On the surface there are horizontal ribs and clear vertical growth lines. Often there are also vertical ribs at the top of the shell. It grows up to 11 cm high and 7 cm wide. The whelk has yellowish-white with dark spots. Whelks washed ashore are often dark blue, because they have been lying on the bottom of the sea for a long time.