Flatworm digestive tract

The digestive tract of the flatworm, as shown here of a representative of the Dugesia genus, is not very complicated. 

This type of flatworm lives in fresh water. Flatworms absorb their food by mouth in the middle part of their lower body. A small tube shoots from the center of their body at the food and sucks it into the Pharynx. The fresh food is sent to and through the 'intestine', also known as the gastrovascular cavity. There the food is digested. It is spread on all parts of the worm, where the nutrients are needed for growth.

Mastocytoma dog

A mast cell tumor* (mastocytoma) is a potentially very malignant tumor of mast cells in the skin. This tumor is the most common skin tumor in dogs. It mainly occurs in the skin but not only there. A mast cell tumor can look very different. The tumor can be in the skin or under the skin. The presentation is usually like a solitary solid (sometimes soft) bump with a diameter of a few mm to as much as 10 cm. The overlaying skin is often alopecia (bald spot), erythematous (abnormal red), sometimes eroded or ulcerated (open wound). One should not squeeze the tumor; histamine granules* can be released (degranulate) This can cause an anaphylactic reaction, which means that the animal can get into shock. As mentioned, the tumor can be red in color, contain extra pigment or have the normal color of the skin.

As with all bumps on the skin, it is never possible to determine on the outside whether there is a tumor and what kind of tumor it is. Therefore, further investigation must also be carried out in the event of a suspicion of a mast cell tumor. This can be done by means of a FNAB (Fine Needle Aspiration Biopsy) or by means of a tissue biopsy. Cells are taken from the bump and these cells are assessed under the microscope (by a cytologist) as in this case. A FNAB gives a correct diagnosis in a large number of cases, but in all cases a tissue biopsy gives a correct and sometimes more extensive diagnosis.

Aeolosoma

Aeolosoma are very small annelid freshwater worms found all over the world. Even though these worms have been known for almost 200 years we do not know much about them. In fact, we know so little that there is still uncertainty on how to spell its name. Some will spell it aeolosoma, while others spell it aelosoma. 

Another mystery yet to be solved is which class of worm it is. Some place it in the same class as earthworms, the oligochaetes. Others place them in the polychaetes with bristle worms, and still others think they belong to their own separate class on the taxonomic tree of life. However it seems like the majority describes them as polychaetes.

Video showing aeolosoma at different magnifications with different microscopy techniques. 

Notice the almost complete clone in the back end of the worm

Wood - a fascinating material

 INTRODUCTION

Wood is a wonderful material. It embodies the beauty and the odor of forests, the ecology of a natural building material and the microscopic aesthetics of a complex 3-dimensional anatomical structure.

The secondary cell wall of plants, constructed of parallel cellulose fibers embedded in an amorphous matrix is impregnated with lignin and minerals as a stabilizing factor for altitude records, e.g. the “Tall Tree”, 112 Meter height, a Sequoia tree from the California National Park. Shrubs and herbs use this principle to a lesser extent.

About tree dimensions. Look for the human. (Source)

For the increasing lack of sand and therefore of concrete as a construction material architects today tend to wood as an alternative. Asian engineers are famous for their buildings made with the help of a bamboo scaffold.

Hong Kong building with bamboo scaffold. (Source)

In Europe, architects are increasingly working with natural materials to follow the ecological demands of their customers. They reinvent proven technology with wood as a basis. From a wooden house to a wooden skyscraper: a big step.

The concept for Germany’s first high-rise building in Germany made of wood. (Source)

WOOD MICROSCOPIC VIEWS

All attributes of wood can be derived from a microscopic analysis. The odor of a Christmas tree (resin channels!), the characteristics of furniture wood, the mechanical stability of timber. A tree trunk with its 3-dimensional structure needs 3 cutting planes to be fully understood: a cross section, a tangential cut, a radial cut.

• THE CROSS SECTION

The cross section is most easy to understand: 

How can I ensure a clean microscope?

INTRODUCTION

A microscope is a powerful scientific instrument. Science education in teaching institutes and universities is deeply depending on this instrument. Organizationally and financially justified, the students/users share the common instruments of a classroom.

Besides the well-known procedures to maintain the performance, in Corona times additional care is needed to avoid spreading the virus. Time to update our care recommendations.

IMPORTANT MICROSCOPE CONTACT AREAS

(1) Objectives

(2) Eyepieces

(3) Condenser

(4) Collector cover glass

(5) Glass slide including the cover slip

In the case the microscope is combined with a camera attached, you may find dirt.

(6) On the lenses of the camera adapter (C-mount)

(7) On the protection glass (IR filter) of the camera sensor

Attention: All inner surfaces of the optical elements are strictly taboo! Do not disassemble any part of your microscope for cleaning purposes. You only have access to the outer surfaces of these components. Disassembly will significantly affect the performance of your instrument and will void the terms of warranty. If you notice a malfunction in mechanics or electrics, please contact your nearest Motic supplier.

Just a beautiful preparation

Here we see the images of a beautiful preparation made by Mike Smith. The cross section trough the ovary of Buddleia globosa shows many details. Note that the ovary (and later the seed capsule) is covered in tangled hairs (stellate-tomentose) and how the base of the style is also hairy. The second fluorescence image shows this in detail.

Brought home from a trip to the Medina of Tunis

This tick appeared during unpacking travel luggage at home. The tick was neatly stored in a small bottle filled with alcohol and sent to the National Institute for Public Health and the Environment in the Netherlands, to have it identified. It is the Rhipicephalus sanguineus or Brown dog tick.

This species lives in countries with a warm climate in every continent and therefore also in countries around the Mediterranean Sea. Especially in Spain, France and Italy, people are regularly bitten by this brown animal.

Dogtooth Calcite

Calcite (CaCO3) is a mineral found in many different crystal forms. Dogtooth Calcite are calcite crystals that grow in a certain crystal form. This shape is long, pointed and resembles a dog's canines. This crystal shape comes in a wide variety of sizes, and of course the small ones are more common than the big ones. The growth of very large crystals, also called Dogtooth Spars, takes an extremely long time in undisturbed, calcite-rich water. Dogtooth Calcite crystals are quite common. Normally they are quite small, say a few millimeters.

In the photos we are introduced to the fluorescent properties of this mineral. Long pass fluorescence filter blocks were used for the exposure of the mineral sample: DAPI 375 nm excitation wavelength (UV) and MB 480 nm excitation wavelength (blue light).

Image stacking - for increased depth of field

A microscope is not only useful when investigating microscopic specimens. To see the fine details of insects and other larger specimens, a microscope is also extremely handy. However, the depth of field (DOF) is very shallow and only a small portion of the specimen can be in focus at each time. This is not due to bad objectives or microscope, but due to the high magnification. But this problem can easily be overcome by the use of an image processing method called focus stacking.

Illustration of the shallow depth of field.
The focus plane is at the top of the right eye and mouth

Right through a moss animals colony

Bryozoans, commonly known as moss animals, are a group of primitive animals that almost always live in colonies. There are about 5000 species, which occur in both fresh and salt water, at sites that are characteristic for them, such as ponds, lakes, ditches, streams and rivers, as well as water cellars of water companies. The colonies they form resemble plants. They are flat mats or branch-shaped colonies that are very variable in shape, and can grow to about 30 cm high. They need a hard substrate such as aquatic plants, reed stems, sticks, stones, cans, old boots and the like. Stones and especially wood seem more popular than glass and metal. They cling to any surface that provides a grip.

Here we see a cross section of a Plumatella colony that has formed around the stem of an aquatic plant. The colony is compact and zooids contact each other with their lateral walls. The large number and irregular arrangement of zooids means that almost every part of the animal is present in one place or another in the cross section.