Chestnut and the Motic Panthera U

While looking through my new stock of prepared slides, I came across this specimen, a section of a petiole of the Castanea sativa. The Castanea sativa or European chestnut is widespread in Europe and Asia, meanwhile also in other temperate zones. The chestnuts are consumed since ancient times by people. The tree can become very old.

It was not necessary to take multiple photos of the object and stack it. The coupe was cut perfectly flat. The section is stained according to the Wacker 3A procedure (Acridine red -Acriflavin - Astra blue).

Iodine, indispensable

For the photo, a tiny grain of iodine was applied over an object slide with a cover slip on top. After gently melting it over a spirit flame and then solidifying, a crystal structure appears, which can be seen with the help of polarization.

African mahogany Khaya ivorensis

Khaya ivorensis is the most important tree species that provides mahogany originating from Africa. This tree species can grow to a height of around 40 to 50 meters with trunks up to 2 meters thick. The basis of these trees is often buttressed. Khaya ivorensis prefers wet virgin evergreen forest. In Africa, this wood is traditionally used in canoe building. Different parts of the tree are important in traditional medicine and soap making. This noble type of wood is one of the most important species for wood plantations, because the trees grow quickly and produce high-quality wood that is often used where durability and beauty of the construction are important.

Crystals have been made explicitly visible on the photos using polarization. Crystals in plant tissues are generally waste materials and in some cases (amongst others) may also have a strengthening function.

© www.willemsmicroscope.com

Boost your resistance

At the time of the Corona crisis, many people resort to remedies to increase resistance to disease, such as vitamin C and Multi vitamin tablets. These, in this case foam tablets, contain many other substances besides the vitamins. Although the subject ‘vitamin C’ has been used many times in microscopy, it is still fun to view the crystals of these substances under the polarization microscope.

So, no sooner said than done, the tablets are now up for grabs at home anyhow. Dissolve a tablet in water, filter the solution, heat a few droplets of the solution on an object glass over a spirit burner in order to saturate it by evaporation. Let it crystallize patiently, put a cover glass on it and move it under the microscope.

Lumbriculus variegatus - The blackworm

Lumbriculus variegatus, more commonly known as a blackworm, is an oligochaete worm found in many freshwater habitats across Europe and North America. It is technically not microscopic, but very small and to see the details and internal anatomy, we have to use a microscope.

Blackworms are only about a millimeter in thickness, but they are able to reach a length of up to 10 centimeters. Blackworms eat things like microorganisms and decaying plant material. To digest its food, the worm has a dedicated digestive tract running down the center of the body. This is like a miniature version of the human digestive tract and works in basically the same way by squeezing ingested food through the tube with rhythmical massaging movements called peristalsis (see video further down).
Another clearly visible structure in the worm is its circulatory system. The animal lacks a true heart, but instead pumps blood through the blood vessels with several pairs of muscularized vessels able to contract and work as a heart.

How to avoid extreme highlights from reflecting surfaces

Optimize your illumination system. Extremely applicable in case of image documentation by a digital camera.

Reflected light is polarized light. This physical property is known by everybody who is doing serious photographies with a single lens reflex camera.

Motif: Landscapes, technical buildings, any kind of documentation for newspaper or book.
Solution: A rotatable polarization filter mounted in front of the objective.

Polarization filter of a reflex camera (source)

Rotate the filter until contrast is maximum, reflections are minimum. A new viewing angle requires a new adjustment.

Picture taken with Pol-Filter, interior visible vs Picture taken without Pol-Filter (source)

Tardigrades - Some of the toughest, and smallest, animals on earth!

Tardigrades are some of the smallest animals on the planet. Most are around 500 microns (half a millimeter), but newly hatched tardigrades can be 10 times smaller than that. And the biggest ones only reach about a 1.5 millimeters. Tardigrades are more commonly known as water bears. This is because of their bear like appearance when they waddle around looking for food. But, unlike a bear, tardigrades have eight legs which all end in several claw-like toes. Most tardigrades are herbivores and eat thing like algae and other plant material. However, not all tardigrades are grazers, some are hunters and eat things like bacteria, single celled organisms, rotifers and even other tardigrades.

Living tardigrade from the genus Ramazzottius.

Tardigrade from the genus Milnesium mounted in hoyer's medium.

Colorful microscopic crystals

Vitamin C (ascorbic acid) | Motic BA310E 4X | Moticam Pro S5 Lite | © My Microscopic World

A crystal is a solid where the individual molecules are arranged in a highly ordered three-dimensional structure like we see in grains of sugar and table salt. This is compared to when a substance is dissolved in a liquid and all the individual molecules are floating randomly around. If a liquid with a crystallizable substance is left to evaporate. The individual molecules will rearrange themselves and get bound to one another in a crystalline structure. Depending on which substance it is, both the micro- and macroscopic crystal structure will vary greatly.

Old but indispensable

A polarization microscope can be used to identify the mineralogical composition of geological materials in order to help reveal their origin and evolution. Some of the properties and techniques used include: refractive index, birefringence, Michel-Lévy interference color chart, extinction angle, conoscopic interference pattern (interference figure), Becke line test, wave plate etc.

About Polarization

Utilizing the polarization method in light microscopy reveals a specific kind of information about the sample. Applying this contrast method, we less often talk about structure size and shape, resolution power or even a specific staining. In case of transparent samples, polarization contrast in first instance has one subject in mind: the potential BIREFRINGENCE of the sample and its implications on a structural insight.

BIREFRINGENCE is a widespread phenomenon, found in nature as well as in man-made materials. Starch grains, fibers, crystals and minerals, plastic sheets and die cast components, the structural basis is always the same: embedded within an amorphous matrix, structures with an intrinsic geometric pattern cause an impact on the speed of light and its oscillating direction when sent through the sample.

Chemical cristals

Medicine in roots and tubers

Around 1600, Dahlia seeds from Mexico were transported for the first time to try them in Europe. In the beginning, there has been little note. Around 1800 there was more life in the brewery and the plant was pulled into bloom in the Botanical Gardens of Madrid. Later, the plant was seeded and grown in the Botanical Gardens of Berlin.

Sugar sweet colors

The beautiful colors we observe under the polarizing microscope have to do with the "optical activity" of - in this case - fructose.

Light is an electromagnetic wave phenomenon, in which the direction of vibration is perpendicular to the direction of propagation. An electric and a magnetic vector vibrate thereby at right angles relative to each other. In a 'normal' light, such as daylight, all directions of vibration are present at the same time. Polarized light, is light wherein only one direction of vibration in the beam is present.

Potatoes are everywhere

Potatoes contain starch in the form of typical large oval spherical granules; their size ranges between 5 and 100 microns. Under the microscope, the granules can be seen clearly in polarized light.

Potato starch – also known as potato flour – is extracted from potatoes. The cells of the root tubers of the potato plant contain starch granules (leucoplasts). To extract the starch, the potatoes are crushed and the starch grains are released from the cells. The starch is then washed out and dried to powder. Potato starch has been produced in the same basic way for centuries – actually even the ancient Incas knew how to make potato starch.

Rock from the depths of the earth

Basalt belongs to the group of igneous rocks. Igneous rocks are formed when hot liquid magma (lava) from the depths of the earth, is forced to the surface by volcanic forces and flows like a mudslide directly over the earth's surface, where it cools down and solidifies. Basalt is used in the road and hydraulic engineering in particular, as a result of its favorable mechanical properties.

Basalt as (geological) young volcanic rock, gets a fine-grained structure when cooling down relatively rapid. It is interspersed with small circular hollow vesicles. The color ranges from dark gray via gray-black to dark blue. Basalt is very solid and

The microscope objective - the key issue for best image performance

Different samples require different microscopes. This rule refers to the fact that an opaque, bulky sample with a reflective surface needs another treatment than a transparent, unstained smear from the cavitas oris. The microscope stand offers the necessary space for a correct positioning of the sample and all options for the appropriate illumination method.

 The microscope objective is an even more specific item. Here we talk about the required resolution power (= numerical aperture), but also about cover glass correction, immersion method and working distance.

1. The standard upright microscope for transmitted light is constructed for glass slides with a 0.17mm cover slip. This restriction is indicated on the objective sleeve:

Cover slip thickness indicated on Motic's Plan UC Fluor objectives

The cover slip has to be placed on top of the sample. A slight pressing of a dissecting needle will help to avoid too much embedding medium (water, etc.) between sample and cover slip. The embedding medium in this case works as an