Plasmodium fungus is one of the most amazing living organisms that exist on our planet. With his appearance, he was perplexed and at the same time frightened people from ancient times. No wonder he was called witch oil and wolf blood. In addition to its unusual appearance, the mushroom has another amazing ability - it knows how to move!
General information
Despite the fact that the plasmodium fungus, or mucus, has been known to people since ancient times, it still remains virtually unexplored. It was long attributed to the kingdom of the Mushrooms and was called myxomycetes, although it does not have a hard shell growing on top of the vegetative body. In addition, it differs significantly in the nature of nutrition and has a number of other features.
The name myxomycetes (translated from Greek - mucous mushrooms) in relation to these unusual organisms was first sounded in 1833. However, after a quarter of a century, the German botanist De Bari, who had been seriously studying them for several years, determined that plasmodiums had nothing to do with fungi, and most likely belong to the group of simple single-celled organisms. It was he who proposed to call these creatures Mycetozoa, that is, mushroom animals, or true myxomycetes.
Habitat
The plasmodium fungus is distributed practically throughout the world. It can be found even in deserts, among the snows and in the highlands. However, some species of these creatures, especially those that live in the tropics and arid areas, have very limited ranges. A large variety of plasmodiums can be observed in the temperate zone with its broad-leaved forests, as well as in the Mediterranean.
Some of the species can be seen only in the summer, while others are found, starting from early spring and ending in late autumn. The development of these fungi also occurs seasonally. The types of mucus cells, like the other lower forms of life, are determined by the form that their fruiting body has. Some might think that the plasmodium mushroom is edible. However, it is not. Slug is poisonous, and this scares away not only insects, but also small mammals.
Substrates
Most species of myxomycetes prefer to settle in the remains of rotting trees or in fallen leaves. Against the background of their fruiting bodies, plasmodiums are almost always clearly visible. It is not surprising that they appear in most of the work of mycologists, who mainly describe species associated specifically with these substrates.
Those organisms that live on the excrement of herbivores, as well as on the bark of growing trees, are much less studied. This is because the size of their sporophores is very small, and therefore it is extremely difficult to notice such species of myxomycetes in nature.
It is worth noting that plasmodium is a fungus (photo in the article), which in most cases is not tied to any one type of substrate. However, exceptions to the rules do occur. Some myxomycetes, for example, the genus Cribraria, prefer the bark of coniferous trees. There are also mucous membranes whose sporulation most often occurs on green or last year's fallen leaves, growing stems or mosses.
Propagation method
Like algae, the plasmodium fungus begins with spores. A germ cell emerges from it. If its environment is sufficiently moist, then it takes on the form of mixoflaggellate, that is, it becomes similar to an infusoria with two flagella of different lengths. It is the shoots that help these organisms swim freely in water.
If moisture is not enough, then a mixameba is formed from the spore. Interestingly, the above forms can interact with each other and are able to flow into each other. In addition, they have a haploid set of chromosomes, which means that the mucus has germ cells. In the process of their replication, a zygote arises, after which a tiny mixoflaggellate or mixameba begins to turn into a vegetative body - a unicellular organism in which nuclei divide very quickly. As a result, the cell rapidly grows and secretes mucus, while acquiring a color. Thus a small predatory organism is born, which subsequently forms the plasmodium fungus.
Description
True myxomycetes have a leading fan-shaped front and a network of branched cords (tubes), similar to blood vessels. At the stage of plasmodium formation, it becomes visible without any magnifying devices. At this stage of its development, it is a kind of unicellular mass, painted in yellowish color. The more favorable the environment for him, the larger he will grow.
This organism is often compared to an insatiable predatory monster that absorbs everything in its path. And this is true, since as it follows, it captures and absorbs various bacteria, spores of fungi, yeast, and even microscopic animals. The plasmodium fungus moves along the substrate, while simultaneously increasing in volume, and envelops food like an amoeba. In this case, the body forms the so-called nutritious vacuoles, in which it releases special digestive enzymes. After this, all the necessary substances are absorbed. This is the process of phagocytosis.
Being in the plasmodium stage, the mucus is amazing in size: this unicellular creature can reach 30 cm in length and 3-5 cm in thickness! An absolute world record was also recorded - one plasmodium cell Physarum polycephalum grew to such a size that it occupied an area of 2 m².
Movement process
The walking plasmodium mushroom inside its body has a kind of muscle - myosin and actin strands, which reduce the adjacent cytoplasm, thereby creating a pulsation and the possibility of its overflow. So there is a movement of this organism. Crawling along the substrate, it can move at a speed of up to 1 cm per hour.
It happens that there is not enough moisture in the environment, so plasmodium tends to solidify, harden and eventually turn into sclerotia. Sometimes it breaks up into several macrocysts, which are a fairly strong shell with several nuclei inside. Remaining in this condition, the body can exist for several years in a row, but when the state of the environment becomes favorable, each of the macrocysts will become a new plasmodium.
Amazing features
Plasmodia have a certain semblance of chemical instinct, because, being close to food, they will purposefully move in her direction. It is known that at some period of their life, their negative phototaxis changes to positive, and mushrooms from a moist environment begin to creep out to the surface, striving for sunlight. Most likely, this occurs during the period of their final ripening and intensive formation of spores.
Another interesting fact is that when two plasmodia of the same species meet, they "merge" together, thus forming a common organism. In a mature state, their plasma begins to condense in places and form fruiting bodies. They quickly develop and increase in size, since inside them there is a process of nuclear fission with the formation of haploid spores. After some time, the protective membrane of the periderm bursts, and the spores of the mucus are spread by the wind. But this only happens under favorable conditions. If the state of the environment does not fit them according to any criteria, then spores can exist for more than seventy years, while maintaining its ability to germinate.
Experiments on Mucus
A group of Japanese scientists decided to observe plasmodiums, since they are quite easily cultivated in laboratory conditions. They conducted an experiment on the speed of movement of the mucus, while changing the humidity of the environment. When the air became dry, plasmodium slowed down. Based on this, scientists investigated the effect of periodic exposure on the body, blowing it with dry air with an interval of one hour. Soon plasmodium began to slow down in advance. He seemed to be expecting the beginning of another impact. Having done such an experiment, the scientists decided that the slimes possess a semblance of memory.
Other studies were carried out, which determined that plasmodiums can solve simple problems, for example, to find the shortest path, going from one point of the maze to another. I must say that these experiments are of great importance, since they lead to an understanding of the behavior of these primitive creatures and the history of their evolution.