Without a doubt, bacteria are the most ancient creatures on Earth. They are involved at every stage of the cycle of substances in nature. Over the billions of years of their life, bacteria have taken control of processes such as fermentation, putrefaction, mineralization, digestion, and so on. Small, invisible fighters are everywhere. They live on various objects, on our skin and even inside our body. To fully understand their diversity, it may take more than one lifetime. Nevertheless, let's try to consider the main forms of bacteria, paying special attention to spherical unicellular organisms.
The kingdom of bacteria, or What microbiology studies
Wildlife is divided into 5 main kingdoms. One of them is the kingdom of bacteria. It combines two sub-kingdoms: bacteria and blue-green algae. Scientists often call these organisms shotguns, which reflects the process of reproduction of these unicellular organisms, reduced to "fragmentation", that is, division.
Microbiology is the study of the kingdom of bacteria. Scientists of this direction systematize living organisms into kingdoms, analyze morphology, study biochemistry, physiology,course of evolution and role in the ecosystem of the planet.
General structure of bacterial cells
All major forms of bacteria have a special structure. They lack a nucleus surrounded by a membrane capable of separating it from the cytoplasm. Such organisms are called prokaryotes. Many bacteria are surrounded by a mucous capsule that induces resistance to phagocytosis. A unique feature of the representatives of the kingdom is the ability to breed every 20-30 minutes.
Bacterial cells can have different shapes based on which they are classified:
- Cocci bacteria (spherical).
- Rod-shaped (bacillus bacteria).
- Twisted and curved bacteria (Vibrio and Spirilla).
- Chain-shaped bacteria (streptococci).
- Vinciform forms (staphylococci).
Let's take a closer look at the spherical bacteria, which have the common name cocci.
Globular (cocci): general information about bacteria
The term coccus came to microbiology from Latin. Its meaning is "spherical", "spherical". Although there is a version that the term is related to the Greek language, and its meaning is “grain”. In both cases, the name reflects the appearance of the microorganism. This means that the bacteria are spherical and have a rounded shape. Sometimes the cell can be somewhat elongated and approach an oval in shape, some organisms are slightly flattened laterally. All bacteria of this species are immobile and incapable of sporulation. Averagediameter of cocci - 0.5-1.5 microns.
Bacteria of spherical shape live in the soil, in the air, on products. Once in a favorable environment, the cell actively begins the process of reproduction. White, gray, yellow or red bacterial colonies form on the surface. In the process of reproduction, each spherical individual is split in two in any plane. After division, globular bacteria either remain independent or combine with other cocci.
Division into species
The group of spherical bacteria is heterogeneous. Inside it is divided into different types:
- gram-positive spherical micrococci;
- round paired diplococci;
- streptococci linked in a bacterial chain;
- forming tetracoccus square as a result of division;
- forming as a result of the division of the cube of sarcina;
- Spontaneously multiplying staphylococci.
All these cocci bacteria have their own characteristics, which are not only in the way of division. This requires a more detailed description for each species.
Features of micrococci
On the surfaces of micrococci are single individuals or irregular clusters. When placing a micrococcus on a dense nutrient medium, the formation of rounded smooth colonies of several colors (white, yellow, red) will be observed. The color depends on the pigmentation of the cell or the release of the colored product into the environment.
Micrococci areobligate aerobes. This means that they need oxygen to breathe. According to the mode of nutrition, these bacteria (spherical micrococci) are saprophytes, or facultative parasites. That is, they are able to obtain nutrients for development and growth from dead or decomposed tissues, or they feed on the tissues of another organism.
Micrococci are not pathogenic, that is, they do not disrupt the normal functioning, performance and integrity of tissues. Most of these microorganisms develop in the temperature range from 25 to 30 ° C. But some of them fall outside this range and are able to reproduce at a temperature of 5-8 ° C or do not die when heated to 60-65 ° C.
In the human body, micrococci are found on the skin, in the oral cavity, and in the respiratory tract. Occasionally on the genitals or conjunctiva.
Features of the globular bacterium diplococcus
Diplococci also belong to spherical bacteria. These spherical bacteria exist in pairs. It was this feature that became the basis for the appearance of the term "diplococcus". It is derived from the Greek word diploos, which can be translated as "double". Medicine has identified about 80 types of double bacteria. In the body, they are often protected by a capsule, which is a mucous formation no more than 0.2 microns thick. The capsule always has a strong bond with the cell walls of bacteria, it can be distinguished in smears of pathological materials. Diplococci are both Gram-negative and Gram-positive bacteria. They are pathogenic. Examples of globulardiplococci bacteria are gonococci, pneumococci and meningococci. They are the causative agents of gonorrhea, lobar pneumonia and meningitis.
Gonococcus has the status of the most pathogenic variety of diplococci. These pathogenic cocci are shaped like a double bean. But in some cases, they can lose their typical shape and form heaps of bacteria. To detect gonococci, a smear is taken and the number of leukocytes in the blood is determined. Gonorrhea is the most common sexually transmitted disease today. The disease is sexually transmitted.
Pneumococci excite not only croupous pneumonia, but also otitis media or sinusitis. The bacterium has a double lanceolate shape. It is motionless, and its size does not exceed 1.25 microns. Pneumococcus is a Gram-positive bacterium.
Meningococcus is a paired bacterium that looks like buns stuck together at the base. In appearance, it somewhat resembles a gonococcus. The sphere of action of meningococci is the mucous membrane of the brain. Patients with suspected meningitis must be hospitalized.
Staphylococci and streptococci: characteristics of bacteria
Let's consider two more bacteria whose spherical forms bind in chains or develop in spontaneous directions. These are streptococci and staphylococci.
Streptococci are numerous in the human microflora. When dividing, these spherical bacteria create beads or chains of microorganisms. Streptococci can cause infectious and inflammatory processes. Favorite places of localization - the oral cavity, gastrointestinal tract, genitals and mucous membranesairways.
Staphylococci are divided in many planes. They create grape bunches from bacterial cells. Can cause inflammation in any tissues and organs.
What conclusions humanity should draw
Man is too accustomed to being the king of nature. Most often, he bows only to brute force. But on the planet there is a whole kingdom in which organisms invisible to the eye are united. They have the highest adaptability to the environment and influence all biochemical processes. Smart people have long understood that "small" does not mean "useless" or "safe". Without bacteria at all, life on Earth would simply stop. And without careful attention to pathogenic bacteria, it will lose quality and gradually die out.
