Bacteria Actinomycetes Yeast Description of colony characteristics of molds

Comparison of colony characteristics:

Bacteria: moist, viscous, and easily provoked.

Actinomycetes: dry, wrinkled, difficult to provoke, small colonies, mostly pigmented yeasts: moist, viscous, easy to provoke, bright surface, larger and thicker than bacterial colonies:

The hyphae are slender, the colony is loose, fluffy, spiderweb-like, cotton-wadding, no fixed size, shiny, and not easy to provoke.

1. Differences.

1. The bacterial colony is gelatinous, the surface is smooth and moist, and the combination with the medium is not tight, easy to pick, and the positive and negative colors are consistent. susceptible to provocation by inoculation rings; Cocci form raised colonies; Flagellar bacteria often form colonies with irregular edges; The surface of the colony with the capsular is more transparent, and the edges are smooth and neat; Dry wrinkles on the surface of the colony with spores; Some colonies of pigment-producing bacteria also show bright colors.

2. Actinomycetes colony grows radially on the solid medium, dense, hard, wrinkled, not easy to pick up with a needle, and opaque. When the spores are ripe, the surface is powdery, dry, and often has an earthy smell.

3. The mold colony is large, composed of hyphae with loose villous, flocculent or spider web, some have no fixed size, extend to the whole medium, produce pigment, and the colony has color.

4. Yeast colonies are similar to bacterial colonies, but larger and thicker than bacteria, opaque, smooth, moist, viscous, easy to pick up with needles, and mostly milky white.

2. Reasons. The characteristics of colonies are closely related to the morphological and structural characteristics of microorganisms.

For example, bacteria and yeasts do not form hyphae, and their colonies only grow on the surface of the solid medium, which is not tightly bound to the medium, and can be picked up with inoculation tools; However, most of the actinomycetes and molds are differentiated into vegetative hyphae and reproductive hyphae, and the vegetative hyphae absorb nutrients deep into the culture medium, which has the characteristics of tight binding with the culture medium and not easy to provoke.

Bacterial colonies are generally gelatinous, smooth and moist surface, not tightly bound to the medium, easy to pick, and the color is consistent.

Actinomycetes colonies are generally round, flat or with many wrinkles, and under light microscope, there are radial actinomycelium hyphae around the colonies;

The colony characteristics of most yeasts are similar to those of bacteria, but they are larger and thicker than bacterial colonies, the surface of the colonies is smooth, moist, viscous, easy to provoke, the texture of the colonies is uniform, the color of the front and back sides, edges, and ** parts are very uniform, and the colonies are mostly milky white, a few are red, and some are black;

The mold colony is large in morphology, dry in appearance, opaque, loose or tight in shape, with slender hyphae, loose colonies, and fluffy and cobwebs.

1. Bacteria are prokaryotes, and their forms are basically globular, rod-shaped and spiral-shaped; After Gram staining, it can be divided into Gram-positive bacteria and Gram-negative bacteria; Its general structure includes cell wall, cell membrane, cytoplasm, nuclear region, and special structures include flagella, sexual fili, glycocoat, spores, etc.; The colonies are generally moist, smooth, transparent, viscous, easy to pick, uniform texture, and the color of the front and back of the colony or the edge is consistent with the ** part.

2. Actinomycetes are prokaryotes, with filamentous branches and a very fine hyphae in diameter (less than 1 micron); Actinomycetes are mainly composed of hyphae, which can be divided into aerial hyphae and intrabasal hyphae, and the aerial hyphae mature and differentiate into spore filaments, producing clusters of conidia; Actinomycetes can be divided into the most common Streptomyces spp., Nocardia spp., Small Monospora spp., Streptomyces sporangia spp., Touring Actinomyces spp., etc.; The colony is dry, opaque, the surface is dense and velvety, there is a thin layer of colored "dry powder" on it, the colony and the medium are tightly connected, it is difficult to pick, the color of the front and back of the colony is often inconsistent, and the agar plane at the edge of the colony is deformed.

3. Yeast is a eukaryotic organism with globular, oval, columnar, etc. The structure consists of cell wall, cell membrane, cytoplasm, nucleus, vacuole, mitochondria, bud body, etc. Its colonies are similar to bacteria, but larger and thicker than bacteria, thicker in appearance, less opaque, and mostly milky white in color, a few are red, and some are black.

4. Molds are eukaryotes, which are fungi with developed mycelium and do not produce large fleshy proton body structure; According to the presence or absence of a septum in the hyphae, it can be divided into non-septal hyphae and septal hyphae; Structurally, it is divided into vegetative mycelium and aerial mycelium, and the vegetative mycelium has false roots and suckers that absorb nutrients, creeping branches that extend their functions, and attached cells and attachment branches that attach to them. The colony morphology is large, the texture is loose, the appearance is dry, opaque, showing loose or tight spider web, fluffy, cotton wool or felt-like, the connection between the colony and the medium is tight, it is not easy to pick, and the color and structure of the front and back of the colony, as well as the color and structure of the edge and the center are often inconsistent.

The morphological characteristics of the colony of <> yeast are similar to those of bacteria, but they are larger and thicker than bacteria, moist, smooth surface, mostly opaque and viscous, and the color of the colonies is monotonous, most of them are milky white, a few are red, and some are black. Yeast grows on the surface of solid medium, easy to pick up with a needle, and the colony texture is uniform, and the color of the front, back and ** is consistent with the edge. Yeast colonies that do not produce pseudohyphae are more raised and have very rounded edges; Yeasts that form a large number of pseudohyphae have flatter colonies with rough surfaces and edges.

The colonies of actinomycetes are made up of mycelium. It is generally round, flat or with many wrinkles, and when viewed under a light microscope, there are radiating hyphae around the colony. The general characteristics are between molds and bacteria, and can be divided into two categories depending on the species:

1. It is a colony formed by a strain that produces a large number of branched and aerial hyphae. Colonies of Streptomyces are representative of one type. Streptomyces hyphae are fine, slow growing, branched and intertwined, so the colonies formed are dense in texture, dense on the surface or firm, dry, wrinkled, and the colonies are small and do not spread.

2. Colonies are formed by species that do not produce a large number of mycelium, such as the colonies of Actinomyces nocardii, which have poor adhesion and a powdery structure, and are crushed when picked up with a needle.

Population diversity

With the continuous improvement of human ability and means to understand actinomycetes, more and more actinomycete species have been discovered and described. So far, about 2,000 species have been effectively described, of which more than 500 species of Streptomyces are generated, accounting for a large proportion.

Therefore, Streptomyces is also known as a common actinomycetes, with a routine detection rate of 95% of actinomycetes, while the routine detection rate of other types of actinomycetes accounts for only about 5%, and is known as a rare actinomycetes. According to statistics, the species of actinomycetes isolated in nature are only the actual species.

The above content reference: Encyclopedia - Actinomycetes.

Yeast is a class of single-celled fungi known for their use in winemaking, fermentation, and baking. Yeasts have some unique characteristics, for example, they are unicellular and usually grow in the form of colonies that have unique characteristics. Morphological characteristics of yeast colonies.

The morphological characteristics of yeast colonies include their color, shape, texture, etc. Generally, yeast colonies are white, creamy, off-white, or light pink in color, but there are also strains that may have bright colors, for example, red, orange, brown, etc. Yeast has round, oval, oval, etc., and the size is between microns and tens of microns.

Yeast colonies are mostly round or irregular in shape, soft in texture, smooth on the surface or with small granular protrusions.

Brigade shouts growth characteristics of yeast colonies.

The growth characteristics of yeast colonies include their growth rate, growth mode and surface characteristics. Yeast usually grows slowly, taking days to weeks to form larger colonies or towns. Yeast colonies grow in two ways:

One is planar growth, that is, the colony is planar on the surface of the medium, and the diameter gradually expands, but the thickness is not obvious. The other is raised growth, in which the colony appears as a round or irregular bulge on the surface of the medium, and gradually thickens over time. In addition, the surface of yeast colonies is usually characterized by smooth, moist features, sometimes with small, depressed or undulating granular protrusions.

Conditions for the formation of yeast colonies.

Yeast colony formation is influenced by a variety of factors, chief among which are factors such as the type of medium, temperature, humidity, and oxygen content. The type of medium plays a crucial role in the formation of colonies, and it is common to choose a liquid or solid medium with the right amount of sugar, amino acids and trace elements. Temperature, humidity and oxygen content are also important factors influencing colony formation.

Different yeast strains have different requirements for these factors, so it is necessary to choose the appropriate culture conditions according to different strains.

In conclusion, yeast colonies have unique characteristics and morphological characteristics, and different strains have different colony morphology and growth characteristics. In general, understanding the morphological characteristics of yeast colonies and their formation conditions can provide an important reference for the application and research of yeast.

Bacteria and yeasts do not form compound hyphae, and their colonies only grow on the surface of the solid medium, which can be picked up with DU inoculation tools, that is, they are not tightly bound to the culture DAO base. However, most of the actinomycetes and molds are differentiated into vegetative hyphae and reproductive hyphae, and their vegetative hyphae are deeply absorbed in the culture medium, so they have the characteristics of tight binding with the culture medium and not easy to provoke.

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The main component of the bacterial cell wall is peptidoglycan, also known as mucopetide. Actinomycete cell walls contain alanine, glutamic acid, glucosamine, and muramic acid. The main components of yeast cell wall are polysaccharides [dextran (30%-34%) and mannan (30%).

In addition, lipids, proteins 6%-8%. Fungi (molds) have a cell wall that contains chitin and also cellulose. Chitin is a glucosamine-containing polysaccharide that is the main component of animal bones such as insects, and plant cells do not contain chitin.

Bacteria and actinomycetes are prokaryotes, the main components of the cell wall are peptidoglycan, yeasts and molds are eukaryotes, and the cell wall components are cellulose, etc., so the enzymes used to obtain their protoplasts are definitely different, peptidase and cellulase can be used respectively.

Comparison of colony characteristics:

Bacteria: moist, viscous, and easily provoked.

Actinomycetes: dry, wrinkled, difficult to provoke, small colonies, and many pigments.

Yeast: moist, viscous, easily provoked, with a bright surface, larger and thicker than bacterial colonies.

Mold: The hyphae are slender, the colonies are loose, fluffy, spiderweb-like, cotton wool-like, no fixed size, shiny, and not easy to provoke.

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