A colony is defined as a visible mass of microorganisms all originating from a single mother cell, therefore a colony constitutes a clone of bacteria all genetically alike. In the identification of bacteria and fungi much weight is placed on how the organism grows in or on media .
How would you describe colonies on blood agar?
Colonies typically are surrounded by a green, opaque zone . Streptococcus pneumoniaeand Streptococcus mitis are a-hemolytic (the picture in the middle below shows the a-hemolysis of S. mitis). If no hemolysis occurs, this is termed gamma-hemolysis.
How would you describe a colony in microbiology?
In microbiology, a “colony” is a group of bacteria, fungi, and other microorganisms grown on a solid agar medium . The cells plated on this medium grow to form a mass, which can then be duplicated for further use in the lab.
What is the most common bacterial colony form?
Form of the bacterial colony: – The form refers to the shape of the colony. These forms represent the most common colony shapes you are likely to encounter. e.g. circular , irregular, filamentous, rhizoid, etc.
How are the colonies identified?
Colony morphology is a method that scientists use to describe the characteristics of an individual colony of bacteria growing on agar in a Petri dish. It can be used to help to identify them. A swab from a bin spread directly onto nutrient agar . Colonies differ in their shape, size, colour and texture.
What are the two types of bacteria?
There are broadly speaking two different types of cell wall in bacteria, that classify bacteria into Gram-positive bacteria and Gram-negative bacteria .
What is the first step in identifying an organism?
Following isolation, one of the first steps in identifying a bacterial isolate is the Gram stain , which allows for the determination of the Gram reaction, morphology, and arrangement of the organism.
What does blood agar differentiate between?
Blood agar is a general purpose enriched medium often used to grow fastidious organisms and to differentiate bacteria based on their hemolytic properties .
What bacteria grows on what agar?
Nutrient agar provides these resources for many types of microbes, from fungi like yeast and mold to common bacteria such as Streptococcus and Staphylococcus . The microbes that can be grown on complex media such as nutrient agar can be described as nonfastidious organisms.
How can you tell the difference between a fungal and bacterial colony?
The main difference between bacterial and fungal colonies is that bacterial colonies are small, smooth or rough colonies with defined margins while fungal colonies are large colonies with a fuzzy appearance. Furthermore, bacterial colonies look wet and shiny while fungal colonies are powder-like.
Why do bacterial colonies stop growing?
These experiments indicate that bacterial colonies stop growing because metabolic inhibitors accumulate both within the colony and in the medium but not because of insufficient nutrients or fall in pH . When the medium is renewed and space is provided, colonies expand indefinitely.
What is an example of a colony?
The definition of a colony is a group of people who create a settlement in a distant land but remain under the governmental control of their native country or a group of similar animals that live together. An example of a colony was Massachusetts under British rule during the 17th and 18th centuries.
What are the 10 types of bacteria?
- Deinococcus radiodurans.
- Myxococcus xanthus. ...
- Yersinia pestis. ...
- Escherichia coli. ...
- Salmonella typhimurium. ...
- Epulopiscium spp. ...
- Pseudomonas syringae. Dreaming of a white Christmas? ...
- Carsonella ruddii. Possessor of the smallest bacterial genome known, C. ...
What are the 7 types of bacteria?
- Acidobacteria.
- Actinobacteria.
- Aquificae.
- Bacteroidetes.
- Caldiserica.
- Chlamydiae.
- Chlorobi.
- Chloroflexi.
How do you identify bacteria?
Bacteria are identified routinely by morphological and biochemical tests , supplemented as needed by specialized tests such as serotyping and antibiotic inhibition patterns. Newer molecular techniques permit species to be identified by their genetic sequences, sometimes directly from the clinical specimen.
What are 3 methods used to identify bacteria?
Traits that can be valuable aids to identification are combinations of cell shape and size, gram stain reaction, acid-fast reaction, and special structures including endospores
