Basic Microbiology Notes
Habit and Habitat Paramecium caudatum (Gr., paramekes=oblong+ L., caudata=tail) is a free-living organism which is one of the most common species of Paramecium having worldwide distribution. It is commonly found in freshwater, ponds, pools, ditches, streams, lakes, reservoirs, and rivers. It is usually found abundant in water containing decaying organic … Read more
Introduction The microbial community of bacteria, viruses, protozoa, and fungi with their collective genetic material present in the human gastrointestinal tract is known as the gut microbiome. The microbiome has a significant role in food and absorption of minerals, fabrication of vitamins, enzymes, amino acids, short-chain fatty acids, guarding against … Read more
The three-domain system was first introduced by Carl Woese in 1990 that is why its called Carl Woese’s Classification. This classification system also is known as the Six Kingdoms and Three Domains Classification because it divides the life forms into three domains and six kingdoms. The three-domains of Carl Woese’s … Read more
Toxin manufacturing is the potential of microorganisms known as toxigenesis. It is used by microbes especially by bacteria to induce disease. Bacterial toxins have two types on the basis of their chemical composition called endotoxin and exotoxin. Endotoxin are part of Gram-negative bacteria cell wall and exotoxin are secreted out … Read more
Differences between terminologies used in Microbiology Bacteroides and Bacteroids Bacteroides = It is a Gram-negative obligate anaerobic bacteria. Bacteroids= It is the morphological form of the nitrogen-fixing bacteria like Rhizobium which is irregular shaped and is present in the root nodules of legumes. Actinomyces and Actinomycetes Actinomyces = It is … Read more
Biosafety Level 1, 2, 3 and 4 The handling of pathogenic microorganisms is a highly challenging job due to the chances of contamination. Moreover, pathogens involve in causing the disease to a host. Bio-safety is a concept by which a person can take necessary precautions against infectious agents in a … Read more
Rapid Diagnostic Test vs Real-Time PCR (qPCR) There are several diagnostic tests that have been authorized for Emergency Use by the FDA for diagnosis of a wide range of infections. Notably, these diagnostic tests aim at identifying an infected individual from a non-infected person, using different working principles and duration … Read more
Bacteriophage- Structure, Classification, Application The virus that infects only bacterial cells (bacteria eater) Known as naturally abundant obligate intracellular parasites Niche- present where bacteria or archaea reside Diversity is more than the number of bacteria in nature Small size causes it to beyond the limits of light microscope resolution Smallest … Read more
Environmental Factors affecting Microbial Growth Apart from nutritional components growth of the microbes are also dependent on several environmental factors. These factors play an important role in understanding the growth pattern of a microbe. Apart from that, it is important to understand these factors especially in an industrial set up … Read more
Probiotic strains and their Human benefits What are Probiotics? Probiotics are living microorganisms that are intended to have health benefits when consumed or applied to the body. They are majorly found in milk products like yogurt, cheese, fermented foods, and food supplements. The Science of microorganisms has shown that most … Read more
Microbial Growth and Nutrition Micro and Macro Nutrients The microbial cell is made up of several elements such as carbon, oxygen, hydrogen, nitrogen, sulfur, phosphorus, potassium, calcium, magnesium, and iron. These are also known as macro elements or macronutrients because these elements are required in high amounts by the microbes. … Read more
GRAM NEGATIVE These are the characteristics of Gram-negative bacteria Cytoplasmic content is present means periplasm is present. The much thicker Peptidoglycan layer is present in gram-negative than gram-positive bacteria. The outer membrane of gram-negative contains LPS ( lipopolysaccharides) that contain, core polysaccharides, Lipid- A, and O- Antigen). Porins present in … Read more
Image Source: R-Biopharm AG 1. Direct Counts Counting Chamber Technique: In the direct microscopic count, a counting chamber with a ruled slide is employed. It is constructed in such a manner that the ruled lines define a known volume. The number of bacteria in a small known volume is directly … Read more
Microorganisms play an important role in causing infection and contamination. Therefore, Sterilization is an important technique in microbiology which helps to remove or destroy microorganisms from materials or surfaces. Common Definitions Sterilization It is the process by which an article, surface or medium is made free of all microorganisms either … Read more
Bacteria require several nutrients for their growth. Structural components such as cell wall and cell membrane restrict the entry of several molecules inside the cell. Therefore, the specific mechanism for nutrient uptake is highly important for the bacterial cell. Image Source: Dr. Kenneth Todar There are different transport mechanisms involved … Read more
Cell signaling and its types Cell signaling is referred to as the communication between various cells and molecules. The two most important part of cell signaling is a ligand and a receptor. A ligand is a molecule that is a primary messenger that binds to a specific receptor on the … Read more
Capsule, Flagella, Pili (Fimbriae), Glycocalyx (Slime Layer) Capsule The capsule is a gelatinous layer covering the entire bacterium. It is composed of polysaccharide, except in the anthrax bacillus, which has a capsule of polymerized d-glutamic acid. The sugar components of the polysaccharide vary from one species of bacteria to another … Read more
Effect of pathogens on plants What is Pathogen? A pathogen or infectious agent is a biological agent that causes disease or illness to its host. The term is most often used for the agent that disturb the normal physiology. The main pathogen are the virus, bacteria, and fungi. The physiological … Read more
VIVA Alert: Basic Microbiology with mnemonics Name one cluster shaped (grape-like) cocci? Staphylococcus aureus Name one chain shaped cocci? Streptococcus spp. What is the difference between Staphylococcus aureus and Streptococcus? S. aureus is cluster shaped and Streptococcus is chain shaped. S. aureus is catalase-positive and Streptococcus is catalase negative. Name … Read more