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Semester 2: M.Sc. Biotechnology Syllabus 2023-2024
History and microbial taxonomy Major discoveries related to the field of microbiology Antony Von Leeuwenhoek, Louis Pasteur, Robert Koch and Edward Jenner. Microbial taxonomy Bacteria, viruses, fungi, algae and protozoa, Microbial growth and metabolism Microbial growth Growth curve, factors affecting growth, Microbial metabolism- Methanogenesis, acetogenesis and auxotrophs
History and Microbial Taxonomy
Major Discoveries in Microbiology
The field of microbiology has evolved significantly since its inception. Key figures include Antony Von Leeuwenhoek, who is often called the father of microbiology for his work in microscopy and the first observations of microorganisms. Louis Pasteur's contributions to the germ theory of disease and vaccination helped lay the foundation for modern microbiology. Robert Koch's postulates established a systematic method for linking specific pathogens to specific diseases, while Edward Jenner's work on vaccinations initiated the modern era of immunology.
Microbial Taxonomy
Microbial taxonomy involves the classification of microorganisms into various groups. Bacteria, viruses, fungi, algae, and protozoa constitute the primary kingdoms of microorganisms. Each group is classified based on various characteristics, such as cell type, metabolic processes, and genetic makeup.
Microbial Growth
Microbial growth is the increase in the number of microorganisms in a population. The growth curve typically consists of four phases: lag phase, log phase, stationary phase, and death phase. Factors affecting microbial growth include temperature, pH, nutrient availability, and oxygen levels.
Microbial Metabolism
Microbial metabolism refers to the biochemical processes that occur within microorganisms. Methanogenesis is a process by which certain microorganisms produce methane as a metabolic byproduct under anaerobic conditions. Acetogenesis is another metabolic pathway, where different microorganisms produce acetate, typically from organic matter. Auxotrophs are mutants that require additional nutrients for growth compared to their wild-type counterparts.
Microbial culture, identification, and control Nutritional requirements for growth - Growth media and types, Pure culture techniques Serial dilution and plating methods, Staining methods - Principles and types of staining simple and differential, Microscopy principles and applications of Bright field, florescent and Scanning electron microscopes, Microbial growth control Physical Methods Heat, Filtration, Low Temperatures, High Pressure, Desiccation, Osmotic Pressure, Radiation Chemical Methods
Microbial culture, identification, and control
Nutritional requirements for growth
Microorganisms require specific nutrients for optimal growth. These nutrients include macronutrients such as carbon, nitrogen, and phosphorus, as well as micronutrients like vitamins and minerals. The formulation of growth media must consider these requirements to support microbial metabolism and reproduction.
Growth media and types
Growth media can be classified into different types based on their composition and purpose. These include: 1. Solid media - agar plates that allow colony formation. 2. Liquid media - broths for large-scale growth. 3. Selective media - inhibiting certain organisms while promoting others. 4. Differential media - distinguishing between different types of microorganisms.
Pure culture techniques
Pure culture techniques are essential for isolating specific microorganisms. Common methods include streak plating, spread plating, and pour plating. Each method aims to dilute microbial samples to achieve isolated colonies, enabling the study of individual species.
Serial dilution and plating methods
Serial dilution involves the stepwise dilution of a microbial sample to obtain a reduced concentration, facilitating the counting and isolation of viable cells. Plating methods involve inoculating diluted samples onto growth media to isolate individual colonies for further study.
Staining methods
Staining methods enhance the visibility of microbial cells under a microscope. There are two main types: 1. Simple staining - uses a single dye to visualize cell shape and arrangement. 2. Differential staining - uses multiple dyes, such as in Gram staining, to differentiate between cell types based on their structural characteristics.
Microscopy principles and applications
Microscopy is a technique used to visualize microorganisms. Key types include: 1. Bright field microscopy - uses visible light for basic imaging. 2. Fluorescent microscopy - employs fluorescent dyes to illuminate specific components. 3. Scanning electron microscopy (SEM) - provides detailed 3D images of surfaces at high magnification.
Microbial growth control
Control of microbial growth is crucial in laboratory and industrial settings. Methods include: Physical methods such as heat (autoclaving), filtration, low temperatures (refrigeration), high pressure, desiccation, osmotic pressure, and radiation. Chemical methods involve disinfectants, antiseptics, and antibiotics to inhibit or kill microbial growth.
Host microbe interaction and Epidemiology Human microbiome Skin, Gastrointestinal tract, Oral cavity, Lung. Microbial interaction Symbiosis, Mutualism, Parasitism, Commensalism and endophyte. Epidemiology of microbes causes, types and transmission of epidemic, endemic and pandemic diseases
Host microbe interaction and Epidemiology
Human Microbiome
The human microbiome consists of trillions of microorganisms that reside in various parts of the body, such as the skin, gastrointestinal tract, oral cavity, and lungs. These microbes play a key role in human health and disease, influencing metabolism, immune function, and protection against pathogens.
Skin Microbiome
The skin is home to a diverse array of microorganisms that contribute to its health. They provide a barrier against pathogens and assist in immune system training. Dysbiosis in the skin microbiome can lead to conditions such as eczema and acne.
Gastrointestinal Tract Microbiome
The gastrointestinal tract harbors a complex ecosystem that aids in digestion, nutrient absorption, and immune response. The gut microbiome is crucial for maintaining gut health, and alterations can lead to conditions like inflammatory bowel disease and obesity.
Oral Cavity Microbiome
The oral cavity contains a diverse microbiome that can affect oral health and systemic diseases. Oral bacteria contribute to conditions like dental caries and periodontal disease, and they can also influence overall health through the oral-systemic link.
Lung Microbiome
The lung microbiome is becoming an area of interest in understanding respiratory health. A balanced lung microbiome is important for protecting against infections, while dysbiosis may contribute to conditions like asthma and chronic obstructive pulmonary disease.
Microbial Interactions
Microbial interactions can be categorized into several types: symbiosis (beneficial for both), mutualism (both microbes benefit), parasitism (one benefits at the expense of another), commensalism (one benefits, the other is neither helped nor harmed), and endophytes (microbes that live inside plants, often providing benefits).
Epidemiology of Microbes
Epidemiology studies the causes, transmission, and control of diseases. It categorizes diseases as epidemic (spreading rapidly within a population), endemic (regularly found among particular people or in certain areas), or pandemic (spread across large regions or worldwide). Understanding the epidemiology of microbial infections helps inform public health interventions.
Microbial Diseases - General characteristics, pathogenesis, laboratory diagnosis and control measures of Pandemic and Epidemic diseases Tuberculosis, Cholera, Typhoid, COVID-19, AIDS, Malaria, Candidiasis
Microbial Diseases
Microbial diseases are illnesses caused by pathogenic microorganisms, including bacteria, viruses, fungi, and parasites.
These diseases often exhibit symptoms such as fever, inflammation, and the production of toxins.
They can be transmitted through various routes, including direct contact, air, water, and vectors.
Pathogenesis involves the process by which microorganisms cause disease, including adherence to host tissues, invasion, and evasion of the immune response.
Factors such as toxins, enzymes, and surface proteins contribute to the virulence of pathogens.
Isolating microorganisms from clinical specimens using specific growth media.
Utilizing light or electron microscopy to visualize pathogens.
Employing polymerase chain reaction techniques for genetic detection of pathogens.
Analyzing the blood for antibodies or antigens related to specific infections.
Immunization programs to prevent the onset of viral and bacterial infections.
Implementation of hygiene and sanitation practices to reduce transmission.
Utilizing antibiotics, antivirals, and antifungals to treat infections.
Mycobacterium tuberculosis
Airborne through respiratory droplets
Tuberculin skin test, chest X-ray, and sputum culture
BCG vaccine, public health measures
Vibrio cholerae
Contaminated water and food
Stool culture and rapid tests for cholera toxins
Oral rehydration therapy, sanitation improvements
Salmonella enterica serotype Typhi
Fecal-oral route
Blood culture and serological tests
Vaccination and improved sanitation
SARS-CoV-2
Respiratory droplets and aerosols
RT-PCR and rapid antigen tests
Vaccination, masks, social distancing
HIV
Blood, sexual contact, mother to child
HIV antibody tests, viral load testing
Antiretroviral therapy, safe sex practices
Plasmodium species
Anopheles mosquito bite
Microscopy, rapid diagnostic tests
Insecticide-treated nets, antimalarial drugs
Candida species
Opportunistic infection, not directly contagious
Culture or microscopy of tissue samples
Antifungal medications, maintaining good hygiene
Agricultural Microbiology Biological nitrogen fixation, free living, symbiotic nitrogen fixation, mechanism of Nitrogen, Biofertilizers- types and applications Rhizosphere, Rhizobium Azospirillum, Azolla, BGA
Agricultural Microbiology
Biological Nitrogen Fixation
Biological nitrogen fixation refers to the process by which atmospheric nitrogen is converted into ammonia by certain microorganisms. This process is crucial for agricultural productivity as it makes nitrogen available in a form that plants can use. Key organisms involved include free-living bacteria and symbiotic bacteria.
Free-Living Nitrogen Fixation
Free-living nitrogen-fixing bacteria such as Azotobacter and Clostridium exist independently in the soil and do not form symbiotic relationships with plants. They contribute to soil fertility by fixing atmospheric nitrogen, which is then available for uptake by plants, enhancing growth and yield.
Symbiotic Nitrogen Fixation
Symbiotic nitrogen fixation occurs when bacteria such as Rhizobium form a mutualistic association with leguminous plants. In this relationship, the plant provides carbohydrates to the bacteria, while the bacteria convert atmospheric nitrogen into ammonia, benefiting the plant.
Mechanism of Nitrogen Fixation
The mechanism of nitrogen fixation involves the enzyme nitrogenase, which catalyzes the reduction of atmospheric nitrogen to ammonia. This process requires energy in the form of ATP and is sensitive to oxygen, necessitating specific environments for the bacteria to thrive.
Biofertilizers
Biofertilizers are substances containing living microorganisms that promote plant growth by increasing the supply of essential nutrients. Common types include azospirillum, rhizobium, azolla, and blue-green algae (BGA). These organisms enhance nutrient availability, improve soil fertility, and can reduce the need for chemical fertilizers.
Types and Applications of Biofertilizers
Different types of biofertilizers include nitrogen-fixing bacteria (Rhizobium, Azospirillum), cyanobacteria (BGA), and green manure (Azolla). Applications include seed treatment, soil application, and incorporation into compost to improve soil health and agricultural productivity.
Rhizosphere
The rhizosphere is the region of soil surrounding a plant root where complex interactions between roots, soil, and microorganisms occur. It plays a critical role in nutrient cycling and influences plant health through various microbial activities, including nitrogen fixation.
Rhizobium
Rhizobium is a genus of nitrogen-fixing bacteria that forms root nodules in leguminous plants. The symbiotic relationship facilitates the conversion of atmospheric nitrogen into a form usable by plants, significantly contributing to sustainable agriculture.
Azospirillum
Azospirillum is a genus of free-living nitrogen-fixing bacteria that associates mainly with the roots of grasses. It enhances plant growth by improving nutrient uptake and promoting root development, making it a valuable biofertilizer.
Azolla
Azolla is a water fern that hosts symbiotic cyanobacteria (Anabaena) capable of nitrogen fixation. It is used as a biofertilizer in rice cultivation, enhancing nitrogen availability and soil health while reducing chemical fertilizer use.
Blue-Green Algae (BGA)
Blue-Green Algae, or cyanobacteria, are photosynthetic microorganisms that can fix atmospheric nitrogen. They are important biofertilizers in rice fields, contributing to soil fertility and providing a sustainable alternative to chemical fertilizers.
