What is microbiology- Lecture 1 Flashcards
What is microbiology?
study of things that cannot be seen with the unaided eye
What are some examples of microorganisms?
Viruses
Bacteria
Yeasts
Protists (protozoa)
Micro Algae
What are not microorganisms?
Fungi
Helminths
who was Antonie Van Leeuwenhoek?
In the 1680s he discovered both protists, bacteria and yeast with the first microscope at 50-300X magnification
Where do microbes thrive in?
Water, soil and animal bodies
What 2 ways can microbes come from?
- Spontaneous generation
- Arise from pre-existing organisms
What was spontaneous generation?
It was the earliest theory to do with “vital forces in the air” and was “proved” in experiments but was technically poor
How do microbes come from pre-existing organisms?
This was proved by Louis Pasteur in the 1800’s and was done by swan necked flasks and microbes on dust particles in the air
What are swan necks
narrow pipes that slow air flow. Slowed air flow can’t carry particles and this means the airborne microbes behave as particles
Who was Robert Koch?
In 1905 he did a study of Anthrax in cattle. The cattle had bacteria in their blood
(Bacillus anthracis). He grew the bacteria in laboratory (isolated them) and showed that they could pass the disease on to healthy cattle.
what were the 3 implications of the swan neck flask experiment?
- After Pasteur, widely accepted that decay is microbial and can spread easily.
- In Pasteur’s time infectious diseases were the major killers of man.
- Infectious diseases were known to spread easily, and it was possible that this property was due to a microbial aetiology
What were the main findings from Koch’s experiments?
- The microorganism is present in all cases of the disease.
- The microorganism is absent from healthy individuals.
- The microorganism can be isolated and grown in pure culture.
- The isolated microorganism can be reintroduced into a healthy host where it can cause disease.
- The same microorganism can be reisolated from the experimentally infected host.
For a liquid growth media to be grown, what is needed?
Bacteria + nutrients (broth) = growth
what changes the appearance of the broth?
Growth
What turns a broth cloudy (turbid)?
High numbers of cells and this makes it difficult to determine the composition of the bacterial population
Is a turbid broth culture composed of a single bacterial species or a mixture of species?
It can be from either
what is agar not?
a nutrient
What allows solid growth media to grow?
Bacteria + nutrients + solidifying agent = growth
what is agar?
a polysaccharide isolated from seaweed that is a liquid at 100oC and solid at 45oC
very difficult to digest for human/animal pathogens
Most widely used solidifying agent
What are colonies?
Growth identified by the appearance of visible clumps of bacterial cells. Colonies have characteristic sizes, shapes, colours etc. therefore different species can be easily separated from each other.
How does bacteria divide?
By binary fission and all the cells in a colony originate from a single cell and are identical.
What is bacterial colony morphology?
It is a full description of the appearance of bacteria and includes colony shape and size, margin, elevation, colour and texture
What is swarming motility?
it spreads over the surface of the plate and makes it difficult to separate from other species - e.g Proteus Vulgaris
Describe Staphylococcus aureus
- Colony shape and size: regular
- Margin (edge): entire
- Colour: yellowish
- Texture: mucoid
what is microbiology used in?
medical
disease
health
industrial
environmental
central to all processes
Are bacteria and yeast easy to grow?
yes and are easy to genetically manipulate
What are competitors?
They are harmful and are agents for human, animal, plant diseases and are agents of destruction, like food spoilage and decay
What are partners?
They are beneficial and are inhabitants central to the functioning of ecosystems and are found in normal human microbiota, like functional foods, the
intestinal tract for nutrient absorption, the intestinal tract for vitamin synthesis
and they allow immune stimulation
what are microbes used for in the food industry?
-lactic acid: preservative in cheese, yoghurt, etc.
-Ethanol: drinks
-CO2: baked goods
-organic acids: flavours in various fermented foods
Can microbes spoil food?
Yes, Up to 30% of all food produced in lost due to microbial spoilage!!
What are microbes used as in the pharmaceutical industry?
Antibiotics are produced by bacteria and fungi and inuslin, growth hormones, cytokines have been made by engineered bacteria and fungi
What is streptokinase?
An enzyme with medical applications and helps bacteria spread and breaks down blood clots
what are microbes used as in waste treatment?
They help with domestic and industrial waste and
remove organic material by reducing the impact on the environment (eutrophication of lakes). Microbes allow methane production from wastes, which can be used as an alternative energy source
What are microbes used for in biomedication?
they degrade synthetic pollutants, like chemical spills,
petroleum spills and the treatment of industrial waste.
What are microbes used for in mining?
Allows the recovery of minerals from certain copper and iron ores (ore leaching) and this is cheap and can reache difficult to mine deposits
How are microbes used in soil formation?
Used in the decay of organic matter and the global recycling of all major elements (C,N,O,S,P,H)
What is nitrogen fixation?
When inorganic N2 is converted to organic N (glutamine)
How are microbes used in rumen symbiosis?
used in the digestion of cellulose by ruminants
How are microbes used in disease control?
They are used in vaccines and antibiotics for animal diseases e.g. Newcastle disease, TB and food and mouth diseases
How are microbes used in plant improvement?
Bacteria and viruses can introduce genes (nitrogen fixation, disease resistance) into plants
What can microbes be used in?
- Food industry
- Pharmaceutical
- Waste treatment
- Bioremediation
- Mining
- Soil formation
- Nitrogen fixation
- Rumen symbiosis
- Disease control
- Frost resistance
- Plant improvement
What is aseptic?
A surface, object, product, or environment has been treated such that it is free of contamination
What are aseptic techniques?
Practices that allow for the preparation and maintenance of sterile nutrient media and solutions Aseptic technique is essential for the isolation and maintenance of pure cultures of bacteria.
What are pure cultures?
Only contain one type of microorganism
What were Koch’s main postulates?
Koch formulated a set of rigorous criteria for definitively linking cause and effect in an infectious disease.
- The suspected pathogen must be present in all cases of the disease and absent from healthy animals.
- The suspected pathogen must be grown in a pure culture
- Cells from the pure culture of the suspected pathogen must cause disease in a healthy animal
- The suspected pathogen must be reisolated and shown to be the same as the original
What are the universal properties of cells?
Metabolism (take up nutrients and expell waste) Growth (Nutrients from the environment are converted into new cell materials to form new cells) Evolution (cells evolve to display new properties)
What did Koch initaly use instead of agar?
Natural surfaces, like potato slices but he quickly developed more reliable and reproducible growth media, like agar, an algal polysaccharide with excellent properties
What are the harmful effects of microorganisms on man?
- Food poisoning
- Spoilage of food
- Reduce soil fertility
- Denitrification (nitrogen into free nitrogen)
What are the beneficial effects of microorganisms for man?
- Contribute to digestion
- Produce vitamin K
- Promote development of the immune system
- Detoxify harmful chemicals
- Essential for making many foods
- Clean up wastes
- Produce biofuels
