Microbes Are invisible to the naked eye, you need a powerful microscope to see them. Are everywhere around us, inside us, on us, in our food, in our homes, in the air we breathe and the water we wash in. Are mostly useful, but some are harmful Have been around for 3.8 bn years. Are vital for life on Earth.
What do Microbes look like? Magnified 1000 s of times and coloured using dye, we see -
Microbes exist in huge numbers In one single teaspoon of garden soil, there are over 100,000 microbes. In 1ltr of seawater, there are over 1bn microbes. On your hands there are more microbes than there are people in the world. There are so many microbes, that scientists have only named 0.5% of them. Microbes outnumber all other species and make up most of the living matter on the planet.
Microbes three types Bacteria strep bacteria Virus rotavirus Fungi mould
Bacteria Have three main shapes
BACTERIA Bacteria are prokaryotic and unicellular. Bacteria have cell walls. Bacteria have circular DNA called plasmids Bacteria can be anaerobes or aerobes. Bacteria are heterotrophs or autotrophs. Bacteria are awesome!
Endospore Bacteria can survive unfavorable conditions by producing an endospore.
Depending on the species, bacteria can be aerobic which means they require oxygen to live or anaerobic which means oxygen is deadly to them. Green patches are green sulfur bacteria. The rust patches are colonies of purple non sulfur bacteria. The red patches are purple sulfur bacteria.
METHANOGENS These Archebacteria are anaerobes. They make methane (natural gas) as a waste product. They are found in swamp sediments, sewage, and in buried landfills. In the future, they could be used to produce methane as a byproduct of sewage treatment or landfill operation.
EXTREME HALOPHILES can live in extremely salty environments. Most are photosynthetic autotrophs. The photosynthesizers in this category are purple because instead of using chlorophyll to photosynthesize, they use a similar pigment called bacteriorhodopsin that uses all light except for purple light, making the cells appear purple. the Great Salt Lake of Utah or salt ponds on the edge of San Francisco Bay
THERMOPHILES From hot springs and other high temperature environments. Some can grow above the boiling temperature of water. They are anaerobes, performing anaerobic respiration. Thermophiles are interesting because they contain genes for heat-stable enzymes that may be of great value in industry and medicine
Bacteria can be autotrophs or heterotrophs. Those that are classified as autotrophs are either photosynthetic, obtaining energy from sunlight or chemosynthetic, breaking down inorganic substances for energy.
Cyanobacteria You may have seen them as "green slime" in your aquarium or in a pond. can do "modern photosynthesis", which is the kind that makes oxygen from water. the first organisms on Earth to do modern photosynthesis and they made the first oxygen in the Earth's atmosphere.
What can bacteria do? We have learnt that bacteria do many good things, - such as decompose waste - give texture and flavour to food. - They give off oxygen when they eat. Half of all the oxygen in the world, comes from bacteria.
Bacteria that cause Diseases DISEASE BOTULISM CHOLERA DIARRHEA (Traveller's Diarrhea ) FOOD POISONING LEPROSY (Hansen s Disease) PEPTIC ULCER PNEUMONIA TETANUS TBERCULOSIS TYPHOID FEVER Bacteria Clostridium botulinum Vibrio cholerae Escherichia coli Salmonella enteritidis Mycobacterium leprae Helicobacter pylori Streptococcus pneumoniae Clostridium tetani Mycobacterium tuberculosis Salmonella typhi
FUNGI Eukaryotic Nonphotosynthetic (heterotrophic) Most are multicellular Most are microscopic molds or yeasts The study of fungi is known as MYCOLOGY.
Fungi Not just mushrooms athlete s foot, penicillin, and yeast. Yeast is used in bread making, and brewing
Structure of Fungi Filaments of fungi are called hyphae. The cell walls contain chitin. The MYCELIUM is a mat of hyphae visible to the unaided eye ( bread mold) Some hyphae may divided by cross sections called septa Septated Unseptated - coenocytic
Penicillin, an antibiotic, comes from molds of the genus Penicillium Notice the area of inhibition around the Penicillium.
DISEASE-CAUSING FUNGI DISEASE CANDIDIASIS (Infection of mouth and vagina) MENINGITIS (Severe form of infalammation of the membranes covering the brains and the spinal cord) PNEUMOCYSTIS (a form of pneumonia) HISTOPLASMOSIS (A FORM OF LUNG INFECTION) ASPERGILLOSIS (Infection of the lungs and other organs of the body) RINGWORM ATHLETE s FOOT DANDRUFF Fungi Candida Cryptococcus neoformans Pneumocystis jiroveci Histoplasma capsulatum Aspergillus Tinea Corporis Tinea Pedis Pityrosporum ovale
VIRUS Come in 1000s of different shapes and sizes. They hang about waiting to meet a host which they then invade, hijacking the host s cells. Beware the air you breathe and door handles!
viruses with only DNA/RNA + protein coat all are parasitic (they are considered living only when they are inside living cells) they cannot produce their own food
A virus is another microorganism that caused diseases. A virus is even smaller than bacteria. It must use a living cell to grow and reproduce. DISEASE Virus ACQUIRED IMMUNODEFICIENCY SYNDROME (AIDS) CHICKENPOX COMMON COLD INFLUENZA (FLU) Human immunodeficiency Virus (HIV) Varicella Zoster Virus Enterovirus Influenza virus GASTROENTERITIS Norovirus GANITAL CANCER/ CERVICAL CANCER Human papillomavirus HEPATITIS A Hepatovirus POLIOMYELITIS Poliovirus GERMAN MEASLES Rubella YELLOW FEVER Flavivirus
What is a virus? A virus is another microorganism that caused diseases. A virus is even smaller than bacteria. It must use a living cell to grow and reproduce. Virus can cause colds.
Different types of viruses Influenza virus AIDS virus
Different Shaped Viruses
Size Smaller than bacteria 20-300 nanometres (nm)
Structure of a Virus A virus contains nucleic acid (DNA or RNA) Surrounded by a protective coat (capsid)
Binding With the Host Cell
PROTISTS All protists have a nucleus and are therefore eukaryotic. Protists are either plant-like, animal-like or fungus-like.
PROTOZOANS The word protozoa means "little animal." They are so named because many species behave like tiny animals specifically, they hunt and gather other microbes as food. All protozoa digest their food in stomach-like compartments called vacuoles <vac-you-ohls>. are animal-like protists (heterotrophs) grouped according to how they move.
AMOEBA The first group is amoebae <ahme-bee>, 1. testate amoebae, which have a shell-like covering, 2. naked amoebae, which don't have this covering. Amoebae ooze along by means of pseudopodia (false feet) engulfing food as they go.
FLAGELLATES The second group is the Flagellates <flah-geh-lets>, are generally the smallest of the protozoa and have one or several long, whip-like projections called flagella poking out of their cells. Flagellates use their flagella to move. It is a flagellate in the intestines of termites which enable them to eat wood. Both organisms benefit..what kind of relationship do they have?
CILIATES The third group of protozoans are the ciliates from the phylum Ciliophora. These are generally the largest protozoa. They are covered with hair-like projections called cilia and they eat the other two types of protozoa as well as bacteria. Ciliates are found in every aquatic habitat.
SPOROZOANS The last of the Protozoans are Sporozoa. These are heterotrophic, parasitic and nonmotile. For example is plasmodium vivax.
ALGAE and PHYPTOPLANKTONS Plant-like protists are autotrophs they contain chloroplasts and make their own food. Algae are eukaryotic autotrophs. They produce much of Earth s oxygen.
EUGLENA are both plant-like and animallike. Euglena are autotrophs since they make food from sunlight and Heterotrophs since they ingest food from surrounding water.
DIATOMS are photosynthetic autotrophs with yellow and brown pigments. They have shells of silica. They make up a large portion of the world s phytoplankton which is Earth s largest provider of oxygen.