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 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!

BACTERIA

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

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

THERMOPHILES

• Those that are classified as autotrophs are either photosynthetic, obtaining energy from sunlight or chemosynthetic, breaking down inorganic substances for energy .

Bacteria can be autotrophs or heterotrophs.

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 Bacteria

BOTULISM Clostridium botulinum

CHOLERA Vibrio cholerae

DIARRHEA (Traveller's Diarrhea ) Escherichia coli

FOOD POISONING Salmonella enteritidis

LEPROSY (Hansen’s Disease) Mycobacterium leprae

PEPTIC ULCER Helicobacter pylori

PNEUMONIA Streptococcus pneumoniae

TETANUS Clostridium tetani

TBERCULOSIS Mycobacterium tuberculosis

TYPHOID FEVER 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 Fungi

CANDIDIASIS (Infection of mouth and vagina) Candida

MENINGITIS (Severe form of infalammation of the membranes

covering the brains and the spinal cord)

Cryptococcus neoformans

PNEUMOCYSTIS (a form of pneumonia) Pneumocystis jiroveci

HISTOPLASMOSIS (A FORM OF LUNG INFECTION) Histoplasma capsulatum

ASPERGILLOSIS (Infection of the lungs and other organs of the body) Aspergillus

RINGWORM Tinea Corporis

ATHLETE’s FOOT Tinea Pedis

DANDRUFF Pityrosporum ovale

DISEASE-CAUSING FUNGI

VIRUSCome 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) Human immunodeficiency Virus (HIV)

CHICKENPOX Varicella Zoster Virus

COMMON COLD Enterovirus

INFLUENZA (FLU) 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.

• Influenza virus • AIDS virus

Different types of viruses

Different Shaped Viruses

Size

• Smaller than bacteria

• 20-300 nanometres (nm)

• A virus contains nucleic acid (DNA or RNA)

• Surrounded by a protective coat (capsid)

Structure of a Virus

Binding With the Host Cell

PROTISTS

• All protists have a nucleus and are thereforeeukaryotic.

• Protists are either plant-like, animal-like or fungus-like.

PROTOZOANS

are animal-like protists (heterotrophs) grouped

according to how they move.

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>.

AMOEBA

The first group is amoebae <ah-

me-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.

• 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 flagellapoking 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?

FLAGELLATES

• 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.

CILIATES

• The last of the Protozoans are Sporozoa.

• These are heterotrophic, parasitic and nonmotile.

• For example is plasmodium vivax.

SPOROZOANS

• Plant-like protists are autotrophs – they contain chloroplasts and make their own food.

• Algae are eukaryotic autotrophs.

• They produce much of Earth’s oxygen.

ALGAE and PHYPTOPLANKTONS

• are both plant-like and animal-like.

• Euglena are autotrophs since they make food from sunlight and

• Heterotrophs since they ingest food from surrounding water.

EUGLENA

• 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.

DIATOMS