Chapter 18 Monerans

• The Bacteria are organisms in this kingdom

• Bacteria are classified by their morphology and physiology.

• Bacteria are noted by their shape

Examples

Cocci – roundBacilli – rodSpirilla – spiral

other prefixes

diplo – two

strep – chain

staph – bunches

• Domains Archaea and Bacteria

• Bacteria are are sometimes classified into two Kingdoms: Archaebacteria and Eubacteria

• Archaebacteria/Archaea– adapt to harsh conditions

Ex- methanogens, halophiles, thermophiles

Methanogen

• They are common in wetlands, where they are responsible for marsh gas, and in the guts of animals such as cows/sheep and humans, where they are responsible for the methane content of belching in ruminants and flatulence in humans.

Halophiles

• Halophiles can be found anywhere with a concentration of salt five times greater than the salt concentration of the ocean, such as the Great Salt Lake in Utah, Owens Lake in California, the Dead Sea

Thermophiles

• Thermophiles thrive at relatively high temperatures,

between 45 and 80 °C (113 and 176 °F) • Hot springs of Yellowstone

• Eubacteria/Bacteria - free living soil, water and some infect organisms and produce disease

• small in size, large kingdom

Ex – Lyme's, Syphilis, Typhus, Leprosy, MERSA, TB, Yersinia Pestis, Tetanus, Botulism,

Pneumonia, Chlamydia, Salmonella, Cholera

Yersinia Pestis

• This bacterium can be transmitted to humans, usually by a vector such as fleas to lymph nodes that swell. In untreated people this may become dark or a black color. This type of plague is termed bubonic plague. The bacteria can spread into the bloodstream and eventually infect other organs.

Nutrition

• How do bacteria obtain their energy ?

Heterotrophs – saphrophytes feed off the dead Autotrophs – photoautotrophs use photosynthesis

chemoautotrophs – are nitrogen fixing bacteria

Nitrogen fixing bacteria

Structure of e coli bacterium

DNA – 1 chromosome

Cytoplasm/Cell wall/ Cell Membrane

Flagellum - locomotion

Pili – helps attach to other bacteria

Ribosomes- makes protein

Capsule – surrounds, carb. layer protects

plasmid – small ring of DNA, has genes

Endospore – if conditions are harmful this process encases DNA and some cytoplasm, the bacteria will lay dormant

Harmful conditions - dry

250 F to kill the endospore

Bacterial Respiration

Obligate anaerobe – can’t survive with oxygen

Obligate aerobe – needs oxygen

Facultative anaerobes – can live with or with out oxygen

Almost all animals, most fungi, and several bacteria are obligate aerobes. Most anaerobic organisms are bacteria

Halitosis - is caused by anaerobic bacteria. Known individually as anaerobes, these bacteria live in environments typically devoid of

oxygen

Reproduction 18-5

Can occur every 15-20 minutes

Asexual – Binary fission

DNA replicates, copies moves toward cell membrane, divide out evenly into two identical cells

Sexual reproduction

• conjugation

• Pili attach a portion of the DNA passes across the pili to the other bacterium

• Genetic diversity

Diseases caused by bacteriaPathogens – disease causing

Diseases are caused by Toxins – poisonous substances secreted, or left by dead bacteria

disrupts metabolism

Gram stain - a series of dyes that turn violet or red-pink according to the chemistry of the cell wall

2 types …

a. endotoxins – gram -, red stain, more complexb. exotoxins – most gram + , purple stain, secretes toxins,

simpler

Gram – = endotoxin, protected peptidoglycans, more resistant to antibiotics

Antibiotics - Alexander Fleming1929 mold fungus penicillium notatumconquered syphilis, gangrene and tuberculosis

inhibits bacteria enzymes

Most comes from the soil

Importance of Bacteria 18-6

Fermentation processes, much as brewing, baking, cheese and butter manufacturing

Using biotechnology techniques, bacteria can also be bioengineered for the production of therapeutic proteins, such as insulin, growth factors, or antibodies

E. Coli that lives in the human large intestine synthesize vitamin B and release it for human use

Microbial mining in which bacteria extract minerals such as copper

Hot Zone What do you remember ?

• Is ebola alive ?

• What does it look like ?

• What does it cause ?

• Where is it found ?

The Viruses

Virus characteristics

Viruses can’t be seen with the eye use an electron microscope

Most viruses that have been studied have a diameter between 10 and 300 nm

Viruses are not in a Kingdom why ? Not living

Viruses are classified by DNA or RNA

Bacteriophage• Viruses are intracellular parasites• Must invade to live and cause harm

• Bacteriophage virus attacks bacteria• Made of a protein coat and nucleic

acid

How viruses are spread

1. by air, dust or body fluids… mono, herpes, common cold, flu, SARS, measles, mumps, chicken pox, small pox (extinct), ebola ?

2. contaminated food or drink …. Hepatitis A, Norwalk

3. insect and animal bites …. Rabies, West Nile both can lead to encephalitis

4. blood contact …. HIV, Hepatitis B ( 400x more infectious than HIV) , Hepatitis C

5. Provirus have the virus but its a state that persists over longer periods of time as inactive

Viral diseases can not be treated with antibiotics because the enzymes they destroy are not present

Also some antibiotics work on the cell wall of the organism.

Others block protein synthesis by binding ribosomes.

Viruses are merely nucleic acid (RNA and or DNA) and protein. Hence antibiotics are ineffective on viruses.

Vaccines stimulate the immune system to fight

The term vaccine derives from Edward Jenner's 1796

use of the term cow pox (from the Latin vaccīn-us,

from vacca cow), which, when administered to

humans, provided them protection against smallpox.

Stages a virus may be in

1. Virulent – cause the disease

2. Temperate – virus doesn’t cause a disease immediately

A virulent virus is one which is highly capable of causing severe disease while a temperate virus is one which would cause mild symptoms if any at all.

Methods of study

1. Tissue culture – grow cells, viruses

2. Serology – study of biological fluids

Such as blood

3. Electrophoresis – separates fragments

of large molecules ( like DNA - charge)

based on electrical charge

Types of Viruses

1. DNA virus Poxvirus – small pox

Herpes virus – cold sore

mono

chicken pox

2. RNA virus Rhabdovirus – rabies

flu , measles, cold

3. Retrovirus makes DNA from RNA using an enzyme called reverse transcriptase, makes a new virus

HIV/ Leukemia

Lytic Cycle

Means lyse or break

Form of replication

Phage is a virus that

infects bacteria

Step 1 virus attaches to the cell

Step 2 releases enzymes, weakens cell

Step 3 injects DNA or RNA which takes over the cells DNA

Step 4 uses the cells DNA to assemble new phages using protein synthesis

Step 5 enzyme breaks cell wall, virus burst out

The lysogenic cycle

• integration of the bacteriophage DNA into the host bacterium's genome.

• The virus is called a prophage which can be transmitted to daughter cells at each subsequent cell division

• Inactive, temperate till condition releases it into lytic cycle

Other infectious agent

• Viroid has RNA no capsid ex plant pathogen

transmitted by pollen and seed and by several insects or a kitchen knife

Potato spindle tuber viroid

• Prion has capsid no nucleic acid ex scrapie, kuru

mad cow