Bacteria

Bacteria are very small

This is a pore in human skin and the yellow spheres are bacteria Scanning electron image of bacteria on skin.

Bacteria compared to a white blood cell that is going to eat it

Clean skin has about 20 million bacteria per square inch

Classification Most numerous on Earth Most Ancient Microscopic Prokaryotes Evolution has yielded many species adapted to survive where no other organisms can. Grouped based on: Structure, physiology, molec. Composition reaction to specific types of stain. Eubacteria= Germs/bacteria Archaebacteria

Kingdom Archaebacteria First discovered in extreme environments Methanogens: Harvest energy by converting H2 and CO2 into methane gas Anaerobic, live in intestinal tracts Extreme halophiles: Salt loving, live in Great Salt Lake, and Dead sea. Thermoacidophiles: Live in acid environments and high temps. Hot Springs, volcanic vents

The red color of this snow is due to a blue-green bacteria

Kingdom Eubacteria Bacilli – rod-shaped Spirilla – spiral-shaped Can have one of three basic shapes Bacilli – rod-shaped Spirilla – spiral-shaped Cocci – sphere-shaped Staphylococci – grape-like clusters Streptococci – in chains

BACTERIA PICS

Coccus bacteria are sphere or ball shaped

Spirillium bacteria have a corkscrew shape

Staphylo - bacteria occur in clumps, such as this staphylococcus bacteria that causes common infections of cuts

Strepto- bacteria occur in chains of bacteria, such as this streptococcus bacteria that causes some types of sore throats

Spirillium bacteria

The red and yellow dots are bacteria The tip of a needle The red and yellow dots are bacteria

STRUCTURE OF BACTERIA Structure Function Cell Wall Protects and gives shape Outer Membrane Protects against antibodies (Gram Neg. Only) Cell Membrane Regulates movement of materials, contains enzymes important to cellular respiration Cytoplasm Contains DNA, ribosomes, essential compounds Chromo-some Carries genetic information Plasmid Contains some genes obtained through recomb. Capsule & Slime Layer Protects the cell and assist in attaching cell to other surfaces Endospore Protects cell agains harsh enviornments Pilus Assists the cell in attaching to other surfaces Flagellum Moves the cell

No Nucleus-DNA in Cytoplasm

Nutrition and Growth Temperature requirements Heterotrophic or Autotrophic Some are Photoautotrophs – Use sunlight for Energy Some are Chemoautotrophs. Many are Obligate Anaerobes. Oxygen = Death Ex. Clostridium tetani – Tetanus Some are Faculatative Anaerobes With or without Oxygen Ex. Escherichia Coli Some are Obligate Aerobes Ex.) Mycobacterium tuberculosis Temperature requirements Some are Thermophilic, Some prefer acidic envmt.

Bacteria and Disease Disease Pathogen Areas affected Mode of transmission Botulism Clostridium botulinum Nerves Improperly preserved food Cholera Vibrio cholerae Intestine Contaminated water Dental Caries Streptococcus mutans, sanguis, salivarius Teeth Environment to mouth Gonorrhea Neisseria gonorrhoeae Urethra, fallopian Sexual contact Lyme disease Berrelia burgdorferi Skin, joints Tick bite Rocky Mountain SF Rickettsia recketsii Blood, skin Salmonella Contaminated food, water Strep throat Streptococcus pyogenes URT, blood, skin Sneezes, coughs, etc. Tetanus Costridium tetani Contaminated wounds Tuberculosis Mycobacterium tuberculosis Lung, bones coughs

Helicobacter pylori is the pathogenic bacteria that can causes ulcers

Leprosy is a bacterial infection that decreases blood flow to the extremities resulting in the deterioration of toes, ears, the nose and the fingers.

BOTULISM

CHOLERA

DENTAL CARIES

ROCKY MOUNTAIN SF

LYME DISEASE

SALMONELLA

STREP THROAT

TUBERCULOSIS

Common Antibiotics Antibiotic Mechanism Target bacteria Penicillin Inhibits cell wall synthesis Gram Positive Ampicillin Broad spectrum Bacitracin Gram Positive – Skin Ointment Cephalosporin Tetracycline Inhibits Protein Synthesis Streptomycin Gram Neg. tuberculosis Sulfa drug Inhibits cell metabolism Bacterial meningitis, UTI Rifampin Inhibits RNA synthesis Gram Pos., some Neg. Quinolines Inhibits DNA Synthesis UTI

How Science is Helping Bacteria Because antibiotics have been overused, many diseases that were once easy to treat are becoming more difficult to treat. Some Bacteria are Useful Ex.) Producing and Processing food Breaking down dead organic material Make unripened cheese like ricotta and cottage by breaking down the protein in milk.

Non-living but depends on the living! VIRUSES Non-living but depends on the living!

STRUCTURE Nonliving Composed of Nucleic acid and protein Cause many diseases Virology – Study of Viruses Comparison of Viruses and Cells below Char. Of Life Virus Cell Growth No Yes Homeostasis Metabolism Mutation Nucleic acid DNA or RNA DNA Reproduction Only within host cell Independently by cell division Structure Nucleic acid core, protein covering, some have envelope Cytoplasm, cell membrane, etc..

Here is a non-enveloped bacteria virus inserting it’s DNA into a bacterial cell.

Some virus are pushed out by the cell, taking some of the cell membrane with them.

Characteristics of Viruses 2 essential features 1. Nucleic Acid May be DNA or RNA Helical, closed loop, or long strand 2. Protein Coat – called CAPSID Some have ENVELOPE Ex. Influenza, chickepox, herpes simplex, HIV VIRAL SHAPE Icosahedron – 20 triangular faces Ex.) herpes, chickenpox, polio Helix – Coiled spring EX.)Rabies, measles, tobacco mosaic

All viruses have two main parts: DNA or RNA – genetic info Capsid – a protein encasement

Grouping Viruses Grouped according to: Presence of Capsid and envelope – shape RNA or DNA, single or double stranded – struct. Viral Group Nucleic Acid Shape and Structure Example Papovaviruses DNA Icosahedral, non-env. Warts, cancer Adenoviruses Resp. & intestinal infections Herpesviruses Icosahedral, enveloped Herpes simplex, chicken pox, mono, shingles Poxviruses Complex brick, enveloped Small pox, cow pox Picornaviruses RNA Polio, hepatitis, cancer Myxoviruses Helical, enveloped Influenza A, B, C Rhabdoviruses Rabies Retroviruses AIDS, cancer

Grouping Viruses Viroids- The smallest known particle that can replicate. Disrupt plant cell metabolism Can destroy entire crops Prions – Abnormal forms of proteins that clump together inside cells. Clumping eventually kills the cell Examples Scrapie – in sheep Mad Cow Disease

PRIONS – man-made problem?

Viral Replication Can replicate only by invading host cell and using its enzyme and organelles. Bacteriophage – viruses that infect bacteria Used to study viruses Lytic Cycle Viral genome is released into the host cell Replication follows immediately Cellular components used to make new viruses Viral enzyme kills cell.

Replication cont’ Lysogenic Cycle Nucleic acid of virus becomes part of the host cell’s chromosome Nucleic acid remains in the cell in this form for many generations HIV follows this pattern HIV infects WBC and remains as proviruses As immune system fails, opportunistic infections occur = AIDS

Here is a classic picture of HIV viral progeny being released from the surface of a T- cell. Notice the membrane coating they receive.

Viruses and Human Disease Control and Prevention of spread. Vaccination & Antiviral drugs Ex.) chickenpox vaccine, AZT, Acyclovir, protease inhibitors. Emerging Viruses – exist in isolated habitats Do not usually infect humans unless environmental conditions favor contact. Several viruses are now linked to cancers such as leukemia, liver cancer, Burkitt’s lymphoma, cervical cancer.

PAPOVAVIRUSES BACK

POXVIRUSES BACK

PICORNAVIRUSES Polio BACK

After polio infections, the killer T-cell have destroyed the motor neurons that are producing the virus. The result is a loss of muscle control including the diaphragm. The iron lung changes the pressure to pump air in and out of the lungs.

MYXOVIRUSES BACK

RHABDOVIRUSES BACK

RETROVIRUSES AIDS BACK

Time to take ownership What you need to know! Bacteria and virus structures Types of bacteria Types of viruses How bacteria and viruses cause infection What can be done to treat, cure or prevent viral and bacterial infections.