Biology Chapter 20 Bacteria Extremophiles Hot springs Food

Biology Chapter 20 Bacteria

Extremophiles: Hot springs Food: Acidolpholus

Bacteria as symbionts Illness: Pneumonia (parasitic) Digestion: Mutualism

Decomposers: Free nutrients Final energy acceptors Unique characteristics cont… Symbiosis: bioluminescence

• Bacteria are: Bacteria are • A. microscopic Prokaryotic cells • B. prokaryotes • 1. No membrane bound nucleus or organelles • 2. DNA is a single loop or plasmids • 3. cell wall of peptoglycan (sugar)

BACTERIA cont 1. Are Unicellular: live as colonies or filiments 2. Are prokaryotic: no membrane bound organelles, no membrane bound nucleus 3. Posses a Capsule: 4. protects the bacteria cell from digestion 5. Posess Cell walls long chains of polysacharrides, strong & rigid; resists osmotic pressure 5. Posses Pili: hairlike structures that enable bacteria to stick to surfaces & each other

Classification • Bacteria are placed into 2 different kingdoms • Archaebacteria (ancient bacteria) typically live in extreme environments • Eubacteria (true bacteria) common bacteria- E. Coli, Salmonella

“Archae” “Ancient bacteria” • Bacteria that live in extreme environs Thermophiles- bacteria that live in hot environs Halophiles- bacteria that live in salty environs Acidophiles- bacteria that live in acidic environs Some may live in Oxygen free environs and produce methane gas and are called “methanogens” • 0. 5 -1. 0 microns

Kingdom Eubacteria the ”true” bacteria • Account for most bacteria today • Found in every niche in the ecosystem, soil, water, on & in animals. Are classified by 1. gram stain test 2. Shape 3. motility

If a bacterium is gram positive, its cell membrane is surrounded by a thick cell wall made of peptidoglycan. G+ bacteria react differently to drugs, produce different toxins, react differently to disinfectants. G+ bacteria absorb crystal violet stain and turn “blue” Gram Positive bacteria

A gram negative bacteria has 2 cell membranes (lipid bilayer) surrounding a thin cell wall. G- bacteria will absorb “Safrinin” a nonpolar stain, and turn red Gram Negative Bacteria

Bacteria are classified and organized by: 1. How they obtain energy (nutrition) aututroph/heterotroph

Nutrition Requirements Heterotrophs: obtain energy from digesting organic matter (decomposers) or living matter (parasites) Autotrophs: obtain energy from sunlight via photosynthesis and via minerals Photoautotrophs: only use sunlight as energy source. (blue-green algae) Chemoautotrophs: convert inorganic compounds into a usable form. (sea floor vents) and hot springs

Heterotrophs Bacteria that obtain their energy through consuming other things. 4 lifestyles exhibited; Free living decomposers aka “saprophytes” parasitic, mutualism commensal

Saprophytes “The Decomposers” • Heterotrophic bacteria that feed on dead or decaying material in all ecosystems.

Commensals • “Commensals” bacteria cover your skin forming a “microbial lawn” They help to keep other bacteria that may be harmful from occupying that niche

Parasitic bacteria A relationship in which the bacteria benefits, and the host is harmed. We generally consider these “disease” causing bacteria Lyme diseae spirochete

Autotrophs Cyanobacteria aka “Blue-green algae” • Bacteria that use sunlight as an energy source. • Includes Marine algae freshwater algae • Major source of organics that became “oil”

Chemoautotrophs • Chemoautotrophs use inorganic energy sources, such as Hydrogen sulfide, elemental Sulfur, ferrous Iron, molecular Hydrogen, and ammonia • They drive the food chain at hydrothermal vents on the seafloor

2. Classification by: Oxygen Requirements • Obligate aerobes: can only survive in the presence of Oxygen • Obligate anaerobes; can only survive in an environment without Oxygen • Faculatative anaerobes/ aerobes can survive and grow with or without Oxygen.

Obligate anaerobes • Cannot survive in the presence of Oxygen. • Clostridium tetani and botulism(photo), a bacteria that causes food poisoning are examples

Facultative anaerobes • Bacteria that can live with or without Oxygen. • Escheria Coli, lives in the human digestive tract as a commensal symbiont is a facultative anaerobe

Obligate aerobes • Must live in the presence of Oxygen. • Tuberculosis is an example of an obligate aerobe. It lives in the lungs and causes TB

3. Classification by: Movement flagella: long protein based “hairs” 1 or several that allow “tumbling” usually through a liquid substrate. • 1 hair- monotrichous • Single flagellum at both ends- amphitrichous • Tuft of flagella at one endlophotrichous

Movement #2 Glide by producing a layer of slime, then using peristalsis to move through it.

Movement #3 Spiraling • Spirilis shaped bacteria move in “corkscrew” fashion.

4. Classification by shape

EUBACTERIA • SHAPES • GROUPING • • • Strepto-chains • Staphlo-clusters (grapes) • Diplo-two Cocci-sphere/circle Bacilli-rod Spirilla-S-shaped Vibrio-V-shaped • Ie. Streptococcus chains of spheres

Coccus (spheres)

Streptococcus

Staphylococcus

Bacillus (rods)

Streptobacillus “Chains of rods”

Vibrio • “bent rods” • Around 80 species • Mostly marine and cause foodborne illness • (seafood)

Binary Fission (asexual) the single DNA molecule replicates and the original cell is divided into two identical cells through normal cell division. Under favorable conditions—this can repeat every 20 minutes

Reproduction by “Transformation” • TRANSFORMATION one bacterial cell “engulfs” DNA from its environment(another bacterial cell)

Reproduction by conjugation • CONJUGATION pili (hair like projections) from one bacteria attaches to another bacteria and forms a conjugation bridge. • DNA is exchanged

• CONJUGATION (continued) a plasmid contains some DNA and this replicates in the host bacteria and the new plasmid transfers through the bridge

Reproduction by “TRANSDUCTION” In this process, bacteria transfer foreign DNA to each other via a virus. When bactiophages infect a bacterium, the viral DNA can be included in the bacterial genome

Classification by Gram Stain

Are All Bacteria Bad? • Many are useful and important • Produce cheese, sour cream, yogurt, sauerkraut • Break down organic compounds (decomposers) • Many antibiotics derived from bacteria

How to combat disease causing bacteria?

ANTIBIOTICS !! • Antibiotics are often derived from bacteria • Antibiotics interfere with bacterias cellular function – Hit cell wall – Interrupt protein synthesis – Inhibit enzyme synthesis – Disrupt DNA metabolism – Staphyllococcus Cell wall disintegration by the antibiotic – ceftazidine

Antibiotic Information • Antibiotic may be narrow spectrum -target specific properties of the bacterium • Antibiotic may be broad spectrum -target all areas, leads to resistance • Many antibiotics target the cell wall so are useless against Gram neg bacteria (lipid layer on outside)

Antibiotic Resistance • When antibiotic introduced, most bacteria die • Those that live have resistance to the drug, usually due to a mutation • Those bacteria that live reproduce and grow new population • Now entire population resistant to the drug

Bacterial Diseases • SALMONELLA • Nausea, vomiting, abdominal cramps, diarrhea, fever, headache

Bacterial Diseases • TYPHUS • Fever, delirium, rash • If left untreated, may die in 3 weeks

Bacterial Diseases • LEPROSY • Severe disfigurement especially of feet, hands, and face

Bacterial Diseases • DIPTHERIA • Cause a membrane to grow around the inside of throat, leading to difficulty in swallowing, breathlessness, and suffocation • Toxin may spread through entire body

Bacterial Diseases • BACTERIAL PNEUMONIA • Infection of lungs. Air sacs in lungs fill with puss and other liquid

Bacterial Diseases • TETANUS • Bacteria enter through wound, cause muscle rigidity and painful spasms