what are bacteria? how are they classified? are they good or bad? warm up

What are bacteria?What are bacteria?

How are they How are they classified?classified?

Are they good or Are they good or bad? bad?

Warm UpWarm Up

What are the 6 What are the 6 Kingdoms?Kingdoms?

ArchaebacteriaArchaebacteriaEubacteriaEubacteriaProtistsProtistsFungiFungiPlantsPlantsAnimalsAnimals

Monera

Kingdom MoneraMost numerous organism on EarthMost AncientMicroscopic ProkaryotesEvolution has yielded many species

adapted to survive where no other organisms can.

Grouped based on: Structure, physiology, molecular

Composition, reaction to specific types of stain.

Eubacteria= Germs/bacteriaArchaebacteria

ArchaebacteriaArchaebacteria Live in Live in

extreme extreme locationslocations::– OxygenOxygen-free -free

environmentsenvironments– Concentrated Concentrated

salt-watersalt-water– Hot, acidic Hot, acidic

waterwater

Methanogensmake methane (natural gas

Halophiles can turn extremely salty environments pink

Thermophiles can grow In hot springs and boilingwater

Methanogens

EubacteriaEubacteria Heterotrophs –found Heterotrophs –found everywhere and lives everywhere and lives off living/dead off living/dead organisms organisms

Photosynthetic Photosynthetic autotrophs – makes autotrophs – makes their own foodtheir own food

Chemosynthetic Chemosynthetic autotrophsautotrophs

The first organisms on The first organisms on Earth to do modern Earth to do modern photosynthesis photosynthesis

What are bacteria?What are bacteria?Single celled organismsSingle celled organisms

Very smallVery small

Need a microscope to Need a microscope to seesee

Can be found on most Can be found on most materials and surfacesmaterials and surfaces Billions on and in your Billions on and in your body right nowbody right now

E. Coli O157:H7 can make you very sick.

Streptococcus can cause strep throat.

This E. coli helps you digest food.

This is a pore in human skin and the yellow spheres are bacteria

99

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

Bacteria

1010

Clean skin has about 20 million bacteria per

square inch

What do they look like?What do they look like?

Three basic shapesThree basic shapes– Rod shaped called Rod shaped called

bacilli (buh-sill-eye)bacilli (buh-sill-eye)– Round shaped called Round shaped called

cocci (cox-eye)cocci (cox-eye)– Spiral shapedSpiral shaped

Some exist as Some exist as single cells, others single cells, others

cluster togethercluster together

Bacilli

Spiral

Cocci

Cluster of cocciUSDA NIFSI Food Safety in the Classroom©University of Tennessee, Knoxville 2006

Bacteria are ALIVE!Bacteria are ALIVE!

What does it What does it mean to be alive?mean to be alive?

– They reproduce They reproduce (make more of (make more of themselves)themselves)

– They need to eatThey need to eat

USDA NIFSI Food Safety in the Classroom©University of Tennessee, Knoxville 2006

How do bacteria reproduce?How do bacteria reproduce?

Grow in number not in sizeGrow in number not in size– Humans grow in size from child to adultHumans grow in size from child to adult

Make copies of themselves by Make copies of themselves by dividing in halfdividing in half– Human parents create a childHuman parents create a child


1515

•Binary Fission- the process of one organism dividing into two organisms

•Fission is a type of asexual reproduction

Reproduction of BacteriaReproduction of Bacteria

How?...The one main (circular) chromosome makes a copy of itselfThen it divides into two

•Asexual reproduction- reproduction of a living thing from only one parent

Bacteria dividing Completed

A closer look at how Bacteria A closer look at how Bacteria reproducereproduce

Binary Fission – Binary Fission – reproduction in reproduction in which a bacteria which a bacteria cell divides into cell divides into two cells that are two cells that are the same as the the same as the originaloriginal. . They They can reproduce in can reproduce in 15 minutes if 15 minutes if resources are resources are available.available.

How do bacteria eat?How do bacteria eat? Some make their own food from Some make their own food from

sunlight—like plantssunlight—like plants

Some are scavengersSome are scavengers– Share the environment around themShare the environment around them

Example: The bacteria in your stomach Example: The bacteria in your stomach are now eating what you ate for breakfastare now eating what you ate for breakfast

Some are warriors (pathogens)Some are warriors (pathogens)– They attack other living things They attack other living things

Example: The bacteria on your face can Example: The bacteria on your face can attack skin causing infection and acneattack skin causing infection and acne

Photosynthetic bacteria

Harmless bacteria on the stomach lining

E. Coli O157:H7 is a pathogenUSDA NIFSI Food Safety in the Classroom©

University of Tennessee, Knoxville 2006

Bacteria are of Bacteria are of immense immense importance importance because of their because of their rapid growth, rapid growth, reproduction, and reproduction, and mutation rates, as mutation rates, as well as, their ability well as, their ability to exist under to exist under adverse conditions. adverse conditions.

The oldest fossils The oldest fossils known, nearly 3.5 known, nearly 3.5 billion years old, are billion years old, are fossils of bacteria-fossils of bacteria-like organisms.like organisms.

Bacteria are often Bacteria are often maligned as the maligned as the causes of human causes of human and animal disease. and animal disease. However, certain However, certain bacteria, the bacteria, the actinomycetes, actinomycetes, produce antibiotics produce antibiotics such as such as streptomycin and streptomycin and nocardicin. nocardicin.

What is a pathogen?What is a pathogen?

Bacteria that make you sickBacteria that make you sick

– Why do they make you sick?Why do they make you sick?

To get food they need to survive and To get food they need to survive and reproducereproduce

– How do they make you sick?How do they make you sick?

They produce poisons (toxins) that result in They produce poisons (toxins) that result in fever, headache, vomiting, and diarrhea and fever, headache, vomiting, and diarrhea and destroy body tissuedestroy body tissue


Where do you get a Where do you get a pathogen?pathogen?

Contact with people who are sickContact with people who are sick

– Direct or indirectDirect or indirect

Food, Water, or other Surfaces Food, Water, or other Surfaces that are contaminatedthat are contaminated

Indirect contact

Direct contact

Foods that could be

contaminated


A Closer Look – Where do you A Closer Look – Where do you get a pathogenget a pathogen

Indirect Contact

Direct Contact

Foods and water may be contaminated


Are all bacteria pathogens?Are all bacteria pathogens? No, most are harmlessNo, most are harmless

Some are even helpfulSome are even helpful– Examples of helpful bacteria:Examples of helpful bacteria:

LactobacillusLactobacillus: makes cheese, : makes cheese, yogurt, & buttermilk and produces yogurt, & buttermilk and produces vitamins in your intestinevitamins in your intestine

LeuconostocLeuconostoc: makes pickles & : makes pickles & sauerkrautsauerkraut

PediococcusPediococcus: makes pepperoni, : makes pepperoni, salami, & summer sausagesalami, & summer sausage


A Closer Look – Helpful A Closer Look – Helpful BacteriaBacteria

Pediococcus - used in production of fermented meats

Leuconostoc cremoris – used in the production of buttermilk and sour cream

Lactobacillus casei – found in human intestines and mouth to improve digestion

Lactobacillus bulgaricus – used in the production of yogurt

www.bioweb.usu.edu


Other Bacteria live Other Bacteria live symbiotically in the symbiotically in the guts of animals or guts of animals or elsewhere in their elsewhere in their bodies.bodies.

E.coli on small intestines

For example, bacteria in your gut produce vitamin K which is essential to blood clot formation.

Still other Bacteria Still other Bacteria live on the roots of live on the roots of certain plants, certain plants, converting nitrogen converting nitrogen into a usable form.into a usable form.

What are some common What are some common pathogens?pathogens?

Pathogenic Pathogenic E. coliE. coli (like O157:H7)(like O157:H7)– Found in ground beef, Found in ground beef,

contaminated fruits and contaminated fruits and vegetablesvegetables

SalmonellaSalmonella– Found in raw meats, poultry, eggs, Found in raw meats, poultry, eggs,

sprouts, fruit and vegetablessprouts, fruit and vegetables

ListeriaListeria– Found in deli foods, lunch meats, Found in deli foods, lunch meats,

smoked fish and vegetablessmoked fish and vegetables

E. coli O157:H7

Salmonella

ListeriaUSDA NIFSI Food Safety in the Classroom©

University of Tennessee, Knoxville 2006

Examples of PathogensExamples of PathogensSalmonella

Staphylococcus aureus

Campylobacter jejuni

E. coli O157:H7

What shape are these bacteria?

Cocci, bacilli, or spiral?


Kingdom ProtistsKingdom Protists

Protista can be PathogensProtista can be Pathogens

The Protista The Protista kingdom includes kingdom includes Algae, and Algae, and Protozoans. They Protozoans. They may have features may have features like those of plants, like those of plants, animals, and fungi. animals, and fungi. They may be single They may be single celled or celled or multicellular.multicellular.

Protist can reproduce Protist can reproduce sexually or asexuallysexually or asexually

MeiosisMeiosis Budding and FissionBudding and Fission

Common Protista PathogensCommon Protista Pathogens

• Sporozoan – lives in blood Sporozoan – lives in blood and may cause malariaand may cause malaria. .

Trypanosome – lives in Trypanosome – lives in blood and may cause blood and may cause sleeping sickness.sleeping sickness.

Entamoeba histolytica Entamoeba histolytica – lives in the intestines – lives in the intestines andd can cause andd can cause severe diarrhea. severe diarrhea.

How do they move ?How do they move ?

Groups are based on movement . This includes movement byGroups are based on movement . This includes movement by

flagella, cilia, pseudopods . flagella, cilia, pseudopods . false feet’

Whip like structure

Hair like structure

Streaming cytoplasm

Viruses Viruses

What are Viruses?What are Viruses? Viruses and smaller Viruses and smaller

than bacteria and than bacteria and much smaller than much smaller than eukaryotes. eukaryotes.

They consist of a They consist of a shell made of protein shell made of protein and lipid which and lipid which protect the genetic protect the genetic material inside.material inside.

They are not alive They are not alive and none are helpful.and none are helpful.

How do Viruses reproduce?How do Viruses reproduce? Viruses cannot reproduce or express their genes Viruses cannot reproduce or express their genes

without the help of a living cell. without the help of a living cell.

Once a virus has "infected" a cell, it will “control" Once a virus has "infected" a cell, it will “control" the cell's ribosomes, enzymes and much of the the cell's ribosomes, enzymes and much of the cellular machinery to reproduce.cellular machinery to reproduce.

Viral reproduction produces many, many progeny, Viral reproduction produces many, many progeny, that when complete, leave the host cell to infect that when complete, leave the host cell to infect other cells in the organism.other cells in the organism.

How do Viruses reproduce?How do Viruses reproduce?

Diseases cased by VirusesDiseases cased by Viruses

Avian or Bird FluAvian or Bird Flu Swine FluSwine Flu Meningitis Meningitis MononucleosisMononucleosis WartsWarts HepatitisHepatitis BronchiolitisBronchiolitis Colorado Tick Colorado Tick

FeverFever EncephalitisEncephalitis

Common Cold Common Cold HIV-AIDSHIV-AIDS InfluenzaInfluenza Measles Measles

(Rubella)(Rubella) MumpsMumps PolioPolio RabiesRabies SmallpoxSmallpox Hepatitis Hepatitis Herpes Herpes

FungiFungi

What is a Fungi?What is a Fungi? Fungi are Eukaryotic Fungi are Eukaryotic

heterotrophs and are heterotrophs and are unicellular and unicellular and multicellularmulticellular

Some live as saprophytes Some live as saprophytes (live on rotting organic (live on rotting organic matter) matter)

They perform a crucial role They perform a crucial role in nature by decomposing in nature by decomposing dead organisms dead organisms

Some live in a mutually Some live in a mutually beneficial symbiotic beneficial symbiotic relationship relationship

How do Fungi ReproduceHow do Fungi Reproduce

AsexuallyAsexuallyThey produce sporesThey produce spores

Sexually Sexually Budding – Buds that Budding – Buds that break of from the break of from the parent and produce an parent and produce an identical copyidentical copyMeiosis – sharing Meiosis – sharing DNA wit similar fungiDNA wit similar fungi

Examples of FungiExamples of Fungi

yeasts molds

mildews Yeast: Candida albicans

Mushrooms

How can I avoid pathogens?How can I avoid pathogens?

Wash your hands often so you Wash your hands often so you won’t transfer bacteria to your won’t transfer bacteria to your mouth or foodmouth or food

– Warm water with soap for 20 Warm water with soap for 20 seconds, rub hard between fingers seconds, rub hard between fingers and nailsand nails


Cook food thoroughly to Cook food thoroughly to kill any pathogens that kill any pathogens that may be in your foodmay be in your food

Store food properly to Store food properly to limit pathogen growthlimit pathogen growth

– Cold temperatures (40Cold temperatures (40F)F)

How can I avoid pathogens?How can I avoid pathogens?


4545

Controlling BacteriaAntiseptic vs. Disinfectants

Antiseptic- chemicals that kill bacteria on living things

•means – “against infection”

Examples: iodine, hydrogen peroxide, alcohol, soap, mouthwash

Disinfectants- stronger chemicals that destroy bacteria on objects or nonliving things

Bacteria are prokaryotic and Bacteria are prokaryotic and unicellular.unicellular.

Bacteria have cell walls.Bacteria have cell walls. Bacteria have circular DNA called Bacteria have circular DNA called

plasmidsplasmids Bacteria can be anaerobes or aerobes.Bacteria can be anaerobes or aerobes. Bacteria are heterotrophs or Bacteria are heterotrophs or

autotrophs.autotrophs. Bacteria are awesome!Bacteria are awesome!

ReviewReview

ReviewReviewBacteria, Fungi, and Protista Bacteria, Fungi, and Protista

are living organismsare living organisms

Most are harmlessMost are harmless

A few are pathogens that A few are pathogens that make you sickmake you sick

You can reduce the risk of You can reduce the risk of getting sick by washing your getting sick by washing your hands and handling food hands and handling food properly.properly.


Review Shapes of BacteriaReview Shapes of Bacteria

Stained Bacteria Cells Stained Bacteria Cells

Stained Protozoa cellsStained Protozoa cells

Stained Fungi cellsStained Fungi cells

Bacteria can reproduce Bacteria can reproduce sexuallysexually by by conjugationconjugation or or asexuallyasexually by by binary fissionbinary fission..

EndosporeEndospore

Bacteria can Bacteria can survive survive unfavorable unfavorable conditions by conditions by producing an producing an endosporeendospore..

Penicillin kills bacteria by making holes in their cell walls. Unfortunately, many bacteria have developed resistance to this antibiotic.

Penicillin, an antibiotic, comes from molds of the genus Penicillium Notice the area of inhibition around the Penicillium.

The The Gram stainGram stain, which divides most , which divides most clinically significant bacteria into two clinically significant bacteria into two main groups, is the first step in main groups, is the first step in bacterial identification. bacterial identification.

Bacteria stained Bacteria stained purple are Gram + purple are Gram + - - their cell walls have thick petidoglycan their cell walls have thick petidoglycan and teichoic acid. and teichoic acid.

Bacteria stained Bacteria stained pink are Gram – pink are Gram – their their cell walls have have thin peptidoglycan cell walls have have thin peptidoglycan and lipopolysaccharides with and lipopolysaccharides with nono teichoic acid.teichoic acid.

In Gram-positive bacteria, the purple crystal violet stain is trapped by the layer of peptidoglycan which forms the outer layer of the cell. In Gram-negative bacteria, the outer membrane of lipopolysaccharides prevents the stain from reaching the peptidoglycan layer. The outer membrane is then permeabilized by acetone treatment, and the pink safranin counterstain is trapped by the peptidoglycan layer.

The Gram stain has four steps:The Gram stain has four steps: 1. 1. crystal violet,crystal violet, the the primary stainprimary stain: :

followed byfollowed by

2. 2. iodineiodine, which acts as a , which acts as a mordantmordant by forming a crystal violet-iodine by forming a crystal violet-iodine complex, thencomplex, then

3. 3. alcoholalcohol, which , which decolorizesdecolorizes, , followed byfollowed by

4. 4. safraninsafranin, the , the counterstaincounterstain..

Is this gram stain positive or negative? Is this gram stain positive or negative? Identify the bacteria.Identify the bacteria.

Gram staining tests the bacterial cell wall's Gram staining tests the bacterial cell wall's ability to retain ability to retain crystal violetcrystal violet dye during dye during solvent treatment. solvent treatment.

Safranin is added as a mordant to form the Safranin is added as a mordant to form the crystal violet/safranincrystal violet/safranin complex in order to complex in order to render the dye impossible to remove. render the dye impossible to remove.

Ethyl-alcohol solvent acts as a decolorizer Ethyl-alcohol solvent acts as a decolorizer and dissolves the lipid layer from gram-and dissolves the lipid layer from gram-negative cells. This enhances leaching of negative cells. This enhances leaching of the primary stain from the cells into the the primary stain from the cells into the surrounding solvent.surrounding solvent.

Ethyl-alcohol will dehydrate the thicker Ethyl-alcohol will dehydrate the thicker gram-positive cell walls, closing the pores gram-positive cell walls, closing the pores as the cell wall shrinks. as the cell wall shrinks.

For this reason, the diffusion of the crystal For this reason, the diffusion of the crystal violet-safranin staining is inhibited, so the violet-safranin staining is inhibited, so the bacteria remain stained. bacteria remain stained.

what are bacteria? how are they classified? are they good or bad? warm up

Documents

fossils of bacteria

bacteria cell divides

pathogenusda nifsi food

childusda nifsi food

eatusda nifsi food safety

single cells

human skin

clean skin