BacteriaBacteria and and

Their EnvironmentTheir Environment

ExamplesExamples

1.1. Organisms that survive at Organisms that survive at Low Low Temperatures-Temperatures- psychrophilepsychrophile (Serratia marcescends and the North (Serratia marcescends and the North Pole)Pole)

2.2. Organisms that survive at Organisms that survive at High High Temperatures- thermophileTemperatures- thermophile (Thermus aquaticus and hot tubs)(Thermus aquaticus and hot tubs)

TermsTerms

1.1. Thermophiles – Like it hotThermophiles – Like it hot

2.2. Psychrophile – Like it coldPsychrophile – Like it cold

3.3. Mesophile – BetweenMesophile – Between

Can we use temperature to injure bacteria?Can we use temperature to injure bacteria? Heat- Denatures proteins (cooks them)Heat- Denatures proteins (cooks them)

-fried egg example-fried egg example Cold- Freezes H2O into crystals (does not Cold- Freezes H2O into crystals (does not

kill – only “stalls”)kill – only “stalls”)

Effect of salt solutions on Effect of salt solutions on microbes:microbes:

0% salt0% salt – Hypotonic (Hemolysis) – Hypotonic (Hemolysis)

1% salt1% salt – Isotonic (.9%) – Isotonic (.9%)10% salt10% salt – Hypertonic (more dissolved – Hypertonic (more dissolved

salt)salt)

15% salt15% salt – Hypertonic (Plasmolysis) – Hypertonic (Plasmolysis)

Effect of Electromagnetic Effect of Electromagnetic Spectrum EnergySpectrum Energy

1.1. Visible light-Visible light- No harm No harm2.2. Infra red-Infra red- No harm No harm3.3. Ultra VioletUltra Violet – Dangerous to bacteria – Dangerous to bacteria

(damages DNA)(damages DNA)4.4. X-raysX-rays- Denatures proteins and breaks DNA- Denatures proteins and breaks DNA-Micrococcuis radiodurans can tolerate more -Micrococcuis radiodurans can tolerate more

radioactivity than any other cellradioactivity than any other cell

How do companies sterilize most products How do companies sterilize most products produced? I.e. sterile gauze?produced? I.e. sterile gauze?

Effects of Agents on Effects of Agents on BacteriaBacteria1.1. Antiseptic-Antiseptic- inhibit growth ( inhibit growth (weakensweakens

bacteria agents) Neosporin, Iodine, bacteria agents) Neosporin, Iodine, H2O2, used on tissuesH2O2, used on tissues

2.2. Disinfectant-Disinfectant- cleaning agent ( cleaning agent (killskills bacteria) Lysol, AJAX, Pine solbacteria) Lysol, AJAX, Pine sol

3.3. Chemical Examples:Chemical Examples: Antibiotics- Block essential reactionsAntibiotics- Block essential reactions Sulfanilamide- block DNA formationSulfanilamide- block DNA formation Detergents- Kills germs with soap affecting Detergents- Kills germs with soap affecting

cellcell Halogens- Burn and oxidize cellsHalogens- Burn and oxidize cells Alcohol- DehydratesAlcohol- Dehydrates Heavy Metal (silver/gold)- olygodynamic Heavy Metal (silver/gold)- olygodynamic

effecteffect