How many arrows do you see
Download
1 / 86

How many arrows do you see in the following shape - PowerPoint PPT Presentation


  • 339 Views
  • Uploaded on

How many arrows do you see in the following shape?. Microbial Growth. Microbiology 2314. Bacterial Growth. Bacterial Growth is Bacterial Reproduction The Numbers of Bacteria are Increasing We see: 1. Observable Increases in Colonies Growing on Solid Media

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'How many arrows do you see in the following shape ' - Jimmy


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Slide1 l.jpg

How many arrows do you see

in the following shape?


Microbial growth l.jpg

Microbial Growth

Microbiology 2314


Bacterial growth l.jpg
Bacterial Growth

  • Bacterial Growth is Bacterial Reproduction

  • The Numbers of Bacteria are Increasing

  • We see:

    1. Observable Increases in Colonies

    Growing on Solid Media

    2. Turbidity, Sediment, Scum or a

    Change in Color in Broth Cultures




Slide8 l.jpg

Generation Time

The Time Required for a Cell to Divide




Generation time l.jpg
Generation Time

N = (log10Nf – log10No ) / .301

N Number of generations

Nf Final Concentration of Cells

No Original concentration of cells

.301 Conversion Factor to Convert Log2 to Log10


What is a logarithm l.jpg
What is a Logarithm?

  • Logarithm is a functionthat gives the exponent in the equation bn = x. It is usually written as logbx = n.

  • For example:

    34 = 81 Therefore log3 81 = 4


Example 1 n log 10 n f log 10 n o 301 l.jpg
Example 1N = (log10Nf – log10No ) / .301

Measure Culture at 9:00 a.m. 10,000 cells / ml

Measure Culture at 3:00 p.m. 100,000 cells / ml

Calculate N

N = (log10Nf – log10No ) / .301

N = (5-4)/0.301

N = 1/0.301

N = 3.33 Generations in 6 Hours

We Know: 6 Hours = 360 Minutes

Therefore: Generation Time = 360 Minutes / 3.33 Generations

N = 108 Minutes to Generate


Example 2 n log 10 n f log 10 n o 301 l.jpg
Example 2N = (log10Nf – log10No ) / .301

Measure Culture at 9:00 a.m. 10,000 cells / ml

Measure Culture at Noon 1,000,000 cells / ml

Calculate N


Example 2 n log 10 n f log 10 n o 30116 l.jpg
Example 2N = (log10Nf – log10No ) / .301

Measure Culture at 9:00 a.m. 10,000 cells / ml

Measure Culture at Noon 1,000,000 cells / ml

Calculate N

N = (log10Nf – log10No ) / .301

N = (6-4)/0.301

N = 2/0.301

N = 6.64 Generations in 3 Hours

We Know: 3 Hours = 180 Minutes

Therefore: Generation Time = 180 Minutes / 6.64 Generations

N = 27 Minutes to Generate


Example 3 n log 10 n f log 10 n o 301 l.jpg
Example 3N = (log10Nf – log10No ) / .301

Measure Culture at 9:00 a.m. 2000 cells / ml

Measure Culture at 1:00 p.m. 18,000 cells / ml

Calculate N


Example 3 n log 10 n f log 10 n o 30118 l.jpg
Example 3N = (log10Nf – log10No ) / .301

Measure Culture at 9:00 a.m. 2000 cells / ml

Measure Culture at 1:00 p.m. 18,000 cells / ml

Calculate N

N = (log10Nf – log10No ) / .301

N = (4.25-3.30)/0.301

N = .95/0.301

N = 3.16 Generations in 4 Hours

We Know: 4 Hours = 240 Minutes

Therefore: Generation Time = 240 Minutes / 3.16 Generations

N = 75.9 Minutes to Generate

N = 1.27 Hours to Generate




Slide21 l.jpg

Typical bacterial exponential Growth Curve. In a rich culture medium bacteria, grown under aerobic conditions, achieve a final concentration of 2-5 x 109 cells per ml in about 12-18 hours. Although plotted on a different time scale the human growth curve looks the same; the human population at similar points on the growth curve are shown in red.


Remember the four main stages l.jpg
Remember the Four Main Stages

  • Lag Phase

    Initial Phase / Metabolic Activities

  • Exponential Phase

    2nd Phase / Optimum Growth / Doubling

  • Stationary Phase

    3rd Phase / Exhaustion of Nutrients / Accumulation of Wastes

  • Death Phase

    Final Phase / Continued Accumulation

    90% of Cells Die, then 90% of Remaining Cells Die, etc.


Quantification of bacteria l.jpg
Quantification of Bacteria

  • Cell Numbers

  • Total Mass of the Population

  • Population Per Media

    cells / ml or cells / gram

  • Direct County Methods and Indirect Counting Methods


Direct counting methods l.jpg
Direct Counting Methods

  • Normally Viable Counts

  • Remember that a Colony Starts Out as 1 Bacteria that Reproduces

  • Colonies May Not All Be The Same Size


Types of direct measurements l.jpg
Types of Direct Measurements

  • Plate Count

    a. Spread (Streak) Plate

    b. Pour Plate

    2. Direct Observation on Slides

    a. Petroff-Hausser Chamber Slide

    3. Filtration

    4. Most Probable Number


Slide26 l.jpg

Direct Count

Spread or Streak Plate



Slide32 l.jpg

Direct Count

Pour Plate





Slide37 l.jpg

Direct Method

Filtration


Most probable number l.jpg
Most Probable Number

  • Statistical Procedure used to estimate the number of bacteria that will grow in liquid media.

  • Gives a 95% probability that the bacterial numbers will fall within a certain range.


Indirect measurements l.jpg
Indirect Measurements

Turbidity

a. No turbidity = < 107 cells/ml

b. Slight = 107 – 108 cells/ml

c. High = 108 – 109 cells/ml

d. Very High = > 109 cells/ml

Metabolic Activity

Dry Weight







Cardinal temperatures l.jpg
Cardinal Temperatures Levels

  • Minimum Temperature

  • Optimum Temperature

  • Maximum Temperature



Slide50 l.jpg


Classification of bacteria by ph requirements l.jpg
Classification of Bacteria by pH Requirements Levels

  • Acidophiles 1.0 to 5.5

  • Neutrophiles 5.5 to 8

  • Alkalophiles 8.5 to 11.5

  • Extreme

    Alkalophiles > = 10.0






Chemical requirements for bacteria l.jpg
Chemical Requirements dry food.for Bacteria

  • Water (80-90%)

  • Carbon (Backbone of Hydrocarbons)

  • Nitrogen (Amino Acids & Vitamins)

  • Sulfur (Amino Acids &Vitamins)

  • Phosphorus (Nucleic Acids, ATP)

  • Minerals (Fe, Cu, Mg, etc. / as Cofactors)

  • Oxygen (aerobes only)



Slide60 l.jpg

Special Culture Techniques dry food.

Gas Pack Jar Is Used for Anaerobic Growth


Slide61 l.jpg

Special Culture Techniques dry food.

Candle Jar


Slide63 l.jpg

Peritoneal Fluid Mixed  dry food.Anaerobic Infection


Types of media l.jpg
Types of Media dry food.

  • Media can be classified on three primary levels

    1. Physical State

    2. Chemical Composition

    3. Functional Type


Physical states of media l.jpg
Physical States of Media dry food.

  • Liquid Media

  • Semisolid

  • Solid (Can be converted into a liquid)

  • Solid (Cannot be converted into a liquid)


Liquid media l.jpg
Liquid Media dry food.

  • Water-based solutions

  • Do not solidify at temperatures above freezing / tend to be free flowing

  • Includes broths, milks, and infusions

  • Measure turbidity

  • Example: Nutrient Broth, Methylene Blue Milk, Thioglycollate


Semi solid media l.jpg
Semi-Solid Media dry food.

  • Exhibits a clot-like consistency at ordinary room temperature

  • Determines motility

  • Used to localize a reaction at a specific site.

  • Example: SIM for hydrogen sulfide production and indole reaction


Solid media l.jpg
Solid Media dry food.

  • Firm surface for discrete colony growth

  • Advantageous for isolating and culturing

  • Two Types

    1. Liquefiable (Reversible)

    2. Non-liquefiable

  • Examples: Gelatin and Agar (Liquefiable)

    Rice Grains, Cooked Meat Media,

    Potato Slices (Non-liquefiable)


Chemical composition of culture media l.jpg
Chemical Composition of Culture Media dry food.

  • Synthetic Media

    • Chemically defined

    • Contain pure organic and inorganic compounds

    • Exact formula (little variation)

  • Complex or Non-synthetic Media

    • Contains at least one ingredient that is not chemically definable (extracts from plants and animals)

    • No exact formula / tend to be general and grow a wide variety of organisms


  • Selective media l.jpg
    Selective Media dry food.

    • Contains one or more agents that inhibit the growth of a certain microbe and thereby encourages, or selects, a specific microbe.

    • Example: Mannitol Salt Agar encourages the growth of S. aureus.


    Differential media l.jpg
    Differential Media dry food.

    • Differential shows up as visible changes or variations in colony size or color, in media color changes, or in the formation of gas bubbles and precipitates.

    • Example: Spirit Blue Agar to detect the digestion of fats by lipase enzyme. Positive digestion (hydrolysis) is indicated by the dark blue color that develops in the colonies.


    Slide75 l.jpg

    Growth of dry food.Staphylococcus aureus on Manitol Salt Agar results in a color change in the media from pink to yellow.


    Enrichment media l.jpg
    Enrichment Media dry food.

    • Is used to encourage the growth of a particular microorganism in a mixed culture.

    • Ex. Manitol Salt Agar for S. aureus


    Microbes are managed and characterized by implementing the five i s l.jpg
    Microbes are Managed and Characterized by Implementing the Five I’s

    • Inoculation

    • Incubation

    • Isolation

    • Inspection

    • Identification


    Inoculation l.jpg
    Inoculation Five I’s

    • Sample is placed on sterile medium providing microbes with the appropriate nutrients to sustain growth.

    • Selection of the proper medium and sterility of all tools and media is important.

    • Some microbes may require a live organism or living tissue as the inoculation medium.


    Incubation l.jpg
    Incubation Five I’s

    • An incubator can be used to adjust the proper growth conditions of a sample.

    • Need to adjust for optimum temperature and gas content.

    • Incubation produces a culture – the visible growth of the microbe on or in the media


    Isolation l.jpg
    Isolation Five I’s

    • The end result of inoculation and incubation is isolation.

    • On solid media we may see separate colonies, and in broth growth may be indicated by turbidity.

    • Sub-culturing for further isolation may be required.


    Inspection l.jpg
    Inspection Five I’s

    • Macroscopically observe cultures to note color, texture, size of colonies, etc.

    • Microscopically observe stained slides of the culture to assess cell shape, size, and motility.


    Slide85 l.jpg

    FYI Five I’s


    Identification l.jpg
    Identification Five I’s

    • Utilize biochemical tests to differentiate the microbe from similar species and to determine metabolic activities specific to the microbe.

    • Utilize immunologic tests and genetic analysis.

    The Major Purpose of the 5 I’s is to Encourage Growth of a Microorganism so that the Lab Worker Can Determine the Type of Microbe, Usually to the Level of Species.


    ad