North Carolina Science Olympiad2010-2011

Rashmi Chandra, PhD

Event DescriptionIncludes (but not limited to): Types of microbes Microbe Structure Diseases caused by microbes Benefits of microbes Identification of baker’s yeast, ciliates, amoebae,

lichen, green algae, and diatoms Parts of a microscope Calculation of scale and conversion of metric units

Rules

Team of 2 students Things to Bring:One 8.5” X 11” sheet of two-sided notesNon-programmable calculator Z87 chemical splash goggles Pencil/Pen/Eraser/Ruler

Competition

Stations or written test Time 50 minutes Similar topics for Division B and C, but level of test

for Division B will be at the Middle school level.

Types of MicroscopesLight Microscope: Light passes through lenses and magnifies objects.

Fluorescence Microscope: Light of known band-width excites a fluorescent

molecule in a sample, which is detected when it emits light of a longer wavelength

Scanning Electron Microscope: Electron beam magnifies objects up to two million times

Transmission Electron Microscope: Electron beam passes through very thin specimens

Light MicroscopeLight from an incandescent

source

Passes through a lens (condenser ) located beneath the stage

Goes through the specimen

Goes through the objective lens

Goes to the eye via a second magnifying lens (eyepiece)

Scanning Electron Microscope

Eye of Fruit fly

Scale

Obtain an idea of the scale of objects at:http://learn.genetics.utah.edu/content/begin/cells/scale/

Metric Conversion

The Three Domains

Bacteria

Archaea

Eukaryota

Image: http://evolution.berkeley.edu/evosite/evo101/IIAFamilytree.shtml

Microbe

Prion: Protein molecule Virus: Can only exist in host cells Bacteria: Single-celled prokaryotic organisms Archaea: Single-celled with characteristics similar to

prokaryotes and eukaryotes Protist: Eukaryotic, unicellular or multicellular

organisms with a very simple cellular structure Lichen: Multicellular; symbiotic relationship between

green algae or cyanobacterium and fungus Fungus: Eukaryotic; includes microorganisms such as

mold and yeast

Microbe: Microscopic organism

Prions Proteinaceous infectious

particle Nucleic acids not needed for

infectivity Cellular prion protein (PrPC) is

present on the cell surface. The mutant protein, PrPSC has an altered secondary structure. When PrPSC

interacts with the normal protein ,aggregation occurs.

Image: http://www.ier.tokushima-u.ac.jp/e/saibou.htm

Prions and Disease Fatal diseases caused by

sporadic mutations, genetics or infection Creutzfeldt-Jacob disease

(CJD, shown in Figure) Bovine spongiform

encephalopathy Scrapie of sheep

Neurodegenerative Brain develops lesions,

vacuoles, amyloid protein deposits, astrogliosis

Image: http://www.cjdinsight.org/Deana/sporadiccjd.html

Normal CJD

Viruses

Need host cells for reproduction

Infect bacteria, plants and animals

Diverse shapes Genetic material: DNA

or RNA Protein capsid Envelope

Image: http://faculty.southwest.tn.edu/rburkett/viruses_and_prions.htm

Image: http://en.wikipedia.org/wiki/File:Viral_infections_and_involved_species.png

Bacteria

Prokaryotic Unicellular, microscopic No membrane bound

organelles Aerobic, anaerobic or

facultative anaerobes Diverse and numerous

Image: http://chsweb.lr.k12.nj.us/mstanley/outlines/bacteria/bacteria.htm

Division C: Bacterial Shapes

Shape affects motility, activity, and survival Cocci: spherical (Streptococcus) Bacilli: rod-shaped (Salmonella) Spirillum: spiral or helical (Leptospira) Filamentous: complex forms (Leptothrix)

Div. C: Gram (-) and Gram (+) bacteria

Gram Positive

Gram Negative

Gram Negative Gram Positive

Thin inner peptidoglycan wall + outer wall Thick peptidoglycan cell wall

Bacteria do not retain crystal violet stain: appear red

Bacteria retain crystal violet stain:appear purplish

Bacterial Diseases Streptococcus Salmonella Diptheria Bacterial Meningitis Pneumonia Cholera Bubonic plague

Salmonella typhimunium (red) invading cultured human cells.

Image: http://microbewiki.kenyon.edu/index.php/Salmonella

Beneficial bacteria

Yogurt and cheese Fermentation Nitrogen fixation Flora of gut Decomposition of

plants and animals Oil-eating bacteria

help clean up oil spills Etc

Images: http://bioweb.uwlax.edu/bio203/s2008/jaedike_alic/bacteriaandhumans.htm

Archaea Archae = ancient Can survive under extreme

conditions of salinity, temperature and pH

Microscopic Spherical or rod-shaped;

occasionally triangular or square

Membrane lipids have ether linkages

Images: http://www.ucmp.berkeley.edu/archaea/archaeamm.html

Comparison of Archaea with Bacteria and Eukaryotes

Characteristic of Arachaea Similarity toCapable of growing in extreme temperatures; metabolic processes

Bacteria

No cell membrane or introns; circular DNA, 70S ribosomal subunits present

Bacteria

Methionine as initiator tRNA, histones in DNA, ribosomes sensitive to diptheria toxin

Eukaryotes

Cell membranes contain L-glycerol, ether linkage, branched isoprenes

Neither bacteria nor eukaryotes

Benefits from Archaea

Ammonia oxidation in soil Carbon and Nitrogen cycles Production of heat resistant enzymes used in laundry detergents No harmful effects known

Image:http://www.nsf.gov/news/news_images.jsp?cntn_id=104466&org=NSF

Kingdom Protista

Eukaryotic Unicellular or multicellular Protozoans, algae or fungus-like Absorb, ingest or

photosynthesize food

Protists Autotrophs and heterotrophs

Apicomplexans: Plasmodium Diplomonads: Giardia Gymnamoebas Parabasalids: Trichomonas Kinetoplastids: Trypanosoma Oomycetes: Water mold, white rust, mildew Plasmodial (acellular) Slime Molds Cellular Slime Molds Euglenoids: Euglena Dinoflagellates Ciliates: Paramecium Diatoms Foraminifera Radiolarians

Algae

Contain chlorophyll or related pigments for photosynthesis

Habitats: marine, freshwater, terrestrial, endosymbionts

Unicellular or multicellular Body is called thallus Asexual or sexual

reproduction

Image: http://www.daviddarling.info/encyclopedia/A/algae.html

Algae: Uses and Diseases

Eaten as entrée Alginate, agar and

carrageenan have numerous uses in food, pharmaceutical, medical and other industries

Toxic substances produced by algae can cause human diseases, primarily via eating contaminated shellfish

Image: http://botany.si.edu/projects/algae/economicuses.htm

Lichens

Symbiotic relationship between fungus and algae/cyanobacteria

Cell structure Types Reproduction

Image: http://www.buffelskloof.info/Lichens.htm

Uses of Lichens

Natural dyes for wool and fabric

Food for caribou Determination of air

quality Anti-viral and anti-

bacterial medications Litmus paper dye

Fungi

Eukaryotic Cell structure Reproduction Types: saprophytes,

parasites, mycorrhizal Uses (bread, drugs, etc) Diseases (e.g. ringworm)

Beneficial Fungi

Decompose dead plants

Help plants absorb water and nutrients

Farmed by ants for food

Eaten by humans Source of medicines

Fungal Infections

• Superficial, localized skin conditions or deep tissue infections • Caused by exposure to spores• May or may not be transmitted• Categorized by:

• part of the body affected• how deeply the fungus penetrates the body • the organism causing the infection, • the form(s) that the fungi take

Location Fungal Disease Comments and Symptoms

Superficial Yeast infectionCandida albicans and other species of Candida

Due to the overgrowth of yeast which are part of the normal flora; thrush (mouth), diaper rash

Fungal (dermatophyte)Trichophyton, Microsporum, and Epidermophytonspecies.

Fungus feeds on keratin. Causes reddening, peeling, blistering, and scaling of the skin, itching, deformation and brittleness of affected nails, and brittle hair.

Systemic (deep) Aspergillosis, caused by Aspergillus fumigatus or several other Aspergillusspecies

Fungi commonly found in soil, plants, and house dust. They can cause fungal masses in the sinuses and lungs and, in some cases, can spread to the brain and bones.

Pneumocystis pneumonia, caused by Pneumocystis

Causes pneumonia and/or septicemia. Fungal lung infections are more likely to be severe in people who have underlying lung disease and/or compromised immune systems such as those with HIV/AIDS

Division C: Spores Produced by bacteria, protists

and fungi Resting stage formed under

conditions of stress Asexual reproduction Resistant to temperature,

chemicals and desiccation Exospore: Formed by budding of

a vegetative cell Endospore: Formed inside the

parent cell

Images: http://www.microbiologyonline.org.uk/about-microbiology/introducing-microbes/bacteriaReed et al., J. Bacteriol (1980) Volume 141, pp 908-913

Endospore

Exospore

Division C: Cysts Dormant stage of bacteria

or protist Thick walls Protective Resistant to chemicals,

desiccation and UV light, but not high temperature

No reproductive function Cause water-borne illness

Image: http://www.microbiologytext.com/index.php?module=Book&func=displayarticle&art_id=70

Microbes and Food Spoilage What causes food to spoil? Prevention

Pasteurization Handling Temperature of storage Moisture

Some organisms that cause food spoilage: Botulism Mold Clostridium Salmonella

http://home.pacific.net.hk/~ppleung/Chem/spoilage.htm

Microbes and Food Preservation

When microbes ferment food, they create an environment that is toxic to them, as well as other microbes. This helps to preserve the fermented food.

Image: http://davesgarden.com/guides/articles/view/1641/

Role of Microbes in Commerce

Production of Food: Yogurt Cheese Bread Vitamins Beer Monosodium glutamate Citric acid Chocolate Meat products

Used in Manufacture of:• Ethanol• Acetone• Butanol• Antibiotics• Vaccines• Fibers• Biofertilizers• Biopesticides• Enzymes

Growth CurvesPhases of Growth:Lag:

Microbes adapt to new environmentCell population does not increase

Log:Microbes start dividingPopulation increases exponentially

Stationary:Steady stateCell division approx. = Cell death

Decline/death:Depletion of nutrientsIncrease in waste productsConditions inhospitable, leading to cell death

Image: http://www.science-projects.com/SteadyState/SSProjects.htm

Resources http://www.edu.pe.ca/southernkings/microbe.ht

m http://www.microbeworld.org/ http://microbiologyprocedure.com/index.htm http://TomVolkFungi.net/ http://www.lichen.com/biology.html

Division B http://commtechlab.msu.edu/sites/dlc-me/