microbiology 2011 professor m. “it is, in fact, nothing short of a miracle that the modern...

MICROBIOLOGY 2011 PROFESSOR M. “It is, in fact, nothing short of a miracle that the modern methods of instruction

have not entirely strangled the holy curiosity of inquiry.” Albert Einstein

   A Light Microscope - the models found in most schools, use - compound lenses and light to magnify objects. The lenses bend or refract the sunlight or lights in a room, which makes the object beneath them appear closer. 1000 x magnification

Stereoscope - this microscope allows for binocular (two eyes) viewing of larger specimens. 40-70 magnification 

ELECTRON Developed in

1930’s Expensive Large structure Views electrons Images are B/W Higher resolution High radiation

exposure 2 million

magnification

LIGHT Developed 1590 Less expensive Smaller structure Views photons Images in color Lower resolution No radiation

exposure Magnifies 1-2,000

x

Scanning Electron Microscope - allow scientists to view a universe too small to be seen with a light microscope. SEMs don’t use light waves; they use electrons (negatively charged electrical particles) to magnify objects up to two million times. Three dimensional view.

Transmission Electron Microscope - also uses electrons, but instead of scanning the surface (as with SEM's) electrons are passed through very thin specimens. Two dimensional view.

SEM

http://www.ualberta.ca/~mingchen/images.htm

SEM

http://www.ualberta.ca/~mingchen/images.htm

TEM

http://www.ualberta.ca/~mingchen/images.htm

TEM

http://www.ualberta.ca/~mingchen/images.htm

14th century – Italy – lens ground; used for improving vision

1590 – Janssen brothers made 1st scope by placing two lenses in a tube.

1667 – Robert Hooke studies various objects with his microscope and publishes his results in Micrographia.

1675 – Anton van Leeuwenhoek uses a simple microscope with only one lens to look at blood, insects and many other objects. He was first to describe cells and bacteria, seen through his very small microscopes with, for his time, extremely good lenses.18th century – Several technical innovations make microscopes better and easier to handle, which leads to the use of microscopes becoming more and more popular among scientists. An important discovery is that lenses combining two types of glass could reduce the chromatic effect, with its disturbing halos resulting from differences in refraction of light.

1830 –Lister’s refinement reduces the problem with spherical aberration by showing that several weak lenses used together at certain distances gave good magnification without blurring the image.

Van Leeuwenhoek (1632 – 1723) 1st to see bacteria = Father of Microbiology; magnification of his lenses - 200-300x

Pasteur (1822- 1895) – fermentation; coined terms aerobe and anaerobe; heated fluids to kill bacteria that caused his wine to go bad = Pasteurization (only kills pathogens); made vaccines for animals

What is up with the fad in Pa. for ‘raw’ cow’s milk?

The bacteria must be present in every case of the disease.

The bacteria must be isolated from the host with the disease and grown in pure culture.

The specific disease must be reproduced when a pure culture of the bacteria is inoculated into a healthy susceptible host.

The bacteria must be recoverable from the experimentally infected host

1938 – Ernst Ruska develops the electron microscope. The ability to use electrons in microscopy greatly improves the resolution and greatly expands the borders of exploration.The Nobel Prize in Physics 1986 »

1981 – Gerd Binnig and Heinrich Rohrer invent the scanning tunneling microscope that gives three-dimensional images of objects down to the atomic level.The Nobel Prize in Physics 1986 »

1. Etiology – cause or theory of origin 2. Incidence – range of occurrence;

tendency to affect groups differently 3. Morbidity – % affected people/

population in a given time frame 4. Mortality - % deaths from given disease

within given time frame 5. Idiopathic – no known cause

6. Iatrogenic – caused by adverse effects of tx 7. Communicable disease - transmittable 8. Endemic – a few people always have a given

illness in a certain area (common cold) 9. Epidemic – many people in a given area are

sick with same disease at same time (flu) 10. Pandemic – a disease seen throughout an

entire country, continent or the world (HIV)

Primitive organism Binary fission for cell

division No membrane bound

organelles/ nucleus Has separating

membrane and cell wall

Ex: Bacteria and blue-green algae

Evolved; advanced True nucleus with a

membrane Cell division - mitosis Animal – meiosis Fungi, protozoa,

green/red/brown algae, plant and animal cells

Indigenous flora – microbes found growing on/ within our body every day

Pathogen – a disease causing microorganism

Host – The organism on/in which the parasite lives (its source of nutrition)

Parasite – a microorganism relies on host for its needs to the detriment of the host

Opportunistic infection – an organism that is able to cause a disease because the host’s health has been compromised

When a microorganism is growing but does not cause inflammatory changes in the location of the growth.

EX: Bacteria present in nasal passages. Nasal passages are free from signs and symptoms of bacterial presence. No redness, swelling, pain or heat in the area.

The bacteria is still transmittable.

Direct contact Indirect contact – fomite Droplet Airborne Vehicle – bad food, water Vector – flea, mosquito, tick, rats

Kingdom Phyllum Class Order Family Genus* Species*

◦ Species members share a basic genetic similarity and can interbreed and produce viable or fertile offspring.

http://en.wikipedia.org/wiki/Clostridium

Clostridium difficile Clostridium botulinum Clostridium sodellii Clostridium tetani Clostridium perfringens These 5 are the most commonly seen but

there are many others in this species…….

C. Acetobutylicum, C. argentinense C. aerotolerans

C. baratii, C. beijerinckii, C. bifermentans, C. botulinum, C. butyricum

C. cadaveris, C. cellulolyticum, C. chauvoei, C. clostridioforme

C. colicanis, C. difficile, C. estertheticum, C. fallax, C. feseri

C. formicaceticum, C. histolyticum, C. innocuum, C. kluyveri

C. ljungdahlii, C. laramie, C. lavalense, C. nigrificans, C. novyi

C. oedematiens, C. paraputrificum, C. perfringens, C. phytofermentans

C. piliforme, C. ragsdalei, C. ramosum, C. scatologenes, C. septicum

C. sordellii, C. sporogenes, C. sticklandii, C. tertium, C. tetani,

C. thermocellum, C. thermosaccharolyticum, C. tyrobutyricum

Definition: shape Bacilli Cocci Vibrios Spirallae Spirochete Check your handout

Cocci, round bacteria (Gram stained).

• What word describes the shape and arrangement of the cells in D?

Bacilli, rod-shaped bacteria.

Curved rods• What feature indicates that the cells in A

are capable of movement?

Single cell Paired cells Chains of cells Clusters of cells Color Size

Bacteria Fungal

◦ Yeasts – single cellMolds - filamentous

Rickettsiae Viral Protozoal Metazoal (helminths)

Metabolism◦ Physical & chemical processes involved in

maintaining life Growth Ability to reproduce Irritability (able to react to environment) Motion – gliding, flagella, axial filaments Protection

Light◦ Amount◦ Type

Temperature Moisture Food Availability Oxygen supply pH

Spore Capsules Flagella

Drug resistance

Endotoxins◦ Poison remains within the infected cell until it

disintegrates◦ May cause typhoid fever & bacillary dysentery

Exotoxins◦ Poison is excreted by the cell into the surrounding

area◦ May cause tetanus, gas gangrene, diphtheria and

scarlet fever

Gram negative cell wall Obligate intracellular pathogen

◦ Must live within a host cell Arthropod borne (vectors) Cat scratch fever, trench fever (lice vector)

Energy parasites – use ATP from host Gram negative cell wall Obligate intracellular pathogen Transmission is aerosol or direct contact Can cause pneumonia, inclusion

conjunctivitis, trachoma (blindness) as well as sexually transmitted infection.

Smallest of cellular microbes No cell walls, so have many shapes Gram stain ineffective because they have

no cell wall May be free living or parasitic Antibiotics that focus on inhibiting cell wall

synthesis are ineffective Ex: Mycoplasmic pneumonia