The Development of Microbiology

prokaryotic, unicellular

prokaryotic "small bacteria"

described by Howard Taylor Ricketts in 1909. Small bacteria.

These tiny bacteria can barely be seen with the light microscope, transmitted among humans by arthropods.

They are cultivated only on/in living tissues such as fertilized egg.

Some are pathogenic: Rocky Mountain Spotted Fever, Typhus Fever

half the size of rick. Can not be seen with the light microscope. It can be cultivated on artificial media. One species causes the gonorrhealike disease known as chlamydiae but symptoms milder than gonorrhea

smaller than chlamydiae. Smallest known bacteria. Can be cultivated outside living tissues in artificial lab media.

Prokaryotic but have no cell wall.

One form of pneumonia is due to mycoplasma; also a type of sexually transmitted disease is a mycoplasma disease.

If eat raw, home-grown vegetables, may get mycoplasma from fertilizer (though very rare)

Former name "blue-green algae". Today, microbiology considers them closely related to bacteria than to algae, however they are not regarded as true bacteria. Major biochemical, structural and physiological differences with other algae types.

Prokaryote; possess light-trapping pigments (Photosynthetic)

Many of the pigments are blue, but some are red, black, green, or yellow.

Mainly occur as unicellular; some are filamentous organisms.

Protozoan (singular). Eukaryotic, unicellular. No cell wall.

means first animals. Few species are photosynthetic (e.g. euglena), but most obtain their food (nutrients) from preformed organic matter.

• Thousands species known; only few dozen are pathogenic such as:
• malaria (Plasmodium) - #1 in number infested in world; mosquito vector
• sleeping sickness (Trypanosoma) - usually tropicaland subtropical disease

• They are classified into groups according to their movement:
• cilia (short) e.g. paramecium
• flagella (long) e.g. euglena
• pseudopodia e.g. amoeba
• gliding

Fungus (singular). Eukaryote, multicellular (except for yeast which is unicellular).

Mycology is the study of fungi.

Have cell wall which contains chitin, a carbohydrate not found in the plant cell wall which is composed of celluose.

Molds make up large part of fungi. Penicillin (PCN) is derived from bread mold.

Yeast under microscope look like large bacteria; 8 micrometer in size (average bacteria size is 1-5 micrometer)

Responsible for the fermentation of wine, beer, production of bread.

In ecology, bacteria and fungi are main decomposers (i.e. breakdown organic molecules).

Certain fungi are pathogenic: yeast infection, athlete's foot, thrush. Some are killers e.g. fungal infection of respiratory tract. Treatment of fungal infection/disease is usually longer duration than treatment for bacteria.

Eukarytic, unicelleluar, cell wall

• Two types of unicellular algae:
• diatoms - marine, main source of foods in oceans; photosynthetic
• dinoflagellates - photosynthetic; major component in world's food chain

Acellular.

They do not grow, they show no activity (replication) until enter living host.

They consist of nucleic acid, either DNA or RNA (classification method) surrounded by a sheath of protein. Many are responsible for many diseases: polio, measles, chicken pox, influenza, hepatitis.

Viruses can infect bacteria: bacteriophage

Virology - study of viruses is under umbrella of microbiology.

Taxonomy Carolus Linnaeus: Systema Natura, plants and animals.

In 1866, the German naturalist Ernst Haeckel, separated microorganisms from plantae and animalia. He coined the term protista for microorganisms and placed fungi, protozoa and algae in a kingdom.

• In 1969, Robert Whittaker of Cornell Univ. proposed a system that was widely accepted and it was further expanded by Lynn Margulis of Boston Univ: the five kingdoms.
• Domain >> kingdom >> phylum >> class >> order >> family >> genus >> species

fundamental rank in taxonomy is species

Micrometer.

Microorganisms range in size from relatively large (almost visible) protozoa (100 micrometer) doen to incredibly tiny viruses (0.01 micrometer).

Yeasts are commonly about 8 micro in diameter.

Most bacteria are about 1-5 micro in length. The largest bacteria reach 20 micro.

• Rickettsiae: 0.5 micro
• Chlamydia: 0.25 micro
• Viruses: nanometer= billionth of a meter.
• Smallpox virus about 250 nano=0.25 micro.
• Polio virus about 20 nano.

Light microscope Total mag. Resolving Power RP = lambda/2NA where NA = numerical aperture

"Cell" is "basic structural and functinal unit of all living organisms."

• All living things are made of cells:
• unicellular: archaea, bacteria, yeast, protozoa
• multicellular: animals, plants, fungi (except yeast)

• Two types of cells:
• eukaryote (true nucleus): fungi, animals, platns, protozoa, yeast. Eukaryote cells have membrane-bound organelles.
• prokaryote (before nucleus): archaea, bacteria. All prokaryotes are unicellular. Prokaryote do NOT have membrane-bound organelles; only have nuclear region and not membrane-bound

English scientistmade the microscope widely known and accepted. First to use term "cell" (basic unit of life) from study of cork (like a jail cell)

Netherland (1670s). Selfish since did not share technology/knowledge.

His lenses could magnify 200X; 300 year old specimens still good.

Wrote several letters to the Royal Society (London); in some of the letters, he included detailed descriptions of protozoa (Paramecium, Amoeba), bacteria (shapes). Perfectly preserved specimen.

• cocci - spherical
• bacilli - rod-shaped
• spirals - spirals or comma shaped

• prefixes:
• staph - cluster
• diplo - two
• strepto - chain

Swedish botanist Plants and Animals were classified. His book Systema Naturae published in 1735.

• Domain: Archaea (extreme environments), Bacteria, Eukaryota
• Kingdom
• Phylum/Division (for bacteria and plants)
• Class
• Order
• Family
• Genus
• Species
• -strain, serotype

• 4th. Century B.C. Aristotle wrote that flies, worms and other small animals arose from decaying matter without the need of parent organisms
• Spontaneous Generation - Lifeless substances could give rise to living creatures.

was one of the first to dispute the spontaneous generation with experiments using flies, eggs, maggots and kars/flasks with broth/meat. Some flasks completely open which developed maggots; others covered with fine lace which produced NO maggots

Redi: flies have reproductive organs, lay eggs, and eggs hatch to maggots.

In 1670s, he performed series of tests (experiments); his work was one of history's first experiment in biology.

In 1748 British scientist named John Needham, put forth/supported the notion that microorganisms arise by spontaneous generation. Disputed Redi's experiments.

He performed several experiments. He boiled broth, covered, returned to find organisms -- even on covered flasks.

In 1767, Spallanzani, an Italian scientist, criticized Needham's work.

He performed several experiments. Boileed broth longer; sealed by melting glass (hence no organisms). Other flasks left open (filled with organisms); others covered with loose covering (som organisms). Questioned by Needham due to long boiling time and seal; Needham argued that killed all chance of life.

His experiments did not settle the spontaneous generation

Disease Transmission: Ignaz Smmelweis, Hungarian physician. In 1847, his recommendation (hand washing in chlorine water) stopped the spread of disease.

British Physician, traced the source of Cholera (Vibrio cholerae, comma-shaped bacteria) to the municipal water supply of London during an 1854 outbreak. His recommendation was adopted (avoid drinking the contaminated water) and the spread of the disease was halted.

From intelligent guess not from experiments.

Yeast: role of yeasts in fermentation. Sour Wine "sick wine" Microorganisms as the agents of change. In 1857 he wrote a paper on the souring of milk by bacteria and he implied that microorganisms were related to human illness.

Concluded that agent for fermentation is yeast; agent for change to sour wine/milk is bacteria

He set down the foundation for the Germ Theory of Disease. He showed that where disease rampant, the air was full of microorganisms, but where disease was uncommon, the air was clean. He conducted his own exp. S-shaped neck (Swan-neck) flask.

Daughter Jeanne died from Typhoid Fever which is caused by Salmonella typhi (rod-shaped, gram-)

Pasteur verified the proof of the germ theory (by Koch) and gone a step further, he reported that bacteria were temp-sensitive, because chicken didn't acquire anthrax (via Bacillus anthracis) at their normal body temp (42 C), but did so when the animals were cooled to 37 C.

• In 1880: The basis for the use of vaccine
• experimented with inoculations of chicken by cholera Vibrio cholerae). Tried to develop enfeebled (weakened with acidic solution) bacteria. Injected weakened Vibrio cholerae to chickens; then exposed chickens to live Vibrio cholerae; chickens did NOT develop cholera.

In 1881, he applied the principle to anthrax to protect sheep against disease. In 1885, Pasteur reached the zenith of his career: he immunized a young boy against the rabies disease.

Pasteur died in l818

specific microogranisms cause specific diseases

• Koch four postulates stated:
• 1. The microorganism that causes a disease must be found in all organisms suffering from the disease. Conversely, the microorganism must not be found in healthy organisms.

2. The microorganism must be isolated from a diseased organism and grown in a pure culture.

3. The microorganism from the pure culture should cause the disease when introduced to healthy organisms.

4. The microorganism must be reisolated from the diseased, then-healthy organisms, and the microorganism is to be identified as being identical to the original specific pathogenic microorganism.

A country doctor from Germany.

He gave the definite proof of the germ theory of disease. His primary interest was anthrax (Bacillus anthracis, rod-shaped, gram-, spore-former), a deadly blood disease in cattle and sheep.

• 1875 injected healthy mice with blood of diseased animals. Mice autopsies showed that similar symptoms appeared. Noted that rod-shaped bacteria then present in mice blood.
• Placed isolated bacilli (from mice blood) in sterile medium
• Noticed that bacilli bacteria multiplied and in process produced toxic byproducts. Since nutrients consumed and toxic byproducts present, bacteria changed different state to a spore (as described by Cohn)
• Took spores and injected into healthy mice; spores changed state to vegetative form; symptoms present. Autopsies showed rod-shaped bacteria present. Developed pure culture (contains only one-kind of organism)

• four postulates stated:
• 1. The microorganism that causes a disease must be found in all organisms suffering from the disease. Conversely, the microorganism must not be found in healthy organisms.
• 2. The microorganism must be isolated from a diseased organism and grown in a pure culture.
• 3. The microorganism from the pure culture should cause the disease when introduced to healthy organisms.
• 4. The microorganism must be reisolated from the diseased, then-healthy organisms, and the microorganism is to be identified as being identical to the original specific pathogenic microorganism.

Pure Culture Technique. Colony contains millions of just one kind of bacteria.

Koch (around 1882) he isolated the tubercle bacillus. Koch also reached the heigt of his influence in 1880s. Isolated tubercle (Mycobacterium tuberculosis) in 1882, in 1883 went to Egypt & India and worked on cholera, he isolated the comma shaped bacteria and confirmed the suspicious first raised by John Snow in 1854, that water transmitted the disease. Koch also studied malaria (Plasmodium), Plague (Yersinia pestis), and sleeping sickness (Trypanosoma). His work with tuberculosis gained him the 1905 Nobel Prize in physiology/medicine. He died of a stroke in 1910 at the age of 66.

In 1884, George Gaffky cultivated the typhoid bacillus (Salmonella typhi).

1884 Friedrich Loeffler isolated the diphtheria bacillus (Corynebacterium diphtheriae).

of Pasteur's group, proved that diphtheria to be caused by a toxin that the bacillus produced in the body. Determined toxin to be cause of disease. Led to development of anti-toxin.

Later Koch's assoc., Emile Von Behring, was the first to successfully treat diphtheria by injecting antitoxin. Von Behring was awarded the first Nobel Prize in physiology/medicine.

In 1889,Koch's assoc., Shibasaburo Kitasato (Japanese scient.) successfully cultivated the tetanus bacillus: Clostridium tetani (anaerobic, rod-shaped, gram+, spore former).

• cause toxin (neurotoxin); purified in BoTox which has medical in addition to cosmetic purposes: stuttering, cross-eyedness
• Contamination of canned foods allows bacteria to produce toxin

In 1884, Emile Metchnikoff (Ukranian Scient.) one of Pasteur's assoc. was the first to publish an account of phagocytosis.

In 1878, the Oil immersion lens was introduced by Ernst Karl Abbe (German Physicist).

Oil immersion lens (100x) with standard eye-piece (10x) = 1000x magnification

Eight years later he invented the system of lenses and mirrors known as Abbe Condenser (condenses and concentrates light).