biology 120 lecture 1 2011 2012

BIOLOGY 120 (MICROBIOLOGY)

Lecture 1(Introduction to Microbiology)

Parungao-Balolong 2011-2012Thursday, June 16, 2011

MICROBIOLOGY : Definition

Deals with the study of microorganisms

Morphology, Interaction, Physiology, Genetics, Classification, etc.


MICROORGANISMS : Definition

Living organisms and agents too small to be seen clearly by the unaided eye

Organisms with a dimension of 1mm or less


BACTERIA

Simple unicellular organisms

Prokaryotes

Exhibits major forms:

Coccus

Bacillus

Spirals

etc (others) Parungao-Balolong 2011-2012Thursday, June 16, 2011

BACTERIA

Motile or Non-motile

Flagella

Cilia

etc (others)

Reproduction: Binary Fission


BACTERIA

Cell Wall: Peptidoglycan

Acquiring Nutrition:

Free-living

Parasitic

Saprophytic

PhotosyntheticParungao-Balolong 2011-2012

Thursday, June 16, 2011

ARCHAEBACTERIA

Prokaryotes

Lacks Peptidoglycan cell wall

Found in extreme environments


ARCHAEBACTERIA

3 MAJOR GROUPS

Methanogens

Extreme Halophiles

Extreme Thermophiles


FUNGI

EUKARYOTES

Unicellular (Yeasts)

Multicellular (Molds)

Forms visible mass called mycelia (mass of hyphae)

cell wall: chitin

Reproduction: Sexual or asexual


PROTOZOA

EUKARYOTES

Unicellular

Motility: psuedopods, flagella, cilia

Comes in various shapes and form

Free-living or Parasitic


ALGAE

Parungao-Balolong 2011-2012

Photosynthetic eukaryote

Form: unicellular, multicellular or colonial (cellular to filamentous)

Reproduction: sexual or asexual


ALGAE


Important producers in aquatic and freshwater ecosystems

Microscopic and macroscopic forms exists

Cell walls of most representative compose of cellulose


VIRUS


Acellular forms

Minute organisms, filterable

Visible with electron microscope

Can infect bacteria, plants, animals and humans


VIRUS


Contains either RNA or DNA enclosed by a protein coat and sometimes an additional lipid envelope

Reproduces only on a living host (obligate parasites)


VIROIDS


Infectious plant RNA (similar to introns)

Short strand of RNA with 300-400 nucleotides without protein coat

RNA is a closed, folded 3D structure (does not code for any protein)

Pathogenic to plants only damaging crops (e.g. potato = PSTV)

????


PRIONS


Proteinaceous, infectious particles

Causative agent of spongiform encephalopathies

Scrapie in sheep

Mad cow disease of cattle

Kuru in manThursday, June 16, 2011

PRIONS


INFECTED SHEEP/ COW

INGESTION OF UNDERCOOKED MEAT

DISEASE


COMPARISON OF SIZESORGANISM AVERAGE SIZE (diameter/length)

in nm)Thiomargarita namibiensis * 1, 000, 000Epulopiscium fishelsoni * 600, 000RBC 7, 000Oscillatoria (a cyanobacteria) 7, 000Escherichia coli 4, 000Rickettsia 475Nanoarchaeum equitans 400Poxvirus 450Mycoplasma genitalium 300Some nanobacteria 20Parvovirus 18Ribosomes 25-30Smallest mycoplasmas 150


COMPARISON OF GENOME SIZES

ORGANISM GENOME SIZE (number of base) pairs)Human 3120 million

Mouse 3000 millionRice 430 millionFruit Fly 120 millionYeast 12 millionEscherichia coli 4 millionProchlorococcus (a cyanobacteria) 1.66 millionRickettsia prowazekii 1.1 millionChlamydia trachomatis 1.1 millionMycoplasma genitalium 580, 000Nanoarchaeum equitans 490, 000Human mitochondrion 16, 500E. coli virus 5, 400


WHERE CAN YOU FIND THEM?

HABITAT APPROXIMATE POPULATION Garden Soil (surface) 9.7 x 106 per gramGarden Soil (30cm deep) 5.7 x 105 per gramLake water (shallow) 104 per mlLake water (deep) 102 per mlSeawater 1.1 x 103 per mlHuman skin 106 per m2

Human mouth 107 per mlHuman intestine 4 x 1010 per gramMilk 103 to 106 per mlCheese 108 per gramSunlit Surface FewAir Few


LOOKING BACK...The History of Microbiology


3000 years ago...

Discovery of Mycobacterium tuberculosis from Egyptian Mummies

Proof that “Microbes are already present even before the science to study them”


BREAKTHROUGHS IN THE SCIENCE OF MICROBIOLOGY

MICROSCOPY AND THE DISCOVERY OF MICROORGANISMS

CULTURE METHODS

GERM THEORY OF DISEASE

DEFENSE OR CONTROL OF MICROBES

MAJOR BREAKTHROUGHS: Virology and Molecular Methods


MICROSCOPY & DISCOVERY OF MICROORGANISMS

1677 (Anton Van Leeuwenhoek)

animalcules



1882 (Paul Erlich)

discovery of acid fast stain



1884: (Christian Gram)

Gram stain (2 groups of bacteria)


CULTURE METHODS

1882(Robert Koch)

solid culture media (basic technique of isolating pure cultures)

initially used potatoes to culture microbes


CULTURE METHODS

1887 (R. J. Petri)

modified culture techniques a by Koch and introduced Petri dish



1860 (Louis Pasteur)

microorganisms cause disease



1867 (Joseph Lister)

antiseptic in the practice of surgery



1876 (Robert Koch)

Koch’s Postulate



1796 (Edward Jenner)

vaccination (small pox)



1850 (Ignaz Semmelweis)

hand washing in preventing disease



1885 (Louis Pasteur)

Sterilization and Pasteurization



1900 (Walter Reed)

yellow fever is transmitted by mosquito



1910 (Paul Erlich)

salvarsan as cure for syphilis



1928 (Alexander Fleming)

penicillin antibiotic (a contaminant)


MAJOR BREAKTHROUGHS

VIROLOGY

1892 (Dmitri Iosifovich Ivanovski)

viruses in tobacco (“wildfire”)


MAJOR BREAKTHROUGHS

VIROLOGY

1899 (Martinus Beijerinck)

isolation of first virus


MAJOR BREAKTHROUGHS

MOLECULAR METHODS

1977 (Walter Gilbert & Frederick Sanger)

sequence of nucleotide in nucleic acid (base sequences)


MAJOR BREAKTHROUGHS

MOLECULAR METHODS

1983 (Kary Mullis)

polymerase chain reaction (PCR)


SPONTANEOUS GENERATIONThe Grand Microbiology Debate through Experimentation


SPONTANEOUS GENERATION

Production of mice required placing sweaty underwear and husks of wheat in an open-mouthed jar, then waiting for about 21 days, during which time it was alleged that the sweat from the underwear would penetrate the husks of wheat, changing them into mice


Francisco Redi (1668)

Believed that maggot developed from eggs laid by flies on the meat


John Needham (1745)

Heated infusion of chicken broth and corn, poured into covered “clean” flasks

Soon contaminated (turbid)

Said could only be due to spontaneous generation


Lazaro Spallanzani (1765)

Modified Needham’s experiment: the fluid was sealed in the flasks, and then boiled. noted that they did not show contamination if sterilized in the sealed flask

Proponents of spontaneous generation argued that Spallanzani had only proven that spontaneous generation could not occur without air


http://aportes.educ.ar/biologia/Experimentos+Spallanzani.jpg






Louis Pasteur (1859)


Louis Pasteur (1859)

Disproving the theory of spontaneous generation led to the development of effective sterilization procedures. The development of vaccines for the diseases anthrax, fowl cholera, and rabies


ROLE OF MICROBES


biology 120 lecture 1 2011 2012

Documents

spontaneous

microscopy

paul erlich

louis pasteur

robert koch

germ theory

protein coat

parungao