Introduction to microbiology. Classification and nomenclature of microorganisms. Course Introduction icon

Introduction to microbiology. Classification and nomenclature of microorganisms. Course Introduction

НазваниеIntroduction to microbiology. Classification and nomenclature of microorganisms. Course Introduction
Дата конвертации14.10.2012
Размер445 b.
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Introduction to microbiology. Classification and nomenclature of microorganisms.




Course Introduction

  • Instructor:

  • Dr Elena Romancenco

  • Department of Microbiology, Virology and Immunology

  • E-mail: eromancenco@yahoo.com

  • WEBSITE:

  • www.microbio.ukoz.com



Course objectives

  • List major groups of microorganisms and their habitats.

  • Overview and history of Microbiology.

  • Describe the system of scientific nomenclature used to name microorganisms.



Definition

  • Microbiology (mikros bios logos – small, live, study) study microorganisms and their activities.

  • Microbiology is the study of microorganisms usually less than 1mm in diameter which requires some form of magnification to be seen clearly.

  • Microbiology - study the organisms that can exist as single cells, contain a nucleic acid genome for at least some part of their life cycle, and are capable of replicating that genome themselves or getting replicated with the help of host cells



Branches of Microbiology

  • Bacteriology: study of bacteria

  • Mycology: study of fungi

  • Virology: study of viruses

    • Beijerinck, NE: discovered intracellular reproduction of TMV; coined the term “virus” (1899)
  • Parasitology: study of protozoa and parasitic worms



Branches of Microbiology

  • Immunology: study of immunity

    • Edward Jenner, UK: developed vaccination (1798)
    • Metchnikoff, RU: discovered phagocytes (1884)
    • Paul Ehrlich, DE: theory of immunity (1890)
  • Chemotherapy

    • Treatment of disease by using chemical means
    • Antibiotics produced naturally
    • Synthetic drugs
    • Paul Ehrlich (1878) – used arsenic compounds to fight disease


Branches of Microbiology

  • Chemotherapy

    • Alexander Fleming, Scotland (1928) discovered penicillin
    • Selman Waksman, Ukraine (1944) discovered streptomycin
  • Problems

    • Toxicity of drugs => Selective toxicity
    • Resistance of bacteria to drugs


Microorganisms are everywhere, but why is so important to learn about them?

  • Affect our lives in many different ways.







^ IMPORTANCE OF MICROORGANISMS

  • Microorganisms are the oldest forms of life.

  • Nutrient production & energy flow

  • Production of foods

  • Decomposition (bioremediation)

  • Without certain microorganism life could not exist; produce O2 and N2

  • Production of drugs & vaccines

  • Genetic engineering

  • Causing disease

  • Microorganisms have killed more people than have ever been killed in war.



Why Study Medical Microbiology?

  • The majority of serious diseases in humans (especially those of early childhood) are due to microbial infections.

  • Prior to the discovery of antibiotics and vaccines, a large proportion of children died before adulthood because of infectious disease.

  • Till 1900, the average life expectancy in the United States was 40 years of age.

  • In 2000 - 80 years, largely due to the near eradication of most serious early childhood diseases.

  • This trend is seen in the gap between developed and developing countries in terms of causes of death (mortality).



MICROBES

  • MICROBES includes all those living organisms that can not be viewed (seen) in any detail by the human eye.

  • Alternatively, a MICROBE is any living creature that must be examined with a magnifying lens in order to see its unique physical characteristics (size, shape, motility, color).



Microbes

  • Pathogen or pathogenic - capable of producing disease.

    • Though only a minority of microorganisms are pathogenic, practical knowledge of microbes is necessary for their treatment so is highly relevant to medicine and related health sciences.
  • Normal flora [normal microbiota] - not typically-disease-causing

        • microorganisms normally found in and on healthy individuals.
      • on the skin,
      • in the eyes,
      • in the nose,
      • in the mouth,
      • in the upper throat,
      • in the lower urethra,
      • in the lower intestine.






Microbiologists may be interested in various characteristics or activities of microbs and may study:

    • Microbial morphology
    • Microbial cytology
    • Microbial physiology
    • Microbial ecology
    • Microbial genetics and molecular biology
    • Microbial taxonomy


Classification of life



  • For many years, living organisms were divided into two kingdoms:

    • Animalia (animal) and
    • Plantae (vegetable).


Classification Schemes



  • But after 1800s, scientists realized that these two kingdoms could not adequately express the diversity of life.

  • Since the 1960s, the most widely used scheme - five kingdoms.

  • Viruses are separate group of biological entities, although not organisms in the same sense as Eukaryotes, Archaea and Bacteria.



Classification schemes, 5 kingdoms



Classification of Life

  • 3 major Domains of life

    • Bacteria
    • Archaea
    • Eukaryota (Eukarya)
  • The first two are Prokaryotes (Bacteria and Archaea)- without true nucleus, while the Eukaryotes all have a true nucleus in each cell.





Kingdom Monera

  • All organisms in the Kingdom Monera are prokaryotes.

    • lack nuclei and organelles
    • most of their cell walls are made of peptidoglycan (the exceptions are the archaebacteria).
  • The archaebacteria have cell walls that lack peptidoglycan, cell membranes that utilize different lipids, and ribosomes similar to those found in eukaryotes.

  • The bacteria (eubacteria-true bacteria) are characterized by how they metabolize resources, their means of motility, and their shape.

  • Most organisms in the Kingdom Monera reproduce through binary fission (asexual) or conjugation (sexual).



Bacteria

  • Most utilize flagella for movement.

  • Digestion is extracellular (outside the cell) and nutrients are absorbed into the cell.

  • Circulation and digestion in Kingdom Monera is accomplished through diffusion.



Bacterial Classification

        • by
  • Metabolism

  • Morphology (shape)

  • Staining, etc



According the metabolism

    • Autotrophs manufacture their own organic compounds.
    • Heterotrophs obtain their energy by feeding on other organic substances.
    • Saprophytes, a special kind of heterotroph, obtain energy by feeding on decaying matter.


According the symbiotic relationships with other organisms:

    • In parasitism, harm is caused to the host.
    • In commensalism, one organism benefits while the other is unaffected.
    • In mutualism, both organisms benefit.


According the respiration:

    • In obligate aerobes, the prokaryotes must have oxygen to live.
    • In obligate anaerobes, the organisms cannot survive in the presence of oxygen.
    • And in facultative anaerobes they can survive with or without oxygen.


According the shapes:

    • cocci (spherical),
    • bacillus (rod shaped), and
    • spirillum (spirals).


Classification of bacteria

      • Cocci
        • Micrococcus
        • Staphylococci
          • Irregular clusters of cocci
        • Diplococci
          • Pairs of cocci
        • Streptococci
          • Chains of cocci






Size of bacteria

  • Unit of microbial measurement

    •  micrometers (um)
      • 1 um being 10-6  m   or 0.000001 m(1/25,000 inch)
    • nanometers 
      • 1 nm being 10-9 or 0.000000001 m.
  •  

  • Pathogenic bacterial species vary from approximately 0.4 to 2 um in size





Taxonomy

  • Taxonomy is the classification of organisms. The most common system in use today is the Five Kingdoms:

  • Organisms in each kingdom are divided into phyla.

    • In each phylum, organisms are separated into classes.
    • In each class, organisms are segregated into orders.
    • In each order, organisms are divided into families.
    • In each family, organisms are separated by genus.
    • And finally, in each genus organisms are divided into species.
  • Just remember that King Philip Can Order For Genial Students.



Naming micoorganisms

  • Binomial (scientific) nomenclature

  • Gives each microbe 2 names

    • Genus - noun, always capitalized and may be abbreviated
    • species - adjective, lowercase, never abbreviated
    • A genus name may be used alone to indicate a genus group; a species name is never used alone
          • eg: Bacillus subtilis       B. subtilis
  • Both italicized or underlined

    • Staphylococcus aureus (S. aureus)
    • Bacillus subtilis (B. subtilis)
    • Escherichia coli (E. coli)


Nomenclature

  • Common or descriptive names (trivial names)

    • Names for organisms that may be in common usage, but are not taxonomic names
      • eg: tubercle bacillus         (Mycobacterium tuberculosis)
      • meningococcus (Neiserria meningitidis)
      • Group A streptococcus (Streptococcus pyogenes)


Eukaryotes



Prokaryotes

  • Kingdom - Monera

  • Domain - Bacteria

  • Phylum – Proteobacteria

  • Class – Gammaproteoba

  • Order – Enterobacteriale

  • Family – Enterobacteriace

  • Genus – Escherichia

  • Species Escherichia coli



"The role of the infinitely small in nature is infinitely large"

  • Louis Pasteur



Historical Perspectives



Historical



Pioneers of Microbiology

  • Robert Hooke, UK (1665)

    • Proposed the Cell Theory
    • Observed cork with crude microscope
    • All living things are composed of cells
  • Spontaneous generation

    • Some forms of life could arise spontaneously from non-living matter
  • Francesco Redi, IT (1668)

    • Redi’s experiments first to dispprove S.G.


Antonie van Leeuwenhoek

  • First to observe living microbes

  • his single-lens magnified up to 300X



Louis Pasteur

  • French chemist

  • Father/Founder of Modern Microbiology

  • Fermentation – a microbiological process

  • Beer/Wine not produced without microbes

  • Showed microbes caused fermentation & spoilage

  • Disproved spontaneous generation of m.o.

  • Developed aseptic techniques.

  • Developed a rabies vaccine.



Louis Pasteur 1822-95

  • Methods & Techniques of cultivation

  • Introduced sterilization

  • Tyndalization (Tyndal-1877)

  • Studied Silkworm disease, anthrax, chicken cholera, hydrophobia.

  • Introduced live vaccines – Jenner (Cow-pox vaccine)

  • Antirabic vaccine

  • Pasteur Institutes



Joseph Lister 1867

  • Prof of Surgery, Glasgow Royal Infirmatory

  • Introduced Antiseptic Surgery

  • Called Father of Antiseptic Surgery



Robert Koch

  • German general practitioner

  • Perfected bacteriological techniques

  • Isolated pure cultures of bacteria for the first time

  • Discovered Anthrax bacilli, Cholera vibrio, M. tuberculosis

  • Father of Medical Microbiology

  • Hypersensitivity

  • Established a sequence of experimental steps to show that a specific m.o. causes a particular disease.





Highlights in the History of Microbiology

  • 1887

  • Invented Petri Dish

  • (R.J. Petri)

  • 1892

  • Discovered viruses (Dmitri Iosifovich Ivanovski)

  • 1899

  • Recognized viral dependence on cells for reproduction (Martinus Beijerinck)



Highlights in the History of Microbiology

  • 1977

  • Developed a method to sequence DNA (W. Gilbert & F. Sanger)

  • 1983

  • Polymerase Chain Reaction invented (Kary Mullis)

  • 1995

  • First microbial genomic sequence published (H. influenzae) (TIGR)






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