Intro to Micro Notes

Microbiology: The study of organisms too small to be seen without magnification (micro-small; bios-life)

Microbiology integrates several diverse specialized disciplines –virology, parasitology, mycology, bacteriology

Microbiologist study genetics, physiology, characteristics, interactions with environment (including humans)

 

Microorganisms: microscopic (small) organisms, also referred to as “microbes”

 

              Microbes are found in all natural habitats: “ubiquitous” =everywhere

              Water, soil, animals, plants, rocks, and air.

Billions of microbes are even on/in our body: human microbiome

 

Microorganisms include: Bacteria, Viruses, Fungi, Protozoa, algae , Helminths (worms --not    technically because of large size)

 

TYPES

•       Acellular : prion and virus

•       Cellular: bacteria, archaeon, fungi & protozoa

 

Medical microbiology is applied to medicine

•        a branch of medical science concerned with the prevention, diagnosis and treatment of infectious diseases.

•        In addition, this field of science studies various clinical applications of microbes for the improvement of health—”Preventative Medicine”

 

PATHOLOGY- STUDY OF DISEASE (or suffering)

•       Includes structural and functional changes associated with disease

 

 

MICROBIAL STRUCTURE:

 Two cell types:

Prokaryote (pro=before; karyo=nucleus) – all are microscopic, unicellular organisms, lack nuclei and membrane-bound organelles

                             bacteria and archaea (aar-kee-uh)

Eukaryote (Eu=true) – can be unicellular (microscopic) or multicellular, have nucleus and membrane-bound organelles

Algae, protozoa, molds and yeast (microscopic) and certain worms and arthropods (not all stages are microscopic)

 

                                                           Infectious particles-acellular

•       Viruses - acellular, parasitic particles composed only of a nucleic acid (DNA or RNA) and protein

–       Obligate intracellular parasites that can only divide/exists if it invades a host cell (plant, bacteria, animal)—smaller than bacteria

•       Prions (“pree-aan”) “proteinaceous infectious particles”

–       Consists of only proteins

–       Simpler than viruses

 

MICROBES IN ENERGY & NUTRIENT FLOW

 

Photosynthesis: Light fueled conversion of carbon dioxide to organic material

•       Photosynthetic microbes (including algae) account for over 50% of earth’s photosynthesis

•       Contributes to the majority of the oxygen in the atmosphere

Decomposition: Breakdown of dead matter and wastes into simple compounds

•       Compounds return to the natural cycles of living things.

•       Responsible for the content of soil, water and atmosphere (temperature)

HUMAN USE OF MICROORGANISMS

 

•       Biotechnology: Production of foods, drugs, and vaccines using living organisms

–       Manipulating microbes to make products

•       Genetic engineering: Manipulating the genes of organisms to make new products –used to make vaccines-recombinant DNA

•       Bioremediation: Using living organisms to remedy an environmental problem (i.e. oil spill)

 

LIFESTYLES OF MICROORGANISMS

 

•       Majority live a free existence, are relatively harmless and often beneficial

•       Some microorganisms have close associations with other organisms

–       Parasites live on or in the body of another organism called the host and causes damage to the host.

–       Pathogen damages host through infection and causing disease

 

Human Microbiome consists of 10-100 trillion microbes harbored by a person.

•              Most areas of the body in contact with the outside environment harbor resident microbes (see table below)

•       Internal organs, tissues, and fluids are microbe-free

•       Transients – microbes that occupy the body for only short periods

•       Residents – microbes that become established

•       Normal flora  are essential to the health of humans

•       Normal flora create an environment that may prevent infections and can enhance host defenses

•       Antibiotics, dietary changes, and disease may alter flora

•       This can result in colonization of pathogens

                       Probiotics – introducing known microbes back into the body

 

HISTORICAL FOUNDATIONS OF MICROBIOLOGY

 

•       Spontaneous Generation - an early belief that some forms of life could arise from vital forces present in nonliving or decomposing matter (flies from manure, etc.) –”Abiogenesis”

•       The belief of life from nonliving matter was introduced by Aristotle.

•         Louis Pasteur eventually disproved spontaneous generation and proved the Theory of Biogenesis - the idea that living things can only arise from other living things

•       Swan-neck flask experiment 1861

•       Antonie van Leeuwenhoek (1632-1723

                             Dutch linen merchant

•       First to observe living microbes

•       Developed a single-lens “microscope” that magnified up to 300X

 

SCIENTIFIC METHOD

 

•       Approach taken by scientists to explain a certain natural phenomenon

•       Form a hypothesis - a tentative explanation that can be supported or refuted

–       Deductive approach “If…, then….”

•       A lengthy process of experimentation, analysis, and testing either supports or refutes the hypothesis

•       Results must be published and repeated by other investigators.

•       If hypothesis is supported by a growing body of evidence and survives rigorous scrutiny, it moves to the next level of confidence - it becomes a Theory.

•       A theory is a viable explanation that has yet to be disproved

•       If evidence of a theory is so compelling that the next level of confidence is reached, it becomes a Law.

 

ASEPTIC TECHNIQUE

             The human body is a source of infection:

–       Dr. Oliver Wendell Holmes (1843 - US) – observed that mothers of home births had fewer infections than those who gave birth in hospitals

–       Dr. Ignaz Semmelweis (1850 - Austria) – correlated infections with physicians coming directly from the autopsy room to the maternity ward

•       Importance of hand washing

–       Joseph Lister (1867 - Scotland) – introduced aseptic techniques to reduce microbes in medical settings and prevent wound infections

•       Involved disinfection of hands using chemicals prior to surgery

•       Use of heat for sterilization

 

Terms

•       Aseptic (no infection) technique= methods of handling patient specimens or other sources of microbes in a way that prevents infection of the handler and others who may be exposed

•       Asepsis= a condition free of viable pathogenic microorganisms

•       Sterile= completely free of all microbial life forms, including spores and viruses

•       Sterilization= any process that completely removes or destroys all viable microorganisms, including viruses, from an object or habitat.

 

THE GERM THEORY OF DISEASE

 

•       Germ Theory states that diseases are caused by the growth of microbes in the body and not by sins, bad character, poverty, etc.

•       Two major contributors: Louis Pasteur and Robert Koch

Louis Pasteur

•       Showed that microbes caused fermentation and spoilage

•       Disproved spontaneous generation of microorganisms (Swan Neck Experiment)

•       Developed pasteurization

•       Heat treat followed by rapid chilling of perishables

•       Demonstrated what is now known as Germ Theory of Disease

Robert Koch

•       Established Koch’s postulates

•       a sequence of experimental steps that verified the germ theory

•       Identified cause of anthrax, tuberculosis, and cholera

•       Developed pure culture methods

 


•                     Macromolecules: Carbohydrates, Proteins, lipids and nucleic acids

 

CARBOHYDRATES

              provide energy to cells and structural support

•       water-soluble

•       contain C, H, and O

•       ratio of H to O close to 2:1 (C6H12O6

monosaccharide's – glucose, fructose

disaccharides – sucrose, lactose and maltose

                      Polysaccharides-made of thousands of glucose molecules

                      starches are plant products

                      Cellulose-fiber portion of plant cells and microscopic algae

                Agar- from seaweed, used for growing bacteria

 

   LIPIDS

 

soluble in organic solvents; insoluble in water

•       fats (triglycerides)

•        used primarily for energy

•        building blocks are 1 glycerol and 3 fatty acids per molecule

•       phospholipids

•        major component of cell membranes in animal cells and type of bacterium--mycoplasms

PROTEINS

  • predominate organic molecule

  • -amino acids are the subunits of proteins; 20 amino acids make up human proteins. Peptide bonds join amino acids to one another

  • -a protein consists of from 50 to thousands of amino acids in a specific sequence.

  • building blocks are amino acids

  • Peptide: short chain of amino acids

  • 3 dimensional structure important for function

    • Enzymes: catalysts for all chemical reactions

    • Antibodies

    • Denature: loss of normal structure/nonfunctional

      • Heat, acid, alcohol, disinfectants

NUCLEIC ACIDS

  • made up of nucleotides

  • nucleotide consists of pentose sugar, a phosphate group, and a nitrogenous base.


    DNA is a double strand of nucleotide.

              makes up the chromosomes of cells and is the genetic code for the synthesis of proteins.

  • RNA is a single strand of nucleotides.

    • (messenger)MRNA: functions in protein synthesis by copying gene

    • Transfer (t)RNA: carrier for amino acid in protein synthesis

    • Ribosomal (r) RNA : component of ribosome

  • ATP=adenosine triphosphate; is a nucleotide that is specialized to trap and release energy.

    • -When cells need energy, ATP is broken down to ADP (adenosine diphosphate) + P, and the energy is released for cell processes

 

TAXONOMY: Organizing, Classifying and Naming Microorganisms

•       Formal system originated by Carl von Linné (1701-1778)

•       Concerned with:

–       Classification – orderly arrangement of organisms into groups

–       Nomenclature – assigning names

–       Identification – discovering and recording traits of organisms for placement into taxonomic schemes

Hierarchy-descending ranks

•       Domains - Archaea, Bacteria & Eukarya (3)

•       Kingdom

•       Phylum or Division

•       Class

•       Order

•       Family

•       Genus

•       Species

 

Naming microorganisms

•       Binomial (scientific) nomenclature

•       Both italicized or underlined

•       Staphylococcus aureus (S. aureus)

•       Bacillus subtilis (B. subtilis)

•       Escherichia coli (E. coli)

  Genus – always capitalized

  species – lowercase


–       Names are from:  discoverer or notable microbiologist, Characteristics-shape/ color, Location where it was found, OR Disease or symptom