GENETICS

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• GENETICS

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Central Dogma

• DNA transcribedgt RNA translatedgt proteins

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DNA structure
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The building blocks of DNA Nucleotides
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DNA Nucleotides include

• ADENINE base pairs with Thymine
• THYMINE base pairs with Adenine
• CYTOSINE base pairs with Guanine
• GUANINE base pairs with Cytosine

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DNA replication

• The duplication of DNA double helix prior to cell
  division
• Semiconservative

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DNA REPLICATION
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TYPES OF RNA

• Messenger RNA

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• Transfer RNA

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• Ribosomal RNA

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TRANSCRIPTION OVERVIEW
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TRANSLATION OVERVIEW
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POSTTRANSCRIPTIONAL PROCESSING
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DS DNA VIRUSES
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RETROVIRUSES
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REGULATION LAC OPERON
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MUTATIONS

• Mutations are heritable changes in DNA
• Types
• Beneficial
• Harmful (deleterious)
• Silent
• They can also be small (e.g., point) or large
  (e.g., deletions)

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• GENETIC EXCHANGE IN BACTERIA

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CONJUGATION
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TRANSFORMATION
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TRANSDUCTION
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PLASMIDS
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• INFECTION
• AND
• DISEASE

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TYPES OF DISEASES

• inherited or genetic
• congenital
• Degenerative
• due to nutritional deficiencies
• Endocrine
• Mental
• Immunological
• neoplastic (e.g,. cancer)
• iatrogenic (especially nosocomial)
• idiopathic (unknown cause).

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Inherited or genetic
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Congenital disease
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Degenerative diseases
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Nutritional deficiency
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(No Transcript)
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Mental
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Immunological

• In severe combined immunodeficiency, a person's
  ability to fight infections is severely impaired.
  This condition has been dubbed "bubble boy
  disease" and became widely known during the 1970s
  with the case of David Vetter, who lived for 12
  years sealed in a plastic, germfree environment.

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Cancer
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Iatrogenic (nosocomial)
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Idiopathic
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RELATIONSHIPS WITH MICROBES DEPEND ON

• Species of microbe
• Race
• Age
• Immune status
• Stress
• Nutrition
• Hygiene
• Etc.

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Types of relationships

• Beneficial to both
• Beneficial to one, harmful to the other -
• Pathogens
• Opportunists
• One benefits the other is not affected 0
• Harmful to both --

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• Seven challenges

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• RESERVOIRS
• Humans are the only reservoirs for many microbes
  (e.g., the organisms that cause pertussis,
  measles, colds, etc.). Some people appear to be
  healthy but they carry the microbes (carrier).
• Other microbes are maintained in non-human animal
  reservoirs (zoonosis).
• Finally some microbes are maintained in
  non-living environments (the soil for
  Clostridium).

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• NEW HOST
• Direct Contact can be between an infected person
  and a new host (person to person) or non-human
  animal to human, or from the environment
  (non-communicable infectious disease).
• Some pathogens are spread by the fecal-oral route
  that can be direct or indirect.
• Indirect modes of transmission are inanimate
  vehicles including fomites (an object that
  harbors pathogens because it is subject to
  constant contamination).
• Airborne transmission.

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ADHERENCE TO CELLS
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• INVASION OF DEEPER TISSUES

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• EVASION OF HOSTS DEFENSES

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• Multiplication or reproduction. This stage often
  results in the symptoms or damage (Table 19.1).
  For example, some microbes destroy cells.

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• Exiting the host
• The anatomical route is the portal of exit.

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Types and Courses of infectious disease include

• Acute diseases - rapid onset and rapidly run
  their course
• Chronic diseases - relative slow onset and last
  longer
• Subacute diseases - intermediate
• Local infections - confined to specific areas
• Systemic infections spread throughout the body.
• Subclinical or inapparent infections symptoms are
  slight
• Septicemia - bacteria are present in and
  multiplying in the blood
• Bacteremia occurs when bacteria are transported
  in the blood.
• Primary infection is the initial infection and
  can be followed by a secondary infection.

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Stages

• 1. Incubation period
• 2. Illness
• 3. Convalescence
• 4. Latent period
• 5. Recurrence

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Epidemiology

• the study of disease distributions in
  populations and of the factors that influence
  these distributions

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• DEFENSES AGAINST DISEASE

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OVERVIEW

• NON-SPECIFIC (INSIDE BODY IS SELF)
• 1ST LINE OF DEFENSE
• NON-SPECIFIC (SELF VS. NON-SELF)
• 2ND LINE OF DEFENSE
• SPECIFIC
• 3RD LINE OF DEFENSE

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• FIRST LINE OF DEFENSE
• Skin, mucus membranes, their products

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MECHICAL FACTORS INCLUDE

• 1. The closely packed cells and keratin of the
  epidermis (fig. 15.1)
• 2. The thick mucus produced by the cells of the
  mucous membranes
• 3. The lacrimal apparatus of the eye

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CHEMICAL FACTORS INCLUDE

• 1. sweat is high in salt and that inhibits many
  organisms.
• 2. Lysozyme degrades peptidoglycan and is found
  in tears, saliva, mucus, phagocytic cells, blood,
  and interstitial fluid.
• 3. Peroxidase in saliva, milk, body tissues, and
  phagocytes breaks down H2O2.
• 4. Lactoferrin bind iron and is found in saliva,
  mucus, milk, and some phagocytes
• 5. Defensins are thought to disrupt the
  integrity of the cell and are found in mucus
  membranes and phagocytes.

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• SECOND LINE OF DEFENSE

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PHAGOCYTOSIS
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inflammation
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Complement
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Interferons
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Lymphatic system
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Apoptosis
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• THIRD LINE OF DEFENSE

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• TYPES OF IMMUNITY

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Acquired immunity
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MHC
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Two types of specific immunity

• Antibody-mediated or humoral immunity
• Involves B cells (a type of lymphocyte)
• Cell-mediated immunity
• Involves T cells (another type of lymphocyte)

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Components of Humoral immunity

• Virgin B cells
• Plasma cells (those that produce antibodies)
• Memory cells
• Antibodies (aka Immunoglobulins)

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Structure of a typical antibody
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Types of Antibodies
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Cell-mediated immunity components

• Various types of T cells

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SPECIFIC IMMUNITY

• http//science.nhmccd.edu/biol/inflam.swf

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Antibody-mediated
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Macrophage/processed Antigen/T helper complex
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Clonal selection
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Relationship between two types of specific
immunity
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Cell-mediated immunity
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Primary and Secondary immunity
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Vaccinations

• Cell-free
• Live attenuated
• Killed, whole cell

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Immunopathologies

• Too much of an immune response
• E.g., allergic reactions, autoimmune diseases
• Too little of an immune response
• E.g., AIDS, DeGeorge syndrome, Severe
• Combined Immunodefiency