Biotechnology and Disease: A Deep Dive

Posted on Dec 3, 2024 in Biology

Biotechnology

Definition:

  1. A branch of knowledge developed since the discovery of DNA and its gene sequence.
  2. Enables procedures for changing an organism’s genetic constitution.
  3. Used in industrial processes to improve efficiency and productivity for human benefit.
  4. Applied to generate transgenic organisms, but the impact on human health and the environment is still being studied.

Transgenic Organisms

Definition:

  1. Living things with altered genetic compositions.
  2. Created to improve productivity, develop resistance to pathogens (viruses, bacteria), and climatic factors (drought, temperature changes, etc.).
  3. Obtained using bacterial restriction enzymes that recognize short DNA sequences, allowing multiplication and incorporation into the target organism.
  4. Achievable through recombinant DNA technology.
  5. Potential effects on biodiversity and humans are still being researched.

Methods of Obtaining Transgenic Organisms (Artificial)

  1. Shells: Solid material carrying a foreign gene copy is shot into cells.
  2. Injection: DNA is injected into the cell using needles.
  3. Dissemination: Genes cross the cell membrane to reach the nucleus.
  4. Viruses: Inject their DNA (adenovirus) or RNA (retroviruses) into the cell. These are obligate parasites with metabolic activity only within a cell.

Defense System

  1. Harmonic health is altered by pathogenic microorganisms (bacteria, fungi, protozoa) and pathogens (viruses).
  2. Toxins (poisons) are produced and must be removed by the defensive system (white blood cells).
  3. Natural or innate immunity provides resistance to pathogenic organisms. This immunity is present at birth and reinforced by colostrum.
  4. Acquired immunity artificially reinforces the immune system.
  5. Vaccines containing attenuated pathogens stimulate the body to develop antitoxins (antibodies).
  6. Passive immunity: The host receives pre-produced antibodies.

Disease Classification (WHO)

  1. Infectious: Transmitted from a diseased organism to a healthy one. Stages: incubation, development (symptoms), and convalescence. Examples: AIDS, leprosy, syphilis, influenza.
  2. STIs: Transmitted through intimate contact. Examples: AIDS, gonorrhea, condyloma, herpes.
  3. Hereditary: Transmitted through generations. Examples: blindness, Down syndrome, Turner syndrome, Klinefelter syndrome.
  4. Mental: Hereditary or traumatic. Examples: Alzheimer’s, epilepsy, bulimia.
  5. Metabolic: Alterations in chemical reactions. Examples: diabetes, cretinism.
  6. Traumatic: Caused by blows or bruises. Examples: sprains, fractures.
  7. Degenerative: Tissue alterations. Examples: leprosy, tumors, cancer, Parkinson’s.
  8. Social: Caused by external factors (e.g., alcohol, drugs, smoking). Can cause addiction.
  9. Nutritional: Food intake alterations. Examples: obesity, rickets, anorexia.
  10. Parasitic: Presence of parasites. Examples: lice, crabs, worms.

Pathogens

  1. Single-celled organisms.
  2. Produce toxins.
  3. Disrupt homeostasis, causing infectious diseases.
  4. Examples: bacteria, fungi, protozoa, viruses (macromolecules, obligate parasites).
  5. Transmitted through direct or indirect contact.
  6. Indirect transmission: Reservoirs (water, air, soil) or contaminated objects.

Bacteria

  1. Primitive organisms (e.g., cyanobacteria).
  2. Composed of prokaryotic cells (circular DNA, lacks histone, karyotheca, and organelles).
  3. Not all are pathogenic; some are beneficial.

Structure

  1. Capsule: Cell adhesion and protection.
  2. Cell wall: Bacterial shape.
  3. Flagella: Mobility.
  4. Pili: Bacterial conjugation (DNA transfer).
  5. Chromosome: Hereditary information.
  6. Ribosome: Protein synthesis.
  7. Fimbria: Attachment to host and genetic material exchange.
  8. Mesosome: Increased membrane surface, aids metabolism and cell division.
  9. Lamella:
  10. Plasmid: Metabolism.
  11. Cell membrane: Delineates bacteria, regulates substance passage, forms mesosome.

Bacterial Growth

  1. Adaptation: Metabolism adapts to environmental conditions.
  2. Exponential growth: Maximum growth rate, minimum generation time.
  3. Stationary phase: Accumulation and release of metabolites. Growth slows due to nutrient limitations.
  4. Death phase: Decreased bacterial count.

Bacterial Reproduction

Binary fission: DNA replication splits into two, separating DNA strands.

Plasmidal conjugation: Plasmid strand opens and moves to another bacteria via pili.

Chromosomal conjugation: Chromosomal DNA strand opens, integrates with plasmid DNA, and one strand moves to another bacteria.

Teichoic acid: Supports Gram-positive cell walls.

Peptidoglycan: Basic cell wall structure.

Bacterial Classification

Shape

a) Spherical (coccus): isolated, diplococcus, sarcina (4), streptococcus (chain), staphylococcus (cluster)

b) Elongated (bacillus): isolated (with or without flagella), chain

c) Spiral (spirilla, vibrios, or rod-shaped)

Staining (Gram Stain)

Gram-positive (+): Stains due to peptidoglycan and teichoic acid.

Gram-negative (-): Does not stain due to peptidoglycan, lipoproteins, and lipopolysaccharides.

Metabolism

Anaerobic respiration or fermentation (2-4 ATP molecules).

Fermentation produces lactic acid or alcohol.

Pasteurization kills bacteria.

Heterotrophic bacteria: Decompose substances or parasitize.

Autotrophic bacteria: Produce their own food (chemotrophic or photosynthetic).

Utility

Strengths:

  1. Intestinal flora, vitamin K and B synthesis.
  2. Food production (yogurt, cheese, alcohol).
  3. Transgenic organism generation.
  4. Decomposition.
  5. Nitrogen fixation.
  6. Copper leaching.
  7. Symbiotic relationships (e.g., rhizobium in legumes).

Weaknesses:

  1. Pathogenic potential.
  2. Food spoilage.
  3. Unpleasant odors.
  4. Water pollution.
  5. Eutrophication.
  6. Material fatigue.

Pathogenic Bacteria

  1. Cause diseases in plants, animals, and humans.
  2. Frequently affect skin, respiratory, digestive, genitourinary, and central nervous systems.
  3. Transmitted through direct or indirect contact.
  4. Controlled with antibiotics.

Antibiotic Effect

  1. Inhibits bacterial growth.
  2. Weakens cell wall.
  3. Inhibits protein synthesis and toxin production.
  4. Inhibits DNA synthesis.
  5. Bactericidal action.
  6. Inhibits cell wall components.

Bacterial Aggressiveness

  1. Invasiveness (Gram-negative bacteria).
  2. Host susceptibility.
  3. Hygienic conditions.
  4. Chemical bonds (endotoxins and exotoxins).

Bacterial Diseases

  1. Impetigo (skin, streptococcus)
  2. Abscess (skin, staphylococcus)
  3. Scarlet fever (skin, streptococcus)
  4. Necrotizing fasciitis (skin, streptococcus)
  5. Diphtheria (respiratory, Corynebacterium diphtheriae)
  6. Pertussis (respiratory, Bordetella pertussis)
  7. Pneumonia (respiratory, streptococcus)
  8. Tuberculosis (respiratory, Mycobacterium tuberculosis)
  9. Typhoid fever (digestive, Salmonella typhi)
  10. Gastroenteritis (digestive, Enterobacteriaceae)
  11. Cholera (digestive, Vibrio cholerae)
  12. Salmonellosis (digestive, Salmonella spp.)
  13. Diarrhea (digestive, Escherichia coli)
  14. Dental caries (digestive, bacterial plaque)
  15. Urinary tract infection (genitourinary, E. coli, Klebsiella)
  16. Gonorrhea (genitourinary, Neisseria gonorrhoeae)
  17. Syphilis (genitourinary, Treponema pallidum)
  18. Meningitis (CNS, Neisseria meningitidis)
  19. Paratyphoid fever (Salmonella paratyphi)
  20. Food poisoning
  21. Leprosy (Mycobacterium leprae)
  22. Tetanus (Clostridium tetani)
  23. Botulism (Clostridium botulinum)