Week 3

• What do Gram positive bacteria have that retains the purple color during staining?

  A thick layer of peptidoglycan
• What are the low GC gram-positive bacteria known as?

  The firmicutes
• What are the two categories of Gram positive bacteria based on spore formation?

  • Non-spore forming bacteria:
  • Lactic acid bacteria (e.g., Streptococcus, Lactobacillus)
  • Staphylococcus
  • Listeria
  • Mycoplasma
  • Spore forming bacteria:
  • Clostridium
  • Bacillus
• What are the high GC gram-positive bacteria called?

  Actinobacteria
• Name three genera of high GC gram-positive bacteria.

  • Streptomyces
  • Corynebacteria
  • Mycobacteria
• What is a distinctive feature of mycoplasmas?

  They lack a cell wall, giving them a unique shape and flexibility
• How is the plasma membrane of mycoplasmas strengthened?

  By the inclusion of sterols
• Why do mycoplasmas stain gram-negative despite being related to low GC gram-positive bacteria?

  Due to their plasma membrane composition
• What range of shapes do mycoplasmas exhibit?

  From small coccoid forms to larger elongated or branched structures
• Why are mycoplasmas sensitive to osmotic lysis?

  Because they lack a cell wall
• Which mycoplasma species are known to exhibit gliding motility?

  Mycoplasma pneumoniae and Mycoplasma genitalium
• What adaptations do mycoplasmas have for survival?

  • Inclusion of sterols in the plasma membrane for strength and stability
  • Sterols help avoid immune response
• What diseases can mycoplasmas cause?

  Pneumonia, urethritis, and arthritis
• What is the significance of mycoplasmas in biological research?

  They are used as model organisms due to their simple structure
• How do mycoplasmas obtain nutrients?

  They are parasites of eukaryotic cells, relying on the host for essential nutrients
• What are the nutritional requirements of mycoplasmas?

  They require vitamins, fatty acids, amino acids, purines, and pyrimidines
• What characteristic shape do mycoplasmas form on solid agar?

  'Fried egg' shaped colonies
• What is unique about the genomes of mycoplasmas?

  They possess the smallest known genomes of any self-replicating organism
• What is the guanine and cytosine content in mycoplasma genomes?

  It ranges from 25-35%, which is lower than in other bacteria
• Why have mycoplasmas evolved small genomes?

  They have likely lost unnecessary genes due to their host-dependent lifestyle
• What are the implications of having small genomes for mycoplasmas?

  Reduced genetic diversity and vulnerability to environmental stresses
• What are the characteristics of Mycoplasmas and Ureaplasma?

  • Mycoplasmas:
  • Require cholesterol
  • Parasites of animal mucous membranes
  • Facultative anaerobes
  • Over 60 species recognized
  • Ureaplasma:
  • Microaerophilic
  • Require cholesterol and urea for growth
  • Associated with non-gonococcal urethritis
• What is the primary cause of primary atypical pneumonia (PAP)?

  Mycoplasma pneumoniae
• What age group is primarily affected by Mycoplasma pneumoniae infections?

  Individuals aged 5-20 years old
• How is Mycoplasma pneumoniae transmitted?

  Through close personal contact via respiratory droplets
• What are the symptoms of Mycoplasma pneumoniae infection?

  Symptoms range from mild flu-like illness to severe pneumonia
• What role do polar tip organelles play in Mycoplasma pneumoniae?

  They facilitate specific adhesion to respiratory epithelial cells
• What does Mycoplasma pneumoniae produce that contributes to its pathogenicity?

  Hydrogen peroxide
• What diagnostic methods are used for Mycoplasma pneumoniae infections?

  PCR is the preferred method due to its sensitivity and specificity
• What antibiotics are effective against Mycoplasma pneumoniae?

  Erythromycin, doxycycline, azithromycin, and levofloxacin
• What are the three types of genital mycoplasmas?

  • Mycoplasma genitalium
  • Mycoplasma hominis
  • Ureaplasma urealyticum
• What percentage of normal adults have antibodies to genital mycoplasmas?

  50%
• What conditions can genital mycoplasmas cause?

  Non-gonococcal urethritis, cervicitis, and endometritis
• How can genital mycoplasmas be transmitted?

  From mother to fetus
• What is the preferred method for detecting genital mycoplasmas?

  Molecular techniques like PCR
• What is the treatment for genital mycoplasmas?

  Doxycycline pretreatment followed by azithromycin or moxifloxacin
• What do lactic acid bacteria produce as a product of fermentation?

  Lactic acid
• What are the characteristics of lactic acid bacteria?

  They are non-spore forming, non-motile, and aerotolerant anaerobes
• How do lactic acid bacteria obtain energy?

  Through substrate level phosphorylation, relying on sugar
• What do lactic acid bacteria require for growth?

  Vitamins, amino acids, purines, and pyrimidines