Good & Bad of Bacteria Flashcards
What bacteria causes botulism
Clostridium botulinum
Explain how Clostridium botulinum works?
Toxin binds to presynaptic stimulatory terminal - blocks the release of neurotransmitter acetylcholine (needed for muscle stimulation) - 18-36 hours for symptoms to begin- weakness, dizziness, dryness of mouth - flaccid paralysis e.g. difficulty swallowing, speaking, descending weakness in skeletal muscle
What bacteria causes tetanus
Clostridium tetani
Explain the toxin produced by Clostridium tetani?
Similiar structure to C. botulinum toxin - different target cells - static paralysis - tetanospasmin shows tropism for inhibitory motor neurons of the CNS
What bacteria causes Chloera?
Vibrio Cholerae
What is a cholera cot?
Plastic cot with a hole leading to a collection bucket - keeps patient, cot, & clinic clean
What science was established to determine the cause of cholera?
Epidemiology by John Snow in 1849 - traced the cause of an outbreak in Soho to one pump - water-born not air-born
What science was established to determine the cause of cholera?
Epidemiology by John Snow in 1849 - traced the cause of an outbreak in Soho to one pump - water-born not air-born
What is Epidemiology?
Study of the factors affecting the health & illness of a population - logic behind interventions for public health & preventive medicine - outbreak investigation, study design, data collection & analysis
What causes necrotising fascitis?
Group A Streptococci
Explain a Group A Streptococcus infection?
Exposed mucous membrane(skin lesions) - necrotising fascitis - skin must be removed and replaced by skin graft
What is a Biofilm?
Some bacteria produce an organic polymer matrix & become embedded in it - protects from being washed away or attacked by immune cells or antibiotics - catheter sites
What bacteria causes TB
Mycobacterium tuberculosis
Explain TB infection
Chronic bacterial infection - spread through air - usually affects lungs - 2 billion infected - 8 million develop it each year - 3 million die - affects people with weakened immune system (HIV, AIDS) - immune response causes damage - steroids to reduce inflammation
What are opportunistic pathogens?
Part of the normal microbiome that causes diseases when the immune system is compromised
What is the most common bacteria that causes tooth decay?
Streptococcus mutans
Name 2 opportunistic pathogens
Streptococcus mutans - tooth decay
Staphylococcus aureus - boils & abscess
How does S. mutans cause tooth decay?
High sugar diet - food - bacterial growth = plaque - metabolises sugars & excretes acid - wear down enamel
Explain S. aureus
Lives in nasal cavity of 30% population - cause serious infection (skin)
What virus causes COVID-19
SARS-CoV-2 (severe acute respiratory system coronavirus-2)
Explain the 2 types of decomposition
Autolysis - breakdown by body’s own chemicals & enzymes
Putrefaction - breakdown by bacteria
Occurs at the time of death - release gas & body swells
Name 2 bacteria that can be used as pesticides?
Bacillus thuringienesis - Gram positive, soil dwelling - produces BT toxin - Lepidopteran-specifc insecticide
Pseudomonas fluorescens - produces anti-fungal compound - protect sugar beet
What are the benefits of bacterial pesticides over chemical pesticides?
More specific, less harmful to environment, die off after food source is gone
What is bioremediation?
Processes using microorganisms, fungi, green plants, & enzymes to return the environment altered by contaminants to its original condition
2 specific examples of bacteria used in bioremediation
Deinococcus radiodurans - most radioresistant organism - consume & digest toluene & ionic mercury from radioactive nuclear waste
Pseudomonas putida - break down xylene & camphor
Use of bioremediation example
Cleaning chlorinated hydrocarbons from oil spils in soil & groundwater - nitrate & sulphate fertilisers added help indigenous or exogenous bacteria - can reach areas with excavation - cheaper than ex situ treatment e.g. incineration
Aerobic & anaerobic bacteria in sewage treatment - break down organic material to harmless soluble sludge in settling tanks - produce methane used for energy
What is biotechnology?
Application of bacteria, fungi, algae, etc. to manufacturing & services industey
What bacteria are used for fermentation?
Lactobacilli
Explain the differnece between heterofermentous & homofermentous lactobacilli?
Heterofermentous - lactic acid, ethanol, CO2
Homofermentous - lactic acid
Explain lactobacilli?
Gram + aerotolerant anaerobes - complex nutrition - uses sugar as a food source - L. delbrueckii & L. acidophilus (yogurt) - S. bovis produce polylactic acid - sauerkraut, pickles, some fermented meats
Explain normal flora/microbiota?
Internal tissue is m/o free (blood, brain, muscle) - surface tissue (skin & mucous membranes) colonised by 200 m/o species, mostly mutualistic, bacteria gain nutrients, stable environment, constant temperature, protection, stimulation of immune system, exclude potential pathogens
Explain some opportunistic pathogens?
Escherichia coli in colon usually synthesises Vitamin B - cause infection
Candida infections in vaginal tract (thrush)
What allows opportunistic pathogens to cause disease?
Antibiotic treatment, immunocompromised
Explain nitrogen’s role in biology?
Most abundant element in the atmosphere - vital element - amino acids, proteins, vitamins, & nucleic acid - primary nutrient of green plants (modified before being used by living systems)
Explain nitrogen fixation?
Molecular nitrogen reduced to form ammonia N2 > NH3 - 85% biological, 13% industrial - Rhizobium & Bradyrhizobium in agriculture
Explain the symbiotic relationship in
Mutually beneficial - legume plants (alfalfa, white clover) & rhizobia bacteria - gives nitrogen to plant as ammonium - legume provides carbohydrates to bacteria - increases soil fertility
