MIDTERM 2 EndoSpores Flashcards
What can contribute stress towards bacteria?
- Changes in Temperature
- Fluctuating Levels of Nutrients
- Increasing/Decreasing pH
- Threat of Inundation(excess amount/Flood) with water
- Desiccation(Drying to extreme) in absence of water
What is the form of survival bacterias can use to deal with these stresses?
They Form Endospores.
True or False: Endospores can be made by any genera. If false, what is this strategy limited to?
False, The endospore Strategy is limited to Gram-Positive Rods
What are the 2 most common spore formers?
- Bacillus
2. Clostridium
What spherical shaped cell can form spores? and What Genus number is it in?
Sporosarcina, Genus V
How can you describe endospores?
it may be described as minimal, compact, highly-resistant, and metabolically inactive version of bacterial cell
What happens first in the process of making endospores?
Cells Begin to replicate and seperate the DNA and some of the cytoplasmic contents in one part of the parent cell
What is the spore coat and how is it formed?
The many layers thats tough and resistant that covers the endospore. It forms through a complex process of signaling involving both the mother cell and the developing spore.
What is an Endospore?
a portion of a mother cell that turns into a compact, highly dessicated body
What is the Sporangium?
The mother cell that holds the endospore inside. (the space around the endospore)
What are vegetative cells?
Cells without spores.
Can you tell the difference between vegetative cells and sporangia? If you cant, Why?
You cant tell a difference because vegetative cells have the inherent capacity to make spores under the bacterial strains.
Why are they called Endospores?
because theyre spores that are formed inside the cell.
What happens after completion of spore formation?
- Sporangium may remain attached to the spore
2. Or die and lyse releasing the spore
What is a free spore?
spore not associated with sporangium.
Where can the spores be located in the sporangium?
- Centrally
- Terminally at the ends
- Subterminally(almost at the end of the cell)
What can be the shape of the spore inside the sporangium?
- Oval
2. Spherical
Why is it important to know the location and shape of spores?
They are characteristics of different sporulating strains and serve as important diagnostic features
True or False: Sporulating strains may exhibit spore formation under all growth conditions
False
True or False: The absence of spores rules out spore-forming ability. If false, explain why.
False, The absence of spores does not rule out spore-forming ability as the cells might simply be in the wrong growth stage or in the wrong growth medium.
Which log phase is likely for spore formation to fall under?
The stationary phase of growth. it requires specific nutrients to make spores.
Which medium is best to successfully induce the production of spores?
The Nutriet Sporulation Medium ( NSM )
How does NSM work?
Cells will grow rapidly, and quickly reach the stationary phase, and then experience nutrient limitation.
What does NSM contain? and why is it important?
it contains Mn2+ which is necessary for the process of sporulation in many spore formers.
What are qualities of endospores? and what makes them a problem?
They are resistant to a significant number of strains allowing them to be simultaneously easy to store and extremely difficult to eliminate
What three features help explain the resistant properties of spores?
- A mature spore may have less than 1/3 as much as water as vegetative cells, making it DESSICATED to the point of being almost crystalline by nature
- Because theres an absence of water, theres very little to none METABOLIC ACTIVITY.
- a THICK SPORE COAT containing large amounts of calcium dipicolinate and many layers of peptidoglycan protects the spore
How does the thick spore coat add to the resistant properties of spores?
They prevent the penetration of chemicals including water, thus maintaining the protection against agents that interfere with cellular processes.
How does the lack of metabolic activity add to the resistant properties of spores?
It reduces or eliminates the effectiveness of chemicals such as antibiotics that kills cells by targeting specific metabolic processes
How does the extreme desiccation of spore add to the resistant properties of the spore?
it protects it from all activities that involve water including freezing, desiccation, and ionizing radiation.
Whats the best way to kill a spore?
- Use a combination of elimination methods (steam, heat and high pressure in autoclaving)
- Germinate the spores and kill the resulting vegetative cells
Where do most spore-forming bacteria produce toxins?
They produce toxins during vegetative growth
What bacteria is an exception for producing toxins at a different stage?
Bacillus Thuringiensis produces bt toxins at the same time as sporulation so that the spore and toxin crystal are both seen in the sporangium.
So why do we give a shit about spore forming bacteria?
they are known to cause serious illness in humans
What does C.botulinum cause?
Causes botulism through food or through infection of wounds
What does C.Perfringens cause?
Causes food poisoning and gangrene
What does C.Tetani cause?
Tetanus
What does C.Difficile cause?
Causes a GI tract condition known as pseudomembranous colitis
What does B.anthracis cause?
Anthrax
What does B.cereus cause?
Food poisoning with vomiting and diarrhea
How is toxin produced in most cases of clostridium infection?
the toxin is produced by vegetative cells growing under conditions that favor the obligately anaerobic clostridium
How else can toxins be produced in cases of clostridium infections? What type of toxins are they?
Spores may also germinate and produce toxins during vegetative growth. These toxins are neurotoxins.
What is significance of botulinum toxin?
its harnessed for cosmetic purposes to reduce facial wrinkles, under common name of botox
How else can toxins be exploited for commercial purposes? and what bacteria is used?
Bacillus Thuringiensis endospores are formed in the guts of insects and are naturally found on plants. B. Thuringiensis produces a crystal protein at the same time as sporulation and that crystal is a toxin that kills the host insects. Upon sporulation, the bacterial cell lyses and the toxins are released. These bacteria are currently being mass produced and used as bioinsecticides that are harmless to humans
Why do endospores shine bright under the microscope?
The extreme dessication of the mature endospores means that it is also a very dense body and quite impermeable to light. The refractile nature of the endospore makes them look very bright under the microscope
What form of microscopy do we use to observe endospores?
Phase contrast
How else can we observe Endospores?
- Simple stains
2. Gram Stains
How does simple stain/gram stain work when you observe endospores?
- The stain penetrates the sporangium but not the spore so that the resulting stained smear has colored vegetative cells and sporangia with bright, unstained spores seen either in the sporangia or as free spores
What is the significance of a gram stain even though its similar to the simple stain when observing endospores?
The breakdown of sporangium after formation of the mature spores may introduce variability in the staining results. If this occurs, it is best to repeat the gram-stain with a younger culture with fewer actively sporulating cells.
Information about hot malachite green dye for observing endospores?
this dye can be forced into the spore using heat in the form of steam at 100 degrees celcius.
What is Malchite green dye?
its a weak basic dye that readily enters and leaves bacterial cells.
