Thomas Gates Presentation

Confocal Microscopy of the Light Organ crypts in Juvenile Euprymna scolopes Reveals Their Morphological Complexity and Dynamic Function in Symbiosis
Thomas Gates-

Euprymna scolopes- in the crypts of the organs of this organism there is a symbiotic relationship.

Materials and Methods-
-Adult squid were gathered and mated once a week; eggs hatched put in 23 C water.
Removed from water and put in Vibrio fischeri free water. Some squid inoculated with Vibrio fischeri.

Vibrio fischeri was diluted, squid were placed in on scintillation vials

CRYPT Morphology
1. All crypts contain same four morphological regions
2. DT1 is shortest and has largest cross sectional area, DT3 is the smallest cross section and the longest.
3 Antechamber is medial to the duct
4. The bottleneck connects the antechamber and the deep crypt
5. Deep crypt is farthest from the pore and is the largest portion of the crypt

Localization of Vibrio fischeri
-Colonization has a very high success rate but many aspects vary
-Bacteria entered as early as 2h and first entered antechamber, bottle neck
-17 h many light organs were colonized
-By 24h the hosts diel expulsion starts taking over. About 10-40 minutes after the expulsion, there are less Vibrio fischeri in deep crypt and more towards bottleneck and antechamber. Deep crypt 3 actually expels the least amount, where deep crypt one expels the most.

Symbiont-induced Changes
-Decided to further study the morphologic changes of the deep crypts
-Concluded that in early stage of symbiosis DC regions can respond differently due to maturity.

Deep crypts 2 and 3
-DC2,3 have four morphologic changes
-DC2 is usually one stage ahead of DC3
-As long as DC3 isnt in stage 1, it will be able to hold Vibrio fischeri. DC2 always has the ability for Vibrio fischeri.

Crypt function
-Antechamber-produced NO2-, with cilia, this produces a chemical and physical barrier to other microbes and is selective of Vibrio fischeri.
-Bottleneck serves as a physical barrier to microbes but little study has been done
-Juvenile crypt development- All crypts vary in size and function,

Role of symbionts
-Unexpected results- incomplete venting from DC2 and DC3, failure to induce morphological conformation of DC2 and DC3
-Diel venting believed to be for regrowth of fresh V. fischeri.

Questions-
Ink sac acts as the iris which will let more or less light in to reduce the amount of shadow casted to other predators.
Confocal-way of taking pictures that is more 3-D
They expel bacteria everyday to be more metabolically robust and allow very strong bacteria to shine more brightly
Knowing this is a squid and invertebrate- (Vibrio fischeri- gram -) can its immune system tell the difference btwn V. fischeri and V. cholera? Evidence shows it does discriminate even though we know right now that we don’t really know.

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