Identification Of The First Symbiotic Determinants Of Vibrio Fischeri, The Light Organ Symbiont Of Euprymna Scolopes. - Page 174 |
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161
matrix was necessary. The primary difficulty was the separation of the crypt matrix
from the surrounding host tissue. A hint at the possibility arose during one of the first
dissections of an adult E. scolopes by Drs. McFall-Ngai and Ruby (U.S.C.). While
preparing the dissected animal for photography, a cream colored, cohesive paste
streamed out of the light organ pores. Unfortunately, despite numerous subsequent
dissections of adults, this phenomena was not repeated again. Since the animals vent
naturally 90% of the symbiont population each dawn, I thought it was possible that the
expulsion of the crypt content could be induced in an anesthetized, dissected animal by
simulating the dawn light condition. This approach resulted in the release of a cream
colored paste streaming out of light organ pores. 1 was able to collect the symbiotic
bacteria and their surrounding matrix. This approach allowed me to examine the crypt
matrix, the fluid and material bathing the bacteria inside crypt, and the symbionts in their
symbiotic state with minimal contamination of host material. This approach may also
provide us with a view of how the symbionts are adapted to this special environment.
The second possible source of amino acids for the auxotrophs were free amino
acids secreted into the crypt matrix. A difficulty in measuring the amino acids was that if
amino acids were present in crypt matrix, it was likely that the bacteria are utilizing them
and subsequently the amino acids could not be detectable or only present at much lower,
steady state, concentration. This possibility warranted a more comparative approach.
One should consider the crypt matrix to be more like a fluid than the contents of a cell
and thus I compared the free amino acid composition of the crypt matrix to that of blood
and cerebral fluid of adult squid. In these fluids the total concentrations of free amino
acids was much lower (at least 100 fold) than in the animal tissues (Tables 3 and 4). In
the crypt matrix, arginine and lysine were present at a concentration of 5 |xM, while the
concentration of glycine was less than 2 pM (Table 3). These concentrations contrasted
dramatically to the observation that the glycine auxotroph colonized as well as the parent
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| Title | Identification Of The First Symbiotic Determinants Of Vibrio Fischeri, The Light Organ Symbiont Of Euprymna Scolopes. - Page 174 |
| Repository email | cisadmin@lib.usc.edu |
| Full text | 161 matrix was necessary. The primary difficulty was the separation of the crypt matrix from the surrounding host tissue. A hint at the possibility arose during one of the first dissections of an adult E. scolopes by Drs. McFall-Ngai and Ruby (U.S.C.). While preparing the dissected animal for photography, a cream colored, cohesive paste streamed out of the light organ pores. Unfortunately, despite numerous subsequent dissections of adults, this phenomena was not repeated again. Since the animals vent naturally 90% of the symbiont population each dawn, I thought it was possible that the expulsion of the crypt content could be induced in an anesthetized, dissected animal by simulating the dawn light condition. This approach resulted in the release of a cream colored paste streaming out of light organ pores. 1 was able to collect the symbiotic bacteria and their surrounding matrix. This approach allowed me to examine the crypt matrix, the fluid and material bathing the bacteria inside crypt, and the symbionts in their symbiotic state with minimal contamination of host material. This approach may also provide us with a view of how the symbionts are adapted to this special environment. The second possible source of amino acids for the auxotrophs were free amino acids secreted into the crypt matrix. A difficulty in measuring the amino acids was that if amino acids were present in crypt matrix, it was likely that the bacteria are utilizing them and subsequently the amino acids could not be detectable or only present at much lower, steady state, concentration. This possibility warranted a more comparative approach. One should consider the crypt matrix to be more like a fluid than the contents of a cell and thus I compared the free amino acid composition of the crypt matrix to that of blood and cerebral fluid of adult squid. In these fluids the total concentrations of free amino acids was much lower (at least 100 fold) than in the animal tissues (Tables 3 and 4). In the crypt matrix, arginine and lysine were present at a concentration of 5 |xM, while the concentration of glycine was less than 2 pM (Table 3). These concentrations contrasted dramatically to the observation that the glycine auxotroph colonized as well as the parent |
