Methods for the detection and/or quantification of gram positive bacterial contaminants
The invention provides methods and compositions for the detection and/or quantification of a Gram positive bacterial contaminant in a sample. In particular, the invention provides hemocyte-based preparations, methods of making such hemocyte-based preparations, and methods of using such hemocyte-based preparations for the detection and/or quantification of the Gram positive bacterial contaminant.
1. A method of producing a preparation for detecting the presence and/or quantity of lipoteichoic acid in a sample, the method comprising the steps of:
(a) providing a crustacean hemocyte preparation, wherein the crustacean hemocytes in the preparation (i) have an outer membrane and (ii) contain lipoteichoic acid reactive material disposed therein;
(b) rendering the outer membrane of at least a portion of the crustacean hemocytes in the crustacean hemocyte preparation permeable to the lipoteichoic acid reactive material so that the lipoteichoic acid reactive material is released from the crustacean hemocytes;
(c) harvesting the lipoteichoic acid reactive material released from the crustacean hemocytes; and
(d) determining that the lipoteichoic acid reactive material harvested in step (c) is activatable by lipoteichoic acid such that prophenol oxidase is converted into phenol oxidase when the lipoteichoic acid reactive material is contacted with lipoteichoic acid.
2. The method of claim 1 , wherein in step (b), the outer membrane is rendered selectively permeable by exposure to a membrane permeabilizing agent.
3. The method of claim 2 , wherein the permeabilizing agent is an ionophore.
4. The method of claim 3 , wherein the ionophore is a calcium ionophore.
5. The method of claim 1 , wherein the crustacean is selected from the group consisting of Cancer borealis, Cancer irroratus, Carcinus maenas, Hemigrapsus sanguineus , and Limulus polyphemus.
6. The method of claim 1 , wherein the crustacean Cancer genus.
7. The method of claim 3 , wherein the ionophore is admixed with the crustacean hemocyte preparation to give a final concentration in the range from about 0.1 μM to about 100 μM.
8. The method of claim 7 , wherein the ionophore is admixed with the crustacean hemocyte preparation to give a final concentration in the range from about 1 μM to about 10 μM.