Improvements in the sensitivity and reproducibility of nephelometric endotoxin determinations using endotoxin-activated enzyme from Limulus amebocyte lysate are achieved by contacting endotoxin-coagulated lysate with an ionic surface active suspending agent, generally a mixture of detergent and suspending agent. Instrumentation improvements further enhance results.
A process for measuring the amount of endotoxin or (1.fwdarw.3)-.beta.-D-glucan (referred to hereinafter as .beta.-glucan) contained in a sample, which comprises mixing the sample with amebocyte lysate of horseshoe crabs in the presence of at least one water-soluble polymer selected from the group consisting of a polyethylene glycol, a polyvinyl alcohol, a methyl cellulose and a hydroxypropyl cellulose, applying a light to the resulting mixture, measuring the time required until a degree of optical variation of the resulting mixture reaches a predetermined value after the mixing of the sample with the amebocyte lysate, or after the lapse of the predetermined time from the mixing of the sample with the amebocyte lysate, and determining the amount of endotoxin or .beta.-glucan contained in the sample on the basis of the relationship between the said time and the amount of endotoxin or .beta.-glucan; and also a reagent for measuring the amount of endotoxin or .beta.-glucan contained in a sample, which comprises amebocyte lysate of horseshoe crabs and at least one water-soluble polymer selected from the group consisting of a polyethylene glycol, a polyvinyl alcohol, a methyl cellulose and a hydroxypropyl cellulose.
A pretreating method for a sample such as plasma for endotoxin measurement which includes diluting the sample with a surfactant-containing aqueous solution, and subjecting the diluted sample to heat treatment can prevent influences of inhibitors, etc. present in the sample and gives high recovery of endotoxins.
The present invention relates to an artificial bait for marine animals, comprising cell-free hemolymph of a horseshoe crab. The cell-free hemolymph of the horseshoe crab, which is the byproduct from the manufacture of Limulus Amebocyte Lysate (LAL), is an excellent attractant to be used in artificial baits for marine animals. The baits according to the invention attract the target marine animals better than the horseshoe crab itself. Further, the baits of the invention seem to attract non-target game less than the target game. The present invention also relates to a method of preparing a bait comprising cell-free hemolymph of a horseshoe crab, and a method of attracting marine animals.
In the culturing of micro-organisms, non-microbial turbidity in the supernate is prevented by including an adsorbant for components which cause such non-microbial turbidity; e.g., lipoproteins and/or chylomicrons, with such adsorbant being soluble in the culture media. The adsorbant sediments such components, and is particularly effective in culture media which include an anticoagulant. Carboxy Methyl Cellulose is a particularly effective adsorbant.
The invention provides methods and compositions for the detection and/or quantification of bacterial endotoxins. In particular, provided herein is an inexpensive and reproducible method for producing an improved amebocyte lysate preparation having reduced Factor G activity. Provided also is an endotoxin-specific amebocyte lysate preparation produced by such a method. In addition, the invention provides methods and compositions for enhancing the sensitivity to endotoxins of amebocyte lysate preparations having reducing Factor G activity. In particular, the sensitivity of such amebocyte lysate preparations to endotoxins can be enhanced by the addition of exogenous (1.fwdarw.3) .beta.-D-glucan.
