In limulus amebocyte lysate test?

Asked by: Marlon Green
Score: 4.8/5 (43 votes)

The limulus amoebocyte lysate (LAL) test is a simple method for the detection of viable and non-viable Gram-negative bacteria. Certain cell-wall lipopolysaccharides (i.e. endotoxins) of this bacterial group lead to gelation of blood cell (amoebocytes) lysates of the Limulus polyphemus crab.

View full answer

Likewise, What does the term Limulus in the LAL test signify?

Limulus amebocyte lysate (LAL) is an aqueous extract of blood cells (amoebocytes) from the Atlantic horseshoe crab Limulus polyphemus. ... This reaction is the basis of the LAL test, which is widely used for the detection and quantification of bacterial endotoxins.

Regarding this, Which bacteria produce strong positive result in LAL test?. Limulus amebocyte lysate test is an aqueous extract of blood cells (amoebocytes) which obtain from the horseshoe crab ( Limulus polyphemus ). LAL reagent reacts with the bacterial endotoxins or lipopolysaccharide (LPS).

One may also ask, How is LAL test done?

Test procedure: A BET involves analyzing the liquid sample or sample extract using Limulus Amebocyte Lysate (LAL). LAL is a reagent made from the blood of the horseshoe crab. In the presence of bacterial endotoxins, the lysate reacts to form a clot or cause a color change depending on the technique.

How is Limulus lysate extracted?

The lysate is produced by extracting blood from the crab. This is done using a non-lethal method where blood is taken from a large dorsal blood sinus, the pericardium. The crabs are returned to the water within 24 hours and completely recover.

29 related questions found

What is the basic principle of Limulus lysate test?

The principle of the LAL test is a reaction between LPS and a substance (clottable protein) contained within amoebocyte cells derived from the blood of the horseshoe crab, as illustrated in Figure 11.4 (of which Limulus polyphemus is the most commonly used species, although other species, such as Carcinoscorpius and ...

What is limulus amebocyte lysate used for?

The limulus amebocyte lysate (LAL) has been widely used for ~30 years for the detection of endotoxin in the quality assurance of injectable drugs and medical devices. The LAL constitutes a cascade of serine proteases which are triggered by trace levels of endotoxin, culminating in a gel clot at the end of the reaction.

How do you detect endotoxin?

Therefore, it is essential to develop sensitive, accurate, and rapid methods for its detection. The rabbit pyrogen test is the first standard technique for endotoxin detection and, nowadays, has been replaced by the Limulus Amoebocyte Lysate test, which is the most popular detection technique for endotoxin.

Why LAL test is done?

The LAL test (acronym for Limulus Amebocyte Lysate) is a test for the determination of bacterial endotoxins, which uses an Amebocyte Lysate of the Limulus crab.

How can I lower my endotoxin levels?

The most common depyrogenation procedures for physical components include incineration and removal by washing, also termed dilution. The literature has shown other procedures, such as filtration, irradiation and ethylene oxide treatment to have limited effect in reducing pyrogen/endotoxin levels.

What are examples of Exotoxins?

(Science: protein) toxin released from gram-positive and gram-negative bacteria as opposed to endotoxins that form part of the cell wall. Examples are cholera, pertussis and diphtheria toxins.

What symptoms do endotoxins cause?

The human health effects of acute exposure to endotoxin include sepsis; clinical symptoms such as fever, shaking chills, and septic shock; and, at lower doses, toxic pneumonitis, lung function decrements, and respiratory symptoms, such as byssinosis (“Monday morning chest tightness”) (Rylander 2002, 2006).

What are examples of endotoxins?

Although the term "endotoxin" is occasionally used to refer to any cell-associated bacterial toxin, in bacteriology it is properly reserved to refer to the lipopolysaccharide complex associated with the outer membrane of Gram-negative pathogens such as Escherichia coli, Salmonella, Shigella, Pseudomonas, Neisseria, ...

What causes Lal?

Lipopolysaccharides, which are chemical species that are considered toxic upon producing the cell lysis of Gram-negative bacteria, activate a series of chain reactions that occur in the hemolymph of horseshoe crab, finally causing turbidity in the sample. This is the analytic signal used to develop the LAL test.

Why LAL test is so popular with the pharma industries?

One of the reasons that has made the LAL test prevail in the pharmaceutical industry is the careful avoidance by the LAL manufacturers of bringing harm to live animals during both production and testing. ... In these cases, the LAL test has made it possible to conduct the detection of the endotoxins without any problems.

What is the importance of pyrogen test?

Pyrogen test is performed to check the presence or absence of pyrogens in all aqueous parenterals. Rabbits are used to perform the test because their body temperature increases when pyrogen is introduced by the parenteral route. For this test, three healthy rabbits are selected each weighing at least 1.5 kg.

What causes endotoxin?

Source and Exposure. Endotoxin is found in Gram-negative bacteria and bacterial products or debris. Thus, endotoxin is widely present in the environment, including dust, animal waste, foods, and other materials generated from, or exposed to, Gram-negative bacterial products.

Who discovered LAL?

Discovery of the Limulus Amebocyte Lysate (LAL) test. This is a story of two remarkable men, Dr. Frederik Barry Bang, a pioneer in applying marine biology to medical research, and Jack Levin, who invented the LAL test in the mid 20th century.

How do you calculate endotoxin MVD?

Think about it this way:
  1. If the dose is 1 mg/kg/hr, the endotoxin limit is (5 EU/kg/hr) ÷ (1 mg/kg/hr) = 5 EU/mg.
  2. If the dose is 10 mg/kg/hr, the endotoxin limit is (5 EU/kg/hr) ÷ (10 mg/kg/hr) = 0.5 EU/mg.
  3. If the dose is 100mg/kg/hr, the endotoxin limit is (5 EU/kg/hr) ÷ (100 mg/kg/hr) = 0.05 EU/mg.

What is a bacterial endotoxin test?

The bacterial endotoxins test (BET) is a test to detect or quantify endotoxins from Gram- negative bacteria using amoebocyte lysate from the horseshoe crab (Limulus polyphemus or. Tachypleus tridentatus).

What is the difference between endotoxin and pyrogen?

Endotoxins are an important type of pyrogens. ... The key difference between endotoxin and pyrogen is that endotoxin is a lipopolysaccharide found in the outer membrane of gram negative bacteria while pyrogen is a polypeptide or polysaccharide which induces fever when released into circulation.

What is LAL reagent?

FDA-licensed LAL Reagents. Limulus amebocyte lysate (LAL) is an aqueous extract of blood cells (amebocytes) from the Atlantic horseshoe crab, Limulus polyphemus.

What does Lal stands for in pharmacy?

The LAL (limulus amebocyte lysate) testing, also known as bacterial endotoxin testing, is an in vitro assay used to detect the presence and concentration of bacterial endotoxins in drugs and biological products, and is an important part of pharmaceutical microbiology.

How do you test for pyrogens?

Two widely used pyrogen test methods are the rabbit pyrogen test (RPT) and the bacterial endotoxin test (BET) based on Limulus Amebocyte Lysate (LAL). Both tests have their limitations. The RPT can miss human-specific pyrogens, does not allow for quantification and requires the use of animals.

What is minimum valid concentration?

The minimum valid concentration (MVC) is the product concentration at the MVD. ... When this product is diluted by a factor of twenty, the endotoxin concentration in the dilution is 0.25 EU/ml, which is detectable and the product will fail the test. At greater dilutions, the endotoxin will not be detectable.