The "Limulus" Amebocyte Lysate Test for Endotoxin

Pearson, Frederick C.; Weary, Marlys

doi:10.2307/1307948

Cited by 11 publications

(4 citation statements)

References 8 publications

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“…The LAL test is a very sensitive assay for the detection of bacterial endotoxin (33,34). The lipid moiety of LPS is believed to be associated with LAL reactivity (23,51).…”

Section: Discussionmentioning

confidence: 99%

Cell Wall Characteristics of Mobiluncus Species

Carlone

Thomas

Arko

et al. 1986

International Journal of Systematic Bacteriology

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The three type strains and a reference strain of Mobiluncus examined in this study had a gram-positive type of cell walls. All four strains were susceptible to vancomycin and resistant to colistin, and the overall susceptibility patterns with other antimicrobial agents were consistent with those of gram-positive microorganisms. Strains of Mobiluncus mulieris were lysed by 3% potassium hydroxide, and strains of Mobiluncus curtisii were not. However, all of the strains examined had intermediate levels of Limulus amebocyte-lysate reactivity that was not lipopolysaccharide associated. Lipopolysaccharide was not detected when whole-cell lysates were digested with proteinase K, separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and silver stained. In addition, 2-keto-3-deoxyoctulosonic acid and heptose were not detected by gas chromatography of 0-methyloxime acetate derivatives of whole-cell carbohydrates. Saponification and gas chromatography of whole-cell fatty acids showed that none of the four strains examined had detectable levels of hydroxylated fatty acids. Hydroxylated fatty acids or aldehyde fatty acids were not detected in acid hydrolysates of crude cell membrane preparations. (1,4,17,27,30,35,37,39,41,45,48), although the taxonomic position of members of this genus is still unresolved (15,43).The genus Mobiluncus has been tentatively assigned to the family Bacteroidaceae (43), which includes obligately anaerobic straight, curved, or helical gram-negative and gram-positive rod-shaped bacteria (18). The Gram reactions of strains of Mobiluncus are typically gram negative or variable (15, 43), although electron micrographs show that structurally these organisms have gram-positive cell walls (41, 43) and lack an outer membrane. Likewise, anaerobic curved rod-shaped organisms belonging to the genera Butyrivibrio, Lachnospira, and Acetivibrio (B), which are also members of the family Bacteruidaceae, stain gram negative but are structurally gram positive. Among anaerobic curved rods consistent with Mobiluncus, fatty acid aldehydes (presumably from plasmologens) have been detected, while hydroxlated fatty acids (found predominately in gram-negative bacteria) have not been found (39). Mobiluncus species are resistant to some antimicrobial agents which traditionally inhibit gram-negative microorganisms and are susceptible to some antimicrobial agents which inhibit gram-positive microorganisms (1,8,15,42,43,44). Limulus amebocyte lysate (LAL) reactivity, an indicator of gram-negative endotoxin, has also been reported (29).In this study, we compared characteristics of the type * Corresponding author.strains and a reference strain of Mobiluncus since previous reports have included organisms of undetermined taxonomic position which resemble members of this genus. We examined four strains of Mobiluncus for the following characteristics which are indicative of cell wall type: cell lysis, lipopolysaccharide (LPS), endotoxin reactivity, fatty acid content, antimicrobial agent susceptibility, and carbohyd...

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“…The LAL test is a very sensitive assay for the detection of bacterial endotoxin (33,34). The lipid moiety of LPS is believed to be associated with LAL reactivity (23,51).…”

Section: Discussionmentioning

confidence: 99%

Cell Wall Characteristics of Mobiluncus Species

Carlone

Thomas

Arko

et al. 1986

International Journal of Systematic Bacteriology

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“…For the IV tracer infusion, all tracers were prepared in normal saline and passed through a 0.22-m filter (Millipore, Bedford, MA) under a laminar flow hood and then dispensed into single-dose vials. Each batch of infusates was sterile and pyrogen free by the limulus amebocyte lysate test (31). The tracers for oral administration were prepared in deionized water and stored at Ϫ20°C until used.…”

Section: Methodsmentioning

confidence: 99%

Oral and Intravenous Tracer Protocols of the Indicator Amino Acid Oxidation Method Provide the Same Estimate of the Lysine Requirement in Healthy Men

Kriengsinyos

Wykes

Ball

et al. 2002

The Journal of Nutrition

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To investigate whether splanchnic uptake of the indicator amino acid ([1-(13)C] phenylalanine) during the fed state alters the estimate of lysine requirement, five healthy men were studied at graded levels of lysine intake, with either an oral or intravenous (IV) tracer protocol, in a randomized, crossover design. Splanchnic extraction of the oral tracer was expressed as the difference between the ratio of the enrichments in urinary phenylalanine between tracer protocols. The rate of release of (13)CO(2) from (13)C-phenylalanine oxidation (F(13)CO(2)) was measured and a two-phase linear regression crossover model was applied to determine the lysine requirement. Mean splanchnic extraction of the oral tracer was approximately 19%. Although actual F(13)CO(2) was higher during oral tracer infusion (P < 0.001), the breakpoint was not different from that determined with IV infusion (P = 0.98), with both yielding a mean lysine requirement of 36.6 mg/(kg. d). The upper 95% confidence intervals were 52.5 and 53.3 mg/(kg. d) for the oral and IV isotope infusions, respectively. These results demonstrate that routes of isotope administration using the indicator amino acid oxidation technique do not affect the estimated amino acid requirement. Therefore, the indicator amino acid oxidation method using the oral route, which is less invasive and allows for studies in vulnerable groups such as infants and children, should be the preferred method for studying amino acid requirements.

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“…The end-point chromogenic endotoxin assay kit was applied to investigate the binding ability of peptides to LPS. The gradient concentration of peptide was mixed in equal volume with 0.4 ng/mL of control standard endotoxin (CSE) and incubated for 0.5 h. Subsequently, the mixture was added to a 96-well plate, and the end-point chromogenic endotoxin assay kit was used to detect peptide binding to LPS . The absorbance of the sample was tested at 450 nm.…”

Section: Methodsmentioning

confidence: 99%

Design of a Novel Lysine Isopeptide 1018KI11 with Potent Antimicrobial Activity as a Safe and Stable Food Preservative Candidate

Wang,

Yang,

Dong

et al. 2024

J. Agric. Food Chem.

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Antimicrobial peptides are potent food additive candidates, but most of them are sensitive to proteases, which limits their application. Therefore, we substituted arginine for lysine and introduced a lysine isopeptide bond to peptide IDR-1018 in order to improve its enzymatic stability. Subsequently, the protease stability and antimicrobial/antibiofilm activity of the novel peptides (1018K2−1018KI11) were investigated. The data revealed that the antienzymatic potential of 1018KI11 to bromelain and papain increased by 2−8 folds and 16 folds, respectively. The minimum inhibitory concentration (MIC) of 1018KI11 against methicillinresistant Staphylococcus aureus (MRSA) ATCC43300 and Escherichia coli (E. coli) ATCC25922 was reduced 2-fold compared to 1018K11. Mechanism exploration suggested that 1018KI11 was more effective than 1018K11 in disrupting the cell barrier and damaging genomic DNA. Additionally, 1018KI11 at certain concentration conditions (2−64 μg/mL) reduced biofilm development of MRSA ATCC43300 by 4.9−85.9%. These data indicated that novel peptide 1018KI11 is a potential food preservative candidate.

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The "Limulus" Amebocyte Lysate Test for Endotoxin

Cited by 11 publications

References 8 publications

Cell Wall Characteristics of Mobiluncus Species

Cell Wall Characteristics of Mobiluncus Species

Oral and Intravenous Tracer Protocols of the Indicator Amino Acid Oxidation Method Provide the Same Estimate of the Lysine Requirement in Healthy Men

Design of a Novel Lysine Isopeptide 1018KI11 with Potent Antimicrobial Activity as a Safe and Stable Food Preservative Candidate

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