ABSTRACT
The aqueous layer was isolated from Leptospira interrogans serovar canicola strain Moulton by the hot phenol-water method. After ultracentrifugation, the precipitate was designated as lipopolysaccharide-like substance (LLS) fraction and the chemical composition was compared with that of bacterial LPS. The LLS fraction consists of 35.2% carbohydrate, 3.8% amino sugar, 36.4% lipid, 15.2% protein, and 0.3% phosphorus. Neutral sugars were detected as rhamnose, arabinose, xylose, 4-O-methylmannose, mannose, galactose, and a small amount of erythrose, fucose and glucose by gas-liquid chromatography (GLC), but 2-keto-3-deoxyoctonic acid was not detected in the LLS by thiobarbituric acid test and high voltage paper electrophoresis. Fatty acids detected by GLC were decanoic acid (C10: 0), dodecanoic acid (C12: 0), dodecenoic acid (C12: 1), tridecenoic acid (C13: 1), tetradecanoic acid (C14: 0), hexadecanoic acid (C16: 0), hexadecenoic acid (C16: 1), and octadecenoic acid (C18: 1). With SDS-polyacrylamide gel electrophoresis, bacterial LPS showed many orderly bands, while the banding pattern of the leptospiral LLS was very simple. These findings demonstrate that the physicochemical properties and chemical composition of LLS fraction from Leptospira are different from those of LPS extracted from gram-negative bacteria such as Enterobacteriaceae, and suggesting that Leptospira has no typical LPS.
Subject(s)
Leptospira interrogans/analysis , Lipopolysaccharides/analysis , Amino Sugars/analysis , Bacterial Proteins/analysis , Carbohydrates/analysis , Chromatography, Gas , Electrophoresis, Paper , Electrophoresis, Polyacrylamide Gel , Fatty Acids/analysis , Lipids/analysis , Phosphorus/analysis , Sugar Acids/analysisABSTRACT
The biological activities of lipopolysaccharide-like substance (LLS) extracted from Leptospira interrogans serovar canicola strain Moulton by the hot phenol-water method were studied in mice. The addition of 12.5 micrograms/ml or more of LLS fraction increased the incorporation of [3H]thymidine into in vitro cultured spleen cells of C57BL/6 mice, while the activity of the LLS fraction was about 20 times weaker than that of Salmonella typhimurium lipopolysaccharide (LPS). Pretreatment of murine spleen cells with rabbit anti-mouse thymocyte antiserum did not diminish the mitogenic activity of leptospiral LLS, and the LLS could not increase the incorporation of [3H]thymidine into thymocytes, suggesting that LLS acts on a B-lymphocyte population of lymphocytes. When sheep erythrocytes and LLS fraction were injected intraperitoneally into BALB/c mice, LLS exhibited an enhancing effect on antibody response in vivo. However, lethal toxicity of the LLS fraction was about 500 times lower than that of LPS in C57BL/6 mice loaded with galactosamine. No antitumor activity of leptospiral LLS (250-1,000 micrograms/mouse) against the ascites form of Ehrlich carcinoma in ddY mice was observed. The biological activities of the LLS fraction from the organism were weaker than those of gram-negative bacterial LPS, suggesting that Leptospira possesses no typical LPS.
Subject(s)
Adjuvants, Immunologic/pharmacology , Antineoplastic Agents/pharmacology , Leptospira interrogans , Lipopolysaccharides/pharmacology , Mitogens/pharmacology , Animals , B-Lymphocytes/drug effects , Cells, Cultured , Female , Lipopolysaccharides/immunology , Lipopolysaccharides/toxicity , Lymphocyte Activation/drug effects , Male , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , T-Lymphocytes/drug effectsSubject(s)
Adjuvants, Immunologic , Mitogens , Polysaccharides, Bacterial/pharmacology , Vibrio/immunology , Animals , Female , Male , Mice , Mice, Inbred BALB C , Mice, Inbred C57BLABSTRACT
The late auditory evoked potential has been shown to be influenced by lesions located within the frontal or temporal-parietal cortex. The present study was conducted to determine which combination of test parameters produced the most reliable late responses in neurologically normal patients as a preliminary to clinical application. The results of this study revealed a combination of test parameters which demonstrated minimal across-subject and between-test session variance. This combination of test parameters was subsequently recommended for clinical use.
Subject(s)
Cerebral Cortex/physiology , Electroencephalography , Evoked Potentials, Auditory , Adult , Auditory Pathways/physiology , HumansABSTRACT
The purpose of this study was to investigate intra- and intermodal discrimination generalization-transfer in auditory and visual "same-different" discrimination training. Two subjects were trained in an auditory discrimination task, two in a visual discrimination task and two received no training. Discrimination performance was assessed on 12 visual and 12 auditory stimulus conditions at pre- and posttraining intervals for all subjects. The 4 subjects receiving training also were probed for performance at three intervals during the training. Results indicate that subjects trained to a task in one sensory modality demonstrate improved discrimination performance on untrained stimulus discrimination within (intra-) and between (inter-) sensory modalities, whereas, untrained subjects tended to show less improved performance.
