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Biomedical subjects

R M Lemcke

Publications and source records attributed to R M Lemcke.

At least 19 recordsLinked to original sources

Analysis of the axial filaments of Treponema hyodysenteriae by SDS-PAGE and immunoblotting.

Purified axial filaments from eight serotypes of Treponema hyodysenteriae and two non-pathogenic intestinal spirochaetes were characterized by SDS-PAGE and Western blotting. Axial filaments of all ten strains had similar SDS-PAGE profiles; five major axial filament polypeptides were identified, with molecular masses of 43.8, 38, 34.8, 32.8 and 29.4 kDa. Hyperimmune gnotobiotic pig serum raised against purified axial filaments of strain P18A (serotype 4) cross-reacted with all other serotypes and with the non-pathogens, and convalescent serum taken from a pig with persistent swine dysentery also showed a strong response to the axial filament polypeptides. Hyperimmune gnotobiotic pig serum raised against axial filaments failed to agglutinate viable organisms and did not inhibit growth in vitro. Hence, the axial filaments of T. hyodysenteriae have been identified as major immunodominant antigens, although the role that antibodies to these antigens play in protection has yet to be established.

Animals

Production, purification and molecular weight determination of the haemolysin of Treponema hyodysenteriae.

The production of haemolysin from Treponema hyodysenteriae was increased by an improved culture method and by repeated incubation of spirochaetes suspended in a buffer containing RNA-core. Ion exchange chromatography on DEAE cellulose followed by gel filtration on Sephadex G100 yielded purified haemolysin free from extraneous protein, as judged by silver-stained polyacrylamide gels. The mol. wt of the purified haemolysin, determined by gel filtration was 19,000, a value similar to that of streptolysin S, but much lower than that previously reported.

Animals

Identification of Treponema hyodysenteriae by a rapid slide agglutination test.

A rapid slide agglutination (SA) test was developed to identify the spirochaete Treponema hyodysenteriae, the causative organism of swine dysentery. The specificity of the antiserum was increased by a single absorption with two intestinal spirochaetes. Using this test, it was possible to identify 30 out of 31 spirochaetes which were beta-haemolytic and gave a positive reaction in growth inhibition (GI) tests with T hyodysenteriae antiserum. All except one of these spirochaetes were isolated from herds with a history of swine dysentery or suspected swine dysentery. The majority of the spirochaetes gave a rapid, strongly, positive reaction in the SA test but seven strains, although recognisably positive, reacted more weakly. Of 28 other spirochaetes which were weakly beta-haemolytic and did not react in GI tests with T hyodysenteriae antiserum, 27 were negative in the SA test. The remaining strain was autoagglutinable and thus could not be identified. The indole test correlated less well with the results of SA and GI tests. All 31 strains which were identified as T hyodysenteriae produced indole, but so did nine of the 28 other spirochaetes. The slide agglutination test is a potentially useful method for rapid identification of T hyodysenteriae.

Agglutination Tests

The relationship of two equine mycoplasmas to Mycoplasma mycoides.

Two unidentified mycoplasmas, N3 and N11, isolated from the respiratory tract of horses, were found to cross-react with strains of M. mycoides subsp. mycoides in indirect immunofluorescence tests, growth-inhibition tests carried out by the running drop/agar-well method, and in complement-fixation and double immunodiffusion tests. Serologically, the equine mycoplasmas were not completely identical with any of the reference strains of M. mycoides with which they were compared. Their cultural characteristics, ability to digest coagulated serum and casein, and survival at 45 degrees C, however, suggested that they were more closely related to strains of M. mycoides subsp. mycoides, such as Y-goat, which are found in goats, than to strains of that subspecies which are pathogenic for cattle.

Animals

Sterol requirement for the growth of Treponema hyodysenteriae.

The addition of cholesterol to a liquid medium containing bovine serum albumin (BSA) fraction V or acetone-delipidized BSA fraction V instead of serum stimulated the growth of Treponema hyodysenteriae, a serum-requiring spirochaete associated with swine dysentery. As little as 1.25 micrograms cholesterol ml-1 increased viable counts about 1000-fold. Sitosterol and cholestanol, but not pregnenalone, cholestenone or stigmasteriol, produced a growth response comparable to that of cholesterol. The results suggest that T. hyodysenteriae requires a sterol for growth.

Cholesterol

Isoenzymes in two species of Acholeplasma.

The reference strains Type A and Type B and two equine strains of Acholeplasma laidlawii were examined for a wide range of isoenzymes using thin-layer starch-gel electrophoresis; in addition two isoenzymes were examined in two strains of A. equifetale. The type strains A and B of A. laidlawii were differentiated by their lactate dehydrogenase, phosphoglucomutase and aspartate aminotransferase patterns and the two equine strains by their hexokinase, lactate dehydrogenase and phosphoglycerate kinase patterns. The two pairs of strains differed from one another with respect to hexokinase, phosphoglucomutase, adenylate kinase and glucose-6-phosphate dehydrogenase. The two strains of A. equifetale could be distinguished by their isoenzymes of hexokinase. The two species were differentiated by their hexokinase and phosphoglucomutase patterns.

Acholeplasma

A disc growth-inhibition test for differentiating Treponema hyodysenteriae from other intestinal spirochaetes.

A disc growth-INHIBITION (GI) test was developed for differentiating Treponema hyodysenteriae from other intestinal spirochaetes. Tests with antisera against six spirochaetes, including two strains of T hyodysenteriae revealed four serological types among the six strains. The two strains of T hyodysenteriae represented one type. The test was specific in that there were no cross-reactions between the four types. Using antisera to two strains of T hyodysenteriae, it was possible to distinguish 11 strains isolated from cases of swine dysentery from nine other intestinal spirochaetes, seven from pigs, one from a cat and one from a chicken. The GI test seems to have potential as a simple, specific screening test for T hyodysenteriae.

Animals

The growth of Treponema hyodysenteriae and other porcine intestinal spirochaetes in a liquid medium.

A new simple method for the preparation of a liquid medium containing rabbit serum for the propagation of Treponema hyodysenteriae and other porcine intestinal spirochaetes is described. The medium, when dispensed in shallow layers and sealed under 10 per cent CO2 in nitrogen, had a redox potential not greater than -125mV and an initial pH of about 6.9 when buffered with bicarbonate. Growth of T hyodysenteriae developed more rapidly and viable counts reached higher levels at 42 degrees C than at 37 degrees C. Viable counts increased at least 10,000-fold after two to five days' incubation, depending on the temperature. Growth could be initiated from small inocula that failed to produce colonies on blood agar. Using a 1 per cent inoculum, the medium supported the growth of two strains of T hyodysenteriae through 10 serial passages.

Animals

Mycoplasmas isolated from the respiratory tract of horses.

Ten mycoplasmas were isolated from 130 nasopharyngeal swabs from thoroughbred horses with acute respiratory disease and three from 198 apparently normal horses. Two mycoplasmas were isolated from 21 tracheal swabs taken at necropsy. These mycoplasmas, together with six isolated from the equine respiratory tract by other workers, were subjected to biochemical and serological tests. Other properties examined in certain representative strains were appearance under the electron microscope, ability to adsorb or agglutinate the erythrocytes of various animal species and the electrophoretic pattern of the cell proteins. On the basis of these test, mycoplasmas from the equine respiratory tract were divided into seven species. Three species belonged to the genus Acholeplasma, members of which do not require sterol for growth, and were identified as A. laidlawii, A. oculi (formerly A. oculusi) originally isolated from the eyes of goats, and a recently named species A. equifoetale, previously isolated from aborted equine fetuses. Of the four sterol-dependent Mycoplasma species, one was indentified as M. pulmonis, a common rodent pathogen. Another cross-reacted serologically with M. felis and should probably be classified as that species. The other two species probably represent new species peculiar to the horse. One of these, represented by the strains N3 and N11, ferments glucose and is serologically distinct from 19 recognized species of glucose-utilizing mycoplasmas and from two species which do not metabolize either glucose or arginine. The other species, represented by four strains, hydrolyses arginine and, because it is serologically distinct from all the named arginine-hydrolysing Mycoplasma species, the name M. equirhinis sp.nov. is proposed for it. Of the seven species, only M. pulmonis and the glucose-utilizing species represented by N3 and N11 were found exclusively in horses with acute respiratory disease. A. oculi was isolated from an apparently normal horse. The other four species were found in normal horses as well as those with respiratory disease, although three out of the four strains of M. equirhinis were from sick horses.

Acute Disease