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431.
432.
A potential diagnostic reagent for bovine cysticercosis 总被引:1,自引:0,他引:1
M L Rhoads K D Murrell G W Dilling M M Wong N F Baker 《The Journal of parasitology》1985,71(6):779-787
A fraction of larval Taenia hydatigena cyst fluid was shown to have high sensitivity and specificity in the enzyme-linked immunosorbent assay (ELISA) for the detection of bovine antibodies to the heterologous parasite Taenia saginata. This antigenically active lipoprotein fraction was isolated by ultracentrifugal density flotation using either ammonium sulfate (specific gravity = 1.231 g per ml) or NaCl/KBr (specific gravity = 1.225 g per ml), followed by ion-exchange chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) indicated that this fraction was composed of high molecular weight (65,000 to 77,000 Mr) and low molecular weight (9,500 to 16,000 Mr) proteins. Electrophoresis under non-denaturing conditions in either acrylamide (5%) or agarose (1%) resulted in 1 major diffuse band staining for both protein and lipid. The high and low molecular weight proteins observed on SDS-PAGE under reducing conditions could not be resolved by gel filtration chromatography and emerged as a single lipoprotein peak. This T. hydatigena cyst fluid fraction appears promising as a diagnostic reagent in the ELISA for bovine cysticercosis. 相似文献
433.
Ian R. McDonald Levente Bodrossy Yin Chen J. Colin Murrell 《Applied microbiology》2008,74(5):1305-1315
434.
Comparison of three subspecies of Trichinella spiralis by scanning electron microscopy 总被引:2,自引:0,他引:2
The surface morphology of three subspecies of Trichinella spiralis was examined by SEM in an attempt to find characteristics useful for distinguishing the subspecies. The subspecies studied were T. spiralis spiralis, which had been maintained in swine and laboratory animals for about 50 yr; T. spiralis nativa collected from Ursus maritimus at 58 degrees N latitude and 95 degrees W longitude in 1976; and, T. spiralis pseudospiralis, which was derived from the original isolation of this subspecies from Procyon lotor at 43 degrees N latitude and 47 degrees 30'E longitude in 1972. All three subspecies were passed in CFW mice and adult worms were collected from the small intestine at 4, 5, 6, 7, 8, and 11 days PI. Characteristics examined included labial and cephalic papillae, cuticular ridges and folds, hypodermal gland cell pores, pseudobursal lobes, genital papillae, cloacal aperture, copulatory bell and vulval morphology. Previous reports of subspecies differences within Trichinella spiralis in the number and distribution of hypodermal gland cell pores, position of genital papillae, shape of the cloacal aperture and shape of pseudobursal lobes were not confirmed and are believed to have been in error resulting from artifacts of fixation and a lack of knowledge of variations within the subspecies caused by low numbers of samples. Differences in surface morphology were not found among the three subspecies. The available names of the recognized biological populations of Trichinella were used at the subspecies level rather than species level because this more clearly represents the state of our knowledge of the nematodes. The question of whether the epidemiology of trichinosis is complicated by the presence of more than one species has not been answered, and it is important that our nomenclature reflect this. 相似文献
435.
Levente Bodrossy E. M. Holmes A. J. Holmes Kornél L. Kovács J. C. Murrell 《Archives of microbiology》1997,168(6):493-503
Two methanotrophic bacteria with optimum growth temperatures above 40° C were isolated. Thermotolerant strain LK6 was isolated
from agricultural soil, and the moderately thermophilic strain OR2 was isolated from the effluent of an underground hot spring.
When compared to the described thermophilic methanotrophs Methylococcus capsulatus and Methylococcus thermophilus, these strains are phenotypically similar to Methylococcus thermophilus. However, their 16S rRNA gene sequences are markedly different from the sequence of Methylococcus thermophilus (∼ 8% divergence) and, together with Methylomonas gracilis, they form a distinct, new genus within the γ-subgroup of the Proteobacteria related to extant Type I methanotrophs. Further
phenotypic characterisation showed that the isolates possess particulate methane monooxygenase (pMMO) but do not contain soluble
methane monooxygenase. The nucleotide sequence of a gene encoding pMMO (pmoA) was determined for both isolates and for Methylomonas gracilis. PmoA sequence comparisons confirmed the monophyletic nature of this newly recognised group of thermophilic methanotrophs
and their relationship to previously described Type I methanotrophs. We propose that strains OR2 and LK6, together with the
misclassified thermophilic strains Methylomonas gracilis VKM-14LT and Methylococcus thermophilus IMV-B3122, comprise a new genus of thermophilic methanotrophs, Methylocaldum gen. nov., containing three new species: Methylocaldum szegediense, Methylocaldum tepidum and Methylocaldum gracile.
Received: 2 April 1997 / Accepted: 23 July 1997 相似文献
436.
437.
Conditions were established for recovery of active schistosomules of Schistosoma mansoni after cryopreservation and storage in liquid nitrogen (?196 C). Schistosomules prepared from cercariae by a shear pressure technique were subjected to a two-step cooling process consisting of a slow cooling rate to an intermediate temperature, followed by rapid quenching of the sample in liquid nitrogen. Overall averages of 39 and 44% of the schistosomules, with a maximum of 88%, were recovered retaining normal activity with cooling rates of 0.4 C/min to ?32 C or 0.8 C/min to ?35 C, respectively. Methanol at 17.5% in Earle's lactalbumin hydrolysate was the freezing medium. As compared with 24 hr storage in liquid nitrogen, no loss in schistosomule motility was observed after 1 month. Following cryopreservation, attenuated schistosomules derived from 60Co-irradiated cercariae (50 kR) exhibited structure and activity equivalent to that of unattenuated schistosomules. Infectivity for mice of unattenuated schistosomules derived from 60Co-irradiated cercariae (50 Krad) exhibited structure and activity of unfrozen schistosomules ranged from 0.4 to 15.2%. 相似文献