Comparison of OspA Serotypes for Borrelia burgdorferi Sensu Lato from Japan,Europe and North America

Sixty-one Borrelia burgdorferi sensu lato strains from various sources (ticks, human, and wild animals) in Japan and two strains from ticks in Far Eastern Russia were classified on the basis of reactivity with 16 monoclonal antibodies (mAb) to outer surface protein A (OspA) and by DNA-DNA hybridization assay. Eleven OspA serotypes (J1 to J11) were recognized among the Japanese and the Far East Russian isolates (serotypes J1 to J9 were identified as B. garinii, serotype J10 was identified as B. afzelii, and serotype J11 corresponded to B. japonica), whereas 7 OspA serotypes for North American and European isolates previously reported (Bettina Wilske et al, J. Clin. Microbiol. 31:340-350, 1993) were not observed except for OspA serotype 2 which showed identical reactivity with OspA serotype J10. This finding provides helpful information for understanding the geographical distribution of Lyme disease borrelia and the development of vaccine and diagnostic tests. In conclusion: 1. B. burgdorferi sensu stricto has not been observed in Japan, 2. Japanese B. afzelii isolates are closely related to those from Europe, 3. B. garinii isolates from Japan are highly heterogeneous and apparently different from European B. garinii isolates.     

CHARACTERIZATION OF MORPHOSPECIES AND STRAINS OF MICROCYSTIS (CYANOBACTERIA) FROM NATURAL POPULATIONS AND LABORATORY CLONES USING CELL PROBES (LECTINS AND ANTIBODIES)1

The genus Microcystis (cyanobacteria) includes toxic and bloom-forming morphotypes which are usually arranged into species based on morphological features. Immunofluorescence assays using polyclonal and preadsorbed antibodies, as well as FITC-labebd lectins were used to characterize three morphospecies of Microcystis (M. viridis, M. wesenbergii, and M. aeruginosa) from natural populations (several lakes/reservoirs in Denmark and Spain) and laboratory clones. The cell probes used were unaffected by the different phases of the cell division cycle, growth phase, or environmental factors, such as culture medium, light, or temperature. Anhbody and lectin binding patterns were specific to each clone. In nature, the cell probes were useful tools to characterize Microcystis populations. Antibodies and lectins revealed geographic differentiation within the same morphospecies. Differentiation was moderate among nearby locales and intensified among areas distant from one another. Microcystis aeruginosa from Spain has very different cell surface antigens and lectin binding sites than M. aeruginosa from Denmark. A taxonomy of Microcystis based on cell probes reveals some discrepancies with classical morphospecies. The binding affinities were more closely related to the geographic origin of the tested material than to the morphospecies identification. Different morphospecies from the same lake in some cases were more similar than the same morphospecies from different lakes. Microcystis viridis and M. aeruginosa from Danish lakes appeared to be closely related species, whereas M. wesenbergii emerged as a different species.     

MORPHOSPECIES VS. GENOSPECIES IN TOXIC MARINE DINOFLAGELLATES: AN ANALYSIS OF GYMNODZNIUM CATENATUM/GYRODINIUM IMPUDICUM AND ALEXANDRIUM MINUTUM/A. LUSITANICUM USING ANTIBODIES,LECTINS, AND GENE SEQUENCES1

Morphological features are the predominant criteria used to define species of marine dinoflagellates. Taxonomic problems with some toxic groups has led to the implementation of molecular taxonomy techniques and development of a genospecies concept. As a result, the relationships between “morphospecies” and “genospecies” has been questioned. In this study, the genetic differentiation between two sets of closely related morphospecies, Gymnodinium catenatum Graham/Gyrodinium impudicum Fraga and Alexandrium minutum Halim/Alexandrium lusitanicum Balech, were analyzed. The extent of morphological differentiation existing within these two groups is of the same order of magnitude. Analysis of cell surface antigens detected by preadsorbed serum, cell surface glycan moieties detected by lectins and sequencing of the D9 and D10 domains of the Large-subunit ribosomal RNA gene, showed that the extent of genetic differentiation existing between the dinofagellates Gymnodinium catenatum/Gyrodinium impudicum is substantial. Therefore, both morphological and genetic criteria resolve these organisms as two distinct entities. In contrast, Alexandrium minutum/Alexandrium lusitanicum were indistinguishable using the some suite of molecular markers. The findings demonstrated that classifications based on morphological criteria may be incongruous. On a practical level, molecular taxonomy provides useful tools to distinguish between morphologically similar microalgal species and furthermore can prevent misidentification of species such as Gymnodinium catenatum/Gyrodinium impudicum, a frequent occurrence when samples are fixed with Lugol's or formaldehyde solution.     

Borrelia Burgdorferi Sensu Lato in Ixodes Ricinus Ticks and Rodents in a Recreational Park in South-Western Ireland

Ixodes ricinus ticks infected with Borrelia burgdorferi sensu lato were numerous on the edges of paths and roads in a recreational park in south-western Ireland. The abundance of ticks at different sites was related to the presence of deer, but a negative relationship was shown between tick abundance and tick infection rates. This is thought to be due to the deposition of large numbers of uninfected ticks by deer, which are apparently not good reservoir hosts of B. burgdorferi s.l. Blood meal analysis only detected deer DNA in uninfected nymphs. Reservoir competent rodents, Apodemus sylvaticus and Clethrionomys glareolus, were abundant at all sites and a high proportion of captured specimens were infested with larval ticks. However, very few rodents were infected with B. burgdorferi s.l. and none of the unfed infected nymphs analysed for the identity of their larval blood meal had fed on rodents. The spirochaetes detected in I. ricinus in the study area may be poorly adapted to rodents or are not transmitted readily because of the absence of nymphal infestation. The majority of spirochaetes in these ticks were apparently acquired from non-rodent hosts, such as birds.     

Review The ecology of ticks transmitting Lyme borreliosis

The main vectors of Borrelia burgdorferi sensu lato, the cause of Lyme borreliosis, are ixodid ticks of the Ixodes persulcatus species complex. These ticks, which occur throughout the northern temperate zone, have very similar life cycles and ecological requirements. All are three-host ticks, with the immature stages mainly parasitizing small to medium-sized mammals and birds and the adult females parasitizing large mammals such as deer, cattle, sheep and hares. The host-seeking stages show a distinct seasonality, which is regulated by diapause mechanisms and there appear to be major differences in this respect between the Old World and New World species. Most cases of human borreliosis are transmitted in the summer by the nymphal stages, with the exception of the Eurasian species, I. persulcatus, in which the adult females are mainly responsible. The ticks acquire the spirochaetes from a wide variety of mammals and birds but large mammals do not seem to be infective, so that t icks that feed almost exclusively on large mammals, for example in some agricultural habitats, are rarely infected. The greatest tick infection prevalences occur in deciduous woodland harbouring a diverse mix of host species and the diversity of the different genospecies of B. burgdorferi s.l. is also greatest in such habitats. There is evidence that these genospecies have different host predilections but, apart from the fact that I. persulcatus does not seem to be infected by B. burgdorferi sensu stricto, they do not seem to be adapted to different tick strains or species. © Rapid Science Ltd. 1998     

High levels of multiple metal resistance and its correlation to antibiotic resistance in environmental isolates of Acinetobacter

Forty strains of Acinetobacter were isolated from different environmental sources. All the strains were classified into four genospecies, i.e. A. baumannii (33 isolates), A. calcoaceticus (three isolates), A. junii (three isolates) and A. genospecies3 (one isolate). Susceptibility of these 40 strains to salts of 20 heavy metals and 18 antibiotics was tested by the agar dilution method. All environmental isolates of Acinetobacter were resistant to multiple metal ions (minimum 13 metal ions) while all but one of the strains were resistant to multiple antibiotics (minimum four antibiotics). The maximum number of strains were found to be sensitive to mercury (60% strains) while all strains were resistant to copper, lead, boron and tungsten even at 10 mm concentration. Salts of these four metal ions may be added to the growth medium to facilitate selective isolation of Acinetobacter. Rifampicin and nalidixic acid were the most toxic antibiotics, inhibiting 94.5 and 89.5% of the acinetobacters, respectively. A. genospecies3 was found to be the most resistant species, tolerating high concentrations of all the 20 metal ions and also to a greater number of antibiotics than any other species of Acinetobacter tested. An inhibitory concentration (10 mm) of Ni²⁺ and Zn²⁺ was observed to inhibit the growth of all of the clinical isolates but allowed the growth of the environmental isolates, facilitating the differentiation between pathogenic and non-pathogenic acinetobacters.