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At least 19 recordsLinked to original sources
PubMed1987

Lectin affinity high-performance liquid chromatography. Interactions of N-glycanase-released oligosaccharides with Ricinus communis agglutinin I and Ricinus communis agglutinin II.

The structural determinants required for interaction of oligosaccharides with Ricinus communis agglutinin I (RCAI) and Ricinus communis agglutinin II (RCAII) have been studied by lectin affinity high-performance liquid chromatography (HPLC). Homogeneous oligosaccharides of known structure, purified following release from Asn with N-glycanase and reduction with NaBH4, were tested for their ability to interact with columns of silica-bound RCAI and RCAII. The characteristic elution position obtained for each oligosaccharide was reproducible and correlated with specific structural features. RCAI binds oligosaccharides bearing terminal beta 1,4-linked Gal but not those containing terminal beta 1,4-linked GalNAc. In contrast, RCAII binds structures with either terminal beta 1,4-linked Gal or beta 1,4-linked GalNAc. Both lectins display a greater affinity for structures with terminal beta 1,4-rather than beta 1,3-linked Gal, although RCAII interacts more strongly than RCAI with oligosaccharides containing terminal beta 1,3-linked Gal. Whereas terminal alpha 2,6-linked sialic acid partially inhibits oligosaccharide-RCAI interaction, terminal alpha 2,3-linked sialic acid abolishes interaction with the lectin. In contrast, alpha 2,3- and alpha 2,6-linked sialic acid equally inhibit but do not abolish oligosaccharide interaction with RCAII. RCAI and RCAII discriminate between N-acetyllactosamine-type branches arising from different core Man residues of dibranched complex-type oligosaccharides; RCAI has a preference for the branch attached to the alpha 1,3-linked core Man and RCAII has a preference for the branch attached to the alpha 1,6-linked core Man. RCAII but not RCAI interacts with certain di- and tribranched oligosaccharides devoid of either Gal or GalNAc but bearing terminal GlcNAc, indicating an important role for GlcNAc in RCAII interaction. These findings suggest that N-acetyllactosamine is the primary feature required for oligosaccharide recognition by both RCAI and RCAII but that lectin interaction is strongly modulated by other structural features. Thus, the oligosaccharide specificities of RCAI and RCAII are distinct, depending on many different structural features including terminal sugar moieties, peripheral branching pattern, and sugar linkages.

Carbohydrate Conformation↗
PubMed1976

Structure and toxicity of pure ricinus agglutinin.

Highly purified ricinus agglutinin was found to inhibit protein synthesis in HeLa cells. This effect could be prevented by the addition of the specific antiricinus agglutinin serum, whereas specific anti-ricin serum did not protect the cells, demonstrating that the toxic effect of ricinus agglutinin is not due to contamination with ricin. After reduction of ricinus agglutinin with 2-mercaptoethanol in the presence of 0.5 M galactose the constituent peptide chains were separated by chromatography on a DE-52 column. The B'-chain passed through the column, whereas the A'-chain bound and was eluted with a salt gradient. The B'-chain was further purified by chromatography on a CM-52 column. The shortest chain, the A'-chain, was found to inhibit cell-free protein synthesis whereas the B'-chain did not have this ability. On the other hand, the B'-chain was able to induce agglutination of erythrocytes when tested together with anti-ricinus agglutinin serum indicating that the "b'-chains bind to the cells. Ouchterlony immunodiffusion tests with crude anti-ricin and anti-ricinus agglutinin sera revealed that the two constituent chains of ricinus agglutinin are immunologically partial identical and that they also show reaction or partial identity with both chains of the toxic lectin ricin. The data indicate that a similar structure-function relationship exists in ricinus agglutinin as in ricin. The reason for the much lower toxicity of ricinus agglutinin than of ricin in living animals is discussed.

HeLa Cells↗
PubMed1986

Studies on the antitumor lectins isolated from the seeds of Ricinus communis (castor bean).

Three toxic proteins and one agglutinin were purified from the seeds of Ricinus communis by a simple and fast method using Sepharose 4-B affinity chromatography followed by Sephadex G-100 gel filtration. The weakly adsorbed ricins A and B were retarded and eluted with the buffer from the affinity chromatographic column, while ricin C and ricinus agglutinin had to be eluted with 0.1 M galactose. The molecular weights of ricins A, B, and C were about 62,000 and that of ricinus agglutinin was 120,000, estimated by amino acid compositions and SDS gel electrophoresis. They all possessed two non-identical subunits: A and B chains linked by one disulfide bond. Their LD50 values were 4, 28, 14 and 112 micrograms per kg body weight of mice for ricins A, B and C and ricinus agglutinin, respectively. The amino acid compositions of the three toxins and their A and B subunits were very similar, but not identical, while ricinus agglutinin showed a different composition. Ricin A is a newly isolated lectin which has a strong inhibitory effect on the growth of tumor cells. By using cell cultures, it was demonstrated that the tumor cells were more sensitive to lectin than non-transformed cells, and that this could be caused by the higher binding affinity of lectin to tumor cells than to non-transformed cells.

Amino Acids↗
PubMed1975

Interactions between ricinus agglutinin and human IgM and IgG.

Ricinus agglutinin, purified until homogeneous, precipitates serum glycoproteins with terminal nonreducing galactose residues including IgM and IgG. Almost 100% of IgM reacted with anti-IgM and ricinus agglutinin in quantitative precipitin tests. In similar tests, almost 100% of polyclonal IgG was precipitated by excess anti-IgG, whereas only about 10% reacted with ricinus agglutinin. In quantitative precipitin analyses and affinity chromatography experiments with insolubilized ricinus agglutinin and isolated monoclonal IgG1 and IgG3 proteins, only IgG3 proteins reacted with ricinus agglutinin.

Antibodies, Anti-Idiotypic↗
PubMed1990

Subadult Ixodes ricinus (Acari: Ixodidae) on rodents in Berlin, West Germany.

To identify hosts that may serve as reservoirs for the agent of Lyme disease in Central Europe, we determined whether Ixodes ricinus L. feed most frequently on certain rodents and whether the abundance of these hosts corresponds to the season of feeding activity of the tick in four sites in Berlin, Federal Republic of Germany. In addition, we correlated abundance of I. ricinus with that of particular rodent hosts. Two small rodents were more abundant than any others; a mouse, Apodemus flavicollis, predominated in a wooded site and a vole, Clethrionomys glareolus, in three brush- or grass-covered sites. The tick was most abundant in the mouse-infested site. Although A. flavicollis comprised only about a third of rodents collected, nearly 60% of all such rodent parasitizing I. ricinus fed on this mouse. These ticks were more abundant on mice than voles in each of the study sites and throughout the year, and more larvae fed on these rodents than did nymphs. Although larval as well as nymphal I. ricinus are most abundant during midsummer, they feed on rodents from April through October. Taken together, these observations suggest A. flavicollis as a potentially important reservoir host for I. ricinus-borne infections.

Animals↗
PubMed1992

Tick infection rates with Borrelia: Ixodes ricinus versus Haemaphysalis concinna and Dermacentor reticulatus in two locations in eastern Germany.

Unfed nymphal Ixodes ricinus, Haemaphysalis concinna, and adult Dermacentor reticulatus were collected in two locations of Saxony in July and September 1991 by flagging. In July, the abundance of nymphal I. ricinus was about 2-3 times higher than that of nymphal H. concinna, a time of the year when nymphs of both species are reported to have a seasonal peak of activity. No D. reticulatus were flagged concurrently. In September, host-seeking activity of nymphal I. ricinus was again quite high as was that of adult D. reticulatus but only low numbers of nymphal H. concinna were collected. The flagged ticks were individually examined for Borrelia by an indirect immunofluorescence assay (I. ricinus: n = 414; H. concinna: n = 96; D. reticulatus: n = 116). The prevalence of Borrelia (probably B. burgdorferi) in I. ricinus varied from 12.1% to 21.0%. No borreliae were found in H. concinna. Of the examined D. reticulatus from one site (n = 97) 11.3% contained either B. burgdorferi or a related Borrelia. This may be the first finding of Borrelia in an Eurasian Dermacentor species.

Animals↗
PubMed1990

Gross morphological changes in the salivary glands of Ixodes ricinus (Acari, Ixodidae) between bloodmeals in relation to active uptake of atmospheric water vapour.

The gross morphological changes in the salivary glands of Ixodes ricinus (L.) were investigated at the light microscopic level in various phases off the host with emphasis on the engorged nymph, in order to relate the capability of active vapour uptake in the course of postembryonal development to degeneration and regeneration of salivary-gland alveoli. Agranular alveoli in engorged immatures of I. ricinus, from detachment to the following early pharate phase, do not appear different from those of the unfed instars. This is also true for the female up to approximately the end of oviposition. During moulting, the agranular alveoli of the immatures degenerate and new ones are formed which are apparently already functional in teneral nymphs and adults. In contrast, granular alveoli, much enlarged in freshly detached immature I. ricinus, shrivel in the early post-repletion period and soon reach a highly reduced state which is maintained until apolysis. Subsequently, they disintegrate completely. The finding that engorged and detached immatures of I. ricinus with markedly atrophied granular alveoli are capable of active vapour uptake until some days after initiation of apolysis suggests that only agranular alveoli are responsible for producing the primary secretion involved in vapour uptake.

Animals↗
PubMed1992

Loss of Lyme disease spirochetes from Ixodes ricinus ticks feeding on European blackbirds.

To determine whether blackbirds (Turdus merula), the most abundant and most abundantly tick-infested ecotonal bird of Central Europe, may contribute to the transmission of the Lyme disease spirochete (Borrelia burgdorferi), we compared the infectivity to ticks of naturally as well as experimentally infected blackbirds and rodents. European blackbirds experience intense exposure to Ixodes ricinus ticks and to the pathogens that they transmit. In nature, subadult I. ricinus ticks found feeding on these birds generally contain no spirochetes, although infection is universal in those found on black-striped mice (Apodemus agrarius). Those found on yellow-necked mice (A. flavicollis) are less frequently infected. Ticks lose infection in the course of feeding on blackbirds and fail to infect them. Subadult I. ricinus ticks readily feed on blackbirds, black-striped mice, and jirds (Meriones unguiculatus), but engorge less fully on the bird than on the rodents. Although birds may burden human health by establishing new infestations of I. ricinus ticks, our observations indicate that particular birds may benefit health by locally diminishing transmission of the Lyme disease spirochete.

Animals↗
PubMed1991

Hosts on which nymphal Ixodes ricinus most abundantly feed.

To identify hosts that may serve as European reservoirs for the agent of Lyme disease, Borrelia burgdorferi, we determined whether nymphal Ixodes ricinus feed mainly on particular mice (Apodemus flavicollis or A. agrarius), voles (Clethrionomys glareolus) or on sand lizards (Lacerta agilis) and whether the abundance of these hosts corresponds to the seasonal activity of the subadult stages of the vector tick. In all sites, the mice appeared most heavily infested by larvae; at least seven parasitized each mouse, about three per vole and four per lizard. Many fewer nymphal I. ricinus parasitized A. flavicollis and C. glareolus than did larvae. Although more than 30 times as many larval than nymphal ticks parasitized the two most abundant hosts (C. glareolus and A. flavicollis), about 15 times as many fed on A. agrarius and twice as many on lizards. Nymphal and larval ticks fed on rodents at about the same time. Lizards were most abundantly parasitized by nymphs somewhat earlier than by larvae. Early in the season of transmission of Lyme disease, virtually all A. agrarius as well as lizards were potentially exposed to spirochetes borne by nymphal I. ricinus. We concluded that larval and nymphal I. ricinus differentially parasitize different hosts. Because so many of these nymphs feed on them, A. agrarius may more effectively serve as reservoirs for the agent of Lyme disease than do other putative reservoir hosts. The presence of lizards may inhibit transmission.

Animals↗
PubMedDate not supplied

[Experience in the study of the peculiarities of the distribution of the tick Ixodes ricinus in a large territory].

Attempts were undertaken to study the character of the distribution of I. ricinus over a large territory. Methodic principles of the land survey of arthropods distribution and laboratory processing of its results, that were used before for I. persulcatus, were found to be quite suitable for I. ricinus. It was established that hungry adults of I. ricinus have at least three types of the distribution throughout the forests of Lithuania. Types of the distribution can be ascertained by the results of the record of I. ricinus nymphs with a flag.

Animals↗
PubMedDate not supplied

[Study of characteristics of distribution of the tick Ixodes ricinus over a large territory].

Attempts were undertaken to study the character of the distribution of I. ricinus over a large territory. Methodic principles of the land survey of arthropods distribution and laboratory processing of its results, that were used before for I. persulcatus, were found to be quite suitable for I. ricinus. It was established that hungry adults of I. ricinus have at least three types of the distribution throughout the forests of Lithuania. Types of the distribution can be ascertained by the results of the record of I. ricinus nymphs with a flag.

Animals↗
PubMed1979

[New aspects of the part of the vector played by Ixodes ricinus L. in Switzerland. Preliminary note (author's transl)].

The authors, after having recalled their recent work on Ixodes ricinus ecology, give the new results about the part played by this species in the transmission of different infectious agents in Switzerland. I. ricinus was already known to be the most important vector of the tick borne encephalitis virus, and of protozoans of the Babesia genus. In this article, we describe the existence in the hemolymphe of different I. ricinus populations, of a rickettsia species related to the RMST group (Rocky-Mountain Spotted Fever), of a trypanosome, which is close to T. theileri, and of an infectious larval form (L3) of Dipetalonema rugosicauda. An outline is suggested with the object of illustrating the functioning of a natural foci of tick encephalitis. The biological significance of the unusual presence of trypanosomes and of larval filariae in ticks is also discussed. The authors underline the fact that rickettsia, trypanosomes and filarial forms are observed for the first time in Swiss I. ricinus.

Animals↗
PubMed1986

Studies on Ricinus communis lectin--carbohydrate interaction by means of affinity electrophoresis.

The affinity gel electrophoresis of lectins purified from the seeds of Ricinus communis was studied. The mobilities of lectins on the gel showed various degree of retardation with their affinity toward their macromolecular ligand-agarose. Ricinus agglutinin which possessed the strongest affinity was retarded strongly, ricin C, and ricin B moderately, and ricin A, weakly. The concentrations of free moving ligand-galactose to reduce the retardation were also correlated very well with the potencies of affinities of lectins toward the ligand. The Kd values calculated from the retardations were 4.32 microM, 18.32 microM, 28.13 microM and 52.88 microM for ricinus agglutinin, ricin C, ricin B and ricin A respectively. Affinity gel electrophoresis was found to be a simple and quick method for studying the interaction of lectins with their ligands.

Carbohydrates↗
PubMed1979

Effect of sulfhydryl reagents and protease inhibitors on sodium dodecyl sulfate-heat induced dissociation of Ricinus communis agglutinin.

Ricinus communis agglutinin dissociated to lower molecular weight forms when heated in sodium dodecyl sulfate in the absence of reducing agents, while ricin was little affected by such treatment. The data suggest that strong noncovalent bonds hold together two A-B heterodimers in the Ricinus communis agglutinin tetramer. Protease inhibitors such as diisopropylfluorophosphate, phenylmethansefulonyl fluoride, and EDTA, did not prevent the sodium dodecyl sulfate-heat induced dissociation; however, sulfhydryl specific reagents (N-ethylmaleimide, 5,5'-dithiobis (2-nitrobenzoic acid) and p-chloromercuribenzoate) were effective. Titration of the lectins in sodium dodecyl sulfate indicated that ricin contains one sulfhydryl and Ricinus communis agglutinin four sulfhydryl groups, none of which react in the presence of 8 M urea. The sulfhydryl groups that could be titrated in the intact proteins in sodium dodecyl sulfate were on the A chains.

Lectins↗
PubMed1992

Biological activity of recombinant Ricinus communis agglutinin A chain produced in Escherichia coli.

DNA encoding Ricinus communis agglutinin A chain was ligated into the E. coli expression vector pDS 5/3. Induced E. coli 71.18 cells which had been transformed with this plasmid express Ricinus communis agglutinin A chain in a soluble and biologically active form. Recombinant Ricinus communis agglutinin A chain had ribosomal RNA N-glycosidase activity and was approximately 10-fold less active than ricin A chain in a cell-free protein synthesis inhibition assay.

Cell-Free System↗
PubMed1989

Repetitive detection by immunoblotting of an integumental 25-kDa antigen in Ixodes ricinus and a corresponding 20-kDa antigen in Rhipicephalus appendiculatus with sera of pluriinfested mice and rabbits.

Mice were pluriinfested with nymphs and rabbits, with adult Ixodes ricinus. As determined by immunoblotting, greater than 50% of sera from these animals reacted against a tick antigen with a molecular weight of 25 kDa, which was detected in total extracts of partially fed I. ricinus females and in tick integumental extract. It was also found in engorged nymphs but was absent from larvae. Sera of I. ricinus-infested rabbits and mice or of rabbits infested with Rhipicephalus appendiculatus adults reacted with a 20-kDa antigen in total extracts of partially fed R. appendiculatus females and the integument of this species.

Animals↗
PubMed1979

Passive transfer of resistance in rabbits infested with adult Ixodes ricinus L: humoral factors influence feeding and egg laying.

Parital immunity against the bites of female I. ricinus was transferred to normal rabbits by inoculating immune serum from resistant animals. Transferred humoral factors diminished the weight of the ticks' blood meal by 29% and increased the feeding period by about 1 day in comparison with ectoparasites engorged on controls. They provoked also the failure of egg laying by female I. ricinus. Only 55% of ticks fed on treated rabbits laid eggs (94% on controls). The immunological state of immune serum donors or recipients was studied and the IgG and homocytotropic specific anti-I. ricinus antibodies were identified. The immediate hypersensitivity of rabbits' skin was also controlled.

Animals↗