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1
Abe, R., J. J. Ryan, and R. J. Hodes. "Mls is not a single gene, allelic system. Different stimulatory Mls determinants are the products of at least two nonallelic, unlinked genes." Journal of Experimental Medicine 166, no. 4 (October 1, 1987): 1150–55. http://dx.doi.org/10.1084/jem.166.4.1150.
Full textAbstract:
Mls determinants share with MHC products the unique property of stimulating T cells at extraordinarily high precursor frequencies. The Mls system was originally described as a single locus on chromosome 1, with four alleles, Mlsa, Mlsb, Mlsc, and Mlsd, that encode polymorphic cell surface structures. However, the fundamental issues of polymorphism and allelism in the Mls system remain controversial. To clarify these questions, a formal segregation analysis of the genes encoding Mlsa and Mlsc determinants was carried out by testing the capacity of spleen cells from progeny of (Mlsa X Mlsc)F1 X Mlsb breedings to stimulate responses by unprimed T cells and by Mlsa- and Mlsc-specific cloned T cells. The results of this analysis indicated that the gene encoding Mlsa determinants is neither allelic to nor linked to the gene encoding Mlsc determinants. Together with previous findings, these results also suggest that another strongly stimulatory type, Mlsd, in fact results from the independent expression of unlinked Mlsa and Mlsc gene products. Based on these observations, it is concluded that, contrary to conventional concepts, the stimulatory phenotypes designated as Mlsa, Mlsc, and Mlsd can be accounted for by the independent expression of the products of at least two unlinked gene loci.
2
Ryan, J. J., J. J. Mond, and F. D. Finkelman. "The Mlsd-defined primary mixed lymphocyte reaction: a composite response to Mlsa and Mlsc determinants." Journal of Immunology 138, no. 12 (June 15, 1987): 4085–92. http://dx.doi.org/10.4049/jimmunol.138.12.4085.
Full textAbstract:
Abstract Considerable disagreement exists among immunologists regarding the polymorphic nature of the murine Mls system. An estimate of the capacity of a given putative Mls allelic gene product expressed on a stimulator population to elicit proliferation of H-2-compatible Mls-disparate unprimed T cells may vary widely among different groups of investigators. This laboratory has shown previously that preactivation of B lymphocytes in a splenocyte stimulator population by exposure to goat anti-mouse IgD (GaMD) before irradiation dramatically enhanced the in vitro presentation not only of the strongly stimulatory (and highly cross-reactive) Mlsa and Mlsd, but also the more poorly stimulatory Mlsc specificity. Therefore, by the use of GaMD-treated splenocytes that optimally present the various Mls non-H-2 stimulatory epitopes, we attempted in this study to obtain a clearer understanding of Mls polymorphism by re-examining the conflicting claims associated with the mixed lymphocyte reaction (MLR) stimulatory capacity of different Mls specificities. Among H-2k responder cells of the Mls null, Mlsa, Mlsb, or Mlsd genotypes, only T cells from Mlsd-bearing CBA/J mice did not respond to Mlsc determinants present on GaMD-treated C3H/HeJ stimulator cells. Crossing CBA/J with an Mlsc-responsive mouse strain yielded an F1 animal in which nonresponsiveness to Mlsc was dominant. Although Mlsa (AKR/J) and Mlsc (C3H/HeJ) parental T cells both proliferated vigorously to Mlsd (CBA/J) stimulator cells, the Mlsa/c (AKR X C3H)F1 T cells responded poorly to GaMD-treated Mlsd stimulator cells. In addition, Mlsd (CBA/J) T cells were nonresponsive to Mlsa (AKR/J), Mlsc (C3H/HeJ), and Mlsa/c (AKR X C3H)F1 GaMD-treated stimulator cells. Because Mlsa (AKR/J) and Mlsc (C3H/HeJ) specificities are mutually stimulatory, at least limited polymorphism must exist in the Mls system. However, because Mlsa/c (AKR X C3H) and Mlsd (CBA/J) specificities are mutually nonstimulatory, T cell proliferation in an Mlsd-defined primary MLR is most likely due to a composite response to Mlsa and Mlsc epitopes present on CBA/J stimulator cells.
3
Abe, R., J. J. Ryan, and R. J. Hodes. "Clonal analysis of the Mls system. A reappraisal of polymorphism and allelism among Mlsa, Mlsc, and Mlsd." Journal of Experimental Medicine 165, no. 4 (April 1, 1987): 1113–29. http://dx.doi.org/10.1084/jem.165.4.1113.
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Only two sets of antigenic determinants are recognized by T lymphocytes at uniquely high precursor frequencies: those encoded by the MHC and those encoded by Mls. The structural as well as functional characteristics of MHC products have been extensively analyzed. In contrast, little information concerning the nature of Mls genes or their products is available. Although it was originally described (5, 6) that the Mls locus on chromosome 1 is composed of four alleles that encode polymorphic cell surface structures, the issues of polymorphism and allelism in the Mls system have been controversial for some time. In the present study, T cell clones were generated by continuous stimulation of B10.BR (H-2k, Mlsb) T cells by CBA/J (H-2k, Mlsd) stimulators and they were used to analyze the relationship of putative Mlsa, Mlsc, and Mlsd determinants. All clones proliferated in response to determinants expressed by CBA/J stimulators. In addition, each of these clones exhibited a second reactivity to either AKR/J (H-2k, Mlsa) or C3H/HeJ (H-2k, Mlsc) stimulators. No clone responded to both AKR/J and C3H/HeJ. These second specificities were defined to be for Mlsa or Mlsc determinants, respectively, by the response patterns of clones and unprimed T cells to stimulators derived from congenic strains, recombinant inbred (RI) strains, and backcross mice. Moreover, a segregation analysis of the (CBA/J X B10.BR)F1 X B10.BR backcross indicated that the Mlsa-like and Mlsc-like determinants expressed on CBA/J (Mlsd) cells are in fact encoded by nonallelic, unlinked genes. These findings suggest a new concept of the polymorphism and genetics of the Mls system. It is proposed that two distinct and nonallelic gene products express, respectively, the noncrossreacting Mlsa and Mlsc determinants, and that the Mlsd phenotype does not represent an independent genotype but rather reflects the concurrent expression of Mlsa and Mlsc. The Mls system, therefore, consists of at least two systems that are distinct both genetically and antigenically, and that may be of different biologic or physiologic significance as well.
4
Abe, R., J. J. Ryan, F. D. Finkelman, and R. J. Hodes. "T cell recognition of Mls. T cell clones demonstrate polymorphism between Mlsa, Mlsc, and Mlsd." Journal of Immunology 138, no. 2 (January 15, 1987): 373–79. http://dx.doi.org/10.4049/jimmunol.138.2.373.
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Abstract The determinants encoded by the minor lymphocyte stimulating locus (Mls) are defined as determinants that induce strong T cell proliferative responses in primary mixed lymphocyte reactions. Although the Mls locus was originally described as having four alleles, a, b, c, and d, a number of recent observations have led several investigators to challenge the idea that Mls is truly a polymorphic system. To better define this system of determinants recognized at high frequency by T cells, the present studies were undertaken to evaluate the polymorphism of Mls products. In the present study, the in vitro proliferative responses of Mlsa- and Mlsc-specific T cell clones were employed to analyze Mls products. The identification of determinants recognized by Mlsa- and Mlsc-reactive clones was established by the pattern of responses to stimulators derived from congenic strains, recombinant inbred strains, and backcross mice. T cell clones and unprimed T cells gave concordant responses that confirmed the Mlsa or Mlsc specificity of the cloned populations. With the use of these two sets of Mls-specific T cell clones, the existence or absence of polymorphism of Mls-encoded gene products was examined. It was found that Mlsa-specific cloned T cells responded to Mlsa but not Mlsc stimulators, whereas Mlsc-specific clones responded to Mlsc but not Mlsa. This reciprocal pattern of specificity indicates that the Mls system as currently defined is therefore truly polymorphic. In addition, it was observed that both Mlsa- and Mlsc-specific clones were stimulated by Mlsd stimulators. In particular, the possibility that Mlsa and Mlsc are not alleles but products of different loci and that Mlsd strains are those that express both Mlsa and Mlsc is considered.
5
Click, R. E., A. M. Adelmann, and M. M. Azar. "Immune responses in vitro. XIII. MLR detectability of Mlsa-, Mlsb-, Mlsc-, and Mlsd-encoded products." Journal of Immunology 134, no. 5 (May 1, 1985): 2948–52. http://dx.doi.org/10.4049/jimmunol.134.5.2948.
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Abstract The Mls locus was originally defined to have four alleles; all controlled products that were detectable in MLR except b, which was described as being null. More recent evidence led other investigators to postulate that the Mls locus is nonpolymorphic, being composed of only the b null allele and a singly expressed allele previously ascribed to be the a and d alleles. Our results indicate that Mlsa and Mlsd control products that are antigenically distinct and, therefore, the products cannot be controlled by the same allele. In addition, the product of Mlsb was easily detectable by Mlsa and Mlsd responding cells and cannot be considered null. Alternative explanations are considered for these conflicting results.
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DeKruyff, R. H., S. T. Ju, J. Laning, H. Cantor, and M. E. Dorf. "Activation requirements of cloned inducer T cells. III. Need for two stimulator cells in the response of a cloned line to Mls determinants." Journal of Immunology 137, no. 4 (August 15, 1986): 1109–14. http://dx.doi.org/10.4049/jimmunol.137.4.1109.
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Abstract To gain insight into the nature of Mls determinants, we examined the stimulator cells responsible for the activation of inducer T cell clones by Mls determinants. Two types of clones responding to Mls determinants were identified. One type responded to purified B cells, but not to splenic adherent cells (SAC), from mice bearing Mls stimulatory determinants. The other type of Mls-reactive T cell clone, including the representative clone Ly1-N5, demonstrated a vigorous response to unfractionated spleen cells, but showed little or no response to B cells alone or to SAC alone from mice bearing the Mlsa or Mlsd stimulatory determinant. The response of these clones to Mls determinants required stimulation by two cell types. The failure of clone Ly1-N5 to respond to Mlsa-bearing B cells was reversed by the addition of SAC taken from mice bearing the Mlsa allele. In addition, SAC from mice bearing the nonstimulatory Mlsb allele could synergize with B cells from Mlsa-bearing animals. B cells were required to provide the Mlsa determinant, because the combination of Mlsa-bearing SAC and Mlsb-bearing B cells did not activate the clone. The response of clone Ly1-N5 to Mls is restricted by Ia determinants (shared by H-2b, H-2d, and H-2k haplotypes but not by the H-2q haplotype). The permissive H-2 alleles can be present either on the stimulator B cell or on the SAC. The optimal response of the clone was obtained by using B cells bearing Mlsa and the permissive Ia epitopes. However, a significant response of the clone to B cells bearing Mlsa but an inappropriate Ia (Iaq) was also seen in the presence of SAC bearing the nonstimulatory Mlsb allele but the permissive Ia epitopes.
7
Speiser, D. E., R. Schneider, H. Hengartner, H. R. MacDonald, and R. M. Zinkernagel. "Clonal deletion of self-reactive T cells in irradiation bone marrow chimeras and neonatally tolerant mice. Evidence for intercellular transfer of Mlsa." Journal of Experimental Medicine 170, no. 2 (August 1, 1989): 595–600. http://dx.doi.org/10.1084/jem.170.2.595.
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Tolerance to Mlsa has been shown to be associated with clonal deletion of cells carrying TCR beta chain variable regions V beta 6 or V beta 8.1 in mice possessing I-E antigens. To evaluate the rules of tolerance induction to Mlsa we prepared irradiation bone marrow chimeras expressing Mlsa or Mlsb and I-E by different cell types. Deletion of V beta 6+, Mlsa-reactive T cells required the presence of Mlsa and I-E products either on bone marrow-derived cells or on irradiated recipient cells. Tolerance was induced when Mlsa and I-E were expressed by distinct cells of the chimera. Also neonatally tolerized mice exhibited depletion of V beta 6+ cells after injection of I-E- Mlsa spleen cells (DBA/1) into newborn I-E+ Mlsb mice (BALB/c x B10.G)F1. These results suggest that the product of the Mlsa locus is soluble and/or may be transferred from cell to cell and bound to I-E antigens. The chimera experiments also showed that tolerance to Mlsa is H-2 allele independent, i.e., is apparently unrestricted. Differentiation of chimeric (H-2d/Mlsa x H-2q/Mlsb)F1 stem cells in either an H-2d or an H-2q thymus revealed that tolerance assessed by absence of V beta 6+ T cells is not dependent on the thymically determined restriction specificity of T cells.
8
Click, R. E., G. Cahill, D. Schneider, A. Adelmann, M. M. Azar, J. J. Tarquinio, and A. B. Peck. "Nonresponsiveness to Mlsd in F1 hybrid mice carrying Mlsa and Mlsc genes." Journal of Immunology 139, no. 2 (July 15, 1987): 321–25. http://dx.doi.org/10.4049/jimmunol.139.2.321.
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Abstract Neither the biological function nor a basic understanding of the enigmatic chromosome 1-encoded Mls locus of the mouse has yet been uncovered despite extensive investigations. The present report is a continuation of our genetic analyses of the Mls locus in an attempt to better define the system. Data presented here indicate that in contrast to cells of mice expressing either the Mlsa or Mlsc allele which respond in mixed leukocyte reactions to cells expressing the Mlsd allelic products, cells from (Mlsa X Mlsc)F1-hybrid mice do not. In addition, the nonresponder phenotype appears to segregate as a single autosomal genetic system in backcross animals. These findings fail to support two recently advanced hypotheses: first, that the Mls locus is nonpolymorphic, or second, that the Mls locus controls differential expression of Ia antigenic determinants. Although the mechanism by which a (responder X responder) converts to a nonresponder remains unknown, three models involving gene complementation are discussed.
9
Hämmerling, U., M. Toulon, M. Chun, S. Palfree, and M. K. Hoffmann. "Bidirectionality of mixed lymphocyte stimulation (Mls) response. Effects of Mlsb stimulator cells on Mlsa helper cells." Journal of Immunology 140, no. 8 (April 15, 1988): 2543–48. http://dx.doi.org/10.4049/jimmunol.140.8.2543.
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Abstract The activation of BALB/c lymphocytes in the mixed lymphocyte reaction to Mls-disparate APC has been shown to encompass up to 20% of the mature resting helper T lymphocyte population. In addition to these overtly Mls-responsive cells, our studies have revealed a second population that respond to the Mls difference of DBA/2 spleen cells in conjunction with the mitogen Con A. This part of the Mls response is therefore latent. As mitogen and Mls-stimulating effect act in synergy, it is likely that both stimuli act on the same cell, and hence the Mls effect can be regarded as a regulatory interaction between APC and Th cell. By use of congenic BALB.Mlsa mice, the regulatory effect has been mapped to the Mls locus. The regulatory influence has also been demonstrated in DBA/2 Th cells (Mlsa) stimulated simultaneously with mitogen and Mls-disparate (Mlsb) APC, consistently causing inhibition of mitogen-induced proliferation in this reverse Mls direction. This antagonistic effect has also been linked to the Mls locus. We conclude that the Mls reaction governed by the a and b alleles is bidirectional, producing synergy with class II-dependent activation signals in the direction of Mlsa----Mlsb, and antagonism in the direction Mlsb----Mlsa. Both the classical Mls and the reverse Mls effects have been demonstrated at the clonal level. These results are in accord with the previously proposed hypothesis that the Mls molecule serves as a down-regulatory stimulus in the activation of Th cells. Mls responses of Mlsb T cells are explained as the consequence of a diminished down-regulation by Mlsa APC. Conversely, the reverse Mls response described here can be considered a consequence of inordinately high down-regulation of the Mlsa T cell responses by Mlsb APC.
10
Ryan, J. J., H. B. LeJeune, J. J. Mond, and F. D. Finkelman. "Genetic analysis of the presentation of minor lymphocyte-stimulating determinants. II. Differing non-MHC control of super-stimulatory and more poorly stimulatory Mls phenotypes." Journal of Immunology 144, no. 7 (April 1, 1990): 2506–17. http://dx.doi.org/10.4049/jimmunol.144.7.2506.
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Abstract Analysis of the capacity of splenocytes from non-prototypic Mlsa or Mlsc mouse strains to stimulate allogeneic H-2k-compatible T cells in a primary Mls-defined MLR provided interesting examples of exceptions to the usually stated characterization of Mlsa and Mlsc determinants as highly stimulatory of weakly stimulatory, respectively. Across the Mlsa barrier, MA/My stimulator cells had a significantly reduced capacity to elicit responder proliferation in comparison with prototypic AKR/J or less well studied C58/J, CE/J, or RF/J splenocytes. Across the Mlsc barrier, a gradient of stimulatory ability was observed with RF/J splenocytes being virtually nonstimulatory, prototypic C3H/HeJ splenocytes having an intermediate capacity, and CE/J and C58/J being highly stimulatory presenters of this non-MHC specificity. The differing capacity of each of these H-2k stimulator cells to elicit unprimed responder cell proliferation across an Mlsa or Mlsc difference correlated with the T cell growth factor activity that was secreted into the MLR supernatants. The super stimulatory form of Mlsc was expressed in an autosomal dominant fashion by (Mlsc poorly stimulatory x Mlsc super-stimulatory)F1 animals, (BALB.K x C58/J)F1 or (RF/J x CE/J)F1. The segregation of Mlsc stimulatory ability among first backcross and F2 animals derived from the former F1 was compatible with a single non-MHC gene controlling the expression and presentation of the super-stimulatory form of Mlsc. The regulatory nature of this gene was indicated by the observation that F1 animals generated from the Mlsc nonprototypic and poorly stimulatory BALB/c parental strain were self-tolerant to the super-stimulatory form of Mlsc. The existence of an Mls specificity other than a and c was suggested by positive non-MHC MLR responses in certain responder/stimulator cell combinations of Mls prototypic and nonprototypic mouse strains.
11
Needleman, B. W., D. H. Lynch, and R. J. Hodes. "Effect of Mlsa on antigen presentation to class II-restricted T cells." Journal of Immunology 141, no. 11 (December 1, 1988): 3760–67. http://dx.doi.org/10.4049/jimmunol.141.11.3760.
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Abstract The nature of the gene products encoded or regulated by the minor lymphocyte-stimulating (Mls) loci remains enigmatic despite extensive experimental evaluation. This work tested the hypothesis that the Mlsa genotype, when compared to the Mlsb genotype, facilitates Ag presentation to class II-restricted T cells. Titrated numbers of H-2-identical, Mls-disparate APC were used to stimulate proliferation of autoreactive, alloreactive, or Ag-specific class II-restricted T cell clones or lines. Apparent preferential presentation by Mlsa vs Mlsb APC obtained from H-2-identical strains was seen infrequently, and when observed, analysis with the use of APC from recombinant inbred lines revealed that preferential presentation did not correlate with the Mls genotype of the APC. These studies show that the Mlsa genotype does not influence overall Ag presentation to class II-restricted T cells.
12
Janeway, C. A., and M. E. Katz. "The immunobiology of the T cell response to Mls-locus-disparate stimulator cells. I. Unidirectionality, new strain combinations, and the role of Ia antigens." Journal of Immunology 134, no. 4 (April 1, 1985): 2057–63. http://dx.doi.org/10.4049/jimmunol.134.4.2057.
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Abstract The primary mixed lymphocyte reaction of T cells to Mls-locus-disparate stimulator cells differs from that to non-self Ia antigens in several respects. In the present experiments, the unidirectional nature of this response is shown in several strain combinations, including the newly detected Mlsa and Mlsa-like alleles expressed by strains PL/J, RF/J, and SM/J. All of these strains stimulate MHC-identical T cells strongly. In addition, they stimulate a variety of cloned T cell lines specific for Mlsa,d, which can thus be shown to respond to Mlsa,d stimulators of the H-2b,d,k,u, and v haplotypes. Although these results suggest that primary T cell responses to Mlsa,d are unlikely to be MHC restricted, these primary responses are readily inhibited by monoclonal antibodies specific for the I-A and especially the I-E products borne by the stimulator cells, as well as by monoclonal antibodies specific for L3T4a on the responding T cells. This effect of anti-Ia antibodies is not overcome by exogenous interleukin 1. Thus, I-A and especially I-E molecules are centrally involved in the unidirectional primary T cell response to the potently stimulating Mlsa and Mlsd alleles expressed by cells of several different MHC haplotypes.
13
Abromson-Leeman, S. R., J. C. Laning, and M. E. Dorf. "T cell recognition of Mlsc,x determinants." Journal of Immunology 140, no. 6 (March 15, 1988): 1726–31. http://dx.doi.org/10.4049/jimmunol.140.6.1726.
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Abstract Among a large number of cow insulin-specific T cell clones derived from both C57BL/10 and B10.A strains, several were found to react to non-MHC-linked gene products of a number of allogeneic strains. The stimulatory moiety for three of these clones correlates, in part, with expression of Mlsc, as defined by mouse strains C3H/HeJ and A/J. In addition, all three of these clones are stimulated by cells from strain PL/J, which has the poorly defined Mlsx allele. The data strongly suggest that Mlsx may, in fact, be Mlsc or is, at least, highly cross-reactive with Mlsc. Segregation analysis by using (B10.D2 X PL/J)F2 mice demonstrates that the Mlsx gene is genetically independent of the Mlsa linked Ly-9 marker on chromosome 1. Further studies with the use of these Mlsc,x-reactive clones reveal that they also recognize a gene product present in many mouse strains including DBA/2 which were previously phenotyped as Mlsa. However, testing of BxD recombinant inbred lines excludes Mlsa as being the stimulatory moiety. We therefore propose reclassification of the Mls phenotypes of several mouse strains based upon a two-locus model for Mls.
14
Vacchio, M. S., O. Kanagawa, K. Tomonari, and R. J. Hodes. "Influence of T cell receptor V alpha expression on Mlsa superantigen-specific T cell responses." Journal of Experimental Medicine 175, no. 5 (May 1, 1992): 1405–8. http://dx.doi.org/10.1084/jem.175.5.1405.
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Recognition of conventional foreign antigen by T cells is determined by the expression of multiple variable regions of both alpha and beta chains of the T cell receptor (TCR) alpha/beta heterodimer. In contrast, there exists a class of antigens that appears to interact with the TCR alpha/beta heterodimer through the variable region on the beta chain (V beta), independent of other TCR components, a property that has led to their designation as superantigens. The goal of the present study was to analyze V alpha use in V beta 6+ T cells responsive to the superantigen, Mlaa. Results indicate that while deletion of T cells expressing V beta 6 in Mlsa-expressing mice is essentially complete and therefore appears to occur regardless of V alpha usage, in vitro Mlsa stimulation of T cells from Mlsa-negative mice results in significant skewing of V alpha use among responding V beta 6+ T cells. This indicates that V alpha expression influences recognition of the superantigen, Mlsa by mature peripheral T cells.
15
Schneider, R., R. K. Lees, T. Pedrazzini, R. M. Zinkernagel, H. Hengartner, and H. R. MacDonald. "Postnatal disappearance of self-reactive (V beta 6+) cells from the thymus of Mlsa mice. Implications for T cell development and autoimmunity." Journal of Experimental Medicine 169, no. 6 (June 1, 1989): 2149–58. http://dx.doi.org/10.1084/jem.169.6.2149.
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The postnatal ontogeny of potentially autoreactive T cells has been studied in a model system where a particular TCR beta chain variable domain (V beta 6) is correlated with reactivity to a minor antigen encoded by the Mlsa locus. Although absent among mature (CD4+ or CD8+) T cells in adult mice expressing Mlsa, brightly staining V beta 6+ cells were readily detectable in the thymus of neonatal animals, reaching a maximum after 4 d and decreasing rapidly thereafter. These V beta 6+ thymocytes were predominantly of the CD4+ phenotype and were localized in the medulla of the developing thymus. Furthermore, the intensity of TCR expression by these CD4+ cells was significantly (twofold) reduced as compared with age-matched Mlsb controls. A rapid disappearance of CD4+V beta 6+ cells (and corresponding decrease in TCR density) could also be observed in the thymus of Mlsb mice that had been injected neonatally with Mlsa spleen cells. Taken together, these results raise the possibility that some autoreactive T cells may persist after birth and that TCR downregulation may occur as a physiological response to tolerogenic signals in vivo.
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MacDonald, H. R., T. Pedrazzini, R. Schneider, J. A. Louis, R. M. Zinkernagel, and H. Hengartner. "Intrathymic elimination of Mlsa-reactive (V beta 6+) cells during neonatal tolerance induction to Mlsa-encoded antigens." Journal of Experimental Medicine 167, no. 6 (June 1, 1988): 2005–10. http://dx.doi.org/10.1084/jem.167.6.2005.
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The cellular basis of neonatally induced T cell tolerance has been investigated in a model system in which usage of a particular TCR V beta segment (V beta 6) is strongly correlated with reactivity to antigens encoded by the Mlsa genetic locus. Expression of V beta 6 by peripheral T cells was virtually abolished in BALB/c (H-2d, Mlsb) mice rendered neonatally tolerant to DBA/2 (H-2d, Mlsa) lymphoid cells, whereas control V beta 8-bearing T cells remained at near normal levels. Further analysis revealed that elimination of V beta 6+ T cells occurred in the thymus of neonatally tolerant mice and could not be explained by receptor modulation or T cell chimerism. These data thus support the clonal deletion model of tolerance induction.
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Molina, I. J., N. A. Cannon, R. Hyman, and B. T. Huber. "Macrophages and T cells do not express Mlsa determinants." Journal of Immunology 143, no. 1 (July 1, 1989): 39–44. http://dx.doi.org/10.4049/jimmunol.143.1.39.
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Abstract In order to test the tissue distribution of Mlsa determinants, we have generated highly purified stimulator cell populations. First, Mlsa expression in bone marrow derived macrophages (M phi) of Mlsa genotype was tested in primary MLR and on Mlsa-specific T cell hybridomas (THy). Second, a similar experimental approach was used to analyze thioglycolate, peptone or Con A elicited peritoneal M phi. In all cases, these M phi cell populations were able to generate an excellent alloresponse, whereas no functional Mlsa determinants could be detected. Third, to further investigate whether the expression of Mlsa is lymphocyte specific, but dependent on expression of class II molecules, we have transfected I-Ek alpha and beta cDNA into a panel of thymomas of Mlsa genotype. Although we achieved a high level of surface I-Ek expression in all of these T cell tumors, none of them was able to trigger the Mlsa-specific THy. These results strongly suggest that Mlsa expression is limited to B cells. It is likely that Mlsa is a tissue-specific self-peptide that associates with class II molecules.
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Webb, S. R., A. Okamoto, Y. Ron, and J. Sprent. "Restricted tissue distribution of Mlsa determinants. Stimulation of Mlsa-reactive T cells by B cells but not by dendritic cells or macrophages." Journal of Experimental Medicine 169, no. 1 (January 1, 1989): 1–12. http://dx.doi.org/10.1084/jem.169.1.1.
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Evidence was sought on the tissue distribution of Mlsa determinants, a class of cell-associated non-H-2 alloantigens that is highly immunogenic for unprimed T cells. Whereas normal CD4+ T cells and an Mlsa-reactive T hybridoma gave strong responses to Mlsa-positive stimulator populations containing Ig+ B cells, anti-Mlsa responses to B-depleted stimulators were almost undetectable. The B-depleted stimulators tested included Thy-1- spleen cells from mu-suppressed mice (mice treated with anti-mu antibody from birth) and J11d- preparations of spleen dendritic cells (DC) and peritoneal macrophages (M phi) from normal mice. Each of these populations was strongly immunogenic for allo-H-2-reactive T cells. The failure to detect Mlsa determinants on Ig- APC, i.e., M phi and DC, suggests that Mlsa determinants are not typical H-2-associated peptides. The data are more compatible with a model in which Mlsa determinants represent (or form part of) an integral cell membrane molecule expressed largely, and perhaps exclusively, on B cells. T cells might recognize these molecules only in native form, "processed" Mlsa determinants being nonimmunogenic. Consistent with this possibility, no evidence was found that Mlsa-negative B cells could absorb Mlsa determinants from Mlsa-positive B cells in a chimeric environment.
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Mountz, J. D., T. M. Smith, and K. S. Toth. "Altered expression of self-reactive T cell receptor V beta regions in autoimmune mice." Journal of Immunology 144, no. 6 (March 15, 1990): 2159–66. http://dx.doi.org/10.4049/jimmunol.144.6.2159.
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Abstract Intrathymic tolerance results in elimination of T cells bearing self-reactive TCR V beta regions in mice expressing certain combinations of I-E and minor lymphocyte stimulatory (Mls) phenotypes. To determine if autoimmune strains of mice have a defect in intrathymic deletion of self-reactive TCR V beta regions, expression of V beta 3, V beta 6, V beta 8.1, and V beta 11 were examined in lpr/lpr and +/+ strains of mice; MRL/MpJ(H-2K, I-E+, Mlsb,), C57BL/6J(H-2b, I-E-, Mlsb,), C3H/HeJ(H-2k, I-E+, Mlsc), AKR/J(H-2k, I-E+, Mlsa); and in autoimmune NZB/N(H-2d, I-E+, Mlsa) and BXSB(H-2b, I-E-, Mlsb) mice. The results suggest that, during intrathymic development, self-reactive T cells are deleted in autoimmune strains of mice as found in normal control strains of mice. However, the TCR V beta repertoire is skewed in autoimmune strains compared to normal strains of mice. For example, MRL-lpr/lpr mice, but not other lpr/lpr strains, had increased expression of V beta 6 relative to expression in control MRL(-)+/+ mice, which is associated with collagen-induced arthritis. These data are consistent with a model of normal affinity for negative selection of self-reactive T cells in the thymus of autoimmune strains of mice followed by expansion of autoreactive T cell clones in the peripheral lymphoid organs. The peripheral lymphoid organs of lpr/lpr mice contain an expanded population of abnormal CD4-, CD8-, 6B2+ T cells. Elimination of self-reactive peripheral T cells suggests that these abnormal cells are derived from a CD4+ subpopulation in the thymus. Flow cytometry analysis of peripheral lymph node T cells from MRL-lpr/lpr mice reveal three populations of CD4+ T cells expressing low, intermediate and high intensity of B220 (6B2). This supports the hypothesis that in lpr/lpr mice, self-reactive CD4+ T cells are eliminated in the thymus, and that these cells lose expression of CD4 and acquire expression of 6B2 in the periphery.
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Vacchio, M. S., and R. J. Hodes. "Selective decreases in T cell receptor V beta expression. Decreased expression of specific V beta families is associated with expression of multiple MHC and non-MHC gene products." Journal of Experimental Medicine 170, no. 4 (October 1, 1989): 1335–46. http://dx.doi.org/10.1084/jem.170.4.1335.
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Previous reports of TCR V beta usage, studying either expression of a single V beta in a wide panel of strains (6, 7, 10, 12, 13), or expression of multiple V beta s in a very limited strain distribution (14, 15), have identified instances of clonal deletion of potentially autoreactive T cells specific for either self E alpha E beta or minor lymphocyte stimulatory (Mls) antigens. The present study has investigated the range of self antigens that can influence V beta usage by evaluating expression of 16 V beta families in 30 strains of mice. It was found that significant decreases in expression occur in at least 8 of the 16 V beta families and that dominant influences on the T cell V beta repertoire are exerted by expression of Mlsa, Mlsc, and MHC gene products. Decreased expressions of V beta 5, -11, -12, and -16 were influenced by MHC gene products. The patterns of decreased expression seen in intra-MHC recombinant strains and strains of different non-MHC background were distinct for V beta 11, -12, and -16, suggesting that different ligands are involved in the deletion of T cells expressing each of these V beta genes. Mice expressing Mlsa show decreased expression of V beta 9 as well as V beta 6. Mlsc mice lacked V beta 3 expression in those strains where the expressed MHC type was compatible with a strongly stimulatory Mlsc phenotype. V beta 7 was strongly influenced by both MHC and non-MHC products that are not yet identified. These results demonstrate that strain-specific decreases of mRNA expression occur in a major portion of the TCR repertoire. Self antigens including Mlsa, Mlsc, and E alpha E beta, as well as additional MHC and non-MHC products, appear to induce these decreases in expression in the process of eliminating self-reactive T cells from the mature T cell pool.
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Singh, Ashok K., Snehlata Katheria, Amrendra Kumar, Asiff Zafri, and Mohd Arshad. "Design, Synthesis, Characterization and Antiproliferative Activities of Ru(II) Complexes of Substituted Benzimidazoles." Asian Journal of Chemistry 31, no. 10 (August 30, 2019): 2311–18. http://dx.doi.org/10.14233/ajchem.2019.22162.
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Synthesis of [Ru(PPh3)2(BZM)2Cl2] (BZM= LS1, LS2, LS3, LS4 and LS5) where LS1=(1H-benzo[d] imidazole-2-yl)methanethiol, LS2 = 2-(4-bromobutyl)-1H-benzo[d] imidazole, LS3= 2-(4-nitrophenyl)-1H-benzo[d]imidazole, LS4 = 2-(4-chlorophenyl)-1H-benzo[d]imidazole and LS5= 4-(1H-benzo[d]imidazol-2-yl)aniline (BZM = benzimidazoles, PPh3 = triphenylphosphine) and metal complexes as MR, [ Ru (PPh3)4Cl2], MLS1, MLS2, MLS3, MLS4 and MLS5 for use as potential anticancer compounds have been investigated. The complexes have been characterized by elemental analysis, IR, multinuclear NMR, UV-visible and ESI-MS spectroscopic techniques. The geometries of all complexes have been optimized by using density functional theory (DFT). The cytotoxicity effects of MR, MLS2 and LS1 were also investigated on Human cervical carcinoma cells (HeLa) by MTT assay, ROS generation and nuclear apoptosis assay. The percent cell viability assessed by MTT assay suggested that the synthesized MR, MLS2 and LS1 significantly reduce the viability of HeLa cells, in a dose-dependent manner. The inhibitory concentration (IC50) of MR, MLS2 and LS1 against HeLa cells was found 90.8, 81.8 and 115 μM, respectively. These compounds also induced the over production of intracellular reactive oxygen species (ROS) as well as the condensed and fragmented nucleus, which supports the molecular mechanism of cell death by apoptosis. The investigations suggested that the compounds MR, MLS2 and LS1 induce the cell death in HeLa cells through apoptotic pathway.
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Webb, S. R., A. Okamoto, and J. Sprent. "Analysis of T hybridomas prepared from a T cell clone with three specificities. Recognition of self + X and allo-H-2 determinants segregates from recognition of Mlsa determinants." Journal of Immunology 141, no. 6 (September 15, 1988): 1828–34. http://dx.doi.org/10.4049/jimmunol.141.6.1828.
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Abstract To see k information on T cell recognition of Mlsa determinants, hybridomas were prepared from a well-characterized F23.2+ (V beta 8.2+) T cell clone specific for three different ligands, i.e., 1) Mlsa determinants, 2) fowl gamma-globulin (F gamma G) plus self-H-2 (H-2d), and 3) allo-H-2, e.g., H-2p, determinants. Fusion of the clone to the BW5147 thymoma line produced a triple-reactive T hybridoma which generated two types of spontaneous variants. One type of variant (type I) lost Mlsa reactivity but retained reactivity to both F gamma G/H-2d and allo-H-2p. These variants, which were generated at high frequency, stained strongly with a mAb, A1.57, with idiotypic specificity for the TCR molecules of the parental clone. The second type of variant (type II) reacted to Mlsa determinants but showed no reactivity to F gamma G/H-2d or to allo-H-2p. These variants failed to express the A1.57 idiotypic determinants of the parent clone, but were F23.2+ (V beta 8.2+); nonequilibrium pH gradient electrophoresis analysis suggested that these hybrids expressed a mixed TCR heterodimer composed of the parental clone beta-chain and the BW5147 alpha-chain. Three aspects of the data are very difficult to accommodate with the view that Mlsa, F gamma G, and allo-H-2 determinants are all recognized via a common TCR molecule: 1) the independent (and frequent) segregation of Mlsa reactivity from F gamma G/H-2d and allo-H-2p reactivity, 2) the retention of Mlsa reactivity by the type II variants despite loss of the parental clone alpha-chain, and 3) the loss of Mlsa reactivity by the type I variants despite high expression of the A1.57+ TcR molecules derived from the parental clone. The data support a model in which Mlsa determinants are recognized by a separate T cell structure, which we envisage as a monomorphic accessory molecule unrelated to the TCR. Since the type II hybridoma variants invariably retained quantitatively normal TcR expression, the triggering phase of anti-Mlsa responses appears to be TCR dependent. The model we favor is that anti-Mlsa/Mlsa interaction increases TCR binding with Ia epitopes to above the threshold required for cell triggering. A key feature of this model is that Mlsa and Ia determinants are recognized as separate structures rather than as a complex.
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Webb, S. R., and J. Sprent. "Response of mature unprimed CD8+ T cells to Mlsa determinants." Journal of Experimental Medicine 171, no. 3 (March 1, 1990): 953–58. http://dx.doi.org/10.1084/jem.171.3.953.
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Contrary to existing dogma, evidence is presented that proliferative responses of mature unprimed T cells to Mlsa antigens involve CD8+ cells as well as CD4+ cells. The response of CD8+ cells to Mlsa antigens proved to be heavily dependent on help from CD4+ cells, and responses were stronger in three I-E+ strain combinations than in an I-E- combination. In I-E+ combinations, CD8+ blast cells accounted for 20-25% of the blasts generated from unseparated T cells responding to Mlsa-bearing stimulator cells in vitro; similar findings applied to blast cells generated in vivo. The observation that the majority (greater than or equal to 50%) of Mlsa-stimulated CD8+ cells (and CD4+ cells) were V beta 6+ indicated that CD8+ cells respond to Mlsa antigens, per se, rather than to nonspecific stimuli. Whether CD4+ and CD8+ cells use the same or different H-2-restricting elements to respond to Mlsa antigens has yet to be resolved.
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Rong, Xiaoying, and Ying Huang. "Taxonomic evaluation of the Streptomyces griseus clade using multilocus sequence analysis and DNA–DNA hybridization, with proposal to combine 29 species and three subspecies as 11 genomic species." International Journal of Systematic and Evolutionary Microbiology 60, no. 3 (March 1, 2010): 696–703. http://dx.doi.org/10.1099/ijs.0.012419-0.
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Streptomyces griseus and related species form the biggest but least well-defined clade in the whole Streptomyces 16S rRNA gene tree. Multilocus sequence analysis (MLSA) has shown promising potential for refining Streptomyces systematics. In this investigation, strains of 18 additional S. griseus clade species were analysed and data from a previous pilot study were integrated in a larger MLSA phylogeny. The results demonstrated that MLSA of five housekeeping genes (atpD, gyrB, recA, rpoB and trpB) is better than the previous six-gene scheme, as it provides equally good resolution and stability and is more cost-effective; MLSA using three or four of the genes also shows good resolution and robustness for differentiating most of the strains and is therefore of value for everyday use. MLSA is more suitable for discriminating strains that show >99 % 16S rRNA gene sequence similarity. DNA–DNA hybridization (DDH) between strains with representative MLSA distances revealed a strong correlation between the data of MLSA and DDH. The 70 % DDH value for current species definition corresponds to a five-gene MLSA distance of 0.007, which could be considered as the species cut-off for the S. griseus clade. It is concluded that the MLSA procedure can be a practical, reliable and robust alternative to DDH for the identification and classification of streptomycetes at the species and intraspecies levels. Based on the data from MLSA and DDH, as well as cultural and morphological characteristics, 18 species and three subspecies of the S. griseus clade are considered to be later heterotypic synonyms of 11 genomic species: Streptomyces griseinus and Streptomyces mediolani as synonyms of Streptomyces albovinaceus; Streptomyces praecox as a synonym of Streptomyces anulatus; Streptomyces olivoviridis as a synonym of Streptomyces atroolivaceus; Streptomyces griseobrunneus as a synonym of Streptomyces bacillaris; Streptomyces cavourensis subsp. washingtonensis as a synonym of Streptomyces cyaneofuscatus; Streptomyces acrimycini, Streptomyces baarnensis, Streptomyces caviscabies and Streptomyces flavofuscus as synonyms of Streptomyces fimicarius; Streptomyces flavogriseus as a synonym of Streptomyces flavovirens; Streptomyces erumpens, ‘Streptomyces ornatus’ and Streptomyces setonii as synonyms of Streptomyces griseus; Streptomyces graminofaciens as a synonym of Streptomyces halstedii; Streptomyces alboviridis, Streptomyces griseus subsp. alpha, Streptomyces griseus subsp. cretosus and Streptomyces luridiscabiei as synonyms of Streptomyces microflavus; and Streptomyces californicus and Streptomyces floridae as synonyms of Streptomyces puniceus.
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Lynch, D. H., R. E. Gress, B. W. Needleman, S. A. Rosenberg, and R. J. Hodes. "T cell responses to Mls determinants are restricted by cross-reactive MHC determinants." Journal of Immunology 134, no. 4 (April 1, 1985): 2071–78. http://dx.doi.org/10.4049/jimmunol.134.4.2071.
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Abstract The studies presented here investigated the relationship between T cell recognition of MHC-encoded products and non-MHC-linked Mls determinants. The first aspect addressed whether Mls-reactive T cells recognize Mls-encoded products alone or in association with MHC-encoded determinants. Initial studies used Mlsa-specific T cell clones that were generated by repeated stimulation of C57BL/6 or B10.A(5R) spleen cells with DBA/2 lymphoid cells. These clones recognized Mlsa on cells expressing MHC products of the H-2b, H-2d, and H-2k haplotypes, but not the H-2q haplotype. Thus, these cloned T cells were found to recognize Mlsa products in association with public but demonstrably polymorphic H-2 determinants. The question of whether T cell clones that were specific for self-H-2 determinants (autoreactive) or soluble antigen plus syngeneic H-2 (antigen-specific) could also be stimulated by Mlsa determinants was also addressed. A substantial proportion of the antigen-specific or autoreactive T cell clones tested were stimulated by Mlsa determinants. Furthermore, stimulation of these clones by Mlsa was H-2 restricted. The pattern of H-2-restricted recognition of Mlsa by these clones was not distinguishable from that observed in the Mlsa-specific T cell clones, nor was it influenced by the primary specificity or H-2 restriction pattern of a given clone. Although these findings provide a means of explaining the observation that Mls-reactive T cells exist at extremely high precursor frequencies, they also raise questions regarding the nature of the receptor structures which are used by a single T cell in the recognition of two or more apparently distinct stimuli.
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Ryan, J. J., J. J. Mond, and F. D. Finkelman. "Genetic analysis of the presentation of minor lymphocyte stimulating determinants. I. Combined importance of MHC and non-MHC influences." Journal of Immunology 141, no. 4 (August 15, 1988): 1063–73. http://dx.doi.org/10.4049/jimmunol.141.4.1063.
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Abstract In the course of studying the MHC restriction of minor lymphocyte stimulating (Mls) determinants, we observed that variation in the ability to present Mlsc determinants occurred with stimulator cells from different mouse strains that express the same class II MHC restricting elements; for example, one Iad-bearing strain, C3H.HTG, presented this non-MHC moiety, whereas another, C3H.OH, could not. As another example, the prototype Mlsb nonstimulatory H-2d stimulator cell, BALB/c, was shown to encode Mlsc even though it failed to trigger proliferation across this non-MHC barrier. In contrast, H-2d-compatible DBA/2 stimulator cells were capable of eliciting detectable levels of unprimed responder T cell proliferation across an Mlsc difference. Even when the BALB/c H-2d haplotype was replaced with the fully permissive H-2K halplotype, these BALB.K stimulator cells presented Mlsc (but not MHC) less effectively than H-2K-compatible C3H/HeJ stimulator cells. Analysis of the Mlsc-presenting capacity of stimulator cells obtained from (BALB.K x C3H) F1 x BALB.K first backcross and (BALB.K x C3H)F2 animals indicated that non-MHC-control influencing stimulatory ability of this non-H-2 Ag was multigenic. In addition, the capacity of DBA/2 to present Mlsa determinants more effectively than MHC-identical LT/ChReSv stimulator cells may indicate that the presentation of this Mls specificity is also influenced by non-MHC Ir genes. Thus the Mls phenotype of an animal should be considered the combined result of an Mls structural gene, the MHC haplotype, and multiple non-H-2 regulatory influences.
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Golidonova, Kristina A., Edward I. Korenberg, and Alexander L. Gintsburg. "Optimized multilocus sequence analysis for laboratory identification of pathogens of ixodid tick-borne borreliosis." Journal of microbiology, epidemiology and immunobiology 99, no. 5 (December 7, 2022): 514–24. http://dx.doi.org/10.36233/0372-9311-296.
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Introduction. The most common etiological agents of ixodid tick-borne borreliosis (ITBB) in Russia are Borrelia garinii, B. afzelii, B. bavariensis. Multilocus sequence typing and multilocus sequence analysis (MLSA) have been used in recent studies for Borrelia species identification. The results of using the MLSA scheme for identification of pathogens causing erythemic forms of ITBB have been presented earlier.
The purpose of the study was to explore the possibility of MLSA optimization for laboratory identification of ITBB pathogens. Objectives: comparative analysis of nucleotide sequences of 6 conserved genes (rrs, hbb, fla, groEL, recA, ospA) and the rrfA-rrlB intergenic spacer, which are recommended by the MLSA protocol; identification of the minimum set of genes, the concatenated sequences of which are essential for species identification of Borrelia isolates.
Materials and methods. The sequences of the above loci of 23 reference isolates collected from patients with ITBB and assigned, using MLSA, to B. bavariensis were compared with the sequences of similar genes of other Borrelia species available in international databases. The UPGMA method was used to build and analyze dendrograms based on the obtained data.
Results. The sequences of ospA gene loci of reference species demonstrated the greatest difference (not less than 8.5%) from the sequences of the above gene in other analyzed species of Borrelia; approximately similar species-related differences (not less than 6.7%) were demonstrated by the comparison of recA gene sequences. The sequences of the identified variants of these two genes in B. bavariensis differed from the sequences of the similar genes in the most closely related species B. garinii. The dendrogram of the concatenated nucleotide sequences of recA and ospA genes demonstrated that it was totally consistent with the results of identification of the isolates based on the MLSA protocol.
Conclusion. The optimized approach to MLSA of the B. burgdorferi sensu lato group suggests that species identification should be based on the concatenated analysis of loci of only two genes (recA and ospA) out of 7 loci recommended by the MLSA protocol.
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Waite, Debra J., Richard A. Miller, and Geoffrey H. Sunshine. "Neonatal tolerance induction to Mlsa." Cellular Immunology 117, no. 1 (November 1988): 70–77. http://dx.doi.org/10.1016/0008-8749(88)90077-9.
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Waite, Debra J., and Geoffrey H. Sunshine. "Neonatal tolerance induction to Mlsa." Cellular Immunology 117, no. 1 (November 1988): 78–88. http://dx.doi.org/10.1016/0008-8749(88)90078-0.
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Webb, S. R., J. H. Li, I. MacNeil, P. Marrack, J. Sprent, and D. B. Wilson. "T cell receptors for responses to Mls determinants and allo-H-2 determinants appear to be encoded on different chromosomes." Journal of Experimental Medicine 161, no. 1 (January 1, 1985): 269–74. http://dx.doi.org/10.1084/jem.161.1.269.
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Previous studies have shown that T cell clones specific for strong Mlsa,d determinants concomitantly display apparently random reactivity to allo-H-2 determinants. One explanation for this finding is that T cell recognition of Mlsa,d and allo-H-2 determinants is controlled by separate sets of receptors. If these receptors were chromosomally unlinked, karyotypically unstable T cell hybrids with dual reactivity for Mlsa,d and particular allo-H-2 determinants would be expected, occasionally, to lose reactivity for one set of determinants, but not the other. The results presented here provide direct support for this prediction.
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Abe, R., M. Foo-Phillips, L. G. Granger, and O. Kanagawa. "Characterization of the Mlsf system. I. A novel "polymorphism" of endogenous superantigens." Journal of Immunology 149, no. 11 (December 1, 1992): 3429–39. http://dx.doi.org/10.4049/jimmunol.149.11.3429.
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Abstract In addition to Mlsa (Mls-1a) and Mlsc (Mls-2a, Mls-3a), we and others have recently described a third set of stimulatory minor lymphocyte stimulating (Mls) determinants, which are ligands for "I-E related" V beta, V beta 5, V beta 11, and V beta 12. Although all V beta associated with the recognition of the conventional Mls determinants are, in general, uniformly deleted in those animals expressing relevant Mls, expression of Mlsf-related V beta reveals various deletion patterns among different strains. Here we describe extensive genetic studies to evaluate the relationship among the self-Ag responsible for clonal deletion of T cells bearing Mlsf-related V beta by using antibodies specific for TCR V beta chain. In addition, a panel of T cell clones specific for the Mlsf determinant were generated and employed to analyze the determinant specificity, which is recognized by Mlsf-reactive T cells in vitro as well as the role of class II molecules in T cell recognition of the Mlsf determinants. The results of these two independent approaches provide evidence that the Mlsf system is composed of a set of gene products that reveal a unique polymorphism in the induction of clonal deletion in vivo and in T cell activation in vitro. One of these gene products causes almost complete deletion of the self-Mlsf reactive T cell repertoire in vivo and elicits a strong proliferative response to Mlsf-specific T cell clones. Expression of the other gene products results in the clonal deletion of only part of the Mlsf-reactive T cell repertoire. Furthermore, the response pattern of Mlsf-specific clones to intra-MHC recombinant inbred strains and the inhibition pattern of these clones by anti-class II antibody suggested that although expression of the I-E molecule is essential for T cell recognition of Mlsf determinants, the A beta gene may also contribute to the efficient presentation of Mlsf determinants by forming unique class II E alpha A beta molecules.
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Abe, R., O. Kanagawa, M. A. Sheard, B. Malissen, and M. Foo-Phillips. "Characterization of a new minor lymphocyte stimulatory system. I. Cluster of self antigens recognized by "I-E-reactive" V beta s, V beta 5, V beta 11, and V beta 12 T cell receptors for antigen." Journal of Immunology 147, no. 3 (August 1, 1991): 739–49. http://dx.doi.org/10.4049/jimmunol.147.3.739.
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Abstract In the mouse, two sets of V beta gene products have been shown to be associated with T cell recognition of endogenous self Ag. One of these is the set of V beta associated with T cell reactivities to stimulatory Mls gene products, Mlsa (V beta 6, V beta 8.1, V beta 9) or Mlsc (V beta 3); another is the set of V beta, such as V beta 5, V beta 11, V beta 12, or V beta 17a, which were originally found to be related to I-E recognition. Although the Mls system has been well characterized, little is known about the nature of the ligands for the second set of V beta. In this work, we describe the evidence that the natural ligand or ligands of V beta 5, V beta 11, and V beta 12 may be novel Mls determinants that are recognized by naive T cells at a high precursor frequency and function as the ligand for clonal deletion of self-reactive T cells by negative selection. However, surprisingly, unlike the conventional Mls system, in which all V beta associated with Mlsa recognition or Mlsc recognition are uniformly deleted in those animals expressing the relevant Mls type, expression of these three V beta segregates independently among strains. Based on these observations, the nature of T cell recognition for this new Mls gene product(s) is discussed.
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Chapman, J. R., R. K. Taylor, B. S. Weir, M. K. Romberg, J. L. Vanneste, J. Luck, and B. J. R. Alexander. "Phylogenetic Relationships Among Global Populations of Pseudomonas syringae pv. actinidiae." Phytopathology® 102, no. 11 (November 2012): 1034–44. http://dx.doi.org/10.1094/phyto-03-12-0064-r.
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Pseudomonas syringae pv. actinidiae, the causal agent of canker in kiwifruit (Actinidia spp.) vines, was first detected in Japan in 1984, followed by detections in Korea and Italy in the early 1990s. Isolates causing more severe disease symptoms have recently been detected in several countries with a wide global distribution, including Italy, New Zealand, and China. In order to characterize P. syringae pv. actinidiae populations globally, a representative set of 40 isolates from New Zealand, Italy, Japan, South Korea, Australia, and Chile were selected for extensive genetic analysis. Multilocus sequence analysis (MLSA) of housekeeping, type III effector and phytotoxin genes was used to elucidate the phylogenetic relationships between P. syringae pv. actinidiae isolates worldwide. Four additional isolates, including one from China, for which shotgun sequence of the whole genome was available, were included in phylogenetic analyses. It is shown that at least four P. syringae pv. actinidiae MLSA groups are present globally, and that marker sets with differing evolutionary trajectories (conserved housekeeping and rapidly evolving effector genes) readily differentiate all four groups. The MLSA group designated here as Psa3 is the strain causing secondary symptoms such as formation of cankers, production of exudates, and cane and shoot dieback on some kiwifruit orchards in Italy and New Zealand. It is shown that isolates from Chile also belong to this MLSA group. MLSA group Psa4, detected in isolates collected in New Zealand and Australia, has not been previously described. P. syringae pv. actinidiae has an extensive global distribution yet the isolates causing widespread losses to the kiwifruit industry can all be traced to a single MLSA group, Psa3.
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Papke, R. Thane, Emma White, Prajwal Reddy, Griffin Weigel, Masahiro Kamekura, Hiroaki Minegishi, Ron Usami, and Antonio Ventosa. "A multilocus sequence analysis approach to the phylogeny and taxonomy of the Halobacteriales." International Journal of Systematic and Evolutionary Microbiology 61, no. 12 (December 1, 2011): 2984–95. http://dx.doi.org/10.1099/ijs.0.029298-0.
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Members of the order Halobacteriales are obligate extreme halophiles that belong to the domain Archaea. The classification of the Halobacteriales currently relies on a polyphasic approach, which integrates phenotypic, genotypic and chemotaxonomic characterization. However, the most utilized genetic marker for phylogeny, the 16S rRNA gene, has multiple drawbacks for use with the Halobacteriales: the species of many genera exhibit large intragenic differences between multiple ribosomal RNA operons, the gene is too conserved to discriminate reliably at the species level and it appears to be the most frequently recombined gene between closely related species. Moreover, the Halobacteriales is a rapidly expanding group due to recent successes at cultivating novel strains from a diverse set of hypersaline environments; a fast, reliable, inexpensive, portable molecular method for discriminating species is required for their investigation. Recently, multilocus sequence analysis (MLSA) has been shown to be an effective tool for strain identification and taxonomic designation, even for those taxa that experience frequent lateral gene transfer and homologous recombination. In this study, MLSA was utilized for evolutionary and taxonomic investigation of the Halobacteriales. Efficacy of the MLSA approach was tested across a hierarchical gradient using 52 halobacterial strains, representing 33 species (including names without standing in nomenclature) and 14 genera. A subset of 21 strains from the genus Haloarcula was analysed separately to test the sensitivity and relevance of the MLSA approach among closely related strains and species. The results demonstrated that MLSA differentiated individual strains, reliably grouped strains into species and species into genera and identified potential novel species and also family-like relationships. This study demonstrates that MLSA is a rapid and informative molecular method that will probably accommodate strain analysis at any taxonomic level within the Halobacteriales.
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Grankvist, Anna, Edward R. B. Moore, Liselott Svensson Stadler, Sona Pekova, Christian Bogdan, Walter Geißdörfer, Jenny Grip-Lindén, et al. "Multilocus Sequence Analysis of Clinical “Candidatus Neoehrlichia mikurensis” Strains from Europe." Journal of Clinical Microbiology 53, no. 10 (July 8, 2015): 3126–32. http://dx.doi.org/10.1128/jcm.00880-15.
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“CandidatusNeoehrlichia mikurensis” is the tick-borne agent of neoehrlichiosis, an infectious disease that primarily affects immunocompromised patients. So far, the genetic variability of “Ca. Neoehrlichia” has been studied only by comparing 16S rRNA genes andgroELoperon sequences. We describe the development and use of a multilocus sequence analysis (MLSA) protocol to characterize the genetic diversity of clinical “Ca. Neoehrlichia” strains in Europe and their relatedness to other species within theAnaplasmataceaefamily. Six genes were selected:ftsZ,clpB,gatB,lipA,groEL, and 16S rRNA. Each MLSA locus was amplified by real-time PCR, and the PCR products were sequenced. Phylogenetic trees of MLSA locus relatedness were constructed from aligned sequences. Blood samples from 12 patients with confirmed “Ca. Neoehrlichia” infection from Sweden (n= 9), the Czech Republic (n= 2), and Germany (n= 1) were analyzed with the MLSA protocol. Three of the Swedish strains exhibited identicallipAsequences, while thelipAsequences of the strains from the other nine patients were identical to each other. One of the Czech strains had one differing nucleotide in theclpBsequence from the sequences of the other 11 strains. All 12 strains had identical sequences for the genes 16S rRNA,ftsZ,gatB, andgroEL. According to the MLSA, among theAnaplasmataceae, “Ca. Neoehrlichia” is most closely related toEhrlichia ruminantium, less so toAnaplasma phagocytophilum, and least toWolbachiaendosymbionts. To conclude, three sequence types of infectious “Ca. Neoehrlichia” were identified: one in the west of Sweden, one in the Czech Republic, and one spread throughout Europe.
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Schlicher, Jessica, Sarah Schmitt, Marc J. A. Stevens, Roger Stephan, and Giovanni Ghielmetti. "Molecular Characterization of Corynebacterium pseudotuberculosis Isolated over a 15-Year Period in Switzerland." Veterinary Sciences 8, no. 8 (July 30, 2021): 151. http://dx.doi.org/10.3390/vetsci8080151.
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Corynebacterium pseudotuberculosis biovar Ovis is the etiological agent of the contagious and chronic disease caseous lymphadenitis (CLA) in sheep and goats. The economic impact of CLA in Switzerland remains largely unknown, and the transmission modalities, as well as the genetic diversity of circulating strains, are poorly understood. This work presents further characterization data for 215 C. pseudotuberculosis isolates from sheep, goats and a dromedary originating from Switzerland and the Principality of Liechtenstein, collected over a 15-year period. The isolates were classified into the two biovars Ovis and Equi, analyzed for the presence of the diphtheria-like toxin gene and characterized using MLSA. All sheep and goat isolates were classified as C. pseudotuberculosis biovar Ovis. The isolate from a dromedary was classified as biovar Equi. No isolates harboring the diphtheria-like toxin gene were detected. Phylogenetic analysis of the concatenated sequences of four genes revealed the existence of 24 clusters. There was no correlation between MLSA sequence types, year of isolation and the geographical origin of the isolates. These findings confirm the presence of several MLSA sequence types in the study area and over a 15-year period. Moreover, no sheep- and goat-specific MLSA sequence types were found.
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da Gama, Marco Aurélio Siqueira, Rosa de Lima Ramos Mariano, Wilson José da Silva Júnior, Antônio Roberto Gomes de Farias, Maria Angélica Guimarães Barbosa, Marisa Álvares da Silva Velloso Ferreira, César Raimundo Lima Costa Júnior, Liliana Andréa Santos, and Elineide Barbosa de Souza. "Taxonomic Repositioning of Xanthomonas campestris pv. viticola (Nayudu 1972) Dye 1978 as Xanthomonas citri pv. viticola (Nayudu 1972) Dye 1978 comb. nov. and Emendation of the Description of Xanthomonas citri pv. anacardii to Include Pigmented Isolates Pathogenic to Cashew Plant." Phytopathology® 108, no. 10 (October 2018): 1143–53. http://dx.doi.org/10.1094/phyto-02-18-0037-r.
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Grapevine bacterial canker, which is caused by Xanthomonas campestris pv. viticola, is one of the most important grapevine diseases in the northeastern region of Brazil. This disease causes severe damage and represents a high potential risk to the development of Brazilian viticulture. In turn, pigmented isolates pathogenic to cashew plant, making cashew fruit unfit for sale, also have been detected in Northeastern Brazil. Given that the taxonomic position of these bacteria is unclear, the multilocus sequence analysis (MLSA) technique, average nucleotide identity (ANI) values and tetranucleotide frequency correlation coefficients (TETRA) were used to analyze their phylogenetic relationship in relation to other Xanthomonas species. X. campestris pv. viticola was closely related to X. citri pv. mangiferaeindicae (repetitive-polymerase chain reaction [rep-PCR], MLSA, and ANI) and X. citri subsp. citri (MLSA and ANI). Pigmented isolates pathogenic to cashew plant were closely related to X. citri pv. anacardii (rep-PCR, MLSA, ANI, and TETRA). The results obtained in this study support the emendation of the description of X. citri pv. anacardii to include pigmented isolates of Xanthomonas pathogenic to cashew plant. In addition, the reclassification of X. campestris pv. viticola as X. citri pv. viticola comb. nov. is suggested.
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Winkelmann, Nadine, Ulrike Jaekel, Carolin Meyer, Wilbert Serrano, Reinhard Rachel, Ramon Rosselló-Mora, and Jens Harder. "Determination of the Diversity of Rhodopirellula Isolates from European Seas by Multilocus Sequence Analysis." Applied and Environmental Microbiology 76, no. 3 (November 30, 2009): 776–85. http://dx.doi.org/10.1128/aem.01525-09.
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ABSTRACT In the biogeography of microorganisms, the habitat size of an attached-living bacterium has never been investigated. We approached this theme with a multilocus sequence analysis (MLSA) study of new strains of Rhodopirellula sp., an attached-living planctomycete. The development of an MLSA for Rhodopirellula baltica enabled the characterization of the genetic diversity at the species level, beyond the resolution of the 16S rRNA gene. The alleles of the nine housekeeping genes acsA, guaA, trpE, purH, glpF, fumC, icd, glyA, and mdh indicated the presence of 13 genetically defined operational taxonomic units (OTUs) in our culture collection. The MLSA-based OTUs coincided with the taxonomic units defined by DNA-DNA hybridization experiments. BOX-PCR supported the MLSA-based differentiation of two closely related OTUs. This study established a taxon-area relationship of cultivable Rhodopirellula species. In European seas, three closely related species covered the Baltic Sea and the eastern North Sea, the North Atlantic region, and the southern North Sea to the Mediterranean. The last had regional genotypes, as revealed by BOX-PCR. This suggests a limited habitat size of attached-living Rhodopirellula species.
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Kanagawa, O., and R. Maki. "Inhibition of MHC class II-restricted T cell response by Lyt-2 alloantigen." Journal of Experimental Medicine 170, no. 3 (September 1, 1989): 901–12. http://dx.doi.org/10.1084/jem.170.3.901.
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T cell hybridomas were established by fusing a CD8+ V beta 8.1+ CTL clone and a CD4+ V beta 8.1+ helper T lymphocyte (HTL) clone to the thymoma cell line BW5147. In contrast to the HTL x BW hybridomas, which retain the same antigen specificity as the original T cell clone, the CTL x BW hybridomas lost the class I MHC-restricted antigen response but acquired a new specificity to Mlsa antigen. Mlsa reactivity of CTL x BW hybridomas was shown to be mediated by the CTL TCR as assayed by inhibition using an anticlonotypic antibody to the CTL clone. Since hybridomas established with BW5147 lose CD8 expression, we have introduced the CD8 molecule into CTL x BW5147 hybridomas by gene transfection. The CD8+ V beta 8.1+ hybridoma was no longer capable of reacting to Mlsa antigen but exhibited the same antigen specificity as the parental CTL clone. Furthermore, the presence of the transfected CD8 molecule in the HTL x BW hybridomas was found to be inhibitory to class II MHC-restricted antigen reactivity. These results demonstrate that, besides its role in increasing the overall avidity of T cell-class I MHC/antigen interaction, the CD8 molecule inhibits T cell-class II MHC gene product/antigen interaction. This negative effect of the CD8 molecule on a class II MHC-restricted response may account for the failure of CD8+ T cells using either V beta 8.1 or V beta 6, which impart reactivity to the Mlsa antigen on CD4+ T cells, to respond to the Mlsa antigen.
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Abe, R., M. Foo-Phillips, and R. J. Hodes. "Analysis of Mlsc genetics. A novel instance of genetic redundancy." Journal of Experimental Medicine 170, no. 4 (October 1, 1989): 1059–73. http://dx.doi.org/10.1084/jem.170.4.1059.
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The identity of the self determinants involved in the selection of the T cell repertoire has been a matter of considerable interest. In addition to the apparent critical role of MHC gene products, accumulated experimental results indicate the importance of non-MHC gene products in T cell repertoire selection. In particular, murine Mlsa and Mlsc determinants have been shown to be highly stimulatory to allogeneic T cells and to be involved in the negative selection (elimination) of self-reactive T cells expressing selected TCR V beta segments. In this work, a unique phenomenon of genetic redundancy is described in the control of Mlsc expression: Mlsc appears to be controlled by at least two unlinked loci, and the product of either one of these loci is sufficient to evoke Mlsc-specific T cell response and to act as a ligand in the deletion of self Mlsc-reactive V beta 3+ T cells. Based on these findings, we propose a possible explanation for the fact that Mls-like genes or gene products have not been identified in other species such as man.
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Webb, S. R., J. Hutchinson, K. Hayden, and J. Sprent. "Expansion/deletion of mature T cells exposed to endogenous superantigens in vivo." Journal of Immunology 152, no. 2 (January 15, 1994): 586–97. http://dx.doi.org/10.4049/jimmunol.152.2.586.
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Abstract Previous studies have shown that in thymectomized hosts exposure of mature T cells to Mlsa (mtv-7) Ag in vivo leads to specific tolerance and the disappearance of Mlsa-reactive V beta 6+ T cells after an initial phase of T cell expansion. To investigate the factors controlling postthymic elimination of mature T cells, we examined T cell responses to Mlsa and other endogenous superantigens in a number of different strain combinations. The results show that the extent of T cell expansion/deletion is influenced by various factors, including the H-2 haplotype of the host and the particular V beta studied. Collectively, the results suggest that the extent of elimination of mature T cells is variable and may be a function of high avidity interactions with APC.
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Roberts, J. L., R. Abe, E. W. Shores, and A. Singer. "Expression of Mls determinants in mice exhibiting the severe combined immunodeficiency (scid) mutation or X-linked immunodeficiency (xid) defect." Journal of Immunology 149, no. 5 (September 1, 1992): 1577–82. http://dx.doi.org/10.4049/jimmunol.149.5.1577.
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Abstract While Ig+ B cells appear to be the principal cell type expressing immunogenic minor lymphocyte stimulatory (Mls) determinants, both T cells and B cells are capable of mediating deletion of developing Mls-reactive thymocytes. In addition, levels of mouse mammary tumor proviral transcripts are increased after B or T cell stimulation, and expression of functional Mls determinants is augmented by activation of B cells. These findings suggest Mls determinants are present on B and T lymphocytes, and that activation of B and T cells augments Mls expression. In the present study, we wished to determine whether B and T cells were required for expression of Mls determinants by examining mice with severe combined immunodeficiency (SCID) containing no detectable Ig+ B cells or TCR+ T cells, as well as animals that expressed the X-linked immunodeficiency (xid) defect and lacked a subset of mature B cells. We found Mlsa-reactive V beta 6hi T cells were deleted from thymi of male (CBA/NxAKR/J)F1 xid mice, and that spleen cells from these animals stimulated anti-Mlsa mixed lymphocyte responses by unprimed B10.BR spleen T cells. In addition, Mlsc-reactive V beta 3hi AKR/J thymocytes and spleen T cells were deleted in AKR/J----SCID bone marrow chimeras, and spleen cells from SCID mice stimulated proliferation by an Mlsc-specific T cell clone. These results demonstrate that both xid mice and SCID animals express Mls determinants that mediate deletion of developing, Mls-responsive thymocytes and stimulate proliferation of mature, Mls-reactive T cells. Hence, mature B cells and T cells are not essential for Mls expression.
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Dhabaan, Ghulam, Julianne Kus, Deepali Kumar, Atul Humar, Shahid Husain, and Tony Mazzulli. "Molecular identification of Aspergillus fumigatus complex from lung transplant recipients using multilocus sequencing analysis (MLSA)." Official Journal of the Association of Medical Microbiology and Infectious Disease Canada 7, no. 1 (March 1, 2022): 54–63. http://dx.doi.org/10.3138/jammi-2021-0004.
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BACKGROUND: Aspergillus infection causes significant morbidity and mortality among lung transplant recipients (LTRs). It is primarily caused by Aspergillus fumigatus. Other closely related species belonging to the section Fumigati have also been found. These cryptic species are often misidentified as A. fumigatus. Thus, we used multilocus sequencing analysis (MLSA) of the calmodulin, β-tubulin, and hydrophobin gene sequences to identify these species and to determine the frequency with which they occur among LTRs. METHODS: A total of 81 A. fumigatus isolates were initially isolated from bronchoalveolar lavage fluid or sputum specimens collected from lung transplant patients. These isolates were then sub-cultured and genotyped using MLSA. Of these isolates, 53, 17, and 11 were isolated from double LTRs, single LTRs, and pre-LTRs, respectively. RESULTS: All isolates (100%) carried DNA sequences identical to those of A. fumigatus reference strains and thus clustered in the same clade with A. fumigatus. Analysis of the MLSA data revealed that A. fumigatus species were the only species recovered in this population of LTRs. The MLSA results were consistent with those routinely obtained by conventional mycological procedures in the microbiology laboratory. CONCLUSIONS: A. fumigatus appears to be the primary causative agent of colonization or invasive aspergillosis among LTRs. No cryptic species were identified.
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Joseph, Susan, Esin Cetinkaya, Hana Drahovska, Arturo Levican, Maria J. Figueras, and Stephen J. Forsythe. "Cronobacter condimenti sp. nov., isolated from spiced meat, and Cronobacter universalis sp. nov., a species designation for Cronobacter sp. genomospecies 1, recovered from a leg infection, water and food ingredients." International Journal of Systematic and Evolutionary Microbiology 62, Pt_6 (June 1, 2012): 1277–83. http://dx.doi.org/10.1099/ijs.0.032292-0.
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A re-evaluation of the taxonomic position of five strains, one assigned to Cronobacter sakazakii (strain 1330T, isolated from spiced meat purchased in Slovakia), two previously assigned to Cronobacter genomospecies 1 (strains NCTC 9529T and 731, isolated from water and a leg infection, respectively) and two previously assigned to Cronobacter turicensis (strains 96 and 1435, isolated from onion powder and rye flour, respectively) was carried out. The analysis included phenotypic characterization, 16S rRNA gene sequencing and multilocus sequence analysis (MLSA) of seven housekeeping genes (atpD, fusA, glnS, gltB, gyrB, infB, ppsA; 3036 bp). 16S rRNA gene sequence analysis and MLSA showed that strain 1330T formed an independent phylogenetic lineage in the MLSA, with Cronobacter dublinensis LMG 23823T as the closest neighbour. DNA–DNA reassociation and phenotypic analysis revealed that strain 1330T represented a novel species, for which the name Cronobacter condimenti sp. nov. is proposed (type strain 1330T = CECT 7863T = LMG 26250T). Strains NCTC 9529T, 731, 96 and 1435 clustered together within an independent phylogenetic lineage, with C. turicensis LMG 23827T as the closest neighbour in the MLSA. DNA–DNA reassociation and phenotypic analysis confirmed that these strains represent a novel species, for which the name Cronobacter universalis sp. nov. is proposed (type strain NCTC 9529T = CECT 7864T = LMG 26249T).
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Thompson, Cristiane C., Vanessa E. Emmel, Erica L. Fonseca, Michel A. Marin, and Ana Carolina P. Vicente. "Streptococcal taxonomy based on genome sequence analyses." F1000Research 2 (March 1, 2013): 67. http://dx.doi.org/10.12688/f1000research.2-67.v1.
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The identification of the clinically relevant viridans streptococci group, at species level, is still problematic. The aim of this study was to extract taxonomic information from the complete genome sequences of 67 streptococci, comprising 19 species, by means of genomic analyses, multilocus sequence analysis (MLSA), average amino acid identity (AAI), genomic signatures, genome-to-genome distances (GGD) and codon usage bias. We then attempted to determine the usefulness of these genomic tools for species identification in streptococci. Our results showed that MLSA, AAI and GGD analyses are robust markers to identify streptococci at the species level, for instance,S. pneumoniae,S. mitis, andS. oralis. AStreptococcusspecies can be defined as a group of strains that share ≥ 95% DNA similarity in MLSA and AAI, and > 70% DNA identity in GGD. This approach allows an advanced understanding of bacterial diversity.
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Jackson, Emily E., Naqash Masood, Khaled Ibrahim, Noémie Urvoy, Sumyya Hariri, and Stephen J. Forsythe. "Description of Siccibacter colletis sp. nov., a novel species isolated from plant material, and emended description of Siccibacter turicensis." International Journal of Systematic and Evolutionary Microbiology 65, Pt_4 (April 1, 2015): 1335–41. http://dx.doi.org/10.1099/ijs.0.000108.
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A re-evaluation of the taxonomic position of two strains, 1383T and 2249, isolated from poppy seeds and tea leaves, which had been identified as Siccibacter turicensis (formerly Cronobacter zurichensis ), was carried out. The analysis included phenotypic characterization, 16S rRNA gene sequencing, multilocus sequence analysis (MLSA) of five housekeeping genes (atpD, fusA, glnS, gyrB and infB; 2034 bp) and ribosomal MLSA (53 loci; 22 511 bp). 16S rRNA gene sequence analysis and MLSA showed that the strains formed an independent phylogenetic lineage, with Siccibacter turicensis LMG 23730T as the closest neighbour. Average nucleotide identity analysis and phenotypic analysis confirmed that these strains represent a novel species, for which the name Siccibacter colletis sp. nov. is proposed. The type strain is 1383T ( = NCTC 14934T = CECT 8567T = LMG 28204T). An emended description of Siccibacter turicensis is also provided.
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Wu, Alfred M., and M. Ramesh. "Poverty Reduction in Urban China: The Impact of Cash Transfers." Social Policy and Society 13, no. 2 (January 31, 2014): 285–99. http://dx.doi.org/10.1017/s1474746413000626.
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The extent to which social protection programmes in general, and targeted programmes in particular, actually alleviate poverty has been a central issue in development debates for decades. The objective of this article is to contribute to the debate by empirically examining the poverty-alleviation effects of one of the largest targeted programmes in the world: the Minimum Living Standard Assistance (MLSA) or Dibao in China. Using newly available data on MLSA spending and a unique panel survey dataset covering the 1993 to 2009 period, this research investigates the impact of the MLSA on poverty alleviation. The analyses using fixed-effects and random-effects logit models and hierarchical liner models offer insights that go beyond the existing studies on the subject. Findings from the study confirm that targeted social protection programmes are an effective tool for reducing poverty.
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Richter, Dania, Danièle Postic, Natacha Sertour, Ian Livey, Franz-Rainer Matuschka, and Guy Baranton. "Delineation of Borrelia burgdorferi sensu lato species by multilocus sequence analysis and confirmation of the delineation of Borrelia spielmanii sp. nov." International Journal of Systematic and Evolutionary Microbiology 56, no. 4 (April 1, 2006): 873–81. http://dx.doi.org/10.1099/ijs.0.64050-0.
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To evaluate multilocus sequence analysis (MLSA) for taxonomic purposes in the delineation of species within Borrelia burgdorferi sensu lato, seven relevant loci of various strains for which extensive DNA–DNA reassociation data were available were sequenced. MLSA delineation proved to be fully concordant with conventional methods. Our analysis confirmed the delineation of a novel species, Borrelia spielmanii sp. nov., previously known as ‘Borrelia spielmani’ Richter et al. 2004, with strain PC-Eq17N5T (=DSM 16813T=CIP 108855T) as the type strain.
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Tanaka, Mami, Sayaka Mino, Yoshitoshi Ogura, Tetsuya Hayashi, and Tomoo Sawabe. "Availability of Nanopore sequences in the genome taxonomy for Vibrionaceae systematics: Rumoiensis clade species as a test case." PeerJ 6 (June 18, 2018): e5018. http://dx.doi.org/10.7717/peerj.5018.
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Whole genome sequence comparisons have become essential for establishing a robust scheme in bacterial taxonomy. To generalize this genome-based taxonomy, fast, reliable, and cost-effective genome sequencing methodologies are required. MinION, the palm-sized sequencer from Oxford Nanopore Technologies, enables rapid sequencing of bacterial genomes using minimal laboratory resources. Here we tested the ability of Nanopore sequences for the genome-based taxonomy of Vibrionaceae and compared Nanopore-only assemblies to complete genomes of five Rumoiensis clade species: Vibrio aphrogenes, V. algivorus, V. casei, V. litoralis, and V. rumoiensis. Comparison of overall genome relatedness indices (OGRI) and multilocus sequence analysis (MLSA) based on Nanopore-only assembly and Illumina or hybrid assemblies revealed that errors in Nanopore-only assembly do not influence average nucleotide identity (ANI), in silico DNA-DNA hybridization (DDH), G+C content, or MLSA tree topology in Vibrionaceae. Our results show that the genome sequences from Nanopore-based approach can be used for rapid species identification based on the OGRI and MLSA.
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Glaeser, Stefanie P., and Peter Kämpfer. "Multilocus sequence analysis (MLSA) in prokaryotic taxonomy." Systematic and Applied Microbiology 38, no. 4 (June 2015): 237–45. http://dx.doi.org/10.1016/j.syapm.2015.03.007.
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