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51.
Early evolution of metazoan serine/threonine and tyrosine kinases: identification of selected kinases in marine sponges 总被引:13,自引:1,他引:13
The phylum Porifera (sponges) was the first to diverge from the common
ancestor of the Metazoa. In this study, six cDNAs coding for protein-
serine/threonine kinases (PS/TKs) are presented; they have been isolated
from libraries obtained from the demosponges Geodia cydonium and Suberites
domuncula and from the calcareous sponge Sycon raphanus. Sequence
alignments of the catalytic domains revealed that two major families of
PS/TK, the "conventional" (Ca(2+)-dependent) protein kinase C (PKC), the
cPKC subfamily, as well as the "novel" (Ca(2+)- independent) PKC (nPKC),
form two separate clusters. In each cluster, the sequence from S. raphanus
diverges first. To approach the question about the origin of
protein-tyrosine kinases (PTK), which are found only in Metazoa, we
analyzed two additional PS/TKs which have been cloned from S. domuncula:
the stress-responsive protein kinase (KRSvSD) and the
protein-kinase-C-related kinase (PRKvSD). The construction of the
phylogenetic tree, comprising the eight PS/TKs and the PTK cloned
previously from G. cydonium, revealed that the PTK derived from the branch
including the KRSvSD kinase. These data facilitate the first molecular
approach to elucidate the origin of metazoan PTK within the PS/TK
superfamily.
相似文献
52.
Sultmann H; Mayer WE; Figueroa F; Tichy H; Klein J 《Molecular biology and evolution》1995,12(6):1033-1047
The recent explosive adaptive radiation of cichlids in the great lakes of
Africa has attracted the attention of both morphologists and molecular
biologists. To decipher the phylogenetic relationships among the various
taxa within the family Cichlidae is a prerequisite for answering some
fundamental questions about the nature of the speciation process. In the
present study, we used the random amplification of polymorphic DNA (RAPD)
technique to obtain sequence differences between selected cichlid species.
We then designed specific primers based on these sequences and used them to
amplify template DNA from a large number of species by the polymerase chain
reaction (PCR). We sequenced the amplified products and searched the
sequences for indels and shared substitutions. We identified a number of
such characters at three loci-- DXTU1, DXTU2, and DXTU3--and used them for
phylogenetic and cladistic analysis of the relationships among the various
cichlid groups. Our studies assign an outgroup position to Neotropical
cichlids in relation to African cichlids, provide evidence for a
sister-group relationship of tilapiines to the haplochromines, group
Cyphotilapia frontosa with the lamprologines of Lake Tanganyika, place
Astatoreochromis alluaudi to an outgroup position with respect to other
haplochromines of Lakes Victoria and Malawi, and provide additional support
for the monophyly of the remaining Lake Victoria haplochromines and the
Lake Malawi haplochromines. The described approach holds great promise for
further resolution of cichlid phylogeny.
相似文献
53.
D. Ashley Robinson Susan K. Hollingshead James M. Musser Alan J. Parkinson David E. Briles Marilyn J. Crain 《Journal of molecular evolution》1998,47(2):222-229
The phylogenetic utility of the IS1167 insertion sequence was examined with restriction fragment length polymorphism (RFLP) analyses of a sample of 50, predominantly
invasive, capsular serotype 6B Streptococcus pneumoniae isolates previously characterized by multilocus enzyme electrophoresis (MLEE). The strains represented a genetically diverse
assemblage of 34 distinct clonotypes composed of 26 restriction fragment types and 23 multilocus enzyme types. All isolates
carried the IS1167 insertion sequence, with an average of 9.5 copies. The cross-classification of isolates based on RFLP and MLEE typing schemes
was 81% concordant. Phylogenetic analyses demonstrated a significant (P < 0.0001) association between strains of a given RFLP lineage with those of a given MLEE lineage. A significant correlation
(P < 0.00004) was also found between the proportion of restriction fragments shared by any given pair of isolates and their
genetic distances estimated from the MLEE data. Parity between the two genetic markers implied that the sampled isolates were
in linkage disequilibrium. The existence of nonrandom associations among genetic loci was confirmed by Monte Carlo analyses
of the MLEE data. These studies, thus, demonstrated that invasive pneumococcal isolates of a single capsule type recovered
on a regional scale can retain a largely clonal population structure over a period of 8 years. The ability to detect linkage
disequilibrium and generate relatively congruent dendrograms based on distance and parsimony methods suggested that the restriction
fragment data were robust to phylogenetic analysis.
Received: 20 May 1997 / Accepted: 20 November 1997 相似文献
54.
Resistance to Streptococcus pneumoniae is induced by a phosphocholine-protein conjugate 总被引:8,自引:0,他引:8
S Wallick J L Claflin D E Briles 《Journal of immunology (Baltimore, Md. : 1950)》1983,130(6):2871-2875
Previous studies demonstrated that naturally occurring antibodies to the pneumococcal cell wall hapten phosphocholine (PC) are important for the survival of mice against infection with Streptococcus pneumoniae, and that passively administered hybridoma antibody to PC results in added resistance. To determine if a PC-protein conjugate could elicit protective levels of anti-PC antibody, mice were immunized with PC-keyhole limpet hemocyanin (KLH) and tested for their ability to resist challenge with virulent S. pneumoniae. PC-KLH-immunized mice were observed to be resistant to 10- to 1000-fold more organisms than unimmunized control animals. The levels of protection were comparable to those induced with capsular polysaccharide antigens, but had the advantage of not being type-specific; immunization with PC-KLH protected mice against both type 1 and type 3 organisms. The induced immunity appeared to be antibody-mediated; it could be passively transferred with immune serum, and absorption of the immune serum with PC-Sepharose removed its protective capacity. Anti-PC antibodies in the serum of immunized mice were primarily IgM and IgG3 and possessed predominantly the T15 idiotype. Antibodies with these particular isotypes and this idiotype also arise after immunization with heat-killed rough pneumococci and recently were shown to be important in the resistance of mice to pneumococcal infection. 相似文献
55.
Abstract The mating behavior of cat flea, Ctenocepholides felis (Bouche) was studied on an artificial feeding device. Male and female can mate repeatedly with same partner or Merent ones. In the situation of male: female ratio of 1 :5, each mating lasted an average of 6.6 min, with a mean interval between matings at 2.5 min., compared to 11. 1 min and 12.1 min respectively in a cell with 5 males and 1 female. As many as 48 mating events were observed for one male during an 8 h period. One female mated 27 times in 7 h with 5 males in the same cell. Newly emerged males and females can not mate before blood meal and about 24 h blood feeding is rewuired for successful mating. Newly emerged males can not mate with fed females (fed for 48 h), but fed males can mate with newly emerged females who are feeding the blood. Significantly more male contacts and male-male mating attempts were observed after the paper treated with female extract was introduced into the cell. The paper contacts and mating attempts were 16.75–32.25 times and 15.75–31.38 times, respectively, on average during a period of 20 min when different doses (FE) of extract were provided. 相似文献
56.
57.
Prof. O. A. Schjeide W. E. Briles S. Holshouser D. G. Jones 《Cell and tissue research》1976,166(1):109-116
Summary The bulk of the yolk proteins and lipoproteins constituting the yolks of mature oocytes in birds are synthesized by the liver and transported via the plasma to the oocytes where they are incorporated by micropinocytosis. Evidence is presented indicating that oocytes of hens possessing a mutation identified by Jones, Briles, and Schjeide as a restricted ovulator gene fail to incorporate normal amounts and proportions of low density lipoproteins, lipovitellin and possibly other proteins making up the bulk of the yolk material. Plasma albumin is taken into the yolks but the other proteins synthesized by the liver for deposition within the oocytes accumulate in the plasma, attaining very high levels. The possible nature of the lock preventing normal deposition of the excluded yolk proteins is discussed. 相似文献
58.
Subclass restriction of murine anti-carbohydrate antibodies. 总被引:42,自引:0,他引:42
R M Perlmutter D Hansburg D E Briles R A Nicolotti J M Davie 《Journal of immunology (Baltimore, Md. : 1950)》1978,121(2):566-572
Examination of the subclass distribution of murine antibodies directed against groups A and C streptococcal carbohydrate, alpha-(1 leads to 3) dextran and phosphocholine yields the surprising observation that these carbohydrate antigens stimulate IgG responses largely restricted to the rare IgG3 subclass. This subclass restriction is particularly impressive in light of the low circulating levels of IgG3 in nonimmune mouse serum and the failure of a variety of other antigens including proteins and aromatic haptens to stimulate IgG3 antibody production. Attempts to alter the subclass restriction of antibodies with carbohydrate specificity by immunization with carbohydrate-coupled protein have been unsuccessful and indicate that immunoregulation of subclass expression probably occurs at the level of the antibody forming (B) cell. It is therefore conceivable that VH regions of murine immunoglobulins may be restricted to particular IgG subclasses. A similar type of subclass restriction has been reported in human and rat anti-carbohydrate antibodies. This recruitment of a minor immunoglobulin isotype by carbohydrate antigens in several species further supports the concept of immunoregulation at the level of subclass, and suggests that these and other mammals may share a structurally similar isotype with perhaps a common evolutionary origin. 相似文献
59.
60.
Miller MM Bacon LD Hala K Hunt HD Ewald SJ Kaufman J Zoorob R Briles WE 《Immunogenetics》2004,56(4):261-279
The first standard nomenclature for the chicken (Gallus gallus) major histocompatibility (B) complex published in 1982 describing chicken major histocompatibility complex (MHC) variability is being revised to include subsequent findings. Considerable progress has been made in identifying the genes that define this polymorphic region. Allelic sequences for MHC genes are accumulating at an increasing rate without a standard system of nomenclature in place. The recommendations presented here were derived in workshops held during International Society of Animal Genetics and Avian Immunology Research Group meetings. A nomenclature for B and Y (Rfp-Y) loci and alleles has been developed that can be applied to existing and newly defined haplotypes including recombinants. A list of the current standard B haplotypes is provided with reference stock, allele designations, and GenBank numbers for corresponding MHC class I and class II sequences. An updated list of proposed names for B recombinant haplotypes is included, as well as a list of over 17 Y haplotypes designated to date. 相似文献