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91.
Macquaridrilus mcmurtrieae n. sp. is described from Campbell Island. This resembles the only other species in the genus, Macquaridrilus bennettae Jamieson, 1968, in most aspects, but shows significant differences in the anatomy of its genitalia. In particular, the spermathecal pores are dorsal rather than lateral, the spermathecae lack diverticulae, the ejaculatory duct is more stout and muscular, the vas deferens is shorter relative to other organs and the anterior prostate is compact rather than elongate. The presence of a cuticular sperm canal appears to be an apomorphy for the genus. The new species was collected from streams and tarns across the island.http://zoobank.org/urn:lsid:zoobank.org:pub:652AF61D-CFB2-4D07-94C8-59E6FB549D5Fhttp://zoobank.org/urn:lsid:zoobank.org:act:984F2456-768D-48A1-87AD-4453768BAB8A 相似文献
92.
Sea urchin Hox genes: insights into the ancestral Hox cluster 总被引:3,自引:0,他引:3
We describe the Hox cluster in the radially symmetric sea urchin and
compare our findings to what is known from clusters in bilaterally
symmetric animals. Several Hox genes from the direct-developing sea urchin
Heliocidaris erythrogramma are described. CHEF gel analysis shows that the
Hox genes are clustered on a < or = 300 kilobase (kb) fragment of DNA,
and only a single cluster is present, as in lower chordates and other
nonvertebrate metazoans. Phylogenetic analyses of sea urchin, amphioxus,
Drosophila, and selected vertebrate Hox genes confirm that the H.
erythrogramma genes, and others previously cloned from other sea urchins,
belong to anterior, central, and posterior groups. Despite their radial
body plan and lack of cephalization, echinoderms retain at least one of the
anterior group Hox genes, an orthologue of Hox3. The structure of the
echinoderm Hox cluster suggests that the ancestral deuterostome had a Hox
cluster more similar to the current chordate cluster than was expected Sea
urchins have at least three Abd-B type genes, suggesting that Abd-B
expansion began before the radiation of deuterostomes.
相似文献
93.
94.
JC Biro 《Theoretical biology & medical modelling》2006,3(1):15-12
Background
Prediction of protein folding and specific interactions from only the sequence (ab initio) is a major challenge in bioinformatics. It is believed that such prediction will prove possible if Anfinsen's thermodynamic principle is correct for all kinds of proteins, and all the information necessary to form a concrete 3D structure is indeed present in the sequence. 相似文献95.
Iaci N. Soares Fabiana A. Caetano Jordan Pinder Bruna Roz Rodrigues Flavio H. Beraldo Valeriy G. Ostapchenko Chantal Durette Grace Schenatto Pereira Marilene H. Lopes Nicolle Queiroz-Hazarbassanov Isabela W. Cunha Paulo I. Sanematsu Sergio Suzuki Luiz F. Bleggi-Torres Caroline Schild-Poulter Pierre Thibault Graham Dellaire Vilma R. Martins Vania F. Prado Marco A. M. Prado 《Molecular & cellular proteomics : MCP》2013,12(11):3253-3270
Stress-inducible phosphoprotein 1 (STI1), a cochaperone for Hsp90, has been shown to regulate multiple pathways in astrocytes, but its contributions to cellular stress responses are not fully understood. We show that in response to irradiation-mediated DNA damage stress STI1 accumulates in the nucleus of astrocytes. Also, STI1 haploinsufficiency decreases astrocyte survival after irradiation. Using yeast two-hybrid screenings we identified several nuclear proteins as STI1 interactors. Overexpression of one of these interactors, PIAS1, seems to be specifically involved in STI1 nuclear retention and in directing STI1 and Hsp90 to specific sub-nuclear regions. PIAS1 and STI1 co-immunoprecipitate and PIAS1 can function as an E3 SUMO ligase for STI. Using mass spectrometry we identified five SUMOylation sites in STI1. A STI1 mutant lacking these five sites is not SUMOylated, but still accumulates in the nucleus in response to increased expression of PIAS1, suggesting the possibility that a direct interaction with PIAS1 could be responsible for STI1 nuclear retention. To test this possibility, we mapped the interaction sites between PIAS1 and STI1 using yeast-two hybrid assays and surface plasmon resonance and found that a large domain in the N-terminal region of STI1 interacts with high affinity with amino acids 450–480 of PIAS1. Knockdown of PIAS1 in astrocytes impairs the accumulation of nuclear STI1 in response to irradiation. Moreover, a PIAS1 mutant lacking the STI1 binding site is unable to increase STI1 nuclear retention. Interestingly, in human glioblastoma multiforme PIAS1 expression is increased and we found a significant correlation between increased PIAS1 expression and STI1 nuclear localization. These experiments provide evidence that direct interaction between STI1 and PIAS1 is involved in the accumulation of nuclear STI1. This retention mechanism could facilitate nuclear chaperone activity.Stress-inducible phosphoprotein I (STI1)1 is a conserved cochaperone protein that assists Hsp90 in managing client proteins, by mediating the transfer of proteins between Hsp70 and Hsp90 (1–3). STI1 contains several tetratricopeptide-repeat domains (TRP) that can serve as interaction modules with Hsp90 and Hsp70 (4). STI1 helps to drive the sequential steps involved in the Hsp90 chaperone machinery (5) and regulates the ATPase activity of Hsp90 (6, 7). STI1 is also secreted by distinct cells (8–12), using a noncanonical mechanism involving extracellular vesicles (11). Secreted STI1 can activate multiple signaling pathways in distinct cell types (8–10, 13–18).Elimination of STI1 in yeast sensitizes cells to Hsp90 inhibitors, but it is not by itself lethal (19). STI1 can also be eliminated in C. elegans, although it results in decreased life span (20). In contrast, STI1 mutant mice do not survive E10.5 and present several morphological defects, owing to decreased levels of several Hsp90-client proteins (21). Mouse embryonic fibroblasts obtained from STI1-deficient embryos also fail to thrive and present increased levels of the DNA damage marker γ-H2AX, suggestive of increased cellular stress (21). Hence, in mammals STI1 seems to play additional roles in cellular survival that are not yet fully understood.STI1 is abundantly expressed in the cytoplasm of cells, but can also be found in the Golgi (22), in vesicles and in multivesicular bodies (11). Moreover, this cochaperone has been shown to shuttle between the cytoplasm and the nucleus in cell lines (23). Cellular stress, arrest in G1/S phase of the cell cycle and phosphorylation are factors that seem to regulate STI1 nuclear localization (23, 24). Presumably nuclear STI1 can regulate chaperone activity, but whether it can interact with nuclear proteins is unknown.Previous experiments using cell lines have shown that knockdown of STI1 increases susceptibility of cells to irradiation (25). Whether changes in STI1 levels in primary differentiated cells, such as astrocytes, may affect their response to irradiation stress is unknown. This is of interest, as astrocytes, which can give rise to distinct tumor cells, are highly radioresistant (26). Indeed, astrocytes have a noncanonical DNA damage response (DDR) to irradiation (26). Here we show that STI1 undergoes nuclear translocation in astrocytes after γ-radiation-induced DNA damage. Moreover, astrocytes haploinsufficient for STI1 are more susceptible to cell death induced by irradiation. To understand potential mechanisms involved with STI1 nuclear retention, we have performed yeast-two hybrid screenings to identify STI1 nuclear partners. We identified protein inhibitor of activated STAT (PIAS1) as a direct interactor of STI1 and provide evidence that it acts as a small ubiquitin-like modifier (SUMO) E3 ligase for STI1. We show this interaction is involved with STI1 nuclear retention after irradiation. Interestingly, tissue microarray analysis demonstrated that higher PIAS1 levels are found in glioblastoma multiforme (GBM) when compared with non-neoplastic tissue. Furthermore, we uncovered a positive relationship between increased PIAS1 expression in GBMs and augmented STI1 nuclear localization. Our results reveal a novel mechanism by which increased expression of PIAS1, as observed in GBM, can increase the retention of nuclear STI1, a critical regulator of the chaperone machinery. 相似文献
96.
Jenny Davis Lien Sim Ross M. Thompson Adrian Pinder Jayne Brim Box Nicholas P. Murphy Fran Sheldon Alejandra Morán‐Ordóñez Paul Sunnucks 《Ecography》2018,41(2):375-387
Managing and restoring faunal diversity across large areas requires an understanding of the roles of connectivity and dispersal in driving community patterns. We sought to determine the influence of connectivity, water regime, water source, geographical location, and dispersal traits on patterns of aquatic invertebrate diversity across a continent‐wide arid biome. We compiled data on freshwater invertebrate assemblages from sites spanning the breadth of arid Australia. Univariate analyses (analysis of variance and rarefaction) revealed that alpha and gamma diversity across sites decreased as latitude increased. Multivariate analyses (ordination and analysis of similarity) revealed that community composition had considerable fidelity to geographic regions. Hydrological connectivity was strongly associated with riverine community composition although water rarely flowed (often less than annually). Hydrologically isolated sites (springs and rockholes) supported communities that were markedly dissimilar to hydrologically connected sites, and to each other. We investigated the influence of dispersal on diversity patterns by examining distance decay relationships for each of four dispersal trait groups (obligate aquatic and passive, weak, and strong aerial dispersers) on the basis of geodesic (shortest path) distances between pairs of sites and Mantel tests. We did not detect clear differences between dispersal traits and distance decay relationships at the continental scale, even for the two groups with the lowest dispersal ability (obligate aquatics and passive dispersers). Our results suggest that the loss of hydrological connectivity from water developments in arid lands (for example, the impoundment of intermittent rivers) is likely to affect macroinvertebrates. However, the exact flow mechanisms underlying such changes remain to be determined. 相似文献
97.
98.
99.
The 2-micron plasmid of the budding yeast Saccharomyces cerevisiae encodes copy-number amplification and partitioning systems that enable the plasmid to persist despite conferring no advantage to its host. Plasmid partitioning requires interaction of the plasmid Rep1 and Rep2 proteins with each other and with the plasmid-partitioning locus STB. Here we demonstrate that Rep1 stability is reduced in the absence of Rep2, and that both Rep proteins are sumoylated. Lysine-to-arginine substitutions in Rep1 and Rep2 that inhibited their sumoylation perturbed plasmid inheritance without affecting Rep protein stability or two-hybrid interaction between Rep1 and Rep2. One-hybrid and chromatin immunoprecipitation assays revealed that Rep1 was required for efficient retention of Rep2 at STB and that sumoylation-deficient mutants of Rep1 and Rep2 were impaired for association with STB. The normal co-localization of both Rep proteins with the punctate nuclear plasmid foci was also lost when Rep1 was sumoylation-deficient. The correlation of Rep protein sumoylation status with plasmid-partitioning locus association suggests a theme common to eukaryotic chromosome segregation proteins, sumoylated forms of which are found enriched at centromeres, and between the yeast 2-micron plasmid and viral episomes that depend on sumoylation of their maintenance proteins for persistence in their hosts. 相似文献
100.
Apoptosis can be detected in attached colonic adenocarcinoma HT29 cells using annexin V binding, but not by TUNEL assay or sub-G0 DNA content 总被引:4,自引:0,他引:4
BACKGROUND: Induction of apoptosis in adherent cell lines is associated with cell loss from the substratum. In this study the adenocarcinoma cell line, HT29, treated with indomethacin (400microM) has been employed as a model system to demonstrate how flow cytometric analysis can be used to quantify the changes that occur during this process. METHODS: Adherent and floating cell populations have been analyzed independently for effects on cell number, cell cycle characteristics and apoptosis using TUNEL assay and Annexin V binding. In addition apoptosis has been assessed using DNA laddering and morphology. RESULTS: Apoptosis was detected in adherent cells treated with indomethacin using Annexin V binding but not by other techniques employed in this study. In contrast, analysis of "floating" cells revealed the presence of apoptotic cells both in control and indomethacin treated cells using all the techniques employed. However quantification by flow cytometry showed that a significantly higher proportion of control "floaters" were late apoptotic/necrotic rather than apoptotic. DISCUSSION: The data here illustrate the need to interpret measures of apoptosis in adherent cell lines with care and the value of using flow cytometric techniques in the quantitative evaluation of the process. 相似文献