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121.
Variability in the trophic position of larval fish in a coastal pelagic ecosystem based on stable isotope analysis 总被引:1,自引:0,他引:1
We used stable isotopes of carbon (C) and nitrogen (N) to investigatethe trophic position of six species of larval fish in the pelagicecosystem of coastal Newfoundland. Isotope profiles from phytoplankton,net plankton and macrozooplankton were consistent with previousstudies. All species of larval fish showed a length-dependentshift in 13C that indicates a move to a pelagic diet from thecombined pelagic and demersal eating habits of the adult spawners.The trophic position of four larval fish species (American plaice,yellowtail flounder, cunner, radiated shanny) was consistentwith them feeding primarily on copepods, as expected from stomachcontent analysis. The 15N-based trophic position of larval witchflounder and capelin indicates that they feed significantlyon phytoplankton and heterotrophic protists from the microbialloop, respectively; this evidence contrasts with stomach contentanalysis. Although links between larval fish and the microbialloop are not considered as common as is the link with crustaceanzooplankton, this and other studies challenge the long-heldbelief that marine fish larvae feed effectively exclusivelyon copepods. 相似文献
122.
Cytokine receptors and B cell functions. I. Recombinant soluble receptors specifically inhibit IL-1- and IL-4-induced B cell activities in vitro 总被引:10,自引:0,他引:10
C R Maliszewski T A Sato T Vanden Bos S Waugh S K Dower J Slack M P Beckmann K H Grabstein 《Journal of immunology (Baltimore, Md. : 1950)》1990,144(8):3028-3033
IL-1 and IL-4 are important mediators of B cell growth and differentiation. The cell-surface receptors for these cytokines have recently been cloned and recombinant soluble receptors have been produced that bind their respective ligand. The ability of soluble forms of the murine IL-1R (sIL-1R) and IL-4R (sIL-4R) to inhibit B cell functions in vitro was examined. Proliferation of B cells treated with anti-Ig plus IL-1 or IL-4 was inhibited by the appropriate soluble receptor. sIL-4R also inhibited IL-4-dependent B cell differentiation as measured by: induction of IgG1 and IgE secretion by LPS blasts, down-regulation of IgG3 secretion by LPS blasts, increased Ia expression, and increased Fc epsilon R (CD23) expression. The inhibitory effects of the soluble receptors were found to be highly specific in that sIL-4R had no effect on IL-1-induced B cell activity and sIL-1R had no effect on IL-4 activity, further demonstrating the existence of two independent pathways of B cell activation directed by IL-1 and IL-4. 相似文献
123.
124.
Xiaohua Song Ana Lopez-Campistrous Lucy Sun Nancy A. Dower Noemi Kedei Jing Yang Jessica S. Kelsey Nancy E. Lewin Tim E. Esch Peter M. Blumberg James C. Stone 《PloS one》2013,8(8)
Ingenol-3–angelate (I3A) is a non-tumor promoting phorbol ester-like compound identified in the sap of Euphoria peplus. Similar to tumor promoting phorbol esters, I3A is a diacylglycerol (DAG) analogue that binds with high affinity to the C1 domains of PKCs, recruits PKCs to cellular membranes and promotes enzyme activation. Numerous anti-cancer activities have been attributed to I3A and ascribed to I3A’s effects on PKCs. We show here that I3A also binds to and activates members of the RasGRP family of Ras activators leading to robust elevation of Ras-GTP and engagement of the Raf-Mek-Erk kinase cascade. In response to I3A, recombinant proteins consisting of GFP fused separately to full-length RasGRP1 and RasGRP3 were rapidly recruited to cell membranes, consistent with direct binding of the compound to RasGRP’s C1 domain. In the case of RasGRP3, IA3 treatment led to positive regulatory phosphorylation on T133 and activation of the candidate regulatory kinase PKCδ. I3A treatment of select B non-Hodgkin’s lymphoma cell lines resulted in quantitative and qualitative changes in Bcl-2 family member proteins and induction of apoptosis, as previously demonstrated with the DAG analogue bryostatin 1 and its synthetic analogue pico. Our results offer further insights into the anticancer properties of I3A, support the idea that RasGRPs represent potential cancer therapeutic targets along with PKC, and expand the known range of ligands for RasGRP regulation. 相似文献
125.
A molecular phylogeny for aplocheiloid fishes (Atherinomorpha, Cyprinodontiformes): the role of vicariance and the origins of annualism 总被引:2,自引:0,他引:2
Annual aplocheiloid killifish embryos possess a rare ability among
vertebrates to enter stages of developmental arrest (diapause) when
subjected to adverse environmental conditions. Previous morphological
analyses have presented disparate hypotheses regarding the evolution of the
intriguing life history associated with this phenomenon. We present a novel
hypothesis of aplocheiloid relationships based on 1,009 bp of sequence data
from three mitochondrial genes (cytochrome b, 12S rRNA, and 16S rRNA).
Phylogenetic analysis using maximum parsimony, neighbor- joining, and
maximum likelihood produce strongly congruent topologies. Our data confirm
the monophyly of the Neotropical family Rivulidae, while demonstrating a
paraphyletic Old World assemblage. The basal sister group position of
Indo-Malaysian and Madagascaran taxa relative to a monophyletic South
American/African dichotomy strongly indicates the role of vicariance in the
diversification of these fishes in spite of their definition as secondary
freshwater fish. The distribution of annualism onto this topology implies a
single early origin for this suite of characters, prior to the divergence
of South American and African taxa. If so, then annualism has since been
lost several times during the evolution of genera now residing in permanent
aquatic habitats. Paleoclimatic knowledge complements this scenario based
on molecular characters.
相似文献
126.
The balance between IL-1 and its naturally occurring inhibitor IL-1 receptor antagonist (IL-1ra) is critical in determining the inflammatory response. Four splice variants of the IL-1ra gene have been identified; one secreted (sIL-1ra) and three intracellular (icIL-1ra1-3). The biological roles of the intracellular isoforms remain largely unclear. We wished to determine whether icIL-1ra1 had intracellular functions regulating IL-1 signalling. Signalling was determined using an NF-kappaB reporter assay measuring induction of the IL-8 promoter in transfected cells. Over-expression of icIL-1ra1 in HeLa cells had no effect on IL-1 stimulated IL-8 activity. In contrast over-expression of sIL-ra significantly attenuated IL-1 activity. In addition, transfection of icIL-1ra1 in HeLa cells did not cause inhibition of IL-8 promoter activity following over-expression of the IL-1 signalling components MyD88, IRAK-1, TRAF-6, Ikappakappabeta or RelA. This implies that icIL-1ra1 does not act to alter IL-1 mediated intracellular signalling in this system. We investigated whether ATP and/or over-expression of the P2X7 receptor caused icIL-1ra1 inhibition of IL-1beta mediated IL-8 reporter activation, by permitting its release. In HeLa cells, no effect of icIL-1ra1 was observed in ATP stimulated and/or P2X7 transfected cells, compared to a significant inhibition in sIL-1ra transfected cells. However, in endothelial cells stimulated with ATP, the released fraction was effective in attenuating IL-1beta activation of the IL-8 reporter. These results suggest that icIL-1ra1 does not act at an intracellular level to alter IL-1 mediated signalling, and is effective in inhibiting IL-1 responses only when released in an ATP-dependent and cell type specific manner. 相似文献
127.
Wilson Lim Emmanuel Siddig Kimberly Eadie Bertrand Nyuykonge Sarah Ahmed Ahmed Fahal Annelies Verbon Sandra Smit Wendy WJ van de Sande 《PLoS neglected tropical diseases》2020,14(12)
BackgroundEumycetoma is a neglected tropical disease most commonly caused by the fungus Madurella mycetomatis. Identification of eumycetoma causative agents can only be reliably performed by molecular identification, most commonly by species-specific PCR. The current M. mycetomatis specific PCR primers were recently discovered to cross-react with Madurella pseudomycetomatis. Here, we used a comparative genome approach to develop a new M. mycetomatis specific PCR for species identification.MethodologyPredicted-protein coding sequences unique to M. mycetomatis were first identified in BLASTCLUST based on E-value, size and presence of orthologues. Primers were then developed for 16 unique sequences and evaluated against 60 M. mycetomatis isolates and other eumycetoma causing agents including the Madurella sibling species. Out of the 16, only one was found to be specific to M. mycetomatis.ConclusionWe have discovered a predicted-protein coding sequence unique to M. mycetomatis and have developed a new species-specific PCR to be used as a novel diagnostic marker for M. mycetomatis. 相似文献
128.
129.
Hunting for genes by functional screens 总被引:1,自引:0,他引:1
Advances in high throughput sequencing technologies have led to an explosion of sequence information available for today's researchers. Efforts in the emerging next phase of the genomic era are focusing on the assignment of function to genes uncovered by genome sequencing programs. The main approaches include high throughput mutagenesis, predictions based on homology in primary sequence, microarray and proteomics. Despite the variety of strategies applied, only 30% of predicted human genes have any function assigned. There is a need, therefore, for additional tools to overcome some of the limitations of existing techniques. In this review we discuss some recent developments and their impact on gene function annotation, especially as they relate to the elucidation of signalling cascades activated by cytokines and growth factors. 相似文献
130.
Lukas Mangnus Hanna W. van Steenbergen Elisabet Lindqvist Elisabeth Brouwer Monique Reijnierse Tom WJ Huizinga Peter K. Gregersen Ewa Berglin Solbritt Rantap??-Dahlqvist Désirée van der Heijde Annette HM van der Helm-van Mil 《Arthritis research & therapy》2015,17(1)
IntroductionThe western population is ageing. It is unknown whether age at diagnosis affects the severity of Rheumatoid Arthritis (RA), we therefore performed the present study.Method1,875 RA-patients (7,219 radiographs) included in five European and North-American cohorts (Leiden-EAC, Wichita, Umeå, Groningen and Lund) were studied on associations between age at diagnosis and joint damage severity. In 698 Leiden RA-patients with 7-years follow-up it was explored if symptom duration, anti-citrullinated-peptide-antibodies (ACPA), swollen joint count (SJC) and C-reactive-protein (CRP) mediated the association of age with joint damage. Fifty-six other RA-patients of the EAC-cohort underwent baseline MRIs of wrist, MCP and MTP-joints; MRI-inflammation (RAMRIS-synovitis plus bone marrow edema) was also evaluated in mediation analyses. Linear regression and multivariate normal regression models were used.ResultsAnalysis on the five cohorts and the Leiden-EAC separately revealed 1.026-fold and 1.034-fold increase of radiographic joint damage per year increase in age (β=1.026, 1.034, both p<0.001); this effect was present at baseline and persisted over time. Age correlated stronger with baseline erosion-scores compared to joint space narrowing (JSN)-scores (r=0.38 versus 0.29). Symptom duration, ACPA, SJC and CRP did not mediate the association of age with joint damage severity. Age was significantly associated with the MRI-inflammation-score after adjusting for CRP and SJC (β=1.018, p=0.027). The association of age with joint damage (β=1.032, p=0.004) decreased after also including the MRI-inflammation-score (β=1.025, p=0.021), suggesting partial mediation.ConclusionRA-patients presenting at higher age have more severe joint damage; this might be partially explained by more severe MRI-detected inflammation at higher age.