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61.
Life-history characteristics of the double-ended pipefish, Syngnathoides biaculeatus (Bloch), were investigated to determine growth rate, degree of sexual dimorphism, size at maturity, and reproductive biology. Growth rates of wild juveniles and adults calculated from monthly progression of length-frequency modes ranged from 0.8mmd–1 (fish lengths 120–145mm standard length (SL)) in summer to 0.2mmd–1 in winter (185–200mm SL). Growth of laboratory-reared juveniles up to 63d old was greater, ranging from 0.8 to 2.3mmd-1. The von Bertalanffy growth constant K was estimated at 0.0076d- 1, or 2.8year–1. Morphological differentiation between the sexes based upon abdominal pattern was possible for fish larger than 120mm SL, with females possessing a zigzag pattern on the abdomen. The association between this pattern and sex was confirmed by histological gonad analysis. Males were significantly longer than females during four of seven seasons examined, and a 1:1 sex ratio was determined for all seasons except autumn when the ratio was female biased. The breeding season was marked by the appearance of pregnant males between October and April, and during courtship both species exhibited increased pigmentation. The minimum paternal size at maturity was 185mm, the maximum length recorded 260mm. Clutch size ranged between 60 and 200 eggs, with a mean of 153. Ovaries had a sequential pattern of egg development, resulting in egg batches that approximated the number of eggs carried by brooding males. Additionally, all eggs in a brood were at the same developmental stage. This suggests that one female provides all of the eggs for one male per breeding event in a monogamous mating system. 相似文献
62.
Xanthones from the bark of Garcinia merguensis 总被引:1,自引:0,他引:1
The bark of Garcinia merguensis yielded 10 xanthones, merguenone, 1,5-dihydroxy-6'-methyl-6'-(4-methyl-3-pentenyl)-pyrano(2',3':3,2)-xanthone, subelliptenone H, 8-deoxygartanin, rheediaxanthone A, morusignin G, 6-deoxyjacareubin, 1,3,5-trihydroxy-4,8-di(3-methylbut-2-enyl)-xanthone, rheediachromenoxanthone and 6-deoxyisojacareubin. The structure of merguenone was determined using spectroscopic techniques, mainly 1D and 2D NMR spectroscopy. 相似文献
63.
Fairhurst AM Connolly JE Hintz KA Goulding NJ Rassias AJ Yeager MP Rigby W Wallace PK 《Arthritis research & therapy》2003,5(4):R214-R225
Tumor necrosis factor (TNF) has been implicated in the development and pathogenicity of infectious diseases and autoimmune disorders, such as septic shock and arthritis. The zinc-finger protein tristetraprolin (TTP) has been identified as a major regulator of TNF biosynthesis. To define its intracellular location and examine its regulation of TNF, a quantitive intracellular staining assay specific for TTP was developed. We establish for the first time that in peripheral blood leukocytes, expression of endogenous TTP is confined to the cytoplasm. Baseline expression of TTP was higher in monocytes than in lymphocytes or neutrophils. After in vitro incubation with lipopolysaccharide (LPS), leukocyte TTP levels increased rapidly, peaking after approximately 2 hours. Monocytes showed the greatest response to LPS stimulation and lymphocytes the least. TTP levels were also studied in leukocytes isolated from healthy volunteers infused with a bolus dose of LPS. TTP expression and initial upregulation in response to LPS infusion were consistent with the in vitro data. Neutrophil TTP levels responded first, reaching an initial peak within 1 hour, monocyte levels peaked next at 2 hours, followed by lymphocytes at 4 hours. This response paralleled plasma TNF levels, which peaked 2 hours after infusion and were no longer detectable after 12 hours. A second rise in intracellular TTP levels, which did not parallel plasma TNF levels, was observed in all leukocyte populations, starting 12 hours after infusion. These data establish the cytoplasmic location of TTP, supporting a major role for this protein in regulating TNF production, and suggest that TTP levels are not regulated solely by TNF. 相似文献
64.
Taylor RW Wardell TM Connolly BA Turnbull DM Lightowlers RN 《Nucleic acids research》2001,29(16):3404-3412
Mutations in mitochondrial DNA (mtDNA) cause a spectrum of human pathologies, which predominantly affect skeletal muscle and the central nervous system. In patients, mutated and wild-type mtDNAs often co-exist in the same cell (mtDNA heteroplasmy). In the absence of pharmacological therapy, a genetic strategy for treatment has been proposed whereby replication of mutated mtDNA is inhibited by selective hybridisation of a nucleic acid derivative to the single-stranded replication intermediate, allowing propagation of the wild-type genome and correction of the associated respiratory chain defect. Previous studies have shown the efficacy of this anti-genomic approach in vitro, targeting pathogenic mtDNA templates with only a single point mutation. Pathogenic molecules harbouring deletions, however, present a more difficult problem. Deletions often occur at the site of two short repeat sequences (4–13 residues), only one of which is retained in the deleted molecule. With the more common larger repeats it is therefore difficult to design an anti-genomic molecule that will bind selectively across the breakpoint of the deleted mtDNA. To address this problem, we have used linker-substituted oligodeoxynucleotides to bridge the repeated residues. We show that molecules can be designed to bind more tightly to the deleted as compared to the wild-type mtDNA template, consistent with the nucleotide sequence on either side of the linker co-operating to increase binding affinity. Furthermore, these bridging molecules are capable of sequence-dependent partial inhibition of replication in vitro. 相似文献
65.
Myers NB Harris MR Connolly JM Lybarger L Yu YY Hansen TH 《Journal of immunology (Baltimore, Md. : 1950)》2000,165(10):5656-5663
The endoplasmic reticulum protein tapasin is considered to be a class I-dedicated chaperone because it facilitates peptide loading by proposed mechanisms such as peptide editing, endoplasmic reticulum retention of nonpeptide-bound molecules, and/or localizing class I near the peptide source. Nonetheless, the primary functions of tapasin remain controversial as do the relative dependencies of different class I molecules on tapasin for optimal peptide loading and surface expression. Tapasin dependencies have been addressed in previous studies by transfecting different class I alleles into tapasin-deficient LCL721.220 cells and then monitoring surface expression and Ag presentation to T cells. Indeed, by these criteria, class I alleles have disparate tapasin-dependencies. In this study, we report a novel and more direct method of comparing tapasin dependency by monitoring the ratio of folded vs open forms of the different mouse class I heavy chains, L(d), K(d), and K(b). Furthermore, we determine the amount of de novo heavy chain synthesis required to attain comparable expression in the presence vs absence of tapasin. Our findings show that tapasin dramatically improves peptide loading of all three of these mouse molecules. 相似文献
66.
Inhibition of cholesteryl ester transfer protein by substituted dithiobisnicotinic acid dimethyl ester: involvement Of a critical cysteine 总被引:1,自引:0,他引:1
Hope HR Heuvelman D Duffin K Smith C Zablocki J Schilling R Hegde S Lee L Witherbee B Baganoff M Bruce C Tall AR Krul E Glenn K Connolly DT 《Journal of lipid research》2000,41(10):1604-1614
SC-71952, a substituted analog of dithiobisnicotinic acid dimethyl ester, was identified as a potent inhibitor of cholesteryl ester transfer protein (CETP). When tested in an in vitro assay, the concentration of SC-71952 required for half-maximal inhibition was 1 microm. The potency of SC-71952 was enhanced 200-fold by preincubation of the inhibitor with CETP, and was decreased 50-fold by treatment with dithiothreitol. Analogs of SC-71952 that did not contain a disulfide linkage were less potent, did not display time dependency, and were not affected by dithiothreitol treatment. Kinetic and biochemical characterization of the inhibitory process of CETP by SC-71952 suggested that the inhibitor initially binds rapidly and reversibly to a hydrophobic site on CETP. With time, the bound inhibitor irreversibly inactivates CETP, presumably by reacting with one of the free cysteines of CETP. Liquid chromatography/mass spectroscopy (LC/MS) analyses of tryptic digests of untreated or SC-71952-inactivated CETP was used to identify which cysteine(s) were potentially involved in the time-dependent, irreversible component of inactivation by the inhibitor. One disulfide bond, Cys143-Cys184, was unaffected by treatment with the inhibitor. Inactivation of CETP by SC-71952 correlated with a progressive decrease in the abundance of free Cys-13 and Cys-333. Conversion of Cys-13 to alanine had no effect on the rapid reversible component of inactivation by SC-71952. However, it abolished the time-dependent enhancement in potency seen with the inhibitor when using wild-type CETP. These data indicate that Cys-13 is critical for the irreversible inactivation of CETP by SC-71952 and provides support for the structural model that places Cys-13 near the neutral lipid-binding site of CETP. 相似文献
67.
Dentener PR Lewthwaite SE Bennett KV Maindonald JH Connolly PG 《Journal of economic entomology》2000,93(2):519-525
Morality responses were determined for 5th-instar lightbrown apple moth, Epiphyas postvittana (Walker), in the presence and absence of apples to immersion in ethanol solutions and exposure to ethanol vapor at a range of concentrations, treatment times, and temperatures. Ethanol may have caused an initial knock-down effect in E. postvittana larvae because there was a trend for larval mortality to reduce with increased periods between treatment and assessment time when immersed at 20 degrees C in 30 or 50% ethanol solutions. Mortality for larvae immersed on apples in a range of ethanol concentrations was higher than for larvae in the absence of apples. Increasing treatment temperature from 20 to 45 degrees C during ethanol immersion significantly increased larval mortality. During ethanol vapor exposure, longer treatment times were required to achieve 99% E. postvittana mortality for larvae on apples compared with those in the absence of apples. 相似文献
68.
Reovirus-induced apoptosis requires activation of transcription factor NF-kappaB 总被引:5,自引:0,他引:5
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Connolly JL Rodgers SE Clarke P Ballard DW Kerr LD Tyler KL Dermody TS 《Journal of virology》2000,74(7):2981-2989
69.
Presence or absence of N-acetylneuraminic acid (Neu5Ac) can change a
sialylated glycoprotein's serum half-life and possibly its function. We
evaluated the linearity, sensitivity, reproducibility, and accuracy of a
HPAEC/PAD method to determine its suitability for routine simultaneous
analysis of Neu5Ac and N-glycolylneuraminic acid (Neu5Gc). An effective
internal standard for this analysis is 3-deoxy-d-glycero-d-
galacto-2-nonulosonic acid (KDN). We investigated the effect of the Au
working electrode recession and determined that linear range and
sensitivity were dependent on electrode recession. Using an electrode that
was 350 &mgr;m recessed from the electrode block, the minimum detection
limits of Neu5Ac, KDN, and Neu5Gc were 2, 5, and 2 pmol, respectively, and
were reduced to 1, 2, and 0.5 pmol using a new electrode. The response of
standards was linear from 10 to 500 pmol (r2>0.99) regardless of
electrode recession. When Neu5Ac, KDN, and Neu5Gc (200 pmol each) were
analyzed repetitively for 48 h, area RSDs were <3%. Reproducibility was
unaffected when injections of glycoprotein neuraminidase and acid
digestions were interspersed with standard injections. Area RSDs of Neu5Ac
and Neu5Gc improved when the internal standard was used. We determined the
precision and accuracy of this method for both a recessed and a new working
electrode by analyzing Neu5Ac and Neu5Gc contents of bovine fetuin and
bovine and human transferrins. Results were consistent with published
values and independent of the working electrode. The sensitivity,
reproducibility, and accuracy of this method make it suitable for direct
routine analysis of glycoprotein Neu5Ac and Neu5Gc contents.
相似文献
70.
Bovine pancreatic deoxyribonuclease I (DNase I) is a nuclease of relatively low specificity which interacts with DNA in the minor groove. No contacts are made between the protein and the major groove of the nucleic acid. DNase I is structurally homologous to exonuclease III, a DNA-repair enzyme with multiple activities. One of the main differences between the two enzymes is the presence of an additional alpha-helix in exonuclease III, in a position suggestive of interaction with the major groove of DNA. Recombinant DNA techniques have been used to add 14 amino acids, comprising the 10 amino acids of the exonuclease III alpha-helix flanked by a glycine rich region, to DNase I. The polypeptide has been inserted after serine 174, an amino acid on the surface of DNase I corresponding to the location of the extra alpha-helix in exonuclease III. The recombinant protein, DNase-exohelix, has been purified and its catalytic activities towards DNA investigated. The recombinant protein demonstrated a high selectivity for endonucleolytic cleavage at abasic sites in DNA, a property of exonuclease III but not native DNase I. Thus the insertion of 14 amino acids at Ser174, converts DNase I to an exonuclease III-like enzyme with DNA-repair properties. 相似文献