The breeding system of Eichhorniaazurea (Pontederiaceae) has been described as being both self- and heteromorphic incompatible based on crossing experiments performed on plants grown in an experimental garden. We studied the breeding system of tristylous E. azurea population under natural conditions in the Pantanal wetlands, Brazil. Controlled pollinations were conducted using 35 individuals of each floral morph. Legitimate pollinations produced more fruits than self- and illegitimate pollinations, except for the mid-styled morph which was highly self- and heteromorphic compatible. The number of seeds per fruit was higher under legitimate pollinations than in the other treatments, but self- and illegitimate pollinations produced more fruits and seeds in the Pantanal than for individuals of E. azurea in other populations. The higher fruit and seed production resulting from legitimate pollinations corroborate previous studies, but self-compatibility of mid-styled plants was not previously reported. Overall results indicate a partially self- and heteromorphic compatible system for this species in the Pantanal. 相似文献
Hypothalamic insulin inhibits food intake, preventing obesity. High-fat feeding with polyunsaturated fats may be obesogenic, but their effect on insulin action has not been elucidated. The present study evaluated insulin hypophagia and hypothalamic signaling after central injection in rats fed either control diet (15% energy from fat) or high-fat diets (50% energy from fat) enriched with either soy or fish oil. Soy rats had increased fat pad weight and serum leptin with normal body weight, serum lipid profile and peripheral insulin sensitivity. Fish rats had decreased body and fat pad weight, low leptin and corticosterone levels, and improved serum lipid profile. A 20-mU dose of intracerebroventricular (ICV) insulin inhibited food intake in control and fish groups, but failed to do so in the soy group. Hypothalamic protein levels of IR, IRS-1, IRS-2, Akt, mTOR, p70S6K and AMPK were similar among groups. ICV insulin stimulated IR tyrosine phosphorylation in control (68%), soy (36%) and fish (34%) groups. Tyrosine phosphorylation of the pp185 band was significantly stimulated in control (78%) and soy (53%) rats, but not in fish rats. IRS-1 phosphorylation was stimulated only in control rats (94%). Akt serine phosphorylation was significantly stimulated only in control (90%) and fish (78%) rats. The results showed that, rather than the energy density, the fat type was a relevant aspect of high-fat feeding, since blockade of hypothalamic insulin signal transmission and insulin hypophagia was promoted only by the high-fat soy diet, while they were preserved in the rats fed with the high-fat fish diet. 相似文献
The emergence of a multidrug-resistant HIV-1 strain and the toxicity of anti-HIV-1 compounds approved for clinical use are the most significant problems facing antiretroviral therapies. Therefore, it is crucial to find new agents to overcome these issues. In this study, we synthesized a series of new oxoquinoline acyclonucleoside phosphonate analogues (ethyl 1-[(diisopropoxyphosphoryl)methyl]-4-oxo-1,4-dihydroquinoline-3-carboxylates 3a-3k), which contained different substituents at the C6 or C7 positions of the oxoquinoline nucleus and an N1-bonded phosphonate group. We subsequently investigated these compounds' in vitro inhibitory effects against HIV-1-infected peripheral blood mononuclear cells (PBMCs). The most active compounds were the fluoro-substituted derivatives 3f and 3g, which presented excellent EC(50) values of 0.4±0.2 μM (3f) and 0.2±0.005 μM (3g) and selectivity index values (SI) of 6240 and 14675, respectively. 相似文献
A 6.5-kilobase murine genomic DNA fragment isolated by Levenson et al. (Levenson, R., Racaniello, V., Albritton, L., and Housman, D. (1984) Proc. Natl. Acad. Sci. U.S.A. 81, 1489-1493) (called the ouabain resistance gene) has been shown to produce ouabain resistance in primate cells. Preliminary sequence information has revealed no homology with the coding sequence of the Na,K-ATPase. We have introduced this murine sequence into monkey and murine cells in an attempt to characterize its mechanism of action. In our experiments, transfection of this DNA fragment is associated with the low frequency (1 in 8 x 10(5) cells) appearance of ouabain-resistant clones of CV1, COS, and NIH 3T3 cells, an event not seen in control transfections. Characterization of a new clone of ouabain-resistant CV1 cells (called OR8 cells) revealed a 5-fold increase in the IC50 for ouabain inhibition of rubidium uptake and a 10-fold increase in cell survival on ouabain. Although the murine sequence was detectable in Southern blots of ouabain-resistant cells soon after transfection, this exogenous DNA was rapidly lost despite continued exposure to ouabain. Furthermore, we were unable to detect message expression by this genomic sequence in any of the three cell types tested. Instead, we found that all three ouabain-resistant cell lines exhibited point mutations in a domain of the alpha-subunit that has been implicated in ouabain sensitivity (H1-H2). One of these mutations (Asp121-Asn121 in OR8 cells) has been previously reported to cause ouabain resistance (Price, E.M., Rice, D.A., and Lingrel, J.B. (1989) J. Biol. Chem. 264, 21902-21906). Other novel mutations in the H2 transmembrane domain were also detected. We postulate that the "ouabain resistance gene" is important in the early selection process on ouabain but that the permanent ouabain-resistant phenotype is due to a stable mutation in one allele of the alpha-subunit of the Na,K-ATPase. 相似文献
A study of bacterial surface oligosaccharides were investigated among
different strains of Neisseria gonorrhoeae to correlate structural features
essential for binding to the MAb 2C7. This epitope is widely expressed and
conserved in gonococcal isolates, characteristics essential to an effective
candidate vaccine antigen. Sample lipooligosaccharides (LOS), was prepared
by a modification of the hot phenol-water method from which de-O-acetylated
LOS and oligosaccharide (OS) components were analyzed by ES-MS-CID-MS and
ES-MSnin a triple quadrupole and an ion trap mass spectrometer,
respectively. Previously documented natural heterogeneity was apparent from
both LOS and OS preparations which was admixed with fragments induced by
hydrazine and mild acid treatment. Natural heterogeneity was limited to
phosphorylation and antenni extensions to the alpha-chain. Mild acid
hydrolysis to release OS also hydrolyzed the beta(1-->6) glycosidic
linkage of lipid A. OS structures were determined by collisional and
resonance excitation combined with MS and multistep MSn which provided
sequence information from both neutral loss, and nonreducing terminal
fragments. A comparison of OS structures, with earlier knowledge of MAb
binding, enzyme treatment, and partial acid hydrolysis indicates a generic
overlapping domain for 2C7 binding. Reoccurring structural features include
a Hepalpha(1-->3)Hepbeta(1-->5)KDO trisaccharide core branched on the
nonreducing terminus (Hep-2) with an alpha(1-->2) linked GlcNAc
(gamma-chain), and an alpha-linked lactose (beta-chain) residue. From the
central heptose (Hep-1), a beta(1-->4) linked lactose (alpha-chain),
moiety is required although extensions to this residue appear unnecessary.
相似文献
Abstract: The modulation by adenosine analogues and endogenous adenosine of the electrically evoked release of [3H]acetylcholine ([3H]ACh) was compared in subslices of the three areas of the rat hippocampus (CA1, CA3, and dentate gyrus). The mixed A1/A2 agonist 2-chloroadenosine (CADO; 2–10 µM) inhibited, in a concentration-dependent manner, the release of [3H]ACh from the three hippocampal areas, being more potent in the CA1 and CA3 areas than in the dentate gyrus. The inhibitory effect of CADO (5 µM) on [3H]ACh release was prevented by the A1 antagonist 1,3-dipropyl-8-cyclopentylxanthine (DPCPX; 50 nM) in the three hippocampal areas and was converted in an excitatory effect in the CA3 and dentate gyrus areas. The A2A agonist CGS-21680 (30 nM) produced a greater increase of the evoked release of [3H]ACh in the CA3 than in the dentate gyrus areas, whereas no consistent effect was found in the CA1 area or in the whole hippocampal slice. The excitatory effect of CGS-21680 (30 nM) in the CA3 area was prevented by the adenosine receptor antagonist 3,7-dimethyl-1-propargylxanthine (10 µM). Both adenosine deaminase (2 U/ml) and DPCPX (250 nM) increased the evoked release of [3H]ACh in the CA1 and CA3 areas but not in the dentate gyrus. The amplitude of the effect of DPCPX and adenosine deaminase was similar in the CA1 area, but in the CA3 area DPCPX produced a greater effect than adenosine deaminase. It is concluded that the electrically evoked release of [3H]ACh in the three areas of the rat hippocampus can be differentially modulated by adenosine. In the CA1 area, only A1 inhibitory receptors modulate ACh release, whereas in the CA3 area, both A2A excitatory and A1 inhibitory adenosine receptors modulate ACh release. In the dentate gyrus, both A1 inhibitory and A2A excitatory adenosine receptors are present, but endogenous adenosine does not activate them. 相似文献
Pontoporia blainvillei (Gervais & d’Orbigny, 1844), the franciscana dolphin, is the most endangered small cetacean in the Western South Atlantic. It is an endemic species with a coastal and estuarine distribution that has been divided into four Franciscana Management Areas (FMAs). We used the mitochondrial DNA control region to conduct a phylogeographic analysis to evaluate the population structure of the franciscana and the influence of paleoceanographic events on its biogeographic history. We found nine populations along the entire distribution (ΦST?=?0.41, ΦCT?=?0.38, p?<?10–5), with estimated migration rates resulting in less than one female per generation. Populations from FMAIII and FMAIV in the south (including the Río de La Plata Estuary) showed higher long-term migration rates and effective population sizes than northern populations. The phylogeographic analysis supports the franciscana origin in the Río de La Plata Estuary, with further dispersal south and northwards. The first lineage split happened around 2.5 Ma, with lineage radiation throughout the Pleistocene until recent fragmentation events shaped current-day populations. We suggest that Pleistocene glaciations influenced the dispersion and population structure of the franciscana. Specifically, that the shift of the Brazil-Malvinas Confluence drove the dispersion northwards. Then, low sea-level periods caused either the isolation in estuarine refugia or local extinctions, followed by re-colonizations.
The authors report a clinical case of an isolated oral histoplasmosis in a hemodialysis patient that presented with fever of unknown origin and had an unremarkable physical examination. During the investigation, a Gallium scan showed uptake in the oral cavity and soon after the oral cavity examination revealed a granulomatous lesion on the tooth 26. Histopathologic findings were compatible with histoplasmosis. The treatment regimen included liposomal amphotericin B followed by itraconazole consolidation therapy, and side effects did not occur. Both clinical evolution and outcome were favorable. Oral histoplasmosis in a non-immunosuppressed patient is extremely rare. 相似文献
Light activation of photosensitizing dyes in presence of molecular oxygen generates highly cytotoxic reactive oxygen species leading to cell inactivation. Nucleic acids are molecular targets of this photodynamic action but not considered the main cause of cell death. The in vivo effect of the photodynamic process on the intracellular nucleic acid content of Escherichia coli and Staphylococcus warneri was evaluated herein.Two cationic porphyrins (Tetra-Py+-Me and Tri-Py+-Me-PF) were used to photoinactivate E. coli (5.0 μM; 108 cells mL?1) and S. warneri (0.5 μM; 108 cells mL?1) upon white light irradiation at 4.0 mW cm?2 for 270 min and 40 min, respectively. Total nucleic acids were extracted from photosensitized bacteria after different times of irradiation and analyzed by agarose gel electrophoresis. The double-stranded DNA was quantified by fluorimetry and the porphyrin binding to bacteria was determined by spectrofluorimetry.E. coli was completely photoinactivated with both porphyrins (5.0 μM), whereas S. warneri was only completely inactivated by Tri-Py+-Me-PF (0.5 μM). The hierarchy of nucleic acid changes in E. coli was in the order: 23S rRNA > 16S rRNA > genomic DNA. The nucleic acids of S. warneri were extensively reduced after 5 min with Tri-Py+-Me-PF but almost unchanged with Tetra-Py+-Me after 40 min of irradiation. The amount of Tri-Py+-Me-PF bound to E. coli after washing the cells is higher than Tetra-Py+-Me and the opposite was observed for S. warneri. The binding capacity of the photosensitizers is not directly related to the PDI efficiency or nucleic acid reduction and this reduction occurs in parallel with the decrease of surviving cells. 相似文献