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891.
Field investigations of the home range size and emigration pattern of wild helmeted guineafowl ( Numida meleagris galeata Pallas) from 1992 to 1995 showed that home range size (±95% confidence limits (CL) ) varied with season from 3·6±1·5 km2 for the dry seasons to 3·1±1·5 km2 for the rainy seasons. Home range size varied depending on whether it was estimated with data for adult males, adult females or young birds, with a higher home range size for young birds, closely followed by adult males. Group size (±95%CL) varied by month, and was highest between March and April (47·0±8·1 birds/group) and lowest in August 9·0±5·1 birds/group). More young birds (±95%CL) (36·8±19·6%) dispersed than adult males (21·1±1·9%) or adult females (13·5±1·8%). There was a highly significant positive correlation between group size and the number of birds emigrating from the group. There was also a significant negative correlation between the weights of birds at tagging and the percentage that emigrated during the first year of study but not later. This is suggested to be linked to the high number of young birds emigrating, since they weigh relatively less than adults. The lack of correlation between body weight and number of birds emigrating a year or later after birds were tagged was thought to be due to the fact that birds tagged while young attained adult weight within a year. 相似文献
892.
Post-transcriptional β-1,3-glucanase gene silencing involves increased transcript turnover that is translation-independent 总被引:1,自引:1,他引:0
893.
The microdialysis technique was utilized to study the local effects of D1 and D2 family type dopamine (DA) receptor (R) ligands on the in vivo release of endogenous glutamate (GLU) and aspartate (ASP) from rat substantia nigra (SN). Addition to the dialysis perfusion solution of either D1-R and D2-R agonists, such as SKF-38393 (50 and 100 M) and Quinpirole (5 and 10 M), resulted in dose-dependent increases in extracellular concentrations of GLU and ASP, respectively. The SKF-38393 and Quinpirole-induced effects were reduced by SCH-23390 (0.5 M), a D1-R antagonist, and by Spiperone (1.0 M), a D2-R antagonist, respectively. However, SCH-23390 and Spiperone did increase GLU and ASP extracellular concentrations. Local infusion with Tetrodotoxin (TTX) (1.0 M), a blocker of voltage-dependent Na+ channels, increased basal extracellular levels of GLU. In addition, co-infusion of TTX and SKF-38393 evoked increases in extracellular GLU levels higher than those observed after SKF-38393 alone. Finally, chemical lesions of nigral DA cells with 6-OH-DA increased the basal extracellular levels of GLU. It is proposed that the release of GLU and ASP from SN may be regulated by D1- and D2-receptors present in this basal ganglia structure. In addition, part of the D1 receptors present in SN might be located presynaptically on GLU-containing nerve endings. 相似文献
894.
Sara Santamaria Maria Cristina Gagliani Grazia Bellese Silvia Marconi Anastasia Lechiara Martina Dameri Cinzia Aiello Erica Tagliatti Patrizio Castagnola Katia Cortese 《The journal of histochemistry and cytochemistry》2021,69(7):461
Breast cancers (BCa) with ERBB2 amplification show rapid tumor growth, increased disease progression, and lower survival rate. Deregulated intracellular trafficking and extracellular vesicle (EVs) release are mechanisms that support cancer progression and resistance to treatments. Neratinib (NE) is a Food and Drug Administration–approved pan-ERBB inhibitor employed for the treatment of ERBB2+ BCa that blocks signaling and causes survival inhibition. However, the effects of NE on ERBB2 internalization, its trafficking to multivesicular bodies (MVBs), and the release of EVs that originate from these organelles remain poorly studied. By confocal and electron microscopy, we observed that low nanomolar doses of NE induced a modest ERBB2 internalization along with an increase of clathrin-mediated endocytosis and of the CD63+ MVB compartment in SKBR-3 cells. Furthermore, we showed in the culture supernatant two distinct EV subsets, based on their size and ERBB2 positivity: small (30–100 nm) ERBB2− EVs and large (>100 nm) ERBB2+ EVs. In particular, we found that NE increased the overall release of EVs, which displayed a reduced ERBB2 positivity compared with controls. Taken together, these results provide novel insight into the effects of NE on ERBB2+ BCa cells that may lead to a reduction of ERBB2 potentially transferred to distant target cells by EVs: 相似文献
895.
Mir Derikvand M Sierra JB Ruel K Pollet B Do CT Thévenin J Buffard D Jouanin L Lapierre C 《Planta》2008,227(5):943-956
Cinnamoyl-CoA reductase 1 (CCR1, gene At1g15950) is the main CCR isoform implied in the constitutive lignification of Arabidopsis thaliana. In this work, we have identified and characterized two new knockout mutants for CCR1. Both have a dwarf phenotype and a delayed senescence. At complete maturity, their inflorescence stems display a 25–35% decreased
lignin level, some alterations in lignin structure with a higher frequency of resistant interunit bonds and a higher content
in cell wall-bound ferulic esters. Ferulic acid-coniferyl alcohol ether dimers were found for the first time in dicot cell
walls and in similar levels in wild-type and mutant plants. The expression of CCR2, a CCR gene usually involved in plant defense, was increased in the mutants and could account for the biosynthesis of lignins in
the CCR1-knockout plants. Mutant plantlets have three to four-times less sinapoyl malate (SM) than controls and accumulate some feruloyl
malate. The same compositional changes occurred in the rosette leaves of greenhouse-grown plants. By contrast and relative
to the control, their stems accumulated unusually high levels of both SM and feruloyl malate as well as more kaempferol glycosides.
These findings suggest that, in their hypolignified stems, the mutant plants would avoid the feruloyl-CoA accumulation by
its redirection to cell wall-bound ferulate esters, to feruloyl malate and to SM. The formation of feruloyl malate to an extent
far exceeding the levels reported so far indicates that ferulic acid is a potential substrate for the enzymes involved in
SM biosynthesis and emphasizes the remarkable plasticity of Arabidopsis phenylpropanoid metabolism. 相似文献
896.
Jaubert M Vuillet L Hannibal L Adriano JM Fardoux J Bouyer P Bonaldi K Fleischman D Giraud E Verméglio A 《Journal of bacteriology》2008,190(17):5824-5831
897.
An urokinase receptor antagonist that inhibits cell migration by blocking the formyl peptide receptor 总被引:1,自引:0,他引:1
Bifulco K Longanesi-Cattani I Gargiulo L Maglio O Cataldi M De Rosa M Stoppelli MP Pavone V Carriero MV 《FEBS letters》2008,582(7):1141-1146
Urokinase receptor (uPAR) plays a key role in physiological and pathological processes sustained by an altered cell migration. We have developed peptides carrying amino acid substitutions along the Ser(88)-Arg-Ser-Arg-Tyr(92) (SRSRY) uPAR chemotactic sequence. The peptide pyro glutamic acid (pGlu)-Arg-Glu-Arg-Tyr-NH2 (pERERY-NH(2)) shares the same binding site with SRSRY and competes with N-formyl-Met-Leu-Phe (fMLF) for binding to the G-protein-coupled N-formyl-peptide receptor (FPR). pERERY-NH(2) is a dose-dependent inhibitor of both SRSRY- and fMLF-directed cell migration, and prevents agonist-induced FPR internalization and fMLF-dependent ERK1/2 phosphorylation. pERERY-NH(2) is a new and potent uPAR inhibitor which may suggest the generation of new pharmacological treatments for pathological conditions involving increased cell migration. 相似文献
898.
Mugnol KC Ando RA Nagayasu RY Faljoni-Alario A Brochsztain S Santos PS Nascimento OR Nantes IL 《Biophysical journal》2008,94(10):4066-4077
The alternative low-spin states of Fe(3+) and Fe(2+) cytochrome c induced by SDS or AOT/hexane reverse micelles exhibited the heme group in a less rhombic symmetry and were characterized by electron paramagnetic resonance, UV-visible, CD, magnetic CD, fluorescence, and Raman resonance. Consistent with the replacement of Met(80) by another strong field ligand at the sixth heme iron coordination position, Fe(3+) ALSScytc exhibited 1-nm Soret band blue shift and epsilon enhancement accompanied by disappearance of the 695-nm charge transfer band. The Raman resonance, CD, and magnetic CD spectra of Fe(3+) and Fe(2+) ALSScytc exhibited significant changes suggestive of alterations in the heme iron microenvironment and conformation and should not be assigned to unfold because the Trp(59) fluorescence remained quenched by the neighboring heme group. ALSScytc was obtained with His(33) and His(26) carboxyethoxylated horse cytochrome c and with tuna cytochrome c (His(33) replaced by Asn) pointing out Lys(79) as the probable heme iron ligand. Fe(3+) ALSScytc retained the capacity to cleave tert-butylhydroperoxide and to be reduced by dithiothreitol and diphenylacetaldehyde but not by ascorbate. Compatible with a more open heme crevice, ALSScytc exhibited a redox potential approximately 200 mV lower than the wild-type protein (+220 mV) and was more susceptible to the attack of free radicals. 相似文献
899.
Baraldi PG Pavani MG Leung E Moorman AR Varani K Vincenzi F Borea PA Romagnoli R 《Bioorganic & medicinal chemistry letters》2006,16(5):1402-1404
Among the adenosine A(1) allosteric enhancers reported so far, compound (2-amino-4,5,6,7-tetrahydrobenzo[b]thiophen-3-yl)-(4-chlorophenyl)-methanone 1 (named T-62) has shown biological properties similar to those of PD 81,723, the reference A(1) allosteric enhancer and it has been more fully pharmacologically investigated. The preparation of the radiolabelled form of compound 1 and its characterization by saturation binding experiments are reported. These studies allowed us to demonstrate for the first time the existence of a specific, allosteric site on the A(1) receptor. 相似文献
900.
Romagnoli R Baraldi PG Moorman AR Iaconinoto MA Carrion MD Cara CL Tabrizi MA Preti D Fruttarolo F Baker SP Varani K Borea PA 《Bioorganic & medicinal chemistry letters》2006,16(21):5530-5533
The microwave-assisted aromatization method has been used for the synthesis of a series of novel thieno[2,3-c]pyridines. This rapid method produces compounds in good yield within minutes in comparison with conventional heating method. The synthesized molecules have been evaluated as a potential new series of allosteric enhancers acting at the adenosine A(1) receptor. In a functional assay, one compound (3h) showed activity comparable with that of reference compound PD 81,723. 相似文献