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21.
22.
Bonacchi A Taddei ML Petrai I Efsen E Defranco R Nosi D Torcia M Rosini P Formigli L Rombouts K Zecchi S Milani S Pinzani M Laffi G Marra F 《Histology and histopathology》2008,23(3):327-340
The liver represents a site of expression of neurotrophins and their receptors. We have characterized the expression and intracellular localization of the nerve growth factor (NGF) receptor, Trk-A, in liver cells in vivo and in vitro. In both normal and fibrotic liver tissue, Trk-A immunostaining was present in different cell types, including parenchymal cells and cells of the inflammatory infiltrate. In hepatocytes and activated stellate cells (HSC), Trk-A showed a predominant nuclear localization, both in the presence and absence of injury. In cultured HSC, Trk-A was found to be functional, because exposure of the cells to recombinant NGF resulted in stimulation of cell migration and activation of intracellular signaling pathways, including Ras-ERK and PI3K/Akt. Remarkably, in cultured HSC, Trk-A staining was found constitutively in the nucleus. In these cells, Trk-A could be stained only by antibodies directed against the intracellular domain but not by those recognizing the extracellular portion of Trk-A suggesting that the intracellular portion of the receptor is the major determinant of nuclear Trk-A staining. In contrast to HSC, freshly isolated hepatocytes did not show any nuclear localization of the intracellular portion of Trk-A. In pheocromocytoma cells, nuclear staining for Trk-A was not present in conditions of serum deprivation, but could be induced by exposure to NGF or to a mixture of soluble mediators. We conclude that nuclear localization of the intracellular domain of Trk-A is observed constitutively in liver cells such as HSC, while in other cell types it could be induced in response to soluble factors. 相似文献
23.
Antonella Bonacci Elvira Brunelli Emilio Sperone Sandro Tripepi 《Zoologischer Anzeiger》2008,247(1):47-54
The morphology and development of the larval oral apparatus of Rana dalmatina, Bombina variegata, Bufo bufo, and Bufo viridis are described and compared using scanning electron microscopy. The species show different arrangements of the mouthparts. The small oral apparatus of R. dalmatina larvae has three labial tooth rows on the upper labium, while there are four tooth rows on the lower labium with a medial gap in row proximal to the mouth. The margins of the oral apparatus are defined by papillae that encircle the lower labium. B. variegata tadpoles have two upper labial tooth rows and three lower labial tooth rows that are uninterrupted, unlike the ones of R. dalmatina. The mouth is encircled by papillae that are larger than those of R. dalmatina. The oral discs of tadpoles of both B. bufo and B. viridis are similar. They are defined by two upper labial tooth rows (the second of which is interrupted by a medial gap) and by three lower tooth rows that differ in lengths in the two Bufo species. Both species develop papillae on the mouth angles and in two rows on the upper labium. Some morphological differences among the oral discs of R. dalmatina, B. variegata, B. bufo, and B. viridis tadpoles can be attributed to phylogenetic differences, but most can be related to their varying feeding habits and/or to their dietary specializations. 相似文献
24.
de Leon PM Campos VF Corcini CD Santos EC Rambo G Lucia T Deschamps JC Collares T 《Theriogenology》2012,77(1):21-27
The objective was to evaluate the effect of three cryopreservation methods on the in vitro maturation (IVM) and membrane integrity (MIn) of immature equine oocytes. An open pulled straw (OPS) method, a novel solid surface vitrification (SSV) process, and the addition of a synthetic ice blocker were evaluated. Compared with the control group (N = 269), the OPS (N = 159) and the SSV (N = 202) cryopreservation methods decreased both IVM (50.9 vs. 13.3 and 9.4%, respectively; P < 0.001) and MIn (76.6 vs. 31.1 and 33.7%; P < 0.001) of immature equine oocytes. However, inclusion of 0.1% ice blocker in the OPS vitrification process increased the rates of both IVM (30.5%; P < 0.01) and MIn (45.8%; P < 0.05) of the oocytes (N = 59). Including 0.1% ice blocker in the SSV process improved the IVM rate (20.9%; P < 0.05), whereas MIn remained compromised in this group (N = 67). However, increasing the concentration of the ice blocker (to 1.0%) in the cryopreservation methods did not significantly improve rates of IVM. In conclusion, the addition of a synthetic ice blocker (0.1%) to both cryopreservation processes significantly increased rates of both IVM and MIn of immature equine oocytes cryopreserved by OPS. 相似文献
25.
Rodolfo Jaffé Antonio Castilla Nathaniel Pope Vera Lucia Imperatriz-Fonseca Jean Paul Metzger Maria Cristina Arias Shalene Jha 《Conservation Genetics》2016,17(2):267-278
Pollination services are increasingly threatened by the loss and modification of natural habitats, posing a risk to the maintenance of both native plant biodiversity and agricultural production. In order to safeguard pollination services, it is essential to examine the impacts of habitat degradation on the population dynamics of key pollinators and identify potential “rescue pollinators” capable of persisting in these human-altered landscapes. Using a landscape genetic approach, we assessed the impact of landscape structure on genetic differentiation in the widely-distributed tropical stingless bee Trigona spinipes (Apidae: Meliponini) across agricultural landscape mosaics composed of coffee plantations and Atlantic forest fragments in southeastern Brazil. We genotyped 115 bees at 16 specific and highly polymorphic microsatellite loci, developed using next-generation sequencing. Our results reveal that T. spinipes is capable of dispersing across remarkably long distances, as we did not find genetic differentiation across a 200 km range, nor fine-scale spatial genetic structure. Furthermore, gene flow was not affected by forest cover, land cover, or elevation, indicating that reproductive individuals are able to disperse well through agricultural landscapes and across altitudinal gradients. We also found evidence of a recent population expansion, suggesting that this opportunistic stingless bee is capable of colonizing degraded habitats. Our results thus suggest that T. spinipes can persist in heavily-altered landscapes and can be regarded as a rescue pollinator, potentially compensating for the decline of other native pollinators in degraded tropical landscapes. 相似文献
26.
Phosphorylated p40PHOX as a negative regulator of NADPH oxidase 总被引:5,自引:0,他引:5
Lopes LR Dagher MC Gutierrez A Young B Bouin AP Fuchs A Babior BM 《Biochemistry》2004,43(12):3723-3730
The leukocyte NADPH oxidase catalyzes the production of O(2)(-) from oxygen at the expense of NADPH. Activation of the enzyme requires interaction of the cytosolic factors p47(PHOX), p67(PHOX), and Rac2 with the membrane-associated cytochrome b(558). Activation of the oxidase in a semirecombinant cell-free system in the absence of an amphiphilic activator can be achieved by phosphorylation of the cytosolic factor p47(PHOX) by protein kinase C. Another cytosolic factor, p40(PHOX), was recently shown to be phosphorylated on serine and threonine residues upon activation of NADPH oxidase, but both stimulatory and inhibitory roles were reported. In the present study, we demonstrate that the addition of phosphorylated p40(PHOX) to the cell-free system inhibits NADPH oxidase activated by protein kinase C-phosphorylated p47(PHOX), an effect not observed with the unphosphorylated p40(PHOX). Moreover phosphorylated p40(PHOX) inhibits the oxidase if added before or after full activation of the enzyme. Direct mutagenesis of protein kinase C consensus sites enables us to conclude that phosphorylation of threonine 154 is required for the inhibitory effect of p40(PHOX) to occur. Although the phosphorylated mutants and nonphosphorylated mutants are still able to interact with both p47(PHOX) and p67(PHOX) in pull-down assays, their proteolysis pattern upon thrombin treatment suggests a difference in conformation between the phosphorylated and nonphosphorylated mutants. We postulate that phosphorylation of p40(PHOX) on threonine 154 leads to an inhibitory conformation that shifts the balance toward an inhibitory role and blocks oxidase activation. 相似文献
27.
Paulo Roberto Melo-Sampaio Paulo Passos Antoine Fouquet Ana Lucia Da Costa Prudente Omar Torres-Carvajal 《分类学与生物多样性》2019,17(3):207-229
The Guiana Shield harbours one of the best preserved and largest extents of tropical forest on Earth and an immense biodiversity. The herpetofauna of this region remains poorly known. The species-rich snake genus Atractus contains ~140 species, many with complicated taxonomic histories, including A. schach. Examination of specimens in museums and newly collected material from French Guiana has allowed the illustration of hemipenial morphology for the first time and an expanded diagnosis. Concatenated molecular phylogenetic (mitochondrial and nuclear genes) and phenotypic (morphometrics, external and hemipenial morphology) analyses confirm non-monophyly of the A. flammigerus group and indicate that A. schach is a species complex with three new species described here. The geographic distribution of A. schach sensu stricto is restricted to Guiana, Surinam, and French Guiana north of Tumucumaque massif. Populations tentatively assigned to A. schach from the east from French Guiana in the Roura lowlands to Almeirim, and from central Amazonia between the Negro and Trombetas rivers in Brazil are also recognized as new species. Our results suggest that populations from south of the Amazon River are not conspecific with those from the Guiana Shield.
http://www.zoobank.org/urn:lsid:zoobank.org:pub:A7AE40BC-4716-4302-B3BE-1F43600B0A72 相似文献
28.
Michelino Di Rosa Corinne De Gregorio Giulia Malaguarnera Michele Tuttobene Filomena Biazzo Lucia Malaguarnera 《Molecular and cellular biochemistry》2013,374(1-2):73-80
Acidic mammalian chitinase (AMCase) and chitotriosidase (CHIT-1) are two active chitinases expressed in humans. The chitinase activity of AMCase was found to be causative in allergic inflammation and its expression was found to be induced by interleukin-13. CHIT1-1 is expressed by phagocytic cells and extremely high levels are seen in lysosomal storage diseases. Despite that AMCase expression in the inflammation is under investigation, little is known regarding its regulation during macrophages' full maturation and polarization. In this study, we compared AMCase and CHIT-1 modulation during monocyte to macrophage transition and polarization. Gene expression analysis was investigated by real-time PCR from mRNA of human monocytes obtained from buffy coat of healthy volunteers, from mRNA of polarized to classically activated macrophages (or M1), obtained by interferon (IFN)-γ and lipopolysaccharide (LPS) treatment, and from mRNA of alternatively activated macrophages (or M2) obtained by interleukin (IL)-4 exposure. Our results showed that the expression of AMCase and CHIT-1 were differently modulated in HMMs at different stage of maturation. The behavior of these two active chitinase suggests that in the immune response their role is complementary. 相似文献
29.
JoÃo B. Fernandes Otto R. Gottlieb Lucia M. Xavier 《Biochemical Systematics and Ecology》1978,6(1):55-58
The trunk wood of Aniba riparia (Nees) Mez (Lauraceae) contains flavokawin-B, (2S)-pinostrombin, (2S)-5, 7-di-O-methylpinocembrin, (2R, 3R)-5, 7-di-O-methylpinobanksin, izalpinin and 3,5, 7-tri-O-methylgalangin. Structural comparison of these flavonoids with the pyrones and neolignans, which characterized all previously examined Aniba spp., leads to a chemical classification of the genus. 相似文献
30.
Ly Diane Dongol Anjila Cuthbertson Peter Guy Thomas V. Geraghty Nicholas J. Sophocleous Reece A. Sin Lucia Turner Bradley J. Watson Debbie Yerbury Justin J. Sluyter Ronald 《Purinergic signalling》2020,16(1):109-122
Purinergic Signalling - The ATP-gated P2X7 ion channel has emerging roles in amyotrophic lateral sclerosis (ALS) progression. Pharmacological blockade of P2X7 with Brilliant Blue G can ameliorate... 相似文献