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Lisa Dovere Stefania Fera Margherita Grasso Dante Lamberti Cesare Gargioli Barbara Muciaccia Anna Maria Lustri Mario Stefanini Elena Vicini 《PloS one》2013,8(4)
In mammals, the biological activity of the stem/progenitor compartment sustains production of mature gametes through spermatogenesis. Spermatogonial stem cells and their progeny belong to the class of undifferentiated spermatogonia, a germ cell population found on the basal membrane of the seminiferous tubules. A large body of evidence has demonstrated that glial cell line-derived neurotrophic factor (GDNF), a Sertoli-derived factor, is essential for in vivo and in vitro stem cell self-renewal. However, the mechanisms underlying this activity are not completely understood. In this study, we show that GDNF induces dose-dependent directional migration of freshly selected undifferentiated spermatogonia, as well as germline stem cells in culture, using a Boyden chamber assay. GDNF-induced migration is dependent on the expression of the GDNF co-receptor GFRA1, as shown by migration assays performed on parental and GFRA1-transduced GC-1 spermatogonial cell lines. We found that the actin regulatory protein vasodilator-stimulated phosphoprotein (VASP) is specifically expressed in undifferentiated spermatogonia. VASP belongs to the ENA/VASP family of proteins implicated in actin-dependent processes, such as fibroblast migration, axon guidance, and cell adhesion. In intact seminiferous tubules and germline stem cell cultures, GDNF treatment up-regulates VASP in a dose-dependent fashion. These data identify a novel role for the niche-derived factor GDNF, and they suggest that GDNF may impinge on the stem/progenitor compartment, affecting the actin cytoskeleton and cell migration. 相似文献
225.
Jian Lin Zhiwei Peng Gunuk Wang Dante Zakhidov Eduardo Larios Miguel Jose Yacaman James M. Tour 《Liver Transplantation》2014,4(10)
A facile route is developed to boost the electrocatalytic activity of WS2 by chemically unzipping WS2 nanotubes to form WS2 nanoribbons (NRs) with increased edge content. Analysis indicates that the hydrogen evolution reaction activity is strongly associated with the number of exposed active edge sites. The formation of WS2 NRs is an effective route for controlling the electrochemical properties of the 2D dichalcogenides, enabling their application in electrocatalysis. 相似文献
226.
Structural investigation of bilayers formed by 1-palmitoyl-2-oleoylphosphatidylnucleosides
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Bilayers of palmitoyl-oleoylphosphatidylnucleoside derivatives (1-palmitoyl-2-oleoyl-phosphatidyl-adenosine and 1-palmitoyl-2-oleoyl-phosphatidyl-uridine) were synthesized and investigated in the low-water content regime by a combination of neutron diffraction and Fourier transform infrared linear dichroism (LD-FTIR). Attention was focused on the modulation of structural properties operated by the presence of nucleic acid bases (either adenosine or uridine, a purine and a pyrimidine that are complementary in RNA). Base substitution causes major differences in phase behavior of the phospholipids, i.e., water sorption from a controlled humidity atmosphere and smectic periodicity. The profile of scattering length density can be inferred from five diffraction orders for 1-palmitoyl-2-oleoyl-phosphatidyl-uridine lamellar phase. 1-Palmitoyl-2-oleoyl-phosphatidyl-adenosine is characterized by lower and less ready hydration, giving rise to a powder-like sample. A linear dichroism FTIR investigation on the same lamellar phases was undertaken with the purpose of gathering details at the submolecular level on different portions of the molecule. 1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine bilayers were also investigated with the same technique for the sake of comparison. Besides a confirmation of the diffraction data interpretation, FTIR has provided evidence that the same chemical groups at the bilayer interface (namely the sugar-phosphate) have a different orientation depending on whether the base is a purine or a pyrimidine. A very simple geometrical optimization agrees with this observation. This indicates that a different pattern of base interaction is operating in the two cases and that base substitution acts as a modulator of the phase properties. 相似文献
227.
Barbara Biondi Dante Goldin Elisa Giannini Roberta Lattanzi Lucia Negri Pietro Melchiorri Luigi Ciocca Raniero Rocchi 《International journal of peptide research and therapeutics》2006,12(2):139-144
Syntheses are described of the nociceptin (1–13) amide [NC(1–13)-NH2] and of several analogues in which either one or both the phenylalanine residues (positions 1 and 4), the arginine residues (positions 8 and 12) and the alanine residues (positions 7 and 11) have been replaced by N-benzyl-glycine, N-(3-guanidino-propyl)-glycine and β-alanine, respectively. The preparation is also described of NC(1–13)-NH2 analogues in which either galactose or N-acetyl-galactosamine are β-O-glycosidically linked to Thr5 and/or to Ser10. Preliminary pharmacological experiments on mouse vas deferens preparations showed that Phe4, Thr5, Ala7 and Arg8 are crucial residues for OP4 receptor activation. Manipulation of Phe1 yielded peptides endowed with antagonist activity but [Nphe1] NC(1–13)-NH2 acted as an antagonist still possessing weak agonist activity. Introduction of the βAla residue either in position 7 or 11 of the [Nphe1] NC(1–13)-NH2 sequence, abolished any residual agonist activity and [Nphe1, βAla7] NC(1–13)-NH2 and [Nphe1, βAla11] NC(1–13)-NH2 acted as competitive antagonists only. Modification of both Ala7 and Ala11 abolished the antagonist activity of [Nphe1]NC(1–13)-NH2 probably by hindering receptor binding. Changes at positions 10 and 11 gave analogues still possessing agonist activity. [Ser(βGal)10] NC(1–13)-NH2 displayed an activity comparable with that of NC(1–13)-NH2, [Ser(βGalNAc)10] NC(1–13)-NH2 and [βAla11] NC(1–13)-NH2 were five and 10 times less active, respectively.The α-amino acid residues are of the l-configuration. Standard abbreviations for amino acid derivatives and peptides are according to the suggestions of the IUPAC-IUB Commission on Biochemical Nomeclature (1984), Eur. J. Biochem. 138, 9–37. Abbreviations listed in the guide published in (2003), J. Peptide Sci. 9, 1–8 are used without explanation. 相似文献
228.
Organic fertilizers alter the composition of pathogens and arbuscular mycorrhizal fungi in maize roots
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Ricardo Aguilar Yazmin Carreón‐Abud Dante López‐Carmona John Larsen 《Journal of Phytopathology》2017,165(7-8):448-454
Roots of agricultural crops, including maize, are hosts of different microorganisms, many beneficial, like plant growth and health‐promoting arbuscular mycorrhizal fungi (AMF), as well as pathogens including Pythium, Polymyxa and Microdochium. To improve crop nutrition and health, profound knowledge is required regarding how agricultural practices affect field populations of root‐associated microorganisms. Hence, the objective of this work was to evaluate the effect of crop genotype and organic fertilizers on the plant growth performance of maize and their root‐associated microorganisms. The experiment was conducted as a fully factorial greenhouse pot experiment with maize cultivars (two land races and two hybrids) and organic fertilizers (green manure, cow manure and compost) as the two main factors. Plants were harvested 8 weeks after sowing. In general, the different maize cultivars responded similarly to the applications of the organic fertilizers. Cow manure and compost increased plant growth, whereas green manure had limited effect on plant growth. Root colonization with AMF was reduced by green manure with rape. Infection with the root pathogens Pythium and Polymyxa was reduced by all organic fertilizers, whereas in contrast, infection with Microdochium increased with the majority of the organic fertilizers applied. In conclusion, both maize genotype and organic fertilizers affect the abundance of AMF and root pathogens in maize, which should be considered when developing management strategies of these root‐inhabiting microorganisms. 相似文献
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Dante Camarillo Ravelo Octavio Loera Corral Ignacio González-Martínez Wilberth Chan Cupul 《Preparative biochemistry & biotechnology》2020,50(6):592-597
AbstractThe laccase (Lac), manganese peroxidases (MnP), and lignin peroxidase enzymes produced by basidiomycete have been studied due to their potential in bioremediation, therefore, in this study, degradation of diclofenac (DCF), sulfamethoxazole (SMX), indomethacin (IND), gemfibrozil (GFB), and bezafibrate (BZF) by enzymes produced by Trametes maxima, Pleurotus sp., and Pycnosporus sanguineus grown in culture was evaluated. The degradation of drugs can mainly be attributed to MnP because a correlation between the activity of this enzyme and the degree of removal was found. The specific activity of Lac did not show correlation with drug removal, while lignin peroxidase was not expressed. Trametes maxima showed the highest specific activity of MnP (387.6?±?67.4?U/mg) and efficiency removal 90.2% of DCF, 72.62% of SMX, 60.76% of IND, 43.39% of GFB, and 32.59% of BZF) followed by Pleurotus sp. with specific activity of MnP of 55.9?±?8.5?U/mg and 89.47% of DCF, 47.61% of GFB and 73% of IND were removed, P. sanguineus had the lowest specific activity of 18?±?1.3?U/mg and was able to remove only 42% of SMX and 10.59% of IND. In order to prove that MnP remove drugs instead of Lac, the pure Lac was tested and only degraded DCF. 相似文献