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Juliana Foresti Milani Joecildo Francisco Rocha Simone de Pádua Teixeira 《Trees - Structure and Function》2012,26(3):769-775
Although studies have addressed the chemical analysis and the biological activity of oleoresin in species of Copaifera, the cellular mechanisms of oleoresin production, storage, and release have rarely been investigated. This study detailed
the distribution, ontogeny, and ultrastructure of secretory cavities and canals distributed in leaf and stem, respectively,
of Copaifera trapezifolia, a Brazilian species included in a plant group of great economic interest. Axillary vegetative buds, leaflets, and portions
of stem in primary and secondary growth were collected and processed in order to study the anatomy, histolocalization of substances,
and ultrastructure. Secretory cavities are observed in the foliar blade and secretory canals in the petiolule and stem. They
are made up of a uniseriate epithelium delimiting an isodiametric or elongated lumen. Biseriate epithelium is rarely observed
and is a novelty for Leguminosae. Cavities and canals originate from ground meristem cells and the lumen is formed by schizogenesis.
The content of the cavities and canals of both stem and leaf is oily and resinous, which suggests that the oleoresin could
be extracted from the leaf instead of the stem. Phenolic compounds are also detected in the epithelial cell cytoplasm. Cavities
and canals in the beginning of developmental stages have polarized epithelial cells. The cytoplasm is rich in smooth and rough
endoplasmic reticula connected to vesicles or plastids. Smooth and rough endoplasmic reticulum and plastids were found to
be predominant in the epithelial cells of the secretory cavities and canals of C. trapezifolia. Such features testify the quantities of oleoresin found in the lumen and phenolic compounds in the epithelial cell cytoplasm
of these glands. Other studies employing techniques such as correlative light electron microscopy could show the vesicle traffic
and the compartmentalization of the produced substances in such glands. 相似文献
135.
Ghiselli F Milani L Chang PL Hedgecock D Davis JP Nuzhdin SV Passamonti M 《Molecular biology and evolution》2012,29(2):771-786
136.
137.
The crystallographic structure of oxygenated trHbN from Mycobacterium tuberculosis showed an extended heme distal site hydrogen-bonding network that includes Y(B10), Q(E11), and the bound O(2) (Milani, M., et al. (2001) EMBO J. 20, 3902-3909). In the present work, we analyze the effects that substitutions at the B10 and E11 positions exert on the heme and its coordinated ligands, using steady-state resonance Raman spectroscopy, absorption spectroscopy and X-ray crystallography. Our results show that (1) residues Y(B10) and Q(E11) control the binding and the ionization state of the heme-bound water molecules in ferric trHbN and are important in keeping the sixth coordination position vacant in deoxy trHbN; (2) residue Q(E11) plays a role in maintaining the integrity of the proximal Fe-His bond in deoxy trHbN; (3) in wild-type oxy-trHbN, the size and hydrogen-bonding capability of residue E11 is important to sustain proper interaction between Y(B10) and the heme-bound O(2); (4) CO-trHbN is in a conformational equilibrium, where either the Y(B10) or the Q(E11) residue interacts with the heme-bound CO; and (5) Y(B10) and Q(E11) residues control the conformation (and likely the dynamics) of the protein matrix tunnel gating residue F(E15). These findings suggest that the functional processes of ligand binding and diffusion are controlled in trHbN through the dynamic interaction of residues Y(B10), Q(E11), F(E15), and the heme ligand. 相似文献
138.
Federica Cossu Mario Milani Eloise Mastrangelo Patrice Vachette Daniele Lecis Domenico Delia Vincenzo Rizzo Pierfausto Seneci Carlo Scolastico Martino Bolognesi 《Journal of molecular biology》2009,392(3):630-596
XIAP is an apoptotic regulator protein that binds to the effector caspases -3 and -7 through its BIR2 domain, and to initiator caspase-9 through its BIR3 domain. Molecular docking studies suggested that Smac-DIABLO may antagonize XIAP by concurrently targeting both BIR2 and BIR3 domains; on this basis bivalent Smac-mimetic compounds have been proposed and characterized. Here, we report the X-ray crystal structure of XIAP-BIR3 domain in complex with a two-headed compound (compound 3) with improved efficacy relative to its monomeric form. A small-angle X-ray scattering study of XIAP-BIR2BIR3, together with fluorescence polarization binding assays and compound 3 cytotoxicity tests on HL60 leukemia cell line are also reported. The crystal structure analysis reveals a network of interactions supporting XIAP-BIR3/compound 3 recognition; moreover, analytical gel-filtration chromatography shows that compound 3 forms a 1:1 stoichiometric complex with a XIAP protein construct containing both BIR2 and BIR3 domains. On the basis of the crystal structure and small-angle X-ray scattering, a model of the same BIR2-BIR3 construct bound to compound 3 is proposed, shedding light on the ability of compound 3 to relieve XIAP inhibitory effects on caspase-9 as well as caspases -3 and -7. A molecular modeling/docking analysis of compound 3 bound to cIAP1-BIR3 domain is presented, considering that Smac-mimetics have been shown to kill tumor cells by inducing cIAP1 and cIAP2 ubiquitination and degradation. Taken together, the results reported here provide a rationale for further development of compound 3 as a lead in the design of dimeric Smac mimetics for cancer treatment. 相似文献
139.
Alma Balestrazzi Silvia Botti Samantha Zelasco Stefania Biondi Cinzia Franchin Paolo Calligari Milvia Racchi Adelaide Turchi Guido Lingua Graziella Berta Daniela Carbonera 《Plant cell reports》2009,28(8):1179-1192
Marker-free transgenic white poplar (Populus alba L., cv ‘Villafranca’) plants, expressing the PsMT
A1
gene from Pisum sativum for a metallothionein-like protein, were produced by Agrobacterium tumefaciens-mediated transformation. The 35SCaMV-PsMT
A1
-NosT cassette was inserted into the ipt-type vector pMAT22. The occurrence of the abnormal ipt-shooty phenotype allowed the visual selection of transformants, while the yeast site-specific recombination R/RS system was
responsible for the excision of the undesired vector sequences with the consequent recovery of normal marker-free transgenic
plants. Molecular analyses confirmed the presence of the 35SCaMV-PsMT
A1
-NosT cassette and transgene expression. Five selected lines were further characterized, revealing the ability to withstand
heavy metal toxicity. They survived 0.1 mM CuCl2, a concentration which strongly affected the nontransgenic plants. Moreover, root development was only slightly affected
by the ectopic expression of the transgene. Reactive oxygen species were accumulated to a lower extent in leaf tissues of
multi-auto-transformation (MAT)-PsMTA1 plants exposed to copper and zinc, compared to control plants. Tolerance to photo-oxidative stress induced by paraquat was
another distinctive feature of the MAT-PsMTA1 lines. Finally, low levels of DNA damage were detected by quantifying the amounts of 8-hydroxy-2′-deoxyguanosine in leaf
tissues of the transgenic plants exposed to copper. 相似文献
140.
Cossu F Mastrangelo E Milani M Sorrentino G Lecis D Delia D Manzoni L Seneci P Scolastico C Bolognesi M 《Biochemical and biophysical research communications》2009,378(2):162-167
Inhibitor of apoptosis proteins (IAPs) such as XIAP, cIAP1, and cIAP2 are upregulated in many cancer cells. Several compounds targeting IAPs and inducing cell death in cancer cells have been developed. Some of these are synthesized mimicking the N-terminal tetrapeptide sequence of Smac/DIABLO, the natural endogenous IAPs inhibitor. Starting from such conceptual design, we generated a library of 4-substituted azabicyclo[5.3.0]alkane Smac-mimetics. Here we report the crystal structure of the BIR3 domain from XIAP in complex with Smac037, a compound designed according to structural principles emerging from our previously analyzed XIAP BIR3/Smac-mimetic complexes. In parallel, we present an in silico docking analysis of three Smac-mimetics to the BIR3 domain of cIAP1, providing general considerations for the development of high affinity lead compounds targeting three members of the IAP family. 相似文献