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11.
L. Panizzi Maria Luisa Scarpati Giovanna Oriente 《Cellular and molecular life sciences : CMLS》1955,11(10):383-384
Summary Quinic acid methyl ester, having the 1.4 and 5 hydroxy-groups suitably blocked, was condensed with the carbonilcaffeic acid chloride.Gradual hydrolysis of the condensation compound gave place to chlorogenic acid. 相似文献
12.
Riassunto Osservazioni al M.E. di esemplari diHydra vulgaris attenuata hanno messo in evidenza la presenza di spirochetali nello strato mesogleale. Si fa l'ipotesi che le spirochete siano inquiline di questi polipi d'acqua dolce. Le idre potrebbero forse anche rappresentare un serbatoio di spirochete patogene per altri animali. 相似文献
13.
The buoyancy and strength of sub-continental lithospheric mantle is thought to protect the oldest continental crust (cratons) from destruction by plate tectonic processes. The exact origin of the lithosphere below cratons is controversial, but seems clearly to be a residue remaining after the extraction of large amounts of melt. Models to explain highly melt-depleted but garnet-bearing rock compositions require multi-stage processes with garnet and clinopyroxene possibly of secondary origin. Here we report on orogenic peridotites (fragments of cratonic mantle incorporated into the crust during continent-continent plate collision) from Otr?y, western Norway. We show that the peridotites underwent extensive melting during upwelling from depths of 350 kilometres or more, forming a garnet-bearing cratonic root in a single melting event. These peridotites appear to be the residue after Archaean aluminium depleted komatiite magmatism. 相似文献
14.
Plants also have to follow their diet to be healthy.In addition to light,water,and CO2,they need mineral nutrients which have to be actively uptaken from the so... 相似文献
15.
Guo W Lasky JL Chang CJ Mosessian S Lewis X Xiao Y Yeh JE Chen JY Iruela-Arispe ML Varella-Garcia M Wu H 《Nature》2008,453(7194):529-533
Cancer stem cells, which share many common properties and regulatory machineries with normal stem cells, have recently been proposed to be responsible for tumorigenesis and to contribute to cancer resistance. The main challenges in cancer biology are to identify cancer stem cells and to define the molecular events required for transforming normal cells to cancer stem cells. Here we show that Pten deletion in mouse haematopoietic stem cells leads to a myeloproliferative disorder, followed by acute T-lymphoblastic leukaemia (T-ALL). Self-renewable leukaemia stem cells (LSCs) are enriched in the c-Kit(mid)CD3(+)Lin(-) compartment, where unphosphorylated beta-catenin is significantly increased. Conditional ablation of one allele of the beta-catenin gene substantially decreases the incidence and delays the occurrence of T-ALL caused by Pten loss, indicating that activation of the beta-catenin pathway may contribute to the formation or expansion of the LSC population. Moreover, a recurring chromosomal translocation, T(14;15), results in aberrant overexpression of the c-myc oncogene in c-Kit(mid)CD3(+)Lin(-) LSCs and CD3(+) leukaemic blasts, recapitulating a subset of human T-ALL. No alterations in Notch1 signalling are detected in this model, suggesting that Pten inactivation and c-myc overexpression may substitute functionally for Notch1 abnormalities, leading to T-ALL development. Our study indicates that multiple genetic or molecular alterations contribute cooperatively to LSC transformation. 相似文献
16.
17.
Bouzat C Gumilar F Spitzmaul G Wang HL Rayes D Hansen SB Taylor P Sine SM 《Nature》2004,430(7002):896-900
Neurotransmitter receptors from the Cys-loop superfamily couple the binding of agonist to the opening of an intrinsic ion pore in the final step in rapid synaptic transmission. Although atomic resolution structural data have recently emerged for individual binding and pore domains, how they are linked into a functional unit remains unknown. Here we identify structural requirements for functionally coupling the two domains by combining acetylcholine (ACh)-binding protein, whose structure was determined at atomic resolution, with the pore domain from the serotonin type-3A (5-HT3A) receptor. Only when amino-acid sequences of three loops in ACh-binding protein are changed to their 5-HT3A counterparts does ACh bind with low affinity characteristic of activatable receptors, and trigger opening of the ion pore. Thus functional coupling requires structural compatibility at the interface of the binding and pore domains. Structural modelling reveals a network of interacting loops between binding and pore domains that mediates this allosteric coupling process. 相似文献
18.
Lausch E Janecke A Bros M Trojandt S Alanay Y De Laet C Hübner CA Meinecke P Nishimura G Matsuo M Hirano Y Tenoutasse S Kiss A Rosa RF Unger SL Renella R Bonafé L Spranger J Unger S Zabel B Superti-Furga A 《Nature genetics》2011,43(2):132-137
Vertebral and metaphyseal dysplasia, spasticity with cerebral calcifications, and strong predisposition to autoimmune diseases are the hallmarks of the genetic disorder spondyloenchondrodysplasia. We mapped a locus in five consanguineous families to chromosome 19p13 and identified mutations in ACP5, which encodes tartrate-resistant phosphatase (TRAP), in 14 affected individuals and showed that these mutations abolish enzyme function in the serum and cells of affected individuals. Phosphorylated osteopontin, a protein involved in bone reabsorption and in immune regulation, accumulates in serum, urine and cells cultured from TRAP-deficient individuals. Case-derived dendritic cells exhibit an altered cytokine profile and are more potent than matched control cells in stimulating allogeneic T cell proliferation in mixed lymphocyte reactions. These findings shed new light on the role of osteopontin and its regulation by TRAP in the pathogenesis of common autoimmune disorders. 相似文献
19.
Vincenzo Luca Annarita Stringaro Marisa Colone Alessandro Pini Maria Luisa Mangoni 《Cellular and molecular life sciences : CMLS》2013,70(15):2773-2786
Pseudomonas aeruginosa is an opportunistic bacterial pathogen that forms sessile communities, named biofilms. The non-motile forms are very difficult to eradicate and are often associated with the establishment of persistent infections, especially in patients with cystic fibrosis. The resistance of P. aeruginosa to conventional antibiotics has become a growing health concern worldwide and has prompted the search for new anti-infective agents with new modes of action. Naturally occurring antimicrobial peptides (AMPs) represent promising future template candidates. Here we report on the potent activity and membrane-perturbing effects of the amphibian AMP esculentin(1-21), on both the free-living and sessile forms of P. aeruginosa, as a possible mechanism for biofilm disruption. Furthermore, the findings that esculentin(1-21) is able to prolong survival of animals in models of sepsis and pulmonary infection indicate that this peptide can be a promising template for the generation of new antibiotic formulations to advance care of infections caused by P. aeruginosa. 相似文献
20.
The nervous system is populated by diverse types of neurons, each of which has dendritic trees with strikingly different morphologies. These neuron-specific morphologies determine how dendritic trees integrate thousands of synaptic inputs to generate different firing properties. To ensure proper neuronal function and connectivity, it is necessary that dendrite patterns are precisely controlled and coordinated with synaptic activity. Here, we summarize the molecular and cellular mechanisms that regulate the formation of cell type-specific dendrite patterns during development. We focus on different aspects of vertebrate dendrite patterning that are particularly important in determining the neuronal function; such as the shape, branching, orientation and size of the arbors as well as the development of dendritic spine protrusions that receive excitatory inputs and compartmentalize postsynaptic responses. Additionally, we briefly comment on the implications of aberrant dendritic morphology for nervous system disease. 相似文献