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951.
Bonanomi G Incerti G Barile E Capodilupo M Antignani V Mingo A Lanzotti V Scala F Mazzoleni S 《The New phytologist》2011,191(4):1018-1030
Litter decomposition provides nutrients that sustain ecosystem productivity, but litter may also hamper root proliferation. The objectives of this work were to assess the inhibitory effect of litter decomposition on seedling growth and root proliferation; to study the role of nutrient immobilization and phytotoxicity; and to characterize decomposing litter by (13)C NMR spectroscopy. A litter-bag experiment was carried out for 180 d with 16 litter types. Litter inhibitory effects were assessed by two bioassays: seed germination and root proliferation bioassays. Activated carbon (C) and nutrient solutions were used to evaluate the effects of phytotoxic factors and nutrient immobilization. An inhibitory effect was found for all species in the early phase of decomposition, followed by a decrease over time. The addition of activated C to litter removed this inhibition. No evidence of nutrient immobilization was found in the analysis of nitrogen dynamics. NMR revealed consistent chemical changes during decomposition, with a decrease in O-alkyl and an increase in alkyl and methoxyl C. Significant correlations were found among inhibitory effects, the litter decay rate and indices derived from NMR. The results show that it is possible to predict litter inhibitory effects across a range of litter types on the basis of their chemical composition. 相似文献
952.
Peripheral nerves are complex histological structures that can be affected by a variety of conditions with different degree
of axonal degeneration and demyelination. For the study of peripheral nerve regeneration in pathology and tissue engineering,
it is necessary to evaluate the regeneration, remyelination and extracellular matrix reorganization of the neural tissue.
Currently, different histochemical techniques must be used in parallel, and a correlation among their findings should be further
performed. In this work, we describe a new histochemical method for myelin and collagen fibers based on luxol fast blue and
picrosirius methods, for the evaluation of the morphology, the myelin sheath and the collagen fiber reorganization using a
model of peripheral nerve regeneration. Whole brain, normal sciatic nerve and regenerating peripheral nerve samples were fixed
in 10% neutral buffered formalin and paraffin-embedded, for the performance of the hematoxylin-eosin stain, the Luxol fast
blue method and the new histochemical method for myelin and collagen. The results of this technique revealed that this new
histochemical method allowed us to properly evaluate histological patterns, and simultaneously observe the histochemical reaction
for myelin sheath and collagen fibers in normal tissue, and during the regeneration process. In conclusion, this new method
combines morphological and histochemical properties that allowed us to determine with high accuracy the degree of remyelination
and collagen fibers reorganization. For all these reasons, we hypothesize that this new histochemical method could be useful
in pathology and tissue engineering. 相似文献
953.
Vinci B Duret C Klieber S Gerbal-Chaloin S Sa-Cunha A Laporte S Suc B Maurel P Ahluwalia A Daujat-Chavanieu M 《Biotechnology journal》2011,6(5):554-564
Down-regulation of detoxification genes, notably cytochrome P450 (CYPs), in primary hepatocyte cultures is a long-standing and major concern. We evaluated the influence of medium flow in this model. Hepatocytes isolated from 12 different liver donors were cultured either in a multichamber modular bioreactor (MCmB, flow rate 250-500 μL/min) or under standard/static conditions, and the expression of 32 genes, enzyme activities and biological parameters were measured 7-21 days later. mRNA expression of genes involved in xenobiotic/drug metabolism and transport, including CYP1A1, 1A2, 2B6, 2C9, 3A4 (and activities for some of them), UDP-glucuronosyltransferase (UGT) 1A1, UGT2B4, UGT2B7, glutathione S-transferase (GSTα), and multidrug resistance protein 1 (MDR1) and MRP2, were specifically up-regulated by medium flow as compared with static controls in all cultures tested. In 2-week-old cultures, expression of detoxification genes reached levels close to or higher than those measured in freshly isolated hepatocytes. In contrast, CYP2D6 and most of other tested genes were not affected by medium flow. We conclude that medium flow specifically interferes with, and up-regulates, the activity of xenosensors and/or the expression of detoxification genes in primary human hepatocytes. Down-regulation of detoxification genes in conventional (static) cultures is therefore partly a consequence of the absence of medium circulation. 相似文献
954.
955.
Grozio A Millo E Guida L Vigliarolo T Bellotti M Salis A Fresia C Sturla L Magnone M Galatini A Damonte G De Flora A Bruzzone S Bagnasco L Zocchi E 《Biochemical and biophysical research communications》2011,(4):696-701
The phytohormone abscisic acid (ABA), in addition to regulating several important physiological functions in plants, is also produced and released by human granulocytes and monocytes where it stimulates cell activities involved in the innate immune response.Here we describe the properties of an ABA synthetic analog that competes with the hormone for binding to human granulocyte membranes and to purified recombinant LANCL2 (the human ABA receptor) and inhibits several ABA-triggered inflammatory functions of granulocytes and monocytes in vitro: chemotaxis, phagocytosis, reactive oxygen species production and release of prostaglandin E2 (PGE2) by human granulocytes, release of PGE2 and of monocyte chemoattractant protein-1 by human monocytes. This observation provides a proof of principle that ABA antagonists may represent a new class of anti-inflammatory agents. 相似文献
956.
Pieretti G Puopolo G Carillo S Zoina A Lanzetta R Parrilli M Evidente A Corsaro MM 《Carbohydrate research》2011,(17):2705-2709
Pseudomonas chlororaphis subsp. aureofaciens strain M71 was isolated from the root of a tomato plant and it was able to control in vivo Fusarium oxysporum f. sp. radicis-lycopersici responsible for the tomato crown and root rot. Recently, strain M71 was evaluated even for its efficacy in controlling Seiridium cardinale, the causal agent of bark canker of common cypress (Cupressus sempervirens L.). Strain M71 ability to persist on the tomato rhizosphere and on the aerial part of cypress plants could be related to the nature of the lipopolysaccharides (LPS) present on the outer membrane and in particular to the O-specific polysaccharide.A neutral O-specific polysaccharide was obtained by mild acid hydrolysis of the lipopolysaccharide from P. chlororaphis subsp. aureofaciens strain M71. By means of compositional analyses and NMR spectroscopy, the chemical repeating unit of the polymer was identified as the following linear trisaccharide. 相似文献
957.
We report the conformational analysis by 1H‐nmr and computer simulations of five potent sweet molecules, N‐(3,3‐dimethylbutyl)‐L ‐aspartyl‐S‐(α‐methyl)phenylalanine methylester (1; 5000 times more potent than sucrose), L ‐aspartyl‐D ‐valine (S)‐α‐methoxycarbonylmethylbenzylamide (2; 1400 times more potent than sucrose), L ‐aspartyl‐D ‐valine α‐phenylcyclopentylamide (3; 1200 times more potent than sucrose), L ‐aspartyl‐D ‐α‐aminobutyric acid (S)‐α‐cyclohexylpropylamide (4; 2300 times more potent than sucrose), and L ‐aspartyl‐D ‐valine (R)‐α‐methylthiomethylbenzylamide (5; 3000 times more potent than sucrose). The “L‐shaped” structure, which we believe to be responsible for sweet taste, is accessible to all five sweet compounds in solution. This structure is characterized by a zwitterionic ring formed by the A‐H and B containing moieties located in the +y axis and by the hydrophobic group X pointing into the +x axis. Other accessible conformations of these flexible molecules are extended conformations with the A‐H and B containing moieties in the +y axis and the hydrophobic group X pointing in the −y axis and reversed L‐shaped structures with the hydrophobic group X projecting along the −x axis. The remarkable potency of the N‐alkylated compound 1 supports our recent hypothesis that a second hydrophobic binding domain in addition to interactions arising from the L‐shaped structure leads to an enhancement of sweetness potency. © 1999 John Wiley & Sons, Inc. Biopoly 49: 525–539, 1999 相似文献
958.
YU‐SONG GUO ZHONG‐DUO WANG CHU‐WU LIU LI LIU YUN LIU 《Molecular ecology resources》2007,7(6):1219-1221
A total of 37 microsatellite loci from the Russell's snapper, Lutjanus russellii, were successfully isolated and characterized. Thirty‐four loci were polymorphic in L. russellii samples. Twenty of the 37 markers did not differ significantly from Hardy–Weinberg expected genotype proportions. Significant linkage disequilibrium was detected in one pairwise comparison. The numbers of alleles and observed heterozygosities in polymorphic loci ranged from two to 16 and from 0.41 to 0.95, respectively. These markers will be useful for studying the population genetic structure of this species. 相似文献
959.
The rules that govern scientific naming in botany (including phycology and mycology) are revised at Nomenclature Section meetings at successive International Botanical Congresses. The most recent edition of the International Code of Botanical Nomenclature (Vienna Code) embodies the decisions of the XVII International Botanical Congress held in Vienna in 2005 and supersedes the Saint Louis Code. This paper presents an account of the main differences between the two Codes, including those related with starting points, effective publication, valid publication, fossil plants, pleomorphic fungi, orthography, and the Appendices. 相似文献
960.
Spatial and temporal dynamics of macroinvertebrate communities have usually been linked to several environmental and anthropic
factors. The aim of this study is to elucidate how important are these factors in structuring macroinvertebrate communities
from temperate regions. Regarding the macroinvertebrate number of taxa, the Habitat Template Model, the Dynamic Equilibrium
Hypothesis and the Intermediate Disturbance Hypothesis will be tested in order to know how important the diversity of instream
elements and the hydrological disturbance frequency are in defining the macroinvertebrate taxonomic richness. Thus, the structure
and composition of macroinvertebrate communities were analysed in nine sites of the Pas River basin, a temperate Atlantic
basin in northern Spain, during winter, spring, summer and autumn 2005, together with water physicochemical and environmental
characteristics. Macroinvertebrate abundance increased downstream and during summer, probably favoured by lower hydraulic
stress and water organic enrichment. As predicts the Habitat Template Model, the macroinvertebrate number of taxa was related
to habitat heterogeneity. However, no clear relationship amongst macroinvertebrate richness and water quality was found. The
macroinvertebrate taxonomic richness did not correspond exactly with the Dynamic Equilibrium Hypothesis and the Intermediate
Disturbance Hypothesis because it was relatively high in the absence of hydrological disturbances (summer). Thus, disturbance
events may play a secondary role in determining the seasonal dynamic of the number of taxa. However, hydrological disturbances
can be considered the most important factors explaining the seasonal pattern of macroinvertebrate abundance. On the other
hand, spatial patterns of macroinvertebrate community structure and composition were mainly determined by resource availability,
hydraulic conditions, habitat heterogeneity and human alterations, whilst hydrological predictability and resource availability
might play a major role in determining seasonal dynamics. 相似文献