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排序方式: 共有64条查询结果,搜索用时 15 毫秒
1.
Cecilia PC Soh Alastair SR Donald James Feeney Walter TJ Morgan Winifred M Watkins 《Glycoconjugate journal》1989,6(3):319-332
The tetrasaccharides GalNAcß1-4[NeuAc2-3]Galß1-4Glc and GalNAcß1-4[NeuAc2-3]Galß1-4GlcNAc were synthesised by enzymic transfer of GalNAc from UDP-GalNAc to 3-sialyllactose (NeuAc2-3Galß1-4Glc) and 3-sialyl-N-acetyllactosamine (NeuAc2-3Galß1-4GlcNAc). The structures of the products were established by methylation and1H-500 MHz NMR spectroscopy. In Sda serological tests the product formed with 3-sialyl-N-acetyllactosamine was highly active whereas that formed with 3-sialyllactose had only weak activity. 相似文献
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Approaches to breeding for salinity tolerance - a case study on Porteresia coarctata 总被引:2,自引:0,他引:2
R LATHA C SRINIVAS RAO H M SR SUBRAMANIAM P EGANATHAN M S SWAMINATHAN 《The Annals of applied biology》2004,144(2):177-184
Cereals are the world's major source of food for human nutrition. Among these, rice (Oryza sativa) is the most prominent and represents the staple diet for more than two-fifths (2.4 billion) of the world's population, making it the most important food crop of the developing world (Anon., 2000a). Rice production in vast stretches of coastal areas is hampered due to high soil salinity. This is because rice is a glycophyte and it does not grow well under saline conditions. In order to increase rice production in these areas there is a need to develop rice varieties suited to saline environments. Research has shown that Porteresia coarctata, a highly salt tolerant wild relative of rice growing in estuarine soils, is an important material for transferring salt tolerant characteristics to rice. It is quite possible that Porteresia may be used as a parent for evolving better and truly salt resistant varieties. The inadequate results and the difficulties associated with conventional breeding techniques necessitate the use of the tools of crop biotechnology in unravelling some of the characteristics of Porteresia that have been highlighted in this report. In view of the limited resources available for increasing salinity tolerance to the breeders to wild rice germplasm, Porteresia is undoubtedly one of the key source species for elevating salinity tolerance in cultivated rice. 相似文献
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The effect of neurotensin on submaximally-stimulated hepatobiliary and pancreatic secretion was studied in 6 healthy subjects. An intravenous infusion of neurotensin 1.4 ± 0.3 pmol/kg/min, designed to reproduce plasma neurotensin immunoreactivity levels within the physiological range, produced a significant increase in pancreatic bicarbonate output. Plasma concentrations of pancreatic polypeptide rose by 83 ± 16 pmol/l and were associated with a small reduction in trypsin, but no significant change in bilirubin outputs. 相似文献
6.
Michele Carbonelli Chiara La Morgia Giacomo Savini Maria Lucia Cascavilla Enrico Borrelli Filipe Chicani Carolina do V. F. Ramos Solange R. Salomao Vincenzo Parisi Jerry Sebag Francesco Bandello Alfredo A. Sadun Valerio Carelli Piero Barboni 《PloS one》2015,10(6)
Purpose
To investigate the thickness of the retinal layers and to assess the prevalence of macular microcysts (MM) in the inner nuclear layer (INL) of patients with mitochondrial optic neuropathies (MON).Methods
All patients with molecularly confirmed MON, i.e. Leber’s Hereditary Optic Neuropathy (LHON) and Dominant Optic Atrophy (DOA), referred between 2010 and 2012 were enrolled. Eight patients with MM were compared with two control groups: MON patients without MM matched by age, peripapillary retinal nerve fiber layer (RNFL) thickness, and visual acuity, as well as age-matched controls. Retinal segmentation was performed using specific Optical coherence tomography (OCT) software (Carl Zeiss Meditec). Macular segmentation thickness values of the three groups were compared by one-way analysis of variance with Bonferroni post hoc corrections.Results
MM were identified in 5/90 (5.6%) patients with LHON and 3/58 (5.2%) with DOA. The INL was thicker in patients with MON compared to controls regardless of the presence of MM [133.1±7μm vs 122.3±9μm in MM patients (p<0.01) and 128.5±8μm vs. 122.3±9μm in no-MM patients (p<0.05)], however the outer nuclear layer (ONL) was thicker in patients with MM (101.4±1mμ) compared to patients without MM [77.5±8mμ (p<0.001)] and controls [78.4±7mμ (p<0.001)]. ONL thickness did not significantly differ between patients without MM and controls.Conclusion
The prevalence of MM in MON is low (5-6%), but associated with ONL thickening. We speculate that in MON patients with MM, vitreo-retinal traction contributes to the thickening of ONL as well as to the production of cystic spaces. 相似文献7.
Arnaud Lanoue Vincent Burlat Ulrich Schurr Ursula SR R?se 《Plant signaling & behavior》2010,5(8):1037-1038
Rhizosphere is the complex place of numerous interactions between plant roots, microbes and soil fauna. Whereas plant interactions with aboveground organisms are largely described, unravelling plant belowground interactions remains challenging. Plant root chemical communication can lead to positive interactions with nodulating bacteria, mycorriza or biocontrol agents or to negative interactions with pathogens or root herbivores. A recent study1 suggested that root exudates contribute to plant pathogen resistance via secretion of antimicrobial compounds. These findings point to the importance of plant root exudates as belowground signalling molecules, particularly in defense responses. In our report,2 we showed that under Fusarium attack the barley root system launched secretion of phenolic compounds with antimicrobial activity. The secretion of de novo biosynthesized t-cinnamic acid induced within 2 days illustrates the dynamic of plant defense mechanisms at the root level. We discuss the costs and benefits of induced defense responses in the rhizosphere. We suggest that plant defense through root exudation may be cultivar dependent and higher in wild or less domesticated varieties.Key words: root exudates, plant defense, t-cinnamic acid, fusarium, induced defensePlants grow and live in very complex and changing ecosystems. Because plants lack the mobility to escape from attack by pathogens or herbivores, they have developed constitutive and in addition inducible defenses that are triggered by spatiotemporally dynamic signaling mechanisms. These defenses counteract the aggressor directly via toxins or defense plant structures or indirectly by recruitment of antagonists of aggressors. Whereas induced defenses are well described in aboveground interactions, evidence of the occurrence of such mechanisms in belowground interactions remains limited. The biosynthesis of a defensive molecule could be both constitutive and inducible with a low level of a preformed pool (Fig. 1). In addition, upon encounter of an attacking organism, those levels could be induced to rise locally to a high level of active compound that is able to disarm the pathogen.2,3 Only a few examples show that root exudates play a role in induced plant defense. Hairy roots of Ocimum basilicum secrete rosmarinic acid only when challenged by the pathogenic fungus Pythium ultimum.4 Wurst et al.5 reported on the induction of irridoid glycosides in root exudates of Plantago lanceolata in presence of nematodes. In vivo labelling experiments2 with 13CO2 showed the induction of phenolic compounds secreted by barley roots after Fusarium graminearum infection and the de novo biosynthesis of root secreted t-cinnamic acid within 2 days. These results show that the pool of induced t-cinnamic acid originated from both pre-formed and newly formed carbon pools (Fig. 1), highlighting a case of belowground induced defense inside and outside the root system.Open in a separate windowFigure 1Suggested mechanisms for the induction of root defense exudates in barley in response to Fusarium attack. Upon pathogen attack by Fusarium, the initial preformed pool of phenolic compounds is increased by the addition of inducible, de novo biosynthesized t-cinnamic acid. Both, the preformed pool and the de novo biosynthesized pool fuel the exudation of defense compounds from infected roots.The concept of fitness costs is frequently presented to explain the coexistence of both constitutive and induced defense.6 In the case of induced defense, resources are invested in defenses only when the plant is under attack. In the absence of an infection, plants can optimize allocation of their resources to reproduction and growth to compete with neighbours.7 Constitutive defenses are thought to be more beneficial when the probability of attack is high, whereas adjustable, induced defenses are more valuable to fight against an unpredictable pathogen. Non disturbed soil is a heterogeneous matrix where biodiversity is very high and patchy8,9 and organism motility is rather restricted.10 As a consequence of the patchiness, belowground environment is expected to be favourable to selection for induced responses.11 The absence of defense root exudates between two infections may form an unpredictable environment for soil pathogens and reduce the chance for adaptation of root attackers. Plants may also use escape strategies to reduce the effect of belowground pathogens. Henkes et al. (unpublished) showed that Fusarium-infected barley plants reduced carbon allocation towards infected roots within a day and increased allocation carbon to uninfected roots. These results illustrate how reallocation of carbon toward non infected root parts represents a way to limit the negative impact of root infection.We have demonstrated the potential of barley plants to defend themselves against soil pathogen by root exudation.2 Even the barley cultivar ‘Barke’ used in our study, a modern cultivated variety, was able to launch defense machinery via exudation of antimicrobial compounds when infected by F. graminearum. We suggest that plant defense through root exudation might be cultivar dependent and perhaps higher in wild or less domesticated varieties. Taddei et al.12 reported that constitutivelyproduced root exudates from a resistant Gladiolus cultivar inhibit spore germination of Fusarium oxysporum whereas root exudates from a susceptible cultivar do not affect F. oxysporum germination. Root exudates from the resistant cultivar contained higher amounts of aromaticphenolic compounds compared to the susceptible cultivar and these compounds may be responsible for the inhibition of spore germination. Metabolic profiling of wheat cultivars, ‘Roblin’ and ‘Sumai3’, respectively, susceptible and resistant to Fusarium Head Blight, showed that t-cinnamic acid was a discriminating factor responsible for resistance/defense function.13 Therefore it is likely that wild barley varieties hold higher defense capacities compare to cultivated varieties selected for high yield. In the future, plant breeders in organic and low-input farming could use root-system defense ability as new trait in varietal variation. 相似文献
8.
Miriam YH Ueda Paulo G Alvarenga Juliana M Real Eloisa de Sá Moreira Aripuan? Watanabe Ana Maria Passos-Castilho Matheus Vescovi Yana Novis Vanderson Rocha Adriana Seber Jose SR Oliveira Celso A Rodrigues Celso FH Granato 《Memórias do Instituto Oswaldo Cruz》2015,110(4):461-467
Human herpesvirus 6 (HHV-6) may cause severe complications after haematopoietic stem
cell transplantation (HSCT). Monitoring this virus and providing precise, rapid and
early diagnosis of related clinical diseases, constitute essential measures to
improve outcomes. A prospective survey on the incidence and clinical features of
HHV-6 infections after HSCT has not yet been conducted in Brazilian patients and the
impact of this infection on HSCT outcome remains unclear. A rapid test based on
real-time quantitative polymerase chain reaction (qPCR) has been optimised to screen
and quantify clinical samples for HHV-6. The detection step was based on reaction
with TaqMan® hydrolysis probes. A set of previously described primers and
probes have been tested to evaluate efficiency, sensitivity and reproducibility. The
target efficiency range was 91.4% with linearity ranging from 10-106
copies/reaction and a limit of detection of five copies/reaction or 250 copies/mL of
plasma. The qPCR assay developed in the present study was simple, rapid and
sensitive, allowing the detection of a wide range of HHV-6 loads. In conclusion, this
test may be useful as a practical tool to help elucidate the clinical relevance of
HHV-6 infection and reactivation in different scenarios and to determine the need for
surveillance. 相似文献
9.
Attila Brunyanszki Katalin Erdelyi Bartosz Szczesny Gabor Olah Reinaldo Salomao David N Herndon Csaba Szabo 《Molecular medicine (Cambridge, Mass.)》2015,21(1):666-675
The classical role of hemoglobin in the erythrocytes is to carry oxygen from the lungs to the tissues via the circulation. However, hemoglobin also acts as a redox regulator and as a scavenger of the gaseous mediators nitric oxide (NO) and hydrogen sulfide (H2S). Here we show that upregulation of hemoglobin (α, β and δ variants of globin proteins) occurs in human peripheral blood mononuclear cells (PBMCs) in critical illness (patients with severe third-degree burn injury and patients with sepsis). The increase in intracellular hemoglobin concentration is a result of a combination of enhanced protein expression and uptake from the extra-cellular space via a CD163-dependent mechanism. Intracellular hemoglobin preferentially localizes to the mitochondria, where it interacts with complex I and, on the one hand, increases mitochondrial respiratory rate and mitochondrial membrane potential, and on the other hand, protects from H2O2-induced cytotoxicity and mitochondrial DNA damage. Both burn injury and sepsis were associated with increased plasma levels of H2S. Incubation of mononuclear cells with H2S induced hemoglobin mRNA upregulation in PBMCs in vitro. Intracellular hemoglobin upregulation conferred a protective effect against cell dysfunction elicited by H2S. Hemoglobin uptake also was associated with a protection from, and induced the upregulation of, HIF-1α and Nrf2 mRNA. In conclusion, PBMCs in critical illness upregulate their intracellular hemoglobin levels by a combination of active synthesis and uptake from the extracellular medium. We propose that this process serves as a defense mechanism protecting the cell against cytotoxic concentrations of H2S and other gaseous transmitters, oxidants and free radicals produced in critically ill patients. 相似文献
10.
JG Hansen W Gao J Dupuis GT O’Connor W Tang M Kowgier A Sood SA Gharib LJ Palmer M Fornage SR Heckbert BM Psaty SL Booth SUNLIGHT Consortium Patricia A Cassano 《Respiratory research》2015,16(1)