Ultrasonic-aid extraction (UAE) was applied to the extraction of polysaccharides from
Ganoderma lucidum and then the crude polysaccharides were purified by filtration, DEAE cellulose-52 ...chromatography and Sephadex G-100 size-exclusion chromatography in that order. Two main fractions, GP-1 and GP-2, were obtained through the extraction and purification steps. The characterizations, such as molecular weight, monosaccharides composition, ultraviolet spectrum and infrared spectrum of the two fractions were analyzed in this study. Furthermore, the influence of
G. lucidum polysaccharides fractions upon activation of macrophage cell (RAW 264.7) and antitumor activities to the human breast cancer cell (MDA-MB-231) in vitro were evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay. The results indicated that GP-1 and GP-2 can increase the proliferation and pinocytic activity of macrophage significantly and play an inhibited effect on the cancer cell, moreover, the antitumor activity of the GP-1 and GP-2 increased with the participation of the antitumor factors induced from macrophage by polysaccharides fractions.
The synthesis and characterization of Fe, Co and Ni complexes supported by silylene ligands in the past ten years are summarized. Due to the decrease of the electron cloud density on the Si atom ...after coordination, the downfield shift of the
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Si chemical shift is accompanied by the coordination between the free silylene ligand and metal. The strong electron-donating ability of silylene makes the metal center more electron-rich, which is conducive to the oxidative addition reaction in the metal center. In some cases, the coordination ability of silylene is stronger than those of phosphine and carbene ligands. Therefore, silylene transition metal complexes have better catalytic activity. The further challenges in this field are to develop new polydentate silylene ligands, synthesize chelate silylene-phosphine and silylene-carbene ligands, and design new silylene transition metal complexes for more catalytic research.
The synthesis of silylene Fe, Co and Ni complexes in the past ten years is summarized. The further challenges are to design silylene-phosphine and silylene-carbene ligands and synthesize their transition metal complexes for catalytic applications.
Echinacoside (ECH), a natural phenylethanoid glycoside, was first isolated from
DC. (Compositae) sixty years ago. It was found to possess numerous pharmacologically beneficial activities for human ...health, especially the neuroprotective and cardiovascular effects. Although ECH showed promising potential for treatment of Parkinson's and Alzheimer's diseases, some important issues arose. These included the identification of active metabolites as having poor bioavailability in prototype form, the definite molecular signal pathways or targets of ECH with the above effects, and limited reliable clinical trials. Thus, it remains unresolved as to whether scientific research can reasonably make use of this natural compound. A systematic summary and knowledge of future prospects are necessary to facilitate further studies for this natural product. The present review generalizes and analyzes the current knowledge on ECH, including its broad distribution, different preparation technologies, poor pharmacokinetics and kinds of therapeutic uses, and the future perspectives of its potential application.
Approximately 17% of the land worldwide is considered highly vulnerable to non‐native plant invasion, which can dramatically alter nutrient cycles and influence greenhouse gas (GHG) emissions in ...terrestrial and wetland ecosystems. However, a systematic investigation of the impact of non‐native plant invasion on GHG dynamics at a global scale has not yet been conducted, making it impossible to predict the exact biological feedback of non‐native plant invasion to global climate change. Here, we compiled 273 paired observational cases from 94 peer‐reviewed articles to evaluate the effects of plant invasion on GHG emissions and to identify the associated key drivers. Non‐native plant invasion significantly increased methane (CH4) emissions from 129 kg CH4 ha−1 year−1 in natural wetlands to 217 kg CH4 ha−1 year−1 in invaded wetlands. Plant invasion showed a significant tendency to increase CH4 uptakes from 2.95 to 3.64 kg CH4 ha−1 year−1 in terrestrial ecosystems. Invasive plant species also significantly increased nitrous oxide (N2O) emissions in grasslands from an average of 0.76 kg N2O ha−1 year−1 in native sites to 1.35 kg N2O ha−1 year−1 but did not affect N2O emissions in forests or wetlands. Soil organic carbon, mean annual air temperature (MAT), and nitrogenous deposition (N_DEP) were the key factors responsible for the changes in wetland CH4 emissions due to plant invasion. The responses of terrestrial CH4 uptake rates to plant invasion were mainly driven by MAT, soil NH4+, and soil moisture. Soil NO3−, mean annual precipitation, and N_DEP affected terrestrial N2O emissions in response to plant invasion. Our meta‐analysis not only sheds light on the stimulatory effects of plant invasion on GHG emissions from wetland and terrestrial ecosystems but also improves our current understanding of the mechanisms underlying the responses of GHG emissions to plant invasion.
Invasion by non‐native plants is a critical ecological threat, while the situation could be worse because plant invasion can accelerate global climate change by increasing wetland methane and terrestrial nitrous oxide emissions. Based on a summarization of available data, methane emissions in coastal wetlands and nitrous oxide emissions in grasslands were found to increase by 130% and 77.6%, respectively, due to non‐native plants invasion, albeit the 57.0% increase of methane uptakes in invaded grasslands.
Understanding the metal pollution can help governments and estuary management groups manage metal inputs. Here, we comprehensively analyzed the behaviors of seven metals Cd, Zn, Cu, As, Pb, Cr, and ...Hg in water and the responses of these metals to hydrological connectivity in the Pearl River Estuary. The analyses were based on the field measurements of August-2016 in the estuary and January-2016 in the upper river mouth. We also assessed the ecosystem health of these metals. Overall, this estuary had an overall moderate pollution level, with occasional severe perturbations. The mean concentration of individual metal was in the order of Zn > As > Cu > Cr > Pb > Cd > Hg. The eastern estuary was more heavily polluted by metals (notably, Zn, Cd, and Cu) than the western estuary; this condition was attributable to sewage and industrial effluent discharges from the eastern urban cities of Dongguan and Shenzhen. Longitudinally, high levels of Cd and Zn appeared in the upper estuary, while elevated levels of Cu, As, Pb, Cr, and Hg were found in the middle and lower estuaries. The riverine inputs and estuarine mixing significantly influenced the distribution and movement of trace metals in the estuary, and have contributed to phytoplankton productivity (chlorophyll-a > 10 μg/L). River inflow inhibited the vertical diffusion of metals, and tidal currents facilitated surface-to-bottom mixing. Cu and Cd posed ecological risks. We determined the source contributions and transport routes of the metals using principal component analysis combining with multiple linear regression. The results of this study suggest that the source apportionment of metals can help to manage the source input entering into the estuary. Further, identified hydrological connectivity of metals can inform water quality managers in the highly anthropogenically influenced estuary.
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•The metal concentration was in the order of Zn > As > Cu > Cr > Pb > Cd > Hg.•Ecological risks caused by Cu and Cd were high to the ecosystem’s health.•We discussed the effect of hydrological connectivity on metals.•River-tide dynamics influenced surface-to-bottom mixing of the metals.•PCA-MLR was useful to identify the source types and contributions of metals.
Fusarium graminearum Lofgren, Lotus A.; LeBlanc, Nicholas R.; Certano, Amanda K. ...
New phytologist,
February 2018, Letnik:
217, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Mycotoxin-producing Fusarium graminearum and related species cause Fusarium head blight on cultivated grasses, such as wheat and barley. However, these Fusarium species may have had a longer ...evolutionary history with North American grasses than with cultivated crops and may interact with the ancestral hosts in ways which are biochemically distinct.
We assayed 25 species of asymptomatic native grasses for the presence of Fusarium species and confirmed infected grasses as hosts using re-inoculation tests. We examined seed from native grasses for the presence of mycotoxin-producing Fusarium species and evaluated the ability of these fungi to produce mycotoxins in both native grass and wheat hosts using biochemical analysis.
Mycotoxin-producing Fusarium species were shown to be prevalent in phylogenetically diverse native grasses, colonizing multiple tissue types, including seeds, leaves and inflorescence structures. Artificially inoculated grasses accumulated trichothecenes to a much lesser extent than wheat, and naturally infected grasses showed little to no accumulation.
Native North American grasses are commonly inhabited by Fusarium species, but appear to accommodate these toxigenic fungi differently from cultivated crops. This finding highlights how host identity and evolutionary history may influence the outcome of plant–fungal interactions and may inform future efforts in crop improvement.
Four different PSiP-pincer ligands L1–L4 ((2-Ph2PC6H4)2SiHR (R = H (L1) and Ph (L2)) and (2- i Pr2PC6H4)2SiHR′ (R′ = Ph (L3) and H (L4)) were used to investigate the effect of substituents at P ...and/or Si atom of the PSiP pincer ligands on the formation of silyl cobalt(I) complexes by the reactions with CoMe(PMe3)4 via Si–H cleavage. Two penta-coordinated silyl cobalt(I) complexes, (2-Ph2PC6H4)2HSiCo(PMe3)2 (1) and (2-Ph2PC6H4)2PhSiCo(PMe3)2 (2), were obtained from the reactions of L1 and L2 with CoMe(PMe3)4, respectively. Under similar reaction conditions, a tetra-coordinated cobalt(I) complex (2- i Pr2PC6H4)2PhSiCo(PMe3) (3) was isolated from the interaction of L3 with CoMe(PMe3)4. It was found that, only in the case of ligand L4, silyl dinitrogen cobalt(I) complex 4, (2- i Pr2PC6H4)2HSiCo(N2)(PMe3), was formed. Our results indicate that the increasing of electron cloud density at the Co center is beneficial for the formation of a dinitrogen cobalt complex because the large electron density at Co center leads to the enhancement of the π-backbonding from cobalt to the coordinated N2. It was found that silyl dinitrogen cobalt(I) complex 4 is an effective catalyst for catalytic transformation of dinitrogen into silylamine. Among these four silyl cobalt(I) complexes, complex 1 is the best catalyst for hydrosilylation of alkenes with excellent regioselectivity. For aromatic alkenes, catalyst 1 provided Markovnikov products, while for aliphatic alkenes, anti-Markovnikov products could be obtained. Both catalytic reaction mechanisms were proposed and discussed. The molecular structures of complexes 1–4 were confirmed by single-crystal X-ray diffraction.
Acute episodes of amnestic syndrome can be a challenging diagnostic problem. Except for nonvascular etiology, thalamic strokes or infarction involving several temporal lobe structures has been ...reported in earlier cases. The authors report a patient who suddenly developed memory loss without any other focal neurologic deficits. Brain magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) performed 1 day after onset revealed acute infarction involving the bilateral fornix column and the genu of corpus callosum. Because simple fornix infarcts often have no obvious positive neurological signs, most of the related manifestations were provided by family members, are easy to be diagnosed falsely, and missed in clinical areas, we suggest that bilateral fornix infarction should be considered in the diagnosis of an acute onset amnestic syndrome.
The potential protective effects and mechanisms of edaravone have not been well elucidated in vascular dementia (VaD) induced by chronic cerebral hypoperfusion (CCH). The aim of this study was to ...investigate whether edaravone could improve cognitive damage in rats induced by CCH, and whether the effects of edaravone were associated with ERK/Nrf2/HO-1 signaling pathway.
CCH was induced by bilateral common carotid arteries occlusion (BCCAO). Sprague-Dawley (SD) rats were randomly divided into four groups: sham (sham-operated) group, vehicle (BCCAO + normal saline) group, edaravone3.0 group and edaravone6.0 group. The edaravone3.0 and edaravone6.0 group rats were provided 3.0 mg/kg and 6.0 mg/kg of edaravone, respectively, intraperitoneal (i.p.) injection twice daily following the first day after BCCAO. In this experiment, the spatial learning and memory were assessed using the Morris water maze. The malondialdehyde (MDA) contents and superoxide dismutase (SOD) activities in the hippocampus were measured biochemically. And, the levels of total ERK1/2 (t-ERK1/2), Phospho-ERK1/2 (p-ERK1/2), total Nrf2 (t-Nrf2), nuclear Nrf2 (n-Nrf2), and HO-1 were assessed by western blot.
The results showed that the treatment with edaravone significantly improved CCH-induced cognitive damage, and boosted endogenous antioxidants SOD activity and HO-1 level, decreased MDA contents in the hippocampus by activating Nrf2 signaling pathway which was related to ERK1/2. We also found that the neuronal morphology of the hippocampal CA1 area significantly improved and the number of Nrf2 positive cells markedly increased in the edaravone treatment groups.
Our results demonstrated a neuroprotective effect of edaravone on hippocampus against oxidative stress and cognitive deficit induced by CCH. The mechanism may be related to the enhancement of antioxidant defense system by activating ERK/Nrf2/HO-1 signaling pathway.
Abstract Background The majority of patient with post-stroke Vascular Cognitive Impairment (VCI) have Vascular Cognitive Impairment No Dementia (VCIND). The Mini-Mental State Examination (MMSE) has ...been criticized as a poor screening test for VCIND due to insensitivity to visuospatial and executive function impairments. The Montreal Cognitive Assessment (MoCA) was designed to be more sensitive to such deficits and may therefore be a superior screening instrument for VCIND. Methods Stable patients within 14 days of their index stroke without significant physical disability, aphasia, dysarthria, active psychiatric illness or pre-existing dementia were eligible. Cognitive and neurological measures were administered after informed consent. Results 100 patients were recruited. Of the 57 patients with unimpaired MMSE scores, 18 (32%) patients had an impaired MoCA score. By comparison, only 2 out of the 41 (4.9%) patients with unimpaired MoCA scores had impaired MMSE scores. Moreover, MMSE domain subtest scores could not differentiate between groups of differing screening test results, whilst MoCA domain subtest scores (Visuospatial/Executive Function, Attention and Recall) could. Conclusion The MoCA is more sensitive than the MMSE in screening for cognitive impairment after acute stroke. Longitudinal studies are required to establish the prognostic value of MoCA and MMSE evaluation in the acute post-stroke period for cognitive impairment as defined by the standard method of formal neuropsychological evaluation 3–6 months after stroke.
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