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11.
Chrysanthemoides monilifera subsp. monilifera (boneseed), a weed of national significance in Australia, threatens indigenous species and crop production through allelopathy. We aimed to identify phenolic compounds produced by boneseed and to assess their phytotoxicity on native species. Phenolic compounds in water and methanol extracts, and in decomposed litter-mediated soil leachate were identified using HPLC, and phytotoxicity of identified phenolics was assessed (repeatedly) through a standard germination bioassay on native Isotoma axillaris. The impact of boneseed litter on native Xerochrysum bracteatum was evaluated using field soil in a greenhouse. Collectively, we found the highest quantity of phenolic compounds in boneseed litter followed by leaf, root and stem. Quantity varied with extraction media. The rank of phenolics concentration in boneseed was in the order of ferulic acid > phloridzin > catechin > p-coumaric acid and they inhibited germination of I. axillaris with the rank of ferulic acid > catechin > phloridzin > p-coumaric acid. Synergistic effects were more severe compared to individual phenolics. The litter-mediated soil leachate (collected after15 days) exhibited strong phytotoxicity to I. axillaris despite the level of phenolic compounds in the decomposed leachate being decreased significantly compared with their initial level. This suggests the presence of other unidentified allelochemicals that individually or synergistically contributed to the phytotoxicity. Further, the dose response phytotoxic impacts exhibited by the boneseed litter-mediated soil to native X. bracteatum in a more naturalistic greenhouse experiment might ensure the potential allelopathy of other chemical compounds in the boneseed invasion. The reduction of leaf relative water content and chlorophyll level in X. bracteatum suggest possible mechanisms underpinning plant growth inhibition caused by boneseed litter allelopathy. The presence of a substantial quantity of free proline in the target species also suggests that the plant was in a stressed condition due to litter allelopathy. These findings are important for better understanding the invasive potential of boneseed and in devising control strategies. 相似文献
12.
Arshid Hussain Ganie Altaf Ahmad Renu Pandey Ibrahim M. Aref Peerzada Yasir Yousuf Sayeed Ahmad Muhammad Iqbal 《PloS one》2015,10(6)
Background
Maize (Zea mays L.) is one of the most widely cultivated crop plants. Unavoidable economic and environmental problems associated with the excessive use of phosphatic fertilizers demands its better management. The solution lies in improving the phosphorus (P) use efficiency to sustain productivity even at low P levels. Untargeted metabolomic profiling of contrasting genotypes provides a snap shot of whole metabolome which differs under specific conditions. This information provides an understanding of the mechanisms underlying tolerance to P stress and the approach for increasing P-use-efficiency.Methodology/Principal Findings
A comparative metabolite-profiling approach based on gas chromatography-mass spectrometry (GC/MS) was applied to investigate the effect of P starvation and its restoration in low-P sensitive (HM-4) and low-P tolerant (PEHM-2) maize genotypes. A comparison of the metabolite profiles of contrasting genotypes in response to P-deficiency revealed distinct differences among low-P sensitive and tolerant genotypes. Another set of these genotypes were grown under P-restoration condition and sampled at different time intervals (3, 5 and 10 days) to investigate if the changes in metabolite profile under P-deficiency was restored. Significant variations in the metabolite pools of these genotypes were observed under P-deficiency which were genotype specific. Out of 180 distinct analytes, 91 were identified. Phosphorus-starvation resulted in accumulation of di- and trisaccharides and metabolites of ammonium metabolism, specifically in leaves, but decreased the levels of phosphate-containing metabolites and organic acids. A sharp increase in the concentrations of glutamine, asparagine, serine and glycine was observed in both shoots and roots under low-P condition.Conclusion
The new insights generated on the maize metabolome in resposne to P-starvation and restoration would be useful towards improvement of the P-use efficiency in maize. 相似文献13.
Glioblastoma multiforme (GBM) is the most common and most aggressive malignant brain tumor. Despite optimal treatment and evolving standard of care, the median survival of patients diagnosed with GBM is only 12–15 months. In this study, we combined progesterone (PROG) and temozolomide (TMZ), a standard chemotherapeutic agent for human GBM, to test whether PROG enhances the antitumor effects of TMZ and reduces its side effects. Two WHO grade IV human GBM cells lines (U87MG and U118MG) and primary human dermal fibroblasts (HDFs) were repeatedly exposed to PROG and TMZ either alone or in combination for 3 and 6 days. Cell death was measured by MTT reduction assay. PROG and TMZ individually induced tumor cell death in a dose-dependent manner. PROG at high doses produced more cell death than TMZ alone. When combined, PROG enhanced the cell death-inducing effect of TMZ. In HDFs, PROG did not reduce viability even at the same high cytotoxic doses, but TMZ did so in a dose-dependent manner. In combination, PROG reduced TMZ toxicity in HDFs. PROG alone and in combination with TMZ suppressed the EGFR/PI3K/Akt/mTOR signaling pathway and MGMT expression in U87MG cells, thus suppressing cell proliferation. PROG and TMZ individually reduced cell migration in U87MG cells but did so more effectively in combination. PROG enhances the cytotoxic effects of TMZ in GBM cells and reduces its toxic side effects in healthy primary cells. 相似文献
14.
The increasing incidence of hospital-acquired infections caused by drug-resistant pathogens, host toxicity, the poor efficacy of drugs and high treatment costs has drawn attention to the potential of natural products as antifungals in mucocutaneous infections and combinational therapies. Moreover, cellular and subcellular targets for these compounds may provide better options for the development of novel antifungal therapies. Eugenol, methyl eugenol and estragole are phenylpropanoids found in essential oil. They are known to possess pharmacological properties including antimicrobial activity. Induction of oxidative stress characterized by elevated levels of free radicals and an impaired antioxidant defence system is implicated as a possible mechanism of cell death. An insight into the mechanism of action was gained by propidium iodide cell sorting and oxidative stress response to test compounds in Candida albicans. The extent of lipid peroxidation (LPO) of cytoplasmic membranes was estimated to confirm a state of oxidative stress. Activity levels of primary defence enzymes and glutathione were thus further determined. Whereas these compounds cause fungal cell death by disrupting membrane integrity at minimum inhibitory concentrations (MIC), sub-MIC doses of these compounds significantly impair the defence system in C. albicans. The study has implications for understanding microbial cell death caused by essential oil components eliciting oxidative stress in Candida. The formation of membrane lesions by these phenylpropanoids thus appears to be the result of free radical cascade-mediated LPO. 相似文献
15.
R.?A.?NazeerEmail author R.?Deeptha R.?Jaiganesh N.?S.?Sampathkumar Shabeena?Yousuf?Naqash 《International journal of peptide research and therapeutics》2011,17(3):209-216
We have investigated the antioxidant activity of protein hydrolysates prepared from backbones of two commercially important
fishes; seela (Sphyraena barracuda) and ribbon fish (Lepturacanthus savala). Pepsin and trypsin hydrolysates were found more potent to inhibit lipid peroxidation in case of ribbon and seela fish respectively
and were further purified by using fast protein liquid chromatography on anion exchange and gel filtration chromatography.
The active peaks after gel filtration chromatography of seela fish was able to scavenge 2,2-diphenyl-1-picryhydrazyl and hydroxyl
radicals by 61 ± 2.3 and 58.7 ± 2.3% and ribbon fish hydrolysate by 60.0 ± 2.6 and 55.6 ± 1.8% as measured by ESR spectroscopy.
And the active fractions showed presence of both essential and non-essential amino acids with high percentages of arginine
(11.95 and 12.76%) and lysine (13.49 and 13.89%). 相似文献
16.
Evolutionary medicine is a perspective on medical sciences derived through application of theory of evolution to aid in therapeutics.
This study sought to determine the level of knowledge and acceptance of evolutionary theory in medical students along with
their attitude toward teaching evolutionary medicine as a part of their undergraduate course. Factors that are likely to cause
difficulty in teaching evolutionary medicine were also identified. A cross-sectional study was carried out at Army Medical
College, National University of Sciences and Technology, Pakistan in which 299 medical students were selected by nonprobability
convenient sampling technique to participate in the study. Participants’ views were obtained by a structured questionnaire
comprised of three sections: appreciation of evolutionary medicine, acceptance of evolutionary theory, knowledge of evolutionary
theory. Medical students had a low acceptance [mean measure of acceptance of theory of evolution (MATE) = 58.32] and a low
knowledge (mean score of 5.20 out of a total ten marks). Students believed that religious beliefs, lack of resources, and
an existent extensive medical curriculum would cause difficulty in imparting such an education despite its potential to improve
medical research and clinical practice. Only 37.2% agreed that the subject should be taught in medical schools as an individual
subject. 相似文献
17.
Ahmad AS Zia S Sayeed I Ansari MA Ahmad M Salim S Yousuf S Islam F 《Biological trace element research》2005,103(1):59-68
The effect of 0.05, 0.1, and 0.2 mg sodium selenite/kg body weight ip on the activities of neurobehavioral, acetyl cholinesterase,
monoamine oxidase, and the content of dopamine and its metabolites in circadian rhythm centers of male Wistar rats was studied
after 7 d of treatment. The results show an appreciable increase in locomotion, stereo-events, distance traveled, and average
speed at the dose of 0.1 and 0.2 mg sodium selenite/kg. The data have shown hyperactivity of animals with various doses of
sodium selenite, and it was significant and dose-dependent after 3 d of treatment. The activity of acetylcholinesterase (AChE)
was inhibited dose dependently, and it was significant in preoptic area with 0.1 or 0.2 mg sodium selenite/kg. Conversely,
in the posterior hypothalamus its activity was significantly elevated with the dose of 0.2 mg sodium selenite/kg, but its
alteration in brain stem was not significant. Monoamine oxidase (MAO) activity was increased in preoptic area with the dose
of 0.1 mg sodium selenite/kg, but its alteration in posterior hypothalamus and brain stem was not significant. The content
of dopamine (DA), 3,4-dihydroxyphenyl acetic acid (DOPAC), and homovanilic acid (HVA) was elevated dose dependently and it
was significant with the doss of 0.1 and 0.2 mg sodium selenite/kg, but the content of DOPAC and HVA in posterior hypothalamus
was not significant with the dose of 0.1 mg sodium selenite/kg. 相似文献
18.
BackgroundWithaferin A, which is a naturally derived steroidal lactone, has been found to prevent angiogenesis and metastasis in diverse tumor models. It has also been recognized by different groups for prominent anti-carcinogenic roles. However, in spite of these studies on withanolides, their detailed anti-metastatic mechanism of action remained unknown. The current study has poised to address the machinery involved in invasion regulation by stable derivative of Withaferin A, 3-azido Withaferin A (3-azidoWA) in human cervical HeLa and prostate PC-3 cells.Conclusion/SignificanceFor this report, we found that 3-azidoWA suppressed motility and invasion of HeLa and PC-3 cells in MMP-2 dependent manner. Our in vitro result strongly suggests that sub-toxic doses of 3-azidoWA enhanced the secretion of extracellular Par-4 that abolished secretory MMP-2 expression and activity. Depletion of secretory Par-4 restored MMP-2 expression and invasion capability of HeLa and PC-3 cells. Further, our findings implied that 3-azidoWA attenuated internal phospho-ERK and phospho-Akt expression in a dose dependent manner might play a key role in inhibition of mouse angiogenesis by 3-azidoWA. 相似文献
19.
Arumugam Parthasarathy Venkatachalam Gopi Subramanian Umadevi Anoop Simna Mohammed Jainuddin Yousuf Sheik H. Divya Elangovan Vellaichamy 《Molecular and cellular biochemistry》2013,378(1-2):217-228
Cardiac hormone atrial natriuretic peptide (ANP) and its receptor natriuretic peptide receptor-A (NPR-A) system acts as an intrinsic negative regulator of abnormal extracellular matrix (ECM) remodeling in the heart. However, the underlying mechanism by which ANP/NPR-A system opposes the ECM remodeling in the diseased heart is not well understood. Here, we investigated the anti-fibrotic mechanism of ANP/NPR-A in fibrotic agonist Angiotensin- II (ANG II)-treated adult cardiac fibroblast (CF) cells. Normal and NPR-A-suppressed adult CF cells were treated with ANG II (10?7 M) in the presence and absence of ANP (10?8 M) for 24 h. Total collagen concentration, activity and expression of MMP-2 and MMP-9, and nuclear translocation of Nuclear factor-kappaB (NF-κB-p50) were studied. NPR-A-suppressed adult CF cells exhibited a more pronounced increase in collagen production, ROS generation, and NF-κB-p50 nuclear translocation as compared to adult CF cells treated with agonist alone. ANP co-treatment significantly reverses the agonist-induced above changes in normal adult CF cells, while it failed to reverse the agonist-induced collagen synthesis in the NPR-A-suppressed adult CF cells. The cGMP analog (8-bromo-cGMP) treatment significantly attenuated the agonist-induced collagen synthesis both in normal and NPR-A-suppressed adult cells. The results of this study suggest that ANP/NPR-A signaling system antagonizes the agonist-induced collagen synthesis via suppressing the activities of MMP-2, MMP-9, ROS generation, and NF-κB nuclear translocation mechanism. 相似文献
20.