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61.
Cold represents one of the major abiotic factors influencing plant growth and development worldwide. We analysed the long-term responsiveness of an Iranian spring wheat (cv. Kohdasht) to cold from a proteomic point of view, in order to unravel the molecular mechanisms helping a cold-sensitive cultivar to survive exposure to suboptimal temperatures. Plants were grown at 20 or 4°C until entering the reproductive stage and a cross-comparison on the leaf proteomes was performed. Quantitative analyses on protein alterations occurring upon low-temperature exposure showed a reinforcement in ascorbate recycling (dehydroascorbate reductase, ascorbate peroxidase) and protein processing (proteasome subunit, cysteine proteinase), as well as the accumulation of the enzyme devoted to tetrapyrrole resynthesis (glutamate semialdehyde aminomutase). In contrast, among proteins down-regulated after cold stress, we could identify some key Krebs cycle enzymes (isocitrate dehydrogenase, malate dehydrogenase), together with many photosynthesis-related proteins (oxygen-evolving complex proteins, ATP synthase subunits, ferredoxin NADPH oxidoreductase and some Calvin cycle enzymes). Physiological and biochemical parameters (such as shoot apex dissection, chlorophyll, proline and sugar content determination) sustained proteomics findings allowing the present research to contribute to the current knowledge on these long-term responses, which may be crucial to stress adaptation under field conditions. 相似文献
62.
Ohkawa K Hayashi S Kameyama N Yamamoto H Yamaguchi M Kimoto S Kurata S Shinji H 《Macromolecular bioscience》2009,9(1):79-92
A synthetic route is described for collagen-like polypeptides constructed from O-phospho-L-hydroxyproline [Hyp(PO(3)H(2))] residues. Using the synthetic polypeptides and a natural protein, gelatin, fine fibers and their network structures (ESNWs) were prepared via electrospinning. The composite ESNWs can induce the mineralization of calcium phosphate. The phosphoryl groups of the Hyp(PO(3)H(2)) residues affect both the crystalline phase and amount of the calcium phosphate, depending on the chemical structure in the repeating sequence. The composite ESNWs can be developed as a biocompatible replacement of the extracellular matrix of hard tissues, and thus can be applied as dental materials for restoration of dental cavities or as a sealant for pits and fissures. 相似文献
63.
The vibrational spectrum of the vinyl bromide cation in the first excited electronic state A 2A' was obtained by one-photon mass-analyzed threshold ionization (MATI) spectroscopy. The use of an improved vacuum-ultraviolet radiation source based on four-wave sum frequency mixing in Hg resulted in excellent sensitivity for MATI signals. From the MATI spectrum, the ionization energy to the A 2A' state of the cation was determined to be 10.9150+/-0.0006 eV. Nearly complete vibrational assignments for the MATI peaks were possible by utilizing the vibrational frequencies and Franck-Condon factors calculated at the density-functional theory (DFT) and time-dependent DFT/B3LYP levels with the 6-311+G(df,p) basis set. 相似文献
64.
Suzan A. Mina Sohair A. Mohamed Farouk R. Melek Soad M. Abd El-Khalik 《Natural product research》2020,34(9):1292-1296
AbstractIn the present study, evaluation of the antiproliferative activity of Pachypodium lamerei Drake leaves (family Apocyaceae) against human breast cancer cell lines MDA-MB-231 was done for the total methanolic extract, crude alkaloidal mixture and ursolic acid using the MTT colorimetric assay. The methanolic extract showed the strongest antiproliferative activity followed by ursolic acid and crude alkaloidal fraction with an IC50 equal to 6.2, 14.55 and 56.3?µg/ml respectively compared to oleocanthal. It is the first record for the LC/ESI-MS/MS alkaloidal profiling of the leaves of P. lamerei. Seven alkaloids were tentatively identified according to their fragmentation patterns. Four alkaloids were related to the parent indole class and two alkaloids belong to the quinoline class in addition to one steroidal alkaloid with a pregnan nucleus. Phytochemical investigation of the methanolic extract led to the isolation of three triterpenoidal compounds including ursolic acid, 11,12-didehydroursolic acid lactone and ursolic acid lactone. 相似文献
65.
Amirhassan?AmiriEmail authorView authors OrcID profile Mehdi?Baghayeri Mina?Sedighi 《Mikrochimica acta》2018,185(8):393
A magnetic sorbent was fabricated by coating the magnetized graphene oxide with polystyrene (PS) to obtain a sorbent of the type GO-Fe3O4@PS. The chemical composition and morphology of the sorbent were characterized. The sorbent was employed for the enrichment of polycyclic aromatic hydrocarbons (PAHs) from water samples. Various parameters affecting the enrichment were investigated. The PAHs were then quantified by gas chromatography with flame ionization detection. Linear responses were found in the range of 0.03–100 ng mL?1 for naphthalene and 2-methylnaphthalene, and of 0.01–100 ng mL?1 for fluorene and anthracene. The detection limits (at an S/N ratio of 3) range between 3 and 10 pg mL?1. The relative standard deviations (RSDs) for five replicates at three concentration levels (0.05, 5 and 50 ng mL?1) of analytes ranged from 4.9 to 7.4%. The method was applied to the analysis of spiked real water samples. Relative recoveries are between 95.8 and 99.5%, and RSD% are <8.4%. 相似文献
66.
A new method for multi-component synthesis of 1,4-dihydropyridine derivatives (1,4-DHPs) in the presence of meglumine supported on multiwalled carbon nanotubes (MWCNTs@meglumine) as a new heterogeneous, highly efficient and reusable catalyst was investigated. The reaction was performed under ultrasonic irradiation in EtOH at room temperature. A new, highly efficient heterogeneous catalyst, short reaction times, high to excellent yield of products, and safe and clean conditions are the advantages of the presented method. 相似文献
67.
In this study density functional theory (DFT) calculations at B3LYP/6-31G(d), B3LYP/6-31+G(d) and B3LYP/6-311+G(2df,2p) levels for geometry optimization and total energy calculation were applied for investigation of the important energy-minimum conformations and transition-state of 1,2-, 1,3-, and 1,4-dithiepanes. Moreover, ab initio calculations at HF/6-31G(d) level of theory for geometry optimization and MP2/6-311G(d)//HF/ 6-31G(d) level for a single-point total energy calculation were reported for different conformers. The obtained results reveal that, the twist-chair conformer is a global minimum for all of these compounds. Also, two local minimum were found in each case, which are twisted-chair and twisted-boat conformers. The boat and chair geometries are transition states. The minimum energy conformation of 1,2-dithiepane is more stable than the lowest energy forms of 1,3-dithiepane and 1,4-dithiepane. Furthermore, the anomeric effect was investigated for 1,3-dithiepane by the natural bond orbital method. The computational results of this study shows that all conformers of 1,3-dithiepane have a hypercojugation system. Finally, the 13C NMR chemical shifts for the conformers of 1,4-dithiepane were calculated, which have good correlation with their experimental values. 相似文献
68.
Ali Reza Kiasat Mina Daei Seyyed Jafar Saghanezhad 《Research on Chemical Intermediates》2016,42(2):581-594
A facile method was developed for the synthesis of β-azido alcohols and β-nitro alcohols in the presence of a novel nano-Fe3O4-copoly[(styrene/acrylic acid)/grafted ethylene oxide (nano-Fe3O4-PS-Co-[PAA-g-PEG]) as a phase-transfer catalyst in water. The catalyst was characterized with IR, SEM, and TGA. This procedure offers several advantages, including excellent regioselectivity, high yields, short reaction times, a recyclable catalyst, easy separation of the catalyst through an external magnet, and easy workup. 相似文献
69.
Synthesis and Cytotoxic Evaluation of Novel 1,2,3‐Triazole‐4‐Linked (2E,6E)‐2‐Benzylidene‐6‐(4‐nitrobenzylidene)cyclohexanones 下载免费PDF全文
Mohammad Mahdavi Maryam Akhbari Mina Saeedi Maryam Karimi Niloufar Foroughi Elahe Karimpour‐Razkenari Heshmatollah Alinezhad Alireza Foroumadi Abbas Shafiee Tahmineh Akbarzadeh 《Helvetica chimica acta》2016,99(3):175-180
This work describes the synthesis of novel 1,2,3‐triazole‐4‐linked (2E,6E)‐2‐benzylidene‐6‐(4‐nitrobenzylidene)cyclo‐hexanones starting from cyclohexanone. 1‐(Cyclohex‐1‐en‐1‐yl)piperidine, the enamine from cyclohexanone and piperidine, reacted with 4‐nitrobenzaldehyde to obtain 2‐(4‐nitrobenzylidene)cyclohexanone. Condensation of the latter compound with (prop‐2‐yn‐1‐yloxy)benzaldehyde derivatives under acidic conditions gave (4‐nitrobenzylidene)‐[(prop‐2‐yn‐1‐yloxy)‐benzylidene]cyclohexanones. Finally, ‘click reaction’ of these derivatives and various organic azides led to the title compounds. All compounds were examined by MTT assay for cytotoxic activity in one human breast cancer cell line, MDA‐MB‐231. 相似文献
70.
Fatemeh Esmaeili‐Marandi Mina Saeedi Issa Yavari Mohammad Mahdavi Abbas Shafiee 《Helvetica chimica acta》2016,99(1):37-40
A synthesis of isoindolo[2,1‐a]quinazolinedione derivatives, coupled with a 1,2,3‐triazole ring system, via the reaction of isatoic anhydride, HC?CCH2NH2, and 2‐formylbenzoic acid is described, which led to the formation of the isoindolo[2,1‐a]quinazoline‐5,11‐dione scaffold having a C?C bond that participated in a click reaction with various organic azides. 相似文献