Zinc oxide (ZnO) and ZnO:Cu nanoparticles (NPs) were synthesized using a rapid, controllable, one‐pot and room‐temperature pulsed UV‐laser assisted method. UV‐laser irradiation was used as an effective energy source in order to gain better control over the NPs size and morphology in aqueous media. Parameters effective in laser assisted synthesis of NPs such as irradiation time and laser shot repetition rate were optimized. Photoluminescence (PL) spectra of ZnO NPs showed a broad emission with two trap state peaks located at 442 and 485 nm related to electronic transition from zinc interstitial level (IZn) to zinc vacancy level (VZn) and electronic transition from conduction band to the oxygen vacancy level (VO), respectively. For ZnO:Cu NPs, trap state emissions disappeared completely and a copper (Cu)‐related emission appeared. PL intensity of Cu‐related emission increased with the increase in concentration of Cu2+, so that for molar ratio of Cu:Zn 2%, optimal value of PL intensity was obtained. The photocatalytic activity of Cu‐doped ZnO revealed 50 and 100% increasement than that of undoped NPs under UV and visible irradiation, respectively. The enhanced photocatalytic activity could be attributed to smaller crystal size, as well as creation of impurity acceptor levels (T2) inside the ZnO energy band gap. 相似文献
Four species belonging to Kickxellales (Kickxellomycotina) isolated from soil of Indonesia are described and illustrated.
Two new species of Coemansia, C. asiatica and C. javaensis, were discovered in South Sulawesi and West Java, and two known species of Linderina, L. pennispora and L. macrospora, were discovered in East Kalimantan and South Sulawesi, respectively. These four species are newly added to the Indonesian
mycobiota. A technique for inducing sporulation of C. javaensis and L. macrospora by adding substances derived from invertebrates such as aphids, nereids, or cladocerans to culture media is described. 相似文献
Melatonin (N-acetyl-5-methoxytryptamine) as a natural biostimulating substance provides a number of benefits in stimulating plant growth in stress situations due to its natural antioxidant capacity. Rhizobia also play crucial roles in supporting plant growth under environmental stress conditions. The overall goal of this research is to study the possible positive effects of melatonin and rhizobacterium in enhancing the growth and salinity tolerance of common bean. To accomplish this objective, we conducted in vitro experiment to select the optimal melatonin concentration and treatment time of seed priming for the best germination. Also, a greenhouse experiment was performed to investigate the effect of melatonin pre-treatment applied before rhizobial inoculation to improve the fitness of common bean under salinity stress. The experiment was conducted using a completely randomized factorial design with six replications and three treatments: priming treatments (melatonin priming (PM100), hydro priming (PH) and dry (PD)), salinity (0, 4, 8, 10 and 16 dS m?1) and Rhizobium strain (inoculated (RS?+) and uninoculated (RS?)). Our results showed that melatonin priming promoted bacterial colony size in Petri-dishes. The interactive effects of melatonin and RS?+?was found to alleviate reactive oxygen species (ROS) burst, and hence protect common bean chlorophylls a, b and carotenoid and photosynthetic activity and decrease malondialdehyde content through activation of antioxidant enzymes (superoxide dismutase, peroxidase, catalase and ascorbate peroxidase), facilitation of soluble protein synthesis, maintenance of Na+ and K+ homeostasis, and finally increase shoot dry weight (33.2, 39.5 and 31.5%) and seed yield (78.6, 91 and 54.2%) compared to the combination of PD and RS- treatments under 0, 4 and 8 dS m?1 salinity levels, respectively. Thus, our findings suggest that seed priming with melatonin, especially 100 µM melatonin is an effective strategy that can be used to enhance salt tolerance in common bean.
Biology Bulletin - To evaluate the accumulation potential of zinc (Zn) and chromium (Cr) by Brassica oleracea L. plant, 15-day-old seedlings were exposed to different concentrations of Zn and Cr... 相似文献
Holothuroids (sea cucumbers) are members of the phylum echinodermata, which produce saponins. Saponins exhibit a wide spectrum of pharmacological and biological activities. In this study, we isolated the crude saponins from the body wall of the dominant Iranian species of sea cucumber, Holothuria leucospilota (H. leucospilota). The purpose of this study was to confirm the presence of saponins in the Persian Gulf H. leucospilota and study the hemolytic and cytotoxic activities of these compounds.
Methods:
The body wall of sea cucumber was dried and powdered and the crude saponins were isolated using various solvents. The crude saponins were further purified by column chromatography using HP-20 resin. The foam test, Thin Layer Chromatography (TLC), hemolytic assay, and Fourier Transform Infrared Spectroscopy (FTIR) confirmed the presence of saponins. Cytotoxicity was analyzed using a 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay on A549 cells, a human lung cancer cell line.
Results:
The foam test, hemolytic assay, and TLC supported the presence of saponin compounds in the 80% ethanol fraction of H. leucospilota. The infrared (IR) spectrum of the extract showed hydroxyl (-OH), alkyl (C-H), ether (C-O) and ester (–C=O) absorption characteristic of teriterpenoid saponins. The C-O-C absorption indicated glycoside linkages to the sapogenins. The crude saponin extracted from sea cucumber was cytotoxic to A549 cells.
Conclusion:
The 80% ethanol fraction of saponin isolated from H. leucospilota exhibited hemolytic activity and offers promise as an anti-cancer candidate.Key Words: Sea cucumber, Holothuria leucospilota, Saponin, Hemolytic assay, Cytotoxicity assay相似文献
This study presents the application of the response surface methodology (design) to develop an optimal preparation condition (independent variables) namely shear rate (600–1000?rpm), mixing time (30–60?min), and sonication time (10–20?min) for polyunsaturated fatty acids (docosahexaenoic acid and eicosapentaenoic acid) nanoliposomes. Fifteen lipid mixtures were generated by the Box–Behnken design and nanoliposomes were prepared by the Mozafari (direct hydration and without using organic solvents) method. Nanoliposomes were characterized with respect to entrapment efficiency (EE) and vesicle size as Y1 and Y2 dependent variables, respectively. The results were then applied to estimate the coefficients of response surface model and to find the optimal preparation conditions with maximum EE and minimum vesicle size. The response surface analysis exhibited that the significant (p?0.05) second-order polynomial regression equations were successfully fitted for all dependent variables with no significant (p?>?0.05) lack of fit for the reduced models. The response optimization of experiments was the shear rate: 795?rpm; mixing time: 60?min; and sonication time: 10?min. The optimal nanoliposome had an average diameter of 81.4?nm and EE of 100%. The experimental results of optimal nanoliposomes characterization confirmed an accurate fitness of the predicted values by reduced response surface models. 相似文献
The lipophilic nature of biological membranes restricts the direct intracellular delivery of potential drugs and molecular probes and makes intracellular transport one of the key problems in gene therapy. Because of their ability to cross cell membranes, single walled carbon nanotubes (SWNTs) are of interest as carriers of biologically active molecules, such as small interfering RNAs (siRNAs). We developed a strategy for chemical functionalization of SWNTs with hexamethylenediamine (HMDA) and poly(diallyldimethylammonium)chloride (PDDA) to obtain a material that was able to bind negatively charged siRNA by electrostatic interactions. PDDA-HMDA-SWNTs exhibited negligible cytotoxic effects on isolated rat heart cells at concentrations up to 10 mg/l. PDDA-HMDA-SWNTs loaded with extracellular signal-regulated kinase (ERK) siRNA were able to cross the cell membrane and to suppress expression of the ERK target proteins in primary cardiomyocytes by about 75%. PDDA-functionalized SWNTs thus present an effective carrier system for applications in siRNA-mediated gene silencing. 相似文献
Camel milk has high levels of antioxidant peptides; therefore has a significant role in nutrition and health. There is a wide range of diseases associated with oxidative stress in the body, thereby preventing the production of free radicals followed the occurrence of such reactions have an important role in human health. Some peptides derived from natural sources as natural antioxidants have a significant role in the inhibition of free radicals. The aim of this study was the identification and purification of camel milk proteins and evaluation of their antioxidant properties. For this purpose, camel milk proteins were hydrolyzed and examined the antioxidant properties of resulting peptides. Ultrafiltration and reverse-phase HPLC techniques were used for fractionation of the hydrolysate. Antioxidant activity of peptides were evaluated using different methods such as 2,2′-diphenyl-1-picrylhydrazyl (DPPH·), 2,2′-azinobis(3-ethylbenzothiazo-line-6-sulfonic acid) diammonium salt (ABTS+), superoxide (O2·?), hydroxyl (OH·?) and polyunsaturated fatty acid peroxidation assays. The real-time PCR was performed to evaluate changes in expression of superoxide dismutase gene (SOD) as an antioxidant enzyme in HepG2 cells treated with different concentrations of peptide. Active peaks were analyzed using tandem mass spectrometry and thus identified two peptides NEDNHPGALGEPV (NV-13) and KVLPVPQQMVPYPRQ (KQ-15) with 1348.38 and 1780.15 dalton molecular weight, respectively. Both peptides showed antioxidant effects but KQ-15 peptide showed stronger effects than other. Molecular analysis showed that KQ-15 peptide was also able to increase the expression of SOD gene. The results show that the NV-13 and KQ-15 peptides have a high antioxidant capacity and they can be used to deal with diseases associated with oxidative stress. 相似文献