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91.
Asim Kadioglu Neslihan Saruhan Aykut Sağlam Rabiye Terzi Tuba Acet 《Plant Growth Regulation》2011,64(1):27-37
Salicylic acid (SA) is one of the important signal molecules modulating plant responses to environmental stress. In this study,
the effects of exogenous SA on leaf rolling, one of drought avoidance mechanisms, and antioxidant system were investigated
in Ctenanthe setosa during long term drought stress. The plants were subjected to 38-day drought period and they were treated with or without
SA (10−6 M) on the 25th, 27th and 29th days of the period. Leaf samples were harvested on the 30th, 34th and 38th days. Some antioxidant
enzyme activities (superoxide dismutase, catalase, ascorbate peroxidase, dehydroascorbate reductase, monodehydroascorbate
reductase, glutathione reductase), reactive oxygen species (hydrogen peroxide and superoxide) and lipid peroxidation were
determined during the drought period. Treatment with SA prevented water loss and delayed leaf rolling in comparison with control
leaves. Exogenous SA induced all antioxidant enzyme activities more than control leaves during the drought. Ascorbate and
glutathione, α-tocopherol, carotenoid and endogenous SA level were induced by the SA treatment. Levels of reactive oxygen
species were higher in SA treated plants than control ones on the 34th day. Their levels on the 38th day, however, fastly
decreased in SA treated plants. SA treatment prevented lipid peroxidation while the peroxidation increased in control plants.
The results showed that exogenous SA can alleviate the damaging effect of long term drought stress by decreasing water loss
and inducing the antioxidant system in the plant having leaf rolling, alternative protection mechanism to drought. 相似文献
92.
Prof. Dr. Veysel Çomaklı Dr. Rüya Sağlamtaş Prof. Dr. Müslüm Kuzu Dr. Yalçın Karagöz Assoc. Prof. Dr. Tuba Aydın Prof. Dr. Ramazan Demirdağ 《化学与生物多样性》2023,20(5):e202201231
In the study, water, ethanol, methanol, dichloromethane, and acetone extracts of Asparagus officinalis L. were obtained by maceration. DPPH⋅, ABTS⋅+, FRAP, and CUPRAC methods determined the antioxidant capacities of all extracts. Moreover, the in vitro effects of extracts on acetylcholinesterase (AChE), butyrylcholinesterase (BChE), carbonic anhydrase (CA)-I, CA-II and α-Glycosidase were investigated. At a 10 μg/ml concentration, the extract with the highest Fe3+ reduction capacity was ethanol (AE), and the extract with the highest Cu2+ reduction capacity was acetone (AA). AE for AChE (IC50=21.19 μg/ml) and α-Glycosidase (IC50: 70.00 μg/ml), methanol (AM) for BChE (IC50=17.33 μg/ml), CA−I and II (IC50=79.65 and 36.09 μg/ml, respectively) showed the most potent inhibition effect. The content analysis of acetone extract was performed with LC/MS-MS, the first three phytochemicals found most were p-Coumaric acid, rutin, and 4-hydroxybenzoic acid (284.29±3.97, 135.39±8.19, and 102.06±5.51 μg analyte/g extract, respectively). 相似文献
93.
Tayyibe Beyza Yücel Büşra Korkmaz Tuğba Cebeci Ülkü Karaman Yeliz Kasko Arici Seda Fandakli Tuba Gül 《化学与生物多样性》2023,20(9):e202300965
In the present study, the volatile composition of Ulva rigida (U. rigida) was elucidated by two different methods. As a result of the identification process of volatile components using the GC/MS-FID instrument, 31 compounds were identified by hydrodistillation (HD) method, and 15 compounds were identified by solid-phase microextraction (SPME) method, elucidating the structure of 99.86 % and 92.65 %, respectively. The most abundant compounds in the essential oil of U. rigida were n-hexadecanoic acid and pentadecanal, while the most abundant compound according to the SPME analysis was heptadecyne, a hydrocarbon compound. In the next step, hexane, dichloromethane, chloroform and methanol solvent extracts of U. rigida were prepared and the antimicrobial activities of the extracts and the essential oil obtained by hydro-distillation as well as the scolicidal activities of the solvent extracts were determined. The results of the antimicrobial activity test of the essential oil showed a high level of activity against Bacillus cereus ATCC 10876 and MRSA. The highest activity was found on the microorganism of Pseudomonas aeruginosa ATCC 9027 in chloroform and methanol extracts of U. rigida. Furthermore, viability detection was performed and the scolicidal effects of the extracts on protoscoleces were assessed. The values of lethal concentration doses (LD50, LD75 and LD90) were calculated using probit analysis. 相似文献
94.
Z. Tuba H. K. Lichtenthaler Zs. Csintalan Z. Nagy K. Szente 《Physiologia plantarum》1996,96(3):383-388
During a slow desiccation in photosynthetically fully active leaves of the poikilochlorophyllous desiccation-tolerant (PDT) monocotyledon Xerophyta scabrida (Pax) Th. Dur. et Schinz (Velloziaceae), thylakoid activity, CO2 assimilation and respiration decline and chlorophylls and carotenoids are successively broken down. The initially slow rate of leaf water loss is related to the large reduction in leaf area which is reflected in the decrease of specific leaf area. Chlorophylls are broken down faster than carotenoids. The ratio of the variable chlorophyll fluorescence, an indicator of photosynthetic activity (Rfd690-values), shows that the functionality of thylakoids and chlorophylls is successively lost during desiccation. The decline in net CO2 assimilation in desiccating leaves is largely caused by stomatal closure. The complete cessation of CO2 assimilation, however, is due to the breakdown of chlorophylls and thylakoids. Respiration continued during desiccation and remained active far below -3.2 MPa leaf water potential. The differences during desiccation of the photosynthetic apparatus between poikilochlorophyllous and homoiochlorophyllous desiccation-tolerant plants are discussed. 相似文献
95.
The inhibitory effects of the cationic triarylmethane (TAM+) dyes, pararosaniline (PR+), malachite green (MG+), and methyl green (MeG+) on human plasma cholinesterase (BChE) were studied at 25 degrees C in 100 mM Mops, pH 8.0, with butyrylthiocholine as substrate. PR+ and MG+ caused linear mixed inhibition of enzyme activity. The respective inhibitory parameters were K(i) = 1.9 +/- 0.23 microM, alpha = 13 +/- 48, beta = 0 and K(i) = 0.28 +/- 0.037 microM, alpha = 23 +/- 7.4, beta = 0. MeG+ acted as a competitive inhibitor with K(i) = 0.12 +/- 0.017 microM (alpha, infinity, beta, not applicable). The K(i) values were within the same range reported for a number of ChE inhibitors including propidium ion, donepezil, and the phenothiazines, suggesting that TAM+s are active site ligands. On the other hand, the alpha values failed to correlate with values previously reported for a number of ChE inhibitors. It appears that mixed inhibition is the combined result of more than one type of binding and S-I interference. The impact of ligands at the choline-specific and peripheral anionic sites (or, possibly, accessory structural domains) on BChE activity needs to be studied in further detail. 相似文献
96.
Enhanced Water Use Efficiency in Dry Loess Grassland Species Grown at Elevated Air CO2 Concentration 总被引:1,自引:0,他引:1
Net CO2 assimilation rate (PN), stomatal conductance (gs), transpiration rate (E), and water use efficiency (WUE) in four perennial C3 species (grasses: Dactylis glomerata, Festuca rupicola, dicots: Filipendula vulgaris, Salvia nemorosa) grown for 231 d in open-top chambers at ambient (CA, 350 µmol mol-1) or elevated (CE, 700 µmol mol-1) CO2 concentrations were compared. When measured at CE, PN was significantly higher in CE plants of all four species than in the CA ones. The increase in PN was less prominent in the two grasses than in the two dicots. The E was significantly higher in the CE-grass F. rupicola and CE-dicot F. vulgaris than in the CA plants. There was no change in E owing to CE in the other grass and dicot. The gs in F. vulgaris and F. rupicola increased, while there was a decrease in D. glomerata and no change in S. nemorosa. WUE increased in all species grown in CE: four- to five-fold in the dicots and less than two-fold in the grasses. The increase in WUE was primarily due to an increase in PN and not to a decrease in E. 相似文献
97.
98.
Decreased melanocortin‐4 receptor function conferred by an infrequent variant at the human melanocortin receptor accessory protein 2 gene 下载免费PDF全文
99.
Tuba H. Erguder Nico Boon Lieven Wittebolle Massimo Marzorati & Willy Verstraete 《FEMS microbiology reviews》2009,33(5):855-869
For more than 100 years it was believed that bacteria were the only group responsible for the oxidation of ammonia. However, recently, a new strain of archaea bearing a putative ammonia monooxygenase subunit A ( amoA ) gene and able to oxidize ammonia was isolated from a marine aquarium tank. Ammonia-oxidizing archaea (AOA) were subsequently discovered in many ecosystems of varied characteristics and even found as the predominant causal organisms in some environments. Here, we summarize the current knowledge on the environmental conditions related to the presence of AOA and discuss the possible site-related properties. Considering these data, we deduct the possible niches of AOA based on pH, sulfide and phosphate levels. It is proposed that the AOA might be important actors within the nitrogen cycle in low-nutrient, low-pH, and sulfide-containing environments. 相似文献
100.