The effect of epibrassinolide on senescence in wheat leaves

Brassinosleroids (BRs) are new groups of plant hormones with significant growth-promoting activity. Brassinolide (BL) is the most biologically active BR. BRs are considered as hormones, as they influence varied developmental processes like growth, germination of seeds, rhizogenesis, flowering and senescence. Senescence is regulated by phytohormones. This research shows that epibrassinolide (eBL) accelerates or delays senescence in wheat leaf segments. For this aim, epibrassinolide was applied exogenously into the excised wheat leaf segments. An increase in peroxidase activity and decrease in protease activity;, chlorophyll content (at 10and 0.1 mu M. eBL) were detected. However protein content decreased onlY at 10 mu M. eBL. Finally it was observed that eBR accelerated senescence specially at high concentration

The effect of indole-3-acetic acid and benzyladenine on sequential leaf senescence on Helianthus Annuus L. seedlings

The effect of IAA and BA on the mechanism of senescence which occurs in the cotyledons of Helianthus annuus L. seedlings showing epigenic germination has been investigated. In this study 0, 01 mu M and 10 mu M IAA solutions were sprayed to the leaves and BA solutions with the same concentrations - to the cotyledons of 16 days-old seedlings. We have determined chlorophyll content, protein amount, peroxidase activity and the changes in the membrane permeability in the cotyledons of the treated and control seedlings. Compared to the control cotyledons IAA in the concentrations of 10 mu M and 0,01 mu M caused a breakdown of chlorophyll at the ratio of 64% and 54%, respectively. Soluble protein levels in the IAA at 10,mu M treatment decreased in the ratio of 12%. IAA treatments with 10 mu M and 0, 01,mu M stimulated POD activity with about 11 and 8 times, respectively. On the other hand, it has been observated that 10 mu M and 0,01 mu M BA treatment retarted senescence, whereas 0,01 mu M BA and 0,01 mu M IAA when were applied together enhanced senescence. It has been discussed that IAA which is known as an allosteric activators Of cytokinin oxidase stimulates the cytokinin oxidations so it increases senescence that occurs in the cotyledons. In this research, according to the results it has been thought that the senescence signal may be a substance in the nature of IAA

Growth responses of excised radish cotyledons to meta-topolin

Palavan-Unsal, N., Cag, S. and Cetin, E. 2002. Growth responses of excised radish cotyledons to meta-topolin. Can. J. Plant Sci. 82: 191-194. Meta-topolin (mT) has been established as an active aromatic cytokinin by Strnad et al. (1997). The present investigation assessed the effects of mT on radish cotyledon growth. The effect of mT on cotyledon growth, chlorophyll, N and soluble protein contents were measured. Peroxidase (POD) activity and polyamine (PA) contents were also determined. Treatment at 0.25, 0.5 and 1.0 mM mT concentrations resulted in 44, 50 and 57% increments in cotyledon growth, respectively, compared with control cotyledons. Increase in chlorophyll content per cotyledon was highest at low mT concentrations. Peroxidase activity was highest at 1.0 mM mT. Soluble protein content was reduced by the application of mT

Comparison of the effects of meta-topolin and other cytokinins on chlorophyll and protein contents and peroxidase activity in cucumber cotyledons

Cytokinins play an important role in controlling many of the processes that contribute to plant senescence. The aim of this study was to compare the effect of different cytokinins, especially the new aromatic cytokinin meta-topolin (mT), with kinetin (K), benzyladenine (BA), and zeatin (Z) on chlorophyll formation in etiolated cucumber cotyledons. Protein contents and peroxidase activities were also investigated. Exogenous application of cytokinins was effective in stimulating chlorophyll biosynthesis. mT was shown to be the most effective cytokinin in stimulating chlorophyll biosynthesis at low concentrations compared to the other cytokinins. MT treatments at 0.02-0.0002 mug/ml increased the amount of chlorophyll more than threefold compared with control cotyledons. BA stimulated the total chlorophyll content at 0.1-10 mug/ml concentrations, but inhibited at lower (0.01, 0.001 mug/ml) concentrations. K increased the chlorophyll amount at 1 mug/ml concentration to twice that of control cotyledons. Z stimulated the chlorophyll level at almost all the concentrations applied. The effects of the most effective concentrations of cytokinins used in this research on the chlorophyll level and on the protein content were examined. A doubling of protein content in 0.02 mug/ml-mT-treated cotyledons was observed, whereas Z, BA, and K increased the total protein to a lesser extent. BA was shown to have the greatest effect on peroxidase activity

Effect of salicylic acid on pigment, protein content and peroxidase activity in excised sunflower cotyledons

Enviromental stress gives rise to the activation of adaptation and defence responses in plants. It is known that the role of salicylic acid (SA) is quite important in this mechanism. In this study its effect was investigated on excised cotyledons of sunflower (Helianthus annuus L.) seedlings. The sunflower seedlings were grown in dark conditions for 9 days and then their etiolated cotyledons were harvested. Then, they were transferred into Petri dishes containing 0.001 mu M, 0.1 mu M, 10 mu M, 1000 mu M SA. Cotyledons were incubated for 14 hours in the dark at room temperature, then they were incubated in light period for 3 hours. Chlorophyll, carotenoid content, protein amount and peroxidase (POD) activity in the cotyledons was examined. SA 1000 mu M solution showed the toxic effect in growth considering the results of total chlorophyll, carotenoid content and protein amount. An increasing 2 fold of chlorophyll content in 10 mu M SA and 3.5 fold of carotenoid content in 0.1 mu M SA treated cotyledons comparing to the control were observed. Protein amount increased in all concentrations except 1000 mu M SA. POD activity was also stimulated in all concentration of SA solutions. However, the clear difference in 0.001 mu M SA was not seen. As a result, chlorophyll, carotenoid, protein contents and POD activity increased in exogenic SA application

Investigation of anthocyanin localization in various parts of Impatiens balsamina L.

Impatiens balsamina L. is an annual herbaceous plant of Balsamineaceae family and is cultured as a decorative plant in parks and gat-dens. Since it contains a large amount of minerals, calcium oxalate crystals and secondary metabolites (coumarin derivatives, scopoletin, isofraxidin), it is examined as both dangerous and medicinal plant. The aim of this study is to determine in which parts (node, internode, petiole, leaf,pedicel, petal) of I. balsamina L. the pigment anthocyanin accumulates and to measure its amount in the tissues by spectrophotometer. It was seen that the pigment accumulates more in the upper parts of the nodes on the stem, and that the amount of anthocyanin was significantly less in the internodes than in the nodes. The anthocyanin is, responsible for the red color of flower petals was found in high amount in almost all vacuoles of the papillate epidermal cells

In vitro activities of colistin combined with imipenem, tigecycline or cefoperazone-sulbactam against multidrug-resistant Acinetobacter baumannii blood-stream isolates

Acinetobacter baumannii has emerged as one of the most important nosocomial pathogens and multi-drug resistant (MDR) isolates are of great concern worldwide. The aim of the present study was to investigate the in vitro synergistic activity of colistin in combination with other antibiotics against MDR A. baumannii blood stream isolates. A total of 54 non-duplicate, MDR A. baumannii isolates from blood culture specimens obtained between June 2011 and July 2012 were included in the study. In vitro synergistic activity of colistin in combination with imipenem, tigecycline or cefoperazone-sulbactam against study isolates was investigated by Etest superimposing method and the fractional inhibitory concentration (FIC) index was calculated for each antibiotic combination. The most frequent synergistic effect of colistin was found in combination with tigecycline in only 7 isolates (13.0%). All three antibiotics were found to have synergistic effect with colistin in four isolates (7.4%). Of isolates, 46 (85.2%) showed additive effect of colistin in combination with cefoperazone-sulbactam or tigecycline, 45 (83.3%) with imipenem. We found synergistic activity of colistin with other study antibiotics in only a small number of isolates. Although Etest method is a practical method to investigate the synergistic activity, in case of choosing empirical treatment, colistin in combination with another antibiotic may be preferred. [Dis Mol Med 2016; 4(4.000): 51-54

Comparison of the effects of different sa concentrations on senescence in excised rocket (Eruca sativa L.) cotyledons

Senescence, accepted as the last phase of growth in plants, is characterized by a series of degenerative events that decrease the metabolic activity and eventually cause the death of cells, tissues and organs. In the present studies the effect of salicylic acid, a phenolic substance that recently came to be defined as plant growth regulator, especially increasing immunity of plants against infections, regulating thermogenesis in Arum flowers, inhibiting ethylene biosynthesis and germination, reversing the effects of abscisic acid and blocking the wound-induced response on the senescence of excised cotyledons of cultivated Eruca sativa L., (Rocket) was examined. Cotyledons of ten-day-seedlings of E. sativa were cut apart from the petiole and.-used as experiment materials. The fresh weight of cut cotyledons were measured and they were then incubated in 3 ml of salicylic acid at 10(-3), 10(-1), 10(-7), 10(-9) M concentrations and in distilled water as control. After 4 hours of light exposure in climatie room (25 +/- 2 degrees C), total chlorophyll amount, total protein content, peroxidase activity and protein analysis with SDS-PAGE method were assayed spectrophotometrically with biochemical methods. Furthermore, the effect of salicylic acid on fresh weights of rocket cotyledons was studied

The effect of Zn, Cu and Mn on senescence in excised cotyledons of Eruca sativa L.

The mineral nutrient concentrations in soil are affected by factors such as pH, organic matter, clay and redox potentials. The solubility of such micronutrients as Zn, Cu and Mn is increased by lower pH, or vice versa. The alterations in concentration of these nutrients may affect the growth and development of plants, but also lead to their senescence and programmed cell death related to age and mineral nutrient concentrations. This study aimed to explore the senescence rate due to lack of some essential micronutrients, such as Zn, Cu and Mn, associated with indole acetic acid (IAA). In addition to peroxidase and protease activity, total chlorophyll, nitrogen and protein values were determined. Decreased catabolic reactions and delayed senescence were indicated in excised cotyledons from lack of Zn

Survival in rhino-orbito-cerebral mucormycosis: An international, multicenter ID-IRI study

Background: Mucormycosis is an emerging aggressive mold infection. This study aimed to assess the outcome of hospitalized adults with rhino-orbito-cerebral mucormycosis (ROCM). The secondary objective was to identify prognostic factors in this setting. Methods: This study was an international, retrospective, multicenter study. Patients' data were collected from 29 referral centers in 6 countries. All qualified as proven cases according to the EORTC/MSGERC criteria. Results: We included 74 consecutive adult patients hospitalized with ROCM. Rhino-orbito-cerebral type infection was the most common presentation (n = 43; 58.1%) followed by rhino-orbital type (n = 31; 41.9%). Twenty (27%) had acquired nosocomial bacterial infections. A total of 59 (79.7%) patients (16 in combination) received appropriate antifungal treatment with high-doses of liposomal amphotericin B. Fifty-six patients (75.7%) underwent curative surgery. Thirty-five (47.3%) required intensive care unit admission (27; 36.5% under mechanical ventilation). Hospital survival was 56.8%, being reduced to 7.4% in patients with invasive mechanical ventilation. A multivariate binary backward logistic regression model identified confusion at admission (OR 11.48), overlapping hospital-acquired infection (OR 10.27), use of antifungal treatment before diagnosis (OR 10.20), no surgical debridement (OR 5.92), and the absence of prior sinusitis (OR 6.32) were independently associated with increased risk for death. Conclusion: Today, ROCM still has high mortality rate. Improving source control, rational therpy, and preventing nosocomial infections may improve survival in this severe infection