Browse

71 - 80 of 10,594 items :

  • Life Sciences, other x
Clear All

Abstract

Yarrow essential oil is used in complementary and alternative therapy for several diseases. Biological effects of essential oils span various cells and microorganisms. The aim of this study was to investigate the effects of different concentrations of the essential oil obtained from the yarrow plant (Achillea millefolium) on HeLa (CCL-2) cells. The components of the essential oil were studied by means of GC-MS analysis. Out of 10 determined compounds in the essential oil; 1,8-Cineole, Camphor, Beta-eudesmol and Camphene were found to be higher than others; and their biological effects were depicted with Ingeniuty Pathway Analysis (IPA) analysis. Moreover, cell cycle and proliferation tests were conducted on HeLa cells where yarrow plant’s essential oil was used. When extracted yarrow oil applied on HeLA Cells, apoptotic effects had been determined, furthermore proliferation of these cells decreased. In addition, activation of cell cycle control points was observed . Essential oil components could arrest the development of HeLa cells due to induction of cellular damage control mechanisms. In conclusion, we propose that the essential oil had a more repressive effect on HeLa cells, decreases their proliferation and prevented the increase in the number of cells.

Abstract

The potential use of asparaginases has gained tremendous significance in the treatment of acute lymphoblastic leukemia (ALL). Earlier studies suggest L-asparaginases (L-ASP) extracted from Escherichia coli and Erwinia aroideae regulates L-asparagine (L-Asn) from the circulating blood. Prolonged exposure to these enzymes may lead to hypersensitivity reactions. So, it is important to find novel asparaginases with anti-cancer properties. The three-dimensional structure of L-ASP I from Vibrio campbellii was determined by homology modeling using EasyModeller v.4.0. The structure was validated with quality indexing tools and was deposited in Protein Model DataBase. Molecular docking was performed between L-ASP I and ligand substrate L-Asn to study enzyme-substrate interactions. Qualitative and quantitative analysis of L-ASP I enzyme was found to be reliable and stable with a significant protein quality factor (LG score: 7.129). The enzyme is a dimer, belongs to α/β class of proteins. The active sites comprises of N-glycosylation site and a catalytic triad (T14-S117-D92). The binding energy of the docked complex was calculated to be -7.45 kcal/mol. The amino acid T14 identified as a primary nucleophile essential for catalytic reaction. The enzyme L-ASP I of V. campbellii provides a detailed view of structure and functional aspects with ligand substrate L-Asn. This in silico investigation has explicitly demonstrated for the first time that cytosolic L-ASP Type I of V. campbellii to have a catalytic triad which was attributed only to periplasmic L-ASP Type II. Thus, L-ASP I can serve as anti-leukemic agent in the treatment, management and control of ALL.

Abstract

C-terminal amidation is a common feature of wild type membrane disrupting antimicrobial peptides (AMPs). Empirical evidence suggests that this modification increases antimicrobial efficacy. However, the actual role of C-terminal amidation in the molecular mechanism of action of AMPs is not fully understood. Amidation alters two key properties simultaneously: the net charge and helicity of the peptide, both of which are implicated in the mechanism of action. However, the differences between the physicochemical properties of the carboxyl and amide moieties have been disregarded in former studies. In this study we assessed whether the difference in activity is only caused by changes in the helicity and overall charge of a peptide, i.e. whether the chemistry of the terminus is otherwise irrelevant. To do so, the membrane disrupting activity of a modified aurein 1.2 peptide was studied in which a secondary amide was formed with a terminal methyl group, instead of the primary amide as in the wild type peptide. Results of quartz crystal microbalance, dye leakage and circular dichroism experiments show that the activity of the modified peptide is substantially reduced compared to the wild type peptide, in particular that the modified peptide exhibited a much-reduced ability to bind to the membrane. Thus, the primary amide at the C-terminus is required to bind to the membrane, and a secondary amide cannot serve the same purpose. We hypothesize that this difference is related to the hydration state of the terminus. The lack of membrane binding ability of the modified peptide identifies the primary amide moiety at the C terminus as a specific membrane binding motif.

Summary

Mating disruption (MD) has been a successful approach for pest control of several lepidoptera. Field trials to evaluate the efficacy of communication disruption of low pheromone load formulation on Thaumetopoea pityocampa were carried out in 2010 and 2011 in an urban park. The efficacy of MD was assessed by comparing male T. pityocampa catches in pheromone traps, between MD and Control areas. In the 1st year of the application the percentage of male inhibition ranged from 85 to 100% during the 1st month of the flight period and 95-100% during the whole flight period in the 2nd year. The pheromone remained in the polymeric matrix was almost 30% after 7 weeks under laboratory aging conditions. Combining the pheromone release results with the male disorientation results we can assume that after 7 weeks the remaining pheromone concentration was still sufficient to achieve MD. This study indicates that air permeation with the major sex pheromone component (Z)-13-hexadecen-11-ynyl acetate, at a rate of 20 g/ha for one application per season, can affect the orientation of T. pityocampa males. Since mating disruption is an environmentally safe method for pest control, it could be a valuable tool to control T. pityocampa in urban areas and parks.

Abstract

This paper presents a study conducted at major rotaries for quantifying the traffic noise levels by considering the vehicle volume and their respective honking as governing parameters for heterogeneous traffic. Traffic volume and traffic noise data was collected using a digital video camera and a class 1 sound level meter, respectively. The traffic noise data was analysed using noise tools for identifying the noise level variation. The data collected was subjected to statistical analysis for light, medium and heavy vehicles, and their contribution towards noise levels is proven to be effective with the forthright fact that, heavy vehicles and their corresponding honking were majorly affecting the equivalent noise level compared to other vehicular proportion. An equivalent noise level [LAeq (dB)] rise of 2 to 6 dB (A) is solely caused by heavy vehicles, which is an important observation to be considered for traffic noise analysis at the rotaries. Based on the obtained results from one of the rotaries, noise prediction model is developed for estimating the LAeq (dB), which is able to predict the noise levels with good precision when validated with the data collected at second rotary intersection for different vehicle volumes.

Summary

The interactive relationship between the root–knot nematode Meloidogyne incognita and the root-rot fungus Macrophomina phaseolina in a root–rot disease complex of chickpea (Cicer arietinum var. avrodhi) was studied in a net house. The present study was carried out in such a manner so that the pathogenic potential of M. incognita and M. phaseolina individually, simultaneously and sequentially could be monitored. The pathogens singly as well as in combination led to significant reduction in growth, yield, nutrient and biochemical parameters. Gaseous exchange parameters like photosynthetic rate, transpiration rate and stomatal conductance were also reduced following infection of plants by the pathogens. However, maximum reduction was noticed in simultaneous inoculation with both pathogens. Sequential inoculation, where M. incognita preceded M. phaseolina by 15 days, was more damaging to the crop in comparison to that where M. phaseolina preceded M. incognita inoculation by 15 days. Infection by M. phaseolina caused a considerable reduction in the number of galls, egg–masses and nematode multiplication, with the highest reduction observed in plants simultaneously inoculated with the pathogens. Those plants also showed the highest disease severity in terms of percent root–rot. Thus, a manifold action plan to reduce the impact of the root-rot disease complex on chickpea crops has to be formulated.

Abstract

Microalgae have been mentioned as a promising feedstock for biodiesel production. In this study, microalgae Chlorella vulgaris (MCV) was cultivated in a bioreactor with wastewater. After biodiesel production from MCV oil via transesterification reaction, chemical and physical properties of MCV methyl ester were evaluated with regular diesel and ASTM standard. Besides, engine performance and exhaust emissions of CI engine fuelled with the blends of diesel-biodiesel were measured. The GC-MS analysis showed that oleic and linoleic acids were the main fatty acid compounds in the MCV methyl ester. Engine test results revealed that the use of biodiesel had led to a major decrease in CO and HC emissions and a modest reduction in CO2 emissions, whereas there was a minor increase in NOx emissions. Furthermore, there was a slight decrease in the engine power and torque while a modest increase in brake specific fuel consumption which are acceptable due to exhaust emissions reduction. The experimental results illustrate considerable capabilities of applied MVC biodiesel as an alternative fuel in diesel engines to diminish the emissions.

Abstract

Renewable producers can offer selling bids with very low marginal cost since they are not obliged to include on any cost related to the use of energy from the wind or sun. Accordingly, when the Market Operator integrates a renewable bid in the merit-order generation curve, all the generators based on conventional technologies, with higher marginal cost due to the cost of fuels, are displaced to the right. The right-shifting of the merit-order generation curve leads to a lower clearing price, a small increment of the traded energy (almost inelastic demand curve), and a reduction of the total cost of the energy traded in the wholesale market. This is the key mechanism of the well-known merit-order effect of renewables. Load-shifting (demand-side management) plans are expected to yield a reduction of the cost of the traded energy for the customers, since the cost-saving due to the energy eschewed at peak hours would be greater than the extra cost due to the increased demand at off-peak hours. This work will show that the main effects of load-shifting on the market are qualitatively similar to that of renewables, which exemplify the existence a “merit-order effect of load-shifting”. To analyse the characteristics of the merit-order effect of load-shifting, a simplified model has been developed, based on the displacement of the generation and demand curves. A set of scenarios has been generated in order to quantify the main effects on the Spanish/Iberian market for 2015.

Abstract

The objective is to carry out an analysis of remote oil spill detection using multi Remote Piloted Aircraft (RPA). A multi-RPA system provides reliable detection of an oil spill with significant advantages over other existing single RPA methods. The objective is to develop an algorithm of using multi-RPA for the monitoring of oil spills. In this paper centralized and multi-RPA algorithms for oil spill detection are analysed.

Summary

The present study is part of a survey for the identification of plant-parasitic nematodes in the rhizosphere of cultivated and wild olive trees in Crete, Greece. Sixteen species corresponding to 13 genera are added to 20 species belonging to 8 genera, previously reported in the survey. Seven nematode species, Filenchus ditissimus, Filenchus vulgaris, Ogma civellae, Pratylenchoides crenicauda, Psilenchus hilarulus, Tylenchus elegans, and Zygotylenchus guevarai, are recorded for the first time in Greece.