Comparison of the growth pattern and Rosharinic acid production in rosemary (Rosmarinus officinalis) shoots and genetically transformed callus cultures

Abstract

Rosmarinic acid is a natural antioxidant and is found as a secondary metabolite in rosemary (Rosmarinus officinalis). It is of interest in food preservation due to its antioxidant and antimicrobial activities. Previously maintained shoot‐based clonal line of rosemary designated as R‐l (based on RA content, total phenolics content, tolerance to Pseudomonas sp and RA stimulation) was used in this study to compare RA biosynthesis in shoot vs callus cultures. Callus cultures were generated from shoot cultures of R‐l line following transformation with Agrobacterium rhizogenes‐containing a natural plasmid that alters plant development. The shoot and transformed callus cultures of R‐l were isolated and maintained separately on hormone free Murashige and Skoog medium (MS/HF). The effect of light and dark conditions on callus growth and RA production was investigated. RA biosynthesis in shoot cultures was also compared due to its relevance to greenhouse production and organ culture. We found that callus maintained in light grows more rapidly when compared to shoot grown in light and callus grown in dark. The ratio of biomass accumulated by callus (Light): callus (Dark): Shoot was 4:1:1 based on fresh weight and 4:1:2 based on dry weight. The ratio of peak RA levels (expressed mg/g DW) was 1:1:10. RA production in callus was small compared to shoot and light had no effect on peak RA level in the callus system, but it effected the growth rate significantly.     

Effect of Selfish Node Behavior on Efficient Topology Design

The problem of topology control is to assign per-node transmission power such that the resulting topology is energy-efficient and satisfies certain global properties such as connectivity. The conventional approach to achieve these objectives is based on the fundamental assumption that nodes are socially responsible. We examine the following question: if nodes behave in a selfish manner, how does it impact the overall connectivity and energy consumption in the resulting topologies? We pose the above problem as a non-cooperative game and use game-theoretic analysis to address it. We study Nash equilibrium properties of the topology control game and evaluate the efficiency of the induced topology when nodes employ a greedy best response algorithm. We show that even when the nodes have complete information about the network, the steady state topologies are suboptimal. We propose a modified algorithm based on a better response dynamic and show that this algorithm is guaranteed to converge to energy-efficient and connected topologies. Moreover, the node transmit power levels are more evenly distributed and the network performance is comparable to that obtained from centralized algorithms.     

A study of the cell wall mechanical properties in unhyperhydrated shoots of oregano (origanum vulgare) inoculated with pseudomonas sp. by load deformation analysis

Abstract

Elite oregano clonal lines are being targeted by our laboratory for food preservative and nutraceutical applications. Oregano (Origanum vulgare) shoot clones inoculated with Pseudomonas sp. resulted in increased phenolics, reduced hyperhydricity, better tolerance to environmental stress and better adaptability when compared to uninoculated control. In order to confirm the qualitative and biochemical observations related to potential lignification and cellulose build up, we have conducted mechanical load deformation analysis using a TEXTURE ANALYZER (extensometer) instrument after killing the shoots in boiling methanol and thereby removing the internal turgor pressure, instead of directly quantifying the lignin content by chemical methods. Protocol in this study was different in that we have used peak force upon rupture, breaking strain, deformability modulus and toughness parameters as the key criteria for demonstrating whether Pseudomonas ‐ induced unhyperhydrated shoots were stronger than the control (hyperhydrated) shoots. The differences in the bulk mechanical properties in hyperhydrated and unhyperhydrated shoots was very small except for deformability modulus which was somewhat higher to form a weakly positive explanation for the potential of higher lignification in the inoculated shoots. Though our decision on whether the inoculated shoots were stronger than the control shoots was inconclusive, our protocol is”; very useful to other laboratories involved in similar studies. This will be particularly useful if the samples do not have very closely competitive properties and therefore the distinguishing features of the protocol and the statistical accuracy in measurements will be clearly evident.