Enhancement of Xanthan Biosynthesis Using Medicinal Herbs - A Novel Approach

This study aimed to evaluate the potential of five medicinal herbs in the enhancement of xanthan gum production when used against indigenously isolated (from molasses, an agricultural waste) phytopathogen Xanthomonas campestris MW741556. Antibiotic susceptibility of five medicinal herbs (Moringa oleifera, Bacopa monnieri, Glycyrrhiza glabra, Withania somnifera, and Arthrospira platensis) against X. campestris culture was first checked. All five herbs exhibited a clear zone of inhibition against X. campestris during the investigation. Thereafter their effect on enhancing the xanthan gum production was studied using molasses enriched medium. The results of this experiment showed that all five herbs were capable of enhancing xanthan gum production significantly. Xanthan gum produced differed in viscosity and dried biomass. Among all, A. platensis and M. oleifera were found to be the most promising for xanthan gum production with higher viscosity. These results were further confirmed by the characterization of xanthan gum produced by five herbs using Fourier Transform Infrared Spectroscopy. Further, a multivariate approach using principal component analysis confirmed the variability among the herbs used. This versatility of these medicinal herbs opens the possibility of their utilization and application in various fields

X-ray micrography and imaging of live Neisseria gonorrhea using laser plasma pulsed X-ray sources

Rapid Identification of infectious agents in clinical specimens is important in determination of appropriate therapy. Current procedures for detection of microbial pathogens require fixation-staining for optical microscopy, incubation for growth on selective media, and complete cell lysis for PCR. High resolution X-ray microscopy of live biological specimen is relatively new and restricted to a few synchrotron X-ray sources. We utilized a bench-top source of single-shot laser (nsec) plasma to generate X-rays similar to synchrotron facilities to image live hydrated cells (in 0.9% phosphate buffered saline). 5 aliquot suspension was placed on a small photoresist and covered with a thin (100nm) SiN window. This sealed specimen was positioned in vacuum close to X-ray source, the emission spectrum tuned for optimal absorption by carbon-rich material to etch an image on the resist. The resist was then scanned by an atomic force microscope to give an image of differential X-ray absorption. By this technique we have captured X-ray images (in 10 nanoseconds) of N.gonorrhea cells in their natural state. N.gonorrhea appear round and distinctly oval shaped, diplococci with a distinct division septum were also observed. This data exhibits potential application of real time X-ray microscopy, with no specimen preparation, in instant identification and study of live pathogenic microbes which need not be present in large numbers in the specimen

Application of X-ray micrography and imaging to study the effect of gentamicin on Pseudomonas aeruginosa

Aminoglycosides disrupt the outer membrane of Pseudomonas aeruginosa to facilitate access to their intracellular target. High-resolution X-ray micrography of live specimens is a relatively new technique. We used laser (nanosecond) plasma to image live cells of P. aeruginosa ATCC 27853. After exposure to 25 mg/L gentamicin for 15 min. we observed perturbation of the cell surface, membrane blebbings (370 nm and 273 nm diameter) away from the cell, formation of distinct channels (241 nm long) resulting from indentation and induction of cell elongation from 3-3.6 μm (control) to 4.6-5.26 μm (gentamicin-treated cells). These data illustrate the potential of high-resolution X-ray micrography for studying effects of drugs on live microbiological specimens

How mobile is tritiated water through unsaturated cement-based materials? New insights from two complementary approaches

International audienceThis work presents two complementary approaches (for low and high desaturation) to study tritiated water (HTO) diffusion through unsaturated cement-based materials. The first approach was based on through-diffusion experiments where suction was controlled by osmosis. In the second approach, diffusion experiments were performed in humidity chambers controlled by under-saturated saline solutions. Results revealed a decrease of effective diffusion coefficient by a factor of 10 from 100% to 23% of saturation degree. Comparison with gaseous H$_2$ suggests that HTO diffuses through unsaturated cement-based materials at rates 4 orders of magnitude lower

On detecting CTS duration attacks using K-means clustering in WLANs

IEEE 802.11 based Wireless LAN (WLAN) standard has been one of the most successful wireless technology standards with total expected sales rising to a staggering $6.1Billion by 2015. The proliferation of 802.11 based WLANs highlights the need to focus on development of new solutions for security as enterprises and campuses increasingly being covered by WLANs. Denial of Service (DoS) is one of the popular attacks that prevents WLAN users from accessing the wireless network resources. Most DoS attacks such as the Clear-to-Send (CTS) duration attack is easy to carry out by an attacker. This work focuses on the use of clustering techniques on wireless traffic datasets for detecting CTS-based DoS attacks on 802.11 WLANs. Performance evaluation shows that, under the cases of naïve CTS duration attacker as well as the sophisticated CTS duration attacker, the k-means clustering technique is able to achieve high detection rates and low false positive rates with relatively small values of k (i.e., number of clusters