Antibacterial activity and chemical composition of the essential oil of Grammosciadium platycarpum Boiss. from Iran

The chemical composition of the essential oils obtained from two samples (GP1 and GP2) of Grammosciadium platycarpum Boiss. was analyzed by GC and GC-MS. The analysis of the oils resulted in the identification of twenty-two constituents. Linalool (79.0%-GP1, 81.8%-GP2) and limonene (10.0%, 5.8%) were found to be the major components, respectively. The in vitro antibacterial activities of these oils and their main compounds against seven Gram-positive and Gram-negative bacteria were investigated. The results exhibited that the total oils and their major components possess strong to moderate activities against all the tested bacteria except for Pseudomonas aeruginosa.     

Design optimization of a prosthesis stem reinforcing shell in total hip arthroplasty

The use of a perforated, titanium funicular shell to support the proximal femoral cortex in total hip arthroplasty was evaluated with the aid of both analytical and numerical techniques. The principal interactions between the femoral cortex, the metal shell, the implant stem and the acrylic bone cement were modeled using beam on elastic foundations theory and two-dimensional elasticity theory. Subsequent formulation of this model as a nonlinear design optimization problem enabled the determination of the dimensions of the implant and reinforcing shell which minimized an objective function based on a simplified material failure criterion. Two cases were examined, each with two cervico-diaphyseal angles: case A: with a rigid contact between a proximal prosthesis collar and the calcar femorale and case B: no collar contact (a collarless prosthesis or post-operative loosening). Case A achieved an optimal solution at a stem diameter 11-23 percent of the cortex inner diameter, a stem length to diameter ratio of 12-40, shell diameter 22-53 percent and thickness 0.2-7.2 percent of the cortex inner diameter and thickness, respectively. Case B achieved an optimal solution at a stem diameter 67-92 percent of the cortex inner diameter, length to diameter ratio of 4-6, and no shell. In case A the collar support makes the type of internal fixation unimportant, while in the more realistic case B, the shell is not recommended.     

Are the distributions of variations of circle of Willis different in different populations? – Results of an anatomical study and review of literature

Background  

Previous studies have proposed correlation between variants of the cerebral arterial circle (also known as circle of Willis) and some cerebrovascular diseases. Differences in the incidence of these diseases in different populations have also been investigated. The study of variations in the anatomy of the cerebral arterial circle may partially explain differences in the incidence of some of the cerebrovascular diseases in different ethnic or racial groups.     

Partial purification and characterization of a mannuronan-specific alginate lyase fromPseudomonas aeruginosa

Production of a thick exopolysaccharide coat (alginate) by mucoid strains ofPseudomonas aeruginosa has been shown to contribute to the pathogenicity and persistence of these bacteria in the lungs of patients with cystic fibrosis. Previous studies have shown that some mucoidP. aeruginosa strains produce an enzyme(s) capable of degrading this alginate coat. In this study, an alginate lyase from mucoidP. aeruginosa strain WcM#2 was isolated and characterized. Lyase production was enhanced by the addition of 0.2–0.3m NaCl to the growth media. The lyase was eluted from an alginate-Sepharose affinity column with 0.5m NaCl, which can serve as a simple one-step purification protocol for obtaining semi-pure functional alginate lyase. Fractionation of the enzyme preparation on a Sephadex G-75 sizing column showed that the enzyme has an apparent molecular weight of 40,000, whereas sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) suggested a molecular weight of approximately 43,000. The affinity-purified enzyme had a pH optimum of 9.0, its activity was enhanced in the presence of 0.3m NaCl, and it showed substrate specificity for polymannuronic acid blocks. These results demonstrate the presence of a mannuronan-specific alginate lyase inP. aeruginosa that differs in several respects from previous reports ofP. aeruginosa alginate lyases.     

Essential oil composition and antimicrobial activity of Diplotaenia damavandica

Antimicrobial activity of the essential oils obtained from leaves, root and the seeds of Diplotaenia damavandica Mozaffarian, Hedge & Lamond, an endemic plant to Iran, was determined against 10 microorganisms using the disk susceptibility test as well as measuring minimum inhibitory concentrations. The results showed that all three oils had antibacterial activity against Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli. The essential oil from the leaves had the highest antimicrobial activity against all test microorganisms including the fungal strains. The essential oils compositions were analyzed and determined by GC and GC-MS. The oils analyses resulted in the identification of 16, 17 and 20 compounds representing 94.2%, 96.4% and 95.1% of the total oils, respectively. The main components of the leaf essential oils were (Z)-beta-ocimene (21.6%), alpha-phellandrene (21.3%) and terpinolene (20%). Dill apiol (30.1%) and gamma-terpinene (16.2%) were the main components of the root and seed essential oils, respectively.     

An overlay gel method for identification and isolation of bacterial beta-lactamases

A modification of the iodometric technique using an overlay gel was employed for fast identification and isolation of beta-lactamase types TEM, SHV and AmpC from non-denaturing gels. Osmotic shock preparations of the three beta-lactamases were run on polyacrylamide gels without SDS and ampicillin containing overlay gels were flooded with the iodine solution before being placed on polyacrylamide gel strips. Distinct clear bands appeared in dark blue backgrounds indicating beta-lactamase activity.     

Lattice Plasmon Induced Large Enhancement of Excitonic Emission in Monolayer Metal Dichalcogenides

Plasmonics - Through the integration of a strongly coupled plasmonic nanoantenna array with a monolayer MoSe2, spatial maps of the photoluminescence (PL) are acquired on- and off-resonance to...     

Comparing the Recurrence of Vulvovaginal Candidiasis in Patients Undergoing Prophylactic Treatment with Probiotic and Placebo During the 6 Months

This is a randomized, double-blind, clinical/comparative trial study, involving the recurrence of vaginal candidiasis (VVC) after initial treatment with oral fluconazole in patients undergoing prophylactic management with a probiotic and placebo for 6 months. Fifty-nine VVC patients who were diagnosed based on their history, physical examination, and culture of vaginal discharge were initially treated by a single dose of 150 mg fluconazole. According to the table of random numbers, the sample was divided into two groups. The patients from one group took probiotics, while those from the other group took a placebo, with all of them being continuously monitored for 6 months. The patients complaining of vaginal candidiasis symptoms, such as burning, pruritus, and a vaginal (curd-like) discharge, were examined and the discharge was cultured for candida. The positive cultures were considered to be recurring for the patients in each group. Thirty-one cases from the placebo group and 28 cases from the probiotic group were carefully observed. In total, the 6-month recurrence in the control group was eleven (35.5 %) and in the research group was two (7.2 %). The results from Fisher’s exact test for the value p = 0.01 and OR 0.14 95 % CI (0.028–0.7) showed significant recurrence in the placebo group. The findings demonstrated that taking probiotics withazole antifungal drugs could be highly effective in treating VVC, resulting in a lower recurrence rate as well.     

Development of an optimized random amplified polymorphic DNA protocol for fingerprinting of Klebsiella pneumoniae

Aims:  To develop an optimized random amplified polymorphic DNA (RAPD) protocol for fingerprinting clinical isolates of Klebsiella pneumoniae. Methods and Results:  Employing factorial design of experiments, repeatable amplification patterns were obtained for 54 nosocomial isolates using 1 μmol 1^?1 primer, 4 mmol 1^?1 MgCl₂, 0·4 mmol 1^?1 dNTPs, 2·5 U Taq DNA polymerase and 90 ng DNA template in a total volume of 25 μl. The optimum thermocycling program was: initial denaturation at 94°C for 4 min followed by 50 cycles of 1 min at 94°C, 2 min at 34°C, 2 min at 72°C and a final extension at 72°C for 10 min. The optimized RAPD protocol was highly discriminatory (Simpson’s diversity index, 0·982), and all isolates were typable with repeatable patterns (Pearson’s similarity coefficient ～100%). Seven main clusters were obtained on a similarity level of 70% and 32 distinct clusters on a similarity level of 85%, reflecting the heterogeneity of the isolates. Conclusions:  Systematic optimization of RAPD generated reliable DNA fingerprints for nosocomial isolates of K. pneumoniae. Significance and Impact of the Study:  This is the first report on RAPD optimization based on factorial design of experiments for discrimination of K. pneumoniae.     

Improving Soybean (Glycine max L.) N2 Fixation under Stress

Soybean is a major leguminous plant that has the ability to establish a symbiotic association with the N-fixing bacteria, Bradyrhizobium japonicum. Soils are usually subjected to stress including salinity, drought, acidity, and suboptimal root zone temperature, adversely affecting the symbiotic process between soybean and the bacteria. One of the important processes affecting the performance of soybean under stress is the inhibited exchange of symbiosis-related signaling molecules, specifically genistein, between the host legume and B. japonicum during the initiation of symbiosis. Interestingly, inoculation of B. japonicum with the signal molecule genistein can partially or completely alleviate the stress. Understanding the techniques and the precise molecular pathways, which may be influenced by the signaling molecules during the stress, can be useful to determine parameters that enhance the plant’s ability to cope with stress. For example, the use of proteomic techniques to identify proteins expressed under stress can help characterize those proteins and their involvement in stress. Biotechnological-genetic techniques, either breeding or transformation, are also among the effective methods of improving soybean’s ability to fix N₂ under stress. This can be achieved by identifying the genes, which may be expressed under stress in tolerant bacterial and plant species, and inserting them into the non-tolerant species. This article highlights some important advances in soybean N₂ fixation under different stress conditions, and reviews some of the techniques used to improve the ability of plants and bacteria to efficiently fix N₂ under stress.