Aerobic biodegradation of trichloroethylene using a consortium of five bacterial strains

Degradation with an aerobic consortium was used to evaluate the bioremediation trichloroethylene (TCE) as a model substrate. After one week, 228-1186 mg TCE l(-1) was degraded at rates of 20-50 microg TCE l(-1) h(-1). The introduction of 10 mg toluene l(-1) enhanced the degradation rates for TCE when greater than 600 mg l(-1). Using isolated enzymes, a TCE degradation intermediate(s) appears inhibitory to the oxygenase enzymes thereby diminishing the overall degradation.     

In vitro rapid regeneration of plantlets from nodal explants of Mucuna pruriens– a valuable medicinal plant

A rapid and efficient protocol for the large‐scale propagation of a potential medicinal plant, Mucuna pruriens, through in vitro culture of nodal segment explants obtained from 15‐day‐old aseptic seedlings is described. Of the three different cytokinins, 6‐benzyladenine (BA), kinetin (Kin) and 2‐isopentenyl adenine (2‐iP) evaluated as supplements to Murashige and Skoog (MS) medium, BA at an optimal concentration of 5.0 μM was effective in inducing multiple shoots. Strength of the basal media also influenced the efficiency of shoot regeneration. The frequency of shoot regeneration tended to increase when the salt concentration in the basal media was reduced. Highest number of multiple shoots (23.3) and maximum average length (5.6 cm) were standardised on half‐strength MS medium supplemented with 5.0 μM BA along with 0.5 μM α‐naphthalene acetic acid (NAA) at pH 5.8. Rooting was best induced in shoots excised from proliferated shoot cultures on MS medium augmented with an optimal concentration of 1.0 μM indole‐3‐butyric acid (IBA). The in vitro‐raised plantlets with well‐developed shoots and roots were successfully established in earthen pots containing garden soil and were grown in greenhouse with 90% survival rate. The results of this study provide the first report on in vitro plant regeneration of M. pruriens.     

Effect of Transport at Ambient Temperature on Detection and Isolation of Vibrio cholerae from Environmental Samples

It has long been assumed that prolonged holding of environmental samples at the ambient air temperature prior to bacteriological analysis is detrimental to isolation and detection of Vibrio cholerae, the causative agent of pandemic cholera. The present study was aimed at understanding the effect of transporting environmental samples at the ambient air temperature on isolation and enumeration of V. cholerae. For water and plankton samples held at ambient temperatures ranging from 31°C to 35°C for 20 h, the total counts did not increase significantly but the number of culturable V. cholerae increased significantly compared to samples processed within 1 h of collection, as measured by culture, acridine orange direct count, direct fluorescent-antibody-direct viable count (DFA-DVC), and multiplex PCR analyses. For total coliform counts, total bacterial counts, and DFA-DVC counts, the numbers did not increase significantly, but the culturable plate counts for V. cholerae increased significantly after samples were held at the ambient temperature during transport to the laboratory for analysis. An increase in the recovery of V. cholerae O1 and improved detection of V. cholerae O1 rfb and ctxA also occurred when samples were enriched after they were kept for 20 h at the ambient temperature during transport. Improved detection and isolation of toxigenic V. cholerae from freshwater ecosystems can be achieved by holding samples at the ambient temperature, an observation that has significant implications for tracking this pathogen in diverse aquatic environments.     

Dosimetric evaluation study of IMRT and VMAT techniques for prostate cancer based on different multileaf collimator designs

The hypofractionated radiotherapy modality was established to reduce treatment durations and enhance therapeutic efficiency, as compared to conventional fractionation treatment. However, this modality is challenging because of rigid dosimetric constraints. This study aimed to assess the impact of multi-leaf collimator (MLC) widths (10 mm and 5 mm) on plan quality during the treatment of prostate cancer. Additionally, this study aimed to investigate the impact of the MLC mode of energy on the Agility flattening filter (FF), MLC Agility-free flattening filter (FFF), and MLCi2 for patients receiving hypofractionated radiotherapy. Two radiotherapy techniques; Intensity Modulated Radiotherapy (IMRT) and Volumetric Modulated Arc Radiotherapy (VMAT), were used in this research. In the present study, computed tomography simulations of ten patients (six plans per patient) with localized prostate adenocarcinoma were analyzed. Various dosimetric parameters were assessed, including monitor units, treatment delivery times, conformity, and homogeneity indices. To evaluate the plan quality, dose-volume histograms (DVHs) were estimated for each technique. The results demonstrated that the determined dosimetric parameters of planning target volume (PTV)p (such as D mean, conformity, and homogeneity index) showed greater improvement with MLC Agility FF and MLC Agility FFF than with MLCi2. Additionally, the treatment delivery time was reduced in the MLC Agility FF (by 31%) and MLC Agility FFF (by 10.8%) groups compared to the MLCi2 group. It is concluded that for both the VMAT and IMRT techniques, the smaller width (5 mm) MLCs revealed better planning target volume coverage, improved the dosimetric parameters for PTV, reduced the treatment time, and met the constraints for OARs. It is therefore recommended to use 5 mm MLCs for hypofractionated prostate cancer treatment due to better target coverage and better protection of OARs.

     

Utility of the food colorant erythrosine B as an effective green probe for quantitation of the anticancer sunitinib. Application to pharmaceutical formulations and human plasma

Sunitinib is a tyrosine kinase inhibitor used for the treatment of renal cell carcinoma and gastrointestinal stromal tumors. In this study, two spectroscopic methods, spectrofluorometric and spectrophotometric, were utilized to quantify sunitinib in different matrices. In method I, the native fluorescence of erythrosine B was quenched by forming ion-pair complex with increasing quantities of sunitinib. This approach was utilized for measuring sunitinib in its dosage forms and spiked plasma. After excitation at 528 nm, the quenching of fluorescence is linearly related to the concentration across the range of 0.05–0.5 μg mL⁻¹ at 550 nm in Britton–Robinson buffer (pH 4.0), with a correlation value of 0.9999 and a high level of sensitivity with detection limit down to 10 ng mL⁻¹. Method II relies on spectrophotometric measurements of the produced complex at 550 nm across a range of 0.5–10.0 μg mL⁻¹, with good correlation value of 0.9999. This method has a detection limit down to 0.16 μg mL⁻¹. The proposed methodologies were validated according to International Conference on Harmonization (ICH) guidelines with satisfactory results. The stoichiometry of the reaction was determined through the application of Job's method, while the mechanism of quenching was investigated by employing the Stern–Volmer plot. The designated methods were used to estimate sunitinib in its capsules and in spiked human plasma. Additionally, the statistical analysis of the data revealed no substantial differences when compared to previous reported spectroscopic method. Green assessment tools provide further details about the eco-friendly nature of the methods.     

Determination of omeprazole via fluorescence-quenching methodology; application to content uniformity testing

A new, proven, economical spectrofluorimetric approach has been used to determine the proton pump inhibitor omeprazole (OMP). This innovative technique is based on the ability of OMP to quench the native fluorescence of the mercurochrome dye in an acidic (pH 3.6) solution. Because it was discovered that quenching is proportional to the drug concentration, this dye was used as a sensor for OMP detection. The fluorescence intensity was measured at 518/540 nm, and its linear response ranged from 0.2–10.0 μg/mL with a linear coefficient of 0.9999. The computation yielded a limit of quantification (LOQ) of 0.20 μg/mL and a limit of detection (LOD) of 0.07 μg/mL. Every circumstance and element impacting the reaction product was examined in detail. Pharmacopeial standards carried out the validation. The approved method investigated several commercial preparations and formulations, and the results were favorably compared with those provided by a reference method. According to United States Pharmacopeia (USP) rules, content consistency for two distinct formulations was evaluated.     

MazF-induced Growth Inhibition and Persister Generation in Escherichia coli

Toxin-antitoxin systems are ubiquitous in nature and present on the chromosomes of both bacteria and archaea. MazEF is a type II toxin-antitoxin system present on the chromosome of Escherichia coli and other bacteria. Whether MazEF is involved in programmed cell death or reversible growth inhibition and bacterial persistence is a matter of debate. In the present work the role of MazF in bacterial physiology was studied by using an inactive, active-site mutant of MazF, E24A, to activate WT MazF expression from its own promoter. The ectopic expression of E24A MazF in a strain containing WT mazEF resulted in reversible growth arrest. Normal growth resumed on inhibiting the expression of E24A MazF. MazF-mediated growth arrest resulted in an increase in survival of bacterial cells during antibiotic stress. This was studied by activation of mazEF either by overexpression of an inactive, active-site mutant or pre-exposure to a sublethal dose of antibiotic. The MazF-mediated persistence phenotype was found to be independent of RecA and dependent on the presence of the ClpP and Lon proteases. This study confirms the role of MazEF in reversible growth inhibition and persistence.