Design and Development of an Automated Dual-Mode Microscopic System Using Electrically Tunable Lenses.

Maintaining telecentricity and zooming in microscopic systems with prolonged depths of focus is a difficult challenge because these properties degrade while moving to different axial planes in the extended focal depth. In this paper, we propose the proof of concept for an automated dual-mode microscopic system that combines two electrically tunable lenses (ETLs) with a variable numerical aperture controller placed. It acts as a viable solution to allow both multiplane microscopic zooming and telecentricity with consistent image resolution throughout the objective's extended focal depth. The image plane remains fixed for both the modes of operation, namely telecentricity and multiplane zooming. To validate the performance of the proposed idea, both simulations and experiments are carried out at various ETL curvature ranges. Over the whole zoom distance range, the experimental zoom ratio is determined to range from −2.723X to −34.42X. The experimental and simulation findings are compared and found to be quite similar, with magnification error percentages of 2.26% for zoom mode and 1.27% for telecentric mode. The comprehensive explanation of simulation and experimental results demonstrate the feasibility of the proposed method for both multiplane zoom and telecentric operations on a single platform in microscopic applications.

Genotoxicity evaluation of tannery effluent treated with newly isolated hexavalent chromium reducing Bacillus cereus.

In this study, the efficiency of free and immobilized cells of newly isolated hexavalent chromium [Cr(VI)] reducing Bacillus cereus strain Cr1 (accession no. KJ162160) was studied in the treatment of tannery effluent. The analysis of effluents revealed high chemical oxygen demand (COD-1260 mg/L), biological oxygen demand (BOD5-660 mg/L), total dissolved solids (TDS-14000 mg/L), electrical conductivity (EC-21.5 mS/cm) and total chromium (TC-2.4 mg/L). The effluents also showed genotoxic effects to Allium cepa. Treatment of tannery effluent with isolated B. cereus strain led to considerable reduction of pollutant load. The pollutant load reduction was studied with both immobilized and free cells and immobilized cells were more effective in reducing COD (65%), BOD (80%), TDS (67%), EC (65%) and TC (92%) after 48 h. GC-MS analysis of pre and post-treatment tannery effluent samples revealed reduction of organic load after treatment with free and immobilized cells. An improvement in mitotic index and reduction in chromosomal aberrations was also observed in A. cepa grown with post-treatement effluent samples compared to untreated sample. Results demonstrate that both methods of bacterial treatment (free and immobilized) were efficient in reducing the pollutant load of tannery effluent as well as in reducing genotoxic effects, however, treatment with immobilized cells was more effective.

Rare finding of duodenal lymphangioma in a patient with Helicobacter pylori associated gastritis: A case report.

RATIONALE: Lymphangiomas are lymphatic malformations most commonly found in the head, neck and axilla. Their incidence in gastrointestinal tract, especially duodenum is very rare. They are mostly congenital and are usually seen in children. Owing to their asymptomatic nature, these tumors are often diagnosed incidentally. Surgical resection is the definite treatment. PATIENT CONCERNS: We represent a case of a 30-year-old male with duodenal lymphangioma with presentation of intermittent dyspepsia for 1 year, partially relieved by a proton pump inhibitor. DIAGNOSES: Upon physical examination, there was mild tenderness observed in the epigastrium. The rest of the physical examination was unremarkable. His complete blood count report was unremarkable. Upon a negative stool for Helicobacter pylori antigen test, the patient underwent an esophagogastroduodenoscopy which revealed H pylori gastritis and a duodenal lymphangioma. INTERVENTIONS: Patient was put on triple therapy (clarithromycin, amoxicillin and omeprazole) for 14 days and his symptoms improved. The lymphangioma was not resected owing to small size. OUTCOMES: Patient was followed till 1 year and his symptoms had improved. LESSONS: The case describes a correlation between H pylori gastritis and a duodenal lymphangioma. There is likely to be an association between the two and therefore, further studies are required to find out any relationship that may exist between the 2 conditions.

Simulation and analysis of variable numerical aperture wide-field microscopy for telecentricity with constant resolution.

In this work, we propose simulation and analysis of a novel combination of a variable numerical aperture wide-field microscope objective with an Electrically Tunable Lens (ETL) for axial scanning with a telecentric image space. This work resolves the challenges of the conventional ETL based wide-field microscopic systems viz. variable magnification, field-of-view (FOV), an inconsistent lateral and axial resolution. The proposed combination performs the tuning of the object plane by changing ETL current and effectively modifies the object space numerical aperture using an aperture controller to provide a stationary telecentric image plane. Moreover, with the proposed combination, the lateral resolution of the system is preserved over an axial range of 7.586mm with a magnification error of 2.55 %. The proposed work witnesses the advantages of providing fast axial scanning, extended axial scanning range, autofocusing, invariant magnification, constant FOV, and constant resolution along with a compact optical setup.

Evaluation of bioremediation potentiality of ligninolytic Serratia liquefaciens for detoxification of pulp and paper mill effluent.

Due to high pollution load and colour contributing substances, pulp and paper mill effluents cause serious aquatic and soil pollution. A lignin-degrading bacterial strain capable of decolourising Azure-B dye was identified as lignin peroxidase (LiP) producing strain LD-5. The strain was isolated from pulp and paper mill effluent contaminated site. Biochemical and 16S rDNA gene sequence analysis suggested that strain LD-5 belonged to the Serratia liquefaciens. The strain LD-5 effectively reduced pollution parameters (colour 72%, lignin 58%, COD 85% and phenol 95%) of real effluent after 144h of treatment at 30°C, pH 7.6 and 120rpm. Extracellular LiP produced by S. liquefaciens during effluent decolourisation was purified to homogeneity using ammonium sulfate (AMS) precipitation and DEAE cellulose column chromatography. The molecular weight of the purified lignin peroxidase was estimated to be ∼28kDa. Optimum pH and temperature for purified lignin peroxidase activity were determined as pH 6.0 and 40°C, respectively. Detoxified effluent was evaluated for residual toxicity by alkaline single cell (comet) gel electrophoresis (SCGE) assay using Saccharomyces cerevisiae MTCC 36 as model organism. The toxicity reduction to treated effluent was 49.4%. These findings suggest significant potential of S. liquefaciens for bioremediation of pulp and paper mill effluent.

Understanding the specificity of serpin-protease complexes through interface analysis.

Serpins such as antithrombin, heparin cofactor II, plasminogen activator inhibitor, antitrypsin, antichymotrypsin, and neuroserpin are involved in important biological processes by inhibiting specific serine proteases. Initially, the protease recognizes the mobile reactive loop of the serpin eliciting conformational changes, where the cleaved loop together with the protease inserts into ß-sheet A, translocating the protease to the opposite side of inhibitor leading to its inactivation. Serpin interaction with proteases is governed mainly by the reactive center loop residues (RCL). However, in some inhibitory serpins, exosite residues apart from RCL have been shown to confer protease specificity. Further, this forms the basis of multi-specificity of some serpins, but the residues and their dimension at interface in serpin-protease complexes remain elusive. Here, we present a comprehensive structural analysis of the serpin-protease interfaces using bio COmplexes COntact MAPS (COCOMAPS), PRotein Interface Conservation and Energetics (PRICE), and ProFace programs. We have carried out interface, burial, and evolutionary analysis of different serpin-protease complexes. Among the studied complexes, non-inhibitory serpins exhibit larger interface region with greater number of residue involvement as compared to the inhibitory serpins. On comparing the multi-specific serpins (antithrombin and antitrypsin), a difference in the interface area and residue number was observed, suggestive of a differential mechanism of action of these serpins in regulating their different target proteases. Further, detailed study of these multi-specific serpins listed few essential residues (common in all the complexes) and certain specificity (unique to each complex) determining residues at their interfaces. Structural mapping of interface residues suggested that individual patches with evolutionary conserved residues in specific serpins determine their specificity towards a particular protease.