Leishmania donovani modulates host miRNAs regulating cholesterol biosynthesis for its survival.

Cholesterol reduction by intracellular protozoan parasite Leishmania donovani, causative agent of leishmaniasis, impairs antigen presentation, pro-inflammatory cytokine secretion and host-protective membrane-receptor signaling in macrophages. Here, we studied the miRNA mediated regulation of cholesterol biosynthetic genes to understand the possible mechanism of Leishmania donovani-inducedcholesterol reduction and therapeutic importance of miRNAs in leishmaniasis. System-scale genome-wide microtranscriptome screening was performed to identify the miRNAs involved in the regulation of expression of key cholesterol biosynthesis regulatory genes through miRanda3.0. 11 miRNAs out of 2823, showing complementarity with cholesterol biosynthetic genes werefinallyselected for expression analysis. These selected miRNAs were differentially regulated in THP-1 derived macrophages and in primary human macrophages by L. donovani. Correlation of expression and target validation through luciferase assay suggested two key miRNAs, hsa-miR-1303 and hsa-miR-874-3pregulating the key genes hmgcr and hmgcs1 respectively. Inhibition of hsa-mir-1303 and hsa-miR-874-3p augmented the expression of targets and reduced the parasitemia in macrophages.This study will also provide the platform for the development of miRNA-based therapy against leishmaniasis.

FRET-based probe for ratiometric detection and imaging of folic acid in real-time.

Inadequate folic acid intake is linked to diseases such as megaloblastic anemia, neural tube defects, and hyperhomocysteinemia, increasing the risk of vascular disease and thrombosis. Folic acid, a cofactor in various enzymes, can be produced by plants and bacteria, but not by humans and other animals. L-5-methyl-tetrahydrofolate (L-5-methyl-THF) is the primary dietary folate form, transported in circulation for cellular metabolism. Traditional methods of determining folic acid levels are unreliable and time-consuming. SenFol (Sensor for folic acid) is a fluorescence resonance energy transfer (FRET)-based nanosensor that we have developed by inserting folic acid-binding protein (FolT) as the folate detecting domain between the pair of enhanced cyan fluorescent protein (ECFP) and Venus. The developed sensor is highly specific, produces a quick signal, which is pH stable, and delivers precise, ratiometric readings in cell-based experiments. The projected affinity score of folic acid with FolT was -7.4 kcal/mol. The apparent affinity (Kd) of SenFol for folic acid is 28.49 × 10-9 M, with a detection range of 5 × 10-9 M to 5 × 10-7 M, and a maximum FRET ratio change of 0.45. WT SenFol, a highly efficient folic acid nanosensor, can dynamically detect intracellular folic acid content in E. coli, yeast, and HEK-293 T cells, confirming its potential.

Real-Time Monitoring of Selenium in Living Cells by Fluorescence Resonance Energy Transfer-Based Genetically Encoded Ratiometric Nanosensors.

Selenium is a component of selenoproteins, which plays a crucial role in cellular redox homeostasis, thyroid metabolism, and DNA synthesis. Selenium has pleiotropic effects like antioxidant and anti-inflammatory activities; however, excess intake of selenium can imbalance such processes. The effects of selenium on human health are numerous and complex, demanding additional research to monitor the flux rate of selenium. Here, we have created a noninvasive and highly efficient genetically encoded fluorescence resonance energy transfer (FRET)-based nanosensor, SelFS (Selenium FRET-Sensor), for real-time monitoring of selenium at the cellular and subcellular levels. The construct of the nanosensor contains a selenium-binding protein (SeBP) as the selenium-detecting element inserted between the green fluorescent protein variants enhanced cyan fluorescent protein and Venus. In the presence of selenium, SelFS brings a conformational change, which is seen in the form of FRET. In vitro studies showed that SelFS is highly specific and selective for selenium and stable at an altered pH range from 5.0 to 8.0. SelFS is a flexible and dynamic tool for the detection of selenium in both prokaryotes and eukaryotes in a noninvasive way, with a binding constant (K d) of 0.198 × 10-6 M as compared to its mutants. The developed nanosensor can provide us a reporter tool for a wide range of industrial and environmental applications, which will help us to understand its functions in biological systems.

Combined Multiomics and In Silico Approach Uncovers PRKAR1A as a Putative Therapeutic Target in Multi-Organ Dysfunction Syndrome.

Despite all epidemiological, clinical, and experimental research efforts, therapeutic concepts in sepsis and sepsis-induced multi-organ dysfunction syndrome (MODS) remain limited and unsatisfactory. Currently, gene expression data sets are widely utilized to discover new biomarkers and therapeutic targets in diseases. In the present study, we analyzed MODS expression profiles (comprising 13 sepsis and 8 control samples) retrieved from NCBI-GEO and found 359 differentially expressed genes (DEGs), among which 170 were downregulated and 189 were upregulated. Next, we employed the weighted gene co-expression network analysis (WGCNA) to establish a MODS-associated gene co-expression network (weighted) and identified representative module genes having an elevated correlation with age. Based on the results, a turquoise module was picked as our hub module. Further, we constructed the PPI network comprising 35 hub module DEGs. The DEGs involved in the highest-confidence PPI network were utilized for collecting pathway and gene ontology (GO) terms using various libraries. Nucleotide di- and triphosphate biosynthesis and interconversion was the most significant pathway. Also, 3 DEGs within our PPI network were involved in the top 5 significantly enriched ontology terms, with hypercortisolism being the most significant term. PRKAR1A was the overlapping gene between top 5 significant pathways and GO terms, respectively. PRKAR1A was considered as a therapeutic target in MODS, and 2992 ligands were screened for binding with PRKAR1A. Among these ligands, 3 molecules based on CDOCKER score (molecular dynamics simulated-based score, which allows us to rank the binding poses according to their quality and to identify the best pose for each system) and crucial interaction with human PRKAR1A coding protein and protein kinase-cyclic nucleotide binding domains (PKA RI alpha CNB-B domain) via active site binding residues, viz. Val283, Val302, Gln304, Val315, Ile327, Ala336, Ala337, Val339, Tyr373, and Asn374, were considered as lead molecules.

Genetically Encoded FRET-Based Nanosensor for Real-Time Monitoring of A549 Exosomes: Early Diagnosis of Cancer.

Exosomes contain a plethora of unique disease biomarkers involving cellular homeostasis, infection dissemination, cancer development, and cardiac diseases. Exosomes originating from cancer cells have promising biomarkers for the early detection and assessment of the therapeutic response to cancer. The exosomal epidermal growth factor receptor (EGFR) is a potential biomarker which is overexpressed in cancer; thus, the level of EGFR expression is investigated by so many methods in a liquid and solid biopsy. The optimal method for isolating pure exosomal EGFRs has not been well understood so far. Current approaches are complicated and time-consuming, therefore hampering their clinical applications. Here, we demonstrate the creation of an innovative fluorescence resonance energy transfer (FRET) sensor, named ExoSen (exosome sensor), which can be implemented to determine the concentration of exosomal EGFRs at in vitro as well as in vivo levels. In this study, a sensing element for A549 exosomes, mitogen-inducible gene 6 (MIG6), has been employed between the FRET pair ECFP and Venus. MIG6 binding to ExoSen induced a conformational change that can be monitored by a variation in the FRET ratio. Moreover, the developed sensor, expressed in bacterial, yeast, and HEK-293T cells, demonstrates an increased FRET ratio with the addition of A549 exosomes, which can quantify the A549 exosomes noninvasively. The ExoSen enables rapid detection of A549 exosomes with great sensitivity at a concentration of 3.5 × 109 particles/mL. ExoSen is stable to pH fluctuations and provides a highly accurate, real-time optical readout in cell-based experiments by using confocal microscopy.

Biochemical and biophysical analysis of the interaction of a recombinant form of Staphylococcus aureus enolase with plasminogen.

Aim: Pathogenic invasion of Staphylococcus aureus is critically dependent on host plasminogen activation. Materials & methods: The pathophysiological implications of the interactions between S. aureus recombinant enolase and host plasminogen were investigated. The effects of mutation and small synthetic peptide inhibitors on interactions were assessed. Results: In vitro, the S. aureus recombinant enolase exists as a catalytically active fragile octamer and a robust dimer. The dimer interacts with the host plasminogen on the S. aureus surface. Conclusion: The interaction of host plasminogen and S. aureus enolase might mediate bacterial adherence to the host, activate the plasminogen with the help of plasminogen activators and prevent α2-antiplasmin-mediated inhibition of plasmin. Incorporating mutant and synthetic peptides inhibited the interactions and their associated pathophysiological consequences.

A district-level vulnerability assessment of next COVID-19 variant (Omicron BA.2) in Uttarakhand using quantitative SWOT analysis.

COVID-19 has had an impact on the entire humankind and has been proved to spread in deadly waves. As a result, preparedness and planning are required to better deal with the epidemic's upcoming waves. Effective planning, on the other hand, necessitates detailed vulnerability assessments at all levels, from the national to the state or regional. There are several issues at the regional level, and each region has its own features. As a result, each region needs its own COVID-19 vulnerability assessment. In terms of climate, terrain and demographics, the state of Uttarakhand differs significantly from the rest of India. As a result, a vulnerability assessment of the next COVID-19 variation (Omicron BA.2) is required for district-level planning to meet regional concerns. A total of 17 variables were chosen for this study, including demographic, socio-economic, infrastructure, epidemiological and tourism-related factors. AHP was used to compute their weights. After applying min-max normalisation to the data, a district-level quantitative SWOT is created to compare the performance of 13 Uttarakhand districts. A COVID-19 vulnerability index (normalised R i ) ranging between 0 and 1 was produced, and district-level vulnerabilities were mapped. Quantitative SWOT results depict that Dehradun is a best performing district followed by Haridwar, while Bageshwar, Rudra Prayag, Champawat and Pithoragarh are on the weaker side and the normalised Ri proves Dehradun, Nainital, Champawat, Bageshwar and Chamoli to be least vulnerable to COVID-19 (normalised R i ≤ 0.25) and Pithoragarh to be the most vulnerable district (normalised R i > 0.90). Pauri Garwal and Uttarkashi are moderately vulnerable (normalised R i 0.50 to 0.75).

Real time optical detection of gold in living cells through genetically-encoded probe.

To study the efflux of gold (Au) in living cells, a genetically encoded fluorescence resonance energy transfer (FRET)-based sensor has been developed. The gold-sensing domain GolB from Salmonella typhimurium has been fused to the N- and C-termini of the FRET pair enhanced cyan fluorescent protein (ECFP) and Venus respectively. In living cells, this probe is highly selective and sensitive to gold and it can withstand changes in variable pH ranges. GolSeN-25, the most efficient sensor variant, binds gold with an affinity (K d) of 0.3 × 10-6 M, covering gold concentrations of nM to µM, and can be used for non-invasive real-time in vivo gold measurement in living cells. A simple and sensitive FRET probe was designed for the detection of gold with high selectivity and can be applied to the analysis of real samples.

Integrated transcriptomic and regulatory network analyses uncovers the role of let-7b-5p, SPIB, and HLA-DPB1 in sepsis.

Sepsis has affected millions of populations of all age groups, locations, and sexes worldwide. Immune systems, either innate or adaptive are dysregulated due to the infection. Various biomarkers are present to date, still sepsis is a primary cause of mortality. Globally, post-operative body infections can cause sepsis and septic shock in ICU. Abnormal antigen presentation to T-cells leads to a dysregulated immune system. miRNAs are sparkly evolved as biomarkers due to their high sensitivity and efficiency. In this work, we analyzed high-throughput mRNA data collected from Gene Expression Omnibus (GEO) and linked it to significant miRNAs and TFs using a network-based approach. Protein-protein interaction (PPI) network was constructed using sepsis-specific differentially expressed genes (DEGs) followed by enrichment analyses and hub module detection. Sepsis-linked decrease transcription of the classical HLA gene such as HLA-DPB1 and its interplay with miR-let-7b-5p and transcription factor SPIB was observed. This study helped to provide innovative targets for sepsis.

Integration of chemokine signaling with non-coding RNAs in tumor microenvironment and heterogeneity in different cancers.

Chemokines are small secreted proteins that regulate the immune system by signaling through chemokine receptors to induce immune cell migration, motility, and infiltration into the tissue. Altered chemokine/receptor expression is associated with numerous inflammatory diseases, and more recently in non-immune cell diseases like cancer. Emerging new studies demonstrate that chemokines can directly modulate the tumor microenvironment (TME) to assist tumorigenesis by regulating proinflammatory signaling, immune cell infiltration,and metastasis. However, the diversity and complexity in the regulation of chemokine expression and how chemokine receptor signaling influences TME needs comprehensive understanding. One mechanistic pathway that has shown promising early results in targeting tumor progression is the non-coding RNAs (ncRNAs). These are widely expressed and designated as prime gene regulatory factors in tumors and the immune system. Notably, ncRNAs have been implicated in regulating chromatin stability, translation of cytoplasmic mRNAs, and the functional regulation of membrane-less nuclear bodies, which are significant pathways implicated in tumorigenesis. Tissue-specific patterns of expression of ncRNAs have suggested their role as potential cancer biomarkers, providing a suitable rationale for targeting them clinically. In this review, we discuss the recent findings which demonstrate the role of differential expression of chemokines and ncRNA in modulating TME during tumor progression. We also discuss the communication between tumor and immune effector cells via chemokine/ncRNAs and identify their potential as novel therapeutic targets.

A GIS-based novel approach for suitable sanitary landfill site selection using integrated fuzzy analytic hierarchy process and machine learning algorithms.

Disposal of waste without treatment is the least preferable way of sustainable solid waste management (SWM). But most cities in developing nations still use open dumps, causing negative impacts on the environment and human health. This study offered a novel approach for selecting landfill sites and sustainable SWM in Aligarh city, India. This was done through data collection, selecting models for criterion weighting, and validation. In order to prepare a landfill site suitability map, a geographic information system (GIS)-based ensemble fuzzy analytic hierarchy process-support vector machine (FAHP-SVM) and fuzzy analytic hierarchy process-random forest (FAHP-RF) models were implemented. Considering the previous studies and the study area characteristics, eighteen thematic layers were selected. The result revealed that land value; distance from residential roads, hospitals and clinics, and waste bins; and normalized difference built-up index (NDBI) have a fuzzy weight greater than 0.10, indicating significant factors. In contrast, land elevation, land slope, surface temperature, soil moisture index, normalized difference vegetation index (NDVI), and urban classification have a zero fuzzy weight, indicating these criteria have no importance. The result further revealed that FAHP-RF with an area under curve (AUC) value of 0.91 is the more accurate model than FAHP-SVM. According to the final weight-based overlay result, seven potential landfill sites were identified, out of which three were determined as most suitable by considering current land cover, public opinions, and environmental and economic concerns. This research proposed a zonal division model based on landfill sites location for sustainable SWM in Aligarh city. However, the findings may provide a guideline to the decision-makers and planners for optimal landfill site selection in other cities of developing countries.

Development of Oxadiazole-Sulfonamide-Based Compounds as Potential Antibacterial Agents.

In this work, substituted 1,2,4-oxadiazoles (OX1-OX27) were screened against five bacterial strains, identified to be OX7 and OX11 as growth inhibitors with minimum inhibitory concentration (MIC) values of 31.25 and 15.75 µg/mL, respectively. The growth inhibitory property of OX7 and OX11 was further validated by disk diffusion, growth curve, and time kill curve assays. Both disrupted biofilm formation with 92-100% reduction examined by the XTT assay were further visualized by scanning electron microscopy analysis. These compounds in combination with ciprofloxacin also exhibit synergy against Escherichia coli cells. With insignificant cytotoxic behavior on HEK293 cells, human red blood cells, and Galleria mellonella larvae, OX11 was tested against 28 multidrug resistant environmental isolates of bacteria and showed inhibition of Kluyvera georgiana and Citrobacter werkmanii strains with 32 and 16 µg/mL MIC values, respectively. The synergistic behavior of OX11 with ampicillin showed many fold reductions in MIC values against K. georgiana and Klebsiella pneumoniae multidrug resistant strains. Further, transmission electron microscopy analysis of OX11-treated E. coli cells showed a significantly damaged cell wall, which resulted in the loss of integrity and cytosolic oozing. OX11 showed significant changes in the secondary structure of human serum albumin (HSA) in the presence of OX11, enhancing HSA stability. Overall, the study provided a suitable core for further synthetic alterations and development as an antibacterial agent.

FRET-Based Genetically Encoded Sensor to Monitor Silver Ions.

Silver is commonly used in wound dressing, photography, health care products, laboratories, pharmacy, biomedical devices, and several industrial purposes. Silver (Ag+) ions are more toxic pollutants widely scattered in the open environment by natural processes and dispersed in soil, air, and water bodies. Ag+ binds with metallothionein, macroglobulins, and albumins, which may lead to the alteration of various enzymatic metabolic pathways. To analyze the uptake and metabolism of silver ions in vitro as well as in cells, a range of high-affinity fluorescence-based nanosensors has been constructed using a periplasmic protein CusF, a part of the CusCFBA efflux complex, which is involved in providing resistance against copper and silver ions in Escherichia coli. This nanosensor was constructed by combining of two fluorescent proteins (donor and acceptor) at the N- and C-terminus of the silver-binding protein (CusF), respectively. SenSil (WT) with a binding constant (K d) of 5.171 µM was more efficient than its mutant variants (H36D and F71W). This nanosensor allows monitoring the level of silver ions in real time in prokaryotes and eukaryotes without any disruption of cells or tissues.

Designing and Development of FRET-Based Nanosensor for Real Time Analysis of N-Acetyl-5-Neuraminic Acid in Living Cells.

N-acetyl-5-neuraminic acid (NeuAc) plays crucial role in improving the growth, brain development, brain health maintenance, and immunity enhancement of infants. Commercially, it is used in the production of antiviral drugs, infant milk formulas, cosmetics, dietary supplements, and pharmaceutical products. Because of the rapidly increasing demand, metabolic engineering approach has attracted increasing attention for NeuAc biosynthesis. However, knowledge of metabolite flux in biosynthetic pathways is one of the major challenges in the practice of metabolic engineering. So, an understanding of the flux of NeuAc is needed to determine its cellular level at real time. The analysis of the flux can only be performed using a tool that has the capacity to measure metabolite level in cells without affecting other metabolic processes. A Fluorescence Resonance Energy Transfer (FRET)-based genetically-encoded nanosensor has been generated in this study to monitor the level of NeuAc in prokaryotic and eukaryotic cells. Sialic acid periplasmic binding protein (SiaP) from Haemophilus influenzae was exploited as a sensory element for the generation of nanosensor. The enhanced cyan fluorescent protein (ECFP) and Venus were used as Fluroscence Resonance Energy Transfer (FRET) pair. The nanosensor, which was termed fluorescent indicator protein for sialic acid (FLIP-SA), was successfully transformed into, and expressed in Escherichia coli BL21 (DE3) cells. The expressed protein of the nanosensor was isolated and purified. The purified nanosensor protein was characterized to assess the affinity, specificity, and stability in the pH range. The developed nanosensor exhibited FRET change after addition to NeuAc. The developed nanosensor was highly specific, exhibited pH stability, and detected NeuAc levels in the nanomolar to milimolar range. FLIP-SA was successfully introduced in bacterial and yeast cells and reported the real-time intracellular levels of NeuAc non-invasively. The FLIP-SA is an excellent tool for the metabolic flux analysis of the NeuAc biosynthetic pathway and, thus, may help unravel the regulatory mechanism of the metabolic pathway of NeuAc. Furthermore, FLIP-SA can be used for the high-throughput screening of E. coli mutant libraries for varied NeuAc production levels.

The role of mitophagy in pulmonary sepsis.

Sepsis is a systemic inflammatory disease with an unacceptably high mortality rate caused by an infection or trauma that involves both innate and adaptive immune systems. Inflammatory events activate different downstream pathways leading to tissue damage and ultimately multi-organ failure. Mitochondria are responsible for cellular energy, thermoregulation, metabolite biosynthesis, intracellular calcium regulation, and cell death. Damaged mitochondria induce the high Ca2+ influx through mitochondrial calcium uniporter (MCU). It also generates excessive Reactive oxygen species (ROS) and releases mtDNA into the cytoplasm, which causes induction of NLRP3 inflammasome and apoptosis. Mitophagy (Autophagy of damaged mitochondria) controls mitochondrial dynamics and function. It also maintains cellular homeostasis. This review is about how pulmonary sepsis affects the body. What is the aftermath of sepsis, and how mitophagy affects Acute Lung Injury and macrophage polarisation to overcome the damages.

Vitamin D and its therapeutic relevance in pulmonary diseases.

Vitamin D is customarily involved in maintaining bone and calcium homeostasis. However, contemporary studies have identified the implication of vitamin D in several cellular processes including cellular proliferation, differentiation, wound healing, repair and regulatory systems inclusive of host defence, immunity, and inflammation. Multiple studies have indicated corelations between low serum levels of vitamin D, perturbed pulmonary functions and enhanced incidences of inflammatory diseases. Almost all of the pulmonary diseases including acute lung injury, cystic fibrosis, asthma, COPD, Pneumonia and Tuberculosis, all are inflammatory in nature. Studies have displayed strong inter-relations with vitamin D deficiency and progression of lung disorders; however, the underlying mechanism is still unknown. Vitamin D has emerged to possess inhibiting effects on pulmonary inflammation while exaggerating innate immune defenses by strongly influencing functions of inflammatory cells including dendritic cells, monocyte/macrophages, T cells, and B cells along with structural epithelial cells. This review dissects the effects of vitamin D on the inflammatory cells and their therapeutic relevance in pulmonary diseases. Although, the data obtained is very limited and needs further corroboration but presents an exciting area of further research. This is because of its ease of supplementation and development of personalized medicine which could lead us to an effective adjunct and cost-effective method of therapeutic modality for highly fatal pulmonary diseases.

A perspective on the isolation and characterization of extracellular vesicles from different biofluids.

Extracellular vesicles (EVs) are small membrane-bound particles, which include exosomes, micro vesicles (MVs) and various-sized vesicles, released by healthy and diseased cells. EVs also include other vesicular structures, such as large apoptotic bodies (1-5 µm), as well as membrane particles (50-80 nm) originating from the plasma membrane. However, exosomes are nanosize (≈30-100 nm) extracellular vesicles of endocytic origin that are bud-off by most types of cells and circulate in bodily fluids. Extracellular nanovesicles contain a large variety of biomolecules, including miRNA, RNA, DNA, proteins, signaling peptides and lipids, that can have diagnostic and therapeutic value. The spectrum of the existing scientific interest in extracellular nanovesicles is comprehensive, which ranges from understanding their functions and pathways to their potential clinical usage. EVs can be obtained from different body fluids with minimally invasive techniques (e.g., urine, plasma, serum), so they are most useful in disease diagnosis. High yield and purity contribute to the accurate diagnosis of various diseases, but damaged EVs and impurities can cause misinterpreted results. Over the last decade, a plethora of approaches have been developed for examining EVs using optical and non-optical tools. However, EV isolation methods have different yields and purities. Moreover, the isolation method that is most appropriate to maximize EVs recovery depends on the different experimental situations. This review explores the emerging use of micro and nano-technologies to isolate and characterize exosomes and microvesicles (MVs) from different biological samples, and the application of these technologies for the monitoring and diagnosis of different pathological conditions.

A Non-Invasive Tool for Real-Time Measurement of Sulfate in Living Cells.

Sulfur (S) is an essential element for all forms of life. It is involved in numerous essential processes because S is considered as the primary source of one of the essential amino acids, methionine, which plays an important role in biological events. For the control and regulation of sulfate in a metabolic network through fluxomics, a non-invasive tool is highly desirable that opens the door to monitor the level of the sulfate in real time and space in living cells without fractionation of the cells or tissue. Here, we engineered a FRET (fluorescence resonance energy transfer) based sensor for sulfate, which is genetically-encoded and named as FLIP-SP (Fluorescent indicator protein for sulfate). The FLIP-SP can measure the level of the sulfate in live cells. This sensor was constructed by the fusion of fluorescent proteins at the N- and C-terminus of sulfate binding protein (sbp). The FLIP-SP is highly specific to sulfate, and showed pH stability. Real-time monitoring of the level of sulfate in prokaryotic and eukaryotic cells showed sensor bio-compatibility with living cells. We expect that this sulfate sensor offers a valuable strategy in the understanding of the regulation of the flux of sulfate in the metabolic network.

Design, synthesis & biological evaluation of ferulic acid-based small molecule inhibitors against tumor-associated carbonic anhydrase IX.

Carbonic anhydrase IX (CAIX) is an emerging drug target for hypoxia associated cancers. To identify potent and selective inhibitors of CAIX, a small library of ferulic acid (FA) derivatives bearing triazole moiety has been designed, synthesized and evaluated against different human CA isoforms (CAII, CAVA & CAIX). Though most of the compounds showed CAIX inhibition in the micromolar range, compound 7i selectively inhibits CAIX in the nanomolar range (IC50 = 24 nM). In silico analysis revealed binding of 7i with the catalytically important amino acid residues of CAIX. Further, cell-based studies indicate that 7i inhibits the activity of CAIX, decreases the epithelial to mesenchymal transitions, induces apoptosis, inhibits cell migration and colonization potential of cancer cells. Taken together, these results emphasized the use of 7i as a prospective pharmacological lead molecule in CAIX targeted anticancer therapeutics.

Enhanced sensitivity and detection range of FRET-based vitamin B12 nanosensor.

Vitamin B12 (cobalamin) is a cobalt-containing compound that acts as an essential co-factor for various enzymes involved in the metabolic processes of the living cells. The constructed FRET Sensor for Vitamin Anemia Linked (SenVitAL) displayed marginal FRET efficiency. Here, we report the development of a molecular SenVitAL containing enhanced cyan fluorescent protein (ECFP) and venus as FRET pair to improve the FRET efficiency for optical imaging and screening of already developed sensor by our group. The sensor is the improved version of previously reported SenVitAL and consists of ECFP/venus as FRET pair instead of the originally used pair CFP/YFP. To increase the physiological range of vitamin B12 measurement, affinity mutants were created. Compared to the wild type, SenVitAL-5 with W44Q mutation has higher affinity and displayed large dynamic detection range (0.10-480 µM) in response to vitamin B12 binding. For cell-based monitoring and dynamic measurement of vitamin B12 flux rates, SenVitAL-5 was successfully expressed in cytosol of yeast and mammalian cells. Changes in the emission intensities of the two fluorophores were detected using confocal microscopy in both cell types in response to vitamin B12. With the addition of 50 µM extracellular vitamin B12 to the cells, the emission intensity of venus increased and that of ECFP decreased over the time. Furthermore, the results show that the variant SenVitAL-5 measures the vitamin B12 in a concentration-dependent manner, showing the resulting increase in the FRET ratio and thus confirming its utility as an ideal fluorescent indicator for the detection of vitamin B12 in eukaryotic systems in real time.