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Biology subjects

Majumdar, M.

Publications and source records attributed to Majumdar, M..

5 recordsLinked to original sources

SPRINT-MS: A high-throughput platform for identifying protein-protein interactions using pooled IP-MS and sparse signal recovery.

We present SPRINT-MS (SParse Reconstruction of INTeractions by Mass Spectrometry), an integrated experimental and computational platform to accelerate the discovery of protein-protein interactions (PPIs). PPIs, which govern critical cellular and physiological processes such as development and disease, form extensive networks that vary across time, conditions, and cell types, creating a complex, high-dimensionality problem. Thus, there is a pressing need for universally applicable tools capable of mapping and quantifying PPI networks and their context-dependent dynamics with high efficiency. SPRINT-MS combines an innovative antibody (or lysate) pooling scheme, immunopurification-mass spectrometry (IP-MS), and a novel sparse signal reconstruction algorithm to enable pooled PPI capture experiments. This approach increases throughput by an order of magnitude, while reducing sample input requirements. We demonstrate that SPRINT-MS, applied to 30 bait proteins of interest via either antibody or lysate pooling, is comparable to standard individual IP-MS experiments in the identification of PPIs and recapitulation of known interactions.

molecular biology↗

Automated detection and classification of polioviruses from nanopore sequencing reads using piranha

Widespread surveillance, rapid detection and appropriate intervention will be critical for successful eradication of poliovirus. With deployable next-generation sequencing (NGS) approaches, such as Oxford Nanopore Technologies MinION, the time from sample to result can be significantly reduced compared to cell culture and Sanger sequencing. We developed piranha (poliovirus investigation resource automating nanopore haplotype analysis) to aid routine poliovirus testing of both stool and environmental samples and alleviate the bioinformatic bottleneck that often exists for labs adopting novel NGS approaches. Piranha can be used for efficient intratypic differentiation of poliovirus serotypes, for classification of Sabin-like polioviruses and for detection of wild-type and vaccine derived polioviruses. It produces interactive, distributable html reports, as well as summary csv files and consensus poliovirus FASTA sequences. The reports describe each nanopore sequencing run with interpretable plots enabling researchers to easily detect the presence of poliovirus in samples and quickly disseminate their results.

bioinformatics↗

Loss of CPAP expression promotes sustained EGFR signaling and Epithelial-Mesenchymal Transition in oral cancer cells

Oral squamous cell carcinoma (OSCC) is the most common type of head and neck squamous cell carcinoma (HNSCC). Altered epidermal growth factor receptor (EGFR) levels can contribute to tumor metastasis and resistance to therapies. The epithelial-mesenchymal transition (EMT), by which epithelial cells acquire a mesenchymal and invasive phenotype, contributes significantly to tumor metastasis in OSCC, and EGFR signaling is known to promote this process. Microtubule inhibition therapies cause EGFR inactivation or increase the sensitivity to EGFR targeting drugs in various cancers including OSCC. In this study, using OSCC model, we show that loss of a microtubule/tubulin binding protein, centrosomal protein 4.1-associated protein (CPAP), which is critical for centriole biogenesis and normal functioning of centrosome, caused an increase in the EGFR levels and signaling and, enhanced the EMT features and invasiveness of OSCC cells. Further, depletion of CPAP increased the tumorigenicity of these cells in a xeno-transplant model. Importantly, CPAP loss-associated EMT features and invasiveness of multiple OSCC cells were attenuated upon depletion of EGFR in them. Overall, our novel observations suggest that in addition to its previously known regulatory role in centrosome biogenesis and function, CPAP plays an important role in suppressing EMT and tumorigenesis in OSCC by regulating EGFR homeostasis and signaling.

cancer biology↗

Rapid and sensitive direct detection and identification of poliovirus from stool and environmental surveillance samples using nanopore sequencing

Global poliovirus surveillance involves virus isolation from stool and environmental samples, intratypic differential (ITD) by PCR and sequencing of the VP1 region to distinguish vaccine (Sabin), vaccine-derived and wild-type polioviruses and ensure an appropriate response. This cell-culture algorithm takes 2-3 weeks on average between sample receipt and sequencing. Direct detection of viral RNA using PCR allows faster detection but has traditionally faced challenges related to poor sensitivity and difficulties in sequencing common samples containing poliovirus and enterovirus mixtures. We present a nested PCR and nanopore sequencing protocol that allows rapid (<3 days) and sensitive direct detection and sequencing of polioviruses in stool and environmental samples. We developed barcoded primers and a real-time analysis platform that generate accurate VP1 consensus sequences from multiplexed samples. The sensitivity and specificity compared with cell-culture were 90.9% (95% Confidence Interval: 75.7-98.1%) and 99.2% (95.5-100.0%) for wild-type 1 poliovirus, 92.5% (79.6-98.4%) and 98.7% (95.4-99.8%) for vaccine and vaccine-derived serotype 2 poliovirus, and 88.3% (81.2-93.5%) and 93.2% (88.6-96.3%) for Sabin 1 and 3 poliovirus alone or in mixtures when tested on 155 stool samples in Pakistan. Variant analysis of sequencing reads also allowed identification of polioviruses and enteroviruses in artificial mixtures and was able to distinguish complex mixtures of polioviruses in environmental samples. The median identity of consensus nanopore sequences with Sanger or Illumina sequences from the same samples was >99.9%. This novel method shows promise as a faster and safer alternative to cell-culture for the detection and real-time sequencing of polioviruses in stool and environmental samples.

microbiology↗

Detection of Enterovirus D68 in wastewater samples from the United Kingdom during outbreaks reported globally between 2015 and 2018

Detection of enterovirus D68 (EV-D68) in wastewater samples from the UK between December 2014 and December 2018 showed a marked seasonal distribution with a high proportion of samples containing EV-D68 during periods when identification of this virus in clinical samples was most common. This includes a recent upsurge of EV-D68 detection in respiratory samples from the United Kingdom between August and December 2018 associated with cases of acute flaccid myelitis, following similar reports in the USA. Phylogenetic analysis of EV-D68 sewage strains demonstrated that strains belonging to distinct genetic clades followed the same temporal distribution as that observed for EV-D68 clinical strains in the UK and that they showed very close genetic relationship with EV-D68 strains circulating elsewhere in the world during the same periods. The results demonstrated a clear association between detecting EV-D68 in wastewater and finding it in clinical samples which was somehow unexpected given that EV-D68 is rarely detected in stool samples. We conclude that the use of environmental surveillance is a valuable tool to detect and monitor outbreaks due to EV-68 infection.

microbiology↗