Novel low-cost sensor for human bite force measurement

This paper presents the design and development of a low cost and reliable maximal voluntary bite force sensor which can be manufactured in-house by using an acrylic laser cutting machine. The sensor has been designed for ease of fabrication, assembly, calibration, and safe use. The sensor is capable of use within an hour of commencing production, allowing for rapid prototyping/modifications and practical implementation. The measured data shows a good linear relationship between the applied force and the electrical resistance of the sensor. The output signal has low drift, excellent repeatability, and a large measurable range of 0 to 700 N. A high signal-to-noise response to human bite forces was observed, indicating the high potential of the proposed sensor for human bite force measuremen

STK11 Prevents Invasion Through STAT3/5 and FAK Repression in Cutaneous Melanoma.

The serine/threonine kinase 11 (STK11/LKB1) is a tumor suppressor involved in metabolism and cell motility. In BRAFV600E melanoma, STK11 is inactivated by ERK and RSK, preventing it from binding and activating AMPK and promoting melanoma cell proliferation. Although STK11 mutations occur in 5-10% of cutaneous melanoma, few functional studies have been performed. By knocking out STK11 with CRISPR/Cas9 in two human BRAF-mutant melanoma cell lines, we found that STK11-loss reduced the sensitivity to a BRAF inhibitor (BRAFi). More strikingly, STK11 loss led to an increased invasive phenotype in both 3-dimensional spheroids and in vivo zebrafish xenograft models. STK11 overexpression consistently reverted the invasive phenotype. Interestingly, STK11 knockout increased invasion also in an NRAS-mutant melanoma cell line. Furthermore, while STK11 was expressed in primary human melanoma tumors, its expression significantly decreased in melanoma metastases especially in brain metastases. In the STK11-knockout cells we observed increased activating phosphorylation of STAT3/5 and FAK. Using inhibitors of STAT3/5 and FAK, we reverted the invasive phenotype in both BRAF and NRAS mutated cells. Our findings confirm an increased invasive phenotype upon STK11-inactivation in BRAF and NRAS-mutant cutaneous melanoma that can be targeted by STAT3/5 and FAK-inhibition

STK11 Prevents Invasion through Signal Transducer and Activator of Transcription 3/5 and FAK Repression in Cutaneous Melanoma

The STK11/LKB1 is a tumor suppressor involved in metabolism and cell motility. In BRAF$^{V600E}$ melanoma, STK11 is inactivated by extracellular signal‒regulated kinase and RSK, preventing it from binding and activating adenosine monophosphate-activated protein kinase and promoting melanoma cell proliferation. Although STK11 mutations occur in 5‒10% of cutaneous melanoma, few functional studies have been performed. By knocking out STK11 with CRISPR/Cas9 in two human BRAF-mutant melanoma cell lines, we found that STK11 loss reduced the sensitivity to a BRAF inhibitor. More strikingly, STK11 loss led to an increased invasive phenotype in both three-dimensional spheroids and in vivo zebrafish xenograft models. STK11 overexpression consistently reversed the invasive phenotype. Interestingly, STK11 knockout increased invasion also in an NRAS-mutant melanoma cell line. Furthermore, although STK11 was expressed in primary human melanoma tumors, its expression significantly decreased in melanoma metastases, especially in brain metastases. In the STK11-knockout cells, we observed increased activating phosphorylation of signal transducer and activator of transcription 3/5 and FAK. Using inhibitors of signal transducer and activator of transcription 3/5 and FAK, we reversed the invasive phenotype in both BRAF- and NRAS-mutated cells. Our findings confirm an increased invasive phenotype on STK11 inactivation in BRAF- and NRAS-mutant cutaneous melanoma that can be targeted by signal transducer and activator of transcription 3/5 and FAK inhibition

A Comparative Study of Real-Time RT-PCR–Based SARS-CoV-2 Detection Methods and Its Application to Human-Derived and Surface Swabbed Material

Real-time RT-PCR remains a gold standard in the detection of various viral diseases. In the coronavirus 2019 pandemic, multiple RT-PCR-based tests were developed to screen for viral infection. As an emergency response to increasing testing demand, we established a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) PCR diagnostics platform for which we compared different commercial and in-house RT-PCR protocols. Four commercial, one customized, and one in-house RT-PCR protocols were evaluated with 92 SARS-CoV-2-positive and 92 SARS-CoV-2-negative samples. Furthermore, economical and practical characteristics of these protocols were compared. In addition, a highly sensitive digital droplet PCR (ddPCR) method was developed, and application of RT-PCR and ddPCR methods on SARS-CoV-2 environmental samples was examined. Very low limits of detection (1 or 2 viral copies/μL), high sensitivities (93.6% to 97.8%), and high specificities (98.7% to 100%) for the tested RT-PCR protocols were found. Furthermore, the feasibility of downscaling two of the commercial protocols, which could optimize testing capacity, was demonstrated. Tested commercial and customized RT-PCR detection kits show very good and comparable sensitivity and specificity, and the kits could be further optimized for use on SARS-CoV-2 viral samples derived from human and surface swabbed samples

The Importance of Charge in Perturbing the Aromatic Glue Stabilizing the Protein–Protein Interface of Homodimeric tRNA-Guanine Transglycosylase

International audienceBacterial tRNA-guanine transglycosylase (Tgt) is involved in the biosynthesis of the modified tRNA nucleoside queuosine present in the anticodon wobble position of tRNAs specific for aspartate, asparagine, histidine and tyrosine. Inactivation of the tgt gene leads to decreased pathogenicity of Shigella bacteria. Therefore, Tgt constitutes a putative target for Shigellosis drug therapy. Since only active as homodimer, interference with dimer-interface formation may, in addition to active-site inhibition, provide further means to disable this protein. A cluster of four aromatic residues seems important to stabilize the homodimer. We mutated residues of this aromatic cluster and analyzed each exchange with respect to dimer and thermal stability or enzyme activity applying native mass spectrometry, thermal shift assay, enzyme kinetics, and X-ray crystallography. Our structural studies indicate strong influence of pH on homodimer stability. Obviously, protonation of a histidine within the aromatic cluster promotes the collapse of an essential structural motif within the dimer interface at slightly acidic pH

A Transcriptionally Inactive ATF2 Variant Drives Melanomagenesis

Melanoma is one of the most lethal cutaneous malignancies, characterized by chemoresistance and a striking propensity to metastasize. The transcription factor ATF2 elicits oncogenic activities in melanoma, and its inhibition attenuates melanoma development. Here, we show that expression of a transcriptionally inactive form of Atf2 (Atf2Δ8,9) promotes development of melanoma in mouse models. Atf2Δ8,9-driven tumors show enhanced pigmentation, immune infiltration, and metastatic propensity. Similar to mouse Atf2Δ8,9, we have identified a transcriptionally inactive human ATF2 splice variant 5 (ATF2SV5) that enhances the growth and migration capacity of cultured melanoma cells and immortalized melanocytes. ATF2SV5 expression is elevated in human melanoma specimens and is associated with poor prognosis. These findings point to an oncogenic function for ATF2 in melanoma development that appears to be independent of its transcriptional activity