Mucin-like regions, characterized by a local high density of O-linked glycosylation, are found on the viral envelope glycoproteins of many viruses. Herpes simplex virus type 1 (HSV-1), for example, exhibits a mucin-like region on its glycoprotein gC, a viral protein involved in initial recruitment of the virus to the cell surface via interaction with sulfated glycosaminoglycans. So far, this mucin-like region has been proposed to play a key role in modulating the interactions with cellular glycosaminoglycans, and in particular to promote release of HSV-1 virions from infected cells. However, the molecular mechanisms and the role as a pathogenicity factor remains unclear. Using single virus particle tracking, we show that the mobility of chondroitin sulfate-bound HSV-1 virions is decreased in absence of the mucin-like region. This decrease in mobility correlates with an increase in HSV-1-chondroitin sulfate binding forces as observed using atomic force microscopy-based force spectroscopy. Our data suggest that the mucin-like region modulates virus-glycosaminoglycan interactions by regulating the affinity, type, and number of glycoproteins involved in the virus–glycosaminoglycan interaction. This study therefore presents new evidence for a role of the mucin-like region in balancing the interaction of HSV-1 with glycosaminoglycans and provides further insights into the molecular mechanisms used by the virus to ensure both successful cell entry and release from the infected cell.
Viruses are one of the most efficient pathogenic entities on earth, resulting from millions of years of evolution. Each virus particle carries the minimum number of genes and proteins to ensure their reproduction within host cells, hijacking some host replication machinery. However, the role of some viral proteins is not yet unraveled, with some appearing even redundant. For example, murid herpesvirus 4, the current model for human gammaherpesvirus infection, can bind to cell surface glycosaminoglycans using both glycoproteins gp70 and gH/gL. Here, using atomic force microscopy, we discriminate their relative contribution during virus binding to cell surface glycosaminoglycans. Single-virus force spectroscopy experiments demonstrate that gH/gL is the main actor in glycosaminoglycan binding, engaging more numerous and more stable interactions. We also demonstrated that Fab antibody fragments targeting gH/gL or gp70 appear to be a promising treatment to prevent the attachment of virions to cell surfaces.
Information and communication technologies are often considered by policymakers, industrial stakeholders and scientists as a key lever in the run towards sustainability, since they should ease energy efficiency and dematerialization. In this opinion article, nurtured by the inputs of a broad panel of experts, we challenge this widely spread view by highlighting the detrimental social and environmental footprints caused by digital technologies. We further take a critical look on the ways innovation is conducted nowadays, i.e., with an almost exclusive focus on performance and few considerations for externalities. This leads us to call for academic teaching programs advocating for a holistic approach, for new business models, and for ambitious political decisions able to drive a paradigm shift in the mainstream agenda of electronics innovation and digital transition that shall significantly contribute to the well-being of everyone, everywhere, without compromising future generations. We conclude that digital technologies cannot support long-term sustainability if their only purpose remains the optimization of the current system.
Paper substrates are promising for development of cost-effective and efficient point-of-care biosensors, essential for public healthcare and environmental diagnostics in emergency situations. Most paper-based biosensors rely on the natural capillarity of paper to perform qualitative or semi-quantitative colorimetric detections. To achieve quantification and better sensitivity, technologies combining paper-based substrates and electrical detection are being developed. In this work, we demonstrate the potential of electrical measurements by means of a simple, parallel-plate electrode setup towards the detection of whole-cell bacteria captured in nitrocellulose (NC) membranes. Unlike current electrical sensors, which are mostly integrated, this plug and play system has reusable electrodes and enables simple and fast bacterial detection through impedance measurements. The characterized NC membrane was subjected to (i) a biofunctionalization, (ii) different saline solutions modelling real water samples, and (iii) bacterial suspensions of different concentrations. Bacterial detection was achieved in low conductivity buffers through both resistive and capacitive changes in the sensed medium. To capture Bacillus thuringiensis, the model microorganism used in this work, the endolysin cell-wall binding domain (CBD) of Deep-Blue, a bacteriophage targeting this bacterium, was integrated into the membranes as a recognition bio-interface. This experimental proof-of-concept illustrates the electrical detection of 107 colony-forming units (CFU) mL−1 bacteria in low-salinity buffers within 5 min, using a very simple setup. This offers perspectives for affordable pathogen sensors that can easily be reconfigured for different bacteria. Water quality testing is a particularly interesting application since it requires frequent testing, especially in emergency situations.
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