Publications

The accurate spatial segregation into distinct phases within cell membranes coordinates vital biochemical processes and functionalities in living organisms. One of nature's strategies to localize reactivity is the formation of dynamic raft domains. Most raft models rely on liquid-ordered L-0 phases in a liquid-disordered L-d phase lacking correlation and remaining static, often necessitating external agents for phase separation. Here, we introduce a synthetic system of bicomponent glycodendrimersomes coassembled from Janus dendrimers and Janus glycodendrimers (JGDs), where lactose-lactose interactions exclusively drive lateral organization. This mechanism results in modulated phases across two length scales, yielding raft-like microdomains featuring nanoarrays at the nanoscale. By varying the density of lactose and molecular architecture of JGDs, the nanoarray type and size, shape, and spacing of the domains were controlled. Our findings offer insight into the potential primordial origins of rudimentary raft domains and highlight the crucial role of glycans within the glycocalyx.

JTD Keywords: Article, Artificial cells, Atomic force microscopy, Bicomponents, Bilayer, Bilayer membrane, Biochemical functionality, Biochemical process, Biological-membranes, Cell component, Cell membrane, Cellular parameters, Chemical interaction, Chemical structure, Chemistry, Cytology, Defined janus glycodendrimers, Dehydration, Dendrimer, Dendrimers, Dilution, Dimer, External agents, Fourier transform, Giant vesicles, Glycan, Glycans, Glycocalyx, Glycodendrimers, Janus dendrimer, Janus glycodendrimer, Lactose, Lateral organization, Lectin, Lipid rafts, Living organisms, Membrane damage, Membrane microdomain, Membrane microdomains, Membrane structure, Metabolism, Modulated phases, Molecule, Monomer, Nanoarrays, Oligosaccharide, Organization, Periodicity, Phase separation, Phase-separation, Phospholipids, Polysaccharide, Polysaccharides, Raft like domain, Relative humidity, Spatial segregation, Structure analysis, Sugars, Synthetic systems, Tetramer, Unclassified drug, Unilamellar vesicles, Water

Immunoassays show great potential for the detection of low levels of cytokines, due to their high sensitivity and excellent specificity. There is a particular demand for biosensors that enable both high-throughput screening and continuous monitoring of clinically relevant cytokines such as interleukin-6 (IL-6) and tumor necrosis factor-α (TNFα). To this end, we here introduce a novel bioluminescent immunoassay based on the ratiometric plug-and-play immunodiagnostics (RAPPID) platform, with an improved intrinsic signal-to-background and an >80-fold increase in the luminescent signal. The new dRAPPID assay, comprising a dimeric protein G adapter connected via a semiflexible linker, was applied to detect the secretion of IL-6 by breast carcinoma cells upon TNFα stimulation and the production of low concentrations of IL-6 (∼18 pM) in an endotoxin-stimulated human 3D muscle tissue model. Moreover, we integrated the dRAPPID assay in a newly developed microfluidic device for the simultaneous and continuous monitoring of changes in IL-6 and TNFα in the low-nanomolar range. The luminescence-based read-out and the homogeneous nature of the dRAPPID platform allowed for detection with a simple measurement setup, consisting of a digital camera and a light-sealed box. This permits the usage of the continuous dRAPPID monitoring chip at the point of need, without the requirement for complex or expensive detection techniques.

JTD Keywords: cells, code, elisa, il-6, inflammation, kits, pathogenesis, procalcitonin, release, Cytokines, Humans, Immunoassay, Immunologic tests, Interleukin-6, Tumor necrosis factor-alpha

© 2021 Introduction: Natural products of pharmaceutical interest often do not reach the drug market due to the associated low yields and difficult extraction. Knowledge of biosynthetic pathways is a key element in the development of biotechnological strategies for plant specialized metabolite production. The scarce studies regarding non-model plants impair advances in this field. Erythrina spp. are mainly used as central nervous system depressants in folk medicine and are important sources of bioactive tetracyclic benzylisoquinoline alkaloids, which can act on several pathology-related biological targets. Objective: Herein the purpose is to employ combined transcriptome and metabolome analyses (seeds and leaves) of a non-model medicinal Fabaceae species grown in its unique arid natural habitat. The study tries to propose a putative biosynthetic pathway for the bioactive alkaloids by using an omic integrated approach. Methods: The Next Generation Sequencing-based transcriptome (de novo RNA sequencing) was carried out in a Illumina NextSeq 500 platform. Regarding the targeted metabolite profiling, Nuclear Magnetic Resonance and the High-Performance Liquid Chromatography coupled to a micrOTOF-QII, High Resolution Mass Spectrometer, were used. Results: This detailed macro and micromolecular approach applied to seeds and leaves of E. velutina revealed 42 alkaloids by metabolome tools. Based on the combined evidence, 24 gene candidates were put together in a putative pathway leading to the singular alkaloid diversity of this species. Conclusion: These results contribute by indicating potential biotechnological targets Erythrina alkaloids biosynthesis as well as to improve molecular databases with omic data from a non-model medicinal plant. Furthermore, they reveal an interesting chemical diversity in Erythrina velutina harvested in Caatinga. Last, but not least, this data may also contribute to tap Brazilian biodiversity in a rational and sustainable fashion, promoting adequate public policies for preservation and protection of sensitive areas within the Caatinga.

JTD Keywords: benzylisoquinoline alkaloids, caatinga, codeinone reductase, erythrina velutina, expression, mass-spectrometry, molecular-cloning, morphine biosynthesis, natural-products, opium poppy, papaver-somniferum, plant-metabolism, targeted metabolite profile, transcriptome, Benzylisoquinoline alkaloids, Berberine bridge enzyme, Caatinga, Erythrina velutina, Targeted metabolite profile, Transcriptome

JTD Keywords: Optogenetics, Genetically encoded biosensors, Chloride imaging, pH monitoring, Intracellular Ca, Optopharmacology, Photochromic ligands, Photoswitchable tethered ligands

Ler, a member of the H-NS protein family, is the master regulator of the LEE pathogenicity island in virulent Escherichia coli strains. Here, we determined the structure of a complex between the DNA-binding domain of Ler (CT-Ler) and a 15-mer DNA duplex. CT-Ler recognizes a preexisting structural pattern in the DNA minor groove formed by two consecutive regions which are narrower and wider, respectively, compared with standard B-DNA. The compressed region, associated with an AT-tract, is sensed by the side chain of Arg90, whose mutation abolishes the capacity of Ler to bind DNA. The expanded groove allows the approach of the loop in which Arg90 is located. This is the first report of an experimental structure of a DNA complex that includes a protein belonging to the H-NS family. The indirect readout mechanism not only explains the capacity of H-NS and other H-NS family members to modulate the expression of a large number of genes but also the origin of the specificity displayed by Ler. Our results point to a general mechanism by which horizontally acquired genes may be specifically recognized by members of the H-NS family.

JTD Keywords: Enteropathogenic escherichia-coli, Nucleoid-associated protein, Nmr structure determination, Encoded regulator ler, Controls expression, Binding domain