Near-infrared (NIR) fluorescent molecules are of great importance for the visualisation of biological processes. Among the most promising dye scaffolds for this purpose are P&z.dbd;O-substituted ...phospha-xanthene (POX) dyes, which show NIR emission with high photostability. Their practical utility for
in vitro
and
in vivo
imaging has recently been demonstrated. Although classical modification methods have been used to produce POX-based fluorescent probes, it is still a challenge to introduce additional functional groups to control the localisation of the probe in cells. Herein, we report on the development of POXs that bear a 4-ethynylphenyl group on the phosphorus atom. These dyes can subsequently be functionalised with azide-tagged biomolecules
via
a late-stage Cu-catalysed azide/alkyne cycloaddition (CuAAC) reaction, thus achieving target-selective labelling. To demonstrate the practical utility of the functionalised POXs, we designed a sophisticated NIR probe that exhibits a bell-shaped off-on-off pH-response and is able to assess the degree of endosomal maturation.
A series of NIR-emissive phospha-xanthene dyes bearing an ethynyl group are reported. The late-stage functionalisation of the NIR dyes enables creation of multi-functionalised fluorescent probes that can be designed to target organelles of interest.
The multidrug and toxic compound extrusion (MATE) family of proteins consists of transporters responsible for multidrug resistance in prokaryotes. In plants, a number of MATE proteins were identified ...by recent genomic and functional studies, which imply that the proteins have substrate-specific transport functions instead of multidrug extrusion. The three-dimensional structure of eukaryotic MATE proteins, including those of plants, has not been reported, preventing a better understanding of the molecular mechanism of these proteins. Here, we describe the crystal structure of a MATE protein from the plant Camelina sativa at 2.9 Å resolution. Two sets of six transmembrane α helices, assembled pseudo-symmetrically, possess a negatively charged internal pocket with an outward-facing shape. The crystal structure provides insight into the diversity of plant MATE proteins and their substrate recognition and transport through the membrane.
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•Crystal structure of Camelina sativa MATE transporter was described•The internal pocket provides a negatively charged surface for ligand binding•The diversity of plant MATE would bring the substrate recognition specificity
Tanaka et al. represent the crystal structure of a MATE transporter from the plant Camelina sativa. This structure elucidates the long-awaited details of the architecture of the eukaryotic homolog of the bacterial multidrug efflux transporter MATE. The substrate recognition mechanism by the internal pockets is discussed.
A treatment option for constipation that improves the quality of life is needed since available laxatives do not effectively improve the quality of life in patients with constipation. A significant ...association between gut dysbiosis and constipation is recognized, suggesting that probiotics may be an important option for management of constipation. The underlying mechanism by which probiotics improve constipation remains unclear. In this study, we aimed to evaluate the effects of the probiotic Bifidobacterium bifidum G9-1 (BBG9-1) on loperamide-induced delayed colonic transit constipation and to elucidate its mechanism of action. First, the effect of BBG9-1 was evaluated in a rat model of constipation induced by subcutaneous administration of loperamide. BBG9-1 improved constipation parameters (number of feces, fecal water content, and fecal hardness) in constipated rats. Next, the relationship of organic acids and neurotransmitters to gut microbiota was investigated. BBG9-1 improved dysbiosis and prevented a decrease in butyric acid concentration in the gut, increased serum serotonin, and suppressed an increase in dopamine and a decrease in acetylcholine in serum. Further, an increase in the expression level of tryptophan hydroxylase 1, a 5-HT-synthetizing enzyme, was observed. These results suggest that BBG9-1 improves dysbiosis, which results in an increase in organic acids and improvement of neurotransmission. These actions may increase intestinal mobility, finally leading to alleviating constipation. The probiotic BBG9-1 may, therefore, be a potential option for the treatment of constipation.
Serial femtosecond X-ray crystallography (SFX) has revolutionized atomic-resolution structural investigation by expanding applicability to micrometer-sized protein crystals, even at room temperature, ...and by enabling dynamics studies. However, reliable crystal-carrying media for SFX are lacking. Here we introduce a grease-matrix carrier for protein microcrystals and obtain the structures of lysozyme, glucose isomerase, thaumatin and fatty acid-binding protein type 3 under ambient conditions at a resolution of or finer than 2 Å.
The current-electric field ( I-E ) characteristic including high electric fields is a key parameter in the detailed design of power devices such as superconducting rotating machines and ...superconducting current limiters using REBa 2 Cu 3 O y (REBCO, where RE is a rare element) tapes. However, because the REBCO tape may burn out due to heat generation in standard current-carrying measurements, the measurements have been carried out only up to the electric field range of 1 µV/cm, which is the electric field criterion. In this study, the I-E characteristics of REBCO tapes, including high electric fields, were measured using the pulsed current method. Using two different measurement systems with the pulse width ( τ p ) of 10 msec and 2 sec, we have successfully obtained the I-E characteristics of REBCO tape over a wide range of five orders of magnitude than the electric field criterion (1 μV/cm to 100 mV/cm). Furthermore, the I-E property of a composite conductor consisting of REBCO tape and a thick copper plate was estimated by combining the experimental results of the I-E property with that of copper and compared with the experimental results. The results showed good agreement between both. The measurement of I-E characteristics over a wide range of the electric field, including high electric fields, would be useful for predicting the characteristics of composite conductors, evaluating their performance, and designing devices.
In the Japanese hagfish, Eptatretus burgeri, approximately 21% of the genomic DNA in germ cells (2n = 52) consists of 16 chromosomes (eliminated E-chromosomes) that are eliminated from presumptive ...somatic cells (2n = 36). To uncover the eliminated genome (E-genome), we have identified 16 eliminated repetitive DNA families from eight hagfish species, with 11 of these repeats being selectively amplified in the germline genome of E. burgeri. Furthermore, we have demonstrated that six of these sequences, namely EEEb1-6, are exclusively localized on all 16 E-chromosomes. This has led to the hypothesis that the eight pairs of E-chromosomes are derived from one pair of ancestral chromosomes via multiple duplication events over a prolonged evolutionary period. NGS analysis has recently facilitated the re-assembly of two distinct draft genomes of E. burgeri, derived from the testis and liver. This advancement allows for the prediction of not only nonrepetitive eliminated sequences but also over 100 repetitive and eliminated sequences, accomplished through K-mer-based analysis. In this study, we report four novel eliminated repetitive DNA sequences (designated as EEEb7-10) and confirm the relative chromosomal localization of all eliminated repeats (EEEb1-10) by fluorescence in situ hybridization (FISH). With the exception of EEEb10, all sequences were exclusively detected on EEEb1-positive chromosomes. Surprisingly, EEEb10 was detected as an intense signal on EEEb1-positive chromosomes and as a scattered signal on other chromosomes in germ cells. The study further divided the eight pairs of E-chromosomes into six groups based on the signal distribution of each DNA family, and fiber-FISH experiments showed that the EEEb2-10 family was dispersed in the EEEb1-positive extended chromatin fiber. These findings provide new insights into the mechanisms underlying chromosome elimination and the evolution of E-chromosomes, supporting our previous hypothesis.
Recent research has highlighted the importance of the gut microbiome in regulating aging, and probiotics are interventions that can promote gut health. In this study, we surveyed several novel lactic ...acid bacteria to examine their beneficial effect on organismal health and lifespan in C. elegans. We found that animals fed some lactic acid bacteria, including L. acidophilus 1244 and L. paracasei subsp. paracasei 2004, grew healthy. Supplementation with the lactic acid bacterial strains L. acidophilus 1244 or L. paracasei subsp. paracasei 2004 significantly improved health, including food consumption, motility, and resistance to oxidative stressor, hydrogen peroxide. Our RNA-seq analysis showed that supplementation with L. paracasei subsp. paracasei 2004 significantly increased the expression of daf-16, a C. elegans FoxO homolog, as well as genes related to the stress response. Furthermore, daf-16 deletion inhibited the longevity effect of L. paracasei subsp. paracasei 2004 supplementation. Our results suggest that L. paracasei subsp. paracasei 2004 improves health and lifespan in a DAF-16-dependent manner.
With the widespread use of digital pen tablets and touch displays, sketch-based interactive computer-aided design (CAD) user interfaces have attracted considerable attention. In an existing interface ...called the Sketch Input Tracer (SKIT), however, the editing operation performed via an over-sketching stroke can target only a single geometric object at any given time. To overcome this limitation, in this study, we propose a new general-purpose sketch-based interface developed for use in two-dimensional CAD systems. In the proposed interface, a sketch-based editing operation can simultaneously modify the geometry and topology of multiple geometric objects via over-sketching. The interface was developed based on the fuzzy logic-based strategy of SKIT. With this interface, a user can draw in a creative manner; for example, they can begin with a rough sketch and progressively create a detailed design through repeated over-sketches. The results of experiments conducted demonstrate that experts can control the proposed interactive drawing interface and beginners can habituate to controlling it.
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•A new general-purpose sketch-based interface for 2D CAD systems is proposed.•The interface is based on the SKIT fuzzy-logic strategy.•An editing operation via over-sketching can modify multiple geometric objects.•Users can repeatedly over-sketch on a rough drawing to obtain a detailed design.•Adequate controllability by trained users of the interface is shown quantitatively.
Dissolution dynamic nuclear polarization (DNP) has recently gained attention as a method to enhance the sensitivity of liquid NMR spectroscopy and MRI. We demonstrate dissolution of the sample ...hyperpolarized by DNP using photoexcited triplet electrons in 0.38 T at room temperature. The achieved polarization of 0.8% is 6100 times as high as that at thermal equilibrium under the condition. The result is an important step for DNP using photoexcited triplet electrons to become widely used in chemical and biomedical research.
Dicopper complexes of a new p-cresol-2,6-bis(dpa) amide-tether ligand (HL1), Cu2(μ-OH2)(μ-1,3-OAc)(L1)(ClO4)2 (1) and Cu2(μ-1,1-OAc)(μ-1,3-OAc)(L1)X (X = ClO4 (2a), OAc (2b)) were synthesized ...and structurally characterized. 2b rapidly cleaves supercoiled plasmid DNA by activating H2O2 at neutral pH to a linear DNA and shows remarkable cytotoxicity in comparison with related complexes. As 2b is more cytotoxic than HL1, the dicopper core is kept in the cell. A boron dipyrromethene (Bodipy)-modified complex of the p-cresol-2,6-bis(dpa) amide-tether ligand having a Bodipy pendant (HL2), Cu2(μ-OAc)2(L2)(OAc) (3), was synthesized to visualize intracellular behavior, suggesting that 2b attacks the nucleolus and mitochondria. A comet assay clearly shows that 2b does not cleave nuclear DNA. The apoptotic cell death is evidenced from flow cytometry.
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