Construction of BaTiO3-TiO2 hollow sphere heterojunctions for enhanced microwave dynamic therapy in cancer treatment.

Cancer is one of the primary health concerns among humans due to its high incidence rate and lack of effective treatment. Currently, medical techniques to achieve the precise elimination of local cancer lesions with negligible damage to normal tissues are still intensely desired. Herein, we synthesized BaTiO3-TiO2 hollow spheres (BTHSs) for use in microwave dynamic therapy (MWDT) for cancer. Under UV irradiation, BTHSs can mediate the production of multiple reactive oxygen species (ROS), mainly 1O2, which results in a rapid photocatalytic degradation rate (97%), 1.6-fold that of commercial P25. Importantly, the ROS production process can be triggered by microwaves to effectively execute MWDT for cancer. Under microwave irradiation, BTHSs exhibit a remarkable therapeutic effect and slight cytotoxicity. In terms of mechanism, the enhanced ROS production efficiency of BTHSs can be attributed to their unique hollow structure and the formation of a type-II heterojunction by the incorporation of BaTiO3. The hollow structure increases the availability of active sites and enhances light scattering, while the BaTiO3-TiO2 heterojunction enhances the photocatalytic activity of TiO2 through charge transfer and electron-hole separation. Overall, this study provides important insights into the design and optimization of sensitizers for MWDT applications.

Clinical study of left ventricular structure and function in patients with Anderson-Fabry disease before and after enzyme replacement therapy.

AIMS: Cardiac left ventricular hypertrophy (LVH) is the most common manifestation of heart involvement in Anderson-Fabry disease (AFD). Conventional cardiac imaging is not sensitive enough to detect early signs of LVH in AFD. It remains uncertain whether enzyme replacement therapy (ERT) can prevent LVH progression and improve myocardial function. This study aimed to assess the effectiveness of two-dimensional speckle tracking echocardiography (2D-STE) in early detection of cardiac involvement in AFD and monitoring the efficacy of agalsidase alfa and agalsidase beta therapy. METHODS AND RESULTS: Thirteen consecutive AFD patients and 12 healthy controls underwent standard transthoracic 2D, color Doppler, tissue Doppler echocardiography, and 2D strain analysis. Global longitudinal strain (GLS) and global circumferential strain (GCS) were measured. Diastolic strain rate (SR) was extracted. Compared to healthy subjects, AFD patients without LVH showed lower levels of GLS (p < 0.001) and SR (p = 0.01), while there was no difference in GCS (p = 0.82). Following treatment, apical circumferential strain (ACS) showed improvement (p = 0.01). CONCLUSION: In AFD patients without LVH, there was a decrease in global and segmental LS. Higher plasma Lyso-GL-3 concentrations were associated with elevated ACS values after ERT, indicating that ACS in AFD patients without LVH, albeit normal, is involved in early LV dysfunction.

The Arabidopsis thaliana chloroplast division protein FtsZ1 counterbalances FtsZ2 filament stability in vitro.

Bacterial cell and chloroplast division are driven by a contractile "Z ring" composed of the tubulin-like cytoskeletal GTPase FtsZ. Unlike bacterial Z rings, which consist of a single FtsZ, the chloroplast Z ring in plants is composed of two FtsZ proteins, FtsZ1 and FtsZ2. Both are required for chloroplast division in vivo, but their biochemical relationship is poorly understood. We used GTPase assays, light scattering, transmission electron microscopy, and sedimentation assays to investigate the assembly behavior of purified Arabidopsis thaliana (At) FtsZ1 and AtFtsZ2 both individually and together. Both proteins exhibited GTPase activity. AtFtsZ2 assembled relatively quickly, forming protofilament bundles that were exceptionally stable, as indicated by their sustained assembly and slow disassembly. AtFtsZ1 did not form detectable protofilaments on its own. When mixed with AtFtsZ2, AtFtsZ1 reduced the extent and rate of AtFtsZ2 assembly, consistent with its previously demonstrated ability to promote protofilament subunit turnover in living cells. Mixing the two FtsZ proteins did not increase the overall GTPase activity, indicating that the effect of AtFtsZ1 on AtFtsZ2 assembly was not due to a stimulation of GTPase activity. However, the GTPase activity of AtFtsZ1 was required to reduce AtFtsZ2 assembly. Truncated forms of AtFtsZ1 and AtFtsZ2 consisting of only their conserved core regions largely recapitulated the behaviors of the full-length proteins. Our in vitro findings provide evidence that FtsZ1 counterbalances the stability of FtsZ2 filaments in the regulation of chloroplast Z-ring dynamics and suggest that restraining FtsZ2 self-assembly is a critical function of FtsZ1 in chloroplasts.

Homoharringtonine inhibits the progression of hepatocellular carcinoma by suppressing the PI3K/AKT/GSK3ß/Slug signaling pathway.

Homoharringtonine (HHT), was first isolated from the bark of Cephalotaxus harringtonia (Knight ex J. Forbes) K. Koch and Cephalotaxus fortunei Hook trees. The bark extract is used to treat leukemia and in recent years has also been used in traditional Chinese medicine (TCM) to treat solid tumors. However, the inhibitory mechanism of HHT in the progression of hepatocellular carcinoma (HCC) is rarely studied. We aimed to evaluate the antitumor efficacy of HHT on HCC in vitro and in vivo and elucidate the underlying molecular mechanism(s). HCC cell lines, including HCCLM3, HepG2, and Huh7, were used to evaluate the antitumor efficacy of HHT in vitro. Cytotoxicity and proliferative ability were evaluated by MTT and colony formation assays. Cell cycle progression and apoptosis in HHT-treated HCC cells were evaluated by flow cytometry. To determine the migration and invasion abilities of HCC cells, wound-healing and Transwell assays were used. Finally, western blot analysis was used to reveal the proteins involved. We also established a xenograft nude mouse model for in vivo assessments of the preclinical efficacy of HHT, mainly using hematoxylin and eosin staining, immunohistochemistry, ultrasound imaging (USI), and magnetic resonance imaging (MRI). HHT suppressed the proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) of HCC cells, and induced cell cycle arrest at the G2 phase and apoptosis. In the HCC xenograft model, HHT showed an obvious tumor-suppressive effect. Surprisingly, Slug expression was also decreased by HHT via the PI3K/AKT/GSK3ß signaling pathway at least partially suppressed the growth of HCC via the PI3K/AKT/GSK3ß/Slug signaling pathway.

Mapping multivalency in the CLIP-170-EB1 microtubule plus-end complex.

Cytoplasmic linker protein 170 (CLIP-170) is a microtubule plus-end factor that links vesicles to microtubules and recruits the dynein-dynactin complex to microtubule plus ends. CLIP-170 plus-end localization is end binding 1 (EB1)-dependent. CLIP-170 contains two N-terminal cytoskeleton-associated protein glycine-rich (CAP-Gly) domains flanked by serine-rich regions. The CAP-Gly domains are known EB1-binding domains, and the serine-rich regions have also been implicated in CLIP-170's microtubule plus-end localization mechanism. However, the determinants in these serine-rich regions have not been identified. Here we elucidated multiple EB1-binding modules in the CLIP-170 N-terminal region. Using isothermal titration calorimetry and size-exclusion chromatography, we mapped and biophysically characterized these EB1-binding modules, including the two CAP-Gly domains, a bridging SXIP motif, and a unique array of divergent SXIP-like motifs located N-terminally to the first CAP-Gly domain. We found that, unlike the EB1-binding mode of the CAP-Gly domain in the dynactin-associated protein p150Glued, which dually engages the EB1 C-terminal EEY motif as well as the EB homology domain and sterically occludes SXIP motif binding, the CLIP-170 CAP-Gly domains engage only the EEY motif, enabling the flanking SXIP and SXIP-like motifs to bind the EB homology domain. These multivalent EB1-binding modules provided avidity to the CLIP-170-EB1 interaction, likely clarifying why CLIP-170 preferentially binds EB1 rather than the α-tubulin C-terminal EEY motif. Our finding that CLIP-170 has multiple non-CAP-Gly EB1-binding modules may explain why autoinhibition of CLIP-170 GAP-Gly domains does not fully abrogate its microtubule plus-end localization. This work expands our understanding of EB1-binding motifs and their multivalent networks.

Assembly properties of the bacterial tubulin homolog FtsZ from the cyanobacterium Synechocystis sp. PCC 6803.

The tubulin homolog FtsZ is the major cytoskeletal protein in the bacterial cell division machinery, conserved in almost all bacteria, archaea, and chloroplasts. Bacterial FtsZ assembles spontaneously into single protofilaments, sheets, and bundles in vitro, and it also accumulates at the site of division early during cell division, where it forms a dynamic protein complex, the contractile ring or Z-ring. The biochemical properties of FtsZ proteins from many bacteria have been studied, but comparable insights into FtsZs from cyanobacteria are limited. Here, using EM and light-scattering assays, we studied the biochemical and assembly properties of SyFtsZ, the FtsZ protein from the cyanobacterial strain Synechocystis sp. PCC 6803. SyFtsZ had a slow GTPase activity of ∼0.4 GTP/FtsZ molecule/min and assembled into thick, straight protofilament bundles and curved bundles, designated toroids. The assembly of SyFtsZ in the presence of GTP occurred in two stages. The first stage consisted of the assembly of single-stranded straight protofilaments and opened circles; in the second stage, the protofilaments associated into straight protofilament bundles and toroids. In addition to these assemblies, we also observed highly curved oligomers and minirings after GTP hydrolysis or in the presence of excess GDP. The three types of protofilaments of SyFtsZ observed here provide support for the hypothesis that a constriction force due to curved protofilaments bends the membrane. In summary, our findings indicate that, unlike other bacterial FtsZ, SyFtsZ assembles into thick protofilament bundles. This bundling is similar to that of chloroplast FtsZ, consistent with its origin in cyanobacteria.

The cell division protein MinD from Pseudomonas aeruginosa dominates the assembly of the MinC-MinD copolymers.

Cell division of rod-shaped bacteria requires the Z ring, a ring of FtsZ filaments associated with the inner-membrane wall. The MinCDE proteins help localize the Z ring to the center of the Escherichia coli cell. MinC, which inhibits Z-ring assembly, is a passenger on MinD. Previous studies have shown that MinC-MinD from E. coli and Aquifex aeolicus assemble in vitro into extended filaments with a 1:1 stoichiometry. However, a recent study has raised questions about the function of the MinC-MinD copolymer in vivo, because its assembly appears to require a high concentration of these two proteins and has a long lag time, and its blockade does not affect in vivo activities. Here, we found that MinC and MinD from Pseudomonas aeruginosa coassemble into filaments with a 1:1 stoichiometry. We also found that the minimal concentration of ∼4 µm required for assembly applies only to MinD because above 4 µm MinD, even very low MinC concentrations sustained coassembly. As previously reported, the MinC-MinD coassembly exhibited a long lag of ∼100 s when initiated by ATP. Premixing MinD with ATP eliminated this lag, suggesting that it may be due to slow MinD dimerization following ATP activation. We also discovered that MinC-MinD copolymers quickly bound FtsZ filaments and formed huge bundles. Our results resolve previous questions about the low concentration of MinC and the lag time, insights that may inform future investigations into the exact role of the MinC-MinD copolymer in vivo.

Disruption of a Upf1-like helicase-encoding gene OsPLS2 triggers light-dependent premature leaf senescence in rice.

KEY MESSAGE: The OsPLS2 locus was isolated and cloned by map-based cloning that encodes a Upf1-like helicase. Disruption of OsPLS2 accelerated light-dependent leaf senescence in the rice mutant of ospls2. Leaf senescence is a very complex physiological process controlled by both genetic and environmental factors, however its underlying molecular mechanisms remain elusive. In this study, we report a novel Oryza sativa premature leaf senescence mutant (ospls2). Through map-based cloning, a G-to-A substitution was determined at the 1st nucleotide of the 13th intron in the OsPLS2 gene that encodes a Upf1-like helicase. This mutation prompts aberrant splicing of OsPLS2 messenger and consequent disruption of its full-length protein translation, suggesting a negative role of OsPLS2 in regulating leaf senescence. Wild-type rice accordingly displayed a progressive drop of OsPSL2 protein levels with age-dependent leaf senescence. Shading and light filtration studies showed that the ospls2 phenotype, which was characteristic of photo-oxidative stress and reactive oxygen species (ROS) accumulation, was an effect of irritation by light. When continuously exposed to far-red light, exogenous H2O2 and/or abscisic acid (ABA), the ospls2 mutant sustained hypersensitive leaf senescence. In consistence, light and ROS signal pathways in ospls2 were activated by down-regulation of phytochrome genes, and up-regulation of PHYTOCHROME-INTERACTING FACTORS (PIFs) and WRKY genes, all promoting leaf senescence. Together, these data indicated that OsPLS2 played an essential role in leaf senescence and its disruption triggered light-dependent leaf senescence in rice.

The transcription factor Krüppel-like factor 5 promotes cell growth and metastasis via activating PI3K/AKT/Snail signaling in hepatocellular carcinoma.

The transcription factor Krüppel-like factor 5 (KLF5) is highly expressed in many cancers and serves as a prognostic factor. However, the function of KLF5 in hepatocellular carcinoma (HCC) is unclear. In this study, we found that KLF5 was significantly overexpressed in HCC cell lines and specimens, and high KLF5 expression predicted a poor prognosis for HCC patients. Then, we studied the effects of KLF5 on the proliferation, apoptosis, migration and invasion of HCC cells in vitro and vivo. The inhibition of KLF5 markedly inhibited HCC growth and metastasis, while KLF5 overexpression promoted these processes. In addition, we observed that KLF5 could promote the epithelial-mesenchymal transition (EMT) in HCC via the PI3K/AKT/Snail signaling pathway. The silencing of KLF5 in HCC cell lines downregulated the expression of N-cadherin, Vimentin and Snail and increased the expression of the epithelial marker E-cadherin. The expression of MMP2 and MMP9 was also decreased in KLF5-silenced HCC cells. However, opposite results were observed in the KLF5-overexpressing group. These results indicate that KLF5 plays a significant role in HCC progression and metastasis and induces EMT via activating PI3K/AKT/Snail signaling, and the inhibition of KLF5 may be a potential treatment modality for patients with HCC.

The Chloroplast Tubulin Homologs FtsZA and FtsZB from the Red Alga Galdieria sulphuraria Co-assemble into Dynamic Filaments.

FtsZ is a homolog of eukaryotic tubulin and is present in almost all bacteria and many archaea, where it is the major cytoskeletal protein in the Z ring, required for cell division. Unlike some other cell organelles of prokaryotic origin, chloroplasts have retained FtsZ as an essential component of the division machinery. However, chloroplast FtsZs have been challenging to study because they are difficult to express and purify. To this end, we have used a FATT tag expression system to produce as soluble proteins the two chloroplast FtsZs from Galdieria sulphuraria, a thermophilic red alga. GsFtsZA and GsFtsZB assembled individually in the presence of GTP, forming large bundles of protofilaments. GsFtsZA also assembled in the presence of GDP, the first member of the FtsZ/tubulin superfamily to do so. Mixtures of GsFtsZA and GsFtsZB assembled protofilament bundles and hydrolyzed GTP at a rate approximately equal to the sum of their individual rates, suggesting a random co-assembly. GsFtsZA assembly by itself in limiting GTP gave polymers that remained stable for a prolonged time. However, when GsFtsZB was added, the co-polymers disassembled with enhanced kinetics, suggesting that the GsFtsZB regulates and enhances disassembly dynamics. GsFtsZA-mts (where mts is a membrane-targeting amphipathic helix) formed Z ring-like helices when expressed in Escherichia coli Co-expression of GsFtsZB (without an mts) gave co-assembly of both into similar helices. In summary, we provide biochemical evidence that GsFtsZA assembles as the primary scaffold of the chloroplast Z ring and that GsFtsZB co-assembly enhances polymer disassembly and dynamics.

A 22-bp deletion in OsPLS3 gene encoding a DUF266-containing protein is implicated in rice leaf senescence.

Key message The OsPLS3 locus was isolated by map-based cloning that encodes a DUF266-containing protein. OsPLS3 regulates the onset of leaf senescence in rice. Glycosyltransferases (GTs) are one of the most important enzyme groups required for the modification of plant secondary metabolites and play a crucial role in plant growth and development, however the biological functions of most GTs remain elusive. We reported here the identification and characterization of a novel Oryza sativa premature leaf senescence mutant (ospls3). Through map-based cloning strategy, we determined that 22-bp deletion in the OsPLS3 gene encoding a domain of unknown function 266 (DUF266)-containing protein, a member of GT14-like, underlies the premature leaf senescence phenotype in the ospls3 mutant. The OsPLS3 mRNA levels progressively declined with the age-dependent leaf senescence in wild-type rice, implying a negative role of OsPLS3 in regulating leaf senescence. Physiological analysis, and histochemical staining and transmission electron microscopy assays indicated that the ospls3 mutant accumulated higher levels of ethylene and reactive oxygen species than its wild type. Furthermore, the ospls3 mutant showed hypersensitivity to exogenous 1-aminocyclopropane-1-carboxylic acid, H2O2 and high level of cytokinins. Our results indicated that the DUF266-containing gene OsPLS3 plays an important role in the onset of leaf senescence, in part through cytokinin and ethylene signaling in rice.

Oriented Interpenetrating Capillary Network with Surface Engineering by Porous ZnO from Wood for Membrane Emulsification.

Membrane emulsification technology has garnered increasing interest in emulsion preparation due to controllable droplet size, narrower droplet size distribution, low energy consumption, simple process design and excellent reproducibility. Nevertheless, the pore structure and surface engineering in membrane materials design play a crucial role in achieving high-quality emulsions with high throughput simultaneously. In this work, an oriented interpenetrating capillary network composed of highly aligned and interconnected wood cell lumens has been utilized to fabricate an emulsion membrane. A novel honeycomb porous ZnO layer obtained by a seed prefabrication-hydrothermal growth method was designed to reconstruct wood channel surfaces for enhanced microfluid mixing. The results show that through the unique capillary mesh microstructure of wood, the emulsion droplets were smaller in size, had narrower pore-size distribution, and were easy to obtain under high throughput conditions. Meanwhile, a well-designed ZnO layer could further improve the emulsion quality of a wood membrane, while the emulsifying throughput is still maintained at a higher level. This demonstrates that the convection process of the microfluid in these wood capillary channels was intensified markedly. This study not only develops advanced membrane materials in emulsion preparation, but also introduces a brand-new field for functional applications of wood.

Evaluation of microbial communities of Chinese Feng-flavor Daqu with effects of environmental factors using traceability analysis.

Analysis of the changes of microorganisms during Chinese Feng-flavor Daqu fermentation, and the specific contribution of different environmental factors to Daqu microorganisms. High throughput sequencing technology and SourceTracker software were used to analyze the microbial diversity of Feng-flavor Daqu before and after fermentation. 85 fungal and 105 bacterial were detected in the newly pressed Feng-flavor Daqu, while 33 fungal and 50 bacterial in the mature Daqu, and 202 fungal and 555 bacterial in the environmental samples. After fermentation, the microbial community structure of Daqu changed and decreased significantly. 94.7% of fungi come from raw materials and 1.8% from outdoor ground, 60.95% of bacteria come from indoor ground, 20.44% from raw materials, and 8.98% from tools. By comparing the changes of microorganisms in Daqu before and after fermentation, the microorganisms in mature Daqu may mainly come from not only the enhanced strains but also the environment.The source of main microorganisms in Feng-flavor Daqu and the influence of environmental factors on the quality of Daqu were clarified, which provided a basis for improving the quality of Feng-flavor Daqu.

Cyclovirobuxine D inhibits growth and progression of non­small cell lung cancer cells by suppressing the KIF11­CDC25C­CDK1­CyclinB1 G2/M phase transition regulatory network and the NFκB/JNK signaling pathway.

Lung cancer is the leading cause of cancer­related mortality worldwide. Non­small cell lung cancer (NSCLC) is the most common pathological subtype of lung cancer and is associated with low 5­year overall survival rates. Therefore, novel and effective chemotherapeutic drugs are urgently required for improving the survival outcomes of patients with lung cancer. Cyclovirobuxine D (CVB­D) is a natural steroidal alkaloid, used for the treatment of cardiovascular diseases in Traditional Chinese Medicine. Several studies have also demonstrated the antitumor effects of CVB­D. Therefore, in the present study, the therapeutic effects of CVB­D in lung cancer and the underlying mechanisms were investigated using the in vivo xenograft model of NSCLC in nude mice and in vitro experiments with the NSCLC cell lines. Bioinformatics analyses of RNA­sequencing data, and cell­based functional assays demonstrated that CVB­D treatment significantly inhibited in vitro and in vivo NSCLC cell proliferation, survival, invasion, migration, angiogenesis, epithelial­to­mesenchymal transition and G2/M phase cell cycle. CVB­D exerted its antitumor effects by inhibiting the KIF11­CDK1­CDC25C­cyclinB1 G2/M phase transition regulatory oncogenic network and the NF­κB/JNK signaling pathway. CVB­D treatment significantly reduced the sizes and weights and malignancy of xenograft NSCLC tumors in the nude mice. In conclusion, the present study demonstrated that CVB­D inhibited the growth and progression of NSCLC cells by inhibiting the KIF11­CDK1­CDC25C­CyclinB1 G2/M phase transition regulatory network and the NF­κB/JNK signaling pathway. Therefore, CVB­D is a promising drug for the treatment of NSCLC patients.

The C-terminal domain of MinC, a cell division regulation protein, is sufficient to form a copolymer with MinD.

Assembly of cell division protein FtsZ into the Z-ring at the division site is a key step in bacterial cell division. The Min proteins can restrict the Z-ring to the middle of the cell. MinC is the main protein that obstructs Z-ring formation by inhibiting FtsZ assembly. Its N-terminal domain (MinCN ) regulates the localization of the Z-ring by inhibiting FtsZ polymerization, while its C-terminal domain (MinCC ) binds to MinD as well as to FtsZ. Previous studies have shown that MinC and MinD form copolymers in vitro. This copolymer may greatly enhance the binding of MinC to FtsZ, and/or prevent FtsZ filaments from diffusing to the ends of the cell. Here, we investigated the assembly properties of MinCC -MinD of Pseudomonas aeruginosa. We found that MinCC is sufficient to form the copolymers. Although MinCC -MinD assembles into larger bundles, most likely because MinCC is spatially more readily bound to MinD, its copolymerization has similar dynamic properties: the concentration of MinD dominates their copolymerization. The critical concentration of MinD is around 3 µm and when MinD concentration is high enough, a low concentration MinCC could still be copolymerized. We also found that MinCC -MinD can still rapidly bind to FtsZ protofilaments, providing direct evidence that MinCC also interacts directly with FtsZ. However, although the presence of minCC can slightly improve the division defect of minC-knockout strains and shorten the cell length from an average of 12.2 ± 6.7 to 6.6 ± 3.6 µm, it is still insufficient for the normal growth and division of bacteria.

Polydatin protects against calcium oxalate crystal-induced renal injury through the cytoplasmic/mitochondrial reactive oxygen species-NLRP3 inflammasome pathway.

BACKGROUND: Oxidative stress and inflammatory responses are critical factors in calcium oxalate (CaOx) crystal-induced renal injury. Reactive oxygen species (ROS) are usually produced in the cytoplasm and mitochondria and trigger the priming and activation of the NLRP3 inflammasome, thereby regulating cytokines and inflammation. Polydatin is a plant rhizome extract with anti-inflammatory, antioxidant, and antitumor effects. However, it remains not clear whether and how these pathophysiological processes exists in CaOx crystal-induced renal inflammatory injury. METHODS: Here, we measured the expression of the NLRP3 inflammasome, IL-18, IL-1ß, intracellular and mitochondrial ROS (mtROS) levels and relevant morphological changes in treated renal tubular epithelial cells (TECs) and stone-forming rats. The study further explored the action of intracellular ROS and mtROS on these inflammatory damage, and the beneficial effects and pathway of polydatin. RESULTS: We verified that CaOx crystal-induced cytoplasmic ROS and mtROS upregulation promoted the priming and activation of the NLRP3 inflammasome, thereby stimulating IL-18/1ß maturation and activation. Polydatin can relieve oxidative stress and inflammatory damage by decreasing ROS. We further demonstrated that mtROS is the main target for polydatin to exert the NLRP3 inflammasome-regulating function. The inhibition of mtROS can effectively relieve the inflammatory damage to TECs and kidney caused by CaOx crystal. CONCLUSION: These findings provide new insight into the relationship between mitochondrial damage and inflammation in nephrolithiasis and show that polydatin-mediated anti-inflammatory and antioxidative protection is a therapeutic strategy for, but not limited to, crystalline nephropathy.

SulA inhibits assembly of FtsZ by a simple sequestration mechanism.

We have investigated the inhibition by SulA of the assembly of Escherichia coli FtsZ. Using quantitative GTPase and fluorescence assays, we found that SulA inhibition resulted in an increase in the apparent critical concentration for FtsZ assembly. The increase in apparent critical concentration was always less than the total amount of SulA added, suggesting that the association of SulA and FtsZ was of modest affinity. Isothermal titration calorimetry gave a value of 0.78 µM for the dissociation constant of the FtsZ-SulA complex, similar in magnitude to the 0.72 µM critical concentration of FtsZ protofilament assembly at steady state. We modeled the reaction as an equilibrium competition between (a) FtsZ subunits assembling onto protofilaments or (b) binding SulA. When FtsZ was assembled in GMPCPP or in EDTA, the inhibition by SulA was reduced. The reduced inhibition could be explained by a 3- and 10-fold weaker binding of SulA to FtsZ. The mutant D212G, which has no GTPase activity and therefore minimal subunit cycling, was shown here to assemble one-stranded protofilaments, and the assembly was blocked by SulA. We also assayed the SulA and FtsZ proteins from Pseudomonas. The SulA inhibition was stronger than with the E. coli proteins, and the model indicated a 5-fold higher affinity of Pseudomonas SulA for FtsZ.

The impact of different AR-HUD virtual warning interfaces on the takeover performance and visual characteristics of autonomous vehicles.

OBJECTIVE: The objective of this study was to determine the different effects of the arrow-pointing augmented reality head-up display (AR-HUD) interface, virtual shadow AR-HUD interface, and non-AR-HUD interface on autonomous vehicle takeover efficiency and driver eye movement characteristics in different driving scenarios. METHODS: Thirty-six participants were selected to carry out a simulated driving experiment, and the eye movement index and takeover time were analyzed. RESULTS: The arrow pointing AR-HUD interface and the virtual shadow AR-HUD interface could effectively reduce the driver's visual distraction, improve the efficiency of obtaining visual information, reduce the number of times the driver's eyes leave the road, and improve the efficiency of the takeover compared with the non-AR-HUD interface, but there was no significant difference in eye movement indexes between the arrow pointing AR-HUD interface and the more eye-catching virtual shadow AR-HUD interface. When specific scenarios were considered, it was found that in the scenario of emergency braking of the vehicle in front, the arrow pointing AR-HUD interface and the virtual shadow AR-HUD interface had more advantages in takeover efficiency than the non-AR-HUD interface. However, in the scenarios of a rear vehicle overtaking the vehicle ahead and non-motor vehicles running red lights, there was no significant difference in takeover efficiency. For the non-motor vehicle invading the line, emergency U-turn of the vehicle in front, and pedestrian crossing scenarios, the virtual shadow AR-HUD interface had the highest takeover efficiency. CONCLUSIONS: These research results can help improve the active safety of autonomous vehicle AR-HUD interfaces.

How Do MinC-D Copolymers Act on Z-Ring Localization Regulation? A New Model of Bacillus subtilis Min System.

Division site selection in rod-shaped bacteria is strictly regulated spatially by the Min system. Although many sophisticated studies, including in vitro recombination, have tried to explain these regulations, the precise mechanisms are still unclear. A previous model suggested that the concentration gradient of MinC, an FtsZ inhibitor, regulates the position of the Z-ring in the cell. In Escherichia coli, the oscillation of MinCDE proteins leads to a gradient of Min proteins with the average concentration being lowest in the middle and highest near the poles. In contrast to the Min system of E. coli, the Min system of Bacillus subtilis lacks MinE and exhibits a stable concentration distribution, which is regulated by the binding of DivIVA to the negative curvature membrane. The Min proteins first accumulate at the poles of the cell and relocalize near the division site when the membrane invagination begins. It is inconsistent with the previous model of high concentrations of MinC inhibiting Z-ring formation. Our preliminary data here using electron microscopy and light scattering technology reported that B. subtilis MinC (BsMinC) and MinD (BsMinD) also assembled into large straight copolymers in the presence of ATP, similar to the Min proteins of E. coli. Their assembly is fast and dominated by MinD concentration. When BsMinD is 5 µM, a clear light scattering signal can be observed even at 0.3 µM BsMinC. Here, we propose a new model based on the MinC-D copolymers. In our hypothesis, it is not the concentration gradient of MinC, but the MinC-D copolymer assembled in the region of high concentration MinD that plays a key role in the regulation of Z-ring positioning. In B. subtilis, the regions with high MinD concentration are initially at both ends of the cell and then appear at midcell when cell division began. MinC-D copolymer will polymerize and form a complex with MinJ and DivIVA. These complexes capture FtsZ protofilaments to prevent their diffusion away from the midcell and narrow the Z-ring in the middle of the cell.

Quantifying the Elasticity Properties of the Median Nerve during the Upper Limb Neurodynamic Test 1.

Background: The upper limb neurodynamic test 1 (ULNT1) consists of a series of movements that are thought to detect an increase in neuromechanical sensitivity. In vivo, no trail was made to quantify the association between the nerve elasticity and different limb postures during ULNT1. Objectives: (1) To investigate the relationship between nerve elasticity and limb postures during ULNT1 and (2) to investigate the intra- and interoperator reliabilities of shear wave elastography (SWE) in quantifying the elasticity of median nerve. Methods: Twenty healthy subjects (mean age: 19.9 ± 1.4 years old) participated in this study. The median nerve was imaged during elbow extension in the following postures: (1) with neutral posture, (2) with wrist extension (WE), (3) with contralateral cervical flexion (CCF), and (4) with both WE and CCF. The intra- and interoperator reliabilities measured by two operators at NP and CCF+WE and intraclass correlation coefficients (ICCs) were calculated. Results: The intraoperator (ICC = 0.72-0.75) and interoperator (ICC = 0.89-0.94) reliabilities for measuring the elasticity of the median nerve ranged from good to excellent. The mean shear modulus of the median nerve increased by 53.68% from NP to WE+CCF. Conclusion: SWE is a reliable tool to quantify the elasticity of the median nerve. There was acute modulation in the elasticity of the median nerve during the ULNT1 when healthy participants reported substantial discomfort. Further studies need to focus on the elasticity properties of the median nerve in patients with peripheral neuropathic pain.