Modular, automated synthesis of spirocyclic tetrahydronaphthyridines from primary alkylamines.

Spirocyclic tetrahydronaphthyridines (THNs) are valuable scaffolds for drug discovery campaigns, but access to this 3D chemical space is hampered by a lack of modular and scalable synthetic methods. We hereby report an automated, continuous flow synthesis of α-alkylated and spirocyclic 1,2,3,4-tetrahydro-1,8-naphthyridines ("1,8-THNs"), in addition to their regioisomeric 1,6-THN analogues, from abundant primary amine feedstocks. An annulative disconnection approach based on photoredox-catalysed hydroaminoalkylation (HAA) of halogenated vinylpyridines is sequenced in combination with intramolecular SNAr N-arylation. To access the remaining 1,7- and 1,5-THN isomers, a photoredox-catalysed HAA step is telescoped with a palladium-catalysed C-N bond formation. Altogether, this provides a highly modular access to four isomeric THN cores from a common set of unprotected primary amine starting materials, using the same bond disconnections. The simplifying power of the methodology is illustrated by a concise synthesis of the spirocyclic THN core of Pfizer's MC4R antagonist PF-07258669.

Controllable Fabrication of Vertical Graphene with Tunable Growth Nature by Remote Plasma-Enhanced Chemical Vapor Deposition.

As an important member of the graphene family, vertical graphene (VG) has broad applications like field emission, energy storage, and sensors owing to its fascinating physical and chemical properties. Among various fabrication methods for VG, plasma enhanced chemical vapor deposition (PECVD) is most employed because of the fast growth rate at relatively low temperature for the high-quality VG. However, to date, relations between growth manner of VG and growth parameters such as growth temperature, dosage of gaseous carbon source, and electric power to generate plasma are still less known, which in turn hinder the massive production of VG for further applications. In this study, the growth behavior of VG was studied as functions of temperature, plasma power, and gas composition (or chamber pressure). It was found that the growth behavior of VG is sensitive to the growth conditions mentioned above. Although conditions with high growth temperature, large flow rate of mixed gas of methane and carrier gases, and high plasma power may be helpful for the fast growth of VG, brunching of VG is simultaneously enhanced, which in turn decreases the vertical growth nature of VG. High-quality VG can be achieved by optimizing the growth parameters. It was revealed that the vertical growth nature of VG is governed by the electric field at the interfacial layer between VG and the substrate, for which its strength is influenced by the density of plasma. These findings are important for the general understanding of the VG growth and provided a feasible way for the controllable fabrication of VG using the remote PECVD method which is usually believed to be unsuitable for the fabrication of VG.

Advances in cis-element- and natural variation-mediated transcriptional regulation and applications in gene editing of major crops.

Transcriptional regulation is crucial to control of gene expression. Both spatio-temporal expression patterns and expression levels of genes are determined by the interaction between cis-acting elements and trans-acting factors. Numerous studies have focused on the trans-acting factors that mediate transcriptional regulatory networks. However, cis-acting elements, such as enhancers, silencers, transposons, and natural variations in the genome, are also vital for gene expression regulation and could be utilized by clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9)-mediated gene editing to improve crop quality and yield. In this review, we discuss current understanding of cis-element-mediated transcriptional regulation in major crops, including rice (Oryza sativa), wheat (Triticum aestivum), and maize (Zea mays), as well as the latest advancements in gene editing techniques and their applications in crops to highlight prospective strategies for crop breeding.

Diversification of three TaSOS1 genes and their roles in sodium exclusion in bread wheat (Triticum aestivum L.).

The ability to exclude sodium from the shoot is a crucial feature of salinity tolerance in bread wheat (Triticum aestivum L.). The plasma membrane sodium/proton exchanger salt-overly-sensitive 1 (SOS1) is a critical Na+. efflux protein in plants. Here, we cloned three homologues of the TaSOS1 gene in bread wheat, designated TaSOS1-A1, TaSOS1-B1 and TaSOS1-D1, respectively, according to the location on group 3 chromosomes 3A, 3B and 3D. Sequence analysis demonstrated that the TaSOS1 deduced protein-contained domains similar to the SOS1 protein, including 12 membrane-spanning regions, a long hydrophilic tail in the C-terminus, the cyclic nucleotidebinding domain, the putative auto-inhibitory domain and the phosphorylation motif. Phylogenetic analysis established the evolutionary relationships between the different copies of this gene in bread wheat and its diploid progenitors, as well as with SOS1 genes from Arabidopsis, rice and Brachypodium distachyon. Analysis of transient TaSOS1-A1::green fluorescent protein expression demonstrated that TaSOS1 was exclusively localized to the plasma membrane. The yeast and Arabidopsis complementary test supported the sodium extrusion function of TaSOS1-A1. Virus-induced gene silencing technology was used to further examine the function of TaSOS1-A1 in bread wheat.

Modulation of MRSA virulence gene expression by the wall teichoic acid enzyme TarO.

Phenol-soluble modulins (PSMs) and Staphylococcal protein A (SpA) are key virulence determinants for community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA), an important human pathogen that causes a wide range of diseases. Here, using chemical and genetic approaches, we show that inhibition of TarO, the first enzyme in the wall teichoic acid (WTA) biosynthetic pathway, decreases the expression of genes encoding PSMs and SpA in the prototypical CA-MRSA strain USA300 LAC. Mechanistically, these effects are linked to the activation of VraRS two-component system that directly represses the expression of accessory gene regulator (agr) locus and spa. The activation of VraRS was due in part to the loss of the functional integrity of penicillin-binding protein 2 (PBP2) in a PBP2a-dependent manner. TarO inhibition can also activate VraRS in a manner independent of PBP2a. We provide multiple lines of evidence that accumulation of lipid-linked peptidoglycan precursors is a trigger for the activation of VraRS. In sum, our results reveal that WTA biosynthesis plays an important role in the regulation of virulence gene expression in CA-MRSA, underlining TarO as an attractive target for anti-virulence therapy. Our data also suggest that acquisition of PBP2a-encoding mecA gene can impart an additional regulatory layer for the modulation of key signaling pathways in S. aureus.

A novel copper-sensing two-component system for inducing Dsb gene expression in bacteria.

In nature, bacteria must sense copper and tightly regulate gene expression to evade copper toxicity. Here, we identify a new copper-responsive two-component system named DsbRS in the important human pathogen Pseudomonas aeruginosa; in this system, DsbS is a sensor histidine kinase, and DsbR, its cognate response regulator, directly induces the transcription of genes involved in protein disulfide bond formation (Dsb) (i.e., the dsbDEG operon and dsbB). In the absence of copper, DsbS acts as a phosphatase toward DsbR, thus blocking the transcription of Dsb genes. In the presence of copper, the metal ion directly binds to the sensor domain of DsbS, and the Cys82 residue plays a critical role in this process. The copper-binding behavior appears to inhibit the phosphatase activity of DsbS, leading to the activation of DsbR. The copper resistance of the dsbRS knock-out mutant is restored by the ectopic expression of the dsbDEG operon, which is a DsbRS major target. Strikingly, cognates of the dsbRS-dsbDEG pair are widely distributed across eubacteria. In addition, a DsbR-binding site, which contains the consensus sequence 5'-TTA-N8-TTAA-3', is detected in the promoter region of dsbDEG homologs in these species. These findings suggest that the regulation of Dsb genes by DsbRS represents a novel mechanism by which bacterial cells cope with copper stress.

Association of Cerebral Small Vessel Disease Burden with Neuropsychiatric Symptoms in Non-Demented Elderly: A Longitudinal Study.

BACKGROUND: The links between cerebral small vessel disease (CSVD) burden and neuropsychiatric symptoms (NPS) have not been fully studied. OBJECTIVE: We aimed to explore the associations of the CSVD burden with Neuropsychiatric Inventory (NPI) total scores and its subsyndromes in the elderly without dementia. METHODS: We investigated 630 non-demented participants from the Alzheimer's Disease Neuroimaging Initiative. All of them had NPI assessments and 3 Tesla MRI scans at baseline and 616 had longitudinal NPI assessments during the follow-up. Linear mixed-effects models were used to investigate the cross-sectional and longitudinal associations of CSVD burden with NPI total scores and its subsyndromes. RESULTS: Higher CSVD burden longitudinally predicted more serious neuropsychiatric symptoms, including NPS (p < 0.0001), hyperactivity (p = 0.0006), affective symptoms (p = 0.0091), and apathy (p < 0.0001) in the total participants. Lacunar infarcts (LIs), white matter hyperactivities (WMHs), and cerebral microbleeds (CMBs) might play important roles in the occurrence of NPS, since they were longitudinally associated with specific neuropsychiatric subsyndromes. LIs contributed to hyperactivity (p = 0.0092), psychosis (p = 0.0402), affective symptoms (p = 0.0156), and apathy (p < 0.0001). WMHs were associated with hyperactivity (p = 0.0377) and apathy (p = 0.0343). However, CMBs were only related to apathy (p = 0.0141). CONCLUSION: CSVD burden was associated with multiple neuropsychiatric symptoms, suggesting the importance of monitoring and controlling vascular risk factors. Different markers of CSVD were associated with specific subsyndromes of NPS, suggesting that different markers tended to occur in different encephalic regions.

The life cycle of Hyalomma scupense (Acari: Ixodidae) under laboratory conditions.

The life cycle of Hyalomma scupense on rabbit hosts was investigated under laboratory conditions. Hy. scupense exhibited one- and two-host life cycles of 163.2 and 161.4 days, respectively. The incubation of eggs required an average period of 52 days, which was the longest period among the four developmental stages. The average time for pre-feeding of larvae was 3.5 days. It took 20 days for larvae to become engorged nymphs and 52.3 days to become engorged females. The duration of the pre-feeding, feeding, pre-oviposition, and oviposition stages of female adults was 2.3, 13.5, 27.5, and 27.9 days, respectively. The average weight of engorged females was 390.0 mg (ranging from 129.3 mg to 828.6 mg), which was 28.95 times the weight of unfed females. There was a positive relationship between the weight and the number of eggs laid by engorged females (r = 0.927). The reproductive efficiency index (REI) was 8.63.

Ratiometric fluorescent sensors for nitrite detection in the environment based on carbon dot/Rhodamine B systems.

A novel carbon dot/Rhodamine B-based ratiometric fluorescent probe was developed for a highly sensitivity and selective detection of nitrite (NO2 -). The probe showed colour changes from blue to orange under ultraviolet light in response to NO2 - with a detection limit as low as 67 nM in the range of 0 to 40 µM. A ratiometric fluorescent test paper was successfully prepared using the probe solution, which demonstrated its feasibility towards a rapid and semi-quantitative detection of NO2 - in real samples.

Novel niclosamide-derived adjuvants elevating the efficacy of polymyxin B against MDR Pseudomonas aeruginosa DK2.

Pseudomonas aeruginosa (P. aeruginosa) DK2 is a multidrug-resistant (MDR) gram-negative bacterial pathogen, being observed serious resistance to the 'last-resort' antibiotic, polymyxin B (PB). Combination therapies with adjuvants have emerged as effective strategies to reactivate the antibiotics resisted by MDR bacteria. Herein, we screened a library of approved drugs and found that niclosamide (NIC), an anthelmintic drug, could potentiate the efficacy of PB against MDR P. aeruginosa DK2. Next, a series of novel NIC-derived adjuvants were designed, synthesized, and evaluated the synergistic activity with PB. Among them, the combination of 15 with PB displayed superior elimination of P. aeruginosa DK2 in vitro and in vivo compared with the single administration. Moreover, this combination decelerated PB-resistance progress in DK2, along with lower potential toxicity. Overall, this study provides a strategy for development antibiotic adjuvants to potentiate PB against MDR P. aeruginosa infections.

The Impact of Sustainable Transformational Leadership on Sustainable Innovation Ambidexterity: Empirical Evidence From Green Building Industries of China.

Recognizing that building work will continually encompass, to a certain degree, unfavorable ecological consequences, green building has been encouraged and advocated as a managerial concept to progress in the construction segment. This research created a conceptual model that analyzed whether sustainable transformational leadership (STL) supported sustainable innovation ambidexterity (SIA) in green building industries. This research model was based on organizational support theory, hope theory, social cognitive theory, and attribution theory. This paper aimed to observe the relationship between STL with SIA via the mediating effect of psychological capital (PC). Furthermore, it examined the impact of perceived organizational support (POS) on PC. Moreover, it further examined the relationship between STL and POS. Likewise, it investigated the mediating effect of PC on the relationship between POS and SIA. Finally, it examined POS as a mediator between the relationship of STL and PC. The data for this study were collected from 600 workers employed at green building businesses in China. A questionnaire was delivered to the workers of green building corporations. According to the findings, STL was discovered to have a positive impact on PC. Furthermore, POS had a significant impact on PC. Moreover, PC significantly influenced SIA. Finally, STL was found to be in a significant relationship with POS. The outcomes of this research are extremely beneficial particularly in the situation of developing economies. This research contributes to the existing knowledge that employees with STL exhibit high PC, POS, and SIA in green building industries.

Ratiometric fluorescence sensor for sensitive detection of inorganic phosphate in environmental samples.

Fast, simple, and low-cost on-site visualized detection of inorganic phosphate (Pi) is in great demand since phosphate is the major reason of eutrophication. In this work, a ratiometric fluorescent probe composed by green carbon dots (GCDs) and red carbon dots (RCDs) has been established for high-sensitivity and selective sensing of Pi. A trend of color change from red to green is observed for the detection of Pi under ultraviolet light and the detection limit is 0.09 µM in the range of 0 to 55 µM. Fluorescent test paper prepared from the probe solution was successfully applied to semi-quantitative visual detection of Pi in real-world water and soil samples, which shows great real-world application potentials.

Genome-Wide Mapping Reveals Complex Regulatory Activities of BfmR in Pseudomonas aeruginosa.

BfmR is a response regulator that modulates diverse pathogenic phenotypes and induces an acute-to-chronic virulence switch in Pseudomonas aeruginosa, an important human pathogen causing serious nosocomial infections. However, the mechanisms of action of BfmR remain largely unknown. Here, using chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq), we showed that 174 chromosomal regions of P. aeruginosa MPAO1 genome were highly enriched by coimmunoprecipitation with a C-terminal Flag-tagged BfmR. Integration of these data with global transcriptome analyses revealed that 172 genes in 106 predicted transcription units are potential targets for BfmR. We determined that BfmR binds to and modulates the promoter activity of genes encoding transcriptional regulators CzcR, ExsA, and PhoB. Intriguingly, BfmR bound to the promoters of a number of genes belong to either CzcR or PhoB regulon, or both, indicating that CzcRS and PhoBR two-component systems (TCSs) deeply feed into the BfmR-mediated regulatory network. In addition, we demonstrated that phoB is required for BfmR to promote the biofilm formation by P. aeruginosa. These results delineate the direct BfmR regulon and exemplify the complexity of BfmR-mediated regulation of cellular functions in P. aeruginosa.

Glucose-Binding of Periplasmic Protein GltB Activates GtrS-GltR Two-Component System in Pseudomonas aeruginosa.

A two-component system GtrS-GltR is required for glucose transport activity in P. aeruginosa and plays a key role during P. aeruginosa-host interactions. However, the mechanism of action of GtrS-GltR has not been definitively established. Here, we show that gltB, which encodes a periplasmic glucose binding protein, is essential for the glucose-induced activation of GtrS-GltR in P. aeruginosa. We determined that GltB is capable of binding to membrane regulatory proteins including GtrS, the sensor kinase of the GtrS-GltR TCS. We observed that alanine substitution of glucose-binding residues abolishes the ability of GltB to promote the activation of GtrS-GltR. Importantly, like the gtrS deletion mutant, gltB deletion mutant showed attenuated virulence in both Drosophila melanogaster and mouse models of infection. In addition, using CHIP-seq experiments, we showed that the promoter of gltB is the major in vivo target of GltR. Collectively, these data suggest that periplasmic binding protein GltB and GtrS-GltR TCS form a complex regulatory circuit that regulates the virulence of P. aeruginosa in response to glucose.

Nogo­66 promotes ß­amyloid protein secretion via NgR/ROCK­dependent BACE1 activation.

The generation of ß­amyloid protein (Aß) is considered a key step in the pathogenesis of Alzheimer's disease (AD) and the regulation of its production is an important therapeutic strategy. It was hypothesized in the present study that Nogo­A may be involved in AD and may regulate the generation of Aß. Nogo­A is known to act as a major inhibitor of neuron regeneration in the adult central nervous system. A recent study indicated that Nogo­A is associated with AD; however, the underlying effect and molecular mechanisms remain largely elusive. In the present study, the potential effects of Nogo­A on AD were investigated. ELISA was used to detect the levels of Aß, enzymatic activity detection kits were used to determine the activity of secretase enzymes in amyloid precursor protein (APP) metabolism, and western blot analysis was used to detect the expression levels of proteins associated with the APP processing and Nogo­A/Nogo­66 receptor (NgR) signaling pathways. The results revealed that Nogo­66, the major inhibitory region of Nogo­A, promoted neuronal Aß secretion by increasing the activity of ß­secretase 1 via the NgR/Rho­associated coiled­coil containing kinases pathway in a dose­dependent manner. The present data suggested that Nogo­A may facilitate the onset and development of AD by promoting Aß secretion, providing information on a potential novel target for AD therapy.

Histamine activates HinK to promote the virulence of Pseudomonas aeruginosa.

During infections, bacteria stimulate host cells to produce and release histamine, which is a key mediator of vital cellular processes in animals. However, the mechanisms underlying the bacterial cell's ability to sense and respond to histamine are poorly understood. Herein, we show that HinK, a LysR-type transcriptional regulator, is required to evoke responses to histamine in Pseudomonas aeruginosa, an important human pathogen. HinK directly binds to and activates the promoter of genes involved in histamine uptake and metabolism, iron acquisition, and Pseudomonas quinolone signal (PQS) biosynthesis. The transcriptional regulatory activity of HinK is induced when histamine is present, and it occurs when HinK binds with imidazole-4-acetic acid (ImAA), a histamine metabolite whose production in P. aeruginosa depends on the HinK-activated histamine uptake and utilization operon hinDAC-pa0222. Importantly, the inactivation of HinK inhibits diverse pathogenic phenotypes of P. aeruginosa. These results suggest that histamine acts as an interkingdom signal and provide insights into the mechanism used by pathogenic bacteria to exploit host regulatory signals to promote virulence.

Mutation-induced remodeling of the BfmRS two-component system in Pseudomonas aeruginosa clinical isolates.

Genetic mutations are a primary driving force behind the adaptive evolution of bacterial pathogens. Multiple clinical isolates of Pseudomonas aeruginosa, an important human pathogen, have naturally evolved one or more missense mutations in bfmS, which encodes the sensor histidine kinase of the BfmRS two-component system (TCS). A mutant BfmS protein containing both the L181P and E376Q substitutions increased the phosphorylation and thus the transcriptional regulatory activity of its cognate downstream response regulator, BfmR. This reduced acute virulence and enhanced biofilm formation, both of which are phenotypic changes associated with a chronic infection state. The increased phosphorylation of BfmR was due, at least in part, to the cross-phosphorylation of BfmR by GtrS, a noncognate sensor kinase. Other spontaneous missense mutations in bfmS, such as A42E/G347D, T242R, and R393H, also caused a similar remodeling of the BfmRS TCS in P. aeruginosa This study highlights the plasticity of TCSs mediated by spontaneous mutations and suggests that mutation-induced activation of BfmRS may contribute to host adaptation by P. aeruginosa during chronic infections.

Alteration of protein homeostasis mediates the interaction of Pseudomonas aeruginosa with Staphylococcus aureus.

Intracellular protein degradation is essential for the survival of all organisms, but its role in interspecies interaction is unknown. Here, we show that the ClpXP protease of Pseudomonas aeruginosa suppresses its antimicrobial activity against Staphylococcus aureus, a common pathogen co-isolated with P. aeruginosa from polymicrobial human infections. Using proteomic, biochemical, and molecular genetic approaches, we found that this effect is due to the inhibitory effects of ClpXP on the quorum sensing (QS) of P. aeruginosa, mainly by degrading proteins (e.g., PhnA, PhnB, PqsR, and RhlI) which are critical for the production of QS signal molecules PQS and C4-HSL. We provide evidence that co-culturing with S. aureus induces a decrease in the activity of ClpXP in P. aeruginosa, an effect which was also achieved by the treatment of P. aeruginosa with N-acetylglucosamine (GlcNAc), a widespread chemical present on the surface of diverse cell types from bacteria to humans. These findings extend the range of biological events governed by proteolytic machinery to microbial community structure, thus also suggesting that a chemical-induced alteration of protein homeostasis is a mechanism for interspecies interactions.

Recent advances in the synthesis and application of copper nanomaterials based on various DNA scaffolds.

Fluorescent copper nanomaterials (CuNMs), including copper nanoparticles (CuNPs) and copper nanoclusters (CuNCs), become more and more popular with the abundant raw materials and low cost. A wide range of applications has been explored due to their fascinating properties such as low toxicity, remarkable water solubility, facile synthesis, large Stokes shifts, and good biocompatibility. As a kind of genetic material, DNA exhibits its molecular recognition function and diversity. The marriage between CuNMs and DNA endows DNA-templated CuNMs (DNA-CuNMs) with unique properties such as fluorescence, electrochemiluminescence and catalytic features. In this review, we summarize the synthesis and recent applications of DNA-CuNMs. Fluorescent CuNMs can be grown on various DNA scaffolds with special sequence design. T base plays an important role in the formation of CuNMs on DNA templates. These fluorescent DNA-CuNMs hold great prospect in logic gate construction, staining and biosensing of DNAs and RNAs, ions, proteins and enzymes, small molecules and so on.

Allelic variation of high molecular weight glutenin subunits of bread wheat in Hebei province of China.

In common wheat (Triticum aestivum L.), allelic variations of Glu-1 loci have important influences on grain end-use quality. The allelic variations in high molecular weight glutenin subunits (HMW-GSs) were identified in 151 hexaploid wheat varieties representing a historical trend in the cultivars introduced or released inHebei province ofChina fromthe years 1970s to 2010s.Thirteen distinct alleles were detected for Glu-1. At Glu-A1, Glu-B1 and Glu-D1, we found that the most frequent alleles were the 1 (43.0%), 7+8 (64.9%), 2+12 (74.8%) alleles, respectively, in wheat varieties. Twenty two different HMW-GS compositions were observed in wheat. Twenty-five (16.6%) genotypes possessed the combination of subunits 1, 7+8, 2+12, 25 (16.6%) genotypes had subunit composition of 2*, 7+8, 2+12; 20 (13.2%) genotypes had subunit composition of null, 7+8, 2+12. The frequency of other subunit composition was less than 10%. The Glu-1 quality score greater than or equal to 9 accounted for 20.6% of the wheat varieties. The percentage of superior subunits (1 or 2* subunit at Glu-A1 locus; 7+8, 14+15 or 17+18 at Glu-B1 locus; 5+10 or 5+12 at Glu-D1 locus) was an upward trend over the last 40 years. The more different superior alleles correlated with good bread-making quality should be introduced for their usage in wheat improvement efforts.