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Autophagy plays a critical role in many vitally important physiological and pathological processes, such as the removal of damaged and aged organelles and redundant proteins. Although autophagy is mainly a protective process for cells, it can also cause cell death. In this study, we employed in situ and ex situ surface-enhanced Raman scattering (SERS) spectroscopies to obtain chemical information of lysosomes of HepG2 cells. Results reveal that the SERS profiles of the isolated lysosomes are different from the in situ spectra, indicating that lysosomes lie in different microenvironments in these two cases. We further investigated the molecular changes of isolated lysosomes according to the autophagy induced by starvation viaex situ SERS. During autophagy, the conformation of proteins and the structures of lipids have been affected, and autophagy-related molecular evidence is given for the first time in the living lysosomes. We expect that this study will provide a reference for understanding the cell autophagy mechanism.

This study evaluated the effect of incorporating phosphorylated chitosan/amorphous calcium phosphate nanocomplex (Pchi/ACP) into an experimental light-cure composite resin on mechanical-chemical properties and human dentin remineralization. The results showed that the mechanical strength and contact angles of the resins decreased with the increase incorporation of Pchi/ACP. Release concentrations of calcium in saline solution were measured at different time points, showing the incorporation of Pchi/ACP significantly increased calcium release within 14 days, and kept steady thereafter. Finally, the demineralized dentin slabs treated with our resins for four weeks were characterized by SEM-EDS. Various amounts of apatite were formed on the dentin slabs which were treated with the resins containing Pchi/ACP, whereas no apatite was formed without Pchi/ACP. In conclusion, the Pchi/ACP-incorporating composite resin can be a promising dental material due to its favorable mechanical and remineralization properties.

Polymer thin film memristors based on the egg-white dielectric are achieved through a simple solution process, showing the coexistence of the clockwise and counterclockwise current hysteresis in a single device. Such unique memristive feature originates from two competing effects in the egg-white dielectric that possess different effective time ranges. The ion redistribution and charge trapping effects are dominant over relatively short and long timescales, respectively. The reversible and timescale dependent memristive characteristics in the polymer memristors may offer a new strategy towards organic electronic synapses.

Organelles are involved in many cell life activities, and their metabolic or functional disorders are closely related to apoptosis, neurodegenerative diseases, cardiovascular diseases, and the development and metastasis of cancers. The explorations of subcellular structures, microenvironments, and their abnormal conditions are conducive to a deeper understanding of many pathological mechanisms, which are expected to achieve the early diagnosis and the effective therapy of diseases. Organelles are also the targeted locations of drugs, and they play significant roles in many targeting therapeutic strategies. Surface-enhanced Raman spectroscopy (SERS) is a powerful analytical tool that can provide the molecular fingerprint information of subcellular compartments and the real-time cellular dynamics in a non-invasive and non-destructive way. This review aims to summarize the recent advances of SERS studies on subcellular compartments, including five parts. The introductions of SERS and subcellular compartments are given. SERS is promising in subcellular compartment studies due to its molecular specificity and high sensitivity, and both of which highly match the high demands of cellular/subcellular investigations. Intracellular SERS is mainly cataloged as the labeling and label-free methods. For subcellular targeted detections and therapies, how to internalize plasmonic nanoparticles or nanostructure in the target locations is a key point. The subcellular compartment SERS detections, SERS measurements of isolated organelles, investigations of therapeutic mechanisms from subcellular compartments and microenvironments, and integration of SERS diagnosis and treatment are sequentially presented. A perspective view of the subcellular SERS studies is discussed from six aspects. This review provides a comprehensive overview of SERS applications in subcellular compartment researches, which will be a useful reference for designing the SERS-involved therapeutic systems.

RNA silencing is a conserved mechanism in eukaryotic organisms to regulate gene expression. Argonaute (AGO), Dicer-like (DCL) and RNA-dependent RNA polymerase (RDR) proteins are critical components of RNA silencing, but how these gene families’ functions in sugarcane were largely unknown. Most stress-resistance genes in modern sugarcane cultivars (Saccharum spp.) were originated from wild species of Saccharum, for example S. spontaneum. Here, we used genome-wide analysis and a phylogenetic approach to identify four DCL, 21 AGO and 11 RDR genes in the S. spontaneum genome (termed SsDCL, SsAGO and SsRDR, respectively). Several genes, particularly some of the SsAGOs, appeared to have undergone tandem or segmental duplications events. RNA-sequencing data revealed that four SsAGO genes (SsAGO18c, SsAGO18b, SsAGO10e and SsAGO6b) and three SsRDR genes (SsRDR2b, SsRDR2d and SsRDR3) tended to have preferential expression in stem tissue, while SsRDR5 was preferentially expressed in leaves. qRT-PCR analysis showed that SsAGO10c, SsDCL2 and SsRDR6b expressions were strongly upregulated, whereas that of SsAGO18b, SsRDR1a, SsRDR2b/2d and SsRDR5 was significantly depressed in S. spontaneum plants exposed to PEG-induced dehydration stress or infected with Xanthomonas albilineans, causal agent of leaf scald disease of sugarcane, suggesting that these genes play important roles in responses of S. spontaneum to biotic and abiotic stresses.

Mitochondrion is one of the most important organelles and becomes a target in many cancer therapeutic strategies. Mitochondrial microenvironments in response to therapeutic methods are the key to understand therapeutic mechanisms. However, they are almost rarely studied. Herein, the mitochondrial microenvironments, including mitochondrial membrane potential (MMP) and reactive oxygen species (ROS) after different photodynamic therapy (PDT) dosages, were monitored by fluorescent imaging and compared among three cell lines (HepG2, MCF-7, and LO2). Furthermore, the fluctuations of intramitochondrial pHs were revealed via a plasmonic mitochondrion-targeting surface-enhanced Raman scattering (SERS) pH nanosensor. Results indicate that the MMP decreases gradually with the ROS generation and the cancerous cells exhibit less response to excess ROS relative to normal cells. On the other hand, the pH value in the mitochondria decreases initially and then increases when the amount of ROS increases. The LO2 cell is preliminarily evidenced to have a higher self-adjustment ability due to its better tolerance to differential intra/extracellular pHs. This study may provide a basis for an in-depth understanding of the mechanisms of the mitochondrial targeting-based PDT therapeutic processes. It is also helpful for more accurate and useful diagnosis according to intramitochondrial microenvironments and improvement on therapy efficiency of cancers.

The direct use of ammonium hydroxide in amination for the synthesis of primary amines is considered to be one of the major challenges in synthetic organic chemistry. Herein, the first example of catalyst-free direct amination of 3-halooxindoles with ammonium hydroxide to synthesize N-unprotected 3-tetrasubstituted aminooxindoles in high yields (up to 91% yield) is described. An enhancement of the reaction rate on using water was observed under mild conditions. Such an approach is not only protection/deprotection-free, but also more practical and cost-effective. Moreover, this method could expand the library of 3-tetrasubstituted aminooxindole building blocks for the further synthesis of AG-041R, GHSR antagonists and a charteline unit, opening up a new synthetic pathway in the chemistry of 3-aminooxindoles.

Carbon dots (CDs) have been widely used in biological research including bioimaging, biosensing, and biomedicine because of their excellent biocompatibility. However, inefficient absorption of these CDs in the visible-to-near-infrared window limits their applications for photo-sensitive cancer therapeutic strategies and in vivo imaging. Herein, novel supra-carbon dots (SCDs, approximately 20 nm) with high visible-NIR absorption, large photothermal efficiency, and specific cancer cell and mitochondria-targeting feature were prepared by the self-assembly of small-sized CDs (approximately 5 nm) under an acidic environment, followed by modification of cancer cell- and mitochondria-targeting peptides. These targeting SCDs were applied for precisely damaging cancer cells by an NIR photothermal therapy (PTT), and the viability rate difference between the cancer and normal cells is as large as 70%, indicating high specificity and high selectivity. In addition, the destruction of mitochondria was observed by confocal fluorescence microscopy, and the real-time dynamics of the cellular molecules during this process were further evaluated by surface-enhanced Raman spectroscopy. The results reveal that the produced hyperthermia may first incite structural changes in lipid, protein, and deoxyribonucleic acid and then induce cell death. Our results are helpful for the preparation of new CDs-based photothermal materials and the development of more efficient photothermal therapeutic platforms.

To date, although there are many studies investigating the toxicity of heavy metal to plant, little research exists in the seasonal freeze-thaw (FT) regions where FT cycles often happen during the plant growing process. To reveal the adaptive mechanisms of plants to the combination stresses of cadmium (Cd) and FT, the Cd accumulation, subcellular distribution, chemical forms, and antioxidant enzyme activity (peroxidase (POD)) were investigated in spinach (Spinacia oleracea L.) growing under different soil Cd levels (i.e., 0.10 mg Cd kg−1 soil (low), 1.21 mg Cd kg−1 soil (medium), and 2.57 mg Cd kg−1 soil (high)). Compared to the non-freeze-thaw (NFT) treatments, higher Cd concentrations in the root and lower translocation factors from root to leaf were found for the plants experiencing FT cycles. FT significantly decreased the Cd concentrations in the leaves under the low- and medium-Cd treatments, while similar values were found for the high-Cd treatments. Generally, FT could decrease the concentrations and proportions of Cd stored in the cell wall and soluble fractions and increase them in the organelle fractions for the medium- and high-Cd treatments, while opposite tendency was found for the low-Cd treatments. Moreover, larger Cd amounts in the inorganic and water-soluble forms were found for the low- and medium-Cd treated plants under FT, while lower values were found for the high-Cd treatments. Additionally, POD, which presented higher activities at the low- and medium-Cd treatments and lower activities at the high-Cd treatments under FT, were also significantly influenced by the Cd × FT interaction. This study indicated that FT could significantly change the accumulations of Cd in plant, and it provided a new insight into the Cd accumulation by plants in the seasonal FT region.

The biosynthetic genes for secondary metabolites are often clustered into giant operons with no transcription terminator before the end. The long transcripts are frangible and the transcription efficiency declines along with the process. Internal promoters might occur in operons to coordinate the transcription of individual genes, but their effects on the transcription of operon genes and the yield of metabolites have been less investigated. Epothilones are a kind of antitumor polyketides synthesized by seven multifunctional enzymes encoded by a 56-kb operon. In this study, we identified multiple internal promoters in the epothilone operon. We performed CRISPR-dCas9–mediated transcription activation of internal promoters, combined activation of different promoters, and activation in different epothilone-producing M. xanthus strains. We found that activation of internal promoters in the operon was able to promote the gene transcription, but the activation efficiency was distinct from the activation of separate promoters. The transcription of genes in the operon was influenced by not only the starting promoter but also internal promoters of the operon; internal promoters affected the transcription of the following and neighboring upstream/downstream genes. Multiple interferences between internal promoters thus changed the transcriptional profile of operon genes and the production of epothilones. Better activation efficiency for the gene transcription and the epothilone production was obtained in the low epothilone-producing strains. Our results highlight that interactions between promoters in the operon are critical for the gene transcription and the metabolite production efficiency.

BackgroundChronic cough is a common complaint which affects a large number of patients worldwide. Increased cough sensitivity is a very important cause of chronic persistent cough. However, there are limited clinical diagnosis and treatment for increased cough sensitivity. Transient receptor potential vanilloid-1 (TRPVl) is a member of the transient receptor potential (TRP) family of channels which is very closely associated with respiratory diseases. However, the mechanism through which TRPV1 that influences downstream events is still poorly understood.ResultsCapsaicin induced increase in cough sensitivity by upregulating the protein level of TRPV1, leading to the secretions of Substance P and neurokinin A which stimulated neurogenic inflammation. However, sinomenine, a component of traditional Chinese medicine, significantly attenuated the capsaicin-induced cough by inhibiting the expression of TRPV1 in guinea pigs. In addition, capsaicin increased the expression of SOX5 which mediated the transcriptional upregulation of TRPV1. However, pretreatment with sinomenine reduced the expression of SOX5.ConclusionThese results indicate that capsaicin induced increase in cough sensitivity by activating neurogenic inflammation, while sinomenine attenuated the increase in cough sensitivity by inhibiting the expressions of SOX5 and TRPV1 in guinea pigs. This finding may provide a novel target for the treatment of aggravated cough sensitivity.

PbS colloidal quantum dots passivated by the thiocyanate anion (SCN–) are developed to combine with perovskite (CH3NH3PbI3) as building blocks for UV–vis–NIR broadband photodetectors. Both high ele...

A new method was developed for the facile one-pot multicomponent construction of heterocycle-fused spiro compounds containing chromanone and pyrrolidinyl spirooxindoles, two potential pharmacophore...

Summary Glycosylation of natural products can influence their pharmacological properties, and efficient glycosyltransferases (GTs) are critical for this purpose. The polyketide epothilones are potent anti‐tumour compounds, and YjiC is the only reported GT for the glycosylation of epothilone. In this study, we phylogenetically analysed 8261 GTs deposited in CAZy database and revealed that YjiC locates in a subbranch of the Macrolide I group, forming the YjiC‐subbranch with 160 GT sequences. We demonstrated that the YjiC‐subbranch GTs are normally efficient in epothilone glycosylation, but some showed low glycosylation activities. Sequence alignment of YjiC‐subbranch showed that the 66th and 77th amino acid residues, which were close to the catalytic cavity in molecular docking model, were conserved in five high‐active GTs (Q66 and P77) but changed in two low‐efficient GTs. Site‐directed residues swapping at the two positions in the two low‐active GTs (BssGT and BamGT) and the high‐active GT BsGT‐1 demonstrated that the two amino acid residues played an important role in the catalytic efficiency of epothilone glycosylation. This study highlights that the potent GTs for appointed compounds are phylogenetically grouped with conserved residues for the catalytic efficiency.

Highly reliable detection, imaging, and monitoring of reactive oxygen species (ROS) at subcellular organelles are critical for understanding the biological roles of ROS and learning the pathogenesis of some diseases. In this study, we presented an interference-free surface-enhanced Raman scattering (SERS)-active nanoprobe for the intracellular ROS detection. This nanoprobe was designed as an Au core-Ag shell nanoparticle (Au@Ag NPs) with a SERS reporter (4-mercaptobenzonitrile) resided in the inner of the core-shell. Intracellular ROS is able to etch the Ag shell and dramatically decreases the SERS intensity of the SERS reporters. It is worth mentioning that the Raman band of the reporter we used in this study locate in the cellular Raman-silent region (1800–2800 cm−1), which eliminates interference possibility from cellular molecules. The shell can also further protect the reporters from the interference of mediums. We detected ROS at subcellular organelle level, e.g. mitochondria, by modifying the surface of the nanoprobes with a mitochondria-targeting peptide. And for the first time, the SERS-based monitoring of ROS at mitochondria during the photothermal therapy process was validated and the profiles of the ROS distribution were disclosed by SERS mapping.

A series of (R)-2-phenyl-4,5-dihydrothiazole-4-carboxamide derivatives containing a sulfur ether moiety were synthesized and characterized on the basis of NMR and elemental analysis (EA). The crystal structure of (R)-N-(2-methyl-1-(methylthio)propan-2-yl)-2-(4-nitrophenyl)-4,5-dihydrothiazole-4-carboxamide (13d) was determined to show R configuration. The bioasssy results indicated that most title compounds displayed good and broad spectrum antifungal activities against several phytopathogenic fungi. The structure activity relationships were discussed. Based on the antifungal activity of title compounds against Phytophthora capsici, a CoMSIA calculation was performed to establish a 3D-QSAR model, which revealed that electrostatic and hydrophobic fields were the two most significant factors for antifungal activity. According to the established 3D-QSAR model, structure optimization was carried out to find (R)-N-((R)-1-(methylthio)propan-2-yl)-2-(p-tolyl)-4,5-dihydrothiazole-4-carboxamide (15h) with excellent activity against Phytophthora capsici, thus emerging as a new lead compound for novel antiphytopathogenic fungus agent development.

A new methodology was developed for the highly efficient one-pot multicomponent synthesis of chromanone-based 3,3′-pyrrolidinyl-spirooxindoles via a 1,3-dipolar cycloaddition reaction of chromones 1 with azomethine ylides (thermally generated in situ from isatins and proline or thioproline). Another valuable application of this method was for the less reactive chromone through a carboxylic acid-activation and then decarboxylation strategy, which enabled diversity-oriented synthesis of complex pirooxindoles bearing four contiguous stereocenters (one of which is a spiro quaternary stereocenter) with high efficiency and stereoselectivity (up to 90% yield and 20:1 d.r.). This protocol could provide libraries of stereochemically rich and multiple pharmecore collections, that will help in search for new drug-like molecules.

Background: Finding out more predictors of drug-resistant tuberculosis (DR-TB) helps to facilitate TB prevention and control. Previous study had revealed that tobacco smoking and alcohol drinking might be a risk factor for developing drug-resistant tuberculosis. However, few discussed their joint impact on resistance among newly diagnosed TB cases. This study aimed to assess and compare the joint and independent effect of smoking and drinking on TB resistance.Methods: This was a retrospective study of 7996 newly diagnosed TB patients who were collected from Shandong, China from Jan 1, 2004, to Dec 31, 2020, and all had drug susceptibility results, information about smoking and alcohol consumption. Patients were classified into four groups including smoker only(G1), drinker only(G2), smoker+drinker(G3), non-smoker+non-drinker group(G0). We described the drug-resistant profiles, clinical factors and also calculated the ORs of different drug-resistance among G1, G2, G3, compared to G0.Results:Of 7996 TB cases enrolled, the proportions of G1, G2, G3, and G0 were 8.25%, 3.89%, 16.46%, 71.40%, respectively. The rates of DR-TB, mono-resistant (MR)-TB, multidrug resistant (MDR)-TB, polydrug resistant (PDR)-TB in G1, G2, G3 and G0 were 19.24%/16.4%/17.33%/19.08%, 11.52%/8.68%/10.94%/11.63%, 3.03%/2.57%/2.96%/3.66%, 4.7%/4.82%/3.34%/4.08%, respectively. G3 had a higher risk of MDR1: isoniazid+rifampin (adjusted odds ratio (aOR)=1.913, 95% confidence interval(CI): 1.036-3.532), but had a lower risk of DR-TB (aOR=0.839, 95%CI: 0.712-0.988), rifampin-related resistance (aOR=0.675, 95%CI: 0.492-0.925), streptomycin-related resistance (aOR=0.819, 95%CI: 0.675-0.993), EMB-related resistance (aOR=0.571, 95%CI: 0.342-0.954), MDR3: isoniazid+rifampin+streptomycin (aOR=0.406, 95%CI: 0.194-0.851, any isoniazid+streptomycin resistance (aOR=0.845, 95%CI: 0.714-1). However, there were no significant differences between G1 and G0, G2 and G0 in all drug-resistant sub-types. Those who with cavity had a higher risk of DR-TB among G3 (OR=1.354, 95%CI:1.011-1.814).Conclusions: Although we did not found a independent impact of alcohol drinking or tobacco smoking on TB drug-resistance respectively, these two habits had a joint effect on TB drug-resistance. We should be alert for the emergence of isoniazid+rifampin resistance among populations with both smoking and drinking habits.

A highly sensitive trypsin sensing system in serum was developed by using an anodic alumina oxide (AAO)-based, trypsin substrate-decorated hybrid ion permeation membrane. Owing to the trypsin-triggered peptide hydrolyzation reaction, the surface electrical feature of the peptide-decorated hybrid ion membrane changed. The electric double layer effect reduces the effective ion current diameter in the AAO nano unit, so that the ion current rectification ratio will be enhanced, realizing the quantitative detection of trypsin. The lowest detection concentration can be achieved as low as 0.1 pM. This method is no need for sample pre-preparation, easy to operate, highly sensitive, and also applicable to other enzyme evaluation systems by changing corresponding substrates. This study provides a new idea for selective measurements of proteases in complex biological samples.

A nanotip sensitive to reactive oxygen species (ROS) and NAD+/NADH (oxidized/reduced forms of nicotinamide adenine dinucleotide) was designed and prepared to identify the redox events in a single living cell by surface-enhanced Raman scattering (SERS) spectroscopy. The nanotips were prepared by the one-step laser-induced Ag growth and deposition. A redox-reversible Raman reporter, 4-mercaptophenol (4-MP), was employed for the nanotip decoration along with the Ag deposition. 4-MP can be converted to SERS-inactive 4-mercaptocyclohexa-2,5-dienone (4-MC) by Fe3+ ions to complete signal rezeroing for multiple oxidative stress event loops. The SERS signal conversion from 4-MC to 4-MP provides a cue for the reduction process that is NADH-dependent. In contrast, by the conversion from 4-MP to 4-MC, the oxidative stress events and the signal transduction mechanism of cells stimulated by drugs (phorbol 12-myristate 13-acetate and H2O2) can be explored by SERS. This sensor is easy to fabricate and can be recycled. This tip-typed SERS nanosensor can be extendedly available for tracing other key markers in other NAD+/NADH-mediated respiratory chain and glycolysis, e.g., lactic acid, pyruvic acid, adenosine triphosphate, and antioxidants. It will be useful for investigating the diseases of abnormal oxidative stress and mitochondrial metabolism at the single-cell level.

The anti-tumor effects of metformin hydrochloride (MH), an initial pharmacologic agent for type 2 diabetes, were reexamined by surface-enhanced Raman scattering (SERS) spectroscopy. A SERS immuno-tag fabricated by decorating silver nanoparticles (AgNPs) with a specific antibody was employed to trace the dynamic expression of the tumor metastasis-related N-cadherin. With the MH action, the N-cadherin expression on the cell membranes decreases, proving that MH has a pharmacological effect on prohibiting cancer cell metastasis. Another AgNP-based nucleus targeting nanoprobe was adopted to culture with the MH acted cells, which can help the label-free SERS collection of the cell nuclei to explore the MH influences on intranuclear genes and proteins. By analyzing the intranuclear SERS spectra, the find is that MH has impacts on the transcription and translation of genes, thus regulates the expression of tumor metastasis-related proteins (N-cadherins). This study presents a proof-of-concept for MH as a potential drug for diabetes patients associated with tumors. The developed plasmonic immune analytical platform can be extended to assess other substances of the cell membrane and applicable for the SERS-based screening of membrane receptor-related drugs at the cellular level.

Objective: To measure levels of vitamin A (VA) and vitamin D (VD) and the symptomatic association of their co-deficiencies on attention deficit hyperactivity disorder (ADHD) in Chinese children (6–9 years).Methods: Eighty-two children (69 boys and 13 girls; mean age = 7.1 ± 0.9 years at the time of the diagnosis) with ADHD were recruited as ADHD group. A total of 106 healthy children were recruited as the healthy control (HC) group. Serum levels of retinol and 25-hydroxyvitamin D (25(OH)D) of all children were evaluated using high-performance liquid chromatography (HPLC) and HPLC-tandem mass spectrometry. The Swanson, Nolan, and Pelham IV Rating Scale (SNAP-IV) was employed to assess the clinical symptoms of ADHD.Results: Children suffering from ADHD had significantly reduced serum levels of retinol and 25(OH)D compared with those of HCs, and the prevalence of VA deficiency and VD deficiency were higher in children suffering from ADHD. Serum concentrations of 25(OH)D and retinol were linked closely with the presence or absence of ADHD after adjustment for age, body mass index, season of blood sampling, and sun exposure. Serum concentrations of 25(OH)D and retinol showed a negative correlation with the total scores of SNAP-IV. Children with ADHD as well as VA and VD co-deficiency had increased SNAP-IV total scores and ADHD inattention subscale scores.Conclusion: VA deficiency and VD deficiency in children with ADHD were increased in comparison with that in HCs. VA and VD co-deficiency associated with ADHD symptom severity. Attention should be paid to regular testing of VA levels and VD levels. However, the mechanism of VA and VD in ADHD needs to be further studied. Interventional studies on VA and VD supplementation are recommended to further verify the relationship between VA and VD co-deficiency and ADHD.

The macrolactone rapamycin (RAP) presents a broad range of bioactivities, but its clinical applications are compromised due to the poor water solubility and low bioavailability, which could probably be overcome by glycosylation. In this study, we tested a set of promiscuous glycosyltransferases (GTs) to modify rapamycin with four different sugar donors. BsGT-1 displayed the best glycosylation activity with a preference for UDP-glucose, and the glycosylation happened at C-28 or C-40 of rapamycin, producing rapamycin-40-O-β-D-glucoside (RG1), and two new compounds rapamycin-28-O-β-D-glucoside (RG2) and rapamycin-28,40-O-β-D-diglucoside (RG3). The glycosylation remarkably improved water solubility and almost completely abolished cytotoxicity but simultaneously attenuated the antifungal, antitumor, and immunosuppression bioactivities of rapamycin. We found the glycosylation at C-40 had less effect on the bioactivities than that at C-28. The molecular docking analysis revealed that the glycosylation, especially the glycosylation at C-28, weakened the hydrophobic and hydrogen bonding contacts between the rapamycin glucosides and the binding proteins: the FK506-binding protein (FKBP12) and the FKBP12-rapamycin binding (FRB) domain. This study highlights a succinct approach to expand the chemical diversity of the therapeutically important molecule rapamycin by using promiscuous glycosyltransferases. Moreover, the fact that glycosyl moieties at different positions of rapamycin affect bioactivity to different extents inspires further glycosylation engineering to improve properties of rapamycin. KEY POINTS: • Rapamycin was glycosylated efficiently by some promiscuous GTs. • Glycosylation improved water solubility, attenuated cytotoxicity, and bioactivities. • Glycosylation affected the interactions between ligand and binding proteins.

Myxococcus xanthus DK1622 has two RecA genes, recA1 (MXAN_1441) and recA2 (MXAN_1388) with unknown differentiated functions. Herein, we showed that both recA genes were induced by ultraviolet (UV) irradiation, but the induction of recA1 was more delayed than that of recA2. Deletion of recA1 did not affect the growth, but significantly decreased the UV-irradiation survival, homologous recombination ability, and induction of the LexA-dependent SOS genes. In contrast, the deletion of recA2 markedly prolonged the lag phase of bacterial growth and DNA damage caused by hydrogen peroxide, but did not change the UV-radiation resistance and the SOS-gene inducibility. Protein activity analysis demonstrated that RecA1, but not RecA2, catalyzed DNA strand exchange and LexA-autocleavage in vitro. Transcriptomic analysis indicated that RecA2 has evolved to mainly regulate the gene expressions for cellular transportation and antioxidation. This is the first report of functional divergence of duplicated bacterial recA genes. The results highlight the evolutionary strategy of M. xanthus cells for the DNA homologous recombination and the evolution of genomes from simple to complex.

Dihydrotanshinone (DIH) is an extract of Salvia miltiorrhiza Bunge. It has been reported that DIH could regulate NF-κB signaling pathway. The aim of this study was to investigate whether DIH could protect mice from lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. In this study, sixty mice were randomly divided into five groups, one group as blank control group, the second group as LPS control group, and the last three groups were pre-injected with different doses of DIH and then inhaled LPS for experimental comparison. After 12 h of LPS treatment, the wet-dry ratio, histopathlogical changes, and myeloperoxidase (MPO) activity of lungs were measured. In addition, ELISA kits were used to measure the levels of TNF-α and IL-1β inflammatory cytokines in bronchoalveolar lavage fluids (BALF), and western blot analysis was used to measure the activity of NF-κB signaling pathway. The results demonstrated that DIH could effectively reduce pulmonary edema, MPO activity, and improve the lung histopathlogical changes. Furthermore, DIH suppressed the levels of inflammatory cytokines in BALF, such as TNF-α and IL-1β. In addition, DIH could also downregulate the activity of NF-κB signaling pathway. We also found that DIH dose-dependently increased the expression of LXRα. In addition, DIH could inhibit LPS-induced IL-8 production and NF-κB activation in A549 cells. And the inhibitory effects were reversed by LXRα inhibitor geranylgeranyl pyrophosphate (GGPP). Therefore, we speculate that DIH regulates LPS-induced ALI in mice by increasing LXRα expression, which subsequently inhibiting NF-κB signaling pathway.

In the present work, by using tobacco cell suspension and wheat seedlings, we studied that eATP (extracellular ATP) released by copper (Cu) stress could act as diffusible signal in alleviating the Cu stress-induced cell death. A semipermeable membrane was fixed in the middle of a plastic box to divide the box into two equal compartments (A and B, respectively). This semipermeable membrane can prevent direct cell-to-cell (or seedling-to-seedling) contact and the diffusion of the macromolecules [such as ATPase (adenosine 5'-triphosphatase)] between these two compartments. The cell suspension directly stressed with CuCl2 was placed in compartment A and was incubated with the untreated cell suspension in compartment B. Such treatment significantly increased the levels of cell death and eATP content of the cell suspension in these two compartments. In contrast, addition of ATPase into the cell suspension directly stressed with CuCl2 decreased the eATP level in these two compartments but further increased the level of cell death in compartment B, compared to no addition of ATPase. Similar results were obtained when tobacco cell suspension was replaced by wheat seedlings. These observations indicate that when Cu stress from compartment A induced the plant cell death in compartment B, ATP transferred from compartment A could play a role in alleviating this cell death. Thus, it is suggested that eATP released by copper stress could act as diffusible signal in alleviating the Cu stress-induced cell death.

A series of novel anthranilic diamides derivatives (7a–s) containing halogen, trifluoromethyl group and cyano group were designed, synthesized, and characterized by melting point, 1H NMR, 13C NMR and elemental analyses. The bioactivity revealed that most of them showed moderate to excellent activities against oriental armyworm (Mythimna separata) and diamondback moth (Plutella xylostella). Above all, the larvicidal activity of 7o against oriental armyworm was 100% and 40% at 0.25 and 0.1 mg L−1, comparable to that of the standard chlorantraniliprole (100%, 0.25 mg L−1 and 20%, 0.1 mg L−1). What is more, 7o against diamondback moth displayed 90% insecticidal activity at 0.01 mg L−1, superior to chlorantraniliprole (45%, 0.01 mg L−1). The experiments 7o on the American cockroach (Periplaneta Americana) heart beating rates (Dorsal vessel) and contractile force were compared with chlorantraniliprole. In addition, 7o could affect the calcium homeostasis in the central neurons of the third larvae of oriental armyworm, which revealed that the ryanodine receptor is the potential target of 7o. The density functional theory (DFT) calculation results revealed the amide bridge, the benzene ring of anthraniloyl moiety and pyrazole ring might play an important role in the insecticidal activity through hydrophobic interactions and π-π conjugations.

Promoter optimization is an economical and effective approach to overexpress heterologous genes and improve the biosynthesis of valuable products. In this study, we swapped the original promoter of the epothilone biosynthetic gene cluster in Myxococcus xanthus with two endogenous strong promoters PpilA and PgroEL1, respectively, which, however, decreased the epothilone production ability. The transcriptional abilities by the two promoters were found to be bloomed in the growth stage but markedly decreased after the growth, whereas the original promoter Pepo functioned majorly after the exponential growth stage. Tandem repeat engineering on the original promoter Pepo remarkably increased epothilone production. The tandem promoter exerted similar expressional pattern as Pepo did in M. xanthus. We demonstrated that differential transcriptional modes markedly affected the efficiency of promoters in controlling the gene expressions for the production of the secondary metabolite epothilones. Our study provides an insight into exploiting powerful promoters to produce valuable secondary metabolites, especially in host with limited known promoters. Electronic supplementary material The online version of this article (10.1007/s00253-018-9023-4) contains supplementary material, which is available to authorized users.

The expression levels of glycans on the surfaces of cancer and normal cells show different, however, this difference is not noticeable enough to distinguish them directly. So, herein, based on the targeted molecular recognition of the glycans on cell surfaces by 4-mercaptophenyl boronic acid (MPBA), a novel surface-enhanced Raman scattering (SERS) nanoprobe (glucose-MPBA@AgNPs) was prepared by inducing controllable assembly of MPBA decorated Ag nanoparticles (MPBA@AgNPs) in a certain level via the bridge of glucose to amplify such a limited difference in SERS measurements. On the basis of the aggregation-induced 3D SERS hot spot effect, this multi-particle nanoprobe possesses over 10 times stronger SERS enhancement ability than the individual MPBA@AgNPs. As the different sialic acid (SA) expression on the surfaces of cancer and normal cells led to the different accumulation of glucose-MPBA@AgNPs, the results we obtained (mean intensities recorded from five cells) indicate the SA amounts on two kinds of cells can provide 5-7 times signal contrast grade in SERS band intensities (P < 0.001). Compared with the monodispersed nanoprobe, our developed nanoprobe amplifies the SA expression difference on cell surfaces and supports high sensitivity for cancer cell recognition, which might be useful in providing highly effective recognition of the edges of tumor tissues in clinic field.

Background The CRISPR/dCas9 system is a powerful tool to activate the transcription of target genes in eukaryotic or prokaryotic cells, but lacks assays in complex conditions, such as the biosynthesis of secondary metabolites. Results In this study, to improve the transcription of the heterologously expressed biosynthetic genes for the production of epothilones, we established the CRISPR/dCas9-mediated activation technique in Myxococcus xanthus and analyzed some key factors involving in the CRISPR/dCas9 activation. We firstly optimized the cas9 codon to fit the M. xanthus cells, mutated the gene to inactivate the nuclease activity, and constructed the dCas9-activator system in an epothilone producer. We compared the improvement efficiency of different sgRNAs on the production of epothilones and the expression of the biosynthetic genes. We also compared the improvement effects of different activator proteins, the ω and α subunits of RNA polymerase, and the sigma factors σ54 and CarQ. By using a copper-inducible promoter, we determined that higher expressions of dCas9-activator improved the activation effects. Conclusions Our results showed that the CRISPR/dCas-mediated transcription activation is a simple and broadly applicable technique to improve the transcriptional efficiency for the production of secondary metabolites in microorganisms. This is the first time to construct the CRISPR/dCas9 activation system in myxobacteria and the first time to assay the CRISPR/dCas9 activations for the biosynthesis of microbial secondary metabolites. Electronic supplementary material The online version of this article (10.1186/s12934-018-0867-1) contains supplementary material, which is available to authorized users.

Myricetin is a flavonoids compound extracted from edible myrica rubra. We aimed to evaluate the efficacy of Myricetin on colonic chronic inflammation and inflammation-driven tumorigenesis in mice. Myricetin was administrated by gavage for 4 consecutive weeks. Mice were sacrificed and the number of colonic polyps was counted. Myricetin significantly inhibited AOM/DSS-induced colitis and colorectal tumorigenesis. Myricetin prevented the incidence of colorectal tumorigenesis and reduced the size of colorectal polyps. Histopathologic analysis showed that Myricetin could attenuate the degree of colonic inflammation and colorectal tumorigenesis. Further analysis showed that Myricetin strongly reduced the levels of inflammatory factors TNF-α, IL-1β, IL-6, NF-κB, p-NF-κB, cyclooxygenase-2 (COX-2), PCNA and Cyclin D1 in the colonic tissues as analyzed by the assays of immunohistochemical staining, Western blotting and Q-RT-PCR. Our results demonstrated that Myricetin possesses the biological activities of chemoprevention colonic chronic inflammation and inflammation-driven tumorigenesis. We suggest that Myricetin could be developed as a promising chemopreventive drug for reducing the risk of colorectal cancer.

Reducing CO 2 emissions has become a major and urgent environmental goal worldwide. In this paper, we sample the data of 41 regions (including 165 countries) from 2000 to 2014 and adopt a gravity model to obtain an overview of the global flows of CO 2 emissions, energy consumption, the global economy and capital stock since the beginning of the 21st century. We then investigate global technical efficiency, reduction potential, shadow prices and factors influencing the marginal abatement costs of CO 2 emissions based on a quadratic directional output distance function. The empirical results show the following: (1) the global centres of gravity for CO 2 emissions, energy consumption and capital stock have accelerated their shift to the Asian inland in the 21st century, but the global centre of gravity for the economy did not show the same trend. (2) Global technical inefficiency demonstrates a U-shape, with a turning point in 2007. Average annual total global CO 2 emissions could be reduced by 4482.28 Mt, and the global marginal abatement costs of CO 2 emissions are approximately 673.74–697.73 USD/t. (3) The relationship between economic development and marginal abatement costs is represented by a U-shaped curve. The world is currently in the climbing phase of this curve, implying that controlling CO 2 emissions is becoming more costly. Moreover, energy structure, industrial structure, and CO 2 emissions are negatively correlated with marginal abatement costs. Finally, the financial crisis has had a significant effect on marginal abatement costs.

To date, most studies about the aging of metals in soil were based on the controlled laboratory experiments, and few works have attempted to investigate how aging process influences the distribution and bioavailability of metals in soil under the field condition. The purpose of this study was to compare the aging of cadmium (Cd) in soils under the controlled laboratory and the field by monitoring time-dependent soil Cd speciation changes, Cd release kinetics, and Cd bioavailability to plant through the 438-day aging experiments. During the aging process, the proportions of Cd associated with the most weakly bound fraction tended to decrease, with corresponding increases in the more stable binding fractions. After aging, a higher concentration of available Cd was found in the field aging soil (0.74 mg kg−1) than the laboratory aging soil (0.65 mg kg−1). The Elovich equation was the best model to describe the soil available Cd aging process. The constant b in the Elovich equation, which was defined as the transformation rate, was in the order of laboratory aging soil > field aging soil. Moreover, higher Cd release amounts were found for the field aging soil (2.74 mg kg−1) than the laboratory aging soil (2.57 mg kg−1) at the end of aging. Additionally, higher body Cd concentrations were found for the vegetables grown in the field aging soils (1.49 mg kg−1, fresh weight) than those grown in the laboratory aging soils (1.32 mg kg−1, fresh weight). Therefore, this study indicated that the metal distribution process and its bioavailability may be overestimated or underestimated if research data from the laboratory experiments are used to derive soil quality criteria or investigate soil metal bioavailability.

This study aimed to investigate the relationships between environmental exposure to metals/metalloids and semen quality, sperm apoptosis and DNA integrity using the metal/metalloids levels in seminal plasma as biomarkers. We determined 18 metals/metalloids in seminal plasma using an inductively coupled plasma-mass spectrometry among 746 men recruited from a reproductive medicine center. Associations of these metals/metalloids with semen quality (n = 746), sperm apoptosis (n = 331) and DNA integrity (n = 404) were evaluated using multivariate linear and logistic regression models. After accounting for multiple comparisons and confounders, seminal plasma arsenic (As) quartiles were negatively associated with progressive and total sperm motility using multivariable linear regression analysis, which were in accordance with the trends for increased odds ratios (ORs) for below-reference semen quality parameters in the logistic models. We also found inverse correlations between cadmium (Cd) quartiles and progressive and total sperm motility, whereas positive correlations between zinc (Zn) quartiles and sperm concentration, between copper (Cu) and As quartiles and the percentage of tail DNA, between As and selenium (Se) quartiles and tail extent and tail distributed moment, and between tin (Sn) categories and the percentage of necrotic spermatozoa (all Ptrend

Shengjiang Xiexin decoction (SXD) exerts protective effects against gastrointestinal injury induced by irinotecan hydrochloride (CPT-11). The intestinal bacteria-associated in vitro pharmacokinetics of 16 components of SXD in normal rats and those with CPT-11-induced gastrointestinal toxicity were compared in this study. A sensitive and reproducible ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) method was developed for the quantification of 16 components of SXD in a rat intestinal bacteria incubation system, using naringin, naringenin and tetrahydropalmatine as internal standards (ISs). The samples were prepared via salting-out assisted liquid–liquid extraction (SALLE) with NaCl to reduce matrix effects. Chromatographic separation was performed on a sub-2 μm analytical column with acetonitrile and 0.1% aqueous formic acid as mobile phase. All of the analyzed components and ISs were detected via multiple reaction monitoring (MRM) scanning with electrospray ionization. The proposed method was successfully applied for the in vitro pharmacokinetic analysis of the multiple components of a complex mixture consisting of a traditional Chinese medicine (TCM) and an intestinal bacterial incubation system. The pharmacokinetic parameters of some flavonoid glycosides and aglycones in the rats with CPT-11-induced gastrointestinal toxicity were significantly different (p < 0.05, p < 0.01) from those in the normal rats, which suggested that consumption of CPT-11 could qualitatively and/or quantitatively alter the intestinal bacteria as well as the metabolic activities of enzymes. The in vitro pharmacokinetic analysis of these components in the intestinal bacterial incubation system provided valuable information for achieving a deeper understanding of the mechanisms involved in the alteration of intestinal bacteria induced by CPT-11 and further in vivo pharmacokinetic research on SXD. The intestinal bacteria-based pharmacokinetic method could benefit the study of interactions between TCMs and chemical drugs in clinical use.

Two polysaccharides, named DOP-1 and DOP-2, with molecular weights of 6.8 kDa and 14.3 kDa, respectively, were isolated and purified from the stems of Dendrobium officinale. Monosaccharide composition, Fourier-transform infrared spectroscopy, methylation, and nuclear magnetic resonance analyses indicated that DOP-1 and DOP-2 may have a backbone consisted of →4)-β- d -Glcp-(1→, →4)-β- d -Manp-(1→, →4)-2-O-acetyl-β- d -Manp-(1→ and →4)-3-O-acetyl-β- d -Manp-(1→. In vivo assays showed that D. officinale polysaccharides (DOPs) exerted significant hypoglycemic effects accompanying increased serum insulin and glucagon-like peptide-1 (GLP-1) levels in streptozotocin-induced diabetic rats. Further in vitro experiments showed that DOP-induced GLP-1 secretion was inhibited by an intracellular calcium chelator, a Ca2+/calmodulin-dependent protein kinase (CaMK) II inhibitor, a specific calcium-sensing receptor antagonist, and a p38-mitogen-activated protein kinases (MAPK) inhibitor. These results indicated that DOPs may decrease fasting blood sugar levels by stimulating GLP-1 secretion and that intracellular DOP-induced GLP-1 secretion involved the Ca2+/calmodulin/CaMKII and MAPK pathways.

RecA is a ubiquitous multifunctional protein for bacterial homologous recombination and SOS response activation.Myxococcus xanthusDK1622 possesses tworecAgenes, and their functions and mechanisms are almost unclear. Here, we showed that the transcription ofrecA1(MXAN_1441) was less than one-tenth ofrecA2(MXAN_1388). Expressions of the tworecAgenes were both induced by ultraviolet (UV) irradiation, but in different periods. Deletion ofrecA1did not affect the growth, but significantly decreased the UV-irradiation survival, the homologous recombination ability, and the induction of the LexA-dependent SOS genes. Comparably, the deletion ofrecA2markedly prolonged the lag phase for cellular growth and antioxidation of hydrogen peroxide, but did not change the UV-irradiation resistance and the SOS-gene inducibility. The two RecA proteins are both DNA-dependent ATPase enzymes. We demonstrated that RecA1, but not RecA2, hadin vitroDNA recombination capacity and LexA-autolysis promotion activity. Transcriptomic analysis indicated that the duplicate RecA2 has evolved to mainly regulate the gene expressions for cellular transportation and antioxidation. We discuss the potential mechanisms for the functional divergence. This is the first time to clearly determine the divergent functions of duplicatedrecAgenes in bacterial cells. The present results highlight that the functional divergence of RecA duplicates facilitates the exertion of multiple RecA functions.Author summaryMyxobacteria has a large-size genome, contains many DNA repeats that are rare in the prokaryotic genome. It encodes bacterial RecA that could promote recombination between homologous DNA sequences. How myxobacteria avoid the undesired recombination between DNA repeats in its genome is an interesting question.M. xanthusencodes two RecA proteins, RecA1 (MXAN_1441) and RecA2 (MXAN_1388). Both RecA1 and RecA2 shows more than 60% sequence consistency withE. coliRecA (EcRecA) and can partly restore the UV resistance ofE. coli recAmutant. Here, our results proved their divergent functions of the two RecAs. RecA1 retains the ability to catalyze DNA recombination, but its basal expression level is very low. RecA2 basal expression level is high, but no recombination activity is detected in vitro. This may be a strategy forM. xanthusto adapt to more repetitive sequences in its genome and avoid incorrect recombination.HighlightsM. xanthushas tworecAs, which are expressed with significantly different levels. BothrecAs are inducible by UV irradiation, but in different stages.The absence ofrecA1reduces bacterial UV-irradiation resistance, while the absence ofrecA2delays bacterial growth and antioxidant capacity.RecA1 retains the DNA recombination and SOS induction abilities, while RecA2 has evolved to regulate the expression of genes for cellular transport and antioxidation.

A kind of smart carbon nanodots (CNDs) with the pH response feature was prepared by the one-pot hydrothermal treatment of citric acid and dicyandiamide, which was used for the differentiation of cancer/normal cells and the selective photothermal therapy (PTT) of cancer cells. When the smart CNDs were cultured with cells, they were highly internalized in the lysosomes of cells. Since the small-sized CNDs (about 5 nm) tends to form aggregation (as large as about 20 nm or even larger) under an acid condition (pH = 4.7) due to the electrostatic attraction produced by the surface protonation, relatively severer aggregation of the CNDs were observed in liver cancer cells (HepG2 cells) relative to normal ones (LO2 cells) due to a relative lower pH in the lysosomes of HepG2 cells, which endows them a new strong absorption band at longer wavelengths (450−900 nm) and a higher photothermal conversion efficiency (42.13 %), benefiting to differentiated PTT. The flow cytometric data indicates strong photothermal ablation (8 min, 509.6 mW/cm2) for cancer cells with the assistance of these smart CNDs achieves 82 % death rate of cancer cells, while much less damage is observed on the normal cells (6.35 %). To the best of our knowledge, this is the first report about CNDs for selective PTT owing to their intrinsic property without the aid of any other targeting ligands. These smart CNDs are also available for other acid-responsive sensing systems, and this study inspires us in the synthesis of near-infrared featured carbon materials.

Subcellular mitochondrion has become a target for improving the therapeutic efficiency and reducing side damage to normal cells via a combination of many therapeutic strategies. However, the underlying molecular mechanisms associated with cell death induced by subcellular dysfunction remain unknown or disputed. In this study, we investigated the dynamic molecular changes of living mitochondria upon phototherapy (photothermal therapy plus photodynamic therapy, PTT & PDT) by surface-enhanced Raman scattering spectroscopy (SERS) and intended to disclose the photo-induced cell death route in breast cancer cells (MCF-7) taking into account the mitochondrion. Indocyanine green (ICG), a Food and Drug Administration (FDA)-approved clinic blood-injection near-infrared angiographic contrast agent and a PTT & PDT drug, was used for the evaluation of the phototherapy effect. The results revealed that the content of phenylalanine (Phe) in mitochondria evidently increased during the phototherapy-induced cell death process. Moreover, the phototherapy-induced cell apoptosis was mainly regulated through the DNA structures. We expect that the understanding of mitochondrial molecular stress responses will be helpful for the diagnosis and therapy of cellular processes associated with mitochondria and provide valuable guidance for the further design and development of more effective therapeutic platforms and methods at the sub-cellular level.

Abnormal cellular biothiol levels are related to many abnormal physiological processes, including cancer, multidrug resistance and Alzheimer's disease, etc. In this study, the nano-aggregates of the background-free surface-enhanced Raman scattering (SERS) tags were constructed and developed for the intracellular biothiol detection via a target-triggered disaggregation process. The plasmonic nano-tags were prepared by coating gold nanoparticles with a Raman reporter (4-mercaptobenzonitrile, MBN), which exhibits a single strong peak in the cellular Raman silent region (1800−2800 cm−1) that can eliminate the background interference of cells. Interestingly, this reporter is also the host ligand for guest mercury ions. The coordination of mercury/cyano group induce the formation of the pre-aggregates of nano-tags and the formed nano-aggregates allowing strong SERS signals of reporters. Intracellular biothiols show higher affinity to mercury ions than the SERS tags do, which can break the hot spot geometry and redisperse tags by taking away mercury ions from nano-aggregates, which dramatically decreases the SERS signals of reporters previously laid on gold nanoparticles. The developed SERS “turn off” method was used for biothiol detections in normal, cancer, drug-resistant cells, and biothiol dynamics during chemotherapy. The results demonstrate that the drug-resistant cells (MCF-ADR) lie in a higher biothiol level than cancer cells (MCF-7 and HepG2), and the normal cells (LO2) give a lower biothiol concentration compared with cancer cells. Moreover, most cancer cells are more sensitive to doxorubicin compared with the normal ones. This study provides an important strategy in learning the cellular processes that are highly associated with intracellular biothiol level.

A high-throughput, dual-channel single cell analytical method is described for the detection of sialic acid (SA) on single cell based on the use of microfluidic droplets integrated with plasmonic imaging and surface-enhanced Raman spectroscopy (SERS) with the assistance of a multifunctional metal nanoparticle-based probe. The multifunctional plasmonic nanoprobe was prepared by modifying silver nanoparticles (AgNPs) with 4-mercaptophenylboronic acid (MPBA) that both warrants SA recognition and acts as a Raman reporter. This nanoprobe is a high-contrast indicator under bright field imaging due to the strong energy loss feature of AgNPs, and also owns possesses a strong SERS enhancement capability toward MPBA. Cells incubated with the plasmonic nanoprobes were isolated in water-in-oil droplets and then were re-dispersed in a chamber array chip. High-precision profiles of SA on a single cell in one droplet were obtained by the bright field imaging and image processing. The SA expression levels on different cell lines (MCF-7, HepG2, SGC and BNL.CL2) traced by SERS spectroscopy were compared. The statistical data among different cell lines confirm that the SA expression levels on cancer cells are much higher than that on normal cells. Single cell analysis further revealed that the cell-to-cell variations are more obvious in cancer cell lines. This study provides a valuable tool for understanding glycan-related biochemical processes. Graphical abstract A high-throughput, dual-channel microfluidic droplet platform succeeded in distinguishing different cancer cell lines at single living cell level integrated with plasmonic imaging and surface-enhanced Raman spectroscopy with assistance of a multifunctional metal nanoparticle-based probe.

Aim The objective of this study is to determine if exuberant sympathetic nerve activity is involved in muscle satellite cell differentiation and myoblast fusion. Methods and results By using immunoassaying and western blot analyses, we found that β1 and β2-adrenergic receptors (AdR) were expressed in C2C12 cells. The differentiated satellite cells exhibited an increased expression of β2-AdR, as compared with the proliferating cells. Continuous exposure of isoprenaline (ISO), a β-AdR agonist, delayed C2C12 cell differentiation, and myoblast fusion in time- and dose-dependent manner. ISO also increased short myotube numbers while decreasing long myotube numbers, consistent with the greater reduction in MyHC1, MyHC2a, and MyHC2x expression. Moreover, continuous exposure of ISO gradually decreased the ratio of PKA RI/RII, and PKA RI activator efficiently reversed the ISO effect on C2C12 cell differentiation and myoblast fusion while PKA inhibitor H-89 deteriorated the effects. Continuous single-dose ISO increased β1-AdR expression in C2C12 cells. More importantly, the cells showed enhanced phospho-ERK1/2 levels, resulting in increasing phospho-β2-AdR levels while decreasing β2-AdR levels, and the specific effects could be abolished by ERK1/2 inhibitor. Furthermore, continuous exposure of ISO induced FOXO1 nuclear translocation and increased the levels of FOXO1 in nuclear extracts while reducing pAKT, p-p38MAPK, and pFOXO1 levels. Conversely, blockade of ERK1/2 signaling partially abrogated ISO effects on AKT, p38MAPK, and FOXO1signaling, which partially restored C2C12 cell differentiation and myoblast fusion, leading to an increase in the numbers of medium myotube along with the increased expression of MyHC1 and MyHC2a. Conclusion Continuous exposure of ISO impedes satellite cell differentiation and myoblast fusion, at least in part, through PKA-ERK1/2-FOXO1 signaling pathways, which were associated with the reduced β2-AdR and increased β1-AdR levels. Electronic supplementary material The online version of this article (10.1186/s13287-019-1160-x) contains supplementary material, which is available to authorized users.

Photodynamic therapy (PDT) involves the uptake of photosensitizers by cancer cells and the irradiation of a light with a specific wavelength to trigger a series of photochemical reactions based on the generation of reactive oxygen, leading to cancer cell death. PDT has been widely used in various fields of biomedicine. However, the molecular events of the cancer cell nucleus during the PDT process are still unclear. In this work, a nuclear-targeted gold nanorod Raman nanoprobe combined with surface-enhanced Raman scattering spectroscopy (SERS) was exploited to investigate the dynamic intranuclear molecular changes of B16 cells (a murine melanoma cell line) treated with a photosensitizer (Chlorin e6) and the specific light (650 nm). The SERS spectra of the cell nucleus during the PDT treatment were recorded in situ and the spectroscopic analysis of the dynamics of the nucleus uncovered two main events in the therapeutic process: the protein degradation and the DNA fragmentation. We expect that these findings are of vital significance in having a better understanding of the PDT mechanism acting on the cancer cell nucleus and can further help us to design and develop more effective therapeutic platforms and methods.

Diabetic foot wound healing is a major clinical problem due to impaired angiogenesis and bacterial infection. Therefore, an effective regenerative dressing is desiderated with the function of promoting revascularization and anti-bacteria. Herein, a multifunctional injectable composite hydrogel was prepared by incorporation of the cerium-containing bioactive glass (Ce-BG) into Gelatin methacryloyl (GelMA) hydrogel. The Ce-BG was synthesized by combining sol-gel method with template method, which maintained spherical shape, chemical structure and phase constitution of bioactive glass (BG). The Ce-BG/GelMA hydrogels had good cytocompatibility, promoted endothelial cells migration and tube formation by releasing Si ion. In vitro antibacterial tests showed that 5 mol % CeO2-containing bioactive glass/GelMA (5/G) composite hydrogel exhibited excellent antibacterial properties. In vivo study demonstrated that the 5/G hydrogel could significantly improve wound healing in diabetic rats by accelerating the formation of granulation tissue, collagen deposition and angiogenesis. All in all, these results indicate that the 5/G hydrogel could enhance diabetic wound healing. Therefore, the development of multifunctional materials with antibacterial and angiogenic functions is of great significance to promote the repair of diabetic wound healing.