[Professor MA Kun treats infertility caused by uterine dysplasia with kidney deficiency and blood stasis].

Uterine dysplasia is a common cause of infertility. Traditional Chinese medicine has unique advantages in the treatment of this disease. This paper introduces a case of infertility caused by uterine dysplasia treated by Professor MA Kun who adopted the therapy of tonifying kidney and activating blood, aiming to summarize the theoretical foundation and formula principles of Professor MA Kun in the clinical treatment of this disease. The kidney stores essence and governs reproduction. Kidney deficiency is the root cause of infertility. The deficiencies in kidney Qi, Yin, and Yang can result in blood stasis to obstruct the uterus, leading to insufficient source for essence and aggravating kidney deficiency. Kidney deficiency and blood stasis affect each other and form a vicious cycle, resulting in uterine dysplasia due to insufficient nutrition and difficult pregnancy. Therefore, Professor MA Kun believes that kidney deficiency and blood stasis is the key pathogenesis of infertility caused by uterine dysplasia and proposes the treatment principle of tonifying kidney and activating blood. Sufficient essence and Qi in the kidney can resolve stasis and generate blood, thus harmonizing Yin and Yang, which can reach thoroughfare and conception vessels to nourish the uterus and recover the normal physiological function of the uterus. In that case, normal pregnancy is possible. Professor MA Kun attaches importance to the therapeutic principle of supplementing Qi and nourishing blood. In addition, she advocates conforming to changes in the menstrual cycle to promote the development of the uterus and the implantation of fertilized eggs. She also integrates traditional Chinese medicine and western medicine to treat both symptoms and root causes. Professor MA Kun's experience has demonstrated definite clinical effect on this disease and can be taken as a reference.

[Progress in the application of novel nano-materials to the safety analysis of agricultural products].

The quality and safety of agricultural products are strongly related to human livelihood. Thus, the government and consumers have recently paid increased attention to the quality and safety of agricultural products. The development of efficient, rapid, and sensitive analytical methods for detecting pesticides, veterinary drugs, heavy metals, mycotoxins, and environmental pollutants in agricultural products is of great significance. Owing to the complexity of many sample matrices and the low concentration of pollutants in a typical sample, appropriate sample pretreatment steps are necessary to enrich pollutants in agricultural products. Solid-phase extraction (SPE) is the most widely used sample pretreatment technology; in this technique, the adsorbent generally determines the selectivity and efficiency of the extraction process. An increasing number of novel materials have been used as SPE adsorbents. The extraction efficiency, extraction selectivity, and analytical throughput of SPE could be greatly improved by combining these novel materials with various extraction modes (e. g., solid-phase microextraction, dispersed SPE, and magnetic SPE (MSPE)) during sample preparation. Because of their large specific surface area and high affinity toward target analytes, nanomaterials are often used as SPE adsorbents, thereby greatly improving the selectivity and sensitivity of the analytical technology. More importantly, these materials have become a priority area of research on preconcentration technologies for trace compounds in agricultural products. This paper summarizes the adsorption characteristics of several new nanomaterials, including magnetic materials, carbon-based materials, metal nanomaterials (MNs), metal oxide nanomaterials (MONs), metal organic frameworks (MOFs), and covalent organic frameworks (COFs). These nanomaterials present numerous advantages, such as large specific surface areas, high adsorption capacities, and tailorable structural designs. MSPE employs magnetic materials as sorbents to afford fast dispersion and efficient recycling when applied to complex sample matrices under an external magnetic field. The use of MSPE can avoid several typical problems associated with SPE such as poor adsorbent packing and high pressure, thereby greatly simplifying the pretreatment process and providing a high flux for sample analysis. Carbon-based materials are powdered or bulk nonmetallic solid materials with carbon as the main component; carbon and nitrogen materials, mesoporous carbon, carbon nanotubes, and graphene are some examples of these materials. These materials provide large specific surface areas, abundant pore structures, good thermal stability, high mechanical strength and adsorption capacity, and controllable morphology. Pure and modified carbon nanomaterials have been successfully used to purify target analytes from agricultural products. Given their unique physical and chemical properties, MNs and MONs have attracted significant interest for use in sample preparation. MNs and MONs with excellent thermal and mechanical stabilities show good resistance to a wide pH range and diverse organic solvents, which is crucial in adsorbent-based extraction methods. The surface of these materials can be easily modified with various ligands to improve their selectivity. MOFs and COFs present many advantages such as large specific surface areas, high porosity, adjustable pore performance, and good thermal stability. Several methods that employ novel adsorbent materials to analyze pollutants in a variety of agricultural products, such as chromatography, spectroscopy, mass spectrometry, and other detection technologies, have been established. This paper also reviews the application of adsorbent materials in the analysis of agricultural product quality and safety, and discusses the future development trends of these sorbents in sample preparation for the safety analysis of agricultural products.

Facile synthesis of non-modified yellow emission silicon quantum dots and their visualization of hydrogen sulfide in living cells and onion tissues.

Yellow fluorescent silicon quantum dots (y-SiQDs) with 22.2% fluorescence quantum yield were synthesized by a simple hydrothermal method using 3-glycidoxypropyl triethoxysilane (GOTS) and m-aminophenol. The excitation wavelength is 550 nm with an emission wavelength of 574 nm, which effectively avoids the interference of biological autofluorescence. Notably, the synthesis approach does not require any post-modification and the y-SiQDs can be directly used for hydrogen sulfide (H2S) quantification due to static quenching. It exhibits high sensitivity and excellent selectivity for H2S with a 0.2-10 µM (R2 = 0.9953) linear range and detection limit of 54 nM. y-SiQDs have excellent stability and biocompatibility and can be used for H2S imaging in living cells and onion tissues.

Network pharmacology and experimental validation identify the potential mechanism of sophocarpine for COVID-19.

Introduction. Coronavirus disease 2019 (COVID-19) has caused a serious threat to public health worldwide, and there is currently no effective therapeutic strategy for treating COVID-19.Hypothesis/Gap Statement. We propose that sophocarpine (SOP) might have potential therapeutic effects on COVID-19 through inhibiting the cytokine storm and the nuclear factor NF-κB signalling pathway.Aim. The objective was to elucidate the potential mechanism of SOP against COVID-19 through a network pharmacology analysis and its experimental validation.Methodology. The BATMAN-TCM database was used to identify the therapeutic targets of SOP, while the GeneCards and DisGeNET databases were used to identify the targets related to COVID-19. A protein-protein interaction (PPI) network was constructed from the STRING and analysed using Cytoscape software. Gene ontology (GO), Kyoto Encyclopaedia of Genes and Genomes (KEGG) and disease ontology (DO) enrichment analyses of the co-targets were performed using Metascape. Autodock 4.2.6 and Pymol software were applied for molecular docking. Levels of the proinflammatory cytokines IL-6, TNFα and IL-1ß were measured by ELISA, while mRNA expression levels of intercellular adhesion molecule 1 (ICAM-1), vascular endothelial growth factor A (VEGFA) and IFN gamma (IFNG) were detected by real-time quantitative reverse transcription PCR. The protein levels of the molecules involved in the NF-κB signalling pathway were validated by western blot analysis.Results. A total of 65 co-targets of SOP and COVID-19 were determined. GO and KEGG enrichment analyses suggested that SOP affected COVID-19 by regulating the IL-17 signalling pathway, TNF signalling pathway and other signalling pathways. The PPI network and molecular docking showed that p65, ICAM-1 and VEGFA were key targets of SOP against COVID-19 and the underlying mechanism was validated in A549 cells in vitro. SOP attenuated the LPS-induced production of TNF-α and IL-6 and downregulated the LPS-induced mRNA expression of ICAM-1, VEGFA and IFNG. Mechanistically, SOP pretreatment inhibited the phosphorylation of p65 and facilitated the activation of Nrf2.Conclusions. SOP has a potential therapeutic effect on COVID-19 through multiple pathways and targets, and inhibits the production of pro-inflammatory cytokines and molecules involved in the NF-κB signalling pathway.

[Clinical efficacy of Bushen Huoxue Culuan Formula in treatment of infertility caused by diminished ovarian reserve due to kidney deficiency and blood stasis].

To study the clinical efficacy and safety of Bushen Huoxue Culuan Formula in treating infertility caused by diminished ovarian reserve(DOR) with kidney deficiency and blood stasis. A total of 100 DOR patients treated at Xiyuan Hospital, Acupuncture Hospital and Clinic of China Academy of Chinese Medical Sciences from 2017 to 2020 in line with the inclusion criteria were selected and randomly divided into experimental group and control group at the ratio of 1∶1. The experimental group was treated with Bushen Huoxue Culuan Formular, while the control group was treated with Climen and Clomiphene for 3 menstrual cycles. The ovulation rate, pregnancy rate, pregnancy success rate, serum hormone levels, and traditional Chinese medicine(TCM) symptom scores were observed in the 2 groups. The total effective rate was 92.00% in the experimental group and 72.00% in the control group, with a statistical difference between the two groups(P<0.01); the experimental group was superior to the control group in reducing FSH level, increasing AMH level, improving TCM symptoms, increasing pregnancy rate and pregnancy success rate, with a significant difference(P<0.05). There was no abnormal safety indicator and adverse reaction. Bushen Huoxue Culuan Formular is effective in treating infertility caused by DOR due to kidney deficiency and blood stasis, with a safety and reliability.

Rapid and Sensitive Detection of Aflatoxin B1, B2, G1 and G2 in Vegetable Oils Using Bare Fe3O4 as Magnetic Sorbents Coupled with High-Performance Liquid Chromatography with Fluorescence Detection.

This paper reports a simple, sensitive and reliable method for the simultaneous detection of aflatoxin B1, B2, G1 and G2 in vegetable oils. Aflatoxins were extracted by magnetic solid phase extraction followed by high-performance liquid chromatography, then postcolumn photochemical derivatization and finally detected by fluorescence detector. Vegetable oil samples were first diluted with hexane and then commercial bare Fe3O4 nanoparticles were directly employed as sorbents to extract aflatoxins from complex vegetable oil samples, which significantly simplified the procedure of sample preparation and largely improved the sample analysis throughput. The effects of various parameters such as the amount of sorbent, loading, washing and eluting conditions were carefully optimized to improve the extraction efficiencies of aflatoxins. Under the optimal conditions, the limits of detection of four aflatoxins ranged from 0.01 µg/kg to 0.16 µg/kg, and squared regression coefficients (R2) >0.9990 were obtained within the linear range of 0.1-20 µg/kg (except for aflatoxin G2 with 0.5-20 µg/kg). Furthermore, the recoveries spiked at four concentration levels in a blank vegetable oil sample were from 82.6 to 106.2%, with inter- and intraday relative standard deviations <9.8%, indicating good accuracy and precision of the proposed method.

Comparative genomics reveal shared genomic changes in syngnathid fishes and signatures of genetic convergence with placental mammals.

Syngnathids (seahorses, pipefishes and seadragons) exhibit an array of morphological innovations including loss of pelvic fins, a toothless tubular mouth and male pregnancy. They comprise two subfamilies: Syngnathinae and Nerophinae. Genomes of three Syngnathinae members have been analyzed previously. In this study, we have sequenced the genome of a Nerophinae member, the Manado pipefish (Microphis manadensis), which has a semi-enclosed brood pouch. Comparative genomic analysis revealed that the molecular evolutionary rate of the four syngnathids is higher than that of other teleosts. The loss of all but one P/Q-rich SCPP gene in the syngnathids suggests a role for the lost genes in dentin and enameloid formation in teleosts. Genome-wide comparison identified a set of 118 genes with parallel identical amino acid substitutions in syngnathids and placental mammals. Association of some of these genes with placental and embryonic development in mammals suggests a role for them in syngnathid pregnancy.

[Clinical efficacy of Bushen Culuan Decoction in treating infertility due to premature ovarian insufficiency].

To analyze the clinical efficiency of traditional Chinese medicine( TCM) Bushen Culuan Decoction in treating anovulatory infertility due to premature ovarian insufficiency( POI). A total of 90 eligible cases were randomly divided into experimental group and control group. The 45 cases in the experimental group took Bushen Culuan Decoction,while the other 45 cases in the control group took estradiol valerate( Progynova),clomiphene( Clomiphene Citrate tablet) and progesterone. The ovulation rate,pregnancy rate,serum hormone level and TCM symptom scale were tested to evaluate the effectiveness of the two therapies. All indexes in experimental group improved significantly after treatment( P<0. 05). The total effectiveness rate was 95. 35% in experimental group and 88. 37% in control group,with a significant difference( P<0. 01). Compared with control group,experimental group had better results in depressing FSH level,elevating AMH level,increasing number of AFC and improving TCM symptom,with significant differences( P < 0. 05). There was no significant difference between experimental group and control group in ovulation rate,pregnancy rate,depressing LH level or elevating E2 level. In this study,Bushen Culuan Decoction is proved to be safe and effective for clinical use in treating infertility due to POI.

Nrf2 mediates the resistance of human A549 and HepG2 cancer cells to boningmycin, a new antitumor antibiotic, in vitro through regulation of glutathione levels.

NF-E2-related factor 2 (Nrf2) is a transcription factor and a pivotal factor in the induction of the cell defense system. Recent reports show that Nrf2 plays critical roles in tumor heterogeneity and drug resistance. In the present study we investigated whether and how Nrf2 mediated the resistance of human cancer cells to boningmycin (BON), a new antitumor antibiotic of the bleomycin family. We showed that in the expression levels of Nrf2 in human non-small lung cancer A549 cells were much higher than those in human hepatoblastoma HepG2 cells, and their resistance to BON was opposite to Nrf2 expression (the IC50values of BON in A549 cells and HepG2 cells were 5.97 and 0.61 µmol/L, respectively). Similar results were observed with the anticancer agent cisdiamminedichloroplatinum (DDP), which was used as a positive control. In A549 cells, Nrf2 mRNA knockdown significantly increased their susceptibilities to BON and DDP. An enhanced resistance to BON and DDP was observed in HepG2 cells after overexpression of the wild-type Nrf2 protein. Treatment with a specific Nrf2 inhibitor, luteolin, significantly sensitized A549 cells to BON and DDP and increased BON- or DDP-induced apoptosis. The total levels of glutathione (GSH), the final product of the Nrf2 signaling pathway, were much higher in A549 cells than those in HepG2 cells. Supplementation of GSH in HepG2 cells significantly decreased their susceptibility to BON and DDP, wheras depleting GSH with the specific inhibitor L-buthionine sulfoximine in A549 cells significantly increased their susceptibility to BON and DDP. Our results demonstrate that Nrf2 mediates the resistance to BON through regulating glutathione levels in A549 cells and HepG2 cells.

Reactive oxygen species scavengers ameliorate mechanical allodynia in a rat model of cancer-induced bone pain.

Cancer-induced bone pain (CIBP) is a frequent complication in patients suffering from bone metastases. Previous studies have demonstrated a pivotal role of reactive oxygen species (ROS) in inflammatory and neuropathic pain, and ROS scavengers exhibited potent antinociceptive effect. However, the role of spinal ROS remains unclear. In this study, we investigated the analgesic effect of two ROS scavengers in a well-established CIBP model. Our results found that intraperitoneal injection of N-tert-Butyl-α-phenylnitrone (PBN, 50 and 100mg/kg) and 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (Tempol, 100 and 200mg/kg) significantly suppressed the established mechanical allodynia in CIBP rats. Moreover, repeated injection of PBN and Tempol showed cumulative analgesic effect without tolerance. However, early treatment with PBN and Tempol failed to prevent the development of CIBP. Naive rats received repetitive injection of PBN and Tempol showed no significant change regarding the nociceptive responses. Finally, PBN and Tempol treatment notably suppressed the activation of spinal microglia in CIBP rats. In conclusion, ROS scavengers attenuated established CIBP by suppressing the activation of microglia in the spinal cord.

[Advantages and evidences research on Chinese medicine for treatment of pelvic inflammatory disease].

Pelvic inflammatory disease is an infectious disease. At present, Western medicine is mainly treated with antibiotics. However, the situation of antibiotics abuse is so grim that the potential risks such as the imbalance of bacteria, the resistance of bacteria, the production of super bacteria and the increase of adverse reactions are becoming more and more serious. Therefore, it is urgent to find a way to supplement or substitute antibiotics for the treatment of this disease. Traditional Chinese medicine treatment of the disease is effective and has its unique advantages. This paper mainly discusses the advantages and evidences of traditional Chinese medicine (TCM) treatment of pelvic inflammatory disease, to further prove the effectiveness and safety of TCM treatment and to provide medical evidence of reducing antibiotics use.

The mitochondrial genome of a sea anemone Bolocera sp. exhibits novel genetic structures potentially involved in adaptation to the deep-sea environment.

The deep sea is one of the most extensive ecosystems on earth. Organisms living there survive in an extremely harsh environment, and their mitochondrial energy metabolism might be a result of evolution. As one of the most important organelles, mitochondria generate energy through energy metabolism and play an important role in almost all biological activities. In this study, the mitogenome of a deep-sea sea anemone (Bolocera sp.) was sequenced and characterized. Like other metazoans, it contained 13 energy pathway protein-coding genes and two ribosomal RNAs. However, it also exhibited some unique features: just two transfer RNA genes, two group I introns, two transposon-like noncanonical open reading frames (ORFs), and a control region-like (CR-like) element. All of the mitochondrial genes were coded by the same strand (the H-strand). The genetic order and orientation were identical to those of most sequenced actiniarians. Phylogenetic analyses showed that this species was closely related to Bolocera tuediae. Positive selection analysis showed that three residues (31 L and 42 N in ATP6, 570 S in ND5) of Bolocera sp. were positively selected sites. By comparing these features with those of shallow sea anemone species, we deduced that these novel gene features may influence the activity of mitochondrial genes. This study may provide some clues regarding the adaptation of Bolocera sp. to the deep-sea environment.

[Features of Professor Ma Kun's medication in treating ovulatory infertility].

In order to analyze Professor Ma Kun's medication in treating anovulatory infertility, her prescriptions for treating anovulatory infertility in 2012-2015 were collected. The medication features and the regularity of prescriptions were mined by using traditional Chinese medicine inheritance support system, association rules, complex system entropy clustering and other mining methods. Finally, a total of 684 prescriptions and 300 kinds of herbs were screened out, with a total frequency of 11 156 times; And 68 core combinations and 8 new prescriptions were mined. The top three frequently used herbs by effect were respectively tonic herb, blood circulation promoting herb, and Qi-circulation promoting herb. The top three tastes were sweetness, bitterness and pungent flavor. The results showed 28 herbs with a high frequency of ≥100.The top 10 frequently used herbs were respectively Angelica Sinensis Radix, Cyperi Rhizoma, Chuanxiong Rhizome, Paeoniae Radix Rubra, Cyathulae Radix, Taxilli Herba, Cuscutae Semen, Codonopsis Radix, Ligustri Lucidi Fructus, Paeoniae Albaand Paeoniae Radix Alba. The association rules analysis showed commonly used herbal pairs, including Rehmanniae Radix Preparata-Chuanxiong Rhizome, Rehmanniae Radix Preparata-Angelica Sinensis Radix, Cuscutae Semen-Dipsaci Radix. In conclusion, Professor Ma has treated anovulatory infertility by nourishing the kidney and activating blood throughout the treatment course, and attached the importance to the relationship between Qi and blood and there gulation of liver, spleen and kidney in treating anovulatory infertility.

[Systematic review on Bushen Huoxue ricipe in treating patients suffering from diminished ovarian reserve].

To systematically evaluate the efficacy and safety of Bushen Huoxue ricipe in treating patients suffering from diminished ovarian reserve. Databases such as CNKI, WanFang, VIP, CBM, PubMed, EMbase and Cochrane Library were searched on randomized controlled trial/quasi-randomized controlled trial about Bushen Huoxue ricipe in treating patients suffering from diminished ovarian reserve form the inception of the study until June 2017. The studies were screened according to inclusion and exclusion criteria. Risk of bias evaluation tools were adopted to conduct quality evaluation. Meta-analysis on outcome indicator was performed by RevMan Version 5.3 Software. Due to the different Bushen Huoxue recipe (observation group) and the different Western medicine(control group) of all included studies, the effect size was combined by the random effect model after the subgroup analysis or sensitivity analysis was performed. Eventually 11 trials were included, including 733 cases of patients. Results of Meta-analysis indicated that, Bushen Huoxue recipe had advantages over Western medicine on lowering FSH, increasing AMH and AFC, enhancing the Chinese medicine symptom curative effect; Bushen Huoxue recipe had no advantages over Western medicine on increasing E2; the advantages of Bushen Huoxue recipe were not clear on reducing FSH/LH and increasing total effective rate because of the different outcomes to compared with the different Western medicine; no serious adverse reaction appering from Bushen Huoxue recipe was reported in the including researches. Bushen Huoxue recipe has the clinical curative effect and high safety suffering from diminished ovarian reserve. However, limited by the poor quantity of studies, these conclusions remain to be examined by more center, more sample and high-quality studies.

Boron-chelating fluorescent probe (BOPB) in the red region combined with CE-LIF for the detection of NO in mice liver.

Precise measurement of nitric oxide (NO) is of great importance to understand the function of NO in liver and the mechanism of liver injury. 8-(3',4'-Diamino phenyl)-3,5-(2-hydroxyphenyl)-dimethylene pyrrole (BOPB), a fluorescent probe in the red region (>600 nm) newly developed in our group, has good photostability and excitation/emission wavelength of 622/643 nm matching well with commercial 635 nm semiconductor laser of CE-LIF detection. Therefore, BOPB was used in CE-LIF for the determination of NO in mice liver. Both derivatization and separation conditions were optimized. Derivatization reaction of BOPB and NO was carried out in pH 7.4 PBS buffer at 35°C for 12 min and the separation of NO derivative of BOPB (BOPB-T) was achieved within 7.0 min in pH 9.0 running buffer containing 15 mM H3 BO3 -NaOH and 15 mM SDS. Good linearity was found in the range of 1.0 × 10(-9) -5.0 × 10(-7) M with the LOD of 0.02 nM. The proposed method was applied to the analysis of NO in real samples, and NO concentration was obviously increased in acute liver injury of mice. Compared to existing derivatization-based CE-LIF methods for NO, this method has lower LOD and less background interference owing to detection wavelength of BOPB in the red region.

Complete mitochondrial genome of the common cutworm Spodoptera litura (Lepidoptera: Noctuidae).

We determined the complete mitochondrial genome of the common cutworm Spodoptera litura (Lepidoptera: Noctuidae), which is one of the most destructive polyphagous insect pests worldwide. The genome is 15,383 bp in length (GenBank accession number: KF701043) with an A+T content of 81.08%, and contains 37 typical animal mitochondrial genes (13 protein-coding genes, 2 rRNA genes and 22 tRNA genes) with the typical arrangement found in Lepidoptera. All the protein-coding genes (PCGs) start with ATN start codon except for cox1, which begins with CGA. Eight PCGs stop with complete termination codons (TAA or TAG), whereas five PCGs use incomplete stop codon T. The A+T-rich region is located between rrnS and trnM with a length of 326 bp and an A+T content of 93.87%, and harbors three tandem repeat elements.

Complete mitochondrial genome of the oriental armyworm Mythimna separata (Walker) (Lepidoptera: Noctuidae).

We determined the complete mitochondrial genome of the oriental armyworm Mythimna separata (Walker) (Lepidoptera: Noctuidae), which is one of the serious cereal pests in Asia and Australia. The circular genome of 15,332 bp in length contains 37 typical animal mitochondrial genes and a non-coding A+T-rich region. Its gene content and order are typical of lepidopteran mitochondrial genomes described to date. All protein-coding genes (PCGs) start with an ATN codon except for cox1 and nad1, which use CGA and TTG as their start codon, respectively. Ten PCGs use complete stop codon TAA, whereas three PCGs end with single T. The A+T-region is located between rrnS and trnM with a length of 374 bp. The mitochondrial genome sequence benefits future studies of molecular phylogenetics and pest control.

Highly sensitive low-background fluorescent probes for imaging of nitric oxide in cells and tissues.

Small-molecule fluorescent probes in combination with fluorescent microscopy can be a powerful tool to provide real-time detection and high spatiotemporal resolution of transient molecules in cells and bodies. For the design of fluorescent probes for transient molecule imaging, high detection sensitivity is crucial. In this report, two new fluorescent probes, 8-(3,4-diaminophenyl)-4,4-difluoro-4-bora-3a,4a-diaza-di(1,2-dihydro)naphtho[b,g]-s-indacene (DANPBO-H) and 8-(3,4-diaminophenyl)-1,7-dimethyl-4,4-difluoro-4-bora-3a,4a-diaza-di(1,2-dihydro)naphtho[b,g]-s-indacene (DANPBO-M), have been developed for nitric oxide (NO) imaging. The detection sensitivity has been efficiently improved by use of these probes through increasing NO detection signals and decreasing background fluorescence. Fluorescence in the far-red region is enhanced by 400- and 550-fold after reaction with NO is achieved and remains stable for at least 24 h under the irradiation of xenon lamp. Excitation and emission wavelengths longer than 600 nm and excellent intracellular retention of these probes and their NO products create dark background inside and outside cells and tissues. What is more, the excellent intracellular retention of these compounds is obtained by their strong lipophilicity, which is a novel design concept diametrically opposite to the traditional approaches. The high sensitivity and dark background make DANPBO-H and DANPBO-M competitive for NO imaging in cells and tissues. The lipophilicity-based intracellular retention mechanism as a design strategy has great potential in the development of fluorescent probes for bioimaging.

Novel B,O-chelated fluorescent probe for nitric oxide imaging in Raw 264.7 macrophages and onion tissues.

A novel fluorescent probe based on B,O-chelated dipyrromethene chromophore in far-visible and near-infrared spectral region (600-900 nm), boron chelated 8-(3,4-diaminophenyl)-3,5-bis(2-hydroxyphenyl)-4-bora-3a,4a-diaza-s-indancene (BOPB), has been first developed for nitric oxide (NO) imaging. BOPB, a turn-on fluorescent probe, can react with NO rapidly under physiological condition. The reaction product of BOPB with NO, BOPB-T, emits bright red fluorescence at 643 nm when excited at 622 nm. Meanwhile, BOPB-T displays high fluorescent quantum yield of 0.21 and good photostability. The selectivity for NO over other reactive oxygen/nitrogen species and ascorbic acid has been investigated and BOPB has good specificity for the detection of NO. MTT assay shows that the toxicity of BOPB (below 10 µM) to living cells can be neglected. Based on these investigations, BOPB has been used for NO imaging in Raw 264.7 cells and onion tissues. Meanwhile, mechanical injury to onion tissues results in a brighter fluorescence around the wound, which indicates that more NO has been produced in plant tissues in response to external stimuli. Our studies illustrate that BOPB has advantages of high sensitivity, low background interference and little photo damage on fluorescence imaging of NO.