Recognition System for Leaf Diseases of Ophiopogon japonicus Based on PCA-SVM

Taking leaf black spot,anthracnose and leaf blight of Ophiopogon japonicus as the research objects,lesions were separated by K-Means clustering segmentation technology.PCA(principal component analysis)was carried out on the 46-dimensional eigenvectors composed of color,shape and texture features,and then the multi-level classifier designed by SVM(support vector machine)was used to identify lesions.The recognition rate of the developed leaf disease recognition system of O.japonicus achieved 93.3%.The results indicates that the system is of great significance to the prevention and control of O.japonicus diseases and the modernization of O.japonicus industry.

Antioxidant Activity of 50 Traditional Chinese Medicinal Materials Varies with Total Phenolics

This study was designed to determine the total phenolic content of 50 herbs and to examine their antioxidant potential. In the sample preparation, 60% ethanol was chosen as the extraction solvent for the subsequent experiments. Folin-Cicolteau phenol reagent and a colorimetric method were used to determine the total phenolic content of the selected herbs. The result showed that total phenolic content of those herbs ranged from 2 to 185 mg/g. In antioxidant assay, the ferric reducing/antioxidant power (FRAP) values ranged from 2 to 134 mg GAE/g;the IC50 values of DPPH?·, ·OH and ?scavenging were in the range of 0.06 - 5.50 mg/mL, 0.017 - 0.636 mg/mL and 0.050 - 0.681 mg/mL respectively. Flos caryophylli was the exceptant in the ?scavenging assay because there was no linear relation between the concentration and the scavenging percentage. Compared to gallic acid, ascorbic acid and butylated hydroxytoluene (BHT) in antioxidant assay as positive control, the most potential antioxidant herbs were Cacumen platycladi, Radix et Rhizoma rhei, Rhizoma rhodiolae crenulatae, and Rhizoma sanguisorbae with considerable content of phenolics. Especially, a positive and significant correlation was found between the total phenolic content and FRAP value or DPPH· scavenging percentage.

Diversity,bioactivities,and metabolic potentials of endophytic actinomycetes isolated from traditional medicinal plants in Sichuan,China

The present study was designed to determine the taxonomic diversity and metabolic activity of the actinomycetes community, including 13 traditional medicinal plants collected in Sichuan province, China, using multiple approaches such as morphological and molecular identification methods, bioactivity assays, and PCR screening for genes involved in antibiotics biosynthesis. 119 endophytic actinomycetes were recovered; 80 representative strains were chosen for 16 S r RNA gene partial sequence analyses, with 66 of them being affiliated to genus Streptomyces and the remaining 14 strains being rare actinomycetes. Antimicrobial tests showed that 12(15%) of the 80 endophytic actinomycetes displayed inhibitory effects against at least one indicator pathogens, which were all assigned to the genus Streptomyces. In addition, 87.5% and 58.8% of the isolates showed anticancer and anti-diabetic activities, respectively. Meanwhile, the anticancer activities of the isolates negatively correlated with their anti-diabetic activities. Based on the results of PCR screening, five genes, PKS-I, PKS-II, NRPS, ANSA, and oxy B, were detected in 55.0%, 58.8%, 90.0%, 18.8% and 8.8% of the 80 actinomycetes, respectively. In conclusion, the PCR screening method employed in the present study was conducive for screening and selection of potential actinomycetes and predicting potential secondary metabolites, which could overcome the limitations of traditional activity screening models.

Screening strategies for quorum sensing inhibitors in combating bacterial infections

Interference with quorum sensing(QS)represents an antivirulence strategy with a significant promise for the treatment of bacterial infections and a new approach to restoring antibiotic tolerance.Over the past two decades,a novel series of studies have reported that quorum quenching approaches and the discovery of quorum sensing inhibitors(QSIs)have a strong impact on the discovery of anti-infective drugs against various types of bacteria.The discovery of QSI was demonstrated to be an appropriate strategy to expand the anti-infective therapeutic approaches to complement classical antibiotics and antimicrobial agents.For the discovery of QSIs,diverse approaches exist and develop in-step with the scale of screening as well as specific QS systems.This review highlights the latest findings in strategies and methodologies for QSI screening,involving activity-based screening with bioassays,chemical methods to seek bacterial QS pathways for QSI discovery,virtual screening for QSI screening,and other potential tools for interpreting QS signaling,which are innovative routes for future efforts to discover additional QSIs to combat bacterial infections.

Modular synthesis of 1,4-diketones through regioselective bis-acylation of olefins by merging NHC and photoredox catalysis

Efficient and modular synthesis of structurally diverse 1,4-diketones from readily available building blocks represents an essential but challenging task in organic chemistry.Herein,we report a multi-component,regioselective bis-acylation of olefins by merging NHC organocatalysis and photoredox catalysis.With this protocol,a broad range of 1,4-diketones could be rapidly assembled using bench-stable feedstock materials.The robustness of this method was further evaluated by sensitivity screening,and good reproductivity was observed.Moreover,the diketone products could be readily converted into functionalized heterocycles,such as multi-substituted furan,pyrrole,and pyridazine.Mechanistic investigations shed light on the NHC and photoredox dual catalytic radical reaction mechanism.

Repurposing vitamin D for treatment of human malignancies via targeting tumor microenvironment

Tumor cells along with a small proportion of cancer stem cells exist in a stromal microenvironment consisting of vasculature, cancer-associated fibroblasts, immune cells and extracellular components.Recent epidemiological and clinical studies strongly support that vitamin D supplementation is associated with reduced cancer risk and favorable prognosis. Experimental results suggest that vitamin D not only suppresses cancer cells, but also regulates tumor microenvironment to facilitate tumor repression. In this review, we have outlined the current knowledge on epidemiological studies and clinical trials of vitamin D. Notably, wesummarized and discussed the anticancer action of vitamin D in cancer cells, cancer stem cells and stroma cells in tumor microenvironment, providing a better understanding of the role of vitamin D in cancer. We presently re-propose vitamin D to be a novel and economical anticancer agent.

Comparative analysis of chemical constituents, antimicrobial and antioxidant activities of ethylacetate extracts of Polygonum cuspidatum and its endophytic actinomycete, Streptomyces sp. A0916

The present study investigated the chemical composition of ethylacetate extracts from an endophytic actinomycete Streptomyces sp. A0916 and its host Polygonum cuspidatum. A comparative analysis of the antimicrobial and antioxidant properties of the extracts was also conducted. 32 compounds of P. cuspidatum and 23 compounds of Streptomyces sp. A0916 were isolated and identified by GC/MS. Antimicrobial activities of the extracts were evaluated using eight microbial strains(3 Gram-positive bacteria, 3 Gram-negative bacteria, and 2 fungi). The Streptomyces sp. A0916 extracts showed a wide range of antimicrobial activities and presented greater antimicrobial effectiveness than the P. cuspidatum extracts. The minimum inhibitory concentration(MIC) of Streptomyces sp. A0916 extracts against the ampicillin-resistant strain Enterococcus faecium SIIA843 was 32 μg·m L-1. Furthermore, the extracts had greater antimicrobial effect against Gram-positive bacteria than Gram-negative bacteria. Finally, the antioxidant activity of the Streptomyces sp. A0916 extracts was equal to that of the P. cuspidatum extracts. In conclusion, our results suggest that the endophytic actinomycetes of the medicinal plants are an important source of bioactive substances.

Characteristics of blood chemistry, hematology, and lymphocyte subsets in pregnant rhesus monkeys

The present study was designed to characterize the blood chemistry, hematology, and lymphocyte subsets in pregnant rhesus monkeys and provide baseline parameters for future studies of reproductive and developmental toxicity and developmental immunotoxicity. Harem-mating was used in 96 female and 16 male rhesus monkeys. Pregnancy was confirmed on gestation day(GD)18 by ultrasound. The blood samples of rhesus monkeys were collected at various times(20 days before pregnancy and GD20, 100 and 150). The analyses of blood chemistry, hematology, and lymphocyte subsets were performed. Copmpared with 20 days before pregnancy, Significant decreases(P < 0.05) were observed in HCT and RBC on GD20, GD150 and in HGB on GD150, Significant increases in NEUT and decreases in LYMPH on GD20 were observed. Significant decreases in ALB from GD20 to GD150 were observed, significant decreases in TP was observed on GD100. Significant increases in mean GLU were observed on GD20 and GD150 during pregnancy. Significant decreases(P < 0.05) in CD20+ subsets on GD100, GD150 and CD4+/CD8+ ratio on GD150 were observed, The significant changes of MCV, MCHC, RDW-SD, MCV, MONO, ALT, AST, GLB, ALP, TBIL, DBIL, IBIL, GGT, CR-S, URIC, TC, TG and CK were observed during the pregnant period, but no biologic change were observed, There were no significant changes in MCH, RDW-CV, MPV, BUN, CD3+, CD4+ and CD8+ during pregnancy. These data provide a database for preclinical study in rhesus monkeys. Physiological anemia, hyperglycemia, and immune suppression may occur in pregnant rhesus monkey which is similar to that found in human, and it is essential to distinguish the physiological changes from the pharmacological effects in reproductive and developmental toxicity and developmental immunotoxicity studies of pharmaceuticals.

NHC-catalysed retro-aldol/aldol cascade reaction enabling solvent-controlled stereodivergent synthesis of spirooxindoles

An N-heterocyclic carbene(NHC)-catalysed retro-aldol/aldol cascade reaction of spirooxindole-basedβ-hydroxyaldehyde has been developed.The ring opening-closure process enables the diastereodivergent synthesis of spirocyclopentaneoxindole products with four consecutive stereocenters by simply changing the reaction solvents(THF or DCE).The Michael/aldol/retro-aldol/aldol sequential protocol allows the diastereodivergent synthesis of spirocyclopentaneoxindoles from 3-substituted oxindole andα,β-unsaturated aldehyde under the relay catalysis of a chiral secondary amine and an NHC catalyst.Moreover,four stereoisomers of the product can be selectively provided by using different combinations of a chiral secondary amine and a solvent.

Organocatalytic asymmetric synthesis of multifunctionalized α-carboline-spirooxindole hybrids that suppressed proliferation in colorectal cancer cells

Organocatalytic asymmetric[3+3]annulations of isatin-derived MBH carbonates and indolin-2-imines were efficiently achieved.This appears to be the first enantioselective approach for using isatin-derived MBH carbonates as 3C synthons to react with indole-derived C,N-dinucleophiles,yielding a series of multifunctionalized α-carboline-spirooxindole hybrids in good to high yields with high stereoselectivities.

Design,synthesis,and bioassay of 5-epi-aminoglycosides

For the purpose of seeking new antibiotics,researchers usually modify the already-existing ones.However,this strategy has been extensively used and is close to its limits,especially in the case of aminoglycosides,and it is difficult to find a proper aminoglycoside antibiotic for novel modification.In this paper,we reported the design,synthesis,and evaluation of a series of 5-epi-neamine derivatives based on the structural information of bacterial 16S RNA A-site binding with aminoglycosides.Bioassay results showed that our design strategy was feasible.Our study offers a new way to search for structurally novel aminoglycosides.Meanwhile,our study provides valuable structure-activity relationship information,which will lead to better understanding and exploitation of the drug target,and improved development of new aminoglycoside antibiotics.

Palladium-catalysed stereoselective[3+2]annulation of vinylethylene carbonates and tryptanthrin-based ketones

The palladium-catalysed[3+2]annulation of vinylethylene carbonates(VECs)and ketones remains challenging in organic synthesis.Herein,we successfully achieved the[3+2]annulation of tryptanthrin-based ketones and VECs for the efficient synthesis of indoloquinazolinone derivatives with generally excellent yields and good diastereoselectivity.Notably,the asymmetric version of this[3+2]annulation can also be achieved by using a chiral spiroketal-based diphosphine ligand.In addition,preliminary biological studies reveal that some of the products exhibit promising antibacterial activity.

Cyasterone inhibits IL-1β-mediated apoptosis and inflammation via the NF-κB and MAPK signaling pathways in rat chondrocytes and ameliorates osteoarthritis in vivo

Osteoarthritis is a prevalent global joint disease,which is characterized by inflammatory reaction and cartilage degradation.Cyasterone,a sterone derived from the roots of Cyathula officinalis Kuan,exerts protective effect against several inflammationrelated diseases.However,its effect on osteoarthritis remains unclear.The current study was designed to investigate the potential antiosteoarthritis activity of cyasterone.Primary chondrocytes isolated from rats induced by interleukin(IL)-1βand a rat model stimulated by monosodium iodoacetate(MIA)were used for in vitro and in vivo experiments,respectively.The results of in vitro experiments showed that cyasterone apparently counteracted chondrocyte apoptosis,increased the expression of collagen II and aggrecan,and restrained the production of the inflammatory factors inducible nitric oxide synthase(iNOS),cyclooxygenase-2(COX-2),a disintegrin and metalloproteinase with thrombospondin motifs-5(ADAMTS-5),metalloproteinase-3(MMP-3),and metalloproteinase-13(MMP13)induced by IL-1βin chondrocytes.Furthermore,cyasterone ameliorated the inflammation and degenerative progression of osteoarthritis potentially by regulating the nuclear factor kappa B(NF-κB)and mitogen-activated protein kinase(MAPK)pathways.For in vivo experiments,cyasterone significantly alleviated the inflammatory response and cartilage destruction of rats induced by monosodium iodoacetate,where dexamethasone was used as the positive control.Overall,this study laid a theoretical foundation for developing cyasterone as an effective agent for the alleviation of osteoarthritis.

Dipyridyl Azo Compound 4,4'-Azopyridine as a Potential Coating Material for Toilet Sanitizer

Good toilet hygiene can reduce the risk of pathogenic transmission.During flushing,pathogenic bacteria can be spread by the water droplets,especially in the toilet seat.Escherichia coli(E.coli)is one of the frequently occurring Gram-negative bacterial pathogens found in the toilet seats.In this study,we investigated the potential anti-E.coli activity of some azobenzene compounds.Among them,compound 2,with the heterocyclic nitrogen in both phenyl rings,showed the strongest antibacterial effect on E.coli,with the minimum inhibitory concentration of 80μg/mL and the minimum bactericidal concentration of 320μg/mL.Compound 2 displayed a comparative zone of clearance[(14.50±2.29)mm]to that of ampicillin[(13.17±1.76)mm].The reactive oxygen species(ROS)assay suggested that compound 2 might induce the loss of bacteria via the oxidative stress by eliciting the generation of intracellular ROS.We further examined the potential cytotoxicity of compound 2 to the human skin HaCaT cells.Compound 2-treated skin cells showed a good maintenance of cellular morphology and a clear definition of cell nuclei,with a satisfactory cell viability(ca.90%)at 80μg/mL.Overall,compound 2 would be a possible antibacterial coating agent for the surface sanitizer of the toilet seats to inhibit the growth of E.coli.

Micellar Catalysis:Visible-Light Mediated Imidazo[1,2-a]pyridine C—H Amination with N-Aminopyridinium Salt Accelerated by Surfactant in Water

A light-promoted metal-free protocol for the amination of imidazo[1,2-a]pyridines with N-aminopyridinium salt by the assistance of surfactants in water was reported,charactering mild and environmentally benign conditions,as well as great functional group tolerance.Micelles with negatively charged polar surface and hydrophobic core formed from sodium dodecyl sulfate serve as an ideal medium for visible-light mediated radical reaction of cationic pyridine salt and imidazo[1,2-a]pyridine in aqueous phase.The electrostatic interaction between positively charged N-aminopyridinium and negatively charged surface of micelles is of great significance in this method.