Establishment and characterization of a multi-drug resistant cell line for canine mammary tumors

Background and purposeCanine mammary tumors are the most common tumor disease of female dogs, and adjuvant chemotherapy often results in multi-drug resistance. Currently, the mechanisms underlying the development of tumor multi-drug resistance are unclear. The translation of research applications that can be used to effectively overcome tumor resistance is similarly hampered. Therefore, it is urgent to construct multi-drug resistance models of canine mammary tumors that can be used for research, to explore the mechanisms and means of overcoming resistance.Materials and methodsIn this study, the canine triple negative breast cancer cell line CMT-7364 was induced to develop multidrug resistance using doxorubicin by high-dose drug pulse method. The drug resistance and the expression of drug transport pumps of the cells was verified by CCK8 assay, immunoblotting, qPCR and immunofluorescence. Next, we used scratch assay and Transwell invasion assay to compare the migration and invasion abilities of the two cell lines and examined the expression of EMT-related proteins in both using immunoblotting. The differences of transcriptome between parental and drug-resistant cell lines were detected by RNA-seq sequencing. Finally, mouse xenograft models of drug-resistant and parental cell lines were constructed to evaluate the tumorigenic ability.ResultsAfter more than 50 generations of continuous passages stimulated by high-dose drug pulse method, the morphology of drug-resistant cell line CMT-7364/R tended to be mesenchymal-like and heterogeneous under light microscopy compared with the parental cell line CMT-7364/S, and developed resistance to doxorubicin and other commonly used chemotherapeutic drugs. In CMT-7364/R, BCRP was expressed at higher levels at both transcriptional and protein levels, while P-glycoprotein was not significantly different. Secondly, the migration and invasion ability of CMT-7364/R was significantly enhanced, with decreased expression of E-cadherin and increased expression of vimentin and mucin 1-N terminus. Finally, mouse xenograft models were constructed, while there was no significant difference in the volume of masses formed at 21 days.ConclusionIn summary, by using the canine mammary tumor cell line CMT-7364/S as the parental cell line, we successfully constructed a multidrug-resistant CMT-7364/R with high-dose drug pulse methods. Compared to its parental cell line, CMT-7364/R has decreased growth rate, overexpression of BCRP and increased migration and invasion ability due to EMT. The results of this study showed that CMT-7364/R might serve as a model for future studies on tumor drug resistance

Photosynthetic Bacterium \u3cem\u3eRhodopseudomonas palustris\u3c/em\u3e GJ-22 Induces Systemic Resistance Against Viruses

Photosynthetic bacteria (PSB) have been extensively used in agriculture to promote plant growth and to improve crop quality. Their potential application in plant disease management, however, is largely overlooked. In this study, the PSB strain Rhodopseudomonas palustris GJ-22 was investigated for its ability to induce resistance against a plant virus while promoting plant growth. In the field, a foliar spray of GJ-22 suspension protected tobacco plants against tobacco mosaic virus (TMV). Under axenic conditions, GJ-22 colonized the plant phyllosphere and induced resistance against TMV. Additionally, GJ-22 produced two phytohormones, indole-3-acetic acid and 5-aminolevulinic acid, which promote growth and germination in tobacco. Furthermore, GJ-22-inoculated plants elevated their immune response under subsequent TMV infection. This research may give rise to a novel biological agent with a dual function in disease management while promoting plant growth

Iterative positive solutions for singular nonlinear fractional differential equation with integral boundary conditions

In this article, we study the existence of iterative positive solutions for a class of singular nonlinear fractional differential equations with Riemann-Stieltjes integral boundary conditions, where the nonlinear term may be singular both for time and space variables. By using the properties of the Green function and the fixed point theorem of mixed monotone operators in cones we obtain some results on the existence and uniqueness of positive solutions. We also construct successively some sequences for approximating the unique solution. Our results include the multipoint boundary problems and integral boundary problems as special cases, and we also extend and improve many known results including singular and non-singular cases

Genome Sequencing of the Sweetpotato Whitefly \u3cem\u3eBemisia tabaci\u3c/em\u3e MED/Q

The sweetpotato whitefly Bemisia tabaci is a highly destructive agricultural and ornamental crop pest. It damages host plants through both phloem feeding and vectoring plant pathogens. Introductions of B. tabaci are difficult to quarantine and eradicate because of its high reproductive rates, broad host plant range, and insecticide resistance. A total of 791 Gb of raw DNA sequence from whole genome shotgun sequencing, and 13 BAC pooling libraries were generated by Illumina sequencing using different combinations of mate-pair and pair-end libraries. Assembly gave a final genome with a scaffold N50 of 437 kb, and a total length of 658 Mb. Annotation of repetitive elements and coding regions resulted in 265.0 Mb TEs (40.3%) and 20 786 protein-coding genes with putative gene family expansions, respectively. Phylogenetic analysis based on orthologs across 14 arthropod taxa suggested that MED/Q is clustered into a hemipteran clade containing A. pisum and is a sister lineage to a clade containing both R. prolixus and N. lugens. Genome completeness, as estimated using the CEGMA and Benchmarking Universal Single-Copy Orthologs pipelines, reached 96% and 79%. These MED/Q genomic resources lay a foundation for future \u27pan-genomic\u27 comparisons of invasive vs. noninvasive, invasive vs. invasive, and native vs. exotic Bemisia, which, in return, will open up new avenues of investigation into whitefly biology, evolution, and management

Fixed point theorems for the sum of three classes of mixed monotone operators and applications

In this paper we develop various new fixed point theorems for a class of operator equations with three general mixed monotone operators, namely A(x,x)+B(x,x)+C(x,x)=x on ordered Banach spaces, where A, B, C are the mixed monotone operators. A is such that for any t∈(0,1), there exists φ(t)∈(t,1] such that for all x,y∈P, A(tx,t−1y)≥φ(t)A(x,y); B is hypo-homogeneous, i.e. B satisfies that for any t∈(0,1), x,y∈P, B(tx,t−1y)≥tB(x,y); C is concave-convex, i.e. C satisfies that for fixed y, C(⋅,y):P→P is concave; for fixed x, C(x,⋅): P→P is convex. Also we study the solution of the nonlinear eigenvalue equation A(x,x)+B(x,x)+C(x,x)=λx and discuss its dependency to the parameter. Our work extends many existing results in the field of study. As an application, we utilize the results obtained in this paper for the operator equation to study the existence and uniqueness of positive solutions for a class of nonlinear fractional differential equations with integral boundary conditions

Existence and uniqueness of solutions for systems of fractional differential equations with Riemann–Stieltjes integral boundary condition

In this article, we first establish an existence and uniqueness result for a class of systems of nonlinear operator equations under more general conditions by means of the cone theory and monotone iterative technique. Furthermore, the iterative sequence of the solution and the error estimation of the system are given. Then we use this new result to study the existence and uniqueness of the solution for boundary value problems of systems of fractional differential equations with a Riemann–Stieltjes integral boundary condition in real Banach spaces. The results obtained in this paper are more general than many previous results and complement them

Research on monitoring technology of surrounding rock stress based on fiber grating

In view of problem of low monitoring efficiency, poor authenticity and accuracy of surrounding rock stress monitoring, a surrounding rock stress monitoring system which can realize real-time online monitoring and long-term monitoring was proposed according to sensor principle and mechanical characteristics of fiber grating. The system applies fiber grating sensing technology to real-time monitoring of surrounding rock stress, and has advantages of high precision, small error and strong anti-interference ability

Preparation and study of Polyvinyl Alcohol/Attapulgite nanocomposite fibers with high strength and high Young’s modulus by gel spinning

Polyvinyl alcohol (PVA)/Attapulgite (ATT) nanocomposite fibers with high strength and high Young’s modulus were prepared via gel spinning. The structures and properties of PVA/ATT nanocomposite fibers were investigated with Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimeter (DSC), thermo gravimetric analysis (TGA), x-ray diffraction (XRD), Environmental scanning electron microscope (ESEM), and mechanical testing. The results showed that ATT had a great influence on the structures and properties of PVA/ATT nanocomposite fibers. The melting temperatures, crystallinities, initial decomposition temperatures and maximum decomposition temperatures of PVA/ATT nanocomposite fibers increased firstly when ATT content was increased from zero to 3 wt%, however, they were then dropped when ATT contents were 5 wt% and 7 wt%. The highest melting temperature, crystallinity, initial decomposition temperature and maximum decomposition temperature of PVA/ATT-3 were 240.4 °C, 67.6%, 266.7 °C and 358.6 °C, respectively. Furthermore, ESEM observation indicated that ATT had good adhesion to PVA matrix. Mechanical tests showed that PVA/ATT-3 had the highest breaking tensile and Young’s modulus of 12.6 cN/dtex and 301.9 cN/dtex, respectively

Research on Gas Concentration Prediction Based on the ARIMA-LSTM Combination Model

The current single gas prediction model is not sufficient for identifying and processing all the characteristics of mine gas concentration time series data. This paper proposes an ARIMA-LSTM combined forecasting model based on the autoregressive integrated moving average (ARIMA) model and the long short-term memory (LSTM) recurrent neural network. In the ARIMA-LSTM model, the ARIMA model is used to process the historical data of gas time series and obtain the corresponding linear prediction results and residual series. The LSTM model is used in further analysis of the residual series, predicting the nonlinear factors in the residual series. The prediction results of the combined model are compared separately with those of the two single models. Finally, RMSE, MAPE and R2 are used to evaluate the prediction accuracy of the three models. The results of the study show that the metrics of the combined ARIMA-LSTM model are R2 = 0.9825, MAPE = 0.0124 and RMSE = 0.083. The combined model has the highest prediction accuracy and the lowest error and is more suitable for the predictive analysis of gas data. By comparing the prediction results of a single model and the combined model on gas time series data, the applicability, validity and scientificity of the combined model proposed in this paper are verified, which is of great importance to accurate prediction and early warning of underground gas danger in coal mines