Establishment of a high content assay for the identification and characterisation of bioactivities in crude bacterial extracts that interfere with the eukaryotic cell cycle

Identification of highly active compounds from insecticidal plant Oroxylum indicum L. (Vent.) and the induction of apoptosis by lapachol on Sf9 cells

The extraction of biopesticides from plants has become a promising field for agricultural development. To explore a high-efficiency and viable method for the screening of plant compounds with insecticidal activity, we screened for active ingredients in the insecticidal plant, Oroxylum indicum L. Vent, using Sf9 cells. A CCK-8 cytotoxicity assay kit was used for high-throughput screening of 34 compounds contained in O. indicum. The apoptosis-inducing effect of the highly cytotoxic compound on Sf9 cells was investigated by morphological characterization using inverted microscopy, caspase-3 activity assay, and DNA gel electrophoresis. Finally, the biological activity of compounds against aphids was evaluated using the leaf-pest dipping methods and leaf dipping methods. Results showed that among the main compounds identified, lapachol, chrysin, and baicalein had good proliferation inhibitory effects on Sf9 cells, with their recorded IC50 being 11.53 mg/L, 38.39 mg/L, and 42.10 mg/L, respectively. Moreover, the IC50 value of lapachol was lower than the control insecticides rotenone (18.03 mg/L) and fipronil (21.04 mg/L). Apoptosis assay further showed that lapachol promoted the production of caspase-3 and led to DNA fragmentation in Sf9 cells. Lapachol showed high biological activity against Aphis gossypii, Sitobion avenae, and Semiaphis heraclei, with its recorded LC50 being 104.40, 101.80, and 110.29 mg/L, respectively, which were comparable to the activity of the control insecticide rotenone. High-throughput screening of active ingredients in the insecticidal plant O. indicum using Sf9 cells is feasible, and the identification of lapachol as the main aphidicidal active substance is valuable for further study.

Marine Actinomycetes, New Sources of Biotechnological Products

The Actinomycetales order is one of great genetic and functional diversity, including diversity in the production of secondary metabolites which have uses in medical, environmental rehabilitation, and industrial applications. Secondary metabolites produced by actinomycete species are an abundant source of antibiotics, antitumor agents, anthelmintics, and antifungals. These actinomycete-derived medicines are in circulation as current treatments, but actinomycetes are also being explored as potential sources of new compounds to combat multidrug resistance in pathogenic bacteria. Actinomycetes as a potential to solve environmental concerns is another area of recent investigation, particularly their utility in the bioremediation of pesticides, toxic metals, radioactive wastes, and biofouling. Other applications include biofuels, detergents, and food preservatives/additives. Exploring other unique properties of actinomycetes will allow for a deeper understanding of this interesting taxonomic group. Combined with genetic engineering, microbial experimental evolution, and other enhancement techniques, it is reasonable to assume that the use of marine actinomycetes will continue to increase. Novel products will begin to be developed for diverse applied research purposes, including zymology and enology. This paper outlines the current knowledge of actinomycete usage in applied research, focusing on marine isolates and providing direction for future research.

The endo-lysosomal system of bEnd.3 and hCMEC/D3 brain endothelial cells

Background

Brain endothelial cell-based in vitro models are among the most versatile tools in blood–brain barrier research for testing drug penetration to the central nervous system. Transcytosis of large pharmaceuticals across the brain capillary endothelium involves the complex endo-lysosomal system. This system consists of several types of vesicle, such as early, late and recycling endosomes, retromer-positive structures, and lysosomes. Since the endo-lysosomal system in endothelial cell lines of in vitro blood–brain barrier models has not been investigated in detail, our aim was to characterize this system in different models.

Methods

For the investigation, we have chosen two widely-used models for in vitro drug transport studies: the bEnd.3 mouse and the hCMEC/D3 human brain endothelial cell line. We compared the structures and attributes of their endo-lysosomal system to that of primary porcine brain endothelial cells.

Results

We detected significant differences in the vesicular network regarding number, morphology, subcellular distribution and lysosomal activity. The retromer-positive vesicles of the primary cells were distinct in many ways from those of the cell lines. However, the cell lines showed higher lysosomal degradation activity than the primary cells. Additionally, the hCMEC/D3 possessed a strikingly unique ratio of recycling endosomes to late endosomes.

Conclusions

Taken together our data identify differences in the trafficking network of brain endothelial cells, essentially mapping the endo-lysosomal system of in vitro blood–brain barrier models. This knowledge is valuable for planning the optimal route across the blood–brain barrier and advancing drug delivery to the brain.

Electronic supplementary material

The online version of this article (10.1186/s12987-019-0134-9) contains supplementary material, which is available to authorized users.

The Endo-Lysosomal System of Brain Endothelial Cells Is Influenced by Astrocytes In Vitro

Receptor- and adsorptive-mediated transport through brain endothelial cells (BEC) of the blood-brain barrier (BBB) involves a complex array of subcellular vesicular structures, the endo-lysosomal system. It consists of several types of vesicles, such as early, recycling, and late endosomes, retromer-positive structures, and lysosomes. Since this system is important for receptor-mediated transcytosis of drugs across brain capillaries, our aim was to characterise the endo-lysosomal system in BEC with emphasis on their interactions with astrocytes. We used primary porcine BEC in monoculture and in co-culture with primary rat astrocytes. The presence of astrocytes changed the intraendothelial vesicular network and significantly impacted vesicular number, morphology, and distribution. Additionally, gene set enrichment analysis revealed that 60 genes associated with vesicular trafficking showed altered expression in co-cultured BEC. Cytosolic proteins involved in subcellular trafficking were investigated to mark transport routes, such as RAB25 for transcytosis. Strikingly, the adaptor protein called AP1-μ1B, important for basolateral sorting in epithelial cells, was not expressed in BEC. Altogether, our data pin-point unique features of BEC trafficking network, essentially mapping the endo-lysosomal system of in vitro BBB models. Consequently, our findings constitute a valuable basis for planning the optimal route across the BBB when advancing drug delivery to the brain.

A Method for Measurement of Drug Sensitivity of Myeloma Cells Co-Cultured with Bone Marrow Stromal Cells

The tumor microenvironment can profoundly affect tumor cell survival as well as alter antitumor drug activity. However, conventional anticancer drug screening typically is performed in the absence of stromal cells. Here, we analyzed survival of myeloma cells co-cultured with bone marrow stromal cells (BMSC) using an automated fluorescence microscope platform, ScanR. By staining the cell nuclei with DRAQ5, we could distinguish between BMSC and myeloma cells, based on their staining intensity and nuclear shape. Using the apoptotic marker YO-PRO-1, the effects of drug treatment on the viability of the myeloma cells in the presence of stromal cells could be measured. The method does not require cell staining before incubation with drugs, and less than 5000 cells are required per condition. The method can be used for large-scale screening of anticancer drugs on primary myeloma cells. This study shows the importance of stromal cell support for primary myeloma cell survival in vitro, as half of the cell samples had a marked increase in their viability when cultured in the presence of BMSC. Stromal cell–induced protection against common myeloma drugs is also observed with this method.

Getting the whole picture: combining throughput with content in microscopy

The increasing availability and performance of automated scientific equipment in the past decades have brought about a revolution in the biological sciences. The ease with which data can now be generated has led to a new culture of high-throughput science, in which new types of biological questions can be asked and tackled in a systematic and unbiased manner. High-throughput microscopy, also often referred to as high-content screening (HCS), allows acquisition of systematic data at the single-cell level. Moreover, it allows the visualization of an enormous array of cellular features and provides tools to quantify a large number of parameters for each cell. These features make HCS a powerful method to create data that is rich and biologically meaningful without compromising systematic capabilities. In this Commentary, we will discuss recent work, which has used HCS, to demonstrate the diversity of applications and technological solutions that are evolving in this field. Such advances are placing HCS methodologies at the frontier of high-throughput science and enable scientists to combine throughput with content to address a variety of cell biological questions.

Investigation of 1-(4-morpholinophenyl)-3-(4-fluorophenyl)-propenone and 1-(4-morpholinophenyl)-3-(3-fluorophenyl)-propenone as new apoptosis inducers on Spodoptera frugiperda (Sf9) cells

The objective of this study was to examine the toxicity of 1-(4-morpholinophenyl)-3-(4-fluorophenyl)-propenone (A) and 1-(4-morpholinophenyl)-3-(3-fluorophenyl)-propenone (B) on Spodoptera frugiperda (Sf9) cells and the mechanism of the toxicity. By cell-based thiazolyl blue tetrazolium bromide (MTT) assay, we found that the IC(50) were 35.45 μM for A and 31.97 μM for B respectively. Formation of apoptotic bodies was observed at 24 h in the treated cells. There was a significant increase of DNA ladders in the treated Sf9 cells compared to controls. In the presence of 50 μM compound A and B for 24 h, ATP content of Sf9 cells reduced by approximately 50%. Compared to the controls, the significant over-expression of caspase-3 in treated cells was measured by caspase-3 activity kit, and the loss of mitochondrial membrane potential (ΔΨm) was detected in apoptosis cells. The results suggested that the two compounds could be identified as new potent cell apoptosis inducers.