3D correlative light and electron microscopy of cultured cells using serial blockface scanning electron microscopy.

The processes of life take place in multiple dimensions, but imaging these processes in even three dimensions is challenging. Here, we describe a workflow for 3D correlative light and electron microscopy (CLEM) of cell monolayers using fluorescence microscopy to identify and follow biological events, combined with serial blockface scanning electron microscopy to analyse the underlying ultrastructure. The workflow encompasses all steps from cell culture to sample processing, imaging strategy, and 3D image processing and analysis. We demonstrate successful application of the workflow to three studies, each aiming to better understand complex and dynamic biological processes, including bacterial and viral infections of cultured cells and formation of entotic cell-in-cell structures commonly observed in tumours. Our workflow revealed new insight into the replicative niche of Mycobacterium tuberculosis in primary human lymphatic endothelial cells, HIV-1 in human monocyte-derived macrophages, and the composition of the entotic vacuole. The broad application of this 3D CLEM technique will make it a useful addition to the correlative imaging toolbox for biomedical research

Antibacterial Activity of 2-Picolyl-polypyridyl-Based Ruthenium (II/III) Complexes on Non-Drug-Resistant and Drug-Resistant Bacteria

A new hexadentate 2-picolyl-polypyridyl-based ligand (4, 4'-(butane-1, 4-diylbis(oxy))bis(N, N-bis(pyridin-2-ylmethyl)aniline)) (2BUT) (1) and its corresponding Ru(II/III) complexes were synthesized and characterized, followed by assessment of their possible bioactive properties towards drug-resistant and non-drug-resistant bacteria. Spectroscopic characterization of the ligand was done using proton NMR, FTIR, and ESI-MS, which showed that the ligand was successfully synthesized. The Ru(II/III) complexes were characterized by FTIR, UV/Vis, elemental analysis, proton NMR, ESI-MS, and magnetic susceptibility studies. The analysis of ESI-MS data of the complexes showed that they were successfully synthesized. Empirical formulae derived from elemental analysis of the complexes also indicated successful synthesis and relative purity of the complexes. The important functional groups of the ligands could be observed after complexation using FTIR. Magnetic susceptibility data and electronic spectra indicated that both complexes adopt a low spin configuration. The disc diffusion assay was used to test the compounds for antibiotic activity on two bacteria species and their drug-resistant counterparts. The compounds displayed antibiotic activity towards the two non-drug-resistant bacteria. As for the drug-resistant organisms, only [Ru2(2BUT)(DMF)2(DPA)2](BH4)43 and 2, 2-dipyridylamine inhibited the growth of MRSA. Gel electrophoresis DNA cleavage studies showed that the ligands had no DNA cleaving properties while all the complexes denatured the bacterial DNA. Therefore, the complexes may have DNA nuclease activity towards the bacterial genomic material

Anticancer Mechanisms of Bioactive Compounds from Solanaceae: An Update

Plants continue to provide unlimited pharmacologically active compounds that can treat various illnesses, including cancer. The Solanaceae family, besides providing economically important food plants, such as potatoes and tomatoes, has been exploited extensively in folk medicine, as it provides an array of bioactive compounds. Many studies have demonstrated the anticancer potency of some of the compounds, but the corresponding molecular targets are not well defined. However, advances in molecular cell biology and in silico modelling have made it possible to dissect some of the underlying mechanisms. By reviewing the literature over the last five years, we provide an update on anticancer mechanisms associated with phytochemicals isolated from species in the Solanaceae plant family. These mechanisms are conveniently grouped into cell cycle arrest, transcription regulation, modulation of autophagy, inhibition of signalling pathways, suppression of metabolic enzymes, and membrane disruption. The majority of the bioactive compounds exert their antiproliferative effects by inhibiting diverse signalling pathways, as well as arresting the cell cycle. Furthermore, some of the phytochemicals are effective against more than one cancer type. Therefore, understanding these mechanisms provides paths for future formulation of novel anticancer drugs, as well as highlighting potential areas of research