Zinc-Modified Titanate Nanotubes as Radiosensitizers for Glioblastoma: Enhancing Radiotherapy Efficacy and Monte Carlo Simulations.

Radiotherapy (RT) is the established noninvasive treatment for glioblastoma (GBM), a highly aggressive malignancy. However, its effectiveness in improving patient survival remains limited due to the radioresistant nature of GBM. Metal-based nanostructures have emerged as promising strategies to enhance RT efficacy. Among them, titanate nanotubes (TNTs) have gained significant attention due to their biocompatibility and cost-effectiveness. This study aimed to synthesize zinc-modified TNTs (ZnTNT) from sodium TNTs (NaTNT), in addition to characterizing the formed nanostructures and evaluating their radiosensitization effects in GBM cells (U87 and U251). Hydrothermal synthesis was employed to fabricate the TNTs, which were characterized using various techniques, including transmission electron microscopy (TEM), energy-dispersive spectroscopy, scanning-transmission mode, Fourier-transform infrared spectroscopy, ICP-MS (inductively coupled plasma mass spectrometry), X-ray photoelectron spectroscopy, and zeta potential analysis. Cytotoxicity was evaluated in healthy (Vero) and GBM (U87 and U251) cells by the MTT assay, while the internalization of TNTs was observed through TEM imaging and ICP-MS. The radiosensitivity of ZnTNT and NaTNT combined with 5 Gy was evaluated using clonogenic assays. Monte Carlo simulations using the MCNP6.2 code were performed to determine the deposited dose in the culture medium for RT scenarios involving TNT clusters and cells. The results demonstrated differences in the dose deposition values between the scenarios with and without TNTs. The study revealed that ZnTNT interfered with clonogenic integrity, suggesting its potential as a powerful tool for GBM treatment.

Engineering heterothallic strains in fission yeast.

In poor nitrogen conditions, fission yeast cells mate, undergo meiosis and form spores that are resistant to deleterious environments. Natural isolates of Schizosaccharomyces pombe are homothallic. This allows them to naturally switch between the two h- and h+ mating types with a high frequency, thereby ensuring the presence of both mating partners in a population of cells. However, alteration of the mating type locus can abolish mating type switching or reduce it to a very low frequency. Such heterothallic strains have been isolated and are common in research laboratories due to the simplicity of their use for Mendelian genetics. In addition to the standard laboratory strains, a large collection of natural S. pombe isolates is now available, representing a powerful resource for investigating the genetic diversity and biology of fission yeast. However, most of these strains are homothallic, and only tedious or mutagenic strategies have been described to obtain heterothallic cells from a homothallic parent. Here, we describe a simple approach to generate heterothallic strains. It takes advantage of an alteration of the mating type locus that was previously identified in a mating type switching-deficient strain and the CRISPR-Cas9 editing tool, allowing for a one-step engineering of heterothallic cells with high efficiency.

Long-term evolution of proliferating cells using the eVOLVER platform.

Experimental evolution using fast-growing unicellular organisms is a unique strategy for deciphering the principles and mechanisms underlying evolutionary processes as well as the architecture and wiring of basic biological functions. Over the past decade, this approach has benefited from the development of powerful systems for the continuous control of the growth of independently evolving cultures. While the first devices compatible with multiplexed experimental evolution remained challenging to implement and required constant user intervention, the recently developed eVOLVER framework represents a fully automated closed-loop system for laboratory evolution assays. However, it remained difficult to maintain and compare parallel evolving cultures in tightly controlled environments over long periods of time using eVOLVER. Furthermore, a number of tools were lacking to cope with the various issues that inevitably occur when conducting such long-term assays. Here we present a significant upgrade of the eVOLVER framework, providing major modifications of the experimental methodology, hardware and software as well as a new stand-alone protocol. Altogether, these adaptations and improvements make the eVOLVER a versatile and unparalleled set-up for long-term experimental evolution.

Long-term evolution of proliferating cells using the eVOLVER platform.

Experimental evolution using fast-growing unicellular organisms is a unique strategy for deciphering the principles and mechanisms underlying evolutionary processes as well as the architecture and wiring of basic biological functions. Over the past decade, this approach has benefited from the development of powerful systems for the continuous control of the growth of independently evolving cultures. While the first devices compatible with multiplexed experimental evolution remained challenging to implement and required constant user intervention, the recently-developed eVOLVER framework represents a fully automated closed-loop system for laboratory evolution assays. However, it remained difficult to maintain and compare parallel evolving cultures in tightly controlled environments over long periods of time using eVOLVER. Furthermore, a number of tools were lacking to cope with the various issues that inevitably occur when conducting such long-term assays. Here we present a significant upgrade of the eVOLVER framework, providing major modifications of the experimental methodology, hardware and software as well as a new standalone protocol. Altogether, these adaptations and improvements make the eVOLVER a versatile and unparalleled setup for long-term experimental evolution.

Fluorescence exclusion - a rapid, accurate and powerful method for measuring yeast cell volume.

Cells exist in an astonishing range of volumes across and within species. However, our understanding of cell size control remains limited, owing in large part to the challenges associated with accurate determination of cell volume. Much of our comprehension of size regulation derives from yeast models, but even for these morphologically stereotypical cells, assessment of cell volume has mostly relied on proxies and extrapolations from two-dimensional measurements. Recently, the fluorescence exclusion method (FXm) was developed to evaluate the size of mammalian cells, but whether it could be applied to smaller cells remained unknown. Using specifically designed microfluidic chips and an improved data analysis pipeline, we show here that FXm reliably detects subtle differences in the volume of fission yeast cells, even for those with altered shapes. Moreover, it allows for the monitoring of dynamic volume changes at the single-cell level with high time resolution. Collectively, our work highlights how the coupling of FXm with yeast genetics will bring new insights into the complex biology of cell growth.