What do we mean by viability in terms of 'viable but non-culturable' cells?

A cell line is a population of cells grown in vitro that can be subcultured over several generations. Normal cells cease to divide after a certain number of cell divisions, a process known as replicative senescence. This number, called the Hayflick limit, was conceptualized by Leonard Hayflick in 1961 when he observed that fetal cells grown in culture could only divide 40-60 times. This limit is due to the shortening of the telomeres during each round of cell division, preventing cell division...

Most vertebrate cells grow in vitro attached to a substrate as a monolayer, called adherent cultures. The flasks and plates used to grow cells are chemically treated to facilitate cell attachment. However, a few cell types, such as hematopoietic cells, can grow in a suspension. In contrast to adherent cultures, suspension cultures can grow in non-treated cultureware using magnetic stirrers or spinner flasks to agitate the culture media

Pure cultures, defined as the growth of a single microorganism species isolated from mixed populations, are fundamental tools in microbiological research and practical applications. These cultures ensure genetic and physiological uniformity, allowing researchers to study microbial traits under controlled conditions.Isolation and Maintenance of Pure CulturesObtaining a pure culture involves isolating a single microbial type from a mixed sample through techniques such as serial dilutions, streak...

Stem cell research aims to find ways to use stem cells to regenerate and repair cellular damage. Over time, most adult cells undergo the wear and tear of aging and lose their ability to divide and repair themselves. Stem cells do not display a particular morphology or function. Adult stem cells, which exist as a small subset of cells in most tissues, keep dividing and can differentiate into a number of specialized cells generally formed by that tissue. These cells enable the body to renew and...

Direct methods for measuring microbial populations in a culture are essential tools in microbiology, providing quantitative data for various applications. Among these, microscopic counts, plate counts, and serial dilution are widely used techniques, each with unique principles and applications.Microscopic CountsMicroscopic counting involves the use of a Petroff-Hausser chamber, a specialized microscope slide with a grid and defined depth. By observing a liquid culture under a microscope,...