Death Phase
Death Phase - Related Videos
10:06
An Introduction to Cell Death
0 Views •
2023
Necrosis, apoptosis, and autophagic cell death are all manners in which cells can die, and these mechanisms can be induced by different stimuli, such as cell injury, low nutrient levels, or signaling proteins. Whereas necrosis is considered to be an “accidental” or unexpected form of cell death, evidence exists that apoptosis and autophagy are both programmed and “planned” by cells.In this introductory video, JoVE highlights key discoveries pertaining to cell death, including recent work done...
04:25
Neuronal Death Assay to Evaluate Cell Death in Ex Vivo Epilepsy Model
0 Views •
2025
This video demonstrates the technique of assessing neuronal death in rhinal cortex-hippocampus organotypic slices. Neuronal death occurs via evolving epileptic seizures — resembling in vivo epilepsy — and is detected through dual-staining of the dead cells using propidium iodide and immunofluorescence.
02:39
Phase Diagrams
0 Views •
2020
A phase diagram combines plots of pressure versus temperature for the liquid-gas, solid-liquid, and solid-gas phase-transition equilibria of a substance. These diagrams indicate the physical states that exist under specific conditions of pressure and temperature and also provide the pressure dependence of the phase-transition temperatures (melting points, sublimation points, boiling points). Regions or areas labeled solid, liquid, and gas represent single phases, while lines or curves represent...
01:34
Humane Euthanasia and Confirmation of Death in Rodents
0 Views •
2026
All animal procedures described here must be conducted in accordance with institutional animal ethics guidelines and approved by IACUC. All procedures must follow the principles of the 3Rs—Replacement, Reduction, and Refinement—and must be performed by trained personnel. Humane endpoints in rodents are predefined clinical, behavioral, or physiological indicators that signal an animal is experiencing significant pain, distress, or declining health. When these signs are observed, timely...
02:31
Phase Transitions
0 Views •
2020
Whether solid, liquid, or gas, a substance's state depends on the order and arrangement of its particles (atoms, molecules, or ions). Particles in the solid pack closely together, generally in a pattern. The particles vibrate about their fixed positions but do not move or squeeze past their neighbors. In liquids, although the particles are closely spaced, they are randomly arranged. The position of the particles are not fixed—that is, they are free to move past their neighbors to occupy...
FAQs
Nutrient depletion, oxygen limitation, unfavorable pH, and toxic metabolic waste create sustained stress that progressively damages microbial cells. As stress continues, membranes can lose integrity, metabolic functions can fail, and macromolecules can break down. These changes reduce the number of cells that remain viable and capable of producing colonies or otherwise being detected as living.
A population may stop increasing because cell division is inhibited, yet the cells may still remain viable. Irreversible killing indicates a more severe outcome in which viability has been lost. Separating these possibilities helps researchers interpret environmental stress or antimicrobial treatment correctly, especially when evaluating whether a condition merely prevents growth or reduces microbial survival.
Culturability reflects whether cells retain enough functional capacity to produce detectable growth under the conditions used for analysis. During the Death Phase, membrane damage, metabolic failure, and macromolecular breakdown can reduce culturability as viable cell numbers decline. Consequently, changes in culture-based measurements provide evidence about survival, but they must be interpreted in relation to the conditions being tested.
Researchers follow viable cell numbers over time, beginning after the population has experienced the stresses associated with prolonged culture or treatment. Repeated measurements show whether the population remains stable, declines gradually, or loses viability more rapidly. Comparing these time-dependent survival patterns across conditions helps identify how environmental stress or antimicrobial exposure influences the outcome.
Analysis should account for the factors identified as drivers of cellular stress: nutrient availability, oxygen conditions, pH, and accumulation of toxic metabolic waste. Researchers can compare survival over time under differing conditions to determine which stresses are associated with faster or greater loss of viability. This approach connects population-level decline with the cellular damage that accompanies it.
In antimicrobial studies, monitoring survival over time helps determine whether treatment only suppresses cell division or produces irreversible killing. A decline in viable numbers supports an effect beyond growth inhibition, while continued viability despite limited population increase indicates a different response. This distinction improves interpretation of treatment performance and microbial stress responses.
The stage provides a framework for interpreting why viable cell numbers fall during prolonged culture or unfavorable storage conditions. In bacterial culture analysis and preservation, survival measurements can reveal how environmental stress affects microbial stability. The same reasoning supports evaluation of fermentation systems, where nutrient limitation, oxygen conditions, pH, or waste accumulation may influence population persistence.
Survival measurements show how microorganisms respond when environmental conditions become persistently unfavorable. They can support investigations of stress responses, infection biology, antimicrobial effects, preservation, and fermentation. By tracking the change in viable populations rather than population size alone, researchers can relate environmental conditions to cellular damage, loss of metabolic function, and reduced culturability.