![]() ![]() In fact, it has been posited that bacterial spores are among the most resistant life forms and could be one of the longest-living cellular structures. These characteristics allow spores to remain viable and outlast the majority of other organisms. Additionally, spores contain efficient mechanisms for repair of DNA damage during revival, helping them to combat accumulated damage during the spores’ dormancy. The spore core’s properties also contribute to resistance to external stress agents, as it has a low water content, a high concentration of dipicolinic acid (DPA), and its DNA is saturated with α/β -type small acid-soluble spore proteins (SASPs). The spore coat constitutes the initial barrier to potentially harmful molecules, while the compressed inner membrane blocks the entry of many small DNA-damaging chemicals due to its low permeability. ![]() The extreme resistance of a spore is largely due to its multi-layer structure, consisting of (from out- to inside) the proteinaceous coat, the peptidoglycan cortex, the germ cell wall and the inner membrane, all of which surround the spore core that contains the DNA and other biomolecules. Due to the applied importance of bacterial spores in the medical field, the food industry, and extraterrestrial environments, there has been extensive research on spore-forming bacteria.īacterial spores are able to endure a variety of prolonged external stresses such as desiccation, freezing, elevated temperatures in dry or wet conditions, a slew of toxic chemicals, high pressures, as well as UV and γ-radiation. In their inactive state, spores monitor their surrounding environment so that if conditions become favorable, they can break dormancy and resume vegetative cell growth. It allows certain microbes including members of the Bacillus and Clostridium genera to form dormant, multi-layered endospores in response to nutrient depletion. One microbial survival strategy that has been the subject of thorough microbiological investigation is sporulation. Our capacity to explore these questions and begin to understand the mechanisms of microbial survival are continuously improving. ![]() Discoveries on the vast distribution of microbial diversity have continuously challenged fundamental questions such as ‘what are the limitations of life?’. Microorganisms are virtually ubiquitous on Earth, capable of not only tolerating but adapting to nearly any environmental extreme. subtilis were subjected to various short-term storage experiments, revealing that space-like vacuum and high NaCl concentration negatively affected spore viability. Data from the first 2 years of storage show no significant decrease in spore viability. Desiccated baseline spore samples were also exposed to environmental stresses, including X-rays, 254 nm UV-C, 10% H 2O 2, dry heat (120☌) and wet heat (100☌) to investigate how desiccated spores respond to harsh environmental conditions after long periods of storage. subtilis spores is opened and tested for viability every two years for the first 24 years and then every 25 years until experiment completion. A set of vials containing a defined concentration of desiccated B. ![]() In this study, we report the first data from a 500-year microbial experiment, which started in 2014 and will finish in 2514. subtilis spores can lie dormant while remaining viable, a period that potentially far exceeds the human lifespan is not known although convincing examples of long term spore survival have been recorded. Despite thorough study of spore resistance to external stresses, precisely how long B. subtilis is able to tolerate many environmental extremes by transitioning into a dormant state as spores, allowing survival under otherwise unfavorable conditions. Bacillus subtilis) to challenge the limits of microbial resistance and survival. The ability to form endospores allows certain Gram-positive bacteria (e.g. ![]()
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