A spore in biology generally designates a haploid and unicellular reproductive cell. Reproduction by spores allows dispersal and survival for a long time (dormancy) in adverse conditions. The spore produces a new body by dividing by mitosis without fusion with another cell, producing a multicellular gametophyte. The spore is an important element in the biological life cycle of plants, fungi and algae. Spores can be classified according to their function, structure, origin of life cycle or mobility. The term can also refer to the inactive stage of some bacteria, which is more properly called endospores and are not spore in the meaning considered here .Most fungi produce spores, those who do not are called asporogenous fungi. Certain bacteria produce spores as a defense mechanism. Bacterial spores have thick walls and can withstand high temperatures, humidity and other unfavorable conditions. Clostridium bacteria form spores, which produce the live bacteria that cause gas gangrene and antibiotic-associated colitis.
This project has determined the action spectrum of SANIERS prototypes designed to disinfect babies bottles submerged in water using ozonation. According to the aim of the SAINIERS prototype, bacterial strains that may produce gastrointestinal illnesses and health problems via the oral route have been included in the spectrum of antimicrobial activity. The SAINIERS prototype for ozonation was highly effective at disinfecting contaminated water with various bacterial species in suspension. A single cycle of 10 minutes ozonation was enough to reduce 5-6 logarithms of bacterial load, which is above even the requirements established by the AFNOR agency for antiseptic and disinfectant activity (AFNOR, Antiseptiques et désinfectants: Normes et réglementation). Similarly, the ozonator’s action was effective against fungi and yeast, viral particles, even against Geobacillus stearothermophillus spores. In the latter case, it was necessary to apply two ozonization cycles of 10 minutes to achieve disinfection. Below are the results obtained. The tables reflect the bacteria counts obtained before and after ozonation in three independent experiments
Endosporas de Geobacillus stearothermophilus
Endospores are specialized, non-reproductive cells, produced by a few bacteria of the Firmicute division. Their primary function is to ensure survival in times of environmental stress. They are extraordinarily resistant to radiation (ultraviolet, X and gamma), desiccation, lysozyme, heat, chemical disinfectants and mechanical grinding. Endospores are commonly found in soil and water, where they survive for long periods of time.
When a bacterium perceives unfavorable environmental conditions, the sporulation process begins, which can last about 10 hours. DNA is replicated and a membrane wall known as the partition starts to form. The cell’s plasma membrane surrounds this wall forming a double membrane around the DNA and the structure now becomes what is known as forespore. Calcium is incorporated to the forespore. A crust is then formed between the two layers and bacteria add another layer to the forespore. Sporulation is now complete, and the endospore is released when the vegetative cell is degraded. The endospore is very resistant to the majority of agents that would normally kill vegetative cells. House cleaning products usually have no effect, or most alcohols, ammonium compounds or detergents, yet ethylene oxide is effective against endospores. Although they are resistant to extreme heat and radiation, the endospores can be destroyed by these treatments. Thus, exposure to extreme heat for large periods of time and prolonged exposure to the radiation (x-rays or gamma rays for example), will kill most endospores.
Reactivation of the endospore occurs when conditions are more favorable and involves activation and germination. Even if an endospore has favorable conditions, it will not germinate until the activation occurs. Activation is triggered by heat. Germination involves reactivation of the metabolism that breaks the hibernation.
Endospore details have been studied extensively, especially Bacillus subtilis as a simplified model for cell differentiation. These studies have contributed to the study of genes, transcription and units of the sigma factor of the RNA polymerase. Scarily endospores of Bacillus anthracis were used in the 2001 Anthrax attacks. The powder found in letters was contaminated with Anthrax endospores. Ingestion, inhalation or skin contamination with these endospores, incorrectly labeled as "spores", produced many deaths.
Example of sporicidal activity of the SANIERS ozonising equipment. Petri plates where membranes are incubated that come from the filtration 100 ml of water contaminated with spores of Geobacillus stearothermophilus bacteria before and after one or two ozonation treatments.
