A virus is a microscopic infectious agent that can only multiply within the cells of other organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea. Viruses are too small to be observed with the aid of an optical microscope, so that they are said to be submicroscopic.
Viruses spread in many different ways and each virus type has a different transfer method. Among these methods are the transmission vectors, which are other organisms that transmit them between carriers. Plant viruses often spread by insects that feed on sap, such as aphids, while animal viruses are usually spread by blood-sucking insects. On the other hand, other viruses require no vectors: the influenza virus (rhinovirus) is spread through the air by sneezing and coughing and noroviruses are transmitted by the fecal-oral route, or through contaminated hands, food and water. Rotaviruses are often spread from direct contact with infected children. HIV is one of many viruses transmitted through sexual contact or by exposure to infected blood. Not all viruses cause disease, since many viruses reproduce without causing any damage to the infected organism. Some viruses like HIV can cause permanent or chronic infections as the virus continues to replicate in the body evading host defense mechanisms. In animals, however, it is common for viral infections to produce an immune response conferring permanent immunity to infection. Microorganisms such as bacteria also have defenses against viral infections, known as restriction-modification systems. Antibiotics have no effect on viruses, but antiviral drugs have been developed to treat life-threatening infections.
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
Bacteriofago lambda
The λ phage or bacteriophage lambda is a virus that infects the Escherichia coli bacteria, discovered in 1950. It is a complex linear double-stranded DNA virus. The ends of its genetic material are cohesive and thus makes its genome round after infection, behaving, if it follows a lysogenic cycle, like a plasmid and makes use of the bacteria’s recombination enzymes to integrate its genome. The phage does not have to be integrated, and in fact is more usual to behave as a lytic cycle virus.
In the lysogenic cycle, the virus uses the recombination enzymes (see Hollyday intermediate) to insert itself into a specific point of the bacteria’s genome. In this state, the virus does not replicate when the bacteria does, with its genome passing to be E. coli replicas. Furthermore, a bacteria which has an integrated phage cannot integrate another, as the virus enters a specific location in the bacterial chromosome.
The virus synthesizes from its CI repressor genome, which inhibits the expression of the rest of its genes. Under conditions of cellular stress, the bacteria activate a SOS response. One of the enzymes involved in the response, Rec A (which is also involved in recombination) inhibits CI repressor activity, which results in a cascade response which causes the switch to the integrated lytic virus pathway.
The lytic cycle is the most common way for the virus to infect the cell, and is also the road that leads to the end of the lysogenic cycle. In it, it produces viral particles that are released into the environment after the host bacterium is lysed, killing the bacteria in the process.
The virus replicates its circular genome starting from an easterly point, and unrolling only one of the two strands. The result is a very long linear genome, consisting of a continuous large number of repetitions of the original genome, which is known as a concatamer. The virus also synthesizes its capsid proteins, and is assembled in the cytoplasm of the bacteria. Finally, the cell is lysed, releasing virions into the environment.
Example of virucidal activity from the SANIERS ozonising equipment. Lysis plaques produced by lambda phage particles present in the water samples before and after ozonation treatment on a lawnwith E. coli K308 strain.
