The live R bacteria acquired a capsule and
became live, virulent S bacteria.
Fred Griffith found that genetic information could be transferred between different strains of bacteria, specifically between the harmless R strain and the virulent S strain of bacteria. This led to the discovery of transformation, a process where genetic material is exchanged between bacteria.
It depends on how much heat is added. Most pathogenic bacteria are mesophiles, meaning that they thrive in medium temperatures. The optimal temperature is about 37 °C (99 °F), which is understandable considering that is our normal body temperature. Pathogenes in food are required to be killed off with 72 °C for 16 seconds, 70 °C for 2 minutes or 63 °C for 30 min. Regulations depend on country. This does not kill all pathogens, but enough to make it risk free to consume; one wants to reduce the adverse effect on taste at the same time. For conserves a higher temperature is prescribed: 121 °C. Freezing and dry heat are not safe ways to kill bacteria, as they can survive in an extremely resistant spore state (endospores). At 150 °C the DNA starts to be destroyed, however. If you heat bacteria using flame, such as with an inoculating loop over a Bunsen burner, they will be incinerated and die. Most bacteria are washed off, not killed, when you wash your hands. Usually shower and bath water is not hot enough to kill bacteria either. Alcohol is antiseptic, however. Some thermophilic bacterialike organisms can tolerate volcanic temperatures (to 130 °C), but these are archaea that will not harm anyone.
A bacteria cell is where all of you r bacteria gather up
The discovery that DNA is the chemical responsible for transforming live R cells in mice is credited to Frederick Griffith. In his 1928 experiments with Streptococcus pneumoniae, Griffith demonstrated that non-virulent R strain bacteria could be transformed into virulent S strain bacteria when exposed to heat-killed S strain. This transformative principle was later identified as DNA by Avery, MacLeod, and McCarty in 1944.
Streptococcus pneumoniae bacteria is found in two types: a type III-S (smooth) and type II-R (rough) strain. The smooth strain covers itself with a polysaccharide capsule that protects it from the host's immune system, resulting in the death of the host, while the II-R strain doesn't have that protective capsule and is defeated by the host's immune system.The smooth type has a "coat" that prevents it from attacks from the host's immune system and it is very virulent.
The live R bacteria acquired a capsule and became live, virulent S bacteria.
The S bacteria possess a protective polysaccharide capsule that helps them evade the immune system, allowing them to survive and cause infection. The R bacteria lack this capsule and are easily targeted and eliminated by the immune system, thus they are not virulent.
The S bacteria are surrounded by a capsule, so it is not engulfed by the host's white blood cells. That means that it is able to proliferate and spread. The R bacteria lack the capsule (like the mutant S bacteria), so the white blood cells are able to detect and eliminate them.
Fred Griffith found that genetic information could be transferred between different strains of bacteria, specifically between the harmless R strain and the virulent S strain of bacteria. This led to the discovery of transformation, a process where genetic material is exchanged between bacteria.
Griffith hypothesized that a chemical component from the virulent S cells had somehow transformed the R cells into the more virulent S form.
It depends on how much heat is added. Most pathogenic bacteria are mesophiles, meaning that they thrive in medium temperatures. The optimal temperature is about 37 °C (99 °F), which is understandable considering that is our normal body temperature. Pathogenes in food are required to be killed off with 72 °C for 16 seconds, 70 °C for 2 minutes or 63 °C for 30 min. Regulations depend on country. This does not kill all pathogens, but enough to make it risk free to consume; one wants to reduce the adverse effect on taste at the same time. For conserves a higher temperature is prescribed: 121 °C. Freezing and dry heat are not safe ways to kill bacteria, as they can survive in an extremely resistant spore state (endospores). At 150 °C the DNA starts to be destroyed, however. If you heat bacteria using flame, such as with an inoculating loop over a Bunsen burner, they will be incinerated and die. Most bacteria are washed off, not killed, when you wash your hands. Usually shower and bath water is not hot enough to kill bacteria either. Alcohol is antiseptic, however. Some thermophilic bacterialike organisms can tolerate volcanic temperatures (to 130 °C), but these are archaea that will not harm anyone.
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Griffith's transformation experiments, conducted in 1928, involved studying two strains of Streptococcus pneumoniae in mice: a virulent smooth strain (S) and a non-virulent rough strain (R). He discovered that when he injected mice with heat-killed S strain bacteria mixed with live R strain bacteria, the mice developed pneumonia and died. This indicated that some "transforming principle" from the dead S strain had converted the live R strain into a virulent form. Griffith's work laid the groundwork for later discoveries about DNA as the genetic material.
A bacteria cell is where all of you r bacteria gather up
The discovery that DNA is the chemical responsible for transforming live R cells in mice is credited to Frederick Griffith. In his 1928 experiments with Streptococcus pneumoniae, Griffith demonstrated that non-virulent R strain bacteria could be transformed into virulent S strain bacteria when exposed to heat-killed S strain. This transformative principle was later identified as DNA by Avery, MacLeod, and McCarty in 1944.
The S strain of bacteria is virulent due to its ability to produce a protective capsule that helps it evade the host's immune system, allowing it to cause disease in animals. In contrast, the R strain lacks this capsule and is non-virulent, meaning it cannot effectively evade the immune response and does not cause disease. This difference in pathogenicity is a key factor in understanding bacterial infections and their effects on host organisms.
the conversion of R forms of one type into S forms of a different type