Why are you infected with bacteriophages? What measures should be taken to prevent and control bacte

Symptoms of illness caused by enterohaemorrhagic E. coli include abdominal cramps and diarrhea, and in some cases bloody diarrhea (hemorrhagic colitis).Fever and vomiting may also occur. The incubation period is 3 to 8 days, with an average of 3 to 4 days.

Most patients are within 10 days**, but a small number of patients, particularly young children and older adults, may develop a life-threatening illness, such as hemolytic uremic syndrome (HUS).Hemolytic uremic syndrome is characterized by acute renal failure, hemolytic anemia, and thrombocytopenia. It is estimated that 10% of patients with enterohaemorrhagic E. coli infection can develop hemolytic uremic syndrome, with a case mortality rate of 3% to 5%.

Overall, hemolytic uremic syndrome is the most common cause of acute renal failure in young children. Neurological complications (e.g., seizures, stroke, and coma) occur in 25% of patients with hemolytic uremic syndrome, and chronic kidney disease, usually mild, develops in about 50% of survivors.

The incidence of enterohaemorrhagic E. coli infection varies among age groups, with the highest incidence of reported cases occurring in children under 15 years of age (85% of cases per 100,000 cases in the United States of America are due to foodborne infection). The percentage of enterohemorrhagic E. coli developing hemolytic uremic syndrome varies between sporadic cases (3% to 7%) and outbreak-related cases (20% or more). From an epidemiological point of view, incidental outbreaks generally have a background of scattered cases.

Some outbreaks involved a large number of cases, such as the one that occurred in Japan in 1996, which was associated with the consumption of contaminated radish tassels in school lunches, resulting in 9451 illnesses. Data on this situation in developing countries are limited, as there is no routine surveillance for the pathogen.

Source of infection.

Bacteriophages only infect bacteria, what are you afraid of.

There are four steps, which are:

1. Cultivate E. coli labeled with P32 and S35, and then use E. coli to culture bacteriophages. P32 is used to label bacteriophage proteins, and S35 is used to label bacteriophage DNA.

2. Infect unlabeled E. coli with cultured P32 and S35 phages.

3. Centrifugation and separation of cultures.

4. Detect the radioactivity of the supernatant and the precipitate respectively. S35 is present in the supernatant and almost none in the pellet; There is p32 in the pellet and almost no in the supernatant.

Alfed Hershey and Martha Chase (1952) placed host E. coli cells in medium containing radioisotopes 35S or 32P, respectively, labeling proteins with 35S and egg DNA with 32P. Host cells are labeled with 35s or 32p as they grow. The bacteria labeled by 35S or 32P are then infected with T2 bacteriophage, respectively, and replicated and proliferated in these bacteria.

Host cleavage interpretation releases many progeny phages, which are also labeled with 35s or 32p. The host bacteria that are not labeled with radioisotopes are then infected with phages labeled with 35s or 32p, respectively, and the isotopes carried by the host cells are determined. Few host cells infected by 35s-labeled phages have 35s inside the cells, while most 35s appear outside the host cells.

In other words, the 35S-tagged phage protein coat does not enter the host cell but remains outside the cell after infecting the host cell. After the phage labeled by 32P infected the host bacterial cells, the isotopes of the host bacteria were measured, and it was found that 32P was mainly concentrated in the host bacterial cells. Therefore, when phages infect host bacterial cells, it is mainly DNA that enters the cells.

Bacteriophages are viruses that are able to infect and kill bacteria, and they are tiny organisms that are only a few tens of nanometers in size. Bacteriophages can be widespread in nature, and their traces can be found in soil, grasslands, and water. Bacteriophages can infect various bacteria and use their biological mechanisms to replicate, which is a very efficient way to kill bacteria.

In this article, we will delve into the process of infecting bacteria with bacteriophages, including the following steps.

Step 1: Adhesion.

The first step in phage infection is adhesion, which is the fixation of the phage to the surface of the bacteria. To achieve this, the phage uses its tail to look for some special receptors on the surface of the bacteria. When the phage finds the receptor, it produces some chemical washout reaction that immobilizes the phage to the surface of the bacteria.

This process is similar to the pairing of a key and a lock cylinder, where the phage tail acts like the key and the receptors on the bacterial surface act like the lock cylinder.

Step 2: Inject into the genome.

Once the phage is fixed on the surface of the bacteria, it moves on to the second step: injection into the genome. The phage injects the genome inside the bacterial cell through its tail.

Step 3: Replicate the genome.

When the genome is injected into the bacterial cell, the phage begins to make copies of its own genome. This process is similar to how a bacterial cell makes copies of its own DNA. The material of a bacteriophage is different from that of a bacterial cell.

Bacteriophages use the enzymes, nucleic acids, and other materials of bacterial cells to replicate themselves. This process can be seen as a "great symbiosis".

Step 4: Assemble and crack.

The last step is assembly and cracking. At this stage, the phage genome, proteins, and RNA are assembled into a complete phage history. This process is similar to the manufacturing process of a machine, where each part must be assembled according to certain steps.

When the phage is fully assembled, it ruptures the bacterial cell and releases new phages, which can then infect other bacteria.

In these steps, the process of phage infection with bacteria can be said to be efficient, coordinated, and precise. This type of infection is considered a "natural bactericide" and plays an important role in the ecosystem. In addition, bacteriophages can also be used in food processing, medicine, agriculture and other fields, bringing great convenience and contribution to human life.

The experiment was divided into two groups, one group labeled the protein shell of the phage with 35s, and the result was that the radioactivity was in the supernatant, and the supernatant contained only phage particles, so the conclusion was: the protein shell of the phage did not enter the bacterial body.

The other group labeled the DNA of the bacteriophage with 32p, and as a result, radioactivity was in the precipitate, and it was concluded that the DNA of the phage entered the bacterium.

Overall, the experiment proves that the material that has continuity between the pre-posterity of the phage is DNA, which proves that the traits of the progeny phage are inherited through the DNA of the parent, and DNA is the genetic material of the phage.

It is because DNA is inherited that there is radioactive material outside E. coli.

I remember that the experiment started with the labeling of the parental genetic material, and then the marker would be detected in the offspring.

Answer] Joke book: e

Bacteriophage is a general term for viruses that infect microorganisms such as bacteria, fungi, actinomycetes or spirochetes, and lead has some characteristics of macroviruses, once it leaves the host cell, the phage can neither grow nor replicate, so E is chosen.

Answer]: E bacteriophage is a virus that invades microorganisms, containing only one nucleic acid DNA or RNA, imitation tremor can infect bacterial reflux, fungi, spirochetes and proponction blastoplasma, etc., without infecting viruses.

Adsorption, injection, synthesis, assembly, release. Bacteriophages are viruses that invade bacteria and are also the genetic material that gives biological traits to the host bacteria. Bacteriophages must parasitize within living bacteria and have strict host specificity, which depends on the molecular structure and complementarity of phage adsorption organs and receptors on the surface of the recipient bacteria.

Bacteriophage is a general term for viruses that infect microorganisms such as Sclerotiobacterium, fungi, algae, actinomycetes or spirochetes, and are called bacteriophages because some of them can cause lysis of host bacteria. It was first discovered in staphylococci and shigella at the beginning of this century.

As a type of virus, bacteriophages have some of the characteristics of viruses: tiny individuals; does not have an intact cellular structure; Contains only a single nucleic acid. It can be thought of as a creature that "preys" on bacteria.

The phage genome contains many genes, but all known phages are bacterial cells that use the ribosomes of bacteria, various factors required for protein synthesis, various amino acids, and energy production systems to achieve their own growth and proliferation. Once out of the host cell, the phage can neither grow nor replicate.

Bacteriophage is a kind of virus, and its special feature is that it specializes in bacteria as the host, and the more well-known bacteriophage is the T2 bacteriophage with Escherichia coli as the host. Like other viruses, a bacteriophage is just a mass of genetic material wrapped in a protein shell, and most phages have a "tail" that is used to inject genetic material into the host.

A bacteriophage is a ubiquitous organism and is often accompanied by bacteria. Bacteriophages can usually be found in places full of bacterial communities, such as soil and the internal organs of animals. The richest place in the world to have bacteriophages is seawater.

The narrative about bacteriophages is wrong that bacteriophages can attack a wide variety of microorganisms.

The phenomenon of bacteriophages killing bacteria was discovered in 1915 by Frederick Twater (but Frederick Twater did not study it in depth and did not ask for a name).

In August 1915, the Canadian medical bacteriologist Felix de Herel (Felixd'Herelle also discovered the virus and called it a bacteriophage.

Bacteriophage (phage) is a general term for viruses that infect microorganisms such as bacteria, fungi, algae, actinomycetes or spirochetes.

Categories: Education, Science, >> Learning Aid.

Problem description: Bacteriophage infects bacteria by leaving their outer shells outside, and only DNA goes in to replicate and make proteins. ”

I think the above can already show that DNA is genetic material, why did Hull and Chase do the "phage infection bacteria" experiment in 1952?

Didn't you know the above process before doing this experiment? Or is the above process proven by this experiment?

Analysis: Of course I don't know, the above conclusion was reached by the phage infection bacterial experiment, when they labeled the phage's DNA and protein shell with isotopes, thus proving that DNA and not protein are genetic material.