Bacteria, also called germs, are microscopic organisms not visible with the naked eye. Bacteria are everywhere, both inside and outside of your body. Bacteria can live in a variety of environments, from hot water to ice. Some bacteria are good for you, while others can make you sick.
Bacteria are single-celled, or simple, organisms. Though small, bacteria are powerful and complex, and they can survive in extreme conditions. Bacteria have a tough protective coating that boosts their resistance to white blood cells in the body. Some bacteria have a tail, called a flagellum. The flagellum helps a bacterium to move around. Other bacteria have sticky hair-like appendages that help bacteria them stick to one other, hard surfaces, and human body cells.
There are many bacteria in the human body, especially in the stomach and mouth. Bacteria are found on surfaces and in substances such as water, soil, and food. Bacteria can be aerobic, anaerobic, or facultative anaerobes. These terms describe how they respond to oxygen. Aerobic bacteria need oxygen to live.
Anaerobic bacteria will die around oxygen. Facultative anaerobes function best with oxygen but do not need it. Some bacteria are good for you, including the bacteria in your digestive system, or gut. They make their own food by oxidizing sulfur that comes from deep inside the earth. Some bacteria produce endospores, or internal spores, while others produce exospores, which are released outside. These are known as cysts. Clostridium is an example of an endospore-forming bacterium. There are about species of Clostridium , including Clostridium botulinim C.
Difficile , which causes colitis and other intestinal problems. Bacteria are often thought of as bad, but many are helpful. We would not exist without them. The oxygen we breathe was probably created by the activity of bacteria. Many of the bacteria in the body play an important role in human survival. Bacteria in the digestive system break down nutrients, such as complex sugars, into forms the body can use.
Non-hazardous bacteria also help prevent diseases by occupying places that the pathogenic, or disease-causing, bacteria want to attach to. Some bacteria protect us from disease by attacking the pathogens.
Bacteria take in nitrogen and release it for plant use when they die. Plants need nitrogen in the soil to live, but they cannot do this themselves. To ensure this, many plant seeds have a small container of bacteria that is used when the plant sprouts. Lactic acid bacteria, such as Lactobacillus and Lactococcus together with yeast and molds, or fungi, are used to prepare foods such as as cheese, soy sauce, natto fermented soy beans , vinegar, yogurt, and pickles.
Not only is fermentation useful for preserving foods, but some of these foods may offer health benefits. For example, some fermented foods contain types of bacteria that are similar to those linked with gastrointestinal health. Some fermentation processes lead to new compounds, such as lactic acid, which that appear to have an anti-inflammatory effect. More investigation is needed to confirm the health benefits of fermented foods.
Bacteria can break down organic compounds. This is useful for activities such as waste processing and cleaning up oil spills and toxic waste.
Bacteria are used in molecular biology, biochemistry and genetic research, because they can grow quickly and are relatively easy to manipulate. Scientists use bacteria to study how genes and enzymes work.
Bacillus thuringiensis Bt is a bacterium that can be used in agriculture instead of pesticides. It does not have the undesirable environmental consequences associated with pesticide use. Some types of bacteria can cause diseases in humans, such as cholera , diptheria, dysentery , bubonic plague, pneumonia , tuberculosis TB , typhoid , and many more. If the human body is exposed to bacteria that the body does not recognize as helpful, the immune system will attack them.
This reaction can lead to the symptoms of swelling and inflammation that we see, for example, in an infected wound. In , pneumonia, TB, and diarrhea were the three biggest killers in the United States. Sterilization techniques and antibiotic medications have led to a significant drop in deaths from bacterial diseases.
However, the overuse of antibiotics is making bacterial infection harder to treat. As the bacteria mutate, they become more resistant to existing antibiotics, making infections harder to treat.
Bacteria transform naturally, but the overuse of antibiotics is speeding up this process. For this reason, scientists and health authorities are calling on doctors not to prescribe antibiotics unless it is necessary, and for people to practice other ways of preventing disease, such as good food hygiene, hand washing, vaccination, and using condoms.
Recent research has led to a new and growing awaress of how the human body interacts with bacteria, and particularly the communities of bacteria living in the intestinal tract, known as the gut microbiome, or gut flora. In , researchers published findings suggesting that women with obesity were more likely to have a particular kind of bacteria, Selenomonas noxia S.
But do not worry! Most bacteria are good for us. Some live in our digestive systems and help us digest our food, and some live in the environment and produce oxygen so that we can breathe and live on Earth. But unfortunately, a few of these wonderful creatures can sometimes make us sick.
This is when we need to see a doctor, who may prescribe medicines to control the infection. But what exactly are these medicines and how do they fight with bacteria? When the bacteria stop growing, our bodies can then clear the infection and we feel better. The development of antibiotics is one of the biggest successes of modern medicine.
Antibiotics have saved millions of lives since doctors started using them in the s. Antibiotics have helped humans to have much better lives by successfully treating almost all types of bacterial infections. But like us, bacteria are smart, too!
Since the s, bacteria have been developing tactics to overcome the effects of antibiotics, and today we are seeing more and more bacteria that can no longer be killed by antibiotics at all. If we do not have antibiotics to stop bacterial infections, even something as simple as a small infected cut on the finger could become life-threatening. Therefore, new weapons, in the form of new antibiotics, are needed to treat the infections caused by antibiotic-resistant bacteria.
To find new antibiotics, we first need to fully understand the inner workings of the bacterial cell. Our lab focuses on understanding something very important about how bacteria work—the way bacteria become two cells from one cell, also called the process of bacterial cell division. Like all kinds of organisms, all bacteria need to grow and multiply to survive as a species. When sufficient food is available, bacteria multiply quickly by doubling in size and then splitting in half, to create two new cells [ 1 ].
Bacteria use a kind of machinery inside the cell to do this, which is known as a Z ring green ring in Figure 1. The Z ring forms exactly at the middle of the cell and wraps around the cell.
When the cell divides, this creates two new cells that are the same size. During division, everything inside the cell needs to be copied and equally shared between the two new cells. This includes bacterial DNA shown as brown blobs inside the cell in Figure 1 , which is like a code for bacteria that carries all the information needed for a cell to survive.
If new cells do not receive a full copy of this information, they cannot grow properly and will not survive. The formation of the Z ring at exactly the middle of the cell is essential to produce two healthy cells; otherwise one cell will not contain DNA and will die Figure 1B.
This results in only half of the new bacterial cells surviving, which is not so good for bacterial growth. Here comes a very interesting question—how does a bacterial cell make sure that the Z ring forms only in the middle of the cell and not anywhere else in the cell? The place where the Z ring forms is so important that it is under the control of many systems [ 2 ] that work together to stop the Z ring from forming anywhere other than the middle of the cell.
In addition to making sure that the Z ring forms at the right place, a cell also needs to sense the correct time to form the Z ring and to divide. This depends very much on the environment that the bacteria are in.
For example, if it is extremely cold or if there is no food around, bacteria grow very slowly and do not need to divide very often. A good time for bacteria to divide is when plenty of their favorite foods, such as simple sugars, are available. In this situation, the bacterial cells will grow faster and will begin dividing very quickly, to make sure that as many new bacteria as possible are produced before the food runs out.
But the question is—how do the bacteria sense the presence of food in its environment and use this information to speed up growth and cell division? This is the question we wanted to answer in our study.
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