Introduction to Microbiology

Microbiology is simply defined as the study of microorganisms, with “micro” referring to the small and “biology” referring to the study of living things. The microbes studied vary widely, and the field of microbiology is divided into many subfields of research.

The field of microbiology is vital to humanity, not only because of the infectious diseases these microbes cause, but because “good” microbes are necessary for our survival on Earth. This field of study can be considered one of the most important areas of knowledge and research, considering that bacteria in and within our bodies outnumber our own cells.

type of microorganism

Microorganisms or “microbes” are small organisms. Most of these organisms are invisible to the naked eye, and we didn’t know how many of them until the invention of the microscope and the theory of bacteria.

Microbes can be found almost anywhere on the planet. They exist in the boiling pools of Yellowstone and in the deepest craters on the ocean floor. They can live in salt flats, and some thrive in salt water (so much use salt as a preservative). Some require oxygen to grow, others do not.

The world’s ‘hardest’ microbe is a species called Deinococcus radio transas the name suggests, the bacteria can withstand surprising levels of radiation, but can also survive without water, exposed to strong acids, or even placed in a vacuum.

Microorganisms in Microbiology

Scientists have many different ways of classifying and in doing so are trying to understand the millions of microbes among us.

Multicellular vs. Unicellular vs. Cellless

One of the ways microorganisms are classified is whether they have cells, and if so, how many. Microorganisms may be:

  • Multicellular: having multiple cells
  • Unicellular: There is one cell
  • Acellular: lacks cells, such as viruses and prions; prions are often referred to as “infectious proteins” rather than microorganisms.

Eukaryotes and Prokaryotes

Another way of classifying microorganisms is related to cell type. These include eukaryotes and prokaryotes:

  • Eukaryotes are microorganisms with “complex cells” with a true nucleus and membrane-bound organelles. Examples of eukaryotes include worms (worms), protozoa, algae, fungi, and yeast.
  • Prokaryotes are microorganisms with “simple cells” that have no true nucleus and lack membrane-bound organelles. Examples include bacteria.

Main categories of microorganisms

Different types of microorganisms can also be divided into:

  • Parasites: Parasites are sometimes scarier than other microbes, at least when they can be seen with the naked eye. Parasites include helminths (worms), flukes, protozoa, etc. Examples of parasitic infections include malaria, giardia and African sleeping sickness. Ascariasis (roundworm) is known to infect 1 billion people worldwide.
  • Fungi and Yeasts: Fungi are microorganisms that resemble plants in some ways. Yeast is a fungus. Examples include athlete’s foot or other types of yeast infections, both of which are fungal infections. This category also includes mushrooms and molds. Like bacteria, we also have many “good fungi” that live on our bodies and do not cause disease.
  • Bacteria: There are more bacteria in and within us than human cells, but the vast majority of these bacteria are “healthy bacteria.” They protect us from harmful or sick bacteria and play a role in digesting our food. Examples of infections caused by bacteria include tuberculosis and strep throat.
  • Viruses: Viruses are abundant in nature, but most people are familiar with those that cause disease in humans. Viruses can also infect other microorganisms, such as bacteria and plants. Immunization reduces the risk of some dire diseases, but others, such as Ebola and Zika, remind us that we haven’t begun to overcome these tiny threats.
  • Prions: Most scientists at this time do not classify prions as microorganisms, but as “infectious proteins.” That said, virologists often study them. Prions are essentially a piece of abnormally folded protein that may not be scary at first. However, prion diseases like mad cow disease are some of the most feared infectious diseases.
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History of Microbiology

What we now know about microbes (which will be discussed further) is relatively new in history. Let’s briefly review the history of microbiology:

First microscope/first visualization of microorganisms: Microbiology took an important step when Anthony van Leeuwenhoek (1632-1723) created the first single-lens microscope. By zooming in about 300 times, he was able to see bacteria (scraped from his teeth) for the first time.

Development of the germ theory: The human body was identified as the source of infection by three scientists:

  • Dr. Oliver Wendall Holmes found that women who gave birth at home were less likely to develop an infection than women who gave birth in a hospital.
  • Dr. Ignaz Semmelweis linked the infection to doctors who went straight from the autopsy room to the maternity ward without washing their hands.
  • Joseph Lister describes aseptic techniques, including hand washing and heat sterilization.

Bacteria Theory: Two of the most acclaimed recipients of the Bacteria Theory are Louis Pasteur and Robert Koch:

  • Louis Pasteur (1822-1895): Pasteur is considered a theory of biological origin, stating that all living things come from something, rather than the prevailing view when they arise spontaneously. He claimed that many diseases were caused by microorganisms. He proved that microbes were responsible for fermentation and spoilage, and developed a method called pasteurization, which is still used today. He also developed rabies and anthrax vaccines.
  • Robert Koch (1843-1910): Koch was the author of “The Koch Hypothesis,” a series of scientific steps in proving the theory of bacteria that has since been used in scientific research (with some revisions). He identified the causes of tuberculosis, anthrax and cholera.
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Since then, some landmarks have included the following:

  • 1892: Dmitri Iosifovich Ivanoski discovered the first virus.
  • 1928: Alexander Fleming discovered penicillin.
  • 1995: The first microbial genome sequence was published.

Infectious Microorganisms

When we think of microbes, most of us think of disease, although these little “bugs” are more likely to help us than hurt us overall. (Read further to learn about “good microbes.”)

Until less than a century ago, microbial infections are now the leading cause of death in many parts of the world. Life expectancy in the U.S. has risen significantly over the last century, not only because we are living longer, but mainly because fewer children die in childhood.

Heart disease and cancer are now the first and second leading causes of death in the United States. According to the World Health Organization, in low-income countries worldwide, the leading cause of death is lower respiratory tract infections, followed by diarrhoeal diseases.

The advent of vaccines and antibiotics, and more importantly, clean water, has lowered our fears about infectious organisms, but it is wrong to be arrogant. We are currently facing not only emerging infectious diseases, but also antibiotic resistance.

Microorganisms that are helpful to humans

Although we rarely talk about it, microbes are not only helpful but essential in almost every aspect of our lives. Microorganisms are important in:

  • Protect our bodies from ‘bad’ microbes
  • make food. From yogurt to alcoholic beverages, fermentation is a method of making food using the growth of microorganisms.
  • Decompose waste above ground and recycle atmospheric gases above. Bacteria can even help with difficult-to-treat waste, such as oil spills and nuclear waste.
  • Produces vitamins such as vitamin K and some B vitamins. Bacteria are also extremely important for digestion.
  • Information storage. The field of cryptography is even researching ways to use bacteria as hard drives for storing information.

Microbes not only perform many functions for We – they are part of us. It is believed that there are 10 to 1 more bacteria in our body and inside our body than our cells.

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You may have heard the latest on healthy eating. In addition to eating broccoli and blueberries, most health experts recommend eating fermented foods every day or at least as much as possible. Without bacteria, there is no fermentation.

Babies are born without bacteria. When they pass through the birth canal, they get their first bacteria. (A lack of exposure to bacteria through the birth canal is believed by some to be the reason why obesity and allergies are more common in babies born by caesarean section.)

If you’ve been reading the news lately, some even believe that the bacteria in our guts are responsible for our daily moods. The study of the microbiome is now being used to explain many things, such as why antibiotics may lead to weight gain.

field of microbiology

The field of microbiology has several distinct fields. Examples of some of these areas broken down by organism type include:

  • Parasitology: the biological study of parasites and parasitic diseases
  • Mycology: the study of fungi
  • Bacteriology: The study of bacteria
  • Virology: virus research
  • Protozoology: the study of protozoa
  • Phycology: The study of algae

The field of microbiology can also be broken down by scope, including a broad range of topics. Many examples include:

  • Microbial physiology (growth, metabolism and structure of microorganisms)
  • Microbial Genetics
  • Microbial evolution
  • Environmental Microbiology
  • Industrial Microbiology (eg, wastewater treatment)
  • Food Microbiology (Fermentation)
  • Biotechnology
  • bioremediation

The future of microbiology

The field of microbiology is fascinating, and there’s more that we don’t know. What we have learned most in the field is that there is still a lot to learn.

Not only can microorganisms cause disease, but they can also be used to develop drugs against other microorganisms (such as penicillin). Some viruses appear to cause cancer, while others are being evaluated as a way to fight cancer.

One of the most important reasons people study microbiology is to respect these “organisms” which are far more numerous than ours. Not only the inappropriate use of antibiotics, but also the inappropriate use of antibacterial soaps is thought to increase antibiotic resistance. This is just when looking at the microbes we currently know. With the advent of infectious diseases and our ability to travel almost anywhere in the world on three flights, there is a great need to educate and prepare microbiologists.