Viruses

Viruses are unique microbes in that they aren't really alive. They exist in two forms: a form outside the cell called the virion and a form inside the cell called a virus. A virus is the replicating form and only exists inside a cell. The virus hijacks the host cell machinary to make more virions. The virions are released from the cell to infect the next cell.

All viruses consists of protein and nucleic acid. Protein makes up the structure of the virus as well as aiding host cell hijacking. The nucleic acid is the genetic information of the cell. Like all cells, we humans have DNA as our genetic material. Since viruses are not cells, they are not bound by the DNA = genetic material law. Viral genomes can be made of RNA or DNA. The DNA or RNA can have a different structure than cells as well. In cells, DNA is double-stranded and RNA is single stranded. For viruses, the DNA or RNA can be double-stranded or single-stranded. Virologists use the nature of the nucleic acid to classify viruses.

A virus will use the protein component to enter host cells and hijack the host cell machinary using the nucleic acid as the directions to make more virions. The replication of the virus often has negative consequences on the host cell. The location of the host cell and the number of infected cells in turn has an affect on the host. The affect on the host is what produces the symptoms and consequences of a viral infectious disease. I'll illustrate this process with each virus we discuss.

Section 2 of Medical Microbiology describes virus structure, replication and pathogenesis in more detail.

What is Microbiology?

Day 1 of any microbiology course is a discussion of what is microbiology. The simple definition is "the study of microorganisms", but on further reflection, this definition really isn't all that simple. Two questions come from this definition: 1. what are microorganisms and how do we study them?

Microorganisms or microbes are organisms that can only be seen with a microscope. Thus, microbiology is the study of microscopic organisms. Well, sort of. Microbiologists study both cellular organisms like bacteria, algae, protozoa and fungi, but also acellular entities like viruses, prions and viroids. Since viruses are acellular and the cell is the basic unit of organisms, viruses are not organisms but they are microscopic.

The cellular organisms can be divided into two groups based on their structure: prokaryotes and eukaryotes. Bacteria are prokaryotes, while algae, protozoa and fungi are eukaryotes. Not all of the eukaryotes are microscopic. You have probably seen mushrooms growing in the woods or on your lawn for example. Microbiologists still claim fungi as part of their territory, however, since some fungal species are microscopic.

The Microbe World has a photo gallery of a few different types of microorganisms here, if you would like to put a picture to a name.

Since a microscope is necessary to see microorganisms, you are probably guessing that the microscope plays a big role in microbiology. For some microbiologists, yes, but for others no. In my graduate studies, the only time I saw I microscope was when I was teaching introductory microbiology courses. My research used molecular techniques to learn about how bacteria were resistant to antibiotics. There are numerous techniques used to study microbiology but the scientific method is the basis for all study. I will explain techniques as necessary in future blog posts.

An awesome introduction to microbiology is found in this video, "Initimate Strangers: The Unseen Life on Earth" Watch the first episode "The Microbial Universe" for more information on the scope of microbiology.

So as you can see, the definition of microbiology is just the beginning for a more complicated journey that I started 20 years ago and still feel like I have a lot to learn. I'm glad that you are sharing that journey with me.

It's Not a Course Unless There is a Textbook

If you are now having a flashback to your university days of standing in long lines and forking over huge sums of cash, relax. These textbooks are free online.

Todar's Online Textbook of Bacteriology - http://www.textbookofbacteriology.net/index.html

Medical Microbiology, 4th Edition by Samuel Baron - http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=mmed

Microbiology and Immunology Online from University of South Carolina Medical School - http://pathmicro.med.sc.edu/book/welcome.htm

The Very First Post - Ever

I created this blog several months ago and I've been waiting for the perfect blog entry to start things off. After months and months of waiting, I realize there is no perfect start and to just get on with it already. So, I'm taking the leap into the blogging fad.

My goal with this blog is to be an educational resource for parents about how microorganisms affect their kids from pregnancy to adulthood. I was inspired by several mommy boards in which participants asked some tough questions and got horrible, if not dangerous, information in response. A post on a message board is just not enough space to explain microbiology for the uninitiated, so here I am. If only one person finds this blog useful, I would say it is a success. I also have a selfish reason to write this blog as a means to develop my communication skills for an audience outside of academia.

I plan to start with the basics and then start addressing the more complex questions. A free basic microbiology course online combined with discussion if you will. There is enough gray areas in microbiology to make for very interesting discussions once the vocabulary is mastered and generating this type of discussion is another one of my goals. I learn a lot from my students and is one of my favourite things about my job as a university instructor.

I always welcome constructive criticism and questions for topics for discussion. I have set the comments to moderation just because I plan on dealing with some controversial topics and I've been attacked online before. This doesn't mean I'll censor anyone that disagrees with me. It means that I'll censor inappropriate comments that do not serve the educational purpose of this blog. Disagree in a respectful way, and I guarantee that your post will be approved. No name-calling and be sure to support your position with evidence.

I should also note that I'm not a medical doctor and have no clinical experience. I cannot diagnose or prescribe and the content of this blog should not be construed to be personal medical advice. If you have a concern about your child's health, take him/her to a real doctor.