Microbiology is a broad term which includes virology, mycology, parasitology, bacteriology, immunology and other branches. A microbiologist is a specialist in microbiology and these related topics.
Microbiological procedures usually must be aseptic, and use a variety of tools such as light microscopes with a combination of stains and dyes.The most commonly used stains are called basic dyes, and are composed of positively charged molecules. Two types of basic dyes are simple stains and differential stains. Simple stains consist of one dye and identify the shape and multicell arrangement of bacteria. Methylene blue, carbolfuchsin, safranin, and crystal violet are some of the most commonly used stains. Differential stains on the other hand, use two or more dyes and help us to distinguish between two or more organisms or two or different parts of the organism. Types of differential stains are gram, Ziehl-Neelsen acid fast, negative, flagella, and endospore. Specific constraints apply to particular fields of microbiology, such as parasitology, which heavily utilizes the light microscopy, whereas microscopy's utility in bacteriology is limited due to the similarity is many cells physiology. Indeed, most means of differentiating bacteria is based on growth or biochemical reactions. Virology has very little need for light microscopes, relying on almost entirely molecular means. Mycology relies on all technologies the most evenly, from macroscopy to molecular techniques.
And a new study suggests that naturally occurring bacteria on the skin of salamanders could help protect other amphibians, including some species of endangered frogs, from a lethal skin disease. The researchers from James Madison University, Harrisonburg, Virginia and Vanderbilt University, Nashville, Tennessee report their findings in the November 2009 issue of the journal Applied and Environmental Microbiology.
Batrachochytrium dendrobatidis is a fungal pathogen that can cause a lethal skin disease in amphibians, however, some species remain relatively symptom free during infection. Innate immune factors, antimicrobial peptides, skin-associated microbial species, and behavior are all believed to attribute to the survival of some species over others. Researchers have found antifungal microbes to be of particular interest because their presence suggests they are mutualistic associates of amphibian species, meaning that there is a mutually beneficial relationship between the two organisms.
In a prior study Janthinobacterium lividum was identified as a bacterium that produces the anti-B. dendrobatidis metabolite violacein. Violacien was found on three of seven wild-collected red-backed salamanders (Plethodon cinereus) at concentration levels capable of inhibiting B. dendrobatidis, indicating a mutualistic community of violacein-producing bacteria. In this study researchers added J. lividum to the same species of red-backed salamanders and then exposed them to B. dendrobatidis. Results showed that adding J. lividum to the skin of the salamander increased the concentration levels of violacein already present and contributed to survival following experimental exposure to the fungus.
