MicroBiol MD2

• Microscopy allows us to view the very very small world of microbes, not all of them and not with as much detail as perhaps we would like, but the techniques are getting better.
• The size range we are talking about in microbiology is measured in micrometers and nanometers, with one micrometer being ten to the -6 meters and one nanometer being ten to the -9 meters.
• Bacteria and viruses typically fall between 10 to 1 micrometer in length, hence the need for special tools to view them.
• The largest viruses are in between the one micrometer and 100 nanometer scale, but they're certainly ones that are really really tiny closer to the 10 nanometer scale.
• Microscopes magnify making things bigger and you can play with the magnification depending on the instrument that you have and the collection of lenses that you have for that instrument.
• Electron microscopy provides high magnification (between 500,000 to 10 million times) and is used to see detailed structures like viruses.
• The resolution of a microscope determines how well the image is maintained, allowing for the distinction or detection of the difference or separation between two objects even when they're really really close together.
• Cryo electron microscopy is a newer technique that involves embedding samples in resin and cutting them thinly to obtain high-resolution images.
• Fluorescent microscopy uses different fluorescent dyes to highlight or label different parts of the cell or different proteins in the cell.
• Scanning electron microscopy provides a three-dimensional image of the sample, while transmission electron microscopy provides a two-dimensional cross-section image.
• Viruses are not visible under light microscopes due to their size falling between the wavelengths of light.
• Shorter wavelengths provide higher resolution and more detail.
• Staining techniques can be used to enhance contrast and detail in microscopy.
• Light microscopes can typically magnify up to a thousand times the size of something.
• Light microscopy allows for live observation of organisms in their natural environment.
• The resolution and detail of an image in microscopy is determined by the wavelength of the light source or electron beam used.
• The gram stain is a differential staining technique used to distinguish between gram-positive and gram-negative cells.
• As resolution diminishes as you magnify more and more, you start losing data points and the object itself gets really really fuzzy.
• All cells have a cell membrane and some cells have a cell wall.
• Some bacteria produce an additional external surface layer called a glycocalyx or a capsule or slime layer.
• The protective barrier is made of sticky polysaccharides and it protects the cells from drying out and allows them to attach to surfaces.
• Capsules are associated with pathogens because they allow the cells that can produce toxins and infection to physically remain attached to a surface like your lungs or somewhere where they're producing infection.
• The difference in morphology between cells that make a capsule and those that don't can be seen in the colonies produced by Mycobacterium, a bacterium that produces serious lung illness related to Mycobacterium tuberculosis.
• Frederick Griffith demonstrated in early experiments that DNA is the transforming particle by injecting mice with either rough or smooth Streptococcus pneumoniae bacteria and the smooth bacteria were the ones that produced disease in the mice and the rough did not.
• Some bacteria produce a protective structure for their DNA called a spore, which is similar to what plants produce as seeds and some fungi produce as spores.
• All cells have a cell membrane and some cells have a cell wall.
• The process of sporulation is triggered when the environmental conditions are not ideal, especially when there is moisture reduction or depletion of nutrients.
• Some bacteria produce an additional external surface layer called a glycocalyx or a capsule or slime layer.
• The samples used in the experiment were between 25 and 40 million years old.
• The protective barrier is made of sticky polysaccharides and it protects the cells from drying out and allows them to attach to surfaces.
• Some species of ocean bacteria produce gas vacuoles that aid in buoyancy.
• During sporulation, one of the copies of the chromosomes is moved to the pole of the cell where it is encased in a very thick protective layer of protein and the rest of the cell remains metabolically active, this part is called the vegetative cell.
• The new isolates fell in between the branches of the tree of bacteria where you would expect spore formers to be.
• The culture of yeast was worked on by a post-doc, Monika Baruchi, to examine how long spores remain viable.
• The spores were removed from the gut of these insects and cultured on plates, resulting in germination after a few days of incubation.
• The technique used in the experiment was rigorously demonstrated to be culturing what was retrieved from these ancient insects.
• Prokaryotic organisms tend to live in environments that are usually very low in nutrients and other important elements needed for cell division, growth, and metabolism.
• Bacteria store these nutrients in structures called inclusion bodies.
• Some inclusion bodies help cells store nutrients, while others aid in mobility.
• The intestines of animals are rich in these spores because they're all over the environment and whenever you eat something, you're actually bringing those in.