Newer microscopy techniques and microscopes

Microscopy

As a beginning microbiology student, you will develop basic microscopy skills that have been used for years by a microbiologist.Put simple microscopy is the use of microscopes in all their various forms.Although you will perform most,if not all, of your examinations using bright field microscopy,it is possible to use the light microscope to perform different functions,such as bright brightfield,darkfield,fluorescence and phase contrast microscopy.Scientists continue to refine and develop light microscopy technique that performs additional specialized functions,such as measuring biochemical processes as they occur within living cells.

Newer microscopy techniques and microscopes

Since the development of the electron microscope,scientists have kept pushing microscopy to the limits of known technology.they have used computers,electronics and chemistry to improve the image they see and to understand cell activities at a molecular level.The following is a brief description of some of the more recent innovations; however,new discoveries are being reported with considerable frequency.Although some of this technology are currently being used primarily on eukaryotic cells , an additional application will include the study of prokaryotes.two of the newer light microscopy methods have added both cameras and computers to their lenses and light source.Video-enhanced contrast microscopy shows more details than ordinary light microscope because multiple images are captured on videotape.A computer that improves contrast by combining those images and subtracting the nonessential information also present in the specimen.Low-light dose microscopy uses weakly fluorescent marker dyes that attach to specimen parts of the cell,and a computer that enhances the fluorescent signals given off as biochemical processes take place in the cell.For example,if a chemical used as a marker fluoresces differently at different pH values, researchers can detect pH-changing metabolic activity inside cells.

A method called immunoelectron microscopy borrows some of the technology used in fluorescent antibody techniques.Antibodies attached to the particle of gold are mixed with cells; if they attach either to the cell surface or to other antibodies already fastened to cells,these gold particles appear as black dots within or on cells when to see through an electron microscope.By choosing specific antibiotics investigator can detect with structures within microorganisms are producing certain chemicals.This is because specific antibodies can bind to specific cell structures or to specific cell products such as certain enzymes.The technique can also distinguish dangerous types of a particular microorganism from those types that are less likely to cause diseases.For example,some candida Albicans types are more often associated with disease than others,and immunoelectron microscopy can differentiate between these two groups of yeast on the basis of the chemical they produce.

The scanning tunneling microscope also uses electrons rather than light,but they are used somewhat differently from those in TEM and SEM.An extremely sharp needle rides above the surface being scanned much like a photography needle on the record.Electrons moves between the measuring the current necessary to keep the needle,and researchers obtain an image by measuring the current necessary to keep the needle a constant height above the specimen.Rather than give the image of the whole microorganism or other material,this technology late individual atom on surfaces.Related to this microscope is the atomic force microscope,which applies a force between the needle and the surface.

Some of the latest microscopy techniques are neither electrons nor light waves.In 1988 scientists published the first image from a transmission positron microscope.Still experimental,this microscope uses a beam of positrons (atomic particles emitted by some radioactive material) rather than electrons to create an image.Also in 1988, researchers invented the microscope that shows the viewer moving the object while blocking the image of stationary objects a technique useful for finding motile microorganisms and debris.the microscope use laser light to produce hologram creating a trail as it is recorded.

Just as knowledge of microbiology has been applied to medicine,techniques now common in medicine are being adapted to microbiology.Now microbiologist performs microsurgery on cells,by using microscope equipped with micro-instruments to manipulate single cells.Image techniques used in hospital and medical clinics to take the picture of internal organs are being turned into microscopy tools.X-ray microtomography uses x-ray to produce three-dimensional images of objects that are only micrometers in size.However,the necessary concentration of X-ray kills living organisms, and so the technique is somewhat limited.Another technique that may be more promising is based on principles of magnetic resonance imagining,in which magnetic fields force electron in living tissue to shift position.When they return to their original location,computers help create image based on the patterns of energy they release.