Search results
Results from the WOW.Com Content Network
A bacterial reference chart is used to determine the number of bacteria in the sample. Appropriate treatment is applied to the water source once abnormal levels of bacterial activity are noticed. Once water treatment is effective the bacterial count produced by the dip slide test should be low, approximately <10 4. [2]
Gram stain (Gram staining or Gram's method), is a method of staining used to classify bacterial species into two large groups: gram-positive bacteria and gram-negative bacteria. It may also be used to diagnose a fungal infection . [ 1 ]
A simple staining method for bacteria that is usually successful, even when the positive staining methods fail, is to use a negative stain. This can be achieved by smearing the sample onto the slide and then applying nigrosin (a black synthetic dye) or India ink (an aqueous suspension of carbon particles).
The specimen, such as a wet bacterial culture spread on a glass slide, is mixed with the negative stain and allowed to dry. When viewed with the microscope the bacterial cells, and perhaps their spores, appear light against the dark surrounding background. An alternative method has been developed using an ordinary waterproof marking pen to ...
Primarily, it has been shown that the distribution of bacterial cells on counting slides can be uneven and inconsistent. [22] In addition, to get a legitimate estimate of bacterial counts by using this technique, it has been suggested that more than 350 individual cells, from 20 fields of view must be measured. [ 22 ]
The acidity of the dyes causes them to bind more strongly to the cell walls of the bacteria than to other cells or tissues. This results in the selective staining of only those cells that have a high density of cell wall material, such as acid-fast bacteria. [27] The Ziehl-Neelsen stain is a two step staining process. In the first step, the ...
It is described using terms like brittle, creamy, sticky and dry. Staphylococci are considered to have a creamy consistency, [1]: 173 while some Neisseria species are sticky, and colonies of diphtheroid bacteria and beta-hemolytic streptococci are typically dry. [1]: 167–8 Bacteria that produce capsules often have a slimy (mucoid) consistency.
Bergey's Manual Trust was established in 1936 to sustain the publication of Bergey's Manual of Determinative Bacteriology and supplementary reference works. The Trust also recognizes individuals who have made outstanding contributions to bacterial taxonomy by presentation of the Bergey Award and Bergey Medal, jointly supported by funds from the Trust and from Springer, the publishers of the ...