Conky is not available for Mac but there are some alternatives that runs on macOS with similar functionality. The most popular Mac alternative is GKrellM, which is both free and Open Source. If that doesn't suit you, our users have ranked 19 alternatives to Conky and eight of them are available for Mac so hopefully you can find a suitable replacement. Conky is a system monitor for X originally based on torsmo. Since its inception, Conky has changed significantly from its predecessor, while maintaining simplicity and configurability. Conky can display just about anything, either on your root desktop or in its own window.
A MacConkey agar plate with an active bacterial culture.
MacConkey agar with LF and non-LF colonies
MacConkey agar is an indicator, a selective and differential culturemedium for bacteria designed to selectively isolate Gram-negative and enteric (normally found in the intestinal tract) bacilli and differentiate them based on lactosefermentation.[1] The crystal violet and bile salts inhibit the growth of Gram-positive organisms which allows for the selection and isolation of gram-negative bacteria. Enteric bacteria that have the ability to ferment lactose can be detected using the carbohydrate lactose, and the pH indicator neutral red.[2]
Contents[edit]
It contains bile salts (to inhibit most Gram-positive bacteria), crystal violet dye (which also inhibits certain Gram-positive bacteria), neutral red dye (which turns pink if the microbes are fermenting lactose).
Composition:[3]
There are many variations of MacConkey agar depending on the need. If the spreading or swarming of Proteus species is not required, sodium chloride is omitted. Crystal violet at a concentration of 0.0001% (0.001 g per litre) is included when needing to check if Gram-positive bacteria are inhibited. MacConkey with sorbitol is used to isolate E. coli O157, an entericpathogen.
History[edit]
The medium was developed by Alfred Theodore MacConkey while working as a bacteriologist for the Royal Commission on Sewage Disposal.
Uses[edit]
Using neutral red pH indicator, the agar distinguishes those Gram-negative bacteria that can ferment the sugar lactose (Lac+) from those that cannot (Lac-).
This medium is also known as an 'indicator medium' and a 'low selective medium'. Presence of bile salts inhibits swarming by Proteus species.
Lac positive[edit]
By utilizing the lactose available in the medium, Lac+ bacteria such as Escherichia coli, Enterobacter and Klebsiella will produce acid, which lowers the pH of the agar below 6.8 and results in the appearance of pink colonies. The bile salts precipitate in the immediate neighbourhood of the colony, causing the medium surrounding the colony to become hazy.[4][5]
Lac negative[edit]
Examples of non-lactose fermenting bacteria are Salmonella, Proteus species, Yersinia, Pseudomonas aeruginosa and Shigella.
Slow[edit]
Some organisms ferment lactose slowly or weakly, and are sometimes put in their own category. These include Serratia[6] and Citrobacter.[7]
Mucoid colonies[edit]
Some organisms, especially Klebsiella and Enterobacter, produce mucoid colonies which appear very moist and sticky. This phenomenon happens because the organism is producing a capsule, which is predominantly made from the lactose sugar in the agar.
Variant[edit]
A variant, sorbitol-MacConkey agar, (with the addition of additional selective agents) can assist in the isolation and differentiation of enterohemorrhagic E. coliserotypeE. coli O157:H7, by the presence of colorless circular colonies that are non-sorbitol fermenting.
See also[edit]
References[edit]
Retrieved from 'https://en.wikipedia.org/w/index.php?title=MacConkey_agar&oldid=941244856'
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