Improved KCN Medium

Munson, Terry

doi:10.1128/aem.27.1.262-263.1974

Cited by 9 publications

(5 citation statements)

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“…considered to be cyanide resistant. Indeed, this property is often used as a taxonomic tool for differentiating this genus and other members of the family Enterobacteriaceae (14,19).…”

Section: Discussionmentioning

confidence: 99%

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Degradation of the metal-cyano complex tetracyanonickelate(II) by cyanide-utilizing bacterial isolates

Silva-Avalos

Richmond

Nagappan

et al. 1990

Appl Environ Microbiol

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Ten bacterial isolates capable of growth on tetracyanonickelate(II) {K2[Ni(CN)4]} (TCN) as the sole nitrogen source were isolated from soil, freshwater, and sewage sludge enrichments. Seven of the 10 were identified as pseudomonads, while the remaining 3 were classified as Klebsiella species. A detailed investigation of one isolate, Pseudomonas putida BCN3, revealed a rapid growth rate on TCN (generation time, 2 h), with substrate removal and growth occurring in parallel. In addition to TCN, all isolates were able to utilize KCN, although the latter was significantly more toxic; MICs ranged from 0.2 to 0.8 mM for KCN and .50 mM for TCN. While growth occurred over a wide range of TCN concentrations (0.25 to 16 mM), degradation was most substantial under growth-limiting conditions and did not occur when ammonia was present. In addition, cells grown on TCN were found to accumulate nickel cyanide [Ni(CN)21 as a major biodegradation product. The results show that bacteria capable of growth on TCN can readily be isolated and that degradation (i) appears to parallel the capacity for growth on KCN, (ii) does not occur in the presence of ammonia, and (iii) proceeds via the formation of Ni(CN)2 as a biological metabolite.

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“…considered to be cyanide resistant. Indeed, this property is often used as a taxonomic tool for differentiating this genus and other members of the family Enterobacteriaceae (14,19).…”

Section: Discussionmentioning

confidence: 99%

“…contrast, the CN-ligands in TCN are tightly bound to the central nickel atom and are thus unavailable to 2impart any toxicity; this fact is exemplified by the low disassociation (stability) constant of TCN (K, [IP]4[10][11][12][13][14][15][16][17][18][19][20][21][22] …”

mentioning

confidence: 99%

Degradation of the metal-cyano complex tetracyanonickelate(II) by cyanide-utilizing bacterial isolates

Silva-Avalos

Richmond

Nagappan

et al. 1990

Appl Environ Microbiol

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“…Many microbiologists have noted the value of tetrazolium salts as indicators of viability (Postgate 1967;Bartlett et al 1976;Urban and Jarstrand 1979;Zimmerman et al 1978;Tabor and Neihof 1982;Roszaak and Colwell 1987). These reagents have also been used for specific staining (Sedar and Burde 1965; Leene and van Iterson 1965) and biochemical reactions (Barer et al 1990;Cesari et al 1969), and as components of culture media (MacFaddin 1982;Munson 1974;Slanetz and Bartley 1957). In spite of this widespread use, microbiological studies have largely ignored the substantial body of information on the in situ chemistry of tetrazolium reactions (Altman 1976;Horobin 1982;Seidler 1991) which has underpinned their application in the demonstration and quantitation of specific enzyme activities at explicit tissue locations (Lojda et al 1979;Rost 1980;Van Noorden and Jonges 1987).…”

Section: Introductionmentioning

confidence: 99%

Factors affecting the selection and use of tetrazolium salts as cytochemical indicators of microbial viability and activity

Thom

Horobin

Seidler³

et al. 1993

Journal of Applied Bacteriology

119

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The reduction of four tetrazolium cations (TCs), nitroblue tetrazolium (NBT), neotetrazolium (NT), methylthiazolyldiphenyltetrazolium (MTT) and iodonitrophenyltetrazolium (INT), by viable micro-organisms, immobilized on glass cover slips, was examined by light microscopy with a view to determining a systematic basis for applying these reagents as cytochemical indicators of microbial viability and activity. The potential value of histochemical information about TC reactions for developing their microbiological applications was also assessed. INT and MTT detected viable cells more readily than NBT and NT. In order to obtain cell-localized formazan, MTT required cobalt ions in the reaction mixture and INT reactions had to be assessed soon after mounting. In general, formazan deposition could be accelerated by the addition of glucose and an intermediate electron carrier (IEC) to the reaction mixture, although inhibitory effects of IECs were also detected. Cultures in exponential phase, in stationary phase and inhibited by chloramphenicol could be differentiated with MTT but not with INT. For some organisms, notably Candida albicans, Pseudomonas aeruginosa and Enterococcus faecalis. TC reactions proved to be a relatively insensitive means of demonstrating viability. Two parameters used in selecting TCs for histochemical reactions, lipophilicity and reducibility appeared to be predictive for the relative sensitivity of these reagents as indicators of cell viability. The concepts of substantivity, a measure of non-specific interactions between reagents and staining substrates, and TC oxygen sensitivity, the effect of competition between oxygen and TCs for electrons, were found to be relevant to formazan deposition in live microbes. These findings support the use of TCs as cytochemical probes of microbial activity in defined settings and the use of histochemical knowledge to support further development of these techniques.

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“…Differentiation between cyanide-sensitive and cyanide-resistant organisms has been used as a taxonomic test. Moller developed a cyanide-containing medium (116), which has been improved by inclusion ofan indicator (56) and a higher concentration of cyanide (119). It has been shown that the Enterobacteriaceae can be subdivided into cyanide-sensitive (Escherichia, Shigella, Edwardsiella, Salmonella, Arizona) and cyanide-resistant (Citrobacter, Klebsiella, Enterobacter, Serratia, Proteus, Providencia, Aeromonas) species (79,119).…”

Section: Mechanisms Of Cyanide Resist-ance and Detoxicationmentioning

confidence: 99%