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ZweetbacteriŽn


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#1

Sfekky

    Sfekky


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Geplaatst op 17 juli 2008 - 13:17

Zweet op zich reukt niet, de geur is het gevolg van de aanwezigheid van bacteriŽn.
Ik ben op zoek naar welke bacteriŽn verantwoordelijk zijn voor de geur van zweet en eventueel welk mechanisme (productie van bepaalde stoffen,... ?) hiervoor verantwoordeijk zijn. Kan iemand me hiermee helpen?
Alvast bdankt

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#2

anusthesist

    anusthesist


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Geplaatst op 17 juli 2008 - 20:17

Zweet op zich reukt niet, de geur is het gevolg van de aanwezigheid van bacteriŽn.
Ik ben op zoek naar welke bacteriŽn verantwoordelijk zijn voor de geur van zweet en eventueel welk mechanisme (productie van bepaalde stoffen,... ?) hiervoor verantwoordeijk zijn. Kan iemand me hiermee helpen?
Alvast bdankt


Identification of odoriferous sulfanylalkanols in human axilla secretions and their formation through cleavage of cysteine precursors by a C-S lyase isolated from axilla bacteria.
Natsch A, Schmid J, Flachsmann F.

Givaudan Schweiz AG, Ueberlandstrasse 138, CH-8600 Duebendorf. andreas.natsch@givaudan.com


Human axillary odor is known to be formed upon the action of Corynebacteria sp. on per se odorless axilla secretions. Besides the known odoriferous acids, we report the occurrence in human axilla secretions of four odoriferous sulfanylalkanols, namely 3-sulfanylhexan-1-ol (3), 2-methyl-3-sulfanylbutan-1-ol (4), 3-sulfanylpentan-1-ol (5), and 3-methyl-3-sulfanylhexan-1-ol (6). These compounds have a pungent sweat/kitchen odor, also reminiscent of onions with some fruity connotations, and perception thresholds in the pg/l range. It was postulated that the odorless precursors for these compounds are cysteine conjugates. Bacterial isolates obtained from the human axilla and belonging to the Corynebacteria were, indeed, found to have the enzymatic capacity to release various thiols from cysteine conjugates. The metC gene, which is known to code for a cystathione-beta-lyase, was cloned from the axilla isolate Corynebacterium striatum Ax20 and heterologously expressed in E. coli. The pure recombinant enzyme cleaves various cysteine conjugates and has a similar substrate specificity as the cell homogenates of the wild-type. The recombinant enzyme was finally incubated with odorless axilla secretions and shown to release odoriferous thiols.


3-Methyl-3-sulfanylhexan-1-ol as a major descriptor for the human axilla-sweat odour profile.
Troccaz M, Starkenmann C, Niclass Y, van de Waal M, Clark AJ.


Firmenich SA, Corporate R&D Division, P.O. Box 239, CH-1211 Geneva 8.


This study sets out to redress the lack of knowledge in the area of volatile sulfur compounds (VSCs) in axillary sweat malodour. Sterile odourless underarm sweat (500 ml) was collected from 30 male volunteers after excessive sweating. Five strains of bacteria, Corynebacterium tuberculostearicum, Corynebacterium minutissimum, Staphylococcus epidermidis, Staphylococcus haemolyticus, and Bacillus licheniformis, were isolated and characterised for their ability to generate an authentic axillary odour from the sweat material collected. As expected, all of the five bacterial strains produced strong sweat odours. Surprisingly, after extensive olfactive evaluation, the strain of Staphylococcus haemolyticus produced the most sulfury sweat character. This strain was then chosen as the change agent for the 500 ml of odourless underarm sweat collected. After bacterial incubation, the 500-ml sample was further processed for GC-olfactometry (GC-O), GC/MS analysis. GC-O of an extract free of organic acids provided three zones of interest. The first was chicken-sulfury, the second zone was onion-like, and the third zone was sweat, clary sage-like. From the third zone, a new impact molecule, ®- or (S)-3-methyl-3-sulfanylhexan-1-ol, was isolated and identified by GC/MS, MD-GC, and GC AED (atomic emission detector). (S)-3-methyl-3-sulfanylhexan-1-ol was sniff-evaluated upon elution from a chiral GC column and was described as sweat and onion-like; its opposite enantiomer, ®-3-methyl-3-sulfanylhexan-1-ol, was described as fruity and grapefruit-like. The (S)-form was found to be the major enantiomer (75%).
That which can be asserted without evidence can be dismissed without evidence.





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