Bacteria communicate with each other in a population density-dependent process known as quorum sensing. N-acyl-homoserine lactones (HSLs) are the autoinducers of Gram-negative bacteria and the best-studied quorum sensing signals so far. HSLs induce various responses in plants, including systemic resistance and root development. Here, we used different methods, including tritium labelling, sensor strain assays and monoclonal antibodies (mAbs), to analyse the uptake and translocation of C8- and C10- homoserine lactones into barley (Hordeum vulgare cv Barke). Both HSLs were already systemically transported into the shoot at 2 h after application. HSL uptake could be inhibited by orthovanadate, demonstrating that ABC transporters are involved in the uptake. Root transport occurs predominantly via the central cylinder, which was shown by transport inhibition via KCl application and autoradiography of root cross-sections. Furthermore, a newly established detection method with mAbs allowed the first detection of a systemic transport of long-chain HSLs in plants. The coupled use of different HSL detection methods demonstrated that the uptake and transport of HSLs into barley does not occur passively, but relies, at least partially, on active processes in the plant.
- Klíčová slova
- N-acyl-homoserine lactones (HSLs), barley (Hordeum vulgare), monoclonal antibodies, quorum sensing, signalling,
- MeSH
- acylbutyrolaktony MeSH
- biologický transport MeSH
- ječmen (rod) metabolismus MeSH
- kořeny rostlin metabolismus MeSH
- quorum sensing MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- acylbutyrolaktony MeSH
- MeSH
- Archaea genetika metabolismus MeSH
- Bacteria genetika metabolismus MeSH
- chlor metabolismus MeSH
- houby genetika metabolismus MeSH
- mikrobiální společenstva fyziologie MeSH
- polymorfismus délky restrikčních fragmentů MeSH
- půda analýza MeSH
- půdní mikrobiologie * MeSH
- RNA ribozomální 16S analýza MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- chlor MeSH
- půda MeSH
- RNA ribozomální 16S MeSH
We studied the effect of increased inorganic chloride concentration on forest soil microflora in a laboratory experiment. Microbial DNA extracted from experimental soil samples was amplified with PCR using primer pairs specifically amplifying bacterial, eukaryotic and fungal DNA fragments. The resulting amplified DNA was further used for terminal restriction fragment length polymorphism (TRFLP) analysis. Our work revealed that chloride concentration affects the indigenous microbial community in experimental soil. This was documented on an unidentified microorganism whose DNA was detectable in soil high in chloride but was not found in soil with low chloride concentration. The presence of the organism responsive to increased chloride concentration was associated with the highest observed value of chlorination of humic acid, suggesting possible role of this organism in soil chlorine turnover. High chloride concentration in the soil tended to decrease the rate of degradation of trichloroacetic acid. The problems connected with measurement of chlorination rates in soil are discussed.
- MeSH
- chloridy toxicita MeSH
- DNA bakterií genetika MeSH
- DNA fungální genetika MeSH
- látky znečišťující půdu toxicita MeSH
- oxid uhličitý analýza MeSH
- počet mikrobiálních kolonií MeSH
- polymorfismus délky restrikčních fragmentů MeSH
- půda * analýza normy MeSH
- půdní mikrobiologie * normy MeSH
- radioizotopy uhlíku MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- chloridy MeSH
- DNA bakterií MeSH
- DNA fungální MeSH
- látky znečišťující půdu MeSH
- oxid uhličitý MeSH
- půda * MeSH
- radioizotopy uhlíku MeSH
Radioisotopes carbon 14 and chlorine 36 were used to elucidate the environmental role of trichloroacetic acid (TCA) formerly taken to be a herbicide and a secondary air pollutant with phytotoxic effects. However, use of 14C-labeling posed again known analytical problems, especially in TCA extraction from the sample matrix. Therefore--after evaluation of available methods--a new procedure using decarboxylation of [1,2-14C]TCA combined with extraction of the resultant 14C-chloroform with a non-polar solvent and its subsequent radiometric measurement was developed. The method solves previous difficulties and permits an easy determination of amounts between 0.4 and 20 kBq (10 - 500 ng g(-1)) of carrier-less [1,2-14C]TCA in samples from environmental investigations. The procedure is, however, not suitable for direct [36Cl]TCA determination in chlorination studies with 36Cl. Because TCA might be microbially degraded in soil during extraction and sample storage and its extraction from soil or needles is never complete, the decarboxylation method--i.e. 2 h TCA decomposition to chloroform and CO2 in aqueous solution or suspension in closed vial at 90 degrees C and pH 4.6 with subsequent CHCl3 extraction-is recommended here, estimated V < 7%. Moreover, the influence of pH and temperature on the decarboxylation of TCA in aqueous solution was studied in a broad range and its environmental relevance is shown in the case of TCA decarboxylation in spruce needles which takes place also at ambient temperatures and might amount more than 10-20% after a growing season. A study of TCA distribution in spruce needles after below-ground uptake shows the highest uptake rate into current needles which have, however, a lower TCA content than older needle-year classes, TCA biodegradation in forest soil leads predominatingly to CO2.
- MeSH
- chlor chemie MeSH
- chloroform chemie MeSH
- dekarboxylace MeSH
- ekosystém MeSH
- koncentrace vodíkových iontů MeSH
- kyselina trichloroctová analýza chemie metabolismus MeSH
- látky znečišťující půdu analýza MeSH
- monitorování životního prostředí metody MeSH
- nadzemní části rostlin chemie MeSH
- půda MeSH
- radioizotopy uhlíku chemie MeSH
- stromy MeSH
- teplota MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- chlor MeSH
- chloroform MeSH
- kyselina trichloroctová MeSH
- látky znečišťující půdu MeSH
- půda MeSH
- radioizotopy uhlíku MeSH
