Regulation of High-Temperature Stress Response by Small RNAs

Temperature extremes constitute one of the most common environmental stresses that adversely affect the growth and development of plants. Transcriptional regulation of temperature stress responses, particularly involving protein-coding gene networks, has been intensively studied in recent years. High-throughput sequencing technologies enabled the detection of a great number of small RNAs that have been found to change during and following temperature stress. The precise molecular action of some of these has been elucidated in detail. In the present chapter, we summarize the current understanding of small RNA-mediated modulation of high- temperature stress-regulatory pathways including basal stress responses, acclimation, and thermo-memory. We gather evidence that suggests that small RNA network changes, involving multiple upregulated and downregulated small RNAs, balance the trade-off between growth/development and stress responses, in order to ensure successful adaptation. We highlight specific characteristics of small RNA-based tem- perature stress regulation in crop plants. Finally, we explore the perspectives of the use of small RNAs in breeding to improve stress tolerance, which may be relevant for agriculture in the near future

A fast screening method for tricyclic antidepressants and their urinary metabolites by FAB-tandem mass spectrometry

Abstract. A screening method for tricyclic antidepressants (TCA) and their urinary metabolites by FAB tandem mass spectrometry (FAB MS/MS) is presented. The collision induced dissociation (CID) behavior of pure dibenzocycloheptadienes (amitriptyline 1, nortriptyline 2), dibenzoxepines (doxepine 3, dosulepine 4), dibenzazepines (imipramine 5, desipramine 6, trimipramine 7) and the iminostilbene derivative opipramol 8 is described and used for the specific determination of these tricyclics by MS/MS. For the screening procedure a methanolic extract of the urine sample is passed through a XAD-2 column and the eluate is examined without further purification after evaporation of the solvent. Identification of the TCA is achieved by constant neutral loss (CNL) scans for 173 u, 195 u and 193 u and subsequent daughter ion spectra of the molecular ions [M+H] + . Glucuronide conjugate metabolites of the tricyclic antidepressants 1, 2, 3, 6, 8 could be identified by CNL-scans (176 u) and the assignments were confirmed by daughter ion mass spectra. A urine sample of a fatal 1, 2, 8 overdose and samples of three patients under therapeutic dosage with 1, 3 or 6 are presented as examples for application

Molecular dynamics of poly(propylene) glycol in nanometer confinements

Dielectric spectroscopy and temperature modulated DSC are employed to study the molecular dynamics (dynamic glass transition) of oligomeric poly(propylene) glycol (PPG) melts (Mw=1000, 2000, 3000 and 5000) confined to nanoporous glasses (pore sizes 2.5, 5.0, 7.5 and 20 nm). For large pore sizes a speeding up of the molecular dynamic compared to the bulk state is observed which is already known for low molecular glass forming liquids. For smaller pore sizes the molecular dynamics is slower than in the bulk. The observed behavior is nearly independent of the molar mass and of the treatment of internal glass surfaces. The experimental results are discussed in the frame of an interplay of confinement and packing effects. Moreover a length scale of 1.5 nm is estimated as lower bound for the glass transition

Oxidized plant sterols in human serum and lipid infusions as measured by combined gas-liquid chromatography-mass spectrometry.

J Lipid Res 2001 Dec;42(12):2030-8 Related Articles, Books, LinkOut Oxidized plant sterols in human serum and lipid infusions as measured by combined gas-liquid chromatography-mass spectrometry. Plat J, Brzezinka H, Lutjohann D, Mensink RP, von Bergmann K. Maastricht University, Department of Human Biology, P.O. Box 616, 6200 MD, Maastricht, The Netherlands. [email protected] Some oxidized forms of cholesterol (oxysterols) are thought to be atherogenic and cytotoxic. Because plant sterols are structurally related to cholesterol, we examined whether oxidized plant sterols (oxyphytosterols) could be identified in human serum and soy-based lipid emulsions. We first prepared both deuterated and nondeuterated reference compounds. We then analyzed by gas-liquid chromatography-mass spectrometry the oxyphytosterol concentrations in serum from patients with phytosterolemia or cerebrotendinous xanthomatosis, in a pool serum and in two lipid emulsions. 7-Ketositosterol, 7 beta-hydroxysitosterol, 5 alpha, 6 alpha-epoxysitosterol, 3 beta,5 alpha,6 beta-sitostanetriol, and probably also 7 alpha-hydroxysitosterol were present in markedly elevated concentrations in serum from phytosterolemic patients only. Also, campesterol oxidation products such as 7 alpha-hydroxycampesterol and 7 beta-hydroxycampesterol were found. Interestingly, sitosterol was oxidized for approximately 1.4% in phytosterolemic serum, which is rather high compared with the approximate 0.01% oxidatively modified cholesterol normally seen in human serum. The same oxyphytosterols were also found in two lipid emulsions in which the ratio of oxidized sitosterol to sitosterol varied between 0.038 and 0.041.In conclusion, we have shown that oxidized forms of plant sterols are present in serum from phytosterolemic patients and two frequently used soy-based lipid emulsions. Currently, it is unknown whether oxyphytosterols affect health, as has been suggested for oxysterols. However, 7 beta-hydroxycholesterol may be one of the more harmful oxysterols, and both sitosterol and campesterol were oxidized into 7 beta-hydroxysitosterol and 7 beta-hydroxycampesterol. The relevance of these findings therefore deserves further exploration

Untersuchungen zur Biotransformation von Meclozin im menschlichen Körper

Peer Reviewe

Chemiluminescent determination of the pesticide bromoxynil by on-line photodegradation in a flow-injection assembly

[EN] A new, robust and simple method is proposed for the chemiluminescent determination of the pesticide Bromoxynil. The empirical procedure is performed with the aid of a flow-injection manifold provided with an on-line photo-reactor to obtain chemiluminescent photofragments. After a period of 12 s of irradiation with an 8 W low-pressure mercury lamp, a chemiluminescent oxidation was performed with the system potassium permanganate in a polyphosphoric acid medium. The photolysis required a basic medium (KOH 0.014 mol l(-1)) with ethanol (1%) as a sensitizer. The method allowed the determination of 134 samples h(-1) of Bromoxynil in a wide interval of concentrations, over the range 5 x 10(-3) - 1 mg l(-1); the detection limit was 5 x 10(-3) mg l(-1). The RSD (n = 24) at 0.25 mg l(-1) of the pesticide level was 2.3%. The method was applied to a water sample and to a formulation.This research was supported by Ministerio de Educación y Ciencia (Spanish Government), Project BQU2002-04248-C02-01.Pawlicova, Z.; Albert-Garcia, JR.; Sahuquillo, I.; García Mateo, JV.; Catalá-Icardo, M.; Martínez Calatayud, J. (2006). Chemiluminescent determination of the pesticide bromoxynil by on-line photodegradation in a flow-injection assembly. Analytical Sciences. 22(1):29-34. https://doi.org/10.2116/analsci.22.29S293422