Fagus sylvatica L. provenances maintain different leaf metabolic profiles and functional response

Most temperate forest tree species will suffer important environmental changes as result of the climate change. Adaptiveness to local conditions could change at different sites in the future. In this context, the study of intra-specific variability is important to clarify the singularity of different local populations. Phenotypic differentiation between three beech provenances covering a wide latitudinal range (Spain/ES, Germany/DE and Sweden/SE), was studied in a greenhouse experiment. Non-target leaf metabolite profiles and ecophysiological response was analyzed in well-watered and water stressed seedlings. There was a provenance-specific pattern in the relative concentrations of some leaf metabolites regardless watering treatment. The DE and SE from the center and north of the distribution area of the species showed a clear differentiation from the ES provenance in the relative concentration of some metabolites. Thus the ES provenance from the south maintained larger relative concentration of some organic and amino acids (e.g. fumaric and succinic acids or valine and isoleucine), and in some secondary metabolites (e.g. kaempferol, caffeic and ferulic acids). The ecophysiological response to mild water stress was similar among the three provenances as a consequence of the moderate water stress applied to seedlings, although leaf N isotope composition (δ¹⁵N) and leaf C:N ratio were higher and lower respectively in DE than in the other two provenances. This would suggest potential differences in the capacity to uptake and post-process nitrogen according to provenance. An important focus of the study was to address for the first time inter-provenance leaf metabolic diversity in beech from a non-targeted metabolic profiling approach that allowed differentiation of the three studied provenances.     

Biosynthesis of silver nanoparticles using Malva parviflora and their antifungal activity

Cheeseweed mallow (Malva parviflora L.) was used to biosynthesize silver nanoparticles. The biosynthesized silver nanoparticles were classified by UV–vis Spectroscopy and Fourier-Transform Infrared Spectroscopy (FT-IR). The shape and size distribution were visualized by Transmission Electron Microscopy (TEM), Field Emission Scanning Electron Microscopy (FE-SEM), and Zeta potential analysis. The chemical composition of M. parviflora leaf extract was identified by Gas Chromatography and Mass Spectroscopy (GC/MS). Finally, in vitro antifungal assay was done to assess the potential of biosynthesized silver nanoparticles and crude leaf extract of M. parviflora for inhibiting the mycelial growth of phytopathogenic fungi. The UV–vis analysis manifests the formation of silver nanoparticles. FTIR analysis established that chemicals of the leaf extract stabilized the biosynthesized silver nanoparticles by binding with the free silver ions. The TEM, FE-SEM and zeta potential analyzer confirmed that the biosynthesized silver nanoparticles were mostly spherical with an average diameter of 50.6 nm. The biosynthesized silver nanoparticles and leaf extract of M. parviflora effectively mitigate the mycelial growth of Helminthosporium rostratum, Fusarium solani, Fusarium oxysporum, and Alternaria alternata. The maximum reduction in mycelial growth by biosynthesized nanoparticles was observed against H. rostratum (88.6%). Whereas, the leaf extract of M. parviflora was most effective against F. solani (65.3%). Thus, the biosynthesis of nanoparticle assisted by M. parviflora is a feasible and eco-friendly method for the synthesis of silver nanoparticles. Further the silver nanoparticles and leaf extract of M. parviflora could be explored for the development of the fungicide.     

Role of Phytotoxins in Pine Wilt Diseases

Characteristic rapid death of pines after infection by Bursaphelenchus xylophilus suggests the involvement of phytotoxins in the pine wilt disease syndrome. Crude extract from diseased pine is toxic to pine seedlings, whereas an extract from healthy pine is not. The response of seedlings to the crude toxin is more prominent in susceptible pine species than in resistant ones. Benzoic acid, catechol, dihydroconiferyl alcohol, 8-hydroxycarvotanacetone (carvone hydrate), and 10-hydroxyverbenone, which are toxic, low molecular weight metabolites, can be isolated from diseased pines. Other unidentified toxins are also found. The toxicity of some of these metabolites correlates positively to the susceptibility of pines to B. xylophilus. Some of these abnormal metabolites show synergistic toxicity when in combination. The D-isomer of 8-hydroxycarvotanacetone, dihydroconiferylalcohol, and 10-hydroxyverbenone inhibited the reproduction of B. xylophilus. Cellulase excreted by pinewood nematode also may be involved in rapid wilting.     

Cellular fatty acids as chemical markers for differentiation of Yersinia pestis and Yersinia pseudotuberculosis

Aims:  Gas chromatography (GC) was utilized to investigate the cellular fatty acids (CFAs) composition of 141 Yersinia pestis isolates from different plague foci of China, and 20 Yersinia pseudotuberculosis strains as well.
Methods and Results:  The whole cell fatty acid methyl esters (FAMEs) were obtained by saponification, methylation and extraction followed with analysis using a standardized Microbial Identification System (MIS). Y. pestis and Y. pseudotuberculosis strains are quite similar in major CFA profiles, which include 16:0, 17:0 cyclo, 3-OH-14:0, 16:1ω7c and 18:1ω7c, accounting for more than 80% of the total CFAs.
Conclusions:  Yersinia pestis could be easily differentiated from Y. pseudotuberculosis by plotting the ratios of some CFA pairs, i.e.,14:0/18:0 vs 18:1ω7c/18:0, 3-OH-14:0/18:0 vs 18:1ω7c/18:0, 16:1ω7c/18:0 vs 18:1ω7c/18:0, 12:0/18:0 vs 18:1ω7c/18:0 and 12:0 ALDE/18:0 vs 16:1ω7c/18:0 fatty acids.
Significance and Impact of the Study:  In the present study, the normalized Sherlock MIS and Sherlock standard libraries were used to analyse the fatty acid composition of different strains of Y. pestis and Y. pseudotuberculosis . Meanwhile, ratios of certain CFA components were found to serve as chemical markers for differentiating the two closely related bacteria that are difficult to be differentiated by simply comparing CFA profiles based on other researches.     

Identification and Determination of Tele-Methylhistamine in Cerebrospinal Fluid by Gas Chromatography-Mass Spectrometry

Abstract: The presence of tele-methylhistamine in human cerebrospinal fluid has been established. The concentration was determined with the use of deuterated tele-methylhistamine. The preparation of the deuterated standard is described. The concentration range in samples from neuropsychiatric patients was 0.1-2.5 ng/ml. The structure of the pentafluoropropionyl derivative used for gas chromatography was studied with the aid of proton nuclear magnetic resonance spectroscopy.     

A method for measuring the lifetime of chemically and metabolically generated electrophilic species

A method is presented for the characterization of the reaction order and rate constant for chemically and metabolically generated reactive electrophilic intermediates. The procedure employs flow kinetics and trapping of the electrophilic species. Reactive agents or metabolic intermediates are passed through a column containing a bound nucleophilic reagent. The electrophilic species reacts at a characteristic rate while moving through the column at a fixed pH, temperature and rate of flow. The alkylation products formed during this reaction are quantified in individual column segments which correspond to time intervals. This provides data for the calculation of the lifetime of the short-lived species. The method may be used for agents having half-lives of 1 s to 30 min. Metabolic intermediates need not be isolated. Data is presented for the reaction rates of 1-methyl-1-nitrosourea (MNU), 1-methyl-3-nitro-1-nitrosoguanidine (MNNG) and iodomethane. A metabolic activation system is described for the conversion of acetoxymethylmethylnitrosamine (DMN-OAc) to hydroxymethylmethylnitrosamine (DMN-OH) and measurement of the stability of that intermediate. Hydroxymethylmethylnitrosamine was found to have a half-life of 28 s at pH 7.4, 37°C.     

Accurate micro- and macro- gas phase basicities of hydroxyl-radical-modified pyrimidines estimated by advanced quantum chemistry methods

The gas phase basicities (GPB) of 16 hydroxyl-radical-derived analogues of model pyrimidine nucleosides were analysed at B3LYP/aug-cc-pVDZ and G3MP2B3 levels of theory. All possible tautomeric equilibriums of neutral and protonated forms of pyrimidine analogues were taken into account. The oxidation of pyrimidines usually reduces the GPB values with respect to canonical values. The only exception was observed in the case of 5,6-dihydroxycytidine, which is more basic than model cytidine if both macro- and micro-scopic measures of basicities are used for comparison. In addition, 6-hydroxycytidine is characterised more by the basic character of the O₂ atom compared to the more basic centre of cytidine, despite the fact that the GPB values of both these compounds are almost identical. Although the B3LYP/aug-cc-pVDZ approach seems to be an accurate and robust method for GPB estimation, the microscopic protonation properties are much more sensitive to this method since the difference in energy between some tautomers is often less than 1 kcal/mol with method-dependent succession. In such cases, G3MP2B3 is recommended.     

The effect of rectal gas on dose distribution during prostate cancer treatment using full arc and partial arc Volumetric Modulated Arc Therapy (VMAT) treatment plans

Background/AimIn this study, we investigated the effect of rectal gas on the dose distribution of prostate cancer using a volumetric modulated arc therapy (VMAT) treatment planning.Materials and MethodsThe first is the original structure set, clinical target volume (CTV), the rectum, and the bladder used clinically. The second is a structure set (simulated gas structure set) in which the overlapping part of the rectum and PTV is overwritten with Hounsfield Unit −950 as gas. Full arc and limited gantry rotation angle with VMAT were the two arcs. The VMAT of the full arc was 181°–179° in the clockwise (CW) direction and 179°–181° in the counterclockwise (CCW) direction. Three partial arcs with a limited gantry rotation angle were created: 200°–160 °CW and 160°–200 °CCW; 220°–140 °CW and 140°–220 °CCW; and finally, 240°–120 °CW and 120°–240 °CCW. The evaluation items were dose difference, distance to agreement, and gamma analysis.ResultIn the CTV, the full arc was the treatment planning technique with the least effect of rectal gas. In the rectum, when the gantry rotation angle range was short, the pass rate tended to reduce for all evaluation indices. The bladder showed no characteristic change between the treatment planning techniques in any of the evaluation indices.ConclusionsThe VMAT treatment planning with the least effect on dose distribution caused by rectal gas was shown to be a full arc.     

Screening and characterization of endophytic fungi of Panax ginseng Meyer for biocontrol activity against ginseng pathogens

Forty endophytic fungi isolated from ginseng plants were screened to identify metabolites that had antifungal activity against ginseng microbial pathogens. The metabolites from the fungi were extracted from the liquid culture filtrates using ethyl acetate and then evaluated in vitro for antimicrobial activity against ginseng pathogens (Alternaria panax, Botrytis cinerea, Colletotrichum panacicola, Cylindrocarpon destructans, Rhizoctonia solani, and Phytophthora cactorum). Six of the fungi (Colletotrichum pisi, Fusarium oxysporum, Fusarium solani, Phoma terrestris, unknown 1 and 2) showed effective antimicrobial activity against all or some of the ginseng pathogens, with the extract of P. terrestris showing the strongest antimicrobial activity. The extract also showed inhibitory activity against spore germination of the pathogens. Gas chromatography–mass spectrometry (GC–MS) analysis of P. terrestris extract revealed that forty-one compounds were present in metabolites containing mainly N-amino-3-hydroxy-6-methoxyphthalimide (32% of the total metabolites) and 5H-dibenz [B, F] azepine (7%). Treatment with P. terrestris extract also caused morphological changes and reduced expression of the genes involved in mycelial growth and virulence. Treatment also induced defense-related genes in detached Arabidopsis leaves that were inoculated with the pathogens. These results indicate the antimicrobial potential for use of metabolites extracted from the ginseng endophytic fungi as alternatives to chemicals for biocontrol.