Spectral characterization of selected humic substances Enev, V., Brno University of Technology, Brno (Czech Republic). Materials Research Centre; Pospisilova, L., Mendel University in Brno (Czech Republic). Dept. of Agrochemistry, Soil Science, Microbiology and Plant Nutrition; Klucakova, M., Brno University of Technology, Brno (Czech Republic). Materials Research Centre ...
Soil and Water Research (Czech Republic),
01/2014, Letnik:
9, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Current concern for soil quality has stimulated research on soil organic matter (OM). Humic substances (HS) of different origin were compared applying ultraviolet-visible spectroscopy, Fourier ...transform infrared spectroscopy (FTIR), "steady-state" fluorescence spectroscopy, and 13C nuclear magnetic resonance (13C NMR). Sodium humates samples were isolated from soil (Gleyic Luvisol), compost, and South-Moravian lignite from the mine MÃr in Mikulèice. Sodium humates (SH) were extracted by a conventional procedure recommended by the International Humic Substances Society (IHSS). Results showed that the presence of O-containing functional groups (carbonyl in aldehydes and ketones, carboxyl in carboxylic acids, ester and ether groups) are in the order of compost - soil - lignohumate - lignite. Further, results of FTIR, fluorescence spectroscopy, and 13C NMR suggested that samples of sodium humates isolated from soil, compost, and lignite were a more polycondensed, oxidized, unsaturated, humified, and aromatic structure. On the other hand, commercial lignohumate (LH) had very simple structural components and wide molecular heterogeneity. Furthermore, a small molecular size and weight, low degree of aromatic polycondensation, low level of conjugated chromophores and fluorophores, and low humification degree were characteristic for commercial LH. It should be noted that the sample of commercial LH was characterized by 13C NMR analysis with a slightly higher value of aromaticity α in comparison with the sample of compost. The application of non-destructive analytical methods such as UV-VIS, FTIR, 13C NMR, and fluorescence spectroscopy help us to provide main characteristics of selected humic substances.
The chemical composition and structure of humic substances were established based on spectroscopic studies (EDXS, SRATR FTIR, and
13
C NMR). Humic acids were isolated from different matrices such as ...soils, compost, lignite, and commercial lignohumate. The btained results showed the highest content of aromatic groups in lignite and humic acids of Chernozem. The aromaticity degree (a) calculated from
13
C NMR spectroscopy data decreased in the following order: lignite > Chernozems > lignohumate > Luvisols > compost > Cambisols. Infrared spectroscopy detected bands indicative of aliphatic groups (C–H at 2925 cm
−1
); aromatic groups (C=C at 1620 cm
−1
); phenolic groups (at 1404–1419 cm
−1
); and carboxyl and carbonyl groups (at 1225–1223 cm
−1
) in all studied humic acid samples. The main differences were found in the fingerprint region of 1700–1000 cm
−1
. The reactivity of humic acids given by the O/R ratio showed that the highest amount of n-alkyl groups were in the lignohumate samples. EDX spectroscopy indicated elements occurring in situ. Soil humic acids contained Fe, Cu, Zn, Ti, Ca, K, S, P, Si, and Br.
The isomers and conformers of six push–pull enamines: 3-dimethylamino-, 3-methylamino- and 3-amino-2-acetyl propenenitrile (H
3C)
2N–CH
C(CN)(COCH
3), H
3C–NH–CH
C(CN)(COCH
3) and H
2N–CH
C(CN)(COCH
...3) and 3-dimethylamino-, 3-methylamino- and 3-amino-2-methylsulfonyl propenenitrile (H
3C)
2N–CH
C(CN)(SO
2CH
3), H
3C–NH–CH
C(CN)(SO
2CH
3) and H
2N–CH
C(CN)(SO
2CH
3) have been studied experimentally by vibrational and NMR spectroscopy and theoretically by the ab initio calculations at MP2 level in 6-31G** basis set. The IR and Raman spectra of all compounds as a solid and solute in various solvents have been recorded in the region 4000–50
cm
−1. The NMR spectra were obtained in chloroform and DMSO at room temperature.
All six compounds have been prepared by the same way. NMR spectra revealed that both dimethylamino compounds were prepared as a pure
E isomers whereas in the case of methylamino compounds the 3-methylamino-2-methylsulfonyl propenenitrile was prepared also as a pure
E isomer but 3-methylamino-2-acetyl propenenitrile as a pure
Z isomer. Also 3-amino-2-methylsulfonyl propenenitrile was obtained as a pure the
E isomer, but 3-amino-2-acetyl propenenitrile as a mixture of both
E and
Z isomers.
Confomational possibilities of studied compounds are given only by the rotation of the acetyl and methylamino groups. Vibrational spectra revealed existence of two conformers with
Z and
E orientation of acetyl group for 3-dimethylamino-2-acetyl propenenitrile. Two conformers with
anti or
syn orientation of methylamino group for 3-methylamino-2-methylsulfonyl propenenitrile have been confirmed by vibrational and NMR spectra, but only one conformer with
anti orientation of methylamino group for 3-methylamino-2-acetyl propenenitrile in chloroform solution and in solid phase was found. For latter compound the additional isomer/conformer was detected in more polar solvents (acetonitrile/DMSO). These experimental findings have been supported by ab initio solvent effect calculations.
Effects of creatine and vitamin E on muscle energetic metabolism, antioxidant stability and meat quality of pigs Lahucky, R., Slovenska Polnohospodarska Univ., Nitra (Slovak Republic). Katedra Specialnej Zootechniky; Bucko, O., Slovenska Polnohospodarska Univ., Nitra (Slovak Republic). Katedra Specialnej Zootechniky; Hascik, P., Slovenska Polnohospodarska Univ., Nitra (Slovak Republic). Katedra Hodnotenia a Spracovania Zivocisnych Produktov ...
Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis,
2012, Letnik:
60, Številka:
5
Journal Article
Recenzirano
Odprti dostop
The effects of supplementing the diet of pigs with creatine monohydrate (CMH) and vitamin E on blood plasma creatine concentration, vitamin E level in muscle, muscle energy metabolism, antioxidant ...capacity and meat (musculus longissimus dorsi) quality of pigs (DNA tested and negative on malignant hyperthermia) were investigated. Two treatments were used as follows: supplementation with CMH alone (2 g/kg of feed, 10 days before slaughter), supplementation with both vitamin E (500 mg alpha-tocopherol/kg of feed for minimum of 30 days) and CMH (2 g/kg of feed, 10 days before slaughter). Pigs supplemented with CMH alone showed significantly elevated plasma creatine concentration. Phosphorus nuclear magnetic resonance (31P NMR) measurements on post mortem (15 min.) muscle samples showed significantly higher phosphocreatine levels and ratio PCr/Pi in CMH supplemented pigs alone and in combination with vitamin E. Dietary supplementation with vitamin E significantly increased the concentration of alpha-tocopherol in meat. Supplementation with CMH alone or in combination with vitamin E resulted in higher (P = 0.07) a values of loin chops at 5 days of storage. Antioxidative capacity (measured as MDA production after incubation of longissimus muscle homogenates with Fe2+/ascorbate) was substantially improved by vitamin E and somewhat by CMH supplementation.
Twenty four crossbred (Large White, White Meaty, Pietrain, Hampshire) pigs were tested by DNA probe for a mutation on the ryanodine receptor RYR1 (malignant hyperthermia-MH). An equal number of pigs ...heterozygote (monomutant-MON) and normal on MH (nonmutant-NON) were used in the experiment. The pigs were fed finisher feed (control group) or finisher feed supplemented with magnesium (3.6 g MgO per pig per day; MgO group) for 5 days prior to slaughter. Pigs fed the diet supplemented with MgO had higher plasma Mg concentrations. Phosphorus nuclear magnetic resonance ((31)P NMR) measurements on postmortem (15 min) muscle samples (longissimus muscle) showed the highest phosphocreatine levels in normal pigs fed MgO (P<0.05). The MgO supplementation caused increased Ca(2+) uptake and Ca(2+) ATPase activity only in normal (NON) pigs. ATPase activity was lowest (P<0.05) in heterozygote control pigs. Pigs fed MgO supplemented diet had higher pH (45 min postmortem). A significant lower pH (P<0.05) was obtained in heterozygous (MON) control pigs. Also pigs fed with MgO had lower percentage of drip losses and significant differences (P<0.05) were obtained between heterozygous (MON) pigs. The results indicate that dietary MgO supplementation can improve parameters of muscle energetic metabolism, Ca(2+) uptake and meat quality (pH, drip loss).
Formation of the enolate of
iso-propyl phenyl acetate using phosphazene bases was studied by
1H,
13C and
31P NMR. It has been shown that: (i) while EtP2 was not strong enough, tBuP4 provided the ...enolate and (ii) only one isomer of the enolate was formed which was assigned the
Z-configuration from the stereo-outcome of the reaction. A strong conjugation between the phenyl ring and the enol moiety was observed (with Δ
G12 kcal/mol as estimated by NMR) and, in the absence of air/metals, the enol was stable until +40°C.
1H and
31P NMR studies of commercially available phosphazene bases have shown that EtP2 contained less than 5% of an undetermined P2 isomer and that tBuP4 contained up to 12% of another P4 isomer whose structure has been determined.
Graphic
Cyclohexadepsipetides enniatin B, B1 and G were isolated from the cultivation broth of Fusarium dimerum Penzig, an endophyte of Magnolia x soulangeana. Their production was about 350 mg l(-1) after ...96 h of submerged cultivation in Sabouraud maltose medium. Isolated enniatins inhibited growth of selected microorganisms and activity of 12-lipoxygenase with IC50 = 0.73 mg l(-1).
Multidrug resistance of murine leukaemic cell line L1210/VCR (obtained by adaptation of parental drug-sensitive L1210 cells to vincristine) is associated with overexpression of mdr1 gene product ...P-glycoprotein (Pgp)—the ATP-dependent drug efflux pump. 31P-NMR spectra of L1210 and L1210/VCR cells (the latter in the presence of vincristine) revealed, besides the decrease of ATP level, a considerable lower level of UDP-saccharides in L1210/VCR cells. Histochemical staining of negatively charged cell surface binding sites (mostly sialic acid) by ruthenium red (RR) revealed a compact layer of RR bound to the external coat of sensitive cells. In resistant cells cultivated in the absence or presence of vincristine, the RR layer is either reduced or absent. Consistently, resistant cells were found to be less sensitive to Concanavalin A (ConA). Moreover, differences in the amount and spectrum of glycoproteins interacting with ConA-Sepharose were demonstrated between sensitive and resistant cells. Finally, the content of glycogen in resistant cells is lower than in sensitive cells. All the above facts indicate that multidrug resistance of L1210/VCR cells mediated predominantly by drug efflux activity of Pgp is accompanied by a considerable depression of oligo- and/or polysaccharides biosynthesis.
The IR, Raman and NMR spectra of similar push–pull ethylenes 3-dimethylamino-2-acetyl propenenitrile (DAAPN) (H
3C)
2N–CH
C(CN)(COCH
3) and 3-dimethylamino-2-methylsulfonyl propenenitrile (DASPN) (H
...3C)
2N–CH
C(CN)(SO
2CH
3) were measured. According to NMR spectra both compounds were prepared as pure
E-isomers.
The observed IR and Raman bands were compared with harmonic vibrational frequencies, calculated using ab initio MP2 and B3LYP density functional methods in 6-31G** basis set, and assigned on the base of potential energy distribution. In addition, the geometries and relative energies of possible conformers and isomers of the studied compounds were also evaluated on the same levels.
Vibrational spectra revealed that in polar solutions E-DAAPN exists as two conformers with
Z or
E orientation of acetyl group, the
Z conformer being about 2.2±0.3
kJ
mol
−1 more stable than the
E one. The influence of environment polarity on this conformational equilibrium is discussed with respect to the SCRF solvent effect calculations using IPCM and PCM models.
The yellow pigment named neosartorin was isolated from the mycelium of
Neosartorya fischeri. Its structure representing an asymmetric ergochrome was deduced from spectral data
The yellow pigment, ...named neosartorin was isolated from the mycelium of
Neosartorya fischeri. Its structure, representing an asymmetric ergochrome, was deduced from spectral data, mainly NMR experiments.
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