Flax (Linum usitatissimum L.) is grown for fiber and seed in many countries. Flax cultivars differ in the oil composition and, depending on the ratio of fatty acids, are used in pharmaceutical, food, ...or paint industries. It is known that genes of SAD (stearoyl-ACP desaturase) and FAD (fatty acid desaturase) families play a key role in the synthesis of fatty acids, and some alleles of these genes are associated with a certain composition of flax oil. However, data on genetic polymorphism of these genes are still insufficient.
On the basis of the collection of the Institute for Flax (Torzhok, Russia), we formed a representative set of 84 cultivars and lines reflecting the diversity of fatty acid composition of flax oil. An approach for the determination of full-length sequences of SAD1, SAD2, FAD2A, FAD2B, FAD3A, and FAD3B genes using the Illumina platform was developed and deep sequencing of the 6 genes in 84 flax samples was performed on MiSeq. The obtained high coverage (about 400x on average) enabled accurate assessment of polymorphisms in SAD1, SAD2, FAD2A, FAD2B, FAD3A, and FAD3B genes and evaluation of cultivar/line heterogeneity. The highest level of genetic diversity was observed for FAD3A and FAD3B genes - 91 and 62 polymorphisms respectively. Correlation analysis revealed associations between particular variants in SAD and FAD genes and predominantly those fatty acids whose conversion they catalyze: SAD - stearic and oleic acids, FAD2 - oleic and linoleic acids, FAD3 - linoleic and linolenic acids. All except one low-linolenic flax cultivars/lines contained both the substitution of tryptophan to stop codon in the FAD3A gene and histidine to tyrosine substitution in the FAD3B gene, while samples with only one of these polymorphisms had medium content of linolenic acid and cultivars/lines without them were high-linolenic.
Genetic polymorphism of SAD and FAD genes was evaluated in the collection of flax cultivars and lines with diverse oil composition, and associations between particular polymorphisms and the ratio of fatty acids were revealed. The achieved results are the basis for the development of marker-assisted selection and DNA-based certification of flax cultivars.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The recently introduced ion trap for FT-ICR mass spectrometers with dynamic harmonization showed the highest resolving power ever achieved both for ions with moderate masses 500–1000 Da (peptides) as ...well as ions with very high masses of up to 200 kDa (proteins). Such results were obtained for superconducting magnets of very high homogeneity of the magnetic field. For magnets with lower homogeneity, the time of transient duration would be smaller. In superconducting magnets used in FT-ICR mass spectrometry the inhomogeneity of the magnetic field in its axial direction prevails over the inhomogeneity in other directions and should be considered as the main factor influencing the synchronic motion of the ion cloud. The inhomogeneity leads to a dependence of the cyclotron frequency from the amplitude of axial oscillation in the potential well of the ion trap. As a consequence, ions in an ion cloud become dephased, which leads to signal attenuation and decrease in the resolving power. Ion cyclotron frequency is also affected by the radial component of the electric field. Hence, by appropriately adjusting the electric field one can compensate the inhomogeneity of the magnetic field and align the cyclotron frequency in the whole range of amplitudes of z-oscillations. A method of magnetic field inhomogeneity compensation in a dynamically harmonized FT-ICR cell is presented, based on adding of extra electrodes into the cell shaped in such a way that the averaged electric field created by these electrodes produces a counter force to the forces caused by the inhomogeneous magnetic field.
Lipidome atlas of the adult human brain Osetrova, Maria; Tkachev, Anna; Mair, Waltraud ...
Nature communications,
05/2024, Letnik:
15, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Lipids are the most abundant but poorly explored components of the human brain. Here, we present a lipidome map of the human brain comprising 75 regions, including 52 neocortical ones. The lipidome ...composition varies greatly among the brain regions, affecting 93% of the 419 analyzed lipids. These differences reflect the brain's structural characteristics, such as myelin content (345 lipids) and cell type composition (353 lipids), but also functional traits: functional connectivity (76 lipids) and information processing hierarchy (60 lipids). Combining lipid composition and mRNA expression data further enhances functional connectivity association. Biochemically, lipids linked with structural and functional brain features display distinct lipid class distribution, unsaturation extent, and prevalence of omega-3 and omega-6 fatty acid residues. We verified our conclusions by parallel analysis of three adult macaque brains, targeted analysis of 216 lipids, mass spectrometry imaging, and lipidome assessment of sorted murine neurons.
Resolving power of about 12,000 000 at
m/z
675 has been achieved on low field homogeneity 4.7 T magnet using a dynamically harmonized Fourier transform ion cyclotron resonance (FT ICR) cell. Mass ...spectra of the fine structure of the isotopic distribution of a peptide were obtained and strong discrimination of small intensity peaks was observed in case of resonance excitation of the ions of the whole isotopic cluster to the same cyclotron radius. The absence of some peaks from the mass spectra of the fine structure was explained basing on results of computer simulations showing strong ion cloud interactions, which cause the coalescence of peaks with
m/z
close to that of the highest magnitude peak. The way to prevent peak discrimination is to excite ion clouds of different
m/z
to different cyclotron radii, which was demonstrated and investigated both experimentally and by computer simulations.
Figure
ᅟ
Particle-in-Cell (PIC) ion trajectory calculations provide the most realistic simulation of Fourier transform ion cyclotron resonance (FT-ICR) experiments by efficient and accurate calculation of the ...forces acting on each ion in an ensemble (cloud), including Coulomb interactions (space charge), the electric field of the ICR trap electrodes, image charges on the trap electrodes, the magnetic field, and collisions with neutral gas molecules. It has been shown recently that ion cloud collective behavior is required to generate an FT-ICR signal and that two main phenomena influence mass resolution and dynamic range. The first is formation of an ellipsoidal ion cloud (termed “condensation”) at a critical ion number (density), which facilitates signal generation in an FT-ICR cell of arbitrary geometry because the condensed cloud behaves as a quasi-ion. The second phenomenon is peak coalescence. Ion resonances that are closely spaced in
m/z
coalesce into one resonance if the ion number (density) exceeds a threshold that depends on magnetic field strength, ion cyclotron radius, ion masses and mass difference, and ion initial spatial distribution. These two phenomena decrease dynamic range by rapid cloud dephasing at small ion density and by cloud coalescence at high ion density. Here, we use PIC simulations to quantitate the dependence of coalescence on each critical parameter. Transitions between independent and coalesced motion were observed in a series of the experiments that systematically varied ion number, magnetic field strength, ion radius, ion
m/z
, ion
m/z
difference, and ion initial spatial distribution (the present simulations begin from elliptically-shaped ion clouds with constant ion density distribution). Our simulations show that mass resolution is constant at a given magnetic field strength with increasing ion number until a critical value (N) is reached. N dependence on magnetic field strength, cyclotron radius, ion mass, and difference between ion masses was determined for two ion ensembles of different
m/z
, equal abundance, and equal cyclotron radius. We find that N and dynamic range depend quadratically on magnetic field strength in the range 1–21 Tesla. Dependences on cyclotron radius and Δ
m/z
are linear. N depends on
m/z
as (
m/z
)
–2
. Empirical expressions for mass resolution as a function of each of the experimental parameters are presented. Here, we provide the first exposition of the origin and extent of trade-off between FT-ICR MS dynamic range and mass resolution (defined not as line width, but as the separation between the most closely resolved masses).
Yields of liquid products (bio-oil and residual organics in aqueous solution) of hydrothermal liquefaction (at 300℃ and 60 min) of own cultivated Arthrospira platensis using different solvents have ...been determined. Nonpolar hexane, moderately polar dichloromethane, and relatively more polar acetonitrile have been used. High-resolution mass spectrometry based on linear quadrupole ion trap and Fourier transform mass spectrometer (LTQ FT) has been used for liquid sample characterization. Concentration of bio-oil in a unit of solvent volume after solvent extraction took the following arrangement: acetonitrile > dichloromethane > hexane. Concentration of residual organics in a unit of aqueous solution after solvent extraction took the following arrangement: hexane >dichloromethane > acetonitrile. Yield of total organics was arranged as follows: hexane > dichloromethane > acetonitrile. Content of carbon in bio-oil was increased and the content of oxygen was decreased with the increasing of solvent polarity. From mass spectrometric analysis it was established that in the positive electrospray ionization (ESI) mode the compounds containing two nitrogen atoms dominate and the considerable portion of the compounds containing single nitrogen atom are also presented for both bio-oil and residual organics samples. In the negative ESI mode the compounds containing four oxygen atoms dominated except bio-oil obtained using hexane where the compounds containing two oxygen atoms dominated. Bio-oil fraction had highly saturated compounds with low double bond equivalent values while the compounds of the residual organics fraction had large double bond equivalent values.
Understanding of behavior of ion ensembles inside FT-ICR cell based on the computer simulation of ion motion gives rise to the new ideas of cell designs. The recently introduced novel FT-ICR cell ...based on a Penning ion trap with specially shaped excitation and detection electrodes prevents distortion of ion cyclotron motion phases (normally caused by non-ideal electric trapping fields) by averaging the trapping DC electric field during the ion motion in the ICR cell. Detection times of 5 min resulting in resolving power close to 40,000,000 have been reached for reserpine at m/z 609 at a magnetic field of only 7 Tesla. Fine structures of resolved 13Cn isotopic cluster groups could be measured for molecular masses up to 5.7 kDa (insulin) with resolving power of 4,000,000 at 7 Tesla. Based on resolved fine structure patterns atomic compositions can be directly determined using a new developed algorithm for fine structure processing. Mass spectra of proteins and multimers of proteins reaching masses up to 186 kDa (enolase tetramer) could be measured with isotopic resolution. For instance, at 7 Tesla resolving power of 800,000 was achieved for enolase dimer (96 kDa) and 500,000 for molecular masses above 100 kDa. Experimental data indicate that there is practically no limit for the resolving power of this ICR cell except by collisional damping in the ultrahigh vacuum chamber.
This paper investigates a mainstream metal 3-D printing technique (i.e., direct metal laser sintering of stainless steel {SS} 316L) and two relatively new metal additive manufacturing methods (i.e., ...lost-wax casting of sterling silver using digital light projection/stereolithography-printed wax masters, and binder inkjet printing of SS 316L) for the fabrication, using tens-of-microns-sized voxels, of freeform, finely featured, mesoscaled metal structures part of compact systems. Characterization of the 3-D printing methods included assessment of dimensional accuracy and in-plane minimum feature size, measurement of vacuum outgassing, quantification of porosity, and estimation of thermal and electrical properties. The data demonstrate that binder inkjet printing of SS 316L has associated the smallest in-plane offset, out-of-plane offset, and eccentricity of nominally symmetric features while showing ultra-high-vacuum compatibility, low porosity, and intrinsic electrical and thermal properties close to those of bulk metal. Characterization of binder inkjet-printed SS 316L MEMS cantilevers shows repeatable micron-level linear actuation and a near-isotropic Young's modulus of the printed material close to the bulk value. Also, characterization in air at atmospheric pressure and room temperature of binder inkjet-printed SS 316L MEMS corona discharge ionizers with 32 high-aspect-ratio tips (25 tips/cm 2 , 5 mm tip height, 141.7 <inline-formula> <tex-math notation="LaTeX">\mu \text {m} \pm 3.2 ~\mu \text{m} </tex-math></inline-formula> tip radii) resulted in 8.7-kV start-up voltage and up to <inline-formula> <tex-math notation="LaTeX">422~\mu \text{A} </tex-math></inline-formula> total emission current; no evidence of tip degradation was found via optical inspection and device weighting after continuous IV characterization and a 12-h test (<inline-formula> <tex-math notation="LaTeX">300~\mu \text{A} </tex-math></inline-formula>, 13.5 kV). In addition, high-resolution microscopy of binder inkjet-printed SS 316L electrodes part of a novel, compact, multi-electrode harmonized Kingdon ion trap estimates at <inline-formula> <tex-math notation="LaTeX">\sim 15~\mu \text{m} </tex-math></inline-formula> the maximum height difference between the printed part and the digital model-making possible the implementation of portable, high-resolution mass spectrometers. 2018-0052
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