Lighting conditions are an important controller of plant growth and development, and they affect secondary metabolite synthesis. In this research, we explored the effect of additional UV irradiation ...of various ranges in addition to the main one at PPFD 160 µmol m−2 s−1 on the accumulation of some secondary metabolites of stevia (Stevia rebaudiana Bertoni). The fresh weight of leaves was slightly higher under additional UV-A and UV-B irradiation compared with the control variant, and the leaf surface area was significantly larger, respectively, by 23.3 and 20.7% than in the control variant, while the rate of photosynthesis did not decrease. Plants under additional UV-B and UV-C irradiation were under the greatest light stress, as evidenced by a decrease in antioxidant capacity by an average of 30% compared to the control and UV-A. The total flavonoid content was significantly higher (by 74%) under UV-B irradiation. The highest concentration of steviol glycoside was observed during budding and flowering under UV-B and UV-C irradiation (by 13.2 and 11.3%, respectively). Analysis of hyperspectral images, chlorophyll fluorescence, and vegetation indices showed light stress increasing under UV-C irradiation, which caused an increase in the relative chlorophyll content, scorches, leaf morphology changes, a CO2 absorption rate decrease, and plant growth inhibition. UV-B irradiation can be used as an optimal type of irradiation based on a set of indicators.
Apart from energy transformation, mitochondria play important signaling roles. In yeast, mitochondrial signaling relies on several molecular cascades. However, it is not clear how a cell detects a ...particular mitochondrial malfunction. The problem is that there are many possible manifestations of mitochondrial dysfunction. For example, exposure to the specific antibiotics can either decrease (inhibitors of respiratory chain) or increase (inhibitors of ATP-synthase) mitochondrial transmembrane potential. Moreover, even in the absence of the dysfunctions, a cell needs feedback from mitochondria to coordinate mitochondrial biogenesis and/or removal by mitophagy during the division cycle. To cope with the complexity, only a limited set of compounds is monitored by yeast cells to estimate mitochondrial functionality. The known examples of such compounds are ATP, reactive oxygen species, intermediates of amino acids synthesis, short peptides, Fe-S clusters and heme, and also the precursor proteins which fail to be imported by mitochondria. On one hand, the levels of these molecules depend not only on mitochondria. On the other hand, these substances are recognized by the cytosolic sensors which transmit the signals to the nucleus leading to general, as opposed to mitochondria-specific, transcriptional response. Therefore, we argue that both ways of mitochondria-to-nucleus communication in yeast are mostly (if not completely) unspecific, are mediated by the cytosolic signaling machinery and strongly depend on cellular metabolic state.
The acid-catalyzed condensation between 2-aminosubstituted 1,2,4triazolo1,5-apyrimidines and their analogues with various saturation of the pyrimidine ring and 1,3-diketones or ...1,1,3,3-tetramethoxypropane was evaluated as a new approach for the synthesis of diversely substituted polycyclic derivatives of triazolopyrimidine. The reaction of 4,5,6,7-tetrahydro- or aromatic aminotriazolopyrimidines results in selective formation of the corresponding 1,2,4triazolo1,5-a:4,3-a′dipyrimidin-5-ium salts, and the condensation of substrates containing the 4,7-dihydro-1,2,4triazolo1,5-apyrimidine fragment is accompanied by a cascade rearrangement with unusual recyclization of the dihydropyrimidine ring to yield partially hydrogenated 1,2,4triazolo1,5-a:4,3-a′dipyrimidin-5-ium or pyrimido1′,2′:1,51,2,4triazolo3,4-bquinazolin-5-ium salts. The proposed methodology exhibits a wide scope, providing rapid access to polycondensed derivatives of the 1,2,4triazolo1,5-apyrimidine scaffold. DFT calculations of the Gibbs free energies of possible isomers were performed to rationalize the experimentally observed reactivity and selectivity.
•Clonal yeast populations are extremely heterogeneous in mitochondrial network structure.•AAC2 repression increases mitochondrial ΔΨ and induces mitochondrial fragmentation.•AAC2 repression prevents ...further protonophore-induced mitochondrial fragmentation.•AAC2 is dispensable for mitochondrial fusion in yeast.
The mitochondrial network structure dynamically adapts to cellular metabolic challenges. Mitochondrial depolarisation, particularly, induces fragmentation of the network. This fragmentation may be a result of either a direct regulation of the mitochondrial fusion machinery by transmembrane potential or an indirect effect of metabolic remodelling. Activities of ATP synthase and adenine nucleotide translocator (ANT) link the mitochondrial transmembrane potential with the cytosolic NTP/NDP ratio. Given that mitochondrial fusion requires cytosolic GTP, a decrease in the NTP/NDP ratio might also account for protonophore-induced mitochondrial fragmentation. For evaluating the contributions of direct and indirect mechanisms to mitochondrial remodelling, we assessed the morphology of the mitochondrial network in yeast cells with inhibited ANT. We showed that the repression of AAC2 (PET9), a major ANT gene in yeast, increases mitochondrial transmembrane potential. However, the mitochondrial network in this strain was fragmented. Meanwhile, AAC2 repression did not prevent mitochondrial fusion in zygotes; nor did it inhibit mitochondrial hyperfusion induced by Dnm1p inhibitor mdivi-1. These results suggest that the inhibition of ANT, rather than preventing mitochondrial fusion, facilitates mitochondrial fission. The protonophores were not able to induce additional mitochondrial fragmentation in an AAC2-repressed strain and in yeast cells with inhibited ATP synthase. Importantly, treatment with the ATP synthase inhibitor oligomycin A also induced mitochondrial fragmentation and hyperpolarization. Taken together, our data suggest that ATP/ADP translocation plays a crucial role in shaping of the mitochondrial network and exemplify that an increase in mitochondrial membrane potential does not necessarily oppose mitochondrial fragmentation.
Chemicals inducing a mild decrease in the ATP/ADP ratio are considered as caloric restriction mimetics as well as treatments against obesity. Screening for such chemicals in animal model systems ...requires a lot of time and labor. Here, we present a system for the rapid screening of non-toxic substances causing such a de-energization of cells. We looked for chemicals allowing the growth of yeast lacking trehalose phosphate synthase on a non-fermentable carbon source in the presence of glucose. Under such conditions, the cells cannot grow because the cellular phosphate is mostly being used to phosphorylate the sugars in upper glycolysis, while the biosynthesis of bisphosphoglycerate is blocked. We reasoned that by decreasing the ATP/ADP ratio, one might prevent the phosphorylation of the sugars and also boost bisphosphoglycerate synthesis by providing the substrate, i.e., inorganic phosphate. We confirmed that a complete inhibition of oxidative phosphorylation alleviates the block. As our system includes a non-fermentable carbon source, only the chemicals that did not cause a complete block of mitochondrial ATP synthesis allowed the initial depletion of glucose followed by respiratory growth. Using this system, we found two novel compounds, dodecylmethyl diphenylamine (FS1) and diethyl (tetradecyl) phenyl ammonium bromide (Kor105), which possess a mild membrane-depolarizing activity.
Sterols change the biophysical properties of lipid membranes. Here, we analyzed how sterols affect the activity of widely used antimicrobial membrane-active compounds, sodium dodecyl sulfate (SDS) ...and benzalkonium chloride (BAC). We also tested a novel benzalkonium-like substance, Kor105. Our data suggest that benzalkonium and Kor105 disturb the ordering of the membrane lipid packaging, and this disturbance is dampened by cholesterol. The disturbance induced by Kor105 is stronger than that induced by BAC because of the higher rigidity of the Kor105 molecule due to a shorter linker between the phenyl group and quaternary nitrogen. On the contrary, individual SDS molecules do not cause the disturbance. Thus, in the tested range of concentrations, SDS-membrane interaction is not influenced by cholesterol. To study how sterols influence the biological effects of these chemicals, we used yeast strains lacking Lam1-4 proteins. These proteins transport sterols from the plasma membrane into the endoplasmic reticulum. We found that the mutants are resistant to BAC and Kor105 but hypersensitive to SDS. Together, our findings show that sterols influence the interaction of SDS versus benzalkonium chloride and Kor105 with the membranes in a completely different manner.
Purpose
Accounting for ionic strength and ion association, the degree of calculated supersaturation with CaCO
3
of gleyic solonetz and molic solonetz soil solution is high. The purpose of the ...research was to reveal the effect of the water-dissolved organic matter (DOM) on the calcium carbonate equilibrium (CCE) in soil solution, to create a thermodynamic model of carbonate association and complexation with DOM and heavy metals (HMs), and to correct the principal of soil management.
Materials and methods
Object of research—Kastanozem complex of the dry steppe, Rostov Oblast, Russia. The water extraction of soluble salts was made at the water-to soil-ratio 5:1 and analyzed using standard methods. DOM content was determined by Strosser (J Agrobiol 27:49–60,
2010
). The soil solution macro-ion equilibrium composition was calculated using ION-2 program (Endovitsky et al.
2009
). DOM role in soil solution supersaturation with СаСО
3
was assessed, comparing C content in real solution and in identical artificial solution prepared without organic matter. Taking into account the ion association, the molar fractions of free and bound HM ion were calculated using microelement association coefficient,
k
as(ME)
. The soil liquid-phase saturation with CaCO
3
was characterized by the ratio of the real solubility product (
S
) to the thermodynamic solubility product (
S
0
):
К
=
S
/
S
0
.
Results and discussion
The soil solution supersaturation with CaCO
3
was characterized by the product of analytical concentrations (
S
), equilibrium concentrations accounting ion activity (
S
I
), ion association (
S
II
), ion association and complexation (
S
III
), and the thermodynamic solubility product (
S
0
). To evaluate the role of DOM in soil solution supersaturation with CaCO
3
, the initial pure Ca (HCO
3
)
2
solution series was prepared. The humic and fulvic acids from the illuvial horizon of gleyic solonetz with concentrations of 20 mg C L
−1
and 120 mg C L
−1
decreased the CaCO
3
precipitation compared with initial soil solution. The release of CaCO
3
from soil water extracts containing water-soluble organic matter was 1.2–1.9 times less compared with identical artificial solution not containing organic matter. The HM binding by carbonates is proportional to the DOM content.
Conclusions
In molic solonetz and gleyic solonetz, the neutralization of the soda should be assessed by the soil solution supersaturation with CaCO
3
. To calculate the degree of HM passivation in soil solution containing DOM, the coefficient of soil solution oversaturation with CaCO
3
is proposed. For reducing soil organic matter and DOM mobility and loss from soil, as well as for Pb passivation, intra-soil mechanical processing, intra-soil waste management, and intra-soil watering are proposed.
The first Keggin-type Be-containing heteropolyanion BeW12O40(6-) (1(6-)) has been obtained by hydrothermal synthesis from sodium tungstate and Be(NO3)2. It was crystallized as (Bu4N)4.8Na1.2BeW12O40 ...(1a) and (Me2NH2)6BeW12O40·4H2O (1b) salts, which were characterized by (9)Be and (183)W NMR, ESI-MS, CV, and single crystal X-ray diffraction analysis.
•Immobilization of Ni2+ ions at the inner surface of monodisperse spherical mesoporous SiO2 particles.•Monodisperse spherical mesoporous SiO2/Ni particles of 500±25nm diameter as metal affinity ...sorbents.•Diclofenac extraction by IMAC technique.•Addition of PFOS to IMAC eluents improves the recovery degree of diclofenac (up to 98%).•The obtained thermodynamics analysis data indicate the chemical nature of the DCF interaction with the surface of the sorbent.
In this research, a novel IMAC sorbent with high specificity for chlorine-containing compounds was developed. Ni-functionalized monodisperse spherical mesoporous silica particles of 500±25nm diameter were synthesized and their metal affinity properties were studied with the use of diclofenac as the model substance. The particles were aggregatively stable in the pH range of 3–12. The sorbent demonstrated a high adsorption capacity (0.60±0.06μg of DCF per 1mg of the sorbent) and high adsorption/desorption rate (20 and 5min was enough for the sorbent saturation and desorption of DCF, correspondingly). A mixture of eluents with addition of PFOS providing the almost complete recovery (98%) of diclofenac was first proposed. The monodispersity and the high sedimentation and aggregative stability of the particles provide the formation of a stable hydrosol even under ultrasound treatment which makes the mSiO2/Ni particles suitable for batch chromatography.
ESI-MS based methodology for the rapid reactivity screening of PW(11)O(39)RhCl(5-) and PW(11)O(39)Ir(H(2)O)(4-) toward various metalation-intended substrates (reagents with an activated C-H bond, ...boronic acids and organotin compounds) is presented. Formation of a series of new organometallic POM derivatives with Rh-R (R = malonate, phenylacetate, CH(3), Ph, ferrocenyl) and Ir-R (R = CH(3)) bonds is reported.
PDF
