Hasil untuk "Organic chemistry"

Qilin Han, Ying Zhou, Zixian Dong et al.

Abstract Chemotherapy sensitivity is an important factor that restricts the prognosis of breast cancer, and breast cancer stem cells (BCSCs) are the root cause of chemotherapy sensitivity. SNORA47, a member of the small nucleolar RNAs, has not been documented in the context of breast cancer, although it has been reported in lung cancer. In this study, high SNORA47 expression was linked to unfavorable survival outcomes among patients with Luminal A breast cancer in The Cancer Genome Atlas (TCGA). Among Luminal A patients, an elevated expression of SNORA47 correlated with high TNM stage (P = 0.049). SNORA47 was strongly associated with breast cancer stemness phenotype and tumor sensitivity in vivo and in vitro. Our findings demonstrated that SNORA47, through its interaction with early B-cell factor 3(EBF3), facilitated the translocation of ribosomal protein L11(RPL11), which as a modulator that subsequently regulates the expression levels of the oncogene c-Myc. These discoveries provided novel insights into the molecular mechanisms of breast cancer progression and suggested potential therapeutic targets for overcoming drug sensitivity by disrupting the SNORA47-EBF3-RPL11 axis.

Shuwen Liu, Tirusew Tegafaw, Son Long Ho et al.

Owing to their 4f electrons and high atomic numbers, lanthanide (Ln) elements impart lanthanide oxide (Ln₂O₃) nanoparticles with excellent biomedical imaging properties. This study reports synthesis for three types of ultrasmall and monodisperse Ln₂O₃ nanoparticles (Ln = Eu, Gd, and Tb) via thermal decomposition in oleylamine at 280 °C, followed by ligand exchange with citric acid (CA) to produce water-dispersible, CA-grafted Ln₂O₃ nanoparticles with high colloidal stability. The resulting CA-grafted Ln₂O₃ nanoparticles had average diameters of approximately 2 nm. We characterized their physicochemical properties, including in vitro cytotoxicity, magnetic resonance imaging properties (i.e., water proton spin relaxivities), and X-ray imaging properties (i.e., X-ray attenuation).

Mohammad Navvabpour, Safi Jradi, Pierre-Michel Adam et al.

This study presents a simple, high-throughput synthesis approach for fabricating palladium (Pd) nanomaterials with anisotropic shapes, specifically Pd nanorods, via a self-assembly process. This method avoids the use of reducing agents, surface functionalization, and stabilizing agents. Palladium–poly(methyl methacrylate) (Pd-PMMA) nanocomposites were successfully synthesized using a vapor-induced phase separation (VIPS) method. The formation of Pd nanorods was controlled by tuning key parameters, such as the Pd precursor concentration, choice of solvents, and spin coating speed. Notably, the resulting nanorods exhibited high reproducibility and ultrasensitivity as a surface-enhanced Raman scattering (SERS) platform, achieving an enhancement factor of approximately 1.8 × 10⁵, despite the relatively weak plasmonic properties of Pd. This work represents a novel, facile strategy for Pd nanorod synthesis, offering new potential for the design of Pd-based nanosensors for chemical sensing applications.

Elvira Ferrara, Danilo Cice, Simona Piccolella et al.

Walnut processing generates considerable quantities of by-products that could be reprocessed into value-added products that have food and non-food applications. In this context, the aim of this study is to characterize the ‘Sorrento’ and ‘Tulare’ walnut cultivars using the UPOV guidelines and analyze the chemical composition and antioxidant activity of their shells. Insight into the chemical composition of the different granulometric fractions of walnut shell, obtained by sieving, was obtained following ultrasound-assisted extraction by Ultra-High-Performance Liquid Chromatography–High-Resolution Mass Spectrometry (UHPLC-HRMS). The total phenolic, flavonoid, and tannin content and antiradical capacity, obtained by DPPH and ABTS assays, and the Fe(III) reducing power of the extracts were also evaluated. The UHPLC-HRMS analysis indicated the presence of thirty-two compounds ascribable to four major classes of specialized metabolites. Furthermore, the extraction efficiency of gallic acid, ellagic acid derivatives, as well as glansreginin A, increased with the decrease in shell matrix particle size in contrast to chlorogenic acids and flavonoid glycosides. This is the first study to highlight new knowledge on the chemical composition of walnut shells. The results obtained demonstrate the feasibility of recovering valuable bioactive components from agro-waste that may be further valorized.

Hongxing Zheng, Wenrui Yan, Mengli Shao et al.

Diabetic osteoporosis (DOP) is an abnormal metabolic disease caused by long-term hyperglycemia. In this study, a model rat of streptozotocin (STZ)-induced diabetes was established, and chromium picolinate (5 mg·kg⁻¹) was given; the changes in blood glucose and body weight were detected before and after administration; and bone mineral density (BMD), bone morphology, bone turnover markers, inflammatory cytokines, and oxidative stress indicators were observed in each group. We found that after chromium picolinate (CP) intervention for 8 weeks, the blood glucose level was decreased; the BMD, the bone histomorphology parameters, and the pathological structure were improved; the expression of bone resorption-related proteins was downregulated; and the expression of bone formation-related proteins was upregulated. Meanwhile, serum antioxidant activity was increased, and inflammatory cytokine levels were decreased. In conclusion, CP could alleviate DOP by anti-oxidation, inhibition of bone turnover, anti-inflammation, and regulation of the OPG/RANKL/RANK signaling pathway. Therefore, CP has important application values for further development as a functional food or active medicine in DOP treatment.

Manuela B. Nascimento, Lívia R. Amorim, Marcos A. S. Nonato et al.

This study aimed to develop an analytical method using HS-SPME/GC-MS to determine the volatile organic compound (VOC) profiles and evaluate the sensory attributes of cocoa honey from four cocoa varieties (CCN51, PS1319, SJ02, and Parazinho). Using a multivariate factorial experimental design, the HS-SPME/GC-MS method was optimized to determine the VOC profiles. Twenty previously trained tasters participated in the ranking descriptive analysis, while 108 consumers participated in the acceptance and purchase intention tests. A total of 84 volatile organic compounds were identified from various chemical classes, including acids, alcohols, aldehydes, esters, ketones, monoterpenes, oxygenated monoterpenoids, sesquiterpenes, and oxygenated sesquiterpenoids. Palmitic acid was the compound found in the highest concentration in all varieties (5.13–13.10%). Multivariate analysis tools identified key compounds for differentiation and grouping of the samples. The results revealed that the variety significantly influenced both the VOCs’ concentrations and sensory profiles. The CCN51, PS1319, and SJ02 varieties exhibited the highest diversity of VOCs and sensory attributes. Notably, the SJ02 and CCN51 varieties demonstrated superior acceptability and purchase intention, with means ranging from 7.21 and 7.08 to 3.71 and 3.56, respectively. These results indicate their potential as promising sources of cocoa honey for the food industry.

Alexander G. Dimitrov

Mitochondrial permeability transition pore (mPTP) channel plays a central role in cell death because it mediates the effect of a sudden large opening of the inner mitochondrial membrane. Its associations with adenine nucleotide translocase and with ATP synthase within the general framework of mPTP research were challenged by genetic knock out experiments. This paper proposes the hypothesis that the matrix ATP regulates the mPTP. That hypothesis not only succeeds in classifying and explaining the existing experimental data but it also fits quite well to a peripheral branch of mPTP research proposing that the channel is composed of a combination of polyphosphates and poly-(R)-3-hydroxybutyrates glued by Ca ions. ATP also has a polyphosphate part and thus could be potentially incorporated into such kind of a channel. ATP not only has the potential to decrease the effective channel cross-section when the matrix ATP pool is full, but also, having four negative charges, ATP could be driven across the membrane, together with some accompanying metal ions. Thus, an effective potassium hydrogen exchanger is constructed. Cell death and “permeability transition” happen when the matrix ATP pool is emptied and so the mPTP channel is emptied from the ATP. As a result, the effective channel cross-section would greatly increase; instead of effectively going out, potassium would go in, and the matrix would burst. Hence, the regulation of the matrix ATP level could explain the effect of cyclosporin A – the main experimental modulator of mPTP channel activity, the mechanism of hypoxic/reperfusion injury, and many other.

Mohammad S. Rahman, Vinay Bharadwaj, Anau K. H. S. Lautaha et al.

Photoactive <i>N</i>-hydroxysulfonamides photocaged with the (6-bromo-7-hydroxycoumarin-4-yl)methyl chromophore have been successfully synthesized, and the mechanisms of photodecomposition investigated for two of the compounds. Upon irradiation up to 97% of a diagnostic marker for (H)NO release, sulfinate was observed for the trifluoromethanesulfonamide system. In the absence of a species that reacts rapidly with (H)NO, (H)NO instead reacts with the carbocation intermediate to ultimately generate (<i>E</i>)-BHC-oxime and (<i>Z</i>)-BHC-oxime. Alternatively, the carbocation intermediate reacts with solvent water to give a diol. Deprotonation of the N(H) proton is required for HNO generation via concerted C-O/N-S bond cleavage, whereas the protonation state of the O(H) does not affect the observed photoproducts. If the N(H) is protonated, C-O bond cleavage to generate the parent <i>N</i>-hydroxysulfonamide will occur, and/or O-N bond cleavage to generate a sulfonamide. The undesired competing O-N bond cleavage pathway increases when the volume percentage of water in acetonitrile/water solvent mixtures is increased.

Wen Li, Zichao Xiang, Wenjing Yu et al.

Abstract Inflammation is a common and important pathological process occurring in any part of the body and relating to a variety of diseases. Effective tissue repair is critical for the survival of impaired organisms. Considering the side effects of the currently used anti-inflammatory medications, new therapeutic agents are urgently needed for the improvement of regenerative capacities of inflammatory-impaired tissues. Mesenchymal stromal stem/progenitor cells (MSCs) are characterized by the capabilities of self-renewal and multipotent differentiation and exhibit immunomodulatory capacity. Due to the ability to modulate inflammatory phenotypes and immune responses, MSCs have been considered as a potential alternative therapy for autoimmune and inflammatory diseases. Natural compounds (NCs) are complex small multiple-target molecules mostly derived from plants and microorganisms, exhibiting therapeutic effects in many disorders, such as osteoporosis, diabetes, cancer, and inflammatory/autoimmune diseases. Recently, increasing studies focused on the prominent effects of NCs on MSCs, including the regulation of cell survival and inflammatory response, as well as osteogenic/adipogenic differentiation capacities, which indicate the roles of NCs on MSC-based cytotherapy in several inflammatory diseases. Their therapeutic effects and fewer side effects in numerous physiological processes, compared to chemosynthetic drugs, made them to be a new therapeutic avenue combined with MSCs for impaired tissue regeneration. Here we summarize the current understanding of the influence of NCs on MSCs and related downstream signaling pathways, specifically in pathological inflammatory conditions. In addition, the emerging concepts through the combination of NCs and MSCs to expand the therapeutic perspectives are highlighted. A promising MSC source from oral/dental tissues is also discussed, with a remarkable potential for MSC-based therapy in future clinical applications.

Abdelrahim Alqudah, Esam Y. Qnais, Mohammed A. Wedyan et al.

Background: Isorhamnetin is a flavonoid that is found in medical plants. Several studies showed that isorhamnetin has anti-inflammatory and anti-obesity effects. This study aims to investigate the anti-diabetic effects of isorhamnetin in a high-fat diet and Streptozotocin-(HFD/STZ)-induced mice model of type 2 diabetes. Materials and Methods: Mice were fed with HFD followed by two consecutive low doses of STZ (40 mg/kg). HFD/STZ diabetic mice were treated orally with isorhamnetin (10 mg/kg) or (200 mg/kg) metformin for 10 days before sacrificing the mice and collecting plasma and soleus muscle for further analysis. Results: Isorhamnetin reduced the elevated levels of serum glucose compared to the vehicle control group (<i>p</i> < 0.001). Isorhamnetin abrogated the increase in serum insulin in the treated diabetic group compared to the vehicle control mice (<i>p</i> < 0.001). The homeostasis model assessment of insulin resistance (HOMA-IR) was decreased in diabetic mice treated with isorhamnetin compared to the vehicle controls. Fasting glucose level was significantly lower in diabetic mice treated with isorhamnetin during the intraperitoneal glucose tolerance test (IPGTT) (<i>p</i> < 0.001). The skeletal muscle protein contents of GLUT4 and p-AMPK-α were upregulated following treatment with isorhamnetin (<i>p</i> > 0.01). LDL, triglyceride, and cholesterol were reduced in diabetic mice treated with isorhamnetin compared to vehicle control (<i>p</i> < 0.001). Isorhamnetin reduced MDA, and IL-6 levels (<i>p</i> < 0.001), increased GSH levels (<i>p</i> < 0.001), and reduced GSSG levels (<i>p</i> < 0.05) in diabetic mice compared to vehicle control. Conclusions: Isorhamnetin ameliorates insulin resistance, oxidative stress, and inflammation. Isorhamnetin could represent a promising therapeutic agent to treat T2D.

Altaf Al-Romaiyan, Shanta J. Persaud, Peter M. Jones

Background: Folk medicines are attractive therapeutic agents for treating type 2 diabetes mellitus (T2DM). Most plant extracts that have been suggested to restore β-cells function were tested in vivo. Some only have been tested in vitro to determine whether they have a direct effect on β-cells islets of Langerhans. Currently, there are no defined criteria for screening of β-cell-directed plant-based remedies as potential antidiabetic agents. Summary: In this review, we have identified certain criteria/characteristics that can be used to generate a “screening portfolio” to identify plant extracts as potential β-cell-directed agents for the treatment of T2DM. To validate our screening method, we studied the potential therapeutic efficacy of a <i>Gymnema sylvestre</i> (GS) extract using the screening criteria detailed in the review. Six criteria have been identified and validated using OSA^®, a GS extract. By using this screening method, we show that OSA^® fulfilled most of the criteria identified for an effective β-cell-directed antidiabetic therapy, being an effective insulin-releasing agent at nontoxic concentrations; maintaining β-cell insulin content by stimulating a concomitant increase in insulin gene transcription; maintaining β-cell mass by protecting against apoptosis; and being effective at maintaining normoglycemia in vivo in a mouse model and a human cohort with T2DM. Key messages: The present review has highlighted the importance of having a screening portfolio for plant extracts that have potential antidiabetic effects in the treatment of T2DM. We propose that this screening method should be adopted for future studies to identify new β-cell-directed antidiabetic plant derived agents.

Gbadebo İsmaila Olatona, Oluwapelumi Ajilore, Fakunle Mutiu Alani et al.

The estimation of solar radiation intensity has been a focus of many researchers due to the cost of setting up its actual measurements. While many of them employed empirical models, this study utilizes the artificial neural network for the analysis and estimation of global solar radiation over two Nigerian cities. The model developed using sunshine hours, temperatures and relative humidity were compared with the existing empirical models. Model performance indicators comparing the measured data and the computed data for the derived and selected models, using the same number of input meteorological parameters showed that ANN having average values of RMSE, MBE, and MPE of 0.0744 MJm-2day-1, -0.0020 MJm-2day-1, and -0.0043%, respectively, performed slightly better. When different number of input meteorological parameters were used, the ANN gave the following error indicators for RMSE, MBE, MPE of 0.0394MJm-2day-1, -0.0023MJm-2day-1 and -0.0144% respectively. Also, in the result of solar radiation in Abuja, using the same number of meteorological parameters, the model with the best performance in the estimation of solar radiation is the ANN model with average values of RMSE, MBE, MPE of 0.1301MJm-2day-1, 0.0053MJm-2day-1 and 0.0441% respectively. Hence, the models are versatile for predicting global solar radiation in locations in the same climatic zones as locations studied in this study, where direct measurements of solar radiation is scarce and widely separated but there is availability of commonly measured meteorological parameters such as sunshine duration, minimum temperature, maximum temperature and relative humidity.

Adebanke Ogundipe, Babatunde Adetuyi, Franklyn Iheagwam et al.

Background and Objectives. Moringa oleifera has been scientifically reported to have effects on diabetes and obesity. An explanatory mechanism on how the plant exerts its enzyme inhibitory activities are yet to be detailed. This study was aimed at carrying out an in vitro assessment of ethanolic extracts (AEEs) of M. oleifera leaves for their antioxidant, antidiabetic, and antiobesity activities. Methods. Phytochemical screening, antioxidant activity, α-amylase, and α-lipase inhibitory assessment were carried out on Moringa oleifera extract. Results. The result of the phytochemical screening revealed the presence of total phenolic, flavonoid, tannin, and alkaloid contents of values 0.070 ± 0.005 mg gallic acid equivalent/g, 0.180 ± 0.020 mg rutin equivalent/g, 0.042 ± 0.001 mg tannic equivalent/g, and 12.17 ± 0.001%, respectively, while the total protein analysis was 0.475 ± 0.001 mg bovine serum albumin equivalent/g. Ferric reducing antioxidant power (FRAP) and total antioxidant capacity (TAC) values were 0.534 ± 0.001 mg gallic acid equivalent/g and 0.022 ± 0.00008 mg rutin equivalent/g, respectively. Diphenyl-2-picrylhydrazyl (DPPH), ABTS (2,2′-azino-bis (ethylbenzothiazoline-6-sulfonic acid)), and nitric oxide (NO) assays showed the extract to have a strong free radical scavenging activity. The 50% inhibitory concentration (IC50) values of the lipase and amylase activities of the extract are 1.0877 mg/mL and 0.1802 mg/mL, respectively. Conclusion. However, α-lipase and α-amylase inhibiting activity of M. oleifera could be related to the phytochemicals in the extract. This research validates the ethnobotanical use of M. oleifera leaves as an effective plant-based therapeutic agent for diabetes and obesity.

Chanyanut Wongsa, Suruk Udomsom, Apiwat Budwong et al.

We proposed a specially designed sequential injection (SI) amperometric system coupling with a bioreactor for in-line glucose monitoring in cell culture. The system is composed of three main parts which are the bioreactor, SI system, and electrochemical detection unit. The bioreactor accommodates six individual cell culture units which can be operated separately under different conditions. The SI system enables automatic in-line sampling and in-line sample dilution, with a specially designed mixing unit; therefore, it has the benefits of fast analysis time and less contamination risk. The use of 3D-printed microfluidic components, a mixing channel, and a flow cell helped to reduce operational time and sample volume. A disposable screen-printed electrode (SPE), modified with glucose oxidase (GOD), carbon nanotube, and gold nanoparticle, was used for detection. The developed system provided a linear range up to 3.8 mM glucose in cell culture media. In order to work with cell culture in higher glucose media, the in-line sample dilution can be applied. The developed SI system was demonstrated with mouse fibroblast (L929) cell culture. The results show that glucose concentration obtained from the SI system is comparable with that obtained from the conventional colorimetric method. This work can be further developed and applied for in vitro cell-based experiments in biomedical research.

Diego Peña Lara, Hernando Correa, Jesús Evelio Diosa

The superionic conductor, solid state, and body-centered cubic structure, silver iodide at room temperature, has been studied via molecular dynamics simulations. The calculated results using pairwise Coulomb-Buckingham potential, zero pressure on the sample, a semi-rigid model system of 1000 Ag and 1000 I ions, (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>N</mi><mi>V</mi><mi>E</mi></mrow></semantics></math></inline-formula>) as a statistical ensemble, and an effective charge of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>Z</mi><mo>=</mo><mn>0.63</mn></mrow></semantics></math></inline-formula> for the pairs Ag-Ag and I-I, were found to be consistent with experimental data and one study using <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>Z</mi><mo>=</mo><mn>0.60</mn></mrow></semantics></math></inline-formula>, different potential, and simulation software. For the pair Ag-I, there is a discrepancy due to the high silver ion diffusion. The calculated value of the diffusion constant of the silver ion is greater than iodide ion. The dynamic transport properties (mean square displacement, velocity autocorrelation function) results indicated typical behavior reported by other authors, using different potentials in their DM simulations for iodine and silver ions.

V. О. Stetska, T. V. Dovbynchuk, N. V. Dziubenko et al.

Parkinson’s disease (PD) is neurodegenerative disease, which is accompanied by degeneration of dopaminergic neurons in subtantia nigra. Non-motor symptoms, in particular, disorders of the gastrointestinal (GI) tract are observed in 20-80% of patients some 15-20 years before clinically diagnosed PD and are not a least important feature of PD pathogenesis. The transient receptor potential (TRP) channels are expressed throughout the GI tract, where they play an important role in taste, thermoregulation, pain, mucosal function and homeostasis, control of interstitial motility etc. The aim of this study was to investigate the contribution of TRPV4 and TRPM8 channels in the GI motor function in the colon of rats with PD, incduced by injection of the 12 μg 6-hydroxydopamine (6-OHDA). The studies were performed on the 4th week and the 7th month after PD induction The rats were randomly divided into: I group – the sham-lesioned rats, 4 μl 0.9% NaCl, autopsy 4 weeks after injection (n = 5); II group – the 6-OHDA-PD rats, 4 μl 12 μg of 6-OHDA, autopsy 4 weeks after injection (n = 5); III group – the sham-lesioned rats, 4 μl 0.9% NaCl, autopsy 7 months after injection (n = 4); IV group – the 6-OHDA-PD rats, 4 μl 12 μg of 6-OHDA, autopsy 7 months after injection (n = 5). We evaluated the body weight of rats, GI transit time, the cecum weight index and immunohistochemical identification of tyrosine hydroxylase (TH) -positive cells, and TRPV4, TRPM8 expression in rat’s colon. We showed that on the 7th month of the experiment, the GI transit time doubles over time; the cecum weight index of 6-OHDA rats increased by 57%; the number of TH-positive cells in colon rats decreased 2-fold, while TRPM8 ion channels were downregulated in PD rats and TRPV4 ion channels were upregulated in the colon of rats with 6-OHDA-PD. It was concluded that TRPV4 and TRPM8 ion channels may be considered pharmacological targets in the progression of PD pathology.

Dóra Lakk-Bogáth, Patrik Török, Flóra Viktória Csendes et al.

Heme iron and nonheme dimanganese catalases protect biological systems against oxidative damage caused by hydrogen peroxide. Rubrerythrins are ferritine-like nonheme diiron proteins, which are structurally and mechanistically distinct from the heme-type catalase but similar to a dimanganese KatB enzyme. In order to gain more insight into the mechanism of this curious enzyme reaction, non-heme structural and functional models were carried out by the use of mononuclear [Fe^II(L_1–4)(solvent)₃](ClO₄)₂ (<b>1</b>–<b>4</b>) (L₁ = 1,3-bis(2-pyridyl-imino)isoindoline, L₂ = 1,3-bis(4′-methyl-2-pyridyl-imino)isoindoline, L₃ = 1,3-bis(4′-Chloro-2-pyridyl-imino)isoindoline, L₄ = 1,3-bis(5′-chloro-2-pyridyl-imino)isoindoline) complexes as catalysts, where the possible reactive intermediates, diiron-perroxo [Fe^III₂(μ-O)(μ-1,2-O₂)(L₁-L₄)₂(Solv)₂]²⁺ (<b>5</b>–<b>8</b>) complexes are known and well-characterized. All the complexes displayed catalase-like activity, which provided clear evidence for the formation of diiron-peroxo species during the catalytic cycle. We also found that the fine-tuning of iron redox states is a critical issue, both the formation rate and the reactivity of the diiron-peroxo species showed linear correlation with the Fe^III/Fe^II redox potentials. Their stability and reactivity towards H₂O₂ was also investigated and based on kinetic and mechanistic studies a plausible mechanism, including a rate-determining hydrogen atom transfer between the H₂O₂ and diiron-peroxo species, was proposed. The present results provide one of the first examples of a nonheme diiron-peroxo complex, which shows a catalase-like reaction.

Ole Johan Juvik, Bjarte Holmelid, George W. Francis et al.

Extensive regional droughts are already a major problem on all inhabited continents and severe regional droughts are expected to become an increasing and extended problem in the future. Consequently, extended use of available drought resistant food plants should be encouraged. Bromelia laciniosa, Neoglaziovia variegata and Encholirium spectabile are excellent candidates in that respect because they are established drought resistant edible plants from the semi-arid Caatinga region. From a food safety perspective, increased utilization of these plants would necessitate detailed knowledge about their chemical constituents. However, their chemical compositions have previously not been determined. For the first time, the non-polar constituents of B. laciniosa, N. variegata and E. spectabile have been identified. This is the first thorough report on natural products from N. variegata, E. spectabile, and B. laciniosa. Altogether, 20 non-polar natural products were characterized. The identifications were based on hyphenated gas chromatography-high resolution mass spectrometry (GC-HRMS) and supported by 1D and 2D Nuclear Magnetic Resonance (NMR) plant metabolomics.

Arthur A. Spector, Hee-Yong Kim

Dietary fat was recognized as a good source of energy and fat-soluble vitamins by the first part of the 20th century, but fatty acids were not considered to be essential nutrients because they could be synthesized from dietary carbohydrate. This well-established view was challenged in 1929 by George and Mildred Burr who reported that dietary fatty acid was required to prevent a deficiency disease that occurred in rats fed a fat-free diet. They concluded that fatty acids were essential nutrients and showed that linoleic acid prevented the disease and is an essential fatty acid. The Burrs surmised that other unsaturated fatty acids were essential and subsequently demonstrated that linolenic acid, the omega-3 fatty acid analog of linoleic acid, is also an essential fatty acid. The discovery of essential fatty acids was a paradigm-changing finding, and it is now considered to be one of the landmark discoveries in lipid research.

I.M. Romanova, М.А. Zhivet’yev, Т.А. Penzina et al.

The study was aimed to analyse changes in peroxidase activity of common pine needles throughout the year. The needles of the 1-st, 2-nd and 3-d years were collected. Total activity of guaiacol-dependent peroxidase was determined. Minimum peroxidase activity is observed in January and February. In March intense overall activation of peroxidase is observed in the needles of all ages, which might be related to spring enhancement of physiological processes and activation of metabolism. Autumn period is characterized by more or less high activities of guaiacol peroxidase from September till November, which is related to its participation in stress-adaptation to low temperatures in winter. Peroxidase activity changes depending on the season of the year. Needles of different age are characterized by their own peroxidase activity level in various time periods.