Aliphatic Polyamines Research Articles

Azoximer bromide and hydroxyapatite: promising immune adjuvants in cancer.

Immune adjuvants are immune modulators that have been developed in the context of infectious vaccinations. There is currently a growing interest in immune adjuvants due to the development of immunotherapy against cancers. Immune adjuvant mechanisms of action are focused on the initiation and amplification of the inflammatory response leading to the innate immune response, followed by the adaptive immune response. The main activity lies in the support of antigen presentation and the maturation and functions of dendritic cells. Most immune adjuvants are associated with a vaccine or incorporated into the new generation of mRNA vaccines. Few immune adjuvants are used as drugs. Hydroxyapatite (HA) ceramics and azoximer bromide (AZB) are overlooked molecules that were used in early clinical trials, which demonstrated clinical efficacy and excellent tolerance profiles. HA combined in an autologous vaccine was previously developed in the veterinary field for use in canine spontaneous lymphomas. AZB, an original immune modulator derived from a class of heterochain aliphatic polyamines that is licensed in Russia, the Commonwealth of Independent States, and Slovakia for infectious and inflammatory diseases, is and now being developed for use in cancer with promising results. These two immune adjuvants can be combined in various immunotherapy strategies.

Spermidine suppresses oxidative stress and ferroptosis by Nrf2/HO-1/GPX4 and Akt/FHC/ACSL4 pathway to alleviate ovarian damage

AimsOxidative stress is considered to be one of the culprits of ovarian dysfunction. Spermidine (SPD) is a natural aliphatic polyamine that is widely present in living organisms and has been shown to exert preventive effects on various ageing-related diseases. This study seeks to investigate the potential preventive and protective effects of SPD on ovarian oxidative damage. Main methodsOvarian oxidative stress model in C57BL/6 mice was established by 3-nitropropionic acid. Female mice were administrated 10 mg/kg or 15 mg/kg SPD. The estrous cycle, serum hormone levels and mating test were measured to evaluate ovarian function. Follicle counts and AMH levels to assess ovarian reserve. Masson's trichrome to assess ovarian fibrosis. TUNEL analysis to evaluate follicular granulosa cells (GCs) apoptosis. Oxidative stress and autophagy indicators (Nrf2, HO-1, GPX4, LC3B, P62) were measured in vivo and in vitro. RNA-sequencing was performed on SPD-treated GC to study the effects of SPD on Akt and FHC/ACSL4 signaling. Key findingsSPD supplementation improved ovarian endocrine function and reproductive capacity in oxidative stress mice. SPD regularized the estrous cycle and alleviated oxidative stress. Furthermore, SPD increased the ovarian reserve, reducing GC apoptosis by activating the Nrf2/HO-1/GPX4 pathway. RNA-sequencing showed that SPD induced 230 genes changes in porcine GC, which were mainly involved in oocyte meiosis, arginine biosynthesis and glutathione metabolism pathways. SPD attenuated H2O2-induced ferroptosis by regulating Akt/FHC/ACSL4 signaling. SignificanceSPD alleviates oxidative stress and ferroptosis by regulating the Nrf2/HO-1/GPX4 and Akt/FHC/ACSL4 pathway, which may be a novel potential strategy to protect ovarian oxidative damage.

SELECTIVE ADMINISTRATION OF POLYAMINE-DEFICIENT AND POLYAMINE-FREE DIETS TO CANCER PATIENTS

Abstract Aliphatic polyamines (putrescin, spermidine, spermine and cadaverine) play an important role in the induction of neoplastic processes leading to cell malignancy. In malignantly transformed cells, a high level of aliphatic polyamines has been observed, which ensures their steady anaplastic growth. This is precisely why elevated levels of the aforementioned polyamines are considered as diagnostic and prognostic criteria for a wide range of oncological diseases. In several developed countries, cancer patients are advised to follow a low-polyamine diet, including specifically those food products that are identified in the general nutrient registry as having low levels of aliphatic polyamines. However, when recommending such a diet, many researchers did not pay attention to the fact that in different food products, the ratio of polyamine levels often varies within very wide limits. Therefore, as some researchers report a polyamine-deficient diet prescribed to cancer patients is not always effective. We analyzed various literary sources and identified products that do not contain polyamines or contain them in very low quantities. Based on the analysis of available literary data, when patients are admitted to oncology clinics, along with generally accepted laboratory diagnostic criteria, it is necessary to include diagnostic indicators for determining the levels of aliphatic polyamines in erythrocytes and blood plasma, including putrescine, spermidine, spermine, and cadaverine. Due to this approach, oncologists and nutritionists may have a real opportunity to prescribe a selective polyamine-deficient diet. For patients with advanced cancer, we recommend the use of a polyamine-free diet instead of a polyamine-deficient one.

Cellulose derivatives functionalized with multidentate N‑donor atoms: comparative adsorption of cadmium (II) and lead (II) ions from water

Cellulose derivatives functionalized with multidentate N‑donor atoms containing two, three and four amino functional groups (as marked N2–CL, N3–CL and N4–CL) have been prepared by grafting of linear aliphatic polyamines into the cellulose backbone through the Schiff base reaction. An increase in the adsorptive amounts of Cd2+ and Pb2+ with increasing N‑donor atoms of the grafted polyamines onto the cellulose backbone and the maximum capacity of N4–CL > N3–CL > N2–CL are found. The N4–CL with the highest N content (up to 5.2 mmol N g−1) exhibits the largest adsorptive capacities of 249.7 mg g−1 for Cd2+ and 401.2 mg g−1 for Pb2+. The adsorption of both the ions by the three cellulose derivatives is achieved within 30 min, is independent of pH in the range of 4.5–6 for Cd2+ and 4–6 for Pb2+, and can be satisfactorily fitted by Langmuir and pseudo-second-order equations. Thermodynamic parameters suggest an endothermic and endothermic nature.

Exploring polyamine interactions and binding pockets in SARS-CoV-2 ORF3a

Ongoing global pandemic caused by coronavirus (COVID-19) requires urgent development of vaccines, treatments, and diagnostic tools. Open reading frame 3a (ORF3a) from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is considered to be a potential drug target for COVID-19 treatment. ORF3a is an accessory protein that plays a significant role in virus-host interactions and in facilitating host immune responses. Using putrescine, spermidine and spermine, an aliphatic polyamine for the activity suppression of ORF3a appears to be a promising approach in finding new targets for drug design. In this study, we explored the possible binding poses of polyamines to the ORF3a protein using a combination of various computational approaches i.e. pocket prediction, blind and site-specific molecular docking, molecular dynamics and ligand flooding simulations. The results showed that the tip of cytoplasmic domain and the upper tunnel of transmembrane domain of ORF3a provide a suitable binding site specific for the polyamines. MD simulations revealed the stability of spermidine binding in the upper tunnel pocket of ORF3a through salt bridge and hydrogen bond interactions between the amine groups of the ligand and negatively charged residues of ORF3a. These findings can be helpful in designing new therapeutic drugs.

Concentration-Guided Visual Detection of Multiphase Aliphatic Biogenic Amines through Amine-Phenol Recognition Using a Dual-State Emitter.

Intermolecular amine-phenol interactions are largely recognized as unique models with diverse supramolecular interactions. However, fluorescence (FL) variations originating from such interactions are rare. Herein, FL changes are well realized from amine-phenol interactions to identify an important biomarker, biogenic amines (BAs). A simple, inexpensive, and thermally stable anthracenylphosphonate is linked with 2,2'-biphenol to design a functional dual-state emitter. Among the various amines tested, this emitter displays superior sensitivity with the lowest possible limit of detection as 5.8-9.7 ppb with aliphatic polyamines such as 1,3-, 1,4-, 1,5-, and 1,6- diamines and spermidine in the solution phase. Fast, on-spot detection of the BA vapors was visually conducted through a notable high-contrast change from blue to yellow emission in the solid state. FT-IR, 1H/31P NMR, and mass spectroscopic studies identify the ground-state amine-phenol interactions. The failure in BA detection with the 2,2'-dimethoxy-biphenyl-linked analog verifies the role of amine-phenol interactions. Mechanistic studies determine amine-phenol interactions in the ground and excited states. The molecular structure and packing of the doubly twisted probe are documented with a substantial void space facilitating close contact of the BAs with the strong amine-phenol interactions desired for efficient detection. Finally, this probe governs the freshness of a piece of Catla catla fish and prawn. Further, a remarkable concentration-controlled diverse emission with a red shift difference of 141 nm is detected with 1,3-diaminopropane (1,3-DAP) vapor (from 29 to 319 mg/L) for the first time. Thus, a cost-effective device is developed to detect 1,3-DAP at a precise concentration, visible through the naked eye.

Biochemical and structural basis of polyamine, lysine and ornithine acetylation catalyzed by spermine/spermidine N-acetyl transferase in moss and maize.

Polyamines such as spermidine and spermine are essential regulators of cell growth, differentiation, maintenance of ion balance and abiotic stress tolerance. Their levels are controlled by the spermidine/spermine N1 -acetyltransferase (SSAT) via acetylation to promote either their degradation or export outside the cell as shown in mammals. Plant genomes contain at least one gene coding for SSAT (also named NATA for N-AcetylTransferase Activity). Combining kinetics, HPLC-MS and crystallography, we show that three plant SSATs, one from the lower plant moss Physcomitrium patens and two from the higher plant Zea mays, acetylate various aliphatic polyamines and two amino acids lysine (Lys) and ornithine (Orn). Thus, plant SSATs exhibit a broad substrate specificity, unlike more specific human SSATs (hSSATs) as hSSAT1 targets polyamines, whereas hSSAT2 acetylates Lys and thiaLys. The crystal structures of two PpSSAT ternary complexes, one with Lys and CoA, the other with acetyl-CoA and polyethylene glycol (mimicking spermine), reveal a different binding mode for polyamine versus amino acid substrates accompanied by structural rearrangements of both the coenzyme and the enzyme. Two arginine residues, unique among plant SSATs, hold the carboxyl group of amino acid substrates. The most abundant acetylated compound accumulated in moss was N6 -acetyl-Lys, whereas N5 -acetyl-Orn, known to be toxic for aphids, was found in maize. Both plant species contain very low levels of acetylated polyamines. The present study provides a detailed biochemical and structural basis of plant SSAT enzymes that can acetylate a wide range of substrates and likely play various roles in planta.

Structural change study of pepsin in the presence of spermidine trihydrochloride: Insights from spectroscopic to molecular dynamics methods

Spermidine is an aliphatic polyamine that directs a set of biological processes. This work aimed to use UV–Vis spectroscopy, fluorescence spectroscopy, thermal stability, kinetic methods, docking, and molecular dynamic simulations to examine the influence of spermidine trihydrochloride (SP) on the structure and function of pepsin. The results of the fluorescence emission spectra indicated that spermidine could quench pepsin's intrinsic emission in a static quenching process, resulting in the formation of the pepsin-spermidine complex. The results discovered that spermidine had a strong affinity to the pepsin structure because of its high binding constant. The obtained results from spectroscopy and molecular dynamic approaches showed the binding interaction between spermidine and pepsin, induced micro-environmental modifications around tryptophan residues that caused a change in the tertiary and secondary structure of the enzyme. FTIR analysis showed hypochromic effects in the spectra of amide I and II and redistribution of the helical structure. Moreover, the molecular dynamic (MD) and docking studies confirmed the experimental data. Both experimental and molecular dynamics simulation results clarified that electrostatic bond interactions were dominant forces.

Exogenous Spermidine Alleviated Waterlogging Damages in Two Varieties of Camellia oleifera

The potential management of waterlogging-damaged plants can be through the promotion of aliphatic polyamine accumulation, such as spermidine (SPD), in non-accumulator and accumulator species under stress. Camellia oleifera, commonly called tea oil, is an evergreen shrub confronting waterlogged soils in Hainan forest plantations during the pluvial season. As far as we know, few studies focused on the responses of C. oleifera to abiotic stresses, such as waterlogging (WL), and the involvement of SPD in WL tolerance remains unclear. Therefore, two cultivars of C. oleifera (CoH1 and CoH2) were subjected to WL and exogenous SPD to shed light on the role of SPD on WL tolerance via the morphological and physio-biochemical responses of C. oleifera under stress. The results showed that the two varieties of C. oleifera were sensitive to WL stress, and spraying SPD enhanced WL tolerance via root activities, photosynthesis, redox-homeostasis, antioxidant machinery, and compatible solute components. Thus, exogenous SPD significantly reduced the damages caused by WL in C. oleifera seedlings. Moreover, the alternative oxidase (AOX) protein content was down regulated by WL in both varieties of C. oleifera, whereas exogenous SPD enhanced the AOX protein under stress. The two varieties of C. oleifera generally had similar morphological and physiological responses to WL. However, CoH2 demonstrated better photosynthesis compared to CoH1. The results of the present study provide a significant outlook to improve the accumulation of SPD in trees under abiotic stress, particularly via genome editing techniques.

The role of polyamines in the regenerative process of skin aerobic-purulent wounds

Aliphatic polyamines (putrescine, spermidine, spermine) are organic polycations that play an important role in wound healing by stimulating several cellular mechanisms. In a human skin wound sample, the activity of the enzyme ornithine decarboxylase, which regulates the rate of polyamine synthesis, rapidly increases along the wound edges and leads to the activation of the polyamine synthesis cascade. Under the influence of polyamines, some signaling systems are also activated in wounds, which are the main pathways for the release of cellular mechanisms, and thanks to them, the healing process begins in wounds. For example, spermine induces the synthesis of urokinase-type plasminogen activator, the binding of which to the corresponding receptor at the wound margins executes the urokinase-type plasminogen activator and its receptor signaling system, which is the main driver of keratinocyte migration. Eukaryotic cell proliferation depends on precise modification of the eukaryotic initiation factor 5A1, in which spermidine plays an indispensable role. However, in addition to the significant functions performed by polyamines in the human body, polyamines are also necessary for the normal growth and development of fungi and bacteria. Small amounts of some microorganisms have a positive effect on the healing of wounds, but their increase, on the contrary, leads to the impairment of the normal course of wound healing due to their enhanced synthesis of polyamines. On the other hand, many studies show that excess ornithine decarboxylase and polyamines increase the risk of skin cancer. Suppression of polyamine synthesis by pathogenic microflora during wound healing can contribute to both rapid healing and the prevention of skin cancer. In our study, we offer a way of inhibition of polyamine synthesis by wound microflora for rapid wound healing and prevention of subsequent cancer. The medicinal mixture “Armenicum/Eflornithine” is a mixture of the drug “Armenicum” and α-difluoromethylornithine.

Nicotine-Dependent Risk Of Developing Parkinson’s Disease

For the past twenty years, information concerning the relationship between Parkinson’s disease and the use of tobacco products has appeared in highly respected scientific publications. As a whole, these studies were epidemiological. As a rule, these studies showed that individuals who abused tobacco products for many years and quit smoking only in old age had a significantly increased risk of developing Parkinson’s disease. Only a few studies have attempted to identify the structural-functional relationship between the effects of nicotine on the representative brain areas responsible for the onset of Parkinson’s disease. During prolonged tobacco use, nicotine that enters the brain tissue activates the nicotine-dependent acetylcholine receptors localized in dopaminergic neurons, resulting in the release of dopamine. In this study, we attempted to investigate the mechanisms underlying the onset of Parkinson’s disease in individuals who have quit smoking, i.e. under conditions of nicotine withdrawal in the brain.” In our opinion, the “preventive effect” of nicotine on dopaminergic neurons is realized through four interdependent mechanisms: 1. By the receptor mechanism, due to the nicotine-dependent acetylcholine receptors located on dopaminergic neurons, 2. Due to the balanced release and reuptake of dopamine to dopaminergic neurons, 3. Due to prevention of α-synuclein aggregation and fibrillation process, 4. Due to the inhibitory effect of nicotine on the processes of activating the synthesis of aliphatic polyamines in dopaminergic neurons of the corpus striatum and nucleus caudatum. In cases of nicotine “deficiency”, neurodegenerative disorders pathognomonic for Parkinson’s disease can occur in the brain: 1. The exchange of dopamine and aliphatic polyamines in dopaminergic neurons is disturbed, 2. The processes of transforming native α-synuclein into its aggregated and fibrillar forms are intensified, 3. Ultimately, the intraneuronal dopamine-synuclein complex with a pronounced neurotoxic action spectrum may appear. 4. Older adults, in conditions of abrupt smoking cessation, are recommended to use Eflornithine, as well as a polyamine-free and polyamine-deficient diet.

Recent Advances in Fluorescent Methods for Polyamine Detection and the Polyamine Suppressing Strategy in Tumor Treatment.

The biogenic aliphatic polyamines (spermine, spermidine, and putrescine) are responsible for numerous cell functions, including cell proliferation, the stabilization of nucleic acid conformations, cell division, homeostasis, gene expression, and protein synthesis in living organisms. The change of polyamine concentrations in the urine or blood is usually related to the presence of malignant tumors and is regarded as a biomarker for the early diagnosis of cancer. Therefore, the detection of polyamine levels in physiological fluids can provide valuable information in terms of cancer diagnosis and in monitoring therapeutic effects. In this review, we summarize the recent advances in fluorescent methods for polyamine detection (supramolecular fluorescent sensing systems, fluorescent probes based on the chromophore reaction, fluorescent small molecules, and fluorescent nanoparticles). In addition, tumor polyamine-suppressing strategies (such as polyamine conjugate, polyamine analogs, combinations that target multiple components, spermine-responsive supramolecular chemotherapy, a combination of polyamine consumption and photodynamic therapy, etc.) are highlighted. We hope that this review promotes the development of more efficient polyamine detection methods and provides a comprehensive understanding of polyamine-based tumor suppressor strategies.

Preparation and properties of self‐healable solid‐state polymer electrolytes based on covalent adaptive networks enabled by disulfide bond

AbstractCovalent adaptive networks (CANs) have numbers of versatile abilities derived from topological reshuffling with interesting potentials. Here, self‐healable solid‐state polymer electrolytes were developed by integrating epoxy‐resin‐based CANs enabled by disulfide bond with a solid lithium salt (LiTFSI). The disulfide bond was introduced by using a disulfide‐containing aliphatic polyamine as the epoxy‐curing agent. To determine the cure cycle of this epoxy‐resin system, the curing kinetics in the presence of LiTFSI was studied by nonisothermal differential scanning calorimetry. The prepared ion‐conducting (IC) CANs with different LiTFSI content were optically transparent and self‐healable at temperatures above glass transition temperature (Tg). The effect of LiTFSI content on the thermal stability and tensile properties was investigated. The electrical properties of the IC CANs were studied by impedance spectroscopy at various temperatures. Their ionic conductivity was analyzed by the Vogel–Tamman–Fulcher model and equivalent‐circuit fitting. Due to the high mobility of charge carriers, the IC CAN sample (containing15 wt% LiTFSI) exhibited the best ionic conductivity, which reached a value of 3.35 × 10−6 S cm−1 at 80 °C and 8.31 × 10−6 S cm−1 at 100 °C, presenting great attraction for self‐healing iontronics.

Lead electrodeposition from aliphatic polyamines solutions

Hydrometallurgical and pyrometallurgical processing of ores and concentrates generates large amount of various solid residues. These may contain significant amount of heavy metals, particularly lead is of great importance. It is present in form of anglesite, cerrusite or lead oxides. Hydrometallurgical processing of leaching residues, dusts, and fly ashes is used to recover valuable metals from these streams. Acid leaching in sulfuric acid solutions or spent electrolyte results in producing high amount of lead sulfate that is still very attractive material to fulfill demand of lead acid battery market. Aliphatic linear polyamines are solvent extracting agents very selective towards lead sulfate. Here we report the comparative tests of four different linear aliphatic homologs, namely ethylenediamine, diethylenetriamine, triethylenetetramine, and tetraethylenepentamine as potential extracting agents of lead sulfate. The core research was devoted to the possibility of direct electrodeposition of lead from various polyamines solutions. Electrochemical tests performed at current density 200 A/m2, 60 °C, with an addition of selected inhibitor showed the possibility to produce metal layer with 97.2% purity for triethylenetetramine.Graphical abstract

Open-label use of an aliphatic polyamine immunomodulator in patients hospitalized with COVID-19.

BackgroundEvidence-based therapies used to treat coronavirus disease (COVID-19) remain limited. Azoximer bromide (AZB; Polyoxidonium®) is an immunomodulating molecule frequently used in the Russian Federation. It offers demonstrable therapeutic benefit in upper respiratory tract infections. This study evaluated the safety and efficacy of AZB when used in combination with standard of care treatment in patients hospitalized with COVID-19.MethodsHospitalized patients with COVID-19 (n=81; nine sites) received AZB 12 mg intravenously once daily for 3 days then intramuscularly every other day until day 17. The primary endpoint included clinical status at day 15 versus baseline. Historical control data of 100 patients from a randomized, controlled, open-label trial conducted in China were included to serve as a direct control group.ResultsNotable clinical improvement, assessed by seven-point ordinal scale (OS) score and National Early Warning Score, was observed. Mean duration of hospitalization was 19.3 days. Indicators of pneumonia and lung function showed gradual recovery to normalization. No patients died but, by day 28, one patient still required respiratory support; this patient died on day 34. A higher proportion of patients receiving AZB required invasive or non-invasive ventilation (OS 5 or 6) at baseline compared with the historical control group. Improvement in mean OS score by day 14/15 was not notable in the control group (OS 3.99–3.87) but was clear in the AZB group (OS 4.36–2.90). Mean duration of hospitalization was similar in the control group (16.0 days); however, day 28 mortality was higher, at 25.0% (n=25).ConclusionAZB combined with standard of care was safe and well tolerated. An apparent clinical improvement could not be fully evaluated due to the lack of a direct control group; further assessment of AZB for the treatment of COVID-19 in a randomized, placebo-controlled study is warranted.

New approaches related to the use of polyamine-free and polyamine-deficient diets in the list of nutritional products for COVID-19 patients

Researches aimed at finding effective means of pathogenic therapy for this viral infection are extremely relevant. Researches of the last three years have established that some human pathogenic coronaviruses – MERS, SARS-CoV and SARS-CoV-2, contain aliphatic polyamines in their structure, which participate in the packaging of genetic material (DNA, RNA), as well as the nucleocapsid. Virus-host cell interactions also provide adhesion processes on the surface of the cytoplasmic membrane of target cells. In the intracellular space, aliphatic polyamines actively affect the translation and replication processes of the genetic material and necessary proteins of the virus itself, as well as the formation of daughter viruses. Long-term persistence in the SARS-CoV-2 infected organism is largely due to the absorption of polyamines by coronavirus localized in target cells of the blood and parenchymatous organs. Unfortunately, the above new facts did not serve as a prerequisite for finding effective means of pathogenetic therapy for COVID-19, based on the inhibition of polyamine-dependent processes that ensure long-term persistence of SARS-CoV-2 in the infected organism. We are talking about specific drugs such as α-difluoromethylornithine and its analogues, which are successfully used in oncology in the complex treatment of malignant neoplasms with the aim of lowering the level of aliphatic polyamines in the affected areas of malignantly transformed organs. We recommend the use of polyamine-free and polyamine-deficient diets for COVID-19 for the first time. In the planned study, we will present tables with food products of animal and vegetable origin, characterized by extremely low content and/or absence of aliphatic polyamines in them. At the same time, food products with a high content of aliphatic polyamines should be excluded from the general list of products recommended for COVID-19 patients. We also recommend the use of a polyamine-deficient diet (with a preventive purpose) during the COVID-19 pandemic to a wide contingent of practically healthy individuals, convalescents, medical staff of specialized infectious disease clinics, as well as family members of SARS-CoV-2 infected patients.

Potential significance of aliphatic polyamines, α-synucleins and Helicobacter Pylori in diagnostics and prognosis of some malignant tumors.

Polyamines (putrescine, spermidine and spermine) as well as γ- and α-synucleins are currently the subject of a special comprehensive study due to their direct influence on the formation of neoplastic processes. This review article presents informative data on the role of aliphatic polyamines (putrescine, spermidine, spermine) in the induction of a number of oncological diseases with their localization in the digestive and urinary systems. Aspects related to the synthesis and aggregation of γ-synucleins into malignantly reborn cells have been discussed. The article provides information on the possible prevention of further growth of malignant cells, by inhibiting enzymatic processes responsible for the polyamine synthesis. In case of prolonged persistence of Helicobacter Pylori in the stomach, an enhanced synthesis of polyamines and cumulation in situ of oligo- and aggregated gamma synucleins occurs in mucous membrane cells. It is possible that all of the abovementioned factors in total directly and/or indirectly have a stimulating effect on the processes of the malignancy of gastric mucosal cells. The subject of special discussion was the latest literature data, according to which, under the conditions of Helicobacter Pylori persistence in the digestive tract organs, in the gastric mucosal cells an enhanced synthesis of putrescine occurs, high concentrations of which can have a co-carcinogenic effect on normally functioning target cells. From a qualitatively new point of view, the fact of cumulation in malignantly reborn cells of an aggregated gamma synuclein, which was found during Helicobacter Pylori infection, should be considered.

Hydroxycinnamate Amides: Intriguing Conjugates of Plant Protective Metabolites.

The syntheses of aromatic monoamines and aliphatic polyamines (PAs) are responsive to environmental stresses, with some modulating aspects of plant defense. Conjugation of amines to hydroxycinnamic acids (HCAs) generates HCA amides (HCAAs), with the conjugates possessing properties from both compounds. Conjugation may reduce the polarity of the resulting metabolite and assist in translocation, stability, and compartmentalization. Recent metabolomic insights identified HCAAs as biomarkers during plant-pathogen interactions, supporting a functional role in defense. The conjugates may contribute to regulation of the dynamic metabolic pool of hydroxycinnamates. This review highlights the occurrence of aromatic amines (AAs) and PAs in stress metabolism, conjugation to HCAs, and the roles of HCAAs during host defense, adding emphasis on their involvement in hydrogen peroxide (H2O2) production and cell-wall strengthening.

Thermal and Fire Behavior of a Bio-Based Epoxy/Silica Hybrid Cured with Methyl Nadic Anhydride.

Thermosetting polymers have been widely used in many industrial applications as adhesives, coatings and laminated materials, among others. Recently, bisphenol A (BPA) has been banned as raw material for polymeric products, due to its harmful impact on human health. On the other hand, the use of aromatic amines as curing agents confers excellent thermal, mechanical and flame retardant properties to the final product, although they are toxic and subject to governmental restrictions. In this context, sugar-derived diepoxy monomers and anhydrides represent a sustainable greener alternative to BPA and aromatic amines. Herein, we report an “in-situ” sol–gel synthesis, using as precursors tetraethylorthosilicate (TEOS) and aminopropyl triethoxysilane (APTS) to obtain bio-based epoxy/silica composites; in a first step, the APTS was left to react with 2,5-bis[(oxyran-2-ylmethoxy)methyl]furan (BOMF) or diglycidyl ether of bisphenol A (DGEBA)monomers, and silica particles were generated in the epoxy in a second step; both systems were cured with methyl nadic anhydride (MNA). Morphological investigation of the composites through transmission electron microscopy (TEM) demonstrated that the hybrid strategy allows a very fine distribution of silica nanoparticles (at nanometric level) to be achieved within a hybrid network structure for both the diepoxy monomers. Concerning the fire behavior, as assessed in vertical flame spread tests, the use of anhydride curing agent prevented melt dripping phenomena and provided high char-forming character to the bio-based epoxy systems and their phenyl analog. In addition, forced combustion tests showed that the use of anhydride hardener instead of aliphatic polyamine results in a remarkable decrease of heat release rate. An overall decrease of the smoke parameters, which is highly desirable in a context of greater fire safety was observed in the case of BOMF/MNA system. The experimental results suggest that the effect of silica nanoparticles on fire behavior appears to be related to their dispersion degree.

Metatranscriptomic identification of polyamine-transforming bacterioplankton in the Gulf of Mexico.

The importance of short-chained aliphatic polyamines (PAs) to bacterioplankton-mediated carbon and nitrogen cycles has been repeatedly proposed. However, bacterial taxa and genes involved in the transformations of different PA compounds and their potential spatial variations remain unclear. This study collected surface bacterioplankton from nearshore, offshore, and open ocean stations in the Gulf of Mexico and examined how metatranscriptomes responded to additions of three single PA model compounds (i.e. putrescine, spermidine, or spermine). Our data showed an overrepresentation of genes affiliated with γ-glutamylation and spermidine cleavage pathways in metatranscriptomes received PA amendments and the expression level of each pathway varied among different PA compounds and sampling locations. PA-transforming taxa were affiliated with Actinobacteria, Bacteroidetes, Cyanobacteria, Planctomycetes, and Proteobacteria and their relative importance was also compound and location specific. These findings suggest that PAs are transformed via multiple pathways and by a diversity of marine bacterioplankton in the Gulf of Mexico. The relative importance of different PA transforming pathways and composition of functional microbial communities may be regulated by nutrient status of local environments.