Showing papers in "Amino Acids in 2020"
TL;DR: Dietary taurine, creatine, carnosine, anserine,Anserine and 4-hydroxyproline are beneficial for preventing and treating obesity, cardiovascular dysfunction, and ageing-related disorders, as well as inhibiting tumorigenesis, improving skin and bone health, ameliorating neurological abnormalities, and promoting well being in infants, children and adults.
Abstract: Taurine (a sulfur-containing β-amino acid), creatine (a metabolite of arginine, glycine and methionine), carnosine (a dipeptide; β-alanyl-l-histidine), and 4-hydroxyproline (an imino acid; also often referred to as an amino acid) were discovered in cattle, and the discovery of anserine (a methylated product of carnosine; β-alanyl-1-methyl-l-histidine) also originated with cattle. These five nutrients are highly abundant in beef, and have important physiological roles in anti-oxidative and anti-inflammatory reactions, as well as neurological, muscular, retinal, immunological and cardiovascular function. Of particular note, taurine, carnosine, anserine, and creatine are absent from plants, and hydroxyproline is negligible in many plant-source foods. Consumption of 30 g dry beef can fully meet daily physiological needs of the healthy 70-kg adult human for taurine and carnosine, and can also provide large amounts of creatine, anserine and 4-hydroxyproline to improve human nutrition and health, including metabolic, retinal, immunological, muscular, cartilage, neurological, and cardiovascular health. The present review provides the public with the much-needed knowledge of nutritionally and physiologically significant amino acids, dipeptides and creatine in animal-source foods (including beef). Dietary taurine, creatine, carnosine, anserine and 4-hydroxyproline are beneficial for preventing and treating obesity, cardiovascular dysfunction, and ageing-related disorders, as well as inhibiting tumorigenesis, improving skin and bone health, ameliorating neurological abnormalities, and promoting well being in infants, children and adults. Furthermore, these nutrients may promote the immunological defense of humans against infections by bacteria, fungi, parasites, and viruses (including coronavirus) through enhancing the metabolism and functions of monocytes, macrophages, and other cells of the immune system. Red meat (including beef) is a functional food for optimizing human growth, development and health.
206 citations
TL;DR: The results indicate the unique importance of animal-source feedstuffs in improving the feed efficiency, growth and health of animals (including fish and companion animals) and the findings also have important implications for human nutrition.
Abstract: We analyzed the composition of amino acids (AAs) in oligopeptides, proteins, and the free pool, as well as creatine, agmatine, polyamines, carnosine, anserine, and glutathione, in animal- and plant-derived feedstuffs. Ingredients of animal origins were black soldier fly larvae meal (BSFM), chicken by-product meal, chicken visceral digest, feather meal, Menhaden fishmeal, Peruvian anchovy fishmeal, Southeast Asian fishmeal, spray-dried peptone from enzymes-treated porcine mucosal tissues, poultry by-product meal (pet-food grade), spray-dried poultry plasma, and spray-dried egg product. Ingredients of plant origins were algae spirulina meal, soybean meal, and soy protein concentrate. All animal-derived feedstuffs contained large amounts of all proteinogenic AAs (particularly glycine, proline, glutamate, leucine, lysine, and arginine) and key nonproteinogenic AAs (taurine and 4-hydroxyproline), as well as significant amounts of agmatine, polyamines, creatine, creatinine, creatine phosphate, and glutathione. These nitrogenous substances are essential to either DNA and protein syntheses in cells or energy metabolism in tissues (particularly the brain and skeletal muscle). Of note, chicken by-product meal, poultry by-product meal, and spray-dried poultry plasma contained large amounts of carnosine and anserine (potent antioxidants). Compared with most of the animal-derived feedstuffs, plant-derived feedstuffs contained much lower contents of glycine and proline, little 4-hydroxyproline, and no creatine, creatinine, creatine phosphate, carnosine or anserine. These results indicate the unique importance of animal-source feedstuffs in improving the feed efficiency, growth and health of animals (including fish and companion animals). Because soy protein concentrate is consumed by infants, children and adults, as are BSFM and algae for children and adults, our findings also have important implications for human nutrition.
100 citations
TL;DR: This review focuses on polyamines in macrophage activation patterns in the context of gastrointestinal inflammation and carcinogenesis and seeks to clarify mechanisms of innate immune regulation by polyamine metabolism and potential novel therapeutic targets.
Abstract: Naturally occurring polyamines are ubiquitously distributed and play important roles in cell development, amino acid and protein synthesis, oxidative DNA damage, proliferation, and cellular differentiation. Macrophages are essential in the innate immune response, and contribute to tissue remodeling. Naive macrophages have two major potential fates: polarization to (1) the classical pro-inflammatory M1 defense response to bacterial pathogens and tumor cells, and (2) the alternatively activated M2 response, induced in the presence of parasites and wounding, and also implicated in the development of tumor-associated macrophages. ODC, the rate-limiting enzyme in polyamine synthesis, leads to an increase in putrescine levels, which impairs M1 gene transcription. Additionally, spermidine and spermine can regulate translation of pro-inflammatory mediators in activated macrophages. In this review, we focus on polyamines in macrophage activation patterns in the context of gastrointestinal inflammation and carcinogenesis. We seek to clarify mechanisms of innate immune regulation by polyamine metabolism and potential novel therapeutic targets.
79 citations
TL;DR: Dietary supplementation with Glu and Gln to farmed fish can improve their growth performance, intestinal development, innate and adaptive immune responses, skeletal muscle development and fillet quality, ammonia removal, and the endocrine status.
Abstract: Glutamate (Glu) and glutamine (Gln) comprise a large proportion of total amino acids (AAs) in fish in the free and protein-bound forms. Both Glu and Gln are synthesized de novo from other α-amino acids and ammonia. Although these two AAs had long been considered as nutritionally non-essential AAs for an aquatic animal, they must be included adequately in its diet to support optimal health (particularly intestinal health) and maximal growth. In research on fish nutrition, Glu has been used frequently as an isonitrogenous control on the basis of the assumption that this AA has no nutritional or physiological function. In addition, purified diets used for feeding fish generally lack glutamine. As functional AAs, Glu and Gln are major metabolic fuels for tissues of fish (including the intestine, liver, kidneys, and skeletal muscle), and play important roles not only in protein synthesis but also in glutathione synthesis and anti-oxidative reactions. The universality of Glu and Gln as abundant intracellular AAs depends on their enormous versatility in metabolism. Dietary supplementation with Glu and Gln to farmed fish can improve their growth performance, intestinal development, innate and adaptive immune responses, skeletal muscle development and fillet quality, ammonia removal, and the endocrine status. Glu (mainly as monosodium glutamate), glutamine, or AminoGut (a mixture of Glu and Gln) is a promising feed additive to reduce the use of fishmeal, while gaining the profitability of global aquaculture production. Thus, the concept of dietary requirements of fish for Glu and Gln is a paradigm shift in the nutrition of aquatic animals (including fish).
62 citations
TL;DR: The impact of NPAA incorporation can be extremely beneficial in improving the stability, potency, permeability, and bioavailability of peptide-based therapies, and undesired effects such as toxicity or immunogenicity should also be considered.
Abstract: With the development of modern chemistry and biology, non-proteinogenic amino acids (NPAAs) have become a powerful tool for developing peptide-based drug candidates. Drug-like properties of peptidic medicines, due to the smaller size and simpler structure compared to large proteins, can be changed fundamentally by introducing NPAAs in its sequence. While peptides composed of natural amino acids can be used as drug candidates, the majority have shown to be less stable in biological conditions. The impact of NPAA incorporation can be extremely beneficial in improving the stability, potency, permeability, and bioavailability of peptide-based therapies. Conversely, undesired effects such as toxicity or immunogenicity should also be considered. The impact of NPAAs in the development of peptide-based therapeutics is reviewed in this article. Further, numerous examples of peptides containing NPAAs are presented to highlight the ongoing development in peptide-based therapeutics.
55 citations
TL;DR: Dietary lipid and starch levels are recommended to be 10% and < 10%, respectively, for juvenile LMB to maximize the retention of dietary protein in their bodies.
Abstract: Protein accretion in some fish species is affected by dietary lipids, starch and their interactions, but this aspect of nutrition is largely unknown in largemouth bass (LMB). Therefore, we designed six experimental diets with three starch levels (5%, 10%, and 15%; dry matter basis) and two lipid levels (10% and 12.5%; dry matter basis) to evaluate the effects of dietary starch and lipid levels on the protein retention, growth, feed utilization, and liver histology of LMB. There were three tanks (18 fish per tank, ~ 4.85 g per fish) per dietary treatment group and the trial lasted for 8 weeks. Fish were fed to apparent satiation twice daily. Results indicated that increasing the dietary starch level from 5 to 15% reduced (P < 0.05) absolute feed intake (AFI; − 9.0%, − 15% and − 14% on days 14–28, 28–42, and 42–56, respectively) and weight gains (− 4.4% and − 6.5% on days 42 and 56, respectively) of LMB. Increasing the dietary lipid level from 10 to 12.5% reduced (P < 0.05) AFI (− 9.7%, − 11.7% and − 11.9% on days 14–28, 28–42; and 42–56, respectively), weight gains (− 4.2%, − 5.9% and − 6.9% on days 28, 42 and 56, respectively), and survival rate (by a 5.6% unit) of LMB. The retention of dietary protein and some amino acids in the body was affected by dietary starch or lipid levels and their interactions. The viscerosomatic index (VSI), hepatosomatic index (HSI), and intraperitoneal fat ratio (IPFR) increased with increasing the dietary starch level from 5 to 15%. Compared with 10% lipids, 12.5% lipids in diets increased IPFR but had no effect on VSI or HSI. The concentrations of glucose in serum increased with increasing the dietary starch level from 5 to 15% at 4 to 24 h after feeding, with the effect of dietary lipids being time-dependent. Compared with a 5%-starch diet, fish fed a diet with 10%- or 15%-starch exhibited an enlarged and pale liver with excessive glycogen. Based on these findings, we recommend dietary lipid and starch levels to be 10% and < 10%, respectively, for juvenile LMB to maximize the retention of dietary protein in their bodies.
42 citations
TL;DR: The hypothesis was that intestinal SARS-CoV-2 receptor ACE2 expression depends on patients’ age, and the higher intestinal ACE2 mRNA expression in older patients may impact on their susceptibility to develop intestinal symptoms.
Abstract: Gastrointestinal symptoms are common in COVID-19 patients, especially in younger patients. Our hypothesis was that intestinal SARS-CoV-2 receptor ACE2 expression depends on patients' age. We examined duodenal biopsies from 43 healthy human adults. ACE2 gene expression was directly correlated with age (Spearman's r = 0.317, p = 0.039). With each year, duodenal ACE2 expression increased by 0.083 RU. The higher intestinal ACE2 mRNA expression in older patients may impact on their susceptibility to develop intestinal symptoms.
39 citations
TL;DR: The beneficial effects of agmatine for treating depression, anxiety, neuropathic pain, cognitive decline and learning impairment, dependence on drugs, and metabolic diseases (diabetes and obesity), since these fields have been intensively investigated are summarized.
Abstract: Agmatine, a natural polyamine produced from arginine by arginine decarboxylase, was first discovered in 1910, but its physiological significance was disregarded for a century. The recent rediscovery of agmatine as an endogenous ligand for α2-adrenergic and imidazoline receptors in the mammalian brain suggests that this amine may be a promising therapeutic agent for treating a broad spectrum of central nervous system-associated diseases. In the past two decades, numerous preclinical and several clinical studies have demonstrated its pleiotropic modulatory functions on various molecular targets related to neurotransmission, nitric oxide synthesis, glucose metabolism, polyamine metabolism, and carnitine biosynthesis, indicating potential for therapeutic applications and use as a nutraceutical to improve quality of life. An enzymatic activity of arginine decarboxylase which produces agmatine from arginine was low in mammals, suggesting that a large portion of the agmatine is supplemented from diets and gut microbiota. In the present review, we focus on and concisely summarize the beneficial effects of agmatine for treating depression, anxiety, neuropathic pain, cognitive decline and learning impairment, dependence on drugs, and metabolic diseases (diabetes and obesity), since these fields have been intensively investigated. We also briefly discuss agmatine content in foodstuffs, and a simple approach for enhancing agmatine production using the filamentous fungus Aspergillus oryzae, widely used for the production of various Asian fermented foods.
30 citations
TL;DR: Six isocaloric diets were designed to determine the effects of different dietary crude protein and lipid levels on fat and glycogen deposits, as well as hepatosis in largemouth bass, and recommend dietary CP and lipids levels to be 45% and 10%, respectively, for juvenile LMB.
Abstract: The reported requirements of largemouth bass (LMB, which is native to North America) for dietary protein and lipids varied substantially among previous studies, and this fish fed current formulated diets exhibit poor growth performance and pale liver syndrome. Because amino acids and lipids are known to affect hepatic metabolism and function in mammals, it is imperative to understand the impacts of these dietary macronutrients on the growth and liver morphology of LMB. In this study, we designed six isocaloric diets to determine the effects of different dietary crude protein (CP; 40%, 45%, and 50%; dry matter basis) and lipid levels (7.5% and 10%; dry matter basis) on fat and glycogen deposits, as well as hepatosis in LMB. There were four tanks (12 fish per tank, an average initial weight of 18.4 g/fish) per dietary treatment group and the trial lasted for 8 weeks. Fish were fed to apparent satiation three times daily. Results indicated that LMB fed the 45% or 50% CP diet grew faster (P < 0.05), had less (P < 0.05) glycogen in the liver and smaller (P < 0.05) hepatocyte sizes than fish fed the 40% CP diet, but there was no difference in weight gain or feed efficiency between the 45% and 50% CP diets. The hepatic lipid content did not differ between LMB fed the 40% and 45% CP diets, and the values for these two groups were 29% lower (P < 0.05) than those for LMB fed the 50% CP diet. Compared with the 40% CP group, LMB fed the 45% or 50% CP diet had 8–12% lower content of total minerals, phosphorus, and calcium in the body. Increasing the dietary lipid level from 7.5 to 10% enhanced the weight gains (+ 15%) and feed efficiency (+ 22%), as well as the retention of dietary protein (+ 18%), energy (+ 25%), and phosphorus (+ 7.6%) in the body. No fatty liver occurred in any group of LMB (with hepatic lipid concentrations being < 2%, wet weight basis). Based on these growth, metabolic and histologic data, we recommend dietary CP and lipids levels to be 45% and 10%, respectively, for juvenile LMB.
27 citations
TL;DR: It is found that healthy dietary patterns were associated with a preference for polyamine-rich foods, and increased polyamine intake extended the lifespan of mice and decreased the incidence of colon cancer induced by repeated administration of moderate amounts of a carcinogen.
Abstract: The polyamines spermidine and spermine are synthesized in almost all organisms and are also contained in food. Polyamine synthesis decreases with aging, but no significant decrease in polyamine concentrations were found in organs, tissues, and blood of adult animals and humans. We found that healthy dietary patterns were associated with a preference for polyamine-rich foods, and first reported that increased polyamine intake extended the lifespan of mice and decreased the incidence of colon cancer induced by repeated administration of moderate amounts of a carcinogen. Recent investigations have revealed that changes in DNA methylation status play an important role in lifespan and aging-associated pathologies. The methylation of DNA is regulated by DNA methyltransferases in the presence of S-adenosylmethionine. Decarboxylated S-adenosylmethionine, converted from S-adenosylmethionine by S-adenosylmethionine decarboxylase, provides an aminopropyl group to synthesize spermine and spermidine and acts to inhibit DNMT activity. Long-term increased polyamine intake were shown to elevate blood spermine levels in mice and humans. In vitro studies demonstrated that spermine reversed changes induced by the inhibition of ornithine decarboxylase (e.g., increased decarboxylated S-adenosylmethionine, decreased DNA methyltransferase activity, increased aberrant DNA methylation), whose activity decreases with aging. Further, aged mice fed high-polyamine chow demonstrated suppression of aberrant DNA methylation and a consequent increase in protein levels of lymphocyte function-associated antigen 1, which plays a pivotal role on inflammatory process. This review discusses the relation between polyamine metabolism and DNA methylation, as well as the biological mechanism of lifespan extension induced by increased polyamine intake.
24 citations
TL;DR: Results indicated that the liver and skeletal muscle had a limited ability to oxidize glucose and palmitate to CO2 for ATP production in the presence of individual or a mixture of substrates due to low activities of carnitine palmitoyltransferase-I, hexokinase and pyruvate dehydrogenase.
Abstract: This study tested the hypothesis that amino acids are oxidized at higher rates than glucose and palmitate for ATP production in tissues of largemouth bass (LMB, a carnivorous fish). Slices (10 to 50 mg) of liver, proximal intestine, kidney, and skeletal muscle isolated from LMB were incubated at 26 °C for 2 h in oxygenated Krebs–Henseleit bicarbonate buffer (pH 7.4, with 5 mM d-glucose) containing either d-[U-14C]glucose, 2 mM l-alanine plus l-[U-14C]alanine, 2 mM l-aspartate plus l-[U-14C]aspartate, 2 mM l-glutamate plus l-[U-14C]glutamate, 2 mM l-glutamine plus l-[U-14C]glutamine, 2 mM l-leucine plus l-[U-14C]leucine, or 2 mM palmitate plus [U-14C]palmitate. In parallel experiments, tissues were incubated with a [U-14C]-labeled tracer and a mixture of unlabeled substrates [alanine, aspartate, glutamate, glutamine, leucine, and palmitate (2 mM each) plus 5 mM glucose]. 14CO2 was collected to calculate the rates of substrate oxidation. In separate experiments, O2 consumption by each tissue was measured in the presence of individual or a mixture of substrates. The activities of key metabolic enzymes were also measured. Results indicated that the liver and skeletal muscle had a limited ability to oxidize glucose and palmitate to CO2 for ATP production in the presence of individual or a mixture of substrates due to low activities of carnitine palmitoyltransferase-I, hexokinase and pyruvate dehydrogenase. In the presence of individual substrates, each amino acid was actively oxidized by all the tissues. In the presence of a mixture of substrates, glutamine and glutamate were the major metabolic fuels in the proximal intestine and kidney, as glutamine for the liver and aspartate for skeletal muscle. All the tissues had high activities of glutaminase, glutamate dehydrogenase, and transaminases. At the same extracellular concentration of amino acids (2 mM) in a mixture of energy substrates, glutamine was the major metabolic fuel for the liver of the LMB, glutamine and glutamate for the proximal intestine and kidneys, and aspartate for the skeletal muscle. Glutamine plus glutamate plus aspartate generated 60–70% of ATP in LMB tissues.
TL;DR: This article provides reference to analytical methods for amino acids in organisms for food and human research, which include thin-layer chromatography, high-performance liquid Chromatography, liquid chromatography-mass spectrometer, gas Chromatography- mass spectrometry, capillary electrophoresis, nuclear magnetic resonance, and amino acid analyzer analysis.
Abstract: Amino acids are important metabolites for tissue metabolism, growth, maintenance, and repair, which are basic life necessities. Therefore, summarizing analytical methods for amino acid determination in organisms is important. In the past decades, analytical methods for amino acids have developed rapidly but have not been fully explored. Thus, this article provides reference to analytical methods for amino acids in organisms for food and human research. Present amino acid analysis methods include thin-layer chromatography, high-performance liquid chromatography, liquid chromatography-mass spectrometer, gas chromatography-mass spectrometry, capillary electrophoresis, nuclear magnetic resonance, and amino acid analyzer analysis.
TL;DR: It is demonstrated that peptides from chia seeds may contribute in the improvement of skin health by offering protection against aging-related enzymes by preventing degradation of the protein matrix on the skin; however, further in vivo studies are needed to evaluate its actual capability.
Abstract: Chia (Salvia hispanica) seed peptides have drawn attention because of their antioxidant, antihypertensive and anti-inflammatory activities, making them ideal candidates for development of cosmeceutical skin products. However, there are no preceding reports that address their aging-related enzyme inhibitory activities. The aim of this study was to investigate the in vitro and in silico inhibitory activity of chia seed peptides towards the main aging-related enzymes. Enzyme-inhibition activity of < 3 kDa chia seed peptides towards collagenase, hyaluronidase, tyrosinase, and elastase was evaluated. Further fractions were obtained by size exclusion chromatography (SEC) and re-tested for enzyme inhibitory activity. Peptide sequences were identified from the most effective fraction and used for in silico analysis. The < 3 kDa peptides exhibited inhibitory activities towards elastase (65.32%, IC50 = 0.43 mg/mL), tyrosinase (58.74%, IC50 = 0.66 mg/mL), hyaluronidase (26.96%, IC50 = 1.28 mg/mL), and collagenase (28.90%, IC50 = 1.41 mg/mL). They showed mixed-type inhibition patterns towards elastase and hyaluronidase, while a non-competitive inhibition pattern was observed towards collagenase and tyrosinase. Fraction II obtained by SEC, showed higher enzyme inhibitory activity. Seven peptides were identified in this fraction (APHWYTN, DQNPRSF, GDAHWAY, GDAHWTY, GDAHWVY, GFEWITF, and KKLKRVYV), which according to in silico analysis, possess 19–29 enzyme–peptide pair interactions towards elastase and three peptide sequences shared homology sequence (GDAHW). These results demonstrate that peptides from chia seeds may contribute in the improvement of skin health by offering protection against aging-related enzymes by preventing degradation of the protein matrix on the skin; however, further in vivo studies are needed to evaluate its actual capability.
TL;DR: This review article profiles 13 new tailor-made AA-derived pharmaceuticals introduced to the market in 2019, and discusses the development form drug-candidates, total synthesis, with emphasis on the core-AA, therapeutic area, and the mode of biological activity.
Abstract: Amino acids (AAs) are among a handful of paramount classes of compounds innately involved in the origin and evolution of all known life-forms. Along with basic scientific explorations, the major goal of medicinal chemistry research in the area of tailor-made AAs is the development of more selective and potent pharmaceuticals. The growing acceptance of peptides and peptidomimetics as drugs clearly indicates that AA-based molecules become the most successful structural motif in the modern drug design. In fact, among 24 small-molecule drugs approved by FDA in 2019, 13 of them contain a residue of AA or di-amines or amino-alcohols, which are commonly considered to be derived from the parent AAs. In the present review article, we profile 13 new tailor-made AA-derived pharmaceuticals introduced to the market in 2019. Where it is possible, we will discuss the development form drug-candidates, total synthesis, with emphasis on the core-AA, therapeutic area, and the mode of biological activity.
TL;DR: The manuscripts included in this special issue range from biochemistry to pharmacology, chemistry, genetics, molecular biology and clinical science on the current state of knowledge regarding the physiological, biochemical, and therapeutic actions of polyamines, and should be of use to the old and the new generation of researchers in the polyamine field.
Abstract: The history of polyamines dates back to the fifteenth century when spermine was discovered by Antonie van Leeuwenhoek [born in Delft, Holland (1632–1723)], but it took several decades before scientists got interested in understanding and unraveling the role(s) of spermine and other polyamines in the biology of living cells. Mammalian cells contain significant amounts of polyamines and these molecules, which are polycations, play specific roles in various tissues. Although the physiological functions of these polycations have yet to be elucidated completely at the molecular level, many studies have provided a better understanding of the roles polyamines play in cell growth, proliferation, and pathophysiological processes. At the 5th International Conference on Polyamines: Biochemical, Physiological and Clinical Perspectives held in Taiwan, in 2018, special attention has been given to the role of polyamines in carcinogenesis and in developing new approaches for cancer therapy and other diseases. The issue is a tribute and dedicated by internationally recognized experts to the memory of Professor Seymour S. Cohen, a prominent scientist in polyamine research. The manuscripts included in this special issue range from biochemistry to pharmacology, chemistry, genetics, molecular biology and clinical science on the current state of knowledge regarding the physiological, biochemical, and therapeutic actions of polyamines, and should be of use to the old and the new generation of researchers in the polyamine field. Editorial
TL;DR: Fivesynaptosome isolation methods are examined by the means of electron microscopy, Western blot, and liquid chromatography-mass spectrometry to compare their efficiency in the isolation of synaptosomes and depletion of contaminating subcellular structures to suggest that in selecting the appropriate isolation method for any neuroproteomics experiment carried out on synaptoomes, the degree and sort/source of contamination should be considered as a primary aspect.
Abstract: Synaptosomes are frequently used research objects in neurobiology studies focusing on synaptic transmission as they mimic several aspects of the physiological synaptic functions. They contain the whole apparatus for neurotransmission, the presynaptic nerve ending with synaptic vesicles, synaptic mitochondria and often a segment of the postsynaptic membrane along with the postsynaptic density is attached to its outer surface. As being artificial functional organelles, synaptosomes are viable for several hours, retain their activity, membrane potential, and capable to store, release, and reuptake neurotransmitters. Synaptosomes are ideal subjects for proteomic analysis. The recently available separation and protein detection techniques can cope with the reduced complexity of the organelle and enable the simultaneous qualitative and quantitative analysis of thousands of proteins shaping the structural and functional characteristics of the synapse. Synaptosomes are formed during the homogenization of nervous tissue in the isoosmotic milieu and can be isolated from the homogenate by various approaches. Each enrichment method has its own benefits and drawbacks and there is not a single method that is optimal for all research purposes. For a proper proteomic experiment, it is desirable to preserve the native synaptic structure during the isolation procedure and keep the degree of contamination from other organelles or cell types as low as possible. In this article, we examined five synaptosome isolation methods from a proteomic point of view by the means of electron microscopy, Western blot, and liquid chromatography-mass spectrometry to compare their efficiency in the isolation of synaptosomes and depletion of contaminating subcellular structures. In our study, the different isolation procedures led to a largely overlapping pool of proteins with a fairly similar distribution of presynaptic, active zone, synaptic vesicle, and postsynaptic proteins; however, discrete differences were noticeable in individual postsynaptic proteins and in the number of identified transmembrane proteins. Much pronounced variance was observed in the degree of contamination with mitochondrial and glial structures. Therefore, we suggest that in selecting the appropriate isolation method for any neuroproteomics experiment carried out on synaptosomes, the degree and sort/source of contamination should be considered as a primary aspect.
TL;DR: It is indicated that taurine supplementation (3000 mg/day) for 8 weeks could improve the glycemic indexes and lipid profiles including TC and LDL-C in the patients with T2DM.
Abstract: Previous studies have suggested that taurine has hypoglycemic and hypolipidemic effects on experimental diabetic models. Therefore, this clinical trial was designed to explore the impacts of taurine supplementation on glycemic control and lipid profile in the patients with T2DM. This study was conducted on 45 patients with T2DM in Tabriz Sheikhor-raees Polyclinic and Imam-Reza Hospital Endocrine Center. Subjects were randomly divided into taurine and placebo groups. Accordingly, the taurine group (n = 23) received taurine 3000 mg/daily and the placebo group (n = 22) took crystalline microcellulose/daily for the duration of 8 weeks. At baseline and after the trial completion, fasting blood samples were obtained from the patients to assess the glycemic indicators and lipid profile. Independent t test, paired t test, Pearson’s correlation, and analysis of covariance was used for analysis. At the end of the study, levels of FBS (p = 0.01), insulin (p = 0.01), HOMA-IR (p = 0.003), TC (p = 0.013), and LDL-C (p = 0.041) significantly decreased in the taurine group compared to the placebo group. In addition, there was no significant changes in HbA1c, triglyceride, HDL-C, anthropometric indicators or dietary intakes by passing 8 weeks from the intervention. In conclusion, the findings of the current study indicated that taurine supplementation (3000 mg/day) for 8 weeks could improve the glycemic indexes and lipid profiles including TC and LDL-C in the patients with T2DM.
TL;DR: The results from the present study demonstrate that the movement of the amino acids into the carriers is spontaneous and forms stable complexes in graphene-amino acid interaction.
Abstract: Graphene-amino acid interaction is gaining significance mainly based on its possible biomedicine applications. The density functional theory (DFT) calculation and molecular dynamics simulation (MD) are applied to obtain a comprehensive understanding of the adsorption mechanism of three kinds of amino acids, namely, alanine (Ala), glycine (Gly), and valine (Val) over the surface of graphene and functionalized graphene nanosheets. In this study, several analyses such as solvation energy, adsorption energy, intermolecular distances, and charge properties are used to explore the adsorption behavior of amino acid on the nanosheets. The calculated adsorption energies show that the interaction of amino acids with functionalized graphene is greater than the pristine graphene. Regarding DFT computations, the adsorption of Val on the graphene about - 10 kJ/mol is stronger than Gly and Ala. Meanwhile, it is found that the geometrical parameters and electronic properties of graphene change drastically upon functionalization, and the formation of hydrogen bonds between -COOH functional group and amino acids enhances the adsorption energy about 12-30%. To obtain a deeper comprehension of the interaction nature, the atoms in molecules (AIM) and the natural bond orbital (NBO) studies have been performed. Furthermore, the MD simulations are employed to assess the dynamic properties of our designed systems. The results from the present study demonstrate that the movement of the amino acids into the carriers is spontaneous and forms stable complexes.
TL;DR: In vitro antibacterial activity against S. aureus and MRSA revealed that liposomes had enhanced activity at pH 6 compared to pH 7.4 and the formulation can potentially be used to enhance activity and penetration of AMPs, thereby improving the treatment of bacterial infections.
Abstract: Antimicrobial peptides (AMPs) have the ability to penetrate as well as transport cargo across bacterial cell membranes, and they have been labeled as exceptional candidates to function in drug delivery. The aim of this study was to investigate the effectiveness of novel formulation of AMPs for enhanced MRSA activity. The strategy was carried out through the formulation of liposomes by thin-layer film hydration methodology, containing phosphatidylcholine, cholesterol, oleic acid, the novel AMP, as well as vancomycin (VCM). Characterization of the AMPs and liposomes included HPLC and LCMS for peptide purity and mass determination; DLS (size, polydispersity, zeta potential), TEM (surface morphology), dialysis (drug release), broth dilution, and flow cytometry (antibacterial activity); MTT assay, haemolysis and intracellular antibacterial studies. The size, PDI, and zeta potential of the drug-loaded AMP2-Lipo-1 were 102.6 ± 1.81 nm, 0.157 ± 0.01, and − 9.81 ± 1.69 mV, respectively, while for AMP3-Lipo-2 drug-loaded formulation, it was 146.4 ± 1.90 nm, 0.412 ± 0.05, and − 4.27 ± 1.25 mV respectively at pH 7.4. However, in acidic pH for both formulations, we observed an increase in size, PDI, and a switch to positive zeta potential, which indicated the pH responsiveness of our liposomal systems. The in vitro drug release studies demonstrated that liposomal formulations released VCM-HCl at a faster rate at pH 6.0 compared to pH 7.4. In vitro antibacterial activity against S. aureus and MRSA revealed that liposomes had enhanced activity at pH 6 compared to pH 7.4. The study revealed that the formulation can potentially be used to enhance activity and penetration of AMPs, thereby improving the treatment of bacterial infections.
TL;DR: Taurine improved learning and memory ability and significantly decreased apoptosis of the hippocampus neurons in T2D rats, and taurine supplement also inhibited high glucose-induced apoptosis in HT-22 cell in vitro.
Abstract: Type 2 Diabetes causes learning and memory deficits that might be mediated by hippocampus neuron apoptosis. Studies found that taurine might improve cognitive deficits under diabetic condition because of its ability to prevent hippocampus neuron apoptosis. However, the effect and mechanism is not clear. In this study, we explore the effect and mechanism of taurine on inhibiting hippocampus neuron apoptosis. Sixty male Sprague–Dawley rats were randomly divided into control, T2D, taurine treatment (giving 0.5%, 1%, and 2% taurine in drinking water) groups. Streptozotocin was used to establish the diabetes model. HT-22 cell (hippocampus neurons line) was used for in vitro experiments. Morris Water Maze test was used to check the learning and memory ability, TUNEL assay was used to measure apoptosis and nerve growth factor (NGF); Akt/Bad pathway relevant protein was detected by western blot. Taurine improved learning and memory ability and significantly decreased apoptosis of the hippocampus neurons in T2D rats. Moreover, taurine supplement also inhibited high glucose-induced apoptosis in HT-22 cell in vitro. Mechanistically, taurine increased the expression of NGF, phosphorylation of Trka, Akt, and Bad, as well as reduced cytochrome c release from mitochondria to cytosol. However, beneficial effects of taurine were blocked in the presence of anti-NGF antibody or Akt inhibitor. Taurine could inhibit hippocampus neuron apoptosis via NGF-Akt/Bad pathway. These results provide some clues that taurine might be efficient and feasible candidate for improvement of learning and memory ability in T2D rats.
TL;DR: Using molecular dynamics simulations, it was shown that the increased thermoresistance of MTG is caused by a higher backbone rigidity as well as increased hydrophobic interactions and newly formed hydrogen bridges.
Abstract: Microbial transglutaminase (MTG, EC 2.3.2.13) of Streptomyces mobaraensis is widely used in industry for its ability to synthesize isopeptide bonds between the proteinogenic side chains of glutamine and lysine. The activated wild-type enzyme irreversibly denatures at 60 °C with a pseudo-first-order kinetics and a half-life time (t1/2) of 2 min. To increase the thermoresistance of MTG for higher temperature applications, we generated 31 variants based on previous results obtained by random mutagenesis, DNA shuffling and saturation mutagenesis. The best variant TG16 with a specific combination of five of seven substitutions (S2P, S23Y, S24 N, H289Y, K294L) shows a 19-fold increased half-life at 60 °C (t1/2 = 38 min). As measured by differential scanning fluorimetry, the transition point of thermal unfolding was increased by 7.9 °C. Also for the thermoresistant variants, it was shown that inactivation process follows a pseudo-first-order reaction which is accompanied by irreversible aggregation and intramolecular self-crosslinking of the enzyme. Although the mutations are mostly located on the surface of the enzyme, kinetic constants determined with the standard substrate CBZ-Gln-Gly-OH revealed a decrease in KM from 8.6 mM (± 0.1) to 3.5 mM (± 0.1) for the recombinant wild-type MTG and TG16, respectively. The improved performance of TG16 at higher temperatures is exemplary demonstrated with the crosslinking of the substrate protein β-casein at 60 °C. Using molecular dynamics simulations, it was shown that the increased thermoresistance is caused by a higher backbone rigidity as well as increased hydrophobic interactions and newly formed hydrogen bridges.
TL;DR: The latest improvements in chromatographic direct methodologies based on chiral selectors are revised and aimed to improve analytical speed, sensitivity, robustness, and reproducibility of d-amino acid analysis in foodstuffs and pharmaceuticals.
Abstract: α-Amino acids are present in two opposite configurations due to the presence of a central carbon atom which is a chiral center. While L-amino acids are present in large amount in nature, only tiny quantities of their D-enantiomers exist. For a long time, D-amino acids have been considered of bacterial origin only, but recently we realized that they are present in all living organisms: notably, D-amino acids play specific and relevant functions in the different organisms. Detection and quantification of D-amino acids are mandatory to shed light on their physiological roles, especially related to foods and human health. Chromatographic techniques are among the most commonly used analytical methods for the enantioseparation of amino acids. Here, we revised the latest improvements in chromatographic direct methodologies based on chiral selectors and aimed to improve analytical speed, sensitivity, robustness, and reproducibility. While current methods are well suited for D-amino acid analysis in foodstuffs and pharmaceuticals, further improvements seem required for their simultaneous, fast and sensitive detection in biological fluids, an emerging field since D-amino acids have been proposed as biomarkers of different and relevant human pathologic states.
TL;DR: Findings indicate that reduced quantities of glycine observed in obese subjects likely results from an upregulation of the hepatic glycine cleavage system and that dietary glycine supplementation potentially reduces obesity in ZDF rats.
Abstract: Obesity is associated with altered glycine metabolism in humans. This study investigated the mechanisms regulating glycine metabolism in obese rats. Eight-week-old Zucker diabetic fatty rats (ZDF; a type-II diabetic animal model) received either 1% glycine or 1.19% l-alanine (isonitrogenous control) in drinking water for 6 weeks. An additional group of lean Zucker rats also received 1.19% l-alanine as a lean control. Glycine concentrations in serum and liver were markedly lower in obese versus lean rats. Enteral glycine supplementation restored both serum and hepatic glycine levels, while reducing mesenteric and internal white fat mass compared with alanine-treated ZDF rats. Blood glucose and non-esterified fatty acid (NEFA) concentrations did not differ between the control and glycine-supplemented ZDF rats (P > 0.10). Both mRNA and protein expression of aminomethyltransferase (AMT) and glycine dehydrogenase, decarboxylating (GLDC) were increased in the livers of obese versus lean rats (P < 0.05). In contrast, glycine cleavage system H (GCSH) hepatic mRNA expression was downregulated in obese versus lean rats, although there was no change in protein expression. These findings indicate that reduced quantities of glycine observed in obese subjects likely results from an upregulation of the hepatic glycine cleavage system and that dietary glycine supplementation potentially reduces obesity in ZDF rats.
TL;DR: The peptide analogue 5 showed 100% protection in the 6-Hz test, while the other seven VV-hemorphin-7 analogues have dose-dependent activity against psychomotor seizures comparable to 1 and did not show neurotoxicity in the rotarod test.
Abstract: Herein, some new analogues of VV-hemorphin-7, modified at position 4 and 7 by the unnatural amino acids followed the structure Val-Val-Tyr-Xxx-Trp-Thr-Yyy-Arg-Phe-NH2, where Xxx is Ac5c (1-aminocyclopentanecarboxylic acid) or Ac6c (1-aminocyclohexane carboxylic acid) and Yyy is Dap (diaminopropanoic acid) or Dab (diaminobutanoic acid), were synthesized, characterized and investigated for anticonvulsant activity. The new synthetic peptide analogues were prepared by standard solid-phase peptide synthesis—Fmoc chemistry. A single intracerebroventricular (i.c.v.) injection at doses of 5, 10, and 20 µg/10 µl, respectively, was given before evaluation with timed intravenous pentylenetetrazole (ivPTZ) infusion test and 6-Hz psychomotor seizure test in mice. The acute neurological toxicity was determined using the rotarod test. To explain the structure-active properties of the modified peptides, some physicochemical characteristic was obtained. The FT-IR spectra and their second derivatives of the amide I, II, and III bands of the peptides show s-sheet structure conformation. The calculation of isoelectric points, by potentiometric determination of dissociated constants, is in the range from 9.79 to 10.84. This study, for the first time, also reported on the reduction-oxidative potentials of the guanidine at Arg-moiety on such kind of peptides containing arginine and tyrosine residues in different medium and electrode surface. The VV-hemorphin-7 analogues 4 and 5 were the most active against the ivPTZ test, with the effect comparable to that of peptide 1 used as a positive control. Except compound 8, all other tested peptide analogues were ineffective to raise the threshold for the clonic seizures. The peptide analogue 5 showed 100% protection in the 6-Hz test, while the other seven VV-hemorphin-7 analogues have dose-dependent activity against psychomotor seizures comparable to 1. The novel peptides did not show neurotoxicity in the rotarod test.
TL;DR: Development of acrolein scavenger medicines containing SH-group such as N -acetylcysteine derivatives is important to maintain QOL (quality of life) of the elderly.
Abstract: It was found recently that acrolein (CH2=CH-CHO), mainly produced from spermine, is more toxic than ROS (reactive oxygen species, O2-·, H2O2, and ·OH). In this review, we describe how the seriousness of brain infarction, dementia, renal failure, and Sjӧgren's syndrome is correlated with acrolein. In brain infarction and dementia, it was possible to identify incipient patients with high sensitivity and specificity by measuring protein-conjugated acrolein (PC-Acro) in plasma together with IL-6 and CRP in brain infarction and Aβ40/42 in dementia. The level of PC-Acro in plasma and saliva correlated with the seriousness of renal failure and Sjӧgren's syndrome, respectively. Thus, development of acrolein scavenger medicines containing SH-group such as N-acetylcysteine derivatives is important to maintain QOL (quality of life) of the elderly.
TL;DR: The present findings suggest that the treatment with agmatine is able to counteract the neuronal cell injury evoked by mitochondrial toxins, as indicated by experiments using a HIF-1α inhibitor.
Abstract: Agmatine, a metabolite generated by arginine decarboxylation, has been reported as neuromodulator and neuroactive substance. Several findings suggest that agmatine displays neuroprotective effects in several models of neurodegenerative disorders, such as Parkinson's disease (PD). It has been hypothesized that biogenic amines may be involved in neuroprotection by scavenging oxygen radicals, thus preventing the generation of oxidative stress. Mitochondrial dysfunction, that leads to a reduction of oxygen consumption, followed by activation of prolyl hydroxylase and decrease of hypoxia-inducible factor 1 alpha (HIF-1α) levels, has been demonstrated to play a role in PD pathogenesis. Using rotenone-treated differentiated SH-SY5Y cells as the in vitro PD model, we here investigated the molecular mechanisms underlying agmatine neuroprotective effects. Our results showed that the preliminary addition of agmatine induces HIF-1α activation, and prevents the rotenone-induced production of free radical species, and the activation of apoptotic pathways by inhibiting mitochondrial membrane potential decrease and caspase 3 as well as cytochrome c increase. Notably, these effects are mediated by HIF-1α, as indicated by experiments using a HIF-1α inhibitor. The present findings suggest that the treatment with agmatine is able to counteract the neuronal cell injury evoked by mitochondrial toxins.
TL;DR: The role of spermine oxidase, as a hydrogen peroxide producer, in the oxidative stress during epilepsy is pointed out, which strongly indicates this transgenic mouse line as a potential animal model to study epilepsy.
Abstract: Several studies have demonstrated high polyamine levels in brain diseases such as epilepsy. Epilepsy is the fourth most common neurological disorder and affects people of all ages. Excitotoxic stress has been associated with epilepsy and it is considered one of the main causes of neuronal degeneration and death. The transgenic mouse line Dach-SMOX, with CD1 background, specifically overexpressing spermine oxidase in brain cortex, has been proven to be highly susceptible to epileptic seizures and excitotoxic stress induced by kainic acid. In this study, we analysed the effect of spermine oxidase over-expression in a different epileptic model, pentylenetetrazole. Behavioural evaluations of transgenic mice compared to controls showed a higher susceptibility towards pentylentetrazole. High-performance liquid chromatography analysis of transgenic brain from treated mice revealed altered polyamine content. Immunoistochemical analysis indicated a rise of 8-oxo-7,8-dihydro-2′-deoxyguanosine, demonstrating an increase in oxidative damage, and an augmentation of system xc− as a defence mechanism. This cascade of events can be initially linked to an increase in protein kinase C alpha, as shown by Western blot. This research points out the role of spermine oxidase, as a hydrogen peroxide producer, in the oxidative stress during epilepsy. Moreover, Dach-SMOX susceptibility demonstrated by two different epileptic models strongly indicates this transgenic mouse line as a potential animal model to study epilepsy.
TL;DR: Specific immunolocalization of D-alanine in pituitary ACTH-secreting cells and pancreatic β-cells suggests that this amino acid participates in blood glucose regulation in mammals, and D-serine probably participates in the control of systemic glucose metabolism by modulating insulin secretion.
Abstract: D-Aspartate, D-serine and D-alanine are a regular occurrence in mammalian endocrine tissues, though in amounts varying with the type of gland. The pituitary gland, pineal gland, thyroid, adrenal glands and testis contain relatively large amounts of D-aspartate in all species examined. D-alanine is relatively abundant in the pituitary gland and pancreas. High levels of D-serine characterize the hypothalamus. D-leucine, D-proline and D-glutamate are generally low. The current knowledge of physiological roles of D-amino acids in endocrine tissues is far from exhaustive, yet the topic is attracting increasing interest because of its potential in pharmacological application. D-aspartate is known to act at all levels of the hypothalamus-pituitary-testis axis, playing a key role in reproductive biology in several vertebrate classes. An involvement of D-amino acids in the endocrine function of the pancreas is emerging. D-Aspartate has been immunolocalized in insulin-containing secretory granules in INS-1 E clonal β cells and is co-secreted with insulin by exocytosis. Specific immunolocalization of D-alanine in pituitary ACTH-secreting cells and pancreatic β-cells suggests that this amino acid participates in blood glucose regulation in mammals. By modulating insulin secretion, D-serine probably participates in the control of systemic glucose metabolism by modulating insulin secretion. We anticipate that future investigation will significantly increase the functional repertoire of D-amino acids in homeostatic control.
TL;DR: This study investigated the Fmoc removal step, using the tea-bag strategy, and found 4-methyl piperidine to be an excellent alternative to the usually used p Piperidine in terms of purity and compliance with green chemistry principles.
Abstract: Several factors have influenced the increasing presence of peptides as an important class of Active Pharmaceutical Ingredients. One is the continued development of synthetic methodologies for peptide synthesis. Herein, we investigated the Fmoc removal step, using the tea-bag strategy. In this regard, three different secondary amines: piperidine, 4-methylpiperidine, and piperazine, were evaluated. As a result of this study, 4-methyl piperidine showed to be an excellent alternative to the usually used piperidine in terms of purity and compliance with green chemistry principles as well.
TL;DR: Early intensive nutrition intervention with oral supplements of Texidrofolico ® during chemotherapy of NSCLC patients prevents weight loss and it is beneficial for their quality of life.
Abstract: Weight loss in patients with cancer is caused by cancer cachexia and chemotherapy-induced nausea and vomiting. Recent developments in antiemetic drugs have substantially improved nausea and vomiting, but this intervention did not reduce weight loss and other more severe side effects of chemotherapy, like anorexia, weakness, cough, dyspnea, hemoptysis, and pain. This study aimed to investigate the effects of nutrition intervention with a food supplement, during chemotherapy in patients with advanced nonsquamous non-small cell lung cancer (NSCLC). Patients received individualized nutrition counseling by a registered dietitian and were provided with oral supplements of Texidrofolico® for 90 days. Bodyweight and the mentioned other side effects were evaluated at baseline and after 90 days of intervention. To assess the effects of this dietary supplement, a total of 30 patients were retrospectively enrolled as controls, and the bodyweight and change in side effects of chemotherapy were compared with those observed in 30 Texidrofolico®-treated patients. After 90-day intervention, by oral supplement of Texidrofolico®, the patients, during the course of cytotoxic chemotherapy, showed an improved quality of life and not significant weight and BMI loss respect the control group. Furthermore, the number of patients, treated with Texidrofolico® who maintained or increased their body weight, after 90 days of treatment was significantly higher than in the control group. The effects of treatment with the food supplement have also been studied from a metabolic point of view. It was possible to find that one of the known markers of tumor growth, plasma polyamines, was reduced after the treatment. A possible relationship between these biogenic amines and the folate cycle is discussed. In conclusion, early intensive nutrition intervention with oral supplements of Texidrofolico® during chemotherapy of NSCLC patients prevents weight loss and it is beneficial for their quality of life.