Low Molecular Weight Amino Acids Research Articles

Metabolic and biochemical analyses reveal heavy metals tolerance mechanisms in Amaranthus retroflexus L.

One of the most prevalent plant species in the contaminated area around a sewage dumping lake at Khulais (Jeddah, Saudi Arabia) in the Arabian desert eco-region was found to be Amaranthus retroflexus L. This plant has the capacity to bioaccumulate and bioremediate heavy metals. The current study, therefore, aimed at investigating the plant's defense mechanisms by conducting metabolic and biochemical assessments. To this end, A. retroflexus plants were collected from the sewage dumping lake of Khulais, across five sites at varying distances from the lake, each exhibiting different level of heavy metal. The results indicated an increase in antioxidant defense system emerged as a protection strategy for A. retroflexus plants against soil contaminations. This, for instance, included the increased synthesis of polyamines (e.g., putrescine, spermidine, and spermine by +9–63%), flavonoids (e.g., naringenin, kaempferol, luteolin, and rutin by +10–146%), and phenolic acids (e.g., chlorogenic acid, gallic acid, caffeic acid, p-coumaric acid, chicoric acid, rosmarinic acid, and protocatechuic acid), increased by 10–254%. Additionally, plants adjusted their metabolic processes by synthesizing various low molecular weight amino acids, including proline (+19–299%), phenylalanine (+98–240%), glutamate (+34–492%), arginine (+10–64%), and ornithine (+51–210%). The activity of the metabolic enzymes involved in metabolism of these amino acids was enhanced accordingly. It can be concluded that the synthesis of polyamines and amino acids can be coordinated and complemented to improve the tolerance of A. retroflexus to cope with heavy metal accumulation in contaminated soils.

Rational design of an innovative hybrid biosensor utilizing functionalized ZnO-Cys-graphene ternary composite for enzyme-free glucose detection

The limitations of enzymatic sensors for glucose detection have been addressed through the development of non-enzymatic sensors utilizing Zinc Oxide (ZnO). ZnO is an attractive choice due to its favourable properties, including cost-effectiveness, catalytic activity, large surface area, high adsorption capacity, and biocompatibility, which make it well-suited for glucose sensing applications. To enhance sensing performance, L-Cysteine, a low molecular weight amino acid, was employed as a capping agent for ZnO, leveraging its functional groups to improve the sensor's adsorption capacity and sensitivity. Additionally, graphene, a two-dimensional carbon material with excellent conductivity and surface area, was incorporated into the composite of cysteine-capped ZnO (ZnO-Cys), resulting in a ZnO-Cysteine-Graphene (ZnO-Cys-GNS) composite. This incorporation aimed to further enhance the sensing properties of the biosensor. The final products ZnO, ZnO-Cys, ZnO-Cys-GNS were characterized by XRD, SEM, TEM, FTIR and Raman spectroscopy to analyse its structure and morphology. CV and chronoamperometry were used for electrochemical measurements to evaluate the glucose detection capabilities of the materials. The results demonstrated ZnO-Cys-GNS composite showed higher activity towards glucose detection and exhibits sensitivity of 161.12 μA/(mM.cm2) and lower detection limit of 0.663 μM with wide linear detection range from 0.01 mM to 1 mM. The utilization of non-enzymatic sensors based on metal oxides, such as ZnO, and the incorporation of functional molecules like L-Cysteine and graphene overcome the limitations associated with enzymatic sensors, offering a more stable and efficient approach for glucose detection.

Efficient Fe(III)/Fe(II) cycling mediated by L-cysteine functionalized zero-valent iron for enhancing Cr(VI) removal

Herein, L-cysteine (Cys) was modified on zero-valent iron (C-ZVIbm) by using a mechanical ball-milling method to improve the surface functionality and the Cr(VI) removal efficiency. Characterization results indicated that Cys was modified on the surface of ZVI by the specific adsorption of Cys on the oxide shell to form a -COO-Fe complex. The Cr(VI) removal efficiency of C-ZVIbm (99.6%) was much higher than that of ZVIbm (7.3%) in 30 min. The attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) analysis inferred that Cr(VI) was more likely to be adsorbed on the surface of C-ZVIbm to form bidentate binuclear inner-sphere complexes. The adsorption process was well-matched to the Freundlich isotherm and the pseudo-second-order kinetic model. Electrochemical analysis and electron paramagnetic resonance (ESR) spectroscopy revealed that Cys on the C-ZVIbm lowered the redox potential of Fe(III)/Fe(II), and favored the surface Fe(III)/Fe(II) cycling mediated by the electrons from Fe0 core. These electron transfer processes were beneficial to the surface reduction of Cr(VI) to Cr(III). Our findings provide new understandings into the surface modification of ZVI with a low-molecular weight amino acid to promote in-situ Fe(III)/Fe(II) cycling, and have great potential for the construction of efficient systems for Cr(VI) removal.

Production of small peptides and low molecular weight amino acids by subcritical water from fish meal: Effect of pressurization agent

The hydrolysis of the water-soluble protein (WSP) fraction from tuna fish meal was evaluated by subcritical water (subW) by using N2 and CO2 as different pressurization agents in the temperature range from 140 to 180 °C. For both gases, the amino group release increased by increasing working temperature while the Lowry response decreased due to production of smaller-size peptides and free amino acids.The free amino acid content was higher with CO2 than with N2. At 180 °C, 344 ± 5 and 275 ± 3 mg of free amino acids per g of WSP were released, respectively; although, in both systems the smallest molecular weight amino acids, glycine and alanine, were preferentially released. The free amino acids content obtained by enzymatic hydrolysis with commercial proteases Alcalase and Novozym was much lower with the highest hydrolysis yield determined for histidine. These results have been supported by size exclusion chromatography analysis.

Effect of Adding L-carnitine to High-Fat/Low-Protein Diets of Common Carp (Cyprinus carpio) and the Mechanism of Regulation of Fat and Protein Metabolism.

L-carnitine is a low molecular weight amino acid that plays an essential role in the oxidation of long-chain fatty acids. The regulatory effects and molecular mechanisms of L-carnitine on fat and protein metabolism in common carp (Cyprinus carpio) were investigated in this study. Common carp (n = 270) were randomly divided into three groups and fed either (1) common carp diet, (2) high-fat/low-protein diet, or (3) L-carnitine-high-fat/low-protein diet. Growth performance, plasma biochemistry, muscle composition, and ammonia excretion rate were all examined after 8 weeks. Additionally, each group's hepatopancreas was subjected to transcriptome analysis. The results showed that decreasing the feed protein/fat ratio resulted in a considerable increase in feed conversion ratio and a significant decrease in common carp-specific growth rate to 1.19 ± 0.02 (P < 0.05). Similarly, total plasma cholesterol sharply increased to 10.15 ± 2.07, while plasma urea nitrogen, muscle protein, and ammonia excretion levels dropped (P < 0.05). After adding L-carnitine to the high-fat/low-protein diet, it was found that the specific growth rate and protein content of the dorsal muscle increased significantly (P < 0.05). In contrast, the plasma total cholesterol and ammonia excretion rate decreased considerably at most time points after feeding (P < 0.05). The expression of genes in the hepatopancreas differed substantially between the different groups. Through GO analysis, it was demonstrated that L-carnitine increased the ability of fat decomposition by up-regulating the expression of cpt1 in the hepatopancreas and decreased the expression of fasn and elovl6 to reduce the production and extension of lipids. Simultaneously, mtor was more abundant in the hepatopancreas, implying that L-carnitine can increase protein synthesis. According to the findings, adding L-carnitine to high-fat/low-protein diets can stimulate growth by enhancing lipolysis and protein synthesis.

A supramolecular glass made from a low molecular weight amino acid derivative

A low molecular weight tyrosine derivative with self-assembling capabilities has been found to form a robust optically transparent supramolecular glass after casting at 70 °C. The glass films are remarkably stable, remaining transparent over 12 + months as well as in contact with water and can be reprocessed via solvation in a wide range of organic solvents. The solubility, long-term stability and thermo-responsive properties of the bio-derived glass makes it an ideal candidate for use as a window where its reprocessability at easily accessible temperatures are attractive.

Secondary carbonates in edaphic components of ecosystems

The paper considers some examples of secondary carbonates in edaphic ecosystem components (soils, river and lake bottom sediments, suspensions). In addition to calcite, more soluble and less stable polymorphic modifications of calcite vaterite and aragonite, which are important precursors of carbonate-forming systems, are diagnosed. Microforms of vaterite are formed in presence of low molecular weight amino acids. In turn, microforms of aragonite are associated with extremely high salinity of water. According to the nonclassical mesocrystal concept, stability of vaterite and aragonite in situ is explained by the formation of mesocrystals – hierarchically organized superstructures from nanocrystals. The mesocrystal concept may be an important key to understanding the micro-and macroaggregates in soils.

Bifidobacterium animalis subspecies lactis engineered to produce mycosporin-like amino acids in colorectal cancer prevention.

Colorectal cancer is the third most common cancer and the third leading cause of cancer-related death. The pathogensesis of colorectal cancer involves a multi-step and multi-factorial process. Disruption of the gut microbiota has been associated with gastrointestinal diseases such as colorectal cancer. The genus Bifidobacterium is considered an important component of the commensal microbiota and plays important roles in several homeostatic functions: immune, neurohormonal, and metabolic. Bifidobacterium animalis subsp. lactis is a well-documented probiotic within the species Bifidobacterium. Mycosporin-like amino acids are low molecular weight amino acids demonstrated to exert prebiotic effects and to modulate host immunity by regulating the proliferation and differentiation of intestinal epithelial cells, macrophages and lymphocytes, as well as cytokine production.Their modulation of the metabolism of the immune system and transcription factors could exert a beneficial effect on colorectal cancer. B. animalis does not produce mycosporin-like amino acids. If one could create a B. animalis–producing mycosporin-like amino acids via genetic open reading frame engineering it should exert more potent immuno-stimulatory properties and, thereby, become a potent strain-specific microbial based therapy in colorectal cancer prevention.

A porous layer open-tubular capillary column with immobilized pH gradient (PLOT-IPG) for isoelectric focusing of amino acids and proteins

A porous layer open-tubular capillary column with immobilized pH gradient (PLOT-IPG) was prepared in two steps. First, a partially filled porous layer open tubular capillary column containing active epoxy groups was synthesized by in situ polymerization of acrylamide, glycidyl methacrylate, and N,N′-methylenebisacrylamide. Then, an aqueous solution of commercial carrier ampholytes (CAs, Pharmalyte) was focused in the prepared polymer column. With the column immobilized by Pharmalyte 4.5–6.0 (narrow pH range) or Pharmalyte 3.0–10.0 (wide pH range), proteins with known pIs were separated and a good linear correlation between pI values and migration times was obtained. Meanwhile, resolution was improved compared to the traditional gradient with a wide pH range. A mixture of low molecular weight amino acids was separated with the narrow pH range PLOT-IPG column; from the obtained results, the resolution of our new column was calculated to be at most 0.09 pH unit. In addition, human serum proteins were analyzed with the newly developed wide and narrow pH range PLOT-IPG columns; its sensitivity and resolution in the narrow pH range one were better than capillary electrophoresis.

Insights into the formation mechanism of vaterite mediated by a deep-sea bacterium Shewanella piezotolerans WP3

Abstract Microbially mediated carbonate mineralization plays a crucial role in biogeochemical cycling of carbon, as microbes can efficiently transform atmospheric CO2 and organic carbon into carbonate cements which represent a significant sink in the global carbon cycle. It is well established that diverse bacteria from various natural habitats can induce the precipitation of calcium carbonate, and an increasing number of bacteria were found to be able to mediate the mineralization of vaterite. However, the precise mechanisms for the formation of bacterial vaterite are not fully understood. To better understand the effect of bacterial activity on vaterite formation, Shewanella piezotolerans WP3 was selected as a model microbe to induce calcium carbonate mineralization. A combination of bacterial and biomimetic mineralization experiments was adopted. Different bacterial components including native cells, EPS-free cells, cell-bound EPS, soluble EPS, and small molecule organics were isolated from the cultures and used to influence calcium carbonate crystallization and growth. The identification and characterization of the mineralized products were done using field emission scanning electron microscopy (FESEM), X-ray powder diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), thermogravimetry and differential thermal analysis (TG-DTA), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and selected area electron diffraction (SAED). Bacterial in situ mineralization experiments demonstrate that S. piezotolerans WP3 can not only promote the mineralization of calcium carbonate, but also mediate polymorph selection of vaterite. Biomimetic mineralization experiments involving individual bacterial components reveal that different bacterial components have different effects on calcium carbonate polymorphism, and low molecular-weight amino acids secreted by the bacteria play a dominant role on vaterite formation and stabilization. Our observations also suggest that soluble EPS can induce the formation of aragonite while bound EPS facilitate calcite erosion. Current results can provide a deeper insight into bacterially mediated mineralization of vaterite and calcium carbonate polymorphism problem, and help evaluate the significance of biogenic carbonate in the diagenetic carbonate sinks.

Comparison of the Self-Assembly Behavior of Fmoc-Phenylalanine and Corresponding Peptoid Derivatives

Fluorenylmethoxycarbonyl-protected phenylalanine (Fmoc-Phe) derivatives are a privileged class of low molecular weight amino acid hydrogelators that undergo spontaneous self-assembly in water to form one-dimensional (1D) fibril networks. Structural studies indicate that these fibrils feature unidirectional hydrogen bonding and parallel π–π interactions (Fmoc–Fmoc and side chain benzyl–benzyl), which stabilize the 1D fibrils. However, the relative contribution of hydrogen bonding vs π–π interactions in these assemblies is not understood. Herein, we compare the self-assembly of Fmoc-Phe amino acids with corresponding Fmoc-protected peptoid derivatives. The N-benzyl glycine-derived peptoid analogues exhibit altered hydrogen bonding ability and benzyl side chain presentation geometry relative to the parent Fmoc-Phe molecules. We found that Fmoc-peptoid analogues preferentially assemble into two-dimensional (2D) nano- and microsheets that ultimately adopt crystalline states, whereas the Fmoc-Phe amino acids as...

Характеристика імунотропних функціональних інгредієнтів бактеріального походження, отриманих шляхом фізичного впливу

Зазначено, що складові пептидогліканів клітинних стінок бактерій, у тому числі молочнокислих, володіють високою функціонально-фізіологічною активністю і є вельми перспективними харчовими імунотропними інгредієнтами. Доцільною є деструкція бактеріальних клітин з метою отримання біологічно активних сполук, здатних легше засвоюватися і вступати в біохімічні процеси, прискорюючи очікуваний імунотропний ефект. У роботі вивчено вплив фізичних дезінтегруючи факторів, а саме, ультразвуку та мікрохвиль НВЧ, на ефективність деструкції клітинних стінок Lactobacillus acidophilus. Надано порівняльну характеристику дезінтегратів бактеріальної маси (БМ) Lactobacillus acidophilus, отриманих із застосуванням ультразвуку та мікрохвиль НВЧ. Показано, що більш ефективним методом фізичної деструкції бактеріальних клітин є обробка ультразвуком. Встановлено молекулярно-масовий розподіл сполук білкової природи та вміст незамінних амінокислот у складі дезінтеграту, отриманого шляхом обробки БМ ультразвуком.

Differential Utilization of Dissolved Organic and Inorganic Nitrogen by Wheat (Triticum Aestivum L.)

A study was conducted under greenhouse conditions on wheat to investigate the utilization of dissolved organic nitrogen (N) in comparison with conventionally applied inorganic N sources (INS). Nitrogen was applied at a rate of 90 kg N ha−1 in an inorganic form, an organic high molecular weight (MW) form (casein, haemoglobin, albumin), and an organic low MW amino acid form (glycine, alanine, valine). Inorganic N sources recorded the maximum response (126% to 150%) in total dry matter (DM) production while dissolved organic nitrogen (DON) sources showed 61% to 116% increase in comparison to the control treatment. Glycine gave the maximum DM production, which was comparable with both INS treatments. In hydroponics, greater utilization occurred and the shoots had a higher N content in comparison to those grown in soil. The concentration of DON and NO3− in soil after wheat harvest was similar in all the treatments.

Preventive effect of low molecular weight dextranon and amino acid injection against venous thromboembolism after radical correction of cavitas pelvis

Preventive effect of low molecular weight dextranon and amino acid injection against venous thromboembolism after radical correction of cavitas pelvis

Bio-functionalisation to enzymatically control the solution properties of a self-supporting polymeric material

Molecular self-assembly permits the spontaneous aggregation of a variety of low molecular weight amino acid subunits into highly ordered aggregates. Functionalisation of water soluble poly(allylamine) with acetyl protected dialanine enables the formation of a biopolymer self-supporting material (SSM). The presence of an enzyme cleavable dipeptide linker renders the SSM responsive to disruption by a targeted proteolytic enzyme.

Sub-critical water hydrolysis of hog hair for amino acid production

A recycling method using sub-critical water hydrolysis to convert hog hair from slaughterhouses into amino acids was developed. The influence of the reaction parameters such as temperature, time of reaction and initial substrate concentration were investigated in a batch reactor. The quality and quantity of amino acids in hydrolysates were determined and 17 kinds of amino acids were obtained. Under the tested conditions, the highest amino acid yield (325 mg/g protein) was reached at an initial substrate concentration of 10 g/l, a temperature of 250 °C and a reaction time of 60 min. A large amount of low-molecular weight amino acids, such alanine and glycine, was observed at these operating conditions. Sub-critical water hydrolysis was confirmed as an effective and practical process to recover amino acids from hog hair waste.

Seasonal development of phloem in Siberian larch stems

The seasonal development of phloem in the stems of Siberian larch (Larix sibirica Ldb.) was studied over two seasons on 50-60-year-old trees growing in a natural stand in the Siberian forest-steppe zone. Trees at the age of 20-25 years were used to study metabolites in differentiating and mature phloem elements, cambial zone, and radially growing xylem cells in the period of early and late wood formation. The development of the current-year phloem in the stems of 50-60-year-old trees started, depending on climatic conditions, in the second-third decades of May, 10-20 days before the xylem formation, and ended together with the shoot growth cessation in late July. Monitoring of the seasonal activity of cambium producing phloem sieve cells and the duration of their differentiation compared to the xylem derivatives in the cambium demonstrated that the top production of phloem and xylem cells could coincide or not coincide during the season, while their differentiation activity was always in antiphase. Sieve cells in the early phloem are separated from those in the late phloem by a layer of tannin-containing cells, which are formed in the period when late xylem formation starts. The starch content in the structural elements of phloem depends on the state of annual xylem layer development. The content of low molecular weight carbohydrates, amino acids, organic acids, and phenols in phloem cells, cambial zone, and xylem derivatives of the cambium depends on the cell type and developmental stage as well as on the type of forming wood (early or late) differing by the cell wall parameters and, hence, by the requirement for assimilates. Significant differences in the dynamics of substances per dry weight and cell were observed during cell development.

Decarboxylation Mechanism of Amino Acids by Density Functional Theory

The decarboxylation mechanisms of amino acids with and without water were studied by density functional theory at the B3LYP/6-31G level. Without water, two decarboxylation channels exist for the low molecular weight amino acids glycine (Gly) and alanine (Ala), whereas only one exists for the other amino acids. Channel one for Gly and Ala takes place from a neutral conformer in which the carboxylic hydrogen is intramolecularly hydrogen bonded to the nitrogen atom of the amino group. During the development of the transition-state structure, the carboxylic hydrogen atom first shifts to the amino group forming the zwitterion and then from the −NH3+ group to the α-carbon forming the product amine. Accompanying proton transfer, the C−CO2 bond elongates. Channel two starts from the higher-energy anti carboxylic hydrogen conformer and involves the direct heterolytic loss of CO2 accompanied by simultaneous proton transfer. The calculated energy barriers range from 288 to 307 kJ/mol with an average of 299 kJ/mol. T...

Assimilation and partitioning of prey nitrogen within two anthozoans and their endosymbiotic zooxanthellae

The movement of nitrogen from zooplankton prey into the temperate scleractinian coral Oculina arbuscula and the anemone Aiptasia pallida was measured using 15 N-labeled brine shrimp. The efficiency with which prey nitrogen was incorporated into cnidarian tissues was species-specific. O. arbuscula with a full complement of zooxanthellae had an assimilation efficiency of nearly 100%, compared to only 46% for corals containing few zooxanthellae. In A. pallida, symbiont density had no effect, and nitrogen assimilation was 23 to 29%. In both species, the host retained the bulk of the ingested label. Complete digestion was rapid (<4 h), as was the partitioning of the label between host amino acids and macromolecules. The label was primarily in the low-molecular weight-amino acid pool in O. arbuscula, where it remained for 30 h. A maximum of ca. 20% of the 15 N appeared in the zooxanthellae, where it was rapidly converted into macromolecules. Individual amino acids in A. pal- lida tissues were highly labeled with 15 N within 4 h and showed no subsequent enrichment with time; however, zooxanthellae amino acids became increasingly enriched over 30 h. Differences in 15 N enrichment among amino acids were consistent with known synthesis and transformation pathways, but it was not possible to discriminate between host feeding and de novo synthesis.

Facilitation of pulmonary insulin absorption by H-MAP: pharmacokinetics and pharmacodynamics in rats.

Several low molecular weight amino acids have previously been reported to enable the oral delivery of proteins. In the present studies, the effect of H-MAP (hydroxy methyl amino propionic acid) on the pharmacokinetics (PK) and pharmacodynamics (PD) of porcine insulin delivered to the lungs of rats by spray-instillation (SI) has been determined. Aliquots (100 microl) of increasing doses of porcine insulin alone (0.26, 1.3, 2.6, 13, and 26 U/kg) or combined with increasing doses of H-MAP (5, 10, 16, and 25 mg/kg), at pH 7.2-7.6 were administered intratracheally to fasted anesthetized rats using a micro spray-instillator. Blood samples were collected from the jugular vein at specified intervals and the plasma concentrations of insulin and glucose were determined. The PK and PD of porcine insulin alone following subcutaneous (SC) administration of increasing doses were also determined. The PK of insulin administered either by SI to the lungs or SC injection were absorption rate dependent, resulting in post-peak half-lives 10 to 25-fold greater than the reported intravenous elimination half-life (3 min). The relative bioavailability (F') of insulin administered alone by SI varied from 23.8 to 80% for the lowest and highest insulin dose, respectively. Co-administration of H-MAP and insulin to the lungs significantly changed the PK and PD of insulin in a dose dependent fashion. Maximum PK and PD responses were obtained at an H-MAP dose of 16 mg/kg and an insulin dose of 1.3 U/kg. At this combination, the relative bioavailability of insulin was increased more than 2.5 fold, maximum concentration (Cmax) increased 2-fold and the minimum plasma glucose concentration (%MPGC) was reduced more than 2-fold with respect to same dose of insulin alone. A greater total reduction in plasma glucose (%TRPG0-->t) was achieved for H-MAP/insulin combination (66+/-5%) compared to insulin alone (47+/-10 %). H-MAP has potential for increasing the pulmonary bioavailability of insulin administered through the lungs.