Content Of Basic Amino Acids Research Articles

Antimicrobial peptides derived from food byproducts: Sources, production, purification, applications, and challenges.

Food wastes can be a valuable reservoir of bioactive substances that can serve as natural preservatives in foods or as functional ingredients with potential health benefits. The antimicrobial properties of protein hydrolysates, especially antimicrobial peptides (AMPs) derived from food byproducts (FBs), have been extensively explored. These protein fragments are defined by their short length, low molecular weight, substantial content of hydrophobic and basic amino acids, and positive net charge. The intricate mechanisms by which these peptides exert their antimicrobial effects on microorganisms and pathogens have been elaborately described. This review also focuses on techniques for producing and purifying AMPs from diverse FBs, including seafood, livestock, poultry, plants, and dairy wastes. According to investigations, incorporating AMPs as additives and alternatives to chemical preservatives in food formulations and packaging materials has been pursued to enhance both consumer health and the shelf life of foods and their products. However, challenges associated with the utilization of AMPs derived from food waste depend on their interaction with the food matrix, acceptability, and commercial viability. Overall, AMPs can serve as alternative safe additives, thereby ensuring the safety and prolonging the storage duration of food products based on specific regulatory approvals as recommended by the respective safety authorities.

The Influence of Micronization on the Properties of Black Cumin Pressing Waste Material.

The purpose of this study was to investigate the effect of micronization on the characteristics of black cumin pressing waste material. The basic composition, amino acid, and fatty acid content of the raw material-specifically, black cumin pressing waste material-were determined. The samples were micronized in a planetary ball mill for periods ranging from 0 to 20 min. The particle sizes of micronized samples of black cumin pressing waste material were then examined using a laser analyzer, the Mastersizer 3000. The structures of the produced micronized powders was examined by X-ray diffraction. Additionally, the FTIR (Fourier-transform infrared) spectra of the micronized samples were recorded. The measurement of phenolic and antiradical properties was conducted both before and after in vitro digestion, and the evaluation of protein digestibility and trypsin inhibition was also conducted. The test results, including material properties, suggest that micronization for 10 min dramatically reduced particle diameters (d50) from 374.7 to 88.7 µm, whereas after 20 min, d50 decreased to only 64.5 µm. The results obtained using FTIR spectroscopy revealed alterations, especially in terms of intensity and, to a lesser extent, the shapes of the bands, indicating a significant impact on the molecular properties of the tested samples. X-ray diffraction profiles revealed that the internal structures of all powders are amorphous, and micronization methods have no effect on the internal structures of powders derived from black cumin pressing waste. Biochemical analyses revealed the viability of utilizing micronized powders from black cumin pressing waste materials as beneficial food additives, since micronization increased total phenolic extraction and antiradical activity.

High pressure-assisted enzymatic hydrolysis promotes the release of a bi-functional peptide from cowhide gelatin with dipeptidyl peptidase IV (DPP-IV) inhibitory and antioxidant activities

The process of generating functional peptides from cowhide gelatin is challenged by inefficient enzymatic hydrolysis. In this study, the researchers attempted to enhance the hydrolysis and potential functional properties of the peptides by subjecting the cowhide gelatin to high-pressure treatment (200, 300, and 400 MPa) for 20 min, followed by enzymatic hydrolysis. The highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, 2,2′ azinobis(3 ethylbenzothiazoline 6 sulfonic acid) (ABTS) radical scavenging activity, and DPP-IV inhibitory activity of the hydrolysate were obtained at 200 MPa, accompanied with an increase in the content of hydrophobic, acidic, and basic amino acids (P < 0.05). Correspondingly, the high-pressure pretreatment (200 MPa) reduced the thermal stability, particle size, and morphological integrity of cowhide gelatin, with a corresponding increase in the exposure of hydrophobic regions. Altogether, these results indicated that appropriate high-pressure-assisted enzymatic hydrolysis reinforced the release of bi-functional peptides by modifying the structure of cowhide gelatin.

Integrated transcriptomics and metabolomics analysis reveals key regulatory network that response to cold stress in common Bean (Phaseolus vulgaris L.)

Cold temperatures can be detrimental to crop survival and productivity. Breeding progress can be improved by understanding the molecular basis of low temperature tolerance. We investigated the key routes and critical metabolites related to low temperature resistance in cold-tolerant and -sensitive common bean cultivars 120 and 093, respectively. Many potential genes and metabolites implicated in major metabolic pathways during the chilling stress response were identified through transcriptomics and metabolomics research. Under chilling stress, the expression of many genes involved in lipid, amino acid, and flavonoid metabolism, as well as metabolite accumulation increased in the two bean types. Malondialdehyde (MDA) content was lower in 120 than in 093. Regarding amino acid metabolism, 120 had a higher concentration of acidic amino acids than 093, whereas 093 had a higher concentration of basic amino acids. Methionine accumulation was clearly higher in 120 than in 093. In addition, 120 had a higher concentration of many types of flavonoids than 093. Flavonoids, methionine and malondialdehyde could be used as biomarkers of plant chilling injury. Transcriptome analysis of hormone metabolism revealed considerably greater, expression of abscisic acid (ABA), gibberellin (GA), and jasmonic acid (JA) in 093 than in 120 during chilling stress, indicating that hormone regulation modes in 093 and 120 were different. Thus, chilling stress tolerance is different between 093 and 120 possibly due to transcriptional and metabolic regulation.

Antimicrobial activities and mechanism of sturgeon spermary protein extracts against Escherichia coli.

This study aimed to evaluate the antimicrobial activities and mechanism of sturgeon spermary protein extracts (SSPE) against Escherichia coli. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined. Cell structural change was analyzed using scanning electron microscopy-energy dispersive X-ray spectrometry and transmission electron microscope. Moreover, pH, zeta potential, membrane potential, intracellular ATP concentrations and the interaction of SSPE with genomic DNA were analyzed. Results showed that molecular weight of SSPE is 13.4 kDa, the content of basic amino acids is the highest, in which arginine accounts for 73.2%. The MIC and MBC of SSPE for E. coli were 0.05 and 5 mg/mL, respectively. After SSPE treatment, cell membrane permeability changes, zeta potential decrease and genomic DNA lysis occurred in E. coli, which indicated it exerted bacteriostatic effects either independently or simultaneously by destroying the cell membrane and genomic DNA. These findings indicated that SSPE has potential to be a natural antiseptic.

Phylogenetic comparative analysis: Chemical and biological features of caseins (alpha-S-1, alpha-S-2, beta- and kappa-) in domestic dairy animals.

Caseins determine the physicochemical, physiological, and biological characteristics of milk. Four caseins—alpha-S-1, alpha-S-2, beta, and kappa—were analyzed phylogenetically and in silico and characterized regarding chemical, antimicrobial, and antioxidant features in five dairy animals: Arabian camels, sheep, goats, cattle, and water buffalos. The sequence of full-length amino acids of the four caseins for the five species was retracted from the NCBI GenBank database. Multiple sequence alignment is used to examine further the candidate sequences for phylogenetic analysis using Clustal X and NJ-Plot tools. The results revealed that sheep and goats possess strong similarities (98.06%) because of their common ancestor. The same was observed with cattle and water buffalos (96.25%). The Arabian camel was located in a single subclade due to low similarity in casein residues and compositions with other dairy animals. Protein modeling showed that alpha-S1- and alpha-S2-caseins possess the highest number of phosphoserine residues. The in silico computed chemical properties showed that β-casein recorded highest hydrophobicity index and lowest basic amino acid content, while α-S2-casein showed the opposite. The computed biological parameters revealed that α-S2-casein presented the highest bactericidal stretches. Only Arabian camel β-casein and k-casein showed one bactericidal stretches. The analysis also revealed that β-casein, particularly in Arabian camels, possesses the highest antioxidant activity index. These results support the importance of the bioinformatics resources to determine milk casein micelles' chemical and biological activities.

Strong Selectional Forces Fine-Tune CpG Content in Genes Involved in Neurological Disorders as Revealed by Codon Usage Patterns.

Neurodegenerative disorders cause irreversible damage to the neurons and adversely affect the quality of life. Protein misfolding and their aggregation in specific parts of the brain, mitochondrial dysfunction, calcium load, proteolytic stress, and oxidative stress are among the causes of neurodegenerative disorders. In addition, altered metabolism has been associated with neurodegeneration as evidenced by reductions in glutamine and alanine in transient global amnesia patients, higher homocysteine-cysteine disulfide, and lower methionine decline in serum urea have been observed in Alzheimer’s disease patients. Neurodegeneration thus appears to be a culmination of altered metabolism. The study’s objective is to analyze various attributes like composition, physical properties of the protein, and factors like selectional and mutational forces, influencing codon usage preferences in a panel of genes involved directly or indirectly in metabolism and contributing to neurodegeneration. Various parameters, including gene composition, dinucleotide analysis, Relative synonymous codon usage (RSCU), Codon adaptation index (CAI), neutrality and parity plots, and different protein indices, were computed and analyzed to determine the codon usage pattern and factors affecting it. The correlation of intrinsic protein properties such as the grand average of hydropathicity index (GRAVY), isoelectric point, hydrophobicity, and acidic, basic, and neutral amino acid content has been found to influence codon usage. In genes up to 800 amino acids long, the GC3 content was highly variable, while GC12 content was relatively constant. An optimum CpG content is present in genes to maintain a high expression level as required for genes involved in metabolism. Also observed was a low codon usage bias with a higher protein expression level. Compositional parameters and nucleotides at the second position of codons played essential roles in explaining the extent of bias. Overall analysis indicated that the dominance of selection pressure and compositional constraints and mutational forces shape codon usage.

Ultrasonication promotes extraction of antioxidant peptides from oxhide gelatin by modifying collagen molecule structure

This study primarily explored the internal mechanism underlying the ultrasonication-induced release of antioxidant peptides. An oxhide gelatin solution was treated ultrasonically (power = 200, 300, and 400 W), followed by enzymatic hydrolysis and structural and morphological analysis. The results showed that ultrasonication increased not only the degree of hydrolysis (DH) and protein recovery rate of the oxhide gelatin but also the ABTS radical scavenging, DPPH radical scavenging, ferrous chelating, and ferric reducing activities of its hydrolysate. The oxhide gelatin hydrolysate treated with 300-W ultrasonication had the maximum antioxidant activities. Ultrasonication inhibited hydrogen bond formation, reduced the crosslinking between collagen molecules, transformed part of the folded structure into a helical structure, and lowered the thermal stability of collagen molecules. The micromorphological analysis revealed that ultrasonication caused the gelatin surface to become loose and develop cracks, and as the power of the ultrasonication increased, the repetition interval distance (dÅ) also increased. Moreover, ultrasonication improved the solubilization, surface hydrophobicity, and interface characteristics and increased the content of basic and aromatic amino acids in the hydrolysate. In conclusion, ultrasonication modifies the protein structure, which increases the enzyme’s accessibility to the peptide bonds and further enhances antioxidant peptide release. These findings provide new insights into the application of ultrasonication in the release of antioxidant peptides.

ВМІСТ АМІНОКИСЛОТ У ЗЕРНІ ПШЕНИЦІ ОЗИМОЇ ЗАЛЕЖНО ВІД СОРТУ

The amino acid content of soft wheat grain was analyzed depending on the variety. It was found that the content of lysine, leucine, phenylalanine, tyrosine and cystine varies the most from the weather conditions of growing season. The total weight of amino acids varies from 14,01 to 17,46 % of grain depending on the variety of soft wheat. The share of indispensable amino acids is 27–29 % of their total mass. However, the sum content of indispensable amino acids varies significantly depending on the variety and line – from 3,81 to 5,10 %. The highest content of phenylalanine (0.55 %), lysine (0.51 %) and leucine (0.47 %) in the grain of soft wheat Panonicus (st) variety was found. The lowest methionine content is 0.1 %. The remaining amino acids ranged from 0,39 to 0,46 %. Among the dispensable amino acids, there is the highest content of glutamine (3,54 %) and proline (1.11 %), and the lowest content of cystine (0.1 %). The variation coefficient of the samples over the years of research was average for the amino acids serine, glutamine, glycine and arginine – low, histidine, asparagine and methionine – medium, and for the rest - high,. It is obvious that the content of amino acids also varies significantly depending on the weather conditions of the growing season of winter wheat. The content of indispensable amino acids in the grain of Kulundinka soft wheat varied from 0.16 to 0.95 %. The content of threonine (0,78 %) and leucine(0,95 %) was the highest, the content of methionine was the lowest – 0.16 %. The content of other indispensable amino acids ranged from 0,50 to 0,74 %. The content of dispensable amino acids ranged 0,22–4,03 %. The highest content was of proline (1,67 %) and glutamine (4,03 %). The content of other dispensable amino acids varied from 0,80 до 1,12 %. It was found that the content of basic amino acids in wheat grain of P 7 soft line varied from 0,09 to 3,92 %. Thus, the content of indispensable amino acids is dominated by threonine, lysine, valine and leucine (0,54–0,78 %). Among the indispensable are proline, asparagine, and glutamine (1,07–3,92 %). The lowest content among indispensable amino acids was characterized by methionine (0.09 %), among dispensable – cystine (0,27 %). The grain of Kulundinka wheat variety and P 7 line obtained by hybridization of Triticum aestivum L. / Triticum spelta L. has the highest number of indispensable amino acids, which are recommended to be used to obtain high-quality grain.

Local strong acids: A driving force for metastasis

Carcinogenesis was postulated as the result of the local buildup of strong acids such as hydrogenchloride which may trigger metastasis. A previous study revealed that bicarbonate raised tumor pH and suppressed metastases. The phosphate groups in DNA on neutrophil extracellular traps possess hydrogen bonding capacity and can accept protons. The proteins commonly found in neutrophil extracellular traps such as CCDC25, myeloperoxidase (MPO), histone H3, peptidylarginine deiminase 4 (PAD4) possess basic amino acid content at about 20.2%, 12.8%, 24.3% and 13.0% respectively, which attracts anions such as chloride. The striking 20.2% basic amino acid content in CCDC25 is similar to that of typical oncoproteins. Local hydrogenchloride may be the dominant impetus for metastasis, accounting for the anticancer effects of virtually all weak organic acids, acetic acid and lactic acid in particular.

The amino acid transporter AAP1 mediates growth and grain yield by regulating neutral amino acid uptake and reallocation in Oryza sativa.

Nitrogen (N) is a major element necessary for crop yield. In most plants, organic N is primarily transported in the form of amino acids. Here, we show that amino acid permease 1 (AAP1) functions as a positive regulator of growth and grain yield in rice. We found that the OsAAP1 gene is highly expressed in rice axillary buds, leaves, and young panicles, and that the OsAAP1 protein is localized to both the plasma membrane and the nuclear membrane. Compared with the wild-type ZH11, OsAAP1 overexpression (OE) lines exhibited increased filled grain numbers as a result of enhanced tillering, while RNAi and CRISPR (clustered regularly interspaced short palindromic repeat; Osaap1) knockout lines showed the opposite phenotype. In addition, OsAAP1-OE lines had higher concentrations of neutral and acidic amino acids, but lower concentrations of basic amino acids in the straw. An exogenous treatment with neutral amino acids promoted axillary bud outgrowth more strongly in the OE lines than in the WT, RNAi, or Osaap1 lines. Transcriptome analysis of Osaap1 further demonstrated that OsAAP1 may affect N transport and metabolism, and auxin, cytokinin, and strigolactone signaling in regulating rice tillering. Taken together, these results support that increasing neutral amino acid uptake and reallocation via OsAAP1 could improve growth and grain yield in rice.

Antioxidant and antibacterial activity and in vitro digestion stability of cottonseed protein hydrolysates

In this study, five fractions (F–I to F–V) were successfully isolated from cottonseed protein hydrolysates (CPH) by using ion exchange resin system, and proved to be mainly composed of peptides with molecular weights less than 1 kDa by size exclusion high performance liquid chromatography (SEC-HPLC). All fractions possessed the DPPH radical and ABTS radical cation scavenging abilities. However, the antibacterial experiment revealed F–I and CPH had no inhibition against E. coli. By analyzing the composition of amino acids, the antioxidant and antibacterial activities were found to be positively correlated with basic amino acid contents (Arg and Lys), but negatively correlated with acidic residual (Glu and Asp). Furthermore, the in vitro digestion had slightly effects on antibacterial activity of the fractions (CPH, Fraction I-Ⅴ), while it showed great impacts on the antioxidant capacity. The work here provided basic theory and a new strategy for preparing bifunctional peptides from cottonseed protein, which could be used as an alternative in the functional food formulations.

Fractionation pH of bambara groundnut (Vigna subterranea) protein impacts the degree of complexation with gum arabic

Bambara groundnut is a protein-rich legume of African origin. This study investigated the influence of fractionation pH on degree of complexation of bambara protein isolate (BPI) with gum arabic (GA). BPI extracted at pH 2, pH 7, pH 9 and by the traditional salt solubilisation method were complexed with GA. BPI-GA complexes appeared as spherical particles (average size: 100–200 nm) that were aggregated. Optimal pHs of biopolymer interactions decreased (pHopt: 4.8 to 2.9) as protein extraction pH became more acidic. pH 2 fraction had the lowest coacervates yield (41%). ζ-potential profiles of protein fractions displayed similar pH dependent patterns, but with different pHs of net neutrality. The pH 2 fraction showed a high molecular weight protein (100 kDa), which was absent in other fractions. It also contained the highest content of basic amino acids. Protein extraction pH could be manipulated to produce better acid-stable structures on complexation with polysaccharides.

Proteomic investigation on bio-corona of functionalized multi­walled carbon nanotubes

BackgroundThe formation of bio-corona, due to adsorption of biomolecules onto carbon nanotubes (CNTs) surface in a physiological environment, may lead to a modified biological “identity” of CNTs, contributing to determination of their biocompatibility and toxicity. MethodsMulti-walled carbon nanotubes surfaces (f-MWCNTs) were modified attaching acid and basic chemical functions such as carboxyl (MWCNTs-COOH) and ammonium (MWCNTs-N) groups respectively. The investigation of interactions between f-MWCNTs and proteins present in biological fluids, like human plasma, was performed by electrophoretic separation (SDS-PAGE) and mass spectrometry analysis (nLC-MS/MS). ResultsA total of 52 validated proteins was identified after incubation of f-MWCNTs in human plasma. 86% of them was present in bio-coronas formed on the surface of all f-MWCNTs and 29% has specifically interacted with only one type of f-MWCNTs. ConclusionsThe evaluation of proteins primary structures, present in all bio-coronas, did not highlight any correlation between the chemical functionalization on MWCNTs and the content of acid, basic and hydrophobic amino acids. Despite this, many proteins of bio-corona, formed on all f-MWCNTs, were involved in the inhibitor activity of serine- or cysteine- endopeptidases, a molecular function completely unrevealed in the human plasma as control. Finally, the interaction with immune system's proteins and apolipoproteins has suggested a possible biocompatibility and a favored bio-distribution of tested f-MWCNTs. General significanceConsidering the great potential of CNTs in the nanomedicine, a specific chemical functionalization onto MWCNTs surface could control the protein corona formation and the biocompatibility of nanomaterials.

CHANGES OF CONTENT OF FREE AMINO ACIDS IN GRAINS OF FOREST GROWING EASTERS OF EASTER TRANSBAIKALIA IN PULLING IN OSMOSITIC STRESS

In the course of studying the content of free amino acids in dry and germinating grains of wild cereals, some biochemical features of their dynamics were revealed depending on the osmotic pressure. In most species, except Agropyron cristatum, a significant increase in the concentration of amino acids occurred in the control on the first day after the start of the experiment; in the subsequent period, their decrease was observed. For Agropyron cristatum, a decrease in the index and a smooth increase after the first day were observed. Under the influence of osmolyte, the tendency to mobilize amino acids has changed and in some species (Stipa krylovii, Melica virgata, Melica turczaninowiana) the maximum amounts were observed on the first day from the beginning of the experiment, in the others to the second day. The total amount of free amino acids in the control and in the test was not significantly different. There was also a rapid mobilization of proteinogenic amino acids with increasing osmotic stress for the widespread Stipa krylovii and Agropyron cristatum in the region. A similar trend was noted for the xerophyte Tripogon chinensis. For grasses with a narrow ecological niche, which are characterized by xeromesophilia, osmotic stress suppressed the rapid mobilization of free amino acids. The content of individual groups of amino acids under the influence of osmotic stress was characterized by significant differences for species of the Melica genus in the number of acidic amino acids, for Tripogon chinensis an increase in the content of basic amino acids, and for Agropyron cristatum by a decrease in their concentration.

ОБОСНОВАНИЕ РЕЦЕПТУРНОГО СОСТАВА И ТЕХНОЛОГИЧЕСКИХ ОСОБЕННОСТЕЙ ПРОИЗВОДСТВА СУХИХ СМЕСЕЙ ДЛЯ ПРОИЗВОДСТВА БЕЗГЛЮТЕНОВЫХ МУЧНЫХ КУЛИНАРНЫХ ИЗДЕЛИЙ

The material on the feasibility and development of dry culinary gluten-free mixtures for pancakes preparation is presented. The main raw material is rice flour, soybean, corn and amaranth, as well as skimmed milk powder and egg powder. The analysis of the prevalence of the celiac disease among the population is carried out. The need to expand the range of specialized products that do not contain gluten for patients with celiac diseases is shown. The amino acid composition of gluten-free flour is studied. The amino acid composition of protein is one of the important indicators characterizing its nutrition value. Based on the analysis of amino acid composition it is shown that it is advisable to use two types of flour simultaneously in the recipe of dry mixtures for the production of gluten-free pancakes, since this will help to balance the complementary composition of the protein. The recipe of dry mixtures for the production of gluten-free pancakes has been selected according to the organoleptic characteristics and taking into account the content of basic amino acids in flour to ensure the functional properties of the products. A comparative evaluation has shown that the best organoleptic indicators are at the mixture of rice and amaranth flour due to the pleasant smell, taste and aftertaste of amaranth flour. The basic technology of production of dry gluten-free mixtures for pancakes has been developed, providing packaging in cardboard boxes with an inner package of a combined polymeric material, filling the inner bag with nitrogen and hermetically sealed, nitrogen protects the content of the package from oxidation and melanoidin formation processes. Regulated indicators of nutrition value of the developed product characterizing its functional properties are established.

The amino-terminal hydrophilic region of the vacuolar transporter Avt3p is dispensable for the vacuolar amino acid compartmentalization of Schizosaccharomyces pombe.

Avt3p, a vacuolar amino acid exporter (656 amino acid residues) that is important for vacuolar amino acid compartmentalization as well as spore formation in Schizosaccharomyces pombe, has an extremely long hydrophilic region (approximately 290 amino acid residues) at its N-terminus. Because known functional domains have not been found in this region, its functional role was examined with a deletion mutant avt3(∆1-270) expressed in S. pombe avt3∆ cells. The deletion of this region did not affect its intracellular localization or vacuolar contents of basic amino acids as well as neutral ones. The defect of avt3Δ cells in spore formation was rescued by the expression of avt3+ but was not completely rescued by the expression of avt3(∆1-270). The N-terminal region is thus dispensable for the function of Avt3p as an amino acid exporter, but it is likely to be involved in the role of Avt3p under nutritional starvation conditions.

Positive selection in octopus haemocyanin indicates functional links to temperature adaptation.

BackgroundOctopods have successfully colonised the world’s oceans from the tropics to the poles. Yet, successful persistence in these habitats has required adaptations of their advanced physiological apparatus to compensate impaired oxygen supply. Their oxygen transporter haemocyanin plays a major role in cold tolerance and accordingly has undergone functional modifications to sustain oxygen release at sub-zero temperatures. However, it remains unknown how molecular properties evolved to explain the observed functional adaptations. We thus aimed to assess whether natural selection affected molecular and structural properties of haemocyanin that explains temperature adaptation in octopods.ResultsAnalysis of 239 partial sequences of the haemocyanin functional units (FU) f and g of 28 octopod species of polar, temperate, subtropical and tropical origin revealed natural selection was acting primarily on charge properties of surface residues. Polar octopods contained haemocyanins with higher net surface charge due to decreased glutamic acid content and higher numbers of basic amino acids. Within the analysed partial sequences, positive selection was present at site 2545, positioned between the active copper binding centre and the FU g surface. At this site, methionine was the dominant amino acid in polar octopods and leucine was dominant in tropical octopods. Sites directly involved in oxygen binding or quaternary interactions were highly conserved within the analysed sequence.ConclusionsThis study has provided the first insight into molecular and structural mechanisms that have enabled octopods to sustain oxygen supply from polar to tropical conditions. Our findings imply modulation of oxygen binding via charge-charge interaction at the protein surface, which stabilize quaternary interactions among functional units to reduce detrimental effects of high pH on venous oxygen release. Of the observed partial haemocyanin sequence, residue 2545 formed a close link between the FU g surface and the active centre, suggesting a role as allosteric binding site. The prevalence of methionine at this site in polar octopods, implies regulation of oxygen affinity via increased sensitivity to allosteric metal binding. High sequence conservation of sites directly involved in oxygen binding indicates that functional modifications of octopod haemocyanin rather occur via more subtle mechanisms, as observed in this study.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-015-0411-4) contains supplementary material, which is available to authorized users.

Emerging roles for HMGB1 protein in immunity, inflammation, and cancer.

High-mobility group box 1 (HMGB1) protein is a member of the highly conserved non-histone DNA binding protein family. First identified in 1973, as one of a group of chromatin-associated proteins with high acidic and basic amino acid content, it was so named for its characteristic rapid mobility in polyacrylamide gel electrophoresis. HMGB1 was later discovered to have another function. It is released from a variety of cells into the extracellular milieu to act on specific cell-surface receptors. In this latter role, HMGB1 is a proinflammatory cytokine that may contribute to many inflammatory diseases, including sepsis. Therefore, HMGB1 regulates intracellular cascades influencing immune cell functions, including chemotaxis and immune modulation. The bioactivity of the HMGB1 is determined by specific posttranslational modifications that regulate its role in inflammation and immunity. During tumor development, HMGB1 has been reported to play paradoxical roles in promoting both cell survival and death by regulating multiple signaling pathways. In this review, we focus on the role of HMGB1 in physiological and pathological responses, as well as the mechanisms by which it contributes to immunity, inflammation, and cancer progression.

Bp-13 PLA2: Purification and Neuromuscular Activity of a New Asp49 Toxin Isolated from Bothrops pauloensis Snake Venom.

A new PLA2 (Bp-13) was purified from Bothrops pauloensis snake venom after a single chromatographic step of RP-HPLC on μ-Bondapak C-18. Amino acid analysis showed a high content of hydrophobic and basic amino acids and 14 half-cysteine residues. The N-terminal sequence showed a high degree of homology with basic Asp49 PLA2 myotoxins from other Bothrops venoms. Bp-13 showed allosteric enzymatic behavior and maximal activity at pH 8.1, 36°–45°C. Full Bp-13 PLA2 activity required Ca2+; its PLA2 activity was inhibited by Mg2+, Mn2+, Sr2+, and Cd2+ in the presence and absence of 1 mM Ca2+. In the mouse phrenic nerve-diaphragm (PND) preparation, the time for 50% paralysis was concentration-dependent (P < 0.05). Both the replacement of Ca2+ by Sr2+ and temperature lowering (24°C) inhibited the Bp-13 PLA2-induced twitch-tension blockade. Bp-13 PLA2 inhibited the contractile response to direct electrical stimulation in curarized mouse PND preparation corroborating its contracture effect. In biventer cervicis preparations, Bp-13 induced irreversible twitch-tension blockade and the KCl evoked contracture was partially, but significantly, inhibited (P > 0.05). The main effect of this new Asp49 PLA2 of Bothrops pauloensis venom is on muscle fiber sarcolemma, with avian preparation being less responsive than rodent preparation. The study enhances biochemical and pharmacological characterization of B. pauloensis venom.