Search Results (27)

Reactions of benzoquinone with amines can potentially lead to the formation of coupled merocyanine or merocyanine/polymethine systems. In this study, several diamino-substituted 1,4-benzoquinones were synthesized. The crystal structures for three derivatives bearing 2-hydroxyethylamino or 2-(2-hydroxyethoxy)ethyl)amino substituents were determined using single-crystal X-ray crystallographic analysis. A characteristic feature of all molecular structures is the presence of an extensive network of intermolecular interactions, significantly stabilized by hydrogen bonding. Additionally, changes in the optical behavior of the synthesized compounds were monitored by UV-Vis spectroscopy in the presence of Cu²⁺ and Zn²⁺ ions, followed by the addition of primary, secondary or biogenic (butane-1,4-diamine) amines. Full article

In this work, limonene-1,2-epoxide hydrolase (LEH) from Rhodococcus erythropolis was immobilized on Immobead 150P and various Purolite^® methacrylate-based carriers, and subsequently applied in the hydrolysis of cis-/trans-(+)-limonene-1,2-epoxide. The immobilization efficiency was assessed based on the recovery of activity and the immobilization yield. The best results were observed when LEH was immobilized on Purolite Lifetech^TM ECR8309M modified with glutaraldehyde and 1,4-diaminobutane, yielding a specific activity of 60.5 U·g⁻¹. The optimal temperature for enzymatic reaction increased from 40 °C (free LEH) to 60 °C following immobilization. Thermal inactivation studies revealed that the free LEH followed a simple aggregation mechanism, whereas the immobilized form conformed to a two-step deactivation model, involving an initial reversible equilibrium followed by an irreversible inactivation step. When applied in 10 reaction cycles at 30 °C the immobilized biocatalyst retained 62% of the initial activity in the presence of 10% (v/v) acetonitrile and 75% in its absence. At temperatures up to 60 °C, immobilized LEH appeared very stable, retaining more than 80% of activity at 60 °C after 6 reaction cycles. This study improves our understanding of the inactivation mechanism of LEH, and the results highlight covalent immobilization as a promising method for the thermal stabilization of LEH. Full article

The objective of this study was to evaluate the inoculation of nutrient solutions with increasing levels of putrescine on the hatchability, physiology, and performance of broilers during the initial phase. The study is composed of four treatments with increasing doses of putrescine (0.015; 0.030; 0.060, and 0.090%) and a control group. At hatch, hatchability rate; ratio between egg weight and chick weight; ratio between yolk sac, liver, breast and intestine weight, and chick weight; glycogen concentration in the liver and breast; and morphometric characteristics of the jejunum and ileum were evaluated. After hatch, 400 birds were housed in metabolic cages according to the treatments received, and feed intake, body weight gain, and feed conversion ratio were assessed at specific time points. Hatchability, chick performance at hatch, and organ weight were not affected by the inoculation of increasing levels of putrescine. Intestinal villi at hatch were higher in groups supplemented with putrescine (p < 0.001). The amounts of hepatic glycogen per gram of tissue at hatch were higher in groups with the lowest levels of putrescine and decreased with increasing doses (p = 0.017). Growth performance from 1 to 21 days was not influenced by the inoculation of putrescine. Full article

The interaction of preorganized iron(II) pivalate complexes with aromatic N-donor ligand (pyridine (py) or 2,2′-bipyridine (bpy)) and 1,4-diaminobutane (dab, putrescine) in anhydrous acetonitrile yielded a new 2D coordination polymer [Fe(piv)₂(dab)₂]_n (1, piv = Me₃CCO₂^–). The molecular structure of 1 in crystal was determined by single-crystal X-ray diffraction analysis and ATR-FTIR spectroscopy. Full article

Electrical conductimetry and dynamic light scattering (DLS) were used to investigate the aggregation behaviors of four amino acid-based surfactants (AABSs; undecanoyl-glycine, undecanoyl-l-alanine, undecanoyl-l-valine, undecanoyl-l-leucine) in the presence of five linear diamine counterions (1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane). Electrical conductimetry was used to measure the CMCs for each system, which ranged from 5.1 to 22.5 mM. With respect to counterions, the obtained CMCs decreased with increases in the interamine spacer length; this was attributed to the improved torsional binding flexibility in longer counterions. Strong linear correlations (mean R² = 0.9443) were observed between the CMCs and predicted surfactant partition coefficients (logP; water/octanol), suggesting that micellization is primarily driven by the AABS’s hydrophobicity for these systems. However, significant deviations in this linear relationship were observed for systems containing 1,2-diaminoethane, 1,4-diaminobutane, and 1,6-diaminohexane (p = 0.0774), suggesting altered binding dynamics for these counterions. pH measurements during the CMC determination experiments indicated the full deprotonation of the AABSs but did not give clear insights into the counterion protonation states, thus yielding an inconclusive evaluation of their charge stabilization effects during binding. However, DLS measurements revealed that the micellar size remained largely independent of the counterion length for counterions longer than 1,2-diaminoethane, with hydrodynamic diameters ranging from 2.2 to 2.8 nm. This was explained by the formation of charge-stabilized noncovalent dimers, with each counterion bearing a full +2 charge. Conductimetry-based estimates of the degrees of counterion binding (β) and free energies of micellization (ΔG°_M) revealed that bulky AABSs exhibit preferential binding to counterions with an even number of methylene groups. It is proposed that when these counterions form noncovalent dimers, perturbations in their natural geometries result in the formation of a binding pocket that accommodates the AABS steric bulk. While the direct application of these systems remains to be seen, this study provides valuable insights into the structure–property relationships that govern AABS aggregation. Full article

The biosynthesis of antibiotics and other secondary metabolites (also named special metabolites) is regulated by multiple regulatory networks and cascades that act by binding transcriptional factors to the promoter regions of different biosynthetic gene clusters. The binding affinity of transcriptional factors is frequently modulated by their interaction with specific ligand molecules. In the last decades, it was found that the biosynthesis of penicillin is induced by two different molecules, 1,3-diaminopropane and spermidine, but not by putrescine (1,4-diaminobutane) or spermine. 1,3-diaminopropane and spermidine induce the expression of penicillin biosynthetic genes in Penicillium chrysogenum. Proteomic studies clearly identified two different proteins that respond to the addition to cultures of these inducers and are involved in β-alanine and pantothenic acid biosynthesis. These compounds are intermediates in the biosynthesis of phosphopantetheine that is required for the activation of non-ribosomal peptide synthetases, polyketide synthases, and fatty acid synthases. These large-size multidomain enzymes are inactive in the “apo” form and are activated by covalent addition of the phosphopantetheine prosthetic group by phosphopantetheinyl transferases. Both 1,3-diaminopropane and spermidine have a similar effect on the biosynthesis of cephalosporin by Acremonium chrysogenum and lovastatin by Aspergillus terreus, suggesting that this is a common regulatory mechanism in the biosynthesis of bioactive secondary metabolites/natural products. Full article

The molecular dynamics, with an emphasis on the calorimetric and dynamic glass transitions, of non-isocyanate polyhydroxyurethanes (PHUs) produced by the equimolar polyaddition of polyether-based dicyclic carbonates (P-CCs) and various short diamines was studied. The diamine component consisted of a short aliphatic diamine (1,4-diaminobutane, DAB) and a more complex ‘characteristic’ diamine. The study was conducted to investigate (i) the chemical structure of the characteristic amine, (ii) its molar ratio, and (iii) the structure and molar mass of the P-CC. Infrared spectroscopy, differential scanning calorimetry, and broadband dielectric spectroscopy were employed. The P-CC, constituting the bulk of the systems, was the most crucial component for the glass transition. The characteristic amine influenced the glass transition as a result of its bulky structure, but also presumably as a result of the introduction of free volume and the formation of hydrogen bonds. The dynamic glass transition (α relaxation) trace in the Arrhenius plots showed a subtle change at a certain temperature that merits further study in the future. The charge mobility was fully coupled with the molecular mobility, as evidenced by dc conductivity being directly proportional to the characteristic frequency of α relaxation. The fluctuation in carbonyl units (β relaxation) was mildly affected by changes in their immediate environment. Full article

1,4-diaminobutane is widely used in the industrial production of polymers, pharmaceuticals, agrochemicals and surfactants. Owing to economic and environmental concerns, there has been a growing interest in using microbes to produce 1,4-diaminobutane. However, there is lack of research on the influence of cofactors pyridoxal phosphate (PLP) and NADPH on the synthesis of 1,4-diaminobutane. PLP serves as a cofactor of ornithine decarboxylase in the synthesis of 1,4-diaminobutane. Additionally, the synthesis of 1 mol 1,4-diaminobutane requires 2 mol NADPH, thus necessitating consideration of NADPH balance in the efficient synthesis of 1,4-diaminobutane by Escherichia coli. The aim of this study was to enhance the synthesis efficiency of 1,4-diaminobutane through increasing production of PLP and NADPH. By optimizing the expression of the genes associated with synthesis of PLP and NADPH in E. coli, cellular PLP and NADPH levels increased, and the yield of 1,4-diaminobutane also increased accordingly. Ultimately, using glucose as the primary carbon source, the yield of 1,4-diaminobutane in the recombinant strain NAP19 reached 272 mg/L·DCW, by increased 79% compared with its chassis strain. Full article

This is the first study of non-woven fabrics elaborated by melt-blowing from polymer nanocomposites made of Nylon 6 and nanoclay (Cloisite 20A) modified with an amine (1,4 diaminobutane dihydrochloride). Morphological and physical characteristics, adsorption capacity, and antibacterial properties are presented. From the X-ray diffraction (XRD) results, it was possible to observe a displacement of the signals to other 2θ angles, due to an α to ϒ phase shift. The scanning electron microscopy (SEM) images showed that the mean diameter of fiber decreased as the content of nanoclay increased. The mechanical tests showed that the tear strength force of neat nylon was 1.734 N, but this characteristic increased to 2.135 N for the sample with 0.5% modified nanoclay. The inulin adsorption efficiency of the Nylon 6/C20A 1.5% and Nylon 6/C20A 2% samples at 15 min was 75 and 74%, respectively. The adsorption capacity of Nylon 6/C20A 1.5% and Nylon 6/C20A 2% for methylene blue and methyl orange remained above 90% even after four adsorption cycles. In addition, non-woven fabrics present antibacterial activity against E. coli. Full article

A porous structure formed from sheets with cavities and two close packed structures were crystallised from building blocks prepared from 2,4-difluoronitrobenzene, a diamine linker and n-butylamine. The porous structure crystallised from a flexible building block prepared using 1,4-diaminobutane as linker. The close packed structures were prepared using either piperazine or 1,4-bis(aminomethyl)benzene as a linker and have less conformational freedom. Full article

The binding of linear diamine counterions with different methylene chain lengths to the amino-acid-based surfactants undecanoic L-isoleucine (und-IL) and undecanoic L-norleucine (und-NL) was investigated with NMR spectroscopy. The counterions studied were 1,2-ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, and 1,6-diaminohexane. These counterions were all linear diamines with varying spacer chain lengths between the two amine functional groups. The sodium counterion was studied as well. Results showed that when the length of the counterion methylene chain was increased, the surfactants’ critical micelle concentrations (CMC) decreased. This decrease was attributed to diamines with longer methylene chains binding to multiple surfactant monomers below the CMC and thus acting as templating agents for the formation of micelles. The entropic hydrophobic effect and differences in diamine counterion charge also contributed to the size of the micelles and the surfactants’ CMCs in the solution. NMR diffusion measurements showed that the micelles formed by both surfactants were largest when 1,4-diaminobutane counterions were present in the solution. This amine also had the largest mole fraction of micelle-bound counterions. Finally, the und-NL micelles were larger than the und-IL micelles when 1,4-diaminobutane counterions were bound to the micelle surface. A model was proposed in which this surfactant formed non-spherical aggregates with both the surfactant molecules’ hydrocarbon chains and n-butyl amino acid side chains pointing toward the micelle core. The und-IL micelles, in contrast, were smaller and likely spherically shaped. Full article

The degradation pattern of bacterial poly-3-hydroxybutyrate (PHB) in dimethylformamide (DMF) and dioxane solutions at 100 °C assisted by ethylenediamine, 1,4-diaminobutane and monoaminoethanol was studied. When diamines were introduced into the PHB solution in DMF in the amount of 1 mol of the reagent to 5 or 10 mol of PHB monomers, a rapid decrease in the molecular weight of the polymer was observed. The initial value of the weight average molecular weight (M_w) 840 kDa had decreased by 20–30 times within the first 10–20 min of the experiment, followed by its gradual decrease to several thousand Da. When a similar molar quantity of aminoethanol was added, the molecular weight decreased slower. PHB had been degrading much slower in the dioxane solution than in DMF. By varying the number of reagents, it was possible to reach stabilization of the M_w at 1000–3000 Da when using diamines and 8000–20,000 Da using aminoethanol. ¹H NMR analysis of the oligomers revealed of amino and amido groups forming in their structure. From the opposite end of the polymer chain, residues of 3-hydroxybutyric, crotonic and isocrotonic acids were formed during degradation. Differential scanning calorimetry indicated that after oligomerization there was a decrease in the melting point from 178 °C to 140–170 °C depending on the decrease in the molecular weight. The method proposed can be used for obtaining aminated PHB oligomers. Full article

An extreme thermophile, Thermus thermophilus, produces 16 different polyamines including long-chain and branched-chain polyamines. The composition and content of polyamines in the thermophile cells change not only with growth temperature but also with pH changes. In particular, cell growth decreased greatly at alkaline medium together with significant changes in the composition and content of polyamines. The amounts of tetraamines (spermine and its homologs) markedly decreased at alkaline pH. Thus, we knocked out the speE gene, which is involved in the biosynthesis of tetraamines, and changes of composition of polyamines with pH changes in the mutant cells were studied. Cell growth in the ΔspeE strain was decreased compared with that of the wild-type strain for all pHs, suggesting that tetraamines are important for cell proliferation. Interestingly, the amount of spermidine decreased and that of putrescine increased in wild-type cells at elevated pH, although T. thermophilus lacks a putrescine synthesizing pathway. In addition, polyamines possessing a diaminobutane moiety, such as spermine, decreased greatly at high pH. We assessed whether the speB gene encoding aminopropylagmatine ureohydrolase (TtSpeB) is directly involved in the synthesis of putrescine. The catalytic assay of the purified enzyme indicated that TtSpeB accepts agmatine as its substrate and produces putrescine due to the change in substrate specificity at high pH. These results suggest that pH stress was exacerbated upon intracellular depletion of polyamines possessing a diaminobutane moiety induced by unusual changes in polyamine biosynthesis under high pH conditions. Full article

Isotope labelling of otherwise endogenous metabolites has emerged as a powerful approach to study metabolism-related biological processes, when used in conjunction with nuclear magnetic resonance or chromatography-supported mass spectrometry. Given the advantages of metabolite tracing in uncovering metabolic pathways, there is always a need to develop new methods to generate isotopically labelled compounds. In this direction, we developed a new synthetic route to access the labelled agmatine. To access labelled agmatine, we developed a two-step method that includes the treatment of labelled cyanamide with N-Boc-1,4-butanediamine, followed by a BOC deprotection. Structural confirmation was achieved by 1DNMR, 2DNMR and IR spectroscopy. This isotopologue of agmatine can be very helpful to study the pharmacokinetics and bio-distribution of this neurotransmitter and its metabolites in vitro and in vivo or used as an internal standard in mass spectrometry measurements. Full article

Dye-sensitized solar cells transform solar light into electricity. One commonly used dye is a ruthenium complex. However, the use of ruthenium has been shown to have several disadvantages. In this study, via singular spectrum analysis using HypSpec software, we determined the formation constants and calculated individual electronic spectra of species of iron(III) with several ligands (1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 2,2′-bipyridyl, 5,5-dimethyl-2,2′-bipyridyl, 4,4′-di-tert-butyl-2,2′-bipyridyl, 1,10-phenanthroline, and 3,4,7,8-tetramethyl-1,10-phenanthroline) in methanol solution. We present a spectral comparison of the complexes reported here to the ruthenium complex: tris-(2,2′-bipyridyl)ruthenium(II). Full article