Ca2+ binding to bovine lactoferrin enhances protein stability and influences the release of bacterial lipopolysaccharide

2002 ◽  
Vol 80 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Paola Rossi ◽  
Francesco Giansanti ◽  
Alberto Boffi ◽  
Maria Ajello ◽  
Piera Valenti ◽  
...  
Keyword(s):  
Protein Stability ◽  
Bacterial Lipopolysaccharide ◽  
Bovine Lactoferrin ◽  
Bacterial Cells ◽  
Weakly Bound ◽  
Apparent Dissociation Constant ◽  
Outer Membranes ◽  
Carboxylate Groups ◽  
Ft Ir ◽  
Phosphate Buffered Saline

Bovine lactoferrin (bLf) is known to damage the outer membrane of Gram-negative bacteria by binding to bacterial lipopolysaccharide (LPS). We report that LPS is released from bacterial outer membranes also when apo- or metal-saturated Lf is separated from bacterial cells by a dialysis membrane. This process occurs in phosphate-buffered saline with no added Ca2+ and Mg2+ and is hindered by addition of these cations. The effect of bLf is similar to that induced by EDTA and has been ascribed to chelation of Ca2+. In fact, it may be envisaged that Ca2+-binding sites on LPS have different affinities and that bLf can remove those ions that are more weakly bound. Ca2+ binding does not alter Lf iron-binding properties significantly or its UV and CD spectral features but brings about changes in the FT-IR bands due to carboxylate residues. Ca2+ binding is characterized by an apparent dissociation constant of 6 µM and a stoichiometry of 1.55 Ca2+ per Lf molecule; it enhances bLf stability towards chemical and thermal denaturation. The increase in stability takes place in both the apo- and iron-saturated forms but not in the desialilated protein, indicating that the carboxylate groups of the sialic acid residues present on two of the glycan chains are involved in Ca2+ binding.Key words: lactoferrin, calcium, antibacterial activity, lipopolysaccharides, protein stability, denaturation.

scholarly journals Synthesis, structural characterization, cytotoxicity and encapsulation studies of N,Nʹ-(1, 2-dicyano-1,2-vinylene)-bis(4-hydroxysalicylideneaminato) di(p-chlorobenzyl)tin as potential anticancer drug

2019 ◽  
Vol 42 (1) ◽  
pp. 94-101
Author(s):  
Nur Adibah Mohd Amin ◽  
Rusnah Syahila Duali Hussen ◽  
See Mun Lee ◽  
Kae Shin Sim ◽  
Suerialoasan Navanesan
Keyword(s):  
Drug Release ◽  
Cancer Cell ◽  
Cancer Cell Line ◽  
Spherical Shape ◽  
Average Diameter ◽  
Diphenyltetrazolium Bromide ◽  
Ft Ir ◽  
Phosphate Buffered Saline ◽  
Mcf 7

Abstract Two new diorganotin(IV) complexes with the general formula (RC7H6)2Sn(L) (where RC7H6 = p-ClBn, C1; and p-FBn, C2) were prepared based on the reaction of 2,3-bis(4-hydroxysalicylidene-amino)-maleic nitrile (L) with substituted dibenzyltin(IV) dichloride. The structures were confirmed by elemental analysis, Fourier transform infrared (FT-IR), proton and carbon nuclear magnetic resonance (1H and 13C NMR). They were tested against several cancer cell lines by using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. C1, which was most effective against MCF-7 breast cancer cell line, was further investigated in formulation and encapsulation studies, including drug encapsulation efficiency, particle size, morphology and in vitro drug release. An encapsulation of about 90% was achieved with particles of 128 nm average diameter. Field emission scanning electron microscopy (FESEM) confirmed a spherical shape for the encapsulated C1. The cumulative drug release over a period of 60 days in phosphate buffered saline (PBS) at pH 7.4 was 75%. Based on these results, the formulated drug has the potential of a slow release drug for cancer chemotherapy.

scholarly journals Potential Use of Silica Nanoparticles for the Microbial Stabilisation of Wine: An In Vitro Study Using Oenococcus oeni as a Model

Foods ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1338
Author(s):  
Kamila Pachnowska ◽  
Krzysztof Cendrowski ◽  
Xymena Stachurska ◽  
Paweł Nawrotek ◽  
Adrian Augustyniak ◽  
...  
Keyword(s):  
In Vitro Study ◽  
Oenococcus Oeni ◽  
Chemical Oxidation ◽  
Alternative Methods ◽  
Bacterial Cells ◽  
Silica Nanospheres ◽  
Cell Counts ◽  
Transmission Electron ◽  
Phosphate Buffered Saline

The emerging trend towards the reduction of SO2 in winemaking has created a need to look for alternative methods to ensure the protection of wine against the growth of undesired species of microorganisms and to safely remove wine microorganisms. This study describes the possible application of silica nanospheres as a wine stabilisation agent, with Oenococcus oeni (DSM7008) as a model strain. The experiment was conducted firstly on model solutions of phosphate-buffered saline and 1% glucose. Their neutralising effect was tested under stirring with the addition of SiO2 (0.1, 0.25, and 0.5 mg/mL). Overall, the highest concentration of nanospheres under continuous stirring resulted in the greatest decrease in cell counts. Transmission electron microscope (TEM) and scanning electron microscopy (SEM) analyses showed extensive damage to the bacterial cells after stirring with silica nanomaterials. Then, the neutralising effect of 0.5 mg/mL SiO2 was tested in young red wine under stirring, where cell counts were reduced by over 50%. The obtained results suggest that silica nanospheres can serve as an alternative way to reduce or substitute the use of sulphur dioxide in the microbial stabilisation of wine. In addition, further aspects of following investigations should focus on the protection against enzymatic and chemical oxidation of wine.

scholarly journals FT-IR spectroscopic characteristics of differently cultivated Escherichia coli

2009 ◽  
Vol 26 (No. 6) ◽  
pp. 458-463 ◽  
Author(s):  
Z. Filip ◽  
S. Hermann ◽  
K. Demnerová
Keyword(s):  
Escherichia Coli ◽  
Ir Spectra ◽  
Cell Mass ◽  
Bacterial Cells ◽  
Cultural Conditions ◽  
Spectroscopic Characteristics ◽  
Nitrogen Concentrations ◽  
Ft Ir ◽  
Well Differentiated ◽  
Ir Spectroscopic

FT-IR spectra were recorded of <i>Escherichia coli</i> cell mass with the aim of obtaining spectral traits possibly useful in a rapid detection and characterisation of this indicator bacterium. A well differentiated spectrum was obtained from the cell mass harvested in a stationary phase of growth, e.g., after 24 h, from a minimum nutrient broth. The cell mass, harvested either earlier or grown in nutrient solutions which contained an enhanced carbon or nitrogen concentrations delivered somewhat different IR spectra, apparently due to a higher content of nucleic acid components as related to other structural constituents of bacterial cells. Consequently, the FT-IR spectra of <i>E. coli</i>, although rather rapidly to collect, seem only capable of delivering useful and reproducible information if the cell mass is obtained under standardised cultural conditions.

Adhesion of Acidithiobacillus Caldus and Leptospirillum Ferriphilum on Pyrite and their Effect on Surface Properties of Sulfide Minerals

2009 ◽  
Vol 71-73 ◽  
pp. 449-452
Author(s):  
G. Gu ◽  
Li Jun Su ◽  
Guan Zhou Qiu ◽  
Y. Hu
Keyword(s):  
Surface Properties ◽  
Isoelectric Point ◽  
Sulfide Minerals ◽  
Ferrous Ion ◽  
Bacterial Cells ◽  
Leptospirillum Ferriphilum ◽  
Acidithiobacillus Caldus ◽  
Ft Ir ◽  
Bacterial Adsorption ◽  
Strong Ability

Acidithiobacillus caldus and Leptospirillum ferriphilum cells grown in different energy substances (ferrous ion, sulfur and pyrite) were used. The adhesion of A. caldus and L. ferriphilum cells on pyrite and their effect on pyrite surface properties were studied by adsorption, zeta-potential and FT-IR methods, and the corrosion images of pyrite interaction with bacteria were examined using atomic force microscopy. Research showed that pyrite isoelectric point (IEP) after interaction with bacterial cells shifted towards cells isoelectric point, and the shift degree in case of interaction with A. caldus was observed to be much more pronounced than for interaction with L. ferriphilum, which can be due to higher affinity of A. caldus towards pyrite. The FT-IR spectra of pyrite treated with bacterial cells revealed the presence of the cell functional groups signifying cells adsorption. Although the adsorption density of A. caldus on pyrite was higher than that of L. ferriphilum, L. ferriphilum with strong ability to oxidize ferrous ion showed better leaching efficiency than A. caldus with strong ability to oxidize sulfur for pyrite leaching. The results demonstrated that more important of indirect action (L. ferriphilum) than direct action (A. caldus) on pyrite.Introduction Bacterial adsorption to minerals is an initial step in bacterial leaching for metal recovery [1]. It has been reported that bacterial adhesion is dependent not only on the biochemical properties of the organism but also on the interfacial properties of the various interfaces existing in a bioleaching system[2].The bacteria-mineral interactions result in the changes of their surface properties. The elucidation of their alternate will be beneficial for bioleaching processes. Both Acidithiobacillus caldus and Leptospirillum ferriphilum are known for their ability to inhabit acidic environments and derive energy from oxidation of inorganic substances with natural occurrence in ore deposits and acid mine drainage and high affinity towards sulfide minerals [3-5]. In this work, the alterations of surface properties of pyrite after interaction with L. ferriphilum and A. caldus are studied, and the changes in surface properties caused by bacterial adsorption are discussed with reference to bioleaching behavior of pyrite.

scholarly journals Design and properties of a fluorescent indicator of intracellular free Na+ concentration

1988 ◽  
Vol 250 (1) ◽  
pp. 227-232 ◽  
Author(s):  
G A Smith ◽  
T R Hesketh ◽  
J C Metcalfe
Keyword(s):  
Aqueous Solubility ◽  
Ratio Method ◽  
Isosbestic Point ◽  
Buffer Solution ◽  
Acetoxymethyl Ester ◽  
Apparent Dissociation Constant ◽  
Fluorescent Indicator ◽  
Carboxylate Groups ◽  
Reporter Group ◽  
Benzenoid Ring

We have recently described a cryptand structure, FCryp-1, with appropriate properties for an indicator of intracellular free Na+ concentration using the 19F-n.m.r. chemical shift of the incorporated 5FBAPTA [1,2-bis-(2-amino-5-fluorophenoxy)ethane-NNN‘N’-tetra-acetic acid] reporter group to measure the free cytosolic Na+ concentration [(Na+]i) [Smith, Morris, Hesketh and Metcalfe (1986) Biochim. Biophys. Acta 889, 82-83]. FCryp-1 carries four carboxylate groups to confer aqueous solubility and the indicator is membrane-permeant when the carboxyls are esterified with acetoxymethyl ester groups. Here we describe the synthesis of FCryp-2 to provide a fluorescent indicator of [Na+]i. FCryp-2 retains the parent tribenzo (2:2:1) cryptand structure of FCryp-1, in which the benzenoid ring at C-21 in FCryp-1 is replaced by an indole derivative which acts as the fluorophor in FCryp-2. With excitation at 340 nm, FCryp-2 gives an emission maximum at 460 nm in the absence of Na+ which shifts to 395 nm when FCryp-2 is saturated with Na+, with an isosbestic point at 455 nm. The apparent dissociation constant of FCryp-2 in a buffer solution of 100 mM-KCl/20 mM-KH2PO4/K2HPO4, pH 7.0, at 37 degrees C is 6.0 mM and the free Na+ concentration can be measured either from the calibrated fluorescence intensity at 395 nm, which increases 25-fold when Na+ is bound to FCryp-2, or from the ratio of fluorescence intensities at 395 nm and 455 nm. The measurement of free [Na+] by either method is unaffected by K+, Ca2+ or Mg2+ in the normal intracellular concentration ranges. Free [Na+] measurements by the ratio method are unaffected by pH from 6.6 to 7.6.

scholarly journals Komplexe mit aromatischen Carbonsäuren, IV. Ca2[C6H2(COO)4]·6H2O - Eine neue Schichtstruktur/ Complexes with Aromatic Carboxylic Acids, IV. Ca2[C6H2(COO)4]·6H2O - A Novel Layer Structure

1988 ◽  
Vol 43 (8) ◽  
pp. 993-997 ◽  
Author(s):  
Christian Robl
Keyword(s):  
Hydrogen Bonds ◽  
Single Crystals ◽  
Silica Gel ◽  
Layer Structure ◽  
The Other ◽  
Water Molecules ◽  
Ring Plane ◽  
Weakly Bound ◽  
Carboxylate Groups ◽  
Oxygen Atoms

AbstractSingle crystals of Ca2[C6H2(COO)4]·6H2O were grown in aqueous silica gel. Ca2+ has CN 6+2. The coordination polyhedron is formed by three water molecules and five oxygen atoms of carboxylate groups. Six oxygen atoms are closely bound (235,9-243,9 pm), the two remaining coordination partners are considerably more remote from Ca2+ (268,2 and 273,8 pm). COO- groups chelate Ca2+ in an asymmetric manner, but the C -O bond lengths do not differ markedly (125,2-126,3 pm). The connection of Ca2+ with [C6H2(COO)4]4- leads to rigid layers. Adjacent layers are interlinked by hydrogen bonds. Those oxygen atoms which are weakly bound to Ca2+ are favoured as proton acceptors in hydrogen bonds. The COO groups are tilted differently against the C6-ring plane. One is approximately coplanar, but the other is oriented almost perpendicularly.

scholarly journals Spectroscopic Investigations of 316L Stainless Steel under Simulated Inflammatory Conditions for Implant Applications: The Effect of Tryptophan as Corrosion Inhibitor/Hydrophobicity Marker

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1097
Author(s):  
Dominika Święch ◽  
Gaetano Palumbo ◽  
Natalia Piergies ◽  
Ewa Pięta ◽  
Aleksandra Szkudlarek ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Conformational Changes ◽  
Local Environment ◽  
Protective Efficiency ◽  
Inflammatory Conditions ◽  
Protonated Amine ◽  
Short Period ◽  
316 L Stainless Steel ◽  
Ft Ir ◽  
Phosphate Buffered Saline

In this paper, the conformational changes of tryptophan (Trp) on the corroded 316 L stainless steel (SS) surface obtained under controlled simulated inflammatory conditions have been studied by Raman (RS) and Fourier-transform infrared (FT-IR) spectroscopy methods. The corrosion behavior and protective efficiency of the investigated samples were performed using the potentiodynamic polarization (PDP) technique in phosphate-buffered saline (PBS) solution acidified to pH 3.0 at 37 °C in the presence and absence of 10−2 M Trp, with different immersion times (2 h and 24 h). The amino acid is adsorbed onto the corroded SS surface mainly through the lone electron pair of the nitrogen atom of the indole ring, which adopts a more/less tilted orientation, and the protonated amine group. The visible differences in the intensity of the Fermi doublet upon adsorption of Trp onto the corroded SS surface, which is a sensitive marker of the local environment, suggested that a stronger hydrophobic environment is observed. This may result in an improvement of the corrosion resistance, after 2 h than 24 h of exposure time. The electrochemical results confirm this statement—the inhibition efficiency of Trp, acting as a mixed-type inhibitor, is made drastically higher after a short period of immersion.

scholarly journals Criteria for standartization of probiotic components in functional food products

2018 ◽  
Vol 6 (2) ◽  
pp. 457-466
Author(s):  
Andrey Sukhikh ◽  
Andrey Sukhikh ◽  
Yuliya Zakharova ◽  
Yuliya Zakharova ◽  
Arseniy Yuzhalin ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Cell Wall ◽  
Ir Spectroscopy ◽  
Functional Food ◽  
Gel Permeation Chromatography ◽  
Food Products ◽  
Chemical Study ◽  
Bacterial Cells ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

The increasing volume of consumption of probiotics and functional food products requires determination of standardized criteria for cultures and their exometabolites used in functional products manufacturing. The study was aimed at developing criteria for the estimation and standardization of exometabolites and the colony-forming ability of probiotic strains for functional food production. The work included such microbiological and physicochemical methods as GC-MS, GPC, UV, and FT-IR-spectroscopy. Based on the results of the study, the comparative analysis of the microbiological properties of probiotic Bifidobacterium strains was provided, the fatty acid composition of the cell wall was described, and the physical and chemical study of the exopolymers produced by them was carried out. According to the data of FT-IR- spectroscopy, the characteristic features of the components of the cell wall of Bifidobacterium strains were established. Bifidobacteria form the unique composition of organophosphorus structures of lipoteichoic acids, which determines the adhesive ability of strains. The authors studied the molecular weight distribution of the samples of exometabolites isolated from the nutrient medium after the cultivation of bifidobacteria, under conditions of gel-permeation chromatography. The spectral (UV, FT-IR) characteristics of the produced metabolites and their chromatographic fractions were compared. The fatty acids of the Bifidobacterium cell membrane were analyzed using the GC/MS method. The fatty acids were extracted from bacterial cells with different hydrophobicity with a mixture of chloroform and hexane. It has been established that the hydrophobicity is determined by different contents of unsaturated and branched fatty acids in the bacterial membrane. Hydrophobic bifidobacteria are the only that contain the isopentadecane (isoC15:0) and methyl-tetradecanoic (13Me-C14:0) acids. With the mean hydrophobicity, a high content of the isopalmitic (isoC16:0) and stearic (C18:0) acids was established. Low-hydrophobic strains are characterized by a low content of monounsaturated fatty acids.

Synthesis, Characterization and Properties of Poly(L-Lactic Acid-Co-α- Phenylalanine) Obtained by Direct Melting Copolymerization

2010 ◽  
Vol 152-153 ◽  
pp. 1641-1644 ◽  
Author(s):  
Pei Wang ◽  
Lian Liu ◽  
Zhi Yong Wei ◽  
Qiang Xu ◽  
Min Qi
Keyword(s):  
Lactic Acid ◽  
Degradation Rate ◽  
Stannous Chloride ◽  
Toluenesulfonic Acid ◽  
Speed Up ◽  
Ft Ir ◽  
Phosphate Buffered Saline ◽  
Direct Melting

A new poly(ester amide)s (PEA) derived from L-lactic acid and L- phenylalanine have been synthesized by melting copolymerization with p-toluenesulfonic acid (TSA), stannous chloride (SnCl2) as catalyst. The products were analyzed by NMR, FT IR. The effects of the content of L-phenylalanine on the copolymers structure were studied. Being the phosphate buffered saline (pH=7.2) as the degradation solution, it had been found that the degradation rate speed up with the increasing the content of the L- phenylalanine.

scholarly journals Radical induced damage ofMicrococcus luteusbacteria monitored using FT‒IR spectroscopy

2005 ◽  
Vol 19 (1) ◽  
pp. 17-26 ◽  
Author(s):  
Chrystelle Lorin–Latxague ◽  
Anne–Marie Melin
Keyword(s):  
Ir Spectroscopy ◽  
Culture Media ◽  
Micrococcus Luteus ◽  
Final Concentration ◽  
Antioxidant Systems ◽  
Spectral Window ◽  
Carboxylate Groups ◽  
Physico Chemical ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

Oxidative damage induced by ascorbic acid (AA) and hydrogen peroxide (H2O2) was monitored by Fourier transform infrared spectroscopy (FT‒IR); it appeared as a rapid and convenient means to follow the biochemical changes generated in the culture media of the yellow-pigmentedMicrococcus luteus. Beyond a threshold of 20 mM for AA and of 40 mM for H2O2(final concentration), antioxidant systems were overwhelmed and significant changes were observed in the bacterial spectra, particularly in the 1430–900 cm−1region; this spectral window provided large information about carboxylate groups, phosphate-carrying compounds and polysaccharides implicated in the radical process. The spectroscopic results indicated that for the same final concentration, the toxicity of H2O2was less important than that of AA towardM. luteuscells, although H2O2had a more damaging effect on proteins. Thus, FT-IR spectroscopy was an appropriate physico-chemical tool suitable in biochemical and clinical research for early characterization of any type of radical aggression, and for rapid detection of the damage intensity.

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