The interaction of beta-lactoglobulin with ciprofloxacin and kanamycin; a spectroscopic and molecular modeling approach.

A vast research has been conducted to find suitable and safe carriers for vital and pH-sensitive drugs including antibiotics. This article reports the use of easily accessible and abundant purified beta-lactoglobulin (ß-LG) protein as the potential carrier of widely used Kanamycin (Kana) and Ciprofloxacin (Cip) antibiotics. Spectroscopic techniques (Fluorescence, UV-vis, Circular Dichroism) combined with molecular docking were used to determine the binding mechanism of these drugs. Fluorescence studies showed moderate binding affinity with the calculated binding constants KCip = 60.1 (±0.2) × 103 M-1 and Kkana = 2.5 (±0.6) × 103 M-1 with the order of Cip > Kana. Results of UV-vis were consistent with fluorescence measurements and demonstrated a stronger complexation for Cip rather than Kana. The secondary structure of ß-LG was preserved upon interaction with Kana; however, a reduction in ß-sheet content from 39.1 to 31.9% was convoyed with an increase in α-helix from 12.8 to 20.5% due to complexation of Cip. Molecular docking studies demonstrated that preferred binding sites of these drugs are not the same and several amino acids are involved in stabilizing the interaction. Based on the achieved results, Kana and Cip can spontaneously bind to ß-LG and this protein may serve as their transport vehicle.

Effect of camel milk on blood sugar and lipid profile of patients with type 2 diabetes: a pilot clinical trial.

BACKGROUND: It has been shown that camel milk consumption has a definite decreasing effect on the prevalence of diabetes. However, most of these studies were conducted on patients with type 1 diabetes, whereas studies on patients with type 2 diabetes mellitus (T2DM) are limited. In vitro experiments have shown that camel milk was able to decrease blood glucose concentration. OBJECTIVES: The purpose of this study was to investigate effects of camel and cow milk on blood sugar, lipid profile, and blood pressure of patients with T2DM. PATIENTS AND METHODS: In a randomized single-blinded controlled clinical trial, 20 patients with T2DM were randomly allocated into two groups. Participants consumed 500 mL of either camel milk (intervention group) or cow milk (control group) daily for two months. RESULTS: Mean of insulin concentration was significantly increased from 64.59 to 84.03 pmol/L in the camel milk group during the study (P < 0.05). No significant differences were shown in fasting blood sugar, lipid profile, and blood pressure between the two groups at the end of study. There was significant increase in homeostasis model assessment of insulin resistance (HOMA-IR) during the study in both groups, but no significant difference was seen between the two groups. CONCLUSIONS: Camel milk increased insulin level in patients with T2DM and might contribute to glycemic control in T2DM.

Anticancer activity and DNA-binding properties of novel cationic Pt(II) complexes.

In this study, three structurally related cationic Pt complexes, [Pt(ppy)(dppe)]CF3CO2: C1, [Pt(bhq)(dppe)]CF3CO2: C2, and [Pt(bhq)(dppf)]CF3CO2: C3, in which ppy=deprotonated 2-phenylpyridine, bhq=deprotonated benzo[h]quinoline, dppe=bis(diphenylphosphino)ethane and dppf=1,1'-bis(diphenylphosphino)ferrocene, were used for the assessment of their anticancer activities against Jurkat and MCF-7 cancer cell lines. The Pt complexes (C1-C3) demonstrated significant level of anticancer properties, as measured using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay. Moreover, the changes in nuclear morphology with Acridine Orange (AO) staining reveal that these complexes are capable to induce apoptosis, and only C1 stimulates activity of Caspase-3 in Jurkat cancer cells. To get a better insight into the nature of binding between these cationic Pt complexes and DNA, different spectroscopic techniques and gel electrophoresis were applied. On the basis of the results of UV/vis absorption spectroscopy, CD experiment and fluorescence quenching of ethidium bromide (EB)-DNA, the interaction between DNA and the Pt complexes is likely to occur through a mixed-binding mode. Overall, the present work suggests that a controlled modification could result in new potentially antitumor complexes which can survive the repair mechanism and induce facile apoptosis.

Effect of homocysteinylation on structure, chaperone activity and fibrillation propensity of lens alpha-crystallin.

Various chemical modifications can reduce chaperone activity of α-crystallin (α-Cry) and the loss of which has been implicated in the development of cataract diseases. The side chains of lysine residues are the target of both glycation and homocysteinylation, and lysine modification by the two reactions may similarly affect the structure and function of α- Cry. In this study, α-Cry was incubated with homocysteine thiolactone (HCTL), resulting in significant protein homocysteinylation, as determined with Ellman's assay. Homocysteinylation of α-Cry resulted in the reduction in surface hydrophobicity and alpha-helix to beta-sheet transition, as observed respectively with fluorescence and circular dichroism (CD) spectroscopy. The structural alteration of homocysteinylated α-Cry was accompanied by protein aggregation, including the formation of amyloid fibrils as detected by thioflavin T (ThT) fluorescence and Congo red (CR) absorption spectroscopy. The mobility shifts of homocysteinylated α-Cry on reducing and non-reducing SDS-PAGEs suggest that disulfide cross-linking in addition to lysine modification, also plays a role in aggregation of this protein. The chaperone activities of α-Cry, namely to prevent aggregation, to assist refolding and to restore activity of thermally stressed α-glucosidase (α-Gls) were reduced after homocysteinylation. Overall, this study suggests that similar to non-enzymatic glycation, homocysteinylation of α-Cry is a risk factor for the development of cataract disorders, for instance during hyperhomocysteinemia which is linked to the various ocular pathological disorders.

The enhancing effect of homocysteine thiolactone on insulin fibrillation and cytotoxicity of insulin fibril.

In the current study both structural alteration and fibrillation of insulin were studied in the presence of homocysteine thiolactone (HCTL). The spectroscopic studies revealed that HCTL increases rate of insulin unfolding, giving rise to the appearance of solvent-exposed hydrophobic regions and induces a transition from α-helix into predominantly ß-sheet structures. Thioflavin-T fluorescence studies revealed that HCTL markedly enhanced the quantity of insulin fibril formation in both agitating and non-agitating systems. Also gel electrophoresis results suggest that HCTL accelerates the process of formation of high molecular weight insulin aggregates. Moreover, insulin fibrils obtained in the presence of HCTL and those collected earlier in the pathway of insulin fibrillation displayed improved cytotoxicity against cancer cells. The enhancement of insulin fibril formation with elevated cytotoxic properties as occurred in the presence of HCTL, may suggest this homocysteine derivative as a possible contributing factor in the pathology of insulin fibrils.

Application of adsorptive voltammetry for the detection of sub-nano molar cyclizine in biological fluids and tablets using fast Fourier transform continuous cyclic voltammetry in a flowing system.

An easy and fast Fourier transform continuous cyclic voltammetric technique (FFTCV) for monitoring of ultra trace amounts of cyclizine in a flow-injection system has been introduced in this work. The potential waveform, which was applied continuously on an Au disk microelectrode (12.5 microm in radius) consisted of the potential steps for cleaning, accumulation and potential ramp. The proposed detection method has some advantages, the greatest of which are as follows: first, it is no longer necessary to remove oxygen from the analyte solution and second, this is a very fast and appropriate technique for determination of the drug compound in a wide variety of chromatographic analysis methods. The detection limit for cyclizine was 1.8 ng ml(-1). The relative standard deviation (RSD) of the proposed technique at 5.0 x 10(-7) was 2.0 for 10 runs. The influences of pH of eluent, accumulation potential, sweep rate, and accumulation time on the determination of the cyclizine were considered. The proposed method was applied to the determination of cyclizine in a pharmaceutical preparation.

Interaction of saffron carotenoids as anticancer compounds with ctDNA, Oligo (dG.dC)15, and Oligo (dA.dT)15.

Crocin and crocetin are two important natural saffron carotenoids, which, along with dimethylcrocetin (DMC) as a semi-synthetic product, are responsible for its color. Many biological properties of saffron have been reported, among which the anticancer property is the most important. Some anticancer drugs have direct interaction with DNA, and thus the present study attempted to investigate the interaction of three major saffron carotenoids-crocin, crocetin, and DMC--with calf thymus DNA (ctDNA) and oligonucleotides. The spectrophotometric data showed some changes in ctDNA absorption spectra due to the formation of complex with saffron extract and each of these three components. Also, all the three components caused the quenching of the fluorescence emission of ctDNA-ethidium bromide complex. The Scatchard analysis of these data indicated a noncompetitive manner for quenching, which is accompanied by the outside groove-binding pattern. The circular dichroism (CD) spectra also indicated the nonintercalative binding and induction of the conformational changes, and B to C transition in ctDNA structure and then unstacking of ctDNA bases at higher concentrations of the carotenoids. The CD spectra of G.C and A.T oligonucleotides after addition of these carotenoids indicated the transition from B- to C-DNA, which is very similar to the ctDNA spectral changes. The DeltaG(H(2)O), the best parameter for the estimation of macromolecule stability, was determined for ctDNA denaturation using dodecyl trimethylammonium bromide in the absence and presence of crocin, crocetin, or DMC. Our results showed a decrease in the Delta G(H(2)O), indicating the ctDNA destabilization due to its interaction with the mentioned ligands. In conclusion, the results show that saffron and its carotenoids interact with DNA and induce some conformational changes in it. Of these carotenoids, the order of potential of interaction with DNA is crocetin > DMC >> crocin.

Conformational lock and dissociative thermal inactivation of lentil seedling amine oxidase.

The kinetics of thermal inactivation of copper-containing amine oxidase from lentil seedlings were studied in a 100 mM potassium phosphate buffer, pH 7, using putrescine as the substrate. The temperature range was between 47-60 degrees C. The thermal inactivation curves were not linear at 52 and 57 degrees C; three linear phases were shown. The first phase gave some information about the number of dimeric forms of the enzyme that were induced by the higher temperatures using the "conformational lock" pertaining theory to oligomeric enzyme. The "conformational lock" caused two additional dimeric forms of the enzyme when the temperature increased to 57 degrees C. The second and third phases were interpreted according to a dissociative thermal inactivation model. These phases showed that lentil amine oxidase was reversibly-dissociated before the irreversible thermal inactivation. Although lentil amine oxidase is not a thermostable enzyme, its dimeric structure can form "conformational lock," conferring a structural tolerance to the enzyme against heat stress.