Cholesterol Oxidase Research Articles

SUN-664 Effects of Acute Hyperglycemia on Monocytes in Type 2 Diabetes

Background: Type 2 diabetes is linked to accelerated atherosclerosis, however the mechanisms behind this association are unclear. Inadequate glycemic control is an important contributor for cardiovascular disease (CVD). Episodic hyperglycemia as a surrogate for glycemic variability (GV) promotes monocyte adhesion and increases proinflammatory monocytes within plaques of patients with diabetes. Monocytes are precursors to macrophages which play a vital role in atherosclerosis and are capable of delivering cholesterol content to plaques. Therefore, elucidating the mechanism by which acute hyperglycemia promotes proatherogenic monocytes in diabetes can lead to novel therapies slowing atherosclerosis progression in these patients. Methods: To assess the effects of acute hyperglycemia on monocyte cholesterol metabolism, we isolated monocytes from 28 patients with Type 2 diabetes cultured for 2 and 6 hours in normoglycemic (90mg/dL) or hyperglycemic media (300mg/dL). Cholesterol content was measured by lipid extraction and fluorometric cholesterol oxidase assay. Cholesterol uptake was assessed by incubating monocytes with Dil-oxidized LDL (Dil-OxLDL). Cholesterol synthesis was performed by incubating monocytes with 2-14C-Acetate in both glycemic conditions for 6 hours followed by lipid saponification, and separated via TLC on silica gel plates. Cholesterol efflux was assessed by labeling cells with 3H-Cholesterol-OxLDL in both glycemic conditions for 6 hours followed by APO-A1 or HDL stimulation for 4 hours. Results: Acute hyperglycemia for 2 and 6 hours induced foamy monocytes with increased total cholesterol content (22 and 32%, respectively), cholesterol ester (40% and 43%, respectively), and free cholesterol content (14% and 25%, respectively) due to enhanced DiI-OxLDL uptake. There was no significant increase in monocyte cholesterol synthesis or cholesterol efflux after stimulation with HDL or APO A-1. Conclusions: Increased monocyte cholesterol content during acute hyperglycemia is a potential mechanism promoting atherosclerosis in patients with Type 2 diabetes.

Interaction of gold nanoparticles with cholesterol oxidase enzyme in bionanocomplex\u2014determination of the protein structure by Fourier transform infrared spectroscopy

The bionanocomplexes of proteins and nanoparticles are promising bionanomaterials for medical purposes like the sensitive and the selective diagnostic devices, as well as, the modern therapeutic agents. The presence of the noble metals allows for obtaining the plasmonic effect and for generating the surface-enhanced Raman scattering phenomenon (SERS). The knowledge of the nanoparticle interaction with the protein molecule is extremely necessary for the development of the suitable product. The interaction of the bionanocomplex components can cause the conformational changes in the protein structure and the modification of surface properties of the nanoparticles. In the case of the binding of the gold nanoparticles with the enzymes, it is critical to preserve the catalytic activity, which is connected with maintaining the proper molecule structure. In the presented study, the Fourier transform infrared spectroscopy was used for the investigation of the interaction and the structural properties of the cholesterol oxidase (ChOX)—the gold nanoparticles bionanocomplex. The ChOX is one of the most important enzymes for the medical diagnostics and the promising antibacterial agent. The infrared spectra of the AuNP-ChOX bionanocomplex and the ChOX in different forms (the solid and the suspended in the buffer) are presented and discussed. The obtained spectra include the considerable number of the absorption lines identified and attributed to the corresponding chemical bonds and the functional groups of the protein. The analysis of the obtained infrared spectra revealed the important information about the changes of the protein structure after the immobilization on the gold nanoparticles. Moreover, it allows to recognize the differences in the structure of the protein in a different environment, which is of great importance in the context of bionanotechnology.

High Performance Molecular Detection Biosensor Using Plasmonic Spiral Nanoantenna Based on Optical Fiber.

Biomedical sensor that sense different molecules with a high refractive index sensitivity is proposed in this work. Plasmonic nanospiral antenna is mounted on a top surface of an optical fiber to reflect the incident optical signal back to the fiber. The reflected signal depends on the nanospiral antenna material, dimensions and the surrounding medium. Using streptavidin molecule, the nanospiral antenna have been simulated based on finite difference time domain method to optimize its dimensions. The optimum dimensions are 10 nm, 55 nm and 40 nm for inner-outer thicknesses and height respectively. The introduced biosensor can detect different molecules based on surface plasmonic resonance, which depends on the shifting of the peak wavelength according to the molecules type. The detected molecules are Streptavidin, Urease, Uricase molecules and Glucose oxidase and Cholesterol oxidase enzymes with a high sensitivity. The maximum refractive index sensitivity is obtained when sensing cholesterol oxidase molecules with 3028 nm/RIU at 3.58 μm peak wavelength. Figure of merit and quality factor are also calculated for all detected molecules. Finally, electric field and optical power, before and after binding, of the reflected signal are illustrated and discussed.

Identification of cholesterol-assimilating actinomycetes strain and application of statistical modeling approaches for improvement of cholesterol oxidase production by Streptomyces anulatus strain NEAE-94

BackgroundCholesterol oxidase biosensors have been used to determine the level of cholesterol in different serum and food samples. Due to a wide range of industrial and clinical applications of microbial cholesterol oxidase, isolation and identification of a new microbial source (s) of cholesterol oxidase are very important.ResultsThe local isolate Streptomyces sp. strain NEAE-94 is a promising source of cholesterol oxidase. It was identified based on cultural, morphological and physiological characteristics; in addition to the 16S rRNA sequence. The sequencing product had been deposited in the GenBank database under the accession number KC354803. Cholesterol oxidase production by Streptomyces anulatus strain NEAE-94 in shake flasks was optimized using surface response methodology. The different process parameters were first screened using a Plackett-Burman design and the parameters with significant effects on the production of cholesterol oxidase were identified. Out of the 15 factors screened, agitation speed, cholesterol and yeast extract concentrations had the most significant positive effects on the production of cholesterol oxidase. The optimal levels of these variables and the effects of their mutual interactions on cholesterol oxidase production were determined using Box-Behnken design. Cholesterol oxidase production by Streptomyces anulatus strain NEAE-94 was 11.03, 27.31 U/mL after Plackett-Burman Design and Box-Behnken design; respectively, with a fold of increase of 6.06 times compared to the production before applying the Plackett-Burman design (4.51 U/mL).ConclusionsMaximum cholesterol oxidase activity was obtained at the following fermentation conditions: g/L (cholesterol 4, yeast extract 5, NaCl 0.5, K2HPO4 1, FeSO4.7H2O 0.01, MgSO4.7H2O 0.5), pH 7, inoculum size 4% (v/v), temperature 37°C, agitation speed of 150 rpm, medium volume 50 mL and incubation time 5 days.

Medium Optimization by Response Surface Methodology for Improved Cholesterol Oxidase Production by a Newly Isolated Streptomyces rochei NAM-19 Strain.

Cholesterol oxidase is an alcohol oxidoreductase flavoprotein with wide biotechnological applications. The current work describes the isolation of a potential cholesterol oxidase producing streptomycete from Egyptian soil. The isolated strain produced cholesterol oxidase in submerged culture using a medium containing glucose, yeast extract, malt extract, and CaCO3 with the addition of cholesterol as an inducer. The isolated strain was identified as Streptomyces rochei NAM-19 based on 16S rRNA sequencing and phylogeny. Optimization of cholesterol oxidase production has been carried out using response surface methodology. The Plackett-Burman design method was used to evaluate the significant components of the production medium followed by Box-Behnken experimental design to locate the true optimal concentrations, which are significantly affecting enzyme production. Results showed that the predicted enzyme response could be closely correlated with the experimentally obtained production. Furthermore, the applied optimization strategy increased volumetric enzyme production by 2.55 times (65.1 U/mL) the initial production obtained before medium optimization (25.5 U/mL).

Functionalized magnetic nanomaterials for electrochemical biosensing of cholesterol and cholesteryl palmitate.

Synthesis and functionalization of magnetite nanoparticles (Fe3O4) was achieved with the view to covalently bind both cholesterol oxidase and cholesterol esterase biorecognition agents for the development of free and total cholesterol biosensors. Prior to enzyme attachment, Fe3O4 was functionalized with 3-aminopropyltriethoxysilane (APTES) and polyamidoamine (PAMAM) dendrimer. Characterization of the material was performed by FT-IR and UV spectroscopy, SEM/EDX surface analysis and electrochemical investigations. The response to cholesterol and its palmitate ester was examined using cyclic voltammetry. Optimum analytical performance for the free cholesterol biosensor was obtained using APTES-functionalized magnetite with a sensitivity of 101.9μAmM-1cm-2, linear range 0.1-1mM and LOD of 80μM when operated at 37°C. In the case of the total cholesterol biosensor, the best analytical performance was obtained using PAMAM dendrimer-modified magnetite with sensitivity of 73.88μAmM-1cm-2 and linear range 0.1-1.5mM, with LOD of 90μM. A stability study indicated that the free cholesterol biosensors retained average activity of 98% after 25days while the total cholesterol biosensors retained 85% activity upon storage over the same period. Graphical abstract Schematic representation of cholesterol esterase and oxidase loaded magnetic nanoparticles (Fe3O4@APTES or Fe3O4@APTES-PAMAM) generating hydrogen peroxide from cholesterol palmitate.

ZnO nanowire-based fluorometric enzymatic assays for lactate and cholesterol.

A rapid fluorometric method is described for the determination of lactate and cholesterol by using ZnO nanowires (ZnO NWs). The assay is based on the detection of the hydrogen peroxide generated during the enzymatic reactions of the oxidation of lactate or cholesterol. Taking advantage of the electrostatic interactions between the enzymes and the ZnO NWs, two bioconjugates were prepared by mixing the nanomaterial and the enzymes, viz. lactate oxidase (LOx) or cholesterol oxidase (ChOx). The enzymatically generated hydrogen peroxide quenches the fluorescence of the ZnO NWs, which have emission peaks at 384nm and at 520nm under 330nm photoexcitation. H2O2 quenches the 520nm band more strongly. Response is linear up to 1.9μM lactate concentration, and up to 1.1μM cholesterol concentration. Relative standard deviation was found to be 5%. The detection limits for lactate and cholesterol are 0.54 and 0.24μM, respectively. Graphical abstractSchematic representation of fluorescence assay based on ZnO nanowires photoluminiscence for lactate and colesterol detection.

Alteration of Membrane Cholesterol Content Plays a Key Role in Regulation of CFTR Channel Activity

CFTR has recently been shown to exist in two distinct populations in the plasma membrane of primary human bronchial epithelial (HBE) cells: one population is diffusely distributed and the other is in cholesterol-dependent lipid rafts. Cholesterol homeostasis has been found to be altered in Cystic Fibrosis patients, although some controversy remains. For example, epithelial cells expressing F508del-CFTR exhibit increased cholesterol; however, neutrophils derived from CF patients show reduced cholesterol levels in the plasma membrane. As a major membrane lipid component, cholesterol modulates the function of multiple ion channels by complicated mechanisms, including direct cholesterol-channel protein interactions, indirect changes in physical properties of the membrane, and more. Thus far, whether cholesterol directly modulates CFTR channel function remains unknown. To answer this question, we determined the effects of changing plasma membrane cholesterol levels on CFTR channel function utilizing polarized Fischer Rat Thyroid (FRT) cells and HBE cells. We found that cholesterol depletion with 5 mM methyl-β-cyclodextrin (MβCD) significantly reduced total cholesterol in FRT cells. This cholesterol reduction by MβCD significantly decreased sensitivity of WT- and P67L-CFTR forskolin (FSK)-mediated activation. This is also seen in HBE cells expressing WT-CFTR. Cholesterol modification by cholesterol oxidase and cholesterol esterase also distinctly affected activation of P67L-CFTR by FSK. In addition, alteration of cholesterol increased efficacy of VX-770, a clinically-used potentiator of CFTR, when both WT- and P67L-CFTR channels were activated at low FSK concentrations, but not at high FSK concentrations. This change in efficacy of VX-770-mediated potentiation likely reflects the apparent shift in the sensitivity of WT-CFTR to FSK after alteration of membrane cholesterol. These results demonstrate that changes in the cholesterol level of the plasma membrane significantly modulate CFTR channel function and consequently affect potentiator efficiency in CF patients.

Immobilization of Cholesterol Oxidase from Streptomyces Sp. on Magnetite Silicon Dioxide by Crosslinking Method for Cholesterol Oxidation.

Enzymatic biosensor has been paid much attention to the research fields due to its advantage in medical application. As one of the application, we determined the optimum value of cholesterol oxidase against cholesterol. In this work, we studied the behavior of cholesterol oxidation by enzymatic reaction to get the optimum condition for cholesterol oxidation. The enzyme that used were in two form, free cholesterol oxidase, and immobilized cholesterol oxidase. Cholesterol oxidase was produced from Streptomyces sp. by using solid state fermentation method and identified had high enzyme activity to be 5.12U/mL. Cholesterol oxidase was simultaneously crosslinked immobilized onto magnetite coated by silicon dioxide (M-SiO2). The support was characterized by Fourier transform infrared (FTIR) to determine the functional group of modified particle and scanning electron microscope (SEM) to observe the morphological or our prepared particle. Cholesterol oxidase sensitivity to substrate was analyzed by using HPLC with different interval time measurements. The oxidation of cholesterol by free enzyme and immobilized enzyme was also investigated. The best sensitivity of cholesterol oxidase was estimated to oxidize Cso (concentration of substrate) 1.46mM of substrate with Ce (concentration of enzyme) 20mg/mL for 180min. Final oxidation value of cholesterol by immobilized enzyme was greater than 60%. The results of this study revealed that immobilized enzyme for cholesterol oxidation was stable, reproducible, and sensitive.

The role of hydrogen atoms in redox catalysis by the flavoenzyme cholesterol oxidase.

Flavoenzymes comprise a large class of proteins that carry out a diverse range of important redox chemistry. Although X-ray crystal structures of many flavoenzymes have been determined, there are still unresolved questions regarding the actual oxidation state of the flavin cofactors in these structures due to photoreduction by the ionizing radiation of the X-ray beam during the diffraction experiment. Additionally, the ability to visualize hydrogen atoms in X-ray structures is difficult due to the weak scattering capability of these atoms. Since hydrogen atoms affect the electrostatic nature of enzyme active sites and play important roles in the chemistry of key amino acid residues, visualizing the precise positions of these atoms provides a more detailed understanding of their role in enzyme catalysis. Single crystal neutron diffraction is an alternative method to structure determination, circumventing problems associated with photoreduction of the sample thus providing a clearer view of the structural features of a flavoenzyme in different redox states. Additionally, the larger neutron scattering factors for hydrogen and deuterium atoms enables one to visualize these atoms much more easily than from X-ray scattering measurements. In this chapter we give an overview of neutron and X-ray crystallography studies on the flavoenzyme, cholesterol oxidase and how the observations of unusual hydrogen atom positions provide insight into the redox chemistry of the flavin cofactor.

The multipurpose family of flavoprotein oxidases.

This chapter represents a journey through flavoprotein oxidases. The purpose is to excite the reader curiosity regarding this class of enzymes by showing their diverse applications. We start with a brief overview on oxidases to then introduce flavoprotein oxidases and elaborate on the flavin cofactors, their redox and spectroscopic characteristics, and their role in the catalytic mechanism. The six major flavoprotein oxidase families will be described, giving examples of their importance in biology and their biotechnological uses. Specific attention will be given to a few selected flavoprotein oxidases that are not extensively discussed in other chapters of this book. Glucose oxidase, cholesterol oxidase, 5-(hydroxymethyl)furfural (HMF) oxidase and methanol oxidase are four examples of oxidases belonging to the GMC-like flavoprotein oxidase family and that have been shown to be valuable biocatalysts. Their structural and mechanistic features and recent enzyme engineering will be discussed in details. Finally we give a look at the current trend in research and conclude with a future outlook.

The effect of long-term valproic acid treatment in the level of total cholesterol among adult.

Valproic acid (VA) is the antiepileptic, antimigraine and anti-mental disturbances agent. The use of VA is correlated to metabolic rearrangements including changes of lipoproteins; however, these effects still in debate. Herewith we analyze the effect of long-term VA treatment in the level of total cholesterol among adult. Sixty (30 case groups and 30 control groups) participants were asked for venous blood collection to examine the level of total cholesterol by enzymatic cholesterol oxidase phenol 4-aminoantipyrine peroxidase. The relationship of the long-term VA treatment and the level of total cholesterol was obtained from the analysis using the logistic regression analysis. Our analysis depicts that there is a relationship between the long-term VA treatment and the level of total cholesterol (P=0.024, odds ratio 0.272, 95% confidence interval 0.088–0.844). in conclusion, the long-term VA treatment reduces the level of total cholesterol in adult.

Membrane cholesterol oxidation downregulates atrial β-adrenergic responses in ROS-dependent manner

Oxidation of membrane cholesterol is a hallmark of many pathological conditions, including cardiovascular diseases. Cholesterol could be oxidized in a result of free radical and enzymatic reactions. Here, we studied the effect of cholesterol oxidation by cholesterol oxidase (ChO) on responses to β-AR stimulation in isolated mouse atria. Acute exposure to ChO led to partial cholesterol oxidation without a significant change in atrial membrane cholesterol content. Pretreatment with ChO itself did not affect contractions and Ca2+ transient amplitude. However, cholesterol oxidation markedly suppressed β-AR-mediated increase in contractility and Ca2+ transient as well as NO levels. At the same time, ChO markedly facilitated β-AR-induced reactive oxygen species (ROS) production. Antioxidant and protein kinase C inhibitor prevented the depressant action of ChO on ISO-dependent contractility, Ca2+ transient and NO production. Similar effects had a selective β2-AR antagonist, which also suppressed the increase in ROS levels after ChO pretreatment. These results suggest that membrane cholesterol oxidation enhances β2-AR-dependent elevation of ROS production, leading to suppression of β-AR-mediated increase in contractility, Ca2+ transient and NO synthesis in mice atria. The oxidative cholesterol modification could contribute to disturbance in β-AR signaling in pathological conditions.

Mycobacterium tuberculosis Requires Cholesterol Oxidase to Disrupt TLR2 Signalling in Human Macrophages.

This study tested the hypothesis that Mycobacterium tuberculosis (Mtb) uses a cholesterol oxidase enzyme (ChoD) to suppress a toll-like receptor type 2- (TLR2-) dependent signalling pathway to modulate macrophages' immune response. We investigated the impact of Mtb possessing or lacking ChoD as well as TBChoD recombinant protein obtained from Mtb on the expression and activation of two key intracellular proteins involved in TLR2 signalling in human macrophages. Finally, the involvement of TLR2-related signalling proteins in an inflammatory/immunosuppressive response of macrophages to Mtb was evaluated. We demonstrate that wild-type Mtb but not the ∆choD mutant decreased the cytosolic IRAK4 and TRAF6 protein levels while strongly enhancing IRAK4 and TRAF6 mRNA levels in macrophages. Our data show that the TLR2 present on the surface of macrophages are involved in disturbing the signalling pathway by wild-type Mtb. Moreover, recombinant TBChoD effectively decreased the cytosolic level of TRAF6 and lowered the phosphorylation of IRAK4, which strongly confirm an involvement of cholesterol oxidase in affecting the TLR2-related pathway by Mtb. Wild-type Mtb induced an immunosuppressive response of macrophages in an IRAK4- and TRAF6-dependent manner as measured by interleukin 10 production. In conclusion, ChoD is a virulence factor that enables Mtb to disturb the TLR2-related signalling pathway in macrophages and modulate their response.

DYNAMICS OF LIPID EXCHANGE IN BLOOD DONOR COWS FOR THE USE OF A BIOLOGICALLY ACTIVE PREPARATION

DYNAMICS OF LIPID EXCHANGE IN BLOOD DONOR COWS FOR THE USE OF A BIOLOGICALLY ACTIVE PREPARATION

Effects of Occupational Stress on Blood Lipids, Blood Sugar and Immune Function of Doctors

We aimed to investigate the effects of occupational stress on blood lipids, blood glucose and immune function of doctors. In 2017, 1291 doctors (565 males, 726 females) in The First Hospital Affiliated with Harbin Medical University (Harbin, China) were enrolled based on the principle of convenience of sampling and cluster sampling. Questionnaires were used to investigate demographic characteristics and occupational stress related factors. Level of glycated hemoglobin was detected by immunoturbidimetric method. Concentration of triglyceride was determined by glycerol phosphate oxidase end point method. Total cholesterol concentration in serum was determined by total cholesterol oxidase end point method. Concentration of serum immunoglobulin was detected by immunoturbidimetry. Levels of glycated hemoglobin and triglyceride in high tension group were higher than those in the low tension group. Levels of IgG and IgM in high tension group were lower than those in low tension group. The risk of elevated glycated hemoglobin levels in > 50-yr-old age group was higher than that of the =<35-yr-old age group. Those in the high coping strategy group was higher in the low coping strategy group. The risk of elevated total cholesterol levels in drinkers is 1.158 times that of non-drinkers. The risk of IgG concentration reduction in smokers was 0.428 times that of non-smokers. The risk of a decrease in IgA concentration in doctors with good sleep quality is 1.527 times that of those with poor sleep quality. Occupational stress can lead to increased blood lipids and sugar levels as well suppression of immune function in doctors.

Nanotechnological advances of Lipid film-based biosensors for the rapid detection of biological compounds and toxicants

The exploration of lipid membranes for the construction of nanobiosensors has recently provided the opportunity to construct devices to monitor a wide range of compounds of biological interest. Nanobiosensor miniaturization using nanotechnological tools has given novel ways to attach a wide range of “receptors” in the lipid membrane. The lipids used to construct a lipid film-based device are dipalmiloylphosphatidylcholine {DPPC} and in some cases dipalmitoylphosphatidic acid (DPPA) which is an anionic lipid and is used to increase the sensitivity of detection. Most common “receptors” used in lipid film biosensors are enzymes such as urease, cholesterol oxidase, urecase, etc, antibodies such as D-dimer antibody and artificial or natural receptors such as saxitoxin, cholera toxin, calyx [4] arene phospjoryl receptor, etc. This chapter reviews and investigates the construction of nanobiosensors based on lipid membranes that are used to monitor various toxicants. It also exploits examples of applications with an emphasis on novel devices, new nanobiosensing techniques and nanotechnology-based transduction schemes. The compounds that can be detected are insecticides, toxins, hormones, dioxins, etc. Keywords: Lipid membrane based nanosensors; Nanoyechology; Graphene and ZnO electrodes; Food toxicants; Environmental pollutants; Clinical analysis

Purification, characterization, and biological cytotoxic activity of the extracellular cholesterol oxidase produced by Castellaniella sp. COX

A new bacterial strain producing extracellular cholesterol oxidase (ChOx) was isolated and identified as Castellaniella sp. COX. The ChOx was purified by salting-out and ion-exchange chromatography up to 10.4-fold, with a specific activity of 15 U/mg with a molecular mass of 59 kDa. The purified ChOx exhibited pH 8.0 and temperature 40°C for its optimum activity. The enzyme showed stability over a wide pH range and was most stable at pH value 7.0, and at pH 8.0, it retained almost 86% of its initial activity after 3 h of incubation at 37°C. The enzyme possessed a half-life of 8 h at 37°C, 7 h at 40°C, and 3 h at 50°C. A Lineweaver-Burk plot was calibrated to determine its Km (0.16 mM) and Vmax (18.7 μmol·mg-1 ·min-1 ). The ChOx activity was enhanced with Ca2+ , Mg2+ , and Mn2+ while it was inhibited by Hg2+ , Ba2+ , Fe2+ , Cu2+ , and Zn2+ ions. Organic solvents like acetone, n-butanol, toluene, dimethyl sulfoxide, chloroform, benzene, and methanol were well tolerated by the enzyme while iso-propanol and ethanol were found to enhance the activity of purified ChOx. ChOx induced cytotoxicity with an IC50 value of 1.78 and 1.88 U/ml against human RD and U87MG established cell lines, respectively, while broadly sparing the normal human cells.

Characterization of cholesterol oxidase from a marine Streptomyces sp. and its cytotoxicity

Abstract A marine actinobacterial strain (designated as AKHSS) capable of producing cholesterol oxidase on the enzyme indicator plates was identified as Streptomyces sp. The cell-free lysate of the strain was used for monitoring the production of cholesterol oxidase and the maximal enzyme yields were recorded at 72 h post inoculation. The cholesterol oxidase was purified using polyethylene glycol 4000 precipitation, diethylaminoethyl Sephacel anionic column chromatography and Superdex-200 gel filtration to near homogeneity. Through electron-spray ionization mass spectrometry, molecular mass of the purified enzyme was recorded as 42.84 kDa. The optimum pH of the enzyme was found to be 9 and it was stable up to 60 °C. Metal salts like MgSO4 and ZnSO4 stimulated the enzyme activity. The Vmax and Km of the purified enzyme with cholesterol as substrate were found to be 1.22 μmoles/min/mL and 0.54 mM respectively. The enzyme showed significant cytotoxicity on breast (MCF-7), nasopharyngeal (KB) and ovarian (OVCAR) cancer cell lines at very low concentrations ranging from 0.093 to 0.14 μM, as evident from MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] cell viability assay. Besides, the enzyme exhibited relatively less cytotoxicity on primary mouse embryonic fibroblast (3T3) cells. Thus, cholesterol oxidase of Streptomyces sp. AKHSS could be a potential anticancer agent.

A study on understanding the blood lipid profile of the hemodialysis patients in Al-Diwaniyah Province, Iraq

One of the most frequently worldwide recorded health conditions, is a chronic renal failure (CRF), especially in elderly individuals induced due to renal damage. Kidney damage and therefore, dialysis have several detrimental effects on the body organs and their functions. According to those effects, this study was conducted to recognize the blood lipid profile of the hemodialysis patients in Al-Diwaniyah Province, Iraq. Such determination gives assurance for overall functions of the body organs in order to place proper medical management of those levels if disturbed. From Al-Diwaniyah General Teaching Hospital, Diwaniyah City, Iraq, 68 (50, 33 males and 17 females, hemodialysis CRF (H-CRF) patients and 18, 11 males and 7 females, healthy individuals) samples of blood were collected. For revealing the levels of serum blood lipids of the participants, total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) were tested using a cholesterol oxidase method for TC and HDL-C, a glycerol kinase method for TG, and the Friedewald formula for LDL-C. The results unveiled significant (p˂0.01) higher TG levels in H-CRF patients than those in healthy individuals. In addition, HDL-C revealed significant (p˂0.01) lower levels in the H-CRF patients than those in healthy people. No significant (p˃0.01) data were observed from the TC and the LDL-C levels in both groups. This work demonstrates the level changes of the TGs and the HDL-C in the serum of the hemodialysis patients which need proper medical intervention for the correction of those levels.