Relationships between the effects of redox potential, alpha-thenoyltrifluoroacetone and malonate on O(2) and H2O2 generation by submitochondrial particles in the presence of succinate and antimycin

A successful approach has been developed for the sequencing of apolipoprotein B based upon the procedure of Cleveland et al. [(1977) J. Biol. Chem. 252, 1102-1106] involving limited proteolysis in the presence of sodium dodecyl sulfate. Staphylococcus aureus protease was employed to produce large peptides which were isolated in relatively pure form by preparative gel electrophoresis. Two peptides were partially sequenced using spinning-cup microsequencing techniques. The sequences are: Peptide R2-5, -Ala-Leu-Val-Gly-Ile-Asn- Gly-Glu-Ala-Asn-Leu-Asp-Phe-Leu-Asn-Ile-Pro-Leu-Arg-Ile-Pro-Pro- Met-Arg-(Arg)-; Peptide R3-1, -Leu-Val-Ala-Lys-Pro-Ser-Val-Ser-Val-Glu- Phe-Val-Thr-Asn-Met-Gly-Ile-Ile-Pro-Lys-Phe-Ala-Arg-. Several stretches of residues suitable for the construction of oligonucleotide probes have been identified.     

Interaction of alkaline metal ions with Ca(2+)-binding sites of Ca(2+)-ATPase of sarcoplasmic reticulum: 23Na-NMR studies.

The analysis of the 23Na-NMR signal shape variations in the presence of vesicles of light sarcoplasmic reticulum (SR) shows the existence of sodium sites on the membranes with Kd values of about 10 mM. Other monovalent cations displace Na+ from SR fragments in a competitive manner according to the row K+ greater than Rb+ greater than Cs+ greater than Li+. Calcium ions also reduce Na+ binding, the Na+ desorption curve being of a two-stage nature, which, as suggested, indicates the existence of two types of Ca(2+)-sensitive Na+ binding sites (I and II). Sites of type I and II are modified by Ca2+ in submicromolar and millimolar concentrations, respectively. Analysis of sodium (calcium) desorption produced by calcium (sodium) allowed us to postulate the competition of these two cations for sites I and identity of these sites to high-affinity Ca(2+)-binding ones on the Ca(2+)-ATPase. Sites I weakly interact with Mg2+ (KappMg approximately 30 mM). Reciprocal effects of sodium and calcium on binding of each other to sites II cannot be described by a simple competition model, which indicates nonhomogeneity of these sites. A portion of sites I (approximately 70%) interacts with Mg2+ (KappMg = 3-4 mM). The pKa value of sites II is nearly 6.0. The number of sites II is three times greater than that of sites I. In addition, sites with intermediate affinity for Ca2+ were found with Kd values of 2-5 microM. These sites were revealed due to the reducing of the sites II affinity for Na+ upon Ca2+ binding to SR membranes. It can thus be concluded that in nonenergized SR there are binding sites for monovalent cations of at least three types: (1) sites I (which also bind Ca2+ at low concentrations), (2) magnesium-sensitive sites II and (3) magnesium-insensitive sites II.     

A correlation between BCL-2 modifying factor,p53 and livin gene expressions in cancer colon patients

Accumulating evidence has revealed that livin gene and BCL-2 modifying factor (BMF) gene are closely associated with the initiation and progression of colon carcinoma by activating or suppressing multiple malignant processes. Those genes that can detect colon - cancer are a promising approach for cancer screening and diagnosis. This study aimed to evaluate correlation between livin, BMF and p53 genes expression in colon cancer tissues of patients included in the study, and their relationship with clinicopathological features and survival outcome in those patients. In this study, 50 pathologically diagnosed early cancer colon patients included and their tissue biopsy with 50 matched adjacent normal tissue, and 50 adenoma tissue specimens were analyzed for livin gene and BMF gene expressions using real time PCR. The relationship of those genes expressions with clinicopathological features, tumor markers, Time to Progression and overall survival for those patients were correlated in cancer colon group. In this study, there was a significant a reciprocal relationship between over expression of livin gene and down regulation of BMF and p53 genes in colon cancer cells. Livin mRNA was significantly higher, while BMF and p53 mRNA were significantly lower in colorectal cancer tissue compared to benign and normal colon tissue specimens (P < 0.001), however, this finding was absent between colon adenomas and normal mucosa. There was a significant association between up regulation of livin and down regulation of BMF and p53 expressions with more aggressive tumor (advanced TNM stage), rapid progression with metastasis and decreased overall survival in cancer colon patients, hence these genes can serve as significant prognostic markers of poor outcome in colon cancer patients. This work highlights the role of livin, BMF and p53 genes in colorectal tumorigenesis and the applicability of using those genes as a diagnostic and prognostic markers in patients with colon carcinoma and as a good target for cancer colon treatment in the future.     

Biocides formulation of essential oils having antimicrobial activity

Essential oils of fennel, peppermint, caraway, eucalyptus, geranium and lemon were tested for their antimicrobial activities against some plant pathogenic micro-organisms (Fusarium oxysporum, Alternaria alternate, Penicilium italicum Penicilium digitatum and Botyritus cinerea). Essential oils of fennel, peppermint, caraway were selected as an active ingredient for the formulation of biocides due to their efficiency in controlling the tested micro-organisms. Successful emulsifiable concentrates (biocides) were prepared from these oils using different emulsifiers (Emulgator B.L.M. Tween20 and Tween80) and different fixed oils (sesame, olive, cotton and soybean oils). Physico-chemical properties of the formulated biocide (spontaneous emulsification, emulsion stability test, cold stability and heat stability tests as well as viscosity, surface tension and pH) were measured. The prepared biocides were ready to be tested for application in a future work as a safe pesticide against different pathogens.     

Metagenomic insights into strategies of carbon conservation and unusual sulfur biogeochemistry in a hypersaline Antarctic lake

Organic Lake is a shallow, marine-derived hypersaline lake in the Vestfold Hills, Antarctica that has the highest reported concentration of dimethylsulfide (DMS) in a natural body of water. To determine the composition and functional potential of the microbial community and learn about the unusual sulfur chemistry in Organic Lake, shotgun metagenomics was performed on size-fractionated samples collected along a depth profile. Eucaryal phytoflagellates were the main photosynthetic organisms. Bacteria were dominated by the globally distributed heterotrophic taxa Marinobacter, Roseovarius and Psychroflexus. The dominance of heterotrophic degradation, coupled with low fixation potential, indicates possible net carbon loss. However, abundant marker genes for aerobic anoxygenic phototrophy, sulfur oxidation, rhodopsins and CO oxidation were also linked to the dominant heterotrophic bacteria, and indicate the use of photo- and lithoheterotrophy as mechanisms for conserving organic carbon. Similarly, a high genetic potential for the recycling of nitrogen compounds likely functions to retain fixed nitrogen in the lake. Dimethylsulfoniopropionate (DMSP) lyase genes were abundant, indicating that DMSP is a significant carbon and energy source. Unlike marine environments, DMSP demethylases were less abundant, indicating that DMSP cleavage is the likely source of high DMS concentration. DMSP cleavage, carbon mixotrophy (photoheterotrophy and lithoheterotrophy) and nitrogen remineralization by dominant Organic Lake bacteria are potentially important adaptations to nutrient constraints. In particular, carbon mixotrophy relieves the extent of carbon oxidation for energy production, allowing more carbon to be used for biosynthetic processes. The study sheds light on how the microbial community has adapted to this unique Antarctic lake environment.     

The Generation of Superoxide Radicals by Cardiac Mitochondria and the Antioxidant Effect of the Water-Soluble Form of Ubiquinol-10

Biophysics - We have studied the effect of the water-soluble form of ubiquinol-10 (CoQ10-H2) on the processes of electron transport, oxidative phosphorylation, and the formation of reactive oxygen...     

Increased generation of hydroxyl radicals in the rat hypertrophied myocardium: in vivo study by microdialysis

A comparative study of the generation of hydroxyl radicals (OH*) in the hypertrophic myocardium of SHR-SP rats (n = 8) and in the myocardium of WKY (n = 5) and Wistar (n = 12) rats was performed using the microdialysis technique. The experiments were carried out on anesthetized open-chest male rats (ketamine intraperitoneally, 10 mg/kg) with artificial ventilation. The amount of OH* produced was estimated by high-performance liquid chromatography with electrochemical detection using as a marker 2,3-dihydroxybenzoic acid (2,3-DHBA), a product of the reaction of the hydroxyl radical with salicylic acid added to the perfusate. The quantity of 2,3-DHBA in the dialysate was estimated by the external standard method and expressed in percent of the 2,3-DHBA concentration in the perfusion fluid. The mean baseline value of 2,3-DHBA in dialysate samples in SHR-SP rats (157 +/- 22%, n = 8) was significantly higher than in Wistar (90 +/- 15%, n = 12, p = 0.0001) and Wistar-Kyoto rats (106 +/- 12%, n = 5, p = 0.005). The basal 2,3-DHBA level in SHR-SP rats was positively correlated (r = 0.831, n = 7, p < 0.05) with the degree of hypertrophy of the left ventricle expressed as the ratio of the left ventricle weight to the body weight. The data presented demonstrate that the hypertrophy of the left ventricle in SHR-SP rats is accompanied by the elevation of the level of free oxygen radicals.     

Generation of superoxide radicals by heart mitochondria: study by spin trapping under continuous oxygenation

The generation of superoxide radicals by isolated rat heart mitochondria was studied by the spin trapping technique. The sample was placed into the cavity of an EPR spectrometer in a thin-wall teflon capillary tube, which made it possible to maintain the partial oxygen pressure in the mitochondrial suspension at a constant level. Tiron was used as a spin trap, and the intensity of its EPR signal corresponded to the rate of O2-. formation in the sample. The addition of oxidation substrates (succinate, glutamate, and malate) into the incubation mixture caused the appearance of the Tiron EPR signal. The rate of superoxide radical generation by heart mitochondria strongly increased in the presence of antimycin A, an inhibitor of the Q-cycle in complex III of the respiratory chain, but it was completely depressed by another inhibitor of Q-cycle myxothiazol. The inhibition of the reverse electron transport in complex I of the respiratory chain by rotenone (oxidation substrate--succinate) caused a substantial decrease in the rate of O2-. formation by mitochondria.     

Formation of superoxide radicals in isolated cardiac mitochondria: Effect of low oxygen concentration

Formation of superoxide radical in isolated rat heart mitochondria under controlled oxygenation has been studied by spin trapping and EPR oxymetry. Lithium phthalocyanine and perdeuterated Tempone-D-¹⁵ N ₁₆ were used to determine the oxygen concentration. Tiron was used as a spin trap. By varying the oxygen content in the reaction medium, we have shown that isolated heart mitochondria can produce superoxide even at an oxygen partial pressure of 17.5 mmHg, though at a rate considerably lower than under normal conditions. Raising the oxygen concentration increases the rate of superoxide generation.     

Erratum to: Electron Paramagnetic Resonance: Study of the Regulatory Mechanisms of Light Phases of Photosynthesis in Plants

Biophysics - An Erratum to this paper has been published: https://doi.org/10.1134/S0006350922330016