Purification of glucose 6-phosphate dehydrogenase from chicken erythrocytes. investigation of some kinetic properties

Glucose 6-phosphate dehydrogenase (G6PD) was purified from chicken erythrocytes, and some characteristics of the enzyme were investigated. The purification procedure was composed of three steps: hemolysate preparation, ammonium sulfate precipitation, and 2',5'-ADP Sepharose 4B affinity gel chromatography. Thanks to the three consecutive procedures, the enzyme, having the specific activity of 20.862 EU/mg proteins, was purified with a yield of 54.68% and 9,150-fold. Optimal pH, stable pH, optimal temperature, molecular weight, and KM and Vmax values for NADP+ and glucose 6- phosphate (G6-P) were also determined for the enzyme. In addition, Ki values and the type of inhibition were determined by means of Line-Weaver-Burk graphs obtained for such inhibitors as ATP, ADP, NADH, and NADPH.     

Zinc efficiency is correlated with enhanced expression and activity of zinc-requiring enzymes in wheat

Zinc (Zn) is an essential micronutrient for plants. The ability of plants to maintain significant yields under low Zn is termed Zn efficiency (ZE) and its genetic and mechanistic basis is still not well understood. Previously, we showed that root Zn uptake did not play a role in ZE. In the current study, Zn-efficient and -inefficient wheat (Triticum aestivum) genotypes were grown for 13 d in chelate buffer nutrient solutions at low (0.1 pM), sufficient (150 pM), and high (1 microM) Zn(2+) activities and analyzed for root-to-shoot translocation of Zn, subcellular leaf Zn distribution, and activity and expression of the Zn-requiring enzymes in leaves. No correlation between ZE and Zn translocation to the shoot was found. Furthermore, total and water-soluble concentrations of leaf Zn were not associated with ZE, and no differences in subcellular Zn compartmentation were found between Zn-efficient and -inefficient genotypes. However, the expression and activity of the Zn-requiring enzymes copper (Cu)/Zn superoxide dismutase (SOD) and carbonic anhydrase did correlate with differences in ZE. Northern analysis suggested that Cu/ZnSOD gene expression was up-regulated in the Zn-efficient genotype, Kirgiz, but not in inefficient BDME. Under Zn deficiency stress, the very Zn-efficient genotype Kirgiz and moderately Zn-efficient Dagdas exhibited an increased activity of Cu/ZnSOD and carbonic anhydrase when compared with Zn-inefficient BDME. These results suggest that Zn-efficient genotypes may be able to maintain the functioning of Zn-requiring enzymes under low Zn conditions; thus, biochemical Zn utilization may be an important component of ZE in wheat.     

Effects of lactulose and lactitol on coliform bacteria and bacterial translocation in the caecum during 72-h starvation in rats

Lactulose and lactitol, non-absorbable disaccharides, prevent bacterial translocation (BT) arising from the gut. In contrast, lack of food into the gut leads to coliform bacterial overgrowth and even if it does not cause BT, can induce the risk from other stimuli for BT. In this study, we tested whether lactulose and lactitol affected populations of coliform bacteria in the caecum during starvation in Sprague-Dawley rats. Three groups of rats were starved for 72 h and given oral 2 ml undiluted lactulose (670 mg/ml), 2 ml undiluted lactitol (666 mg/ml) or 2 ml physiological saline, respectively, once a day. The caecum and mesenteric lymph nodes (MLNs) were removed for microbiological and histopathological analyses. The highest degree of coliform bacterial overgrowth, BT to MLNs and histopathological damage were observed in lactulose-treated rats, followed by the group treated with lactitol. As a result of this study, both drugs, especially lactulose augmented the proliferation and translocation tendency of coliform bacteria in the caecum during 72-h starvation in rats.     

Teaching embryology to undergraduates in the Faculty of Education at Dokuz Eylul University in Izmir,Turkey

This report reviews the way in which classical embryology is taught and interpreted at the Buca Faculty of Education, in Dokuz Eylul University (Turkey). This university is one of the leading teacher-education institutions in Turkey. My course is taught with appreciation of the fact that students are thinking ideologically rather than scientifically with regard to creationism and evolution in both cognitive and educational processes. However, this ideological orientation, along with lack of classroom time and material resources, hinders my goal of a student-centered education. Being flexible with regard to philosophical and metaphysical issues on which concepts of evolution and creationism are in conflict, is constructive for student development and represents the approach I endeavor to pursue.     

Whole body exposure of rats to microwaves emitted from a cell phone does not affect the testes

The objective of this study was to investigate the effects of radiofrequency radiation emitted from cellular phones on the lipid composition, malondialdehyde concentration, p53 immune reactivity, sperm count, morphology, histological structure of testes, and on rectal temperature of rats exposed to microwave radiation emitted from cellular phones. Sixteen Spraque-Dawley rats were separated into two groups of eight, sham exposed (control) and experimental. The rats were confined in plexiglas cages specially designed for this study, and cellular phones were placed 0.5 cm under the cages. For the experimental group, cellular phones were activated 20 min per day (7 days a week) for 1 month. For the control group, the cellular phones were placed beneath the cages for 20 min a day, but the phones were turned off. Rectal temperatures were measured weekly. For 250 mW radiated power, the whole body average SAR (rms) is 0.52 W/kg and 1 g averaged peak SAR (rms) is 3.13 W/kg. The Mann-Whitney U-test was used for statistical comparisons of groups. No statistically significant alteration in any of the endpoints was noted. This study found no evidence suggesting an adverse effect of cell phone exposure on measures of testicular function or structure.     

Histological and biochemical effects of cigarette smoke on lungs

In this study, rats were made to inhale cigarette smoke in a specifically prepared container for different periods. The lung tissue samples of the subjects were examined by light microscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Malonaldehyde, one of the free oxygen radicals was determined in lungs and plasma. The catalase activity level of erythrocyte and arginase levels were determined. Three groups were formed. The rats in the Ist and IInd groups were made to inhale cigarette smoke for 30 and 60 minutes a day for a total period of 3 months. Control group, the rats in the IIIrd group (controls) were made to inhale clean air during the same periods. An increase in the number of macrophages was observed in the pulmonary tissue of the exposed groups. Especially in the group that inhaled the smoke for long periods, the number of macrophages and the inclusion bodies contained in them increased. These differences could easily be observed in TEM studies. In the light microscopy and SEM observations, it arouse attention that the alveolar macrophages occurred as sets and their activation increased. Depending on the length of the exposure to cigarette smoke, an increase in the number of macrophages was observed. Statistically significant increases were determined in the malonaldehyde levels of pulmonary tissue and plasma when compared to the control group. Besides significant increases were found in the catalase activity levels of erythrocytes in the experimental groups.     

Antimicrobial and biological effects of ipemphos and amphos on bacterial and yeast strains

In this study, the antimicrobial effects of monophosphazenes such as SM ipemphos and amphos were examined on bacterial and yeast strains. In addition, the biological effects of these compounds were tested on the lipid level of Saccharomyces cerevisiae and Candida albicans cells. The SM has an antimicrobial effect on the bacterial and yeast strains within the range of 100 and 1500 microg. When the concentration was increased, the inhibition zone expanded on the growth media ( p < 0.01; p < 0.001). The ipemphos did not affect the bacterial and yeast cells in the 100 and 600 microg range. In addition, the amphos did not show an antimicrobial effect on the bacterial cells between 100 and 300 microg or on yeast cells at any of the administered concentrations. In vitro media, the biological effects of these molecules were compared with vitamin E, melatonin and fish oil on the yeast cells. We have found that monophosphazenes have growth effects on the cells in vitro media. The lipid level of S. cerevisiae cells was decreased by 300 microg doses of vitamin E, fish oil, and ipemphos (respectively; p < 0.05, p < 0.01, and p < 0. 001). In addition, the lipid levels of the same yeast cells were depressed by 1000-microg doses in all supplemented groups. However, it was observed that the highest decrease in lipid level of S. cerevisiae cells occurred in the amphos group ( p < 0.001). The lipid levels of the C. albicans cells were significantly reduced ( p < 0.01) by 300 microg of amphos and melatonin. In contrast, the vitamin E and fish oil significantly raised ( p < 0.01; p < 0.001) the lipid level of the same yeast cell, as compared with the control. In addition, the lipid level of these cells was increased by administration of 1000 microg vitamin E, and melatonin ( p < 0.01). In conclusion, while high concentrations of ipemphos and amphos have an antimicrobial effect on bacterial and yeast cells, amphos did not affect the yeast cells. While ipemphos and amphos increased cell growth in media, they reduced the lipid level of C. albicans and S. cerevisiae. In addition, the antioxidants such as vitamin E, melatonin, and fish oils affected the lipid level of yeast cells.     

Influence of varied zinc supply on re-translocation of cadmium (109Cd) and rubidium (86Rb) applied on mature leaf of durum wheat seedlings

Effect of varied zinc (Zn) supply (0, 0.1, 1, 5 M) on re-translocation of radio-labeled cadmium (¹⁰⁹Cd) and rubidium (⁸⁶Rb) from mature leaf to root and other parts of shoot was studied in 11-day-old durum wheat (Triticum durum cv. C-1252) plants grown in nutrient solution under controlled environmental conditions. Application of ¹⁰⁹Cd and ⁸⁶Rb was carried out by immersing the tips (3 cm) of mature leaf in radio-labeled solutions for 10 s at three different times over a 42 h period. Differences in Zn supply for 11 days did not affect plant growth nor did it cause visual leaf symptoms, such as necrosis and chlorosis, at either the lowest or the highest Zn supply. Only at the nil Zn supply (0 M), shoot and root dry weights tended to decrease and increase, respectively, causing a lower shoot/root dry weight ratio. Partitioning of more dry matter to roots rather than shoots, a typical phenomena for Zn-deficient plants in nutrient solution experiments, indicated existence of a mild Zn deficiency stress at the nil-Zn treatment. Irrespective of Zn supply, plants could, on average, retranslocate 3.8% and 38% of the total absorbed ¹⁰⁹Cd and ⁸⁶Rb from the treated leaf to roots and other parts of shoots within 42 h, respectively. At nil-Zn treatment, 2.8% of the total absorbed ¹⁰⁹Cd was re-translocated from the treated leaf, particularly into roots. The highest re-translocation of ¹⁰⁹Cd (6.5%) was found in plants supplied with 0.1 M Zn. Increases in Zn supply from 0.1 M reduced ¹⁰⁹Cd re-translocation from 6.5% to 4.3% at 1 M Zn and 1.3% at 5 M Zn. With the exception of the nil-Zn treatment, the proportion of re-translocated ¹⁰⁹Cd was greater in the remainder of the shoot than in the roots. Contrary to the ¹⁰⁹Cd results, re-translocation of ⁸⁶Rb was not (at 0, 0.1 and 1 M Zn), or only slightly (at 5 M), affected by changing Zn supply. The results indicate an inhibitory action of increased concentrations of Zn in shoot tissues on phloem-mediated Cd transport. This effect is discussed in relation to competitive inhibition of Cd loading into phloem sap by Zn.     

PRMT1 promotes the tumor suppressor function of p14ARF and is indicative for pancreatic cancer prognosis

The p14^ARF protein is a well‐known regulator of p53‐dependent and p53‐independent tumor‐suppressive activities. In unstressed cells, p14^ARF is predominantly sequestered in the nucleoli, bound to its nucleolar interaction partner NPM. Upon genotoxic stress, p14^ARF undergoes an immediate redistribution to the nucleo‐ and cytoplasm, where it promotes activation of cell cycle arrest and apoptosis. Here, we identify p14^ARF as a novel interaction partner and substrate of PRMT1 (protein arginine methyltransferase 1). PRMT1 methylates several arginine residues in the C‐terminal nuclear/nucleolar localization sequence (NLS/NoLS) of p14^ARF. In the absence of cellular stress, these arginines are crucial for nucleolar localization of p14^ARF. Genotoxic stress causes augmented interaction between PRMT1 and p14^ARF, accompanied by arginine methylation of p14^ARF. PRMT1‐dependent NLS/NoLS methylation promotes the release of p14^ARF from NPM and nucleolar sequestration, subsequently leading to p53‐independent apoptosis. This PRMT1‐p14^ARF cooperation is cancer‐relevant and indicative for PDAC (pancreatic ductal adenocarcinoma) prognosis and chemotherapy response of pancreatic tumor cells. Our data reveal that PRMT1‐mediated arginine methylation is an important trigger for p14^ARF’s stress‐induced tumor‐suppressive function.