In vitro and in vivo effects of iron on the expression and activity of glucose 6‐phosphate dehydrogenase, 6‐phosphogluconate dehydrogenase,and glutathione reductase in rat spleen

Iron is an indispensable element for vital activities in almost all living organisms. It is also a cofactor for many proteins, enzymes, and other essential complex biochemical processes. Therefore, iron trafficking is firmly regulated by Hepcidin (Hamp), which is regarded as the marker for iron accumulation. The disruption of iron homeostasis leads to oxidative stress that causes various human diseases, but this mechanism is still unclear. The aim of this study is to provide a better in vivo and in vitro understanding of how long‐term iron overload affects the gene expression and activities of some antioxidant enzymes, such as glucose 6‐phosphate dehydrogenase (G6PD), 6‐phosphogluconate dehydrogenase (6PGD), and glutathione reductase (GR) in the spleen. The findings of this study show that iron overload reduces the gene expression of G6pd, 6pgd, and Gr, but its actual effect was on the protein level.     

Electrochemical DNA biosensor for detecting cancer biomarker related to glutathione S-transferase P1 (GSTP1) hypermethylation in real samples

An electrochemical genosensor for the detection of hypermethylation of the glutathione S-transferase P1 (GSTP1) gene, a specific marker of prostate cancer, was reported. This new sensor was used in combination with a single-use carbon graphite working electrode and differential pulse voltammetry, with the results of sample analysis based on the guanine oxidation signals obtained at +1.0 V before and after hybridization between probe and synthetic target or denatured PCR samples. The detected DNA hybridization was also characterized by electrochemical impedance spectroscopy with potassium ferri/ferrocyanide as a redox probe. The protocol consisted of 2 different modes: (i) capture probes selective for methylation-specific and unmethylated GSTP1 sequences were immobilized onto the sensor directly, and hybridization was formed on the electrode surface; (ii) probe/target or probe/noncomplementary target couples were mixed in solution phase, and the transducer was modified through simple adsorption. The limit of detection (S/N=3) was calculated as 2.92 pmol of target sequence in a 100-μl reaction volume. The optimum analytical detection parameters for the biosensor, as well as its future prospects, were also presented.     

Electrochemical based detection of microRNA, mir21 in breast cancer cells

Hemagglutinin (HA) is a trimeric glycoprotein expressed on the influenza virus membrane. HA of influenza viruses binds to the host's cell surface complex glycans via a terminal sialic acid (Sia), as the first key step in the process of infection, transmission and virulence of influenza viruses. It is important to monitor and evaluate the receptor (glycan) binding preferences of the HAs derived from influenza A viruses, especially those originating from birds and swine, to understand their potential ability for interspecies transmission. From this viewpoint, in the present study, we have developed a protocol for analyzing the glycan-HA interactions efficiently and kinetically, based on surface plasmon resonance (SPR). Our results showed that glycan-HA binding analyses can be performed reliably and efficiently on Biacore-chips in the SPR system, using chemically synthesized biotinylated multivalent-glycans. Using the CAP-chip, we were able to regenerate the surface for multiple analyses, allowing us to derive, for the first time, the precise kinetic parameters for different HA-glycan complexes of newly emerging influenza viruses. These studies suggested that this SPR-based method is suitable for influenza surveillance to define the pandemic scenario as well as to screen of synthetic glycans and other compounds that may interfere with glycan-HA interactions.     

Clinical course of myelin oligodendrocyte glycoprotein 35-55 induced experimental autoimmune encephalomyelitis is aggravated by glia maturation factor

The role of glia maturation factor (GMF) in myelin oligodendrocyte glycoprotein (MOG) 35-55 peptide-induced experimental autoimmune encephalomyelitis (EAE) was investigated using GMF-deficient (GMF-KO) mice. We demonstrate that GMF-KO mice were resistant to the MOG 35-55 peptide-induced EAE as compared to wild type (Wt) mice (two in eight versus 10 in 10). Next, we examined the effect of administration of recombinant human GMF (rGMF) on MOG 35-55 peptide-induced EAE in mice. Daily administration of rGMF, staring days 1-14, resulted in significant exacerbation of clinical symptoms. Following rGMF injections, both GMF-KO (six in eight) and Wt mice (eight in eight) developed severe EAE (maximal clinical score of 3.5-4.0) with high frequency. The histological examination revealed severe infiltration of inflammatory cells in the spinal cord of MOG-immunized Wt mice while the resistance to EAE in GMF-KO mice was characterized by the absence of inflammatory cells. Administration of rGMF in Wt mice and GMF-KO mice resulted in a significant increase in infiltrating cells in the spinal cord following MOG-immunizations. We also evaluated cytokines and chemokines production as parameters of severity of inflammation in the spinal cord of Wt versus GMF-KO mice with and without GMF-reconstitution following MOG-immunizations. Cytokines (TNF-α, IFN-γ, IL-1β, IL-6) and chemokines (CCL2, CCL3, CXCL10, GM-CSF) production were significantly greater in Wt mice than in GMF-KO mice following MOG-immunization. Furthermore, the reconstitution experiment with rGMF showed that the administration of rGMF in both, Wt mice and GMF-KO mice produced significant increase in the GMF-mediated cytokine/chemokine production.     

Effect of sulfite treatment on total antioxidant capacity, total oxidant status, lipid hydroperoxide, and total free sulfydryl groups contents in normal and sulfite oxidase-deficient rat plasma

Sulfites, which are commonly used as preservatives, are continuously formed in the body during the metabolism of sulfur-containing amino acids. Sulfite oxidase (SOX) is an essential enzyme in the pathway of the oxidative degradation of sulfite to sulfate protecting cells from sulfite toxicity. This article investigated the effect of sulfite on total antioxidant capacity (TAC), total oxidant status, lipid hydroperoxide (LOOH), and total free sulfydryl groups (-SH) levels in normal and SOX-deficient male albino rat plasma. For this purpose, rats were divided into four groups: control, sulfite-treated, SOX-deficient, and sulfite-treated SOX-deficient groups. SOX deficiency was established by feeding rats a low molybdenum diet and adding to their drinking water 200 ppm tungsten. Sulfite (70 mg/kg) was administered to the animals via their drinking water. SOX deficiency together with sulfite treatment caused a significant increase in the plasma LOOH and total oxidant status levels. -SH content of rat plasma significantly decreased by both sulfite treatment and SOX deficiency compared to the control. There was also a significant decrease in plasma TAC level by sulfite treatment. In conclusion, sulfite treatment affects the antioxidant/oxidant balance of the plasma cells of the rats toward oxidants in SOX-deficient groups.     

Serogroup,Virulence, and Genetic Traits of Vibrio parahaemolyticus in the Estuarine Ecosystem of Bangladesh

Forty-two strains of Vibrio parahaemolyticus were isolated from Bay of Bengal estuaries and, with two clinical strains, analyzed for virulence, phenotypic, and molecular traits. Serological analysis indicated O8, O3, O1, and K21 to be the major O and K serogroups, respectively, and O8:K21, O1:KUT, and O3:KUT to be predominant. The K antigen(s) was untypeable, and pandemic serogroup O3:K6 was not detected. The presence of genes toxR and tlh were confirmed by PCR in all but two strains, which also lacked toxR. A total of 18 (41%) strains possessed the virulence gene encoding thermostable direct hemolysin (TDH), and one had the TDH-related hemolysin (trh) gene, but not tdh. Ten (23%) strains exhibited Kanagawa phenomenon that surrogates virulence, of which six, including the two clinical strains, possessed tdh. Of the 18 tdh-positive strains, 17 (94%), including the two clinical strains, had the seromarker O8:K21, one was O9:KUT, and the single trh-positive strain was O1:KUT. None had the group-specific or ORF8 pandemic marker gene. DNA fingerprinting employing pulsed-field gel electrophoresis (PFGE) of SfiI-digested DNA and cluster analysis showed divergence among the strains. Dendrograms constructed using PFGE (SfiI) images from a soft database, including those of pandemic and nonpandemic strains of diverse geographic origin, however, showed that local strains formed a cluster, i.e., “clonal cluster,” as did pandemic strains of diverse origin. The demonstrated prevalence of tdh-positive and diarrheagenic serogroup O8:K21 strains in coastal villages of Bangladesh indicates a significant human health risk for inhabitants.Vibrio parahaemolyticus, a halophilic bacterium, is a causative agent of seafood-related gastroenteritis worldwide (5, 13, 41) and one of the major causes of seafood-associated gastroenteritis in the United States, Asia, Europe, and countries where sporadic cases and outbreaks occur regularly (12, 13). The bacterium is prevalent in brackish and marine waters (43). Historically first identified as the causative agent of a gastroenteritis outbreak in Japan in 1950 (14), V. parahaemolyticus is now recognized as one of the most important food-borne pathogens in Asia, causing approximately half of food poisoning outbreaks in Taiwan, Japan, Vietnam, and Southeast Asian countries.The gene encoding the thermostable direct hemolysin (TDH)—manifested as beta-hemolysis when V. parahaemolyticus is plated onto Wagatsuma blood agar (43), i.e., the Kanagawa phenomenon (KP)—has been shown to be present in more than 90% of clinical strains and less than 1% of environmental strains (31, 39). Some strains also possess the gene trh, encoding the TDH-related hemolysin (TRH), or both tdh and trh (18, 43). Another gene, the thermolabile hemolysin gene (tlh), was reported to be present in V. parahaemolyticus (36) and subsequently in all V. parahaemolyticus strains tested (38).V. parahaemolyticus gastroenteritis is a multiserogroup affliction, with at least 13 O serogroups and 71 K serotypes detected (19, 42). In 1996, serogroup O3:K6 was first reported from diarrhea patients in Kolkata, India (32), and subsequently worldwide, as an increasing incidence of gastroenteritis caused by the serogroup O3:K6 was reported in many countries (41). Rapid spreading of serogroup O3:K6 infections in Asia (27, 32), and subsequently in the United States (12), Africa (3), Europe (25), and Latin America (15), indicated its potential as a pandemic pathogen (34, 43). In addition, V. parahaemolyticus serogroup O3:K6 possesses the group-specific (GS) gene sequence in the toxRS operon and ORF8, of the 10 known open reading frames (ORFs) of the O3:K6-specific filamentous phage f237. The GS gene and ORF8 provide genetic markers distinguishing O3:K6 from other serogroups (27, 29). Recent studies have shown O4:K68, O1:K25, O1:K26, O1:K untypeable (O1:KUT), and O3:K46 serogroups to share genetic markers specific for the pandemic serogroup O3:K6 (7, 10, 27, 34, 41). The non-O3:K6 serogroups with pandemic traits are increasingly found worldwide, and therefore, their pandemic potential cannot be ruled out.In Bangladesh, strains of different serogroups having genetic markers for the serogroup O3:K6 of V. parahaemolyticus were reported to have been isolated from hospitalized gastroenteritis patients in Dhaka (7). A systematic surveillance of the coastal areas bordering the Bay of Bengal where diarrheal disease is endemic (1) has not been done. This study, the first of its kind, was undertaken to investigate virulence potential, as well as phenotypic and genotypic traits of V. parahaemolyticus strains occurring in the estuarine ecosystem of Bangladesh.     

Investigation of glutathione S-transferase M1 and T1 deletions in lung cancer

Glutathione S-transferases (GSTs) M1 and T1 are known to be polymorphic in humans. Both polymorphisms are due to gene deletions which are responsible for the existence of null genotypes. Previous studies have suggested that GST genotypes may play a role in determining susceptibility to a number of unrelated cancers, including lung cancer. The GSTM1 and GSTT1 polymorphisms were determined by PCR-based analysis in 75 lung cancer patients and 55 controls. The unconditional logistic regression analysis was used to calculate ORs and 95% CI. The frequencies of GSTM1 and GSTT1 null genotypes were 37.3 and 22.7% in lung cancer patients and 27.3 and 16.4% in controls, respectively. When analyzed by histology the GSTM1 null genotype was more prevalent in squamous-cell carcinoma and adenocarcinoma patients. Whereas, GSTT1 null genotype frequency was lower in small-cell lung cancer patients than controls. But these differences were not statistically significant. According to smoking status, null genotype for both gene are associated with an increase in risk for lung cancer. Our results suggest that GSTM1 and GSTT1 polymorphisms may play a role in the development of lung cancer for some histological subtypes and modifies the risk of smoking-related lung cancer.     

Testing metabolic ecology theory for allometric scaling of tree size, growth and mortality in tropical forests

The theory of metabolic ecology predicts specific relationships among tree stem diameter, biomass, height, growth and mortality. As demographic rates are important to estimates of carbon fluxes in forests, this theory might offer important insights into the global carbon budget, and deserves careful assessment. We assembled data from 10 old-growth tropical forests encompassing censuses of 367 ha and > 1.7 million trees to test the theory's predictions. We also developed a set of alternative predictions that retained some assumptions of metabolic ecology while also considering how availability of a key limiting resource, light, changes with tree size. Our results show that there are no universal scaling relationships of growth or mortality with size among trees in tropical forests. Observed patterns were consistent with our alternative model in the one site where we had the data necessary to evaluate it, and were inconsistent with the predictions of metabolic ecology in all forests.     

Heavy metal biosorption by biomass of Ochrobactrum anthropi producing exopolysaccharide in activated sludge

The removal of chromium, cadmium and copper, toxic metals of high environmental priority due to their toxicity, from dilute aqueous solutions has been studied in the present work, applying a dead exopolysaccharide producing bacterium, Ochrobactrum anthropi, isolated from activated sludge. Particularly, the effect of pH, metal concentration and the effects of contact time were considered. Optimum adsorption pH values of chromium(VI), cadmium(II) and copper(II) were 2.0, 8.0 and 3.0 respectively. Experimental results also showed the influence of initial metal concentration on the metal uptake for dried biomass. Both the Freundlich and Langmuir adsorption models were suitable for describing the short-term biosorption of chromium(VI), cadmium(II) and copper(II) by O. anthropi.