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The frequency of the amantadine-resistant H1N1 influenza A virus has been increasing since the 2005-2006 season. It is unclear whether reassortment was involved in this trend. Here, we show that cocirculation of amantadine-resistant and -sensitive strains led to the genesis of amantadine-sensitive reassortant virus during the 2007-2008 season. Thereafter, the reassortant virus predominated. This contrasts with the trend for the H3N2 virus, in which the amantadine-resistant reassortant virus became predominant. The results suggest that it is necessary to monitor genome dynamics to understand the evolution and mechanism of the emergence and spread of antiviral resistance among influenza A viruses. [ABSTRACT FROM AUTHOR]

The article presents a study which investigates the endocrine disruptive effects of isolated 3-methyl-4-nitrophenol (PNMC) in diesel exhaust particles (DEP) through Hershberger assay in immature rats. It reveals that PNMC has increased the weights of the rats' seminal vesicles and their Cowper's glands, and the concentration of plasma testosterone. In addition, it has reduced the weight of the livers as well as the plasma follicle-stimulating hormone and luteinizing hormone of the subjects.

Tomato (Lycopersiconesculentum) seedlings were grown in the presence of cadmium. After 1 week of Cd treatment, a sharp decline in biomass accumulation in the leaves and roots was observed, together with a decrease in the rate of photosynthetic activity due to both Rubisco and chlorophyll degradation and stomata closure. Cadmium induced a significant decrease in nitrate content and inhibition of the activities of nitrate reductase, nitrite reductase, glutamine synthetase (GS) and ferredoxin-glutamate synthase. An increase in NADH-glutamate synthase and NADH-glutamate dehydrogenase activity was observed in parallel. The accumulation of ammonium into the tissues of treated plants was accompanied by a loss of total protein and the accumulation of amino acids. Gln represented the major amino acid transported through xylem sap of Cd-treated and control plants. Cadmium treatment increased the total amino acid content in the phloem, maintaining Gln/Glu ratios. Western and Northern blot analysis of Cd-treated plants showed a decrease in chloroplastic GS protein and mRNA and an increase in cytosolic GS and glutamate dehydrogenase transcripts and proteins. An increase in asparagine synthetase mRNA was observed in roots, in parallel with a strong increase in asparagine. Taken together, these results suggest that the plant response to Cd stress involved newly induced enzymes dedicated to coordinated leaf nitrogen remobilization and root nitrogen storage. [ABSTRACT FROM AUTHOR]

RalGTPase-activating protein (RalGAP) is an important negative regulator of small GTPases RalA/B that mediates various oncogenic signaling pathways in various cancers. Although the Ral pathway has been implicated in prostate cancer (PCa) development and progression, the significance of RalGAP in PCa has been largely unknown. We examined RalGAPα2 expression using immunohistochemistry on two independent tissue microarray sets. Both datasets demonstrated that the expression of RalGAPα2 was significantly downregulated in PCa tissues compared to adjacent benign prostatic epithelia. Silencing of RalGAPα2 by short hairpin RNA enhanced migration and invasion abilities of benign and malignant prostate epithelial cell lines without affecting cell proliferation. Exogenous expression of wild-type RalGAP, but not the GTPase-activating protein activity-deficient mutant of RalGAP, suppressed migration and invasion of multiple PCa cell lines and was phenocopied by pharmacological inhibition of RalA/B. Loss of Ralgapa2 promoted local microscopic invasion of prostatic intraepithelial neoplasia without affecting tumor growth in a Pten -deficient mouse model for prostate tumorigenesis. Our findings demonstrate the functional significance of RalGAP downregulation to promote invasion ability, which is a property necessary for prostate carcinogenesis. Thus, loss of RalGAP function has a distinct role in promoting progression from prostatic intraepithelial neoplasia to invasive adenocarcinoma. [ABSTRACT FROM AUTHOR]

Ferredoxin:NADP(H) oxidoreductase (FNR) plays a key role in redox metabolism in plastids. Whereas leaf FNR (LFNR) is required for photosynthesis, root FNR (RFNR) is believed to provide electrons to ferredoxin (Fd)- dependent enzymes, including nitrite reductase (NiR) and Fd-glutamine-oxoglutarate aminotransferase (Fd-GOGAT) in non-photosynthetic conditions. In some herbal species, however, most nitrate reductase activity is located in photosynthetic organs, and ammonium in roots is assimilated mainly by Fd-independent NADH-GOGAT. Therefore, RFNR might have a limited impact on N assimilation in roots grown with nitrate or ammonium nitrogen sources. AtRFNR genes are rapidly induced by application of toxic nitrite. Thus, we tested the hypothesis that RFNR could contribute to nitrite reduction in roots by comparing Arabidopsis thaliana seedlings of the wild type with lossof- function mutants of RFNR2. When these seedlings were grown under nitrate, nitrite or ammonium, only nitrite nutrition caused impaired growth and nitrite accumulation in roots of rfnr2. Supplementation of nitrite with nitrate or ammonium as N sources did not restore the root growth in rfnr2. Also, a scavenger for nitric oxide (NO) could not effectively rescue the growth impairment. Thus, nitrite toxicity, rather than N depletion or nitrite-dependent NO production, probably causes the rfnr2 root growth defect. Our results strongly suggest that RFNR2 has a major role in reduction of toxic nitrite in roots. A specific set of genes related to nitrite reduction and the supply of reducing power responded to nitrite concomitantly, suggesting that the products of these genes act co-operatively with RFNR2 to reduce nitrite in roots. [ABSTRACT FROM AUTHOR]

Background Hepcidin is associated with iron-restricted erythropoiesis. A previous cross-sectional study showed that serum hepcidin-25 levels are negatively associated with the hemoglobin concentration in non-dialysis chronic kidney disease (CKD) patients with sufficient iron stores. This longitudinal study aimed at ascertaining the association between hepcidin-25 levels and the progression of renal anemia. Methods We selected 335 non-dialysis CKD patients who showed hemoglobin concentrations >10 g/dL and who were not receiving erythropoiesis-stimulating agent (ESA) therapy, from among the subjects of our previous study, who had been recruited between February and June 2007 in a previous study. The primary outcome was the start of the ESA therapy or hemoglobin concentrations remaining below 10 g/dL for >3 months, by 31 December 2010. The patients were classified into high- and low-ferritin groups depending on their median ferritin levels. The Cox proportional hazard model with restricted cubic spline curve analysis was used to determine the association between hepcidin-25 levels and the outcome for each group. Results The hepcidin-25 level was a significant predictor both for the high-ferritin group (P = 0.04, linearity = 0.02) and for the low-ferritin group (P = 0.04, linearity P = 0.02). The spline curve for the high-ferritin group showed that higher hepcidin-25 levels had a high log-relative hazard. Conclusions Higher hepcidin-25 levels predict the progression of anemia in non-dialysis CKD patients with sufficient iron stores, indicating the involvement of hepcidin in the progression of anemia in non-dialysis CKD patients. [ABSTRACT FROM PUBLISHER]

The article offers information on a study which presents a rapid and specific identification method for the simultaneous detection of mushrooms Omphalotus guepiniformis and Lentinula edodes. It makes use of multiplex real-time polymerase chain reaction (PCR) assay and mentions that the new assay proved specific to the target species. It informs that the assay is highly sensitive and is applicable to processed food samples and gastric juice contents.

Background. Hepcidin is a central regulator of iron homeostasis. Increased hepcidin concentrations could cause iron-restricted erythropoiesis in chronic kidney disease (CKD)-associated anemia. This cross-sectional observational study was conducted to evaluate the association between hepcidin and CKD-associated anemia in non-dialysis CKD patients. Methods. A total of 505 non-dialysis CKD patients not treated with parenteral iron were recruited, and serum hepcidin-25 levels were measured by liquid chromatography tandem mass spectrometry. Multiple linear regression analysis was used to examine the relationship between hepcidin and glomerular filtration rate (GFR) and the relationship between hemoglobin concentration and predictors including the hepcidin level. Results. The median hepcidin level among the 505 CKD patients was 15.4 ng/mL (interquartile range, 5.5–33.6 ng/mL). Although hepcidin level significantly increased according to the CKD stage, multivariate analysis did not reveal an association of GFR with the hepcidin level. Hepcidin level was a significant predictor of hemoglobin concentration after the adjustment for confounders, and a significant interaction between hepcidin and ferritin was found. After stratifying at the median ferritin level, 91 ng/mL, we found a negative association between hepcidin level and hemoglobin in the high-ferritin group. A trend toward a negative association between hepcidin level and mean corpuscular volume was observed in the high-ferritin group. Conclusions. Serum hepcidin-25 levels were negatively associated with hemoglobin concentrations in non-dialysis CKD patients with sufficient iron stores. We found that ferritin modified the association between hepcidin level and hemoglobin concentration. In addition, our results confirmed that the serum hepcidin level is not associated with GFR. [ABSTRACT FROM PUBLISHER]

Background: Productive agriculture needs a large amount of expensive nitrogenous fertilizers. Improving nitrogen use efficiency (NUE) of crop plants is thus of key importance. NUE definitions differ depending on whether plants are cultivated to produce biomass or grain yields. However, for most plant species, NUE mainly depends on how plants extract inorganic nitrogen from the soil, assimilate nitrate and ammonium, and recycle organic nitrogen. Efforts have been made to study the genetic basis as well as the biochemical and enzymatic mechanisms involved in nitrogen uptake, assimilation, and remobilization in crops and model plants. The detection of the limiting factors that could be manipulated to increase NUE is the major goal of such research. [ABSTRACT FROM PUBLISHER]

In higher plants the glutamate dehydrogenase (GDH) enzyme catalyzes the reversible amination of 2-oxoglutarate to form glutamate, using ammonium as a substrate. For a better understanding of the physiological function of GDH either in ammonium assimilation or in the supply of 2-oxoglutarate, we used transgenic tobacco (Nicotiana tabacum L.) plants overexpressing the two genes encoding the enzyme. An in vivo real time 15N-nuclear magnetic resonance (NMR) spectroscopy approach allowed the demonstration that, when the two GDH genes were overexpressed individually or simultaneously, the transgenic plant leaves did not synthesize glutamate in the presence of ammonium when glutamine synthetase (GS) was inhibited. In contrast we confirmed that the primary function of GDH is to deaminate Glu. When the two GDH unlabeled substrates ammonium and Glu were provided simultaneously with either [15N]Glu or 15NH4+ respectively, we found that the ammonium released from the deamination of Glu was reassimilated by the enzyme GS, suggesting the occurrence of a futile cycle recycling both ammonium and Glu. Taken together, these results strongly suggest that the GDH enzyme, in conjunction with NADH-GOGAT, contributes to the control of leaf Glu homeostasis, an amino acid that plays a central signaling and metabolic role at the interface of the carbon and nitrogen assimilatory pathways. Thus, in vivo NMR spectroscopy appears to be an attractive technique to follow the flux of metabolites in both normal and genetically modified plants. [ABSTRACT FROM PUBLISHER]

The present study analyses changes in nitrogen compounds, amino acid composition, and glutamate metabolism in the resurrection plant Sporobolus stapfianus during dehydration stress. Results showed that older leaves (OL) were desiccation-sensitive whereas younger leaves (YL) were desiccation-tolerant. OL lost their soluble protein more rapidly, and to a larger extent than YL. Enzymes of primary nitrogen assimilation were affected by desiccation and the decrease in the glutamine synthetase (GS, EC 6.3.1.2) and ferredoxin-dependent GOGAT (Fd-GOGAT, EC 1.4.7.1) activities was higher in OL than in YL, thus suggesting higher sensibility to dehydration. Moreover, YL showed higher total GS enzyme activity at the end of the dehydration stress and was shown to maintain high chloroplastic GS protein content during the entire stress period. Free amino acid content increased in both YL and OL between 88% and 6% relative water content. Interestingly, OL and YL did not accumulate the same amino acids. OL accumulated large amounts of proline and γ-aminobutyrate whereas YL preferentially accumulated asparagine and arginine. It is concluded (i) that modifications in the nitrogen and amino acid metabolism during dehydration stress were different depending on leaf development and (ii) that proline and γ-aminobutyrate accumulation in S. stapfianus leaves were not essential for the acquisition of desiccation tolerance. On the contrary, the accumulation of large amounts of asparagine and arginine in the YL during dehydration could be important and serve as essential nitrogen and carbon reservoirs useful during rehydration. In this context, the role of GS for asparagine accumulation in YL is discussed. [ABSTRACT FROM PUBLISHER]

Glutamate (Glu) metabolism and amino acid translocation were investigated in the young and old leaves of tobacco (Nicotiana tabacum L. cv Xanthi) using [15N]ammonium and [2-15N]Glu tracers. Regardless of leaf age, [15N]ammonium assimilation occurred via glutamine synthetase (GS; EC 6.1.1.3) and Glu synthase (ferredoxin [Fd]-GOGAT; EC 1.4.7.1; NADH-GOGAT; EC 1.4.1.14), both in the light and darkness, and it did not depend on Glu dehydrogenase (GDH; EC 1.4.1.2). The [15N]ammonium and ammonium accumulation patterns support the role of GDH in the deamination of [2-15N]Glu to provide 2-oxoglutarate and [15N]ammonium. In the dark, excess [15N]ammonium was incorporated into asparagine that served as an additional detoxification molecule. The constant Glu levels in the phloem sap suggested that Glu was continuously synthesized and supplied into the phloem regardless of leaf age. Further study using transgenic tobacco lines, harboring the promoter of the GLU1 gene (encoding Arabidopsis [Arabidopsis thaliana] Fd-GOGAT) fused to a GUS reporter gene, revealed that the expression of Fd-GOGAT remained higher in young leaves compared to old leaves, and higher in the veins compared to the mesophyll. Confocal laser-scanning microscopy localized the Fd-GOGAT protein to the phloem companion cells-sieve element complex in the leaf veins. The results are consistent with a role of Fd-GOGAT in supplying Glu for the synthesis and transport of amino acids. Taken together, the data provide evidence that the GS-GOGAT pathway and GDH play distinct roles in the source-sink nitrogen cycle of tobacco leaves. [ABSTRACT FROM AUTHOR]

In higher plants, ferredoxin (Fd):NADPH oxidoreductase (FNR) catalyzes reduction of NADP+ in the final step of linear photosynthetic electron transport and is also implicated in cyclic electron flow. We have identified three leaf FNR isoenzymes (LFNR1, LFNR2, and LFNR3) in maize (Zea mays) chloroplasts at approximately equivalent concentrations. Fractionation of chloroplasts showed that, while LFNR3 is an exclusively soluble enzyme, LFNR1 is only found at the thylakoid membrane and LFNR2 has a dual location. LFNR1 and LFNR2 were found to associate with the cytochrome b6ƒ complex following its partial purification. We cloned LFNR3 and produced all three isoenzymes as stable, soluble proteins. Measurement of Fd reduction ability showed no significant differences between these recombinant enzymes. Column chromatography revealed variation between the interaction mechanisms of LFNR1 and LFNR2 with Fd, as detected by differential dependence on specific intermolecular salt bridges and variable sensitivity of interactions to changes in pH. A comparison of LFNR transcripts in leaves of plants grown on variable nitrogen regimes revealed that LFNR1 and LFNR2 transcripts are relatively more abundant under conditions of high demand for NADPH. These results are discussed in terms of the functional differentiation of maize LFNR isoenzymes. [ABSTRACT FROM AUTHOR]

The article reports on the results of a study of inter-subspecies hybrid dikaryons of oyster mushroom independently isolated in Vietnam and Japan. A description of the experimental set-up and measurement methods is presented. The study concluded that the asexual reproduction might allow stable maintenance of a particular pair of nuclei.

A correction to the article "Resolving the Role of Plant Glutamate Dehydrogenase. I. In vivo Real Time Nuclear Magnetic Resonance Spectroscopy Experiments" that was published in a previous issue is presented.