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Iron overload caused by hereditary hemochromatosis (HH) increases free reactive oxygen species that, in turn, induce lipid peroxidation. Its 4-hydroxynonenal (HNE) by-product is a well-established marker of lipid peroxidation since it reacts with accessible proteins with deleterious consequences. Indeed, elevated levels of HNE are often detected in a wide variety of human diseases related to oxidative stress. Here, we evaluated HNE-modified proteins in the membrane of erythrocytes from HH patients and in organs of Hfe−/− male and female mice, a mouse model of HH. For this purpose, we used one- and two-dimensional gel electrophoresis, immunoblotting and MALDI-TOF/TOF analysis. We identified cytoskeletal membrane proteins and membrane receptors of erythrocytes bound to HNE exclusively in HH patients. Furthermore, kidney and brain of Hfe−/− mice contained more HNE-adducted protein than healthy controls. Our results identified main HNE-modified proteins suggesting that HH favours preferred protein targets for oxidation by HNE.

Assessment of serological Plasmodium falciparum–specific antibodies in highly endemic areas provides valuable information about malaria status and parasite exposure in the population. Although serological evidence of Plasmodium exposure is commonly determined by Plasmodium-specific immunoglobulin G (IgG) levels; IgM and IgA are likely markers of malaria status that remain relatively unexplored. Previous studies on IgM and IgA responses have been based on their affinity for single antigens with shortage of immune responses analysis against the whole Plasmodium proteome. Here, we provide evidence of how P. falciparum infection triggers the production of specific IgM and IgA in plasma and its relationship with parasite density and changes in hematological parameters. A total of 201 individuals attending a hospital in Breman Asikuma, Ghana, were recruited into this study. Total and P. falciparum–specific IgM, IgA, and IgG were assessed by ELISA and examined in relation to age (0–5, 14–49, and ≥50 age ranges); infection (submicroscopic vs. microscopic malaria); pregnancy and hematological parameters. Well-known IgG response was used as baseline control. P. falciparum–specific IgM and IgA levels increased in the population with the age, similarly to IgG. These data confirm that acquired humoral immunity develops by repeated infections through the years endorsing IgM and IgA as exposure markers in endemic malaria regions. High levels of specific IgA and IgM in children were associated with microscopic malaria and worse prognosis, because most of them showed severe anemia. This new finding shows that IgM and IgA may be used as diagnostic markers in this age group. We also found an extremely high prevalence of submicroscopic malaria (46.27% on average) accompanied by IgM and IgA levels indistinguishable from those of uninfected individuals. These data, together with the observed lack of sensitivity of rapid diagnostic tests (RDTs) compared to PCR, invoke the urgent need to implement diagnostic markers for submicroscopic malaria. Overall, this study opens the potential use of P. falciparum–specific IgM and IgA as new serological markers to predict malaria status in children and parasite exposure in endemic populations. The difficulties in finding markers of submicroscopic malaria are highlighted, emphasizing the need to explore this field in depth.

Assessment of serological

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Incomplete non-sterile immunity to malaria is attained in endemic regions after recurrent infections by a large percentage of the adult population, who carry the malaria parasite asymptomatically. Although blood-stagePlasmodium falciparumrapidly elicits IgG responses, the target antigens of partially protective and non-protective IgG antibodies as well as the basis for the acquisition of these antibodies remain largely unknown. We performed IgG-immunomics to screen forP. falciparumantigens and to identify epitopes associated with exposure and clinical disease. Sera from malaria cases identified five prevalent antigens recognized by all analyzed patients’ IgGs. For further epitope mapping, peptide microarrays designed to cover their sequences were probed with a set of 38 sera samples from adult individuals of an endemic malaria region in Ghana. Eight 20-mer peptides with the highest affinity and frequency of recognition among the population were subsequently validated with 16 sera from the same region, segregated into patients with positive or negative subclinical detection ofP. falciparum. Significant binding specificity for two immunodominant antigenic regions was uncovered within the START-related lipid transfer protein and the protein disulfide isomerase PDI8. These 20-mer peptides challenged with sera samples from children under 5 years old displayed specific IgG binding in those with detectable parasitemia, even at subclinical level. These results suggest that the humoral response against START and PDI8 antigens may be triggered even at submicroscopic parasitemia levels in children and may eventually be used to differentially diagnose subclinical malaria in children.SignificanceMalaria in Africa is a leading cause of morbidity and mortality. The reservoirs of the malaria parasite are asymptomatic patients who carry it subclinically. Identifying the parasite antigens and its fragments that trigger the most common immunity response by immunoglobulin G that partially protect people can have profound implications for both, development of a malaria vaccine and diagnosis of the subclinical parasite carriers. Antigen discovery and mapping, validated with sera from subclinical carriers, showed that immunoglobulin G responses in children against parasite’s START and PDI8 may eventually be used to differentially diagnose non-infected from subclinical cases. Furthermore, anti-START and anti-PDI8 endemic immunodominance provides association of these antigens with long-term acquired immunity and immune evasion to malaria.

Background:Recent advances in antiviral therapy show potential for a cure and/or control of most human infections caused by hepatitis viruses and retroviruses. However, medical success is largely dependent on the identification of the large number of people unaware of these infections, especially in developing countries. Dried blood spots (DBS) have been demonstrated to be a good tool for collecting, storing and transporting clinical specimens from rural areas and limited-resource settings to laboratory facilities, where viral infections can be more reliably diagnosed.Methods:The seroprevalence and virological characterization of hepatitis B virus (HBV) and hepatitis C virus (HCV), as well as human retroviruses (HIV-1, HIV-2, human T-cell leukaemia virus type 1 [HTLV-1] and human T-cell leukaemia virus type 2 [HTLV-2]), were investigated in clinical specimens collected from DBS in Ghana.Results:A total of 305 consecutive DBS were collected. A high prevalence of chronic HBV (8.5%) and occult hepatitis B (14.2%) was found, whereas rates were lower for HIV-1, HTLV-1 and HCV (3.2%, 1.3% and 0.6%, respectively). HIV-2 and HTLV-2 were absent. CRF02_AG was the predominant HIV-1 subtype, whereas genotype E was the most frequent HBV variant.Conclusions:DBS are helpful in the diagnosis and virological characterization of hepatitis and retrovirus infections in resource-limited settings. The high rate of hepatitis B in Ghana, either overt or occult, is noteworthy and confirms recent findings from other sub-Saharan countries. This should encourage close clinical follow up and antiviral treatment assessment in this population, as well as universal HBV vaccine campaigns.

The co-endemicity of malnutrition, erythrocytopathies, transmissible diseases and iron-deficiency contribute to the prevalence of chronic anaemia in many populations of the developing world. Although iron dietary supplementation is applied or recommended in at risk populations, its use is controversial due to undesirable outcomes, particularly regarding the response to infections, including highly prevalent malaria. We hypothesized that a boosted oxidative stress due to iron supplementation have a similar impact on malaria to that of hereditary anaemias, enhancing innate response and conditioning tissues to prevent damage during infection. Thus, we have analysed antioxidant and innate responses against lethal Plasmodium yoelii during the first five days of infection in an iron-supplemented mouse. This murine model showed high iron concentration in plasma with upregulated expression of hemoxygenase-1. The sustained homeostasis after this extrinsic iron conditioning, delayed parasitemia growth that, once installed, developed without anaemia. This protection was not conferred by the intrinsic iron overload of hereditary hemochromatosis. Upon iron-supplementation, a large increase of the macrophages/dendritic cells ratio and the antigen presenting cells was observed in the mouse spleen, independently of malaria infection. Complementary, malaria promoted the splenic B and T CD4 cells activation. Our results show that the iron supplementation in mice prepares host tissues for oxidative-stress and induces unspecific cellular immune responses, which could be seen as an advantage to promote early defences against malaria infection.

Proteomics is improving malaria research by providing global information on relevant protein sets from the parasite and the host in connection with its cellular structures and specific functions. In the last decade, reports have described biologically significant elements in the proteome of Plasmodium, which are selectively targeted and quantified, allowing for sensitive and high-throughput comparisons. The identification of molecules by which the parasite and the host react during the malaria infection is crucial to the understanding of the underlying pathogenic mechanisms. Hence, proteomics is playing a major role by defining the elements within the pathogenic space between both organisms that change across the parasite life cycle in association with the host transformation and response. Proteomics has identified post-translational modifications in the parasite and the host that are discussed in terms of functional interactions in malaria parasitism. Furthermore, the contribution of proteomics to the investigation of immunogens for potential vaccine candidates is summarized. The malaria-specific technological advances in proteomics are particularly suited now for identifying host-parasite interactions that could lead to promising targets for therapy, diagnosis or prevention. In this review, we examine the knowledge gained on the biology, pathogenesis, immunity and diagnosis of Plasmodium infection from recent proteomic studies. This article is part of a Special Issue entitled: Trends in Microbial Proteomics.

Oxidative stress has been attributed both a key pathogenic and rescuing role in cerebral malaria (CM). In a Plasmodium berghei ANKA murine model of CM, host redox signaling and functioning were examined during the course of neurological damage. Host antioxidant defenses were early altered at the transcriptional level indicated by the gradually diminished expression of superoxide dismutase-1 (sod-1), sod-2, sod-3 and catalase genes. During severe disease, this led to the dysfunctional activity of superoxide dismutase and catalase enzymes in damaged brain regions. Vitagene associated markers (heat shock protein 70 and thioredoxin-1) also showed a decaying expression pattern that paralleled reduced expression of the transcription factors Parkinson disease 7, Forkhead box O 3 and X-box binding protein 1 with a role in preserving brain redox status. However, the oxidative stress markers reactive oxygen/nitrogen species were not accumulated in the brains of CM mice and redox proteomics and immunohistochemistry failed to detect quantitative or qualitative differences in protein carbonylation. Thus, the loss of antioxidant capacity was compensated for in all cerebral regions by progressive upregulation of heme oxygenase-1, and in specific regions by early glutathione peroxidase-1 induction. This study shows for the first time a scenario of cooperative glutathione peroxidase and heme oxygenase-1 upregulation to suppress superoxide dismutase, catalase, heat shock protein-70 and thioredoxin-1 downregulation effects in experimental CM, counteracting oxidative damage and maintaining redox equilibrium. Our findings reconcile the apparent inconsistency between the lack of oxidative metabolite build up and reported protective effect of antioxidant therapy against CM.

Background and Purpose Blood-stage Plasmodium parasites cause morbidity and mortality from malaria. Parasite resistance to drugs makes development of new chemotherapies an urgency. Aminoacyl-tRNA synthetases have been validated as antimalarial drug targets. We explored long-term effects of borrelidin and mupirocin in lethal P. yoelii murine malaria. Experimental Approach Long-term (up to 340 days) immunological responses to borrelidin or mupirocin were measured after an initial 4 day suppressive test. Prophylaxis and cure were evaluated and the inhibitory effect on the parasites analysed. Key Results Borrelidin protected against lethal malaria at 0.25 mg·kg−1·day−1. Antimalarial activity of borrelidin correlated with accumulation of trophozoites in peripheral blood. All infected mice treated with borrelidin survived and subsequently developed immunity protecting them from re-infection on further challenges, 75 and 340 days after the initial infection. This long-term immunity in borrelidin-treated mice resulted in negligible parasitaemia after re-infections and marked increases in total serum levels of antiparasite IgGs with augmented avidity. Long-term memory IgGs mainly reacted against high and low molecular weight parasite antigens. Immunofluorescence microscopy showed that circulating IgGs bound predominantly to late intracellular stage parasites, mainly schizonts. Conclusions and Implications Low borrelidin doses protected mice from lethal malaria infections and induced protective immune responses after treatment. Development of combination therapies with borrelidin and selective modifications of the borrelidin molecule to specifically inhibit plasmodial threonyl tRNA synthetase should improve therapeutic strategies for malaria.

The molecular basis for the prevalence of blood group O in regions where malaria is endemic remains unclear. In some genetic backgrounds oxidative modifications have been linked to a reduced susceptibility to severe malaria disease. Through redox proteomics, we detected differences in carbonylated membrane proteins among the different blood groups, both in Plasmodium-infected and uninfected erythrocytes (RBC). Carbonylation profiles of RBC membrane proteins revealed that group O blood shows a reduced protein oxidation pattern compared to groups A, B and AB. Upon infection with Plasmodium falciparum Dd2, erythrocytes of all blood groups showed increased oxidation of membrane proteins. By examining 4-hydroxy-2-nonenal (4-HNE) modified proteins by LC-MS/MS (liquid chromatography/mass spectrometry) we observed that, upon malaria infection, the protein components of lipid rafts and cytoskeleton were the main targets of 4-HNE carbonylation in all blood groups. Ankyrins and protein bands 4.2 and 4.1 were differentially carbonylated in group O as compared to A and B groups. During trophozoite maturation in group O erythrocytes, a steady increase was observed in the number of 4-HNE-modified proteins, suggesting a parasite-driven 4-HNE-carbonylation process. Our findings indicate a possible correlation between the protection against severe malaria in blood group O individuals and a specific pattern of 4-HNE-carbonylation of cytoskeleton proteins.

As the search for an effective human malaria vaccine continues, understanding immune responses to Plasmodium in rodent models is perhaps the key to unlocking new vaccine strategies. The recruitment of parasite-specific antibodies is an important component of natural immunity against infection in blood-stage malaria. Here, we describe the use of sera from naturally surviving ICR mice after infection with lethal doses of Plasmodium yoelii yoelii 17XL to identify highly immunogenic blood-stage antigens. Immobilized protein A/G was used for the affinity-chromatography purification of the IgGs present in pooled sera from surviving mice. These protective IgGs, covalently immobilized on agarose columns, were then used to isolate reactive antigens from whole P. yoelii yoelii 17XL protein extracts obtained from the blood-stage malaria infection. Through proteomics analysis of the recovered parasite antigens, we were able to identify two endoplasmic reticulum lumen proteins: protein disulfide isomerase and a member of the heat shock protein 70 family. Also identified were the digestive protease plasmepsin and the 39 kDa-subunit of eukaryotic translation initiation factor 3, a ribosome associated protein. Of these four proteins, three have not been previously identified as antigenic during blood-stage malaria infection. This procedure of isolating and identifying parasite antigens using serum IgGs from malaria-protected individuals could be a novel strategy for the development of multi-antigen-based vaccine therapies. 2.814 JCR (2012) Q3, 70/137 Immunology

Most drugs against malaria that are available or under development target a single process of the parasite infective cycle, favouring the appearance of resistant mutants which are easily spread in areas under chemotherapeutic treatments. Maslinic acid (MA) is a low toxic natural pentacyclic triterpene for which a wide variety of biological and therapeutic activities have been reported. Previous work revealed that Plasmodium falciparum erythrocytic cultures were inhibited by MA, which was able to hinder the maturation from ring to schizont stage and, as a consequence, prevent the release of merozoites and the subsequent invasion. We show here that MA effectively inhibits the proteolytic processing of the merozoite surface protein complex, probably by inhibition of PfSUB1. In addition, MA was also found to inhibit metalloproteases of the M16 family by a non-chelating mechanism, suggesting the possible hindrance of plasmodial metalloproteases belonging to that family, such as falcilysin and apicoplast peptide-processing proteases. Finally, in silico target screening was used to search for other potential binding targets that may have remained undetected. Among the targets identified, the method recovered two for which experimental activity could be confirmed, and suggested several putative new targets to which MA could have affinity. One of these unreported targets, phospholipase A2, was shown to be partially inhibited by MA. These results suggest that MA may behave as a multi-targeted drug against the intra-erythrocytic cycle of Plasmodium, providing a new tool to investigate the synergistic effect of inhibiting several unrelated processes with a single compound, a new concept in antimalarial research.

Resistance to chloroquine (CQ) in Plasmodium falciparum has a major impact on malaria control worldwide. To gain insight into early parasite stress response, mRNA expression profiles were determined for a set of 10 antioxidant defence genes in synchronized CQ-sensitive (3D7) and CQ-resistant (Dd2) clones under transient IC50 CQ-exposure (Dd2, 200 nM; 3D7, 14 nM). Upon 2-h CQ challenge, the mRNA upregulation detected was greater in 3D7 (six genes overexpressed at 1/3 of the intraerythrocytic cycle) than in Dd2 clone (three genes responding), providing evidence of an early transcriptional response to CQ-induced oxidative stress which might underlie some of the parasite's metabolic adaptation to the drug.

In cerebral malaria, the most severe complication of malaria, both neurotransmission mechanisms and energy metabolism are affected. To understand how metabolic changes modify neurotransmission, we examined P2 receptor expression in a murine model of cerebral malaria. Quantitative polymerase chain reaction experiments revealed that parasite deposition was greatest in the cerebellum, compared with other areas of the brain, suggesting a correlation between brain parasitemia and loss of control of movement. Infected mice showed modified patterns of expression of P2 receptor subtype messenger RNA (mRNA), depending on both the specific purinergic receptor and the cerebral region analyzed. Immunohistochemical studies indicated altered levels of protein expression by these receptors in infected brains and, in some cases, a pattern of expression different from that noted in control mice. These differences in both the amount of mRNA and the protein distribution of P2 receptors observed in the different brain sites in infected mice suggest an important role for P2 receptors in either provoking cerebral damage or conferring neuroprotection.

Resistance of Plasmodium falciparum to chloroquine hinders malaria control in endemic areas. Current hypotheses on the action mechanism of chloroquine evoke its ultimate interference with the parasite's oxidative defence systems. Through carbonyl derivatization by 2,4-dinitrophenylhydrazine and proteomics, we compared oxidatively modified proteins across the parasite's intraerythrocytic stages in untreated and transiently IC 50 chloroquine-treated cultures of the chloroquine-resistant P. falciparum strain Dd2. Functional plasmodial protein groups found to be most oxidatively damaged were among those central to the parasite's physiological processes, including protein folding, proteolysis, energy metabolism, signal transduction, and pathogenesis. While an almost constant number of oxidized proteins was detected across the P. falciparum life cycle, chloroquine treatment led to increases in both the extent of protein oxidation and the number of proteins oxidized as the intraerythrocytic cycle progressed to mature stages. Our data provide new insights into early molecular effects produced by chloroquine in the parasite, as well as into the normal protein-oxidation modifications along the parasite cycle. Oxidized proteins involved in the particular parasite drug-response suggest that chloroquine causes specific oxidative stress, sharing common features with eukaryotic cells. Targeting these processes might provide ways of combating chloroquine-resistance and developing new antimalarial drugs.

This report describes a set of 21 polymerase chain reaction primers and amplification conditions developed to barcode practically any teleost fish species according to their mitochondrial cytochrome b and nuclear rhodopsin gene sequences. The method was successfully tested in more than 200 marine fish species comprising the main Actinopterygii family groups. When used in phylogenetic analyses, its combination of two genes with different evolutionary rates serves to identify fish at the species level. We provide a flow diagram indicating our validated polymerase chain reaction amplification conditions for barcoding and species identification applications as well as population structure or haplotyping analyses, adaptable to high-throughput analyses.

To maximize growth, farmed fish are fed high-fat diets, which can lead to high tissue lipid concentrations that have an impact on quality. The intake of conjugated linoleic acid (CLA) reduces body fat in mammals and this study was undertaken to determine the effects of dietary CLA on growth, composition, and postprandial metabolic variables in sea bream. Fish were fed 3 diets containing 48 g/100 g protein and 24 g/100 g fat, including fish oil supplemented with 0 (control), 2, or 4% CLA for 12 wk. Feed intake, specific growth rate, total body fat, and circulating somatolactin concentration were lower in fish fed CLA than in controls. Feed efficiency was greater in fish fed 2% CLA than in controls. Liver triglyceride concentrations were higher in fish fed 4% CLA and muscle triglyceride concentrations were lower in fish fed both CLA diets than in controls. Hepatic fatty acyl desaturase and elongase mRNA levels in fish fed CLA were lower than in controls. Metabolic differences between controls and CLA-fed fish were observed at 6 h but not at 24 h after the last meal, including lower postprandial circulating triglyceride concentrations, higher hepatic acyl-CoA-oxidase, and lower L-3-hydroxyacyl-CoA dehydrogenase activities in CLA-fed fish than in controls. Dietary CLA did not affect enzymes involved in lipogenesis including hepatic fatty acid synthase and malic enzyme, but it decreased glucose 6-phosphate dehydrogenase activity at 24 h, but not at 6 h after feeding. The data suggest that CLA intake in sea bream has little effect on hepatic lipogenesis, channels dietary lipid from adipose tissue to the liver, and switches hepatic mitochondrial to peroxisomal beta-oxidation.

Human pyruvate kinase deficiency (PKD), an autosomal recessive disorder produced by mutations in the PKLR gene, is the most common cause of chronic nonspherocytic hemolytic anemia. Transduction of wild-type erythroid (R-type) pyruvate kinase (RPK) cDNA into deficient hematopoietic stem cells could be of potential use as rescue therapy in severe clinical cases. In this study, gammaretroviral vectors expressing human RPK were designed as possible gene therapy candidates for this disease. Through real-time quantitative reverse transcriptase-polymerase chain reaction, Western blotting, and flow cytometric analysis, we demonstrate stable RPK expression in both undifferentiated and differentiated murine erythroleukemia cells. In this in vitro assay, the proportion of transduced cells and the intensity of expression of the transgene remained unaltered after 6 months of culture. Moreover, transplanting human RPK-transduced Lin(-)Sca-1(+) mouse cells in myeloablated primary and secondary recipients rendered high proportions of erythroid precursors and mature erythrocytes expressing RPK, without inducing hematopoietic effects. These findings suggest that retroviral vectors could be useful for the delivery and expression of RPK in erythroid cells, and provide evidence of the potential use of gene therapy strategies to phenotypically correct erythroid PKD.

Nna1 has some sequence similarity to metallocarboxypeptidases, but the biochemical characterization of Nna1 has not previously been reported. In this work we performed a detailed genomic scan and found >100 Nna1 homologues in bacteria, Protista, and Animalia, including several paralogs in most eukaryotic species. Phylogenetic analysis of the Nna1-like sequences demonstrates a major divergence between Nna1-like peptidases and the previously known metallocarboxypeptidases subfamilies: M14A, M14B, and M14C. Conformational modeling of representative Nna1-like proteins from a variety of species indicates an unusually open active site, a property that might facilitate its action on a wide variety of peptide and protein substrates. To test this, we expressed a recombinant form of one of the Nna1-like peptidases from Caenorhabditis elegans and demonstrated that this protein is a fully functional metallocarboxypeptidase that cleaves a range of C-terminal amino acids from synthetic peptides. The enzymatic activity is activated by ATP/ADP and salt-inactivated, and is preferentially inhibited by Z-Glu-Tyr dipeptide, which is without precedent in metallocarboxypeptidases and resembles tubulin carboxypeptidase functioning; this hypothesis is strongly reinforced by the results depicted in Kalinina et al. published as accompanying paper in this journal. Our findings demonstrate that the M14 family of metallocarboxypeptidases is more complex and diverse than expected, and that Nna1-like peptidases are functional variants of such enzymes, representing a novel subfamily (we propose the name M14D) that contributes substantially to such diversity.

Transient receptor potential protein family C (TRPC) has been proposed as a candidate for channels involved in capacitative Ca2+ entry (CCE) mechanisms, but the modulation of their gene expression remains unexplored. In this study we show that guinea pig gallbladder smooth muscle contains mRNA encoding TRPC1, TRPC2, TRPC3, and TRPC4 proteins whose abundance depends on cytosolic Ca2+ level ([Ca2+]i). Thus lowering the levels of cellular calcium with the chelators EGTA and BAPTA AM results in a downregulation of TRPC1–TRPC4 gene and protein expression. In contrast, activation of Ca2+ influx through L-type Ca2+ channels and Ca2+ release from intracellular stores induced an increase in TRPC1–TRPC4 mRNA and protein abundance. Activation of Ca2+/calmodulin-dependent kinases (CaMK) and phosphorylation of cAMP-response element binding protein accounts for the increase in TRPC mRNA transcription in response to L-type channel-mediated Ca2+ influx . In addition to this mechanism, activation of TRPC gene expression by intracellular Ca2+ release also involves calcineurin pathway. According to the proposed role for these channels, activation of CCE induced an increase in TRPC1 and TRPC3 mRNA abundance, which depends on the integrity of the calcineurin and CaMK pathways. These findings show for the first time an essential autoregulatory role of Ca2+ in Ca2+ homeostasis at the level of TRPC gene and protein expression.

Vaccines blocking malaria parasites in the blood-stage diminish mortality and morbidity caused by the disease. Here, we isolated antigens from total parasite proteins by antibody affinity chromatography to test an immunization against lethal malaria infection in a murine model. We used the sera of malaria self-resistant ICR mice to lethalPlasmodium yoelii yoelii17XL for purification of their IgGs which were subsequently employed to isolate blood-stage parasite antigens that were inoculated to immunize BALB/c mice. The presence of specific antibodies in vaccinated mice serum was studied by immunoblot analysis at different days after vaccination and showed an intensive immune response to a wide range of antigens with molecular weight ranging between 22 and 250 kDa. The humoral response allowed delay of the infection after the inoculation to high lethal doses ofP. yoelii yoelii17XL resulting in a partial protection against malaria disease, although final survival was managed in a low proportion of challenged mice. This approach shows the potential to prevent malaria disease with a set of antigens isolated from blood-stage parasites.

An experiment was conducted to study dietary fat type (fish oil (FO) vs. vegetable oil) effect on lipid and glucose metabolism in post-smolt Atlantic salmon. Duplicate groups of salmon were fed one of eight diets in which the two fat sources FO (long chain n-3 fatty acids, FA) or linseed oil (LO) (short chain n-3 FA) were combined in a 2 × 4 factorial design with sunflower oil (SO) (rich in n-6 FA) at inclusion levels of 0, 25, 50 and 75% of total added fat. The effects of the diets on plasma metabolites, the activity of selected enzymes involved in lipid metabolism, biometric indices and muscle glucose transporter GLUT4 expression were determined after 12 weeks of feeding. Lower viscero-somatic indices (VSI) and fatty livers were observed in fish fed LO based diets. Increasing inclusion levels of SO affected plasma glucose concentration in fish fed FO based diets, and plasma triglycerides, which decreased in a linear and quadratic pattern in fish fed FO based diets, but increased linearly in fish fed LO based diets. Specific activity of liver carnitine palmitoyl transferase I (CPT I) and glucose-6-phosphate dehydrogenase (G6PD) and plasma nonesterified fatty acids (NEFA) concentration was higher in fish fed LO based diets. Two GLUT4 isoforms I and II have been described in muscle and proved to be differentially expressed related to dietary fatty acids. In summary, dietary fat type affects lipid metabolism in post-smolted Atlantic salmon. In addition, a possibility to interfere on glucose metabolism by means of dietary fat type is discussed.

The bifunctional enzyme glucose-6-phosphate dehydrogenase-6-phosphogluconolactonase (G6PD-6PGL) found in Plasmodium falciparum has unique structural and functional characteristics restricted to this genus. This study was designed to examine the effects of RNA-mediated PfG6PD-6PGL gene silencing in cultures of P. falciparum on the expression of parasite antioxidant defense genes at the transcription level. The highest degree of G6PD-6PGL silencing achieved was 86% at the mRNA level, with a recovery to almost normal levels within 24 h, indicating only transient diminished expression of the PfG6PD-6PGL gene. PfG6PD-6PGL silencing caused arrest of the trophozoite stage and enhanced gametocyte formation. In addition, an immediate transcriptional response was shown by thioredoxin reductase suggesting that P. falciparum G6PD-6PGL plays a physiological role in the specific response of the parasite to intracellullar oxidative stress. P. falciparum transfection with an empty DNA vector also promoted intracellular stress, as determined by mRNA up-regulation of antioxidant genes. Collectively, our findings point to an important role for this enzyme in the parasite's infection cycle. The different characteristics of G6PD-6PGL with respect to its homologue in the host make it an ideal target for therapeutic strategies.

Background In a clinical setting of gene therapy, quantitative methods are required to determine recombinant viral titres and transgene mRNA expression, avoiding the use of reporter genes. Methods We describe procedures based on quantitative polymerase chain reaction (qPCR) designed to assess functional titres of murine leukaemia virus (MLV) vectors, determine proviral copy numbers in transduced cells, and estimate retroviral transgene expression in both target cell lines and mice with transduced chimeric haematopoiesis. Results Compared to EGFP titration, proviral DNA detection by qPCR was more accurate in assessing the number of infective particles in supernatants, such that average viral titres in terms of proviral copies per cell were two-fold higher. Transgene mRNA expression was directly determined from the vectors used without the need for reporter assays. A new parameter, defined here as the ‘transcription index’ (TI), served to establish the association between transcribed transgenic mRNA and each proviral insertion. The TI represents the potential expression of every vector or insertion in each cell type, and is thus useful as a control parameter for monitoring preclinical or clinical protocols. Conclusions The practical use of qPCR is demonstrated as a valuable alternative to reporter genes for the assessment and surveillance of insertion numbers and transgene expression. In combination with protein expression, this approach should be capable of establishing safer therapeutic gene doses, avoiding the potential side effects of high transduction and expression levels. Copyright © 2006 John Wiley & Sons, Ltd.

The study was undertaken to evaluate the effects of dietary protein sources on lipogenesis and fat deposition in a marine teleost, the European seabass (Dicentrarchus labrax). Four isonitrogenous (crude protein (CP, Nx6.25), 44% DM) and isoenergetic (22-23 kJ/g DM) diets were formulated to contain one of the following as the major protein source: fish meal (FM), one of two soy protein concentrates (SPC) and corn gluten meal (CGM). Apparent digestibility coefficients of the diets and raw ingredients, as well as soluble nitrogen (ammonia and urea) and phosphorus excretion were measured. Growth rates of seabass fed plant protein-based diets were significantly lower than those fed fish meal based diet. The protein utilisation was strongly correlated to the dietary essential amino acids index. Measurements of N excretion (ammonia and urea nitrogen) confirmed these data. Daily fat gain at the whole body level ranged between 1.1 to 1.7 g/kg BW, with the highest values being recorded in fish fed the fish meal based diet. Levels of plasma triglycerides and cholesterol were lower in fish fed soy protein diets than in those fed the diet solely based on fish meal. Soy protein rich diets decreased the activities of selected hepatic lipogenic enzymes (glucose 6-phosphate dehydrogenase, malic enzyme, ATP-citrate lysase, acetylcoenzyme A carboxylase and fatty acid synthetase). Highest lipogenic enzyme activities where found in fish fed the fish meal diet, except for fatty acid synthetase which was increased in seabass fed the corn-gluten meal based diets. Overall data suggest that dietary protein sources affects fat deposition and the lipogenic potential in European seabass.

The genome of the human malaria parasite Plasmodium falciparum is extremely AT-rich such that it is particularly difficult to design standard probes to identify and quantify specific transcripts. Biased AT genome contents (70%–80%) lead to a high proportion of short repetitions and a low free energy of binding between target sequences and their specific probes during hybridization. This causes nonspecific annealing and high background noise. We constructed molecular beacon probes with dual-function stems to avoid nonspecific detection and establish identical melting patterns for use with several fluorescent probes for the analysis of mRNA expression in P. falciparum in real-time reverse transcription PCR (RT-PCR) assays. The method proved highly efficient at detecting low transcript levels in P. falciparum microcultures. Conditions were established for two types of real-time instruments, demonstrating that molecular beacons with dual-function stems are a useful tool for the functional analysis of high AT genomes. The procedure could be adapted to high-throughput gene expression protocols for the biomolecular screening of the P. falciparum and other AT-rich genomes.

ICR mice have heterogeneous susceptibility to lethal Plasmodium yoelii yoelii 17XL from the first days of experimental infection as evidenced by the different parasitemia levels and clinical outcomes. This mouse model has revealed specific immune responses on peripheral blood correlating with the infection fate of the animals. To search for immune-markers linked to parasitemia we examined B lymphocytes in organs of the immune system as key effectors of rodent immunity against malaria. To determine changes in immune cellularity fostered by the different prognostic parasitemia we examined B cell subsets in low (15%) and high (50%) parasitized mice during the first days of the infection. In the case of surviving mice, we studied the preservation of memory immune response 500 days after the primary P. yoelii challenge. Correlating with the parasitemia level, it was observed an increase in total cellularity of spleen during the first week of infection which remained after 16 months of the infection in surviving animals. B cell subsets were also modified across the different infection fates. Subpopulation as follicular B cells and B-1 cells proportions behaved differently depending on the parasitemia kinetics. In addition, peritoneal cavity cells proliferated in response to high parasitemia. More significantly, P. yoelii -specific memory B cells remained in the spleen 500 days after the primo-infection. This study demonstrates that B cell kinetics is influenced by the different parasitemia courses which are naturally developed within a same strain of untreated mice. We show that high levels of parasitemia at the beginning of infection promote an extremely fast and exacerbate response of several cell populations in spleen and peritoneal cavity that, in addition, do not follow the kinetics observed in peripheral blood. Furthermore, our results describe the longest persistence of memory B cells long time upon a single malaria infection in mice.

ABSTRACT: Using the published protein sequence from a rabbit microsomal glucose-6-phosphate dehydrogenase G6PD we have isolated and sequenced a cDNA clone coding for its human equivalent, which is also known as hexose-6-phosphate dehydrogenase (H6PD) and glucose dehydrogenase. The corresponding genomic sequence is in the databases enabling its localization to chromosome 1p36. The gene spans 37 kb and consists of 5 exons, the fifth of which codes for more than half of the 89kDa protein. The first intron is a 10kb insertion in the 5′ untranslated sequence. The predicted mRNA has an exceptionally long (6.5kb) 3′ untranslated sequence. The predicted protein shows extensive homology with X-linked G6PD, suggesting the two genes share a common ancestor but no intron positions are conserved between the two genes suggesting the gene duplication was an ancient event. The C-terminal portion of the protein is not homologous with G6PD but shows limited homology with proteins of unknown function found throughout evolution and encoded next to G6PD in various micro-organisms. Intriguingly this C-terminal portion has some homology with the N-terminal sequence of Plasmodium falciparum G6PD.

A growth trial was conducted with groups of European seabass having an initial weight of 6 g to study the lipogenic action of dietary protein and non-protein energy supplies. Six experimental diets were formulated to contain one of two crude protein levels (43 and 52%) with digestible protein (DP) to digestible energy (DE) ratios ranging from 19 to 26 mg/kJ. At the end of the growth trial (12 weeks), the activities of liver glucose-6-phosphate dehydrogenase (G6PD, EC 1.1.1.49), malic enzyme (ME, EC 1.1.1.40), ATP citrate lyase (ACL, EC 4.1.3.8), acetyl-CoA carboxylase (ACoAC, EC 6.4.1.2) and fatty acid synthetase (FAS, EC 2.3.1.38) were measured. Digestibility of main dietary components was also determined over a three-week period. At each protein level, an increase in dietary DE led to improved growth performance, protein efficiency, daily N deposition and to a reduction of N loss. Best results were achieved at 40% DP and a DP/DE ratio of 19–20 mg/kJ. G6PD, ME and ACoAC were found to be the key regulatory enzymes in the lipogenic pathway, with G6PD being the main NADPH-generating enzyme. Activities of G6PD, ME, ACL and FAS were reduced with increasing fat intake. Activities of G6PD, ME and ACL were increased with increasing starch intake. ACoAC activity was negatively correlated with starch intake and positively with fat intake.

Malaria infection in humans elicits a wide range of immune responses that can be detected in peripheral blood, but we lack detailed long-term follow-up data on the primary and subsequent infections that lead to naturally acquired immunity. Studies on antimalarial immune responses in mice have been based on models yielding homogenous infection profiles. Here, we present a mouse model in which a heterogeneous course of Plasmodium yoelii lethal malaria infection is produced in a non-congenic ICR strain to allow comparison among different immunological and clinical outcomes. Three different disease courses were observed ranging from a fatal outcome, either early or late, to a self-resolved infection that conferred long-term immunity against re-infection. Qualitative and quantitative changes produced in leukocyte subpopulations and cytokine profiles detected in peripheral blood during the first week of infection revealed that monocytes, dendritic cells and immature B cells were the main cell subsets present in highly-parasitized mice dying in the first week after infection. Besides, CD4(+)CD25(high) T cells expanded at an earlier time point in early deceased mice than in surviving mice and expressed higher levels of intracellular Foxp3 protein. In contrast, survivors showed a limited increase of cytokines release and stable circulating innate cells. From the second week of infection, mice that would die or survive showed similar immune profiles, although CD4(+)CD25(high) T cells number increased earlier in mice with the worst prognosis. In surviving mice the expansion of activated circulating T cell and switched-class B cells with a long-term protective humoral response from the second infection week is remarkable. Our results demonstrate that the follow-up studies of immunological blood parameters during a malaria infection can offer information about the course of the pathological process and the immune response.

We have investigated the mechanism of action of inhibition of the choline kinase of P. falciparum ( p.f. -ChoK) by two inhibitors of the human ChoKα, MN58b and RSM-932A, which have previously been shown to be potent antitumoral agents. The efficacy of these inhibitors against p.f. -ChoK is investigated using enzymatic and in vitro assays. While MN58b may enter the choline/phosphocholine binding site, RSM-932A appears to have an altogether novel mechanism of inhibition and is synergistic with respect to both choline and ATP. A model of inhibition for RSM-932A in which this inhibitor traps p.f. -ChoK in a phosphorylated intermediate state blocking phosphate transfer to choline is presented. Importantly, MN58b and RSM-932A have in vitro inhibitory activity in the low nanomolar range and are equally effective against chloroquine-sensitive and chloroquine-resistant strains. RSM-932A and MN58b significantly reduced parasitemia and induced the accumulation of trophozoites and schizonts, blocking intraerythrocytic development and interfering with parasite egress or invasion, suggesting a delay of the parasite maturation stage. The present data provide two new potent structures for the development of antimalarial compounds and validate p.f. -ChoK as an accessible drug target against the parasite.

Corrigendum: Gene-associated markers provide tools for tackling illegal fishing and false eco-certification

Seven bacterial strains capable of utilizing monochloroacetate (MCA) at a concentration of 50 mM as the sole carbon source were isolated from soil and displayed MCA dehalogenase activity. Three of them were identified as Pseudomonas spp., and the remaining four strains as Alcaligenes sp., Agrobacterium sp., Arthrobacter sp., and Azotobacter sp. This latter is the first reported example of a bacterium fixing atmospheric nitrogen under aerobic conditions that also uses a chloro-organic compound as sole source of carbon and energy. MCA dehalogenase activity in these strains was found to be inducible under different growth conditions. Crude extracts from all seven isolated strains also displayed dehalogenating activity with a relatively wide range of halogenated organic compounds (aliphatic acids, ketones, alcohols, alkanes, and aromatics), which, depending on the strain, were dehalogenated to different extents. The estimated Kmvalues for MCA were used to classify the dehalogenase activities into three groups: high affinity (30–40 μM) in Alcaligenes and Agrobacterium species, medium affinity (100–180 μM) in Pseudomonas and Azotobacter species, and low affinity (100 mM) in Arthrobacter sp. Both the optimal pH range for MCA dehalogenase activity (between pH 8 and 10) and the pH profile of stability (in the neutral–basic range) were found to be similar in all strains, whereas the thermal stability profiles were variable.Key words: dehalogenase, halohydrolase, monochloroacetate, soil.

The role of neurotrophic factors on the integrity of the central nervous system (CNS) during cerebral malaria (CM) infection remains obscure, but the long-standing neurocognitive sequelae often observed in rescued children can be attributed in part to the modulation of neuronal survival and synaptic plasticity. To discriminate the contribution of key responses in the time-sequence of the pathogenic events that trigger the development of neurocognitive malaria syndrome we defined four stages (I-IV) of the neurological progression of CM in C57BL/6 mice infected with Plasmodium berghei ANKA. Upregulation of ICAM-1, VCAM-1, e-selectin and p-selectin expression was detected in all cerebral regions before parasitized red blood cells (pRBC) accumulation. As the severity of symptoms increased, BDNF mRNA progressively diminished in several brain regions, earliest in the thalamus-hypothalamus, cerebellum, brainstem and cortex, and correlated with a four-stage disease sequence. Immunohistochemical confocal microscopy revealed changes in the BDNF distribution pattern, suggesting altered axonal transport. During CM progression, molecular markers of neurological infection and inflammation in the parasite and the host, respectively, were accompanied by a switch in the brain constitutive proteasome to the immunoproteasome, which could impede normal protein turnover. In parallel with BDNF downregulation, NCAM expression also diminished with increased CM severity. Together, these data suggest that changes in BDNF availability could be involved in the pathogenesis of CM.

We report a case of an African patient with sickle cell trait who was diagnosed in Spain with B-cell lymphoma. Blood smears were negative for malaria, and no plasmodium antigens were detected in the blood. To treat his lymphoma, the patient underwent chemotherapy and autologous stem cell transplantation. Following a splenectomy due to a worsening condition, he developed clinical malaria with detectable parasitemia. This case suggests that the humoral response and parasite removal by the spleen may afford protection from overt disease and may even help maintain subclinical human reservoirs of the disease.

Oxidative stress plays a critical role in the pathogenesis of a number of diseases. The carbonyl end products of protein oxidation are among the most commonly measured markers of oxidation in biological samples. Protein carbonyl functional groups may be derivatized with 2,4-dinitrophenylhydrazine (DNPH) to render a stable 2,4-dinitrophenylhydrazone-protein (DNP-protein) and the carbonyl contents of individual proteins then determined by two-dimensional electrophoresis followed by immunoblotting using specific anti-DNP antibodies. Unfortunately, derivatization of proteins with DNPH could affect their mass spectrometry (MS) identification. This problem can be overcome using nontreated samples for protein identification. Nevertheless, derivatization could also affect their mobility, which might be solved by performing the derivatization step after the initial electrophoresis. Here, we compare two-dimensional redox proteome maps of mouse cerebellum acquired by performing the DNPH derivatization step before or after electrophoresis and detect differences in protein patterns. When the same approach is used for protein detection and identification, both methods were found to be useful to identify carbonylated proteins. However, whereas pre-DNPH derivatized proteins were successfully analyzed, high background staining complicated the analysis when the DNPH reaction was performed after transblotting. Comparative data on protein identification using both methods are provided. 5.113 JCR (2011) Q1, 10/72 Biochemical research methods

We report the novel use of proteomics to investigate protein variation among populations of the European hake (Merluccius merluccius). The liver and brain extracts of 18 hake (N = 36) captured in the Mediterranean Sea, Cantabrian Sea, and Atlantic Ocean were examined by 2D/DIGE and mass spectrometry. Significant differences in protein expression among populations were revealed by 84 spots obtained in the gels for the liver and 145 spots for the brain. Population groups of samples were defined by multivariate analysis (PCA and hierarchical clustering). According to protein expression levels and the functions of the 55 candidate protein spots identified, which showed significant expression differences, highest population discrimination was rendered by brain proteins involved in cell signaling and metabolism/energy and by liver proteins involved in protein fate. Finally, we present a statistically robust framework to accurately classify individuals according to their population of origin. Thus, purposely identified protein isoforms were found to be competent at discriminating populations. These results suggest the possibility of identifying protein biomarkers related to environmental changes in a nonmodel species such as the hake and pave the way for more extensive research on protein variation among populations of marine fishes.

Multiple glucose-6-phosphate dehydrogenase (G6PD)-deficient alleles have reached polymorphic frequencies because of the protection they confer against malaria infection. A protection mechanism based on enhanced phagocytosis of parasitized G6PD-deficient erythrocytes that are oxidatively damaged is well accepted. Although an association of this phenotype with the impairment of the antioxidant defense in G6PD deficiency has been demonstrated, the dysfunctional pathway leading to membrane damage and modified exposure of the malaria-infected red cell to the host is not known. Thus, in this study, erythrocytes from the common African variant G6PD A- were used to analyze by redox proteomics the major oxidative changes occurring in the host membrane proteins during the intraerythrocytic development of Plasmodium falciparum, the most lethal malaria parasite. Fifteen carbonylated membrane proteins exclusively identified in infected G6PD A- red blood cells revealed selective oxidation of host proteins upon malarial infection. As a result, three pathways in the host erythrocyte were oxidatively damaged in G6PD A-: (1) traffic/assembly of exported parasite proteins in red cell cytoskeleton and surface, (2) oxidative stress defense proteins, and (3) stress response proteins. Additional identification of hemichromes associated with membrane proteins also supports a role for specific oxidative modifications in protection against malaria by G6PD polymorphisms.

Proteins modified by 4-hydroxy-2-nonenal (HNE) are cellular markers of oxidative stress in health and disease. HNE is generated by free radical chain reactions during oxidative stress as a major end-product of the oxidative fatty acid metabolism. Identification and quantitative analysis of HNE-modified proteins are readily performed by using specific antibodies raised against them. Further on, the identification of the amino acid residues involved in the HNE-modification is an additional step in proteomic post-transcriptional modification analysis to explain the nature of the specificity underlying oxidative stress mechanisms. For this purpose, a combined protocol of immune-detection, peptide enrichment, mass spectrometry, and de novo protein sequencing has been developed. The methodology was first examined in the model protein bovine serum albumin (BSA), allowing the comparison of matrix-assisted laser desorption/ionization-tandem time of flight (MALDI-TOF/TOF) mass spectrometry and liquid chromatography-tandem mass spectrometry (LC-MS/MS) performance and sensitivity. Peptide enrichment was optimized by affinity chromatography on HNE-BSA resulting in increased sensitivity. Identification of amino acid residues modified by HNE was finally ascertained by de novo sequencing analysis. The improved methodology was demonstrated on human erythrocyte membrane proteins allowing the identification of HNE-lysine and HNE-histidine Michael adducts in the β-spectrin under physiological conditions.

Binding of NADP to glucose-6-phosphate dehydrogenase (G6PD) from Dicentrarchus labrax liver has stabilized its native structure against thermal inactivation, guanidine hydrochloride unfolding and inactivation by tryptic digestion. The time-course of G6PD inactivation by guanidine hydrochloride in the presence of NADP has provided experimental evidence in favor of a conformational drift upon NADP binding to the bass enzyme. Based on the inactivation patterns obtained when the enzyme was treated with guanidine hydrochloride and trypsin, it is proposed that the enzyme conformation induced upon NADP binding is in slow equilibrium with the conformation stabilized in the absence of NADP. FPLC studies have shown that micromolar concentrations of NADP induced oligomerization of G6PD. In addition, the different K0.5 values of NADP binding to the enzyme, ranging from 1-2 microM (from trypsin inactivation) to 90 microM (from titration of the intrinsic fluorescence), suggest a step-wise binding of NADP to the oligomer, with negative cooperativity in the saturation process.

This protocol describes a method for preparing cultures of Plasmodium falciparum synchronized at any intraerythrocytic stage. Using this method, around 60% parasitized cells may be obtained. On the basis of Trager and Jensen's original continuous culture method, our approach relies on the use of fresh human blood not older than 2 weeks, a low hematocrit between 0.8 and 1.5%, a starting frozen inoculum of 10% ring-stage parasitemia, human serum replaced with AlbuMAX I and alternating sorbitol and Percoll synchronization methods to shorten the cycle window to 4–6 h and reduce sorbitol toxicity. From our synchronized high parasite density cultures, 3–5 ml of infected red blood cells can be obtained in 1 week, corresponding to 1.2 mg of total parasite protein per ml of harvested culture. On the basis of the variables parasitemia and packed cell volume, we provide an equation to accurately calculate the amount of complete medium required every 24 h corrected for the cycle stage and capacity of the culture flask. Ten days suffice to complete the protocol from a frozen stock of parasites.

Background Improvements on malarial diagnostic methods are currently needed for the correct detection in low-density Plasmodium falciparum infections. Microfluorimetric DNA-based assays have been previously used for evaluation of anti-malarial drug efficacy on Plasmodium infected erythrocytes. Several factors affecting the sensitivity of these methods have been evaluated, and tested for the detection and quantification of the parasite in low parasitaemia conditions. Methods Parasitaemia was assessed by measuring SYBRGreen I® (SGI) and PicoGreen® (PG) fluorescence of P. falciparum Dd2 cultures on human red blood cells. Different modifications of standard methods were tested to improve the detection sensitivity. Calculation of IC50 for chloroquine was used to validate the method. Results Removal of haemoglobin from infected red-blood cells culture (IRBC) increased considerably the fluorescent signal obtained from both SGI and PG. Detergents used for cell lysis also showed to have an effect on the fluorescent signal. Upon depletion of haemoglobin and detergents the fluorescence emission of SGI and PG increased, respectively, 10- and 60-fold, extending notably the dynamic range of the assay. Under these conditions, a 20-fold higher PG vs. SGI fluorescent signal was observed. The estimated limits of detection and quantification for the PG haemoglobin/detergent-depleted method were 0.2% and 0.7% parasitaemia, respectively, which allow the detection of ~10 parasites per microliter. The method was validated on whole blood-infected samples, displaying similar results as those obtained using IRBC. Removal of white-blood cells prior to the assay allowed to increase the accuracy of the measurement, by reducing the relative uncertainty at the limit of detection from 0.5 to 0.1. Conclusion The use of PG microassays on detergent-free, haemoglobin-depleted samples appears as the best choice both for the detection of Plasmodium in low-density infections and anti-malarial drugs tests.

The aim of this study was to evaluate the biological correlation and prognostic impact of Gata-1, Gata-2, EKLF, and c-MPL transcript level in a group of 41 acute mieloid leukemia (AML) patients. Gata-1 overexpression was related to advanced age and a low percentage of bone marrow blasts and was associated with the expression of CD34 antigen and lymphoid T markers. The negative impact of Gata-1 expression on the probability of achieving complete remission has been confirmed. Gata-2 overexpression was associated with a low percentage of blasts in BM and males. Expression of c-MPL was associated with CD34+ AML and M2 FAB AML subtype. A higher expression of EKLF was found in secondary AML versus primary AML. Nevertheless, patients expressing EKLF had a longer overall survival and event free survival than those patients that did not express EKLF. Our study has identified expression of EKLF as a factor with a favorable impact on prognosis in AML. Am. J. Hematol, 2009. © 2008 Wiley-Liss, Inc.

To maximize growth, farmed fish are fed high-fat diets, which can lead to high tissue lipid concentrations that have an impact on quality. The intake of conjugated linoleic acid (CLA) reduces body fat in mammals and this study was undertaken to determine the effects of dietary CLA on growth, composition, and postprandial metabolic variables in sea bream. Fish were fed 3 diets containing 48 g/100 g protein and 24 g/100 g fat, including fish oil supplemented with 0 (control), 2, or 4% CLA for 12 wk. Feed intake, specific growth rate, total body fat, and circulating somatolactin concentration were lower in fish fed CLA than in controls. Feed efficiency was greater in fish fed 2% CLA than in controls. Liver triglyceride concentrations were higher in fish fed 4% CLA and muscle triglyceride concentrations were lower in fish fed both CLA diets than in controls. Hepatic fatty acyl desaturase and elongase mRNA levels in fish fed CLA were lower than in controls. Metabolic differences between controls and CLA-fed fish were observed at 6 h but not at 24 h after the last meal, including lower postprandial circulating triglyceride concentrations, higher hepatic acyl-CoA-oxidase, and lower L-3-hydroxyacyl-CoA dehydrogenase activities in CLA-fed fish than in controls. Dietary CLA did not affect enzymes involved in lipogenesis including hepatic fatty acid synthase and malic enzyme, but it decreased glucose 6-phosphate dehydrogenase activity at 24 h, but not at 6 h after feeding. The data suggest that CLA intake in sea bream has little effect on hepatic lipogenesis, channels dietary lipid from adipose tissue to the liver, and switches hepatic mitochondrial to peroxisomal beta-oxidation.

Nna1 has some sequence similarity to metallocarboxypeptidases, but the biochemical characterization of Nna1 has not previously been reported. In this work we performed a detailed genomic scan and found100 Nna1 homologues in bacteria, Protista, and Animalia, including several paralogs in most eukaryotic species. Phylogenetic analysis of the Nna1-like sequences demonstrates a major divergence between Nna1-like peptidases and the previously known metallocarboxypeptidases subfamilies: M14A, M14B, and M14C. Conformational modeling of representative Nna1-like proteins from a variety of species indicates an unusually open active site, a property that might facilitate its action on a wide variety of peptide and protein substrates. To test this, we expressed a recombinant form of one of the Nna1-like peptidases from Caenorhabditis elegans and demonstrated that this protein is a fully functional metallocarboxypeptidase that cleaves a range of C-terminal amino acids from synthetic peptides. The enzymatic activity is activated by ATP/ADP and salt-inactivated, and is preferentially inhibited by Z-Glu-Tyr dipeptide, which is without precedent in metallocarboxypeptidases and resembles tubulin carboxypeptidase functioning; this hypothesis is strongly reinforced by the results depicted in Kalinina et al. published as accompanying paper in this journal. Our findings demonstrate that the M14 family of metallocarboxypeptidases is more complex and diverse than expected, and that Nna1-like peptidases are functional variants of such enzymes, representing a novel subfamily (we propose the name M14D) that contributes substantially to such diversity.

Human erythrocyte R-type pyruvate kinase (RPK) deficiency is an autosomal recessive disorder produced by mutations in the PKLR gene, causing chronic nonspherocytic hemolytic anemia. Survival of patients with severe RPK deficiency has been associated with compensatory expression in red blood cells (RBCs) of M2PK, an isoenzyme showing wide tissue distribution. We describe a novel homozygous null mutation of the PKLR gene found in a girl with a prenatal diagnosis of PK deficiency. The mutant PK gene revealed an 11-nucleotide (nt) duplication at exon 8, causing frameshift of the PKLR transcript, predicting a truncated protein inferred to have no catalytic activity. Western blot analysis and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) detected no M2PK expression in the peripheral blood red cell fraction. The expression of mutant RPK mRNA in the RBCs was almost 6 times higher than that detected in a control patient with hereditary spherocytosis. This molecular phenotypic analysis of the null mutation in the PKLR gene provides evidence for a lack of M2PK in the mature RBCs of this patient and suggests that normal red cell functions and survival are achieved through a population of young erythroid cells released into the circulation in response to anemia. (Blood. 2005;106:1851-1856)

The cloning and characterization of cDNAs and genes encoding three peroxisome proliferator-activated receptor (PPAR) isotypes from two species of marine fish, the plaice (Pleuronectes platessa) and the gilthead sea bream (Sparus aurata), are reported for the first time. Although differences in the genomic organization of the fish PPAR genes compared with their mammalian counterparts are evident, sequence alignments and phylogenetic comparisons show the fish genes to be homologs of mammalian PPARα, PPARβ/δ, and PPARγ. Like their mammalian homologs, fish PPARs bind to a variety of natural PPAR response elements (PPREs) present in the promoters of mammalian or piscine genes. In contrast, the mRNA expression pattern of PPARs in the two fish species differs from that observed in other vertebrates. Thus, PPARγ is expressed more widely in fish tissues than in mammals, whereas PPARα and β are expressed similarly in profile to mammals. Furthermore, nutritional status strongly influences the expression of all three PPAR isotypes in liver, whereas it has no effect on PPAR expression in intestinal and adipose tissues. Fish PPARα and β exhibit an activation profile similar to that of the mammalian PPAR in response to a variety of activators/ligands, whereas PPARγ is not activated by mammalian PPARγ-specific ligands. Amino acid residues shown to be critical for ligand binding in mammalian PPARs are not conserved in fish PPARγ and therefore, together with the distinct tissue expression profile of this receptor, suggest potential differences in the function of PPARγ in fish compared with mammals.