ALS-associated VRK1 R321C mutation causes proteostatic imbalance and mitochondrial defects in iPSC-derived motor neurons.

Vaccinia-related kinase 1 (VRK1) is a gene which has been implicated in the pathological process of a broad range of neurodevelopmental disorders as well as neuropathies, such as Amyotrophic Lateral Sclerosis (ALS). Here we report a family presenting ALS in an autosomal recessive mode of inheritance, segregating with a homozygous missense mutation located in VRK1 gene (p.R321C; Arg321Cys). Proteomic analyses from iPSC-derived motor neurons identified 720 proteins eligible for subsequent investigation, and our exploration of protein profiles revealed significant enrichments in pathways such as mTOR signaling, E2F, MYC targets, DNA repair response, cell proliferation and energetic metabolism. Functional studies further validated such alterations, showing that affected motor neurons presented decreased levels of global protein output, ER stress and downregulation of mTOR signaling. Mitochondrial alterations also pointed to decreased reserve capacity and increased non-mitochondrial oxygen consumption. Taken together, our results present the main pathological alterations associated with VRK1 mutation in ALS.

Ingestive Behavior of Heifers Supplemented with Glycerin in Substitution of Corn on Brachiaria brizantha Pasture.

The objective was to evaluate the ingestive behavior of crossbred heifers finished on a Brachiaria brizantha cv. Marandu pasture receiving four levels of glycerin in their supplementation. Thirty-six crossbred heifers with average initial weight of 264.83±3.83 kg and 20 months of age were distributed into a completely randomized design with four treatments and nine replications: control (0%), 4.82%, 10.12%, and 15.56% glycerin in the dry matter. The grazing time reduced linearly (p<0.05), whereas the time spent on activities like rumination, idleness, trough and total chewing time were quadratically affected (p<0.05). Bite rate and number of bites/day were quadratically influenced (p<0.05). The number of bites/swallowed cud and the number of bites/minute, however, increased linearly (p<0.05). Although the time spent on each cud and number of chews per cud were not affected (p>0.05). The number of rumination periods reduced linearly (p<0.05), whereas the number of grazing, idle and trough periods, and the times per grazing, idle, rumination and trough periods were quadratically affected (p<0.05). The feed and rumination efficiencies of the dry matter, non-fibrous carbohydrates, pasture dry matter and concentrate were quadratically affected (p>0.05) whereas the feed efficiency of neutral detergent fiber reduced linearly (p<0.05). Addition of glycerin in substitution of corn in supplements for animals managed on pastures does not influenced feed intake, but reduces the grazing time and increases the idle time. The supplementation also improves feed and rumination efficiencies.

Unbiased label-free quantitative proteomic profiling and enriched proteomic pathways in seminal plasma of adult men before and after varicocelectomy.

STUDY QUESTION: Does the seminal plasma proteomic profile and functional enrichment of gene ontology terms change after microsurgical varicocelectomy? Are there any potential targets for diagnosis or therapeutic intervention in varicocele? SUMMARY ANSWER: A shift in state from a responsive-to-stress condition before varicocele correction to a responsive-to-environment condition after varicocelectomy was observed in enriched proteomic pathways. WHAT IS KNOWN ALREADY: Varicocele may lead to many adverse effects, including failure of testicular growth and development, and is associated with decreased semen quality and increased semen oxidative stress. Varicocelectomy is the treatment of choice, and is associated with improved semen quality, but little is known regarding the underlying molecular mechanisms and post-genomic pathways following intervention. STUDY DESIGN, SIZE, DURATION: A prospective study was carried out including 18 adult men with varicocele. These patients provided one semen sample before they were submitted for bilateral varicocele repair through microsurgical varicocelectomy, and one other semen sample 90 days after the surgery. PARTICIPANTS/MATERIALS, SETTING, METHODS: An aliquot of each semen sample was used for unbiased proteomics analysis by a label-free quantitative approach (2D nanoUPLC-ESI-MS(E)). Samples were pooled according to group (normalized to protein content) and run in quadruplicate. These quadruplicate runs provided degrees of freedom in order to compare groups using a non-parametric Mann-Whitney test for quantified proteins. MAIN RESULTS AND THE ROLE OF CHANCE: A total of 316 proteins were quantified or identified, of which 91 were exclusively identified or quantified in one of the groups (53 in the pre- and 38 in the post-varicocelectomy group), and 68 were quantified in both groups and submitted to statistical analysis, of which 5 were overrepresented in the pre-varicocelectomy group (P < 0.05). In enriched functional analysis, binding and response to stimulus functions were enriched in a common cluster (present in both groups), nitric oxide metabolism and tetratricopeptide repeat domain-binding functions were enriched in the pre-varicocelectomy group, and response to reactive oxygen species, gluconeogenesis, nicotinamide adenine dinucleotide-binding and protein stabilization were enriched in the post-varicocelectomy. LIMITATIONS, REASONS FOR CAUTION: Because a shotgun proteomics analysis was chosen in order to generate a list of putative biomarkers, a targeted follow-up study should be performed to confirm these biomarkers. WIDER IMPLICATIONS OF THE FINDINGS: The proteins found in both groups possess functions usually found in human semen. The enriched function analysis demonstrated a shift back to homeostasis after varicocelectomy, suggesting that varicocele correction promotes return of semen to a physiological state. STUDY FUNDING/COMPETING INTEREST(S): The funding for this project was received from the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) as a scholarship for Ms Camargo. There was no conflict of interest.

Genetic polymorphisms modulate the folate metabolism of Brazilian individuals with Down syndrome.

Individuals with Down syndrome (DS) carry three copies of the Cystathionine ß-synthase (CßS) gene. The increase in the dosage of this gene results in an altered profile of metabolites involved in the folate pathway, including reduced homocysteine (Hcy), methionine, S-adenosylhomocysteine (SAH) and S-adenosylmethionine (SAM). Furthermore, previous studies in individuals with DS have shown that genetic variants in genes involved in the folate pathway influence the concentrations of this metabolism's products. The purpose of this study is to investigate whether polymorphisms in genes involved in folate metabolism affect the plasma concentrations of Hcy and methylmalonic acid (MMA) along with the concentration of serum folate in individuals with DS. Twelve genetic polymorphisms were investigated in 90 individuals with DS (median age 1.29 years, range 0.07-30.35 years; 49 male and 41 female). Genotyping for the polymorphisms was performed either by polymerase chain reaction (PCR) based techniques or by direct sequencing. Plasma concentrations of Hcy and MMA were measured by liquid chromatography-tandem mass spectrometry as previously described, and serum folate was quantified using a competitive immunoassay. Our results indicate that the MTHFR C677T, MTR A2756G, TC2 C776G and BHMT G742A polymorphisms along with MMA concentration are predictors of Hcy concentration. They also show that age and Hcy concentration are predictors of MMA concentration. These findings could help to understand how genetic variation impacts folate metabolism and what metabolic consequences these variants have in individuals with trisomy 21.

Zona fasciculata 21-hydroxysteroids and precursor-to-product ratios in 21-hydroxylase deficiency: further characterization of classic and non-classic patients and heterozygote carriers.

INTRODUCTION: Although much is known about the increased levels of the 21-hydroxylase substrates 17-hydroxyprogesterone (17OHP) and 21-deoxycortisol (21DF) - the biochemical markers of all forms of 21-hydroxylase deficiency (21OHD), only limited information is available on the zona fasciculata (ZF) products distal to the enzymatic block: 11-deoxycortisol (S), 11-deoxycorticosterone (DOC), and corticosterone (B). OBJECTIVE: To investigate whether basal and post-ACTH levels of S, DOC, and B and the 21-hydroxylase precursor-to-product ratios determined by tandem mass spectrometry preceded by high-performance liquid chromatography separation (liquid chromatography-tandem mass spectrometry) could disclose distinct profiles in genotypically confirmed classic (no.=14) and non-classic (NC) (no.=18) patients, heterozygote carriers (no.=61) and wildtypes (WT) (no.=27) for 21OHD. RESULTS: Salt wasting (SW) and simple virilizing (SV) had higher basal levels of DOC with no further increase in response to ACTH. Stimulated DOC was similar in 21OHD patients and carriers but was reduced as compared to WT. ACTH-stimulated B increased gradually from SW and SV through WT. The post-ACTH 21DF/B ratio was able to detect 92% of the carriers among WT. All NC patients could be detected by post-ACTH 17OHP/DOC and 21DF/B, with no overlap with 21OHD carriers. CONCLUSION: Although 21-hydroxylase is a key enzymatic step in both 17-hydroxy and 17-deoxy pathways of ZF, the reaction is mostly affected in the latter pathway, leading to a significant impairment of B production, which may further characterize the 21OHD subtypes. Also, the precursor-to-product ratios, particularly 21DF/B, can demonstrate the distinctive outline of 21OHD subtypes, including carriers and normal subjects.

Novel mutations in the SH3BP2 gene associated with sporadic central giant cell lesions and cherubism.

Central giant cell lesion (CGCL) is a reactive bone lesion that occurs mainly in the mandible, characterized by the multinucleated osteoclast-like giant cells in a background of oval to spindle-shaped mononuclear cells. The etiology is unknown and occurs more commonly in young adults. Cherubism, a rare disease found predominantly in females has histologic characteristics indistinguishable from those of CGCL and is caused by mutations mostly present in exon 9 of the SH3BP2 gene. In this study, we investigated four cases of CGCL and one case of cherubism. DNA was extracted from peripheral blood and tumor tissue and all coding and flanking regions of the SH3BP2 amplified by PCR and directly sequenced to identify underlying mutations. Two novel mutations were found; a heterozygous missense mutation c.1442A>T (Q481L) in exon 11 in one sporadic case of CGCL and a heterozygous germline and tumor tissue missense mutation c.320C>T (T107M) in exon 4 in one patient with cherubism. These findings open a new window to investigate the possible relationship between the pathogenesis of the cherubism and CGCL.

Double aneuploidy (48,XXY,+21) of maternal origin in a child born to a 13-year-old mother: evaluation of the maternal folate metabolism.

The occurrence of non-mosaic double trisomy is exceptional in newborns. In this paper, a 48,XXY,+21 child, the parental origin of the extra chromosomes and the evaluation of the maternal folate metabolism are presented. The infant was born to a 13-year-old mother and presented with the typical clinical features of Down syndrome (DS). The origin of the additional chromosomes was maternal and most likely resulted from errors during the first meiotic division. Molecular analysis of 12 genetic polymorphisms involved in the folate metabolism revealed that the mother is heterozygous for the MTHFR C677T and TC2 A67G polymorphisms, and homozygous for the mutant MTRR A66G polymorphism. The maternal homocysteine concentration was 4.7 miromol/L, a value close to the one considered as a risk factor for DS in our previous study. Plasma methylmalonic acid and serum folate concentrations were 0.17 micromol/L and 18.4 ng/mL, respectively. It is possible that the presence of allelic variants for the folate metabolism and Hey concentration might have favored errors in chromosomal disjunction during gametogenesis in this young mother. To our knowledge, this is the first patient with non-mosaic Down-Klinefelter born to a teenage mother, resulting from a rare fertilization event combining an abnormal 25,XX,+21 oocyte and a 23,Y spermatozoon.

Sperm functional aspects and enriched proteomic pathways of seminal plasma of adult men with obesity.

BACKGROUND: Previous studies have demonstrated an association between obesity and the decreased male fertility. OBJECTIVE: to observe the mechanisms by which obesity affects semen quality. MATERIALS AND METHODS: A prospective study was performed including 47 male volunteers, of which 27 were obese group (body mass index >30 kg/m2 ) and 20 were eutrophic (body mass index between 18.5 and 25 kg/m2 ) controls. Sperm functional analysis was performed. The remaining seminal plasma was pooled-four pools per group- and submitted to proteomic analysis by liquid chromatography coupled to tandem mass spectrometry. Groups were compared by an unpaired Student's t-test. Differentially expressed proteins were submitted to functional enrichment analysis using the online platform PantherDB. RESULTS: Obese men presented decreased non-progressive motility, morphology, acrosome integrity, mitochondrial activity, and increased sperm DNA fragmentation. In proteomics analysis, 69 proteins were differentially expressed between the two groups. Among them, one protein was absent, 19 were down-regulated, 49 were up-regulated, and one was exclusive in the study group. The main functions enriched were as follows: negative regulation of the intrinsic pathway of apoptosis, activation of immune and inflammatory, antioxidant activity, among others. CONCLUSION: molecular pathways suggest there is a causative link, and that the effector mechanisms alter sperm metabolic status and defective testicular selection 5 mechanisms.

Molecular pathways of varicocele and its repair - A paired labelled shotgun proteomics approach.

Varicocelectomy is associated to improved semen quality and sperm functional quality, but individual response is highly variable. Thus, a prospective study was performed including 25 men who collected a semen sample before and 12 months after subinguinal microsurgical varicocelectomy. Semen analysis, sperm functional analysis, and seminal plasma proteomic analysis was performed before and 12 months after varicocelectomy, and according to improvement or not of semen quality (positive and negative outcome). Varicocelectomy led to an increase in semen volume and sperm count, morphology, and mitochondrial activity. In the pre- vs. post-samples, 698 proteins were quantified - 91 differentially expressed after varicocelectomy. In the positive vs. negative outcome analysis, 647 proteins were identified - 151 differentially expressed in the negative outcome group and 30 differentially expressed in the positive outcome group. Tripeptidyl peptidase-1 offered a predictive value for outcome, with an area under a ROC curve of 84.5%. It seems TPP1 is an outcome predictor for varicocelectomy in adults. More importantly, this study demonstrates that the seminal plasma proteome is different in men with varicocele when compared to post-treatment samples from the same individuals. Understanding and monitoring the molecular mechanisms of semen may further establish therapeutic options for these men. SIGNIFICANCE: Although several large-scale studies have demonstrated varicocele is unequivocally associated to male infertility, these same studies have also demonstrated that varicocele is not a determinant of male infertility. We have yet to answer the question of why don't all men with varicocele present with infertility. Varicocele treatment improves semen quality, but its results are variable, and one cannot know who will and who will not benefit from surgical treatment. Results from this study strongly advance a concept that our previous studies have shown: that men with varicocele present an inflammatory semen profile. We have further demonstrated that men operated for varicocele present a decrease in this inflammatory profile, and that when they do not, semen quality remains unaltered. Trypeptidil peptidase-1, a seminal protein, was 3-fold higher in men with a positive outcome after the procedure, when compared to men with a negative outcome. Therefore, inflammation seems to be a central point to varicocele-derived male infertility.

Random amplification of polymorphic DNA reveals clonal relationships among enteropathogenic Escherichia coli isolated from non-human primates and humans.

Enteropathogenic Escherichia coli (EPEC) strains are important agents of infantile diarrhea all over the world, gaining even greater importance in developing countries. EPEC have also been isolated from various animal species, but most isolates belong to serotypes that differ from those recovered from humans. However, it has been demonstrated that several isolates from non-human primates belong to the serogroups and/or serotypes related to those implicated in human disease. The objective of this study was to evaluate the genetic differences between thirteen strains isolated from non-human primates and the same number of strains isolated from human infections. Human isolates belonged to the same serogroup/serotype as the monkey strains and the evaluation was done by analysis of random amplified polymorphic DNA. Dendrogram analysis showed that there was no clustering between human and monkey strains. Human and non-human isolates of the EPEC serotypes O127:H40 and O128:H2 shared 90 and 87% of their bands, respectively, indicating strong genomic similarity between the strains, leading to the speculation that they may have arisen from the same pathogenic clone. To our knowledge, this study is the first one comparing genomic similarity between human and non-human primate strains and the results provide further evidence that monkey EPEC strains correlate with human EPEC, as suggested in a previous investigation.

Determination of testicular function in adolescents with varicocoele - a proteomics approach.

The goal of this study was to determine seminal plasma biomarkers of testicular function in adolescents with varicocoele and to verify enriched gene ontology terms associated to these differential proteomes. An observational study was carried out in an academic research environment. A total of 77 adolescent patients were recruited from a local public school, of which 23 were without varicocoele and with normal semen analysis (control group), 37 were with varicocoele and normal semen (VNS) parameters, and 17 were with varicocoele and altered semen (VAS) parameters. Two semen collections were provided with a 1-week interval, after 2-5 days of ejaculatory abstinence. Seminal plasma proteins were identified and quantified utilizing a label-free shotgun proteomics approach, generating (i) proteins differentially expressed in each group (control, VNS, and VAS) and putative biomarkers using multivariate statistics followed by discriminant analysis. Confirmatory analysis was performed for two proteins by western blotting. Enriched biological processes and molecular functions were determined using gene ontology analysis. In total, 541 proteins were identified and quantified: 108 exclusive or overexpressed in controls, 26 in the VNS group, and 13 in the VAS group. The suggested biomarkers are Cab45/SDF4 (Q9BRK5), protein lefty-1 (O75610), DNase I (P24855), PAP2-alpha (O14494), IBP-7 (Q16270), HDC (P01860), and CRISP-3 (P54108). Western blotting results showed that Cab45 was significantly underexpressed in both varicocoele groups, and CRISP-3 was significantly overexpressed in seminal plasma of adolescents with VAS. In conclusion, specific biomarkers of spermatogenesis and homeostasis are observed in adolescents without varicocoele, and the presence of a palpable varicocoele progressively shifts these adolescents toward initially an immune response, and finally toward a chronic inflammatory profile. This shift is accompanied by decreased semen quality.

[Interspecific outbreaks of dermatomycoses +caused by Microsporum canis and Microsporum gypseum]. / Surtos interespecíficos de dermatomicoses por Microsporum canis e Microsporum gypseum.

Dermatomycosis in domestic animals are important zoonosis in view of the fact that they maintain close contact with human beings. Seven ringworm outbreaks are here described, one of M. gypseum involving a cat and a women and the remainder of M. canis involving 20 human beings (adults, young people and children), 5 dogs, 16 cats and a gibbon-monkey (Hylobates lar).

Streptococcus pneumoniae: A cause of primary lung abscess in a child.

A case of primary pneumococcal lung abscess in a five-year-old child is described. Secondary anaerobic infection as a cause of cavitation was excluded by bronchoscopic culture of the cavity. Streptococcus pneumoniae is a rare but recognized cause of lung abscess in healthy children.

Virulence genotypes, antibiotic resistance and the phylogenetic background of extraintestinal pathogenic Escherichia coli isolated from urinary tract infections of dogs and cats in Brazil.

Urinary tract infection (UTI) is a frequent disease of humans and pets and has extra-intestinal pathogenic Escherichia coli (ExPEC) strains as one of the main etiologic agent. ExPEC are characterized by specific virulence factors and are related to a heterogeneous group of human and animal disorders, besides to be a relevant participant in the dissemination of antimicrobial resistance. The purpose of this study was to characterize E. coli strains isolated from UTI of dogs and cats for serotypes, virulence markers, phylogenetic groups and sensitivity to antimicrobial drugs. E. coli was identified as the etiologic agent of UTI in urine samples of 43 pets (7 cats and 36 dogs). Serogroups O2, O4 and O6 corresponded to more than one third of the isolates, being 62% of the total strains classified as B2, 18% as D, 16% as B1 and 4% as A. The iucD (22%), fyuA (80%), traT (51%) and cvaC (20%) genes were distributed among the four phylogenetic groups, whereas the papC/papEF (47%) and malX (67%) genes were found only in groups B2 and D. There were a high number of resistant strains, with 76% of the strains belonging to groups A, B1 and D characterized as multidrug resistant (MDR), whereas only 21% had this phenotype in the group B2. The ExPEC strains isolated in this study displayed pathotypic and phylogenetic similarities with human isolates and high percentages of drug resistance. The finding of MDR ExPEC strains suggests implications for animal and public health and deserves more investigations.

Does soy increase blood counts in myelodysplastic syndromes? / Será que a soja aumenta as contagens sanguíneas em síndrome mielodisplásica?

Myelodysplastic syndromes (MDS) are a group of clonal stem cell diseases characterized by ineffective hematopoiesis, bone marrow hyperproliferation, cytopenias in peripheral blood and risk of transformation into acute leukemia. We decided to investigate the effects of a soy concentrate on MDS patients based on the follow-up results of a 61 year-old Japanese female patient who was diagnosed with MDS and refractory cytopenia with multilineage dysplasia in 2003 (hemoglobin = 11g/dL; white blood cells count = 2,500/uL and platelets = 25,000/uL; marrow with mild dysplasia and normal karyotype; paroxysmal nocturnal hemoglobinuria was excluded). She started using soy as a dietary supplementation in May 2004 and presented a gradual increment in blood counts, achieving normalization approximately eight months afterwards. Among the soy components, the main compounds with anti-carcinogenic activity are the isoflavones (genistein and daidzein). Based on these lines of evidence, we proposed to administer daily a standard soy concentrate to 14 MDS out-patients for a minimum period of three months and maximum of 12 months, in an attempt to evaluate prospectively the possible increase in hemoglobin, neutrophils and platelet counts. A historical control group was used to compare results. The use of a soy concentrate in a standardized manner was associated with an increase in neutrophil and/or platelet counts in some cases, but spontaneous increments were also observed in historical controls. This preliminary study does not allow establishing a relation between soy supplementation and blood cell count increase.

As síndromes mielodisplásicas (SMD) são um grupo das doenças clonais de células-tronco caracterizado por hematopoese ineficaz, hiperproliferação de medula óssea, citopenias no sangue periférico e risco de transformação para leucemia aguda. Decidimos investigar os efeitos de um concentrado de soja em pacientes com SMD com base no fato de termos o seguimento de uma paciente japonesa, de 61 anos de idade, que foi diagnosticada em 2003 com SMD, citopenia refratária com displasia subtipo multilinhagens (hemoglobina = 11 g/dL; contagem de glóbulos brancos = 2.500/uL e plaquetas = 25.000/uL; medula com displasia leve e cariótipo normal; hemoglobinúria paroxística excluída), e que começou a usar a soja como suplemento alimentar em maio de 2004, apresentando gradual aumento da contagem das células sanguíneas, atingindo a normalização cerca de oito meses depois. Entre os componentes da soja, os principais compostos com propriedades anticarcinogênese são as isoflavonas (Ge nisteína e daidzeína). Com base nessas linhas de evidência, foi proposto oferecer diariamente um concentrado de soja padrão, por um período mínimo de três meses e máximo de doze meses, a 14 pacientes ambulatoriais, na tentativa de avaliar, prospectivamente, o possível aumento de hemoglobina, neutrófilos e plaquetas. Um grupo controle histórico foi utilizado para comparar os resultados. O uso de um concentrado de soja de forma padronizada foi associado ao aumento na contagem de neutrófilos e/ou de plaquetas em alguns casos, mas aumentos espontâneos também foram observados em controles históricos. Este estudo preliminar não permite estabelecer relação entre o uso de soja e o aumento na contagem sanguínea.

Novel 1,N(6)-etheno-2'-deoxyadenosine adducts from lipid peroxidation products.

trans,trans-2,4-Decadienal (DDE) is a widespread alpha, beta-unsaturated aldehyde found, for example, in food, water, and environmental pollutants. DDE is also endogenously generated as a breakdown product of lipid peroxidation in cell membranes. In the work presented here, the reaction of DDE with 2'-deoxyadenosine (dAdo) was investigated in an effort to assess its possible DNA damage potential. Besides 1,N(6)-etheno-2'-deoxyadenosine and two products, namely, 1-[3-(2-deoxy-beta-D-erythro-pentofuranosyl)-3H-imidazo[2, 1-i]purin-7-yl]-1,2,3-octanetriol (adduct I) and 1-[3-(2-deoxy-beta-D-erythro-pentofuranosyl)-3H-imidazo[2, 1-i]purin-7-yl]-1,2-heptanediol (adduct II), previously described by our group, two novel etheno adducts were identified. Thus, 1-[3-(2-deoxy-beta-D-erythro-pentofuranosyl)-3H-imidazo[2, 1-i]purin-7-yl]-1-hexanol (adduct III) and 1-[3-(2-deoxy-beta-D-erythro-pentofuranosyl)-3H-imidazo[2, 1-i]purin-7-yl]-2,3-epoxy-1-octanol (adduct IV) were isolated by reverse-phase high-performance liquid chromatography and characterized on the basis of extensive spectroscopic measurements. The formation of the adducts is likely to involve initial DDE oxidation followed by generation of reactive intermediates such as diepoxides, epoxides, and/or hydroperoxides. The subsequent reaction of the latter oxidation products with dAdo will give rise to the four described adducts. We also demonstrated here that upon oxidation, DDE reacts with calf thymus DNA, producing the four dAdo adducts. Interestingly, two of them are the expected products arising from the reaction of dAdo with 4-hydroxy-trans-2-nonenal (HNE) and trans-2-octenal, two other important breakdown lipid peroxidation products. The reactivity of DDE with DNA is lower than that of the latter aldehydes. However, DDE produced a wider variety of adducts. The characterization of the different DNA-etheno adducts and the determination of the mechanism of formation are of great importance for a better understanding of the deleterious biological effects associated with this class of compounds.

Formation of 1,N6-etheno-2'-deoxyadenosine adducts by trans,trans-2, 4-Decadienal.

trans,trans-2,4-Decadienal (DDE) is an important breakdown product of lipid peroxidation. This aldehyde is cytotoxic to mammalian cells and is known to be implicated in DNA damage. Therefore, attempts were made in this work to assess the reactivity of DDE with 2'-deoxyadenosine (dAdo). It was shown that DDE is able to bind to 2'-deoxyadenosine, yielding highly fluorescent products. Besides 1, N6-etheno-2'-deoxyadenosine (epsilondAdo), two other related adducts, 1-[3-(2-deoxy-beta-D-erythro-pentofuranosyl)-3H-imidazo[2, 1-i]purin-7-yl]-1,2,3-octanetriol and 1-[3-(2-deoxy-beta-D-erythro-pentofuranosyl)-3H-imidazo[2, 1-i]purin-7-yl]-1,2-heptanediol, were isolated by reverse phase high-performance liquid chromatography and characterized on the basis of their UV, fluorescence, nuclear magnetic resonance, and mass spectrometry features. The reaction mechanism for the formation of the DDE-2'-deoxyadenosine adducts involves 2,4-decadienal epoxidation and subsequent addition to the N2 amino group of 2'-deoxyadenosine, followed by cyclization at the N-1 site. Adducts differ by the length of carbon side chain and the number of hydroxyl groups. The present data indicate that DDE can be epoxidized by peroxides, and the resulting products are able to form several adducts with 2'-deoxyadenosine and/or DNA. Endogenous DNA adduct formation can contribute to the already reported high cytotoxicity of DDE to mammalian cells.

Purine DNA adducts of 4,5-dioxovaleric acid and 2,4-decadienal.

The present overview describes recent findings on the formation of cyclic adducts of purine DNA bases after reaction with two aldehyde compounds, 4,5-dioxovaleric acid (DOVA) and 2,4-decadlenal (DDE), which are involved in 5-aminolaevulinic acid (ALA) accumulation and lipid peroxidation, respectively. ALA accumulates under pathological conditions and is associated with an increased incidence of liver cancer. The final oxidation product of ALA, DOVA, is an efficient alkylating agent of the guanine moieties in both nucleoside and isolated DNA. Adducts were produced through the formation of a Schiff base involving the N2-amino group of 2'-deoxyguanosine and the ketone function of DOVA, respectively. DDE is an important breakdown product of lipid peroxidation. It is cytotoxic to mammalian cells and is known to be implicated in DNA damage. It can bind to 2'-deoxyadenosine, yielding highly fluorescent products, including 1,N6-etheno-2'-deoxyadenosine and two other, related adducts. The reaction mechanism for the formation of DDE-2'-deoxyadenosine adducts involves epoxidation of DDE and subsequent addition of the resulting reactive intermediates to the N6 amino group of 2'-deoxyadenosine, followed by cyclization at the N1 site. Formation of endogenous DNA adducts may contribute to the genotoxic potential of ALA and DDE.

Random amplification of polymorphic DNA reveals clonal relationships among enteropathogenic Escherichia coli isolated from non-human primates and humans

Enteropathogenic Escherichia coli (EPEC) strains are important agents of infantile diarrhea all over the world, gaining even greater importance in developing countries. EPEC have also been isolated from various animal species, but most isolates belong to serotypes that differ from those recovered from humans. However, it has been demonstrated that several isolates from non-human primates belong to the serogroups and/or serotypes related to those implicated in human disease. The objective of this study was to evaluate the genetic differences between thirteen strains isolated from non-human primates and the same number of strains isolated from human infections. Human isolates belonged to the same serogroup/serotype as the monkey strains and the evaluation was done by analysis of random amplified polymorphic DNA. Dendrogram analysis showed that there was no clustering between human and monkey strains. Human and non-human isolates of the EPEC serotypes O127:H40 and O128:H2 shared 90 and 87 percent of their bands, respectively, indicating strong genomic similarity between the strains, leading to the speculation that they may have arisen from the same pathogenic clone. To our knowledge, this study is the first one comparing genomic similarity between human and non-human primate strains and the results provide further evidence that monkey EPEC strains correlate with human EPEC, as suggested in a previous investigation.