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Biomedical subjects

E Barrio

Publications and source records attributed to E Barrio.

At least 19 recordsLinked to original sources
PubMed2005

Adaptive evolution in GroEL from distantly related endosymbiotic bacteria of insects.

Many symbioses between bacteria and insects resulted from ancient infections followed by strict vertical transmission within host lineages. The strong bottlenecks under which this transmission occurs promote the neutral fixation of slightly deleterious mutations by genetic drift. As predicted by Muller's ratchet, this fixation will drive endosymbiotic bacteria through an irreversible dynamics of fitness loss. The chaperonin GroEL has been proposed as a compensatory mechanism whereby endosymbiotic bacteria of aphids persist. Here, we show that endosymbiotic bacteria of insects from two phylogenetically very distant bacterial phyla have fixed amino acid substitutions by positive selection in functionally important GroEL regions involved in either GroES/peptide binding or in the en bloc movement of the GroEL apical domain. These results, together with the high levels of constitutive expression of GroEL in these endosymbionts, provide valuable insights into the evolution of a molecular mechanism responsible for the maintenance of the symbiotic lifestyle.

Adaptation, Biological↗
PubMed2004

Liver disease in heavy drinkers with and without alcohol withdrawal syndrome.

BACKGROUND: Withdrawal syndrome is a hallmark of alcohol dependence. The characteristics of alcohol consumption, closely related to dependence, could influence the development of alcoholic liver disease. The study aimed to investigate if patients with severe alcohol withdrawal syndrome have a peculiar profile of liver disease. METHODS: The study included 256 heavy drinkers (aged 19-75 years, 70.3% males) admitted to an Internal Medicine Department. Patients admitted for complications of liver disease were not included. Severe alcohol withdrawal syndrome (seizures, disordered perceptions, or delirium) developed in 150 patients (58.6%). Alcohol consumption (daily quantity, duration, and pattern [regular or irregular]) was assessed by questionnaire. Liver biopsy was performed in all cases. RESULTS: Patients with alcohol withdrawal syndrome showed a lower prevalence of liver cirrhosis and a higher prevalence of alcoholic hepatitis than patients without it. The negative association of alcohol withdrawal syndrome with liver cirrhosis persisted after we adjusted for sex, daily intake, duration, and pattern of alcohol consumption. Alcoholic hepatitis was independently associated with the irregular pattern of alcohol consumption, which was closely associated with severe alcohol withdrawal syndrome. CONCLUSIONS: The profile of liver injury is different in heavy drinkers who develop and who do not develop a severe alcohol withdrawal syndrome when admitted to the hospital.

Adult↗
PubMed2004

Study of genetic expression of intrauterine growth factors IGF-I and EGFR in placental tissue from pregnancies with intrauterine growth retardation.

To investigate the possibility of altered gene expression of growth factors in prenatal growth retardation, we assessed expression of the genes for insulin-like growth factor-I (IGF-I) and epidermal growth factor receptor (EGFR) by RT-PCR from human placentas at term delivery in two groups: appropriate for gestational age (AGA) and pregnancies complicated with IUGR. The placentas from IUGR gestations showed reduced IGF-I expression with a significance of p = 0.008, whereas we did not find any significant differences in EGFR gene expression.

ErbB Receptors↗
PubMed2004

Intrauterine growth retardation: study of placental apoptosis.

We studied the rate of apoptosis in the placental tissue of pregnancies complicated with intrauterine growth retardation (IUGR) and compared it with the results obtained in normal placentas. Our results clearly demonstrate a strongly increased rate of apoptosis in placentas of children born with IUGR, suggesting severe placental dysfunction. The significance of these findings needs further study.

Apoptosis↗
PubMed2001

Detecting changes in the functional constraints of paralogous genes.

We describe a new procedure to determine whether regional alterations in the evolutionary constraints imposed on paralogous proteins have occurred. We used as models the A and B (alternatively called alpha and beta) subunits of V/F/A-ATPases, originated by a gene duplication more than 3 billion years ago. Changes associated to three major splits (eubacteria versus Archaea-eukaryotes; Archaea versus eukaryotes; and among free-living bacteria and symbiotic mitochondria) were studied. Only in the first case, when we compared eubacterial or mitochondrial F-ATPases versus eukaryotic vacuolar V-ATPases or archaeal A-ATPases, constraint changes were observed. Modifications in the degree of regional constraining were not detected for the other two types of comparisons (V-ATPases versus A-ATPases and within F-ATPases, respectively). When the rates of evolution of the two subunits were compared, it was found that F-ATPases regulatory subunits evolved faster than catalytic subunits, but the opposite was true for A- and V-ATPases. Our results suggest that, even for universal and essential proteins, selective constraints may be occasionally altered. On the other hand, in some cases no changes were detected after periods of more than 2.2 billion years.

Adenosine Triphosphatases↗
PubMed2001

Evidence for positive selection in the capsid protein-coding region of the foot-and-mouth disease virus (FMDV) subjected to experimental passage regimens.

We present sequence data from two genomic regions of foot-and-mouth disease virus (FMDV) subjected to several experimental passage regimens. Maximum-likelihood estimates of the nonsynonymous-to-synonymous rate ratio parameter (d(N)/d(S)) suggested the action of positive selection on some antigenic sites of the FMDV capsid during some experimental passages. These antigenic sites showed an accumulation of convergent amino acid replacements during massive serial cytolytic passages and also in persistent infections of FMDV in cell culture. This accumulation was most significant at the antigenic site A (the G-H loop of capsid VP1), which includes an Arg-Gly-Asp (RGD) cellular recognition motif. Our analyses also identified a subregion of VP3, part of the fivefold axis of FMDV particles, that also appeared to be subjected to positive selection of amino acid replacements. From these results, we can conclude that under the restrictive conditions imposed either by the presence of the monoclonal antibodies, by the persistent infections, or by the competition processes established between different variants of the viral population, amino acid replacement in some capsid-coding regions can be positively selected toward an increase of those mutants with a higher capability to infect the cell.

Aphthovirus↗
PubMed2000

Identification of Colletotrichum species responsible for anthracnose of strawberry based on the internal transcribed spacers of the ribosomal region.

In recent years, different molecular techniques have led to an important progress in the characterisation of Colletotrichum species, but there are no available methods which permit the easy identification of Colletotrichum strains and their assignation to classical species. In the present work, the restriction patterns generated from the region spanning the internal transcribed spacers (ITS1 and ITS2) and the 5.8S rRNA gene, were used to identify a total of 80 strains of Colletotrichum, the majority of them isolated from strawberry. One of the most interesting results derived from this study was the easy and reliable distinction, using the endonuclease MvnI, between Colletotrichum fragariae and Colletotrichum gloeosporoides, both responsible of anthracnose on strawberry and phenotypically indistinguishable. Moreover, we propose the restriction fragments generated by the endonucleases MvnI, PvuII and ScrFI as a rapid method to differentiate species of the Colletotrichum genus.

Colletotrichum↗
PubMed2000

The evolution of RNA viruses: A population genetics view.

RNA viruses are excellent experimental models for studying evolution under the theoretical framework of population genetics. For a proper justification of this thesis we have introduced some properties of RNA viruses that are relevant for studying evolution. On the other hand, population genetics is a reductionistic theory of evolution. It does not consider or make simplistic assumptions on the transformation laws within and between genotypic and phenotypic spaces. However, such laws are minimized in the case of RNA viruses because the phenotypic space maps onto the genotypic space in a much more linear way than on higher DNA-based organisms. Under experimental conditions, we have tested the role of deleterious and beneficial mutations in the degree of adaptation of vesicular stomatitis virus (VSV), a nonsegmented virus of negative strand. We also have studied how effective population size, initial genetic variability in populations, and environmental heterogeneity shapes the impact of mutations in the evolution of vesicular stomatitis virus. Finally, in an integrative attempt, we discuss pros and cons of the quasispecies theory compared with classic population genetics models for haploid organisms to explain the evolution of RNA viruses.

Biological Evolution↗
PubMed2000

Influence of acute alcohol intake and alcohol withdrawal on circulating levels of IL-6, IL-8, IL-10 and IL-12.

Cytokine balance alterations are responsible for some of the systemic and hepatic manifestations of alcoholism. The present study was aimed to evaluate the influence of both acute alcohol abstinence (in alcoholics) and acute alcohol intake (in healthy subjects) on serum IL-6, IL-8, IL-10, and IL-12 levels. Serum cytokine concentrations were determined on admission and after a median of 6 days of ethanol abstinence in 29 patients with alcohol withdrawal syndrome. The same determinations were made in five healthy volunteers at baseline and after 36 h of a single 60 g-dose alcohol intake. Increased serum levels of IL-6, IL-10 and, to a lesser extent IL-8, declined in the few days after alcohol abstinence in patients with alcohol withdrawal syndrome. Serum IL-8 values increased after alcohol intake in healthy subjects. Rapid variation of serum cytokine levels along with alcohol intake or abstinence should be taken into account in cytokine studies in alcohol abusers.

Adult↗
PubMed2000

RFLP analysis of the ribosomal internal transcribed spacers and the 5.8S rRNA gene region of the genus Saccharomyces: a fast method for species identification and the differentiation of flor yeasts.

The PCR amplification and subsequent restriction analysis of the region spanning the internal transcribed spacers (ITS1 and ITS2) and the 5.8S rRNA gene was applied to the identification of yeasts belonging to the genus Saccharomyces. This methodology has previously been used for the identification of some species of this genus, but in the present work, this application was extended to the identification of new accepted Saccharomyces species (S. kunashirensis, S. martiniae, S. rosinii, S. spencerorum, and S. transvaalensis), as well as to the differentiation of an interesting group of Saccharomyces cerevisiae strains, known as flor yeasts, which are responsible for ageing sherry wine. Among the species of the Saccharomyces sensu lato complex, the high diversity observed, either in the length of the amplified region (ranged between 700 and 875 bp) or in their restriction patterns allows the unequivocal identification of these species. With respect to the four sibling species of the Saccharomyces sensu stricto complex, only two of them, S. bayanus and S. pastorianus, cannot be differentiated according to their restriction patterns, which is in accordance with the hybrid origin (S. bayanus x S. cerevisiae) of S. pastorianus. The flor S. cerevisiae strains exhibited restriction patterns different from those typical of the species S. cerevisiae. These differences can easily be used to differentiate this interesting group of strains. We demonstrate that the specific patterns exhibited by flor yeasts are due to the presence of a 24-bp deletion located in the ITS 1 region and that this could have originated as a consequence of a slipped-strand mispairing during replication or be due to an unequal crossing-over. A subsequent restriction analysis of this region from more than 150 flor strains indicated that this deletion is fixed in flor yeast populations.

Cluster Analysis↗
PubMed2000

Phylogeny of the genus Kluyveromyces inferred from the mitochondrial cytochrome-c oxidase II gene.

A phylogenetic analysis of 17 species belonging to the genus Kluyveromyces and 12 reference and outgroup species was performed using mitochondrial cytochrome-c oxidase II gene sequences. The genus Kluyveromyces appears as a polyphyletic taxon formed by species included within the following four main groups. The Kluyveromyces phaffii group encompasses the species Kluyveromyces blattae, K. phaffii and Kluyveromyces yarrowii. The Kluyveromyces marxianus group is a monophyletic group consisting of the species Kluyveromyces aestuarii, Kluyveromyces dobzhanskii, Kluyveromyces lactis, K. marxianus and Kluyveromyces wickerhamii. The monophyletic Kluyveromyces thermotolerans group is formed by K. thermotolerans, Kluyveromyces waltii and Saccharomyces kluyveri (which appears in the mitochondrial tree as the sister clade of the K. marxianus group). Finally, the Saccharomyces cerevisiae group contains the remaining Kluyveromyces species, as well as the reference Saccharomyces species (sensu lato and sensu stricto) and Candida glabrata (the phylogenetic relationships within this group are unclear according to the bootstrap test). The phylogenetic relationships obtained for this mitochondrial gene are, for the most part, congruent with previous trees based on nuclear rRNA sequences, except for the position of K. yarrowii and the close relationship between the K. marxianus and K. thermotolerans groups. These differences, as well as the existence of these groups, are discussed in the context of previous studies based on phenotypic, genetic and molecular data. Although additional studies are required to decipher the phylogenetic relationships between the genus Kluyveromyces and the closely related genera Saccharomyces, Torulaspora and Zygosaccharomyces, future changes to their taxonomic status should take account of the existence of these four groups of Kluyveromyces species.

Electron Transport Complex IV↗
PubMed2000

Prevalence, patterns, and course of past hepatitis B virus infection in intravenous drug users with HIV-1 infection.

OBJECTIVE: Hepatitis B virus (HBV) and human immunodeficiency virus (HIV) share common routes of transmission. Therefore, markers of either active or past HBV infection are present in many HIV-infected patients, particularly in intravenous drug users (IDUs). The aim of this study was to analyze the serological pattern of past HBV infection (presence or absence of anti-HBs) and the course of past HBV infection (changes in anti-HBs status, and HBV reactivation) in two cohorts of IDUs with and without HIV infection. METHODS: HBV serum markers were studied in 388 HIV-positive and 197 HIV-negative IDUs. Among them, 263 HIV-positive and 50 HIV-negative patients with past HBV infection (serum HBsAg negative and anti-HBc positive, with or without anti-HBs) were followed-up for a median of 21 and 13 months, respectively, to detect changes in anti-HBs status and HBV reactivation. RESULTS: The prevalence of HBV infection (either active or past) was higher in HIV-positive than in HIV-negative cases (90% vs 62%, p < 0.001), even when stratified by years of drug use. Most cases (92% of HIV-positive and 89% of HIV-negative) had markers of past infection. Among those patients with past HBV infection, 60% of HIV-positive and 72% of HIV-negative presented serum anti-HBs (p = 0.03). The incidence of anti-HBs loss was 1.8 cases/100 person-year in HIV-positive, and 1.8 cases/100 person-year in HIV-negative patients (RR 1.0, 95% CI 0.1-94, p = NS). Incidence of anti-HBs development was 17.6 cases/100 person-year in HIV-positive and 25.6 cases/100 person-year in HIV-negative IDUs (RR, 1.5, 95% CI, 0.6-3.5, p = NS). Only one HIV-positive patient with markers of past HBV infection developed an active infection (0.2 events/100 person-year). CONCLUSIONS: HBV infection (either active or past) is particularly frequent in HIV-positive IDUs. Most cases have markers of past infection. Isolated detection of anti-HBc (absence of anti-HBs) is more common in HIV-positive than in HIV-negative IDUs. Despite their progressive immunosuppression, both anti-HBs loss and HBV reactivation are rare in HIV-infected IDUs.

Adolescent↗
PubMed2000

Mitotic recombination and genetic changes in Saccharomyces cerevisiae during wine fermentation.

Natural strains of Saccharomyces cerevisiae are prototrophic homothallic yeasts that sporulate poorly, are often heterozygous, and may be aneuploid. This genomic constitution may confer selective advantages in some environments. Different mechanisms of recombination, such as meiosis or mitotic rearrangement of chromosomes, have been proposed for wine strains. We studied the stability of the URA3 locus of a URA3/ura3 wine yeast in consecutive grape must fermentations. ura3/ura3 homozygotes were detected at a rate of 1 x 10(-5) to 3 x 10(-5) per generation, and mitotic rearrangements for chromosomes VIII and XII appeared after 30 mitotic divisions. We used the karyotype as a meiotic marker and determined that sporulation was not involved in this process. Thus, we propose a hypothesis for the genome changes in wine yeasts during vinification. This putative mechanism involves mitotic recombination between homologous sequences and does not necessarily imply meiosis.

Chromosomes, Fungal↗
PubMed1999

On the evolution of Dopa decarboxylase (Ddc) and Drosophila systematics.

We have sequenced most of the coding region of the gene Dopa decarboxylase (Ddc) in 24 fruitfly species. The Ddc gene is quite informative about Drosophila phylogeny. Several outstanding issues in Drosophila phylogeny are resolved by analysis of the Ddc sequences alone or in combination with three other genes, Sod, Adh, and Gpdh. The three species groups, melanogaster, obscura, and willistoni, are each monophyletic and all three combined form a monophyletic group, which corresponds to the subgenus Sophophora. The Sophophora subgenus is the sister group to all other Drosophila subgenera (including some named genera, previously considered outside the Drosophila genus, namely, Scaptomyza and Zaprionus, which are therefore downgraded to the category of subgenus). The Hawaiian Drosophila and Scaptomyza are a monophyletic group, which is the sister clade to the virilis and repleta groups of the subgenus Drosophila. The subgenus Drosophila appears to be paraphyletic, although this is not definitely resolved. The two genera Scaptodrosophila and Chymomyza are older than the genus Drosophila. The data favor the hypothesis that Chymomyza is older than Scaptodrosophila, although this issue is not definitely resolved. Molecular evolution is erratic. The rates of nucleotide substitution in 3rd codon position relative to positions 1 + 2 vary from one species lineage to another and from gene to gene.

Animals↗
PubMed1999

Serum cytokines and increased total serum IgE in alcoholics.

BACKGROUND: It has been reported that total serum IgE is increased in alcohol abusers, but the mechanisms responsible are not known. Production of IgE depends on B-cell stimulation by both antigens and some cytokines, particularly IL-4 and IL-13. Chronic alcoholism and alcoholic liver disease are accompanied by changes in cytokine production. AIM OF THE STUDY: To evaluate if IgE increase in alcoholics could be associated to a ethanol-induced imbalance of the cytokine profile. PATIENTS AND METHODS: A total of 65 patients (53 males and 12 females, aged 47 +/- 12 years), admitted to the hospital because of ethanol abstinence symptoms entered the study. On admission, total serum IgE was measured by chemiluminescent EIA and serum IL-4, IL-5, IL-6, IL-8, IL-10, IL-12, IL-13, and interferon-gamma were measured by ELISA. Data were compared with those of 40 healthy control subjects. RESULTS: Serum IgE, IL-6, IL-8, IL-10, IL-12, and IL-13 were found to be high in alcoholic patients compared with healthy volunteers. Some parallelism was observed between serum IgE and both serum IL-10 and IL-13 were increased in alcoholics. CONCLUSIONS: Total serum IgE elevation in alcoholics with abstinence syndrome is accompanied by an increase of some type 2 cytokines. Ethanol-induced alterations in the cytokine profile may contribute to increased IgE levels in alcoholics.

Adult↗
PubMed1998

Inter- and intraspecific chromosome pattern variation in the yeast genus Kluyveromyces.

The analysis of the electrophoretic chromosome patterns of the species of the genus Kluyveromyces, reveals a high polymorphism in size, number and intensity of bands. Different sets of electrophoresis running conditions were used to establish species-specific patterns and also to detect intraspecific variation. According to their karyotypes, the species of this genus can be divided into two major groups. The first group includes the species K. africanus, K. bacillisporus, K. delphensis, K. lodderae, K. phaffi, K. polysporus and K. yarrowii, composing the so-called 'Saccharomyces cerevisiae-like' group, because their karyotypes resemble that of the species S. cerevisiae. The second group comprises the species K. aestuarii, K. blattae, K. dobzhanskii, K. lactis, K. marxianus, K. thermotolerans, K. waltii and K. wickerhamii, whose chromosomal patterns exhibit common characteristics very different to those of the species included in the 'S. cerevisiae-like' group. This division is concordant with the position of these species in previous phylogenetic reconstructions. Additionally, the intraspecific analysis of the chromosome patterns show a rich polymorphism in the heterogeneous species K. dobzhanskii, K. lactis, and K. marxianus, which is in concordance with the variability observed with other phenotypic or genetic markers. On the contrary, K. thermotolerans exhibits a homogeneous karyotype indicative of a very low level of chromosomal polymorphism, which is congruent with the reduced variability found in this species with other molecular markers.

Animals↗
PubMed1998

Rapid identification of wine yeast species based on RFLP analysis of the ribosomal internal transcribed spacer (ITS) region.

In this study, we identified a total of 33 wine yeast species and strains using the restriction patterns generated from the region spanning the internal transcribed spacers (ITS 1 and 2) and the 5.8S rRNA gene. Polymerase chain reaction (PCR) products of this rDNA region showed a high length variation for the different species. The size of the PCR products and the restriction analyses with three restriction endonucleases (HinfI, CfoI, and HaeIII) yielded a specific restriction pattern for each species with the exception of the corresponding anamorph and teleomorph states, which presented identical patterns. This method was applied to analyze the diversity of wine yeast species during spontaneous wine fermentation.

DNA, Fungal↗