luis gonzalez - Academia.edu (original) (raw)

Papers by luis gonzalez

Emerging Infectious Diseases

Experimental Parasitology, 2000

To study diagnostic epitopes within the Taenia solium 8 kDa antigen family, six overlapping synth... more To study diagnostic epitopes within the Taenia solium 8 kDa antigen family, six overlapping synthetic peptides from an 8 kDa family member (Ts8B2) were synthesized and evaluated by ELISA and MABA with sera from patients with neurocysticercosis (NCC), from infected pigs and from rabbits immunized with recombinant Ts8B2 protein. The pre-immune rabbit sera and the Ts8B2 recombinant protein served as negative and positive controls, respectively. A similar analysis was done with the already described antigenic peptides from another member of the 8 kDa family, highly similar to Ts8B2, the CyDA antigen. Surprisingly, neither the Ts8B2 peptides nor the CyDA peptides were recognized by infected human and porcine sera. However, the entire Ts8B2 recombinant, as well as amino and carboxy-terminal halves were recognized by the positive serum samples. The observed lack of recognition of linear Ts8B2 peptides suggests that the principal serological response to the Ts8B2 family is focused on conformational epitopes in contrast to the previously observed antigenicity of the CyDA peptides. This differential antigenicity of 8 kDa family petides could be related with parasite antigenic variability. The fact that rabbits experimentally immunized with Ts8B2 did make anti-peptide antibodies to peptides Ts8B2-6 and CyDA-6, located in the carboxy-terminal region demonstrated that the Ts8B2 peptides are not intrinsically non-immunogenic.► In this work we study diagnostic epitopes of the Taenia solium 8 kDa antigen family. ► We evaluated by ELISA and MABA overlapping synthetic peptides of Ts8B2 and CyDA. ► The peptides were evaluated using human, infected pigs and immunized rabbits. ► Ts8B2 showed conformational epitopes in contrast to the previously observed in CyDA. ► The differential antigenicity could be related with parasite variability.

Diagnostic microbiology and infectious disease, 2002

The potential value of PCRs in the species-specific diagnosis of Taenia saginata and Taenia soliu... more The potential value of PCRs in the species-specific diagnosis of Taenia saginata and Taenia solium have been investigated, using samples of T. saginata and T. solium from different geographical areas. The PCRs examining inter-species differences were based on the sequence of the HDP2 DNA fragment, specific for T. saginata/T. solium, and the sequence of the rDNA internal transcribed spacer 1 and spacer 2 (ITS-1 and ITS-2). This PCR analysis of DNA isolates confirmed morphologic diagnosis and allowed the speciation of samples too small or fragmented for morphologic identification, with clear and consistent inter-species differences between T. saginata (twenty-two) and T. solium (three) geographical isolates. Possible intra-species genomic variability, within these species, was similarly studied through analysis of PCR amplification products (PCR-RFLP) and only encountered one exceptional T. saginata isolate from Kenya, which yielded a unique PCR-RFLP pattern, different from T. saginata DNA of Mexican (one sample) and Spanish (seven samples) origin.

Transactions of the Royal Society of Tropical Medicine and Hygiene, 2002

The objective of this work was the rapid and easy differential diagnosis of Taenia saginata and T... more The objective of this work was the rapid and easy differential diagnosis of Taenia saginata and T. solium. First, a T. saginata size-selected genomic deoxyribonucleic acid (gDNA) library was constructed in the vector hgtl0 using the 2-4 kb fraction from the parasite DNA digested with EcoRl, under 'star' conditions.

Diagnostic microbiology and infectious disease, 2004

We have designed species-specific oligonucleotides which permit the differential detection of two... more We have designed species-specific oligonucleotides which permit the differential detection of two species of cestodes, Taenia saginata and Taenia solium. The oligonucleotides contain sequences established for two previously reported, noncoding DNA fragments cloned from a genomic library of T. saginata. The first, which is T. saginata specific (fragment HDP1), is a repetitive sequence with a 53-bp monomeric unit repeated 24 times in direct tandem along the 1,272-bp fragment. From this sequence the two oligonucleotides that were selected (oligonucleotides PTs4F1 and PTs4R1) specifically amplified genomic DNA (gDNA) from T. saginata but not T. solium or other related cestodes and had a sensitivity down to 10 pg of T. saginata gDNA. The second DNA fragment (fragment HDP2; 3,954 bp) hybridized to both T. saginata and T. solium DNAs and was not a repetitive sequence. Three oligonucleotides (oligonucleotides PTs7S35F1, PTs7S35F2, and PTs7S35R1) designed from the sequence of HDP2 allowed the differential amplification of gDNAs from T. saginata, T. solium, and Echinococcus granulosus in a multiplex PCR, which exhibits a sensitivity of 10 pg.

Antimicrobial agents and chemotherapy, 2004

Human immunodeficiency virus type 1 subtype B and C proteases were manipulated to contain 90M, 88... more Human immunodeficiency virus type 1 subtype B and C proteases were manipulated to contain 90M, 88D, or 89L, and their in vitro biological properties were studied. We showed that D30N has significantly more impact in subtype C than in subtype B counterparts, accounting for the reported low prevalence of this mutation in patients failing nelfinavir-based regimens.

The Journal of general virology, 2006

Human immunodeficiency virus type 1 subtype C isolates belong to one of the most prevalent strain... more Human immunodeficiency virus type 1 subtype C isolates belong to one of the most prevalent strains circulating worldwide and are responsible for the majority of new infections in the sub-Saharan region and other highly populated areas of the globe. In this work, the impact of drug-resistance mutations in the protease gene of subtype C viruses was analysed and compared with that of subtype B counterparts. A series of recombinant subtype C and B viruses was constructed carrying indinavir (IDV)-resistance mutations (M46V, I54V, V82A and L90M) and their susceptibility to six FDA-approved protease inhibitor compounds (amprenavir, indinavir, lopinavir, ritonavir, saquinavir and nelfinavir) was determined. A different impact of these mutations was found when nelfinavir and lopinavir were tested. The IDV drug-resistance mutations in the subtype C protease backbone were retained for a long period in culture without selective pressure when compared with those in subtype B counterparts in washout experiments.

Parasitology research, 2007

The Taenia saginata homologue of the major surface antigen of Echinococcus spp. is immunogenic an... more The Taenia saginata homologue of the major surface antigen of Echinococcus spp. is immunogenic and 97% identical to its Taenia solium homologue Abstract The TEG-Tsag gene of Taenia saginata is homologous to the genes expressing the two major surface antigens of Echinococcus spp. (EM10 and EG10). Surface antigens of parasites are logical candidates for vaccines, and in this paper we demonstrate that cattle vaccinated with the recombinant TEG-Tsag protein, either used singly or in conjunction with the recombinant HP6-Tsag protein, the major 18 kDa surface/secreted antigen of T. saginata oncospheres, produce excellent antibody responses to both these recombinant proteins. Thus TEG-Tsag may have utility as a vaccine and also as a diagnostic tool for bovine cysticercosis. In addition, as we now demonstrate a 97% homology between TEG-Tsag and its Taenia solium homologue, TEG-Tsol, this latter molecule may have similar potential in the control of human and porcine cysticercosis. The TEG molecule is characterized by an Nterminal FERM domain and a C-terminal ERM domain which are found in a number of cytoskeletal-associated proteins located at the interface between the plasma membrane and the cytoskeleton and in proteins that interact with lipid membranes. The FERM domain is also postulated to bind to adhesion proteins, in a PIP2-regulated fashion, providing a link between cytoskeletal signals and membrane dynamics. Thus TEG protein may play a role in tegument function and interaction with the host.

Molecular and biochemical parasitology, 2011

The American journal of medicine, 2014

PloS one, 2014

Screen media usage, sleep time and socio-demographic features are related to adolescents' academi... more Screen media usage, sleep time and socio-demographic features are related to adolescents' academic performance, but interrelations are little explored. This paper describes these interrelations and behavioral profiles clustered in low and high academic performance. A nationally representative sample of 3,095 Spanish adolescents, aged 12 to 18, was surveyed on 15 variables linked to the purpose of the study. A Self-Organizing Maps analysis established non-linear interrelationships among these variables and identified behavior patterns in subsequent cluster analyses. Topological interrelationships established from the 15 emerging maps indicated that boys used more passive videogames and computers for playing than girls, who tended to use mobile phones to communicate with others. Adolescents with the highest academic performance were the youngest. They slept more and spent less time using sedentary screen media when compared to those with the lowest performance, and they also showed topological relationships with higher socioeconomic status adolescents. Cluster 1 grouped boys who spent more than 5.5 hours daily using sedentary screen media. Their academic performance was low and they slept an average of 8 hours daily. Cluster 2 gathered girls with an excellent academic performance, who slept nearly 9 hours per day, and devoted less time daily to sedentary screen media. Academic performance was directly related to sleep time and socioeconomic status, but inversely related to overall sedentary screen media usage. Profiles from the two clusters were strongly differentiated by gender, age, sedentary screen media usage, sleep time and academic achievement. Girls with the highest academic results had a medium socioeconomic status in Cluster 2. Findings may contribute to establishing recommendations about the timing and duration of screen media usage in adolescents and appropriate sleep time needed to successfully meet the demands of school academics and to improve interventions targeting to affect behavioral change.

Genome announcements, 2014

Here, we present a 10.7-Mb high-quality draft genome of this parasite close to chromosome resolut... more Here, we present a 10.7-Mb high-quality draft genome of this parasite close to chromosome resolution that will enable comparative genome analyses and synteny studies among related parasites.

Ibis, 1987

The behaviour of five broods of radio-tagged Spanish Imperial Eagles Aquila heliaca adalberti was... more The behaviour of five broods of radio-tagged Spanish Imperial Eagles Aquila heliaca adalberti was studied in Doñana National Park, Spain during the post-fledging period. The distance between perching sites and nest, the mean flight duration and distance, the percentage of time spent flying and the home range all increased exponentially with age. As the young got older, the parents spent less time in their vicinity. Young were not seen hunting, but depended on their parents for food. They begged and chased their parents throughout the post-fledging period, with higher intensity at the end. Nevertheless, the adults became progressively more reluctant to feed them, as reflected in the decrease in feeding frequency and in the number of approaching flights towards the young. At the end of the post-fledging period, adults often performed aerial displays and frequently chased their offspring. The age of independence of the different young studied varied between 123 and 145 days. The correlations between individual independence and the dates when the young were last fed by their parents, and when the highest intensity of parental aggressive behaviour occurred, were higher than correlations with the variables related to the maturation of flying. Therefore, it is suggested that parental ‘meanness' and aggressive behaviour may be the factors determining the date of juvenile independence and dispersal from the home territory.

Biological Conservation, 2006

We studied the factors that led to brood reduction in 1192 nest/years of 143 territories of the S... more We studied the factors that led to brood reduction in 1192 nest/years of 143 territories of the Spanish imperial eagle during the period 1988–2003 and we carried out an innovative supplementary feeding programme in perches near nests in order to mitigate nestling mortality and improve fledging rate. Chick mortality affected 9.3% of hatchlings and 13.9% of the nests monitored. Sibling aggression was the most important factor in brood reduction (54.8% mortality of chicks in the nest), and supplementary feeding limited the process of sibling aggression. In addition, we compared the fledging rate in nests with supplementary food to that of non-supplemented control nests. Supplementary food increased the number of fledglings per brood (1.56 vs 0.72 in the control nests). This increase was repeated in subadult pairs (1.57 vs 0.53 in the control nests) and occurred both in high-quality territories (2.32 vs 1.36) and in low-quality territories (1.35 vs 0.54). Our results also suggest that supplementary feeding does not appear to have any effect on the provisioning rate of either males or females or on the wild prey. Food supplementation led to the recovery of breeding success after a period of loss due to a reduction of prey as a consequence of viral haemorrhagic disease. We conclude that the Spanish imperial eagle’s breeding output is food-limited during the nestling period and that food taken to the nest regulates sibling aggression. Supplemental feeding when food is scarce, or under emergency conditions, can be considered a good management tool for the conservation of this endangered species.

Parasitology, 2009

The taxonomic status of Echinococcus, an important zoonotic cestode genus, has remained controver... more The taxonomic status of Echinococcus, an important zoonotic cestode genus, has remained controversial, despite numerous attempts to revise it. Although mitochondrial DNA (mtDNA) has been the source of markers of choice for reconstructing the phylogeny of the genus, results derived from mtDNA have led to significant inconsistencies with earlier species classifications based on phenotypic analysis. Here, we used nuclear DNA markers to test the phylogenic relationships of members of the genus Echinococcus. The analysis of sequence data for 5 nuclear genes revealed a significantly different phylogeny for Echinococcus from that proposed on the basis of mitochondrial DNA sequence data, but was in agreement with earlier species classifications. The most notable results from the nuclear phylogeny were (1) E. multilocularis was placed as basal taxon, (2) all genotypes of Echinococcus granulosus grouped as a monophyletic entity, and (3) genotypes G8 and G10 clustered together. We conclude that the analysis of nuclear DNA data provides a more reliable means of inferring phylogenetic relationships within Echinococcus than mtDNA and suggest that mtDNA should not be used as the sole source of markers in future studies where the goal is to reconstruct a phylogeny that does not only reflect a maternal lineage, but aims to describe the evolutionary history at species level or higher.

Environmental Toxicology and Chemistry, 2007

We evaluated temporal and regional trends of organochlorine (OC) pesticide (including polychlorin... more We evaluated temporal and regional trends of organochlorine (OC) pesticide (including polychlorinated biphenyl [PCB]) levels in eggs of the Spanish Imperial Eagle (Aquila adalberti) collected in Spain between 1972 and 2003. Levels of p,pЈdichlorodiphenyldichloroethylene (DDE) and PCBs varied significantly ( p ϭ 0.022) among regions (central, western, and Doñana), being higher in Doñana than in the central and western populations (DDE: 1.64 Ϯ 5.56, 0.816 Ϯ 1.70, and 1.1 Ϯ 2.66 g/g, respectively; PCBs: 1.189 Ϯ 5.0, 0.517 Ϯ 1.55, and 0.578 Ϯ 1.75 g/g, respectively). Levels of DDE decreased with time, but a significant interaction was observed between region and time. In Doñana, egg volume and breadth as well as Ratcliffe Index were significantly lower after DDT use ( p ϭ 0.0018) than during the pre-DDT period ( p ϭ 0.0018); eggs were significantly smaller overall than in the other two regions ( p ϭ 0.04) and were smaller when DDE levels increased, even when controlling for regional differences ( p ϭ 0.04). Productivity in Doñana was significantly lower than in the other regions ( p Ͻ 0.001). Clutch size in Doñana varied according to DDE concentrations ( p ϭ 0.01), with the highest DDE concentrations found in clutches consisting of one egg. When considering eggs with DDE levels greater than 3.5 g/g, a significant effect of DDE on fertility was found ( p ϭ 0.03). Clutches with DDE levels greater than 4.0 g/g had a higher probability of hatching failure ( p ϭ 0.07) and produced fewer fledglings ( p ϭ 0.03). If we consider 3.5 g/g as the lowest-observable-adverse-effect level, the proportion of sampled clutches that exceeded that level in Doñana (29%) was significantly higher than in other regions ( p Ͻ 0.001). These eggs showed a mean percentage of thinning of 16.72%. Contamination by OCs, mainly DDE, could explain, at least in part, the low productivity of the Spanish Imperial Eagles in Doñana.

Antimicrobial Agents and Chemotherapy, 2003

In order to characterize the impact of genetic polymorphisms on the susceptibility of subtype C s... more In order to characterize the impact of genetic polymorphisms on the susceptibility of subtype C strains of human immunodeficiency virus type 1 to protease inhibitors (PIs), a subtype B protease that originated from an infectious clone was modified through site-directed mutagenesis to include the amino acid residue signatures of subtype C viruses (I15V, M36I, R41K, H69K, L89 M) with (clone C6) or without (clone C5) an I93L polymorphism present as a molecular signature of the worldwide subtype C protease. Their susceptibilities to commercially available PIs were measured by a recombinant virus phenotyping assay. We could not detect any differences in the 50% inhibitory concentration (IC 50 s) of amprenavir, indinavir, ritonavir, saquinavir, and nelfinavir for the clones analyzed. However, we did observe hypersusceptibility to lopinavir solely in clone C6, which includes the I93L substitution (a 2.6-fold decrease in the IC 50 compared to that for the subtype B reference strain). The same phenotypic behavior was observed for 11 Brazilian and South African clinical isolates tested, in which only subtype C isolates carrying the I93L mutation presented significant hypersusceptibility to lopinavir.

Bird Conservation International, 2008

The distribution and abundance of Spanish Imperial Eagle Aquila adalberti populations between 197... more The distribution and abundance of Spanish Imperial Eagle Aquila adalberti populations between 1974 and 2004 were determined using information from national censuses. Its breeding area occupies the south-western quadrant of the Iberian Peninsula (Spain and Portugal) and is composed of 13 nuclei and 5 subpopulations. Since 1974, population levels in all nuclei, except the one in Doñ ana, have expanded. The non-breeding dispersion area, according to sightings of juvenile and immature individuals in quadrants of 10 x 10 km, coincided with that of the breeding area. Bibliographical information showed that halfway through the 19 th century the Spanish Imperial Eagle was considered abundant, at least locally; and most cited breeding areas were in relatively human-occupied plains. Towards the end of the 19 th century the population became scarce; remaining so for most of the 20 th century, with remote mountain ranges being the most cited breeding habitats. The comparison between the data from the first census, in 1974, that located 38 territorial pairs, and the 2004 census that located 198 pairs, shows that: 1) percentages of pairs in plains have increased, while those in mountains have decreased; 2) the trophic quality of the habitat, based on rabbit abundance, has decreased, and 3) numbers of nests in both protected areas and on private ground have increased significantly. The type of land ownership did not seem to affect breeding performance. Populations have increased more outside protected areas than within, despite the availability of potential habitat. In the past century, legal protection and attitude changes towards this eagle seem to have been influential in preventing its extinction. At present, habitat management seems also to be an important factor in its continuing recovery.