Diet diversity and the risk of laryngeal cancer: a case-control study from Italy and Switzerland.

Diet diversity (defined as the number of different foods consumed) has been considered an indicator of a healthy diet, and favorably related to the risk of several digestive tract cancers. We analyzed the relation between diet diversity and the risk of laryngeal cancer using data from a case-control study carried out between 1992 and 2000 in Italy and Switzerland. The subjects of the study were 527 patients with histologically confirmed incident cancers of the larynx and 1297 patients admitted for acute, non-neoplastic diseases, unrelated to tobacco or alcohol consumption. Total diversity was computed as the number of different foods (overall and within four food groups, i.e., vegetables, fruit, meat, and cereals) consumed at least once per week. A significant inverse association was observed for vegetable diversity (OR=0.41, 95% CI: 0.28-0.59, for the highest versus the lowest quartile) and fruit diversity (OR=0.40, 95% CI: 0.27-0.59). Conversely, a direct association was found for meat diversity (OR=1.67, 95% CI: 1.11-2.50), while no meaningful association was found for total diet and cereal diversity. The results were consistent across strata of age, alcohol drinking and tobacco smoking. This study suggests that a diet not only rich but also varied in fruit and vegetables is related to a decreased risk of laryngeal cancer risk.

Structure and diversity of endoparasitic infracommunities and the trophic level of Pseudoplatystoma corruscans and Schizodon borelli (Osteichthyes) of the high Paraná river

One hundred and ten specimens of Pseudoplatystoma corruscans (Pimelodidae) and 582 specimens of Schizodon borelli (Anostomidae) collected in the high Paraná River were analyzed. On necropsy 74% of P. corruscans were found to be parasitized; proteocephalidean cestodes presented the greatest number. With regard to S. borelli, the percentage of parasitism reached 19.42% and the nematode Cucullanus pinnai was the most abundant. The absence of correlation between the endoparasitic diversity and the standard length of the two host species indicates that each one presents homogeneity in alimentary behaviour during all its life time, permiting the uniform recruitment of the same species of endoparasites during all its ontogenetic development. Independence of diversity values in relation to sex of P. corruscans and S. borelli evidences that the ecological relationships are similar between males and females in these species. Both host's infrapopulations presented a typical overdispersed pattern of distribution with isolationist characteristics.

Diversity of Campylobacter Isolates from Three Activated Sludge Systems

Thermophilic campylobacters were isolated from three sewage plants in Rio de Janeiro, RJ, Brazil and identified. Laboratory analysis of 390 sewage samples showed the presence of 169 thermophilic strains. The results demonstrated that human and animal pathogenic biotypes could be isolated from activated sludge during the initial processing steps. The aeration tank could be considered a barrier to Campylobacter survival. C. jejuni was the prevalent species isolated (40.8%).The most common biotypes were C. jejuni biotype I (21.3%), C. coli biotype I (16%) and C. jejuni biotype II ( 14.8%).

Allelic Diversity at the Merozoite Surface Protein-1 (MSP-1) Locus in Natural Plasmodium falciparum Populations: a Brief Overview

The merozoite surface protein-1 (MSP-1) locus of Plasmodium falciparum codes for a major asexual blood-stage antigen currently proposed as a major malaria vaccine candidate. The protein, however, shows extensive polymorphism, which may compromise its use in sub-unit vaccines. Here we compare the patterns of allelic diversity at the MSP-1 locus in wild isolates from three epidemiologically distinct malaria-endemic areas: the hypoendemic southwestern Brazilian Amazon (n = 54), the mesoendemic southern Vietnam (n = 238) and the holoendemic northern Tanzania (n = 79). Fragments of the variable blocks 2, 4a, 4b and 6 or 10 of this single-copy gene were amplified by the polymerase chain reaction, and 24 MSP-1 gene types were defined as unique combinations of allelic types in each variable block. Ten different MSP-1 types were identified in Brazil, 23 in Vietnam and 13 in Tanzania. The proportion of genetically mixed infections (isolates with parasites carrying more than one MSP-1 version) ranged from 39% in Brazil to 44% in Vietnam and 60% in Tanzania. The vast majority (90%) of the typed parasite populations from Brazil and Tanzania belonged to the same seven most frequent MSP-1 gene types. In contrast, these seven gene types corresponded to only 61% of the typed parasite populations from Vietnam. Non-random associations were found between allelic types in blocks 4a and 6 among Vietnamese isolates, the same pattern being observed in independent studies performed in 1994, 1995 and 1996. These results suggest that MSP-1 is under selective pressure in the local parasite population. Nevertheless, the finding that similar MSP-1 type frequencies were found in 1994 and 1996 argues against the prominence of short-term frequency-dependent immune selection of MSP-1 polymorphisms. Non-random associations between MSP-1 allelic types, however, were not detected among isolates from Brazil and Tanzania. A preliminary analysis of the distribution of MSP-1 gene types per host among isolates from Tanzania, but not among those from Brazil and Vietnam, shows significant deviation from that expected under the null hypothesis of independent distribution of parasites carrying different gene types in the human hosts. Some epidemiological consequences of these findings are discussed

Genetic Diversity in Natural Populations of New World Leishmania

Our results have shown the wide diversity of parasites within New World Leishmania. Biochemical and molecular characterization of species within the genus has revealed that much of the population heterogeneity has a genetic basis. The source of genetic diversity among Leishmania appears to arise from predominantly asexual, clonal reproduction, although occasional bouts of sexual reproduction can not be ruled out. Genetic variation is extensive with some clones widely distributed and others seemingly unique and localized to a particular endemic focus. Epidemiological studies of leishmaniasis has been directed to the ecology and dynamics of transmission of Leishmania species/variants, particularly in localized areas. Future research using molecular techniques should aim to identify and follow Leishmania types in nature and correlate genetic typing with important clinical characteristics such as virulence, pathogenicity, drug resistance and antigenic variation. The epidemiological significance of such variation not only has important implications for the control of the leishmaniases, but would also help to elucidate the evolutionary biology of the causative agents.

Adding diversity to ruthenium (II)-arene anticancer (RAPTA) compounds via click chemistry: the influence of hydrophobic chains

The application of click chemistry to develop libraries of organometallic ruthenium-arene complexes with potential anticancer properties has been investigated. A series of ruthenium-imidazole-triazole complexes, with hydrophobic tails, were prepared from a common precursor via click chemistry. The tail could be attached to the ligand prior to coordination to the ruthenium complex were screened for cytotoxicity in tumourigenic and non-tumourigenic cell lines, and while the compounds were only moderately cytotoxic, good selectivity for tumourigenic cells were abserved.

Diversity of Vibrionaceae bacteria isolated from the haemolymph of the spider crab Maja brachydactyla

Aims: The aim of this study was to characterise and identify vibrios isolated from the haemolymph of apparently healthy adult spider crabs (Maja brachydactyla) wild-caught in the Spanish localities of Galician coast and in the Canary Islands and also from captive animals held at IRTA’s facilities in the Ebro Delta of Catalonia, north-west Spanish Mediterranean coast. Methods and Results: A total of 277 bacterial isolates were obtained, and of these, 171 were characterised with rep-PCR, resulting electrophoretic bands were analysed and clusters formed. Identification of representative strains of each cluster was made by sequencing the 16S rRNA. Samples from animals caught in Galicia and captive at IRTA (around 15–18 C) rendered mostly species belonging to the Splendidus clade (72Æ2 and 76Æ6% respectively), commonly found in cold waters (below 20 C). Higher species diversity was found in the haemolymph of the captive animals. In the warmer Canary Islands waters (around 21 C), the diversity of vibrios is dominated by three clades, Harveyi (Vibrio core group, 39Æ3%), Orientalis (23Æ2%) and Splendidus (21Æ4%) with a species diversity that equals that of the colder captive animals. Conclusions: Differences in the vibrios populations were found in the haemolymph extracted from animals collected from the three localities. Potential new species were found, and their description is under way. Significance and Impact of Study: As with other invertebrates, spider crabs also contain a diverse population of vibrios. These findings should help researchers to diagnose when a crab is infected.

Multilocus sequence analysis reveals the genetic diversity of European fruit tree phytoplasmas and supports the existence of inter-species recombination

The genetic diversity of three temperate fruit tree phytoplasmas ‘Candidatus Phytoplasma prunorum’, ‘Ca. P. mali’ and ‘Ca. P. pyri’ has been established by multilocus sequence analysis. Among the four genetic loci used, the genes imp and aceF distinguished 30 and 24 genotypes, respectively, and showed the highest variability. Percentage of substitution for imp ranged from 50 to 68% according to species. Percentage of substitution varied between 9 and 12% for aceF, whereas it was between 5 and 6% for pnp and secY. In the case of ‘Ca P. prunorum’ the three most prevalent aceF genotypes were detected in both plants and insect vectors, confirming that the prevalent isolates are propagated by insects. The four isolates known to be hypo-virulent had the same aceF sequence, indicating a possible monophyletic origin. Haplotype network reconstructed by eBURST revealed that among the 34 haplotypes of ‘Ca. P. prunorum’, the four hypo-virulent isolates also grouped together in the same clade. Genotyping of some Spanish and Azerbaijanese ‘Ca. P. pyri’ isolates showed that they shared some alleles with ‘Ca. P. prunorum’, supporting for the first time to our knowledge, the existence of inter-species recombination between these two species.

Genetic diversity and genetic exchange in Trypanosoma cruzi: dual drug-resistant "progeny" from episomal transformants

Extensive characterisation of Trypanosoma cruzi by isoenzyme phenotypes has separated the species into three principal zymodeme groups, Z1, Z2 and Z3, and into many individual zymodemes. There is marked diversity within Z2. A strong correlation has been demonstrated between the strain clusters determined by isoenzymes and those obtained using random amplified polymorphic DNA (RAPD) profiles. Polymorphisms in ribosomal RNA genes, in mini-exon genes, and microsatellite fingerprinting indicate the presence of at least two principal T. cruzi genetic lineages. Lineage 1 appears to correspond with Z2 and lineage 2 with Z1. Z1 (lineage 2) is associated with Didelphis. Z2 (lineage 1) may be associated with a primate host. Departures from Hardy-Weinberg equilibrium and linkage disequilibrium indicate that propagation of T. cruzi is predominantly clonal. Nevertheless, two studies show putative homozygotes and heterozygotes circulating sympatrically: the allozyme frequencies for phosphoglucomutase, and hybrid RAPD profiles suggest that genetic exchange may be a current phenomenon in some T. cruzi transmission cycles. We were able to isolate dual drug-resistant T. cruzi biological clones following copassage of putative parents carrying single episomal drug-resistant markers. A multiplex PCR confirmed that dual drug-resistant clones carried both episomal plasmids. Preliminary karyotype analysis suggests that recombination may not be confined to the extranuclear genome.

Minicircle kDNA microheterogeneity in Endotrypanum indicate diversity within this genus

A comparison of kDNA restriction-endonuclease fragment patterns from strains representing selected Endotrypanum zymodemes was done by schizodeme analysis. As the degree of heterogeneity within mini-circles varied among species or strains of Endotrypanum, the fingerprint obtained with each of the restriction enzymes was unique for each of these parasites. The data have revealed that this trypanosomatid genus is much more complex than it was originally thought to be.

Analysis of genetic diversity of Trypanosoma cruzi: an application of riboprinting and gradient gel electrophoresis methods

Analysis of restriction fragment length polymorphism (RFLP) profiles derived from digestion of polymerase chain reaction (PCR) products of the ribosomal 18S from Trypanosoma cruzi yields a typical `riboprint' profile that can vary intraspecifically. A selection of 21 stocks of T. cruzi and three outgroup taxa: T. rangeli, T. conorhini and Leishmania braziliensis were analysed by riboprinting to assess divergence within and between taxa. T. rangeli, T. conorhini and L. braziliensis could be easily differentiated from each other and from T. cruzi. Phenetic analysis of PCR-RFLP profiles indicated that, with one or two exceptions, stocks of T. cruzi could be broadly partitioned into two groups that formally corresponded to T. cruzi I and T. cruzi II respectively. To test if ribosomal 18S sequences were homogeneous within each taxon, gradient gel electrophoresis methods were employed utilising either chemical or temperature gradients. Upon interpretation of the melting profiles of riboprints and a section of the 18S independently amplified by PCR, there would appear to be at least two divergent 18S types present within T. cruzi. Heterogeneity within copies of the ribosomal 18S within a single genome has therefore been demonstrated and interestingly, this dimorphic arrangement was also present in the outgroup taxa. Presumably the ancestral duplicative event that led to the divergent 18S types preceded that of speciation within this group. These divergent 18S paralogues may have, or had, different functional pressures or rates of molecular evolution. Whether or not these divergent types are equally transcriptionally active throughout the life cycle, remain to be assessed.

Mosquitocidal bacterial toxins: diversity, mode of action and resistance phenomena

Bacteria active against dipteran larvae (mosquitoes and black flies) include a wide variety of Bacillus thuringiensis and B. sphaericus strains, as well as isolates of Brevibacillus laterosporus and Clostridium bifermentans. All display different spectra and levels of activity correlated with the nature of the toxins, mainly produced during the sporulation process. This paper describes the structure and mode of action of the main mosquitocidal toxins, in relationship with their potential use in mosquito and/or black fly larvae control. Investigations with laboratory and field colonies of mosquitoes that have become highly resistant to the B. sphaericus Bin toxin have shown that several mechanisms of resistance are involved, some affecting the toxin/receptor binding step, others unknown.

Law and the practise of principle in diverse societies

Projecte de recerca elaborat a partir d’una estada a la London School of Economics and Political Science, United Kingdom, entre 2007 i 2009. L’objecte principal del projecte ha estat analitzar les implicacions jurídico-polítiques i institucionals d’una teoria de la justícia i la igualtat liberals aplicada a societats multiculturals amb un marcat predomini de la diversitat cultural. L’anàlisi desenvolupa una línia d'investigació interdisciplinar - entre el dret i la teoria política - iniciada en una tesis doctoral sobre multiculturalisme i drets de les minories culturals (UPF, 2000) que va culminar en la publicació de Group Rights as Human Rights (Springer, 2006). La recerca adopta com a punt de partida les conclusions de l'esmentada obra, en especial, la rellevància del reconeixement de drets col•lectius; tanmateix, el tipus de qüestions plantejades, l’enfoc i la metodologia emprades són substancialment diferents. En concret, s'adrecen preguntes específiques sobre el model i aspiracions del constitucionalisme democràtic i el paper del dret en contextos multiculturals. També s’atorga un pes central a la dimensió institucional dels models de gestió de la diversitat que s’analitzen, prioritzant un enfocament comparatiu a partir de l’estudi de controvèrsies concretes. L’objectiu és superar algunes limitacions importants de la literatura actual, com ara la tendència a examinar en abstracte la compatibilitat de determinades demandes amb el constitucionalisme democràtic, sense abordar el funcionament d'estratègies de gestió de la diversitat cultural emprades en contextos concrets. Els treballs producte d'aquest projecte articulen les línies bàsiques d’un model pluralista, basat en principis més que en regles, que desafia els plantejaments dominants actualment. Aquest model es caracteritza pel compromís amb la legitimitat i igualtat comparatives, rebutjant el paternalisme i les visions liberals típiques sobre el paper de la regulació. La presumpció de l’“standing” moral dels grups identitaris és fonamental per tal de considerar-los interlocutors vàlids amb interessos genuïns. També s’argumenta que la integració social en contextos multiculturals no depèn tant de l’eliminació del conflicte sinó, sobre tot, d’una gestió eficient que eviti abusos de poder sistemàtics. El model defensa el rol del dret en la institucionalització del diàleg intercultural, però admet que el diàleg no necessàriament condueix a l’acord o a una estructura reguladora coherent i uniforme. Les aspiracions del ordre jurídic pluralista són més modestes: afavorir la negociació i resolució en cada conflicte, malgrat la persistència de la fragmentació i la provisionalitat dels acords. La manca d'un marc regulador comú esdevé una virtut en la mesura que permet la interacció de diferents subordres; una interacció governada per una multiplicitat de regles no necessàriament harmòniques. Els avantatges i problemes d’aquest model s'analitzen a partir de l'anàlisi de l’estructura fragmentària de l'ordre jurídic internacional i del règim Europeu de drets humans.