Isolation and biochemical characterisation of lipid rafts from Atlantic cod (Gadus morhua) intestinal enterocytes

Lipid rafts are glycosphingolipid/cholesterol-enriched membrane microdomains that have been extensively studied during the past two decades. Our aim was to isolate and perform biochemical characterization of lipid rafts from the intestinal brush border membrane (BBM) of Atlantic cod (Gadus morhua) to confirm their existence in a cold-water species and compare their characteristics with lipid rafts from other species in terms of lipid and protein content. To validate the isolation process, we assayed marker enzymes for subcellular organelles, including alkaline phosphatase (AP) and leucine aminopeptidase (LAP), both well-known marker enzymes for BBM and lipid rafts. All biochemical methods showed enrichment of AP in both the BBM and lipid raft fractions. Proteomic studies were performed by MALDI-TOF mass spectrometry using trypsin digested SDS-PAGE samples. Various proteins were associated with the cod intestinal lipid raft preparation such as aminopeptidase-N, prohibitin, and beta-actin. Lipid analysis with ³¹P NMR and thin layer chromatography on BBMs and lipid rafts samples gave higher content of sphingomyelin than previously reported in the BBM and lower content of phosphatidylcholine. Furthermore, sphingomyelin was highly dominant in the lipid rafts together with cholesterol. The existence of lipid rafts containing previously reported lipid raft characteristics from the cod intestine has, therefore, been confirmed in a ray-finned fish for the first time to the best of our knowledge.     

Applicability of Coriolopsis rigida for Biodegradation of Polycyclic Aromatic Hydrocarbons

Laccase was produced by Coriolopsis rigida using barley bran as substrate in solid-state fermentation (SSF) and also by submerged fermentation (SmF). The best results were obtained in SSF with twice the amount of laccase production. Laccase could be produced from repeated batch cultures of SSF over 30 days. The laccase degraded several polycyclic aromatic hydrocarbons (PAHs) in vivo and in vitro. The addition of an effective mediator, 1-hydroxybenzotriazol (50 µM), during in vitro treatment increased the degradation rate.     

Micropropagation and field performance of Yucca valida

Yucca valida is an important potential source of steroidal saponins closely related to Yucca schidigera, the species that is commercially exploited from the wild as a source of steroidal extracts. Neither of the species has been domesticated mainly because of their slow growth and long life span before harvesting. Here, we report a micropropagation method to generate isogenic or clonal lines for plantation purposes. Seventeen clonal lines were propagated and evaluated over a period of 26 months in an experimental plantation and compared with the performance of plants from seeds. The large variability found between the plants derived from seeds is manifested in the differences observed between the different clonal lines; however, these present a much smaller internal coefficient of variation than the one observed in the population of plants derived from seeds. Some clonal lines perform in a superior manner indicating that a process of selection and cloning can generate lines of fast growing individuals for plantations that can satisfy the demand for these materials without putting a natural resource at risk.     

Self-incompatibility and floral parameters in Hypochaeris sect. Hypochaeris (Asteraceae)

We studied the relationships between self-incompatibility mechanisms and floral parameters in the genus Hypochaeris L. sect. Hypochaeris (consisting of H. glabra, H. radicata, H. arachnoidea, and H. salzmanniana). We assessed at intra- and interspecific levels (1) the self-incompatibility (SI) mechanism and its distribution among populations, (2) the relationship between SI and floral parameters, and (3) the relationship of SI to reproductive success. Hypochaeris salzmanniana is semi-incompatible, H. glabra is self-compatible, and H. arachnoidea and H. radicata are self-incompatible. Floral parameters differed among populations of H. salzmanniana: plants in self-compatible populations had fewer flowers per head, a smaller head diameter on the flower, and a shorter period of anthesis than self-incompatible populations. We also detected this pattern within a semi-compatible population of H. salzmanniana, and these differences were also found between species with different breeding mechanisms. Fruit to flower ratio in natural populations was generally high (>60%) in all species, regardless of breeding system. It is hypothesized that self-compatibility may have arisen through loss of allelic diversity at the S locus due to bottleneck events and genetic drift.     

A regression analysis of q’eqchi’ Maya medicinal plants from southern Belize

A previous study provided a general quantitative analysis of 169 collected medicinal plants used by the Q’eqchi’ Maya healers of southern Belize. This paper is focused on a statistical analysis of this ethnobotanical information using the method developed by Moerman (1991). The residual values obtained from the regression analysis of the Q’eqchi’ medicinal plant species versus the species listed in the checklist of the vascular plants of Belize (Balick, Nee, and Atha, 2001) placed the Piperaceae, the Rubiaceae, and the Asteraceae in the first three ranks, and the Poaceae, the Cyperaceae, and the Orchidaceae in the last three ranks. The results were compared with three northern temperate regions (Kashmir, Korea, and North America) and three southern neotropical regions (Chiapas, Ecuador, and Veracruz). The coefficients of correlation between the checklist of vascular plants of Belize and the other six floras showed, as expected, high values for regions with similar climatic type. Thus, high correlations were determined between the tropical vegetation of Belize and those of Chiapas, Ecuador, and Veracruz. The coefficients were lower with the three temperate floras but still quite high. The same analysis was done with the medicinal plants only and led to much lower coefficients, but once again, the higher results were obtained for Chiapas and Veracruz. In this case, the last rank for Ecuador demonstrated that the selection of plants in traditional medicine by the indigenous people is a complex phenomenon which depends not only on the composition of the flora but also on culture-specific factors.

---

Analyse par Regression des Plantes Médicinales des Mayas Q’eqchi'’ du Sud du Belize

Résumé  Une précédente étude a fourni une analyse quantitative générale de 169 plantes médicinales utilisées par les guérisseurs Maya Q’eqchi’ du sud du Belize. Ce document se concentre sur l’analyse statistique des informations ethnobotaniques selon la méthode développée par Moerman (1991). Les valeurs résiduelles obtenues à partir des analyses de régression des plantes médicinales Q’eqchi’ vis-à-vis des espèces mentionnées dans la liste des plantes vasculaires du Belize (Balick, Nee, et Atha, 2001) ont placé les Piperacées, les Rubiacées et les Asteracées aux trois premières places, et les Poacées, les Cyperacées et les Orchidacées aux trois dernières places. Les résultats ont été comparés avec ceux de trois régions tempérées du nord (Cachemire, Corée, et Amérique du Nord) et de trois régions néotropicales du sud (Chiapas, équateur, et Veracruz). Les coefficients de corrélation entre les plantes listées dans le manuel des plantes vasculaires du Belize et les six autres flores ont montré comme attendu de hautes valeurs pour les régions possédant un type climatique similaire. Ainsi, une haute corrélation a été démontrée entre la végétation tropicale du Belize et celles du Chiapas, de l’équateur, et du Veracruz. Les coefficients étaient plus bas avec les trois régions tempérées mais tout de même passablement élevés. La même analyse a été effectuée avec les plantes médicinales et a mené à des coefficients beaucoup plus bas, mais encore une fois, les résultats les plus élevés ont été obtenus pour le Chiapas et le Veracruz. Dans ce cas, la dernière position de l’équateur a souligné que la sélection des plantes par les indigènes dans la médecine traditionnelle est un phénomène complexe qui dépend non seulement de la composition de la flore mais aussi de facteurs spécifiques à la culture.

     

Multilocus sequence typing method for identification and genotypic classification of pathogenic Leptospira species

Background

Multi-drug resistant Pseudomonas aeruginosa nosocomial infections are increasingly recognized worldwide. In this study, we focused on the virulence of multi-drug resistant clinical strains P. aeruginosa against the intestinal epithelial barrier, since P. aeruginosa can cause lethal sepsis from within the intestinal tract of critically ill and immuno-compromised patients via mechanisms involving disruption of epithelial barrier function.

Methods

We screened consecutively isolated multi-drug resistant P. aeruginosa clinical strains for their ability to disrupt the integrity of human cultured intestinal epithelial cells (Caco-2) and correlated these finding to related virulence phenotypes such as adhesiveness, motility, biofilm formation, and cytotoxicity.

Results

Results demonstrated that the majority of the multi-drug resistant P. aeruginosa clinical strains were attenuated in their ability to disrupt the barrier function of cultured intestinal epithelial cells. Three distinct genotypes were found that displayed an extreme epithelial barrier-disrupting phenotype. These strains were characterized and found to harbor the exoU gene and to display high swimming motility and adhesiveness.

Conclusion

These data suggest that detailed phenotypic analysis of the behavior of multi-drug resistant P. aeruginosa against the intestinal epithelium has the potential to identify strains most likely to place patients at risk for lethal gut-derived sepsis. Surveillance of colonizing strains of P. aeruginosa in critically ill patients beyond antibiotic sensitivity is warranted.     

Abundance and distribution of American beaver, Castor canadensis (Kuhl 1820), in Tierra del Fuego and Navarino islands, Chile

Castor canadensis specimens were imported from Canada and released in the wilderness on the Argentinean part of Tierra del Fuego (TDF) in the year 1946. First studies on the development of the beaver population and subsequent environmental changes were conducted four decades later and indicated a strong expansion of these animals, with negative effects on the forest, especially the dominant Nothofagus sp. Between 1999 and 2001, we investigated the density of the beaver population in the Chilean part of TDF and the southern adjacent island Navarino (NAV). Data were mapped into a geographical information system. The mean colony density was 1.03 (range: 0.15–1.91) and 1.1 per km watercourse for 75% of the area of TDF (mainly south and central region) and the total NAV island, respectively. The average number of individuals estimated per colony was five. Based on these findings, the number of beavers in the Chilean part of TDF and on NAV was estimated at 61,300 individuals. The population is increasing and expanding in the Northern region, with a linear rate of 2.6–6.3 km/year.