A polymorphic microsatellite from the Squalius alburnoides complex (Osteichthyes, Cyprinidae) cloned by serendipity can be useful in genetic analysis of polyploids

A new microsatellite locus (SAS1) for Squalius alburnoides was obtained through cloning by serendipity. The possible usefulness of this new species-specific microsatellite in genetic studies of this hybrid-species complex, was explored. The polymorphism exhibited by SAS1 microsatellite is an important addition to the set of microsatellites previously used in genetic studies in S. alburnoides complex, that mostly relied in markers described for other species. Moreover, the SAS1 microsatellite could be used to identify the parental genomes of the complex, complementing other methods recently described for the same purpose.

Interaction of Mesoporous Silica Nanoparticles with Human Red Blood Cell Membranes: Size and Surface Effects

The interactions of mesoporous silica nanoparticles (MSNs) of different particle sizes and surface properties with human red blood cell (RBC) membranes were investigated by membrane filtration, flow cytometry, and various microscopic techniques. Small MCM-41-type MSNs (∼100 nm) were found to adsorb to the surface of RBCs without disturbing the membrane or morphology. In contrast, adsorption of large SBA-15-type MSNs (∼600 nm) to RBCs induced a strong local membrane deformation leading to spiculation of RBCs, internalization of the particles, and eventual hemolysis. In addition, the relationship between the degree of MSN surface functionalization and the degree of its interaction with RBC, as well as the effect of RBC−MSN interaction on cellular deformability, were investigated. The results presented here provide a better understanding of the mechanisms of RBC−MSN interaction and the hemolytic activity of MSNs and will assist in the rational design of hemocompatible MSNs for intravenous drug delivery and in vivo imaging

Silica Materials for Medical Applications

The two main applications of silica-based materials in medicine and biotechnology, i.e. for bone-repairing devices and for drug delivery systems, are presented and discussed. The influence of the structure and chemical composition in the final characteristics and properties of every silica-based material is also shown as a function of the both applications presented. The adequate combination of the synthesis techniques, template systems and additives leads to the development of materials that merge the bioactive behavior with the drug carrier ability. These systems could be excellent candidates as materials for the development of devices for tissue engineering

Leuciscus (Pisces, Cyprinidae) karyotypes: Transect of Portuguese populations

The presently described Iberian chubs - Leuciscus carolitertii and L. pyrenaicus - sampled throughout their distribution ranges in Portugal were cytogenetically analyzed. Their chromosome numbers were consistently 2n = 50, except for two specimens of L. carolitertii, which exhibited a supernumerary chromosome in some of the metaphases. The karyotypes were found to be highly typical for other Leuciscus taxa, as well as for European leuciscine cyprinids: the chromosome sets are dominated by metacentric and submetacentric elements with a reduced number of acrocentric pairs (three to four); the largest pair of the complements belongs typically to this latter category. The chubs from northern drainages, assignable to L. carolitertii, have apparently a more stable karyotype structure (12M:30S:8A) than the chubs from L. pyrenaicus, which have 12M:32S:6A, but may exhibit in the most southern river basins (Guadiana, Mira, Aljezur, Bordeira and Arade) more variable karyotypes. Besides, these data support the very recent discovery of two genetically distinct Leuciscus taxa in this region of the Iberian Peninsula, suggesting the stochastic fixation of structural chromosome rearrangements in these small and isolated drainages, which may be affected by bottlenecks due to significant variations in hydrological regimes. The NORs were apparently located in one small submetacentric pair of chromosomes and the presence of a heteromorphic sex chromosome system of the ZW/ZZ type was also evidenced for the Iberian endemic chubs.<br>A análise citogenética dos dois endemismos de Leuciscus atualmente descritos na Península Ibérica foi efetuada em amostras obtidas ao longo da sua área de distribuição. Apresentaram um valor diplóide de 2n = 50, com exceção de dois exemplares de L. carolitertii, os quais exibiam um cromossomo supranumerário em algumas metáfases. Caracterizaram-se por um padrão cariológico idêntico ao dos restantes táxons do mesmo gênero, igualmente partilhado pelos Leuciscinae europeus: um elevado número de cromossomos metacêntricos e submetacêntricos e um número reduzido de acrocêntricos (três a quatro pares), incluindo-se neste último grupo o maior par do complemento. As NORs localizaram-se tipicamente num par de submetacêntricos de reduzidas dimensões, existindo também evidências de um sistema cromossômico de determinação sexual do tipo ZW/ZZ. Porém, os espécimes do norte, L. carolitertii, aparentaram possuir um cariótipo mais estável em termos estruturais (12M:30S:8A) do que os do sul, pertencentes a L. pyrenaicus (12M:32S:6A). Esta espécie exibiu, nas suas populações mais meridionais que se localizam nas bacias do Mira, Aljezur, Bordeira e Arade, alterações da referida fórmula cromossômica, fato que vem em apoio da recente descoberta de dois taxóns de Leuciscus geneticamente diferenciados no sul da Península Ibérica, sugerindo a fixação de rearranjos cromossômicos estruturais nestas pequenas e isoladas bacias hidrográficas, com grandes variações dos seus regimes hidrológicos produzindo os chamados" efeitos de gargalo"