Relative influence of habitat heterogeneity, climate, human disturbance, and spatial structure on vertebrate species richness in Spain

Many factors affect the distribution of species richness. This study examines the relative influence of habitat heterogeneity, climate, human disturbance, and spatial structure on the species-richness distribution of terrestrial vertebrates (amphibians, reptiles, birds and mammals) in mainland Spain. The results indicate that spatial structure and environment exert similar influences on species richness. For all four taxa, species richness increases southward and northward, being lower in the center of the country, when controlled for other variables. This may be the result of a peninsular effect, as found in other studies, and reflect the importance of historical events on species richness in the Iberian Peninsula. Climate is more important than habitat heterogeneity in determining species richness. Temperature is positively correlated with amphibian, reptile, and bird species richness, while mammalian species richness is highest at intermediate temperatures. This effect is stronger in ectotherms than among endotherms, perhaps reflecting physiological differences. Precipitation positively correlates with bird and mammalian species richness, but has no effect on ectotherm species richness. Amphibian species richness increases with altitudinal range, and bird species richness with habitat diversity. Human population density is positively correlated with bird and mammalian species richness, but does not affect ectotherm species richness, while amphibian and bird species richness is highest at moderate levels of human land alteration (farmland). However, unexplained variance remains, and we discuss that the effects of environmental variables on species richness may vary geographically, causing different effects to be obscured on a national scale, diminishing the explanatory power of environmental variables.     

Hybridization-based antibody cDNA recovery for the production of recombinant antibodies identified by repertoire sequencing

High-throughput sequencing of the antibody repertoire is enabling a thorough analysis of B cell diversity and clonal selection, which may improve the novel antibody discovery process. Theoretically, an adequate bioinformatic analysis could allow identification of candidate antigen-specific antibodies, requiring their recombinant production for experimental validation of their specificity. Gene synthesis is commonly used for the generation of recombinant antibodies identified in silico. Novel strategies that bypass gene synthesis could offer more accessible antibody identification and validation alternatives. We developed a hybridization-based recovery strategy that targets the complementarity-determining region 3 (CDRH3) for the enrichment of cDNA of candidate antigen-specific antibody sequences. Ten clonal groups of interest were identified through bioinformatic analysis of the heavy chain antibody repertoire of mice immunized with hen egg white lysozyme (HEL). cDNA from eight of the targeted clonal groups was recovered efficiently, leading to the generation of recombinant antibodies. One representative heavy chain sequence from each clonal group recovered was paired with previously reported anti-HEL light chains to generate full antibodies, later tested for HEL-binding capacity. The recovery process proposed represents a simple and scalable molecular strategy that could enhance antibody identification and specificity assessment, enabling a more cost-efficient generation of recombinant antibodies.     

Ripening in papaya fruit is altered by ACC oxidase cosuppression

Papaya (Carica papaya) is a very important crop in many tropical countries but it is highly susceptible to parasitic diseases, physiological disorders, mechanical damage and fruit overripening. Here we report a study on ACC oxidase cosuppression and its effects on papaya fruit ripening. Papaya ACC oxidase was isolated using PCR and embriogenic cells transformed by biolistic using the CaMV 35S promoter to drive the expression of the PCR fragment in sense orientation. Fifty transgenic lines were recovered and 20 of those were grown under field conditions. Southern analysis showed incorporation of the transgene in different copy numbers in the papaya genome. Fruits were evaluated in terms of texture (firmness), colour development, respiration and ethylene production. A sharp reduction in ethylene and CO2 production was detected, whereas softening and colour development of the peel were also altered. Overall, transgenic fruits showed a delay in ripening rate. A reduction in mRNA level for ACC oxidase in transgenic fruit was clearly detectable by northern blot. More studies are necessary before this technology can be used to extend the shelf life of papaya fruit.     

A genetic map of tetraploid <Emphasis Type="Italic">Paspalum notatum</Emphasis> Flügge (bahiagrass) based on single-dose molecular markers

Paspalum notatum Flügge is a warm-season forage grass with mainly diploid (2n = 20) and autotetraploid (2n = 40) representatives. Diploid races reproduce sexually and require crosspollination due to a self-incompatible mating system, while autotetraploids reproduce by aposporous apomixis. The objectives of this work were to develop a genetic linkage map of Paspalum notatum Flügge at the tetraploid level, identify the linkage/s group/s associated with apomixis and carry out a general characterization of its mode of inheritance. A pseudo test-cross F₁ family of 113 individuals segregating for the mode of reproduction was obtained by crossing a synthetic completely sexual tetraploid plant (Q4188) as female parent with a natural aposporous individual (Q4117) as pollen donor. Map construction was based on single-dose markers (SDAFs) segregating from both parents. Two linkage maps (female and male) were constructed. Within each map, homologous groups were assembled by detecting repulsion-phase linked SDAFs. Putative Q4188 and Q4117 homolog groups were identified by mapping shared single dose markers (BSDF). The Q4188 map consisted of 263 markers distributed on 26 co-segregation groups over a total genetic distance of 1.590.6 cM, while the Q4117 map contained 216 loci dispersed on 39 co-segregation groups along 2.265.7 cM, giving an estimated genome coverage of 88% and 83%, respectively. Seven and 12 putative homologous chromosomes were detected within Q4188 and Q4117 maps, respectively. Afterward, ten female and male homologous chromosomes were identified by mapping BSDFs. In the Q4117 map, a single linkage group was associated with apospory. It was characterized by restriction in recombination and preferential chromosome pairing. A BPSD marker mapping within this group allowed the detection of the female homolog and the putative four male groups of the set carrying apospory.     

Wave front migration of endothelial cells in a bone-implant interface

The neo-vascularization of the host site is crucial for the primary fixation and the long-term stability of the bone-implant interface. Our aim was to investigate the progression of endothelial cell population in the first weeks of healing. We proposed a theoretical reactive model to study the role of initial conditions, random motility, haptotaxis and chemotaxis in interactions with fibronectin factors and transforming angiogenic factors. The application of governing equations concerned a canine experimental implant and numerical experiments based upon statistical designs of experiments supported the discussion. We found that chemotaxis due to transforming angiogenic factors was attracting endothelial cells present into the host bone. Haptotaxis conditioned by fibronectin factors favored cells adhesion to the host bone. The combination of diffusive and reactive effects nourished the wave front migration of endothelial cells from the host bone towards the implant. Angiogenesis goes together with new-formed bone formation in clinics, so the similarity of distribution patterns of mineralized tissue observed in-vivo and the spatio-temporal concentration of endothelial cells predicted by the model, tended to support the reliability of our theoretical approach.     

Functional CD169 on Macrophages Mediates Interaction with Dendritic Cells for CD8+ T Cell Cross-Priming

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