Method for histological preparation of bone sections containing titanium implants

A thin sectioning technique involving hand grinding has been developed to produce 20-40-microns-thick sections of bone-titanium implant sites. Components include: 1) surface staining of sections prior to mounting on slides so bone labels (oxytetracycline-HCl and 2,4-bis(N,N-dicarbomethyl)aminomethylfluorescein (DCAF] can be seen in sections viewed with transmitted light, 2) a pneumatic sample press for bonding sections to slides with a thin, uniform glue line and without trapped air bubbles, and 3) bonding methyl methacrylate embedded sections to clear acrylic slides with methyl methacrylate monomer to provide enhanced bond strength and grinding properties compared to those obtainable with glass slides. Sample cracking and distortion is minimized and the tissue-implant interface can be kept intact. The expense of start-up equipment for this technique is minimal.     

Role of the tubulin-microtubule system in lymphocyte activation

The role of the tubulin-microtubule system was examined in human peripheral blood leukocytes after activation with phytohemagglutinin (PHA). Soluble tubulin and microtubules were measured with a [(3)H]colchicine-binding assay. It was found that the tubulin content of PHA-activated lymphocytes was consistently increased relative to total protein content after 36 h of culture. There was no increase in the proportion of total tubulin synthesis which was present as microtubules at 36 h. Nevertheless, as a result of increased tubulin synthesis, there was a two-to three-fold increase in total microtubular mass. Colchicine, which disrupts microtubles, was used to assess the role of microtubule assembly in the sequence of events which follow lymphocyte activation, namely lymphokine release, protein synthesis, RNA synthesis, and DNA synthesis. Colchicine consistently inhibited DNA synthesis but did not inhibit release of the lymphokine, osteoclast activating factor (OAF). Protein and RNA syntheses were inhibited much less than DNA synthesis. The fact that some effects of PHA on lymphocytes appear to require intact microtubules and at least one does not suggest that the microtubule dependent step in PHA-stimulated lymphocyte activation occurs at a stage after propagation of the signal from the membrane to the cell interior.     

Macroevolutionary insights into sedges (Carex: Cyperaceae): The effects of rapid chromosome number evolution on lineage diversification

Changes in holocentric chromosome number due to fission and fusion have direct and immediate effects on genome structure and recombination rates. These, in turn, may influence ecology and evolutionary trajectories profoundly. Sedges of the genus Carex (Cyperaceae) comprise ca. 2000 species with holocentric chromosomes. The genus exhibits a phenomenal range in the chromosome number (2n = 10 − 132) with almost not polyploidy. In this study, we integrated the most comprehensive cytogenetic and phylogenetic data for sedges with associated climatic and morphological data to investigate the hypothesis that high recombination rates are selected when evolutionary innovation is required, using chromosome number evolution as a proxy for recombination rate. We evaluated Ornstein–Uhlenbeck models to infer shifts in chromosome number equilibrium and selective regime. We also tested the relationship between chromosome number and diversification rates. Our analyses demonstrate significant correlations between morphology and climatic niche and chromosome number in Carex. Nevertheless, the amount of chromosomal variation that we are able to explain is very small. We recognized a large number of shifts in mean chromosome number, but a significantly lower number in climatic niche and morphology. We also detected a peak in diversification rates near intermediate recombination rates. In combination, these analyses point toward the importance of chromosome evolution to the evolutionary history of Carex. Our work suggests that the effect of chromosome evolution on recombination rates, not just on reproductive isolation, may be central to the evolutionary history of sedges.     

Geographical vs. ecological diversification in Carex section Phacocystis (Cyperaceae): Patterns hidden behind a twisted taxonomy

Carex section Phacocystis (Cyperaceae) is one of the most diverse and taxonomically complex groups of sedges (between 116 and 147 species), with a worldwide distribution in a wide array of biomes. It has a very complicated taxonomic history, with numerous disagreements among different treatments. We studied the biogeography and niche evolution in a phylogenetic framework to unveil the relative contribution of geographical and ecological drivers to diversification of the group. We used a large species sampling of the section (82% of extant species) to build a phylogeny based on four DNA regions, constrained with a phylogenomic HybSeq tree and dated with six fossil calibrations. Our phylogenetic results recovered section Phacocystis s.s. (core Phacocystis) as sister to section Praelongae. Ancestral area reconstruction points toward the N Pacific as the cradle for the crown diversification of section Phacocystis during the Middle Miocene. Wide distributions were recurrently inferred across deep nodes. Large Northern Hemisphere lineages with geographical congruence were retrieved, pointing toward the importance of allopatric divergence at deep phylogenetic levels, whereas within-area speciation emerges as the predominant pattern at shallow phylogenetic level. The Southern Hemisphere (Neotropics, SW Pacific) was colonized several times from the Northern Hemisphere. The global expansion of Carex section Phacocystis did not entail major ecological changes along the inner branches of the phylogeny. Nevertheless, ecological differentiation seems to gain importance toward recent times.     

Artificial vision with wirelessly powered subretinal electronic implant alpha-IMS

This study aims at substituting the essential functions of photoreceptors in patients who are blind owing to untreatable forms of hereditary retinal degenerations. A microelectronic neuroprosthetic device, powered via transdermal inductive transmission, carrying 1500 independent microphotodiode-amplifier-electrode elements on a 9 mm² chip, was subretinally implanted in nine blind patients. Light perception (8/9), light localization (7/9), motion detection (5/9, angular speed up to 35 deg s⁻¹), grating acuity measurement (6/9, up to 3.3 cycles per degree) and visual acuity measurement with Landolt C-rings (2/9) up to Snellen visual acuity of 20/546 (corresponding to decimal 0.037 or corresponding to 1.43 logMAR (minimum angle of resolution)) were restored via the subretinal implant. Additionally, the identification, localization and discrimination of objects improved significantly (n = 8; p < 0.05 for each subtest) in repeated tests over a nine-month period. Three subjects were able to read letters spontaneously and one subject was able to read letters after training in an alternative-force choice test. Five subjects reported implant-mediated visual perceptions in daily life within a field of 15° of visual angle. Control tests were performed each time with the implant''s power source switched off. These data show that subretinal implants can restore visual functions that are useful for daily life.     

Hybridization and divergence in multi‐species oak (Quercus) communities

Oaks (Quercus: Fagaceae) commonly interbreed yet retain their morphological, genetic and ecological distinctiveness. Post‐zygotic isolation mechanisms, such as ecologically dependent selection on adaptive loci, may therefore limit introgression. To test this hypothesis, we quantified hybridization and genetic divergence across the contact zone of four red oaks (Quercus section Lobatae) in the Great Lakes region of North America using a suite of 259 amplified fragment length polymorphisms and 27 genic and genomic microsatellite markers. First, we identified hybrids using genetic structure analysis and confirmed the reliability of our assignments via simulations. Then, we identified candidate loci for species maintenance with three complementary tests for selection and obtained partial gene sequences linked to an outlier locus and three other loci. We detected evidence of recent hybridization among all species and considerable gene flow between Q. ellipsoidalis and Q. velutina. Overall, c. 20% of Q. velutina had recent ancestry from Q. ellipsoidalis, whereas nearly 30% of Q. ellipsoidalis had a Q. velutina ancestor. Most loci were negligibly to weakly differentiated among species, but two gene‐linked microsatellites deviated significantly from neutral expectations in multiple, complementary outlier tests. Both outlier loci were located in the same 15‐cM bin on an existing Q. robur linkage map, a region under divergent selection in other oak species. Adaptive loci in this highly differentiated genomic region may contribute to ecological divergence among species and limit introgression.     

Alcoholism is associated with GALR3 but not two other galanin receptor genes

The neuropeptide galanin is widely expressed in the periphery and the central nervous system and mediates diverse physiological processes and behaviors including alcohol abuse, depression and anxiety. Four genes encoding galanin and its receptors have been identified (GAL, GALR1, GALR2 and GALR3). Recently we found that GAL haplotypes were associated with alcoholism, raising the possibility that genetic variation in GALR1, GALR2 and GALR3 might also alter alcoholism risk. Tag single nucleotide polymorphisms (SNPs) were identified by genotyping SNP panels in controls from five populations. For the association study with alcoholism, six GALR1, four GALR2 and four GALR3 SNPs were genotyped in a large cohort of Finnish alcoholics and non-alcoholics. GALR3 showed a significant association with alcoholism that was driven by one SNP (rs3,091,367). Moreover, the combination of the GALR3 rs3,091,367 risk allele and GAL risk haplotypes led to a modestly increased odds ratio (OR) for alcoholism (2.4) as compared with the effect of either GAL (1.9) or GALR3 alone (1.4). Likewise, the combination of the GALR3 and GAL risk diplotypes led to an increased OR for alcoholism (4.6) as compared with the effect of either GAL (2.0) or GALR3 alone (1.6). There was no effect of GALR1 or GALR2 on alcoholism risk. This evidence suggests that GALR3 mediates the alcoholism-related actions of galanin.     

Geographical variation in fecundity and reproductive investment of Loxopagurus loxochelis (Decapoda: Anomura: Diogenidae) along the south-eastern coast of Brazil

We aimed to study the fecundity and reproductive investment of Loxopagurus loxochelis under different environmental conditions. In total, 67 ovigerous females were analyzed, 20 from Macaé, 26 from Ubatuba and 21 from Cananéia. The cephalothoracic shield length, fecundity and reproductive investment (Ubatuba 10.2%, Macaé 8.9% and Cananéia 7.5%) were different among the regions (ANCOVA, p < 0.05), caused by different abiotic resources and environmental characteristics found in each sampling region. Cananéia had the smallest individuals and low availability of adequate shells to hermit crabs, a condition that may have affected the growth and reproduction of the animals. Macaé has a continuous transport of nutrients such as nitrogen and phosphorus to the surface promoted by the Cabo Frio Upwelling zone, which may be a favourable condition for plankton production and, consequently, the extended ‘match/mismatch’ adjustment of spawning females of L. loxochelis. We propose that the highest reproductive investment on the Ubatuba coast is a consequence of regional environmental scenarios of waters colder than the Cananéia region, i.e. females concentrate more energy to reproduce seasonally. Thus, we proved that patterns of L. loxochelis’ reproduction can change on a regional scale according to the local condition of shell supply and water temperature.