Effects of Quantum Fluctuations on the Low-Energy Collective Modes of Two-Dimensional Superfluid Fermi Gases from the BCS to the Bose Limit.

We investigate the effects of quantum fluctuations on the low-energy collective modes of two-dimensional (2D) s-wave Fermi superfluids from the BCS to the Bose limit. We compare our results to recent Bragg scattering experiments in 2D box potentials, with very good agreement. We show that quantum fluctuations in the phase and modulus of the pairing order parameter are absolutely necessary to give physically acceptable chemical potential and dispersion relation of the low-energy collective mode throughout the BCS to Bose evolution. Furthermore, we demonstrate that the dispersion of the collective modes change from concave to convex as interactions are tuned from the BCS to the Bose regime, and never crosses the two-particle continuum, because arbitrarily small attractive interactions produce bound states in two dimensions.

Spermatogonial asynchrony in Tex14 mutant mice lacking intercellular bridges.

The existence of cytoplasmic passages between germ cells and their potential function in the control of the spermatogenic process has long been an intriguing question. Evidence of the important role of such structures, known as intercellular bridges (ICB), in spermatogenesis has been implicated by the failure of spermatogenesis in testis-expressed gene 14 (Tex14) mutant mice, which lack the ICBs, to progress past the pachytene spermatocyte stage. Using these Tex14 mutants, the present study evaluated, for the first time, the behavior and synchrony of the spermatogonial lineage in the absence of ICBs. Our data suggest that the absence of these cytoplasmic connections between cells affects the expansion of the undifferentiated type A (Aundiff) spermatogonia compartment and their transition to A1, resulting in a significant numerical reduction of differentiating A1 spermatogonia, but did not interfere with cell amplification during subsequent mitotic steps of differentiating spermatogonia from A1 through intermediate (In). However, beginning at the type B spermatogonia, the synchrony of differentiation was impaired as some cells showed delayed differentiation compared to their behavior in a normal seminiferous epithelium cycle. Thus although spermatogonial development is able to proceed, in the absence of ICBs in Tex14-/- mutants, the yield of cells, specific steps of differentiation, the synchrony of the cell kinetics, and the subsequent progression in meiosis are quantitatively lower than normal.

Nematic-Orbit Coupling and Nematic Density Waves in Spin-1 Condensates.

We propose the creation of artificial nematic-orbit coupling in spin-1 Bose-Einstein condensates, in analogy with spin-orbit coupling. Using a suitably designed microwave chip, the quadratic Zeeman shift, normally uniform in space, can be made to be spatiotemporally varying, leading to a coupling between spatial and nematic degrees of freedom. A phase diagram is explored where three quantum phases with the nematic order emerge: easy axis, easy plane with single-well structure, and easy plane with double-well structure in momentum space. By including spin-dependent and spin-independent interactions, we also obtain the low energy excitation spectra in these three phases. Last, we show that the nematic-orbit coupling leads to a periodic nematic density modulation in relation to the period λ_{T} of the cosinusoidal quadratic Zeeman term. Our results point to the rich possibilities for manipulation of tensorial degrees of freedom in ultracold gases without requiring Raman lasers, and therefore, obviating light-scattering induced heating.

Contributions of classical and molecular cytogenetic in meiotic analysis and pollen viability for plant breeding.

The analysis of meiotic behavior has been widely used in the study of plants as they provide relevant information about the viability of a species. Meiosis boasts a host of highly conserved events and changes in genes that control these events will give rise to irregularities that can alter the normal course of meiosis and may lead to complete sterility of the plant. The recombination of genes that occur in meiosis is an important event to generate variability and has been important in studies for genetic improvement and to create viable hybrids. The use of fluorescence in situ hybridization and genomic in situ hybridization (GISH) in meiosis allows the localization of specific regions, enables to differentiate genomes in a hybrid, permits to observe the pairing of homoeologous chromosomes, and if there was a recombination between the genomes of progenitor species. Furthermore, the GISH allows us to observe the close relationship between the species involved. This article aims to report over meiosis studies on plants and hybrids, the use and importance of molecular cytogenetic in meiotic analysis and contributions of meiotic analysis in breeding programs.

Establishment of the genomic in situ hybridization (GISH) technique for analysis in interspecific hybrids of Passiflora.

The genomic in situ hybridization (GISH) technique was applied to Passiflora interspecific F1 HD13-133 hybrids (Passiflora sublanceolata x Passiflora foetida) and HD15-101 (Passiflora gardineri x Passiflora gibertii), and the backcrossed hybrids (BC1) HD18-106 and HD18-113 (Passiflora sublanceolata x HD13-133). GISH was performed using genomic probes prepared with the DNA from the paternal genitor, whereas the maternal DNA was used as blocking DNA and employed at various concentrations (20X, 40X, 60X, and 100X) in relation to the probe concentration. At the same time, GISH was applied with the use of simultaneous probes from both genomes, paternal and maternal, that were detected with avidin-FITC and anti-digoxigenin-rhodamine, respectively. Both methodologies allowed the distinguishing of the maternal and paternal genomes, thus confirming the hybrid nature of all the analyzed genotypes. Furthermore, the presence of recombinant chromosomes in BC1 hybrids revealed the occurrence of meiotic recombination in HD13 hybrids. This application of the GISH technique is an important step towards genomic analyses of Passiflora hybrids: it can broaden the phylogenetic and evolutionary studies of the genus and, at the same time, contribute to breeding programs.

Multivariate analysis of backcross progeny of Passiflora L. (Passifloraceae) for pre-breeding genotype selection.

The Ward-MLM procedure was used to evaluate genetic variation in four backcross progenies and in their parents, hybrid F1 HD13 and donor parent Passiflora sublanceolata. Sixteen quantitative descriptors and five qualitative characteristics of relevance to ornamental flower production were assessed. Using the pseudo-F and pseudo-T² criteria, we identified four groups among these plants in two evaluation periods. In both evaluations, the BC1 plants showed greater dissimilarity to their recurrent parent, but showed high genetic similarity with the P. sublanceolata parent. The first two canonical variables produced by the Ward-MLM procedure accounted for over 90% of the variation in both evaluation periods, enabling the representation of diversity through two-dimensional graphics. Groups II and IV were formed in the first assessment period. Groups I and IV formed in the second period and showed plants with selection potential. We found that it was essential to use both qualitative and quantitative variables for this analysis. Assessments of quantitative descriptors indicate that the selection of BC1 plants can be performed in any of the four progenies. Because of the similarities observed for some floral descriptors between BC1 and the P. sublanceolata parent, a second generation backcross was not recommended. However, the selection of BC1 plants for evaluation and direct use as an ornamental cultivar, or as a resource in other breeding programs, can be recommended.

ISSR markers in wild species of Passiflora L. (Passifloraceae) as a tool for taxon selection in ornamental breeding.

Inter simple sequence repeat (ISSR) molecular markers were developed and used to investigate interspecific genetic variation in 25 wild species of Passiflora preserved in an active germplasm bank (BAG-Passifloras); intraspecific diversity was also analyzed in P. cincinnata accessions. Of 31 primers tested, 20 identified polymorphic loci with a total of 331 bands, suggesting high polymorphism in the sample. Interspecific polymorphism was greater than intraspecific polymorphism. This is a common finding in studies of genetic variation using dominant markers. The ISSRs revealed species-specific amplification bands in 11 species; these bands ranged from 200 to 1000 bp, and they will be of use for developing SCAR markers for the identification of germplasm in further studies. The use of Jaccard's similarity coefficient to obtain a dendrogram by the UPGMA clustering method distributed the taxa into five major groups, with differences among grouping with respect to principal coordinate analysis. Despite the high cophenetic correlation coefficient (r = 0.94) of the dendrogram, taxonomic inconsistencies were observed; similar irregularities have been reported previously in studies using dominant markers. Intraspecific analysis of P. cincinnata accessions revealed a larger genetic distance between those from Bahia (P2) and from Minas Gerais (P2), indicating that both accessions have considerable potential as parents in a genetic improvement program for this species.

Molecular analysis of patients suspected of Fragile X Syndrome.

The aim of this study was to validate the molecular genetic diagnosis of patients suspected of Fragile X Syndrome (FXS) in the Laboratory of Human Cytogenetics and Molecular Genetics (LaGene) of the Department of Health of the State of Goiás, using polymerase chain reaction (PCR). Thirty-five patients referred by public health doctors to LaGene, indicating clinical diagnosis of FXS, were selected for this study. Two PCR analyses were performed using different primers, one for screening (PCR-T) and one for the detection of the pre-mutation (PCR-P). The products of both PCRs were subjected to polyacrylamide gel electrophoresis and then coloring. The visualization of amplicons was performed with the aid of an ultraviolet transilluminator. The diagnosis was confirmed in 88% of patients with PCR-T and 100% with PCR-P. The primer used in PCR-P was found to be more sensitive and specific, allowing to identify the mutation in the samples, generating a more conclusive case for FXS, noting that the PCR-T is also required for the pre-classification of patients. Generally, the PCR technique is cheaper and easier to handle; therefore, we suggest the implementation of PCR in the genetics laboratory of the State of Goiás (LaGene) for the diagnosis of FXS.

Modulating effect of low level-laser therapy on fibrosis in the repair process of the tibialis anterior muscle in rats.

The treatment of muscle injuries is a common practice at rehabilitation centers. Low-level laser therapy (LLLT) has demonstrated positive effects regarding the modulation of the inflammatory response, the enhancement of the tissue repair process and the prevention of fibrosis. The aim of the present study was to evaluate the effects of LLLT on morphological aspects of muscle tissue, collagen remodeling and activity of matrix metalloproteinase 2 (MMP-2) in rat skeletal muscle following acute injury. Wistar rats were divided into five groups: (1) control group (n = 10), (2) sham group (n = 10), (3) LLLT group (n = 30), (4) non-treated injury group (n = 30) and (5) injury + LLLT group (n = 30). Cryoinjury was performed on the belly of the tibialis anterior (TA) muscle. LLLT was performed daily with an AlGaAs laser (780 nm; beam spot of 0.04 cm(2), output power of 40 mW, power density of 1 W/cm(2), energy density of 10 J/cm(2) and 10-s exposure time). Animals were euthanized at 1, 3 and 7 days. The TA muscles were removed and weighed. Morphological aspects were evaluated using H & E staining. The amount and distribution of collagen fibers were evaluated by picrosirius staining. Characterization and activity of MMP-2 were evaluated by zymography and Western blot techniques, respectively. The results revealed that LLLT induced a reduction in inflammatory infiltrate and myonecrosis after 1 day, an increase in the number of blood vessels after 3 and 7 days as well as an increase in the number of immature muscle fibers and MMP-2 gelatinase activity after 7 days. In conclusion, LLLT has a positive effect on the inflammatory process, MMP2 activity and collagen organization and distribution in the repair process of rat skeletal muscle.

Analysis of transferability of microsatellite primers (SSR) in wild Passiflora species and intraspecific genetic diversity in Passiflora alata.

The genus Passiflora L. is the most representative of Passifloraceae, with over 500 known species, among which 150-200 originated from Brazil. In addition to the great commercial importance of this genus for the fruit market, many of the species have exotic flowers with a huge diversity of colors and can thereby be exploited as ornamental plants. This study was aimed at investigating the transferability of microsatellite primers in wild Passiflora species (P. cacao, P. cincinnata, P. glandulosa, P. gibertii, and P. mucronata) and characterizing 29 P. alata accessions using microsatellite primers that were previously developed in a library enriched with microsatellites from P. edulis f. flavicarpa for P. alata. The interspecies cross-amplification rate varied, and P. cacao exhibited the highest rate of amplification, suggesting a greater degree of proximity to P. edulis. The study of intraspecific accessions in P. alata found genetic similarity, with values ranging from 0.47 to 1.00 and an average similarity of 0.74. Hence, this study revealed the intraspecific genetic variability of P. alata in the Universidade Estadual de Santa Cruz's Active Germplasm Bank and will lead to the adoption of mating strategies between accessions; thus making their use more suitable for breeding purposes.

Antiferromagnetic spatial ordering in a quenched one-dimensional spinor gas.

We have experimentally observed the emergence of spontaneous antiferromagnetic spatial order in a sodium spinor Bose-Einstein condensate that was quenched through a magnetic phase transition. For negative values of the quadratic Zeeman shift, a gas initially prepared in the F=1, m(F)=0 state collapsed into a dynamically evolving superposition of all three spin projections, m(F)=0, ±1. The quench gave rise to rich, nonequilibrium behavior where both nematic and magnetic spin waves were generated. We characterized the spatiotemporal evolution through two particle correlations between atoms in each pair of spin states. These revealed dramatic differences between the dynamics of the spin correlations and those of the spin populations.

Karyotype variation in cultivars and spontaneous cocoa mutants (Theobroma cacao L.).

Four mutant cocoa accessions with morphological changes and a cultivar sample were karyomorphologically characterized. Slides were prepared by enzymatic digestion of the root meristem and squashed in 45% acetic acid, followed by 2% Giemsa staining. The chromosome number of 2n = 20 was seen in all accessions. The karyotype formula for Cacau Comum and Cacau Rui was 2n = 20m. Submetacentric chromosomes were observed in Cacau Pucala and Cacau Jaca, both with 2n = 18m + 2sm, but the karyotype formula for Cacau Sem Vidro was 2n = 16m + 4sm. Satellites were located on the long arm of the 1st and 2nd chromosome pairs of Cacau Comum, whereas Cacau Pucala had satellites on the 6th chromosome pair. Greater karyotypic variation in Cacau Sem Vidro was found, whose 1st and 2nd chromosome pairs had satellites on the long arm and 6th and 10th pairs had satellites on the short arm. Analysis revealed a lower average chromosome length in Cacau Comum (1.53 ± 0.026 µm) and a higher length in Cacau Sem Vidro (2.26 ± 0.038 µm). ANOVA revealed significant difference (P < 0.01) for the average chromosome length and the length of chromosome pairs within and between accessions. The average chromosome lengths of mutants of Cacau Rui and Cacau Jaca were not statistically different by the Tukey test at 5% probability. The karyotypic diversity observed in this study is not necessarily associated with the changing character of the accessions analyzed, but may reflect the genetic variation observed in Theobroma cacao.

Emergence of Majorana and Dirac particles in ultracold fermions via tunable interactions, spin-orbit effects, and Zeeman fields.

We discuss the emergence of rings of zero-energy excitations in momentum space for superfluid phases of ultracold fermions when spin-orbit effects, Zeeman fields, and interactions are varied. We show that phases containing rings of nodes possess nontrivial topological invariants, and that phase transitions between distinct topological phases belong to the Lifshitz class. Upon crossing phase boundaries, existing massless Dirac fermions in the gapless phase annihilate to produce bulk zero-mode Majorana fermions at phase boundaries, and then become massive Dirac fermions in the gapped phase. We characterize these tunable topological phase transitions via several spectroscopic properties, including excitation spectrum, spectral function, and momentum distribution.

Enhanced transport of spin-orbit-coupled Bose gases in disordered potentials.

Anderson localization is a single-particle localization phenomena in disordered media that is accompanied by an absence of diffusion. Spin-orbit coupling (SOC) describes an interaction between a particle's spin and its momentum that directly affects its energy dispersion, for example, creating dispersion relations with gaps and multiple local minima. We show theoretically that combining one-dimensional spin-orbit coupling with a transverse Zeeman field suppresses the effects of disorder, thereby increasing the localization length and conductivity. This increase results from a suppression of backscattering between states in the gap of the SOC dispersion relation. Here, we focus specifically on the interplay of disorder from an optical speckle potential and SOC generated by two-photon Raman processes in quasi-one-dimensional Bose-Einstein condensates. We first describe backscattering by using a Fermi golden rule approach, and then numerically confirm this picture by solving the time-dependent one-dimensional Gross-Pitaevskii equation for a weakly interacting Bose-Einstein condensate with SOC and disorder. We find that on the tens of millisecond timescale of typical cold atom experiments moving in harmonic traps, initial states with momentum in the zero-momentum SOC gap evolve with negligible backscattering, while without SOC these same states rapidly localize.

Evolution from BCS to Berezinskii-Kosterlitz-Thouless superfluidity in one-dimensional optical lattices.

We analyze the finite temperature phase diagram of fermion mixtures in one-dimensional optical lattices as a function of interaction strength. At low temperatures, the system evolves from an anisotropic three-dimensional Bardeen-Cooper-Schrieffer (BCS) superfluid to an effectively two-dimensional Berezinskii-Kosterlitz-Thouless (BKT) superfluid as the interaction strength increases. We calculate the critical temperature as a function of interaction strength, and identify the region where the dimensional crossover occurs for a specified optical lattice potential. Finally, we show that the dominant vortex excitations near the critical temperature evolve from multiplane elliptical vortex loops in the three-dimensional regime to planar vortex-antivortex pairs in the two-dimensional regime, and we propose a detection scheme for these excitations.

Cytogenetics and morphological delimitation between three species of Passiflora L. (subgenus Distephana Cervi).

Several studies on cytogenetic characterisation of passion flowers are helpful to elucidate doubts about taxa relationships, delimitation and classification into more coherent groups based on karyomorphological data. Molecular and conventional cytogenetic techniques were applied to three Passiflora species with red flowers, P. coccinea, P. vitifolia and P. tholozanii, for species karyotype relationships. Additionally, for descriptive morphology, were used flowers, leaves and seeds. Results describe for the first time the karyomorphological and chromosome number (2n = 18) for P. tholozanii. anova was performed (P < 0.05) and statistical significance for average chromosome size (CV: 16.53%) between species. Genomic in situ hybridisation (GISH) proved relationships between P. coccinea and P. tholozanii, which suggests a common origin, however, we could not identify hybridisation between genomic probes from P. vitifolia in P. tholozanii chromosomes. Among the species analysed, P. tholozanii has great similarity in karyotypic and morphology to P. coccinea but not to P. vitifolia. We suggest the inclusion of P. tholozanii in the same subgenus and section as P. coccinea based on the similarity in karyomorphological and morphological traits between the species. Additionally, GISH might indicate a common or hybrid origin of P. tholozanii.

Quantum Phases of Two-Component Bosons with Spin-Orbit Coupling in Optical Lattices.

Ultracold bosons in optical lattices are one of the few systems where bosonic matter is known to exhibit strong correlations. Here we push the frontier of our understanding of interacting bosons in optical lattices by adding synthetic spin-orbit coupling, and show that new kinds of density- and chiral-orders develop. The competition between the optical lattice period and the spin-orbit coupling length - which can be made comparable in experiments - along with the spin hybridization induced by a transverse field (i.e., Rabi coupling) and interparticle interactions create a rich variety of quantum phases including uniform, non-uniform and phase-separated superfluids, as well as Mott insulators. The spontaneous symmetry breaking phenomena at the transitions between them are explained by a two-order-parameter Ginzburg-Landau model with multiparticle umklapp processes. Finally, in order to characterize each phase, we calculated their experimentally measurable crystal momentum distributions. PACS numbers: 67.85.-d,67.85.Hj,67.85.Fg.

A p53-bound enhancer region controls a long intergenic noncoding RNA required for p53 stress response.

Genome-wide chromatin studies identified the tumor suppressor p53 as both a promoter and an enhancer-binding transcription factor. As an enhancer factor, p53 can induce local production of enhancer RNAs, as well as transcriptional activation of distal neighboring genes. Beyond the regulation of protein-coding genes, p53 has the capacity to regulate long intergenic noncoding RNA molecules (lincRNAs); however, their importance to the p53 tumor suppressive function remains poorly characterized. Here, we identified and characterized a novel p53-bound intronic enhancer that controls the expression of its host, the lincRNA00475 (linc-475). We demonstrate the requirement of linc-475 for the proper induction of a p53-dependent cell cycle inhibitory response. We further confirm the functional importance of linc-475 in the maintenance of CDKN1A/p21 levels, a cell cycle inhibitor and a major p53 target gene, following p53 activation. Interestingly, loss of linc-475 reduced the binding of both p53 and RNA polymerase II (RNAPII) to the promoter of p21, attenuating its transcription rate following p53 activation. Altogether, our data suggest a direct role of p53-bound enhancer domains in the activation of lincRNAs required for an efficient p53 transcriptional response.

Analysis of the linkage between fibronectin alternative spliced sites during ageing in rat tissues.

The modulation of fibronectin (FN) functions in cell-cell and cell-substrate interactions in a variety of physiological situations is achieved by the selective expression of different isoforms, which in the rat are generated by alternatively splicing of at least three regions of the molecule: EIIIA, EIIIB and V. Extensive information has been collected on the regulation of the differential processing of the single alternatively spliced regions but up to now there was scant knowledge about a possible coordinated expression of the three regions in the same transcript. Using a long range RT-PCR system we have shown that most of the splicing regulation is autonomous for each individual region but we have also observed a preferential expression of the EIIIA+ form linked to the EIIIB- variant that is age independent. Furthermore the analysis of the single regions showed interesting variations occurring in brain during the ageing. There is a decrease in the V120 form between the 6- and the 24-month-old rat brain (from 57% to 39%), whereas despite a constant prevalence of the EIIIA- form in the young rats (65%) there is a random individual variation of this form in the old animals. Noteworthy no variations have been detected in the EIIIB region (90% EIIIB-). These data suggest a role for the V and EIIIA regions, but not for the EIIIB, during the ageing process at least in brain, since no variations were detected in kidney between the 6- and 24-month-old animals.

Alternative splicing of a previously unidentified CFTR exon introduces an in-frame stop codon 5' of the R region.

The cystic fibrosis transmembrane conductance regulator (CFTR) has been extensively characterized as the carrier of the basic defect in cystic fibrosis. CFTR is part of a growing family of proteins encoded by a single gene, the variant isoforms of which are generated by alternative splicing or RNA editing. We have analyzed the CFTR mRNA in the region of exons 10-11 in T84 cells and detected an alternatively spliced exon (10b) accounting for about 5% of the CFTR mRNA. The exon 10b found in both the human and mice genomes, introduces an in-frame stop codon. The resulting mRNA is translated into a truncated CFTR protein, identified in T84 cells by immunoprecipitation with the CFTR-specific monoclonal antibody MATG 1061. The insertion of a differentially spliced exon carrying an in-frame stop codon is a novel cellular mechanism for the production of a protein sharing common sequences with another, but having different properties and functions.