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Alstroemeria (Alstroemeriaceae) displays a conserved and highly asymmetric karyotype, where most rDNA sites can be properly recognized by the size and morphology of the chromosomes. We analyzed the intraspecific variation of rDNA sites in A. longistaminea and compared with their distribution in other species (A. caryophyllaea and A. piauhyensis) and a representative of a sister genus, Bomarea edulis. All three species of Alstroemeria presented 2n = 16, and one to six B chromosomes were found in some individuals of A. longistaminea. There was a set of 12 conserved rDNA sites (four 5S and eight 35S) and up to 11 variable sites. B chromosomes were almost entirely covered by 35S signals, coupled with tiny 5S sites. Noteworthy, most rDNA sites found in A. caryophyllaea and A. piauhyensis were localized in chromosome positions similar to those in A. longistaminea, suggesting the existence of conserved hotspots for rDNA accumulation. Some of these hotspots were absent in Chilean Alstromeria as well in B. edulis. We propose that insertions of rDNA sequences on chromosomes do not occur randomly but rather on preferential sites or hotspots for insertions. The maintenance of these arrays, however, may be favored/constrained by different factors, resulting in stable or polymorphic sites. Key words: Alstroemeria, Bomarea, B chromosomes, CMA/DAPI bands, genome size, rDNA sites. L'Alstroemeria (Alstroemeriaceae) affiche un caryotype conserve et tres asymetrique, au sein duquel la plupart des sites d'ADNr sont reconnus sur la base de la taille et de la morphologie des chromosomes. Les auteurs ont analyse la variation intraspecifique pour les sites d'ADNr au sein de l'A. longistaminea et ils ont compare cette distribution avec celle rencontree chez d'autres especes (A. caryophyllaea et A. piauhyensis) ainsi qu'un representant d'un genre proche, Bomarea edulis. Les trois especes d'Alstroemeria presentaient 2n = 16 chromosomes et d'un a six chromosomes B ont ete observes chez certains individus de l'A. longistaminea. Douze sites d'ADNr conserves (quatre 5S et huit 35S) et jusqu'a 11 sites variables ont ete notes. Les chromosomes B etaient presque entierement couverts de signaux 35S et de quelques sites 5S de tres petite taille. Fait notable, la plupart des sites d'ADNr trouves chez l'A. caryophyllaea et l'A. piauhyensis etaient situes a des positions chromosomiques semblables a celles chez l'A. longistaminea, ce qui suggere des sites conserves pour l'accumulation d'ADNr. Certains de ces sites preferentiels etaient absents chez les Alstroemeria du Chili de meme que chez le B. edulis. Les auteurs proposent que les insertions de sequences d'ADNr dans les chromosomes ne surviennent pas de maniere aleatoire, mais plutot a des sites preferentiels d'insertion. Le maintien de ces suites de sequences, cependant, pourrait etre favorise/contraint par differents facteurs, ce qui produirait le polymorphisme de ces sites. [Traduit par la Redaction] Mots-cles : Alstroemeria, Bomarea, chromosomes B, bandes CMA/DAPI, taille du genome, sites d'ADNr., Introduction 5S and 35S ribosomal DNA arrays (rDNA) are by far the most extensively investigated chromosomal regions in eukaryotes, mainly because DNA sequences for both genes are highly conserved and [...]

The Black Hills State University Underground Campus (BHUC) houses a low background counting facility on the 4850' level of the Sanford Underground Research Facility. There are currently four ultra-low background, high-purity germanium detectors installed in the BHUC and it is anticipated four more detectors will be installed within a year. In total, the BHUC will be able to accommodate up to twelve detectors with space inside a class 1000 cleanroom, an automated liquid nitrogen fill system, on-site personnel assistance and other required utilities.

Coffee, one of the top ten most globally traded commodities, can be grown in different agricultural regions presenting peculiar characteristics. Thus, the determination of inorganic nutrients in ground-roasted coffee has nutritional relevance and allows authentication as well as tracking of the origin of the product. Analytical methods routinely used to determine inorganic nutrients in food are based on time-consuming steps that involve acid digestion followed by elemental quantification. In this study, analytical strategies for the direct determination of inorganic macronutrients (P, K, Ca, and Mg) in commercial samples of ground-roasted coffee were evaluated by portable X-ray fluorescence spectrometry (pXRF) using two commercial spectrometers. Two calibration approaches were tested: (i) using plant-based certified reference materials (CRMs); (ii) matrix-matched calibration, using samples of ground-roasted coffee as well as the corresponding solid residues resulting from infusion, the spent coffee grounds (SCG). The analyte mass fractions in these samples were determined by the reference method (decomposition using HNO3 and H2O2 followed by ICP OES measurements). In the latter method, calibration models were built using reference values and analytical signals obtained by pXRF. Pressed pellets from the samples (CRMs, ground-roasted coffee, and SCG) were prepared. The samples were irradiated for 50 s using both spectrometers under two experimental conditions: X-ray tube voltage of 15 kV and 50 kV. Calibration models with excellent linearity were obtained (r ≥ 0.90) for all analytes. The proposed matrix-matched calibration method was considered the most accurate approach for elemental determination (mainly P and K) in samples of ground-roasted coffee as well as in the spent coffee grounds, an alternative agricultural fertilizer. [ABSTRACT FROM AUTHOR]

Interspecific hybridization and genome duplication to form allopolyploids are major evolutionary events in angiosperms. In the parasitic genus Cuscuta (Convolvulaceae), molecular data suggested the existence of species of hybrid origin. One of them, C. veatchii, has been proposed as a hybrid between C. denticulata and C. nevadensis, both included in sect. Denticulatae. To test this hypothesis, a cytogenetic analysis was performed with CMA/DAPI staining and fluorescent in situ hybridization using 5S and 35S rDNA and genomic probes. Chromosomes of C. denticulata were small with a well-defined centromeric region, whereas C. nevadensis had larger, densely stained chromosomes, and less [CMA.sup.+] heterochromatic bands. Cuscuta veatchii had 2n = 60 chromosomes, about 30 of them similar to those of C. denticulata and the remaining to C. nevadensis. GISH analysis confirmed the presence of both subgenomes in the allotetraploid C. veatchii. However, the number of rDNA sites and the haploid karyotype length in C. veatchii were not additive. The diploid parentals had already diverged in their chromosomes structure, whereas the reduction in the number of rDNA sites more probably occurred after hybridization. As phylogenetic data suggested a recent divergence of the progenitors, these species should have a high rate of karyotype evolution. Key words: allopolyploidy, CMA/DAPI bands, homogenization of 35S rDNA repeats, interphase nuclei structure, 5S and 35S rDNA sites. L'hybridation interspecifique et la duplication genomique menant a la formation d'allopolyploides constituent des evenements importants dans l'evolution des angiospermes. Au sein du genre Cuscuta (Convolvulaceae) de plantes parasites, les donnees moleculaires suggerent l'existence d'especes d'origine hybride. Il a ete propose que l'une d'elles, le C. veatchii, resulterait de l'hybridation entre le C. denticulata et le C. nevadensis, toutes deux faisant partie des Denticulatae. Pour tester cette hypothese, une analyse cytogenetique a ete realisee au moyen de coloration CMA/DAPI et d'hybridation in situ en fluorescence a l'aide des sondes d'ADNr 5S et 35S ainsi qu'a l'aide de sondes genomiques. Les chromosomes du C. denticulata etaient petits et presentaient des regions centro-meriques bien definies, tandis que ceux du C. nevadensis etaient plus grands, intensement marques et presentaient moins de bandes heterochromatiques [CMA.sup.+].Le C. veatchii comptait 2n = 60 chromosomes, dont environ 30 etaient semblables a ceux du C. denticulata et les autres semblables a ceux du C. nevadensis. L'analyse GISH a confirme la presence des deux sous-genomes au sein de l'allotetraploide C. veatchii. Cependant, le nombre de sites d'ADNr et la longueur du caryotype haploide chez le C. veatchii n'etaient pas additifs. Les parents diploides avaient deja diverge en ce qui a trait a leur structure chromosomique, tandis que la reduction dans le nombre de sites d'ADNr est probablement survenue apres l'hybridation. Puisque les donnees phylogenetiques ont suggere une divergence recente des especes parentales, ces especes doivent presenter une evolution caryotypique rapide. [Traduit par la Redaction] Mots-cles : allopolyploidie, bandes CMA/DAPI, homogeneisation des repetitions d'ADNr 35S, structure des noyaux en interphase, sites d'ADNr 5S et 35S., Introduction Events of interspecific hybridization are common in the evolution of most genera of angiosperms. If diploid hybrids retain their fertility they will be able to generate a wide diversity [...]

The condensation patterns (CPs) of prophase chromosomes represent poorly explored and little understood karyotype features. Three distinct chromosome domains are observed in conventionally stained prophases of most angiosperms with small chromosomes: heterochromatin and early condensing euchromatin (ECEu), which are observed as early condensing regions (ECRs), and late condensing euchromatin or late condensing regions (LCRs). All three prophase domains have been often reported in the Annonaceae species. To gain a better understanding of these regions, we investigated the CPs, heterochromatic bands, and rDNA sites in seven Annona species with 2n  = 14, 28, and 54 and Xylopia frutescens with 2 n  = 16. Besides, histone H4K5 acetylation, telomeric sites, and DNA methylation were analysed in some of these species. LCRs corresponded to a small hyperacetylated, and hypomethylated fraction of the metaphase chromosomes. During interphase, the chromocentres displayed variable proportions of heterochromatin and ECEu. The LCRs and ECRs were conserved even between disploid and polyploid species, whereas rDNA sites and heterochromatic bands varied in number and location. Our data suggest that chromatin compartmentalization in ECR and LCR regions may represent the simplest functional organization of the small chromosomes of Annonaceae, while the remaining characters are less relevant. [ABSTRACT FROM AUTHOR]

Advances in oyster farming have been achieved with biotechnological applications, such as chromosome manipulations aimed at polyploidy. The bivalve Anomalocardia brasiliana is of considerable importance to artisanal fishing activities and is a potential organism for aquaculture in Brazil. The cytogenetic behavior of polar bodies during meiosis provides essential information for chromosome manipulation directed at the production of triploid organisms. The objective of the present study was to identify postfertilization times in which the polar bodies are expelled and determine the most frequent number of chromosomes in A. brasiliana. Individuals were caught on the coast of the state of Pernambuco, in northeast Brazil, and subsequently induced to release the gametes. Samples of the oocyte solution were taken before and every 2 min after fertilization. The material was fixed in Carnoy's solution, stained with 4',6-diamidino-2-phenylindole and photographed under an epifluorescence microscope. Among the 50 oocytes analyzed in metaphase I, 19 bivalents were found. The release of the first polar body was detected 10 min after fertilization among 70% of the eggs, whereas the second polar body was released at 16 min among 62% of the eggs. This work provides relevant information on the time of initiation of shock treatments for chromosome set manipulation, aiming triploids of this important marine fishery resource in Brazil. KEY WORDS: Anomalocardia brasiliana, polar bodies release timing, number of chromosomes, polyploid, INTRODUCTION Chromosome manipulation is a strategy that has been adopted in aquaculture activities around the world since the 1980s to accelerate the growth of bivalves (Guo et al. 2009, Maldonado-Amparo [...]