Exploring the Relationship between Spontaneous Sister Chromatid Exchange and Genome Instability in Two Cryptic Species of Non-Human Primates.

There are extensive studies on chromosome morphology and karyotype diversity in primates, yet we still lack insight into genomic instability as a key factor underlying the enormous interspecies chromosomal variability and its potential contribution to evolutionary dynamics. In this sense, the assessment of spontaneous sister chromatid exchange (SCE) frequencies represents a powerful tool for evaluating genome stability. Here, we employed G-banding, fluorescence plus Giemsa (FPG), and chromosome orientation fluorescence in situ hybridization (CO-FISH) methodologies to characterize both chromosome-specific frequencies of spontaneously occurring SCE throughout the genome (G-SCE) and telomere-specific SCE (T-SCE). We analyzed primary fibroblast cultures from two male species of Ateles living in captivity: Ateles paniscus (APA) and Ateles chamek (ACH). High frequencies of G-SCEs were observed in both species. Interestingly, G-SCEs clustered on evolutionary relevant chromosome pairs: ACH chromosomes 1, 2, 3, 4, and 7, and APA chromosomes 1, 2, 3, 4/12, 7, and 10. Furthermore, a statistically significant difference between the observed and expected G-SCE frequencies, not correlated with chromosome size, was also detected. CO-FISH analyses revealed the presence of telomere-specific recombination events in both species, which included T-SCE, as well as interstitial telomere signals and telomere duplications, with APA chromosomes displaying higher frequencies, compared to ACH. Our analyses support the hypothesis that regions of Ateles chromosomes susceptible to recombination events are fragile sites and evolutionary hot spots. Thus, we propose SCE analyses as a valuable indicator of genome instability in non-human primates.

Standardization of a compensation matrix for the use in an ISHAGE-based single-platform for CD34+ stem cell quantitation on the FACSVia™ flow cytometer.

INTRODUCTION: Becton Dickinson (BD) FACSVia™ is a recently developed flow cytometer with which worldwide clinical experience is limited. Recently, our center started using the single-platform BD Stem Cell Kit (BD SCE) for the quantitation of viable CD34+ (7-aminoactinomycin D-7-AAD-negative cells) on a BD FACSVia™. Currently, there are no formal recommendations for the fluorescence compensation of 7-AAD in this scenario. METHODS: A 3-color fluorescence compensation matrix ("Optimized BD CS&T") was standardized based on the fluorescence of 7-AAD in samples of 27 individuals. The "Optimized BD CS&T" was compared with manual compensation (predicated method) and BD CS&T beads. RESULTS: The analysis of the viable CD34+ cells/mm3 showed a very strong correlation between the manual compensation versus "Optimized BD CS&T" (r = 1.00) and manual versus BD CS&T (r = .99). The analysis of CD34+ viability (%) showed a very strong correlation for manual versus "Optimized BD CS&T" (r = .99). However, for manual versus BD CS&T, the correlation was inferior (r = .86). For viable CD34+ cells/mm3 , Bland-Altman plots showed a better concordance between manual and "Optimized BD CS&T" than between manual and BD CS&T. For CD34+ viability (%), the concordance was very good between manual and "Optimized BD CS&T", while there was a poor concordance between manual and BD CS&T. CONCLUSION: "Optimized BD CS&T" matrix proved to be more precise than the conventional BD CS&T beads. The "Optimized BD CS&T" matrix can be used along with BD SCE kit on BD FACSVia™ flow cytometers.

Evaluation of antioxidant and mutagenic activities of honey-sweetened cashew apple nectar.

In vitro chemical properties and antioxidant potential and in vivo mutagenic activity of honey-sweetened cashew apple nectar (HSCAN), a beverage produced from the cashew pseudo-fruit (Anacardium occidentale L.) and of its constituents were assessed. Analytical procedures were carried out to investigate the honey used in the HSCAN preparation, and the results observed are in accordance with Brazilian legal regulations, except for diastase number. HSCAN and pulp were investigated for ascorbic acid, carotenoid, anthocyanin and total phenolic contents, and both showed high acid ascorbic concentrations. Antioxidant capacity using 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and/or ß-carotene/linoleic acid systems were applied and demonstrated a weak antioxidant capacity of honey and HSCAN, but cashew apple pulp demonstrated high antioxidant capacity. A weakly positive mutagenic effect of cashew pulp 20% was observed using the somatic mutation and recombination test (SMART) in Drosophila melanogaster only in the high-bioactivation (HB) cross. On the contrary, HSCAN was not mutagenic in both standard and high bioactivation crosses. HSCAN exhibited slight antioxidant activity, which could be associated with the high amount of ascorbic acid found in the samples evaluated. The beverage prepared did not induce DNA damage in somatic cells of D. melanogaster, which means that it is neither mutagenic nor recombinagenic in this test system.

Análisis de patrones morfológicos y anatómicos en la embriogénesis somática del banano Williams (AAA) / Analysis of the morphological and anatomical patterns in the somatic embryogenesis of Williams banana (AAA)

La embriogénesis somática representa una herramienta esencial en el mejoramiento genético y en la micropropagación clonal masiva de bananos mejorados. En el presente trabajo se analizaron los patrones morfológicos y anatómicos que ocurren durante la embriogénesis somática del banano Williams, dirigidos a conocer y mejorar este proceso. En la investigación se establecieron suspensiones celulares embriogénicas (SCE) a partir de callo embriogénico obtenido de manos florales inmaduras masculinas, las cuales originaron abundantes embriones que regeneraron plantas. Hacia los tres meses de cultivo se detectaron embriones somáticos (ES) primarios color blanco-crema en las manos florales de los nudos nueve a doce, contados a partir del ápice floral. Al cuarto mes estos ES primarios dieron origen al callo embriogénico, de color blanco crema, estructura granular, con abundantes ES torpedo en su periferia y con una organización celular en tres diferentes zonas. De este callo se cultivaron porciones pequeñas con ES torpedo en medio de multiplicación durante dos meses, dando origen a la SCE I. La misma se tamizó (250 µm) para establecer la SCE II. El sedimento de células y los agregados celulares embriogénicos de ambas SCE se trasladó a medio de maduración. Transcurridos dos meses los embriones maduros se transfirieron a medio de conversión de embriones, lográndose regenerar plantas completas a partir de las dos semanas. Las SCE produjeron numerosos embriones somáticos maduros y mostraron una buena conversión de embriones a plantas y regeneración de plantas. Este sistema de embriogénesis somática permitió la obtención de plantas funcionales en nueve meses.

Somatic embryogenesis represents an essential tool for the genetic improvement and for the mass clonal micropropagation of the improved banana plant. In this present work morphological and anatomical patterns were analyzed in the somatic embryogenesis of Williams banana, to know and enhance this process. In the investigation embryogenic cell suspensions (ECS) were established from embryogenic callus obtained from floral immature male hands, which gave rise to many somatic embryos that regenerated plants. Towards the three months of culture white-cream primary somatic embryos (SE) were detected in the floral hands of the nodes nine to twelve, counted from the floral apex. At the fourth month this primary SE gave origin to a creamy-white embryogenic callus, with granular structure and abundant SE torpedo on its periphery. Cell organization with three different zones was observed in callus. Small portions of this callus were cultivated in the multiplication medium for two months, to originate ECS I. This ECS was filtered through a mesh (250 µm pore size) to establish the ECS II. The sediment of embryogenic cells and cell clusters of the ECS were moved to maturation media. After two months the mature embryos were transferred to conversion medium, and two weeks later, whole plants were developed. The ECS produced numerous mature SE, which showed good conversion of embryos into plants and plant regeneration. This system of somatic embryogenesis permitted the mass production of functional plants in nine months.