Table of contents: 2021
Flavonoids are a group of natural polyphenols that are typically present in many higher plants as secondary metabolites with low molecular weight. Diosmin (3′,5,7-trihydroxy-4′-methoxyflavone-7-ramnoglucoside) is a naturally occurring flavonoid found in relatively large quantities in citrus fruits. We examined the cytotoxic, antiangiogenic and antimicrobial activity of diosmin. The cytotoxic effect was assessed by the WST-1 test. Cellular DNA fragmentation was determined by measuring BrdU-labeled DNA fragments. The mRNA and protein levels were assessed by qRT-PCR and Western blot. The minimal inhibitory concentrations (MIC) of diosmin for six Gram-positive and nine Gram-negative bacteria were determined by using a microdilution method. Diosmin significantly and selectively inhibited proliferation depending on concentration and exposure time. Following diosmin treatment of MDA-MB-231 cells, a concentration-dependent and time-dependent increase in the number of apoptotic BrdU-labeled DNA fragments was observed. Exposure of MDA-MB-231 breast cancer cells to diosmin for 24 h markedly increased the mRNA expression of Bax and caspase-3, whereas the expressions of Bcl-2 and Bcl-XL were decreased. Furthermore, Western blotting demonstrated that protein expression of Bcl-2 and Bcl-XL was downregulated, while the expression of Bax and caspase-3 proteins was upregulated. Based on the MICs, significant activity was only seen against Gram-positive bacteria. We conclude that diosmin is a potential candidate for use in the treatment of breast cancer and for controlling infection.
A possible strategy to increase grain yield in common beans (Phaseolus vulgaris) is to obtain lines with earlier flowering and a longer grain filling period, associated with a higher dry matter accumulation rate. We examined the genetic control of these traits to investigate whether it is possible to select lines with earlier flowering, a longer period of grain formation, and a higher dry matter accumulation rate in the grain. We also sought to determine whether it would be feasible to use these traits as an indirect selection strategy for grain yield. Ten lines belonging to the Andean and Mesoamerican gene pool were crossed in a diallel scheme in Lavras, MG. The hybrids together with the parents were evaluated in a randomized block design in three seasons, corresponding to generations F2, F3 and F4. The variables measured were number of days to flowering (NDF), grain dry matter (GDM), grain yield (YIELD), number of days to physiological maturity (NDPM) and dry matter accumulation rate (RATE). We found that for NDF, NDPM and RATE, the general combining ability (GCA) explained most of the variation. Both GCA and the specific combining ability were important for YIELD. However, for this trait, the estimate of heterosis was significant, but negative (-27.7%), when the crosses involved the Andean x Mesoamerican lines. The estimated values of correlation between NDPM x NDF were positive (0.72 **), and negative between NDF x RATE (-0.52 **) and NDPM x RATE (-0.43*). Consequently, none of the populations presented potential for obtaining new lines with high grain yield, based on indirect selection for early flowering and traits associated with grain filling.
Polynemidae, commonly known as threadfins, are important fishing and aquaculture species. This is a peculiar fish group that is morphologically characterized by long tactile filaments of the pectoral fins. Although inserted in the Percomorpha, its relationships with other groups of this clade are uncertain. Cytogenetic investigations have helped clarify various evolutionary aspects of marine fish groups, including stock delimitation, speciation, taxonomy, hybridization, phylogenetic relationship, sex chromosomes, and genome changes. However, the chromosomal characteristics of threadfins are still unknown. We investigated the chromosomal features of two cryptic species, Polydactylus virginicus and P. oligodon found in Northeast Brazilian coastal waters (Tropical Southwestern Atlantic region). Cytogenetic data were obtained by conventional staining (Giemsa and fluorochrome staining, C-banding and Ag-NORs techniques) and molecular cytogenetic analyses through fluorescent in situ hybridization using rDNA probes (18S and 5S rDNA). The two species have similar karyotypes at the macro and microstructural levels. An unexpected high diploid number was found, with 2n=58 acrocentric chromosomes, including four microchromosome pairs. The expanded karyotypes are a synapomorphy for these species, likely resulting from sharing at least five chromosome fissions from a basal karyotype with 2n=48. Besides the macrostructural karyotype similarities, the Ag-NOR/GC-rich/18S rDNA (chromosome 19) and 5S rDNA (chromosome 20) loci have an identical organization in apparently homeolog chromosomes of these species, suggesting the conservation of large syntenic chromosomal regions. We conclude that although chromosome fissions are very rare events among other Carangaria fish, they played an important disruptive role in the evolution of some species of Polynemidae.
Although environmental toxicity of high concentrations of nanoparticles (NP) is well reported in the literature, information about their effects on biological systems at environmentally relevant concentrations remains scarce. We investigated whether low ZnO-NP concentrations influence the dynamics of cell division processes, cause nuclear abnormalities and induce changes in the genomic DNA using Allium cepa root cells. Healthy A. cepa bulbs were exposed to environmentally relevant concentrations of ZnO-NP for 48 hours under four different environmental conditions, namely: optimistic, median, pessimistic and known toxic. Mitotic index (MI), chromosomal abnormalities (CAs) and genomic stability based on DNA markers were estimated. ZnO-NPs induced significant changes in MI and CAs, with clear dose-response effects, even at very low concentrations and short exposure times. This outcome is clear evidence of negative effects. In addition, we evidenced instability in the repair mechanism of DNA mutated due to low concentrations of ZnO NPs based on RAPD-PCR results. Therefore, even short-term exposure of eukaryotic cells to low concentrations of ZnO-NP can damage cells and, consequently, negatively affect their biological functioning.
Molecular characterization of genes is a tool used to understand gene function. Chitin is the most abundant nitrogenous organic compound in nature; it is basically inert, but it can be transformed by the action of chitinases to several derivatives, which are of great interest in various areas of industry. These enzymes are widely distributed in many organisms and can be potentially used in genetic engineering to add characteristics that increase its activity. We examined 10 chitenase genes from 10 different strains of Stenotrophomonas maltophilia native to Chiapas, Mexico that have different enzymatic activities. After sequencing of the gene, a bioinformatic analysis was performed, which revealed an average length of 2100 bp and 64.7% G+C content of the genes. The open reading frame consists of 699 amino acids, which corresponds to an average molecular mass of 72.4 kDa, and an isoelectric point of 6.66. The genes exhibited between 99.3 and 100% identity. Additionally, the 3D structure of the chitinolytic enzyme was predicted using the structure of a chitinase from Streptomyces thermoviolaceus as a template. Results suggested that the chitinase of S. maltophilia contains four characteristic domains of these enzymes, the Chia1_BD, Big_3_5, type III fibronectin (FN3), and GH18 domains. This study provides basic knowledge for enzyme design using genetic engineering.
There is a lack of information regarding variables that regulate the expression of the yield potential of maize. We studied yield components of maize under different arrangements on field, in the southwest region of the state of Goiás, Brazil. The soil of the experimental area is classified as Typic Orthotic. The experimental design was randomized blocks, in a 9x2 factorial scheme, with nine maize hybrids [30F53, 30F35, P3630, P3898, P3779, AG7098, DKB 310, CD 3612 and SHS 7990] and two spatial arrangements (single rows (45x45 cm) and twin rows (45x90x45 cm), with four replicates. The seeding was made with a one row sowing machine, and soil fertilizing carried out according to technical recommendations. Pest and weed control was employed when required, using an integrated management. The results were submitted to variance analysis, using a means comparison by Scott-Knot test and by multivariate models. The results of the interactions of maize hybrids and spatial arrangements were significant for all the variables with exception of the foliar area index. There were differences in correlations between the variables, with distinct canonical correlations and cultivar groupings. The maize hybrids DKB310 and P3839 stood out, showing satisfactory yield in both spatial arrangements. The modeling of spatial arrangements influenced the behavior of maize hybrids, especially DKB310 and P3898, which showed satisfactory yields in both spatial arrangements.
Polymorphisms of the transcription factor 7–like 2 (TCF7L2) gene have been associated with susceptibility to type 2 diabetes (T2D) in various ethnic populations, but have not been previously studied in a Nigerian population. We investigated the relationship between the TCF7L2 rs12255372 (G/T) polymorphism and type 2 diabetes (T2D) in a Nigerian population. This was a preliminary case–control study that included 73 T2D patients and 75 non-diabetic (ND) controls. Following blood collection, fasting blood glucose (FBG), triglyceride (TG), total cholesterol (TC), high density lipoprotein-cholesterol (HDL-c) and low density lipoprotein-cholesterol (LDL-c) were assayed. PCR-Restriction Fragment Length Polymorphism (RFLP) was employed to molecularly genotype for the TCF7L2 G/T polymorphism using the MluCI restriction enzyme. The GG homozygote genotype was more frequent in ND controls (38.5%) than in T2D patients (23%) while the TT genotype was more frequent in T2D patients (25.7%) than in ND controls (11.5%). Thus, the TCF7L2 G/T polymorphism was associated (P < 0.05) with T2D. The recessive model showed the greatest risk of T2D when the TT genotype was compared to the GX (GG+GT) genotype (odds ratio (OR): 3.91; 95% confidence interval (CI): 1.93-7.96, P < 0.001). The FBG and HDL-c were significantly different (P < 0.05) in subjects with the mutant (GT and TT) genotypes compared to the GG genotype. In conclusion, the TCF7L2 G/T polymorphism was associated with increased risk of T2D in a Nigerian population. This variant could affect pathophysiological markers associated with risk of T2D. Further studies are needed in other populations in Nigeria to confirm the effects of this polymorphism on pathophysiological markers of T2D.
The woodiness disease induced by the Cowpea aphid-borne mosaic virus (CABMV) is regarded as a limiting factor for passion fruit production. We estimated genetic parameters for resistance and agronomic performance-related traits and selected genotypes resistant to CABMV in segregating populations of passion fruit. The experiment was a randomized-block design with four replicates, consisting of six full-sibling first backcross genotype families, in which 319 genotypes were evaluated. The disease symptoms were evaluated based on spontaneous occurrence of CABMV, using a scale of scores in young leaves, plant and fruits. Based on these scores, we estimated the area under the disease progress curve (MAUDPC). Agronomic traits were also assessed: fruit weight per plant and number of fruits per plant. The variance components and genetic value of each genotype were estimated for each variable via mixed models. The MAUDPC values ranged from 401.25 to 1192.5, indicating considerable genetic variability. The high individual narrow-sense heritability value for the MAUDPC trait (0.95) indicates the possibility of genotypic selection within CABMV-resistant families. For the production-related traits, even with low heritability values, it was possible to obtain genetic gains in individual selection, which ranged from 4.99 to 6.24% for fruit weight and 22.64 to 28.70% for number of fruits. The genotypes chosen to compose the next backcross generation should be selected based on resistance to CABMV, which is the main objective of the program, since agronomic traits can be recovered from backcrosses. Of the 30 individuals ranked for CABMV tolerance, genotypes 501, 506, and 597 were selected to compose the next generation of backcrosses. These had the lowest values for MAUDPC.
Knowledge of lactation curves in dairy cattle is essential for understanding the animal production in milk production systems. Genomic prediction of lactation curves represents the genetic pattern of milk production of the animals in the herd. In this context, we made genomic predictions of lactation curves through genome-wide selection (GWS) to characterize the genetic pattern of lactation traits in Girolando cattle based on parameters estimated by nonlinear mixed effects (NLME) models. Data of 1,822 milk control records from 226 Girolando animals genotyped for 37,673 single nucleotide polymorphisms were analyzed. Nine NLME models were compared to identify the equation with the best fit. The lactation traits estimated by the best model were submitted to GWS analysis, using the Bayesian LASSO method. Then, based on the genomic estimated breeding values (GEBVs) obtained, genomic predictions of lactation curves were constructed, and the genetic parameters were calculated. Wood's equation showed the best fit among the evaluated models. Heritabilities ranged from 0.09 to 0.29 for the seven lactation variables (initial production, rates of increase and decline, lactation peak, time to peak yield, persistence and total production). The correlations among GEBVs ranged from -0.85 to 0.98. The concordances between the best animals selected according to the selected traits were greater when the correlations between GEBVs for these traits were also high. Consequently, the methodology allowed us to identify the best nonlinear model and to construct the genetic lactation curves of a Girolando cattle population, as well as to assess the differences between animals and the association between lactation variables.
Peach is a temperate fruit species that is cultivated under various edaphoclimatic conditions all over the world. In Brazil, in the early 1950s, peaches were planted only in São Paulo state and in the Southern states, and the harvest period was restricted to 15 days. Currently, mainly due to peach breeding programs, it is cultivated in subtropical areas and even in high altitude tropical areas, with a harvest period of over 100 days. Knowledge of genetic, phenotypic and environmental parameters that influence characters of economic importance is crucial for guiding breeding programs. The objectives of this study were to estimate the heritability of phenological characters, to evaluate their distribution within populations, to test the possible existence of maternal effect and to evaluate the relationship of these traits with brown rot incidence (Monilinia fructicola). The study was performed in Pelotas, RS, Brazil during 2015-2016 to 2017-2018 seasons. Sixteen first generation (F1) progenies were evaluated, 10 of them being reciprocal crosses. All genotypes were cultivated in the same area, under the same cultural practices (without fungicide application). Full bloom was considered when more than 50% of flowers were open, and the harvest, when more than 10 fruits reached commercial maturity, the fruit development period being calculated by the difference between full bloom and harvest dates. Brown rot incidence was estimated by the percentage of fruits with symptoms. Broad-sense heritability estimates for full bloom date, harvest date, and fruit development period were high (95 to 98%), and narrow-sense heritabilities were medium to high (65 to 72%). A segregation study of these traits suggests a maternal effect on their heritability, mainly for full bloom and harvest date. The three phenological characters were significantly correlated, and only harvest date had a negative and significant correlation (-0.12) with brown rot incidence.