On November 2015, one of Brazil's most important watersheds was impacted by the mine waste from Fundão dam collapse in Mariana. The mine waste traveled over 600 km along the Doce River before ...reaching the sea, causing severe devastation along its way. Here we assessed trace element concentrations and cytogenotoxic effects of the released mine waste. Water samples were collected along the Doce River ten days after the disaster in two impacted sites and one non-impacted site. Sampling points were located hundreds of kilometers downstream of the collapsed dam. Water samples were used for trace element quantification and to run an experiment using Allium cepa to test cytogenotoxicity. We found extremely high concentrations of particulate Fe, Al, and Mn in the impacted sites. We observed cytogenotoxic effects such as alterations in mitotic and phase indexes, and enhanced frequency of chromosomal aberrations. Our results indicate interferences in the cell cycle in impacted sites located hundreds of kilometers downstream of the disaster. The environmental impacts of the dam collapse may not only be far-reaching but also very likely long-lasting, because the mine waste may persist in the Doce River sediment for decades.
•Higher concentrations of particulate metals were found in impacted sites.•Cytogenotoxic effects were found in the impacted sites.•Mining waste affected genetic aspects of Allium cepa.•Impacts of the tragedy are far-reaching and long-lasting.
• Premise of the study: Tropical regions have high species diversity, and polyploidization is a major mechanism of speciation in plants. However, few cases of natural polyploidy have been reported in ...tropical regions. Lippia alba, is a tropical, aromatic shrub with a wide distribution, extensive morphological plasticity, and several chemotypes. The species has long been recognized as a diploid with 2n = 30 chromosomes. Recently, two variations in chromosome number (2n = 60; 2n = 12–60) have been reported, suggesting the occurrence of polyploidy within the species.• Methods: Flow cytometry was used to investigate the genome size in 106 accessions from 14 Brazilian States. Conventional and molecular cytogenetic techniques and pollen viability analysis were employed to characterize each chromosome number observed.• Key results: The DNA 1C-value varied from 1.17 to 3.45 pg, showing a large variation in genome size. Five distinct chromosome numbers were observed (2n = 30, 38, 45, 60, 90); three are cytogenetically described here for the first time. The 5S rDNA signals varied proportionally according to each chromosome number, but 45S rDNA sites did not. High rates of meiotic irregularity were observed, mainly in cytotypes with higher chromosome numbers.• Conclusions: The data provide new support for the occurrence of a polyploid series in Lippia alba. We provide a hypothesis for how this complex may have arisen. Other cryptic polyploid complexes may remain undiscovered in tropical regions.
Water pollution is a global environmental issue, and aquatic sediments are important compartments that might act as sinks or sources of contaminants. Once in the environment, inorganic contaminants ...such as metals can cause cytogenotoxic effects that damage genetic material and harm the aquatic community. Biological assays such as the Allium test can be used to investigate potential cytogenotoxicity of contaminated sediments based on the alterations of cell cycle indexes and chromosomal aberration frequencies. Therefore, we aimed to assess the toxicity of sediments from four Brazilian reservoirs using the Allium test. Sediments were sampled and elutriates were prepared in a simulating sediment resuspension in the water column. The Allium test was applied to the elutriates, and the metals copper, chromium, cadmium, lead, zinc, and iron were quantified. The elutriates derived from reservoir sediments were able to reduce the mitotic and anaphase index, increase the prophase and metaphase index, and boost chromosomal aberrations compared to the negative control. The cytogenotoxic effects observed may be linked to the presence of copper, zinc, and iron. Therefore, our results showed that the Allium test was a sensitive tool for warning the occurrence of genotoxic contaminants in sediment elutriates from four Brazilian reservoirs.
Increased periods of prolonged droughts followed by severe precipitation events are expected throughout South America due to climate change. Freshwater sediments are especially sensitive to these ...changing climate conditions. The increased oscillation of water levels in aquatic ecosystems causes enhanced cycles of sediment drying and rewetting. Here we experimentally evaluate the effects of induced drought followed by a rewetting event on the release of carbon dioxide (CO2), methane (CH4), nutrients (nitrogen and phosphorus), and trace elements (iron, manganese, and zinc) from the sediment of a tropical reservoir in southeastern Brazil. Furthermore, we used bulb onions (Allium cepa) to assess the potential cytogenotoxicity of the water overlying sediments after rewetting. We found peaks in CO2 and CH4 emissions when sediments first transitioned from wet to dry, with fluxes declining as sediments dried out. CO2 emissions peaked again upon rewetting, whereas CH4 emissions remained unaltered. Our experiment also revealed average increases by up to a factor of ~5000 in the release rates of nutrients and trace elements in water overlying sediments after rewetting. These increased release rates of potentially toxic compounds likely explain the lower replication of Allium cepa cells (up to 22% reduction) exposed to water overlying sediments after rewetting. Our findings suggest that increased events of drought followed by rewetting may lead to a range of changes in freshwater ecosystems, including nutrient enrichment, increased toxicity following resuspension of contaminants, and higher emission of greenhouse gases to the atmosphere.
Polyploidy is widely recognized as a major evolutionary force in plants and has been reported in the genus
(Verbenaceae).
, the most studied species, has been documented as a polyploid complex ...involving at least four ploidal levels.
presents remarkable chemical and genetic variation and represents a model for understanding genome organization. Although the economic and medicinal importance of the species has been widely described, no established polyploid induction protocol has been reported so far. Here, we describe the production of synthetic polyploid plants of
using colchicine. The ploidal levels were estimated by flow cytometry and chromosome counting. In addition, FISH and molecular markers approaches were used to confirm the stability of the synthetic polyploids. The major component of the essential oils was estimated by GCMS to compare with the natural individuals. Tetraploids and triploids were produced providing new opportunities for investigating medicinal, pharmacological, and economic applications as well as addressing intrinsic questions involved in the polyploidization process in tropical plants.
Induction of somatic embryogenesis from in vitro-cultivated anthers represents a recent but poorly understood regeneration pathway for passion fruit species. Here, we aimed to develop an efficient ...system to produce and proliferate somatic embryos from cultivated anthers of
Passiflora cincinnata
. The floral buds were categorized into five different developmental stages (DS1 to DS5) according to their length and diameter. Their anthers were then cultured in induction medium at various concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) and 4.5 μM 6-benzyladenine. The control contained no plant growth regulators. Somatic embryogenesis started from the diploid sporophytic tissues of the anthers and continued indirectly through the formation of yellow and friable embryogenic calluses at 9.1 to 27.1 μM 2,4-D. Embryogenic calluses and primary and secondary embryos were significantly more numerous only when anthers at the DS2 stage were cultivated with 18.1 μM 2,4-D and 4.5 μM 6-benzyladenine. Secondary diploid somatic embryos formed on the surface of primary embryos via direct and repetitive embryogenesis, as well as directly from the hypocotyl of regenerated
P
.
cincinnata
emblings. The capacity to induce repetitive somatic embryogenesis represents a promising tool for
Passiflora
micropropagation.
Key message
Passion fruit anthers grown on auxin-rich medium have a high capacity for the formation and proliferation of diploid somatic embryos.
Sporadic Colorectal Cancer (sCRC) is the third leading cause of cancer death in the Western world, and the sCRC patients presenting with synchronic metastasis have the poorest prognosis. Genetic ...alterations accumulated in sCRC tumor cells translate into mutated proteins and/or abnormal protein expression levels, which contribute to the development of sCRC. Then, the tumor-associated proteins (TAAs) might induce the production of auto-antibodies (aAb) via humoral immune response. Here, Nucleic Acid Programmable Protein Arrays (NAPPArray) are employed to identify aAb in plasma samples from a set of 50 sCRC patients compared to seven healthy donors. Our goal was to establish a systematic workflow based on NAPPArray to define differential aAb profiles between healthy individuals and sCRC patients as well as between non-metastatic (n = 38) and metastatic (n = 12) sCRC, in order to gain insight into the role of the humoral immune system in controlling the development and progression of sCRC. Our results showed aAb profile based on 141 TAA including TAAs associated with biological cellular processes altered in genesis and progress of sCRC (e.g., FSCN1, VTI2 and RPS28) that discriminated healthy donors vs. sCRC patients. In addition, the potential capacity of discrimination (between non-metastatic vs. metastatic sCRC) of 7 TAAs (USP5, ML4, MARCKSL1, CKMT1B, HMOX2, VTI2, TP53) have been analyzed individually in an independent cohort of sCRC patients, where two of them (VTI2 and TP53) were validated (AUC ~75%). In turn, these findings provided novel insights into the immunome of sCRC, in combination with transcriptomics profiles and protein antigenicity characterizations, wich might lead to the identification of novel sCRC biomarkers that might be of clinical utility for early diagnosis of the tumor. These results explore the immunomic analysis as potent source for biomarkers with diagnostic and prognostic value in CRC. Additional prospective studies in larger series of patients are required to confirm the clinical utility of these novel sCRC immunomic biomarkers.
Root explants of a wild passionfruit species (
Passiflora cincinnata
) and three
P. edulis
commercial populations (‘FB 100’, ‘FB 200’, and ‘FB 300’) were incubated on Murashige and Skoog (MS) medium ...supplemented with 4.44 μM 6-benzyladenine (BA) to induce shoot organogenesis. Shoots elongated in liquid medium with 2.89 μM gibberellic acid (GA
3
) under agitation were rooted in coconut fiber and acclimatized followed by transfer to a greenhouse into pots containing mixture of coconut fiber and Plantmax
®
(1:1). Explant samples were collected during organogenesis and submitted to light and scanning electron microscopy (SEM). Root explants of
P. cincinnata
responded earlier than those of
P. edulis
. However, on the third assessment, at 90 days, the genotype ‘FB 200’ showed shoot number significantly higher than ‘FB 100’ and ‘FB 300’, not differing from
P. cincinnata
. Organogenesis in
P. cincinnata
and
P. edulis
occurred via direct pathway, which was confirmed by anatomical studies and SEM. Flow cytometric analysis revealed no variation in DNA content of regenerated plantlets among all genotypes. Nuclear DNA (2C) values (pg) in regenerants of
P. cincinnata
(2.99 pg) and
P.
edulis
(3.26–3.28 pg) were consistent with DNA amounts of seed-derived control plants.
In this study, we investigate the toxicity of commercial formulations based on glyphosate, 2,4-D, imidacloprid, and iprodione, in isolation and mixed, on
Allium cepa
. The mixtures consisted of ...combinations in the lowest (M1), intermediate (M2), and highest concentrations (M3) of each pesticide. We measured physiological (germination rate, germination speed, and radicular length) and cyto-genotoxic (mitotic index and frequency of aberrant cells) parameters. In addition, we analyzed the cell cycle progression and cell death induction by flow cytometry. When applied in isolation, the pesticides changed the parameters evaluated. M1 and M2 inhibited root length and increased the frequency of aberrant cells. Their genotoxic effect was equivalent to that of pesticides applied in isolation. Furthermore, M1 and M2 caused cell death and M2 changed the cell cycle progression. M3 had the greatest deleterious effect on
A. cepa
. This mixture inhibited root length and promoted an additive or synergistic effect on the mitotic index. In addition, M3 changed all parameters analyzed by flow cytometry. This research clearly demonstrates that the pesticides tested, and their mixtures, may pose a risk to non-target organisms.
In this study, flow cytometric analysis was used to evaluate the genetic stability of Passiflora cincinnata Mast. plants regenerated via primary and secondary somatic embryogenesis. Embryogenic calli ...obtained from culturing zygotic embryos on Murashige and Skoog (MS) medium containing 18.1 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 4.4 μM benzyladenine (BA) were transferred to differentiation medium. Torpedo and cotyledonary embryos were obtained. These primary embryos were maintained on differentiation medium to generate secondary embryos. Conversion of primary and secondary embryos yielded 305 and 138 normal plants, respectively. Almost 90% of plantlets survived following acclimatization. Flow cytometric analysis revealed that seed-derived plants had on average 3.01 pg nuclear DNA (2C), and all plants, except for a single plant regenerated via primary embryogenesis, maintained their ploidy. This single plant contained more than twice the average DNA content: 6.21 pg (4C). Epidermal stomata of leaves of the tetraploid plant were larger but lower in density than those of diploid plants, indicating that stomatal characteristics are useful in distinguishing between diploid and tetraploid plants of passion fruit. In summary, the procedure we employed to regenerated P. cincinnata plants via somatic embryogenesis generated mostly genetically true-to-type plants.
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