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1.
Bioessays ; 45(12): e2300153, 2023 12.
Artículo en Inglés | MEDLINE | ID: mdl-37987191

RESUMEN

It is necessary to complement next-generation sequencing data on the soil resistome with theoretical knowledge provided by ecological studies regarding the spread of antibiotic resistant bacteria (ARB) in the abiotic and, especially, biotic fraction of the soil ecosystem. Particularly, when ARB enter agricultural soils as a consequence of the application of animal manure as fertilizer, from a microbial ecology perspective, it is important to know their fate along the soil food web, that is, throughout that complex network of feeding interactions among members of the soil biota that has crucial effects on species richness and ecosystem productivity and stability. It is critical to study how the ARB that enter the soil through the application of manure can reach other taxonomical groups (e.g., fungi, protists, nematodes, arthropods, earthworms), paying special attention to their presence in the gut microbiomes of mesofauna-macrofauna and to the possibilities for horizontal gene transfer of antibiotic resistant genes.


Asunto(s)
Bacterias , Suelo , Animales , Bacterias/genética , Estiércol/microbiología , Cadena Alimentaria , Ecosistema , Antagonistas de Receptores de Angiotensina , Inhibidores de la Enzima Convertidora de Angiotensina , Antibacterianos/farmacología , Microbiología del Suelo , Genes Bacterianos
2.
Proc Natl Acad Sci U S A ; 119(46): e2207475119, 2022 11 16.
Artículo en Inglés | MEDLINE | ID: mdl-36343248

RESUMEN

The Ediacara Biota-the oldest communities of complex, macroscopic fossils-consists of three temporally distinct assemblages: the Avalon (ca. 575-560 Ma), White Sea (ca. 560-550 Ma), and Nama (ca. 550-539 Ma). Generic diversity varies among assemblages, with a notable decline at the transition from White Sea to Nama. Preservation and sampling biases, biotic replacement, and environmental perturbation have been proposed as potential mechanisms for this drop in diversity. Here, we compile a global database of the Ediacara Biota, specifically targeting taphonomic and paleoecological characters, to test these hypotheses. Major ecological shifts in feeding mode, life habit, and tiering level accompany an increase in generic richness between the Avalon and White Sea assemblages. We find that ∼80% of White Sea taxa are absent from the Nama interval, comparable to loss during Phanerozoic mass extinctions. The paleolatitudes, depositional environments, and preservational modes that characterize the White Sea assemblage are well represented in the Nama, indicating that this decline is not the result of sampling bias. Counter to expectations of the biotic replacement model, there are minimal ecological differences between these two assemblages. However, taxa that disappear exhibit a variety of morphological and behavioral characters consistent with an environmentally driven extinction event. The preferential survival of taxa with high surface area relative to volume may suggest that this was related to reduced global oceanic oxygen availability. Thus, our data support a link between Ediacaran biotic turnover and environmental change, similar to other major mass extinctions in the geologic record.


Asunto(s)
Evolución Biológica , Fósiles , Animales , Extinción Biológica , Biota , Océanos y Mares
3.
Ecol Lett ; 27(3): e14384, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38426584

RESUMEN

Although native species diversity is frequently reported to enhance invasion resistance, within-species diversity of native plants can also moderate invasions. While the positive diversity-invasion resistance relationship is often attributed to competition, indirect effects mediated through plant-soil feedbacks can also influence the relationship. We manipulated the genotypic diversity of an endemic species, Scirpus mariqueter, and evaluated the effects of abiotic versus biotic feedbacks on the performance of a global invader, Spartina alterniflora. We found that invader performance on live soils decreased non-additively with genotypic diversity of the native plant that trained the soils, but this reversed when soils were sterilized to eliminate feedbacks through soil biota. The influence of soil biota on the feedback was primarily associated with increased levels of microbial biomass and fungal diversity in soils trained by multiple-genotype populations. Our findings highlight the importance of plant-soil feedbacks mediating the positive relationship between genotypic diversity and invasion resistance.


Asunto(s)
Plantas , Suelo , Retroalimentación , Poaceae , Genotipo , Microbiología del Suelo , Especies Introducidas
4.
Evol Dev ; : e12491, 2024 Sep 03.
Artículo en Inglés | MEDLINE | ID: mdl-39228078

RESUMEN

Fossils of the Ediacara Biota preserve the oldest evidence for complex, macroscopic animals. Most are difficult to constrain phylogenetically, however, the presence of rare, derived groups suggests that many more fossils from this period represent extant groups than are currently appreciated. One approach to recognize such early animals is to instead focus on characteristics widespread in animals today, for example multicellularity, motility, and axial polarity. Here, we describe a new taxon, Quaestio simpsonorum gen. et sp. nov. from the Ediacaran of South Australia. Quaestio is reconstructed with a thin external membrane connecting more resilient tissues with anterior-posterior polarity, left-right asymmetry and tentative evidence for dorsoventral differentiation. Associated trace fossils indicate an epibenthic and motile lifestyle. Our results suggest that Quaestio was a motile eumetazoan with a body plan not previously recognized in the Ediacaran, including definitive evidence of chirality. This organization, combined with previous evidence for axial patterning in a variety of other Ediacara taxa, demonstrates that metazoan body plans were well established in the Precambrian.

5.
Proc Biol Sci ; 291(2023): 20240101, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38808442

RESUMEN

The early Ediacaran Weng'an biota (Doushantuo Formation, South China) provides a rare window onto the period of Earth history in which molecular timescales have inferred the initial phase of crown-metazoan diversification. Interpretation of the embryo-like fossils that dominate the biota remains contentious because they are morphologically simple and so difficult to constrain phylogenetically. Spiralicellula from the Weng'an biota is distinguished by spiral internal bodies, allied through development to Megasphaera or Helicoforamina and interpreted variously as metazoan embryos, encysting protists, or chlorophycean green algae. Here we show, using X-ray microtomography, that Spiralicellula has a single-layered outer envelope and no more than 32 internal cells, often preserving a nucleus and yolk granules. There is no correlation between the extent of spiral development and the number of component cells; rather, the spiral developed with each palintomic stage, associated with cell disaggregation and reorientation. Evidence for envelope thinning and cell loss was observed in all developmental stages, reflecting non-deterministic shedding of gametes or amoebae. The developmental biology of Spiralicellula is similar to Megasphaera and Helicoforamina, which otherwise exhibit more rounds of palintomy. We reject a crown-metazoan affinity for Spiralicellula and all other components of the Weng'an biota, diminishing the probability of crown-metazoan diversification before the early Ediacaran.


Asunto(s)
Evolución Biológica , Fósiles , Fósiles/anatomía & histología , Animales , China , Microtomografía por Rayos X , Filogenia
6.
New Phytol ; 241(6): 2575-2588, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38087806

RESUMEN

Plants can suppress the growth of other plants by modifying soil properties. These negative plant-soil feedbacks are often species-specific, suggesting that some plants possess resistance strategies. However, the underlying mechanisms remain largely unknown. Here, we investigated whether benzoxazinoids, a class of dominant secondary metabolites that are exuded into the soil by maize and other cereals, allow maize plants to cope with plant-soil feedbacks. We find that three out of five tested crop species reduce maize (Zea mays L.) performance via negative plant-soil feedbacks relative to the mean across species. This effect is partially alleviated by the capacity of maize plants to produce benzoxazinoids. Soil complementation with purified benzoxazinoids restores the protective effect for benzoxazinoid-deficient mutants. Sterilization and reinoculation experiments suggest that benzoxazinoid-mediated protection acts via changes in soil biota. Substantial variation of the protective effect between experiments and soil types illustrates context dependency. In conclusion, exuded plant secondary metabolites allow plants to cope with plant-soil feedbacks. These findings expand the functional repertoire of plant secondary metabolites and reveal a mechanism by which plants can resist negative effects of soil feedbacks. The uncovered phenomenon may represent a promising avenue to stabilize plant performance in crop rotations.


Asunto(s)
Benzoxazinas , Suelo , Benzoxazinas/farmacología , Benzoxazinas/metabolismo , Retroalimentación , Plantas/metabolismo , Zea mays/metabolismo
7.
Glob Chang Biol ; 30(4): e17283, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38663017

RESUMEN

Stratospheric ozone, which has been depleted in recent decades by the release of anthropogenic gases, is critical for shielding the biosphere against ultraviolet-B (UV-B) radiation. Although the ozone layer is expected to recover before the end of the 21st century, a hole over Antarctica continues to appear each year. Ozone depletion usually peaks between September and October, when fortunately, most Antarctic terrestrial vegetation and soil biota is frozen, dormant and protected under snow cover. Similarly, much marine life is protected by sea ice cover. The ozone hole used to close before the onset of Antarctic summer, meaning that most biota were not exposed to severe springtime UV-B fluxes. However, in recent years, ozone depletion has persisted into December, which marks the beginning of austral summer. Early summertime ozone depletion is concerning: high incident UV-B radiation coincident with snowmelt and emergence of vegetation will mean biota is more exposed. The start of summer is also peak breeding season for many animals, thus extreme UV-B exposure (UV index up to 14) may come at a vulnerable time in their life cycle. Climate change, including changing wind patterns and strength, and particularly declining sea ice, are likely to compound UV-B exposure of Antarctic organisms, through earlier ice and snowmelt, heatwaves and droughts. Antarctic field research conducted decades ago tended to study UV impacts in isolation and more research that considers multiple climate impacts, and the true magnitude and timing of current UV increases is needed.


Asunto(s)
Biota , Cambio Climático , Cubierta de Hielo , Pérdida de Ozono , Nieve , Regiones Antárticas , Animales , Rayos Ultravioleta , Estaciones del Año , Ozono Estratosférico/análisis
8.
Glob Chang Biol ; 30(8): e17483, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-39171768

RESUMEN

The role of plant biodiversity in stabilizing ecosystem multifunctionality has been extensively studied; however, the impact of soil biota biodiversity on ecosystem multifunctional stability, particularly under multiple environmental changes, remains unexplored. By conducting an experiment with environmental changes (adding water and nitrogen to a long-term grazing experiment) and an experiment without environmental changes (an undisturbed site) in semi-arid grasslands, our research revealed that environmental changes-induced changes in temporal stability of both above- and belowground multifunctionality were mainly impacted by plant and soil biota asynchrony, rather than by species diversity. Furthermore, changes in temporal stability of above- and belowground multifunctionality, under both experiments with and without environmental changes, were mainly associated with plant and soil biota asynchrony, respectively, suggesting that the temporal asynchrony of plant and soil biota has independent and non-substitutable effects on multifunctional stability. Our findings emphasize the importance of considering both above- and belowground biodiversity or functions when evaluating the stabilizing effects of biodiversity on ecosystem functions.


Asunto(s)
Biodiversidad , Pradera , Plantas , Suelo/química , Ecosistema , Microbiología del Suelo , Biota , Nitrógeno/análisis
9.
Ecol Appl ; 34(1): e2807, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36691856

RESUMEN

Many terrestrial ecosystems are co-invaded by multiple exotic species. The "invasional meltdown" hypothesis predicts that an initial invasive species will facilitate secondary invasions. In the plant kingdom, the potential underlying mechanisms of this hypothesis may be that modification of the soil properties by the initial invaders benefits for the subsequent exotic species invasion. In this study, we analyzed the composition of soil microbial communities and soil chemical properties from sites invaded by woody Rhus typhina, as well as uninvaded sites, to assess the impact of R. typhina invasion. Furthermore, we conducted a greenhouse experiment with multiple native-invasive pairs of herbaceous species to test whether R. typhina invasion facilitates subsequent exotic herb invasion. Our results showed that R. typhina invasion significantly altered the composition of soil fungal communities, especially pathogenic, endophytic, and arbuscular mycorrhizal fungi. However, this change in microbial composition led to neither direction nor magnitude changes in negative plant-soil feedback effects on both native and invasive species. This indicates that initial R. typhina invasion does not facilitate subsequent herb invasion, which does not support the "invasional meltdown" hypothesis. Additionally, R. typhina invasion significantly decreased soil total nitrogen and organic carbon contents, which may explain the significantly lower biomass of herbaceous roots grown in invaded soils compared with uninvaded soils. Alternately, although invasive herb growth was significantly more inhibited by soil microbiota compared with native herb growth, such inhibition cannot completely eliminate the risk of exotic herb invasion because of their innate growth advantages. Therefore, microbial biocontrol agents for plant invasion management should be combined with another approach to suppress the innate growth advantages of exotic species.


Asunto(s)
Microbiota , Micorrizas , Suelo/química , Micorrizas/fisiología , Madera , Biomasa , Especies Introducidas , Microbiología del Suelo
10.
Biol Lett ; 20(3): 20240042, 2024 03.
Artículo en Inglés | MEDLINE | ID: mdl-38531414

RESUMEN

Scalidophoran worms represent common infaunal components of early and middle Cambrian Burgess Shale-type fossil biotas. Early scalidophorans resemble extant priapulids based on overall morphology, but the genus Selkirkia represents the earliest record of tube dwelling for the group. Despite its ubiquitous presence in exceptional marine deposits, whether the exclusively Cambrian occurrence of Selkirkia reflects its entire evolutionary history or is affected by taphonomic biases remains unresolved. Here, we demonstrate the post-Cambrian survival of Selkirkia based on new material from the Lower Ordovician Fezouata Shale biota of Morocco. The discovery of Selkirkia in the Fezouata Shale extends the biostratigraphic range of the genus by 25 million years and its palaeobiogeographic occurrence to the high latitudes of Gondwana, strengthens the evolutionary links between Cambrian and Ordovician Burgess Shale-type biotas and increases scalidophoran diversity for the Fezouata Shale biota otherwise consisting exclusively of the palaeoscolecid Palaeoscolex? tenensis. The tube of Selkirkia underwent negligible external change for over 40 million years, indicating a high degree of morphological stasis during the Early Palaeozoic. A tubicolous mode of life is rare among extant priapulids and expressed only in Maccabeus, which forms a delicate tube from agglutinated plant debris, unlike the macroscopic secreted cuticular tube of Selkirkia.


Asunto(s)
Evolución Biológica , Fósiles , Biota
11.
Environ Sci Technol ; 2024 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-39018327

RESUMEN

This study pioneers the reporting of Se isotopes in marine top predators and represents the most extensive Se isotopic characterization in animals to date. A methodology based on hydride generation─multicollector inductively coupled plasma mass spectrometry─was established for such samples. The study was conducted on various internal organs of giant petrels (Macronectes spp.), encompassing bulk tissues (δ82/78Sebulk), distinct Se-specific fractions such as selenoneine (δ82/78SeSEN), and HgSe nanoparticles (δ82/78SeNPs). The δ82/78Sebulk results (2.0-5.6‰) offer preliminary insights into the fate of Se in key internal organs of seabirds, including the liver, the kidneys, the muscle, and the brain. Notably, the liver of all individuals was enriched in heavier Se isotopes compared to other examined tissues. In nanoparticle fraction, δ82/78Se varies significantly across individuals (δ82/78SeNPs from 0.6 to 5.7‰, n = 8), whereas it exhibits remarkable consistency among tissues and individuals for selenoneine (δ82/78SeSEN, 1.7 ± 0.3‰, n = 8). Significantly, there was a positive correlation between the shift from δ82/78Sebulk to δ82/78SeSEN and the proportion of Se present as selenoneine in the internal organs. This pilot study proves that Se species-specific isotopic composition is a promising tool for a better understanding of Se species fate, sources, and dynamics in animals.

12.
Eur J Nutr ; 63(6): 2185-2197, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38733401

RESUMEN

PURPOSE: Ulcerative colitis (UC) is a serious health problem with increasing morbidity and prevalence worldwide. The pathogenesis of UC is complex, currently believed to be influenced by genetic factors, dysregulation of the host immune system, imbalance in the intestinal microbiota, and environmental factors. Currently, UC is typically managed using aminosalicylates, immunosuppressants, and biologics as adjunctive therapies, with the risk of relapse and development of drug resistance upon discontinuation. Therefore, further research into the pathogenesis of UC and exploration of potential treatment strategies are necessary to improve the quality of life for affected patients. According to previous studies, Lactobacillus paracasei Jlus66 (Jlus66) reduced inflammation and may help prevent or treat UC. METHODS: We used dextran sulfate sodium (DSS) to induce a mouse model of UC to assess the effect of Jlus66 on the progression of colitis. During the experiment, we monitored mouse body weight, food and water consumption, as well as rectal bleeding. Hematoxylin-eosin staining was performed to assess intestinal pathological damage. Protein imprinting and immunohistochemical methods were used to evaluate the protein levels of nuclear factor-kappa B (NF-κB), mitogen-activated protein kinase (MAPK), and tight junction (TJ) proteins in intestinal tissues. Fecal microbiota was analyzed based on partial 16S rRNA gene sequencing. RESULTS: Jlus66 supplementation reduced the degree of colon tissue damage, such as colon shortening, fecal occult blood, colon epithelial damage, and weight loss. Supplementation with Jlus66 reduced DSS-induced upregulation of cytokine levels such as TNF-α, IL-1ß, and IL-6 (p < 0.05). The NF-κB pathway and MAPK pathway were inhibited, and the expression of TJ proteins (ZO-1, Occludin, and Claudin-3) was upregulated. 16S rRNA sequencing of mouse cecal contents showed that Jlus66 effectively regulated the structure of the intestinal biota. CONCLUSION: In conclusion, these data indicate that Jlus66 can alter the intestinal biota and slow the progression of UC, providing new insights into potential therapeutic strategies for UC.


Asunto(s)
Colitis Ulcerosa , Sulfato de Dextran , Modelos Animales de Enfermedad , Microbioma Gastrointestinal , Mucosa Intestinal , Lacticaseibacillus paracasei , Probióticos , Animales , Colitis Ulcerosa/microbiología , Colitis Ulcerosa/terapia , Microbioma Gastrointestinal/efectos de los fármacos , Ratones , Probióticos/farmacología , Probióticos/administración & dosificación , Lacticaseibacillus paracasei/fisiología , Mucosa Intestinal/efectos de los fármacos , Mucosa Intestinal/metabolismo , Masculino , Inflamación , Ratones Endogámicos C57BL
13.
J Appl Microbiol ; 2024 Jan 19.
Artículo en Inglés | MEDLINE | ID: mdl-38244233

RESUMEN

AIMS: The intestinal biota, known for its colonization of the human intestine and its modulation of host pathophysiological responses through the immune and endocrine systems, has gained substantial interest in recent years due to its notable correlation with diabetes and stroke. METHODS: In order to examine this association, a comparative study was conducted on the intestinal biota and blood samples obtained from mouse models and type 2 diabetic patients with and without stroke complications. Advanced techniques, such as high-throughput sequencing and enzyme-linked immunosorbent assay were employed to identify the differences in the intestinal biota and blood indices of mouse models and patients. RESULTS: At the phylum level, the dominant gut bacteria identified in patients with diabetes mellitus and stroke were Firmicutes, Bacteroidetes, and Proteobacteria. It was noteworthy that the relative abundance of Bacteroides at the genus level was significantly diminished in the DB-PT group (photothrombotic diabetes mice) as compared to the DB group (diabetesmice). This result was consistent with observations in human samples. Additionally, significant variations were detected in lipid proteins, specifically APOA4, in diabetic patients with and without stroke. CONCLUSIONS: Stroke can diminish the abundance and diversity of intestinal biota, potentially correlating with lipid proteins in patients with diabetes.

14.
Environ Res ; 262(Pt 2): 119937, 2024 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-39243840

RESUMEN

The contamination of trace elements and heavy metal(loid)s in water bodies has emerged as a global environmental concern due to their high toxicity at low concentrations to both biota and humans. This study aimed to evaluate the ecological risk associated with the occurrence and spatial distribution of Mn, Fe, Co, Cd, Ni, Zn, Sb, As, Tl, Cu, Pb, U, and V in the heavily polluted waters of an important river-reservoir system (Atoyac River Basin) in central Mexico, using two-level tired probabilistic approaches: Risk Quotient based on Species Sensitivity Distribution (RQSSD) and Joint Probability Curves (JPCs). The concentrations of these elements varied widely, ranging from 0.055 µg L-1 to 9200 µg L-1 and from 0.056 µg L-1 to 660 µg L-1, in both total and dissolved fractions, respectively. Although geogenic and anthropogenic sources contribute to the presence of these elements in waters, the discharge of untreated or poorly treated industrial wastewater is the main source of contamination. In this regard, the RQSSD results indicated high ecological risk for Mn, Fe, Co, Ni, Zn, and Sb, and medium or low ecological risk for As, Tl, U, and V at almost all sampling sites. The highest RQSSD values were found downstream of a large industrial corridor for Co, Zn, Tl, Pb, and V, with Tl, Pb, and V escalating to higher risk levels, highlighting the negative impact of industrial contamination on biota. The JPC results for these elements are consistent with the RQSSD approach, indicating an ecological risk to species from Mn, Fe, Co, Ni, Zn, and Sb in waters of the Atoyac River Basin. Therefore, the results of this study offer a thorough assessment of pollution risk, providing valuable insights for legislators on managing and mitigating exposure.

15.
Proc Natl Acad Sci U S A ; 118(40)2021 10 05.
Artículo en Inglés | MEDLINE | ID: mdl-34580216

RESUMEN

Marine dissolved organic carbon (DOC), the largest pool of reduced carbon in the oceans, plays an important role in the global carbon cycle and contributes to the regulation of atmospheric oxygen and carbon dioxide abundances. Despite its importance in global biogeochemical cycles, the long-term history of the marine DOC reservoir is poorly constrained. Nonetheless, significant changes to the size of the oceanic DOC reservoir through Earth's history have been commonly invoked to explain changes to ocean chemistry, carbon cycling, and marine ecology. Here, we present a revised view of the evolution of marine DOC concentrations using a mechanistic carbon cycle model that can reproduce DOC concentrations in both oxic and anoxic modern environments. We use this model to demonstrate that the overall size of the marine DOC reservoir has likely undergone very little variation through Earth's history, despite major changes in the redox state of the ocean-atmosphere system and the nature and efficiency of the biological carbon pump. A relatively static marine DOC reservoir across Earth's history renders it unlikely that major changes in marine DOC concentrations have been responsible for driving massive repartitioning of surface carbon or the large carbon isotope excursions observed in Earth's stratigraphic record and casts doubt on previously hypothesized links between marine DOC levels and the emergence and radiation of early animals.

16.
Proc Natl Acad Sci U S A ; 118(34)2021 08 24.
Artículo en Inglés | MEDLINE | ID: mdl-34400505

RESUMEN

The Early Cretaceous Jehol Biota is a terrestrial lagerstätte that contains exceptionally well-preserved fossils indicating the origin and early evolution of Mesozoic life, such as birds, dinosaurs, pterosaurs, mammals, insects, and flowering plants. New geochronologic studies have further constrained the ages of the fossil-bearing beds, and recent investigations on Early Cretaceous tectonic settings have provided much new information for understanding the spatiotemporal distribution of the biota and dispersal pattern of its members. Notably, the occurrence of the Jehol Biota coincides with the initial and peak stages of the North China craton destruction in the Early Cretaceous, and thus the biotic evolution is related to the North China craton destruction. However, it remains largely unknown how the tectonic activities impacted the development of the Jehol Biota in northeast China and other contemporaneous biotas in neighboring areas in East and Central Asia. It is proposed that the Early Cretaceous rift basins migrated eastward in the northern margin of the North China craton and the Great Xing'an Range, and the migration is regarded to have resulted from eastward retreat of the subducting paleo-Pacific plate. The diachronous development of the rift basins led to the lateral variations of stratigraphic sequences and depositional environments, which in turn influenced the spatiotemporal evolution of the Jehol Biota. This study represents an effort to explore the linkage between terrestrial biota evolution and regional tectonics and how plate tectonics constrained the evolution of a terrestrial biota through various surface geological processes.


Asunto(s)
Evolución Biológica , Biota , Dinosaurios/fisiología , Fósiles , Mamíferos/fisiología , Análisis Espacio-Temporal , Animales , Filogenia
17.
Radiat Environ Biophys ; 63(1): 97-107, 2024 03.
Artículo en Inglés | MEDLINE | ID: mdl-38197922

RESUMEN

Uranium mining can cause environmental impacts on non-human biota around mine sites. Because of this, the reduction in non-human biota exposure becomes an important issue. Environmental radioprotection results from the evolution of human radioprotection; it is based on dose rate to non-human biota and uses, as a biological target, and has harmful effects on populations. In the present study, a flooded impoundment created following dam construction in a uranium mine plant undergoing decommissioning was investigated. Internal dose rates due to activity concentration of natural uranium (Unat) and 232Th in omnivorous, phytophagous, and carnivorous fish species were estimated. Radionuclide activity concentrations were obtained by spectrophotometry with arsenazo III in the visible range. The dose rate contribution of 232Th was lower than that of Unat. There were no differences between the internal dose rates to studied fish species due to 232Th, but there were differences for Unat. A dose rate of 2.30·10-2 µGy∙d-1 was found due to the two studied radionuclides. Although this value falls below the benchmark for harmful effects, it is important to acknowledge that the assessment did not account for other critical radionuclides from uranium mining, which also contribute to the internal dose. Moreover, the study did not assess external doses. As a result, the possibility cannot be excluded that dose rates at the study area overcome the established benchmarks for harmful effects.


Asunto(s)
Monitoreo de Radiación , Uranio , Contaminantes Radiactivos del Agua , Animales , Torio/análisis , Uranio/análisis , Brasil , Radioisótopos , Contaminantes Radiactivos del Agua/análisis
18.
Exp Appl Acarol ; 2024 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-39088132

RESUMEN

Vegetation cover has been consistently reported to be a factor influencing soil biota. Massive spreading of invasive plants may transform native plant communities, changing the quality of habitats as a result of modification of soil properties, most often having a directional effect on soil microorganisms and soil fauna. One of the most numerous microarthropods in the litter and soil is Acari. It has been shown that invasive plants usually have a negative effect on mites. We hypothesized that invasive Spiraea tomentosa affects the structure of the Uropodina community and that the abundance and species richness of Uropodina are lower in stands monodominated by S. tomentosa than in wet meadows free of this alien species. The research was carried out in wet meadows, where permanent plots were established in an invaded and uninvaded area of each meadow, soil samples were collected, soil moisture was determined and the mites were extracted. We found that Uropodina mite communities differed in the abundance of individual species but that the abundance and richness of species in their communities were similar. S. tomentosa invasion led primarily to changes in the quality of Uropodina communities, due to an increase in the shares of species from forest and hygrophilous habitats. Our results suggest that alien plant invasion does not always induce directional changes in mite assemblages, and conclude that the impact of an alien species on Uropodina may cause significant changes in the abundance and richness of individual species without causing significant changes in the abundance and diversity of their community.

19.
Artículo en Inglés | MEDLINE | ID: mdl-39205405

RESUMEN

In the present study the concentration of selected elements in tissues of domestic rabbits and of wild brown-hares (kidneys, liver, and muscle - m. quadriceps femoris) in Slovakian habitats were determined. After mineralization the elements examined were detected using flame atomic absorption spectrophotometry/graphite furnace atomic absorption spectrophotometry. For rabbits, Fe in the liver was correlated with essential (Mn, Cu) (R2 = 0.94, p < 0.05; R2 = 0.96, p < 0.05 respectively) or toxic (Pb) elements (R2 = -0.93, p < 0.05). For hares, significant correlations were found between Cd and Cu or between Cd and Mn in the kidneys (R2 = -0.96, p < 0.05; R2 = 0.92, p < 0.05 respectively), which is the target organ for Cd. Higher concentrations of the elements were found in hare tissue, and this may be linked to pollution of their wild habitats. The xenobiotic elements as well as the essential elements were accumulated in the kidneys of the hares than rabbits. For liver, differences were less pronounced and significance was only for Fe and Cu. Muscle of hares was more contaminated than of rabbits for both biogenic and toxic elements. These results show that detectable concentrations of inorganic elements. These levels may be linked to contamination of the natural habitats of wild biota due to industry, traffic, agriculture, and urban sprawl.


Asunto(s)
Liebres , Riñón , Hígado , Animales , Conejos , Riñón/metabolismo , Riñón/química , Hígado/metabolismo , Liebres/metabolismo , Músculos/metabolismo , Músculos/química , Eslovaquia , Monitoreo del Ambiente , Espectrofotometría Atómica , Contaminantes Ambientales/análisis , Contaminantes Ambientales/metabolismo
20.
Environ Geochem Health ; 46(4): 132, 2024 Mar 14.
Artículo en Inglés | MEDLINE | ID: mdl-38483701

RESUMEN

We determined the distribution, fate, and health hazards of dimethenamid-P, metazachlor, and pyroxasulfone, the effective pre-emergence herbicides widely used both in urban and agricultural settings globally. The rate-determining phase of sorption kinetics of these herbicides in five soils followed a pseudo-second-order model. Freundlich isotherm model indicated that the herbicides primarily partition into heterogeneous surface sites on clay minerals and organic matter (OM) and diffuse into soil micropores. Principal component analysis revealed that soil OM (R2, 0.47), sand (R2, 0.56), and Al oxides (R2, 0.33) positively correlated with the herbicide distribution coefficient (Kd), whereas clay (R2, ‒ 0.43), silt (R2, ‒ 0.51), Fe oxides (R2, ‒ 0.02), alkaline pH (R2, ‒ 0.57), and EC (R2, ‒ 0.03) showed a negative correlation with the Kd values. Decomposed OM rich in C=O and C-H functional groups enhanced herbicide sorption, while undecomposed/partially-decomposed OM facilitated desorption process. Also, the absence of hysteresis (H, 0.27‒0.88) indicated the enhanced propensity of herbicide desorption in soils. Leachability index (LIX, < 0.02-0.64) and groundwater ubiquity score (GUS, 0.02‒3.59) for the soils suggested low to moderate leaching potential of the herbicides to waterbodies, indicating their impact on water quality, nontarget organisms, and food safety. Hazard quotient and hazard index data for human adults and adolescents suggested that exposure to soils contaminated with herbicides via dermal contact, ingestion, and inhalation poses minimal to no non-carcinogenic risks. These insights can assist farmers in judicious use of herbicides and help the concerned regulatory authorities in monitoring the safety of human and environmental health.


Asunto(s)
Herbicidas , Contaminantes del Suelo , Humanos , Adolescente , Suelo , Herbicidas/toxicidad , Herbicidas/análisis , Arcilla , Granjas , Contaminantes del Suelo/análisis , Adsorción , Salud Ambiental , Óxidos
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