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Abstract: The major weakness of the current in vitro genotoxicity test systems is the inability of the indicator cells to express metabolic enzymes needed for the activation and detoxification of genotoxic compounds, which consequently can lead to misleading results. Thus, there is a significant emphasis on developing hepatic cell models, including advanced in vitro three-dimensional (3D) cell-based systems, which better imitate in vivo cell behaviour and offer more accurate and predictive data for human exposures. In this study, we developed an approach for genotoxicity testing with 21-day old spheroids formed from human hepatocellular carcinoma cells (HepG2/C3A) using the dynamic clinostat bioreactor system (CelVivo BAM/bioreactor) under controlled conditions. The spheroids were exposed to indirect-acting genotoxic compounds, polycyclic aromatic hydrocarbon [PAH; benzo(a) pyrene B(a)P], and heterocyclic aromatic amine [PhIP]) at non-cytotoxic concentrations for 24 and 96 h. The results showed that both environmental pollutants B(a)P and PhIP significantly increased the level of DNA strand breaks assessed by the comet assay. Further, the mRNA level of selected genes encoding metabolic enzymes from phase I and II, and DNA damage responsive genes was determined (qPCR). The 21-day old spheroids showed higher basal expression of genes encoding metabolic enzymes compared to monolayer culture. In spheroids, B(a)P or PhIP induced compound-specific up-regulation of genes implicated in their metabolism, and deregulation of genes implicated in DNA damage and immediate-early response. The study demonstrated that this model utilizing HepG2/C3A spheroids grown under dynamic clinostat conditions represents a very sensitive and promising in vitro model for genotoxicity and environmental studies and can thus significantly contribute to a more reliable assessment of genotoxic activities of pure chemicals, and complex environmental samples even at very low for environmental exposure relevant concentrations.
Keywords: in vitro 3D cell model, 21-day old spheroids, cytotoxic, genotoxic, gene expression
Published in DiRROS: 19.07.2024; Views: 227; Downloads: 216
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Abstract: TGA (TGACG-binding) transcription factors, which bind their target DNA through a conserved basic region leucine zipper (bZIP) domain, are vital regulators of gene expression in salicylic acid (SA)-mediated plant immunity. Here, we investigated the role of StTGA2.1, a potato (Solanum tuberosum) TGA lacking the full bZIP, which we named a mini-TGA. Such truncated proteins have been widely assigned as loss-of-function mutants. We, however, confirmed that StTGA2.1 overexpression compensates for SA-deficiency, indicating a distinct mechanism of action compared with model plant species. To understand the underlying mechanisms, we showed that StTGA2.1 can physically interact with StTGA2.2 and StTGA2.3, while its interaction with DNA was not detected. We investigated the changes in transcriptional regulation due to StTGA2.1 overexpression, identifying direct and indirect target genes. Using in planta transactivation assays, we confirmed that StTGA2.1 interacts with StTGA2.3 to activate StPRX07, a member of class III peroxidases (StPRX), which are known to play role in immune response. Finally, via structural modeling and molecular dynamics simulations, we hypothesized that the compact molecular architecture of StTGA2.1 distorts DNA conformation upon heterodimer binding to enable transcriptional activation. This study demonstrates how protein truncation can lead to distinct functions and that such events should be studied carefully in other protein families.
Published in DiRROS: 18.07.2024; Views: 391; Downloads: 158
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Abstract: Historical biogeography is an integrative scientific field critical for testing evolutionary hypotheses pertinent to organismal distributions, but despite recent theoretical and analytical advances, biogeographic reconstructions continue to struggle with accuracy and rigor. Most modern studies include the three elements needed for historical biogeographic inference, namely a time-calibrated phylogeny, contemporary taxonomic distributions, and estimations of organismal dispersal probabilities. The latter, we argue, are particularly vague, and historical biogeography would greatly benefit from dispersal probability estimations that are better informed and biologically meaningful. To achieve that goal, next-generation biogeography should ideally consider: a) dispersal-related traits; b) ecology; c) geological histories; and d) geographical factors. We briefly recap the three case studies on spiders that have pioneered this approach. Due to their old age and mega-diversity—considering both phylogenetic and life style diversity—arachnids are an ideal animal lineage for modern biogeographic research. There is no reason, however, that the concept should not be applied to all life. Further modifications of the proposed concept and, particularly, methodological implementation are needed to render this biogeographic framework widely useful.
Keywords: next-generation biogeography, ancestral areas, dispersal biology, geological history, vicariance, extinction, arachnids
Published in DiRROS: 18.07.2024; Views: 258; Downloads: 127
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Abstract: The assemblages of marine benthic organisms and sediment characteristics were investigated in the coastal area between the Mario Zucchelli Antarctic Research Station and Adelie Cove in Terra Nova Bay (Ross Sea, Southern Ocean) during the 2015 summer season. Sediment samples were taken from 11 stations at depths between 25 and 140 m. The dominance of sand characterised sites, and the biochemical composition of the sedimentary organic matter resulted in very variable between the different sites. A total of 142 taxa were identified, with Annelida (68 taxa) and Arthropoda (35 taxa) constituting the main macrobenthic groups. The benthic community at deeper stations showed higher species richness and lower dominance compared to the shallower stations. For the first time in Antarctica, we also investigated the response of the AZTI’s Marine Biotic Index (AMBI) to the organic gradient. Of the 142 taxa found, 97 were not listed in the AMBI library, and we were able to assign as many as 88 taxa to an ecological group. All of these new species were added to the new AMBI species list. AMBI showed a good response to the organic gradient.
Keywords: antarctic benthos, ecological quality assessment, indexes, Ross Sea
Published in DiRROS: 18.07.2024; Views: 291; Downloads: 223
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Abstract: This perspective identifies the grand challenges in arachnid science: 1. Grasp the arachnid species diversity. There is a need to accelerate taxonomic research to obtain a sense of arachnid species diversity, however, at the same time, taxonomy needs to increase its quality, rigor, and repeatability. 2. Standardize arachnid systematics research. A solid phylogenetic definition and morphological diagnosis of Arachnida and its composing subgroups, usually treated at the rank of order, are needed. Studies should aim to stabilize and standardize phylogenetic efforts at all levels of hierarchy, and systematists should adopt criteria for higher level ranks in arachnid classification. 3. Interpret arachnid trait evolution through omics approaches. Among the field’s grand challenges is to define the genetic diversity encoding for the diverse arachnid traits, including developmental, morphological and ecological characteristics, biomaterials such as silks, venoms, digestive fluids, or allergens and bioproducts that cause diseases. Comparative genomics, transcriptomics, and proteomics will provide the empirical basis for biotechnology to modify arachnid genomes to fit numerous applications. 4. Facilitate biotechnological applications of arachnid molecules and biomaterials. Among the grand field challenges is to define potential applications of arachnid bioproducts from therapeutics to industry. New natural and biodegradable products, e.g. from spider silks, should ease our burden on ecosystems. 5. Utilize arachnids as models in ecological and biogeographic research. Biodiversity inventory sampling and analytical techniques should be extended from spiders to other arachnid groups. Spiders and their webs could be used as environmental DNA samplers, measuring or monitoring ecosystems’ overall biodiversity. Arachnids are excellent models to address biogeographical questions at the global to local scales. 6. Disentangle evolutionary drivers of arachnid diversity. Among the field grand challenges is a more precise evaluation to what extent the emergence of arachnid phenotypes is shaped by classical selection processes, and under what conditions, if any, sexual conflict needs to be invoked. 7. Define effective conservation measures for arachnids in the light of global changes. Effective conservation measures in arachnology should integrate the data from phylogenetic diversity, physiology, ecology, biogeography, and global change biology.
Keywords: diversity, systematics, arachnids, evolution, biomaterials
Published in DiRROS: 18.07.2024; Views: 260; Downloads: 132
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