Differential toxicity of potentially toxic elements to human gut microbes

The Concentration of Potentially Toxic Elements in Common Carp (Cyprinus carpio) Fish: Systematic Review and Meta-Analysis and Dietary Health Risk Assessment

Common carp (Cyprinus carpio) is one of the most consumed fish in the world and can be exposed to various forms of pollution, such as potential toxic elements (PTEs). Several studies have been conducted on the concentration of PTEs in common carp fish. The aims of the current study were to meta-analyze the concentration of PTEs in common carp fish and estimate human health risks in consumers. A search was conducted in international databases, including Scopus, PubMed, Science Direct, Web of Science, and Embase to retrieve papers up to January 20, 2024. The non-carcinogenic risk due to PTEs in fish fillets was calculated via the target hazard quotient (THQ), and the carcinogenic risk due to iAs in fish fillets was calculated via cancer risk (CR). The highest concentrations of Cu, methyl-Hg, and Ni were observed in the fillets of common carp fish. The non-carcinogenic risk was lower than 1 in all countries; hence, consuming common carp fish does not pose a non-carcinogenic risk. Adult consumers in Iraq were exposed to an unacceptable carcinogenic due to iAs in common carp fish. Hence, it is recommended that plans be conducted to reduce the concentration of PTEs in common carp fish in Iraq.

The role of heavy metal exposure on the microbiome in the etiology of gastrointestinal disorders: a scoping review

In recent years, epidemiological studies have increasingly recognized the significance of heavy metals as an important pathogenetic factor in many gastrointestinal diseases, particularly those associated with in gut microbiota functions. The toxicity of heavy metals towards essential intestinal microflora goes beyond causing dysbiotic disorders; it can also exacerbate intestinal infections, alter metabolic processes, and influence the development of antibiotic resistance. Since the negative effects of heavy metals are environmental in nature, there is a need to systematize the etiological role between the effects of heavy metals on the microbiome and possible nosological conditions for a more accurate approach to treatment and further research. Given the environmental origins of the abovementioned effects, there is a need to systematize the impact of heavy metals on the microbiome and their role in disease development to improve approaches to treatment and further research. We aimed to analyze the latest scientific evidence on the associations between heavy metals exposure and the intestinal microbiome and its role in the development of gastrointestinal disorders. For this scoping review we used PubMed and eLIBRARY.ru databases. We searched for keywords: «gut microbiota», «intestinal infections» (disorders), «antibiotic resistance» «heavy metals» in both Russian and English. Based on the research reviewed in this study, we can infer that heavy metals act as exogenous toxicants contributing to the development of dysbiotic, metabolic and trophic disorders of the gastrointestinal tract. They also influence the progression of infections and the development of antibiotic resistance in bacteria. Further studies should focus on exploring the toxicity of heavy metals in relation to specific populations of intestinal flora and associations with metal and antibiotic resistance. It is important to consider the therapeutic potential of microbiome modulation in the management of gastrointestinal diseases.

Potential use of seaweed polysaccharides as prebiotics for management of metabolic syndrome: a review

Seaweed polysaccharides (SPs) obtained from seaweeds are a class of functional prebiotics. SPs can regulate glucose and lipid anomalies, affect appetite, reduce inflammation and oxidative stress, and therefore have great potential for managing metabolic syndrome (MetS). SPs are poorly digested by the human gastrointestinal tract but are available to the gut microbiota to produce metabolites and exert a series of positive effects, which may be the mechanism by which SPs render their anti-MetS effects. This article reviews the potential of SPs as prebiotics in the management of MetS-related metabolic disturbances. The structure of SPs and studies related to the process of their degradation by gut bacteria and their therapeutic effects on MetS are highlighted. In summary, this review provides new perspectives on SPs as prebiotics to prevent and treat MetS.

Integration of leave-one-out method and real-time live cell reporter array system to assess the toxicity of mixtures

The ever-increasing number of chemicals and complex mixtures demands a time-saving and cost-effective platform for environmental risk assessment. However, there is limit promising tool for evaluating the contribution of each component to the total toxicity effects of the mixture. Here, four widely distributed environmental pollutants with different mode-of-actions, i.e., cadmium chloride (Cd), nitrofurazone (NFZ), triclosan (TCS), and tris(2-chloroethyl) phosphate (TCEP), were selected as components of artificial mixture. Integration of leave-one-out method and high-dimensional live cell array system was used to explore relative contribution of each component from the mixture. A quaternary mixture (All_4_chems) and four ternary mixtures (Leave_Cd, Leave_NFZ, Leave_TCS and Leave_TCEP) were investigated by Escherichia coli (E. coli) live cell array system with 90 environmental stress genes modified by green fluorescent protein (GFP) expressing reporter vectors. E. coli cytotoxicity tests demonstrated that TCS has antagonism effect with other three chemicals (Cd, NFZ and TCEP), while it was additive effect in other three binary combinations. A total of 26, 23, 13, 31 and 23 genes were significantly altered with fold-change greater than 2 over the 4 h exposure by All_4_chems, Leave_Cd, Leave_NFZ, Leave_TCS and Leave_TCEP, respectively. Clustering analysis based on time-series gene expression patterns and transcriptional effect level index (TELI) showed that Leave_TCEP has similar profiles with All_4_chems, demonstrating TCEP has the least contribution among four components to the quaternary mixture. Leave_NFZ has the least number of significantly altered genes, implying NFZ has the largest toxicity effect contribution to the quaternary mixture. The relative contribution in different pathways indicated that Cd has the most contribution to the mixture in redox stress, while TCS has the least contribution in DNA stress pathway. Collectively, our results demonstrated the utility of high-dimensional toxicogenomics data and leave-one-out method in prioritizing the relative contribution of each component in mixture.

Hg Pollution Indices along the Reis Magos River Basin-Brazil: A Precursory Study

Mercury is a metal present in the Earth's crust, but due to human contribution, its concentration can increase, causing environmental impacts to aquatic ecosystems, among others. The Reis Magos River Hydrographic Basin represents economic and socio-environmental importance for the state of Espírito Santo, Brazil. However, there are not many publications regarding the quality of water and sediments, so no data is reported concerning the total concentration of Hg. Thus, the present work aimed to evaluate the distribution of total Hg in water and sediments along this hydrographic basin. For a better inference, physicochemical parameters of the water were determined (temperature, pH, electrical conductivity, oxidation-reduction potential (ORP), turbidity, dissolved oxygen (DO), total dissolved solids (TDS), and salinity), and in the sediments, the contents of matter organic matter, pH, carbonates and granulometry. Mercury determination was performed by Thermodecomposition and Amalgamation Atomic Absorption Spectrometry (TDA AAS) with a DMA-80 spectrometer. The Hg determined in the water was lower than the limit of quantification, 0.14 µg∙L^-1, which is lower than the maximum limits recommended by world reference environmental agencies. In the sediment samples, the Hg found were below 170 µg∙kg^-1, values below which there is less possibility of an adverse effect on the biota. However, when the degree of anthropic contribution was evaluated using the Geoaccumulation index (IGeo), the contamination factor (CF), and the ecological risk potential index (E_F), there was evidence of moderate pollution. Thus, this highlighted the need for monitoring the region since climatic variations and physical-chemical parameters influence the redistribution of Hg between the water/sediment interface.