An energy coupling factor transporter of Streptococcus sanguinis impacts antibiotic susceptibility as well as metal and membrane homeostasis.

Streptococcus sanguinis is a prevalent member of human microbiome capable of acting as a causative agent of oral and respiratory infections. S. sanguinis competitive success within the infection niche is dependent on acquisition of metal ions and vitamins. Among the systems that bacteria use for micronutrient uptake is the energy coupling factor (ECF) transporter system EcfAAT. Here we describe physiological changes arising from EcfAAT transporter disruption. We found that EcfAAT contributes to S. sanguinis antibiotic sensitivity as well as metal and membrane homeostasis. Specifically, our work found that disruption of EcfAAT results in increased polymyxin susceptibility. We performed assessment of cell-associated metal content and found depletion of iron, magnesium, and manganese. Furthermore, membrane composition analysis revealed significant enrichment in unsaturated fatty acid species resulting in increased membrane fluidity. Our results demonstrate how disruption of a single EcfAAT transporter can have broad consequences on bacterial cell homeostasis. ECF transporters are of interest within the context of infection biology in bacterial species other than streptococci, hence work described here will further the understanding of how micronutrient uptake systems contribute to bacterial pathogenesis.

Cytotoxic effects and comparative analysis of Ni ion uptake by osteoarthritic and physiological osteoblasts.

Nickel(Ni)-containing materials have been widely used in a wide range of medical applications, including orthopaedics. Despite their excellent properties, there is still a problem with the release of nickel ions into the patient's body, which can cause changes in the behaviour of surrounding cells and tissues. This study aims to evaluate the effects of Ni on bone cells with an emphasis on the determination of Ni localization in cellular compartments in time. For these purposes, one of the most suitable models for studying the effects induced by metal implants was used-the patient's osteoarthritic cells. Thanks to this it was possible to simulate the pathophysiological conditions in the patient's body, as well as to evaluate the response of the cells which come into direct contact with the material after the implantation of the joint replacement. The largest differences in cell viability, proliferation and cell cycle changes occurred between Ni 0.5 mM and 1 mM concentrations. Time-dependent localization of Ni in cells showed that there is a continuous transport of Ni ions between the nucleus and the cytoplasm, as well as between the cell and the environment. Moreover, osteoarthritic osteoblasts showed faster changes in concentration and ability to accumulate more Ni, especially in the nucleus, than physiological osteoblasts. The differences in Ni accumulation process explains the higher sensitivity of patient osteoblasts to Ni and may be crucial in further studies of implant-derived cytotoxic effects.

Trace metals in the teleost fish gill: biological roles, uptake regulation, and detoxification mechanisms.

In fish, the gill plays a vital role in regulating the absorption of trace metals and is also highly susceptible to metal toxicity. Trace metals such as iron (Fe), copper (Cu), zinc (Zn), and manganese (Mn) are involved in various catalytic activities and molecular binding within the gill, thereby supporting a range of physiological processes in this organ. While beneficial at normal levels, these metals can become toxic when present in excess. Conversely, nonessential metals like cadmium (Cd) and lead (Pb) can gain entry into gill cells through similar metal transport pathways, potentially interfering with various cellular processes. The transepithelial transport of these metals across the gill epithelium is governed by a variety of metal transport and metal binding proteins. These include the Cu transporter 1 (CTR1), divalent metal transporter 1 (DMT1), and members of the Zrt-/Irt-like protein (ZIP) and zinc transport (ZnT) families. Additionally, some of these metals can compete with major ions (e.g., calcium, sodium) for absorption sites in the gill. This complex crosstalk suggests an interdependent mechanism that balances metal uptake to meet physiological needs while preventing excessive accumulation. In this article, I review the roles of trace metals in proteins/enzymes that support the different functions in the gill of teleost fish. I also discuss current understanding of the pathways involved in regulating the branchial uptake of metals and their influence on ionic regulation, and the potential detoxification mechanisms in the gill. Finally, I summarize knowledge gaps and potential areas for further investigation.

Manganese uptake by MtsABC contributes to the pathogenesis of human pathogen group A streptococcus by resisting host nutritional immune defenses.

The interplay between host nutritional immune mechanisms and bacterial nutrient uptake systems has a major impact on the disease outcome. The host immune factor calprotectin (CP) limits the availability of essential transition metals, such as manganese (Mn) and zinc (Zn), to control the growth of invading pathogens. We previously demonstrated that the competition between CP and the human pathogen group A streptococcus (GAS) for Zn impacts GAS pathogenesis. However, the contribution of Mn sequestration by CP in GAS infection control and the role of GAS Mn acquisition systems in overcoming host-imposed Mn limitation remain unknown. Using a combination of in vitro and in vivo studies, we show that GAS-encoded mtsABC is a Mn uptake system that aids bacterial evasion of CP-imposed Mn scarcity and promotes GAS virulence. Mn deficiency caused by either the inactivation of mtsC or CP also impaired the protective function of GAS-encoded Mn-dependent superoxide dismutase. Our ex vivo studies using human saliva show that saliva is a Mn-scant body fluid, and Mn acquisition by MtsABC is critical for GAS survival in human saliva. Finally, animal infection studies using wild-type (WT) and CP-/- mice showed that MtsABC is critical for GAS virulence in WT mice but dispensable in mice lacking CP, indicating the direct interplay between MtsABC and CP in vivo. Together, our studies elucidate the role of the Mn import system in GAS evasion of host-imposed metal sequestration and underscore the translational potential of MtsABC as a therapeutic or prophylactic target.

Combined application of zinc oxide and iron nanoparticles enhanced Red Sails lettuce growth and antioxidants enzymes activities while reducing the chromium uptake by plants grown in a Cr-contaminated soil.

Soil contamination with chromium (Cr) is becoming a primary ecological and health concern, specifically in the Kasur and Sialkot regions of Pakistan. The main objective of the current study was to evaluate the impact of foliar application of zinc oxide nanoparticles (ZnO NPs) (0, 25, 50, 100 mg L-1) and Fe NPs (0, 5, 10, 20 mg L-1) in red sails lettuce plants grown in Cr-contaminated soil. Our results showed that both ZnO and Fe NPs improved plant growth, and photosynthetic attributes by minimizing oxidative stress in lettuce plants through the stimulation of antioxidant enzyme activities. At ZnO NPs (100 mgL-1), dry weights of shoots and roots and fresh weights of shoots and roots were improved by 53%, 58%, 34%, and 45%, respectively, as compared to the respective control plants. The Fe NPs treatment (20 mgL-1) increased the dry weight of shoots and the roots and fresh weights of shoots and roots by 53%, 76%, 42%, and 70%, respectively. Application of both NPs reduced the oxidative stress caused by Cr, as evident by the findings of the current study, i.e., at the ZnO NPs (100 mgL-1) and Fe NPs (20 mgL-1), the EL declined by 32% and 44%, respectively, in comparison with respective control plants. Moreover, Fe and ZnO NPs enhanced the Fe and Zn contents in red sails lettuce plants. Application of ZnO NPs at 100 mg L-1 and Fe NPs at 20 mg L-1, improved the Zn and Fe contents in plant leaves by 86%, and 68%, respectively, as compared to the control plants. This showed that the exogenous application of these NPs helped in Zn and Fe fortification in plants. At similar of concenteration ZnO NPs, CAT and APX activities were improved by 52% and 53%, respectively. Similarly, the POD contents were improved by 17% and 45% at 5 and 10 mg/L of Fe NPs. Furthermore, ZnO and Fe NPs limited the Cr uptake by plants, and the concentration of Cr in the leaves of lettuce was under the threshold limit. The exogenous application of ZnO NPs (100 mg L-1) and Fe NPs (20 mg L-1) reduced the Cr uptake in the leaves of red sails lettuce by 57% and 51%, respectively. In conclusion, ZnO and Fe NPs could be used for the improvement of plant growth and biomass as well as nutrient fortification in stressed environments. These findings not only underscore the efficacy of nanoparticle-assisted phytoremediation but also highlight its broader implications for sustainable agriculture and environmental health. However, future studies on other crops with molecular-level investigations are recommended for the validation of the results.

ZnO and Fe NPs improved the growth and photosynthesis of red sails lettuce plantsBoth NPs enhanced antioxidants enzymes activities in stressed plantsNPs mediated response reduced the oxidative stress and Cr uptake in red sails lettuceZnO and Fe NPs resulted in Zn and Fe fortification, respectively, in red sails lettuce.

Symplasmic and transmembrane zinc transport is modulated by cadmium in the Cd/Zn hyperaccumulator Sedum alfredii.

This study investigated the influence of Cd (25 µM) on Zn accumulation in a hyperaccumulating (HE) and a non-hyperaccumulating (NHE) ecotype of Sedum alfredii Hance at short-term supply of replete (Zn5, 5 µM) and excess (Zn400, 400 µM) Zn. Cd inhibited Zn accumulation in both ecotypes, especially under Zn400, in organs with active metal sequestration, i.e. roots of NHE and shoots of HE. Direct biochemical Cd/Zn competition at the metal-protein interaction and changes in transporter gene expression contributed to the observed accumulation patterns in the roots. Specifically, in HE, Cd stimulated SaZIP4 and SaPCR2 under Zn5, but downregulated SaIRT1 and SaZIP4 under Zn400. However, Cd downregulated related transporter genes, except for SaNRAMP1, in NHE, irrespective of Zn. Cadmium stimulated casparian strip (CSs) development in NHE, as part of the defense response, while it had a subtle effect on the (CS) in HE. Moreover, Cd delayed the initiation of the suberin lamellae (SL) in HE, but stimulated SL deposition in NHE under both Zn5 or Zn400. Changes in suberization were mainly ascribed to suberin-biosynthesis-related genes and hormonal signaling. Altogether, Cd regulated Zn accumulation mainly via symplasmic and transmembrane transport in HE, while Cd inhibited both symplasmic and apoplasmic Zn transport in NHE.

The Role of Sediment Ingestion in Exposing Bottom-Feeding Fish to Chemical Elements.

Digesta were collected from the intestines of seven species of bottom-feeding fish to better understand the role of incidental ingestion of sediment in exposing fish to inorganic contaminants. A composite sediment tracer variable, based on concentrations of Co, Cr, Ni, Ti, V, and Y in digesta and in sediment, was calculated to estimate sediment content of digesta. Concentration factors (mg/kg in digesta divided by mg/kg in sediment) of eight elements of interest were linearly regressed on this tracer variable. The relative importance of sediment ingestion to oral exposure was quantified. Zinc, Cd, and Cu were ingested mainly from sediment-free food. Arsenic, Cr, Ni, Al, and Pb, in contrast, were ingested mainly from sediment. As an example, 93% of the Ni in digesta from a brown bullhead (Ameiurus nebulosus) was from sediment and only 7% from food. Regressions of Al and Pb in digesta of suckers (Catostomidae) suggested an additional oral source, possibly from oxides coating biotic or abiotic surfaces. Overall, concentrations of 12 of 21 elements studied were positively correlated with sediment content (p < 0.005). Including sediment ingestion as a pathway for bottom-feeding fish is essential for accurately estimating exposures in toxicological studies. Environ Toxicol Chem 2024;43:1036-1046. Published 2024. This article is a U.S. Government work and is in the public domain in the USA.

Entrapment of atmospheric particle bound heavy metals by ferns as evidenced by lead (Pb) isotope and MixSIAR: Implications for improving air quality.

Plant metal uptake can occur through both soil-root and atmospheric transfer from leaves. The latter holds potential implications for development of biofiltration systems. To explore this potential, it is crucial to understand entrapment capacity and metal sources within plants. As ferns absorb materials from atmosphere, this study focuses on two abundant fern species growing in densely populated and highly polluted regions of Eastern India. Gravimetric quantification, elemental concentration and Pb isotopic analyses were performed by segregating the ferns into distinct components: foliage dusts (loose dust (LD) and wax-bound dust (WD)) and plant tissue (leaves and roots). To understand metal sources, the study analyzes soil, and atmospheric particulates (PM10 and dust fall (DF)). Results indicate that, while LDs have soil dust influence, wax entraps atmospheric particulates and translocates them inside the leaves. Furthermore, roots demonstrate dissimilar isotopic ratios from soil, while displaying close association with atmospheric particulates. Isotopic composition and subsequent mixing model reveal dominant contribution from DF in leaves (53-73%) and roots (33-86%). Apart from DF, leaf Pb is sourced from PM10 (21-38%) with minimal contribution from soil (6-10%). Conversely, in addition to dominance from DF, roots source Pb primarily from soil (12-62%) with a meagre 2-8% contribution from PM10.

A cobalt concentration sensitive Btu-like system facilitates cobalamin uptake in Anabaena sp. PCC 7120.

Metal homeostasis is central to all forms of life, as metals are essential micronutrients with toxic effects at elevated levels. Macromolecular machines facilitate metal uptake into the cells and their intracellular level is regulated by multiple means, which can involve RNA elements and proteinaceous components. While the general principles and components for uptake and cellular content regulation of, e.g., cobalt have been identified for proteobacteria, the corresponding mechanism in other Gram-negative bacteria such as cyanobacteria remain to be established. Based on their photosynthetic activity, cyanobacteria are known to exhibit a special metal demand in comparison to other bacteria. Here, the regulation by cobalt and cobalamin as well as their uptake is described for Anabaena sp. PCC 7120, a model filamentous heterocyst-forming cyanobacterium. Anabaena contains at least three cobalamin riboswitches in its genome, for one of which the functionality is confirmed here. Moreover, two outer membrane-localized cobalamin TonB-dependent transporters, namely BtuB1 and BtuB2, were identified. BtuB2 is important for fast uptake of cobalamin under conditions with low external cobalt, whereas BtuB1 appears to function in cobalamin uptake under conditions of sufficient cobalt supply. While the general function is comparable, the specific function of the two genes differs and mutants thereof show distinct phenotypes. The uptake of cobalamin depends further on the TonB and a BtuFCD machinery, as mutants of tonB3 and btuD show reduced cobalamin uptake rates. Thus, our results provide novel information on the uptake of cobalamin and the regulation of the cellular cobalt content in cyanobacteria.

Effect of riboflavin on redox balance, osmolyte accumulation, methylglyoxal generation and nutrient acquisition in indian squash (Praecitrullus fistulosus L.) under chromium toxicity.

The presence of high chromium (Cr) levels induces the buildup of reactive oxygen species (ROS), resulting in hindered plant development. Riboflavin (vitamin B2) is produced by plants, fungi, and microbes. It serves as a precursor to the coenzymes flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN), which play a crucial role in cellular metabolism. The objective of this work was to clarify the underlying mechanisms by which riboflavin alleviates Cr stress in Praecitrullus fistulosus L. Further, the role of riboflavin in growth, ions homeostasis, methylglyoxal detoxification, and antioxidant defense mechanism are not well documented in plants under Cr toxicity. We found greater biomass and minimal production of ROS in plants pretreated with riboflavin under Cr stress. Results manifested a clear abridge in growth, chlorophyll content, and nutrient uptake in Indian squash plants exposed to Cr stress. Findings displayed that Cr stress visibly enhanced oxidative injury reflected as higher malondialdehyde (MDA), hydrogen peroxide (H2O2), superoxide radical (O2•‒), methylglyoxal (MG) levels alongside vivid lipoxygenase activity. Riboflavin strengthened antioxidant system, enhanced osmolyte production and improved membrane integrity. Riboflavin diminished Cr accumulation in aerial parts that led to improved nutrient acquisition. Taken together, riboflavin abridged Cr phytotoxic effects by improving redox balance because plants treated with riboflavin had strong antioxidant system that carried out effective ROS detoxification. Riboflavin protected membrane integrity that, in turn, improved nutrient uptake in plants.

Histopathological effects of long-term exposure to realistic concentrations of cadmium in the hepatopancreas of Sparus aurata juveniles.

In recent decades, cadmium has emerged as an environmental stressor in aquatic ecosystems due to its persistence and toxicity. It can enter water bodies from various natural and anthropogenic sources and, once introduced into aquatic systems, can accumulate in sediments and biota, leading to bioaccumulation and biomagnification in the food chain. For this reason, the effects of cadmium on aquatic life remain an area of ongoing research and concern. In this paper, a multidisciplinary approach was used to assess the effects of long-term exposure to an environmental concentration on the hepatopancreas of farmed juveniles of sea bream, Sparus aurata. After determining metal uptake, metallothionein production was assessed to gain insight into the organism's defence response. The effects were also assessed by histological and ultrastructural analyses. The results indicate that cadmium accumulates in the hepatopancreas at significant concentrations, inducing structural and functional damage. Despite the parallel increase in metallothioneins, fibrosis, alterations in carbohydrate distribution and endocrine disruption were also observed. These effects would decrease animal fitness although it did not translate into high mortality or reduced growth. This could depend on the fact that the animals were farmed, protected from the pressure deriving from having to search for food or escape from predators. Not to be underestimated is the return to humans, as this species is edible. Understanding the behaviour of cadmium in aquatic systems, its effects at different trophic levels and the potential risks to human health from the consumption of contaminated seafood would therefore be essential for informed environmental management and policy decisions.

Metal toxicity in Bryum coronatum Schwaegrichen: impact on chlorophyll content, lamina cell structure, and metal accumulation.

This research examined the impact of heavy metals, including Cd, Pb, and Zn, on chlorophyll content and lamina cell structure in Bryum coronatum. After exposure to varying metal concentrations (0.015, 0.065, 0.250, 1, and 4 mg/L), chlorophyll content, chloroplast numbers, lamina cell change, and metal accumulation were investigated. Chlorophyll content was assessed using spectrophotometry, whereas chloroplast numbers and lamina cell changes were examined under a light microscope. Metal accumulation was quantified through ICP-MS. The findings revealed that Cd notably reduced chlorophyll a content, while Pb and Zn showed minimal influence. Cd and Pb exposure decreased the number of chloroplasts in lamina cells, with no impact from Zn. The moss's capacity to absorb metals increased with higher exposure levels, indicating its potential as a biomonitor for heavy metal pollution. Cell mortality occurred in response to Cd and Pb, primarily in the median and apical lamina regions, while Zn had no effect. This study sheds light on heavy metal toxicity in B. coronatum, underscoring its significance for environmental monitoring. Further research on the mechanisms and consequences of heavy metal toxicity in bryophytes is essential for a comprehensive understanding of this critical issue.

The capacity of moss B. coronatum to absorb metals increased with higher exposure levels, providing quantitative data on heavy metal pollution around it.

Two TonB-dependent outer membrane transporters involved in heme uptake in Anabaena sp. PCC 7120.

Low availability of micronutrients such as iron has enforced the evolution of uptake systems in all kingdoms of life. In Gram-negative bacteria, outer membrane, periplasmatic and plasma membrane localized proteins facilitate the uptake of iron-loaded chelators, which are energized by TonB proteins. The specificity of different uptake systems likely depends either on the endogenously produced siderophore or on the bioavailability of iron-chelator complexes in the environment. Hence, an uptake system for schizokinen produced by the model cyanobacterium Anabaena sp. PCC 7120 exists, while bioinformatics analysis suggests the existence of additional systems, likely for uptake of xenosiderophores. Consistently, proteins encoded by alr2153 (hutA1) and alr3242 (hutA2) are assigned as outer membrane heme transporters. Indeed, Anabaena sp. PCC 7120 can utilize external heme as an iron source. The addition of heme resulted in an induction of genes involved in heme degradation and chlorophyll a synthesis and in an increase of the chlorophyll a content. Moreover, iron starvation induced the expression of hutA1, while the addition of heme led to its repression. Remarkably, the addition of a high concentration of heme but not iron starvation resulted in hutA2 induction. Plasmid insertion mutants of both genes exhibited a reduced capacity to recover from iron starvation by heme addition, which indicates a dependence of heme uptake on functional HutA1 and HutA2 proteins. The structural model generated by bioinformatics methods is further in agreement with a role in heme uptake. Thus, we provide evidence that Anabaena sp. PCC 7120 uses a heme uptake system in parallel to other iron acquisition systems.

Sorption of cadmium, chromium, lead, and vanadium from artificial wetlands using Lemna aequinoctialis.

The efficacy of the lesser duckweed, Lemna aequinoctialis (Welw.), to remediate varying concentrations of cadmium, chromium, lead, and vanadium from an organo-metallic contaminated media was tested in artificial surface wetland mesocosm experiment. A 100 g of fresh-weight duckweed was introduced into each of the mesocosm, except for the control setup and monitored for 120 days while the metals removal rate was quantified using an atomic absorption spectrometer. A time-dependent and partial sorption of metals was observed with the highest removal rate recorded for cadmium (71.96%), followed by lead (69.23%), vanadium (55.22%), and chromium (41.64%). The uptake and bioaccumulation of metals were reflected in the increased plant biomass (p < 0.05, F = 97.12) and relative growth rate (p < 0.05, F = 1214.35) in duckweed. A coefficient (r2) of 0.951, 0.919, 0.970, and 0.967 was recorded for cadmium, chromium, lead, and vanadium respectively, indicating that the remediation of metals followed the first-order kinetic rate model. This study highlights the efficacy of the lesser duckweed to preferentially remediate metals in an organo-metallic complex medium for potential wastewater treatment in the petrochemical industry.

Appling ecological or nature-based solutions for the treatment of complex wastewater from the petrochemical industry in Africa remains a challenge due to the paucity of evidence-based science to support the implementation that is acceptable to regulators and the industry. Although laboratory and field-based demonstration of phytoremediation studies has shown the potential of macrophytes for the treatment of organic and inorganic pollutants, studies on the application of duckweed for complex organo-metallic wastewater treatment for heavy metals are few. This study demonstrates the efficacy of the lesser duckweed, Lemna aequinoctialis in the sorption of cadmium, chromium, lead, and vanadium from an organo-metallic complex with potential application in the petrochemical industry.

Cytokinin-mediated shoot proliferation and its correlation with phytoremediation effects in Cd-hyperaccumulator ecotype of Sedum alfredii.

The phytohormones cytokinins (CKs) are known to regulate apical/auxiliary meristems, control shoot growth and are associated with nutrient uptake and high biomass production. In this study, different cytokinins were tested on Sedum alfredii (S.alfredii) for shoot proliferation and growth performance as well as their correlation with phytoextraction efficiency. Among the tested cytokinins, Zeatin (ZTN) treatments produced the highest number of shoots (5-6 per explant) with 5 and 10 µM ZTN concentrations which are shown as zeatin (ZTN) > kinetin (KTN) > benzylaminopurine (BA) > thidiazuron (TDZ). Maximum biomass production was produced on these media. The maximum biomass (0.14 g) was found in 10 µM ZTN concentration with a 1-fold difference (mean value: 0.02 g) from CK (0.12 g). However, the lowest biomass (0.11 g) was found with 4 µM TDZ, with a 1-fold difference (mean value: 0.02 g) from CK (0.13 g) which suppressed shoot growth. The leaf area and leaf chlorophyll index were significantly increased in all cytokinins except TDZ, and the relation was ZTN > KTN > BA>CK > TDZ. Cadmium accumulation was significantly higher in treatments containing cytokinins as compared to cytokinin-free media. Zeatin at 10 µM concentration was the most effective for high biomass production and correlated with higher cadmium uptake efficiency. The results suggest that cytokinins particularly ZTN, play a crucial role in enhancing both biomass production and cadmium, uptake efficiency in S. alfredii. Therefore, in large-scale phytoremediation initiatives conducted in field conditions, cytokinins can be utilized as growth regulators to enhance biomass production and cadmium extraction efficiency in S.alfredii.

Multi-pollutant biosorption of organic and inorganic pollutants by brown algae waste from alginate production: batch and fixed-bed investigation.

The reuse of biomass waste has been gaining attention in adsorption processes to remove pollutants of emerging concern from water and wastewater. In this work, the potential of alginate-extracted macro-algae waste to uptake synthetic dyes and metal cations was evaluated in comparison with raw algae. In affinity assays, both materials were able to remove metal cations and cationic dyes up to maximum rates, and no significant removal was observed for an anionic dye in an acidic medium. Competition was observed in multi-component systems of metal cations and dyes. For binary samples containing organic and inorganic contaminants, kinetic modeling evidenced the distinct nature of both types of adsorbates. Pb(II) biosorption was best described as a first-order process, while second-order and Elovich models better fitted methyl blue (MB) uptake data. For equimolar binary samples, the Sips isothermal model fitted the experimental data more satisfactorily at room temperature. Isotherms for 20, 30, 40, and 60 °C exhibited favorable adsorption profiles with spontaneous ΔG values for both raw macro-algae and waste from alginate extraction. Maximum adsorption capacities were competitive with previous reports in the literature for a wide range of biomaterials, pointing to the slightly higher efficiency with algae waste in batch experiments. In elution tests, HNO3 (0.5 M) showed the best recovery rates of metal cations. Continuous biosorption operation revealed the performance of the brown algae waste was considerably more efficient than raw algae with breakthrough biosorption capacities up to 3.96 and 0.97 mmol.g-1 for the removal of Pb(II) and MB, respectively. A total of 3.0 g of algae and algae waste were able to deliver 1.20 and 1.62 L of contaminant-free water, respectively. XPS analyses corroborate previous assays that pointed to the prevalence of physisorption with evidence of complexation, ionic exchange, and hydrogen displacement mechanisms.

Looking at moss through the bioeconomy lens: biomonitoring, bioaccumulation, and bioenergy potential.

The field of bioeconomy has been experiencing a surge in interest in recent years as society increasingly recognizes the potential of utilizing renewable biological resources to create sustainable solutions for economic growth, resource management, and environmental protection. Despite its potential, there is a notable lack of studies exploring the utilization of moss as a viable resource within the bioeconomy framework. Aligned with this objective, this paper conducts a keyword analysis using the VOSviewer application to explore the applicability of mosses as a bioeconomy resource. While biomonitoring using mosses has been studied extensively, this paper shifts its focus to discuss advancements in this area. Moreover, it evaluates the viability of moss utilization for bioenergy production and concisely summarizes their application in microbial fuel cells. The review also highlights challenges pertinent to moss utilization and presents future prospects. The overarching goal of this review paper is to assess the potential and utilization prospects of mosses within the realms of bioaccumulation, air purification, and bioenergy. By offering a comprehensive summary of moss applications, performance, and viability across diverse sectors, this paper endeavors to promote the versatile application of mosses in various contexts. It repositions the discussion on mosses, accentuating their utilization potential prior to exploring conclusions and future prospects.

Mis-regulation of Zn and Mn homeostasis is a key phenotype of Cu stress in Streptococcus pyogenes.

All bacteria possess homeostastic mechanisms that control the availability of micronutrient metals within the cell. Cross-talks between different metal homeostasis pathways within the same bacterial organism have been reported widely. In addition, there have been previous suggestions that some metal uptake transporters can promote adventitious uptake of the wrong metal. This work describes the cross-talk between Cu and the Zn and Mn homeostasis pathways in Group A Streptococcus (GAS). Using a ∆copA mutant strain that lacks the primary Cu efflux pump and thus traps excess Cu in the cytoplasm, we show that growth in the presence of supplemental Cu promotes downregulation of genes that contribute to Zn or Mn uptake. This effect is not associated with changes in cellular Zn or Mn levels. Co-supplementation of the culture medium with Zn or, to a lesser extent, Mn alleviates key Cu stress phenotypes, namely bacterial growth and secretion of the fermentation end-product lactate. However, neither co-supplemental Zn nor Mn influences cellular Cu levels or Cu availability in Cu-stressed cells. In addition, we provide evidence that the Zn or Mn uptake transporters in GAS do not promote Cu uptake. Together, the results from this study strengthen and extend our previous proposal that mis-regulation of Zn and Mn homeostasis is a key phenotype of Cu stress in GAS.

Influence of biochar produced from negative pressure-induced carbonization on transformation of potentially toxic metal(loid)s concerning plant physiological characteristics in industrially contaminated soil.

Soil contamination and its subsequent impact on the food chain is a pressing challenge in the present day. The application of biochar has demonstrated a significant and positive effect on soil health, thereby enhancing plant growth and development. However, the application of biochar (BC) produced from negative pressure-induced carbonization to mitigate metal(loid) contamination is a new strategy that has been studied in current research. Results depicted that the application of biochar derived from the negative pressure carbonization (vacuum-assisted biochar (VBC) has a significant (p ≤ 0.05) positive impact on plant growth and physiological characteristics by influencing immobilization and speciation of metal(loid) in the soil system. Moreover, the interactive effect of VBC on physiological characteristics (photosynthesis, gas exchange, and chlorophyll contents) and antioxidant activities of maize (Zea mays L.) was significantly (p ≤ 0.05) positive by confining the translocation and movement of metal(loid)s to the aerial part of the maize plant. X-ray diffraction (XRD) provided information on the structural and chemical changes induced by the VBC-500 °C explaining metal(loid) adsorption onto mineral surfaces and complexation that can affect their mobility, availability, and toxicity in the contaminated soil. Fourier transform infrared spectroscopy (FTIR) further provided a more detailed understanding of the metal(loid)s and biochar complexation mechanisms influenced by VBC-based functional groups -OH, C-Hn, -COOH, CO, C-O-C, CC, C-O, C-H, OH, and C-C in the binding process. These results suggest that the application of biochar prepared at 500 °C under negative pressure-induced carbonization conditions to the soil is the most efficient way to reduce the uptake and transfer of metal(loid)s by influencing their mobility and availability in the soil-plant system.