Mn Uptake Research Articles

GmSTOP1-3 Increases Soybean Manganese Accumulation Under Phosphorus Deficiency by Regulating GmMATE2/13 and GmZIP6/GmIREG3.

Mineral nutrient deficiencies and metal ion toxicities coexist on acid soils. Phosphorus (P) deficiency in plants is generally accompanied with significant levels of leaf manganese (Mn) accumulation. However, the molecular regulatory mechanisms underpinning remain unclear. The present study found that P-deficient soybean plants accumulated more Mn compared to P-sufficient ones on acid soils in both field and greenhouse experiments. Meanwhile, both P deficiency and Mn toxicity enhanced the expression of GmSTOP1-3. Over-expressing GmSTOP1-3 enhanced Mn accumulation in transgenic soybean hairy roots, but RNA-interference did not show obvious differences. Moreover, transgenic soybeans with GmSTOP1-3-overexpression showed enhanced root citrate exudation and augmented Mn accumulation. RNA-sequence identified four downstream genes of GmSTOP1-3, including multidrug and toxic compound extrusion (GmMATE2/13) and metal transporter genes (GmZIP6/GmIREG3), which encode plasma membrane proteins. GmSTOP1-3 activated the transcription of these four genes by directly binding to their promoter regions. In addition, both GmZIP6 and GmIREG3 functioned in Mn uptake as manifested by the higher Mn concentration and decreased growth of soybean hairy roots with their overexpression. Taken together, it is suggested that upregulation of GmSTOP1-3 by low P stress on acid soils activates transcripts of GmMATE2/13 and GmZIP6/GmIREG3, which consequently result in enhanced Mn accumulation in soybean.

Neuronal SLC39A8 deficiency impairs cerebellar development by altering manganese homeostasis.

Solute carrier family 39, member 8 (SLC39A8), is a transmembrane transporter that mediates the cellular uptake of zinc, iron, and manganese (Mn). Human genetic studies document the involvement of SLC39A8 in Mn homeostasis, brain development, and function. However, the role and pathophysiological mechanisms of SLC39A8 in the central nervous system remain elusive. We generated Slc39a8 neuron-specific knockout (Slc39a8-NSKO) mice to study SLC39A8 function in neurons. The Slc39a8-NSKO mice displayed markedly decreased Mn levels in the whole brain and brain regions, especially the cerebellum. Radiotracer studies using 54Mn revealed that Slc39a8-NSKO mice had impaired brain uptake of Mn. Slc39a8-NSKO cerebellums exhibited morphological defects and abnormal dendritic arborization of Purkinje cells. Reduced neurogenesis and increased apoptotic cell death occurred in the cerebellar external granular layer of Slc39a8-NSKO mice. Brain Mn deficiency in Slc39a8-NSKO mice was associated with motor dysfunction. Unbiased RNA-Seq analysis revealed downregulation of key pathways relevant to neurodevelopment and synaptic plasticity, including cAMP signaling pathway genes. We further demonstrated that Slc39a8 was required for the optimal transcriptional response to the cAMP-mediated signaling pathway. In summary, our study highlighted the essential roles of SLC39A8 in brain Mn uptake and cerebellum development and functions.

Assessment of manganese accumulation in dryland wheat grains via plastic film mulching: Implications for human health risk in multi-site studies

Crop manganese (Mn) accumulation and the associated human health risks stemming from excessive intake of high Mn crop foods have attracted attention. However, there is limited information available concerning the impact of plastic film mulching (PFM) on Mn concentration in cereal grains and the health risks associated with Mn intake by the human body. Field experiments were conducted from 2014 to 2016 at seven sites in the drylands of a typical wheat-growing region in China to assess the effect of PFM on grain Mn concentration, Mn accumulation and distribution in winter wheat plants, and the potential risk of Mn intake and optimal grain intake for human health. The multi-site study results revealed that grain Mn concentration and bioavailability were significantly higher under PFM compared to no mulching. Similarly, PFM was found to enhance aboveground Mn accumulation at the anthesis stage by 17.5 %, Mn harvest index by 3.9 %, grain Mn accumulation by 28.9 %, and available Mn concentration in the soil by 10.9 %. The increased uptake and accumulation of Mn in wheat plants, leading to elevated grain Mn concentration, were primarily attributed to the improved availability of Mn and moisture in the soil under PFM treatment. Furthermore, a health risk assessment indicated that long-term consumption of whole wheat grains from PFM treatment could potentially pose a non-carcinogenic risk of Mn for children and adolescents residing in rural areas. Therefore, this study established upper limits for daily consumption of whole wheat grains based on the specific needs of local residents. The findings of this research underscore the potential health risks associated with consuming grain crops grown in PFM crop production systems.

Nutrient Use Efficiency and Cucumber Productivity as a Function of the Nitrogen Fertilization Rate and the Wood Fiber Content in Growing Media.

A peat substrate is made from peat from drained peatlands, which is a limited resource. A realistic estimate is that 50% of the world's wetlands have been lost. Peat is used in horticulture, especially for the cultivation of vegetables in greenhouses. The consequences of peatland exploitation are an increase in the greenhouse effect and a decrease in carbon stocks. Wood fiber can be used as an alternative to peat. The chemical properties of growing media interact and change continuously due to the small volume of growing media, which is limited by the growing container. This study aims to gain new knowledge on the impact of nutrient changes in the microbial degradation of carbon compounds in wood fiber and mixtures with a peat substrate on the content and uptake of nutrients required by plants. The cucumber (Cucumis sativus L.) variety 'Dirigent H' developed in the Netherlands was cultivated in growing media of a peat substrate and wood fiber: (1) peat substrate (PS); (2) wood fiber (WF); (3) wood fiber and peat substrate 50/50 v/v (WF/PS 50/50); (4) wood fiber and peat substrate 25/75 v/v (WF/PS 25/75). The rates of fertilization were the following: (1) conventional fertilization (CF); (2) 13 g N per plant (N13); (3) 23 g N per plant (N23); (4) 30 g N per plant (N30). The experiment was carried out with three replications. As the amount of wood fiber increased, the humidity and pH of the growing media increased. The fertilization of the cucumbers with different quantities of nitrogen influenced the nutrient uptake. The plants grown in the 50/50 and 25/75 growing media had the best Cu uptake when fertilized with N23. When the plants grown in the wood fiber media and the 50/50 media were fertilized with N13, N23, and N30, the Mn content in the growing media at the end of the growing season was significantly lower than the Mn content in the media with conventional fertilization. Thus, nitrogen improved the uptake of Mn by the plants grown not only in the wood fiber, but also in the combinations with a peat substrate. Growing plants in wood fiber and fertilizing them with N13 can result in the optimum uptake of micronutrients. The number and biomass of cucumber fruits per plant were influenced by the amount of wood fiber in the growing media and the application of nitrogen fertilizer. The highest number of fruits and biomass of fruits per plant obtained were significantly higher when the cucumbers were grown in WF/PS 50/50 growing media with additional N13 fertilization.

Micronutrients concentration and content in corn as affected by nitrogen, phosphorus, and potassium fertilization

AbstractThe interaction between nitrogen (N), phosphorus (P), and potassium (K) fertilizers significantly impacts the uptake of micronutrients in corn, influencing their availability in soil and uptake by plants. Understanding the interaction of macro‐ and micronutrients is a prerequisite to targeting nutrient balance in crop production. Therefore, a 2‐year field experiment was conducted to determine the effect of NPK fertilization on micronutrient uptake of rain‐fed corn (Zea mays L.). A randomized complete block design was employed with 12 treatments replicated three times. Different combinations of N, P, and K fertilizer rates were investigated for micronutrient concentration and uptake in rain‐fed corn. Findings revealed the order of nutrient accumulation in corn plants: iron (Fe) > manganese (Mn) > zinc (Zn) > copper (Cu). Nitrogen application influenced nutrient concentrations and uptake. Increasing N rates increased micronutrient concentrations in corn grain, except for Cu. Interestingly, Cu content in grains exhibited no correlation with nutrient supply, biomass, or other concentrations. As the N application rate increased, micronutrient content increased at early growth stage and physiological maturity. Phosphorus application showed negligible impact on grain micronutrient concentration and uptake. However, K application notably increased Mn, Fe, and Cu uptake in grains. This study underscores the need to consider not only grain yield but also nutritional quality when determining optimal NPK rates in rain‐fed corn cultivation.

Residual Effect of Water Soluble Fertilizers on Productivity and Nutrients Uptake of Cowpea in Aerobic Rice-cowpea Cropping Sequence under Fertigaton

A field experiment was under taken at University of Agricultural Sciences, GKVK, Bengaluru, Karnataka state, India to study the residual effect of fertigation of water soluble fertilizers on productivity and nutrients uptake of cowpea under aerobic rice-cowpea cropping sequence during Kharif 2015-16 and 2016-17 with 16 treatments replicated thrice in randomized block design. Significantly higher plant height (58.47 cm), number of branches plant-1 (11.71) and total dry matter accumulation plant-1 (70.60 g) were recorded in fertigation with 100% RDF through water soluble fertilizer at 8 DI. Likely, similar treatment 100% RDF through water soluble fertilizer at 8 DI was recorded significantly higher number of pods plant-1 (16.58), pod length (16.67 cm), seeds per pod (16.10), test weight (11.93 g), seed yield (12.94 q ha-1) and haulm yield (26.17 q ha-1). While higher total uptake of N, P and K by cowpea (68.94, 14.67 and 61.39 kg N, P and K ha-1, respectively) was recorded in 100% RDF through water soluble fertilizers at 4 DI (T5) than all other treatments. 100% RDF through WSF at 8 DI (T8) was recorded notably higher total Ca, Mg and S uptake by cowpea (50.71, 24.71 and 12.09 kg Ca, Mg and S ha-1, respectively). Significantly higher uptake of total Fe, Zn and Cu by cowpea crop (680.23, 91.30 and 38.27 g ha-1, respectively) was recorded with 100% RDF through water soluble fertilizers at 8 DI (T8). Total uptake of Mn was recorded higher by cowpea was observed (181.67 g ha-1) in 100% STCR dose through water soluble fertilizers at 4 DI (T11).

Expression of Manganese Transporters ZIP8, ZIP14, and ZnT10 in Brain Barrier Tissues.

Manganese (Mn) is an essential trace mineral for brain function, but excessive accumulation can cause irreversible nervous system damage, highlighting the need for proper Mn balance. ZIP14, ZnT10, and ZIP8 are key transporters involved in maintaining Mn homeostasis, particularly in the absorption and excretion of Mn in the intestine and liver. However, their roles in the brain are less understood. The blood-cerebrospinal fluid barrier and the blood-brain barrier, formed by the choroid plexus and brain blood vessels, respectively, are critical for brain protection and brain metal homeostasis. This study identified ZIP14 on the choroid plexus epithelium, and ZIP8 and ZnT10 in brain microvascular tissue. We show that despite significant Mn accumulation in the CSF of Znt10 knockout mice, ZIP14 expression levels in the blood-cerebrospinal fluid barrier remain unchanged, indicating that ZIP14 does not have a compensatory mechanism for regulating Mn uptake in the brain in vivo. Additionally, Mn still enters the CSF without ZIP14 when systemic levels rise. This indicates that alternative transport mechanisms or compensatory pathways ensure Mn balance in the CSF, shedding light on potential strategies for managing Mn-related disorders.

Hormetic responses to cadmium exposure in wheat seedlings: insights into morphological, physiological, and biochemical adaptations.

Cadmium is commonly recognized as toxic to plant growth, low-level Cd has promoting effects on growth performance, which is so-called hormesis. Although Cd toxicity in wheat has been widely investigated, knowledge of growth response to a broad range of Cd concentrations, especially extremely low concentrations, is still unknown. In this study, the morphological, physiological, and biochemical performance of wheat seedlings to a wide range of Cd concentrations (0-100 µΜ) were explored. Low Cd treatment (0.1-0.5µM) improved wheat biomass and root development by enhancing the photosynthetic system and antioxidant system ability. Photosynthetic rate (Pn) was improved by 5.72% under lower Cd treatment (1 µΜ), but inhibited by 6.05-49.85% from 5 to 100 µΜ. Excessive Cd accumulation induced oxidative injury manifesting higher MDA content, resulting in lower photosynthetic efficiency, stunted growth, and reduction of biomass. Further, the contents of ascorbate, glutathione, non-protein thiols, and phytochelatins were improved under 5-100 µΜ Cd treatment. The ascorbate peroxidase activity in the leaf showed a hormetic dose-response characteristic. Correlation analysis and partial least squares (PLS) results indicated that antioxidant enzymes and metabolites were closely correlated with Cd tolerance and accumulation. The results of the element network, correlation analysis, and PLS showed a crucial role for exogenous Cd levels in K, Fe, Cu, and Mn uptake and accumulation. These results provided a deeper understanding of the hormetic effect of Cd in wheat, which would be beneficial for improving the quality of hazard and risk assessments.

Manganese enhances cadmium tolerance in barley through mediating chloroplast integrity, antioxidant system, and HvNRAMP expression

Cadmium (Cd) is a toxic heavy metal that poses risks to crop production and food safety worldwide. This study evaluated whether manganese (Mn) addition could mitigate Cd toxicity and reduce Cd accumulation in barley seedlings. Hydroponically grown seedlings of Cd-tolerant (WSBZ) and Cd-sensitive (Dong17) barley cultivars were treated with 0.1 μM and 1 μM Cd as well as 0.2 mM Mn alone and in a combination with 0.1 or 1.0 μM Cd for 21 days. Cd exposure caused the dramatic alteration of growth and physiological parameters by disrupting chloroplast, and increased Cd accumulation in both genotypes. However, Mn addition markedly alleviated the negative impacts of all examined parameters caused by Cd stress. Cd addition enhanced expression of anti-oxidative enzyme related genes, including HvSOD, HvCAT, HvAPX, HvPOD in the two barley genotypes exposed to Cd stress. The expression analysis showed nearly all HvNRAMPs genes are dramatically up regulated by both Mn and Cd, with WSBZ having higher expression than Dong 17. Notably, HvNRAMP1 showed the highest expression due to Mn addition, highlighting its crucial role in Mn uptake and transportation in barley. Moreover, Cd stress and Mn addition increased and suppressed the expression of HvYSL5, HvHMA2 and HvHMA3, respectively. Conversely, the expression of HvYSL2, HvIRT1 and HvMTP8 was upregulated by both Mn and Cd treatments, with a further increase observed in the combined Cd and Mn treatments. It may be concluded that sufficient Mn supply is quite important for reducing Cd uptake and accumulation in plants.

Effects of cadmium stress on the growth, physiology, mineral uptake, cadmium accumulation and fruit quality of 'Sharpblue' blueberry

Cadmium (Cd) contamination is becoming a widespread environmental problem, and Cd toxicity risk is increasing in blueberries, typical acidophilous plants. However, studies on the physiological mechanisms of Cd toxicity affecting the growth of blueberry plants and fruits remain limited. Herein, a pot experiment involving four treatments, CK (0 mg·kg−1), Cd1 (2.5 mg·kg−1), Cd2 (15 mg·kg−1) and Cd3 (50 mg·kg−1), was conducted to investigate the effects of Cd stress on the growth, fruit quality, physiological characteristics, mineral composition and Cd uptake of 'Sharpblue' blueberry cuttings, and relationships between physicochemical indices and phenotypic data under Cd stress were analyzed via principal component analysis and Mantel's test. Compared with CK, Cd treatment led to chlorosis (decrease in SPAD and N content) in 'Sharpblue' leaves and inhibited increases in plant height, basal stem, crown width and biomass (dry weight), with the most significant changes in the 50 mg·kg−1 Cd treatment. The size and thickness of the upper epidermal cells, as well as the thickness of the palisade mesophyll and spongy tissues of 'Sharpblue' were significantly reduced at Cd > 15 mg·kg−1, while the density of stomata was significantly increased. Moreover, Cd stress reduced the yield (decrease in size and single-fruit weight) and quality (decrease in anthocyanin, flavonoid and total phenol content and increase in titratable acid content) of 'Sharpblue' fruits, and Cd content in fruit exceeded the Chinese food safety threshold of 0.05 mg·kg−1 when Cd > 15 mg·kg−1. The Cd enrichment capacity of different organs of 'Sharpblue' plants was in the following order: root > shoot > leaf > fruit, and the 50 mg·kg−1 Cd treatment significantly inhibited the uptake of Fe, Mn, Cu, and Zn. Additionally, 'Sharpblue' plants responded to H2O2 and malondialdehyde accumulation in different organs under Cd stress by regulating levels of osmoregulatory substances (soluble protein (SP), soluble sugar, and proline) and altering the activities of catalase, superoxide dismutase, ascorbic acid, and glutathione in the antioxidant system. Finally, correlation analysis revealed that Mg, Fe, Mn, Cu, Cd, H2O2, SP, SPAD, N, anthocyanin, titratable acid, flavonoids, and total phenols were strongly correlated with 'Sharpblue' growth, leaf and fruit phenotype under Cd stress. These findings provide theoretical information for soil safety management and the breeding of Cd-tolerant cultivars during blueberry cultivation, as well as for the study of Cd stress response mechanisms in acidophilous plants.

The Emergence of the Slc11 Clade MCbgut: A Parsimonious Hypothesis for the Dawn of Lactobacillales in the Gut of Early Vertebrates

The Lactobacillales (LB) stand apart among bacterial orders, using manganese (Mn) instead of iron to support their growth and swiftly ferment complex foods while acidifying their environment. The present work investigates whether a shift in the use of Mn could mark the origin of LB. Transmembrane carriers of the ubiquitous Slc11 family play key roles in LB physiology by catalyzing proton-dependent Mn import. In prior studies, the Slc11 clade found in LB (MntH Cb, MCb) showed both remarkable structural plasticity and highly efficient Mn uptake, and another Slc11 clade, MCg1, demonstrated divergent evolution coinciding with emergence of bacterial genera (e.g., Bordetella, Achromobacter). Herein, the Slc11 clade MCb is subdivided in sister groups: MCbie and MCbgut. MCbie derives directly from the Slc11 clade MCa, pointing an intermediate stage in the evolution of MCbgut. MCbie predominates in marine Bacillaceae, is more conserved than MCbgut, lacks the structural plasticity that typify MCbgut carriers, and responds differently to identical mutagenesis. Exchanging MCbie/MCbgut amino acid residues at sites that distinguish these clades showed conformation-dependent effects with both MCbie and MCbgut templates, and the 3D location of the targeted sites in the carrier structure together suggests that the mechanism to open the inner gate, and release Mn into the cytoplasm, differs between MCbie and MCbgut. Building on the established phylogeny for Enterococcus revealed that a pair of genes encoding MCbgut was present in the common ancestor of LB, as MCbgu1 and MCbgu2 templates exhibited distinct structural dynamics properties. These data are discussed when examining whether MCbgut+ LB could emerge in the upper gut of early vertebrates (ca. 540 mya), through genome contraction and evolution toward Mn-centrism, as they specialized as gastric aids favoring stomach establishment in jawed vertebrates through bi-directional communication with host nervous, endocrine and immune systems.

Phosphorus-induced restructuring of the ascorbate-glutathione cycle and lignin biosynthesis alleviates manganese toxicity in peach roots.

Manganese (Mn) is indispensable for plant growth, but its excessive uptake in acidic soils leads to toxicity, hampering food safety. Phosphorus (P) application is known to mitigate Mn toxicity, yet the underlying molecular mechanism remains elusive. Here, we conducted physiological and transcriptomic analyses of peach roots response to P supply under Mn toxicity. Manganese treatment disrupted root architecture and caused ultrastructural damage due to oxidative injury. Notably, P application ameliorated the detrimental effects and improved the damaged roots by preventing the shrinkage of cortical cells, epidermis and endodermis, as well as reducing the accumulation of reactive oxygen species (ROS). Transcriptomic analysis revealed the differentially expressed genes enriched in phenylpropanoid biosynthesis, cysteine, methionine and glutathione metabolism under Mn and P treatments. Phosphorus application upregulated the transcripts and activities of core enzymes crucial for lignin biosynthesis, enhancing cell wall integrity. Furthermore, P treatment activated ascorbate-glutathione cycle, augmenting ROS detoxification. Additionally, under Mn toxicity, P application downregulated Mn uptake transporter while enhancing vacuolar sequestration transporter transcripts, reducing Mn uptake and facilitating vacuolar storage. Collectively, P application prevents Mn accumulation in roots by modulating Mn transporters, bolstering lignin biosynthesis and attenuating oxidative stress, thereby improving root growth under Mn toxicity. Our findings provide novel insights into the mechanism of P-mediated alleviation of Mn stress and strategies for managing metal toxicity in peach orchards.

Dynamics of Fe, Mn, and potentially harmful elements under reducing conditions in iron ore tailings after dam collapse in the Doce River basin-Brazil: flooded and non-flooded rice cultivations.

Potentially harmful element (PHE) bioavailability is important to environmental contamination and must be checked under several soil conditions. This study aimed to assess Fe, Mn, and PHE uptake by rice (Oryza sativa) grown on flooded and non-flooded Fe tailings collected from the Doce River basin after its collapse in Brazil. After 65days of sowing, shoots and roots were harvested to determine PHE concentrations. The mean concentrations of Mn in shoots and Fe in the roots of rice grown on the flooded tailings were 2140mgkg-1 and 15,219mgkg-1, respectively. Mn was extensively translocated from roots to shoots (translocation factor (TF) = 2). Conversely, Fe accumulated in roots (TF = 0.015) and caused morphological damage to this rice organ. The application of macro and micronutrients lessened Fe toxicity in the roots of rice cultivated on the flooded tailings. The flooding of tailings influenced more Fe accumulation than Mn accumulation by rice plants. The PHE Ag, As, Cd, Ni, Hg, Pb, and Sb exhibited low total concentrations (maximum of 9mgkg-1 for Ni and a minimum of 0.2mgkg-1 for Cd, Hg, and Sb), and it was not observed an increase in their availability under tailings flooding conditions.

Effect of Different Zinc Sources and Application Methods on Content and Uptake of Micronutrients of Basmati Rice

Zinc (Zn) is an essential trace element for plants, animals and human’s health. Zn deficiency is widely spread in paddy soils of India and has negative impact on national rice production. Field experiment on rice crop was conducted in sandy loam soil at crop research center Chirodi of SVBP University of Agriculture and Technology, Meerut., during Kharif season of 2011 and 2012 toevaluate the “Effect of different sources and application methods of zinc on content and uptake of micronutrients in basmati rice crop in sandy loam soil. The experiment was laid out in randomized block design with three replications. The experiment comprised of twelve treatments viz.; T1 (control), T2 (recommended NPK @120:60:60 kg ha-1) T3 (5 kg Zn through ZnSO4.7H2O+RDF), T4(5 kg Zn through mono ZnSO4.7H2O),T5 (0.1% Zn spray through ZnSO4.7H2O+RDF ),T6 (0.1% Zn spray through ZnSO4.7H2O + RDF),T7 (0.012% Zn spray through chelated Zn at tillering + RDF),T8 (0.05% Zn spray through ZnSO4.7H2O at tillering +0.05% at panicle initiation+ RDF), T9 (0.05% Zn spray through mono ZnSO4.7H2O at tillering + 0.05% at panicle initiation +RDF),T10 (0.006% Zn spray through chelated Zn at tillering + 0.006% at panicle initiation+ RDF ), T11 (micronutrient mixture@ 25kg ha-1 + RDF), T12 (vermicompost @ 3tha-1+ RDF).The experimental soil was low in organic carbon and available nitrogen and medium in phosphorus and higher in potassium with slightly alkaline in pH. The status of DTPA extractable Zn 1.23 mg Kg-1,Fe 14.85 mg Kg-1 Cu 2.43 mg Kg-1 Mn 10.91 mg Kg-1 in the surface soil. Nutrient assimilation at different stages by the rice crop varied significantly due to application of different treatments in the study. Maximum zinc content 85.78 and 93.57 ppm and uptake 288.60 and 341.85 g/ha at 30 DAT during 2011 and 2012 found in T12 which was significantly higher than the rest of the treatments while minimum zinc content recorded in T1 was significantly lower than the rest of the treatments during both the years. Similar trends were also recorded at 60 DAT, grain and straw growth stages of rice plant. The zinc content of plant sample in T11 and T3 was also higher and statistically at par to the level of zinc content recorded in T12. The Cu, Fe, and Mn content and uptake at different growth stages of rice plant sample in T11 and T3 was also higher and like the level in T12. Among the method of Zn application, soil application resulted in higher biomass, micronutrient content and uptake in the grain and straw. Foliar application caused greater effect on zinc content and uptake and as well as content and uptake of Cu, Fe and Mn in rice plant at different growth stages during both the years. Among the sources of Zinc, ZnSO4.7H2O proved to be the most efficient source of Zn for rice production.

Nutritional Value of Coloured Flesh Potato Tubers in Terms of Their Micronutrient Content

The aim of this study was to compare Fe, Zn, Mn, Al and Li contents in table potato tubers, obtained from seven potato cultivars with different flesh colour, and one cultivar characterised by light-coloured flesh. The study material consisted of potato tubers produced in a one-factor field experiment carried out at the Agricultural Experimental Station in Zawady belonging to the University of Siedlce, Poland (52°03′ N, 22°33′ E) in 2021–2023. The following cultivars were tested: Eurostar (light yellow flesh), Rote Emmalie and Herbie 26 (red flesh), Provita, Salad Blue, Blaue Annelise, Vitelotte Noire and Bora Valley (purple and blue flesh). The study showed that the genetic characteristics of the cultivars determined the nutrient content and uptake with tuber yield. Of the tested minerals which are important for human nutrition (Fe, Zn, Mn), red and purple cultivars accumulated more Fe than the light yellow-fleshed Eurostar. Zn content was the highest in red-fleshed cultivars compared with light and purple-fleshed cultivars. Mn content was the highest in the tubers of the light yellow-fleshed Eurostar and lowest in red Rote Emmalie. Fe, Zn, Mn and Al contents and uptake with tuber yield were influenced by weather conditions during the growing season.

The role of ruminant urine and faeces in the recycling of nutrients by forages

This study addresses the effect of using animal excreta on the nutritional content of forages, focusing on macro- and micro-element concentrations (nitrogen; N, phosphorus; P, sulphur; S, copper; Cu, zinc; Zn, manganese; Mn, selenium; Se) from animal feed to excreta, soil, and plants. Data were collected from pot and field trials using separate applications of sheep or cattle urine and faeces. Key findings indicate that soil organic carbon (SOC) and the type of excreta significantly influences nutrient uptake by forages, with varied responses among the seven elements defined above. Although urine contributes fewer micronutrients compared to faeces (as applied at a natural volume/mass basis, respectively), it notably improves forage yield and micronutrient accumulation, thus potentially delivering positive consequences at the farm level regarding economic performance and soil fertility when swards upon clayey soil types receive said urine in temperate agro-climatic regions (i.e., South West England in the current context). In contrast, faeces application in isolation hinders Se and Mn uptake, once again potentially delivering unintended consequences such as micronutrient deficiencies in areas of high faeces deposition. As it is unlikely that (b)ovine grazing fields will receive either urine or faeces in isolation, we also explored combined applications of both excreta types which demonstrates synergistic effects on N, Cu, and Zn uptake, with either synergistic or dilution effects being observed for P and S, depending largely on SOC levels. Additionally, interactions between excreta types can result in dilution or antagonistic effects on Mn and Se uptake. Notably, high SOC combined with faeces reduces Mn and Se in forages, raising concerns for grazed ruminant systems under certain biotic situations, e.g., due to insufficient soil Se levels typically observed in UK pastures for livestock growth. These findings underscore the importance of considering SOC and excreta nutritional composition when designing forage management to optimize nutrient uptake. It should be noted that these findings have potential ramifications for broader studies of sustainable agriculture through system-scale analyses, as the granularity of results reported herein elucidate gaps in knowledge which could affect, both positively and negatively, the interpretation of model-based environmental impact assessments of cattle and sheep production (e.g., in the case of increased yields [beneficial] or the requirement of additional synthetic supplementation [detrimental]).

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.

Effect of Mn on Cd2+ uptake by protoplasts of the Cd/Mn hyperaccumulator Celosia argentea Linn. differs by treatment method

The effect mechanism of Mn on Cd uptake by Celosia argentea was investigated via a series of hydroponics experiments. The results showed that different manganese treatments had different effects on Cd uptake by C. argentea. Mn pretreatment increased Cd uptake by root protoplasts at Cd concentrations (4 and 6 μM). Protoplasts reached peak Cd uptake rate at 6 μM Cd and 25 °C, with 67.71 ± 0.13 μM h−1 mL−1 in the control, and 77.99 ± 0.49 μM h−1 mL−1 in the 50 μM Mn pretreatment group. However, simultaneous treatment with Cd and Mn reduced the Cd2+ uptake by root protoplasts. This discrepancy may be attributed to the fact that cadmium and manganese share some transporters in root cells. The transcriptome analysis in roots revealed that ten genes (including ABCC, ABCA, ABCG, ABCB, ABC1, BZIP19, and ZIP5) were significantly upregulated in response to Mn stress (p < 0.05). These genes regulate the expression of transporters belonging to the ABC, and ZIP families, which may be involved in Cd uptake by root cells of C. argentea. Mn pretreatment upregulates the expression of Mn/Cd transporters, enhancing Cd uptake by root protoplasts. For the simultaneous treatment of Cd and Mn, inhibition of Cd uptake was due to the competition of the same transporters. These findings provide helpful insights for understanding the mechanism of Mn and Cd uptake in hyperaccumulators and give implications to improve the phytoremediation of Cd-contaminated soil by C. argentea.

Reduced Mn uptake of pleiotropic ZIP8 SNP is caused by its loss of Mn-responsive accumulation on the cell-surface.

Zrt/Irt-like protein 8 (ZIP8), which is a Zn transporter, plays a pivotal role as a Mn transporter. Recent studies have shown that a ZIP8 SNP (rs13107325 C→T, A391T) is associated with multiple diseases, likely by causing systemic Mn deficiency. However, the underlying molecular mechanisms remain unclear. We attempted to address this issue in cell-based experiments using Madin-Darby canine kidney cells stably expressing ZIP8 WT or the A391T SNP mutant under the control of the Tet-regulatable promoter. We showed that the A391T mutant lost the property of Mn-responsive accumulation on the cell surface, which was observed in WT ZIP8. We also showed that the loss of Mn-responsive accumulation of A391T mutant was associated with its reduced Mn uptake, compared with WT ZIP8, in the Mn uptake assay using the radioisotope 54Mn. Our results potentially explain how the ZIP8 A391T substitution is associated with disease pathogenesis caused by Mn deficiency.

Synthesis and Characterization of Zinc Oxide Nanoparticle Anchored Carbon as Hybrid Adsorbent Materials for Effective Heavy Metals Uptake from Wastewater

Hybrid material-derived adsorbents have shown a great applicable efficiency in various fields, including industrial uses and environmental remediation. Herein, zinc oxide nanoparticle modified with carbon (ZnO-C) was fabricated and utilized for wastewater treatment through the adsorption of Zn(II), Cd(II), Co(II), and Mn(II). The surface and structural characteristics were examined using TEM, SEM, XRD, FTIR spectroscopy, EDS, and the BET surface area. Kinetics and equilibrium investigations were applied to optimize the adsorptive removal of Zn(II), Cd(II), Co(II), and Mn(II) onto ZnO-C. The results indicated that the formation of ZnO-C in crystalline sphere-like granules with a nano-size between 16 and 68 nm together with carbon matrix. In addition, the spherical granules of zinc oxide were gathered to form clusters. FTIR spectroscopy indicated that the ZnO-C surface was rich with OH groups and ZnO. The adsorption capacity 215, 213, 206, and 231 mg/g for Zn(II), Cd(II), Co(II), and Mn(II), respectively, at the optimal conditions pH between 5 and 6, a contact time of 180 min, and an adsorbent dose of 0.1 g/L. The adsorptive removal data modeling for the uptake of Zn(II), Cd(II), Co(II), and Mn(II) onto ZnO-C showed agreement with the assumption of the pseudo-second-order kinetic model and the Freundlich isotherm, suggesting a fast adsorption rate and a multilayered mechanism. The achieved adsorption capacity using the prepared ZnO-C was more effective compared to ZnO, carbon, Fe3O4, and Fe3O4-C. Real wastewater samples were applied, including valley water, industrial wastewater, and rain wastewater, and evaluated for the applicable uptake of Zn(II), Cd(II), Co(II), and Mn(II) using ZnO-C and Fe3O4-C with effective removal efficiency.