Pyrite Biooxidation by Acidophilic Archaea AcidiplasmaSp. MBA-1 Under Varied Conditions

The goal of this research was to study pyrite (FeS2 ) bioleaching by a strain of the genus Acidiplasma under different conditions (temperature, pH) to evaluate the potential role of Acidiplasma representatives in biooxidation of this sulfide mineral. To compare the role of Acidiplasma archaea in pyrite biooxidation with other acidophilic microorganisms, the experiments were also performed with representatives of othergroups of microorganisms predominant in biohydrometallurgical processes.Pure and mixed cultures of moderately thermophilic acidophilic microorganisms, including strains Acidithiobacillus caldus MBC-1, Sulfobacillusthermosulfidooxidans VKMV 1269T and Acidiplasmasp. MBA-1, were used. The experiments were carried out in flasks with 100 mL of mineral nutrient medium supplemented with 0.02% yeast extract and 1 g of pyrite on a rotary shaker for 20 days. Bioleaching was performed at 45, 55, and 60∘С. The results demonstrated that the representatives of the genus Acidiplasmaprovided a comparatively higher rate of pyrite bioleaching at high temperatures (55 and 60∘C) and low pH of the medium (1.0). Thus, according to the results, strains of thegenus Acidiplasma may provide a high rate of pyrite bioleaching at low levels ofpH. Therefore, the results suggest that archaea of the genus Acidiplasma may be promising microorganisms to improve bioleaching processes with an increase in the operational temperature, which is usually maintained at 40–45∘C in industrial-scale reactors. Keywords: biomining, bioleaching, acidophilic microorganisms, sulfide minerals, pyrite

Transient Nutrient Deficiencies in Pea: Consequences on Nutrient Uptake, Remobilization, and Seed Quality

Legume plants, such as peas, are of significant nutritional interest for both humans and animals. However, plant nutrition and thus, seed composition, depends on soil mineral nutrient availability. Understanding the impact of their deprivation on the plant mineral nutrient content, net uptake, and remobilization is of key importance but remains complex as the elements of the plant ionome are linked in intricate networks, one element deprivation impacting uptake and remobilization of other nutrients. To get a better insight into pea mineral nutrition, the transitory deprivations of 13 mineral nutrients were imposed during the vegetative growth phase. Thereafter, plants were grown under optimal mineral conditions until physiological maturity. Plant nutritional status and seed quality impacts caused by the deprivations were characterized using measurement of mineral nutrient concentration and plant biomass allocation. Our results highlight: (i) the preferential allocation of dry weight and elements to shoots at the expense of the roots under non-limiting conditions, and more particularly to the tendrils in comparison to the other shoot organs, (ii) the positive and/or negative impact of one mineral nutrient deprivation on other elements of the ionome, (iii) four different remobilization strategies for eight mineral nutrients, and (iv) possible strategies to improve seed quality via fine control of fertilization during a period of mineral nutrient deficiency.

Regulatory long non-coding RNAs in root growth and development

As sessile organisms, plants have evolved sophisticated mechanisms of gene regulation to cope with changing environments. Among them, long non-coding RNAs (lncRNAs) are a class of RNAs regulating gene expression at both transcriptional and post-transcriptional levels. They are highly responsive to environmental cues or developmental processes and are generally involved in fine-tuning plant responses to these signals. Roots, in addition to anchoring the plant to the soil, allow it to absorb the major part of its mineral nutrients and water. Furthermore, roots directly sense environmental constraints such as mineral nutrient availability and abiotic or biotic stresses and dynamically adapt their growth and architecture. Here, we review the role of lncRNAs in the control of root growth and development. In particular, we highlight their action in fine-tuning primary root growth and the development of root lateral organs, such as lateral roots and symbiotic nodules. Lastly, we report their involvement in plant response to stresses and the regulation of nutrient assimilation and homeostasis, two processes leading to the modification of root architecture. LncRNAs could become interesting targets in plant breeding programs to subtly acclimate crops to coming environmental changes.

Causes of the dieback of littoral stands in an overpopulated water-bird reserve: Role of eutrophication, fish and geese

European fishponds can serve as refuges for water birds if the fish stocks are limited, but the effects of other ecological factors on their ecological stability are rarely considered. The aim of this study is to determine the causes of marked dieback of littoral stands dominated by Typha angustifolia L. in a hypertrophic fishpond that is also a valuable water bird reserve. A field study and two experiments were conducted in order to separate the effects of mineral nutrient availability, redox conditions, fish and water birds. The physico-chemical characteristics of the water and sediments confirmed hypertrophic conditions in the fishpond, but a mesocosm experiment did not indicate it had a negative effect on plant growth. On the other hand, a field enclosure experiment showed that in sparse stands, unfenced parts had a significantly smaller shoot density than fenced parts. This was attributed to grazing by greylag geese (Anser anser L.). In addition, damage to belowground parts of plants were ascribed to large individuals of albeit a few large common carp (Cyprinus carpio L.). This study highlights a conservation dilemma as large numbers of geese destroy littoral stands in fishpond nature reserves, which then become unsuitable nesting sites for other species of water birds.

A Case-Control Study for the Effectiveness of Oral Zinc in the Prevention and Mitigation of COVID-19

Background: The ongoing coronavirus disease-19 (COVID-19) pandemic (caused by an infection with severe acute respiratory syndrome (SARS)-coronavirus (CoV-2) has put a burden on the medical community and society at large. Efforts to reduce the disease burden and mortality over the course of the pandemic have focused on research to rapidly determine age-stratified seroepidemiologic surveys, a centralized research program to fast-track the most promising rapid diagnostics and serologic assays, and the testing of potential anti-viral agents, immunologic therapies, and vaccine candidates. Despite the lack of official recognition for the role of nutrition in the fight against COVID-19 infection, multiple groups proposed zinc supplementation as an adjuvant for the management of participants.Method: In an ambulatory, interventional, prospective, single-blind study, we evaluated the effectiveness of zinc supplementation in the prevention and mitigation of COVID-19 in two similar participant groups. In Clinic A (n = 104) participants were randomized to receive 10 mg, 25 mg, or 50 mg zinc picolinate daily, and Clinic B control participants paired according to their demographics and clinical parameters (n = 96). All participants were compared based on demographics, clinical comorbidities, blood counts, renal functions, vitamin D levels, and their development of symptomatic COVID-19 infection.Results: Symptomatic COVID-19 infection was significantly higher among the control group participants (N = 9, 10.4%) than the treatment participants (N = 2, 1.9%), p = 0.015. The unadjusted odds ratio indicates that symptomatic COVID-19 infection was 5.93 [95% CI: 1.51, 39.26] higher in the control group, p < 0.01. Controlling for co-morbidities, individuals in the control group were 7.38 (95% CI: 1.80, 50.28) times more likely to develop symptomatic COVID-19 infection as compared with individuals in the treatment group (p < 0.01). For every-one unit increase in the number of co-morbidities, the likelihood of developing symptomatic COVID-19 infection increased 1.57 (95% CI: 1.16, 2.19) (p = 0.01).Discussion: The findings from our study suggest that zinc supplementation in all three doses (10, 25, and 50 mg) may be an effective prophylaxis of symptomatic COVID-19 and may mitigate the severity of COVID-19 infection.Conclusion: Zinc is a relatively inexpensive mineral nutrient that is an effective prophylactic agent to prevent and mitigate the potentially deadly symptomatic SARS-CoV-2 infection. As the COVID-19 pandemic continues with a lag in vaccinations in some regions and the continued emergence of dangerously infectious variants of SARS-CoV-2, it is important to replicate our data in other populations and locations and to engage public health and nutrition services on the emergent need to use zinc supplantation or fortification of staple foods in the prevention and mitigation of COVID-19 infection severity.

Dual Inoculation With Arbuscular Mycorrhizal Fungi and Phosphorus Solubilizing Fungi Synergistically Enhances the Mobilization and Plant Uptake of Phosphorus From Meat and Bone Meal

Phosphorus (P) is the second most important mineral nutrient for plant growth and plays a vital role in maintaining global food security. The natural phosphorus reserves [phosphate rock (PR)] are declining at an unprecedented rate, which will threaten the sustainable food supply in near future. Rendered animal byproducts such as meat and bone meal (MBM), could serve as a sustainable alternative to meet crop phosphorus demand. Even though nitrogen (N) from MBM is readily mineralized within a few days, >75% of the P in MBM is present as calcium phosphate that is sparingly available to plants. Thus, application of MBM with the aim of meeting crop N demand could result in buildup of P reserves in soil, which necessitates the need to improve the P mobilization from MBM to achieve higher plant P use efficiency. Here, we tested the potential of two microbial inoculum-arbuscular mycorrhizal fungi (AMF) and P solubilizing fungi (Penicillium bilaiae), in improving the mobilization of P from MBM and the subsequent P uptake by maize (Zea mays). Compared to the non-inoculated MBM control, the application of P. bilaiae increased the P mobilization from MBM by more than two-fold and decreased the content of calcium bound P in the soil by 26%. However, despite this mobilization, P. bilaiae did not increase the tissue content of P in maize. On the other hand, AMF inoculation with MBM increased the plant root, shoot biomass, and plant P uptake as compared to non-inoculated control, but did not decrease the calcium bound P fraction of the soil, indicating there was limited P mobilization. The simultaneous application of both AMF and P. bilaiae in association with MBM resulted in the highest tissue P uptake of maize with a concomitant decrease in the calcium bound P in the soil, indicating the complementary functional traits of AMF and P. bilaiae in plant P nutrition from MBM. Arbuscular mycorrhizal fungi inoculation with MBM also increased the plant photosynthesis rate (27%) and root phosphomonoesterase activity (40%), which signifies the AMF associated regulation of plant physiology. Collectively, our results demonstrate that P mobilization and uptake efficiency from MBM could be improved with the combined use of arbuscular mycorrhizal fungi and P. bilaiae.

Zinc uptake and distribution in ivy (Hedera helix L.) leaves

Detached leaves of ivy (Hedera helix L.) were used as a model for the study of zinc uptake and transport in vascular plants. By the uptake via the surface of fully immersed leaves in 25 % Hoagland nutrient media (HM) spiked with 65ZnCl2 (50 μmol/dm3 ZnCl2), concentration in leaves 4.98 μg Zn/g (dry wt.), i. e. 2.6 μg Zn/dm2 leaf area after 7d exposition were obtained. By the uptake via immersed stalks of not immersed (transpiring) leaves concentrations up to 370 μg Zn/g (dry wt.) were obtained. When Zn enters into detached leaves via the surface of immersed leaf blades, zinc is uniformly distributed in leaf blades and leaf stalks. When zinc enters detached leaves via immersed stalks of non-immersed transpiring leaves, only small part of zinc is transported to leaf blades and the prevailing part remains in leaf stalks. Stalks act as a trap, able to prevent other leaf tissues against inhibitory effects of high Zn concentrations. Mineral nutrient salts in solutions mobilize Zn trapped in leaf stalks and facilitate Zn transport by transpiration stream to leaf blades, what means that Zn in stalks is bound in ion-exchageable forms.

Impact of Foliar Application of Zinc and Magnesium Aminochelate on Bean Physiology and Productivity in Ghana

Foliar application of fertilizers can guarantee nutrient availability to beans, leading to higher yield and seed quality. Different approaches including glycine have been used to improve mineral nutrient status of plants toward safer products and improved human health. However, limited research has been undertaken to understand the response of beans to amino Zn and Mg foliar fertilizer application in Ghana. This study was conducted to investigate the effect of zinc, magnesium, and combined zinc and magnesium foliar fertilizer application on two improved common bean (Phaseolus vulgaris L.) varieties locally referred to as Adoye and Nsroma in the forest (Fumesua) and forest-savannah transition (Akumadan) agro-ecological zones of Ghana during the 2018 and 2019 cropping seasons. The treatments were arranged in split-plot design with the two improved common bean varieties as the main plot, and foliar fertilizer options (zinc, 200 g/ha; magnesium, 224 g/ha; combined zinc and magnesium, 100 g/ha Zn and 112 g/ha Mg) and water spray (control) as the subplot treatments. The zinc and combined zinc and magnesium treatments had similar and significantly ( P ≤ 0.05 ) higher plant height of 37.1 cm and 38.7 cm compared to the control and magnesium treatments. The results also showed that chlorophyll content was approximately 15.6% higher in plants treated with zinc plus magnesium compared to the other treatments. Similarly, stomatal conductance was significantly ( P ≤ 0.05 ) increased by 35.6% with zinc plus magnesium treatment relative to the other treatments. The improved chlorophyll content and stomatal conductance in those treatments resulted in ∼55.3–80.6% increase in crop biomass and seed yield. Crop performance parameters such as plant height, canopy spread, and chlorophyll content were significantly higher ( P ≤ 0.05 ) at Akumadan, resulting in a greater seed yield of 1486.2 kg/ha compared to 1365.3 kg/ha at Fumesua. Combined application of zinc and magnesium appears to be a potential soil improvement strategy for common bean production in tropical soil environment of Ghana.

The Role of Mineral Deficiencies in Insulin Resistance and Obesity

: Minerals are critical for maintaining overall health. These tiny chemical compounds are responsible for enzymatic activation, maintaining healthy teeth and bones, regulating energy metabolism, enhancing immunity and aiding muscle and brain function. However, mineral deficiency in the form of inadequate or under nourished intake affects millions of people throughout the world, with well-documented adverse health consequences of malnutrition. Conversely, mineral deficiency may also be a risk factor for insulin resistance (IR) and obesity. This review focuses on another, more “less discussed” form of malnutrition, namely mineral deficiency and its contribution to metabolic disorders. At the cellular level, minerals maintain not only molecular communication but also trigger several key biochemical pathways. Disturbances in these processes due to mineral insufficiency may gradually lead to metabolic disorders such as insulin resistance, pre-diabetes and central obesity which might lead to renal failure, cardiac arrest, hepatic carcinoma and various neurodegenerative diseases. Here we discuss the burden of disease promoted by mineral deficiencies and the medical, social and economic consequences. Mineral deficiency-mediated IR and obesity have a considerable negative impact on individual well-being and physical consideration and economic productivity. We discuss possible molecular mechanisms of mineral deficiency that may lead to IR and obesity and suggest strategies to counter these metabolic disorders. To protect mankind from mineral nutrient deficiencies, the key is to take a variety of foods in reasonable quantities, such as organic and pasture-raised eggs, low fat dairy, and grass-fed and finished meats, insecticide and pesticide-free vegetables and fruits.