Extreme Acid Research Articles

Protamine-Mediated Tangles Produce Extreme Deoxyribonucleic Acid Compaction.

In sperm cells, protamine replaces histones to compact DNA 10-20 times more than in somatic cells. To characterize the extreme compaction, we employed confocal microscopy and optical tweezers to determine the conformations and stability of protamine-bound λ-DNA. Confocal images show increasing compaction of λ-DNA at increasing protamine concentration. In the presence of protamine, single λ-DNA molecules form tangles that withstand forces strong enough (∼55 pN) for strand separation and shorten the contour length by up to 40% even at high forces, as well as bends and loops that rupture at 10-40 pN forces. Strand separation nucleates tangles, implicating protamine interactions with DNA bases. Molecular dynamics simulations show that Arg sidechains of protamine each form hydrogen bonds with multiple bases, frequently in the form of a wedge between the two strands of DNA. Protamine may participate in both local and higher-order chromatin organization, leading to extreme compaction and global transcription silencing.

Deciphering the enigmatic PilY1 of Acidithiobacillus thiooxidans: An in silico analysis

Thirty years since the first report on the PilY1 protein in bacteria, only the C-terminal domain has been crystallized; there is no study in which the N-terminal domain, let alone the complete protein, has been crystallized. In our laboratory, we are interested in characterizing the Type IV Pili (T4P) of Acidithiobacillus thiooxidans. We performed an in silico characterization of PilY1 and other pilins of the T4P of this acidophilic bacterium. In silico characterization is crucial for understanding how proteins adapt and function under extreme conditions. By analyzing the primary and secondary structures of proteins through computational methods, researchers can gain valuable insights into protein stability, key structural features, and unique amino acid compositions that contribute to resilience in harsh environments. Here, it is presented a description of the particularities of At. thiooxidans PilY1 through predictor software and homology data. Our results suggest that PilY1 from At. thiooxidans may have the same role as has been described for other PilY1 associated with T4P in neutrophilic bacteria; also, its C-terminal interacts (interface interaction) with the minor pilins PilX, PilW and PilV. The N-terminal region comprises domains such as the vWA and the MIDAS, involved in signaling, ligand-binding, and protein-protein interaction. In fact, the vWA domain has intrinsically disordered regions that enable it to maintain its structure over a wide pH range, not only at extreme acidity to which At. thiooxidans is adapted. The results obtained helped us design the correct methodology for its heterologous expression. This allowed us partially experimentally characterize it by obtaining the N-terminal domain recombinantly and evaluating its acid stability through fluorescence spectroscopy. The data suggest that it remains stable across pH changes. This work thus provides guidance for the characterization of extracellular proteins from extremophilic organisms.

Interaction between acid-tolerant alga Graesiella sp. MA1 and schwertmannite under long-term acidic condition

Schwertmannite (Sch), a typical Fe(III)-oxyhydroxysulphate mineral, is the precipitation reservoir of toxic elements in acid mine drainage (AMD). Acid-tolerant microbes in AMD can participate in the microbe-mediated transformation of Sch, while Sch affects the physiological characteristics of these acid-tolerant microbes. Based on our discovery of algae and Sch enrichment in a contaminated acid mine pit lake, we predicted the interaction between algae and Sch when incubated together. The acid-tolerant alga Graesiella sp. MA1 was isolated from the pit-lake surface water of an acidic mine and incubated with different contents of Sch. Sch was detected as the main product at the end of 81 d; however, there was a weak transformation. The presence of dissolved Fe(II) could be largely attributed to the photoreduction dissolution of Sch, which was promoted by Graesiella sp. MA1. The adaptation and growth phases of Graesiella sp. MA1 differed under Sch stress. The photosynthetic and metabolic activities increased and decreased at the adaptation and growth phases, respectively. The MDA contents and antioxidant activity of SOD, APX, and GSH in algal cells gradually enhanced as the Sch treatment content increased, indicating a defense strategy of Graesiella sp. MA1. Metabolomic analysis revealed that Sch affected the expression of significant differential metabolites in Graesiella sp. MA1. Organic carboxylic acid substances were essentially up-regulated in response to Sch stress. They were abundant in the medium-Sch system with the highest Fe(III) reduction, capable of complexing Fe(III), and underwent photochemical reactions via photo-induced charge transfer. The significant up-regulation of reducing sugars revealed the high energy requirement of Graesiella sp. MA1 under Sch stress. And first enriched KEGG pathway demonstrated the importance of sugar metabolism in Graesiella sp. MA1. Data acquired in this study provide novel insights into extreme acid stress adaptation of acid-tolerant algae and Sch, contributing to furthering understanding of AMD environments.

Preparation and properties of highly efficient flame-retardant Lyocell fabrics: Mitigating the acidity effect of phytic acid on the mechanical properties under pad-dry-curing process finishing conditions

The pad-dry-curing process involves padding with finishing liquid, pre-drying, and high-temperature baking. It is widely used in the dyeing and finishing field. For the field of flame-retardant finishing of fabrics, the use of phytic acid (PA) as a raw material can be highly effective. However, the extreme acidity of PA can cause damage to cellulose-based fabrics under high-temperature conditions. The development of PAMA, a compound formed by reacting PA with maltitol, can effectively alleviate the damage of PA to fabrics at high temperatures. PAMA not only exhibits excellent flame-retardant properties by slowing down flame propagation but also helps mitigate the acidic damage to Lyocell fabrics during the pad-dry-curing process, including an increase in the limiting oxygen index (31.9 %), a reduction in peak heat release rate (55 %), and a substantial increase in breaking force retention compared with those of the sample using pure PA as a flame retardant (300 %). Overall, this research presents a promising approach to the development of environmentally friendly flame retardants for textiles, highlighting the importance of balancing effectiveness with fabrics.

Anodic oxidation of esomeprazole in water by carbon coated titanium (C/Ti) electrode: Optimization and degradation analysis

AbstractEsomeprazole (ESO) is one of the proton pump inhibitors (PPIs) that is commonly used to treat extreme acidity and gastrointestinal irritation. Since it is used at a high rate, it is now classified as a pollutant of emerging concern (CEC). ESO gravely jeopardizes the health of living beings because it persists in water and wastewater sources even after standard treatment. Studies on the effective removal of PPIs, especially ESO, are scarce. In the current study, esomeprazole is disintegrated in water using electrochemical oxidation (EO). Titanium cathode with sodium sulfate electrolyte and carbon coated titanium (C/Ti) anode were used to apply EO. Through optimization studies utilizing COD measurement, it was discovered that 93% of the COD could be removed at pH 3, 60 mM sodium sulfate concentration, 300 min treatment period, and 115 mA cm−2 current density. Whereas TOC research revealed only 44% mineralization, HPLC‐PDA experiments revealed 100% ESO transformation. High resolution mass spectrometry (HRMS) studies were used to propose a degradation mechanism and pathway. The primary processes of degradation included desulfurization, thioperoxole group formation, sulfinyl benzimidazole group breakage, and demethylation. More than 20 reuses of the anode and cathode materials were possible without significantly lowering their oxidation efficiency.

Modular Protein Fibers with Outstanding High-Strength and Acid-Resistance Performance Mediated by Copper Ion Binding and Imine Networking.

Engineered protein fibers are promising biomaterials with diverse applications due to their tunable protein structure and outstanding mechanical properties. However, it remains challenging at the molecular level to achieve satisfied mechanical properties and environmental tolerance simultaneously, especially under extreme acid conditions. Herein, the construction of artificial fibers comprising chimeric proteins made of rigid amyloid peptide and flexible cationic elastin-like protein (ELP) module is reported. The amyloid peptide readily assembles into highly organized β-sheet structures that can be further strengthened by the coordination of Cu2+, while the flexible ELP module allows the formation of imine-based crosslinking networks. These double networks synergistically enhance the mechanical properties of the fibers, leading to a high tensile strength and toughness, overwhelming many reported recombinant spidroin fibers. Notably, the coordination of Cu2+ with serine residues could stabilize β-sheet structures in the fibers under acidic conditions, which makes the fibers robust against acid, thus enabling their successful utilization in gastric perforation suturing. This work highlights the customization of double networks at the molecular level to create tailored high-performance protein fibers for various application scenarios.

Unveiling a Technosol-based remediation approach for enhancing plant growth in an iron-rich acidic mine soil from the Rio Tinto Mars analog site

This paper explores the potential of Technosols made from non-hazardous industrial wastes as a sustainable solution for highly acidic iron-rich soils at the Rio Tinto mining site (Spain), a terrestrial Mars analog. These mine soils exhibit extreme acidity (pHH2O = 2.1–3.0), low nutrient availability (non-acid cation saturation < 20 %), and high levels of Pb (3420 mg kg−1), Cu (504 mg kg−1), Zn (415 mg kg−1), and As (319 mg kg−1), hindering plant growth and ecosystem restoration. To address these challenges, the study systematically analyzed selected waste materials, formulated them into Technosols, and conducted a four-month pot trial to evaluate the growth of Brassica juncea under greenhouse conditions. Technosols were tailored by adding varying weight percentages of waste amendments into the mine Technosol, specifically 10 %, 25 %, and 50 %. The waste amendments comprised a blend of organic waste (water clarification sludge, WCS) and inorganic wastes (white steel slag, WSS; and furnace iron slag, FIS). The formulations included: (T0) exclusively mine Technosol (control); (T1) 60 % WCS + 40 % WSS; (T2) 60 % WCS + 40 % FIS; and (T3) 50 % WCS + 16.66 % WSS + 33.33 % FIS. The analyses covered leachate quality, soil pore water chemistry, and plant response (germination and survival rates, plant height, and leaf number). Results revealed a significant reduction in leachable contaminant concentrations, with Pb (26.16 mg kg−1), Zn (4.94 mg kg−1), and Cu (2.29 mg kg−1) dropping to negligible levels and shifting towards less toxic species. These changes improved soil conditions, promoting seed germination and seedling growth. Among the formulations tested, Technosol T1 showed promise in overcoming mine soil limitations, enhancing plant adaptation, buffering against acidification, and stabilizing contaminants through precipitation and adsorption mechanisms. The paper stresses the importance of tailoring waste amendments to specific soil conditions, and highlights the broader implications of the Technosol approach, such as waste valorization, soil stabilization, and insights for Brassica juncea growth in extreme environments, including Martian soil simulants.

Multitier regulation of the E. coli extreme acid stress response by CsrA.

CsrA is an RNA-binding protein that regulates processes critical for growth and survival, including central carbon metabolism, motility, biofilm formation, stress responses, and expression of virulence factors in pathogens. Transcriptomics studies in Escherichia coli suggested that CsrA repressed genes involved in surviving extremely acidic conditions. Here, we examine the effects of disrupting CsrA-dependent regulation on the expression of genes and circuitry for acid stress survival and demonstrate CsrA-mediated repression at multiple levels. We show that this repression is critical for managing the trade-off between growth and survival; overexpression of acid stress genes caused by csrA disruption enhances survival under extreme acidity but is detrimental for growth under mildly acidic conditions. In vitro studies confirmed that CsrA binds specifically to mRNAs of structural and regulatory genes for acid stress survival, causing translational repression. We also found that translation of the top-tier acid stress regulator, evgA, is coupled to that of a small leader peptide, evgL, which is repressed by CsrA. Unlike dedicated acid stress response genes, csrA and its sRNA antagonists, csrB and csrC, did not exhibit a substantial response to acid shock. Furthermore, disruption of CsrA regulation of acid stress genes impacted host-microbe interactions in Caenorhabditis elegans, alleviating GABA deficiencies. This study expands the known regulon of CsrA to genes of the extreme acid stress response of E. coli and highlights a new facet of the global role played by CsrA in balancing the opposing physiological demands of stress resistance with the capacity for growth and modulating host interactions.IMPORTANCETo colonize/infect the mammalian intestinal tract, bacteria must survive exposure to the extreme acidity of the stomach. E. coli does this by expressing proteins that neutralize cytoplasmic acidity and cope with molecular damage caused by low pH. Because of the metabolic cost of these processes, genes for surviving acid stress are tightly regulated. Here, we show that CsrA negatively regulates the cascade of expression responsible for the acid stress response. Increased expression of acid response genes due to csrA disruption improved survival at extremely low pH but inhibited growth under mildly acidic conditions. Our findings define a new layer of regulation in the acid stress response of E. coli and a novel physiological function for CsrA.

CO2 - extraction of glycyrrhizic acid from licorice root: Optimization of extraction conditions using RSM

Extraction of GA (glycyrrhizic acid) from licorice roots was carried out utilizing SC-CO2 with etilen as a dissolvable. Tests and recreations were assigned utilizing RSM. Licorice root extricate was analyzed by chromatography and AAS. The RSM plan was utilized to optimize the SCE factors and Glycyrrhizic Acid surrender. The most extreme Glycyrrhizic Acid surrender was watched beneath conditions of 10,9 MPa, 90,5 and 49,5 °C, 93 min and a stream of 1,69 and 1,49 ml/min CO2 utilizing RSM, separately. Agreeing to RSM, the R2 and adjusted R2 model are 95,9% and 92,3% individually. The precision of the GA surrender demonstrate is affirmed by triplet tests, giving an normal extraction abdicate of 51,9 ± 1,19 %, individually, for RSM.

The Leaching Process of Acid Sulphate Soil by One-and Two-Way Flow Systems in the Katingan Swamp Irrigation Area

The Katingan Swamp Irrigation Area, established in 1980, has an important role in supporting food security in Indonesia. It needs to be reclaimed to increase agricultural production, especially for leaching acid sulphate soil. The swamp irrigation area was expanded and rehabilitated so that the two-way flow became a one-way flow system to support the leaching process. This study aims to assess the discharge and water quality alterations in the Katingan main channel after the change of flow system. The aim is achieved by comparing the outcomes obtained from one-way and two-way flow simulations. The simulation used a mathematical model based on water level, water quality, and land topography data collected in the field. According to the findings, the two-way system demonstrates that fresh water from the river has not been able to improve water quality (pH) at the end of the primary channel, thereby leading to extreme acidity in those regions. Meanwhile, a one-way flow facilitates efficient circulation and delivers fresh water to the farthest service regions. Effective water circulation is important to enhance water quality in agricultural areas that have recently expanded. The current study focuses on mid-irrigation. Future research may cover the entire irrigation network for in-depth analysis.

Self-powered sensors for flexible electronic skins capable of self-healing under multiple extreme environments

With the advancements in electronic skins (E-skins) and communication technologies, the applicability of sensors in extreme environments poses significant challenges. While various sensors have been reported, maintaining electrical output performance without external power source and self-healing capability across multiple extreme environments remains a hurdle. Herein, we present flexible, self-healing, and harsh environment-resistant self-powered sensors for E-skins, the self-healing capabilities of which are virtually invulnerable in diverse extreme environments, including underwater, saline, oxidized, alkali, and acid conditions, as well as low and high temperatures. The self-powered sensors are composed of self-healing polyurea (SH-PUrea) and Ag nanowires (AgNWs). Since physical entanglements that are less susceptible to environmental influences are introduced in SH-PUrea, the self-powered sensors exhibit exceptional self-healing performance without degradation of the output signals, regardless of the ambient conditions or extreme environments encountered. Specifically designed in a 3 × 3 pixel array structure, the self-powered sensors are ideal for E-skins that can adapt to sweaty and underwater environments. The detection of pressure position and underwater communication can be achieved by analyzing the electrical signals from the sensor array. This work introduces a novel strategy for enhancing the extreme environment-resistance and durability of flexible devices.

Genomic insight and physiological characterization of thermoacidophilic Alicyclobacillus isolated from Yellowstone National Park.

Alicyclobacillus has been isolated from extreme environments such as hot springs, volcanoes, as well as pasteurized acidic beverages, because it can tolerate extreme temperatures and acidity. In our previous study, Alicyclobacillus was isolated during the enrichment of methane oxidizing bacteria from Yellowstone Hot Spring samples. Physiological characterization and genomic exploration of two new Alicyclobacillus isolates, AL01A and AL05G, are the main focus of this study to identify their potential relationships with a thermoacidophilic methanotroph (Methylacidiphilum) isolated from the same hot spring sediments. In the present study, both Alicyclobacillus isolates showed optimal growth at pH 3.5 and 55°C, and contain ω-alicyclic fatty acids as a major lipid (ca. 60%) in the bacterial membrane. Genomic analysis of these strains revealed specific genes and pathways that the methanotroph genome does not have in the intermediary carbon metabolism pathway such as serC (phosphoserine aminotransferase), comA (phosphosulfolactate synthase), and DAK (glycerone kinase). Both Alicyclobacillus strains were also found to contain transporter systems for extracellular sulfate (ABC transporter), suggesting that they could play an important role in sulfur metabolism in this extreme environment. Genomic analysis of vitamin metabolism revealed Alicyclobacillus and Methylacidiphilum are able to complement each other's nutritional deficiencies, resulting in a mutually beneficial relationship, especially in vitamin B1(thiamin), B3 (niacin), and B7 (biotin) metabolism. These findings provide insights into the role of Alicyclobacillus isolates in geothermal environments and their unique metabolic adaptations to these environments.

Detection of Extreme Acidity Based on Carbon Dots: One‐Step Gram‐Scaled Syntheses, Ratiometric Emission Photoluminescent Probe, and Hand‐Held Visual Detection

AbstractIt is a significant challenge to develop acidity probes suitable for use in extremely acidic conditions, especially to achieve real‐time on‐site detection. In this work, carbon dots (CDs) are synthesized on a gram‐scale under mild conditions using 3‐phenylpropionaldehyde as precursors. The CDs have excellent robustness, showing distinguished anti‐photobleaching and ionic stability. Dramatically, a visual transition of the fluorescent color of CDs from cyan to orange is observed when the concentration of H+ ([H+]) increased under high acidity conditions, owing to the generation of another emission peak in the red‐light region. Taking advantage of the optical properties, CDs are designed as a ratiometric sensing platform for the detection of extreme acidity. Furthermore, the platform for [H+] possesses high selectivity and excellent anti‐interference capability. In extremely acidic wastewater, I595 nm/I480 nm and [H+] maintain a very good linear relationship (R2 = 0.996). Moreover, a smartphone is employed to obtain the red‐green‐blue (RGB) values of the samples to realize hand‐held detection. By measuring the R/G, the platform exhibits ultrasensitive recognition of [H+] in the range of 1–9 mol L−1 with R2 of 0.992. This work paves an avenue for the design of rapid and on‐site CDs based sensors for critical environmental applications.

Expression, Purification and Characterization of a Novel Rusticyanin from the Psychrotolerant Acidithiobacillus ferrivorans

Rusticyanin plays a crucial role in ferrous oxidation of sulfide minerals during bioleaching for industrial metal extraction. Diverse isoforms of rusticyanin have been found, but until now, except for type-A rusticyanin, other isoforms or sources of rusticyanin have been scarcely investigated. Here, a rusticyanin (gene locus 0470) from the psychrophilic Acidithiobacillus ferrivorans was gene-cloned, expressed, purified, and assembled in vitro. All forms of the protein exhibit extreme acid stability, even at pH 0.3. The stability of the protein is obviously enhanced after binding of the copper cofactor; the oxidation state is more stable than the reduced state. The protein has characteristic UV-vis peaks and EPR signals similar to type-A or type-B rusticyanin but is different with a small position shift and an obvious intensity change. The vibrational spectrum of the apoprotein was more different than these between the oxidation and reduced states of the protein. The ferrous oxidation kinetic rate constant of the protein is obviously faster than that of both the type-A and type-B rusticyanins previously reported. Further bioinformatics analysis reveal their changes in sequence and molecule: the mutations related to the peculiar shield belt mostly account for the variation in the properties of the protein, and the classification of the protein as a new isoform, type-C rusticyanin, is proposed.

Au Nanoparticles Decorated CoP Nanowire Array: A Highly Sensitive, Anticorrosive, and Recyclable Surface-Enhanced Raman Scattering Substrate.

Metal-semiconductor composites are promising candidates for surface-enhanced Raman scattering (SERS) substrates, but their inert basal plane, poor active sites, and limited stability hamper their commercial prospects. Herein, we report a three-dimensional CoP nanowire array decorated with Au nanoparticles on carbon cloth (Au@CoP/CC) as a self-supporting flexible SERS substrate. The Au nanoparticles spontaneously grew on the surface of the CoP nanowire array to form efficient SERS hot spots by a redox reaction with HAuCl4 without any additional reducing agents. Such Au@CoP/CC substrate exhibited a limit of detection of 10-11 M using rhodamine 6G as a model dye with outstanding corrosion resistance ability even under extreme acid and alkali conditions, which is better than many recently reported Au-based SERS substrates. Finite-difference time-domain simulation results demonstrated that Au@CoP/CC can provide a high density of regions with intense local electric field enhancement. Moreover, Au@CoP/CC can degrade target organic dyes for the self-cleaning and reproduction of SERS-active substrates under visible light irradiation. This work provides a novel means of using the plasmonic metal-transition metal phosphide composites for high-performance SERS sensing and photodegradation.

Recent Development in Advance Ceramic Materials and Understanding the Mechanisms of Thermal Barrier Coatings Degradation

AbstractMetallic alloys' behavior at high temperatures, especially their response to corrosion and formation of protective surface layers, has long been a focus of scientific inquiry. Although certain alloy compositions require an initiation period before hot corrosion advances to the propagation stage, no combination of alloys can be considered impervious to hot corrosion indefinitely. The capacity of nickel-based materials to tolerate extreme circumstances such high temperatures, acidity, corrosion, and scratching is highly valued. However, they are unable to satisfy the strict demands of today's high-temperature applications. The durability of thermal barrier coatings (TBCs), which are prone to oxidation, rust, and degradation from sulphates and foreign object damage, has been the subject of recent study. For sophisticated ceramic materials exposed to high temperatures, hot rust degradation poses a considerable challenge. The main objective of this study is to investigate the effects of severe degradation on several advanced ceramic material types and their level of advancement. The purpose of the inquiry is to comprehend the deteriorating processes at the long term working condition, including the function of oxidation and liquid salts. Additionally, we investigate the effects of temperature, environment, and contact duration on the heated weathering behavior of earthenware. Finally, we discuss strategies for mitigating hot corrosion degradation in ceramics, such as protective coatings like new design of TBCs, doping, and composition optimization. This paper aims to offer a thorough understanding of the hot corrosion behavior of ceramics, which is crucial for developing durable materials suitable for high-temperature applications. Additionally, it explores the fabrication of protective coatings and addresses the challenges faced in this regard. The insights gained from this research can contribute to the advancement of resilient ceramic fabrics and the development of effective protective coatings.

The genesis of an extremely acidic perched aquifer within roasted pyrite waste in a fully urbanized area (Zaragoza, Spain)

Contaminated groundwater is a serious problem in developed countries. The abandonment of industrial waste may lead to acid drainage affecting groundwater and severely impacting the environment and urban infrastructure. We examined the hydrogeology and hydrochemistry of an urban area in Almozara (Zaragoza, Spain); built over an old industrial zone, with pyrite roasting waste deposits, there were acid drainage problems in underground car parks. Drilling and piezometer construction, and groundwater samples revealed the existence of a perched aquifer within old sulfide mill tailings, where the building basements interrupted groundwater flow, leading to a water stagnation zone that reached extreme acidity values (pH < 2). A groundwater flow reactive transport model was developed using PHAST to reproduce flow and groundwater chemistry, in order to be used as a predictive tool for guiding remediation actions. The model reproduced the measured groundwater chemistry by simulating the kinetically controlled pyrite and portlandite dissolution. The model predicts that an extreme acidity front (pH < 2), coincident with the Fe (III) pyrite oxidation mechanism taking dominance, is propagating by 30 m/year if constant flow is assumed. The incomplete dissolution of residual pyrite (up to 18 % dissolved) predicted by the model indicates that the acid drainage is limited by the flow regime rather than sulfide availability. The installation of additional water collectors between the recharge source and the stagnation zone has been proposed, together with periodic pumping of the stagnation zone. The study findings are expected to serve as a useful background for the assessment of acid drainage in urban areas, since urbanization of old industrial land is rapidly increasing worldwide.

The potential of legume cover crops and soil microbes for gold mine tailings revegetation

Mercury (Hg) is commonly utilized in artisanal gold mining on Buru Island; the Hg-contaminated tailing possibly contaminates the agricultural land nearby. In general, tailings contain very low organic carbon and plant nutrients but are high in mercury and have extreme soil acidity. The objective of this study was to observe the growth of various legume cover crops (LCC) and the change of Hg in tailing inoculated with &lt;em&gt;Azotobacter-Trichoderma&lt;/em&gt;. The field trial was conducted on Buru Island of Maluku by using a split-plot design with three replications. The main plot was LCC species, composed of &lt;em&gt;Centrosema pubescens&lt;/em&gt; (CP), &lt;em&gt;Mucuna &lt;/em&gt;sp.&lt;em&gt; (&lt;/em&gt;MC), and &lt;em&gt;Crotalaria &lt;/em&gt;sp. (CR); the subplots were microbial inoculants composed of two formulations of &lt;em&gt;Azotobacter-Trochoderma&lt;/em&gt; inoculants. The results showed that the &lt;em&gt;Mucuna &lt;/em&gt;sp. and consortia &lt;em&gt;Azotobacter-Trichoderma&lt;/em&gt; (2:1) had the highest survival rate in the tailings and Hg uptake by 8.83 mg kg&lt;sup&gt;-1&lt;/sup&gt; per plant. Consortia &lt;em&gt;Azotobacter-Trichoderma&lt;/em&gt; inoculant with the composition of 2:1 (v:v) was able to increase soil pH, total bacterial population, LCC biomass, and Hg uptake by LCC plants. The highest Hg removal effectivity was observed in the plot treated with &lt;em&gt;Crotalaria &lt;/em&gt;sp. and in a plot with &lt;em&gt;Azotobacter-Trichoderma&lt;/em&gt; (2:1), which was 34.0% and 33.6%, respectively.

Granular and powdered lime improves soil properties and maize (Zea mays l.) performance in humic Nitisols of central highlands in Kenya

Acidic soils pose a major challenge for crop production in heavily weathered tropical soils, especially due to the high toxicity of aluminum (Al), low cation exchange capacity, and low availability of phosphorus (P) to plants. Lime application was recommended to alleviate soil acidity problems. Granular CaCO3 lime was introduced into the Kenyan market as an alternative to powdered CaCO3 and CaO-lime for small Kenyan farms, providing uniform distribution and efficient application. The aim of this study was therefore to investigate the effectiveness of different types of powdered and granular lime individually and in combination with mineral fertilizers in improving soil properties and maize yield. The study was conducted at two sites, Kirege (extremely acidic) and Kangutu (moderately acidic). Experiments were conducted in a randomized complete block design repeated four times in two consecutive seasons: long rain (LR) in 2016 and short rain (SR) in 2016. Three types of lime were applied before planting. Selected chemical properties of the soil were analyzed before and after the experiment. Maize and stover yield data were collected and analyzed. Results showed that lime application significantly increased soil pH and decreased exchangeable acidity. Powdered calcium carbonate (CaCO3) showed the highest pH increase in both extreme (+19%) and moderate (+14%) acid sites. All types of lime and fertilizer applications alone significantly increased the available soil P at both the seasonal and site levels. However, maize grain yield was lower with fertilizer alone or lime alone than with lime and fertilizer combination. Powdered CaCO3+ fertilizer was found to give the highest grain yields on both very acidic (5.34 t ha-1) and moderately (3.71 t ha-1) acid sites. In the study, combining powdered CaCO3 lime with fertilizers was most effective in improving acidic soils by decreasing soil acidity and increasing available phosphorus, which ultimately increased grain yield. The results of this study recommend the use of powdered CaCO3 as an effective and practical solution for farmers facing soil acidification problems.

A programmable oral bacterial hydrogel for controllable production and release of nanovaccine for tumor immunotherapy

Oral protein vaccines are mainly used to prevent the infection of intestinal pathogens in clinic due to their high safety and strong compliance. However, it is necessary to design the efficient delivery systems to overcome the harsh gastrointestinal environment in the application process. Here we established a programmable oral bacterial hydrogel system for spatiotemporally controllable production and release of nanovaccines. The system was divided into three parts: (1) Engineered bacteria were encapsulated in chitosan-sodium alginate microcapsules, which offered protection against the extreme acid conditions in the stomach. (2) Microcapsules were dissolved, and then engineered bacteria were released and colonized in the intestine. (3) The release of nanovaccines was controlled periodically by a synchronous lysis genetic circuit for tumor immunotherapy. Compared to control groups, tumor volume of subcutaneous tumor-bearing mice treated with bacterial microgels releasing optimized nanovaccine was almost inhibited by 75% and T cell response was activated at least 2-fold. We believe that this programmable bacterial hydrogel will offer a promising way for the application of oral nanovaccines.