Insoluble Form Research Articles

Effects of Modified Distillers' Grains Biochar on Cadmium Forms in Purple Soil and Cadmium Uptake by Rice

Biochar and modified biochar have been widely used as remediation materials in heavy metal-contaminated agricultural soils. In order to explore economical and effective materials for the remediation of cadmium (Cd)-contaminated acidic purple soil, distillers 'grains were converted into distillers' grains biochar (DGBC) and modified using nano-titanium dioxide (Nano-TiO2) to produce two types of modified DGBCs:TiO2/DGBC and Fe-TiO2/DGBC. A rice pot experiment was used to investigate the effects of different biochar types and application rates (1%, 3%, and 5%) on soil properties, nutrient content, Cd bioavailability, Cd forms, rice growth, and Cd accumulation. The results showed that:① DGBC application significantly increased soil pH, cation exchange capacity (CEC), and nutrient content, with TiO2/DGBC and Fe-TiO2/DGBC exhibiting better effects. ② DGBC and modified DGBCs transformed Cd from soluble to insoluble forms, increasing residual Cd by 1.22% to 18.46% compared to that in the control. Cd bioavailability in soil decreased significantly, with available cadmium being reduced by 11.81% to 23.67% for DGBC, 7.64% to 43.85% for TiO2/DGBC, and 19.75% to 55.82% for Fe-TiO2/DGBC. ③ DGBC and modified DGBCs increased rice grain yield, with the highest yields observed at a 3% application rate:30.60 g·pot-1 for DGBC, 37.85 g·pot-1 for TiO2/DGBC, and 39.10 g·pot-1 for Fe-TiO2/DGBC, representing 1.13, 1.40, and 1.44 times the control yield, respectively. Cd content in rice was significantly reduced, with grain Cd content ranging from 0.24 to 0.30 mg·kg-1 for DGBC, 0.16 to 0.26 mg·kg-1 for TiO2/DGBC, and 0.14 to 0.24 mg·kg-1 for Fe-TiO2/DGBC. Notably, Cd content in rice grains fell below the food safety limit of 0.2 mg·kg-1 (GB2762-2022) at 5% for TiO2/DGBC and 3% and 5% for Fe-TiO2/DGBC. In conclusion, Nano-TiO2 modified DGBC effectively reduced the bioavailability of soil Cd through its own adsorption and influence on soil Cd forms distribution, thus reducing the absorption of Cd by rice and simultaneously promoting rice growth and improving rice yield. It is a type of Cd-contaminated soil remediation material with a potential application prospect. The results can provide scientific basis for farmland restoration and agricultural safety production of Cd-contaminated acidic purple soil.

Innovative method for producing plant-based meat analogs: Acid/calcium-induced internal gelation of potato protein/alginate composites

When creating plant-based meat analogs, it is often challenging to mimic the structural and textural attributes of real meat products during the cooking process. In this study, we investigated the potential of using potato protein/calcium alginate composite gels to formulate plant-based meat analogs. These gels provide a semi-solid texture at ambient temperature that remains intact during cooking because the electrostatic crosslinks are resistant to heat. Composite gels consisting of potato protein (10 wt%) and alginate (0–2 wt%) were prepared using the internal gelation method. This method involves dispersing an insoluble form of calcium (CaHPO4) throughout the protein-polysaccharide matrix and then using glucono-delta-lactone (GDL) to slowly lower the pH, thereby releasing the Ca2+ ions evenly throughout the system. The calcium alginate increased the strength of the potato protein gels and provided structural resistance to heat. Appreciable water loss occurred during cooking for simple calcium alginate gels, but this was prevented when potato proteins were present. Increasing the alginate concentration from 0 to 1.5 % increased the strength of the composite gels but higher levels promoted phase separation and network disruption, which reduced the gel strength. Heating did not appreciably alter the microstructure of the composite gels, but it did alter that of the pure potato protein gels. Finally, the potential of the composite gels as plant-based meat analogs was assessed by comparing their thermal denaturation and textural properties to those of real chicken breast. The potato protein/alginate composites were shown to simulate the thermal denaturation and textural changes of real chicken during the cooking process. Overall, our results suggest that calcium alginate gels may be useful in the formulation of plant-based meat products with improved cooking properties.

Soluble and hydrolyzable phenolic compounds in date fruits (Phoenix dactylifera L.) by UPLC-QTOF-MS/MS and UPLC-DAD

Phenolic compounds in plant foods exist in soluble, hydrolyzable, and insoluble forms. This study is the first to analyze both soluble (extracted using 80 % methanol) and hydrolyzable (extracted using ethyl acetate after alkaline hydrolysis) phenolics in 18 date cultivars. The phenolic compounds were identified and quantified using ultra-high-performance liquid chromatography with quadrupole time-of-flight mass spectrometry and diode array detectors. A total of 59 peaks were detected, of which 45 were identified while 14 remained unidentified. The concentrations of the soluble and hydrolyzable phenolics ranged from 27.5–54.0 and 24–78.5 mg/100 g fresh weight, respectively. Gallic acid and ferulic acid predominated in the soluble and hydrolyzable fractions, quercetin and taxifolin were predominant in the soluble fraction, while caffeic acid and chlorogenic acid were abundant in the hydrolyzable fraction. The hydrolyzable phenolics were found to contribute significantly to the total phenolic content of date fruits pointing to the need to include them in the analysis of total phenolic compounds in foods.

Effect of astaxanthin in type-2 diabetes -induced APPxhQC transgenic and NTG mice

ObjectivesAggregation and misfolding of amyloid beta (Aβ) and tau proteins, suggested to arise from post-translational modification processes, are thought to be the main cause of Alzheimer's disease (AD). Additionally, a plethora of evidence exists that links metabolic dysfunctions such as obesity, type 2 diabetes (T2D), and dyslipidemia to the pathogenesis of AD. We thus investigated the combinatory effect of T2D and human glutaminyl cyclase activity (pyroglutamylation), on the pathology of AD and whether astaxanthin (ASX) treatment ameliorates accompanying pathophysiological manifestations. MethodsMale transgenic AD mice, APPxhQC, expressing human APP751 with the Swedish and the London mutation and human glutaminyl cyclase (hQC) enzyme and their non-transgenic (NTG) littermates were used. Both APPxhQC and NTG mice were allocated to 3 groups, control, T2D-control, and T2D-ASX. Mice were fed control or high fat diet ± ASX for 13 weeks starting at an age of 11–12 months. High fat diet fed mice were further treated with streptozocin for T2D induction. Effects of genotype, T2D induction, and ASX treatment were evaluated by analysing glycemic readouts, lipid concentration, Aβ deposition, hippocampus-dependent cognitive function and nutrient sensing using immunosorbent assay, ELISA-based assays, western blotting, immunofluorescence staining, and behavioral testing via Morris water maze (MWM), respectively. ResultsAPPxhQC mice presented a higher glucose sensitivity compared to NTG mice. T2D-induced brain dysfunction was more severe in NTG compared to the APPxhQC mice. T2D induction impaired memory functions while increasing hepatic LC3B, ABCA1, and p65 levels in NTG mice. T2D induction resulted in a progressive shift of Aβ from the soluble to insoluble form in APPxhQC mice. ASX treatment reversed T2D-induced memory dysfunction in NTG mice and in parallel increased hepatic pAKT while decreasing p65 and increasing cerebral p-S6rp and p65 levels. ASX treatment reduced soluble Aβ38 and Aβ40 and insoluble Aβ40 levels in T2D-induced APPxhQC mice. ConclusionsWe demonstrate that T2D induction in APPxhQC mice poses additional risk for AD pathology as seen by increased Aβ deposition. Although ASX treatment reduced Aβ expression in T2D-induced APPxhQC mice and rescued T2D-induced memory impairment in NTG mice, ASX treatment alone may not be effective in cases of T2D comorbidity and AD.

Antibodies anti-rFilF protein has anti-biofilm activity against carbapenem-resistant Acinetobacter baumannii

Acinetobacter baumannii is an opportunistic bacterium that causes infection in several sites. Carbapenem-resistant A. baumannii strains (CRAb) lead the World Health Organization's list of 12 pathogens considered a priority for developing new antimicrobials. The pathogenicity of A. baumannii is related to the different virulence factors employed in the colonization of biotic and abiotic surfaces, biofilm formation and multidrug resistance. We analyze the outer membrane protein FilF from A. baumannii in silico and produce it in recombinant form (rFilF). rFilF protein was successfully expressed in Escherichia coli BL21 Star in an insoluble form. Immunization with rFilF induced significant anti-rFilF IgG antibody production in mice, detected by indirect enzyme-linked immunosorbent assay, since the first evaluation until 49th. On the last experimentation day, the predominant immunoglobulin found was IgG1 followed by IgG2a, IgG2b, IgM, IgG3, and IgA. We observe that interleukins 4 and 10 show significant production after the 28th day of experimentation in mice immunized with rFilF. Anti-rFilF pAbs were able to inhibit biofilm formation in nine CRAb strains evaluated, and in the standard strain ATCC® 19606. These results demonstrate the anti-biofilm activity of anti-rFilF antibodies, promising in the development of a non-antibiotic approach based on the control of CRAb strains.

Removal of Cu(II) by sodium hexametaphosphate and nano zero-valent iron modified calcium bentonite: characteristic, adsorption performance and mechanism

Cu (II) is a toxic heavy metal commonly identified in groundwater contaminants. Bentonite-based cutoff wall is the most used method in isolating and adsorbing contaminants, while the bentonite in it easily to fail due to Cu(II) exchange. This study synthesized a novel material through the modification of calcium bentonite (CaB) utilizing sodium hexametaphosphate (SHMP) and nano zero-valent iron (NZVI). The characteristics, adsorption performance, and mechanism of the NZVI/SHMP-CaB were investigated comprehensively. The results showed that SHMP can disperse CaB and reduce flocculation, while NZVI can be further stabilized without agglomeration. The best adsorption performance of NZVI/SHMP-CaB could be obtained at the dosage of 2% SHMP and 4% NZVI. The NZVI/SHMP-CaB exhibited an outstanding removal efficiency of over 60% and 90% at a high Cu(II) concentration (pH = 6, Cu(II) = 300 mg/L) and acidic conditions (pH = 3–6, Cu(II) = 50 mg/L), respectively. The adsorption of Cu(II) by NZVI/SHMP-CaB followed a pseudo-second-order kinetic model, and fitting results from the Freundlich isothermal model suggested that the adsorption process occurred spontaneously. Besides the rapid surface adsorption on the NZVI/SHMP-CaB and ion exchange with interlayer ions in bentonite, the removal mechanism of Cu(II) also involved the chemical reduction to insoluble forms such as Cu0 and Cu2O. The generated FePO4 covered the surface of the homogenized NZVI particles, enhancing the resistance of NZVI/SHMP-CaB to acidic and oxidative environments. This study indicates that NZVI/SHMP-CaB is a promising alternative material which can be used for heavy metal removal from contaminated soil and water.

Co-occurrence patterns of gut microbiome, antibiotic resistome and the perturbation of dietary uptake in captive giant pandas

The microbiome is a key source of antibiotic resistance genes (ARGs), significantly influenced by diet, which highlights the interconnectedness between diet, gut microbiome, and ARGs. Currently, our understanding is limited on the co-occurrence among gut microbiome, antibiotic resistome in the captive giant panda and the perturbation of dietary uptake, especially for the composition and forms in dietary nutrition. Here, a qPCR array with 384 primer sets and 16 S rRNA gene amplicon sequencing were used to characterize the antibiotic resistome and microbiomes in panda feces, dietary bamboo, and soil around the habitat. Diet nutrients containing organic and mineral substances in soluble and insoluble forms were also quantified. Organic and mineral components in water-unextractable fractions were 7.5 to 139 and 637 to 8695 times higher than those in water-extractable portions in bamboo and feces, respectively, while the latter contributed more to the variation (67.5 %) of gut microbiota. Streptococcus, Prevotellaceae, and Bacteroides were the dominant genera in giant pandas. The ARG patterns in panda guts showed higher diversity in old individuals but higher abundance in young ones, driven directly by the bacterial community change and mobile genetic element mediation and indirectly by dietary intervention. Our results suggest that dietary nutrition mainly accounts for the shift of gut microbiota, while bacterial community and mobile genetic elements influenced the variation of gut antibiotic resistome.

Improving Soluble Phenolic Profile and Antioxidant Activity of Grape Pomace Seeds through Fungal Solid-State Fermentation.

Grape pomace seeds contain abundant phenolic compounds, which are also present in both soluble and insoluble forms, similar to many other plant matrices. To further increase the extractable soluble phenolics and their antioxidant activities, grape pomace seeds were fermented with different fungi. Results showed that solid-state fermentation (SSF) with Aspergillus niger, Monascus anka, and Eurotium cristatum at 28 °C and 65% humidity had a significantly positive impact on the release of soluble phenolics in grape pomace seeds. Specifically, SSF with M. anka increased the soluble phenolic contents by 6.42 times (calculated as total phenolic content) and 6.68 times (calculated as total flavonoid content), leading to an overall improvement of antioxidant activities, including DPPH (increased by 2.14 times) and ABTS (increased by 3.64 times) radical scavenging activity. Furthermore, substantial changes were observed in the composition and content of individual phenolic compounds in the soluble fraction, with significantly heightened levels of specific phenolics such as chlorogenic acid, syringic acid, ferulic acid, epicatechin gallate, and resveratrol. Notably, during M. anka SSF, positive correlations were identified between the soluble phenolic content and hydrolase activities. In particular, there is a strong positive correlation between glycosidase and soluble phenols (r = 0.900). The findings present an effective strategy for improving the soluble phenolic profiles and bioactivities of grape pomace seeds through fungal SSF, thereby facilitating the valorization of winemaking by-products.

Effects of wollastonite and phosphate treatments on cadmium bioaccessibility in pak choi (Brassica rapa L. ssp. chinensis) grown in contaminated soils.

Cadmium (Cd) contamination of soil can strongly impact human health through the food chain due to uptake by crop plants. Inorganic immobilizing agents such as silicates and phosphates have been shown to effectively reduce Cd transfer from the soil to cereal crops. However, the effects of such agents on total Cd and its bioaccessibility in leafy vegetables are not yet known. Pak choi (Brassica rapa L. ssp. chinensis) was here selected as a representative leafy vegetable to be tested in pots to reveal the effects of silicate-phosphate amendments on soil Cd chemical fractions, total plant Cd levels, and plant bioaccessibility. The collected Cd contaminated soil was mixed with control soil at 1:0, 1:1, 1:4, 0:1 with a view to Cd high/moderate/mild/control soil samples. Three heavy metal-immobilizing agents: wollastonite (W), potassium tripolyphosphate (KTPP), and sodium hexametaphosphate (SHMP) were added to the soil in order to get four different treatment groups, i.e., control (CK), application of wollastonite alone (W), wollastonite co-applied with KTPP (WKTPP), application of wollastonite co-applied with SHMP (WSHMP) for remediation of soils with different levels of Cd contamination. All three treatments increased the effective bio-Cd concentration in the soils with varying levels of contamination, except for W under moderate and heavy Cd contamination. The total Cd concentration in pak choi plants grown in mildly Cd-contaminated soil was elevated by 86.2% after WKTPP treatment compared to the control treatment could function as a phytoremediation aid for mildly Cd-contaminated soil. Using an in vitro digestion method (physiologically based extraction test) combined with transmission electron microscopy, silicate and phosphorus agents were found to reduce the bioaccessibility of Cd in pak choi by up to 66.13% with WSHMP treatment. Application of silicate alone reduced soil bio-Cd concentration through the formation of insoluble complexes and silanol groups with Cd, but the addition of phosphate may have facilitated Cd translocation into pak choi by first co-precipitating with Ca in wollastonite while simultaneously altering soil pH. Meanwhile, wollastonite and phosphate treatments may cause Cd to be firmly enclosed in the cell wall in an insoluble form, reducing its translocation to edible parts and decreasing the bioaccessibility of Cd in pak choi. This study contributes to the mitigation of Cd bioaccessibility in pak choi by reducing soil Cd concentration through in situ remediation and will help us to extend the effects of wollastonite and phosphate on Cd bioaccessibility to other common vegetables. Therefore, this study thus reveals effective strategies for the remediation of soil Cd and the reduction of Cd bioaccessibility in crops based on two indicators: total Cd and Cd bioaccessibility. Our findings contribute to the development of methods for safer cultivation of commonly consumed leafy vegetables and for soil remediation.

Research on the extraction of rare earth elements from ash-slag waste

The research investigates the patterns of rare earth elements (REE) extraction from ash-slag waste of thermal power plants using sintering processes. The aim of the study was to determine the optimal parameters for the process: the composition of the flux, the ratio of the sintering flux to the waste, and the sintering temperature. It has been shown that the change in the type of sintering reagent, its ratio to the waste, and the process temperature significantly affect the degree of REE extraction from the insoluble form in ash-slag to the soluble form in sinter. The optimal sintering temperatures (300–4500C) for the extraction of REE from ash-slag waste have been determined. The influence of various sintering reagents on the process of REE extraction from ash-slag waste has been investigated. It has been shown that the use of sodium hydroxide as a sintering reagent allows increasing the degree of REE extraction from waste up to 100%. Based on the analysis of the obtained experimental data, the main technological parameters of REE extraction in sinter have been determined.

The Role of Biochemical Markers in Cataractogenesis. Literature Review

Lens transparency is determined by both cellular and subcellular levels of its organization. Abnormalities of its size, uniformity of shape and correct arrangement of the fibers lead to the scattering of light falling on the lens. At the same time, its normal transparent proteins turn into a cloudy, coagulated, insoluble form, and undergo denaturation. Therefore, the preservation of lens transparency is possible only with a certain chemical composition, achieved by a strict balance of all metabolism links. There are many different hypotheses about the disease etiology. It is known that intraocular fluid has a low content of proteins and an increased concentration of chloride-, lactate-, ascorbatanions in its composition, in contrast to blood plasma. It cannot be ruled out that this is due to the selective permeability of the blood–ocular barrier, which consists of non-pigmented epithelial cells of the ciliary body. In addition, the modification of molecular composition and constitutional imbalance in the intraocular fluid often causes of pathological processes development in the anterior segment of the eye. The blood-ocular barrier makes the eye an immune-privileged organ. However, many diseases, surgical interventions and eye injuries can lead to blood-ocular barrier damage. This causes to inflammatory effector cells and molecules inducing a cascade of reactions, which in turn results in irreversible fibrotic changes in the lens substance. In this regard, it becomes necessary to search for new reliable methods of determining the level of certain biochemical agents in intraocular structures, as well as establishing reference values for strategically important biomarkers of cataract development. This review presents modern views on biochemical markers imbalance in the anterior chamber aqueous humor and the lens, which contributes to its substance opacity.

BIOEXTRACTION OF IRON THROUGH Bacillus sp. SP10 FROM MINERAL OXIDE AND ITS APPLICATION AS PLANT MICRONUTRIENT

Iron is an essential micronutrient for all living organisms because of its critical 
 role in metabolic processes. In plants it plays a key role in the synthesis of 
 chlorophyll, some vital enzymatic and metabolic processese. However, most of 
 the iron in nature is present as precipitates or in insoluble forms. Therefore, 
 biological mechanism has been employed to mineralize Fe(III) oxides into 
 Fe(II) through microbial action to increase the availability of soluble iron. An 
 iron reducing bacterial strain was isolated based on its tolerant limits and iron 
 mineralizing ability. The strain Bacillus sp. SP10 effectively mineralized iron 
 in synthetic medium possessing 1% starch and pH 7. In a 25 day’s column 
 study, the soluble Fe(II) as micronutrient showed a gradual increase in each 
 seepage collected from different treatment columns. Similarly, the plants 
 grown on soil obtained from treatment D (i.e. 1% starch + 1% Bacillus sp. 
 SP10 inoculum + 0.25% anthraquinone-2,6-disulphonate) column displayed 
 good growth and maximum shoot length, mainly due to the increased 
 accessibility of iron through microbial mineralization. The mineralization of 
 Fe in soil was established through SEM and EDX analysis.

Reducing the accumulation of cadmium and phenanthrene in rice by optimizing planting spacing: Role of low-abundance but core rhizobacterial communities

Optimizing planting spacing is a common agricultural practice for enhancing rice growth. However, its effect on the accumulation of cadmium (Cd) and phenanthrene (Phen) in soil-rice systems and the response mechanisms of rhizobacteria to co-contaminants remain unclear. This study found that reducing rice planting spacing to 5 cm and 10 cm significantly decreased the bioavailability of Cd (by 7.9 %–29.5 %) and Phen (by 12.9 %–47.6 %) in the rhizosphere soil by converting them into insoluble forms. The increased accumulation of Cd and Phen in roots and iron plaques (IPs) ultimately led to decreased Cd (by 32.2 %–39.9 %) and Phen (by 4.2 %–17.3 %) levels in brown rice, and also significantly affected the composition of rhizobacteria. Specifically, reducing rice planting spacing increased the abundance of low-abundance but core rhizobacteria in the rhizosphere soil and IPs, including Bacillus, Clostridium, Sphingomonas, Paenibacillus, and Leifsonia. These low-abundance but core rhizobacteria exhibited enhanced metabolic capacities for Cd and Phen, accompanied by increased abundances of Cd-resistance genes (e.g., czcC and czcB) and Phen-degradation genes (e.g., pahE4 and pahE1) within the rhizosphere soil and IPs. Reduced planting spacing had no noticeable impact on rice biomass. These findings provide new insights into the role of low-abundance but core rhizobacterial communities in Cd and Phen uptake by rice, highlighting the potential of reduced planting spacing as an eco-friendly strategy for ensuring the safety of rice production on contaminated paddy soils.

Evaluation of succulent plants Echeveria elegans as a biomonitor of heavy metals and radionuclides

This work evaluates the use of Echeveria elegans as a biomonitor of metals and radionuclides, using semi-urban soils as a study area. The study area is exposed to various trace elements of concern for various social groups in nearby localities. The quantification of metals and radionuclides was performed by X-ray fluorescence spectrometry and gamma spectrometry, respectively. Cumulative frequency distribution curves, descriptive statistics, and multivariate analysis were used to estimate the local geochemical baseline and identify geochemical and anthropogenic patterns of metals and radionuclides from topsoil and E. elegans. The evaluation of contaminants and the contribution of possible exposure routes (topsoil and atmospheric deposition) was performed with the enrichment factor (EF) and the relative concentration factor (CFR). The results suggest that the plant does not present significant physical stress due to the environmental conditions to which it was exposed. Likewise, it can bioaccumulate heavy metals from natural and anthropogenic sources. The quantification of radionuclides in the plant is below the detection limits, indicating a low bioavailability and transfer factor. The CFR and EF results showed that the plant accumulates metals from the topsoil and atmospheric deposition. The bioaccumulation mechanism would be related to the functioning of Crassulaceae Acid Metabolism (CAM). In topsoil, the organic acids of the plant would modify the solubility of the metals present in an insoluble form in the soil, acting as ligands and, subsequently, following the transport route of these metabolites. In atmospheric deposition, the metals deposited in the leaves would be incorporated into the plant through the opening of the stomata because of the capture of CO2 (at night, day, or during environmental stress) by the CAM. Overall, the evidence showed that the succulent can be used as a biomonitor of heavy metals. However, additional studies are required to determine its usefulness as a radionuclide biomonitor.

New Light on Prions: Putative Role of PrPc in Pathophysiology of Mood Disorders.

Mood disorders are highly prevalent and heterogenous mental illnesses with devastating rates of mortality and treatment resistance. The molecular basis of those conditions involves complex interplay between genetic and environmental factors. Currently, there are no objective procedures for diagnosis, prognosis and personalization of patients' treatment. There is an urgent need to search for novel molecular targets for biomarkers in mood disorders. Cellular prion protein (PrPc) is infamous for its potential to convert its insoluble form, leading to neurodegeneration in Creutzfeldt-Jacob disease. Meanwhile, in its physiological state, PrPc presents neuroprotective features and regulates neurotransmission and synaptic plasticity. The aim of this study is to integrate the available knowledge about molecular mechanisms underlying the impact of PrPc on the pathophysiology of mood disorders. Our review indicates an important role of this protein in regulation of cognitive functions, emotions, sleep and biological rhythms, and its deficiency results in depressive-like behavior and cognitive impairment. PrPc plays a neuroprotective role against excitotoxicity, oxidative stress and inflammation, the main pathophysiological events in the course of mood disorders. Research indicates that PrPc may be a promising biomarker of cognitive decline. There is an urgent need of human studies to elucidate its potential utility in clinical practice.

Evaluation of Antibiotic Penicillin G Activities Based on Electrochemical Measurement of a Tetrazolium Salt.

This study focused on the electrochemical properties of tetrazolium salts to develop a simple method for evaluating viable bacterial counts, which are indicators of drug susceptibility. Considering that the oxidized form of tetrazolium, which has excellent cell membrane permeability, changes to the insoluble reduced form formazan inside the cell, the number of viable cells was estimated based on the reduction current of the tetrazolium remaining in the bacterial suspension. Dissolved oxygen is an important component of bacterial activity. However, it interferes with the electrochemical response of tetrazolium. We estimated the number of viable bacteria in the suspension based on potential-selective current responses that were not affected by dissolved oxygen. Based on solubility, cell membrane permeability, and characteristic electrochemical properties of the tetrazolium salt 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium, we developed a method for rapidly measuring viable bacteria within one-fifth of the time required by conventional colorimetric methods for drug susceptibility testing.

Isolation and Characterization of Phosphorus Solubilizing Bacteria from Millet Rhizosphere in Lafia metropolis

Phosphorus is an essential, but often unavailable nutrient for plant growth in the soil due to its low solubility. Phosphorus solubilizing bacteria (PSB) convert insoluble forms of phosphorus into soluble forms that can be taken up by plants. The study aimed to isolate and characterize PSB from the rhizosphere of millet plants in Lafia, and to evaluate their potential for improving soil fertility and crop productivity. Soil samples were collected from four different locations and plated on Pikovskaya's agar medium. PSB colonies were identified based on their ability to produce clear zones around them. The PSB isolates were further characterized by morphological, biochemical, and molecular methods. The phosphate solubilizing activity and plant growth-promoting traits of the PSB isolates were also assessed. The PSB isolates were tested for their effect on the growth of millet seedlings in pots. The results showed that 16 PSB isolates belonging to four genera (Bacillus, Pseudomonas, Enterobacter, and Klebsiella) were obtained from the soil samples. The PSB isolates exhibited varying degrees of phosphate solubilizing activity, ranging from 11.2 to 81.6 mg/L. The PSB isolates also showed positive results for the production of indole acetic acid, ammonia, hydrogen-cyanide, and siderophore. The PSB inoculation significantly increased the shoot and root lengths, and fresh and dry weight of the millet seedlings. The study concluded that the PSB isolates from the millet rhizosphere in Lafia could enhance soil phosphorus availability and millet growth. The study recommended further research on the field application and optimization of the PSB inoculation.

Identification of Plant Growth-Promoting Rhizobacteria for the Development of Probiotic Consortia


 Soil infertility is one of the major challenges in agriculture. Although chemical fertilizers provide promising solution for crop growth in infertile soil, excessive application cause negative impacts on the natural systems such as soil and water. Moreover, these fertilizers can be converted into insoluble forms soon after application which often result in increasing the application frequency and the quantity. Hence, for decades plant growth-promoting rhizobacteria (PGPR) have been considered as an environmentally friendly alternative for chemical fertilizers. In this context, the present study was focused on the identification of candidate PGPRs for the development of probiotic packages for chilli (Capsicum annuum L.) which is one of the most widely grown and highly demanding vegetable crops in Sri Lanka. Rhizobacteria were isolated from the roots of healthy, young chilli plants grown in Angunakolapelessa, Sri Lanka and their rhizosphere soil. In total, 75 morphologically distinct strains were isolated, and they were inoculated into different nutrient media to screen their ability to solubilize insoluble mineral nutrient sources. Those media were National-Botanical-Research-Institute's phosphate agar [NBRIP-agar] with Ca3(PO4)2 as the P source, modified-Aleksandrov-agar containing mica as the K source and zinc-solubilizing-agar containing ZnCO3 as the Zn source. Further, bacteria were screened for N fixation in the nitrogen- fixing-bacteria (NfB) medium. Sixteen P-solubilizing-bacteria (PSB), 4 K-solubilizing-bacteria (KSB), 15 Zn-solubilizing-bacteria (ZnSB) and 10 N-fixing strains were identified. We noticed that all KSB strains also have the capacity to solubilize Ca3(PO4)2. All PSB strains, except CSTM10, can solubilize ZnCO3. The phosphate solubilizing index (PSI) was calculated to rank the P-solubilizing efficiency (PSE) of PSB. The highest PSI was found in CSTM40 and CSTM6. We further screened all mineral-solubilizing strains for the indole-3-acidic acid (IAA) production which is a PGP hormone. Cultures were induced for IAA production by supplementing the medium with 0.2% (w/v) tryptophan and IAA concentration was determined using the Salkowski's method. Nine strains were capable of producing IAA. The CSTM6 and CSTM21 showed the highest IAA production of
 181.94 and 178.59 mg/L respectively. In conclusion, bacterial strains, CSTM6, CSTM14, CSTM21, CSTM24, CSTM40, CMTM1, CMTM2 and CSTM10 showed multiple PGP characteristics and they were selected as candidates for the developing probiotic consortia. They can be viewed as promising strains in sustainable agriculture since they perhaps can enhance the availability of mineral nutrients in soil and promote plant growth.
 
 Keywords: Biofertilizer, Capsicum annuum, Plant growth-promoting rhizobacteria
 
 Financial assistance from Indo-Sri Lanka Joint Research Programme 2019 funded by the State Ministry of Skill Development, Vocational Education, Research and Innovation, Sri Lanka is acknowledged.

Response of Nitrogen, Phosphorus and Potassium on Nutrient Content and Uptake by Mungbean (Vigna radiata L.)

A two-year field experiment conducted at Rama University's farm in Kanpur, Uttar Pradesh during the kharif seasons of 2022 and 2023 aimed to assess the impact of different nutrient management strategies on nutrient uptake. Phosphorus, a crucial nutrient, is deficient in insoluble forms, causing low yields in mungbean. Biofertilizers offer a cost-effective, eco-friendly, and renewable alternative to chemical fertilizers. Inoculating pulse seeds with phosphorus-solubilizing agents boosts phosphorus availability for plant growth, enhancing mungbean productivity in the Central alluvial region of Uttar Pradesh. The study incorporated four varieties—PDM-139, IPM 2-3, Meha, and IPM 2-14—alongside varying levels of nutrient management practices. These practices involved N0 (Control), N1, N2, and N3, each with distinct combinations of nitrogen, phosphorus, zinc sulfate, seed treatment with rhizobium culture, and phosphate-solubilizing bacteria (PSB). The experiment followed a factorial randomized block design with three replications. Findings indicated that the application of 20 kg N + 40 kg P2O5 + 25 kg ZnSO4.H2O ha-1, coupled with seed treatment involving rhizobium culture and PSB at 2.5 kg ha-1 in soil, significantly enhanced nutrient uptake in the Central alluvial tract of Uttar Pradesh.

Abstract B081: SOAT1 as a targetable KRAS dependency in PDAC

Abstract Metabolic rewiring is an emerging hallmark of neoplasia. In pancreatic ductal adenocarcinoma (PDAC), KRAS alters myriad metabolic programs to promote cellular transformation. Among them, the cholesterol synthesis pathway has emerged as a vulnerability of cancer cells due to the importance of cholesterol in membrane fluidity and the production of isoprenoid intermediates that enable KRAS membrane localization and activation in pancreatic cancer. We recently reported that the non-essential gene SOAT1 (Sterol-O-Acyl transferase 1), encoding an enzyme that esterifies free cholesterol into an insoluble form for storage and transport, is markedly upregulated in metastatic PDAC cells. SOAT1 promotes the hyperactivation of the mevalonate synthesis pathway due to loss of negative feedback by free cholesterol, thereby leading to increased production of isoprenoids such as farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP), which are required for RAS and RHO membrane localization and activity, respectively. Genetic ablation of Soat1 reduced RAS and RHO membrane localization and inhibited cellular proliferation and mitochondrial function in vitro, and these effects were largely rescued by exogenous FPP and GGPP. Therefore, our study nominated SOAT1 as a new candidate gene for therapeutic targeting. Based on SuFEx Click Chemistry (ASCC) technology, we have designed and synthesized a panel of drug-like candidates. The first series of Soat1 probes selectively impair the proliferation of PDAC cells that express SOAT1, reduce SOAT1 protein content in cells, and covalently bind to SOAT1. In mice, the most active SOAT1 probes were tolerated in a 28-day daily dosing study up to 120 mg/kg. Marked tumor growth inhibition was noted in mice bearing PDAC xenografts and GEMM mice treated as monotherapy with 15 mg/kg/d of the most active SOAT1 probe, and tissue analysis demonstrated tumor necrosis, decreased proliferation, and increased apoptosis. Mechanistically, SOAT1 loss or inhibition targets multiple important components of cellular transformation in PDAC including KRAS, RHO, and mitochondrial biology, and our work suggests that it is an attractive target to pursue for further drug development in this cancer. Citation Format: Wenjun Lan, Shoujun Sun, Jeremy Nigri, Josh Homer, Young Park, Astrid Deschenes, Paolo Cifani, Justin Cross, Victoria Gaeth, Sunny Kim, Shawn Ting, Rachel Rubino, John Moses, David Tuveson. SOAT1 as a targetable KRAS dependency in PDAC [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr B081.