Arbuscular mycorrhizal fungi activity in the rhizosphere of tree seedlings subjected to residual herbicides

Trees occurring on the margins of agricultural areas can mitigate damage from residual herbicides. Rhizospheric microbial activity associated with trees is one of the main remedial capacity indicators. The objective of this study was to evaluate the rhizospheric microbiological activity in tree species subjected to the herbicides atrazine and sulfentrazone via the rhizosphere. The experiment was designed in four blocks and a 6 × 3 factorial scheme. The first factor consisted of six tree species from Brazil and the second of atrazine, sulfentrazone, and water solutions. Four herbicide applications were performed via irrigation. The total dry mass of the plants, mycorrhizal colonization, number of spores, basal respiration of the rhizospheric soil, and survival rate of bioindicator plants after phytoremediation were determined. Trichilia hirta had higher biomass when treated with atrazine and sulfentrazone. Herbicides decreased the microbial activity in Triplaris americana and did not affect the microbiological indicators of Myrsine gardneriana, Schizolobium parahyba, and Toona ciliata. Fewer bioindicator plants survived in soil with Triplaris americana and sulfentrazone. Microbiological indicators were influenced in different ways between species by the presence of herbicides in the rhizosphere.

Chemical and microbiological changes in the soil mediated by different vegetative coverings in a Natal orange orchard

Proper soil cover management for citrus cultivation can contribute to increased productivity and improved soil quality. This study examined five different vegetative coverings [Urochloa brizantha; U. decumbens, U. ruziziensis, spontaneous vegetation, and herbicide application (glyphosate) in the total area] in the inter rows of a Natal orange orchard [Citrus sinensis (L.) Osbeck] grafted on the Swingle citrumelo (C. paradisi × Poncirus trifoliata). Their effects on the microbiological and chemical attributes of the soil and the vegetative development in the orchard were examined. Chemical (Ca2+, Mg2+, K+, P, pH, H+Al, CECpH7, base saturation, and OM) and microbiological (carbon and nitrogen of microbial biomass, basal respiration, and metabolic quotient) soil attributes in the rows and inter-rows were evaluated for the orchard in 2018 and 2019. There was a significant difference for most variables in the 2 years studied, emphasizing 2019 for microbiological parameters and OM, with the latter being 14.8% lower in the treatment with glyphosate in the total area compared to the treatment with spontaneous vegetation. The results showed the benefits of vegetation cover with brachiaria in inter-rows of the Natal sweet orange orchard in the chemical and microbiological attributes of the soil, especially in carbon and nitrogen of the microbial biomass.

SOD2 V16A Amplifies Vascular Dysfunction in Sickle Cell Patients by Curtailing Mitochondria Complex IV Activity

Superoxide dismutase 2 (SOD2) catalyzes the dismutation of superoxide to hydrogen peroxide in mitochondria limiting mitochondrial damage. The SOD2 amino acid valine-to-alanine substitution at position 16 (V16A) in the mitochondrial leader sequence is a common genetic variant among patients with sickle cell disease (SCD). However, little is known about the cardiovascular consequences of SOD2V16A in SCD patients or its impact on endothelial cell function. Here, we show SOD2V16A associates with increased tricuspid regurgitant velocity (TRV), systolic blood pressure, right ventricle area at systole and declined 6-minute walk distance in 410 SCD patients. Plasma lactate dehydrogenase, a marker of oxidative stress and hemolysis, significantly associated with higher TRV. To define the impact of SOD2V16A in the endothelium, we introduced the SOD2V16A variant into endothelial cells. SOD2V16A increases hydrogen peroxide and mitochondrial reactive oxygen species (ROS) production compared to controls. Unexpectedly, the increased ROS was not due to SOD2V16A mislocalization but was associated with mitochondrial Complex IV and a concomitant decrease in basal respiration and Complex IV activity. In sum, SOD2V16A is a novel clinical biomarker of cardiovascular dysfunction in SCD patients through its ability to decrease mitochondrial Complex IV activity and amplify ROS production in the endothelium.

First Description of the Generation of Human Schwann Cells Transfected With CRISPR Cas9 and a Model of Metformin Mitochondrial Metabolism in Metachromatic Leukodystrophy

Background: Metachromatic leukodystrophy (MLD) is a neurological lysosomal deposit disease that has an impact on public health despite its low incidence in the population. Existing treatments are expensive and inefficient. Few reports in the literature on pathophysiological events related to enzyme deficiency and subsequent accumulation of sulfatides; therefore, the use of metformin as an alternative treatment was evaluated in vitro to counteract the effects. Methodology: An experimental in vitro study that sought to determine the effect of the use of metformin on the accumulation of sulfates in glycolysis and mitochondrial function in an in vitro model of metachromatic leukodystrophy. Human Schwann cells (CSH) transfected with CRISPR Cas9 and without transfection were treated with different concentrations of sulfatides and metformin. Cell viability was evaluated by MTT and SYTOX Green; mitochondrial and glycolytic function by Seahorse XFe24, determination of reactive oxygen species (ROS) and cell death. Results: In the MTT trials, we found that treatment with different concentrations of sulfates did not affect cell viability. Transfected CSH showed higher cell death and ROS production when exposed to 100 µM sulfatides with a statistically significant difference (p <0.001), compared to nontransfected CSH cells. Sulfatides at concentrations of 10 to 100 µM affect mitochondrial bioenergetics as concentrations increase in transfected cells, in nontransfected cells they respond metabolically to exposure; Furthermore, transfected cells show a decrease in basal respiration and maximum respiration after being exposed to a concentration of 100 µM of sulphates; however, in double treatment of these cells with both sulfates and Metformin, respiration also decreases. Maximum and normal mitochondrial respiratory capacity. Conclusion: This research describes for the first time the generation of transfected CSH and the bioenergetic and mitochondrial effect of sulfates in Schwann cells, treatment with 500 µM of Metformin restores metabolic activity of these cells and decreases ROS production, as well as prevention of cell death.

Biological Indicators of Soil Condition on the Kabanyolo Experimental Field, Uganda

Soil biological activity is an integral characteristic reflecting the state of soil fertility, biodiversity, and the activity of soil processes carried out by soil organisms. In Africa, studies of soil biological properties are few compared to the agrochemical research. In this paper, we present an assessment of multiple biochemical and microbiological properties of soil from an agricultural field located in the African tropical savanna. We determined basal respiration, substrate-induced respiration, C of microbial biomass, the potential activity of denitrification, nitrogen fixation activity, and estimated prokaryotic components in the soil microbial complex by quantitative PCR. Basal respiration of soils ranged from 0.77 ± 0.04 to 1.90 ± 0.23 μg C-CO2·g−1·h−1, and substrate-induced respiration ranged from 3.31 ± 0.17 to 7.84 ± 1.04 μg C-CO2·g−1·h−1. The C reserves of microbial biomass averaged 403.7 ± 121.6 μg C·g−1 of soil. The N2O emission from the upper layer on average amounted to 2.79 ng N-N2O·g−1·day−1, and the potential denitrification activity reached 745 ± 98 ng N-N2O·g−1·h−1. The number of copies of bacterial genes varied from (0.19 ± 0.02) × 108 to (3.52 ± 0.8) × 108 copies·g−1, and of archaea—from (0.10 ± 0.01) × 107 to (0.29 ± 0.01) × 107 copies·g−1 of soil. These results were in good agreement with the studies in other seasonally wet tropical regions: the biological activity was relatively low. The difference between biological indicators of the experimental field and the reference profile were insignificant except for nitrogen loss, which was higher in the ploughed field. Biological indicators strongly varied in space; we explained their heterogeneity by non-uniform management practices in the course of agrochemical field experiments in the past. The use of organic fertilisers may cause the release of climatically active gases due to intensive microbial respiration and denitrification, but the intensity of emission would strongly depend on the cultivation and management method.

Pyruvate Kinase M1 Regulates Butyrate Metabolism in Cancerous Colonocytes

Colorectal cancer (CRC) cells shift metabolism toward aerobic glycolysis and away from using oxidative substrates such as butyrate. Pyruvate kinase M1/2 (PKM) is an enzyme that catalyzes the last step in glycolysis, which converts phosphoenolpyruvate to pyruvate. M1 and M2 are alternatively spliced isoforms of the Pkm gene. The PKM1 isoform promotes oxidative metabolism, whereas PKM2 enhances aerobic glycolysis. We hypothesize that the PKM isoforms are involved in the shift away from butyrate oxidation towards glycolysis in CRC cells. Here, we find that PKM2 is increased and PKM1 is decreased in human colorectal carcinomas as compared to non-cancerous tissue. To test whether PKM1/2 alter colonocyte metabolism, we created a knockdown of PKM2 and PKM1 in CRC cells to analyze how butyrate oxidation and glycolysis would be impacted. We report that butyrate oxidation in CRC cells is regulated by PKM1 levels, not PKM2. Decreased butyrate oxidation observed through knockdown of PKM1 and PKM2 is rescued through re-addition of PKM1. Diminished PKM1 lowered mitochondrial basal respiration and decreased mitochondrial spare capacity. We demonstrate that PKM1 suppresses glycolysis and inhibits hypoxia-inducible factor-1 alpha. These data suggest that reduced PKM1 is, in part, responsible for increased glycolysis and diminished butyrate oxidation in CRC cells.

Divergent Effects of Antibiotics on Plants and Microbiota in Soils with Contrasting Humus Content

Despite the large number of scientific studies on the effects of antibiotics on soil microorganisms, little is known about the role played by soil organic matter (humus) in the interaction of antibiotics with microorganisms and plants, including the impacts on respiration and growth rate and the implications for nitrogen metabolism, which is an important factor in soil fertility The aim of this study was to analyze the effects of two widely used antibiotics, tetracycline and streptomycin, on microbiotic activity and plant growth in two soils with dissimilar organic carbon content, at the extremes of the fertility spectrum based on humus content. The study used humus-rich (Corg 5.4%) and humus-poor soils (Corg 1.5%) and measured basal respiration, substrate-induced respiration, nitric oxide emission, germination, and growth of white mustard 3 and 60 days after three progressively increasing doses of antibiotics were applied. Tetracycline was found to impair the ecological function of humus-rich soil by reducing denitrification and compromising soil microbial activity, while the effect of streptomycin on humus-poor soil was to reduce nitrification and soil fertility due to nitrogen escape. Both streptomycin and tetracycline increased the microbial biomass and suppressed the growth of white mustard seeds, which indicates an increase in the allelopathic activity of microorganisms in the soil conditions under the influence of antibiotics and their metabolites. Due to the low sorption of streptomycin in humus-poor soils, it poses a great danger to agricultural production, especially in areas of low fertility. In humus-rich soils, high concentrations of tetracycline caused numerous problems, including death of the crop plants. Thus, the effect of antibiotics as well as the more traditional soil pollutants, such as heavy metals, to a large extent, depends on the humus content of soils.

Characterizing the Metabolic Determinants of Thromboinflammation in Myeloproliferative Neoplasms

BACKGROUND: Myeloproliferative neoplasms (MPNs) are a group of clonal hematopoietic disorders characterized by an overproduction of terminally differentiated myeloid elements. Venous and arterial thrombotic events represent the leading causes of morbidity and mortality in patients with JAK2 positive MPNs (essential thrombocythemia [ET] and polycythemia vera [PV]) in chronic phase. Platelet hyperreactivity is a hallmark finding of MPNs but the biological mechanisms remain to be elucidated. We have previously identified that platelets from patients with PV and ET exhibit dysmorphic mitochondria, however, the detailed bioenergetic and metabolomic implications of such alterations in mitochondrial mass and morphology remain to be investigated. Here in, we aim to identify the metabolic determinants that underpin thromboinflammation in patients with JAK2 positive MPNs in chronic phase. METHODS: Platelets from sex and age-matched healthy control subjects and individuals with either JAK2 positive PV or ET were isolated and washed following standard protocols. Platelet activation by flow cytometry was determined at baseline conditions. Platelet activated fibrinogen binding site (αIIbβIII), P-selectin, and phosphatidylserine (PS) surface marker expression (as measured by mean fluorescence intensity [MFI]) was determined with PAC-1 and P-selectin antibodies and lactadherin, respectively. The bioenergetic profile of washed platelets was determined by the 24-well format Seahorse extracellular flux analyzer. Metabolomic profile was developed with the Vanquish UHPLC system coupled online to a Q Exactive mass spectrometer. Statistical analyses were performed using the unpaired 2-tailed Student t test (GraphPad Software v9.1.2). Data expressed as mean plus or minus standard error of the mean (SEM). Significance was determined at p &lt; 0.05. RESULTS: Platelets from patients with MPNs had higher surface marker expression of PS under resting conditions. A trend of higher surface marker expression of αIIbβIII and P-selectin was seen (Figure 1). The platelet bioenergetic profile in individuals with MPN demonstrated decreased basal respiration (p = 0.0008), ATP-linked respiration (p = 0.001), and basal extracellular acidification rate (ECAR) (p = 0.09) (Figure 2). Liquid chromatography-mass spectrometry-based metabolomics revealed elevated pentose phosphate pathway metabolites (pentose phosphates and 6-Phospho-D-gluconate), and diminished adenosine diphosphate (ADP) and adenosine triphosphate (ATP) pools (Figure 3). CONCLUSION: The findings from this study suggest that platelets from patients with JAK2 positive PV and ET have a procoagulant phenotype given the increased expression of PS, an anionic phospholipid known to facilitate the generation of thrombin. The decreased basal respiration, ATP-linked respiration, basal ECAR (a surrogate marker of glycolysis), and energy pools (ADP and ATP) in platelets from MPN patients suggest a hypometabolic phenotype. Additionally, it appears there is preferential shunting of glucose into the pentose phosphate pathway. Such metabolic switch in conjunction with the hypometabolic state of platelets in MPN, could potentially represent a compensatory mechanism of platelets against oxidative stress. The bioenergetic dysregulation of platelets in MPNs may precipitate a cascade of events that leads to the loss of plasma membrane integrity (increased PS exposure) therefore increasing its procoagulant potential. Higher amounts of platelet PS could underly the elevated incidence of thrombosis observed in patients with JAK2 positive ET and PV. Further studies are underway to identify the inciting factor(s) that lead to the platelet bioenergetic failure and elevated PS exposure seen in patients with MPNs. These investigations will provide significant mechanistic insight for identifying therapies aimed at preventing thrombotic events in patients with MPNs. Figure 1 Figure 1. Disclosures Nemkov: Omix Thecnologies: Other: Co-founder. D'Alessandro: Omix Thecnologies: Other: Co-founder; Rubius Therapeutics: Consultancy; Forma Therapeutics: Membership on an entity's Board of Directors or advisory committees.