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Applied Microbiology and Biotechnology Apr 2023The cattle tick, Rhipicephalus microplus (Acari: Ixodidae), is a multi-billion dollar ectoparasite of global importance affecting beef and milk production. Submerged...
The cattle tick, Rhipicephalus microplus (Acari: Ixodidae), is a multi-billion dollar ectoparasite of global importance affecting beef and milk production. Submerged cultures of cosmopolitan entomopathogenic fungal species of the genus Metarhizium typically produce microsclerotia that provide both long-term survival and environmental resistance. Microsclerotia hold great potential as an unconventional active propagule to control this tick under laboratory and semi-field conditions. However, heat stress caused especially by elevated temperatures poses a critical environmental constraint for the successful development and efficacy of microsclerotia under tropical conditions. First, we screened six strains of Metarhizium anisopliae, Metarhizium robertsii and Metarhizium humberi for their ability to produce microsclerotia by submerged liquid cultivation. In addition, we assessed the biological fitness and bioefficacy of dried microsclerotial pellets under amenable (27 °C) and heat-stressed (32 °C) incubation against engorged adult females of R. microplus. Microsclerotia in pelletized formulation prepared with carriers based on diatomaceous earth and microcrystalline cellulose exhibited conidial production at different extents according to the fungal strain and the incubation temperature, but most strains displayed reduced sporogenesis when exposed to 32 °C. Engorged tick females exposed to sporulated microsclerotia from pelletized M. anisopliae CG47 or IP 119 had fewer number of hatching larvae in comparison to the control group, irrespective of the incubation temperature tested. The minimum dosage of microsclerotial pellets that effectively reduced hatchability of tick larvae was estimated to be 2 mg per plate (equivalent to 6.0 kg per hectare). Metarhizium microsclerotial pellets exhibited significant tolerance to 32 °C and pronounced acaricidal activity against this economically important ectoparasite of cattle, even under simulated environmental heat stress. KEY POINTS: • Heat stress affects conidial production by microsclerotia of most pelletized Metarhizium strains • Heat stress does not impair the acaricidal performance of pelletized microsclerotia • Pellet formulation of Metarhizium microsclerotia is a promising mycoacaricide.
Topics: Animals; Female; Metarhizium; Thermotolerance; Pest Control, Biological; Rhipicephalus; Larva; Spores, Fungal
PubMed: 36929189
DOI: 10.1007/s00253-023-12467-7 -
Peer review of the pesticide risk assessment of the active substance kieselgur (diatomaceous earth).EFSA Journal. European Food Safety... Mar 2020The conclusions of EFSA following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State Austria and... (Review)
Review
The conclusions of EFSA following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State Austria and co-rapporteur Member State Greece for the pesticide active substance kieselgur (diatomaceous earth) and the considerations as regards the inclusion of the substance in Annex IV of Regulation (EC) No 396/2005 are reported. The context of the peer review was that required by Commission Implementing Regulation (EU) No 844/2012, as amended by Commission Implementing Regulation (EU) No 2018/1659. The conclusions were reached on the basis of the evaluation of the representative uses of kieselgur (diatomaceous earth) as an insecticide and acaricide on stored cereals, empty storage rooms and storage rooms, mills and warehouses (with stored goods). The reliable end points, appropriate for use in regulatory risk assessment, are presented. Missing information identified as being required by the regulatory framework is listed.
PubMed: 32874266
DOI: 10.2903/j.efsa.2020.6054 -
ACS Omega Jun 2023Immobilization of enzymes has been widely reported due to their reusability, thermal stability, better storage abilities, and so on. However, there are still problems...
Immobilization of enzymes has been widely reported due to their reusability, thermal stability, better storage abilities, and so on. However, there are still problems that immobilized enzymes do not have free movements to react to substrates during enzyme reactions and their enzyme activity becomes weak. Moreover, when only the porosity of support materials is focused, some problems such as enzyme distortion can negatively affect the enzyme activity. Being a solution to these problems, a new function "floatability" of enzyme devices has been discussed. A "floatable" micron-sized enzyme device was fabricated to enhance the free movements of immobilized enzymes. Diatom frustules, natural nanoporous biosilica, were used to attach papain enzyme molecules. The floatability of the frustules, evaluated by macroscopic and microscopic methods, was significantly better than that of four other SiO materials, such as diatomaceous earth (DE), which have been widely used to fabricate micron-sized enzyme devices. The frustules were fully suspended at 30 °C for 1 h without stirring, although they settled at room temperature. When enzyme assays were performed at room temperature, 37, and 60 °C with or without external stirring, the proposed frustule device showed the highest enzyme activity under all conditions among papain devices similarly prepared using other SiO materials. It was confirmed by the free papain experiments that the frustule device was active enough for enzyme reactions. Our data indicated that the high floatability of the reusable frustule device, and its large surface area, is effective in maximizing enzyme activity due to the high probability to react to substrates.
PubMed: 37332799
DOI: 10.1021/acsomega.3c02104 -
Materials (Basel, Switzerland) Dec 2022Portland cement porous concrete (PCPC) has received immense interest recently due to its environmental aids. Its porous structure helps to reduce the water runoff amount...
Portland cement porous concrete (PCPC) has received immense interest recently due to its environmental aids. Its porous structure helps to reduce the water runoff amount while improving the recharge of groundwater. Earlier studies have concentrated on illustrating and knowing the functional as well as structural properties of PCPC. However, very few studies are available on PCPC in combination with natural silica sources as supplementary cementitious materials (SCMs). Most SCMs are by-products of industrial manufacturing processes and cause some environmental concerns, but with their pozzolanic effect, they could be utilized as partial substitute materials for ordinary Portland cement (OPC) to enhance the strength as well as durability performance. The aim of this study is to evaluate the effects of diatomaceous earth (DE) as a supplementary cementitious material for partial substitution of OPC for Portland cement porous concrete application. Compression strength, split tensile strength, and flexural strength tests were performed to determine the effect of partial replacement. To investigate the impact of test variables, basic tests, including void content and water permeability, were also performed. Compared to the control concrete, the results show that a 15% replacement of cement with DE significantly increased the compressive strength (by 53%) while also providing adequate porosity and better water permeability. Statistical analysis (ANOVA) and regression analysis showed that there is a significant (p < 0.05) growth within the physical characteristics of concrete upon the replacement of cement by 15% DE. Collectively, the replacement of cement with DE could not only improve the concrete strength but also reduce the consumption of cement, thereby lessening the cost of construction as well as indirectly reducing the carbon footprint.
PubMed: 36614394
DOI: 10.3390/ma16010048 -
Journal of Plant Diseases and... 2023Recent outbreaks of ' Phytoplasma solani' resulted in severe losses in potatoes, vegetable crops and grapevines in certain regions of Austria and constituted a major...
UNLABELLED
Recent outbreaks of ' Phytoplasma solani' resulted in severe losses in potatoes, vegetable crops and grapevines in certain regions of Austria and constituted a major challenge for seed potato production. Therefore, the effects of various insecticides and insect deterrents on pathogen spread were studied both in laboratory and field experiments from 2018 to 2021. In laboratory transmission experiments, field captured were caged on differently treated for five days The insecticides lambda-cyhalothrin, deltamethrin, esfenvalerate, acetamiprid and chlorpyriphos showed the most rapid impact on insect survival and fully prevented phytoplasma transmission. The particle film forming products kaolin and diatomaceous earth had some effect. A transfer of the promising laboratory results to potato fields, however, was achieved to a limited extent only. Treatments with pyrethroids and acetamiprid every 8-10 days over the flight period of roughly halved the number of symptomatic plants and tubers in case of moderately susceptible varieties and moderate infection pressure. In the event of susceptible varieties and high disease pressure, treatment effects were hardy discernible. In practical terms, the experiments indicate that insecticide applications alone are not sufficient to mitigate the disease. Spraying of diatomaceous earth and mineral oil did not affect disease incidence in the field.
SUPPLEMENTARY INFORMATION
The online version contains supplementary material available at 10.1007/s41348-023-00768-y.
PubMed: 37576720
DOI: 10.1007/s41348-023-00768-y -
Environment International Feb 2023Desert dust is increasingly recognized as a major air pollutant affecting respiratory health. Since desert dust exposure cannot be regulated, the hazardousness of its...
Desert dust is increasingly recognized as a major air pollutant affecting respiratory health. Since desert dust exposure cannot be regulated, the hazardousness of its components must be understood to enable health risk mitigation strategies. Saharan dust (SD) comprises about half of the global desert dust and contains quartz, a toxic mineral dust that is known to cause severe lung diseases via oxidative stress and activation of the NLRP3 inflammasome-interleukin-1β pathway. We aimed to assess the physicochemical and microbial characteristics of SD responsible for toxic effects. Also, we studied the oxidative and pro-inflammatory potential of SD in alveolar epithelial cells and the activation of the NLRP3 inflammasome in macrophage-like cells in comparison to quartz dusts and synthetic amorphous silica (SAS). Characterization revealed that SD contained Fe, Al, trace metals, sulfate, diatomaceous earth, and endotoxin and had the capacity to generate hydroxyl radicals. We exposed A549 lung epithelial cells and wild-type and NLRP3 THP-1 macrophage-like cells to SD, three well-investigated quartz dusts, and SAS. SD induced oxidative stress in A549 cells after 24 h more potently than the quartz dusts. The quartz dusts and SAS upregulated interleukin 8 expression after 4 h and 24 h while SD only caused a transient upregulation. SD, the quartz dusts, and SAS induced interleukin-1β release from wild-type THP-1 cells>20-fold stronger than from NLRP3 THP-1 cells. Interleukin-1β release was lower for SD, in which microbial components including endotoxin were heat-destructed. In conclusion, microbial components in SD are pivotal for its toxicity. In the epithelium, the effects of SD contrasted with crystalline and amorphous silica in terms of potency and persistence. In macrophages, the strong involvement of the NLRP3 inflammasome emphasizes the acute and chronic health risks associated with desert dust exposure.
Topics: Cytokines; Dust; Endotoxins; Inflammasomes; Interleukin-1beta; NLR Family, Pyrin Domain-Containing 3 Protein; Oxidative Stress; Quartz; Silicon Dioxide; Humans; A549 Cells
PubMed: 36680803
DOI: 10.1016/j.envint.2023.107732 -
Chemosphere Jan 2023Acid mine drainage (AMD) is the term used to describe drainage from coal mines with high sulfur-bearing rocks. The oxidative weathering of metal sulfides leads to AMD....
Acid mine drainage (AMD) is the term used to describe drainage from coal mines with high sulfur-bearing rocks. The oxidative weathering of metal sulfides leads to AMD. The acidic environment corrodes more harmful compounds in the soil, which is spread throughout the working area. One such significant metal is copper, which is extracted in massive quantities from ores rich in sulfide. A copper-extraction resin might be created by combining diatomaceous earth (DE) particles with polyethyleneimine (PEI), which is shown to have great selectivity and affinity for copper. In this effort, PEI-DE particles' copper absorption level was examined by using synthetic and actual acid mine drainage samples at varied pH values. The findings of the copper uptake particles have been examined through the Support Vector Machine (SVM) model. Using the n-fold 14 cross-validation approach, the quantities of parameters and C are estimated to be 0.001 and 0.01, respectively. The SVM analysis was correct, and the findings indicated that copper could bind to the material efficiently and preferentially at pH 4. Subsequent water elution studies at a pH value of 1 confirmed the pH-reliant interaction between dissolved Cu and PEI by demonstrating full release of the adsorbed Cu. In this research, the copper absorption of PEI-DE particles from synthetic and genuine AMD specimens was studied based on several pH conditions. The findings suggest that copper may attach to the material effectively and preferentially at pH 4. Studies of filtering water at pH1 later confirmed that all of the adsorbed Cu was released. This shows that the interaction between PEI and dissolved Cu depends on PH.
Topics: Copper; Water; Metals; Mining; Water Pollutants, Chemical; Machine Learning
PubMed: 36272625
DOI: 10.1016/j.chemosphere.2022.136926 -
Food Science & Nutrition Aug 2021China has the greatest rice production in the world, but the problem of heavy metal pollution in rice is becoming increasingly serious. The present study examined a...
China has the greatest rice production in the world, but the problem of heavy metal pollution in rice is becoming increasingly serious. The present study examined a microbial immobilization method to remove cadmium (Cd) in rice flour. The study demonstrated that (. ) exhibited the best removal effect, but the microorganisms were difficult to separate from rice flour. Diatomaceous earth coimmobilized microbial pellets (DECIMPs) were prepared using coimmobilized . with sodium alginate (SA, 3%), polyvinyl alcohol (PVA, 2%), and diatomaceous earth (DE, 1%). Compared with microbial fermentation, the immobilized pellets had less influence on rice quality, and Cd removal rates of sample 1 (0.459 ± 0.006 mg/kg) and 2 (0.873 ± 0.031 mg/kg) reached 90.01% ± 1.01% (0.051 ± 0.003 mg/kg) and 91.80% ± 0.54% (0.068 ± 0.034 mg/kg), which were significantly higher than free microbial fermentation. In addition, microbial was easily separated. These results show that DECIMPs fermentation is an effective means of removing Cd from rice and could be considered as a strategy for the development of Cd-free rice-based foods.
PubMed: 34401098
DOI: 10.1002/fsn3.2427 -
Frontiers in Plant Science 2023Phytoliths are composed of 66 to 91% SiO and 1 to 6% organic carbon (C) known as phytolith occluded carbon (PhytOC). PhytOC is critical for long-term C storage in the...
Phytoliths are composed of 66 to 91% SiO and 1 to 6% organic carbon (C) known as phytolith occluded carbon (PhytOC). PhytOC is critical for long-term C storage in the agroecosystem. A field experiment was carried out to investigate the effect of three different sources of exogenous Si, i.e., diatomaceous earth (DE), silicic acid (SA) and rice husk biochar (RHB) on 1) plant phytolith, C content in phytolith and PhytOC content in different rice organs; 2) relationship between plant phytolith, C content in phytolith, PhytOC content, and soil properties (soil physicochemical properties and readily soluble silicon pools). Different Si sources produced significantly higher phytolith, PhytOC content, and readily soluble Si pools (CCSi, AASi, and ASi) than the control (RDF), with treatment receiving 4 t RHB ha outperforming the other treatments. Phytolith and PhytOC production were found to be significantly correlated to soil organic carbon (OC), available nitrogen (N) and potassium (K), 0.01 M CaCl extractable Si (CCSi) and amorphous Si (ASi) content in the soil. Redundancy analysis showed that treatments receiving 4 t RHB ha have a stronger relationship with the CCSi and ASi which majorly contributed to the higher phytolith and PhytOC production. Thus, practices such as Si fertilizers and RHB application have a high potential for phytolith production and PhytOC sequestration, a critical mechanism of the global biogeochemical C sink.
PubMed: 37692442
DOI: 10.3389/fpls.2023.1146416 -
Biotechnology Progress Mar 2022Titer improvement has driven process intensification in mAb manufacture. However, this has come with the drawback of high cell densities and associated process related...
Titer improvement has driven process intensification in mAb manufacture. However, this has come with the drawback of high cell densities and associated process related impurities such as cell debris, host cell protein (HCP), and DNA. This affects the capacity of depth filters and can lead to carryover of impurities to protein A chromatography leading to early resin fouling. New depth filter materials provide the opportunity to remove more process related impurities at this early stage in the process. Hence, there is a need to understand the mechanism of impurity removal within these filters. In this work, the secondary depth filter Millistak+ X0HC (cellulose and diatomaceous earth) is compared with the X0SP (synthetic), by examining the breakthrough of DNA and HCP. Additionally, a novel method was developed to image the location of key impurities within the depth filter structure under a confocal microscope. Flux, tested at 75, 100, and 250 LMH was found to affect the maximal throughput based on the max pressure of 30 psi, but no significant changes were seen in the HCP and DNA breakthrough. However, a drop in cell culture viability, from 87% to 37%, lead to the DNA breakthrough at 10% decreasing from 81 to 55 L/m for X0HC and from 105 to 47 L/m for X0SP. The HCP breakthrough was not affected by cell culture viability or filter type. The X0SP filter has a 30%-50% higher max throughput depending on viability, which can be explained by the confocal imaging where the debris and DNA are distributed differently in the layers of the filter pods, with more of the second tighter layer being utilized in the X0SP.
Topics: Animals; CHO Cells; Chromatography; Cricetinae; Cricetulus; Filtration; Microscopy, Confocal; Proteins
PubMed: 35037432
DOI: 10.1002/btpr.3233