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Journal of Pesticide Science Aug 2022The common pistachio psylla, , is a serious global pest menacing pistachio orchards. Considering the dangers of using excessive chemical pesticides, it seems that using...
The common pistachio psylla, , is a serious global pest menacing pistachio orchards. Considering the dangers of using excessive chemical pesticides, it seems that using natural insecticides such as diatomaceous earth is a suitable way to lower the residual amount of highly hazardous pesticides. In this study, the effects of diatomaceous earth with different additives, including dipotassium hydrogen phosphate, polyurethane glue as a wood adhesive, and potassium silicate, were investigated in several concentrations over two years in orchard conditions. Although all treatments showed significant effects, the most effective treatments were (diatomaceous earth+dipotassium hydrogen phosphate) and (diatomaceous earth+polyurethane glue). Therefore, the use of diatomaceous earth combined with the additive materials mentioned can potentially be a safe method for the integrated management of the common pistachio psylla.
PubMed: 36479454
DOI: 10.1584/jpestics.D22-019 -
Polymers Aug 2022Amorphous diatomite was used as a filler for a thermoplastic polymer of polyamide 11 obtained from natural sources. The diatomite particles of different sizes were...
Amorphous diatomite was used as a filler for a thermoplastic polymer of polyamide 11 obtained from natural sources. The diatomite particles of different sizes were previously fractionated by sedimentation to obtain powders with varying particle size distribution, including powders with or without frustule particles, crushed, uncrushed or agglomerated. Biocomposites containing 2.5, 5, 10 and 20% filler were tested for their mechanical properties, including tensile strength, flexural strength and impact strength. In addition, a particle size analysis (by Dynamic Light Scattering, DLS) was performed and the dispersion of the filler in the polymer matrix (Scanning Electron Microscopy, SEM), thermal parameters (Differential Scanning Calorimetry, DSC, and Dynamic Mechanical Analysis, DMA) were determined. Testing showed that biocomposites modified with diatomaceous earth have a higher mechanical strength than the reference system, especially with larger amounts of the filler (10 and 20%), e.g., the tensile strength of pure PA11 is about 46 MPa, while 20OB and 20OF 47.5 and 47 MPa, respectively, while an increase in max. flexural strength and flexural modulus is also observed compared to pure PA11 by a maximum of 63 and 54%, respectively Diatomaceous earth can be obtained in various ways-it is commercially available or it is possible to breed diatoms in laboratory conditions, while the use of commercially available diatomite, which contains diatoms of different sizes, eliminates the possibility of controlling mechanical parameters by filling biocomposites with a filler with the desired particle size distribution, and diatom breeding is not possible on an industrial scale. Our proposed biocomposite based on fractionated diatomaceous earth using a sedimentation process addresses the current need to produce biocomposite materials from natural sources, and moreover, the nature of the process, due to its simplicity, can be successfully used on an industrial scale.
PubMed: 35956665
DOI: 10.3390/polym14153153 -
Insects Sep 2022(Schrank) (Acari: Acaridae) is a cosmopolite mite species commonly in found food and stored products. In this study, the acaricidal activity of two Turkish diatomaceous...
(Schrank) (Acari: Acaridae) is a cosmopolite mite species commonly in found food and stored products. In this study, the acaricidal activity of two Turkish diatomaceous earth (DE) formulations (Detech WP95 and Detech Dust) were applied on a concrete surface at five different concentrations (1, 2.5, 5, 7.5, and 10 g/m) and dead individuals were counted at 11 different time intervals (1, 3, 6, 9, 12, 15, 18, 21, 24, 27, and 30 h) at a temperature of 25 ± 1 °C and 75 ± 5% relative humidity (RH). Mite mortalities were observed after 6- and 18-hour exposure periods at all concentrations of dust and wettable powder (WP) formulations, respectively. Specifically, 100% mortality for the WP formulation was achieved at the highest concentration of 10 g/m after 15 h of exposure and after 27 h and 30 h for the lowest concentration. In the case of dust formulation, mortalities were observed after 3 h of exposure at all concentrations except at 1 g/m, while a 100% mortality rate was achieved after 21 h of exposure to all concentrations and after 18 h of exposure for 7.5 g/m and 10 g/m. This study indicates that both WP and dust formulations of local diatomaceous earth can cause 100% mortality in 24 h on average and can be a promising alternative to conventional chemical acaricides.
PubMed: 36292805
DOI: 10.3390/insects13100857 -
Microorganisms Jul 2023Ticks in the USA are the most important arthropod vector of microbes that cause human and animal disease. The blacklegged tick, , the focus of this study, is able to...
Ticks in the USA are the most important arthropod vector of microbes that cause human and animal disease. The blacklegged tick, , the focus of this study, is able to transmit the bacteria that causes Lyme disease in humans in the USA. The main approach to tick control is the use of chemical acaricides and repellents, but known and potential tick resistance to these chemicals requires the discovery of new methods of control. Volcanic glass, Imergard, was recently developed to mimic the insecticide mode of action of the minerals from diatoms (diatomaceous earth, DE) for the control of malaria mosquitoes in Africa. However, studies on the use of these minerals for tick control are minimal. In a dipping assay, which was put into DE (Celite), the times of 50 and 90% death of adult female were 7.3 and 10.5 h, respectively. Our mimic of DE, Imergard, killed ticks in 6.7 and 11.2 h, respectively. In a choice-mortality assay, ticks moved onto a treated surface of Imergard and died at 11.2 and 15.8 h, respectively. Ticks had greater locomotor activity before death when treated by dipping for both Imergard and Celite versus the no-mineral control. The ticks after making contact with Imergard had the mineral covering most of their body surface shown by scanning electron microscopy with evidence of Imergard inside their respiratory system. Although the assumed mode of action of Imergard and Celite is dehydration, the minerals are not hygroscopic, there was no evidence of cuticle damage, and death occurred in as little as 2 h, suggesting minimal abrasive action of the cuticle. Semi-field and field studies are needed in the future to examine the practical use of Imergard and Celite for tick control, and studies need to examine their effect on tick breathing and respiratory retention of water.
PubMed: 37630466
DOI: 10.3390/microorganisms11081906 -
Journal of Applied Microbiology Aug 2022To provide a reliable, reproducible and centrifuge-free filtration protocol for clarification of large volumes of bacterial cultures.
AIMS
To provide a reliable, reproducible and centrifuge-free filtration protocol for clarification of large volumes of bacterial cultures.
METHODS AND RESULTS
Four experiments were designed to compare different techniques enabling clarification of Escherichia coli cultures using as a benchmark the concentration and quality of bacterial outer membrane vesicles (OMVs). The experiments were designed to examine the performance of different extraction methods on large volume (≥1 L) filtrations of bacterial culture media. Performance parameters included filtration flow rates, sterility testing and characterization of the filtrates by: (i) SDS-PAGE, (ii) cryogenic transmission electron microscopy, (iii) nanoparticle tracking analysis and (iv) Qubit protein quantification. The experiments revealed that: (i) addition of the filter aid Diatomaceous Earth to the bacterial cultures improved filtration flow rates significantly and eliminated the need for centrifugation prior to filtration; (ii) sterile filtration was successful as no bacterial passage was identified through the membrane filter; (iii) centrifuge-free filtrates contained an increased amount of OMVs compared to centrifuged filtrates.
CONCLUSIONS
In comparison to conventional centrifuge-based protocols, the clarification method presented has universal applicability for a broad range of microbial extraction procedures, regardless of the volume of culture harvested. Moreover, the decreased amount of OMVs presented in the filtrates following centrifugation step provides an additional argument in favour of a centrifuge-free approach.
SIGNIFICANCE AND IMPACT OF THE STUDY
Sterile filtration is a universal method for the clarification of bacterial cultures. Common challenges related to filtration include filter clogging and long processing times, due to limited centrifugation capacity, which can affect product quality. The proposed protocol is likely to ensure a highly effective filtration process and could be a novel approach in improving the filtrate products without the need of centrifugation.
Topics: Bacteria; Centrifugation; Filtration
PubMed: 35503033
DOI: 10.1111/jam.15608 -
Insects Dec 2020was first reported in Africa in 2016 and has since become a serious threat to maize/cereal production on the continent. Current control of the pest relies on synthetic...
was first reported in Africa in 2016 and has since become a serious threat to maize/cereal production on the continent. Current control of the pest relies on synthetic chemical insecticides, which can negatively impact the environment and promote the development of resistance when used indiscriminately. Therefore, great attention is being paid to the development of safer alternatives. In this study, several biorational products and a semi-synthetic insecticide were evaluated. Two household soaps ("Palmida" and "Koto") and a detergent ("So Klin") were first tested for their efficacy against the larvae under laboratory conditions. Then, the efficacy of the most effective soap was evaluated in field conditions, along with PlantNeem (neem oil), Dezone (diatomaceous earth), and Emacot 19 EC (emamectin benzoate), in two districts, N'Dali and Adjohoun, located, respectively, in northern and southern Benin. The soaps and the detergent were highly toxic t second-instar larvae with 24 h lethal concentrations (LC) of 0.46%, 0.44%, and 0.37% for So Klin, Koto, and Palmida, respectively. In field conditions, the biorational insecticides produced similar or better control than Emacot 19 EC. However, the highest maize grain yields of 7387 and 5308 kg/ha were recorded, respectively, with Dezone (N'Dali) and Emacot 19 EC (Adjohoun). A cost-benefit analysis showed that, compared to an untreated control, profits increased by up to 90% with the biorational insecticides and 166% with Emacot 19 EC. Therefore, the use of Palmida soap at 0.5% concentration, neem oil at 4.5 L/ha, and Dezone at 7.5 kg/ha could provide an effective, environmentally friendly, and sustainable management of in maize.
PubMed: 33383724
DOI: 10.3390/insects12010018 -
Marine Drugs Aug 2023Diatom microalgae are a natural source of fossil biosilica shells, namely the diatomaceous earth (DE), abundantly available at low cost. High surface area, mesoporosity...
Diatom microalgae are a natural source of fossil biosilica shells, namely the diatomaceous earth (DE), abundantly available at low cost. High surface area, mesoporosity and biocompatibility, as well as the availability of a variety of approaches for surface chemical modification, make DE highly profitable as a nanostructured material for drug delivery applications. Despite this, the studies reported so far in the literature are generally limited to the development of biohybrid systems for drug delivery by oral or parenteral administration. Here we demonstrate the suitability of diatomaceous earth properly functionalized on the surface with -octyl chains as an efficient system for local drug delivery to skin tissues. Naproxen was selected as a non-steroidal anti-inflammatory model drug for experiments performed both in vitro by immersion of the drug-loaded DE in an artificial sweat solution and, for the first time, by trans-epidermal drug permeation through a 3D-organotypic tissue that better mimics the in vivo permeation mechanism of drugs in human skin tissues. Octyl chains were demonstrated to both favour the DE adhesion onto porcine skin tissues and to control the gradual release and the trans-epidermal permeation of Naproxen within 24 h of the beginning of experiments. The evidence of the viability of human epithelial cells after permeation of the drug released from diatomaceous earth, also confirmed the biocompatibility with human skin of both Naproxen and mesoporous biosilica from diatom microalgae, disclosing promising applications of these drug-delivery systems for therapies of skin diseases.
Topics: Humans; Animals; Swine; Diatoms; Microalgae; Naproxen; Diatomaceous Earth; Drug Delivery Systems; Anti-Inflammatory Agents, Non-Steroidal
PubMed: 37623719
DOI: 10.3390/md21080438 -
ACS Applied Materials & Interfaces Jan 2018Diatomaceous earth (DE), a nanoporous silica material composed of fossilized unicellular marine algae, possesses unique mechanical, molecular transport, optical, and...
Diatomaceous earth (DE), a nanoporous silica material composed of fossilized unicellular marine algae, possesses unique mechanical, molecular transport, optical, and photonic properties exploited across an array of biomedical applications. The utility of DE in these applications stands to be enhanced through the incorporation of nitric oxide (NO) technology shown to modulate essential physiological processes. In this work, the preparation and characterization of a biotemplated diatomaceous earth-based nitric oxide delivery scaffold are described for the first time. Three aminosilanes [(3-aminopropyl)triethoxysilane (APTES), N-(6-aminohexyl)aminomethyltriethoxysilane (AHAMTES), and 3-aminopropyldimethylethoxysilane (APDMES)] were evaluated for their ability to maximize NO loading via the covalent attachment of N-acetyl-d-penicillamine (NAP) to diatomaceous earth. The use of APTES cross-linker resulted in maximal NAP tethering to the DE surface, and NAP-DE was converted to NO-releasing S-nitroso-N-acetyl-penicillamine (SNAP)-DE by nitrosation. The total NO loading of SNAP-DE was determined by chemiluminescence to be 0.0372 ± 0.00791 μmol/mg. Retention of diatomaceous earth's unique mesoporous morphology throughout the derivatization was confirmed by scanning electron microscopy. SNAP-DE exhibited 92.95% killing efficiency against Gram-positive bacteria Staphylococcus aureus as compared to the control. The WST-8-based cytotoxicity testing showed no negative impact on mouse fibroblast cells, demonstrating the biocompatible potential of SNAP-DE. The development of NO releasing diatomaceous earth presents a unique means of delivering tunable levels of NO to materials across the fields of polymer chemistry, tissue engineering, drug delivery, and wound healing.
Topics: Animals; Diatomaceous Earth; Mice; Nitric Oxide; Porosity; Silicon Dioxide; Staphylococcus aureus
PubMed: 29278482
DOI: 10.1021/acsami.7b15967 -
Marine Drugs Apr 2023Colorectal cancer is among the most prevalent and lethal cancers globally. To address this emergency, countries have developed diffuse screening programs and innovative... (Review)
Review
Colorectal cancer is among the most prevalent and lethal cancers globally. To address this emergency, countries have developed diffuse screening programs and innovative surgical techniques with a consequent decrease in mortality rates in non-metastatic patients. However, five years after diagnosis, metastatic CRC is still characterized by less than 20% survival. Most patients with metastatic CRC cannot be surgically treated. For them, the only option is treatment with conventional chemotherapies, which cause harmful side effects in normal tissues. In this context, nanomedicine can help traditional medicine overcome its limits. Diatomite nanoparticles (DNPs) are innovative nano-based drug delivery systems derived from the powder of diatom shells. Diatomite is a porous biosilica largely found in many areas of the world and approved by the Food and Drug Administration (FDA) for pharmaceutical and animal feed formulations. Diatomite nanoparticles with a size between 300 and 400 nm were shown to be biocompatible nanocarriers capable of delivering chemotherapeutic agents against specific targets while reducing off-target effects. This review discusses the treatment of colorectal cancer with conventional methods, highlighting the drawbacks of standard medicine and exploring innovative options based on the use of diatomite-based drug delivery systems. Three targeted treatments are considered: anti-angiogenetic drugs, antimetastatic drugs, and immune checkpoint inhibitors.
Topics: Animals; Nanomedicine; Diatoms; Diatomaceous Earth; Drug Delivery Systems; Nanoparticles; Colorectal Neoplasms; Antineoplastic Agents
PubMed: 37233460
DOI: 10.3390/md21050266 -
Biomaterials Advances Jul 2024Engineering of scaffolds for bone regeneration is often inspired by the native extracellular matrix mimicking its composite fibrous structure. In the present study, we...
Engineering of scaffolds for bone regeneration is often inspired by the native extracellular matrix mimicking its composite fibrous structure. In the present study, we used low loadings of diatomite earth (DE) biosilica to improve the bone regeneration potential of gelatin electrospun fibrillar microenvironments. We explored the effect of increasing the DE content from 1 % to 3 % and 5 %, respectively, on the physico-chemical properties of the fibrous scaffolds denoted FG_DE1, FG_DE3, FG_DE5, regarding the aqueous media affinity, stability under simulated physiological conditions, morphology characteristics, and local mechanical properties at the surface. The presence of biosilica generated composite structures with lower swelling degrees and higher stiffness when compared to gelatin fibers. Increasing DE content led to higher Young modulus, while the stability of the protein matrix in PBS, at 37 °C, over 21 was significantly decreased by the presence of diatomite loadings. The best preosteoblast response was obtained for FG_DE3, with enhanced mineralization during the osteogenic differentiation when compared to the control sample without diatomite. 5 % DE in FG_DE5 proved to negatively influence cells' metabolic activity and morphology. Hence, the obtained composite microfibrillar scaffolds might find application as osteoblast-responsive materials for bone tissue engineering.
Topics: Gelatin; Osteoblasts; Tissue Scaffolds; Tissue Engineering; Animals; Diatomaceous Earth; Osteogenesis; Cell Differentiation; Mice; Bone Regeneration; Cell Line; Cellular Microenvironment; Microfibrils; Extracellular Matrix
PubMed: 38796956
DOI: 10.1016/j.bioadv.2024.213894