Acute and subchronic dermal toxicity of nanosilver in guinea pig

Silver has been used as an antimicrobial agent for a long time in different forms, but silver nanoparticles (nanosilver) have recently been recognized as potent antimicrobial agents. Although nanosilver is finding diverse medical applications such as silver-based dressings and silver-coated medical devices, its dermal and systemic toxicity via dermal use has not yet been identified. In this study, we analyzed the potential toxicity of colloidal nanosilver in acute and subchronic guinea pigs. Before toxicity assessments, the size of colloidal nanosilver was recorded in sizes <100 nm by X-ray diffraction and transmission electron microscopy. For toxicological assessments, male guinea pigs weighing 350 to 400 g were exposed to two different concentrations of nanosilver (1000 and 10,000 μg/mL) in an acute study and three concentrations of nanosilver (100, 1000, and 10,000 μg/mL) in a subchronic study. Toxic responses were assessed by clinical and histopathologic parameters. In all experimental animals the sites of exposure were scored for any type of dermal toxicity and compared with negative control and positive control groups. In autopsy studies during the acute test, no significant changes in organ weight or major macroscopic changes were detected, but dose-dependent histopathologic abnormalities were seen in skin, liver, and spleen of all test groups. In addition, experimental animals subjected to subchronic tests showed greater tissue abnormalities than the subjects of acute tests. It seems that colloidal nanosilver has the potential to provide target organ toxicities in a dose- and time-dependent manner

Determination of silver(I) by flame atomic absorption spectrometry after separation/preconcentration using modified magnetite nanoparticles

AbstractA new, simple, fast and reliable method has been developed for the separation/preconcentration of trace amounts of silver ions using 2-mercaptobenzothiazole/sodium dodecyl sulfate immobilized on alumina-coated magnetite nanoparticles (MBT/SDS-ACMNPs) and their determination by flame atomic absorption spectrometry (FAAS). Optimal experimental conditions, including pH, sample volume, eluent concentration and volume, and co-existing ions, have been studied and established. Under optimal experimental conditions, the enrichment factor, detection limit, linear range and relative standard deviation (RSD) of Ag(I) ions were 250 (for 500 mL of sample solution), 0.56 ng mL−1, 2.0–100.0 ng mL−1 and 3.1% (for 5.0 μg mL−1, n=10), respectively. The presented procedure was successfully applied for determination of silver content in the different samples of water

Comparison effects of olive leaf extract and oleuropein compounds on male reproductive function in cyclophosphamide exposed mice

Spermatogenesis is a complicated process in which sperm is susceptible to various chemotherapy drugs such as cyclophosphamide (CP). As olive leaf extract (OLE) and its active ingredient, oleuropein, have variousantioxidant, anti-apoptotic, and anti-inflammatory properties the aim of the present study was to investigate the effects of OLE and oleuropein on male reproductive function focusing antioxidative effects and histological modifications in the testes of CP-exposed mice. In order to do this, 80 NMRI male mice were divided into eight groups including control group, group received CP, group received OLE, group received oleuropein, group received OLE following CP exposure, group received oleuropein following CP exposure, group received OLE plus oleuropein and group received OLE plus oleuropein following CP exposure. In all groups CP (single dose of 100 mg/kg (, OLE (100 mg/kg for consequence 28 days) and oleuropein (100 mg/kg for consequence 28 days) were injected intraperitoneally. Moreover, testis histology, sperm parameters and serum levels of LH, FSH, MDA and antioxidant capacity were investigated. Results showed that CP caused oxidative state and abnormal changes in sperms and testes. Besides, treatments with oleuropein and OLE led to mitigate the harmful effects of CP on the male reproductive system. In conclusion, our findings showed that olive's compounds can diminish the hazardous effects of CP on spermatogenesis in mice. © 2020 The Authors Spermatogenesis; Olive leaf extract; Cyclophosphamide; Mice; Oleuropein; Cell biology; Plant biology; Pharmaceutical science; Pathophysiology; Laboratory medicine © 2020 The Author

Biotransformation of Silver Released from Nanoparticle Coated Titanium Implants Revealed in Regenerating Bone

Antimicrobial silver nanoparticle coatings have attracted interest for reducing prosthetic joint infection. However, few studies report in vivo investigations of the biotransformation of silver nanoparticles within the regenerating tissue and its impact on bone formation. We present a longitudinal investigation of the osseointegration of silver nanoparticle-coated additive manufactured titanium implants in rat tibial defects. Correlative imaging at different time points using nanoscale secondary ion mass spectrometry, transmission electron microscopy (TEM), histomorphometry, and 3D X-ray microcomputed tomography provided quantitative insight from the nano- to macroscales. The quality and quantity of newly formed bone is comparable between the uncoated and silver coated implants. The newly formed bone demonstrates a trabecular morphology with bone being located at the implant surface, and at a distance, at two weeks. Nanoscale elemental mapping of the bone−implant interface showed that silver was present primarily in the osseous tissue and colocalized with sulfur. TEM revealed silver sulfide nanoparticles in the newly regenerated bone, presenting strong evidence that the previously in vitro observed biotransformation of silver to silver sulfide occurs in vivo

Legacy genetics of Arachis cardenasii in the peanut crop shows the profound benefits of international seed exchange

A great challenge for humanity is feeding its growing population while minimizing ecosystem damage and climate change. Here, we uncover the global benefits arising from the introduction of one wild species accession to peanut-breeding programs decades ago. This work emphasizes the importance of biodiversity to crop improvement: peanut cultivars with genetics from this wild accession provided improved food security and reduced use of fungicide sprays. However, this study also highlights the perilous consequences of changes in legal frameworks and attitudes concerning biodiversity. These changes have greatly reduced the botanical collections, seed exchanges, and international collaborations which are essential for the continued diversification of crop genetics and, consequently, the long-term resilience of crops against evolving pests and pathogens and changing climate.The narrow genetics of most crops is a fundamental vulnerability to food security. This makes wild crop relatives a strategic resource of genetic diversity that can be used for crop improvement and adaptation to new agricultural challenges. Here, we uncover the contribution of one wild species accession, Arachis cardenasii GKP 10017, to the peanut crop (Arachis hypogaea) that was initiated by complex hybridizations in the 1960s and propagated by international seed exchange. However, until this study, the global scale of the dispersal of genetic contributions from this wild accession had been obscured by the multiple germplasm transfers, breeding cycles, and unrecorded genetic mixing between lineages that had occurred over the years. By genetic analysis and pedigree research, we identified A. cardenasii–enhanced, disease-resistant cultivars in Africa, Asia, Oceania, and the Americas. These cultivars provide widespread improved food security and environmental and economic benefits. This study emphasizes the importance of wild species and collaborative networks of international expertise for crop improvement. However, it also highlights the consequences of the implementation of a patchwork of restrictive national laws and sea changes in attitudes regarding germplasm that followed in the wake of the Convention on Biological Diversity. Today, the botanical collections and multiple seed exchanges which enable benefits such as those revealed by this study are drastically reduced. The research reported here underscores the vital importance of ready access to germplasm in ensuring long-term world food security.Genome sequence, genotyping, pedigree information, and yield trial data have been deposited in National Center for Biotechnology Information (NCBI), PeanutBase, and USDA Data Repository (NCBI: JADQCP000000000) (14). Datasets S1–S6 are available at USDA Ag Data Commons: https://data.nal.usda.gov/dataset/data-legacy-genetics-arachis-cardenasii-peanut-crop-v2 (17). All other study data are included in the article and/or supporting information

Gene disruption by structural mutations drives selection in US rice breeding over the last century.

The genetic basis of general plant vigor is of major interest to food producers, yet the trait is recalcitrant to genetic mapping because of the number of loci involved, their small effects, and linkage. Observations of heterosis in many crops suggests that recessive, malfunctioning versions of genes are a major cause of poor performance, yet we have little information on the mutational spectrum underlying these disruptions. To address this question, we generated a long-read assembly of a tropical japonica rice (Oryza sativa) variety, Carolina Gold, which allowed us to identify structural mutations (>50 bp) and orient them with respect to their ancestral state using the outgroup, Oryza glaberrima. Supporting prior work, we find substantial genome expansion in the sativa branch. While transposable elements (TEs) account for the largest share of size variation, the majority of events are not directly TE-mediated. Tandem duplications are the most common source of insertions and are highly enriched among 50-200bp mutations. To explore the relative impact of various mutational classes on crop fitness, we then track these structural events over the last century of US rice improvement using 101 resequenced varieties. Within this material, a pattern of temporary hybridization between medium and long-grain varieties was followed by recent divergence. During this long-term selection, structural mutations that impact gene exons have been removed at a greater rate than intronic indels and single-nucleotide mutations. These results support the use of ab initio estimates of mutational burden, based on structural data, as an orthogonal predictor in genomic selection

Proceedings of Abstracts, School of Physics, Engineering and Computer Science Research Conference 2022

© 2022 The Author(s). This is an open-access work distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. For further details please see https://creativecommons.org/licenses/by/4.0/. Plenary by Prof. Timothy Foat, ‘Indoor dispersion at Dstl and its recent application to COVID-19 transmission’ is © Crown copyright (2022), Dstl. This material is licensed under the terms of the Open Government Licence except where otherwise stated. To view this licence, visit http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3 or write to the Information Policy Team, The National Archives, Kew, London TW9 4DU, or email: [email protected] present proceedings record the abstracts submitted and accepted for presentation at SPECS 2022, the second edition of the School of Physics, Engineering and Computer Science Research Conference that took place online, the 12th April 2022