Exploring the antibiofilm and toxicity of tin oxide nanoparticles: Insights from in vitro and in vivo investigations

BACKGROUND INFORMATION

The advancement of biological-mediated nanoscience towards higher levels and novel benchmarks is readily apparent, owing to the use of non-toxic synthesis processes and the incorporation of various additional benefits. This study aimed to synthesize stable tin oxide nanoparticles (SnO2-NPs) using S. rhizophila as a mediator.

METHODS

The nanoparticles that were created by biosynthesis was examined using several analytical techniques, including Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), X-ray diffraction (XRD), UV-visible (UV-vis) spectroscopy, and energy dispersive X-ray spectroscopy (EDS).

RESULTS

The results obtained from the characterization techniques suggest that S. rhizophila effectively catalyzed the reduction of SnCl2 to SnO2-NPs duration of 90 min at ambient temperature with the ƛmax of 328 nm. The size of the nano crystallite formations was measured to be 23 nm. The present study investigates nanoscale applications' antibacterial efficacy against four bacterial strains, including Klebsiella Sp, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. The observed zone of inhibition for the nanoparticles (NPs) varied from 10 to 25 mm. The research findings demonstrate that the nanoparticles (NPs) are effective as antibacterial, phytotoxic, and cytotoxic agents.

Layered structure of sialoliths compared with tonsilloliths and antroliths

Objectives

The aim of this study was to perform a comparative analysis of the ultrastructural and chemical composition of sialoliths, tonsilloliths, and antroliths and to describe their growth pattern.

Materials and Methods

We obtained 19 specimens from 18 patients and classified the specimens into three groups: sialolith (A), tonsillolith (B), and antrolith (C). The peripheral, middle, and core regions of the specimens were examined in detail by histology, micro-computed tomography (micro- CT), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy, and transmission electron microscopy (TEM).

Results

In the micro-CT, group A showed alternating radiodense and radiolucent layers, while group B had a homogeneous structure. Group C specimens revealed a compact homogeneous structure. Histopathologically, group A showed a laminated, teardrop-shaped, globular structure. Group B demonstrated degrees of immature calcification of organic and inorganic materials. In group C, the lesion was not encapsulated and showed a homogeneous lamellar bone structure. SEM revealed that group A showed distinct three layers: a peripheral multilayer zone, intermediate compact zone, and the central nidus area; groups B and C did not show these layers. The main elemental components of sialoliths were O, C, Ca, N, Cu, P, Zn, Si, Zr, F, Na, and Mg. In group B, a small amount of Fe was found in the peripheral region. Group C had a shorter component list: Ca, C, O, P, F, N, Si, Na, and Mg. TEM analysis of group A showed globular structures undergoing intra-vesicular calcification. In group B, bacteria were present in the middle layer. In the outer layer of the group C antrolith, an osteoblastic rimming was observed.

Conclusion

Sialoliths had distinct three layers: a peripheral multilayer zone, an intermediate compact zone and the central nidus area, while the tonsillolith and antrolith specimens lacked distinct layers and a core.

Chemical and spectroscopic characterization of (Artemisinin/Querctin/ Zinc) novel mixed ligand complex with assessment of its potent high antiviral activity against SARS-CoV-2 and antioxidant capacity against toxicity induced by acrylamide in male rats

A novel Artemisinin/Quercetin/Zinc (Art/Q/Zn) mixed ligand complex was synthesized, tested for its antiviral activity against coronavirus (SARS-CoV-2), and investigated for its effect against toxicity and oxidative stress induced by acrylamide (Acy), which develops upon cooking starchy foods at high temperatures. The synthesized complex was chemically characterized by performing elemental analysis, conductance measurements, FT-IR, UV, magnetic measurements, and XRD. The morphological surface of the complex Art/Q/Zn was investigated using scanning and transmission electron microscopy (SEM and TEM) and energy dispersive X-ray analysis (XRD). The in vitro antiviral activity of the complex Art/Q/Zn against SARS-CoV-2 and its in vivo activity against Acy-induced toxicity in hepatic and pulmonary tissues were analyzed. An experimental model was used to evaluate the beneficial effects of the novel Art/Q/Zn novel complex on lung and liver toxicities of Acy. Forty male rats were randomly divided into four groups: control, Acy (500 mg/Kg), Art/Q/Zn (30 mg/kg), and a combination of Acy and Art/Q/Zn. The complex was orally administered for 30 days. Hepatic function and inflammation marker (CRP), tumor necrosis factor, interleukin-6 (IL-6), antioxidant enzyme (CAT, SOD, and GPx), marker of oxidative stress (MDA), and blood pressure levels were investigated. Histological and ultrastructure alterations and caspase-3 variations (immunological marker) were also investigated. FT-IR spectra revealed that Zn (II) is able to chelate through C=O and C-OH (Ring II) which are the carbonyl oxygen atoms of the quercetin ligand and carbonyl oxygen atom C=O of the Art ligand, forming Art/Q/Zn complex with the chemical formula [Zn(Q)(Art)(Cl)(H2O)2]⋅3H2O. The novel complex exhibited a potent anti-SARS-CoV-2 activity even at a low concentration (IC50 = 10.14 µg/ml) and was not cytotoxic to the cellular host (CC50 = 208.5 µg/ml). Art/Q/Zn may inhibit the viral replication and binding to the angiotensin-converting enzyme-2 (ACE2) receptor and the main protease inhibitor (MPro), thereby inhibiting the activity of SARS-CoV-2 and this proved by the molecular dynamics simulation. It alleviated Acy hepatic and pulmonary toxicity by improving all biochemical markers. Therefore, it can be concluded that the novel formula Art/Q/Zn complex is an effective antioxidant agent against the oxidative stress series, and it has high inhibitory effect against SARS-CoV-2.

Buckling and fracture characterization of pristine bundles of vertically aligned carbon nanotubes using quantitative in situ TEM axial compression

This work investigates the mechanical deformation and fracture characteristics of pristine bundles of vertically aligned Multi-Walled Carbon Nanotubes (MWCNT) subjected to axial compression in situ Transmission Electron Microscope (TEM). Accurate measurements of force-displacement data were collected simultaneously with real-time TEM videos of the deformation process. Two distinct regimes were observed in the force-displacement curve: (1) an initial elastic section with a linear slope, followed by (2) a transition to a force plateau at a critical buckling force. Morphological data revealed coordinated buckling of the pristine bundle, indicating strong van der Waals (VdW) forces between the nanotubes. The experimental setup measured an effective modulus of 83.9 GPa for an MWCNT bundle, which was in agreement with finite element analysis (FEA) simulations. FEA also highlighted the significant role of VdW forces in the bundle mechanical reactions. Furthermore, we identified nickel nanoparticles as key players in the fracture behavior of the bundles, acting as nucleation sites for defects. The direct mechanical measurements of MWCNT bundles provide valuable insights into their mechanical deformation and fracture behavior, while correlating it to the morphology of the bundle. Understanding these interactions at the bundle level is crucial for improving the reliability and durability of VACNTs-based components.

Antibacterial and anti-corona virus (229E) activity of Nigella sativa oil combined with photodynamic therapy based on methylene blue in wound infection: in vitro and in vivo study

Microbial skin infections, antibiotic resistance, and poor wound healing are major problems, and new treatments are needed. Our study targeted solving this problem with Nigella sativa (NS) oil and photodynamic therapy based on methylene blue (MB-PDT). Antibacterial activity and minimum inhibitory concentration (MIC) were determined via agar well diffusion assay and broth microdilution, respectively. Transmission electron microscopy (TEM) proved deformations in Staphylococcus aureus ATCC 6538. Gas chromatography-mass spectrometry identified useful compounds that were suggested to be responsible for the potency of the oil. NS oil was tested as an antivirus against low pathogenic coronavirus (229E). Therapies examined, MB-PDT, NS, and MB-PDT + NS oil, to accelerate wound healing. The antibacterial efficacy against S. aureus was promising, with a MIC of 12.5% and TEM showing injured cells treated with NS oil. This oil inhibited 229E virus up to 42.85% and 32.14%. All tested therapies were successful in accelerating wound healing. The most successful was combined therapy (MB-PDT + NS oil), with a faster healing time. The combined therapy (MB-PDT + NS oil) reduced bacterial counts, which may be a key factor in accelerating wound healing. Skin wound histology was investigated; blood hematology and biochemical analysis did not change significantly after the safe combination treatment. A combination treatment could facilitate healing in a simple and inexpensive way in the future. Based on the results of the in vitro and in vivo studies, it was determined that NS oil had antibacterial and anti-corona virus activity when used in conjunction with photodynamic treatment based on methylene blue to treat wound infections.

A correction for higher-order refraction in cathodoluminescence spectrometry

Cathodoluminescence (CL) is a developing analytical method in electron microscopy, because of its excellent energy resolution. Usually a Czerny-Turner type spectrometer is employed, having a blazed grating as analyzer. Unlike a prism analyzer, where the dispersion depends on the refractive index of the prism itself leading to a non-linear spectral distribution, the grating has the advantage that the spectral distribution depends linearly on the wavelength. As a draw-back, higher-order refraction alters the measured optical spectrum at larger wavelengths. In general, blazed gratings are used in order to minimize this effect in a certain spectral range. Nevertheless, the higher-order intensities can be still significant. In the present study we present a method for correcting the acquired optical spectra with respect to higher order diffraction intensities and apply it to CaO and GaN CL-spectra.

Detection of Ferroptosis in Patient-Derived Tumor Models

Ferroptosis is a form of iron-dependent regulated cell death that is primarily caused by the accumulation of iron, lipid peroxidation, and subsequent rupture of the plasma membrane. The process and function of ferroptosis can be monitored in multiple ways, both in vitro and in vivo. Patient-derived xenograft (PDX) is a type of preclinical cancer model that involves transplanting human cancer tissue, usually obtained from patients undergoing surgery or biopsy, into immunodeficient mice or other animal models. It is a powerful tool for understanding drug response in cancer, as PDX models preserve the growth environment and heterogeneity of the original tumors. By analyzing ferroptosis in PDX models, we can potentially gain insights into human tumorigenesis. In this article, we summarize several assays used to analyze ferroptosis in PDX models.

High-quality, large-scale, semi-thin, & ultra-thin sections of the optic nerve in large animals: An optimized procedure

Large animal model of optic nerve (ON) injury is an essential tool for translational medicine. Perfusion fixation with paraformaldehyde is mainly used for preparing the semi-thin (1-2 μm thick) and ultra-thin (<0.5 μm thick) sections of the ON tissues. However, this conventional fixation technique in large animals needs a large volume of fixatives, which increases the risk of toxic exposure and is environmentally unfriendly. Additionally, fixed residual ON cannot be used for other tests that require fresh tissue samples. Although conventional immersion fixation is feasible for preparing a semi-thin section of the ON in small animals (0.2-0.6 mm in diameter), it faces technical challenges when fixing the ON of large animals (3 mm in diameters), as increased diameter limits the permeability of the fixatives into deeper tissue. Therefore, we optimized the immersion-fixation method to obtain high-quality, large-scale, semi-thin, and ultra-thin sections for the ON of goat and rhesus macaques. Using this optimized technique, the ON microstructure was well preserved throughout the entire area of 1.5*1.5 square millimeters, allowing confident quantification of axon density/diameter on semi-thin section and identification of specific organelles and glial cells on ultra-thin sections. Furthermore, the optimized technique is a quick, simple, and environmentally friendly fixation method. Notably, the ON regions of large animals with or without an intact neurovascular system can be prepared for light and electron microscopy. In contrast, the residual unfixed ON from the same animal can be further utilized for experiments such as tissue culture and biomolecular tests.

Oxidative Stress and Toxico-Pathic Branchial Lesions in Cyprinus carpio Exposed to Malachite Green

Gill is the frontier tissue to come in direct contact with aquatic toxicants. Malachite green (MG) commercial textile dye was assessed for its impact on the gill cytoarchitecture. Cyprinus carpio were exposed to 0.087 and 0.146 mg/L of MG for 60 days. The tissue was processed, and HE stained slides revealed histo-pathic lesions such as lamellar curling, edema, necrosis, telangiectasia, aneurysm, and vacuolization. Scanning electron microscopy reported aberrations in lamellae and microridges of the epithelium. At the cellular level, transmission electron microscopy exhibited nuclear alterations in form of pyknosis and mitochondrial swelling followed by cristolysis. Pillar cells displayed cytoplasmic vacuolization and leukocyte infiltration, and goblet cell containing varied shaped and density mucous globules. The biochemical analysis supported the ultrastructural alterations and showed a negative impact of MG on the antioxidative enzymes (CAT, SOD, GSH), while levels of MDA were found to be significantly elevated. Thereby, concluding MG induced branchial toxicity in the fish.

Ultrastructure characteristics of primordial germ cells in stage X of pheasant (Phasianus colchicus) embryo

Stage X is one of the formation stages in birds at which the blastoderm area is distinguished by two areas of area pellucida being responsible for formation of embryonic tissues and primordial germ cells, and area opaca forming the extra-embryonic tissues. Primordial germ cells are multi-potent stem cells giving rise to spermatogonia or oogonia. The present study was carried out to describe the characteristics of primordial germ cells in stage X of pheasants' embryo using a transmission electron microscope. The blastoderm was dissected out from embryos which were already incubated for 12 hr. Toluidine blue was used for staining semi-thin sections; lead citrate and uranyl acetate were also used to stain ultra-thin sections. Images of primordial germ cells elucidated that the nucleus was situated eccentrically and had a compact spherical structure. Moreover, the nucleolus appeared elongated and was located eccentrically. The cytoplasm was composed of yolk granules and glycogen particles. Mitochondria were observed as round structures in the cytoplasm. The most important finding was that the primordial germ cells contained yolk granules, mitochondria and small amount of glycogen at this stage.

Green synthesis of silver nanoparticles with algae and the importance of capping agents in the process

BACKGROUND

Nanoparticle synthesis is a very interesting area of research currently due to the wide applications of nanoparticles. The nanoparticles have a diameter ranging between 1 and 100 nm and they are used in different fields like electronics, pharmaceuticals, cosmetics, biotechnology, medicines, etc. Nanoparticles have gained the interest of researchers due to their large surface-to-volume ratio and their capability to interact effectively with other particles. Several different methods can be used for the production of silver nanoparticles (AgNPs) including chemical, physical, and biological. Out of all the methods, the biological method is considered the cleanest and safest as no toxic chemicals are used in the process. The biological method includes the use of bacteria, fungi, algae, and plant extract for the synthesis. Algal synthesis of AgNPs is especially interesting because of the high capacity of the algae to take in metals and reduce metal ions. Algae is a widely distributed organism and its availability is abundant; an added advantage is their growth under laboratory conditions. These organisms can help in large-scale production at a low cost.

SHORT CONCLUSION

This review article explains the different factors that should be considered for the effective synthesis of AgNPs using algae. Capping agents also affect the stability of nanoparticles. It also sheds light on the importance of capping agents in the synthesis of AgNPs. Alga-mediated synthesis of AgNPs along with the use of different capping agents can help in modulating the stability and size of the nanoparticles, thereby improving its cost-effectiveness and environment-friendly production.

Ultramicrotomy preparation of magnetic nanoparticles for transmission electron microscopy

Transmission electron microscopy (TEM) is one of the most important methods for the morphological characterization and structure analysis of nanomaterials. However, the characterization of magnetic materials has always been a challenge due to limitations arising from the design of electron microscopes. To tackle this problem, advanced sample preparation technology is needed, especially for magnetic materials. Here in this work ultrathin sectioning technology (ultramicrotomy) is used for the sample preparation of magnetic Fe₃O₄ nanoparticles embedded into a resin, where the loaded resin can be sliced into nanoscale sheets. By the optimization of the embedding method and the slicing process, nano-sheets with uniform thickness and exceptional flatness were prepared, where the nanoparticles exhibited uniform dispersion. It is shown that this technology also helps reducing the degree of pollution of the electron microscope by the magnetic nanoparticles under different electron beam irradiation intensities. Generally, the magnetic nanoparticles are more resistant to electron beam bombardment when embedded into a resin.

Inhibitory mechanism of an antifungal drug, caspofungin against amyloid β peptide aggregation: Repurposing via neuroinformatics and an experimental approach

The multifactorial neurological condition called Alzheimer's disease (AD) primarily affects elderly individuals. Despite the calamitous consequences of AD, curative strategies for a regimen to apply remain inadequate as several factors contribute to AD etiology. Drug repurposing is an advance strategy prior to drug discovery as various effective drugs perform through alteration of multiple targets, and the present "poly-pharmacology" can be a curative approach to complex disorders. AD's multifactorial behavior actively encourages the hypothesis for a drug design approach focused on drug repurposing. In this study, we discovered that an antifungal drug, Caspofungin (CAS) is a potent Aβ aggregation inhibitor that displays significantly reduced toxicity associated with AD. Drug reprofiling and REMD simulations demonstrated that CAS interacts with the β-sheet section, known as Aβ amyloid fibrils hotspot. CAS leads to destabilization of β-sheet and, conclusively, in its devaluation. Later, in vitro experiments were acquired in which the fibrillar volume was reduced for CAS-treated Aβ peptide. For the first time ever, this study has determined an antifungal agent as the Aβ amyloid aggregation's potent inhibitor. Several efficient sequence-reliant potent inhibitors can be developed in future against the amyloid aggregation for different amyloid peptide by the processing and conformational optimization of CAS.

[Improvement in platelet count and bleeding symptom during treatment with eltrombopag in a patient with X-linked thrombocytopenia]

Herein, we describe a 13-year-old male adolescent who had chronic thrombocytopenia since infancy. In this case, X-linked thrombocytopenia (XLT) was suspected owing to a family history of chronic thrombocytopenia and small-sized platelets. Moreover, the patient was refractory to immunoglobulin therapy. The Wiskott-Aldrich syndrome protein (WASP) expression analysis revealed a decreased expression. Results showed a missense mutation [c.296A>G (p.Gln99Arg)] in exon 3 of the WASP-interacting protein region. Therefore, a diagnosis of XLT was made. To lift exercise restrictions, we initiated treatment with eltrombopag at a dose of 12.5 µg/day. The platelet count of the patient increased to approximately 50×10³/µl after the treatment dose was escalated to 25 µg/day, and bleeding symptoms decreased after the patient resumed exercise. Ultrastructural platelet abnormalities and abnormal platelet aggregation were observed on transmission electron microscopy after the administration of eltrombopag. Therefore, eltrombopag treatment can increase platelet count and reduce bleeding symptoms in patients with XLT.

Synergistically-acting Enterocin LD3 and Plantaricin LD4 Against Gram-Positive and Gram-Negative Pathogenic Bacteria

The efficacy of antimicrobials is an important aspect during their applications in food and therapeutics. In this study, combination of two bacteriocins, enterocin LD3 and plantaricin LD4, was studied against two pathogenic bacteria, Staphylococcus aureus subsp. aureus ATCC25923 and Salmonella enterica subsp. enterica serovar Typhimurium ATCC13311 for increasing their potency and bactericidal activity. The minimal inhibitory concentrations (MICs) of enterocin LD3 and plantaricin LD4 against Staph. aureus subsp. aureus ATCC25923 were 180 and 220 μg/mL, whereas in combination, reduced to 115 μg/mL, respectively. The MICs of enterocin LD3 and plantaricin LD4 against Salm. enterica subsp. enterica serovar Typhimurium ATCC13311 were 240 and 320 μg/mL, respectively, whereas in combination, these were found to be 130 μg/mL, respectively. The fractional inhibitory concentration (FIC) indices calculated as 0.50 against Staph. aureus subsp. aureus ATCC25923 and 0.43 against Salm. enterica subsp. enterica serovar Typhimurium ATCC13311 were found to be ≤ 0.5 indicating the synergy. The isobologram showed MIC of combined bacteriocins falls below the plotted straight line further signifies synergy. The growth response of Staph. aureus subsp. aureus ATCC25923 and Salm. enterica subsp. enterica serovar Typhimurium ATCC13311 was significantly reduced in the presence of combined bacteriocins in comparison with their individual effects. The number of dead cells was higher as a result of combined effect as compared with their independent effect evidenced by fluorescent microscopy. Transmission electron microscopy (TEM) revealed the higher disruption of cell membrane in the combined bacteriocin-treated cells as compared with alone effects. The FTIR spectra of enterocin LD3-treated cells showed alteration at ~ 1,451.82 and ~ 1,094.30/cm corresponding to nucleic acids and phospholipids suggesting its interaction with cell membrane and nucleic acids. In contrast, plantaricin LD4-treated cells did not show such alterations suggesting plantaricin LD4 may kill target cells using other mechanism. Our data suggest that different mode of action of both bacteriocins results in division of labour and may be responsible for their synergistic activity against target cells. Similarly, the synergistic effect of bacteriocins was also observed against other pathogenic bacteria such as Proteus mirabilis ATCC43071, Pseudomonas aeruginosa ATCC27853 and Escherichia coli ATCC25922. These bacteriocins, therefore, act synergistically against target pathogens and may be applied in appropriate combinations for food safety and medical applications.

Orientation mapping with Kikuchi patterns generated from a focused STEM probe and indexing with commercially available EDAX software

Relating a crystal's microscopic structure-such as orientation and size-to a material's macroscopic properties is of great importance in materials science. Although most crystal orientation microscopy is performed in the scanning electron microscope (SEM), transmission electron microscopy (TEM)-based methods have a number of benefits, including higher spatial resolution. Current TEM orientation methods have either specific hardware requirements or use software that has limited scope, utility, or availability. In this article, a technique is described for orientation mapping using Kikuchi diffraction patterns generated from a focused STEM probe. One key advantage is that indexing and analysis of the patterns and maps occurs in the robust OIM Analysis software, currently widely used for electron backscatter diffraction (EBSD) and transmission Kikuchi diffraction (TKD) analysis. It was found that with minimal to no image processing and by changing only a few software parameters, reliable indexing of Kikuchi patterns is possible. Three samples, a deformed β-Titanium (Ti), a medium carbon heat-treated steel, and BaCe_0.8Y_0.2O_3-δ were tested to determine the effectiveness of the approach. In all three measurements the algorithms effectively and reliably determined the phases and the crystal orientations of the features measured. For the two orientation maps produced, less than 5% of the patterns were misindexed including boundary areas where overlapping patterns existed. An angular resolution of 0.15° was achieved while features <25 nm were able to be spatially resolved.

Toxic responses of metabolites, organelles and gut microorganisms of Eisenia fetida in a soil with chromium contamination

The toxic sensitivity in different physiological levels of chromium (Cr) contaminated soils with environmentally equivalent concentrations (EEC) was fully unknown. The earthworm Eisenia fetida was exposed to a Cr-contaminated soil at the EEC level (referred to as Cr-CS) to characterize the induced toxicity at the whole body, organ, tissue, subcellular structure and metabolic levels. The results showed that the survival rate, weight and biodiversity of the gut microorganisms (organ) had no significant difference (p > 0.05) between control and Cr-CS groups. Qualitative histopathological and subcellular evaluations from morphology showed earthworms obvious injuries. The organelle injuries combined with the metabolic changes provided additional evidence that the Cr-CS damaged the nucleus and probably disturbed the nucleic acid metabolism of earthworms. 2-hexyl-5-ethyl-3-furansulfonate, dimethylglycine, betaine and scyllo-inositol were sensitive and relatively quantitative metabolites that were recommended as potential biomarkers for Cr-CS based on their significant weights in the multivariate analysis model. In addition, the relative abundance of Burkholderiaceae, Enterobacteriaceae and Microscillaceae of the earthworm guts in the Cr-CS group significantly increased, particularly for Burkholderiaceae (increased by 13.1%), while that of Aeromonadaceae significantly decreased by 5.6% in contrast with the control group. These results provided new insights into our understanding of the toxic effects of the EEC level of Cr contaminated soil from different physiological levels of earthworms and extend our knowledge on the composition and sensitivity of the earthworm gut microbiota in Cr contaminated soil ecosystems. Furthermore, these toxic responses from gut microorganisms to metabolites of earthworms provided important data to improve the adverse outcome pathway and toxic mechanism of the Cr-CS if the earthworm genomics and proteomics would be also gained in the future.

Effect of acute gold nanorods on reproductive function in male albino rats: histological, morphometric, hormonal, and redox balance parameters

In this study, we investigated the effect of acute administration of gold nanorods (AuNRs) on testicular function, sexual hormones, and oxidative stress parameters in male albino rats. Forty mature male albino rats were divided into two equal groups (n = 20/each). The first group received 1 ml saline solution intraperitoneally (i.p.). The second group received single i.p. injection of 75 μg 50 nm AuNRs/kg/bwt. Five rats from each group were sacrificed on days 1, 3, 7, and 14 post treatment and blood samples were collected for hormonal and biochemical analysis. Testes were collected from each group at each time point for histopathology, morphometric, and transmission electron microscope analyses of testis and epididymis. Results indicated that i.p. injection of AuNRs did not produce any histopathological changes. Morphometric analysis of testicular samples revealed that the height of lining epithelium was significantly (P < 0.05) higher in AuNR group on days 3 and 14 post treatment, and the minor axis of seminiferous tubules was higher (P < 0.05) in AuNR-injected rats than in control group. For the epididymis, the number of spermatozoa was significantly (P < 0.05) higher on days 7 and 14 after AuNR injection when compared with control rats. AuNRs were not detected by TEM at all time points of the experiment. Serum analysis demonstrated that total and free testosterone values significantly (P < 0.05) increased on days 1, 3, 7, and 14 post AuNR injection. LH was higher (P < 0.05) in AuNRs-injected rats on days 3, 7, and 14 post injection, while FSH values were higher (P < 0.05) in AuNR group on days 3 and 14. Malondialdehyde significantly (P < 0.05) decreased on days 3, 7, and 14 in AuNR group, while catalase, glutathione peroxidase, and superoxide dismutase values were significantly (P < 0.05) elevated on days 3, 7, and 14 in AuNRs-injected rats compared with control group. In conclusion, intraperitoneal injection of 50 nm AuNRs is safe on the reproductive function and has an antioxidant action.

Antioxidant, antiapoptotic, antigenotoxic, and hepatic ameliorative effects of L-carnitine and selenium on cadmium-induced hepatotoxicity and alterations in liver cell structure in male mice

L-carnitine (LC) and selenium (Se) have significant protective and antioxidant effects on several tissues. Cadmium (Cd), widely used in some industries and emitted from fossil fuels, is a heavy metal having a number of side effects, including hepatotoxicity. This study aims to assess the ameliorative function of both LC and SeCl₄ on cadmium chloride (CdCl₂)-induced liver toxicity. In total, 70 male mice included in this study were allocated to seven groups: control, CdCl₂, LC, SeCl₄, CdCl₂ plus SeCl₄, CdCl₂ plus LC, CdCl₂ plus SeCl₄ and LC groups. Hepatic aminotransferase (aspartate aminotransferase [AST] and alanine transaminase [ALT]) activity and tumor necrosis factor-alpha [TNF-α] levels, as well as the antioxidant biomarkers (superoxide dismutase [SOD], glutathione reductase [GRx], glutathione-S-transferase [GST] and catalase [CAT], were examined. Histological and transmission electron microscopic [TEM] variations in the liver were used as indicators of liver damage after the administration of CdCl₂-alone or CdCl₂ with LC, SeCl₄, or both. Genotoxic effects of CdCl₂ were also evaluated and the possible roles of SeCl₄ and/or LC on the expression of the antioxidant enzymes were studied. Results showed that administration of LC and SeCl₄ decreased CdCl₂-induced increase in ALT and AST levels and reduced oxidative stress to normal levels. In addition, LC combined with SeCl₄ had a highly synergistic effect and elevated significantly the enzymatic antioxidants and decreased lipid peroxidation levels compared with those in the CdCl₂-treated group. It is clear from the data that both LC and SeCl₄ inhibit liver injury and improve the redox state in mice.

A field study on the possible attachment of DPM and respirable dust in mining environments

Typcial monitoring procedures for diesel particulate matter (DPM) in mines include the collection of filter samples using particle size selectors. The size selectors are meant to separate the DPM, which is generally considered to occur in the submicron range (i.e., < 0.8 μm), from larger dust particles that could present analytical interferences. However, previous studies have demonstrated that this approach can sometimes result in undersampling, therefore, excluding significant fractions of the DPM mass. The excluded fraction may represent oversized DPM particles, but another possibility is that submicron DPM attaches to supramicron dust particles such that it is effectively oversized. To gain insights into this possibility, a field study was conducted in an underground stone mine. Submicron, respirable, and total airborne particulate filter samples were collected in three locations to determine elemental carbon (EC) and total carbon (TC), which are commonly used as analytical surrogates for DPM. Concurrent with the collection of the filter samples, a low-flow sampler with an electrostatic precipitator was also used to collect airborne particulates onto 400-mesh copper grids for analysis by transmission electron microscope (TEM). Results indicated that, while typical submicron sampling did account for the majority of DPM mass in the study mine, DPM-dust attachment can indeed occur. The effect of exposure to such attached particulates has not been widely investigated.

Inhibition of microRNA-103a inhibits the activation of astrocytes in hippocampus tissues and improves the pathological injury of neurons of epilepsy rats by regulating BDNF

Background

The aim of this study is to explore the effect of microRNA-103a (miR-103a) on astrocytes activation and hippocampal neuron injury in epilepsy rats by targeting brain-derived neurotrophic factor (BDNF).

Methods

The epilepsy rat model was induced by intraperitoneal injection of lithium chloride-pilocarpine. Successful modeled rats were intralateroventricularly microinjected with miR-103a inhibitors, inhibitors negative control (NC), siRNA-NC and BDNF-siRNA, respectively. The RT-qPCR and western blot analysis were used to detect the expression of miR-103a, BDNF and glial fibrillary acidic protein (GFAP) in hippocampus tissues of rats. TUNEL staining was used to detect the apoptosis of hippocampal neurons. The RT-PCR and ELISA was used to detect the levels of TNF-α and IL-6 in hippocampal tissues and in serum, respectively.

Results

Increased expression of miR-103a, GFAP, and number of apoptotic neurons, decreased expression of BDNF and number of surviving neurons were found in hippocampus tissues of epilepsy rats. After miR-103a inhibitors interfered with epilepsy rats, there showed decreased expression of miR-103a and GFAP, increased expression of BDNF and decreased number of apoptotic neuron as well as increased number of surviving neurons. Compared with miR-103a inhibitors alone, epilepsy rats treated with BDNF-siRNA combined with miR-103a inhibitors significantly increased expression of GFAP in hippocampal tissues of epilepsy rats, increased number of apoptotic neurons and significantly decreased the number of surviving neurons.

Conclusion

Our study provides evidence that the inhibition of miR-103a can inhibit the activation of astrocytes in hippocampus tissues and improve the pathological injury of neurons of epilepsy rats by regulating BDNF gene.

Electronic supplementary material

The online version of this article (10.1186/s12935-019-0821-2) contains supplementary material, which is available to authorized users.

Electron beam damage of perfluorosulfonic acid studied by soft X-ray spectromicroscopy

Scanning transmission X-ray microscopy (STXM) was used to study chemical changes to perfluorosulfonic acid (PFSA) spun cast thin films as a function of dose imparted by exposure of a 200 kV electron beam in a Transmission Electron Microscope (TEM). The relationship between electron beam fluence and absorbed dose was calibrated using a modified version of a protocol based on the positive to negative lithography transition in PMMA [Leontowich et al, J. Synchrotron Rad. 19 (2012) 976]. STXM was used to characterize and quantify the chemical changes caused by electron irradiation of PFSA under several different conditions. The critical dose for CF₂-CF₂ amorphization was used to explore the effects of the sample environment on electron beam damage. Use of a silicon nitride substrate was found to increase the CF₂-CF₂ amorphization critical dose by ∼x2 from that for free-standing PFSA films. Freestanding PFSA and PMMA films were damaged by 200 kV electrons at ∼100 K and then the damage was measured by STXM at 300 K (RT). The lithography cross-over dose for PMMA was found to be ∼2x higher when the PMMA thin film was electron irradiated at 120 K rather than at 300 K. The critical dose for CF₂-CF₂ amorphization in PFSA irradiated at 120 K followed by warming and delayed measurement by STXM at 300 K was found to be ∼2x larger than at 300 K. To place these results in the context of the use of electron microscopy to study PFSA ionomer in fuel cell systems, an exposure of 300 e^-/nm² at 300 K (which corresponds to an absorbed dose of ∼20 MGy) amorphizes ∼10% of the CF₂-CF₂ bonds in PFSA. At this dose level, the spatial resolution for TEM imaging of PFSA is limited to 3.5 nm by radiation damage, if one is using a direct electron detector with DQE = 1. This work recommends caution about 2D and 3D morphological information of PFSA materials based on TEM studies which use fluences higher than 300 e^-/nm².

Wavelet transform-based electron tomography measurement of buried interface roughness

Interface roughness is a critical parameter determining the performance of semiconductor devices. We show that a continuous wavelet transform is useful to describe not only the magnitude of the interface roughness, but also the spatial frequencies that describe the interface. We propose a simple presentation of the results that makes it convenient to compare between interfaces. In particular, an average and maximum value wavelet profile that is obtained from a series of one dimensional wavelet transforms provides a traceable and quick survey of the results. We demonstrate the wavelet transform method using both computer simulations and by applying it to experimental data obtained by electron tomography of a test sample and to a molecular layer interface. Wavelet descriptions of the interface roughness suffers less from the presence of shot noise in the experimental data than the traditional root mean square error description of interface roughness. An increase in lateral dimensions of an interface that has large features increases the content of low spatial frequencies in wavelet transforms. In comparison, the value of root mean square error increases in an untraceable manner with the same increase in lateral dimensions on the same interface. Morse wavelets with γ = 9 and β = 3 appear to be a suitable choice for applications in interface roughness measurement.

Arbuscular mycorrhizal fungi alleviate the heavy metal toxicity on sunflower (Helianthus annuus L.) plants cultivated on a heavily contaminated field soil at a WEEE-recycling site

An 8-week pot experiment was conducted to investigate the growth and responses of sunflower (Helianthus annuus L.) to arbuscular mycorrhizal (AM) fungal inoculations on a heavily heavy metal (HM)-contaminated (H) soil and a lightly HM-enriched (L) soil, both of which were collected from a waste electrical and electronic equipment (WEEE)-recycling site. Compared with the L soil, the H soil induced significantly larger (P<0.05) concentrations of Cd, Cu, Pb, Cr, Zn and Ni in sunflower (except for root Cr and shoot Ni), which impaired the thylakoid lamellar folds in leaves. The biomasses and P concentrations of shoots and roots, as well as the total P acquisitions per pot were all significantly decreased (P<0.05). Both Funneliformis mosseae (Fm) and F. caledonium (Fc) inoculation significantly increased (P<0.05) root mycorrhizal colonization. For the L soil, AM fungal inoculations had no significant effects on the soil-plant system, except for a decrease of soil pH and increases of soil available P and DTPA-extractable Zn concentrations with the Fm-inoculated treatment. For the H soil, however, AM fungal inoculations significantly increased (P<0.05) the biomasses and P concentrations of shoots and roots, as well as the total P acquisitions per pot, and significantly reduced (P<0.05) the concentrations of HMs in shoots (except for Cu and Pb with Fm- and Fc- inoculated treatments, respectively) and alleviated the toxicity symptoms of HMs in thylakoid structure of leaves. AM fungal inoculations in the H soil also significantly increased (P<0.05) the shoot uptake of HMs (except for Cr), and tended to decrease the total concentrations of HMs in soils. This suggests the potential application of AM fungi for both reducing HM stress and promoting phytoextraction of HM-contaminated soils caused by WEEE recycling.

Influence of salts and metal nanoparticles on the activity and thermal stability of a recombinant chitinase from Stenotrophomonas maltophilia N4

Cells of Escherichia coli Rosetta, containing plasmid pET-28a with sequences of DNA of chitinase from Stenotrophomonas maltophilia N4, were used for the efficient synthesis of recombinant chitinolytic enzyme. The objective of this study was to improve thermal stability of the recombinant chitinase by salts and metal nanoparticles (NP). The studied chitinase was thermolabile and largely lost its activity in the first minutes of storage at 50 and 60 °C. The optimum temperature for colloidal chitin hydrolysis by the enzyme was 50 °C. Application of sodium aurothiomalate hydrate and manganese chloride enhanced the activity of the recombinant enzyme. In general, chitinase activity was higher when silver nanoparticles (Ag-NP) were used, but lower for other NP. The thermal stability of chitinase immobilized on Ag-NP and manganese chloride was significantly higher than that of free chitinase. Chitinase thermal stability after gold and manganese oxide nanoparticle application was higher than that of the control at 50 °C. Platinum nanoparticles had no significant effect on thermostability. The Ag-NP had a smaller diameter (from 2 to 20 nm) than Au-NP (from 5 to 70 nm) and Pt-NP (from 4 to 80 nm). The TEM analysis showed that the used NP had a higher affinity for chitinase than for the synthetic substrate. The type, size, and location of the NP on the enzyme played a major role in the thermal stability of chitinase.

Computational segmentation of collagen fibers in bone matrix indicates bone quality in ovariectomized rat spine

Bone loss varies according to disease and age and these variations affect bone cells and extracellular matrix. Osteoporosis rat models are widely investigated to assess mechanical and structural properties of bone; however, bone matrix proteins and their discrepant regulation of diseased and aged bone are often overlooked. The current study considered the spine matrix properties of ovariectomized rats (OVX) against control rats (Sham) at 16 months of age. Diseased bone showed less compact structure with inhomogeneous distribution of type 1 collagen (Col1) and changes in osteocyte morphology. Intriguingly, demineralization patches were noticed in the vicinity of blood vessels in the OVX spine. The organic matrix structure was investigated using computational segmentation of collagen fibril properties. In contrast to the aged bone, diseased bone showed longer fibrils and smaller orientation angles. The study shows the potential of quantifying transmission electron microscopy images to predict the mechanical properties of bone tissue.

The effect of dense phase carbon dioxide on the conformation of hemoglobin

Dense phase carbon dioxide (DPCD) sterilization is a non-thermal sterilization technology used to process heat-sensitive foods. Although nutritional and sensorial quality of food is preserved while unwanted microbial activity is reduced during DPCD sterilization, the effect on protein structure remains unclear. In this work, the effect of DPCD on the higher order structure and fluorescence properties of Hemoglobin (Hb) was investigated. The different conditions assessed during DPCD processing included variation in pressure, pH and heating conditions. Results from this study showed an inversely proportional correlation between α-helical content of Hb and pressure. As the pressure was lowered, the levels of α-helical content increased. The increased levels of α-helix correlated with a lower fluorescence intensity and a limited redshift in the fluorescence emission wavelength. TEM imaging showed that DPCD processing resulted in Hb with larger molecular diameters, which became smaller as the pressure increased. Interestingly, after 7-day storage at 4 °C, an increase in α-helical content was observed. Results from this work show that DPCD sterilization does impact the conformation of hemoglobin, with a notable impact on secondary and tertiary structure.

Isolation and identification of Penicillium chrysogenum strain Y5 and its copper extraction characterization from waste printed circuit boards

Biohydrometallurgy is generally considered as a green technology for the recycling of industrial solid waste. In this study, an indigenous fungal strain named Y5 with the ability of high-yielding organic acids was isolated and applied in bioleaching of waste printed circuit boards (PCBs). The strain Y5 was identified as Penicillium chrysogenum by morphological and molecular identification. Meanwhile, we investigated that an optimal set of culturing conditions for the fungal growth and acids secretion was 15 g/L glucose with initial pH 5.0, temperature 25°C and shaking speed 120 rpm in shaken flasks culture. Moreover, three bioleaching processes such as one-step, two-step and spent medium processes were conducted to extract copper from waste PCBs. Spent medium bioleaching showed higher copper extraction percentage and it was 47% under 5%(w/v) pulp density. Transmission electron microscope (TEM) observation combining with energy dispersive analysis of X-rays (EDAX) showed that the leached metal ions did not obviously damage the hypha cells. All above results indicated that P.chrysogenum strain Y5 has the tolerance to metal ions, suggesting its potential in recycling of metals from waste PCBs in industry.

In situ investigation of bismuth nanoparticles formation by transmission electron microscope

Bismuth (Bi) nanoparticles are prepared by using NaBi(MoO₄)₂ nanosheets in the beam of electrons emitted by transmission electron microscope. The formation and growth of Bi nanoparticles are investigated in situ. The sizes of Bi nanoparticles are confined within the range of 6-10nm by controlling irradiation time. It is also observed that once the diameter of nanoparticles is larger than 10nm, the Bi particles are stable as a result of the immobility of large nanoparticles. In addition, some nanoparticles on the edges form nanorods, which are explained as the result of a coalescence process, if the irradiation period is longer than 10min. The in situ research on Bi nanoparticles facilitates in-depth investigations of the physicochemical behavior and provides more potential applications in various fields such as sensors, catalysts and optical devices.

Spectral and raw quasi in-situ energy dispersive X-ray data captured via a TEM analysis of an ODS austenitic stainless steel sample under 1 MeV Kr2+ high temperature irradiation

The data presented in this article is related to the research experiment, titled: ‘Quasi in-situ energy dispersive X-ray spectroscopy observation of matrix and solute interactions on Y-Ti-O oxide particles in an austenitic stainless steel under 1 MeV Kr²⁺ high temperature irradiation’ (Brooks et al., 2017) [1]. Quasi in-situ analysis during 1 MeV Kr²⁺ 520 °C irradiation allowed the same microstructural area to be observed using a transmission electron microscope (TEM), on an oxide dispersion strengthened (ODS) austenitic stainless steel sample. The data presented contains two sets of energy dispersive X-ray spectroscopy (EDX) data collected before and after irradiation to 1.5 displacements-per-atom (~1.25×10⁻³ dpa/s with 7.5×10¹⁴ ions cm⁻²). The vendor software used to process and output the data is the Bruker Esprit v1.9 suite. The data includes the spectral (counts vs. keV energy) of the quasi in-situ scanned region (512×512 pixels at 56k magnification), along with the EDX scanning parameters. The.raw files from the Bruker Esprit v1.9 output are additionally included along with the.rpl data information files. Furthermore included are the two quasi in-situ HAADF images for visual comparison of the regions before and after irradiation. This in-situ experiment is deemed ‘quasi’ due to the thin foil irradiation taking place at an external TEM facility. We present this data for critical and/or extended analysis from the scientific community, with applications applying to: experimental data correlation, confirmation of results, and as computer based modeling inputs.

Laminaria Japonica Polysaccharides effectively inhibited the growth of nasopharyngeal carcinoma cells in vivo and in vitro study

AIMS

Laminaria Japonica Polysaccharides (LJP) is a kind of plant polysaccharide isolated from Laminaria Japonica Aresch. LJP has a variety of biological activity, including anti-tumor, improving immune function, anti-radiation and others. This study observed the biological activity of LJP in vitro and in vivo on human nasopharyngeal carcinoma(NPC), and the possible anticancer mechanism was explored.

METHODS

Nasopharyngeal poorly differentiated squamous cell carcinoma cell lines CNE2 and HONE1 were used for the study. MTT method was used to detect the proliferation of HONE1 and CNE2 treated with gradient concentrations of LJP. The apoptosis of HONE1 treated with LJP was detected by annexin V-FITC/PI double staining method. HONE1 was used to establish subcutaneous implanted tumor model in nude mice. The changes of transplanted tumor volume and body weight of nude mice in each group were observed and recorded. The changes of the ultrastructure of transplanted tumor were observed by transmission electron microscope (TEM).

RESULTS

MTT results showed that LJP has inhibitory effect on proliferation of both HONE1 and CNE2, and the effects were dosage-dependent; results of flow cytometry (FCM) analysis showed that, LJP could efficient induce apoptosis in HONE1, and apoptosis rate increased with the increase of LJP concentration. In vivo experiments, the inhibition rate was 33.7% (P<0.05) and 47% (P<0.01) in middle and high dose LJP group, respectively. TEM results suggested that the cancer cells in the transplanted tumor tissue treated with middle and high dose LJP presented unique apoptosis changes.

CONCLUSIONS

LJP can effectively inhibit the growth of NPC cells. And it may be achieved by inducing apoptosis of NPC cells.

Influence of perfluorocarbons on Carbamazepine and Benzodiazepine for a neuro-lung protective strategy

Lennox-Gastaut syndrome (LGS) is commonly characterized by a triad of features including multiple seizure types, intellectual disability or regression. LGS type of seizures is epilepsy which is due to abnormal vibrations occurring in seizures. During the time of such abnormal vibrations, both the seizures and the lungs suffer a lack in oxygen content to a considerable extent. This results in prolonged vibrations and loses of nervous control. As a neuro-lung protective strategy, a novel attempt has been made to enrich both seizures and lungs with oxygen content through the support of Perfluorodecalin (an excellent oxygen carrier) C₁₀F₁₈ (PFD) and Perfluorohexane C₆F₁₄ (PFH) along with an enhancement in the antiepileptic activity by the two chosen antiepileptic drugs (AEDs) Carbamazepine (CBZ) and Benzodiazepine (BDZ). Perfluorodecalin C₁₀F₁₈ (PFD) and Perfluorohexane C₆F₁₄ (PFH) emulsions were prepared by sonication process with combination of nonionic emulsifier, Lecithin (l-α-phosphatidylcholine) as a surfactant in Aqueous phase medium. These emulsions were mixed with Carbamazepine (CBZ) and Benzodiazepine (BDZ) drugs maintained at a temperature of about -20°C to 20°C and were set to slow evaporation process. The products are subjected to Optical microscope, Transmission electron microscopy (TEM) and Scanning Electron Microscope (SEM) - Energy dispersive X-ray Spectroscopy (EDS). Study reveals the co-existence of fluorine and drug ensuring the oxygen uptake by the drug. Morphology of TEM, Optical microscopic images and the particle diameter estimated through Image_J confirms this analysis.

Relevant principal factors affecting the reproducibility of insect primary culture

The primary culture of insect cells often suffers from problems with poor reproducibility in the quality of the final cell preparations. The cellular composition of the explants (cell number and cell types), surgical methods (surgical duration and surgical isolation), and physiological and genetic differences between donors may be critical factors affecting the reproducibility of culture. However, little is known about where biological variation (interindividual differences between donors) ends and technical variation (variance in replication of culture conditions) begins. In this study, we cultured larval fat bodies from the Japanese rhinoceros beetle, Allomyrina dichotoma, and evaluated, using linear mixed models, the effect of interindividual variation between donors on the reproducibility of the culture. We also performed transcriptome analysis of the hemocyte-like cells mainly seen in the cultures using RNA sequencing and ultrastructural analyses of hemocytes using a transmission electron microscope, revealing that the cultured cells have many characteristics of insect hemocytes.

Bioengineered silver nanoparticles using Curvularia pallescens and its fungicidal activity against Cladosporium fulvum

Microorganisms based biosynthesis of nanomaterials has triggered significant attention, due to their great potential as vast source of the production of biocompatible nanoparticles (NPs). Such biosynthesized functional nanomaterials can be used for various biomedical applications. The present study investigates the green synthesis of silver nanoparticles (Ag NPs) using the fungus Curvularia pallescens (C. pallescens) which is isolated from cereals. The C. pallescens cell filtrate was used for the reduction of AgNO₃ to Ag NPs. To the best of our knowledge C. pallescens is utilized first time for the preparation of Ag NPs. Several alkaloids and proteins present in the phytopathogenic fungus C. pallescens were mainly responsible for the formation of highly crystalline Ag NPs. The as-synthesized Ag NPs were characterized by using UV–Visible spectroscopy, X-ray diffraction and transmission electron microscopy (TEM). The TEM micrographs have revealed that spherical shaped Ag NPs with polydisperse in size were obtained. These results have clearly suggested that the biomolecules secreted by C. pallescens are mainly responsible for the formation and stabilization of nanoparticles. Furthermore, the antifungal activity of the as-prepared Ag NPs was tested against Cladosporium fulvum, which is the major cause of a serious plant disease, known as tomato leaf mold. The synthesized Ag NPs displayed excellent fungicidal activity against the tested fungal pathogen. The extreme zone of reduction occurred at 50 μL, whereas, an increase in the reduction activity is observed with increasing the concentration of Ag NPs. These encouraging results can be further exploited by employing the as synthesized Ag NPs against various pathogenic fungi in order to ascertain their spectrum of fungicidal activity.

Ultra-structural effects of different low-level lasers on normal cultured human melanocytes: an in vitro comparative study

The aim of this study was to investigate the effects of the different types of low-level laser therapy (LLLT) on the ultra-structure and number of melanosomes in normal cultured human melanocytes. Specific effects of various types of LLLT on the ultra-structure of melanosomes have not yet been reported. Melanocytes were exposed to LLLT at an energy level of 2.0 J/cm², using a blue (457 nm), red (635 nm), or ultraviolet (UV) (355 nm) laser. After 72 h of irradiation, the melanocytes were fixed in 2.5 % glutaraldehyde (pH 7.2) phosphate buffer for 8 h and analyzed by transmission electron microscopy. Four developmental stages (I to IV) of melanosomes were observed, and their numbers were counted manually. The percentage of stages I, II, III, and IV melanosomes was 12.8, 14.2, 22.6, and 50.3 %, respectively, in the control (sham light). However, the melanosome percentages were 41.2, 5.4, 8.2, and 24.2 % in stages I, II, III, and IV, respectively, in the blue laser-treated group; 58.4, 6.1, 9.3, and 26.2 % for stages I, II, III, and IV, respectively, in the red laser-treated group; and 31.3, 11.1, 16.5, and 41.1 % for stages I, II, III, and IV, respectively, in the UV laser-treated group. The present data show that the amount of stage I is significantly higher (P < 0.0001) in the LLLT-treated cells compared to the control, which indicates significant stimulation of melanogenesis. The red laser was more effective than the other lasers. Moreover, the effects of LLLT on the ultra-structure of melanosomes need to be studied in a larger number of subject groups.

Designs for a quantum electron microscope

One of the astounding consequences of quantum mechanics is that it allows the detection of a target using an incident probe, with only a low probability of interaction of the probe and the target. This 'quantum weirdness' could be applied in the field of electron microscopy to generate images of beam-sensitive specimens with substantially reduced damage to the specimen. A reduction of beam-induced damage to specimens is especially of great importance if it can enable imaging of biological specimens with atomic resolution. Following a recent suggestion that interaction-free measurements are possible with electrons, we now analyze the difficulties of actually building an atomic resolution interaction-free electron microscope, or "quantum electron microscope". A quantum electron microscope would require a number of unique components not found in conventional transmission electron microscopes. These components include a coherent electron beam-splitter or two-state-coupler, and a resonator structure to allow each electron to interrogate the specimen multiple times, thus supporting high success probabilities for interaction-free detection of the specimen. Different system designs are presented here, which are based on four different choices of two-state-couplers: a thin crystal, a grating mirror, a standing light wave and an electro-dynamical pseudopotential. Challenges for the detailed electron optical design are identified as future directions for development. While it is concluded that it should be possible to build an atomic resolution quantum electron microscope, we have also identified a number of hurdles to the development of such a microscope and further theoretical investigations that will be required to enable a complete interpretation of the images produced by such a microscope.

Purification and immuno-gold labeling of lily mottle virus from lily leaves

Lily mottle virus (LMoV) is prevalent in Lilium species worldwide causing dwarfing, flower breaking, and reduced bulb yield. In this paper, an easy to use and efficient procedure is described for purification of LMoV from lily leaves. The resulting sample is characterized by a 260/280 nm absorbance ratio of 1.20 at a concentration of 1.27 mg/ml. The procedure results in high protein purity and particle integrity as shown by UV-spectrophotometry, polyacrylamide gel electrophoresis (PAGE), Western blotting, reverse transcriptase (RT)-PCR and transmission electron microscopy (TEM) in combination with immuno-gold labeling. This is the first time that an immuno-gold labeling (IGL) assay was performed to identify a virus of lily. Purified products can be used as a source of antigen in the preparation of antibodies against LMoV and may assist in the development of a diagnostic test for LMoV and in epidemiological surveys.

In vitro exposure of haemocytes of the clam Ruditapes philippinarum to titanium dioxide (TiO2) nanoparticles: nanoparticle characterisation, effects on phagocytic activity and internalisation of nanoparticles into haemocytes

The continuous growth of nanotechnology and nano-industries, the considerable increase of products containing nanoparticles (NPs) and the potential release of NPs in aquatic environments suggest a need to study NP effects on aquatic organisms. In this context, in vitro assays are commonly used for evaluating or predicting the negative effects of chemicals and for understanding their mechanisms of action. In this study, a physico-chemical characterisation of titanium dioxide NPs (n-TiO2) was performed, and an in vitro approach was used to investigate the effects of n-TiO2 on haemocytes of the clam Ruditapes philippinarum. In particular, the effects on haemocyte phagocytic activity were evaluated in two different experiments (with and without pre-treatment of haemocytes) by exposing cells to P25 n-TiO2 (0, 1 and 10 μg/mL). In addition, the capability of n-TiO2 to interact with clam haemocytes was evaluated with a transmission electron microscope (TEM). In this study, n-TiO2 particles showed a mean diameter of approximately 21 nm, and both anatase (70%) and rutile (30%) phases were revealed. In both experiments, n-TiO2 significantly decreased the phagocytic index compared with the control, suggesting that NPs are able to interfere with cell functions. The results of the TEM analysis support this hypothesis. Indeed, we observed that TiO2 NPs interact with cell membranes and enter haemocyte cytoplasm and vacuoles after 60 min of exposure. To the best of our knowledge, this is the first study demonstrating the internalisation of TiO2 NPs into R. philippinarum haemocytes. The present study can contribute to the understanding of the mechanisms of action of TiO2 NPs in bivalve molluscs, at least at the haemocyte level.

Age-related morphological changes in the basement membrane in the stria vascularis of C57BL/6 mice

Basement membrane anionic sites (BMAS) are involved in the selective transport of electrically charged macromolecules in cochlear capillaries. Using cationic polyethyleneimine (PEI), we examined age-related changes in BMAS in the cochleae of C57BL/6 mice. The mice were grouped according to age as follows: 3 days, 4 weeks, 8 weeks, 6 months, and 12 months. In the right bony labyrinths, widths of the stria vascularis were measured in paraffin-embedded sections using light microscopy. The left bony labyrinths were immersed in a 0.5 % cationic PEI solution and embedded in epoxy resin. Ultrathin sections of the left cochlea were examined using transmission electron microscopy. A significant difference in stria vascularis width was observed between the 4-week-old and 12-month-old mice. The PEI distribution in the capillary and epithelial basement membranes (BMs) of the cochlea was observed. In all animals, PEI particles were evenly distributed in the capillary BM of the spiral ligament and in the subepithelial BM of Reissner's membrane. In the stria vascularis, PEI particles were evenly distributed in the capillary BM in 3-day-old mice. In 4- and 8-week-old mice, PEI particle sizes were markedly lower than those observed in 3-day-old mice. In 6- and 12-month-old mice, PEI particles were hardly detected in the strial capillary BM. In the strial capillary BM in these mice, the laminae rarae externa and interna disappeared, but the lamina densa became larger. We speculated that age-related changes of strial capillary BMAS may affect electrically charged macromolecule transport systems in the stria vascularis of C57BL/6 mice.

ETM study of electroporation influence on cell morphology in human malignant melanoma and human primary gingival fibroblast cells

OBJECTIVE

To estimate electroporation (EP) influence on malignant and normal cells.

METHODS

Two cell lines including human malignant melanoma (Me-45) and normal human gingival fibroblast (HGFs) were used. EP parameters were the following: 250, 1 000, 1 750, 2 500 V/cm; 50 µs by 5 impulses for every case. The viability of cells after EP was estimated by MTT assay. The ultrastructural analysis was observed by transmission electron microscope (Zeiss EM 900).

RESULTS

In the current study we observed the intracellular effect following EP on Me-45 and HGF cells. At the conditions applied, we did not observe any significant damage of mitochondrial activity in both cell lines treated by EP. Conversely, we showed that EP in some conditions can stimulate cells to proliferation. Some changes induced by EP were only visible in electron microscopy. In fibroblast cells we observed significant changes in lower parameters of EP (250 and 1 000 V/cm). After applying higher electric field intensities (2 500 V/cm) we detected many vacuoles, myelin-like bodies and swallowed endoplasmic reticulum. In melanoma cells such strong pathological modifications after EP were not observed, in comparison with control cells. The ultrastructure of both treated cell lines was changed according to the applied parameters of EP.

CONCLUSIONS

We can claim that EP conditions are cell line dependent. In terms of the intracellular morphology, human fibroblasts are more sensitive to electric field as compared with melanoma cells. Optimal conditions should be determined for each cell line. Summarizing our study, we can conclude that EP is not an invasive method for human normal and malignant cells. This technique can be safely applied in chemotherapy for delivering drugs into tumor cells.

Abnormal ultrastructure of intestinal epithelial barrier in mice with alcoholic steatohepatitis

Intestinal barrier dysfunction caused by chronic alcohol consumption is closely associated with disruption of the intestinal epithelial apical junction complex. The present study was undertaken to directly display by transmission electron microscopy the abnormal ultrastructure of the intestinal epithelial barrier in mice with alcoholic steatohepatitis. The results showed that chronic alcohol consumption could induce obvious liver injury, with diffuse lipid accumulation and focal inflammatory cell infiltration in the liver, assessed by hematoxylin and eosin staining. The indicators of intestinal barrier dysfunction, d-lactic acid and lipopolysaccharide, were significantly higher in alcohol-fed mice than in control mice. Alcohol exposure obviously caused high permeability in the ileum to fluorescein isothiocyanate-dextran (FD-4; molecular weight 4000). Transmission electron microscopy demonstrated that tight junctions and adherens junctions expanded noticeably in alcohol-fed mice. Although the tight junction (TJ) length of alcohol-fed mice had no significant difference compared with control mice, the adherens junction (AJ) length of alcohol-fed mice significantly decreased compared with control mice. Additionally, the ratios of both TJmax/TJmin and AJmax/AJmin were significantly larger in alcohol-fed mice than in control liquid-fed mice. In conclusion, high intestinal permeability caused by alcohol attributes to the irregular ultrastructure of the intestinal epithelial barrier.

Effect of Nigella sativa alcoholic extract and oil, as well as Phaseolus vulgaris (kidney bean) lectin on the ultrastructure of Trichomonas vaginalis trophozoites

Trichomonas vaginalis is a parasitic protozoan that is the aetiological agent of trichomoniasis, the most common non-viral sexually transmitted disease worldwide. Currently, the compound of choice for the treatment of T. vaginalis infections is metronidazole, however, it has many side effects and an increase in metronidazole-resistant trichomoniasis has been observed. Medicinal plants could be a source of new antiprotozoal drugs with high activity, low toxicity and lower price. The present work was carried out to investigate the therapeutic potential of Nigella sativa alcoholic extract and oil, as well as Phaseolus vulgaris (kidney bean) lectin and their in vitro activity on the ultrastructure of T. vaginalis trophozoites in comparison to metronidazole, as detected by transmission electron microscope. Both N. sativa oil and P. vulgaris lectin showed high toxic effect as evidenced by severe cell damage with cytoplasmic and nuclear destruction, while the effect of N. sativa alcoholic extract was moderate. Therefore, these two extracts could offer an effective, cheaper and more safe alternative for metronidazole in treatment of trichomoniasis.

Hybrid fluorescence and electron cryo-microscopy for simultaneous electron and photon imaging

Integration of fluorescence light and transmission electron microscopy into the same device would represent an important advance in correlative microscopy, which traditionally involves two separate microscopes for imaging. To achieve such integration, the primary technical challenge that must be solved regards how to arrange two objective lenses used for light and electron microscopy in such a manner that they can properly focus on a single specimen. To address this issue, both lateral displacement of the specimen between two lenses and specimen rotation have been proposed. Such movement of the specimen allows sequential collection of two kinds of microscopic images of a single target, but prevents simultaneous imaging. This shortcoming has been made up by using a simple optical device, a reflection mirror. Here, we present an approach toward the versatile integration of fluorescence and electron microscopy for simultaneous imaging. The potential of simultaneous hybrid microscopy was demonstrated by fluorescence and electron sequential imaging of a fluorescent protein expressed in cells and cathodoluminescence imaging of fluorescent beads.

Photocatalytic degradation of methylene blue with Fe doped ZnS nanoparticles

Fe doped ZnS nanoparticles (Zn1-xFexS; where x=0.00, 0.03, 0.05 and 0.10) were synthesized by a chemical precipitation method. The synthesized products were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope, UV-Vis and photoluminescence spectrometer. The X-ray diffraction and transmission electron microscope studies show that the size of crystallites is in the range of 2-5 nm. Photocatalytic activities of ZnS and 3, 5 and 10 mol% Fe doped ZnS were evaluated by decolorization of methylene blue in aqueous solution under ultraviolet and visible light irradiation. It was found that the Fe doped ZnS bleaches methylene blue much faster than the undoped ZnS upon its exposure to the visible light as compared to ultraviolet light. The optimal Fe/Zn ratio was observed to be 3 mol% for photocatalytic applications.

Turning an antiviral into an anticancer drug: nanoparticle delivery of acyclovir monophosphate

Anti-herpes simplex virus (HSV) drug acyclovir (ACV) is phosphorylated by the viral thymidine kinase (TK), but not the cellular TK. Phosphorylated ACV inhibits cellular DNA synthesis and kills the infected cells. We hypothesize that ACV monophosphate (ACVP), which is an activated metabolite of ACV, should be efficient in killing cells independent of HSV-TK. If so, ACVP should be a cytotoxic agent if properly delivered to the cancer cells. The Lipid/Calcium/Phosphate (LCP) nanoparticles (NPs) with a membrane/core structure were used to encapsulate ACVP to facilitate the targeted delivery of ACVP to the tumor. The LCP NPs showed entrapment efficiency of ~70%, the nano-scaled particle size and positive zeta potential. Moreover, ACVP-loaded LCP NPs (A-LCP NPs) exhibited concentration-dependent cytotoxicity against H460 cells and increased S-phase arrest. More importantly, a significant reduction of the tumor volume over 4 days following administration (p<0.05-0.005) of A-LCP NPs, suggests excellent in vivo efficacy. Whereas, two free drugs (ACV and ACVP) and blank LCP NPs showed little or no therapeutic effect. It was also found that the high efficacy of A-LCP NPs was associated with the ability to induce dramatic apoptosis of the tumor cells, as well as significantly inhibit tumor cell proliferation and cell cycle progression. In conclusion, with the help of LCP NPs, monophosphorylation modification of ACV can successfully modify an HSV-TK-dependent antiviral drug into an anti-tumor drug.

High-precision alignment of electron tomography tilt series using markers formed in helium-ion microscope

Tungsten nanodots formed in a helium-ion microscope (HIM) provide a practical means of aligning markers of electron tomography tilt series with a high degree of precision. The nanodots were formed using a HIM equipped with a W(CO)6 gas injection system, enabling the precise placement of the nanodots at desired locations of a sample. Template matching was applied to the markers formed in the HIM to detect the positions automatically. The relation between the positions of the markers and the accuracy of the alignment was also determined in order to achieve precise alignment. The method was applied to the markers in order to reconstruct three-dimensional (3D) images of a rod-shaped specimen that contained a 65-nm-diameter via structure in a Cu/Low-k interconnect.

Primary oral Penicillium marneffei infection diagnosed by PCR-based molecular identification and transmission electron microscopic observation from formalin-fixed paraffin-embedded tissues

We report a case of primary oral Penicillium marneffei infection in a 39-year-old man without HIV infection. Although fungal culture was negative, the patient was finally confirmed to have P. marneffei infection by PCR-based molecular identification and transmission electron microscopic observation from formalin-fixed, paraffin-embedded tissues. The patient was cured with taking itraconazole for 3 months.

A sensitive assay for ornithine amino transferase in rat brain mitochondria by ninhydrin method

To establish/develop an assay method for measuring Ornithine Aminotransferase (EC.2.6.1.13) activity using rat brain mitochondria as a source of enzyme in presence and absence of Pyridoxal Phosphate (PLP). The modified method, with the improved sensitivity, is adopted for the assay of ornithine amino transferase activity in rat brain mitochondria. The enzyme activity was measured at 620 nm, the study showed that reaction was optimum at 37°C for 30 minutes. The assay is sensitive enough to detect activity at the order of nanomoles pyrroline-5-carboxylate/mg protein/minute and can be compared as an alternative to the radio isotopic method which is more cumbersome and aminobenzaldehyde method which is less sensitive. The K(m) & V(max) shows maximum activity in the presence of Pyridoxal Phosphate (Coenzyme) concentration at 0.05mM when compared with absence of Pyridoxal Phosphate as higher the concentration of Pyridoxal Phosphate affects the affinity of the enzyme to substrate. The OAT activity in different tissues of the rat was also studied and highest activity was found in liver and kidney.

Ultrastructural view of colon anastomosis under propolis effect by transmission electron microscopy

AIM: To evaluate the effect of propolis administration on the healing of colon anastomosis with light and transmission electron microscopes.

METHODS: Forty-eight Wistar-Albino female rats were divided into two groups and had colon resection and anastomosis. In group I, rats were fed with standard rat chow pre- and postoperatively. The rats in group II were fed with standard rat chow and began receiving oral supplementation of propolis 100 mg/kg per day beginning 7 d before the operation and continued until they were sacrificed. Rats were sacrificed 1, 3, 7 and 14 d after operation, and anastomotic bursting pressures measured. After the resection of anastomotic segments, histopathological examination was performed with light and transmission electron microscopes by two blinded histologists and photographed.

RESULTS: The colonic bursting pressures of the propolis group were statistically significantly better than the control group. Ultrastructural histopathological analysis of the colon anastomosis revealed that propolis accelerated the phases of the healing process and stimulated mature granulation tissue formation and collagen synthesis of fibroblasts.

CONCLUSION: Bursting pressure measurements and ultra structural histopathological evaluation showed that administration of propolis accelerated the healing of colon anastomosis following surgical excision.