Transmission Electron Micrographs Research Articles

C.elegans touch receptor neurons direct mechanosensory complex organization via repurposing conserved basal lamina proteins.

The sense of touch is conferred by the conjoint function of somatosensory neurons and skin cells. These cells meet across a gap filled by a basal lamina, an ancient structure found in metazoans. Using Caenorhabditis elegans, we investigate the composition and ultrastructure of the extracellular matrix at the epidermis and touch receptor neuron (TRN) interface. We show that membrane-matrix complexes containing laminin, nidogen, and the MEC-4 mechano-electrical transduction channel reside at this interface and are central to proper touch sensation. Interestingly, the dimensions and spacing of these complexes correspond with the discontinuous beam-like extracellular matrix structures observed in serial-section transmission electron micrographs. These complexes fail to coalesce in touch-insensitive extracellular matrix mutants and in dissociated neurons. Loss of nidogen reduces the density of mechanoreceptor complexes and the amplitude of the touch-evoked currents they carry. Thus, neuron-epithelium cell interfaces are instrumental in mechanosensory complex assembly and function. Unlike the basal lamina ensheathing the pharynx and body wall muscle, nidogen recruitment to the puncta along TRNs is not dependent upon laminin binding. MEC-4, but not laminin or nidogen, is destabilized by point mutations in the C-terminal Kunitz domain of the extracellular matrix component, MEC-1. These findings imply that somatosensory neurons secrete proteins that actively repurpose the basal lamina to generate special-purpose mechanosensory complexes responsible for vibrotactile sensing.

Novel Transmission Electron Microscopic Method to Quantify Protein Clustering on the Cell Surface.

The cell surface distribution patterns (clustering) of membrane proteins have been widely investigated in cell biology. Here we describe a novel transmission electron microscopic (TEM) protocol designed to improve the quality of information obtained about the protein distribution patterns detected. This novel method makes it possible to study the clustering of all transmembrane proteins on one half of the cytoplasmic membrane of a whole cell. To achieve better imaging, we combine various methods, including critical-point drying, fixation of gold beads with a carbon layer, and a newly developed chemical thinning method. In addition, in our image-processing algorithm, we implemented pair correlation and pair cross-correlation functions, providing more details and better quantitative accuracy in characterizing the size and numbers of possible protein clusters. © 2024 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Sample preparation and transmission electron micrography Alternate Protocol: Direct cell labeling for transmission electron micrography Basic Protocol 2: Analysis of TEM images to detect immunogold-labeled proteins.

Cell-Free Hemoglobin Induces Vascular and Mitochondrial Dysfunction in the Pulmonary Endothelium in an Oxidation-State Dependent Manner

Background: Sepsis results in significant organ damage due in part to a breakdown in endothelial vascular function. Elevated levels of cell-free hemoglobin (CFH) drive endothelial dysfunction in the lungs. CFH generates reactive oxygen species (ROS) via the iron present in the heme moiety, which can be oxidized from ferrous (CFH2+) to ferric (CFH3+). Recent studies suggest mitochondrial dysfunction may be a key pathway leading to microvascular dysfunction. We hypothesize that CFH induces mitochondrial dysfunction and microvascular endothelial barrier disruption in the lung in an oxidative-state dependent manner. Methods: CFH was converted from CFH2+ to CFH3+ by UV irradiation (validated by spectrophotometry). Primary human lung microvascular endothelial cells (HLMVECs) were treated with 1.0 mg/mL CFH2+, CFH3+, or vehicle control. Barrier dysfunction was measured via electric cell-substrate impedance sensing (ECIS) and express permeability test (XPerT) at 24h. We quantified mitochondrial superoxide (MitoSOX Red; 5 uM) by flow cytometry (1, 6, 24h) and total cellular ROS production (CellROX Deep Red; 5 uM) by fluorescence microscopy (6 and 24 h). Mitochondrial morphology (electron density, roundness, area, circularity, and aspect ratio) was assessed by transmission electron micrographs at 6h and quantified by a blinded reviewer (ImageJ). Activation of the mitochondrial permeability transition pore (mPTP) was assessed by flow cytometry using calcein-AM with cobalt chloride. DNA was purified from patient plasma and the copy number of mitochondrial genes ND4L and CYB was quantified by digital droplet PCR. Results: In HLMVECs, CFH generated excess ROS (CellROX and MitoSOX) at 6h compared to vehicle (522 vs 265 MFI, p < 0.01). Morphology analysis demonstrated increased electron density and aspect ratio and decreased circularity and roundness. mPTP activity was increased by CFH3+ (1295 vs 2197 MFI, p < 0.01) compared to vehicle or CFH2+. Barrier dysfunction caused by CFH3+ measured by ECIS peaked at 6h (-1270 vs 262 max TER drop, p < 0.0001), while XPerT confirmed dysfunction at 24h (9.41e+06 vs 6.53e+05 total fluorescent area, p < 0.01). Quantification of mtDNA copy number in patient plasma revealed that circulating mt-ND4L copies correlate with CFH (r = 0.44, p < 0.01). Conclusions: The results demonstrate significant perturbations to mitochondrial function and network dynamics caused by oxidized CFH (3+). The novel findings point towards the ferric (3+) form of hemoglobin as the primary driver of endothelial dysfunction, and the underlying mechanism is directly related to disruption of the mitochondrial network. The association of mitochondrial and vascular biomarkers demonstrates an urgent need to better understand how mitochondrial dysfunction can be prevented to limit vascular damage. This work was funded by the National Institutes of Health NHLBI 5R35HL150783 and 1F31HL167471. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Functional and ultrastretchable thermoplastic elastomeric materials: Influence of carbon dots on fluorescence, dielectric and mechanical properties

AbstractCarbon dots (CDs) are an interesting nanomaterial due to their tunable photoluminescence and other functional properties. Herein, by introducing amine‐functionalized CDs nanoparticles onto macromolecular chains of maleic anhydride grafted styrene‐ethylene‐butylene‐styrene (SEBS‐g‐MA) via a possible ring‐opening reaction of anhydride with amine, a mechanically robust and ultrastretchable thermoplastic elastomeric materials with fluorescence and dielectric functionality was developed. The amine‐functionalized CDs nanoparticles were synthesized from pyrene precursor by hydrothermal treatment. The transmission electron micrograph, Raman, Fourier transform infrared, and x‐ray photoelectron spectra confirmed the formation of highly crystalline graphitized structure of the CDs nanoparticles. Fluorescence and UV–Vis spectroscopy were used to evaluate the optical properties of the developed materials. The developed CDs/SEBS‐g‐MA nanocomposites exhibited strong intense green fluorescence compared with the pure SEBS‐g‐MA film. The thermal stability of the developed nanocomposites was improved by an increase of the Tmax by about 18°C. In addition, the developed composite showed high stretchability (strain at break ~1000%), good mechanical strength, and dielectric properties (room temperature dielectric constant ~5.2). The enhanced dielectric property of the developed composites may be due to the space charge accumulation and induced interfacial polarization at the filler–matrix interface.

Defects assisted the enhancement of optical and ferromagnetism in Zn1-xCoxS quantum dots: Toward efficient optoelectronic and spintronic applications

Colloidal Co-doped ZnS Quantum dots (QDs) were successfully synthesized through a facile and effective chemical co-precipitation method using polyethylene glycol (PEG) as a capping agent. A comprehensive study on the structure, optoelectronic, and magnetic properties of ZnS: Co2+ QDs was thoroughly carried out using diverse characterization techniques. Transmission electron micrographs reveal spherical QDs with a mean particle size of 5 ± 0.5 nm, whereas the X-ray diffraction (XRD) analysis and Raman spectroscopy confirm the exclusive presence of cubic ZnS phase structure, without any signs of Co-related impurity phases. Energy-dispersive x-ray (EDX) analysis verifies the presence of only three elements: Zinc, Cobalt, and Sulphur, with nearly stoichiometric proportions. X-ray photoemission (XPS) analysis confirmed the presence of Co2+ ions in the divalent oxidation state as well as the fair existence of sulphur vacancies. Optical measurements demonstrate that Co-doping in ZnS leads to a decrease in the optical band gap owing to the presence of defects that create localized states within the band structure. In addition, the refractive index (n) is found to increase with Co-doping level due to the increase in the polarizability. The outcomes of optical properties reveal that the tunability of the optical band gap and dispersive oscillator parameters in Co-doped ZnS QDs results in an enhancement of the non-linear optical parameters, such as third-order non-linear optical susceptibility χ(3), and non-linear refractive index n2, rendering them well-suited for applications in optoelectronic devices. Furthermore, the room-temperature photoluminescence (PL) spectra revealed that the Co-doped ZnS QDs have two broad emission bands, including the blue emission, and the green emission. By varying the level of Co-doping, it becomes possible to effectively control the relative PL intensities of dual-color emissions, highlighting their potential for producing adjustable color outputs. The room temperature ferromagnetic behaviour of the QDs has been observed and analyzed in accordance with the bound magnetic polarons model. These findings suggest that Co-doped ZnS QDs can be utilized effectively in the design of spintronic devices.

Biosynthesis, characterization and antivenom activities of <i>Moringa oleifera</i> silver nanoparticles: an experimental approach

Moringa oleifera has been previously established to possess neutralizing potentials against Echis ocellatus venom. This study however, investigated the bioefficacy of silver nanoparticles biosynthesized from M. oleifera leaf extract aimed at improving its bioactivity against E. ocellatus venom-induced toxicities using in vivo and in vitro methods. The intrinsic characteristics of the produced M. oleifera-Silver nanoparticles (MO-AgNPs) were carried out using energy dispersive X-ray, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier-transform infrared spectroscopy. Twenty-five male Wistar rats divided randomly into five groups (n=5) were used for the antivenom study. Group 1 received saline while groups 2 to 5 were envenomed intraperitoneally with 0.22mg/kg (LD50) of E. ocellatus venom. Group 2 was left untreated while groups 3 to 5 were treated with 0.2ml of antivenom, 5 and 10mg/kg MO-AgNPs post-envenomation, respectively. Blood and tissue of treated rats were analyzed for heamatological parameters and histopathology, respectively. The MO-AgNPs formation was confirmed with a colour change from light brown to yellowish-brown with maximum SPR band at 420nm from UV-Vis analysis, indicating a reflection of the bio-reduction of Ag+ to Ag0. The Transmission electron micrographs showed well dispersed spherical AgNPs with average particle size of 15.7nm. Treatment with MO-AgNPs caused a significant improvement of acute anemia, leucopenia and thrombocytopenia induced by the venom in the envenomed treated rats. Also, MO-AgNPs inhibited the haemorrhagic, haemolytic and anticoagulant activities of the venom. Tissue lesions observed in heart of envenomed untreated rats were attenuated after treatment with MO-AgNPs. The biosynthesized MO-AgNPs exhibited potent neutralizing potentials than M. oleifera crude extract against E. ocellatus venom toxicities.

Rapid Freezing and Cryo-SEM-EDS Imaging of Foraminifera (Unicellular Eukaryotes) Using a Conductive Viscous Cryogenic Glue.

Spatial distribution of water-soluble molecules and ions in living organisms is still challenging to assess. Energy-dispersive X-ray spectroscopy (EDS) via cryogenic scanning electron microscopy (cryo-SEM) is one of the promising methods to study them without loss of dissolved contents. High-resolution cryo-SEM-EDS has challenges in sample preparation, including cross-section exposure and sample drift/charging due to insulative surrounding water. The former becomes problematic for large and inseparable organisms, such as benthic foraminifera, a unicellular eukaryote playing significant roles in marine ecosystems, which often exceed the size limit for the most reliable high-pressure freezing. Here we show graphite oxide dispersed in sucrose solution as a good glue to freeze, expose cross-section by cryo-ultramicrotome, and analyze elemental distribution owing to the glue's high viscosity, adhesion force, and electron conductivity. To demonstrate the effectiveness and applicability of the glue for cryo-SEM-EDS, deep-sea foraminifer Uvigerina akitaensis was sampled during a cruise and plunge frozen directly on the research vessel, where the liquid nitrogen supply is limited. The microstructures were preserved as faithfully in cryo-SEM images as those with the conventional resin-substituted transmission electron micrograph. We found elements colocalized within the cytoplasm originating from water-soluble compounds that can be lost with conventional dehydrative fixation.

Sustainable use of plastic-derived nanocarbons as a promising larvicidal and growth inhibitor agent towards control of mosquitoes

Nanoscale carbon was obtained from six widely used plastics (PET, HDPE, PVC, LDPE, PP and PP) via thermal degradation (600 °C) under inert atmosphere. The thermally degraded products were processed through bath sonication followed by lyophilisation and the same was characterized through proximate analysis, UV–Vis spectroscopy, Scanning electron micrograph (SEM) with energy dispersive X-ray (EDX) analysis, Transmission electron micrograph (TEM), Dynamic light scattering (DLS) and Fourier transform infrared spectroscopy (FTIR). A series of aqueous solution of nanoscale carbon (5–30 mg/L) were prepared and same were used as both mosquito growth inhibitor and larvicidal agent against 3rd and 4th instar larvae of Culex pipiens. The significant percent mortality results were recorded for LDPE (p < 0.007) with average particle size of 3.01 nm and 62.95 W% of carbon and PS (p < 0.002) with average particle size of 12.80 nm and 58.73 W% of carbon against 3rd instar larvae, respectively. Similarly, for 4th instar larvae, both significant pupicidal and adulticidal activity were also recorded for PET (F = 24.0, p < 0.0001 and F = 5.73, p < 0.006), and HDPE (F = 26.0, p < 0.0001) and F = 5.30, p < 0.008). However, significant pupicidal activity were observed for PVC (F = 6.90, p < 0.003), and PS (F = 21.30, p < 0.0001). Histological, bio-chemical and microscopic studies were revealed that nanoscale carbon causes mild to severe damage of external and internal cellular integrity of larvae. However, nanoscale carbon does not exhibit any chromosomal abnormality and anatomical irregularities in Allium cepa and Cicer arietinum, respectively. Similarly, non-significant results with respect to blood cell deformation were also recorded from blood smear of Poecilia reticulata. Therefore, it can be concluded that plastic origin nanoscale carbon could be a viable sustainable nano-weapon towards control of insects.

Nanoparticulated WO3/NiWO4 Using Cellulose as a Template and Its Application as an Auxiliary Co-Catalyst to Pt for Ethanol and Glycerol Electro-Oxidation.

This work reports the use of cellulose as a template to prepare nanosized WO3 or NiWO4 and its application as a co-catalyst in the electro-oxidation of ethanol and glycerol. Microcrystalline cellulose was hydrolyzed with phosphotungstic acid (H3PW12O40) to prepare the nanocrystalline cellulose template. The latter was air-calcinated to remove the template and obtain nanometric WO3. Tungsten oxide was impregnated with Ni(NO3)2, which was subsequently air-calcinated to obtain the nanometric NiWO4. Elemental analysis confirmed the coexistence of nickel and tungsten, whereas thermal analysis evidenced a high thermal stability for these materials. The X-ray diffractograms displayed crystal facets of WO3 and, when Ni(II) was added, NiWO4. The transmission electron micrographs corroborated the formation of nanosized particles with average particle sizes in the range of 30 to 50 nm. Finally, to apply this material, Pt/WO3-C and Pt/WO3-NiWO4-C were prepared and used in ethanol and glycerol electro-oxidation in an alkaline medium, observing a promotional effect of the oxide and tungstate by reducing the onset potential and increasing the current density. These materials show great potential to produce clean electricity or green hydrogen, contributing to energetic transition.

Eco-friendly synthesis and assessment of chrysin – primed zinc ferrite nanoparticles against vinyl chloride and 2-acetylaminofluorene model of hepatorenal injury in rats

Co-exposure to environmental toxicants is becoming an emerging problem globally. This study investigated the potential of chrysin-primed zinc-ferrite nanoparticles (ZnFe2O4@Chrysin) to counteract oxidative stress and inflammation in vinyl chloride (VC) and 2-acetylaminofluorene (2-AAF) induced liver and kidney toxicities in male Wistar rats. ZnFe2O4@Chrysin was identified using x-ray diffraction, thermogravimetric analysis, Fourier Transform Infrared spectroscopy, scanning and transmission electron micrographs. Molecular orbital distributions in chrysin were determined using Density Functional Theorem analyses. Forty –two rats were placed in six groups of seven animals each, and orally administered with ZnFe2O4@Chrysin (10, 20, 50 mg/kg), VC (50 mg/kg) and 2-AAF (30 mg/kg) over a period of 28 days. Liver and kidney function, lipid profile, oxidative stress, inflammation, endocrine and cancer parameters were evaluated. Treatment with ZnFe2O4@Chrysin ameliorated the VC + 2-AAF induced elevations in alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, triglyceride, urea, uric acid, and sodium and potassium levels. VC + 2-AAF also caused significant elevations in superoxide dismutase, malondialdehyde, nitric oxide, myeloperoxidase levels which were restored by ZnFe2O4@Chrysin. Elevated levels of alpha fetoprotein, C-reactive protein (CRP) and thyroid stimulating hormone in VC + 2-AAF treated rats were significantly reversed by ZnFe2O4@Chrysin. ZnFe2O4@Chrysin also restored the histoarchitecture of the kidney and liver of rats exposed to VC + 2-AAF. This study suggests that ZnFe2O4@Chrysin offered protection against VC and 2-AAF induced alterations in biochemical indices of rats via anti-inflammatory and antioxidant mechanisms.

Fabrication, characterization, and antibacterial activity of ferrite, chromite, and aluminate nanoparticles

Zn0.33Co0.33Mg0.33X2O4 nanoparticles (NPs), where X = Fe, Cr, Al and denoted by F, C, and A, were prepared by the co-precipitation method. X-ray diffraction patterns validated the formation of NPs with cubic spinel structure with the detection of small amounts of impurities in samples C (Cr2O3) and A (MgO). Transmission electron micrographs showed a nearly spherical shape for samples F and A. However, sample C revealed cubic and nearly spherical shapes. Energy-dispersive x-ray analysis ensured the presence of chemical constituents in all samples. The vibrational modes of NPs were confirmed with Fourier transform infrared spectroscopy. The direct bandgap energy values, calculated using ultraviolet-visible spectroscopy, were in the range of 2.355 and 2.967 eV for F, C, and A samples. X-ray photoelectron spectroscopy analysis confirmed the compositions as well as the valence states of all elements. Magnetic hysteresis (M–H) loops revealed a soft ferromagnetic behavior. Sample F exhibited a higher saturation magnetization, remanent magnetization, magnetic moment, and magnetic anisotropy compared to those of samples C and A. The antibacterial activity of the tested samples against four bacteria (Staphylococcus aureus, Stenotrophomonas maltophilia, Escherichia coli, and Enterococcus faecium) was determined using the broth microdilution assay, minimum bactericidal concentration (MBC), and time-kill test. The prepared NPs exhibited varying antibacterial activity due to multiple factors. These results highlighted the potential utility of the ternary ferrite, chromite, and aluminate NPs in the treatment of microbial infections, particularly multidrug-resistant bacteria.

Synthesis of Zinc Oxide Nanoparticles using Extract of Cynodon dactylon and Assessment of their Biological Activity against Staphylococcus aureus and Escherichia coli

Nanotechnology is a groundbreaking technology that that has been widely applied in creating materials which are useful in various fields. It's important to maintain eco-friendly approaches for synthesis of nanoparticles by diversifying the substrate sources. In this study, the researchers used aqueous extract of Cynodon dactylon to synthesize zinc oxide nanoparticles (ZnONPs). Quantitative phytochemical analysis of the extract showed high concentrations of alkaloids, flavonoids, carbohydrates, proteins, amino acids, and phenolic compounds. In contrast, moderate concentrations of tannins, oils, and fats, and low concentrations of phlorotannins, saponin, triterpenoids, and cardiac glycosides were found. Sterols, anthraquinone glycosides, gums, and mucilages were not detected in the extract. The synthesized ZnONPs showed absorbance ranging from 293 nm to 336 nm, with a peak at 307 nm. Fourier transform infrared (FTIR) spectroscopy revealed that the surface of the ZnONPs contained alcohol (intermolecular bonded), alkyne, amine salt, alkane, alkyne, aromatic compounds, conjugated alkene, amine, nitro compound, sulfonyl chloride, alkylaryl ether, and sulfoxide. Dynamic light scatering (DLS) analysis of the ZnONPs showed that its average size was 35.34±1.64 nm, and the polydispersity index was 0.6335. Spectrum of X ray diffraction indicated that peaks formed at 2θ and their corresponding orientation planes are 31.92o (100), 34.62o (002), 36.44o (101), 47.64o (102), 56.84o (110), 63.3o (200), and 68.16o (112). Transmission electron micrograph revealed the spherical shape, and nonuniform sizes of ZnONPs, which ranged from 0.52 nm to 8.32 nm. Antibacterial analysis of biosynthesized ZnONPs recorded 16±3.2 mm and 6.0±2.2 mm; 6.7±2.1 mm and 4.33±1.3 mm, 0.0±0.0 mm and 1.0±1.41 mm, against Staphylococcus aureus and Escherichia coli, at 53.3 mg/mL, 26.7 mg/mL and 13.3 mg/ml concentrations, respectively. At sub-inhibitory concentrations, biosynthesized ZnONPs demonstrated effective dose-dependent antibiofilm formation activity against E. coli and S. aureus. Consequently, extract of Cynodon dactylon is suitable for biosynthesis of ZnONPs with effective antibacterial and antibiofilm formation activities.

The effects of sex hormones on the size of intestinal lipoproteins.

Larger intestinal lipoproteins are more likely to be retained longer in the intestinal wall, allowing more time for their fat to be hydrolyzed and subsequently taken up by the abdominal viscera. Since men generally accumulate more abdominal visceral fat than women, we sought to determine if males produce larger intestinal lipoproteins compared to females. Using the conscious lymph fistula mouse model, we discovered that the male mice indeed produced larger intestinal lipoproteins than the female mice when they were intraduodenally infused with lipid emulsion. We then employed our differentiated Caco-2 cell model with semipermeable membrane system to determine the effects of sex hormones on the size of intestinal lipoproteins. Lipoprotein size was quantitatively measured by calculating the ratio of triglycerides (TG)/Apolipoprotein B (ApoB) and by analyzing their transmission electron micrographs. Our studies showed that while there was no dose-dependent effect of estrogen and progesterone, testosterone significantly increased the size of lipoproteins. When these hormones were combined to resemble the physiological concentrations observed in males and the different ovarian cycle phases in premenopausal females, both the male and luteal groups had significantly larger lipoproteins than the ovulatory group; and the male group also had significantly larger lipoproteins than the follicular group. The ovulatory group secreted a significantly lower amount of TG than the male and luteal groups. ApoB was comparable among all these groups. These findings support our hypothesis that, through their testosterone effects, males are more likely to produce larger intestinal lipoproteins. Larger lipoproteins tend to remain longer in the intestinal wall and may facilitate fat uptake preferentially by the abdominal viscera. Our studies may partly explain why men are more prone to accumulating abdominal visceral fat, which is an independent predictor of mortality.

Ponazuril: Clinical efficacy, ultrastructure, and histopathology studies of in vivo anticoccidial action against Eimeria tenella

Ponazuril, a novel antiprotozoal drug in the class of triazine, has shown a promising application on apicomplexan infections in poultry and livestock. However, the effect and mechanism of action of ponazuril against Eimeria tenella (E. tenella) are unclear. The efficacy against E. tenella was initially studied by administering different doses of ponazuril in drinking water. The treated stage and site of ponazuril on E. tenella were observed through ultrastructural and histopathological analyses. Chicks were orally treated with a dose of 15 mg/kg body weight of ponazuril at different endogenous stages of E. tenella post-infection. According to the clinical study, the values of anticoccidial indices (ACI) were 157.0, 162.3, 196.9, 194.5, and 190.9, respectively, when the ponazuril was administered in drinking water at doses of 5, 10, 20, 40, and 50 mg/L for two consecutive days after infection. Among them, the 20 mg/L ponazuril group showed the best anticoccidial effect, which was superior to that of the toltrazuril treatment group, with an ACI value of 191.7. Histological analysis indicated that ponazuril effectively relieved cecal lesions, and decreased the number of merozoites. Transmission electron micrographs (TEM) observed that merozoites became irregular in shape, and some apparent protrusions of the outer membrane were presented especially the second-generation merozoites. Additionally, abnormalities in the development of WFBI and WFBII in the macrogametocyte were observed, which may affect the formation of the ovule wall. Moreover, merozoites in the treated group showed uneven and marginalized chromatin and mitochondrial swelling. These results suggested ponazuril is a potential anticoccidial drug, providing information on the mechanism of anticoccidial effects.

Comparative effects of chemical and green zinc oxide nanoparticles in caprine testis: ultrastructural and steroidogenic enzyme analysis

ABSTRACT Recent advancements in nanotechnology has opened up enormous possibilities in diverse sectors such as industries, agriculture, environmental remediation, electronics, medicine and varied industries. Among metal oxide nanoparticles zinc oxide nanoparticles has gained considerable attention due to their fascinating physiochemical properties. Rapid growth in the use of zinc oxide nanoparticles (ZnONPs) in daily household products, food and feed additives, biological products, medicine, as antimicrobial agents, electronics and agriculture, creates serious toxic potential risks of these engineered nanoparticles on living organisms. The aim of present study was to assess the effects of synthesized chemical ZnONPs and green ZnONPs on testicular tissue of Capra hircus (goat) in vitro. The reproductive stress was analyzed by ultrastructural damage, change in frequency of apoptotic cells and alteration in steroidogenic enzyme activity. The transmission electron micrographs of testicular cells after treatment with chemical and green ZnONPs at three doses (10 µg/ml, 20 µg/ml and 30 µg/ml) for exposure duration 4 h and 8 h illustrated that chemical nanoparticles induced more alterations, identified as ruptured nuclear membrane, condensation and margination of chromatin material in somatic cells and germ cells in the seminiferous tubules, presence of apoptotic bodies in nucleus of spermatocytes and spermatids, reduction in number of cell organelles, vacuolization and hyalinization of cytoplasm. Maximum damage was observed after treatment of testicular tissues with 30 µg/ml of chemical ZnONPs for 8 h exposure duration. However, the green ZnONPs were found to be less toxic as evidenced by few apoptotic characteristics in testicular cells. The results of fluorescence assay by acridine orange staining showed significant increase in the percentage of apoptotic cells in chemical treated groups as compared to green and control groups. Decreased enzyme activity of 3β-Hydroxysteroid dehydrogenase and 17β-Hydroxysteroid dehydrogenase was assayed in chemical ZnONPs than green ZnONPs treated groups. Our results confirm that chemical ZnONPs are significantly more toxic in comparison to green ZnONPs and adversely affects the male fertility.

Modelling the magnetization data of Fe3O4 nanoparticles above blocking temperature

Nanoparticles of Fe3O4 are prepared by simple co-precipitation method. The sample is characterized using an x-ray diffractometer, transmission electron microscope, and vibrating sample magnetometer. The x-ray diffraction pattern of the sample clearly shows that it is a single-phase magnetite. The transmission electron micrograph shows that the sample has a narrow distribution in particle size with average particle size of 9.9 nm. The SAED pattern only shows the diffraction planes correspond to magnetite and no other phase impurity is detected. The calculated thickness of the magnetic disordered shell due to the reduction in particle size is found to be 1.7 nm. The magnetization of the sample is measured as a function of temperature and applied magnetic field. The zero-field cooled and field cooled curves of the sample are measured in the presence of 250 Oe applied magnetic field and both the curves bifurcate at 170 K. The peak in the zero-field curve indicates that the sample has a blocking temperature of around 100 K. The magnetization as a function of applied magnetic field data at 200, 225, 250, 275 and 300 K are measured (up to ±20 kOe). These magnetization data are used for the fitting to analyze the magnetic behavior of Fe3O4 nanoparticles. . The magnetization of nanoparticles systems is influenced by several factors such as particle size distribution, disordered surface, magnetocrystalline anisotropy, magnetic moment distribution and magnetic interactions. The ignorance of such factors while analyzing the magnetization data leads to discrepancies in the results. The surface effects are sensitive to the reduction in particle size leading to the spin frustrations on the surface suggesting a magnetic disordered layer which affect the magnetic behavior of nanoparticles. This work presents the analysis of the magnetization data in an appropriate magnetization expression which takes into consideration the effect of magnetic moment distribution. This distribution in the magnetic moment is found to be significantly influenced the magnetization analysis and affected by the magnetic disordered surface which accounts for the presence of magnetic anisotropy and magnetic interactions on the particles surface. The results and observations are discussed in detail.

Reactive oxygen species downregulate dystroglycans in the megakaryocytes of rats with arterial hypertension

Hypertension is a multifactorial disease characterized by vascular and renal dysfunction, cardiovascular remodeling, inflammation, and fibrosis, all of which are associated with oxidative stress. We previously demonstrated cellular reactive oxygen species (ROS) imbalances may impact the structural and biochemical functions of blood cells and reported downregulation of β-dystroglycan (β-Dg) and overexpression of the epithelial sodium channel (ENaC) contribute to the pathophysiology of hypertension. In this study, we aimed to determine the expression of dystroglycans (Dg) and ENaC in platelet progenitors (megakaryocytes) and their surrounding niches. Thin sections of bone marrow from 5- and 28-week-old spontaneous hypertensive rats (SHR) were compared to age-matched normotensive rats (WKY). Cytometry and immunohistochemical assays demonstrated an oxidative environment in SHR bone marrow, characterized by high levels of myeloperoxidase and 3-nitrotyrosine and downregulation of peroxiredoxin II. In addition, transmission electron micrography and confocal microscopy revealed morphological changes in platelets and Mgks from SHR rats, including swollen mitochondria. Quantitative qRT-PCR assays confirmed downregulation of Dg mRNA and immunohistochemistry and western-blotting validated low expression of β-Dg, mainly in the phosphorylated form, in Mgks from 28-week-old SHR rats. Moreover, we observed a progressive increase in β-1 integrin expression in Mgks and extracellular matrix proteins in Mgk niches in SHR rats compared to WKY controls. These results indicate accumulation of ROS promotes oxidative stress within the bone marrow environment and detrimentally affects cellular homeostasis in hypertensive individuals.

Isolation, characterization, and application of bacteriophage cocktails for the biocontrol of Pseudomonas fluorescens group strains in whole and skimmed milk.

Pseudomonas fluorescens group strains can lead to spoilage of milk as well as loss of quality in dairy products through their heat-resistant enzymes. Phages are important alternatives for combating spoilage bacteria in food industry and used successfully in many applications. The aim of this study was the isolation and characterization of phages and to assess the efficiency of a phage cocktail in whole and skimmed milk. For this purpose, phages effective against Pseudomonas fluorescens (L23.2), Pseudomonas tolaasii (P22.1), and Pseudomonas rhodesiae (A11.1) were isolated. Their host range was found to be highly specific, and the transmission electron micrographs indicates that they belonged to Tectiviridae family. Their genome sizes were found to be vary between 38.3 and 53.5 kb. The latent periods and burst sizes were determined as 15, 10, 15 min and 91, 20, 80 PFU/infected cell for L23.2, P22.1, and A11.1, respectively. All three phages were found to be sensitive to low pH and high temperature. The effect of the phage cocktail was monitored in milk with different fat contents during storage at 4 °C for 5 days. As a result, bacterial reductions up to 4.09 and 5.29 log-units were observed for the whole and skimmed milk, respectively. Thus, the efficacy of a phage cocktail against a bacterial mixture of different P. fluorescens strains was tested in milk samples with different fat contents in accordance with real-life scenarios for the first time.

Superparamagnetic behavior of non-interacting antiferromagnetic ferritin nanoparticles

Ferritin is an important biological system and found in blood of living organisms. Inorganic cores of this material are 8 nm in size. The cores are surrounded by protein shells which reduce interparticle interaction. Particle size distribution present in ferritin is determined from transmission electron micrograph. This distribution can be described by a log normal distribution function. The magnetic field (0–70 kG) dependence of the magnetization at different temperatures are analyzed considering the estimated particle size distribution. The resulting mean particle magnetic moment is temperature independent and equal to 310 μB. Saturation magnetization and antiferromagnetic susceptibility of ferritin decrease with increasing temperature.

Highly conductive anion-exchange membrane based on poly(acenaphthylenyl aryl piperidinium) π-π self-assembly

The use of strong intermolecular interaction force to promote the formation of ion transport channels is one of the common methods to increase the conductivity of AEMs. In this work, a series of poly(acenaphthylenyl aryl piperidinium) membranes and ionomer were prepared by ultra-strong acid-catalyzed polymerization. The π-π self-assembly of acenaphthylene monomer promoted the aggregation of piperidinium cation and the formation of efficient ion transport channel, which was confirmed by well aggregated transmission electron micrographs of the ion clusters. Therefore, the prepared membrane had desirable conductivity (173.38 mS cm−1 at 80 °C). Meanwhile, the membrane exhibited excellent alkaline stability (99 % retention of conductivity in 3 M NaOH solution immersed at 80 °C for 1000 h), acceptable dimensional stability (swelling rate < 27.78 % at 80 °C), and high mechanical properties (tensile strength >33.9 MPa). The H2/O2 fuel cell assembled based on the prepared QPANTP-20 membrane and ionomer exhibited peak power density of 266 mW cm−2 at 80 °C.