Changes In Ultrastructure Of Cells Research Articles

Comparative study of the ameliorative effects of omega-3 versus selenium on etoposide-induced changes in Sertoli cells and ectoplasmic specialization of adult rat testes: immunohistochemical and electron microscopic study.

Etoposide (Eto) is an anti-cancer drug that is associated with serious adverse effects on male reproductive function. Omega-3 polyunsaturated fatty acids (ω-3 PUFAs) and selenium (Se) are known as anti-inflammatory, anti-apoptotic and anti-oxidant agents. This work was designed to investigate changes in the biochemical parameters as well as alterations in Sertoli cell vimentin expression, ultrastructure and ectoplasmic specializations (ESs) following Eto treatment and to assess the ameliorative effect of ω-3 versus Se on these alterations. Eighty four adult male albino rats were used and classified into four groups: group I (control group), group II (Eto group) received Eto in a single intra-peritoneal (IP) dose (60mg/kg B.W.), group III (Eto & ω-3 group) received the single IP dose of Eto as well as ω-3 (300mg/kg B.W./day by intra-gastric intubation) starting 5days before Eto injection till the time of sacrifice & group IV (Eto & Se group) received the single IP dose of Eto as well as Se (0.5mg/kg B.W./day IP) starting 5days before Eto injection till the time of sacrifice. The rats were subdivided into 2 subgroups (a) and (b) that were sacrificed 3 and 7days after Eto injection respectively. Eto administration in group II induced increase in malondialdehyde (MDA), decrease in superoxide dismutase (SOD), collapse of Sertoli cell vimentin filaments and ultrastructural degenerative changes in both Sertoli cells and ESs. Se (group IV) reversed Eto toxic effects potently, while ω-3 (group III) had some limited protective effects.

Oxymatrine Alleviates Hyperglycemic Cerebral Ischemia/Reperfusion Injury via Protecting Microvessel.

Hyperglycemia aggravates cerebral ischemia/reperfusion (I/R) injury via vascular injury. There is still a lack of effective pharmaceutical preparations for cerebral I/R injury under hyperglycemia. This study aimed to investigate the effects of oxymatrine (OMT) on hyperglycemia-exacerbated cerebral I/R injury in vitro and in vivo. The middle cerebral artery occlusion (MCAO) and reperfusion was established in the rats under hyperglycemia. Meanwhile, oxygen-glucose deprivation and reoxygenation (OGD/R) with high glucose was used as an in vitro model of hyperglycemic cerebral I/R injury. The results showed that the neurological deficit score, mortality, infarct volume and penumbra apoptosis in hyperglycemia group were significantly higher than those in normal glucose group. OMT pre-treated obviously reduced the degree of neurological deficit, mortality, infarct volume, improve cerebral blood flow after I/R in rats with hyperglycemia, and increase the survival rate of human brain microvascular endothelial cells (HBMECs) in high glucose and OGD/R group. OMT significantly improved the ultrastructure changes of endothelial cells, and maintain the migration and angiogenesis potency of HBMECs in high glucose and OGD/R group. OMT obviously alleviated the down-regulating CD31 and CD105 expression in cerebral microvessels caused by hyperglycemia. It is concluded that OMT treatment might alleviate cerebral I/R injury under hyperglycemia via protecting microvessels.

Abstract 12880: Neddylation Regulates Murine Cardiomyocyte Maturation

From birth to adulthood cardiomyocytes (CMs) undergo a complex maturation process characterized by drastic changes in cell size, ultrastructure, metabolism and gene expression. The molecular mechanisms regulating CM maturation remain poorly defined. Neddylation is a novel post-translational modification that covalently attaches a small ubiquitin-like protein, NEDD8, to target proteins. We found that deletion of NAE1, a critical NEDD8 E1 enzyme that triggers neddylation, in embryonic and perinatal mouse hearts via Nkx2.5 Cre and aMHC Cre , respectively, led to myocardial hypoplasia, heart failure and early lethality. The severe cardiac phenotypes are accompanied by disorganized sarcomere structure and defective fetal-to-adult gene transition, suggesting a possible role for neddylation in CM maturation. To rule out the confounding effect of secondary changes caused by perturbed CM differentiation and cardiac stress response in the mutant hearts, we used AAV9-cTnT-Cre to achieve mosaic knockout of NAE1 in postnatal hearts. High-dose AAV9 deleted NAE1 in 80% CMs and caused heart failure, whereas low-dose AVV9 deleted NAE1 in 30% CMs and preserved heart function. In the context of preserved cardiac function, CMs lacking NAE1 showed severe disrupted transverse tubules (T-tubules) network, which was further exacerbated in hearts with modest dysfunction. In contrast, T-tubule morphology was largely maintained in CMs with intact NAE1 expression from low-dose AAV9 infected hearts, as well as in CMs with deletion of one allele of NAE1, indicating a key, cell-autonomous role of neddylation in T-tubule maturation. Biochemical and histological analyses further revealed dysregulated metabolic and sarcomeric gene expression and disrupted sarcomere ultrastructure in high-dose AAV9 infected hearts, supporting defective CM maturation. In vitro, pharmacological inhibition of neddylation also impaired myofibril assembly in isolated neonatal and adult CMs. Together, our data reveal an important role of neddylation in CM maturation in the developing heart, warranting further investigations of detailed posttranslational mechanisms underlying CM maturation.

Comparative cytology combined with transcriptomic and metabolomic analyses of Solanum nigrum L. in response to Cd toxicity

Cadmium (Cd) triggers molecular alterations in plants, perturbs metabolites and damages plant growth. Therefore, understanding the molecular mechanism underlying the Cd tolerance in plants is necessary for assessing the persistent environmental impact of Cd. In this study, Solanum nigrum was selected as the test plant to investigate changes in biomass, Cd translocation, cell ultrastructure, metabolites and genes under hydroponic conditions. The results showed that the plant biomass was significantly decreased under Cd stress, and the plant has a stronger Cd transport capability. Transmission electron microscopy revealed that increased Cd concentration gradually damaged the plant organs (roots, stems and leaves) cell ultrastructure, as evidenced by swollen chloroplasts and deformed cell walls. Additionally, metabolomics analyses revealed that Cd stress mainly affected seven metabolism pathways, including 19 differentially expressed metabolites (DEMs). Moreover, 3908 common differentially expressed genes (DEGs, 1049 upregulated and 2859 downregulated) were identified via RNA-seq among five Cd treatments. Meanwhile, conjoint analysis found several DEGs and DEMs, including laccase, peroxidase, D-fructose, and cellobiose etc., are associated with cell wall biosynthesis, implying the cell wall biosynthesis pathway plays a critical role in Cd detoxification. Our comprehensive investigation using multiple approaches provides a molecular-scale perspective on plant response to Cd stress.

Electron microscopic changes in the nasal membrane of patients with COVID-19 depending on the clinical form and the period of the disease

Given that COVID-19 is a global public health problem and that almost all countries in the world have been severely affected by the COVID-19 pandemic, research is being actively pursued to better understand the effects of the virus on human cells. However, it is not clear what changes are observed in the cells of the main gate of infection – the mucosa of the mouth and the nose at different clinical forms and at different periods of disease. Understanding the ultra-structural cell changes of SARS-CoV-2 targets may help clarify the pathogenic aspects of infection in the lower respiratory tract. In this study, the elements of the life cycle of SARS-CoV-2 virus in the cells of the respiratory epithelium of the nose in patients with COVID-19 were evaluated using electron microscopy for the purpose of detecting the peculiarities of viral activity depending on the form and period of disease. Bioptats of the nasal mucous membrane were taken from COVID-19 patients and subsequently examined by electron microscopy. The severity of structural changes in tissue samples, presence of SARSCoV-2 virus in cells were determined, then bioptats were grouped according to the clinical form of the infection process (inapparent, acute upper respiratory tract infections, viral lung disease) and period of disease. It has been established that the most characteristic changes in the mucous membrane of the nose were observed in the first week of infection caused by SARS-CoV-2 and occurring in the form of acute respiratory disease, while viral lung infections have had the highest virus density in vesicles within cells, the formation of smooth virus-free vesicles is most common in inapparent forms. The data obtained may indicate that the formation of classical virus-induced changes in the respiratory epithelium of the nose mucous (vesicles with viral particles and signs of their release from the cell) is characteristic of localized forms of infection caused by SARS-CoV-2 (respiratory infection of the upper respiratory tract) and in cases of generalized infection (viral infection of the lungs and probably other organs and systems) accumulation of the infectious agent in high concentrations in vesicles.

A traditional Ugandan Ficus natalensis bark cloth exhibits antimicrobial activity against methicillin-resistant Staphylococcus aureus.

Surgical site, soft tissue and wound infections are some of the most prominent causes of healthcare-associated infections (HCAIs). Developing novel antimicrobial textiles and wound dressings may help alleviate the risk of developing HCAIs. We aimed to determine the antimicrobial efficacy of natural Ugandan bark cloth derived exclusively from the Ficus natalensis tree. Antimicrobial contact and disc diffusion assays, coupled with time-kill kinetic assays, demonstrated that bark cloth inhibited the growth of a clinically relevant methicillin-resistant Staphylococcus aureus (MRSA) strain and acted as a bactericidal agent causing a seven-log reduction in bacterial viability. Scanning electron microscopy was used to reveal morphological changes in the bacterial cell ultrastructure when exposed to bark cloth, which supported a proposed mechanism of antimicrobial activity. The observed antimicrobial properties, combined with the physical characteristics elicited by bark cloth, suggest this product is ideally suited for wound and other skin care applications. This is the first report where a whole bark cloth product made by traditional methods has been employed as an antimicrobial fabric against MRSA. Bark cloth is a highly sustainable and renewable product and this study presents a major advance in the search for natural fabrics which could be deployed for healthcare applications.

Ovariectomy Affects Acute Pancreatitis in Mice.

Serum estradiol levels in severe acute injury are correlated with in hospital mortality. In acute pancreatitis, serum estradiol levels are strong predictors of disease severity. Studies of whether changes in estradiol levels play a causative role in acute pancreatitis severity are limited. The ovariectomized mouse model has been used to study the effects of estradiol in health and disease. We assessed whether the ovariectomized mouse model could be used to assess the effects of estradiol on pancreatitis severity. C57BL/6 mice with their ovaries removed were used to simulate low circulating estradiol conditions. Ovariectomized mice were treated with six hourly injections of cerulein to induce mild acute pancreatitis and compared to ovariectomized mice pre-treated with subcutaneous estradiol injections. Findings suggest ovariectomized model is a problematic preparation to study pancreatitis. At baseline, ovariectomy leads to prominent acinar cell ultrastructure changes as well as changes in other select morphologic and biomarkers of pancreatitis. In addition, ovariectomy changed select acute pancreatitis responses that were only partially rescued by estradiol pre-treatment. These findings suggest that the ovariectomized mouse as a model of estradiol depletion should be used with caution in pancreatic studies. Future studies should explore whether derangements in other female hormones produced by the ovaries can lead to changes in pancreatic studies.

Competitive Endogenous RNAs Participate in Benzene Hematotoxicity by Promoting Ferroptosis

Background: Benzene exposure leads to hematotoxicity, but we still lack sensitive biomarkers for its monitoring and prevention owing to the complex mechanisms. We previously constructed a competitive endogenous RNA(ceRNA) regulatory network (Lnc-TC-miR-142-5p-CUL4B), which may be potential biomarkers for benzene hematotoxicity, and further explored the mechanism of these ceRNAs mediating benzene toxicity. Methods: Peripheral hemogram and ceRNA expression were detected in benzene-exposed workers and controls. Cell viability, ultrastructural changes, lipid ROS and expressions of cell ferroptosis related genes GPX4, SLC7A11 and FTH were examined to detect the occurrence of benzene metabolite 1, 4-benzoquinone (1,4-BQ)-induced ferroptosis. Lentiviral transfected cell models of regulating Lnc-TC, miR-142-5p and CUL4B were constructed to explore their regulatory relationships and roles in 1,4-BQ induced ferroptosis. Results: We confirmed that the expression of ceRNAs Lnc-TC-miR-142-5p-CUL4B were significantly changed and associated with decreased blood cell counts in benzene-exposed workers compared with controls. 1,4-BQ promoted cell ferroptosis characterized by mitochondria damages, increased lipid ROS level, and down-regulation of GPX4, SLC7A11 and FTH. Lnc-TC-miR-142-5p-CUL4B ceRNA network regulated 1,4-BQ-induced cell ferroptosis by targeting GPX4, thus participated in benzene hematotoxicity. Conclusion: The Lnc-TC-miR-142-5p-CUL4B ceRNA network mediated benzene hematotoxicity by promoting ferroptosis, and these ceRNAs may be potential biomarkers for early monitoring and warning of disease. Funding Information: This research was supported by the Beijing Natural Science Foundation Program and Scientific Research Key Program of Beijing Municipal Commission of Education (KZ201810025032), the Support Project of High-level Teachers in Beijing Municipal Universities in the Period of 13th Five-year Plan (CIT&TCD20170323) and National Culture Science Foundation of China (81773397). Declaration of Interests: The authors of this article declare that there are no conflicts of interest. Ethics Approval Statement: The study was approved by Ethics committee of Capital Medical University, each individual signed an informed consent form.

Puerarin Restores Autophagosome-Lysosome Fusion to Alleviate Cadmium-Induced Autophagy Blockade via Restoring the Expression of Rab7 in Hepatocytes.

Autophagic dysfunction is one of the main mechanisms by which the environmental pollutant cadmium (Cd) induces cell injury. Puerarin (Pue, a monomeric Chinese herbal medicine extract) has been reported to alleviate Cd-induced cell injury by regulating autophagy pathways; however, its detailed mechanisms are unclear. In the present study, to investigate the detailed mechanisms by which Pue targets autophagy to alleviate Cd hepatotoxicity, alpha mouse liver 12 (AML12) cells were used to construct a model of Cd-induced hepatocyte injury in vitro. First, the protective effect of Pue on Cd-induced cell injury was confirmed by changes in cell proliferation, cell morphology, and cell ultrastructure. Next, we found that Pue activated autophagy and mitigated Cd-induced autophagy blockade. In this process, the lysosome was further activated and the lysosomal degradation capacity was strengthened. We also found that Pue restored the autophagosome-lysosome fusion and the expression of Rab7 in Cd-exposed hepatocytes. However, the fusion of autophagosomes with lysosomes and autophagic flux were inhibited after knocking down Rab7, and were further inhibited after combined treatment with Cd. In addition, after knocking down Rab7, the protective effects of Pue on restoring autophagosome-lysosome fusion and alleviating autophagy blockade in Cd-exposed cells were inhibited. In conclusion, Pue-mediated alleviation of Cd-induced hepatocyte injury was related to the activation of autophagy and the alleviation of autophagy blockade. Pue also restored the fusion of autophagosomes and lysosomes by restoring the protein expression of Rab7, thereby alleviating Cd-induced autophagy blockade in hepatocytes.

Curcumin induces ferroptosis in non-small-cell lung cancer via activating autophagy.

BackgroundEmerging studies showed curcumin can inhibit glioblastoma and breast cancer cells via regulating ferroptosis. However, the role of ferroptosis in the inhibitory effect of curcumin on non‐small‐cell lung cancer (NSCLC) remains unclear.MethodsCell counting kit‐8 (CCK‐8) assay was used to measure the viability of A549 and H1299 cells under different conditions. Cell proliferation was examined by Ki67 immunofluorescence. The morphological changes of cells and tumor tissues were observed by optical microscope and hematoxylin and eosin (H&E) staining. Intracellular reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH), and iron contents were determined by corresponding assay kit. The related protein expression levels were detected by western blot and immunohistochemistry. Transmission electron microscope was used to observe ultrastructure changes of A549 and H1299 cells.ResultsCurcumin inhibited tumor growth and cell proliferation, but promoted cell death. Characteristic changes of ferroptosis were observed in curcumin group, including iron overload, GSH depletion and lipid peroxidation. Meanwhile, the protein level of ACSL4 was higher and the levels of SLC7A11 and GPX4 were lower in curcumin group than that in control group. Incubation of ferroptosis inhibitors ferrostatin‐1 (Fer‐1) or knockdown of iron‐responsive element‐binding protein 2 (IREB2) notably weakened curcumin‐induced anti‐tumor effect and ferroptosis in A549 and H1299 cells. Further investigation suggested that curcumin induced mitochondrial membrane rupture and mitochondrial cristae decrease, increased autolysosome, increased the level of Beclin1 and LC3, and decreased the level of P62. Curcumin‐induced autophagy and subsequent ferroptosis were both alleviated with autophagy inhibitor chloroquine (CQ) or siBeclin1.ConclusionCurcumin induced ferroptosis via activating autophagy in NSCLC, which enhanced the therapeutic effect of NSCLC.

The photothermal effect of polypyrrole modified gold nanoparticles on SKOV-3 cells using SEM and AFM

Nanotechnology and its application are widely used in the field of life, human exploration of life science has entered the nano level, which is of great significance for exploring the essence of cellular life. This paper explores the changes in the mechanical characteristics of tumor cells after the photothermal effect of nanomaterials. The experiments used AFM and SEM to measure and observe SKOV-3 cells before and after the treatment. It was found that the cell height, morphology, cell adhesion, and Young’s modulus had significantly changed. In the PPy-GNPs+Laser group, the adhesion force value was 3.57±1.25 nN, and Young’s modulus was 27.4±2.47 kPa. From the data, a 53.9% increase in Yong’s modulus of laser test PPy-GNPs as compared with the control group. It shows that the photothermal effect of nanoparticles has an important effect on the changes of cell ultrastructure, which has important significance for explaining the changes of cell physiological functions from the perspective of cell mechanics.

Protective effect of chondroitin sulfate nano-selenium on chondrocyte of patients with Kashin-Beck disease.

To investigate the protective effect of chondroitin sulfate nano-selenium (SeCS) on chondrocyte of Kashin-Beck disease (KBD). Chondrocyte samples were isolated from the cartilage of three male KBD patients (54-57 years old). The chondrocytes were respectively divided into four groups: (a) control group, (b) SeCS supplement group (100 ng/mL SeCS), (c) T-2 + SeCS supplement group (20 ng/mL T-2 + 100 ng/mL SeCS), and (d) T-2 group (20 ng/mL T-2). Live/dead staining and transmission electron microscopy (TEM) were used to observe cell viability and ultrastructural changes in chondrocytes respectively. Expressions of Caspase-9, cytochrome C (Cyt-C), and chondroitin sulfate (CS) structure-modifying sulfotransferases including carbohydrate sulfotransferase 3, 15 (CHST-3, CHST-15), and uronyl 2-O-sulfotransferase (UST) were examined by quantitative real-time polymerase chain reaction. After one- or three-days intervention, the number of living chondrocytes in the SeCS supplement group was higher than that in the control group, while it is opposite in the T-2 + SeCS supplement group and T-2 group. The cellular villi number in the surface increased in the SeCS supplement group compared with the control group. Mitochondrial morphology density was improved in the T-2 + SeCS supplement group compared with the T-2 group. Expressions of CHST-3, CHST-15, UST, Caspase-9, and Cyt-C on the mRNA level significantly increased in the T-2 + SeCS supplement group and T-2 group compared with the control group. SeCS supplement increased the number of living chondrocytes, improved the ultrastructure, and altered the expressions of CS structure-modifying sulfotransferases, Caspase-9, and Cyt-C.

Lipidome Remodeling and Autophagic Respose in the Arachidonic-Acid-Rich Microalga Lobosphaera incisa Under Nitrogen and Phosphorous Deprivation

The green microalga Lobosphaera incisa accumulates triacylglycerols (TAGs) with exceptionally high levels of long-chain polyunsaturated fatty acid (LC-PUFA) arachidonic acid (ARA) under nitrogen (N) deprivation. Phosphorous (P) deprivation induces milder changes in fatty acid composition, cell ultrastructure, and growth performance. We hypothesized that the resource-demanding biosynthesis and sequestration of ARA-rich TAG in lipid droplets (LDs) are associated with the enhancement of catabolic processes, including membrane lipid turnover and autophagic activity. Although this work focuses mainly on N deprivation, a comparative analysis of N and P deprivation responses is included. The results of lipidomic profiling showed a differential impact of N and P deprivation on the reorganization of glycerolipids. The formation of TAG under N deprivation was associated with the enhanced breakdown of chloroplast glycerolipids and the formation of lyso-lipids. N-deprived cells displayed a profound reorganization of cell ultrastructure, including internalization of cellular material into autophagic vacuoles, concomitant with the formation of LDs, while P-deprived cells showed better cellular ultrastructural integrity. The expression of the hallmark autophagy protein ATG8 and the major lipid droplet protein (MLDP) genes were coordinately upregulated, but to different extents under either N or P deprivation. The expression of the Δ5-desaturase gene, involved in the final step of ARA biosynthesis, was coordinated with ATG8 and MLDP, exclusively under N deprivation. Concanamycin A, the inhibitor of vacuolar proteolysis and autophagic flux, suppressed growth and enhanced levels of ATG8 and TAG in N-replete cells. The proportions of ARA in TAG decreased with a concomitant increase in oleic acid under both N-replete and N-deprived conditions. The photosynthetic apparatus’s recovery from N deprivation was impaired in the presence of the inhibitor, along with the delayed LD degradation. The GFP-ATG8 processing assay showed the release of free GFP in N-replete and N-deprived cells, supporting the existence of autophagic flux. This study provides the first insight into the homeostatic role of autophagy in L. incisa and points to a possible metabolic link between autophagy and ARA-rich TAG biosynthesis.

TrkB-Targeted Therapy for Mucoepidermoid Carcinoma.

The brain-derived neurotrophic factor (BDNF)/tyrosine receptor kinase B (TrkB) pathway was previously associated with key oncogenic outcomes in a number of adenocarcinomas. The aim of our study was to determine the role of this pathway in mucoepidermoid carcinoma (MEC). Three MEC cell lines (UM-HMC-2, H253 and H292) were exposed to Cisplatin, the TrkB inhibitor, ANA-12 and a combination of these drugs. Ultrastructural changes were assessed through transmission electron microscopy; scratch and Transwell assays were used to assess migration and invasion; and a clonogenic assay and spheroid-forming assay allowed assessment of survival and percentage of cancer stem cells (CSC). Changes in cell ultrastructure demonstrated Cisplatin cytotoxicity, while the effects of ANA-12 were less pronounced. Both drugs, used individually and in combination, delayed MEC cell migration, invasion and survival. ANA-12 significantly reduced the number of CSC, but the Cisplatin effect was greater, almost eliminating this cell population in all MEC cell lines. Interestingly, the spheroid forming capacity recovered, following the combination therapy, as compared to Cisplatin alone. Our studies allowed us to conclude that the TrkB inhibition, efficiently impaired MEC cell migration, invasion and survival in vitro, however, the decrease in CSC number, following the combined treatment of ANA-12 and Cisplatin, was less than that seen with Cisplatin alone; this represents a limiting factor.

Physiological and structural responses of the seagrassCymodocea nodosato titanium dioxide nanoparticle exposure

AbstractThe extensive application of titanium dioxide nanoparticles (TiO2NPs) has raised concern about its environmental risks. The present study aims to elucidate TiO2NP ecotoxicity, by assessing effects on seagrasses at environmentally relevant concentrations. Changes in physiological and structural cell traits ofCymodocea nodosaleaves, treated with TiO2NPs at 0.0015–1.5 mg l−1for eight consecutive days, were investigated. Intracellular levels of hydrogen peroxide (H2O2) increased significantly, even early during the lowest exposure, despite an up-regulation of H2O2-scavenging enzyme activity. Actin filaments (AFs) and endoplasmic reticulum (ER) were affected in a concentration- and time-dependent pattern, while no changes in microtubule organization and cell ultrastructure were detected. The lowest effect concentrations for AF and ER impairment were 0.15 and 1.5 mg l−1, respectively; for cell death, these were 0.15–1.5 mg l−1, depending on leaf age, and for leaf elongation inhibition 0.15 mg l−1. Thus, elevated H2O2level can be considered as an early warning biomarker for TiO2NPs, while leaf elongation, AF and ER impairment are also reliable indicators. A risk quotient greater than 1 was estimated; thus, TiO2NPs might present a significant potential environmental risk. Our findings can be utilized for monitoring pollution levels in coastal environments.

Study amino acid contents, plant growth variables and cell ultrastructural changes induced by cadmium stress between two contrasting cadmium accumulating cultivars of Brassica rapa ssp. chinensis L. (pak choi).

Cadmium (Cd) is an inauspicious abiotic traction that not only influences crop productivity and its growth parameters, but also has adverse effects on human health if these crops are consumed. Among crops, leafy vegetables which are the good source of mineral and vitamins accumulate more Cd than other vegetables. It is thus important to study photosynthetic variables, amino acid composition, and ultrastructural localization of Cd differences in response to Cd accumulation between two low and high Cd accumulating Brassica rapa ssp. chinensis L. (pak choi) cultivars, differing in Cd accumulation ability. Elevated Cd concentrations significantly lowered plant growth rate, biomass, leaf gas exchange and concentrations of amino acids collated to respective controls of both cultivars. Electron microscopy indicated that the impact of high Cd level on ultrastructure of leaf cells was associated to affecting cell functionalities, i.e. irregular cell wall, withdrawal of cell membrane, and chloroplast structure which has negative impact on photosynthetic activities, thus causing considerable plant growth suppression. Damage in root cells were observed in the form of enlargement of vacuole. The energy dispersive micro X-ray spectroscopy of both cultivars leaves indicated that cellular structure exhibited exudates of Cd-dense material. Ultrastructural damages and phytotoxicity were more pronounced in high accumulator cultivar as compared to the low accumulator cultivar. These findings are useful in determining the mechanisms of differential Cd-tolerance among cultivars with different Cd tolerance abilities at cellular level.

Investigation of the toxic effects of different polystyrene micro-and nanoplastics on microalgae Chlorella vulgaris by analysis of cell viability, pigment content, oxidative stress and ultrastructural changes

Plastics of different sizes (micro- and nano-sized) are often identified in aquatic environments. Nevertheless, their influence on marine organisms has not been widely investigated. In this study, the responses of the microalga Chlorella vulgaris to micro- and nanoplastics exposure were examined using long term toxicity test. The plastics tested were carboxyl-functionalized and non-functionalized polystyrene of 20, 50 and 500 nm in diameter. A reduction in algal cell viability and chlorophyll a concentration has been observed after exposure to the small sizes (20 and 50 nm) of plastics. Lactate dehydrogenase activity and reactive oxygen species concentration/production were significantly higher after exposure to the 20 nm nanoplastics than that of control confirming the stress condition. Fourier transform infrared (FTIR) spectroscopy analysis proved the attachment of nanoplastics to microalgae and rearrangement of extracellular polymeric substances. The cellular stress appeared as increased cell size, deformed cell wall and increased volume of starch grains.

Erythropoietin and Mesenchymal Stem Cells Properties

The present work reports the effect of the long-term exposure bone marrow mesenchymal stem cells from chronic ischemic heart disease patients with erythropoietin on morpho-functional properties. The mesenchymal stem cells were grown under 3rd passage in medium supplemented with 33.4 IU/mL of recormon to study expression of adhesion molecules, erythropoietin receptor, cytokine receptor to common β-chain on surface, and proliferative potential (MTT test, CFU, cell cycle), migratory ability, nitric oxide production under growth factor deprivation, oxidative stress and hyperglycemia conditions, and autophagy activity, and ultrastructure changes in cells. The results showed that the long-term exposure mesenchymal stem cells with erythropoietin significantly increased proliferation, nitric oxide production and some adhesion molecules and receptors expression on surface of those cells. In addition, the erythropoietin long-term exposure with mesenchymal stem cells increases autophagy activity. The finding of this work indicates that erythropoietin could be used to augment cell resistance to adverse microenvironment condition.

Effect and mechanism of PI3K/AKT/mTOR signaling pathway in the apoptosis of GC-1 cells induced by nickel nanoparticles

Nickel nanoparticles (Ni NPs) have a wide range of application prospects, but there is still a lack of their safety evaluation for the reproductive system. Nowadays, male reproductive health has been widely concerned because of the increasing incidence of male infertility. Studies have shown that Ni NPs can cause male reproductive toxicity. The purpose of this study was to investigate the toxicity of Ni NPs on GC-1 cells, a mouse spermatogonia cell line, and to explore the possible mechanism underlying the induction of apoptosis via PI3K/AKT/mTOR signaling pathway. The cell ultrastructure was firstly observed under a transmission electron microscope. Then, cell proliferation, cycle and apoptosis were detected by CCK-8 and flow cytometry, respectively. Furthermore, the expression levels of related proteins and genes were determined by Western blot and Reverse transcription-polymerase chain reaction, respectively. The results showed that Ni NPs could not only cause changes in cell ultrastructure, decreased survival rate and arrested G1 phase cell cycle, but also activated apoptosis pathway by inhibiting the PI3K/AKT/mTOR signaling pathway. The results of this study provide novel insights to explore the mechanisms of reproductive toxicity of Ni NPs and are of great significance to develop safety evaluation criteria for Ni NPs.

Mannosylerythritol lipids: dual inhibitory modes against Staphylococcus aureus through membrane-mediated apoptosis and biofilm disruption

Mannosylerythritol lipids (MELs) are novel biosurfactants performing excellent physical-chemical properties as well as bioactivities. This study is aimed to explore the antibacterial and antibiofilm activity of mannosylerythritol lipids against foodborne gram-positive Staphylococcus aureus. The results of growth curve and survival rate revealed the significant inhibitory effect of MELs against S. aureus. The visualized pictures by scanning electron microscope and transmission electron microscope exposed apparent morphological and ultrastructure changes of MEL-treated cells. Furthermore, flow cytometry confirmed that MELs have promoted cell apoptosis and damaged the cell membrane. Notably, MEL-A also exhibited outstanding antibiofilm activity against S. aureus biofilm on different material surfaces including polystyrene, glass, and stainless steel, verified by confocal laser scanning microscope. These findings suggest that the antimicrobial activity of MELs is related to inhibit planktonic cells and biofilm of S. aureus, indicating that it has potential to be an alternative to antibacterial agents and preservatives applied into food processing.Key Points • MELs have strong antibacterial activity against Staphylococcus aureus.• MELs mainly damage the cell membrane of Staphylococcus aureus.• Mannosylerythritol lipids inhibit the bacterial adhesion to remove biofilm.