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Abstract This study compares the effects of virus-cell interactions among SARS-CoV-2 variants of concern (VOCs) isolated in Brazil in 2021, hypothesizing a correlation between cellular alterations and mortality and between viral load and transmissibility. For this purpose, reference isolates of Alpha, Gamma, Zeta, and Delta variants were inoculated into monolayers of Vero-E6 cells. Viral RNA was quantified in cell supernatants by RT‒PCR, and infected cells were analyzed by Transmission Electron Microscopy (TEM) for qualitative and quantitative evaluation of cellular changes 24, 48, and 72 hours postinfection (hpi). Ultrastructural analyses showed that all variants of SARS-CoV-2 altered the structure and function of mitochondria, nucleus, and rough endoplasmic reticulum of cells. Monolayers infected with the Delta variant showed the highest number of modified cells and the greatest statistically significant differences compared to those of other variants. Viral particles were observed in the cytosol and the cell membrane in 100 % of the cells at 48 hpi. Alpha showed the highest mean particle diameter (79 nm), and Gamma and Delta were the smallest (75 nm). Alpha and Gamma had the highest particle frequency per field at 48 hpi, while the same was observed for Zeta and Delta at 72 hpi and 24 hpi, respectively. The cycle threshold of viral RNA varied among the target protein, VOC, and time of infection. The findings presented here demonstrate that all four VOCs evaluated caused ultrastructural changes in Vero-E6 cells, which were more prominent when infection occured with the Delta variant.
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SUMMARY: In this study we describe the functional morphology of Cornu aspersum (Helix aspersa), spermatozoa using light, scanning (SEM) and transmission electron (TEM) microscopies. The studies were performed with sperm located in the frozen hermaphroditic duct. Our results showed that the head presents an elongated conical shape slightly coiled in a corkscrew, with the nucleus partially covered by an acrosome, where an apical vesicle is located at the lateralized apex. This peculiar shape suggests the helical displacement movement of the spermatozoa. The head and the nucleus are slightly larger size compared to those of other gastropod species. The intermediate tract is surrounded by a mitochondrial complex and a glycogen helix. The glycogen helix is coiled helically along the intermediate tract, presenting at least five twists of glycogen helices. The complexity of both the mitochondrial complex and the glycogen helix suggests a high metabolic consumption considering the long period of time until fertilization occurs. Our findings on the detailed characterization of Cornu aspersum spermatozoa, obtained from a frozen hermaphroditic duct can contribute to a better understanding of the functional morphology of sperm and serve as a reference for future studies.
En este estudio describimos la morfología funcional de Cornu aspersum (Helix aspersa), espermatozoides utilizando microscopías de luz, barrido (SEM) y electrónica de transmisión (TEM). Los estudios se realizaron con espermatozoides localizados en el conducto hermafrodita congelado. Nuestros resultados mostraron que la cabeza presenta una forma cónica alargada ligeramente enrollada en un tirabuzón, con el núcleo parcialmente cubierto por un acrosoma, donde se ubica una vesícula apical en el ápice lateralizado. Esta peculiar forma sugiere el movimiento de desplazamiento helicoidal de los espermatozoides. La cabeza y el núcleo son de un tamaño ligeramente mayor en comparación con los de otras especies de gasterópodos. El tracto intermedio está rodeado por un complejo mitocondrial y una hélice de glucógeno. La hélice de glucógeno se enrolla helicoidalmente a lo largo del tracto intermedio, presentando al menos cinco giros de hélices de glucógeno. La complejidad tanto del complejo mitocondrial como de la hélice de glucógeno sugiere un alto consumo metabólico considerando el largo período de tiempo hasta que ocurre la fecundación. Nuestros hallazgos sobre la caracterización detallada de los espermatozoides de Cornu aspersum, obtenidos de un conducto hermafrodita congelado, pueden contribuir a una mejor comprensión de la morfología funcional de los espermatozoides y servir como referencia para futuros estudios.
Subject(s)
Animals , Snails , Spermatozoa/ultrastructure , Spermatozoa/physiology , Microscopy, Electron, Scanning , Cryopreservation , Microscopy, Electron, Transmission , Hermaphroditic OrganismsABSTRACT
Abstract Intratumoral similarities and differences between large-cell neuroendocrine carcinomas (LCNECs) and small-cell lung carcinomas (SCLCs) are determined partially by the Notch signaling pathway, which controls the switch from neuroendocrine to slight/non-neuroendocrine cell fate. LCNECs are divided into two subgroups according to genomic alterations: type I LCNECs exhibit a neuroendocrine profile characterized by achaete‐scute homolog 1 (ASCL1)high/delta-like protein 3 (DLL3)high/NOTCHlow and type II LCNECs show the pattern ASCL1low/DLL3low/NOTCHhigh. Here, we used immunohistochemistry, transmission electron microscopy, and digital analysis to examine the role of the Notch ligand DLL3 as an immunomarker of the neuroendocrine state and ASCL1 as a regulator of cell-cell interactions in SCLCs and LCNECs. High DLL3 and ASCL1 expression was associated with atypical submicroscopic characteristics involving nuclear size, chromatin arrangement, Golgi apparatus, and endoplasmic reticulum, and was characteristic of type I LCNECs with similarity to SCLCs, whereas low DLL3 and ASCL1 expression was found in both SCLCs and type II LCNECs. In patients diagnosed at an early stage who did not have metastasis and who underwent chemotherapy, DLL3high and ASCL1high SCLCs and type I LCNECs were associated with a better prognosis and a lower risk of death. The present findings suggested that DLL3/ASCL1 are potential therapeutic targets and prognostic indicators in patients with SCLCs or LCNECs.
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BACKGROUND According to the last 2023 Monkeypox (Mpox) Outbreak Global Map from the Centres for Disease Control and Prevention (CDC), more than 100 countries with no Mpox infection report cases. Brazil stands out in this group and is the second country with the highest number of cases in the last outbreak. OBJECTIVE To contribute to knowledge of the virus infection effects in a cellular model, which is important for diagnosis infections not yet included in a provider´s differential diagnosis and for developing viral inhibition strategies. METHODS We describe a virus isolation protocol for a human clinical sample from a patient from Brazil, the viral growth in a cell model through plaque forming units (PFU) assay, reverse transcriptase polymerase chain reaction (RT-PCR) and transmission electron microscopy (TEM). FINDINGS We follow the viral isolation in Vero cell culture from a Mpox positive clinically diagnosed sample and show the infection effects on cellular structures using a TEM. MAIN CONCLUSIONS Understanding the impact of viral growth on cellular structures and its replication kinetics may offer better strategies for the development of new drugs with antiviral properties.
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Introduction: Cytopathology is a collection method that allows cell analysis through the different techniques. The oral mucosa exfoliated cells observation demonstrates morphological, biochemical and/or molecular aspects depending on the type of processing of the sample. Aim: This study tested the use of oral cytopathology associated with transmission electron microscopy (TEM) to observe the morphology of cells, mainly in relation to the cell nucleus, the cytoplasmic membrane, and cell junctions. Materials and Methods: Exfoliated epithelial cells from the oral mucosa were analyzed by TEM from individuals exposed to tobacco and alcohol, with leukoplakia or with a histopathological diagnosis of squamous cell carci-noma. Results: The cytoplasmic cell-cell junctions in the malignant samples lost the characteristic irregular pattern formed by the numerous interdigitations and the junctional process of normal cells and started to present a straight cytoplasmic surface. The nuclei of cells from leukoplakia and squamous cell carcinoma samples showed heterogeneous staining, while non-lesional cells were homogeneous. Discussion: The analysis of oral cytopathological smears by TEM contributes to the un-derstanding of the changes that occur during the process of malignancy of the oral mucosa, especially with regard to the cytoplasmic membrane and intercellular junctions. Conclusion: TEM may be a good analytical method to investigate morphological changes in exfoliated cells of the oral epithelium.
Introdução: A citopatologia é um método de coleta que permite a análise celular por meio de diferentes técnicas. A observação das células esfoliadas da mucosa bucal demonstra aspectos morfológicos, bioquímicos e/ou moleculares dependendo do tipo do processamento empregado. Objetivo: Este estudo testou o emprego da técnica de citopatologia bucal associada à microscopia eletrônica de transmissão (MET) para observar a morfologia das células, principalmente com relação à membrana citoplasmática, as junções celulares e ao núcleo da célula. Materiais eMétodos: Células epiteliais esfoliadas da mucosa bucal foram analisadas por MET de indivíduos expostos a tabaco e álcool, apresentando leucoplasia ou com diagnóstico de carcinoma espinocelular. Resultados:As junções citoplasmáticas célula-célula nas amostras malignas perderam o padrão irregular característico formado pelas inúmeras interdigitações e o processo juncional das células normais e passaram a apresentar uma superfície citoplasmática reta. O núcleo das células das amostras de leucoplasia e do carcinoma espinocelular apresentou coloração heterogênea, enquanto as células não lesionais foram homogêneas. Discussão: A análise de esfregaços citopatológicos bucais por MET contribui para o entendimento das alterações que ocorrem durante o processo de malignidade da mucosa bucal, principal-mente no que diz respeito à membrana citoplasmática e as junções intercelulares. Conclusão: A MET pode ser um bom método analítico para investigar alterações morfológicas em células esfoliadas do epitélio bucal.
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Landfills are considered the main option for dumping of municipal solid waste (MSW) all over the world, but these landfills are mostly non-engineered. The decomposition of solid waste in the landfill and rainwater penetration into the decomposing waste produces leachate that contains dissolved organic and inorganic compounds, heavy metals, suspended particles, and hazardous substances. Leachate migration in the environment may pose serious health risks to organisms exposed. Hence, the present study explored the cytotoxic potential of landfill leachate collected in different seasons from the Okhla landfill site, Delhi, India. Cytotoxicity of leachate samples was evaluatedby cell apoptosis and ultrastructural observation based on Transmission Electron Microscopy (TEM) of the cells of root tips of vicia faba seedlings treated with the leachates collected in summer, winter and monsoon in a time and dose dependent manner. Leachate collected in all the three seasons induced apoptosis in cells of root tips of vicia faba that increased in a time and dose dependent manner when compared to control. The apoptosis was highest in the samples treated with leachate collected in the summer season, followed by winter and monsoon. It was further confirmed with TEM images that there was induction of apoptotic-like morphological changes in the root cells treated with landfill leachate when compared with the control. The present study indicates that municipal solid waste leachate is very toxic and it should be treated before disposing it to the environment.
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Abstract Background: Little is known about the ultrastructure of pili annulati. Objectives: To examine with transmission electron microscopy affected hairs of a family, whose diagnosis had been confirmed in five individuals with scanning electron microscopy, which showed surface undulations with ''curtain-like'' folding of the hair cuticula and to compare the findings with normal control. Methods: Hairs of two affected patients and one control were embedded in resin and cut lengthwise to produce ultra-thin sections. Results: The normal hair showed a parallel arrangement of dark lines associated with less electron-dense wide bands. Small cavities could be observed, mostly in the dark lines, affected hairs had a large number of cavities, associated or not with the insertion of melanosomes and loss of parallelism of the dark lines. Higher magnification showed a significant loss of this parallelism, resembling ''wood grooves''. Widened dark lines were observed in some areas. Study limitations: Only a few hairs were examined. Conclusions: The present results suggest that the microcanaliculi of the hair surface, easily found with scanning electron microscopy, may be secondary not only to the cavities seen in the sections but also to the disorder of proteins that form this region, demonstrated by the changes of the cortex dark lines.
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The indicators for structural analysis of blood formed elements are prominent in the assessment of pathologies, diagnostics and the degree. Therefore, we aimed to evaluate the ongoing alterations that reflect on the structural characteristics of blood formed elements based on the hormonal imbalance among menopausal women with uterine tumors. Blood samples from the women with benign (n=20), malignant (n=20) uterine tumors, and healthy menopausal women (control, n=20) were used. Enzyme-linked Immunosorbent assay (ELISA) kits were used for the quantitative determination of hormones. The blood formed elements ultrastructure observations were conducted using transmission electron microscope. Compared to control (33.8±0.7 pg/mL), estradiol level was higher in benign (45.7±0.9 pg/mL) and malignant (70.7±3.7 pg/mL) cases (P< 0.001). Similar pattern was noted in testosterone levels [control=0.38±0.03 ng/mL, benign=0.55±0.04 ng/mL (P< 0.01), malignant=1.56±0.14 ng/mL (P< 0.001)] was higher in malignant cases. In contrast, progesterone levels were decreased in the disease cases [control=0.93±0.05 ng/mL, benign=0.44±0.003 ng/mL, malignant=0.31±0.02 ng/ml (P< 0.001)]. Assessments of the morphologic structure of erythrocytes revealed pathological forms of erythrocytes (poikilocytosis) in case of benign, as well as in malignant tumors. particularly target cells (codocytes), hamlet cells, teardrop cells (dacrocytes), sickle cell (drepanocytes) erythrocytes. Using ELISA and transmission electron microscopy our results demonstrate that in case of malignant uterine tumor quantitative/structural changes occur in blood formed elements indicating ongoing alterations in hormonal imbalance. Assessing these changes in structural characteristics would be useful in examining uterine pathologies and subsequent treatment plans
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ABSTRACT Introduction: Improved long-term patency of the no-touch (NT) saphenous vein graft has been reported to result from the preservation of a healthy vascular microstructure, especially endothelial cells. However, the precise morphology of endothelial cells and their organelles in NT saphenous vein graft has not been fully investigated. In this study, we assessed the ultrastructure of preserved endothelial cells in saphenous vein graft using transmission electron microscopy. Methods: Intact control (IC) vein, NT saphenous vein graft, and conventional (CT) saphenous vein graft were harvested from a patient. After observation by light microscopy, the nuclei and mitochondria in the preserved endothelial cells were compared among IC, NT, and CT using transmission electron microscopy, and the endothelial organelles were assessed quantitatively. Results: Light microscopy showed that the preservation of endothelial cells was comparable in IC, NT, and CT. Subsequent transmission electron microscopy observation showed that the nuclei in preserved endothelial cells appeared more swollen in CT than that in NT. Quantitative analysis revealed that nuclear size and circularity of preserved endothelial cells in NT and IC were similar, but those in CT were larger and higher, respectively, than those in IC and NT. In addition, the mitochondrial size in preserved endothelial cells in CT was larger than that in IC and NT. Conclusion: Necrotic changes in endothelial organelles characterized by swelling of nuclei and mitochondria were prominent in CT saphenous vein graft. The normally maintained ultrastructure of preserved endothelial cells in NT saphenous vein graft could contribute to long-term patency.
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Neurofibromatosis (NF) is a genetic disease in which the lungs are rarely involved. However, in NF cases with lung involvement, chest computed tomography may show bilateral basal reticulations, apical bullae, and cysts without bronchiectasis. Herein, we report a patient diagnosed with NF on the basis of the results of genetic testing who presented with early-onset wet cough and bronchiectasis. Considering the differential diagnosis of bronchiectasis combined with his early-onset wet cough, sinusitis, and sperm quality decline, we considered the possibility of primary ciliary dyskinesia (PCD). Further electron microscopy analysis of cilia and identification of homozygous mutations in the RSPH4A gene confirmed the diagnosis of PCD. Therefore, for patients with NF, when an image change exists in the lungs that does not correspond to NF, the possibility of other diagnoses, including PCD, must be considered.
Subject(s)
Humans , Cilia , Kartagener Syndrome/genetics , Microscopy, Electron , Mutation , Neurofibromatosis 1/geneticsABSTRACT
The habanero chilli pepper, Capsicum chinense is an important crop in the Amazon Basin, mainly grown by small-scale producers. Capsicum chinense plants in an experimental field in the northern Brazilian state of Amazonas were found exhibiting characteristic symptoms of viral infection. Leaf sap from symptomatic plants examined under a transmission electron microscope revealed the presence of elongated flexuous particles and isometric particles. Using molecular assays, the viruses were identified as pepper yellow mosaic virus (PepYMV) and cucumber mosaic virus (CMV). Aphids, identified as Aphis gossypii, were found colonizing the C. chinense plants in the field and may be the vector for both PepYMV and CMV. We report the first occurrence of these viruses infecting C. chinense in the state of Amazonas.
A pimenta-de-cheiro, Capsicum chinense é uma cultura importante na Bacia Amazônica, cultivada principalmente por pequenos produtores. Plantas de C. chinense em um campo experimental localizado no norte do estado brasileiro do Amazonas, foram encontradas apresentando sintomas característicos de infecção viral. Extratos de amostras de folhas sintomáticas examinados ao microscópio eletrônico de transmissão revelaram a presença de partículas alongadas e flexuosas e de partículas isométricas. Análises moleculares permitiram identificar a presença do pepper yellow mosaic virus (PepYMV) e do cucumber mosaic virus (CMV). Pulgões, identificados como Aphis gossypii foram encontrados colonizando pimenteiras-de-cheiro neste campo experimental e podem representar o provável vetor de PepYMV e CMV. Este trabalho relata a primeira ocorrência desses vírus infectando C. chinense no estado do Amazonas.
Subject(s)
Capsicum/virology , Cucumovirus/pathogenicity , Microscopy, Electron, Transmission/instrumentation , Polymerase Chain ReactionABSTRACT
The habanero chilli pepper, Capsicum chinense is an important crop in the Amazon Basin, mainly grown by small-scale producers. Capsicum chinense plants in an experimental field in the northern Brazilian state of Amazonas were found exhibiting characteristic symptoms of viral infection. Leaf sap from symptomatic plants examined under a transmission electron microscope revealed the presence of elongated flexuous particles and isometric particles. Using molecular assays, the viruses were identified as pepper yellow mosaic virus (PepYMV) and cucumber mosaic virus (CMV). Aphids, identified as Aphis gossypii, were found colonizing the C. chinense plants in the field and may be the vector for both PepYMV and CMV. We report the first occurrence of these viruses infecting C. chinense in the state of Amazonas. (AU)
Subject(s)
Potyvirus , Cucumovirus , Microscopy, Electron, Transmission , VirusesABSTRACT
BACKGROUND The impact of arbovirus cocirculation in Brazil is unknown. Dengue virus (DENV) reinfection may result in more intense viraemia or immunopathology, leading to more severe disease. The Zika virus (ZIKV) epidemic in the Americas provided pathogenicity evidence that had not been previously observed in flavivirus infections. In contrast to other flaviviruses, electron microscopy studies have shown that ZIKV may replicate in viroplasm-like structures. Flaviviruses produce an ensemble of structurally different virions, collectively contributing to tissue tropism and virus dissemination. OBJECTIVES AND METHODS In this work, the Aedes albopictus mosquito cell lineage (C6/36 cells) and kidney epithelial cells from African green monkeys (Vero cells) were infected with samples of the main circulating arboviruses in Brazil [DENV-1, DENV-2, DENV-3, DENV-4, ZIKV, Yellow Fever virus (YFV) and Chikungunya virus (CHIKV)], and ultrastructural studies by transmission electron microscopy were performed. FINDINGS We observed that ZIKV, the DENV serotypes, YFV and CHIKV particles are spherical. ZIKV, DENV-1, -2, -3 and -4 presented diameters of 40-50 nm, and CHIKV presented approximate diameters of 50-60 nm. Viroplasm-like structures was observed in ZIKV replication cycle. MAIN CONCLUSIONS The morphogenesis of these arboviruses is similar to what has been presented in previous studies. However, we understand that further studies are needed to investigate the relationship between viroplasm-like structures and ZIKV replication dynamics.
Subject(s)
Animals , Arboviruses , Yellow Fever , Dengue/epidemiology , Epidemics , Chikungunya Fever/epidemiology , Zika Virus , Zika Virus Infection/epidemiology , Vero Cells , Brazil/epidemiology , Chlorocebus aethiopsABSTRACT
Abstract Introduction Riluzole (2-amino-6-trifluoromethoxy benzothiazole) is known as a neuroprotective, antioxidant, antiapoptotic agent. It may have beneficial effects on neuronal cell death due to cisplatin-induced ototoxicity. Objective To evaluate the effect of riluzole on cisplatin-induced ototoxicity in guinea pigs. Methods Twenty-four guinea pigs, studied in three groups, underwent auditory brainstem response evaluation using click and 8 kHz tone burst stimuli. Subsequently, 5 mg/kg of cisplatin were administered to all animals for 3 days intraperitoneally (i.p.) to induce ototoxicity. Half an hour prior to cisplatin, groups 1, 2 and 3 received 2 ml of saline i.p., 6 mg/kg of riluzole hydrochloride i.p., and 8 mg/kg of riluzole hydrochloride i.p., respectively, for 3 days. The auditory brainstem responses were repeated 24 hours after the last drug administration. The cochleae were analyzed by transmission electron microscopy (TEM). Results After drug administiration, for 8,000 Hz stimulus, group 1 had significantly higher threshold shifts when compared with groups 2 (p < 0.05) and 3 (p < 0.05), and there was no significant difference in threshold shifts between groups 2 and 3 (p > 0.05). Transmission electron microscopy findings demonstrated the protective effect of riluzole on the hair cells and the stria vascularis, especially in the group treated with 8 mg/kg of riluzole hydrochloride. Conclusion We can say that riluzolemay have a protective effect on cisplatin- induced ototoxicity. However, additional studies are needed to confirm these results and the mechanisms of action of riluzole.
Subject(s)
Animals , Male , Evoked Potentials, Auditory, Brain Stem/drug effects , Cisplatin/adverse effects , Riluzole/pharmacology , Hearing Loss, Sensorineural/chemically induced , Auditory Threshold/drug effects , Stria Vascularis/drug effects , Stria Vascularis/pathology , Cochlear Nerve/drug effects , Cochlear Nerve/pathology , Riluzole/therapeutic use , Models, Animal , Microscopy, Electron, Transmission , Guinea Pigs , Hair Cells, Auditory/drug effects , Hair Cells, Auditory/pathology , Nerve Degeneration/chemically inducedABSTRACT
Con la finalidad de evaluar la patogenia en cepas de Salmonella Typhimurium con mutaciones en los genes invG/invE de la Isla de Patogenicidad de Salmonella 1 (SPI-1) y de los genes ssaJ/ssaK en la SPI-2, se evaluaron los modelos asa intestinal ligada de ratón asociado a la observación de los tejidos por microscopía electrónica de transmisión (MET) y la producción de salmonelosis sistémica en ratón. Para ello, se utilizaron seis cepas de Salmonella: S. Typhimurium SL-1344 (cepa control) y sus derivadas mutantes: ∆invEG S. Typhimurium SL-1344 (mutante en SPI-1) y ∆ssaJK S. Typhimurium SL-1344 (mutante en SPI-2), S. Typhimurium (cepa clínica) y sus derivadas mutantes: ∆invEG S. Typhimurium y ∆ssaJK S. Typhimurium. Los resultados de MET permitieron verificar las alteraciones morfológicas del epitelio intestinal en el ratón infectado con cepas de Salmonella cuyos genes de patogenicidad estaban intactos. Fue comprobada la pérdida del poder invasivo solo en las cepas mutadas en la SPI-1. A través del modelo de salmonelosis sistémica en ratón se pudo comprobar la pérdida de la capacidad de diseminación en ambas mutantes. En conclusión los modelos permitieron verificar la importancia que tienen los genes invG/invE de la SPI-1 y ssaJ/ssaK de la SPI-2 en la patogenia de la salmonelosis, utilizando como modelo experimental de infección ratones BALB/c. Se sugieren estos modelos in vivo para evaluar mutantes de genes implicados en la patogenia de Salmonella, ya que representan una herramienta importante para la comprensión de la interacción Salmonella-hospedero(AU)
With the aim of evaluate the pathogenesis in Salmonella Typhimurium strains with mutations in genes invG/invE of Salmonella Pathogenicity Island 1 (SPI-1) and genes ssaJ/ssaK in the SPI-2 models were evaluated ligated intestinal loop associated mouse tissues by observation by transmission electron microscopy (TEM) and the production of mouse systemic salmonellosis. For this, we used six Salmonella strains: S. Typhimurium SL-1344 (control strain) and its derived mutants: ΔinvEG S. Typhimurium SL-1344 (mutant in SPI-1) and ΔssaJK S. Typhimurium SL-1344 (mutant in SPI-2), S. Typhimurium (clinical isolate) and its derived mutants: ΔinvEG S.Typhimurium and ΔssaJK S. Typhimurium. TEM results allowed us to verify the morphological alterations of the intestinal epithelium in mice infected with Salmonella strains whose pathogenicity genes were intact. It was proven invasive power loss only in strains mutated in the SPI-1. Through systemic salmonellosis model mouse we noted the loss of the ability to spread in both mutants. In conclusion, the models allowed us to verify the importance of the invG/invE genes of SPI-1 and ssaJ/ssaK of SPI-2 in the pathogenesis of salmonellosis, using BALB/c mice as an experimental model of infection. These in vivo models are suggested to evaluate mutants of genes involved in the pathogenesis of Salmonella, since they represent an important tool for the understanding of the Salmonella-host interaction(AU)
Subject(s)
Animals , Mice , Salmonella typhimurium/pathogenicity , Genomic Islands/genetics , Microscopy, Electron, Transmission/methods , Mutation/geneticsABSTRACT
This study aimed at assessing the cell cycle, and anatomical and biochemical changes that the embryonic axis of Araucaria angustifolia undergoes during development, focusing on the maturation stage. During all development, cells exhibited intense metabolic activity with an abundance of mitochondria, lipid bodies, and vacuolated cells. The continued accumulation of starch and protein was observed by LM and TEM and indicated by spectra of FTIR. Cell differentiation of the procambium was observed with a thickening of the cell wall and the formation of resiniferous ducts. At Stage III and IV, cells exhibited structural changes such as altered or elongated mitochondria and presence of plastoglobules. These results suggest that there is a gradual transition from developmental metabolism to germination metabolism. Such changes can contribute to the rapid germination of seeds right after their dispersion, making it an ecological strategy to reduce post-dispersal exposure to predators and to avoid damage from reduced moisture.
Subject(s)
Germination , Seeds/anatomy & histology , Seeds/growth & development , Seeds/chemistryABSTRACT
@#Introduction: Dengue virus (DENV), the causative agent of dengue disease exists in sylvatic and endemic ecotypes. The cell morphological changes and viral morphogenesis of two dengue ecotypes were examined at the ultrastructural level to identify potential similarities and differences in the surrogate model of enzootic host. Materials and Methods: Vero cells were inoculated with virus at a multiplicity of infection (MOI) of 0.1. Cell cultures were harvested over a time course and processed for transmission electron microscopic imaging. Results: The filopodia protrusions on cell periphery preceded virus entry. Additionally, sylvatic DENV infection was found spreading slower than the endemic DENV. Morphogenesis of both dengue ecotypes was alike but at different level of efficiency in the permissive cells. Conclusions: This is the first ultrastructural study on sylvatic DENV and this comparative study revealed the similarities and differences of cellular responses and morphogenesis of two dengue ecotypes in vitro. The study revealed the weaker infectivity of sylvatic DENV in the surrogate model of enzootic host, which supposed to support better replication of enzootic DENV than endemic DENV.
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Immunoglobulin G against myelin oligodendrocyte glycoprotein (MOG-IgG) is detectable in neuromyelitis optica spectrum disorder (NMOSD) without aquaporin-4 IgG (AQP4-IgG), but its pathogenicity remains unclear. In this study, we explored the pathogenic mechanisms of MOG-IgG in vitro and in vivo and compared them with those of AQP4-IgG. MOG-IgG-positive serum induced complement activation and cell death in human embryonic kidney (HEK)-293T cells transfected with human MOG. In C57BL/6 mice and Sprague-Dawley rats, MOG-IgG only caused lesions in the presence of complement. Interestingly, AQP4-IgG induced astroglial damage, while MOG-IgG mainly caused myelin loss. MOG-IgG also induced astrocyte damage in mouse brains in the presence of complement. Importantly, we also observed ultrastructural changes induced by MOG-IgG and AQP4-IgG. These findings suggest that MOG-IgG directly mediates cell death by activating complement in vitro and producing NMOSD-like lesions in vivo. AQP4-IgG directly targets astrocytes, while MOG-IgG mainly damages oligodendrocytes.
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OBJECTIVES: The emergence of resistant bacteria is being increasingly reported around the world, potentially threatening millions of lives. Amongst resistant bacteria, methicillin-resistant Staphylococcus aureus (MRSA) is the most challenging to treat. This is due to emergent MRSA strains and less effective traditional antibiotic therapies to Staphylococcal infections. The use of bacteriophages (phages) against MRSA is a new, potential alternate therapy. In this study, morphology, genetic and protein structure of lytic phages against MRSA have been analysed. METHODS: Isolation of livestock and sewage bacteriophages were performed using 0.4 μm membrane filters. Plaque assays were used to determine phage quantification by double layer agar method. Pure plaques were then amplified for further characterization. Sulfate-polyacrylamide gel electrophoresis and random amplification of polymorphic DNA were run for protein evaluation, and genotyping respectively. Transmission electron microscope was also used to detect the structure and taxonomic classification of phage visually. RESULTS: Head and tail morphology of bacteriophages against MRSA were identified by transmission electron microscopy and assigned to the Siphoviridae family and the Caudovirales order. CONCLUSION: Bacteriophages are the most abundant microorganism on Earth and coexist with the bacterial population. They can destroy bacterial cells successfully and effectively. They cannot enter mammalian cells which saves the eukaryotic cells from lytic phage activity. In conclusion, phage therapy may have many potential applications in microbiology and human medicine with no side effect on eukaryotic cells.