RESUMO
Euschistus heros (Fabricius, 1798) (Heteroptera: Pentatomidae) is a soybean pest in Brazil. It has a reproductive success that may be associated with the female receptaculum seminis or spermatheca, a reproductive organ for spermatozoa storage until the oocyte fertilization. This study describes the anatomy and histology of the female receptaculum seminis in E. heros. The female receptaculum seminis was dissected and analyzed with a stereomicroscope, following standard procedures for histological and histochemical analyses. The female receptaculum seminis of E. heros has a spherical caspula seminalis and a duct. The epithelial cells of the capsula seminalis have two cell layers with basal one presenting columnar cells with a collecting canaliculus opening in the lumen. The apical layer has cuboidal cells. The cytoplasm in both cell layers was rich in protein. These features suggest a secretory function of these cells. The duct has four regions characterized by muscular pars intermedialis with anterior and posterior cuticular flanges, an elongated and narrow distal ductus receptaculi, a well-developed enlarged vesicular area, and a proximal ductus receptaculi, which indicate several functions, such as control the release and transport of spermatozoa and secretory. These results contribute to the comprehension of the reproductive biology of this agricultural pest.
Assuntos
Genitália Feminina , Heterópteros , Animais , Feminino , Genitália Feminina/anatomia & histologia , Genitália Feminina/ultraestrutura , Heterópteros/anatomia & histologia , Masculino , Hemípteros/anatomia & histologia , Hemípteros/classificação , Hemípteros/fisiologia , Hemípteros/ultraestrutura , BrasilRESUMO
Schistosoma mansoni, an intravascular parasitic worm and the causative agent of schistosomiasis, relies on its tegument (outer layer) for survival and host interaction. This study explored the morphology and mechanical properties of S. mansoni tegument using Atomic Force Microscopy (AFM). Notably, we employed the PeakForce Quantitative Nanomechanical Mapping (PF-QNM) mode in air, enabling simultaneous acquisition of 3D topography and mechanical property contrasts (adhesion, elastic modulus). Additionally, nanoindentation (AFM contact mode) was performed on female worm tegument for elastic modulus measurement. Both techniques revealed an elastic modulus range of fractions or units of GPa for the tegument. Interestingly, mechanical property maps, particularly adhesion contrast, displayed a recurring pattern of light and dark bands. We also measured the depth of annular furrows on the female tegument, finding an average of 128 ± 10 nm. These findings establish AFM, particularly PF-QNM, as a valuable tool to characterize S. mansoni tegument properties, offering insights for future investigations into parasite biology and its response to immunological or pharmacological challenges.
Assuntos
Microscopia de Força Atômica , Schistosoma mansoni , Schistosoma mansoni/ultraestrutura , Schistosoma mansoni/fisiologia , Microscopia de Força Atômica/métodos , Animais , Feminino , Módulo de Elasticidade , Fenômenos BiomecânicosRESUMO
This essay discusses how the ultrastructural changes in chloroplasts, particularly the mechanisms of thylakoid membrane unstacking, help maintain the photosynthetic performance of photosystem II (PSII) under stress conditions. This phenomenon may facilitate the repair of damaged PSII by providing access to the repair machinery. It is argued that this PSII repair mechanism accelerates PSII recovery, optimizing photosynthetic processes in stressed plants. Although some studies demonstrate the relationship between thylakoid membrane unstacking in stress conditions, these studies were developed with model species under controlled conditions. Thus, this essay serves as a validation tool for these previous studies, because it demonstrates that the relationships between ultrastructural changes in chloroplasts and the functioning of PSII are essential acclimative strategies for nonmodel plants to survive the constant edaphoclimatic changes of natural environments. Understanding these subcellular dynamics can significantly inform biologists about the plastic potential of plants, especially in heterogeneous environments. An integrated approach in future studies is necessary, highlighting the importance of exploring plant functional traits at multiple scales, because subcellular characteristics have great potential to understand plant acclimatization.
Assuntos
Cloroplastos , Complexo de Proteína do Fotossistema II , Aclimatação , Cloroplastos/ultraestrutura , Cloroplastos/metabolismo , Cloroplastos/fisiologia , Fotossíntese , Complexo de Proteína do Fotossistema II/metabolismo , Tilacoides/ultraestrutura , Tilacoides/metabolismoRESUMO
Cryo-electron microscopy and tomography have allowed us to unveil the remarkable structure of icosahedral viruses. However, in the past few years, the idea that these viruses must have perfectly symmetric virions, but in some cases, it might not be true. This has opened the door to challenging paradigms in structural virology and raised new questions about the biological implications of "unusual" or "defective" symmetries and structures. Also, the continual improvement of these technologies, coupled with more rigorous sample purification protocols, improvements in data processing, and the use of artificial intelligence, has allowed solving the structure of sub-viral particles in highly heterogeneous samples and finding novel symmetries or structural defects. In this review, I initially analyzed the case of the symmetry and composition of hepatitis B virus-produced spherical sub-viral particles. Then, I focused on Alphaviruses as an example of "imperfect" icosahedrons and analyzed how structural biology has changed our understanding of the Alphavirus assembly and some biological implications arising from these discoveries.
Assuntos
Alphavirus , Microscopia Crioeletrônica , Vírus da Hepatite B , Vírion , Montagem de Vírus , Microscopia Crioeletrônica/métodos , Vírus da Hepatite B/ultraestrutura , Vírion/ultraestrutura , Alphavirus/ultraestrutura , Alphavirus/fisiologia , Capsídeo/ultraestrutura , Capsídeo/química , Vírus/ultraestrutura , Vírus/química , HumanosRESUMO
OBJECTIVE: This work aimed to evaluate the in vitro effect of zinc oxide-eugenol paste (ZOE) on planktonic aggregates (EfPA) and biofilm (EfBio) of Enterococcus faecalis, focusing on their morphological aspects observed and analyzed using atomic force microscopy (AFM). DESIGN: The eugenol and paste were characterized by Gas Chromatography coupled with Mass Spectrometry (GC-MS) and Fourier Transform Infrared Spectroscopy (FTIR), respectively. The effect of ZOE on EfPA and EfBio was evaluated by a direct-contact test through colony counting and crystal violet staining protocol. AFM images of untreated and treated EfPA and EfBio growth on bovine dentin were obtained to analyze the morphological damage caused by the treatments. RESULTS: The characterization showed high purity in the eugenol composition and chemical interaction between the components of the paste. A bactericidal effect on aggregates was observed after 6 h of exposure, and on biofilm after 24 h of treatment (p < 0.001). A disruptive effect on the biofilm was also evident. AFM images revealed the formation of EfPA, with a notable presence of an exopolysaccharide matrix. After 6 h of ZOE treatment, there was a significant increase in the size and surface roughness profile of treated cells (p < 0.05). Loss of typical cell morphology was observed after 24 h. The effect on the biofilm showed a tendency towards a less condensed biofilm pattern in the treated group, with no differences in surface roughness. CONCLUSION: ZOE presents bactericidal action on EfPA and EfBio, promoting significant morphological changes after treatment, especially in the aggregates.
Assuntos
Biofilmes , Enterococcus faecalis , Microscopia de Força Atômica , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Enterococcus faecalis/efeitos dos fármacos , Enterococcus faecalis/ultraestrutura , Animais , Bovinos , Espectroscopia de Infravermelho com Transformada de Fourier , Plâncton/efeitos dos fármacos , Antibacterianos/farmacologia , Cromatografia Gasosa-Espectrometria de Massas , Eugenol/farmacologia , Cimento de Óxido de Zinco e Eugenol/farmacologia , Dentina/efeitos dos fármacos , Dentina/microbiologia , Materiais Restauradores do Canal Radicular/farmacologiaRESUMO
Cerebrospinal fluid-contacting neurons (CSF-cNS) are considered mechanoreceptors and chemoreceptors involved in detecting changes in CSF circulation. However, considering that recent data suggest that this type of cell could exert an active response when an external stimulus is sensed, identification of CSF-cNS may be relevant. In this regard, some data suggest that a neuronal connection exists between the ventral region of the hypothalamic paraventricular nucleus (PVN) and rostral agranular insular cortex (RAIC); indeed, a potential CSF-cNS is hypothesized. However, a detailed analysis of this connection has not been conducted. Thus, using neuronal tracers (Fluoro-Gold® (FG) and cholera toxin (ChT)) coupled with transmission electron microscopy and immunofluorescence assays against Fluoro-Gold®, oxytocin (OXT), vasopressin (AVP) and oxytocin receptors (OTR), we describe an oxytocinergic or vasopressinergic CSF-cNS between the PVN and RAIC. Our results showed that CSF-cNS along the PVN labelled with oxytocin and/or AVP were present in dendritic projections near the third ventricle. This CSF-cNS in the PVN seems to project to the RAIC. Inside the RAIC, ultrastructural analysis showed that axons immunopositive for oxytocin from the PVN sustained synaptic connections with neurons that expressed OTR. These findings show that the CSF-cNS from the PVN sends projections to the RAIC. To the best of our knowledge, the relevance of CSF-cNS has not been elucidated; however, we hypothesized that the activation of cells could concomitantly release neuropeptides (i.e., oxytocin and AVP) in the CSF and RAIC. Thus, further analysis of the impact of neuropeptides released into the third ventricle and RAIC is warranted.
Assuntos
Córtex Cerebral , Neurônios , Ocitocina , Núcleo Hipotalâmico Paraventricular , Animais , Neurônios/ultraestrutura , Neurônios/metabolismo , Ocitocina/líquido cefalorraquidiano , Ocitocina/metabolismo , Ratos , Masculino , Córtex Cerebral/ultraestrutura , Córtex Cerebral/metabolismo , Córtex Cerebral/citologia , Núcleo Hipotalâmico Paraventricular/metabolismo , Núcleo Hipotalâmico Paraventricular/citologia , Núcleo Hipotalâmico Paraventricular/ultraestrutura , Ratos Wistar , Receptores de Ocitocina/metabolismo , Líquido Cefalorraquidiano/metabolismo , Imunofluorescência/métodos , Vasopressinas/metabolismo , Vasopressinas/líquido cefalorraquidiano , Vias Neurais/ultraestrutura , Vias Neurais/metabolismo , Microscopia Eletrônica de TransmissãoRESUMO
Molar incisor hypomineralisation (MIH) is a qualitative type of enamel defect, which occurs due to a failure in the biomineralisation process of the enamel organic matrix during amelogenesis. The tooth enamel affected by MIH shows changes in its chemical, structural, and mechanical properties, leading to different clinical repercussions. The color of MIH opacities varies from opaque white to yellow/brown, and elemental analyses of these lesions show a lower calcium and phosphate content, minerals that are more abundant in sound enamel. Furthermore, the incorporation of other molecules occurs, such as carbonate, a component that provides a greater degree of solubility, thus making hypomineralised enamel more susceptible to posteruptive fractures. At a structural level, the layer of hydroxyapatite crystals appears to be disorganized, with morphological changes, implying a greater degree of porosity in the structure. The increase in porosity of the structure may be associated with dental hypersensitivity, a common clinical repercussion among patients with MIH. Among the mechanical properties, a decrease in hardness and modulus of elasticity occurs, and this also makes the enamel more fragile. Deficiency in biomineralisation can be caused by changes in the function of ameloblasts or by failures at the intercellular junction that result in lower activity of proteases such as MMP-20 and KLK4. The increase in proteins in the organic matrix of enamel impairs the growth and incorporation of minerals into the hydroxyapatite crystals, so that the enamel becomes hypomineralised and has larger organic content, thus having an impact on its properties. These changes present in the enamel with MIH help to explain the clinical repercussions caused by this condition.
Assuntos
Hipoplasia do Esmalte Dentário , Esmalte Dentário , Humanos , Esmalte Dentário/patologia , Esmalte Dentário/ultraestrutura , Hipoplasia do Esmalte Dentário/patologia , Durapatita , Desmineralização do Dente/patologia , DurezaRESUMO
Sperm morphology is considered the best indicator of male fertility. In Neotropical bats, important aspects of sperm morphology have been scantly studied. The aim of the present study was to characterize and compare the sperm morphology and morphometry of Artibeus planirostris and Sturnira erythromos. A total of 11 specimens were analyzed from the Colección de Mamíferos Lillo: five A. planirostris and six S. erythromos. The fixed epididymis were extracted and macerated in Farmer's solution, followed by the routine cytological procedure with different stains. To carry out the description and morphometric analysis, microphotographs were taken under an optical, epifluorescence and scanning electron microscope. A total of 50 sperm from each individual were measured for morphometric analysis. The percentage of normal/abnormal spermatozoa was estimated and the sperm abnormalities were classified. Both species showed morphologically simple spermatozoa with a spatulate head, a short neck, a helical midpiece and a tail that tapers at the final end, similar to other species of Phyllostomidae. The differences observed were: apex of the head was conical in A. planirostris and was oval in S. erythromos; longer head and midpiece in S. erythomos and longer sperm in A. planirostris. Both species showed a high percentage of sperm with normal appearance: 65% for A. planirostris and 72% for S. erythromos. The main sperm abnormalities were: scattered tails and heads, coiled tails, folded midpieces and presence of cytoplasmic droplets. The present work will improve the understanding of their reproductive biology. RESEARCH HIGHLIGHTS: Morphological descriptions and morphometric analyses of the sperm of Artibeus planirostris and Sturnira erythromos were carried out with optical, epifluorescence and scanning electron microscopy.
Assuntos
Quirópteros , Microscopia Eletrônica de Varredura , Espermatozoides , Animais , Masculino , Quirópteros/anatomia & histologia , Espermatozoides/ultraestrutura , Espermatozoides/citologia , Epididimo/ultraestrutura , Epididimo/citologia , Epididimo/anatomia & histologiaRESUMO
This study investigated whether chronic undernutrition alters the mitochondrial structure and function in renal proximal tubule cells, thus impairing fluid transport and homeostasis. We previously showed that chronic undernutrition downregulates the renal proximal tubules (Na++K+)ATPase, the main molecular machine responsible for fluid transport and ATP consumption. Male rats received a multifactorial deficient diet, the so-called Regional Basic Diet (RBD), mimicking those used in impoverished regions worldwide, from weaning to a juvenile age (3 months). The diet has a low content (8 %) of poor-quality proteins, low lipids, and no vitamins compared to control (CTR). We investigated citrate synthase activity, mitochondrial respiration (oxygraphy) in phosphorylating and non-phosphorylating conditions with different substrates/inhibitors, potential across the internal membrane (Δψ), and anion superoxide/H2O2 formation. The data were correlated with ultrastructural alterations evaluated using transmission electron microscopy (TEM) and focused ion beam scanning electron microscopy (FIB-SEM). Citrate synthase activity decreased (â¼50 %) in RBD rats, accompanied by a similar reduction in respiration in non-phosphorylating conditions, maximum respiratory capacity, and ATP synthesis. The Δψ generation and its dissipation after carbonyl cyanide-4-(trifluoromethoxy) phenylhydrazone remained unmodified in the survival mitochondria. H2O2 production increased (â¼100 %) after Complex II energization. TEM demonstrated intense matrix vacuolization and disruption of cristae junctions in a subpopulation of RBD mitochondria, which was also demonstrated in the 3D analysis of FIB-SEM tomography. In conclusion, chronic undernutrition impairs mitochondrial functions in renal proximal tubules, with profound alterations in the matrix and internal membrane ultrastructure that culminate with the compromise of ATP supply for transport processes.
Assuntos
Desnutrição , Mitocôndrias , Ratos Wistar , Animais , Masculino , Mitocôndrias/metabolismo , Mitocôndrias/ultraestrutura , Mitocôndrias/patologia , Desnutrição/metabolismo , Desnutrição/patologia , Desnutrição/complicações , Ratos , Túbulos Renais Proximais/metabolismo , Túbulos Renais Proximais/patologia , Túbulos Renais Proximais/ultraestrutura , Citrato (si)-Sintase/metabolismo , Respiração Celular , Rim/metabolismo , Rim/patologia , Rim/ultraestruturaRESUMO
The horned octopod Eledone cirrhosa, a medium-sized species found in Arabian Gulf off Saudi Arabia, was collected monthly from the Arabian Gulf off Dammam city during January to December 2022. Samples were dissected and prepared for examination using transmission electron microscopy. During genital maturation, seminiferous tubules are established in the testis, with active spermatogonia dividing. Spermatocytes 1 are observed in the tubule, followed by an increase in spermatogonia and spermatocytes in August. Spermiogenesis begins, with spherical spermatids evolving into elongated spermatids. In September, active spermatogonia, meiotic divisions, and increased spermiogenesis continue. Spermatozoa appear in Needham's pouch, indicating sexual maturity. The ovary undergoes various stages of development, with oocytes at stage I in June and July, followed by stage II in October and November. In stage III, follicular cords invade the oocyte's cytoplasm, forming numerous lipid inclusions and protein granules. The cytoplasm contains cisternae of endoplasmic reticulum and a poorly developed Golgi apparatus. Stage IV occurs in November, characterized by the maximum development of follicular cords and the beginning of vitellogenesis. The ooplasm contains numerous lipid inclusions, a syncytium, and secretory cells. From December, stage V oocytes are mainly present, indicating the activity phase of maximum secretion. Yolk platelets accumulate in the oocyte ooplasm, and chorion forms at the zona pellucida. In January, the first smooth eggs are found in some octopuses' ovary, with their proportion increasing steadily. This study aimed to investigate the mitogenic action of gonadotropin and identify the periods of intense cell multiplication during the sexual cycle using cytological methods.
Assuntos
Microscopia Eletrônica de Transmissão , Octopodiformes , Ovário , Maturidade Sexual , Animais , Feminino , Masculino , Maturidade Sexual/fisiologia , Ovário/ultraestrutura , Ovário/anatomia & histologia , Ovário/citologia , Octopodiformes/anatomia & histologia , Estações do Ano , Testículo/ultraestrutura , Testículo/citologia , Espermatogênese/fisiologia , Oócitos/ultraestruturaRESUMO
PURPOSE: In this study, 143 lutjanid fishes representing four different species from the Northeast coast off Brazil were analyzed for parasites. The aim of the present study is to provide a detailed redescription of R. (I.) vicentei, collected from lutjanid fishes in Brazil, including the first observation of the species using scanning electron microscopy (SEM). METHODS: Nematodes found clarified in a crescent glycerin series, were photographed and measured (in mm), and some specimens destined for SEM. The Illustrations were made using an optical microscope with a drawing tube. RESULTS: Nematodes found were identified as Raphidascaris (Ichthyascaris) vicentei, infecting 6.29% of the examined fish. Detailed morphological analysis revealed the following characteristics observed for the first time in this species: labial papillae, narrow lateral alae and the detailed structure of male spicules. These contributions help filling the gaps in the literature and expand the knowledge of this parasite morphology. CONCLUSIONS: The presence of R. (I.) vicentei in four lutjanid species may indicates low host specificity, highlighting its adaptability to different hosts. Furthermore, new host records are given. This research provides the most comprehensive morphological description of R. (I.) vicentei to date, generating crucial insights for a better understanding of the parasitic biodiversity off the Brazilian Northeastern coast of Brazil, as well as establishing foundation for future investigations on the ecology and impacts of these parasites in fish populations from this region.
Assuntos
Doenças dos Peixes , Microscopia Eletrônica de Varredura , Animais , Brasil , Doenças dos Peixes/parasitologia , Microscopia Eletrônica de Varredura/veterinária , Masculino , Feminino , Peixes/parasitologia , Infecções por Ascaridida/veterinária , Infecções por Ascaridida/parasitologia , Infecções por Ascaridida/epidemiologia , Ascaridoidea/isolamento & purificação , Ascaridoidea/classificação , Ascaridoidea/anatomia & histologia , Ascaridoidea/ultraestruturaRESUMO
OBJECTIVES: An integrative taxonomic description of Aponurus laguncula (Lecithasteridae), a digenean parasitic species of Chaetodipterus faber (Acanthuriformes) from Brazilian Southeast, is provided. Morphological techniques, as whole mounted slides, histology and scanning electron microscopy, and molecular analyses supported that integrative description. METHODS: Fifteen digenean specimens were stained in hydrochloric carmine and mounted on permanent slides. Two specimens were stained in hematoxylin and eosin following histological routine processing. Four parasites were dehydrated through a graded ethanol series, critical point dried with carbon dioxide and coated with gold to scanning electron microscopy analysis. Sequence of the large ribosomal subunit (28S rDNA) gene was generated and used to construct a phylogeny based on maximum likelihood and Bayesian inference analyses. RESULTS: Morphological description and morphometric data obtained in present study were in accordance with previous studies of the species. Use of another morphological techniques, as scanning electron microscopy and histology, corroborated the observed features of whole mounted slides. Also, they provided a better observation of previous reported characteristics and new features reporting, such as an elongated hermaphroditic duct, a smooth tegument and cells that compose the prostatic gland. The molecular sequence obtained in the present study formed a robust clade with available sequences of species of Aponurus. CONCLUSIONS: The integrative taxonomic approach successfully combined morphological observations, including both previously reported features and new descriptions from histological and electron microscopy analyses, with molecular data to identify these specimens as A. laguncula. Moreover, the detailed characterization of structures, such as the gonads in A. laguncula, that would be challenging to analyze using a single technique, was possible. Further molecular studies with less conserved genetic markers should be conducted to understand phylogenetic relationships between Aponurus species.
Assuntos
Doenças dos Peixes , Microscopia Eletrônica de Varredura , Filogenia , Trematódeos , Infecções por Trematódeos , Animais , Brasil , Doenças dos Peixes/parasitologia , Trematódeos/genética , Trematódeos/classificação , Trematódeos/isolamento & purificação , Trematódeos/ultraestrutura , Trematódeos/anatomia & histologia , Microscopia Eletrônica de Varredura/veterinária , Infecções por Trematódeos/veterinária , Infecções por Trematódeos/parasitologia , RNA Ribossômico 28S/genética , Peixes/parasitologia , DNA Ribossômico/genética , DNA de Helmintos/genéticaRESUMO
AIM: The present study aimed to investigate the effects of a single bout of resistance exercise on mitophagy in human skeletal muscle (SkM). METHODS: Eight healthy men were recruited to complete an acute bout of one-leg resistance exercise. SkM biopsies were obtained one hour after exercise in the resting leg (Rest-leg) and the contracting leg (Ex-leg). Mitophagy was assessed using protein-related abundance, transmission electron microscopy (TEM), and fluorescence microscopy. RESULTS: Our results show that acute resistance exercise increased pro-fission protein phosphorylation (DRP1Ser616) and decreased mitophagy markers such as PARKIN and BNIP3L/NIX protein abundance in the Ex-leg. Additionally, mitochondrial complex IV decreased in the Ex-leg when compared to the Rest-leg. In the Ex-leg, TEM and immunofluorescence images showed mitochondrial cristae abnormalities, a mitochondrial fission phenotype, and increased mitophagosome-like structures in both subsarcolemmal and intermyofibrillar mitochondria. We also observed increased mitophagosome-like structures on the subsarcolemmal cleft and mitochondria in the extracellular space of SkM in the Ex-leg. We stimulated human primary myotubes with CCCP, which mimics mitophagy induction in the Ex-leg, and found that BNIP3L/NIX protein abundance decreased independently of lysosomal degradation. Finally, in another human cohort, we found a negative association between BNIP3L/NIX protein abundance with both mitophagosome-like structures and mitochondrial cristae density in the SkM. CONCLUSION: The findings suggest that a single bout of resistance exercise can initiate mitophagy, potentially involving mitochondrial ejection, in human skeletal muscle. BNIP3L/NIX is proposed as a sensitive marker for assessing mitophagy flux in SkM.
Assuntos
Mitofagia , Músculo Esquelético , Humanos , Mitofagia/fisiologia , Masculino , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiologia , Adulto , Mitocôndrias Musculares/metabolismo , Mitocôndrias Musculares/ultraestrutura , Treinamento Resistido , Adulto Jovem , Proteínas de Membrana/metabolismoRESUMO
Seed water imbibition is critical to seedling establishment in tropical forests. The seeds of the neotropical tree Hymenaea courbaril have no oil reserves and have been used as a model to study storage cell wall polysaccharide (xyloglucan - XyG) mobilization. We studied pathways of water imbibition in Hymenaea seeds. To understand seed features, we performed carbohydrate analysis and scanning electron microscopy. We found that the seed coat comprises a palisade of lignified cells, below which are several cell layers with cell walls rich in pectin. The cotyledons are composed mainly of storage XyG. From a single point of scarification on the seed surface, we followed water imbibition pathways in the entire seed using fluorescent dye and NMRi spectroscopy. We constructed composites of cellulose with Hymenaea pectin or XyG. In vitro experiments demonstrated cell wall polymer capacity to imbibe water, with XyG imbibition much slower than the pectin-rich layer of the seed coat. We found that water rapidly crosses the lignified layer and reaches the pectin-rich palisade layer so that water rapidly surrounds the whole seed. Water travels very slowly in cotyledons (most of the seed mass) because it is imbibed in the XyG-rich storage walls. However, there are channels among the cotyledon cells through which water travels rapidly, so the primary cell walls containing pectins will retain water around each storage cell. The different seed tissue dynamic interactions between water and wall polysaccharides (pectins and XyG) are essential to determining water distribution and preparing the seed for germination.
Assuntos
Parede Celular , Cotilédone , Hymenaea , Pectinas , Polissacarídeos , Sementes , Água , Hymenaea/metabolismo , Parede Celular/metabolismo , Parede Celular/ultraestrutura , Parede Celular/química , Sementes/ultraestrutura , Sementes/metabolismo , Polissacarídeos/metabolismo , Água/metabolismo , Cotilédone/metabolismo , Pectinas/metabolismo , Glucanos/metabolismo , Xilanos/metabolismo , Celulose/metabolismo , Microscopia Eletrônica de VarreduraRESUMO
The discovery of mimivirus in 2003 prompted the search for novel giant viruses worldwide. Despite increasing interest, the diversity and distribution of giant viruses is barely known. Here, we present data from a 2012-2022 study aimed at prospecting for amoebal viruses in water, soil, mud, and sewage samples across Brazilian biomes, using Acanthamoeba castellanii for isolation. A total of 881 aliquots from 187 samples covering terrestrial and marine Brazilian biomes were processed. Electron microscopy and PCR were used to identify the obtained isolates. Sixty-seven amoebal viruses were isolated, including mimiviruses, marseilleviruses, pandoraviruses, cedratviruses, and yaraviruses. Viruses were isolated from all tested sample types and almost all biomes. In comparison to other similar studies, our work isolated a substantial number of Marseillevirus and cedratvirus representatives. Taken together, our results used a combination of isolation techniques with microscopy, PCR, and sequencing and put highlight on richness of giant virus present in different terrestrial and marine Brazilian biomes.
Assuntos
Vírus Gigantes , Brasil , Vírus Gigantes/isolamento & purificação , Vírus Gigantes/genética , Vírus Gigantes/classificação , Vírus Gigantes/ultraestrutura , Filogenia , Reação em Cadeia da Polimerase , Acanthamoeba castellanii/virologia , Acanthamoeba castellanii/isolamento & purificação , Microbiologia do Solo , Esgotos/virologia , Análise de Sequência de DNA , Água do Mar/virologia , Microbiologia da ÁguaRESUMO
Cucullanus lithodorasi n. sp. (Nematoda: Cucullanidae), collected from the intestine of Lithodoras dorsalis (Siluriformes) and waters of the north coast of Brazil is described based on light and scanning electron microscopic observations. The new species differs from its congeners in the number and arrangement of cloacal papillae: five precloacal pairs and five postcloacal pairs and presence of unpaired ventral papillae located slightly anterior to the cloaca. This is the third nominal species of the genus infecting fishes from brackish water from Brazil.
Assuntos
Peixes-Gato , Doenças dos Peixes , Microscopia Eletrônica de Varredura , Animais , Brasil , Peixes-Gato/parasitologia , Doenças dos Peixes/parasitologia , Masculino , Feminino , Nematoides/classificação , Nematoides/anatomia & histologia , Nematoides/ultraestrutura , Nematoides/isolamento & purificaçãoRESUMO
Microtubules are components of the cytoskeleton that perform essential functions in eukaryotes, such as those related to shape change, motility and cell division. In this context some characteristics of these filaments are essential, such as polarity and dynamic instability. In trypanosomatids, microtubules are integral to ultrastructure organization, intracellular transport and mitotic processes. Some species of trypanosomatids co-evolve with a symbiotic bacterium in a mutualistic association that is marked by extensive metabolic exchanges and a coordinated division of the symbiont with other cellular structures, such as the nucleus and the kinetoplast. It is already established that the bacterium division is microtubule-dependent, so in this work, it was investigated whether the dynamism and remodeling of these filaments is capable of affecting the prokaryote division. To this purpose, Angomonas deanei was treated with Trichostatin A (TSA), a deacetylase inhibitor, and mutant cells for histone deacetylase 6 (HDAC6) were obtained by CRISPR-Cas9. A decrease in proliferation, an enhancement in tubulin acetylation, as well as morphological and ultrastructural changes, were observed in TSA-treated protozoa and mutant cells. In both cases, symbiont filamentation occurred, indicating that prokaryote cell division is dependent on microtubule dynamism.
Assuntos
Divisão Celular , Microtúbulos , Simbiose , Microtúbulos/metabolismo , Microtúbulos/ultraestrutura , Microtúbulos/efeitos dos fármacos , Trypanosomatina/genética , Trypanosomatina/metabolismo , Trypanosomatina/ultraestrutura , Trypanosomatina/fisiologia , Ácidos Hidroxâmicos/farmacologia , Tubulina (Proteína)/metabolismo , Tubulina (Proteína)/genética , Bactérias/metabolismo , Bactérias/genética , Acetilação , Inibidores de Histona Desacetilases/farmacologia , Desacetilase 6 de Histona/metabolismo , Desacetilase 6 de Histona/genética , Citoesqueleto/metabolismo , Citoesqueleto/ultraestruturaRESUMO
The differential effects of cellular and ultrastructural characteristics on the optical properties of adaxial and abaxial leaf surfaces in the genus Tradescantia highlight the intricate relationships between cellular arrangement and pigment distribution in the plant cells. We examined hyperspectral and chlorophyll a fluorescence (ChlF) kinetics using spectroradiometers and optical and electron microscopy techniques. The leaves were analysed for their spectral properties and cellular makeup. The biochemical compounds were measured and correlated with the biophysical and ultrastructural features. The main findings showed that the top and bottom leaf surfaces had different amounts and patterns of pigments, especially anthocyanins, flavonoids, total phenolics, chlorophyll-carotenoids, and cell and organelle structures, as revealed by the hyperspectral vegetation index (HVI). These differences were further elucidated by the correlation coefficients, which influence the optical signatures of the leaves. Additionally, ChlF kinetics varied between leaf surfaces, correlating with VIS-NIR-SWIR bands through distinct cellular structures and pigment concentrations in the hypodermis cells. We confirmed that the unique optical properties of each leaf surface arise not only from pigmentation but also from complex cellular arrangements and structural adaptations. Some of the factors that affect how leaves reflect light are the arrangement of chloroplasts, thylakoid membranes, vacuoles, and the relative size of the cells themselves. These findings improve our knowledge of the biophysical and biochemical reasons for leaf optical diversity, and indicate possible implications for photosynthetic efficiency and stress adaptation under different environmental conditions in the mesophyll cells of Tradescantia plants.
Assuntos
Folhas de Planta , Tradescantia , Tradescantia/metabolismo , Folhas de Planta/metabolismo , Folhas de Planta/ultraestrutura , Fluorescência , Clorofila/metabolismo , Clorofila A/metabolismoRESUMO
Obesity is a complex chronic disease characterized by excess body fat (adipose) that is harmful to health and has been a major global health problem. It may be associated with several diseases, such as nonalcoholic fatty liver disease (NAFLD). Polyunsaturated fatty acids (PUFA) are lipid mediators that have anti-inflammatory characteristics and can be found in animals and plants, with capybara oil (CO) being a promising source. So, we intend to evaluate the hepatic pathophysiological alterations in C57Bl/6 mice with NAFLD, caused by obesity, and the possible beneficial effects of OC in the treatment of this disease. Eighteen 3-month-old male C57Bl/6 mice received a control or high-fat diet for 18 weeks. From the 15th to the 18th week, the animals received treatment-through orogastric gavage-with placebo or free capybara oil (5 g/kg). Parameters inherent to body mass, glucose tolerance, evaluation of liver enzymes, percentage of hepatic steatosis, oxidative stress, the process of cell death with the apoptotic biomarkers (Bax, Bcl2, and Cytochrome C), and the ultrastructure of hepatocytes were analyzed. Even though the treatment with CO was not able to disassemble the effects on the physiological parameters, it proved to be beneficial in reversing the morphological and ultrastructural damage present in the hepatocytes. Thus, demonstrating that CO has beneficial effects in reducing steatosis and the apoptotic pathway, it is a promising treatment for NAFLD.
Assuntos
Apoptose , Fígado , Hepatopatia Gordurosa não Alcoólica , Óleos , Roedores , Camundongos Endogâmicos C57BL , Hepatopatia Gordurosa não Alcoólica/etiologia , Hepatopatia Gordurosa não Alcoólica/terapia , Masculino , Animais , Camundongos , Hepatócitos/efeitos dos fármacos , Hepatócitos/patologia , Hepatócitos/ultraestrutura , Óleos/farmacologia , Óleos/uso terapêutico , Obesidade/complicações , Apoptose/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/patologia , Fígado/ultraestrutura , Oxirredutases/metabolismo , Ativação Enzimática/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacosRESUMO
Lacrymaria olor cytoskeleton and membrane "origami" enables rapid cell hyperextension.