Light Microscopic Methods Research Articles

Physicochemical Characterization of Cassava (Manihot esculenta) and Potato (Ipomea batatas) Varieties from Southeast of Nigeria in Comparison with Agarose for use in the Separation of Deoxyribonucleic Acid

Starch is an essential biomaterial and food product globally used for different purposes. This study determined the physicochemical composition of starch extracted from selected cassava (M.ExOboma I and M.ExOboma II) and sweet potato (I.ExOboma I and I.ExOboma II) varieties in comparison with agarose for use in the separation of deoxyribonucleic acid. Starch extraction was carried out using standard procedure. Granule morphology and amylose-amylopectin contents were determined using Polarized Light Microscopy and Dual Wavelength Iodine-Binding methods respectively. Relationships between starch properties were determined using correlation analysis. The result of the starch granule morphology revealed that there was no significant difference (p > 0.05) in the pore sizes of M.ExOboma I (5.527 ± 1.9346 µm) and M.ExOboma II (5.650 ± 1.0472 µm). Similarly, I.ExOboma I (8.275 ± 1.5064 µm) and I.ExOboma II (6.075 ± 2.3838 µm) showed no significant difference (p > 0.05) in their pore sizes. Meanwhile, the pore size of agarose was reported to be within the range of 6 to 35μm. No significant difference (p > 0.05) was also observed in the ratios of amylose and amylopectin (Am:Ap) contents between the varieties of cassava (M.ExOboma I 25:75 and M.ExOboma II 24:77) and sweet potato (I.ExOboma I 26:72 and I.ExOboma II 27:75). No significant difference (P > 0.05) between the pH range values (7.7 to 7.8) of cassava and sweet potato with that of agarose (7.5). The study also revealed that there were significant differences (p ≤ 0.05) in the clarity as well as the purity level of the starch samples compared to agarose. The results of this study are of great significance in predicting starch functionality and will form a basis for the improvement of the physicochemical attributes of starch for use in gel electrophoresis for the separation of biomolecules.

Embryonic development of the moon jellyfish Aurelia aurita (Cnidaria, Scyphozoa): another variant on the theme of invagination.

BackgroundAurelia aurita (Scyphozoa, Cnidaria) is an emblematic species of the jellyfish. Currently, it is an emerging model of Evo-Devo for studying evolution and molecular regulation of metazoans’ complex life cycle, early development, and cell differentiation. For Aurelia, the genome was sequenced, the molecular cascades involved in the life cycle transitions were characterized, and embryogenesis was studied on the level of gross morphology. As a reliable representative of the class Scyphozoa, Aurelia can be used for comparative analysis of embryonic development within Cnidaria and between Cnidaria and Bilateria. One of the intriguing questions that can be posed is whether the invagination occurring during gastrulation of different cnidarians relies on the same cellular mechanisms. To answer this question, a detailed study of the cellular mechanisms underlying the early development of Aurelia is required.MethodsWe studied the embryogenesis of A. aurita using the modern methods of light microscopy, immunocytochemistry, confocal laser microscopy, scanning and transmission electron microscopy.ResultsIn this article, we report a comprehensive study of the early development of A. aurita from the White Sea population. We described in detail the embryonic development of A. aurita from early cleavage up to the planula larva. We focused mainly on the cell morphogenetic movements underlying gastrulation. The dynamics of cell shape changes and cell behavior during invagination of the archenteron (future endoderm) were characterized. That allowed comparing the gastrulation by invagination in two cnidarian species—scyphozoan A. aurita and anthozoan Nematostella vectensis. We described the successive stages of blastopore closure and found that segregation of the germ layers in A. aurita is linked to the ’healing’ of the blastopore lip. We followed the developmental origin of the planula body parts and characterized the planula cells’ ultrastructure. We also found that the planula endoderm consists of three morphologically distinct compartments along the oral-aboral axis.ConclusionsEpithelial invagination is a fundamental morphogenetic movement that is believed as highly conserved across metazoans. Our data on the cell shaping and behaviours driving invagination in A. aurita contribute to understanding of morphologically similar morphogenesis in different animals. By comparative analysis, we clearly show that invagination may differ at the cellular level between cnidarian species belonging to different classes (Anthozoa and Scyphozoa). The number of cells involved in invagination, the dynamics of the shape of the archenteron cells, the stage of epithelial-mesenchymal transition that these cells can reach, and the fate of blastopore lip cells may vary greatly between species. These results help to gain insight into the evolution of morphogenesis within the Cnidaria and within Metazoa in general.

Extranuptial nectaries in bromeliads: a new record for Pitcairnia burchellii and perspectives for Bromeliaceae.

Nectar plays important roles in the relationship between plants and other organisms, both within pollination systems and as a defense mechanism. In the latter case, extranuptial nectaries (ENNs) usually attract patrolling arthropods that reduce herbivory. ENNs have been frequently reported within the "xeric clade" of Bromeliaceae, but their occurrence in other groups of bromeliads is largely unexplored, especially considering their position, secretory activity and structure. After observing the presence of ants constantly patrolling the inflorescences of Pitcairnia burchellii Mez, we searched for the presence, secretory activity, and structure of ENNs in this species. We also provide a brief review of the occurrence ENNs in Bromeliaceae. The distribution of nectaries was assessed using ant-exclusion experiments, while structural analysis was performed using standard methods for light and scanning electron microscopy. The presence of sugars in the secretion was assessed by thin-layer chromatography and glucose strip tests. Nectaries in P. burchelli are non-structured glands on the adaxial surface of floral bracts and sepals. Bracts and sepals are distinct spatial units that act over time in the same strategy of floral bud protection. Literature data reveals that ENNs might be more common within Bromeliaceae than previously considered, comprising a homoplastic feature in the family. Future perspectives and evolutionary and taxonomic implications are discussed.

PD21-01 PATHOLOGICAL CHANGES IN THE KIDNEYS IN PATIENTS WITH ACUTE RENAL INJURY DUE TO CORONAVIRUS INFECTION

You have accessJournal of UrologyCME1 May 2022PD21-01 PATHOLOGICAL CHANGES IN THE KIDNEYS IN PATIENTS WITH ACUTE RENAL INJURY DUE TO CORONAVIRUS INFECTION Valentin Pavlov, Dmitry Vishnyakov, Anushavan Papoyan, Aleksandr Alekseev, and Ildar Kabirov Valentin PavlovValentin Pavlov More articles by this author , Dmitry VishnyakovDmitry Vishnyakov More articles by this author , Anushavan PapoyanAnushavan Papoyan More articles by this author , Aleksandr AlekseevAleksandr Alekseev More articles by this author , and Ildar KabirovIldar Kabirov More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002559.01AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Acute kidney injury (AKI) in coronavirus infection (COVID-19) caused by the SARS-CoV-2 virus is much more common than previously thought and is associated with severe disease and high mortality. Despite the fact that the respiratory and immune systems are the main targets of the COVID-19 virus, AKI is also observed, identified by the occurrence of proteinuria or hematuria, an increase in serum urea and creatinine levels. The aim of the study is to assess the pathomorphological changes in the kidneys in 100 cases of autopsy of patients with COVID-19 using light microscopy and immunohistochemical diagnostic methods in order to clarify the possible mechanism of AKI. METHODS: The study was carried out using samples obtained from 100 patients, the time interval of the onset of the disease corresponded to the 4th wave of the peak of the incidence in Russia (from June 2021). The age of patients varied from 37 to 94 years 72 (σ=12.5), men - 34, women - 66. Patients with chronic kidney disease, diabetes mellitus and cancer were not included in the analysis. The cause of death in all cases was acute respiratory failure, histologically defined as diffuse alveolar injury. AKI in accordance with the KDIGO criteria was detected in 34 patients. RESULTS: On light microscopy, diffuse massive damage to the proximal tubules with loss of the brush border, degeneration of vacuoles was detected in 46 patients, massive necrosis of the tubules in 11 patients. In 65 patients, an extremely pronounced congestion of paretic dilated vessels with widespread paravasal hemorrhages was revealed. Paravasal lymphoid infiltration of the vascular endothelium was detected in 27 patients. Severe sludge syndrome in small and medium-sized vessels in 46 patients. In almost all cases, hemosiderin granules and hyaline casts were found. The quantitative and qualitative composition of tissue macrophages corresponded to the population data, without visible correlations with the disease. CONCLUSIONS: According to the study, the factors contributing to AKI include systemic hypoxia, abnormal coagulation, increased catabolism due to fever, drug-related rhabdomyolysis or hyperventilation with increased serum degradation products. Thus, our research provides evidence for AKI during the progression of COVID-10. These results contribute to a better understanding of the course and progression of SARS-CoV-2 virus infection. Source of Funding: Federal State Budgetary Educational Institution of Higher Education Bashkir State Medical University © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e361 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Valentin Pavlov More articles by this author Dmitry Vishnyakov More articles by this author Anushavan Papoyan More articles by this author Aleksandr Alekseev More articles by this author Ildar Kabirov More articles by this author Expand All Advertisement PDF DownloadLoading ...

Morphological and Structural Details of Tomato Seed Coat Formation: A Different Functional Role of the Inner and Outer Epidermises in Unitegmic Ovule

In order to understand how and what structures of the tomato ovule with a single integument form the seed coat of a mature seed, a detailed study of the main development stages of the tomato ovule integument was carried out using the methods of light and electron microscopy. The integument itself it was shown to transform in the course of development into the coat (skin) of a mature seed, but the outer and inner epidermises of the integument and some layers of the integument parenchyma are mainly involved in this process. The outer epidermis cells are highly modified in later stages; their walls are thickened and lignified, creating a unique relatively hard outer coat. The fate of the inner epidermis of integument is completely different. It is separated from the other parenchyma cells of integument and is transformed into an independent new secretory tissue, an endothelium, which fences off the forming embryo and endosperm from the death zone. Due to the secretory activity of the endothelium, the dying inner parenchyma cells of the integument are lysed. Soon after the cuticle covers the endosperm, the lysis of dead integument cells stops and their flattened remnants form dense layers, which then enter the final composition of the coat of mature tomato seed. The endothelium itself returns to the location of the integument inner epidermis.

A digital light microscopic method for diatom surveys using embedded acid-cleaned samples

A digital light microscopic method for diatom surveys using embedded acid-cleaned samples

Morphological analysis and stage determination of anther development in Sorghum [Sorghum bicolor (L.) Moench

Main ConclusionThe characteristics of sorghum anthers at 18 classified developmental stages provide an important reference for future studies on sorghum reproductive biology and abiotic stress tolerance of sorghum pollen.Sorghum (Sorghum bicolor L. Moench) is the fifth-most important cereal crop in the world. It has relatively high resilience to drought and high temperature stresses during vegetative growing stages comparing to other major cereal crops. However, like other cereal crops, the sensitivity of male organ to heat and drought can severely depress sorghum yield due to reduced fertility and pollination efficiency if the stress occurs at the reproductive stage. Identification of the most vulnerable stages and the genes and genetic networks that differentially regulate the abiotic stress responses during anther development are two critical prerequisites for targeted molecular trait selection and for enhanced environmentally resilient sorghum in breeding using a variety of genetic modification strategies. However, in sorghum, anther developmental stages have not been determined. The distinctive cellular characteristics associated with anther development have not been well examined. Lack of such critical information is a major obstacle in the studies of anther and pollen development in sorghum. In this study, we examined the morphological changes of sorghum anthers at cellular level during entire male organ development processes using a modified high-throughput imaging variable pressure scanning electron microscopy and traditional light microscopy methods. We divided sorghum anther development into 18 distinctive stages and provided detailed description of the morphological changes in sorghum anthers for each stage. The findings of this study will serve as an important reference for future studies focusing on sorghum physiology, reproductive biology, genetics, and genomics.

Nanocarriers Made of Proteins: Intracellular Visualization of a Smart Biodegradable Drug Delivery System.

This work analyzes the intracellular fate of protein-based nanocarriers along their endolysosomal pathway by means of correlative light and electron microscopy methods. To unambiguously identify the nanocarriers and their degradation remnants in the cellular environment, they are labeled with fluorescent, inorganic nanoplatelets. This allows tracking the nanocarriers on their intracellular pathway by means of electron microscopy imaging. From the present data, it is possible to identify different cell compartments in which the nanocarriers are processed. Finally, three different terminal routes for the intracellular destiny of the nanocarriers are presented. These findings are important to reveal the degradation process of protein nanocapsules and contribute to the understanding of the therapeutic success of an encapsulated drug.

Microstructure and properties of surface-treated Timetal 834

Abstract Microstructure as well as micro-mechanical and tribological properties of hard surface layers formed on Timetal 834 alloy during its nitridation or oxynitridation under glow discharge were investigated. The tests show that both layers exhibited higher microhardness and Young’s modulus as well as much better wear resistance than the untreated alloy. The microstructure investigations, performed by light microscopy and analytical transmission electron microscopy methods, show that improved micro-mechanical and tribological properties of surface-treated alloy are related to the presence of a multiphase micro/nanostructure containing several sublayers with different morphologies and composition.

Integrated microfluidic device to monitor unseen Escherichia coli contamination in mammalian cell culture

Microbial contamination in in vitro cell culture technologies is a common problem endangering the reliability of the collected data and biosafety of the biological products. Conventionally, microbial contamination can be detected by monitoring the pH and turbidity of cell culture media when using light microscope and/or molecular probes. These methods have limitations such as incompatibility with some cell lines, requirement for human intervention, and long experimental times. Here we present a new integrated microfluidic device (IMD) for the detection of the presence of Escherichia coli (E. coli) in benign prostatic hyperplasia (BPH-1) cell culture. Cell culture media acidity was monitored using an optofluidic sensor, and the cellular glucose metabolism using an electrochemical sensor having in-line continuous monitoring capability. Using this IMD, detection of a bacterial contamination at stages in which it is undetectable using a light microscope and plate counting methods is achieved. Additionally, since even the short-term (less than 8 h) presence of E. coli can change the cellular metabolism in the long term (at least up to 24 h), the use of non-invasive continuous cell culture monitoring platforms significantly reduce the risk of an undetected contamination, increasing the reliability of the conducted experiments with no interference to the cell culture process.

Evaluation of Multiplex/Nested Polymerase Chain Reaction and Loop-Mediated Isothermal Amplification for Malaria Diagnosis in Southeastern Iran.

Malaria is one of the most serious health problems in many countries, including Iran. Accurate diagnosis is important regardless of the elimination status of a country. A cross-sectional study was performed on 105 people who were suspected to be positive for malaria infection in Sistan and Baluchistan, Iran. Blood smears (thin and thick films) were stained with 10% Giemsa. DNA was extracted from the prepared thin and thick films for molecular methods. Multiplex/nested polymerase chain reaction (mn-PCR), loop-mediated isothermal amplification (LAMP), and light microscopy (LM) were compared with nested PCR (nPCR) as a gold standard. Of 105 subjects, 52 (49.5%), 58 (55.2%), 58 (55.2%), and 63 (60%) were positive for malaria by LM, nPCR, mn-PCR, and LAMP, respectively. The sensitivity, specificity, and kappa were 92.1%, 100%, and 0.9 for LAMP and 100%, 100%, and 1 for mn-PCR, respectively. Eight cases of coinfection (Plasmodium vivax and Plasmodium falciparum) that were not detected by LM method were diagnosed by mn-PCR and LAMP. In the present study, the high sensitivity and specificity of LAMP and mn-PCR indicate that these two tests are good alternatives to nPCR for malaria diagnosis.

Germination and seed quality of <i>Perilla frutescens</i> (L.) Britton during introduction in the Southern Coast of the Crimea

Morphological features were revealed and the seed quality of samples of shrubby perilla ( Perilla frutescens (L.) Britton) was determined when introduced to the Southern coast of the Crimea in a subtropical climate of the Mediterranean type. It is shown that samples of various geographical origin under the conditions of introduction undergo all cycles of development, are characterized by high variability of morphological parameters and aroma; form full-fledged seeds with high laboratory (79-92%) and field (75-90%) germination. The application of the X-ray method showed that the seeds have a high degree of completion (57-95%), correlated with germination. The mass of 1000 seeds of the studied samples varies from 1.25 to 1.86 g. The use of light microscopy methods allowed us to study the size, shape, color and surface pattern of the seeds, and to establish that the length of the seeds of shrubby perilla of its own reproduction varies within 1.44-2.23 mm, width - 1.33-1.89 mm. It was found that the seeds of the studied samples have a similar plan of structure: they are characterized by a rounded or oval shape, the surface of the shell has a cellular structure, is colored brown in various shades.

Effects of Moderate Drought on Leaf Bulliform Cells of Aquatic and Coastal Population of Phragmites australis

Studying leaves of aquatic and terrestrial populations of Phragmites australis grown on the bank of the Venetian strait of the Dnipro River in Kyiv (Ukraine) for establishing the role of bulliform cells in the mechanisms of plant resistance to moderate soil drought were studied. Bulliform (motor) cells participate in the twisting and folding of leaves during drought and strong sunlight. The study of bulliform cells in the leaves of the aquatic and terrestrial populations of P. australis was carried out using the methods of light microscopy, cytochemical methods, laser confocal microscopy, and biochemical methods. The comparative analysis of the structure of bulliform cells of leaves of P. australis has shown significant differences depending on plant growth location. The differences in the number, size, and area of bulliform cells and also polysaccharide content showed clear phenotypical plasticity. Cytochemical and laser confocal microscopic studies of polysaccharides of cell walls in bulliform cells of aquatic and terrestrial ecotypes of P. australis showed that a decrease in soil moisture in a natural moderate drought of soil led to an increase in lignin and syringyl monolignol content in the outer walls of bulliform cells and also to a decrease in cellulose and callose content in outer and inner cell walls. The obtained data shows that the studied signs of bulliform cells can be markers of tolerance for population plants that have the ability to curl leaves for the preservation of optimal water balance in moderate drought.

Fossil papilionoids of the Bowdichia clade (Leguminosae) from the Paleogene of North America.

PremiseUnderstanding the evolutionary history of flowering plants has been enriched by the integration of molecular phylogenies and evidence from the fossil record. Fossil fruits and leaves from the late Paleocene and Eocene of Wyoming and Eocene of Kentucky and Tennessee are described as extinct genera in the tropical American Bowdichia clade of the legume subfamily Papilionoideae. Recent phylogenetic study and taxonomic revision of the Bowdichia clade have facilitated understanding of relationships of the fossil taxa and their evolutionary implications and paleoenvironmental significance.MethodsThe fossils were studied using standard methods of specimen preparation and light microscopy and compared to fruits and leaves from extant legume taxa using herbarium collections. Phylogenetic relationships of the fossil taxa were assessed using morphology and DNA sequence data.ResultsTwo new fossil genera are described and their phylogenetic relationships are established. Paleobowdichia lamarensis is placed as sister to the extant genus Bowdichia and Tobya claibornensis is placed with the extant genera Guianodendron and Staminodianthus.ConclusionsThese fossils demonstrate that the tropical American Bowdichia clade was present in North America during a period when tropical or subtropical conditions prevailed in the northern Rocky Mountains during the late Paleocene and the Mississippi Embayment during the middle Eocene. These fossils also document that the Bowdichia clade had diversified by the late Paleocene when the fossil record of the family is relatively sparse. This result suggests that future work on early fossil legumes should focus on tropical and subtropical climatic zones, wherever they may occur latitudinally.

A Next Generation of Advances in Chromosome Architecture.

New insight into the architecture of chromosomes, their molecular composition, structure and spatial location, and time-resolved features, has grown enormously through developments of a range of pioneering interdisciplinary approaches that lie at the interface of the life and physical sciences. These involve several state-of-the-art "physics of life" tools that are both experimental and theoretical, used in conjunction with molecular biology methods which enable investigation of chromosome structure and function in vitro, in vivo, and even in silico. In particular, a move towards far greater quantitation has enabled transformative leaps in our understanding. These have involved valuable improvements to the spatial and temporal resolution of quantitative measurements, such as in vivo super-resolved light microscopy and single-molecule biophysics methods, which facilitate probing of dynamic chromosome processes hitherto impossible. Similarly, there have been important advances in the theoretical biophysics approaches which have enabled advances in predictive modeling to generate new understanding of the modes of operation of chromosomes across all domains of life. Here, I discuss these advances, and review the current state of our knowledge of chromosome architecture and speculation where future advances may lead.

Augmenting Peripheral Nerve Regeneration Using Hair Follicle Stem Cells in Rats.

Cell therapy is the most advanced treatment of peripheral nerve injury. This study aimed to determine the effects of transplantation of hair follicle stem cells on the regeneration of the sciatic nerve injury in rats. The bulge region of the rat whisker were isolated and cultured. Morphological and biological features of the cultured bulge cells were observed by light microscopy and immunocytochemistry methods. Percentages of CD34, K15, and nestin cell markers expression were demonstrated by flow cytometry. Rats were randomly divided into 3 groups of injury, epineurium, and epineurium with cells in which rat Hair Follicular Stem Cells (rHFSCs) were injected into the site of the nerve cut. HFSCs were labeled with Bromodeoxyuridine (BrdU), and double-labeling immunofluorescence was performed to study the survival and differentiation of the grafted cells. After 8 weeks, electrophysiological, histological, and immunocytochemical analysis assessments were performed. Rat hair follicle stem cells are suitable for cell culture, proliferation, and differentiation. The results suggest that transplantation of rat hair follicle stem cells can regenerate sciatic nerve injury; moreover, electrophysiology and histology examinations show that sciatic nerve repair was more effective in the epineurium with cell group than in the other experimental group (P<0.05). The achieved results propose that hair follicle stem cells improve axonal growth and functional recovery after peripheral nerve injury. This study showed that rat hair follicle stem cells are suitable for cell culture, proliferation and differentiationThe results suggested that transplantation of rat hair follicle stem cells had the potential capability of regenerating sciatic nerve injuryEvidence of electrophysiology and histology showed Concomitant use of epineurium with hair follicle stem cell was more effective repairment. Although repairing damaged peripheral nerves has always been a medical challenge, but peripheral nerve injury has been successfully repaired using various procedures such as nerve auto-graft or stem cell therapy. The functional reconstruction is the most important after therapy because of that primary nerve repair or use of nerve autograft, are still accepted as golden standard methods for treatment. Considerable recent interest has been focused on adult stem cells for both research and clinical applications. A highly promising source of relatively abundant and accessible, active, multipotent adult stem cells are obtained from hair follicles. In research the hair follicle stem cells implanted into the gap region of a severed sciatic nerve injury greatly enhanced the rate of nerve regeneration and the restoration of nerve function. Time is one of the several aspects require specific attention in the clinical treatment of peripheral nerve injury. Because delay of nerve injury treatment may cause neurobiological alterations in neurons and Schwann cells, impairing nerve functional recovery and affect neuron survival. In this study, concluded that stem cell injection 2 weeks after injury in the damaged nerve epineurium repairs nerve fibers, while electrophysiology of the leg muscles showed that muscle function was significantly improved. It indicates the repair of muscular innervation and nerve repair. The results pave the way for further research on this topic.

Chloroidium saccharophilum (Chlorophyta) с побережья озера Байкал (Республика Бурятия, Россия)

The article provides information about green microalga Chloroidium saccharophilum (Trebouxiophyceae) whose history of study dates back to more than 100 years. The issues of its intraspecific variability are considered. We also studied the strain of C. saccharophilum IRK–A 230 isolated from a small puddle on the southeastern shore of Lake Baikal (Republic of Buryatia, Russia). Light and electron microscopy and molecular phylogeny methods establish the species identity of the strain. The alga has an ellipsoidal cell shape, parietal chloroplast and visible pyrenoid with starch sheath; reproduction by equal and unequal autospores in even and odd numbers; the ability to form spherical cells; and accumulated yellow pigments in old non-heterotrophic cultures. The data obtained by us complement the species characteristics, and its biology and geography. The amended description of C. saccharophilum is provided.

Surface Structure Analysis of X12CrNiMoV12-3 and X6CrNiTi18-10 Steel Samples Processed by Laser Shot Peening (LSP)

The aim of the experiment was to verify the influence of the chosen strategy of laser shot peening (LSP) on the structure and surface properties of samples made of martensitic steel X12CrNiMo12 and austenitic steel X6CrNiTi18-10. The analyses performed consisted of surface topography analysis of the samples, using a confocal microscope, Olympus LEX|T OLS 5000 and metallographic analysis using a Carl Zeiss Observer Z1m light microscope and a Tescan Mira 3 scanning electron microscope. The metallographic analysis was complemented by the measurement of microhardness HV0.01, which was performed using a Struers DuraScan semi-automatic hardness tester. The LSP process introduced plastic deformation into the surface layer of both materials analysed. The plasma and shock wave generated during the process further affected the surface roughness of both tested materials, which was reflected by an increase in the value of the roughness parameter Rz. Microhardness measurements showed that the influence of the LSP process can increase the surface hardness of the material. Metallographic analysis using light microscopy methods failed to identify differences between the structure near the shot peened surface and the non-peened surface, probably due to the coarse grain structure of both materials analysed.

Cytomorphology of the wound healing process in the green filamentous algae, Ulothrix zonata (F. Weber &amp; Mohr) K tzing 1833

Abstract. For the first time, we present a cytomorphological description of the self-healing (repair) process of damaged thalli sites, wound healing , in the green filamentous algae, Ulothrix zonata (F. Weber &amp; Mohr) K tzing 1833. In the filaments of this species from Lake Baikal and the Angara (Baikal outflow), Zhilishche (Baikal inflow) and Ida (Angara inflow) rivers, light microscopy methods revealed dome-like and conical protrusions and elongations of transverse cell walls directed into adjacent dead (without protoplast) and defective (with deformed chloroplasts) cells. At the same time, there were mostly patterns where two cells formed protrusions directed into the same damaged filament site between them, i.e. towards each other. The growth of previously unconnected cells towards each other led to their convergence and adjacency. This had two important physiological consequences that ensured the restoration of the filament integrity. The first consequence was the formation of intercellular junctions. The second one was the fusion of the protoplasts and nuclei of the adjacent cells (cell fusion) with the formation of vegetative polyploid cells with increased size. During subsequent divisions of these cells, extended areas emerged with a two- to three-fold increase in the diameter of the algal filaments. It was also found that the process of wound healing promoted the development of giant hypnospores. We showed that the H-shaped septa between cells of filamentous algae were not thickenings of the outer walls but the sheaths of the dead cells preserved after this reparation process. Analysis of the wound healing patterns revealed that the Ulothrix cell nuclei did not migrate to the polarized regions of the cells but retained their central position, which testifies to their fixation in the protoplast. We observed sporadic cases of the development of lateral filaments in U. zonata were due to the self-repair of defective cells and their subsequent division during wound healing . A comparison of various cell deformations allowed us to determine the characteristic stages of the wound healing process in U. zonata, which have some similarities and differences with those in marine red filamentous algae. Our study indicates that wound healing is an evolutionarily developed and genetically programmed adaptation that may be widespread in the population of filamentous algae.

Super-resolution confocal cryo-CLEM with cryo-FIB milling for in situ imaging of Deinococcus radiodurans.

Studying bacterial cell envelope architecture with electron microscopy is challenging due to the poor preservation of microbial ultrastructure with traditional methods. Here, we established and validated a super-resolution cryo-correlative light and electron microscopy (cryo-CLEM) method, and combined it with cryo-focused ion beam (cryo-FIB) milling and scanning electron microscopy (SEM) volume imaging to structurally characterize the bacterium Deinococcus radiodurans. Subsequent cryo-electron tomography (cryo-ET) revealed an unusual diderm cell envelope architecture with a thick layer of peptidoglycan (PG) between the inner and outer membranes, an additional periplasmic layer, and a proteinaceous surface S-layer. Cells grew in tetrads, and division septa were formed by invagination of the inner membrane (IM), followed by a thick layer of PG. Cytoskeletal filaments, FtsA and FtsZ, were observed at the leading edges of constricting septa. Numerous macromolecular complexes were found associated with the cytoplasmic side of the IM. Altogether, our study revealed several unique ultrastructural features of D. radiodurans cells, opening new lines of investigation into the physiology and evolution of the bacterium.