B cell expansion hinders the stroma-epithelium regenerative cross talk during mucosal healing.

Therapeutic promotion of intestinal regeneration holds great promise, but defining the cellular mechanisms that influence tissue regeneration remains an unmet challenge. To gain insight into the process of mucosal healing, we longitudinally examined the immune cell composition during intestinal damage and regeneration. B cells were the dominant cell type in the healing colon, and single-cell RNA sequencing (scRNA-seq) revealed expansion of an IFN-induced B cell subset during experimental mucosal healing that predominantly located in damaged areas and associated with colitis severity. B cell depletion accelerated recovery upon injury, decreased epithelial ulceration, and enhanced gene expression programs associated with tissue remodeling. scRNA-seq from the epithelial and stromal compartments combined with spatial transcriptomics and multiplex immunostaining showed that B cells decreased interactions between stromal and epithelial cells during mucosal healing. Activated B cells disrupted the epithelial-stromal cross talk required for organoid survival. Thus, B cell expansion during injury impairs epithelial-stromal cell interactions required for mucosal healing, with implications for the treatment of IBD.

Gene regulatory network inference in the era of single-cell multi-omics.

The interplay between chromatin, transcription factors and genes generates complex regulatory circuits that can be represented as gene regulatory networks (GRNs). The study of GRNs is useful to understand how cellular identity is established, maintained and disrupted in disease. GRNs can be inferred from experimental data - historically, bulk omics data - and/or from the literature. The advent of single-cell multi-omics technologies has led to the development of novel computational methods that leverage genomic, transcriptomic and chromatin accessibility information to infer GRNs at an unprecedented resolution. Here, we review the key principles of inferring GRNs that encompass transcription factor-gene interactions from transcriptomics and chromatin accessibility data. We focus on the comparison and classification of methods that use single-cell multimodal data. We highlight challenges in GRN inference, in particular with respect to benchmarking, and potential further developments using additional data modalities.

Spatial multi-omic map of human myocardial infarction.

Myocardial infarction is a leading cause of death worldwide1. Although advances have been made in acute treatment, an incomplete understanding of remodelling processes has limited the effectiveness of therapies to reduce late-stage mortality2. Here we generate an integrative high-resolution map of human cardiac remodelling after myocardial infarction using single-cell gene expression, chromatin accessibility and spatial transcriptomic profiling of multiple physiological zones at distinct time points in myocardium from patients with myocardial infarction and controls. Multi-modal data integration enabled us to evaluate cardiac cell-type compositions at increased resolution, yielding insights into changes of the cardiac transcriptome and epigenome through the identification of distinct tissue structures of injury, repair and remodelling. We identified and validated disease-specific cardiac cell states of major cell types and analysed them in their spatial context, evaluating their dependency on other cell types. Our data elucidate the molecular principles of human myocardial tissue organization, recapitulating a gradual cardiomyocyte and myeloid continuum following ischaemic injury. In sum, our study provides an integrative molecular map of human myocardial infarction, represents an essential reference for the field and paves the way for advanced mechanistic and therapeutic studies of cardiac disease.

Assessing the impact of transcriptomics data analysis pipelines on downstream functional enrichment results.

Transcriptomics is widely used to assess the state of biological systems. There are many tools for the different steps, such as normalization, differential expression, and enrichment. While numerous studies have examined the impact of method choices on differential expression results, little attention has been paid to their effects on further downstream functional analysis, which typically provides the basis for interpretation and follow-up experiments. To address this, we introduce FLOP, a comprehensive nextflow-based workflow combining methods to perform end-to-end analyses of transcriptomics data. We illustrate FLOP on datasets ranging from end-stage heart failure patients to cancer cell lines. We discovered effects not noticeable at the gene-level, and observed that not filtering the data had the highest impact on the correlation between pipelines in the gene set space. Moreover, we performed three benchmarks to evaluate the 12 pipelines included in FLOP, and confirmed that filtering is essential in scenarios of expected moderate-to-low biological signal. Overall, our results underscore the impact of carefully evaluating the consequences of the choice of preprocessing methods on downstream enrichment analyses. We envision FLOP as a valuable tool to measure the robustness of functional analyses, ultimately leading to more reliable and conclusive biological findings.

Complementing Cell Taxonomies with a Multicellular Analysis of Tissues.

The application of single-cell molecular profiling coupled with spatial technologies has enabled charting of cellular heterogeneity in reference tissues and in disease. This new wave of molecular data has highlighted the expected diversity of single-cell dynamics upon shared external queues and spatial organizations. However, little is known about the relationship between single-cell heterogeneity and the emergence and maintenance of robust multicellular processes in developed tissues and its role in (patho)physiology. Here, we present emerging computational modeling strategies that use increasingly available large-scale cross-condition single-cell and spatial datasets to study multicellular organization in tissues and complement cell taxonomies. This perspective should enable us to better understand how cells within tissues collectively process information and adapt synchronized responses in disease contexts and to bridge the gap between structural changes and functions in tissues.

Expanding the coverage of regulons from high-confidence prior knowledge for accurate estimation of transcription factor activities.

Gene regulation plays a critical role in the cellular processes that underlie human health and disease. The regulatory relationship between transcription factors (TFs), key regulators of gene expression, and their target genes, the so called TF regulons, can be coupled with computational algorithms to estimate the activity of TFs. However, to interpret these findings accurately, regulons of high reliability and coverage are needed. In this study, we present and evaluate a collection of regulons created using the CollecTRI meta-resource containing signed TF-gene interactions for 1186 TFs. In this context, we introduce a workflow to integrate information from multiple resources and assign the sign of regulation to TF-gene interactions that could be applied to other comprehensive knowledge bases. We find that the signed CollecTRI-derived regulons outperform other public collections of regulatory interactions in accurately inferring changes in TF activities in perturbation experiments. Furthermore, we showcase the value of the regulons by examining TF activity profiles in three different cancer types and exploring TF activities at the level of single-cells. Overall, the CollecTRI-derived TF regulons enable the accurate and comprehensive estimation of TF activities and thereby help to interpret transcriptomics data.

Single-cell transcriptomics reveal distinctive patterns of fibroblast activation in heart failure with preserved ejection fraction.

Inflammation, fibrosis and metabolic stress critically promote heart failure with preserved ejection fraction (HFpEF). Exposure to high-fat diet and nitric oxide synthase inhibitor N[w]-nitro-l-arginine methyl ester (L-NAME) recapitulate features of HFpEF in mice. To identify disease-specific traits during adverse remodeling, we profiled interstitial cells in early murine HFpEF using single-cell RNAseq (scRNAseq). Diastolic dysfunction and perivascular fibrosis were accompanied by an activation of cardiac fibroblast and macrophage subsets. Integration of fibroblasts from HFpEF with two murine models for heart failure with reduced ejection fraction (HFrEF) identified a catalog of conserved fibroblast phenotypes across mouse models. Moreover, HFpEF-specific characteristics included induced metabolic, hypoxic and inflammatory transcription factors and pathways, including enhanced expression of Angiopoietin-like 4 (Angptl4) next to basement membrane compounds, such as collagen IV (Col4a1). Fibroblast activation was further dissected into transcriptional and compositional shifts and thereby highly responsive cell states for each HF model were identified. In contrast to HFrEF, where myofibroblast and matrifibrocyte activation were crucial features, we found that these cell states played a subsidiary role in early HFpEF. These disease-specific fibroblast signatures were corroborated in human myocardial bulk transcriptomes. Furthermore, we identified a potential cross-talk between macrophages and fibroblasts via SPP1 and TNFɑ with estimated fibroblast target genes including Col4a1 and Angptl4. Treatment with recombinant ANGPTL4 ameliorated the murine HFpEF phenotype and diastolic dysfunction by reducing collagen IV deposition from fibroblasts in vivo and in vitro. In line, ANGPTL4, was elevated in plasma samples of HFpEF patients and particularly high levels associated with a preserved global-longitudinal strain. Taken together, our study provides a comprehensive characterization of molecular fibroblast activation patterns in murine HFpEF, as well as the identification of Angiopoietin-like 4 as central mechanistic regulator with protective effects.

Role of the sympathetic nervous system in cancer-associated cachexia and tumor progression in tumor-bearing BALB/c mice.

BACKGROUND: Adipose and muscle tissue wasting outlines the cachectic process during tumor progression. The sympathetic nervous system (SNS) is known to promote tumor progression and research suggests that it might also contribute to cancer-associated cachexia (CAC) energetic expenditure through fat wasting. METHODS: We sympathectomized L5178Y-R tumor-bearing male BALB/c mice by intraperitoneally administering 6-hydroxydopamine to evaluate morphometric, inflammatory, and molecular indicators of CAC and tumor progression. RESULTS: Tumor burden was associated with cachexia indicators, including a 10.5% body mass index (BMI) decrease, 40.19% interscapular, 54% inguinal, and 37.17% visceral adipose tissue loss, a 12% food intake decrease, and significant (p = 0.038 and p = 0.0037) increases in the plasmatic inflammatory cytokines IL-6 and IFN-γ respectively. Sympathectomy of tumor-bearing mice was associated with attenuated BMI and visceral adipose tissue loss, decreased interscapular Ucp-1 gene expression to basal levels, and 2.6-fold reduction in Mmp-9 relative gene expression, as compared with the unsympathectomized mice control group. CONCLUSION: The SNS contributes to CAC-associated morphometric and adipose tissue alterations and promotes tumor progression in a murine model.

Comprehensive analysis of right fascicular and right bundle branch blocks: A multi-center study.

Electrocardiographic patterns of right bundle branch and fascicular blocks were comprehensively analyzed in a two-phase study. The research aimed to address the scarcity of literature and the absence of standardized diagnostic criteria for these conditions. It revealed a weak correlation between the cardiac axis and age and highlighted the high misdiagnosis rate of these blocks. Furthermore, it discussed the challenges in fulfilling existing diagnostic criteria. The study emphasizes the need for a more precise understanding of right ventricular conduction disorders and the importance of developing robust diagnostic criteria.

Intra-Phenotypic and -Genotypic Variations of Beauveria bassiana (Bals.) Vuill. Strains Infecting Aedes aegypti L. Adults.

Beauveria bassiana has potential for Aedes aegypti biological control. However, its efficacy depends on the strain's geographic location, host susceptibility, and virulence. The present study aimed to evaluate the effectiveness of B. bassiana strain BBPTG4 conidia in controlling Ae. aegypti adults and its detection via introns profile on exposed mosquito corpses. Morphologic characteristics among strains were highly similar. Comprehensive testing of these strains demonstrated that BBPT4 exhibited the ideal biological activity for Ae. aegypti control, with a median lethal time (TL50) of 7.5 d compared to ~3 d and ~10 d for BB01 and BB37 strains, respectively. Infected mosquitoes died after GHA and BBPTG4 exposure, and corpses were analyzed for infecting strains detection. Differences among the seven evaluated strains were determined, assessing five different insertion group I intron profiles in BBTG4, BB01, GHA, BB37, and BB02 strains. Mosquitoes infected by BBPTG4 and non-exposed (negative control) intron profiles were obtained. We detected the presence of introns in the BBPTG4 strain, which were not present in non-exposed mosquitoes. In conclusion, B. bassiana strains showed similarities in terms of their cultural and microscopic morphological characteristics and biologicals virulence level, but different intron profiles. BBPTG4 strain-infected Ae. aegypti adult corpses, showing specific amplicons, enabled us to identify B. bassiana at the strain level among infected mosquitoes. However, monitoring and detection of field-infected insects is essential for further verification.

Bifidobacterium longum and Chlorella sorokiniana Combination Modulates IFN-γ, IL-10, and SOCS3 in Rotavirus-Infected Cells.

Rotavirus is the main cause of acute diarrhea in children up to five years of age. In this regard, probiotics are commonly used to treat or prevent gastroenteritis including viral infections. The anti-rotavirus effect of Bifidobacterium longum and Chlorella sorokiniana, by reducing viral infectivity and improving IFN-type I response, has been previously reported. The present study aimed to study the effect of B. longum and/or C. sorokiniana on modulating the antiviral cellular immune response mediated by IFN-γ, IL-10, SOCS3, STAT1, and STAT2 genes in rotavirus-infected cells. To determine the mRNA relative expression of these genes, HT-29 cells were treated with B. longum and C. sorokiniana alone or in combination, followed by rotavirus infection. In addition, infected cells were treated with B. longum and/or C. sorokiniana. Cellular RNA was purified, used for cDNA synthesis, and amplified by qPCR. Our results demonstrated that the combination of B. longum and C. sorokiniana stimulates the antiviral cellular immune response by upregulating IFN-γ and may block pro-inflammatory cytokines by upregulating IL-10 and SOCS3. The results of our study indicated that B. longum, C. sorokiniana, or their combination improve antiviral cellular immune response and might modulate pro-inflammatory responses.

MiR-21 Regulates Growth and Migration of Cervical Cancer Cells by RECK Signaling Pathway.

Expression of miR-21 has been found to be altered in almost all types of cancers, and it has been classified as an oncogenic microRNA. In addition, the expression of tumor suppressor gene RECK is associated with miR-21 overexpression in high-grade cervical lesions. In the present study, we analyze the role of miR-21 in RECK gene regulation in cervical cancer cells. To identify the downstream cellular target genes of upstream miR-21, we silenced endogenous miR-21 expression using siRNAs. We analyzed the expression of miR-21 and RECK, as well as functional effects on cell proliferation and migration. We found that in cervical cancer cells, there was an inverse correlation between miR-21 expression and RECK mRNA and protein expression. SiRNAs to miR-21 increased luciferase reporter activity in construct plasmids containing the RECK-3'-UTR microRNA response elements MRE21-1, MRE21-2, and MRE21-3. The role of miR-21 in cell proliferation was also analyzed, and cancer cells transfected with siRNAs exhibited a markedly reduced cell proliferation and migration. Our findings indicate that miR-21 post-transcriptionally down-regulates the expression of RECK to promote cell proliferation and cell migration inhibition in cervical cancer cell survival. Therefore, miR-21 and RECK may be potential therapeutic targets in gene therapy for cervical cancer.

Novices' learning curve in single-port surgery using three surgical training programs.

BACKGROUND: The objective of this study was to evaluate the novices' learning curves and proficiency level reached in laparoendoscopic single-site (LESS) surgery using three surgical training programs. MATERIAL AND METHODS: Participants were randomly divided into three groups, who trained in a specific practice regimen for 12 days using a laparoscopic box simulator and three tasks. Group A trained in three stages using conventional laparoscopic surgery (CLS) with straight instruments, and LESS with straight and articulating instruments for four days each. Group B trained in two stages in LESS with straight and articulating instruments for six days each. Group C trained only in LESS with articulating instruments exclusively for all 12 days. Performance was registered daily during the 12 days to evaluate the participants' progress. RESULTS: Pre- and post-training analysis of the three groups showed significant differences in performance, denoting the significant improvement in their LESS skills, with no difference between the groups. Group C reached a high level of technical competence with their specific training program in LESS, obtaining a lower asymptote and slow learning rate. CONCLUSION: Specific training programs in LESS settings using articulated instruments showed a slower learning rate than the other programs but better proficiency in the technique with the best surgical performance.

Expression of symptoms elicited by a hammerhead viroid through RNA silencing is related to population bottlenecks in the infected host.

Chlorosis is frequently incited by viroids, small nonprotein-coding, circular RNAs replicating in nuclei (family Pospiviroidae) or chloroplasts (family Avsunviroidae). Here, we investigated how chrysanthemum chlorotic mottle viroid (CChMVd, Avsunviroidae) colonizes, evolves and initiates disease. Progeny variants of natural and mutated CChMVd sequence variants inoculated in chrysanthemum plants were characterized, and plant responses were assessed by molecular assays. We showed that: chlorotic mottle induced by CChMVd reflects the spatial distribution and evolutionary behaviour in the infected host of pathogenic (containing a UUUC tetranucleotide) and nonpathogenic (lacking such a pathogenic determinant) variants; and RNA silencing is involved in the initiation of the chlorosis in symptomatic leaf sectors through a viroid-derived small RNA containing the pathogenic determinant that directs AGO1-mediated cleavage of the mRNA encoding the chloroplastic transketolase. This study provides the first evidence that colonization of leaf tissues by CChMVd is characterized by segregating variant populations differing in pathogenicity and with the ability to colonize leaf sectors (bottlenecks) and exclude other variants (superinfection exclusion). Importantly, no specific pathogenic viroid variants were found in the chlorotic spots caused by chrysanthemum stunt viroid (Pospiviroidae), thus establishing a clear distinction on how members of the two viroid families trigger chlorosis in the same host.

Objective psychomotor laparoscopic skills evaluation using a low-cost wearable device based on accelerometry: construct and concurrent validity study.

BACKGROUND: Motion analysis of surgical maneuvers provides useful quantitative information for the objective evaluation of the surgeons. However, surgical simulation laboratories for laparoscopic training do not usually integrate devices that help quantify the level of skills of the surgeons due to their limited resources and the high costs of new technologies. The purpose of this study is to present the construct and concurrent validity of a low-cost motion tracking system, based on a wireless triaxial accelerometer, employed to objectively evaluate psychomotor skills of surgeons during laparoscopic training. METHODS: An accelerometry system, a wireless three-axis accelerometer with appearance of wristwatch, was placed on the dominant hand of the surgeons to register the motion during the laparoscopy practice with the EndoViS simulator, which simultaneously recorded the motion of the laparoscopic needle driver. This study included the participation of 30 surgeons (6 experts, 14 intermediates and 10 novices) who performed the task of intracorporeal knot-tying suture. Using 11 motion analysis parameters (MAPs), the performance of each participant was assessed. Subsequently, the scores of the three groups of surgeons were statistically analyzed. In addition, a validity study was conducted comparing the metrics between the accelerometry-tracking system and the EndoViS hybrid simulator. RESULTS: Construct validity was achieved for 8 of the 11 metrics examined with the accelerometry system. Concurrent validity demonstrated that there is a strong correlation between the results of the accelerometry system and the EndoViS simulator in 9 of 11 parameters, showing reliability of the accelerometry system as an objective evaluation method. CONCLUSION: The accelerometry system was successfully validated. This method is potentially useful to complement the objective evaluation of surgeons during laparoscopic practice in training environments such as box-trainers and simulators.

Face, content, and construct validity of the virtual immersive operating room simulator for training laparoscopic procedures.

BACKGROUND: The aim of this work is to present the face, content, and construct validation of the virtual immersive operating room simulator (VIORS) for procedural training of surgeons' laparoscopic psychomotor skills and evaluate the immersive training experience. METHODS: The VIORS simulator consists of an HMD Oculus Rift 2016 with a visor on a 1080 × 1200 pixel OLED screen, two positioning sensors with two adapted controls to simulate laparoscopic instruments, and an acrylic base to simulate the conventional laparoscopic setup. The immersion consists of a 360° virtual operating room environment, based on the EndoSuite at Hospital Infantil de Mexico Federico Gomez, which reproduces a configuration of equipment, instruments, and common distractions in the operating room during a laparoscopic cholecystectomy procedure. Forty-five surgeons, residents, and medicine students participated in this study: 27 novices, 13 intermediates, and 5 experts. They completed a questionnaire on the realism and operating room immersion, as well as their capabilities for laparoscopic procedural training, scored in the 5-point Likert scale. The data of instrument movement were recorded and analyzed using 13 movement analysis parameters (MAPs). The experience during training with VIORS was evaluated through NASA-TLX. RESULTS: The participants were enthusiastic about the immersion and sensation levels of the VIORS simulator, with positive scores on the realism and its capabilities for procedural training using VIORS. The results proved that the VIORS simulator was able to differentiate between surgeons with different skill levels. Statistically significant differences were found in nine MAPs, demonstrating their construct validity for the objective assessment of the procedural laparoscopic performance. At cognitive level, the inversion experience proves a moderate mental workload when the laparoscopic procedure is carried out. CONCLUSION: The VIORS simulator has been successfully presented and validated. The VIORS simulator is a useful and effective device for the training of procedural laparoscopic psychomotor skills.

Mitochondrial dysfunction: The pathological link between psoriasis and insulin resistance?

BACKGROUND: Psoriasis is strongly associated with insulin resistance (IR). Lipid profile disturbances and upregulation of enzymes crucial for fatty acid oxidation have been reported in patients with psoriasis. Mitochondrial ß-oxidation is altered in patients with IR. Common mitochondrial dysfunction may be involved in the origin of both diseases. OBJECTIVE: This study aimed to evaluate mitochondrial ß-oxidation, intermediary metabolism, and mitochondrial content in psoriatic patients with or without IR and compare them to healthy controls. METHODS: The participants were divided into three groups: (1) psoriasis and IR (n = 26); (2) psoriasis without IR (n = 17); and (3) healthy controls (n = 17). Quantification of amino acids and acylcarnitines (AC) by tandem mass spectrometry, determination of urinary organic acids by gas chromatography/mass spectrometry (GC/MS), and mitochondrial DNA quantification were performed in all groups. RESULTS: When comparisons were made between the two psoriatic groups, no differences were found between: C5DC + C6OH, C16:1, Met/Leu, Met/Phe, C16:1/C16, and C5DC + C6OH/C4DC + C5OH ratios. Nine analytes were different: phenylalanine, Cit/Phe, and Cit/Tyr ratios, C0, C3, C5, C6DC, C16, and C18:1OH. There were no correlations between psoriasis area and severity index (PASI), body mass index (BMI) and duration of disease with ACs. A higher proportion of patients with psoriasis showed increased urine levels of uric acid and hippuric acid (p = 0.01). The mtDNA content was significantly higher in cases than in controls, with no differences between IR and non-IR psoriatic patients. CONCLUSIONS: Psoriasis patients with and without IR have a different acylcarnitine profile reflecting impaired ß-oxidation. A distinctive profile of acylcarnitines suggests an involvement of mitochondrial function associated with an increase in stearoyl CoA desaturase (SCD) activity in psoriatic patients with and without IR.

Toxoplasma gondii excreted/secreted proteases disrupt intercellular junction proteins in epithelial cell monolayers to facilitate tachyzoites paracellular migration.

Toxoplasma gondii shows high dissemination and migration properties across biological barriers infecting immunologically privileged organs. Toxoplasma uses different routes for dissemination; however, the mechanisms are not fully understood. Herein, we studied the effects of proteases present in excretion/secretion products (ESPs) of Toxoplasma on MDCK cell monolayers. Ultrastructural analysis showed that ESPs of Toxoplasma disrupt the intercellular junctions (IJ) of adjacent cells. The tight junction (TJ) proteins ZO-1, occludin, and claudin-1 suffered a progressive decrease in protein levels upon ESPs treatment. In addition, ESPs induced mislocalization of such TJ proteins, along with the adherent junction protein E-cadherin, and this was prevented by pre-treating the ESPs with protease inhibitors. Reorganisation of cytoskeleton proteins was also observed. Endocytosis inhibitors, Dyngo®-4a and Dynasore, impeded the modifications, suggesting that TJ proteins internalisation is triggered by the ESPs proteases hence contributing to the loss of IJ. The observed disruption in TJ proteins went in line with a decrease in the transepithelial electrical resistance of the monolayers, which was significantly blocked by pre-treating ESPs with metalloprotease and serine protease inhibitors. Moreover, exposure of cell monolayers to ESPs facilitated paracellular migration of tachyzoites. Our results demonstrate that Toxoplasma ESPs contain proteases that can disrupt the IJ of epithelial monolayers and this could facilitate the paracellular route for Toxoplasma tissue dissemination and migration.

Impact of fetal endoscopic tracheal occlusion in fetuses with congenital diaphragmatic hernia and moderate lung hypoplasia.

OBJECTIVE: To assess the effect of Fetal Endoscopic Tracheal Occlusion (FETO) on neonatal survival in fetuses with left congenital diaphragmatic hernia (CDH) and moderate lung hypoplasia. STUDY DESIGN: CDH fetuses with moderate pulmonary hypoplasia (observed/expected lung area to head ratio between 26% and 35%, or between 36% and 45% with liver herniation) were prospectively recruited. Included patients were matched to a control group who were ineligible for FETO. Primary outcomes were survival at 28 days, at discharge, and at 6 months of age, respectively. RESULTS: 58 cases were recruited, 29 treated with FETO and 29 matched controls. Median gestational age (GA) at balloon placement and removal were 29.6 and 33.6 weeks, respectively. FETO group showed significantly lower GA at delivery (35.2 vs. 37.1 weeks, respectively, p < 0.01), higher survival at 28 days (51.7 vs. 24.1%, respectively, p = 0.03), at discharge (48.3 vs. 24.1%, respectively, p = 0.06), and at six months of age (41.4 vs. 24.1%, respectively, p = 0.16), and significantly lower length of ventilatory support (17.8 vs. 32.3 days, p = 0.01) and NICU stay (34.2 vs. 58.3 days, p = <0.01) compared to controls. CONCLUSION: FETO was associated with a non-significant increase in survival and significantly lower neonatal respiratory morbidity among CDH fetuses with moderate lung hypoplasia.

A comprehensive ultrastructural analysis of the Toxoplasma gondii cytoskeleton.

The invasive nature of Toxoplasma gondii is closely related to the properties of its cytoskeleton, which is constituted by a group of diverse structural and dynamic components that play key roles during the infection. Even if there have been numerous reports about the composition and function of the Toxoplasma cytoskeleton, the ultrastructural organization of some of these components has not yet been fully characterized. This study used a detergent extraction process and several electron microscopy contrast methods that allowed the successful isolation of the cytoskeleton of Toxoplasma tachyzoites. This process allowed for the conservation of the structures known to date and several new structures that had not been characterized at the ultrastructural level. For the first time, characterization was achieved for a group of nanofibers that allow the association between the polar apical ring and the conoid as well as the ultrastructural characterization of the apical cap of the parasite. The ultrastructure and precise location of the peripheral rings were also found, and the annular components of the basal complex were characterized. Finally, through immunoelectron microscopy, the exact spatial location of the subpellicular network inside the internal membrane system that forms the pellicle was found. The findings regarding these new structures contribute to the knowledge concerning the biology of the Toxoplasma gondii cytoskeleton. They also provide new opportunities in the search for therapeutic strategies aimed at these components with the purpose of inhibiting invasion and thus parasitism.