The long-term dynamics of serum antibodies against SARS-CoV-2.

Objective: To analyze the long-term dynamics of antibodies against SARS-CoV-2 and understand the impact of age, gender, and viral load on patients' immunological response. Methods: Serum samples were obtained from 231 COVID-19 positive patients from Macaé, in Rio de Janeiro state, in Brazil, from June 2020 until January 2021. The production of IgA, IgM, IgG, and IgE against S glycoprotein was analyzed using the S-UFRJ assay, taking into account the age, gender, and viral load. Results: Analysis of antibody production over 7 months revealed that IgA positivity gradually decreased after the first month. Additionally, the highest percentage of IgM positivity occurred in the first month (97% of patients), and declined after this period, while IgG positivity remained homogeneous for all 7 months. The same analysis for IgE revealed that almost all samples were negative. The comparison of antibody production between genders showed no significant difference. Regarding the age factor and antibody production, patients aged ≥60 years produced almost twice more IgA than younger ones (17-39 years old). Finally, a relationship between viral load and antibody production was observed only for older patients. Conclusions: Our work provides an overview of long-term production of antibodies against SARS-CoV-2, suggesting prolonged production of IgA and IgM antibodies for 3 months and continued IgG production for over 7 months. In addition, it identified a correlation between viral load and IgM titers in the older group and, finally, different IgA production between the age groups.

Molecular testing and analysis of disease spreading during the emergence of COVID-19 in Macaé, the Brazilian National Capital of Oil.

The Brazilian strategy to overcome the spread of COVID-19 has been particularly criticized due to the lack of a national coordinating effort and an appropriate testing program. Here, a successful approach to control the spread of COVID-19 transmission is described by the engagement of public (university and governance) and private sectors (hospitals and oil companies) in Macaé, state of Rio de Janeiro, Brazil, a city known as the National Oil Capital. In 2020 between the 17th and 38th epidemiological week, over two percent of the 206,728 citizens were subjected to symptom analysis and RT-qPCR testing by the Federal University of Rio de Janeiro, with positive individuals being notified up to 48 h after swab collection. Geocodification and spatial cluster analysis were used to limit COVID-19 spreading in Macaé. Within the first semester after the outbreak of COVID-19 in Brazil, Macaé recorded 1.8% of fatalities associated with COVID-19 up to the 38th epidemiological week, which was at least five times lower than the state capital (10.6%). Overall, considering the successful experience of this joint effort of private and public engagement in Macaé, our data suggest that the development of a similar strategy countrywise could have contributed to a better control of the COVID-19 spread in Brazil. Quarantine decree by the local administration, comprehensive molecular testing coupled to scientific analysis of COVID-19 spreading, prevented the catastrophic consequences of the pandemic as seen in other populous cities within the state of Rio de Janeiro and elsewhere in Brazil.

Dermatan sulfate obtained from the Phallusia nigra marine organism is responsible for antioxidant activity and neuroprotection in the neuroblastoma-2A cell lineage.

Neurodegenerative diseases are characterized by progressive loss of neurons in the central nervous system (CNS). Several molecules play a role in mammalian CNS regeneration, including glycosaminoglycans (GAGs). GAGs are found in abundance in many marine invertebrates, such as ascidians that belong to the phylum Chordata, which show a high CNS regeneration capacity even in adulthood. Here, we investigated the roles of dermatan sulfate, a type of GAG that was obtained from the ascidian Phallusia nigra. We investigated the neuroprotective and antioxidant properties of Phallusia nigra dermatan sulfate (PnDS) after neurotoxic damage induced by the pesticide rotenone using the Neuro-2A cell lineage. Neuroprotection was observed through a mitochondrial activity analysis. A morphometric analysis revealed long unbranched neurites after incubation with PnDS and co-incubation with PnDS and rotenone. Furthermore, PnDS showed antioxidant activity that reduced reactive oxygen species (ROS) even in co-incubation with rotenone. The reduced ROS probably occurred because PnDS increased the activity of the antioxidant enzymes superoxide dismutase and catalase and improved total antioxidant capacity, which protected cells from damage, as observed through decreased levels of lipid peroxidation. These data suggest a neuroprotective and antioxidant role of PnDS even under neurodegenerative conditions caused by rotenone.

Diabetic rats present higher urinary loss of proteins and lower renal expression of megalin, cubilin, ClC-5, and CFTR.

Diabetic nephropathy (DN) occurs in around 40% of those with diabetes. Proteinuria is the main characteristic of DN and develops as a result of increased permeability of the glomerulus capillary wall and/or decreased proximal tubule endocytosis. The goal of this work was to evaluate renal function and the expression of megalin, cubilin, CFTR (cystic fibrosis transmembrane conductance regulator), and ClC-5 in the proximal tubule and renal cortex of rats with type 1 diabetes. Male Wistar rats were randomly assigned to control (CTRL) and diabetic (DM) groups for 4 weeks. Renal function was assessed in 24-h urine sample by calculating clearance and fractional excretion of solutes. The RNA and protein contents of ClC-5, CFTR, megalin, and cubilin were determined in the renal proximal tubule and cortex using real-time polymerase chain reaction and western blotting techniques, respectively. The results showed higher creatinine clearance and higher urinary excretion of proteins, albumin, and transferrin in the DM group than in the CTRL group. Furthermore, the renal cortex and proximal tubule of diabetic animals showed downregulation of megalin, cubilin, ClC-5, and CFTR, critical components of the endocytic apparatus. These data suggest dysfunction in proximal tubule low-molecular-weight endocytosis and protein glomerulus filtration in the kidney of diabetic rats.

Cardiopulmonary Performance During Maximal Exercise in Soccer Players with Alterations in Renal Function.

The aim of this study was to evaluate the curves of cardiorespiratory variables during cardiopulmonary exercise testing (CPET) in soccer players who had acute alterations in the glomerular filtration rate (GFR) after performing the pre-season training protocol. Sixteen male professional soccer players (25 ± 3 years; 179 ± 2 cm; and 77 ± 6 kg) were evaluated for oxygen uptake (VO2), heart rate (HR) and pulse relative oxygen (relative O2 Pulse) curves with intervals corresponding to 10% of the total duration of CPET. Athletes were grouped according to the GFR and classified as decreased GFR (dGFR; n = 8) and normal GFR (nGFR; n = 8). Athletes from the dGFR group exhibited lower VO2 values (p < 0.05) when 90% (dGFR 49.8 ± 4.0 vs. nGFR 54.4 ± 6.1 ml·kg-1·min-1) and 100% (dGFR 52.6 ± 4.1 vs. nGFR 57.4 ± 5.9 ml·kg-1·min-1) of the test was complete; HR high values (p < 0.05) when 90% (dGFR 183.7 ± 5.1 vs. nGFR 176.6 ± 4.8 bpm-1) and 100% (dGFR 188.1 ± 5.0 vs. nGFR 180.8 ± 4.8 bpm-1) of the test was complete; and lower relative O2 Pulse values (p < 0.05) when 70% (dGFR 25.6 ± 8.4 vs. nGFR 27.9 ± 9.7 ml·beat-1·kg-1), 80% (dGFR 26.6 ± 8.8 vs. nGFR 29.1 ± 10.0 ml·beat-1·kg-1), 90% (dGFR 27.1 ± 9.0 vs. nGFR 30.8 ± 10.6 ml·beat-1·kg-1) and 100% (dGFR 28 ± 9.2 vs. nGFR 31.8 ± 10.9 ml·beat-1·kg-1) of the test was complete. A correlation was found (r = -0.66, R2 = 0.44, p = 0.00) between lower VO2 peak and elevated levels of urinary protein excretion. In conclusion, soccer players with reduced kidney function after performing the pre-season training protocol also presented alterations in cardiopulmonary variables. We suggest that monitoring of renal function may be used to identify less conditioned soccer players.

Evolution and multiple roles of the Pancrustacea specific transcription factor zelda in insects.

Gene regulatory networks (GRNs) evolve as a result of the coevolutionary processes acting on transcription factors (TFs) and the cis-regulatory modules they bind. The zinc-finger TF zelda (zld) is essential for the maternal-to-zygotic transition (MZT) in Drosophila melanogaster, where it directly binds over thousand cis-regulatory modules to regulate chromatin accessibility. D. melanogaster displays a long germ type of embryonic development, where all segments are simultaneously generated along the whole egg. However, it remains unclear if zld is also involved in the MZT of short-germ insects (including those from basal lineages) or in other biological processes. Here we show that zld is an innovation of the Pancrustacea lineage, being absent in more distant arthropods (e.g. chelicerates) and other organisms. To better understand zld´s ancestral function, we thoroughly investigated its roles in a short-germ beetle, Tribolium castaneum, using molecular biology and computational approaches. Our results demonstrate roles for zld not only during the MZT, but also in posterior segmentation and patterning of imaginal disc derived structures. Further, we also demonstrate that zld is critical for posterior segmentation in the hemipteran Rhodnius prolixus, indicating this function predates the origin of holometabolous insects and was subsequently lost in long-germ insects. Our results unveil new roles of zld in different biological contexts and suggest that changes in expression of zld (and probably other major TFs) are critical in the evolution of insect GRNs.

Glycogen and glucose metabolism are essential for early embryonic development of the red flour beetle Tribolium castaneum.

Control of energy metabolism is an essential process for life. In insects, egg formation (oogenesis) and embryogenesis is dependent on stored molecules deposited by the mother or transcribed later by the zygote. In oviparous insects the egg becomes an isolated system after egg laying with all energy conversion taking place during embryogenesis. Previous studies in a few vector species showed a strong correlation of key morphogenetic events and changes in glucose metabolism. Here, we investigate glycogen and glucose metabolism in the red flour beetle Tribolium castaneum, an insect amenable to functional genomic studies. To examine the role of the key enzymes on glycogen and glucose regulation we cloned and analyzed the function of glycogen synthase kinase 3 (GSK-3) and hexokinase (HexA) genes during T. castaneum embryogenesis. Expression analysis via in situ hybridization shows that both genes are expressed only in the embryonic tissue, suggesting that embryonic and extra-embryonic cells display different metabolic activities. dsRNA adult female injection (parental RNAi) of both genes lead a reduction in egg laying and to embryonic lethality. Morphological analysis via DAPI stainings indicates that early development is impaired in Tc-GSK-3 and Tc-HexA1 RNAi embryos. Importantly, glycogen levels are upregulated after Tc-GSK-3 RNAi and glucose levels are upregulated after Tc-HexA1 RNAi, indicating that both genes control metabolism during embryogenesis and oogenesis, respectively. Altogether our results show that T. castaneum embryogenesis depends on the proper control of glucose and glycogen.

Thyroid hormones stimulate renal expression of CFTR.

CFTR is a multifunctional protein of the ATP binding cassette family that may contribute to overall electrolyte homeostasis by acting as a chloride channel in the kidney. In renal tissues CFTR does not exists only in its full-length form, but also as a kidney-specific, truncated splice variant, TNR-CFTR. In this study we show that both forms of CFTR are regulated by thyroid hormones in rat renal tissue. Four groups of male rats were used: control, hypothyroid, hypothyroid with T(4) treatment and hyperthyroid rats. The hypothyroid rats showed a decrease of both CFTR and TNR-CFTR mRNAs (44%, and 49%, respectively, n=5; p<0.05) and proteins (30% and 37%, respectively, n=5, p<0.05) expressions, compared to control group. In hyperthyroid rats, a significant increase in both CFTR and TRN-CFTR mRNAs expressions (43% and 95%, n=5; p<0.05) and proteins (250% and 38%, respectively, n=5, p<0.05) was observed when compared to control group. Treatment of immortalized rat proximal tubule cells (IRPTC) with T(3) (10(-7)M) produced also an increase of CFTR mRNA expression (95%, n=5, p<0.05). Analysis of the promoter region of CFTR transfected to IRPTC showed that T(3) (10(-7) M) stimulates the CFTR promoter (38%, n=4, p<0.05).

Single-strand conformation polymorphism of hyper-variable regions HV1 and HV2 of human mitochondrial DNA: detection by silver staining.

Human mitochondrial DNA from 50 trios consisting of mother (M), child (C) and father (F) was PCR amplified with primers flanking the hyper-variable regions, HVR1 and HVR2. The amplified products were then fractionated under non-denaturing conditions, silver-stained and compared by single-stranded conformational polymorphism (SSCP). In all but one case, mother and child displayed identical patterns, which could be promptly distinguished from that of the father. For the remaining cases, either set of primers was sufficient to resolve the familial ties. In no instance, M displayed alleles different from those of C within each trio, demonstrating that no false exclusions occurred. The SSCP approach proved to be a robust technique suitable as a preliminary screening in cases requiring identification of multiple samples.