An Approach for Engineering Peptides for Competitive Inhibition of the SARS-COV-2 Spike Protein.

SARS-CoV-2 is the virus responsible for a respiratory disease called COVID-19 that devastated global public health. Since 2020, there has been an intense effort by the scientific community to develop safe and effective prophylactic and therapeutic agents against this disease. In this context, peptides have emerged as an alternative for inhibiting the causative agent. However, designing peptides that bind efficiently is still an open challenge. Here, we show an algorithm for peptide engineering. Our strategy consists of starting with a peptide whose structure is similar to the interaction region of the human ACE2 protein with the SPIKE protein, which is important for SARS-COV-2 infection. Our methodology is based on a genetic algorithm performing systematic steps of random mutation, protein-peptide docking (using the PyRosetta library) and selecting the best-optimized peptides based on the contacts made at the peptide-protein interface. We performed three case studies to evaluate the tool parameters and compared our results with proposals presented in the literature. Additionally, we performed molecular dynamics (MD) simulations (three systems, 200 ns each) to probe whether our suggested peptides could interact with the spike protein. Our results suggest that our methodology could be a good strategy for designing peptides.

Immunisation with Neospora caninum subunits rsNcSAG4 and rsNcGRA1 (NcSAG4 and NcGRA1 epitopes construct) in BALB/c mice: the profile of the immune response and controlling the vertical transmission.

Neospora caninum is an apicomplexan protozoan that causes neosporosis, which has a high economic impact on cattle herds with no available vaccine. During infection, the secretion of dense granules and the expression of surface antigens play an important role in hosting immunomodulation. However, some epitopes of those antigens are immunogenic, and using these fractions could improve the subunit antigens in vaccine design. This study evaluates the recombinant peptides rsNcGRA1 and rsNcSAG4 derived from NcGRA1 and NcSAG4 native antigens as vaccine candidates produced by a fermentative process in the yeast culture system of Komagataella phaffii strain Km71, confirmed by colony PCR, SDS-PAGE, and western blotting. The assay was conducted in BALB/c mice using the peptides at low (25 µg) and standard (50 µg) dosages in monovalent and combined administrations at three time points with saponin as an adjuvant assessing the immunogenicity by antibodies response and cytokine production. We challenge the females after pregnancy confirmation using 2 × 105 NC-1 tachyzoites previously propagated in Vero cells. We assessed the chronic infection in dams and vertical transmission in the offspring by PCR and histopathology. Mice, especially those immunised with combined peptides and monovalent rsNcGRA1 at a standard dose, controlling the chronic infection in dams with the absence of clinical manifestations, showed an immune response with induction of IgG1, a proper balance between Th1/Th2 cytokines and reduced vertical transmission in the pups. In contrast, dams inoculated with a placebo vaccine showed clinical signs, low-scored brain lesions, augmented chronic infection with 80% positivity, 31% mortality in pups, and 81% vertical transmission. These findings indicate that rsNcGRA1 peptides in monovalent and combined with rsNCSAG4 at standard dose are potential vaccine candidates and improve the protective immune response against neosporosis in mice.

Aspirin for preeclampsia prevention in low- and middle-income countries: mind the gaps.

Preeclampsia is a syndrome that continues to be a major contributor to maternal and neonatal mortality, especially in low-income countries. Low-dose aspirin reduces the risk of preeclampsia, but the mechanism is still unknown. Risk factors to identify women at risk of preeclampsia are based on clinical characteristics. Women identified as high-risk would benefit from aspirin treatment initiated, preferably at the end of the first trimester. Current efforts have largely focused on developing screening algorithms that incorporate clinical risk factors, maternal biomarkers, and uterine artery Doppler evaluated in the first trimester. However, most studies on preeclampsia are conducted in high-income settings, raising uncertainties about whether the information gained can be totally applied in low-resource settings. In low- and middle-income countries, lack of adequate antenatal care and late commencement of antenatal care visits pose significant challenges for both screening for preeclampsia and initiating aspirin treatment. Furthermore, the preventive effect of first-trimester screening based on algorithms and subsequent aspirin treatment is primarily seen for preterm preeclampsia, and reviews indicate minimal or no impact on reducing the risk of term preeclampsia. The lack of evidence regarding the effectiveness of aspirin in preventing term preeclampsia is a crucial concern, as 75% of women will develop this subtype of the syndrome. Regarding adverse outcomes, low-dose aspirin has been linked to a possible higher risk of postpartum hemorrhage, a condition as deadly as preeclampsia in many low- and middle-income countries. The increased risk of postpartum hemorrhage among women in low-income settings should be taken into consideration when discussing which pregnant women would benefit from the use of aspirin and the ideal aspirin dosage for preventing preeclampsia. In addition, women's adherence to aspirin during pregnancy is crucial for determining its effectiveness and complications, an aspect often overlooked in trials. In this review, we analyze the knowledge gaps that must be addressed to safely increase low-dose aspirin use in low- and middle-income countries, and we propose directions for future research.

Recombinant cellobiose dehydrogenase from Thermothelomyces thermophilus: Its functional characterization and applicability in cellobionic acid production.

The fungus Thermothelomyces thermophilus is a thermotolerant microorganism that has been explored as a reservoir for enzymes (hydrolytic enzymes and oxidoreductases). The functional analysis of a recombinant cellobiose dehydrogenase (MtCDHB) from T. thermophilus demonstrated a thermophilic behavior, an optimal pH in alkaline conditions for inter-domain electron transfer, and catalytic activity on cellooligosaccharides with different degree of polymerization. Its applicability was evaluated to the sustainable production of cellobionic acid (CBA), a potential pharmaceutical and cosmetic ingredient rarely commercialized. Dissolving pulp was used as a disaccharide source for MtCDHB. Initially, recombinant exoglucanases (MtCBHI and MtCBHII) from T. thermophilus hydrolyzed the dissolving pulp, resulting in 87% cellobiose yield, which was subsequently converted into CBA by MtCDHB, achieving a 66% CBA yield after 24 h. These findings highlight the potential of MtCDHB as a novel approach to obtaining CBA through the bioconversion of a plant-based source.

Magnesium sulfate in preeclampsia: Broad indications, not only in neurological symptoms.

The role of magnesium sulfate for treatment of eclampsia is well established. The medication proved to be superior to other anticonvulsants to reduce the incidence of recurrent convulsions among women with eclampsia. Additionally, magnesium sulfate has been indicated for women with preeclampsia with different severe features. However, despite these recommendations, many clinicians are still not confident with the use of magnesium sulfate, even in settings with high incidence of preeclampsia and unacceptable rates of maternal mortality. This review brings basic science and clinical information to endorse recommendations to encourage clinicians to use magnesium sulfate for patients with all severe features of preeclampsia, not only for women with neurological symptoms. Additionally, other benefits of magnesium sulfate in anesthesia and fetal neuroprotection are also presented. Finally, a comprehensive algorithm presents recommendations to manage patients with preeclampsia with severe features between 34 and 36+6 weeks.

Functional Evaluation of Endoscopic Treatment of Ischiofemoral Impingement: Case Reports.

Ischiofemoral impingement (IFI), although infrequent, should be thought of as one of the causes of deep gluteal pain syndrome. Difficulty in establishing a diagnosis and inaccurate clinical examination can be associated with the small number of case reports in the literature. The initial IFI treatment uses conservative measures, and surgical treatment is infrequent. The following is a case report of four adult patients, all female, diagnosed with IFI, with unsuccessful conservative treatments, in whom endoscopic resection of the smaller trochanter was performed with good results.

Does Faeces Excreted by Moxidectin-Treated Sheep Impact Coprophagous Insects and the Activity of Soil Microbiota in Subtropical Pastures?

Moxidectin (MOX) is used to control helminth parasites in ruminant livestock. It is released through feces and remains in the environment for a long period. This study aimed to evaluate the impact of faeces excreted by moxidectin-treated sheep on soil biodiversity (coprophagous insects, soil microbial biomass, and activity) to establish environment-related guidelines regarding the use of MOX in sheep livestock. The study consisted of two experiments. In the first one, faeces from MOX-treated (subcutaneous dose of 0.2 mg·kg-1 body weight) and nontreated rams were placed on an animal-free pasture field, protected or not against rain, for 88 days. Then, coprophagous insects were captured, identified, and counted, and faeces degradation was evaluated by measuring dry weight and carbon (C) and nitrogen (N) contents over time. Diptera, Hymenoptera, Isoptera, and Coleoptera were equally encountered in faeces from MOX-treated and nontreated animals. Faecal boluses of MOX-treated animals (with higher N content) not protected against rain degraded faster than faecal boluses of nontreated animals (with lower N content). In the second experiment, faeces from nontreated animals were amended with increasing amounts of MOX (75 to 3,000 ng·kg-1 faeces), mixed with soil samples from animal-free pasture (1.9 to 75 ng·kg-1 soil), and incubated in a greenhouse for 28 days. Increasing concentrations of MOX did not prevent the growth of cultivable bacteria, actinobacteria, or fungi in culture media. However, even the lower MOX concentration (1.9 ng·kg-1 soil) abruptly decreased soil microbial biomass, basal respiration, and N mineralization. Thus, the results indicate that faeces excreted from sheep treated with MOX under the experimental conditions of this study are not harmful to the coprophagous insects. However, adding MOX to faeces from drug-free sheep had a negative impact on soil microbial activity and biomass.

Exposure to low-concentration fipronil impairs survival, behavior, midgut morphology and physiology of Aedes aegypti larvae.

The Aedes aegypti mosquito is a vector for various arboviruses, including dengue and yellow fever. Insecticides, such as pyrethroids and organophosphates, are widely used to manage and control these insects. However, mosquitoes have developed resistance to these chemicals. Therefore, this study aimed to investigate the effects of the commercial formulation of fipronil (Tuit® Florestal; 80% purity) on the survival, behavior, morphology, and proteins related to signaling pathways of the midgut in A. aegypti larvae under controlled laboratory conditions. Significant reductions in immature survival were observed in all concentrations of fipronil tested. Low insecticide concentration (0.5 ppb) led to decreased locomotor activity in the larvae and caused disorganization of the epithelial tissue in the midgut. Moreover, exposure to the insecticide decreased the activity of detoxifying enzymes such as catalase, superoxide dismutase, and glutathione-S-transferase. On the other hand, the insecticide increased protein oxidation and nitric oxide levels. The detection of LC3, caspase-3, and JNK proteins, related to autophagy and apoptosis, increased after exposure. However, there was a decrease in the positive cells for ERK 1/2. Furthermore, the treatment with fipronil decreased the number of positive cells for the proteins FMRF, Prospero, PH3, Wg, Armadillo, Notch, and Delta, which are related to cell proliferation and differentiation. These findings demonstrate that even at low concentrations, fipronil exerts larvicidal effects on A. aegypti by affecting behavior and enzymatic detoxification, inducing protein oxidation, free radical generation, midgut damage and cell death, and inhibiting cell proliferation and differentiation. Thus, this insecticide may represent a viable alternative for controlling the spread of this vector.

Short communication: Goat mastitis and the formation of neutrophil extracellular traps (NETs).

Mastitis, an inflammation of the mammary gland affecting milk production and quality in dairy herds, is often associated with Staphylococcus spp. in goats. Neutrophils are crucial in combating infections by migrating into milk and deploying various defense strategies, including the release of neutrophil extracellular traps (NETs) composed of DNA, histones, and bactericidal proteins. This study investigated whether NETs are released by goat neutrophils stimulated in vitro by Staphylococcus aureus and Staphylococcus warneri, two common pathogens of goat mastitis. PMNs were isolated from blood from healthy adult goats. We evaluated goat NET formation by stimulating cells with: phorbol 12-myristate 13-acetate (PMA) as a positive control, cytochalasin for inhibition of actin polymerization, S. aureus, and S. warneri. NET formation was observed in response to chemical stimulation and bacterial presence, effectively trapping pathogens. Variations in NET formation between S. aureus and S. warneri suggest pathogen-specific responses. These findings suggest that the formation of NETs may be an important complementary mechanism in the defense against mastitis in goats. In conclusion, this study unveils a novel defense mechanism in goats, indicating the role of NETs against S. aureus and S. warneri in mastitis.

Exposure to the herbicide tebuthiuron affects behavior, enzymatic activity, morphology and physiology of the midgut of the stingless bee Partamona helleri.

Partamona helleri is an important pollinator in the Neotropics. However, this bee faces an increased risk of pesticide exposure, potentially affecting both individual bees and entire colonies. Thus, this study aimed to evaluate the effects of the herbicide tebuthiuron on behavior, antioxidant activity, midgut morphology, and signaling pathways related to cell death, cell proliferation and differentiation in P. helleri workers. tebuthiuron significantly reduced locomotor activity and induced morphological changes in the midgut. The activity of the detoxification enzymes superoxide dismutase and glutathione S-transferase increased after exposure, indicating a detoxification mechanism. Furthermore, the herbicide led to alterations in the number of positive cells for signaling-pathway proteins in the midgut of bees, suggesting induction of apoptotic cell death and disruption of midgut epithelial regeneration. Therefore, tebuthiuron may negatively impact the behavior, antioxidant activity, morphology, and physiology of P. helleri workers, potentially posing a threat to the survival of this non-target organism.