Polyethylene microplastics and substrate availability can affect emergence responses of the freshwater insect Chironomus sancticaroli.

Pollution caused by polyethylene microplastics (MP) has been reported for aquatic environments worldwide. However, despite recurrent research for several aquatic organisms, the effects of MP on the emergence stage of freshwater insects from tropical environments are little known. This study is the first to assess the emergence of the Brazilian native species Chironomus sancticaroli Strixino & Strixino, 1981 when exposed to primary polyethylene microplastics (size 40-48 µm). We performed two exposure scenarios, with a substrate (standard assays) and without substrate (as a stressful experience), and recorded emergence responses. The MP did not affect the species' emergence rate, but these rates were statistically different for the standard and stressful exposure scenarios. In bioassays without substrate, the high concentrations of MP caused anticipation of the insect's emergence (5-6 days). On the other hand, female emergence time was longer than males in standard bioassays. The substrate absence caused a slight increase in the left female wing's length and the potential female fecundity. These findings suggest that the polyethylene microplastics and substrate availability can affect the emergence dynamics of the tropical insect C. sancticaroli.

Global occurrence of SARS-CoV-2 in environmental aquatic matrices and its implications for sanitation and vulnerabilities in Brazil and developing countries.

This paper includes a systematic review of the SARS-CoV-2 occurrence in environmental aquatic matrices and a critical sanitation analysis. We discussed the interconnection of sanitation services (wastewater, water supply, solid waste, and stormwater drainage) functioning as an important network for controlling the spread of SARS-CoV-2 in waters. We collected 98 studies containing data of the SARS-CoV-2 occurrence in aquatic matrices around the world, of which 40% were from developing countries. Alongside a significant number of people infected by the virus, developing countries face socioeconomic deficiencies and insufficient public investment in infrastructure. Therefore, our study focused on highlighting solutions to provide sanitation in developing countries, considering the virus control in waters by disinfection techniques and sanitary measures, including alternatives for the vulnerable communities. The need for multilateral efforts to improve the universal coverage of sanitation services demands urgent attention in a pandemic scenario.

A systematic review of the water treatment sludge toxicity to terrestrial and aquatic biota: state of the art and management challenges.

Safe drinking water' supply is an essential service and depends directly on the water treatment that produces water treatment sludge (WTS) as a product, whose final destination varies and remains a challenge. The ecotoxicity assessment of the WTS address the ecological implications of the WTS disposal but these information is still scarce in the literature. In this sense, we did a systematic review of the ecotoxicological studies on WTS using databases from six platforms. From the 785 papers recovered; 16 studies were eligible and showed the ecotoxicity assays' applicability to evaluate the WTS. We discussed WTS ecotoxicity considering sample characterization; terrestrial and aquatic toxicity assays; and WTS challenges. WTS proved to be a highly heterogeneous matrix composed mainly of coagulant precipitates, including Al and Fe. Studies lack consensus concerning the most representative/sensitive species for evaluating WTS' toxicity. Crustaceans were the most studied aquatic group, although algae species were more sensitive. Besides, soil ecotoxicity assessed only plant growth, and a single study used the earthworm. Even papers used bioassays to indicate the recycling WTS' feasibility, there is a lack of specific legislation regarding the WTS reuse. Furthermore, are necessary a regulation for WTS management that involves an ecological risk assessment.

A novel approach for an immunogen against Corynebacterium pseudotuberculosis infection: An Escherichia coli bacterin expressing phospholipase D.

Corynebacterium pseudotuberculosis is the causative agent of caseous lymphadenitis (CLA) in small ruminants. There is still needed an immunoprophylaxis model, which induces a protective and sustained immune response against the bacteria. In this study, we evaluated a recombinant Escherichia coli bacterin expressing the recombinant phospholipase D (rPLD) protein, the most relevant virulence factor of C. pseudotuberculosis, as a potential vaccine formulation. E. coli BL21 (DE3) Star strain was used for rPLD protein expression and was then inactivated by formaldehyde. Four groups with 10 Balb/c mice each were immunized twice within a 21 days interval: G1-control - 0.9% saline solution; G2- E. coli bacterin/pAE (naked plasmid); G3- E. coli bacterin/pAE/pld; G4-purified recombinant rPLD. Subsequently, the animals were challenged with a C. pseudotuberculosis virulent strain and evaluated for 40 days. The highest survival rate was observed for G3 with 40% protection, followed by 30% in the purified rPLD group (G4). These two groups also showed considerable IgG production when compared with the control group (G1). Also, a higher significant expression of interferon-γ was observed for the experimental groups G2, G3, and G4 when compared with a control group (G1) (p < 0.05). These results represent that a recombinant bacterin can be seen as a promising approach for vaccinal antigens against CLA, being possible to be used in association of different vaccine strategies.

Vaccines for caseous lymphadenitis: up-to-date and forward-looking strategies.

Caseous lymphadenitis (CLA) is an infectious chronic disease responsible for economic losses in sheep and goat breeding worldwide. CLA has no effective treatment, evidencing the vaccination schedule as the best control strategy. Although some commercial vaccines have been available, none of them provides total protection, which is sometimes insufficient and does not reach the same efficiency when compared in sheep and goats. They also have questionable safety levels and side effects. In light of this, several experimental vaccines are in development in order to improve safety, reproducibility, and protective immune response against the etiologic agent of CLA, Corynebacterium pseudotuberculosis. In this review, we discussed aspects as antigen, adjuvant, routes of administration, protection level, and animal models used in CLA vaccine development, as well the challenges and future perspectives. KEY POINTS: Caseous lymphadenitis (CLA) does not have an appropriate commercial vaccine. Different experimental vaccines are in development aiming to protect against Corynebacterium pseudotuberculosis. An ideal vaccine for CLA is necessary for the disease control.

In silico analyses and design of a chimeric protein containing epitopes of SpaC, PknG, NanH, and SodC proteins for the control of caseous lymphadenitis.

Caseous lymphadenitis (CLA) is an infectious disease that affects goats and sheep causing drastic impacts on milk and meat production and is caused by Corynebacterium pseudotuberculosis. The disease can be prevented through vaccination but currently, vaccines demonstrate limited efficacy consequently leading to a need for the development of new ones. Here, we described the in silico development of a new chimeric protein constructed with epitopes identified from the sequences of the genes nanH, pknG, spaC, and sodC, previously described as potential vaccinal targets against C. pseudotuberculosis. The chimera was expressed, purified, and its immunogenicity was evaluated using sera of immunized mice. Results indicate the chimeric protein was able to stimulate antibody production. Additionally, analysis using serum from naturally infected goats showed that the protein is recognized by sera from these animals, indicating the possibility for using this chimera in new diagnostic methods. KEY POINTS: • The chimera was expressed with 52 kDa and a yield of 7 mg/L after purification. • The chimera was recognized by the sera of animals immunized with this formulation. • Chimera reacted with the serum of goats naturally infected with C. pseudotuberculosis.

The combination of Brazilian red propolis and recombinant protein rCP01850 in the immunoprophylaxis of Corynebacterium pseudotuberculosis infection in mice.

The immunomodulatory properties of Brazilian red propolis (BRP) have been already described. Also, propolis have been proved to have antibacterial activity on Corynebacterium pseudotuberculosis. An adjuvant effect of red propolis oil was able to induce a significant anti-C. pseudotuberculosis humoral immune response. Here, we demonstrate for the first time the immunostimulant property of BRP hydroalcoholic extract (BRPHE) in a recombinant vaccine against caseous lymphadenitis. Mice BALB/c were allocated in three groups inoculated with: sterile saline solution (G1); BRPHE (G2); or BRPHE combined with the C. pseudotuberculosis rCP01850 recombinant protein (G3) in two doses within a 21-days-interval. Blood samples were collected for the total IgG, IgG1 and IgG2a measurement. Mice were challenged with a virulent C. pseudotuberculosis strain, and other 6 mice were used for IFN-γ and IL-10 levels determination after splenocyte stimulation with the recombinant antigen. G3 showed higher significant levels of antibodies on the 42nd experimental day, with a high IgG2a/IgG1 proportion. G2 and G3 presented significant production of IFN-γ and IL-10, while G3 presented the higher levels of IFN-γ (p < 0.05). After challenge, G2 showed a survival rate of 20%, while 70% of mice from G3 survived the experimental challenge. In conclusion, BRPHE used alone has immunostimulant properties specially on cellular immune response, and when used in combination with the recombinant protein rCP01850 induces cellular and humoral immune responses as well as a significant survival of inoculated mice.

Administration of Lactobacillus plantarum Lp62 to dam rats at the end of delivery and during lactation affects TGF-ß1 level and nutritional milk composition, and body weight of pups.

PURPOSE: Lactobacillus plantarum Lp62 is a lactic acid bacteria strain that has been isolated from cocoa beans and exhibited probiotic potential. The influence of oral administration of L. plantarum Lp62 on the growth of rat's pups; on yield, cytokines and milk composition was studied. METHODS: Lactobacillus plantarum Lp62 is a lactic acid bacteria strain that has been isolated from cocoa beans. It was administered daily by gavage to Wistar rats (n = 8), from the 7th day before delivery and for 20 days during lactation, in a concentration of 1.44 × 109 CFU/rat. The dam and pups were weighed and milk was collected at 12th and 19th day for determination of protein, triglycerides, cholesterol and lactose by colorimetric assays. TGF-ß1 milk levels were analyzed by ELISA. The mammary glands of rats were removed for histological analysis. To detect statistical differences between the groups, tests of mean differences at a significance level of 5% was performed. RESULTS: Supplementation with L. plantarum L62 resulted in significant higher weight of pups (p < 0.05), with similar weight on dams (p > 0.05). The milk yield was not altered by L. plantarum treatment, but the levels of protein, triglycerides and cholesterol were increased (p < 0.05), with no difference in lactose concentration (p > 0.05). Levels of TGF-ß1 were higher in the milk of L. plantarum treatment (p < 0.05). CONCLUSIONS: The treatment of dams at the end of pregnancy and lactation with L. plantarum Lp62 increased nutritional content of milk, probably contributing to the higher weight of the pups. The higher levels of TGF-ß1 in the milk, could promote immune benefits to the pups. Further studies in this field are needed to prove the potential use of L. plantarum Lp62 as a probiotic.

Essential oil from Brazilian Red Propolis exhibits anthelmintic activity against larvae of Toxocara cati.

Toxocara spp. are responsible for causing toxocariasis, a zoonotic disease of global importance, which is difficult to treat as the available drugs have moderate efficacy in the clinical resolution of the disease. A promising alternative to the existing drugs is Propolis, which is known for having biological and pharmacological properties such as antiparasitic, antioxidant, and antitumor activities. In this study, we report the in vitro anthelmintic activity of essential oil from Brazilian Red Propolis (EOP) against larvae of Toxocara cati. Approximately 100 larvae per well were cultivated in microplates containing RPMI-1640 medium and incubated in the presence of EOP (18.75, 37.5, 75, 150, 300 and 600 µg/mL) to determine the Minimum Inhibitory Concentration (MIC) and IC50 (concentration required to inhibit 50% of the population) values. Then, T. cati larvae treated with the MIC of EOP were inoculated in mice to evaluate their progression in vivo. A concentration of 600 µg/mL of EOP showed 100% larvicidal activity after exposure for 48 h, while 300 µg/mL represented the IC50 and CC50. The anthelmintic activity of EOP was confirmed by the inability of the treated T. cati larvae to infect the mice. Our findings demonstrate the potential of EOP as an anthelmintic.

Chironomus sancticaroli (Diptera, Chironomidae) as a Sensitive Test Species: Can We Rely on Its Use After Repeated Generations, Under Laboratory Conditions?

In ecotoxicological assays, previously selected and standardized organism tests are exposed to an environmental sample. Some species of the Chironomus genus have been extensively used in ecotoxicological assays. Among these, Chironomus tentans is usually utilized in the USA and Chironomus sancticaroli in Brazil. We conducted ecotoxicological bioassays to compare a population of C. sancticaroli, kept for 6 years under laboratory conditions, with a sylvatic population of the same species, collected in the field. The aim was to test the hypothesis that populations of C. sancticaroli, maintained in the laboratory for long periods, could have a different response to stressors/substances. We analyzed the responses of C. sancticaroli for potassium chloride, zinc chloride, potassium dichromate, linear alkylbenzene sulphonate (LAS) and caffeine. The results showed no significant differences between the two populations in the analyses and seems to indicate the possible use of C. sancticaroli from populations kept in the laboratory for long periods.

Microbial Characterization of Methanogenic and Iron-reducing Consortium in Reactors with Polychlorinated Biphenyls.

Recent papers have confirmed current environmental pollution and the continuous release of polychlorinated biphenyls (PCBs) despite the prohibition of its manufacture worldwide. As the dehalogenating microorganisms are able to remove halogens from various analogous compounds, the characterization of PCB metabolisms can improve the degradation of similar compounds. Thus, this study extensively evaluated the microbial community developed in methanogenic and iron-reducing reactors. The horizontal-flow anaerobic reactor (HAIB) with real waste of Aroclor (1 mL L-1) was fed with mineral medium, ethanol, and sodium formate. Bacteria belonging to Thermotogaceae (Thermotogae), Geobacteraceae, Chloroflexi, Proteobacteria, and Firmicutes (Clostridium) were identified in the HAIB reactor. Bacteria belonging to the Chloroflexi, Firmicutes, and Geobacteraceae are associated with the degradation of hydrocarbons and could be related to the Aroclor waste in this paper. Furthermore, 5.26 × 1012 cells gTVS-1 of iron-reducing bacteria were quantified by the most probable number method in the HAIB reactor, suggesting that this group has an important role in aromatic degradation. Moreover, the evaluation of methanogenic and iron-reducing microorganisms in batch reactors with Aroclor 1260 was performed and the biomass growth was not affected by the addition of PCB. The methane production reached 0.38 µmol CH4 gTVS-1 and the iron reduction attained 90% in batch reactors. Through microbial analyses from HAIB and batch reactors, lower diversity was evidenced in the presence of PCB. This paper indicates the relevant role of iron-reducing organisms and Chloroflexi, Geobacteraceae, and Firmicutes group in PCB metabolism.

New cholinesterase inhibitors for Alzheimer's disease: Structure Activity Studies (SARs) and molecular docking of isoquinolone and azepanone derivatives.

A library of isoquinolinone and azepanone derivatives were screened for both acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activity. The strategy adopted included (a) in vitro biological assays, against eel AChE (EeAChE) and equine serum BuChE (EqBuChE) in order to determine the compounds IC50 and their dose-response activity, consolidated by (b) molecular docking studies to evaluate the docking poses and interatomic interactions in the case of the hit compounds, validated by STD-NMR studies. Compound (1f) was identified as one of these hits with an IC50 of 89.5µM for EeAChE and 153.8µM for EqBuChE, (2a) was identified as a second hit with an IC50 of 108.4µM (EeAChE) and 277.8µM (EqBuChE). In order to gain insights into the binding mode and principle active site interactions of these molecules, (R)-(1f) along with 3 other analogues (also as the R-enantiomer) were docked into both RhAChE and hBuChE models. Galantamine was used as the benchmark. The docking study was validated by performing an STD-NMR study of (1f) with EeAChE using galantamine as the benchmark.

[Poor metabolic control in primary care]. / Causas de descontrol metabólico en atención primaria.

INTRODUCTION: Poor metabolic control is a constant in patients with diabetes worldwide, despite resources demonstrated to achieve therapeutic targets. The object of this study was to identify causes of poor metabolic control in patients with diabetes treated in Family Medicine Clinics in metropolitan Mexico City at the Instituto Mexicano del Seguro Social. MATERIAL AND METHODS: We analyzed 638 of 1,170 patients studied between 2000 and 2006. Anthropometric variables, occurrence of infections, treatment adherence, medical prescriptions, diet, exercise, and laboratory results were recorded. RESULTS: The proportion of patients with HbA1c < 7% worsened over time: from 38.9% at baseline it decreased to 21.4% (p < 0.001); LDL cholesterol decreased from 51.9 to 12.2% (p < 0.001), and controlled blood pressure from 35.6 to 23.3% (p < 0.001). A diet high in calories was associated with poor metabolic control (OR: 2.36; 95% CI: 1.34-4.13) and treatment intensification with elevated HbA1c (OR: 2.1; 95% CI: 1.14-4.14). Treatment was not intensified in 90% of patients outside targets. Infections, non-adherence, and drugs that interfere with oral hypoglycemic agents were not associated with higher HbA1c. CONCLUSIONS: The main factors associated with higher HbA1c were: disease progression, an inadequate diet, and lack of treatment intensification. Any program designed to improve the conditions of these patients must consider these factors.

Professionals and interfamily violence against children and adolescents: in between legal and conceptual precepts.

OBJECTIVE: To identify the conceptions of professionals regarding interfamily violence against children and adolescents. METHOD: A qualitative study conducted with 15 professionals who had taken children and adolescents under their care as a result of interfamily violence. Data were collected between November, 2013, and March, 2015, through semi-structured interviews. Data were organized and analyzed using the Textual Discourse Analysis technique. RESULTS: The professional discourse highlighted that some legal aspects regarding the handling of interfamily violence against children and adolescents are neglected; an omission supported by the justification of professionals to preserve the family. We highlight the confrontation between the concept of family as a caregiver and the family that commits violence against children, in addition to the positioning of professionals, which does not include the family or the aggressor in the intervention process in facing situations of interfamily violence attended to by the services. CONCLUSION: Acting against interfamily violence requires professionals to do away with some pre-established concepts in ordee to put the actual needs of victims and families into evidence. OBJETIVO: Identificar, com base no discurso dos profissionais, suas concepções a respeito da violência intrafamiliar contra crianças e adolescentes. MÉTODO: Estudo qualitativo, realizado com 15 profissionais, que tiveram sob seus cuidados crianças e adolescentes atendidas em decorrência da violência intrafamiliar. Os dados foram coletados entre novembro de 2013 e março de 2015, por meio de entrevistas semiestruturadas. Os dados foram organizados e analisados utilizando a técnica de Análise Textual Discursiva. RESULTADOS: O discurso dos profissionais colocou em evidência que alguns aspectos legais em relação ao manejo da violência intrafamiliar contra crianças e adolescentes são negligenciados, omissão respaldada pela justificativa dos profissionais de preservar a família. Destaca-se o confronto entre a concepção de família como cuidadora e a família que violenta os filhos, além do posicionamento dos profissionais, os quais não incluem a família e o agressor nos processos de intervenção frente às situações de violência intrafamiliar atendidas nos serviços. CONCLUSÃO: Atuar frente à violência intrafamiliar requer do profissional romper com algumas concepções preestabelecidas para colocar em evidência as reais necessidades de vítimas e famílias.

Quality of granola prepared with dried caju-do-cerrado (Anacardium othonianum Rizz) and baru almonds (Dipteryx alata Vog).

The use of Brazilian Cerrado fruits and research into their nutritional potential are important for socioeconomic development and the sustainable preservation of the environment. The use of these fruits in products such as granola encourages the inclusion of healthier and more-natural foods in the diet. This study was undertaken to evaluate acceptability, microbiological, physical and nutritional characteristics and the stability of granola made from dried caju-do-cerrado and baru almonds. Granola containing Cerrado fruits had high levels of protein content (117.4 g/kg), dietary fiber (115.3 g/kg) and iron (32.1 mg/kg) and had lower moisture (57.0 g/kg), water activity (0.3), sodium (577.7 mg/kg), lipids (150.2 g/kg) and energy value (3952.2 kcal/kg) than did the control. After storage for 100 days, the granola presented adequate microbiological conditions, with acceptability scores higher than 7 assigned by 85.5 % to 95.2 % of the judges and a crunchy texture. The high nutritional potential of granola containing Cerrado fruits, coupled with its stability over 100 days of storage, may contribute to the appreciation and consumption of these fruits and meet the growing demand for healthier, more natural foods.

[Perception of fathers as for their involvement in activities with their children]. / A percepção dos pais frente ao seu envolvimento nas atividades com o(s) filho(s).

This is an exploratory, descriptive study with a quantitative approach and the aim to identzfy the perception of fathers regarding their children's needs; strategies used by fathers to get closer to their children as well as to analyze the influence of household chores and children's education in their fathers' lives. Study subjects were 92 men with six-year-old children, residing in the city of Rio Grande, state of Rio Grande do Sul (RS). The results revealed fathers who are more engaged in activities with their children, valuing confidence, safety, as well as proximity to family as children's main needs, having prioritized the progress children make as well as attention to listening and conversation. Children's education does not aggregate more problems than they imagined, managing to plan life the way they seek to. These findings show that, in the sample studied, fathers have been able to develop more affectionate actions aimed at being more involved with their children.

Effect of IL-10 and TNF-α on the competence and cryosurvival of in vitro produced Bos indicus embryos.

In vitro-produced embryos are constantly exposed to stressful conditions that can lead to the activation of the apoptotic pathway. The nuclear Kappa B factor (NF-κB) is an inflammatory mediator that induces the expression of tumor necrosis factor (TNF-α), a pro-inflammatory cytokine, while interleukin-10 (IL-10), an anti-inflammatory cytokine, inhibits NF-κB activity. This study aimed to investigate the effects of IL-10 and TNF-α on the competence and cryosurvival of in vitro-produced bovine embryos. Embryos were produced in vitro using standard protocols, and Grade I blastocysts were vitrified using the Cryotop method. Non-vitrified and vitrified blastocysts were subjected to the TUNEL assay. In Experiment I, on day 6.5 (156 h post-insemination), the embryos were treated with PBS (control), 50 ng/mL of IL-10, or a combination of 25 ng/mL of TNF-α and 50 ng/mL of IL-10. Embryonic development and apoptotic rates were monitored. In Experiment II, the same groups were set up, with the addition of a group treated with 25 ng/mL of TNF-α alone. Grade I blastocysts were vitrified 5 h after treatment, and cryosurvival was monitored at until 48 h post-warming. The apoptosis rate and total cell number were investigated in the vitrified-hatched blastocysts. IL-10 alone did not affect developmental competence or cryosurvival (P > 0.05). The IL-10-treated embryos, when exposed in combination with TNF-α, presented a detrimental effect (P < 0.05) in the embryonic development of non-vitrified embryos. However, vitrified blastocysts had no negative effect (P > 0.05). The TNF-α treatment reduced (P < 0.05) the re-expansion rate at 6 h post-warming and increased (P < 0.05) the apoptosis rate in vitrified hatched blastocysts, whereas no effect (P > 0.05) of the treatments was detected in the hatching rate and total cell number post-warming. In conclusion, TNF-α has a detrimental effect on embryonic developmental competence and cryosurvival by compromising the development of non-vitrified embryos and apoptotic-related events of vitrified blastocysts, whereas IL-10, when in combination with TNF-α, appears to attenuate the detrimental effects of TNF-α.

Risk Perception and Fatigue in Port Workers: A Pilot Study.

INTRODUCTION AND OBJECTIVES: The aims of this study were to assess fatigue in port workers; analyze the association between fatigue and levels of trust in organizations, as well as the association between authorities and risk perception; and examine the official documents governing the studied port, along with the current health and communication status of the port workers. MATERIALS AND METHODS: This was a descriptive and cross-sectional pilot study, which presented quantitative and qualitative data, and it was carried out among port workers in the city of Pelotas, Rio Grande do Sul, Brazil. Thirty-nine port workers responded to quantitative questionnaires, which collected their socio-demographic data, as well as a risk perception questionnaire, the Chalder Fatigue Scale, and the Checklist of Individual Strength. Five documents from the port regiment were studied and qualitatively analyzed. The health communications consisted of presenting infographics with research data and providing information for reducing fatigue. RESULTS: Fifteen workers (38.5%) were considered fatigued. There was a reduction in fatigue associated with trust in the unions and the labor management body, and there was an agreement that the precarious environment was completely unacceptable. The qualitative data in the documents indicated that it was possible to identify the infrastructure of the port environment, the legislation, the strategies to be adopted in cases of natural disasters, emergency plans, plans for the protection and promotion of workers' health, individual and collective protection plans, the division of the sectors and those responsible for them, and documents detailing the hierarchy within the ports. The qualitative analysis culminated in graphic representations (infographics) created to communicate the research results to port workers, specifically in relation to fatigue, and we presented the ways to prevent fatigue at work. Discussion/Limitations: Studying the risk perceptions and fatigue levels of port workers through research with the active participation of these workers presented their lived experiences, which promoted discussion and perhaps more effective proposals to change their work conditions.

Unraveling the Consequences of Oxygen Imbalance on Early Embryo Development: Exploring Mitigation Strategies.

Although well-established and adopted by commercial laboratories, the in vitro embryo production system still requires refinements to achieve its highest efficiency. Early embryonic development is a dynamic event, demanding suitable conditions to provide a high number of embryos with quality and competence. The first step to obtaining an optimized in vitro environment is to know the embryonic metabolism and energy request throughout the different stages of development. Oxygen plays a crucial role in several key biological processes necessary to sustain and complete embryonic development. Nonetheless, there is still controversy regarding the optimal in vitro atmospheric concentrations during culture. Herein, we discuss the impact of oxygen tension on the viability of in vitro-produced embryos during early development. The importance of oxygen tension is addressed as its roles regarding essential embryonic traits, including embryo production rates, embryonic cell viability, gene expression profile, epigenetic regulation, and post-cryopreservation survival. Finally, we highlight the damage caused by in vitro unbalanced oxygen tensions and strategies to mitigate the harmful effects.

Species-specific molecular differentiation of embryonic inner cell mass and trophectoderm: A systematic review.

A wide-ranging review study regarding the molecular characterization of the first cell lineages of the developmental embryo is lacking, especially for the primary events during earliest differentiation which leads to the determination of cellular fate. Here, a systematic review and meta-analysis were conducted according to PRISMA guidelines. MEDLINE-PubMed was searched based on an established search strategy through April 2021. Thirty-six studies fulfilling the inclusion criteria were subjected to qualitative and quantitative analysis. Among the studies, 50 % (18/36) used mice as an animal model, 22.2 % (8/36) pigs, 16.7 % (6/36) cattle, 5.5 % (2/36) humans, and 2.8 % (1/36) goats as well as 2.8 % (1/36) equine. Our results demonstrated that each of the first cell lineages of embryos requires a certain pattern of expression to establish the cellular determination of fate. Moreover, these patterns are shared by many species, particularly for those molecules that have already been identified in the literature as biomarkers. In conclusion, the present study integrated carefully chosen studies regarding embryonic development and first cellular decisions in mammalian species and summarized the information about the differential characterization of the first cell lineages and their possible relationship with specific gene expression.