Immunolocalization of melatonin receptors in bovine ovarian follicles and in vitro effects of melatonin on growth, viability and gene expression in secondary follicles

This study aims to investigate the (1) expression of melatonin receptors types 1A/B (MTNR1A/B) in bovine ovaries and (2) the in vitro effects of melatonin on secondary follicle development, antrum formation, viability, and expression of messenger ribonucleic acid (mRNA) for superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase-1 (GPX1) and peroxiredoxin 6 (PRDX6). The expression of MTNR1A/B in bovine ovarian follicles was demonstrated by immunohistochemistry. To choose the most effective concentration of melatonin on follicular growth and viability, isolated secondary follicles were cultured individually at 38.5°C, with 5% CO₂ in air, for 18 d in TCM-199⁺ alone or supplemented with 10^-11, 10^-9, 10^-7 or 10^-5 M melatonin. Then, melatonin receptor antagonist, luzindole, was tested to further evaluate the mechanisms of actions of melatonin, that is, the follicles were cultured in control medium alone or supplemented with 10^-7 M melatonin, 10 µM luzindole and both 10^-7 M melatonin and 10 µM luzindole. Follicular growth, morphology and antrum formation were evaluated at days 6, 12 and 18. At the end of culture, viability of secondary follicles was analyzed by calcein-AM and ethidium homodimer-1, and the relative levels of mRNA for SOD, CAT, GPX1 and PRDX6 were evaluated by real time polymerase chain reaction. Immunohistochemistry results showed expression of MTNR1A/B in oocyte and granulosa cells of primordial, primary, secondary and antral follicles. Secondary follicles cultured in medium supplemented with melatonin at different concentrations had well preserved follicles after 18 d of culture. Furthermore, follicles cultured in presence of 10^-7 M melatonin presented significantly higher diameters than those cultured in other treatments. The presence of melatonin receptor antagonist, luzindole, blocked the effects of melatonin on follicular growth and viability. In addition, follicles cultured in medium containing only melatonin had significantly higher rates of antrum formation. Follicles cultured in medium containing only melatonin had higher relative levels of mRNA for CAT, SOD and PRDX-6 than those cultured with both melatonin and luzindole. Follicles cultured with luzindole only or both melatonin and luzindole had lower relative levels of mRNA for PRDX6 and GPX1 than those cultured control medium. In conclusion, melatonin promotes growth of bovine secondary follicles through its membrane-coupled receptors, while luzindole blocks the effects of melatonin on follicle growth and reduces the expression of antioxidant enzymes in cultured follicles.

Growth and hematological responses of tambaqui, Colossoma macropomum fed different levels of rice, Oryza spp

The tambaqui (Colossoma macropomum) is a fish of primary importance in South American aquaculture, principally in the Amazon region and has a particularly unique diet in the wild. Oryza spp, or Wild rice as it is commonly known, is native to the floodplains of muddy rivers in the Amazon region. The aim of this study was to analyze the physical performance and the effects of dietary levels of Oryza spp. via the hematological parameters, total food intake, conversion efficiency, growth ratio and swimming performance of this fish. Diets containing 45% Oryza spp. induced the best performance in tambaqui. Diets containing 15% and 30% did not affect these indices, thus indicating that this amount of Oryza can be used as an alternative energy source for this important species within Brazilian aquaculture.

Antibacterial effects of the lectin from pomegranate sarcotesta (PgTeL) against Listeria monocytogenes

AIMS

To investigate the effects of the lectin from Punica granatum sarcotesta (PgTeL) on growth, viability, cell structure, biofilm formation and chitinase activity of Listeria monocytogenes. In addition, the effect of PgTeL on the adhesion and invasion of human cells (HeLa) was determined.

METHODS AND RESULTS

PgTeL showed bacteriostatic and bactericidal effects on the strains L. monocytogenes N53-1 and EGD-e, causing morphometric alterations, cell aggregation, strong deformation and cell disruption. PgTeL inhibited biofilm formation by EGD-e and N53-1 and also interfered with the adhesion and invasion processes of EGD-e and N53-1 in HeLa cells. Finally, the chitinase activity of L. monocytogenes EGD-e was reduced in the presence of PgTeL, which can be involved in the inhibition of adhesion process.

CONCLUSION

PgTeL is an antibacterial agent against L. monocytogenes, inhibiting growth and promoting cell death, as well as impairing biofilm formation and bacterial adhesion and invasion into human cells.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results stimulate future investigations on the potential of PgTeL for protection of contamination in food products.

Effects of epidermal growth factor and progesterone on development, ultrastructure and gene expression of bovine secondary follicles cultured in vitro

The aims of this study were to investigate the effects of epidermal growth factor (EGF) and progesterone on the development, viability and the gene expression of bovine secondary follicle culture in vitro for 18 days. Secondary follicles (∼0.2 mm) were isolated from ovarian cortex and individually cultured at 38.5 °C, with 5% CO₂ in air, for 18 days, in TCM-199⁺ (n = 63) alone (control medium) or supplemented with 10 ng/mL progesterone (n = 64), 10 ng/mL EGF (n = 61) or both EGF and progesterone (n = 66). The effects of these treatments on growth, antrum formation, viability, ultrastructure and mRNA levels for GDF-9, c-MOS, H1foo and cyclin B1 were evaluated, significantly different (p < 0.05). The results showed that there was a progressive increase in follicular diameter in all treatments, but only follicles cultured in medium supplemented with EGF had increased significantly in diameter when compared to follicles cultured in the control medium at the end of the culture period, significantly different (p < 0.05). A positive interaction between EGF and progesterone was not observed. In addition, the presence of EGF, progesterone or both in culture medium did not influence the rate of follicle survival and antrum formation. However, the presence of only progesterone in cultured medium increased the expression of mRNAs for GDF9 and cyclin B1 in oocytes. EGF also significantly increased the levels of mRNAs for cMOS and GDF9 when compared to follicles cultured in control medium. Ultrastructural analyzes showed that cultured follicles in all treatments maintained the integrity of granulosa cells. In conclusion, the EGF promotes the development of secondary follicles cultured in vitro for 18 days and increases the expression of cMOS and GDF9, while progesterone alone or in association with EGF have not a positive effect on follicular growth. However, progesterone increases the expression of GDF9 and cyclin B1 in oocytes.

α-Linolenic acid prevents hepatic steatosis and improves glucose tolerance in mice fed a high-fat diet

OBJECTIVES

Dietary omega-3 fatty acids have been efficacious in decreasing serum cholesterol levels and reducing the risk of cardiovascular disease. However, the metabolic and molecular changes induced by the omega-3 fatty acid α-linolenic acid (ALA), which is found in linseed oil, are not fully understood. In this study, we showed a correlation between ALA and insulin resistance, inflammation and endoplasmic reticulum stress (ERS).

METHODS

We studied 40 male mice (C57/BL6) divided into 4 groups: a control (C) group, a control + omega-3/ALA (CA) group, a high-fat diet (HFD) (H) group and a high-fat diet + omega-3/ALA (HA) group. For 8 weeks, the animals in the H and HA groups were fed a high-fat (60%) diet, while the animals in the C and CA groups received regular chow. The diets of the CA and HA groups were supplemented with 10% lyophilized ALA.

RESULTS

ALA supplementation improved glucose tolerance and reduced insulin resistance, as measured by intraperitoneal glucose tolerance tests and the homeostasis model assessment for insulin resistance, respectively. In addition, ALA reduced hepatic steatosis and modified the standard fat concentration in the liver of animals fed an HFD. Dietary ALA supplementation reduced the serum levels of interleukin 6 (IL-6), interleukin 1 beta (IL-1β) and monocyte chemoattractant protein-1 (MCP-1), increased the expression of important chaperones such as binding immunoglobulin protein (BIP) and heat shock protein 70 (HSP70) and reduced the expression of C/EBP-homologous protein (CHOP) and X-box binding protein 1 (XBP1) in hepatic tissues, suggesting an ERS adaptation in response to ALA supplementation.

CONCLUSIONS

Dietary ALA supplementation is effective in preventing hepatic steatosis; is associated with a reduction in insulin resistance, inflammation and ERS; and represents an alternative for improving liver function and obtaining metabolic benefits.

Effects of frutalin and doxorubicin on growth, ultrastructure and gene expression in goat secondary follicles cultured in vitro

This study evaluated the effects of frutalin (0.6, 6.0 or 60.0 μg/mL) and doxorubicin (0.3 μg/mL) on survival, growth and ultrastructure of in-vitro cultured goat secondary follicles. The effects of these substances on the levels of mRNA for Casp3, Casp6, Bax, and Bcl2 were also investigated. Results showed that, after 6 days of culture, frutalin or doxorubicin reduced the percentage of normal follicles (P < 0.05), but doxorubicin had higher toxicity than frutalin. Except for follicles cultured with 0.6 μg/mL frutalin, follicular growth rate was reduced after culture with doxorubicin or frutalin (P < 0.05). The presence doxorubicin or 60.0 μg/mL frutalin increased the levels of mRNA for Casp3, Casp6, Bax, and Bcl2 (P < 0.05). Higher mRNA levels for Casp3, Casp6 and Bax were found in follicles cultured with doxorubicin, but higher levels of Bcl2 mRNA were found in follicles cultured with frutalin (P < 0.05). In conclusion, frutalin has lower toxic effects than doxorubicin on secondary follicles cultured in vitro.

Comparing the Ability of Anthropometric Indicators in Identifying Metabolic Syndrome in HIV Patients

BACKGROUND

Highly active antiretroviral therapy (HAART) can cause side effects in HIV patients, as the metabolic syndrome. Early identification of risk for development of cardiovascular diseases using available reliable and practical methods is fundamental. On this basis, the aim of this study was to compare the effectiveness of anthropometric indicators to identify metabolic syndrome in HIV patients on HAART.

METHODS

It is a cross-sectional study. A number of 280 stable HIV patients were studied. It measured weight, height, waist circumference (WC), hip circumference (HP), thigh circumference (TC) and calculated body mass index (BMI), body adiposity index (BAI), waist to hip ratio (WHR) and waist to thigh ratio (WTR). There was also a performance of biochemical tests of lipid profile and fasting glucose. Systemic blood pressure was measured. The criteria proposed by the National Cholesterol Education Program III (NCEP-ATP III) to metabolic syndrome classification was used. Individuals were divided in groups with or without metabolic alterations and their anthropometric indicators were compared. Receiver operating characteristic (ROC) curves were designed for each anthropometric indicator using the metabolic syndrome classification to identify sensitivity and specificity.

RESULTS

WC was a good tool to identify each metabolic disorder separately: total cholesterol (only females, p<0.05), triglycerides (only males, p<0.001), HDL cholesterol (p<0.05), LDL cholesterol (p<005) and fasting glycemic (p<005). WC also showed the best performance to identify metabolic syndrome in both genders (areas under the curve (AUCs): 0.79 and 0.76 for male and female, respectively), while BAI proved to be an inadequate indicator (AUCs: 0.63 and 0.67 for males and females), respectively, in this population.

CONCLUSIONS

The central adiposity measure (WC) had the best performance to identify metabolic syndrome, and it is a convenient, cheap and reliable tool that can be used in clinical practice routinely to prevent cardiovascular complications in HIV patients.

Remineralizing agents: effects on acid-softened enamel

This study sought to evaluate whether remineralizing toothpastes can protect acid-softened enamel against further erosive episodes. Fifty enamel slabs of bovine teeth with preformed erosion-like lesions were randomly assigned to 1 control and 4 experimental groups (n = 10): group 1, nanohydroxyapatite (nanoHAp) dentifrice; group 2, arginine and calcium carbonate (CaCO3) dentifrice; group 3, potassium nitrate (KNO3) and high-fluoride (F) availability dentifrice; group 4, ordinary fluoridated dentifrice (OFD); and group 5, control (deionized water). Initial hardness measurements were taken after the different treatments were applied. Statistically significant mineral gains of 8.0% and 10.0% were exhibited in groups 1 and 4, respectively. Groups 2 and 3 showed mineral gains of 4.5% and 2.1%, respectively; these were not statistically significant. Group 5 showed mineral loss (-11.8%). A 1-way analysis of variance showed no statistically significant differences in the mean microhardness values among groups. However, there are indications that the nanoHAp and OFD toothpastes may decrease erosive lesions after treatment, while the arginine + CaCO3 and KNO3 + F pastes may prevent the progression of erosive lesions.

[Growth of preterm infants]

A hundred-forty-one infants born from 26 to 36 weeks, appropriate-for-gestational-age, were followed from birth until the corrected postmenstrual age of 42 weeks. Weight, height and cephalic perimeter were measured on a weekly basis. Based on the average values and percentiles of these measurements it was adjusted a third degree polynomial function. The growth curves obtained, when compared with the so-called intra-uterine growth curves, showed that during the 40th and 42nd postmenstrual weeks the averages and medians are similar. It was observed that the growth dynamics of the preterm infants showed a catch-up pattern in the immediate postnatal period.