DSpace Coleção: Artigo em periódico indexado (CNPGL)

Leishmanicidal and immunomodulatory effects of Ocellatin-PT4 and Ocellatin-PT6 on amastigotes of Leishmania amazonensis.

2026-01-01T00:00:00Z

Título: Leishmanicidal and immunomodulatory effects of Ocellatin-PT4 and Ocellatin-PT6 on amastigotes of Leishmania amazonensis. Autoria: OLIVEIRA, M. G. C.; ESCHIMITH, V. da S.; KUZNIEWSKI, F. T. B.; VASCONCELOS, A. G.; MOREIRA, D. C.; BEMQUERER, M. P.; CORAZZA, D.; DIAS, J. N.; ARCANJO, D. D. R.; EATON, P.; MUNIZ-JUNQUEIRA , M. I.; LEITE, J. R. S. A.; BORGES, T. K. S.; KUCKELHAUS, S. A. S. Conteúdo: Background/Objectives: Leishmaniasis is a neglected parasitic disease with significant global impact and limited therapeutic options due to the toxicity and cost of current treatments. Antimicrobial peptides (AMPs) derived from amphibians, such as Ocellatin-PT4 and Ocellatin-PT6, have emerged as promising bioactive molecules due to their antimicrobial properties and low toxicity to mammalian cells. This study evaluated the leishmanicidal and immunomodulatory effects of Ocellatin-PT4 and Ocellatin-PT6 against Leishmania amazonensis amastigotes. Methods: Peptides were tested on axenic amastigotes and macrophages infected with amastigotes. Cytotoxicity was assessed using MTT (0.4–197 µM for Ocellatin-PT4 and 0.3–152.1 µM for Ocellatin-PT6) and vital dye exclusion assays. Reactive oxygen species (ROS), nitric oxide (NO), and lipid droplet (LD) production were quantified to assess immunomodulatory responses. Results: Ocellatin-PT4 and Ocellatin-PT6 significantly reduced the viability of free and intracellular amastigotes at concentrations ≥ 24.7 µM and ≥19 µM, respectively, without affecting J774 macrophage viability. Infected macrophages treated with the peptides showed reduced parasite load and decreased infection index (≥12.3 µM for Ocellatin-PT4 and ≥2.4 µM for Ocellatin-PT6). Both peptides modulated the oxidative stress response: they reduced ROS levels in infected macrophages while only slightly increasing NO production at higher concentrations. Additionally, lipid droplet accumulation, which was increased during infection, was downregulated by both peptides—particularly by Ocellatin-PT6. Conclusions: Ocellatin-PT4 and Ocellatin-PT6 exert leishmanicidal effects and modulate key macrophage functions without cytotoxicity. These peptides represent promising candidates for the development of novel therapies against cutaneous leishmaniasis.

Expression of apomixis genes during reproductive development in Urochloa decumbens and Urochloa ruziziensis (Poaceae).

2026-01-01T00:00:00Z

Título: Expression of apomixis genes during reproductive development in Urochloa decumbens and Urochloa ruziziensis (Poaceae). Autoria: ROCHA, M. J. da; DAMASCENO, A. G.; DIOGO JUNIOR, R.; SANTOS, H. O. dos; SOUZA SOBRINHO, F. de; TECHIO, V. H.; PEREIRA, W. A. Conteúdo: This study aimed to correlate the developmental stages of the embryo sac with the morphometric traits of spikelets and to characterize the expression of the BbrizRan, BbrizSti1, and BbrizAGL6genes in Urochloa ruziziensis(sexual) and U. decumbens(apomictic). Data on the length and diameter of spikelets and anatomical sections were also obtained. Gene expression was determined using RT-qPCR in spikelets at megasporogenesis and megagametogenesis. The spikelet length could be used as a reliable morphological marker to discriminate between the two stages in both species. The embryo sacs observed were of the Polygonumtype in U. ruziziensisand the Panicumtype in U. decumbens. RT-qPCR analysis revealed that the BbrizRan, BbrizSti1, and BbrizAGL6genes were differentially expressed in the studied species during reproductive development. The BbrizSti1gene was more highly expressed in U. decumbens(apomictic) than in U. ruziziensis(sexual) during megasporogenesis, while for BbrizRan, U. decumbensshowed higher expression than U. ruziziensisduring both megasporogenesis and megagametogenesis. An increase in the expression level of BbrizAGL6was observed in both species at both developmental stages ofthe embryo sac.

Effects of human chorionic gonadotropin on echotextural attributes of the original corpus luteum in Morada Nova ewes.

2026-01-01T00:00:00Z

Título: Effects of human chorionic gonadotropin on echotextural attributes of the original corpus luteum in Morada Nova ewes. Autoria: GONÇALVES, J. D.; VERGANI, G. B.; RODRIGUES, J. N. D.; DIAS, J. H.; PEREIRA, V. S. do A.; GARCIA, A. R.; ESTEVES, S. N.; FONSECA, J. F. da; OLIVEIRA, M. E. F. Conteúdo: This study evaluated whether human chorionic gonadotropin (hCG) affects biometric, echotextural, and signs color Doppler variables of the original corpus luteum (oCL) in Morada Nova ewes. Sixty-four ewes underwent estrus synchronization with intravaginal sponges impregnated with 60 mg of medroxyprogesterone acetate for six days, with an intramuscular injection of 37.5 µg of d-cloprostenol and 200 IU of equine chorionic gonadotropin thirty-six hours before sponge removal. The ewes were subjected to natural mating and subsequently allocated to receive 300 IU of hCG (hCG group; n=34) or 1 mL of saline solution (Control group; n=30) intramuscularly 7.5 days after sponge removal. Biometric variables of the corpus luteum (diameter, area, volume), echotextural variables (numerical pixels values and heterogeneity), and color Doppler signals (color Doppler area, color Doppler volume, and percentage of perfusion) were evaluated on days 7.5, 10.5, 13.5, and 21.5 after sponge removal. The oCL showed no differences in biometric or color Doppler signals between the hCG and control groups (P>0.05). However, hCG increased the echotextural variables, with oCL exhibiting higher numerical pixel values (88.8±4.7a vs. 70.0±0.8b ; P=0.0001) and heterogeneity (14.3±0.6a vs. 11.5±0.2b 38; P<0.0001) compared to the control 39 oCL, respectively. Furthermore, this increased echotextural variables was also observed in pregnant females with oCL hCG when compared to pregnant females with oCL control (P<0.05). These findings indicate that hCG enhances echotextural attributes of the oCL, suggesting functional improvement rather than structural or vascular changes during the early luteal phase.

Prevention of renal and genital leptospirosis in experimentally infected ewes by vaccination.

2026-01-01T00:00:00Z

Título: Prevention of renal and genital leptospirosis in experimentally infected ewes by vaccination. Autoria: LORIA, J.; EZEPHA, C.; ROUSSOULIÉRES, I.; SOUZA, G. N. de; SARDI, F.; ALONZO, P.; LILENBAUM, W. Conteúdo: Infection by Leptospira sp. caused by strains of serogroup Sejroe impairs ruminants’ reproductive efficiency. Control of leptospirosis is complex, and although systemic vaccination minimizes the clinical effects of the disease, the protection against genitourinary colonization is still controversial. Therefore, the present study aims to assess the efficacy of vaccines against L. borgpetersenii serovar Hardjo in preventing renal and genital leptospirosis in experimentally infected ewes. Twenty-four adult Santa Inˆes ewes were divided into four groups (N = 6 each), where Groups 1, 2, and 3 were vaccinated with two doses before challenge (on D-43 and D-15) and Group 4 remained unvaccinated. Groups 1 and 2 received experimental vaccines formulated with the same antigen (L. borgpetersenii sv Hardjo), but with different adjuvants (aluminum hydroxide and mineral emulsion adjuvant, respectively). In contrast, Group 3 received a commercial multivalent vaccine. On D0, all animals were challenged via the genital route with 108 leptospires (L. borgpetersenii serogroup Sejroe, serovar Hardjo). Microscopic Agglutination Test was performed on day D-43, D-15, D0, D7, D14, D21, D30, and D60. Quantitative analysis of urinary and reproductive tract colonization was performed using qPCR of urine and cervicovaginal mucus collected on the same days. The results demonstrate that, although vaccination did not completely prevent kidney colonization, Vac2 (mineral oil) and Vac3 (multivalent) reduced the bacterial load and the number of infected animals throughout the experiment. Regarding genital colonization, Vac2 stimulated an immune response that cleared the infection of all ewes at D30 onwards, presenting an interesting potential for protection of the genital tract.