Biology subjects

Siqueira-Silva, D. H.

Publications and source records attributed to Siqueira-Silva, D. H..

3 recordsLinked to original sources

bioRxiv2026

The anxiolytic-like effect of the aqueous extract of Punica granatum depends on the stress level of fish and mice: Evidence of a homeostatic re-establishing effect

Pomegranate (Punica granatum) has shown potential anxiolytic and antidepressant effects in preclinical research, but its mechanisms remain unclear. Importantly, some evidence suggests that the effects of P. granatum depend on previous stress, suggesting an adaptogenic effect. This study aimed to evaluate the anxiolytic-like effects of an aqueous extract of P. granatum (AE-PG) on lambaris and zebrafish exposed to acute restraint stress (ARS) and female BALB/c mice exposed to unpredictable chronic mild stress (CUMS). In addition, we evaluated antidepressant-like effects in female BALB/c mice. Acute administration of AE-PG (1 mg/kg, i.p.) was tested in the novel tank test (NTT) in lambaris and zebrafish and in the light/dark test (LDT) in zebrafish, while chronic (7 days) administration of AE-PG (1 mg/kg, i.p.) was tested in the elevated plus-maze (EPM), open-field test (OFT), splash test (ST), and forced swim test (FST) in mice. ARS increased geotaxis and erratic swimming in the NTT, as well as scototaxis, risk assessment, and erratic swimming in the LDT. Acute pre-treatment with AE-PG blocked the effects of ARS on these anxiety-like endpoints in both lambaris and zebrafish. CUMS increased open arm avoidance in the EPM, thigmotaxis and horizontal and vertical exploration in the OFT, and immobility in the FST, and decreased grooming in the ST. Chronic treatment with AE-PG blocked the effects of CUMS on anxiety-like endpoints, and depression-like endpoints, in mice. An in silico analysis of the main compounds in AE-PG suggested a possible mechanism of action on a wide network of targets that converge on PI3K/Akt and show differential expression in brain regions associated with fear- and anxiety-like behavior. Molecular docking suggests that a compound from AE-PG, ellagic acid, is likely to act through estrogen receptors, which could help reestablish homeostatic balance in response to stress.

pharmacology and toxicology↗

bioRxiv2020

EMBRYONIC DEVELOPMENT OF THE FIRE-EYE-TETRA Moenkhausia oligolepis (CHARACIFORMES: CHARACIDAE)

This study describes the embryonic development of Moenkhausia oligolepis in captive conditions. After fertilization, the embryos were collected every 10 min up to 2 h, every 20 min up to 4 h, and every 30 min until hatching. The fertilized eggs of M. oligolepis measured approximately 0.85 {+/-} 0.5 mm and have an adhesive surface. The embryonic development lasted 14 hours at 25{degrees}C, with the Zygote, Cleavage, Blastula, Gastrula, Neurula and Segmentation phases. The hatching occurred in embryos around the 30-somites stage. Our results bring only the second description of embryonic development to a species of Moenkhausia genus, the first for the refereed species. Such data are of paramount importance considering the current conflicting state of this genus phylogenetic classification and may help taxonomic studies. Understand the biology of a species that is easily handling in captive conditions and has an ornamental appeal may assist studies in its reproduction in order to both, supply the aquarium market and help the species conservation in nature. Moreover, our data enable the M. oligolepis to be used as a model species in biotechnological applications, such germ cell transplantation approach.

developmental biology↗

bioRxiv2019

Factors affecting secondary sex characteristics in the yellowtail tetra Astyanax altiparanae

This work aimed to analyze factors affecting secondary sexual characteristics in the yellowtail tetra Astyanax altiparanae. For this, seventy-five specimens were first separated into three different size classes (small, medium and large groups) between two seasons, summer and winter. In all groups, male fish were consistently bigger in the summer. On the other hand, females from both seasons presented in media the same length into the length classes. Afterwards, we performed histological analyses of the gonads to first confirm the genus and investigate the phase of maturation of each animal. During the winter, most of the small animals were males (22), most of the large animals, females (23), and the medium size animals followed a tendency of 1:1 ratio (9 male: 16 female). In the summer, male were the majority in both small (20) and medium (20) size. Larger-size animals were female (23). Then, in order to analyze the influence of genus, phase of maturation, season of the year, the number, and length of the animals spinelets, we diaphanized, counted, and measured them in each animal. Our results demonstrated that the spinelets are a sexual secondary characteristic of male genus independently of the size, season and phase of maturation. However, some tendencies were observed. Males bigger than 48 mm always presented spinelets; their size are in media the double in summer in comparison to winter; and summer males presents more rays with spinelets in the summer. Curiously, the larger specimen sampled was a female presenting spinelets in five rays. Lastly, we performed the gonadectomization of the animals and hypothesized that gonad hormones will directly influence this characteristic. The gonadectomization only initially influence on the size and number of spinelets in the anal fin rays, since the thirty-day-gonadectomized animals presented few and smaller spinelets against the control ones. However, the spinelets normalized in ninety-day-gonadectomized specimens. Such a work showed spinelets can be considered a secondary sexual characteristic to distinct male from female and can be used in the management in specimens bigger than 48 mm, but cannot indicate fish sterility.\n\nSummary statementThis study elucidated whether the size, sex, environmental conditions, and gonadal development affect the development of spinelets, a bony structure presented in anal fins in mature fish. Additionally, gonadectomized fish were used to elucidate the effect of gonad on the rise of such structures. Interesting new data showed that such a secondary sex characteristic is influenced by sex, size, gonadal development, and season of the year, but spinelets arose even within gonadectomized fish; this suggests that such a structure is not indicative of sterility in this species.

physiology↗