RESUMEN

This work focuses on the distribution of LINE-1 (a Long Interspersed Nuclear Element) in primates and its role during evolution and as a constituent of the architecture of primate genomes. To pinpoint the LINE-1 repeat distribution and its role among primates, LINE-1 probes were mapped onto chromosomes of Homo sapiens (Hominidae, Catarrhini), Sapajus apella, and Cebus capucinus (Cebidae, Platyrrhini) using fluorescence in situ hybridisation (FISH). The choice of platyrrhine species are due to the fact they are taxa characterised by a high level of rearrangements; for this reason, they could be a useful model for the study of LINE-1 and chromosome evolution. LINE-1 accumulation was found in the two Cebidae at the centromere of almost all acrocentric chromosomes 16-22 and on some bi-armed chromosomes. LINE-1 pattern was similar in the two species but only for chromosomes 6, 8, 10, and 18, due to intrachromosomal rearrangements in agreement with what was previously hypothesised as through g banding. LINE-1 interstitial accumulation was found in humans on the 1, 8, 9, 13-15, and X chromosomes; on chromosomes 8, 9, and 13-15, the signal was also at the centromeric position. This is in agreement with recent and complete molecular sequence analysis of human chromosomes 8 and some acrocentric ones. Thus, the hypothesis regarding a link between LINE-1 and centromeres as well as a link with rearrangements are discussed. Indeed, data analysis leads us to support a link between LINE-1 and inter- and intrachromosomal rearrangements, as well as a link between LINE-1 and structural functions at centromeres in primates.

Asunto(s)

RESUMEN

Gastric cancer (GC) is the fifth most common type of tumor and the third leading cause of cancer death worldwide. The evolution of gastric carcinogenesis is still poorly understood and, for this reason, preclinical research protocols were established that included the development of gastric cancer cell lines and the establishment of models of gastric carcinogenesis in non-human primates such as Sapajus apella. A comprehensive literature search was performed in relevant databases such as PubMed, ResearchGate, and Google Scholar to identify studies related to the topic. After an in-depth study of these reports, significant data were collected and compiled under appropriate headings. The main result of the studies carried out by the group on GC is the demonstration of the MYC gene overexpression as a common phenomenon in stomach carcinogenesis. Furthermore, we revealed that reducing the expression of the CDC25B gene, regulated by the MYC protein, is a therapeutic strategy against stomach tumors. This review article reveals preclinical evidence that treatment with menadione in experimental models of gastric tumorigenesis, in vivo and in vitro, inhibits the action of the phosphatase CDC25B and, consequently, prevents cell proliferation, invasion, and migration.

Asunto(s)

RESUMEN

Cannibalism is a quite common behaviour in animals that can have survival value when food is scarce or in the case of overpopulation. Conversely, cannibalism can also increase pathogen transmission and reduce fitness. In primates, some cases of cannibalism are associated with infanticide or are performed by mothers after their newborn has died (filial cannibalism). We report here the first observation of cannibalism, specifically infant cannibalism, in a semi-free-ranging group of brown capuchin monkeys (Sapajus apella). The baby was likely stillborn, as parts of the cranial bones were missing and no fresh injuries were visible. After half a day of taking care of the dead infant, the mother ate part of the corpse's skin and the highly nutritional viscera, possibly thereby compensating for the physiological costs of pregnancy. After attentively watching his mother's behaviour, the older brother of the dead newborn similarly ate parts of the corpse. Although we cannot rule out idiosyncrasy and vertical social transmission, it is possible that cannibalism is a normal-albeit rare-part of the behavioural repertoire of capuchin monkeys.

Asunto(s)

RESUMEN

The understanding that the perceptual appearance of the environment can differ in several ways from the reality underlies the ability to discriminate appearance from reality. Being able to realize when a misperception can lead us to behave in inappropriate ways confers an evolutionary advantage and may be a prerequisite to develop a Theory of Mind. Understanding that our own perception can differ from reality seems indeed necessary to attribute to others perceptions or beliefs different than ours. This appearance-reality discrimination ability has recently been demonstrated in great apes but no information is currently available regarding this ability in other nonhuman species. In a comparative study, we tested Tonkean macaques (Macaca tonkeana), an Old World primate species, and brown capuchins (Sapajus apella), a New World primate species. We provided monkeys with two experiments using visual illusions of size and quantity to test their ability to discriminate appearance from reality, with an experimental setup similar to the one developed by Krachun et al. (2016) on chimpanzees. A large number of brown capuchins, from different ages and both sexes, as well as two Tonkean macaques succeeded in the two experiments. By ruling out all alternative explanations (i.e. visual tracking or associative learning), our study brings the first evidence that some Old World and New World monkeys are able to discriminate appearance from reality. Our results suggest moving the evolutionary apparition of this cognitive ability earlier in time. Finally, it suggests that humans could share more Theory of Mind components with more nonhuman species than we previously thought.

Asunto(s)

RESUMEN

Background: Gastric cancer is one of the most incident types of cancer worldwide and presents high mortality rates and poor prognosis. MYC oncogene overexpression is a key event in gastric carcinogenesis and it is known that its protein positively regulates CDC25B expression which, in turn, plays an essential role in the cell division cycle progression. Menadione is a synthetic form of vitamin K that acts as a specific inhibitor of the CDC25 family of phosphatases. Methods: To better understand the menadione mechanism of action in gastric cancer, we evaluated its molecular and cellular effects in cell lines and in Sapajus apella, nonhuman primates from the new world which had gastric carcinogenesis induced by N-Methyl-N-nitrosourea. We tested CDC25B expression by western blot and RT-qPCR. In-vitro assays include proliferation, migration, invasion and flow cytometry to analyze cell cycle arrest. In in-vivo experiments, in addition to the expression analyses, we followed the preneoplastic lesions and the tumor progression by ultrasonography, endoscopy, biopsies, histopathology and immunohistochemistry. Results: Our tests demonstrated menadione reducing CDC25B expression in vivo and in vitro. It was able to reduce migration, invasion and proliferation rates, and induce cell cycle arrest in gastric cancer cell lines. Moreover, our in-vivo experiments demonstrated menadione inhibiting tumor development and progression. Conclusions: We suggest this compound may be an important ally of chemotherapeutics in the treatment of gastric cancer. In addition, CDC25B has proven to be an effective target for investigation and development of new therapeutic strategies for this malignancy.

RESUMEN

BACKGROUND: Oculocutaneous Albinism (OCA) is an autosomal recessive inherited condition that affects the pigmentation of eyes, hair and skin. The OCA phenotype may be caused by mutations in the tyrosinase gene (TYR), which expresses the tyrosinase enzyme and has an important role in the synthesis of melanin pigment. The aim of this study was to identify the genetic mutation responsible for the albinism in a captive capuchin monkey, and to describe the TYR gene of normal phenotype individuals. In addition, we identified the subject's species. RESULTS: A homozygous nonsense mutation was identified in exon 1 of the TYR gene, with the substitution of a cytosine for a thymine nucleotide (C64T) at codon 22, leading to a premature stop codon (R22X) in the albino robust capuchin monkey. The albino and five non-albino robust capuchin monkeys were identified as Sapajus apella, based on phylogenetic analyses, pelage pattern and geographic provenance. One individual was identified as S. macrocephalus. CONCLUSION: We conclude that the point mutation C64T in the TYR gene is responsible for the OCA1 albino phenotype in the capuchin monkey, classified as Sapajus apella.

Asunto(s)

RESUMEN

BACKGROUND: This study aimed to evaluate, by B-mode ultrasound and Doppler ultrasound, the kidneys of one Neotropical primate maintained in captivity. METHODS: Ten adult intact tufted capuchins (Sapajus apella) were evaluated. The morphometric parameters of both kidneys were evaluated and kidney volumes calculated. Color Doppler was used to evaluate renal vascular architecture and to identify arteries of the left kidney. Spectral Doppler was used to measure peak-systolic velocity, end-diastolic velocity, and resistive index (RI). RESULTS: Both kidneys presented homogeneous cortical echogenicity and homogeneous echotexture with preserved corticomedullary differentiation. There was no statistically significant difference between right and left kidneys for all morphometric parameters. RI of the left renal, interlobar, and arcuate arteries were, respectively, 0.75 (SD, 0.07), 0.70 (SD, 0.08), and 0.70 (SD, 0.06). CONCLUSIONS: Both kidneys showed similar morphometric parameters by B-mode ultrasound, whereas RI by spectral Doppler decreased progressively from renal artery to interlobar and arcuate arteries.

Asunto(s)

RESUMEN

Behavioural responses to photos are often used to infer what animals understand about their social environment, but are rarely validated against the same stimuli in real life. If subjects' responses to photos do not reflect responses to the same live stimuli, it is difficult to conclude what happens in reality based on photo responses alone. We compared capuchins' responses to photos versus live stimuli in an identical scenario within research cubicles. Subjects had the opportunity to approach food placed in front of an alpha group member and, in a separate condition, photos depicting the same individual. Subjects' latencies to approach food when placed in front of the real alpha negatively correlated with time subjects spent in close proximity to the alpha in their main enclosure. We therefore predicted subjects' latencies to approach food in the presence of photos would positively correlate with their latencies to approach food in the presence of the real alpha inside the cubicles, but negatively correlate with time they spent in proximity to the alpha in their enclosure. Neither prediction was supported. While not necessarily surprising, we explain why these results should be an important reminder that care is needed when interpreting results from photo studies.

Asunto(s)

RESUMEN

Recent dental microwear studies have shown that fossil species differ from one another in texture attributes-both in terms of central tendency and dispersion. Most comparative studies used to interpret these results have relied on poorly provenienced museum samples that are not well-suited to consideration of within species variation in diet. Here we present a study of two species of platyrrhine monkeys, Alouatta belzebul (n = 60) and Sapajus apella (n = 28) from Pará State in the Brazilian Amazon in order to assess effects of habitat variation on microwear (each species was sampled from forests that differ in the degree of disturbance from highly disturbed to minimally disturbed). Results indicate that microwear texture values vary between habitats-more for the capuchins than the howler monkeys. This is consistent with the notion that diets of the more folivorous A. belzebul are less affected by habitat disturbance than those of the more frugivorous S. apella. It also suggests that microwear holds the potential to reflect comparatively subtle differences in within-species variation in fossil taxa if sample size and control over paleohabitat allow.

Asunto(s)

RESUMEN

Sapajus apella is a wild monkey of South America distributed across almost all of Brazil. This species adapts to domesticated life and reproduces easily. The present study describes the macro- and microscopic morphology of male genital organs (penis, penis bone, glans penis, prepuce, bulb of penis, and urethra) of Sapajus apella. Four male monkeys were used in this study. For macroscopic description, the genitals were dissected, examined and photographed. For microscopic analysis, samples were stained by HE and Tricom Masson and analyzed by scanning electron microscopy and light microscopy. The penis has a gutter shape with numerous spines on the free part of the penis and glans, and showed cavernous body elements in which mesenchymal cells appear. The glans penis is well developed with a broad crown shape. The prepuce does not cover the free part of the penis. The bulb displays well-developed muscle structure and the membranous urethra is very elongated. These results reveal that Sapajus apella shows specific male genital features, different from other primates.

Asunto(s)

RESUMEN

O objetivo desse trabalho foi contribuir com o estudo anatômico, morfométrico, ultraestrutural e propriedades físicas dos dentes permanentes do primata Sapajus apella. Para tal, foram utilizados 10 animais adultos e machos. Os dentes foram avaliados quanto ao seu comprimento e quanto à anatomia radicular externa e interna considerando número de raízes e canais, forma e direção radicular e forma do canal, assim como análise da densidade e diâmetro tubular do canal radicular, composição e microdureza dentinária. A anatomia radicular desse primata apresentou especificidades, como o número de raízes do segundo pré-molar superior e a presença do terceiro pré-molar. Quanto à densidade e o diâmetro dos túbulos dentinários, observou-se uma diminuição do número e diâmetro de túbulos ao longo do canal radicular, havendo diferença estatisticamente significante ao se comparar o terço apical com as regiões cervical e média, padrão de densidade e tamanho semelhantes a dentes humanos. Semelhanças também foram encontradas com dentes humanos quando comparados os valores de microdureza e proporção de elementos químicos encontrados na dentina radicular...

This paper aimed the anatomical study including morphometric, ultrastructural and physical properties of permanent teeth of Sapajus apella primate. Ten adult male monkeys were studied. The teeth were evaluated for their length, root anatomy (external and internal considering the number of roots and canals), direction and shape of the root canal, density and diameter of the tubular root canal, dentin microhardness, and composition. The root anatomy showed specificity regarding the number of roots of the second premolar and the presence of the third premolar. We observed a decrease in the number and diameter of dentinal tubules along the root canal, a statistically significant difference when compared with the apical and cervical regions. Similarities with human teeth were found in regard to microhardness values and proportion of chemical elements in the root dentin...

Asunto(s)

RESUMEN

This study compared the motivation of the blue and yellow macaw (n=8) and the tufted capuchin (n=3) to manipulate objects that presented different features, their manipulative repertoires, and their ability to solve complex manipulation tasks. Results show that both species seem to be more motivated to manipulate objects that look like food items and that manipulative behavior may be considered as play behavior in the blue and yellow macaws, and would improve foraging motor skills. The tufted capuchins performed more different action styles than the macaws when manipulating objects, and performed substrate-use behavior - the object is put in relationship with a substrate - while the macaws did not. This is an interesting difference because these characteristics are supposed to be precursory of tool-use, behavior never observed in this macaw species. It may be due to the arboreal lifestyle of the macaw and its neophobic character that do not allow it to easily contact objects. Following the same method and using more individuals, further comparative studies should be conducted in order to test these hypotheses. Both species were able to solve complex manipulation tasks.

Asunto(s)