Intravenous gene transfer throughout the brain of infant Old World primates using AAV

Adeno-associated viruses (AAVs) can enable robust and safe gene delivery to the mammalian central nervous system (CNS). While the scientific community has developed numerous neurotropic AAV variants for systemic gene-transfer to the rodent brain, there are few AAVs that efficiently access the CNS of higher order primates. We describe here AAV.CAP-Mac, an engineered AAV variant that enables systemic, brain-wide gene delivery in infants of two Old World primate species--the rhesus macaque (Macaca mulatta) and the green monkey (Chlorocebus sabaeus). We identified CAP-Mac using a multi-species selection strategy, initially screening our library in the adult common marmoset (Callithrix jacchus) and narrowing our pool of test-variants for another round of selection in infant macaques. In individual characterization, CAP-Mac robustly transduces human neurons in vitro and Old World primate neurons in vivo, where it targets all lobes of cortex, the cerebellum, and multiple subcortical regions of disease relevance. We use CAP-Mac for Brainbow-like multicolor labeling of macaque neurons throughout the brain, enabling morphological reconstruction of both medium spiny neurons and cortical pyramidal cells. Because of its broad distribution throughout the brain and high neuronal efficiency in infant Old World primates compared to AAV9, CAP-Mac shows promise for researchers and clinicians alike to unlock novel, noninvasive access to the brain for efficient gene transfer.

Hand Preference in Rhinopithecus roxellana Infants: Is It Influenced by Familial Inheritance?

The Sichuan snub-nosed monkey (Rhinopithecus roxellana) is a typical arboreal group-living Old-World primate and has been studied broadly in hand preference. However, infants have not been tested independently from other immature individuals to date. The purpose of the present study was to investigate hand preference in a spontaneously unimanual feeding task in nine infants at 12 months and the relationship of hand preference with their parents in R. roxellanae. Most infants (89%) showed individual-level hand preference. No correlation was found in the direction of hand preference between infant and its parents, and a significant negative correlation in the strength of hand preference was found between infants and their mothers (r = −0.715, p = 0.03). Moreover, there was no sex difference in the direction and strength of hand preference both in infants and adults (i.e., parents). Meanwhile, the strength of hand preference in adults was stronger than that in infants. This study is a first and preliminary exploration for the expression of hand preference in R. roxellanae infants and whether their hand preference was influenced by familial inheritance.

Female copulation calls vary with male ejaculation in captive olive baboons

Copulation calls are mating-associated vocalizations that are common in primates, with females vocalizing after copulation in several Old World monkeys and apes. Baboon females typically produce copulation calls that correlate with fertile phase. Calls are, thus, regarded as an upshot of cycle physiology and sexually selected calls. Here, we describe three captive troops of olive baboons wherein, against expectation, females suppressed vocalizing during copulations. Vaginal cytology, together with sexual swelling observations, confirmed that females experienced full receptive cycles. Ovulation did not affect vocal probability during sex, while copulation calls were predicted by male ejaculation just as in other Old World primate species. Results cast doubt on the existence of physiological triggers for baboon copulation calls. Social factors may instead play a larger role. Alterations in social structure (as typically observed in the wild) may be implemented strategically as captive enrichment in order to reveal how females in highly social primates change sexual strategies and, therefore, the use of their copulation calls.

Long-lasting vocal plasticity in adult marmoset monkeys

Humans exhibit a high level of vocal plasticity in speech production, which allows us to acquire both native and foreign languages and dialects, and adapt to local accents in social communication. In comparison, non-human primates exhibit limited vocal plasticity, especially in adulthood, which would limit their ability to adapt to different social and environmental contexts in vocal communication. Here, we quantitatively examined the ability of adult common marmosets ( Callithrix jacchus ), a highly vocal New World primate species, to modulate their vocal production in social contexts. While recent studies have demonstrated vocal learning in developing marmosets, we know much less about the extent of vocal learning and plasticity in adult marmosets. We found, in the present study, that marmosets were able to adaptively modify the spectrotemporal structure of their vocalizations when they encountered interfering sounds. Our experiments showed that marmosets shifted the spectrum of their vocalizations away from the spectrum of the interfering sounds in order to avoid the overlap. More interestingly, we found that marmosets made predictive and long-lasting spectral shifts in their vocalizations after they had experienced a particular type of interfering sound. These observations provided evidence for directional control of the vocalization spectrum and long-term vocal plasticity by adult marmosets. The findings reported here have important implications for the ability of this New World primate species in voluntarily and adaptively controlling their vocal production in social communication.

Anatomical study of the origin and area of innervation that form the brachial plexus of monkey-nail (Sapajus libidinosus)

We studied, and herein describe, the anatomy of the brachial plexus in the Sapajus libidinosus, a New World primate species. The study of origin and distribution of the nerves that form the brachial plexus of primates contributes to the body of knowledge of veterinary functional anatomy, and can have important ramifications to clinical, surgical, and anesthetic procedures, as well as to the understanding of injuries in these species. We found that the brachial plexus of Sapajus libidinosus is composed of neural fibers originating from the union of the dorsal and ventral roots of the cervical vertebral segments C5 to C8 and thoracic T1. These fibers then are organized in four main trunks, with a subdivision in the middle trunk. We concluded that the origins, trajectories and territory of innervation of the nerve trunks of the brachial plexus of Sapajus libidinosus are similar to those of other primates, with some variations occurring in the course.

First New World Primate Papillomavirus Identification in the Atlantic Forest, Brazil: Alouatta guariba papillomavirus 1

We report here the complete genome sequence of the first papillomavirus detected in a New World primate, howler monkey, Alouatta guariba clamitans papillomavirus 1 (AgPV1), from the Atlantic Forest in São Paulo State, Brazil.