Project description:Nursery rearing has well-known consequences for primate species. Relative to some other primate species, research has indicated a reduced impact of nursery rearing on squirrel monkeys, particularly in terms of rates, severity, and persistence of abnormal behavior. We administered the Primate Neonatal Neurobehavioral Assessment to 29 dam-reared and 13 nursery-reared squirrel monkeys (Saimiri boliviensis boliviensis) at 2 and 6 weeks of age. Mixed-model ANOVAs comparing composite scores and individual assessment items across age, rearing status, and sex revealed a number of developmental differences. Dam-reared infants scored higher on all four composite measures compared to nursery-reared infants (p < .05) indicating that nursery-reared animals had slower motor development, were less active and attentive, and were more passive than their dam-reared counterparts. Consistent with infant rhesus macaques, nursery-reared squirrel monkeys showed an increased sensitivity to tactile stimulation (p < .05). Altogether, these results suggest a disruption of species-typical development when squirrel monkey infants are reared in a nursery setting, with activity, orientation, and state control areas most affected, though experimental research is needed to determine if this is a causal relationship. Contrary to previous behavioral research, there are likely developmental differences between dam-reared infant squirrel monkeys and those reared in a nursery setting.
Project description:In the present study, we have quantified the effects of transport, relocation and acclimate/adapt to their new surroundings on female squirrel monkey. These responses are measured in blood samples obtained from squirrel monkeys, at different time points relative to their relocation from their old home to their new home. A group of squirrel monkeys we transported, by truck, for approximately 10 hours. Peripheral blood mononuclear cells (PBMCs) were assayed in order to evaluate the phenotype of lymphocyte subsets by flow, mitogen-specific immune responses of PBMCs in vitro, and levels of cytokines at various time points including immediately before transport, immediately upon arrival, and after approximately 150 days of acclimation. We observed significant changes in T cells and subsets, NK and B cells (CD4+, CD8+, CD4+/CD8+, CD16+, and CD20+). Mitogen specific (e.g. PHA, PWM and LPS) proliferation responses, IFN-γ by ELISPOT assay, and cytokines (IL-2, IL-4 and VEGF) significant changes were observed. Changes seen in the serum chemistry measurements mostly complement those seen in the hematology data. The specific goal was to empirically assess the effects of relocation stress in squirrel monkeys in terms of changes in the numbers and functions of various leukocyte subsets in the blood and the amount of time required for acclimating to their new environment. Such data will help to determine when newly arrived animals become available for use in research studies.
Project description:Unlike in Asia and Latin America, Plasmodium vivax infections were rare in Sub-Saharan Africa due to the absence of the Duffy blood group antigen (Duffy Antigen), the only known erythrocyte receptor for the P. vivax merozoite invasion ligand, Duffy Binding Protein 1 (DBP1). However, P. vivax infections have been documented in Duffy-negative individuals throughout Africa, suggesting that P. vivax may use ligands other than DBP1 to invade Duffy-negative erythrocytes through other receptors. To identify potential P. vivax ligands, we compared parasite gene expression in Saimiri and Aotus monkey erythrocytes infected with P. vivax Salvador I (Sal I). DBP1 binds Aotus but does not bind to Saimiri erythrocytes, and thus P. vivax Sal I must invade Saimiri erythrocytes independently of DBP1. Comparing RNA sequencing (RNAseq) data for late stage infections in Saimiri and Aotus erythrocytes when invasion ligands are expressed, we identified genes that belong to tryptophan-rich antigen and MSP3 families that were more abundantly expressed in Saimiri infections as compared to Aotus infections. These genes may encode potential ligands responsible for P. vivax infections of Duffy-negative Africans.