Trudy R. Turner

Variable responses of human and non-human primate gut microbiomes to a Western diet

BackgroundThe human gut microbiota interacts closely with human diet and physiology. To better understand the mechanisms behind this relationship, gut microbiome research relies on complementing human studies with manipulations of animal models, including non-human primates. However, due to unique aspects of human diet and physiology, it is likely that host-gut microbe interactions operate differently in humans and non-human primates.ResultsHere, we show that the human microbiome reacts differently to a high-protein, high-fat Western diet than that of a model primate, the African green monkey, or vervet (Chlorocebus aethiops sabaeus). Specifically, humans exhibit increased relative abundance of Firmicutes and reduced relative abundance of Prevotella on a Western diet while vervets show the opposite pattern. Predictive metagenomics demonstrate an increased relative abundance of genes associated with carbohydrate metabolism in the microbiome of only humans consuming a Western diet.ConclusionsThese results suggest that the human gut microbiota has unique properties that are a result of changes in human diet and physiology across evolution or that may have contributed to the evolution of human physiology. Therefore, the role of animal models for understanding the relationship between the human gut microbiota and host metabolism must be re-focused.

Mapping correlates of parasitism in wild South African vervet monkeys (Chlorocebus aethiops)

A growing focus of nonhuman primate conservation and management planning concerns factors affecting the dynamics of parasite infection and disease transmission. Here, we examine the effects of anthropogenic and environmental components of the landscape on the prevalence, richness, and species diversity of gastrointestinal parasites in wild-caught vervet monkeys (Chlorocebus aethiops) in South Africa. Nematodes of the genus Trichuris and the family Strongylidae and protists of the subclass Coccidia were present in 55.13% of sampled animals (n = 43). Parasitological, geographical, demographic and climatic correlates of infection were assessed in a geographical information systems (GIS) platform. The findings of this study suggest that parasitism in South African vervets may be better predicted by environmental factors than by degree of anthropogenic contact. This research represents one of the first surveys of parasitic infection in a wild monkey species in southern Africa.

Adult age confounds estimates of static allometric slopes in a vertebrate.

In many animal groups, the size of male genitalia scales shallowly with individual body size. This widespread pattern appears to admit some exceptions. For instance, steep allometries have been reported for vertebrate genitalia. This exception, however, may be due to a confounding effect arising from the continued growth of some structures during adulthood in vertebrates. Consider the possibility that genitalia continue to grow in adults while body size does not. If so, taking measurements from adults of different ages could yield steeper allometries than would be obtained from measurements of adults of the same age. We used vervet monkeys to test this hypothesis. We found that all body parts continued to grow in adult vervet monkeys, with sexual traits (including genitalia) showing faster growth rates. Traits with faster growth rates over adult ages had steeper allometries. And accounting for variation in adult age yielded shallower allometries, bringing vervet monkey genitalia in line with the predominant pattern observed in other animal groups. These results suggest that steep allometric slope estimates reported for other vertebrates may be due in part to mixing of adult ages, and reinforces one of the most consistent patterns yet detected in the study of static allometry.