Use Of Conspecific Gestural Cues To Solve An Object-Choice Task In Tufted Capuchin Monkeys (Cebus Apella)

Capuchin monkeys, Cebus sp., utilize a wide array of gestural displays in the wild, including facial displays such as lip-smacking and bare-teeth displays. In captivity, they have been shown to respond to the head orientation of humans, show sensitivity to human attentional states, as well as follow human gazes behind barriers. In this study, I investigated whether tufted capuchin monkeys (Cebus apella) would attend to and utilize the gestural cues of a conspecific to obtain a hidden reward. Two capuchins faced each other in separate compartments of an apparatus with an open field in between. The open field contained two cups with holes on one side such that only one monkey, a so-called cuing monkey, could see the reward inside one of the cups. I then moved the cups toward the other signal-receiving monkey and assessed whether it would utilize untrained cues provided by the cuing monkey to select the cup containing the reward. Two of four female capuchin monkeys learned to select the cup containing the reward significantly more often than chance. Neither of these two monkeys performed over chance spontaneously, however, and the other two monkeys never performed above chance despite many blocks of trials. Successful choices by two monkeys to obtain hidden rewards provided experimental evidence that capuchin monkeys attend to and utilize the gestural cues of conspecifics.

The Use of Human and Conspecific Gestures By Capuchin Monkeys to Solve an Object-Choice Task

Most primates live in highly complex social systems, and therefore have evolved similarly complex methods of communicating with each other. One type of communication is the use of manual gestures, which are only found in primates. No substantial evidence exists indicating that monkeys use communicative gestures in the wild. However, monkeys may demonstrate the ability to learn and/or use gestures in certain experimental paradigms since they¿ve been shown to use other visual cues such as gaze. The purpose of this study was to investigate if ten brown capuchin monkeys (Cebus apella) were able to use gestural cues from monkeys and a pointing cue from a human to obtain a hidden reward. They were then tested to determine if they could transfer this skill from monkeys to humans and from humans to monkeys. One group of monkeys was trained and tested using a conspecific as the cue giver, and was then tested with a human cue-giver. The second group of monkeys began training and testing with a human cue giver, and was then tested with a monkey cue giver. I found that two monkeys were able to use gestural cues from conspecifics (e.g., reaching) to obtain a hidden reward and then transfer this ability to a pointing cue from a human. Four monkeys learned to use the human pointing cue first, and then transferred this ability to use the gestural cues from conspecifics to obtain a hidden reward. However, the number of trials it took for each monkey to transfer the ability varied considerably. Some subjects spontaneously transferred in the minimum number of trials needed to reach my criteria for successfully obtaining hidden rewards (N = 40 trials), while others needed a large number of trials to do so (e.g. N = 190 trials). Two subjects did not perform successfully in any of the conditions in which they were tested. One subject successfully used the human pointing cue and a human pointing plus vocalization cue, but did not learn the conspecific cue. One subject learned to use the conspecific cue but not the human pointing cue. This was the first study to test if brown capuchin monkeys could use gestural cues from conspecifics to solve an object choice task. The study was also the first to test if capuchins could transfer this skill from monkeys to humans and from humans to monkeys. Results showed that capuchin monkeys were able to flexibly use communicative gestures when they were both unintentionally given by a conspecific and intentionally given by a human to indicate a source of food.

"Self" and "nonself" manipulation of interferon defense during persistent infection: bovine viral diarrhea virus resists alpha/beta interferon without blocking antiviral activity against unrelated viruses replicating in its host cells

Bovine viral diarrhea virus (BVDV), together with Classical swine fever virus (CSFV) and Border disease virus (BDV) of sheep, belongs to the genus Pestivirus of the Flaviviridae. BVDV is either cytopathic (cp) or noncytopathic (ncp), as defined by its effect on cultured cells. Infection of pregnant animals with the ncp biotype may lead to the birth of persistently infected calves that are immunotolerant to the infecting viral strain. In addition to evading the adaptive immune system, BVDV evades key mechanisms of innate immunity. Previously, we showed that ncp BVDV inhibits the induction of apoptosis and alpha/beta interferon (IFN-alpha/beta) synthesis by double-stranded RNA (dsRNA). Here, we report that (i) both ncp and cp BVDV block the induction by dsRNA of the Mx protein (which can also be induced in the absence of IFN signaling); (ii) neither biotype blocks the activity of IFN; and (iii) once infection is established, BVDV is largely resistant to the activity of IFN-alpha/beta but (iv) does not interfere with the establishment of an antiviral state induced by IFN-alpha/beta against unrelated viruses. The results of our study suggest that, in persistent infection, BVDV is able to evade a central element of innate immunity directed against itself without generally compromising its activity against unrelated viruses ("nonself") that may replicate in cells infected with ncp BVDV. This highly selective "self" and "nonself" model of evasion of the interferon defense system may be a key element in the success of persistent infection in addition to immunotolerance initiated by the early time point of fetal infection.

Object-Oriented Legacy System Trace-based Logic Testing

When reengineering legacy systems, it is crucial to assess if the legacy behavior has been preserved or how it changed due to the reengineering effort. Ideally if a legacy system is covered by tests, running the tests on the new version can identify potential differences or discrepancies. However, writing tests for an unknown and large system is difficult due to the lack of internal knowledge. It is especially difficult to bring the system to an appropriate state. Our solution is based on the acknowledgment that one of the few trustable piece of information available when approaching a legacy system is the running system itself. Our approach reifies the execution traces and uses logic programming to express tests on them. Thereby it eliminates the need to programatically bring the system in a particular state, and handles the test-writer a high-level abstraction mechanism to query the trace. The resulting system, called TESTLOG, was used on several real-world case studies to validate our claims.

Adaptation to hard-object feeding in sea otters and hominins

The large, bunodont postcanine teeth in living sea otters (Enhydra lutris) have been likened to those of certain fossil hominins, particularly the ’robust’ australopiths (genus Paranthropus). We examine this evolutionary convergence by conducting fracture experiments on extracted molar teeth of sea otters and modern humans (Homo sapiens) to determine how load-bearing capacity relates to tooth morphology and enamel material properties. In situ optical microscopy and x-ray imaging during simulated occlusal loading reveal the nature of the fracture patterns. Explicit fracture relations are used to analyze the data and to extrapolate the results from humans to earlier hominins. It is shown that the molar teeth of sea otters have considerably thinner enamel than those of humans, making sea otter molars more susceptible to certain kinds of fractures. At the same time, the base diameter of sea otter first molars is larger, diminishing the fracture susceptibility in a compensatory manner. We also conduct nanoindentation tests to map out elastic modulus and hardness of sea otter and human molars through a section thickness, and microindentation tests to measure toughness. We find that while sea otter enamel is just as stiff elastically as human enamel, it is a little softer and tougher. The role of these material factors in the capacity of dentition to resist fracture and deformation is considered. From such comparisons, we argue that early hominin species like Paranthropus most likely consumed hard food objects with substantially higher biting forces than those exerted by modern humans.

Genetic and pharmacologic manipulation of oxidative stress after neonatal hypoxia-ischemia

Oxidative stress is a critical component of the injury response to hypoxia-ischemia (HI) in the neonatal brain, and this response is unique and at times paradoxical to that seen in the mature brain. Previously, we showed that copper-zinc superoxide-dismutase (SOD1) over-expression is not beneficial to the neonatal mouse brain with HI injury, unlike the adult brain with ischemic injury. However, glutathione peroxidase 1 (GPx1) over-expression is protective to the neonatal mouse brain with HI injury. To further test the hypothesis that an adequate supply of GPx is critical to protection from HI injury, we crossed SOD1 over-expressing mice (hSOD-tg) with GPx1 over-expressing mice (hGPx-tg). Resulting litters contained wild-type (wt), hGPx-tg, hSOD-tg and hybrid hGPx-tg/hSOD-tg pups, which were subjected to HI at P7. Confirming previous results, the hGPx-tg mice had reduced injury compared to both Wt and hSOD-tg littermates. Neonatal mice over-expressing both GPx1 and SOD1 also had less injury compared to wt or hSOD-tg alone. A result of oxidative stress after neonatal HI is a decrease in the concentration of reduced (i.e. antioxidant-active) glutathione (GSH). In this study, we tested the effect of systemic administration of alpha-lipoic acid on levels of GSH in the cortex after HI. Although GSH levels were restored by 24h after HI, injury was not reduced compared to vehicle-treated mice. We also tested two other pharmacological approaches to reducing oxidative stress in hSOD-tg and wild-type littermates. Both the specific inhibitor of neuronal nitric oxide synthase, 7-nitroindazole (7NI), and the spin-trapping agent alpha-phenyl-tert-butyl-nitrone (PBN) did not reduce HI injury, however. Taken together, these results imply that H2O2 is a critical component of neonatal HI injury, and GPx1 plays an important role in the defense against this H2O2 and is thereby neuroprotective.

Manipulation of antioxidant pathways in neonatal murine brain

To assess the role of brain antioxidant capacity in the pathogenesis of neonatal hypoxic-ischemic brain injury, we measured the activity of glutathione peroxidase (GPX) in both human-superoxide dismutase-1 (hSOD1) and human-GPX1 overexpressing transgenic (Tg) mice after neonatal hypoxia-ischemia (HI). We have previously shown that mice that overexpress the hSOD1 gene are more injured than their wild-type (WT) littermates after HI, and that H(2)O(2) accumulates in HI hSOD1-Tg hippocampus. We hypothesized that lower GPX activity is responsible for the accumulation of H(2)O(2). Therefore, increasing the activity of this enzyme through gene manipulation should be protective. We show that brains of hGPX1-Tg mice, in contrast to those of hSOD-Tg, have less injury after HI than WT littermates: hGPX1-Tg, median injury score = 8 (range, 0-24) versus WT, median injury score = 17 (range, 2-24), p < 0.01. GPX activity in hSOD1-Tg mice, 2 h and 24 h after HI, showed a delayed and bilateral decline in the cortex 24 h after HI (36.0 +/- 1.2 U/mg in naive hSOD1-Tg versus 29.1 +/- 1.7 U/mg in HI cortex and 29.2 +/- 2.0 for hypoxic cortex, p < 0.006). On the other hand, GPX activity in hGPX1-Tg after HI showed a significant increase by 24 h in the cortex ipsilateral to the injury (48.5 +/- 5.2 U/mg, compared with 37.2 +/- 1.5 U/mg in naive hGPX1-Tg cortex, p < 0.008). These findings support the hypothesis that the immature brain has limited GPX activity and is more susceptible to oxidative damage and may explain the paradoxical effect seen in ischemic neonatal brain when SOD1 is overexpressed.

Hip2Norm: an object-oriented cross-platform program for 3D analysis of hip joint morphology using 2D pelvic radiographs

We developed an object-oriented cross-platform program to perform three-dimensional (3D) analysis of hip joint morphology using two-dimensional (2D) anteroposterior (AP) pelvic radiographs. Landmarks extracted from 2D AP pelvic radiographs and optionally an additional lateral pelvic X-ray were combined with a cone beam projection model to reconstruct 3D hip joints. Since individual pelvic orientation can vary considerably, a method for standardizing pelvic orientation was implemented to determine the absolute tilt/rotation. The evaluation of anatomically morphologic differences was achieved by reconstructing the projected acetabular rim and the measured hip parameters as if obtained in a standardized neutral orientation. The program had been successfully used to interactively objectify acetabular version in hips with femoro-acetabular impingement or developmental dysplasia. Hip(2)Norm is written in object-oriented programming language C++ using cross-platform software Qt (TrollTech, Oslo, Norway) for graphical user interface (GUI) and is transportable to any platform.

An investigation of phenolic glycoside and condensed tannin homeostasis in Populus by salicyl alcohol feeding to cell cultures and by transgenic manipulation of the sucrose transporter, PTSUT4, in planta

Secondary metabolites play an important role in plant protection against biotic and abiotic stress. In Populus, phenolic glycosides (PGs) and condensed tannins (CTs) are two such groups of compounds derived from the common phenylpropanoid pathway. The basal levels and the inducibility of PGs and CTs depend on genetic as well as environmental factors, such as soil nitrogen (N) level. Carbohydrate allocation, transport and sink strength also affect PG and CT levels. A negative correlation between the levels of PGs and CTs was observed in several studies. However, the molecular mechanism underlying such relation is not known. We used a cell culture system to understand negative correlation of PGs and CTs. Under normal culture conditions, neither salicin nor higher-order PGs accumulated in cell cultures. Several factors, such as hormones, light, organelles and precursors were discussed in the context of aspen suspension cells’ inability to synthesize PGs. Salicin and its isomer, isosalicin, were detected in cell cultures fed with salicyl alcohol, salicylaldehyde and helicin. At higher levels (5 mM) of salicyl alcohol feeding, accumulation of salicins led to reduced CT production in the cells. Based on metabolic and gene expression data, the CT reduction in salicin-accumulating cells is partly a result of regulatory changes at the transcriptional level affecting carbon partitioning between growth processes, and phenylpropanoid CT biosynthesis. Based on molecular studies, the glycosyltransferases, GT1-2 and GT1-246, may function in glycosylation of simple phenolics, such as salicyl alcohol in cell cultures. The uptake of such glycosides into vacuole may be mediated to some extent by tonoplast localized multidrug-resistance associated protein transporters, PtMRP1 and PtMRP6. In Populus, sucrose is the common transported carbohydrate and its transport is possibly regulated by sucrose transporters (SUTs). SUTs are also capable of transporting simple PGs, such as salicin. Therefore, we characterized the SUT gene family in Populus and investigated, by transgenic analysis, the possible role of the most abundantly expressed member, PtSUT4, in PG-CT homeostasis using plants grown under varying nitrogen regimes. PtSUT4 transgenic plants were phenotypically similar to the wildtype plants except that the leaf area-to-stem volume ratio was higher for transgenic plants. In SUT4 transgenics, levels of non-structural carbohydrates, such as sucrose and starch, were altered in mature leaves. The levels of PGs and CTs were lower in green tissues of transgenic plants under N-replete, but were higher under N-depleted conditions, compared to the levels in wildtype plants. Based on our results, SUT4 partly regulates N-level dependent PG-CT homeostasis by differential carbohydrate allocation.