2,763 research outputs found
Subclinical infection of macaques and baboons with a baboon simarterivirus
Simarteriviruses (Arteriviridae: Simarterivirinae) are commonly found at high titers in the blood of African monkeys but do not cause overt disease in these hosts. In contrast, simarteriviruses cause severe disease in Asian macaques upon accidental or experimental transmission. Here, we sought to better understand the host-dependent drivers of simarterivirus pathogenesis by infecting olive baboons (n = 4) and rhesus monkeys (n = 4) with the simarterivirus Southwest baboon virus 1 (SWBV-1). Surprisingly, none of the animals in our study showed signs of disease following SWBV-1 inoculation. Three animals (two rhesus monkeys and one olive baboon) became infected and sustained high levels of SWBV-1 viremia for the duration of the study. The course of SWBV-1 infection was highly predictable: plasma viremia peaked between 1 × 107 and 1 × 108 vRNA copies/mL at 3–10 days post-inoculation, which was followed by a relative nadir and then establishment of a stable set-point between 1 × 106 and 1 × 107 vRNA copies/mL for the remainder of the study (56 days). We characterized cellular and antibody responses to SWBV-1 infection in these animals, demonstrating that macaques and baboons mount similar responses to SWBV-1 infection, yet these responses are ineffective at clearing SWBV-1 infection. SWBV-1 sequencing revealed the accumulation of non-synonymous mutations in a region of the genome that corresponds to an immunodominant epitope in the simarterivirus major envelope glycoprotein GP5, which likely contribute to viral persistence by enabling escape from host antibodies
Anatomy of Soft Tissues of the Spinal Canal
Background and Objectives.
Important issues regarding the spread of solutions in the epidural space and the anatomy of the site of action of spinal and epidural injections are unresolved. However, the detailed anatomy of the spinal canal has been incompletely determined. We therefore examined the microscopic anatomy of the spinal canal soft tissues, including relationships to the canal walls.
Methods.
Whole mounts were prepared of decalcified vertebral columns with undisturbed contents from three adult humans. Similar material was prepared from a macaque and baboon immediately on death to control for artifact of tissue change after death. Other tissues examined included nerve root and proximal spinal nerve complex and dorsal epidural fat obtained during surgery. Slides were examined by light microscopy at magnifications of 10-40×.
Results.
There is no fibrous tissue in the epidural space. The epidural fat is composed of uniform cells enclosed in a fine membrane. The dorsal fat is only attached to the canal wall in the dorsal midline and is often tenuously attached to the dura. The dura is joined to the canal wall only ventrally at the discs. Veins are evident predominantly in the ventral epidural space. Nerve roots are composed of multiple fascicles which disperse as they approach the dorsal root ganglion. An envelope of arachnoid encloses the roots near the site of exit from the dura.
Conclusions.
These features of the fat explain its semifluid consistency. Lack of substantial attachments to the dura facilitate movement of the dura relative to the canal wall and allow distribution of injected solution. Fibrous barriers are an unlikely explanation for asymmetric epidural anesthesia, but the midline fat could impede solution spread. Details of nerve-root structure and their envelope of pia-arachnoid membrane may be relevant to anesthetic action
Infection of a yellow baboon with simian immunodeficiency virus from African green monkeys:evidence for cross-species transmission in the wild
Many African primates are known to be naturally infected with simian immunodeficiency viruses (SIVs), but only a fraction of these viruses has been molecularly characterized. One primate species for which only serological evidence of SIV infection has been reported is the yellow baboon (Papio hamadryas cynocephalus). Two wild-living baboons with strong SIVAGM seroreactivity were previously identified in a Tanzanian national park where baboons and African green monkeys shared the same habitat (T. Kodama, D. P. Silva, M. D. Daniel, J. E. Phillips-Conroy, C. J. Jolly, J. Rogers, and R. C. Desrosiers, AIDS Res. Hum. Retroviruses 5:337-343, 1989). To determine the genetic identity of the viruses infecting these animals, we used PCR to examine SIV sequences directly in uncultured leukocyte DNA. Targeting two different, nonoverlapping genomic regions, we amplified and sequenced a 673-bp gag gene fragment and a 908-bp env gene fragment from one of the two baboons. Phylo-genetic analyses revealed that this baboon was infected with an SIVAGM strain of the vervet subtype. These results provide the first direct evidence for simian-to-simian cross-species transmission of SIV in the wild
Do red deer stags (Cervus elaphus) use roar fundamental frequency (F0) to assess rivals?
It is well established that in humans, male voices are disproportionately lower pitched than female voices, and recent studies suggest that this dimorphism in fundamental frequency (F0) results from both intrasexual (male competition) and intersexual (female mate choice) selection for lower pitched voices in men. However, comparative investigations indicate that sexual dimorphism in F0 is not universal in terrestrial mammals. In the highly polygynous and sexually dimorphic Scottish red deer Cervus elaphus scoticus, more successful males give sexually-selected calls (roars) with higher minimum F0s, suggesting that high, rather than low F0s advertise quality in this subspecies. While playback experiments demonstrated that oestrous females prefer higher pitched roars, the potential role of roar F0 in male competition remains untested. Here we examined the response of rutting red deer stags to playbacks of re-synthesized male roars with different median F0s. Our results show that stags’ responses (latencies and durations of attention, vocal and approach responses) were not affected by the F0 of the roar. This suggests that intrasexual selection is unlikely to strongly influence the evolution of roar F0 in Scottish red deer stags, and illustrates how the F0 of terrestrial mammal vocal sexual signals may be subject to different selection pressures across species. Further investigations on species characterized by different F0 profiles are needed to provide a comparative background for evolutionary interpretations of sex differences in mammalian vocalizations
Effects of Instrumentation on Dental Microwear Textures: Reanalysis and Augmentation of an Early Hominin Sample
Dental microwear texture analysis has been refined to a methodology relying upon scanning confocal microscopy for its advantages of repeatability and standardized quantification. A new instrument, the Plu Neox (Sensofar Corp.) confocal profiler recently entered the market, sparking questions among dental anthropologists related to the advantages and efficacy of this new technology, which has better resolution and lighting properties than previously available white-lighted based confocal profilers. This thesis reports on three complementary studies that set out to evaluate the comparability of the Plu Neox to the Plu Standard system and assess its ability to distinguish primates on the basis of their microwear patterning. The first study examines a sample of hominin molars (Australopithecus africanus and Paranthropus robustus) for comparison with data previously scanned and analyzed on the University of Arkansas\u27 Plu Standard confocal microscope (Scott et al., 2005). The second study expands the sample of early hominins to determine whether an enlarged sample of A. africanus continues to show significant texture separation from P. robustus. And the third study examines extant primate microwear textures of pitheciids with known dietary differences to determine whether documented food-choice trends are reflected in microwear patterning obtained using the Plu Neox. Examining pitheciine molar facets in the past was not possible because of their small size. The new instrument provides higher resolution (0.11 um with a 150x objective compared to 0.18 um at 100x on the Plu Standard confocal), with a smaller work envelop for a comparable number of sampled points for texture analysis. Results of the first study generally correspond to the original texture analysis of 2005, and the expanded dataset in the second study shows increased variance but the same pattern of differences for A. africanus compared with P. robustus. The third study finds that the Plu Neox is capable of parsing broad diet-related differences in microwear textures among the pitheciids, indicating that the new instrument may become an effective instrument for the quantitative characterization and comparison of dental microwear textures to be utilized in laboratories around the world
Differential resistance to cell entry by porcine endogenous retrovirus subgroup A in rodent species
Background: The risk of zoonotic infection by porcine endogenous retroviruses (PERV) has been highlighted in the context of pig-to-human xenotransplantation. The use of receptors for cell entry often determines the host range of retroviruses. A human-tropic PERV subgroup, PERV-A, can enter human cells through either of two homologous multitransmembrane proteins, huPAR-1 and huPAR-2. Here, we characterised human PARs and their homologues in the PERV-A resistant rodent species, mouse and rat ( muPAR and ratPAR, respectively).
Results: Upon exogenous expression in PERV-A resistant cells, human and rat PARs, but not muPAR, conferred PERV-A sensitivity. Exogenously expressed ratPAR binds PERV-A Env and allows PERV-A infection with equivalent efficiency to that of huPAR-1. Endogenous ratPAR expression in rat cell lines appeared to be too low for PERV-A infection. In contrast, the presence of Pro at position 109 in muPAR was identified to be the determinant for PERV-A resistance. Pro109. was shown to be located in the second extracellular loop (ECL2) and affected PERV-A Env binding to PAR molecules.
Conclusion: The basis of resistance to PERV-A infection in two rodent species is different. Identification of a single a. a. mutation in muPAR, which is responsible for mouse cell resistance to PERV-A highlighted the importance of ECL-2 for the viral receptor function
Signal Reconstruction via H-infinity Sampled-Data Control Theory: Beyond the Shannon Paradigm
This paper presents a new method for signal reconstruction by leveraging
sampled-data control theory. We formulate the signal reconstruction problem in
terms of an analog performance optimization problem using a stable
discrete-time filter. The proposed H-infinity performance criterion naturally
takes intersample behavior into account, reflecting the energy distributions of
the signal. We present methods for computing optimal solutions which are
guaranteed to be stable and causal. Detailed comparisons to alternative methods
are provided. We discuss some applications in sound and image reconstruction
Pseudotyped Lentiviral Vectors: One Vector, Many Guises
Viruses have evolved specialized molecular mechanisms to transfer their genome efficiently into host cells. Viruses can be repurposed into viral vectors to achieve controlled gene transfer to desired cells. One of the most popular class of vectors, lentiviral vectors, transduce mammalian cells efficiently. Lentiviral vectors are pseudotyped with various heterologous viral envelopes to alter their tropism. While the most common example is the envelope glycoprotein from vesicular stomatitis virus (VSVG), many other viral proteins have also been used. Pseudotyping lentiviral vectors with a diverse set of naturally occurring or engineered viral envelopes has allowed targeted infection of specific cell types. Many exciting studies are further uncovering new specificities and shortcomings of pseudotyped lentiviral vectors. These studies will expand the toolbox to make lentiviral vectors that cater to the specific requirements of transduction. In this review, we provide a comprehensive overview of various viral envelope pseudotypes used with LVs, their specificity, advantages, and drawbacks
Supervised Classification of Baboon Vocalizations
International audienceThis paper addresses automatic classification of baboon vocalizations. We considered six classes of sounds emitted by "Papio papio" baboons, and report the results of supervised classification carried out with different signal representations (audio features), classifiers, combinations and settings. Results show that up to 94.1\% of correct recognition of pre-segmented elementary segments of vocalizations can be obtained using Mel-Frequency Cepstral Coefficients representation and Support Vector Machines classifiers. Results for other configurations are also presented and discussed, and a possible extension to the "Sound-spotting'' problem, i.e. online joint detection and classification of a vocalization from a continuous audio stream is illustrated and discussed
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