Birth of a Western Lowland gorilla (Gorilla gorilla gorilla) following in vitro fertilization and embryo transfer

A 21-year-old multiparous female exhibiting 31–41 day menstrual cycles was given hFSH (225 IU/day, Metrodin 75, from cycle day 3 through 9 (menses = day 1) and hCG (10,000 IU, Profasi, on day 10 to stimulate follicular development. At 35 h after hCG, under isoflurane (AErrane) anesthesia, follicles were aspirated by controlled suction under transvaginal ultrasound guidance. Metaphase II oocyctes (n = 11) were placed in modified human tubal fluid (mHTF, 100 μl) medium under oil at 37°C in humidified 5% CO₂. Frozen semen, collected by voluntary ejaculation, was thawed (70°C H₂O bath, 6 sec), diluted slowly, centrifuged, and resuspended in mHTF, and 160,000 motile spermatozoa/ml were added at 6 h after oocyte recovery. At 21 h postinsemination (p.i.) eight oocytes were at the two-cell stage, five were cryopreserved, and three were cultured to the six- to eight-cell stage in mHTF with granulosa cells before transcervical uterine transfer at 47 h p.i. using a Teflon catheter. Micronized progesterone (400 mg/d) was orally administered for 10 weeks posttransfer (p.t.). Ultrasound examination revealed a single fetus at 15 weeks p.t., and unassisted delivery of a live 1.37 kg female infant occurred at 29 weeks. Am. J. Primatol. 41:247–260, 1997. © 1997 Wiley-Liss, Inc.     

Breeding limits foraging time: evidence of interrupted foraging response from body mass variation in a tropical environment

Birds should store body reserves if starvation risk is anticipated; this is known as an ‘interrupted foraging response’. If foraging remains unrestricted, however, body mass should remain low to limit the predation risk that gaining and carrying body reserves entails. In temperate environments mass gain in female birds during breeding is often attributed to egg formation and mass loss after incubation to flight adaptation or the effect of reproductive workload, rather than as a result of an adaptive interrupted foraging response to the limited foraging time or unpredictable foraging conditions that breeding demands. In tropical environments, foraging conditions vary more within the breeding season than in temperate environments, and so studies in tropical environments are more suited to decouple the potentially confounded effects of increase in body reserves versus egg formation on the body mass of breeding birds. In this study, we test whether breeding results in an interrupted foraging response in a tropical savannah system using body mass data collected over a 15‐year period from female common bulbuls Pycnonotus barbatus. This species breeds both in the wet and dry season, despite fewer resources being available in the dry season. Breeding stage predicted female body mass: body mass peaked abruptly during incubation, but was not closely associated with the egg‐laying stage, and declined during brood rearing. Breeding females were heavier in the dry season than in the wet season. In the dry season, heavier birds were more likely to incubate eggs or brood chicks. These observations suggest that increased body reserves are required to buffer the consequence of limited foraging time or impoverished foraging conditions, which may be most pronounced during incubation and in the dry season, respectively. Such mass increases are consistent with an interrupted foraging response, which may apply to temperate zone birds experiencing foraging restrictions during breeding.     

Low and annually variable migratory connectivity in a long‐distance migrant: Whinchats Saxicola rubetra may show a bet‐hedging strategy

The spatial scale of non‐breeding areas used by long‐distance migrant animals can vary from specific, relatively small non‐breeding areas for each independent breeding population (high connectivity) to a distribution over a large non‐breeding area with mixing of breeding populations (low connectivity). Measuring variation in the degree of connectivity and how it arises is crucial to predict how migratory animals can respond to global habitat and climate change because low connectivity is likely to be an adaptation to environmental uncertainty. Here, we assess whether use of non‐breeding areas in a long‐distance migrant may be stochastic by measuring the degree of connectivity, and whether it is annually variable. Twenty‐nine wintering Whinchats tagged with geolocators over 2 years within 40 km² in central Nigeria were found to be breeding over 2.55 million km² (26% of the land area of Europe), without an asymptote being approached in the relationship between area and sample size. Ranges differed in size between years by 1.51 million km² and only 15% of the total breeding range across both years overlapped (8% overlap between years when only first‐year birds were considered), well above the range size difference and below the proportion of overlap that would be predicted from two equivalent groups breeding at random locations within the observed range. Mean distance between breeding locations (i.e. migratory spread) differed significantly between years (604 ± 18 km in 2013 and 869 ± 33 km in 2014). The results showed very low and variable connectivity that was reasonably robust to the errors and assumptions inherent in the use of geolocators, but with the caveat of having only ranges of 2 years to compare, and the sensitivity of range to the breeding locations of a small number of individuals. However, if representative, the results suggest the scope for between‐year variation (cohort effects) to determine migrant distribution on a large scale. Furthermore, for species with similarly low connectivity, we would predict breeding population trends to reflect average conditions across large non‐breeding areas: thus, as large areas of Africa become subject to habitat loss, migrant populations throughout Europe will decline.     

A novel constitutive model for passive right ventricular myocardium: evidence for myofiber–collagen fiber mechanical coupling

The function of right ventricle (RV) is recognized to play a key role in the development of many cardiopulmonary disorders, such as pulmonary arterial hypertension (PAH). Given the strong link between tissue structure and mechanical behavior, there remains a need for a myocardial constitutive model that accurately accounts for right ventricular myocardium architecture. Moreover, most available myocardial constitutive models approach myocardium at the length scale of mean fiber orientation and do not explicitly account for different fibrous constituents and possible interactions among them. In the present work, we developed a fiber-level constitutive model for the passive mechanical behavior of the right ventricular free wall (RVFW). The model explicitly separates the mechanical contributions of myofiber and collagen fiber ensembles, and accounts for the mechanical interactions between them. To obtain model parameters for the healthy passive RVFW, the model was informed by transmural orientation distribution measurements of myo- and collagen fibers and was fit to the mechanical testing data, where both sets of data were obtained from recent experimental studies on non-contractile, but viable, murine RVFW specimens. Results supported the hypothesis that in the low-strain regime, the behavior of the RVFW is governed by myofiber response alone, which does not demonstrate any coupling between different myofiber ensembles. At higher strains, the collagen fibers and their interactions with myofibers begin to gradually contribute and dominate the behavior as recruitment proceeds. Due to the use of viable myocardial tissue, the contribution of myofibers was significant at all strains with the predicted tensile modulus of \(\sim \)32 kPa. This was in contrast to earlier reports (Horowitz et al. 1988) where the contribution of myofibers was found to be insignificant. Also, we found that the interaction between myo- and collagen fibers was greatest under equibiaxial strain, with its contribution to the total stress not exceeding 20 %. The present model can be applied to organ-level computational models of right ventricular dysfunction for efficient diagnosis and evaluation of pulmonary hypertension disorder.     

Seasonal home range dynamics and sex differences in habitat use in a threatened,coastal marsh bird

A comprehensive understanding of spatiotemporal ecology is needed to develop conservation strategies for declining species. The king rail (Rallus elegans) is a secretive marsh bird whose range historically extended across the eastern United States. Inland migratory populations have been greatly reduced with most remaining populations inhabiting the coastal margins. Our objectives were to determine the migratory status of breeding king rails on the mid‐Atlantic coast and to characterize home range size, seasonal patterns of movement, and habitat use. Using radiotelemetry, we tracked individual king rails among seasons, and established that at least a segment of this breeding population is resident. Mean (±SE) home range size was 19.8 ± 5.0 ha (95% kernel density) or 2.5 ± 0.9 (50% kernel density). We detected seasonal variation and sex differences in home range size and habitat use. In the nonbreeding season, resident male home ranges coincided essentially with their breeding territories. Overwintering males were more likely than females to be found in natural emergent marsh with a greater area of open water. Females tended to have larger home ranges than males during the nonbreeding season. We report for the first time the use of wooded natural marsh by overwintering females. Brood‐rearing king rails led their young considerable distances away from their nests (average maximum distance: ~600 ± 200 m) and used both wooded natural and impounded marsh. King rails moved between natural marsh and managed impoundments during all life stages, but the proximity of these habitat types particularly benefitted brood‐rearing parents seeking foraging areas with shallower water in proximity to cover. Our results demonstrate the importance of interspersion of habitat types to support resident breeders. Summer draining of impounded wetlands that are seasonally flooded for wintering waterfowl allows regrowth of vegetation and provides additional habitat at a critical time for wading birds.     

Suppression of viral specific primary T-cell response following intense physical exercise in young but not old mice.

Intense exercise to exhaustion leads to increased susceptibility and severity of infections. T cells play an essential role in control of viral infections. Whereas immune suppression is considered as a likely mechanism for exhaustive exercise-induced susceptibility to infection, we know little about viral-specific T-cell response following exhaustive exercise in young or old mice. In this study, one group of female young (10-12 wk) and old (22-24 mo) C57BL/6 mice was exposed to a single bout of intense exercise to exhaustion and immediately infected with lymphocytic choriomeningitis virus (LCMV). Eight days later, at the peak of expansion phase of T-cell response, we used tetramers of MHC class I molecules containing viral peptides to directly visualize antigen-specific CD8 T cells and a sensitive functional assay measuring interferon-gamma production at the single-cell level to quantitate the CD8 and CD4 T-cell response. To evaluate the impact of intense exercise during both the initiation and evolution of the expansion phase of the T-cell response, a second group of young and old mice continued their daily bouts of intense exercise to exhaustion over the next 8 days. Our data show that, in young mice, LCMV infection following exhaustive exercise leads to suppression of LCMV-specific CD8 and CD4 T-cell responses, and this suppression effect occurs at the initiation of the expansion phase of viral-specific T cells. However, in old mice, unlike young mice, exhaustive exercise does not cause suppression of LCMV-specific T-cell responses.     

Serological evidence of typhus group rickettsia in a homeless population in Houston, Texas

We tested sera from 176 homeless people in Houston for antibodies against typhus group rickettsiae (TGR). Sera from 19 homeless people were reactive to TGR antigens by ELISA and IFA. Two people had antibodies against Rickettsia prowazekii (epidemic typhus) and the remaining 17 had antibodies against Rickettsia typhi (murine typhus).     

End-functionalized phosphorylcholine methacrylates and their use in protein conjugation

Polymer-protein conjugation was performed using N-hydroxysuccinimide and aldehyde-terminated zwitterionic polymers, and the resulting polymer-protein conjugates were characterized by gel electrophoresis and fast protein liquid chromatography. Methacryloyloxyethyl phosphorylcholine (MPC) polymers were prepared by atom transfer radical polymerization in which the requisite functional end-groups for protein conjugation were embedded within the polymerization initiators. These phosphorylcholine polymers were conjugated to lysozyme as a model protein, as well as two therapeutic proteins, granulocyte colony stimulating factor (G-CSF) and erythropoietin (EPO). These MPC polymer-protein conjugates represent alternatives to PEGylated proteins, with the potential to provide improved efficacy in a therapeutic treatment relative to the protein itself.     

Variations in stress sensitivity and genomic expression in diverse S. cerevisiae isolates

Interactions between an organism and its environment can significantly influence phenotypic evolution. A first step toward understanding this process is to characterize phenotypic diversity within and between populations. We explored the phenotypic variation in stress sensitivity and genomic expression in a large panel of Saccharomyces strains collected from diverse environments. We measured the sensitivity of 52 strains to 14 environmental conditions, compared genomic expression in 18 strains, and identified gene copy-number variations in six of these isolates. Our results demonstrate a large degree of phenotypic variation in stress sensitivity and gene expression. Analysis of these datasets reveals relationships between strains from similar niches, suggests common and unique features of yeast habitats, and implicates genes whose variable expression is linked to stress resistance. Using a simple metric to suggest cases of selection, we found that strains collected from oak exudates are phenotypically more similar than expected based on their genetic diversity, while sake and vineyard isolates display more diverse phenotypes than expected under a neutral model. We also show that the laboratory strain S288c is phenotypically distinct from all of the other strains studied here, in terms of stress sensitivity, gene expression, Ty copy number, mitochondrial content, and gene-dosage control. These results highlight the value of understanding the genetic basis of phenotypic variation and raise caution about using laboratory strains for comparative genomics.