Chimpanzee (Pan troglodytes) birth patterns and human presence in zoological settings

In response to work demonstrating a negative correlation between human staff activity and parturition in laboratory-managed primates, this study examined the distribution of 231 captive chimpanzee (Pan troglodytes) births that occurred in accredited American zoological institutions by the day of the week on which the birth was discovered. We hypothesized that if chimpanzee parturition patterns displayed sensitivity to human presence, then fewer births per day would be reported during the weekend period, when the visitor density was high, as compared with the lower density working week. Analyses indicated that chimpanzee births were randomly distributed throughout the week. In the context of the questionable sensitivity of primate parturition to external influence, results suggest that variations in human presence do not affect the fine-level timing of birth in chimpanzees managed in a zoological setting.     

Studying reactive processes with classical dynamics: rebinding dynamics in MbNO

A new surface-crossing algorithm suitable for describing bond-breaking and bond-forming processes in molecular dynamics simulations is presented. The method is formulated for two intersecting potential energy manifolds which dissociate to different adiabatic states. During simulations, crossings are detected by monitoring an energy criterion. If fulfilled, the two manifolds are mixed over a finite number of time steps, after which the system is propagated on the second adiabat and the crossing is carried out with probability one. The algorithm is extensively tested (almost 0.5 mus of total simulation time) for the rebinding of NO to myoglobin. The unbound surface (Fe...NO) is represented using a standard force field, whereas the bound surface (Fe-NO) is described by an ab initio potential energy surface. The rebinding is found to be nonexponential in time, in agreement with experimental studies, and can be described using two time constants. Depending on the asymptotic energy separation between the manifolds, the short rebinding timescale is between 1 and 9 ps, whereas the longer timescale is about an order of magnitude larger. NO molecules which do not rebind within 1 ns are typically found in the Xenon-4 pocket, indicating the high affinity of NO to this region in the protein.     

Parturition in horses is dominated by parasympathetic activity of the autonomous nervous system

External and internal stressors prolong parturition in different species. At parturition, sympathoadrenal activation should be avoided because an increased sympathetic tone may cause uterine atonia via β₂-receptors. We hypothesized that at physiological parturition, horses are under parasympathetic dominance, and stress-response mechanisms are not activated during delivery of the foal. To evaluate stress responses, heart rate, heart rate variability, catecholamines, and cortisol were analyzed in mares (n = 17) throughout foaling. Heart rate decreased from 2 hours before (51 ± 1 beats/minute) to 2 hours after delivery (41 ± 2 beats/minute; P < 0.05). Heart rate variability variables, standard deviation of the beat-to-beat interval, and root mean square of successive beat-to-beat differences, changed over time (P < 0.05) with the highest values within 15 minutes after delivery. The number of mares with atrioventricular blocks and the number of atrioventricular blocks per mare increased over time (P < 0.01) and were significantly elevated from 15 minutes before to 45 minutes after birth of the foal. Salivary cortisol concentrations increased to a maximum at 30 minutes after delivery (25.0 ± 3.4 ng/mL; P < 0.01). Plasma epinephrine and norepinephrine concentrations showed significant fluctuations from rupture of the allantochorion to expulsion of the fetal membranes (P < 0.01) but were not markedly elevated at any time. In conclusion, mares give birth under high parasympathetic tone. Cortisol release during and after foaling is most likely part of the endocrine pathways regulating parturition and not a labor-associated stress response.     

Parturition in the camel (Camelus dromedarius) and some behavioral aspects of their newborn

Symptoms of approaching parturition and the stage of parturition were described for eight pluriparous camels. The average time for the complete process of parturition was 373.9 +/- 38.2 min. The body weights at birth of the newborn males and females were 31.3 +/- 1.69 and 24.5 +/- 2.5 kg, respectively. Standing and first suckling by the neonatal camels occurred at 68.6 +/- 6.2 and 98.6 +/- 11.3 min, respectively.     

Placental transfer of cholesterol-4-14C into rabbit and guinea pig fetus

A tracer dose of cholesterol-4-(14)C was given daily in the diet of six pregnant guinea pigs to establish an isotopic steady state. At the time of parturition, maternal and fetal blood and fetal tissues were collected and analyzed for cholesterol content and cholesterol specific activity. A comparison of these specific activities in neonatal and maternal serum indicated that about 22% of the fetal serum cholesterol was transferred from maternal blood. In the newborn, tissues generally had the same cholesterol specific activity as serum. Brain tissue was an exception in having a specific activity only 8.4% of that of serum. Dietary cholesterol did not increase serum cholesterol levels in the newborn but did increase the percentage of fetal cholesterol derived from the maternal circulation. The rapid transfer of cholesterol-4-(14)C across the placenta was indicated by the appearance of this isotope in the newborn 2 days after its administration to pregnant rabbits. A considerable amount of the cholesterol content of newborn guinea pigs and rabbits originated from the maternal blood.     

Temperature's influence on the activity budget,terrestriality, and sun exposure of chimpanzees in the Budongo Forest,Uganda

Chimpanzee (Pan troglodytes schweinfurthii) activity budget, terrestriality, and sun exposure were found to be influenced by the immediate environmental temperature. Thirty adult chimpanzees in the Budongo Forest, Uganda, were observed for 247 h. Temperatures in the shade and sun, sky cover, sun exposure, activity, and terrestriality were recorded at 5‐min intervals at <15 m from the center of the party. Terrestriality frequency was 26.5% for females and 41.5% for males. Terrestriality and resting both show a significant positive correlation with temperature in the sun. Controlling for seven potential confounding factors, temperature in the sun remained the strongest predictor of terrestriality. The difference between temperatures in the sun and shade had a significant effect on chimpanzee sun exposure frequency. Time spent continuously in the sun was negatively correlated with temperature, beginning to decrease around 30°C, and markedly decreasing around 40°C. A concurrent experiment determined that dark pelage (lacking physiological coping mechanisms) exposed to the same solar regime can easily reach 60°C within minutes. This study indicates that both temperature in the sun and sun exposure play a role in influencing chimpanzee activity behavior, and specifically suggests that chimpanzees thermoregulate behaviorally both by moving to the ground and by decreasing their activity level. These results, in the context of deforestation and increasing global temperatures, have physiological and conservation implications for wild chimpanzees. Am J Phys Anthropol, 2009. © 2008 Wiley‐Liss, Inc.     

Free radicals, lipid peroxidation and the antioxidant system in the blood of cows and newborn calves around calving

The oxidative stress of birth in cattle (Bos taurus) was evaluated by measuring steady state concentration of free radicals in whole blood, rate of lipid peroxidation and activity of antioxidant enzymes in erythrocytes, antioxidant capacity of blood plasma in 14 calves at birth and four times after birth until 3 weeks of age and also in their mothers at calving. The same parameters were also measured in 58 dairy cows before calving, at parturition and after calving. Free radical concentration in the blood of newborn calves was higher than in cows confirming that birth means oxidative stress for calves. Red blood cell malondialdehyde in calves was the highest at birth and following the first solid feed intake at the third week. Superoxide dismutase activity increased in calves during the first three weeks of life. Ferric reducing ability of plasma was higher in calves at birth than in cows and decreased thereafter. Higher superoxide dismutase activity in red blood cells and lower ferric reducing ability of plasma in dairy cows was found at calving compared to the average of all pre- and post-calving results. We conclude that the blood of newborn calves is well prepared to deal with the oxidative stress of birth, and that such a stress is present even when some fingerprint markers of redox imbalance show no apparent alterations. Stress of calving has minor effects on the antioxidant system of cows.     

Rhesus macaque class I duplicon structures, organization, and evolution within the alpha block of the major histocompatibility complex

The alpha block of the human and chimpanzee major histocompatibility complex (MHC) class I genomic region contains 10 to 11 duplicated MHC class I genes, including the HLA/Patr-A, -G, and -F genes. In comparison, the alpha block of the rhesus macaque (Macaca mulatta, Mamu) has an additional 20 MHC class I genes within this orthologous region. The present study describes the identification and analysis of the duplicated segmental genomic structures (duplicons) and genomic markers within the alpha block of the rhesus macaque and their use to reconstruct the duplication history of the genes within this region. A variety of MHC class I genes, pseudogenes, transposons, and retrotransposons, such as Alu and ERV16, were used to categorize the 28 duplicons into four distinct structural categories. The phylogenetic relationship of MHC class I genes, Alu, and LTR16B sequences within the duplicons was examined by use of the Neighbor-Joining (NJ) method. Two single-duplicon tandem duplications, two polyduplicon tandem duplications with an accompanying inversion product per duplication, eight polyduplicon tandem duplications steps, 12 deletions, and at least two recombinations were reconstructed to explain the highly complex organization and evolution of the 28 duplicons (nine inversions) within the Mamu alpha block. On the basis of the phylogenetic evidence and the reconstructed tandem duplication history of the 28 duplicons, the Mamu/Patr/HLA-F ortholog was the first MHC class I gene to have been fixed without further duplication within the alpha block of primates. Assuming that the rhesus macaque and the chimpanzee/human lineages had started with the same number of MHC class I duplicons at the time of their divergence approximately 24 to 31 MYA, then the number of genes within the alpha block have been duplicated at an approximately three times greater rate in the rhesus macaque than in either the human or chimpanzee.     

Effect of photoperiod, injection of pentobarbitone sodium or lesion of the suprachiasmatic nucleus on pre-partum decrease of blood progesterone concentrations or time of birth in the rat

In Sprague-Dawley rats kept under 14L:10D (lights on 05:00-19:00 h), parturition occurred during the light phase on Day 23, and the pre-partum decrease in progesterone concentrations was observed between 07:00 and 15:00 h during the light period on Day 22. When the rats were transferred to reversed light-dark regimen (lights on 17:00-07:00 h) on Day 7, the progesterone decrease and parturition still occurred during the light period on Day 21 and 22-23, respectively. However, when rats were kept in constant darkness from Day 7, parturition occurred independently of the time of day between Day 22 and 24. A gradual decline of progesterone concentrations was randomly observed in individual rats. In Wistar rats kept under the usual light-dark regimen, parturitions were biphasic, occurring during the light periods on Day 22 and 23. The progesterone decrease occurred at the usual time even when the lighting regimen was changed only on the day of the expected progesterone decrease. However, treatment with pentobarbitone sodium at 15:00, 19:00 or 21:00 h, but not at 12:00 or 23:00 h, on Day 21 resulted in a delay of progesterone decrease and of parturition. Complete lesion of the suprachiasmatic nucleus on Day 13 or 14 led to advancement and random distribution of the time of birth. These results suggest that the time of parturition and of pre-partum progesterone decrease may be closely associated with an endogenous circadian system, and a luteolytic factor involving the nervous system may be present during a limited period before parturition.     

Effectiveness of a redesigned vaginal implant transmitter in mule deer

Our understanding of factors that limit mule deer (Odocoileus hemionus) populations may be improved by evaluating neonatal survival as a function of dam characteristics under free-ranging conditions, which generally requires that both neonates and dams are radiocollared. The most viable technique facilitating capture of neonates from radiocollared adult females is use of vaginal implant transmitters (VITs). To date, VITs have allowed research opportunities that were not previously possible; however, VITs are often expelled from adult females prepartum, which limits their effectiveness. We redesigned an existing VIT manufactured by Advanced Telemetry Systems (ATS; Isanti, MN) by lengthening and widening wings used to retain the VIT in an adult female. Our objective was to increase VIT retention rates and thereby increase the likelihood of locating birth sites and newborn fawns. We placed the newly designed VITs in 59 adult female mule deer and evaluated the probability of retention to parturition and the probability of detecting newborn fawns. We also developed an equation for determining VIT sample size necessary to achieve a specified sample size of neonates. The probability of a VIT being retained until parturition was 0.766 (SE = 0.0605) and the probability of a VIT being retained to within 3 days of parturition was 0.894 (SE = 0.0441). In a similar study using the original VIT wings (Bishop et al. 2007 ), the probability of a VIT being retained until parturition was 0.447 (SE = 0.0468) and the probability of retention to within 3 days of parturition was 0.623 (SE = 0.0456). Thus, our design modification increased VIT retention to parturition by 0.319 (SE = 0.0765) and VIT retention to within 3 days of parturition by 0.271 (SE = 0.0634). Considering dams that retained VITs to within 3 days of parturition, the probability of detecting at least 1 neonate was 0.952 (SE = 0.0334) and the probability of detecting both fawns from twin litters was 0.588 (SE = 0.0827). We expended approximately 12 person-hours per detected neonate. As a guide for researchers planning future studies, we found that VIT sample size should approximately equal the targeted neonate sample size. Our study expands opportunities for conducting research that links adult female attributes to productivity and offspring survival in mule deer. © 2011 The Wildlife Society.     

Birth upregulates nitric oxide synthase activity in the porcine lung

Developmental changes in the lung occur at birth, allowing for the transition from placental to air breathing. Here we have measured nitric oxide synthase (NOS) activity in the porcine lung pre and post partum. NOS activity, which was predominantly calcium dependent, was low in full term fetal tissue compared to that present in lungs from the newborn (5 minutes post partum), 1, 3, 6 and 14 day old animals. No increase in activity was seen when fetal pigs were allowed to breathe for 5 minutes. Specific activity remained low in fetal tissue following partial purification. By contrast, levels of NOS III protein in tissue extracts and in pulmonary arterial endothelial cells, demonstrated by immunohistochemistry, were similar in tissue from the fetal and newborn animals. Thus NOS activity is significantly lower in fetal when compared to postnatal lung tissue despite comparable amounts of NOS III protein being expressed, and birth is followed by an abrupt increase in enzyme activity in animals born at term which correlates with an increase in protein expression.     

Natural transmission of Cryptosporidium parvum between dams and calves on a dairy farm

The transmission of Cryptosporidium parvum between dams and their respective calves was studied. For this purpose, fecal specimens taken from the rectum of preparturient, parturient, and postparturient dams were analyzed for C. parvum oocysts. Fecal specimens were taken from the newborn calf 4 hr after birth. Because the environment can be a source of contamination to the animals, specimens taken from inside and outside the barn were analyzed. The sucrose concentration method together with the Zielh-Nielsen acid-fast staining method were employed to increase the chances of oocyst detection. We are reporting that at parturition, the dams shed a higher number of oocysts by comparison to the preparturient and postparturient periods. Neonates acquire the infection at birth mainly because of the high number of oocysts shed by the dams at parturition. The management practice of moving calves 4 hr after birth away from the dams and the barn reduces the number of clinical cases because they are no longer in contact with an environment that is highly contaminated. We hypothesize that the increase in the number of oocysts sheds by dams at parturition might be due to a depression of the T helper 1-type of immune response during that period.     

Factors from fluid of the ovarian pocket that stimulate sperm motility in domestic hens.

Fluid was collected from the region of the peritoneum surrounding the ovarian pocket of domestic hens at about the time of ovulation. This fluid, diluted to 10%, increased the motility of chicken spermatozoa by a maximum of sixfold at 40 degrees C in vitro. Gel filtration revealed two peaks of motility-stimulating activity: one was identified as calcium and the other as a heat-labile substance of low M(r) (200). It is suggested that this motility-stimulating activity may facilitate fertilization, as spermatozoa are normally stored in a quiescent state within the oviduct and can be passively transported by cilia to the site of fertilization in the ovarian pocket.     

Presbytis entellus: Birth in a free-ranging primate troop

During a 20-month study of two troops ofP. entellus in a village habitat in West Bengal one of seven births was observed. The female came down to the ground 21 minutes prior to parturition and returned to the trees 19 minutes later. She was accompanied by two adult females; there was no adult male present in the troop. The amount of time spent on the ground was significantly greater than expected for that time of year.     

Causal knowledge of predators' behaviour in wild Diana monkeys

Wild Diana monkeys, Cercopithecus diana, of Ta? forest, Ivory Coast, are preyed upon by leopards, Panthera pardus, and chimpanzees, Pan troglodytes. These two predators differ in their main hunting tactic and Diana monkeys attempt to avoid predation with two distinct antipredator strategies: conspicuous alarm-calling behaviour to leopards and silent, cryptic behaviour to chimpanzees. However, the Diana monkeys' choice of the appropriate antipredator strategy is complicated by the fact that chimpanzees themselves also fall prey to leopards. Chimpanzees give loud and conspicuous alarm screams when they detect a leopard. When these chimpanzees' leopard alarm calls were played back to different groups of Diana monkeys, in about half of the cases recipients switched from a chimp-specific cryptic response to a leopard-specific conspicuous response, suggesting that some individuals assumed the presence of a leopard. Groups whose home range was in the core area of the resident chimpanzee community were more likely to respond this way than more peripheral groups, indicating between-group differences in semantic knowledge. In a follow-up experiment, the monkeys' understanding of the chimpanzee alarm calls was further assessed with a prime-probe technique. Monkeys were primed with chimpanzee alarm calls and then, 5 min later, tested with leopard growls to see whether they were able to anticipate the presence of a leopard. Results were consistent with the hypothesis that monkeys responding cryptically to chimpanzee alarm calls did so because they were not able to understand the calls' meaning. Data are discussed with respect to three possible cognitive mechanisms, associative learning, specialized learning programmes, and causal reasoning, that could have led to causal knowledge in some individuals but not others. Copyright 2000 The Association for the Study of Animal Behaviour.     

Analysis of the third transmembrane domain of the human type 1 angiotensin II receptor by cysteine scanning mutagenesis

Activation of G protein-coupled receptors by agonists involves significant movement of transmembrane domains (TMD) following agonist binding. The underlying structural mechanism by which receptor activation takes place is largely unknown but can be inferred by detecting variability within the environment of the ligand-binding pocket, which is a water-accessible crevice surrounded by the seven TMD helices. Using the substituted-cysteine accessibility method, we identified the residues within the third TMD of the wild-type angiotensin II (AT1) receptor that contribute to the formation of the binding site pocket. Each residue within the Ile103-Tyr127 region was mutated one at a time to a cysteine. Treating the A104C, N111C, and L112C mutant receptors with the charged sulfhydryl-specific alkylating agent methanethiosulfonate-ethylammonium (MTSEA) strongly inhibited ligand binding, which suggests that these residues orient themselves within the water-accessible binding pocket of the AT1 receptor. Interestingly, this pattern of acquired MTSEA sensitivity was altered for TMD3 reporter cysteines engineered in a constitutively active AT1 receptor. Indeed, two additional mutants (S109C and V116C) were found to be sensitive to MTSEA treatment. Our results suggest that constitutive activation of the AT1 receptor causes a minor counterclockwise rotation of TMD3, thereby exposing residues, which are not present in the inactive state, to the binding pocket. This pattern of accessibility of residues in the TMD3 of the AT1 receptor parallels that of homologous residues in rhodopsin. This study identified key elements of TMD3 that contribute to the activation of class A G protein-coupled receptors through structural rearrangements.     

Canine fetal heart rate: Do accelerations or decelerations predict the parturition day in bitches?

Ultrasonography is a safe and efficient technique for monitoring fetal development and viability. One of the most important and widely used parameters to verify fetal viability is the fetal heart rate (HR). In human medicine, the fetal HR normally oscillates during labor in transient accelerations and decelerations associated with uterine contractions. The present study investigated whether these variations also occur in canine fetuses and its relationship to parturition. A cohort study was conducted in 15 pregnant bitches undergoing two-dimensional high-resolution ultrasonographic examination during the 8th and 9th week of gestation. Fetal HR was assessed in M-mode for 5 minutes in each fetus in all bitches. In addition, the bitches were monitored for clinical signs of imminent parturition. Associations between the HR, antepartum time, and delivery characteristics were evaluated with a Poisson regression model. Fetal HR acceleration and deceleration occurred in canine fetuses and predicted the optimal time of parturition. These findings can help veterinarians and sonographers better understand this phenomenon in canine fetuses.