Sexual behaviour of group-living adolescent chimpanzees

This paper reports a study of the heterosexual behavior of three male and four female captive adolescent chimpanzees living a semi-natural life style in a large field enclosure. Observations made with binoculars from an over-head deck were balanced over the daylight hours and the seven weekdays. We recorded 213 copulations in 741.25 hours of observation between February 14 and July 21, 1972. Analysis of the observations suggests that group-living chimpanzees in a large field enclosure behave more like free-living chimpanzees than like other captive chimpanzees paired in small cages. In this group, copulations were non-randomly distributed throughout the day, a finding in agreement with results on wild-living chimpanzees but not previously reported for captive chimpanzees. In this group, moreover, copulations were highly concentrated within each female's period of maximum tumescence, as are those of free-living chimpanzees; and individual differences in sexual attractiveness among females were apparently based on a maturational threshold of swelling size, a phenomenon that has also been reported for wild chimpanzees.     

An Artificial “gum-tree” for marmosets (Callithrix j. jacchus)

Marmosets (Callithrix, Cebuella) in the wild gouge wells in trees and eat the exudates that accumulate there. An artificial gum-tree was made of wooden dowel and filled with Acacia Senegal exudate (gum arabic) dissolved in water. Three families of marmosets avidly gouged and consumed gum from this device, showing all of the behavioral patterns described in nature. The gum-tree cost little and was easy to make.     

CSE1 and CSE2, two new genes required for accurate mitotic chromosome segregation in Saccharomyces cerevisiae.

By monitoring the mitotic transmission of a marked chromosome bearing a defective centromere, we have identified conditional alleles of two genes involved in chromosome segregation (cse). Mutations in CSE1 and CSE2 have a greater effect on the segregation of chromosomes carrying mutant centromeres than on the segregation of chromosomes with wild-type centromeres. In addition, the cse mutations cause predominantly nondisjunction rather than loss events but do not cause a detectable increase in mitotic recombination. At the restrictive temperature, cse1 and cse2 mutants accumulate large-budded cells, with a significant fraction exhibiting aberrant binucleate morphologies. We cloned the CSE1 and CSE2 genes by complementation of the cold-sensitive phenotypes. Physical and genetic mapping data indicate that CSE1 is linked to HAP2 on the left arm of chromosome VII and CSE2 is adjacent to PRP2 on chromosome XIV. CSE1 is essential and encodes a novel 109-kDa protein. CSE2 encodes a 17-kDa protein with a putative basic-region leucine zipper motif. Disruption of CSE2 causes chromosome missegregation, conditional lethality, and slow growth at the permissive temperature.     

Gap junction structures: Analysis of the x-ray diffraction data

Models for the spatial distribution of protein, lipid and water in gap junction structures have been constructed from the results of the analysis of X-ray diffraction data described here and the electron microscope and chemical data presented in the preceding paper (Caspar, D. L. D., D. A. Goodenough, L. Makowski, and W.C. Phillips. 1977. 74:605-628). The continuous intensity distribution on the meridian of the X-ray diffraction pattern was measured, and corrected for the effects of the partially ordered stacking and partial orientation of the junctions in the X-ray specimens. The electron density distribution in the direction perpendicular to the plane of the junction was calculated from the meridional intensity data. Determination of the interference function for the stacking of the junctions improved the accuracy of the electron density profile. The pair-correlation function, which provides information about the packing of junctions in the specimen, was calculated from the interference function. The intensities of the hexagonal lattice reflections on the equator of the X-ray pattern were used in coordination with the electron microscope data to calculate to the two-dimensional electron density projection onto the plane of the membrane. Differences in the structure of the connexons as seen in the meridional profile and equatorial projections were shown to be correlated to changes in lattice constant. The parts of the junction structure which are variable have been distinguished from the invariant parts by comparison of the X-ray data from different specimens. The combination of these results with electron microscope and chemical data provides low resolution three- dimensional representations of the structures of gap junctions.     

A Novel Piggybac Transposon Inducible Expression System Identifies a Role for Akt Signalling in Primordial Germ Cell Migration

In this work, we describe a single piggyBac transposon system containing both a tet-activator and a doxycycline-inducible expression cassette. We demonstrate that a gene product can be conditionally expressed from the integrated transposon and a second gene can be simultaneously targeted by a short hairpin RNA contained within the transposon, both in vivo and in mammalian and avian cell lines. We applied this system to stably modify chicken primordial germ cell (PGC) lines in vitro and induce a reporter gene at specific developmental stages after injection of the transposon-modified germ cells into chicken embryos. We used this vector to express a constitutively-active AKT molecule during PGC migration to the forming gonad. We found that PGC migration was retarded and cells could not colonise the forming gonad. Correct levels of AKT activation are thus essential for germ cell migration during early embryonic development.     

Ranging behavior of Mahale chimpanzees: a 16 year study

We have analyzed the ranging patterns of the Mimikire group (M group) of chimpanzees in the Mahale Mountains National Park, Tanzania. During 16 years, the chimpanzees moved over a total area of 25.2 or 27.4 km², as estimated by the grid-cell or minimum convex polygon (MCP) methods, respectively. Annually, the M group used an average of 18.4 km², or approximately 70 %, of the total home-range area. The chimpanzees had used 80 % of their total home range after 5 years and 95 % after 11 years. M group chimpanzees were observed more than half of the time in areas that composed only 15 % of their total home range. Thus, they typically moved over limited areas, visiting other parts of their range only occasionally. On average, the chimpanzees used 7.6 km² (in MCP) per month. Mean monthly range size was smallest at the end of the rainy season and largest at the end of the dry season, but there was much variability from year to year. The chimpanzees used many of the same areas every year when Saba comorensis fruits were abundant between August and January. In contrast, the chimpanzees used several different areas of their range in June. Here range overlap between years was relatively small. Over the 16 years of the study we found that the M group reduced their use of the northern part of their range and increased their frequency of visits to the eastern mountainous side of their home range. Changes in home-range size correlated positively with the number of adult females but not with the number of adult males. This finding does not support a prediction of the male-defended territory model proposed for some East African chimpanzee unit-groups.     

Community composition, correlations among taxa, prevalence, and richness in gastrointestinal parasites of baboons in Senegal, West Africa

Studies of gastrointestinal parasite prevalence in Papio have either focused on a single troop or compared prevalence among troops that share migrants but differ in degree of human contact. Little is known about the extent of variation in prevalence where obvious factors that may drive prevalence (e.g., human contact) are absent, so it is difficult to interpret variation when these factors are present. To address this issue, we studied troops of Guinea baboons (Papio papio) that had almost no contact with humans or domesticated species of plants or animals. We tested the null hypotheses that community composition, richness, and prevalence would be similar between groups in two comparisons: (1) between troops in the same locality with no known differences in drivers of prevalence, and (2) between samples at the same location taken more than 20 years apart. We collected anonymous fecal samples from two troops of baboons living in a wilderness site, Mt. Assirik, in the Niokolo-Koba National Park, Republic of Senegal, West Africa. We collected samples from two valleys and analyzed prevalence and richness with respect to place and time. Both prevalence and richness were similar in the two valleys, but significant changes emerged in both prevalence and community composition compared with the previous survey in 1978–1979. We also found that the nematode Enterobius and a fluke, Watsonius, co-occurred within hosts more frequently than expected. This phenomenon has not been previously noted in the literature, and it suggests common environmental drivers or facilitation among these parasites.     

Edmonston measles virus prevents increased cell surface expression of peptide-loaded major histocompatibility complex class II proteins in human peripheral monocytes

Gamma interferon (IFN-gamma) induces expression of the gene products of the major histocompatibility complex (MHC), whereas IFN-alpha/beta can interfere with or suppress class II protein expression. In separate studies, measles virus (MV) was reported to induce IFN-alpha/beta and to up-regulate MHC class II proteins. In an attempt to resolve this paradox, we examined the surface expression of MHC class I and class II proteins in MV-infected peripheral monocytes in the presence and absence of IFN-alpha/beta. Infection of purified monocytes with Edmonston B MV resulted in an apparent increase in cell surface expression of HLA-A, -B, and -C class I proteins, but it had no effect on the expression of HLA-DR class II proteins. MV-infected purified monocytes expressed IFN-alpha/beta, but no measurable IFN-gamma expression was detected in supernatant fluids. Class II protein expression could be enhanced by coculture of purified monocytes with uninfected peripheral blood mononuclear cell (PBMC) supernatant. MV infection of PBMCs also did not affect expression of class II proteins, but the expression of HLA-A, -B, and -C class I proteins was increased two- to threefold in most donor cells. A direct role for IFN-alpha/beta suppression of MHC class II protein expression was not evident in monocytes since MV suppressed class II protein expression in the absence of IFN-alpha/beta. Taken together, these data suggest that MV interferes with the expression of peptide-loaded class II complexes, an effect that may potentially alter CD4(+)-T-cell proliferation and the cell-mediated immune responses that they help to regulate.