Demography of agile gibbons (Hylobates agilis)

Demographic processes and the structure of a population of agile gibbons (Hylobates agilis) were investigated over 6 years in the Gunung Palung Reserve, Indonesia. Estimates of population size, density, and biomass revealed a population whose groups were stable in size and composition. Demographic processes place gibbons at risk, however, to short-term changes in their environment. Patterns of survival, fecundity, mortality, and dispersal combined to produce negative rates of growth. In addition, a top-heavy age-class distribution, with adults forming a large fraction of animals, makes it unlikely that this population could recover rapidly from a decline in numbers. Two behavioral factors, territoriality and monogamy, account for the size and stability of gibbon groups. Monogamy imposes limits on group size, while mating patterns and territoriality decrease the impact of sources of high mortality common in other primate species. These relationships underscore the fundamental importance of behavioral influence on demographic processes and social structure.     

A procedure to produce gnotobiotic calves by cesarean section.

An effective and economical method was developed for procuring and rearing calves in gnotobiotic conditions. To evaluate apparatuses and surgical techniques, three calves, 1 to 3, welf 1 was weak and pale at delivery and died within 5 hours after delivery. Calf 2 was delivered alive, but died from a human error at 3 days of age. It was free from demonstrable bacteria and fungi at that time. Calf 3 was also successfully delivered and raised. It was killed at 10 days of age, since fungi were isolated from the feces and waste materials from it.     

Recognition of rat liver and kidney nuclear T3 receptors by an antibody against c-erb A peptide

It has been reported that c-erb A encodes nuclear T3 receptors (NT3R). Based on the sequence of c-erb A cDNA, we synthesized a polypeptide consisting of 15 amino acids, the sequence of which has high homology between c-erb A alpha 1 and beta. The antibody against this c-erb A peptide not only immunoprecipitated rat liver and kidney NT3R but also inhibited T3 binding to NT3R. In a displacement study, the inhibition of [125I]T3-binding by the antibody was parallel to that by T3 in terms of the concentration of the competitor added in the incubation mixture. Scatchard analysis revealed that the antibody decreased the value for the association constant in a dose dependent manner. The antibody did not bind T3 itself. The results show that the antibody against c-erb A peptide recognizes rat liver and kidney NT3R and that the sequence encoding this peptide, the closest carboxyl-terminal of c-erb A may be critical or at least closely related to the hormone binding.     

Mitochondria‐type GPAT is required for mitochondrial fusion

Glycerol‐3‐phosphate acyltransferase (GPAT) is involved in the first step in glycerolipid synthesis and is localized in both the endoplasmic reticulum (ER) and mitochondria. To clarify the functional differences between ER‐GPAT and mitochondrial (Mt)‐GPAT, we generated both GPAT mutants in C. elegans and demonstrated that Mt‐GPAT is essential for mitochondrial fusion. Mutation of Mt‐GPAT caused excessive mitochondrial fragmentation. The defect was rescued by injection of lysophosphatidic acid (LPA), a direct product of GPAT, and by inhibition of LPA acyltransferase, both of which lead to accumulation of LPA in the cells. Mitochondrial fragmentation in Mt‐GPAT mutants was also rescued by inhibition of mitochondrial fission protein DRP‐1 and by overexpression of mitochondrial fusion protein FZO‐1/mitofusin, suggesting that the fusion/fission balance is affected by Mt‐GPAT depletion. Mitochondrial fragmentation was also observed in Mt‐GPAT‐depleted HeLa cells. A mitochondrial fusion assay using HeLa cells revealed that Mt‐GPAT depletion impaired mitochondrial fusion process. We postulate from these results that LPA produced by Mt‐GPAT functions not only as a precursor for glycerolipid synthesis but also as an essential factor of mitochondrial fusion.     

Female parity, male aggression, and the Challenge Hypothesis in wild chimpanzees

The Challenge Hypothesis proposes that testosterone mediates aggression during periods of heightened conflict between males, especially episodes that have important fitness consequences. Considerable evidence from seasonally breeding species provides support for this hypothesis, but few data exist in animals that mate year-round. We tested predictions generated by the Challenge Hypothesis in chimpanzees, a non-seasonally breeding primate, through a study of individuals living in an exceptionally large community at Ngogo, Kibale National Park, Uganda. Results indicated that dominance rank had no influence on testosterone levels. Instead of rank influencing testosterone production, additional analyses revealed an important role for reproductive competition. Male chimpanzees displayed more aggression when they were in the same party as parous estrous females than when reproductively active females were unavailable. Male chimpanzees competed more intensely for mating opportunities with parous females than with nulliparas, and as a consequence, males displayed more aggression around the former than the latter. When males accompanied parous estrous females, their urinary testosterone concentrations were significantly higher than baseline concentrations. In contrast, urinary testosterone concentrations did not exceed baseline when males associated with nulliparous estrous females. These differences in testosterone levels could not be attributed to mating per se because males copulated equally often with parous and nulliparous females. Furthermore, variation in testosterone concentrations were not due to males gathering together in large parties, as their levels in these situations did not exceed baseline. Taken together, these findings, derived from a relatively large sample of males and estrous females, replicate those from a prior study and furnish additional support for the Challenge Hypothesis. Our results suggest that the Challenge Hypothesis is likely to be broadly applicable to chimpanzees and increase our understanding of the physiological costs to males who compete for estrous females.     

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.     

Incorporation of Glycine and Serine into Sporulating Cells of Bacillus subtilis

The changes during growth and sporulation in activities of cells of Bacillus subtilis to incorporate various amino acids were investigated with wild-type strain and its asporogenous mutant. In the case of wild type strain the uptake of valine, phenylalanine, and proline was largest during the logarithmic growth period. The uptake of these amino acids decreased rapidly during the early stationary phase. The uptake of valine and cysteine increased again to some extent just prior to the forespore stage. The uptake of glycine and serine, however, was largest at the forespore stage at which the formation of spore coat took place. From these observed phenomena it was assumed that the remarkable incorporation of glycine and serine into the wild type strain during sporulation was closely related to the formation of spore coat.     

Mutant analyses reveal different functions of fgfr1 in medaka and zebrafish despite conserved ligand-receptor relationships

Medaka (Oryzias latipes) is a small freshwater teleost that provides an excellent developmental genetic model complementary to zebrafish. Our recent mutagenesis screening using medaka identified headfish (hdf) which is characterized by the absence of trunk and tail structures with nearly normal head including the midbrain-hindbrain boundary (MHB). Positional-candidate cloning revealed that the hdf mutation causes a functionally null form of Fgfr1. The fgfr1hdf is thus the first fgf receptor mutant in fish. Although FGF signaling has been implicated in mesoderm induction, mesoderm is induced normally in the fgfr1hdf mutant, but subsequently, mutant embryos fail to maintain the mesoderm, leading to defects in mesoderm derivatives, especially in trunk and tail. Furthermore, we found that morpholino knockdown of medaka fgf8 resulted in a phenotype identical to the fgfr1hdf mutant, suggesting that like its mouse counterpart, Fgf8 is a major ligand for Fgfr1 in medaka early embryogenesis. Intriguingly, Fgf8 and Fgfr1 in zebrafish are also suggested to form a major ligand-receptor pair, but their function is much diverged, as the zebrafish fgfr1 morphant and zebrafish fgf8 mutant acerebellar (ace) only fail to develop the MHB, but develop nearly unaffected trunk and tail. These results provide evidence that teleost fish have evolved divergent functions of Fgf8-Fgfr1 while maintaining the ligand-receptor relationships. Comparative analysis using different fish is thus invaluable for shedding light on evolutionary diversification of gene function.     

The genetic signature of sex-biased migration in patrilocal chimpanzees and humans

A large body of theoretical work suggests that analyses of variation at the maternally inherited mitochondrial (mt)DNA and the paternally inherited non-recombining portion of the Y chromosome (NRY) are a potentially powerful way to reveal the differing migratory histories of men and women across human societies. However, the few empirical studies comparing mtDNA and NRY variation and known patterns of sex-biased migration have produced conflicting results. Here we review some methodological reasons for these inconsistencies, and take them into account to provide an unbiased characterization of mtDNA and NRY variation in chimpanzees, one of the few mammalian taxa where males routinely remain in and females typically disperse from their natal groups. We show that patterns of mtDNA and NRY variation are more strongly contrasting in patrilocal chimpanzees compared with patrilocal human societies. The chimpanzee data we present here thus provide a valuable comparative benchmark of the patterns of mtDNA and NRY variation to be expected in a society with extremely female-biased dispersal.     

Anterosuperior protraction of maxillae using the extraoral device,RAMPA; finite element method

Abstract

This paper presents a boosting effect against gravity by analyzing the displacement and stress distribution of craniofacial structures due to the protraction of the extraoral device, the Right Angle Maxillary Protraction Appliance(RAMPA) system, including semi-rapid maxillary expansion (sRME) using the finite element method. In addition, a patient case was illustrated and compared with the results calculated from a simulation. The results from the finite element method were obtained for 0.5?mm activation using the screw of the intraoral device, gHu-1. This study reveals that RAMPA rotates the patient’s maxilla and mandible in the forward direction and forces them to move forward and upward.