Seasonal change in the composition of the diet of eastern lowland gorillas

Details are presented of the composition of the diet of eastern lowland gorillas, derived mainly from a study of their fresh trails and fecal analysis, during the course of an entire year in the tropical lowland forests of the Itebero region, Zaire. Gorillas ate 194 plant foods from 121 species and 45 families. They consumed 48 species of fruits; and 89% of fecal samples contained fruit seeds, but fruits were a relatively small part (25%) of the total number of food items. The composition of their diet changed seasonally. When consumption of fruit decreased in the long rainy and the long dry seasons, the gorillas ate, in addition to Zingiberaceae and Marantaceae, many kinds of leaf and bark, which may be an important buffer against the shortage of fruits. Gorillas also fed regularly on ants (Ponerinae), and the frequency of consumption showed small seasonal variations. From a comparison of diet composition, eastern lowland gorillas appeared to be intermediate between the other two subspecies. The choice of food showed differences in preference of fruits and insects between subspecies and may reflect high similarities within subspecies in lowland and montane forests.     

Genotyping from semen of wild Japanese macaques (Macaca fuscata)

The noninvasive collection of animal cells is crucial for DNA analyses in wild populations that cannot be disturbed by capture. We describe the collection of 68 semen samples following copulation and masturbation events in wild habituated and nonhabituated troops of Japanese macaques on the protected island of Yakushima. We used this DNA to amplify 390 base pairs (bp) of the mitochondrial DNA control region in 16 individuals from eight troops, and found a monomorphic pattern in agreement with the low variability imposed by geographic isolation and female philopatry. We also amplified two microsatellite loci from samples collected after the resident males of a focal troop had copulated with different females. We found several different allele combinations in samples collected after the observed mating of a single male, indicating the presence of contaminant DNA, presumably from males that had previously mated with the same female. This discovery made it impossible to assign a given sample to a specific male except when the samples were recovered after masturbation events. Thus, it was not possible to test for kinship or estimate allele frequencies from the semen samples. The mixing of semen, and the pattern of sample collection observed in morphologically identified individuals support the notion that strong mating and sperm competition exists among resident and nonresident males.     

How fruit abundance affects the chimpanzee party size: a comparison between four study sites

We examined the relationship between fruit abundance and chimpanzee (Pan troglodytes) party size by comparing data from four study sites: the Kalinzu Forest Reserve, Uganda, the Djinji Camp and Guga Camp in the Ndoki Forest, Congo, and Kahuzi-Biega National Park, Democratic Republic of Congo. Although the difference in the fruit abundance between the sites was responsible for the difference in the party size between the sites, the seasonal changes in fruit abundance did not explain the changes in the party size in each study site. Across the four study sites, there were significant correlations of the mean and minimum of monthly party size with the mean of monthly fruiting-tree density, and a significant correlation of the maximum of monthly party sizes with the minimum of monthly fruiting-tree density. We proposed a hypothesis that (1) the monthly fruit abundance affects the monthly party size in the sites where the fruit availability is as low as to limit the party size during a major part of a year, while (2) the party size does not increase with the increase in the monthly fruit abundance, but is affected by other social factors, in the sites where the minimum of monthly fruit abundance is high enough for chimpanzees to form parties of an adequate size. Electronic Publication     

Parasporin-2Ab,a Newly Isolated Cytotoxic Crystal Protein from <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis>

A novel crystal protein that exhibited potent cytotoxicity against human leukemic T-cells was cloned from the Bacillus thuringiensis TK-E6 strain. The protein, designated as parasporin-2Ab (PS2Ab), was a polypeptide of 304 amino acid residues with a predicted molecular weight of 33,017. The deduced amino acid sequence of PS2Ab showed significant homology (84% identitiy) to parasporin-2Aa (PS2Aa) from the B. thuringiensis A1547 strain. Upon processing of PS2Ab with proteinase K, the active form of 29 kDa was produced. The activated PS2Ab showed potent cytotoxicity against MOLT-4 and Jurkat cells and the EC₅₀ values were estimated as 0.545 and 0.745 ng/mL, respectively. The cytotoxicity of PS2Ab was significantly higher than that of PS2Aa reported elsewhere. Although both cytotoxins were structurally related, it was thought that the minor differences found were responsible for the different cytotoxicities of PS2Ab and PS2Aa.     

Species and sex identification of western lowland gorillas (Gorilla gorilla gorilla), eastern lowland gorillas (Gorilla beringei graueri) and humans

Methods for the identification of the sex and species of individuals from samples non-invasively taken from humans and gorillas were established. Amplification of a segment of amelogenin (AMG), which is an X–Y homologous gene, using two pairs of primers from human AMG, revealed both X- and Y-specific bands. The possibility of sex identification was examined by typing the AMG gene using hair and fecal samples from captive western lowland gorillas (Gorilla gorilla gorilla) in Japan and hair samples from wild eastern lowland gorillas (Gorilla beringei graueri) in the Kahuzi-Biega National Park, Democratic Republic of Congo, which were sexed by direct observation. Species-specific bands of AMG in gorillas and humans were identified by restriction fragment length polymorphisms analysis. These tests could be used for sexing unidentified individuals of wild western and eastern lowland gorillas, and screening contamination of human DNA from non-invasively acquired samples.