Concealing facial evidence of mood: Perspective-taking in a captive gorilla?

A captive female lowland gorilla was observed repeatedly to hide or inhibit her playface by placing one or both hands over the face. When this behaviour was seen play usually did not follow immediately, even if other signals associated with play were simultaneously being made by the gorilla. By contrast, a playface predicted that play would follow within a few seconds; this difference was statistically reliable. Several levels of interpretation of the behaviour are possible: hiding the playface may have functioned as a form of deception, a meta-communication, or merely an attempt to suppress the playface. However, by any of these interpretations, the behaviour implies that the gorilla is aware of her spontaneous facial expressions and the consequences they entail. Among the great apes, manual suppression of a facial expression has previously been reported once for chimpanzees but never for gorillas.     

Ecological Constraints on the Foraging Effort of Western Gorillas (Gorilla gorilla gorilla) at Bai Hoköu, Central African Republic

Recent studies demonstrate that western lowland gorillas incorporate much more fruit into their diet than Virunga mountain gorillas do. Very little is known, however, about how the frugivorous behavior of western gorillas influences their daily ranging behavior, which may ultimately affect social factors such as group size and structure. I examined the influence of diet and the spatiotemporal availability of plant foods on the foraging effort of nonhabituated western lowland gorilla groups during 17 months at Bai Hoköu in the Dzanga-Ndoki National Park, Central African Republic. I determined diet from indirect methods and gorilla plant food availability and spatial distribution from phenology and line transects. Daily path length gives an estimate of foraging effort and was the distance paced, following fresh gorilla trails, from morning to evening nest sites. The availability and distribution of fruit and its consumption by gorillas varied seasonally. When concentrating on fruits, gorillas traveled significantly farther (mean = 3.1 km/day) than when their diet consisted mostly of nonfruit vegetation, such as leaves and woody pith, stems, and bark (mean = 2.1 km/day). The amount of herbaceous vegetation in the diet did not vary seasonally and did not influence daily path length. The best environmental predictor of foraging effort was fruit density, or a measure combining both density and spatial pattern: coefficient of dispersion. In addition, when fruit patches were small, path length tended to increase but not significantly. Compared with results of other studies, gorillas at Bai Hoköu travel farther (mean = 2.6 km/day) than gorillas in Gabon (mean = 1.7 km/day) and five times farther than mountain gorillas in the Virungas (mean = 0.5 km/day). Increased foraging effort of gorillas in this region, especially during the fruiting season, may have profound effects on group size and structure.     

Sequence analysis of a variety of primate fertilin α genes: Evidence for non-functional genes in the gorilla and man

The sperm surface fertilin complex was first described in the guinea pig where it was found as a heterodimer of α and β subunits, both of which were proposed to play a role in sperm-oolemma recognition and plasma membrane fusion during fertilisation. Whilst the β subunit is apparently testis-specific, the finding of low levels of fertilin α in nonreproductive tissues has cast some doubt on a unique role in fertilisation. Moreover, the absence of a functional fertilin α gene in the human would imply that this gene product is not absolutely essential for fertilisation, although it could play a facilitatory role. We now describe the organisation and sequence of the fertilin α genes in a range of primates, including the great apes, and find that the gorilla gene, like that of the human, is non-functional. Mol. Reprod. Dev. 51:92–97, 1998. © 1998 Wiley-Liss, Inc.     

Western lowland gorilla density and nesting behavior in a Gabonese forest logged for 25 years: implications for gorilla conservation

The tropical forests of the Congo Basin constitute biodiversity refuges that still hold large numbers of species, including endemic and endangered vertebrates. Along with several key species, the critically endangered western lowland gorilla (WLG) potentially contributes to forest dynamics through seed dispersal. Considering the extensive influence of timber harvesting on tropical forest ecosystems, the survival of gorilla populations in logged forests might prove critical for forest ecosystem conservation. We estimated WLG density, through a nest count survey, in a forest in southeast Gabon that has been logged for 25 years. Nesting behavior and habitat use were described and we applied generalized linear models to identify the factors that influence gorilla day and night habitat use. The estimated density of weaned gorillas, 1.5 gorillas km^?2, is comparable with estimates from some protected areas and other sustainably managed sites within their range. Habitat type had the greatest influence on nest site distribution. We observed a preference for nesting in open terra firma forest, and open habitats in general, which supports the findings of previous studies. Habitat use during the day was strongly influenced by habitat type and human activities, and to a lesser degree by functional and non-functional roads, and rivers. Our results support the suggestion that logged forests are suitable habitats for WLG if hunting and poaching are controlled. We recommend collaborations between timber operators and scientists to improve the conservation potential of tropical forests and enhance the wildlife-management aspects of logging practices.     

Evolution of the primate β-Globin gene region: Nucleotide sequence of the δ-β-globin Intergenic region of gorilla and phylogenetic relationships between African Apes and Man

Summary A 6.0-kb DNA fragment from Gorilla gorilla including the 5 part of the -globin gene and about 4.5 kb of its upstream flanking region was cloned and sequenced. The sequence was compared to the human, chimpanzee, and macaque - intergenic region. This analysis reveals four tandemly repeated sequences (RS), at the same location in the four species, showing a variable number of repeats generating both intraspecific (polymorphism) and interspecific variability. These tandem arrays delimit five regions of unique sequence called IG for intergenic. The divergence for these IG sequences is 1.85 ± 0.22% between human and gorilla, which is not significantly different from the value estimated in the same region between chimpanzee and human (1.62 ± 0.21%). The CpG and TpA dinucleotides are avoided. CpGs evolve faster than other sequence sites but do not confuse phylogenetic inferences by producing parallel mutations in different lineages. About 75% of CpG doublets have become TpG or CpA since the common ancestor, in agreement with the methylation/deamination pattern. Comparison of this intergenic region gives information on branching order within Hominoidea. Parsimony and distance-based methods when applied to the - intergenic region provide evidence (although not statistically significant) that human and chimpanzee are more closely related to each other than to gorilla. CpG sites are indeed rich in information by carrying substitutions along the short internal branch. Combining these results with those on the — intergenic region, shows in a statistically significant way that chimpanzee is the closest relative of human. Offprint requests to: P. Perrin-Pecontal     

Behavioural Ecology and Group Cohesion of Juvenile Western Lowland Gorillas (Gorilla g. gorilla) during Rehabilitation in the Batéké Plateaux National Park,Gabon

Rehabilitation of animals followed by reintroduction into the wild can benefit conservation by supplementing depleted wild populations or reintroducing a species in an area where it has been extirpated or become extinct. The western lowland gorilla (WLG, Gorilla g. gorilla) is persistently poached; infants are often illegally traded and used as pets. Some are confiscated and rehabilitated, then kept in sanctuaries or reintroduced into the wild. Prior to reintroduction, the ability of the orphans to survive independently in their environment needs to be assessed. Here, we performed a multivariate analysis, including diet composition, activity-budget, and pattern of strata using of a group of five juvenile WLG in the process of rehabilitation and distinguished three sub-periods of ecological significance: the high furgivory period, the Dialium fruits consumption period, and the high folivory period. The consequences of these variations on their well-being (play behaviour) and the group cohesion (spatial proximity and social interactions) were examined. Like wild WLGs, diets shifted seasonally from frugivorous to folivorous, while the same staple foods were consumed and large amounts of Dialium fruits were seasonally gathered high in trees. When succulent fruit intake was the highest, thus providing high energy from sugar, juveniles spent less time feeding, more time playing and group cohesion was the highest. Conversely, the cohesion decreased with increasing folivory, individuals spent more time feeding and less time playing together. Nonetheless, the group cohesion also decreased after the death of one highly social, wild-born orphan. This may underscore the importance of skilled individuals in the cohesion and well-being of the entire group and, ultimately, to rehabilitation success. This study evaluates the rehabilitation success with regards to the methods used and highlights the need to consider a set of individual and environmental factors for enhancing rehabilitation while preserving the local biodiversity and individual well-being.     

Infant‐Directed Communication in Lowland Gorillas (Gorilla gorilla): Do Older Animals Scaffold Communicative Competence in Infants?

Infant-directed speech is a linguistic phenomenon in which adults adapt their language when addressing infants in order to provide them with more salient linguistic information and aid them in language acquisition. Adult-directed language differs from infant-directed language in various aspects, including speech acoustics, syntax, and semantics. The existence of a "gestural motherese" in interaction with infants, demonstrates that not only spoken language but also nonvocal modes of communication can become adapted when infants are recipients. Rhesus macaques are so far the only nonhuman primates where a similar phenomenon to "motherese" has been discovered: the acoustic spectrum of a particular vocalization of adult females may be altered when the addressees are infants. The present paper describes how gorillas adjust their communicative strategies when directing intentional, nonvocal play signals at infants in the sense of a "nonvocal motherese." Animals of ages above infancy use a higher rate of repetitions and sequences of the tactile sensory modality when negotiating play with infants. This indicates that gorillas employ a strategy of infant-specific communication.     

Human type I hair keratin pseudogene ϕ hHaA has functional orthologs in the chimpanzee and gorilla: evidence for recent inactivation of the human gene after the Pan-Homo divergence

In addition to nine functional genes, the human type I hair keratin gene cluster contains a pseudogene, phihHaA (KRTHAP1), which is thought to have been inactivated by a single base-pair substitution that introduced a premature TGA termination codon into exon 4. Large-scale genotyping of human, chimpanzee, and gorilla DNAs revealed the homozygous presence of the phihHaA nonsense mutation in humans of different ethnic backgrounds, but its absence in the functional orthologous chimpanzee (cHaA) and gorilla (gHaA) genes. Expression analyses of the encoded cHaA and gHaA hair keratins served to highlight dramatic differences between the hair keratin phenotypes of contemporary humans and the great apes. The relative numbers of synonymous and non-synonymous substitutions in the phihHaA and cHaA genes, as inferred by using the gHaA gene as an outgroup, suggest that the human hHaA gene was inactivated only recently, viz., less than 240,000 years ago. This implies that the hair keratin phenotype of hominids prior to this date, and after the Pan-Homo divergence some 5.5 million years ago, could have been identical to that of the great apes. In addition, the homozygous presence of the phihHaA exon 4 nonsense mutation in some of the earliest branching lineages among extant human populations lends strong support to the "single African origin" hypothesis of modern humans.     

Behavioural responses to photographs by pictorially naïve baboons (Papio anubis), gorillas (Gorilla gorilla) and chimpanzees (Pan troglodytes)

This study assessed how pictorially naïve nonhuman primates understand pictures. Fifty-five baboons with no prior exposure to pictures were trained to grasp a slice of banana presented against a pebble in a two alternative forced choice task. Post-training testing involved three stimulus pairs: (1) real banana slice vs. its picture, (2) the banana picture vs. a real pebble and (3) banana picture vs. a pebble picture which were presented twice. Preliminary data were also collected on naïve gorillas (n = 4) and chimpanzees (n = 7) using the same procedure. Baboons revealed a preference for the food picture in (2) and (3) and often ate this stimulus, but the food item and its picture were accurately discriminated in (1). These results suggest that baboons mistook the pictorial stimulus and its referent, but processed the banana pictures as poor exemplars of the real banana category. Among apes, only gorillas ate the banana pictures, suggesting that picture–object confusion may also occur in this species. Findings are discussed as pertaining to the general issue of representational abilities in nonhuman primates, and its evolution.     

Anaerobic Fungi in Gorilla (<Emphasis Type="Italic">Gorilla gorilla gorilla</Emphasis>) Feces: an Adaptation to a High-Fiber Diet?

Many studies have demonstrated the importance of symbiotic microbial communities for the host with beneficial effects for nutrition, development, and the immune system. The majority of these studies have focused on bacteria residing in the gastrointestinal tract, while the fungal community has often been neglected. Gut anaerobic fungi of the class Neocallimastigomycetes are a vital part of the intestinal microbiome in many herbivorous animals and their exceptional abilities to degrade indigestible plant material means that they contribute significantly to fermentative processes in the enteric tract. Gorillas rely on a highly fibrous diet and depend on fermentative microorganisms to meet their daily energetic demands. To assess whether Neocallimastigomycetes occur in gorillas we analyzed 12 fecal samples from wild Western lowland gorillas (Gorilla gorilla gorilla) from Dzanga–Sangha Protected Areas, Central African Republic, and subjected potential anaerobic fungi sequences to phylogenetic analysis. The clone library contained ITS1 fragments that we related to 45 different fungi clones. Of these, 12 gastrointestinal fungi in gorillas are related to anaerobic fungi and our phylogenetic analyses support their assignment to the class Neocallimastigomycetes. As anaerobic fungi play a pivotal role in plant fiber degradation in the herbivore gut, gorillas might benefit from harboring these particular fungi with regard to their nutritional status. Future studies should investigate whether Neocallimastigomycetes are also found in other nonhuman primates with high fiber intake, which would also benefit from having such highly efficient fermentative microbes.     

A comparative analysis of karyotypes of three species of Macleaya—producers of a complex of isoquinoline alkaloids

Using a set of methods (C-banding, DAPI-staining, fluorescence hybridization in situ (FISH) with probes of 26S and 5S rDNA, and analysis of meiosis), the first comparative cytogenetic study of three species of Macleaya, producers of complex isoquinoline alkaloids, cordate Macleaya cordata (Willd.) R. Br. (2n = 20), small-fruited Macleaya microcarpa (Maxim.) Fedde (2n = 20) and Macleaya kewensis Turrill (2n = 20), was first carried out. On the basis of morphometric analysis, formulas of karyotypes were made for each species. Species ideograms for M. cordata, M. microcarpa, and M. kewensis were constructed taking into account the polymorphic variants of the C-banding patterns and indicating the location of 26S and 5S rDNA sites. A comparative study revealed that the karyotypes of M. microcarpa and M. kewensis have more in common with each other than with M. cordata. Analysis of meiotic chromosomes suggests of genetic stability of Macleaya genomes. The results of chromosome analysis were used to confirm the close relationship of Macleaya and to clarify their phylogenetic relationships.     

Selection of optimal variants of Gō-like models of proteins through studies of stretching

The Gō-like models of proteins are constructed based on the knowledge of the native conformation. However, there are many possible choices of a Hamiltonian for which the ground state coincides with the native state. Here, we propose to use experimental data on protein stretching to determine what choices are most adequate physically. This criterion is motivated by the fact that stretching processes usually start with the native structure, in the vicinity of which the Gō-like models should work the best. Our selection procedure is applied to 62 different versions of the Gō model and is based on 28 proteins. We consider different potentials, contact maps, local stiffness energies, and energy scales—uniform and nonuniform. In the latter case, the strength of the nonuniformity was governed either by specificity or by properties related to positioning of the side groups. Among them is the simplest variant: uniform couplings with no i, i + 2 contacts. This choice also leads to good folding properties in most cases. We elucidate relationship between the local stiffness described by a potential which involves local chirality and the one which involves dihedral and bond angles. The latter stiffness improves folding but there is little difference between them when it comes to stretching.     

Effect of γ-Irradiation on Development of Lachrymator of Onion

A thermosensitive uracil requiring mutant of Bacillus subtilis Marburg 168 thy trp₂ ts42 was examined as to the colony forming ability at the permissive and nonpermissive temperatures. The viability of the mutant cells decreased rapidly at the restrictive temperature in the modified Woese’s (MW) medium. However, the cells retained viability when sodium succinate or potassium chloride was added to the medium at that temperature although uracil deficiency was unchanged. A little but significant incorporation of adenine-8-¹⁴C into RNA still continued even after the incorporation of N-acetyl-³H-d-glucosamine into acid insoluble fraction of the cells terminated in the MW medium at 48°C. Both incorporations as well as increase of absorbance were slowed down in the presence of sodium succinate at 48°C. This mutant, ts42, was more sensitive to deoxycholate (DOC) than the parent strain. The restoration of colony forming ability after the temperature shift back from 48 to 37°C was suppressed by the addition of DOC to the medium. However, the cell became resistant to DOC when uracil was added to the medium prior to the temperature shift.     

Mechanisms of action of the α-amylase of Micromonospora melanosporea

The -amylase of Micromonospora melanosporea was produced extracellularly during batch fermentation in a 5.0-1 fermentor. The absence of an organic nitrogen source in its growth medium facilitated subsequent purification of the enzyme by ammonium sulphate fractionation and two consecutive Superose-12 gel-filtration steps. The enzyme exhibited maxima for activity at pH 7.0 and 55° C and was 72% stable at pH 6.0–12.0 for 30 min at 40° C. It had a relative molecular mass of 45 000 and an isoelectric point at pH 7.6. The enzyme catalyses the conversion of starch to maltose (53%, w/w) as the predominant final end-product. Initial hydrolysis of this substrate, however, gave rise to the formation of maltooligosaccharides in the range maltotriose to maltohexaose. Maximum yields of these intermediate sugars accumulated to between 31 and 42% (w/w) as the reaction proceeded. The action of the M. melanosporea amylase on high concentrations of saccharides larger than maltotriose resulted in the formation of mainly maltose and maltotriose without concomitant glucose production. A combination of hydrolytic and transfer events is postulated to be responsible for this phenomenon and for the high maltose levels achieved. Correspondence to: C. T. Kelly     

Chemistry of the “molecular trap” of protease-catalyzed splicing reaction of complementary segments of α-subunit of hemoglobin A

The complementary fragments of human Hb α, α_1–30, and α_31–141 are spliced together by V8 protease in the presence of 30%n-propanol to generate the full-length molecule (Hb α-semisynthetic reaction). Unlike the other protease-catalyzed protein/peptide splicing reactions of fragment complementing systems, the enzymic condensation of nonassociating segments of Hb α is facilitated by the organic cosolvent induced α-helical conformation of product acting as the “molecular trap” of the splicing reaction. The segments α_24–30 and α_31–40 are the shortest complementary segments that can be spliced by V8 protease. In the present study, the chemistry of the contiguous segment (product) α_24–40 has been manipulated by engineering the amino acid replacements to the positions α²⁷ and α³¹ to delineate the structural basis of the molecular trap. The location of Glu²⁷ and Arg³¹ residues in the contiguous segment α_24–40 (as well as in other larger segments) is ideal to generate (i, i+4) side-chain carboxylate-guanidino interaction in its α-helical conformation. The amino acid residue replacement studies have confirmed that the side chains at α²⁷ and α³¹ facilitate the semisynthetic reaction. The relative influence of the substitute at these sites on the splicing reaction depends on the chemical nature of the side chain and the location. The γ-carboxylate guanidino side-chain interaction appears to contribute up to a maximum of 85% of the thermodynamic stability of the molecular trap. The studies also demonstrate that the thermodynamic stability of the molecular trap is determined by two interdependent conformational aspects of the peptide. One is an amino acid-sequence-specific event that facilitates the induction of an α-helical conformation to the contiguous segment in the presence of organic cosolvent that imparts some amount of protease resistance to Glu³⁰-Arg³¹ peptide bond. The second structural aspect is a site-specific event, ani, i+4 side-chain interaction in the α-helical conformation of the peptide which imparts an additional thermodynamic stability to the molecular trap. The results suggest that conformationally driven “molecular traps” of protease-mediated ligation reactions of peptides could be designed into products to facilitate the modular assembly of peptides/proteins.     

Association of the subunits of the calcium-independent receptor of α-latrotoxin

CIRL-1 also called latrophilin 1 or CL belongs to the family of adhesion G protein-coupled receptors (GPCRs). As all members of adhesion GPSR family CIRL-1 consists of two heterologous subunits, extracellular hydrophilic p120 and heptahelical membrane protein p85. Both CIRL-1 subunits are encoded by one gene but as a result of intracellular proteolysis of precursor, mature receptor has two-subunit structure. It was also shown that a minor portion of the CIRL-1 receptor complexes dissociates, producing the soluble receptor ectodomain, and this dissociation is due to the second cleavage at the site between the site of primary proteolysis and the first transmembrane domain. Recently model of independent localization p120 and p85 on the cell surface was proposed. In this article we evaluated the amount of p120-p85 complex still presented on the cellular membrane and confirmed that on cell surface major amount of mature CIRL-1 presented as a p120-p85 subunit complex.     

Kinetics of renaturation and self-assembly of intermediates on the pathway of folding of the β2-subunit of Escherichia coli tryptophan-synthetase

The kinetics of renaturation of the β₂-subunit of Escherichia coli tryptophan-synthetase (l-serine hydrolyase (adding indole) E.C. 4.2.1.20) and those of its two proteolytic fragments F₁ and F₂ are studied and compared. Steps corresponding to the refolding of F₁, to the association of the folded F₁ and F₂ fragments, and to an isomerization of the associated protein are identified. These steps are ordered on the pathway of renaturation and some of their kinetic parameters are determined. This leads to a tentative kinetic model for the renaturation of nicked-β₂ starting from the denatured F₁ and F₂ fragments.The step corresponding to the refolding of the F₁ domain, as well as that corresponding to the last rate-limiting isomerization leading to the native protein, is shown to be the same in the refolding of the entire, uncleaved β₂-protein. It is concluded that the refolded F₁ fragment corresponds to a folding intermediate on the pathway of renaturation of the β₂-subunit.