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At least 19 recordsLinked to original sources
PubMed1979

Acid-base curve nomogram for chimpanzee blood and comparison with human blood characteristics.

An acid-base nomogram for chimpanzee blood was constructed. Blood was drawn from eight lightly anesthetized chimpanzees. Each sample of blood was oxygenated and nine aliquots were prepared with three different concentrations of hemoglobin and three different amounts of added acid or base. Each aliquot was equilibrated at two PCO2 levels and the pH was measured and plotted on pH-logPCO2 coordinates. Using the intersection point of these pH-logPCO2 lines as a point of equal hemoglobin-independent "base excess" for each condition, values for true base excess were plotted. Connecting these values provided a Cartesian PCO2-pH base excess nomogram for the chimpanzee comparable to that devised by Siggaard-Andersen for humans. Examination of blood from normal human subjects by the same methods showed no appreciable differences from the original Siggaard-Andersen nomogram. However, the PCO2-pH-base excess nomogram for chimpanzee blood deviated slightly from that for human blood. It is possible that the deviation is related to an arterial bicarbonate concentration in the chimpanzee slightly higher than that in human.

Acid-Base Equilibrium↗
PubMed2026

A new southern limit for the distribution of African great apes: sympatric western lowland gorilla (Gorilla gorilla gorilla) and central chimpanzee (Pan troglodytes troglodytes) confirmed in Mayombe National Park, Angola.

The distribution of African great apes has remained unconfirmed regarding their southern limit, particularly on the western side of the continent. IUCN maps include the Mayombe forest of Angola as part of the estimated distribution of western lowland gorillas (Gorilla gorilla gorilla) and central chimpanzees (Pan troglodytes troglodytes). However, until now no published evidence-based records had confirmed the continued presence of both species. The Mayombe forest is a key biodiversity hotspot and a potentially important stronghold for the conservation of great ape populations in Africa. Here, we report the first systematic evidence of both species in the Mayombe National Park, Cabinda, Angola. In 2023, a grid of camera traps was systematically deployed, producing the first visual records of gorillas and chimpanzees. Building on these findings, in 2024, a pilot survey including ad libitum field observations was carried out along exploratory trails to maximise data collection. The combination of these records identified a hotspot of great ape activity where six transects were established, and systematic direct and indirect evidence was documented. Chimpanzees were recorded more times across a broader range of evidence categories, while gorillas appeared less and seemed more spatially restricted. Notably, both species were detected at overlapping sites but never simultaneously, indicating sympatric coexistence with spatio-temporal partitioning. These findings confirm the southernmost predicted distribution of both species for this part of Africa, filling critical gaps in the understanding of great ape evolution and biogeography, and providing a baseline for the first demographic and ecological census of great apes in Angola.

Animals↗
PubMedDate not supplied

The metabolism of (2-cyclopentyl-6,7-dichloro-2-methyl-1-oxo-5-indanyloxy)acetic acid in chimpanzee and man.

The metabolism of the polyvalent saluretic agent (2-cyclopentyl-6,7-dichloro-2-methyl-1-oxo-5-indanyloxy)acetic acid was studied in chimpanzee and man. The drug was well absorbed and extensively metabolized by man. Peak levels of drug (5--8 microgram/ml) occurred within 1.5--4.5 hr of drug administration. The plasma half-life was estimated to be 2 hr; a similar half-life was observed in the chimpanzee. Little unchanged drug (less than 10%) was excreted in the urine of either species. Similar metabolic profiles were obtained for man and chimpanzee. The major urinary metabolites resulted from hydroxylation of the cyclopentyl moiety, giving rise to a number of diastereomers. The alcohol metabolites were subsequently oxidized to the ketone. The excretion of the metabolites coincided with maximal excretion of sodium and chloride ions. The hydroxylated metabolites have intrinsic pharmacological activity.

Animals↗
PubMed2026

STRONGYLID COINFECTIONS IN SYMPATRIC CHIMPANZEES AND GORILLAS FROM THE REPUBLIC OF THE CONGO REVEALED BY FECAL METAGENOMICS.

Soil-transmitted strongylid nematodes are common intestinal parasites of African great apes, yet most surveys have relied on microscopy or targeted PCR assays that are limited in taxonomic breadth and comparability across hosts. I reanalyzed 46 publicly available shotgun fecal metagenomes from sympatric central chimpanzees (Pan troglodytes troglodytes; n = 18) and western lowland gorillas (Gorilla gorilla gorilla; n = 28) in the Goualougo Triangle, Nouabalé-Ndoki National Park, Republic of the Congo, to test whether host species structures genus-level strongylid community composition and relative read signal. Non-host reads were classified against a custom strongylid-focused database targeting 4 genera repeatedly reported from African apes: Ancylostoma, Necator, Oesophagostomum, and Trichostrongylus. All 4 focal genera were detected in every library under baseline filtering, and multi-genus detection remained robust under increasingly stringent read-count thresholds. However, host species differed strongly in community composition. Chimpanzee libraries had relatively even genus-level profiles, whereas gorilla libraries were consistently Necator-dominated. Gorillas also had substantially higher relative strongylid read abundance. The results show that shotgun metagenomic reanalysis can recover host-structured strongylid community signals from wildlife samples and can complement targeted parasitological surveys in conservation and One Health surveillance.

Animals↗
PubMedDate not supplied

The biotransformation of (6,7-dichloro-2-methyl-1-oxo-2-phenyl-5-indanyloxy) acetic acid (MK-196) in the chimpanzee.

The metabolism of a novel polyvalent saluretic agent (6,7-dichloro-2-methyl-1-oxo-2-phenyl-5-indanyloxy)acetic acid (MK-196) was studied in the chimpanzee. Following oral administration, 50% of the radioactive dose was recovered in the urine in four days; 8-14% of the dose was excreted as unchanged drug. The fecal specimens accounted for 5-9% of the dose. Following intravenous administration an initial rapid elimination of drug from the plasma was observed [(t1/2)alpha approximately 0.4 hr, (t1/2)beta approximately 4 hr]. The data are consistent with the rapid elimination of radioactivity, approximately 30% of dose, in the urine during the first 24 hr, followed by a much slower rate of excretion of drug and metabolites. These findings are congruous with the high affinity (greater than 98%) of MK-196 and the major metabolite with plasma proteins. The urinary metabolites were isolated and identified by the following techniques: solvent extraction, column, thin-layer, and gas-liquid chromatography, derivatization, and mass and nuclear magnetic resonance spectroscopy. The major metabolite, which resulted from para-hydroxylation of the 2-phenyl substitutent, accounted for about 40% of the urinary radioactivity. Reduction of the ketone group, methylation of the p-hydroxy group, and additional phenyl ring hydroxylation were also shown to occur. There was no evidence for glucuronide formation nor did SKF-525-A inhibit the metabolism of the drug in the chimpanzee. Under conditions of induced metabolic alkalosis, the urinary levels of MK-196 increased from 11 to 40%. Probenecid and p-aminohippurate administered during metabolic alkalosis decreased the clearance of drug (40 to 15%).

Administration, Oral↗
PubMed1977

Saluretic and uricosuric effects of (6, 7-dichloro-2-methyl=1-oxo-2-phenyl-5-indanyloxy) acetic acid (MK-196) in the chimpanzee.

The saluretic and uricosuric responses elicited by a novel agent, MK-196, have been studied in a great ape, the chimpanzee. This agent is orally active at very low doses and has a prolonged duration of action. Probenecid does not appear to influence the saluretic and uricosuric properties of MK-196. Net tubular secretion of urate was reduced by MK-196. Urinary pH changes did not compromise the efficacy of this new agent. On a dose basis, MK-196 was more saluretic (and uricosuric) than ethacrynic acid or furosemide and possessed a longer duration of action. Because of the marked natriuresis caused by MK-196, some increase in potassium excretion occurred.

Animals↗
PubMed1977

Renal excretion of a slauretic-uricosuric agent (MK-196) and interaction with a urate-retaining drug, pyrazinoate, in the chimpanzee.

The excretory pattern for MK-196 is ocmpatible with that of other weak organic acids such as salicylate and probenecid. Tubular secretion of MK-196 is strongly inhibitied by probenecid and high loads of p-aminohippurate. Urinary excretion of MK-196 is increased 10-fold when the urine is alkaline. Clearances of MK-196 were not corrected for plasma protein binding of the drug which is very high (greater than 99%). Bidirectional transport processes are operative in that MK-196 is secreted by the renal tubule and passively back diffuses across the tubular epithelium by a pH-dependent process. MK-196 is able to overcome pyrazinoate-induced urate retention, whereas probenecid is not when studied by conventional clearance techniques. The uricosuric activity of MK-196 appears to be somewhat less with pyrazinoate than in its absence. When MK-196 is administered prior to pyrazinoate an attenuated uricosuric response was observed. This finding cannot be ascribed to a temporal decline in uricosuric action. Diuresis and saluresis produced by MK-196 are not influenced by pyrazinoate. The interaction of MK=196 and pyrazinoate on urate excretion is in direct contrast to results obtained with probenecid and pyrazinoate. A model has been proposed to explain this unique finding.

Acetazolamide↗
PubMed1976

Malaria of the orang-utan (Pongo pygmaeus) in Borneo.

The primary objective of this project was to study the life cycle and ecology of Plasmodium pitheci, a malaria parasite of the orang-utan. The field work was based on the orang-utan rehabilitation centre in the Sepilok Forest Reserve of eastern Sabah. Two visits were made to Sepilok, the first in February and March, 1972, and the second (by W.P.) in January 1974. On the first visit two species of "surrogate host" were taken to Sabah, i.e. chimpanzees and Aotus monkeys for experimental work. The arboreal habitat of the orang-utan in the dipterocarp forests of eastern Sabah is described. In the Sepilok Forest Reserve dwell gibbons and leaf-monkeys, in addition to a small population of semi-domesticated and wild, free-ranging orang-utans of various ages. Although numerous species of anopheline mosquitoes have been collected in eastern Sabah, longitudinal studies are not available. Anopheles balabacensis was caught both attracted to orang-utans and to man at Sepilok. This species which is the main vector of human malaria in the north of Borneo, is suspected also of transmitting orang-utan malaria in this part of Sabah. Repeated blood examinations have been made on a number of orang-utans in the centre since 1966 and a high prevalence of infection was recorded with Plasmodium pitheci. In 1966 10 out of 19 animals had demonstrable parasitaemia. Detailed case histories are presented to show the course of parasitaemia in several orang-utans. Infections of P. pitheci were found to run a very chronic course. During the 1972 expedition a second, previously undescribed malaria parasite of the orang-utan was discovered, and was named P. silvaticum. The new parasite was successfully transmitted both by blood inoculation and, later, by sporozoite inoculation, into splenectomized chimpanzees. Although both species of malaria parasite may cause transitory signs of illness, orang-utans in general appear to be little discomforted by the infection. The animals do however suffer from other infectious diseases such as amoebic and balantidial dysentery, and melioidosis is a serious natural hazard which may have accounted for several deaths of wild orang-utans. An unidentified, intraerythrocytic structure that appeared in the blood of one chimpanzee, which had been inoculated with blood from an orang-utan, may have contributed to its death. Detailed descriptions and illustrations of P. pitheci and P. silvaticum are given. All stages of the life cycle of P. silvaticum are known (the tissue stages having been described in the liver of a "surrogate host", the chimpanzee) but only the blood and sporogonic stages of P. pitheci have been seen. This species was not infective to a chimpanzee, although there is an earlier report of a transient infection in this host by other workers. In the blood both parasites showed a tertian periodicity. From the appearance of the tissue schizonts on the seventh day it was estimated that the complete pre-erythrocytic cycle of P. silvaticum in the chimpanzee would occupy 8 days. P...

Animals↗
PubMed1976

Experimental studies on the transmission of hepatitis B by mosquitoes.

Culex tarsalis and Aedes aegypti mosquitoes were fed on chimpanzees carrying hepatitis B surface antigen (HBS Ag) of known infectivity and pools were tested by radioimmunoassay daily for the presence of HBS Ag. HBS Ag continued to be detected at low levels in mosquito tissue after digestion of the blood meal. Inoculation of susceptible chimpanzees with macerated pools of A. aegypti mosquitoes at two intervals after digestion of the blood meal did not produce hepatitis or serologic evidence of hepatitis B virus infection. Mechanical transmission studies by interrupting feeding of A aegypti from HBS Ag-carrier chimpanzees and transferring them to susceptible chimpanzees did not produce hepatitis. These findings do not support the hypothesis that mosquitoes are involved in either biological or mechanical transmission of hepatitis B.

Aedes↗
PubMedDate not supplied

A solution to the graft-versus-host problem in bone marrow transplantation to humans.

Many clinical situations arise where it would be desirable to transplant bone marrow to a marrow function deficient patient. However, bone marrow is immunologically competent by virtue of its content of lymphocyte precursors. Marrow transplantation in these patients is followed by the graft's immunological rejection of the patient - a fatal disease. A system for specific abrogation of this graft-versus-host disease after xenogeneic bone marrow transplantation to humans is presented. In this system, prospective patient cells are removed by skin biopsy for example, and injected into a fetal chimpanzee. The fetal chimpanzee becomes tolerant to this patient's antigens and will not attack or reject them when its bone marrow is removed after birth and injected into the specific patient from whom the tolerogenic cells were obtained. A simple and straightforward experimental test of this system's clinical applicability is also presented.

Animals↗
PubMed2026

Nuclear mitochondrial sequences in great ape telomere-to-telomere genomes.

Mitochondrial sequences have integrated into the nuclear genome since the origin of eukaryotes. Recent insertions that retain homology with extant mitochondrial DNA (mtDNA), termed NUMTs, confound mtDNA sequence analysis. Here, we use great ape telomere-to-telomere (T2T) genomes to study NUMTs in bonobo, chimpanzee, human, gorilla, and Bornean and Sumatran orangutans. A phylogeny based on shared and lineage-specific NUMTs accurately recapitulates the great ape species tree topology. NUMTs are enriched at nonfunctional nonrepetitive regions of the nuclear genome and depleted within enhancers and coding sequences, suggesting negative selection. We validate the presence of a 76-kb-long heterozygous NUMT in chimpanzee, which is larger than any other NUMT observed in great apes, and find that dozens of NUMTs on the Pan Y Chromosome expanded together with palindromes. Finally, by analyzing intra-specific variation, we confirm that the vast majority of species-specific NUMTs identified in T2T assemblies are fixed or present at high frequencies in each species. Our study highlights NUMTs as a dynamic evolutionary force contributing to shaping ape genomes and is valuable for characterizing mtDNA in great apes.

Journal Article↗
PubMed1975

Testis antigens of man and some other primates.

Rabbit antisera raised aginst testis preparations of human, chimpanzee, rhesus monkey, and baboon origin were used to study testis-specific antigens within and among the four primate species. Antisera were absorbed with serum, liver, kidney, and spleen preparations of the respective species against which they had been produced. Immunoelectrophoretic analysis of testis extracts, using the absorbed antisera, indicated the following minimum numbers of testis-specific antigens for each species: man, 10; chimpanzee, 8; rhesus monkey, 10; and baboon, 8. Most of the testis antigens were cross-reactive among species. The results suggest that human spermatozoa possess at least four to five specific antigens which originate in the testis. The antigen that induces sperm-immobilizing antibody cross-reacted among the four species of primates. Human and rhesus monkey sperm reacted equally in the immobilization system. Testis extracts from each primate species were capable of removing the sperm-immobilizing activity of human immune sera by absorption. Testis proteinase activity, as determined by using a gelatin membrane substrate, was inhibited by the gamma-glogulin fractions of rabbit and rhesus monkey antisera and also appeared to be cross-reactive among the species.

Animals↗
PubMed2024

Sequencing the orthologs of human autosomal forensic short tandem repeats provides individual- and species-level identification in African great apes.

BACKGROUND: Great apes are a global conservation concern, with anthropogenic pressures threatening their survival. Genetic analysis can be used to assess the effects of reduced population sizes and the effectiveness of conservation measures. In humans, autosomal short tandem repeats (aSTRs) are widely used in population genetics and for forensic individual identification and kinship testing. Traditionally, genotyping is length-based via capillary electrophoresis (CE), but there is an increasing move to direct analysis by massively parallel sequencing (MPS). An example is the ForenSeq DNA Signature Prep Kit, which amplifies multiple loci including 27 aSTRs, prior to sequencing via Illumina technology. Here we assess the applicability of this human-based kit in African great apes. We ask whether cross-species genotyping of the orthologs of these loci can provide both individual and (sub)species identification. RESULTS: The ForenSeq kit was used to amplify and sequence aSTRs in 52 individuals (14 chimpanzees; 4 bonobos; 16 western lowland, 6 eastern lowland, and 12 mountain gorillas). The orthologs of 24/27 human aSTRs amplified across species, and a core set of thirteen loci could be genotyped in all individuals. Genotypes were individually and (sub)species identifying. Both allelic diversity and the power to discriminate (sub)species were greater when considering STR sequences rather than allele lengths. Comparing human and African great-ape STR sequences with an orangutan outgroup showed general conservation of repeat types and allele size ranges. Variation in repeat array structures and a weak relationship with the known phylogeny suggests stochastic origins of mutations giving rise to diverse imperfect repeat arrays. Interruptions within long repeat arrays in African great apes do not appear to reduce allelic diversity. CONCLUSIONS: Orthologs of most human aSTRs in the ForenSeq DNA Signature Prep Kit can be analysed in African great apes. Primer redesign would reduce observed variability in amplification across some loci. MPS of the orthologs of human loci provides better resolution for both individual and (sub)species identification in great apes than standard CE-based approaches, and has the further advantage that there is no need to limit the number and size ranges of analysed loci.

Animals↗
PubMed2026

A Multiepitope Intranasal Adenoviral Vaccine Induces Robust Mucosal Immunity and Protection against SARS‑CoV‑2.

BACKGROUND: Vaccination has been central to mitigating the COVID-19 pandemic; however, the continual emergence of SARS-CoV-2 variants of concern (VOCs) has reduced the effectiveness of current intramuscular vaccines that primarily target the Spike (S) protein. Although updated formulations are periodically introduced, there remains a critical need for next-generation vaccine platforms capable of inducing broad, variant-independent protection. Here we evaluate a heterologous intranasal (i.n.) prime-boost vaccination strategy using bovine adenoviral (BAd) and chimpanzee adenoviral (ChAd) vectors expressing the S1 subunit in combination with either full-length membrane (M) and nucleocapsid (N) proteins (Ad-S1 + N + M) or multiepitope constructs derived from M and N (Ad-S1 + Epi/N + Epi/M). The constructs were incorporated with the autophagy-inducing peptide C5 (AIP-C5) to enhance antigen-specific T-cell responses. RESULTS: In BALB/c mice, Ad-S1 + Epi/N + Epi/M vaccination induced robust S1-specific immunity while simultaneously inducing strong N- and M-specific humoral and cellular responses that were comparable to or greater than those induced by Ad-S1 + N + M. All S1-containing formulations generated high neutralizing antibody titers (~ 3.8 log₁₀) against Omicron B.1.1.529 and BA.2.86 variants, although titers against the ancestral Wuhan strain were approximately one log₁₀ lower. In K18-hACE2 mice, i.n. immunization with S1-expressing vectors provided near-complete protection against BA.2.86 challenge, with undetectable lung viral titers and viral genome copies. CONCLUSION: An i.n. multiepitope adenoviral vaccine incorporating conserved SARS-CoV-2 antigens induces robust mucosal, humoral, and cellular immune responses and confers significant protection following SARS-CoV-2 challenge.

Animals↗
PubMed2026

Regulatory Evolution and the Genetic Basis of Human Brain Expansion.

The evolution of the human brain is characterized by profound changes in structure and function, despite relatively limited divergence in protein-coding genes compared to other primates. This paradox has led to increasing recognition of gene regulatory elements (GREs) as primary drivers of evolutionary innovation. In this review, we synthesize current knowledge on the role of conserved noncoding elements (CNEs), human accelerated regions (HARs), and transposable element (TE)-derived sequences in shaping gene regulatory networks (GRNs) underlying brain development. Comparative analyses across humans and closely related primates, including the chimpanzee, gorilla, and orangutan, reveal that while core regulatory architectures are highly conserved, subtle changes in regulatory elements drive species-specific gene expression patterns. We highlight how CNEs provide a stable regulatory framework, whereas HARs and TE-derived elements introduce lineage-specific modifications that fine-tune neurodevelopmental processes. Advances in functional genomics, including CRISPR-based perturbations, massively parallel reporter assays, and single-cell multi-omics, have enabled direct interrogation of regulatory function, linking sequence variation to cellular phenotypes. Furthermore, we discuss how regulatory evolution contributes to both cognitive innovation and susceptibility to neurological disorders. Despite significant progress, challenges remain in establishing causal relationships between regulatory variation and phenotypic outcomes. Future integration of multi-omics data and comparative models will be essential for resolving these complexities. Together, this review provides a comprehensive framework for understanding the molecular basis of primate brain evolution through the lens of gene regulation.

Brain evolution↗
PubMed2026

Co-mutation Based Genetic Networks to Infer Temporal Mutation Dynamics in Ancient Human Mitochondrial Genomes.

The evolutionary history of Homo sapiens is marked by complex interactions between environmental, cultural, and genetic factors. To investigate the molecular signatures of these processes, we analyzed ancient mitochondrial DNA (mtDNA) across temporal and geographic contexts using principles of co-occurrence of minor alleles defined as co-mutation, through spatiotemporal co-mutation networks of variable sites. Haplogroup-based assessments of variable sites revealed a major transition from foraging to agrarian lifestyles during the Copper-Bronze Age. Genetic network analyses demonstrated that COX and CYB loci exhibited distinct temporal dynamics, with their interactions modulated by NADH dehydrogenase genes in a geological age-dependent manner. To complement the network approach, we constructed phylogeny-based gene interaction networks and assessed polymorphism-to-divergence from chimpanzee ratios. The tree-based networks displayed topologies consistent with co-mutation analyses but showed reduced gene-gene connectivity. Polymorphism/divergence analysis further indicated that the CYB gene has been under long-term purifying selection, whereas ATP6, COX, and NADH dehydrogenase genes experienced episodic purifying selection aligned with distinct historical phases. Collectively, our findings demonstrate that network-based analysis of ancient mtDNA provides insights into early human lifestyle transitions and haplogroup diversification, contributing to the evolutionary foundations of modern human populations.

Ancient humans↗
PubMed2026

Parting ways: Pan-Homo divergence revisited.

The timing of divergence between hominins and the bonobo-chimpanzee clade has been at the core of palaeoanthropological debate for over a century. The earliest molecular studies indicated divergence times ranging from 5 Ma to as recently as 1.3 Ma. This study critically reviews the trends of time estimates published between 1967 and 2023, and analyses how these are supported or rejected by the current molecular and fossil records. We compiled 202 divergence estimates and defined three distinct thresholds based on fossil evidence at 4.4 Ma (Australopithecus anamensis and Ardipithecus ramidus), 6.2 Ma (Orrorin tugenensis and Ardipithecus kadabba), and 7.2 Ma (Sahelanthropus tchadensis). We then used these thresholds to filter out molecular estimates that are too young to fit the fossil record. Overall, the data suggests a divergence event within the late Miocene, with each threshold pushing it further back, 8.63-6.38, 10.33-7.81, and 10.95-8.81 Ma, respectively. We use a quadratic regression to demonstrate that estimates have been slowly shifting from ~ 6 Ma to ~ 8.5 Ma over the past 56 years. A Bayesian meta-analysis of genomic estimates filtered by our most consensual threshold (i.e., assuming Australopithecus belongs to Hominini) indicates that the split must have occurred early in the late Miocene, most likely before 7 Ma (~ 99.5% posterior probability) with a pooled effect of 8.69-7.28 Ma. We conclude that, despite an initial bias towards younger estimates, the molecular timing for the last common ancestor (LCA) of Pan-Homo has been progressively approaching the intervals suggested by the current fossil record.

Animals↗