Characterization of Gilbert-like syndrome in squirrel monkeys (Saimiri sciureus)

Bolivian squirrel monkeys, unlike those of Brazilian origin, exhibit a marked fasting hyperbilirubinemia (FH) similar to that observed in Gilbert's syndrome in man. Since no delays in the hepatic clearance of sulfobromophthalein or indocyanine green are present, the Bolivian monkey appears to be similar to Gilbert's type I syndrome. FH can be significantly decreased by either phenobarbital or tin-protoporphyrin pretreatment. Nicotinic acid-induced hyperbilirubinemia and delayed tolbutamide clearance were not observed as in the human syndrome.     

Detection and cultivation of intestinal trichomonads of squirrel monkeys (Saimiri sciureus)

Routine examinations of fecal samples from squirrel monkeys suggested that intestinal trichomonads might be common inhabitants of these animals. In pursuit of these observations, microscopic examination of fecal suspensions and cultures have demonstrated a 100% incidence of trichomonads in 30 arbitrarily selected animals from a colony of more than 300 housed in groups of ten. The most prominent species was Pentatrichomonas hominis. A not yet fully characterized tritrichomonad was also found on several occasions. The main obstacle in establishing individual strains in culture was the presence of bacterial and fungal flora in the samples. Nevertheless, abundant cultures were obtained from 28 animals by inoculation of fecal suspensions into tissue cultures with appropriately formulated medium and high concentration of antibiotics. In several unattended cultures maintained at room temperature, the flagellates retained motility for at least 4 months. This long survival may explain the widespread occurrence of the parasites within a confined animal community.     

Adaptation of the Plasmodium falciparum FCB strain for in vitro and in vivo analysis in squirrel monkeys (Saimiri sciureus)

The asexual blood stages of the Plasmodium falciparum parasite are responsible for inducing the clinical symptoms and the most severe presentations of malaria infection that causes frequent mortality and morbidity in tropical and subtropical areas of the world, making the blood stages of infection a key target of new malaria treatment and prevention strategies. Progress towards the development of more effective treatment and prevention strategies has been hindered by the limited availability of infection models that permit the sequential analysis of blood stage parasites in vitro followed by in vivo analysis to confirm therapeutic benefits. To advance a model for in vitro and in vivo analysis of blood stage parasites, we examined nine laboratory strains of P. falciparum to determine which strains could adapt to growth in vivo in splenectomized squirrel monkeys (Saimiri sciureus). Only one of the nine laboratory strains tested, the FCB strain, adapted to in vivo growth. Morphological analysis show that the adapted ring-stage parasites have a different morphology from original parasites cultured in vitro, and more often they were found to localize at the edge of the infected red blood cell. No remarkable differences were observed for both trophozoites and schizonts. The adapted strain can be cultured back in vitro similar to the original parasite, indicating that the adapted parasite can develop both in vitro and in vivo. This squirrel monkey-adapted P. falciparum parasite is expected to be suitable and is advantageous for the research and development of vaccines and antimalarial drugs.     

Vaccination of squirrel monkeys (Saimiri spp.) with nanoparticle-based Toxoplasma gondii antigens: new hope for captive susceptible species

Squirrel monkeys (Saimiri spp.), new world primates from South America, are very susceptible to toxoplasmosis. Numerous outbreaks of fatal toxoplasmosis in zoos have been identified around the world, resulting in acute respiratory distress and sudden death. To date, preventive hygiene measures or available treatments are not able to significantly reduce this mortality in zoos. Therefore, vaccination seems to be the best long-term solution to control acute toxoplasmosis. Recently, we developed a nasal vaccine composed of total extract of soluble proteins of Toxoplasma gondii associated with muco-adhesive maltodextrin-nanoparticles. The vaccine, which generated specific cellular immune responses, demonstrated efficacy against toxoplasmosis in murine and ovine experimental models. In collaboration with six French zoos, our vaccine was used as a last resort in 48 squirrel monkeys to prevent toxoplasmosis. The full protocol of vaccination includes two intranasal sprays followed by combined intranasal and s.c. administration. No local or systemic side-effects were observed irrespective of the route of administration. Blood samples were collected to study systemic humoral and cellular immune responses up to 1 year after the last vaccination. Vaccination induced a strong and lasting systemic cellular immune response mediated by specific IFN-γ secretion by peripheral blood mononuclear cells. Since the introduction of vaccination, no deaths of squirrel monkeys due to T. gondii has been observed for more than 4 years suggesting the promising usage of our vaccine. Moreover, to explain the high susceptibility of naive squirrel monkeys to toxoplasmosis, their innate immune sensors were investigated. It was observed that Toll-like and Nod-like receptors appear to be functional following T. gondii recognition suggesting that the extreme susceptibility to toxoplasmosis may not be linked to innate detection of the parasite.     

The complete mitochondrial genome of Accipiter virgatus and evolutionary history of the pseudo-control regions in Falconiformes

The complete mitochondrial genome sequence of Accipiter virgatus was determined. This mt-genome was 17,952 bp in length and consisted of 22 tRNA genes, 13 protein-coding genes, 2 rRNA genes, one control region (CR) and one pseudo-control region (CCR). Phylogenetic analyses of 14,644 bp of mitochondrial DNA (12 protein-coding genes, 2 rRNAs and 22 tRNAs) revealed the phylogenetic position of Cathartidae (Cathartes aura) was more closer to Ciconiidae (storks) than Accipitridae. To investigate the divergence times of the CCRs in Falconiformes, detailed analyses of the noncoding regions (CR and CCR) were performed. We found the recently reported novel gene order in Falconiformes had multiple independent origins and hence cannot be used to infer phylogenetic lineages. Indeed, the molecular clock suggested the CCR in Falconidae emerged about 65.4 million years (Mya), while that in Pandionidae–Accipitridae clade emerged about 19.16 Mya. The intra-genomic homology between the noncoding regions was detected in Spilornis cheela, which supporting the duplication hypothesis. Furthermore, the structure of CCR should be featured by a region containing tandem repeats as two definitely separated clusters of tandem repeats were found. The findings presented here should be considered in future phylogenetic and evolutionary studies targeting the pseudo-control regions of all Falconiformes species.     

Higher-level salamander relationships and divergence dates inferred from complete mitochondrial genomes

Phylogenetic relationships among the salamander families have been difficult to resolve, largely because the window of time in which major lineages diverged was very short relative to the subsequently long evolutionary history of each family. We present seven new complete mitochondrial genomes representing five salamander families that have no or few mitogenome records in GenBank in order to assess the phylogenetic relationships of all salamander families from a mitogenomic perspective. Phylogenetic analyses of two data sets—one combining the entire mitogenome sequence except for the D-loop, and the other combining the deduced amino acid sequences of all 13 mitochondrial protein-coding genes—produce nearly identical well-resolved topologies. The monophyly of each family is supported, including the controversial Proteidae. The internally fertilizing salamanders are demonstrated to be a clade, concordant with recent results using nuclear genes. The internally fertilizing salamanders include two well-supported clades: one is composed of Ambystomatidae, Dicamptodontidae, and Salamandridae, the other Proteidae, Rhyacotritonidae, Amphiumidae, and Plethodontidae. In contrast to results from nuclear loci, our results support the conventional morphological hypothesis that Sirenidae is the sister-group to all other salamanders and they statistically reject the hypothesis from nuclear genes that the suborder Cryptobranchoidea (Cryptobranchidae + Hynobiidae) branched earlier than the Sirenidae. Using recently recommended fossil calibration points and a “soft bound” calibration strategy, we recalculated evolutionary timescales for tetrapods with an emphasis on living salamanders, under a Bayesian framework with and without a rate-autocorrelation assumption. Our dating results indicate: (i) the widely used rate-autocorrelation assumption in relaxed clock analyses is problematic and the accuracy of molecular dating for early lissamphibian evolution is questionable; (ii) the initial diversification of living amphibians occurred later than recent estimates would suggest, from the Late Carboniferous to the Early Permian (294 MYA); (iii) living salamanders originated during the Early Jurassic (183 MYA), and (iv) most salamander families had diverged from each other by Late Cretaceous. A likelihood-based ancestral area reconstruction analysis favors a distribution throughout Laurasia in the Early Jurassic for the common ancestor of all living salamanders.     

Genetically determined antigens of squirrel monkey (Saimiri sciureus) IgG

Alloantigens of squirrel monkey (Saimiri sciureus) IgG were studied using alloantisera prepared by cross-immunizations among four subspecies. The results demonstrated the occurrence of IgG antigenic polymorphism. Three distinct Fd fragment allotypes were detected. Greater alloantigenic complexity occurred among Colombian and Peruvian squirrel monkeys, which occupy the more central regions of the geographic range; Bolivian and Guyanan monkeys, which occupy the extremes of the range, expressed less alloantigenic complexity.     

Molecular characterization of major histocompatibility complex class 1 (MHC-I) from squirrel monkeys (<Emphasis Type="Italic">Saimiri sciureus</Emphasis>)

Little is known about the major histocompatibility complex (MHC) class 1 in squirrel monkeys (Saimiri sciureus). We cloned, sequenced and characterized two alleles and the cDNA of the coding region of MHC class 1 in these New World monkeys. Phylogenetic analyses showed that these sequences are related to HLA class 1 genes (HLA-A and HLA-G). The structure and organization of one of the two identified clones was similar to that of a class 1 MHC gene (HLA-A2). All the exon/intron splice acceptor/donor sites are conserved and their locations correspond to the HLA-A2 gene. The sequences of the newly described cDNAs reveal that they code for the characteristic class 1 MHC proteins, with all the features thought necessary for cell surface expression. Typical sequences for the leader peptide, ₁, ₂, ₃, transmembrane and cytoplasmic domains were found.The nucleotide sequence data reported in this paper have been submitted to the GenBank database and have been assigned the accession numbers AJ438576 (Sasc-G*31), AJ438577 (Sasc-G*25), AY282760 (Sasc-G*03), AY282761 (Sasc-G*04) and AY282762 (Sasc-G*05). Sequences were named as recommended by Klein and co-workers (1990)     

Pentastomid nymph from the brain of a squirrel monkey (Saimiri sciureus). II. Morphology of the host response

A Porocephalus nymph found in the meninges of a squirrel monkey was encapsulated by connective tissue cells and fibrils presumably derived from the pia mater. The capsule was composed of an inner layer (IL) adjacent to the nymphal integument and an outer layer (OL) adherent to the brain surface. Separating the two layers was a capsular space. The IL was lined by a granular material adjacent to the nymph surface and possessed impressions of annulae and the apical pits of chloride cells. The surface of IL facing the capsular space was characterized by a monolayer of cells possessing extensive anastomosing plasmalemmal processes. The OL was composed of several tiers of fibroblasts and associated collagen fibrils that adhered to the brain surface in the form of a thickened pia mater. It is suggested that the capsule was formed by a modification of the pia that isolated the nymph and created an "intracapsular space" with specialized lining cells to facilitate fluid exchange.     

Synchronization of weaning time with peak fruit availability in squirrel monkeys (Saimiri collinsi) living in Amazonian Brazil

Many mammals coincide their reproductive activities with factors such as ambient temperature, rainfall, and food availability. In primates that invest immediate food intake into reproduction, the periods of maximum fruit production often coincide with the peak of lactation (to maximize maternal survival) or the occurrence of weaning (to maximize infant survival). This study investigates the relationship between reproductive periods and the availability of ripe fruit in the habitat of a population of wild squirrel monkeys (Saimiri collinsi) in Amazonian Brazil. We combine data from several years (2002–2003; 2011–2015) during which we followed the monkeys and quantified the occurrence of matings, gestations, births, and the number of lactating females. We also collected rainfall and plant phenological data for 24 months. Our results confirm that reproductive events are highly seasonal in S. collinsi. The period of weaning corresponded to the peak in the abundance of ripe fruits consumed by the monkeys. This indicates that the period of infant nutritional independence is optimally timed to coincide with periods of greater food production in this habitat. We suggest that seasonal breeding in these primates does not necessarily reduce maternal energetic stress, but likely improves infant survivorship.     

A study of correlates of hand preferences in squirrel monkeys (Saimiri sciureus)

The purpose of this study was to test the influence of sex, age, social rank, matriline membership, posture, and visual and tactual motor control on manual preferences inSaimiri sciureus. A well-established social group of 12 squirrel monkeys, aged 2 to 14 yrs and consisting of two matrilines with social rank known for each animal, was presented with four different food-reaching tasks and assessed for hand preferences with a minimum of 100 reaches per animal. Frequency of occurrence of hand preferences at the group level and degree of hand preferences at the individual level depended on posture and on whether the reaching act took place under visual or tactual guidance. Sex, age, social rank, and matriline membership were not found to determine frequency of occurrence, direction or degree of hand preferences with the exception of one task in which a significant negative correlation between the degree of hand preference and age was found. Nine out of 12 monkeys showed task-dependent changes in the hand they used preferentially while only three animals preferred the same hand in all four tasks. Significant preferences for the use of right or left hand on a given task were distributed almost equally between individuals. Thus, the results of this study suggest task-specific demands like posture and/or whether reaching was visually or tactually guided to be the major correlates of hand preferences in food-reaching tasks in squirrel monkeys.     

Discriminating parts from the whole: determinants of odor mixture perception in squirrel monkeys,Saimiri sciureus

In a task designed to simulate olfactory-guided foraging, the ability of squirrel monkeys to discriminate an artificial 12-component odorant from 3-, 6-, 9- or 11- component submixtures was investigated. A combination of factors was found to contribute to the animals' performance:

Morphometric analysis of the zona pellucida and ooplasm of squirrel monkey (Saimiri sciureus) eggs

The objective of this study was to correlate the thickness of the zona pellucida (zona) with egg (oocyte) maturity determined through a widely-used method of assessing oocyte maturation namely, the evidence for cumulus and corona cells expansion. Measurements of the zona of cultured oocytes were recorded at 0, 3, 6, 24, and 48 hr after laparoscopic oocyte retrieval from hormonallystimulated squirrel monkeys. The results indicated that at the time of oocyte retrieval, oocytes that were classified as mature had thicker zonae compared with immature oocytes. The zona layer of the mature oocyte expanded to a maximum after 6 hr of incubation while the zona layer of the immature oocyte became compressed. The diameter of the mature oocyte (minus the zona and perivitelline space) became smaller with time while the immature oocyte diameter remained relatively unchanged. The correlation between the maturational state of the oocyte and the thickness of the zona layer suggest the possible application of zona morphometric evaluations as an indicator of oocyte maturation.     

Molecular phylogenetic relationships among Sichuan snub-nosed monkeys (Rhinopithecus roxellanae) inferred from mitochondrial cytochrome-b gene sequences

The Sichuan snub-nosed monkey (Rhinopithecus roxellanae) is a species endemic to China, and its distribution is the widest among all snub-nosed monkeys in China. To clarify whether there is subspecific differentiation within this species, we determined partial sequences of the cytochrome-b gene from four populations ofR. roxellanae. First, 402bps of the partial sequences fromR. roxellanae were compared with those fromR. bieti andR. avunculus, and the phylogenetic tree was constructed by the neighbor-joining method. The genetic distance was only 0–0.002 among the four populations, and their sequences constituted a monophyletic group. Further, comparison of longer sequences (735bp) among the four populations revealed that there were only four substitutions and the genetic distance was only 0.001–0.005 among them. Thus, we suggest that, at least on mtDNA phylogeny, the difference among the four populations does not reach the subspecies level, and that this species should be recognized as a monotypic species.     

Molecular systematics of theDrosophila hydei subgroup as inferred from mitochondrial DNA sequences

The phylogeny of theDrosophila hydei subgroup, which is a member of theD. repleta species group, was inferred from 1,515 base pairs of mitochondrial DNA sequence of the cytochrome oxidase subunits I, II, and III. Four of the seven species in the subgroup were examined, which are placed into two taxonomic complexes: theD. bifurca complex (D. bifurca) andD. nigrohydei) and theD. hydei complex (D. hydei and (D. eohydei). Both complexes appear to be monophyletic, although theD. bifurca complex is only weakly supported. The evolution of chromosomal change, interspecific crossability, sperm gigantism, and divergence times of the subgroup is discussed in a phylogenetic context. Correspondence to: G. Spicer     

Osmotic fragility of erythrocytes in Bolivian and Brazilian squirrel monkeys (Saimiri sciureus).

Median corpuscular fragility of erythrocytes does not differ significantly between fed and fasted Bolivian and Brazilian squirrel monkeys and are similar to values reported in humans and rhesus monkeys. This report further confirms that the fasting hyperbilirubinemia present only in Bolivian squirrel monkeys with a Gilbert-like syndrome is not due to an increased fragility of erythrocytes and should be classified as a nonhemolytic hyperbilirubinemia.     

Conditions of failure and recovery of maternal behavior in captive squirrel monkeys (Saimiri)

This paper deals with the functioning and malfunctioning of maternal behavior in relation to external and social conditions. During developmental studies in captive squirrel monkey groups, 49 mother-infant pairs were observed. There were several cases of maternal inadequacy subsequent to (1) postnatal transportation, (2) exaggerated social investigation by immatures,and (3) premature allomothering. Brief mother-infant separations by humans did not yield such failures. One female consistently prevented nursing with at least three of her five viable offspring. Complete or partial failure of maternal behavior did not preclude subsequent recovery and/or adequate allomothering. Dedicated to Prof. Dr. Med. Detlev Ploog on the occasion of his 60th birthday.     

Molecular phylogeny of gibbons inferred from mitochondrial DNA sequences: Preliminary report

We analyzed the 896 base-pair (bp) mitochondrial DNA (mtDNA) sequences for seven gibbons, representative of three out of four subgenera. The result from our molecular analysis is consistent with previous studies as to the monophyly of subgenus Hylobates species, yet the relationship among subgenera remains slightly ambiguous. A striking result of the analysis is the phylogenetic location of Kloss's gibbon (H. klossii). Kloss's gibbon has been considered to be an initial off-shoot of the subgenus Hylobates because of its morphological primitiveness. However, our molecular data strongly suggest that Kloss's gibbon speciated most recently within the subgenus Hylobates. Correspondence to: S. Horai