A Multispecies Approach to Co-Sleeping

Human sleeping arrangements have evolved over time and differ across cultures. The majority of adults share their bed at one time or another with a partner or child, and many also sleep with pets. In fact, around half of dog and cat owners report sharing a bed or bedroom with their pet(s). However, interspecies co-sleeping has been trivialized in the literature relative to interpersonal or human-human co-sleeping, receiving little attention from an interdisciplinary psychological perspective. In this paper, we provide a historical outline of the “civilizing process” that has led to current sociocultural conceptions of sleep as an individual, private function crucial for the functioning of society and the health of individuals. We identify similar historical processes at work in the formation of contemporary constructions of socially normative sleeping arrangements for humans and animals. Importantly, since previous examinations of co-sleeping practices have anthropocentrically framed this topic, the result is an incomplete understanding of co-sleeping practices. By using dogs as an exemplar of human-animal co-sleeping, and comparing human-canine sleeping with adult-child co-sleeping, we determine that both forms of co-sleeping share common factors for establishment and maintenance, and often result in similar benefits and drawbacks. We propose that human-animal and adult-child co-sleeping should be approached as legitimate and socially relevant forms of co-sleeping, and we recommend that co-sleeping be approached broadly as a social practice involving relations with humans and other animals. Because our proposition is speculative and derived from canine-centric data, we recommend ongoing theoretical refinement grounded in empirical research addressing co-sleeping between humans and multiple animal species.     

In vitro bioactive luteinizing hormone assay shows cyclical,seasonal hormonal changes and response to luteinizing-hormone releasing hormone in the squirrel monkey (Saimiri boliviensis boliviensis)

Studies on the reproductive mechanisms of the squirrel monkey have been hampered by inadequate measurements of luteinizing hormone (LH). The mouse interstitial cell bioassay, which measures testosterone production as the endpoint, was validated for use in the squirrel monkey by parallel responses of serum to LH standards and by in vivo responses to an LH-releasing hormone (LHRH) analogue. The LH surge profile, as determined by daily blood sampling, was found to be of 1–2 days duration and comparable in amplitude to those of other primates. A 9.7-day ovulatory cycle length was also calculated and was similar to previous estimates based on other hormonal and behavioral methods. A 150-fold decrease in basal LH was found in the nonbreeding season, as was a decreased LHRH response. This assay makes possible future studies on hypothalamic-ovarian mechanisms in this species.     

Reovirus sigmaNS protein is required for nucleation of viral assembly complexes and formation of viral inclusions

Progeny virions of mammalian reoviruses are assembled in the cytoplasm of infected cells at discrete sites termed viral inclusions. Studies of temperature-sensitive (ts) mutant viruses indicate that nonstructural protein sigmaNS and core protein mu2 are required for synthesis of double-stranded (ds) RNA, a process that occurs at sites of viral assembly. We used confocal immunofluorescence microscopy and ts mutant reoviruses to define the roles of sigmaNS and mu2 in viral inclusion formation. In cells infected with wild-type (wt) reovirus, sigmaNS and mu2 colocalize to large, perinuclear structures that correspond to viral inclusions. In cells infected at a nonpermissive temperature with sigmaNS-mutant virus tsE320, sigmaNS is distributed diffusely in the cytoplasm and mu2 is contained in small, punctate foci that do not resemble viral inclusions. In cells infected at a nonpermissive temperature with mu2-mutant virus tsH11.2, mu2 is distributed diffusely in the cytoplasm and the nucleus. However, sigmaNS localizes to discrete structures in the cytoplasm that contain other viral proteins and are morphologically indistinguishable from viral inclusions seen in cells infected with wt reovirus. Examination of cells infected with wt reovirus over a time course demonstrates that sigmaNS precedes mu2 in localization to viral inclusions. These findings suggest that viral RNA-protein complexes containing sigmaNS nucleate sites of viral replication to which other viral proteins, including mu2, are recruited to commence dsRNA synthesis.     

Avian reovirus temperature-sensitive mutant tsA12 has a lesion in major core protein sigmaA and is defective in assembly

Members of our laboratory previously generated and described a set of avian reovirus (ARV) temperature-sensitive (ts) mutants and assigned 11 of them to 7 of the 10 expected recombination groups, named A through G (M. Patrick, R. Duncan, and K. M. Coombs, Virology 284:113-122, 2001). This report presents a more detailed analysis of two of these mutants (tsA12 and tsA146), which were previously assigned to recombination group A. The capacities of tsA12 and tsA146 to replicate at a variety of temperatures were determined. Morphological analyses indicated that cells infected with tsA12 at a nonpermissive temperature produced approximately 100-fold fewer particles than cells infected at a permissive temperature and accumulated core particles. Cells infected with tsA146 at a nonpermissive temperature also produced approximately 100-fold fewer particles, a larger proportion of which were intact virions. We crossed tsA12 with ARV strain 176 to generate reassortant clones and used them to map the temperature-sensitive lesion in tsA12 to the S2 gene. S2 encodes the major core protein sigmaA. Sequence analysis of the tsA12 S2 gene showed a single alteration, a cytosine-to-uracil transition, at nucleotide position 488. This alteration leads to a predicted amino acid change from proline to leucine at amino acid position 158 in the sigmaA protein. An analysis of the core crystal structure of the closely related mammalian reovirus suggested that the Leu(158) substitution in ARV sigmaA lies directly under the outer face of the sigmaA protein. This may cause a perturbation in sigmaA such that outer capsid proteins are incapable of condensing onto nascent cores. Thus, the ARV tsA12 mutant represents a novel assembly-defective orthoreovirus clone that may prove useful for delineating virus assembly.     

Genomic affinities in Arachis section Arachis (Fabaceae): molecular and cytogenetic evidence

Section Arachis is the largest of nine sections in the genus Arachis and includes domesticated peanut, A. hypogaea L. Most species are diploids (x=10) with two tetraploids and a few aneuploids. Three genome types have been recognized in this section (A, B and D), but the genomes are not well characterized and relationships of several newly described species are uncertain. To clarify genomic relationships in section Arachis, cytogenetic information and molecular data from amplified fragment length polymorphism (AFLP) and the trnT-F plastid region were used to provide an additional insight into genome composition and species relationships. Cytogenetic information supports earlier observations on genome types of A. cruziana, A. herzogii, A. kempff-mercadoi and A. kuhlmannii but was inconclusive about the genome composition of A. benensis, A. hoehnei, A. ipaensis, A. palustris, A. praecox and A. williamsii. An AFLP dendrogram resolved species into four major clusters and showed A. hypogaea grouping closely with A. ipaensis and A. williamsii. Sequence data of the trnT-F region provided genome-specific information and showed for the first time that the B and D genomes are more closely related to each other than to the A genome. Integration of information from cytogenetics and biparentally and maternally inherited genomic regions show promise in understanding genome types and relationships in Arachis.     

The simple repeat poly(dT-dG).poly(dC-dA) common to eukaryotes is absent from eubacteria and archaebacteria and rare in protozoans

Genomic DNA from a wide variety of prokaryotic and eukaryotic organisms has been assayed for the simple repeat sequence poly(dT-dG).poly(dC-dA) by Southern blotting and DNA slot blot hybridizations. Consistent with findings of others, we have found the simple alternating sequence to be present in multiple copies in all organisms in the animal kingdom (e.g., mammals, reptiles, amphibians, fish, crustaceans, insects, jellyfish, nematodes). The TG element was also found in lower eukaryotes (Saccharomyces cerevisiae, Neurospora crassa, and Dictyostelium discoideum) and at a much lower frequency in protozoans (Oxytricha fallux and Tetrahymena thermophila). The sequence was also repeated in high copy number in a higher plant (Zea mays) as well as at very high levels in a unicellular green alga (Chlamydomonas reinhardi). Although the copy number of the repeat per haploid genome was generally proportional to genome size, there was a greater-than-1,000-fold variation in the number of (TG)25/100-kb genomic DNA. By contrast, no eu-or archaebacterium--including Myxococcus xanthus, whose life cycle is very similar to that of the slime mold Dictyostelium discoideum, and Halobacter volcanii, whose genome contains other repeated sequences-- was found whose genomic DNA contained this sequence in detectable amounts. A computer search also failed to find the TG element in human mitochondrial DNA.      

Ovarian response to PMSG treatment in ewes immunized against oestradiol-17 beta

The effects of active immunization against oestradiol-17 beta on the ovarian response to pregnant mare serum gonadotrophin (PMSG) was investigated in Merino ewes. Immunized (79) and control (41) ewes were synchronized with intravaginal sponges, given either 750 or 1500 i.u. PMSG and then mated to rams or inseminated laparoscopically with fresh diluted semen. All control ewes mated naturally exhibited oestrus and 40 out of 41 control ewes ovulated. The ovulation rate was higher in the controls receiving 1500 i.u. PMSG than in those ewes which received 750 i.u. PMSG (10.2 v. 3.3). Immunization against oestradiol-17 beta resulted in antibody titres varying from 100 to more than 100 000 in plasma taken 1-4 days after mating. The ovarian response increased significantly in the lowest titre group (100-1000) in conjunction with stimulation with 1500 i.u. PMSG. In these ewes the ovulation rate increased over controls (16.7 v. 10.2) as did the total ovarian response, which includes follicles greater than 10 mm diameter (22.3 v. 11.1). The total ovarian response was also increased in those ewes given 750 i.u. PMSG which had titres in the 1000-10 000 and 10 000-100 000 range, but this was not accompanied by significant increases in the ovulation rate. In general, the higher titre levels (greater than 1000) were correlated with decreases in the proportion of ewes showing oestrus and ovulating and in the embryo recovery rate. The 1500 i.u. PMSG treatment group with the highest titres (greater than 10 000) also showed a significant drop in the ovulation rate as compared to the 1500 i.u. PMSG controls.     

Serum oestradiol, progesterone, chorionic gonadotrophin and prolactin concentrations during pregnancy in the Bolivian squirrel monkey (Saimiri sciureus)

Concentrations of chorionic gonadotrophin gradually increased during early pregnancy, reached maximum values at mid-gestation, then declined to low levels. Oestradiol-17 beta concentrations were relatively low (300-600 pg/ml) during early pregnancy, increased thereafter to high levels (10-35 ng/ml), and then appeared to decline towards term. Concentrations of progesterone were constant (100-200 ng/ml) for the first 15 weeks of gestation, suggesting that sequential measurements of progesterone could be used to diagnose early pregnancy. Prolactin concentrations rose during pregnancy, reaching maximum values at term.     

Protein evolution in different cellular environments: cytochrome b in sharks and mammals

DNA sequences for the mitochondrial cytochrome b gene were determined for 13 species of sharks. Rates and patterns of amino acid replacement are compared for sharks and mammals. Absolute rates of cytochrome b evolution are six times slower in sharks than in mammals. Bivariate plots of the number of nonsynonymous and silent transversions are indistinguishable in the two groups, however, suggesting that the differences in amino acid replacement rates are due primarily to differences in DNA substitution rates. Patterns of amino acid replacement are also similar in the two groups. Conserved and variable regions occur in the same parts of the cytochrome b gene, and there is little evidence that the types of amino acid changes are significantly different between the groups. Similarity in the relative rates and patterns of protein change between the two groups prevails despite dramatic differences in the cellular environments of sharks and mammals. Poor penetrance of physiological differences through to rates of protein evolution provides support for the neutral theory and suggests that, for cytochrome b, patterns of evolution have been relatively constant throughout much of vertebrate history.