Play in chimpanzees of the Arnhem Zoo: Self-serving compromises

In a colony of 25 chimpanzees maintained at Arnhem (The Netherlands), play behavior was studied for four months, yielding 1,651 play bouts involving the 11 oldest immature chimpanzees on which detailed data were collected during 88 focal animal samples of 30 min each. Play frequency and object play were negatively correlated with increasing age. These findings potentially reflect changing motivations during development and increasingly perfected skills. Like-aged partners were preferred play partners and older partners initiated play more frequently, probably because younger individuals feared rough responses by older immatures and waited until the latter initiated play bouts in a self-handicapped manner. Moreover, play was frequently interrupted by short breaks. This, in conjunction with the preference for like-aged partners, may be mechanisms to achieve and maintain compromises between the play partners' different interests in social play (which e.g. depend on sex and physical development) and to minimize the risk to being cheated. Males played significantly more often than females and played more chasing games. Male-male play was over-represented whereas female-female play was underrepresented. These facts potentially foreshadow sex differences in (wild) maturing chimpanzees, where males engage in more agonistic conflicts and tend to build coalitions.     

Photoperiodic control of larval development and wing form inModicogryllus sp. (Orthoptera: Gryllidae)

The bivoltine cricket locally known as ‘Tambo-Koorogi’ (Modicogryllus sp.) hibernates as a half-grown larva, and shows a developmental response to changing as well as stationary photoperiod. At 25°C, larvae matured in about 7–10 weeks in continuous or 16 h daily light, but took 10–20 weeks or more in 14 h and shorter days. A day of 15 h exerted an intermediate effect, giving a development time of 7–17 weeks. However, an increase in daylength from 12 to 15 h in the early larval life prevented diapause, while a decrease from 15 to 12 h retarded development more than a constant 12 h day. Short-winged adults occurred only when the photophase was 15 h or shorter, and their frequency increased with decreased daylength. Although the short-winged form took longer to mature than the long-winged form under the same conditions of photoperiod, delayed growth was not always associated with brachypterism.     

Added mass in human swimmers: Age and gender differences

In unstationary swimming (changing velocity), some of the water around the swimmer is set in motion. This can be thought of as an added mass (M_a) of water. The purpose of this study was to find added mass on human swimmers and investigate the effect of shape and body size. Thirty subjects were connected to a 2.8 m long bar with handles, attached with springs (stiffness k=318 N/m) and a force cell. By oscillating this system vertically and registering the period of oscillations it was possible to find the added mass of the swimmer, given the known masses of the bar and swimmer. Relative added mass (M_a%) for boys, women and men were, respectively, 26.8±2.9%, 23.6±1.6% and 26.8±2.3% of the subjects total mass. This study reported significantly lower added mass (p<0.001) and relative added mass (p<0.002) for women compared to men, which indicate that the possible body shape differences between genders may be an important factor for determining added mass. Boys had significantly lower (p<0.001) added mass than men. When added mass was scaled for body size there were no significant differences (p=0.996) between boys and men, which indicated that body size is an important factor that influences added mass. The added mass in this study seems to be lower and within a smaller range than previously reported (Klauck, 1999, Eik et al., 2008). It is concluded that the added mass in human swimmers, in extended gliding position, is approximately 1/4 of the subjects’ body mass.     

Red muscle function in stiff-bodied swimmers: there and almost back again

Fishes with internalized and endothermic red muscles (i.e. tunas and lamnid sharks) are known for a stiff-bodied form of undulatory swimming, based on unique muscle-tendon architecture that limits lateral undulation to the tail region even though the red muscle is shifted anteriorly. A strong convergence between lamnid sharks and tunas in these features suggests that thunniform swimming might be evolutionarily tied to this specialization of red muscle, but recent observations on the common thresher shark (Alopias vulpinus) do not support this view. Here, we review the fundamental features of the locomotor systems in lamnids and tunas, and present data on in vivo muscle function and swimming mechanics in thresher sharks. These results suggest that the presence of endothermic and internalized red muscles alone in a fish does not predict or constrain the swimming mode to be thunniform and, indeed, that the benefits of this type of muscle may vary greatly as a consequence of body size.     

Oviposition site selection in Cactoblastis cactorum (Lepidoptera): constraints and compromises

Summary Oviposition by Cactoblastis cactorum on Opuntia ficus-indica and O. aurantiaca was assessed from the positioning of egg sticks on plants in the field. The number of egg sticks laid on O. ficus-indica plants was affected by: (1) plant size; (2) moth emergence near the plant; (3) cladode condition; and (4) plant conspicuousness. These factors contributed towards the clumping of egg sticks on plants. There was no apparent oviposition preference for one of the two host plant species despite the fact that egg predation was higher and fecundity lower on O. aurantiaca. The selection of a site for oviposition on the host plants was influenced by: (1) cladode condition; (2) height above ground; and (3) shelter from wind during oviposition. Succulent cladodes were the favoured sites for oviposition. The evidence suggests that in C. cactorum, oviposition site selection is largely the net result of a compromise between oviposition behaviour selected for increasing the probability of juvenile survival and oviposition behaviour selected for increasing the probability of laying the full complement of eggs. In addition, environmental and physiological factors such as wind and wing-loading, are thought to place constraints on the range of sites available for oviposition.     

Regulation of damseifly populations: the effects of larval density on larval urvival, development rate and size in the field

SUMMARY. 1. The popuhttion density of Coenagrion pttella larvae was monitored in five populations, and of Ischntira elegans in two populations, between October 1982 and May 1983.
2. There was no measurable mortality of larvae over winter and no larval growth until April. Larvae in high density populations were smaller than those in low density populations and were more likely to have a semi- voltine life history.
3. The population density of C. ptiella was also monitored (more frequently) in two populations with differenl initial densities between July and November 1983. In the high density population there was a constant rate of larval mortality, while in the low density population there was no detectable larval mortality, indicating that larval mortality may be density dependent. Larvae in the high density population were again smaller, and more likely to be semi-voitine, than those in the low density population.
4. The role of density dependent larval growth, development and mortality in the regulation of damseifly populations is discussed.     

Pseudotracheal tubes, larval head, and mycophagy in Sepedophilus (Coleoptera: Staphylinidae: Tachyporinae)

Newton (in: Wheeler, Q.; Blackwell, M. (eds), Fungus-Insect Relationships: Perspectives in Ecology and Evolution . New York: Columbia University Press, pp. 302–353, 1984) characterized five types of Sepedophilus larvae based on head structures and the external and internal features of the head of larvae of Sepedophilus type C are described in detail herein. A functional interpretation of structures involved with feeding is made on the basis of morphological and behavioural observations. Types C and D larvae possess tube-like epipharyngeal structures resembling dipteran labial pseudotrachea, which may play an important role in a specialized liquid-feeding process. Based on a preliminary analysis of head characters delimited by Newton (1984) it is shown that mycophagy has evolved once from a predatory ancestor, although some Sepedophilus groups may have mixed feeding strategies. The epipharyngeal tubes are demonstrated to be unique to mycophagous Sepedophilus in Coleoptera whereas the overall head structure is very similar to mycophagous larvae in the family Sphindidae.     

A case report of cysticercosis caused by Cysticercus longicollis, a larval form of Taenia crassiceps in a woodchuck (Marmota monax)

Cysticercosis was found in one of 18 woodchucks imported from the United States and maintained in our laboratory for study of hepatitis and hepatocellular carcinoma. The lesions found in subcutaneous area, lungs and maxillary sinus were multiple cysts containing numerous cysticerci identified as Cysticercus longicollis, a larval form of Taenia crassiceps.     

Attenuated BMP1 function compromises osteogenesis, leading to bone fragility in humans and zebrafish

Bone morphogenetic protein 1 (BMP1) is an astacin metalloprotease with important cellular functions and diverse substrates, including extracellular-matrix proteins and antagonists of some TGFβ superfamily members. Combining whole-exome sequencing and filtering for homozygous stretches of identified variants, we found a homozygous causative BMP1 mutation, c.34G>C, in a consanguineous family affected by increased bone mineral density and multiple recurrent fractures. The mutation is located within the BMP1 signal peptide and leads to impaired secretion and an alteration in posttranslational modification. We also characterize a zebrafish bone mutant harboring lesions in bmp1a, demonstrating conservation of BMP1 function in osteogenesis across species. Genetic, biochemical, and histological analyses of this mutant and a comparison to a second, similar locus reveal that Bmp1a is critically required for mature-collagen generation, downstream of osteoblast maturation, in bone. We thus define the molecular and cellular bases of BMP1-dependent osteogenesis and show the importance of this protein for bone formation and stability.     

Mystical dreaming: Patterns in form, content, and meaning.

This article enriches the psychological understanding of religious mysticism by exploring patterns of form, content, and meaning in self-described mystical dreams, drawing on extensive sleep and dream interviews conducted with 100 contemporary Americans. Four major hypotheses regarding mystical experience are tested: mysticism as psychopathological, as culturally constructed, as a mode of pure consciousness, and as characterized by four Jamesian “marks” (ineffability, noesis, transience, passivity). The data from this study indicate that mystical dreams are experienced by around half the population and by women more than men, and their prototypical form involves good fortunes, friendly interactions, and unusual or nonhuman characters. These findings provide only limited validation for the psychopathology and pure consciousness hypotheses and somewhat more support for the Jamesian and cultural construction approaches. Taken together, the results suggest that psychological efforts to understand religious mysticism will remain incomplete without systematic reference to contemporary dream research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Toroidal condensates of semiflexible polymers in poor solvents: adsorption, stretching, and compression

When a semiflexible polymer chain is placed in a poor solvent, or in the presence of condensing agents, a toroidal condensate can result. In typical experiments, these condensates are adsorbed to surfaces. Here we examine the changes that can occur when a toroid is adsorbed. We then examine the behavior of a toroid when stretched and identify two regimes: a weak stretching regime where the toroid deforms from a circle to an ellipse, and a strong stretching regime where a tether is pulled from the toroid. In the weak stretching regime, the force increases linearly with separation whereas in the strong stretching regime, the applied force is a constant. We then look at the case of a toroid compressed in the plane of the toroid. In this case the form of the force law depends on how strongly the toroid wets the surfaces. In general, an inverse square force law is found.     

Centrioles and kinetosomes: form, function, and evolution

We review the literature on centrioles, kinetosomes, and other microtubule organizing centers (MTOCs) in animal, plant, and protist cells in the context of the Henneguy-Lenhossék theory of 1899. This 100-year-old cytological theory, valid today, defines centrioles and kinetosomes as identical, homologous but developmentally distinguishable structures. Centrioles (paired constituents of mitotic centrosomes in animal cells) become kinetosomes (ciliary basal bodies) when their 9(2) + 2 microtubular axonemes grow outward. During mitosis in Chlamydomonas, the kinetosomes are segregated at the poles of the mitotic spindle. Mitotic centrioles function as organelles of motility in many protists, though nowhere is this centriole-kinetosome relation more clearly seen than in the karyomastigont structure (kinetosome-nucleus-Golgi complex organellar system) of the trichomonads and other amitochondriate parabasalids. Constituent sequences of mitotic spindle-centriole-kinetosome proteins (gamma-tubulin, pericentrin, and the cyclin-dependent kinases Cdc2 and Cdc3, members of the centrin family) are conserved across taxa, occurring in animal and protist centrioles, plant MTOCs, and fungal spindle pole bodies. We review ultrastructural and molecular data on these and other important MTOC proteins, and present a model whereby the cytological arrangement of centrioles (i.e., orthogonal pairs as in centrosomes) may have originated. We compare and contrast endogenous and exogenous (bacterial symbiont integration) models for the evolution of centriole-kinetosomes (c-ks), with illustrative examples from Kingdom Protoctista.     

Metabolic impairment induces oxidative stress, compromises inflammatory responses, and inactivates a key mitochondrial enzyme in microglia

Microglial activation, oxidative stress, and dysfunctions in mitochondria, including the reduction of cytochrome oxidase activity, have been implicated in neurodegeneration. The current experiments tested the effects of reducing cytochrome oxidase activity on the ability of microglia to respond to inflammatory insults. Inhibition of cytochrome oxidase by azide reduced oxygen consumption and increased reactive oxygen species (ROS) production but did not affect cell viability. Azide also attenuated microglial activation, as measured by nitric oxide (NO.) production in response to lipopolysaccharide (LPS). It is surprising that the inhibition of cytochrome oxidase also diminished the activity of the alpha-ketoglutarate dehydrogenase complex (KGDHC), a Krebs cycle enzyme. This reduction was exaggerated when the azide-treated microglia were also treated with LPS. The combination of the azide-stimulated ROS and LPS-induced NO. would likely cause peroxynitrite formation in microglia. Thus, the possibility that KGDHC was inactivated by peroxynitrite was tested. Peroxynitrite inhibited the activity of isolated KGDHC, nitrated tyrosine residues of all three KGDHC subunits, and reduced immunoreactivity to antibodies against two KGDHC components. Thus, our data suggest that inhibition of the mitochondrial respiratory chain diminishes aerobic energy metabolism, interferes with microglial inflammatory responses, and compromises mitochondrial function, including KGDHC activity, which is vulnerable to NO. and peroxynitrite that result from microglial activation. Thus, activation of metabolically compromised microglia can further diminish their oxidative capacity, creating a deleterious spiral that may contribute to neurodegeneration.