Behavioral laterality in captive bonobos (Pan paniscus): Replication and extension

We report observational data on behavioral laterality in 10 captive bonobos (Pan paniscus)at the San Diego Zoo. The unimanual measures include carrying, leading limb in locomotion, self-touching, face-touching, reaching, and gestures. We also recorded bimanual feeding in these subjects. A significant population level left-hand bias exists for carrying. Right-hand biases occur for leading limb in locomotion and gestures. During bimanual feeding, the bonobos hold food items with the left hand while feeding with the right hand. Overall, bonobos exhibit behavioral asymmetries that are similar to previous findings in other pongid ape species. The asymmetries in gestures and bimanual feeding represent novel findings with theoretical implications for the origins of tool use and language.     

Dissection of the effector-binding site and complementation studies of Escherichia coli phosphofructokinase using site-directed mutagenesis

A systematic study by site-directed mutagenesis has been conducted on the effector site of phosphofructokinase from Escherichia coli to delineate the role of side chains in binding the allosteric activator, GDP, and inhibitor, PEP, and to search for key residues in the allosteric transtion. Target residues were identified from the crystal structure of the enzyme-nucleoside diphosphate complex. It is found that both activator and inhibitor bind to the same set of amino acid side chains. Deletion of positively charged groups (Arg21, Arg25, Arg54, Arg154, and Lys213 mutated to alanine) weakens binding of both effectors by 2-3 kcal/mol, consistent with the disruption of charged hydrogen bonds. Residue Glu187, which is known from the crystal structure to bind the coordinated Mg2+ ion of GDP, is found to have a unique behavior on mutation and appears to be crucial in triggering the allosteric transition. All other residues mutated simply weaken binding of both PEP and GDP in a parallel manner. However, mutation of Glu----Ala187 reverses the roles of GDP and PEP, causing GDP to become an allosteric inhibitor and PEP an activator. Mutation of Glu----Gln187 has only a small effect on the binding of PEP, and both PEP and GDP are inhibitors. Studies are described in which mutations in different subunits of a tetrameric complex complement each other. The effector site is composed of residues from two subunits. In particular, Arg21 and Lys213 in each site are from different subunits. Mutations of either one of these residues abolishes activation by GDP of the homotetramer.(ABSTRACT TRUNCATED AT 250 WORDS)     

THE PRIMARY ROOT EPIDERMIS OF PANICUM VIRGATUM L. I. ONTOGENY AND FINE STRUCTURE OF THE EPIDERMAL CYTOPLASMIC INCLUSIONS

The ontogeny of large, globular, epidermal cytoplasmic inclusions (ECI) in P. virgatum roots was studied at the ultrastructural level. These ECI were seen to originate in meristematic cells as small electron translucent vesicles. Subsequently, the ECI, which appeared to be temporary storage sites, were seen to enlarge and increase in density by accumulating masses of a granular matrix as well as some small vesicular inclusions. In the zone of elongation, as the epidermal cells matured, the ECI within each cell gradually fused and the contents were lost. The pattern of the ontogeny of the ECI in the growing epidermal cells was consistent with the presence of cells of different physiologies in the zone of cell elongation of these roots.     

PYCNOGENOL chewing gum minimizes gingival bleeding and plaque formation.

PYCNOGENOL is an antioxidant phytochemical shown to have antiinflammatory activity in both the in vitro and in vivo models. This study compared the effects of chewing gums with and without PYCNOGENOL on gingival bleeding and plaque formation in 40 human subjects. In this double-blind study, subjects were assigned randomly to receive either control gums without PYCNOGENOL or experimental gums containng 5 mg PYCNOGENOL. Subjects used chewing gums for 14 days. Gingival bleeding and plaque scores were taken before and after the experiment. PYCNOGENOL chewing gums significantly reduced gingival bleeding, while no changes were noted in bleeding indexes in control subjects who used regular chewing gums. Subjects using regular control gums had significant increases of dental plaque accumulation during the two-week period. No increases in plaque accumulation were noted in subjects using PYCNOGENOL chewing gums. The data of this study suggest that the use of Pycnogenol chewing gums can minimize gingival bleeding and plaque accumulation.     

Why Doesn't the Creed Read "Always Be Critical"? An Examination of a Liberal Curriculum

Using ethnographic data collected in a second grade classroom over the course of a school year, this paper describes the ways in which one school's discourse of liberalism is deleteriously deployed. We view the school's discipline creed as emblematic of the school's liberal curriculum, and interrogate the effects on four African American boys in the classroom when the school enacts this creed. Despite the agency that these boys obviously had, they were unable to control the ways in which they were placed at a structural disadvantage and manipulated by a system far more powerful than they were. The results were that these four boys suffered. Not only did the intended liberal curriculum fail to be translated fully into the enacted curriculum, the liberal underpinnings of this curriculum precluded teachers and students from taking any critical stance.     

Parasitoid behaviour: predicting field from laboratory

Abstract.  1. Most of what is known about parasitoid behaviour comes from laboratory observations: field quantitative observations on searching parasitoids are extremely difficult to do and are rare. The basic components of Aphytis melinus 's response to California red scale ( Aonidiella aurantii ) were studied in the laboratory: encounter, rejection, drumming, probing, oviposition, and host-feeding. It was then asked whether these observations provided a reliable guide to behaviour in the field in a situation that was very different from the laboratory.
2. Field observations were carried out on bark on the trunk and interior branches of trees where live scale density is extremely high in patches, dead scale make up 90% of all scale, and could be expected to interfere with Aphytis search.
3. The laboratory observations predicted well the time taken in the field for each basic event (drumming or probing) and average times spent on a scale. Also well predicted were the distributions of times spent on drumming, probing, and total time on a scale. Rejection rates were much higher in the field. Thus, the laboratory studies predicted foraging behaviour in the field with variable success; potential explanations for observed mismatch between laboratory and field and its possible larger implications are discussed.