Effects of photoperiod, temperature, and host plant age on induction of reproductive diapause and development time in Danaus plexippus

Abstract 1. Diapause induction in monarch butterflies Danaus plexippus was studied using adults captured from the wild in Minnesota and Wisconsin, and individuals reared under outdoor and controlled conditions.
2. Oocyte presence in females and ejaculatory duct mass in males were used to indicate reproductive status.
3. Some wild individuals were in diapause in mid-August, and all males and females were in diapause by late August and early September respectively.
4. Individuals reared under decreasing day lengths and fluctuating temperatures were more likely to be in diapause than were individuals reared under long or short day lengths or constant temperatures.
5. Individuals fed potted old Asclepias curassavica plants were more likely to be in diapause than were those fed potted young host plants; when cuttings of Asclepias syriaca plants from the field or greenhouse pots were used, there was no effect of host plant age.
6. Extremely high temperatures increased the number of day-degrees required for development from egg to adult, while decreasing day lengths and older host plants tended to decrease the number of day-degrees required for development.
7. There appears to be a continuum of reproductive development in monarchs, with gradual declines in mean ejaculatory duct mass and oocyte production during the late summer.
8. None of the experimental treatments led to 100% diapause, and diapause was more likely to occur in monarchs subjected to more than one diapause-inducing cue.     

A personal narrative of particular things: Tevau (feather money) from Santa Cruz,Solomon Islands

In October 2006, Salome Samou, from Santa Cruz Island, Solomon Islands, visited the British Museum, London, to see the collections from her home island. This paper presents her response to the tevau in the collection (frequently referred to as ‘feather money’). Tevau are objects of prestige and value, formerly used in a regional network of exchange. They were especially important in bridewealth payments, but have not been used on Santa Cruz Island since the 1980s. Today, Samou wants to revive their use, a re‐introduction that reflects a linkage of tevau and their manufacture to contemporary ideas of social identity. This paper explores Samou’s interaction with the tevau in the collection, including past interpretations of their use. For Samou, the process of viewing the tevau produced a narrative that embraced personal memories as well as challenged perspectives on past cultural and social practices. I discuss how these particular objects materialise transformed, and transforming, regimes of value.     

Multiple conformations of deoxyribonuclease A. Their separation at alkaline pH and low ionic strength in the presence of Ca2+.

Gel filtration on Sephadex G-100 at pH 9.0 in 1 mM Tris buffer produces denaturation and inactivation of pancreatic DNAase A. Limiting concentrations of Ca2+ in the suspension and elution buffer, reactivates some of the enzyme molecules in an amount proportional to the calcium added. Stable active and inactive forms were separated on Sephadex columns. A model for the conformational role of Ca2+ on DNAase A demonstrates that at least one Ca2+ is involved (Kapp = 8.3 . 10(-5) M) in the correct folding of the polypeptide chain. Na+ was unable to reactivate the enzyme.     

Glycoconjugates of the human trabecular meshwork: a lectin histochemical study

Summary Twelve specimens of resin-embedded human trabecular meshwork were probed with a panel of 21 biotinylated lectins, using an avidin-biotin peroxidase revealing system, in order to determine the normal pattern of saccharide expression in this tissue. High-mannose, intermediate and hybrid N-linked glycans, and complex N-linked bisected and non-bisected bi/tri-antennate glycans, as shown by the binding ofCanavalia ensiformis (ConA),Pisum sativum (PSA),Lens culinaris (LCA) agglutinins andPhaseolus vulgaris erythroagglutinin (ePHA), were strongly expressed by the canal of Schlemm endothelium and juxtacanalicular tissue, but less so by the corneoscleral meshwork. Highly branched complex glycans were not found, as there was no binding byPhaseolus vulgaris leukoagglutinin (1PHA). Sialyl residues, especially thoseα2,6-linked as demonstrated by strongSambucus nigra (SNA) lectin staining, were also abundant in this area.N-acetyllactosamine sequences and some O-linked glycans were present in the trabecular meshwork, as shown bySolanum tuberosum (STA),Datura stramonium (DSA), andJacalin (Jac) lectin binding, while fucose residues were not detected byTetragonolobus purpureas (LTA) orUlex europaeus-1 (UEA-1) agglutinins. These results indicate similarities with renal glomerular and vascular endothelium, although the lack of binding with UEA-1 agglutinin suggests differences which may relate to the specialized function of the trabecular meshwork. This study provides a baseline for comparative analysis of the glycans of human trabecular meshwork in pathological conditions such as primary open-angle glaucoma.     

Knowledge-based models for predicting species occurrence in arable conditions

This paper explores the potential of rule-based habitat models to predict the occurrence of some common species in arable conditions. Models were developed for 10 arable plant species, 7 Hemiptera species, 8 carabid species and for 5 bird species whose ecology was sufficiently known. Rule sets linking species occurrence to environmental variables were produced using available literature and expert knowledge about ecological requirements of the selected species. Environmental variables described the nature and condition of habitats at various scales, ranging from vegetation quadrat to the landscape in a 1 km radius of species sampling sites. The performance of the 34 models developed was assessed in two areas of England. Results show the rule-based habitat models developed for arable plants and birds were not very successful with Cohen's k values often <0.4 for plants and very close to 0 for all bird species. Conversely, rule-based models performed surprisingly well for carabids and Hemiptera with k values on average >0.4. This suggests that ecological knowledge on these invertebrate species is more complete than we expected. The effect of species prevalence on model performance and the potential application of knowledge-based habitat models in the context of biodiversity assessment are discussed.     

Evaluation of comparative protein modeling by MODELLER

We evaluate 3D models of human nucleoside diphosphate kinase, mouse cellular retinoic acid binding protein I, and human eosinophil neurotoxin that were calculated by MODELLER , a program for comparative protein modeling by satisfaction of spatial restraints. The models have good stereochemistry and are at least as similar to the crystallographic structures as the closest template structures. The largest errors occur in the regions that were not aligned correctly or where the template structures are not similar to the correct structure. These regions correspond predominantly to exposed loops, insertions of any length, and non-conserved side chains. When a template structure with more than 40% sequence identity to the target protein is available, the model is likely to have about 90% of the mainchain atoms modeled with an rms deviation from the X-ray structure of ≈ 1 Å, in large part because the templates are likely to be that similar to the X-ray structure of the target. This rms deviation is comparable to the overall differences between refined NMR and X-ray crystallography structures of the same protein. © 1995 Wiley-Liss, Inc.