Spatial and temporal patterns of problem polar bears in Churchill,Manitoba

Human–bear interactions near the town of Churchill, Manitoba occur annually because the Western Hudson Bay polar bear population spends 4–5 months on-land each year when the sea ice melts completely. Significant changes have occurred in the Hudson Bay ecosystem and in the bear population as a result of climate warming; however, how these changes may have influenced human–bear interactions near Churchill is unclear. This study examined the temporal and spatial patterns of 1,487 problem bears captured in the Churchill area from 1970 to 2004. We also examined the relationship between problem bears and environmental variables as well as the Nunavut harvest. The number of individual problem bears caught near Churchill varied from 10 to 90 individuals per year and increased over time. Subadult males comprised 39%, subadult females 23%, adult males 18%, females with young 14%, and solitary females 6% of captures. Bears that became problem individuals were in closer proximity to the Churchill area. Nutritional stress and a northward shift in the distribution of the bears that spend the summer on-land in northeastern Manitoba may account for the increase in problem bear numbers. The date of sea ice freeze-up, which is getting progressively later, was the best predictor explaining the annual variation in the occurrence of problem bears. These results provide an understanding of how a warming climate may directly impact polar bear behaviour. This information may allow wildlife managers to predict relative levels of human–bear interactions and thereby implement effective management strategies to improve human safety and the conservation of polar bears.     

Oligomeric protein structure networks: insights into protein-protein interactions

Background  

Protein-protein association is essential for a variety of cellular processes and hence a large number of investigations are being carried out to understand the principles of protein-protein interactions. In this study, oligomeric protein structures are viewed from a network perspective to obtain new insights into protein association. Structure graphs of proteins have been constructed from a non-redundant set of protein oligomer crystal structures by considering amino acid residues as nodes and the edges are based on the strength of the non-covalent interactions between the residues. The analysis of such networks has been carried out in terms of amino acid clusters and hubs (highly connected residues) with special emphasis to protein interfaces.     

Reproduction and growth of the black shore skink,Leiolopisma suteri (Lacertilia: Scincidae), in north‐eastern New Zealand

Reproduction and growth of a boulder beach population of the nocturnal skink Leiolopisma suteri on Motutapu Island were studied for 19 months. Epididymes contain sperm from April to November, and copulation probably occurs in October or November (spring). Ovulation occurs in late October or early November, and three or four (mean, 3.7) eggs are laid in late December. Incubation takes 3 months. Total development time from ovulation to hatching is 5 months, one of the longest development periods recorded for Scincidae. Growth to sexual maturity is slow, most females depositing their first clutch 33 months after hatching; males mature at 29 months.     

Morphogenic Regulation of Pathotoxin Synthesis in Cochliobolus carbonum

The fungus Cochliobolus carbonum causes leaf spot disease of maize. Highly virulent isolates of the pathogen produce a host-selective, peptide toxin that is active against susceptible genotypes of maize. Prior to infection, spores must germinate and differentiate appressoria, structures specialized for leaf penetration. Analysis of spore germination fluids by plasma desorption mass spectrometry, which allowed detection of as little as 0.5 ng toxin, revealed that spores induced to form appressoria in vitro synthesized and released the toxin at a time coincident with maturation of appressoria. Spores incubated under conditions that did not induce appressorium formation failed to produce toxin. These observations indicate that synthesis of the host-selective toxin, which is essential for successful pathogenesis of maize by C. carbonum, is regulated by infection-related morphogenesis.     

Comparative media studies in the isolation ofCandida albicans from pregnant women

Summary Rice agar and corn meal agar, with and without Tween 80, were evaluated clinically as directly inoculable selective and differential media for the isolation ofC. albicans from vulvovaginal specimens taken from pregnant women. Chlamydospore formation on these media was investigated as a criterion for the identification ofC. albicans.Of 301 patients cultured, 118 (39.2 %) gave positive cultures for yeast-like fungi of the genusCandida. Of 118 strains for which fermentation patterns were determined, 69 (58.5 %) gave the pattern forC. albicans. Of these, 56 (81.1 %) formed chlamydospores.Tween 80 was found to exert a very stimulating influence on chlamydospore production. Rice agar with Tween 80 appeared to be the most efficient medium for eliciting chlamydospores. However, since strains of 4 out of 6 species ofCandida isolated were found to sporulate it was concluded that chlamydospore formation is not a reliable criterion for the speciation ofC. albicans.Each of the 4 media served satisfactorily as a directly inoculable selective medium for the isolation of yeast-like fungi of the genusCandida from vulvovaginal specimens. None of the media appeared to preferentially stimulate chlamydospore production inC. albicans.Dr.Smith is Associate Professor in the Department of Microbiology; Dr.Taubert is a Fellow in the Department of Obstetrics and Gynecology; Mr.Towns is Laboratory Assistant in the Department of Microbiology.Supported in part by a grant from the Lederle Medical Faculty Awards Committee and in part by United States Public Health Service Grant E-3068.     

Stakeholders and social networks identify potential roles of communities in sustainable management of invasive species

Identifying stakeholders and analysing the pattern of relationships among them are important steps toward collaborating with individuals and groups for collective action. The process of stakeholders’ communication can be understood by interpreting the structure of the network in which stakeholders operate. Our study attempted to identify stakeholders, determine the structure of their relationships through a social network analysis and examine how network structure could aid collaborative efforts towards invasive species management. We used organizational network analysis, a web-based program, to collect network data for conservation groups on Waiheke Island, New Zealand. Response rate was 47% of the 103 contacts made and thirty-five conservation groups were identified. Results revealed low density, high non-reciprocity, and high centrality among a few stakeholders in the network suggesting a non-cohesive network. We identify how influential stakeholders could carefully initiate and strengthen collaborations that might lead to collective invasive species management action after a thorough examination of mandated, funded or shared interest relationships.     

Ecology of the black shore skink,Leiolopisma suteri (Lacertilia: Scincidae), in boulder beach habitats

The ecology of the nocturnal black shore skink, Leiolopisma suteri, was studied on a boulder beach at Cable Bay, Motutapu Island, for 19 months. Distributions over a stable beach (Motutapu Island) and an exposed beach (Cuvier Island) were compared, and the effects of storms on the Cable Bay population were noted. Density, aggression, thermal preference, feeding, and fat reserve fluctuations were also studied. The L. suteri population at Cable Bay has, in favourable areas, one of the highest densities (13/m²) recorded for a lizard species. Spatial distribution of this population varies between the different age classes: adults congregate in the most stable areas, whereas hatchlings are commonest in the least stable areas. Storms cause changes in the beach structure and in the spatial limits of the population.     

First records of Siphlaenigma janae (Ephemeroptera: Siphlaenigmatidae) from the North Island of New Zealand

Abstract

In the North Island of New Zealand Siphlaenigma janae is common in some forested streams, in slow-flowing areas, on clumps of the alga Bostrychia harveyi forma distans and on overhanging Elatostema rugosum. Nymphs of S. janae are compared with those of the superficially similar siphlonurids Nesameletus spp. and Rallidens mcfarlanei.