Ligand and pathogen specificity of the Atlantic salmon serum C-type lectin

Background

An Atlantic salmon (Salmo salar) C-type lectin (SSL) binds to mannose and related sugars as well as to the surface of Aeromonas salmonicida. To characterize this lectin as a pathogen recognition receptor in salmon, aspects of its interaction with molecules and with intact pathogens were investigated.

Methods

SSL was isolated using whole-yeast-affinity and mannan-affinity chromatography. The binding of SSL to the two major surface molecules of A. salmonicida, lipopolysaccharide (LPS) and A-layer protein was investigated by western blotting and enzyme-linked immunosorbent assays. Microbial binding specificity of SSL was examined by whole cell binding assays using a range of species. Carbohydrate ligand specificity of SSL was examined using glycan array analysis and frontal affinity chromatography.

Results

SSL showed binding to bacteria and yeast including, Pseudomonas fluorescens, A. salmonicida, A. hydrophila, Pichia pastoris, and Saccharomyces cerevisiae, but there was no detectable binding to Yersinia ruckeri. In antimicrobial assays, SSL showed no activity against Escherichia coli, Bacillus subtilis, S. cerevisiae, or A. salmonicida, but it was found to agglutinate E. coli. The major surface molecule of A. salmonicida recognized by SSL was shown to be LPS and not the A-layer protein. LPS binding was mannose-inhibitable. Glycans containing N-acetylglucosamine were shown to be predominant ligands.

Conclusion

SSL has a distinct ligand preference while allowing recognition of a wide variety of related carbohydrate structures.

General Significance

SSL is likely to function as a wide-spectrum pattern recognition protein.     

The effects of predator removal on mallard production and population change in northeastern North Dakota

In 1994, Delta Waterfowl Foundation began trapping mammalian meso-predators in North Dakota during the breeding season in an attempt to increase waterfowl nest success and enhance recruitment into the fall flight and subsequent breeding population. Multiple studies on these sites demonstrated that removing predators results in near doubling of nest success, which previous simulation modeling suggests is the most influential vital rate influencing the population growth rate of mid-continent mallards (Anas platyrhynchos). We present an assessment of the impact of predator removal on mallard production using population models. We conducted this study on 9 township-sized (93.2 km²) sites (4–8 sites annually per vital rate) in northeastern North Dakota from 2006–2008. Trappers removed mammalian meso-predators on 5 sites and the other 4 served as unmanaged reference sites. To estimate recruitment, we used derived estimates and process variance of pair numbers, hen success (nest survival corrected for renesting), initial brood size, pre-fledging survival, and post-fledging survival, along with previously published estimates of breeding propensity and adult female survival rates. Trapped sites had greater hen success (H = 0.69, = 0.03) than reference sites (H = 0.53, = 0.06), but similar indicated breeding pairs, initial brood size, and pre-fledging survival. We estimated that females on trapped sites added 140 more mallards of both sexes to the fall flight than females on reference sites, at an approximate cost of $74.29 per incremental mallard. Additionally, trapping predators provided a marginal increase (0.04) in finite population growth. We found that predator removal targeted at mammalian nest predators did not produce as many incremental mallards as previously thought and may not be a viable strategy for increasing mallard productivity under conditions similar to those observed during this study. We conducted a sensitivity analysis and determined that pre-fledging survival was the most influential factor regulating mallard population growth. Although hen success increased as a result of trapping, duckling survival became a limiting factor. We suggest that waterfowl managers assess multiple vital rates to determine the likelihood that management actions focused on a single parameter, such as nest success, will yield desired population level effects. © 2012 The Wildlife Society.     

The first checklist of black fungus gnats (Diptera: Sciaridae) of Morocco

The first checklist of black fungus gnats is established; new faunistic records of Sciaridae are presented, providing a list of 10 genera and 55 species. Forty-eight species are newly listed for Morocco, increasing the total of Sciaridae known from Morocco to 69 species, belonging to 12 genera, of which six (Austrosciara Schmitz & Mjöberg, 1924, Bradysiopsis Tuomikoski, 1960, Epidapus Haliday, 1851, Lycoriella Frey, 1942, Pseudolycoriella Menzel & Mohrig, 1998 and Sciara Meigen, 1803) are newly reported for Moroccan fauna.     

Le genre Cratopus aux îles Seychelles (Coleoptera : Curculionidae)

Les espèces seychelloises du genre Cratopus Schoenherr 1823 sont révisées, et quatre nouveaux taxons sont décrits. Espèce de grande taille (16–19 mm), C. roberti n. sp. possède dix stries élytrales, des fémurs antérieurs portant de petits denticules, y compris sur la dent, et un revêtement squamuleux vert métallique, avec une bande blanche le long de la base et des côtés des élytres, ainsi que sur les côtés du prothorax. Long de 8–10 mm, C. venustus n. sp. se reconnait à ses téguments noirs et brillants, sa vestiture réduite bleu-vert métallique, ses douze stries élytrales de forts points, ainsi qu’à ses interstries 8 et 9 caréniformes. C. griseovestitus northislandensis n. ssp. diffère de la forme nominative C. griseovestitus griseovestitus Linell 1887 par ses téguments coriacés et sa vestiture métallique du dessus dense, à reflets cuivre doré ou verts, et non gris blanchâtre ou bleuâtre. C. griseovestitus fregata n. ssp. diffère de son côté de la forme nominative par ses téguments bruns plus ou moins foncés, saupoudrés de poils et de squamules très petits. Les synonymies de C. parcesquamosus Fairmaire 1893 et de C. abbotti Linell 1907 avec C. aurostriatus Fairmaire 1892 sont confirmées, et enfin un tableau de détermination des espèces seychelloises du genre est donné. Les Cratopus des Seychelles se divisent en un ensemble de trois espèces du groupe de griseovestitus, à large répartition, habitant les côtes et les îles coralliennes basses et probablement d’arrivée récente, et un ensemble de six espèces limitées aux îles granitiques, où cinq d’entre elles ont une distribution limitée à l’intérieur d’une île ou deux. Elles sont certainement de souche beaucoup plus ancienne. Les Cratopus des Seychelles sont folivores à l’état adulte, et souvent polyphages. Une liste de leurs plantes-hôtes connues est donnée.     

Revision of the genus Evanos Laporte de Castelnau, 1840, with the description of a second species (Coleoptera: Scarabaeoidea: Rutelidae: Geniatini)

The monotypic genus Evanos (Coleoptera: Rutelidae: Geniatini) is revised and a new species, E. danieleae Grossi, n. sp., is described based on specimens collected from Minas Gerais, Brazil. A lectotype is designated for Evanos villatus. Diagnostic characters and comments about the taxonomic status of the genus are given, as well as a key for both species and a distribution map with the known locality records.     

‘A genealogist's paradise’: France,Québec and the genealogics of race

Genealogy, or the study of one's ancestral patri-lineage, has a long and esteemed pedigree in French Canadian and Québécois history. From Cyprien Tanguay's late-nineteenth-century encyclopedias to René Jetté's updated versions more than a century later, genealogy has been an important component of French Canadian nationalisms. Tracing one's ancestry back to the early St. Lawrence settlement in the seventeenth century has provided Québécois subjects with opportune political and social capital with which to make territorial and national claims legitimate. Through a case study approach, I explain how genealogy provides the grounds upon which Québécois and French subjects remember a shared past. Specifically, I examine a variety of sites of memory in the French countryside, including a museum that relies on ‘genealogics’ to call the French Canadian Québécois back to its roots. As such, I demonstrate how the biological, read as a contemporary articulation of Balibar's notion of the racial supplément necessary to nation building, travels across the Atlantic.     

The minority culture of mobility of France's upwardly mobile descendants of North African immigrants

This article examines the challenges associated with the experience of upward educational mobility among descendants of North African immigrants in France. Drawing on in-depth, open-ended interviews with students and graduates of the prestigious grandes écoles, it sheds light on three specific ways in which class-based and ethno-racial inequalities intersect to shape the mobility costs that our respondents outline: (1) feelings of isolation resulting from being one of the only bursar recipients and ethno-racial minorities of their schools; (2) perceived conflation of their minority background with counter-elite dispositions; and (3) difficulties of adjusting to a student life reflecting the cultural styles of the predominantly white, upper-middle-class group. The article suggests that our respondents deploy a minority culture of mobility rooted in class and ethno-racial processes to overcome these challenges. It finally discusses implications for future research, stressing the need to examine the intersecting effect of multiple social categories in informing complex mobility experiences.     

Particular universalisms: North African immigrants respond to French racism

This article examines how ordinary victims of racism rebut racist beliefs communicated to them by the mass media and encountered in daily life. We describe the rhetorical devices that North African immigrant men in France use to respond to French racism, drawing on thirty in-depth interviews conducted with randomly selected blue-collar immigrants residing in the Paris suburbs. We argue that while French anti-racist rhetorics, both elite and popular, draw on universalistic principles informed by the Enlightenment as well as French Republican ideals, North African immigrants rebut racism by drawing instead on their daily experience and on a 'particular universalism', i.e. a moral universalism informed by Islam. Their arguments frequently centre on claims of equality or similarity between all human beings, or between North Africans and the French. Available cultural repertoires and the structural positions of immigrants help to account for the rhetorical devices that immigrants use to rebut racism.