The onchocerciasis chronicle: from the beginning to the end?

The year 2012 marks the 25th anniversary of the donation of ivermectin to fight onchocerciasis and the projected date for elimination of transmission of the disease in the Americas. This review looks at the history of onchocerciasis, from its discovery through to 2025, by which time it is projected that the disease will have been eliminated as a public health problem, except in a handful of sub-Saharan countries, where it should be well on the way towards elimination.     

Anti-bacterial monoclonal antibodies: Back to the future?

Today's medicine has to deal with the emergence of multi-drug resistant bacteria, and is beginning to be confronted with pan-resistant microbes. This worsening inadequacy of the antibiotics concept, which has ruled infectious medicine in the last six decades creates an increasing unmet medical need that can be addressed by passive immunization. While past experience from the pre-antibiotic era with serum therapy was in many cases encouraging, antibacterial monoclonal antibodies have so far suffered high attrition rates in the clinic, generally from lack of efficacy. Yet, we believe that recent developments in a number of areas such as infectious disease pathogenesis research, translational medicine, mAb engineering, mAb manufacturing and rapid bedside diagnostics are converging to make the medium-term future permissive for antibacterial mAb development. Here, we review antibacterial mAb-based approaches that are or were in clinical development, and may potentially act as paradigms with regards to molecular targets, antibody formats and mode-of-action, pre-clinical validation and selection of most relevant patient populations, in order to increase the likelihood of successful product development in this field.     

Is the Species Flock Concept Operational? The Antarctic Shelf Case

There has been a significant body of literature on species flock definition but not so much about practical means to appraise them. We here apply the five criteria of Eastman and McCune for detecting species flocks in four taxonomic components of the benthic fauna of the Antarctic shelf: teleost fishes, crinoids (feather stars), echinoids (sea urchins) and crustacean arthropods. Practical limitations led us to prioritize the three historical criteria (endemicity, monophyly, species richness) over the two ecological ones (ecological diversity and habitat dominance). We propose a new protocol which includes an iterative fine-tuning of the monophyly and endemicity criteria in order to discover unsuspected flocks. As a result nine « full » species flocks (fulfilling the five criteria) are briefly described. Eight other flocks fit the three historical criteria but need to be further investigated from the ecological point of view (here called « core flocks »). The approach also shows that some candidate taxonomic components are no species flocks at all. The present study contradicts the paradigm that marine species flocks are rare. The hypothesis according to which the Antarctic shelf acts as a species flocks generator is supported, and the approach indicates paths for further ecological studies and may serve as a starting point to investigate the processes leading to flock-like patterning of biodiversity.     

Species concepts for trypanosomes: from morphological to molecular definitions?

The way species and subspecies names are applied in African trypanosomes of subgenera Trypanozoon and Nannomonas is reviewed in the light of data from molecular taxonomy. In subgenus Trypanozoon the taxonomic importance of pathogenicity, host range and distribution appear to have been inflated relative to actual levels of genetic divergence. The opposite is true for subgenus Nannomonas, where current taxonomic usage badly underrepresents genetic diversity. Data from molecular characterisation studies are revealing a growing number of genotypes, which may represent distinct taxa. Unfortunately few of these genotypes are yet supported by sufficient biological data to be recognized taxonomically. But we may be missing fundamental epidemiological information, because of our inability to distinguish these trypanosomes in host blood morphologically or in tsetse by their developmental cycle. Molecular taxonomy has led the way in identifying these new genotypes and now offers the key to elucidating the biology of these organisms.     

The Protector Species Hypothesis: Do Black Skimmers Find Refuge from Predators in Gull-billed Tern Colonies?

The protector-species hypothesis explains mixed-species coloniality on the basis of benefits individuals of a species may receive by nesting with another species, the ‘protector’ species, that responds aggressively to potential threats. The reactions of nesting individuals to both natural and model predators were observed to determine whether black skimmers (Rhynchops niger) gain an antipredator advantage by nesting with gull-billed terns (Sterna nilotica). Observations of natural predators were gathered from three mixed-species and three single-species (black skimmers) subcolonies. Natural predators most commonly encountered by the colonies were herring gulls (Larus argentatus), laughing gulls (Larus atricilla), and ruddy turnstones (Arenaria interpres). Gull-billed terns responded to the gulls, but not to the turnstones, in higher proportions than did black skimmers. Two decoys, a mink and a gull, were used to simulate predatory encounters, and a duck decoy was used as a control at two mixed-species and one single-species subcolonies. Gull-billed terns responded in significantly higher proportions than did skimmers to all decoy treatments in the mixed-species subcolonies. Mobbing of both natural and model predators by the terns suggests that skimmers may gain a reproductive advantage by nesting with these terns. However, the response of black skimmers to both natural and simulated predators was independent of the presence of gull-billed terns in the colony, indicating that black skimmers may not perceive these objects as threats, or may react differently to predators than do gull-billed terns.     

The World's Most Isolated and Distinct Whale Population? Humpback Whales of the Arabian Sea

A clear understanding of population structure is essential for assessing conservation status and implementing management strategies. A small, non-migratory population of humpback whales in the Arabian Sea is classified as “Endangered” on the IUCN Red List of Threatened Species, an assessment constrained by a lack of data, including limited understanding of its relationship to other populations. We analysed 11 microsatellite markers and mitochondrial DNA sequences extracted from 67 Arabian Sea humpback whale tissue samples and compared them to equivalent datasets from the Southern Hemisphere and North Pacific. Results show that the Arabian Sea population is highly distinct; estimates of gene flow and divergence times suggest a Southern Indian Ocean origin but indicate that it has been isolated for approximately 70,000 years, remarkable for a species that is typically highly migratory. Genetic diversity values are significantly lower than those obtained for Southern Hemisphere populations and signatures of ancient and recent genetic bottlenecks were identified. Our findings suggest this is the world''s most isolated humpback whale population, which, when combined with low population abundance estimates and anthropogenic threats, raises concern for its survival. We recommend an amendment of the status of the population to “Critically Endangered” on the IUCN Red List.     

The Carbohydrate-containing Cell-Wall Polymers of Certain Species from the Cluster “Streptomyces lavendulae”

The type strains of the species of the cluster Streptomyces lavendulae with a low level of DNA–DNA relatedness were found to contain different cell-wall carbohydrate polymers, whereas the species of this cluster with a level of DNA–DNA relatedness of about 60% contain similar or identical carbohydrate polymers. The type strains Streptomyces katraeVKM Ac-1220^Tand S. polychromogenesVKM Ac-1207^Tsynthesize mannan with different amounts of -1,2- and -1,3-substituted mannopyranose units and a small number of 1,3-poly(glycerolphosphate) chains. The cell walls of S. lavendulocolorVKM Ac-215^Tand Streptomycessp. VKM Ac-2117 were found to contain a hitherto unknown teichuronic acid, whose repeating unit is a disaccharide consisting of diaminomannuronic acid and N-acetylgalactosamine: 4)--D-ManpNAc3NAcA-(1 3)--D-GalpNAc-(1 . In addition, the cell walls of these two streptomycetes contain -glucosylated 1,5-poly(ribitol phosphate). The cell walls of S. virginiaeVKM Ac-1218^Tand S. flavotriciniVKM Ac-1277^Tcontain the same poly(glucosyl-glycerolphosphate). The results presented in this paper are in accordance with the DNA–DNA relatedness data and indicate a taxonomic significance of the structure of the cell-wall polysaccharides for the delineation of phenetically related Streptomycesspecies.     

Australia's marine biogeography revisited: Back to the future?

The recognition of broad biogeographic provinces provides an important framework for ecological and conservation biological research. Marine biologists have long recognized distinct biogeographic provinces in southern Australia, primarily on the basis of qualitative differences in intertidal species assemblages. Here we provide an a priori test for these traditional eastern (Peronian), western (Flindersian) and south‐eastern (Maugean) provinces. Specifically, we analyse distributional data for approximately 1500 algal species using the newly available Australian Virtual Herbarium, an online database of herbarium specimens. Our quantitative algal analyses across southern Australia identify three distinct biogeographic assemblages, consistent with traditional qualitative provinces. We argue that these broad provinces provide a highly effective framework for understanding and managing Australia's marine biodiversity. In particular, biogeographic provinces provide a regional framework for integrating the ongoing discovery of biological variation at finer scales. More broadly therefore we recommend that biologists undertake quantitative analyses to test provincial biogeographic boundaries around the globe.     

Evolutionary Biology: How Did the Human Species Form?

A recent analysis has shown that divergence between human and chimpanzee varies greatly across the genome. Although this is consistent with "hybridisation" between the diverging human and chimp lineages, such observations can be explained more simply by the null model of allopatric speciation.     

How did the empire strike back? Lessons for today from The Empire Strikes Back: Race and Racism in 70s' Britain

The Empire Strikes Back made a landmark and sometimes controversial intervention in the scholarship of ethnicity and race when it was first published. This article considers both the continuities and breaks that linked and separated the volume from the Centre for Contemporary Cultural Studies' work and tradition that preceded it. It also suggests that the balance between ethnographic engagement and critical scholarship sets up a necessarily iterative process that values both but also recognizes the differences between the two. Such iteration speaks also to the manner in which the study of contemporary migration and its consequences demands both more self-conscious links between the study of migration and the scholarship of racial formation and ethnic identity.     

The Cape element in the Afrotemperate flora: from Cape to Cairo?

The build-up of biodiversity is the result of immigration and in situ speciation. We investigate these two processes for four lineages (Disa, Irideae p.p., the Pentaschistis clade and Restionaceae) that are widespread in the Afrotemperate flora. These four lineages may be representative of the numerous clades which are species rich in the Cape and also occur in the highlands of tropical Africa. It is as yet unclear in which direction the lineages spread. Three hypotheses have been proposed: (i) a tropical origin with a southward migration towards the Cape, (ii) a Cape origin with a northward migration into tropical Africa, and (iii) vicariance. None of these hypotheses has been thoroughly tested. We reconstruct the historical biogeography of the four lineages using likelihood optimization onto molecular phylogenies. We find that tropical taxa are nested within a predominantly Cape clade. There is unidirectional migration from the Cape into the Drakensberg and from there northwards into tropical Africa. The amount of in situ diversification differs between areas and clades. Dating estimates show that the migration into tropical East Africa has occurred in the last 17 Myr, consistent with the Mio-Pliocene formation of the mountains in this area.     

Does the Order of Invasive Species Removal Matter? The Case of the Eagle and the Pig

Background

Invasive species are recognized as a primary driver of native species endangerment and their removal is often a key component of a conservation strategy. Removing invasive species is not always a straightforward task, however, especially when they interact with other species in complex ways to negatively influence native species. Because unintended consequences may arise if all invasive species cannot be removed simultaneously, the order of their removal is of paramount importance to ecological restoration. In the mid-1990s, three subspecies of the island fox Urocyon littoralis were driven to near extinction on the northern California Channel Islands owing to heightened predation by golden eagles Aquila chrysaetos. Eagles were lured to the islands by an abundant supply of feral pigs Sus scrofa and through the process of apparent competition pigs indirectly facilitated the decline in foxes. As a consequence, both pigs and eagles had to be removed to recover the critically endangered fox. Complete removal of pigs was problematic: removing pigs first could force eagles to concentrate on the remaining foxes, increasing their probability of extinction. Removing eagles first was difficult: eagles are not easily captured and lethal removal was politically distasteful.

Methodology/Principal Findings

Using prey remains collected from eagle nests both before and after the eradication of pigs, we show that one pair of eagles that eluded capture did indeed focus more on foxes. These results support the premise that if the threat of eagle predation had not been mitigated prior to pig removal, fox extinction would have been a more likely outcome.

Conclusions/Significance

If complete eradication of all interacting invasive species is not possible, the order in which they are removed requires careful consideration. If overlooked, unexpected consequences may result that could impede restoration.     

Conquered from the Deep Sea? A New Deep-Sea Isopod Species from the Antarctic Shelf Shows Pattern of Recent Colonization

The Amundsen Sea, Antarctica, is amongst the most rapidly changing environments of the world. Its benthic inhabitants are barely known and the BIOPEARL 2 project was one of the first to biologically explore this region. Collected during this expedition, Macrostylis roaldi sp. nov. is described as the first isopod discovered on the Amundsen-Sea shelf. Amongst many characteristic features, the most obvious characters unique for M. roaldi are the rather short pleotelson and short operculum as well as the trapezoid shape of the pleotelson in adult males. We used DNA barcodes (COI) and additional mitochondrial markers (12S, 16S) to reciprocally illuminate morphological results and nucleotide variability. In contrast to many other deep-sea isopods, this species is common and shows a wide distribution. Its range spreads from Pine Island Bay at inner shelf right to the shelf break and across 1,000 m bathymetrically. Its gene pool is homogenized across space and depth. This is indicative for a genetic bottleneck or a recent colonization history. Our results suggest further that migratory or dispersal capabilities of some species of brooding macrobenthos have been underestimated. This might be relevant for the species’ potential to cope with effects of climate change. To determine where this species could have survived the last glacial period, alternative refuge possibilities are discussed.     

The “Egg of Columbus” for Making the World's Toughest Fibres

In this letter we present the “Egg of Columbus” for making fibres with unprecedented toughness: a slider, in the simplest form just a knot, is introduced as frictional element to dissipate additional energy and thus demonstrating the existence of a previously “hidden” toughness. The proof of concept is experimentally realized making the world''s toughest fibre, increasing the toughness modulus of a commercial Endumax macroscopic fibre from 44 J/g up to 1070 J/g (and of a zylon microfiber from 20 J/g up to 1400 J/g). The ideal upperbound toughness is expected for graphene, with a theoretical value of ∼10⁵ J/g. This new concept, able of maximizing (one fold increment) the structural robustness, could explain the mysterious abundance of knot formations, in spite of their incremental energy cost and topological difficulty, in biological evolved structures, such as DNA strands and proteins.