Loss of Potential Aquatic-Terrestrial Subsidies Along the Missouri River Floodplain

The floodplains of large rivers have been heavily modified due to riparian development and channel modifications, both of which can eliminate shallow off-channel habitats. The importance of these habitats for aquatic organisms like fishes is well studied. However, loss of off-channel habitat also eliminates habitats for the production of emerging aquatic insects, which subsidize riparian consumers in terrestrial food webs. We used field collections of insect emergence, historical mapping, and statistical modeling to estimate the loss of insect emergence due to channel modifications along eight segments of the Missouri River (USA), encompassing 1566 river km, between 1890 and 2012. We estimate annual production of emerging aquatic insects declined by a median of 36,000 kgC (95% CrI: 3000 to 450,000) between 1890 and 2012 (a 34% loss), due to the loss of surface area in backwaters and related off-channel habitats. Under a conservative assumption that riparian birds obtain 24% of their annual energy budget from adult aquatic insects, this amount of insect loss would be enough to subsidize approximately 790,000 riparan woodland birds during the breeding and nesting period (May to August; 95% CrI: 57,000 to 10,000,000). Most of the loss is concentrated in the lower reaches of the Missouri River, which historically had a wide floodplain, a meandering channel, and a high density of off-channel habitats, but which were substantially reduced due to channelization and bank stabilization. Our results indicate that the loss of off-channel habitats in large river floodplains has the potential to substantially affect energy availability for riparian insectivores, further demonstrating the importance of maintaining and restoring these habitats for linked aquatic-terrestrial ecosystems

Post-imperialism, postcolonialism and beyond: towards a periodisation of cultural discourse about colonial legacies

Taking German history and culture as a starting point, this essay suggests a historical approach to reconceptualising different forms of literary engagement with colonial discourse, colonial legacies and (post-) colonial memory in the context of Comparative Postcolonial Studies. The deliberate blending of a historical, a conceptual and a political understanding of the ‘postcolonial’ in postcolonial scholarship raises problems of periodisation and historical terminology when, for example, anti-colonial discourse from the colonial period or colonialist discourse in Weimar Germany are labelled ‘postcolonial’. The colonial revisionism of Germany’s interwar period is more usefully classed as post-imperial, as are particular strands of retrospective engagement with colonial history and legacy in British, French and other European literatures and cultures after 1945. At the same time, some recent developments in Francophone, Anglophone and German literature, e.g. Afropolitan writing, move beyond defining features of postcolonial discourse and raise the question of the post-postcolonial

Loss of Potential Aquatic-Terrestrial Subsidies Along the Missouri River Floodplain

The floodplains of large rivers have been heavily modified due to riparian development and channel modifications, both of which can eliminate shallow off-channel habitats. The importance of these habitats for aquatic organisms like fishes is well studied. However, loss of off-channel habitat also eliminates habitats for the production of emerging aquatic insects, which subsidize riparian consumers in terrestrial food webs. We used field collections of insect emergence, historical mapping, and statistical modeling to estimate the loss of insect emergence due to channel modifications along eight segments of the Missouri River (USA), encompassing 1566 river km, between 1890 and 2012. We estimate annual production of emerging aquatic insects declined by a median of 36,000 kgC (95% CrI: 3000 to 450,000) between 1890 and 2012 (a 34% loss), due to the loss of surface area in backwaters and related off-channel habitats. Under a conservative assumption that riparian birds obtain 24% of their annual energy budget from adult aquatic insects, this amount of insect loss would be enough to subsidize approximately 790,000 riparan woodland birds during the breeding and nesting period (May to August; 95% CrI: 57,000 to 10,000,000). Most of the loss is concentrated in the lower reaches of the Missouri River, which historically had a wide floodplain, a meandering channel, and a high density of off-channel habitats, but which were substantially reduced due to channelization and bank stabilization. Our results indicate that the loss of off-channel habitats in large river floodplains has the potential to substantially affect energy availability for riparian insectivores, further demonstrating the importance of maintaining and restoring these habitats for linked aquatic-terrestrial ecosystems

Aging affects response to cyclic tensile stretch: paradigm for intervertebral disc degeneration

Much evidence supports a fundamental role for mechanical forces in modulating differentiation, homeostasis, and remodelling of musculoskeletal cells. Little is known, however, regarding mechanobiology and gene expression of intervertebral disc (IVD) cells from older individuals. To characterise the effect of mechanical stimulation on cells from older discs, an in vitro study of IVD cells harvested from different aged pigs was conducted to measure extracellular matrix (ECM) gene expression in response to cyclic tensile stress (CTS). Gene expression of annulus fibrosus (AF) cells from IVDs of mature and older pigs was quantified for the predominant ECM genes; type I collagen, type II collagen and aggrecan, and matrix metalloproteinase 1 (MMP-1), a collagenase that degrades fibrillar collagens.AF cells cultured on flexible-bottom plates were stretched 10 % at 0.5 Hz frequency. After 24 h, gene expression was assayed using reverse transcriptase polymerase chain reaction (RT-PCR). Basal mRNA levels without stretching for type II collagen and aggrecan were lower in older annular cells whereas MMP-1 levels were higher compared to mature cells. Following CTS, an adaptive response was elicited in annular cells from both age groups. ECM protein genes were upregulated, whereas MMP-1 was downregulated. The magnitude of response was significantly greater in older cells as compared to mature cells. These data suggest that the cells from the AF of older animals manifest lower basal levels of mRNA for type II collagen and aggrecan and higher levels of MMP-1 possibly due to decreased tensile stress experienced in vivo and is not the result of reduced capacity for response

Dermatophagoides pteronyssinus Major Allergen 1 Activates the Innate Immune Response of the Fruit Fly Drosophila melanogaster

Some allergens with relevant protease activity have the potential to directly interact with host structures. It remains to be elucidated whether this activity is relevant for developing their allergenic properties. The major goal of this study was to elucidate whether allergens with a strong protease activity directly interact with modules of the innate immune system, thereby inducing an immune response. We chose Drosophila melanogaster for our experiments to prevent the results from being influenced by the adaptive immune system and used the armamentarium of methods available for the fly to study the underlying mechanisms. We show that Dermatophagoides pteronyssinus major allergen 1 (Der p 1), the major allergen of the house dust mite, efficiently activates various facets of the Drosophila innate-immune system, including both epithelial and systemic responses. These responses depend on the immune deficiency (IMD) pathway via activation of the NF-κB transcription factor Relish. In addition, the major pathogen associated molecular pattern recognizing receptor of the IMD pathway, peptidoglycan recognition protein-LC, was necessary for this response. We showed that Der p 1, which has cysteine protease activity, cleaves the ectodomain of peptidoglycan recognition protein-LC and, thus, activates the IMD pathway to induce a profound immune response. We conclude that the innate immune response to this allergen-mediated proteolytic cleavage represents an ancient type of danger signaling that may be highly relevant for the primary allergenicity of compounds such as Der p 1