Fish passage design for sustainable hydropower in the temperate Southern Hemisphere: an evidence review

The development of hydropower and other infrastructure that disrupts river connectivity poses a serious threat to highly endemic and genetically distinct freshwater fish species in temperate parts of the Southern Hemisphere. Such locations have been neglected in previous reviews on fish passage. Fishways have long been constructed to mitigate the impacts of riverine barriers on fish, yet they have often failed for all but the largest, strongest swimming taxa. This is a particular problem in the temperate south, which is home to native species that are non-recreational and generally small-bodied with weak swimming abilities (e.g. Galaxiidae) relative to typical target species for fishway design (e.g. Salmonidae). Using the Eco Evidence method for rapid evidence synthesis, we undertook an assessment of evidence for effective fishway design focusing on species representative of the temperate south, including eel and lamprey. Systematic literature searches resulted in 630 publications. Through a rigorous screening process these were reduced to 46 publications containing 76 evidence items across 19 hypotheses relating to design criteria for upstream and downstream passage. We found an overwhelming lack of evidence for effective fishway design in the temperate south. Particular deficiencies were found with regard to the design of effective facilities for downstream passage. The attraction and entrance of upstream migrating fish into fishways is also relatively under-researched. Given the urgent need for effective fishways in the temperate south, these results justify an approach to fishway design based on a combination of empirical data and expert knowledge. In the meantime, significant resources should be assigned to improve the evidence base through high quality research. The particular deficiencies identified here could guide that research agenda.     

Evidence for diet partitioning among three coexisting native freshwater fishes in South Africa's Cape Fold Ecoregion

The partitioning of limited resources commonly explains how different species can coexist within the same ecological community. In this 2010 study, the diets of three coexisting freshwater fishes (Cape galaxias Galaxias zebratus, n = 27; Cape kurper Sandelia capensis, n = 60; Breede River redfin Pseudobarbus burchelli, n = 77) were characterised and compared in three headwater streams in South Africa's Cape Fold Ecoregion using gut contents and stable isotope analyses. These data were analysed to ascertain whether the three species exploit distinct trophic niches. Both approaches provided evidence that these species occupy different trophic niches, though with some overlap. However, dietary differences among sites were not consistent and were probably influenced by site-specific factors like resource availability. Pseudobarbus burchelli had a broader niche breadth at Tierkloof Stream than the other two species, but not at Waaihoek or Tierstel Streams. Our results also suggest that P. burchelli consumed a more omnivorous diet than do the other two species, whereas S. capensis occupied a higher trophic position than the other two species and consumed vertebrates. Our findings suggest that these species occupy non-equivalent feeding niches in Cape Fold Ecoregion headwater streams, and that diet partitioning might facilitate their coexistence in these systems.     

SIMILARITY OF THE KINETICS OF INVERTASE ACTION IN VIVO AND IN VITRO

1. A method is given whereby the course of hydrolysis of sucrose by live yeast cells may be followed with precision equal to that found when invertase solutions prepared from autolyzed yeast are used to cause inversion. 2. The practical value of the equation of Nelson and Hitchcock as a means of following the course of enzymic hydrolysis of sucrose is hereby extended. 3. The inversion of sucrose by live yeast cells and by extracted invertase has been quantitatively compared. 4. The course of hydrolysis of sucrose by the invertase of Fleischmann''s yeast has been found to be identical in vivo and in vitro.     

Developing Porphyra/salmon integrated aquaculture for bioremediation and diversification of the aquaculture industry

For rapid growth and appropriate pigmentation,Porphyra requires the constant availability of nutrients, especially in summer when temperate waters are generally nutrient depleted. Cultivation near salmon cages allows the alleviation of this seasonal depletion by using the significant loading of fishf arms, which is then valued (wastes become fertilisers) and managed (competition for nutrients between desirable algal crops and problem species associated with severe disturbances). Porphyra,being an extremely efficient nutrient pump, is an excellent candidate for integrated aquaculture for bioremediation and economic diversification. Frequent harvesting provides for constant removal of significant quantities of nutrients from coastal waters, and for production of seaweeds of commercial value. The production of P. yezoensis being limited in the Gulf of Maine, an assessment of the potential of seven native north-west Atlantic Porphyra species is presently in progress. To enable the production of conchospores for net seeding, the phenology of these species and the conditions for their vegetative conchocelis exponential growth, conchosporangium induction, and conchospore maturation were determined. The development of integrated aquaculture systems is a positive initiative for optimising the efficiency of aquaculture operations, while maintaining the health of coastal waters. This revised version was published online in August 2006 with corrections to the Cover Date.     

Hydrophobic forces are responsible for the folding of a highly potent natriuretic peptide analogue at a membrane mimetic surface: An NMR study

A conformational study by nmr spectroscopy was performed with the highly active 28-residue hybrid natriuretic peptide analogue pBNP1 [M. Mimeault, A. De Léan, M. Lafleur, D. Bonenfant, and A. Fournier (1995) Biochemistry, Vol. 34, pp. 955–964], which consists of the cyclic peptide core of pBNP32 and the N- and C-terminal exocyclic segments of rANP(99–126). In purely aqueous solution pBNP1 exhibits random coil behavior as evidenced by the almost complete absence of structurally significant nmr observables. By contrast, elements of secondary structure emerged upon the addition of dodecylphosphocholine micelles to the aqueous sample. Nuclear Overhauser effect distance-restrained molecular dynamics simulations in conjunction with torsional angle determinations permitted the generation of a reasonable model of the lipid-bound conformation of pBNP1. According to this model, pBNP1 adopts turn-like features in the cyclic and C-terminal regions of the peptide, but remains quite flexible in the N-terminal segment. Two hydrophobic cores separated by a hydrophilic cleft were also evident in the generated structure. A mechanism is proposed whereby the hydrophobic interactions necessary to stabilize a folded structure of pBNP1 are facilitated by the presence of the membrane-like polar/apolar interface provided by the phospholipid micelles. © 1997 John Wiley & Sons, Biopoly 42: 37–48, 1997     

Impact of Extraction Methods on the Detectable Protein Complement of Metaproteomic Analyses of Marine Sediments

Metaproteomic analysis targets proteins, the catalytic entities in the habitat, thereby providing direct insights into the metabolic activity of the community studied. A major challenge still remaining for metaproteomics is the effective and comprehensive extraction of proteins from environmental samples, due to their high complexity with respect to organismic diversity and abundance range. Moreover, in certain habitats, the inherent matrix may interfere with protein extraction. In recent years, several studies reported different protein extraction methods for soils known for their complex geochemistry, but only three analyzed marine sediments that generally comprise different though similarly complex geochemistry. In this study, the impact of four different extraction methods was investigated for coastal North Sea and deep sea Pacific Ocean sediments. The extraction methods comprised (i) phenol, (ii) SDS, (iii) a mixture of SDS and phenol, and (iv) urea and thiourea. Prior to extraction, a cell and protein standard (CPS) was added to the sediment samples to trace recovery of proteins from different subcellular locations as well as dissolved BSA. While each extraction method detected distinct peptide complements, SDS‐phenol extraction generally achieved highest protein yield and most comprehensive CPS protein identification. Application of two different methods was shown to further improve proteome coverage.