Combining energetic profitability and cover effects to evaluate salmonid habitat quality

Recent studies have demonstrated that the energetic profitability (net energy intake potential; NEI potential) of a habitat, which is calculated as the gross energy gain from foraging minus the energy expenditure from swimming at a focal point, may be a useful tool for predicting the salmonid biomass. The effectiveness of the NEI potential should be tested in various systems. Even if the NEI potential is validated, its predictive accuracy and transferability could be limited if the cover habitat, which is known to be an important factor for determining salmonid abundance, is not considered. We tested whether the NEI potential is effective for predicting the salmonid biomass even in a stream with abundant cover and whether combining the NEI potential and cover effects can improve the predictability of fish biomass using a generalized linear model. Our results demonstrated that the NEI potential could generally predict the fish biomass (percent deviance explained?=?79.9 %), and the model that incorporated both the NEI potential and the cover ratio improved the predictive accuracy (percent deviance explained?=?88.5 %). These results suggest that energetic profitability can be an effective indicator for assessing habitat quality and is relatively transferable to other systems. Furthermore, when cover effects are considered, the habitat quality is more accurately represented; thus, combining the energetic profitability and the cover effects might improve the transferability of the assessment across habitats.     

Spatial Prioritization for Biodiversity Restoration: A Simple Framework Referencing Past Species Distributions

The spatial prioritization of biodiversity restoration sites on a national scale lags behind that of protected areas. We present a simple framework for spatial restoration prioritization using complementarity analysis based on the differences between past and present species distributions and restoration feasibility. In the framework, sites that were not only diverse or unique in the past (high restoration potential), but also have high restoration feasibility (e.g. low anthropogenic pressures) are ranked higher. We applied the framework to endangered bird species that breed in Japan for which distribution data were available from nationwide distribution censuses conducted in 1978 and 1998. The data were compiled in a 20‐km grid resolution across Japan. We incorporated the degree of urbanization and number of farmers as a cost to optimize the sets of cells with regard to restoration feasibility. We successfully identified candidate sets of restoration cells, in which at most six can be allocated for each species under the constraint that the total area selected does not exceed 15% of the degraded cells. At most, 11 cells were allocated for each species under the constraint that restoration cells were within 15% of all ecosystem types. Comparison with the distribution of existing nature restoration sites revealed that only 9.3 or 9.7% (depended on the constraint) of high‐priority cells overlapped cells including existing restoration sites. Our framework provides an objective, efficient method to obtain a testable plan for biodiversity restoration, which might contribute to the attainment of the 2020 target set by the Convention on Biological Diversity .     

A proposal of framework to obtain an integrated biodiversity indicator for agricultural ponds incorporating the simultaneous effects of multiple pressures

One of the promising approaches to monitoring biodiversity is assessing the status of pressures driving the biodiversity state. To achieve this, we need to identify the principal pressures that cause simultaneous biodiversity loss across taxonomic groups and clarify how multiple pressures act synergistically or at least simultaneously to decrease biodiversity in the focal ecosystem. Here, we used a series of 64 ponds as a case study and we developed a framework for an integrated biodiversity indicator that took into consideration the estimated relative importance of multiple pressures. The indicator is defined as a function of the pressure(s) and is parameterized to explain a number of individual indicators of biodiversity, such as richness, abundance, and functional diversity of focal taxa. We selected aquatic macrophytes, Odonata, and benthic macroinvertebrates as the focal taxa. In addition, we focused on three types of pressure: eutrophication (represented by total phosphorus, total nitrogen, suspended solids, chlorophyll a, and density of cyanobacteria of pond water), habitat destruction (land-use type around the pond and pond bank protection), and invasive alien species (abundance of bluegill, largemouth bass, red swamp crayfish, and American bullfrog). We then evaluated the relationships among direct pressures and the individual biodiversity indicators and used a hierarchical Bayesian approach to calculate the integrated biodiversity indicator. Using this framework, we demonstrated that eutrophication had greater effects on the state of biodiversity of the agricultural ponds than did habitat destruction or the presence of invasive alien species. We also showed that the integrated indicator could well explain the behaviors of several individual biodiversity indicators, including total richness, endangered species richness, and functional diversity of focal taxa. These results demonstrate the advantages of the framework in providing a more practical method for assessing biodiversity, and quantifying the relative importance of the major threats to biodiversity to prioritize strategies in conservation planning and policy making.     

Mucosal Immunogenicity of Genetically Modified Lactobacillus acidophilus Expressing an HIV-1 Epitope within the Surface Layer Protein

Surface layer proteins of probiotic lactobacilli are theoretically efficient epitope-displaying scaffolds for oral vaccine delivery due to their high expression levels and surface localization. In this study, we constructed genetically modified Lactobacillus acidophilus strains expressing the membrane proximal external region (MPER) from human immunodeficiency virus type 1 (HIV-1) within the context of the major S-layer protein, SlpA. Intragastric immunization of mice with the recombinants induced MPER-specific and S-layer protein-specific antibodies in serum and mucosal secretions. Moreover, analysis of systemic SlpA-specific cytokines revealed that the responses appeared to be Th1 and Th17 dominant. These findings demonstrated the potential use of the Lactobacillus S-layer protein for development of oral vaccines targeting specific peptides.     

Serine residues responsible for tetracycline transport are on a vertical stripe including Asp-84 on one side of transmembrane helix 3 in transposon Tn10-encoded tetracycline/H+ antiporter of Escherichia coli.

Putative transmembrane helix 3 of the tetracycline/H+ antiporter encoded by a transposon, Tn10, contains four serine residues, Ser-77, Ser-82, Ser-91 and Ser-92. Each of these serine residues was replaced by site-directed mutagenesis. Of these four serine residues, Ser-77 was important for the transport function, and a bulky side chain at position 91 hindered substrate translocation, whereas Ser-82 and Ser-92 did not play any role. Ser-77 and Ser-91 are on the same vertical stripe, that includes the essential Asp-84, on the hydrophilic side of putative helix 3. These observations suggest that helix 3 is part of the tetracycline translocation channel across the membrane.     

Involvement of Cyanogens in the Promotion of Germination of Cocklebur Seeds in Response to Various Nitrogenous Compounds, Inhibitors of Respiratory and Ethylene

Nitrogenous inhibitors of respiration, namely, KCN, NaN₃ andNH₂OH, which promote the germination of cocklebur (Xanthiumpennsylvanücum Wallr.) seeds, enhanced the accumulationof cyanogenic compounds. Urea and cyanamide, which were ineffective,did not. Part of the exogenously applied KCN was converted tocyanogenic glycosides and lipids, but these compounds were onlyproduced at low levels in NaN₃-treated seeds. Exposure to NH₂OHcaused a slight accumulation of both types of cyanogenic compounds.Thiourea, effective in stimulating germination, did not increasethe cyanogenic compounds, which suggests that the mechanismof its effect on germination is different from that of othernitrogenous compounds. Thiocyanate had a slightly promotiveeffect and caused minor increases in the levels of cyanogeniccompounds. Ethylene increased the metabolic utilization of the accumulatedcyanogens in response to KCN or NaN₃. The response to ethyleneof seeds in secondary dormancy was restored only after pre-treatmentwith KCN or NaN₃. The response occurred once the level of cyanogenshad increased. By contrast, enhancement of the effects of KCNand NaN₃ on germination by propyl gallate or benzohydroxamate,inhibitors of CN-resistant respiration, was accompanied by theincreased accumulation of cyanogens within the seeds that hadbeen exposed to KCN or NaN₃ in combination with the other typesof respiratory inhibitors. Thus, it is suggested that endogenouscyanogens might be involved in the germination of cockleburseeds. (Received December 20, 1995; Accepted April 9, 1996)     

Three-dimensional structure of gurmarin,a sweet taste-suppressing polypeptide

Summary The solution structure of gurmarin was studied by two-dimensional proton NMR spectroscopy at 600 MHz. Gurmarin, a 35-amino acid residue polypeptide recently discovered in an Indian-originated tree Gymnema sylvestre, selectively suppresses the neural responses of rat to sweet taste stimuli. Sequence-specific protons. The three-dimensional solution structure was determined by simulated-annealing calculations on the basis of 135 interproton distance constraints derived from NOEs, six distance constraints for three hydrogen bonds and 16 dihedral angle constraints derived from coupling constants. A total of 10 structures folded into a well-defined structure with a triple-stranded antiparallel -sheet. The average rmsd values between any two structures were 1.65±0.39 Å for the backbone atoms (N, C, C) and 2.95±0.27 Å for all heavy atoms. The positions of the three disulfide bridges, which could not be deterermined chemically, were estimated to be Cys³–Cys¹⁸, Cys¹⁰–Cys²³ and Cys¹⁷–Cys³³ on the basis of the NMR distance constraints. This disulfide bridge pattern in gurmarin turned out to be analogous to that in -conotoxin and Momordica charantia trypsin inhibitor-II, and the topology of folding was the same as that in -conotoxin.Abbreviations DQF-COSY double-quantum-filtered correlated spectroscopy - HOHAHA homonuclear Hartmann-Hahn spectroscopy - NOESY nuclear Overhauser enhancement spectroscopy - ppm parts per million; rmsd, root-mean-square deviation - TSP 3-(trimethylsilyl)-2,2,3,3-tetradeutero-propionate