Isolation,Identification and Some Cultural Conditions of Streptomyces Species That Produce Water-insoluble Polyglucan Hydrolase

Cariogenic streptococci produce tenacious water-insoluble polysaccharides from sucrose and these form the structural intercellular matrix of dental plaque. Two Streptomyces species were isolated from soils on agar medium containing the water-insoluble polyglucan as a sole carbon source. They were identified as Streptomyces werraensis (strain F₁) and Streptomyces chartreusis (strain F₂). These strains produced extracellular enzymes which strongly solubilized the polyglucans from various strains of cariogenic streptococci. Strain F₂ produced polyglucanases under rather stationary cultural condition, while F₁ required vigorous aeration. The polyglucanases may provide a useful measure for the prevention and control of dental plaque formation,     

Use of a Gluconobacter frateurii Mutant to Prevent Dihydroxyacetone Accumulation during Glyceric Acid Production from Glycerol

To prevent dihydroxyacetone (DHA) by-production during glyceric acid (GA) production from glycerol using Gluconobacter frateurii, we used a G. frateurii THD32 mutant, ΔsldA, in which the glycerol dehydrogenase subunit-encoding gene (sldA) was disrupted, but ΔsldA grew much more slowly than the wild type, growth starting after a lag of 3 d under the same culture conditions. The addition of 1% w/v D-sorbitol to the medium improved both the growth and the GA productivity of the mutant, and ΔsldA produced 89.1 g/l GA during 4 d of incubation without DHA accumulation.     

Degradation of chemical alarm cues and assessment of risk throughout the day

The use of chemical information in assessment of predation risk is pervasive across animal taxa. However, by its very nature, chemical information can be temporally unreliable. Chemical cues persist for some period of time after they are released into the environment. Yet, we know surprisingly little about the rate of degradation of chemical cues under natural conditions and hence little about how they function in temporal risk assessment under natural conditions. Here, we conducted an experiment to identify a concentration of fresh alarm cues that evoke a strong antipredator response in coral reef damselfish, Pomacentrus ambonensis. We then tested the rate at which these alarm cues degraded under natural conditions in ocean water, paying attention to whether the rate of degradation varied throughout the day and whether the temporal pattern correlated with physicochemical factors that could influence the rate of degradation. Fresh alarm cues released into ocean water evoke strong avoidance responses in juvenile fish, while those aged for 30 min no longer evoke antipredator responses. Fish exposed to cues aged for 10 or 20 min show intermediate avoidance responses. We found a marked temporal pattern of response throughout the day, with much faster degradation in early to mid‐afternoon, the time of day when solar radiation, temperature, dissolved oxygen, and pH are nearing their peak. Ecologists have spent considerable effort elucidating the role of chemical information in mediating predator–prey interactions, yet we know almost nothing about the temporal dynamics of risk assessment using chemical information. We are in dire need of additional comparative field experiments on the rate of breakdown of chemical cues, particularly given that global change in UV radiation, temperature, and water chemistry could be altering the rates of degradation and the potential use of this information in risk assessment.     

A tool for protected area management: multivariate control charts ‘cope’ with rare variable communities

Performance assessment, impact detection, and the assessment of regulatory compliance are common scientific problems for the management of protected areas. Some habitats in protected areas, however, are rare and/or variable and are not often selected for study by ecologists because they preclude comparison with controls and high community variability makes meaningful change detection difficult. Shallow coastal saline lagoons are habitats that experience comparatively high levels of stress due to high physical variability. Lagoons are rare, declining habitats found in coastal regions throughout Europe (and elsewhere) where they are identified as one of the habitats most in need of protected area management. The infauna in the sediments of 25 lagoons were sampled. Temporal and spatial variation in three of these [protected] lagoons was investigated further over 5 years. In a multivariate analysis of community structure similarities were found between some lagoons, but in other cases communities were unique or specific to only two sites. The protected lagoons with these unique/specific communities showed significant temporal and spatial variation, yet none of the changes observed were attributed to human impacts and were interpreted as inherent variability. Multivariate control charts can operate without experimental controls and were used to assess community changes within the context of ‘normal’ lagoon variability. The aim of control chart analysis is to characterize background variability in a parameter and identify when a new observation deviates more than expected. In only 1 year was variability more than expected and corresponded with the coldest December in over 100 years. Multivariate control charts are likely to have wide application in the management of protected areas and other natural systems where variability and/or rarity preclude conventional analytical and experimental approaches but where assessments of condition, impact or regulatory compliance are nonetheless required.     

四种重楼属植物光合作用特征

Species of Paris (Trilliaceae) have often been used as medicinal plants. Because of excessive exploitation,in this regard the wild resource of Paris is almost exhausted. Some species of Paris were transplanted for use in photosynthesis research and for conservation purposes. In the present study, light and CO2 photosynthetic response curves were investigated in four Paris taxa: P.polyphylla var. yunnanensis and var. alba, P.mairei, and P.marmorata. Our results showed that P.marmorata had the highest maximum photosynthetic rate (Pmax; 8.6μmol·m-2·s-1), light saturation point (LSP; 827μmol·m-2·s-1), maximum electron transport rate (Jmax; 39.9mol·m-2·s-1), a relatively high maximum carboxylation rate (Vcmax; 28.9μmol·m-2·s-1) and carbon dioxide saturation point (Cisat; 726μmol·mol-1), but a lower light compensation point (LCP; 6.23μmol·m-2·s-1) and the lowest carbon dioxide compensation point (Г*; 20.7μmol·mol-1). This suggests that P.marmorata is well adapted to light and CO2; however it has a low ability to acclimate to environmental stress as indicated by low water use efficiency (WUE) in high light conditions. P.polyphylla var. yunnanensis had the highest light compensation point (LCP; 10.1μmol·m-2·s-1), carbon dioxide compensation point (Г*; 35.3μmol·mol-1), carbon dioxide saturation point (Cisat; 727μmol·mol-1), relatively high maximum photosynthetic rate (Pmax; 7.5μmol·m-2·s-1) and light saturation point (LSP; 728μmol·m-2·s-1), maximum light saturated electron transfer rate (Jmax; 37.7μmol·m-2·s-1), suggesting that it is suitable for conditions of higher light and CO2 concentration. This taxon can adapt to adverse conditions, as suggested by high WUE under increased CO2 concentration. In contrast, P.polyphylla var. alba exhibited a relatively lower apparent quantum yield (AQY; 0.037μmol·mol-1) and poorer growth performance than the other taxa. We suggest from our results that different light and water conditions are suitable for the growth of the different taxa. Photosynthesis assimilation efficiency and production can be increased by raising humidity for P.polyphylla var. yunnanensis and P.marmorata. To protect plants of P.polyphylla var. alba from strong sunshine, they should be shaded from March to mid June.     

Ecology and Behaviour of Burton's Legless Lizard(Lialis burtonis,Pygopodidae) in Tropical Australia

The elongate, functionally limbless flap-footed lizards(family Pygopodidae) are found throughout Australia, ranging into southern New Guinea. Despite their diversity and abundance in most Australian ecosystems, pygopodids have attracted little scientific study. An intensive ecological study of one pygopodid, Burton's legless lizard(Lialis burtonis Gray 1835), was conducted in Australia's tropical Northern Territory. L. burtonis eats nothing but other lizards, primarily skinks, and appears to feed relatively infrequently(only 20.8% of stomachs contained prey). Ovulation and mating occur chiefly in the late dry-season(beginning around September), and most egg-laying takes place in the early to middle wet-season(November–January). Females can lay multiple clutches per year, some of which may be fertilised with stored sperm. Free-ranging L. burtonis are sedentary ambush foragers, with radio-tracked lizards moving on average 5 m/day. Most foraging is done diurnally, but lizards may be active at any time of day or night. Radiotracked lizards were usually found in leaf-litter microhabitats, a preference that was also evident in habitat-choice experiments using field enclosures. Lizards typically buried themselves in 6–8 cm of litter; at this depth, they detect potential prey items while staying hidden from predators and prey and avoiding lethally high temperatures.     

Environmental implications of the use of agro‐industrial residues for biorefineries: application of a deterministic model for indirect land‐use changes

Biorefining agro‐industrial biomass residues for bioenergy production represents an opportunity for both sustainable energy supply and greenhouse gas (GHG) emissions mitigation. Yet, is bioenergy the most sustainable use for these residues? To assess the importance of the alternative use of these residues, a consequential life cycle assessment (LCA) of 32 energy‐focused biorefinery scenarios was performed based on eight selected agro‐industrial residues and four conversion pathways (two involving bioethanol and two biogas). To specifically address indirect land‐use changes (iLUC) induced by the competing feed/food sector, a deterministic iLUC model, addressing global impacts, was developed. A dedicated biochemical model was developed to establish detailed mass, energy, and substance balances for each biomass conversion pathway, as input to the LCA. The results demonstrated that, even for residual biomass, environmental savings from fossil fuel displacement can be completely outbalanced by iLUC, depending on the feed value of the biomass residue. This was the case of industrial residues (e.g. whey and beet molasses) in most of the scenarios assessed. Overall, the GHGs from iLUC impacts were quantified to 4.1 t CO₂‐eq.ha^?1_demanded yr^?1 corresponding to 1.2–1.4 t CO₂‐eq. t^?1 dry biomass diverted from feed to energy market. Only, bioenergy from straw and wild grass was shown to perform better than the alternative use, as no competition with the feed sector was involved. Biogas for heat and power production was the best performing pathway, in a short‐term context. Focusing on transport fuels, bioethanol was generally preferable to biomethane considering conventional biogas upgrading technologies. Based on the results, agro‐industrial residues cannot be considered burden‐free simply because they are a residual biomass and careful accounting of alternative utilization is a prerequisite to assess the sustainability of a given use. In this endeavor, the iLUC factors and biochemical model proposed herein can be used as templates and directly applied to any bioenergy consequential study involving demand for arable land.     

Potential impacts on ecosystem services of land use transitions to second‐generation bioenergy crops in GB

We present the first assessment of the impact of land use change (LUC) to second‐generation (2G) bioenergy crops on ecosystem services (ES) resolved spatially for Great Britain (GB). A systematic approach was used to assess available evidence on the impacts of LUC from arable, semi‐improved grassland or woodland/forest, to 2G bioenergy crops, for which a quantitative ‘threat matrix’ was developed. The threat matrix was used to estimate potential impacts of transitions to either Miscanthus, short‐rotation coppice (SRC, willow and poplar) or short‐rotation forestry (SRF). The ES effects were found to be largely dependent on previous land uses rather than the choice of 2G crop when assessing the technical potential of available biomass with a transition from arable crops resulting in the most positive effect on ES. Combining these data with constraint masks and available land for SRC and Miscanthus (SRF omitted from this stage due to lack of data), south‐west and north‐west England were identified as areas where Miscanthus and SRC could be grown, respectively, with favourable combinations of economic viability, carbon sequestration, high yield and positive ES benefits. This study also suggests that not all prospective planting of Miscanthus and SRC can be allocated to agricultural land class (ALC) ALC 3 and ALC 4 and suitable areas of ALC 5 are only minimally available. Beneficial impacts were found on 146 583 and 71 890 ha when planting Miscanthus or SRC, respectively, under baseline planting conditions rising to 293 247 and 91 318 ha, respectively, under 2020 planting scenarios. The results provide an insight into the interplay between land availability, original land uses, bioenergy crop type and yield in determining overall positive or negative impacts of bioenergy cropping on ecosystems services and go some way towards developing a framework for quantifying wider ES impacts of this important LUC.     

On mitigating emissions leakage under biofuel policies

A reason for much pessimism about the environmental benefits of today's biofuels, essentially corn and sugarcane ethanol, is the so‐called indirect land‐use change (ILUC) emissions associated with expanding biofuel production. While there exist several simulation‐based estimates of indirect emissions, the empirical basis underlying key input parameters to such simulations is not beyond doubt, while empirical verification of indirect emissions is hard. Regardless, regulators have adopted global warming intensity ratings for biofuels based on those simulations and in some case are holding regulated firms accountable for (some forms of) leakage. Suffice to say that both the estimates of and the approach to regulating leakage are controversial. The objective of this study is therefore to review a wider economic in order to identify a broader set of policy options for mitigating emissions leakage. We find that controlling leakage by affixing responsibility to regulated firms lacks support in the broader literature, which emphasizes alternative approaches.     

Simulated impact of the renewable fuels standard on US Conservation Reserve Program enrollment and conversion

A socioeconomic model is used to estimate the land‐use implications on the U.S. Conservation Reserve Program from potential increases in second‐generation biofuel production. A baseline scenario with no second‐generation biofuel production is compared to a scenario where the Renewable Fuels Standard (RFS2) volumes are met by 2022. We allow for the possibility of converting expiring CRP lands to alternative uses such as conventional crops, dedicated second‐generation biofuel crops, or harvesting existing CRP grasses for biomass. Results indicate that RFS2 volumes (RFS2‐v) can be met primarily with crop residues (78% of feedstock demand) and woody residues (19% of feedstock demand) compared with dedicated biomass (3% of feedstock demand), with only minimal conversion of cropland (0.27 million hectares, <1% of total cropland), pastureland (0.28 million hectares of pastureland, <1% of total pastureland), and CRP lands (0.29 million hectares of CRP lands, 3% of existing CRP lands) to biomass production. Meeting RFS2 volumes would reduce CRP re‐enrollment by 0.19 million hectares, or 4%, below the baseline scenario where RFS2 is not met. Yet under RFS2‐v scenario, expiring CRP lands are more likely to be converted to or maintain perennial cover, with 1.78 million hectares of CRP lands converting to hay production, and 0.29 million hectares being harvested for existing grasses. A small amount of CRP is harvested for existing biomass, but no conversion of CRP to dedicated biomass crops, such as switchgrass, are projected to occur. Although less land is enrolled in CRP under RFS2‐v scenario, total land in perennial cover increases by 0.15 million hectares, or 2%, under RFS2‐v. Sensitivity to yield, payment and residue retention assumptions are evaluated.