Comparing the Ecological Impacts of Wind and Oil & Gas Development: A Landscape Scale Assessment

Energy production in the United States is in transition as the demand for clean and domestic power increases. Wind energy offers the benefit of reduced emissions, yet, like oil and natural gas, it also contributes to energy sprawl. We used a diverse set of indicators to quantify the ecological impacts of oil, natural gas, and wind energy development in Colorado and Wyoming. Aerial imagery was supplemented with empirical data to estimate habitat loss, fragmentation, potential for wildlife mortality, susceptibility to invasion, biomass carbon lost, and water resources. To quantify these impacts we digitized the land-use footprint within 375 plots, stratified by energy type. We quantified the change in impacts per unit area and per unit energy produced, compared wind energy to oil and gas, and compared landscapes with and without energy development. We found substantial differences in impacts between energy types for most indicators, although the magnitude and direction of the differences varied. Oil and gas generally resulted in greater impacts per unit area but fewer impacts per unit energy compared with wind. Biologically important and policy-relevant outcomes of this study include: 1) regardless of energy type, underlying land-use matters and development in already disturbed areas resulted in fewer total impacts; 2) the number and source of potential mortality varied between energy types, however, the lack of robust mortality data limits our ability to use this information to estimate and mitigate impacts; and 3) per unit energy produced, oil and gas extraction was less impactful on an annual basis but is likely to have a much larger cumulative footprint than wind energy over time. This rapid evaluation of landscape-scale energy development impacts could be replicated in other regions, and our specific findings can help meet the challenge of balancing land conservation with society’s demand for energy.     

In vitro anti-microbial activity of extracts from the callus cultures of some Nigella species

Crude methanol extracts from callus cultures of Nigella arvensis, N. damascena, N. hispanica, N. integrifolia, and N. sativa were investigated for their anti-microbial activity. Growth inhibition was determined in Gram-positive and Gram-negative bacterial strains as well as in yeast by using a broth-microdilution method. The results showed that the extracts of all calli tested exhibited significant anti-microbial activity, especially against Bacillus cereus, Staphylococcus aureus and Staphylococcus epidermidis. Compared with other Nigella species, a callus culture of N. hispanica was the most effective against the microorganisms used in this study.     

Population biology of two rare fern species: long life and long-lasting stability

? Premise of the study: This study describes the population dynamics of two rare fern species and evaluates the prospects of their survival. This is the first detailed demography study of ferns using transition matrix models. The study species, Asplenium adulterinum and A. cuneifolium, are restricted to serpentine rocks and differ in ploidy level and partly in habitat requirements. Both species are of interest in nature conservation. ? Methods: Single life-history traits were evaluated and transition matrix models were used to describe the dynamics of the populations. Population growth rates, elasticity values, and life-table response experiments were used to compare the dynamics between species, years, and different habitat types. Predicted population performance based on models was compared with real data on population growth. ? Key Results: All populations of both species are growing. Stable stage distribution based on stochastic simulation corresponds to current stage distribution. The most critical phase of the life cycle is stasis of large adult plants. Reproduction is of low importance. Extinction probability of small populations is low. Mean life span of individuals of both species is 30-50 yr. When compared with real data, the model successfully predicted population performance over 10 yr. ? Conclusion: Populations in the study region are not endangered, and current population dynamics are stable. Differences in life-history traits between species, probability of extinction between species and habitat, and different ploidy-and, thus, probably different dispersal ability-suggest the existence of metapopulation dynamics.     

Mutual regulation of plant phospholipase D and the actin cytoskeleton

Membrane lipids and cytoskeleton dynamics are intimately inter‐connected in the eukaryotic cell; however, only recently have the molecular mechanisms operating at this interface in plant cells been addressed experimentally. Phospholipase D (PLD) and its product phosphatidic acid (PA) were discovered to be important regulators in the membrane–cytoskeleton interface in eukaryotes. Here we report the mechanistic details of plant PLD–actin interactions. Inhibition of PLD by n‐butanol compromises pollen tube actin, and PA rescues the detrimental effect of n‐butanol on F‐actin, showing clearly the importance of the PLD–PA interaction for pollen tube F‐actin dynamics. From various candidate tobacco PLDs isoforms, we identified NtPLDβ1 as a regulatory partner of actin, by both activity and in vitro interaction assays. Similarly to published data, the activity of tobacco PIP₂‐dependent PLD (PLDβ) is specifically enhanced by F‐actin and inhibited by G‐actin. We then identified the NtPLDβ1 domain responsible for actin interactions. Using sequence‐ and structure‐based analysis, together with site‐directed mutagenesis, we identified Asn323 and Thr382 of NtPLDβ1 as the crucial amino acids in the actin‐interacting fold. The effect of antisense‐mediated suppression of NtPLDβ1 or NtPLDδ on pollen tube F‐actin dynamics shows that NtPLDβ1 is the active partner in PLD–actin interplay. The positive feedback loop created by activation of PLDβ by F‐actin and of F‐actin by PA provides an important mechanism to locally increase membrane–F‐actin dynamics in the cortex of plant cells.     

Differential Induction of Antimicrobial REGIII by the Intestinal Microbiota and Bifidobacterium breve NCC2950

The intestinal microbiota is a key determinant of gut homeostasis, which is achieved, in part, through regulation of antimicrobial peptide secretion. The aim of this study was to determine the efficiency by which members of the intestinal microbiota induce the antimicrobial peptide REGIII and to elucidate the underlying pathways. We showed that germfree mice have low levels of REGIII-γ in their ileum and colon compared to mice with different intestinal microbiota backgrounds. Colonization with a microbiota of low diversity (altered Schaedler flora) did not induce the expression of REGIII-γ as effectively as a complex community (specific pathogen free). Monocolonization with the probiotic Bifidobacterium breve, but not with the nonprobiotic commensal Escherichia coli JM83, upregulated REGIII-γ expression. Induction of REGIII-γ by B. breve was abrogated in mice lacking MyD88 and Ticam1 signaling. Both live and heat-inactivated B. breve but not spent culture medium from B. breve induced the expression of REGIII-α, the human ortholog and homolog of REGIII-γ, in human colonic epithelial cells (Caco-2). Taken together, the results suggest that REGIII-γ expression in the intestine correlates with the richness of microbiota composition. Also, specific bacteria such as Bifidobacterium breve NCC2950 effectively induce REGIII production in the intestine via the MyD88-Ticam1 pathway. Treatment with this probiotic may enhance the mucosal barrier and protect the host from infection and inflammation.