Comparison of fatty acids and elemental nutrients in periphyton, invertebrates, and cutthroat trout (Oncorhynchus clarki) in conifer and alder streams of western Washington state

Organism growth and reproduction are often limited by nutrient availability in freshwater ecosystems where, in some cases, food webs are primarily supported by allochthonous organic matter. Therefore, we hypothesized that the composition of riparian vegetation would influence the variability of N, P, and fatty acid content of in-stream consumers. Specifically, we predicted that organisms living in alder streams would have higher levels of N, P, and polyunsaturated fatty acids than organisms in coniferous streams. To determine this, we sampled fresh and aged leaf litter, periphyton, invertebrates, and cutthroat trout (Oncorhynchus clarki) from 6 streams in western Washington state: 3 streams had high densities of nitrogen-fixing red alder (Alnus rubra) in the riparian zone, whereas 3 had high densities of conifers. We found fresh alder litter had twice the total polyunsaturated fatty acid concentrations of hemlock vegetation while there were few statistical differences among aged alder and aged hemlock vegetation. Multidimensional plots showed fatty acid profiles were unique to vegetation and fish while periphyton and invertebrates shared the same multidimensional space. We used a mixed model to determine the relative importance of vegetation type (fixed factor: conifer or alder), trophic levels (fixed factor: periphyton, primary consumer, or fish), and streams (random factor) on individual fatty acid concentrations. Total polyunsaturated fatty acids, 16:0, 20:1, 20:3n6 and total n3 were the only fatty acids influenced by stream vegetation (vegetation + stream model or full model). 67% of the fatty acids were best supported by the trophic + stream model. Nitrogen, P, Ca, Fe, C:N, N:P, and C:N:P were all best supported by the trophic level + stream model, and Zn was the only nutrient supported best by the full model. Correlations of n3 and n6 fatty acid concentrations between periphyton and primary consumers, and primary consumers with trout indicated several fatty acid metrics, such as n3:n6, showed food resources may affect relative fatty acid abundances of consumers. Although vegetation type did not influence relative fatty acids of stream organisms, the importance of trophic level likely indicates organisms have different physical requirements for fatty acids. The significance of a random factor, ‘stream,’ suggests that the relative abundances of fatty acids in periphyton, invertebrates, and trout are stream-specific and are responding to local environmental or communal variables.     

Nisin inducible production of listeriolysin O in <Emphasis Type="Italic">Lactococcus lactis</Emphasis> NZ9000

Background  

Listeria monocytogenesis a well-characterized food-borne pathogen that infects pregnant women and immunocompromised individuals. Listeriolysin O (LLO) is the major virulence factor of the pathogen and is often used as a diagnostic marker for detection of L. monocytogenes. In addition, LLO represents a potent antigen driving T cell-mediated immunity during infection. In the present work, Lactococcus lactisNZ9000 was used as an expression host to hyper-produce LLO under inducible conditions using the NICE (NIsin Controlled Expression) system. We created a modified pNZ8048 vector encoding a six-His-tagged LLO downstream of the strong inducible PnisA promoter.     

Oral high-dose atorvastatin treatment in relapsing-remitting multiple sclerosis

Background

Recent data from animal models of multiple sclerosis (MS) and from a pilot study indicated a possible beneficial impact of statins on MS.

Methodology/Principal Findings

Safety, tolerability and effects on disease activity of atorvastatin given alone or in combination with interferon-beta (IFN-β) were assessed in a phase II open-label baseline-to-treatment trial in relapsing-remitting MS (RRMS). Patients with at least one gadolinium-enhancing lesion (CEL) at screening by magnetic resonance imaging (MRI) were eligible for the study. After a baseline period of 3 monthly MRI scans (months −2 to 0), patients followed a 9-month treatment period on 80 mg atorvastatin daily. The number of CEL in treatment months 6 to 9 compared to baseline served as the primary endpoint. Other MRI-based parameters as well as changes in clinical scores and immune responses served as secondary endpoints. Of 80 RRMS patients screened, 41 were included, among them 16 with IFN-β comedication. The high dose of 80 mg atorvastatin was well tolerated in the majority of patients, regardless of IFN-β comedication. Atorvastatin treatment led to a substantial reduction in the number and volume of CEL in two-sided multivariate analysis (p = 0.003 and p = 0.008). A trend towards a significant decrease in number and volume of CEL was also detected in patients with IFN-β comedication (p = 0.060 and p = 0.062), in contrast to patients without IFN-β comedication (p = 0.170 and p = 0.140). Immunological investigations showed no suppression in T cell response but a significant increase in IL-10 production.

Conclusions/Significance

Our data suggest that high-dose atorvastatin treatment in RRMS is safe and well tolerated. Moreover, MRI analysis indicates a possible beneficial effect of atorvastatin, alone or in combination with IFN-β, on the development of new CEL. Thus, our findings provide a rationale for phase II/III trials, including combination of atorvastatin with already approved immunomodulatory therapy regimens.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00616187","term_id":"NCT00616187"}}NCT00616187     

Assessment of Canopy Structure, Light Interception, and Light-use Efficiency of First Year Regrowth of Shrub Willow (Salix sp.)

According to the light-use efficiency model, differential biomass production among willow varieties may be attributed either to differences in the amount of light intercepted, the efficiency with which the intercepted light is converted to aboveground biomass, or both. In this study, variation in aboveground biomass production (AGBP) was analyzed in relation to fraction of incoming radiation intercepted (IPAR_F) and light-use efficiency (LUE) for five willow varieties. The plants were grown in a short-rotation woody crop (SRWC) system and were in their first year of regrowth on a 5 year old root system. The study was conducted during a two-month period (June 15th–August 15th, 2001) when growing conditions were deemed most favorable. The objectives were: (1) to assess the relative importance of IPAR_F in explaining variation in AGBP, and (2) to identify the key drivers of variation in LUE from a suite of measured leaf and canopy-level traits. Aboveground biomass production varied nearly three-fold among genotypes (3.55–10.02 Mg ha^?1), while LUE spanned a two-fold range (1.21–2.52 g MJ^?1). At peak leaf area index (LAI), IPAR_F ranged from 66%–92%. Nonetheless, both IPAR_F and LUE contributed to AGBP. An additive model combining photosynthesis on leaf area basis (A_area), leaf mass per unit area (LMA), and light extinction coefficient (k) produced the most compelling predictors of LUE. In a post-coppice willow crop, the ability to maximize IPAR_F and LUE early in the growing season is advantageous for maximizing biomass production.     

Spiking behavior and epileptiform oscillations in a discrete model of cortical neural networks

Summary We investigate the phenomenon of epileptiform activity using a discrete model of cortical neural networks. Our model is reduced to the elementary features of neurons and assumes simplified dynamics of action potentials and postsynaptic potentials. The discrete model provides a comparably high simulation speed which allows the rendering of phase diagrams and simulations of large neural networks in reasonable time. Further the reduction to the basic features of neurons provides insight into the essentials of a possible mechanism of epilepsy. Our computer simulations suggest that the detailed dynamics of postsynaptic and action potentials are not indispensable for obtaining epileptiform behavior on the system level. The simulation results of autonomously evolving networks exhibit a regime in which the network dynamics spontaneously switch between fluctuating and oscillating behavior and produce isolated network spikes without external stimulation. Inhibitory neurons have been found to play an important part in the synchronization of neural firing: an increased number of synapses established by inhibitory neurons onto other neurons induces a transition to the spiking regime. A decreased frequency accompanying the hypersynchronous population activity has only occurred with slow inhibitory postsynaptic potentials.     

The influence of infant facial cues on adoption preferences

Trivers’s theory of parental investment suggests that adults should decide whether or not to invest in a given infant using a cost-benefit analysis. To make the best investment decision, adults should seek as much relevant information as possible. Infant facial cues may serve to provide information and evoke feelings of parental care in adults. Four specific infant facial cues were investigated: resemblance (as a proxy for kinship), health, happiness, and cuteness. It was predicted that these cues would influence feelings of parental care for both sexes, but that resemblance would be more important for men than women because of the importance of paternity uncertainty in the ancestral environment. Seventy-six men and 76 women participated in a hypothetical adoption task in which they made judgments of infant faces. Average zero-order, partial, and component score correlations all revealed that men placed primary emphasis on cues of resemblance, while women placed primary emphasis on cues of health and cuteness (cues of infant quality). The correlations also showed that men placed a significantly greater emphasis on cues of resemblance than did women. This research was supported by a Queen’s University Graduate Award (first author) and a Senior Research Fellowship from the Ontario Mental Health Foundation (second author). Anthony Volk is a Ph.D. candidate at Queen’s University, studying parental investment. Vernon L. Quinsey is a professor of psychology and psychiatry at Queen’s University. His research focuses on forensic and evolutionary psychology. An erratum to this article is available at .     

A novel use of the hyperinsulinemic-euglycemic clamp technique to estimate insulin sensitivity of systemic lipolysis.

The aim of the present study was to assess whether a standard hyperinsulinemic-euglycemic clamp can provide an estimate for the antilipolytic insulin sensitivity. For this purpose, we infused 9 non-obese, healthy volunteers with [2H5]glycerol and used the glycerol rate of appearance (Ra) in plasma as an index for systemic lipolysis during a standard (1 mU/kg x min, 120 min) and a 3-step (0.1, 0.25, 1.0 mU/kg x min) hyperinsulinemic-euglycemic clamp. The insulin concentration, which half-maximally suppressed lipolysis (EC50) in the three-step clamp, was considered to be the gold standard for the antilipolytic insulin sensitivity. Glycerol Ra decreased from 1.53+/-0.11 micromol/kg x min to 0.60+/-0.09 micromol/kg x min (p <0.001) during the standard clamp. The decrease in Ra at most time points during the standard clamp significantly correlated with the EC50. The highest correlation for the % decrease of glycerol Ra from baseline was found at 60 min (r = 0.96, p < 0.001) making this parameter a useful index for the antilipoytic insulin sensitivity. Neither plasma glycerol nor plasma free fatty acid (FFA) concentrations were significantly correlated with the EC50. In conclusion, the standard hyperinsulinemic-euglycemic clamp in combination with isotopic determination of glycerol Ra provides a reasonable estimate for the antilipolytic insulin sensitivity. In healthy subjects, the parameter best suited to estimate the insulin EC50 (by linear correlation) was the percentage decrease of glycerol Ra at 60 min.     

Effects of Resident Soil Fungi and Land Use History Outweigh Those of Commercial Mycorrhizal Inocula: Testing a Restoration Strategy in Unsterilized Soil

Arbuscular mycorrhizal fungi (AMF) have numerous effects on temperate grassland ecosystems, but prairie restorations are frequently located in sites with depauperate AMF communities. In this greenhouse study, four native species (Schizachyrium scoparium, Elymus canadensis, Monarda punctata, and Aster ericoides) and an invasive grass (Bromus inermis) were grown in unsterilized field soils and treated with two types of commercial AMF inoculum. Inocula were applied at one and two times the manufacturers' suggested rate. Soil was collected from a meadow enrolled in the Conservation Reserve Program (CRP), and from an active agricultural field. Inoculum addition had no effect on biomass or percent colonization by AMF for any grass species, regardless of soil type. Inoculum type significantly affected Aster biomass and percent colonization, although pairwise comparisons of treated individuals and controls were not significant. The overall lack of effectiveness of the commercial inocula may reflect the small number of propagules added, even when used at twice the recommended rate. Higher rates of fungal colonization in all three grasses and increased biomass in the native grasses were observed in individuals grown in the CRP soil. Plants were also colonized by dark septate endophytic fungi; for Schizachyrium, endophyte colonization was significantly greater in tilled than CRP soil. Our results indicate that an existing soil fungal community promotes colonization by AMF more than the addition of commercial inocula, and that soil characteristics associated with land use history significantly affect the growth of native species in a restoration setting.     

Evaluation of APOE polymorphisms and the risk for age-related macular degeneration in a Southeastern Brazilian population

This study aimed to evaluate the role of APOE polymorphisms (rs429358 and rs7412) in the risk of age-related macular degeneration in a sample of the Southeastern Brazilian population. Seven hundred and five unrelated individuals were analyzed, 334 with age-related macular degeneration (case group), and 371 without the disease (control group). In the case group, patients were further stratified according to disease phenotypes, divided into dry and wet age-related macular degeneration, and non-advanced and advanced age-related macular degeneration. APOE polymorphisms (rs429358 and rs7412) were evaluated through polymerase chain reaction and direct sequencing. In the comparison of cases vs. controls, none of the associations reached statistical significance, considering the Bonferroni-adjusted P-value, although there was a suggestive protection for the E3/E4 genotype (OR = 0.626; P-value = 0.037) and E4 carriers (OR = 0.6515; P-value = 0.047). Statistically significant protection for both the E3/E4 genotype and E4 carriers was observed in the comparisons: advanced age-related macular degeneration vs. controls (OR = 0.3665, P-value = 0.491 × 10⁻³ and OR = 0.4031, P-value = 0.814 × 10⁻³, respectively), advanced age-related macular degeneration vs. non-advanced age-related macular degeneration (OR = 0.2529, P-value = 0.659 × 10⁻⁴ and OR = 0.2692, P-value = 0.631 × 10⁻⁴, respectively). In the comparison of wet age-related macular degeneration vs. control, protection was statistically significant only for E3/E4 (OR = 0.4052, P-value = 0.001). None of the comparisons demonstrated any significant association for E2 genotypes or E2 carriers in age-related macular degeneration risk in this study. Findings suggest a protective role of the E4 haplotype in the APOE gene in the risk for advanced and wet forms of age-related macular degeneration, in a sample of the Brazilian population. To our knowledge, this is the first Brazilian study to show the association between APOE polymorphisms and age-related macular degeneration.