The importance of scale and spatial variables for the fungivorous beetle Bolitophagus reticulatus (Coleoptera, Tenebrionidae) in a fragmented forest landscape

Effects of isolation, habitat size and several microhabitat variables on presence/absence of the monophagous Bolitophagus reticulatus (L.) (Coleoptera. Tenebrionidae) were investigated in 58 forest fragments in an agricultural landscape (15 km²) in south-eastern Norway, All potential habitats of the beetle, dead Fomes fomentarius (L,) Kiekx basidiocarps (n = 587), were collected from trees (n = l85) within the study area. The basidiocarps were dissected and the number of B, reticulatus specimens (larvae, pupae and adults) counted. The material was analysed at four distinguishable spatial scales; basidiocarp-. tree-, tree-group- and forest island level. Different patterns of beetle presence emerged at the different scales, increasing habitat size and decreasing degree of isolation increased the probability of B, reticulatus presence at three (basidiocarp-, tree- and forest island level) and one (tree level) scales, respectively, whilst no such trends were found at the fourth level (tree-group level). Increasing insolation and thereby higher ambient temperatures, indicated by several microhabitat variables, improved the probability of beetle presence amongst the trees. The number of beetle specimens correlated positively with an increase in the habitat size at the tree level.     

Extracellular identification of a processed type II ComR/ComS pheromone of Streptococcus mutans

The competence-stimulating peptide (CSP) and the sigX-inducing peptide (XIP) are known to induce Streptococcus mutans competence for genetic transformation. For both pheromones, direct identification of the native peptides has not been accomplished. The fact that extracellular XIP activity was recently observed in a chemically defined medium devoid of peptides, as mentioned in an accompanying paper (K. Desai, L. Mashburn-Warren, M. J. Federle, and D. A. Morrison, J. Bacteriol. 194:3774-3780, 2012), provided ideal conditions for native XIP identification. To search for the XIP identity, culture supernatants were filtered to select for peptides of less than 3 kDa, followed by C(18) extraction. One peptide, not detected in the supernatant of a comS deletion mutant, was identified by tandem mass spectrometry (MS/MS) fragmentation as identical to the ComS C-terminal sequence GLDWWSL. ComS processing did not require Eep, a peptidase involved in processing or import of bacterial small hydrophobic peptides, since eep deletion had no inhibitory effect on XIP production or on synthetic XIP response. We investigated whether extracellular CSP was also produced. A reporter assay for CSP activity detection, as well as MS analysis of supernatants, revealed that CSP was not present at detectable levels. In addition, a mutant with deletion of the CSP-encoding gene comC produced endogenous XIP levels similar to those of a nondeletion mutant. The results indicate that XIP pheromone production is a natural phenomenon that may occur in the absence of natural CSP pheromone activity and that the heptapeptide GLDWWSL is an extracellular processed form of ComS, possibly the active XIP pheromone. This is the first report of direct identification of a ComR/ComS pheromone.     

Appearance frequency modulated gene set enrichment testing

Background  

Gene set enrichment testing has helped bridge the gap from an individual gene to a systems biology interpretation of microarray data. Although gene sets are defined a priori based on biological knowledge, current methods for gene set enrichment testing treat all genes equal. It is well-known that some genes, such as those responsible for housekeeping functions, appear in many pathways, whereas other genes are more specialized and play a unique role in a single pathway. Drawing inspiration from the field of information retrieval, we have developed and present here an approach to incorporate gene appearance frequency (in KEGG pathways) into two current methods, Gene Set Enrichment Analysis (GSEA) and logistic regression-based LRpath framework, to generate more reproducible and biologically meaningful results.     

Influence of microRNA deregulation on chaperone-mediated autophagy and α-synuclein pathology in Parkinson's disease

The presence of α-synuclein aggregates in the characteristic Lewy body pathology seen in idiopathic Parkinson''s disease (PD), together with α-synuclein gene mutations in familial PD, places α-synuclein at the center of PD pathogenesis. Decreased levels of the chaperone-mediated autophagy (CMA) proteins LAMP-2A and hsc70 in PD brain samples suggests compromised α-synuclein degradation by CMA may underpin the Lewy body pathology. Decreased CMA protein levels were not secondary to the various pathological changes associated with PD, including mitochondrial respiratory chain dysfunction, increased oxidative stress and proteasomal inhibition. However, decreased hsc70 and LAMP-2A protein levels in PD brains were associated with decreases in their respective mRNA levels. MicroRNA (miRNA) deregulation has been reported in PD brains and we have identified eight miRNAs predicted to regulate LAMP-2A or hsc70 expression that were reported to be increased in PD. Using a luciferase reporter assay in SH-SY5Y cells, four and three of these miRNAs significantly decreased luciferase activity expressed upstream of the lamp-2a and hsc70 3′UTR sequences respectively. We confirmed that transfection of these miRNAs also decreased endogenous LAMP-2A and hsc70 protein levels respectively and resulted in significant α-synuclein accumulation. The analysis of PD brains confirmed that six and two of these miRNAs were significantly increased in substantia nigra compacta and amygdala respectively. These data support the hypothesis that decreased CMA caused by miRNA-induced downregulation of CMA proteins plays an important role in the α-synuclein pathology associated with PD, and opens up a new avenue to investigate PD pathogenesis.     

Tolerance to low ambient calciumshows inter-population differences in Daphnia galeata

The tolerance to low ambient calcium (Ca) was assessed in twopopulations of Daphnia galeata. There was a threshold for survivalbetween 0 and 2 mg Ca l^-1. However, the ability to cope withlow Ca concentrations clearly differed between the two populations,as the population from the low-Ca locality was less tolerantto low Ca. Additionally, neonate individuals had poorer survivalthan adults when reared at ~0 mg Ca l^-1, supporting a suggestedjuvenile bottleneck regarding the tolerance to low Ca concentrations.The mean specific Ca content in adult D. galeata was not differentbetween the two populations, but individuals reared in mediumwith 1 mg Ca l^-1 only had two-thirds of the Ca content of thosereared in medium with 10 mg Ca l^-1. The significant differencesbetween the two populations investigated suggest that inter-populationvariation in tolerance to low ambient Ca concentrations mightbe important to explain the success of Ca-demanding crustaceansin softwater lakes.     

The costs of moulting in Daphnia; mineral regulation of carbon budgets

1. Zooplankton differ in their elemental contents. For the essential elements calcium (Ca) and phosphorus (P), Daphnia spp. have particularly high contents, and thus high demands, compared with other cladocera and copepods.
2. There are recent indications that the growth of zooplankton, notably Daphnia , may be directly constrained by the availability of P and Ca.
3. Major pools of P and Ca are associated with the carapace, and the moulting process represents a constant drain of these elements, as well as carbon (C), from the animals.
4. The demands for P and Ca for moulting may pose constraints on the carbon accumulation in the animals, and thus the extensive needs for these elements may translate into a total loss of C transported in the pelagic food web.
5. While the costs of moulting are substantial for the zooplankton, the export of minerals bound in the moult will play only a minor role for the epilimnetic element budgets in most lakes.
     

The Oral Commensal Streptococcus mitis Shows a Mixed Memory Th Cell Signature That Is Similar to and Cross-Reactive with Streptococcus pneumoniae

Background

Carriage of and infection with Streptococcus pneumoniae is known to predominantly induce T helper 17 (Th17) responses in humans, but the types of Th cells showing reactivity towards commensal streptococci with low pathogenic potential, such as the oral commensals S. mitis and S. salivarius, remain uncharacterized.

Methods

Memory CD4⁺ T helper (Th) cell subsets were isolated from healthy human blood donors according to differential expression of chemokine receptors, expanded in vitro using polyclonal stimuli and characterized for reactivity against different streptococcal strains.

Results

Th cells responding to S. mitis, S. salivarius and S. pneumoniae were predominantly in a CCR6⁺CXCR3⁺ subset and produced IFN-γ, and in a CCR6⁺CCR4⁺ subset and produced IL-17 and IL-22. Frequencies of S. pneumoniae-reactive Th cells were higher than frequencies of S. mitis- and S. salivarius-specific Th cells. S. mitis and S. pneumoniae isogenic capsule knock-out mutants and a S. mitis mutant expressing the serotype 4 capsule of S. pneumoniae showed no different Th cell responses as compared to wild type strains. S. mitis-specific Th17 cells showed cross-reactivity with S. pneumoniae.

Conclusions

As Th17 cells partly control clearance of S. pneumoniae, cross-reactive Th17 cells that may be induced by commensal bacterial species may influence the immune response, independent of capsule expression.     

Impact of proximal cytoplasmic droplets on quality traits and in-vitro embryo production efficiency of cryopreserved bull spermatozoa

Background  

Proximal cytoplasmic droplets (PCDs), a remnant of germ cell cytoplasm, are common non-specific morphological defects in bovine semen. This study evaluated the effect of higher percentages of PCDs on the quality of frozen-thawed bovine semen, embryo production and early embryo development.     

The environmental effectiveness of the beverage sector in Norway in a Factor 10 perspective

Scope and Background

The environmental effectiveness of the Norwegian beverage sector has been studied in a Factor 10 perspective. The objective of the study was to identify strategies that could make the beverage sector radically more effective from an environmental and resource perspective, leading to a Factor 10 improvement. Another main purpose of the work was to test the potential for using Life Cycle Assessment (LCA) methodology on an economic sector with a network of product chains, rather than for a single product.

Methods

Life Cycle Assessment data from STØ’s own studies and literature studies have been used as a basis for analysis of the environmental status of the beverage sector in Norway. The functional unit was defined as the amount of beverage products consumed per capita in Norway in the year 2000. The study includes raw material production, production of the beverage product, packaging manufacture, distribution, use and waste management of the products. The study has, for practical reasons, been limited to the environmental impact indicators total energy consumption and global warming potential. This was done as other types of data have been difficult to obtain for all of the products that were studied (tap water, coffee, milk, soft drinks, beer, squash, juice and bottled water).

Results and Discussion

The study shows differences between the drinking products with respect to energy consumption and emissions that can contribute to global warming. Due to large uncertainties in the data, general conclusions regarding the differentiation of products based on environmental performance should be made with care. Production and distribution of tap water is, however, significantly less energy intensive than the other products. For the impact categories studied, production of raw materials was the most important part of the life cycle for most drinking products.

Conclusions and Perspective

The most significant contributions to achieving a Factor 10 development can be made by consuming more water, especially tap water, and through improving raw material production in the agricultural sector. Packaging and distribution is responsible for only a small part of the energy consumption and emissions leading to global warming. Optimal packaging sizes might however reduce loss of products in the user phase, which is important in order to improve the system. A Factor 10 level seems achievable only if the consumption of tap water is increased to a high level.