The induction of inflammation by dectin-1 in vivo is dependent on myeloid cell programming and the progression of phagocytosis

Dectin-1 is the archetypal signaling, non-Toll-like pattern recognition receptor that plays a protective role in immune defense to Candida albicans as the major leukocyte receptor for beta-glucans. Dectin-1-deficiency is associated with impaired recruitment of inflammatory leukocytes and inflammatory mediator production at the site of infection. In this study, we have used mice to define the mechanisms that regulate the dectin-1-mediated inflammatory responses. Myeloid cell activation by dectin-1 is controlled by inherent cellular programming, with distinct macrophage and dendritic cell populations responding differentially to the engagement of this receptor. The inflammatory response is further modulated by the progression of the phagocytosis, with "frustrated phagocytosis" resulting in dramatically augmented inflammatory responses. These studies demonstrate that dectin-1 in isolation is sufficient to drive a potent inflammatory response in a context-dependent manner. This has implications for the mechanism by which myeloid cells are activated during fungal infections and the processes involved in the therapeutic manipulation of the immune system via exogenous dectin-1 stimulation or blockade.     

Opposing effects of floral visitors and soil conditions on the determinants of competitive outcomes maintain species diversity in heterogeneous landscapes

Theory argues that both soil conditions and aboveground trophic interactions have equivalent potential to limit or promote plant diversity. However, it remains unexplored how they jointly modify the niche differences stabilising species coexistence and the average fitness differences driving competitive dominance. We conducted a field study in Mediterranean annual grasslands to parameterise population models of six competing plant species. Spatially explicit floral visitor assemblages and soil salinity variation were characterised for each species. Both floral visitors and soil salinity modified species population dynamics via direct changes in seed production and indirect changes in competitive responses. Although the magnitude and sign of these changes were species‐specific, floral visitors promoted coexistence at neighbourhood scales, while soil salinity did so over larger scales by changing the superior competitors’ identity. Our results show how below and aboveground interactions maintain diversity in heterogeneous landscapes through their opposing effects on the determinants of competitive outcomes.     

Novel Surface Display System for Proteins on Non-Genetically Modified Gram-Positive Bacteria

A novel display system is described that allows highly efficient immobilization of heterologous proteins on bacterial surfaces in applications for which the use of genetically modified bacteria is less desirable. This system is based on nonliving and non-genetically modified gram-positive bacterial cells, designated gram-positive enhancer matrix (GEM) particles, which are used as substrates to bind externally added heterologous proteins by means of a high-affinity binding domain. This binding domain, the protein anchor (PA), was derived from the Lactococcus lactis peptidoglycan hydrolase AcmA. GEM particles were typically prepared from the innocuous bacterium L. lactis, and various parameters for the optimal preparation of GEM particles and binding of PA fusion proteins were determined. The versatility and flexibility of the display and delivery technology were demonstrated by investigating enzyme immobilization and nasal vaccine applications.     

Potentially handicapped but otherwise functional: Malformations in prey capture tools show no impacts on octopus life

Larval mortality is a keystone ecological factor for many benthic octopus since it mostly occurs before their settlement in the sea bottom as benthic juveniles. The literature had revealed that records of adult animals with morphological abnormalities (teratologies) are fewer in species with complex life cycle than in those with direct development. This is a direct consequence of the morphological, physiological, and development challenges that the transition from the larval to the adult morphology represents. During a routine fishing sample, we found an immature female horned octopus with additional buccal structures in two suckers of its ventral arms, likely rendering these suckers as inefficient. Based on the literature about the natural history of octopus, we provide evidence that these abnormalities were present at the moment of hatch. We evaluated the impact of the teratologies by comparing the shape of the buccal beaks and the trophic niche of the individual with five normal conspecifics. Although the beaks showed a different shape than normal individuals, the trophic niche was similar. Surprisingly, the teratological condition of the individual likely had no severe impacts on its life, even though it likely represents a handicap for its survival during its planktonic life. We also comment on other previous records from the literature of teratological adult octopus to highlight the amazing adaptive capacity of octopus to deal with challenging morphologies.     

Amberlite IRA 900 versus calcium alginate in immobilization of a novel,engineered β-fructofuranosidase for short-chain fructooligosaccharide synthesis from sucrose

The immobilization of β-fructofuranosidase for short-chain fructooligosaccharide (scFOS) synthesis holds the potential for a more efficient use of the biocatalyst. However, the choice of carrier and immobilization technique is a key to achieving that efficiency. In this study, calcium alginate (CA), Amberlite IRA 900 (AI900) and Dowex Marathon MSA (DMM) were tested as supports for immobilizing a novel engineered β-fructofuranosidase from Aspergillus japonicus for scFOS synthesis. Several immobilization parameters were estimated to ascertain the effectiveness of the carriers in immobilizing the enzyme. The performance of the immobilized biocatalysts are compared in terms of the yield of scFOS produced and reusability. The selection of carriers and reagents was motivated by the need to ensure safety of application in the production of food-grade products. The CA and AI900 both recorded impressive immobilization yields of 82 and 62%, respectively, while the DMM recorded 47%. Enzyme immobilizations on CA, AI900 and DMM showed activity recoveries of 23, 27, and 17%, respectively. The CA, AI900 immobilized and the free enzymes recorded their highest scFOS yields of 59, 53, and 61%, respectively. The AI900 immobilized enzyme produced a consistent scFOS yield and composition for 12 batch cycles but for the CA immobilized enzyme, only 6 batch cycles gave a consistent scFOS yield. In its first record of application in scFOS production, the AI900 anion exchange resin exhibited potential as an adequate carrier for industrial application with possible savings on cost of immobilization and reduced technical difficulty.     

Do changes in climate patterns in wintering areas affect the timing of the spring arrival of trans‐Saharan migrant birds?

The life cycles of plants and animals are changing around the world in line with the predictions originated from hypotheses concerning the impact of global warming and climate change on biological systems. Commonly, the search for ecological mechanisms behind the observed changes in bird phenology has focused on the analysis of climatic patterns from the species breeding grounds. However, the ecology of bird migration suggests that the spring arrival of long‐distance migrants (such as trans‐Saharan birds) is more likely to be influenced by climate conditions in wintering areas given their direct impact on the onset of migration and its progression. We tested this hypothesis by analysing the first arrival dates (FADs) of six trans‐Saharan migrants (cuckoo Cuculus canorus, swift Apus apus, hoopoe Upupa epops, swallow Hirundo rustica, house martin Delichon urbica and nightingale Luscinia megarhynchos), in a western Mediterranean area since from 1952 to 2003. By means of multiple regression analyses, FADs were analysed in relation to the monthly temperature and precipitation patterns of five African climatic regions south of the Sahara where species are thought to overwinter and from the European site from where FADs were collected. We obtained significant models for five species explaining 9–41% of the variation in FADs. The interpretation of the models suggests that: (1) The climate in wintering quarters, especially the precipitation, has a stronger influence on FADs than that in the species' potential European breeding grounds. (2) The accumulative effects of climate patterns prior to migration onset may be of considerable importance since those climate variables that served to summarize climate patterns 12 months prior to the onset of migration were selected by final models. (3) Temperature and precipitation in African regions are likely to affect departure decision in the species studied through their indirect effects on food availability and the build‐up of reserves for migration. Our results concerning the factors that affect the arrival times of trans‐Saharan migrants indicate that the effects of climate change are more complex than previously suggested, and that these effects might have an interacting impact on species ecology, for example by reversing ecological pressures during species' life cycles.     

The response of stream periphyton to Pacific salmon: using a model to understand the role of environmental context

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Lithium treatment induces a hypersensitive-like response in tobacco

Treatment of tobacco ( Nicotiana tabacum L.) plants with lithium induces the formation of necrotic lesions and leaf curling as in the case of incompatible pathogen interactions. Further similarities at the molecular level include accumulation of ethylene and of salicylic and gentisic acids, and induced expression of pathogenesis-related PR-P, PR5 and PR1 genes. With the exception of PR1 induction, lithium produced the same effects in transgenic tobacco plants that do not accumulate salicylate because of overexpression of the bacterial hydroxylase gene nahG. On the other hand, inhibition of ethylene biosynthesis with aminoethoxyvinylglycine prevented lithium-induced cell death and PR5 expression. These results suggest that lithium triggers a hypersensitive-like response where ethylene signalling is essential.     

Metabolic engineering of isoprenoid biosynthesis in Arabidopsis for the production of taxadiene, the first committed precursor of Taxol

Paclitaxel (Taxol) is a widely used anticancer isoprenoid produced by the secondary metabolism of yew (Taxus sp.) trees. However, only limited amounts of Taxol or related metabolites (taxoids) can be obtained from the currently available sources. In this work we have taken the first step toward genetically engineering the biosynthesis of taxoids in angiosperms. The first committed step in Taxol biosynthesis is the production of taxadiene from geranylgeranyl diphosphate (GGPP), catalyzed by the plastid-localized enzyme taxadiene synthase (TXS). A recombinant T. baccata TXS lacking the putative plastid targeting peptide and fused to a C-terminal histidine (His) tag was shown to be enzymatically active in Escherichia coli. Constitutive production of the full-length His-tagged enzyme in Arabidopsis thaliana plants led to the accumulation of taxadiene and concomitant growth retardation and decreased levels of photosynthetic pigment in transgenic plants. Although these phenotypes may derive from a toxic effect of taxadiene, the lower accumulation of endogenous plastid isoprenoid products such as carotenoids and chlorophylls in transgenic plants also suggests that the constitutive production of an active TXS enzyme might alter the balance of the GGPP pool. Induction of transgene expression using a glucocorticoid-mediated system consistently resulted in a more efficient recruitment of GGPP for the production of taxadiene, which reached levels 30-fold higher than those in plants constitutively expressing the transgene. This accomplishment illustrates the possibility of engineering the production of taxoids and other GGPP-derived isoprenoids in crop plants despite the constraints associated with limited knowledge with regard to regulation of GGPP availability.