Maximum Photosynthetic Yield of Green Microalgae in Photobioreactors

The biomass yield on light energy of Dunaliella tertiolecta and Chlorella sorokiniana was investigated in a 1.25- and 2.15-cm light path panel photobioreactor at constant ingoing photon flux density (930 µmol photons m−2 s−1). At the optimal combination of biomass density and dilution rate, equal biomass yields on light energy were observed for both light paths for both microalgae. The observed biomass yield on light energy appeared to be based on a constant intrinsic biomass yield and a constant maintenance energy requirement per gram biomass. Using the model of Pirt (New Phytol 102:3–37, 1986), a biomass yield on light energy of 0.78 and 0.75 g mol photons−1 and a maintenance requirement of 0.0133 and 0.0068 mol photons g−1 h−1 were found for D. tertiolecta and C. sorokiniana, respectively. The observed yield decreases steeply at low light supply rates, and according to this model, this is related to the increase of the amount of useable light energy diverted to biomass maintenance. With this study, we demonstrated that the observed biomass yield on light in short light path bioreactors at high biomass densities decreases because maintenance requirements are relatively high at these conditions. All our experimental data for the two strains tested could be described by the physiological models of Pirt (New Phytol 102:3–37, 1986). Consequently, for the design of a photobioreactor, we should maintain a relatively high specific light supply rate. A process with high biomass densities and high yields at high light intensities can only be obtained in short light path photobioreactors

Pharmacological Aspects of Vipera xantina palestinae Venom

In Israel, Vipera xantina palestinae (V.x.p.) is the most common venomous snake, accounting for several hundred cases of envenomation in humans and domestic animals every year, with a mortality rate of 0.5 to 2%. In this review we will briefly address the research developments relevant to our present understanding of the structure and function of V.x.p. venom with emphasis on venom disintegrins. Venom proteomics indicated the presence of four families of pharmacologically active compounds: (i) neurotoxins; (ii) hemorrhagins; (iii) angioneurin growth factors; and (iv) different types of integrin inhibitors. Viperistatin, a α1β1selective KTS disintegrin and VP12, a α2β1 selective C-type lectin were discovered. These snake venom proteins represent promising tools for research and development of novel collagen receptor selective drugs. These discoveries are also relevant for future improvement of antivenom therapy towards V.x.p. envenomation

Bacterial Distribution in the Rhizosphere of Wild Barley under Contrasting Microclimates

Background: All plants in nature harbor a diverse community of rhizosphere bacteria which can affect the plant growth. Our samples are isolated from the rhizosphere of wild barley Hordeum spontaneum at the Evolution Canyon (‘EC’), Israel. The bacteria which have been living in close relationship with the plant root under the stressful conditions over millennia are likely to have developed strategies to alleviate plant stress. Methodology/Principal Findings: We studied distribution of culturable bacteria in the rhizosphere of H. spontaneum and characterized the bacterial 1-aminocyclopropane-1-carboxylate deaminase (ACCd) production, biofilm production, phosphorus solubilization and halophilic behavior. We have shown that the H. spontaneum rhizosphere at the stressful South Facing Slope (SFS) harbors significantly higher population of ACCd producing biofilm forming phosphorus solubilizing osmotic stress tolerant bacteria. Conclusions/Significance: The long-lived natural laboratory ‘EC ’ facilitates the generation of theoretical testable and predictable models of biodiversity and genome evolution on the area of plant microbe interactions. It is likely that the bacteria isolated at the stressful SFS offer new opportunities for the biotechnological applications in our agro-ecologica

Assessing the potential for sea-based macroalgae cultivation and its application for nutrient removal in the Baltic Sea

Marine eutrophication is a pervasive and growing threat to global sustainability. Macroalgal cultivation is a promising circular economy solution to achieve nutrient reduction and food security. However, the location of production hotspots is not well known. In this paper the production potential of macroalgae of high commercial value was predicted across the Baltic Sea region. In addition, the nutrient limitation within and adjacent to macroalgal farms was investigated to suggest optimal site-specific configuration of farms. The production potential of Saccharina latissima was largely driven by salinity and the highest production yields are expected in the westernmost Baltic Sea areas where salinity is >23. The direct and interactive effects of light availability, temperature, salinity and nutrient concentrations regulated the predicted changes in the production of Ulva intestinalis and Fucus vesiculosus. The western and southern Baltic Sea exhibited the highest farming potential for these species, with promising areas also in the eastern Baltic Sea. Macroalgal farming did not induce significant nutrient limitation. The expected spatial propagation of nutrient limitation caused by macroalgal farming was less than 100–250 m. Higher propagation distances were found in areas of low nutrient and low water exchange (e.g. offshore areas in the Baltic Proper) and smaller distances in areas of high nutrient and high water exchange (e.g. western Baltic Sea and Gulf of Riga). The generated maps provide the most sought-after input to support blue growth initiatives that foster the sustainable development of macroalgal cultivation and reduction of in situ nutrient loads in the Baltic Sea.</p

Density dependent growth of the red algae Furcellaria lumbricalis and Coccotylus trancatus in the West Estonian Archipelago Sea, Northern Baltic Sea

In an in situ experiment we evaluated the growth of the red algae Furcellaria lumbricalis and Coccotylus truncatus in the Archipelago Sea. The results showed that the growth rates of both species were similar but that growth decreased with increasing algal coverage. The effects were more pronounced for C. truncatus than for F. lumbricalis. Economic analyses aiming to establish sustainable harvesting limits for F. lumbricalis in the study area should take account of the density dependent growth of these red algae

RGS16 restricts the pro-inflammatory response of monocytes.

International audienceImmune cells express powerful and harmful effectors that require tight regulation. Heterotrimeric G proteins are critical mediators in translating extracellular signals into cell responses, which need a fine-tuned regulation for the control of cell activation. Regulator of G-protein signalling 16 (RGS16) has been identified as a key factor of G protein-mediated activation in lymphocytes, modulating inflammatory and survival responses of various cell types. However, data about the expression of this regulatory protein in monocytes are scarce, and it has remained unclear whether activation and migration of these cells are regulated by RGS16. In this study, the impact of RGS16 on the production of inflammatory cytokines by activated human monocytes was investigated in vitro using the human promonocytic cell line THP-1 as a model. Gain and loss of function experiments showed that RGS16 overexpression reduces the expression of pro-inflammatory cytokines IL-1β, IL-6, IL-8 and TNFα, while RGS16 knockdown by RNAi upregulates IL-1β, IL-6 and TNFα but not IL-8. RGS16 knockdown was also shown to enhance Pam3-mediated induction of the anti-inflammatory cytokine IL-10. Our results indicate that RGS16 restricts the activation-induced pro-inflammatory profile in myeloid cells