The impact of CO2 emission scenarios and nutrient enrichment on a common coral reef macroalga is modified by temporal effects

Future coral reefs are expected to be subject to higher pCO₂ and temperature due to anthropogenic greenhouse gas emissions. Such global stressors are often paired with local stressors thereby potentially modifying the response of organisms. Benthic macroalgae are strong competitors to corals and are assumed to do well under future conditions. The present study aimed to assess the impact of past and future CO₂ emission scenarios as well as nutrient enrichment on the growth, productivity, pigment, and tissue nutrient content of the common tropical brown alga Chnoospora implexa. Two experiments were conducted to assess the differential impacts of the manipulated conditions in winter and spring. Chnoospora implexa's growth rate averaged over winter and spring declined with increasing pCO₂ and temperature. Furthermore, nutrient enrichment did not affect growth. Highest growth was observed under spring pre‐industrial (PI) conditions, while slightly reduced growth was observed under winter A1FI (“business‐as‐usual”) scenarios. Productivity was not a good proxy for growth, as net O₂ flux increased under A1FI conditions. Nutrient enrichment, whilst not affecting growth, led to luxury nutrient uptake that was greater in winter than in spring. The findings suggest that in contrast with previous work, C. implexa is not likely to show enhanced growth under future conditions in isolation or in conjunction with nutrient enrichment. Instead, the results suggest that greatest growth rates for this species appear to be a feature of the PI past, with A1FI winter conditions leading to potential decreases in the abundance of this species from present day levels.     

Targeting head and neck tumoral stem cells: From biological aspects to therapeutic perspectives

Head and neck squamous cell cancer(HNSCC) is the sixth most common cancer in the world. Effective therapeutic modalities such as surgery, radiation, chemotherapy and combinations of each are used in the management of the disease. In most cases, treatment fails to obtain total cancer cure. In recent years, it appears that one of the key determinants of treatment failure may be the presence of cancer stem cells(CSCs) that escape currently available therapies. CSCs form a small portion of the total tumor burden but may play a disproportionately important role in determining outcomes. CSCs have stem features such as self-renewal, high migration capacity, drug resistance, high proliferation abilities. A large body of evidence points to the fact that CSCs are particularly resistant to radiotherapy and chemotherapy. In HNSCC, CSCs have been increasingly shown to have an integral role in tumor initiation, disease progression, metastasis and treatment resistance. In the light of such observations, the present review summarizes biological characteristics of CSCs in HNSCC, outlines targeted strategies for the successful eradication of CSCs in HNSCC including targeting the self-renewal controlling pathways, blocking epithelial mesenchymal transition, niche targeting, immunotherapy approaches and highlights the need to better understand CSCs biology for new treatments modalities.     

Heliobacterium sulfidophilum sp. nov. andHeliobacterium undosum sp. nov.: Sulfideoxidizing heliobacteria from thermal sulfidic springs

Two new species of heliobacteria isolated from cyanobacterial mats of two alkaline sulfidic hot springs are formally described. Strains BR4 and BG29 are assigned to anoxygenic phototrophic bacteria of the familyHeliobacteriaceae, since they possess the unique properties of this taxon: strict anaerobiosis, formation of bacteriochlorophyllg, the lack of extensive intracytoplasmic membranes and chlorosomes, an unusual cell wall structure, and phylogenetic relatedness to the low G+C gram-positive eubacteria. Based on the 16S rDNA sequence similarity, strains BR4 and BG29 are assigned to the genusHeliobacterium and described as two new species of this genus:Heliobacterium sulfidophilum sp. nov. andHeliobacterium undosum sp. nov. The G+C content of the DNA is 51.3 mol % inHbt. sulfidophilum and 57.2-57.7 mol % inHbt. undosum. The cells ofHbt. sulfidophilum are rods, and the cells ofHbt. undosum are slightly twisted spirilla or short rods. Both new bacteria are motile by peritrichous flagella.Hbt. sulfidophilum produces endospores. The new bacteria are strict anaerobes growing photoheterotrophically on a limited range of organic compounds. In the dark, they can switch from photosynthesis to the slow fermentation of pyruvate. Biotin is required as a growth factor. Both species are highly tolerant to sulfide (up to 2 mM at pH 7.5) and oxidize it photoheterotrophically to elemental sulfur; photoautotrophic growth was not observed. The temperature optimal for growth ofHbt. sulfidophilum andHbt undosum is 30–35‡C, and the optimal pH is 7–8.     

Effect of vitamin concentration on the synthesis of lactate, ethanol, pyruvate, and ethyl acetate in cells of the yeast Dipodascus magnusii

In the yeast Dipodascus magnusii, which is auxotrophic for thiamine and biotin, during cultivation on glucose with excessive thiamine concentration, pyruvate metabolism was shown to result in the synthesis of fermentation products, namely, ethanol and, to a lesser extent, lactate. Substantial synthesis of ethyl acetate was also observed under these conditions. Introduction of nicotinic acid (NA) into the medium resulted in time separation of ethanol and lactate production. It was shown that cultivation of the yeast under biotin deficiency resulted in nearly complete suppression of aerobic production of ethanol and cessation of ethyl acetate synthesis, whereas lactate synthesis was activated as early as in the first hours of cultivation. Upon introduction of NA under these conditions, lactate concentration sharply increased. These results show that the combination of thiamine and biotin with other vitamins can stimulate utilization of the pyruvate pool in yeasts towards formation of considerable amounts of lactate, which is typical only of cells of higher eukaryotes and bacteria.     

Tailoring Absorption in Metal Gratings with Resonant Ultrathin Bridges

We present a theoretical analysis of the effects of short range surface plasmon polariton excitation on subwavelength bridges in metal gratings. We show that localized resonances in thin metal bridges placed within the slit of a free-standing silver grating dramatically modify transmission spectra and boost absorption regardless of the periodicity of the grating. Additionally, the interference of multiple localized resonances makes it possible to tailor the absorption properties of ultrathin gratings, regardless of the apertures’ geometrical size. This tunable, narrow band, enhanced–absorption mechanism triggered by resonant, short-range surface plasmon polaritons may also enhance nonlinear optical processes like harmonic generation, in view of the large third-order susceptibility of metals.     

CO<Subscript>2</Subscript> exchange and structural organization of chloroplasts under hypothermia in potato plants transformed with a gene for yeast invertase

Growth, CO₂ exchange, and the ultrastructure of chloroplasts were investigated in the leaves of potato plants (Solanum tuberosum L., cv. Désirée) of wild type and transformed with a gene for yeast invertase under the control of patatin class I B33 promoter (for apoplastic enzyme) grown in vitro on the Murashige and Skoog medium supplemented with 2% sucrose. At a temperature of 22°C optimal for growth, the transformed plants differed from the plants of wild type in retarded growth and a lower rate of photosynthesis as calculated per plant. On a leaf dry weight basis, photosynthesis of transformed plants was higher than in control plants. Under hypothermia (5°C), dark respiration and especially photosynthesis of transformed plants turned out to be more intense than in control material. After a prolonged exposure to low temperature (6 days at 5°C), in the plants of both genotypes, the ultrastructure of chloroplasts changed. Absolute areas of sections of chloroplasts and starch grains rose, and the area of plastoglobules decreased; in transformed plants, these changes were more pronounced. By some ultrastructural characteristics: a reduction in the cold of relative total area of sections of starch grains and plastoglobules (in percents of the chloroplast section area) and in the number of granal thylakoids (per a chloroplast section area), transformed plants turned out to be more cold resistant than wild-type plants. The obtained results are discussed in connection with changes in source-sink relations in transformed potato plants. These changes modify the balance between photosynthesis and retarded efflux of assimilates, causing an increase in the intracellular level of sugars and a rise in the tolerance to chilling.     

Lipolysis drives expression of the constitutively active receptor GPR3 to induce adipose thermogenesis

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Replication and fine mapping of asthma-associated loci in individuals of African ancestry

Asthma originates from genetic and environmental factors with about half the risk of disease attributable to heritable causes. Genome-wide association studies, mostly in populations of European ancestry, have identified numerous asthma-associated single nucleotide polymorphisms (SNPs). Studies in populations with diverse ancestries allow both for identification of robust associations that replicate across ethnic groups and for improved resolution of associated loci due to different patterns of linkage disequilibrium between ethnic groups. Here we report on an analysis of 745 African-American subjects with asthma and 3,238 African-American control subjects from the Candidate Gene Association Resource (CARe) Consortium, including analysis of SNPs imputed using 1,000 Genomes reference panels and adjustment for local ancestry. We show strong evidence that variation near RAD50/IL13, implicated in studies of European ancestry individuals, replicates in individuals largely of African ancestry. Fine mapping in African ancestry populations also refined the variants of interest for this association. We also provide strong or nominal evidence of replication at loci near ORMDL3/GSDMB, IL1RL1/IL18R1, and 10p14, all previously associated with asthma in European or Japanese populations, but not at the PYHIN1 locus previously reported in studies of African-American samples. These results improve the understanding of asthma genetics and further demonstrate the utility of genetic studies in populations other than those of largely European ancestry.