Marine sponges (Porifera) from the Bahía San Antonio (North Patagonian Gulfs,Argentina), with additions to the phylogeography of the widely distributed Cliona aff. celata and Hymeniacidon perlevis,and the description of two new species

Six sponge species from Bahía San Antonio (north Argentinean Patagonia) are (re)described, including two new species, namely Halichondria (Halichondria) elenae sp. nov. and Clathria (Microciona) saoensis sp. nov., and three new records for the Argentinean coast. Halichondria (H.) elenae sp. nov. is the only yellowish-greenish SW Atlantic Halichondria with oxeas up to 450?µm. The new species’ 18S rRNA blasted with Halichondria bowerbanki from Ireland, but it is argued that co-specificity is unlikely, in view of their rather distinct morphologies. Clathria (M.) saoensis sp. nov. is the only C. (Microciona) in the SW Atlantic, SE Pacific, and (sub)Antarctic regions with smooth (or nearly so) principal megascleres, mostly below 500?µm long, as well as moderately curved toxas, and isochelae of regular non-cleistochelate shape. Cliona aff. celata and Hymeniacidon perlevis had their identifications confirmed by the sequencing of their 28S and 18S rRNA genes, respectively, and mitochondrial CO1. Both of them clustered with previously sequenced specimens from the Temperate North Atlantic, apart from additional samples from SE Brazil, in the case of C. aff. celata, and China and South Korea, in the case of H. perlevis.     

Understanding the properties of aerobic sludge granules as hydrogels

Aerobic sludge granules are larger, denser microbial aggregates than activated sludge flocs with a smoother and more regular surface, which facilitates greater wastewater treatment intensity. Factors important in their growth are still poorly understood, which is an impediment to the construction and operation of full-scale aerobic sludge granule processes. Data in this article obtained with granules treating an abattoir wastewater provide evidence that aerobic sludge granules are hydrogels. The results also demonstrate a method for characterizing macromolecular associations. The rheological profile of these granules was found to be analogous with that of typical polymer gels. Water uptake or swelling reflects an equilibrium between granule elastic modulus and osmotic pressure, whereby uptake is increased by reducing solute concentration or the elastic modulus. A weakening of the extracellular polymeric substance (EPS) matrix as demonstrated with mechanical spectroscopy was induced by several environmental factors including temperature, pH and ionic strength. Uniform and elastic deformation was observed at low strain. Enzymatic degradation studies indicate that proteins and alpha-polysaccharides were the major granule structural materials. The aerobic sludge granules in the current study were therefore protein-polysaccharide composite physical hydrogels. While aerobic sludge granules treating an abattoir wastewater are used as a case study, many of the fundamental principles detailed here are relevant to other granulation processes. The paradigm established in this study can potentially be applied to better understand the formation of aerobic sludge granules and thus overcome a hurdle in the acceptance of aerobic sludge granulation as an alternative to more traditional wastewater treatment processes.     

KSHV latent protein LANA2 inhibits sumo2 modification of p53

Tumor suppressor p53 plays a crucial antiviral role and targeting of p53 by viral proteins is a common mechanism involved in virus oncogenesis. The activity of p53 is tightly regulated at the post-translational levels through a myriad of modifications. Among them, modification of p53 by SUMO has been associated with the onset of cellular senescence. Kaposi´s sarcoma-associated herpesvirus (KSHV) expresses several proteins targeting p53, including the latent protein LANA2 that regulates polyubiquitylation and phosphorylation of p53. Here we show that LANA2 also inhibits the modification of p53 by SUMO2. Furthermore, we show that the reduction of p53-SUMO2 conjugation by LANA2, as well as the p53-LANA2 interaction, both require the SUMOylation of the viral protein and its interaction with SUMO or SUMOylated proteins in a non-covalent manner. Finally, we show that the control of p53-SUMO2 conjugation by LANA2 correlates with its ability to inhibit SUMO2- and type I interferon-induced senescence. These results highlight the importance of p53 SUMOylation in the control of virus infection and suggest that viral oncoproteins could contribute to viral infection and cell transformation by abrogating p53 SUMOylation.     

Net P-removal deterioration in enriched PAO sludge subjected to permanent aerobic conditions

Recently, some research in the field of enhanced biological phosphorus removal (EBPR) has been focused on studying systems where the electron donor (substrate) and the electron acceptor (nitrate or oxygen) are present simultaneously. This can occur, for example, in a full scale wastewater treatment plant during heavy rainfall periods when the anaerobic hydraulic retention time is temporarily shortened. To study this situation that could induce EBPR failure, the operation of a sequencing batch reactor (SBR) working under alternating anaerobic-aerobic conditions with an enriched EBPR population (50% Candidatus Accumulibacter phosphatis and less than 1% Candidatus Competibacter phosphatis) was shifted to strict aerobic operation. Seven cycle studies were performed during the 11 days of aerobic operation. Net P-removal was observed in this aerobic SBR during the first 4 days of operation but the system could not achieve net-P removal after this period, although the microbial composition, in terms of percentage of Accumulibacter and Competibacter, did not change significantly. The observed changes in the different compounds analysed (phosphorus, acetate, glycogen and PHB) as well as in the OUR profile indicate that metabolic changes are produced for the adaptation of PAO to aerobic conditions.     

Hydrocarbons Are Essential for Optimal Cell Size,Division, and Growth of Cyanobacteria

Cyanobacteria are intricately organized, incorporating an array of internal thylakoid membranes, the site of photosynthesis, into cells no larger than other bacteria. They also synthesize C15-C19 alkanes and alkenes, which results in substantial production of hydrocarbons in the environment. All sequenced cyanobacteria encode hydrocarbon biosynthesis pathways, suggesting an important, undefined physiological role for these compounds. Here, we demonstrate that hydrocarbon-deficient mutants of Synechococcus sp. PCC 7002 and Synechocystis sp. PCC 6803 exhibit significant phenotypic differences from wild type, including enlarged cell size, reduced growth, and increased division defects. Photosynthetic rates were similar between strains, although a minor reduction in energy transfer between the soluble light harvesting phycobilisome complex and membrane-bound photosystems was observed. Hydrocarbons were shown to accumulate in thylakoid and cytoplasmic membranes. Modeling of membranes suggests these compounds aggregate in the center of the lipid bilayer, potentially promoting membrane flexibility and facilitating curvature. In vivo measurements confirmed that Synechococcus sp. PCC 7002 mutants lacking hydrocarbons exhibit reduced thylakoid membrane curvature compared to wild type. We propose that hydrocarbons may have a role in inducing the flexibility in membranes required for optimal cell division, size, and growth, and efficient association of soluble and membrane bound proteins. The recent identification of C15-C17 alkanes and alkenes in microalgal species suggests hydrocarbons may serve a similar function in a broad range of photosynthetic organisms.Cyanobacteria (oxygenic photosynthetic bacteria) are found in nearly every environment on Earth and are major contributors to global carbon and nitrogen fixation (Galloway et al., 2004; Zwirglmaier et al., 2008). They are distinguished among prokaryotes in containing multiple internal thylakoid membranes, the site of photosynthesis, and a large protein compartment, the carboxysome, involved in carbon fixation. Despite these extra features, cyanobacteria can be as small as 0.6 µm in diameter (Raven, 1998).All cyanobacteria with sequenced genomes encode the pathway for the biosynthesis of hydrocarbons, implying an important, although as-yet-undefined, role for these compounds (Lea-Smith et al., 2015). The major forms are C15-C19 alkanes and alkenes, which can be synthesized from fatty acyl-acyl-carrier proteins (ACPs) by one or other of two separate pathways (Fig. 1; Schirmer et al., 2010; Mendez-Perez et al., 2011). The majority of species produce alkanes and alkenes via acyl-ACP reductase (FAR) and aldehyde deformylating oxygenase (FAD; Schirmer et al., 2010; Li et al., 2012; Coates et al., 2014; Lea-Smith et al., 2015). Cyanobacterial species lacking the FAR/FAD pathway synthesize alkenes via olefin synthase (Ols; Mendez-Perez et al., 2011; Coates et al., 2014; Lea-Smith et al., 2015). This suggests that hydrocarbons produced by either pathway serve a similar role in the cell. Homologs of FAR/FAD or Ols are not present in other bacteria or plant and algal species. However, C15-C17 alkanes and alkenes, synthesized by an alternate, uncharacterized pathway, were recently detected in a range of green microalgae, including Chlamydomonas reinhardtii, Chlorella variabilis NC64A, and several Nannochloropsis species (Sorigué et al., 2016). In C. reinhardtii, hydrocarbons were primarily localized to the chloroplast, which originated in evolution from a cyanobacterium that was engulfed by a host organism (Howe et al., 2008). Hydrocarbons may therefore have a similar role in cyanobacteria, some green microalgae species, and possibly a broader range of photosynthetic organisms.Open in a separate windowFigure 1.Hydrocarbon biosynthesis is encoded in all sequenced cyanobacteria. Detailed are the two hydrocarbon biosynthetic pathways, indicated in blue and red, respectively, in cyanobacteria. The number of species encoding the enzymes in each pathway is indicated.Hydrocarbons act as antidesiccants, waterproofing agents, and signaling molecules in insects (Howard and Blomquist, 2005) and prevent water loss, ensure pollen viability, and influence pathogen interactions in plants (Kosma et al., 2009; Bourdenx et al., 2011). However, the function of hydrocarbons in cyanobacteria has not been determined. Characterization of cyanobacterial hydrocarbon biosynthesis pathways has provided the basis for investigating synthetic microbial biofuel systems, which may be a renewable substitute for fossil fuels (Schirmer et al., 2010; Choi and Lee, 2013; Howard et al., 2013). However, secretion of long-chain hydrocarbons from the cell into the medium, which is likely essential for commercially viable production, has not been observed in the absence of a membrane solubilization agent (Schirmer et al., 2010; Tan et al., 2011). Cyanobacterial hydrocarbons also have a significant environmental role. Due to the abundance of cyanobacteria in the environment, hydrocarbon production is considerable, with hundreds of millions of tons released into the ocean per annum following cell death (Lea-Smith et al., 2015). This production may be sufficient to sustain populations of hydrocarbon-degrading bacteria, which can then play an important role in consuming anthropogenic oil spills (Lea-Smith et al., 2015).Here, we investigated the cellular location and role of hydrocarbons in both spherical Synechocystis sp. PCC 6803 (Synechocystis) and rod-shaped Synechococcus sp. PCC 7002 (Synechococcus) cells. We developed a model of the cyanobacterial membrane, which indicated that hydrocarbons aggregate in the middle of the lipid bilayer and, when present at levels observed in cells, lead to membrane swelling associated with pools of hydrocarbon. This suggested that alkanes may facilitate membrane curvature. In vivo measurements of Synechococcus thylakoid membrane conformation are consistent with this model.     

Household Transmission of Influenza A(H1N1)pdm09 in the Pandemic and Post-Pandemic Seasons

Background

The transmission of influenza viruses occurs person to person and is facilitated by contacts within enclosed environments such as households. The aim of this study was to evaluate secondary attack rates and factors associated with household transmission of laboratory-confirmed influenza A(H1N1)pdm09 in the pandemic and post-pandemic seasons.

Methods

During the 2009–2010 and 2010–2011 influenza seasons, 76 sentinel physicians in Navarra, Spain, took nasopharyngeal and pharyngeal swabs from patients diagnosed with influenza-like illness. A trained nurse telephoned households of those patients who were laboratory-confirmed for influenza A(H1N1)pdm09 to ask about the symptoms, risk factors and vaccination status of each household member.

Results

In the 405 households with a patient laboratory-confirmed for influenza A(H1N1)pdm09, 977 susceptible contacts were identified; 16% of them (95% CI 14–19%) presented influenza-like illness and were considered as secondary cases. The secondary attack rate was 14% in 2009–2010 and 19% in the 2010–2011 season (p = 0.049), an increase that mainly affected persons with major chronic conditions. In the multivariate logistic regression analysis, the risk of being a secondary case was higher in the 2010–2011 season than in the 2009–2010 season (adjusted odds ratio: 1.72; 95% CI 1.17–2.54), and in children under 5 years, with a decreasing risk in older contacts. Influenza vaccination was associated with lesser incidence of influenza-like illness near to statistical significance (adjusted odds ratio: 0.29; 95% CI 0.08–1.03).

Conclusion

The secondary attack rate in households was higher in the second season than in the first pandemic season. Children had a greater risk of infection. Preventive measures should be maintained in the second pandemic season, especially in high-risk persons.     

Effect of temperature and starvation upon survival strategies of Pseudomonas fluorescens CHA0: comparison with Escherichia coli

Microorganisms in aquatic systems are exposed to continuous modifications in their environmental conditions. In these systems, both autochthonous and allochthonous bacteria respond to adverse conditions by expressing viable but nonculturable phenotype. On the basis of this common response, the behaviour of a few species is extrapolated to others. We compared the survival strategies of Escherichia coli (allochthonous, mesophile bacterium) and Pseudomonas fluorescens CHA0 (ubiquitous, psychrotrophic bacteria) under nonoptimal temperature and nutrient deprivation. In the absence of nutrients, the effect of temperature on the loss of culturability did not show a common pattern. Whereas the survival of E. coli had an inverse relationship with temperature, whereas for P. fluorescens a direct relationship between temperature and T?? values was only established in the range 5-15°C, with an inverse relationship at higher temperatures. When the subproteome of the outer membrane of P. fluorescens was comparatively analysed, starvation was not the main source of change. The most relevant modifications were due to variations in temperature. OprF, the major surface protein of the genus Pseudomonas, showed a high expression in nonculturable as well as culturable populations under all the adverse situations analysed. We therefore propose OprF as a suitable marker for Pseudomonas detection in the environment.     

Cytokine Stimulation Promotes Increased Glucose Uptake Via Translocation at the Plasma Membrane of GLUT1 in HEK293 Cells

Interleukin‐3 (IL‐3) and granulocyte/macrophage colony‐stimulating factor (GM‐CSF) are two of the best‐characterized cell survival factors in hematopoietic cells; these factors induce an increase in Akt activity in multiple cell lines, a process thought to be involved in cellular survival. It is known that growth factors require sustained glucose metabolism to promote cell survival. It has been determined that IL‐3 and GM‐CSF signal for increased glucose uptake in hematopoietic cells. Interestingly, receptors for IL‐3 and GM‐CSF are present in several non‐hematopoietic cell types but their roles in these cells have been poorly described. In this study, we demonstrated the expression of IL‐3 and GM‐CSF receptors in HEK293 cells and analyzed their effect on glucose uptake. In these cells, both IL‐3 and GM‐CSF, increased glucose uptake. The results indicated that this increase involves the subcellular redistribution of GLUT1, affecting glucose transporter levels at the cell surface in HEK293 cells. Also the data directly demonstrates that the PI 3‐kinase/Akt pathway is an important mediator of this process. Altogether these results show a role for non‐insulin growth factors in the regulation of GLUT1 trafficking that has not yet been directly determined in non‐hematopoietic cells. J. Cell. Biochem. 110: 1471–1480, 2010. © 2010 Wiley‐Liss, Inc.