Seasonal phosphorus dynamics in the surficial sediment of two shallow temperate lakes: a solid-phase and pore-water study

This study examined phosphorus (P) dynamics by surveying the solid-phase and pore-water of the surficial sediment in a mesotrophic and eutrophic shallow lake in Maine, USA. Both lakes were dimictic, developed hypolimnetic anoxia, and released sedimentary P. We examined the controls on sedimentary P release by considering two possible mechanisms; mineralization and release of sedimentary organic P, and dissolution of Fe hydroxide following the onset of anoxia. The temporal investigation of solid-phase included sequential chemical extraction and ³¹P NMR analysis, and the pore-water included use of equilibrium samplers. In both lakes, the relative contribution of organic P to total sedimentary P release was minor compared to Fe hydroxide-associated P. The eutrophic lake, however, had more evidence of microbial uptake of sedimentary P and a higher degree of rapid P transformation in the water column. Sediment polyphosphates were dynamic and possibly contributed to hypolimnetic P accumulation. The pore-water Fe and P profiles exhibited similar temporal patterns as the solid-phase results. Together, they showed an upward migration of the redoxcline in the sediment, from winter to summer, resulting in the accumulation of Fe-bound P at the sediment?Cwater interface in the winter followed by its release into the summer.     

The First Ant-Termite Syninclusion in Amber with CT-Scan Analysis of Taphonomy

We describe here a co-occurrence (i.e. a syninclusion) of ants and termites in a piece of Mexican amber (Totolapa deposit, Chiapas), whose importance is two-fold. First, this finding suggests at least a middle Miocene antiquity for the modern, though poorly documented, relationship between Azteca ants and Nasutitermes termites. Second, the presence of a Neivamyrmex army ant documents an in situ raiding behaviour of the same age and within the same community, confirmed by the fact that the army ant is holding one of the termite worker between its mandibles and by the presence of a termite with bitten abdomen. In addition, we present how CT-scan imaging can be an efficient tool to describe the topology of resin flows within amber pieces, and to point out the different states of preservation of the embedded insects. This can help achieving a better understanding of taphonomical processes, and tests ethological and ecological hypotheses in such complex syninclusions.     

Two types of excretory pores in the hydrozoan medusa Aequorea victoria (Murbach and Shearer, 1902)

Aequorea victoria medusae possess radial canal excretory poreswhich egest large particles from the gastrovascular system inaddition to marginal excretory papillae on the tentacle bulbswhich egest finer particles.     

Cytochrome c oxidase subunit 1 barcode data of fish of the Nayband National Park in the Persian Gulf and analysis using meta-data flag several cryptic species

We provide cytochrome c oxidase subunit 1 (COI) barcode sequences of fishes of the Nayband National Park, Persian Gulf, Iran. Industrial activities, ecological considerations and goals of The Fish Barcode of Life campaign make it crucial that fish species residing in the park be identified. To the best of our knowledge, this is the first report of barcoding data on fishes of the Persian Gulf. We examined 187 individuals representing 76 species, 56 genera and 32 families. The data flagged potentially cryptic species of Gerres filamentosus and Plectorhinchus schotaf. 16S rDNA data on these species are provided. Exclusion of these two potential cryptic species resulted in a mean COI intraspecific distance of 0.18%, and a mean inter- to intraspecific divergence ratio of 66.7. There was no overlap between maximum Kimura 2-parameter distances among conspecifics (1.66%) and minimum distance among congeneric species (6.19%). Barcodes shared among species were not observed. Neighbour-joining analysis showed that most species formed cohesive sequence units with little variation. Finally, the comparison of 16 selected species from this study with meta-data of conspecifics from Australia, India, China and South Africa revealed high interregion divergences and potential existence of six cryptic species. Pairwise interregional comparisons were more informative than global divergence assessments with regard to detection of cryptic variation. Our analysis exemplifies optimal use of the expanding barcode data now becoming available.     

Biosensors for the Detection of Environmental and Urban Pollutions

Release of harmful pollutants such as heavy metals, pesticides, and pharmaceuticals to the environment is a global concern. Rapid and reproducible detection of these pollutants is thus necessary. Biosensors are the sensitive and high specific tools for detection of environmental pollutants. Broad range various types of biosensors have been fabricated for this purpose. This review focuses on the feature and application of biosensors developed for environmental and urban pollutants detection. J. Cell. Biochem. 119: 207–212, 2018. © 2017 Wiley Periodicals, Inc.     

Coherent Timescales and Mechanical Structure of Multicellular Aggregates

Multicellular aggregates are an excellent model system to explore the role of tissue biomechanics in specifying multicellular reorganization during embryonic developments and malignant invasion. Tissue-like spheroids, when subjected to a compressive force, are known to exhibit liquid-like behaviors at long timescales (hours), largely because of cell rearrangements that serve to effectively dissipate the applied stress. At short timescales (seconds to minutes), before cell rearrangement, the mechanical behavior is strikingly different. The current work uses shape relaxation to investigate the structural characteristics of aggregates and discovers two coherent timescales: one on the order of seconds, the other tens of seconds. These timescales are universal, conserved across a variety of tested species, and persist despite great differences in other properties such as tissue surface tension and adhesion. A precise mathematical theory is used to correlate the timescales with mechanical properties and reveals that aggregates have a relatively strong envelope and an unusually “soft” interior (weak bulk elastic modulus). This characteristic is peculiar, considering that both layers consist of identical units (cells), but is consistent with the fact that this structure can engender both structural integrity and the flexibility required for remodeling. In addition, tissue surface tension, elastic modulus, and viscosity are proportional to each other. Considering that these tissue-level properties intrinsically derive from cellular-level properties, the proportionalities imply precise coregulation of the latter and in particular of the tension on the cell-medium and cell-cell interfaces.     

Protein-protein cross-linking in the use of the eukaryotic eGST-fusion system

We describe here an unusual phenomenon in the isolation of protein complexes from eukaryotic cells using expressed GST-fusion proteins. Protein complexes are involved in a large number of regulatory mechanisms. Therefore, the use of tagged fusion proteins is an important tool for isolation of such protein complexes. For this purpose, we used the nuclear factor Alien, described as a corepressor for the thyroid hormone receptor, fused to the eukaryotic eGST and expressed this fusion in human cells. After affinity purification over glutathione-Sepharose using stringent washing steps, we observed several co-purifying bands migrating at molecular weights higher than the GST-Alien fusion protein. These bands appeared specifically in the GST-Alien transfected cell preparations. Surprisingly, using both Western blotting and MALDI-analyses, we revealed that these bands are composed of the GST-Alien protein itself. We hypothesize that overexpressed factors may generate unexpected cross-linking products which can confound the analyses of such affinity-purified complexes. The cross-linking products could not be eliminated by using beta-mercaptoethanol in the gel system and by boiling in SDS-sample buffer. Also, we demonstrate that Western blotting analyses using antibodies directed against both the tag-epitope and the expressed protein of interest can rapidly, reliably, and in a cost-saving manner identify such artifacts, eliminating them from the analyses of potentially interesting interaction partners. Our findings clearly show that the overexpression and purification of proteins from eukaryotic cells may generate unusual structural features that strongly influence complex formation and the migration in SDS-PAGE.     

Androgen receptor agonist and antagonist reduce response of cytokine-induced killer cells on prostate cancer cells

Despite many advances, prostate cancer (PCa) is still the second most frequently diagnosed cancer and fifth leading cause of cancer death in men worldwide. So far, the promising field of onco-immunology has not yet provided a satisfactory treatment option for PCa. Here we show that the ex vivo expansion and activation of cytokine-induced killer (CIK) cells isolated from primary peripheral blood mononuclear cells induce immune-mediated apoptosis in both human PCa LNCaP and C4-2 cells. Interestingly, pretreating LNCaP and C4-2 cells with either androgen or the androgen receptor (AR) antagonist enzalutamide mediates resistance to this immunogenic attack. This is associated with a reduction of both total cell loss and apoptosis levels suggesting one possible mechanism blunting onco-immunological activity. The data also suggest that secreted factors from AR ligand-treated PCa cell suppress lymphocyte proliferation. Further, we analysed immune-mediated killing activity using conditioned media from LNCaP and C4-2 treated cells. The obtained data suggest that the conditioned media from PCa treated cells does not influence a measurable lymphocyte-mediated apoptosis. However, analysing clonal expansion of activated lymphocytes, the androgen-derived conditioned media suppresses lymphocyte proliferation/expansion suggesting inhibition of onco-immunological activity by pretreatment of PCa cells with AR ligands.     

Distinct Roles for CdtA and CdtC during Intoxication by Cytolethal Distending Toxins

Cytolethal distending toxins (CDTs) are heterotrimeric protein exotoxins produced by a diverse array of Gram-negative pathogens. The enzymatic subunit, CdtB, possesses DNase and phosphatidylinositol 3-4-5 trisphosphate phosphatase activities that induce host cell cycle arrest, cellular distension and apoptosis. To exert cyclomodulatory and cytotoxic effects CDTs must be taken up from the host cell surface and transported intracellularly in a manner that ultimately results in localization of CdtB to the nucleus. However, the molecular details and mechanism by which CDTs bind to host cells and exploit existing uptake and transport pathways to gain access to the nucleus are poorly understood. Here, we report that CdtA and CdtC subunits of CDTs derived from Haemophilus ducreyi (Hd-CDT) and enteropathogenic E. coli (Ec-CDT) are independently sufficient to support intoxication by their respective CdtB subunits. CdtA supported CdtB-mediated killing of T-cells and epithelial cells that was nearly as efficient as that observed with holotoxin. In contrast, the efficiency by which CdtC supported intoxication was dependent on the source of the toxin as well as the target cell type. Further, CdtC was found to alter the subcellular trafficking of Ec-CDT as determined by sensitivity to EGA, an inhibitor of endosomal trafficking, colocalization with markers of early and late endosomes, and the kinetics of DNA damage response. Finally, host cellular cholesterol was found to influence sensitivity to intoxication mediated by Ec-CdtA, revealing a role for cholesterol or cholesterol-rich membrane domains in intoxication mediated by this subunit. In summary, data presented here support a model in which CdtA and CdtC each bind distinct receptors on host cell surfaces that direct alternate intracellular uptake and/or trafficking pathways.