The Pattern of Change in the Abundances of Specific Bacterioplankton Groups Is Consistent across Different Nutrient-Enriched Habitats in Crete

A common source of disturbance for coastal aquatic habitats is nutrient enrichment through anthropogenic activities. Although the water column bacterioplankton communities in these environments have been characterized in some cases, changes in α-diversity and/or the abundances of specific taxonomic groups across enriched habitats remain unclear. Here, we investigated the bacterial community changes at three different nutrient-enriched and adjacent undisturbed habitats along the north coast of Crete, Greece: a fish farm, a closed bay within a town with low water renewal rates, and a city port where the level of nutrient enrichment and the trophic status of the habitat were different. Even though changes in α-diversity were different at each site, we observed across the sites a common change pattern accounting for most of the community variation for five of the most abundant bacterial groups: a decrease in the abundance of the Pelagibacteraceae and SAR86 and an increase in the abundance of the Alteromonadaceae, Rhodobacteraceae, and Cryomorphaceae in the impacted sites. The abundances of the groups that increased and decreased in the impacted sites were significantly correlated (positively and negatively, respectively) with the total heterotrophic bacterial counts and the concentrations of dissolved organic carbon and/or dissolved nitrogen and chlorophyll α, indicating that the common change pattern was associated with nutrient enrichment. Our results provide an in situ indication concerning the association of specific bacterioplankton groups with nutrient enrichment. These groups could potentially be used as indicators for nutrient enrichment if the pattern is confirmed over a broader spatial and temporal scale by future studies.     

An N-terminal pro-atrial natriuretic peptide (NT-proANP) ‘aggregation-prone’ segment involved in isolated atrial amyloidosis

Isolated atrial amyloidosis (IAA) is a common localized form of amyloid deposition within the atria of the aging heart. The main constituents of amyloid fibrils are atrial natriuretic peptide (ANP) and the N-terminal part of its precursor form (NT-proANP). An ‘aggregation-prone’ heptapeptide (¹¹⁴KLRALLT¹²⁰) was located within the NT-proANP sequence. This peptide self-assembles into amyloid-like fibrils in vitro, as electron microscopy, X-ray fiber diffraction, ATR FT-IR spectroscopy and Congo red staining studies reveal. Consequently, remedies/drugs designed to inhibit the aggregation tendency of this ‘aggregation-prone’ segment of NT-proANP may assist in prevention/treatment of IAA, congestive heart failure (CHF) or atrial fibrillation (AF).     

TGFβ and matrix-regulated epithelial to mesenchymal transition

Background

The progression of cancer through stages that guide a benign hyperplastic epithelial tissue towards a fully malignant and metastatic carcinoma, is driven by genetic and microenvironmental factors that remodel the tissue architecture. The concept of epithelial–mesenchymal transition (EMT) has evolved to emphasize the importance of plastic changes in tissue architecture, and the cross-communication of tumor cells with various cells in the stroma and with specific molecules in the extracellular matrix (ECM).

Scope of the review

Among the multitude of ECM-embedded cytokines and the regulatory potential of ECM molecules, this article focuses on the cytokine transforming growth factor β (TGFβ) and the glycosaminoglycan hyaluronan, and their roles in cancer biology and EMT. For brevity, we concentrate our effort on breast cancer.

Major conclusions

Both normal and abnormal TGFβ signaling can be detected in carcinoma and stromal cells, and TGFβ-induced EMT requires the expression of hyaluronan synthase 2 (HAS2). Correspondingly, hyaluronan is a major constituent of tumor ECM and aberrant levels of both hyaluronan and TGFβ are thought to promote a wounding reaction to the local tissue homeostasis. The link between EMT and metastasis also involves the mesenchymal–epithelial transition (MET). ECM components, signaling networks, regulatory non-coding RNAs and epigenetic mechanisms form the network of regulation during EMT-MET.

General significance

Understanding the mechanism that controls epithelial plasticity in the mammary gland promises the development of valuable biomarkers for the prognosis of breast cancer progression and even provides new ideas for a more integrative therapeutic approach against disease. This article is part of a Special Issue entitled Matrix-mediated cell behaviour and properties.     

The Role of Estrogen Receptor β in Prostate Cancer

Although androgen receptor (AR) signaling is the main molecular tool regulating growth and function of the prostate gland, estrogen receptor β (ERβ) is involved in the differentiation of prostatic epithelial cells and numerous antiproliferative actions on prostate cancer cells. However, ERβ splice variants have been associated with prostate cancer initiation and progression mechanisms. ERβ is promising as an anticancer therapy and in the prevention of prostate cancer. Herein, we review the recent experimental findings of ERβ signaling in the prostate.     

An Extended Active-site Motif Controls the Reactivity of the Thioredoxin Fold

Proteins belonging to the thioredoxin (Trx) superfamily are abundant in all organisms. They share the same structural features, arranged in a seemingly simple fold, but they perform a multitude of functions in oxidative protein folding and electron transfer pathways. We use the C-terminal domain of the unique transmembrane reductant conductor DsbD as a model for an in-depth analysis of the factors controlling the reactivity of the Trx fold. We employ NMR spectroscopy, x-ray crystallography, mutagenesis, in vivo functional experiments applied to DsbD, and a comparative sequence analysis of Trx-fold proteins to determine the effect of residues in the vicinity of the active site on the ionization of the key nucleophilic cysteine of the -CXXC- motif. We show that the function and reactivity of Trx-fold proteins depend critically on the electrostatic features imposed by an extended active-site motif.     

Analysis of a zebrafish behavioral mutant reveals a dominant mutation in atp2a1/SERCA1

Zebrafish embryos demonstrate robust swimming behavior, which consists of smooth, alternating body bends. In contrast, several motility mutants have been identified that perform sustained, bilateral trunk muscle contractions which result in abnormal body shortening. Unlike most of these mutants, accordion (acc)^dta5 demonstrates a semidominant effect: Heterozygotes exhibit a distinct but less severe phenotype than homozygotes. Using molecular‐genetic mapping and candidate gene analysis, we determined that acc^dta5 mutants harbor a novel mutation in atp2a1, which encodes SERCA1, a calcium pump important for muscle relaxation. Previous studies have shown that eight other acc alleles compromise SERCA1 function, but these alleles were all reported to be recessive. Quantitative behavioral assays, complementation testing, and analysis of molecular models all indicate that the acc^dta5 mutation diminishes SERCA1 function to a greater degree than other acc alleles through either haploinsufficient or dominant‐negative molecular mechanisms. Since mutation of human ATP2A1 results in Brody disease, an exercise‐induced impairment of muscle relaxation, acc^dta5 mutants may provide a particularly sensitive model of this disorder. genesis, 48:354–361, 2010. © 2010 Wiley‐Liss, Inc.     

Acteoside and martynoside exhibit estrogenic/antiestrogenic properties

Acteoside and martynoside are plant phenylpropanoid glycosides exhibiting anticancer, cytotoxic and antimetastatic activities. We investigated their potential to activate estrogen receptor isoforms ERalpha and ERbeta in HeLa cells transfected with an estrogen response element (ERE)-driven luciferase (Luc) reporter gene and an ERalpha or ERbeta expression vector. Their estrogenic/antiestrogenic effects were also assessed in breast cancer cells (MCF7), endometrial cancer cells (Ishikawa) and osteoblasts (KS483), by measuring IGFBP3 levels, cell viability and number of mineralized nodules, respectively, seeking for a natural selective estrogen receptor modulator (SERM). Acteoside and martynoside antagonized both ERalpha and ERbeta (p<0.001), whereas they reversed the effect of E(2) mainly via ERalpha (p<0.001). Martynoside was a potent antiestrogen in MCF-7 cells, increasing, like ICI182780, IGFBP3 levels via the ER-pathway. In osteoblasts, martynoside induced nodule mineralization, which was abolished by ICI182780, implicating an ER-mediated mechanism. Furthermore, its antiproliferative effect on endometrial cells suggests that martynoside may be an important natural SERM. Acteoside was an antiestrogen in breast cancer cells and osteoblasts, without any effect on endometrial cells. Our study suggests that the nature is rich in selective ERalpha and ERbeta ligands, the discovery of which may lead to the development of novel neutraceutical agents.     

Deep-Sea Biodiversity in the Mediterranean Sea: The Known,the Unknown,and the Unknowable

Deep-sea ecosystems represent the largest biome of the global biosphere, but knowledge of their biodiversity is still scant. The Mediterranean basin has been proposed as a hot spot of terrestrial and coastal marine biodiversity but has been supposed to be impoverished of deep-sea species richness. We summarized all available information on benthic biodiversity (Prokaryotes, Foraminifera, Meiofauna, Macrofauna, and Megafauna) in different deep-sea ecosystems of the Mediterranean Sea (200 to more than 4,000 m depth), including open slopes, deep basins, canyons, cold seeps, seamounts, deep-water corals and deep-hypersaline anoxic basins and analyzed overall longitudinal and bathymetric patterns. We show that in contrast to what was expected from the sharp decrease in organic carbon fluxes and reduced faunal abundance, the deep-sea biodiversity of both the eastern and the western basins of the Mediterranean Sea is similarly high. All of the biodiversity components, except Bacteria and Archaea, displayed a decreasing pattern with increasing water depth, but to a different extent for each component. Unlike patterns observed for faunal abundance, highest negative values of the slopes of the biodiversity patterns were observed for Meiofauna, followed by Macrofauna and Megafauna. Comparison of the biodiversity associated with open slopes, deep basins, canyons, and deep-water corals showed that the deep basins were the least diverse. Rarefaction curves allowed us to estimate the expected number of species for each benthic component in different bathymetric ranges. A large fraction of exclusive species was associated with each specific habitat or ecosystem. Thus, each deep-sea ecosystem contributes significantly to overall biodiversity. From theoretical extrapolations we estimate that the overall deep-sea Mediterranean biodiversity (excluding prokaryotes) reaches approximately 2805 species of which about 66% is still undiscovered. Among the biotic components investigated (Prokaryotes excluded), most of the unknown species are within the phylum Nematoda, followed by Foraminifera, but an important fraction of macrofaunal and megafaunal species also remains unknown. Data reported here provide new insights into the patterns of biodiversity in the deep-sea Mediterranean and new clues for future investigations aimed at identifying the factors controlling and threatening deep-sea biodiversity.