Single and combined effects of two trace elements (Cd and Cu) on the asexual reproduction of Aurelia sp. polyps

Aquatic Ecology - Jellyfish blooms are an increasingly common event in our seas. Occurring via polyps’ asexual reproduction induced by human stresses, they represent a hazard for ecosystems...     

Leapfrog migration and residents: New migratory habits in Swedish Greylag geese

Knowledge about intraspecific and individual variation in bird migration behavior is important to predict spatiotemporal distribution, patterns of phenology, breeding success, and interactions with the surrounding environment (e.g., human livelihoods). Such variation is key to adaptive, evolutionary responses, i.e., how individuals respond spatiotemporally to the environment to maximize fitness. In this study we used GPS location data from one to three full annual cycles from 76 Greylag geese (Anser anser) to test the hypothesis that geese originating at five latitudinally separated capture sites in Sweden have different migration strategies. We also assessed individual consistency in movement strategy over consecutive annual cycles. We used the scale‐independent net squared displacement modeling framework to quantify variables of autumn and spring migration for geese from each capture site: distance, timing, and duration. Our results demonstrate a positive correlation between migration distance and latitudinal origin. Geese from the northernmost site on average migrated farther south and about 15 times as far as the short‐moving or resident geese from the two southernmost sites. Movement strategies of individual geese varied considerably both within and among capture sites. Individual consistency in movement strategy from one annual cycle to the consecutive was high in geese from the northern sites moving the farthest, whereas the resident or short‐moving geese from the southernmost sites generally showed lower or no individual consistency. These changes have come about during a time span so short (i.e., ca. 35 years or 8–10 generations) that it can unlikely be explained by classical Darwinian between‐generation adaptation. Consequently, and given that young geese follow their parents during their first migration, we presume an important role of within‐family, inter‐generation change as a driver behind the large‐scale changed migration habits in Swedish Greylag geese.     

Lamin A and the LINC complex act as potential tumor suppressors in Ewing Sarcoma

Lamin A, a main constituent of the nuclear lamina, is involved in mechanosignaling and cell migration through dynamic interactions with the LINC complex, formed by the nuclear envelope proteins SUN1, SUN2 and the nesprins. Here, we investigated lamin A role in Ewing Sarcoma (EWS), an aggressive bone tumor affecting children and young adults. In patients affected by EWS, we found a significant inverse correlation between LMNA gene expression and tumor aggressiveness. Accordingly, in experimental in vitro models, low lamin A expression correlated with enhanced cell migration and invasiveness and, in vivo, with an increased metastatic load. At the molecular level, this condition was linked to altered expression and anchorage of nuclear envelope proteins and increased nuclear retention of YAP/TAZ, a mechanosignaling effector. Conversely, overexpression of lamin A rescued LINC complex organization, thus reducing YAP/TAZ nuclear recruitment and preventing cell invasiveness. These effects were also obtained through modulation of lamin A maturation by a statin-based pharmacological treatment that further elicited a more differentiated phenotype in EWS cells. These results demonstrate that drugs inducing nuclear envelope remodeling could be exploited to improve therapeutic strategies for EWS.Subject terms: Nuclear organization, Cancer     

TNFalpha induces NFkappaB/p50 in association with the growth and morphogenesis of normal and transformed rat mammary epithelial cells

In contrast to the cytotoxic or cytostatic effect of TNFalpha on many breast cancer cell lines, TNFalpha stimulates growth and morphogenesis of normal rat mammary epithelial cells (MEC). The present studies were carried out to determine whether there are intrinsic differences between normal and malignant MEC which may explain the differing responsiveness to TNFalpha. Freshly isolated rat MEC organoids from normal mammary gland or 1-methyl-1-nitrosourea-induced mammary tumors were treated with TNFalpha for 21 days. Unexpectedly, TNFalpha stimulated growth and morphogenesis of both normal and transformed MEC in primary culture, although in transformed cells its effects were delayed and the majority of the colonies were histologically abnormal, with multiple cell layers and no lumen. Since NFkappaB is a key mediator of TNFalpha action and has been implicated in carcinogenesis, the expression of the p50, p52, p65, and c-rel NFkappaB proteins in normal and transformed MEC was determined. Expression of p52 was significantly reduced in tumor cells, and p50 was absent, although its putative precursor, p105 was abundant. There were no changes in the levels of p65 or c-rel. TNFalpha induced a pronounced and sustained increase of a p50 homodimeric NFkappaB/DNA complex in both normal and transformed MEC. However, in transformed MEC, NFkappaB binding was initially undetectable but then increased in response to TNFalpha. Thus, NFkappaB expression and DNA binding activity are altered during mammary carcinogenesis. In addition, the significant increase in NFkappaB/p50 DNA-binding was temporally coincident with TNFalpha-induced growth and morphogenesis, suggesting that it may play a significant role in both normal development and carcinogenesis.     

Salicylic acid-independent plant defence pathways

Salicylic acid is an important signalling molecule involved in both locally and systemically induced disease resistance responses. Recent advances in our understanding of plant defence signalling have revealed that plants employ a network of signal transduction pathways, some of which are independent of salicylic acid. Evidence is emerging that jasmonic acid and ethylene play key roles in these salicylic acid-independent pathways. Cross-talk between the salicylic acid-dependent and the salicylic acid-independent pathways provides great regulatory potential for activating multiple resistance mechanisms in varying combinations.     

Fine structure of the gill epithelium of the terrestrial mudskipper, Periophthalmodon schlosseri

In this paper, we describe the fine structure of the branchial epithelium of the amphibious, air-breathing mudskipper Periophthalmodon schlosseri, and relate the observed structure to functions in gas exchange, and to the elimination of sodium chloride and ammonia. Also, we describe the fine structure of the opercular epithelimicrom. The gill lamellar epithelium is thickened by the presence of large mitochondria-rich (MR) cells. These MR cells are further characterized by an extensive tubular system that is continuous with the basolateral plasma membrane and by a deep apical crypt often lined with microvilli. There are very few specialized MR accessory cells, which are associated with NaCl excretion in marine teleosts. Instead, MR cells are commonly isolated from each other laterally by flattened cells rich in intermediate filaments. These filament-rich (FR) cells are interconnected by desmosomes and have unusual canaliculi. These branchial FR cells are unique to P. schlosseri and may have a structural role. Electron-dense pavement cells rich in vesicles and large vacuous mitochondria compose the superficial layer of the epithelium. The unusual morphology of P. schlosseri's gill lamellae may be related to the animal's ability to effectively eliminate ammonia during air exposure. The inner opercular lining and parts of the leading edge of the filament have intraepithelial capillaries, which provide a more suitable gas exchange surface than the thickened lamellae with its restricted interlamellar water spaces. The arrangement of respiratory and ion exchange epithelia is opposite to that found in all other fish in which the lamellae typically function in gas exchange and the gill filament in ion regulation.     

Covalent binding of the 13C-labeled skin sensitizers 5-chloro-2-methylisothiazol-3-one (MCI) and 2-methylisothiazol-3-one (MI) to a model peptide and glutathione

The reactivity of 4-[13C]- and 5-[13C]-5-chloro-2-methylisothiazol-3-one (MCI) and 2-methylisothiazol-3-one (MI) towards a model peptide and glutathione was followed by 13C and 1H[13C] NMR spectroscopy. Both molecules were found to react with GSH but in addition MCI was found to react with histidine and lysine to form adducts of a different nature. Reaction with histidine led to stable substitution adducts through an addition-elimination reaction at position 5 while reaction with lysine led to the formation of open adducts of the thioamide or amide type.     

Learning the codes of fly immunity

Insect antimicrobial response serves as an excellent model for studying human innate immunity. In this issue of Molecular Cell, Senger and colleagues demonstrate that a large number of immunity genes in Drosophila fat bodies can be regulated by a simple code, REL-GATA.