Blue Hake Antimora rostrata (Gadiformes: Moridae) off the Atlantic Coast of South America: an Overview on Its Distribution and Biology

Journal of Ichthyology - Long-term data on spatial and bathymetric distributions, preferred bottom temperatures, length and weight of blue hake Antimora rostrata caught off the Atlantic coast of...     

Antitumor effect of miR-197 targeting in p53 wild-type lung cancer

Lung cancer is the leading cause of tumor-related death. The lack of effective treatments urges the development of new therapeutic approaches able to selectively kill cancer cells. The connection between aberrant microRNA (miRNA – miR) expression and tumor progression suggests a new strategy to fight cancer by interfering with miRNA function. In this regard, LNAs (locked nucleic acids) have proven to be very promising candidates for miRNA neutralization. Here, we employed an LNA-based anti-miR library in a functional screening to identify putative oncogenic miRNAs in non-small-cell lung cancer (NSCLC). By screening NIH-H460 and A549 cells, miR-197 was identified as a new functional oncomiR, whose downregulation induces p53-dependent lung cancer cell apoptosis and impairs the capacity to establish tumor xenografts in immunodeficient mice. We further identified the two BH3-only proteins NOXA and BMF as new miR-197 targets responsible for induction of apoptosis in p53 wild-type cells, delineating miR-197 as a key survival factor in NSCLC. Thus, we propose the inhibition of miR-197 as a novel therapeutic approach against lung cancer.     

4-Connected azabicyclo[5.3.0]decane Smac mimetics-Zn2+ chelators as dual action antitumoral agents

Putative dual action compounds (DACs 3a–d) based on azabicyclo[5.3.0]decane (ABD) Smac mimetic scaffolds linked to Zn²⁺-chelating 2,2′-dipicolylamine (DPA) through their 4 position are reported and characterized. Their synthesis, their target affinity (cIAP1 BIR3, Zn²⁺) in cell-free assays, their pro-apoptotic effects, and their cytotoxicity in tumor cells with varying sensitivity to Smac mimetics are described. A limited influence of Zn²⁺ chelation on in vitro activity of DPA-substituted DACs 3a–d was sometimes perceivable, but did not lead to strong cellular synergistic effects. In particular, the linker connecting DPA with the ABD scaffold seems to influence cellular Zn²⁺-chelation, with longer lipophilic linkers/DAC 3c being the optimal choice.     

Trophic ecology of the black drum,Pogonias cromis (Sciaenidae), in Mar Chiquita coastal lagoon (Argentina)

This is the first documentation on the feeding habits of the black drum, Pogonias cromis, in waters of South America. The aim of the investigation was to determine the trophic ecology of P. cromis in the Mar Chiquita coastal lagoon (37°32′–37°45′S; 57°19′–57°26′W) from stomach content analyses of 109 P. cromis specimens. Samples in various sizes were collected monthly using various types of fishing gear. The results showed that this species is a benthic predator focusing on bivalves and crabs. permanova results indicated significant seasonal differences in the diet. This pattern reflected seasonal changes in prey abundance and availability, which produced changes in both foraging strategy and trophic niche breadth. This indicates that P. cromis is a versatile predator, adapting its feeding strategy in response to a seasonal shift of prey abundance, and indicating an opportunist behavior.     

First record of a dicephalic specimen of tope Galeorhinus galeus (Elasmobranchii: Triakidae)

The first case of dicephalia in tope Galeorhinus galeus analysed in developing foetuses removed from a pregnant female caught off the Mar del Plata coastal waters, Argentine Sea, is reported here.     

Glyceraldehyde-3-phosphate dehydrogenase exerts different biologic activities in apoptotic and proliferating hepatocytes according to its subcellular localization

Recent evidences indicate new roles for the glycolytic protein glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in essential mammalian cell processes, such as apoptosis and proliferation. To clarify the involvement of this protein in growth and programmed cell death in the liver, cell models of hepatocytes in culture were used to study GAPDH expression, localization and enzymatic activity in hepatocyte proliferation and apoptosis. GAPDH expression in cell compartments was studied by Western blot. Nuclear expression of GAPDH increased in apoptosis, and cytoplasmic expression was elevated in apoptosis and proliferation. Subcellular localization was determined by GAPDH immunostaining and confocal microscopic analysis. Quiescent and proliferating hepatocytes showed cytoplasmic GAPDH, while apoptotic cells showed cytoplasmic but also some nuclear staining. The glycolytic activity of GAPDH was studied in nuclear and cytoplasmic cell compartments. GAPDH enzymatic activity increased in the nucleus of apoptotic cells and in cytoplasms of apoptotic and proliferating hepatocytes. Our observations indicate that during hepatocyte apoptosis GAPDH translocates to the nucleus, maintaining in part its dehydrogenase activity, and suggest that this translocation may play a role in programmed hepatocyte death. GAPDH over-expression and the increased enzymatic activity in proliferating cells, with preservation of its cytoplasmic localization, would occur in response to the elevated energy requirements of dividing hepatocytes. In conclusion, GAPDH plays different roles or biological activities in proliferating and apoptotic hepatocytes, according to its subcellular localization.     

Feeding habits of the Magellan skate: effects of sex, maturity stage, and body size on diet

The aim of this study was to evaluate the effects of sex, maturity stage, and body size on the diet of the Magellan skate, Bathyraja magellanica, in the Southwest Atlantic off Argentina, by examining stomach contents using a multiple hypothesis modeling approach. Relationships between the number of prey and sex, maturity stage, and total length (TL) were assessed by built generalized linear models (GLM). Furthermore, we tested whether there was a threshold size at which B. magellanica started or quit consuming a given prey. The overall diet of B. magellanica was mainly consisted of teleosts, followed by amphipods, isopods, and decapods. Ontogenetic diet shifts were independent of sex and maturity stage. However, discrete shifts in diet with TL were found, with individuals larger than 554 and 623 mm TL ceasing to consume amphipods and isopods, respectively. The consumption of teleosts progressively increased with increasing predator size. Likewise, ontogenetic shifts in foraging behavior were also observed with smaller individuals showing specialization on amphipods with larger specimens consuming teleosts. These results confirm that ontogenetic shifts in diet of B. magellanica are more a function of predator size rather than any other life-history traits. We propose that these food shifts are probably related to morphological limitations and abilities associated with feeding habits of skate, so when specimens of B. magellanica reach an optimum body size, they may have access to higher quality trophic resources. Our results suggest that evaluating the importance of life-history stages on the feeding habits of a species is essential for understanding how that species exploits food resources, which, in turn, is an important factor in developing a suitable plan of marine ecosystem conservation.     

Apoptotic and proliferating hepatocytes differ in prothymosin α expression and cell localization

Prothymosin α is an acidic protein, reported to be involved in cell proliferation and apoptosis, although its precise function in both processes are still unknown. Due to the importance of these processes in the pathogenesis of hepatic diseases and the need to understand the molecular mechanisms underlying these diseases we aimed to investigate the behavior of this protein in liver growth and apoptosis, in two models of hepatocytes in culture. Prothymosin α expression varied throughout the hepatocyte cell cycle, according to its progression. Proliferating hepatocytes showed increased expression of the protein, while apoptotic ones showed decreased levels. The subcellular location of prothymosin α differed according to the different phases of the cell cycle. Thus, it appeared with a stippled and widely dispersed pattern throughout the nucleus in quiescent and proliferating hepatocytes, while it became cytoplasmic in mitotic and late apoptotic cells. These results are in agreement with the idea that high levels of prothymosin α need to be present in the nucleus for proliferation, and programmed cell death requires low levels of prothymosin α outside of the nucleus. The differences in prothymosin α expression and localization during hepatocyte proliferation and apoptosis suggest that this protein may have a pleiotropic function that depends not only on its availability but also on its various localizations in different subcellular compartments.