Vitellogenin gene family in vertebrates: evolution and functions

The vitellogenin gene family is constituted of variable gene numbers encoding for polypeptides that are precursors of yolk proteins and derivatives in oviparous and ovoviviparous vertebrates. The comprehension of which mechanisms have shaped the evolution of vtg gene family represents an attractive field of research. The primary intent of this review is to summarize the evolutionary hypotheses that have been proposed over recent decades, highlighting the differences between the proposed models. Overall in vertebrates the evolutionary history of this gene family is the result of complex modifications deeply influenced by events such as Whole Genome Duplications (WGDs), lineage-specific gene losses and duplications. Interestingly the last hypothesis allowed to date the vitellogenin gene cluster origin in the common ancestor of gnathostomes. In addition, in the last decades, several works evidenced non-nutritional functions such as antibacterial, immunological and antioxidant activities overcoming its classical view as a simple source of nourishment for the developing embryos

Transposable elements in vertebrates: species evolution and environmental adaptation

The evolutionary success of species is strictly related to their genome in terms of composition and functionality. Transposable elements (TEs) represent a considerable fraction of the nuclear DNA content, and given to their ability to spread throughout the genome, they are able to create genetic diversity at sequence, gene structure, and chromosome level. Vertebrates represent a highly successful taxon and its lineages are characterized by a variable TE content suggesting a different impact on the genome. In this manuscript, we highlight the importance of TEs in creating new regulatory sequences and genetic innovations extremely useful for diversification of vertebrates. Moreover, an increasing number of evidence suggests a link between TEs and environment. Indeed, given the richness of species adapted to a wide range of habitats and conditions, vertebrates are exposed to several ecological pressures with consequent effects on evolutionary adaptation

Shedding light upon the complex net of genome size, genome composition and environment in chordates

The nucleotype theory has been advanced on the basis of studies regarding genome size and composition in various plant and animal species, i.e. the influence that genome can have on the phenotype independently of the informational content of DNA. It has also been noted that during evolution various interactions between different environmental factors and genome structural and functional parameters would have occurred. In this review, changes in genome size, transposon content, and base composition occurred during the evolution of chordates were examined. Many environmental stresses, such as temperature, can act on transposons and through these on genome size. Temperature is also one of the most important elements of natural selection able to interact both with base composition and genome size. It has been evidenced that temperature exerts a direct influence on base composition and its increase would have led to an higher content of genome GC-rich components during the evolution of chordates, in particular in endotherms. Temperature would have controlled the rate of biosynthesis in G1 phase and consequently the cell cycle duration which in turn would have interacted with genome size. The combined action of temperature, base composition, and genome size would also have been very important in controlling the metabolic rate. Finally, another important aspect of the nucleotypic effect is the influence that genome size and cell cycle duration, in correlation with environmental temperature, would have exert on embryo and larval development, very important for environmental adaptation. In conclusion, studies here reviewed to confirm the existence in chordates of a mutual influence between environment and genome non-coding components that would have played an important role in the evolution of these animals especially in environmental adaptation processes

CEIBO: un sistema informático para el diseño, basado en riesgo, de procesos industriales

Sociedad Argentina de Informática e Investigación Operativ

CEIBO: un sistema informático para el diseño, basado en riesgo, de procesos industriales

Sociedad Argentina de Informática e Investigación Operativ

CEIBO: un sistema informático para el diseño, basado en riesgo, de procesos industriales

Sociedad Argentina de Informática e Investigación Operativ

Androgen receptor expression in early triple-negative breast cancer: clinical significance and prognostic associations.

Background: Triple-negative breast cancers (TNBC) are characterized by aggressive tumour biology resulting in a poor prognosis. Androgen receptor (AR) is one of newly emerging biomarker in TNBC. In recent years, ARs have been demonstrated to play an important role in the genesis and in the development of breast cancer, although their prognostic role is still debated. In the present study, we explored the correlation of AR expression with clinical, pathological and molecular features and its impact on prognosis in early TNBC. Patients and Methods: ARs were considered positive in case of tumors with >10% nuclear-stained. Survival distribution was estimated by the Kaplan Meier method. The univariate and multivariate analyses were performed. The difference among variables were calculated by chi-square test. Results: 81 TNBC patients diagnosed between January 2006 and December 2011 were included in the analysis. Slides were stained immunohistochemically for estrogen and progesterone receptors, HER-2, Ki-67, ALDH1, e-cadherin and AR. Of the 81 TNBC samples, 18.8% showed positive immunostaining for AR, 23.5% and 44.4% of patients were negative for e-cadherin and ALDH1, respectively. Positive AR immunostaining was inversely correlated with a higher Ki-67 (p < 0.0001) and a lympho-vascular invasion (p = 0.01), but no other variables. Univariate survival analysis revealed that AR expression was not associated with disease-free survival (p = 0.72) or overall survival (p = 0.93). Conclusions: The expression of AR is associated with some biological features of TNBC, such as Ki-67 and lympho-vascular invasion; nevertheless the prognostic significance of AR was not documented in our analysis. However, since ARs are expressed in a significant number of TNBC, prospective studies in order to determine the biological mechanisms and their potential role as novel treatment target

Effects of Dietary Fibers on Short-Chain Fatty Acids and Gut Microbiota Composition in Healthy Adults: A Systematic Review

There is an increasing interest in investigating dietary strategies able to modulate the gut microbial ecosystem which, in turn, may play a key role in human health. Dietary fibers (DFs) are widely recognized as molecules with prebiotic effects. The main objective of this systematic review was to: (i) analyze the results available on the impact of DF intervention on short chain fatty acids (SCFAs) production; (ii) evaluate the interplay between the type of DF intervention, the gut microbiota composition and its metabolic activities, and any other health associated outcome evaluated in the host. To this aim, initially, a comprehensive database of literature on human intervention studies assessing the effect of confirmed and candidate prebiotics on the microbial ecosystem was developed. Subsequently, studies performed on DFs and analyzing at least the impact on SCFA levels were extracted from the database. A total of 44 studies from 42 manuscripts were selected for the analysis. Among the different types of fiber, inulin was the DF investigated the most (n = 11). Regarding the results obtained on the ability of fiber to modulate total SCFAs, seven studies reported a significant increase, while no significant changes were reported in five studies, depending on the analytical methodology used. A total of 26 studies did not show significant differences in individual SCFAs, while the others reported significant differences for one or more SCFAs. The effect of DF interventions on the SCFA profile seemed to be strictly dependent on the dose and the type and structure of DFs. Overall, these results underline that, although affecting microbiota composition and derived metabolites, DFs do not produce univocal significant increase in SCFA levels in apparently healthy adults. In this regard, several factors (i.e., related to the study protocols and analytical methods) have been identified that could have affected the results obtained in the studies evaluated. Future studies are needed to better elucidate the relationship between DFs and gut microbiota in terms of SCFA production and impact on health-related markers