Influence of <Emphasis Type="Italic">Moraxella</Emphasis> sp. colonization on the kidney proteome of farmed gilthead sea breams (<Emphasis Type="Italic">Sparus aurata</Emphasis>, L.)

Background  

Currently, presence of Moraxella sp. in internal organs of fish is not considered detrimental for fish farming. However, bacterial colonization of internal organs can affect fish wellness and decrease growth rate, stress resistance, and immune response. Recently, there have been reports by farmers concerning slow growth, poor feed conversion, and low average weight increase of fish farmed in offshore floating sea cages, often associated with internal organ colonization by Moraxella sp. Therefore, presence of these opportunistic bacteria deserves further investigations for elucidating incidence and impact on fish metabolism.     

Derivation and characterization of pluripotent cell lines from pig embryos of different origins

Embryonic stem cells (ESCs) hold great promise for therapeutic use and represent a unique tool for investigating the process of self-renewal and differentiation. The properties that make ESCs unique are their capacity of unlimited self-renewal coupled with the property of re-entering the developmental process if returned inside a blastocyst. Such plasticity enable ESCs to form all embryonic tissues including germ cells. However, these remarkable properties, at present, have been demonstrated only for mouse ESCs even if cells with somehow more limited capacities have been derived in many different species including humans. The isolation of pluripotent embryonic cells lines from human embryos marked a crucial change of perspective in evaluating the properties defining an embryonic stem cell lines moving the focus from the generation of a germ-line chimera, obviously not feasible nor desirable in human, to the capacity of these cells to differentiate both in vivo and in vitro in fully mature and functional cell types of all kinds. Therefore, ESCs properties in species different from the mouse are being reassessed and re-evaluated, in view of their potential use as experimental models for the development of clinical applications. Among the species that may play a useful role in this field, the pig has a long-standing history as a prime animal model for pre-clinical biomedical applications and therefore, pig ESCs are attracting renewed interest. In this review, we will summarize the current knowledge on this topic and will contrast the relatively limited data available in this species with the much larger wealth of information available for mouse and human ESCs, in an attempt to assess whether or not pig ESCs can actually become a useful tool in the fast growing field of cell therapy.     

Allometric scaling of lung volume and its consequences for marine turtle diving performance

Marine turtle lungs have multiple functions including respiration, oxygen storage and buoyancy regulation, so lung size is an important indicator of dive performance. We determined maximum lung volumes (V(L)) for 30 individuals from three species (Caretta caretta n=13; Eretmochelys imbricata n=12; Natator depressus n=5) across a range of body masses (M(b)): 0.9 to 46 kg. V(L) was 114 ml kg(-1) and increased with M(b) with a scaling factor of 0.92. Based on these values for V(L) we demonstrated that diving capacities (assessed via aerobic dive limits) of marine turtles were potentially over-estimated when the V(L)-body mass effect was not considered (by 10 to 20% for 5 to 25 kg turtles and by >20% for turtles > or =25 kg). While aerobic dive limits scale with an exponent of 0.6, an analysis of average dive durations in free-ranging chelonian marine turtles revealed that dive duration increases with a mass exponent of 0.51, although there was considerable scatter around the regression line. While this highlights the need to determine more parameters that affect the duration-body mass relationship, our results provide a reference point for calculating oxygen storage capacities and air volumes available for buoyancy control.     

Expression of a Catalytically Inactive Mutant Form of Glutathione Peroxidase 4 (Gpx4) Confers a Dominant-negative Effect in Male Fertility

The selenoenzyme Gpx4 is essential for early embryogenesis and cell viability for its unique function to prevent phospholipid oxidation. Recently, the cytosolic form of Gpx4 was identified as an upstream regulator of a novel form of non-apoptotic cell death, called ferroptosis, whereas the mitochondrial isoform of Gpx4 was previously shown to be crucial for male fertility. Here, we generated and analyzed mice with a targeted mutation of the active site selenocysteine of Gpx4 (Gpx4_U46S). Mice homozygous for Gpx4_U46S died at the same embryonic stage (E7.5) as Gpx4^−/− embryos as expected. Surprisingly, male mice heterozygous for Gpx4_U46S presented subfertility. Subfertility was manifested in a reduced number of litters from heterozygous breeding and an impairment of spermatozoa to fertilize oocytes in vitro. Morphologically, sperm isolated from heterozygous Gpx4_U46S mice revealed many structural abnormalities particularly in the spermatozoa midpiece due to improper oxidation and polymerization of sperm capsular proteins and malformation of the mitochondrial capsule surrounding and stabilizing sperm mitochondria. These findings are reminiscent of sperm isolated from selenium-deprived rodents or from mice specifically lacking mitochondrial Gpx4. Due to a strongly facilitated incorporation of Ser in the polypeptide chain as compared with selenocysteine at the UGA codon, expression of the catalytically inactive Gpx4_U46S was found to be strongly increased. Because the stability of the mitochondrial capsule of mature spermatozoa depends on the moonlighting function of Gpx4 both as an enzyme oxidizing capsular protein thiols and as a structural protein, tightly controlled expression of functional Gpx4 emerges as a key for full male fertility.     

Pidotimod: the state of art

Despite the use of antibiotics and vaccines, the frequency of respiratory tract infections is still high and these infections interest a wide range of patients, from children to aged people, including in particular these extreme categories because of the deficiency of their immune system, due to immaturity in the former case and to “immunosenescence” in the latter. For that reason immunostimulant drugs are getting more important to prevent and to attenuate infections. Pidotimod (3-L-pyroglutamyl-L-thiazolidine-4carboxylic acid) is a synthetic dipeptide with immunomodulatory properties. We reviewed studies conducted on different categories of patients, with particular attention on children and senile patients suffering from recurrent respiratory tract infections, associated, or not, with asthma or COPD. The outcomes considered are both clinical and laboratory parameters. The common end-point of these studies is that Pidotimod has an immunomodulatory activity which is able both to improve the clinical conditions of patients and to enhance and stimulate their immunity cells (lymphocytes but not only) functions acting on adaptive and innate immunity. Pidotimod is also able to increase the concentration of salivary IgA directed against bacteria; furthermore, it can modulate airway epithelial cells functions up-regulating the expression of toll-like receptors and acting on adhesion molecules. According to studies conducted on patients with atopic asthma, it seems that Pidotimod could affect T-lymphocytes balance with a possible addictional anti-allergic activity. Furthermore, it has been demonstrated an improvement of FEV1 and PEF in asthmatic patients treated with Pidotimod. Main clinical outcomes are the reduction of the number of infectious episodes, lesser severity of signs and symptoms and, consequently, a reduction in use of antibiotics and symptomatic drugs, less working and school days lost, less mortality and morbidity. The studies considered give positive results, confirming Pidotimod’s efficacy. Furthermore, many studies show a good safety profile of the drug, without recording serious adverse events and mutagenic potential, and a very low incidence of side effects. Pidotimod is also a more safe solution in patients subjected to vaccination, if compared to lyophilized polibacterial, which can’t be administered for thirty days before vaccination.     

Estimated comparative integration hotspots identify different behaviors of retroviral gene transfer vectors

Integration of retroviral vectors in the human genome follows non random patterns that favor insertional deregulation of gene expression and may cause risks of insertional mutagenesis when used in clinical gene therapy. Understanding how viral vectors integrate into the human genome is a key issue in predicting these risks. We provide a new statistical method to compare retroviral integration patterns. We identified the positions where vectors derived from the Human Immunodeficiency Virus (HIV) and the Moloney Murine Leukemia Virus (MLV) show different integration behaviors in human hematopoietic progenitor cells. Non-parametric density estimation was used to identify candidate comparative hotspots, which were then tested and ranked. We found 100 significative comparative hotspots, distributed throughout the chromosomes. HIV hotspots were wider and contained more genes than MLV ones. A Gene Ontology analysis of HIV targets showed enrichment of genes involved in antigen processing and presentation, reflecting the high HIV integration frequency observed at the MHC locus on chromosome 6. Four histone modifications/variants had a different mean density in comparative hotspots (H2AZ, H3K4me1, H3K4me3, H3K9me1), while gene expression within the comparative hotspots did not differ from background. These findings suggest the existence of epigenetic or nuclear three-dimensional topology contexts guiding retroviral integration to specific chromosome areas.     

A proteomic approach to study parathyroid glands

Parathyroid tumours are heterogeneous and in some cases the diagnosis may be difficult using histological features. In this study we used a two-dimensional electrophoresis (2D)/mass spectrometry (MS)-based approach to examine the global changes of parathyroid adenoma tissues protein profile compared to the parathyroid normal tissues. Validation of protein expression was performed by immunoblotting using specific antibodies. Ingenuity software was used to identify the biological processes to which these proteins belong and to construct a potential network. A total of 30 proteins were found to be differentially expressed, of which 22 resulted in being over-expressed. Proteins identified by 2D/MS/MS proteomics were classified into functional categories and a major change (≥ 2-fold) in terms of expression was found in proteins involved in response to biotic stimuli, cell organization and signal transduction. After Ingenuity analysis, 14-3-3 ζ/δ appears to be a key protein in the network of parathyroid adenoma, where it is linked to other proteins such as annexin A2, B box and SPRY domain-containing protein (BSPRY), p53 and epidermal growth factor receptor (EGFR). Our results suggest that the proteomic approach was able to differentiate the protein profiles of normal parathyroid and parathyroid adenoma and identify a panel of proteins which are differentially expressed. The functional role of these proteins in the network of intracellular pathways is discussed.     

The actin cytoskeleton is required for selective types of autophagy, but not nonspecific autophagy, in the yeast Saccharomyces cerevisiae

Autophagy is a catabolic multitask transport route that takes place in all eukaryotic cells. During starvation, cytoplasmic components are randomly sequestered into huge double-membrane vesicles called autophagosomes and delivered into the lysosome/vacuole where they are destroyed. Cells are able to modulate autophagy in response to their needs, and under certain circumstances, cargoes such as aberrant protein aggregates, organelles and bacteria can be selectively and exclusively incorporated into autophagosomes. In the yeast Saccharomyces cerevisiae, for example, double-membrane vesicles are used to transport the Ape1 protease into the vacuole, or for the elimination of superfluous peroxisomes. In the present study we reveal that in this organism, actin plays a role in these two types of selective autophagy but not in the nonselective, bulk process. In particular, we show that precursor Ape1 is not correctly recruited to the PAS, the putative site of double-membrane vesicle biogenesis, and superfluous peroxisomes are not degraded in a conditional actin mutant. These phenomena correlate with a defect in Atg9 trafficking from the mitochondria to the PAS.