The serine protease HtrA1 is upregulated in the human placenta during pregnancy.

The placenta has a dynamic and continuous capacity for self-renewal. The molecular mechanisms responsible for controlling trophoblast proliferation are still unclear. It is generally accepted that the simultaneous activity of proteins involved in cell proliferation, apoptosis, and extracellular matrix degradation plays an important role in correct placental development. We investigated in depth the expression of the serine protease HtrA1 during pregnancy in human placenta by in situ hybridization and immunohistochemistry, we demonstrated that HtrA1 displayed a low level of expression in the first trimester of gestation and a strong increase of HtrA1 expression in the third trimester. Finally, by electron microscopy, we demonstrated that HtrA1 was localized either in the cytoplasm of placental cells, especially close to microvilli that characterized the plasma membrane of syncytiotrophoblast cells, or in the extracytoplasmic space of the stroma of placental villi, particularly in the spaces between collagen fibers and on collagen fibers themselves. The expression pattern of HtrA1 in human placentas strongly suggests a role for this protein in placental development and function. Moreover, on the basis of its subcellular distribution it can be postulated that HtrA1 acts on different targets, such as intracellular growth factors or extracellular matrix proteins, to favor the correct formation/function of the placenta.     

High Diversity among Environmental Escherichia coli Isolates from a Bovine Feedlot

Approximately 280 Escherichia coli isolates were isolated from a bovine feedlot at the University of Connecticut campus via enrichment in lauryl tryptose broth and random selection from MacConkey plates. The E. coli subspecies diversity was estimated by employing whole-cell BOX-PCR genomic fingerprints. A total of 89 distinct operational taxonomic units (OTUs) were identified by employing a criterion of 85% fingerprint similarity as a surrogate for an OTU, while the Chao1 index estimated the E. coli population richness at 128 OTUs. One genotype (at a similarity level of 60%) dominated the population at 66% regardless of sampling depth or location, while no significant vertical distribution pattern was observed in terms of genotype, mobility, antibiotic resistance profile, or biofilm-forming ability. Motility, measured by a soft agar assay, had a very broad range among the E. coli population and was positively correlated with biofilm-forming ability in minimal medium (Spearman's rank correlation coefficient r = 0.619, P < 10⁻⁴) but not in Luria broth. Only an estimated 48% of the population possessed gene agn43, which encodes Ag43, a phase-variable outer membrane protein that has been implicated in biofilm formation in minimal medium. We observed significantly more biofilm formation in both minimal medium and Luria broth for agn43⁺ strains, with a larger effect in minimal medium. This study represents an exhaustive inventory of extant E. coli population diversity at a bovine feedlot and reveals significant subspecies heterogeneity in interfacial behavior.     

Taurine and Skeletal Muscle Disorders

Taurine is abundantly present in skeletal muscle. We give evidence that this amino acid exerts both short-term and long-term actions in the control of ion channel function and calcium homeostasis in striated fibers. Short-term actions can be estimated as the ability of this amino acid to acutely modulate both ion channel gating and the function of the structures involved in calcium handling. Long-term effects can be disclosed in situations of tissue taurine depletion and are likely related to the ability of the intracellular taurine to control transducing pathways as well as homeostatic and osmotic equilibrium in the tissue. The two activities are strictly linked because the intracellular level of taurine modulates the sensitivity of skeletal muscle to the exogenous application of taurine. Myopathies in which ion channels are directly or indirectly involved, as well as inherited or acquired pathologies characterized by metabolic alterations and change in calcium homeostasis, are often correlated with change in muscle taurine concentration and consequently with an enhanced therapeutic activity of this amino acid. We discuss both in vivo and in vitro evidence that taurine, through its ability to control sarcolemmal excitability and muscle contractility, can prove beneficial effects in many muscle dysfunctions.     

Role of glycosphingolipid SSEA‐3 and FGF2 in the stemness and lineage commitment of multilineage differentiating stress enduring (MUSE) cells

ObjectivesMultilineage differentiating Stress Enduring (MUSE) cells are endogenous, stress‐resistant stem cells, expressing pluripotency master genes and able to differentiate in cells of the three embryonic sheets. Stage‐Specific Embryonic Antigen 3 (SSEA‐3), a glycosphingolipid (GSL), is the marker for identifying MUSE cells and is used to isolate this population from mesenchymal stromal cells. GSLs modulate signal transduction by interacting with plasma membrane components. The growth factor FGF2, important for MUSE cells biology, may interact with GSLs. Specific cell surface markers represent an invaluable tool for stem cell isolation. Nonetheless their role, if any, in stem cell biology is poorly investigated. Functions of stem cells, however, depend on niche external cues, which reach cells through surface markers. We addressed the role of SSEA‐3 in MUSE cell behaviour, trying to define whether SSEA‐3 is just a marker or if it plays a functional role in this cell population by determining if it has any relationship with FGF2 activity.ResultsWe evidenced how the SSEA‐3 and FGF2 cooperation affected the self‐renewal and clonogenic capacity of MUSE cells. The block of SSEA‐3 significantly reduced the multilineage potential of MUSE cells with production of nullipotent clones.ConclusionsWe contributed to dissecting the mechanisms underlying MUSE cell properties for establishing successful stem‐cell‐based therapies and the promotion of MUSE cells as a tool for the in vitro disease model.

We demonstrated that SSEA‐3, a glycosphingolipid (GSL), may act as an FGF‐2 co‐receptor in MUSE cell, this activates the FGF2 signalling cascade mainly through PI3K mediation. Our study is one of the first evidence attributing GSL a functional role in governing stem cell biology. (A) Experimental plan. (B) Effect of cultivation of MUSE cells with SSEA3 inhibition. (C) SSEA‐3—FGF2 interaction and pathway.     

Split Gp41-1 intein splicing as a model to evaluate the cellular location of the oncosuppressor Maspin in an in vitro model of osteosarcoma

Inteins are proteins involved in the protein splicing mechanism, an autoprocessing event, where sequences (exteins) separated by inteins become ligated each other after recombination. Two kinds of inteins have been described, contiguous inteins and split inteins. The former ones are transcribed and translated as a single peptide along with their exteins, while the latter are fragmented between two different genes and are transcribed and translated separately. The aim of this study is to establish a method to obtain a fluorescent eukaryotic protein to analyze its cellular localization, using the natural split gp41-1 inteins. We chose natural split inteins due to their distribution in all three domains of life. Two constructs were prepared, one containing the N-terminal split intein along with the N-moiety of the Red Fluorescent Protein (RFP) and a second construct containing the C-terminal of split intein, the C-moiety of RFP and the gene coding for Maspin, a tumor suppressor protein. The trans-splicing was verified by transfecting both N-terminal and C-terminal constructs into mammalian cells. The success of the recombination event was highlighted through the fluorescence produced by reconstituted RFP after recombination, along with the overlap of the red fluorescence produced by recombined RFP and the green fluorescence produced by the hybridization of the recombinant Maspin with a specific antibody. In conclusion, we opted to use this mechanism of recombination to obtain a fluorescent Maspin instead to express a large fusion protein, considering that it could interfere with Maspin's structure and function.     

Transmural distribution of iron in the hypoxic and reoxygenated rabbit left ventricular myocardium

Transmural distribution of low molecular weight iron (LMWI), total iron, and protein carbonyls (PC) was investigated in the perfused rabbit heart under aerobic conditions, and after 60 min hypoxia followed or not by 3 min reoxygenation. In the aerobic perfused hearts, LMWI, total iron and PC did not show significant transmural differences. Hypoxia increased LMWI and PC levels, which were significantly higher in the subendocardium than in the subepicardium; further significant changes were not observed after reoxygenation. Total iron showed no transmural difference and was not significantly affected by both hypoxia and reoxygenation. Free iron was undetectable in the myocardial effluent of all experimental groups. Thus, hypoxia favors myocardial iron decompartmentalisation and oxidative stress, which are significantly greater in the inner than in the outer ventricular layers. Such findings may add further insight into the problem of the vulnerability of the mammalian subendocardium to injury induced by oxygen deprivation.     

Influence of the Environment on the Morphological and Biochemical Characteristics of Different Aspergillus niger Wild Type Strains

The present work studied the differences in accumulation, transformation and volatilization of different heavy metals ions on molecular and macromorphological features of Aspergillus niger wild type strains. Four different strains of A. niger (An) were used. Three strains (An-P, An-N, An-S) were isolated from acid and ultra acid mining regions with higher concentration of As and Sb. The fourth strain (An-G) was used as the comparative one. Environmental burden strongly affected biochemical, macro and micromorphological characteristics of studied strains. The RAMP profiles showed 90 % similarity among the studied strains. The strain An-S showed its own characteristic RAMP profile, different to the others ones. Analyzed strains can be clustered into two groups on the basis of the changes in gene expression and morphological parameters. Differences were found in both acid β-1,3-glucanases and peroxidases. Main quantitative and qualitative differences by A-PAGE and SDS-PAGE were registered for proteins with Mr ~ 50; 34; 28–27 and 11 kDa. Presence of living mutants of A. niger strains in old environmental burden indicate on the adaptation and mutation processes of soil microorganisms from the point of long-term effect.     

Silver derivatives of tris(pyrazol-1-yl)methanes. A silver(I) nitrate complex containing a tris(pyrazolyl)methane coordinated in a bridging mode

The reaction of AgX (X=ClO₄, NO₃ or SO₃CH₃) acceptors with excesses of tris(pyrazol-1-yl)methane ligands L (L=CH(pz)₃, CH(4-Mepz)₃, CH(3,5-Me₂pz)₃, CH(3,4,5-Me₃pz)₃ or CH(3-Mepz)₂(5-Mepz)) yields 1:1 [AgX(L)], 2:1 [Ag(L)₂]X or 3:2 [(AgX)₂(L)₃] complexes. The ligand to metal ratio in all complexes is dependent on the number and disposition of the Me substituents on the azole ring of the neutral ligand and on the nature of the Ag(I) acceptor. All complexes have been characterized in the solid state as well as in solution (medium- and far-IR, ¹H and ¹³C NMR and conductivity determinations) and the solid-state structures of [Ag(NO₃){(pz)₃CH}]_(∞/∞) and [Ag{(3,5-Me₂pz)₃CH}₂]NO₃ determined by single crystal X-ray studies.