Bacterial Communities Involved in Soil Formation and Plant Establishment Triggered by Pyrite Bioweathering on Arctic Moraines

In arctic glacier moraines, bioweathering primed by microbial iron oxidizers creates fertility gradients that accelerate soil development and plant establishment. With the aim of investigating the change of bacterial diversity in a pyrite-weathered gradient, we analyzed the composition of the bacterial communities involved in the process by sequencing 16S rRNA gene libraries from different biological soil crusts (BSC). Bacterial communities in three BSC of different morphology, located within 1 m distance downstream a pyritic conglomerate rock, were significantly diverse. The glacier moraine surrounding the weathered site showed wide phylogenetic diversity and high evenness with 15 represented bacterial classes, dominated by Alphaproteobacteria and pioneer Cyanobacteria colonizers. The bioweathered area showed the lowest diversity indexes and only nine bacterial families, largely dominated by Acidobacteriaceae and Acetobacteraceae typical of acidic environments, in accordance with the low pH of the BSC. In the weathered BSC, iron-oxidizing bacteria were cultivated, with counts decreasing along with the increase of distance from the rock, and nutrient release from the rock was revealed by environmental scanning electron microscopy-energy dispersive X-ray analyses. The vegetated area showed the presence of Actinomycetales, Verrucomicrobiales, Gemmatimonadales, Burkholderiales, and Rhizobiales, denoting a bacterial community typical of developed soils and indicating that the lithoid substrate of the bare moraine was here subjected to an accelerated colonization, driven by iron-oxidizing activity.     

Analysis of hepatitis C virus hypervariable region 1 sequence from cryoglobulinemic patients and associated controls

Chronic hepatitis C virus (HCV) infection is frequently associated with extrahepatic manifestations, including nonmalignant and malignant B-cell lymphoproliferative disorders. It has been reported that specific changes or recurring motifs in the amino acid sequence of the HCV hypervariable region 1 (HVR1) may be associated with cryoglobulinemia. We searched for specific insertions/deletions and/or amino acid motifs within HVR1 in samples from 80 symptomatic and asymptomatic patients with and 33 patients without detectable cryoglobulins, all with chronic HCV infection. At variance with the results of a previous study which reported a high frequency of insertions at position 385 of HVR1 from cryoglobulinemic patients, we found a 6.2% prevalence of insertions in samples from patients with and a 9.1% prevalence in those without cryoglobulinemia. Moreover, statistical and bioinformatics approaches including Fisher's exact test, k-means clustering, Tree determinant-residue identification, correlation of mutations, principal component analysis, and phylogenetic analysis failed to show statistically significant differences between sequences from cryoglobulin-negative and -positive patients. Our findings suggest that cryoglobulinemia may arise by virtue of as-yet-unidentified host- rather than virus-specific factors. Specific changes in HCV envelope sequence distribution are unlikely to be directly involved in the establishment of pathological B-cell monoclonal proliferation.     

Soluble RAGE in type 2 diabetes: association with oxidative stress

Advanced glycation end products (AGEs) contribute to diabetic vascular complications by engaging the AGE receptor (RAGE). A soluble RAGE form (sRAGE) acts as a decoy domain receptor, thus decreasing AGE cellular binding. A cross-sectional comparison of sRAGE, asymmetric dimethylarginine (ADMA) plasma levels (index of endothelial dysfunction), and urinary 8-iso-prostaglandin (PG)F(2alpha) (marker of oxidative stress) was performed between 86 diabetic patients and 43 controls. Plasma sRAGE levels were significantly lower and ADMA levels were significantly higher in diabetic patients as compared to controls (P<0.0001). HbA1c and urinary 8-iso-PGF(2alpha) were correlated inversely with sRAGE and directly with ADMA. On multivariate analysis HbA1c was independently related to sRAGE levels in diabetic patients. Twenty-four of 86 patients with newly diagnosed diabetes and 12 patients in poor metabolic control were reevaluated after treatment with a hypoglycemic agent or insulin, respectively. Improvement in metabolic control by oral agents or insulin resulted in a significant increase in sRAGE and decrease in ADMA levels (P<0.0001). Thus, poor glycemic control reduces sRAGE levels, in association with enhanced oxidative stress and endothelial dysfunction in diabetes. These abnormalities are susceptible to modulation by improvement in metabolic control.     

Membrane-Sensitive Conformational States of Helix 8 in the Metabotropic Glu2 Receptor, a Class C GPCR

The recent elucidation of the X-ray structure of several class A GPCRs clearly indicates that the amphipathic helix 8 (H8) is a conserved structural domain in most crystallized GPCRs. Very little is known about the presence and the possible role of an analogous H8 domain in the distantly related class C GPCRs. In this study, we investigated the structural properties for the H8 domain of the mGluR2 receptor, a class C GPCR, by applying extended molecular dynamics simulations. Our study indicates that the amphipathic H8 adopts membrane-sensitive conformational states, which depend on the membrane composition. Cholesterol-rich membranes stabilize the helical structure of H8 whereas cholesterol-depleted membranes induce a disruption of H8. The observed link between membrane cholesterol levels and H8 conformational states suggests that H8 behaves as a sensor of cholesterol concentration.     

Early angiogenic response to shock waves in a three-dimensional model of human microvascular endothelial cell culture (HMEC-1)

The exact nature of shock wave (SW) action is not, as yet, fully understood, although a possible hypothesis may be that shock waves induce neoangiogenesis. To test this hypothesis, a three-dimensional (3D) culture model on Matrigel was developed employing a human microvascular endothelial cell line (HMEC-1) which was stimulated with low energy soft- focused SW generated by an SW lithotripter. After 12 hours we observed a statistically significant increase in capillary connections subsequent to shock-wave treatment in respect to the control group and a marked 3-hour down-regulation in genes involved in the apoptotic processes (BAX, BCL2LI, GADD45A, PRKCA), in cell cycle (CDKN2C, CEBPB, HK2, IRF1, PRKCA), oncogenes (JUN, WNT1), cell adhesion (ICAM-1), and proteolytic systems (CTSD, KLK2, MMP10). Our preliminary results indicate that microvascular endothelial cells in vitro quickly respond to SW, proliferating and forming vessel-like structures, depending on the energy level employed and the number of shocks released. The early decreased expression in the analysed genes could be interpreted as the first reactive response of the endothelial cells to the external stimuli and the prelude to the events characterizing the neo-angiogenic sequence.     

A new sigma ligand, (+/-)-PPCC, antagonizes kappa opioid receptor-mediated antinociceptive effect

The compound (1R,2S/1S,2R)-2-[4-hydroxy-4-phenylpiperidin-1-yl)methyl]-1-(4-methylphenyl) cyclopropanecarboxylate [(+/-)-PPCC] is a ligand with high affinity for sigma (sigma) sites of which the selectivity towards several other receptor systems has been demonstrated. Given the existence of a relationship between the sigma system and the kappa opioid (KOP)-mediated analgesia, to characterize the pharmacological properties of (+/-)-PPCC we analyzed its influence on the analgesic effect of the systemic injected kappa agonist (-)-U-50,488H comparing the effects with those shown by (+)-pentazocine and BD1047. The results demonstrate that the systemic administration of (+/-)-PPCC (1 mg/kg s.c.) does not modify basal tail-flick latency. Pre-treatment with (+/-)-PPCC, at the same dose, significantly decreased the antinociceptive effect of (-)-U-50,488H, analogously to the sigma compounds used. This study confirms that (+/-)-PPCC plays the role of sigma agonist in this model and strengthens the hypothesis of the sigma receptor modulatory role on KOP-mediated analgesia.     

Interleukin-18 and gestosis: correlation with Helicobacter pylori seropositivity

The aim of this brief communication was to determine the correlation between pre-eclampsia (PE), Helicobacter pylori pathogenic strains seropositivity, and interleukin-18 (IL-18) levels. To this purpose 25 pre-eclamptic women and 25 healthy parturient women of similar age were evaluated for: IL-18 levels, by ELISAH. pylori seropositivity, by anti-IgG ELISAAnti-Cag-A antibodies using a commercial immunoblot assay.We report similar values of IL-18 in our pre-eclamptic patients and in healthy parturient women (respectively 350 +/- 150 vs. 399 +/- 132 pg ml(-1); p = 0.23). However the seropositivity for H. pylori was 84 and 32% (p < 0.001), and anti-Cag-A antibodies were present respectively in 80 and 28% of the two populations. On the basis of our data we hypothesize that H. pylori infection from Cag-A strains can be involved in some cases of PE and that the microorganism could modulate IL-18 release. In fact, differences on IL-18 production have been described by different authors between pre-eclamptic and healthy pregnant women, independently from infective pathology.     

In vivo evaluation of (+)-MR200 as a new selective sigma ligand modulating MOP, DOP and KOP supraspinal analgesia

The compound (+)-MR200 [(+)-methyl (1R,2S)-2-{[4-(4-chlorophenyl)-4-hydroxypiperidin-1-yl]methyl}-1-phenylcyclopropanecarboxylate] is a sigma ligand with increased affinity and selectivity compared to the structurally related ligand haloperidol. From the results of a previous study on the modulation of a systemically injected KOP opioid agonist analgesia by (+)-MR200, we analysed the influence of this sigma ligand on the antinociceptive effect of centrally injected MOP, DOP, and KOP selective agonists using the tail-flick test in rats. The results obtained confirmed that systemic administration of (+)-MR200 (1mg/Kg s.c.) did not modify basal tail-flick latency. Pre-treatment with 1mg/Kg s.c. of (+)-MR200 provided a significant increase in the antinociceptive effect of DAMGO (100ng/rat i.c.v.) and DPDPE (20 microg/rat i.c.v.). Conversely to previous reports, pre-treatment with (+)-MR200 reversed, in these experimental conditions, U-50488H (100 microg/rat i.c.v.) analgesia. The mechanism involved in these effects was not clear, but provided additional data on a diverging modulator role of selective sigma-1 antagonists on KOP analgesia.     

Trafficking and postsecretory events responsible for the formation of secreted human salivary peptides: a proteomics approach

To elucidate the localization of post-translational modifications of different classes of human salivary proteins and peptides (acidic and basic proline-rich proteins (PRPs), Histatins, Statherin, P-B peptide, and "S type" Cystatins) a comparative reversed phase HPLC-ESI-MS analysis on intact proteins of enriched granule preparations from parotid and submandibular glands as well as parotid, submandibular/sublingual (Sm/Sl), and whole saliva was performed. The main results of this study indicate the following. (i) Phosphorylation of all salivary peptides, sulfation of Histatin 1, proteolytic cleavages of acidic and precursor basic PRPs occur before granule storage. (ii) In agreement with previous studies, basic PRPs are secreted by the parotid gland only, whereas all isoforms of acidic PRPs (aPRPs) are secreted by both parotid and Sm/Sl glands. (iii) Phosphorylation levels of aPRPs, Histatin 1, and Statherin are higher in the parotid gland, whereas the extent of cleavage of aPRP is higher in Sm/Sl glands. (iv) O-Sulfation of tyrosines of Histatin 1 is a post-translational modification specific for the submandibular gland. (v) The concentration of Histatin 3, Histatin 5, and Histatin 6, but not Histatin 1, is higher in parotid saliva. (vi) Histatin 3 is submitted to the first proteolytic cleavage (generating Histatins 6 and 5) during granule maturation, and it occurs to the same relative extent in both glands. (vii) The proteolytic cleavages of Histatin 5 and 6, generating a cascade of Histatin 3 fragments, take place after granule secretion and are more extensive in parotid secretion. (viii) Basic PRPs are cleaved in the oral cavity by unknown peptidases, generating various small proline-rich peptides. (ix) C-terminal removal from Statherin is more extensive in parotid saliva. (x) P-B peptide is secreted by both glands, and its relative quantity is higher in submandibular/sublingual secretion. (xi) In agreement with previous studies, S type Cystatins are mainly the product of Sm/Sl glands.