Effectiveness of a microbial formula,as a bioaugmentation agent,tailored for bioremediation of diesel oil and heavy metal co-contaminated soil

The activation of natural bioremediation potentials is the challenge that research is currently addressing for overcoming bottlenecks still affecting bioremediation applications. Bioaugmentation is one possible way to activate such natural potentials, provided that the biodiversity introduced to increase catabolically relevant capacity is identified also considering the ecological context. The present work deals with bioaugmentation aimed at the remediation of a soil co-contaminated (spiked) with both diesel oil (1%, v/w), and heavy metals (Pb and Zn), using intact soil core microcosms in different experimental conditions. We supposed that both heavy metal resistance and active metabolism towards organic pollutants are essential metabolic traits to trap the energetic flux, which drives the microbial community towards biodegradation under the given experimental conditions. Consequently, the bioaugmentation was performed by introducing a tailor made microbial formula composed of 12 allochthonous strains. They belong to a stable population previously isolated from a chronic polluted site and are both hydrocarbon degraders and heavy metal resistant and, also, compatible with the autochthonous microbial community. The active role of the microbial formula in pushing the entire community towards an effective bioremediation of diesel oil close to 75%, in the presence of bioavailable metals, has been proven through hydrocarbons analysis, metabolic and molecular profiling at community level (Biolog system, DGGE).     

N-glycosylation of the mammalian dipeptidyl aminopeptidase-like protein 10 (DPP10) regulates trafficking and interaction with Kv4 channels

The dipeptidyl aminopeptidase-like protein 10 (DPP10) is a type II transmembrane protein homologue to the serine protease DPPIV/CD26 but enzymatically inactive. In the mammalian brain, DPP10 forms a complex with voltage-gated potassium channels of the Kv4 family, regulating their cell surface expression and biophysical properties. DPP10 is a glycoprotein containing eight predicted N-glycosylation sites in the extracellular domain. In this study we investigated the role of N-glycosylation on DPP10 trafficking and functional activity. Using site-directed mutagenesis (N to Q) we showed that N-glycosylation occured at six positions. Glycosylation at these specific residues was necessary for DPP10 trafficking to the plasma membrane as observed by flow cytometry. The surface expression levels of the substitutions N90Q, N119Q, N257Q and N342Q were reduced by more than 60%. Hence the interaction with the Kv4.3/KChIP2a channel complex was disrupted preventing the hastening effect of wild type DPP10 on current kinetics. Interestingly, N257 was crucial for this function and its substitution to glutamine completely blocked DPP10 sorting to the cell surface and prevented DPP10 dimerization. In summary, we demonstrated that glycosylation was necessary for both DPP10 trafficking to the cell surface and functional interaction with Kv4 channels.     

A case of primary selective hypoaldosteronism carrying three mutations in the aldosterone synthase (Cyp11b2) gene

An infant with a clinical phenotype of early onset hypoaldosteronism has been screened for mutation analysis of the Cyp11b2 gene encoding aldosterone synthase enzyme. We have described a novel nonsense mutation in exon 3 (c.508C>T) that gave rise to a shorter protein (Q170X) and two known concurrent missense mutations (c.594A>C in exon 3 and c.1157T>C in exon 7) that led to substitution of glutamic acid for aspartic acid at amino acid position 198 (E198D) and of valine for alanine at amino acid position 386 (V386A). The father, who carried E198D plus V386A mutations, showed a fractional sodium excretion of 1.25% that was unmodified by dietary salt restriction, suggesting a mild haploinsufficiency. We examined by in silico analysis the effect of the mutations on the secondary and tertiary structures of aldosterone synthase to explain the inefficient enzymatic activity. The Q170X mutation produced a truncated protein, which was consequently associated with a loss of catalytic activity. As predicted by JPred web system and Dock 6.3 software, the concurrent expression of E198D and V386A mutations induced a significant secondary structure rearrangement and a shift of the heme group and the 18-hydroxycorticosterone substrate from their optimal placement.     

A case of primary selective hypoaldosteronism carrying three mutations in the aldosterone synthase (Cyp11b2) gene

An infant with a clinical phenotype of early onset hypoaldosteronism has been screened for mutation analysis of the Cyp11b2 gene encoding aldosterone synthase enzyme. We have described a novel nonsense mutation in exon 3 (c.508 C > T) that gave rise to a shorter protein (Q170X) and two known concurrent missense mutations (c.594A > C in exon 3 and c.1157 T > C in exon 7) that led to substitution of glutamic acid for aspartic acid at amino acid position 198 (E198D) and of valine for alanine at amino acid position 386 (V386A). The father, who carried E198D plus V386A mutations, showed a fractional sodium excretion of 1.25% that was unmodified by dietary salt restriction, suggesting a mild haploinsufficiency.     

16q22.1 microdeletion detected by array-CGH in a family with mental retardation and lobular breast cancer

We describe the case of a boy with psychomotor delay and dysmorphic features, with a germline 16q22.1 microdeletion identified by array-CGH. The deletion spans 0.24Mb and encompasses three genes (ZFP90, CDH3 and CDH1). The deletion has been demonstrated to be inherited from his mother who was affected by lobular breast cancer (LBC) without any other apparently phenotypic features. We suppose that the microdeletion, in particular ZFP90 which is cerebrally expressed, is causative for the boy's phenotype. Mental retardation in the affected boy can recognize several mechanisms such as variable expressivity, non-penetrance, multifactorial/polygenic inheritance, recessive inheritance, a second rearrangement event and epigenetics. Furthermore, we suggest that the deletion of the CDH1, a tumor suppressor gene, involved in hereditary diffuse gastric cancer (HDGC) and LBC predisposed the mother to the carcinoma.     

Rapid expansion of an enhanced stock of chum salmon and its impacts on wild population components

A harvested stock of chum salmon homing to Kurilskiy Bay, Iturup Island, consists of two genetically distinct river populations that reproduce in two rivers that drain into the bay and are characterized by limited gene flow. One of these is small and can be regarded as wild, whereas the other is much larger and, until recently, was composed of naturally reproducing components spawning in the river??s mainstem and tributaries, with almost no hatchery reproduction during the past two decades. The only human impact on reproduction of the chum salmon stock was regulation of the escapement, with officially accepted limits to avoid ??over-escapement??. Recently the hatchery began to release a large amount of chum salmon juveniles. As confirmed by data on variation in both age composition and microsatellite DNA, first-generation hatchery-origin fish that returned from the first large releases occupied spawning grounds and presumably competed directly with, and potentially displaced wild fish. The most dramatic example is a genetically distinct beach-spawning form of chum salmon that was swamped by much more numerous hatchery-origin fish of the river-spawning form. In order to restore and support naturally reproduced population components, careful estimation of the carrying capacity of natural spawning grounds is necessary with efforts to increase escapement to these habitats. We also recommend concerted efforts to restore and conserve a unique beach-spawning population of chum salmon. We further recommend development of a marking program for direct estimation of straying and evaluation of ecological and genetic impacts of hatchery fish on neighboring wild and natural populations.     

A potential role of Escherichia coli pathobionts in the pathogenesis of pediatric inflammatory bowel disease

Through genomic analysis of mucosa-associated Escherichia coli strains, we found a close genetic association among isolates from pediatric inflammatory bowel disease (IBD) patients. A specific E. coli pathovar, adherent-invasive E. coli (AIEC), was found in Crohn's disease (CD) adult patients - this pathovar has enhanced adhesive and invasive properties, mainly due to the mannose-bonding FimH protein. We aimed to characterize 52 mucosa-associated E. coli strains isolated from pediatric IBD and non-IBD patients. Eleven E. coli strains, showing a strong similarity in fimH gene sequence to that of E. coli AIEC LF82, were characterized for fimH gene sequence, genomic profiling, adhesive and invasive ability, and phylogrouping. The results were compared with E. coli strains AIEC LF82 and MG1655. The 11 E. coli isolates showed 82.4% ± 1.4% fimH sequence similarity and 80.6% ± 1.3% genomic similarity to strain AIEC LF82. All these strains harbored V27A and S78N FimH mutations, as found in LF82. Nine of them belonged to the more virulent B2 and D phylogroups. Neuraminidase treatment, mimicking inflamed mucosa, enhanced adhesion of all 11 strains by 3.5-fold, but none showed invasion ability. It could be argued that the 11 selected strains could be a branch of an E. coli subpopulation (pathobionts), that could take advantage in an inflamed context because of a suitable genomic and (or) genetic backdrop.     

IQGAP2, A candidate tumour suppressor of prostate tumorigenesis

Loss of IQGAP2 contributes to the tumorigenesis of hepatocellular carcinoma and gastric cancer. However, whether IQGAP2 also suppresses prostate tumorigenesis remains unclear. We report here that IQGAP2 is a candidate tumour suppressor of prostate cancer (PC). Elevated IQGAP2 was detected in prostatic intraepithelial neoplasia (PIN), early stages of PCs (Gleason score ≤3), and androgen-dependent LNCaP PC cells. However, IQGAP2 was expressed at substantially reduced levels not only in prostate glands and non-tumorigenic BPH-1 prostate epithelial cells but also in advanced (Gleason score 4 or 5) and androgen-independent PCs. Furthermore, xenograft tumours that were derived from stem-like DU145 cells displayed advanced features and lower levels of IQGAP2 in comparison to xenograft tumours that were produced from non stem-like DU145 cells. Collectively, these results suggest that IQGAP2 functions in the surveillance of prostate tumorigenesis. Consistent with this concept, ectopic IQGAP2 reduced the proliferation of DU145, PC3, and 293T cells as well as the invasion ability of DU145 cells. While ectopic IQGAP2 up-regulated E-cadherin in DU145 and PC3 cells, knockdown of IQGAP2 reduced E-cadherin expression. In primary PC and DU145 cells-derived xenograft tumours, the majority of tumours with high levels of IQGAP2 were strongly-positive for E-cadherin. Therefore, IQGAP2 may suppress PC tumorigenesis, at least in part, by up-regulation of E-cadherin. Mechanistically, overexpression of IQGAP2 significantly reduced AKT activation in DU145 cells and inhibition of AKT activation upregulated E-cadherin, suggesting that IQGAP2 increases E-cadherin expression by inhibiting AKT activation. Taken together, we demonstrate here that IQGAP2 is a candidate tumour suppressor of PC.     

Crosstalk between the ubiquitin-proteasome system and autophagy in a human cellular model of Alzheimer's disease

Alzheimer's disease is the most common progressive neurodegenerative disorder characterized by the abnormal deposition of amyloid plaques, likely as a consequence of an incorrect processing of the amyloid-β precursor protein (AβPP). Dysfunctions in both the ubiquitin-proteasome system and autophagy have also been observed. Recently, an extensive cross-talk between these two degradation pathways has emerged, but the exact implicated processes are yet to be clarified. In this work, we gained insight into such interplay by analyzing human SH-SY5Y neuroblastoma cells stably transfected either with wild-type AβPP gene or 717 valine-to-glycine AβPP-mutated gene. The over-expression of the AβPP mutant isoform correlates with an increase in oxidative stress and a remodeled pattern of protein degradation, with both marked inhibition of proteasome activities and impairment in the autophagic flux. To compensate for this altered scenario, cells try to promote the autophagy activation in a HDAC6-dependent manner. The treatment with amyloid-β(42) oligomers further compromises proteasome activity and also contributes to the inhibition of cathepsin-mediated proteolysis, finally favoring the neuronal degeneration and suggesting the existence of an Aβ(42) threshold level beyond which proteasome-dependent proteolysis becomes definitely dysfunctional.     

Continuous occurrence of intra-individual chromosome rearrangements in the peach potato aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae)

Analysis of the holocentric mitotic chromosomes of the peach-potato aphid, Myzus persicae (Sulzer), from clones labelled 50, 51 and 70 revealed different chromosome numbers, ranging from 12 to 14, even within each embryo, in contrast to the standard karyotype of this species (2n?=?12). Chromosome length measurements, combined with fluorescent in situ hybridization experiments, showed that the observed chromosomal mosaicisms are due to recurrent fragmentations of chromosomes X, 1 and 3. Contrary to what has generally been reported in the literature, X chromosomes were frequently involved in recurrent fragmentations, in particular at their telomeric ends opposite to the nucleolar organizer region. Supernumerary B chromosomes have been also observed in clones 50 and 51. The three aphid clones showed recurrent fissions of the same chromosomes in the same regions, thereby suggesting that the M. persicae genome has fragile sites that are at the basis of the observed changes in chromosome number. Experiments to induce males also revealed that M. persicae clones 50, 51 and 70 are obligately parthenogenetic, arguing that the reproduction by apomictic parthenogenesis favoured the stabilization and inheritance of the observed chromosomal fragments.