322 research outputs found

    Survey on fungal, parasites and epibionts infestation on the Astacus leptodactylus (Eschscholtz, 1823), in Aras Reservoir West Azarbaijan, Iran

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    A total of 394 (255 males, 139 females) live freshwater crayfish Astacus leptodactylus from four stations of Aras reservoir in West Azarbaijan Province (North-Western Iran) were studied during the winter until early autumn of 2009 for the presence of parasites, epibionts and fungal agents. Parasitological surveys were carried out on gills, exoskeleton and internal organs, mycological examinations on the exoskeleton (the legs, abdominal cuticle and the eggs). 9 epibionts and parasites peritrich protozoans including: Cothurnia sieboldii (68.5%), Zoothamnium spp. (56.6%), Vorticella similis (45.6%), Chilodonella spp. (0.5%), Podophrya fixa (7.8%), Epistylis chrysemidis (53.2%), Pyxicola annulata (66%), Opercularia articulata (19.8%), Tetrahymena pyriformis (0.5%) were recorded. From Metazoan parasites group, Branchiobdella kozarovi (71%) as the first observation was the only parasite recorded from exoskeleton with prevalence (100%) during spring and summer of the study year. Infected gills were heavily damaged with Aeolosoma hemprichi (Annelid) in winter with 90% prevalence. Other epibiont fouling organisms such as Rotatoria, free living Nematods were observed in this survey. Furthermore, on the mycotic agents identified Penicillium expansum, Aspergillus flavus, Alternaria sp., Fusarium sp. and Saprolegnia sp. were isolated in IM media and identified with slides cultured from cuticular melanized lesions and eggs of infected specimens. This is the first investigation on epibionts, parasites and fungal organisms of the endemic crayfish in Aras reservoir, Iran

    Hormone-Induced 14-3-3γ Adaptor Protein Regulates Steroidogenic Acute Regulatory Protein Activity and Steroid Biosynthesis in MA-10 Leydig Cells

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    Cholesterol is the sole precursor of steroid hormones in the body. The import of cholesterol to the inner mitochondrial membrane, the rate-limiting step in steroid biosynthesis, relies on the formation of a protein complex that assembles at the outer mitochondrial membrane called the transduceosome. The transduceosome contains several mitochondrial and cytosolic components, including the steroidogenic acute regulatory protein (STAR). Human chorionic gonadotropin (hCG) induces de novo synthesis of STAR, a process shown to parallel maximal steroid production. In the hCG-dependent steroidogenic MA-10 mouse Leydig cell line, the 14-3-3γ protein was identified in native mitochondrial complexes by mass spectrometry and immunoblotting, and its levels increased in response to hCG treatment. The 14-3-3 proteins bind and regulate the activity of many proteins, acting via target protein activation, modification and localization. In MA-10 cells, cAMP induces 14-3-3γ expression parallel to STAR expression. Silencing of 14-3-3γ expression potentiates hormone-induced steroidogenesis. Binding motifs of 14-3-3γ were identified in components of the transduceosome, including STAR. Immunoprecipitation studies demonstrate a hormone-dependent interaction between 14-3-3γ and STAR that coincides with reduced 14-3-3γ homodimerization. The binding site of 14-3-3γ on STAR was identified to be Ser-194 in the STAR-related sterol binding lipid transfer (START) domain, the site phosphorylated in response to hCG. Taken together, these results demonstrate that 14-3-3γ negatively regulates steroidogenesis by binding to Ser-194 of STAR, thus keeping STAR in an unfolded state, unable to induce maximal steroidogenesis. Over time 14-3-3γ homodimerizes and dissociates from STAR, allowing this protein to induce maximal mitochondrial steroid formation

    Lived experiences of patients suffering from acute Old World Cutaneous Leishmaniasis: A qualitative content analysis study from Iran

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    Background: The aim of this study was to explore the experiences of patients who suffer from acute cutaneous leishmaniasis in Iran, focusing on quality of life. Methods: The study was conducted at two different sites in Iran in 2010-2011. Individual in-depth interviews were conducted with six men and six women parasitologically confirmed acute cutaneous leishmaniasis. Interviews were recorded, transcribed verbatim, and translated into English. Qualitative content analysis was used for data analysis. Results: The participants, aged 23 to 63yr, had mild to severe disease. Based on the analysis four main themes were developed. "Fearing an agonizing disease" reflects patients' experiences of disease development resulting in sadness and depression, "struggling to cope" and "taking on the blame" both illustrate how patients experience living with the disease, which included both felt and enacted stigma as major social concerns. "Longing for being seen and heard" refers to patients' experiences with healthcare as well as their expectations and demands from communities and healthcare to be involved in closing the knowledge and awareness gap. Conclusion: Mental and social dimensions of cutaneous leishmaniasis were complex and adversely affected patients' lives by causing psychological burden and limiting their social interactions. Health authorities have to plan programs to increase the disease awareness to prevent the existing stigma to improve patients' social condition and medical care. © 2018, Tehran University of Medical Sciences

    Laboratory comparison of aging characteristics of warm mix asphalts involving natural and synthetic water containing additives

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    When comparing the aging characteristics of hot and warm mix asphalts from a technical point of view, it can intuitively be expected that a warm mix asphalt would be less subjected to aging-induced failures due to lower application temperatures. Since the side effects of warm asphalt technology should be investigated distinctly. This study addresses the aging investigation of properties of bituminous mixtures containing two (i.e., natural and synthetic zeolite) water based additives available on the market. Within the scope of this study, short- and long-term aging conditions were simulated on mixtures containing various contents of additives as well as on control specimens. The aging indices were determined based on the hardness ratio employing indirect tensile strength values in order to investigate the aging induced failures betide by time. Aging indices showed that the specimens with water containing additives demonstrate relatively better resistance against hardening than conventional hot mix asphalt specimens

    Chimeric 14-3-3 proteins for unraveling interactions with intrinsically disordered partners

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    In eukaryotes, several "hub" proteins integrate signals from different interacting partners that bind through intrinsically disordered regions. The 14-3-3 protein hub, which plays wide-ranging roles in cellular processes, has been linked to numerous human disorders and is a promising target for therapeutic intervention. Partner proteins usually bind via insertion of a phosphopeptide into an amphipathic groove of 14-3-3. Structural plasticity in the groove generates promiscuity allowing accommodation of hundreds of different partners. So far, accurate structural information has been derived for only a few 14-3-3 complexes with phosphopeptide-containing proteins and a variety of complexes with short synthetic peptides. To further advance structural studies, here we propose a novel approach based on fusing 14-3-3 proteins with the target partner peptide sequences. Such chimeric proteins are easy to design, express, purify and crystallize. Peptide attachment to the C terminus of 14-3-3 via an optimal linker allows its phosphorylation by protein kinase A during bacterial co-expression and subsequent binding at the amphipathic groove. Crystal structures of 14-3-3 chimeras with three different peptides provide detailed structural information on peptide-14-3-3 interactions. This simple but powerful approach, employing chimeric proteins, can reinvigorate studies of 14-3-3/phosphoprotein assemblies, including those with challenging low-affinity partners, and may facilitate the design of novel biosensors

    Negative emotions set in motion : the continued relevance of #GamerGate

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    This chapter aims at making sense of the #GamerGate (#GG) online harassment campaign that was particularly active in 2014–2015 but to this day continues to produce hateful speech against certain ideologies and minorities in gaming culture. The campaign was especially successful at building online visibility through harassment, and the affective resonances of the issues it raised have since translated into general online campaigning how-to’s, financial earnings, and even political action outside of the gaming sphere. Although the primary breeding ground for this movement was 4chan (and later, 8chan), it only reached public awareness and visibility – hence, effectiveness – through Twitter and, to a lesser extent, through YouTube. In order to understand the emotional charge and political relevance of this campaign, we rely on both quantitative and qualitative activity analyses of the Twitter users that use the hashtag #GamerGate between 2014 and 2019. In addition to analyzing who were the most active tweeters and what kind of resonance their tweets elicited, we looked into the emotional qualities of their communication. The communication strategies of #GG tweeters took advantage of the language and cultural references of the target demographic to drive a set of topics into public discourse and, further, to political activism. This discourse utilized a combination of affective modes, based mainly on resentment and schadenfreude, that we see echoing in many places on the internet. In the end, we argue that while #GG may have been only one instance of a campaign with harassment elements, the sentiments it cultivated and amplified as well as its operational logics have since been successfully employed in many similar online movements, including the current political campaigning associated with the so-called alt-right.fi=vertaisarvioitu|en=peerReviewed

    Vav3 oncogene activates estrogen receptor and its overexpression may be involved in human breast cancer

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    <p>Abstract</p> <p>Background</p> <p>Our previous study revealed that Vav3 oncogene is overexpressed in human prostate cancer, activates androgen receptor, and stimulates growth in prostate cancer cells. The current study is to determine a potential role of Vav3 oncogene in human breast cancer and impact on estrogen receptor a (ERα)-mediated signaling axis.</p> <p>Methods</p> <p>Immunohistochemistry analysis was performed in 43 breast cancer specimens and western blot analysis was used for human breast cancer cell lines to determine the expression level of Vav3 protein. The impact of Vav3 on breast cancer cell growth was determined by siRNA knockdown of Vav3 expression. The role of Vav3 in ERα activation was examined in luciferase reporter assays. Deletion mutation analysis of Vav3 protein was performed to localize the functional domain involved in ERα activation. Finally, the interaction of Vav3 and ERα was assessed by GST pull-down analysis.</p> <p>Results</p> <p>We found that Vav3 was overexpressed in 81% of human breast cancer specimens, particularly in poorly differentiated lesions. Vav3 activated ERα partially via PI3K-Akt signaling and stimulated growth of breast cancer cells. Vav3 also potentiated EGF activity for cell growth and ERα activation in breast cancer cells. More interestingly, we found that Vav3 complexed with ERα. Consistent with its function for AR, the DH domain of Vav3 was essential for ERα activation.</p> <p>Conclusion</p> <p>Vav3 oncogene is overexpressed in human breast cancer. Vav3 complexes with ERα and enhances ERα activity. These findings suggest that Vav3 overexpression may aberrantly enhance ERα-mediated signaling axis and play a role in breast cancer development and/or progression.</p

    The Gammaherpesvirus m2 Protein Manipulates the Fyn/Vav Pathway through a Multidocking Mechanism of Assembly

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    To establish latent infections in B-cells, gammaherpesviruses express proteins in the infected B-cells of the host that spuriously activate signalling pathways located downstream of the B-cell receptor. One such protein is M2, a murine gammaherpesvirus 68-encoded molecule that activates the Vav1/Rac1 pathway via the formation of trimolecular complexes with Scr family members. Previous reports have shown that the formation of this heteromolecular complex involves interactions between a proline rich region of M2 and the Vav1 and Fyn SH3 domains. Here, we show that the optimal association of these proteins requires a second structural motif encompassing two tyrosine residues (Tyr120 and 129). These residues are inducibly phosphorylated by Fyn in non-hematopoietic cells and constitutively phosphorylated in B-cells. We also demonstrate that the phosphorylation of Tyr120 creates specific docking sites for the SH2 domains of both Vav1 and Fyn, a condition sine qua non for the optimal association of these two signalling proteins in vivo. Interestingly, signaling experiments indicate that the expression of M2 in B-cells promotes the tyrosine phosphorylation of Vav1 and additional signaling proteins, a biological process that requires the integrity of both the M2 phosphotyrosine and proline rich region motifs. By infecting mice with viruses mutated in the m2 locus, we show that the integrity of each of these two M2 docking motifs is essential for the early steps of murine gammaherpesvirus-68 latency. Taken together, these results indicate that the M2 phosphotyrosine motif and the previously described M2 proline rich region work in a concerted manner to manipulate the signaling machinery of the host B-cell

    The Minimal Autoinhibited Unit of the Guanine Nucleotide Exchange Factor Intersectin

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    Intersectin-1L is a member of the Dbl homology (DH) domain guanine nucleotide exchange factors (GEF) which control Rho-family GTPase signaling. Intersectin-1L is a GEF that is specific for Cdc42. It plays an important role in endocytosis, and is regulated by several partners including the actin regulator N-WASP. Intact intersectin-1L shows low Cdc42 exchange activity, although the isolated catalytic DH domain shows high activity. This finding suggests that the molecule is autoinhibited. To investigate the mechanism of autoinhibition we have constructed a series of domain deletions. We find that the five SH3 domains of intersectin are important for autoinhibition, with the fifth domain (SH3(E)) being sufficient for the bulk of the autoinhibitory effect. This SH3 domain appears to primarily interact with the DH domain. We have determined the crystal structure of the SH3(E)-DH domain construct, which shows a domain swapped arrangement in which the SH3 from one monomer interacts with the DH domain of the other monomer. Analytical ultracentrifugation and gel filtration, however, show that under biochemical concentrations, the construct is fully monomeric. Thus we propose that the actual autoinhibited structure contains the related intramolecular SH3(E)-DH interaction. We propose a model in which this intramolecular interaction may block or distort the GTPase binding region of the DH domain
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