Mitochondrial Dysfunction Is Involved in the Toxic Activity of Boric Acid against Saprolegnia

There has been a significant increase in the incidence of Saprolegnia infections over the past decades, especially after the banning of malachite green. Very often these infections are associated with high economic losses in salmonid farms and hatcheries. The use of boric acid to control the disease has been investigated recently both under in vitro and in vivo conditions, however its possible mode of action against fish pathogenic Saprolegnia is not known. In this study, we have explored the transformation in Saprolegnia spores/hyphae after exposure to boric acid (1 g/L) over a period 4–24 h post treatment. Using transmission electron microscopy (TEM), early changes in Saprolegnia spores were detected. Mitochondrial degeneration was the most obvious sign observed following 4 h treatment in about 20% of randomly selected spores. We also investigated the effect of the treatment on nuclear division, mitochondrial activity and function using confocal laser scanning microscopy (CLSM). Fluorescence microscopy was also used to test the effect of treatment on mitochondrial membrane potential and formation of reactive oxygen species. Additionally, the viability and proliferation of treated spores that correlated to mitochondrial enzymatic activity were tested using an MTS assay. All obtained data pointed towards changes in the mitochondrial structure, membrane potential and enzymatic activity following treatment. We have found that boric acid has no effect on the integrity of membranes of Saprolegnia spores at concentrations tested. It is therefore likely that mitochondrial dysfunction is involved in the toxic activity of boric acid against Saprolegnia spp.     

The solution structure of type III effector protein AvrPto reveals conformational and dynamic features important for plant pathogenesis

Pseudomonas syringae pv. tomato, the causative agent of bacterial speck disease of tomato, uses a type III secretion system (TTSS) to deliver effector proteins into the host cell. In resistant plants, the bacterial effector protein AvrPto physically interacts with the host Pto kinase and elicits antibacterial defense responses. In susceptible plants, which lack the Pto kinase, AvrPto acts as a virulence factor to promote bacterial growth. The solution structure of AvrPto reveals a functional core consisting of a three-helix bundle motif flanked by disordered N- and C-terminal tails. Residues required for Pto binding lie in a 19 residue Omega loop. Modeling suggests a hydrophobic patch involving the activation loop of Pto forms a contact surface with the AvrPto Omega loop and that helix packing mediates interactions between AvrPto and putative virulence targets Api2 and Api3. The AvrPto structure has a low stability that may facilitate chaperone-independent secretion by the TTSS.     

A new investigation for some steroidal derivatives as anti-Alzheimer agents

We herein report the anti-Alzheimer activity of some synthesized heterocyclic pyrimidine and thiopyrimidine derivatives fused with steroidal structure. Twenty-one of these compounds were synthesized and conveniently screened for their anti-Alzheimer activities using of Flurbiprofen as the reference drug. Some of these compounds were demonstrated to exhibit remarkable activity and their β-amyloid (Aβ) lowering results as IC(50) values reported.     

Pharmacological activities of some new polycyclic triazolopyrazolopyridazine derivatives

In continuation of our previous work, a novel series of polycyclic derivatives were synthesized and their anti-inflammatory, analgesic and antimicrobial activities were evaluated. Initially the acute toxicity of the compounds was assayed via the determination of their LD(50). Some of the newly compounds exhibited better biological and pharmacological activities than the reference controls with low toxicity (LD(50)). The structure of the new compounds has been established on the bases of chemical and spectroscopic evidences. The detailed synthesis, spectroscopic data, LD(50) and pharmacological activities of the synthesized compounds were reported.     

Neural network assessment of herbal protection against chemotherapeutic-induced reproductive toxicity

The aim of this study is to assess the protective effects of Ginkgo biloba's (GB) extract against chemotherapeutic-induced reproductive toxicity using a data mining tool, namely Neural Network Clustering (NNC) on two types of data: biochemical & fertility indicators and Texture Analysis (TA) parameters. GB extract (1 g/kg/day) was given orally to male albino rats for 26 days. This period began 21 days before a single cisplatin (CIS) intraperitoneal injection (10 mg/kg body weight). GB given orally significantly restored reproductive function. Tested extract also notably reduced the CIS-induced reproductive toxicity, as evidenced by restoring normal morphology of testes. In GB, the attenuation of CIS-induced damage was associated with less apoptotic cell death both in the testicular tissue and in the sperms. CIS-induced alterations of testicular lipid peroxidation were markedly improved by the examined plant extract. NNC has been used for classifying animal groups based on the quantified biochemical & fertility indicators and microscopic image texture parameters extracted by TA. NNC showed the separation of two clusters and the distribution of groups among them in a way that signifies the dose-dependent protective effect of GB. The present study introduces the neural network as a powerful tool to assess both biochemical and histopathological data. We also show here that herbal protection against CIS-induced reproductive toxicity utilizing classic methodologies is validated using neural network analysis.     

Structural analysis of human placental stem and terminal villi from normal and idiopathic growth restricted pregnancies

Studying in detail different histomorphological and pathological findings in placental stem and terminal villi of appropriate for gestational age (AGA) and idiopathic intrauterine growth restricted (IUGR) fetuses, then analyzing their correlation to the neonatal birth weight and to the some morphological features of the placenta. Fifty full-term human placentae of idiopathic IUGR and 25 of AGA pregnancies were processed for haematoxylin and eosin staining and evaluated by light microscope aided with Image Analyzer. The mean number of stem villous arteries, and the mean number of terminal villous capillaries per field are significantly lower in idiopathic IUGR group (4.63 ± 0.46, 47.09 ± 4.44, respectively) than in AGA group (12.36 ± 0.61, 73.35 ± 5.13, respectively) (p = 0.001). Both AGA and idiopathic IUGR placentae share the presence of many pathological features: (1) narrowing of stem villous arteries appears in 38 (76 %) of IUGR cases and in 9 (36 %) of AGA cases with significant difference between groups (p = 0.001); (2) cellular infiltration (villitis) of the stem villi is significantly higher in IUGR cases [24 (48 %)] than in AGA cases [2 (8 %)] (p = 0.001). The study shows significant correlation between the birth weight and different pathologic features in the stem villi as arterial number (r = 0.494; p = 0.000), arterial narrowing (r = 0.283, p = 0.004), degenerative changes (r = 0.331, p = 0.001) and villitis (r = 0.275, p = 0.005). There is also significant correlation between neonatal birth weight and terminal villous capillary number (r = 0.281, p = 0.001) but no significant correlation is found between the birth weight and terminal villous fibrotic changes (r = -0.098, p = 0.318). Histomorphological and pathological changes in the stem villi could explore the cause of idiopathic IUGR. Stem villous arterial number, arterial narrowing, degeneration and villitis could be underlying mechanisms. Further researches on the hormonal and cytokine level should be undertaken to demonstrate the precipitating factors of these changes and the possible preventing measures.     

Expression pattern of tumor necrosis factor alpha in placentae of idiopathic fetal growth restriction

Tumor Necrosis Factor-Alpha (TNF-α) is one of the proinflammatory cytokines that provokes a variety of biological effects on the placenta. The increased placental exposure to TNF-α have induced impaired fetal development in experimental animals, but no data are available on the expression and localization of TNF-α in human placenta of idiopathic fetal growth restriction (FGR). The aim of this study was to characterize the immunohistochemical expression and localization of TNF-α in idiopathic FGR placentae in comparison with those of appropriate for gestational age (AGA) fetuses. 75 human placentae were collected between April, 2010 and March, 2011; 50 placentae were collected from pregnancies associated with idiopathic FGR and 25 placentae from AGA pregnancies. Histological and Immunohistochemical methodologies were employed in formalin fixed paraffin-embedded sections from the placentae of all subjects. Area percent of TNF-α immunostaining was evaluated using image analysis technique. In both AGA and idiopathic FGR placentae, cytoplasmic TNF-α was localized in the decidual and chorionic trophoblasts and in the endothelium of decidual and chorionic vessels. Trophoblast giant cells (TGC) in the decidua and chorionic villi of AGA specimens show deficient or negative TNF-α immunoexpression while those of idiopathic FGR show positive immunostaining. The mean area percent of TNF-α staining was greater in idiopathic FGR placentae (5.93 ± 0.69) compared to AGA ones (3.28 ± 0.41) (p = 0.001). Enhanced placental expression and specific cellular localization and of TNF-α are expected to contribute to impaired fetal development in idiopathic FGR and the TGCs are proposed to be an obvious source of this cytokine in such cases.     

Eukaryotic initiation factor (eIF) 1 carries two distinct eIF5-binding faces important for multifactor assembly and AUG selection

Eukaryotic initiation factor (eIF) 1 is a small protein (12 kDa) governing fidelity in translation initiation. It is recruited to the 40 S subunit in a multifactor complex with Met-tRNA(i)(Met), eIF2, eIF3, and eIF5 and binds near the P-site. eIF1 release in response to start codon recognition is an important signal to produce an 80 S initiation complex. Although the ribosome-binding face of eIF1 was identified, interfaces to other preinitiation complex components and their relevance to eIF1 function have not been determined. Exploiting the solution structure of yeast eIF1, here we locate the binding site for eIF5 in its N-terminal tail and at a basic/hydrophobic surface area termed KH, distinct from the ribosome-binding face. Genetic and biochemical studies indicate that the eIF1 N-terminal tail plays a stimulatory role in cooperative multifactor assembly. A mutation altering the basic part of eIF1-KH is lethal and shows a dominant phenotype indicating relaxed start codon selection. Cheung et al. recently demonstrated that the alteration of hydrophobic residues of eIF1 disrupts a critical link to the preinitiation complex that suppresses eIF1 release before start codon selection (Cheung, Y.-N., Maag, D., Mitchell, S. F., Fekete, C. A., Algire, M. A., Takacs, J. E., Shirokikh, N., Pestova, T., Lorsch, J. R., and Hinnebusch, A. (2007) Genes Dev. 21, 1217-1230 ). Interestingly, eIF1-KH includes the altered hydrophobic residues. Thus, eIF5 is an excellent candidate for the direct partner of eIF1-KH that mediates the critical link. The direct interaction at eIF1-KH also places eIF5 near the decoding site of the 40 S subunit.     

Identification of novel genetic susceptibility loci for Behçet's disease using a genome-wide association study

Introduction

Behçet's disease is a chronic systemic inflammatory disease that remains incompletely understood. Herein, we perform the first genome-wide association study in Behçet's disease.

Methods

Using DNA pooling technology and the Affymetrix 500K arrays, we identified possible candidate gene associations with Behçet's disease in a cohort of 152 Behçet's disease patients and 172 healthy ethnically matched controls. Genetic loci that were identified in the pooling study were genotyped in patients and controls using TaqMan genotyping technology.

Results

We identified genetic associations between Behçet's disease and single-nucleotide polymorphisms (SNPs) in KIAA1529, CPVL, LOC100129342, UBASH3B, and UBAC2 (odds ratio = 2.04, 2.26, 1.84, 1.71, and 1.61, respectively; P value = 4.2 × 10^-5, 1.0 × 10^-4, 3.0 × 10^-4, 1.5 × 10^-3, and 5.8 × 10^-3, respectively). Among the associated SNPs, the Behçet's disease-risk allele in rs2061634 leads to substitution of serine to cysteine at amino acid position 995 (S995C) in the KIAA1529 protein.

Conclusions

Using an unbiased whole-genome genetic association approach, we identified novel candidate genetic loci that are associated with increased susceptibility for Behçet's disease. These findings will help to better understand the pathogenesis of Behçet's disease and identify novel targets for therapeutic intervention.