A RGG motif protein is involved in Toxoplasma gondii stress-mediated response

The molecular mechanisms controlling gene expression are still poorly understood in apicomplexan parasites. Here, we report the characterization of a homolog of the single strand binding proteins (named TgSsossB) in Toxoplasma gondii. We previously showed that TgSsossB interacts with the TgAlba proteins that are involved in translation regulation. We examined the role of TgSsossB in stress-mediated response, and particularly the role of its arginine–glycine–glycine (RGG) repeats domain. TgSsossB recombinant protein is able to bind to single strand DNA and RNA in a sequence-independent manner, but not to double stranded DNA. We showed that the RGG motif is not involved in this ability to bind to nucleic acid. We produced a mutant tagged strain lacking the RGG motif of TgSsossB using the knock-in strategy. We observed that this strain exhibited a fitness defect compared with the parental parasites. Moreover, the mutant strain produced fewer plaques in stress conditions, a defect that is due to a slow growth phenotype when extracellular parasites are exposed to stress. At the molecular level, we showed that the TgSsossB protein lacking a RGG motif lost its ability to interact with TgAlba2 and an isoform of TgAlba1, indicating that the TgAlba complex is likely non-functional in those parasites. Thus, our findings define the RGG domain of TgSsossB as a protein–protein interaction platform and underline the role of the TgAlba–TgSsossB complex in stress-mediated response.     

Novel missense mutations of TMPRSS3 in two consanguineous Tunisian families with non‐syndromic autosomal recessive deafness

Recently the TMPRSS3 gene, which encodes a transmembrane serine protease, was found to be responsible for two non‐syndromic recessive deafness loci located on human chromosome 21q22.3, DFNB8 and DFNB10. We found evidence for linkage to the DFNB8/10 locus in two unrelated consanguineous Tunisian families segregating congenital autosomal recessive sensorineural deafness. The audiometric tests showed a loss of hearing greater than 70 dB, in all affected individuals of both families. Mutation screening of TMPRSS3 revealed two novel missense mutations, W251C and P404L, altering highly conserved amino acids of the serine protease domain. Both mutations were not found in 200 control Tunisian chromosomes. The detection of naturally‐occurring TMPRSS3 missense mutations in deafness families identifies functionally important amino acids. Comparative protein modeling of the TMPRSS3 protease domain predicted that W251C might lead to a structural rearrangement affecting the active site H257 and that P404L might alter the geometry of the active site loop and therefore affect the serine protease activity. Hum Mutat 18:101–108, 2001. © 2001 Wiley‐Liss, Inc.     

Bioactive compounds from Hypericum humifusum and Hypericum perfoliatum: inhibition potential of polyphenols with acetylcholinesterase and key enzymes linked to type-2 diabetes

Context: Natural products are reported to have a wide spectrum of pharmacological properties such as antimicrobial, anti-inflammatory and anti-cholinesterase. The genus Hypericum (Hypericaceae) is a source of a variety of molecules with different biological activities, notably hypericin and various phenolics.

Objectives: The goals of the present work were the determination of total phenolic and flavonoid content, hypericin and hyperforin concentration as well as the evaluation of biological of Hypericum humifusum L. (Hhu) and Hypericum perfoliatum L. (Hper).

Materials and methods: The various extracts of aerial parts were powdered, and then extracted with methanol. Antibacterial activity was performed according to minimum inhibitory concentration (MIC) and minimum bactericidal (MBC) methods against four Gram-positive bacteria, four Gram-negative bacteria and yeast.

Results: The results revealed that H. humifusum, bear the highest total phenolic and flavonoid content (48–113?mg GAE/g and 8–41?mg RE/g, respectively) as well as hypericin (60–90?mg/g) and hyperforin (8–30?mg/g) concentration. Both species showed significant antioxidant activity as revealed by DPPH, FRAP, ABTS, and metal chelating assays. H. humifusum exhibited a strong acetylcholinesterase (3.86–4.57?mg GALAEs/g), α-glucosidase (0.73–2.55?mmol ACEs/g) and α-amylase (3–8?mmol ACEs/g) inhibitory activity. The extract of H. humifusum exhibited strong antibacterial activity mainly against Staphylococcus epidermidis, Staphylococus aureus, and Enterococcus faecium (MIC values ranging from 200 to 250?μg/mL). The highest antifungal activity was showed for H. perfoliatum extract (MIC value = 250?μg/mL).

Conclusion: The data suggest that H. humifusum could be used as valuable new natural agents with functional properties for pharmacology industries.     

Recombination structure and genetic relatedness among members of the family <Emphasis Type="Italic">Bromoviridae</Emphasis> based on their RNAs 1 and 2 sequence analyses

In determining putative recombination events and their evolution rates in the RNAs 1 and 2 of currently the known members of the family Bromoviridae, a detailed study comprising 107 accessions retrieved from the international databases, has been carried out by using RECCO and RDP v3.31β algorithms. These programs allowed the detection of potential recombination sites in all the five virus genera composing the family Bromoviridae with various degrees of consistency. The RNAs 1 and 2 showed inferred phylogenies fully congruent and clearly delineated five clusters representing the five studied virus genera. In this respect, we proposed to classify the Ilarviruses in three distinct subgroups instead of 10 as mentioned in several reports of the International Committee on Taxonomy of Viruses where its suggestions were based on antigenic differences. Moreover, we confirmed that Alfalfa mosaic virus should be considered as a component of the Ilarvirus genus instead of being the unique representative of Alfamovirus genus. In addition, Pelargonium zonate spot and Olive latent 2 viruses fully deserve their affiliation to the family Bromoviridae.     

Long-term effects of decreased noradrenergic central nervous system innervation on pain behavior and opioid antinociception

Here we examine whether a permanent reduction in the noradrenergic (NA) innervation of the spinal cord leads to a chronic decreased nociceptive threshold. NA denervation of rats was achieved by intrathecal injection of dopamine beta-hydroxylase antibodies conjugated to the toxin saporin. A subset of animals also underwent unilateral L5 spinal nerve ligature to induce sustained neuropathic pain behavior. NA fibers and terminals were lost throughout the spinal cord 2 weeks after toxin application and were still absent 12 months later, indicating that regeneration did not occur. There was also a widespread loss of NA terminals in the cerebral cortex, whereas innervation of the hypothalamus and amygdala were close to normal and NA innervation of the brainstem was moderately reduced. There was extensive loss of NA cells in the locus coeruleus and A5 and A7 cell groups. Dopaminergic and serotoninergic innervation was normal. Intracerebroventricular injection of the toxin resulted in additional NA reduction in the hypothalamus, amygdala, and A1 and A2 cell groups. Long-term removal of NA afferents did not affect nociceptive thresholds. Neuropathic animals showed greater mechanical hyperalgesia in the affected hindpaw only during the first 60 days after toxin. Rats lacking NA spinal afferents were less responsive to the antinociceptive effects of morphine, especially in the neuropathic hindpaw, and did not display opioid-dependent stress analgesia. Finally, in the spinal cord of toxin-treated rats, immunoreactivity for substance P was decreased, whereas that of its receptor (NK1) was increased. These animals exhibited antinociception to a low dose of an NK1 receptor antagonist. Our results suggest that NA contributes only modestly to determining the nociceptive threshold and that its antinociceptive effects are closely linked to opioidergic and tachykinergic neurotransmission.     

Novel missense mutations of TMPRSS3 in two consanguineous Tunisian families with non‐syndromic autosomal recessive deafness

Regarding this article: The corresponding author of this article regrets that the last name of one of the co‐authors was misspelled. Dr. M’hamed GRATI was incorrectly listed as “GRATRI” in the author list. Since it is too late for the publisher to correct this error in the actual journal article, we wish to clarify the matter for the record, for indexing and abstracting purposes.     

Antioxidative/oxidative effects and retarding osteoconductivity of ciprofloxacin-loaded porous polyvinyl alcohol/bioactive glass hybrid

This study investigated the effect of bioglass (melting)-polyvinyl alcohol (BG (M)-PVA) and bioglass (melting)-polyvinyl alcohol-20 %ciprofloxacin (BG(M)-PVA-20Cip) in improving antioxidant activity and regenerating bone capacity. These composites were implanted in femoral condyles of ovariectomized Wistar rats and compared to that of controls groups. After the different period of implantation (15, 30, 60 and 90 days), the treatment of ovariectomized rats with BG(M)-PVA-20Cip showed a significantly higher malondialdehyde concentration when compared to that of BG(M)-PVA group. The superoxide dismutase, glutathione peroxidase and catalase in BG(M)-PVA-20Cip group showed significantly lower activities when compared to those in BG(M)-PVA group. So, BG(M)-PVA is more tolerated by organism than BG(M)-PVA-20Cip. Moreover, the alkaline phosphatase and acid phosphatase activities showed an excellent osteoinductive property of BG (M)-PVA. This property decreased with the presence of ciprofloxacin which is confirmed by histopathological analysis. Several physicochemical techniques showed a rapid reduction in Si and Na in one hand and an accelerator rise in Ca and P ions concentrations in other hand in BG(M)-PVA than in the BG(M)-PVA-20Cip. Therefore, the incorporation of ciprofloxacin in BG(M)-PVA is characterized by a prooxidant effect in oxidant–antioxidant balance at the beginning of treatment and a retard effect of formation of apatitic phase.