RETRACTED ARTICLE: Antituberculars which target decaprenylphosphoryl-β-D-ribofuranose 2′-oxidase DprE1: state of art

Multidrug resistance is a major barrier in the battle against tuberculosis and still a leading cause of death worldwide. In order to fight this pathogen, two routes are practicable: vaccination or drug treatment. Vaccination against Mycobacterium tuberculosis with the current vaccine Mycobacterium bovis Bacillus Calmette–Guerin is partially successful, being its efficacy variable. A few new tuberculosis vaccines are now in various phases of clinical trials. The emergence of multidrug-resistant strains of M. tuberculosis gave the impulse to discover new effective antitubercular drugs, a few of which are in clinical development. Here we focus on three different classes of very promising antitubercular drugs recently discovered (benzothiazinones, dinitrobenzamides, and benzoquinoxalines) that share the same cellular target: a subunit of the heteromeric decaprenylphosphoryl-β-d-ribose 2′-epimerase, encoded by the dprE1 (or Rv3790) gene. This enzyme is involved in the biosynthesis of d-arabinose which is crucial for the synthesis of the mycobacterial cell wall and essential for the pathogen’s survival.     

RNase in Lasallia hispanica and Cornicularia normoerica: multiplicity of electromorphs and activity changes during a hydration-dehydration cycle

The presence of RNase activity has been detected in the twosaxicolous lichen species, Lasallia hispanica (Frey) Sancho& Crespo and Cornicularia normoerica (Gunn.) DR. Activitywas localized in the soluble fraction and had an acid optimumpH in both species. When proteins from the soluble fractionof the two lichens were separated by isoelectric focusing, multipleelectromorphs with RNase activity were detected. L. hispanicaRNase was separated into seven bands, characterized by pls 7,6.28, 4.58, 4.45, 4.25, 3.95, and 3.47. In C. normoerica fourbands were detected, with pls of 6.28, 3.98, 3.57, and 3.39.The molecular mass of the main RNase of L. hispanica estimatedby SDS-PAGE was 31.86 kDa, which corresponds to the 33 kDa estimatedfor the undenatured RNase by gel chromatography. Proteins fromC. normoerica were resolved by SDS-PAGE in three bands, withestimated molecular mass of 36.07 kDa, 31.86 kDa and 17.13 kDa.In order to improve the detection of RNase activity, gels wereincubated after the run (electrophoresis or isoelectric focusing)in a RNA solution, instead of including the substrate in thegel. In both species, RNase activity increased during hydrationand decreased during desiccation. This pattern of activity resemblesthat of other enzyme activities in lichens, which decrease inresponse to water deficits, and is different from the responseof other poikilohydrous organisms such as bryophytes. Theseresults are discussed in relation to the mechanisms that lichenshave to withstand dehydration. Key words: Comicularia, Lasallia, lichens, ribonuclease, water stress     

Dopamine Depletion Preferentially Impairs D1 over D2-Receptor Regulation of Striatal In Vivo Acetylcholine Release

The roles of D2 and D1 dopaminergic receptors on the regulation of striatal acetylcholine (ACh) release in vivo were examined for a period of 120 min after acute (2 h) or prolonged (16 h) depletion of brain dopamine (DA) by alpha-methyl-p-tyrosine. The reduction of DA transmission did not affect basal ACh output after 2 h but markedly lowered ACh release by 16 h (50%). Acute alpha-methyl-p-tyrosine pretreatment prevented the reduction of ACh release by the D1 antagonist SCH 23390 and its increase by the D2 antagonist, remoxipride, consistent with a drastic reduction of DA transmission at both DA receptors. However, 16 h after alpha-methyl-p-tyrosine, the effect of remoxipride on ACh release was restored, but SCH 23390 still had no effect, suggesting that the D2 inhibitory tone on ACh release had recovered, whereas the reduction of the D1 facilitatory influence persisted. The D1 facilitatory control of ACh neurotransmission thus appears to be more sensitive than the D2 inhibitory control to a reduction in DA transmission. The new model of DA-ACh interaction resulting from these data casts fresh light on the relationship between changes in DA transmission and extrapyramidal motor function.     

Sister Joseph's nodule in a liver transplant recipient: Case report and mini-review of literature

BACKGROUND: Umbilical metastasis is one of the main characteristic signs of extensive neoplastic disease and is universally referred to as Sister Mary Joseph's nodule. CASE PRESENTATION: A 59-years-old Caucasian female underwent liver transplant for end stage liver disease due to hepatitis C with whole graft from cadaveric donor in 2003. After transplantation the patient developed multiple subcutaneous nodules in the umbilical region and bilateral inguinal lymphadenopathy. The excision biopsy of the umbilical mass showed the features of a poorly differentiated papillary serous cystadenocarcinoma. Computed tomographic scan and transvaginal ultrasonography were unable to demonstrate any primary lesion. Chemotherapy was start and the dosage of the immunosuppressive drugs was reduced. To date the patient is doing well and liver function is normal. CONCLUSIONS: The umbilical metastasis can arise from many sites. In some cases, primary tumor may be not identified; nonetheless chemotherapy must be administrated based on patient's history, anatomical and histological findings.     

Improvement of the fungal biocontrol agent Trichoderma atroviride to enhance both antagonism and induction of plant systemic disease resistance

Biocontrol agents generally do not perform well enough under field conditions to compete with chemical fungicides. We determined whether transgenic strain SJ3-4 of Trichoderma atroviride, which expresses the Aspergillus niger glucose oxidase-encoding gene, goxA, under a homologous chitinase (nag1) promoter had increased capabilities as a fungal biocontrol agent. The transgenic strain differed only slightly from the wild-type in sporulation or the growth rate. goxA expression occurred immediately after contact with the plant pathogen, and the glucose oxidase formed was secreted. SJ3-4 had significantly less N-acetylglucosaminidase and endochitinase activities than its nontransformed parent. Glucose oxidase-containing culture filtrates exhibited threefold-greater inhibition of germination of spores of Botrytis cinerea. The transgenic strain also more quickly overgrew and lysed the plant pathogens Rhizoctonia solani and Pythium ultimum. In planta, SJ3-4 had no detectable improved effect against low inoculum levels of these pathogens. Beans planted in heavily infested soil and treated with conidia of the transgenic Trichoderma strain germinated, but beans treated with wild-type spores did not germinate. SJ3-4 also was more effective in inducing systemic resistance in plants. Beans with SJ3-4 root protection were highly resistant to leaf lesions caused by the foliar pathogen B. cinerea. This work demonstrates that heterologous genes driven by pathogen-inducible promoters can increase the biocontrol and systemic resistance-inducing properties of fungal biocontrol agents, such as Trichoderma spp., and that these microbes can be used as vectors to provide plants with useful molecules (e.g., glucose oxidase) that can increase their resistance to pathogens.     

Rho-mediated cytoskeletal rearrangement in response to LPA is functionally antagonized by Rac1 and PIP2

G-protein-coupled receptors signal through Rho to induce actin cytoskeletal rearrangement. We previously demonstrated that thrombin stimulates Rho-dependent process retraction and rounding of 1321N1 astrocytoma cells. Surprisingly, while lysophosphatidic acid (LPA) activated RhoA in 1321N1 cells, it failed to produce cell rounding. Thrombin, unlike LPA, decreased Rac1 activity, and activated (GTPase-deficient) Rac1 inhibited thrombin-stimulated cell rounding, while expression of dominant-negative Rac1 promoted LPA-induced rounding. LPA and thrombin receptors appear to differ in coupling to Gi, as LPA but not thrombin-stimulated 1321N1 cell proliferation was pertussis toxin-sensitive. Blocking Gi with pertussis toxin enabled LPA to induce cell rounding and to decrease activated Rac1. These data support the hypothesis that Rac1 and Gi activation antagonize cell rounding. Thrombin and LPA receptors also differentially activated Gq pathways as thrombin but not LPA increased InsP3 formation and reduced phosphatidylinositol 4,5-bisphosphate (PIP2) levels. Microinjection of the plekstrin homology domain of phospholipase C (PLC)delta1, which binds PIP2, enabled LPA to elicit cell rounding, consistent with a requirement for PIP2 reduction. We suggest that Rho-mediated cytoskeletal responses are enhanced by concomitant reductions in cellular levels of PIP2 and Rac1 activation and thus effected only by G-protein-coupled receptors with appropriate subsets of G protein activation.