Chemotaxis of Pseudomonas stutzeri OX1 and Burkholderia cepacia G4 toward chlorinated ethenes

The chemotactic responses of Pseudomonas putida F1, Burkholderia cepacia G4, and Pseudomonas stutzeri OX1 were investigated toward toluene, trichloroethylene (TCE), tetrachloroethylene (PCE), cis-1,2-dichloroethylene (cis-DCE), trans-1,2-dichloroethylene (trans-DCE), 1,1-dichloroethylene (1,1-DCE), and vinyl chloride (VC). P. stutzeri OX1 and P. putida F1 were chemotactic toward toluene, PCE, TCE, all DCEs, and VC. B. cepacia G4 was chemotactic toward toluene, PCE, TCE, cis-DCE, 1,1-DCE, and VC. Chemotaxis of P. stutzeri OX1 grown on o-xylene vapors was much stronger than when grown on o-cresol vapors toward some chlorinated ethenes. Expression of toluene-o-xylene monooxygenase (ToMO) from touABCDEF appears to be required for positive chemotaxis attraction, and the attraction is stronger with the touR (ToMO regulatory) gene.     

Biological effects of extracts obtained from Stryphnodendron adstringens on Herpetomonas samuelpessoai

We report the effect of Stryphnodendron adstringens on the trypanosomatid Herpetomonas samuelpessoai. The parasites were grown at 28 degrees C in a chemically defined medium containing crude extract and fractions at concentrations from 100 to 5000 microg/ml obtained from S. adstringens. Concentrations of 500, 1000, 2500, and 5000 microg/ml both crude extract and semi-purified fraction progressively inhibited the protozoans' growth. At a concentration of 100 microg/ml, crude extract or a semi-purified (F3) fraction did not affect the growth of the protozoans. The F3-9 - F3-12 sub-fractions, at a concentration of 1000 microg/ml, also showed increased inhibitory activity on H. samuelpessoai. The IC50 of the crude extract and the F3 fraction were 538 and 634 microg/ml, respectively. Ultrastructural and enzymatic alterations in the trypanosomatids were also evaluated. H. samuelpessoai cultivated in the presence of IC50 crude extract showed considerable ultrastructural alterations, such as marked mitochondrial swelling with a large number of cristae and evident Golgi complex vesiculation, as observed by transmission electron microscopy. Cells exposed to 538 microg/ml of crude extract at 28 degrees C for 72 h, showed decreased activity of the enzyme succinate cytochrome c reductase, a typical mitochondrion marker, as compared to untreated cells.     

Fingerprinting,embryo type and geographic differentiation in mango (<Emphasis Type="Italic">Mangifera indica</Emphasis> L., Anacardiaceae) with microsatellites

We report the sequence and variability parameters of 16 microsatellite primer pairs obtained from two mango (Mangifera indica L.) genomic libraries after digestion of DNA of the cultivar Tommy Atkins with HaeIII and RsaI and enrichment in CT repeats. Although no significant differences were recorded between the two libraries in the informativeness of the markers obtained, the RsaI library was shown to be more useful than the HaeIII taking into account the efficiency of the library and the feasibility of clone sequencing. The polymorphism revealed by those microsatellites was evaluated in a collection of 28 mango cultivars of different origins. A total of 88 fragments were detected with the 16 simple sequence repeats (SSRs) with an average of 5.5 bands/SSR. Two primer pairs amplified more than a single locus. The mean expected and observed heterozygosities over the 14 single-locus SSRs averaged 0.65 and 0.69 respectively. The total value for the probability of identity was 2.74 × 10⁻⁹. The SSRs studied allowed the unambiguous identification of all the mango genotypes studied and this discrimination can be carried out with just three selected microsatellites. UPGMA cluster analysis and Principal coordinates analysis group the genotypes according to their origin and their classification as monoembryonic or polyembryonic types reflecting the pedigree of the cultivars and the movement of mango germplasm. The results demonstrate the usefulness of microsatellites for studies on identification, variability, germplasm conservation, domestication and movement of germplasm in mango.     

Chiral arylpyrrolidinols: preparation and biological profile

The preparation and biological evaluation of a new class of arylpyrrolidinols is reported. The antinociceptive activity was evaluated in vivo with the hot plate test (HPT) and formalin test (FT), excluding any involvement on motor coordination with the rota-rod test (RRT). The nociceptive behavior in the late phase of FT (representative of chronic pain) suggests an involvement of the antiinflammatory process and it is clearly influenced by the stereochemical features, being the eutomer of phenylpyrrolidinols, the (2R,3S) enantiomer. Despite this, a specific mechanism of action is not yet clarified.     

Ochratoxin A and zearalenone: a comparative study on genotoxic effects and cell death induced in bovine lymphocytes

Ochratoxin A (OTA) and zearalenone (ZEA), two naturally occurring contaminants of animal feed, have been implicated in several mycotoxicoses in farm livestock but there is little information on their genotoxicity and toxicity in these species. Therefore, we investigated on the cytogenetic and cytotoxic effects of both OTA and ZEA in in vitro cultures of bovine lymphocytes. We determined chromosome aberrations (CAs) and sister chromatid exchanges (SCEs) as well as the mitotic index (MI) and cell viability following OTA and ZEA treatment. This report is the first to provide evidence of a statistically significant increase of structural CAs and of SCEs/cell associated with a reduction of the MI in all OTA- and ZEA-treated bovine lymphocyte cultures and a clear reproducible reducing effect of OTA on cell viability mediated by enhanced apoptosis. OTA-induced programmed cell death was not limited to bovine lymphocytes, as comparable data were demonstrated in the human leukemic T-cell line Jurkat.     

Vertebral body innervation: Implications for pain

Vertebral fractures often cause intractable pain. To define the involvement of vertebral body innervation in pain, we collected specimens from male and female patients during percutaneous kyphoplasty, a procedure used for reconstruction of the vertebral body. Specimens were taken from 31 patients (9 men and 22 women) suffering high‐intensity pain before surgery. In total, 1,876 histological preparations were obtained and analysed. Immunohistochemical techniques were used to locate the nerves in the specimens. The nerve fibres were labelled by indirect immunofluorescence with the primary antibody directed against Protein Gene Product 9.5 (PGP 9.5), a pan‐neuronal marker; another primary antibody directed against type IV collagen (Col IV) was used to identify vessels and to determine their relationship with vertebral nerve fibres. The mean percentage of samples in which it was possible to identify nerve fibres was 35% in men and 29% in women. The percentages varied depending on the spinal level considered and the sex of the subject, nerve fibres being mostly present around vessels (95%). In conclusion, there is scarce innervation of the vertebral bodies, with a clear prevalence of fibres located around vessels. It seems unlikely that this pattern of vertebral body innervation is involved in vertebral pain or in pain relief following kyphoplasty. J. Cell. Physiol. 222: 488–491, 2010. © 2009 Wiley‐Liss, Inc.     

Regulation of Response Regulator Autophosphorylation through Interdomain Contacts

DNA-binding response regulators (RRs) of the OmpR/PhoB subfamily alternate between inactive and active conformational states, with the latter having enhanced DNA-binding affinity. Phosphorylation of an aspartate residue in the receiver domain, usually via phosphotransfer from a cognate histidine kinase, stabilizes the active conformation. Many of the available structures of inactive OmpR/PhoB family proteins exhibit extensive interfaces between the N-terminal receiver and C-terminal DNA-binding domains. These interfaces invariably involve the α4-β5-α5 face of the receiver domain, the locus of the largest differences between inactive and active conformations and the surface that mediates dimerization of receiver domains in the active state. Structures of receiver domain dimers of DrrB, DrrD, and MtrA have been determined, and phosphorylation kinetics were analyzed. Analysis of phosphotransfer from small molecule phosphodonors has revealed large differences in autophosphorylation rates among OmpR/PhoB RRs. RRs with substantial domain interfaces exhibit slow rates of phosphorylation. Rates are greatly increased in isolated receiver domain constructs. Such differences are not observed between autophosphorylation rates of full-length and isolated receiver domains of a RR that lacks interdomain interfaces, and they are not observed in histidine kinase-mediated phosphotransfer. These findings suggest that domain interfaces restrict receiver domain conformational dynamics, stabilizing an inactive conformation that is catalytically incompetent for phosphotransfer from small molecule phosphodonors. Inhibition of phosphotransfer by domain interfaces provides an explanation for the observation that some RRs cannot be phosphorylated by small molecule phosphodonors in vitro and provides a potential mechanism for insulating some RRs from small molecule-mediated phosphorylation in vivo.