Fluorescence in situ hybridization mapping of six loci containing genes involved in the dioxin metabolism of domestic bovids

Six loci containing genes involved in the dioxin metabolism (ARNT, AHR, CYP1A1, CYP1A2, CYP1B1 and AHRR) were assigned, for the first time, to cattle (Bos taurus, 2n = 60, BTA), river buffalo (Bubalus bubalis, 2n = 50, BBU), sheep (Ovis aries, 2n = 54, OAR) and goat (Capra hircus, 2n = 60, CHI) chromosomes by comparative FISH-mapping and R-banding using bovine BAC-clones. The following chromosome locations were found: ARNT to BTA3q21, BBU6q21, OAR1p21 and CHI3q21, AHR to BTA4q15, BBU8q15, OAR4q15 and CHI4q15; CYP1A1 and CYP1A2 to BTA21q17, BBU20q17, OAR18q17 and CHI21q17; CYP1B1 to BTA11q16, BBU12q22, OAR3p16 and CHI11q16, AHRR to BTA20q24, BBU19q24, OAR16q24 and CHI20q24. All loci were mapped at the same homoeologous chromosomes and chromosome bands of the four bovid species. Comparisons with corresponding human locations were also reported.     

Membrane targeting and pore formation by the type III secretion system translocon

The type III secretion system (T3SS) is a complex macromolecular machinery employed by a number of Gram-negative species to initiate infection. Toxins secreted through the system are synthesized in the bacterial cytoplasm and utilize the T3SS to pass through both bacterial membranes and the periplasm, thus being introduced directly into the eukaryotic cytoplasm. A key element of the T3SS of all bacterial pathogens is the translocon, which comprises a pore that is inserted into the membrane of the target cell, allowing toxin injection. Three macromolecular partners associate to form the translocon: two are hydrophobic and one is hydrophilic, and the latter also associates with the T3SS needle. In this review, we discuss recent advances on the biochemical and structural characterization of the proteins involved in translocon formation, as well as their participation in the modification of intracellular signalling pathways upon infection. Models of translocon assembly and regulation are also discussed.     

Loss of negative regulation by Numb over Notch is relevant to human breast carcinogenesis

The biological antagonism between Notch and Numb controls the proliferative/differentiative balance in development and homeostasis. Although altered Notch signaling has been linked to human diseases, including cancer, evidence for a substantial involvement of Notch in human tumors has remained elusive. Here, we show that Numb-mediated control on Notch signaling is lost in approximately 50% of human mammary carcinomas, due to specific Numb ubiquitination and proteasomal degradation. Mechanistically, Numb operates as an oncosuppressor, as its ectopic expression in Numb-negative, but not in Numb-positive, tumor cells inhibits proliferation. Increased Notch signaling is observed in Numb-negative tumors, but reverts to basal levels after enforced expression of Numb. Conversely, Numb silencing increases Notch signaling in normal breast cells and in Numb-positive breast tumors. Finally, growth suppression of Numb-negative, but not Numb-positive, breast tumors can be achieved by pharmacological inhibition of Notch. Thus, the Numb/Notch biological antagonism is relevant to the homeostasis of the normal mammary parenchyma and its subversion contributes to human mammary carcinogenesis.     

Effect of Poor Access to Water and Sanitation As Risk Factors for Soil-Transmitted Helminth Infection: Selectiveness by the Infective Route

BackgroundSoil-transmitted helminth (STH) infections are a public health problem in resource-limited settings worldwide. Chronic STH infection impairs optimum learning and productivity, contributing to the perpetuation of the poverty-disease cycle. Regular massive drug administration (MDA) is the cardinal recommendation for its control; along with water, sanitation and hygiene (WASH) interventions. The impact of joint WASH interventions on STH infections has been reported; studies on the independent effect of WASH components are needed to contribute with the improvement of current recommendations for the control of STH. The aim of this study is to assess the association of lacking access to water and sanitation with STH infections, taking into account the differences in route of infection among species and the availability of adequate water and sanitation at home.ConclusionsLack of safe water and proper sanitation pose a risk of STH infections that is distinct according to the route of entry to the human host used by each of the STH species. Interventions aimed to improve water and sanitation access should be highlighted in the recommendations for the control of STH.     

Silencing survivin gene expression promotes apoptosis of human breast cancer cells through a caspase-independent pathway

Survivin is recognized as an attractive target in cancer therapy because of its selective overexpression in the majority of tumors. Upregulated expression of this protein correlates with increased tumor grade, recurrence risk and decreased cancer patients survival. In this study, we assessed the efficacy of two survivin-specific small interfering RNA (siRNA) constructs to inhibit T47D human breast cancer cell growth. After siRNA transfection, T47D cells showed a significant reduction in proliferation and survival exhibiting clear signs of apoptosis. pSil_1 that targeted exon 1 exhibited a stronger inhibitory effect on cell growth, and increased cell apoptosis compared to pSil_30 that targeted exon 4. Cell apoptosis was found to be mediated by translocation of the mitochondrial apoptosis inducing factor (AIF), while no changes were observed in caspase-3 activation and Bid cleavage. Thus, silencing survivin expression using siRNA strategies represents a suitable therapeutic approach to selectively modulate the survival and growth of human breast cancer cells.     

Antagonistic action of siderophores from Rhodotorula glutinis upon the postharvest pathogen Penicillium expansum

Rhodotorulic acid produced by Rhodotorula glutinis strains improved the biological control of blue rot caused by Penicillium expansum in harvested apples. The production of the siderophore was closely associated with the iron concentration in the medium. Thus, very low additions of the metal reduced the siderophore production considerably. The antagonistic effect of R. glutinis and rhodotorulic acid was studied by using in vitro and in vivo assays. In the in vitro assays, rhodotorulic acid reduced the growth of P. expansum, whereas the chelate (rhodotorulic acid plus iron) did not. Siderophore antagonism was then related to competition for iron. In biocontrol assays on apple wounds, the blue mold was more effectively controlled by the antagonistic agent plus siderophore than by the antagonistic agent alone. The disease incidence (DI: percentage of treated wounds that developed rot) was 34% when apples were protected by R. glutinis alone, whereas it was 6% when the fruits were protected by R. glutinis plus rhodotorulic acid.     

Festuca alpestris R. et S. nelle Prealpi bellunesi

Abstract

Festuca alpestris R. et S. in the Alps near Belluno.—Some populations of Festuca from the F. varia aggr. occurring in the south-eastern Alps near Belluno have been recognized as belonging to F. alpestris R. et S. The relationships between this species and F. calva (Hackel) Richter from the Julian Alps are discussed and the diacritic characters are newly defined.     

The extremo-α-carbonic anhydrase (CA) from Sulfurihydrogenibium azorense,the fastest CA known,is highly activated by amino acids and amines

The α-carbonic anhydrase (CA, EC 4.2.1.1) from the extremophilic bacterium Sulfurihydrogenibium azorense (SazCA) was recently shown to be the fastest CA known. Here we investigated this enzyme for its activation with a series of amino acids and amines. The best SazCA activators were d-Phe, l-DOPA, l- and d-Trp, dopamine and serotonin, which showed activation constants in the range of 3–23 nM. l- and d-His, l-Phe, l-Tyr, 2-pyridyl-methylamine and L-adrenaline were also effective activators (K_As in the range of 62–90 nM), whereas d-Dopa, d-Tyr and several heterocyclic amines showed activity in the micromolar range. The good thermal stability, robustness, very high catalytic activity and propensity to be activated by simple amino acids and amines, make SazCA a very interesting candidate for biomimetic CO₂ capture processes.     

Extracellular release of newly synthesized sphingosine-1-phosphate by cerebellar granule cells and astrocytes

Sphingosine-1-phosphate (S1P) is a potent biomediator that can act as either an intracellular or an intercellular messenger. In the nervous system it exerts a wide range of actions, and specific membrane receptors for it have been identified in various regions. However, the physiological origin of extracellular S1P in the nervous system is largely unknown. We investigated cerebellar granule cells at different stages of differentiation and astrocytes in primary cultures as possible origins of extracellular S1P. Although these cells show marked differences in S1P metabolism, we found that they can all release S1P and express mRNAs for S1P specific receptors. Extracellular S1P derives from the export of newly synthesized intracellular S1P, and not from the action of a released sphingosine kinase. S1P release is rapid, efficient, and can be regulated by exogenous stimuli. Phorbol ester treatment resulted in an increase in sphingosine kinase 1 activity in the membranes, accompanied by a significant increase in extracellular S1P. S1P release in cells from the cerebellum emerges as a regulated mechanism, possibly related to a specific pool of newly synthesized S1P. To our knowledge, this is the first evidence of the extracellular release of S1P by primary cells from the CNS, which supports a role of S1P as autocrine/paracrine physiological messenger in the cerebellum.     

Pathogenicity of bacterial isolates to Cyclocephala signaticollis (Coleoptera: Scarabaeidae)

We describe the isolation and identification of pathogenic bacteria obtained from haemolymph of Cyclocephala signaticollis larvae. Two pathogenic bacteria, a Bacillus thuringiensis and an Arthrobacter sp. caused 90–100% mortality to C. signaticollis in 4 days after hemocoel injection, suggesting they might be useful as biological control agents.