Aeromonas tecta sp. nov., isolated from clinical and environmental sources

Five Aeromonas strains, isolated from both clinical and environmental sources and characterized by a polyphasic approach, including phylogenetic analysis derived from gyrB, rpoD, and 16S rRNA gene sequencing, as well as DNA-DNA hybridization, extensive biochemical and antibiotic susceptibility tests, were recognized as members of an unknown, or undescribed, Aeromonas species. These "Aeromonas eucrenophila-like" strains were closely related to the species A. eucrenophila and Aeromonas encheleia, but they were negative for indole and acid from glycerol tests. Therefore, based on the results of the phylogenetic analyses and DNA-DNA pairing data of these strains, a novel species of the genus Aeromonas is described, for which the name Aeromonas tecta is proposed with isolate F518(T) (CECT7082(T), DSM17300(T), MDC91(T)) as the type strain.     

Synthesis and structure-activity relationships for biphenyl H3 receptor antagonists with moderate anti-cholinesterase activity

The combination of antagonism at histamine H(3) receptors and inhibition of acetylcholinesterase has been recently proposed as an approach to devise putative new therapeutic agents for cognitive diseases. The 4,4'-biphenyl fragment has been reported by us as a rigid scaffold leading to potent and selective non-imidazole H(3)-antagonists. Starting from these premises, the current work presents an expanded series of histamine H(3) receptor antagonists, characterized by a central 4,4'-biphenyl scaffold, where the structure-activity profile of both mono-basic and di-basic compounds is further explored and their ability to inhibit rat brain cholinesterase activity is determined. The steric properties and basicity of the terminal groups were modulated in symmetrical compounds, carrying identical substituents, and in asymmetrical compounds, having a piperidine ring at one end and different groups at the other. The length of the linker connecting the biphenyl scaffold to the terminal groups was also modulated. Binding studies at rat and human H(3) receptors evidenced the highest binding affinities for di-basic compounds, in the order of nM concentrations, and that the steric requirements for the two terminal groups are different. Many potent compounds showed good selectivity profiles over the other histamine receptors. Interestingly, some derivatives displayed a moderate ability to inhibit rat brain cholinesterase, for example compound 12 (1-[2-(4'-piperidinomethyl-biphenyl-4-yl)ethyl]piperidine) has a pIC(50)=5.96 for cholinesterase inhibition and high H(3) receptor binding affinity and antagonist potency (pK(i)=8.70; pK(B)=9.28). These compounds can be considered as rigid analogs of a recently reported class of dual-acting compounds and as a promising starting point for the design of new H(3)-antagonists with anti-cholinesterase activity.     

Three-step biological process for the treatment of the liquid fraction of cattle manure

The liquid fraction of cattle manure was subjected to a biological treatment combining anoxic-anaerobic and oxic processes in order to stabilize the organic matter and reduce nitrogen and phosphorus so as to avoid problems of pollution when applying it to the land. The anoxic process was carried out at 30 degrees C in a CSTR reactor, the anaerobic process in a UASB reactor at 37 degrees C and the oxic treatment in another CSTR at 20 degrees C. The following results were obtained when working under optimum conditions (removal efficiencies in brackets): COD was reduced from 42 to 3.8 g/L (>90%); total solids from 41 to 14 (67%); total volatile solids from 22 to 7.0 (68%); total Kjeldahl nitrogen from 2.2 to 0.1 g/L (95%); NH4(-)-N from 1.10 to 0.02 g/L (98%) and Total-Phosphorus from 0.696 to 0.058 g/L (92%). Nitrates, undetected in the liquid fraction of cattle manure, were present in the final effluent as a result of nitrification. To reduce the amount of nitrates, different recirculation rates were tested. The minimum nitrate concentration achieved was 127 mg/L using a recirculation ratio of 4.     

Regulation of steroidogenesis by atrial natriuretic peptide (ANP) in the rat testis: differential involvement of GC-A and C receptors

Previous studies have established a stimulatory effect of natriuretic peptides (NP) on testosterone production in mouse Leydig cells as intense as that of LH. Chronic administration of ANP in mice, on the other side, reduced testosterone levels. So, the understanding of the role of ANP on testicular steroidogenesis has been impaired by discrepant findings. The aim of the present study was to clarify the physiological role of ANP in the rat testis steroidogenesis using a model that preserves the interactions between testis cells and a medium devoid of any circulating factors that could interfere with testosterone production. First, ANP was immunolocalized in the interstitial compartment of the rat testis, mainly in Leydig cells. We also determined the presence of ANP and both GC-A (guanylyl cyclase A) and C receptors by real-time PCR in testis. Perfusion in vitro of testis with ANP (1 and 3x10(-7)M) stimulated testosterone production in a time- and dose-dependent manner. On the other side, testosterone secretion induced by LH was blunted by ANP. Similar effect was obtained using the specific C receptor ligand, cANF, indicating the involvement of C receptor in such response. In conclusion, ANP stimulated testosterone production in the rat testis perfused in vitro but decreased testosterone production LH-induced, effect that seems to involve C receptor. To this extent, our results suggest the existence of a local and complex peptidergic system in the rat testis, involving ANP and its receptors that could importantly modulate the androgen biosynthesis.     

Enantiodiscrimination of bilirubin-IXalpha enantiomers in biomembrane models: has chirality a role in bilirubin toxicity?

Simple biomembrane models, namely micellar aggregates formed by enantiopure sodium N-acylprolinates, are able to convert the racemic mixture of bilirubin-IXα into an enantiomerically enriched mixture, thus suggesting a possible role of chirality in bilirubin toxicity due to the perturbation of neuron membrane dynamics. The length of alkyl chain does not influence the extent of equilibrium displacement, however, it affects the conformation of bilirubin, thus confirming the role of lipid structure in the membrane/bilirubin interaction, and suggesting a non-superficial main site of association.     

Src homology 2-containing inositol 5-phosphatase 1 binds to the multifunctional docking site of c-Met and potentiates hepatocyte growth factor-induced branching tubulogenesis

Hepatocyte growth factor (HGF)/scatter factor is a multifunctional cytokine that induces mitogenesis, motility, and morphogenesis in epithelial, endothelial, and neuronal cells. The receptor for HGF/scatter factor was identified as c-Met tyrosine kinase, and activation of the receptor induces multiple signaling cascades. To gain further insight into c-Met-mediated multiple events at a molecular level, we isolated several signaling molecules including a novel binding partner of c-Met, SH2 domain-containing inositol 5-phosphatase 1 (SHIP-1). Western blot analysis revealed that SHIP-1 is expressed in the epithelial cell line, Madin-Darby canine kidney (MDCK) cells. SHIP-1 binds at phosphotyrosine 1356 at the multifunctional docking site. Because a number of signaling molecules such as Grb2, phosphatidylinositol 3-kinase, and Gab1 bind to the multifunctional docking site, we further performed an in vitro competition study using glutathione S-transferase- or His-tagged signaling molecules with c-Met tyrosine kinase. Our binding study revealed that SHIP-1, Grb2, and Gab1 bound preferentially over phosphatidylinositol 3-kinase. Surprisingly, MDCK cells that overexpress SHIP-1 demonstrated branching tubulogenesis within 2 days after HGF treatment, whereas wild-type MDCK cells showed tubulogenesis only after 6 days following treatment without altering cell scattering or cell growth potency. Furthermore, overexpression of a mutant SHIP-1 lacking catalytic activity impaired HGF-mediated branching tubulogenesis.     

Atypical glandular cells of undetermined significance. Cytologic predictive value for glandular involvement in high grade squamous intraepithelial lesions

OBJECTIVE: To verify the cytologic predictive value of a diagnosis of atypical glandular cells of undetermined significance (AGUS) in high grade squamous intraepithelial lesions (HSIL) cases. STUDY DESIGN: In a retrospective study, 98 cases of HSIL were reviewed. All patients were referred for colposcopy and directed biopsy to confirm the cytologic diagnoses. Loop excision of the transformation zone was performed to treat clinical lesions. Sensitivity, specificity, positive and negative predictive value were evaluated. Kappa statistics and logistic regression analysis were used to evaluate the findings statistically. RESULTS: By logistic regression analysis, we found that the chance of finding squamous intraepithelial lesions involving glands in AGUS smears was 5.32 times higher than in those with no AGUS. It was 5.74 times higher in cervical intraepithelial neoplasia (CIN) 3 lesions than in CIN 2. CONCLUSION: The cytologic predictive value for HSIL involving glands is statistically significant when specific and objective criteria are used for the AGUS diagnosis.     

STING Contacts: a web-based application for identification and analysis of amino acid contacts within protein structure and across protein interfaces

Amino acid contacts in terms of atomic interactions are essential factors to be considered in the analysis of the structure of a protein and its complexes. Consequently, molecular biologists do require specific tools for the identification and visualization of all such contacts. Graphical contacts (GC) and interface forming residue graphical contacts (IFRgc) presented here, calculate atomic contacts among amino acids based on a table of predefined pairs of the atom types and their distances, and then display them using number of different forms. The inventory of currently listed contact types by GC and IFRgc include hydrogen bonds (in nine different flavors), hydrophobic interactions, charge-charge interactions, aromatic stacking and disulfide bonds. Such extensive catalog of the interactions, representing the forces that govern protein folding, stability and binding, is the key feature of these two applications. GC and IFRgc are part of STING Millennium Suite. AVAILABILITY: http://sms.cbi.cnptia.embrapa.br/SMS, http://trantor.bioc.columbia.edu/SMS, http://mirrors.rcsb.org//SMS, http://www.es.embnet.org/SMS and http://www.ar.embnet.org/SMS (Options: Graphical Contacts and IFR Graphical Contacts).