Extended multilocus sequence typing (MLST) analysis of atypical Escherichia isolates was used to identify five novel phylogenetic clades (CI to CV) among isolates from environmental, human, and animal sources. Analysis of individual housekeeping loci showed that E. coli and its sister clade, CI, remain largely indistinguishable and represent nascent evolutionary lineages. Conversely, clades of similar age (CIII and CIV) were found to be phylogenetically distinct. When all Escherichia lineages (named and unnamed) were evaluated, we found evidence that Escherichia fergusonii has evolved at an accelerated rate compared to E. coli, CI, CIII, CIV, and CV, suggesting that this species is younger than estimated by the molecular clock method. Although the five novel clades were phylogenetically distinct, we were unable to identify a discriminating biochemical marker for all but one of them (CIII) with traditional phenotypic profiling. CIII had a statistically different phenotype from E. coli that resulted from the loss of sucrose and sorbitol fermentation and lysine utilization. The lack of phenotypic distinction has likely hindered the ability to differentiate these clades from typical E. coli, and so their ecological significance and importance for applied and clinical microbiology are yet to be determined. However, our sampling suggests that CIII, CIV, and CV represent environmentally adapted Escherichia lineages that may be more abundant outside the host gastrointestinal tract.

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Methods of authenticating already canned fish were developed, using polymerase chain reaction (PCR) followed by sequencing and restriction site analysis. The canning process degrades DNA to fewer than 123 base pairs (bp) in length. Therefore, degenerate PCR primers were designed to amplify short (<123 bp) mitochondrial cytochrome b gene sequences known to differ at specific nucleotides among the species of interest. Sequences of canned tuna (Thunnus albacares, Thuunus alalunga, and Katsuwonus pelamis), bonito (Euthynnus affinis), and frigate mackerel (Auxis thazard) were reproducibly identified, and were used to determine which species or whether more than one species was present in individual cans. Restriction site analysis of two amplified regions of the cytochrome b gene demonstrated a faster and less expensive method than sequencing for distinguishing PCR products of different species. Thus, restriction site analysis of PCR products can be used in conjunction with sequencing to authenticate species in canned fish products. Keywords: Polymerase chain reaction; authentication; fish; tuna; bonito; Thunnus; Katsuwonus; Euthynnus; mitochondrial DNA; cytochrome b gene

Previous studies have shown that 17 beta-estradiol (beta-E2) has a direct acute inhibitory effect on vascular smooth muscle (VSM) contraction. To investigate the mechanisms underlying this phenomenon, we utilized whole cell patch-clamping techniques to study effects of beta-E2 on voltage-dependent Ca2+ channels in cultured VSM cells (VSMC). T- and L-type Ca2+ currents were characterized with ramp and pulse protocols in A7r5 cultured VSMC. T-type current, inactivated in < 100 ms, was reduced by Ba2+ and was comparatively little affected by isradipine. L-type current required higher voltages to activate, inactivated slowly, was greatly increased by Ba2+, and could be completely inhibited by 5 microM isradipine. beta-E2 (10 microM) significantly reduced peak L-type Ba2+ current and T-type Ca2+ current within 1-2 min, whereas alpha E2 (a hormonally inactive isomer of estradiol) caused significantly less reduction in both types of current. Vehicle (0.1% ethanol) had no significant effect on either current. The inhibitory effect of beta-E2 on voltage-dependent Ca2+ currents may contribute to previously demonstrated beta-E2 attenuation of VSM contraction.

We established a pancreatic adenocarcinoma cell line (CFPAC-1) from a patient with cystic fibrosis (CF) and assessed some of its properties. The cells show epithelial morphology and express cytokeratin and oncofetal antigens characteristic of pancreatic duct cells. Basal and stimulated levels of cAMP and cAMP-dependent protein kinase and the biophysical properties of single Cl-channels in CFPAC-1 are similar to those of airway and sweat gland primary cultures and Cl--secreting epithelial cell lines. Anion transport and single Cl-channel activity was stimulated by Ca2+ ionophores but not by forskolin, cAMP analogs, or phosphodiesterase inhibitors. The cells express the CF gene and manifest the most common CF mutation, deletion of three nucleotides resulting in a phenylalanine-508 deletion. These properties have been stable through >80 passages (24 months), suggesting that CFPAC-1 can serve as a continuous cell line that displays the CF defect.