Structural difference at the active site of dibucaine resistant variant of human plasma cholinesterase.

Human plasma cholinesterase from five different genotypes -- E1U E1U, E1U E1A, E1A E1A, E1U E1S, E1A E1S, and E1U E1U C5+ -- was purified 8,000 fold from serum by a two-step procedure involving chromatography on DEAE-cellulose and preparative disc electrophoresis. The esterases were labeled with diisopropyl-1, 3-C14-fluorophosphate (DFP) aminoethylated, and digested by trypsin. The trytic digests were subjected to high voltage electrophoresis, and the radioactive peptides were detected by radioautography. Comparison of the peptides revealed different electrophoretic mobilities of the usual and atypical (dibucaine resistant) plasma cholinesterase peptides. The results are consistent with a structural abnormality of the active center in the variant enzyme. No difference was observed an the esteratic site of the enzyme with C5 component.     

Neuropeptides in the gastrointestinal canal of Necturus maculosus

Summary The presence and distribution of regulatory peptides in nerves and endocrine cells of the stomach, intestine and rectum of a urodele amphibian, the mudpuppy, Necturus maculosus, was studied immunohistochemically in sections or whole-mount preparations of the gut wall. The effect of the occurring peptides on gut motility was studied in isolated strip preparations of circular and longitudinal smooth muscle from different parts of the gut.Bombesin-, neurotensin-, substance P- and VIP-like immunoreactivity was present in abundant nerve fibres in the myenteric plexus of both stomach, intestine and rectum. Single fibres or bundles were present in the circular muscle layer and in a well-developed deep muscular plexus in the intestine and rectum. Immunoreactive nerve cells were found in the myenteric plexus of the stomach, intestine (neurotensin only) and rectum. Gastrin/CCK-like immunoreactivity was observed only in a few fibres in stomach and rectum.Endocrine cells containing bombesin-, met-enkephalin-, gastrin/CCK-, neurotensin-, somatostatin- or substance P- like immunoreactivity were present in the mucosa.The effect of bombesin was an inhibition of the rhythmic activity in circular muscle preparations and in longitudinal muscle from the rectum, while longitudinal muscle from the stomach usually responded with a weak increase in tonus. Neurotensin, like bombesin, was inhibitory on the spontaneous rhythmic activity of circular muscle throughout the gut, while the effect on longitudinal muscle was an increase in tonus. Met-enkephalin and substance P increased the tonus of all types of preparations, and often, in addition, initiated a rhythmic activity superimposed on this maintained tonus. VIP had a general inhibitory effect on the preparations, decreasing tonus and/or abolishing rhythmic activity.It is concluded that bombesin-, neurotensin-, substance P- and VIP-like peptides are present in nerves throughout the urodele gut and may have physiological functions in regulating the motility of the gut. The gastrin/CCK-like peptide present in nerves of the stomach and rectum may affect the function of these parts of the gut. The regulatory peptides present in endocrine cells may, perhaps with the exception of the somatostatin-like peptide, affect the motility humorally.     

Tissue MicroRNAs as Predictors of Outcome in Patients with Metastatic Colorectal Cancer Treated with First Line Capecitabine and Oxaliplatin with or without Bevacizumab

Purpose

We tested the hypothesis that expression of microRNAs (miRNAs) in cancer tissue can predict effectiveness of bevacizumab added to capecitabine and oxaliplatin (CAPEOX) in patients with metastatic colorectal cancer (mCRC).

Experimental Design

Patients with mCRC treated with first line CAPEOX and bevacizumab (CAPEOXBEV): screening (n = 212) and validation (n = 121) cohorts, or CAPEOX alone: control cohort (n = 127), were identified retrospectively and archival primary tumor samples were collected. Expression of 754 miRNAs was analyzed in the screening cohort using polymerase chain reaction (PCR) arrays and expression levels were related to time to disease progression (TTP) and overall survival (OS). Significant miRNAs from the screening study were analyzed in all three cohorts using custom PCR arrays. In situ hybridization (ISH) was done for selected miRNAs.

Results

In the screening study, 26 miRNAs were significantly correlated with outcome in multivariate analyses. Twenty-two miRNAs were selected for further study. Higher miR-664-3p expression and lower miR-455-5p expression were predictive of improved outcome in the CAPEOXBEV cohorts and showed a significant interaction with bevacizumab effectiveness. The effects were strongest for OS. Both miRNAs showed high expression in stromal cells. Higher expression of miR-196b-5p and miR-592 predicted improved outcome regardless of bevacizumab treatment, with similar effect estimates in all three cohorts.

Conclusions

We have identified potentially predictive miRNAs for bevacizumab effectiveness and additional miRNAs that could be related to chemotherapy effectiveness or prognosis in patients with mCRC. Our findings need further validation in large cohorts, preferably from completed randomized trials.     

An affinity-enhanced neutralizing antibody against the membrane-proximal external region of human immunodeficiency virus type 1 gp41 recognizes an epitope between those of 2F5 and 4E10

The membrane-proximal external region (MPER) of human immunodeficiency virus type 1 (HIV-1) gp41 bears the epitopes of two broadly neutralizing antibodies (Abs), 2F5 and 4E10, making it a target for vaccine design. A third Ab, Fab Z13, had previously been mapped to an epitope that overlaps those of 2F5 and 4E10 but only weakly neutralizes a limited set of primary isolates. Here, libraries of Fab Z13 variants displayed on phage were engineered and affinity selected against an MPER peptide and recombinant gp41. A high-affinity variant, designated Z13e1, was isolated and found to be approximately 100-fold improved over the parental Fab not only in binding affinity for the MPER antigens but also in neutralization potency against sensitive HIV-1. Alanine scanning of MPER residues 664 to 680 revealed that N671 and D674 are crucial for peptide recognition as well as for the neutralization of HIV-1 by Z13e1. Ab competition studies and truncation of MPER peptides indicate that Z13e1 binds with high affinity to an epitope between and overlapping with those of 2F5 and 4E10, with the minimal peptide epitope WASLWNWFDITN. Still, Z13e1 remained about an order of magnitude less potent than 4E10 against several isolates of pseudotyped HIV-1. The sum of our molecular analyses with Z13e1 suggests that the segment on the MPER of gp41 between the 2F5 and 4E10 epitopes is exposed on the functional envelope trimer but that access to the specific Z13e1 epitope within this segment is limited. Thus, the ability of MPER-bearing immunogens to elicit potent HIV-1-neutralizing Abs may depend in part on recapitulating the particular constraints that the functional envelope trimer imposes on the segment of the MPER to which Z13e1 binds.     

A longitudinal study to assess the persistence of vancomycin-resistant Enterococcus faecium (VREF) on an intensive broiler farm in the United Kingdom

Seven years after the ban of avoparcin, VREF could still be isolated within sectors of the UK broiler industry. The aim of this study was to assess whether there is a carryover of VREF between consecutive flocks of birds, to conduct a preliminary investigation of possible routes of entry of VREF into broiler houses and to follow the dynamics of VREF shed by growing birds. A series of nine visits were made to two of six houses on a conventional broiler farm. A total of 343 vanA VREF were recovered from environmental (95/843) and faecal (248/416) samples. Significant differences were observed in the carryover of VREF between pre- and postcohort postcleaning and disinfection visits (RR 0.57, P=0.006). Ninety-nine percent of the VREF isolates were resistant to more than five antimicrobials, with 42 isolates (n=49) positive for erm(B) and 32 (n=40) for vat(E). Pulsed field gel electrophoresis (PFGE) typing identified 50 PFGE types within 15 different PFGE clusters of 90% similarity, demonstrating a high level of genetic diversity within VREF populations from epidemiologically related broiler flocks and broiler houses. Further characterization of Tn1546 from different clones showed a low diversity of Tn-types, suggesting horizontal transfer of resistance determinants between different genetic clones. Thus, this study does not only show the persistence of VREF but also of multi-drug resistant lineages of VREF.     

The occrrence of vesicular-arbuscular mycorrhiza in barley and wheat grown in some Danish soils with different fertilizer treatments

Summary Soil samples, roots and shoots were collected from barley crops at three locations which had received different combinations of N and P for 10 years, and from long-term fertilizer experiments on barley in a sandy soil and on barley and wheat in a loamy soil.Soils were analysed for available P by an anion exchange resin procedure, roots were examined for intensity of VAM infection, and shoots wee analysed for N and P.Vesicualr-arbuscular mycorrhizal infection was found at all locations. It was most abundant at the three locations with least soil-P and lightest at the two locations high in soil-P. Within loocations an inverse relation was found between soil-P level and intensity of infection. Infection was also intensity. by increasing N-fertilizer. Spore counts from selected samples correlated well with infection intensity. Shoot-P did not differ significantly between treatments in spite of significant differences in soil-P. This points to the significance of vesicular-arbuscular mycorrhiza: a lower soil-P level accompanied by a higher infection intensity seem to counterbalance each other to a certain extent.     

The major outer membrane protein of Fusobacterium nucleatum (FomA) folds and inserts into lipid bilayers via parallel folding pathways

Membrane protein insertion and folding was studied for the major outer membrane protein of Fusobacterium nucleatum (FomA), which is a voltage-dependent general diffusion porin. The transmembrane domain of FomA forms a beta-barrel that is predicted to consist of 14 beta-strands. Here, unfolded FomA is shown to insert and fold spontaneously and quantitatively into phospholipid bilayers upon dilution of the denaturant urea, which was shown previously only for outer membrane protein A (OmpA) of Escherichia coli. Folding of FomA is demonstrated by circular dichroism and fluorescence spectroscopy, by SDS-polyacrylamide gel electrophoresis, and by single-channel recordings. Refolded FomA had a single-channel conductance of 1.1 nS at 1 M KCl, in agreement with the conductance of FomA isolated from membranes in native form. In contrast to OmpA, which forms a smaller eight-stranded beta-barrel domain, folding kinetics of the larger FomA were slower and provided evidence for parallel folding pathways of FomA into lipid bilayers. Two pathways were observed independent of membrane thickness with two different lipid bilayers, which were either composed of dicapryl phosphatidylcholine or dioleoyl phosphatidylcholine. This is the first observation of parallel membrane insertion and folding pathways of a beta-barrel membrane protein from an unfolded state in urea into lipid bilayers. The kinetics of both folding pathways depended on the chain length of the lipid and on temperature with estimated activation energies of 19 kJ/mol (dicapryl phosphatidylcholine) and 70 kJ/mol (dioleoyl phosphatidylcholine) for the faster pathways.     

Non-cultured adipose-derived CD45- side population cells are enriched for progenitors that give rise to myofibres in vivo

Side population (SP) cells are highly able to exclude the Hoechst 33342 dye through membrane transporters, a feature associated with cell immaturity and therefore proposed as a marker of stem cells. Herein we demonstrate that the adipose tissue derived stromal vascular fraction (SVF) contains a novel population of non-haematopoietic “side population” (SPCD45⁻) cells. Simultaneous qRT-PCR of 64 genes revealed that the freshly isolated SPCD45⁻ was highly enriched for cells expressing genes related to stem cells, the Notch pathway, and early vascular precursors. Notably, the expression of smooth muscle actin, C-met and Cd34 together with Angpt2, Flk1, VE-cadherin, and Cd31 suggested a phenotypic resemblance to pericytes and aorta-derived mesoangioblasts. Recent evidence suggests that cells residing within the vascular niche may participate in regeneration of skeletal muscle and although skeletal muscle repair mainly relies on the satellitecell, several reports have shown that vessel-associated cells may adopt a myogenic phenotype when exposed to a muscle environment. In accordance with these findings, we also observed invitro myogenic specification of SPCD45⁻ cells when cocultured with myoblasts. Furthermore, immediate intramuscular engraftment of non-cultured SPCD45⁻ cells gave rise to myofibres andcells lining blood vessels, whereas the SVF only provided donor derived mononuclear cells. We therefore conclude that the SPCD45⁻ fraction of adipose-derived SVF is enriched for cells expressing vascular associated markers and that the myogenic differentiation potential of these cells does not depend on prior in vitro expansion.     

Assessing Greater Sage-Grouse Selection of Brood-Rearing Habitat Using Remotely-Sensed Imagery: Can Readily Available High-Resolution Imagery Be Used to Identify Brood-Rearing Habitat Across a Broad Landscape?

Greater sage-grouse populations have decreased steadily since European settlement in western North America. Reduced availability of brood-rearing habitat has been identified as a limiting factor for many populations. We used radio-telemetry to acquire locations of sage-grouse broods from 1998 to 2012 in Strawberry Valley, Utah. Using these locations and remotely-sensed NAIP (National Agricultural Imagery Program) imagery, we 1) determined which characteristics of brood-rearing habitat could be used in widely available, high resolution imagery 2) assessed the spatial extent at which sage-grouse selected brood-rearing habitat, and 3) created a predictive habitat model to identify areas of preferred brood-rearing habitat. We used AIC model selection to evaluate support for a list of variables derived from remotely-sensed imagery. We examined the relationship of these explanatory variables at three spatial extents (45, 200, and 795 meter radii). Our top model included 10 variables (percent shrub, percent grass, percent tree, percent paved road, percent riparian, meters of sage/tree edge, meters of riparian/tree edge, distance to tree, distance to transmission lines, and distance to permanent structures). Variables from each spatial extent were represented in our top model with the majority being associated with the larger (795 meter) spatial extent. When applied to our study area, our top model predicted 75% of naïve brood locations suggesting reasonable success using this method and widely available NAIP imagery. We encourage application of our methodology to other sage-grouse populations and species of conservation concern.