Basis of selective predation by the aquatic larvae of the salamander, Ambystoma tigrinum

SUMMARY. 1. The effect of several factors on feeding selectivity by three size classes of larvae of Ambystoma tigrinum (Green) was examined. Five types of invertebrate prey were used: Chaoborus, Daphnia , damselflies, Hyalella and water boatmen.
2. Five variables were examined in relation to the electivity indices associated with each prey type: ease of prey consumption, ease of prey capture, relative prey size, prey activity, and microhabitat overlap. No single variable explained the observed electivity.
3. For small larvae (snout-vent length, SVL, <2.5cm) relative prey size was correlated with electivity. For large larvae (SVL >6.5cm), ease of prey consumption, prey activity, and relative prey size predicted electivity values. However, none of the measured variables was related to electivity values found for medium sized larvae (SVL >3.5 and <5.5cm).     

Durability,safety, ease of use and reliability of a type-3 portable monitor and a sheet-style type-4 portable monitor

Sleep and Biological Rhythms - Portable monitors (PMs) are widely used to monitor sleep apnea syndromes. However, the durability, safety, and ease of use of PMs have not been well documented. We...     

A low-cost,high-throughput microfluidic nano-culture platform for functional metagenomics

Functional metagenomics is an attractive culture-independent approach for functional screening of diverse microbiomes to identify known and novel genes. Since functional screening can involve sifting through tens of thousands of metagenomic library clones, an easy high-throughput screening approach is desirable. Here, we demonstrate a proof-of-concept application of a low-cost, high-throughput droplet based microfluidic assay to the selection of antibiotic resistance genes from a soil metagenomic library. Metagenomic library members encapsulated in nanoliter volume water-in-oil droplets were printed on glass slides robotically, and cell growth in individual drops in the presence of ampicillin was imaged and quantified to identify ampicillin-resistant clones. From the hits, true positives were confirmed by sequencing and functional validation. The ease of liquid handling, ease of set-up, low cost, and robust workflow makes the droplet-based nano-culture platform a promising candidate for screening and selection assays for functional metagenomic libraries.     

Primed lymphoid cell tolerance. II. In vivo tolerization of highly tolerogen-sensitive hapten-primed, potentially IgG-producing B cells

The relative ease of tolerizing IgM-bearing versus IgG-bearing B cells was investigated. Previous work had shown that IgG-bearing trinitrophenyl (TNP)-specific B cells from mice primed and boosted with TNP-keyhole limpet hemocyanin (TNP-KLH) are highly susceptible to tolerization in vitro by TNP presented on an unrelated carrier. TNP-OVA was used as tolerogen, as it may represent a more general class of tolerogens than those which are nonmetabolizable or immunoglobulin containing. This study showed that highly primed B cells are tolerizable in vivo using TNP-OVA, with the IgG response to TNP-KLH easier to tolerize than the IgM response. To determine if the ease of tolerization of the IgG response in vivo was due to intrinsic differences in B-cell precursors of the IgM and IgG responses, tolerance was performed in vitro with B cells of defined surface isotypes. A T-independent antigen, TNP-endotoxin, was employed to minimize T-cell effects. At least 10 times as much TNP-OVA was required to tolerize B cells bearing the IgM surface isotype than those with the IgG surface isotype. Thus, the ease of inhibition of the IgG response as compared to the IgM response in vivo by preexposure to TNP-OVA may be at least partially explained by inherent differences in IgM and IgG B-cell precursors.     

Pediatricians’ Own Weight: Self‐perception,Misclassification, and Ease of Counseling

Objectives: Pediatricians underdiagnose overweight and feel ineffective at counseling. Given the relationship between physicians’ health and health habits and counseling behaviors, we sought to determine the 1) percentage of pediatricians who are overweight; 2) accuracy of pediatricians’ own weight status classification; and 3) relationship between weight self‐perception and perceived ease of obesity counseling. Research Methods and Procedures: This study was a cross‐sectional, mail survey of North Carolina pediatricians that queried about their weight status and ease of counseling. Accuracy of pediatricians’ self‐classification of weight status was compared with BMIs derived from self‐reported height and weight. Using logistic regression, controlling for potential confounding variables, we examined the association between weight perception and ease of counseling. Results: The unadjusted response rate was 62%, and the adjusted response rate was 71% (n = 355). Nearly one‐half (49%) of overweight pediatricians did not identify themselves as such. Men had greater adjusted odds of misclassifying overweight than women [odds ratio (OR), 3.61; 95% confidence interval (CI) = 1.81, 7.21]. Self‐classified “thin” pediatricians had nearly six times the odds of reporting more counseling difficulty as a result of their weight than “average” weight pediatricians (OR = 5.69; 95% CI = 2.30, 14.1), and self‐identified “overweight” pediatricians reported nearly four times as great counseling difficulty as “average” weight physicians (OR = 3.84; 95% CI = 1.11, 13.3), after adjustment for self‐reported BMI weight status and other potential confounders. Discussion: The roles that physician weight misclassification and self‐perception potentially play in influencing rates of obesity counseling warrant further research.     

Piriformospora indica, a Cultivable Plant-Growth-Promoting Root Endophyte

Piriformospora indica (Hymenomycetes, Basidiomycota) is a newly described cultivable endophyte that colonizes roots. Inoculation with the fungus and application of fungal culture filtrate promotes plant growth and biomass production. Due to its ease of culture, this fungus provides a model organism for the study of beneficial plant-microbe interactions and a new tool for improving plant production systems.     

Protein utilization by larvae of the black carpet beetle,Attagenus megatoma

An increase in dietary protein for larvae of the black carpet beetle, Attagenus megatoma, resulted in a decreased digestibility that was partly compensated for by substantial increases in both the gross and net efficiency of conversion of digested food into body substance. When the dietary amino acids were in a free form (not protein bound), the rate of food consumption was significantly lower; however, the greater ease of digestion and more efficient utilization of the amino acid diet resulted in a growth rate comparable to that observed on an all-casein diet. Maximum larval weight gain occurred on the stock culture medium, probably due to a combination of a faster rate of food consumption, ease of digestion, and more efficient utilization. Larvae preferentially selected protein from some of the diets, but when no selection was possible, the efficiency of N utilization was inversely proportional to the concentration of N in the diet. The concentrations of faecal uric acid decreased with an increase in dietary protein concentration, especially when expressed as a percentage of the soluble faecal nitrogen.     

Nm 283, an efficient prodrug of the potent anti-HCV agent 2'-C-methylcytidine

In order to improve the oral bioavailability of 2-C-methylcytidine, a potent anti-HCV agent, the corresponding 3'-O-L-valinyl ester derivative (NM 283) has been synthesized Based on its ease of synthesis and its physicochemical properties, NM 283 has emerged as a promising antiviral drug for treatment of chronic HCV infection.     

Recent Bryological Literature, 58

Abstract

Recent field work in Mexico reveals fifteen cleistocarpic moss species in the Neovolcanic Belt, several of which represent new state records for Hidalgo, Michoacán, Puebla or Tlaxcala. The distribution of these species suggests that they have been able to cross the Neovolcanic Belt, but their method of dispersal remains obscure. Local dispersal may be enhanced by forest disturbance, agriculture, grazing and/or by their ability to shed the capsules with ease.     

Prediction of the Ease of Subdivision of Scored Tablets from Their Physical Parameters

At present, the ease of subdivision of scored tablets is estimated in vivo. In order to replace such in vivo testing and to develop a surrogate test which uses in vitro techniques, the association between physical parameters of scored tablets and their ease of subdivision was studied. The physical properties of 23 brands of scored tablets of which their ease of subdivision in vivo was known were established. Statistical modeling using a logistic regression model was used to fit the data and estimate the contribution of each physical parameter to the goodness of the fit. For scored oblong tablets, the critical parameters for their ease of subdivision are: diameter; diameter/width ratio; depth of score line and resistance to crushing. Criteria for each of these parameters were derived. All criteria need to be complied with to guarantee sufficient ease of subdivision of scored oblong tablets. For scored round tablets the critical parameters, in decreasing order of importance, for their ease of subdivision, are: resistance to crushing, diameter, score mark (one- or two-sided), and shape (flat or biconvex). A five-parameter predictive model was developed, showing excellent discrimination. For development, the proposed surrogate tests are sufficiently reliable. For release testing and stability studies, resistance to crushing of a scored tablet is a reliable predictor of its ease of subdivision.     

National evaluation for calving ease,gestation length and birth weight by linear and threshold model methodologies

Data included 393,097 calving ease, 129,520 gestation length, and 412,484 birth weight records on 412,484 Gelbvieh cattle. Additionally, pedigrees were available on 72,123 animals. Included in the models were effects of sex and age of dam, treated as fixed, as well as direct, maternal genetic and permanent environmental effects and effects of contemporary group (herd-year-season), treated as random. In all analyses, birth weight and gestation length were treated as continuous traits. Calving ease (CE) was treated either as a continuous trait in a mixed linear model (LM), or as a categorical trait in linear-threshold models (LTM). Solutions in TM obtained by empirical Bayes (TMEB) and Monte Carlo (TMMC) methodologies were compared with those by LM. Due to the computational cost, only 10,000 samples were obtained for TMMC. For calving ease, correlations between LM and TMEB were 0.86 and 0.78 for direct and maternal genetic effects, respectively. The same correlations but between TMEB and TMMC were 1.00 and 0.98, respectively. The correlations between LM and TMMC were 0.85 and 0.75, respectively. The correlations for the linear traits were above.97 between LM and TMEB but as low as 0.91 between LM and TMMC, suggesting insufficient convergence of TMMC. Computing time required was about 2 hrs, 5 hrs, and 6 days for LM, TMEB and TMMC, respectively, and memory requirements were 169, 171, and 445 megabytes, respectively. Bayesian implementation of threshold model is simple, can be extended to multiple categorical traits, and allows easy calculation of accuracies; however, computing time is prohibitively long for large models.     

Ease of calving, blood chemistry, insulin and bovine growth hormone of newborn calves derived from embryos produced in vitro in culture systems with serum and co-culture or with PVA

Blood chemistry (pH, pCO2, pO2, glucose, lactate) as well as plasma insulin and growth hormone of calves derived from embryos produced under 2 different in vitro culture systems (modified SOFaa with 20% serum and co-culture with bovine oviduct epithelial cells [IVP serum, n=8] or with 3 mg/mL PVA [IVPdefined, n=6]) were compared with those of calves derived from AI (n=5). Calvings were classified according to the ease (unassisted, light traction, heavy traction). Blood samples were taken from the jugular vein of calves at 5, 15, 30 and 60 min, and at 2, 3, 6, 12, 18 and 24 h after delivery, then daily for 6 d. At the second day of life after 4 feedings and a 4-h fasting period, a glucose tolerance test was performed to evaluate glucose metabolism and insulin secretion. Calves in the IVP serum group had higher birth weights than AI calves (LS mean +/- SEM, IVP serum: 45.2 +/- 1.4 kg vs AI: 40.4 +/- 1.7 kg; P < 0.05), while the birth weights of calves in the IVP defined group were in between (IVPdefined: 41.9 +/- 1.6 kg). More IVP serum calves (75%) needed assistance than IVP defined (33%) or AI (40%) calves. The effect of ease of calving vs the effect of embryo culture was compared in relation to blood parameters at birth. There was an effect of ease of calving but not of embryo culture conditions on blood pH, lactate and PCO2. Calves requiring heavy traction had lower pH during the first 3 h after calving, a higher lactate during the first 60 min after calving and a higher pCO2 the first 2 h after calving than calves born unassisted. Calves requiring heavy traction also had lower pH the first 2 h and higher lactate the first 3 h after calving than calves born by light traction. IVP defined calves had lower lactate than IVP serum calves the first 60 min after calving. At 6 h after delivery, all blood parameters had stabilized. There was no effect of either embryo culture or ease of calving on basal insulin and growth hormone level, or the ability of the calves to handle glucose postnatally and during a glucose tolerance test.     

Flow: Statistics, visualization and informatics for flow cytometry

Flow is an open source software application for clinical and experimental researchers to perform exploratory data analysis, clustering and annotation of flow cytometric data. Flow is an extensible system that offers the ease of use commonly found in commercial flow cytometry software packages and the statistical power of academic packages like the R BioConductor project.     

Dose-response effect of a beta3-adrenergic receptor agonist, solabegron, on gastrointestinal transit, bowel function, and somatostatin levels in health

beta(3)-Adrenoceptors(beta(3)-AR) are expressed by cholinergic myenteric neurons and beta(3)-AR agonists are effective in experimental models of diarrhea. Our aim was to explore the effects of a beta(3)-AR agonist, solabegron, on gastrointestinal transit, safety, bowel function, plasma somatostatin, and solabegron pharmacokinetics (PK) following single and multiple doses. In a single-center, double-blind, parallel-group trial, 36 healthy volunteers were randomized to oral solabegron (50 or 200 mg twice daily) or placebo. Transit was measured by a validated method ((99m)Tc-labeled egg meal and (111)In charcoal delivered to the colon via delayed-release capsule). Stool frequency, form, and ease of passage were measured on a validated daily diary; plasma somatostatin by radioimmunoassay and plasma solabegron and its active metabolite by validated liquid chromatography-tandem mass spectroscopy analysis followed by PK analysis using noncompartmental methods. There were no overall or dose-related effects of solabegron on gastric, small bowel, or colonic transit, plasma somatostatin levels, stool frequency, form, or ease of passage in healthy volunteers. Solabegron and active metabolite exposures (area under the curve and maximum serum concentration) at both dose levels were consistent with PK at similar doses in previous phase I studies. We concluded that 7 days of the beta(3)-AR agonist, solabegron, 50 or 200 mg twice daily, did not significantly alter gastrointestinal or colonic transit or bowel function. In this study, medication was generally well tolerated with few adverse events reported and no clinically significant changes in vital signs observed. Further studies on clinical efficacy, visceral sensitivity, and gastrointestinal transit are required in irritable bowel syndrome patients.     

A slicer for polyacrylamide gels of 3-, 6-, and 18-mm diameter.

A new gel sectioning device for polyacrylamide gel electrophoresis (PAGE) utilizing an iris diaphragm type of concentric cutting blade has been recently described (1). Although gel cylinders of 5- or 6-mm diam are most often used, cylinders of other diameters are often utilized for purposes of sample economy or ease of preparation. The versatile single cutting device described here enables sectioning of PAGE cylinders having 3-, 6-, or 18-mm diam; it can be easily adapted to accept gels with diameters less than 18 mm.     

A comparison between SNaPshot, pyrosequencing, and biplex invader SNP genotyping methods: accuracy, cost, and throughput

Three methods of Single Nucleotide Polymorphism (SNP) detection: SNaPshot, Pyrosequencing and Biplex Invader, with two different chemistries were investigated to compare, (1) accuracy, (2) ease of use, (3) throughput capability, and (4) cost. We genotyped 192 human DNA samples across 24 SNPs (minor allele frequencies above 30%), of which seven SNPs were genotyped with all three methods. We show that the Biplex Invader genotyping method was found to be the most accurate and easiest to use with lowest cost, although Pyrosequencing provided similar results at a low cost. With little optimization, the accuracy of the SNaPshot method was also comparable to these two methods with a higher cost, if only singleplex reactions are used.     

Reaction of the antithrombotic and antimetastatic agent, nafazatrom, with oxidizing radicals

Pulse radiolysis and electron spin resonance experiments have been performed on the antithrombotic and antimetastatic agent, nafazatrom. Results show that nafazatrom is an extremely reactive scavenger of free radicals. The rate of its reaction with Br-2 is higher than rates found for biologically important antioxidants, tocopherol and ascorbate. The radical formed by oxidation of nafazatrom is indicated by ESR to have a structure similar to phenoxyl radical. This radical is found to decay at a rate approaching diffusion controlled rates. The ease of oxidation of nafazatrom makes it ideally suited to act as an antioxidant. This property may be an important determinant of its pharmacological activities.     

A crtB homolog essential for photochromogenicity in Mycobacterium marinum: isolation, characterization, and gene disruption via homologous recombination.

A gene essential for light-induced pigment production was isolated from the photochromogen Mycobacterium marinum by heterologous complementation of an M. marinum cosmid library in the nonchromogen Mycobacterium smegmatis. This gene is part of an operon and homologous to the Streptomyces griseus and Myxococcus xanthus crtB genes encoding phytoene synthase. Gene replacement at this locus was achieved via homologous recombination, demonstrating that its expression is essential for photochromogenicity. The ease of targeted gene disruption in this pathogenic Mycobacterium allows for the dissection of the molecular basis of mycobacterial pathogenesis.     

Dyneins, autophagy, aggregation and neurodegeneration

We recently showed that the dynein motor machinery plays a role in the delivery of autophagosome contents to lysosomes, in the process of autophagosome-lysosome fusion. This may explain a number of important previous observations, including why intracellular aggregates form in mice with dynein mutations that have motor neuron-like disease. These studies highlight the importance of dyneins and autophagy in the clearance of aggregate-prone proteins in general, and also in the specific case of Huntington's disease. Since many common neurodegenerative diseases are associated with intracellular aggregate formation but the causative variants are unknown, it may be worth considering the possibility of genetic lesions affecting autophagy as contributing factors in such disorders. The importance of dyneins in autophagosome-lysosome fusion provides new insights for the microtubule dependency of autophagy. In this Addendum, we review our findings in the contexts of autophagy and neurodegeneration and consider some of the questions raised.