Peptide-directed assembly of functional supramolecular polymers for biomedical applications: electroactive molecular tongue-twisters (oligoalanine-oligoaniline-oligoalanine) for electrochemically enhanced drug delivery

We report the preparation and characterization of films of electroactive supramolecular polymers based on non-electroactive oligoalanines and electroactive oligoanilines. Fibroblasts adhered to and proliferated on the films, and the delivery of the clinically relevant anti-inflammatory drug dexamethasone phosphate could be enhanced upon the application of an electrical stimulus

The Ursinus Weekly, May 11, 1972

Travelin\u27 5 talent ready • Campus Chest presents: You can\u27t take it with you • U.C. students offered esoteric subject matter • Warren Robinson named St. Andrews scholar • U.C. receives grant • U.C. graduate presents piano concert • Executives discuss gift solicitation on campus • Editorial: Reflections; Need for a counselor • Focus: Barbara Dando • Fidler on the wax: Humble Pie • Faculty portrait: Dr. Louis DeCatur • Strike • College scholars • Letters to the editor: U.S. government defended; Collegeville\u27s smut store; Apathy habit • Final examination schedule • Spring Parents\u27 Day • Ursinus pounds Penn • U.C. baseball loses to Haverford in top of 9th • The Ersinus Weaklyhttps://digitalcommons.ursinus.edu/weekly/1124/thumbnail.jp

Evolutionary tradeoffs in cellular composition across diverse bacteria

One of the most important classic and contemporary interests in biology is the connection between cellular composition and physiological function. Decades of research have allowed us to understand the detailed relationship between various cellular components and processes for individual species, and have uncovered common functionality across diverse species. However, there still remains the need for frameworks that can mechanistically predict the tradeoffs between cellular functions and elucidate and interpret average trends across species. Here we provide a comprehensive analysis of how cellular composition changes across the diversity of bacteria as connected with physiological function and metabolism, spanning five orders of magnitude in body size. We present an analysis of the trends with cell volume that covers shifts in genomic, protein, cellular envelope, RNA and ribosomal content. We show that trends in protein content are more complex than a simple proportionality with the overall genome size, and that the number of ribosomes is simply explained by cross-species shifts in biosynthesis requirements. Furthermore, we show that the largest and smallest bacteria are limited by physical space requirements. At the lower end of size, cell volume is dominated by DNA and protein content—the requirement for which predicts a lower limit on cell size that is in good agreement with the smallest observed bacteria. At the upper end of bacterial size, we have identified a point at which the number of ribosomes required for biosynthesis exceeds available cell volume. Between these limits we are able to discuss systematic and dramatic shifts in cellular composition. Much of our analysis is connected with the basic energetics of cells where we show that the scaling of metabolic rate is surprisingly superlinear with all cellular components

Disposition of total and unbound prednisolone in renal transplant patients receiving anticonvulsants

AbstractDisposition of total and unbound prednisolone in renal transplant patients receiving anticonvulsants. Kidney transplant patients receiving phenytoin or phenobarbital may have decreased graft survival. These drugs have been shown to enhance the metabolism of glucocorticoids. We determined the disposition of total and unbound prednisolone in six stable kidney transplant patients receiving prednisone for immunosuppression and phenytoin or phenobarbital for a seizure disorder. Six similar patients not on anticonvulsants served as controls. A single intravenous dose of prednisolone was administered, and plasma samples were analyzed for prednisolone using a high-performance liquid chromatographic assay. Equilibrium dialysis was used to determine unbound prednisolone concentrations. Pharmacokinetic analysis showed that the half-life of prednisolone was shorter in the anticonvulsant group compared to the controls, based on both total (2.3 ± 0.4 vs. 3.4 ± 0.2hr (SD), P < 0.01) and unbound (1.7 ± 0.3 vs. 2.4 ± 0.2 hr, P < 0.01) concentrations. Total drug clearance was 10.4 ± 2.8 liters/hr (0.171 ± 0.087 liters/hr · kg) in the anticonvulsant group versus 7.2 ± 1.2 liters/hr (0.100 ± 0.014 liters/hr · kg) in the controls (P < 0.05). Unbound prednisolone clearance was 57.2 ± 12.1 versus 46.4 ± 8.7 liters/hr (P > 0.05) and for weight-corrected estimates 0.886 ± 0.224 liters/hr · kg versus 0.644 ± 0.115 liters/hr · kg (P < 0.05) in the two groups, respectively. Thus, the disposition of prednisolone is altered by anticonvulsants in kidney transplant patients and may require dose alteration.Disparition de la prednisolone totale et libre chez des transplantés rénaux recevant des anticonvulsivants. Les transplantés rénaux recevant de la phénytoïne ou du phénobarbital pourraient avoir une survie du greffon diminuée. Ces médicaments se sont avérés capables de stimuler le métabolisme des glucocorticoïdes. Nous avons déterminé l'élimination de la prednisolone totale et libre chez six transplantés rénaux stables recevant de la prédnisone pour leur immunosuppression et de la phénytoïne ou du phénobarbital pour une épilepsie. Six malades identiques sans anticonvulsivants ont servi de contrôle. Une dose unique intraveineuse de prednisolone a été administrée, et des échantillons plasmatiques ont été analysés pour la prednisolone en utilisant un dosage par chromatographie liquide à haute pression. Une dialyse à l'équilibre a été utilisée pour déterminer les concentrations de prednisolone non liée. L'analyse pharmacocinétique a montré que la demi-vie de la prednisolone était plus courte dans le groupe aux anticonvulsivants par rapport aux contrôles, qu'il s'agisse des concentrations totales (2,3 ± 0,4 contre 3,4 ± 0,2hr (SD), P < 0,01) ou libres (1,7 ± 0,3 contre 2,4 ± 0,2 hr, P < 0,01). La clearance totale du médicament était de 10,4 ± 2,8 litres/hr (0,171 ± 0,087 litres/hr · kg) dans le groupe anticonvulsivant contre 7,2 ± 1,2 litres/hr (0,100 ± 0,014 litres/hr· kg) chez les contrôles (P < 0,05). La clearance de la prednisolone non liée était de 57,2 ±12,1 contre 46,4 ± 8,7 litres/hr (P > 0,05), et après correction pour le poids de 0,886 ± 0,224 litres/hr · kg contre 0,644 ± 0,115 litres/hr · kg (P < 0,05) dans les deux groupes, respectivement. Ainsi, l'élimination de la prednisolone est altérée par les anticonvulsivants chez les transplantés rénaux et peut imposer des modifications de la dose

A Unique Signal Distorts the Perception of Species Richness and Composition in High-Throughput Sequencing Surveys of Microbial Communities: a Case Study of Fungi in Indoor Dust

Sequence-based surveys of microorganisms in varied environments have found extremely diverse assemblages. A standard practice in current high-throughput sequence (HTS) approaches in microbial ecology is to sequence the composition of many environmental samples at once by pooling amplicon libraries at a common concentration before processing on one run of a sequencing platform. Biomass of the target taxa, however, is not typically determined prior to HTS, and here, we show that when abundances of the samples differ to a large degree, this standard practice can lead to a perceived bias in community richness and composition. Fungal signal in settled dust of five university teaching laboratory classrooms, one of which was used for a mycology course, was surveyed. The fungal richness and composition in the dust of the nonmycology classrooms were remarkably similar to each other, while the mycology classroom was dominated by abundantly sporulating specimen fungi, particularly puffballs, and appeared to have a lower overall richness based on rarefaction curves and richness estimators. The fungal biomass was three to five times higher in the mycology classroom than the other classrooms, indicating that fungi added to the mycology classroom swamped the background fungi present in indoor air. Thus, the high abundance of a few taxa can skew the perception of richness and composition when samples are sequenced to an even depth. Next, we used in silico manipulations of the observed data to confirm that a unique signature can be identified with HTS approaches when the source is abundant, whether or not the taxon identity is distinct. Lastly, aerobiology of indoor fungi is discussed. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00248-013-0266-4) contains supplementary material, which is available to authorized users

Evolutionary tradeoffs in cellular composition across diverse bacteria

One of the most important classic and contemporary interests in biology is the connection between cellular composition and physiological function. Decades of research have allowed us to understand the detailed relationship between various cellular components and processes for individual species, and have uncovered common functionality across diverse species. However, there still remains the need for frameworks that can mechanistically predict the tradeoffs between cellular functions and elucidate and interpret average trends across species. Here we provide a comprehensive analysis of how cellular composition changes across the diversity of bacteria as connected with physiological function and metabolism, spanning five orders of magnitude in body size. We present an analysis of the trends with cell volume that covers shifts in genomic, protein, cellular envelope, RNA and ribosomal content. We show that trends in protein content are more complex than a simple proportionality with the overall genome size, and that the number of ribosomes is simply explained by cross-species shifts in biosynthesis requirements. Furthermore, we show that the largest and smallest bacteria are limited by physical space requirements. At the lower end of size, cell volume is dominated by DNA and protein content—the requirement for which predicts a lower limit on cell size that is in good agreement with the smallest observed bacteria. At the upper end of bacterial size, we have identified a point at which the number of ribosomes required for biosynthesis exceeds available cell volume. Between these limits we are able to discuss systematic and dramatic shifts in cellular composition. Much of our analysis is connected with the basic energetics of cells where we show that the scaling of metabolic rate is surprisingly superlinear with all cellular components

Temperature Adaptation at Homologous Sites in Proteins from Nine Thermophile–Mesophile Species Pairs

Whether particular amino acids are favored by selection at high temperatures over others has long been an open question in protein evolution. One way to approach this question is to compare homologous sites in proteins from one thermophile and a closely related mesophile; asymmetrical substitution patterns have been taken as evidence for selection favoring certain amino acids over others. However, most pairs of prokaryotic species that differ in optimum temperature also differ in genome-wide GC content, and amino acid content is known to be associated with GC content. Here, I compare homologous sites in nine thermophilic prokaryotes and their mesophilic relatives, all with complete published genome sequences. After adjusting for the effects of differing GC content with logistic regression, 139 of the 190 pairs of amino acids show significant substitutional asymmetry, evidence of widespread adaptive amino acid substitution. The patterns are fairly consistent across the nine pairs of species (after taking the effects of differing GC content into account), suggesting that much of the asymmetry results from adaptation to temperature. Some amino acids in some species pairs deviate from the overall pattern in ways indicating that adaptation to other environmental or physiological differences between the species may also play a role. The property that is best correlated with the patterns of substitutional asymmetry is transfer free energy, a measure of hydrophobicity, with more hydrophobic amino acids favored at higher temperatures. The correlation of asymmetry and hydrophobicity is fairly weak, suggesting that other properties may also be important

Factors That Affect Large Subunit Ribosomal DNA Amplicon Sequencing Studies of Fungal Communities: Classification Method, Primer Choice, and Error

Nuclear large subunit ribosomal DNA is widely used in fungal phylogenetics and to an increasing extent also amplicon-based environmental sequencing. The relatively short reads produced by next-generation sequencing, however, makes primer choice and sequence error important variables for obtaining accurate taxonomic classifications. In this simulation study we tested the performance of three classification methods: 1) a similarity-based method (BLAST + Metagenomic Analyzer, MEGAN); 2) a composition-based method (Ribosomal Database Project naïve Bayesian classifier, NBC); and, 3) a phylogeny-based method (Statistical Assignment Package, SAP). We also tested the effects of sequence length, primer choice, and sequence error on classification accuracy and perceived community composition. Using a leave-one-out cross validation approach, results for classifications to the genus rank were as follows: BLAST + MEGAN had the lowest error rate and was particularly robust to sequence error; SAP accuracy was highest when long LSU query sequences were classified; and, NBC runs significantly faster than the other tested methods. All methods performed poorly with the shortest 50–100 bp sequences. Increasing simulated sequence error reduced classification accuracy. Community shifts were detected due to sequence error and primer selection even though there was no change in the underlying community composition. Short read datasets from individual primers, as well as pooled datasets, appear to only approximate the true community composition. We hope this work informs investigators of some of the factors that affect the quality and interpretation of their environmental gene surveys