Spontaneous ecchymoses.

The patient's lifestyle was undoubtedly to blame for the appearance of her skin. The loss of her beloved pet may have been a tipping point.

Numerous large nodules on scalp.

The patient told us that his father had "cysts" on his body, too. This familial connection provided a clue to the diagnosis.

Isolation and Characterization of Bacterial Cellulase Producers for Biomass Deconstruction: A Microbiology Laboratory Course.

The conversion of biomass to biofuels presents a solution to one of the largest global challenges of our era, climate change. A critical part of this pipeline is the process of breaking down cellulosic sugars from plant matter to be used by microbes containing biosynthetic pathways that produce biofuels or bioproducts. In this inquiry-based course, students complete a research project that isolates cellulase-producing bacteria from samples collected from the environment. After obtaining isolates, the students characterize the production of cellulases. Students then amplify and sequence the 16S rRNA genes of confirmed cellulase producers and use bioinformatic methods to identify the bacterial isolates. Throughout the course, students learn about the process of generating biofuels and bioproducts through the deconstruction of cellulosic biomass to form monosaccharides from the biopolymers in plant matter. The program relies heavily on active learning and enables students to connect microbiology with issues of sustainability. In addition, it provides exposure to basic microbiology, molecular biology, and biotechnology laboratory techniques and concepts. The described activity was initially developed for the Introductory College Level Experience in Microbiology (iCLEM) program, a research-based immersive laboratory course at the US Department of Energy Joint BioEnergy Institute. Originally designed as an accelerated program for high-potential, low-income, high school students (11th-12th grade), this curriculum could also be implemented for undergraduate coursework in a research-intensive laboratory course at a two- or four-year college or university.

Engineering Bacteria to Catabolize the Carbonaceous Component of Sarin: Teaching E. coli to Eat Isopropanol.

We report an engineered strain of Escherichia coli that catabolizes the carbonaceous component of the extremely toxic chemical warfare agent sarin. Enzymatic decomposition of sarin generates isopropanol waste that, with this engineered strain, is then transformed into acetyl-CoA by enzymatic conversion with a key reaction performed by the acetone carboxylase complex (ACX). We engineered the heterologous expression of the ACX complex from Xanthobacter autotrophicus PY2 to match the naturally occurring subunit stoichiometry and purified the recombinant complex from E. coli for biochemical analysis. Incorporating this ACX complex and enzymes from diverse organisms, we introduced an isopropanol degradation pathway in E. coli, optimized induction conditions, and decoupled enzyme expression to probe pathway bottlenecks. Our engineered E. coli consumed 65% of isopropanol compared to no-cell controls and was able to grow on isopropanol as a sole carbon source. In the process, reconstitution of this large ACX complex (370 kDa) in a system naïve to its structural and mechanistic requirements allowed us to study this otherwise cryptic enzyme in more detail than would have been possible in the less genetically tractable native Xanthobacter system.

A Case of Psoriasis Replaced by Allergic Contact Dermatitis in a 12-Year-Old Boy.

Allergic contact dermatitis is a significant clinical problem in children and one that the use of essential oils and natural remedies probably exacerbates. We report a case of chronic plaque psoriasis replaced by allergic contact dermatitis in a 12-year-old boy. We suspect that the immunologic response to a hapten in lavender oil disrupted the pathogenesis of psoriasis, causing the psoriasis to temporarily "disappear."

Genetic and biochemical investigations of the role of MamP in redox control of iron biomineralization in Magnetospirillum magneticum.

Magnetotactic bacteria have evolved complex subcellular machinery to construct linear chains of magnetite nanocrystals that allow the host cell to sense direction. Each mixed-valent iron nanoparticle is mineralized from soluble iron within a membrane-encapsulated vesicle termed the magnetosome, which serves as a specialized compartment that regulates the iron, redox, and pH environment of the growing mineral. To dissect the biological components that control this process, we have carried out a genetic and biochemical study of proteins proposed to function in iron mineralization. In this study, we show that the redox sites of c-type cytochromes of the Magnetospirillum magneticum AMB-1 magnetosome island, MamP and MamT, are essential to their physiological function and that ablation of one or both heme motifs leads to loss of function, suggesting that their ability to carry out redox chemistry in vivo is important. We also develop a method to heterologously express fully heme-loaded MamP from AMB-1 for in vitro biochemical studies, which show that its Fe(III)-Fe(II) redox couple is set at an unusual potential (-89 ± 11 mV) compared with other related cytochromes involved in iron reduction or oxidation. Despite its low reduction potential, it remains competent to oxidize Fe(II) to Fe(III) and mineralize iron to produce mixed-valent iron oxides. Finally, in vitro mineralization experiments suggest that Mms mineral-templating peptides from AMB-1 can modulate the iron redox chemistry of MamP.

Exploring bacterial lignin degradation.

Plant biomass represents a renewable carbon feedstock that could potentially be used to replace a significant level of petroleum-derived chemicals. One major challenge in its utilization is that the majority of this carbon is trapped in the recalcitrant structural polymers of the plant cell wall. Deconstruction of lignin is a key step in the processing of biomass to useful monomers but remains challenging. Microbial systems can provide molecular information on lignin depolymerization as they have evolved to break lignin down using metalloenzyme-dependent radical pathways. Both fungi and bacteria have been observed to metabolize lignin; however, their differential reactivity with this substrate indicates that they may utilize different chemical strategies for its breakdown. This review will discuss recent advances in studying bacterial lignin degradation as an approach to exploring greater diversity in the environment.

Identification and characterization of a multifunctional dye peroxidase from a lignin-reactive bacterium.

Plant biomass represents a renewable feedstock that has not yet been fully tapped because of the difficulty in accessing the carbon in its structural biopolymers. Lignin is an especially challenging substrate, but select microbes have evolved complex systems of enzymes for its breakdown through a radical-mediated oxidation process. Fungal systems are well-characterized for their ability to depolymerize lignin, but the ability of bacteria to react with this substrate remains elusive. We have therefore focused on elucidating strategies used by lignin-reactive soil bacteria and describing their oxidative enzyme systems. We now report the identification and characterization of an unusual C-type dye-decolorizing peroxidase from Amycolatopsis sp. 75iv2 (DyP2), which belongs to a family of heme peroxidases reported to be involved in bacterial lignin degradation. Biochemical studies indicate that DyP2 has novel function for this family, with versatile and high activity both as a peroxidase and Mn peroxidase (k(cat)/K(M) ≈ 10(5)-10(6) M(-1) s(-1)). It also has a Mn-dependent oxidase mode of action that expands its substrate scope. Crystallographic studies of DyP2 at 2.25 Å resolution show the existence of a Mn binding pocket and support its key role in catalysis.

Discovery and characterization of heme enzymes from unsequenced bacteria: application to microbial lignin degradation.

Bacteria and other living organisms offer a potentially unlimited resource for the discovery of new chemical catalysts, but many interesting reaction phenotypes observed at the whole organism level remain difficult to elucidate down to the molecular level. A key challenge in the discovery process is the identification of discrete molecular players involved in complex biological transformations because multiple cryptic genetic components often work in concert to elicit an overall chemical phenotype. We now report a rapid pipeline for the discovery of new enzymes of interest from unsequenced bacterial hosts based on laboratory-scale methods for the de novo assembly of bacterial genome sequences using short reads. We have applied this approach to the biomass-degrading soil bacterium Amycolatopsis sp. 75iv2 ATCC 39116 (formerly Streptomyces setonii and S. griseus 75vi2) to discover and biochemically characterize two new heme proteins comprising the most abundant members of the extracellular oxidative system under lignin-reactive growth conditions.

Growth of wildtype and mutant E. coli strains in minimal media for optimal production of nucleic acids for preparing labeled nucleotides.

Since RNAs lie at the center of most cellular processes, there is a need for synthesizing large amounts of RNAs made from stable isotope-labeled nucleotides to advance the study of their structure and dynamics by nuclear magnetic resonance (NMR) spectroscopy. A particularly effective means of obtaining labeled nucleotides is to harvest these nucleotides from bacteria grown in defined minimal media supplemented with 15NH4Cl and various carbon sources. Given the high cost of carbon precursors required for labeling nucleic acids for NMR studies, it becomes important to evaluate the optimal growth for commonly used strains under standard minimal media conditions. Such information is lacking. In this study, we characterize the growth for Escherichia coli strains K12, K10zwf, and DL323 in three minimal media with isotopic-labeled carbon sources of acetate, glycerol, and glycerol combined with formate. Of the three media, the LeMaster-Richards and the Studier media outperform the commonly used M9 media and both support optimal growth of E. coli for the production of nucleotides. However, the growth of all three E. coli strains in acetate is reduced almost twofold compared to growth in glycerol. Analysis of the metabolic pathway and previous gene array studies help to explain this differential growth in glycerol and acetate. These studies should benefit efforts to make selective 13C-15N isotopic-labeled nucleotides for synthesizing biologically important RNAs.

Hospital provision of uncompensated care and public program enrollment.

Hospital provision of uncompensated care is partly a function of insurance coverage of state populations. As states expand insurance coverage options and reduce the number of uninsured, hospital provision of uncompensated care should also decrease. Controlling for hospital characteristics and market factors, the authors estimate that increases in MinnesotaCare (a state-subsidized health insurance program for the working poor) enrollment resulted in a 5-year cumulative savings of $58.6 million in hospital uncompensated care costs. Efforts to evaluate access expansions should take into account the costs of the program and the savings associated with reductions in hospital uncompensated care.