Effect of Organic Acids on Reactions Catalyzed by Manganese Peroxidase from Phanerochaete chrysosporium

The effect of several organic acids on the oxidation of Mn(II) catalyzed by manganese peroxidase was studied. Reactivities of manganese peroxidase and chemically prepared Mn(III) organic acid complexes towards phenolic compounds were compared. If lactate appears to be the best complexant for manganese peroxidase activity, chemically prepared Mn(III)—lactate complex is a less effective oxidant towards phenolic compounds than other Mn(III)—complexes. Our results agree with the hypothesis that certain organic acids are involved in the catalytic cycle of manganese peroxidase. Malonate and lactate seem to be the most attractive complexants for practical applications of manganese peroxidase and were used in enzymatic treatment of hardwood kraft pulp. Bleaching of kraft pulp was studied and after alkaline extraction, a significant decrease of kappa number was measured. The bleaching was enhanced in lactate buffer.     

Defining the healthy "core microbiome" of oral microbial communities

Background  

Most studies examining the commensal human oral microbiome are focused on disease or are limited in methodology. In order to diagnose and treat diseases at an early and reversible stage an in-depth definition of health is indispensible. The aim of this study therefore was to define the healthy oral microbiome using recent advances in sequencing technology (454 pyrosequencing).     

Cell counting and carbon utilization velocities via microbial calorimetry

Bacteria rapidly metabolize sugars and produce heat accordingly (Escherichia coli, aerobic conditions, 25 degrees C). Two kinds of heat output are gotten: (1) from excess cells and limiting carbon, 2 x 10(9) to 5 x 10(9) cells, 5-50 nanomole glucose; (2) from limited cells and excess carbon, 0. 1 x 10(9)-1 x 10(9) bacteria and 200-600 nmol glucose. The thermograms from heat conduction calorimetry under the first conditions measure velocities of sugar uptake and initial metabolic throughput in 1-6-min time spans before a growth cycle possibly can occur. Under the second conditions with limited cells, power output plateaus to a steady state proportional to cell biomass and number of cells. In order to evaluate the calorimetric means for measuring number of cells, six independent means including spectrophotometry (turbidity) were compared: microkjeldahl nitrogen, biuret protein, dry weight, microscopy direct counting in Petroff-Hausser chambers, and viable colony counting. Using turbidity as a central standard, all methods including calorimetry under the second set of conditions agree within +/-18% of one another. Spectrophotometry is the most rapid method but is seriously interfered with by pigments that absorb and foreign particles that also scatter. Calorimetry requires 10-30 min but measures cell numbers in opaque samples impossible for optical means.     

A New Species of Gall Midge (Diptera: Cecidomyiidae) Infesting Switchgrass in the Northern Great Plains

A new species of gall midge, Chilophaga virgati Gagn?? (Diptera: Cecidomyiidae), collected from tillers of switchgrass at Brookings, South Dakota (44.31134?? N, 96.78374?? W) is described here. Plant morphological symptoms of infestation and frequency of tillers infested are also provided. Full-grown larvae of C. virgati were found inside the sheath of the flag leaf of reproductive tillers of clonally replicated spaced plants of a selected southern upland population of switchgrass during October 2008 and 2009. Infested tillers were shorter and lighter than normal tillers and had panicles that were partially encased in the sheath of the flag leaf due to reduced elongation of the peduncle as a result of the feeding of larvae of C. virgati at the proximal end of the panicle and in the intercalary meristem area of the peduncle. Variation was found among 10 genotypes for percentage of tillers infested by C. virgati, with a range from 7.2% to 21.8%. No difference was found between years for infestation rate (12.7% in 2008 and 14.3% in 2009). The mass of infested tillers was 35% that of normal tillers, and infested tillers produced no appreciable amount of viable seeds. Results of this research revealed that C. virgati had direct negative impacts on biomass and seed production in spaced plant nurseries of switchgrass. C. virgati was also observed in seeded swards of northern upland switchgrass cultivars, but its impact in seeded swards has not yet been determined.     

Mitochondrial heteroplasmy and DNA barcoding in Hawaiian <Emphasis Type="Italic">Hylaeus</Emphasis> (<Emphasis Type="Italic">Nesoprosopis</Emphasis>) bees (Hymenoptera: Colletidae)

Background  

The past several years have seen a flurry of papers seeking to clarify the utility and limits of DNA barcoding, particularly in areas such as species discovery and paralogy due to nuclear pseudogenes. Heteroplasmy, the coexistence of multiple mitochondrial haplotypes in a single organism, has been cited as a potentially serious problem for DNA barcoding but its effect on identification accuracy has not been tested. In addition, few studies of barcoding have tested a large group of closely-related species with a well-established morphological taxonomy. In this study we examine both of these issues, by densely sampling the Hawaiian Hylaeus bee radiation.     

Successful immunotherapy with matrix metalloproteinase-derived peptides in adjuvant arthritis depends on the timing of peptide administration

We have recently found that matrix metalloproteinases (MMPs) are targets for T-cell and B-cell reactivity in experimental arthritis. In the present article, we investigate whether modulation of MMP-specific T-cell responses could influence the course of adjuvant arthritis (AA). Lewis rats were treated nasally with MMP peptides prior to or after AA induction. Administration of the MMP-10 or the MMP-16 peptide prior to AA induction reduced the arthritic symptoms. In contrast, administration of the MMP-10 peptide after AA induction aggravated the arthritic symptoms. The present study shows the possible usefulness of MMP peptides for immunotherapy. However, a clear understanding of proper timing of peptide administration is crucial for the development of such therapies.     

Infestation Rates and Tiller Morphology Effects by the Switchgrass Moth on Six Cultivars of Switchgrass

Switchgrass (Panicum virgatum L.) is a potential biomass crop for native species-based biofuel systems in North America. A recently identified pest of switchgrass, the switchgrass moth, Blastobasis repartella (Dietz) (Lepidoptera: Coleophoridae), feeds in the basal above-ground internodes and below-ground in the proaxis and rhizomes, causing premature tiller and rhizome loss. Our goal was to determine genetic and temporal variation among six upland cultivars for frequency of tiller infestation by larvae of the switchgrass moth in mature stands in the northern Great Plains and if variation in biomass production was associated with variation in frequency of infestation. Data were collected in 2011 and 2012 for tiller density, biomass, frequency of infestation, number of leaves per healthy and infested tiller, and weights of healthy and infested tillers. Differences were found among cultivars for tiller density, biomass yield, and numbers of leaves per healthy and infested tillers. ‘Summer’, ‘Sunburst’, ‘Pathfinder’, and ‘Cave-In-Rock’ were the highest yielding cultivars. Mean frequency of infestation was different between 2011 (6.7 %) and 2012 (9.6 %). Infested tillers had one less collared leaf than healthy tillers. The weights of healthy tillers were ca. 3× those of infested tillers in both years, suggesting an impact on biomass accumulation and economic value. Levels of infestation were similar for all six cultivars, indicating no feeding preference by the switchgrass moth larva among genetically diverse cultivars of switchgrass. Regression of biomass yield on frequency of infestation showed negative linear relationships for ‘Carthage’ and ‘Kentucky 1625’.     

A method to characterize the passive elasticity in contracting muscle bundles

There is concern among researchers whether the passive muscle properties, characterized by purely passive material testing procedures, are an appropriate representation of the actual passive component of the muscle. This aspect is of particular importance in the biomechanical analysis of heart muscle response where it is generally agreed that the so-called parallel elasticity cannot be ignored as is done justifiably in the analysis of skeletal muscle response. In the present article, a method of quantifying the passive elasticity in contracting muscle bundles is presented. The method consists of imposing isometric transients (such as the quick-stretch or quick release) on a muscle bundle during the contraction phase and observing the differences in decayed force levels between a normal twitch and that of a perturbed twitch. The proposed method provides a means of obtaining useful passive properties from contracting muscle bundles and circumvents the difficulty of having to characterize muscle properties from separate experiments on quiescent muscle bundles.     

Design of the Endobronchial Valve for Emphysema Palliation Trial (VENT): a non-surgical method of lung volume reduction

Background

Lung volume reduction surgery is effective at improving lung function, quality of life, and mortality in carefully selected individuals with advanced emphysema. Recently, less invasive bronchoscopic approaches have been designed to utilize these principles while avoiding the associated perioperative risks. The Endobronchial Valve for Emphysema PalliatioN Trial (VENT) posits that occlusion of a single pulmonary lobe through bronchoscopically placed Zephyr^® endobronchial valves will effect significant improvements in lung function and exercise tolerance with an acceptable risk profile in advanced emphysema.

Methods

The trial design posted on Clinical trials.gov, on August 10, 2005 proposed an enrollment of 270 subjects. Inclusion criteria included: diagnosis of emphysema with forced expiratory volume in one second (FEV₁) < 45% of predicted, hyperinflation (total lung capacity measured by body plethysmography > 100%; residual volume > 150% predicted), and heterogeneous emphysema defined using a quantitative chest computed tomography algorithm. Following standardized pulmonary rehabilitation, patients were randomized 2:1 to receive unilateral lobar placement of endobronchial valves plus optimal medical management or optimal medical management alone. The co-primary endpoint was the mean percent change in FEV₁ and six minute walk distance at 180 days. Secondary end-points included mean percent change in St. George's Respiratory Questionnaire score and the mean absolute changes in the maximal work load measured by cycle ergometry, dyspnea (mMRC) score, and total oxygen use per day. Per patient response rates in clinically significant improvement/maintenance of FEV₁ and six minute walk distance and technical success rates of valve placement were recorded. Apriori response predictors based on quantitative CT and lung physiology were defined.

Conclusion

If endobronchial valves improve FEV₁ and health status with an acceptable safety profile in advanced emphysema, they would offer a novel intervention for this progressive and debilitating disease.

Trial Registration

ClinicalTrials.gov: NCT00129584