Chemical and biological control of Pythium root rot of tobacco seedlings

There has been a substantial increase in the utilization of float systems to produce tobacco (Nicotiana tabacum) seedlings for transplant by tobacco producers within the last ten years. In Tennessee alone, 80% of transplants were produced in the float system in 1999. Pythium species are some of the most common and destructive root-infecting pathogens of tobacco grown in float culture. They cause damping-off and root rot of seedlings. Pythium spp. infect seedlings by motile spores called zoospores. Characteristic symptoms of Pythium disease are stunting, yellowing and wilting of leaves and severe reduction of the root system. Besides cultural practices, such as sanitation in and around float beds, control options are limited. There are no cultivars that are resistant to Pythium, and until recently, there were no fungicides registered for control of Pythium diseases in the tobacco float bed system. The objectives of this research were to investigate various rates, methods of application, and time of application of the fungicide etridiazole, a rhamnolipid biosurfactant produced by Pseudomonas aeruginosa, and chitosan, a non-toxic oligomer of β-1,4- glucosamine purified from shrimp shells, on Pythium disease of tobacco caused by P. myriotylum. The specific aims were to determine the effect of these products on (i) seed germination, (ii) disease severity, (iii) levels of phytotoxicity to burley tobacco (cv. TN90) seedlings; and (iv) the viability of P. myriotylum after the treatment. Etridiazole applied in float water at 0.075 and 0.150 g l-1 on the same day Pythium was inoculated provided the most effective control of Pythium root rot without compromising plant growth or germination rate. Etridiazole at a rate of 0.56 g l-1 applied as soil drench on the potting soil surface on the same day Pythium was inoculated also provided control, and shoot growth was increased, but root growth was less than etridiazole treatments applied in float water. Incorporation of etridiazole at 0.11, 0.22 and 0.33 g l-1 into growth medium resulted in the lowest seed germination, and phytotoxicity of the seedlings was noted in some replicates in one of two trials. Application of a rhamnolipid biosurfactant at 8 and 12 µ l-1 by soil drench, in float water, and by tray immersion at 2, or 3 wk after seeding, and at inoculaton of Pythium did not provide effective control of Pythium root rot. Chitosan was applied in float water as a solution 24 h before the inoculation of Pythium. Chitosan applied at 400 and 500 µg ml-1 suppressed Pythium root rot in this study. The 500 µg ml-1 treatment resulted in a lower disease rating than the 400 µg ml-1 treatment, however, there were no differences in mean shoot and root weight. Disease rating and plant growth from chitosan at 500 µg ml-1 were comparable to treatment with 0.15 g l-1 etridiazole applied to float water. Unlike the fungicide etridiazole, the mechanism of action of chitosan is primarily induction of plant natural resistance mechanisms

Controlling Accumulation of Fermentation Inhibitors in Biorefinery Recycle Water Using Microbial Fuel Cells

Background Microbial fuel cells (MFC) and microbial electrolysis cells are electrical devices that treat water using microorganisms and convert soluble organic matter into electricity and hydrogen, respectively. Emerging cellulosic biorefineries are expected to use large amounts of water during production of ethanol. Pretreatment of cellulosic biomass results in production of fermentation inhibitors which accumulate in process water and make the water recycle process difficult. Use of MFCs to remove the inhibitory sugar and lignin degradation products from recycle water is investigated in this study. Results Use of an MFC to reduce the levels of furfural, 5-hydroxymethylfurfural, vanillic acid, 4-hydroxybenzaldehyde and 4-hydroxyacetophenone while simultaneously producing electricity is demonstrated here. An integrated MFC design approach was used which resulted in high power densities for the MFC, reaching up to 3700 mW/m2 (356 W/m3 net anode volume) and a coulombic efficiency of 69%. The exoelectrogenic microbial consortium enriched in the anode was characterized using a 16S rRNA clone library method. A unique exoelectrogenic microbial consortium dominated by δ-Proteobacteria (50%), along with β-Proteobacteria (28%), α-Proteobacteria (14%), γ-Proteobacteria (6%) and others was identified. The consortium demonstrated broad substrate specificity, ability to handle high inhibitor concentrations (5 to 20 mM) with near complete removal, while maintaining long-term stability with respect to power production. Conclusion Use of MFCs for removing fermentation inhibitors has implications for: 1) enabling higher ethanol yields at high biomass loading in cellulosic ethanol biorefineries, 2) improved water recycle and 3) electricity production up to 25% of total biorefinery power needs

Improving Enzyme Activity and Broadening Selectivity for Biological Desulfurization and Upgrading of Petroleum Feedstocks

The objective of this project was to develop improved biocatalysts for desulfurization and upgrading of petroleum feedstocks. The goal was to improve the activity and broaden the selectivity of desulfurization enzymes using directed evolution as a tool as well as to explore the impact of ring-opening on biological desulfurizatio

The influence of community factors on the engagement of residents in place promotion: Empirical evidence from an Italian heritage site

The engagement of community residents in place promotion is increasingly recognized as desirable for ensuring effective and reliable communication with tourists. The study investigated the effects of community factors on residents' engagement in the promotion of an Italian heritage site. Community commitment, environmental attitudes, and perceptions of the effectiveness of existing place marketing communications were found to be decisive in influencing residents' engagement in the promotion of the Amalfi Coast. The paper helps to shed light on collaboration in place promotion, thus enriching the debate on the ambassadorship role of residents and suggesting useful insights for policy makers/destination management organization

Towards computional specificity screening of DNA-binding proteins

DNA-binding proteins are key players in the regulation of gene expression and, hence, are essential for cell function. Chimeric proteins composed of DNA-binding domains and DNA modifying domains allow for precise genome manipulation. A key prerequisite is the specific recognition of a particular nucleotide sequence. Here, we quantitatively assess the binding affinity of DNA-binding proteins by molecular dynamics-based alchemical free energy simulations. A computational framework was developed to automatically set up in silico screening assays and estimate free energy differences using two independent procedures, based on equilibrium and non-equlibrium transformation pathways. The influence of simulation times on the accuracy of both procedures is presented. The binding specificity of a zinc-finger transcription factor to several sequences is calculated, and agreement with experimental data is shown. Finally we propose an in silico screening strategy aiming at the derivation of full specificity profiles for DNA-binding proteins

Down-regulation of the caffeic acid \u3cem\u3eO\u3c/em\u3e-methyltransferase gene in switchgrass reveals a novel monolignol analog

Background Down-regulation of the caffeic acid 3-O-methyltransferase EC 2.1.1.68 (COMT) gene in the lignin biosynthetic pathway of switchgrass (Panicum virgatum) resulted in cell walls of transgenic plants releasing more constituent sugars after pretreatment by dilute acid and treatment with glycosyl hydrolases from an added enzyme preparation and from Clostridium thermocellum. Fermentation of both wild-type and transgenic switchgrass after milder hot water pretreatment with no water washing showed that only the transgenic switchgrass inhibited C. thermocellum. Gas chromatography–mass spectrometry (GCMS)-based metabolomics were undertaken on cell wall aqueous extracts to determine the nature of the microbial inhibitors. Results GCMS confirmed the increased concentration of a number of phenolic acids and aldehydes that are known inhibitors of microbial fermentation. Metabolomic analyses of the transgenic biomass additionally revealed the presence of a novel monolignol-like metabolite, identified as trans-3, 4-dimethoxy-5-hydroxycinnamyl alcohol (iso-sinapyl alcohol) in both non-pretreated, as well as hot water pretreated samples. iso-Sinapyl alcohol and its glucoside were subsequently generated by organic synthesis and the identity of natural and synthetic materials were confirmed by mass spectrometric and NMR analyses. The additional novel presence of iso-sinapic acid, iso-sinapyl aldehyde, and iso-syringin suggest the increased activity of a para-methyltransferase, concomitant with the reduced COMT activity, a strict meta-methyltransferase. Quantum chemical calculations were used to predict the most likely homodimeric lignans generated from dehydration reactions, but these products were not evident in plant samples. Conclusions Down-regulation of COMT activity in switchgrass resulted in the accumulation of previously undetected metabolites resembling sinapyl alcohol and its related metabolites, but that are derived from para-methylation of 5-hydroxyconiferyl alcohol, and related precursors and products; the accumulation of which suggests altered metabolism of 5-hydroxyconiferyl alcohol in switchgrass. Given that there was no indication that iso-sinapyl alcohol was integrated in cell walls, it is considered a monolignol analog. Diversion of substrates from sinapyl alcohol to free iso-sinapyl alcohol, its glucoside, and associated upstream lignin pathway changes, including increased phenolic aldehydes and acids, are together associated with more facile cell wall deconstruction, and to the observed inhibitory effect on microbial growth. However, iso-sinapyl alcohol and iso-sinapic acid, added separately to media, were not inhibitory to C. thermocellum cultures

Adherence to Analgesics for Cancer Pain: A Comparative Study of African Americans and Whites Using an Electronic Monitoring Device

Despite well-documented disparities in cancer pain outcomes among African Americans, surprisingly little research exists on adherence to analgesia for cancer pain in this group. We compared analgesic adherence for cancer-related pain over a 3-month period between African Americans and whites using the Medication Event Monitoring System (MEMS). Patients (N = 207) were recruited from outpatient medical oncology clinics of an academic medical center in Philadelphia (≥18 years of age, diagnosed with solid tumors or multiple myeloma, with cancer-related pain, and at least 1 prescription of oral around-the-clock analgesic). African Americans reported significantly greater cancer pain (P \u3c .001), were less likely than whites to have a prescription of long-acting opioids (P \u3c .001), and were more likely to have a negative Pain Management Index (P \u3c .001). There were considerable differences between African Americans and whites in the overall MEMS dose adherence, ie, percentage of the total number of prescribed doses that were taken (53% vs 74%, P \u3c .001). On subanalysis, analgesic adherence rates for African Americans ranged from 34% (for weak opioids) to 63% (for long-acting opioids). Unique predictors of analgesic adherence varied by race; income levels, analgesic side effects, and fear of distracting providers predicted analgesic adherence for African Americans but not for whites. Perspective: Despite evidence of disparities in cancer pain outcomes among African Americans, surprisingly little research exists on African Americans\u27 adherence to analgesia for cancer pain. This prospective study uses objective measures to compare adherence to prescribed pain medications between African American and white patients with cancer pain

The usefulness of arbekacin compared to vancomycin

The bacteriological efficacy response (improved, arbekacin vs. vancomycin; 71.2% vs. 79.5%) and clinical efficacy response (improved, arbekacin vs. vancomycin; 65.3% vs. 76.1%) were not statistically different between the two groups. The complication rate was significantly higher in the vancomycin group (32.9%) compared to the arbekacin group (15.1%) (p = 0.019). Arbekacin was not inferior to vancomycin, and it could be a good alternative drug for vancomycin in methicillin-resistant Staphylococcus aureus (MRSA) treatment

Ethanol and High-Value Terpene Co-Production from Lignocellulosic Biomass of Cymbopogon flexuosus and Cymbopogon martinii

Cymbopogon flexuosus, lemongrass, and C. martinii, palmarosa, are perennial grasses grown to produce essential oils for the fragrance industry. The objectives of this study were (1) to evaluate biomass and oil yields as a function of nitrogen and sulfur fertilization, and (2) to characterize their utility for lignocellulosic ethanol compared to Panicum virgatum (switchgrass). Mean biomass yields were 12.83 Mg lemongrass ha⁻¹ and 15.11 Mg palmarosa ha⁻¹ during the second harvest year resulting in theoretical biofuel yields of 2541 and 2569 L ethanol ha⁻¹ respectively compared to reported 1749–3691 L ethanol ha⁻¹ for switchgrass. Pretreated lemongrass yielded 198 mL ethanol (g biomass)⁻¹ and pretreated palmarosa yielded 170 mL ethanol (g biomass)⁻¹. Additionally, lemongrass yielded 85.7 kg essential oil ha⁻¹ and palmarosa yielded 67.0 kg ha⁻¹ with an estimated value of USD $857 and$1005 ha⁻¹. These data suggest that dual-use crops such as lemongrass and palmarosa may increase the economic viability of lignocellulosic biofuels