Comparative analysis of the complete sequence of the plastid genome of Parthenium argentatum and identification of DNA barcodes to differentiate Parthenium species and lines

<p>Abstract</p> <p>Background</p> <p><it>Parthenium argentatum </it>(guayule) is an industrial crop that produces latex, which was recently commercialized as a source of latex rubber safe for people with Type I latex allergy. The complete plastid genome of <it>P. argentatum </it>was sequenced. The sequence provides important information useful for genetic engineering strategies. Comparison to the sequences of plastid genomes from three other members of the Asteraceae, <it>Lactuca sativa, Guitozia abyssinica </it>and <it>Helianthus annuus </it>revealed details of the evolution of the four genomes. Chloroplast-specific DNA barcodes were developed for identification of <it>Parthenium </it>species and lines.</p> <p>Results</p> <p>The complete plastid genome of <it>P. argentatum </it>is 152,803 bp. Based on the overall comparison of individual protein coding genes with those in <it>L. sativa, G. abyssinica </it>and <it>H. annuus</it>, we demonstrate that the <it>P. argentatum </it>chloroplast genome sequence is most closely related to that of <it>H. annuus</it>. Similar to chloroplast genomes in <it>G. abyssinica, L. sativa </it>and <it>H. annuus</it>, the plastid genome of <it>P. argentatum </it>has a large 23 kb inversion with a smaller 3.4 kb inversion, within the large inversion. Using the <it>mat</it>K and <it>psb</it>A-<it>trn</it>H spacer chloroplast DNA barcodes, three of the four <it>Parthenium </it>species tested, <it>P. tomentosum</it>, <it>P. hysterophorus </it>and P. <it>schottii</it>, can be differentiated from <it>P. argentatum</it>. In addition, we identified lines within <it>P. argentatum</it>.</p> <p>Conclusion</p> <p>The genome sequence of the <it>P. argentatum </it>chloroplast will enrich the sequence resources of plastid genomes in commercial crops. The availability of the complete plastid genome sequence may facilitate transformation efficiency by using the precise sequence of endogenous flanking sequences and regulatory elements in chloroplast transformation vectors. The DNA barcoding study forms the foundation for genetic identification of commercially significant lines of <it>P</it>. <it>argentatum </it>that are important for producing latex.</p

A Summary of the Slush Hydrogen Technology Program for the National Aero-Space Plane

Slush hydrogen, a mixture of solid and liquid hydrogen, offers advantages of higher density (16 percent) and higher heat capacity (18 percent) than normal boiling point hydrogen. The combination of increased density and heat capacity of slush hydrogen provided a potential to decrease the gross takeoff weight of the National Aero-Space Plane (NASP) and therefore slush hydrogen was selected as the propellant. However, no large-scale data was available on the production, transfer and tank pressure control characteristics required to use slush hydrogen as a fuel. Extensive testing has been performed at the NASA Lewis Research Center K-Site and Small Scale Hydrogen Test Facility between 1990 and the present to provide a database for the use of slush hydrogen. This paper summarizes the results of this testing

Downregulation of a CYP74 Rubber Particle Protein Increases Natural Rubber Production in \u3ci\u3eParthenium argentatum\u3c/i\u3e

We report functional genomics studies of a CYP74 rubber particle protein from Parthenium argentatum, commonly called guayule. Previously identified as an allene oxide synthase (AOS), this CYP74 constitutes the most abundant protein found in guayule rubber particles. Transgenic guayule lines with AOS gene expression down-regulated by RNAi (AOSi) exhibited strong phenotypes that included agricultural traits conducive to enhancing rubber yield. AOSi lines had higher leaf and stem biomass, thicker stembark tissues, increased stem branching and improved net photosynthetic rate. Importantly, the rubber content was significantly increased in AOSi lines compared to the wild-type (WT), vector control and AOS overexpressing (AOSoe) lines, when grown in controlled environments both in tissue-culture media and in greenhouse/growth chambers. Rubber particles from AOSi plants consistently had less AOS particle-associated protein, and lower activity (for conversion of 13-HPOT to allene oxide). Yet plants with downregulated AOS showed higher rubber transferase enzyme activity. The increase in biomass in AOSi lines was associated with not only increases in the rate of photosynthesis and non-photochemical quenching (NPQ), in the cold, but also in the content of the phytohormone SA, along with a decrease in JA, GAs, and ABA. The increase in biosynthetic activity and rubber content could further result from the negative regulation of AOS expression by high levels of salicylic acid in AOSi lines and when introduced exogenously. It is apparent that AOS in guayule plays a pivotal role in rubber production and plant growth

Yoga as a Means to Reduce Anxiety in Adolescents: A Pilot Study

Long QT Syndrome (LQTS) is a genetic condition affecting 1:2,500 that predisposes individuals to cardiac arrhythmias (Ellis et al., 2009). Life threatening symptoms are often unpredictable although there are known triggers to LQTS specific cardiac events. Triggers include physical exertion, emotional upset, and sleep. Events could be triggered by medications, dehydration, and other circumstances that affect cardiac rhythm. Treatments include betablockers, pacemakers, internal cardioverter defibrillators, and automated external defibrillator as precautionary measures. As such, LQTS patients often present to their emergency room (ER) when they become symptomatic. Research suggests that LQTS patients’ experience dissatisfaction in the ER and treatment is a concern (Felgoise et al., 2012). Cardiac training in emergency medicine specialties is limited. Given that ER physician training in cardiology is general, rarer cardiac arrhythmias such as LQTS are unknown by many ER physicians. Studies of ER patient satisfaction have shown that quality of communication and interactions between ER physician and patient, understanding of care, and wait times are related to patient satisfaction in pediatric and adult populations (Margaret et al., 2002). This study aims to learn why LQTS patients are dissatisfied by assessing doctor-patient relationship variables, patient satisfaction, patients’ perception of physicians’ knowledge, and problem-solving skills. The goal is to identify how to increase patients’ ability to be better consumers of ER care, use problem-solving strategies and advocate for appropriate treatment with regard to LQTS-related needs. This study fuses multidisciplinary perspectives for enhancement of patient satisfaction. This is a prospective cross-sectional study of pediatric and adult patients with LQTS and parent perceptions of ER care. A convenience sample of LQTS patients or their parent will complete an online survey. 150 participants will be recruited via announcements on websites focused on cardiac arrhythmias. Measures include Working Alliance Inventory, Personal Information Questionnaire, a standardized ER patient satisfaction questionnaire, and the Social Problem-Solving Inventory. Pearson product moment correlations and multiple regression analyses will be conducted to determine the relationship among the variables. Subscales of the WAI, average estimated wait times, problem-solving skills, and ratings of knowledge and communication from the and ER satisfaction questionnaire will be input as predictor variables and global patient satisfaction will be the criterion variable. Results will lead to understanding ER experiences that may be advantaged by introducing CBT strategies to promote better consumerism of services by LQTS patients. Data will provide physicians with an understanding of LQTS patients’ perceptions of ER care. Findings will determine what predicts satisfaction and whether patients have realistic expectations for ER care. Problem-solving skills training have been effective for helping other medical patients navigate the healthcare system (Nezu et al., 1998), and may be appropriate for LQTS patients. Results will provide guidance for cardiologists and psychologists to best prepare LQTS patients for ER experiences

Transcriptome and gene expression analysis in cold-acclimated guayule (\u3ci\u3eParthenium argentatum\u3c/i\u3e) rubber-producing tissue

Natural rubber biosynthesis in guayule (Parthenium argentatum Gray) is associated with moderately cold night temperatures. To begin to dissect the molecular events triggered by cold temperatures that govern rubber synthesis induction in guayule, the transcriptome of bark tissue, where rubber is produced, was investigated. A total of 11,748 quality expressed sequence tags (ESTs) were obtained. The vast majority of ESTs encoded proteins that are similar to stress-related proteins, whereas those encoding rubber biosynthesis- related proteins comprised just over one percent of the ESTs. Sequence information derived from the ESTs was used to design primers for quantitative analysis of the expression of genes that encode selected enzymes and proteins with potential impact on rubber biosynthesis in field-grown guayule plants, including 3-hydroxy-3-methylglutaryl-CoA synthase, 3-hydroxy-3-methylglutaryl-CoA reductase, farnesyl pyrophosphate synthase, squalene synthase, small rubber particle protein, allene oxide synthase, and cis-prenyl transferase. Gene expression was studied for field-grown plants during the normal course of seasonal variation in temperature (monthly average maximum 41.7 °C to minimum 0 °C, from November 2005 through March 2007) and rubber transferase enzymatic activity was also evaluated. Levels of gene expression did not correlate with air temperatures nor with rubber transferase activity. Interestingly, a sudden increase in night temperature 10 days before harvest took place in advance of the highest CPT gene expression level