842 research outputs found

    Comparison of the effects of kanamycin and geneticin on regeneration of papaya from root tissue

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    Kanamycin and geneticin are commonly used for the selection of neomycin phosphotransferase II (npt II) transformed plants. Since papaya tissue is sensitive to both antibiotics, it is difficult to explore their effects on the regeneration process solely based on using non-transformed tissues. Adventitious roots derived from npt II-transgenic and non-transgenic papaya shoots in vitro were used as explants in this investigation. The effects of kanamycin and geneticin on callus formation, embryogenesis, and conversion of somatic embryos to shoots were compared. Callus growth derived from npt II-transformed root explants was apparently enhanced on kanmycin within 50-200 mg l(-1) or on geneticin within 12.5-50 mg l(-1) as compared to those on antibiotic-free controls. The percentages of npt II-transformed somatic embryo-forming callus were not significantly different (16.3-18.3%) on geneticin less than 6.25 mg l(-1) and only slightly reduced (11.2-15.7%) on geneticin within 12.5-50 mg l(-1), whereas, formation of somatic embryos was strongly suppressed on kanamycin media. Conversion rates of npt II-transformed somatic embryos to shoots were not significantly different among all kanamycin or geneticin treatments. Percentages of the callus derived from non-transformed root explants were greatly reduced on the medium containing more than 25 mg l(-1) kanamycin or geneticin, and no somatic embryos formed from untransformed callus on any kanamycin or geneticin media. Our results indicated that somatic embryogenesis of callus derived from npt II-transformed root explants of papaya was strongly inhibited by kanamycin. Thus, to regenerate npt II-transformed cells from papaya root tissue, we recommend using the lower concentration geneticin (12.5-25 mg l(-1)) to avoid the adverse effects of kanamycin on embryogenesis

    Enhancement of in vitro growth of papaya multishoots by aeration

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    Efficient micropropagation of papaya (Carica papaya L.) has become crucial for multiplication of specific sex types of papaya or transgenic lines resistant to virus infection. In this study, aeration at different intervals with a 0.02 mu m filter disc in the closure of culture flasks ensured exchange of gas components. The effect of aeration on development of multibuds to multishoots was investigated. Multibuds grown, in culture flasks after one-week without aeration followed by a two-week aeration treatment caused a 41% increase in the number of shoots greater than or equal to 0.5 cm, 42% increase in leaf expansion, and 17% increase in leaf numbers in comparison with unaerated materials. Ethylene and oxygen concentrations in the culture flasks were measured by gas chromatography and oxygen electrode at weekly intervals during the culture period. Oxygen concentrations were slightly different between aerated and unaerated culture flasks. Ethylene in the unaerated flask reached the highest level (0.11 ppm) 2 weeks after the treatment, while accumulation of ethylene in the aerated flasks was not detected. The multishoots grown for 3 weeks without aeration showed growth retardation on leaves and epinasty on petioles

    Efficient rooting for establishment of papaya plantlets by micropropagation

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    A low cost micropropagation protocol to produce high quality root systems which are easy and economical to acclimatize is essential for large-scale micropropagation of papaya (Carica papaya L.). In this study, individual shoots (> 0.5 cm) with 2 similar to 3 leaves from in vitro papaya multiple shoots were cultured on MS agar medium containing 2.5 mu M IBA under dark conditions for 1 week for root induction. They were then transferred to agar or vermiculite media, containing half strength MS medium, under aerated or non-aerated conditions, for root development. Rooting percentage of shoots cultured for 2 weeks in aerated vermiculite was 94.5%, compared with 90.0% in non-aerated vermiculite, 71.1% in aerated agar, and 62.2% in non-aerated agar. Shoots with roots were acclimated in vermiculite under 100% RH for 1 week and then under ambient conditions for 2 weeks in a temperature-controlled growth chamber (28 degrees C). The survival rates of the plantlets were 94.5% from aerated vermiculite, 87.8% from non-aerated vermiculite, 42.2% from aerated agar, and 35.6% from non-aerated agar. Thus, root induction in low-concentration IBA agar medium followed by root development in vermiculite containing half strength MS medium under aerated conditions results in efficient rooting of in vitro papaya shoots

    Asymptomatic Pulmonary Hypertension in Systemic Lupus Erythematosus

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    Introduction Pulmonary arterial hypertension (PAH) is a serious and often fatal complication of systemic lupus erythematosus (SLE). Because the diagnosis of PAH often is made years after symptom onset, early diagnostic strategies are essential. Doppler echocardiography currently is considered the noninvasive screening test of choice for evaluating pulmonary hypertension. Aim Screening for asymptomatic pulmonary hypertension in systemic lupus erythematosus patients using Doppler echocardiography, and correlating it with inflammatory parameters of the disease. Patients and Methods Doppler echocardiography was performed in 74 patients with systemic lupus erythematosus over one year (66 adult and 8 juvenile), adult SLE included 57 patients with adult-onset and 9 patients with childhood-onset. Pulmonary hypertension was diagnosed if the peak systolic pressure gradient at the tricuspid valve was more than 30 mmHg. All patients were subjected to full history taking, rheumatological examination, laboratory studies and chest x-ray. Results In seventy four SLE patients, the pulmonary hypertension was detected in 8 patients (10.8%), 7 adult-onset SLE patients (aged from 19 to 30 years) and 1 juvenile SLE (aged 12 years). The range of pulmonary artery systolic pressure was 34–61.2 mmHg (43.19 ± 9.28). No significant differences between patients with and those without pulmonary hypertension as regard clinical features. Significantly higher frequencies of rheumatoid factor and anti-cardiolipin antibodies were found in patients with pulmonary hypertension versus those without ( P = 0.02, P = 0.008 respectively). Positive rheumatoid factor and ACL were significantly associated with occurrence of PAH in SLE ( P = 0.007, P = 0.006 respectively). No significant correlations were found between pulmonary artery pressure, disease duration, SLE Disease Activity Index (SLEDAI), ESR, and anti-ds DNA. Conclusion Patients with SLE have an increased risk of pulmonary arterial hypertension. Echocardiography should be used as a screening tool in patients at high risk for development of pulmonary hypertension. Positive anti-cardiolipin antibodies and rheumatoid factor were significant predictors of pulmonary hypertension in our study

    Andreev Reflection in Ferromagnet/Superconductor/Ferromagnet Double Junction Systems

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    We present a theory of Andreev reflection in a ferromagnet/superconductor/ferromagnet double junction system. The spin polarized quasiparticles penetrate to the superconductor in the range of penetration depth from the interface by the Andreev reflection. When the thickness of the superconductor is comparable to or smaller than the penetration depth, the spin polarized quasiparticles pass through the superconductor and therefore the electric current depends on the relative orientation of magnetizations of the ferromagnets. The dependences of the magnetoresistance on the thickness of the superconductor, temperature, the exchange field of the ferromagnets and the height of the interfacial barriers are analyzed. Our theory explains recent experimental results well.Comment: 8 pages, 9 figures, submitted to Phys. Rev.

    Standardized Outcome Measurement for Patients With Coronary Artery Disease: Consensus From the International Consortium for Health Outcomes Measurement (ICHOM)

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    Coronary artery disease (CAD) outcomes consistently improve when they are routinely measured and provided back to physicians and hospitals. The International Consortium for Health Outcomes Measurement (ICHOM) established a Working Group to define a standard set of outcome measures and risk factors of CAD care. Members were drawn from 4 continents and 6 countries. Using a modified Delphi method, the Group defined who should be tracked, what should be measured, and when such measurements should be performed. Thirteen specific outcomes were chosen, including acute complications occurring within 30 days of acute myocardial infarction, coronary artery bypass grafting surgery, or percutaneous coronary intervention; and longitudinal outcomes for up to 5 years for patient‐reported health status (Seattle Angina Questionnaire [SAQ‐7], elements of Rose Dyspnea Score, and Patient Health Questionnaire [PHQ‐2]), cardiovascular hospital admissions, cardiovascular procedures, renal failure, and mortality. Baseline demographic, cardiovascular disease, and comorbidity information is included to improve the interpretability of comparisons

    Еволюція рослинного світу в природному і культигенному середовищі

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    У ході засідань Міжнародної наукової конференції “Еволюція рослинного світу в природному і культигенному середовищі”, присвяченої 200-річчю від Дня народження Чарльза Дарвіна, обговорено актуальні питання еволюційної теорії, ботаніки, фізіології рослин, інтродукції, генетики й селекції, екології, збереження і примноження глобального та локального біорізноманіття, лісових культур і фітомеліорації та інших біологічних наук.В ходе заседаний Международной научной конференции “Эволюция растительного мира в естественной и культигенной среде”, посвященной 200-летию со дня рождения Чарльза Дарвина, обсуждены актуальные вопросы эволюционной теории, ботаники, физиологии растений, интродукции, генетики и селекции, экологии, сохранения и приумножения глобального и локального биоразнообразия, лесных культур и фитомелиорации и других биологических наук.During meetings of the International scientific conference “Evolution of the natural and cultivated plants” to devoted a 200-year from the day of birth of Charles Darwin topical problems of the evolutional theory are discussed, including botany, physiology of plants, introduction of plants, genetics and breeding of plants, ecology, preventing the loss of global and loca biodiversity, arboriculture, forest-growing and other biological sciences

    Shrinking a large dataset to identify variables associated with increased risk of Plasmodium falciparum infection in Western Kenya

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    Large datasets are often not amenable to analysis using traditional single-step approaches. Here, our general objective was to apply imputation techniques, principal component analysis (PCA), elastic net and generalized linear models to a large dataset in a systematic approach to extract the most meaningful predictors for a health outcome. We extracted predictors for Plasmodium falciparum infection, from a large covariate dataset while facing limited numbers of observations, using data from the People, Animals, and their Zoonoses (PAZ) project to demonstrate these techniques: data collected from 415 homesteads in western Kenya, contained over 1500 variables that describe the health, environment, and social factors of the humans, livestock, and the homesteads in which they reside. The wide, sparse dataset was simplified to 42 predictors of P. falciparum malaria infection and wealth rankings were produced for all homesteads. The 42 predictors make biological sense and are supported by previous studies. This systematic data-mining approach we used would make many large datasets more manageable and informative for decision-making processes and health policy prioritization
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