31 research outputs found
Organelles genome stability of wheat plantlets produced by anther culture
Plantlets derived from in vitro culture might exhibit somoclonal variation which is often heritable, and molecular variations may be generated in vitro. Since the direction of most studies is toward nuclear genome, there is a little known about the DNA of organelles. This study was conducted to test the genetic stability of wheat organelles genomes for plantlets produced by anther culture using restriction fragment length polymorphism (RFLP) analyses. One of the intergenic regions of cpDNA and one of mtDNA introns were amplified with polymerase chain reaction (PCR). The PCR products were then sequenced and digested with four restriction endonucleases (EcoR1, BamH1, NdeI and Sac1). The amplified product from cpDNA was 1000 bp in size, and digested only with NdeI into two bands with 650 and 350 bp. The amplified product from mtDNA was 1550 bp in size, and digested only with Sac1 into two bands with 1220 and 330 bp. The results obtained showed that no noticeable difference can be detected between doubled haploid plantlets and parental plants at the level of ctDNA and mtDNA organization. It can be concluded that in vitro culture by itself does not systematically generate a cytoplasmic variation in plant cells.Key words: RFLP analysis, wheat plantlets, wheat anther culture, doubled haploids, genetic stability, mitochondria and chloroplast genome
Microscopic Aspects of Stretched Exponential Relaxation (SER) in Homogeneous Molecular and Network Glasses and Polymers
Because the theory of SER is still a work in progress, the phenomenon itself
can be said to be the oldest unsolved problem in science, as it started with
Kohlrausch in 1847. Many electrical and optical phenomena exhibit SER with
probe relaxation I(t) ~ exp[-(t/{\tau}){\beta}], with 0 < {\beta} < 1. Here
{\tau} is a material-sensitive parameter, useful for discussing chemical
trends. The "shape" parameter {\beta} is dimensionless and plays the role of a
non-equilibrium scaling exponent; its value, especially in glasses, is both
practically useful and theoretically significant. The mathematical complexity
of SER is such that rigorous derivations of this peculiar function were not
achieved until the 1970's. The focus of much of the 1970's pioneering work was
spatial relaxation of electronic charge, but SER is a universal phenomenon, and
today atomic and molecular relaxation of glasses and deeply supercooled liquids
provide the most reliable data. As the data base grew, the need for a
quantitative theory increased; this need was finally met by the
diffusion-to-traps topological model, which yields a remarkably simple
expression for the shape parameter {\beta}, given by d*/(d* + 2). At first
sight this expression appears to be identical to d/(d + 2), where d is the
actual spatial dimensionality, as originally derived. The original model,
however, failed to explain much of the data base. Here the theme of earlier
reviews, based on the observation that in the presence of short-range forces
only d* = d = 3 is the actual spatial dimensionality, while for mixed short-
and long-range forces, d* = fd = d/2, is applied to four new spectacular
examples, where it turns out that SER is useful not only for purposes of
quality control, but also for defining what is meant by a glass in novel
contexts. (Please see full abstract in main text
Cryopreservation by encapsulation-dehydration of 'Christmas bush' (Ceratopetalum gummiferum) shoot tips
Christmas bush (Ceratopetalum gummiferum Sm) is a shrubby tree species of the east coast of New South Wales in Australia. It is much prized as a cut flower crop because of its bright, pinky red floral calyces. New varieties are being developed, the storage of which is an important issue. In this study, it was shown that shoot tips sampled from in vitro plantlets withstood cryopreservation using the encapsulation-dehydration technique. The protocol leading to optimal regrowth was the following: excised shoot tips were pretreated for 1 d in the dark on hormone-free Murashige and Skoog (MS) medium with 0.3 M sucrose, then encapsulated in 3% calcium alginate and precultured in liquid MS medium with 0.5 M sucrose for 3d. Precultured beads were dehydrated for 6 h in the air current of the laminar flow cabinet to 24.3% moisture content (fresh weight basis) before rapid immersion in liquid nitrogen. Under these conditions, regrowth of shoot tips after cryopreservation reached 61.4%. Regrowth of cryopreserved shoot tips was not affected by the period of cold acclimation of in vitro mother plants
In vitro propagation and cryostorage of Syzygium francissi (Myrtaceae) by the encapsulation-dehydration method
An efficient procedure for the in vitro propagation and cryogenic conservation of Syzygium francissi was developed. The maximum number of shoots per explant was obtained on a Murashige and Skoog (MS) medium supplemented with 4.5 μM benzyladenine and 0.5 μM indole-3-butyric acid (IBA). The in vitro-propagated shoots produced roots when transferred to MS medium containing IBA, indole-3-acetic acid, or naphthaleneacetic acid at various concentrations. Rooted microshoots were transferred to a coco-peat, perlite, and vermiculite (1:1:1) mixture, and hardened off under greenhouse conditions. Ninety-five percent of rooted shoots successfully acclimatized in the greenhouse. Shoot tips excised from in vitro-grown plants were successfully cryostoraged at -196°C by the encapsulation-dehydration method. A preculture of formed beads on MS medium containing 0.75 M sucrose for 1 d, followed by 6 h dehydration (20% moisture content) led to the highest survival rate after cryostorage for 1 h. This method is a promising technique for in vitro propagation and cryopreservation of shoot tips from in vitro-grown plantlets of S. francissi germplasm
Chronic Limb-Threatening Ischemia in Patients with Type 2 Diabetes: Revascularization Index as a Predictor for Primary Endovascular Intervention Outcome
Nawaf J Shatnawi,1 Nabil A Al-Zoubi,1 Lujain A Al-Bakkar,1 Ammar M Abu-Baker,1 Yousef S Khader,2 Mamoon Al-Omari,3 Mowafeq A El-Heis3 1Department of Surgery, Jordan University of Science and Technology, Irbid, Jordan; 2Department of Community Medicine, Public Health and Family Medicine, Jordan University of Science and Technology, Irbid, Jordan; 3Department of Radiology, Jordan University of Science and Technology, Irbid, JordanCorrespondence: Nawaf J Shatnawi, Department of Surgery, Jordan University of Science and Technology, P.O. Box 3030, Irbid, 22110, Jordan, Tel + 962 795576267, Email [email protected] Nabil A Al-Zoubi, Department of General Surgery/Vascular Surgery, Jordan University of Science and Technology, P.O. Box 3030, Irbid, 22110, Jordan, Tel + 962 795774637, Email [email protected]: Chronic limb-threatening ischemia in patients with diabetes is associated with a high risk of adverse outcomes. The associated co-morbidities, the heterogeneity of foot presentation and the distribution of atherosclerotic lesions led to the emergence of multiple revascularization strategies and scoring systems to improve management outcomes. This study aimed to introduce a new index, the revascularization index (RI), and to assess its predictive value for the outcomes of primary endovascular intervention in patients with type 2 diabetes presenting with chronic limb-threatening ischemia.Patients and Methods: A retrospective electronic medical records review was conducted for patients with type 2 diabetes presenting with chronic limb-threatening ischemia managed at King Abdullah University Hospital by primary endovascular interventions between January 2014 and August 2019. The RI was analyzed for its predictive value for the treatment outcomes.Results: A total of 187 patients were included in this study, with a major lower limb amputation rate of 19.3%. The performance of the RI was excellent in predicting secondary revascularization (AUC = 0.80, 95% CI: 0.73– 0.86, p-value < 0.001), good to predict major amputation (AUC = 0.76, 95% CI: 0.67– 0.85, p-value = 0.047), and poor in predicting death (AUC = 0.46, 95% CI: 0.40– 0.55, p-value = 0.398). RI of < 1.21 was significantly associated with a higher risk of major lower limb amputation (HR = 5.8, 95% CI: 1.25– 26.97, p-value < 0.025), and RI of < 1.3 was associated with a higher risk for secondary revascularization.Conclusion: The RI can be used to predict major adverse lower limb events (MALE). It might be used as a guide for the extent of endovascular interventions for diabetic chronic limb-threatening ischemia with multi-level outflow atherosclerotic disease.Keywords: chronic limb-threatening ischemia, diabetes mellitus, angioplasty, amputation, revascularization inde