Cryopreservation of sweet potato shoot tips by vitrification

1997 Fall.Covers not scanned.Includes bibliographical references.The conservation of vegetatively propagated germplasm is problematic. In vitro conservation of sweet potato has been achieved using normal and limited growth regimes. However, although the storage of in vitro plants is advantageous, it is not the method of choice for long term conservation because normal growth conditions require frequent subculturing which makes it labor intensive and costly. Also, frequent subculturing over a prolonged period of time may lead to undesirable consequences such as, contamination, selection and chromosomal aberrations. Cryopreservation offers the simplest and most economical way for the conservation of plant germplasm and vitrification is the preferred method to accomplish this. Previously, Towill and Jarret (1992) reported that vitrified sweet potato shoot tips exhibited callus formation and that the vitrification protocol developed included high levels of within and between treatment variability for explant survival. The purpose of this study was therefore to, examine the various steps of the cryopreservation procedure in order to generate a reproducible shoot tip cryopreservation protocol for sweet potato. In vitro grown sweet potato shoot tips were excised at 0, 3 or 10 hr in light after an 8 hr dark period. Excised shoot tips were precultured in 2% sucrose in MS for 24 hr and 0.3, 0.5 or 0.75 M sucrose in MS for an additional 24 hr. Precultured shoot tips were loaded with two different cryoprotective solutions for 20 or 60 min at 22 °C and then dehydrated with a concentrated vitrification solution (PVS2) for various lengths of time at 22 °C. Following dehydration, shoot tips were cooled by placing them along with a small drop of PVS2 on thin strips of aluminum foil, in 0.2 ml PVS2 in polypropylene straws or in 1 ml of PVS2 in cryo-vials. These were then plunged in nitrogen 'slush' (ca. -209 °C). Cryoprotectant-exposed shoot tips as well as vitrified shoot tips were recovered on MS media with various modifications (mineral composition, surfactant/ antioxidant, hormonal content). Another type of vitrification technique, the encapsulation / dehydration vitrification procedure, was also pursued for the cryopreservation of sweet potato shoot tips. The highest survival (67%) of vitrified encapsulated shoot tips was achieved after 4 hr dehydration corresponding to a moisture content of 18.1 %. To our knowledge, this is the first reported survival of cryopreservation of sweet potato shoot tips using the encapsulation / dehydration procedure. For the solution-based vitrification method, shoot tip survival after both the dehydration step and cooling in nitrogen slush was strongly dependent on the preculture condition (sucrose concentration). The best survival was achieved from shoot tips (PI 290657) excised from in vitro plants soon after the 8 hr dark period, with a 24 hr preculture in 0.3 M sucrose prior to loading in 2M glycerol + 0.4 M sucrose for 1 hr and then dehydrated with PVS2 for 16 min at 22 °C respectively. A fast cooling rate was beneficial and this was achieved by placing the shoot tips along with a small drop of PVS2 on thin strips of aluminum foil prior to plunging in nitrogen slush. Survival of cryopreserved shoot tips was promoted significantly (P = 0.0001) in the absence of NH4+ in the recovery medium for 5 days prior to transfer to regular MS medium. In this study, we report an improved vitrification protocol in that survival after dehydration and cooling results in the resumption of shoots initiated directly from treated shoot tips. Most important for any genebank is the regeneration of shoots so as to reduce the risk of somaclonal variation. Using the same recovery medium, for all four lines tested, relatively good survival levels (ranging from 62% - 97 %) were achieved, and most important, all lines regenerated shoots after cooling to cryogenic temperatures

Ethnic differences in psychosis—Lay epidemiology explanations

Background Much research attention has been given to the high rates of psychosis diagnosed in the Black community. However, little has been heard about possible reasons for this from Black African and Caribbean mental health service users themselves. Aims To determine how Black African and Caribbean service users perceive and explain these apparent differences. Methods We conducted four focus groups between 2014 and 2015 with 35 participants from the Black African and Black Caribbean community in Lambeth and Southwark, South East London, diagnosed with a psychotic illness. Recruitment was through a local voluntary sector organization and other community contacts. Results Each group described an elevated risk of psychosis in their community and explanations followed the following themes, with increased rates due to: (a) an accumulation of stressors due to disadvantaged ethnic minority status, (b) further disadvantage due to inequitable experiences of mental health services, (c) an absence of community support and (d) a double stigma: as a result of external discrimination, due to ethnicity, and internal stigma about mental illness from within the Black community itself. Conclusions Black mental health service users attributed an elevated risk of psychosis in their community to an accumulation of stressors directly related to ethnic minority status

Designing biomimetic vehicle-to-pedestrian communication protocols for autonomously operating & parking on-road electric vehicles

Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 125-127).With research institutions from various private, government and academic sectors performing research into autonomous vehicle deployment strategies, the way we think about vehicles must adapt. But what happens when the driver, the main conduit of information transaction between the vehicle and its surroundings, is removed? The EVITA system aims to fill this communication void by giving the autonomous vehicle the means to sense others around it, and react to various stimuli in as intuitive ways as possible by taking design cues from the living world. The system is comprised of various types of sensors (computer vision, UWB beacon tracking, sonar) and actuators (light, sound, mechanical) in order to express recognition of others, announcement of intentions, and portraying the vehicle's general state. All systems are built on the 2 nd version of the 1/2 -scale CityCar concept vehicle, featuring advanced mixed-materials (CFRP + Aluminum) and a significantly more modularized architecture.by Nicholas Pennycooke.S.M

Volunteering during COVID-19 lessons for the future

It gives us great pleasure to contribute to the foreword of the Volunteering during COVID-19 – Lessons for the Future. The research team from the Institute of Education at Dublin City University are very pleased to have been involved in this innovative collaboration with Volunteer Ireland. In managing the project and in partnership with Volunteer Ireland, we followed best practices to deliver an evidence-based report which provides rich and noteworthy information. This is not only relevant in the current post-pandemic climate but also provides a platform for ongoing and additional interrogation of the volunteering sector. The study provides a rich insight into the experiences of volunteers throughout Ireland around their participation in volunteering during the COVID-19 pandemic. It is particularly beneficial in highlighting many benefits of volunteering for both the individual and for communities. During the pandemic, volunteers were the lifeline for many in our society and never before has the work of volunteers received much attention. This research included an online survey sent to every registered volunteer on the national volunteering database, I-VOL, followed by focus group interviews with a range of volunteers from across the country. We are most appreciative of the contributions of the volunteers who took part in the survey and focus group interviews. This research will inform the work of Volunteer Ireland and enable them to share and exchange ideas with Volunteer Centres, volunteers and organisations on what can be done to deal with the challenges that the report raises. Caitriona Pennycook, Dr Justin Rami, Dr Maura Coulter and Dr Peter Tiernan Research Team from the Institute of Education, Dublin City Universit

The impact of smoke exposure on the clinical phenotype of alpha-1 antitrypsin deficiency in Ireland: exploiting a national registry to understand a rare disease.

Individuals with Alpha-1 antitrypsin deficiency (AATD) have mutations in the SERPINA1 gene causing genetic susceptibility to early onset lung and liver disease that may result in premature death. Environmental interactions have a significant impact in determining the disease phenotype and outcome in AATD. The aim of this study was to assess the impact of smoke exposure on the clinical phenotype of AATD in Ireland. Clinical demographics and available thoracic computerised tomography (CT) imaging were detected from 139 PiZZ individuals identified from the Irish National AATD Registry. Clinical information was collected by questionnaire. Data was analysed to assess AATD disease severity and evaluate predictors of clinical phenotype. Questionnaires were collected from 107/139 (77%) and thoracic CT evaluation was available in 72/107 (67.2%). 74% of respondents had severe Chronic Obstructive Pulmonary Disease (COPD) (GOLD stage C or D). Cigarette smoking was the greatest predictor of impairment in FEV1 and DLCO (%predicted) and the extent of emphysema correlated most significantly with DLCO. Interestingly the rate of FEV1 decline was similar in ex-smokers when compared to never-smokers. Passive smoke exposure in childhood resulted in a greater total pack-year smoking history. Radiological evidence of bronchiectasis was a common finding and associated with increasing age. The Irish National AATD Registry facilitates clinical and basic science research of this condition in Ireland. This study illustrates the detrimental effect of smoke exposure on the clinical phenotype of AATD in Ireland and the benefit of immediate smoking cessation at any stage of lung disease

90Y Radioembolization for Hepatic Malignancy in Patients with Previous Biliary Intervention: Multicenter Analysis of Hepatobiliary Infections

PurposeTo determine the frequency of hepatobiliary infections after transarterial radioembolization (TARE) with yttrium 90 (90Y) in patients with liver malignancy and a history of biliary intervention.Materials and MethodsFor this retrospective study, records of all consecutive patients with liver malignancy and history of biliary intervention treated with TARE at 14 centers between 2005 and 2015 were reviewed. Data regarding liver function, 90Y dosimetry, antibiotic prophylaxis, and bowel preparation prophylaxis were collected. Primary outcome was development of hepatobiliary infection.ResultsOne hundred twenty-six patients (84 men, 42 women; mean age, 68.8 years) with primary (n = 39) or metastatic (n = 87) liver malignancy and history of biliary intervention underwent 180 procedures with glass (92 procedures) or resin (88 procedures) microspheres. Hepatobiliary infections (liver abscesses in nine patients, cholangitis in five patients) developed in 10 of the 126 patients (7.9%) after 11 of the 180 procedures (6.1%; nine of those procedures were performed with glass microspheres). All patients required hospitalization (median stay, 12 days; range, 2–113 days). Ten patients required percutaneous abscess drainage, three patients underwent endoscopic stent placement and stone removal, and one patient needed insertion of percutaneous biliary drains. Infections resolved in five patients, four patients died (two from infection and two from cancer progression while infection was being treated), and one patient continued to receive suppressive antibiotics. Use of glass microspheres (P = .02), previous liver resection or ablation (P = .02), and younger age (P = .003) were independently predictive of higher infection risk.ConclusionInfectious complications such as liver abscess and cholangitis are uncommon but serious complications of transarterial radioembolization with 90Y in patients with liver malignancy and a history of biliary intervention.© RSNA, 2018Online supplemental material is available for this article

Artificial Seeds (Principle, Aspects and Applications)

Artificial seeds are artificially encapsulated somatic embryos (usually) or other vegetative parts such as shoot buds, cell aggregates, auxiliary buds, or any other micropropagules which can be sown as a seed and converted into a plant under in vitro or in vivo conditions. An improved artificial seed production technique is considered a valuable alternate technology of propagation in many commercially important crops and a significant method for mass propagation of elite plant genotypes. The production of plant clones multiplied by tissue culture and distributed as artificial seeds could be a useful alternative to the costly F1 hybrids for different plant crops. The delivery of artificial seeds also facilitates issues such as undertaking several ways for scaling up in vitro cultures and acclimatization to ex vitro conditions. The development of an artificial seed technique also provides a great approach for the improvement of various plant species such as trees and crops

Analysis of cell wall proteins regulated in stem of susceptible and resistant tomato species after inoculation with Ralstonia solanacearum: a proteomic approach

Proteomics approach was used to elucidate the molecular interactions taking place at the stem cell wall level when tomato species were inoculated with Ralstonia solanacearum, a causative agent of bacterial wilt. Cell wall proteins from both resistant and susceptible plants before and after the bacterial inoculation were extracted from purified cell wall with salt buffers and separated with 2-D IEF/SDS–PAGE and with 3-D IEF/SDS/SDS–PAGE for basic proteins. The gels stained with colloidal Coomassie revealed varied abundance of protein spots between two species (eight proteins in higher abundance in resistant and six other in susceptible). Moreover, proteins were regulated differentially in response to bacterial inoculation in resistant (seven proteins increased and eight other decreased) as well as in susceptible plants (five proteins elevated and eight other suppressed). Combination of MALDI-TOF/TOF MS and LC-ESI-IonTrap MS/MS lead to the identification of those proteins. Plants responded to pathogen inoculation by elevating the expression of pathogenesis related, other defense related and glycolytic proteins in both species. However, cell wall metabolic proteins in susceptible, and antioxidant, stress related as well as energy metabolism proteins in resistant lines were suppressed. Most of the proteins of the comparative analysis and other randomly picked spots were predicted to have secretion signals except some classical cytosolic proteins

A comparison of the low temperature transcriptomes and CBF regulons of three plant species that differ in freezing tolerance: Solanum commersonii, Solanum tuberosum, and Arabidopsis thaliana

Solanum commersonii and Solanum tuberosum are closely related plant species that differ in their abilities to cold acclimate; whereas S. commersonii increases in freezing tolerance in response to low temperature, S. tuberosum does not. In Arabidopsis thaliana, cold-regulated genes have been shown to contribute to freezing tolerance, including those that comprise the CBF regulon, genes that are controlled by the CBF transcription factors. The low temperature transcriptomes and CBF regulons of S. commersonii and S. tuberosum were therefore compared to determine whether there might be differences that contribute to their differences in ability to cold acclimate. The results indicated that both plants alter gene expression in response to low temperature to similar degrees with similar kinetics and that both plants have CBF regulons composed of hundreds of genes. However, there were considerable differences in the sets of genes that comprised the low temperature transcriptomes and CBF regulons of the two species. Thus differences in cold regulatory programmes may contribute to the differences in freezing tolerance of these two species. However, 53 groups of putative orthologous genes that are cold-regulated in S. commersonii, S. tuberosum, and A. thaliana were identified. Given that the evolutionary distance between the two Solanum species and A. thaliana is 112–156 million years, it seems likely that these conserved cold-regulated genes—many of which encode transcription factors and proteins of unknown function—have fundamental roles in plant growth and development at low temperature

Genetic variants of HvCbf14 are statistically associated with frost tolerance in a European germplasm collection of Hordeum vulgare

Two quantitative trait loci (Fr-H1 and Fr-H2) for frost tolerance (FT) have been discovered on the long arm of chromosome 5H in barley. Two tightly linked groups of CBF genes, known to play a key role in the FT regulatory network in A. thaliana, have been found to co-segregate with Fr-H2. Here, we investigate the allelic variations of four barley CBF genes (HvCbf3, HvCbf6, HvCbf9 and HvCbf14) in a panel of European cultivars, landraces and H. spontaneum accessions. In the cultivars a reduction of nucleotide and haplotype diversities in CBFs compared with the landraces and the wild ancestor H. spontaneum, was evident. In particular, in cultivars the loss of HvCbf9 genetic variants was higher compared to other sequences. In order to verify if the pattern of CBF genetic variants correlated with the level of FT, an association procedure was adopted. The pairwise analysis of linkage disequilibrium (LD) among the genetic variants in four CBF genes was computed to evaluate the resolution of the association procedure. The pairwise plotting revealed a low level of LD in cultivated varieties, despite the tight physical linkage of CBF genes analysed. A structured association procedure based on a general liner model was implemented, including the variants in CBFs, of Vrn-H1, and of two reference genes not involved in FT (α-Amy1 and Gapdh) and considering the phenotypic data for FT. Association analysis recovered two nucleotide variants of HvCbf14 and one nucleotide variant of Vrn-H1 as statistically associated to FT