Factors affecting expression of soybean sudden death syndrome: Flooding, oxygen level, and ethylene hormone

Soybean [Glycine max (L.) Merrill] sudden death syndrome (SDS), caused by the soilborne fungus Fusarium virguiforme (Fv), is a very damaging disease in North and South America, with average yield losses in the Unites States estimated at 190 million dollars annually between 1999 and 2004. Major SDS outbreaks have coincided with years of extreme flooding, such as 1993, 2008, and 2010, but there is no information about how and why excessive soil moisture is associated with severe SDS. In this study, the first objective was to investigate the effect of different flood regimes on the development of SDS under greenhouse conditions. Flooding was found to influence SDS disease severity and Fv population density in soil, but the overall effect on SDS development depended on duration of the flooding period. Short-term flooding, such as 3 days of continuous flooding or repeated flooding periods of 8 h a week for 3 weeks, generally predisposed soybean seedlings to SDS, whereas continuous flooding for 5 or 7 days resulted in lower SDS severity and lower Fv population in soil, compared to non-flooded controls. Flooding conditions cause a decrease in oxygen levels and build-up of carbon dioxide and toxic compounds in the root zone. The second objective of this study was to test the effect of low oxygen levels, similar to those that may occur during flooding conditions, on the soybean-Fv interaction. A hydroponic system was established in a growth chamber where soybean seedlings were exposed to different oxygen levels and tested for the expression of soybean defense-related genes and Fv virulence genes using qPCR. Soybean seedlings exposed to anaerobic conditions for 12 hours exhibited down-regulation of key defense-related genes, including laccase and pathogenesis related proteins, All Fv virulence genes tested, including pectate lyase, pisatin demethylase, and FvTox1also showed down-regulation in soybean roots exposed to anaerobic conditions for 12 hours. Ethylene is a gaseous hormone involved in multiple plant growth and developmental processes, as well as response to biotic and abiotic stresses. The third objective of this study was to understand the role of ethylene hormone in soybean-Fv interaction. Soybean plants treated with ethephon (ethylene releasing compound) developed less severe SDS symptoms compared to water-treated seedlings, whereas those treated with cobalt chloride (ethylene biosynthesis suppressor) or 1-MCP (ethylene perception suppressor) showed the same or higher SDS foliar severity compared to the water treated control. Ethephon application also resulted in activation of genes involved in ethylene biosynthesis, and genes involved in soybean defense responses, such as phenylpropanoid pathway, pathogenesis related proteins and transcription factors. Cobalt chloride and 1-MCP treatments had little or no effect on these genes. Moreover, ethephon had an inhibitory effect on in-vitro growth of Fv on potato dextrose agar. The fourth objective of this study was to determine the optimum application timing of ethephon to suppress SDS development in greenhouse and field conditions. In the greenhouse, all ethephon applications significantly reduced SDS foliar symptom severity by 50-60% compared to the untreated control in susceptible cultivar Williams82. In field studies conducted in 2015, ethephon application at planting (in-furrow) or after plant emergence (VE growth stage) reduced SDS foliar severity compared to the untreated control. Plots that received ethephon at VE growth stage showed a 15% increase (P=0.08) in yield compared to untreated plots. Overall, the results of this research enhance understanding of how flooding and the accompanied anaerobic conditions affect SDS development, and demonstrate that the ethylene-signaling pathway plays an important role in resistance against SDS. Finally, our findings suggest that the use of plant defense inducers, such as ethephon, can suppress SDS and encourage future investigation on their use for SDS management under filed conditions

In vitro evaluation of the marginal and internal discrepancies of different esthetic restorations

Objective: This study examined the fit of two types of all-ceramic single crowns and indirect composite resin full coverage crowns. Material and Methods: Thirty intact human mandibular first premolars were selected for this study and prepared using a machine to standardize the dimensions and randomly divided into 3 groups. Slip cast (IC) (In-Ceram Zirconia, Vita Zahnfabrik), copy-milled zirconia (CM) (ICE, Zirkonzahn) and indirect composite resin crowns (NECO, HeraeusKulzer, Hanau, Germany), (N=30, 10 per group) were fabricated according to each manufacturer's recommendations. Before cementation, discrepancies were measured at the marginal zone in each crown. Crowns were then cemented with G-Cem capsule self-adhesive luting cement (GC Corporation, Tokyo, Japan). Four positions were marked for each zone (mid-facial, mid-mesial, mid-distal, and mid-lingual) and three measurements were made at each of the four positions yielding to a total of 12 measurements per crown before and after cementation. The measurements were performed at a different magnification using a stereo microscope (SZ11, Olympus, Japan). Marginal, axial and occlusal zone discrepancies (µm) were evaluated after cementation. The data were statistically analyzed using two-way ANOVA and Tukey's test. Results: Before cementation, significantly less marginal discrepancies were noted compared with after cementation in all groups (p;0.05). Occlusal zone discrepancies were significantly higher than those of the marginal and axial zones in all groups (

Pollen-Specific Activation of Arabidopsis Retrogenes Is Associated with Global Transcriptional Reprogramming

Duplications allow for gene functional diversification and accelerate genome evolution. Occasionally, the transposon amplification machinery reverse transcribes the mRNA of a gene, integrates it into the genome, and forms an RNA-duplicated copy: the retrogene. Although retrogenes have been found in plants, their biology and evolution are poorly understood. Here, we identified 251 (216 novel) retrogenes in Arabidopsis thaliana, corresponding to 1% of protein-coding genes. Arabidopsis retrogenes are derived from ubiquitously transcribed parents and reside in gene-rich chromosomal regions. Approximately 25% of retrogenes are cotranscribed with their parents and 3% with head-to-head oriented neighbors. This suggests transcription by novel promoters for 72% of Arabidopsis retrogenes. Many retrogenes reach their transcription maximum in pollen, the tissue analogous to animal spermatocytes, where upregulation of retrogenes has been found previously. This implies an evolutionarily conserved mechanism leading to this transcription pattern of RNA-duplicated genes. During transcriptional repression, retrogenes are depleted of permissive chromatin marks without an obvious enrichment for repressive modifications. However, this pattern is common to many other pollen-transcribed genes independent of their evolutionary origin. Hence, retroposition plays a role in plant genome evolution, and the developmental transcription pattern of retrogenes suggests an analogous regulation of RNA-duplicated genes in plants and animals

Students' Academic Difficulties in Learning a Statistics and Probability Course: The Instructors' View

The purpose of this study is to determine students' academic difficulties in learning a statistics and probability course. The study sample consisted of 24 instructors (male and female) in the Humanities track in the Department of Basic Sciences in the Common First Year (CFY) at King Saud University (KSU).The results showed that students in the Humanities track faced several academic difficulties in learning statistics and probability and these difficulties were concentrated in the lessons of permutation, combination, probability and random variables. The results indicated that all the difficulties that instructors surveyed occurred at a high or very high level and that no single difficulty was located at the medium or lower levels. The results indicated that, from the point of view of the instructors, there were no statistically significant differences in the level of students' academic difficulties in learning statistics and probability related to the type of instructor (male or female), the instructor's experience in the CFY (less than five years, over or equal to five years), and specialization (statistics, mathematics). Keywords: Students' Difficulties, Mathematics' Difficulties, Statistics and Probability. DOI: 10.7176/JEP/10-9-05 Publication date:March 31st 201

NRF2 mediated oxidative stress response activity during early in vitro bovine embryo development

Overcoming oxidative stress is one of the various embryo challenges to survive under suboptimal conditions during in vitro production of bovine embryos. Thus, the present study aimed to examine the ability of preimplantation bovine embryos to activate nuclear factor erythroid-derived 2-like 2 (NFE2L2 or NRF2)-mediated oxidative stress response and trigger their survival under oxidative stress conditions. An in vitro model was used to culture embryos under low (5%) oxygen tension as in bovine oviduct or high oxygen tension (20%), which is widely used in vitro culture of embryos. Early stage embryos including 2-, 4-, 8-, 16-cell and blastocyst stage embryos were generated under low (5%) or high (20%) oxygen level culture conditions. NRF2, NRF2 cytoplasmic inhibitor (KEAP1) and selected NRF2 target antioxidant genes expression were measured in each stage using quantitative real time PCR (qPCR). Reactive oxygen species (ROS) were evaluated in the blastocysts using green fluorescent probe. Our results revealed that the ROS level was high under 20 % compared to 5 % oxygen level in blastocysts. The transcription level of NRF2 and its downstream antioxidant genes was dramatically increased in 8-, 16-cell and blastocyst stage embryos under high compared to low oxygen level, while NRF2 inhibitor showed opposite expression pattern. In order to know whether NRF2 activity is associated with the embryo developmental competence, consequently NRF2 activity was compared in developmentally competent versus incompetent embryos. For this, the mRNA and protein expressions of NRF2 and the transcription level of its downstream antioxidant genes were compared in early (competent) vs. late (incompetent) cleaving 2-cell and blastocyst stage embryos. In the early developing blastocysts accompanied by low ROS level, NRF2 and its antioxidant target genes expression were increased. Likewise, protein expression pattern was observed in similar manner with more active nuclear NRF2. In conclusion, this study demonstrated that under oxidative stress conditions, pre-implantation bovine embryos are able to activate the NRF2-mediated oxidative stress response pathway, which is found to be correlated with their survival under in vitro condition.NRF2 vermittelte oxidative Stressreaktion während der frühen bovinen in vitro Embryoentwicklung Für bovine Embryonen ist das Überwinden von oxidativem Stress eine wichtige Herausforderung um in suboptimalen in vitro Entwicklungsbedingungen überleben zu können. Das Ziel dieser Studie war es, die Reaktionsfähigkeit und Überlebensfähigkeit von pre-implantierten bovinen Embryonen auf den durch den nuclear factor erythroidderived 2-like 2 (NFE2L2 oder NRF2)-vermittelten oxidativen Stress zu untersuchen. Für diese Studie wurde ein in vitro Kulturmodell mit unterschiedlicher Sauerstoffkonzentration (5%, 20%) etabliert. Dabei ähnelte die niedrige Sauerstofftension (5%) der im bovinen Eileiter und die höhere (20%) der die normalerweise zur in vitro Kultur von Embryonen benutzt wird. Frühe embryonal Stadien, 2-, 4-, 8-, 16-Zell- und Blastozystenstadien wurden unter geringen (5%) oder hohen (20%) Sauerstoffkonzentrationen kultiviert. Anschließend wurden die Genexpressionen von NRF2, NRF2 cytoplasmic inhibitor (KEAP1) und ausgewählten NRF2 Antioxidans-Zielgenen in den verschieden Stadien mittels quantitative real time PCR (qPCR) analysiert. Reactive oxygen species (ROS) wurden in Blastozyten mittels green fluorescent probe untersucht. Das Ergebnis zeigte, dass der ROS Spiegel in Blastozysten bei einer Sauerstofftension von 20% höher war im Vergleich zu der 5% Gruppe. Die Expression von NRF2 und seinen nachgeschalteten Antioxidans-Genen war unter einem hohen Sauerstoffspiegel im Vergleich zu einem niedrigeren in 8-, 16- Zell- und Blastozytenstadien dramatisch erhöht. Demgegenüber zeigte NRF2 Inhibition ein gegenteiliges Expressionsmuster. Um festzustellen, ob die NRF2 Aktivität mit der Embryoentwicklungsfähigkeit zusammen hängt, wurde die NRF2 Aktivität im Vergleich von entwicklungsfähigen zu nicht entwicklungsfähigen Embryonen untersucht. Dafür wurden die NRF2 mRNA- und Proteinexpressionen und die der Antioxidans-Gene im Vergleich von früh (kompetent) zu spät (inkompetent) entwickelten 2-Zell- und Blastozytenstadien analysiert. Die Genexpression von NRF2 und deren Antioxidans-Zielgenen war in früh entwickelten Blastozyten bei einem geringen ROS Spiegel erhöht. Ein ähnliches Bild zeigte sich für die Proteinexpression mit einem größeren aktiven Anteil an nuklearem NRF2. Schlussendlich zeigte diese Studie, dass unter oxidativen Stress pre-implantiere bovine Embryonen in der Lage sind den NRF2-vermittelten oxidativen Stressreaktionssignalweg zu aktivieren. Dieser steht in Korrelation zu der Überlebensfähigkeit unter in vitro Bedingungen

Safety of Cystic Fibrosis Patients at Health Care Facilities

Cystic Fibrosis (CF) is one of the most common, life-shortening illnesses; it’s a genetic disease that affects the transport of water and salt across cells and affects various organs such as lungs, liver, and pancreas [1]. Cystic fibrosis patients need safety more than anyone else during their visits to the hospital, so CF patients are classified among one of the most vulnerable groups to get infections from the hospital during their visits. The purpose of this qualitative research is to study the safety of cystic fibrosis patients at hospitals and whether they have the proper safety precautions that they need at the hospital or not. The methods used in the study were reviews, interviews, and surveys - as the data collection method. The results obtained showed that sometimes it’s very challenging to protect the CF patients from getting infections and bacteria from hospital environments, also it showed that different hospitals and medical universities are taking proper and very strict safety precautions for CF patients due to mainly they are following the CF foundation guidelines and some universities are fully accredited by the Cystic Fibrosis Foundation. The study discussed, the safety precautions for CF patients in the clinic, how does the hospital environments affect CF patients, separating CF patients from each other, hand hygiene, nebulizer care for CF inpatients, safety precautions for CF patients during COVID-19 and infection control strategies for CF patients. Safety precautions and efforts of hospitals in dealing with CF patients have been discussed as well. Applying safety precautions for CF patients is challenging for hospitals due to the vulnerability of CF patients and hospitals should take strict actions on safety precautions to ensure the patient’s safety. &nbsp

Rifampin-warfarin interaction in a mitral valve replacement patient receiving rifampin for infective endocarditis: a case report

Warfarin therapy is associated with many drug interactions that may cause a significant alteration in its anticoagulant effect. Rifampin is a widely used antimicrobial that has major interactions with several medications including warfarin due to its strong P-glycoprotein and liver enzyme inducer activity especially on CYP2C9, CYP3A4, CYP1A2 and CYP2C19. We report a case of a 34-year-old Sri Lankan female chronically treated with warfarin for her mitral valve replacement. The patient developed infective endocarditis and was started on a 6-week treatment with rifampin along with other antibiotics. Warfarin dose was increased from 52.5 to 210 mg/week over the course of the rifampin therapy, however, the INR remained subtherapeutic throughout the whole period and reached 2.4 by the end of rifampin therapy. Anticoagulation management was challenging in the period following the end of rifampin therapy as well, and multiple dose adjustments starting with an increase and followed by reduction were required till she was stable on an 80 mg/week warfarin dose 5 weeks post-rifampin therapy. Our findings suggest the importance of close monitoring of warfarin therapy during and after the use of rifampin to minimize the risks of under and over-anticoagulation and improve the safety and efficacy of warfarin therapy.Scopu