Proteases and protease inhibitors involved in plant stress response and acclimation

Proteases play a crucial role in plant defence mechanisms as well as acclimation to changing metabolic demands and environmental cues. Proteases regulate the development of a plant from germination through to senescence and plant death. In this thesis the role of proteases and their inhibitors in plant response to cold stress and CO2 enrichment were investigated. The activity and inhibition of cysteine proteases (CP), as well as degradation of their potential target proteins was investigated in transgenic tobacco plants expressing the rice cystatin, OC-I. Expression of OC-I caused a longer life span; delayed senescence; significant decrease in in vitro CP activity; a concurrent increase in protein content; and protection from chilling-induced decreases in photosynthesis. An initial proteomics study identified altered abundance of a cyclophilin, a histone, a peptidyl-prolyl cis-trans isomerase and two RuBisCO activase isoforms in OC-I expressing leaves. Immunogold labelling studies revealed that RuBisCO and OC-I is present in RuBisCO vesicular bodies (RVB) that appear to be important in RuBisCO degradation in leaves under optimal and stress conditions. Plants need to respond quickly to changes in the environment that cause changes in the demand for photosynthesis. In this study the effect of CO2 enrichment on photosynthesis-related genes and novel proteases and protease inhibitors regulated by CO2 enrichment and/or development, was investigated. Maize plants grown to maturity with CO2 enrichment showed significant changes in leaf chlorophyll and protein content, increased epidermal cell size, and decreased epidermal cell density. An increased stomatal index in leaves grown at high-CO2 indicates that leaves adjust their stomatal densities through changes in epidermal cell numbers rather than stomatal numbers. Photosynthesis and carbohydrate metabolism were not significantly affected. Developmental stage affected over 3000 transcripts between leaf ranks 3 and 12, while 142 and 90 transcripts were modified by high CO2 in the same leaf ranks respectively. Only 18 transcripts were affected by CO2 enrichment exclusively. Particularly, two novel CO2 -modulated serine protease inhibitors modulated by both sugars and pro-oxidants, were identified. Growth with high CO2 decreased oxidative damage to leaf proteins.Thesis (PhD)--University of Pretoria, 2009.Plant Scienceunrestricte

The protective role of oryzacystatin-1 under abiotic stress

One of the most important photosynthetic enzymes in a plant is ribulose-1,5¬bisphosphate carboxylase/oxygenase (Rubisco), which plays a key role in carbon fixation. Degradation of this enzyme leads to decreased carbon fixation and poor photosynthetic performance by the plant. It is therefore of interest to investigate possible ways of protecting this enzyme during stress conditions in order to generate plants that would perform better under extreme climates. In this study the effect of an expressed, exogenous rice cysteine proteinase inhibitor (OCI) in transformed tobacco plants on Rubisco stability/content under chilling and senescence was investigated. Results showed that there is no significant protective role for exogenous OCI on the degradation/content of Rubisco when tobacco plants were exposed to chilling. This result was found using native gel-based quantification procedures, as well as immuno-blotting, spot densitometric analysis, and a radioactive quantification assay as analysis techniques. The study, however, provided evidence for protection of Rubisco against degradation by expression of OCI under a more severe stress condition, such as senescence using native gel-based quantification procedures as detection techniques. Tobacco plants were also transformed with a newly designed vector allowing expressed OCI to be transported to the chloroplast. Failure to detect so far any OCI-¬expressing transformed plants and the idea that delay of senescence could prove beneficial to farmers by providing a more nutrient-dense crop with higher tolerance against stress-induced cell death are discussed.Dissertation (MSc(Botany))--University of Pretoria, 2006.Plant Scienceunrestricte

Vermindering uitspoeling nutriënten in het Drentsche Aa gebied: Verslaglegging maatregelen op bedrijfsniveau: Demopercelen grasklaver en direct zaaien snijmaïs

Verslag van demonstratieproeven in het Drentsche Aa gebied. Extensief bemest gras gaf 76% van de opbrengst van intensief bemest grasland. De introductie van witte en rode klaver in het extensief bemeste grasland verhoogde in de eerste 2 jaar de opbrengst tot 88% (beweiden) en 94% (maaien) van de opbrengst van intensief bemest grasland. Direct zaaien van snijmais in bestaand grasland ten opzichte zaaien in geploegd grasland gaf gelijke opbrengsten, met hogere voerderwaarde (VEM). Het aantal regenwormen bedroeg bij ploegen 11/m2 ten opzichte van 76/m2 bij direct zaaien. De minerale N blijft bij direct zaaien hoger in de bodem dan bij ploegen, waardoor de kans op uitspoeling kleiner is

People with Multiple Tattoos and/or Piercings Are Not at Increased Risk for HBV or HCV in The Netherlands

BACKGROUND: Although published results are inconsistent, it has been suggested that tattooing and piercing are risk factors for HBV and HCV infections. To examine whether tattooing and piercing do indeed increase the risk of infection, we conducted a study among people with multiple tattoos and/or piercings in The Netherlands who acquired their tattoos and piercings in The Netherlands and/or abroad. METHODS: Tattoo artists, piercers, and people with multiple tattoos and/or piercings were recruited at tattoo conventions, shops (N = 182), and a biannual survey at our STI-outpatient clinic (N = 252) in Amsterdam. Participants were interviewed and tested for anti-HBc and anti-HCV. Determinants of HBV and HCV infections were analysed using logistic regression analysis. RESULTS: The median number of tattoos and piercings was 5 (IQR 2-10) and 2 (IQR 2-4), respectively. Almost 40% acquired their tattoo of piercing abroad. In total, 18/434 (4.2%, 95%CI: 2.64%-6.46%) participants were anti-HBc positive and 1 was anti-HCV positive (0.2%, 95%CI: 0.01%-1.29%). Being anti-HBc positive was independently associated with older age (OR 1.68, 95%CI: 1.03-2.75 per 10 years older) and being born in an HBV-endemic country (OR 7.39, 95%CI: 2.77-19.7). Tattoo- and/or piercing-related variables, like having a tattoo or piercing in an HBV endemic country, surface percentage tattooed, number of tattoos and piercings etc., were not associated with either HBV or HCV. CONCLUSIONS: We found no evidence for an increased HBV/HCV seroprevalence among persons with multiple tattoos and/or piercings, which might be due to the introduction of hygiene guidelines for tattoo and piercing shops in combination with the low observed prevalence of HBV/HCV in the general population. Tattoos and/or piercings, therefore, should not be considered risk factors for HBV/HCV in the Dutch population. These findings imply the importance of implementation of hygiene guidelines in other countries

Systemic Oxidative Stress in Severe Early-Onset Fetal Growth Restriction Associates with Concomitant Pre-Eclampsia, Not with Severity of Fetal Growth Restriction

Background: Placental insufficiency is an important mechanism underlying early-onset fetal growth restriction (eoFGR). Reduced placental function causes impaired metabolic and gaseous exchange. This unfavorable placental environment is among other processes characterized by increased oxidative stress. Systemic free thiols (FT) are known for their reactive oxygen species scavenging capacity, and higher plasma levels of FT are associated with a better outcome in a multitude of ischemic and inflammatory diseases. We aimed to investigate the relationships between systemic FT levels and maternal and perinatal clinical characteristics and outcomes. Study design: In a post hoc analysis of the Dutch Strider study, a cohort of women with eoFGR, we investigated the association between the maternal redox status (FT) levels at study inclusion, placental biomarkers, and maternal and neonatal outcomes in 108 patients. Results: FT were significantly lower in pregnancies complicated with eoFGR with concurrent maternal hypertensive disorders (pregnancy-induced hypertension; ρ = −0.281 p = 0.004, pre-eclampsia; ρ = −0.505 p = 0.000). In addition, lower FT levels were significantly associated with higher systolic (ρ = −0.348 p = 0.001) and diastolic blood pressure (ρ = −0.266 p = 0.014), but not with the severity of eoFGR. FT levels were inversely associated with sFlt (ρ = −0.366, p < 0.001). A strong relation between systemic FT levels and PlGF levels was observed in women with pre-eclampsia at delivery (ρ = 0.452, p = 0.002), which was not found in women without hypertensive disorders (ρ = 0.008, p = 0.958). Conclusions: In women with pregnancies complicated with eoFGR, FT levels reflect the severity of maternal disease related to the underlying placental insufficiency rather than the severity of the placental dysfunction as reflected in eoFGR or perinatal outcomes

Oxidative stress biomarkers in fetal growth restriction with and without preeclampsia

INTRODUCTION: Oxidative stress as observed in fetal growth restriction (FGR) and preeclampsia (PE) can be identified by decreased levels of systemic free thiols (FT) and increased levels of plasma ischemia-modified albumin (IMA), which may serve as biomarkers in maternal blood for pregnancy complications. We evaluate the performance of oxidative stress-associated potential biomarkers for FGR and PE, and their relationship with clinical characteristics.METHODS: A prospective clinical pilot study was performed in healthy controls and women with pregnancies complicated by severe FGR with or without PE. Blood samples were taken directly after inclusion and analyzed for FT; IMA; soluble FMS-like tyrosine kinase-1 (sFlt-1); placenta growth factor (PlGF); and biomarkers like leptin and soluble receptors for advanced glycation end products (sRAGE). Placentas were examined microscopically. Descriptive statistics and receiver operating characteristics statistics were performed.RESULTS: Mothers with both severe FGR and PE had significantly reduced FT levels (p &lt; 0.001) and PlGF levels (p &lt; 0.001), and increased levels of plasma IMA (p &lt; 0.05), sFlt (p &lt; 0.001), leptin (p &lt; 0.05) and sRAGE (p &lt; 0.01) compared to women with FGR only. Systemic FT levels were significantly inversely associated with blood pressure (p &lt; 0.01) and plasma IMA (p &lt; 0.001), leptin (p = 0.01) and sRAGE (p &lt; 0.001). Systemic FT and leptin showed significant discriminative ability to differentiate mothers with both FGR and PE from mothers with uncomplicated pregnancies or pregnancies complicated by FGR only.DISCUSSION: There is a significant discriminative capacity of FT, IMA, leptin and sRAGE that harbor potential as biomarkers of pregnancies complicated by combined FGR and PE.</p

Growth of transcendental entire solution of some q-difference equation

Technical Reports of Mathematical Sciences, Chiba University, Vol.18(2002

Rubisco catalytic properties of wild and domesticated relatives provide scope for improving wheat photosynthesis

Rubisco is a major target for improving crop photosynthesis and yield, yet natural diversity in catalytic properties of this enzyme is poorly understood. Rubisco from 25 genotypes of the Triticeae tribe, including wild relatives of bread wheat (Triticum aestivum), were surveyed to identify superior enzymes for improving photosynthesis in this crop. In vitro Rubisco carboxylation velocity (V c), Michaelis–Menten constants for CO2 (K c) and O2 (K o) and specificity factor (S c/o) were measured at 25 and 35 °C. V c and K c correlated positively, while V c and S c/o were inversely related. Rubisco large subunit genes (rbcL) were sequenced, and predicted corresponding amino acid differences analysed in relation to the corresponding catalytic properties. The effect of replacing native wheat Rubisco with counterparts from closely related species was analysed by modelling the response of photosynthesis to varying CO2 concentrations. The model predicted that two Rubisco enzymes would increase photosynthetic performance at 25 °C while only one of these also increased photosynthesis at 35 °C. Thus, under otherwise identical conditions, catalytic variation in the Rubiscos analysed is predicted to improve photosynthetic rates at physiological CO2 concentrations. Naturally occurring Rubiscos with superior properties amongst the Triticeae tribe can be exploited to improve wheat photosynthesis and crop productivity

Alpine altitude climate treatment for severe and uncontrolled asthma: an EAACI position paper

Currently available European Alpine Altitude Climate Treatment (AACT) programs combine the physical characteristics of altitude with the avoidance of environmental triggers in the alpine climate and a personalized multidisciplinary pulmonary rehabilitation approach. The reduced barometric pressure, oxygen pressure, and air density, the relatively low temperature and humidity, and the increased UV radiation at moderate altitude induce several physiological and immunological adaptation responses. The environmental characteristics of the alpine climate include reduced aeroallergens such as house dust mites (HDM), pollen, fungi, and less air pollution. These combined factors seem to have immunomodulatory effects controlling pathogenic inflammatory responses and favoring less neuro-immune stress in patients with different asthma phenotypes. The extensive multidisciplinary treatment program may further contribute to the observed clinical improvement by AACT in asthma control and quality of life, fewer exacerbations and hospitalizations, reduced need for oral corticosteroids (OCS), improved lung function, decreased airway hyperresponsiveness (AHR), improved exercise tolerance, and improved sinonasal outcomes. Based on observational studies and expert opinion, AACT represents a valuable therapy for those patients irrespective of their asthma phenotype, who cannot achieve optimal control of their complex condition despite all the advances in medical science and treatment according to guidelines, and therefore run the risk of falling into a downward spiral of loss of physical and mental health. In the light of the observed rapid decrease in inflammation and immunomodulatory effects, AACT can be considered as a natural treatment that targets biological pathways

Spatial Pressure: The Manipulation of Fluid Space through the Hybridization of Art and Architecture

I believe that although those trained within the discipline of architecture are skilled at sculpting form and space, art practice is often more successful at manipulating spatial conditions beyond architectural norms to affect the dynamic human body. This research thesis proposes that by employing an art practice methodology to influence the architectural design process then a new type of spatially affective, hybridized architecture might be created. In affect theory, knowledge of the body’s interaction with space and other bodies, and reaction to atmosphere is essential to the understanding of a spatial environment. Knowledge of the body and of spatial relationships are inherent to the architectural discipline and yet art practice is often more successful at challenging and manipulating affective responses. While architecture promotes affective responses from those who inhabit, or move through, built forms, might we employ art practice to enhance these spatial reactions? Spatial Pressure proposes that if the architectural discipline employs sculptural art practice methodology then a new type of successful spatially affective architecture might be created. It also proposes that through the manipulation of fluid space, hybrids of art and architecture can affect the dynamic body and enhance spatial responses. The thesis argues for the development of new modes, methods and markers of creating and analysing affective hybrids in order to manipulate spatial reactions. It argues for a reintegration of the body into architecture through the central method of the creation of human scale, sculptural yet pragmatic, interventions. In this work the observation of the body’s response to these interventions is analysed and reinterpreted with each design move, avoiding direct representation of the body. By employing sculptural practices to create publically activated, art-architecture, the hybridized interventions act to push and pull space and encourage movement through spatial pressure. The body moves, the spatial interventions are static; it is the “in-between” that provides the affective condition. Working in a liminal zone between two disciplines creates challenges and opportunities to enhance affective influences and opens the possibility of altering current norms of architectural practice