bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lipase Activity in Insect Oral Secretions Mediates Defense Responses in Arabidopsis
Authors: Schäfer Martin , Fischer Christine , Meldau Stefan , Seebald Eileen , Oelmüller Ralf , Baldwin Ian T. 
Published: May 2011

AbstractHow plants perceive herbivory is not yet well understood. We investigated early responses of the model plant Arabidopsis (Arabidopsis thaliana) to attack from the generalist grasshopper herbivore, Schistocerca gregaria (Caelifera). When compared with wounding alone, S. gregaria attack and the application of grasshopper oral secretions (GS) to puncture wounds elicited a rapid accumulation of various oxylipins, including 13-hydroperoxy octadecatrienoic acid, 12-oxo-phytodienoic acid (OPDA), jasmonic acid, and jasmonic acid-isoleucine. Additionally, GS increased cytosolic calcium levels, mitogen-activated protein kinase (MPK3 and MPK6) activity, and ethylene emission but not the accumulation of hydrogen peroxide. Although GS contain caeliferin A16:0, a putative elicitor of caeliferan herbivores, treatment with pure, synthetic caeliferin A16:0 did not induce any of the observed responses. With mutant plants, we demonstrate that the observed changes in oxylipin levels are independent of MPK3 and MPK6 activity but that MPK6 is important for the GS-induced ethylene release. Biochemical and pharmacological analyses revealed that the lipase activity of GS plays a central role in the GS-induced accumulation of oxylipins, especially OPDA, which could be fully mimicked by treating puncture wounds only with a lipase from Rhizopus arrhizus. GS elicitation increased the levels of OPDA-responsive transcripts. Because the oral secretions of most insects used to study herbivory-induced responses in Arabidopsis rapidly elicit similar accumulations of OPDA, we suggest that lipids containing OPDA (arabidopsides) play an important role in the activation of herbivory-induced responses.
Vacuolar Ca2+/H+ Transport Activity Is Required for Systemic Phosphate Homeostasis Involving Shoot-to-Root Signaling in Arabidopsis
Authors: Liu Tzu-Yin , Aung Kyaw , Tseng Ching-Ying , Chang Tzu-Yun , Chen Ying-Shin , Chiou Tzyy-Jen 
Published: May 2011

Abstract
Calcium ions (Ca2+) and Ca2+-related proteins mediate a wide array of downstream processes involved in plant responses to abiotic stresses. In Arabidopsis (Arabidopsis thaliana), disruption of the vacuolar Ca2+/H+ transporters CAX1 and CAX3 causes notable alterations in the shoot ionome, including phosphate (Pi) content. In this study, we showed that the cax1/cax3 double mutant displays an elevated Pi level in shoots as a result of increased Pi uptake in a miR399/PHO2-independent signaling pathway. Microarray analysis of the cax1/cax3 mutant suggests the regulatory function of CAX1 and CAX3 in suppressing the expression of a subset of shoot Pi starvation-responsive genes, including genes encoding the PHT1;4 Pi transporter and two SPX domain-containing proteins, SPX1 and SPX3. Moreover, although the expression of several PHT1 genes and PHT1;1/2/3 proteins is not up-regulated in the root of cax1/cax3, results from reciprocal grafting experiments indicate that the cax1/cax3 scion is responsible for high Pi accumulation in grafted plants and that the pht1;1 rootstock is sufficient to moderately repress such Pi accumulation. Based on these findings, we propose that CAX1 and CAX3 mediate a shoot-derived signal that modulates the activity of the root Pi transporter system, likely in part via posttranslational regulation of PHT1;1 Pi transporters.
Cell Wall Damage-Induced Lignin Biosynthesis Is Regulated by a Reactive Oxygen Species- and Jasmonic Acid-Dependent Process in Arabidopsis
Authors: Denness Lucinda , McKenna Joseph Francis , Segonzac Cecile , Wormit Alexandra , Madhou Priya , Bennett Mark , Mansfield John , Zipfel Cyril , Hamann Thorsten 
Published: May 2011

Abstract
The plant cell wall is a dynamic and complex structure whose functional integrity is constantly being monitored and maintained during development and interactions with the environment. In response to cell wall damage (CWD), putatively compensatory responses, such as lignin production, are initiated. In this context, lignin deposition could reinforce the cell wall to maintain functional integrity. Lignin is important for the plant’s response to environmental stress, for reinforcement during secondary cell wall formation, and for long-distance water transport. Here, we identify two stages and several components of a genetic network that regulate CWD-induced lignin production in Arabidopsis (Arabidopsis thaliana). During the early stage, calcium and diphenyleneiodonium-sensitive reactive oxygen species (ROS) production are required to induce a secondary ROS burst and jasmonic acid (JA) accumulation. During the second stage, ROS derived from the NADPH oxidase RESPIRATORY BURST OXIDASE HOMOLOG D and JA-isoleucine generated by JASMONIC ACID RESISTANT1, form a negative feedback loop that can repress each other’s production. This feedback loop in turn seems to influence lignin accumulation. Our results characterize a genetic network enabling plants to regulate lignin biosynthesis in response to CWD through dynamic interactions between JA and ROS.
Nonphosphorylating Glyceraldehyde-3-Phosphate Dehydrogenase Is Phosphorylated in Wheat Endosperm at Serine-404 by an SNF1-Related Protein Kinase Allosterically Inhibited by Ribose-5-Phosphate
Authors: Piattoni Claudia Vanesa , Bustos Diego Martín , Guerrero Sergio Adrián , Iglesias Alberto Álvaro 
Published: May 2011

Abstract
Nonphosphorylating glyceraldehyde-3-phosphate dehydrogenase (np-Ga3PDHase) is a cytosolic unconventional glycolytic enzyme of plant cells regulated by phosphorylation in heterotrophic tissues. After interaction with 14-3-3 proteins, the phosphorylated enzyme becomes less active and more sensitive to regulation by adenylates and inorganic pyrophosphate. Here, we acknowledge that in wheat (Triticum aestivum), np-Ga3PDHase is specifically phosphorylated by the SnRK (SNF1-related) protein kinase family. Interestingly, only the kinase present in heterotrophic tissues (endosperm and shoots, but not in leaves) was found active. The specific SnRK partially purified from endosperm exhibited a requirement for Mg2+ or Mn2+ (being Ca2+ independent), having a molecular mass of approximately 200 kD. The kinase also phosphorylated standard peptides SAMS, AMARA, and SP46, as well as endogenous sucrose synthase, results suggesting that it could be a member of the SnRK1 subfamily. Concurrently, the partially purified wheat SnRK was recognized by antibodies raised against a peptide conserved between SnRK1s from sorghum (Sorghum bicolor) and maize (Zea mays) developing seeds. The wheat kinase was allosterically inhibited by ribose-5-phosphate and, to a lesser extent, by fructose-1,6-bisphosphate and 3-phosphoglycerate, while glucose-6-phosphate (the main effector of spinach [Spinacia oleracea] leaves, SnRK1) and trehalose-6-phosphate produced little or no effect. Results support a distinctive allosteric regulation of SnRK1 present in photosynthetic or heterotrophic plant tissues. After in silico analysis, we constructed two np-Ga3PDHase mutants, S404A and S447A, identifying serine-404 as the target of phosphorylation. Results suggest that both np-Ga3PDHase and the specific kinase could be under control, critically affecting the metabolic scenario involving carbohydrates and reducing power partition and storage in heterotrophic plant cells.
Nicotine dependence, abuse and craving: dimensionality in an Israeli sample
Authors: Shmulewitz Dvora , Keyes Katherine M. , Wall Melanie M. , Aharonovich Efrat , Aivadyan Christina , Greenstein Eliana , Spivak Baruch , Weizman Abraham , Frisch Amos , Grant Bridget F. , Hasin Deborah 
Published: May 2011

ABSTRACTAims  Evidence‐based changes planned for Diagnostic and Statistical Manual 5th edition (DSM‐5) substance use disorders (SUDs) include combining dependence and three of the abuse criteria into one disorder and adding a criterion indicating craving. Because DSM‐IV did not include a category for nicotine abuse, little empirical support is available for aligning the nicotine use disorder criteria with the DSM‐5 criteria for other SUDs.Design  Latent variable analyses, bootstrap tests and likelihood ratio tests were used to explore the unidimensionality, psychometric properties and information of the nicotine criteria.Setting and participants  A sample of household residents selected from the Israeli population register yielded 727 life‐time cigarette smokers.Measurements  DSM‐IV nicotine dependence criteria and proposed abuse and craving criteria, assessed with a structured interview.Findings  Three abuse criteria (hazardous use, social/interpersonal problems and neglect roles) were prevalent among smokers, formed a unidimensional latent trait with nicotine dependence criteria, were intermixed with dependence criteria across the severity spectrum and significantly increased the diagnostic information over the dependence‐only model. A craving criterion was shown to fit well with the other criteria.Conclusion  Similar to findings from research on other substances, nicotine dependence, abuse and craving criteria appear to derive from a common underlying dimension. The results support alignment of nicotine criteria with those for alcohol and drug use disorders in Diagnostic and Statistical Manual 5th edition.
The social norms of birth cohorts and adolescent marijuana use in the United States, 1976–2007
Authors: Keyes Katherine M. , Schulenberg John E. , O'Malley Patrick M. , Johnston Lloyd D. , Bachman Jerald G. , Li Guohua , Hasin Deborah 
Published: May 2011

ABSTRACTAims Studies of the relationship between social norms and marijuana use have generally focused on individual attitudes, leaving the influence of larger societal‐level attitudes unknown. The present study investigated societal‐level disapproval of marijuana use defined by birth cohort or by time‐period.Design Combined analysis of nationally representative annual surveys of secondary school students in the United States conducted from 1976 to 2007 as part of the Monitoring the Future study.Setting In‐school surveys completed by adolescents in the United States.Participants A total of 986 003 adolescents in grades 8, 10 and 12.Measurements Main predictors included the percentage of students who disapproved of marijuana in each birth cohort and time‐period. Multi‐level models with individuals clustered in time‐periods of observation and birth cohorts were modeled, with past‐year marijuana use as the outcome.Findings Results indicated a significant and strong effect of birth cohort disapproval of marijuana use in predicting individual risk of marijuana use, after controlling for individual‐level disapproval, perceived norms towards marijuana and other characteristics. Compared to birth cohorts in which most (87–90.9%) adolescents disapproved of marijuana use, odds of marijuana use were 3.53 times higher in cohorts where fewer than half (42–46.9%) disapproved (99% confidence interval: 2.75, 4.53).Conclusions Individuals in birth cohorts that are more disapproving of marijuana use are less likely to use, independent of their personal attitudes towards marijuana use. Social norms and attitudes regarding marijuana use cluster in birth cohorts, and this clustering has a direct effect on marijuana use even after controlling for individual attitudes and perceptions of norms.
Proteolysis, protein oxidation and protease activity in dry‐cured Xuanwei ham during the salting stages
Authors: Wang Zhenyu , Xu Yansheng , Zhang Jihong , Li Xiang , Lin Zusong , Ma Changwei 
Published: May 2011

SummaryTwenty‐four experimental dry‐cured Xuanwei hams were salted using a standard method for 90 days. The proteolysis, protein oxidation and protease activities in biceps femoris (BF) and semimembranoesus (SM) muscles of dry‐cured Xuanwei ham were investigated during the salting phase. At the end of salting, the salt content increased to 35.2 g kg−1 muscle in BF and 54.2 g kg−1 muscle in SM. During the salting stage, salt soluble proteins were degraded mainly into water soluble proteins that were further broken down to peptides with molecular weights mostly greater than 1 kDa. Although large amounts of smaller peptides and free amino acids were generated, especially when the hams were aged. The carbonyl contents were increased but lower than 1.57 nmol mg−1 proteins in muscles during the salting stage. The cathepsin B, dipeptidyl peptidase I (DPP I), alanyl (AAP), arginyl (RAP) and leucyl (LAP) aminopeptidase all remained active while salt content strongly inhibited cathepsin L and DPP IV in the first 90 days. The results suggested that the salting process promoted the hydrolysis of proteins, and increased the muscle protein oxidation at a slower rate.
Understanding dietary decision‐making in patients attending a secondary prevention clinic following myocardial infarction
Authors: Doyle Barbara , Fitzsimons Donna , McKeown Pascal , McAloon Toni 
Published: May 2011

Aims and objectives.  This study aimed to explore the issues that influence the dietary choices made by patients attending a secondary prevention clinic following a myocardial infarction.Background.  Secondary prevention clinics play an important role in promoting dietary advice, yet evidence suggests that many individuals are neither implementing nor maintaining the lifestyle changes recommended. Research largely focuses on compliance to lifestyle changes in general, and only a small number of quantitative studies address the issues surrounding adherence to dietary advice.Design.  Phenomenology was selected as the most appropriate approach for this qualitative study, enabling patients’ lived experiences of dietary decision‐making to be explored.Method.  A purposive sample of nine participants was selected from a cardiac secondary prevention clinic. Semi‐structured interviews were taped, transcribed and analysed using an interpretative approach.Results.  Data analysis produced six central themes contributing to patients’ decision‐making. Fear, determination and self‐control were enabling factors and poor recall of information, a need for additional support and a lack of will power were disabling factors. Findings suggest that patient motivation and ability to make sustainable dietary change can decline as disabling factors reduce determination and self‐control, and initial fear of their heart condition subsides.Conclusion.  In this study, patients’ motivation regarding dietary decision‐making changed over time and was strongly influenced by a fear of future heart problems.Relevance to clinical practice.  Health care professionals need to understand the temporal nature of decision‐making postmyocardial infarction and adopt a wide repertoire of responsive strategies that support patients to follow a healthy diet in the longer term.
Sortase independent and dependent systems for acquisition of haem and haemoglobin in Listeria monocytogenes
Authors: Xiao Qiaobin , Jiang Xiaoxu , Moore Kyle J. , Shao Yi , Pi Hualiang , Dubail Iharilalao , Charbit Alain , Newton Salete M. , Klebba Phillip E. 
Published: May 2011

SummaryWe studied three Fur‐regulated systems of Listeria monocytogenes: the srtB region, that encodes sortase‐anchored proteins and a putative ABC transporter, and the fhu and hup operons, that produce putative ABC transporters for ferric hydroxamates and haemin (Hn)/haemoglobin (Hb) respectively. Deletion of lmo2185 in the srtB region reduced listerial [59Fe]‐Hn transport, and purified Lmo2185 bound [59Fe]‐Hn (KD = 12 nM), leading to its designation as a Hn/Hb binding protein (hbp2). Purified Hbp2 also acted as a haemophore, capturing and supplying Hn from the environment. Nevertheless, Hbp2 only functioned in [59Fe]‐Hn transport at external concentrations less than 50 nM: at higher Hn levels its uptake occurred with equivalent affinity and rate without Hbp2. Similarly, deletion of sortase A had no effect on ferric siderophore or Hn/Hb transport at any concentration, and the srtA‐independence of listerial Hn/Hb uptake distinguished it from comparable systems of Staphylococcus aureus. In the cytoplasmic membrane, the Hup transporter was specific for Hn: its lipoprotein (HupD) only showed high affinity for the iron porphyrin (KD = 26 nM). Conversely, the FhuD lipoprotein encoded by the fhu operon had broad specificity: it bound both ferric siderophores and Hn, with the highest affinity for ferrioxamine B (KD = 123 nM). Deletions of Hup permease components hupD, hupG or hupDGC reduced Hn/Hb uptake, and complementation of ΔhupC and ΔhupG by chromosomal integration of hupC+ and hupG+ alleles on pPL2 restored growth promotion by Hn/Hb. However, ΔhupDGC did not completely eliminate [59Fe]‐Hn transport, implying the existence of another cytoplasmic membrane Hn transporter. The overall KM of Hn uptake by wild‐type strain EGD‐e was 1 nM, and it occurred at similar rates (Vmax = 23 pmol 109 cells−1 min−1) to those of ferric siderophore transporters. In the ΔhupDGC strain uptake occurred at a threefold lower rate (Vmax = 7 pmol 109 cells−1 min−1). The results show that at low (< 50 nM) levels of Hn, SrtB‐dependent peptidoglycan‐anchored proteins (e.g. Hbp2) bind the porphyrin, and HupDGC or another transporter completes its uptake into the cytoplasm. However, at higher concentrations Hn uptake is SrtB‐independent: peptidoglycan‐anchored binding proteins are dispensable because HupDGC directly absorbs and internalizes Hn. Finally, ΔhupDGC increased the LD50 of L. monocytogenes 100‐fold in the mouse infection model, reiterating the importance of this system in listerial virulence.
Quantitative trait loci analysis reveals a correlation between the ratio of sucrose/raffinose family oligosaccharides and seed vigour in Medicago truncatula
Authors: VANDECASTEELE CÉLINE , TEULAT‐MERAH BÉATRICE , MORÈRE‐LE PAVEN MARIE‐CHRISTINE , LEPRINCE OLIVIER , LY VU BENOIT , VIAU LAURE , LEDROIT LYDIE , PELLETIER SANDRA , PAYET NICOLE , SATOUR PASCALE , LEBRAS CAMILLE , GALLARDO KARINE , HUGUET THIERRY , LIMAMI ANIS M. , PROSPERI JEAN‐MARIE , BUITINK JULIA 
Published: May 2011

ABSTRACTSeed vigour is important for successful establishment and high yield, especially under suboptimal environmental conditions. In legumes, raffinose oligosaccharide family (RFO) sugars have been proposed as an easily available energy reserve for seedling establishment. In this study, we investigated whether the composition or amount of soluble sugars (sucrose and RFO) is part of the genetic determinants of seed vigour of Medicago truncatula using two recombinant inbred line (RIL) populations. Quantitative trait loci (QTL) mapping for germination rate, hypocotyl and radicle growth under water deficit and nutritional stress, seed weight and soluble sugar content was performed using RIL populations LR1 and LR4. Seven of the 12 chromosomal regions containing QTL for germination rate or post‐germinative radicle growth under optimal or stress conditions co‐located with Suc/RFO QTL. A significant negative correlation was also found between seed vigour traits and Suc/RFO. In addition, one QTL that explained 80% of the variation in the ratio stachyose/verbascose co‐located with a stachyose synthase gene whose expression profile in the parental lines could explain the variation in oligosaccharide composition. The correlation and co‐location of Suc/RFO ratio with germination and radicle growth QTL suggest that an increased Suc/RFO ratio in seeds of M. truncatula might negatively affect seed vigour.
Comparative physiology and transcriptional networks underlying the heat shock response in Populus trichocarpa, Arabidopsis thaliana and Glycine max
Authors: WESTON DAVID J. , KARVE ABHIJIT A. , GUNTER LEE E. , JAWDY SARA S. , YANG XIAOHAN , ALLEN SARA M. , WULLSCHLEGER STAN D. 
Published: May 2011

ABSTRACTThe heat shock response continues to be layered with additional complexity as interactions and crosstalk among heat shock proteins (HSPs), the reactive oxygen network and hormonal signalling are discovered. However, comparative analyses exploring variation in each of these processes among species remain relatively unexplored. In controlled environment experiments, photosynthetic response curves were conducted from 22 to 42 °C and indicated that temperature optimum of light‐saturated photosynthesis was greater for Glycine max relative to Arabidopsis thaliana or Populus trichocarpa. Transcript profiles were taken at defined states along the temperature response curves, and inferred pathway analysis revealed species‐specific variation in the abiotic stress and the minor carbohydrate raffinose/galactinol pathways. A weighted gene co‐expression network approach was used to group individual genes into network modules linking biochemical measures of the antioxidant system to leaf‐level photosynthesis among P. trichocarpa, G. max and A. thaliana. Network‐enabled results revealed an expansion in the G. max HSP17 protein family and divergence in the regulation of the antioxidant and heat shock modules relative to P. trichocarpa and A. thaliana. These results indicate that although the heat shock response is highly conserved, there is considerable species‐specific variation in its regulation.
Revealing complexity and specificity in the activation of lipase‐mediated oxylipin biosynthesis: a specific role of the Nicotiana attenuata GLA1 lipase in the activation of jasmonic acid biosynthesis in leaves and roots
Authors: BONAVENTURE GUSTAVO , SCHUCK STEFAN , BALDWIN IAN T. 
Published: May 2011

ABSTRACTThe activation of enzymatic oxylipin biosynthesis upon wounding, herbivory and pathogen attack depends on the biochemical activation of lipases that make polyunsaturated fatty acids (PUFAs) available to lipoxygenases (LOXs). The identity and number of the lipases involved in this process remain controversial and they probably differ among plant species. Analysis of transgenic Nicotiana attenuata plants (ir‐gla1) stably reduced in the expression of the NaGLA1 gene showed that this plastidial glycerolipase is a major supplier of trienoic fatty acids for jasmonic acid (JA) biosynthesis in leaves and roots after wounding and simulated herbivory, but not during infection with the oomycete Phytophthora parasitica (var. nicotianae). NaGLA1 was not essential for the developmental control of JA biosynthesis in flowers and for the biosynthesis of C6 volatiles by the hydroperoxide lyase (HPL) pathway; however, it affected the metabolism of divinyl ethers (DVEs) early during infection with P. parasitica (var. nicotianae) and the accumulation of NaDES1 and NaLOX1 mRNAs. Profiling of lysolipids by LC–MS/MS was consistent with a rapid activation of NaGLA1 and indicated that this lipase utilizes different lipid classes as substrates. The results revealed the complexity and specificity of the regulation of lipase‐mediated oxylipin biosynthesis, highlighting the existence of pathway‐ and stimulus‐specific lipases.