Differential expression of α-L-arabinofuranosidases during maize (Zea mays L.) root elongation.

Science.gov (United States)

Kozlova, Liudmila V; Gorshkov, Oleg V; Mokshina, Natalia E; Gorshkova, Tatyana A

2015-05-01

Specific α- l -arabinofuranosidases are involved in the realisation of elongation growth process in cells with type II cell walls. Elongation growth in a plant cell is largely based on modification of the cell wall. In type II cell walls, the Ara/Xyl ratio is known to decrease during elongation due to the partial removal of Ara residues from glucuronoarabinoxylan. We searched within the maize genome for the genes of all predicted α-L-arabinofuranosidases that may be responsible for such a process and related their expression to the activity of the enzyme and the amount of free arabinose measured in six zones of a growing maize root. Eight genes of the GH51 family (ZmaABFs) and one gene of the GH3 family (ZmaARA-I) were identified. The abundance of ZmaABF1 and 3-6 transcripts was highly correlated with the measured enzymatic activity and free arabinose content that significantly increased during elongation. The transcript abundances also coincided with the pattern of changes in the Ara/Xyl ratio of the xylanase-extractable glucuronoarabinoxylan described in previous studies. The expression of ZmaABF3, 5 and 6 was especially up-regulated during elongation although corresponding proteins are devoid of the catalytic glutamate at the proper position. ZmaABF2 transcripts were specifically enriched in the root cap and meristem. A single ZmaARA-I gene was not expressed as a whole gene but instead as splice variants that encode the C-terminal end of the protein. Changes in the ZmaARA-I transcript level were rather moderate and had no significant correlation with free arabinose content. Thus, elongation growth of cells with type II cell walls is accompanied by the up-regulation of specific and predicted α-L-arabinofuranosidase genes, and the corresponding activity is indeed pronounced and is important for the modification of glucuronoarabinoxylan, which plays a key role in the modification of the cell wall supramolecular organisation.

Effects of abscisic acid and xanthoxin on elongation and gravitropism in primary roots of Zea mays

Science.gov (United States)

Lee, J. S.; Hasenstein, K. H.; Mulkey, T. J.; Yang, R. L.; Evans, M. L.

1990-01-01

We examined the involvement of abscisic acid (ABA) and xanthoxin (Xan) in maize root gravitropism by (1) testing the ability of ABA to allow positive gravitropism in dark-grown seedlings of the maize cultivar LG11, a cultivar known to require light for positive gravitropism of the primary root, (2) comparing curvature in roots in which half of the cap had been excised and replaced with agar containing either ABA or indole-3-acetic acid (IAA), (3) measuring gravitropism in roots of seedlings submerged in oxygenated solutions of ABA or IAA and (4) testing the effect of Xan on root elongation. Using a variety of methods of applying ABA to the root, we found that ABA did not cause horizontally-oriented primary roots of dark-grown seedlings to become positively gravitropic. Replacing half of the root cap of vertically oriented roots with an agar block containing ABA had little or no effect on curvature relative to that of controls in which the half cap was replaced by a plain agar block. Replacement of the removed half cap with IAA either canceled or reversed the curvature displayed by controls. When light-grown seedlings were submerged in ABA they responded strongly to gravistimulation while those in IAA did not. Xan (up to 0.1 mM) did not affect root elongation. The results indicate that ABA is not a likely mediator of root gravitropism and that the putative ABA precursor, Xan, lacks the appropriate growth-inhibiting properties to serve as a mediator of root gravitropism.

Roothairless5, which functions in maize (Zea mays L.) root hair initiation and elongation encodes a monocot-specific NADPH oxidase.

Science.gov (United States)

Nestler, Josefine; Liu, Sanzhen; Wen, Tsui-Jung; Paschold, Anja; Marcon, Caroline; Tang, Ho Man; Li, Delin; Li, Li; Meeley, Robert B; Sakai, Hajime; Bruce, Wesley; Schnable, Patrick S; Hochholdinger, Frank

2014-09-01

Root hairs are instrumental for nutrient uptake in monocot cereals. The maize (Zea mays L.) roothairless5 (rth5) mutant displays defects in root hair initiation and elongation manifested by a reduced density and length of root hairs. Map-based cloning revealed that the rth5 gene encodes a monocot-specific NADPH oxidase. RNA-Seq, in situ hybridization and qRT-PCR experiments demonstrated that the rth5 gene displays preferential expression in root hairs but also accumulates to low levels in other tissues. Immunolocalization detected RTH5 proteins in the epidermis of the elongation and differentiation zone of primary roots. Because superoxide and hydrogen peroxide levels are reduced in the tips of growing rth5 mutant root hairs as compared with wild-type, and Reactive oxygen species (ROS) is known to be involved in tip growth, we hypothesize that the RTH5 protein is responsible for establishing the high levels of ROS in the tips of growing root hairs required for elongation. Consistent with this hypothesis, a comparative RNA-Seq analysis of 6-day-old rth5 versus wild-type primary roots revealed significant over-representation of only two gene ontology (GO) classes related to the biological functions (i.e. oxidation/reduction and carbohydrate metabolism) among 893 differentially expressed genes (FDR <5%). Within these two classes the subgroups 'response to oxidative stress' and 'cellulose biosynthesis' were most prominently represented. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.

The sensitivity of an hydroponic lettuce root elongation bioassay to metals, phenol and wastewaters.

Science.gov (United States)

Park, Jihae; Yoon, Jeong-Hyun; Depuydt, Stephen; Oh, Jung-Woo; Jo, Youn-Min; Kim, Kyungtae; Brown, Murray T; Han, Taejun

2016-04-01

The root elongation bioassay is one of the most straightforward test methods used for environmental monitoring in terms of simplicity, rapidity and economy since it merely requires filter paper, distilled water and Petri dishes. However, filter paper as a support material is known to be problematic as it can reduce the sensitivity of the test. The newly developed hydroponic method reported here differs from the conventional root elongation method (US EPA filter paper method) in that no support material is used and the exposure time is shorter (48 h in this test versus 120 h in the US EPA test). For metals, the hydroponic test method was 3.3 (for Hg) to 57 (for Cu) times more sensitive than the US EPA method with the rank orders of sensitivity, estimated from EC50 values, being Cu≥Cd>Ni≥Zn≥Hg for the former and Hg≥Cu≥Ni≥Cd≥Zn for the latter methods. For phenol, the results did not differ significantly; EC50 values were 124 mg L(-1) and 108-180 mg L(-1) for the hydroponic and filter paper methods, respectively. Lettuce was less sensitive than daphnids to wastewaters, but the root elongation response appears to be wastewater-specific and is especially sensitive for detecting the presence of fluorine. The new hydroponic test thus provides many practical advantages, especially in terms of cost and time-effectiveness requiring only a well plate, a small volume of distilled water and short exposure period; furthermore, no specialist expertise is required. The method is simpler than the conventional EPA technique in not using filter paper which can influence the sensitivity of the test. Additionally, plant seeds have a long shelf-life and require little or no maintenance. Copyright © 2015 Elsevier Inc. All rights reserved.

The locations and amounts of endogenous ions and elements in the cap and elongating zone of horizontally oriented roots of Zea mays L.: an electron-probe EDS study

Science.gov (United States)

Moore, R.; Cameron, I. L.; Hunter, K. E.; Olmos, D.; Smith, N. K.

1987-01-01

We used quantitative electron-probe energy-dispersive x-ray microanalysis to localize endogenous Na, Cl, K, P, S, Mg and Ca in cryofixed and freeze-dried cryosections of the cap (i.e. the putative site of graviperception) and elongating zone (i.e. site of gravicurvature) of horizontally oriented roots of Zea mays. Ca, Na, Cl, K and Mg accumulate along the lower side of caps of horizontally oriented roots. The most dramatic asymmetries of these ions occur in the apoplast, especially the mucilage. We could not detect any significant differences in the concentrations of these ions in the central cytoplasm of columella cells along the upper and lower sides of caps of horizontally-oriented roots. However, the increased amounts of Na, Cl, K and Mg in the longitudinal walls of columella cells along the lower side of the cap suggest that these ions may move down through the columella tissue of horizontally-oriented roots. Ca also accumulates (largely in the mucilage) along the lower side of the elongating zone of horizontally-oriented roots, while Na, P, Cl and K tend to accumulate along the upper side of the elongating zone. Of these ions, only K increases in concentration in the cytoplasm and longitudinal walls of cortical cells in the upper vs lower sides of the elongating zone. These results indicate that (1) gravity-induced asymmetries of ions differ significantly in the cap and elongating zone of graviresponding roots, (2) Ca accumulates along the lower side of the cap and elongating zone of graviresponding roots, (3) increased growth of the upper side of the elongating zone of horizontally-oriented roots correlates positively with increased amounts of K in the cytoplasm and longitudinal walls of cortical cells, and (4) the apoplast (especially the mucilage) may be an important component of the pathway via which ions move in graviresponding rots of Zea mays. These results are discussed relative to mechanisms for graviperception and gravicurvature of roots.

Phytotoxicity of veterinary antibiotics to seed germination and root elongation of crops.

Science.gov (United States)

Pan, Min; Chu, L M

2016-04-01

Large quantities of veterinary antibiotics (VAs) are being used worldwide in agricultural fields through wastewater irrigation and manure application. They cause damages to the ecosystem when discharged into the environment, but there is a lack of information on their toxicity to plants and animals. This study evaluated the phytotoxic effects of five major VAs, namely tetracycline (TC), sulfamethazine (SMZ), norfloxacin (NOR), erythromycin (ERY) and chloramphenicol (CAP), on seed germination and root elongation in lettuce, tomato, carrot and cucumber, and investigated the relationship between their physicochemical properties and phytotoxicities. Results show that these compounds significantly inhibited root elongation (ptest. TC was associated with the highest level of toxicity, followed by NOR, ERY, SMZ and CAP. Regarding crop species, lettuce was found to be sensitive to most of the VAs. The median effect concentration (EC50) of TC, SMZ, NOR, ERY and CAP to lettuce was 14.4, 157, 49.4, 68.8 and 204 mg/L, respectively. A quantitative structure-activity relationship (QSAR) model has been established based on the measured data. It is evident that hydrophobicity was the most important factor governing the phytotoxicity of these compounds to seeds, which could be explained by the polar narcosis mechanism. Lettuce is considered a good biomarker for VAs in the environment. According to the derived equation, phytotoxicities of selected VA compounds on different crops can be calculated, which could be applicable to other VAs. Environmental risks of VAs were summarized based on the phytotoxicity results and other persistent factors. Copyright © 2015 Elsevier Inc. All rights reserved.

Treated wastewater phytotoxicity assessment using Lactuca sativa: Focus on germination and root elongation test parameters.

Science.gov (United States)

Priac, Anne; Badot, Pierre-Marie; Crini, Grégorio

2017-03-01

Sensitive and simple ecotoxicological bioassays like seed germination and root elongation tests are commonly used to evaluate the phytotoxicity of waste and industrial discharge waters. Although the tests are performed following national and international standards, various parameters such as the number of seeds per dish, the test duration or the type of support used remain variable. To be able to make a correct comparison of results from different studies, it is crucial to know which parameter(s) could affect ecotoxicological diagnosis. We tested four different control waters and three seed densities. No significant differences on either germination rate or root elongation endpoints were shown. Nevertheless, we found that the four lettuce cultivars (Appia, batavia dorée de printemps, grosse blonde paresseuse, and Kinemontepas) showed significantly different responses when watered with the same and different metal-loaded industrial discharge water. From the comparison, it is clear that a differential sensitivity scale occurs among not just species but cultivars. Copyright © 2017 Académie des sciences. Published by Elsevier Masson SAS. All rights reserved.

Toxicity Thresholds Based on EDTA Extractable Nickel and Barley Root Elongation in Chinese Soils

Directory of Open Access Journals (Sweden)

Guangyun Zhu

2018-04-01

Full Text Available The uncertainty in the risk assessment of trace metal elements in soils when total metal contents are used can be decreased by assessing their availability and/or extractability when the soils have a high background value or different sources of trace metal elements. In this study, the added water-soluble nickel (Ni toxicity to barley root elongation was studied in 17 representative Chinese soil samples with and without artificial rainwater leaching. The extractability of added Ni in soils was estimated by three sequential extractions with ethylenediaminetetraacetic acid (EDTA. The results showed that the effective concentration of EDTA extractable Ni (EC50, which caused 50% inhibition of barley root elongation, ranged from 46 to 1019 mg/kg in unleached soils and 24 to 1563 mg/kg in leached soils. Regression models for EDTA extractable Ni and total Ni added to soils against soil properties indicated that EDTA extractable Ni was significantly correlated with the total Ni added to soils and that pH was the most important control factor. Regression models for toxicity thresholds based on EDTA extractable Ni against soil properties showed that soil citrate dithionate extractable Fe was more important than soil pH in predicting Ni toxicity. These results can be used to accurately assess the risk of contaminated soils with high background values and/or different Ni sources.

Rapid bioassessment methods for assessing vegetation toxicity at the Savannah River Site - germination tests and root elongation trials

Energy Technology Data Exchange (ETDEWEB)

Specht, W.L.; Klaine, S.J.; Hook, D.D. [and others

1996-01-01

Plants form the basis of all ecosystems including wetlands. Although they are the most abundant life form and are the primary producers for all other organisms, they have received the least attention when it comes to environmental matters. Higher plants have rarely been used in ecotoxicity testing and may not respond in the same manner as algae, which have been used more frequently. The introduction of hazardous waste materials into wetland areas has the potential to alter and damage the ecological processes in these ecosystems. Measuring the impact of these contaminants on higher plants is therefore important and needs further research. Higher plants are useful for detecting both herbicidal toxicity and heavy metal toxicity. For phytotoxicity tests to be practical they must be simple, inexpensive, yet sensitive to a variety of contaminants. A difference between seed germination and root elongation tests is that seed germination tests measure toxicity associated with soils directly, while root elongation tests consider the indirect effects of water-soluble constituents that may be present in site samples.

Cost-effectiveness of root caries preventive treatments.

Science.gov (United States)

Schwendicke, Falk; Göstemeyer, Gerd

2017-01-01

With a growing number of individuals retaining their teeth lifelong, often with periodontitis-induced root surface exposure, there is the need for cost-effective management strategies for root caries lesions. The present study aimed to assess the cost-effectiveness of root caries preventive treatments. Patients were simulated over 10 years using a Markov model. Four treatments were compared: No treatment, daily 225-800ppm fluoride rinses, chlorhexidine (CHX) varnish (2×/year), silver diamine fluoride (SDF) varnish (2×/year). Data from a systematic review were submitted to network meta-analysis for inferring relative efficacies of treatments. The health outcome was years of teeth being free of root caries. A mixed public-private payer perspective within 2016 German healthcare was taken, with costs being estimated from fee item catalogues or based on market prices. Populations with different numbers of teeth and tooth-level risks were modelled. Monte-Carlo microsimulations, univariate- and probabilistic sensitivity analyses were performed. In populations with 16 teeth at risk and low tooth-level risk for root caries, providing no preventive treatment was least costly, but also least effective (130 Euro, 144 years). SDF ranked next, being more costly (180 Euro), but also more effective (151 years). Payers willing to invest 8.30 Euro per root caries-free tooth-year found SDF most cost-effective. CHX varnish and fluoride rinse were not cost-effective. In populations with more teeth and high tooth-level risk, SDF was the most effective and least costly option. Root caries preventive treatments (like SDF) are effective and might even be cost-saving in high risk populations. Application of SDF can be recommended as a cost-saving treatment for prevention of root caries in patients with high risk of root caries. Copyright © 2016 Elsevier Ltd. All rights reserved.

Reactive Oxygen Species Generated by NADPH Oxidases Promote Radicle Protrusion and Root Elongation during Rice Seed Germination

Directory of Open Access Journals (Sweden)

Wen-Yan Li

2017-01-01

Full Text Available Seed germination is a complicated biological process that requires regulation through various enzymatic and non-enzymatic mechanisms. Although it has been recognized that reactive oxygen species (ROS regulate radicle emergence and root elongation in a non-enzymatic manner during dicot seed germination, the role of ROS in monocot seed germination remains unknown. NADPH oxidases (NOXs are the major ROS producers in plants; however, whether and how NOXs regulate rice seed germination through ROS generation remains unclear. Here, we report that diphenyleneiodinium (DPI, a specific NOX inhibitor, potently inhibited embryo and seedling growth—especially that of the radicle and of root elongation—in a dose-dependent manner. Notably, the DPI-mediated inhibition of radicle and root growth could be eliminated by transferring seedlings from DPI to water. Furthermore, ROS production/accumulation during rice seed germination was quantified via histochemistry. Superoxide radicals (O2−, hydrogen peroxide (H2O2 and hydroxyl radicals (•OH accumulated steadily in the coleorhiza, radicle and seedling root of germinating rice seeds. Expression profiles of the nine typical NOX genes were also investigated. According to quantitative PCR, OsNOX5, 7 and 9 were expressed relatively higher. When seeds were incubated in water, OsNOX5 expression progressively increased in the embryo from 12 to 48 h, whereas OsNOX7 and 9 expressions increased from 12 to 24 h and decreased thereafter. As expected, DPI inhibits the expression at predetermined time points for each of these genes. Taken together, these results suggest that ROS produced by NOXs are involved in radicle and root elongation during rice seed germination, and OsNOX5, 7 and 9 could play crucial roles in rice seed germination. These findings will facilitate further studies of the roles of ROS generated by NOXs during seed germination and seedling establishment and also provide valuable information for the

Tall or short? Slender or thick? A plant strategy for regulating elongation growth of roots by low concentrations of gibberellin.

Science.gov (United States)

Tanimoto, Eiichi

2012-07-01

Since the plant hormone gibberellin (GA) was discovered as a fungal toxin that caused abnormal elongation of rice shoots, the physiological function of GA has mainly been investigated in relation to the regulation of plant height. However, an indispensable role for GA in root growth has been elucidated by using severely GA-depleted plants, either with a gene mutation in GA biosynthesis or which have been treated by an inhibitor of GA biosynthesis. The molecular sequence of GA signalling has also been studied to understand GA functions in root growth. This review addresses research progress on the physiological functions of GA in root growth. Concentration-dependent stimulation of elongation growth by GA is important for the regulation of plant height and root length. Thus the endogenous level of GA and/or the GA sensitivity of shoots and roots plays a role in determining the shoot-to-root ratio of the plant body. Since the shoot-to-root ratio is an important parameter for agricultural production, control of GA production and GA sensitivity may provide a strategy for improving agricultural productivity. The sequence of GA signal transduction has recently been unveiled, and some component molecules are suggested as candidate in planta regulatory sites and as points for the artificial manipulation of GA-mediated growth control. This paper reviews: (1) the breakthrough dose-response experiments that show that root growth is regulated by GA in a lower concentration range than is required for shoot growth; (2) research on the regulation of GA biosynthesis pathways that are known predominantly to control shoot growth; and (3) recent research on GA signalling pathways, including GA receptors, which have been suggested to participate in GA-mediated growth regulation. This provides useful information to suggest a possible strategy for the selective control of shoot and root growth, and to explain how GA plays a role in rosette and liana plants with tall or short, and slender

Cadmium and chromium effects on seed germination and root elongation in lettuce, spinach and Swiss chard

Directory of Open Access Journals (Sweden)

Oscar V Bautista

2013-04-01

Full Text Available The La Ramada district and the Bogota River are the principal water resources used for horticultural crop production on the Bogota Plateau, which contain channel pollutant materials, including heavy metals due to domestic and industrial activities on the Plateau. These materials have effects on crop production in this zone. The present research, under laboratory conditions, aimed to evaluate the effect of three concentrations (25, 35 and 50 µM L-1 of cadmium (Cd and chromium (Cr on imbibition, seed germination and root elongation in lettuce (Lactuca sativa var. Batavia, Swiss chard (Beta vulgaris var. cicla "White Ribbed", and spinach (Spinacia oleracea Hib. 424, three species widely cultivated on the Plateau. The three species used for evaluation showed a differential susceptibility response to Cd and Cr. In lettuce, fresh weight increase (imbibition was lower with all Cd concentrations at the last day of observation and at 25 µM L-1 of Cd in Swiss chard. Cadmium reduced seed germination by up to 46%, 97% and 8% in Swiss chard, lettuce and spinach, respectively. Also, root elongation decreased in Cd treatments by up to 57%, 89% and 56%, for Swiss chard, lettuce and spinach, respectively. Chromium, which showed fewer negative effects, decreased germination by up to 29% in Swiss chard, 6% in lettuce and 34% in spinach, as compared to the control

Multi-omics analysis identifies genes mediating the extension of cell walls in the Arabidopsis thaliana root elongation zone

DEFF Research Database (Denmark)

Wilson, Michael H; Holman, Tara J; Sørensen, Iben

2015-01-01

Plant cell wall composition is important for regulating growth rates, especially in roots. However, neither analyses of cell wall composition nor transcriptomes on their own can comprehensively reveal which genes and processes are mediating growth and cell elongation rates. This study reveals...... the benefits of carrying out multiple analyses in combination. Sections of roots from five anatomically and functionally defined zones in Arabidopsis thaliana were prepared and divided into three biological replicates. We used glycan microarrays and antibodies to identify the major classes of glycans......)cellular localization of many epitopes. Extensins were localized in epidermal and cortex cell walls, while AGP glycans were specific to different tissues from root-hair cells to the stele. The transcriptome analysis found several gene families peaking in the REZ. These included a large family of peroxidases (which...

Characterisation of the oxygen fluxes in the division, elongation and mature zones of Vitis roots: influence of oxygen availability.

Science.gov (United States)

Mancuso, Stefano; Boselli, Maurizio

2002-03-01

Oxygen fluxes into and from root cells of Vitis rupestris (flooding sensitive), V. riparia (flooding tolerant) and V. vinifera (medium tolerance to flooding) were measured under different levels of O2 availability using a recently developed polarographic O2-selective, vibrating-microelectrode system. The system enables fluxes to be measured with a spatial resolution of 2-3 microm and a temporal resolution of 10 s. No difference in root porosity was found among the genotypes when grown for 30 days in an aerated solution. Under normoxic conditions, O2 influx was characterised by two distinct peaks, one in the division zone and the other in the elongation zone of the roots. This pattern was found in all three species studied, although the fluxes showed a different magnitude. The peak in the elongation zone coincided with maximum relative elemental growth rates. When the energetics of the cell was disturbed by cyanide, both growth and oxygen O2 influxes ceased at the same time. Under hypoxic conditions, V. riparia plants showed a precise strategy directed toward the maintenance of enough O2 for the respiratory needs of mitosis in the apical meristem of the roots. Thus, whereas in the division zone of V. rupestris and V. vinifera, at bulk O2 concentrations of 0.094 mol x m(-3), the O2 influx was reduced by 70.5 and 38.5%, respectively, for V. riparia no variation in the O2 influx was detected down to bulk O2 concentrations of 0.078 mol x m(-3). Moreover, in accordance with the different tolerances of the plants, the Vitis genotypes were found to differ in their radial O2 loss from the adventitious roots when in an O2-free environment. The results are discussed in terms of possible mechanisms of response to anoxia in Vitis species with different tolerances to flooding.

Long-term control of root growth

Science.gov (United States)

Burton, Frederick G.; Cataldo, Dominic A.; Cline, John F.; Skiens, W. Eugene

1992-05-26

A method and system for long-term control of root growth without killing the plants bearing those roots involves incorporating a 2,6-dinitroaniline in a polymer and disposing the polymer in an area in which root control is desired. This results in controlled release of the substituted aniline herbicide over a period of many years. Herbicides of this class have the property of preventing root elongation without translocating into other parts of the plant. The herbicide may be encapsulated in the polymer or mixed with it. The polymer-herbicide mixture may be formed into pellets, sheets, pipe gaskets, pipes for carrying water, or various other forms. The invention may be applied to other protection of buried hazardous wastes, protection of underground pipes, prevention of root intrusion beneath slabs, the dwarfing of trees or shrubs and other applications. The preferred herbicide is 4-difluoromethyl-N,N-dipropyl-2,6-dinitro-aniline, commonly known as trifluralin.

Film dosimetry of small elongated electron beams for treatment planning

International Nuclear Information System (INIS)

Niroomand-Rad, A.

1989-01-01

The characteristics of 5, 7, 10, 12, 15, and 18 Mev electron beams for small elongated fields of dimensions L x W (where L=1, 2, 3, 4, 5, and 10 cm; and W=1, 2, 3, 4, 5, and 10 cm) have been studied. Film dosimetry and parallel-plate ion chamber measurements have been used to obtain various dose parameters. Selective results of a series of systematic measurements for central axis depth dose data, uniformity index, field flatness, and relative output factors of small elongated electron beams are reported. The square-root method is employed to predict the beam data of small elongated electron fields from corresponding small square electron fields using film dosimetry. The single parameter area/perimeter radio A/P is used to characterize the relative output factors of elongated electron beams. It is our conclusion that for clinical treatment planning square-root method may be applied with caution in determining the beam characteristics of small elongated electron fields from film dosimetry. The calculated and estimated relative output factors from square-root method and A/P ratio are in good agreement and show agreement to within 1% with the measured film values

SHOEBOX Modulates Root Meristem Size in Rice through Dose-Dependent Effects of Gibberellins on Cell Elongation and Proliferation.

Science.gov (United States)

Li, Jintao; Zhao, Yu; Chu, Huangwei; Wang, Likai; Fu, Yanru; Liu, Ping; Upadhyaya, Narayana; Chen, Chunli; Mou, Tongmin; Feng, Yuqi; Kumar, Prakash; Xu, Jian

2015-08-01

Little is known about how the size of meristem cells is regulated and whether it participates in the control of meristem size in plants. Here, we report our findings on shoebox (shb), a mild gibberellin (GA) deficient rice mutant that has a short root meristem size. Quantitative analysis of cortical cell length and number indicates that shb has shorter, rather than fewer, cells in the root meristem until around the fifth day after sowing, from which the number of cortical cells is also reduced. These defects can be either corrected by exogenous application of bioactive GA or induced in wild-type roots by a dose-dependent inhibitory effect of paclobutrazol on GA biosynthesis, suggesting that GA deficiency is the primary cause of shb mutant phenotypes. SHB encodes an AP2/ERF transcription factor that directly activates transcription of the GA biosynthesis gene KS1. Thus, root meristem size in rice is modulated by SHB-mediated GA biosynthesis that regulates the elongation and proliferation of meristem cells in a developmental stage-specific manner.

SHOEBOX Modulates Root Meristem Size in Rice through Dose-Dependent Effects of Gibberellins on Cell Elongation and Proliferation.

Directory of Open Access Journals (Sweden)

Jintao Li

2015-08-01

Full Text Available Little is known about how the size of meristem cells is regulated and whether it participates in the control of meristem size in plants. Here, we report our findings on shoebox (shb, a mild gibberellin (GA deficient rice mutant that has a short root meristem size. Quantitative analysis of cortical cell length and number indicates that shb has shorter, rather than fewer, cells in the root meristem until around the fifth day after sowing, from which the number of cortical cells is also reduced. These defects can be either corrected by exogenous application of bioactive GA or induced in wild-type roots by a dose-dependent inhibitory effect of paclobutrazol on GA biosynthesis, suggesting that GA deficiency is the primary cause of shb mutant phenotypes. SHB encodes an AP2/ERF transcription factor that directly activates transcription of the GA biosynthesis gene KS1. Thus, root meristem size in rice is modulated by SHB-mediated GA biosynthesis that regulates the elongation and proliferation of meristem cells in a developmental stage-specific manner.

Effects of glucose and ethylene on root hair initiation and elongation in lettuce (Lactuca sativa L.) seedlings.

Science.gov (United States)

Harigaya, Wakana; Takahashi, Hidenori

2018-05-01

Root hair formation occurs in lettuce seedlings after transfer to an acidic medium (pH 4.0). This process requires cortical microtubule (CMT) randomization in root epidermal cells and the plant hormone ethylene. We investigated the interaction between ethylene and glucose, a new signaling molecule in plants, in lettuce root development, with an emphasis on root hair formation. Dark-grown seedlings were used to exclude the effect of photosynthetically produced glucose. In the dark, neither root hair formation nor the CMT randomization preceding it occurred, even after transfer to the acidic medium (pH 4.0). Adding 1-aminocyclopropane-1-carboxylic-acid (ACC) to the medium rescued the induction, while adding glucose did not. Although CMT randomization occurred when glucose was applied together with ACC, it was somewhat suppressed compared to that in ACC-treated seedlings. This was not due to a decrease in the speed of randomization, but due to lowering of the maximum degree of randomization. Despite the negative effect of glucose on ACC-induced CMT randomization, the density and length of ACC-induced root hairs increased when glucose was also added. The hair-cell length of the ACC-treated seedlings was comparable to that in the combined-treatment seedlings, indicating that the increase in hair density caused by glucose results from an increase in the root hair number. Furthermore, quantitative RT-PCR revealed that glucose suppressed ethylene signaling. These results suggest that glucose has a negative and positive effect on the earlier and later stages of root hair formation, respectively, and that the promotion of the initiation and elongation of root hairs by glucose may be mediated in an ethylene-independent manner.

Species differences in ligand specificity of auxin-controlled elongation and auxin transport: comparing Zea and Vigna

Science.gov (United States)

Zhao, Hu; Hertel, Rainer; Ishikawa, Hideo; Evans, Michael L.

2002-01-01

The plant hormone auxin affects cell elongation in both roots and shoots. In roots, the predominant action of auxin is to inhibit cell elongation while in shoots auxin, at normal physiological levels, stimulates elongation. The question of whether the primary receptor for auxin is the same in roots and shoots has not been resolved. In addition to its action on cell elongation in roots and shoots, auxin is transported in a polar fashion in both organs. Although auxin transport is well characterized in both roots and shoots, there is relatively little information on the connection, if any, between auxin transport and its action on elongation. In particular, it is not clear whether the protein mediating polar auxin movement is separate from the protein mediating auxin action on cell elongation or whether these two processes might be mediated by one and the same receptor. We examined the identity of the auxin growth receptor in roots and shoots by comparing the response of roots and shoots of the grass Zea mays L. and the legume Vigna mungo L. to indole-3-acetic acid, 2-naphthoxyacetic acid, 4,6-dichloroindoleacetic acid, and 4,7-dichloroindoleacetic acid. We also studied whether or not a single protein might mediate both auxin transport and auxin action by comparing the polar transport of indole-3-acetic acid and 2-naphthoxyacetic acid through segments from Vigna hypocotyls and maize coleoptiles. For all of the assays performed (root elongation, shoot elongation, and polar transport) the action and transport of the auxin derivatives was much greater in the dicots than in the grass species. The preservation of ligand specificity between roots and shoots and the parallels in ligand specificity between auxin transport and auxin action on growth are consistent with the hypothesis that the auxin receptor is the same in roots and shoots and that this protein may mediate auxin efflux as well as auxin action in both organ types.

Ethylene-auxin interactions regulate lateral root initiation and emergence in Arabidopsis thaliana.

Science.gov (United States)

Ivanchenko, Maria G; Muday, Gloria K; Dubrovsky, Joseph G

2008-07-01

Plant root systems display considerable plasticity in response to endogenous and environmental signals. Auxin stimulates pericycle cells within elongating primary roots to enter de novo organogenesis, leading to the establishment of new lateral root meristems. Crosstalk between auxin and ethylene in root elongation has been demonstrated, but interactions between these hormones in root branching are not well characterized. We find that enhanced ethylene synthesis, resulting from the application of low concentrations of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC), promotes the initiation of lateral root primordia. Treatment with higher doses of ACC strongly inhibits the ability of pericycle cells to initiate new lateral root primordia, but promotes the emergence of existing lateral root primordia: behaviour that is also seen in the eto1 mutation. These effects are correlated with decreased pericycle cell length and increased lateral root primordia cell width. When auxin is applied simultaneously with ACC, ACC is unable to prevent the auxin stimulation of lateral root formation in the root tissues formed prior to ACC exposure. However, in root tissues formed after transfer to ACC, in which elongation is reduced, auxin does not rescue the ethylene inhibition of primordia initiation, but instead increases it by several fold. Mutations that block auxin responses, slr1 and arf7 arf19, render initiation of lateral root primordia insensitive to the promoting effect of low ethylene levels, and mutations that inhibit ethylene-stimulated auxin biosynthesis, wei2 and wei7, reduce the inhibitory effect of higher ethylene levels, consistent with ethylene regulating root branching through interactions with auxin.

Root growth, secondary root formation and root gravitropism in carotenoid-deficient seedlings of Zea mays L

Science.gov (United States)

Ng, Y. K.; Moore, R.

1985-01-01

The effect of ABA on root growth, secondary-root formation and root gravitropism in seedlings of Zea mays was investigated by using Fluridone-treated seedlings and a viviparous mutant, both of which lack carotenoids and ABA. Primary roots of seedlings grown in the presence of Fluridone grew significantly slower than those of control (i.e. untreated) roots. Elongation of Fluridone-treated roots was inhibited significantly by the exogenous application of 1 mM ABA. Exogenous application of 1 micromole and 1 nmole ABA had either no effect or only a slight stimulatory effect on root elongation, depending on the method of application. The absence of ABA in Fluridone-treated plants was not an important factor in secondary-root formation in seedlings less than 9-10 d old. However, ABA may suppress secondary-root formation in older seedlings, since 11-d-old control seedlings had significantly fewer secondary roots than Fluridone-treated seedlings. Roots of Fluridone-treated and control seedlings were graviresponsive. Similar data were obtained for vp-9 mutants of Z. mays, which are phenotypically identical to Fluridone-treated seedlings. These results indicate that ABA is necessary for neither secondary-root formation nor for positive gravitropism by primary roots.

Automated Root Tracking with "Root System Analyzer"

Science.gov (United States)

Schnepf, Andrea; Jin, Meina; Ockert, Charlotte; Bol, Roland; Leitner, Daniel

2015-04-01

Crucial factors for plant development are water and nutrient availability in soils. Thus, root architecture is a main aspect of plant productivity and needs to be accurately considered when describing root processes. Images of root architecture contain a huge amount of information, and image analysis helps to recover parameters describing certain root architectural and morphological traits. The majority of imaging systems for root systems are designed for two-dimensional images, such as RootReader2, GiA Roots, SmartRoot, EZ-Rhizo, and Growscreen, but most of them are semi-automated and involve mouse-clicks in each root by the user. "Root System Analyzer" is a new, fully automated approach for recovering root architectural parameters from two-dimensional images of root systems. Individual roots can still be corrected manually in a user interface if required. The algorithm starts with a sequence of segmented two-dimensional images showing the dynamic development of a root system. For each image, morphological operators are used for skeletonization. Based on this, a graph representation of the root system is created. A dynamic root architecture model helps to determine which edges of the graph belong to an individual root. The algorithm elongates each root at the root tip and simulates growth confined within the already existing graph representation. The increment of root elongation is calculated assuming constant growth. For each root, the algorithm finds all possible paths and elongates the root in the direction of the optimal path. In this way, each edge of the graph is assigned to one or more coherent roots. Image sequences of root systems are handled in such a way that the previous image is used as a starting point for the current image. The algorithm is implemented in a set of Matlab m-files. Output of Root System Analyzer is a data structure that includes for each root an identification number, the branching order, the time of emergence, the parent

1,8-cineole inhibits both proliferation and elongation of BY-2 cultured tobacco cells.

Science.gov (United States)

Yoshimura, Hiroko; Sawai, Yu; Tamotsu, Satoshi; Sakai, Atsushi

2011-03-01

Volatile monoterpenes such as 1,8-cineole inhibit the growth of Brassica campestris seedlings in a dose-dependent manner, and the growth-inhibitory effects are more severe for roots than hypocotyls. The preferential inhibition of root growth may be explained if the compounds inhibit cell proliferation more severely than cell elongation because root growth requires both elongation and proliferation of the constituent cells, whereas hypocotyl growth depends exclusively on elongation of existing cells. In order to examine this possibility, BY-2 suspension-cultured tobacco (Nicotiana tabacum) cells were treated with 1,8-cineole, and the inhibitory effects on cell proliferation and on cell elongation were assessed quantitatively. Treatment with 1,8-cineole lowered both the mitotic index and elongation of the cells in a dose-dependent manner, and the half-maximal inhibitory concentration (IC₅₀) for cell elongation was lower than that for cell proliferation. Moreover, 1,8-cineole also inhibited starch synthesis, with IC₅₀ lower than that for cell proliferation. Thus, the inhibitory effects of 1,8-cineole were not specific to cell proliferation; rather, 1,8-cineole seemed inhibitory to a variety of physiological activities when it was in direct contact with target cells. Based on these results, possible mechanisms for the mode of action of 1,8-cineole and for its preferential inhibition on root growth are discussed.

Light and decapitation effects on in vitro rooting in maize root segments.

Science.gov (United States)

Golaz, F W; Pilet, P E

1985-10-01

The effects of white light and decapitation on the initiation and subsequent emergence and elongation of lateral roots of apical maize (Zea mays L. cv LG 11) root segments have been examined. The formation of lateral root primordium was inhibited by the white light. This inhibition did not depend upon the presence of the primary root tip. However, root decapitation induced a shift of the site of appearance of the most apical primordium towards the root apex, and a strong disturbance of the distribution pattern of primordium volumes along the root axis. White light had a significant effect neither on the distribution pattern of primordium volumes, nor on the period of primordium development (time interval required for the smallest detectable primordia to grow out as secondary roots). Thus, considering the rooting initiation and emergence, the light effect was restricted to the initiation phase only. Moreover, white light reduced lateral root elongation as well as primary root growth.

Effect of heavy metals on inhibition of root elongation in 23 cultivars of flax (Linum usitatissimum L.).

Science.gov (United States)

Soudek, Petr; Katrusáková, Adéla; Sedlácek, Lukás; Petrová, Sárka; Kocí, Vladimír; Marsík, Petr; Griga, Miroslav; Vanek, Tomás

2010-08-01

The effect of toxic metals on seed germination was studied in 23 cultivars of flax (Linum usitatissimum L.). Toxicity of cadmium, cobalt, copper, zinc, nickel, lead, chromium, and arsenic at five different concentrations (0.01-1 mM) was tested by standard ecotoxicity test. Root length was measured after 72 h of incubation. Elongation inhibition, EC50 value, slope, and NOEC values were calculated. Results were evaluated by principal component analysis, a multidimensional statistical method. The results showed that heavy-metal toxicity decreased in the following order: As3+>or=As5+>Cu2+>Cd2+>Co2+>Cr6+>Ni2+>Pb2+>Cr3+>Zn2+.

The effect of ethylene on root growth of Zea mays seedlings

Science.gov (United States)

Whalen, M. C.; Feldman, L. J.

1988-01-01

The control of primary root growth in Zea mays cv. Merit by ethylene was examined. At applied concentrations of ethylene equal to or greater than 0.1 microliter L-1, root elongation during 24 h was inhibited. The half-maximal response occurred at 0.6 microliter L-1 and the response saturated at 6 microliters L-1. Inhibition of elongation took place within 20 min. However, after ethylene was removed, elongation recovered to control values within 15 min. Root elongation was also inhibited by green light. The inhibition caused by a 24-h exposure to ethylene was restricted to the elongating region just behind the apex, with inhibition of cortical cell elongation being the primary contributor to the effect. Based on use of 2,5-norbornadiene, a gaseous competitive inhibitor of ethylene, it was concluded that endogenous ethylene normally inhibits root elongation.

Auxin increases the hydrogen peroxide (H2O2) concentration in tomato (Solanum lycopersicum) root tips while inhibiting root growth

NARCIS (Netherlands)

Ivanchenko, Maria G.; den Os, Desiree; Monshausen, Gabriele B.; Dubrovsky, Joseph G.; Bednarova, Andrea; Krishnan, Natraj

2013-01-01

The hormone auxin and reactive oxygen species (ROS) regulate root elongation, but the interactions between the two pathways are not well understood. The aim of this study was to investigate how auxin interacts with ROS in regulating root elongation in tomato, Solanum lycopersicum. Wild-type and

Graviresponsiveness of surgically altered primary roots of Zea mays

Science.gov (United States)

Maimon, E.; Moore, R.

1991-01-01

We examined the gravitropic responses of surgically altered primary roots of Zea mays to determine the route by which gravitropic inhibitors move from the root tip to the elongating zone. Horizontally oriented roots, from which a 1-mm-wide girdle of epidermis plus 2-10 layers of cortex were removed from the apex of the elongating zone, curve downward. However, curvature occurred only apical to the girdle. Filling the girdle with mucilage-like material transmits curvature beyond the girdle. Vertically oriented roots with a half-girdle' (i.e. the epidermis and 2-10 layers of the cortex removed from half of the circumference of the apex of the elongating zone) curve away from the girdle. Inserting the half-girdle at the base of the elongating zone induces curvature towards the girdle. Filling the half-circumference girdles with mucilage-like material reduced curvature significantly. Stripping the epidermis and outer 2-5 layers of cortex from the terminal 1.5 cm of one side of a primary root induces curvature towards the cut, irrespective of the root's orientation to gravity. This effect is not due to desiccation since treated roots submerged in water also curved towards their cut surface. Coating a root's cut surface with a mucilage-like substance minimizes curvature. These results suggest that the outer cell-layers of the root, especially the epidermis, play an important role in root gravicurvature, and the gravitropic signals emanating from the root tip can move apoplastically through mucilage.

Inhibition of white light of 86Rb+ absorption in the root apex of corn

International Nuclear Information System (INIS)

McKendree, W.L.; Smith, R.C.

1990-01-01

Measurements of cell lengths made at 0.5 millimeter intervals in median longitudinal sections of the primary roots of corn (Zea mays) were used to construct a growth curve. The region 1.5 to 4.0 millimeters from the apex contained the largest number of elongating cells. Absorption of 86 Rb + was measured using intact, dark-grown corn seedlings. Following uptake and exchange, the terminal 8.0 millimeters of each root was cut into four 2.0 millimeter segments. Maximum 86 Rb + uptake occurred in the region from 0.0 to 4.0 millimeter from the root tip. Washing the intact primary root in fresh 2.0 millimolar CaSO 4 for 2 hours prior to uptake augmented the rate of 86 Rb + uptake in all regions. Illumination with white light during washing caused a reduction of 86 Rb + uptake as compared with controls washing in darkness, and the region of greatest light response was the region of elongation. Removal of the coleoptile prior to washing did not prevent the light inhibition of subsequent 86 Rb + uptake. Removal of the root cap prior to washing in light partially reversed the light-induced inhibition of the washing response

High-resolution quantification of root dynamics in split-nutrient rhizoslides reveals rapid and strong proliferation of maize roots in response to local high nitrogen.

Science.gov (United States)

in 't Zandt, Dina; Le Marié, Chantal; Kirchgessner, Norbert; Visser, Eric J W; Hund, Andreas

2015-09-01

The plant's root system is highly plastic, and can respond to environmental stimuli such as high nitrogen (N) in patches. A root may respond to an N patch by selective placement of new lateral roots, and therewith increases root N uptake. This may be a desirable trait in breeding programmes, since it decreases NO3(-) leaching and N2O emission. Roots of maize (Zea mays L.) were grown without N in split-nutrient rhizoslides. One side of the slides was exposed to high N after 15 d of root development, and root elongation was measured for another 15 d, described in a time course model and parameterized. The elongation rates of crown axile roots on the N-treated side of the plant followed a logistic increase to a maximum of 5.3cm d(-1); 95% of the maximum were reached within 4 d. At the same time, on the untreated side, axile root elongation dropped linearly to 1.2cm d(-1) within 6.4 d and stayed constant thereafter. Twice as many lateral roots were formed on the crown axis on the N side compared to the untreated side. Most strikingly, the elongation rates of laterals of the N side increased linearly with most of the roots reaching an asymptote ~8 d after start of the N treatment. By contrast, laterals on the side without N did not show any detectable elongation beyond the first day after their emergence. We conclude that split-nutrient rhizoslides have great potential to improve our knowledge about nitrogen responsiveness and selection for contrasting genotypes. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Proteomics of Maize Root Development.

Science.gov (United States)

Hochholdinger, Frank; Marcon, Caroline; Baldauf, Jutta A; Yu, Peng; Frey, Felix P

2018-01-01

Maize forms a complex root system with structurally and functionally diverse root types that are formed at different developmental stages to extract water and mineral nutrients from soil. In recent years proteomics has been intensively applied to identify proteins involved in shaping the three-dimensional architecture and regulating the function of the maize root system. With the help of developmental mutants, proteomic changes during the initiation and emergence of shoot-borne, lateral and seminal roots have been examined. Furthermore, root hairs were surveyed to understand the proteomic changes during the elongation of these single cell type structures. In addition, primary roots have been used to study developmental changes of the proteome but also to investigate the proteomes of distinct tissues such as the meristematic zone, the elongation zone as well as stele and cortex of the differentiation zone. Moreover, subcellular fractions of the primary root including cell walls, plasma membranes and secreted mucilage have been analyzed. Finally, the superior vigor of hybrid seedling roots compared to their parental inbred lines was studied on the proteome level. In summary, these studies provide novel insights into the complex proteomic interactions of the elaborate maize root system during development.

Proteomics of Maize Root Development

Directory of Open Access Journals (Sweden)

Frank Hochholdinger

2018-03-01

Full Text Available Maize forms a complex root system with structurally and functionally diverse root types that are formed at different developmental stages to extract water and mineral nutrients from soil. In recent years proteomics has been intensively applied to identify proteins involved in shaping the three-dimensional architecture and regulating the function of the maize root system. With the help of developmental mutants, proteomic changes during the initiation and emergence of shoot-borne, lateral and seminal roots have been examined. Furthermore, root hairs were surveyed to understand the proteomic changes during the elongation of these single cell type structures. In addition, primary roots have been used to study developmental changes of the proteome but also to investigate the proteomes of distinct tissues such as the meristematic zone, the elongation zone as well as stele and cortex of the differentiation zone. Moreover, subcellular fractions of the primary root including cell walls, plasma membranes and secreted mucilage have been analyzed. Finally, the superior vigor of hybrid seedling roots compared to their parental inbred lines was studied on the proteome level. In summary, these studies provide novel insights into the complex proteomic interactions of the elaborate maize root system during development.

Effects of locally targeted heavy-ion and laser microbeam on root hydrotropism in Arabidopsis thaliana

International Nuclear Information System (INIS)

Miyazawa, Yutaka; Sakashita, Tetsuya; Funayama, Tomoo

2008-01-01

Classical studies on root hydrotropism have hypothesized the importance of columella cells as well as the de novo gene expression, such as auxin-inducible gene, at the elongation zone in hydrotropism; however, there has been no confirmation that columella cells or auxin-mediated signaling in the elongation zone are necessary for hydrotropism. We examined the role of root cap and elongation zone cells in root hydrotropism using heavy-ion and laser microbeam. Heavy-ion microbeam irradiation of the elongation zone, but not that of the columella cells, significantly and temporarily suppressed the development of hydrotropic curvature. However, laser ablation confirmed that columella cells are indispensable for hydrotropism. Systemic heavy-ion broad-beam irradiation suppressed de novo expression of INDOLE ACETIC ACID 5 gene, but not MIZU-KUSSEI1 gene. Our results indicate that both the root cap and elongation zone have indispensable and functionally distinct roles in root hydrotropism, and that de novo gene expression might be required for hydrotropism in the elongation zone, but not in columella cells. (author)

Succinate dehydrogenase assembly factor 2 is needed for assembly and activity of mitochondrial complex II and for normal root elongation in Arabidopsis.

Science.gov (United States)

Huang, Shaobai; Taylor, Nicolas L; Ströher, Elke; Fenske, Ricarda; Millar, A Harvey

2013-02-01

Mitochondria complex II (succinate dehydrogenase, SDH) plays a central role in respiratory metabolism as a component of both the electron transport chain and the tricarboxylic acid cycle. We report the identification of an SDH assembly factor by analysis of T-DNA insertions in At5g51040, a protein with unknown function that was identified by mass spectrometry analysis as a low abundance mitochondrial protein. This gene is co-expressed with a number of genes encoding mitochondrial proteins, including SDH1-1, and has low partial sequence similarity to human SDHAF2, a protein required for flavin-adenine dinucleotide (FAD) insertion into SDH. In contrast to observations of other SDH deficient lines in Arabidopsis, the sdhaf2 line did not affect photosynthetic rate or stomatal conductance, but instead showed inhibition of primary root elongation with early lateral root emergence, presumably due to the low SDH activity caused by the reduced abundance of SDHAF2. Both roots and leaves showed succinate accumulation but different responses in the abundance of other organic acids and amino acids assayed. Isolated mitochondria showed lowered SDH1 protein abundance, lowered maximal SDH activity and less protein-bound flavin-adenine dinucleotide (FAD) at the molecular mass of SDH1 in the gel separation. The short root phenotype and SDH function of sdhaf2 was fully complemented by transformation with SDHAF2. Application of the SDH inhibitor, malonate, phenocopied the sdhaf2 root architecture in WT. Whole root respiratory assays showed no difference between WT and sdhaf2, but micro-respirometry of the tips of roots clearly showed low oxygen consumption in sdhaf2 which could explain a metabolic deficit responsible for root tip growth. © 2012 The Authors The Plant Journal © 2012 Blackwell Publishing Ltd.

Preventative Valve-Sparing Aortic Root Replacement and Pregnancy Outcome in Marfan Syndrome

OpenAIRE

Sokol, Vesna; Zlopaša, Gordan; Herman, Mislav; Planinić, Pavao; Micevska, Ana

2012-01-01

In Marfan syndrome, with dilatation of the aortic root secondary to an underlying connective tissue defect, pregnancy can cause hemodynamic stress leading to the development of an aortic aneurysm and even a fatal aortic dissection. In the presence of existing aortic root enlargement and a family history of aortic dissection, preventative elective surgery is suggested. Aortic root replacement with or without a valve-sparing procedure is superior to total aortic root replacement with ...

Exploring the preventable causes of unplanned readmissions using root cause analysis

DEFF Research Database (Denmark)

Fluitman, K. S.; van Galen, L. S.; Merten, H

2016-01-01

Importance: Unplanned readmissions within 30 days are a common phenomenon in everyday practice and lead to increasing costs. Although many studies aiming to analyze the probable causes leading to unplanned readmissions have been performed, an in depth-study analyzing the human (healthcare worker...... and unpreventable readmissions. Results: Most root causes for readmission were disease-related (46%), followed by human (healthcare worker)-(33%) and patient-(15%) related root causes. Half of the readmissions studied were considered to be potentially preventable. Preventable readmissions predominantly had human......-related (coordination) failures. Conclusion and relevance: Our study suggests that improving human-related (coordinating) factors contributing to a readmission can potentially decrease the number of preventable readmissions. (C) 2015 European Federation of Internal Medicine. Published by Elsevier B.V. All rights...

Regulation of root development in Arabidopsis thaliana by phytohormone-secreting epiphytic methylobacteria.

Science.gov (United States)

Klikno, Jana; Kutschera, Ulrich

2017-09-01

In numerous experimental studies, seedlings of the model dicot Arabidopsis thaliana have been raised on sterile mineral salt agar. However, under natural conditions, no plant has ever grown in an environment without bacteria. Here, we document that germ-free (gnotobiotic) seedlings, raised on mineral salt agar without sucrose, develop very short root hairs. In the presence of a soil extract that contains naturally occurring microbes, root hair elongation is promoted; this effect can be mimicked by the addition of methylobacteria to germ-free seedlings. Using five different bacterial species (Methylobacterium mesophilicum, Methylobacterium extorquens, Methylobacterium oryzae, Methylobacterium podarium, and Methylobacterium radiotolerans), we show that, over 9 days of seedling development in a light-dark cycle, root development (hair elongation, length of the primary root, branching patterns) is regulated by these epiphytic microbes that occur in the rhizosphere of field-grown plants. In a sterile liquid culture test system, auxin (IAA) inhibited root growth with little effect on hair elongation and significantly stimulated hypocotyl enlargement. Cytokinins (trans-zeatin, kinetin) and ethylene (application of the precursor ACC) likewise exerted an inhibitory effect on root growth but, in contrast to IAA, drastically stimulated root hair elongation. Methylobacteria are phytosymbionts that produce/secrete cytokinins. We conclude that, under real-world conditions (soil), the provision of these phytohormones by methylobacteria (and other epiphytic microbes) regulates root development during seedling establishment.

The Interaction between Auxin and Nitric Oxide Regulates Root Growth in Response to Iron Deficiency in Rice

Directory of Open Access Journals (Sweden)

Huwei Sun

2017-12-01

Full Text Available Fe deficiency (-Fe is a common abiotic stress that affects the root development of plants. Auxin and nitric oxide (NO are key regulator of root growth under -Fe. However, the interactions between auxin and NO regulate root growth in response to Fe deficiency are complex and unclear. In this study, the indole-3-acetic acid (IAA and NO levels in roots, and the responses of root growth in rice to different levels of Fe supply were investigated using wild type (WT, ospin1b and osnia2 mutants. -Fe promoted LR formation but inhibited seminal root elongation. IAA levels, [3H] IAA transport, and expression levels of PIN1a-c genes in roots were reduced under -Fe, suggesting that polar auxin transport from shoots to roots was decreased. Application of IAA to -Fe seedlings restored seminal root length, but not LR density, to levels similar to those under normal Fe (+Fe, and the seminal root length was shorter in two ospin1b mutants relative to WT under +Fe, but not under -Fe, confirming that auxin transport participates in -Fe-inhibited seminal root elongation. Moreover, -Fe-induced LR density and -Fe-inhibited seminal root elongation paralleled NO production in roots. Interestingly, similar NO accumulation and responses of LR density and root elongation were observed in osnia2 mutants compared to WT, and the higher expression of NOA gene under -Fe, suggesting that -Fe-induced NO was generated via the NO synthase-like pathway rather than the nitrate reductase pathway. However, IAA could restore the functions of NO in inhibiting seminal root elongation, but did not replace the role of NO-induced LR formation under -Fe. Overall, our findings suggested that NO functions downstream of auxin in regulating LR formation; NO-inhibited seminal root elongation by decreasing meristem activity in root tips under -Fe, with the involvement of auxin.

Barley root hair growth and morphology in soil, sand, and water solution media and relationship with nickel toxicity.

Science.gov (United States)

Lin, Yanqing; Allen, Herbert E; Di Toro, Dominic M

2016-08-01

Barley, Hordeum vulgare (Doyce), was grown in the 3 media of soil, hydroponic sand solution (sand), and hydroponic water solution (water) culture at the same environmental conditions for 4 d. Barley roots were scanned, and root morphology was analyzed. Plants grown in the 3 media had different root morphology and nickel (Ni) toxicity response. Root elongations and total root lengths followed the sequence soil > sand > water. Plants grown in water culture were more sensitive to Ni toxicity and had greater root hair length than those from soil and sand cultures, which increased root surface area. The unit root surface area as root surface area per centimeter of length of root followed the sequence water > sand > soil and was found to be related with root elongation. Including the unit root surface area, the difference in root elongation and 50% effective concentration were diminished, and percentage of root elongations can be improved with a root mean square error approximately 10% for plants grown in different media. Because the unit root surface area of plants in sand culture is closer to that in soil culture, the sand culture method, not water culture, is recommended for toxicity parameter estimation. Environ Toxicol Chem 2016;35:2125-2133. © 2016 SETAC. © 2016 SETAC.

Preventative valve-sparing aortic root replacement and pregnancy outcome in Marfan syndrome.

Science.gov (United States)

Sokol, Vesna; Zlopasa, Gordan; Herman, Mislav; Planinić, Pavao; Micevska, Ana

2012-06-01

In Marfan syndrome, with dilatation of the aortic root secondary to an underlying connective tissue defect, pregnancy can cause hemodynamic stress leading to the development of an aortic aneurysm and even a fatal aortic dissection. In the presence of existing aortic root enlargement and a family history of aortic dissection, preventative elective surgery is suggested. Aortic root replacement with or without a valve-sparing procedure is superior to total aortic root replacement with prosthetic valve/tube graft. It provides excellent survival with low rates of aortic - valve related complications.

Nitrogen uptake and assimilation by corn roots

International Nuclear Information System (INIS)

Yoneyama, Tadakatsu; Akiyama, Yoko; Kumazawa, Kikuo

1977-01-01

The site of nitrogen uptake in the apical root zone of corn was experimentally investigated. Two experiments were performed. The one is to see the assimilation of nitrate and ammonium and the effects of low temperature on it. The 4-day-old roots were treated with 15 N-labelled inorganic nitrogen of 20 ppm N in 5 x 10 -4 M CaSO 4 solution at 30 deg. C and 0 deg. C. The other is to see the nitrogen uptake at apical root zone and the utilization of newly absorbed nitrogen at the root top. The 4-day-old roots were transferred into 5 x 10 -4 M CaSO 4 solution containing 15 N-labelled ammonium nitrate of 40 ppm N. As a result, the effect of low temperature on the nitrogen uptake appeared to be more drastic in the case of nitrate than ammonium. The 15 N content of amino acids indicates that ammonium is assimilated into amino acids even at 0 deg. C, but nitrate is not. The ammonium nitrogen seemed to be absorbed at both cell dividing and elongating zones. On the other hand, nitrate nitrogen seemed to be strongly absorbed at cell elongating zone. The nitrogen in the apical part may be supplied not only by direct absorption but also by translocation from the basal part. The clear difference was found in the utilization of nitrate and ammonium nitrogen at the root top when the root was elongating. This may be due to the difference of assimilation products of inorganic nitrogen. Newly absorbed ammonium nitrogen is more utilizable for the growth of root top than nitrate nitrogen. (Iwakiri, K.)

Intracellulair Organization: A Prerequisite for Root Hair Elongation and Cell Wall Deposition

NARCIS (Netherlands)

Emons, A.M.C.; Ketelaar, M.J.

2009-01-01

Cell growth requires not only production of matter, but in addition, the targeting, transport, and delivery of this matter to the site of cell expansion. Thus, a proper organization of cell structure, the cytoarchitecture, is a necessity for cell elongation. The actual process of cell growth in a

Strigolactones Stimulate Internode Elongation Independently of Gibberellins1[C][W

Science.gov (United States)

de Saint Germain, Alexandre; Ligerot, Yasmine; Dun, Elizabeth A.; Pillot, Jean-Paul; Ross, John J.; Beveridge, Christine A.; Rameau, Catherine

2013-01-01

Strigolactone (SL) mutants in diverse species show reduced stature in addition to their extensive branching. Here, we show that this dwarfism in pea (Pisum sativum) is not attributable to the strong branching of the mutants. The continuous supply of the synthetic SL GR24 via the root system using hydroponics can restore internode length of the SL-deficient rms1 mutant but not of the SL-response rms4 mutant, indicating that SLs stimulate internode elongation via RMS4. Cytological analysis of internode epidermal cells indicates that SLs control cell number but not cell length, suggesting that SL may affect stem elongation by stimulating cell division. Consequently, SLs can repress (in axillary buds) or promote (in the stem) cell division in a tissue-dependent manner. Because gibberellins (GAs) increase internode length by affecting both cell division and cell length, we tested if SLs stimulate internode elongation by affecting GA metabolism or signaling. Genetic analyses using SL-deficient and GA-deficient or DELLA-deficient double mutants, together with molecular and physiological approaches, suggest that SLs act independently from GAs to stimulate internode elongation. PMID:23943865

Assessing biochar ecotoxicology for soil amendment by root phytotoxicity bioassays.

Science.gov (United States)

Visioli, Giovanna; Conti, Federica D; Menta, Cristina; Bandiera, Marianna; Malcevschi, Alessio; Jones, Davey L; Vamerali, Teofilo

2016-03-01

Soil amendment with biochar has been proposed as effective in improving agricultural land fertility and carbon sequestration, although the characterisation and certification of biochar quality are still crucial for widespread acceptance for agronomic purposes. We describe here the effects of four biochars (conifer and poplar wood, grape marc, wheat straw) at increasing application rates (0.5, 1, 2, 5, 10, 20, 50% w/w) on both germination and root elongation of Cucumis sativus L., Lepidium sativum L. and Sorghum saccharatum Moench. The tested biochars varied in chemical properties, depending on the type and quality of the initial feedstock batch, polycyclic aromatic hydrocarbons (PAHs) being high in conifer and wheat straw, Cd in poplar and Cu in grape marc. We demonstrate that electrical conductivity and Cu negatively affected both germination and root elongation at ≥5% rate biochar, together with Zn at ≥10% and elevated pH at ≥20%. In all species, germination was less sensitive than root elongation, strongly decreasing at very high rates of chars from grape marc (>10%) and wheat straw (>50%), whereas root length was already affected at 0.5% of conifer and poplar in cucumber and sorghum, with marked impairment in all chars at >5%. As a general interpretation, we propose here logarithmic model for robust root phytotoxicity in sorghum, based on biochar Zn content, which explains 66% of variability over the whole dosage range tested. We conclude that metal contamination is a crucial quality parameter for biochar safety, and that root elongation represents a stable test for assessing phytotoxicity at recommended in-field amendment rates (<1-2%).

Allelopathic effect of scarlet pimpernel (anagallis arvensis) on seed germination and radical elongation of mung bean and pearl millet

International Nuclear Information System (INIS)

Salam, I.U.; Ahmed, M.; Ali, S.T.

2011-01-01

The green house based experiments were conducted in the Department of Botany FUUAST, Karachi to study the allelopathic effects of root and shoot leachates of Anagallis arvensis on the two test species viz., bajra and mungbean. The percentage of seed germination, speed of germination and radical elongation of the test species were recorded after 10 days. Both leachates have no effect on seed germination and speed of germination of the test species. Radical elongation of two test species showed different response. Mung radical growth was significantly reduced while bajra radical growth was significantly enhanced by the root leachate of weed. (author)

Stochastic model of template-directed elongation processes in biology.

Science.gov (United States)

Schilstra, Maria J; Nehaniv, Chrystopher L

2010-10-01

We present a novel modular, stochastic model for biological template-based linear chain elongation processes. In this model, elongation complexes (ECs; DNA polymerase, RNA polymerase, or ribosomes associated with nascent chains) that span a finite number of template units step along the template, one after another, with semaphore constructs preventing overtaking. The central elongation module is readily extended with modules that represent initiation and termination processes. The model was used to explore the effect of EC span on motor velocity and dispersion, and the effect of initiation activator and repressor binding kinetics on the overall elongation dynamics. The results demonstrate that (1) motors that move smoothly are able to travel at a greater velocity and closer together than motors that move more erratically, and (2) the rate at which completed chains are released is proportional to the occupancy or vacancy of activator or repressor binding sites only when initiation or activator/repressor dissociation is slow in comparison with elongation. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Plant root and shoot dynamics during subsurface obstacle interaction

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Conn, Nathaniel; Aguilar, Jeffrey; Benfey, Philip; Goldman, Daniel

As roots grow, they must navigate complex underground environments to anchor and retrieve water and nutrients. From gravity sensing at the root tip to pressure sensing along the tip and elongation zone, the complex mechanosensory feedback system of the root allows it to bend towards greater depths and avoid obstacles of high impedance by asymmetrically suppressing cell elongation. Here we investigate the mechanical and physiological responses of roots to rigid obstacles. We grow Maize, Zea mays, plants in quasi-2D glass containers (22cm x 17cm x 1.4cm) filled with photoelastic gel and observe that, regardless of obstacle interaction, smaller roots branch off the primary root when the upward growing shoot (which contains the first leaf) reaches an average length of 40 mm, coinciding with when the first leaf emerges. However, prior to branching, contacts with obstacles result in reduced root growth rates. The growth rate of the root relative to the shoot is sensitive to the angle of the obstacle surface, whereby the relative root growth is greatest for horizontally oriented surfaces. We posit that root growth is prioritized when horizontal obstacles are encountered to ensure anchoring and access to nutrients during later stages of development. NSF Physics of Living Systems.

Control of root system architecture by DEEPER ROOTING 1 increases rice yield under drought conditions.

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Uga, Yusaku; Sugimoto, Kazuhiko; Ogawa, Satoshi; Rane, Jagadish; Ishitani, Manabu; Hara, Naho; Kitomi, Yuka; Inukai, Yoshiaki; Ono, Kazuko; Kanno, Noriko; Inoue, Haruhiko; Takehisa, Hinako; Motoyama, Ritsuko; Nagamura, Yoshiaki; Wu, Jianzhong; Matsumoto, Takashi; Takai, Toshiyuki; Okuno, Kazutoshi; Yano, Masahiro

2013-09-01

The genetic improvement of drought resistance is essential for stable and adequate crop production in drought-prone areas. Here we demonstrate that alteration of root system architecture improves drought avoidance through the cloning and characterization of DEEPER ROOTING 1 (DRO1), a rice quantitative trait locus controlling root growth angle. DRO1 is negatively regulated by auxin and is involved in cell elongation in the root tip that causes asymmetric root growth and downward bending of the root in response to gravity. Higher expression of DRO1 increases the root growth angle, whereby roots grow in a more downward direction. Introducing DRO1 into a shallow-rooting rice cultivar by backcrossing enabled the resulting line to avoid drought by increasing deep rooting, which maintained high yield performance under drought conditions relative to the recipient cultivar. Our experiments suggest that control of root system architecture will contribute to drought avoidance in crops.

Tocotrienol-Rich Fraction Prevents Cell Cycle Arrest and Elongates Telomere Length in Senescent Human Diploid Fibroblasts

Directory of Open Access Journals (Sweden)

Suzana Makpol

2011-01-01

Full Text Available This study determined the molecular mechanisms of tocotrienol-rich fraction (TRF in preventing cellular senescence of human diploid fibroblasts (HDFs. Primary culture of HDFs at various passages were incubated with 0.5 mg/mL TRF for 24 h. Telomere shortening with decreased telomerase activity was observed in senescent HDFs while the levels of damaged DNA and number of cells in G0/G1 phase were increased and S phase cells were decreased. Incubation with TRF reversed the morphology of senescent HDFs to resemble that of young cells with decreased activity of SA-β-gal, damaged DNA, and cells in G0/G1 phase while cells in the S phase were increased. Elongated telomere length and restoration of telomerase activity were observed in TRF-treated senescent HDFs. These findings confirmed the ability of tocotrienol-rich fraction in preventing HDFs cellular ageing by restoring telomere length and telomerase activity, reducing damaged DNA, and reversing cell cycle arrest associated with senescence.

Effect of MET on formation and vigor of wheat roots

International Nuclear Information System (INIS)

Wang Bingkui; Jin Ziyu; Zhao Miaozhen; Zhao Yanshen

1993-01-01

Effect of MET on the formation and vigor of roots of wheat seedlings were studied. The results showed that 50 ∼ 200 ppm MET inhibited vertical elongation of roots, increased root, shoot ratio and enhanced the formation and vigor of roots. But MET had no effect on the dry weight of roots. The activity of peroxidase was decreased and the proportion of assimilates in roots was increased by MET treatment compared with the control

Enhancement of cell wall protein SRPP expression during emergent root hair development in Arabidopsis.

Science.gov (United States)

Uno, Hiroshi; Tanaka-Takada, Natsuki; Sato, Ryosuke; Maeshima, Masayoshi

2017-10-03

SRPP is a protein expressed in seeds and root hairs and is significantly induced in root hairs under phosphate (Pi)-deficient conditions. Root hairs in the knockout mutant srpp-1 display defects, i.e., suppression of cell growth and cell death. Here, we analyzed the expression profile of SRPP during cell elongation of root hairs and compared the transcript levels in several mutants with short root hairs. The mRNA level was increased in wild-type plants and decreased in mutants with short root hairs. Induction of SRPP expression by Pi starvation occurred one or two days later than induction of Pi-deficient sensitive genes, such as PHT1 and PHF1. These results indicate that the expression of SRPP is coordinated with root hair elongation. We hypothesize that SRPP is essential for structural robustness of the cell walls of root hairs.

Temperature sensing by primary roots of maize

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Poff, K. L.

1990-01-01

Zea mays L. seedlings, grown on agar plates at 26 degrees C, reoriented the original vertical direction of their primary root when exposed to a thermal gradient applied perpendicular to the gravity vector. The magnitude and direction of curvature can not be explained simply by either a temperature or a humidity effect on root elongation. It is concluded that primary roots of maize sense temperature gradients in addition to sensing the gravitational force.

Identifying the transition to the maturation zone in three ecotypes of Arabidopsis thaliana roots.

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Cajero Sánchez, Wendy; García-Ponce, Berenice; Sánchez, María de la Paz; Álvarez-Buylla, Elena R; Garay-Arroyo, Adriana

2018-01-01

The Arabidopsis thaliana (hereafter Arabidopsis) root has become a useful model for studying how organ morphogenesis emerge from the coordination and balance of cell proliferation and differentiation, as both processes may be observed and quantified in the root at different stages of development. Hence, being able to objectively identify and delimit the different stages of root development has been very important. Up to now, three different zones along the longitudinal axis of the primary root of Arabidopsis, have been identified: the root apical meristematic zone (RAM) with two domains [the proliferative (PD) and the transition domain (TD)], the elongation zone (EZ) and the maturation zone (MZ). We previously reported a method to quantify the length of the cells of the meristematic and the elongation zone, as well as the boundaries or transitions between the root domains along the growing part of the Arabidopsis root. In this study, we provide a more accurate criterion to identify the MZ. Traditionally, the transition between the EZ to the MZ has been established by the emergence of the first root-hair bulge in the epidermis, because this emergence coincides with cell maturation in this cell type. But we have found here that after the emergence of the first root-hair bulge some cells continue to elongate and we have confirmed this in three different Arabidopsis ecotypes. We established the limit between the EZ and the MZ by looking for the closest cortical cell with a longer length than the average cell length of 10 cells after the cortical cell closest to the epidermal cell with the first root-hair bulge in these three ecotypes. In Col-0 and Ws this cell is four cells above the one with the root hair bulge and, in the Ler ecotype, this cell is five cells above. To unambiguously identifying the site at which cells stop elongating and attain their final length and fate at the MZ, we propose to calculate the length of completely elongated cortical cells counting 10

Effect of Root Moisture Content and Diameter on Root Tensile Properties

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Yang, Yuanjun; Chen, Lihua; Li, Ning; Zhang, Qiufen

2016-01-01

The stabilization of slopes by vegetation has been a topical issue for many years. Root mechanical characteristics significantly influence soil reinforcement; therefore it is necessary to research into the indicators of root tensile properties. In this study, we explored the influence of root moisture content on tensile resistance and strength with different root diameters and for different tree species. Betula platyphylla, Quercus mongolica, Pinus tabulaeformis, and Larix gmelinii, the most popular tree species used for slope stabilization in the rocky mountainous areas of northern China, were used in this study. A tensile test was conducted after root samples were grouped by diameter and moisture content. The results showedthat:1) root moisture content had a significant influence on tensile properties; 2) slightly loss of root moisture content could enhance tensile strength, but too much loss of water resulted in weaker capacity for root elongation, and consequently reduced tensile strength; 3) root diameter had a strong positive correlation with tensile resistance; and4) the roots of Betula platyphylla had the best tensile properties when both diameter and moisture content being controlled. These findings improve our understanding of root tensile properties with root size and moisture, and could be useful for slope stabilization using vegetation. PMID:27003872

Physiological and Biochemical Responses to Aluminum Stress in the Root of a Biodiesel Plant Jatropha curcas L.

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RADITE TISTAMA

2012-03-01

Full Text Available We investigated J. curcas responses to aluminum stress, histochemically and biochemically. Histochemical stainings were observed to analysis aluminum accumulation, lipid peroxidation and the loss of plasma membrane integrity on the surface and tissue of the root apex. Enzymatic analysis was conducted to measure malate content in leaf, root and malate efflux in the medium. We used M. malabathricum as a comparison for Al-tolerance plant. J. curcas root elongation was inhibited by 0.4 mM AlCl3, while M. malabathricum root elongation was inhibited by 0.8 mM AlCl3 treatment. Inhibition of root elongation has high correlation with Al accumulation in the root apex, which caused lipid degradation and cell death. Generally, malate content in J. curcas leaf and root was higher than that in M. malabathricum. In the contrary malate efflux from the root into the medium was lower. J. curcas root has a different pattern compared to M. malabathricum in malate synthesis and malate secretion when treated with a different Al concentration. We categorized J. curcas acc IP3 as more sensitive to aluminum than M. malabathricum.

Root morphology of Ni-treated plants

International Nuclear Information System (INIS)

Leskova, A.; Fargasova, A.; Giehl, R. F. H.; Wiren, N. von

2015-01-01

Plant roots are very important organs in terms of nutrient and water acquisition but they also serve as anchorages for the aboveground parts of the plants. The roots display extraordinary plasticity towards stress conditions as a result of integration of environmental cues into the developmental processes of the roots. Our aim was to investigate the root morphology of Arabidopsis thaliana plants exposed to a particular stress condition, excess Ni supply. We aimed to find out which cellular processes - cell division, elongation and differentiation are affected by Ni, thereby explaining the seen root phenotype. Our results reveal that a distinct sensitivity exists between roots of different order and interference with various cellular processes is responsible for the effects of Ni on roots. We also show that Ni-treated roots have several auxin-related phenotypes. (authors)

Root caries prevention via sodium fluoride, chlorhexidine and silver diamine fluoride in vitro.

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Göstemeyer, Gerd; Kohls, Anna; Paris, Sebastian; Schwendicke, Falk

2018-01-31

Uncertainty exists as to how to best prevent root caries development. The aim of the present study was to compare sodium fluoride (NaF), chlorhexidine (CHX) and silver diamine fluoride (SDF) varnishes (V) and rinses (R) regarding their caries preventive effect in an artificial caries biofilm model. 140 bovine root dentin samples were cut, polished and embedded. Samples were allocated to seven treatment groups (n = 20/group): Four varnishes (applied once prior biofilm challenge): 38% SDF (SDFV), 35% CHX-varnish (CHXV), 22,600 ppm NaF-varnish (NaFV), placebo-varnish (PV); two rinses (applied once daily during biofilm challenge): 500 ppm NaF solution (NaFR), 0.1% CHX solution (CHXR); one untreated group. Caries was induced in a multi-station, continuous-culture Lactobacillus rhamnosus GG (LGG) biofilm model. Bacteria were inoculated 1 × daily, while 2% sucrose was supplied 8 ×/day followed by artificial saliva for 10 min. After 12 days, mineral loss (ΔZ) was measured in the effect area and adjacent to the varnished areas. Bacterial counts were assessed on de-Man-Rogosa-Sharpe agar. ΔZ was significantly lower in the NaFR group compared with all other groups. Varnishes did not significantly prevent mineral loss in adjacent areas. None of the agents had a significant antimicrobial effect on LGG. Regular fluoride rinses showed highest root caries-preventive effect.

Nursery temperature as a factor in root elongation of ponderosa pine seedlings

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Gilbert H. Schubert; Frank J. Baron

1965-01-01

Greenhouse and nursery studies suggest that graphs of "effective" day and night temperatures provide a convenient method to compare nursery sites and to evaluate the effects of temperature on seedling root growth. Comparisons of root response under different natural temperature regimes should provide inforrnation use ful 'for the production of higher...

Factors affecting root curvature of mandibular first molar

International Nuclear Information System (INIS)

Choi, Hang Moon; Yi, Won Jin; Heo, Min Suk; Kim, Jung Hwa; Choi, Soon Chul; Park, Tae Won

2006-01-01

To find the cause of root curvature by use of panoramic and lateral cephalometric radiograph. Twenty six 1st graders whose mandibular 1st molars just emerged into the mouth were selected. Panoramic and lateral cephalometric radiograph were taken at grade 1 and 6, longitudinally. In cephalometric radio graph, mandibular plane angle, ramus-occlusal place angle, gonial angle, and gonion-gnathion distance(Go-Gn distance) were measured. In panoramic radiograph, elongated root length and root angle were measured by means of digital subtraction radiography. Occlusal plane-tooth axis angle was measured, too. Pearson correlations were used to evaluate the relationships between root curvature and elongated length and longitudinal variations of all variables. Multiple regression equation using related variables was computed. The pearson correlation coefficient between curved angle and longitudinal variations of occlusal plane-tooth axis angle and ramus-occlusal plane angle was 0.350 and 0.401, respectively (p 1 +0.745X 2 (Y: root angle, X 1 : variation of occlusal plane-tooth axis angle, X 2 : variation of ramus-occlusal plane angle). It was suspected that the reasons of root curvature were change of tooth axis caused by contact with 2nd deciduous tooth and amount of mesial and superior movement related to change of occlusal plane

Brassinosteroid signaling-dependent root responses to prolonged elevated ambient temperature.

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Martins, Sara; Montiel-Jorda, Alvaro; Cayrel, Anne; Huguet, Stéphanie; Roux, Christine Paysant-Le; Ljung, Karin; Vert, Grégory

2017-08-21

Due to their sessile nature, plants have to cope with and adjust to their fluctuating environment. Temperature elevation stimulates the growth of Arabidopsis aerial parts. This process is mediated by increased biosynthesis of the growth-promoting hormone auxin. How plant roots respond to elevated ambient temperature is however still elusive. Here we present strong evidence that temperature elevation impinges on brassinosteroid hormone signaling to alter root growth. We show that elevated temperature leads to increased root elongation, independently of auxin or factors known to drive temperature-mediated shoot growth. We further demonstrate that brassinosteroid signaling regulates root responses to elevated ambient temperature. Increased growth temperature specifically impacts on the level of the brassinosteroid receptor BRI1 to downregulate brassinosteroid signaling and mediate root elongation. Our results establish that BRI1 integrates temperature and brassinosteroid signaling to regulate root growth upon long-term changes in environmental conditions associated with global warming.Moderate heat stimulates the growth of Arabidopsis shoots in an auxin-dependent manner. Here, Martins et al. show that elevated ambient temperature modifies root growth by reducing the BRI1 brassinosteroid-receptor protein level and downregulating brassinosteroid signaling.

Salicylic acid prevents Trichoderma harzianum from entering the vascular system of roots.

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Alonso-Ramírez, Ana; Poveda, Jorge; Martín, Ignacio; Hermosa, Rosa; Monte, Enrique; Nicolás, Carlos

2014-10-01

Trichoderma is a soil-borne fungal genus that includes species with a significant impact on agriculture and industrial processes. Some Trichoderma strains exert beneficial effects in plants through root colonization, although little is known about how this interaction takes place. To better understand this process, the root colonization of wild-type Arabidopsis and the salicylic acid (SA)-impaired mutant sid2 by a green fluorescent protein (GFP)-marked Trichoderma harzianum strain was followed under confocal microscopy. Trichoderma harzianum GFP22 was able to penetrate the vascular tissue of the sid2 mutant because of the absence of callose deposition in the cell wall of root cells. In addition, a higher colonization of sid2 roots by GFP22 compared with that in Arabidopsis wild-type roots was detected by real-time polymerase chain reaction. These results, together with differences in the expression levels of plant defence genes in the roots of both interactions, support a key role for SA in Trichoderma early root colonization stages. We observed that, without the support of SA, plants were unable to prevent the arrival of the fungus in the vascular system and its spread into aerial parts, leading to later collapse. © 2014 BSPP AND JOHN WILEY & SONS LTD.

Root tips moving through soil

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Curlango-Rivera, Gilberto

2011-01-01

Root elongation occurs by the generation of new cells from meristematic tissue within the apical 1–2 mm region of root tips. Therefore penetration of the soil environment is carried out by newly synthesized plant tissue, whose cells are inherently vulnerable to invasion by pathogens. This conundrum, on its face, would seem to reflect an intolerable risk to the successful establishment of root systems needed for plant life. Yet root tip regions housing the meristematic tissues repeatedly have been found to be free of microbial infection and colonization. Even when spore germination, chemotaxis, and/or growth of pathogens are stimulated by signals from the root tip, the underlying root tissue can escape invasion. Recent insights into the functions of root border cells, and the regulation of their production by transient exposure to external signals, may shed light on long-standing observations. PMID:21455030

Functional, electrophysiological recoveries of rats with sciatic nerve lesions following transplantation of elongated DRG cells.

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Dayawansa, Samantha; Zhang, Jun; Shih, Chung-Hsuan; Tharakan, Binu; Huang, Jason H

2016-04-01

Functional data are essential when confirming the efficacy of elongated dorsal root ganglia (DRG) cells as a substitute for autografting. We present the quantitative functional motor, electrophysiological findings of engineered DRG recipients for the first time. Elongated DRG neurons and autografts were transplanted to bridge 1-cm sciatic nerve lesions of Sprague Dawley (SD) rats. Motor recoveries of elongated DRG recipients (n=9), autograft recipients (n=9), unrepaired rats (n=9) and intact rats (n=6) were investigated using the angle board challenge test following 16 weeks of recovery. Electrophysiology studies were conducted to assess the functional recovery at 16 weeks. In addition, elongated DRGs were subjected to histology assessments. At threshold levels (35° angle) of the angle board challenge test, the autograft recipients', DRG recipients' and unrepaired group's performances were equal to each other and were less than the intact group (pDRG recipients' performance was similar to both the intact group and the autograft nerve recipients, and was better (pDRG constructs had intact signal transmission when recorded over the lesion, while the unrepaired rats did not. It was observed that elongated DRG neurons closely resembled an autograft during histological assessments. Performances of autograft and elongated DRG construct recipients were similar. Elongated DRG neurons should be further investigated as a substitute for autografting.

Cadmium and copper change root growth and morphology of Pinus pinea and Pinus pinaster seedlings

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Arduini, I.; Onnis, A. (Dipart. di Agronomia e Gestione dell' Agro-Ecosistema, Univ. degli Studi Pisa, Pisa (Italy)); Boldbold, D.L. (Forstbotanishces Institut, Univ. Goettingen, Goettingen (Germany))

1994-01-01

Heavy metal loads in forest soils have been increasing over time due to atmospheric inputs. Accumulation in the upper soil layers could affect establishment of seedlings and forest regeneration. Mediterranean species show a high initial root development, allowing seedlings to reach the moisture of deeper soil layers. In the present work seedlings of stone pine (Pinus pinea L.) and maritime pine (Pinus pinaster Ait.), were grown in culture solution supplied with 0.0, 0.1, 1 or 5 [mu]M CdSO[sub 4] or with 1 [mu]M CdSO[sub 4] and 1 [mu]M CuSO[sub 4] combined. In both species tap-root elongation was drastically reduced in the 5 [mu]M Cd[sup 2+] and in the (Cd[sup 2+] - Cu[sup 2+]) treatments. A supply of 0.1 or 1 [mu]M Cd[sup 2+] however, enhanced root elongation in Pinus pinea without significantly influencing root elongation in Pinus pinaster. In both species the root density (weight per unit length) and the width of the cortex increased in response to Cd[sup 2+] exposure. In Pinus pinaster the mitotic index decreased at the higher Cd[sup 2+] concentrations and when Cd[sup 2+] and Cu[sup 2+] were combined. The data suggest that cell elongation is more sensitive to Cd[sup 2+] than cell division. The number and length of the lateral roots were also affected by Cd[sup 2+] treatment to a higher degree in Pinus pinaster than in Pinus pinea, reflecting the different Cd-tolerance of the two species. (au)

Morphometric analysis of epidermal differentiation in primary roots of Zea mays

Science.gov (United States)

Moore, R.; Smith, H. S.

1990-01-01

Epidermal differentiation in primary roots of Zea mays was divided into six cell types based on cellular shape and cytoplasmic appearance. These six cell types are: 1) apical protoderm, located at the tip of the root pole and characterized by periclinally flattened cells; 2) cuboidal protoderm, located approximately 230 microns from the root pole and characterized by cuboidal cells; 3) tabular epidermis, located approximately 450 microns from the root pole and characterized by anticlinally flattened cells; 4) cuboidal epidermis, located approximately 900 microns from the root pole and characterized by cuboidal cells having numerous small vacuoles; 5) vacuolate cuboidal epidermis, located approximately 1,500 microns from the root pole and characterized by cuboidal cells containing several large vacuoles; and 6) columnar epidermis, located approximately 2,200 microns from the root pole (i.e., at the beginning of the zone of elongation) and characterized by elongated cells. We also used stereology to quantify the cellular changes associated with epidermal differentiation. The quiescent center and the apical protoderm have significantly different ultrastructures. The relative volume of dictyosomes increases dramatically during the early stages of epidermal differentiation. This increase correlates inversely with the amount of coverage provided by the root cap and mucilage.

Contributions of roots and rootstocks to sustainable, intensified crop production.

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Gregory, Peter J; Atkinson, Christopher J; Bengough, A Glyn; Else, Mark A; Fernández-Fernández, Felicidad; Harrison, Richard J; Schmidt, Sonja

2013-03-01

Sustainable intensification is seen as the main route for meeting the world's increasing demands for food and fibre. As demands mount for greater efficiency in the use of resources to achieve this goal, so the focus on roots and rootstocks and their role in acquiring water and nutrients, and overcoming pests and pathogens, is increasing. The purpose of this review is to explore some of the ways in which understanding root systems and their interactions with soils could contribute to the development of more sustainable systems of intensive production. Physical interactions with soil particles limit root growth if soils are dense, but root-soil contact is essential for optimal growth and uptake of water and nutrients. X-ray microtomography demonstrated that maize roots elongated more rapidly with increasing root-soil contact, as long as mechanical impedance was not limiting root elongation, while lupin was less sensitive to changes in root-soil contact. In addition to selecting for root architecture and rhizosphere properties, the growth of many plants in cultivated systems is profoundly affected by selection of an appropriate rootstock. Several mechanisms for scion control by rootstocks have been suggested, but the causal signals are still uncertain and may differ between crop species. Linkage map locations for quantitative trait loci for disease resistance and other traits of interest in rootstock breeding are becoming available. Designing root systems and rootstocks for specific environments is becoming a feasible target.

Gibberellin biosynthesis and signal transduction is essential for internode elongation in deepwater rice.

Science.gov (United States)

Ayano, Madoka; Kani, Takahiro; Kojima, Mikiko; Sakakibara, Hitoshi; Kitaoka, Takuya; Kuroha, Takeshi; Angeles-Shim, Rosalyn B; Kitano, Hidemi; Nagai, Keisuke; Ashikari, Motoyuki

2014-10-01

Under flooded conditions, the leaves and internodes of deepwater rice can elongate above the water surface to capture oxygen and prevent drowning. Our previous studies showed that three major quantitative trait loci (QTL) regulate deepwater-dependent internode elongation in deepwater rice. In this study, we investigated the age-dependent internode elongation in deepwater rice. We also investigated the relationship between deepwater-dependent internode elongation and the phytohormone gibberellin (GA) by physiological and genetic approach using a QTL pyramiding line (NIL-1 + 3 + 12). Deepwater rice did not show internode elongation before the sixth leaf stage under deepwater condition. Additionally, deepwater-dependent internode elongation occurred on the sixth and seventh internodes during the sixth leaf stage. These results indicate that deepwater rice could not start internode elongation until the sixth leaf stage. Ultra-performance liquid chromatography tandem mass-spectrometry (UPLC-MS/MS) method for the phytohormone contents showed a deepwater-dependent GA1 and GA4 accumulation in deepwater rice. Additionally, a GA inhibitor abolished deepwater-dependent internode elongation in deepwater rice. On the contrary, GA feeding mimicked internode elongation under ordinary growth conditions. However, mutations in GA biosynthesis and signal transduction genes blocked deepwater-dependent internode elongation. These data suggested that GA biosynthesis and signal transduction are essential for deepwater-dependent internode elongation in deepwater rice. © 2014 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.

The Root Transition Zone: A Hot Spot for Signal Crosstalk.

Science.gov (United States)

Kong, Xiangpei; Liu, Guangchao; Liu, Jiajia; Ding, Zhaojun

2018-05-01

The root transition zone (TZ), located between the apical meristem and basal elongation region, has a unique role in root growth and development. The root TZ is not only the active site for hormone crosstalk, but also the perception site for various environmental cues, such as aluminum (Al) stress and low phosphate (Pi) stress. We propose that the root TZ is a hot spot for the integration of diverse inputs from endogenous (hormonal) and exogenous (sensorial) stimuli to control root growth. Copyright © 2018 Elsevier Ltd. All rights reserved.

The Effect of Root Coating with Titanium on Prevention of Root Resorption in Avulsed Teeth: An Animal Study

Science.gov (United States)

Heydari, Azar; Tahmasbi, Soodeh; Badiee, Mohammadreza; Izadi, SeyedSadra; Mashhadi Abbas, Fatemeh; Mokhtari, Sepideh

2016-01-01

Introduction: Tooth avulsion is a real dental emergency. If immediate replantation is not performed, the avulsed tooth may be lost due to inflammatory or replacement resorption. This animal study aimed to evaluate the bone response to the titanium coating of the root surface as an artificial barrier, and prevention of resorption of avulsed teeth. Methods and Materials: This experimental study was conducted on four male dogs. The dogs were randomly divided into two groups for assessment at two and eight weeks. Four teeth were extracted in each animal. The root surfaces of the test group were coated with a titanium layer using the Electron Beam Deposition system. After 24 h, replantation of the teeth was performed. Two animals were sacrificed after two weeks and the remaining dogs were killed after eight weeks. The presence of inflammation, inflammatory resorption, replacement resorption, periodontal regeneration, periapical granuloma and ankylosis were evaluated through histological analyses. Results: Inflammatory root resorption was not present in any tooth except one tooth in the coated group after eight weeks. Replacement resorption was noted just in three of the non-coated teeth after two weeks and two teeth after eight weeks. The McNemar's test revealed that the frequency of replacement resorption in the non-coated group was significantly higher than the coated group (P=0.031). Conclusion: Based on the results of this study, it seems that coating the root surfaces of avulsed teeth with titanium may control the replacement root resorption. PMID:27790261

Inhibition of primary roots and stimulation of lateral root development in Arabidopsis thaliana by the rhizobacterium Serratia marcescens 90-166 is through both auxin-dependent and -independent signaling pathways.

Science.gov (United States)

Shi, Chun-Lin; Park, Hyo-Bee; Lee, Jong Suk; Ryu, Sangryeol; Ryu, Choong-Min

2010-03-01

The rhizobacterium Serratia marcescens strain 90-166 was previously reported to promote plant growth and induce resistance in Arabidopsis thaliana. In this study, the influence of strain 90-166 on root development was studied in vitro. We observed inhibition of primary root elongation, enhanced lateral root emergence, and early emergence of second order lateral roots after inoculation with strain 90-166 at a certain distance from the root. Using the DR5::GUS transgenic A. thaliana plant and an auxin transport inhibitor, N-1-naphthylphthalamic acid, the altered root development was still elicited by strain 90-166, indicating that this was not a result of changes in plant auxin levels. Intriguingly, indole-3-acetic acid, a major auxin chemical, was only identified just above the detection limit in liquid culture of strain 90-166 using liquid chromatography-mass spectrometry. Focusing on bacterial determinants of the root alterations, we found that primary root elongation was inhibited in seedlings treated with cell supernatant (secreted compounds), while lateral root formation was induced in seedlings treated with lysate supernatant (intracellular compounds). Further study revealed that the alteration of root development elicited by strain 90-166 involved the jasmonate, ethylene, and salicylic acid signaling pathways. Collectively, our results suggest that strain 90-166 can contribute to plant root development via multiple signaling pathways.

Can early aortic root surgery prevent further aortic dissection in Marfan syndrome?

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Shimizu, Hideyuki; Kasahara, Hirofumi; Nemoto, Atsushi; Yamabe, Kentaro; Ueda, Toshihiko; Yozu, Ryohei

2012-02-01

We reviewed 50 patients with Marfan syndrome who underwent surgery for aortic root pathologies comprising a root aneurysm without (n = 25; group A) and with (n = 25; group B) dissection. Aortic root repair included Bentall (n = 37) and valve-sparing (n = 13) procedures. Hospital mortality was 4.0%. Twenty-two patients required 36 repeat surgeries on the distal aorta. The main indication for re-intervention was the dilation of the false lumen. In group A, the distal aorta was stable for up to 7 years, but new dissection developed in 5 (33.3%) of the 15 patients who were followed up for >7 years after the root repair. Actuarial survival including operative mortality was 88.1 and 65.0% at 10 and 20 years, respectively; groups A and B did not significantly differ. Rates of freedom from all-cause death, new dissection or repeated aortic surgery were 60.1, 44.5 and 26.0% at 5, 10 and 15 years, respectively. Group A was significantly better than group B. Prophylactic aortic root repair apparently reduces the likelihood of overall adverse events, but it cannot guarantee the prevention of further aortic dissection. A multidisciplinary approach is needed for patients with Marfan syndrome.

Regulation of Arabidopsis root development by nitrate availability.

Science.gov (United States)

Zhang, H; Forde, B G

2000-01-01

When the root systems of many plant species are exposed to a localized source of nitrate (NO3- they respond by proliferating their lateral roots to colonize the nutrient-rich zone. This study reviews recent work with Arabidopsis thaliana in which molecular genetic approaches are being used to try to understand the physiological and genetic basis for this response. These studies have led to the conclusion that there are two distinct pathways by which NO3- modulates root branching in Arabidopsis. On the one hand, meristematic activity in lateral root tips is stimulated by direct contact with an enriched source of NO3- (the localized stimulatory effect). On the other, a critical stage in the development of the lateral root (just after its emergence from the primary root) is highly susceptible to inhibition by a systemic signal that is related to the amount of NO3- absorbed by the plant (the systemic inhibitory effect). Evidence has been obtained that the localized stimulatory effect is a direct effect of the NO3- ion itself rather than a nutritional effect. A NO3(-)-inducible MADS-box gene (ANR1) has been identified which encodes a component of the signal transduction pathway linking the external NO3- supply to the increased rate of lateral root elongation. Experiments using auxin-resistant mutants have provided evidence for an overlap between the auxin and NO3- response pathways in the control of lateral root elongation. The systemic inhibitory effect, which does not affect lateral root initiation but delays the activation of the lateral root meristem, appears to be positively correlated with the N status of the plant and is postulated to involve a phloem-mediated signal from the shoot.

A pollen-specific RALF from tomato that regulates pollen tube elongation.

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Covey, Paul A; Subbaiah, Chalivendra C; Parsons, Ronald L; Pearce, Gregory; Lay, Fung T; Anderson, Marilyn A; Ryan, Clarence A; Bedinger, Patricia A

2010-06-01

Rapid Alkalinization Factors (RALFs) are plant peptides that rapidly increase the pH of plant suspension cell culture medium and inhibit root growth. A pollen-specific tomato (Solanum lycopersicum) RALF (SlPRALF) has been identified. The SlPRALF gene encodes a preproprotein that appears to be processed and released from the pollen tube as an active peptide. A synthetic SlPRALF peptide based on the putative active peptide did not affect pollen hydration or viability but inhibited the elongation of normal pollen tubes in an in vitro growth system. Inhibitory effects of SlPRALF were detectable at concentrations as low as 10 nm, and complete inhibition was observed at 1 mum peptide. At least 10-fold higher levels of alkSlPRALF, which lacks disulfide bonds, were required to see similar effects. A greater effect of peptide was observed in low-pH-buffered medium. Inhibition of pollen tube elongation was reversible if peptide was removed within 15 min of exposure. Addition of 100 nm SlPRALF to actively growing pollen tubes inhibited further elongation until tubes were 40 to 60 mum in length, after which pollen tubes became resistant to the peptide. The onset of resistance correlated with the timing of the exit of the male germ unit from the pollen grain into the tube. Thus, exogenous SlPRALF acts as a negative regulator of pollen tube elongation within a specific developmental window.

L-Cysteine inhibits root elongation through auxin/PLETHORA and SCR/SHR pathway in Arabidopsis thaliana.

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Wang, Zhen; Mao, Jie-Li; Zhao, Ying-Jun; Li, Chuan-You; Xiang, Cheng-Bin

2015-02-01

L-Cysteine plays a prominent role in sulfur metabolism of plants. However, its role in root development is largely unknown. Here, we report that L-cysteine reduces primary root growth in a dosage-dependent manner. Elevating cellular L-cysteine level by exposing Arabidopsis thaliana seedlings to high L-cysteine, buthionine sulphoximine, or O-acetylserine leads to altered auxin maximum in root tips, the expression of quiescent center cell marker as well as the decrease of the auxin carriers PIN1, PIN2, PIN3, and PIN7 of primary roots. We also show that high L-cysteine significantly reduces the protein level of two sets of stem cell specific transcription factors PLETHORA1/2 and SCR/SHR. However, L-cysteine does not downregulate the transcript level of PINs, PLTs, or SCR/SHR, suggesting that an uncharacterized post-transcriptional mechanism may regulate the accumulation of PIN, PLT, and SCR/SHR proteins and auxin transport in the root tips. These results suggest that endogenous L-cysteine level acts to maintain root stem cell niche by regulating basal- and auxin-induced expression of PLT1/2 and SCR/SHR. L-Cysteine may serve as a link between sulfate assimilation and auxin in regulating root growth. © 2014 Institute of Botany, Chinese Academy of Sciences.

Ethylene Inhibits Cell Proliferation of the Arabidopsis Root Meristem1[OPEN

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Street, Ian H.; Aman, Sitwat; Zubo, Yan; Ramzan, Aleena; Wang, Xiaomin; Shakeel, Samina N.; Kieber, Joseph J.; Schaller, G. Eric

2015-01-01

The root system of plants plays a critical role in plant growth and survival, with root growth being dependent on both cell proliferation and cell elongation. Multiple phytohormones interact to control root growth, including ethylene, which is primarily known for its role in controlling root cell elongation. We find that ethylene also negatively regulates cell proliferation at the root meristem of Arabidopsis (Arabidopsis thaliana). Genetic analysis indicates that the inhibition of cell proliferation involves two pathways operating downstream of the ethylene receptors. The major pathway is the canonical ethylene signal transduction pathway that incorporates CONSTITUTIVE TRIPLE RESPONSE1, ETHYLENE INSENSITIVE2, and the ETHYLENE INSENSITIVE3 family of transcription factors. The secondary pathway is a phosphorelay based on genetic analysis of receptor histidine kinase activity and mutants involving the type B response regulators. Analysis of ethylene-dependent gene expression and genetic analysis supports SHORT HYPOCOTYL2, a repressor of auxin signaling, as one mediator of the ethylene response and furthermore, indicates that SHORT HYPOCOTYL2 is a point of convergence for both ethylene and cytokinin in negatively regulating cell proliferation. Additional analysis indicates that ethylene signaling contributes but is not required for cytokinin to inhibit activity of the root meristem. These results identify key elements, along with points of cross talk with cytokinin and auxin, by which ethylene negatively regulates cell proliferation at the root apical meristem. PMID:26149574

Europium Uptake and Partitioning in Oat (Avena sativa) Roots as studied By Laser-Induced Fluorescence Spectroscopy and Confocal Microscopy Profiling Technique

International Nuclear Information System (INIS)

Fellows, Robert J.; Wang, Zheming; Ainsworth, Calvin C.

2003-01-01

The uptake of Eu3+ by elongating oat plant roots was studied by fluorescence spectroscopy, fluorescence lifetime measurement, as well as laser excitation time-resolved confocal fluorescence profiling technique. The results of this work indicated that the initial uptake of Eu(III) by oat root was most evident within the apical meristem of the root just proximal to the root cap. Distribution of assimilated Eu(III) within the roots differentiation and elongation zone was non-uniform. Higher concentrations were observed within the vascular cylinder, specifically in the phloem and developing xylem parenchyma. Elevated levels of the metal were also observed in the root hairs of the mature root. The concentration of assimilated Eu3+ dropped sharply from the apical meristem to the differentiation and elongation zone and then gradually decreased as the distance from the root cap increased. Fluorescence spectroscopic characteristics of the assimilated Eu3+ suggested that the Eu3+ exists a s inner-sphere mononuclear complexes inside the root. This work has also demonstrated the effectiveness of a time-resolved Eu3+ fluorescence spectroscopy and confocal fluorescence profiling techniques for the in vivo, real-time study of metal[Eu3+] accumulation by a functioning intact plant root. This approach can prove valuable for basic and applied studies in plant nutrition and environmental uptake of actinide radionuclides

Changes in hormonal balance and meristematic activity in primary root tips on the slowly rotating clinostat and their effect on the development of the rapeseed root system.

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Aarrouf, J; Schoevaert, D; Maldiney, R; Perbal, G

1999-04-01

The morphometry of the root system, the meristematic activity and the level of indole-3-acetic acid (IAA), abscisic acid (ABA) and zeatin in the primary root tips of rapeseed seedlings were analyzed as functions of time on a slowly rotating clinostat (1 rpm) or in the vertical controls (1 rpm). The fresh weight of the root system was 30% higher throughout the growth period (25 days) in clinorotated seedlings. Morphometric analysis showed that the increase in biomass on the clinostat was due to greater primary root growth, earlier initiation and greater elongation of the secondary roots, which could be observed even in 5-day-old seedlings. However, after 15 days, the growth of the primary root slowed on the clinostat, whereas secondary roots still grew faster in clinorotated plants than in the controls. At this time, the secondary roots began to be initiated closer to the root tip on the clinostat than in the control. Analysis of the meristematic activity and determination of the levels in IAA, ABA and zeatin in the primary root tips demonstrated that after 5 days on the clinostat, the increased length of the primary root could be the consequence of higher meristematic activity and coincided with an increase in both IAA and ABA concentrations. After 15 days on the clinostat, a marked increase in IAA, ABA and zeatin, which probably reached supraoptimal levels, seems to cause a progressive disturbance of the meristematic cells, during a decrease of primary root growth between 15 and 25 days. These modifications in the hormonal balance and the perturbation of the meristematic activity on the clinostat were followed by a loss of apical dominance, which was responsible for the early initiation of secondary roots, the greater elongation of the root system and the emergence of the lateral roots near the tip of the primary root.

Pharmacognostic Investigation of Clerodendrum phlomidis Linn. f. Root

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Dinesh Kumar

2014-05-01

Full Text Available The present study was aimed to perform the pharmacognostic evaluation of Clerodendrum phlomidis Linn. f. root in terms of organoleptic, fluorescence analysis, macro-microscopy and physicochemical parameters.The characteristic macroscopic study showed that the root consists of 7-15 cm long, 0.2 -3.0 cm thick pieces which are cylindrical, tough and yellowish-brown externally, with hard fracture and slightly astringent taste. The main microscopic characters of the root show exfoliating cork, having10-15 rows of tangentially elongated, thick-walled cells. Cortex consists of round to oval parenchymatous cells, a few containing rhomboid shaped calcium oxalate crystals. Endodermis consists of 3- 4 layers of non-lignified, thick-walled rounded parenchymatous cells followed by a single pericyclic layer. Phloem consists of isodiametric, thin-walled, parenchymatous cells whereas xylem contains lignified pitted vessels. Medullary rays consisting of biseriate layer of lignified and radially elongated parenchymatous cells is narrower in the xylem region during wider in the phloem region. The physicochemical analysis of the root, i.e., total ash, water-soluble ash, sulphated ash are 7.8, 0.9 and 10.3 (% w/w respectively. Further successive extraction of the root powder with petroleum ether, chloroform, alcohol, water yielded 2.2, 2.4, 12.4 and 9.6 (% w/wextracts respectively. Fluorescence study imparted characteristic colours to the root powder when observed under visible, short and long wavelength light. Various pharmacognostic parameters evaluated in this study helps inbotanical identification and standardization of Clerodendrum phlomidis L. root part in crude form and provide the authentic data for the researchers and scientists involved in carrying out further research on this plant part.

Elongation-related functions of LEAFY COTYLEDON1 during the development of Arabidopsis thaliana.

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Junker, Astrid; Mönke, Gudrun; Rutten, Twan; Keilwagen, Jens; Seifert, Michael; Thi, Tuyet Minh Nguyen; Renou, Jean-Pierre; Balzergue, Sandrine; Viehöver, Prisca; Hähnel, Urs; Ludwig-Müller, Jutta; Altschmied, Lothar; Conrad, Udo; Weisshaar, Bernd; Bäumlein, Helmut

2012-08-01

The transcription factor LEAFY COTYLEDON1 (LEC1) controls aspects of early embryogenesis and seed maturation in Arabidopsis thaliana. To identify components of the LEC1 regulon, transgenic plants were derived in which LEC1 expression was inducible by dexamethasone treatment. The cotyledon-like leaves and swollen root tips developed by these plants contained seed-storage compounds and resemble the phenotypes produced by increased auxin levels. In agreement with this, LEC1 was found to mediate up-regulation of the auxin synthesis gene YUCCA10. Auxin accumulated primarily in the elongation zone at the root-hypocotyl junction (collet). This accumulation correlates with hypocotyl growth, which is either inhibited in LEC1-induced embryonic seedlings or stimulated in the LEC1-induced long-hypocotyl phenotype, therefore resembling etiolated seedlings. Chromatin immunoprecipitation analysis revealed a number of phytohormone- and elongation-related genes among the putative LEC1 target genes. LEC1 appears to be an integrator of various regulatory events, involving the transcription factor itself as well as light and hormone signalling, especially during somatic and early zygotic embryogenesis. Furthermore, the data suggest non-embryonic functions for LEC1 during post-germinative etiolation. © 2012 The Authors. The Plant Journal © 2012 Blackwell Publishing Ltd.

Comparative effects of auxin and abscisic acid on growth, hydrogen ion efflux and gravitropism in primary roots of maize

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Evans, M. L.; Mulkey, T. J.

1984-01-01

In order to test the idea that auxin action on root growth may be mediated by H(+) movement, the correlation of auxin action on growth and H(+) movement in roots was examined along with changes in H(+) efflux patterns associated with the asymmetric growth which occurs during gravitropism. The effects of indoleacetic acid (IAA) and abscisic acid (AbA) on growth, H(+) secretion, and gravitropism in roots were compared. Results show a close correlation existent between H(+) efflux and growth in maize roots. In intact roots there is strong H(+) efflux from the elongation zone. Growth-promoting concentrations of IAA stimulate H(+) efflux. During gravitropism the H(+) efflux from the elongation zone becomes asymmetric; the evidence indicates that auxin redistribution contributes to the development of acid efflux asymmetry. That AbA stimulates root growth is reflected in its ability to stimulate H(+) efflux from apical root segments.

The role of auxin and cytokinin signalling in specifying the root architecture of Arabidopsis thaliana

KAUST Repository

Muraro, Daniele

2013-01-01

Auxin and cytokinin are key hormonal signals that control the cellular architecture of the primary root and the initiation of new lateral root organs in the plant Arabidopsis thaliana. Both developmental processes are regulated by cross-talk between these hormones and their signalling pathways. In this paper, sub-cellular and multi-cellular mathematical models are developed to investigate how interactions between auxin and cytokinin influence the size and location of regions of division and differentiation within the primary root, and describe how their cross-regulation may cause periodic branching of lateral roots. We show how their joint activity may influence tissue-specific oscillations in gene expression, as shown in Moreno-Risueno et al. (2010) and commented upon in Traas and Vernoux (2010), and we propose mechanisms that may generate synchronisation of such periodic behaviours inside a cell and with its neighbours. Using a multi-cellular model, we also analyse the roles of cytokinin and auxin in specifying the three main regions of the primary root (elongation, transition and division zones), our simulation results being in good agreement with independent experimental observations. We then use our model to generate testable predictions concerning the effect of varying the concentrations of the auxin efflux transporters on the sizes of the different root regions. In particular, we predict that over-expression of the transporters will generate a longer root with a longer elongation zone and a smaller division zone than that of a wild type root. This root will contain fewer cells than its wild type counterpart. We conclude that our model can provide a useful tool for investigating the response of cell division and elongation to perturbations in hormonal signalling. © 2012 Elsevier Ltd.

The Ca2+ pump inhibitor, thapsigargin, inhibits root gravitropism in Arabidopsis thaliana

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DANIELA C URBINA

2006-01-01

Full Text Available Thapsigargin, a specific inhibitor of most animal intracellular SERCA-type Ca2+ pumps present in the sarcoplasmic/endoplasmic reticulum, was originally isolated from the roots of the Mediterranean plant Thapsia gargancia L. Here, we demonstrate that this root-derived compound is capable of altering root gravitropism in Arabidopsis thaliana. Thapsigargin concentrations as low as 0.1 µM alter root gravitropism whereas under similar conditions cyclopiazonic acid does not. Furthermore, a fluorescently conjugated thapsigargin (BODIPY FL thapsigargin suggests that target sites for thapsigargin are located in intracellular organelles in the root distal elongation zone and the root cap, regions known to regulate root gravitropism

The MEDIATOR genes MED12 and MED13 control Arabidopsis root system configuration influencing sugar and auxin responses.

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Raya-González, Javier; López-Bucio, Jesús Salvador; Prado-Rodríguez, José Carlos; Ruiz-Herrera, León Francisco; Guevara-García, Ángel Arturo; López-Bucio, José

2017-09-01

Arabidopsis med12 and med13 mutants exhibit shoot and root phenotypes related to an altered auxin homeostasis. Sucrose supplementation reactivates both cell division and elongation in primary roots as well as auxin-responsive and stem cell niche gene expression in these mutants. An analysis of primary root growth of WT, med12, aux1-7 and med12 aux1 single and double mutants in response to sucrose and/or N-1-naphthylphthalamic acid (NPA) placed MED12 upstream of auxin transport for the sugar modulation of root growth. The MEDIATOR (MED) complex plays diverse functions in plant development, hormone signaling and biotic and abiotic stress tolerance through coordination of transcription. Here, we performed genetic, developmental, molecular and pharmacological analyses to characterize the role of MED12 and MED13 on the configuration of root architecture and its relationship with auxin and sugar responses. Arabidopsis med12 and med13 single mutants exhibit shoot and root phenotypes consistent with altered auxin homeostasis including altered primary root growth, lateral root development, and root hair elongation. MED12 and MED13 were required for activation of cell division and elongation in primary roots, as well as auxin-responsive and stem cell niche gene expression. Remarkably, most of these mutant phenotypes were rescued by supplying sucrose to the growth medium. The growth response of primary roots of WT, med12, aux1-7 and med12 aux1 single and double mutants to sucrose and application of auxin transport inhibitor N-1-naphthylphthalamic acid (NPA) revealed the correlation of med12 phenotype with the activity of the auxin intake permease and suggests that MED12 acts upstream of AUX1 in the root growth response to sugar. These data provide compelling evidence that MEDIATOR links sugar sensing to auxin transport and distribution during root morphogenesis.

A 3D digital atlas of the Nicotiana tabacum root tip and its use to investigate changes in the root apical meristem induced by the Agrobacterium 6b oncogene.

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Pasternak, Taras; Haser, Thomas; Falk, Thorsten; Ronneberger, Olaf; Palme, Klaus; Otten, Léon

2017-10-01

Using the intrinsic Root Coordinate System (iRoCS) Toolbox, a digital atlas at cellular resolution has been constructed for Nicotiana tabacum roots. Mitotic cells and cells labeled for DNA replication with 5-ethynyl-2'-deoxyuridine (EdU) were mapped. The results demonstrate that iRoCS analysis can be applied to roots that are thicker than those of Arabidopsis thaliana without histological sectioning. A three-dimensional (3-D) analysis of the root tip showed that tobacco roots undergo several irregular periclinal and tangential divisions. Irrespective of cell type, rapid cell elongation starts at the same distance from the quiescent center, however, boundaries between cell proliferation and transition domains are cell-type specific. The data support the existence of a transition domain in tobacco roots. Cell endoreduplication starts in the transition domain and continues into the elongation zone. The tobacco root map was subsequently used to analyse root organization changes caused by the inducible expression of the Agrobacterium 6b oncogene. In tobacco roots that express the 6b gene, the root apical meristem was shorter and radial cell growth was reduced, but the mitotic and DNA replication indexes were not affected. The epidermis of 6b-expressing roots produced less files and underwent abnormal periclinal divisions. The periclinal division leading to mature endodermis and cortex3 cell files was delayed. These findings define additional targets for future studies on the mode of action of the Agrobacterium 6b oncogene. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

Nitric oxide mediates strigolactone signaling in auxin and ethylene-sensitive lateral root formation in sunflower seedlings

OpenAIRE

Bharti, Niharika; Bhatla, Satish C

2015-01-01

Strigolactones (SLs) play significant role in shaping root architecture whereby auxin-SL crosstalk has been observed in SL-mediated responses of primary root elongation, lateral root formation and adventitious root (AR) initiation. Whereas GR24 (a synthetic strigolactone) inhibits LR and AR formation, the effect of SL biosynthesis inhibitor (fluridone) is just the opposite (root proliferation). Naphthylphthalamic acid (NPA) leads to LR proliferation but completely inhibits AR development. The...

Prevention of root caries with dentin adhesives.

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Grogono, A L; Mayo, J A

1994-04-01

This in vitro investigation determined the feasibility of using dentin adhesives to protect root surfaces against caries. The roots of 22 recently extracted human teeth were all painted with a protective lacquer leaving two unprotected small windows. On each specimen, one window (control) was left untreated and the other window (experimental) was treated using a dentin adhesive (Scotchbond Multi-Purpose). The roots were then immersed in an in vitro acetate/calcium/phosphate demineralization model at pH 4.3. After 70 days, the samples were removed and sectioned through the windows. The undecalcified ground sections were examined under transmitted and polarized light. Lesions characteristic of natural root caries were seen in the untreated control windows. No such lesions were apparent in the experimental windows. The results of this preliminary study suggest that dentin adhesives may provide protection against root caries.

Changes in root cap pH are required for the gravity response of the Arabidopsis root

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Fasano, J. M.; Swanson, S. J.; Blancaflor, E. B.; Dowd, P. E.; Kao, T. H.; Gilroy, S.

2001-01-01

Although the columella cells of the root cap have been identified as the site of gravity perception, the cellular events that mediate gravity signaling remain poorly understood. To determine if cytoplasmic and/or wall pH mediates the initial stages of root gravitropism, we combined a novel cell wall pH sensor (a cellulose binding domain peptide-Oregon green conjugate) and a cytoplasmic pH sensor (plants expressing pH-sensitive green fluorescent protein) to monitor pH dynamics throughout the graviresponding Arabidopsis root. The root cap apoplast acidified from pH 5.5 to 4.5 within 2 min of gravistimulation. Concomitantly, cytoplasmic pH increased in columella cells from 7.2 to 7.6 but was unchanged elsewhere in the root. These changes in cap pH preceded detectable tropic growth or growth-related pH changes in the elongation zone cell wall by 10 min. Altering the gravity-related columella cytoplasmic pH shift with caged protons delayed the gravitropic response. Together, these results suggest that alterations in root cap pH likely are involved in the initial events that mediate root gravity perception or signal transduction.

A Root-Colonizing Pseudomonad Lessens Stress Responses in Wheat Imposed by CuO Nanoparticles.

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Melanie Wright

Full Text Available Nanoparticle (NPs containing essential metals are being considered in formulations of fertilizers to boost plant nutrition in soils with low metal bioavailability. This paper addresses whether colonization of wheat roots by the bacterium, Pseudomonas chlororaphis O6 (PcO6, protected roots from the reduced elongation caused by CuO NPs. There was a trend for slightly elongated roots when seedlings with roots colonized by PcO6 were grown with CuO NPs; the density of bacterial cells on the root surface was not altered by the NPs. Accumulations of reactive oxygen species in the plant root cells caused by CuO NPs were little affected by root colonization. However, bacterial colonization did reduce the extent of expression of an array of genes associated with plant responses to stress induced by root exposure to CuO NPs. PcO6 colonization also reduced the levels of two important chelators of Cu ions, citric and malic acids, in the rhizosphere solution; presumably because these acids were used as nutrients for bacterial growth. There was a trend for lower levels of soluble Cu in the rhizosphere solution and reduced Cu loads in the true leaves with PcO6 colonization. These studies indicate that root colonization by bacterial cells modulates plant responses to contact with CuO NPs.

Anchorage failure of young trees in sandy soils is prevented by a rigid central part of the root system with various designs

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Danquechin Dorval, Antoine; Meredieu, Céline; Danjon, Frédéric

2016-01-01

Background and Aims Storms can cause huge damage to European forests. Even pole-stage trees with 80-cm rooting depth can topple. Therefore, good anchorage is needed for trees to survive and grow up from an early age. We hypothesized that root architecture is a predominant factor determining anchorage failure caused by strong winds. Methods We sampled 48 seeded or planted Pinus pinaster trees of similar aerial size from four stands damaged by a major storm 3 years before. The trees were gathered into three classes: undamaged, leaning and heavily toppled. After uprooting and 3D digitizing of their full root architectures, we computed the mechanical characteristics of the main components of the root system from our morphological measurements. Key Results Variability in root architecture was quite large. A large main taproot, either short and thick or long and thin, and guyed by a large volume of deep roots, was the major component that prevented stem leaning. Greater shallow root flexural stiffness mainly at the end of the zone of rapid taper on the windward side also prevented leaning. Toppling in less than 90-cm-deep soil was avoided in trees with a stocky taproots or with a very big leeward shallow root. Toppled trees also had a lower relative root biomass – stump excluded – than straight trees. Conclusions It was mainly the flexural stiffness of the central part of the root system that secured anchorage, preventing a weak displacement of the stump. The distal part of the longest taproot and attached deep roots may be the only parts of the root system contributing to anchorage through their maximum tensile load. Several designs provided good anchorage, depending partly on available soil depth. Pole-stage trees are in-between the juvenile phase when they fail by toppling and the mature phase when they fail by uprooting. PMID:27456136

DNA damage regulates alternative splicing through changes in POL II elongation

International Nuclear Information System (INIS)

Munoz, M.J.; Perez Santangelo, M.S.; De la Mata, M.; Kornblihtt, A.R.

2008-01-01

Many apoptotic genes are regulated via alternative splicing (AS) but little is known about the mechanisms controlling AS in stress situations derived from DNA damage. Here we show that ultraviolet (UV) radiation affects co-transcriptional, but not post transcriptional, AS through a systemic mechanism involving a CDK-9-dependent hyper phosphorylation of RNA polymerase II carboxy terminal domain (CTD) and a subsequent and unprecedented inhibition of transcriptional elongation, estimated in vivo and in real time by FRAP. To mimic this hyper phosphorylation we used CTD mutants with serines 2 or 5 substituted by glutamic acids and found that they not only display lower elongation rates but duplicate the effects of UV light on AS in the absence of irradiation. Consistently, substitution of the serines with alanines prevents the UV effect on splicing. These results represent the first in vivo proof of modulation of elongation in response to an environmental signal, affecting in turn the kinetic coupling between transcription and splicing. (authors)

Root Formation in Ethylene-Insensitive Plants1

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Clark, David G.; Gubrium, Erika K.; Barrett, James E.; Nell, Terril A.; Klee, Harry J.

1999-01-01

Experiments with ethylene-insensitive tomato (Lycopersicon esculentum) and petunia (Petunia × hybrida) plants were conducted to determine if normal or adventitious root formation is affected by ethylene insensitivity. Ethylene-insensitive Never ripe (NR) tomato plants produced more belowground root mass but fewer aboveground adventitious roots than wild-type Pearson plants. Applied auxin (indole-3-butyric acid) increased adventitious root formation on vegetative stem cuttings of wild-type plants but had little or no effect on rooting of NR plants. Reduced adventitious root formation was also observed in ethylene-insensitive transgenic petunia plants. Applied 1-aminocyclopropane-1-carboxylic acid increased adventitious root formation on vegetative stem cuttings from NR and wild-type plants, but NR cuttings produced fewer adventitious roots than wild-type cuttings. These data suggest that the promotive effect of auxin on adventitious rooting is influenced by ethylene responsiveness. Seedling root growth of tomato in response to mechanical impedance was also influenced by ethylene sensitivity. Ninety-six percent of wild-type seedlings germinated and grown on sand for 7 d grew normal roots into the medium, whereas 47% of NR seedlings displayed elongated taproots, shortened hypocotyls, and did not penetrate the medium. These data indicate that ethylene has a critical role in various responses of roots to environmental stimuli. PMID:10482660

An evaluation of inexpensive methods for root image acquisition when using rhizotrons.

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Mohamed, Awaz; Monnier, Yogan; Mao, Zhun; Lobet, Guillaume; Maeght, Jean-Luc; Ramel, Merlin; Stokes, Alexia

2017-01-01

Belowground processes play an essential role in ecosystem nutrient cycling and the global carbon budget cycle. Quantifying fine root growth is crucial to the understanding of ecosystem structure and function and in predicting how ecosystems respond to climate variability. A better understanding of root system growth is necessary, but choosing the best method of observation is complex, especially in the natural soil environment. Here, we compare five methods of root image acquisition using inexpensive technology that is currently available on the market: flatbed scanner, handheld scanner, manual tracing, a smartphone application scanner and a time-lapse camera. Using the five methods, root elongation rate (RER) was measured for three months, on roots of hybrid walnut ( Juglans nigra  ×  Juglans regia L.) in rhizotrons installed in agroforests. When all methods were compared together, there were no significant differences in relative cumulative root length. However, the time-lapse camera and the manual tracing method significantly overestimated the relative mean diameter of roots compared to the three scanning methods. The smartphone scanning application was found to perform best overall when considering image quality and ease of use in the field. The automatic time-lapse camera was useful for measuring RER over several months without any human intervention. Our results show that inexpensive scanning and automated methods provide correct measurements of root elongation and length (but not diameter when using the time-lapse camera). These methods are capable of detecting fine roots to a diameter of 0.1 mm and can therefore be selected by the user depending on the data required.

The density and length of root hairs are enhanced in response to cadmium and arsenic by modulating gene expressions involved in fate determination and morphogenesis of root hairs in Arabidopsis

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Ramin Bahmani

2016-11-01

Full Text Available Root hairs are tubular outgrowths that originate from epidermal cells. Exposure of Arabidopsis to cadmium (Cd and arsenic [arsenite, As(III] increases root hair density and length. To examine the underlying mechanism, we measured the expression of genes involved in fate determination and morphogenesis of root hairs. Cd and As(III downregulated TTG1 and GL2 (negative regulators of fate determination and upregulated GEM (positive regulator, suggesting that root hair fate determination is stimulated by Cd and As(III. Cd and As(III increased the transcript levels of genes involved in root hair initiation (RHD6 and AXR2 and root hair elongation (AUX1, AXR1, ETR1, and EIN2 except CTR1. DR5::GUS transgenic Arabidopsis showed a higher DR5 expression in the root tip, suggesting that Cd and As(III increased the auxin content in the root tip. Knockdown of TTG1 in Arabidopsis resulted in increased root hair density and decreased root hair length compared with the control (Col-0 on 1/2 MS media. This phenotype may be attributed to the downregulation of GL2 and CTR1 and upregulation of RHD6. By contrast, gem mutant plants displayed a decrease in root hair density and length with reduced expression of RHD6, AXR2, AUX1, AXR1, ETR1, CTR1, and EIN2. Taken together, our results indicate that fate determination, initiation, and elongation of root hairs are stimulated in response to Cd and As(III through the modulation of the expression of genes involved in these processes in Arabidopsis.

Apoplastic pH in corn root gravitropism: a laser scanning confocal microscopy measurement

International Nuclear Information System (INIS)

Taylor, D.P.; Slattery, J.; Leopold, A.C.

1996-01-01

The ability to measure the pH of the apoplast in situ is of special interest as a test of the cell wall acidification theory. Optical sectioning of living seedlings of corn roots using the laser scanning confocal microscope (LSCM) permits us to make pH measurements in living tissue. The pH of the apoplast of corn roots was measured by this method after infiltration with CI-NERF, a pH-sensitive dye, along with Texas Red Dextran 3000, a pH-insensitive dye, as an internal standard. In the elongation zone of corn roots, the mean apoplastic pH was 4.9. Upon gravitropic stimulation, the pH on the convex side of actively bending roots was 4.5. The lowering of the apoplastic pH by 0.4 units appears to be sufficient to account for the increased growth on that side. This technique provides site-specific evidence for the acid growth theory of cell elongation. The LSCM permits measurements of the pH of living tissues, and has a sensitivity of approximately 0.2 pH units. (author)

Exogenous nitrate induces root branching and inhibits primary root growth in Capsicum chinense Jacq.

Science.gov (United States)

Celis-Arámburo, Teresita de Jesús; Carrillo-Pech, Mildred; Castro-Concha, Lizbeth A; Miranda-Ham, María de Lourdes; Martínez-Estévez, Manuel; Echevarría-Machado, Ileana

2011-12-01

The effects of nitrate (NO₃⁻) on the root system are complex and depend on several factors, such as the concentration available to the plant, endogenous nitrogen status and the sensitivity of the species. Though these effects have been widely documented on Arabidopsis and cereals, no reports are available in the Capsicum genus. In this paper, we have determined the effect of an exogenous in vitro application of this nutrient on root growth in habanero pepper (Capsicum chinense Jacq.). Exposure to NO₃⁻ inhibited primary root growth in both, dose- and time-dependent manners. The highest inhibition was attained with 0.1 mM NO₃⁻ between the fourth and fifth days of treatment. Inhibition of primary root growth was observed by exposing the root to both homogeneous and heterogeneous conditions of the nutrient; in contrast, ammonium was not able to induce similar changes. NO₃⁻-induced inhibition of primary root growth was reversed by treating the roots with IAA or NPA, a polar auxin transport inhibitor. Heterogeneous NO₃⁻ application stimulated the formation and elongation of lateral roots in the segment where the nutrient was present, and this response was influenced by exogenous phytohormones. These results demonstrate that habanero pepper responds to NO₃⁻ in a similar fashion to other species with certain particular differences. Therefore, studies in this model could help to elucidate the mechanisms by which roots respond to NO₃⁻ in fluctuating soil environments. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Transcriptomics insights into the genetic regulation of root apical meristem exhaustion and determinate primary root growth in Pachycereus pringlei (Cactaceae).

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Rodriguez-Alonso, Gustavo; Matvienko, Marta; López-Valle, Mayra L; Lázaro-Mixteco, Pedro E; Napsucialy-Mendivil, Selene; Dubrovsky, Joseph G; Shishkova, Svetlana

2018-06-04

Many Cactaceae species exhibit determinate growth of the primary root as a consequence of root apical meristem (RAM) exhaustion. The genetic regulation of this growth pattern is unknown. Here, we de novo assembled and annotated the root apex transcriptome of the Pachycereus pringlei primary root at three developmental stages, with active or exhausted RAM. The assembled transcriptome is robust and comprehensive, and was used to infer a transcriptional regulatory network of the primary root apex. Putative orthologues of Arabidopsis regulators of RAM maintenance, as well as putative lineage-specific transcripts were identified. The transcriptome revealed putative orthologues of most proteins involved in housekeeping processes, hormone signalling, and metabolic pathways. Our results suggest that specific transcriptional programs operate in the root apex at specific developmental time points. Moreover, the transcriptional state of the P. pringlei root apex as the RAM becomes exhausted is comparable to the transcriptional state of cells from the meristematic, elongation, and differentiation zones of Arabidopsis roots along the root axis. We suggest that the transcriptional program underlying the drought stress response is induced during Cactaceae root development, and that lineage-specific transcripts could contribute to RAM exhaustion in Cactaceae.

Molecular mechanisms of root gravity sensing and signal transduction.

Science.gov (United States)

Strohm, Allison K; Baldwin, Katherine L; Masson, Patrick H

2012-01-01

Plants use gravity as a guide to direct their roots down into the soil to anchor themselves and to find resources needed for growth and development. In higher plants, the columella cells of the root tip form the primary site of gravity sensing, and in these cells the sedimentation of dense, starch-filled plastids (amyloplasts) triggers gravity signal transduction. This generates an auxin gradient across the root cap that is transmitted to the elongation zone where it promotes differential cell elongation, allowing the root to direct itself downward. It is still not well understood how amyloplast sedimentation leads to auxin redistribution. Models have been proposed to explain how mechanosensitive ion channels or ligand-receptor interactions could connect these events. Although their roles are still unclear, possible second messengers in this process include protons, Ca(2+), and inositol 1,4,5-triphosphate. Upon gravistimulation, the auxin efflux facilitators PIN3 and PIN7 relocalize to the lower side of the columella cells and mediate auxin redistribution. However, evidence for an auxin-independent secondary mechanism of gravity sensing and signal transduction suggests that this physiological process is quite complex. Furthermore, plants must integrate a variety of environmental cues, resulting in multifaceted relationships between gravitropism and other directional growth responses such as hydro-, photo-, and thigmotropism. Copyright © 2011 Wiley Periodicals, Inc.

Inhibition of phospholipase C disrupts cytoskeletal organization and gravitropic growth in Arabidopsis roots.

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Andreeva, Zornitza; Barton, Deborah; Armour, William J; Li, Min Y; Liao, Li-Fen; McKellar, Heather L; Pethybridge, Kylie A; Marc, Jan

2010-10-01

The phospholipase protein superfamily plays an important role in hormonal signalling and cellular responses to environmental stimuli. There is also growing evidence for interactions between phospholipases and the cytoskeleton. In this report we used a pharmacological approach to investigate whether inhibiting a member of the phospholipase superfamily, phospholipase C (PLC), affects microtubules and actin microfilaments as well as root growth and morphology of Arabidopsis thaliana seedlings. Inhibiting PLC activity using the aminosteroid U73122 significantly inhibited root elongation and disrupted root morphology in a concentration-dependent manner, with the response being saturated at 5 μM, whereas the inactive analogue U73343 was ineffective. The primary root appeared to lose growth directionality accompanied by root waving and formation of curls. Immunolabelling of roots exposed to increasingly higher U73122 concentrations revealed that the normal transverse arrays of cortical microtubules in the elongation zone became progressively more disorganized or depolymerized, with the disorganization appearing within 1 h of incubation. Likewise, actin microfilament arrays also were disrupted. Inhibiting PLC using an alternative inhibitor, neomycin, caused similar disruptions to both cytoskeletal organization and root morphology. In seedlings gravistimulated by rotating the culture plates by 90°, both U73122 and neomycin disrupted the normal gravitropic growth of roots and etiolated hypocotyls. The effects of PLC inhibitors are therefore consistent with the notion that, as with phospholipases A and D, PLC likewise interacts with the cytoskeleton, alters growth morphology, and is involved in gravitropism.

Polyamines and meristematic activity in Zea mays roots

International Nuclear Information System (INIS)

Schwartz, M.; Arzee, T.; Cohen, Y.; Altman, A.

1989-01-01

Polyamine content and biosynthesis were determined in conjunction with meristematic activity and growth of Zea mays roots. Three types of developmental events were investigated: growth of intact primary roots, formation of lateral root primordia following main root decapitation, and activity of the quiescent center following root cap excision. A low ratio of putrescine/spermidine cotents was found to be salient feature of regions with high meristematic activity, in all 3 experimental systems. Arginine decarboxylase (ADC) and ornithine decarboxylase (ODC) activities increased concomitantly with lateral root primordia development and activation of the quiescent center. An increase in the incorporation of arginine and ornithine into spermidine was found in meristematic zones. L-canavanine inhibited primary root elongation and formation of lateral primordia as well as ADC and ODC activity. Similar inhibitory effects were found with MGBG and CHA, both inhibitors of polyamine biosynthesis. A parallel study of ODC localization and DNA synthesis (using α- 14 C-DFMO and 3 H-thymidine microautoradiography, respectively) revealed than root zones with high meristematic activity are characterized by high ODC activity

Root canal irrigants

OpenAIRE

Kandaswamy, Deivanayagam; Venkateshbabu, Nagendrababu

2010-01-01

Successful root canal therapy relies on the combination of proper instrumentation, irrigation, and obturation of the root canal. Of these three essential steps of root canal therapy, irrigation of the root canal is the most important determinant in the healing of the periapical tissues. The primary endodontic treatment goal must thus be to optimize root canal disinfection and to prevent reinfection. In this review of the literature, various irrigants and the interactions between irrigants are...

Sites and regulation of auxin biosynthesis in Arabidopsis roots.

Science.gov (United States)

Ljung, Karin; Hull, Anna K; Celenza, John; Yamada, Masashi; Estelle, Mark; Normanly, Jennifer; Sandberg, Göran

2005-04-01

Auxin has been shown to be important for many aspects of root development, including initiation and emergence of lateral roots, patterning of the root apical meristem, gravitropism, and root elongation. Auxin biosynthesis occurs in both aerial portions of the plant and in roots; thus, the auxin required for root development could come from either source, or both. To monitor putative internal sites of auxin synthesis in the root, a method for measuring indole-3-acetic acid (IAA) biosynthesis with tissue resolution was developed. We monitored IAA synthesis in 0.5- to 2-mm sections of Arabidopsis thaliana roots and were able to identify an important auxin source in the meristematic region of the primary root tip as well as in the tips of emerged lateral roots. Lower but significant synthesis capacity was observed in tissues upward from the tip, showing that the root contains multiple auxin sources. Root-localized IAA synthesis was diminished in a cyp79B2 cyp79B3 double knockout, suggesting an important role for Trp-dependent IAA synthesis pathways in the root. We present a model for how the primary root is supplied with auxin during early seedling development.

Synthesis of Elongated Microcapsules

Science.gov (United States)

Li, Wenyan; Buhrow, Jerry; Calle, Luz M.

2011-01-01

One of the factors that influence the effectiveness of self-healing in functional materials is the amount of liquid healing agents that can be delivered to the damaged area. The use of hollow tubes or fibers and the more sophisticated micro-vascular networks has been proposed as a way to increase the amount of healing agents that can be released when damage is inflicted. Although these systems might be effective in some specific applications, they are not practical for coatings applications. One possible practical way to increase the healing efficiency is to use microcapsules with high-aspect-ratios, or elongated microcapsules. It is understood that elongated microcapsules will be more efficient because they can release more healing agent than a spherical microcapsule when a crack is initiated in the coating. Although the potential advantage of using elongated microcapsules for self healing applications is clear, it is very difficult to make elongated microcapsules from an emulsion system because spherical microcapsules are normally formed due to the interfacial tension between the dispersed phase and the continuous phase. This paper describes the two methods that have been developed by the authors to synthesize elongated microcapsules. The first method involves the use of an emulsion with intermediate stability and the second involves the application of mechanical shear conditions to the emulsion.

The Response of Duckweed (Lemna minor L. Roots to Cd and Its Chemical Forms

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Yan Xue

2018-01-01

Full Text Available The response of duckweed (Lemna minor L. roots to Cd and its chemical forms was investigated. The relative root growth rate and concentrations of Cd and its different chemical forms in the root, that is, ethanol-extractable (FE-Cd, HCl-extractable (FHCl-Cd, and residual fractions (Fr-Cd, were quantified. Weibull model was used to unravel the regression between the relative root elongation (RRL with chemical forms of Cd. Parameters assessed catalase (CAT, peroxidases (POD, and superoxide dismutase (SOD, as well as malondialdehyde (MDA and total antioxidant capacity (A-TOC. Our results show that both the relative root growth rate and relative frond number were affected by Cd concentrations. The chemical forms of Cd were influenced by Cd content in the medium. Relative root elongation (RRL showed a significant correlation with chemical forms of Cd. Additionally, POD and SOD increased at lower Cd concentrations followed by a decrease at higher Cd concentrations (at more than 5 μM Cd. Moreover, MDA and A-TOC increased and CAT decreased with increasing Cd exposure. Furthermore, CAT showed a significant correlation with FHCl-Cd. Taken together, it can be concluded that the chemical forms of Cd are statistically significant predictors of Cd toxicity to duckweed and to the other similar aquatic plants.

Linking hydrogen-mediated boron toxicity tolerance with improvement of root elongation, water status and reactive oxygen species balance: a case study for rice.

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Wang, Yu; Duan, Xingliang; Xu, Sheng; Wang, Ren; Ouyang, Zhaozeng; Shen, Wenbiao

2016-12-01

Boron is essential for plant growth but hazardous when present in excess. As the antioxidant properties of hydrogen gas (H 2 ) were recently described in plants, oxidative stress induced by excess boron was investigated along with other biological responses during rice (Oryza sativa) seed germination to study the beneficial role of H 2 METHODS: Rice seeds were pretreated with exogenous H 2 Using physiological, pharmacological and molecular approaches, the production of endogenous H 2 , growth status, reactive oxygen species (ROS) balance and relative gene expression in rice were measured under boron stress to investigate mechanisms of H 2 -mediated boron toxicity tolerance. In our test, boron-inhibited seed germination and seedling growth, and endogenous H 2 production, were obviously blocked by exogenously applying H 2 The re-establishment of ROS balance was confirmed by reduced lipid peroxidation and ROS accumulation. Meanwhile, activities of catalase (CAT) and peroxidase (POX) were increased. Suppression of pectin methylesterase (PME) activity and downregulation of PME transcripts by H 2 were consistent with the alleviation of root growth inhibition caused by boron. Water status was improved as well. This result was confirmed by the upregulation of genes encoding specific aquaporins (AQPs), the maintenance of low osmotic potential and high content of soluble sugar. Increased transcription of representative AQP genes (PIP2;7 in particular) and BOR2 along with decreased BOR1 mRNA may contribute to lowering boron accumulation. Hydrogen provides boron toxicity tolerance mainly by improving root elongation, water status and ROS balance. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Effects of different tillage and transplanting methods on rice rooting ability

International Nuclear Information System (INIS)

Ren Wanjun; Yang Wenyu; Fan Gaoqiong; Wu Jinxiu; Wang Lihong

2007-01-01

Effects of different tillage and transplanting methods on rice rooting ability were studied with the methods of water culture and 3 H labeling. The results showed that the dynamic curve of rooting ability had single peak during growth period, and the peak of root length per plant, root number and root dry weight appeared at booting. With conventional tillage and transplanting method, the rice plant had the strongest rooting ability, under non-tillage treatment (BCSNT), the rooting ability was the lowest during elongating to heading. After 10d of heading, the dry weight and 3 H specific activity of BCSNT was higher than other treatments, at the same time, the percentage of 3 H assimilate at new root was the highest. Dry weight was positively correlated with percentage of 3 H assimilate of new root, while negatively with percentage of 3 H assimilate of panicle. (authors)

Gravity sensing and signal transduction in vascular plant primary roots.

Science.gov (United States)

Baldwin, Katherine L; Strohm, Allison K; Masson, Patrick H

2013-01-01

During gravitropism, the potential energy of gravity is converted into a biochemical signal. How this transfer occurs remains one of the most exciting mysteries in plant cell biology. New experiments are filling in pieces of the puzzle. In this review, we introduce gravitropism and give an overview of what we know about gravity sensing in roots of vascular plants, with special highlight on recent papers. When plant roots are reoriented sideways, amyloplast resedimentation in the columella cells is a key initial step in gravity sensing. This process somehow leads to cytoplasmic alkalinization of these cells followed by relocalization of auxin efflux carriers (PINs). This changes auxin flow throughout the root, generating a lateral gradient of auxin across the cap that upon transmission to the elongation zone leads to differential cell elongation and gravibending. We will present the evidence for and against the following players having a role in transferring the signal from the amyloplast sedimentation into the auxin signaling cascade: mechanosensitive ion channels, actin, calcium ions, inositol trisphosphate, receptors/ligands, ARG1/ARL2, spermine, and the TOC complex. We also outline auxin transport and signaling during gravitropism.

Composite Cucurbita pepo plants with transgenic roots as a tool to study root development.

Science.gov (United States)

Ilina, Elena L; Logachov, Anton A; Laplaze, Laurent; Demchenko, Nikolay P; Pawlowski, Katharina; Demchenko, Kirill N

2012-07-01

In most plant species, initiation of lateral root primordia occurs above the elongation zone. However, in cucurbits and some other species, lateral root primordia initiation and development takes place in the apical meristem of the parental root. Composite transgenic plants obtained by Agrobacterium rhizogenes-mediated transformation are known as a suitable model to study root development. The aim of the present study was to establish this transformation technique for squash. The auxin-responsive promoter DR5 was cloned into the binary vectors pKGW-RR-MGW and pMDC162-GFP. Incorporation of 5-ethynyl-2'-deoxyuridine (EdU) was used to evaluate the presence of DNA-synthesizing cells in the hypocotyl of squash seedlings to find out whether they were suitable for infection. Two A. rhizogenes strains, R1000 and MSU440, were used. Roots containing the respective constructs were selected based on DsRED1 or green fluorescent protein (GFP) fluorescence, and DR5::Egfp-gusA or DR5::gusA insertion, respectively, was verified by PCR. Distribution of the response to auxin was visualized by GFP fluorescence or β-glucuronidase (GUS) activity staining and confirmed by immunolocalization of GFP and GUS proteins, respectively. Based on the distribution of EdU-labelled cells, it was determined that 6-day-old squash seedlings were suited for inoculation by A. rhizogenes since their root pericycle and the adjacent layers contain enough proliferating cells. Agrobacterium rhizogenes R1000 proved to be the most virulent strain on squash seedlings. Squash roots containing the respective constructs did not exhibit the hairy root phenotype and were morphologically and structurally similar to wild-type roots. The auxin response pattern in the root apex of squash resembled that in arabidopsis roots. Composite squash plants obtained by A. rhizogenes-mediated transformation are a good tool for the investigation of root apical meristem development and root branching.

Brassinolide Increases Potato Root Growth In Vitro in a Dose-Dependent Way and Alleviates Salinity Stress

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Yueqing Hu

2016-01-01

Full Text Available Brassinosteroids (BRs are steroidal phytohormones that regulate various physiological processes, such as root development and stress tolerance. In the present study, we showed that brassinolide (BL affects potato root in vitro growth in a dose-dependent manner. Low BL concentrations (0.1 and 0.01 μg/L promoted root elongation and lateral root development, whereas high BL concentrations (1–100 μg/L inhibited root elongation. There was a significant (P<0.05 positive correlation between root activity and BL concentrations within a range from 0.01 to 100 μg/L, with the peak activity of 8.238 mg TTC·g−1 FW·h−1 at a BL concentration of 100 μg/L. Furthermore, plants treated with 50 μg/L BL showed enhanced salt stress tolerance through in vitro growth. Under this scenario, BL treatment enhanced the proline content and antioxidant enzymes’ (superoxide dismutase, peroxidase, and catalase activity and reduced malondialdehyde content in potato shoots. Application of BL maintain K+ and Na+ homeostasis by improving tissue K+/Na+ ratio. Therefore, we suggested that the effects of BL on root development from stem fragments explants as well as on primary root development are dose-dependent and that BL application alleviates salt stress on potato by improving root activity, root/shoot ratio, and antioxidative capacity in shoots and maintaining K+/Na+ homeostasis in potato shoots and roots.

Testing the toxicity of metals, phenol, effluents, and receiving waters by root elongation in Lactuca sativa L.

Science.gov (United States)

Lyu, Jie; Park, Jihae; Kumar Pandey, Lalit; Choi, Soyeon; Lee, Hojun; De Saeger, Jonas; Depuydt, Stephen; Han, Taejun

2018-03-01

Phytotoxicity tests using higher plants are among the most simple, sensitive, and cost-effective of the methods available for ecotoxicity testing. In the present study, a hydroponic-based phytotoxicity test using seeds of Lactuca sativa was used to evaluate the water quality of receiving waters and effluents near two industrial sites (Soyo and Daejon) in Korea with respect to the toxicity of 10 metals (As, Cd, Cr, Cu, Fe, Pb, Mn, Hg, Ni, Zn) and phenol, and of the receiving waters and effluents themselves. First, the L. sativa hydroponic bioassay was used to determine whether the receiving water or effluents were toxic; then, the responsible toxicant was identified. The results obtained with the L. sativa bioassay ranked the EC 50 toxicities of the investigated metal ions and phenol as: Cd > Ni > Cu > Zn > Hg > phenol > As > Mn > Cr > Pb > Fe. We found that Zn was the toxicant principally responsible for toxicity in Daejeon effluents. The Daejeon field effluent had a higher Zn concentration than permitted by the effluent discharge criteria of the Ministry of Environment of Korea. Our conclusion on the importance of Zn toxicity was supported by the results of the L. sativa hydroponic assay, which showed that the concentration of Zn required to inhibit root elongation in L. sativa by 50% (EC 50 ) was higher in the Daejeon field effluent than that of pure Zn. More importantly, we proved that the L. sativa hydroponic test method can be applied not only as an alternative tool for determining whether a given waste is acceptable for discharge into public water bodies, but also as an alternative method for measuring the safety of aquatic environments using EC 20 values, with respect to the water pollutants investigated (i.e., Cd, Cr, Cu, Pb, Mn, Hg, Ni, Zn, and phenol). Copyright © 2017. Published by Elsevier Inc.

Measuring and Modeling Root Distribution and Root Reinforcement in Forested Slopes for Slope Stability Calculations

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Cohen, D.; Giadrossich, F.; Schwarz, M.; Vergani, C.

2016-12-01

Roots provide mechanical anchorage and reinforcement of soils on slopes. Roots also modify soil hydrological properties (soil moisture content, pore-water pressure, preferential flow paths) via subsurface flow path associated with root architecture, root density, and root-size distribution. Interactions of root-soil mechanical and hydrological processes are an important control of shallow landslide initiation during rainfall events and slope stability. Knowledge of root-distribution and root strength are key components to estimate slope stability in vegetated slopes and for the management of protection forest in steep mountainous area. We present data that show the importance of measuring root strength directly in the field and present methods for these measurements. These data indicate that the tensile force mobilized in roots depends on root elongation (a function of soil displacement), root size, and on whether roots break in tension of slip out of the soil. Measurements indicate that large lateral roots that cross tension cracks at the scarp are important for slope stability calculations owing to their large tensional resistance. These roots are often overlooked and when included, their strength is overestimated because extrapolated from measurements on small roots. We present planned field experiments that will measure directly the force held by roots of different sizes during the triggering of a shallow landslide by rainfall. These field data are then used in a model of root reinforcement based on fiber-bundle concepts that span different spacial scales, from a single root to the stand scale, and different time scales, from timber harvest to root decay. This model computes the strength of root bundles in tension and in compression and their effect on soil strength. Up-scaled to the stand the model yields the distribution of root reinforcement as a function of tree density, distance from tree, tree species and age with the objective of providing quantitative

Effects of N fertilizer on root growth in Zea mays L. seedlings

Energy Technology Data Exchange (ETDEWEB)

Wang, Z. R.; Rui, Y. R.; Shen, J. B.; Zhang, F. S.

2008-07-01

This paper reports the effects of different nitrogen (N) fertilizer levels on the growth of maize (Zea mays L.) under field conditions. The N supply was found to influence the growth of the plants, especially the roots. A high N supply significantly inhibited root elongation, and was associated with reduced root dry weight compared to controls and to plants grown with smaller supplies of N. However, no differences were seen in lateral primary root density under the different N supply conditions, nor did plant N concentration increase with high N supply. In conclusion, a high N supply not only wastes resources and pollutes the environment, it may also inhibit root growth. (Author)

Elongational viscosity of narrow molar mass distribution polystyrene

DEFF Research Database (Denmark)

Bach, Anders; Almdal, Kristoffer; Rasmussen, Henrik Koblitz

2003-01-01

Transient and steady elongational viscosity has been measured for two narrow molar mass distribution polystyrene melts of molar masses 200 000 and 390 000 by means of a filament stretching rheometer. Total Hencky strains of about five have been obtained. The transient elongational viscosity rises...... above the linear viscoelastic prediction at intermediate strains, indicating strain hardening. The steady elongational viscosities are monotone decreasing functions of elongation rate. At elongation rates larger than the inverse reptation time, the steady elongational viscosity scales linearly...

Submergence of Roots for Alveolar Bone Preservation. I. Endodontically Treated Roots.

Science.gov (United States)

1977-05-10

With Endodontic Submerged Roots Scale 0 1 2 3 Periapical 15 0 1 0 Pericoronal 7 3 3 3 (3 cysts ) = 1 _ _ _ _ _ _ _ _ _ = REFERENCES 1. Lam, R.: Contour...with coronal portions of the roots. These epithe lial-lined cysts prevented the formation of osteo- cementum over the coronal surface . In this study...the endodontically treated roots appeared to be primarily a response to the excess root cana l sealer that was expressed coronally and periapically

Elongational viscosity of multiarm (Pom-Pom) polystyrene

DEFF Research Database (Denmark)

Nielsen, Jens Kromann; Rasmussen, Henrik K.; Almdal, Kristoffer

2006-01-01

-Pom was estimated to have 2.5 arms on average, while the estimate is 3.3 for the asymmetric star. The molar mass of each arm is about 27 kg/mol. The melts were characterized in the linear viscoelastic regime and in non-linear elongational rheometry. The transient elongational viscosity for the Pom-Pom molecule...... it corresponds well with an estimate of the maximum stretchability of the backbone. Time-strain separability was not observed for the 'Asymmetric star' molecule at the elongation rates investigated. The transient elongational viscosity for the 'Pom-Pom' molecule went through a reproducible maximum...... in the viscosity at the highest elongational rate....

Complete disintegration of the microtubular cytoskeleton precedes its auxin-mediated reconstruction in postmitotic maize root cells

Science.gov (United States)

Baluska, F.; Barlow, P. W.; Volkmann, D.

1996-01-01

The inhibitory action of 0.1 microM auxin (IAA) on maize root growth was closely associated with a rapid and complete disintegration of the microtubular (MT) cytoskeleton, as visualized by indirect immunofluorescence of tubulin, throughout the growth region. After 30 min of this treatment, only fluorescent spots were present in root cells, accumulating either around nuclei or along cell walls. Six h later, in addition to some background fluorescence, dense but partially oriented oblique or longitudinal arrays of cortical MTs (CMTs) were found in most growing cells of the root apex. After 24 h of treatment, maize roots had adapted to the auxin, as inferred from the slowly recovering elongation rate and from the reassembly of a dense and well-ordered MT cytoskeleton which showed only slight deviations from that of the control root cells. Taxol pretreatment (100 microM, 24 h) prevented not only the rapid auxin-mediated disintegration of the MT cytoskeleton but also a reorientation of the CMT arrays, from transversal to longitudinal. The only tissue to show MTs in their cells throughout the auxin treatment was the epidermis. Significant resistance of transverse CMT arrays in these cells towards auxin was confirmed using a higher auxin concentration (100 microM, 24 h). The latter auxin dose also revealed inter-tissue-specific responses to auxin: outer cortical cell files reoriented their CMTs from the transversal to longitudinal orientation, whereas inner cortical cell files lost their MTs. This high auxin-mediated response, associated with the swelling of root apices, was abolished with the pretreatment of maize root with taxol.

Water Deficit and Abscisic Acid Cause Differential Inhibition of Shoot versus Root Growth in Soybean Seedlings 1

Science.gov (United States)

Creelman, Robert A.; Mason, Hugh S.; Bensen, Robert J.; Boyer, John S.; Mullet, John E.

1990-01-01

Roots often continue to elongate while shoot growth is inhibited in plants subjected to low-water potentials. The cause of this differential response to water deficit was investigated. We examined hypocotyl and root growth, polysome status and mRNA populations, and abscisic acid (ABA) content in etiolated soybean (Glycine max [L.] Merr. cv Williams) seedlings whose growth was inhibited by transfer to low-water potential vermiculite or exogenous ABA. Both treatments affected growth and dry weight in a similar fashion. Maximum inhibition of hypocotyl growth occurred when internal ABA levels (modulated by ABA application) reached the endogenous level found in the elongating zone of seedlings grown in water-deficient vermiculite. Conversely, root growth was affected to only a slight extent in low-water potential seedlings and by most ABA treatments (in some, growth was promoted). In every seedling section examined, transfer of seedlings into low-water potential vermiculite caused ABA levels to increase approximately 5- to 10-fold over that found in well-watered seedlings. Changes in soluble sugar content, polysome status, and polysome mRNA translation products seen in low-water potential seedlings did not occur with ABA treatments sufficient to cause significant inhibition of hypocotyl elongation. These data suggest that both variation in endogenous ABA levels, and differing sensitivity to ABA in hypocotyls and roots can modulate root/shoot growth ratios. However, exogenous ABA did not induce changes in sugar accumulation, polysome status, and mRNA populations seen after transfer into low-water potential vermiculite. Images Figure 6 Figure 7 PMID:16667248

Studying preventive effects of Berberisintegerrimaon root on carbon tetrachloride induced hepatotoxicity in broilers

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mohammadreza mohammadimalayeri

2013-11-01

Full Text Available Liver diseases and their economic losses have gained more importancealongside the development of integrated poultry industry. Studies have proved hepatotoxicity induced by carbon tetrachloride as one of the best experimental models of hepatotocicity. Barberries have been used widely in traditional medicine.The purpose of the present study was to evaluaterthe preventive effects of Berberisintegerrima root on carbon tetrachloride induced liver lesions in broilers.For this purpose, 80 day old Ross strain broilers were divided randomly to 8 study groupsconsisting of negative control, positive control which received IP 4ml/kg b.w. carbon tetrachloride twice in 25th and 28thdays , treatment controls consisting of 10,20 and 30 grams of  Berberisintegerrima root per kilogram of diet and treatment groups consisting of 10,20 and 30 gr. Of Berberis root / Kg diet + IPcarbontetrachloride 4ml/Kg b.w. twice in 25th and 28th days.At 29th day, blood samples were collected from animals, then they were sacrificed and their liver samples were fixed in 10% formalin solution. The blood samples were sent to laboratory to measure ALT,AST and ALP activities.Biochemical results didn't show any significant changes of ALT,AST and ALP activities between all study groups (P>0.05. Microscopic results showed significant decrease in pathologic lesions of 20 gr Berberis root /Kg diet treatment group in comparison with the positive control group(P

The contribution of cell wall composition in the expansion of Camellia sinensis seedlings roots in response to aluminum.

Science.gov (United States)

Safari, Masoumeh; Ghanati, Faezeh; Safarnejad, Mohammad Reza; Chashmi, Najmeh Ahmadian

2018-02-01

Treatment with aluminum triggers a unique response in tea seedlings resulting in biochemical modification of the cell wall, regulation of the activity of the loosening agents, and elongation of root. Unlike most terrestrial plants, tea (Camellia sinensis L.) responds to aluminum (Al) through the promotion of its root elongation; but the real mechanism(s) behind this phenomenon is not well understood. A plausible relationship between the modifications of the cell wall and the promotion of root elongation was examined in tea seedlings treated for 8 days with 400 µM Al. The mechanical properties of the cell wall, the composition of its polysaccharides and their capacity to absorb Al, the expression of genes, and the activities of the wall-modifying proteins were studied. With 6 h of the treatment, about 40% of the absorbed Al was bound to the cell wall; however, the amount did not increase thereafter. Meanwhile, the activity of pectin methylesterase, the level of pectin demethylation, the amounts and the average molecular mass of xyloglucan in the root apices significantly decreased upon exposure to Al, resulting in the reduction of Al binding sites. On the other hand, the activity and the gene expression of peroxidase decreased, whereas the activity and gene expression of xyloglucan-degrading enzymes, the expression of expansin A and the H + -ATPase4 genes increased in the Al-treated plants. Interestingly, it was accompanied by the increase of elastic and viscous extensibility of the root apices. From the results, it can be suggested that the biochemical modification of the cell walls reduces sites of Al binding to roots and triggers the activity of the loosening agents, thereby increasing the length of tea roots.

An auxin transport independent pathway is involved in phosphate stress-induced root architectural alterations in Arabidopsis. Identification of BIG as a mediator of auxin in pericycle cell activation.

Science.gov (United States)

López-Bucio, José; Hernández-Abreu, Esmeralda; Sánchez-Calderón, Lenin; Pérez-Torres, Anahí; Rampey, Rebekah A; Bartel, Bonnie; Herrera-Estrella, Luis

2005-02-01

Arabidopsis (Arabidopsis thaliana) plants display a number of root developmental responses to low phosphate availability, including primary root growth inhibition, greater formation of lateral roots, and increased root hair elongation. To gain insight into the regulatory mechanisms by which phosphorus (P) availability alters postembryonic root development, we performed a mutant screen to identify genetic determinants involved in the response to P deprivation. Three low phosphate-resistant root lines (lpr1-1 to lpr1-3) were isolated because of their reduced lateral root formation in low P conditions. Genetic and molecular analyses revealed that all lpr1 mutants were allelic to BIG, which is required for normal auxin transport in Arabidopsis. Detailed characterization of lateral root primordia (LRP) development in wild-type and lpr1 mutants revealed that BIG is required for pericycle cell activation to form LRP in both high (1 mm) and low (1 microm) P conditions, but not for the low P-induced alterations in primary root growth, lateral root emergence, and root hair elongation. Exogenously supplied auxin restored normal lateral root formation in lpr1 mutants in the two P treatments. Treatment of wild-type Arabidopsis seedlings with brefeldin A, a fungal metabolite that blocks auxin transport, phenocopies the root developmental alterations observed in lpr1 mutants in both high and low P conditions, suggesting that BIG participates in vesicular targeting of auxin transporters. Taken together, our results show that auxin transport and BIG function have fundamental roles in pericycle cell activation to form LRP and promote root hair elongation. The mechanism that activates root system architectural alterations in response to P deprivation, however, seems to be independent of auxin transport and BIG.

Aphidicolin-induced nuclear elongation in tobacco BY-2 cells.

Science.gov (United States)

Yasuhara, Hiroki; Kitamoto, Kazuki

2014-05-01

Plant nuclei are known to differentiate into various shapes within a single plant. However, little is known about the mechanisms of nuclear morphogenesis. We found that nuclei of tobacco BY-2 cells were highly elongated on long-term treatment with 5 mg l⁻¹ aphidicolin, an inhibitor of DNA polymerase α. In aphidicolin-treated cells, the nuclear length was correlated with the cell length. During culture in the presence of aphidicolin, the nuclei were elongated in parallel with cell elongation. Nuclear elongation was inhibited by the inhibition of cell elongation with 2,6-dichlorobenzonitrile, a cellulose synthesis inhibitor. However, cell elongation induced in the auxin-depleted medium in the absence of aphidicolin did not cause nuclear elongation, indicating that cell elongation alone is not sufficient for nuclear elongation. Treatment with either latrunculin B or propyzamide inhibited the aphidicolin-induced nuclear elongation, indicating that both actin filaments and microtubules (MTs) are required for nuclear elongation. Observations using BY-YTHCLR2 cells, in which actin filaments, MTs and nuclei were simultaneously visualized, revealed that the longitudinally arranged MT bundles associated with the nucleus play an important role in nuclear elongation, and that actin filaments affect the formation of these MT bundles. In aphidicolin-treated cells, the nuclear DNA contents of the elongated nuclei exceeded 4C, and the nuclear length was highly correlated with the nuclear DNA content. In cells treated with 50 mg l⁻¹ aphidicolin, cells were elongated and nucleus-associated longitudinal MT bundles were formed, but the nuclear DNA contents did not exceed 4C and the nuclei did not elongate. These results indicate that an increase in the nuclear DNA content above 4C is also required for nuclear elongation.

Influence of indole-butyric acid and electro-pulse on in vitro rooting and development of olive (Olea europea L.) microshoots.

Science.gov (United States)

Padilla, Isabel Maria Gonzalez; Vidoy, I; Encina, C L

2009-09-01

The effects of indole-butyric acid (IBA) and electro-pulses on rooting and shoot growth were studied in vitro, using olive shoot cultures. Tested shoots were obtained from seedlings belonging to three Spanish cultivars, 'Arbequina', 'Manzanilla de Sevilla' and 'Gordal Sevillana', which have easy-, medium- and difficult-to-root rooting abilities, respectively. The standard two-step rooting method (SRM), consisting of root induction in olive rooting medium supplemented with 0, 0.1 or 1 mg/l IBA followed by root elongation in the same rooting medium without IBA, was compared with a novel one-step method consisting of shoot electro-pulses of 250, 1,250 or 2,500 V in a solution of IBA (0, 0.1 or 1 mg/l) and direct transferral to root elongation medium. The rooting percentage of the seedling-derived shoots obtained with the SRM was 76% for 'Arbequina' and 'Gordal Sevillana' cultivars and 100% for 'Manzanilla de Sevilla' cultivar, whereas with the electro-pulse method, the rooting percentages were 68, 64 and 88%, respectively. IBA dipping without pulse produced 0% rooting in 'Arbequina' seedling-derived shoots. The electroporation in IBA not only had an effect on shoot rooting but also on shoot growth and development, with longer shoots and higher axillary shoot sprouting and growth after some of the treatments. These effects were cultivar-dependent. The electro-pulse per se could explain some of these effects on shoot development.

Genetic interaction of two abscisic acid signaling regulators, HY5 and FIERY1, in mediating lateral root formation

KAUST Repository

Chen, Hao

2011-01-01

Root architecture is continuously shaped in a manner that helps plants to better adapt to the environment. Gene regulation at the transcriptional or post-transcriptional levels largely controls this environmental response. Recently, RNA silencing has emerged as an important player in gene regulation and is involved in many aspects of plant development, including lateral root formation. In a recent study, we found that FIERY1, a bifunctional abiotic stress and abscisic acid (ABA) signaling regulator and an endogenous RNA silencing suppressor, mediates auxin response during lateral root formation in Arabidopsis. We proposed that FRY1 regulates lateral root development through its activity on adenosine 3,5-bisphosphate (PAP), a strong inhibitor of exoribonucleases (XRNs). Interestingly, some of the phenotypes of fry1, such as enhanced response to light in repressing hypocotyl elongation and hypersensitivity to ABA in lateral root growth, are opposite to those of another light- and ABA-signaling mutant, hy5. Here we analyzed the hy5 fry1 double mutant for root and hypocotyl growth. We found that the hy5 mutation can suppress the enhanced light sensitivity in fry1 hypocotyl elongation and restore the lateral root formation. The genetic interaction between HY5 and FRY1 indicates that HY5 and FRY1 may act in overlapping pathways that mediate light signaling and lateral root development. © 2011 Landes Bioscience.

The interaction between glucose and cytokinin signaling in controlling Arabidopsis thaliana seedling root growth and development.

Science.gov (United States)

Kushwah, Sunita; Laxmi, Ashverya

2017-05-04

Cytokinin (CK) and glucose (GLC) control several common responses in plants. There is an extensive overlap between CK and GLC signal transduction pathways in Arabidopsis. Physiologically, both GLC and CK could regulate root length in light. CK interacts with GLC via HXK1 dependent pathway for root length control. Wild-type (WT) roots cannot elongate in the GLC free medium while CK-receptor mutant ARABIDOPSIS HISTIDINE KINASE4 (ahk4) and type B ARR triple mutant ARABIDOPSIS RESPONSE REGULATOR1, 10,11 (arr1, 10,11) roots could elongate even in the absence of GLC as compared with the WT. The root hair initiation was also found defective in CK signaling mutants ahk4, arr1,10,11 and arr3,4,5,6,8,9 on increasing GLC concentration (up to 3%); and lesser number of root hairs were visible even at 5% GLC as compared with the WT. Out of 941 BAP regulated genes, 103 (11%) genes were involved in root growth and development. Out of these 103 genes, 60 (58%) genes were also regulated by GLC. GLC could regulate 5736 genes, which include 327 (6%) genes involved in root growth and development. Out of these 327 genes, 60 (18%) genes were also regulated by BAP. Both GLC and CK signaling cannot alter root length in light in auxin signaling mutant AUXIN RESPONSE3/INDOLE-3-ACETIC ACID17 (axr3/iaa17) suggesting that they may involve auxin signaling component as a nodal point. Therefore CK- and GLC- signaling are involved in controlling different aspects of root growth and development such as root length, with auxin signaling components working as downstream target.

Plant cell wall polysaccharide analysis during cell elongation

DEFF Research Database (Denmark)

Guo, Xiaoyuan

Plant cell walls are complex structures whose composition and architecture are important to various cellular activities. Plant cell elongation requires a high level of rearrangement of the cell wall polymers to enable cell expansion. However, the cell wall polysaccharides dynamics during plant cell...... elongation is poorly understood. This PhD project aims to elucidate the cell wall compositional and structural change during cell elongation by using Comprehensive Microarray Polymer Profiling (CoMPP), microscopic techniques and molecular modifications of cell wall polysaccharide. Developing cotton fibre......, pea and Arabidopsis thaliana were selected as research models to investigate different types of cell elongation, developmental elongation and tropism elongation. A set of comprehensive analysis covering 4 cotton species and 11 time points suggests that non-cellulosic polysaccharides contribute...

Systemic control of cell division and endoreduplication by NAA and BAP by modulating CDKs in root tip cells of Allium cepa.

Science.gov (United States)

Tank, Jigna G; Thaker, Vrinda S

2014-01-01

Molecular mechanism regulated by auxin and cytokinin during endoreduplication, cell division, and elongation process is studied by using Allium cepa roots as a model system. The activity of CDK genes modulated by auxin and cytokinin during cell division, elongation, and endoreduplication process is explained in this research work. To study the significance of auxin and cytokinin in the management of cell division and endoreduplication process in plant meristematic cells at molecular level endoreduplication was developed in root tips of Allium cepa by giving colchicine treatment. There were inhibition of vegetative growth, formation of c-tumor at root tip, and development of endoreduplicated cells after colchicine treatment. This c-tumor was further treated with NAA and BAP to reinitiate vegetative growth in roots. BAP gave positive response in reinitiation of vegetative growth of roots from center of c-tumor. However, NAA gave negative response in reinitiation of vegetative growth of roots from c-tumor. Further, CDKs gene expression analysis from normal, endoreduplicated, and phytohormone (NAA or BAP) treated root tip was done and remarkable changes in transcription level of CDK genes in normal, endoreduplicated, and phytohormones treated cells were observed.

Taurodontism: A case report of successful treatment of root and crown

Directory of Open Access Journals (Sweden)

Abdolsamadi HR.

2006-08-01

Full Text Available Taurodontism is a rare dental anomaly in which the involved tooth has enlarged and elongated body and pulp chamber with apical displacement of the pulpal floor. Endodontic treatment of these teeth is challenging because it requires identifying the number of root canals. A case of bilateral involvement of maxillary first molar teeth is presented. Endodontic treatment of the right maxillary first molar with taurodontism was indicated due to irreversible pulpitis. In this article, we described the procedure of root canal therapy for this case.

Translational Control of Cell Division by Elongator

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Fanelie Bauer

2012-05-01

Full Text Available Elongator is required for the synthesis of the mcm5s2 modification found on tRNAs recognizing AA-ending codons. In order to obtain a global picture of the role of Elongator in translation, we used reverse protein arrays to screen the fission yeast proteome for translation defects. Unexpectedly, this revealed that Elongator inactivation mainly affected three specific functional groups including proteins implicated in cell division. The absence of Elongator results in a delay in mitosis onset and cytokinesis defects. We demonstrate that the kinase Cdr2, which is a central regulator of mitosis and cytokinesis, is under translational control by Elongator due to the Lysine codon usage bias of the cdr2 coding sequence. These findings uncover a mechanism by which the codon usage, coupled to tRNA modifications, fundamentally contributes to gene expression and cellular functions.

Linking salinity stress tolerance with tissue-specific Na+ sequestration in wheat roots

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Honghong eWu

2015-02-01

Full Text Available Salinity stress tolerance is a physiologically complex trait that is conferred by the large array of interacting mechanisms. Among these, vacuolar Na+ sequestration has always been considered as one of the key components differentiating between sensitive and tolerant species and genotypes. However, vacuolar Na+ sequestration has been rarely considered in the context of the tissue-specific expression and regulation of appropriate transporters contributing to Na+ removal from the cytosol. In this work, six bread wheat varieties contrasting in their salinity tolerance (three tolerant and three sensitive were used to understand the essentiality of vacuolar Na+ sequestration between functionally different root tissues, and link it with the overall salinity stress tolerance in this species. Roots of 4-d old wheat seedlings were treated with 100 mM NaCl for 3 days, and then Na+ distribution between cytosol and vacuole was quantified by CoroNa Green fluorescent dye imaging. Our major observations were as follows: 1 salinity stress tolerance correlated positively with vacuolar Na+ sequestration ability in the mature root zone but not in the root apex; 2 Contrary to expectations, cytosolic Na+ levels in root meristem were significantly higher in salt tolerant than sensitive group, while vacuolar Na+ levels showed an opposite trend. These results are interpreted as meristem cells playing a role of the salt sensor; 3 No significant difference in the vacuolar Na+ sequestration ability was found between sensitive and tolerant group in either transition or elongation zones; 4 The overall Na+ accumulation was highest in the elongation zone, suggesting its role in osmotic adjustment and turgor maintenance required to drive root expansion growth. Overall, the reported results suggest high tissue-specificity of Na+ uptake, signalling, and sequestration in wheat root. The implications of these findings for plant breeding for salinity stress tolerance are discussed.

Growth and Anatomical Parameters of Adventitious Roots Formed on Mung Bean Hypocotyls Are Correlated with Galactoglucomannan Oligosaccharides Structure

Directory of Open Access Journals (Sweden)

K. Kollárová

2012-01-01

Full Text Available The effect of galactoglucomannan oligosaccharides (GGMOs compared with chemically modified oligosaccharides, GGMOs-g (with reduced number of D-galactose side chains and GGMOs-r (with reduced reducing ends on mung bean (Vigna radiata (L. Wilczek adventitious roots formation, elongation, and anatomical structure have been studied. All types of oligosaccharides influenced adventitious root formation in the same way: stimulation in the absence of exogenous auxin and inhibition in the presence of exogenous auxin. Both reactions are probably related with the presence/content of endogenous auxin in plant cuttings. However, the adventitious root length was inhibited by GGMOs both in the absence as well as in the presence of auxin (IBA or NAA, while GGMOs-g inhibition was significantly weaker compared with GGMOs. GGMOs-r were without significant difference on both processes, compared with GGMOs. GGMOs affected not only the adventitious root length but also their anatomy in dependence on the combination with certain type of auxin. The oligosaccharides influenced cortical cells division, which was reflected in the cortex area and in the root diameter. All processes followed were dependent on oligosaccharides chemical structure. The results suggest also that GGM-derived oligosaccharides may play an important role in adventitious roots elongation but not in their formation.

Helical Root Buckling: A Transient Mechanism for Stiff Interface Penetration

Science.gov (United States)

Silverberg, Jesse; Noar, Roslyn; Packer, Michael; Harrison, Maria; Cohen, Itai; Henley, Chris; Gerbode, Sharon

2011-03-01

Tilling in agriculture is commonly used to loosen the topmost layer of soil and promote healthy plant growth. As roots navigate this mechanically heterogeneous environment, they encounter interfaces between the compliant soil and the underlying compacted soil. Inspired by this problem, we used 3D time-lapse imaging of Medicago Truncatula plants to study root growth in two-layered transparent hydrogels. The layers are mechanically distinct; the top layer is more compliant than the bottom. We observe that the roots form a transient helical structure as they attempt to penetrate the bi-layer interface. Interpreting this phenotype as a form of buckling due to root elongation, we measured the helix size as a function of the surrounding gel modulus. Our measurements show that by twisting the root tip during growth, the helical structure recruits the surrounding medium for an enhanced penetration force allowing the plants access to the lower layer of gel.

Trade studies of plasma elongation for next-step tokamaks

International Nuclear Information System (INIS)

Galambos, J.D.; Strickler, D.J.; Peng, Y.K.M.; Reid, R.L.

1988-09-01

The effect of elongation on minimum-cost devices is investigated for elongations ranging from 2 to 3. The analysis, carried out with the TETRA tokamak systems code, includes the effects of elongation on both physics (plasma beta limit) and engineering (poloidal field coil currents) issues. When ignition is required, the minimum cost occurs for elongations from 2.3 to 2.9, depending on the plasma energy confinement scaling used. Scalings that include favorable plasma current dependence and/or degradation with fusion power tend to have minimum cost at higher elongation (2.5-2.9); scalings that depend primarily on size result in lower elongation (/approximately/2.3) for minimum cost. For design concepts that include steady-state current-driven operation, minimum cost occurs at an elongation of 2.3. 12 refs., 13 figs

Coordination of growth in root and shoot apices by AIL/PLT transcription factors

NARCIS (Netherlands)

Scheres, Ben; Krizek, Beth A.

2018-01-01

Growth at the root tip and organ generation at the shoot tip depend on the proper functioning of apical meristems and the transitioning of meristematic cell descendants from a proliferating state to cell elongation and differentiation. Members of the AINTEGUMENTA-LIKE/PLETHORA (AIL/PLT)

Nitric oxide plays a central role in determining lateral root development in tomato.

Science.gov (United States)

Correa-Aragunde, Natalia; Graziano, Magdalena; Lamattina, Lorenzo

2004-04-01

Nitric oxide (NO) is a bioactive molecule that functions in numerous physiological processes in plants, most of them involving cross-talk with traditional phytohormones. Auxin is the main hormone that regulates root system architecture. In this communication we report that NO promotes lateral root (LR) development, an auxin-dependent process. Application of the NO donor sodium nitroprusside (SNP) to tomato ( Lycopersicon esculentum Mill.) seedlings induced LR emergence and elongation in a dose-dependent manner, while primary root (PR) growth was diminished. The effect is specific for NO since the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (CPTIO) blocked the action of SNP. Depletion of endogenous NO with CPTIO resulted in the complete abolition of LR emergence and a 40% increase in PR length, confirming a physiological role for NO in the regulation of root system growth and development. Detection of endogenous NO by the specific probe 4,5-diaminofluorescein diacetate (DAF-2 DA) revealed that the NO signal was specifically located in LR primordia during all stages of their development. In another set of experiments, SNP was able to promote LR development in auxin-depleted seedlings treated with the auxin transport inhibitor N-1-naphthylphthalamic acid (NPA). Moreover, it was found that LR formation induced by the synthetic auxin 1-naphthylacetic acid (NAA) was prevented by CPTIO in a dose-dependent manner. All together, these results suggest a novel role for NO in the regulation of LR development, probably operating in the auxin signaling transduction pathway.

Elongational viscosity of monodisperse and bidisperse polystyrene melts

DEFF Research Database (Denmark)

Nielsen, Jens Kromann; Rasmussen, Henrik K.; Hassager, Ole

2006-01-01

The start-up and steady uniaxial elongational viscosity have been measured for two monodisperse polystyrene melts with molecular weights of 52 and 103 kg/mole, and for three bidisperse polystyrene melts. The monodisperse melts show a maximum in the steady elongational viscosity vs. the elongational...

Distinct modes of adventitious rooting in Arabidopsis thaliana.

Science.gov (United States)

Correa, L da Rocha; Troleis, J; Mastroberti, A A; Mariath, J E A; Fett-Neto, A G

2012-01-01

The literature describes different rooting protocols for Arabidopsis thaliana as models to study adventitious rooting, and results are generally perceived as comparable. However, there is a lack of investigations focusing on the distinct features, advantages and limitations of each method in the study of adventitious rooting with both wild-type (WT) ecotypes and their respective mutants. This investigation was undertaken to evaluate the adventitious rooting process in three different experimental systems, all using A. thaliana, analysing the same rooting parameters after transient exposure to auxin (indole-3-acetic acid) and control conditions: excised leaves, de-rooted plants and etiolated seedlings. The founding tissues and sites of origin of roots differed depending on the system used, whereas all rooting patterns were of the direct type (i.e., without callus formation). None of the systems had an absolute requirement for exogenous auxin, although rooting was enhanced by this phytohormone, with the exception of de-rooted plants, which had adventitious rooting strongly inhibited by exogenous auxin. Root elongation was much favoured in isolated leaves. Auxin-overproducing mutants could not be used in the detached leaf system due to precocious senescence; in the de-rooted plant system, these mutants had a WT-like rooting response, whereas the expression of the 'rooty' phenotype was only evident in the etiolated seedling system. Adventitious rooting of etiolated WT seedlings in the presence of exogenous auxin was inhibited by exogenous flavonoids, which act as auxin transport inhibitors; surprisingly, the flavonoid-deficient mutant chs had a lower rooting response compared to WT. Although Arabidopsis is an excellent model system to study adventitious rooting, physiological and developmental responses differed significantly, underlining the importance of avoiding data generalisation on rooting responses derived from different experimental systems with this species. �

Quantification of abscisic acid in a single maize root

International Nuclear Information System (INIS)

Reymond, P.; Saugy, M.; Pilet, P.E.

1987-01-01

Quantitative analyses of abscisic acid in the elongating zone of a single maize root (Zea mays L. cv LG 11) were performed by gas chromatography-mass spectrometry using negative chemical ion ionization. Data showed that the more abscisic acid, the slower the growth, but a large dispersion of individual values was observed. We assume that abscisic acid is perhaps not correlated only to the growth rate. (author)

Lettuce seed germination and root elongation toxicity evaluation of the F-Area seepline soils

International Nuclear Information System (INIS)

Nelson, E.A.; Westbury, H.M. Jr.

1994-09-01

This study is a continuation of similar studies conducted by Easton and Murphy (1993) and Loehle (1990). The objectives of these studies are to: (1) assess the toxicity of the water-soluble constituents of soil in a seepline adjacent to the F-Area Seepage Basins and (2) evaluate the effectiveness of rainwater movements in reducing the toxicity of the soil. Soils from the F-Area seepline that were found to inhibit lettuce seed germination and radical elongation in 1990 were not found to be significantly different from soils from an uncontaminated control site in this test. After six washings of the soil, the toxicity of the leachate was comparable to that of de-ionized water. This indicates that natural water movements may have rendered the F-Area seepline soils less toxic to lettuce seedlings than in previous tests

Effect of fluorine and of beta-indolacetic acid on the respiration of root tissue

Energy Technology Data Exchange (ETDEWEB)

Pilet, P E

1964-01-01

The auxin, beta-indolacetic acid, (BIAA) inhibited the elongation of Lens culinaris roots at all concentrations. At high concentrations fluoride had an inhibitor effect, but it had a stimulatory effect on root growth at low concentrations. BIAA mildly stimulated respiration at low concentrations and inhibited oxygen absorption at high concentrations. At concentrations stimulating respiration fluoride was found to reduce these stimulating effects caused by BIAA. Therefore, fluoride and BIAA acted as antagonists in their effect on respiration.

Root canal therapy for the prevention of osteonecrosis of the jaws: an evidence-based clinical update.

Science.gov (United States)

Kyrgidis, Athanassios; Arora, Amit; Lyroudia, Kleoniki; Antoniades, Konstantinos

2010-12-01

Osteonecrosis of the jaws is an adverse effect of bone preservation treatment. There is a sufficient body of evidence to associate osteonecrosis of the jaws development with dental extractions and trauma caused from ill-fitting dentures. In this review, we critically appraise available evidence about the clinical efficacy of root canal therapy in patients receiving bisphosphonates.We review a series of theories to explain why endodontic treatment is a safe clinical intervention to prevent osteonecrosis of the jaws in patients receiving bisphosphonates. Root canal therapy could postpone or even eradicate the need for dental extractions of carious teeth in patients on bisphosphonates who may develop osteonecrosis of the jaws. Patients receiving bisphosphonates should be offered the full range of preventive care to reduce their risk to both dental caries and periodontal disease, so that the need for both endodontic therapy and dental extractions will be reduced. Implementing such a strategy would require both practitioner and patient education through the combined efforts of medical and dental societies. Such an approach is justified, as the risk of compromising the oral health of patients on bisphosphonates undertaking endodontic treatment is negligible compared with the benefit from avoiding dental extractions.

A late embryogenesis abundant protein HVA1 regulated by an inducible promoter enhances root growth and abiotic stress tolerance in rice without yield penalty.

Science.gov (United States)

Chen, Yi-Shih; Lo, Shuen-Fang; Sun, Peng-Kai; Lu, Chung-An; Ho, Tuan-Hua D; Yu, Su-May

2015-01-01

Regulation of root architecture is essential for maintaining plant growth under adverse environment. A synthetic abscisic acid (ABA)/stress-inducible promoter was designed to control the expression of a late embryogenesis abundant protein (HVA1) in transgenic rice. The background of HVA1 is low but highly inducible by ABA, salt, dehydration and cold. HVA1 was highly accumulated in root apical meristem (RAM) and lateral root primordia (LRP) after ABA/stress treatments, leading to enhanced root system expansion. Water-use efficiency (WUE) and biomass also increased in transgenic rice, likely due to the maintenance of normal cell functions and metabolic activities conferred by HVA1 which is capable of stabilizing proteins, under osmotic stress. HVA1 promotes lateral root (LR) initiation, elongation and emergence and primary root (PR) elongation via an auxin-dependent process, particularly by intensifying asymmetrical accumulation of auxin in LRP founder cells and RAM, even under ABA/stress-suppressive conditions. We demonstrate a successful application of an inducible promoter in regulating the spatial and temporal expression of HVA1 for improving root architecture and multiple stress tolerance without yield penalty. © 2014 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

Responses of grapevine rootstocks to drought through altered root system architecture and root transcriptomic regulations.

Science.gov (United States)

Yıldırım, Kubilay; Yağcı, Adem; Sucu, Seda; Tunç, Sümeyye

2018-06-01

Roots are the major interface between the plant and various stress factors in the soil environment. Alteration of root system architecture (RSA) (root length, spread, number and length of lateral roots) in response to environmental changes is known to be an important strategy for plant adaptation and productivity. In light of ongoing climate changes and global warming predictions, the breeding of drought-tolerant grapevine cultivars is becoming a crucial factor for developing a sustainable viticulture. Root-trait modeling of grapevine rootstock for drought stress scenarios, together with high-throughput phenotyping and genotyping techniques, may provide a valuable background for breeding studies in viticulture. Here, tree grafted grapevine rootstocks (110R, 5BB and 41B) having differential RSA regulations and drought tolerance were investigated to define their drought dependent root characteristics. Root area, root length, ramification and number of root tips reduced less in 110R grafted grapevines compared to 5BB and 41B grafted ones during drought treatment. Root relative water content as well as total carbohydrate and nitrogen content were found to be much higher in the roots of 110R than it was in the roots of other rootstocks under drought. Microarray-based root transcriptome profiling was also conducted on the roots of these rootstocks to identify their gene regulation network behind drought-dependent RSA alterations. Transcriptome analysis revealed totally 2795, 1196 and 1612 differentially expressed transcripts at the severe drought for the roots of 110R, 5BB and 41B, respectively. According to this transcriptomic data, effective root elongation and enlargement performance of 110R were suggested to depend on three transcriptomic regulations. First one is the drought-dependent induction in sugar and protein transporters genes (SWEET and NRT1/PTR) in the roots of 110R to facilitate carbohydrate and nitrogen accumulation. In the roots of the same rootstock

How Can Science Education Foster Students' Rooting?

Science.gov (United States)

Østergaard, Edvin

2015-01-01

The question of how to foster rooting in science education points towards a double challenge; efforts to "prevent" (further) uprooting and efforts to "promote" rooting/re-rooting. Wolff-Michael Roth's paper discusses the uprooting/rooting pair of concepts, students' feeling of alienation and loss of fundamental sense of the…

ATFL elongation after Brostrom procedure: a biomechanical investigation.

Science.gov (United States)

Kirk, Kevin L; Campbell, John T; Guyton, Gregory P; Parks, Brent G; Schon, Lew C

2008-11-01

Elongation of ligaments during early mobilization after reconstruction may be associated with decreased stability. We evaluated elongation of the anterior talofibular ligament (ATFL) before and after lateral ligament reconstruction within a physiologic range of motion with protected and unprotected, isolated dorsiflexion/plantarflexion range of motion. Six fresh frozen cadaver legs were used with the ATFL meticulously dissected. A differential variable reluctance transducer (DVRT) was spaced to span the course of the ATFL using consistent placement points based on previous reports. Elongation was measured in a load frame with protected motion of 30 degrees plantarflexion and 10 degrees dorsiflexion for the intact and sectioned ATFL and for the repaired specimen with and without protected motion. The proximal DVRT anchor point was detached for sectioning and repair of the ATFL and replaced at the same position. Testing was 1000 cycles at 1 Hz for the repaired protected specimen and 10 cycles at 1 Hz for all other stages. Initial elongation in the unprotected, repaired group was significantly higher than initial elongation in the intact (p ankle after lateral ankle ligament reconstruction was not associated with elongation of the ATFL. The ATFL elongated significantly by comparison without protected dorsiflexion/plantarflexion. The study provides biomechanical support for the safety of early protected dorsiflexion/plantarflexion range of motion after Broström reconstruction.

Unique and Conserved Features of the Barley Root Meristem

Directory of Open Access Journals (Sweden)

Gwendolyn K. Kirschner

2017-07-01

Full Text Available Plant root growth is enabled by root meristems that harbor the stem cell niches as a source of progenitors for the different root tissues. Understanding the root development of diverse plant species is important to be able to control root growth in order to gain better performances of crop plants. In this study, we analyzed the root meristem of the fourth most abundant crop plant, barley (Hordeum vulgare. Cell division studies revealed that the barley stem cell niche comprises a Quiescent Center (QC of around 30 cells with low mitotic activity. The surrounding stem cells contribute to root growth through the production of new cells that are displaced from the meristem, elongate and differentiate into specialized root tissues. The distal stem cells produce the root cap and lateral root cap cells, while cells lateral to the QC generate the epidermis, as it is typical for monocots. Endodermis and inner cortex are derived from one common initial lateral to the QC, while the outer cortex cell layers are derived from a distinct stem cell. In rice and Arabidopsis, meristem homeostasis is achieved through feedback signaling from differentiated cells involving peptides of the CLE family. Application of synthetic CLE40 orthologous peptide from barley promotes meristem cell differentiation, similar to rice and Arabidopsis. However, in contrast to Arabidopsis, the columella stem cells do not respond to the CLE40 peptide, indicating that distinct mechanisms control columella cell fate in monocot and dicot plants.

Water Deficit and Abscisic Acid Cause Differential Inhibition of Shoot versus Root Growth in Soybean Seedlings : Analysis of Growth, Sugar Accumulation, and Gene Expression.

Science.gov (United States)

Creelman, R A; Mason, H S; Bensen, R J; Boyer, J S; Mullet, J E

1990-01-01

Roots often continue to elongate while shoot growth is inhibited in plants subjected to low-water potentials. The cause of this differential response to water deficit was investigated. We examined hypocotyl and root growth, polysome status and mRNA populations, and abscisic acid (ABA) content in etiolated soybean (Glycine max [L.] Merr. cv Williams) seedlings whose growth was inhibited by transfer to low-water potential vermiculite or exogenous ABA. Both treatments affected growth and dry weight in a similar fashion. Maximum inhibition of hypocotyl growth occurred when internal ABA levels (modulated by ABA application) reached the endogenous level found in the elongating zone of seedlings grown in water-deficient vermiculite. Conversely, root growth was affected to only a slight extent in low-water potential seedlings and by most ABA treatments (in some, growth was promoted). In every seedling section examined, transfer of seedlings into low-water potential vermiculite caused ABA levels to increase approximately 5- to 10-fold over that found in well-watered seedlings. Changes in soluble sugar content, polysome status, and polysome mRNA translation products seen in low-water potential seedlings did not occur with ABA treatments sufficient to cause significant inhibition of hypocotyl elongation. These data suggest that both variation in endogenous ABA levels, and differing sensitivity to ABA in hypocotyls and roots can modulate root/shoot growth ratios. However, exogenous ABA did not induce changes in sugar accumulation, polysome status, and mRNA populations seen after transfer into low-water potential vermiculite.

Phytotoxic grass residues reduce germination and initial root growth of ponderosa pine

Science.gov (United States)

W. J. Rietveld

1975-01-01

Extracts of green foliage of Arizona fescue and mountain muhly significantly reduced germination of ponderosa pine seeds, and retarded speed of elongation and mean radicle length. Three possible routes of release of the inhibitor were investigated: (1) leaching from live foliage, (2) root exudation, and (3) overwinter leaching from dead residues. The principal route...

Genetic analysis of the gravitropic set-point angle in lateral roots of arabidopsis

Science.gov (United States)

Mullen, J. L.; Hangarter, R. P.

2003-05-01

Research on gravity responses in plants has mostly focused on primary roots and shoots, which typically orient to a vertical orientation. However, the distribution of lateral organs and their characteristically non-vertical growth orientation are critical for the determination of plant form. For example, in Arabidopsis, when lateral roots emerge from the primary root, they grow at a nearly horizontal orientation. As they elongate, the roots slowly curve until they eventually reach a vertical orientation. The regulation of this lateral root orientation is an important component affecting overall root system architecture. We found that this change in orientation is not simply due to the onset of gravitropic competence, as non-vertical lateral roots are capable of both positive and negative gravitropism. Thus, the horizontal growth of new lateral roots appears to be determined by what is called the gravitropic set-point angle (GSA). This developmental control of the GSA of lateral roots in Arabidopsis provides a useful system for investigating the components involved in regulating gravitropic responses. Using this system, we have identified several Arabidopsis mutants that have altered lateral root orientations but maintain normal primary root orientation.

Statistical modeling of nitrogen-dependent modulation of root system architecture in Arabidopsis thaliana.

Science.gov (United States)

Araya, Takao; Kubo, Takuya; von Wirén, Nicolaus; Takahashi, Hideki

2016-03-01

Plant root development is strongly affected by nutrient availability. Despite the importance of structure and function of roots in nutrient acquisition, statistical modeling approaches to evaluate dynamic and temporal modulations of root system architecture in response to nutrient availability have remained as widely open and exploratory areas in root biology. In this study, we developed a statistical modeling approach to investigate modulations of root system architecture in response to nitrogen availability. Mathematical models were designed for quantitative assessment of root growth and root branching phenotypes and their dynamic relationships based on hierarchical configuration of primary and lateral roots formulating the fishbone-shaped root system architecture in Arabidopsis thaliana. Time-series datasets reporting dynamic changes in root developmental traits on different nitrate or ammonium concentrations were generated for statistical analyses. Regression analyses unraveled key parameters associated with: (i) inhibition of primary root growth under nitrogen limitation or on ammonium; (ii) rapid progression of lateral root emergence in response to ammonium; and (iii) inhibition of lateral root elongation in the presence of excess nitrate or ammonium. This study provides a statistical framework for interpreting dynamic modulation of root system architecture, supported by meta-analysis of datasets displaying morphological responses of roots to diverse nitrogen supplies. © 2015 Institute of Botany, Chinese Academy of Sciences.

The combined use of Er,Cr:YSGG laser and fluoride to prevent root dentin demineralization

Directory of Open Access Journals (Sweden)

Vinícius Rangel GERALDO-MARTINS

2014-10-01

Full Text Available The use of erbium lasers to prevent caries in enamel has shown positive results. However, it is not known if Er,Cr:YSGG laser can also be used to increase acid resistance of root dentine, which is another dental tissue susceptible to the action of cariogenic bacteria. Objective: To analyze the effects of the Er,Cr:YSGG laser (λ=2.78 μm, 20 Hz irradiation associated with 2% neutral sodium fluoride (NaF to prevent root dentin demineralization. Material and Methods: One hundred human root dentin samples were divided into 10 groups (G and treated as follows: G1: no treatment; G2: NaF; G3: laser (4.64 J/cm2 with water cooling (WC=5.4 mL/min; G4: laser (4.64 J/cm2 without WC; G5: laser (8.92 J/cm2 with WC; G6: laser (8.92 J/cm2 without WC; G7: laser (4.64 J/cm2 with WC and NaF; G8: laser (4.64 J/cm2 without WC and NaF; G9: laser (8.92 J/cm2 with WC and NaF; G10: laser (8.92 J/cm2 without WC and NaF. The NaF gel was applied alone or after 4 min of irradiation. After 14 days of acid challenge, the samples were sectioned and the Knoop microhardness (KHN test was done at different depths (30, 60, 90 and 120 μm from the outer dentin surface. Data were analyzed by one-way ANOVA and Fisher’s test (α=5%. Results: The results showed that G8 and G10 presented higher KHN than the G1 for the depths of 30 and 60 μm, indicating an increase of the acid resistance of the dentin in up to 35% (p<0.05. Conclusions: The use of Er,Cr:YSGG laser irradiation at 4.64 J/ cm2 and 8.92 J/cm2 without water cooling and associated with 2% NaF can increase the acid resistance of human root dentin.

Stability of tokamaks with elongated cross section

International Nuclear Information System (INIS)

An, C.H.; Bateman, G.

1978-08-01

Fixed boundary n = 1 MHD instabilities are studied computationally as a function of diamagnetism (β/sub pol/) and current profile in elongated toroidal equilibria (1 2) or a diamagnetic plasma (β/sub pol/ > 1) with only a mildly elongated cross section

Characterization of heavy metal-resistant endophytic bacteria from rape (Brassica napus) roots and their potential in promoting the growth and lead accumulation of rape

International Nuclear Information System (INIS)

Sheng Xiafang; Xia Juanjuan; Jiang Chunyu; He Linyan; Qian Meng

2008-01-01

Two lead (Pb)-resistant endophytic bacteria were isolated from rape roots grown in heavy metal-contaminated soils and characterized. A pot experiment was conducted for investigating the capability of the two isolates to promote the growth and Pb uptake of rape from Pb-amended soil. The two isolates were identified as Pseudomonas fluorescens G10 and Microbacterium sp. G16 based on the 16S rDNA gene sequence analysis. Strains G10 and G16 exhibited different multiple heavy metal and antibiotic resistance characteristics and increased water-soluble Pb in solution and in Pb-added soil. Root elongation assays demonstrated increases in root elongation of inoculated rape seedlings compared to the control plants. Strain G16 produced indole acetic acid, siderophores and 1-aminocyclopropane-1-carboxylate deaminase. Increases in biomass production and total Pb uptake in the bacteria-inoculated plants were obtained compared to the control. The two strains could colonize the root interior and rhizosphere soil of rape after root inoculation. - Heavy metal-resistant endophytic bacteria from rape have the potential of promoting the growth and lead uptake of rape

Inheritance and gene expression of a root-growth inhibiting mutant in rice (Oryza sativa L.)

International Nuclear Information System (INIS)

Kitano, H.; Futsuhara, Y.

1990-01-01

Full text: A root-growth inhibiting mutant was induced in the dwarf mutant line, 'Fukei 71', through ethylene-imine. The mutant is characterised by the excessive inhibition of both seminal and crown roots elongation just after germination, although its shoots grow nearly normal. To study the genetics, the mutant was crossed with its original line 'Fukei 71' and some other normal cultivars. Results show that the root-growth inhibition is controlled by a recessive gene (rt), independent of the dwarf gene, d-50(t) locus in Fukei 71. For elucidating the gene action on root morphogenesis, histological and cytological experiments were carried out using a longitudinal and transverse thin section of seminal and/or crown root tips. Observations suggest that the rt gene affects the normal formation of the epidermal system which is differentiated from the protoderm of the root apical meristem. (author)

Automated electronic reminders to prevent miscommunication among primary medical, surgical and anaesthesia providers: a root cause analysis.

Science.gov (United States)

Freundlich, Robert E; Grondin, Louise; Tremper, Kevin K; Saran, Kelly A; Kheterpal, Sachin

2012-10-01

In this case report, the authors present an adverse event possibly caused by miscommunication among three separate medical teams at their hospital. The authors then discuss the hospital's root cause analysis and its proposed solutions, focusing on the subsequent hospital-wide implementation of an automated electronic reminder for abnormal laboratory values that may have helped to prevent similar medical errors.

High n ballooning modes in highly elongated tokamaks

International Nuclear Information System (INIS)

An, C.H.; Bateman, G.

1980-02-01

An analytic study of stability against high n ballooning modes in highly elongated axisymmetric plasmas is presented and compared with computational results. From the equation for the marginal pressure gradient, it is found that the local shear plays an important role on the stability of elongated and shifted plasma, and that high elongation deteriorates the stability by decreasing the stabilizing effects of field line bending and local shear. The net contribution of the local shear to stability decreases with elongation and shift for strongly ballooning modes (eigenfunctions strongly localized near the outer edge of the toroidal flux surfaces) but increases for interchange modes (eigenfunctions more uniform along the flux surfaces). The computational study of high n ballooning modes in a highly elongated plasma reveals that lowering the aspect ratio and broadening the pressure profile enhance the marginal beta for β/sub p/ less than unity but severely reduce the marginal beta for β/sub p/ larger than unity

Tonoplast aquaporins facilitate lateral root emergence

DEFF Research Database (Denmark)

Reinhardt, Hagen; Hachez, Charles; Bienert, Manuela Désirée

2016-01-01

Aquaporins (AQPs) are water channels allowing fast and passive diffusion of water across cell membranes. It was hypothesized that AQPs contribute to cell elongation processes by allowing water influx across the plasma membrane and the tonoplast to maintain adequate turgor pressure. Here, we report...... mutants showed no or minor reduction in growth of the main root. This phenotype was due to the retardation of LRP emergence. Live cell imaging revealed that tight spatiotemporal control of TIP abundance in the tonoplast of the different LRP cells is pivotal to mediating this developmental process. While...... lateral root emergence is correlated to a reduction of AtTIP1;1 and AtTIP1;2 protein levels in LRPs, expression of AtTIP2;1 is specifically needed in a restricted cell population at the base, then later at the flanks, of developing LRPs. Interestingly, the LRP emergence phenotype of the triple tip mutants...

Complex Regulation of Prolyl-4-Hydroxylases Impacts Root Hair Expansion

DEFF Research Database (Denmark)

Velasquez, Silvia M; Ricardi, Martiniano M; Poulsen, Christian Peter

2015-01-01

Root hairs are single cells that develop by tip growth, a process shared with pollen tubes, axons, and fungal hyphae. However, structural plant cell walls impose constraints to accomplish tip growth. In addition to polysaccharides, plant cell walls are composed of hydroxyproline-rich glycoproteins......5, and to a lesser extent P4H2 and P4H13, are pivotal for root hair tip growth. Second, we demonstrate that P4H5 has in vitro preferred specificity for EXT substrates rather than for other HRGPs. Third, by P4H promoter and protein swapping approaches, we show that P4H2 and P4H13 have interchangeable...... peptidyl-proline hydroxylation on EXTs, and possibly in other HRGPs, is required for proper cell wall self-assembly and hence root hair elongation in Arabidopsis thaliana....

Pharmacognostic study of Lantana camara Linn. root

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Dinesh Kumar

2012-05-01

Full Text Available Objective: The study was carried out to perform the pharmacognostic evaluation of Lantana camara Linn. root. Method: The pharmacognostic evaluation was done in terms of organoleptic, macro-microscopy, fluorescence analysis and physicochemical parameters. Results: The characteristic macroscopic features showed that the root consists of 25-40 cm long, 0.2-4.0 cm thick pieces which are usually branched, shallow, tough, creamish-brown externally, outer surface rough due to longitudinal wrinkles, with hard fracture, characteristic odour and pungent taste. The main microscopic characters of the root shows exfoliating cork, consisting of about 10-15 rows of tangentially elongated, thick-walled cells followed by cortex consisting of polygonal parenchymatous cells, a few containing rhomboidal shaped calcium oxalate crystals. Endodermis consists of 3-4 layers of non-lignified, thick-walled rounded parenchymatous cells followed by a single layer of non-lignified pericycle. Phloem, a wide zone of xylem consisting of lignified pitted vessels and bi-to triseriate medullary rays are also present. Proximate physicochemical analysis of the root power showed loss on drying, total ash, water soluble ash, sulphated ash values as 0.52, 4.26, 3.8 and 5.8 % w/w respectively. Successive extraction of the root powder with petroleum ether, chloroform, alcohol, water yielded 0.19, 0.35, 2.19 and 2.0 % w/w respectively. Fluorescence study imparted characteristic colors to the root powder when observed under visible, short and long wavelength light. Conclusions: Various pharmacognostic parameters evaluated in this study helps in identification and standardization of Lantana camara L. root in crude form.

Phosphate-dependent root system architecture responses to salt stress

KAUST Repository

Kawa, Dorota; Julkowska, Magdalena; Montero Sommerfeld, Hector; Horst, Anneliek ter; Haring, Michel A; Testerink, Christa

2016-01-01

Nutrient availability and salinity of the soil affect growth and development of plant roots. Here, we describe how phosphate availability affects root system architecture (RSA) of Arabidopsis and how phosphate levels modulate responses of the root to salt stress. Phosphate (Pi) starvation reduced main root length and increased the number of lateral roots of Arabidopsis Col-0 seedlings. In combination with salt, low Pi dampened the inhibiting effect of mild salt stress (75mM) on all measured RSA components. At higher NaCl concentrations, the Pi deprivation response prevailed over the salt stress only for lateral root elongation. The Pi deprivation response of lateral roots appeared to be oppositely affected by abscisic acid (ABA) signaling compared to the salt stress response. Natural variation in the response to the combination treatment of salt and Pi starvation within 330 Arabidopsis accessions could be grouped into four response patterns. When exposed to double stress, in general lateral roots prioritized responses to salt, while the effect on main root traits was additive. Interestingly, these patterns were not identical for all accessions studied and multiple strategies to integrate the signals from Pi deprivation and salinity were identified. By Genome Wide Association Mapping (GWAS) 13 genomic loci were identified as putative factors integrating responses to salt stress and Pi starvation. From our experiments, we conclude that Pi starvation interferes with salt responses mainly at the level of lateral roots and that large natural variation exists in the available genetic repertoire of accessions to handle the combination of stresses.

Phosphate-dependent root system architecture responses to salt stress

KAUST Repository

Kawa, Dorota

2016-05-20

Nutrient availability and salinity of the soil affect growth and development of plant roots. Here, we describe how phosphate availability affects root system architecture (RSA) of Arabidopsis and how phosphate levels modulate responses of the root to salt stress. Phosphate (Pi) starvation reduced main root length and increased the number of lateral roots of Arabidopsis Col-0 seedlings. In combination with salt, low Pi dampened the inhibiting effect of mild salt stress (75mM) on all measured RSA components. At higher NaCl concentrations, the Pi deprivation response prevailed over the salt stress only for lateral root elongation. The Pi deprivation response of lateral roots appeared to be oppositely affected by abscisic acid (ABA) signaling compared to the salt stress response. Natural variation in the response to the combination treatment of salt and Pi starvation within 330 Arabidopsis accessions could be grouped into four response patterns. When exposed to double stress, in general lateral roots prioritized responses to salt, while the effect on main root traits was additive. Interestingly, these patterns were not identical for all accessions studied and multiple strategies to integrate the signals from Pi deprivation and salinity were identified. By Genome Wide Association Mapping (GWAS) 13 genomic loci were identified as putative factors integrating responses to salt stress and Pi starvation. From our experiments, we conclude that Pi starvation interferes with salt responses mainly at the level of lateral roots and that large natural variation exists in the available genetic repertoire of accessions to handle the combination of stresses.

Ubiquitylation and degradation of elongating RNA polymerase II

DEFF Research Database (Denmark)

Wilson, Marcus D; Harreman, Michelle; Svejstrup, Jesper Q

2013-01-01

During its journey across a gene, RNA polymerase II has to contend with a number of obstacles to its progression, including nucleosomes, DNA-binding proteins, DNA damage, and sequences that are intrinsically difficult to transcribe. Not surprisingly, a large number of elongation factors have....... In this review, we describe the mechanisms and factors responsible for the last resort mechanism of transcriptional elongation. This article is part of a Special Issue entitled: RNA polymerase II Transcript Elongation....

MreB-Dependent Inhibition of Cell Elongation during the Escape from Competence in Bacillus subtilis.

Science.gov (United States)

Mirouze, Nicolas; Ferret, Cécile; Yao, Zhizhong; Chastanet, Arnaud; Carballido-López, Rut

2015-06-01

During bacterial exponential growth, the morphogenetic actin-like MreB proteins form membrane-associated assemblies that move processively following trajectories perpendicular to the long axis of the cell. Such MreB structures are thought to scaffold and restrict the movement of peptidoglycan synthesizing machineries, thereby coordinating sidewall elongation. In Bacillus subtilis, this function is performed by the redundant action of three MreB isoforms, namely MreB, Mbl and MreBH. mreB and mbl are highly transcribed from vegetative promoters. We have found that their expression is maximal at the end of exponential phase, and rapidly decreases to a low basal level upon entering stationary phase. However, in cells developing genetic competence, a stationary phase physiological adaptation, expression of mreB was specifically reactivated by the central competence regulator ComK. In competent cells, MreB was found in complex with several competence proteins by in vitro pull-down assays. In addition, it co-localized with the polar clusters formed by the late competence peripheral protein ComGA, in a ComGA-dependent manner. ComGA has been shown to be essential for the inhibition of cell elongation characteristic of cells escaping the competence state. We show here that the pathway controlling this elongation inhibition also involves MreB. Our findings suggest that ComGA sequesters MreB to prevent cell elongation and therefore the escape from competence.

Planar Elongation Measurements on Soft Elastomers

DEFF Research Database (Denmark)

Jensen, Mette Krog; Skov, Anne Ladegaard; Rasmussen, Henrik K.

2009-01-01

A new fixture to the filament stretch rheometer (FSR) has been developed to measure planar elongation of soft polymeric networks. To validate this new technique, soft polymeric networks of poly(propyleneoxide) (PPO) were investigated during deformation.......A new fixture to the filament stretch rheometer (FSR) has been developed to measure planar elongation of soft polymeric networks. To validate this new technique, soft polymeric networks of poly(propyleneoxide) (PPO) were investigated during deformation....

Investigation of Lab Fire Prevention Management System of Combining Root Cause Analysis and Analytic Hierarchy Process with Event Tree Analysis

Directory of Open Access Journals (Sweden)

Cheng-Chan Shih

2016-01-01

Full Text Available This paper proposed a new approach, combining root cause analysis (RCA, analytic hierarchy process (AHP, and event tree analysis (ETA in a loop to systematically evaluate various laboratory safety prevention strategies. First, 139 fire accidents were reviewed to identify the root causes and draw out prevention strategies. Most fires were caused due to runaway reactions, operation error and equipment failure, and flammable material release. These mostly occurred in working places of no prompt fire protection. We also used AHP to evaluate the priority of these strategies and found that chemical fire prevention strategy is the most important control element, and strengthening maintenance and safety inspection intensity is the most important action. Also together with our surveys results, we proposed that equipment design is also critical for fire prevention. Therefore a technical improvement was propounded: installing fire detector, automatic sprinkler, and manual extinguisher in the lab hood as proactive fire protections. ETA was then used as a tool to evaluate laboratory fire risks. The results indicated that the total risk of a fire occurring decreases from 0.0351 to 0.0042 without/with equipment taking actions. Establishing such system can make Environment, Health and Safety (EH&S office not only analyze and prioritize fire prevention policies more practically, but also demonstrate how effective protective equipment improvement can achieve and the probabilities of the initiating event developing into a serious accident or controlled by the existing safety system.

The preventive Control of White Root Rot Disease in Small Holder Rubber Plantation Using Botanical, Biological and Chemical Agents

Directory of Open Access Journals (Sweden)

Joko Prasetyo

2014-03-01

Full Text Available The preventive control of white root rot disease in small holder plantation using botanical, biological, and chemical agents. A field and laboratory experiment were conducted from June 2008 to December 2009 in Panumangan, Tulang Bawang - Lampung. The  field experiment was intended to evaluate the effect of  botanical plants (Alpinia galanga, Sansiviera auranthii, and Marantha arundinacea, biological agents (organic matter and Trichoderma spp., and chemical agents (lime and natural sulphur on the incidence of white root rot disease and population of some soil microbes. The laboratory experiment was conducted  to observe the mechanism of botanical agents  in controlling white root rot disease. In the field experiment, the treatments were applied  in the experimental plot with cassava plant infection as the indicator. The variables  examined were the incidence of  white root rot and population of soil microbes. In the laboratory experiment, culture of R. microporus was grown in PDA containing root exudate of the antagonistic plant (botanical agent. The variable examined was colony diameter of R. microporus growing in the PDA plates. The results of the  field experiment  showed that planting of the botanical agents, and application of Trichoderma spp., as well as natural sulphur, decreased the incidence of white root rot disease. The effectiveness of M. arundinacea and Trichoderma spp. was comparable to natural  sulphur. The laboratory experiment showed only root exudate of  A. galanga and  S. auranthii that were significantly inhibit the growth of R. microporus.

Phytotoxicity of nanoparticles: Inhibition of seed germination and root growth

Energy Technology Data Exchange (ETDEWEB)

Lin Daohui [Department of Environmental Science, Zhejiang University, Hangzhou 310028 (China); Department of Plant, Soil and Insect Sciences, University of Massachusetts, Stockbridge Hall, Amherst, MA 01003 (United States); Xing Baoshan [Department of Plant, Soil and Insect Sciences, University of Massachusetts, Stockbridge Hall, Amherst, MA 01003 (United States)], E-mail: bx@pssci.umass.edu

2007-11-15

Plants need to be included to develop a comprehensive toxicity profile for nanoparticles. Effects of five types of nanoparticles (multi-walled carbon nanotube, aluminum, alumina, zinc, and zinc oxide) on seed germination and root growth of six higher plant species (radish, rape, ryegrass, lettuce, corn, and cucumber) were investigated. Seed germination was not affected except for the inhibition of nanoscale zinc (nano-Zn) on ryegrass and zinc oxide (nano-ZnO) on corn at 2000 mg/L. Inhibition on root growth varied greatly among nanoparticles and plants. Suspensions of 2000 mg/L nano-Zn or nano-ZnO practically terminated root elongation of the tested plant species. Fifty percent inhibitory concentrations (IC{sub 50}) of nano-Zn and nano-ZnO were estimated to be near 50 mg/L for radish, and about 20 mg/L for rape and ryegrass. The inhibition occurred during the seed incubation process rather than seed soaking stage. These results are significant in terms of use and disposal of engineered nanoparticles. - Engineered nanoparticles can inhibit the seed germination and root growth.

Phytotoxicity of nanoparticles: Inhibition of seed germination and root growth

International Nuclear Information System (INIS)

Lin Daohui; Xing Baoshan

2007-01-01

Plants need to be included to develop a comprehensive toxicity profile for nanoparticles. Effects of five types of nanoparticles (multi-walled carbon nanotube, aluminum, alumina, zinc, and zinc oxide) on seed germination and root growth of six higher plant species (radish, rape, ryegrass, lettuce, corn, and cucumber) were investigated. Seed germination was not affected except for the inhibition of nanoscale zinc (nano-Zn) on ryegrass and zinc oxide (nano-ZnO) on corn at 2000 mg/L. Inhibition on root growth varied greatly among nanoparticles and plants. Suspensions of 2000 mg/L nano-Zn or nano-ZnO practically terminated root elongation of the tested plant species. Fifty percent inhibitory concentrations (IC 50 ) of nano-Zn and nano-ZnO were estimated to be near 50 mg/L for radish, and about 20 mg/L for rape and ryegrass. The inhibition occurred during the seed incubation process rather than seed soaking stage. These results are significant in terms of use and disposal of engineered nanoparticles. - Engineered nanoparticles can inhibit the seed germination and root growth

Effect of cutting medium temperatures on rooting process and root primordium differentiation of hardwood cuttings of tetraploid robinia pseudoacacia cutting medium temperatures of tetraploid robinia pseudoacacia

International Nuclear Information System (INIS)

Ling, W.X.; Jine, Q.; Zhong, Z.

2014-01-01

In this study, to examine the effect of heat treatment on the rooting and root development of hardwood cuttings of the tetraploid Robinia pseudoacacia, cuttings of 1-year-old stems were taken from 3-year-old mother trees and treated with IBA solution (1000 mg/L) for 6 h, with water was as a control. Treated cuttings were rooted in heated or unheated nursery beds. Samples were collected on day ten after planting, and then for every five days. The bases of the cuttings were embedded in paraffin and sectioned before being examined under a microscope to determine whether there had been any morphological changes. We found no root primordia in the tissues of the hardwood cuttings of the tetraploid Robinia pseudoacacia before cutting. In the heated bed, adventitious roots originated from callus tissue and the junction between the pith rays and cortical parenchyma cells, and in the unheated bed, adventitious roots originated only from callus tissue. The rooting process involved callus formation, adventitious root formation and elongation; rooting occurred 5-7 days earlier in the heated cuttings than in the unheated ones, and rooting rates were significantly higher in the former 30 days and 50 days after cutting; the minimum effective accumulated temperatures for these three stages were 109.25 degree C, 211.68 degree C and 301.38 degree C, respectively. Our results revealed that heating the soil can promote adventitious root formation, speed up the rooting rate, and cut the propagation period of the tetraploid Robinia pseudoacacia. (author)

Elongation of Flare Ribbons

Energy Technology Data Exchange (ETDEWEB)

Qiu, Jiong; Longcope, Dana W. [Department of Physics, Montana State University, Bozeman MT (United States); Cassak, Paul A. [Department of Physics and Astronomy, West Virginia University, Morgantown WV (United States); Priest, Eric R. [School of Mathematics and Statistics, University of St. Andrews, Fife KY16 9SS, Scotland (United Kingdom)

2017-03-20

We present an analysis of the apparent elongation motion of flare ribbons along the polarity inversion line (PIL), as well as the shear of flare loops in several two-ribbon flares. Flare ribbons and loops spread along the PIL at a speed ranging from a few to a hundred km s{sup −1}. The shear measured from conjugate footpoints is consistent with the measurement from flare loops, and both show the decrease of shear toward a potential field as a flare evolves and ribbons and loops spread along the PIL. Flares exhibiting fast bidirectional elongation appear to have a strong shear, which may indicate a large magnetic guide field relative to the reconnection field in the coronal current sheet. We discuss how the analysis of ribbon motion could help infer properties in the corona where reconnection takes place.

Evaluation of Enterococcus faecalis adhesion, penetration, and method to prevent the penetration of Enterococcus faecalis into root cementum: Confocal laser scanning microscope and scanning electron microscope analysis.

Science.gov (United States)

Halkai, Rahul S; Hegde, Mithra N; Halkai, Kiran R

2016-01-01

To ascertain the role of Enterococcus faecalis in persistent infection and a possible method to prevent the penetration of E. faecalis into root cementum. One hundred and twenty human single-rooted extracted teeth divided into five groups. Group I (control): intact teeth, Group II: no apical treatment done, Group III divided into two subgroups. In Groups IIIa and IIIb, root apex treated with lactic acid of acidic and neutral pH, respectively. Group IV: apical root cementum exposed to lactic acid and roughened to mimic the apical resorption. Group V: apical treatment done same as Group IV and root-end filling done using mineral trioxide aggregate (MTA). Apical one-third of all samples immersed in E. faecalis broth for 8 weeks followed by bone morphogenetic protein and obturation and again immersed into broth for 8 weeks. Teeth split into two halves and observed under confocal laser scanning microscope and scanning electron microscope, organism identified by culture and polymerase chain reaction techniques. Adhesion and penetration was observed in Group IIIa and Group IV. Only adhesion in Group II and IIIB and no adhesion and penetration in Group I and V. Adhesion and penetration of E. faecalis into root cementum providing a long-term nidus for subsequent infection are the possible reason for persistent infection and root-end filling with MTA prevents the adhesion and penetration.

Elongational viscosity of photo-oxidated LDPE

Science.gov (United States)

Rolón-Garrido, Víctor H.; Wagner, Manfred H.

2014-05-01

Sheets of low-density polyethylene (LDPE) were photo-oxidatively treated at room temperature, and subsequently characterized rheologically in the melt state by shear and uniaxial extensional experiments. For photo-oxidation, a xenon lamp was used to irradiate the samples for times between 1 day and 6 weeks. Linear-viscoelastic characterization was performed in a temperature range of 130 to 220°C to obtain the master curve at 170°C, the reference temperature at which the elongational viscosities were measured. Linear viscoelasticity is increasingly affected by increasing photo-oxidation due to crosslinking of LDPE, as corroborated by an increasing gel fraction as determined by a solvent extraction method. The elongational measurements reveal a strong enhancement of strain hardening until a saturation level is achieved. The elongational data are analyzed in the frame work of two constitutive equations, the rubber-like liquid and the molecular stress function models. Within the experimental window, timedeformation separability is confirmed for all samples, independent of the degree of photo-oxidation.

POLYGALACTURONASE INVOLVED IN EXPANSION1 functions in cell elongation and flower development in Arabidopsis.

Science.gov (United States)

Xiao, Chaowen; Somerville, Chris; Anderson, Charles T

2014-03-01

Pectins are acidic carbohydrates that comprise a significant fraction of the primary walls of eudicotyledonous plant cells. They influence wall porosity and extensibility, thus controlling cell and organ growth during plant development. The regulated degradation of pectins is required for many cell separation events in plants, but the role of pectin degradation in cell expansion is poorly defined. Using an activation tag screen designed to isolate genes involved in wall expansion, we identified a gene encoding a putative polygalacturonase that, when overexpressed, resulted in enhanced hypocotyl elongation in etiolated Arabidopsis thaliana seedlings. We named this gene POLYGALACTURONASE INVOLVED IN EXPANSION1 (PGX1). Plants lacking PGX1 display reduced hypocotyl elongation that is complemented by transgenic PGX1 expression. PGX1 is expressed in expanding tissues throughout development, including seedlings, roots, leaves, and flowers. PGX1-GFP (green fluorescent protein) localizes to the apoplast, and heterologously expressed PGX1 displays in vitro polygalacturonase activity, supporting a function for this protein in apoplastic pectin degradation. Plants either overexpressing or lacking PGX1 display alterations in total polygalacturonase activity, pectin molecular mass, and wall composition and also display higher proportions of flowers with extra petals, suggesting PGX1's involvement in floral organ patterning. These results reveal new roles for polygalacturonases in plant development.

MreB-Dependent Inhibition of Cell Elongation during the Escape from Competence in Bacillus subtilis.

Directory of Open Access Journals (Sweden)

Nicolas Mirouze

2015-06-01

Full Text Available During bacterial exponential growth, the morphogenetic actin-like MreB proteins form membrane-associated assemblies that move processively following trajectories perpendicular to the long axis of the cell. Such MreB structures are thought to scaffold and restrict the movement of peptidoglycan synthesizing machineries, thereby coordinating sidewall elongation. In Bacillus subtilis, this function is performed by the redundant action of three MreB isoforms, namely MreB, Mbl and MreBH. mreB and mbl are highly transcribed from vegetative promoters. We have found that their expression is maximal at the end of exponential phase, and rapidly decreases to a low basal level upon entering stationary phase. However, in cells developing genetic competence, a stationary phase physiological adaptation, expression of mreB was specifically reactivated by the central competence regulator ComK. In competent cells, MreB was found in complex with several competence proteins by in vitro pull-down assays. In addition, it co-localized with the polar clusters formed by the late competence peripheral protein ComGA, in a ComGA-dependent manner. ComGA has been shown to be essential for the inhibition of cell elongation characteristic of cells escaping the competence state. We show here that the pathway controlling this elongation inhibition also involves MreB. Our findings suggest that ComGA sequesters MreB to prevent cell elongation and therefore the escape from competence.

The TOR Complex: An Emergency Switch for Root Behavior.

Science.gov (United States)

Yokawa, Ken; Baluška, František

2016-01-01

Target of rapamycin (TOR) kinase is known to be a controller of cell growth and aging, which determines the fine balance between growth rates and energy availabilities. It has been reported that many eukaryotes express TOR genes. In plants, TOR signaling modifies growth and development in response to a plant's energy status. An example of TOR action can be found in the root apices, which are active organs that explore the soil environment via vigorous growth and numerous tropisms. The exploratory nature of root apices requires a large energy supply for signaling, as well as for cell division and elongation. In the case of negative tropisms, roots must respond quickly to avoid patches of unfavorable soil conditions, again by consuming precious energy reserves. Here we review the current findings on TOR signaling in plants and animals, and propose possible roles for this important complex in driving plant root negative tropisms, particularly during light escape and salt avoidance behavior. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Bilateral elongated styloid process: Its anatomical, embryological and clinical implications

OpenAIRE

Bagoji Ishwar B, Hadimani Gavishiddappa A, Patil Balasaheb G, Bannur Balappa M,Ambadasu B

2013-01-01

The styloid process is a slender, elongated, cylindrical bony projection from temporal bone. It normally varies in length from 2 cm to 3 cm. During a routine demonstration of skull for MBBS students we found the bilateral elongated styloid process in dry human skull. The length of elongation measured on the right and left side was 6.0 & 5.9 cms respectively. Such abnormal elongation of the styloid process may cause compression on a number of vital vessels and nerves related to it, producing i...

Uniaxial Elongational viscosity of bidisperse polystyrene melts

DEFF Research Database (Denmark)

Nielsen, Jens Kromann; Rasmussen, Henrik K.; Hassager, Ole

2006-01-01

The startup and steady uniaxial elongational viscosity have been measured for three bidisperse polystyrene (PS) melts, consisting of blends of monodisperse PS with molecular weights of 52 kg/mole or 103 kg/mole and 390 kg/mole. The bidisperse melts have a maximum in the steady elongational...... viscosity, of up to a factor of 7 times the Trouton limit of 3 times the zero-shear viscosity....

Using dynamic input allocation for elongation control at FTU

International Nuclear Information System (INIS)

Boncagni, L.; Galeani, S.; Granucci, G.; Varano, G.; Vitale, V.; Zaccarian, L.

2010-01-01

In this paper we exploit the dynamic allocation scheme for input redundant control systems proposed in to achieve elongation control on FTU (Frascati Tokamak Upgrade). The scheme first serves as a means for regulating the current in the F coils. Then, due to the quasi-static relationship between the plasma elongation and the F coils current, elongation control is achieved by suitably generalizing the allocation scheme. Both simulation and experimental results are reported.

Mitogen activated protein kinase 6 and MAP kinase phosphatase 1 are involved in the response of Arabidopsis roots to L-glutamate.

Science.gov (United States)

López-Bucio, Jesús Salvador; Raya-González, Javier; Ravelo-Ortega, Gustavo; Ruiz-Herrera, León Francisco; Ramos-Vega, Maricela; León, Patricia; López-Bucio, José; Guevara-García, Ángel Arturo

2018-03-01

The function and components of L-glutamate signaling pathways in plants have just begun to be elucidated. Here, using a combination of genetic and biochemical strategies, we demonstrated that a MAPK module is involved in the control of root developmental responses to this amino acid. Root system architecture plays an essential role in plant adaptation to biotic and abiotic factors via adjusting signal transduction and gene expression. L-Glutamate (L-Glu), an amino acid with neurotransmitter functions in animals, inhibits root growth, but the underlying genetic mechanisms are poorly understood. Through a combination of genetic analysis, in-gel kinase assays, detailed cell elongation and division measurements and confocal analysis of expression of auxin, quiescent center and stem cell niche related genes, the critical roles of L-Glu in primary root growth acting through the mitogen-activated protein kinase 6 (MPK6) and the dual specificity serine-threonine-tyrosine phosphatase MKP1 could be revealed. In-gel phosphorylation assays revealed a rapid and dose-dependent induction of MPK6 and MPK3 activities in wild-type Arabidopsis seedlings in response to L-Glu. Mutations in MPK6 or MKP1 reduced or increased root cell division and elongation in response to L-Glu, possibly modulating auxin transport and/or response, but in a PLETHORA1 and 2 independent manner. Our data highlight MPK6 and MKP1 as components of an L-Glu pathway linking the auxin response, and cell division for primary root growth.

Optimizing the chemical aspect of root canal irrigation

NARCIS (Netherlands)

de Macedo, R.G.

2013-01-01

Root canal treatment is aimed at the removal of inflamed and infected tissue present in the root canal system. It will prevent the entrance of new microorganisms or nutrients in order to maintain or create a healthy environment around the root. There is sufficient evidence that shows that

Innate immune responses activated in Arabidopsis roots by microbe-associated molecular patterns.

Science.gov (United States)

Millet, Yves A; Danna, Cristian H; Clay, Nicole K; Songnuan, Wisuwat; Simon, Matthew D; Werck-Reichhart, Danièle; Ausubel, Frederick M

2010-03-01

Despite the fact that roots are the organs most subject to microbial interactions, very little is known about the response of roots to microbe-associated molecular patterns (MAMPs). By monitoring transcriptional activation of beta-glucuronidase reporters and MAMP-elicited callose deposition, we show that three MAMPs, the flagellar peptide Flg22, peptidoglycan, and chitin, trigger a strong tissue-specific response in Arabidopsis thaliana roots, either at the elongation zone for Flg22 and peptidoglycan or in the mature parts of the roots for chitin. Ethylene signaling, the 4-methoxy-indole-3-ylmethylglucosinolate biosynthetic pathway, and the PEN2 myrosinase, but not salicylic acid or jasmonic acid signaling, play major roles in this MAMP response. We also show that Flg22 induces the cytochrome P450 CYP71A12-dependent exudation of the phytoalexin camalexin by Arabidopsis roots. The phytotoxin coronatine, an Ile-jasmonic acid mimic produced by Pseudomonas syringae pathovars, suppresses MAMP-activated responses in the roots. This suppression requires the E3 ubiquitin ligase COI1 as well as the transcription factor JIN1/MYC2 but does not rely on salicylic acid-jasmonic acid antagonism. These experiments demonstrate the presence of highly orchestrated and tissue-specific MAMP responses in roots and potential pathogen-encoded mechanisms to block these MAMP-elicited signaling pathways.

Measurement and analysis of pressure tube elongation in the Douglas Point reactor

International Nuclear Information System (INIS)

Causey, A.R.; MacEwan, S.R.; Jamieson, H.C.; Mitchell, A.B.

1980-02-01

Elongations of zirconium alloy pressure tubes in CANDU reactors, which occur as a result of neutron-irradiation-induced creep and growth, have been measured over the past 6 years, and the consequences of thses elongations have recently been analysed. Elongation rates, previously deduced from extensive measurements of elongations of cold-worked Zircaloy-2 pressure tubes in the Pickering reactors, have been modified to apply to the pressure tubes in the Douglas Point (DP) reactor by taking into account measured diffences in texture and dislocation density. Using these elongation rates, and structural data unique to the DP reactor, the analysis predicts elongation behaviour which is in good agreement with pressure tube elongations measured during the ten years of reactor operation. (Auth)

Root isolations of Metarhizium spp. from crops reflect diversity in the soil and indicate no plant specificity

DEFF Research Database (Denmark)

Steinwender, Bernhardt M.; Enkerli, Jürg; Widmer, Franco

2015-01-01

elongation factor 1-alpha and characterized by simple sequence repeat (SSR) analysis of 14 different loci. Metarhizium brunneum was the most common species isolated from plant roots (84.1% of all isolates), while M. robertsii (11.1%) and M. majus (4.8%) comprised the remainder. The SSR analysis revealed...

The influence of surface and incorporated lime and gypsiferous by-products on surface and subsurface soil acidity. II. Root growth and agronomic implications

Energy Technology Data Exchange (ETDEWEB)

Wang, H.L.; Hedley, M.J.; Bolan, N.S.; Horne, D.J. [New Zealand Forest Research Institute, Rotorua (New Zealand)

1999-04-01

Lucerne (Medicago sativa. L) root elongation in acid soils amended by gypsiferous coal combustion by-products was investigated in a glasshouse study. Lime, fluidised bed boiler ash (FBA), and flue gas desulfurisation gypsum (FGDG) were mixed into the surface 50 mm of either an Allophanic (the Patua sand loam) or an Ultic (the Kaawa clay loam) soil column, at rates containing calcium equivalent to 5000 kg/ha of CaCO{sub 3}. Lucerne was grown on each column after it was leached with 400 mm of water. Whereas the lime treatment had no effect on root elongation in the acidic subsurface of the Patua soil, the FBA and FGDG treatments significantly improved lucerne root penetration into the subsurface soil. This was due to the `self liming effect` induced by sulfate adsorption. In contrast, topsoil incorporated amendments did not influence root penetration into the acidic subsurface of the Kaawa soil, which is dominated by permanently charged clay minerals. The `self-liming erect` caused by gypsum application is not a sustainable practice. Lime should be applied to neutralise the topsoil acidity, when gypsum is used as subsurface soil acidity ameliorant. FBA, which contains both lime and gypsum, can meet these requirements.

Dual inhibition of mTORC1 and mTORC2 perturbs cytoskeletal organization and impairs endothelial cell elongation.

Science.gov (United States)

Tsuji-Tamura, Kiyomi; Ogawa, Minetaro

2018-02-26

Elongation of endothelial cells is an important process in vascular formation and is expected to be a therapeutic target for inhibiting tumor angiogenesis. We have previously demonstrated that inhibition of mTORC1 and mTORC2 impaired endothelial cell elongation, although the mechanism has not been well defined. In this study, we analyzed the effects of the mTORC1-specific inhibitor everolimus and the mTORC1/mTORC2 dual inhibitor KU0063794 on the cytoskeletal organization and morphology of endothelial cell lines. While both inhibitors equally inhibited cell proliferation, KU0063794 specifically caused abnormal accumulation of F-actin and disordered distribution of microtubules, thereby markedly impairing endothelial cell elongation and tube formation. The effects of KU0063794 were phenocopied by paclitaxel treatment, suggesting that KU0063794 might impair endothelial cell morphology through over-stabilization of microtubules. Although mTORC1 is a key signaling molecule in cell proliferation and has been considered a target for preventing angiogenesis, mTORC1 inhibitors have not been sufficient to suppress angiogenesis. Our results suggest that mTORC1/mTORC2 dual inhibition is more effective for anti-angiogenic therapy, as it impairs not only endothelial cell proliferation, but also endothelial cell elongation. Copyright © 2018 Elsevier Inc. All rights reserved.

Nuclear starburst activity induced by elongated bulges in spiral galaxies

Science.gov (United States)

Kim, Eunbin; Kim, Sungsoo S.; Choi, Yun-Young; Lee, Gwang-Ho; de Grijs, Richard; Lee, Myung Gyoon; Hwang, Ho Seong

2018-06-01

We study the effects of bulge elongation on the star formation activity in the centres of spiral galaxies using the data from the Sloan Digital Sky Survey Data Release 7. We construct a volume-limited sample of face-on spiral galaxies with Mr nuclear starbursts using the fibre specific star formation rates derived from the SDSS spectra. We find a statistically significant correlation between bulge elongation and nuclear starbursts in the sense that the fraction of nuclear starbursts increases with bulge elongation. This correlation is more prominent for fainter and redder galaxies, which exhibit higher ratios of elongated bulges. We find no significant environmental dependence of the correlation between bulge elongation and nuclear starbursts. These results suggest that non-axisymmetric bulges can efficiently feed the gas into the centre of galaxies to trigger nuclear starburst activity.

The plasma membrane H⁺ -ATPase AHA2 contributes to the root architecture in response to different nitrogen supply

DEFF Research Database (Denmark)

Młodzińska, Ewa; Kłobus, Grażyna; Christensen, Monica Daugbjerg

2015-01-01

of lateral root primordia, root elongation and increase the root biomass. However, the signal transduction mechanisms, which enable roots to sense changes in different mineral environments and match their growth and development patterns to actual conditions in the soil, are still unknown. Most recent...... comments have focused on one of the essential macroelements, namely nitrogen, and its role in the modification of the root architecture of Arabidopsis thaliana. As yet, not all elements of the signal transduction pathway leading to the perception of the nitrate stimulus, and hence to anatomical changes...... of the root, which allow for adaptation to variable ion concentrations in the soil, are known. Our data demonstrate that primary and lateral root length were shorter lower in aha2 mutant lines compared to wild-type plants in response to a variable nitrogen source. This suggests that the plasma membrane proton...

Increased root hair density by loss of WRKY6 in Arabidopsis thaliana

Directory of Open Access Journals (Sweden)

Markus G. Stetter

2017-01-01

Full Text Available Root hairs are unicellular elongations of certain rhizodermal cells that improve the uptake of sparingly soluble and immobile soil nutrients. Among different Arabidopsis thaliana genotypes, root hair density, length and the local acclimation to low inorganic phosphate (Pi differs considerably, when analyzed on split agar plates. Here, genome-wide association fine mapping identified significant single nucleotide polymorphisms associated with the increased root hair density in the absence of local phosphate on chromosome 1. A loss-of-functionmutant of the candidate transcription factor gene WRKY6, which is involved in the acclimation of plants to low phosphorus, had increased root hair density. This is partially explained by a reduced cortical cell diameter in wrky6-3, reducing the rhizodermal cell numbers adjacent to the cortical cells. As a consequence, rhizodermal cells in positions that are in contact with two cortical cells are found more often, leading to higher hair density. Distinct cortical cell diameters and epidermal cell lengths distinguish other Arabidopsis accessions with distinct root hair density and −Pi response from diploid Col-0, while tetraploid Col-0 had generally larger root cell sizes, which explain longer hairs. A distinct radial root morphology within Arabidopsis accessions and wrky6-3explains some, but not all, differences in the root hair acclimation to –Pi.

Scatter factor corrections for elongated fields

International Nuclear Information System (INIS)

Higgins, P.D.; Sohn, W.H.; Sibata, C.H.; McCarthy, W.A.

1989-01-01

Measurements have been made to determine scatter factor corrections for elongated fields of Cobalt-60 and for nominal linear accelerator energies of 6 MV (Siemens Mevatron 67) and 18 MV (AECL Therac 20). It was found that for every energy the collimator scatter factor varies by 2% or more as the field length-to-width ratio increases beyond 3:1. The phantom scatter factor is independent of which collimator pair is elongated at these energies. For 18 MV photons it was found that the collimator scatter factor is complicated by field-size-dependent backscatter into the beam monitor

Novel technique for repairing posterior medial meniscus root tears using porcine knees and biomechanical study.

Directory of Open Access Journals (Sweden)

Jia-Lin Wu

Full Text Available Transtibial pullout suture (TPS repair of posterior medial meniscus root (PMMR tears was shown to achieve good clinical outcomes. The purpose of this study was to compare biomechanically, a novel technique designed to repair PMMR tears using tendon graft (TG and conventional TPS repair. Twelve porcine tibiae (n = 6 each TG group: flexor digitorum profundus tendon was passed through an incision in the root area, created 5 mm postero-medially along the edge of the attachment area. TPS group: a modified Mason-Allen suture was created using no. 2 FiberWire. The tendon grafts and sutures were threaded through the bone tunnel and then fixed to the anterolateral cortex of the tibia. The two groups underwent cyclic loading followed by a load-to-failure test. Displacements of the constructs after 100, 500, and 1000 loading cycles, and the maximum load, stiffness, and elongation at failure were recorded. The TG technique had significantly lower elongation and higher stiffness compared with the TPS. The maximum load of the TG group was significantly lower than that of the TPS group. Failure modes for all specimens were caused by the suture or graft cutting through the meniscus. Lesser elongation and higher stiffness of the constructs in TG technique over those in the standard TPS technique might be beneficial for postoperative biological healing between the meniscus and tibial plateau. However, a slower rehabilitation program might be necessary due to its relatively lower maximum failure load.

FtsZ-Dependent Elongation of a Coccoid Bacterium

Directory of Open Access Journals (Sweden)

Ana R. Pereira

2016-09-01

Full Text Available A mechanistic understanding of the determination and maintenance of the simplest bacterial cell shape, a sphere, remains elusive compared with that of more complex shapes. Cocci seem to lack a dedicated elongation machinery, and a spherical shape has been considered an evolutionary dead-end morphology, as a transition from a spherical to a rod-like shape has never been observed in bacteria. Here we show that a Staphylococcus aureus mutant (M5 expressing the ftsZG193D allele exhibits elongated cells. Molecular dynamics simulations and in vitro studies indicate that FtsZG193D filaments are more twisted and shorter than wild-type filaments. In vivo, M5 cell wall deposition is initiated asymmetrically, only on one side of the cell, and progresses into a helical pattern rather than into a constricting ring as in wild-type cells. This helical pattern of wall insertion leads to elongation, as in rod-shaped cells. Thus, structural flexibility of FtsZ filaments can result in an FtsZ-dependent mechanism for generating elongated cells from cocci.

Enhanced gravitropism of roots with a disrupted cap actin cytoskeleton

Science.gov (United States)

Hou, Guichuan; Mohamalawari, Deepti R.; Blancaflor, Elison B.

2003-01-01

The actin cytoskeleton has been proposed to be a major player in plant gravitropism. However, understanding the role of actin in this process is far from complete. To address this problem, we conducted an analysis of the effect of Latrunculin B (Lat B), a potent actin-disrupting drug, on root gravitropism using various parameters that included detailed curvature kinetics, estimation of gravitropic sensitivity, and monitoring of curvature development after extended clinorotation. Lat B treatment resulted in a promotion of root curvature after a 90 degrees reorientation in three plant species tested. More significantly, the sensitivity of maize (Zea mays) roots to gravity was enhanced after actin disruption, as determined from a comparison of presentation time of Lat B-treated versus untreated roots. A short 10-min gravistimulus followed by extended rotation on a 1-rpm clinostat resulted in extensive gravitropic responses, manifested as curvature that often exceeded 90 degrees. Application of Lat B to the cap or elongation zone of maize roots resulted in the disruption of the actin cytoskeleton, which was confined to the area of localized Lat B application. Only roots with Lat B applied to the cap displayed the strong curvature responses after extended clinorotation. Our study demonstrates that disrupting the actin cytoskeleton in the cap leads to the persistence of a signal established by a previous gravistimulus. Therefore, actin could function in root gravitropism by providing a mechanism to regulate the proliferation of a gravitropic signal originating from the cap to allow the root to attain its correct orientation or set point angle.

Influence of Gradual Elongation to the Patella Tendon Insertion in Rabbits

Directory of Open Access Journals (Sweden)

Hirotaka Mutsuzaki

2014-08-01

Full Text Available The purpose of this study was to examine the histological changes at the patella tendon (PT insertion site under gradual elongation in rabbits. Gradual elongation of the PT was performed using external fixation for 4 weeks, with a lengthening speed of 0.5 mm/day (elongation group; n = 24. Rabbits in the sham group underwent the same surgical procedure without gradual elongation (sham group; n = 24. Eight animals were sacrificed 1, 2 and 4 weeks after surgery in each group, respectively. Average thicknesses of stained glycosaminoglycan (GAGs areas by Safranin-O staining in the total cartilage layer and the uncalcified fibrocartilage layer in the elongation group were significantly higher than that in the sham group at 4 weeks (p < 0.05 and that in the intact PT group (n = 6, p < 0.05. In the elongation group, the peak in the average thicknesses of the stained GAGs areas in the total cartilage layer and the uncalcified fibrocartilage layer were observed at 4 weeks. Gradual elongation of PT insertion significantly affected the increase in the average thicknesses of the stained GAGs areas in the cartilage layer especially in the uncalcified fibrocartilage layer at 4 weeks in rabbits. Clinically, insertions of tendon and ligament can extend during gradual elongation using external fixation more than 4 weeks after the operation.

Tree-shoot elongation patterns in a gamma-irradiated northern forest community

International Nuclear Information System (INIS)

Buech, R.R.; Salmonson, B.J.

1977-01-01

Shoot elongation in the upper crowns of seven tree species was studied in a gamma-irradiated northern forest community near Rhinelander, Wis. Observations on the pattern and duration of shoot elongation are presented for the irradiation (1972) and postirradiation (1973) growing seasons. The gymnosperm Abies balsamea was the most radiosensitive species. Significant alteration in pattern and duration was observed in 1973 at exposure rates of 4 to 25 r/20-hr day; 31 r/20-hr day was lethal. At the other extreme, 116 r/20-hr day produced no significant effects on Acer saccharum shoot elongation pattern or duration. Acer rubrum, Betula papyrifera, Populus tremuloides, Quercus rubra, and Tilia americana were intermediate in radiosensitivity. Observed responses to radiation were alteration in the elongation pattern, suppression of internodal elongation, and death. Effects of the 1972 growing-season exposure were most obvious in the subsequent growing seasons. Retardation of initial elongation was characteristic of all species. Cessation of elongation was variable, even within species (e.g., P. tremuloides). The results suggest that bud differentiation and morphology and dependency on food reserves contributed to the lag in manifestation of radiation damage. The resultant crown characteristics are described and explained

Halotolerant PGPRs Prevent Major Shifts in Indigenous Microbial Community Structure Under Salinity Stress.

Science.gov (United States)

Bharti, Nidhi; Barnawal, Deepti; Maji, Deepamala; Kalra, Alok

2015-07-01

The resilience of soil microbial populations and processes to environmental perturbation is of increasing interest as alteration in rhizosphere microbial community dynamics impacts the combined functions of plant-microbe interactions. The present study was conducted to investigate the effect of inoculation with halotolerant rhizobacteria Bacillus pumilus (STR2), Halomonas desiderata (STR8), and Exiguobacterium oxidotolerans (STR36) on the indigenous root-associated microbial (bacterial and fungal) communities in maize under non-saline and salinity stress. Plants inoculated with halotolerant rhizobacteria recorded improved growth as illustrated by significantly higher shoot and root dry weight and elongation in comparison to un-inoculated control plants under both non-saline and saline conditions. Additive main effect and multiplicative interaction ordination analysis revealed that plant growth promoting rhizobacteria (PGPR) inoculations as well as salinity are major drivers of microbial community shift in maize rhizosphere. Salinity negatively impacts microbial community as analysed through diversity indices; among the PGPR-inoculated plants, STR2-inoculated plants recorded higher values of diversity indices. As observed in the terminal-restriction fragment length polymorphism analysis, the inoculation of halotolerant rhizobacteria prevents major shift of the microbial community structure, thus enhancing the resilience capacity of the microbial communities.

Mutual interdependence of splicing and transcription elongation.

Science.gov (United States)

Brzyżek, Grzegorz; Świeżewski, Szymon

2015-01-01

Transcription and splicing are intrinsically linked, as splicing needs a pre-mRNA substrate to commence. The more nuanced view is that the rate of transcription contributes to splicing regulation. On the other hand there is accumulating evidence that splicing has an active role in controlling transcription elongation by DNA-dependent RNA polymerase II (RNAP II). We briefly review those mechanisms and propose a unifying model where splicing controls transcription elongation to provide an optimal timing for successive rounds of splicing.

Optimizing the chemical aspect of root canal irrigation

OpenAIRE

de Macedo, R.G.

2013-01-01

Root canal treatment is aimed at the removal of inflamed and infected tissue present in the root canal system. It will prevent the entrance of new microorganisms or nutrients in order to maintain or create a healthy environment around the root. There is sufficient evidence that shows that traditional endodontic therapy cannot make the root canal system completely free of bacteria. Moreover, it may not always result in complete healing of apical periodontitis, highlighting the need of optimizi...

Evolution and Allometry of Calcaneal Elongation in Living and Extinct Primates

Science.gov (United States)

Boyer, Doug M.; Seiffert, Erik R.; Gladman, Justin T.; Bloch, Jonathan I.

2013-01-01

Specialized acrobatic leaping has been recognized as a key adaptive trait tied to the origin and subsequent radiation of euprimates based on its observed frequency in extant primates and inferred frequency in extinct early euprimates. Hypothesized skeletal correlates include elongated tarsal elements, which would be expected to aid leaping by allowing for increased rates and durations of propulsive acceleration at takeoff. Alternatively, authors of a recent study argued that pronounced distal calcaneal elongation of euprimates (compared to other mammalian taxa) was related primarily to specialized pedal grasping. Testing for correlations between calcaneal elongation and leaping versus grasping is complicated by body size differences and associated allometric affects. We re-assess allometric constraints on, and the functional significance of, calcaneal elongation using phylogenetic comparative methods, and present an evolutionary hypothesis for the evolution of calcaneal elongation in primates using a Bayesian approach to ancestral state reconstruction (ASR). Results show that among all primates, logged ratios of distal calcaneal length to total calcaneal length are inversely correlated with logged body mass proxies derived from the area of the calcaneal facet for the cuboid. Results from phylogenetic ANOVA on residuals from this allometric line suggest that deviations are explained by degree of leaping specialization in prosimians, but not anthropoids. Results from ASR suggest that non-allometric increases in calcaneal elongation began in the primate stem lineage and continued independently in haplorhines and strepsirrhines. Anthropoid and lorisid lineages show stasis and decreasing elongation, respectively. Initial increases in calcaneal elongation in primate evolution may be related to either development of hallucal-grasping or a combination of grasping and more specialized leaping behaviors. As has been previously suggested, subsequent increases in calcaneal

QTL analysis of internode elongation in response to gibberellin in deepwater rice

OpenAIRE

Nagai, Keisuke; Kondo, Yuma; Kitaoka, Takuya; Noda, Tomonori; Kuroha, Takeshi; Angeles-Shim, Rosalyn B.; Yasui, Hideshi; Yoshimura, Atsushi; Ashikari, Motoyuki

2014-01-01

Gibberellin (GA) is a plant hormone that has important roles in numerous plant developmental phases. Rice plants known as deepwater rice respond to flooding by elongating their internodes to avoid anoxia. Previous studies reported that GA is essential for internode elongation in deepwater rice. Quantitative trait locus (QTL) analyses identified QTLs regulating internode elongation in response to deepwater conditions. However, the interaction between internode elongation and regulators of GA s...

The Caenorhabditis elegans Elongator complex regulates neuronal alpha-tubulin acetylation.

Directory of Open Access Journals (Sweden)

Jachen A Solinger

2010-01-01

Full Text Available Although acetylated alpha-tubulin is known to be a marker of stable microtubules in neurons, precise factors that regulate alpha-tubulin acetylation are, to date, largely unknown. Therefore, a genetic screen was employed in the nematode Caenorhabditis elegans that identified the Elongator complex as a possible regulator of alpha-tubulin acetylation. Detailed characterization of mutant animals revealed that the acetyltransferase activity of the Elongator is indeed required for correct acetylation of microtubules and for neuronal development. Moreover, the velocity of vesicles on microtubules was affected by mutations in Elongator. Elongator mutants also displayed defects in neurotransmitter levels. Furthermore, acetylation of alpha-tubulin was shown to act as a novel signal for the fine-tuning of microtubules dynamics by modulating alpha-tubulin turnover, which in turn affected neuronal shape. Given that mutations in the acetyltransferase subunit of the Elongator (Elp3 and in a scaffold subunit (Elp1 have previously been linked to human neurodegenerative diseases, namely Amyotrophic Lateral Sclerosis and Familial Dysautonomia respectively highlights the importance of this work and offers new insights to understand their etiology.

Phytotoxicity of ZnO nanoparticles and the released Zn(II) ion to corn (Zea mays L.) and cucumber (Cucumis sativus L.) during germination.

Science.gov (United States)

Zhang, Ruichang; Zhang, Haibo; Tu, Chen; Hu, Xuefeng; Li, Lianzhen; Luo, Yongming; Christie, Peter

2015-07-01

Toxicity of engineered nanoparticles on organisms is of concern worldwide due to their extensive use and unique properties. The impacts of ZnO nanoparticles (ZnO NPs) on seed germination and root elongation of corn (Zea mays L.) and cucumber (Cucumis sativus L.) were investigated in this study. The role of seed coats of corn in the mitigation toxicity of nanoparticles was also evaluated. ZnO NPs (1,000 mg L(-1)) reduced root length of corn and cucumber by 17 % (p < 0.05) and 51 % (p < 0.05), respectively, but exhibited no effects on germination. In comparison with Zn(2+), toxicity of ZnO NPs on the root elongation of corn could be attributed to the nanoparticulate ZnO, while released Zn ion from ZnO could solely contribute to the inhibition of root elongation of cucumber. Zn uptake in corn exposed to ZnO NPs during germination was much higher than that in corn exposed to Zn(2+), whereas Zn uptake in cucumber was significantly correlated with soluble Zn in suspension. It could be inferred that Zn was taken up by corn and cucumber mainly in the form of ZnO NPs and soluble Zn, respectively. Transmission electron microscope confirmed the uptake of ZnO NPs into root of corn. Although isolation of the seed coats might not be the principal factor that achieved avoidance from toxicity on germination, seed coats of corn were found to mitigate the toxicity of ZnO NPs on root elongation and prevent approximately half of the Zn from entering into root and endosperm.

Inhibition of ethylene production by putrescine alleviates aluminium-induced root inhibition in wheat plants.

Science.gov (United States)

Yu, Yan; Jin, Chongwei; Sun, Chengliang; Wang, Jinghong; Ye, Yiquan; Zhou, Weiwei; Lu, Lingli; Lin, Xianyong

2016-01-08

Inhibition of root elongation is one of the most distinct symptoms of aluminium (Al) toxicity. Although putrescine (Put) has been identified as an important signaling molecule involved in Al tolerance, it is yet unknown how Put mitigates Al-induced root inhibition. Here, the possible mechanism was investigated by using two wheat genotypes differing in Al resistance: Al-tolerant Xi Aimai-1 and Al-sensitive Yangmai-5. Aluminium caused more root inhibition in Yangmai-5 and increased ethylene production at the root apices compared to Xi Aimai-1, whereas the effects were significantly reversed by ethylene biosynthesis inhibitors. The simultaneous exposure of wheat seedlings to Al and ethylene donor, ethephon, or ethylene biosynthesis precursor, 1-aminocyclopropane-1-carboxylic acid (ACC), increased ethylene production and aggravated root inhibition, which was more pronounced in Xi Aimai-1. In contrast, Put treatment decreased ethylene production and alleviated Al-induced root inhibition in both genotypes, and the effects were more conspicuous in Yangmai-5. Furthermore, our results indicated that Al-induced ethylene production was mediated by ACC synthase (ACS) and ACC oxidase, and that Put decreased ethylene production by inhibiting ACS. Altogether, these findings indicate that ethylene is involved in Al-induced root inhibition and this process could be alleviated by Put through inhibiting ACS activity.

A pea chloroplast translation elongation factor that is regulated by abiotic factors

International Nuclear Information System (INIS)

Singh, B.N.; Mishra, R.N.; Agarwal, Pradeep K.; Goswami, Mamta; Nair, Suresh; Sopory, S.K.; Reddy, M.K.

2004-01-01

We report the cloning and characterization of both the cDNA (tufA) and genomic clones encoding for a chloroplast translation elongation factor (EF-Tu) from pea. The analysis of the deduced amino acids of the cDNA clone reveals the presence of putative transit peptide sequence and four GTP binding domains and two EF-Tu signature motifs in the mature polypeptide region. Using in vivo immunostaining followed by confocal microscopy pea EF-Tu was localized to chloroplast. The steady state transcript level of pea tufA was high in leaves and not detectable in roots. The expression of this gene is stimulated by light. The differential expression of this gene in response to various abiotic stresses showed that it is down-regulated in response to salinity and ABA and up-regulated in response to low temperature and salicylic acid treatment. These results indicate that regulation of pea tufA may have an important role in plant adaptation to environmental stresses

The social justice roots of the Mentors in Violence Prevention model and its application in a high school setting.

Science.gov (United States)

Katz, Jackson; Heisterkamp, H Alan; Fleming, Wm Michael

2011-06-01

The social justice roots and theory of the Mentors in Violence Prevention (MVP) model is presented, followed by an empirical study examining the influence of MVP in high school settings. Findings reveal students exposed to the MVP model are more likely to see forms of violence as being wrong and are more likely to take actions to intervene than students not exposed to the program. Findings support the premises on which MVP is founded.

Adenylate cyclase regulates elongation of mammalian primary cilia

International Nuclear Information System (INIS)

Ou, Young; Ruan, Yibing; Cheng, Min; Moser, Joanna J.; Rattner, Jerome B.; Hoorn, Frans A. van der

2009-01-01

The primary cilium is a non-motile microtubule-based structure that shares many similarities with the structures of flagella and motile cilia. It is well known that the length of flagella is under stringent control, but it is not known whether this is true for primary cilia. In this study, we found that the length of primary cilia in fibroblast-like synoviocytes, either in log phase culture or in quiescent state, was confined within a range. However, when lithium was added to the culture to a final concentration of 100 mM, primary cilia of synoviocytes grew beyond this range, elongating to a length that was on average approximately 3 times the length of untreated cilia. Lithium is a drug approved for treating bipolar disorder. We dissected the molecular targets of this drug, and observed that inhibition of adenylate cyclase III (ACIII) by specific inhibitors mimicked the effects of lithium on primary cilium elongation. Inhibition of GSK-3β by four different inhibitors did not induce primary cilia elongation. ACIII was found in primary cilia of a variety of cell types, and lithium treatment of these cell types led to their cilium elongation. Further, we demonstrate that different cell types displayed distinct sensitivities to the lithium treatment. However, in all cases examined primary cilia elongated as a result of lithium treatment. In particular, two neuronal cell types, rat PC-12 adrenal medulla cells and human astrocytes, developed long primary cilia when lithium was used at or close to the therapeutic relevant concentration (1-2 mM). These results suggest that the length of primary cilia is controlled, at least in part, by the ACIII-cAMP signaling pathway.

Adenylate cyclase regulates elongation of mammalian primary cilia

Energy Technology Data Exchange (ETDEWEB)

Ou, Young; Ruan, Yibing; Cheng, Min; Moser, Joanna J. [Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, T2N 4N1 (Canada); Rattner, Jerome B. [Department of Cell Biology and Anatomy, Faculty of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, T2N 4N1 (Canada); Hoorn, Frans A. van der, E-mail: fvdhoorn@ucalgary.ca [Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, T2N 4N1 (Canada)

2009-10-01

The primary cilium is a non-motile microtubule-based structure that shares many similarities with the structures of flagella and motile cilia. It is well known that the length of flagella is under stringent control, but it is not known whether this is true for primary cilia. In this study, we found that the length of primary cilia in fibroblast-like synoviocytes, either in log phase culture or in quiescent state, was confined within a range. However, when lithium was added to the culture to a final concentration of 100 mM, primary cilia of synoviocytes grew beyond this range, elongating to a length that was on average approximately 3 times the length of untreated cilia. Lithium is a drug approved for treating bipolar disorder. We dissected the molecular targets of this drug, and observed that inhibition of adenylate cyclase III (ACIII) by specific inhibitors mimicked the effects of lithium on primary cilium elongation. Inhibition of GSK-3{beta} by four different inhibitors did not induce primary cilia elongation. ACIII was found in primary cilia of a variety of cell types, and lithium treatment of these cell types led to their cilium elongation. Further, we demonstrate that different cell types displayed distinct sensitivities to the lithium treatment. However, in all cases examined primary cilia elongated as a result of lithium treatment. In particular, two neuronal cell types, rat PC-12 adrenal medulla cells and human astrocytes, developed long primary cilia when lithium was used at or close to the therapeutic relevant concentration (1-2 mM). These results suggest that the length of primary cilia is controlled, at least in part, by the ACIII-cAMP signaling pathway.

Study on preventive and therapeutic function of compound white peony root oral liquids in treating radiation-induced esophagitis

International Nuclear Information System (INIS)

Shen Li; Shan Baoen; Zhang Li; Li Wei; Gong Yanjun; Gao Haixiang

2007-01-01

Wistar rats were divided into seven groups: the normal group, the irradiated group, the preventive group treated with the normal dose of compound white peony root oral liquids (cWPROL) (immediately administered on the day after rats were irradiated), the preventive group treated with the high dose of cWPROL (immediately administered on the day after rats were irradiated), the group treated with normal dose of cWPROL (administered on the 7th day after rats were irradiated), the group treated with high dose of cWPROL (administered on the 7th day after rats were irradiated), the group treated with Western medicine administered from the seventh day after irradiation. The radiation esophagitis of rats was induced by single irradiation of 43 Gy gamma ray locally. Then the rats with radiation esophagitis were treated in different ways. The food weight, water volume intaked by the rats and its body weight change were observed; The rats were killed on the 14th day after irradiation and the leucocyte count and DIFF were analyzed and the esophageal pathological sections were made. The pathological change of rats' esophageal mucosa and ultrastructure change of cells were observed for different groups. The results showed all the cWPROL and Western medicine have therapeutic function of treating radiation-induced esophagitis of rats. The ultrastructure of cells of rats in the group treated with normal dose of cWPROL recovered. The food weight and water volume intaked by the rats had increased in the group infused with cWPROL compared with purely irradiated groups, especially in the preventive group treated with high dose of cWPROL. The weight of food, the WBC count, the lymphocyte differential count in the group which was treated with Western medicine decreased compared with the purely irradiated group. Lymphocyte differential count increased in the groups administered cWPROL compared with the purely irradiated group. The compound white peony root oral liquids serves the function

Rooting phylogenies using gene duplications: an empirical example from the bees (Apoidea).

Science.gov (United States)

Brady, Seán G; Litman, Jessica R; Danforth, Bryan N

2011-09-01

The placement of the root node in a phylogeny is fundamental to characterizing evolutionary relationships. The root node of bee phylogeny remains unclear despite considerable previous attention. In order to test alternative hypotheses for the location of the root node in bees, we used the F1 and F2 paralogs of elongation factor 1-alpha (EF-1α) to compare the tree topologies that result when using outgroup versus paralogous rooting. Fifty-two taxa representing each of the seven bee families were sequenced for both copies of EF-1α. Two datasets were analyzed. In the first (the "concatenated" dataset), the F1 and F2 copies for each species were concatenated and the tree was rooted using appropriate outgroups (sphecid and crabronid wasps). In the second dataset (the "duplicated" dataset), the F1 and F2 copies were aligned to each another and each copy for all taxa were treated as separate terminals. In this dataset, the root was placed between the F1 and F2 copies (e.g., paralog rooting). Bayesian analyses demonstrate that the outgroup rooting approach outperforms paralog rooting, recovering deeper clades and showing stronger support for groups well established by both morphological and other molecular data. Sequence characteristics of the two copies were compared at the amino acid level, but little evidence was found to suggest that one copy is more functionally conserved. Although neither approach yields an unambiguous root to the tree, both approaches strongly indicate that the root of bee phylogeny does not fall near Colletidae, as has been previously proposed. We discuss paralog rooting as a general strategy and why this approach performs relatively poorly with our particular dataset. Copyright © 2011 Elsevier Inc. All rights reserved.

Characteristics of a root hair-less line of Arabidopsis thaliana under physiological stresses.

Science.gov (United States)

Tanaka, Natsuki; Kato, Mariko; Tomioka, Rie; Kurata, Rie; Fukao, Yoichiro; Aoyama, Takashi; Maeshima, Masayoshi

2014-04-01

The plasma membrane-associated Ca(2+)-binding protein-2 of Arabidopsis thaliana is involved in the growth of root hair tips. Several transgenic lines that overexpress the 23 residue N-terminal domain of this protein under the control of the root hair-specific EXPANSIN A7 promoter lack root hairs completely. The role of root hairs under normal and stress conditions was examined in one of these root hair-less lines (NR23). Compared with the wild type, NR23 showed a 47% reduction in water absorption, decreased drought tolerance, and a lower ability to adapt to heat. Growth of NR23 was suppressed in media deficient in phosphorus, iron, calcium, zinc, copper, or potassium. Also, the content of an individual mineral in NR23 grown in normal medium, or in medium lacking a specific mineral, was relatively low. In wild-type plants, the primary and lateral roots produce numerous root hairs that become elongated under phosphate-deficient conditions; NR23 did not produce root hairs. Although several isoforms of the plasma membrane phosphate transporters including PHT1;1-PHT1;6 were markedly induced after growth in phosphate-deficient medium, the levels induced in NR23 were less than half those observed in the wild type. In phosphate-deficient medium, the amounts of acid phosphatase, malate, and citrate secreted from NR23 roots were 38, 9, and 16% of the levels secreted from wild-type roots. The present results suggest that root hairs play significant roles in the absorption of water and several minerals, secretion of acid phosphatase(s) and organic acids, and in penetration of the primary roots into gels.

Growth and microtubule orientation of Zea mays roots subjected to osmotic stress

Science.gov (United States)

Blancaflor, E. B.; Hasenstein, K. H.

1995-01-01

Previous work has shown that microtubule (MT) reorientation follows the onset of growth inhibition on the lower side of graviresponding roots, indicating that growth reduction can occur independently of MT reorientation. To test this observation further, we examined whether the reduction in growth in response to osmotic stress is correlated with MT reorientation. The distribution and rate of growth in maize roots exposed to 350 mOsm sorbitol and KCl or 5 mM Mes/Tris buffer were measured with a digitizer. After various times roots were processed for indirect immunofluorescence microscopy. Application of sorbitol or KCl had no effect on the organization of MTs in the apical 2 mm of the root but resulted in striking and different effects in the basal region of the root. Sorbitol treatment caused rapid appearance of oval to circular holes in the microtubular array that persisted for at least 9 h. Between 30 min and 4 h of submersion in KCl, MTs in cortical cells 4 mm and farther from the quiescent center began to reorient oblique to the longitudinal axis. After 9 h, the alignment of MTs had shifted to parallel to the root axis but MTs of the epidermal cells remained transverse. In KCl-treated roots MT reorientation appeared to follow a pattern of development similar to that in controls but without elongation. Our data provide additional evidence that MT reorientation is not the cause but a consequence of growth inhibition.

The effects of nano-TiO{sub 2} on seed germination, development and mitosis of root tip cells of Vicia narbonensis L. and Zea mays L

Energy Technology Data Exchange (ETDEWEB)

Ruffini Castiglione, Monica, E-mail: mruffini@biologia.unipi.it [University of Pisa, Department of Biology (Italy); Giorgetti, Lucia; Geri, Chiara [Institute of Agricultural Biology and Biotechnology (IBBA/CNR), UOS Pisa (Italy); Cremonini, Roberto [University of Pisa, Department of Biology (Italy)

2011-06-15

This study aimed to provide new information about phyto-toxicology of nano-TiO{sub 2} on plant systems. To contribute to the evaluation of the potential harmful effects of the nanoparticles on monocots and dicots we considered their effects on seed germination and root elongation applying a concentration range from 0.2 to 4.0 Per-Mille-Sign in the plants Zea mays L. and Vicia narbonensis L. Moreover, we achieved a genotoxicity study at cytological level in root meristems by means of traditional cytogenetic approach, to evidence possible alterations in mitotic activity, chromosomal aberrations, and micronuclei release. From these analyses it comes out that nano-TiO{sub 2} particles, after short-term exposure and under our experimental conditions, delayed germination progression for the first 24 h in both materials. Root elongation was affected only after treatment with the higher nano-TiO{sub 2} concentration. Further significant effects were detected showing mitotic index reduction and concentration-dependent increase in the aberration emergence that evidenced a nano-TiO{sub 2}-induced genotoxic effect for both species.

Uni-axial Elongational Viscosity of Linear and Branched polymer melts

DEFF Research Database (Denmark)

Hassager, Ole; Nielsen, Jens Kromann; Rasmussen, Henrik Koblitz

2005-01-01

About 40 years ago interest in the measurement of elongational viscosity of polymer melts started to grow. Here we present measurements of transient (and steady) uni-axial elongational viscosity, using the FSR, of the following melts: Four narrow MMD polystyrene (PS) samples with weight......-average molar mass Mw in the range of 50k to 390k. Three different bi-disperse samples, mixed from the narrow MMD PS. Two low-density polyethylene (LDPE) melts (Lupolen 1840D and 3020D). A steady-state viscosity was kept for 1-2.5 Hencky strain units in all measurements.The measurements on the bi-disperse PS...... melts have demonstrated that both the transient and steady elongational viscosity is quite sensitive to polydispersity. Bi-disperse PS resembles the behaviour of mono-disperse melts only at elongational rates larger then the inverse of maximal time constant of the smallest molecule. As observed in Boger...

Role of hormones in controlling vascular differentiation and the mechanism of lateral root initiation.

Science.gov (United States)

Aloni, Roni

2013-11-01

The vascular system in plants is induced and controlled by streams of inductive hormonal signals. Auxin produced in young leaves is the primary controlling signal in vascular differentiation. Its polar and non-polar transport pathways and major controlling mechanisms are clarified. Ethylene produced in differentiating protoxylem vessels is the signal that triggers lateral root initiation, while tumor-induced ethylene is a limiting and controlling factor of crown gall development and its vascular differentiation. Gibberellin produced in mature leaves moves non-polarly and promotes elongation, regulates cambium activity and induces long fibers. Cytokinin from the root cap moves upward to promote cambial activity and stimulate shoot growth and branching, while strigolactone from the root inhibits branching. Furthermore, the role of the hormonal signals in controlling the type of differentiating vascular elements and gradients of conduit size and density, and how they regulate plant adaptation and have shaped wood evolution are elucidated.

On the role of MT1-MMP, a matrix metalloproteinase essential to collagen remodeling, in murine molar eruption and root growth

NARCIS (Netherlands)

Beertsen, Wouter; Holmbeck, Kenn; Niehof, Anneke; Bianco, Paolo; Chrysovergis, Kaliiopi; Birkedal-Hansen, Henning; Everts, Vincent

2002-01-01

Although the connective tissues of the periodontium are subject to a high turnover rate, no conclusive evidence has yet emerged that periodontal collagen turnover is essential for the eruption of teeth or for root elongation. These processes were studied in mice deficient in MT1-MMP, a membrane type

Growth and graviresponsiveness of primary roots of Zea mays seedlings deficient in abscisic acid and gibberellic acid

Science.gov (United States)

Moore, R.; Dickey, K.

1985-01-01

The objective of this research was to determine if gibberellic acid (GA) and/or abscisic acid (ABA) are necessary for graviresponsiveness by primary roots of Zea mays. To accomplish this objective we measured the growth and graviresponsiveness of primary roots of seedlings in which the synthesis of ABA and GA was inhibited collectively and individually by genetic and chemical means. Roots of seedlings treated with Fluridone (an inhibitor of ABA biosynthesis) and Ancymidol (an inhibitor of GA biosynthesis) were characterized by slower growth rates but not significantly different gravicultures as compared to untreated controls. Gravicurvatures of primary roots of d-5 mutants (having undetectable levels of GA) and vp-9 mutants (having undectable levels of ABA) were not significantly different from those of wild-type seedlings. Roots of seedlings in which the biosynthesis of ABA and GA was collectively inhibited were characterized by gravicurvatures not significantly different for those of controls. These results (1) indicate that drastic reductions in the amount of ABA and GA in Z. mays seedlings do not significantly alter root graviresponsiveness, (2) suggest that neither ABA nor GA is necessary for root gravicurvature, and (3) indicate that root gravicurvature is not necessarily proportional to root elongation.

Identification of qSOR1, a major rice QTL involved in soil-surface rooting in paddy fields.

Science.gov (United States)

Uga, Yusaku; Hanzawa, Eiko; Nagai, Shinsei; Sasaki, Kazuhiro; Yano, Masahiro; Sato, Tadashi

2012-01-01

Specific Indonesian lowland rice (Oryza sativa L.) cultivars elongate thick primary roots on the soil surface of paddy fields. To clarify the genetic factors controlling soil-surface rooting, we performed quantitative trait locus (QTL) analyses using 124 recombinant inbred lines (RILs) derived from a cross between Gemdjah Beton, an Indonesian lowland rice cultivar with soil-surface roots, and Sasanishiki, a Japanese lowland rice cultivar without soil-surface roots. These cultivars and the RILs were tested for soil-surface rooting in a paddy field. We identified four regions of chromosomes 3, 4, 6, and 7 that were associated with soil-surface rooting in the field. Among them, one major QTL was located on the long arm of chromosome 7. This QTL explained 32.5-53.6% of the total phenotypic variance across three field evaluations. To perform fine mapping of this QTL, we measured the basal root growth angle of crown roots at the seedling stage in seven BC(2)F(3) recombinant lines grown in small cups in a greenhouse. The QTL was mapped between markers RM21941 and RM21976, which delimit an 812-kb interval in the reference cultivar Nipponbare. We have designated this QTL qSOR1 (quantitative trait locus for SOIL SURFACE ROOTING 1).

Can early aortic root surgery prevent further aortic dissection in Marfan syndrome?

OpenAIRE

Shimizu, Hideyuki; Kasahara, Hirofumi; Nemoto, Atsushi; Yamabe, Kentaro; Ueda, Toshihiko; Yozu, Ryohei

2011-01-01

We reviewed 50 patients with Marfan syndrome who underwent surgery for aortic root pathologies comprising a root aneurysm without (n = 25; group A) and with (n = 25; group B) dissection. Aortic root repair included Bentall (n = 37) and valve-sparing (n = 13) procedures. Hospital mortality was 4.0%. Twenty-two patients required 36 repeat surgeries on the distal aorta. The main indication for re-intervention was the dilation of the false lumen. In group A, the distal aorta was stable for up to ...

Light quality and elongation growth. 1: Effect of duration and time of far red irradiation on stem elongation of Argyranthemum frutescens cv. Silver Leaf

International Nuclear Information System (INIS)

Jatzkowski, M.; Zimmer, K.

1994-01-01

The phenomenon of stem elongation by far red irradiation was shown with Argyranthemum frutescens 'Silver Leaf'. Stem elongation was promoted by incandescent lighting (mainly far red) during the day and night period. More intense reactions were observed with the isolated application during the nighttime. Reaction was strongly modified by the point of time the application took place. No effect could be shown by lighting with incandescent lamps for two hours during the daytime given within the first six hours of the main light period. During the nighttime two hours of lighting (incandescent lamps) promoted stem elongation atany point of time, especially in the middle of the dark period

Scattering phaseshift formulas for mesons and baryons in elongated boxes

Science.gov (United States)

Lee, Frank X.; Alexandru, Andrei

2018-03-01

We derive Lüscher phaseshift formulas for two-particle states in boxes elongated in one of the dimensions. Such boxes offer a cost-effective way of varying the relative momentum of the particles. Boosted states in the elongated direction, which allow wider access to energies, are also considered. The formulas for the various scenarios (moving and zero-momentum states in cubic and elongated boxes) are compared and relations between them are clarified. The results are applicable to a wide set of meson-meson and meson-baryon elastic scattering processes, with the two-particle system having equal or unequal masses.

Discontinuation of orthokeratology on eyeball elongation (DOEE).

Science.gov (United States)

Cho, P; Cheung, S W

2017-04-01

To evaluate and compare changes in axial elongation, over a 14-month period, in subjects who discontinued and then resumed ortho-k lens wear with those who continued to wear their lenses or spectacles following a 2-year myopia control study. This single masked, prospective study recruited subjects who had just completed a 2-year myopia control study. Ortho-k subjects were classified as Group OKc, in which subjects continued ortho-k lens wear for the duration of the study; or Group OKd in which subjects discontinued lens wear for seven months and wore single-vision spectacles (Phase I) and then resumed ortho-k lens wear for another seven months (Phase II). Spectacle-wearing control subjects from the initial myopia control study continued wearing spectacles as control subjects. Axial lengths were measured at scheduled visits using the IOLMaster. Thirteen, 16, and 15 Control, OKc, and OKd subjects, aged 8-14 years, respectively completed the study. Significant increase in axial elongation was found in OKd subjects only in Phase I but not in Phase II. On resuming lens wear, in Phase II, the rate of axial elongation was no longer significantly different from those of the Control or OKc subjects. Stopping ortho-k lens wear at or before the age of 14 years led to a more rapid increase in axial length; comparable to those wearing spectacles during the initial 2-year myopia control study, but greater than the Control and OKc group in this study. Axial elongation slowed again with resumed lens wear after six months. Copyright © 2016 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

Viscosity overshoot in the start-up of uniaxial elongation of low density polyethylene melts

DEFF Research Database (Denmark)

Rasmussen, Henrik K.; Nielsen, Jens Kromann; Bach, Anders

2005-01-01

The transient uniaxial elongational viscosity of BASF Lupolen 1840D and 3020D melts has been measured on a filament stretch rheometer up to Hencky strains of 6-7. The elongational viscosity of both melts was measured at 130 degrees C within a broad range of elongational rates. At high elongation ...

Photo-oxidation of LDPE: Effects on elongational viscosity

Science.gov (United States)

Rolón-Garrido, Víctor H.; Wagner, Manfred H.

2013-04-01

Sheets of low-density polyethylene (LDPE) were photo-oxidatively treated at room temperature, and subsequently characterized rheologically in the melt state by shear and uniaxial extensional experiments. For photo-oxidation, a xenon lamp was used to irradiate the samples for times between 1 day and 6 weeks. Linear-viscoelastic characterization was performed in a temperature range of 130 to 220°C to obtain the master curve at 170°C, the reference temperature at which the elongational viscosities were measured. Linear viscoelasticity is increasingly affected by increasing photo-oxidation due to crosslinking of LDPE, as corroborated by an increasing gel fraction as determined by a solvent extraction method. The elongational measurements reveal a strong enhancement of strain hardening until a saturation level is achieved. The elongational data are analyzed in the frame work of two constitutive equations, the rubber-like liquid and the molecular stress function models. Within the experimental window, time-deformation separability is confirmed for all samples, independent of the degree of photo-oxidation.

A root cause analysis project in a medication safety course.

Science.gov (United States)

Schafer, Jason J

2012-08-10

To develop, implement, and evaluate team-based root cause analysis projects as part of a required medication safety course for second-year pharmacy students. Lectures, in-class activities, and out-of-class reading assignments were used to develop students' medication safety skills and introduce them to the culture of medication safety. Students applied these skills within teams by evaluating cases of medication errors using root cause analyses. Teams also developed error prevention strategies and formally presented their findings. Student performance was assessed using a medication errors evaluation rubric. Of the 211 students who completed the course, the majority performed well on root cause analysis assignments and rated them favorably on course evaluations. Medication error evaluation and prevention was successfully introduced in a medication safety course using team-based root cause analysis projects.

Bilateral elongated styloid process: Its anatomical, embryological and clinical implications

Directory of Open Access Journals (Sweden)

Bagoji Ishwar B, Hadimani Gavishiddappa A, Patil Balasaheb G, Bannur Balappa M,Ambadasu B

2013-04-01

Full Text Available The styloid process is a slender, elongated, cylindrical bony projection from temporal bone. It normally varies in length from 2 cm to 3 cm. During a routine demonstration of skull for MBBS students we found the bilateral elongated styloid process in dry human skull. The length of elongation measured on the right and left side was 6.0 & 5.9 cms respectively. Such abnormal elongation of the styloid process may cause compression on a number of vital vessels and nerves related to it, producing inflammatory changes that include continuous chronic pain in the pharyngeal region. Mechanical stresses stretching the second brachial arch during fetal development probably induce variable involvement of Reichert’s cartilage in morphogenesis of the styloid process. It is important that clinicians especially dentists and otolaryngologists are aware of the natural variations of the styloid process and do not consider the styloid process with a length of 30 mm as an abnormality or as an anomaly.

Innate Immune Responses Activated in Arabidopsis Roots by Microbe-Associated Molecular Patterns[W][OA

Science.gov (United States)

Millet, Yves A.; Danna, Cristian H.; Clay, Nicole K.; Songnuan, Wisuwat; Simon, Matthew D.; Werck-Reichhart, Danièle; Ausubel, Frederick M.

2010-01-01

Despite the fact that roots are the organs most subject to microbial interactions, very little is known about the response of roots to microbe-associated molecular patterns (MAMPs). By monitoring transcriptional activation of β-glucuronidase reporters and MAMP-elicited callose deposition, we show that three MAMPs, the flagellar peptide Flg22, peptidoglycan, and chitin, trigger a strong tissue-specific response in Arabidopsis thaliana roots, either at the elongation zone for Flg22 and peptidoglycan or in the mature parts of the roots for chitin. Ethylene signaling, the 4-methoxy-indole-3-ylmethylglucosinolate biosynthetic pathway, and the PEN2 myrosinase, but not salicylic acid or jasmonic acid signaling, play major roles in this MAMP response. We also show that Flg22 induces the cytochrome P450 CYP71A12-dependent exudation of the phytoalexin camalexin by Arabidopsis roots. The phytotoxin coronatine, an Ile-jasmonic acid mimic produced by Pseudomonas syringae pathovars, suppresses MAMP-activated responses in the roots. This suppression requires the E3 ubiquitin ligase COI1 as well as the transcription factor JIN1/MYC2 but does not rely on salicylic acid–jasmonic acid antagonism. These experiments demonstrate the presence of highly orchestrated and tissue-specific MAMP responses in roots and potential pathogen-encoded mechanisms to block these MAMP-elicited signaling pathways. PMID:20348432

Amyloplast Distribution Directs a Root Gravitropic Reaction

Science.gov (United States)

Kordyum, Elizabeth

Immobile higher plants are oriented in the gravitational field due to gravitropim that is a physiological growth reaction and consists of three phases: reception of a gravitational signal by statocytes, its transduction to the elongation zone, and finally the organ bending. As it is known, roots are characterized with positive gravitropism, i. e. they grow in the direction of a gravitational vector, stems - with negative gravitropism, i. e. they grow in the direction opposite to a gravitational vector. According to the Nemec’s and Haberlandt’s starch-statolith hypothesis, amyloplasts in diameter of 1.5 - 3 μ in average, which appear to act as gravity sensors and fulfill a statolythic function in the specialized graviperceptive cells - statocytes, sediment in the direction of a gravitational vector in the distal part of a cell, while a nucleus is in the proximal one. There are reasonable data that confirm the amyloplasts-statoliths participation in gravity perception: 1) correlation between the statoliths localization and the site of gravity sensing, 2) significant redistribution (sedimentation) of amyloplasts in statocytes under gravistimulation in comparison with other cell organelles, 3) root decreased ability to react on gravity under starch removal from amyloplasts, 4) starchless Arabidopsis thaliana mutants are agravitropic, 5) amyloplasts-statoliths do not sediment in the absence of the gravitational vector and are in different parts or more concentrated in the center of statocytes. Plant tropisms have been intensively studied for many decades and continue to be investigated. Nevertheless, the mechanisms by which plants do so is still not clearly explained and many questions on gravisensing and graviresponse remain unanswered. Even accepted hypotheses are now being questioned and recent data are critically evaluated. Although the available data show the Ca2+ and cytoskeleton participation in graviperception and signal transduction, the clear evidence

An Equatorial Contractile Mechanism Drives Cell Elongation but not Cell Division

Science.gov (United States)

Denker, Elsa; Bhattachan, Punit; Deng, Wei; Mathiesen, Birthe T.; Jiang, Di

2014-01-01

Cell shape changes and proliferation are two fundamental strategies for morphogenesis in animal development. During embryogenesis of the simple chordate Ciona intestinalis, elongation of individual notochord cells constitutes a crucial stage of notochord growth, which contributes to the establishment of the larval body plan. The mechanism of cell elongation is elusive. Here we show that although notochord cells do not divide, they use a cytokinesis-like actomyosin mechanism to drive cell elongation. The actomyosin network forming at the equator of each notochord cell includes phosphorylated myosin regulatory light chain, α-actinin, cofilin, tropomyosin, and talin. We demonstrate that cofilin and α-actinin are two crucial components for cell elongation. Cortical flow contributes to the assembly of the actomyosin ring. Similar to cytokinetic cells, membrane blebs that cause local contractions form at the basal cortex next to the equator and participate in force generation. We present a model in which the cooperation of equatorial actomyosin ring-based constriction and bleb-associated contractions at the basal cortex promotes cell elongation. Our results demonstrate that a cytokinesis-like contractile mechanism is co-opted in a completely different developmental scenario to achieve cell shape change instead of cell division. We discuss the occurrences of actomyosin rings aside from cell division, suggesting that circumferential contraction is an evolutionally conserved mechanism to drive cell or tissue elongation. PMID:24503569

Glycan elongation beyond the mucin associated Tn antigen protects tumor cells from immune-mediated killing

DEFF Research Database (Denmark)

Madsen, Caroline B; Lavrsen, Kirstine; Steentoft, Catharina

2013-01-01

are recognized as cancer associated truncated glycans, and are expressed in many adenocarcinomas, e.g. breast- and pancreatic cancer cells. To investigate the role of the cancer associated glycan truncations in immune-mediated killing we created glyco-engineered breast- and pancreatic cancer cells expressing...... only the shortest possible mucin-like glycans (Tn and STn). Glyco-engineering was performed by zinc finger nuclease (ZFN) knockout (KO) of the Core 1 enzyme chaperone COSMC, thereby preventing glycan elongation beyond the initial GalNAc residue in O-linked glycans. We find that COSMC KO in the breast...

Ninjin'yoeito and ginseng extract prevent oxaliplatin-induced neurodegeneration in PC12 cells.

Science.gov (United States)

Suzuki, Toshiaki; Yamamoto, Ayano; Ohsawa, Masahiro; Motoo, Yoshiharu; Mizukami, Hajime; Makino, Toshiaki

2015-10-01

Ninjin'yoeito (NYT) is a formula of Japanese traditional kampo medicine composed of 12 crude drugs, and is designed to improve the decline in constitution after recovery from disease, fatigue, anemia, anorexia, perspiration during sleep, cold limbs, slight fever, chills, persistent cough, malaise, mental disequilibrium, insomnia, and constipation. Oxaliplatin (L-OHP) is a platinum-based anticancer drug used to treat colorectal, pancreatic, and stomach cancers. However, it often causes acute and chronic peripheral neuropathies including cold allodynia and mechanical hyperalgesia. In this study, we investigated the preventive effects of NYT on neuronal degeneration caused by L-OHP using PC12 cells, which are derived from the rat adrenal medulla and differentiate into nerve-like cells after exposure to nerve growth factor. L-OHP treatment decreased the elongation of neurite-like projection outgrowths in differentiated PC12 cells. When PC12 cells were treated with NYT hot water extract, neurodegeneration caused by L-OHP was significantly prevented in a concentration-dependent manner. Among the 12 crude drugs composing NYT, the extract of Ginseng (the root of Panax ginseng) exhibited the strongest preventive effects on neurodegeneration in differentiated PC12 cells. By activity-guided fractionation, we found that the fraction containing ginsenosides displayed preventive activity and, among several ginsenosides, ginsenoside F2 exhibited significant preventive effects on L-OHP-induced decreases in neurite-like outgrowths in differentiated PC12 cells. These results suggest that NYT and ginseng are promising agents for preventing L-OHP-induced neuropathies and present ginsenoside F2 as one of the active ingredients in ginseng.

Extensive tissue-specific transcriptomic plasticity in maize primary roots upon water deficit.

Science.gov (United States)

Opitz, Nina; Marcon, Caroline; Paschold, Anja; Malik, Waqas Ahmed; Lithio, Andrew; Brandt, Ronny; Piepho, Hans-Peter; Nettleton, Dan; Hochholdinger, Frank

2016-02-01

Water deficit is the most important environmental constraint severely limiting global crop growth and productivity. This study investigated early transcriptome changes in maize (Zea mays L.) primary root tissues in response to moderate water deficit conditions by RNA-Sequencing. Differential gene expression analyses revealed a high degree of plasticity of the water deficit response. The activity status of genes (active/inactive) was determined by a Bayesian hierarchical model. In total, 70% of expressed genes were constitutively active in all tissues. In contrast, deficit-responsive genes (1915) were consistently regulated in all tissues, while >75% (1501 genes) were specifically regulated in a single root tissue. Water deficit-responsive genes were most numerous in the cortex of the mature root zone and in the elongation zone. The most prominent functional categories among differentially expressed genes in all tissues were 'transcriptional regulation' and 'hormone metabolism', indicating global reprogramming of cellular metabolism as an adaptation to water deficit. Additionally, the most significant transcriptomic changes in the root tip were associated with cell wall reorganization, leading to continued root growth despite water deficit conditions. This study provides insight into tissue-specific water deficit responses and will be a resource for future genetic analyses and breeding strategies to develop more drought-tolerant maize cultivars. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Adherens junction distribution mechanisms during cell-cell contact elongation in Drosophila.

Directory of Open Access Journals (Sweden)

Gabrielle Goldenberg

Full Text Available During Drosophila gastrulation, amnioserosa (AS cells flatten and spread as an epithelial sheet. We used AS morphogenesis as a model to investigate how adherens junctions (AJs distribute along elongating cell-cell contacts in vivo. As the contacts elongated, total AJ protein levels increased along their length. However, genetically blocking this AJ addition indicated that it was not essential for maintaining AJ continuity. Implicating other remodeling mechanisms, AJ photobleaching revealed non-directional lateral mobility of AJs along the elongating contacts, as well as local AJ removal from the membranes. Actin stabilization with jasplakinolide reduced AJ redistribution, and live imaging of myosin II along elongating contacts revealed fragmented, expanding and contracting actomyosin networks, suggesting a mechanism for lateral AJ mobility. Actin stabilization also increased total AJ levels, suggesting an inhibition of AJ removal. Implicating AJ removal by endocytosis, clathrin endocytic machinery accumulated at AJs. However, dynamin disruption had no apparent effect on AJs, suggesting the involvement of redundant or dynamin-independent mechanisms. Overall, we propose that new synthesis, lateral diffusion, and endocytosis play overlapping roles to populate elongating cell-cell contacts with evenly distributed AJs in this in vivo system.

Expressed proteins of Herbaspirillum seropedicae in maize (DKB240) roots-bacteria interaction revealed using proteomics.

Science.gov (United States)

Ferrari, Cibele Santos; Amaral, Fernanda Plucani; Bueno, Jessica Cavalheiro Ferreira; Scariot, Mirella Christine; Valentim-Neto, Pedro Alexandre; Arisi, Ana Carolina Maisonnave

2014-11-01

Several molecular tools have been used to clarify the basis of plant-bacteria interaction; however, the mechanism behind the association is still unclear. In this study, we used a proteomic approach to investigate the root proteome of Zea mays (cv. DKB240) inoculated with Herbaspirillum seropedicae strain SmR1 grown in vitro and harvested 7 days after inoculation. Eighteen differentially accumulated proteins were observed in root samples, ten of which were identified by MALDI-TOF mass spectrometry peptide mass fingerprint. Among the identified proteins, we observed three proteins present exclusively in inoculated root samples and six upregulated proteins and one downregulated protein relative to control. Differentially expressed maize proteins were identified as hypothetical protein ZEAMMB73_483204, hypothetical protein ZEAMMB73_269466, and tubulin beta-7 chain. The following were identified as H. seropedicae proteins: peroxiredoxin protein, EF-Tu elongation factor protein, cation transport ATPase, NADPH:quinone oxidoreductase, dinitrogenase reductase, and type III secretion ATP synthase. Our results presented the first evidence of type III secretion ATP synthase expression during H. seropedicae-maize root interaction.

(R)-β-lysine-modified elongation factor P functions in translation elongation

DEFF Research Database (Denmark)

Bullwinkle, Tammy J; Zou, S Betty; Rajkovic, Andrei

2013-01-01

Post-translational modification of bacterial elongation factor P (EF-P) with (R)-β-lysine at a conserved lysine residue activates the protein in vivo and increases puromycin reactivity of the ribosome in vitro. The additional hydroxylation of EF-P at the same lysine residue by the YfcM protein has......-(β)-lysyl-EF-P showed 30% increased puromycin reactivity but no differences in dipeptide synthesis rates when compared with the β-lysylated form. Unlike disruption of the other genes required for EF-P modification, deletion of yfcM had no phenotypic consequences in Salmonella. Taken together, our findings indicate...

Methanol as an alternative electron donor in chain elongation for butyrate and caproate formation

OpenAIRE

Chen, W.S.; Ye, Y.; Steinbusch, K.J.J.; Strik, D.P.B.T.B.; Buisman, C.J.N.

2016-01-01

Chain elongation is an emerging mixed culture biotechnology converting acetate into valuable biochemicals by using ethanol as an external electron donor. In this study we proposed to test another potential electron donor, methanol, in chain elongation. Methanol can be produced through the thermochemical conversion of lignocellulosic biowaste. Use of methanol in chain elongation integrates the lignocellulosic feedstocks and the thermochemical platform technologies into chain elongation. After ...

Status of the tube elongation problem as of June 1976

International Nuclear Information System (INIS)

Alexander, W.K.

1976-01-01

It was discovered in May of 1971 that the N Reactor process tubes had apparently increased in length by as much as one inch. Preliminary observations and measurements led to the tentative conclusion that this observed elongation was linear with accumulated tube exposure and also that it was related in some manner to the tube fabrication process. It appeared that the observed elongation was approximately proportional to the degree of cold work retained in the finished tubes. This latter conclusion was based on the observation that those tubes with approximately 17-18 percent cold work had elongated only about half as much as the standard 30-percent-cold-worked tubes. It was immediately recognized that if such elongation was to continue unchecked it could pose a limit to reactor life since total possible tube expansion, from all causes, is limited to 1.75 inches by nozzle design considerations as shown in Figure 1. Thermal and hydraulic expansion were calculated to total approximately 0.75 inches which left only one inch available to accommodate tube growth or creep. Since discovery of this phenomenon, an extensive measurements program has been carried out to evaluate the extent and rate of tube elongation. Two corrective approaches have been developed and a small number of tubes were modified by each method during the 1976 summer outage. During the 1974, 1975 and 1976 Summer Outages, measurements were made on all tubes to determine the clearance remaining between the nozzle keys and the gas packing ring. These readings not only give an overall picture of the extent of elongation, but also provide immediate data indicating which tubes are about out of clearance. The report presents an evaluation of the measurements taken to date

First record of plicidentine in Synapsida and patterns of tooth root shape change in Early Permian sphenacodontians.

Science.gov (United States)

Brink, Kirstin S; LeBlanc, Aaron R H; Reisz, Robert R

2014-11-01

Recent histological studies have revealed a diversity of dental features in Permo-Carboniferous tetrapods. Here, we report on the occurrence of plicidentine (infolded dentine around the base of the tooth root) in Sphenacodontia, the first such documentation in Synapsida, the clade that includes mammals. Five taxa were examined histologically, Ianthodon schultzei, Sphenacodon ferocior, Dimetrodon limbatus, Dimetrodon grandis, and Secodontosaurus obtusidens. The tooth roots of Ianthodon possess multiple folds, which is generally viewed as the primitive condition for amniotes. Sphenacodon and D. limbatus have distinctive "four-leaf clover"-shaped roots in cross section, whereas Secodontosaurus has an elongate square shape with only subtle folding. The most derived and largest taxon examined in this study, D. grandis, has rounded roots in cross section and therefore no plicidentine. This pattern of a loss of plicidentine in sphenacodontids supports previous functional hypotheses of plicidentine, where teeth with shallow roots require folds to increase the area of attachment to the tooth-bearing element, whereas teeth with long roots do not. This pattern may also reflect differences in diet between co-occurring sphenacodontids as well as changes in feeding niche through time, specifically in the apex predator Dimetrodon.

Macroscopic and radiographic examination of proximal root surface caries

International Nuclear Information System (INIS)

Nordenram, G.; Bergvist, A.; Johnson, G.; Henriksen, C.O.; Anneroth, G.

1988-01-01

The purpose of the study was to compare macroscopic and radiographic examination of proximal root surface caries of extracted teeth from patients aged 65-95 years. Although the study conditions for macroscopic and radiographic diagnosis favored more sensitive evaluations than routine clinical conditions, there was a 24% disagreement in diagnosis. This finding indicates that under routine clinical conditions it is difficult to register with certainty all superficial root carious lesions. Even in the absence of clinically detectable root surface caries, preventive measures should be considered for elderly people with exposed root surfaces

Rhizome elongation and seagrass clonal growth

NARCIS (Netherlands)

Marbà, N.; Duarte, C.M.

1998-01-01

A compilation of published and original data on rhizome morphometry, horizontal and vertical elongation rates and branching patterns for 27 seagrass species developing in 192 seagrass stands allowed an examination of the variability of seagrass rhizome and clonal growth programmes across and within

Chemical ionization mass spectrometry of indol-3yl-acetic acid and cis-abscisic acid: evaluation of negative ion detection and quantification of cis-abscisic acid in growing maize roots

International Nuclear Information System (INIS)

Rivier, L.; Saugy, M.

1986-01-01

Mass spectra of the derivatives of indol-3yl-acetic acid and cis-abscisic acid were obtained in electron impact and chemical ionization positive ion and negative ion modes. The respective merits of methane, isobutane, and ammonia as reagent gases for structure determination and sensitive detection were compared using the methyl esters. From one to 10 fluorine atoms were attached to IAA to improve the electron-capturing properties of the molecule. The best qualitative information was obtained when using positive ion chemical ionization with methane. However, the most sensitive detection, with at least two ions per molecule, was achieved by electron impact on the IAA-HFB-ME derivative and by negative ion chemical ionization with NH 3 on the ABA-methyl ester derivative. p ]Quantitative analyses of ABA in different parts of maize (Zea mays cv. LG 11) root tips were performed by the latter technique. It was found that the cap and apex contained less ABA than the physiologically older parts of the root such as the elongation zone and the more differentiated tissues. This technique was also used to show a relation between maize root growth and the endogenous ABA level of the elongation zone and root tip: there is more ABA in the slowly growing roots than in the rapidly growing ones. (author)

Incremental elongation or ratchetting - Experimental tests and practical method of analysis (on stainless steel 304L and 306L)

International Nuclear Information System (INIS)

Cousseran, Pierre; Lebey, Jacques; Roche, Roland; Clement, Gerard; Moulin, Didier.

1980-12-01

Ratchetting, or incremental elongation can be considered as a creep enhancement when cyclic deformations are added to a primary constant load. Under examination, it appears that theoretical models proposed till now do not fit correctly the actual behavior of materials. From experimental tests results performed in Saclay, a simplified method for prevention of ratcheting is proposed. A validation was made by using experimental data from various sources [fr

Amphiregulin Antibody and Reduction of Axial Elongation in Experimental Myopia

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Wen Jun Jiang

2017-03-01

Full Text Available To examine the mechanism of ocular axial elongation in myopia, guinea pigs (age: 2–3 weeks which either underwent unilateral or bilateral lens-induced myopization (group 1 or which were primarily myopic at baseline (group 2 received unilateral intraocular injections of amphiregulin antibody (doses: 5, 10, or 15 μg three times in intervals of 9 days. A third group of emmetropic guinea pigs got intraocular unilateral injections of amphiregulin (doses: 0.25, 0.50 or 1.00 ng, respectively. In each group, the contralateral eyes received intraocular injections of Ringer's solution. In intra-animal inter-eye comparison and intra-eye follow-up comparison in groups 1 and 2, the study eyes as compared to the contralateral eyes showed a dose-dependent reduction in axial elongation. In group 3, study eyes and control eyes did not differ significantly in axial elongation. Immunohistochemistry revealed amphiregulin labelling at the retinal pigment epithelium in eyes with lens-induced myopization and Ringer's solution injection, but not in eyes with amphiregulin antibody injection. Intraocular injections of amphiregulin-antibody led to a reduction of lens-induced axial myopic elongation and of the physiological eye enlargement in young guinea pigs. In contrast, intraocularly injected amphiregulin in a dose of ≤1 ng did not show a significant effect. Amphiregulin may be one of several essential molecular factors for axial elongation.

Impaired rate of microsomal fatty acid elongation in undernourished neonatal rat brain

International Nuclear Information System (INIS)

Yeh, Y.Y.

1986-01-01

Hypomyelination caused by undernourishment in characterized by low concentrations of myelin lipids and marked reduction in lignocerate (C/sub 24:0/) and nervonate (C/sub 24:1/) moiety of cerebroside and sulfatide. Since microsomal elongation is the major source of long chain (22 to 24 carbons) fatty acids in the brain, the effect of neonatal undernourishment on acyl elongation was investigated. Undernourishment of suckling rats were induced after birth by restricting maternal dietary intake to 40% of that consumed by dams fed ad libitum. Neonates suckled by the normally fed dams served as controls. Microsomal elongation was measured as nmol from [2- 14 C] malonyl CoA incorporated/h per mg of protein. At 19 days of age, rates of behenoyl CoA (C/sub 22:0/) and erucoyl CoA (C/sub 22:1/) elongation in whole brain of undernourished neonates were 30-40% lower than that of the control, whereas the elongation rates of acyl CoA 16, 18 and 20 carbons in length either saturated or monounsaturated were similar in both groups. Undernourishment had no effect on cytoplasmic de novo fatty acid synthesis from acetyl CoA. If there are multiple elongation factors, the results indicate that the depressed activity of elongating enzyme(s) for C/sub 22:0/ and C/sub 22:1/ is an important contributing factor in lowering S/sub 24:0/ and C/sub 24:1/ content in cerebroside and sulfatide. This impairment may be a specific lesion leading to hypomyelination in undernourished rats

Endodontic Treatment in Submerged Roots: A Case Report

Directory of Open Access Journals (Sweden)

Hemalatha Pameshwar Hiremath

2010-06-01

Full Text Available Alveolar ridge resorption has long been considered an unavoidable consequence of tooth extraction. While the extent and pattern of resorption is variable among individuals, there is a progressive loss of ridge contour as a result of physiologic bone remodeling. Even today, with best modalities of tooth preservation, there is a group of elderly individuals who do not benefit from modern preventive practices and who now present a dilemma in terms of maintaining the masticatory apparatus necessary for nutrition. Even with excellent dental care, such patients experience abrasion of the natural tooth crowns with age, and embedded roots are left within the alveolar bone. According to old concepts of dental care, extraction of these roots would have been recommended, but today’s goal of excellence in endodontics dictates otherwise. We report a case in which vital and non-vital root submergence was carried out to prevent alveolar ridge reduction.

Analysis of AtGUS1 and AtGUS2 in Arabidopsis root apex by a highly sensitive TSA-MISH method.

Science.gov (United States)

Bruno, Leonardo; Ronchini, Matteo; Gagliardi, Olimpia; Corinti, Tamara; Chiappetta, Adriana; Gerola, Paolo; Bitonti, Maria B

2015-01-01

A new highly sensitive whole-mount in situ hybridization method, based on tyramide signal amplification (TSA-MISH) was developed and a combined GFP detection and TSA-MISH procedure was applied for the first time in plants, to precisely define the spatial pattern of AtGUS1 and AtGUS2 expression in the root apex. β-glucuronidases (GUSs) belonging to the glycosyl hydrolases (GHs) 79 family, are widely distributed in plants, but their functional role has not yet been fully investigated. In the model system Arabidopsis Thaliana, three different AtGUS genes have been identified which encode proteins with putative different fates. Endogenous GUS expression has been detected in different organs and tissues, but the cyto-histological domains of gene expression remain unclear. The results here reported show co-expression of AtGUS1 and AtGUS2 in different functional zones of the root apex (the cap central zone, the root cap meristem, the staminal cell niche and the cortical cell layers of the proximal meristem), while AtGUS2 is exclusively expressed in the cap peripheral layer and in the epidermis in the elongation zone. Interestingly, both genes are not expressed in the stelar portion of the proximal meristem. A spatial (cortex vs. stele) and temporal (proximal meristem vs. transition zone) regulation of AtGUS1 and AtGUS2 expression is therefore active in the root apex. This expression pattern, although globally consistent with the involvement of GUS activity in both cell proliferation and elongation, clearly indicates that AtGUS1 and AtGUS2 could control distinct downstream process depending on the developmental context and the interaction with other players of root growth control. In the future, the newly developed approaches may well be very useful to dissect such interactions.

Eukaryotic elongation factor 2 controls TNF-α translation in LPS-induced hepatitis

Science.gov (United States)

González-Terán, Bárbara; Cortés, José R.; Manieri, Elisa; Matesanz, Nuria; Verdugo, ρngeles; Rodríguez, María E.; González-Rodríguez, ρgueda; Valverde, ρngela; Martín, Pilar; Davis, Roger J.; Sabio, Guadalupe

2012-01-01

Bacterial LPS (endotoxin) has been implicated in the pathogenesis of acute liver disease through its induction of the proinflammatory cytokine TNF-α. TNF-α is a key determinant of the outcome in a well-established mouse model of acute liver failure during septic shock. One possible mechanism for regulating TNF-α expression is through the control of protein elongation during translation, which would allow rapid cell adaptation to physiological changes. However, the regulation of translational elongation is poorly understood. We found that expression of p38γ/δ MAPK proteins is required for the elongation of nascent TNF-α protein in macrophages. The MKK3/6-p38γ/δ pathway mediated an inhibitory phosphorylation of eukaryotic elongation factor 2 (eEF2) kinase, which in turn promoted eEF2 activation (dephosphorylation) and subsequent TNF-α elongation. These results identify a new signaling pathway that regulates TNF-α production in LPS-induced liver damage and suggest potential cell-specific therapeutic targets for liver diseases in which TNF-α production is involved. PMID:23202732

Spatial Regulation of Root Growth: Placing the Plant TOR Pathway in a Developmental Perspective

Science.gov (United States)

Barrada, Adam; Montané, Marie-Hélène; Robaglia, Christophe; Menand, Benoît

2015-01-01

Plant cells contain specialized structures, such as a cell wall and a large vacuole, which play a major role in cell growth. Roots follow an organized pattern of development, making them the organs of choice for studying the spatio-temporal regulation of cell proliferation and growth in plants. During root growth, cells originate from the initials surrounding the quiescent center, proliferate in the division zone of the meristem, and then increase in length in the elongation zone, reaching their final size and differentiation stage in the mature zone. Phytohormones, especially auxins and cytokinins, control the dynamic balance between cell division and differentiation and therefore organ size. Plant growth is also regulated by metabolites and nutrients, such as the sugars produced by photosynthesis or nitrate assimilated from the soil. Recent literature has shown that the conserved eukaryotic TOR (target of rapamycin) kinase pathway plays an important role in orchestrating plant growth. We will summarize how the regulation of cell proliferation and cell expansion by phytohormones are at the heart of root growth and then discuss recent data indicating that the TOR pathway integrates hormonal and nutritive signals to orchestrate root growth. PMID:26295391

Evaluation of Root Canal Morphology of Human Primary Mandibular ...

African Journals Online (AJOL)

2018-04-04

Apr 4, 2018 ... solution (Omnipaque; Novaplus, Cork, Ireland) to clarify the view of the root canals during CBCT imaging. Each and every root apex was covered with a soft modeling wax to prevent any microleakage of solution, and all teeth were placed in a silicone‑based impression material (Zetaplus, Zhermack, Rovigo, ...

Centrobin-mediated Regulation of the Centrosomal Protein 4.1-associated Protein (CPAP) Level Limits Centriole Length during Elongation Stage*

Science.gov (United States)

Gudi, Radhika; Haycraft, Courtney J.; Bell, P. Darwin; Li, Zihai; Vasu, Chenthamarakshan

2015-01-01

Microtubule-based centrioles in the centrosome mediate accurate bipolar cell division, spindle orientation, and primary cilia formation. Cellular checkpoints ensure that the centrioles duplicate only once in every cell cycle and achieve precise dimensions, dysregulation of which results in genetic instability and neuro- and ciliopathies. The normal cellular level of centrosomal protein 4.1-associated protein (CPAP), achieved by its degradation at mitosis, is considered as one of the major mechanisms that limits centriole growth at a predetermined length. Here we show that CPAP levels and centriole elongation are regulated by centrobin. Exogenous expression of centrobin causes abnormal elongation of centrioles due to massive accumulation of CPAP in the cell. Conversely, CPAP was undetectable in centrobin-depleted cells, suggesting that it undergoes degradation in the absence of centrobin. Only the reintroduction of full-length centrobin, but not its mutant form that lacks the CPAP binding site, could restore cellular CPAP levels in centrobin-depleted cells, indicating that persistence of CPAP requires its interaction with centrobin. Interestingly, inhibition of the proteasome in centrobin-depleted cells restored the cellular and centriolar CPAP expression, suggesting its ubiquitination and proteasome-mediated degradation when centrobin is absent. Intriguingly, however, centrobin-overexpressing cells also showed proteasome-independent accumulation of ubiquitinated CPAP and abnormal, ubiquitin-positive, elongated centrioles. Overall, our results show that centrobin interacts with ubiquitinated CPAP and prevents its degradation for normal centriole elongation function. Therefore, it appears that loss of centrobin expression destabilizes CPAP and triggers its degradation to restrict the centriole length during biogenesis. PMID:25616662

Dro1, a major QTL involved in deep rooting of rice under upland field conditions.

Science.gov (United States)

Uga, Yusaku; Okuno, Kazutoshi; Yano, Masahiro

2011-05-01

Developing a deep root system is an important strategy for avoiding drought stress in rice. Using the 'basket' method, the ratio of deep rooting (RDR; the proportion of total roots that elongated through the basket bottom) was calculated to evaluate deep rooting. A new major quantitative trait locus (QTL) controlling RDR was detected on chromosome 9 by using 117 recombinant inbred lines (RILs) derived from a cross between the lowland cultivar IR64, with shallow rooting, and the upland cultivar Kinandang Patong (KP), with deep rooting. This QTL explained 66.6% of the total phenotypic variance in RDR in the RILs. A BC(2)F(3) line homozygous for the KP allele of the QTL had an RDR of 40.4%, compared with 2.6% for the homozygous IR64 allele. Fine mapping of this QTL was undertaken using eight BC(2)F(3) recombinant lines. The RDR QTL Dro1 (Deeper rooting 1) was mapped between the markers RM24393 and RM7424, which delimit a 608.4 kb interval in the reference cultivar Nipponbare. To clarify the influence of Dro1 in an upland field, the root distribution in different soil layers was quantified by means of core sampling. A line homozygous for the KP allele of Dro1 (Dro1-KP) and IR64 did not differ in root dry weight in the shallow soil layers (0-25 cm), but root dry weight of Dro1-KP in deep soil layers (25-50 cm) was significantly greater than that of IR64, suggesting that Dro1 plays a crucial role in increased deep rooting under upland field conditions.

Elongation factor Ts directly facilitates the formation and disassembly of the Escherichia coli elongation factor Tu·GTP·aminoacyl-tRNA ternary complex.

Science.gov (United States)

Burnett, Benjamin J; Altman, Roger B; Ferrao, Ryan; Alejo, Jose L; Kaur, Navdep; Kanji, Joshua; Blanchard, Scott C

2013-05-10

Aminoacyl-tRNA (aa-tRNA) enters the ribosome in a ternary complex with the G-protein elongation factor Tu (EF-Tu) and GTP. EF-Tu·GTP·aa-tRNA ternary complex formation and decay rates are accelerated in the presence of the nucleotide exchange factor elongation factor Ts (EF-Ts). EF-Ts directly facilitates the formation and disassociation of ternary complex. This system demonstrates a novel function of EF-Ts. Aminoacyl-tRNA enters the translating ribosome in a ternary complex with elongation factor Tu (EF-Tu) and GTP. Here, we describe bulk steady state and pre-steady state fluorescence methods that enabled us to quantitatively explore the kinetic features of Escherichia coli ternary complex formation and decay. The data obtained suggest that both processes are controlled by a nucleotide-dependent, rate-determining conformational change in EF-Tu. Unexpectedly, we found that this conformational change is accelerated by elongation factor Ts (EF-Ts), the guanosine nucleotide exchange factor for EF-Tu. Notably, EF-Ts attenuates the affinity of EF-Tu for GTP and destabilizes ternary complex in the presence of non-hydrolyzable GTP analogs. These results suggest that EF-Ts serves an unanticipated role in the cell of actively regulating the abundance and stability of ternary complex in a manner that contributes to rapid and faithful protein synthesis.

[Effects of combined pollution of lead and benzo[a] pyrene on seed growth of wheat in soils].

Science.gov (United States)

Wang, Hong-Qi; Wang, Shuai; Ning, Shao-Wei; Sun, Yan-Ling; Hou, Ze-Qing

2011-03-01

Seed germination, root elongation, shoot elongation and ratio of shoot to root of wheat in soils polluted by lead (Pb) and benzo (a)pyrene (B[a] P) with medium-low concentrations were studied to reveal the ecological effects of combined pollution and screen the indicative markers. Results indicated that seed germination was not sensitive to single or combined pollution of Pb or B[a] P. Root elongation was inhibited by single pollution of Pb or B[a]P to different extents. Extensive interactions between Pb and B[a]P occurred to root elongation of wheat, including synergistic-stimulatory effect and antagonistic-inhibitory effect. The joint action was mainly antagonistic. Single pollution of B [a] P had an inhibitory effect on shoot elongation. Under combined pollution conditions, the shoot elongation of wheat correlated well with Pb contents (p pollutants had little effect on shoot elongation of wheat. The joint action on shoot elongation was consistently antagonistic. The response pattern of the ratio of shoot to root was similar to the response pattern of shoot elongation. However, the former had better correlation than the latter, indicating it as a more suitable indicative marker for Pb pollution. If lead acetate was employed instead of lead nitrate, longer root elongation, shorter shoot elongation and no effect on ratio of shoot to root were found. Therefore, the forms of Pb salt had significant influence on seed growth of wheat in soils.

Root Cause Analyses of Suicides of Mental Health Clients: Identifying Systematic Processes and Service-Level Prevention Strategies.

Science.gov (United States)

Gillies, Donna; Chicop, David; O'Halloran, Paul

2015-01-01

The ability to predict imminent risk of suicide is limited, particularly among mental health clients. Root cause analysis (RCA) can be used by health services to identify service-wide approaches to suicide prevention. To (a) develop a standardized taxonomy for RCAs; (b) to quantitate service-related factors associated with suicides; and (c) to identify service-related suicide prevention strategies. The RCAs of all people who died by suicide within 1 week of contact with the mental health service over 5 years were thematically analyzed using a data collection tool. Data were derived from RCAs of all 64 people who died by suicide between 2008 and 2012. Major themes were categorized as individual, situational, and care-related factors. The most common factor was that clients had recently denied suicidality. Reliance on carers, recent changes in medication, communication problems, and problems in follow-through were also commonly identified. Given the difficulty in predicting suicide in people whose expressions of suicidal ideation change so rapidly, services may consider the use of strategies aimed at improving the individual, stressor, support, and care factors identified in this study.

Analysis of cracking potential and micro-elongation of linerboard

Directory of Open Access Journals (Sweden)

Supattra Panthai

2016-11-01

Full Text Available Folding cracks of linerboards in relation to their micro-elongation and the forming conditions were studied using an industrial linerboard machine with a top former. The experiments consisted of the study of various forming conditions by manipulating the jet/wire speed ratio to produce linerboard with differences in fiber structures that were related to the cracked and uncracked products. The results showed that changes to the jet/wire speed ratio of about 0.01–0.02 to improve the tested folding endurance in the machine direction potentially produced folding cracks in the linerboard, which indicated an ambiguous interpretation of the foldability tests. The delaminated cracked layers were found to have a high folding endurance and tensile strength, while the decrease in the micro-elongation formulated in this study was found to be related to cracking. A lower micro-elongation of about 350–500 μm/N·g was found in a range of products with folding cracks.

On the decrease of ultimate elongation of gum elastomer by irradiation

International Nuclear Information System (INIS)

Ito, Masayuki

1986-01-01

The reason why the ultimate elongation of gum elastomer decreases by irradiation was studied. The sample used is tetrafluoroethylenepropylene copolymer vulcanized which is a heat resistant elastomer. The sample was irradiated by a electron beam at room temperature. Cross-linking predominate in the operation. (Case 1) Scission predominant condition (Case 2) was given by irradiation of Co-60 γ ray at 100 deg C. Alternative irradiation of γ ray and electron beam under above condition can keep the original cross-linking density by the appropriate choice of each of the doses. (Case 3) The three cases mentioned above involve all of the cases of radiation induced aging of elastomers. Therefor, the following explanation for three cases shows the reason why the ultimate elongation of gum elastomer decreases by irradiation. Case 1. Cross-linking predominant condition. Ultimate elongation is proportional to -0.5 power of the dose. This fact can be explicable by the model of Buche, i.e. the breaking of a short chain causes another to break and that so on throughout the whole sample. Case 2. Chain scission predominant condition. Ultimate elongation increases by irradiation for a certain dose. This fact can understand by the model of Buche. But from a certain dose ultimate elongation does not increase. In the period the structure of the sample turned to be the same structure as the low molecular weight amorphose polymer vulcanized. Case 3. Rate of cross-linking and scission is the same. The average chain length does not chainge in the condition. But the distribution of chain length became wider and wider by irradiation. The increase of short chain result the decrease in ultimate elongation. (author)

A Herpesviral Immediate Early Protein Promotes Transcription Elongation of Viral Transcripts.

Science.gov (United States)

Fox, Hannah L; Dembowski, Jill A; DeLuca, Neal A

2017-06-13

Herpes simplex virus 1 (HSV-1) genes are transcribed by cellular RNA polymerase II (RNA Pol II). While four viral immediate early proteins (ICP4, ICP0, ICP27, and ICP22) function in some capacity in viral transcription, the mechanism by which ICP22 functions remains unclear. We observed that the FACT complex (comprised of SSRP1 and Spt16) was relocalized in infected cells as a function of ICP22. ICP22 was also required for the association of FACT and the transcription elongation factors SPT5 and SPT6 with viral genomes. We further demonstrated that the FACT complex interacts with ICP22 throughout infection. We therefore hypothesized that ICP22 recruits cellular transcription elongation factors to viral genomes for efficient transcription elongation of viral genes. We reevaluated the phenotype of an ICP22 mutant virus by determining the abundance of all viral mRNAs throughout infection by transcriptome sequencing (RNA-seq). The accumulation of almost all viral mRNAs late in infection was reduced compared to the wild type, regardless of kinetic class. Using chromatin immunoprecipitation sequencing (ChIP-seq), we mapped the location of RNA Pol II on viral genes and found that RNA Pol II levels on the bodies of viral genes were reduced in the ICP22 mutant compared to wild-type virus. In contrast, the association of RNA Pol II with transcription start sites in the mutant was not reduced. Taken together, our results indicate that ICP22 plays a role in recruiting elongation factors like the FACT complex to the HSV-1 genome to allow for efficient viral transcription elongation late in viral infection and ultimately infectious virion production. IMPORTANCE HSV-1 interacts with many cellular proteins throughout productive infection. Here, we demonstrate the interaction of a viral protein, ICP22, with a subset of cellular proteins known to be involved in transcription elongation. We determined that ICP22 is required to recruit the FACT complex and other transcription

Endogenous abscisic acid as a key switch for natural variation in flooding-induced shoot elongation.

Science.gov (United States)

Chen, Xin; Pierik, Ronald; Peeters, Anton J M; Poorter, Hendrik; Visser, Eric J W; Huber, Heidrun; de Kroon, Hans; Voesenek, Laurentius A C J

2010-10-01

Elongation of leaves and stem is a key trait for survival of terrestrial plants during shallow but prolonged floods that completely submerge the shoot. However, natural floods at different locations vary strongly in duration and depth, and, therefore, populations from these locations are subjected to different selection pressure, leading to intraspecific variation. Here, we identified the signal transduction component that causes response variation in shoot elongation among two accessions of the wetland plant Rumex palustris. These accessions differed 2-fold in petiole elongation rates upon submergence, with fast elongation found in a population from a river floodplain and slow elongation in plants from a lake bank. Fast petiole elongation under water consumes carbohydrates and depends on the (inter)action of the plant hormones ethylene, abscisic acid, and gibberellic acid. We found that carbohydrate levels and dynamics in shoots did not differ between the fast and slow elongating plants, but that the level of ethylene-regulated abscisic acid in petioles, and hence gibberellic acid responsiveness of these petioles explained the difference in shoot elongation upon submergence. Since this is the exact signal transduction level that also explains the variation in flooding-induced shoot elongation among plant species (namely, R. palustris and Rumex acetosa), we suggest that natural selection results in similar modification of regulatory pathways within and between species.

Experimental results on elongation control using dynamic input allocation at FTU

International Nuclear Information System (INIS)

Varano, G.; Boncagni, L.; Galeani, S.; Granucci, G.; Vitale, V.; Zaccarian, L.

2011-01-01

We report on the experimental results related to a recently proposed control scheme for the regulation of plasma elongation using the poloidal field coils available at FTU, already used for the horizontal position control. The proposed technique allows to realize elongation regulation as a secondary task using the same poloidal coils.

Phytotoxicity of sorgoleone found in grain Sorghum root exudates.

Science.gov (United States)

Einhellig, F A; Souza, I F

1992-01-01

Root exudates ofSorghum bicolor consist primarily of a dihydroquinone that is quickly oxidized to ap-benzoquinone named sorgoleone. The aim of this investigation was to determine the potential activity of sorgoleone as an inhibitor of weed growth. Bioassays showed 125μM sorgoleone reduced radicle elongation ofEragrostis tef. In liquid culture, 50-μM sorgoleone treatments stunted the growth ofLemna minor. Over a 10-day treatment period, 10μM sorgoleone in the nutrient medium reduced the growth of all weed seedlings tested:Abutilon theophrasti, Datura stramonium, Amaranthus retroflexus, Setaria viridis, Digitaria sanguinalis, andEchinochloa crusgalli. These data show sorgoleone has biological activity at extremely low concentrations, suggesting a strong contribution toSorghum allelopathy.

Protein synthesis in geostimulated root caps

Science.gov (United States)

Feldman, L. J.

1982-01-01

A study is presented of the processes occurring in the root cap of corn which are requisite for the formation of root cap inhibitor and which can be triggered or modulated by both light and gravity. The results of this study indicate the importance of protein synthesis for light-induced gravitropic bending in roots. Root caps in which protein synthesis is prevented are unable to induce downward bending. This suggests that light acts by stimulating proteins which are necessary for the translation of the gravitropic stimulus into a growth response (downward bending). The turnover of protein with time was also examined in order to determine whether light acts by stimulating the synthesis of unique proteins required for downward growth. It is found that auxin in combination with light allows for the translation of the gravitropic stimulus into a growth response at least in part through the modification of protein synthesis. It is concluded that unique proteins are stimulated by light and are involved in promoting the downward growth in roots which are responding to gravity.

Early Arabidopsis root hair growth stimulation by pathogenic strains of Pseudomonas syringae.

Science.gov (United States)

Pecenková, Tamara; Janda, Martin; Ortmannová, Jitka; Hajná, Vladimíra; Stehlíková, Zuzana; Žárský, Viktor

2017-09-01

Selected beneficial Pseudomonas spp. strains have the ability to influence root architecture in Arabidopsis thaliana by inhibiting primary root elongation and promoting lateral root and root hair formation. A crucial role for auxin in this long-term (1week), long-distance plant-microbe interaction has been demonstrated. Arabidopsis seedlings were cultivated in vitro on vertical plates and inoculated with pathogenic strains Pseudomonas syringae pv. maculicola (Psm) and P. syringae pv. tomato DC3000 (Pst), as well as Agrobacterium tumefaciens (Atu) and Escherichia coli (Eco). Root hair lengths were measured after 24 and 48h of direct exposure to each bacterial strain. Several Arabidopsis mutants with impaired responses to pathogens, impaired ethylene perception and defects in the exocyst vesicle tethering complex that is involved in secretion were also analysed. Arabidopsis seedling roots infected with Psm or Pst responded similarly to when infected with plant growth-promoting rhizobacteria; root hair growth was stimulated and primary root growth was inhibited. Other plant- and soil-adapted bacteria induced similar root hair responses. The most compromised root hair growth stimulation response was found for the knockout mutants exo70A1 and ein2. The single immune pathways dependent on salicylic acid, jasmonic acid and PAD4 are not directly involved in root hair growth stimulation; however, in the mutual cross-talk with ethylene, they indirectly modify the extent of the stimulation of root hair growth. The Flg22 peptide does not initiate root hair stimulation as intact bacteria do, but pretreatment with Flg22 prior to Psm inoculation abolished root hair growth stimulation in an FLS2 receptor kinase-dependent manner. These early response phenomena are not associated with changes in auxin levels, as monitored with the pDR5::GUS auxin reporter. Early stimulation of root hair growth is an effect of an unidentified component of living plant pathogenic bacteria. The root

Natural Arabidopsis brx loss-of-function alleles confer root adaptation to acidic soil.

Science.gov (United States)

Gujas, Bojan; Alonso-Blanco, Carlos; Hardtke, Christian S

2012-10-23

Soil acidification is a major agricultural problem that negatively affects crop yield. Root systems counteract detrimental passive proton influx from acidic soil through increased proton pumping into the apoplast, which is presumably also required for cell elongation and stimulated by auxin. Here, we found an unexpected impact of extracellular pH on auxin activity and cell proliferation rate in the root meristem of two Arabidopsis mutants with impaired auxin perception, axr3 and brx. Surprisingly, neutral to slightly alkaline media rescued their severely reduced root (meristem) growth by stimulating auxin signaling, independent of auxin uptake. The finding that proton pumps are hyperactive in brx roots could explain this phenomenon and is consistent with more robust growth and increased fitness of brx mutants on overly acidic media or soil. Interestingly, the original brx allele was isolated from a natural stock center accession collected from acidic soil. Our discovery of a novel brx allele in accessions recently collected from another acidic sampling site demonstrates the existence of independently maintained brx loss-of-function alleles in nature and supports the notion that they are advantageous in acidic soil pH conditions, a finding that might be exploited for crop breeding. Copyright © 2012 Elsevier Ltd. All rights reserved.

Green-Lean Synergy - Root-Cause Analysis in Food Waste Prevention

Directory of Open Access Journals (Sweden)

Pegah Amani

2015-06-01

Full Text Available Purpose_The goal of this paper is to explore the possible synergetic effects between lean philosophy and green endeavors in improving resource efficiency in the food sector. To that end, it is investigated how a proper and tailor-made adaptation of the lean six sigma root cause analysis method could help in overcoming the complexities of increased resource efficiency in food production.Design/methodology/approach_The case study concerned reduction of waste at an industrial production line of a dough-based product, through the implementation of the lean six sigma tool.Findings_An achievement of a 50% reduction of waste on the studied process line was reached, thus exceeding the initial improvement goal.Research limitations/implications (if applicable_While the explicit findings on the specific root causes of waste on this actual production line are not immediately transferrable to other cases, they show that applying this method to identifying and eliminating root causes of waste for other products and processes in the food sector could not only reduce costs but also contribute to more resource-efficient and sustainable industrial food production.Practical implications (if applicable_ Political and public high interest in environmental and social sustainability associated with food waste render this an important development.Originality/value_ While the potential of linking green and lean efforts has been acknowledged, the application of the lean six sigma methodology for more sustainable food production has not yet been explored. This paper contributes to this research

Nitrate induction of root hair density is mediated by TGA1/TGA4 and CPC transcription factors in Arabidopsis thaliana.

Science.gov (United States)

Canales, Javier; Contreras-López, Orlando; Álvarez, José M; Gutiérrez, Rodrigo A

2017-10-01

Root hairs are specialized cells that are important for nutrient uptake. It is well established that nutrients such as phosphate have a great influence on root hair development in many plant species. Here we investigated the role of nitrate on root hair development at a physiological and molecular level. We showed that nitrate increases root hair density in Arabidopsis thaliana. We found that two different root hair defective mutants have significantly less nitrate than wild-type plants, suggesting that in A. thaliana root hairs have an important role in the capacity to acquire nitrate. Nitrate reductase-null mutants exhibited nitrate-dependent root hair phenotypes comparable with wild-type plants, indicating that nitrate is the signal that leads to increased formation of root hairs. We examined the role of two key regulators of root hair cell fate, CPC and WER, in response to nitrate treatments. Phenotypic analyses of these mutants showed that CPC is essential for nitrate-induced responses of root hair development. Moreover, we showed that NRT1.1 and TGA1/TGA4 are required for pathways that induce root hair development by suppression of longitudinal elongation of trichoblast cells in response to nitrate treatments. Our results prompted a model where nitrate signaling via TGA1/TGA4 directly regulates the CPC root hair cell fate specification gene to increase formation of root hairs in A. thaliana. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

Gradual nerve elongation affects nerve cell bodies and neuro-muscular junctions.

Science.gov (United States)

Kazuo Ikeda, K I; Masaki Matsuda, M M; Daisuke Yamauchi, D Y; Katsuro Tomita, K T; Shigenori Tanaka, S T

2005-07-01

The purpose of this study is to clarify the reactions of the neuro-muscular junction and nerve cell body to gradual nerve elongation. The sciatic nerves of Japanese white rabbits were lengthened by 30 mm in increments of 0.8 mm/day, 2.0 mm/day and 4.0 mm/day. A scanning electron microscopic examination showed no degenerative change at the neuro-muscular junction, even eight weeks after elongation in the 4-mm group. Hence, neuro-muscular junction is not critical for predicting damage from gradual nerve elongation. There were no axon reaction cells in the 0.8-mm group, a small amount in the 2-mm group, and a large amount in the 4-mm group. The rate of growth associated protein-43 positive nerve cells was significant in the 4-mm group. Hence, the safe speed for nerve cells appeared to be 0.8-mm/day, critical speed to be 2.0-mm/day, and dangerous speed to be 4.0-mm/day in this elongation model.

Elongational flow of polymer melts at constant strain rate, constant stress and constant force

Science.gov (United States)

Wagner, Manfred H.; Rolón-Garrido, Víctor H.

2013-04-01

Characterization of polymer melts in elongational flow is typically performed at constant elongational rate or rarely at constant tensile stress conditions. One of the disadvantages of these deformation modes is that they are hampered by the onset of "necking" instabilities according to the Considère criterion. Experiments at constant tensile force have been performed even more rarely, in spite of the fact that this deformation mode is free from necking instabilities and is of considerable industrial relevance as it is the correct analogue of steady fiber spinning. It is the objective of the present contribution to present for the first time a full experimental characterization of a long-chain branched polyethylene melt in elongational flow. Experiments were performed at constant elongation rate, constant tensile stress and constant tensile force by use of a Sentmanat Extensional Rheometer (SER) in combination with an Anton Paar MCR301 rotational rheometer. The accessible experimental window and experimental limitations are discussed. The experimental data are modelled by using the Wagner I model. Predictions of the steady-start elongational viscosity in constant strain rate and creep experiments are found to be identical, albeit only by extrapolation of the experimental data to Hencky strains of the order of 6. For constant stress experiments, a minimum in the strain rate and a corresponding maximum in the elongational viscosity is found at a Hencky strain of the order of 3, which, although larger than the steady-state value, follows roughly the general trend of the steady-state elongational viscosity. The constitutive analysis also reveals that constant tensile force experiments indicate a larger strain hardening potential than seen in constant elongation rate or constant tensile stress experiments. This may be indicative of the effect of necking under constant elongation rate or constant tensile stress conditions according to the Considère criterion.

Cladding axial elongation models for FRAP-T6

International Nuclear Information System (INIS)

Shah, V.N.; Carlson, E.R.; Berna, G.A.

1983-01-01

This paper presents a description of the cladding axial elongation models developed at the Idaho National Engineering Laboratory (INEL) for use by the FRAP-T6 computer code in analyzing the response of fuel rods during reactor transients in light water reactors (LWR). The FRAP-T6 code contains models (FRACAS-II subcode) that analyze the structural response of a fuel rod including pellet-cladding-mechanical-interaction (PCMI). Recently, four models were incorporated into FRACAS-II to calculate cladding axial deformation: (a) axial PCMI, (b) trapped fuel stack, (c) fuel relocation, and (d) effective fuel thermal expansion. Comparisons of cladding axial elongation measurements from two experiments with the corresponding FRAP-T6 calculations are presented

Segmentation of elongated structures in medical images

NARCIS (Netherlands)

Staal, Jozef Johannes

2004-01-01

The research described in this thesis concerns the automatic detection, recognition and segmentation of elongated structures in medical images. For this purpose techniques have been developed to detect subdimensional pointsets (e.g. ridges, edges) in images of arbitrary dimension. These

The role of strigolactones in photomorphogenesis of pea is limited to adventitious rooting.

Science.gov (United States)

Urquhart, Shelley; Foo, Eloise; Reid, James B

2015-03-01

The recently discovered group of plant hormones, the strigolactones, have been implicated in regulating photomorphogenesis. We examined this extensively in our strigolactone synthesis and response mutants and could find no evidence to support a major role for strigolactone signaling in classic seedling photomorphogenesis (e.g. elongation and leaf expansion) in pea (Pisum sativum), consistent with two recent independent reports in Arabidopsis. However, we did find a novel effect of strigolactones on adventitious rooting in darkness. Strigolactone-deficient mutants, Psccd8 and Psccd7, produced significantly fewer adventitious roots than comparable wild-type seedlings when grown in the dark, but not when grown in the light. This observation in dark-grown plants did not appear to be due to indirect effects of other factors (e.g. humidity) as the constitutively de-etiolated mutant, lip1, also displayed reduced rooting in the dark. This role for strigolactones did not involve the MAX2 F-Box strigolactone response pathway as Psmax2 f-box mutants did not show a reduction in adventitious rooting in the dark compared with wild-type plants. The auxin-deficient mutant bushy also reduced adventitious rooting in the dark, as did decapitation of wild-type plants. Rooting was restored by the application of indole-3-acetic acid (IAA) to decapitated plants, suggesting a role for auxin in the rooting response. However, auxin measurements showed no accumulation of IAA in the epicotyls of wild-type plants compared with the strigolactone synthesis mutant Psccd8, suggesting that changes in the gross auxin level in the epicotyl are not mediating this response to strigolactone deficiency. © 2014 Scandinavian Plant Physiology Society.

Simulation of root forms using cellular automata model

International Nuclear Information System (INIS)

Winarno, Nanang; Prima, Eka Cahya; Afifah, Ratih Mega Ayu

2016-01-01

This research aims to produce a simulation program for root forms using cellular automata model. Stephen Wolfram in his book entitled “A New Kind of Science” discusses the formation rules based on the statistical analysis. In accordance with Stephen Wolfram’s investigation, the research will develop a basic idea of computer program using Delphi 7 programming language. To best of our knowledge, there is no previous research developing a simulation describing root forms using the cellular automata model compared to the natural root form with the presence of stone addition as the disturbance. The result shows that (1) the simulation used four rules comparing results of the program towards the natural photographs and each rule had shown different root forms; (2) the stone disturbances prevent the root growth and the multiplication of root forms had been successfully modeled. Therefore, this research had added some stones, which have size of 120 cells placed randomly in the soil. Like in nature, stones cannot be penetrated by plant roots. The result showed that it is very likely to further develop the program of simulating root forms by 50 variations

Simulation of root forms using cellular automata model

Energy Technology Data Exchange (ETDEWEB)

Winarno, Nanang, E-mail: nanang-winarno@upi.edu; Prima, Eka Cahya [International Program on Science Education, Universitas Pendidikan Indonesia, Jl. Dr. Setiabudi no 229, Bandung40154 (Indonesia); Afifah, Ratih Mega Ayu [Department of Physics Education, Post Graduate School, Universitas Pendidikan Indonesia, Jl. Dr. Setiabudi no 229, Bandung40154 (Indonesia)

2016-02-08

This research aims to produce a simulation program for root forms using cellular automata model. Stephen Wolfram in his book entitled “A New Kind of Science” discusses the formation rules based on the statistical analysis. In accordance with Stephen Wolfram’s investigation, the research will develop a basic idea of computer program using Delphi 7 programming language. To best of our knowledge, there is no previous research developing a simulation describing root forms using the cellular automata model compared to the natural root form with the presence of stone addition as the disturbance. The result shows that (1) the simulation used four rules comparing results of the program towards the natural photographs and each rule had shown different root forms; (2) the stone disturbances prevent the root growth and the multiplication of root forms had been successfully modeled. Therefore, this research had added some stones, which have size of 120 cells placed randomly in the soil. Like in nature, stones cannot be penetrated by plant roots. The result showed that it is very likely to further develop the program of simulating root forms by 50 variations.

Inhibition of histone deacetylation alters Arabidopsis root growth in response to auxin via PIN1 degradation.

Science.gov (United States)

Nguyen, Hoai Nguyen; Kim, Jun Hyeok; Jeong, Chan Young; Hong, Suk-Whan; Lee, Hojoung

2013-10-01

Our results showed the histone deacetylase inhibitors (HDIs) control root development in Arabidopsis via regulation of PIN1 degradation. Epigenetic regulation plays a crucial role in the expression of many genes in response to exogenous or endogenous signals in plants as well as other organisms. One of epigenetic mechanisms is modifications of histone, such as acetylation and deacetylation, are catalyzed by histone acetyltransferase (HAT) and histone deacetylase (HDAC), respectively. The Arabidopsis HDACs, HDA6, and HDA19, were reported to function in physiological processes, including embryo development, abiotic stress response, and flowering. In this study, we demonstrated that histone deacetylase inhibitors (HDIs) inhibit primary root elongation and lateral root emergence. In response to HDIs treatment, the PIN1 protein was almost abolished in the root tip. However, the PIN1 gene did not show decreased expression in the presence of HDIs, whereas IAA genes exhibited increases in transcript levels. In contrast, we observed a stable level of gene expression of stress markers (KIN1 and COR15A) and a cell division marker (CYCB1). Taken together, these results suggest that epigenetic regulation may control auxin-mediated root development through the 26S proteasome-mediated degradation of PIN1 protein.

Radiomimetic effect of cisplatin on cucumber root development: the relationship between cell division and cell growth

Energy Technology Data Exchange (ETDEWEB)

Dubrovsky, J. G. [Division of Experimental Biology, Center for Biological Research (CIB), PO Box 128, La Paz, BCS 23000 (Mexico)

1993-07-01

Cisplatin [DDP, cis-dichlorodiammine platinum (II)], a strong cytostatic and antineoplastic agent, was tested on seedlings of cucumber Cucumis sativus L. for its general effect on root development and its particular effects on root cell division and cell growth. DDP was characterized as a radiomimetic compound since both DDP (1·3 × 10{sup -5} M) and γ-irradiation (2·5-10 kGy) drastically and irreversibly stopped development of embryonic lateral root primordia (LRPs) in the radicle by inhibiting both mitotic activity and cell growth. In 20% of the LRPs of DDP-treated roots, cells did not divide at all. Dividing cells completed no more than two cell cycles. These effects were specific because when DDP was available to the roots only at the onset of cell division, cell proliferation and cell growth were similar to that produced by constant incubation. Neither DDP nor γ-irradiation affected non-meristematic cell elongation. It was concluded that cell growth of meristematic cells is closely related to cell division. However, non-meristematic cell growth is independent of DNA damage. This suggests DDP as a tool to reveal these autonomous processes in plants development and to detect tissue compartments in mature plant embryos which contain potentially non-meristematic cells. (author)

N,N-dimethyl hexadecylamine and related amines regulate root morphogenesis via jasmonic acid signaling in Arabidopsis thaliana.

Science.gov (United States)

Raya-González, Javier; Velázquez-Becerra, Crisanto; Barrera-Ortiz, Salvador; López-Bucio, José; Valencia-Cantero, Eduardo

2017-05-01

Plant growth-promoting rhizobacteria are natural inhabitants of roots, colonize diverse monocot and dicot species, and affect several functional traits such as root architecture, adaptation to adverse environments, and protect plants from pathogens. N,N-dimethyl-hexadecylamine (C16-DMA) is a rhizobacterial amino lipid that modulates the postembryonic development of several plants, likely as part of volatile blends. In this work, we evaluated the bioactivity of C16-DMA and other related N,N-dimethyl-amines with varied length and found that inhibition of primary root growth was related to the length of the acyl chain. C16-DMA inhibited primary root growth affecting cell division and elongation, while promoting lateral root formation and root hair growth and density in Arabidopsis thaliana (Arabidopsis) wild-type (WT) seedlings. Interestingly, C16-DMA induced the expression of the jasmonic acid (JA)-responsive gene marker pLOX2:uidA, while JA-related mutants jar1, coi1-1, and myc2 affected on JA biosynthesis and perception, respectively, are compromised in C16-DMA responses. Comparison of auxin-regulated gene expression, root architectural changes in WT, and auxin-related mutants aux1-7, tir1/afb2/afb3, and arf7-1/arf19-1 to C16-DMA shows that the C16-DMA effects occur independently of auxin signaling. Together, these results reveal a novel class of aminolipids modulating root organogenesis via crosstalk with the JA signaling pathway.

Fine-mapping of qRL6.1, a major QTL for root length of rice seedlings grown under a wide range of NH4+ concentrations in hydroponic conditions

Science.gov (United States)

Tamura, Wataru; Ebitani, Takeshi; Yano, Masahiro; Sato, Tadashi; Yamaya, Tomoyuki

2010-01-01

Root system development is an important target for improving yield in cereal crops. Active root systems that can take up nutrients more efficiently are essential for enhancing grain yield. In this study, we attempted to identify quantitative trait loci (QTL) involved in root system development by measuring root length of rice seedlings grown in hydroponic culture. Reliable growth conditions for estimating the root length were first established to renew nutrient solutions daily and supply NH4+ as a single nitrogen source. Thirty-eight chromosome segment substitution lines derived from a cross between ‘Koshihikari’, a japonica variety, and ‘Kasalath’, an indica variety, were used to detect QTL for seminal root length of seedlings grown in 5 or 500 μM NH4+. Eight chromosomal regions were found to be involved in root elongation. Among them, the most effective QTL was detected on a ‘Kasalath’ segment of SL-218, which was localized to the long-arm of chromosome 6. The ‘Kasalath’ allele at this QTL, qRL6.1, greatly promoted root elongation under all NH4+ concentrations tested. The genetic effect of this QTL was confirmed by analysis of the near-isogenic line (NIL) qRL6.1. The seminal root length of the NIL was 13.5–21.1% longer than that of ‘Koshihikari’ under different NH4+ concentrations. Toward our goal of applying qRL6.1 in a molecular breeding program to enhance rice yield, a candidate genomic region of qRL6.1 was delimited within a 337 kb region in the ‘Nipponbare’ genome by means of progeny testing of F2 plants/F3 lines derived from a cross between SL-218 and ‘Koshihikari’. Electronic supplementary material The online version of this article (doi:10.1007/s00122-010-1328-3) contains supplementary material, which is available to authorized users. PMID:20390245

The influence of calcium and pH on growth in primary roots of Zea mays

Science.gov (United States)

Hasenstein, K. H.; Evans, M. L.

1988-01-01

We investigated the interaction of Ca2+ and pH on root elongation in Zea mays L. cv. B73 x Missouri 17 and cv. Merit. Seedlings were raised to contain high levels of Ca2+ (HC, imbibed and raised in 10 mM CaCl2) or low levels of Ca2+ (LC, imbibed and raised in distilled water). In HC roots, lowering the pH (5 mM MES/Tris) from 6.5 to 4.5 resulted in strong, long-lasting growth promotion. Surprisingly, increasing the pH from 6.5 to 8.5 also resulted in strong growth promotion. In LC roots acidification of the medium (pH 6.5 to 4.5) resulted in transient growth stimulation followed by a gradual decline in the growth rate toward zero. Exposure of LC roots to high pH (pH shift from 6.5 to 8.5) also promoted growth. Addition of EGTA resulted in strong growth promotion in both LC and HC roots. The ability of EGTA to stimulate growth appeared not to be related to H+ release from EGTA upon Ca2+ chelation since, 1) LC roots showed a strong and prolonged response to EGTA, but only a transient response to acid pH, and 2) promotion of growth by EGTA was observed in strongly buffered solutions. We also examined the pH dependence of the release of 45Ca2+ from roots of 3-day-old seedlings grown from grains imbibed in 45Ca2+. Release of 45Ca2+ from the root into agar blocks placed on the root surface was greater the more acidic the pH of the blocks. The results indicate that Ca2+ may be necessary for the acid growth response in roots.

Can differences in root responses to soil drying and compaction explain differences in performance of trees growing on landfill sites?

Science.gov (United States)

Liang, Jiansheng; Zhang, Jianhua; Chan, Gilbert Y. S.; Wong, M. H.

1999-07-01

Two tropical woody species, Acacia confusa Merrill and Litsea glutinosa (Lour.) C.B. Robinson, were grown under controlled conditions in PVC pipes filled with John Innes No. 2 soil. To investigate root distribution, physiological characteristics and hydraulic conductivity, four soil treatments were imposed-well-watered and noncompacted (control), well-watered and compacted; unwatered and noncompacted, and unwatered and compacted. In L. glutinosa, rooting depth and root elongation were severely restricted when soil bulk density increased from around 1.12 to 1.62 g cm(-3), whereas soil compaction had little effect on these parameters in A. confusa. As soil drying progressed, root water potential and osmotic potential declined more slowly in L. glutinosa than in A. confusa. Both the soil drying and compaction treatments significantly stimulated the accumulation of root abscisic acid (ABA) in both species. Soil drying damaged the root cell membrane of A. confusa, but had little influence on the root cell membrane of L. glutinosa. Soil drying had a greater effect on root hydraulic conductivity (L(p)) in L. glutinosa than in A. confusa, whereas the effect of soil compaction on L(p) was less in L. glutinosa than in A. confusa. Soil drying enhanced the effects of soil compaction on root L(p). We conclude that soil drying and compaction have large species-specific effects on the distribution, growth and physiology of roots. The relationships of these root properties to the species' ability to tolerate unfavorable soil conditions were examined.

Nitric oxide mediates strigolactone signaling in auxin and ethylene-sensitive lateral root formation in sunflower seedlings.

Science.gov (United States)

Bharti, Niharika; Bhatla, Satish C

2015-01-01

Strigolactones (SLs) play significant role in shaping root architecture whereby auxin-SL crosstalk has been observed in SL-mediated responses of primary root elongation, lateral root formation and adventitious root (AR) initiation. Whereas GR24 (a synthetic strigolactone) inhibits LR and AR formation, the effect of SL biosynthesis inhibitor (fluridone) is just the opposite (root proliferation). Naphthylphthalamic acid (NPA) leads to LR proliferation but completely inhibits AR development. The diffusive distribution of PIN1 in the provascular cells in the differentiating zone of the roots in response to GR24, fluridone or NPA treatments further indicates the involvement of localized auxin accumulation in LR development responses. Inhibition of LR formation by GR24 treatment coincides with inhibition of ACC synthase activity. Profuse LR development by fluridone and NPA treatments correlates with enhanced [Ca(2+)]cyt in the apical region and differentiating zones of LR, indicating a critical role of [Ca(2+)] in LR development in response to the coordinated action of auxins, ethylene and SLs. Significant enhancement of carotenoid cleavage dioxygenase (CCD) activity (enzyme responsible for SL biosynthesis) in tissue homogenates in presence of cPTIO (NO scavenger) indicates the role of endogenous NO as a negative modulator of CCD activity. Differences in the spatial distribution of NO in the primary and lateral roots further highlight the involvement of NO in SL-modulated root morphogenesis in sunflower seedlings. Present work provides new report on the negative modulation of SL biosynthesis through modulation of CCD activity by endogenous nitric oxide during SL-modulated LR development.

Experimental and mathematical methods for representing relative surface elongation of the ACL

NARCIS (Netherlands)

Pioletti, D. P.; Heegaard, J. H.; Rakotomanana, R. L.; Leyvraz, P. F.; Blankevoort, L.

1995-01-01

The common approach to assess the stabilizing role of the ACL in the knee has been to measure the elongation of a few marked fibers in the ligament. A comparison of the relative elongation (RE) of these marked fibers between different specimens and studies is delicate due to the difficulty of

Behaviour of enzymatic activities and root elongation in Argiudoll soils from the Argentine Humid Pampa treated with biosolids Comportamiento de actividades enzimáticas y elongación de raíces en suelos Argiudoles de la Pampa Húmeda, Argentina, tratados con biosólidos

Directory of Open Access Journals (Sweden)

E.B.R. Perotti

2008-06-01

Full Text Available The incorporation of biosolids to soil is a strategy aiming at the re-location of these materials in the environment with a useful end: soil fertilization. In this work, the response of two Argiudoll soils (one with more than 100 years of agriculture and the other, a virgin one to biosolid incorporation was studied under laboratory conditions. To measure this response, soil enzymatic biodescriptors, such as dehydrogenase and urease activities, and tests related to plant physiology (the root elongation test were employed. The addition of the biosolid to both soils had a stimulating effect though different on each soil according to the added dose. Adjustment of the regression line for dehydrogenase activity with root elongation was positive and statistically significant (pLa incorporación de biosólidos al suelo es una estrategia que tiene como objetivo la reubicación de estos materiales en el ambiente con un fin útil, como es la fertilización del suelo. En este trabajo se estudió, en condiciones controladas de laboratorio, la respuesta de dos suelos Argiudoles (uno con más de 100 años de agricultura y otro virgen frente a la perturbación físico-química y biótica que genera la incorporación de un biosólido. Para medir esta respuesta se emplearon dos biodescriptores edáficos (las actividades deshidrogenasa y ureasa y un tercero referido a la fisiología vegetal, la prueba de elongación de raíces. La incorporación del biosólido en ambos suelos, en general no deprimió el funcionamiento de las actividades enzimáticas estudiadas; contrariamente, según la dosis aportada tuvo un efecto estimulante, aunque diferente, entre ambos suelos. El ajuste de la recta de regresión de la actividad deshidrogenasa con la elongación de las plántulas fue positivo y altamente significativo, lo que indica la complementaridad de ambos descriptores. Los resultados obtenidos sugieren que los biodescriptores empleados resultaron aptos para estudiar el

Nine years of irrigation cause vegetation and fine root shifts in a water-limited pine forest.

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Claude Herzog

Full Text Available Scots pines (Pinus sylvestris L. in the inner-Alpine dry valleys of Switzerland have suffered from increased mortality during the past decades, which has been caused by longer and more frequent dry periods. In addition, a proceeding replacement of Scots pines by pubescent oaks (Quercus pubescens Willd. has been observed. In 2003, an irrigation experiment was performed to track changes by reducing drought pressure on the natural pine forest. After nine years of irrigation, we observed major adaptations in the vegetation and shifts in Scots pine fine root abundance and structure. Irrigation permitted new plant species to assemble and promote canopy closure with a subsequent loss of herb and moss coverage. Fine root dry weight increased under irrigation and fine roots had a tendency to elongate. Structural composition of fine roots remained unaffected by irrigation, expressing preserved proportions of cellulose, lignin and phenolic substances. A shift to a more negative δ13C signal in the fine root C indicates an increased photosynthetic activity in irrigated pine trees. Using radiocarbon (14C measurement, a reduced mean age of the fine roots in irrigated plots was revealed. The reason for this is either an increase in newly produced fine roots, supported by the increase in fine root biomass, or a reduced lifespan of fine roots which corresponds to an enhanced turnover rate. Overall, the responses belowground to irrigation are less conspicuous than the more rapid adaptations aboveground. Lagged and conservative adaptations of tree roots with decadal lifespans are challenging to detect, hence demanding for long-term surveys. Investigations concerning fine root turnover rate and degradation processes under a changing climate are crucial for a complete understanding of C cycling.

An efficient in vitro shoot regeneration from leaf petiolar explants and ex vitro rooting of Bixa orellana L.- A dye yielding plant.

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Mohammed, Arifullah; Chiruvella, Kishore K; Namsa, Nima D; Ghanta, Rama Gopal

2015-07-01

Bixa orellana L. (Bixaceae) is a multipurpose tree grown for the production of commercially important dyes. In the present study, an efficient, reproducible protocol was developed for direct plant regeneration from in vitro derived petiole explants of Bixa orellana L. Murashige and Skoog medium (MS) supplemented with 2-isopentenyl adenine (9.8 μM) and naphthalene acetic acid (10.7 μM) was found to be optimum for production of high frequency of shoot organogenesis. Subculturing of the shoots onto the fresh MS medium containing similar concentrations of 2-iP (9.8 μM) and NAA (10.7 μM) produced elongated shoots. Elongated shoots when placed onto MS medium supplemented with 1.7 μM indole-3-acetic acid and 14.7 μM 2-iP produced optimal rooting. Rooted plantlets were acclimatized and transplanted to the field successfully. Histological investigation revealed the origin of shoot primordia, from sub-epidermal cells of petiole explants. The regeneration protocol developed in this study can be useful for mass in vitro propagation and effective genetic transformation of commercially important edible dye yielding tree species.

Sound propagation in elongated superfluid fermionic clouds

International Nuclear Information System (INIS)

Capuzzi, P.; Vignolo, P.; Federici, F.; Tosi, M. P.

2006-01-01

We use hydrodynamic equations to study sound propagation in a superfluid Fermi gas at zero temperature inside a strongly elongated cigar-shaped trap, with main attention to the transition from the BCS to the unitary regime. First, we treat the role of the radial density profile in the limit of a cylindrical geometry and then evaluate numerically the effect of the axial confinement in a configuration in which a hole is present in the gas density at the center of the trap. We find that in a strongly elongated trap the speed of sound in both the BCS and the unitary regime differs by a factor √(3/5) from that in a homogeneous three-dimensional superfluid. The predictions of the theory could be tested by measurements of sound-wave propagation in a setup such as that exploited by Andrews et al. [Phys. Rev. Lett. 79, 553 (1997)] for an atomic Bose-Einstein condensate

Phytosterol content and the campesterol:sitosterol ratio influence cotton fiber development: role of phytosterols in cell elongation.

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Deng, Shasha; Wei, Ting; Tan, Kunling; Hu, Mingyu; Li, Fang; Zhai, Yunlan; Ye, Shue; Xiao, Yuehua; Hou, Lei; Pei, Yan; Luo, Ming

2016-02-01

Phytosterols play an important role in plant growth and development, including cell division, cell elongation, embryogenesis, cellulose biosynthesis, and cell wall formation. Cotton fiber, which undergoes synchronous cell elongation and a large amount of cellulose synthesis, is an ideal model for the study of plant cell elongation and cell wall biogenesis. The role of phytosterols in fiber growth was investigated by treating the fibers with tridemorph, a sterol biosynthetic inhibitor. The inhibition of phytosterol biosynthesis resulted in an apparent suppression of fiber elongation in vitro or in planta. The determination of phytosterol quantity indicated that sitosterol and campesterol were the major phytosterols in cotton fibers; moreover, higher concentrations of these phytosterols were observed during the period of rapid elongation of fibers. Furthermore, the decrease and increase in campesterol:sitosterol ratio was associated with the increase and decease in speed of elongation, respectively, during the elongation stage. The increase in the ratio was associated with the transition from cell elongation to secondary cell wall synthesis. In addition, a number of phytosterol biosynthetic genes were down-regulated in the short fibers of ligon lintless-1 mutant, compared to its near-isogenic wild-type TM-1. These results demonstrated that phytosterols play a crucial role in cotton fiber development, and particularly in fiber elongation.

Arabidopsis mutants lacking asparaginases develop normally but exhibit enhanced root inhibition by exogenous asparagine.

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Ivanov, Ana; Kameka, Alexander; Pajak, Agnieszka; Bruneau, Luanne; Beyaert, Ronald; Hernández-Sebastià, Cinta; Marsolais, Frédéric

2012-06-01

Asparaginase catalyzes the degradation of L-asparagine to L-aspartic acid and ammonia, and is implicated in the catabolism of transported asparagine in sink tissues of higher plants. The Arabidopsis genome includes two genes, ASPGA1 and ASPGB1, belonging to distinct asparaginase subfamilies. Conditions of severe nitrogen limitation resulted in a slight decrease in seed size in wild-type Arabidopsis. However, this response was not observed in a homozygous T-DNA insertion mutant where ASPG genes had been inactivated. Under nitrogen-sufficient conditions, the ASPG mutant had elevated levels of free asparagine in mature seed. This phenotype was observed exclusively under conditions of low illumination, when a low ratio of carbon to nitrogen was translocated to the seed. Mutants deficient in one or both asparaginases were more sensitive than wild-type to inhibition of primary root elongation and root hair emergence by L-asparagine as a single nitrogen source. This enhanced inhibition was associated with increased accumulation of asparagine in the root of the double aspga1-1/-b1-1 mutant. This indicates that inhibition of root growth is likely elicited by asparagine itself or an asparagine-derived metabolite, other than the products of asparaginase, aspartic acid or ammonia. During germination, a fusion between the ASPGA1 promoter and beta-glucuronidase was expressed in endosperm cells starting at the micropylar end. Expression was initially high throughout the root and hypocotyl, but became restricted to the root tip after three days, which may indicate a transition to nitrogen-heterotrophic growth.

An Actomyosin-Arf-GEF Negative Feedback Loop for Tissue Elongation under Stress.

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West, Junior J; Zulueta-Coarasa, Teresa; Maier, Janna A; Lee, Donghoon M; Bruce, Ashley E E; Fernandez-Gonzalez, Rodrigo; Harris, Tony J C

2017-08-07

In response to a pulling force, a material can elongate, hold fast, or fracture. During animal development, multi-cellular contraction of one region often stretches neighboring tissue. Such local contraction occurs by induced actomyosin activity, but molecular mechanisms are unknown for regulating the physical properties of connected tissue for elongation under stress. We show that cytohesins, and their Arf small G protein guanine nucleotide exchange activity, are required for tissues to elongate under stress during both Drosophila dorsal closure (DC) and zebrafish epiboly. In Drosophila, protein localization, laser ablation, and genetic interaction studies indicate that the cytohesin Steppke reduces tissue tension by inhibiting actomyosin activity at adherens junctions. Without Steppke, embryogenesis fails, with epidermal distortions and tears resulting from myosin misregulation. Remarkably, actomyosin network assembly is necessary and sufficient for local Steppke accumulation, where live imaging shows Steppke recruitment within minutes. This rapid negative feedback loop provides a molecular mechanism for attenuating the main tension generator of animal tissues. Such attenuation relaxes tissues and allows orderly elongation under stress. Copyright © 2017 Elsevier Ltd. All rights reserved.

Additional disinfection with a modified salt solution in a root canal model.

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van der Waal, Suzette V; Oonk, Charlotte A M; Nieman, Selma H; Wesselink, Paul R; de Soet, Johannes J; Crielaard, Wim

2015-10-01

The aim of this study is to investigate the disinfecting properties of a modified salt solution (MSS) and calcium hydroxide (Ca(OH)2) in a non-direct-contact ex-vivo model. Seventy-four single-canal roots infected with Enterococcus faecalis were treated with 1% sodium hypochlorite (NaOCl) irrigation or with NaOCl irrigation with subsequent dressing with MSS or Ca(OH)2. After removal of the dressings, the roots were filled with bacterial growth medium and incubated for seven days to enable the surviving bacteria to repopulate the root canal lumen. Growth was determined by sampling the root canals with paper points before treatment (S1), after treatment (S2) and incubation after treatment (S3). The colony forming units were counted at S1 and S2. At S3, growth was determined as no/yes regrowth. The Kruskal-Wallis, McNemar and χ(2) test were used for statistical analyses. At S2, in the NaOCl group, growth was found in 5 of 19 root canals. After the removal of MSS or Ca(OH)2 bacteria were retrieved from one root canal in both groups. At S3, repopulation of the root canals had occurred in 14 of 19 roots after sole NaOCl irrigation, 6 of 20 roots after MSS-dressing and in 14 of 20 roots after Ca(OH)2-dressing. MSS was more effective in preventing regrowth than Ca(OH)2 (P=0.009). The modified salt solution prevented regrowth in roots which indicates that it can eliminate persistent bacteria. Dressing the root canals with Ca(OH)2 did not provide additional disinfection after NaOCl irrigation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Uronide Deposition Rates in the Primary Root of Zea mays1

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Silk, Wendy Kuhn; Walker, Robert C.; Labavitch, John

1984-01-01

The spatial distribution of the rate of deposition of uronic acids in the elongation zone of Zea mays L. Crow WF9 × Mo 17 was determined using the continuity equation with experimentally determined values for uronide density and growth velocity. In spatial terms, the uronide deposition rate has a maximum of 0.4 micrograms per millimeter per hour at s = 3.5 mm (i.e., at the location 3.5 mm from the root tip) and decreases to 0.1 mg mm−1 h−1 by s = 10 mm. In terms of a material tissue element, a tissue segment located initially from s = 2.0 to s = 2.1 mm has 0.14 μg of uronic acids and increases in both length and uronic acid content until it is 0.9 mm long and has 0.7 μg of uronide when its center is at s = 10 mm. Simulations of radioactive labeling experiments show that 15 min is the appropriate time scale for pulse determinations of deposition rate profiles in a rapidly growing corn root. PMID:16663488

Induction of Plant Curvature by Magnetophoresis and Cytoskeletal Changes during Root Graviresponse

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Hasenstein, Karl H.; Kuznetsov, Oleg A.; Blancaflor, Eilson B.

1996-01-01

High gradient magnetic fields (HGMF) induce curvature in roots and shoots. It is considered that this response is likely to be based on the intracellular displacement of bulk starch (amyloplasts) by the ponderomotive force generated by the HGMF. This process is called magnetophoresis. The differential elongation during the curvature along the concave and convex flanks of growing organs may be linked to the microtubular and/or microfilament cytoskeleton. The possible existence of an effect of the HGMF on the cytoskeleton was tested for, but none was found. The application of cytoskeletal stabilizers or depolymerizers showed that neither microtubules, nor microfilaments, are involved in the graviresponse.

Active feedback stabilization of axisymmetric modes in highly elongated tokamak plasmas

International Nuclear Information System (INIS)

Ward, D.J.; Hofmann, F.

1993-07-01

Active feedback stabilization of the vertical instability is studied for highly elongated tokamak plasmas (1≤κ≤3), and evaluated in particular for the TCV configuration. It is shown that the feedback can strongly affect the form of the eigenfunction for these highly elongated equilibria, and this can have detrimental effects on the ability of the feedback system to properly detect and stabilize the plasma. A calculation of the vertical displacement that uses poloidal flux measurements, poloidal magnetic field measurements, and corrections for the vessel eddy currents and active feedback currents was found to be effective even in the cases with the worst deformations of the eigenfunction. We also examine how these deformations affect differently shaped equilibria, and it is seen that the magnitude of the deformation of the eigenfunction is strongly function of the plasma elongation. (author) 15 figs., 13 refs

Overexpression of rice LRK1 restricts internode elongation by down-regulating OsKO2.

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Yang, Mengfei; Qi, Weiwei; Sun, Fan; Zha, Xiaojun; Chen, Mingluan; Huang, Yunqing; Feng, Yu-Qi; Yang, Jinshui; Luo, Xiaojin

2013-01-01

Rice (Oryza sativa) has the potential to undergo rapid internodal elongation which determines plant height. Gibberellin is involved in internode elongation. Leucine-rich repeat receptor-like kinases (LRR-RLKs) are the largest subfamily of transmembrane receptor-like kinases in plants. LRR-RLKs play important functions in mediating a variety of cellular processes and regulating responses to environmental signals. LRK1, a PSK receptor homolog, is a member of the LRR-RLK family. In the present study, differences in ectopic expression of LRK1 were consistent with extent of rice internode elongation. Analyses of gene expression demonstrated that LRK1 restricts gibberellin biosynthesis during the internode elongation process by down-regulation of the gibberellin biosynthetic gene coding for ent-kaurene oxidase.

Tree-root control of shallow landslides

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Cohen, Denis; Schwarz, Massimiliano

2017-08-01

in tension can prevent failure by reducing soil compressive forces downslope. When root reinforcement is limited, a crack parallel to the slope forms near the top of the hillslope. Simulations with roots that fail across this crack always resulted in a landslide. Slopes that did not form a crack could either fail or remain stable, depending on root reinforcement. Tree spacing is important for the location of weak zones but tree location on the slope (with respect to where a crack opens) is as important. Finally, for the specific cases tested here, intermediate-sized roots (5 to 20 mm in diameter) appear to contribute most to root reinforcement. Our results show more complex behaviors than can be obtained with the traditional slope-uniform, apparent-cohesion approach. A full understanding of the mechanisms of shallow landslide triggering requires a complete re-evaluation of this traditional approach that cannot predict where and how forces are mobilized and distributed in roots and soils, and how these control shallow landslides shape, size, location, and timing.

Effect of lanthanum on rooting of in vitro regenerated shoots of Saussurea involucrata Kar. et Kir.

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Guo, Bin; Xu, Ling-Ling; Guan, Zhen-Jun; Wei, Ya-Hui

2012-06-01

In present study, the effect of lanthanum (La) on the rooting of regenerated shoots of Saussurea involucrata Kar. et Kir was analyzed. Rooting occurred from regenerated shoots inoculated on a medium supplemented with La, the plant rooting hormone indole-3-acetic acid (IAA), or both La and IAA together. The highest rooting efficiency (96%), root number/shoot (8.5), and root length (63 mm) were recorded in shoots cultured on medium containing 2.5 μM IAA combined with 100 μM La(3+). In order to elucidate the mechanism of rooting enhancement by La, we examined dynamic changes in antioxidant enzyme activities in plant tissue over time in culture. We found that the activities of peroxidase (POX) and superoxide dismutase (SOD) were significantly higher in plant tissue cultured in IAA plus La than in La or IAA alone. At the same time, the highest H(2)O(2) content was detected in plant tissue in the presence of 2.5 μM IAA plus 100 μM La(3+). In light of these data and previous results, we speculate that La enhanced IAA-induced rooting by acting as a mild abiotic stress to stimulate POX and SOD activities in plant cells. Then, IAA reacted with oxygen and POX to form the ternary complex enzyme-IAA-O(2) that dissociated into IAA radicals and O(2)(-). Subsequently, IAA-induced O(2)(-) readily converted to hydroxyl radical (HO·) via SOD-catalyzed dismutation. Finally, cell wall loosening and cell elongation occurred as a consequence of HO-dependent scission of wall components, leading to root growth. The treatment of IAA combined with La resulted in the highest plantlet survival (80%) compared to single treatments with IAA or La alone. These data suggest that rare earth elements enhance root morphogenesis and the growth of S. involucrata.

EFFECT OF PRE-TREATMENT ON QUALITATIVE INDICES OF WHITE ROOTS

Directory of Open Access Journals (Sweden)

I. Bilenka

2018-04-01

Full Text Available In the work, various technological methods are presented of preliminary processing of celery and parsnip roots to prevent their darkening during cooking in restaurants. These methods are: immersing in a citric acid solution (c = 0.05 %, 0.1 %, 0.15 %, in solution NaCl (c = 0. 5%, 1 %, 2 %, and microwave processing in various modes. The activity of peroxidase, polyphenol oxidase, and ascorbate oxidase enzymes of root crops in the varietal section is also determined. Fresh white roots were selected as research objects: celery of the varieties Yablucnyy and Diamant, and parsnip of the varieties Student and Kruhlyy. It was revealed that polyphenol oxidase shows the highest activity. In order to inactivate the above-stated oxidoreductase, different methods of treating white roots were compared, too. The lowest oxidative enzymes activity was characteristic of the roots of the Diamant varieties and the parsnip roots of the Student variety, which were selected for further work. Studies have been carried out on changes in the mass fraction of L-ascorbic acid during steam blasting and microwave processing in different modes. It is proved that the treatment of white roots with ultra high frequency irradiation at 650 W for 1 minute is optimal. Such treatment allowes preventing the darkening of the raw material after its peeling due to the action of oxidation-reducing enzymes. It also allows preserving L-ascorbic acid by 64.6 % and 65.0 % in the roots of celery and parsnip, respectively. The distribution of polyphenol oxidase activity in the celery and parsnip root crop is analyzed. The results of the work can be used in preparation of dishes with the use of white roots in restaurants in order to improve technological techniques during processing of raw materials into finished products, improve its quality, and preserve L-ascorbic acid, as well as expand the range of culinary products based on spicy aromatic raw materials.

Contribution of Cell Elongation to the Biofilm Formation of Pseudomonas aeruginosa during Anaerobic Respiration

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Park, Yongjin; Yoon, Sang Sun

2011-01-01

Pseudomonas aeruginosa, a gram-negative bacterium of clinical importance, forms more robust biofilm during anaerobic respiration, a mode of growth presumed to occur in abnormally thickened mucus layer lining the cystic fibrosis (CF) patient airway. However, molecular basis behind this anaerobiosis-triggered robust biofilm formation is not clearly defined yet. Here, we identified a morphological change naturally accompanied by anaerobic respiration in P. aeruginosa and investigated its effect on the biofilm formation in vitro. A standard laboratory strain, PAO1 was highly elongated during anaerobic respiration compared with bacteria grown aerobically. Microscopic analysis demonstrated that cell elongation likely occurred as a consequence of defective cell division. Cell elongation was dependent on the presence of nitrite reductase (NIR) that reduces nitrite (NO2 −) to nitric oxide (NO) and was repressed in PAO1 in the presence of carboxy-PTIO, a NO antagonist, demonstrating that cell elongation involves a process to respond to NO, a spontaneous byproduct of the anaerobic respiration. Importantly, the non-elongated NIR-deficient mutant failed to form biofilm, while a mutant of nitrate reductase (NAR) and wild type PAO1, both of which were highly elongated, formed robust biofilm. Taken together, our data reveal a role of previously undescribed cell biological event in P. aeruginosa biofilm formation and suggest NIR as a key player involved in such process. PMID:21267455

Significant enhancement by biochar of caproate production via chain elongation.

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Liu, Yuhao; He, Pinjing; Shao, Liming; Zhang, Hua; Lü, Fan

2017-08-01

In this study, biochar was introduced into a chain elongation system to enhance the bioproduction of caproate and caprylate. The concentration of caproate increased to 21.1 g/L upon the addition of biochar, which is the highest level of caproate reported for such a system to date when ethanol was used as electron donor. The addition of biochar created a tougher system with more stable microorganism community structure for chain elongation, in which no obvious inhibition by products or substrates was observed, moreover, the lag phase was reduced 2.3-fold compared to the system without biochar. These reinforcement effect of biochar are attributed to the enhanced conductivity due to the significant enrichment of functional microorganisms via the microbial network surrounding smaller biochar particles, and via the adsorption on the rough surfaces or pores of larger particles, which facilitated electron transfer. Higher amounts of extracellular polymer substances and higher conductivity induced by biochar could contribute to the reinforcement effect in chain elongation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Method for disposing of hazardous wastes

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Burton, Frederick G.; Cataldo, Dominic A.; Cline, John F.; Skiens, W. Eugene

1995-01-01

A method and system for long-term control of root growth without killing the plants bearing those roots involves incorporating a 2,6-dinitroaniline in a polymer and disposing the polymer in an area in which root control is desired. This results in controlled release of the substituted aniline herbicide over a period of many years. Herbicides of this class have the property of preventing root elongation without translocating into other parts of the plant. The herbicide may be encapsulated in the polymer or mixed with it. The polymer-herbicide mixture may be formed into pellets, sheets, pipe gaskets, pipes for carrying water, or various other forms. The invention may be applied to other protection of buried hazardous wastes, protection of underground pipes, prevention of root intrusion beneath slabs, the dwarfing of trees or shrubs and other applications. The preferred herbicide is 4-difluoromethyl-N,N-dipropyl- 2,6-dinitro-aniline, commonly known as trifluralin.

pix-1 controls early elongation in parallel with mel-11 and let-502 in Caenorhabditis elegans.

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Martin, Emmanuel; Harel, Sharon; Nkengfac, Bernard; Hamiche, Karim; Neault, Mathieu; Jenna, Sarah

2014-01-01

Cell shape changes are crucial for metazoan development. During Caenorhabditis elegans embryogenesis, epidermal cell shape changes transform ovoid embryos into vermiform larvae. This process is divided into two phases: early and late elongation. Early elongation involves the contraction of filamentous actin bundles by phosphorylated non-muscle myosin in a subset of epidermal (hypodermal) cells. The genes controlling early elongation are associated with two parallel pathways. The first one involves the rho-1/RHOA-specific effector let-502/Rho-kinase and mel-11/myosin phosphatase regulatory subunit. The second pathway involves the CDC42/RAC-specific effector pak-1. Late elongation is driven by mechanotransduction in ventral and dorsal hypodermal cells in response to body-wall muscle contractions, and involves the CDC42/RAC-specific Guanine-nucleotide Exchange Factor (GEF) pix-1, the GTPase ced-10/RAC and pak-1. In this study, pix-1 is shown to control early elongation in parallel with let-502/mel-11, as previously shown for pak-1. We show that pix-1, pak-1 and let-502 control the rate of elongation, and the antero-posterior morphology of the embryos. In particular, pix-1 and pak-1 are shown to control head, but not tail width, while let-502 controls both head and tail width. This suggests that let-502 function is required throughout the antero-posterior axis of the embryo during early elongation, while pix-1/pak-1 function may be mostly required in the anterior part of the embryo. Supporting this hypothesis we show that low pix-1 expression level in the dorsal-posterior hypodermal cells is required to ensure high elongation rate during early elongation.

Interplay between DNA supercoiling and transcription elongation.

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Ma, Jie; Wang, Michelle

2014-01-01

Transcription-coupled DNA supercoiling has been shown to be an important regulator of transcription that is broadly present in the cell. Here we review experimental work which shows that RNA polymerase is a powerful torsional motor that can alter DNA topology and structure, and DNA supercoiling in turn directly affects transcription elongation.

Transcription elongation. Heterogeneous tracking of RNA polymerase and its biological implications.

Science.gov (United States)

Imashimizu, Masahiko; Shimamoto, Nobuo; Oshima, Taku; Kashlev, Mikhail

2014-01-01

Regulation of transcription elongation via pausing of RNA polymerase has multiple physiological roles. The pausing mechanism depends on the sequence heterogeneity of the DNA being transcribed, as well as on certain interactions of polymerase with specific DNA sequences. In order to describe the mechanism of regulation, we introduce the concept of heterogeneity into the previously proposed alternative models of elongation, power stroke and Brownian ratchet. We also discuss molecular origins and physiological significances of the heterogeneity.

A Herpesviral Immediate Early Protein Promotes Transcription Elongation of Viral Transcripts

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Hannah L. Fox

2017-06-01

Full Text Available Herpes simplex virus 1 (HSV-1 genes are transcribed by cellular RNA polymerase II (RNA Pol II. While four viral immediate early proteins (ICP4, ICP0, ICP27, and ICP22 function in some capacity in viral transcription, the mechanism by which ICP22 functions remains unclear. We observed that the FACT complex (comprised of SSRP1 and Spt16 was relocalized in infected cells as a function of ICP22. ICP22 was also required for the association of FACT and the transcription elongation factors SPT5 and SPT6 with viral genomes. We further demonstrated that the FACT complex interacts with ICP22 throughout infection. We therefore hypothesized that ICP22 recruits cellular transcription elongation factors to viral genomes for efficient transcription elongation of viral genes. We reevaluated the phenotype of an ICP22 mutant virus by determining the abundance of all viral mRNAs throughout infection by transcriptome sequencing (RNA-seq. The accumulation of almost all viral mRNAs late in infection was reduced compared to the wild type, regardless of kinetic class. Using chromatin immunoprecipitation sequencing (ChIP-seq, we mapped the location of RNA Pol II on viral genes and found that RNA Pol II levels on the bodies of viral genes were reduced in the ICP22 mutant compared to wild-type virus. In contrast, the association of RNA Pol II with transcription start sites in the mutant was not reduced. Taken together, our results indicate that ICP22 plays a role in recruiting elongation factors like the FACT complex to the HSV-1 genome to allow for efficient viral transcription elongation late in viral infection and ultimately infectious virion production.

Arabidopsis homolog of trithorax1 (ATX1) is required for cell production, patterning, and morphogenesis in root development.

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Napsucialy-Mendivil, Selene; Alvarez-Venegas, Raúl; Shishkova, Svetlana; Dubrovsky, Joseph G

2014-12-01

Arabidopsis homolog of trithorax1 (ATX1/SDG27), a known regulator of flower development, encodes a H3K4histone methyltransferase that maintains a number of genes in an active state. In this study, the role of ATX1 in root development was evaluated. The loss-of-function mutant atx1-1 was impaired in primary root growth. The data suggest that ATX1 controls root growth by regulating cell cycle duration, cell production, and the transition from cell proliferation in the root apical meristem (RAM) to cell elongation. In atx1-1, the quiescent centre (QC) cells were irregular in shape and more expanded than those of the wild type. This feature, together with the atypical distribution of T-divisions, the presence of oblique divisions, and the abnormal cell patterning in the RAM, suggests a lack of coordination between cell division and cell growth in the mutant. The expression domain of QC-specific markers was expanded both in the primary RAM and in the developing lateral root primordia of atx1-1 plants. These abnormalities were independent of auxin-response gradients. ATX1 was also found to be required for lateral root initiation, morphogenesis, and emergence. The time from lateral root initiation to emergence was significantly extended in the atx1-1 mutant. Overall, these data suggest that ATX1 is involved in the timing of root development, stem cell niche maintenance, and cell patterning during primary and lateral root development. Thus, ATX1 emerges as an important player in root system architecture. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Genetic analysis of gravity signal transduction in roots

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Masson, Patrick; Strohm, Allison; Baldwin, Katherine

To grow downward into the soil, roots use gravity as a guide. Specialized cells, named stato-cytes, enable this directional growth response by perceiving gravity. Located in the columella region of the cap, these cells sense a reorientation of the root within the gravity field through the sedimentation of, and/or tension/pressure exerted by, dense amyloplasts. This process trig-gers a gravity signal transduction pathway that leads to a fast alkalinization of the cytoplasm and a change in the distribution of the plasma membrane-associated auxin-efflux carrier PIN3. The latter protein is uniformly distributed within the plasma membrane on all sides of the cell in vertically oriented roots. However, it quickly accumulates at the bottom side upon gravis-timulation. This process correlates with a preferential transport of auxin to the bottom side of the root cap, resulting in a lateral gradient across the tip. This gradient is then transported to the elongation zone where it promotes differential cellular elongation, resulting in downward curvature. We isolated mutations that affect gravity signal transduction at a step that pre-cedes cytoplasmic alkalinization and/or PIN3 relocalization and lateral auxin transport across the cap. arg1 and arl2 mutations identify a common genetic pathway that is needed for all three gravity-induced processes in the cap statocytes, indicating these genes function early in the pathway. On the other hand, adk1 affects gravity-induced PIN3 relocalization and lateral auxin transport, but it does not interfere with cytoplasmic alkalinization. ARG1 and ARL2 encode J-domain proteins that are associated with membranes of the vesicular trafficking path-way whereas ADK1 encodes adenosine kinase, an enzyme that converts adenosine derived from nucleic acid metabolism and the AdoMet cycle into AMP, thereby alleviating feedback inhibi-tion of this important methyl-donor cycle. Because mutations in ARG1 (and ARL2) do not completely eliminate

The effect of heat and radiation on the initiation and elongation processes of DNA synthesis

International Nuclear Information System (INIS)

Davies, R.C.; Bowden, G.T.; Cress, A.E.

1983-01-01

The pH step alkaline elution and alkaline sucrose gradient techniques were utilized to evaluate alterations in DNA replication (initiation and elongation) induced by heat and low dose X-irradiation in synchronized Chinese hamster ovary cells. The initiation and elongation processes of DNA synthesis were radioresistant at the G 1 /S boundary (4 hours after mitosis) while in mid S phase (9 hours after mitosis) DNA initiation and elongation were sensitive to X-irradiation. The initiation and elongation processes of DNA synthesis which were radiation resistant at the G 1 /S boundary could be inhibited by a hyperthermia treatment (43 0 C for 1 hour beginning at 4 hours after mitosis). The impairment of initiation in the heated cells was maintained through late S phase while that of elongation was reversible as judged by full recovery at 15 hours after mitosis. These data suggest that the known synergistic lethality of heat and radiation may be mediated by an impairment of initiation of DNA synthesis. (author)

Codon usage regulates protein structure and function by affecting translation elongation speed in Drosophila cells.

Science.gov (United States)

Zhao, Fangzhou; Yu, Chien-Hung; Liu, Yi

2017-08-21

Codon usage biases are found in all eukaryotic and prokaryotic genomes and have been proposed to regulate different aspects of translation process. Codon optimality has been shown to regulate translation elongation speed in fungal systems, but its effect on translation elongation speed in animal systems is not clear. In this study, we used a Drosophila cell-free translation system to directly compare the velocity of mRNA translation elongation. Our results demonstrate that optimal synonymous codons speed up translation elongation while non-optimal codons slow down translation. In addition, codon usage regulates ribosome movement and stalling on mRNA during translation. Finally, we show that codon usage affects protein structure and function in vitro and in Drosophila cells. Together, these results suggest that the effect of codon usage on translation elongation speed is a conserved mechanism from fungi to animals that can affect protein folding in eukaryotic organisms. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Restricted cell elongation in Arabidopsis hypocotyls is associated with a reduced average pectin esterification level.

Science.gov (United States)

Derbyshire, Paul; McCann, Maureen C; Roberts, Keith

2007-06-17

Cell elongation is mainly limited by the extensibility of the cell wall. Dicotyledonous primary (growing) cell walls contain cellulose, xyloglucan, pectin and proteins, but little is known about how each polymer class contributes to the cell wall mechanical properties that control extensibility. We present evidence that the degree of pectin methyl-esterification (DE%) limits cell growth, and that a minimum level of about 60% DE is required for normal cell elongation in Arabidopsis hypocotyls. When the average DE% falls below this level, as in two gibberellic acid (GA) mutants ga1-3 and gai, and plants expressing pectin methyl-esterase (PME1) from Aspergillus aculeatus, then hypocotyl elongation is reduced. Low average levels of pectin DE% are associated with reduced cell elongation, implicating PMEs, the enzymes that regulate DE%, in the cell elongation process and in responses to GA. At high average DE% other components of the cell wall limit GA-induced growth.

Restricted cell elongation in Arabidopsis hypocotyls is associated with a reduced average pectin esterification level

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Derbyshire Paul

2007-06-01

Full Text Available Abstract Background Cell elongation is mainly limited by the extensibility of the cell wall. Dicotyledonous primary (growing cell walls contain cellulose, xyloglucan, pectin and proteins, but little is known about how each polymer class contributes to the cell wall mechanical properties that control extensibility. Results We present evidence that the degree of pectin methyl-esterification (DE% limits cell growth, and that a minimum level of about 60% DE is required for normal cell elongation in Arabidopsis hypocotyls. When the average DE% falls below this level, as in two gibberellic acid (GA mutants ga1-3 and gai, and plants expressing pectin methyl-esterase (PME1 from Aspergillus aculeatus, then hypocotyl elongation is reduced. Conclusion Low average levels of pectin DE% are associated with reduced cell elongation, implicating PMEs, the enzymes that regulate DE%, in the cell elongation process and in responses to GA. At high average DE% other components of the cell wall limit GA-induced growth.

Identifying organizational deficiencies through root-cause analysis

International Nuclear Information System (INIS)

Tuli, R.W.; Apostolakis, G.E.

1996-01-01

All nuclear power plants incorporate root-cause analysis as an instrument to help identify and isolate key factors judged to be of significance following an incident or accident. Identifying the principal deficiencies can become very difficult when the event involves not only human and machine interaction, but possibly the underlying safety and quality culture of the organization. The current state of root-cause analysis is to conclude the investigation after identifying human and/or hardware failures. In this work, root-cause analysis is taken one step further by examining plant work processes and organizational factors. This extension is considered significant to the success of the analysis, especially when management deficiency is believed to contribute to the incident. The results of root-cause analysis can be most effectively implemented if the organization, as a whole, wishes to improve the overall operation of the plant by preventing similar incidents from occurring again. The study adds to the existing root-cause analysis the ability to localize the causes of undesirable events and to focus on those problems hidden deeply within the work processes that are routinely followed in the operation and maintenance of the facility

Tree-root control of shallow landslides

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D. Cohen

2017-08-01

-parallel directions. Roots in tension can prevent failure by reducing soil compressive forces downslope. When root reinforcement is limited, a crack parallel to the slope forms near the top of the hillslope. Simulations with roots that fail across this crack always resulted in a landslide. Slopes that did not form a crack could either fail or remain stable, depending on root reinforcement. Tree spacing is important for the location of weak zones but tree location on the slope (with respect to where a crack opens is as important. Finally, for the specific cases tested here, intermediate-sized roots (5 to 20 mm in diameter appear to contribute most to root reinforcement. Our results show more complex behaviors than can be obtained with the traditional slope-uniform, apparent-cohesion approach. A full understanding of the mechanisms of shallow landslide triggering requires a complete re-evaluation of this traditional approach that cannot predict where and how forces are mobilized and distributed in roots and soils, and how these control shallow landslides shape, size, location, and timing.

Stereotypical reaching movements of the octopus involve both bend propagation and arm elongation.

Science.gov (United States)

Hanassy, S; Botvinnik, A; Flash, T; Hochner, B

2015-05-13

The bend propagation involved in the stereotypical reaching movement of the octopus arm has been extensively studied. While these studies have analyzed the kinematics of bend propagation along the arm during its extension, possible length changes have been ignored. Here, the elongation profiles of the reaching movements of Octopus vulgaris were assessed using three-dimensional reconstructions. The analysis revealed that, in addition to bend propagation, arm extension movements involve elongation of the proximal part of the arm, i.e., the section from the base of the arm to the propagating bend. The elongations are quite substantial and highly variable, ranging from an average strain along the arm of -0.12 (i.e. shortening) up to 1.8 at the end of the movement (0.57 ± 0.41, n = 64 movements, four animals). Less variability was discovered in an additional set of experiments on reaching movements (0.64 ± 0.28, n = 30 movements, two animals), where target and octopus positions were kept more stationary. Visual observation and subsequent kinematic analysis suggest that the reaching movements can be broadly segregated into two groups. The first group involves bend propagation beginning at the base of the arm and propagating towards the arm tip. In the second, the bend is formed or present more distally and reaching is achieved mainly by elongation and straightening of the segment proximal to the bend. Only in the second type of movements is elongation significantly positively correlated with the distance of the bend from the target. We suggest that reaching towards a target is generated by a combination of both propagation of a bend along the arm and arm elongation. These two motor primitives may be combined to create a broad spectrum of reaching movements. The dynamical model, which recapitulates the biomechanics of the octopus muscular hydrostatic arm, suggests that achieving the observed elongation requires an extremely low ratio of longitudinal to transverse muscle

In vitro assessment of 3 dentifrices containing fluoride in preventing demineralization of overdenture abutments and root surfaces.

Science.gov (United States)

Goettsche, Zachary S; Ettinger, Ronald L; Wefel, James S; Hogan, Mary M; Harless, Jeffery D; Qian, Fang

2014-11-01

Caries development under overdentures has been a continuing problem and requires the daily use of fluoride to prevent demineralization. The purpose of this in vitro study was to compare the effectiveness of dentifrices containing tricalcium phosphate or calcium phosphosilicate in combination with fluoride to prevent the demineralization of overdenture abutments and root surfaces. A total of 56 caries-free extracted teeth were prepared as overdenture abutments. The teeth were painted with acid-resistant varnish, leaving one 1×4-mm window on occlusal and root surfaces. The teeth were randomly divided into 4 groups: a control group treated with distilled/deionized water only, a group treated with ClinPro 5000, a group treated with ReNew, and a group treated with Prevident 5000 gel. Each tooth was subjected to a demineralizing/remineralizing cycling protocol for 12 days with the appropriate treatment products. The teeth were sectioned longitudinally through both windows. Photomicrographs were made of 3 representative sections from each tooth. A representative section was defined as one that included both windows and was cut from the part of the tooth that had the flattest surface to reduce the edge effect. The depths of the lesions were measured on representative sections from each group. A 1-way MANOVA and a 1-way ANOVA with the post hoc Tukey-Kramer test were used to evaluate the treatment effects on the criterion variables (α=.05). The total lesion depths of the control teeth on the occlusal surface were not statistically significantly deeper than for the 3 dentifrices (P=.7705). However, all 3 dentifrices had narrower cavitation depths than the control (mean cavitation band depth, 43.59 [ReNew] versus 37.99 [Prevident 5000 gel] versus 36.70 [ClinPro 5000] versus 246.86 [control]) (Pteeth treated with Prevident 5000 gel had the shallowest total lesion depth and were statistically significantly different from those treated with ReNew and Clin

A morphospace for reef fishes: elongation is the dominant axis of body shape evolution.

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Thomas Claverie

Full Text Available Tropical reef fishes are widely regarded as being perhaps the most morphologically diverse vertebrate assemblage on earth, yet much remains to be discovered about the scope and patterns of this diversity. We created a morphospace of 2,939 species spanning 56 families of tropical Indo-Pacific reef fishes and established the primary axes of body shape variation, the phylogenetic consistency of these patterns, and whether dominant patterns of shape change can be accomplished by diverse underlying changes. Principal component analysis showed a major axis of shape variation that contrasts deep-bodied species with slender, elongate forms. Furthermore, using custom methods to compare the elongation vector (axis that maximizes elongation deformation and the main vector of shape variation (first principal component for each family in the morphospace, we showed that two thirds of the families diversify along an axis of body elongation. Finally, a comparative analysis using a principal coordinate analysis based on the angles among first principal component vectors of each family shape showed that families accomplish changes in elongation with a wide range of underlying modifications. Some groups such as Pomacentridae and Lethrinidae undergo decreases in body depth with proportional increases in all body regions, while other families show disproportionate changes in the length of the head (e.g., Labridae, the trunk or caudal region in all combinations (e.g., Pempheridae and Pinguipedidae. In conclusion, we found that evolutionary changes in body shape along an axis of elongation dominates diversification in reef fishes. Changes in shape on this axis are thought to have immediate implications for swimming performance, defense from gape limited predators, suction feeding performance and access to some highly specialized habitats. The morphological modifications that underlie changes in elongation are highly diverse, suggesting a role for a range of

A Morphospace for Reef Fishes: Elongation Is the Dominant Axis of Body Shape Evolution

Science.gov (United States)

Claverie, Thomas; Wainwright, Peter C.

2014-01-01

Tropical reef fishes are widely regarded as being perhaps the most morphologically diverse vertebrate assemblage on earth, yet much remains to be discovered about the scope and patterns of this diversity. We created a morphospace of 2,939 species spanning 56 families of tropical Indo-Pacific reef fishes and established the primary axes of body shape variation, the phylogenetic consistency of these patterns, and whether dominant patterns of shape change can be accomplished by diverse underlying changes. Principal component analysis showed a major axis of shape variation that contrasts deep-bodied species with slender, elongate forms. Furthermore, using custom methods to compare the elongation vector (axis that maximizes elongation deformation) and the main vector of shape variation (first principal component) for each family in the morphospace, we showed that two thirds of the families diversify along an axis of body elongation. Finally, a comparative analysis using a principal coordinate analysis based on the angles among first principal component vectors of each family shape showed that families accomplish changes in elongation with a wide range of underlying modifications. Some groups such as Pomacentridae and Lethrinidae undergo decreases in body depth with proportional increases in all body regions, while other families show disproportionate changes in the length of the head (e.g., Labridae), the trunk or caudal region in all combinations (e.g., Pempheridae and Pinguipedidae). In conclusion, we found that evolutionary changes in body shape along an axis of elongation dominates diversification in reef fishes. Changes in shape on this axis are thought to have immediate implications for swimming performance, defense from gape limited predators, suction feeding performance and access to some highly specialized habitats. The morphological modifications that underlie changes in elongation are highly diverse, suggesting a role for a range of developmental processes

Root Resorption with Orthodontic Mechanics: Pertinent Areas Revisited.

Science.gov (United States)

Krishnan, V

2017-03-01

Root resorption can occur at any time during orthodontic treatment and lead to a compromise in the prognosis of the tooth and the stability of the treatment results. Recent research has focused more on the cause and effect relationship as well as preventive or treatment options to combat this unwelcome event. Investigations have highlighted the genetic as well as molecular aspects of the process and enabled clinicians to determine which patients might be susceptible. A proper medical history, an assessment of predisposing factors, a radiographic evaluation for alterations in root morphology and careful planning and execution of orthodontic mechanics may reduce the incidence of root resorption. The current review is aimed at providing clinicians and academics with an insight into the process of root resorption, the methods of identification during its early stages and intervention at the right time to reduce its severity. © 2017 Australian Dental Association.

Co-ordinated growth between aerial and root systems in young apple plants issued from in vitro culture.

Science.gov (United States)

Costes, E; García-Villanueva, E; Jourdan, C; Regnard, J L; Guédon, Y

2006-01-01

In several species exhibiting a rhythmic aerial growth, the existence of an alternation between root and shoot growth has been demonstrated. The present study aims to investigate the respective involvement of the emergence of new organs and their elongation in relation to this phenomenon and its possible genotypic variation in young apple plants. Two apple varieties, X6407 (recently named 'Ariane') and X3305 ('Chantecler' x 'Baujade'), were compared. Five plants per variety, issued from in vitro culture, were observed in minirhizotrons over 4 months. For each plant, root emergence and growth were observed twice per week. Growth rates were calculated for all roots with more than two segments and the branching density was calculated on primary roots. On the aerial part, the number of leaves, leaf area and total shoot length were observed weekly. No significant difference was observed between varieties in any of the final characteristics of aerial growth. Increase in leaf area and shoot length exhibited a 3-week rhythm in X3305 while a weaker signal was observed in Ariane. The primary root growth rate was homogeneous between the plants and likewise between the varieties, while their branching density differed significantly. Secondary roots emerged rhythmically, with a 3-week and a 2-week rhythm, respectively, in X3305 and 'Ariane'. Despite a high intra-variety variability, significant differences were observed between varieties in the secondary root life span and mean length. A synchronism between leaf emergence and primary root growth was highlighted in both varieties, while an opposition phase was observed between leaf area increments and secondary root emergence in X3305 only. A biological model of dynamics that summarizes the interactions between processes and includes the assumption of a feedback effect of lateral root emergence on leaf emergence is proposed.

Root characteristics of cover crops and their erosion-reducing potential during concentrated runoff

Science.gov (United States)

de Baets, S.; Poesen, J.

2009-04-01

In the loam region in central Belgium, a lot of research has been conducted on the effects of cover crops for preventing splash and interrill erosion and on their nutrient pumping effectiveness. As this is a very effective erosion and environment conservation technique, planting cover crops during the winter season is widely applied in the loess belt. Most of these cover crops freeze at the beginning of the winter period. Consequently, the above-ground biomass becomes less effective in protecting the soil from water erosion. Apart from the effects of the above-ground biomass in protecting the soil against raindrop impacts and reducing flow velocities by the retarding effects of their stems, plant roots also play an important role in improving soil strength. Previous research showed that roots contribute to a large extent to the resistance of topsoils against concentrated flow erosion. Unfortunately, information on root properties of common cover crops (e.g. Sinapis alba, Phacelia tanacetifoli, Lolium perenne, Avena sativa, Secale cereale, Raphanus sativus subsp. oleiferus) is very scarce. Therefore, root density distribution with depth and their erosion-reducing effects during concentrated flow erosion were assessed by conducting root auger measurements and concentrated flow experiments at the end of the growth period (December). The preliminary results indicate that the studied cover crops are not equally effective in preventing soil loss by concentrated flow erosion at the end of the growing season. Cover crops with thick roots, such as Sinapis alba and Raphanus sativus subsp. oleiferus are less effective than cover crops with fine-branched roots such as Phacelia tanacetifoli, Lolium perenne (Ryegrass), Avena sativa (Oats) and Secale cereale (Rye) in preventing soil losses by concentrated flow erosion. These results enable soil managers to select the most suitable crops and maximize soil protection.

Multidisciplinary Management of Complicated Crown-Root Fracture of an Anterior Tooth Undergoing Apexification

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Merve Mese

2015-01-01

Full Text Available The purpose of this case report was to present the multidisciplinary management of a subgingival crown-root fracture of a patient undergoing apexification treatment. A 12-year-old male patient was referred to the pediatric dentistry clinic with an extensive tooth fracture of the right permanent maxillary lateral incisor. Clinical and radiographic examinations revealed the presence of a complicated crown-root fracture, which had elongated to the buccal subgingival area. The dental history disclosed that the apexification procedure had been started to be performed after his first trauma experience and he had neglected his appointment. The coronal fragment was gently extracted; endodontic treatment was performed; flap surgery was performed to make the fracture line visible. The coronal fragment was reattached to the root fragment with a dual-cure luting composite. A fiber post was stabilized and the access cavity of the tooth was restored with composite resin. At the end of the 24th month, the tooth was asymptomatic, functionally, esthetically acceptable and had no periapical pathology. It is important for the patients undergoing apexification treatment to keep their appointments because of the fracture risk. Restoration of the fractured tooth by preparing retention grooves and a bonding fiber-reinforced post are effective and necessary approaches for successful management.

Reaction of mycorrhizal and non-mycorrhizal Scots pine fine roots along a deposition gradient of air pollutants in eastern Germany

International Nuclear Information System (INIS)

Muenzenberger, B.; Schminke, B.; Strubelt, F.; Huettl, R.F.

1995-01-01

Based on an ecosystematic approach within the comprehensive SANA (regeneration of the atmosphere above the new federal states) project the influence of industrial air pollutants (SO 2 , NO x ) (alkaline fly ashes) on the vitality of mycorrhizal, mycorrhizal frequency, and on parameters of root growth such as root biomass and necromass and distribution of different root classes in the soil horizons was investigated. The studies were conducted in three comparable Scots pine ecosystems in eastern Germany which were exposed to different deposition loads of air pollutants during the time of the former German Democratic Republic. Site specific differences were obtained for all parameters investigated. The reference plot Neuglobsow (background deposition) revealed the highest number of vital mycorrhizal, highest mycorrhizal frequency, and largest biomass of finest roots in the humus layer. At the impact-site Roesa and Taura (heavy and moderate deposition) located near Halle/Bitterfeld and Leipzig, the number of vital mycorrhizae was reduced and the life-span of mycorrhizae of reduced vitality was elongated. Finest root biomass and necromass of the humus layer were also lower at these plots as compared to Neuglobsow. At Neuglobsow a higher turnover of mycorrhizae and finest roots of the humus layer is assumed. The reduced growth of mycorrhizal and non-mycorrhizal finest roots at the two pollution impacted sites Roesa and Taura is seen as an adaptation mechanism of the root system to high nutrient inputs. 14 refs., 4 figs

Root-Cause Analysis of a Potentially Sentinel Transfusion Event: Lessons for Improvement of Patient Safety

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Ali Reza Jeddian

2012-09-01

Full Text Available Errors prevention and patient safety in transfusion medicine are a serious concern. Errors can occur at any step in transfusion and evaluation of their root causes can be helpful for preventive measures. Root cause analysis as a structured and systematic approach can be used for identification of underlying causes of adverse events. To specify system vulnerabilities and illustrate the potential of such an approach, we describe the root cause analysis of a case of transfusion error in emergency ward that could have been fatal. After reporting of the mentioned event, through reviewing records and interviews with the responsible personnel, the details of the incident were elaborated. Then, an expert panel meeting was held to define event timeline and the care and service delivery problems and discuss their underlying causes, safeguards and preventive measures. Root cause analysis of the mentioned event demonstrated that certain defects of the system and the ensuing errors were main causes of the event. It also points out systematic corrective actions. It can be concluded that health care organizations should endeavor to provide opportunities to discuss errors and adverse events and introduce preventive measures to find areas where resources need to be allocated to improve patient safety.

A Soil-Plate Based Pipeline for Assessing Cereal Root Growth in Response to Polyethylene Glycol (PEG)-Induced Water Deficit Stress.

Science.gov (United States)

Nelson, Sven K; Oliver, Melvin J

2017-01-01

Drought is a serious problem that causes losses in crop-yield every year, but the mechanisms underlying how roots respond to water deficit are difficult to study under controlled conditions. Methods for assaying root elongation and architecture, especially for seedlings, are commonly achieved on artificial media, such as agar, moistened filter paper, or in hydroponic systems. However, it has been demonstrated that measuring root characteristics under such conditions does not accurately mimic what is observed when plants are grown in soil. Morphological changes in root behavior occur because of differences in solute diffusion, mechanical impedance, exposure to light (in some designs), and gas exchange of roots grown under these conditions. To address such deficiencies, we developed a quantitative method for assaying seedling root lengths and germination in soil using a plate-based approach with wheat as a model crop. We also further developed the method to include defined water deficits stress levels using the osmotic properties of polyethylene glycol (PEG). Seeds were sown into soil-filled vertical plates and grown in the dark. Root length measurements were collected using digital photography through the transparent lid under green lighting to avoid effects of white light exposure on growth. Photographs were analyzed using the cross-platform ImageJ plugin, SmartRoot, which can detect root edges and partially automate root detection for extraction of lengths. This allowed for quick measurements and straightforward and accurate assessments of non-linear roots. Other measurements, such as root width or angle, can also be collected by this method. An R function was developed to collect exported root length data, process and reformat the data, and output plots depicting root/shoot growth dynamics. For water deficit experiments, seedlings were transplanted side-by-side into well-watered plates and plates containing PEG solutions to simulate precise water deficits.

A simple and reliable method to detect gamma irradiated lentil (Lens culinaris Medik.) seeds by germination efficiency and seedling growth test

International Nuclear Information System (INIS)

Chaudhuri, Sadhan K.

2002-01-01

Germination efficiency and root/shoot length of germinated seedling is proposed to identify irradiated lentil seeds. Germination percentage was reduced above 0.2 kGy and lentil seeds were unable to germinate above 1.0 kGy dose. The critical dose that prevented the root elongation varied from 0.1 to 0.5 kGy. The sensitivity of lentil seeds to gamma irradiation was inversely proportional to moisture content of the seeds. Radiation effects could be detected in seeds even 12 months storage after gamma irradiation

Characterizing the Suitability of Selected Indigenous Soil Improving Legumes in a Humid Tropical Environment Using Shoot and Root Attributes

Directory of Open Access Journals (Sweden)

Anikwe, MAN.

2003-01-01

Full Text Available We studied the biomass accumulation, root length, nodulation, and chemical composition of roots and shoot of ten indigenous soil improving legumes in a humid tropical ecosystem with the view to selecting species for soil improvement programmes. Two cultivars of Vigna unguiculata, and one each of Glycine max, Arachis hypogaea, Crotararia ochroleuca, Cajanus cajan, Pueraria phaseoloides, Lablab purpureus, Mucuna pruriens and Vigna subterranea as treatments were planted in 20 kg pots containing soil from an Oxic paleustalf in Nigeria. The pots were arranged in randomized complete block layout with three replications in a greenhouse at IITA Ibadan, Nigeria. Results from the work show that M. pruriens and C. cajan produced the highest quantity of biomass. Root elongation was highest in M. pruriens whereas A. hypogaea produced the most root nodules with native rhizobia. The highest quantity of nodule dry weight was produced by A. hypogaea and P. phaseoloides whereas most of the legumes except G. max and P. phaseoloides had high and statistically comparable N content of between 2.36 and 3.34 mg.kg-1 N. The results show that the legumes have different root and shoot characteristics, which should be taken into consideration when selecting species for soil improvement programmes.

Are lesions induced by ionizing radiation direct blocks to DNA chain elongation

International Nuclear Information System (INIS)

Painter, R.B.

1983-01-01

Ionizing radiation blocks DNA chain elongation in normal diploid fibroblasts but not in fibroblasts from patients with ataxia-telangiectasia, even though there are no differences in the damage induced between the two cell types. This difference suggests that radiation-induced lesions in DNA are not themselves blocks to chain elongation in ataxia cells and raises the possibility that in normal cells a mediator exists between DNA damage and chain termination

DNA Double Strand Break Response and Limited Repair Capacity in Mouse Elongated Spermatids

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Emad A. Ahmed

2015-12-01

Full Text Available Spermatids are extremely sensitive to genotoxic exposures since during spermiogenesis only error-prone non homologous end joining (NHEJ repair pathways are available. Hence, genomic damage may accumulate in sperm and be transmitted to the zygote. Indirect, delayed DNA fragmentation and lesions associated with apoptotic-like processes have been observed during spermatid elongation, 27 days after irradiation. The proliferating spermatogonia and early meiotic prophase cells have been suggested to retain a memory of a radiation insult leading later to this delayed fragmentation. Here, we used meiotic spread preparations to localize phosphorylate histone H2 variant (γ-H2AX foci marking DNA double strand breaks (DSBs in elongated spermatids. This technique enabled us to determine the background level of DSB foci in elongated spermatids of RAD54/RAD54B double knockout (dko mice, severe combined immunodeficiency SCID mice, and poly adenosine diphosphate (ADP-ribose polymerase 1 (PARP1 inhibitor (DPQ-treated mice to compare them with the appropriate wild type controls. The repair kinetics data and the protein expression patterns observed indicate that the conventional NHEJ repair pathway is not available for elongated spermatids to repair the programmed and the IR-induced DSBs, reflecting the limited repair capacity of these cells. However, although elongated spermatids express the proteins of the alternative NHEJ, PARP1-inhibition had no effect on the repair kinetics after IR, suggesting that DNA damage may be passed onto sperm. Finally, our genetic mutant analysis suggests that an incomplete or defective meiotic recombinational repair of Spo11-induced DSBs may lead to a carry-over of the DSB damage or induce a delayed nuclear fragmentation during the sensitive programmed chromatin remodeling occurring in elongated spermatids.

Root caries, root surface restorations and lifestyle factors in adult Danes

DEFF Research Database (Denmark)

Christensen, Lisa Bøge; Bardow, Allan; Ekstrand, Kim

2015-01-01

, tobacco use and oral hygiene routines were collected from 4369 adults aged 21-89 who took part in a survey covering 13 municipalities across Denmark. Uni- and multivariate logistic regression analyses were applied to analyse the relationship between the independent lifestyle variables and active caries...... consumption, as well as wearing dentures, were significantly associated with the occurrence of untreated caries and restored root surface lesions, especially in persons over 45. Thus, such lifestyle factors should be taken into consideration, identifying persons with a need of preventive dental services...

The PIN gene family in cotton (Gossypium hirsutum): genome-wide identification and gene expression analyses during root development and abiotic stress responses.

Science.gov (United States)

He, Peng; Zhao, Peng; Wang, Limin; Zhang, Yuzhou; Wang, Xiaosi; Xiao, Hui; Yu, Jianing; Xiao, Guanghui

2017-07-03

Cell elongation and expansion are significant contributors to plant growth and morphogenesis, and are often regulated by environmental cues and endogenous hormones. Auxin is one of the most important phytohormones involved in the regulation of plant growth and development and plays key roles in plant cell expansion and elongation. Cotton fiber cells are a model system for studying cell elongation due to their large size. Cotton is also the world's most utilized crop for the production of natural fibers for textile and garment industries, and targeted expression of the IAA biosynthetic gene iaaM increased cotton fiber initiation. Polar auxin transport, mediated by PIN and AUX/LAX proteins, plays a central role in the control of auxin distribution. However, very limited information about PIN-FORMED (PIN) efflux carriers in cotton is known. In this study, 17 PIN-FORMED (PIN) efflux carrier family members were identified in the Gossypium hirsutum (G. hirsutum) genome. We found that PIN1-3 and PIN2 genes originated from the At subgenome were highly expressed in roots. Additionally, evaluation of gene expression patterns indicated that PIN genes are differentially induced by various abiotic stresses. Furthermore, we found that the majority of cotton PIN genes contained auxin (AuxREs) and salicylic acid (SA) responsive elements in their promoter regions were significantly up-regulated by exogenous hormone treatment. Our results provide a comprehensive analysis of the PIN gene family in G. hirsutum, including phylogenetic relationships, chromosomal locations, and gene expression and gene duplication analyses. This study sheds light on the precise roles of PIN genes in cotton root development and in adaption to stress responses.

Analysis of unintended events in hospitals: inter-rater reliability of constructing causal trees and classifying root causes

NARCIS (Netherlands)

Smits, M.; Janssen, J.; Vet, de H.C.W.; Zwaan, L.; Timmermans, D.R.M.; Groenewegen, P.P.; Wagner, C.

2009-01-01

BACKGROUND: Root cause analysis is a method to examine causes of unintended events. PRISMA (Prevention and Recovery Information System for Monitoring and Analysis: is a root cause analysis tool. With PRISMA, events are described in causal trees and root causes are subsequently classified with the

Analysis of unintended events in hospitals : inter-rater reliability of constructing causal trees and classifying root causes

NARCIS (Netherlands)

Smits, M.; Janssen, J.; Vet, R. de; Zwaan, L.; Groenewegen, P.P.; Timmermans, D.

2009-01-01

Background. Root cause analysis is a method to examine causes of unintended events. PRISMA (Prevention and Recovery Information System for Monitoring and Analysis) is a root cause analysis tool. With PRISMA, events are described in causal trees and root causes are subsequently classified with the

Analysis of unintended events in hospitals: inter-rater reliability of constructing causal trees and classifying root causes.

NARCIS (Netherlands)

Smits, M.; Janssen, J.; Vet, R. de; Zwaan, L.; Timmermans, D.; Groenewegen, P.; Wagner, C.

2009-01-01

Background: Root cause analysis is a method to examine causes of unintended events. PRISMA (Prevention and Recovery Information System for Monitoring and Analysis) is a root cause analysis tool. With PRISMA, events are described in causal trees and root causes are subsequently classified with the

Methanol as an alternative electron donor in chain elongation for butyrate and caproate formation

NARCIS (Netherlands)

Chen, W.S.; Ye, Y.; Steinbusch, K.J.J.; Strik, D.P.B.T.B.; Buisman, C.J.N.

2016-01-01

Chain elongation is an emerging mixed culture biotechnology converting acetate into valuable biochemicals by using ethanol as an external electron donor. In this study we proposed to test another potential electron donor, methanol, in chain elongation. Methanol can be produced through the

Suppression of vertical instability in elongated current-carrying plasmas by applying stellarator rotational transform

International Nuclear Information System (INIS)

ArchMiller, M. C.; Cianciosa, M. R.; Ennis, D. A.; Hanson, J. D.; Hartwell, G. J.; Hebert, J. D.; Herfindal, J. L.; Knowlton, S. F.; Ma, X.; Maurer, D. A.; Pandya, M. D.; Traverso, P.

2014-01-01

The passive stability of vertically elongated current-carrying toroidal plasmas has been investigated in the Compact Toroidal Hybrid, a stellarator/tokamak hybrid device. In this experiment, the fractional transform f, defined as the ratio of the imposed external rotational transform from stellarator coils to the total rotational transform, was varied from 0.04 to 0.50, and the elongation κ was varied from 1.4 to 2.2. Plasmas that were vertically unstable were evidenced by motion of the plasma in the vertical direction. Vertical drifts are measured with a set of poloidal field pickup coils. A three chord horizontally viewing interferometer and a soft X-ray diode array confirmed the drifts. Plasmas with low fractional transform and high elongation are the most susceptible to vertical instability, consistent with analytic predictions that the vertical mode in elongated plasmas can be stabilized by the poloidal field of a relatively weak stellarator equilibrium

The high temperature out-of-pile test of LVDT for elongation measurement of fuel pellet

Energy Technology Data Exchange (ETDEWEB)

Son, J. M.; Kim, B. K.; Jo, M. S.; Joo, K. N.; Park, S. J.; Gang, Y. H.; Kim, Y. J. [KAERI, Taejon (Korea, Republic of)

2003-10-01

As a part of the development of instrumentation technologies for the nuclear fuel irradiation test in HANARO(High-flux Advanced Nuclear Application Reactor), the elongation measurement technique of the fuel pellet is being developed using LVDT(Linear Variable Differential Transformer). The well qualified out-of-pile test were needed to understand the LVDT's detail characteristics at high temperature for the detail design of the fuel irradiation instrumented capsule, because LVDT is very sensitive to variation of temperature. Therefore, the high temperature out-of-pile test system for fuel pellet elongation was developed, and this test was performed under the temperature condition between room temperature and 300 .deg. C with increasing the elongation from 0 to 5 mm. The LVDT's high temperature characteristics and temperature sensitivity of LVDT were analyzed through this experiment. Based on the result of this test, the method for the application of LVDT and elongation detector at high temperature was introduced. It is known that the results will be used to predict accurately the elongation of fuel pellet during irradiation test.

Surgical management of aortic root disease in Marfan syndrome and other congenital disorders associated with aortic root aneurysms.

Science.gov (United States)

Treasure, Tom; Takkenberg, J J M; Pepper, John

2014-10-01

Elective root replacement in Marfan syndrome has improved life expectancy in affected patients. Three forms of surgery are now available: total root replacement (TRR) with a valved conduit, valve sparing root replacement (VSRR) and personalised external aortic root support (PEARS) with a macroporous mesh sleeve. TRR can be performed irrespective of aortic dimensions and a mechanical replacement valve is a secure and near certain means of correcting aortic valve regurgitation but has thromboembolic and bleeding risks. VSRR offers freedom from anticoagulation and attendant risks of bleeding but reoperation for aortic regurgitation runs at 1.3% per annum. A prospective multi-institutional study has found this to be an underestimate of the true rate of valve-related adverse events. PEARS conserves the aortic root anatomy and optimises the chance of maintaining valve function but average follow-up is under 5 years and so the long-term results are yet to be determined. Patients are on average in their 30s and so the cumulative lifetime need for reoperation, and of any valve-related complications, are consequently substantial. With lowering surgical risk of prophylactic root replacement, the threshold for intervention has reduced progressively over 30 years to 4.5 cm and so an increasing number of patients who are not destined to have a dissection are now having root replacement. In evaluation of these three forms of surgery, the number needed to treat to prevent dissection and the balance of net benefit and harm in future patients must be considered.

RNA-seq for gene identification and transcript profiling in relation to root growth of bermudagrass (Cynodon dactylon) under salinity stress.

Science.gov (United States)

Hu, Longxing; Li, Huiying; Chen, Liang; Lou, Yanhong; Amombo, Erick; Fu, Jinmin

2015-08-04

Soil salinity is one of the most significant abiotic stresses affecting plant shoots and roots growth. The adjustment of root architecture to spatio-temporal heterogeneity in salinity is particularly critical for plant growth and survival. Bermudagrass (Cynodon dactylon) is a widely used turf and forage perennial grass with a high degree of salinity tolerance. Salinity appears to stimulate the growth of roots and decrease their mortality in tolerant bermudagrass. To estimate a broad spectrum of genes related to root elongation affected by salt stress and the molecular mechanisms that control the positive response of root architecture to salinity, we analyzed the transcriptome of bermudagrass root tips in response to salinity. RNA-sequencing was performed in root tips of two bermudagrass genotypes contrasting in salt tolerance. A total of 237,850,130 high quality clean reads were generated and 250,359 transcripts were assembled with an average length of 1115 bp. Totally, 103,324 unigenes obtained with 53,765 unigenes (52 %) successfully annotated in databases. Bioinformatics analysis indicated that major transcription factor (TF) families linked to stress responses and growth regulation (MYB, bHLH, WRKY) were differentially expressed in root tips of bermudagrass under salinity. In addition, genes related to cell wall loosening and stiffening (xyloglucan endotransglucosylase/hydrolases, peroxidases) were identified. RNA-seq analysis identified candidate genes encoding TFs involved in the regulation of lignin synthesis, reactive oxygen species (ROS) homeostasis controlled by peroxidases, and the regulation of phytohormone signaling that promote cell wall loosening and therefore root growth under salinity.

Influence of ovarian muscle contraction and oocyte growth on egg chamber elongation in Drosophila.

Science.gov (United States)

Andersen, Darcy; Horne-Badovinac, Sally

2016-04-15

Organs are formed from multiple cell types that make distinct contributions to their shape. The Drosophila egg chamber provides a tractable model to dissect such contributions during morphogenesis. Egg chambers consist of 16 germ cells (GCs) surrounded by a somatic epithelium. Initially spherical, these structures elongate as they mature. This morphogenesis is thought to occur through a 'molecular corset' mechanism, whereby structural elements within the epithelium become circumferentially organized perpendicular to the elongation axis and resist the expansive growth of the GCs to promote elongation. Whether this epithelial organization provides the hypothesized constraining force has been difficult to discern, however, and a role for GC growth has not been demonstrated. Here, we provide evidence for this mechanism by altering the contractile activity of the tubular muscle sheath that surrounds developing egg chambers. Muscle hypo-contraction indirectly reduces GC growth and shortens the egg, which demonstrates the necessity of GC growth for elongation. Conversely, muscle hyper-contraction enhances the elongation program. Although this is an abnormal function for this muscle, this observation suggests that a corset-like force from the egg chamber's exterior could promote its lengthening. These findings highlight how physical contributions from several cell types are integrated to shape an organ. © 2016. Published by The Company of Biologists Ltd.

Elongational viscosity of monodisperse and bidisperse polystyrene melts

DEFF Research Database (Denmark)

Nielsen, Jens Kromann; Rasmussen, Henrik Koblitz; Hassager, Ole

2005-01-01

The startup and steady uniaxial elongational viscosity have been measured for two monodisperse polystyrene melts with molecular weights of 52 kg/mole (PS52K) and 103 kg/mole (PS103K), and for three bidisperse polystyrene melts. The bidisperse melts consist of PS103K or PS52K and a monodisperse...... (closed loop proportional regulator) using the laser in such a way that the stretch rate at the neck is kept constant. The rheometer has been described in more detail in (A. Bach, H.K. Rasmussen and O. Hassager, Journal of Rheology, 47 (2003) 429). PS390K show a decrease in the steady viscosity as a power......-law function of the elongational rate (A. Bach, K. Almdal, H.K. Rasmussen and O. Hassager, Macromolecules 36 (2003) 5174). PS52K and PS103K show that the steady viscosity has a maximum that is respectively 100% and 50% above 3 times the zero-shear-rate viscosity. The bidisperse melts show a significant...

Hamstring Elongation Quantified Using Ultrasonography During the Straight Leg Raise Test in Individuals With Low Back Pain.

Science.gov (United States)

Kellis, Eleftherios; Ellinoudis, Athanasios; Kofotolis, Nikolaos

2015-06-01

Although the straight leg raise (SLR) test frequently is used to assess hamstring extensibility in individuals with low back pain (LBP), evidence relating LBP, SLR, and hamstring extensibility remains unclear. The SLR measures the angle between the lifted leg and the horizontal, however, and, as such, it is not a direct measure of the elongation capacity of the hamstrings. To examine the differences in hamstring elongation (quantified via ultrasonography) and SLR score between individuals with LBP and asymptomatic controls and to determine the relationship between hamstring elongation, SLR, and functional disability scores. Cross-sectional study. University laboratory. Forty men and women with chronic LBP (mean ± SD, age 43.51 ± 3.71 years and 40 control subjects (age 45.11 ± 4.01 years) participated in this study. Passive SLR, elongation assessed via ultrasonography, and functional disability. SLR score, elongation of tendinous tissue within the semitendinosus muscle, and Oswestry Disability Index. Two-way analysis of variance tests indicated a significantly lower SLR score and a greater Oswestry score in LBP group compared with control subjects (P hamstring elongation (P > .05). Gender did not have an effect on all dependent measures (P > .05). Hamstring elongation showed a low correlation with SLR score and a minimal correlation with Oswestry score. These results indicate that the SLR score is not determined by hamstring elongation (quantified via ultrasonography). Copyright © 2015 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Methanofullerene elongated nanostructure formation for enhanced organic solar cells

Energy Technology Data Exchange (ETDEWEB)

Reyes-Reyes, M. [Instituto de Investigacion en Comunicacion Optica, Universidad Autonoma de San Luis Potosi, Alvaro Obregon 64, San Luis Potosi (Mexico)], E-mail: reyesm@cactus.iico.uaslp.mx; Lopez-Sandoval, R. [Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la presa San Jose 2055, CP 78216. San Luis Potosi (Mexico); Arenas-Alatorre, J. [Instituto de Fisica, UNAM, Apartado Postal 20-364, 01000, Mexico, D.F. (Mexico); Garibay-Alonso, R. [Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la presa San Jose 2055, CP 78216. San Luis Potosi (Mexico); Carroll, D.L. [Center for Nanotechnology and Molecular Materials, Department of Physics. Wake Forest University, Winston-Salem NC 27109 (United States); Lastras-Martinez, A. [Instituto de Investigacion en Comunicacion Optica, Universidad Autonoma de San Luis Potosi, Alvaro Obregon 64, San Luis Potosi (Mexico)

2007-11-01

Using transmission electron microscopy (TEM) and Z-contrast imaging we have demonstrated elongated nanostructure formation of fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) within an organic host through annealing. The annealing provides an enhanced mobility of the PCBM molecules and, with good initial dispersion, allows for the formation of exaggerated grain growth within the polymer host. We have assembled these nanostructures within the regioregular conjugated polymer poly(3-hexylthiophene) (P3HT). This PCBM elongated nanostructure formation maybe responsible for the very high efficiencies observed, at very low loadings of PCBM (1:0.6, polymer to PCBM), in annealed photovoltaics. Moreover, our high resolution TEM and electron energy loss spectroscopy studies clearly show that the PCBM crystals remain crystalline and are unaffected by the 200-keV electron beam.

Methanofullerene elongated nanostructure formation for enhanced organic solar cells

International Nuclear Information System (INIS)

Reyes-Reyes, M.; Lopez-Sandoval, R.; Arenas-Alatorre, J.; Garibay-Alonso, R.; Carroll, D.L.; Lastras-Martinez, A.

2007-01-01

Using transmission electron microscopy (TEM) and Z-contrast imaging we have demonstrated elongated nanostructure formation of fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) within an organic host through annealing. The annealing provides an enhanced mobility of the PCBM molecules and, with good initial dispersion, allows for the formation of exaggerated grain growth within the polymer host. We have assembled these nanostructures within the regioregular conjugated polymer poly(3-hexylthiophene) (P3HT). This PCBM elongated nanostructure formation maybe responsible for the very high efficiencies observed, at very low loadings of PCBM (1:0.6, polymer to PCBM), in annealed photovoltaics. Moreover, our high resolution TEM and electron energy loss spectroscopy studies clearly show that the PCBM crystals remain crystalline and are unaffected by the 200-keV electron beam

Applied force and elongation in the medial rectus in esotropic patients with and without movement restriction.

Science.gov (United States)

Krieger, Fernanda; Cvintal, Tadeu; Bicas, Harley

2004-12-01

To study the different ways of expressing the force-elongation relationship in medial rectus muscles in esotropia with and without muscular restriction. Twenty-nine passive force-elongation curves were obtained without restriction (group I, n = 13) and with restriction (group II, n = 10) by means of a manual pachymeter and a digital dynamometer. In group I, the mean age was 14 years and 7 days and the mean esotropia was 53.88(Delta) while in group II the mean age was 35 years and 5 days and the mean esotropia was 60.5(Delta). Comparisons of structural muscular parameters between groups I and II were made for length (38.69 +/- 0.75 vs. 32.48 +/- 1.84 mm, p elongation relationship, whether normalized or not, followed an exponential curve. The constant c, which represents force when the elongation is zero, remained the same in all curves. In contrast, the constant b, which represents the slope of the curve, showed a significant difference between the two groups only for the curves of force-absolute elongation and tension-absolute elongation. The results imply that the constant b is better for characterizing the difference between the behavior of the medial rectus in esotropia with and without restriction. In addition, the elongation normalization showed that the contractile component is similar between the two groups and, therefore, the classical way of analysis, which does not employ normalization, is appropriate to correlate muscle properties with clinical findings.

Inhibition of polar calcium movement and gravitropism in roots treated with auxin-transport inhibitors

Science.gov (United States)

Lee, J. S.; Mulkey, T. J.; Evans, M. L.

1984-01-01

Primary roots of maize (Zea mays L.) and pea (Pisum sativum L.) exhibit strong positive gravitropism. In both species, gravistimulation induces polar movement of calcium across the root tip from the upper side to the lower side. Roots of onion (Allium cepa L.) are not responsive to gravity and gravistimulation induces little or no polar movement of calcium across the root tip. Treatment of maize or pea roots with inhibitors of auxin transport (morphactin, naphthylphthalamic acid, 2,3,5-triiodobenzoic acid) prevents both gravitropism and gravity-induced polar movement of calcium across the root tip. The results indicate that calcium movement and auxin movement are closely linked in roots and that gravity-induced redistribution of calcium across the root cap may play an important role in the development of gravitropic curvature.

Glycan elongation beyond the mucin associated Tn antigen protects tumor cells from immune-mediated killing.

Directory of Open Access Journals (Sweden)

Caroline B Madsen

Full Text Available Membrane bound mucins are up-regulated and aberrantly glycosylated during malignant transformation in many cancer cells. This results in a negatively charged glycoprotein coat which may protect cancer cells from immune surveillance. However, only limited data have so far demonstrated the critical steps in glycan elongation that make aberrantly glycosylated mucins affect the interaction between cancer cells and cytotoxic effector cells of the immune system. Tn (GalNAc-Ser/Thr, STn (NeuAcα2-6GalNAc-Ser/Thr, T (Galβ1-3GalNAc-Ser/Thr, and ST (NeuAcα2-6Galβ1-3GalNAc-Ser/Thr antigens are recognized as cancer associated truncated glycans, and are expressed in many adenocarcinomas, e.g. breast- and pancreatic cancer cells. To investigate the role of the cancer associated glycan truncations in immune-mediated killing we created glyco-engineered breast- and pancreatic cancer cells expressing only the shortest possible mucin-like glycans (Tn and STn. Glyco-engineering was performed by zinc finger nuclease (ZFN knockout (KO of the Core 1 enzyme chaperone COSMC, thereby preventing glycan elongation beyond the initial GalNAc residue in O-linked glycans. We find that COSMC KO in the breast and pancreatic cancer cell lines T47D and Capan-1 increases sensitivity to both NK cell mediated antibody-dependent cellular-cytotoxicity (ADCC and cytotoxic T lymphocyte (CTL-mediated killing. In addition, we investigated the association between total cell surface expression of MUC1/MUC16 and NK or CTL mediated killing, and observed an inverse correlation between MUC16/MUC1 expression and the sensitivity to ADCC and CTL-mediated killing. Together, these data suggest that up-regulation of membrane bound mucins protects cells from immune mediated killing, and that particular glycosylation steps, as demonstrated for glycan elongation beyond Tn and STn, can be important for fine tuning of the immune escape mechanisms in cancer cells.

Genetic association among root morphology, root quality and root yield in ashwagandha (Withania somnifera)

OpenAIRE

Kumar Ramesh R.; Reddy Anjaneya Prasanna L.; Subbaiah Chinna J.; Kumar Niranjana A.; Prasad Nagendra H.N.; Bhukya Balakishan

2011-01-01

Ashwagandha (Withania somnifera) is a dryland medicinal crop and roots are used as valuable drug in traditional systems of medicine. Morphological variants (morphotypes) and the parental populations were evaluated for root - morphometric, quality and yield traits to study genetic association among them. Root morphometric traits (root length, root diameter, number of secondary roots/ plant) and crude fiber content exhibited strong association among them and ...

Comparative assessment of fluorosed and nonfluorosed fibroblast attachment on fluorosed and nonfluorosed teeth after scaling and root planning and ethylenediaminetetraacetic acid root biomodification

Directory of Open Access Journals (Sweden)

Kharidi Laxman Vandana

2014-01-01

Full Text Available Background and Objectives: Fluorosis causes mineralization changes in the tooth and can lead to morphological alterations of fibroblasts. To evaluate the effect of fluorosis on periodontal healing, the initial step while healing such as, fibroblast attachment onto the root surface requires to be evaluated on the fluorosed and nonfluorosed tooth using nonfluorosed as well as fluorosed fibroblasts originated from the subjects influenced by high-water fluoride. Hence, the objective of the current study was to study and compare the attachment of nonfluorosed and fluorosed fibroblasts on the fluorosed and nonfluorosed root fragments. Materials and Methods: A total of 112 fluorosed and nonfluorosed, periodontally healthy and diseased tooth roots were obtained and allotted to eight groups : f0 luorosed healthy (FH and non-FH (NFH controls, fluorosed diseased (FD and non-FD (NFD controls, fluorosed and nonfluorosed teeth treated with scaling and root planning (SRP (FD SRP and NFD SRP and similar groups treated with SRP and ethylenediaminetetraacetic acid (EDTA (FD SRP + EDTA and NFD SRP + EDTA burnishing treatment with 24% EDTA gel for 2 min. After the respective treatment half of the root fragments in each group were incubated in the human periodontal ligament fibroblast cells obtained and cultured from freshly extracted FH and NFH human premolar tooth root. The nonfluorosed fibroblasts are elongated, flat cells thus they show increased attachment to root the surface. Results: When comparison was carried out between the attachment of fluorosed and nonfluorosed fibroblasts on NFD groups treated with scaling and EDTA, significant results were obtained with increased attachment seen on the group incubated with nonfluorosed fibroblasts (P = 0.029. While on comparison between the attachment of fluorosed and nonfluorosed fibroblasts on NFH group, NFD group treated with SRP and NFD group, no significant results were obtained (P > 0.05. On comparison between

The crystal structure of elongation factor G complexed with GDP, at 2.7 A resolution.

OpenAIRE

Czworkowski, J; Wang, J; Steitz, T A; Moore, P B

1994-01-01

Elongation factor G (EF-G) catalyzes the translocation step of protein synthesis in bacteria, and like the other bacterial elongation factor, EF-Tu--whose structure is already known--it is a member of the GTPase superfamily. We have determined the crystal structure of EF-G--GDP from Thermus thermophilus. It is an elongated molecule whose large, N-terminal domain resembles the G domain of EF-Tu, except for a 90 residue insert, which covers a surface that is involved in nucleotide exchange in E...

Comparison of antimicrobial activity of traditional and new developed root sealers against pathogens related root canal

Directory of Open Access Journals (Sweden)

Joo-Hee Shin

2018-03-01

Full Text Available Background/purpose: Bacterial infection is closely associated with the failure of endodontic treatment, and use of endodontic sealer with antimicrobial activity and biological compatibility is necessary for the success of root canal treatment. The purpose of this study was to investigate and to compare the antibacterial effect of two calcium silicate-based root canal sealers (Endoseal and EndoSequence BC sealer as recent development sealers and with three conventional root canal sealers (AH Plus, Sealapex, and Tubli-Seal, before or after setting, on Porphyromonas endodontalis, Porphyromonas gingivalis, and Enterococcus faecalis. Materials and methods: The sealers were soaked in phosphate buffered saline to elute its compositions after and before setting, and the elutes were performed the antimicrobial assay. Also, X-ray fluorescence analysis was carried out to compare compositions of two calcium silicate-based sealers. Results: The conventional root canal sealers have strong antibacterial activity against the Gram-negative bacteria, P. endodontalis and P. gingivalis. Endoseal sealer showed antibacterial activity against not only the Gram-negative bacteria, but also against the Gram-positive bacteria, E. faecalis. However, Endosequence BC sealer exhibited a weak antibacterial effect on all bacteria in this study. X-ray fluorescence analysis exhibited that Endoseal contained more types and more amount of the oxide compound known to have strong antimicrobial activity such as Al2O3, Fe2O3, MgO, Na2O, NiO, and SO2 than Endoseqeunce BC. Conclusion: Endoseal, which contains various types of oxide compounds, seems to be a suitable sealer for preventing bacterial infection in both treated and untreated root canals. Keywords: Root canal sealer, Antimicrobial activity, Oxide compound, E. faecalis

Apparatus and method for preventing the rotation of rods used in nuclear fuel assemblies

International Nuclear Information System (INIS)

Pilgrim, L.G. Jr.; Jackson, L.F.

1985-01-01

Apparatus and method for preventing the rotation of one or more elongated rods used in nuclear fuel assemblies include an end plug secured to one longitudinal end of such an elongated rod and having an out-of-cavity, non-round structure affixed thereto and configured to mate with a complementary shaped structure in a lower tie plate of a nuclear fuel assembly in such a manner as to prevent the rotation of the rod about its longitudinal axis. In one embodiment, the end plug includes a pair of flats formed on a portion of the end plug and configured to abut against a pair of flats formed on the outer surface of a cylindrical boss or sleeve of the lower tie plate, thereby to prevent the rotation of the rod. In another embodiment, four grooves, disposed 90 0 apart about the periphery of an end plug of a rod form a spline. The grooves are configured to receive four, radially inwardly protruding, key members disposed 90 0 apart about the periphery of a sleeve secured to the lower tie plate, thereby to prevent the rotation of the rod. In a further embodiment, a sleeve is secured to an end plug of a rod and includes four elongated slots disposed 90 0 apart about the periphery of the sleeve and configured in width, depth and spacing to receive and mate with four web portions of the lower tie plate of the nuclear fuel assembly, thereby to secure the rod against rotation about its longitudinal axis

Adiabatic compression of elongated field-reversed configurations

International Nuclear Information System (INIS)

Spencer, R.L.; Tuszewski, M.; Linford, R.K.

1983-01-01

The adiabatic compression of an elongated field-reversed configuration (FRC) is computed by using a one-dimensional approximation. The one-dimensional results are checked against a two-dimensional equilibrium code. For ratios of FRC separatrix length to separatrix radius greater than about ten, the one-dimensional results are accurate within 10%. To this accuracy, the adiabatic compression of FRC's can be described by simple analytic formulas

Improving the Determination of Eastern Elongations of Planetary Satellites in the Astronomical Almanac

Science.gov (United States)

Rura, Christopher; Stollberg, Mark

2018-01-01

The Astronomical Almanac is an annual publication of the US Naval Observatory (USNO) and contains a wide variety of astronomical data used by astronomers worldwide as a general reference or for planning observations. Included in this almanac are the times of greatest eastern and northern elongations of the natural satellites of the planets, accurate to 0.1 hour UT. The production code currently used to determine elongation times generates X and Y coordinates for each satellite (16 total) in 5 second intervals. This consequentially caused very large data files, and resulted in the program devoted to determining the elongation times to be computationally intensive. To make this program more efficient, we wrote a Python program to fit a cubic spline to data generated with a 6-minute time step. This resulted in elongation times that were found to agree with those determined from the 5 second data currently used in a large number of cases and was tested for 16 satellites between 2017 and 2019. The accuracy of this program is being tested for the years past 2019 and, if no problems are found, the code will be considered for production of this section of The Astronomical Almanac.

Gravimorphism in rice and barley: promotion of leaf elongation by vertical inversion in agravitropically growing plants.

Science.gov (United States)

Abe, K; Takahashi, H; Suge, H

1998-12-01

We have compared shoot responses of agravitropic rice and barley plants to vertical inversion with those of normal ones. When rice plants were vertically inverted, the main stems of a japonica type of rice, cv. Kamenoo, showed negative gravitropism at nodes 2-15 of both elongated and non-elongated internodes. However, shoots of lazy line of rice, lazy-Kamenoo, bent gravitropically at nodes 11-15 only elongated internodes but not at nodes 2-10 of non-elongated ones. Thus, shoots of Kamenoo responded gravitropically at all stages of growth, whereas shoots of lazy-Kamenoo did not show gravitropic response before heading. In Kamenoo plants, lengths of both leaf-sheath and leaf-blade were shortened by vertical inversion, but those of the vertically inverted plants of lazy-Kamenoo were significantly longer than the plants in an upright position. When agravitropic and normal plants of barley were vertically inverted, the same results as in rice were obtained; elongation of both leaf-sheath and leaf-blade was inhibited in normal barley plants, Chikurin-Ibaragi No. 1, but significantly stimulated in agravitropic plants of serpentina barley. These results suggest that vertical inversion of rice and barley plants enhances the elongation growth of leaves in the absence of tropistic response.

Chain elongation and cyclization in type III PKS DpgA.

Science.gov (United States)

Wu, Hai-Chen; Li, Yi-San; Liu, Yu-Chen; Lyu, Syue-Yi; Wu, Chang-Jer; Li, Tsung-Lin

2012-04-16

Chain elongation and cyclization of precursors of dihydroxyphenylacetyl-CoA (DPA-CoA) catalyzed by the bacterial type III polyketide synthase DpgA were studied. Two labile intermediates, di- and tri-ketidyl-CoA (DK- and TK-CoA), were proposed and chemically synthesized. In the presence of DpgABD, each of these with [(13)C(3)]malonyl-CoA (MA-CoA) was able to form partially (13)C-enriched DPA-CoA. By NMR and MS analysis, the distribution of (13)C atoms in the partially (13)C-enriched DPA-CoA shed light on how the polyketide chain elongates and cyclizes in the DpgA-catalyzed reaction. Polyketone intermediates elongate in a manner different from that which had been believed: two molecules of DK-CoA, or one DK-CoA plus one acetoacetyl-CoA (AA-CoA), but not two molecules of AA-CoA can form one molecule of DPA-CoA. As a result, polyketidyl-CoA serves as both the starter and extender, whereas polyketone-CoA without the terminal carboxyl group can only act as an extender. The terminal carboxyl group is crucial for the cyclization that likely takes place on CoA. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Promoting chain elongation in mixed culture acidification reactors by addition of ethanol

International Nuclear Information System (INIS)

Grootscholten, T.I.M.; Kinsky dal Borgo, F.; Hamelers, H.V.M.; Buisman, C.J.N.

2013-01-01

In this research we investigate a microbial production process to produce medium chain fatty acids (MCFAs) based on the organic fraction of municipal solid waste (OFMSW). In this microbial production process, called chain elongation, bacteria produce medium chain fatty acids (MCFAs) from ethanol and volatile fatty acids (VFAs). MCFAs could be used as new biomass based building blocks for the chemical and fuel industry. The objective of this article is to investigate whether chain elongation can be promoted during acidification of OFMSW by addition of ethanol. The results show that chain elongation can be promoted during acidification of OFMSW by addition of ethanol. However, the hydrolysis rate and the carboxylic acid yield of the OFMSW in reactors with ethanol additions were lower than the hydrolysis rate and the carboxylic acid yield than in reactors without ethanol additions. Further research is required to determine whether a combined chain elongation and acidification reactor or a separated reactor system is more advantageous for MCFA production from OFMSW. -- Highlights: ► Production of medium chain fatty acids from municipal solid waste and ethanol. ► Insight in production of caproate and consumption of in-situ produced ethanol. ► Ethanol additions reduced propionate, butyrate and valerate concentrations. ► Ethanol additions hardly reduced acetate concentrations. ► Hydrolysis rate was lower in experiments with ethanol additions

Root rots

Science.gov (United States)

Kathryn Robbins; Philip M. Wargo

1989-01-01

Root rots of central hardwoods are diseases caused by fungi that infect and decay woody roots and sometimes also invade the butt portion of the tree. By killing and decaying roots, root rotting fungi reduce growth, decrease tree vigor, and cause windthrow and death. The most common root diseases of central hardwoods are Armillaria root rot, lnonotus root rot, and...

Towards an understanding of structure-function relationships of elongation factor Tu

DEFF Research Database (Denmark)

Wiborg, O; Andersen, C; Knudsen, Charlotte Rohde

1994-01-01

In light of the recently determined structure of elongation factor Tu, and taking into account chemical studies mapping functional sites, a number of residues have been selected for site-directed mutagenesis studies. Gly94, Gly126, His66, His118, Lys89 and Asp90 have each been point-mutated. Prel......In light of the recently determined structure of elongation factor Tu, and taking into account chemical studies mapping functional sites, a number of residues have been selected for site-directed mutagenesis studies. Gly94, Gly126, His66, His118, Lys89 and Asp90 have each been point...

Epimerization-free C-terminal peptide activation, elongation and cyclization

NARCIS (Netherlands)

Popović, S.

2015-01-01

C-terminal peptide activation and cyclization reactions are generally accompanied with epimerization (partial loss of C‐terminal stereointegrity). Therefore, the focus of this thesis was to develop epimerization-free methods for C-terminal peptide activation to enable C-terminal peptide elongation

Adiabatic compression of elongated field-reversed configurations

Energy Technology Data Exchange (ETDEWEB)

Spencer, R.L.; Tuszewski, M.; Linford, R.K.

1983-06-01

The adiabatic compression of an elongated field-reversed configuration (FRC) is computed by using a one-dimensional approximation. The one-dimensional results are checked against a two-dimensional equilibrium code. For ratios of FRC separatrix length to separatrix radius greater than about ten, the one-dimensional results are accurate within 10%. To this accuracy, the adiabatic compression of FRC's can be described by simple analytic formulas.

Root diseases, climate change and biomass productivity

International Nuclear Information System (INIS)

Warren, G.R.; Cruickshank, M.

2004-01-01

Tree growth and yield in eastern boreal spruce fir forests are both greatly affected by root and butt rots. These pests are also prevalent in western coniferous species and boreal-sub-boreal forests. Infections are difficult to detect, but reduced growth, tree mortality, wind throw and scaled butt cull contribute to considerable forest gaps. Harvesting and stand tending practices in second growth stands are creating conditions for increased incidence. Tree stress is one of the major factors affecting the spread of root disease. It is expected that climate change will create abnormal stress conditions that will further compound the incidence of root disease. A comparison was made between natural and managed stands, including harvesting and stand practices such as commercial thinning. Studies of Douglas-fir forests in British Columbia were presented, with results indicating that managed forests contain one third to one half less carbon biomass than unmanaged forests. It was concluded that root diseases must be recognized and taken into account in order to refine and improve biomass estimates, prevent overestimation of wood supply models and avoid potential wood fibre losses. 40 refs., 2 figs.

The relationship between the types of axial elongation and the prevalence of lattice degeneration of the retina.

Science.gov (United States)

Yura, T

1998-02-01

To assess the relationship between the prevalence of lattice degeneration and the types of axial elongation. Nine hundred seventy eyes of 542 highly myopic patients with axial length of 26.00-31.99 mm were evaluated by using A-scan axial length measurements and fundus examinations. Then the prevalence of lattice degeneration was compared between eyes with posterior staphyloma and those without posterior staphyloma. At each axial length, lattice degeneration was more frequent in eyes without posterior staphyloma (the entire eye elongates) than those with posterior staphyloma (only the posterior pole elongates). The difference was statistically significant (plattice degeneration is influenced by the types of axial elongation in high myopic eyes.

A Simple Method for Assessing Severity of Common Root Rot on Barley

Directory of Open Access Journals (Sweden)

Mohammad Imad Eddin Arabi

2013-12-01

Full Text Available Common root rot caused by Cochliobolus sativus is a serious disease of barley. A simple and reliable method for assessing this disease would enhance our capacity in identifying resistance sources and developing resistant barley cultivars. In searching for such a method, a conidial suspension of C. sativus was dropped onto sterilized elongated subcrown internodes and incubated in sandwich filter paper using polyethylene transparent envelopes. Initial disease symptoms were easily detected after 48h of inoculation. Highly significant correlation coefficients were found in each experiment (A, B and C between sandwich filter paper and seedling assays, indicating that this testing procedure was reliable. The method presented facilitates a rapid pre-selection under uniform conditions which is of importance from a breeder’s point of view.

Predictors, prevention, and management of postoperative pain associated with nonsurgical root canal treatment: A systematic review

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Mothanna K. AlRahabi, PhD

2017-10-01

Full Text Available Postoperative pain after root canal treatment can be reduced by applying recent advances in endodontic techniques and equipment. This systematic review includes current knowledge about pain after nonsurgical root canal treatment, including predictors, related factors, effects of recent advances, and management. A literature search was performed using the PubMed, ScienceDirect, and Cochrane Library databases for articles published between 1990 and 2016. Search keywords included postoperative pain, nonsurgical treatment, single visit, recent advances in endodontics, and management of postoperative pain with endodontic treatment. Only original research studies were included; editorials, reviews, brief notes, conference proceedings, and letters to the editor were excluded. The initial search yielded 4941 articles, which were assessed and filtered using the selection criteria. Sixty-five studies met the inclusion criteria and were included in the review. The findings showed that pain after nonsurgical root canal treatment occurred in 3–69.3% of patients. Microorganisms were identified as the primary contributors to postoperative pain, and there was no significant difference in postoperative pain between single- and multiple-visit treatments. Postoperative pain after root canal treatment ranges from mild to moderate and occurs even after optimally performed procedures. Furthermore, adequate management of postoperative pain is often considered an indicator of clinical excellence. Application of recently developed endodontic techniques and devices will reduce postoperative pain. Furthermore, a flexible, severity-based drug administration plan can be used to control and manage pain after root canal treatment. Application of the current research findings will reduce pain following root canal treatment and improve patient outcomes.

Does shoot water status limit leaf expansion of nitrogen-deprived barley?

Science.gov (United States)

Dodd, I C; Munns, Rana; Passioura, J B

2002-08-01

The role of shoot water status in mediating the decline in leaf elongation rate of nitrogen (N)-deprived barley plants was assessed. Plants were grown at two levels of N supply, with or without the application of pneumatic pressure to the roots. Applying enough pressure (balancing pressure) to keep xylem sap continuously bleeding from the cut surface of a leaf allowed the plants to remain at full turgor throughout the experiments. Plants from which N was withheld required a greater balancing pressure during both day and night. This difference in balancing pressure was greater at high (2.0 kPa) than low (1.2 kPa) atmospheric vapour pressure deficit (VPD). Pressurizing the roots did not prevent the decline in leaf elongation rate induced by withholding N at either high or low VPD. Thus low shoot water status did not limit leaf growth of N-deprived plants.

Cessation of reproduction-related spine elongation after multiple breeding cycles in female naked mole-rats.

Science.gov (United States)

Dengler-Crish, Christine M; Catania, Kenneth C

2009-01-01

The breeding female or "queen" naked mole-rat has a uniquely elongated body morphology attributed to the lengthening of the lumbar vertebral column that occurs during pregnancy. It is unknown whether this vertebral growth is a continuous process, or associated only with early reproductive experience. We compared pregnancy-related bone elongation in nascent primiparous queens and established queens to determine if this vertebral expansion was a lifelong process in these females. We also investigated the impact of lactation on vertebral elongation in these mole-rats because it is known to be a time of significant bone loss in other mammals. Our data show that after eight or more pregnancies, established queens no longer experienced a net gain in lumbar spine length over the reproductive cycle, whereas the nascent breeders demonstrated significant spine lengthening over this time. Despite the lack of net spine lengthening in established breeders, our results indicated that these queens still experienced some pregnancy-specific vertebral elongation. In naked mole-rats, pregnancy-induced bone elongation may serve the dual purposes of first lengthening the spine, and then once optimal spine size is achieved, serving as a homeostatic mechanism that prepares the spine for the mineral demands of lactation. Anat Rec, 2009. (c) 2008 Wiley-Liss, Inc.

Characteristics of elongated and ruptured anterior cruciate ligament grafts: An analysis of 21 consecutive revision cases

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Kohei Iio

2017-04-01

Conclusion: The location of the original femoral tunnel was more proximal in patients with elongated grafts than in those with ruptured grafts. Different bone tunnel position from native ACL might lead to graft elongation.

Prediction of RNA Polymerase II recruitment, elongation and stalling from histone modification data

DEFF Research Database (Denmark)

Chen, Yun; Jørgensen, Mette; Kolde, Raivo

2011-01-01

of RNAPII stalling. CONCLUSIONS: In this study we introduce a general framework to accurately predict the level of RNAPII recruitment, elongation, stalling and mRNA expression from chromatin signals. The versatility of the method also makes it ideally suited to investigate other genomic data....... strategies are needed to progress from descriptive annotation of data to quantitative, predictive models. RESULTS: Here, we describe a computational framework which with high accuracy can predict the locations of core promoters, the amount of recruited RNAPII at the promoter, the amount of elongating RNAPII...... of these four marks are found to be necessary for recruitment of RNAPII but not sufficient for the elongation. We also show that the spatial distributions of histone marks are almost as predictive as the signal strength and that a set of histone marks immediately downstream of the TSS is highly predictive...

Positive grid corrosion elongation analysis using CAE with corrosion deformation transformed into thermal phenomenon

Science.gov (United States)

Mukaitani, Ichiroh; Hayashi, Koji; Shimoura, Ichiro; Takemasa, Arihiko; Takahashi, Isamu; Tsubakino, Harushige

Valve-regulated lead-acid (VRLA) batteries have been commercially available for more than 20 years and have been enthusiastically embraced by users of uninterruptible power supplies (UPS) because of the anticipated reduction in installation and operating costs, smaller footprint and fewer environmental concerns. In Japan, communication networks are demanding reduced costs and longer life from their batteries. Among the factors limiting the life of VRLA batteries, the corrosion of positive grid material has been proven to cause elongation of the plates, loss of electrical contact and shorter lifetime. The content of Sn is also a key factor and addition of Sn in the grid alloy results in better performance in creep resistance, tensile strength and corrosion resistance [R. David Prenagaman, The Battery Man, vol. 39, September 1997, p. 16. I. Mukaitani, T. Sakamoto, T. Kikuoka, Y. Yamaguchi, H. Tsubakino, Proceedings of the 40th Battery Symposium in Japan, 1999, p. 99]. A key point is what the ratio of Sn to Ca should be, since too much Sn may lead to even worse elongation of the plates [I. Mukaitani, T. Sakamoto, T. Kikuoka, Y. Yamaguchi, H. Tsubakino, Proceedings of the 40th Battery Symposium in Japan, 1999, p. 99]. We have determined that microstructure control with a composition of lead-calcium-tin (Pb-Ca-Sn) alloy is optimal for better performance of the plates [I. Mukaitani, T. Sakamoto, T. Kikuoka, Y. Yamaguchi, H. Tsubakino, Proceedings of the 40th Battery Symposium in Japan, 1999, p. 99]. We developed a "simulation of current collector corrosion elongation" which is a technique of estimating corrosion elongation from the current collector design [I. Mukaitani, K. Hayashi, I. Shimoura, H. Takabayashi, M. Terada, A. Takemasa, I. Takahashi, K. Okamoto, Proceedings of the 44th Battery Symposium in Japan, 2003, p. 652]. Corrosion elongation occurs as the corrosion material layer grows out of the current collector metal. We resolved this problem using generally CAD

Effects of wastewater discharge on formation of Fe plaque on root surface and radial oxygen loss of mangrove roots

Energy Technology Data Exchange (ETDEWEB)

Pi, N. [Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Kowloon (Hong Kong); Tam, N.F.Y., E-mail: bhntam@cityu.edu.h [Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Kowloon (Hong Kong); Wong, M.H. [Croucher Institute for Environmental Sciences, Baptist University of Hong Kong, Kowloon Tong, Kowloon (Hong Kong)

2010-02-15

Effects of wastewater discharge on radial oxygen loss (ROL), formation of iron (Fe) plaque on root surface, and their correlations in Bruguiera gymnorrhiza (L.) Poir and Excoecaria agallocha L. were investigated. ROL along a lateral root increased more rapidly in control than that in strong wastewater (with pollutant concentrations ten times of that in municipal sewage, 10NW) treatment, but less Fe plaque was formed in control for both plants. For B. gymnorrhiza receiving 10NW, Fe plaque formation was more at basal and mature zones than at root tip, while opposite trend was shown in E. agallocha. At day 0, the correlation between ROL and Fe plaque was insignificant, but negative and positive correlations were found in 10NW and control, respectively, at day 105, suggesting that more ROL was induced leading to more Fe plaque. However, excess Fe plaque also served as a 'barrier' to prevent excessive ROL in 10NW plants. - Correlation between Fe plaque formation and ROL.

Laser scanning dental probe for endodontic root canal treatment

Science.gov (United States)

Blank, Molly A. B.; Friedrich, Michal; Hamilton, Jeffrey D.; Lee, Peggy; Berg, Joel; Seibel, Eric J.

2011-03-01

Complications that arise during endodontic procedures pose serious threats to the long-term integrity and health of the tooth. Potential complexities of root canals include residual pulpal tissue, cracks, mesial-buccal 2 and accessory canals. In the case of a failed root canal, a successful apicoectomy can be jeopardized by isthmuses, accessory canals, and root microfracture. Confirming diagnosis using a small imaging probe would allow proper treatment and prevent retreatment of endodontic procedures. An ultrathin and flexible laser scanning endoscope of 1.2 to 1.6mm outer diameter was used in vitro to image extracted teeth with varied root configurations. Teeth were opened using a conventional bur and high speed drill. Imaging within the opened access cavity clarified the location of the roots where canal filing would initiate. Although radiographs are commonly used to determine the root canal size, position, and shape, the limited 2D image perspective leaves ambiguity that could be clarified if used in conjunction with a direct visual imaging tool. Direct visualization may avoid difficulties in locating the root canal and reduce the number of radiographs needed. A transillumination imaging device with the separated illumination and light collection functions rendered cracks visible in the prepared teeth that were otherwise indiscernible using reflected visible light. Our work demonstrates that a small diameter endoscope with high spatial resolution may significantly increase the efficiency and success of endodontic procedures.

Brassinosteroid regulates cell elongation by modulating gibberellin metabolism in rice.

Science.gov (United States)

Tong, Hongning; Xiao, Yunhua; Liu, Dapu; Gao, Shaopei; Liu, Linchuan; Yin, Yanhai; Jin, Yun; Qian, Qian; Chu, Chengcai

2014-11-01

Brassinosteroid (BR) and gibberellin (GA) are two predominant hormones regulating plant cell elongation. A defect in either of these leads to reduced plant growth and dwarfism. However, their relationship remains unknown in rice (Oryza sativa). Here, we demonstrated that BR regulates cell elongation by modulating GA metabolism in rice. Under physiological conditions, BR promotes GA accumulation by regulating the expression of GA metabolic genes to stimulate cell elongation. BR greatly induces the expression of D18/GA3ox-2, one of the GA biosynthetic genes, leading to increased GA1 levels, the bioactive GA in rice seedlings. Consequently, both d18 and loss-of-function GA-signaling mutants have decreased BR sensitivity. When excessive active BR is applied, the hormone mostly induces GA inactivation through upregulation of the GA inactivation gene GA2ox-3 and also represses BR biosynthesis, resulting in decreased hormone levels and growth inhibition. As a feedback mechanism, GA extensively inhibits BR biosynthesis and the BR response. GA treatment decreases the enlarged leaf angles in plants with enhanced BR biosynthesis or signaling. Our results revealed a previously unknown mechanism underlying BR and GA crosstalk depending on tissues and hormone levels, which greatly advances our understanding of hormone actions in crop plants and appears much different from that in Arabidopsis thaliana. © 2014 American Society of Plant Biologists. All rights reserved.

Fatty Acid Elongation in Non-Alcoholic Steatohepatitis and Hepatocellular Carcinoma

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Sonja M. Kessler

2014-04-01

Full Text Available Non-alcoholic steatohepatitis (NASH represents a risk factor for the development of hepatocellular carcinoma (HCC and is characterized by quantitative and qualitative changes in hepatic lipids. Since elongation of fatty acids from C16 to C18 has recently been reported to promote both hepatic lipid accumulation and inflammation we aimed to investigate whether a frequently used mouse NASH model reflects this clinically relevant feature and whether C16 to C18 elongation can be observed in HCC development. Feeding mice a methionine and choline deficient diet to model NASH not only increased total hepatic fatty acids and cholesterol, but also distinctly elevated the C18/C16 ratio, which was not changed in a model of simple steatosis (ob/ob mice. Depletion of Kupffer cells abrogated both quantitative and qualitative methionine-and-choline deficient (MCD-induced alterations in hepatic lipids. Interestingly, mimicking inflammatory events in early hepatocarcinogenesis by diethylnitrosamine-induced carcinogenesis (48 h increased hepatic lipids and the C18/C16 ratio. Analyses of human liver samples from patients with NASH or NASH-related HCC showed an elevated expression of the elongase ELOVL6, which is responsible for the elongation of C16 fatty acids. Taken together, our findings suggest a detrimental role of an altered fatty acid pattern in the progression of NASH-related liver disease.

Mutation of Rice BC12/GDD1, Which Encodes a Kinesin-Like Protein That Binds to a GA Biosynthesis Gene Promoter, Leads to Dwarfism with Impaired Cell Elongation[W][OA

Science.gov (United States)

Li, Juan; Jiang, Jiafu; Qian, Qian; Xu, Yunyuan; Zhang, Cui; Xiao, Jun; Du, Cheng; Luo, Wei; Zou, Guoxing; Chen, Mingluan; Huang, Yunqing; Feng, Yuqi; Cheng, Zhukuan; Yuan, Ming; Chong, Kang

2011-01-01

The kinesins are a family of microtubule-based motor proteins that move directionally along microtubules and are involved in many crucial cellular processes, including cell elongation in plants. Less is known about kinesins directly regulating gene transcription to affect cellular physiological processes. Here, we describe a rice (Oryza sativa) mutant, gibberellin-deficient dwarf1 (gdd1), that has a phenotype of greatly reduced length of root, stems, spikes, and seeds. This reduced length is due to decreased cell elongation and can be rescued by exogenous gibberellic acid (GA3) treatment. GDD1 was cloned by a map-based approach, was expressed constitutively, and was found to encode the kinesin-like protein BRITTLE CULM12 (BC12). Microtubule cosedimentation assays revealed that BC12/GDD1 bound to microtubules in an ATP-dependent manner. Whole-genome microarray analysis revealed the expression of ent-kaurene oxidase (KO2), which encodes an enzyme involved in GA biosynthesis, was downregulated in gdd1. Electrophoretic mobility shift and chromatin immunoprecipitation assays revealed that GDD1 bound to the element ACCAACTTGAA in the KO2 promoter. In addition, GDD1 was shown to have transactivation activity. The level of endogenous GAs was reduced in gdd1, and the reorganization of cortical microtubules was altered. Therefore, BC12/GDD1, a kinesin-like protein with transcription regulation activity, mediates cell elongation by regulating the GA biosynthesis pathway in rice. PMID:21325138

Elongation Factor Ts Directly Facilitates the Formation and Disassembly of the Escherichia coli Elongation Factor Tu·GTP·Aminoacyl-tRNA Ternary Complex*

Science.gov (United States)

Burnett, Benjamin J.; Altman, Roger B.; Ferrao, Ryan; Alejo, Jose L.; Kaur, Navdep; Kanji, Joshua; Blanchard, Scott C.

2013-01-01

Aminoacyl-tRNA enters the translating ribosome in a ternary complex with elongation factor Tu (EF-Tu) and GTP. Here, we describe bulk steady state and pre-steady state fluorescence methods that enabled us to quantitatively explore the kinetic features of Escherichia coli ternary complex formation and decay. The data obtained suggest that both processes are controlled by a nucleotide-dependent, rate-determining conformational change in EF-Tu. Unexpectedly, we found that this conformational change is accelerated by elongation factor Ts (EF-Ts), the guanosine nucleotide exchange factor for EF-Tu. Notably, EF-Ts attenuates the affinity of EF-Tu for GTP and destabilizes ternary complex in the presence of non-hydrolyzable GTP analogs. These results suggest that EF-Ts serves an unanticipated role in the cell of actively regulating the abundance and stability of ternary complex in a manner that contributes to rapid and faithful protein synthesis. PMID:23539628

Determinants of Elongation of the Labia Minora in Tete Province ...

African Journals Online (AJOL)

AJRH Managing Editor

women may not report current vaginal ill health, it is possible that prospective cohort ... Keywords: Labia minora elongation; vaginal practices; Mozambique; survey; cross-sectional studies. ..... had ever had vaginal discharge, which was most.

Mapping Escherichia coli elongation factor Tu residues involved in binding of aminoacyl-tRNA

DEFF Research Database (Denmark)

Wiborg, Ove; Andersen, C; Knudsen, Charlotte Rohde

1996-01-01

Two residues of Escherichia coli elongation factor Tu involved in binding of aminoacyl-tRNA were identified and subjected to mutational analysis. Lys-89 and Asn-90 were each replaced by either Ala or Glu. The four single mutants were denoted K89A, K89E, N90A, and N90E, respectively. The mutants...... were characterized with respect to thermal and chemical stability, GTPase activity, tRNA affinity, and activity in an in vitro translation assay. Most conspicuously tRNA affinities were reduced for all mutants. The results verify our structural analysis of elongation factor Tu in complex with aminoacyl....... Their functional roles are discussed in relation to the structure of elongation factor Tu in complex with aminoacyl-tRNA. Udgivelsesdato: 1996-Aug-23...

Ardnamurchan 3D cone-sheet architecture explained by a single elongate magma chamber.

Science.gov (United States)

Burchardt, Steffi; Troll, Valentin R; Mathieu, Lucie; Emeleus, Henry C; Donaldson, Colin H

2013-10-08

The Palaeogene Ardnamurchan central igneous complex, NW Scotland, was a defining place for the development of the classic concepts of cone-sheet and ring-dyke emplacement and has thus fundamentally influenced our thinking on subvolcanic structures. We have used the available structural information on Ardnamurchan to project the underlying three-dimensional (3D) cone-sheet structure. Here we show that a single elongate magma chamber likely acted as the source of the cone-sheet swarm(s) instead of the traditionally accepted model of three successive centres. This proposal is supported by the ridge-like morphology of the Ardnamurchan volcano and is consistent with the depth and elongation of the gravity anomaly underlying the peninsula. Our model challenges the traditional model of cone-sheet emplacement at Ardnamurchan that involves successive but independent centres in favour of a more dynamical one that involves a single, but elongate and progressively evolving magma chamber system.

Transcription elongation factor GreA has functional chaperone activity.

Science.gov (United States)

Li, Kun; Jiang, Tianyi; Yu, Bo; Wang, Limin; Gao, Chao; Ma, Cuiqing; Xu, Ping; Ma, Yanhe

2012-01-01

Bacterial GreA is an indispensable factor in the RNA polymerase elongation complex. It plays multiple roles in transcriptional elongation, and may be implicated in resistance to various stresses. In this study, we show that Escherichia coli GreA inhibits aggregation of several substrate proteins under heat shock condition. GreA can also effectively promote the refolding of denatured proteins. These facts reveal that GreA has chaperone activity. Distinct from many molecular chaperones, GreA does not form stable complexes with unfolded substrates. GreA overexpression confers the host cells with enhanced resistance to heat shock and oxidative stress. Moreover, GreA expression in the greA/greB double mutant could suppress the temperature-sensitive phenotype, and dramatically alleviate the in vivo protein aggregation. The results suggest that bacterial GreA may act as chaperone in vivo. These results suggest that GreA, in addition to its function as a transcription factor, is involved in protection of cellular proteins against aggregation.

IHH and FGF8 coregulate elongation of digit primordia.

Science.gov (United States)

Zhou, Jian; Meng, Junwei; Guo, Shengzhen; Gao, Bo; Ma, Gang; Zhu, Xuming; Hu, Jianxin; Xiao, Yue; Lin, Chuwen; Wang, Hongsheng; Ding, Lusheng; Feng, Guoyin; Guo, Xizhi; He, Lin

2007-11-23

In the developing limb bud, digit pattern arises from anterior-posterior (A-P) positional information which is provided by the concentration gradient of SHH. However, the mechanisms of translating early asymmetry into morphological form are still unclear. Here, we examined the ability of IHH and FGF8 signaling to regulate digital chondrogenesis, by implanting protein-loaded beads in the interdigital space singly and in combination. We found that IHH protein induced an elongated digit and that FGF8 protein blocked the terminal phalange formation. Molecular marker analysis showed that IHH expanded Sox9 expression in mesenchymal cells possibly through up-regulated FGF8 expression. Application of both IHH and FGF8 protein induced a large terminal phalange. These results suggest that both enhanced IHH and FGF8 signaling are required for the development of additional cartilage element in limbs. IHH and FGF8 maybe play different roles and act synergistically to promote chondrogenesis during digit primordia elongation.

Effectiveness of EDTA as the irrigation solution to remove smear layer in root canal

OpenAIRE

Kurniasri Amas Achiar; Endang Sukartini

2009-01-01

One of the objectives of successful endodontic treatment is the hermetic obturation of the root canal system. To achieve this, the root canal filling must seal the canal space both apically and coronally to prevent the ingress of microorganisms or tissue fluids into the canal space. Apical leakage is reported a common reason for the clinical failure of endodontic therapy. Leakage through an obturated root canal is expected to take place at interfaces between sealer and dentin or sealer and gu...

Induction of hairy roots by various strains of Agrobacterium rhizogenes in different types of Capsicum species explants.

Science.gov (United States)

Md Setamam, Nursuria; Jaafar Sidik, Norrizah; Abdul Rahman, Zainon; Che Mohd Zain, Che Radziah

2014-06-30

Capsicum annuum and Capsicum frutescens, also known as "chilies", belong to the Solanaceae family and have tremendous beneficial properties. The application of hairy root culture may become an alternative method for future development of these species by adding value, such as by increasing secondary metabolites and improving genetic and biochemical stability compared with normal Capsicum plants. Therefore, in this research, different types of explants of both species were infected with various Agrobacterium rhizogenes strains to provide more information about the morphology and induction efficiency of hairy roots. After 2 weeks of in vitro seed germination, young seedling explants were cut into three segments; the cotyledon, hypocotyl, and radical. Then, the explants were co-cultured with four isolated A. rhizogenes strains in Murashige & Skoog culture media (MS) containing decreasing carbenicillin disodium concentrations for one month. In this experiment, thick and short hairy roots were induced at all induction sites of C. annuum while thin, elongated hairy roots appeared mostly at wound sites of C. frutescens. Overall, the hairy root induction percentages of C. frutescens were higher compared with C. annuum. Hairy root initiation was observed earliest using radicles (1st week), followed by cotyledons (2nd week), and hypocotyls (3rd week). Cotyledon explants of both species had the highest induction frequency with all strains compared with the other explants types. Strains ATCC 13333 and ATCC 15834 were the most favourable for C. frutescens while ATCC 43056 and ATCC 43057 were the most favourable for C. annuum. The interactions between the different explants and strains showed significant differences with p-values Capsicum species. Both Capsicum species were amenable to A. rhizogenes infection and hairy root induction is recommended for use as an alternative explants in future plant-based studies.

Elongation of exogenous fatty acids by the bioluminescent bacterium Vibrio harveyi

Energy Technology Data Exchange (ETDEWEB)

Byers, D.M.

1989-01-01

Bioluminescent bacteria require myristic acid (C14:0) to produce the myristaldehyde substrate of the light-emitting luciferase reaction. Since both endogenous and exogenous C14:0 can be used for this purpose, the metabolism of exogenous fatty acids by luminescent bacteria has been investigated. Both Vibrio harveyi and Vibrio fischeri incorporated label from (1-14C)myristic acid (C14:0) into phospholipid acyl chains as well as into CO2. In contrast, Photobacterium phosphoreum did not exhibit phospholipid acylation or beta-oxidation using exogenous fatty acids. Unlike Escherichia coli, the two Vibrio species can directly elongate fatty acids such as octanoic (C8:0), lauric (C12:0), and myristic acid, as demonstrated by radio-gas liquid chromatography. The induction of bioluminescence in late exponential growth had little effect on the ability of V. harveyi to elongate fatty acids, but it did increase the amount of C14:0 relative to C16:0 labeled from (14C)C8:0. This was not observed in a dark mutant of V. harveyi that is incapable of supplying endogenous C14:0 for luminescence. Cerulenin preferentially decreased the labeling of C16:0 and of unsaturated fatty acids from all 14C-labeled fatty acid precursors as well as from (14C)acetate, suggesting that common mechanisms may be involved in elongation of fatty acids from endogenous and exogenous sources. Fatty acylation of the luminescence-related synthetase and reductase enzymes responsible for aldehyde synthesis exhibited a chain-length preference for C14:0, which also was indicated by reverse-phase thin-layer chromatography of the acyl groups attached to these enzymes. The ability of V. harveyi to activate and elongate exogenous fatty acids may be related to an adaptive requirement to metabolize intracellular C14:0 generated by the luciferase reaction during luminescence development.

Elongation of exogenous fatty acids by the bioluminescent bacterium Vibrio harveyi

International Nuclear Information System (INIS)

Byers, D.M.

1989-01-01

Bioluminescent bacteria require myristic acid (C14:0) to produce the myristaldehyde substrate of the light-emitting luciferase reaction. Since both endogenous and exogenous C14:0 can be used for this purpose, the metabolism of exogenous fatty acids by luminescent bacteria has been investigated. Both Vibrio harveyi and Vibrio fischeri incorporated label from [1-14C]myristic acid (C14:0) into phospholipid acyl chains as well as into CO2. In contrast, Photobacterium phosphoreum did not exhibit phospholipid acylation or beta-oxidation using exogenous fatty acids. Unlike Escherichia coli, the two Vibrio species can directly elongate fatty acids such as octanoic (C8:0), lauric (C12:0), and myristic acid, as demonstrated by radio-gas liquid chromatography. The induction of bioluminescence in late exponential growth had little effect on the ability of V. harveyi to elongate fatty acids, but it did increase the amount of C14:0 relative to C16:0 labeled from [14C]C8:0. This was not observed in a dark mutant of V. harveyi that is incapable of supplying endogenous C14:0 for luminescence. Cerulenin preferentially decreased the labeling of C16:0 and of unsaturated fatty acids from all 14C-labeled fatty acid precursors as well as from [14C]acetate, suggesting that common mechanisms may be involved in elongation of fatty acids from endogenous and exogenous sources. Fatty acylation of the luminescence-related synthetase and reductase enzymes responsible for aldehyde synthesis exhibited a chain-length preference for C14:0, which also was indicated by reverse-phase thin-layer chromatography of the acyl groups attached to these enzymes. The ability of V. harveyi to activate and elongate exogenous fatty acids may be related to an adaptive requirement to metabolize intracellular C14:0 generated by the luciferase reaction during luminescence development

Lithium treatment elongates primary cilia in the mouse brain and in cultured cells

Energy Technology Data Exchange (ETDEWEB)

Miyoshi, Ko, E-mail: miyoshi@cc.okayama-u.ac.jp [Department of Brain Science, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikatacho, Okayama 700-8558 (Japan); Kasahara, Kyosuke; Miyazaki, Ikuko; Asanuma, Masato [Department of Brain Science, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikatacho, Okayama 700-8558 (Japan)

2009-10-30

The molecular mechanisms underlying the therapeutic effects of lithium, a first-line antimanic mood stabilizer, have not yet been fully elucidated. Treatment of the algae Chlamydomonas reinhardtii with lithium has been shown to induce elongation of their flagella, which are analogous structures to vertebrate cilia. In the mouse brain, adenylyl cyclase 3 (AC3) and certain neuropeptide receptors colocalize to the primary cilium of neuronal cells, suggesting a chemosensory function for the primary cilium in the nervous system. Here we show that lithium treatment elongates primary cilia in the mouse brain and in cultured cells. Brain sections from mice chronically fed with Li{sub 2}CO{sub 3} were subjected to immunofluorescence study. Primary cilia carrying both AC3 and the receptor for melanin-concentrating hormone (MCH) were elongated in the dorsal striatum and nucleus accumbens of lithium-fed mice, as compared to those of control animals. Moreover, lithium-treated NIH3T3 cells and cultured striatal neurons exhibited elongation of the primary cilia. The present results provide initial evidence that a psychotropic agent can affect ciliary length in the central nervous system, and furthermore suggest that lithium exerts its therapeutic effects via the upregulation of cilia-mediated MCH sensing. These findings thus contribute novel insights into the pathophysiology of bipolar mood disorder and other psychiatric diseases.

Lithium treatment elongates primary cilia in the mouse brain and in cultured cells

International Nuclear Information System (INIS)

Miyoshi, Ko; Kasahara, Kyosuke; Miyazaki, Ikuko; Asanuma, Masato

2009-01-01

The molecular mechanisms underlying the therapeutic effects of lithium, a first-line antimanic mood stabilizer, have not yet been fully elucidated. Treatment of the algae Chlamydomonas reinhardtii with lithium has been shown to induce elongation of their flagella, which are analogous structures to vertebrate cilia. In the mouse brain, adenylyl cyclase 3 (AC3) and certain neuropeptide receptors colocalize to the primary cilium of neuronal cells, suggesting a chemosensory function for the primary cilium in the nervous system. Here we show that lithium treatment elongates primary cilia in the mouse brain and in cultured cells. Brain sections from mice chronically fed with Li 2 CO 3 were subjected to immunofluorescence study. Primary cilia carrying both AC3 and the receptor for melanin-concentrating hormone (MCH) were elongated in the dorsal striatum and nucleus accumbens of lithium-fed mice, as compared to those of control animals. Moreover, lithium-treated NIH3T3 cells and cultured striatal neurons exhibited elongation of the primary cilia. The present results provide initial evidence that a psychotropic agent can affect ciliary length in the central nervous system, and furthermore suggest that lithium exerts its therapeutic effects via the upregulation of cilia-mediated MCH sensing. These findings thus contribute novel insights into the pathophysiology of bipolar mood disorder and other psychiatric diseases.

Effect of applied synthetic auxin on root growth in plantlet propagation by cuttage and tissue culture; Sashiki to soshiki baiyo ni okeru gosei auxin rui no shiyo koka

Energy Technology Data Exchange (ETDEWEB)

Shoji, K; Yoshihara, T [Central Research Institute of Electric Power Industry, Tokyo (Japan)

1996-12-01

The effect of synthetic plant hormone 4-C1-IAA and TFIBA on root growth in plantlet propagation was clarified by the cuttage and the issue culture of strawberry seedling production. A periwinkle, vine, and azalea are the effect of 4-C1-IAA on root growth, and a promotion effect was recognized for rooting and root elongation. The concentration of 4-C1-IAA in which the growth promotion effect of a root most appears varies depending on the species of a plant. The concentration of a periwinkle was 20 ppm, and that of an azalea was 2000 ppm. The growth promotion effect of a root in 4-C1-IAA and TFIBA was compared with IBA for an azalea. The result showed that 4-C1-IAA is the same in the effect as IBA and that TFIBA is higher than for IBA. The growth of a vine`s terminal bud was promoted by the effect of TFIBA on root growth, and the callus occurring when IBA was treated was not formed. The rooting of a strawberry was promoted by the effect of TFIBA on root growth. The combined use of TFIBA and BA promotes the growth of a side bud and forms a multi-bud plant. However, rooting was inhibited. The callus caused by the effect of BA on root growth could be suppressed through the combined use with TFIBA. 6 refs., 7 figs., 2 tabs.

Root development during soil genesis: effects of root-root interactions, mycorrhizae, and substrate

Science.gov (United States)

Salinas, A.; Zaharescu, D. G.

2015-12-01

A major driver of soil formation is the colonization and transformation of rock by plants and associated microbiota. In turn, substrate chemical composition can also influence the capacity for plant colonization and development. In order to better define these relationships, a mesocosm study was set up to analyze the effect mycorrhizal fungi, plant density and rock have on root development, and to determine the effect of root morphology on weathering and soil formation. We hypothesized that plant-plant and plant-fungi interactions have a stronger influence on root architecture and rock weathering than the substrate composition alone. Buffalo grass (Bouteloua dactyloides) was grown in a controlled environment in columns filled with either granular granite, schist, rhyolite or basalt. Each substrate was given two different treatments, including grass-microbes and grass-microbes-mycorrhizae and incubated for 120, 240, and 480 days. Columns were then extracted and analyzed for root morphology, fine fraction, and pore water major element content. Preliminary results showed that plants produced more biomass in rhyolite, followed by schist, basalt, and granite, indicating that substrate composition is an important driver of root development. In support of our hypothesis, mycorrhizae was a strong driver of root development by stimulating length growth, biomass production, and branching. However, average root length and branching also appeared to decrease in response to high plant density, though this trend was only present among roots with mycorrhizal fungi. Interestingly, fine fraction production was negatively correlated with average root thickness and volume. There is also slight evidence indicating that fine fraction production is more related to substrate composition than root morphology, though this data needs to be further analyzed. Our hope is that the results of this study can one day be applied to agricultural research in order to promote the production of crops

An Elongated Leading Edge Facilitates Rotation Flap Closure: In Vivo Demonstration.

Science.gov (United States)

Lichon, Vanessa; Barbosa, Naiara; Gomez, Doug; Goldman, Glenn

2016-01-01

Variation in the design of a rotation flap may affect wound closure tension. Lengthening the leading edge of a rotation flap has been a method of reducing the tension of closure in the primary motion. An in vitro study negating this tenant has been published. The authors set out to design an in vivo experiment to determine if lengthening the leading edge of a rotation flap has the effect of reducing closure tension in the primary motion of the repair. An animal study approved by Institutional Animal Care and Use Committee was undertaken in a pig model. A tension-measuring apparatus was designed using Teflon-coated wires and digital tensiometers. Rotation flaps of a standard design and with elongated leading edges were incised on the flanks of pigs under general anesthesia. Flap closure tensions were measured at points along the leading edge of the flap and in the secondary motion. Elongating the leading edge of a flap led to a statistically significant reduction in closure tension in the primary motion of the flap and at the flap tip. The secondary motion closure tensions were essentially unaffected. The authors confirm that elongating the leading edge of a standard rotation flap will reduce closure tension in the primary flap motion.

Creating a Bio-Inspired Solution to Prevent Erosion

Science.gov (United States)

Reher, R.; Martinez, A.; Cola, J.; Frost, D.

2016-12-01

Through the study of geophysical sciences, lessons can be developed which allow for the introduction of bio-inspired design and art concepts to K-5 elementary students. Students are placed into an engineering mindset in which they must apply the concepts of bio-geotechnics to observe how we can use nature to prevent and abate erosion. Problems are staged for students using realistic engineering scenarios such as erosion prevention through biomimicry and the study of anchorage characteristics of root structures in regard to stability of soil. Specifically, a lesson is introduced where students research, learn, and present information about bio-inspired designs to understand these concepts. They lean how plant roots differ in size and shape to stabilize soil. In addition, students perform a series of hands-on experiments which demonstrate how bio-cements and roots can slow erosion.

The Prediction of Yarn Elongation of Kenyan Ring-Spun Yarn using Extreme Learning Machines (ELM

Directory of Open Access Journals (Sweden)

Josphat Igadwa Mwasiagi

2017-03-01

Full Text Available The optimization of the manufacture of cotton yarns involves several processes, while the prediction of yarn quality parameters forms an important area of investigation. This research work concentrated on the prediction of cotton yarn elongation. Cotton lint and yarn samples were collected in textile factories in Kenya.The collected samples were tested under standard testing conditions. Cotton lint parameters, machine parameters and yarn elongation were used to design yarn elongation prediction models. The elongation prediction models used three network training algorithms, including backpropagation (BP, an extreme learning machine (ELM, and a hybrid of differential evolution (DE and an ELM referred to as DE-ELM. The prediction models recorded a mean squared error (mse value of 0.001 using 11, 43 and 2 neurons in the hidden layer for the BP, ELM and DE-ELM models respectively. The ELM models exhibited faster training speeds than the BP algorithms, but required more neurons in the hidden layer than other models. The DEELM hybrid algorithm was faster than the BP algorithm, but slower than the ELM algorithm.

One-step purification of E. coli elongation factor Tu

DEFF Research Database (Denmark)

Knudsen, Charlotte Rohde; Clark, Brian F. C.; Degn, B

1993-01-01

The tuf A gene, encoding the E. coli elongation factor Tu, was cloned in the pGEX gene fusion system. Upon expression EF-Tu is fused to glutathione-S-transferase serving as a purification handle with affinity for glutathione immobilised on agarose. This allows purification of EF-Tu in a one...

Co-occurrence of lumbar spondylolysis and lumbar disc herniation with lumbosacral nerve root anomaly

Science.gov (United States)

Yılmaz, Tevfik; Turan, Yahya; Gülşen, İsmail; Dalbayrak, Sedat

2014-01-01

Lumbosacral nerve root anomalies are the leading cause of lumbar surgery failures. Although co-occurrence of lumbar spondylolysis and disc herniation is common, it is very rare to observe that a nerve root anomaly accompanies these lesions. A 49-year-old male patient presented with sudden-onset right leg pain. Examinations revealed L5/S1 lumbar spondylolysis and disc herniation. At preoperative period, he was also diagnosed with lumbosacral root anomaly. Following discectomy and root decompression, stabilization was performed. The complaints of the patient diagnosed with lumbosacral root anomaly at intraoperative period were improved at postoperative period. It should be remembered that in patients with lumbar disc herniation and spondylolysis, lumbar root anomalies may coexist when clinical and neurological picture is severe. Preoperative and perioperative assessments should be made meticulously to prevent neurological injury. PMID:25210343

Co-occurrence of lumbar spondylolysis and lumbar disc herniation with lumbosacral nerve root anomaly

Directory of Open Access Journals (Sweden)

Tevfik Yilmaz

2014-01-01

Full Text Available Lumbosacral nerve root anomalies are the leading cause of lumbar surgery failures. Although co-occurrence of lumbar spondylolysis and disc herniation is common, it is very rare to observe that a nerve root anomaly accompanies these lesions. A 49-year-old male patient presented with sudden-onset right leg pain. Examinations revealed L5/S1 lumbar spondylolysis and disc herniation. At preoperative period, he was also diagnosed with lumbosacral root anomaly. Following discectomy and root decompression, stabilization was performed. The complaints of the patient diagnosed with lumbosacral root anomaly at intraoperative period were improved at postoperative period. It should be remembered that in patients with lumbar disc herniation and spondylolysis, lumbar root anomalies may coexist when clinical and neurological picture is severe. Preoperative and perioperative assessments should be made meticulously to prevent neurological injury.

Rooting gene trees without outgroups: EP rooting.

Science.gov (United States)

Sinsheimer, Janet S; Little, Roderick J A; Lake, James A

2012-01-01

Gene sequences are routinely used to determine the topologies of unrooted phylogenetic trees, but many of the most important questions in evolution require knowing both the topologies and the roots of trees. However, general algorithms for calculating rooted trees from gene and genomic sequences in the absence of gene paralogs are few. Using the principles of evolutionary parsimony (EP) (Lake JA. 1987a. A rate-independent technique for analysis of nucleic acid sequences: evolutionary parsimony. Mol Biol Evol. 4:167-181) and its extensions (Cavender, J. 1989. Mechanized derivation of linear invariants. Mol Biol Evol. 6:301-316; Nguyen T, Speed TP. 1992. A derivation of all linear invariants for a nonbalanced transversion model. J Mol Evol. 35:60-76), we explicitly enumerate all linear invariants that solely contain rooting information and derive algorithms for rooting gene trees directly from gene and genomic sequences. These new EP linear rooting invariants allow one to determine rooted trees, even in the complete absence of outgroups and gene paralogs. EP rooting invariants are explicitly derived for three taxon trees, and rules for their extension to four or more taxa are provided. The method is demonstrated using 18S ribosomal DNA to illustrate how the new animal phylogeny (Aguinaldo AMA et al. 1997. Evidence for a clade of nematodes, arthropods, and other moulting animals. Nature 387:489-493; Lake JA. 1990. Origin of the metazoa. Proc Natl Acad Sci USA 87:763-766) may be rooted directly from sequences, even when they are short and paralogs are unavailable. These results are consistent with the current root (Philippe H et al. 2011. Acoelomorph flatworms are deuterostomes related to Xenoturbella. Nature 470:255-260).

Venus Elongation Measurements for the Transit of Venus, using the ...

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 9; Issue 11. Venus Elongation Measurements for the Transit of Venus, using the Historical Jantar Mantar Observatory. N Rathnasree. Classroom Volume 9 Issue 11 November 2004 pp 46-55 ...

Resistance of red clover (Trifolium pratense) to the root parasitic plant Orobanche minor is activated by salicylate but not by jasmonate.

Science.gov (United States)

Kusumoto, Dai; Goldwasser, Yaakov; Xie, Xiaonan; Yoneyama, Kaori; Takeuchi, Yasutomo; Yoneyama, Koichi

2007-09-01

Obligate root holoparasites of the genus Orobanche attack dicotyledonous crops and cause severe losses in many parts of the world. Chemical induction of plant defence systems such as systemic acquired resistance was proposed to be an available strategy to control the root parasite, but the detailed mechanisms involved have not been clarified. The aim of this study was to elucidate the effects of salicylic acid (SA), jasmonic acid (JA) and their analogues on resistance of red clover to Orobanche parasitism. Roots of red clover grown in plastic chambers were applied with SA, S-methyl benzo[1,2,3]thiadiazole-7-carbothioate (BTH), methyl jasmonate (MeJA) and n-propyl dihydrojasmonate (PDJ), and then were inoculated with O. minor seeds. Attachments of the parasite were observed after 5 weeks. SA and BTH, inducers of SA-mediated defences, significantly reduced the number of established parasites by more than 75 %. By contrast, MeJA and PDJ, inducers of JA-mediated defences, did not affect parasitism. The reduction in the number of established parasites by SA and BTH was due to the inhibited elongation of O. minor radicles and the activation of defence responses in the host root including lignification of the endodermis. These results suggest that SA-induced resistance, but not JA-induced resistance, is effective in inhibiting Orobanche parasitism and that the resistance is expressed by the host root both externally and internally.

Assessment of root surfaces of apicected teeth: A scanning electron ...

African Journals Online (AJOL)

2014-05-15

May 15, 2014 ... exposed dentinal tubules, which may prevent the leakage ... stored in sterile distilled water at 37°C. Teeth with intact roots and mature apexes ..... 29. von Arx T, Kunz R, Schneider AC, Burgin W, Lussi A. Detection of dentinal.

Development and evaluation of two root caries controlling programmes for home-based frail people older than 75 years

DEFF Research Database (Denmark)

Ekstrand, Kim; Martignon, Stefania; Holm-Pedersen, Poul

2008-01-01

(i) Initially, to devise and examine the validity of a system for determining lesion activity on root surfaces, and (ii) compare the effectiveness of two preventive programmes in controlling root caries in elderly people using the devised system....

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