Role of Ecklonia radiata (C. Ag.) J. Agardh in determining trace metal availability in coastal waters. I. Total trace metals

1987 ◽  
Vol 38 (3) ◽  
pp. 307 ◽  
Author(s):  
HW Higgins ◽  
DJ Mackey
Keyword(s):  
Trace Metals ◽  
Metal Binding ◽  
Late Summer ◽  
Dry Weight ◽  
Metal Availability ◽  
Metal Binding Sites ◽  
Accumulation Of Metals ◽  
Concentration Factors

No seasonal variations were found in the concentrations of Zn, Cd, Cu, K, Ca, Mg and Na in the kelp E. radiata collected from the marine-dominated Port Hacking estuary on the east coast of Australia. Concentrations of Fe and Mn were about 60% higher in late summer. The relative distributions of all metals between different kelp tissues, however, showed no seasonal variation. Concentration factors (dry weight basis) for trace metals ranged from 2600 for Cu to 68 000 for Fe. With high biomasses common in macroalgal ecosystems, a large proportion of the non-sediment- bound trace metals can be associated with the macroalgae, which therefore act as substantial buffers for these elements. Metal concentration factors (Y, wet wt basis) were related to oceanic residence times (τ) by the equation log Y = -0.69 logτ + 5.4. The distribution of the aikaii and akaline earth metais (K, Ca, Mg and Na) was relativeiy uniform throughout the various kelp tissues. However, concentrations of Fe, Mn, Zn and Cd were significantly higher in the older extremities (holdfast and eroding tip) than in the meristematic region. Although the holdfast also had higher levels of Cu than the meristem, levels were lower in the eroding tip. The results suggest either a slow net intracellular accumulation of metals with time or an increase in potential metal- binding sites as the extremities senesce. Translocation and elimination of surplus metals through the eroding tip or holdfast was thought not to be important in E. radiata as metal concentrations did not differ between live and dead haptera of the holdfast. Likewise, storage of metals in either the holdfast or eroding tip was considered unlikely because of the constant relative tissue distribution throughout the year and lack of metal mobilization during periods of growth. Pretreatment of kelp tissue with an EDTA wash released about 90% of the total Zn and Cd, 25% of the Cu and 7% of the Fe, suggesting that a large proportion of the total kelp Zn and Cd is associated with the apparent free space (AFS). With rapid exchange between seawater and the AFS, E. radiata is therefore not generally useful as a sentinel accumulator species in pollution studies for assessing long term integrated changes of metals in the water column.

The Role of ECA in the Development of Dynamic Riser Systems

2003 ◽  
Author(s):  
Mike Campbell ◽  
Stephen Jones ◽  
Jafar Korloo
Keyword(s):  
Critical Assessment ◽  
Acceptance Criteria ◽  
Critical Flaw ◽  
Margin Of Safety ◽  
Potential Failure ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Non Destructive

An Engineering Critical Assessment (ECA) is a procedure that may be used to define and characterise critical flaw sizes from which acceptance criteria for non-destructive examination (NDE) can be developed or confirmed. Dynamic riser systems are fatigue sensitive structures that are commonly regarded as one of the most challenging aspects of a deepwater development. An ECA provides the facility to increase confidence as it develops an understanding of the margin of safety afforded by the derived acceptance criteria based upon variations in extreme and long-term loads, material properties such as fracture toughness, quality standards for welding, control of stress concentration factors and the nature of potential failure. The paper will demonstrate the objectives, adopted methodology and explore the conclusions of an ECA with the aid of examples.

Asymmetric cell division and differentiation; fern spore germination as a model. II. Ultrastructural studies

1985 ◽  
Vol 86 ◽  
pp. 227-230
Author(s):  
Alix R. Bassel
Keyword(s):  
Cell Division ◽  
Metal Binding ◽  
Asymmetric Cell Division ◽  
Red Light ◽  
Nuclear Migration ◽  
Silver Stain ◽  
Metal Binding Sites ◽  
Ultrastructural Studies ◽  
Fern Spore Germination

SynopsisThe germination of Onoclea spores is a model system with many advantages for the study of asymmetric cell division and cellular differentiation. Our results suggest that both microtubules and a lipophilic site are important in the nuclear migration to one end of the spore prior to asymmetric cell division. A metalbinding region containing pore-like structures in the proximal face of the spore coat may be a source of the inherent polarity of the spore. The pattern of endogenous metal binding during germination has been characterised using a sulphide-silver stain. Metal-binding sites are described in a differentiating system in which polarity is imposed externally using polarised red light. The possibility of a role of ion gradients in determining the direction of nuclear migration is discussed.

Similar diurnal, seasonal and annual rhythms in radial root expansion across two coexisting Mediterranean oak species

2020 ◽  
Vol 40 (7) ◽  
pp. 956-968 ◽  
Author(s):  
Josu G Alday ◽  
Jesús Julio Camarero ◽  
Jesús Revilla ◽  
Víctor Resco de Dios
Keyword(s):  
Vapor Pressure Deficit ◽  
Environmental Parameters ◽  
Late Summer ◽  
Growth Strategy ◽  
Environmental Drivers ◽  
Root Radius ◽  
Tree Roots ◽  
Quercus Faginea

Abstract Dendrometers are being increasingly used to measure stem radius changes in trees and to unravel the mechanisms underlying stem daily rhythms of radial expansion and contraction. Nevertheless, automated dendrometers have not been often used to measure root radius dynamics, their relationship with environmental variables and the influence of endogenous processes, especially in drought-prone Mediterranean areas. Here, we measured root radius dynamics of two coexisting oak species (the evergreen Quercus ilex L. and the deciduous Quercus faginea Lam). Our goals were to describe annual, seasonal and diurnal scale root radius patterns and to disentangle the role of different environmental parameters as drivers. Long-term high-resolution measurements (every 15 min over 7 years) were collected with automated point dendrometers on the main tree roots of five individuals per species. Root radius annual change patterns were bimodal and similar for both oak species. Quercus faginea Lam showed three times larger root increment in the spring than Q. ilex, but the bimodal pattern was stronger in Q. ilex, which showed a larger root increment in autumn. Quercus faginea Lam showed an earlier root phenological activation in the spring and in late summer compared with Q. ilex. The effects of environmental drivers across species were similar at daily scales: root radius increased with air temperature and soil moisture, and it decreased with rising vapor pressure deficit. Furthermore, daily root radius variations for both oak species were maintained after extracting statistically the environmental effects, which points toward a significant role of endogenous drivers. These differences in root radius change patterns at seasonal to daily scales likely result from the differences in leaf phenology and growth strategy. Quercus faginea Lam is deciduous and has a faster growing rate in spring than the evergreen Q. ilex, which can grow more in summer.

scholarly journals Intracellular trafficking of the human Wilson protein: the role of the six N-terminal metal-binding sites

2004 ◽  
Vol 380 (3) ◽  
pp. 805-813 ◽  
Author(s):  
Michael A. CATER ◽  
John FORBES ◽  
Sharon La FONTAINE ◽  
Diane COX ◽  
Julian F. B. MERCER
Keyword(s):  
Metal Binding ◽  
Binding Sites ◽  
Intracellular Trafficking ◽  
Copper Toxicity ◽  
Site Directed Mutagenesis ◽  
Metal Binding Sites ◽  
Wilson Protein ◽  
Necessary And Sufficient ◽  
Golgi Network

The Wilson protein (ATP7B) is a copper-transporting CPx-type ATPase defective in the copper toxicity disorder Wilson disease. In hepatocytes, ATP7B delivers copper to apo-ceruloplasmin and mediates the excretion of excess copper into bile. These distinct functions require the protein to localize at two different subcellular compartments. At the trans-Golgi network, ATP7B transports copper for incorporation into apo-ceruloplasmin. When intracellular copper levels are increased, ATP7B traffics to post-Golgi vesicles in close proximity to the canalicular membrane to facilitate biliary copper excretion. In the present study, we investigated the role of the six N-terminal MBSs (metal-binding sites) in the trafficking process. Using site-directed mutagenesis, we mutated or deleted various combinations of the MBSs and assessed the effect of these changes on the localization and trafficking of ATP7B. Results show that the MBSs required for trafficking are the same as those previously found essential for the copper transport function. Either MBS 5 or MBS 6 alone was sufficient to support the redistribution of ATP7B to vesicular compartments. The first three N-terminal motifs were not required for copper-dependent intracellular trafficking and could not functionally replace sites 4–6 when placed in the same sequence position. Furthermore, the N-terminal region encompassing MBSs 1–5 (amino acids 64–540) was not essential for trafficking, with only one MBS close to the membrane channel, necessary and sufficient to support trafficking. Our findings were similar to those obtained for the closely related ATP7A protein, suggesting similar mechanisms for trafficking between copper-transporting CPx-type ATPases.

scholarly journals Crystal Structures of Apo and Metal-Bound Forms of the UreE Protein fromHelicobacter pylori: Role of Multiple Metal Binding Sites,

Biochemistry ◽  
2010 ◽  
Vol 49 (33) ◽  
pp. 7080-7088 ◽  
Author(s):  
Rong Shi ◽  
Christine Munger ◽  
Abdalin Asinas ◽  
Stéphane L. Benoit ◽  
Erica Miller ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Metal Binding ◽  
Binding Sites ◽  
Metal Binding Sites

scholarly journals PENGGUNAAN MEDIA ALTERNATIVE (DIAPERS) TERHADAP PERTUMBUHAN DAN PRODUKSI TANAMAN CABAI

Jurnal Agrium ◽  
2018 ◽  
Vol 15 (1) ◽  
pp. 34
Author(s):  
Safrizal Safrizal ◽  
Nazimah Nazimah ◽  
Rina Resssi
Keyword(s):  
Dry Weight ◽  
Leaf Length ◽  
Household Waste ◽  
Home Garden ◽  
Root Weight ◽  
Plant Canopy ◽  
Number Of Leaves ◽  
Different Response

Red chili is a major vegetable both in Indonesia and abroad due to its benefits to the needs of nutrition and health through cooking spices. Utilization of home garden yard is an effective way to cultivate pepper plants. On the other hand, every household produces household waste which is difficult to decompose for instance diapers, so that it can cause environmental pollution in long-term. This study was conducted to investigate the role of planting media such as diapers of on chili growth. The results showed that the use of diapers of diapers as planting media gave no significant different to plant height at 1, 4, 7, 10, 13 and 16 week after application.  It also did not increase the number of leaves at the age of 1, 7, 10, 13 and 16 week after application.  There were no changes in leaf length at ages 1, 4, 7, 10 and 16 week after application. It also happened to also its leaf width at ages 1, 4, 7, 10, 13 and 16 week after application and number of branches at ages 1, 4, 7, 13 and 16 week after aplication. However, it showed a significant different to the number of leaves at age 4 week after planting and its leaf length at age 13 week after planting.   The interaction of using diapers as planting media gave significantly different response to root number, root length, wet root weight and plant canopy, and dry weight roots and plant canopy.

scholarly journals The Role of GMXCXXC Metal Binding Sites in the Copper-induced Redistribution of the Menkes Protein

1999 ◽  
Vol 274 (16) ◽  
pp. 11170-11177 ◽  
Author(s):  
Daniel Strausak ◽  
Sharon La Fontaine ◽  
Joanne Hill ◽  
Stephen D. Firth ◽  
Paul J. Lockhart ◽  
...  
Keyword(s):  
Metal Binding ◽  
Binding Sites ◽  
Metal Binding Sites ◽  
Menkes Protein

scholarly journals BioMetAll: Identifying Metal-Binding Sites in Proteins from Backbone Preorganization

2020 ◽  
Author(s):  
José-Emilio Sánchez-Aparicio ◽  
Laura Tiessler-Sala ◽  
Lorea Velasco-Carneros ◽  
Lorena Roldán-Martín ◽  
Giuseppe Sciortino ◽  
...  
Keyword(s):  
Metal Binding ◽  
Binding Sites ◽  
De Novo ◽  
Conformational Transition ◽  
Protein Backbone ◽  
Metal Binding Sites ◽  
Structural Match ◽  
Geometric Descriptors ◽  
Metal Migration

<div><div><div><p>With a large amount of research dedicated to decoding how metallic species bind to protein, in silico methods are interesting allies for experimental procedures. To date, computational predictors mostly work by identifying the best possible sequence or structural match of the target protein with metal binding templates. These approaches are fundamentally focused on the first coordination sphere of the metal. Here, we present the BioMetAll predictor that is based on a different postulate: the formation of a potential metal-binding site is related to the geometric organization of the protein backbone. We first report the set of convenient geometric descriptors of the backbone needed for the algorithm and their parametrization from a statistical analysis. Then, the successful benchmark of BioMetAll on a set of more than 50 metal-binding X-Ray structures is presented. Because BioMetAll allows structural predictions regardless of the exact geometry of the side chains, it appears extremely valuable for systems which structures (either experimental or theoretical) are not optimal for metal binding sites. We report here its application on three different challenging cases i) the modulation of metal-binding sites during conformational transition in human serum albumin, ii) the identification of possible routes of metal migration in hemocyanins, and iii) the prediction of mutations to generate convenient metal-binding sites for de novo biocatalysts. This study shows that BioMetAll offers a versatile platform for numerous fields of research at the interface between inorganic chemistry and biology, and allows to highlight the role of the preorganization of the protein backbone as a marker for metal binding.</p></div></div></div>

Key Morphological Events following Late-Season Goosegrass (Eleusine indica) Germination

2018 ◽  
Vol 33 (1) ◽  
pp. 196-201
Author(s):  
Robert Andrew Kerr ◽  
Lambert B. McCarty ◽  
William C. Bridges ◽  
Matthew Cutulle
Keyword(s):  
Life Cycle ◽  
Growth Parameters ◽  
Growth Curves ◽  
Late Summer ◽  
Dry Weight ◽  
Maximum Growth ◽  
Major Pest ◽  
Leaf Dry Weight ◽  
Term Management

AbstractGoosegrass is a weedy C4species throughout the world and a major pest in turfgrass systems. Further research is needed to characterize morphological events of goosegrass germinating in late summer to enhance long-term management programs. The objective of this study was to determine whether goosegrass germinating on August 15 will complete a life cycle before the first killing frost, typically November 15 in Clemson, SC. A biotype from Clemson, SC, was collected and a growth-chamber experiment was conducted to simulate autumn maximum and minimum temperatures. Culm, leaf, root, and raceme biomass measurements were recorded weekly, and growth curves were modeled. The inflection point (i.e., point of maximum growth) occurred for the following growth parameters: culm dry weight at 26.5 d after emergence (DAE), leaf dry weight at 26.6 DAE, number of racemes per plant at 50.7 DAE, raceme dry weight (including germinable seed) at 56.0 DAE, and root dry weight at 42.1 DAE. The completion of the life cycle occurred on October 22 (68 DAE), approximately 3 wk before the typical first killing frost in Clemson, SC. In summary, turf managers need to address goosegrass that germinates through approximately the first week of September at this location to avoid production of viable seed.

scholarly journals Role of Glutathione in Buffering Excess Intracellular Copper in Streptococcus pyogenes

mBio ◽  
2020 ◽  
Vol 11 (6) ◽  
Author(s):  
Louisa J. Stewart ◽  
Cheryl-lynn Y. Ong ◽  
May M. Zhang ◽  
Stephan Brouwer ◽  
Liam McIntyre ◽  
...  
Keyword(s):  
Streptococcus Pyogenes ◽  
Metal Binding ◽  
Metal Ion ◽  
Physiological Role ◽  
Metal Availability ◽  
Content Type ◽  
Bacterial Physiology ◽  
Group A

ABSTRACT Copper (Cu) is an essential metal for bacterial physiology but in excess it is bacteriotoxic. To limit Cu levels in the cytoplasm, most bacteria possess a transcriptionally responsive system for Cu export. In the Gram-positive human pathogen Streptococcus pyogenes (group A Streptococcus [GAS]), this system is encoded by the copYAZ operon. This study demonstrates that although the site of GAS infection represents a Cu-rich environment, inactivation of the copA Cu efflux gene does not reduce virulence in a mouse model of invasive disease. In vitro, Cu treatment leads to multiple observable phenotypes, including defects in growth and viability, decreased fermentation, inhibition of glyceraldehyde-3-phosphate dehydrogenase (GapA) activity, and misregulation of metal homeostasis, likely as a consequence of mismetalation of noncognate metal-binding sites by Cu. Surprisingly, the onset of these effects is delayed by ∼4 h even though expression of copZ is upregulated immediately upon exposure to Cu. Further biochemical investigations show that the onset of all phenotypes coincides with depletion of intracellular glutathione (GSH). Supplementation with extracellular GSH replenishes the intracellular pool of this thiol and suppresses all the observable effects of Cu treatment. These results indicate that GSH buffers excess intracellular Cu when the transcriptionally responsive Cu export system is overwhelmed. Thus, while the copYAZ operon is responsible for Cu homeostasis, GSH has a role in Cu tolerance and allows bacteria to maintain metabolism even in the presence of an excess of this metal ion. IMPORTANCE The control of intracellular metal availability is fundamental to bacterial physiology. In the case of copper (Cu), it has been established that rising intracellular Cu levels eventually fill the metal-sensing site of the endogenous Cu-sensing transcriptional regulator, which in turn induces transcription of a copper export pump. This response caps intracellular Cu availability below a well-defined threshold and prevents Cu toxicity. Glutathione, abundant in many bacteria, is known to bind Cu and has long been assumed to contribute to bacterial Cu handling. However, there is some ambiguity since neither its biosynthesis nor uptake is Cu-regulated. Furthermore, there is little experimental support for this physiological role of glutathione beyond measuring growth of glutathione-deficient mutants in the presence of Cu. Our work with group A Streptococcus provides new evidence that glutathione increases the threshold of intracellular Cu availability that can be tolerated by bacteria and thus advances fundamental understanding of bacterial Cu handling.

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