The surface characteristics of pedal mucus: a potential aid to the settlement of marine organisms?

2002 ◽  
Vol 82 (1) ◽  
pp. 131-139 ◽  
Author(s):  
Sebastian P. Holmes ◽  
Andrew Cherrill ◽  
Mark S. Davies
Keyword(s):  
Size Range ◽  
Surface Characteristics ◽  
Marine Organisms ◽  
Littorina Littorea ◽  
Patella Vulgata ◽  
Settlement Site ◽  
Silicon Grease

Surface characteristics including wettability, thickness and adhesive potential of the pedal mucus produced by Patella vulgata and Littorina littorea were measured, to determine their effects on the settlement of marine organisms. The pedal mucus produced by P. vulgata was less wettable than that produced by L. littorea. For organisms that prefer to settle on hydrophobic substrata the pedal mucus produced by P. vulgata would be their preferred settlement site. The pedal mucus produced by stationary P. vulgata was thicker (mean thickness±SE=0·37±0·004 mm) than the pedal mucus produced by mobile P. vulgata and/or that produced by L. littorea, neither of which differed in their thickness (mean thickness±SE =0·10±0·01 mm).  The pedal mucus produced by P. vulgata had a greater adhesive potential (mean force of adhesion for the size range of mimics examined=3715–5380 Nm2) than the pedal mucus produced by L. littorea (mean force of adhesion for the size range of mimics examined=2846–3361 Nm2). Comparison of the adhesive potential of the pedal mucuses with a pedal mucus analogue, silicon grease, suggests that the pedal mucuses function as a Stefan (1874) adhesive when adhering organisms.

The effect of pedal mucus on barnacle cyprid settlement: a source for indirect interactions in the rocky intertidal?

2002 ◽  
Vol 82 (1) ◽  
pp. 117-129 ◽  
Author(s):  
Sebastian P. Holmes
Keyword(s):  
Positive Feedback ◽  
Field Experiments ◽  
Distribution Patterns ◽  
Marine Organisms ◽  
Rocky Intertidal ◽  
Exploratory Behaviour ◽  
Littorina Littorea ◽  
Laboratory Assessment ◽  
Physical Entrapment ◽  
Silicon Grease

Laboratory assessment of barnacle cyprid settlement showed that it was increased by a multiple of ∼6 and by a multiple of ∼3 by the pedal mucus produced by Patella vulgata and by Littorina littorea, respectively. Field experiments showed that pedal mucus produced by P. vulgata could increase cyprid settlement by a multiple of ∼4, but that there was no effect of the pedal mucus produced by L. littorea. Evaluation of the effect of pedal mucus coated with nitro-cellulose and various pedal extracts, on cyprid settlement, ascertained that there appeared to be no chemotactic or chemotaxic effect of pedal mucus on cyprid settlement. In contrast, the use of a physical analogue to pedal mucus, silicon grease, increased cyprid settlement by a multiple of ∼18.  Pedal mucus produced by P. vulgata and by L. littorea increased the time spent by cyprids in surface suitability testing by a multiple of ∼10 and ∼3, respectively. Only the pedal mucus produced by P. vulgata had any effect on the exploratory behaviour of cyprids increasing the time spent on this behaviour by a multiple of ∼3. Pedal mucus affects the settlement of cyprids through adhesive enmeshment, resulting in positive feedback to the mechanoreceptors housed in the antennules of cyprids, in what is effectively a settlement cascade. Pedal mucus produced by P. vulgata and L. littorea can affect the settlement of the majority of settling marine organisms through physical entrapment. Pedal mucus produced by L. littorea will have little, if any, effect on the settlement of organisms in the field whereas the pedal mucus produced by P. vulgata may be of major importance in determining the adult distribution patterns.

Effect of Addition of Nano Zirconia in Ceramic Glazes

2014 ◽  
Vol 984-985 ◽  
pp. 488-494 ◽  
Author(s):  
G. Venkatesh ◽  
Deivarajan Thenmuhil ◽  
S. Manisha Vidyavathy ◽  
R. Vinothan
Keyword(s):  
Particle Size ◽  
Single Phase ◽  
Size Range ◽  
Ceramic Body ◽  
Sol Gel ◽  
Surface Characteristics ◽  
Morphological Characterization ◽  
Good Resistance ◽  
Chemical Attack ◽  
Nanometric Size

In this present study zirconia particles of nanometric dimensions were synthesized using sol-gel method via the starting precursors of zirconium oxy-chloride octa-hydrate (ZrOCl2.8H2O) and oxalic acid {(COOH)2.2H2O}. A transparent sol obtained was dried at 110° C for 12 hours and the dried gel was subjected to calcination at 1000°C respectively for 3 hours in order to obtain nanozirconia particles. XRD characterization reveals the presence of single phase tetragonal ZrO2and SEM morphological characterization reveals the presence of nanosize ZrO2particles .The particle size distribution also confirms the nanometric size range of ZrO2particles. The obtained nanoparticles was incorporated in the glaze composition which generally is defined as a thin glassy layer on a ceramic body that results by applying a special admixture on ceramic body and by fusing at high temperature. This glaze formulation is well bounded for dry tile manufacturing process .The incorporation of the prepared nanozirconia in a typical glaze composition are well established for its excellent mechanical, thermal and good resistance to chemical attack. Addition of zirconia increases the opacity of the tiles and also enhances the brightness .In this study with the comparison of standard conventional zircon it is bound to say that particle size decreases. Moreover glaze characterizations i.e.TG-DTA, Spectrophotometer, Abrasion resistance, crazing resistance tests was studied which shows the improvement of surface characteristics which has been enhanced by using the nanoparticles. The opacity is also increased with lower dose of usage of zirconia nanoparticles.

Steroid sulphatase, arylsulphatase and β-glucuronidase in marine invertebrates

1960 ◽  
Vol 39 (1) ◽  
pp. 51-61 ◽  
Author(s):  
E. D. S. Corner ◽  
Y. A. Leon ◽  
R. D. Bulbrook
Keyword(s):  
Marine Invertebrates ◽  
Littorina Littorea ◽  
Optimum Conditions ◽  
Widespread Occurrence ◽  
Marine Molluscs ◽  
Patella Vulgata ◽  
Steroid Sulphatase ◽  
Glucuronidase Activity ◽  
Digestive Glands

The widespread occurrence of sulphatases in the Mollusca was first demonstrated by Soda & Hattori (1933 a, b) who showed that these enzymes are mainly concentrated in the digestive glands. That extracts from marine molluscs also possess β-glucuronidase activity was first noted by Dodgson, Lewis & Spencer (1952) who studied the optimum conditions for the activity of this enzyme and arylsulphatase in Patella vulgata (L.) and Littorina littorea (L.) and applied their findings in an investigation of the distribution of both enzymes among various other marine molluscs (Dodgson, Lewis & Spencer, 1953).

The Biological Accumulation and Monitoring of Chemical Wastes in Arctic Waters

1986 ◽  
Vol 18 (2) ◽  
pp. 1-11 ◽  
Author(s):  
E. J. Perkins
Keyword(s):  
Trace Element ◽  
Comparative Studies ◽  
Decapod Crustacean ◽  
Important Influence ◽  
The Arctic ◽  
Littorina Littorea ◽  
General Application ◽  
Patella Vulgata ◽  
Pagurus Bernhardus ◽  
Chemical Wastes

The biological accumulation and monitoring of chemical wastes are considered with particular reference to the Solway Firth, U.K. Monitoring of the influence of chemical wastes may be concerned with somatic or reproductive responses and is more usually the former. It is shown that size and abundance are not an indication of a species fertility which is crucial to its conservation. Diet has an important influence upon the magnitude of the trace element burden of gastropod molluscs and it is shown that the fertility of Patella vulgata and Littorina littorea is unaffected by marked increases in the trace element burden. In this study, some of the species examined viz., the polychaete worms Phyllodoce maculata and Scoloplos armiger, the decapod crustacean Pagurus bernhardus and the gastropod molluscs, Littorina littorea and Thais lapillus, have a distribution which extends into arctic waters. Clearly such animals offer the opportunity for comparative studies to test the more general application of the work reported. Such comparative work would also facilitate efforts to apply data from the boreal region to problems in the Arctic.

Microtomy of spherical Al2O3 powders

1983 ◽  
Vol 41 ◽  
pp. 74-75
Author(s):  
E.J. Jenkins ◽  
D.S. Tucker ◽  
J.J. Hren
Keyword(s):  
Thin Film ◽  
Size Range ◽  
Particle Aggregation ◽  
Ion Milling ◽  
Thin Sections ◽  
Α Phase ◽  
Convenient Means ◽  
Van Der Waals Attraction ◽  
Negative Feature ◽  
Film Substrate

The size range of mineral and ceramic particles of one to a few microns is awkward to prepare for examination by TEM. Electrons can be transmitted through smaller particles directly and larger particles can be thinned by crushing and dispersion onto a substrate or by embedding in a film followed by ion milling. Attempts at dispersion onto a thin film substrate often result in particle aggregation by van der Waals attraction. In the present work we studied 1-10 μm diameter Al2O3 spheres which were transformed from the amprphous state to the stable α phase.After the appropriate heat treatment, the spherical powders were embedded in as high a density as practicable in a hard EPON, and then microtomed into thin sections. There are several advantages to this method. Obviously, this is a rapid and convenient means to study the microstructure of serial slices. EDS, ELS, and diffraction studies are also considerably more informative. Furthermore, confidence in sampling reliability is considerably enhanced. The major negative feature is some distortion of the microstructure inherent to the microtoming operation; however, this appears to have been surprisingly small. The details of the method and some typical results follow.

Microdiffraction Patterns of Small Metallic Particles II; Theoretical Analysis

1982 ◽  
Vol 40 ◽  
pp. 668-669
Author(s):  
A. Gómez ◽  
P. Schabes-Retchkiman ◽  
M. José-Yacamán ◽  
T. Ocaña
Keyword(s):  
Experimental Data ◽  
Electron Diffraction ◽  
Theoretical Analysis ◽  
Size Range ◽  
Dynamical Theory ◽  
Metallic Particles ◽  
Splitting Effect

The splitting effect that is observed in microdiffraction pat-terns of small metallic particles in the size range 50-500 Å can be understood using the dynamical theory of electron diffraction for the case of a crystal containing a finite wedge. For the experimental data we refer to part I of this work in these proceedings.

Electron Microscopy of the Shape of Small Metal Particles

1977 ◽  
Vol 35 ◽  
pp. 300-301
Author(s):  
M. Jose Yacaman
Keyword(s):  
Electron Microscopy ◽  
Metal Particle ◽  
Field Experiments ◽  
Size Range ◽  
Dark Field ◽  
Metal Particles ◽  
Bragg Condition ◽  
Crystal Particle ◽  
Small Metal Particle ◽  
Small Metal Particles

In the Study of small metal particles the shape is a very Important parameter. Using electron microscopy Ino and Owaga(l) have studied the shape of twinned particles of gold. In that work electron diffraction and contrast (dark field) experiments were used to produce models of a crystal particle. In this work we report a method which can give direct information about the shape of an small metal particle in the amstrong- size range with high resolution. The diffraction pattern of a sample containing small metal particles contains in general several systematic and non- systematic reflections and a two-beam condition can not be used in practice. However a N-beam condition produces a reduced extinction distance. On the other hand if a beam is out of the bragg condition the effective extinction distance is even more reduced.

Freeze-dried dispersions for automated SEM analysis of individual submicron airborne particulates

1992 ◽  
Vol 50 (1) ◽  
pp. 408-409
Author(s):  
Karen A. Katrinak ◽  
David W. Brekke ◽  
John P. Hurley
Keyword(s):  
Air Pollutants ◽  
Size Range ◽  
Sem Analysis ◽  
Individual Particle ◽  
Chemical Data ◽  
Particle Analysis ◽  
Bulk Analysis ◽  
Airborne Particulates ◽  
Freeze Dried ◽  
Individual Particle Analysis

Individual-particle analysis is well established as an alternative to bulk analysis of airborne particulates. It yields size and chemical data on a particle-by-particle basis, information that is critical in predicting the behavior of air pollutants. Individual-particle analysis is especially important for particles with diameter < 1 μm, because particles in this size range have a disproportionately large effect on atmospheric visibility and health.

Electron Microscopy in the Study of Natural Phytoplankton Assemblages

1985 ◽  
Vol 43 ◽  
pp. 620-623
Author(s):  
Linda Sicko-Goad
Keyword(s):  
Electron Microscopy ◽  
Aquatic Environment ◽  
Size Range ◽  
Physical Parameters ◽  
Specific Information ◽  
Phytoplankton Assemblages ◽  
Phytoplankton Productivity ◽  
Ecosystem Effects ◽  
Time Of Year ◽  
Species Specific

Although the use of electron microscopy and its varied methodologies is not usually associated with ecological studies, the types of species specific information that can be generated by these techniques are often quite useful in predicting long-term ecosystem effects. The utility of these techniques is especially apparent when one considers both the size range of particles found in the aquatic environment and the complexity of the phytoplankton assemblages.The size range and character of organisms found in the aquatic environment are dependent upon a variety of physical parameters that include sampling depth, location, and time of year. In the winter months, all the Laurentian Great Lakes are uniformly mixed and homothermous in the range of 1.1 to 1.7°C. During this time phytoplankton productivity is quite low.

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