What is the difference in organic matrix of aragonite vs. vaterite polymorph in natural shell and pearl? Study of the pearl-forming freshwater bivalve mollusc Hyriopsis cumingii

2013 ◽  
Vol 33 (3) ◽  
pp. 1521-1529 ◽  
Author(s):  
Yufei Ma ◽  
Sophie Berland ◽  
Jean-Pierre Andrieu ◽  
Qingling Feng ◽  
Laurent Bédouet
Keyword(s):  
Organic Matrix ◽  
Bivalve Mollusc ◽  
Freshwater Bivalve ◽  
Hyriopsis Cumingii ◽  
The Difference

Comparison of the isotopic composition of fish otolith-bound organic N with host tissue

2020 ◽  
Vol 77 (2) ◽  
pp. 264-275
Author(s):  
Jessica A. Lueders-Dumont ◽  
Daniel M. Sigman ◽  
Beverly J. Johnson ◽  
Olaf P. Jensen ◽  
Sergey Oleynik ◽  
...  
Keyword(s):  
Isotope Analysis ◽  
Organic Matrix ◽  
Fish Tissue ◽  
Organic N ◽  
Total N ◽  
Highly Sensitive ◽  
The Difference ◽  
Ground Truthing ◽  
Highly Correlated ◽  
Native Organic Matter

The15N/14N ratio of the fish-native organic matter preserved in fish otoliths (or δ15Noto) may allow for reconstruction of fish trophic history and changes in food webs. To support this application, ground-truthing data are needed on the relationships among the δ15N of diet, of fish tissue (e.g., white muscle tissue, δ15Nwmt), and δ15Noto. Using a highly sensitive method for N isotope analysis, δ15Notowas compared with δ15Nwmtin 24 teleost species. Within a species, the difference between δ15Notoand δ15Nwmt(Δδ15No-w) varied little across individuals, confirming the utility of δ15Nototo reconstruct δ15Nwmtchanges for a given species. Across species, δ15Notoand δ15Nwmtwere highly correlated. However, Δδ15No-wvaried systematically across species. Phylogeny, the concentrations of total N and amino acids, and life history were ruled out as the main cause for the observed variation in Δδ15No-w. δ15Notowas lowest relative to δ15Nwmtin species producing larger otoliths. We propose that δ15Notois elevated by isotopically fractionating metabolism of the organic matrix, which is less important when otolith growth is fast and thus when the otolith is large.

scholarly journals Experimental Study on Planting Soil Preparation by Improving River & Lake Silt with Plant Wastes

2021 ◽  
Author(s):  
Haibo Chen ◽  
Zhiqiang Wu ◽  
Kai Xu ◽  
Jie Ren ◽  
Zhong Wang ◽  
...  
Keyword(s):  
Experimental Study ◽  
Plant Growth ◽  
Organic Matrix ◽  
Loess Soil ◽  
Wood Chips ◽  
Experiment Study ◽  
Fertility Index ◽  
High Nutrient ◽  
Soil Preparation ◽  
The Difference

The physicochemical properties of river & lake silt are complex, and whether it can be directly used as planting soil is worth studying. The calliopsis pot experiment is carried out with planting soil prepared by amendment material, i.e. the organic matrix which is made by fermentation of high-nutrient sludge of a river in Nanjing, the dry excavating sludge in a lake and its flocculated and dewatered sludge together with plant wastes such as wood chips, to study the effects of different types of amendment materials and compounding ratio on plant growth. The results showed that the basic properties and fertility index of the planting soil could be adjusted directionally by adding wood chips or matrix. The overall growth of calliopsis in the planting soil formed by the high-nutrient silt in a river and its compound is the best, but some of the fertility indexes of the planting soil are too high and need to be further adjusted before use; the growth of calliopsis in the improved soil made of dry-excavation silt in a lake is better than that in the original silt, such situation is positively correlated with the amount of improved materials mixed; the difference between the growth of calliopsis in the flocculated silt in a lake and that in its improved planting soil is not significant, but some of the fertility indexes are higher than the standard indexes, and such silt can be slightly adjusted and improved into the planting soil. The field cultivation experiment study of calliopsis is carried out with the dry-excavation silt in a lake mixed with 4% wood chips and the original loess soil in the experimental field, and the growth of calliopsis planted in the dry-excavation silt in a lake is better compared with that of calliopsis planted in original loess soil. The research results can provide ideas and basis for the study on improving river & lake silt into planting soil with plant wastes.

The Origin of the Moon

1962 ◽  
Vol 14 ◽  
pp. 149-155 ◽  
Author(s):  
E. L. Ruskol
Keyword(s):  
Chemical Composition ◽  
Solar System ◽  
The Moon ◽  
The Earth ◽  
The Difference ◽  
Origin Of The Moon

The difference between average densities of the Moon and Earth was interpreted in the preceding report by Professor H. Urey as indicating a difference in their chemical composition. Therefore, Urey assumes the Moon's formation to have taken place far away from the Earth, under conditions differing substantially from the conditions of Earth's formation. In such a case, the Earth should have captured the Moon. As is admitted by Professor Urey himself, such a capture is a very improbable event. In addition, an assumption that the “lunar” dimensions were representative of protoplanetary bodies in the entire solar system encounters great difficulties.

Influence of Cell Wall Composition on the Fossilisation of Bacteria and the Implications for the Search for Early Life Forms

1997 ◽  
Vol 161 ◽  
pp. 491-504 ◽  
Author(s):  
Frances Westall
Keyword(s):  
Cell Wall ◽  
Life Forms ◽  
Cation Binding ◽  
Positive Bacterium ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Transmission Electron ◽  
Hydrothermal Sediments ◽  
Identification Of Bacteria ◽  
The Difference

AbstractThe oldest cell-like structures on Earth are preserved in silicified lagoonal, shallow sea or hydrothermal sediments, such as some Archean formations in Western Australia and South Africa. Previous studies concentrated on the search for organic fossils in Archean rocks. Observations of silicified bacteria (as silica minerals) are scarce for both the Precambrian and the Phanerozoic, but reports of mineral bacteria finds, in general, are increasing. The problems associated with the identification of authentic fossil bacteria and, if possible, closer identification of bacteria type can, in part, be overcome by experimental fossilisation studies. These have shown that not all bacteria fossilise in the same way and, indeed, some seem to be very resistent to fossilisation. This paper deals with a transmission electron microscope investigation of the silicification of four species of bacteria commonly found in the environment. The Gram positiveBacillus laterosporusand its spore produced a robust, durable crust upon silicification, whereas the Gram negativePseudomonas fluorescens, Ps. vesicularis, andPs. acidovoranspresented delicately preserved walls. The greater amount of peptidoglycan, containing abundant metal cation binding sites, in the cell wall of the Gram positive bacterium, probably accounts for the difference in the mode of fossilisation. The Gram positive bacteria are, therefore, probably most likely to be preserved in the terrestrial and extraterrestrial rock record.

Structuring, Motions and Shapes of Corona Emission Line Profiles

1994 ◽  
Vol 144 ◽  
pp. 421-426
Author(s):  
N. F. Tyagun
Keyword(s):  
Emission Line ◽  
Filling Factor ◽  
Direct Relationship ◽  
Coronal Plasma ◽  
Line Of Sight ◽  
Line Profiles ◽  
The Difference ◽  
Yellow Line ◽  
Red Line

AbstractThe interrelationship of half-widths and intensities for the red, green and yellow lines is considered. This is a direct relationship for the green and yellow line and an inverse one for the red line. The difference in the relationships of half-widths and intensities for different lines appears to be due to substantially dissimilar structuring and to a set of line-of-sight motions in ”hot“ and ”cold“ corona regions.When diagnosing the coronal plasma, one cannot neglect the filling factor - each line has such a factor of its own.

Difference Fourier Analysis of Glucose Embedded and Frozen Hydrated Purple Membrane

1982 ◽  
Vol 40 ◽  
pp. 74-75
Author(s):  
Jules S. Jaffe ◽  
Robert M. Glaeser
Keyword(s):  
Purple Membrane ◽  
Data Set ◽  
High Resolution Data ◽  
X Ray ◽  
X Ray Crystallography ◽  
Fourier Techniques ◽  
Versus Protein ◽  
The Difference ◽  
Difference Fourier ◽  
Ideal Method

Although difference Fourier techniques are standard in X-ray crystallography it has only been very recently that electron crystallographers have been able to take advantage of this method. We have combined a high resolution data set for frozen glucose embedded Purple Membrane (PM) with a data set collected from PM prepared in the frozen hydrated state in order to visualize any differences in structure due to the different methods of preparation. The increased contrast between protein-ice versus protein-glucose may prove to be an advantage of the frozen hydrated technique for visualizing those parts of bacteriorhodopsin that are embedded in glucose. In addition, surface groups of the protein may be disordered in glucose and ordered in the frozen state. The sensitivity of the difference Fourier technique to small changes in structure provides an ideal method for testing this hypothesis.

Destruction of Actin Filaments by Osmium Tetroxide

1977 ◽  
Vol 35 ◽  
pp. 466-467
Author(s):  
P. Maupin-Szamier ◽  
T. D. Pollard
Keyword(s):  
Actin Filaments ◽  
Time Course ◽  
Osmium Tetroxide ◽  
Rabbit Muscle ◽  
Muscle Actin ◽  
Sodium Phosphate Buffer ◽  
Transmission Electron ◽  
The Difference ◽  
Rates Of Decay ◽  
Short Time

We have studied the destruction of rabbit muscle actin filaments by osmium tetroxide (OSO4) to develop methods which will preserve the structure of actin filaments during preparation for transmission electron microscopy.Negatively stained F-actin, which appears as smooth, gently curved filaments in control samples (Fig. 1a), acquire an angular, distorted profile and break into progressively shorter pieces after exposure to OSO4 (Fig. 1b,c). We followed the time course of the reaction with viscometry since it is a simple, quantitative method to assess filament integrity. The difference in rates of decay in viscosity of polymerized actin solutions after the addition of four concentrations of OSO4 is illustrated in Fig. 2. Viscometry indicated that the rate of actin filament destruction is also dependent upon temperature, buffer type, buffer concentration, and pH, and requires the continued presence of OSO4. The conditions most favorable to filament preservation are fixation in a low concentration of OSO4 for a short time at 0°C in 100mM sodium phosphate buffer, pH 6.0.

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