THE RELATION OF IONS TO CONTRACTILE PROCESSES. —I. THE ACTION OF SALT SOLUTIONS ON THE CILIATED EPITHELIUM OF MYTILUS EDULIS

1906 ◽  
Vol 17 (1) ◽  
pp. 89-141 ◽  
Author(s):  
Ralph S. Lillie

In 1906 R. S. Lillie (7) published an account of the effects of various pure sodium salts upon the ciliated epithelium of Mytilus edulis . He found that the ions could be arranged in the following order of “toxicity,” Cl' <NO 3 ' < Br' < I' <SCN'. Lillie also referred to the effect which various anions have upon the amount of water taken up by the cells from their external medium, and arranged the ions in the following order of efficiency in causing an absorption of water by the cells. CH 3 COO' < Cl' < NO 3 ' < C10 3 ' < Br' < I' < SCN' < BrO 3 ' < OH'.


Author(s):  
William F. Tivol ◽  
Murray Vernon King ◽  
D. F. Parsons

Feasibility of isomorphous substitution in electron diffraction is supported by a calculation of the mean alteration of the electron-diffraction structure factors for hemoglobin crystals caused by substituting two mercury atoms per molecule, following Green, Ingram & Perutz, but with allowance for the proportionality of f to Z3/4 for electron diffraction. This yields a mean net change in F of 12.5%, as contrasted with 22.8% for x-ray diffraction.Use of the hydration chamber in electron diffraction opens prospects for examining many proteins that yield only very thin crystals not suitable for x-ray diffraction. Examination in the wet state avoids treatments that could cause translocation of the heavy-atom labels or distortion of the crystal. Combined with low-fluence techniques, it enables study of the protein in a state as close to native as possible.We have undertaken a study of crystals of rat hemoglobin by electron diffraction in the wet state. Rat hemoglobin offers a certain advantage for hydration-chamber work over other hemoglobins in that it can be crystallized from distilled water instead of salt solutions.


Author(s):  
P. Echlin ◽  
M. McKoon ◽  
E.S. Taylor ◽  
C.E. Thomas ◽  
K.L. Maloney ◽  
...  

Although sections of frozen salt solutions have been used as standards for x-ray microanalysis, such solutions are less useful when analysed in the bulk form. They are poor thermal and electrical conductors and severe phase separation occurs during the cooling process. Following a suggestion by Whitecross et al we have made up a series of salt solutions containing a small amount of graphite to improve the sample conductivity. In addition, we have incorporated a polymer to ensure the formation of microcrystalline ice and a consequent homogenity of salt dispersion within the frozen matrix. The mixtures have been used to standardize the analytical procedures applied to frozen hydrated bulk specimens based on the peak/background analytical method and to measure the absolute concentration of elements in developing roots.


Author(s):  
Anthony A. Paparo ◽  
Judith A. Murphy

The purpose of this study was to localize the red neuronal pigment in Mytilus edulis and examine its role in the control of lateral ciliary activity in the gill. The visceral ganglia (Vg) in the central nervous system show an over al red pigmentation. Most red pigments examined in squash preps and cryostat sec tions were localized in the neuronal cell bodies and proximal axon regions. Unstained cryostat sections showed highly localized patches of this pigment scattered throughout the cells in the form of dense granular masses about 5-7 um in diameter, with the individual granules ranging from 0.6-1.3 um in diame ter. Tissue stained with Gomori's method for Fe showed bright blue granular masses of about the same size and structure as previously seen in unstained cryostat sections.Thick section microanalysis (Fig.l) confirmed both the localization and presence of Fe in the nerve cell. These nerve cells of the Vg share with other pigmented photosensitive cells the common cytostructural feature of localization of absorbing molecules in intracellular organelles where they are tightly ordered in fine substructures.


2020 ◽  
Vol 644 ◽  
pp. 91-103
Author(s):  
D Bearham ◽  
MA Vanderklift ◽  
RA Downie ◽  
DP Thomson ◽  
LA Clementson

Benthic suspension feeders, such as bivalves, potentially have several different food sources, including plankton and resuspended detritus of benthic origin. We hypothesised that suspension feeders are likely to feed on detritus if it is present. This inference would be further strengthened if there was a correlation between δ13C of suspension feeder tissue and δ13C of particulate organic matter (POM). Since detritus is characterised by high particulate organic matter (POC):chl a ratios, we would also predict a positive correlation between POM δ13C and POC:chl a. We hypothesised that increasing depth and greater distance from shore would produce a greater nutritional reliance by experimentally transplanted blue mussels Mytilus edulis on plankton rather than macrophyte-derived detritus. After deployments of 3 mo duration in 2 different years at depths from 3 to 40 m, M. edulis sizes were positively correlated with POM concentrations. POC:chl a ratios and δ13C of POM and M. edulis gill tissue decreased with increasing depth (and greater distance from shore). δ13C of POM was correlated with δ13C of M. edulis. Our results suggest that detritus comprised a large proportion of POM at shallow depths (<15 m), that M. edulis ingested and assimilated carbon in proportion to its availability in POM, and that growth of M. edulis was higher where detritus was present and POM concentrations were higher.


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