VARIATIONS IN THE WATER AND MINERAL CONTENTS OF SOME ORGANS OF THE SNAIL, HELIX POMATIA L.

1965 ◽  
Vol 43 (5) ◽  
pp. 771-779 ◽  
Author(s):  
R. F. Burton
Keyword(s):  
Water Content ◽  
Digestive Gland ◽  
Helix Pomatia ◽  
Dry Weight ◽  
Potassium Content ◽  
Mineral Contents ◽  
Albumen Gland ◽  
Snail Helix Pomatia

The water content of the digestive gland, foot, albumen gland, and dart sac of Helix pomatia tends to vary inversely with the concentration of sodium in the blood. That of the albumen gland depends also on size, for, having achieved a dry weight of 0.013 g, the gland continues its growth by the addition of a component containing only about 57% water. This stage is reached when the dry weight of the rest of the snail, less its shell, is about 1.2–1.8 g. The dart sac contains much more potassium than sodium or magnesium and the concentrations of potassium and of magnesium vary inversely with the amount of water in which they are dissolved. The columellar muscle resembles the dart sac in its potassium content (per kilogram dry weight) but contains more water and sodium.

VARIATIONS IN THE VOLUME AND CONCENTRATION OF THE BLOOD OF THE SNAIL, HELIX POMATIA L., IN RELATION TO THE WATER CONTENT OF THE BODY

1964 ◽  
Vol 42 (6) ◽  
pp. 1085-1097 ◽  
Author(s):  
R. F. Burton
Keyword(s):  
Water Content ◽  
Blood Volume ◽  
Total Body Water ◽  
Helix Pomatia ◽  
Dry Weight ◽  
Sodium Concentration ◽  
The Body ◽  
Albumen Gland ◽  
Snail Helix Pomatia ◽  
Total Body

A convenient measure of the "size" of a snail is its dry weight, exclusive of shell and albumen gland, and, where calculable, its blood solutes. The specimens of Helix pomatia studied contained between 3.8 and 10.2 g of Water per gram dry weight and between 51 and 456 mg of copper per kilogram dry weight. When "copper space" was defined as the weight of blood water that would contain the amount of copper present in the body, copper spaces varied between 1.1 and 4.4 g of water per gram dry weight. Variations in copper space (approximately equal to blood volume) accounted for the greater part of the variation in total body water, though the amount of water in the tissues was also variable. The concentration of sodium in the blood varied naturally over the range 46–129 mmole/kg of water, varying proportionately with chloride. Variations in sodium concentration are largely due to variations in the volume of blood in which the sodium is dissolved, but a given change in blood volume is, in general, associated with a proportionately smaller change in sodium concentration.

The Histochemical Localization of β-Glucuronidase in the Digestive Gland of the Roman Snail (Helix pomatia)

1955 ◽  
Vol s3-96 (33) ◽  
pp. 35-48
Author(s):  
F. BILLETT ◽  
S. M. McGEE-RUSSELL
Keyword(s):  
Prussian Blue ◽  
Digestive Gland ◽  
Secretory Granules ◽  
Helix Pomatia ◽  
Histochemical Localization ◽  
Enzymic Hydrolysis ◽  
Histochemical Technique ◽  
Original Technique ◽  
Snail Helix Pomatia ◽  
Hydrolysis Of

A modification of the histochemical technique for the localization of β-glucuronidase originally suggested by Friedenwald and Becker (1948) has been applied to the digestive gland of the gastropod Helix pomatia. In the original technique the ferric 8-hydroxyquinoline formed by the enzymic hydrolysis of quinolyl-8-glucuronide, in a saturated solutionof ferric 8-hydroxyquinoline, was converted to Prussian blue. The Prussian blue conversion is omitted in the technique described in this paper as it appears to introduce errors in localization. The ferric 8-hydroxyquinoline crystals are sufficiently characteristic to be used as the end-point of the technique. The results obtained suggest that β-glucurcnidase is confined to the digestive cells in the digestive gland of the snail, and is associated with secretory granules in them.

Characterization of frozen hydrated biological specimens by low-loss EELS

1992 ◽  
Vol 50 (2) ◽  
pp. 1572-1573
Author(s):  
Songquan Sun ◽  
Richard D. Leapman
Keyword(s):  
Water Content ◽  
Direct Method ◽  
Internal Standard ◽  
Dry Weight ◽  
Dark Field ◽  
Protein Solutions ◽  
Subcellular Compartment ◽  
Differential Shrinkage ◽  
Electron Energy Loss

Analyses of ultrathin cryosections are generally performed after freeze-drying because the presence of water renders the specimens highly susceptible to radiation damage. The water content of a subcellular compartment is an important quantity that must be known, for example, to convert the dry weight concentrations of ions to the physiologically more relevant molar concentrations. Water content can be determined indirectly from dark-field mass measurements provided that there is no differential shrinkage between compartments and that there exists a suitable internal standard. The potential advantage of a more direct method for measuring water has led us to explore the use of electron energy loss spectroscopy (EELS) for characterizing biological specimens in their frozen hydrated state.We have obtained preliminary EELS measurements from pure amorphous ice and from cryosectioned frozen protein solutions. The specimens were cryotransfered into a VG-HB501 field-emission STEM equipped with a 666 Gatan parallel-detection spectrometer and analyzed at approximately −160 C.

STEM measurement of subcellular water distributions

1993 ◽  
Vol 51 ◽  
pp. 568-569
Author(s):  
R.D. Leapman ◽  
S.Q. Sun ◽  
S-L. Shi ◽  
R.A. Buchanan ◽  
S.B. Andrews
Keyword(s):  
Water Content ◽  
Internal Standard ◽  
Dry Weight ◽  
Dry Mass ◽  
Scanning Transmission Electron Microscope ◽  
Dark Field ◽  
Bulk Water ◽  
Inelastic Electron ◽  
Scanning Transmission ◽  
Annular Dark Field

Recent advances in rapid-freezing and cryosectioning techniques coupled with use of the quantitative signals available in the scanning transmission electron microscope (STEM) can provide us with new methods for determining the water distributions of subcellular compartments. The water content is an important physiological quantity that reflects how fluid and electrolytes are regulated in the cell; it is also required to convert dry weight concentrations of ions obtained from x-ray microanalysis into the more relevant molar ionic concentrations. Here we compare the information about water concentrations from both elastic (annular dark-field) and inelastic (electron energy loss) scattering measurements.In order to utilize the elastic signal it is first necessary to increase contrast by removing the water from the cryosection. After dehydration the tissue can be digitally imaged under low-dose conditions, in the same way that STEM mass mapping of macromolecules is performed. The resulting pixel intensities are then converted into dry mass fractions by using an internal standard, e.g., the mean intensity of the whole image may be taken as representative of the bulk water content of the tissue.

Reproduction of the Roman snail (Helix pomatia L.) from a local natural population in farm conditions and in a natural habitat

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Maciej Ligaszewski ◽  
Przemysław Pol
Keyword(s):  
Natural Population ◽  
Natural Habitat ◽  
Local Population ◽  
Helix Pomatia ◽  
Second Phase ◽  
Animal Reproduction ◽  
Snail Helix Pomatia ◽  
June July ◽  
A Site

AbstractThe aim of this study was to compare the quality of clutches and reproduction results of two groups of Roman snails (Helix pomatia) from the same local population, laying eggs simultaneously in semi-natural farm conditions and in a natural habitat. The study material were Roman snails aged 2 or more years which had entered the third phenological season of their life and thus the first season of sexual maturity. Observations were conducted at an earthen enclosure in a greenhouse belonging to the experimental farm for edible snails at the National Research Institute of Animal Reproduction in Balice near Kraków (Poland) as well as at a site where a local population naturally occurs in the uncultivated park surrounding the Radziwiłł Palace. In the June-July season, differences among such parameters as weight of clutch, number of eggs in clutch, mean egg weight, and hatchling percentage when compared to the total number of eggs in the clutch were compared. It was determined that clutches of eggs from the natural population laid in the greenhouse were of lesser weight (P<0.01), contained fewer eggs (P<0.05), and the mean weight of individual eggs was less (P<0.05) than in clutches laid simultaneously in a natural habitat. Both in the greenhouse and the natural habitat, in the first phase of laying eggs (June) the weight of the clutch and number of eggs its contained were greater than in the second phase (July). However, only for snails laying eggs in the greenhouse were these differences statistically significant (P<0.05) and highly significant (P<0.01), respectively. Statistically significant differences were not observed in hatchling percentage between eggs laid in the greenhouse and the natural habitat. The lower number of eggs laid in the farmed conditions of the greenhouse was successfully compensated for by the absence of mass destruction by rodents which occurred in the natural habitat.

scholarly journals Functional ecology of the biological soil crust in semiarid SE Spain: sun and shade populations of Diploschistes diacapsis (Ach.) Lumbsch.

2005 ◽  
Vol 37 (5) ◽  
pp. 425-432 ◽  
Author(s):  
Ana PINTADO ◽  
Leopoldo G. SANCHO ◽  
T. G. Allan GREEN ◽  
José Manuel BLANQUER ◽  
Roberto LÁZARO
Keyword(s):  
Water Content ◽  
Chlorophyll Content ◽  
Unit Area ◽  
Biological Soil Crust ◽  
Dry Weight ◽  
Mean Annual Precipitation ◽  
Plant Colonization ◽  
Soil Crust ◽  
Active Time ◽  
Exposed Population

The Tabernas badlands in semiarid south-east Spain is one of the driest regions in Europe with a mean annual precipitation of c. 240 mm. The landscape is deeply dissected, with canyons, ramblas and sparsely vegetated eroded badland slopes. The vegetation is predominantly a biological soil crust consisting of different types of lichen-rich communities, one of the more conspicuous being dominated by Diploschistes diacapsis (Ach.) Lumbsch. This lichen is mainly restricted to the north- facing slopes, where it forms extensive whitish carpets and probably plays an important role in preventing erosion of the slopes and allowing plant colonization. South-facing slopes are much more eroded and generally lack vegetation. %The photosynthetic performance of north (shade) and south-facing (sun) populations of D. diacapsis was studied to determine if these different populations showed any adaptations to the microclimatic conditions of their individual habitats. The response of CO2 exchange to light intensity, temperature and water content was measured under controlled conditions in the laboratory. Dry weight-based net photosynthetic rates were higher in the southern-exposed population but quantum efficiency, and light compensation points were similar. Thallus weight per unit area (LMA) was considerably higher for shade specimens but maximum water content and optimal water content were very similar and chlorophyll content on a dry weight basis was also similar. Chlorophyll content on an area basis was higher in the northern-exposed population and always much larger than those reported in other studies on the same species (up to 8 times larger) with the result that NP values on a chlorophyll basis were relatively low. The larger LMA meant that shade thalli stored more water per unit area which should ensure longer active periods than sun thalli. The results support a strategy pair of high NP and short active time versus low NP and long active time, both having been reported for other soil crust species. However, the visibly larger biomass of the shade D. diacapsis suggests that the lichen is at the limit of its adaptability in these habitats.

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