The Effect of Fertilisation on the Permeability to Water and on Certain Other Properties of the Surface of the Egg of Psammechinus Miliaris

1932 ◽  
Vol 9 (1) ◽  
pp. 69-92
Author(s):  
A. D. HOBSON
Keyword(s):  
Sea Water ◽  
Tap Water ◽  
Surrounding Medium ◽  
Volume Changes ◽  
Single Experiment ◽  
Stage Of Development ◽  
Maximum Value ◽  
Hypertonic Solutions ◽  
Psammechinus Miliaris

1. A photographic method is described for recording volume changes in seaurchin eggs. 2. The behaviour of the eggs of Psammechinus miliaris, both before and at various intervals after fertilisation, in relation to osmotic changes in the surrounding medium have been investigated. 3. The rate of entrance of water from hypotonic sea water into the egg increases immediately after fertilisation takes place, rises to a first maximum at about 3 min. after fertilisation. It then falls to a comparatively low value at about 5 min. after fertilisation. After this the rate increases steadily to a maximum value which is reached about 35 min. after fertilisation. It remains steady until just before cleavage when, in the single experiment continued until this stage of development, it decreased very markedly. 4. The action of hypertonic solutions on the egg has been examined. Several types of plasmolysis occur and are characteristic of different stages in the development of the egg after fertilisation. The type of plasmolysis is determined principally by the physical properties of the egg surface. The plasmolysis method is of little use in this material for the determination of relative permeability to dissolved substances at different stages of development. 5. The rate of cytolysis in tap water has been investigated and its relation to permeability of the egg surface to water is considered. There is a susceptible period followed by one of resistance during the first 5-10 min. after fertilisation. The rate of cytolysis is conditioned, not only by the rate of entrance of water but also by the degree to which the cell surface will withstand stretching. The latter may be a significant factor. 6. The rate of Zytolysis in extremely hypertonic solutions of sea water + NaCl has been examined. It increases to a maximum at about 5-10 min. after fertilisation. Thereafter it decreases. Cytolysis in the unfertilised egg and just after fertilisation is a sudden process. Later it becomes more and more gradual and progresses slowly from the surface to the interior of the egg. The relation between the rate of cytolysis and permeability is uncertain.

On the Vitelline Membrane of the Egg of Psammechinus Miliaris and of Teredo Norvegica

1932 ◽  
Vol 9 (1) ◽  
pp. 93-106
Author(s):  
A. D. HOBSON
Keyword(s):  
Sea Water ◽  
Tap Water ◽  
Elastic Solid ◽  
Vitelline Membrane ◽  
Hypertonic Solution ◽  
Perivitelline Space ◽  
Free Zone ◽  
Hypertonic Solutions ◽  
Psammechinus Miliaris ◽  
Entire Cell

I. Direct microscopic examination of the unfertilised eggs of Psammechinus miliaris and Teredo norvegica merely shows the existence of a thin, granule-free zone covering the surface. Whether this is continuous with the general cytoplasm or not cannot be made out with certainty by direct observation. 2. A cone of clear material can be drawn out from the surface of the unfertilised egg of both species by means of the microdissection needle. A definite membrane cannot be separated in this way. 3. Hypertonic solutions cause the egg of Psammechinus to shrink smoothly at first and later to become wrinkled. This is consistent with the view that the egg is surrounded by an elastic, solid layer which is normally in a state of tension. 4. Cytolysis of the egg of Psammechinus in tap water is not accompanied by bursting. The egg swells and is perfectly smooth and spherical when cytolysis is completed. This points to the existence of an elastic, solid surface layer. 5. Plasmolysis of the egg of Teredo is of the type here called "polyhedral."The irregular shape of the egg in the hypertonic solution is only temporary, as a clear membrane separates from the concave surfaces and the egg then becomes more or less spherical. 6. The protoplasm of the plasmolysed egg of Teredo behaves as a viscous fluid. 7. Cytolysis of the egg of Teredo in tap water is accompanied by bursting and dispersion of the entire cell contents. A crumpled membrane alone remains. 8. It is concluded that the unfertilised egg of both Teredo norvegica and Psammechinus miliaris is surrounded by an elastic vitelline membrane which is much a Vitelline Membrane of the Egg of P. miliaris and of T. norvegica 105 thicker in the former than in the latter. The vitelline membrane in both cases is tightly attached to the egg surface. 9 . In calcium-free sea water the fertilisation membrane is elevated normally in Psammechinus miliaris. It does not harden, however, and gradually sinks back on to the surface of the egg owing, apparently, to the loss by diffusion of the osmotically active substance in the perivitelline space. It can be elevated a second time by puncturing the surface of the egg and allowing some of the cell contents to penetrate into the perivitelline space. 10. It is suggested that one action of hypertonic solutions in inducing artificial parthenogenesis may be to cause a loosening of the attachment of the vitelline membrane to the egg surface.

scholarly journals Accurate determination of pesticides, hormones and endocrine disruptor compounds in complex environmental samples using matrix dilution and matrix matching with dispersive liquid–liquid microextraction

2018 ◽  
Vol 90 (11) ◽  
pp. 1703-1711 ◽  
Author(s):  
Dotse Selali Chormey ◽  
Merve Fırat ◽  
Çağdaş Büyükpınar ◽  
Fatih Erulaş ◽  
Okan Tarık Komesli ◽  
...  
Keyword(s):  
Environmental Samples ◽  
Sea Water ◽  
Tap Water ◽  
Accurate Determination ◽  
Deionized Water ◽  
Complex Nature ◽  
Calibration Standards ◽  
Dispersive Liquid Liquid Microextraction ◽  
Liquid Microextraction

AbstractQuantitative determination of contaminants in environmental samples is usually hampered by low analyte recovery which results from the complex nature of the sample matrix. This study presents the application of a developed dispersive liquid–liquid microextraction method for the determination of 12 analytes in environmental samples including sea water, fresh water (lake, well and tap water), brackish water and soil samples. Matrix matched standards were used to compensate for the low analyte recovery recorded by the conventional calibration method. The effect of matrix dilution on analyte recovery was also tested. All matrix matched and matrix diluted spiked recoveries were done concurrently with calibration standards prepared in deionized water. Percent recoveries recorded for the analytes according to deionized water calibration standards ranged between 66 and 137%. Matrix matching and matrix dilution yielded close to 100% recovery results, but the later lowered the detection limit according to the dilution factor.

Researches on Thermo-Electric Properties of Seawater and Al2O3 Nanofluids

2013 ◽  
Vol 394 ◽  
pp. 14-19 ◽  
Author(s):  
Jung Chang Wang ◽  
Wen Chou Chiang
Keyword(s):  
Future Development ◽  
Mineral Water ◽  
Sea Water ◽  
Operating Temperature ◽  
Tap Water ◽  
Output Current ◽  
Thermo Electric ◽  
Maximum Value ◽  
Complementary Role ◽  
The Impact

The article utilizes thermo-electric performance experiments to study four fixed volume kinds of electrolytes (Tap Water, Mineral Water, Sea Water, and Al2O3 Nanofluids) under different operating temperatures, distances and areas of electrodes due to the impact of the output currents. The experimental results showed that the rise in operating temperature will significantly affect the magnitude of the output current because of heat convection inside the fluid. And the output current of the seawater was much larger than those of the nanofluids, tap water and mineral water between 27 °C and 90 °C. Its maximum value was up to 4.2 mA. However, the seawater presented unstable for output current. The Al2O3 nanofluids had the most stable among them and its output current was about 1.08 mA. If seawater combined with Al2O3 nanoparticles, they will be able to achieve a complementary role in the future development.

scholarly journals Determination of the fenvalerate insecticide in natural waters by a photochemically-induced fluorescence method

2015 ◽  
Vol 34 (2) ◽  
pp. 245 ◽  
Author(s):  
Diène Diégane Thiaré ◽  
Atanasse Coly ◽  
Diégane Sarr ◽  
Abdourakhmane Khonté ◽  
Amadou Diop ◽  
...  
Keyword(s):  
Natural Waters ◽  
Sea Water ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Irradiation Time ◽  
Tap Water ◽  
Analytical Sensitivity ◽  
Photochemically Induced Fluorescence ◽  
Relative Standard

<p>The fenvalerate pyrethroid insecticide was determined in various types of natural waters of Senegal by means of a newly-developed, simple, rapid and very sensitive photochemically-induced fluorescence (PIF) method. The PIF method was optimized with respect to the irradiation time, solvent and pH. The obtained calibration curves yielded correlation coefficients very close to unity. The limit of detection (LOD) and of quantification (LOQ) values were very low (LOD = 0.01–0.66 ng/ml and LOQ = 0.04–2.20 ng/ml, according to the solvent), and the relative standard deviation (RSD) values were small, ranging between 0.1 and 1.5 %, which indicated a very good analytical sensitivity and a great repeatability of PIF. Recovery studies were performed on spiked distilled water, tap water, sea water, well water, river water and draining water samples of Senegal, using the liquid-liquid extraction (LLE), solid phase extraction (SPE), and standard addition procedures. Satisfactory recovery results (about 85–121%) were obtained for the determination of fenvalerate in an aquatic environment.</p>

Determination of Trace Amounts of Lead Using the Flotation-spectrophotometric method

2011 ◽  
Vol 6 ◽  
pp. ACI.S5948b
Author(s):  
Sabah Shiri ◽  
Ali Delpisheh ◽  
Ali Haeri ◽  
Abdolhossein Poornajaf ◽  
Babak Golzadeh ◽  
...  
Keyword(s):  
Water Samples ◽  
Sea Water ◽  
Tap Water ◽  
Molar Absorptivity ◽  
Alizarin Yellow ◽  
Low Concentrations ◽  
Relative Standard ◽  
Seawater Samples ◽  
Almost All

The present study describes a simple and highly selective method for separation, preconcentration and spectrophotometric determination of extremely low concentrations of lead. It is based on flotation of a complex of Pb2+ ions and Alizarin yellow between aqueous and n-hexane interface at pH = 6. The proposed procedure is also applied for determination of lead in both tap water and prepared sea water samples. Beer's Law was obeyed over the concentration range of 3.86 × 10-8 To 8.20 × 10-7 molL-1 (8-170 ngmL-1) with an apparent molar absorptivity of 1.33 × 106 molL-1 cm-1 for a 100 mL aliquot of the water sample. The detection limit (n = 10) was 8.7 × 10-9 molL-1 (1.0 ngmL-1) and the Relative standard deviation (R.S.D), (n = 10) for 7.2 × 10-7 molL-1 (150 ngmL-1) of Pb (II) was 4.36%. A notable advantage of the method is that the determination of Pb (II) is free from the interference of almost all cations and ions found in the environment and waste water samples. The determination of Pb (II) in tap and synthetic seawater samples was also carried out by the present method. The results were satisfactorily comparable so that the applicability of the proposed method was confirmed to the real samples.

scholarly journals Determination of Trace Amounts of Lead Using the Flotation-spectrophotometric method

2010 ◽  
Vol 5 ◽  
pp. ACI.S5948 ◽  
Author(s):  
Sabah Shiri ◽  
Ali Delpisheh ◽  
Ali Haeri ◽  
Abdolhossein Poornajaf ◽  
Babak Golzadeh ◽  
...  
Keyword(s):  
Water Samples ◽  
Sea Water ◽  
Tap Water ◽  
Molar Absorptivity ◽  
Alizarin Yellow ◽  
Low Concentrations ◽  
Relative Standard ◽  
Seawater Samples ◽  
Almost All

The present study describes a simple and highly selective method for separation, preconcentration and spectrophotometric determination of extremely low concentrations of lead. It is based on flotation of a complex of Pb2+ ions and Alizarin yellow between aqueous and n-hexane interface at pH = 6. The proposed procedure is also applied for determination of lead in both tap water and prepared sea water samples. Beer's Law was obeyed over the concentration range of 3.86 × 10−8 To 8.20 × 10−7 molL−1 (8-170 ngmL−1) with an apparent molar absorptivity of 1.33 × 106 molL−1 cm−1 for a 100 mL aliquot of the water sample. The detection limit (n = 10) was 8.7 × 10−9 molL−1 (1.0 ngmL−1) and the Relative standard deviation (R.S.D), (n = 10) for 7.2 × 10−7 molL−1 (150 ngmL−1) of Pb (II) was 4.36%. A notable advantage of the method is that the determination of Pb (II) is free from the interference of almost all cations and ions found in the environment and waste water samples. The determination of Pb (II) in tap and synthetic seawater samples was also carried out by the present method. The results were satisfactorily comparable so that the applicability of the proposed method was confirmed to the real samples.

scholarly journals Simultaneous Determination of Iron and Cobalt using Spectrophotometry after Catanionic Mixed Micellar Cloud Point Extraction Procedure

2020 ◽  
Vol 36 (6) ◽  
pp. 1168-1172
Author(s):  
Ravi Kumar Kakitha ◽  
Shyamala Pulipaka ◽  
Deva Hari Puranam
Keyword(s):  
Mixed Micelles ◽  
Sea Water ◽  
Tap Water ◽  
Sodium Dodecyl ◽  
Extraction Procedure ◽  
Maximum Efficiency ◽  
Hcl Concentration ◽  
Cationic And Anionic Surfactants ◽  
Preconcentration Method

A new preconcentration method which utilises a mixture of cationic and anionic surfactants for separation and spectrophotometric determination of iron and cobalt simultaneously has been developed. The metal ions, iron and cobalt were complexed with thiocyante. The hydrophobic complexes of iron and cobalt were then extracted into catanionic mixed micelles of cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulphate (SDS). Different parameters like concentration of HCl, concentration of thiocyanate, concentrations of the surfactants (CTAB and SDS), equilibration temperature and time were studied to get maximum efficiency. The linear ranges of Fe3+ and Co2+ were found to be 0.139 – 0.838 μg mL–1 and 5.89 – 35.4 μg mL–1, respectively the detection limits obtained were 1.54 ng mL–1 and 6.18 ng mL–1. The developed procedure has been employed for the retrieval of Fe3+ and Co2+ in water samples successfully (tap water and sea water). 98 – 107% recoveries were obtained.

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