scholarly journals The Effect of Salts on the Anal Gills of the Mosquito Larva

1933 ◽  
Vol 10 (1) ◽  
pp. 1-14 ◽  
Author(s):  
V. B. WIGGLESWORTH
Keyword(s):  
Mosquito Larva ◽  
Divalent Cations ◽  
Complete Separation ◽  
Elastic Membrane ◽  
Hypertonic Solutions ◽  
Elastic Filaments ◽  
Granular Cytoplasm ◽  
Visible Effect ◽  
The Difference ◽  
Elastic Fibrils

The so-called anal gills of the mosquito larvae (Aedes argenteus) are delicate chitinous papillae lined by flattened cells and filled with haemolymph. Externally the cells rest directly upon the chitinous cuticle. Internally they are bounded by a continuous elastic membrane, apparently composed of some "scleroprotein." The faintly granular cytoplasm is crossed vertically by elastic fibrils or membranes. If the gills are cut off in various salt solutions, which can then come in contact with the cells on both their surfaces, the cells swell or contract like other tissues, depending on whether the solutions are hypo- or hypertonic. But if the same solutions are applied to the intact larva, so that they come in contact with the outer surface while the inner surface of the cells is still in contact with the haemolymph, the effects are altogether different: Hypotonic solutions have no visible effect. Hypertonic solutions of salts like NaCl, KBr, etc., in which both ions are monovalent, cause enormous swelling of the cells. This is probably because these salts diffuse through the outer membrane (the cuticle) of the gills into the cells, which then absorb water from the haemolymph by osmosis. If the larva so treated is soon restored to fresh water, the action is reversible; but after a time the elastic filaments in the cells are dissolved and these can no longer contract again. These effects occur equally in the presence of salts with divalent cations. Hypertonic solutions of salts like CaCl2, Na2SO4, etc., in which one or both ions are divalent, extract water from the larva but do not cause swelling of the cells. These salts do not dissolve the elastic filaments. In the presence of hypotonic NaCl, etc. (which by itself has no visible effect), they cause temporary swelling followed by contraction. The cause of the difference between these two groups of salts is discussed. Dilute alkalis (N/50 NaOH) applied to the isolated gill or the intact larva dissolve the cells and cause extreme swelling, but do not dissolve the cuticle or the inner membrane. This action is accentuated by NaCl, etc., and by Na2SO4, etc., but is partially inhibited by CaCl2. Dilute acids (N/100 HCl) cause precipitation of the nuclei, slight swelling of the cells, and complete separation from the cuticle. In the presence of hypertonic Na2SO4 or CaCl2 the separation does not occur. All these effects are peculiar to the gills; no other part of the surface of the larvae is affected by these reagents.1

Accuracy and precision in stock separation of north-east Arctic and Norwegian coastal cod by otoliths - comparing readings, image analyses and a genetic method

2005 ◽  
Vol 56 (5) ◽  
pp. 753 ◽  
Author(s):  
Erik Berg ◽  
Tuula H. Sarvas ◽  
Alf Harbitz ◽  
Svein Erik Fevolden ◽  
Arnt Børre Salberg
Keyword(s):  
Visual Inspection ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Complete Separation ◽  
Arctic Cod ◽  
Genetic Method ◽  
North East ◽  
Accuracy And Precision ◽  
Growth Zones ◽  
The Difference

The distinction between north-east Arctic cod and Norwegian coastal cod, two major groups of Atlantic cod (Gadus morhua L.), has for many years been based on different distance and shape similarities between the two first translucent growth zones in the otoliths, subjectively decided by visual inspection in a binocular. To analyse the certainty of this technique, four independent readers have classified 263 cod otoliths in total from five different geographical areas. For three of the readers, between 82% and 89% of the classification results coincided with independent results based on genetic analyses. Further, 38 cod otoliths, where the readers were certain of the classification (21 north-east Arctic cod and 17 coastal cod) were classified by several image analysis methods. A complete separation was obtained by using the ratio of the circumferences of the two zones, providing a typical ratio of approximately 2 for coastal and 1.5 for north-east Arctic cod. The otolith method for separating the two types of cod has been considered adequately accurate in assessing the two stocks of cod. However, the method is sensitive to subjective interpretation, and action needs to be taken to minimise the difference in interpretation among otolith readers.

scholarly journals Shear stress activation of platelet glycoprotein IIb/IIIa plus von Willebrand factor causes aggregation: filter blockage and the long bleeding time in von Willebrand's disease

Blood ◽  
1987 ◽  
Vol 70 (5) ◽  
pp. 1354-1361 ◽  
Author(s):  
JR O'Brien ◽  
GP Salmon
Keyword(s):  
Shear Stress ◽  
Bleeding Time ◽  
Platelet Rich Plasma ◽  
Divalent Cations ◽  
Mean Transit Time ◽  
Platelet Glycoprotein ◽  
High Shear ◽  
The Difference ◽  
Von Willebrand’S Factor ◽  
Induced Aggregation

The article explores the finding that high shear alone applied to normal, native blood results in platelet aggregation. A filter with tortuous capillary-sized channels permits a study of the effect of shearing forces at different pressures. Native, heparinized, citrated and EDTA blood and platelet-rich plasma (PRP) were forced through the filter. Normal and von Willebrand's blood were studied, as were the effects of antibodies to platelet glycoproteins (GPr) and to von Willebrand's factor (vWf) and of “membrane-active” drugs. Normally, the filter blocked at 40 mmHg but not at 5 mmHg. Transmission electronmicroscopy of the filter at 40 mmHg showed blockage by platelet aggregates. Initially, the mean transit time through the filter was 8 milliseconds. Platelet retention in the filter occurred in two phases. From 0 to 3 seconds, only high-shear, vWf, and GPrIIb/IIIa were required. From 10 to 20 seconds, retention presumably involved these three attributes, but divalent cations were also essential. Only this phase was inhibited by some membrane-active drugs. ADP- and thrombin- induced aggregation requires GPrIIb/IIIaand fibrinogen. Shear-induced blocking of the filter by blood with a normal concentration of fibrinogen requires GPrIIb/IIIa and vWf. This indicates a different type of exposure of GPrIIb/IIIa. The long bleeding time in vW disease highlights the absolute requirement for vWf and emphasizes the difference in exposure of GPrIIb/IIIa induced by shear stress. Evidently, a process similar to that occurring in the filter is required in normal capillary hemostasis.

261 LABELING SEX-SPECIFIC DNA SEQUENCES IN MAMMALIAN SPERM

2008 ◽  
Vol 20 (1) ◽  
pp. 210
Author(s):  
B. A. Didion ◽  
R. Bleher
Keyword(s):  
Dna Sequences ◽  
Somatic Cells ◽  
Complete Separation ◽  
Cell Nuclei ◽  
Metaphase Chromosomes ◽  
Telomeric Sequences ◽  
Synthetic Dna ◽  
Y Chromosomes ◽  
Boar Sperm ◽  
The Difference

While flow cytometric separation of X- andY-chromosome- bearing sperm has advanced to the point of acceptance in the commercial production of sex-preselected cattle, it is important to continue researching this area to improve efficiencies. For example, the difference in DNA sequence between the X- andY-chromosomes has merit as a foundation for an alternative sperm sexing approach that could enable the complete separation and use of an entire ejaculate. We used synthetic DNA mimics conjugated to a fluorescent dye for in situ detection of Y-chromosomes in metaphase preparations of porcine somatic cells and spermatozoa. Peptide nucleic acids (PNA) are synthetic compounds with higher affinity and stability than conventional DNA probes and are used as specific hybridization probes to complementary DNA. The application of PNA probes was demonstrated previously in telomere analysis studies, and we confirmed their efficacy using a CY3-(CCCTAA)3 PNA to probe bull and boar sperm telomeric sequences. Using male porcine somatic cells and theY-chromosome as a template, we arranged for the synthesis of a CY3-conjugated PNA to bind 13-15 base pairs of unique, Y-chromosome sequence. By testing different labeling conditions, we found that brief incubation of metaphase chromosomes with the PNA produced a localized signal on theY-chromosome. No signals were present when chromosomes of porcine female somatic cells were incubated with the PNA probes. Because chromosomes occupy non-random territories in all cell nuclei including those in sperm, we expected to find centrally located signals in 50% of fixed boar sperm when these were treated with the same PNA as used for the somatic cells. We found the signals present in 161 of 302 (53.3%) sperm to consist of a single, centrally located, round fluorescent dot in the sperm head. Further research is required to establish the uptake of PNA in live sperm toward evaluation of this approach for sperm sexing.

ECONOMY OF TIME IN LABORATORY DISTILLATION

1931 ◽  
Vol 5 (4) ◽  
pp. 455-465
Author(s):  
D. F. Stedman
Keyword(s):  
Methyl Alcohol ◽  
Critical Value ◽  
Complete Separation ◽  
Volatile Constituent ◽  
Reflux Ratio ◽  
Correction Factors ◽  
Boiling Points ◽  
Efficient Column ◽  
The Difference ◽  
Theoretical Amount

The mathematics of fractional distillation of ideal mixtures has been condensed, so that the most economical "reflux ratio" for any such mixture may be decided at once.Particular use is made of the "critical reflux ratio" for any mixture, above which even an infinite column cannot obtain complete separation; and the relation of this critical value to the most economical value for any particular case is given.Some of the conclusions with respect to the infinite column were tested by means of a mixture of methyl and ethyl alcohols using a particularly efficient column. It was found that the vapor produced in the still contained slightly more than the theoretical amount of methyl alcohol, and the magnitude of such error is illustrated from previous work on glycerine solutions.The results are given in the form of a graph of the "critical reflux ratio" for the case where the most volatile constituent boils at 100 °C., and the difference between the boiling points varies from 0.25 °C. to 32 °C., the concentration of the most volatile constituent also being included from 0.001 to 1.0.A table of correction factors is also given, showing the factor by which the "critical reflux ratio" should be varied to produce the greatest economy of time for any particular case.

scholarly journals The Function of the Anal Gills of the Mosquito Larva

1933 ◽  
Vol 10 (1) ◽  
pp. 16-26 ◽  
Author(s):  
V. B. WIGGLESWORTH
Keyword(s):  
Carbon Dioxide ◽  
Body Surface ◽  
Mosquito Larva ◽  
Anterior Part ◽  
Pure Water ◽  
Posterior Part ◽  
The Body ◽  
Glycerol Water ◽  
Hypertonic Solutions ◽  
Spontaneous Aggregation

The anal gills of the mosquito larva (Aedes argenteus) are the only region of the body that is freely permeable to water. In hypertonic solutions of sugar or glycerol, water is extracted from the gills and the larva shrinks. In pure water this is absorbed by the gills and later excreted by the Malpighian tubes. The absorption of water appears to be effected mainly by osmosis. Larvae can mature without the gills, but they seem to grow more slowly, and show almost no parenteral absorption of water. Normally the larva swallows very little fluid. The fluid in the gut is probably secreted in the posterior part of the mid-gut and reabsorbed in the anterior part and in the caeca. Some of the water excreted by the Malpighian tubes is reabsorbed in the rectum. As judged by the spontaneous aggregation of the flagellate Polytoma, oxygen is absorbed by submerged larvae all over the body surface, but most actively at the base of the gills. Carbon dioxide is given off equally all over the body surface. It is concluded that the anal gills are primarily water-absorbing organs, and are only incidentally concerned in respiration.

scholarly journals Urine Metabolome during Parturition

Metabolites ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 290
Author(s):  
Federica Gevi ◽  
Alessandra Meloni ◽  
Rossella Mereu ◽  
Veronica Lelli ◽  
Antonella Chiodo ◽  
...  
Keyword(s):  
Urinary Metabolites ◽  
Ultra Performance Liquid Chromatography ◽  
Complete Separation ◽  
Urine Samples ◽  
Hydrophilic Interaction ◽  
Multivariate Statistical ◽  
Highly Sensitive ◽  
Powerful Approach ◽  
The Difference ◽  
Invasive Techniques

In recent years, some studies have described metabolic changes during human childbirth labor. Metabolomics today is recognized as a powerful approach in a prenatal research context, since it can provide detailed information during pregnancy and it may enable the identification of biomarkers with potential diagnostic or predictive. This is an observational, longitudinal, prospective cohort study of a total of 51 serial urine samples from 15 healthy pregnant women, aged 29–40 years, which were collected before the onset of labor (out of labor, OL). In the same women, during labor (in labor or dilating phase, IL-DP). Samples were analyzed by hydrophilic interaction ultra-performance liquid chromatography coupled with mass spectrometry (HILIC-UPLC-MS), a highly sensitive, accurate, and unbiased approach. Metabolites were then subjected to multivariate statistical analysis and grouped by metabolic pathway. This method was used to identify the potential biomarkers. The top 20 most discriminative metabolites contributing to the complete separation of OL and IL-DP were identified. Urinary metabolites displaying the largest differences between OL and IL-DP belonged to steroid hormone, particularly conjugated estrogens and amino acids much of this difference is determined by the fetal contribution. In addition, our results highlighted the efficacy of using urine samples instead of more invasive techniques to evaluate the difference in metabolic analysis between OL and IL-DP.

Fine-Needle Aspirates of Adenocarcinoma/Metastatic Carcinoma That Resemble Hepatocellular Carcinoma: Correlating Cytologic Features and Performance in the College of American Pathologists Nongynecologic Cytology Program

2005 ◽  
Vol 129 (10) ◽  
pp. 1217-1221
Author(s):  
Andrew A. Renshaw ◽  
Jennifer Haja ◽  
David C. Wilbur ◽  
Theodore R. Miller
Keyword(s):  
Hepatocellular Carcinoma ◽  
Fine Needle Aspiration ◽  
Needle Aspiration ◽  
Metastatic Carcinoma ◽  
Time Range ◽  
Fine Needle ◽  
Fine Needle Aspirates ◽  
Granular Cytoplasm ◽  
The Difference ◽  
And Performance

Abstract Context.—The cytologic features of adenocarcinoma/ metastatic carcinoma in liver fine-needle aspirates are well described. We review the cytologic findings from 16 aspirates of adenocarcinoma/metastatic carcinoma that were frequently misclassified as hepatocellular carcinomas and compare them with 17 cases that were rarely misclassified. Objective.—To compare the cytologic features of adenocarcinoma/metastatic carcinoma in fine-needle aspiration specimens of the liver that were frequently misclassified as hepatocellular carcinoma with those of aspirates that were rarely misclassified. Design.—We reviewed a total of 1712 interpretations from 33 different cases of adenocarcinoma/metastatic carcinoma tumor in liver fine-needle aspiration specimens in the College of American Pathologists Nongynecologic Cytology Program and correlated the cytologic features with performance in the program. Results.—Overall, cases that were frequently misclassified as hepatocellular carcinoma were misclassified on average 26% of the time (range, 13%–54%), while infrequently misclassified cases were interpreted as hepatocellular carcinoma on average 0.7% of the time (range, 0%– 3%). The difference was statistically significant (P < .001). On review, cases that were frequently misclassified most often had moderate amounts of granular cytoplasm (16/16 cases) and round nuclei with even chromatin (13/16 cases). Trabeculae (3/16 cases), bare nuclei (2/16 cases), and endothelial wrapping (1/16 cases) were also occasionally present. In contrast, cases that were rarely misclassified were more likely to have areas with cells showing scant cytoplasm that were crowded and overlapped or molded (13/17 cases) and contained dark hyperchromatic chromatin (13/17 cases) compared to cases that were frequently misclassified (P < .001 and P = .002, respectively). Trabeculae (2/17) and bare nuclei (2/17 cases) were also rarely present. Conclusion.—Cases of adenocarcinoma/metastatic carcinoma with moderate amounts of granular cytoplasm and round nuclei with even chromatin are frequently misclassified as hepatocellular carcinoma. Recognition of this problem, attention to cytologic criteria, and frequent use of immunohistochemical studies and core biopsy may help avoid this pitfall.

The role of divalent cations in the activation of the NADP+-specific isocitrate dehydrogenase from Pisum sativum L.

1977 ◽  
Vol 55 (9) ◽  
pp. 928-934 ◽  
Author(s):  
Robert J. Maloney ◽  
David T. Dennis
Keyword(s):  
Ionic Strength ◽  
Stability Constants ◽  
Isocitrate Dehydrogenase ◽  
Divalent Cations ◽  
Free Form ◽  
Saturation Kinetics ◽  
The Difference ◽  
The Stability ◽  
Kinetics Of

A divalent cation electrode was used to measure the stability constants (association constants) for the magnesium and manganese complexes of the substrates for the NADP+-specific isocitrate dehydrogenase (EC 1.1.1.42) from pea stems. At an ionic strength of 26.5 mM and at pH 7.4 the stability constants for the Mg2+–isocitrate and Mg2+–NADP+ complexes were 0.85 ± 0.2 and 0.43 ± 0.04 mM−1 respectively and for the Mn2+–isocitrate and Mn2+–NADP+ complexes they were 1.25 ± 0.07 and 0.75 ± 0.09 mM−1 respectively. At the same ionic strength but at pH 6.0 the Mg2+–NADPH and Mn2+–NADPH complexes had stability constants of 0.95 ± 0.23 and 1.79 ± 0.34 mM−1 respectively. Oxalosuccinate and α-ketoglutarate do not form measureable complexes under these conditions. Saturation kinetics of the enzyme with respect to isocitrate and metal ions are consistent with the metal–isocitrate complex being the substrate for the enzyme. NADP+ binds to the enzyme in the free form. Saturation kinetics of NADPH and Mn2+ indicate that the metal–NADPH complex is the substrate in the reverse reaction. In contrast the pig heart enzyme appears to bind free NADPH and Mn2+. A scheme for the reaction mechanism is presented and the difference between the reversibility of the NAD+ and NADP+ enzyme is discussed in relation to the stability of the NADH and NADPH metal complexes.

scholarly journals Regulation of Connexin Hemichannels by Monovalent Cations

2005 ◽  
Vol 127 (1) ◽  
pp. 67-75 ◽  
Author(s):  
Miduturu Srinivas ◽  
D. Paola Calderon ◽  
Jack Kronengold ◽  
Vytas K. Verselis
Keyword(s):  
Cell Death ◽  
Plasma Membrane ◽  
Divalent Cations ◽  
Signaling Molecules ◽  
Primary Effect ◽  
Monovalent Cations ◽  
Modest Increase ◽  
Monovalent Ions ◽  
The Difference ◽  
Connexin Hemichannels

Opening of connexin hemichannels in the plasma membrane is highly regulated. Generally, depolarization and reduced extracellular Ca2+ promote hemichannel opening. Here we show that hemichannels formed of Cx50, a principal lens connexin, exhibit a novel form of regulation characterized by extraordinary sensitivity to extracellular monovalent cations. Replacement of extracellular Na+ with K+, while maintaining extracellular Ca2+ constant, resulted in >10-fold potentiation of Cx50 hemichannel currents, which reversed upon returning to Na+. External Cs+, Rb+, NH4+, but not Li+, choline, or TEA, exhibited a similar effect. The magnitude of potentiation of Cx50 hemichannel currents depended on the concentration of extracellular Ca2+, progressively decreasing as external Ca2+ was reduced. The primary effect of K+ appears to be a reduction in the ability of Ca2+, as well as other divalent cations, to close Cx50 hemichannels. Cx46 hemichannels exhibited a modest increase upon substituting Na+ with K+. Analyses of reciprocal chimeric hemichannels that swap NH2- and COOH-terminal halves of Cx46 and Cx50 demonstrate that the difference in regulation by monovalent ions in these connexins resides in the NH2-terminal half. Connexin hemichannels have been implicated in physiological roles, e.g., release of ATP and NAD+ and in pathological roles, e.g., cell death through loss or entry of ions and signaling molecules. Our results demonstrate a new, robust means of regulating hemichannels through a combination of extracellular monovalent and divalent cations, principally Na+, K+, and Ca2+.

scholarly journals THE BEHAVIOR OF ELASTIC TISSUE IN THE POSTFETAL OCCLUSION AND OBLITERATION OF THE DUCTUS ARTERIOSUS (BOTALLI) IN SUS SCROFA

1914 ◽  
Vol 19 (2) ◽  
pp. 129-142 ◽  
Author(s):  
J. Parsons Schaeffer
Keyword(s):  
Connective Tissue ◽  
Sus Scrofa ◽  
Ductus Arteriosus ◽  
Elastic Fibers ◽  
Elastic Membrane ◽  
Tissue Cell ◽  
Elastic Tissue ◽  
Tissue Cells ◽  
Ductus Arteriosus Botalli ◽  
Elastic Fibrils

A study of the histogenesis of elastic tissue in the embryonic ductus arteriosus of Sus scrofa is in accord with the theory that elastic fibrils are directly differentiated in the outlying portion of the protoplasm of the early connective tissue cell. In the occlusion of the postfetal ductus arteriosus of Sus scrofa there is early a hypertrophy of the internal elastic membrane. Subsequently there takes place a marked delamination of the thickened internal elastic membrane in the production of new and independent elastic fibers and lamellæ. The formation of new elastic fibers from preformed elastic tissue is most abundant where the postfetal contraction of the ductus arteriosus is least marked. These new elastic fibers play an important part in the occlusion of the lumen of the postfetal ductus. Aside from the extensive formation of elastic fibers from preformed elastic tissue, in the occlusion of the lumen of the postfetal ductus arteriosus of Sus scrofa, there are also some elastic fibrils formed from non-elastic elements, apparently from connective tissue cells. In some recent preliminary work on ligations of the common carotid artery there was found, after an interval of from eight to twelve days, at some points between the ligatures, a slight but obvious cellular thickening of the so-called subendothelial stratum. Some of these connective tissue cells may have wandered from the other coats of the vessel, through the inner elastic membrane into the subendothelial stratum; others may have proliferated from cells in situ. Specific stains revealed near the periphery of some of these cells, i. e., in the outlying portion of the exoplasm, very delicate elastic fibrils, apparently the product of protoplasmic activity.

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