Properties of Na, K-ATPase from the salivary glands of the ixodid tick Amblyomma hebraeum

1980 ◽  
Vol 58 (6) ◽  
pp. 1052-1059 ◽  
Author(s):  
B. Rutti ◽  
B. Schlunegger ◽  
W. Kaufman ◽  
A. Aeschlimann
Keyword(s):  
Enzyme Activity ◽  
Salivary Glands ◽  
Fluid Secretion ◽  
Ixodid Tick ◽  
Rich Source ◽  
Amblyomma Hebraeum ◽  
Fundamental Properties ◽  
High Concentrations

Tick (Amblyomma hebraeum) salivary glands are a rich source of Na,K-ATPase (EC 3.6.1.3), the fundamental properties of which are similar to those of Na,K-ATPases from other sources. Inhibition of the enzyme by ouabain is quantitatively similar to the inhibition of fluid secretion by this drug. Harmaline at high concentrations also inhibited the Na,K-ATPase. The nucleotides GTP, ITP, and UTP were utilized as substrates, but all were less effective than ATP. Noradrenaline, dopamine, and phenoxybenzamine, all at concentrations known to influence fluid secretion in vitro, had no effect on enzyme activity.

The influence of various factors on fluid secretion by in vitro salivary glands of ixodid Ticks

1976 ◽  
Vol 64 (3) ◽  
pp. 727-742
Author(s):  
W. Kaufman
Keyword(s):  
Salivary Gland ◽  
Salivary Glands ◽  
Culture Medium ◽  
Dry Weight ◽  
Fluid Secretion ◽  
Ixodid Tick ◽  
Ixodid Ticks ◽  
Mammalian Tissue ◽  
Stimulating Factor

1. Salivary glands of the female ixodid tick, Dermacentor andersoni, secrete fluid in vitro when bathed in a slightly modified version of the mammalian tissue culture medium ‘TC 199′. 2. Rate of salivation in vitro increases with progression of feeding, but there is no comparable increase in dry weight of the salivary glands during the early phase of engorgement. Engorged ticks secreted at only 25% the rate of 90–250 mg ticks, indicating that salivary gland degeneration has already begun in the very early post-engorgement stage. 3. A salivary gland stimulating factor can be detected in the nervous system but not in other tissues. 4. Male salivary glands secrete at only 1/20th the rate of female glands. Thus males probably do not use their salivary glands as osmoregulatory organs. 5. From the uniform lack of response to ACh and uniform response to DA in 7 ixodid tick species, it is suggested that the control of salivation is similar throughout the ixodid family.

scholarly journals THE EFFECT OF CHANGES IN THE RESPIRATORY METABOLISM UPON GENOME ACTIVITY

1972 ◽  
Vol 55 (2) ◽  
pp. 257-265 ◽  
Author(s):  
Hans J. Leenders ◽  
Pieter J. A. Beckers
Keyword(s):  
Enzyme Activity ◽  
Salivary Glands ◽  
Actinomycin D ◽  
Maximum Size ◽  
Respiratory Metabolism ◽  
Maximum Increase ◽  
Drosophila Hydei ◽  
Nicotinamide Adenine Dinucleotide Dehydrogenase ◽  
Genome Activity

The in vitro regression of experimentally induced chromosome puffs was investigated in explanted salivary gland chromosomes of Drosophila hydei. It was observed that the regression of the puffs 2-32A, 2-36A, 2-48C, and 4-81B is accelerated if substrates for the respiratory metabolism are supplied to the cells. A similar effect can be produced by addition of KCN or oligomycin to medium in which intact salivary glands are incubated. The acceleration of puff regression by these substances occurs not only if the puff-inducing stimulus is removed but as well under conditions in which the stimulus is maintained. Regression of the puffs 2-32A, 2-36A, and 4-81B is inhibited if cycloheximide is present in the incubation medium. Chloramphenicol has no effect on puff regression. Measurements on nicotinamide adenine dinucleotide-dehydrogenase activity in homogenates of salivary glands revealed an increase in enzyme activity of 41 %. Maximum increase is attained at 30 min after the induced puffs have reached their maximum size. The increase in enzyme activity does not occur if the glands are kept in a medium containing either actinomycin D or cycloheximide. Chloramphenicol does not inhibit the increase in enzyme activity. The possible relationship between puff activity and its control as a result of changes in the respiratory metabolism is discussed.

scholarly journals Neural Involvement in the Control of Salivary Gland Degeneration in the Ixodid Tick Amblyomma Hebraeum

1984 ◽  
Vol 109 (1) ◽  
pp. 281-290
Author(s):  
ROBERT A. HARRIS ◽  
WILLIAM R. KAUFMAN
Keyword(s):  
Salivary Gland ◽  
Salivary Glands ◽  
Crude Extract ◽  
Seminal Receptacle ◽  
Ixodid Tick ◽  
Ixodid Ticks ◽  
Secretory Function ◽  
Amblyomma Hebraeum ◽  
Gland Function ◽  
Male Genital

1. We have developed a simple, quantitative assay to monitor salivary gland function in ixodid ticks. 2. Salivary glands of engorged (1.0-3.0g), or partially engorged (0.40-1.0g), Amblyomma hebraeum Koch lose virtually all secretory function within 4 days after engorgement. 3. Salivary glands from partially-fed ticks (0.20-0.30 g) lose 75 % of their secretory ability by 4 days post-removal, but retain this level of function for at least another 11 days. 4. Partially-fed ticks (0.20-0.30 g) removed from the host for 4 days and then allowed to re-attach and resume feeding for a further 2 days, recover much of their lost function. 5. Cutting the opisthosomal nerves of partially-fed ticks (0.40-1.0 g) inhibits salivary gland degeneration. 6. Excising the seminal receptacle from partially-fed ticks (0.40-1.0 g) inhibits salivary gland degeneration. Replacement of the seminal receptacle permits salivary gland degeneration to proceed normally. The factor from the seminal receptacle appears to be distinct from tick salivary gland degeneration factor (TSGDF; Harris & Kaufman, 1981). 7. Injecting a crude extract of male genital tracts into large, partially-fed ticks (0.40-1.0 g), which had had their seminal receptacles removed, caused virtually complete salivary gland degeneration. Such ticks, when injected with an extract of male salivary glands, showed no such degeneration. This suggests that the factor associated with mating originates in the male and is transferred to the female during copulation.

Ion and Water Balance in the Ixodid Tick Dermacentor Andersoni

1973 ◽  
Vol 58 (2) ◽  
pp. 549-564
Author(s):  
W. R. KAUFMAN ◽  
J. E. PHILLIPS
Keyword(s):  
Salivary Gland ◽  
Fluid Secretion ◽  
Ixodid Tick ◽  
Artificial Medium ◽  
Salivary Duct ◽  
Bathing Medium ◽  
Dermacentor Andersoni ◽  
Cl Secretion ◽  
Wide Range

1. The salivary gland of the ixodid tick, Dermacentor andersoni, can be induced to secrete fluid for at least 6 h when bathed in an artificial medium in vitro. 2. Fluid secretion appears to be a consequence of active Cl secretion since (a) it is inhibited by 95% when nitrate and by 100% when acetate replaces Cl in the bathing medium; however, bromide can support secretion as well as Cl, (b) the rates of fluid and Cl secretion are linearly related to the concentration of Cl in the medium; and (c) the S/H ratio for Cl is greater than unity at all concentrations despite a transacinar P.D. of 35 mV (lumen negative). 3. Although (in the presence of Na) a low concentration of K in the bathing medium stimulates the rate of fluid secretion fivefold, higher concentrations of K inhibit fluid secretion. The latter is largely due to a direct effect of K ion and not simply to increased osmotic pressure or reduced Na concentration. Fluid secretion is completely in hibited by 10-6 M ouabain. On the basis of these observations we propose that fluid secretion may be dependent on a Na-K activated ‘pump ATPase’, which is somehow involved in cation secretion. The S/H ratios of Na and K are greater than unity at all medium concentrations. 4. The saliva secreted in vitro is slightly hypo-osmotic to the bathing medium over a wide range of medium concentration (300-920 mOsm/l). We postulate that the primary saliva is iso- or hyper-osmotic to the bathing medium; the final elaborated saliva is probably rendered hypo-osmotic by a process of solute reabsorption somewhere between the acini and the orifice of the main salivary duct.

scholarly journals Molecular Mechanism of Pancreatic and Salivary Gland Fluid and HCO3−Secretion

2012 ◽  
Vol 92 (1) ◽  
pp. 39-74 ◽  
Author(s):  
Min Goo Lee ◽  
Ehud Ohana ◽  
Hyun Woo Park ◽  
Dongki Yang ◽  
Shmuel Muallem
Keyword(s):  
Salivary Glands ◽  
Molecular Mechanism ◽  
Acinar Cells ◽  
Duct Cell ◽  
Fluid Secretion ◽  
Relative Volume ◽  
Electrolyte Composition ◽  
Cell Functions ◽  
Secretory Glands ◽  
High Concentrations

Fluid and HCO3−secretion is a vital function of all epithelia and is required for the survival of the tissue. Aberrant fluid and HCO3−secretion is associated with many epithelial diseases, such as cystic fibrosis, pancreatitis, Sjögren's syndrome, and other epithelial inflammatory and autoimmune diseases. Significant progress has been made over the last 20 years in our understanding of epithelial fluid and HCO3−secretion, in particular by secretory glands. Fluid and HCO3−secretion by secretory glands is a two-step process. Acinar cells secrete isotonic fluid in which the major salt is NaCl. Subsequently, the duct modifies the volume and electrolyte composition of the fluid to absorb the Cl−and secrete HCO3−. The relative volume secreted by acinar and duct cells and modification of electrolyte composition of the secreted fluids varies among secretory glands to meet their physiological functions. In the pancreas, acinar cells secrete a small amount of NaCl-rich fluid, while the duct absorbs the Cl−and secretes HCO3−and the bulk of the fluid in the pancreatic juice. Fluid secretion appears to be driven by active HCO3−secretion. In the salivary glands, acinar cells secrete the bulk of the fluid in the saliva that is driven by active Cl−secretion and contains high concentrations of Na+and Cl−. The salivary glands duct absorbs both the Na+and Cl−and secretes K+and HCO3−. In this review, we focus on the molecular mechanism of fluid and HCO3−secretion by the pancreas and salivary glands, to highlight the similarities of the fundamental mechanisms of acinar and duct cell functions, and to point out the differences to meet gland-specific secretions.

Neural pathways mediating salivary fluid secretion in the ixodid tick Amblyomma hebraeum

1983 ◽  
Vol 61 (9) ◽  
pp. 1976-1980 ◽  
Author(s):  
W. R. Kaufman ◽  
R. A. Harris
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Fluid Secretion ◽  
Ixodid Tick ◽  
Ixodid Ticks ◽  
Sensory Receptor ◽  
Neural Pathways ◽  
Amblyomma Hebraeum ◽  
The Central Nervous System ◽  
Cholinomimetic Drugs

In ixodid ticks, the salivary glands are innervated by at least two nerves: one arising from the so called lateral plexus (SGNlp) and one arising as a branch of the palpal nerve (SGNpn). The injection of cholinomimetic drugs or large volumes of isosmotic saline into the haemocoel is known to stimulate salivary fluid secretion. The object of this study was to determine which nerves mediate the latter responses. We challenged ticks with either carbachol or isosmotic saline after cutting various nerves bilaterally. Cutting the SGNlp attenuated both carbachol-induced and saline-induced secretion. Cutting the opisthosomal nerves attenuated only saline-induced secretion. Cutting the SGNpn appeared to inhibit salivation in a nonspecific manner. The data indicate that saline-induced salivation is mediated by a sensory receptor located in the opisthosoma, whereas carbachol exerts its effect either in the central nervous system or via a sensory receptor located in the cephalothorax.

The effect of five fasciolicides on malate dehydrogenase activity and mortality of Fasciola gigantica, Fasciolopsis buski and Paramphistomum explanatum

1981 ◽  
Vol 55 (2) ◽  
pp. 115-122 ◽  
Author(s):  
A. J. Probert ◽  
R. K. Sharma ◽  
K. Singh ◽  
R. Saxena
Keyword(s):  
Enzyme Activity ◽  
Dehydrogenase Activity ◽  
Malate Dehydrogenase ◽  
Fasciola Gigantica ◽  
High Concentrations ◽  
Fasciolopsis Buski ◽  
Reduced Activity ◽  
Inhibited Enzyme ◽  
Malate Oxidation

ABSTRACTThe effect of oxyclozanide, hexachlorophene, nitroxynil, rafoxanide and diamphenethide on malate dehydrogenase activity of homogenates of Fasciola gigantica, Fasciolopsis buski and Paramphistomum explanatum was investigated. The ratio of oxaloacetate reduction to malate oxidation in homogenates of Fasciola gigantica, Fasciolopsis buski and P. explanatum was 4·5:1, 3·6:1 and 5·2:1 respectively. Oxyclozanide and rafoxanide at 10−3 M inhibited enzyme activity by 100% in homogenates from all three species while hexachlorophene at 10−3M also caused 100% inhibition in homogenates from Fasciola gigantica and P. explanatum but only 65% of malate oxidation in Fasciolopsis buski homogenates. Nitroxynil at 10−3M produced 60% inhibition in F. buski homogenates yet had little effect at this concentration on preparations from the other species. Little inhibition was seen with diamphenethide, even at high concentrations. Rapid death of Fasicola gigantica and P. explanatum resulted in vitro when 10−3M oxyclozanide, hexachlorophene, nitroxynil or rafoxanide, were added to the incubation medium. Fasciolopsis buski was killed by 10−3M oxyclozanide but at this concentration the remaining compounds only caused reduced activity. Assay of malate dehydrogenase following drug treatment in vitro failed to show any appreciable reduction in enzyme activity in Fasciola gigantica and P. explanatum but oxyclozanide and hexachlorophene produced inhibition in Fasciolopsis buski. The mode of action of these compounds is discussed.

scholarly journals 3-Nitropropionic acid oxidase from horseshoe vetch (Hippocrepis comosa): a novel plant enzyme

1999 ◽  
Vol 340 (2) ◽  
pp. 491-495 ◽  
Author(s):  
Charles R. HIPKIN ◽  
Mansour A. SALEM ◽  
Deborah SIMPSON ◽  
Stephen J. WAINWRIGHT
Keyword(s):  
Enzyme Activity ◽  
Acid Oxidase ◽  
Leaf Extracts ◽  
Nitropropionic Acid ◽  
A Subunit ◽  
High Concentrations ◽  
Nitrate And Nitrite ◽  
Plant Enzyme ◽  
3 Nitropropionic Acid

A novel enzyme that catalyses the oxygen-dependent oxidation of 3-nitropropionic acid (3NPA) to malonate semialdehyde, nitrate, nitrite and H2O2 has been purified from leaf extracts of the horseshoe vetch, Hippocrepis comosa, and named 3NPA oxidase. The enzyme is a flavoprotein with a subunit molecular mass of 36 kDa containing 1 molecule of FMN and exhibits little specificity for all nitroalkanes tested other than 3NPA (apparent Km 620 μM). The maximum enzyme activity in vitro was expressed at pH 4.8 and was inhibited strongly by the products nitrate and nitrite. 3NPA oxidase activity was detected in green shoots, which also contain high concentrations of 3NPA, from plants grown with nitrate, ammonium or N2 as sources of nitrogen. Enzyme activity was absent from roots and cell cultures, neither of which accumulate high levels of 3NPA.

scholarly journals Enterotoxicity and Cytotoxicity of Vibrio parahaemolyticus Thermostable Direct Hemolysin in In Vitro Systems

2000 ◽  
Vol 68 (6) ◽  
pp. 3180-3185 ◽  
Author(s):  
Francesco Raimondi ◽  
Joseph P. Y. Kao ◽  
Carla Fiorentini ◽  
Alessia Fabbri ◽  
Gianfranco Donelli ◽  
...  
Keyword(s):  
Vibrio Parahaemolyticus ◽  
Fluid Secretion ◽  
Cell Types ◽  
Chloride Secretion ◽  
Free Calcium ◽  
Thermostable Direct Hemolysin ◽  
High Concentrations ◽  
Intestinal Fluid Secretion ◽  
Dose Dependent

ABSTRACT Vibrio parahaemolyticus is a marine bacterium known to be a common cause of seafood gastroenteritis worldwide. The thermostable direct hemolysin (TDH) has been proposed to be a major virulence factor of V. parahaemolyticus. TDH causes intestinal fluid secretion as well as cytotoxicity in a variety of cell types. In this study, we investigated the interplay between the hemolysin's enterotoxic and cytotoxic effects by using both human and rat cell monolayers. As revealed by microspectrofluorimetry, the toxin causes a dose-dependent increase in intracellular free calcium in both Caco-2 and IEC-6 cells. This effect was reversible only when low toxin concentrations were tested. The TDH-activated ion influx pathway is not selective for calcium but admits ions such sodium and manganese as well. Furthermore, in the same range of concentration, the hemolysin triggers a calcium-dependent chloride secretion. At high concentrations, TDH induces a dose-dependent but calcium-independent cell death as assessed by functional, biochemical, and morphological assays.

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