The Retention of Amino Acids in the Haemolymph During Diuresis in Rhodnius

1980 ◽  
Vol 87 (1) ◽  
pp. 315-330
Author(s):  
S.H.P. MADDRELL ◽  
B.O.C. GARDINER
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Fluid Secretion ◽  
Malpighian Tubules ◽  
High Rate ◽  
Excretory System ◽  
Low Permeability ◽  
High Concentrations ◽  
Active Reabsorption ◽  
Very High

The haemolymph of Rhodnius is rich in amino acids. During the rapid diuresis after a blood meal, no more than trace amounts of amino acids are lost in the urine. There is no significant reabsorption of amino acids in the excretory system. That they escape elimination can instead be attributed to a combination of the low permeability of the Malpighian tubules to amino acids, the very high rate of fluid secretion by the tubules, and the dilution of the haemolymph by an expansion in its volume after feeding. Amino acid losses are low in spite of the fact that the tubules actively accumulate high concentrations of amino acids in their cells and passive losses from these stores augment to some extent the flux of amino acids into the lumen. At times other than during diuresis, fluid secretion by the Malpighian tubules is slow. Calculations show that haemolymph solutes can then passively reach the higher concentrations in the lumen that are required for the operation of the excretory system (which relies on unselective passive entry and active reabsorption of useful substances). An advantage of the extraordinarily high rate of fluid secretion during diuresis is that fluid excretion can be rapidly completed. There is then little time for significant amounts of haemolymph solute to be lost passively.

The initial stages in the action of an insecticidal delta-endotoxin of Bacillus thuringiensis var. israelensis on the epithelial cells of the malpighian tubules of the insect, Rhodnius prolixus

1988 ◽  
Vol 90 (1) ◽  
pp. 131-144
Author(s):  
S.H. Maddrell ◽  
N.J. Lane ◽  
J.B. Harrison ◽  
J.A. Overton ◽  
R.B. Moreton
Keyword(s):  
Bacillus Thuringiensis ◽  
Intercellular Junctions ◽  
Fluid Secretion ◽  
Malpighian Tubules ◽  
Ultrastructural Changes ◽  
Cytoplasmic Vacuolization ◽  
Large Numbers ◽  
Delta Endotoxin ◽  
High Concentrations ◽  
Very High

The effects of the 27 X 10(3) Mr insecticidal delta-endotoxin from Bacillus thuringiensis var. israelensis have been studied using, as a model system, isolated insect Malpighian tubules. At all concentrations of the toxin higher than 1 microgram ml-1 (4 X 10(−8) moll-1) applied to the outer surface of the tubules, fluid secretion failed within about 30 min. Except at very high concentrations, where failure always takes at least 30 s, there was an inverse relationship between the concentration of toxin and the time of failure of toxin-treated tubules. During exposure to toxin, the tubules were initially unaffected for a relatively long period and then rapid failure occurred. If the tubules were removed into toxin-free saline just before failure would have occurred, fluid secretion remained normal for at least 2 h, but on return to the origin toxin-containing saline failure was almost immediate. The toxin was found not to bind to the basement membrane. Ultrastructural changes became evident as tubule failure occurred. These initially involved modifications to the basal side of the cells, but later also to the luminal microvilli. Intercellular junctions became disassociated and cytoplasmic vacuolization occurred. The population of intramembranous particles in the basal membranes became reduced with time. Our findings suggest the following hypothesis for the initial stages in the interaction of the toxin with the tubules. Toxin molecules attach to the accessible cell membranes progressively and irreversibly. They do not readily associate by diffusing laterally in the membrane, so that toxic effects develop only when sufficiently large numbers of them attach close together. The molecules may then associate in some way as a complex, perhaps forming a pore in the membrane. Relatively few such pores lead rapidly to cell failure and death.

scholarly journals A Preliminary Report on the Use of Bench-Top X-Ray Micro-Computerised Tomography to Study the Malpighian Tubules of the Overwintering Seven Spotted LadybirdCoccinella septempunctataL. (Coleoptera: Coccinellidae)

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Duncan Bell ◽  
Lewis Woolnough ◽  
David Mortimore ◽  
Nick Corps ◽  
Diana M. Hudson ◽  
...  
Keyword(s):  
Coccinella Septempunctata ◽  
Ct Scanning ◽  
Small Sample ◽  
Malpighian Tubules ◽  
Micro Ct ◽  
Computerised Tomography ◽  
X Ray ◽  
High Concentrations ◽  
Very High ◽  
Metallic Pollutants

The application of micro-CT scanning techniques on a small sample of “Seven-spot ladybirds”Coccinella septempunctata,collected in December 2009, identified an accumulation of material with a very high, relative X-ray attenuation value in the malpighian tubules of most but not all of the individuals sampled. The passage of metals such as cadmium in soil through a food chain to finally accumulate in high concentrations in ladybirds and lacewings has been previously reported. The identification of the dense material found in our sample of ladybirds, its origin, and the process by which it accumulates in, and is processed by, the malpighian tubules is the challenge ahead. The authors speculate that a straightforward means of monitoring levels of metallic pollutants in the environment might emerge.

Amino acid uptake systems in Bacteroides ruminicola

1979 ◽  
Vol 25 (10) ◽  
pp. 1161-1168 ◽  
Author(s):  
Roselynn M. W. Stevenson
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Nitrogen Sources ◽  
Amino Acid Uptake ◽  
Defined Medium ◽  
High Rate ◽  
Transport Systems ◽  
Acid Uptake ◽  
Chemical Structures ◽  
Kinetic Inhibition

Uptake of amino acids by Bacteroides ruminicola was observed in cells grown in a complete defined medium, containing ammonia as the nitrogen source. A high rate of uptake occurred only in fresh medium, as an inhibitory substance, possibly acetate, apparently accumulated during growth. All amino acids except proline were taken up and incorporated into cold trichloroacetic acid precipitable material. Different patterns of incorporation and different responses to 2,4-dinitrophenol and potassium ferricyanide indicated multiple uptake systems were involved. Kinetic inhibition patterns suggested six distinct systems were present for amino acid uptake, with specificities related to the chemical structures of the amino acids. Thus, the failure of free amino acids to act as sole nitrogen sources for growth of B. ruminicola is not due to the absence of transport systems for these compounds.

Effect of fertilization on free amino acid concentrations in black spruce and jack pine containerized seedlings

1987 ◽  
Vol 17 (1) ◽  
pp. 27-30 ◽  
Author(s):  
Y. T. Kim ◽  
C. Glerum ◽  
J. Stoddart ◽  
S. J. Colombo
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acid ◽  
Free Amino ◽  
Black Spruce ◽  
Jack Pine ◽  
Foliar Nitrogen ◽  
Containerized Seedlings ◽  
High Concentrations ◽  
Amino Acid Concentrations

Greenhouse-grown black spruce and jack pine container seedlings were fertilized weekly with a 20–8–20 fertilizer at four concentrations during the fall. Seedlings were sampled when 23 weeks old towards the end of the greenhouse cultural period to determine the effect of fertilization on the free amino acid concentrations. All amino acids, except tryptophan, showed significant increases in concentration with higher levels of fertilizer; the concentration of tryptophan decreased with increasing fertilizer concentration. Amino acids with the highest concentrations in black spruce were arginine, glutamic acid, and proline, while in jack pine, besides these three, aspartic acid and glutamine were also found in high concentrations. Black spruce had significantly higher amino acid concentrations than jack pine. The concentrations of certain free amino acids may be more sensitive indicators of seedling nitrogen status than total foliar nitrogen.

scholarly journals Turnover as a control of ribonucleic acid accumulation in bacteria undergoing stepdown

1976 ◽  
Vol 154 (2) ◽  
pp. 541-552
Author(s):  
J E. M. Midgley
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Turnover Rate ◽  
Amino Acid Starvation ◽  
High Rate ◽  
Glucose Medium ◽  
Amino Acid Deprivation ◽  
Acid Accumulation ◽  
Associated Proteins ◽  
Kinetics Of

The synthesis of ribosomes was compared in rel+ and rel- strains of Escherichia coli undergoing “stepdown” in growth from glucose medium to one with lactate as principal carbon source. Two strains (CP78 and CP79), isogenic except for rel, showed similar behaviour with respect to (1) the kinetics of labelling total RNA and ribosomes with exogenous uracil, (2) the proportion of newly formed protein that could be bound with nascent rRNA in mature ribosomes, and (3) the rate of induction of enzymically active β-galactosidase (relative to the rate of ribosome synthesis). It was concluded that, as there was no net accumulation of RNA during stepdown in either strain, rRNA turnover must be occurring at a high rate. The general features of ribosome maturation in rel+ and rel- cells were almost identical with those found in auxotrophic rel+ organisms starved of required amino acids. In both cases, there was a considerable delay in the maturation of new ribosomal particles, owing to a relative shortfall in the rate of synthesis of ribosome-associated proteins. Only about 4-5% of the total protein labelled during stepdown was capable of binding with newly formed rRNA. This compared with 3.5% for rel+ and 0.5% for rel- auxotrophs during amino acid starvation. The turnover rate for newly formed mRNA and rRNA was virtually the same in “stepped-down” rel+ and rel- strains and was similar to that of the same fraction in amino acid-starved rel+ cells. The functional lifetime of mRNA was also identical. It seems that in the rel- strain many of the characteristics typical of the isogenic rel+ strain are displayed under these conditions, at least as regards the speed of ribosome maturation and the induction of β-galactosidase. Studies on the thermolability of the latter enzyme induced during stepdown indicate that inaccurate translation, which occurs in rel- strains starved for only a few amino acids, is less evident in this situation than in straightforward amino acid deprivation.

Suppression of muscle protein turnover and amino acid degradation by dietary protein deficiency

1992 ◽  
Vol 263 (2) ◽  
pp. E317-E325 ◽  
Author(s):  
N. E. Tawa ◽  
A. L. Goldberg
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Dietary Protein ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Normal Diet ◽  
High Rate ◽  
Acid Uptake ◽  
Rapid Weight Gain

To define the adaptations that conserve amino acids and muscle protein when dietary protein intake is inadequate, rats (60-70 g final wt) were fed a normal or protein-deficient (PD) diet (18 or 1% lactalbumin), and their muscles were studied in vitro. After 7 days on the PD diet, both protein degradation and synthesis fell 30-40% in skeletal muscles and atria. This fall in proteolysis did not result from reduced amino acid supply to the muscle and preceded any clear decrease in plasma amino acids. Oxidation of branched-chain amino acids, glutamine and alanine synthesis, and uptake of alpha-aminoisobutyrate also fell by 30-50% in muscles and adipose tissue of PD rats. After 1 day on the PD diet, muscle protein synthesis and amino acid uptake decreased by 25-40%, and after 3 days proteolysis and leucine oxidation fell 30-45%. Upon refeeding with the normal diet, protein synthesis also rose more rapidly (+30% by 1 day) than proteolysis, which increased significantly after 3 days (+60%). These different time courses suggest distinct endocrine signals for these responses. The high rate of protein synthesis and low rate of proteolysis during the first 3 days of refeeding a normal diet to PD rats contributes to the rapid weight gain ("catch-up growth") of such animals.

Adaptational changes in Staphylococcus aureus MF31 grown above its maximum temperature when protected by NaCl: physiological studies

1984 ◽  
Vol 30 (9) ◽  
pp. 1105-1111 ◽  
Author(s):  
A. Hurst ◽  
Esther Ofori ◽  
A. A. El-Banna ◽  
J. Harwig
Keyword(s):  
Amino Acids ◽  
Staphylococcus Aureus ◽  
Amino Acid ◽  
Monosodium Glutamate ◽  
Amino Acid Pool ◽  
Maximum Temperature ◽  
C Cells ◽  
Acid Pool ◽  
High Concentrations ◽  
P Cells

Staphylococcus aureus MF31 can grow at 46 °C, 2 °C above its normal maximum temperature of growth if 1 M NaCl is added to the medium. In the present work we show that monosodium glutamate, proline, threonine, aspartic acid, and betaine (in order of decreasing effectiveness) also enabled cells to grow at 46 °C. Cells grown at 46 °C in he presence of salt (protected or P cells) accumulated glutamate more rapidly than cells grown at 37 °C without salt (normal or N cells) and contained an increased amino acid pool. The principal constituents of this pool were dicarboxylic amino acids and proline. Turbidimetric evidence suggests that NaCl caused plasmolysis in S. aureus. The P cells, although grown in 1 M NaCl, had about the same Cl− and K+ content as the N cells grown without added NaCl. P cells had increased heat resistance but high concentrations of CaCl2 in the heating menstruum reduced their D55 value from a maximum of 214 min to < 30 s. We suggest that growth at 46 °C in 1 M NaCl can be explained, in part at least, by the increased amino acid pool internal to the cell and the external osmotic support given by Cl− anions excluded by the cell.

Des acides aminés stimulateurs et inhibiteurs à la croissance de Corynebacterium sepedonicum (Spieck. et Kott., Skapt. et Burkh.) dans des milieux synthétiques

1978 ◽  
Vol 24 (9) ◽  
pp. 1087-1092
Author(s):  
G. J. Ikin ◽  
H. J. Hope ◽  
R. A. Lachance
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Ammonium Phosphate ◽  
Methionine Sulfoxide ◽  
High Rate ◽  
Molar Ratio ◽  
Corynebacterium Sepedonicum ◽  
Ring Rot ◽  
Acides Aminés ◽  
Synthetic Media

Some aspects of the growth and amino acid metabolism of Corynebacterium sepedonicum, the organism responsible for potato ring rot, have been studied in synthetic media. It has been demonstrated that organic sulfur is required for growth. Methionine supports growth and can be replaced by methionine sulfoxide and cystathionine. Methionine is a micrometabolite for this species as indicated by the fact that optimum growth can be obtained in an asparagines–methionine (asn-met) containing medium when the molar ratio of these amino acids is 56:1. Increasing the proportion of methionine does not increase the growth. Both asparagine and glutamine are metabolized very quickly and provide for equivalent rapid growth unlike aspartic and glutamic acids. In the case of the last two amino acids, growth can be increased if dibasic ammonium phosphate is added to the medium although this compound alone will not support growth in the culture medium. The intracellular soluble asparagine level is extremely low in cells from the asn-met medium indicating a high rate of metabolism compared to aspartic acid. Cystine and cysteine were found to be inhibitory to the organism: they do not affect the rate of uptake of asn or met but do alter the organism's metabolism as reflected by changes in the free amino acid pool. The concentrations of cystine and cysteine required for measurable inhibition are much higher than those found in soluble amino acids of potato tubers.

scholarly journals Cytochrome C and COI Sequence of O.laetus Review

2021 ◽  
Vol 9 (4) ◽  
Author(s):  
Mazhar MW ◽  
◽  
Raza A ◽  
Sikandar M ◽  
Mahmood J ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Cytochrome C ◽  
Amino Acid Sequence ◽  
Coi Gene ◽  
Accession Number ◽  
Protein Entry ◽  
Significant Match ◽  
Very High

The COI sequence of O.laetus was submitted to the Genbank database holding an accession number HQ908084 (Figure1). The amino acid sequence of the corresponding COI gene was also updated under the accession number ADZ05746, which turned out to contain 222 amino acids. Base statistics of the O.laetus COI are presented in Figure 2. It can be seen from the table that the fragment is rich in AT content as expected with thymine occurring most frequently followed by the others in the order A, C & G. The AT% stood at 67.2 in comparison to GC% at 32.8. The protein entry was subjected to family confirmation by searching the InterProScan database and the results indicate a very high and significant match confirming our sequence to be a part of Cytochrome C.

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