Paul M. Toom

Utilization of body reserves for minim brood development by queens of the imported fire ant, Solenopsis invicta

Abstract Protein, glycogen, and lipid concentrations were followed in Solenopsis invicta queens, the imported fire ant, from egg deposition until the production of the first minim workers approximately 21 days later. During this time, the weight of the queens decreased from 14·7 to 7·5 mg. Immediately following egg deposition, total protein decreased by over 50 per cent for the first 6 days, then rose steadily for 9 days, then once again decreased markedly throughout the remainder of the study. Glycogen concentrations decreased rapidly from the 0·35 mg/ant found at oviposition until day 12. From this time until the end of the study, this polysaccharide remained constant at about 10 mg/ant. Lipid concentrations remained at 4·1 mg/ant for the first 9 days following oviposition, then steadily decreased to 2·3 mg/ant when the first minim workers were produced 12 days later.

Preliminary studies of nematocysts from the jellyfish Stomolophus meleagris

Abstract Nematocysts from the jellyfish Stomolophus meleagris were found to be of the type—heterotrichous microbasic euryteles. The nematocysts were not ruptured by various physical or chemical means, but were disrupted by homogenization in a Braun homogenizing mill. The toxin(s) which contained 11·2 per cent protein and 7·25 per cent nitrogen, had an LD50 in mice of 0·85 μg N2/g mouse when injected intravenously. The toxin(s) were heat labile and rapidly destroyed when incubated with trypsin, indicating that they were protein.

Enzymatic activities of venom from the jellyfishStomolophus meleagris

Abstract 1. Lyophilized venom from the nematocysts of the jellyfish Stomolophus meleagris was tested for enzymatic activity on twenty-eight substrates commonly hydrolyzed by many animal toxins. 2. Of the twenty-eight substrates tested, twelve were hydrolyzed. The hydrolysis of these twelve substrates suggests the presence of 5′-nucleotidase, hyaluronidase, phosphatase (both acid and alkaline), phosphodiesterase, leucine aminopeptidase and proteases. 3. A comparison of the enzymatic nature of the venom with other animal toxins (especially snake venoms) is made.

Effects of purified components of jellyfish toxin (Stomolophus meleagris) on active sodium transport

Abstract Using preparative isoelectric focusing and discontinuous membrane partition chromatography, three fractions which alter sodium transport were isolated from venom of the jellyfish Stomolophus meleagris . A fraction which inhibited sodium transport was partially purified and found to possess a molecular weight of approximately 50,000 and an isoelectric point of 3·30. This component, which appeared to affect active sodium transport at the enzyme level, was also found to produce hemorrhage and necrosis in mice. Two fractions were purified which increased sodium transport in a passive manner and possessed molecular weights of 10,000–50,000, and greater than 300,000, respectively, and have isoelectric points of 4·15 and 5·30. The fraction of 300,000 mol. wt contained most of the toxicity. It is concluded that the immediate pharmacological response to jellyfish toxin possibly is due to components which increase sodium transport, while the apparent delayed response is probably due to a component of the toxin which acts in a cardiotonic, ouabain-like manner.

Cardiac effects of Stomolophus meleagris (cabbage head jellyfish) toxin.

Abstract Electrocardiograms recorded from rabbits and rats injected intravenously with toxin from Stomolophus meleagris showed bradycardia followed by inversion of the P and T waves, alterations of the QRS complex, ventricular extrasystoles, atrioventricular block, bizarre ventricular patterns, and fibrillation. Analysis of plasma samples taken after the onset of electrocardiographic abnormalities were characterized by hemolysis, hyponatremia and hyperkalemia when compared to plasma taken before injection of toxin. Sublethal doses of toxin produced an increase in lactate dehydrogenase (LDH) levels in serum, but did not increase creatine phosphokinase levels. Electrophoretic analysis of the serum LDH isoenzymes following injection of toxin did not indicate severe cardiac tissue damage. This toxin appears to disrupt cardiac rhythmicity and myocardial conduction pathways in a manner consistent with other coelenterate toxins. The observed hyperkalemia appears to result from hemolysis and generalized tissue destruction, although the serum enzyme and isoenzyme assays did not suggest severe myocardial infarction.

Amino acid changes in newly inseminated queens of Solenopsis invicta

Abstract The amino acid composition of both free and protein bound amino acids from haemolymph of newly inseminated queens of Solenopsis invicta , the red imported fire ant, was determined at 10-hr intervals following forced copulation. Valine, proline, serine, threonine, arginine, and lysine were found in the highest concentrations while tyrosine, aspartic acid, glutamic acid, and methionine were present in the smallest quantities. The total amino acid concentration of 2600 mg/100 ml haemolymph was almost equally divided between free and protein bound amino acids. During the first 20 hr following insemination, those amino acids which occur in higher concentration in the flight muscles than haemolymph increased rapidly in the free amino acid fraction of the haemolymph, thus indicating that flight muscle histolysis is initiated immediately following insemination, with the breakdown products being made available for colony founding.

Effects of purified components of jellyfish toxin (Stomolophus melleagris) on adenosine triphosphatase activities

Abstract Toxin from the jellyfish Stomolophus meleagris was found to stimulate both Na + -K + and mitochondrial Mg 2+ ATPase activities at low toxin concentrations and to inhibit these ATPase activities at higher (> 0·2 mg/ml) concentrations. Using discontinuous membrane partition chromatography the toxin was fractionated into six fractions. Of these six fractions, one strongly activated when five inhibited mitochondrial Mg 2+ ATPase. One fraction strongly activated, a second mildly activated, while the other four inhibited Na + -K + ATPase about 50 per cent. Only two fractions affected oligomycin-insensitive ATPase, and both of these exhibited a mild stimulation. It is concluded that the ability of this toxin to alter membrane permeability to Na + is due, at least in part, to components in the toxin which act directly on ATPase.

Procedure for selecting monoclonal antibodies for use in a ligand displacement assay of serum antibody levels

Monoclonal antibodies for use in a ligand displacement assay were selected for specificity and affinity/avidity properties that result in their release and displacement in the presence of specific sample antibody but not in the presence of antibodies against other antigens. A screening process is described which involves measurement of displacement of antibody by an ELISA procedure using an enzyme labeled anti-immunoglobulin, providing a means of demonstrating usefulness of a candidate antibody in a ligand displacement format without necessitating the production of enzyme conjugates of each candidate antibody to be screened. The procedure was used to screen a set of eleven monoclonal antibodies (initially selected for anti-Trichinella spiralis specificity by conventional screening methods), and successfully discriminated between antibodies which were useful in the ligand displacement format and those which were not.

Protein and lactate dehydrogenase levels in Aedes aegypti

Lactate dehydrogenase (LDH) and total protein concentrations of adult female Aedes aegypti were determined following emergence from the pupal cuticle through a period of 20 days, during which time 2 blood meals were taken. Preceding the blood meal, LDH exhibited distinct peaks 5 and 10 days following emergence. LDH activity remained constant for 2 hr following a blood meal, then rose rapidly to a value 10 times pre-blood meal values 7 hr after feeding. This activity then steadily declined to reach pre-blood meal values within 72 hr. This pattern was repeated in mosquitoes given a second blood meal as well as in virgin mosquitoes taking blood, suggesting that the blood meal stimulates either the synthesis or activation of LDH.

Evaluation of specific binding affinity and biochemical properties of fish eye-lens reagents from seven teleost species

Abstract 1. 1. Eye-lens proteins from seven teleost species were extracted and processed to produce modifications conferring specific binding affinity for selected molecules or cellular antigens. Specifically active reagents were obtained from two of the species utilized. 2. 2. Eye-lens preparations contained several positively charged subunits, with the predominant subunit having a mol. wt of approx. 20,000. 3. 3. Of a number of assay methods evaluated the passive hemagglutination test best assessed specific binding properties of eye-lens reagents. 4. 4. The best specific binding activity was demonstrated for soluble protein molecules (e.g. rabbit IgG), with weak or no binding activity demonstrated for polysaccharide or cell-associated structures.