The biological half life and distribution of 125Iodide and radioiodinated protein in the imported fire ant, Solenopsis invicta

The radioisotope ¹²⁵Iodide, a gamma emittor, was used in two different forms, as ¹²⁵I mixed with egg yolk and as ¹²⁵I covalently attached to egg albumin and mixed with egg yolk, to study food flow in the imported fire ant, Solenopsis invicta Buren. The biological half life of ¹²⁵I-albumin in egg yolk powder was determined to be 96 hr in isolated workers, 108 hr in individuals held with small groups of unlabelled workers, and 1,008 hr in workers held in colonies exposed to labelled food for 48 hr. In contrast, the biological half life of free ¹²⁵I mixed with egg yolk powder was 22 hr, 20 hr, and 40 hr, respectively.The internal distribution of radioactivity was checked after 24,48, and 380 hr. There was a significant difference in distribution of ¹²⁵I in ants fed either free ¹²⁵I or ¹²⁵I-albumin. Most of the free ¹²⁵I was rapidly excreted. A high percentage of ¹²⁵I-albumin was assimilated, apparently through protein digestion pathways with eventual storage in or below the cuticle. There was no evidence of gland involvement in food flow to either larvae or queens with the radio-iodinated protein.

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Résumé L'utilisation de l'iode radio-actif (¹²⁵I) a permis d'étudier le cheminement de la nourriture chez Solenopsis invicta Buren (Myrmicinée). Deux formes différentes de l'isotope ont été étudiées. L'iode 125 a été fixé d'une manière covalente à la tyrosine dans l'albumine des oeufs en utilisant la méthode chloramine T pour ioder les protéines. L'albumine marquée a été mangée ensuite à du jaune d'oeuf en poudre.La seconde forme contenait de l'iode 125 mélangé au jaune d'oeuf en poudre en absence de tout catalyseur, ce qui empêche la fixation chimique. La demi-vie biologique (T_biol) des deux formes a été déterminée chez des ouvrières isolées, chez des individus gardés avec de petits groupes d'ouvrières non-marquées, et chez des ouvrières gardées dans des colonies exposées à la nourriture radio-active pendant 48 h. La demi-vie biologique de l'albumine marquée était de 96 h, 108 h, et 1.008 h. En contraste, la demi-vie de l'iode 125 était de 22 h, 20 h, et 40 h. L'effet de groupe créé par des échanges répétés de nourriture entre les individus était négligeable avec la nourriture protéique. L'échange répété de nourriture entre les larves et les ouvrières a beaucoup augmenté la demi-vie de l'albumine marquée à I 125. Cet effet n'était pas aussi clair avec l'iode 125 par suite de son élimination rapide.La distribution de la radio-activité a été examinée chez des ouvrières au bout de 24, 48 et 380 h après les avoir nourries avec de l'albumine marquée à I 125 et de l'iode 125. Il y avait une différence considérable de distribution, avec un haut pourcentage d'albumine assimilé, sans doute par les voies de digestion de protéines. Le radio-isotope a été ensuite conservé sous forme d'iode 125 ou d'iodotyrosine, dans (ou sous) la cuticule de l'ensemble du corps. Les fourmis ont rapidement excrété l'iode 125 libre avec 5% de la radioactivité résiduelle après 380 h, peut-être fixée aux protéines cellulaires, et ensuite transportée vers la cuticule. Les différences considérables entre les demi-vies biologiques et la distribution interne de la radioactivité chez les fourmis nourries avec de l'iode 125 ou à l'albumine marquée à I 125, soulignent le danger de croire que le cheminement de la nourriture peut être définitivement étudié en utilisant des radio-isotopes qui ne sont pas fixés chimiquement à la substance étudiée.

     

The labial gland system of larvae of the imported fire ant,Solenopsis invicta Buren

Summary The authors describe the ultrastructure of the labial gland system in imported fire ant larvae, Solenopsis invicta Buren and present an enzyme analysis of enzymes in labial-gland secretions and midgut contents. The tubes of the labial gland produce and secrete a proteinaceous substance rich in digestive enzymes. The narrow cells of the reservoir of the gland have little or no secretory function but the lumen stores the proteinaceous secretion. The labial-gland enzymes include proteases and amylases, which function in extraintestinal digestion of solid food placed on the anteroventral body region of 4th-instar larvae by adult workers. The midgut contains proteases, amylases, and upases. Lipids appear to be predigested by the workers before being fed to the larvae.Approved as TA 15262 by the Director of the Texas Agricultural Experiment Station in cooperation with ARS/USDA. Supported by the Texas Department of Agriculure interagency agreement IAC-0487 (78-79)We would like to thank Rosemary Kamas, Dr. John Mirenda, and Mike Strand for their help in dissections of larvae and Dr. Howard Williams for his advice and suggestions     

Host discrimination byChelonus insularis [Hym.: Braconidae], telenomus heliothidis [Hym.: Scelionidae], andTrichogramma pretiosum [Hym.: Trichogrammatidae]

The ability of female parasitoids (Chelonus insularis Cresson,Telenomus heliothidis Ashmead, andTrichogramma pretiosum Riley) to distinguish between parasitized and unparasitized tobacco budworm,Heliothis virescens (F.), eggs was determined in laboratory studies. All 3 species were relatively efficient at detecting eggs that were previously parasitized by conspecific females.T. heliothidis andT. pretiosum were able to discriminate on the basis of external examination of host eggs, whereasC. insularis appeared to examine hosts internally as well as externally. In interspecific tests, no species readily rejected eggs parasitized by the other 2 species.     

Molecular Structure of Frizzled, a Drosophila Tissue Polarity Gene

The function of the frizzled (fz) locus is required to coordinate the cytoskeletons of pupal epidermal cells so that a parallel array of cuticular hairs and bristles is produced. We report here the molecular cloning and characterization of the fz locus. The locus is very large. Mutations that inactivate the gene are spread over 100 kb of genomic DNA. The major mRNA product of the gene is a 4-kb RNA that is encoded by 5 exons spread over more than 90 kb of genomic DNA. Conceptual translation of this mRNA indicates that it encodes an integral membrane protein that is likely to contain both extracellular and cytoplasmic domains.     

Dopaminergic control of aldosterone: modulation of the response of rat adrenal zona glomerulosa cells to alpha-Msh by pretreatment with bromocriptine or metoclopramide

Bromocriptine treatment in rats (3 mg/kg per day, 7 days) significantly reduced alpha-msh and aldosterone plasma levels 2 hrs after the final treatment in animals on low, normal and high sodium diets. Alpha-MSH dose response curves for corticosterone and 18-hydroxydeoxycorticosterone (18-OH-DOC) in subsequently incubated glomerulosa cells gave stimulation at lower concentrations of alpha-MSH (10(-10) moles per litre) than in cells from untreated animals (10(-9) moles per 1). Curves for aldosterone (ald) and 18-hydroxycorticosterone (18-OH-B) were also affected in cells from animals on a low sodium diet. Fasciculata-reticularis cell responses to ACTH were unaffected. Metoclopramide (4 mg/kg per day, 7 days) elevated plasma alpha-MSH, although ald was unaffected, but inhibited the glomerulosa cell response to alpha-MSH in vitro. Acute dopaminergic responses in plasma ald may be mediated through alpha-MSH in rats, but chronically alpha-MSH may down- regulate glomerulosa cell alpha-MSH receptors. It is unlikely that alpha-MSH mediates the adrenocortical response to sodium depletion.     

Duality and developmental changes of chicken thymus. DNA ligases

Chick embryo DNA ligases occur in two forms in the thymus. The first form is a heavy molecule with a molecular weight of 165 000; the second has a molecular weight of 82 000. Developmental studies of the sucrose gradient and phosphocellulose extract of thymus show that the heavy enzyme persists until the day of hatching and the light molecular weight enzyme appears at birth. The possible involvement of these forms in differentiation and repair is discussed. Also discussed is the significance of this change with regard to the hormonal development of the chicken embryo and of the chicken.     

Impact of the invasion of the imported fire ant

The impact of the imported fire ant (IFA) is complex, in large part, because several very different species of “Fire Ants” have invaded and one of these has two forms, all of which are hard to separate by the public, as well as, some investigators not focused on the ant. Each of these different “IFA” species and forms differ in their impact. Further, these ants impact a number of “things” ranging from the environment and wildlife (plants and animals) as well as people, their environment and infrastructure. In addition, they can not only lead to death of living things (including people), but they can destroy many aspects of our environment and infrastructure at the cost of millions of dollars. But there are some beneficial aspects and some people can make many thousands of dollars due to their presence. This is an attempt to look at these issues.