Gain and loss of fluid in metamorphosing larvae of Manduca sexta

Joesten, Michael E.; Royston, Moira E.; Jimenez, Marlene; Wadewitz, A. G.; Melian, Diana; Lockshin, Richard A.

doi:10.1016/0022-1910(82)90056-7

Cited by 6 publications

(2 citation statements)

References 18 publications

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“…Bar ϭ 1 mm. nonfibrous silk to line its burrow, into which it excretes voluminous quantities of an alkaline fluid [Joesten et al, 1982], which may function as a polymerizing agent. The importance to the story of cell death is that the abrupt decline in protein synthesis, as estimated by incorporation of methionine, includes, first, a substantial shift in the type of protein synthesized.…”

Section: Discussionmentioning

confidence: 99%

Protein synthesis, DNA degradation, and morphological changes during programmed cell death in labial glands ofManduca sexta

et al. 1997

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Labial glands of the tobacco hornworm Manduca sexta (Lepidoptera: Sphingiidae), homologues of Drosophila salivary glands, undergo programmed cell death (PCD) in a 4‐day period during larva‐to‐pupa metamorphosis. The programmed death of the labial gland was examined by electron microscopy and measurement of protein synthesis as well as measurement of DNA synthesis, end‐labeling of single strand breaks, and pulsed‐field gel electrophoresis. One of the earliest changes observed is a sharp drop in synthesis of most proteins, coupled with synthesis of a glycine‐rich protein, reminiscent of silk‐like proteins. From a morphological standpoint, during the earliest phases the most prominent changes are the formation of small autophagic vacuoles containing ribosomes and an apparent focal dissolution of the membranes of the endoplasmic reticulum, whereas later changes include differing destruction at the lumenal and basal surfaces of the cell and erosion of the basement membrane. By the fourth day of metamorphosis, individual cells become rapidly vacuolated in a cell‐independent manner. In the vacuolated cells on day 3, chromatin begins to coalesce. It is at this period that unequivocal nucleosomal ladders are seen and end‐labeling in situ or electrophoretic techniques document single or double‐strand breaks, respectively. DNA synthesis ceases shortly after the molt to the fifth instar, as detected by incorporation of tritiated thymidine and weak TUNEL labeling. Large size fragments of DNA are seen shortly after DNA synthesis ceases and thence throughout the instar, raising the possibility of potential limitations built into the cells before their final collapse. Dev. Genet. 21:249–257, 1997. © 1997 Wiley‐Liss, Inc.

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Section: Discussionmentioning

confidence: 99%

Protein synthesis, DNA degradation, and morphological changes during programmed cell death in labial glands ofManduca sexta

et al. 1997

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“…The unique behavior of hemocyte populations during the last larval stadium of M. sexta may reflect the special biology of this species. During its wandering stage, this species loses water from its hemolymph and produces copious salivary fluid that facilitates its boring through soil as a prelude to pupation (Reinecke et al, 1980;Joesten et al, 1982). Thus, hemolymph may serve as a water reservoir, with water accumulating in the hemolymph up to the wandering stage and with water being lost from the hemolymph during the wandering stage.…”

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Correlation of hemocyte counts with different developmental parameters during the last larval instar of the tobacco hornworm, Manduca sexta

Beetz

Holthusen

Koolman

et al. 2007

Arch Insect Biochem Physiol

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We determined the changes in hemocyte titer and in the abundance of hemocyte types of the tobacco hornworm Manduca sexta during the fourth and fifth larval stadium and the beginning of the pupal stadium. As we analyzed the samples of individual insects at daily intervals, we were able to correlate phenotypical features, body weight, as well as total protein content and lysozyme activity in the hemolymph with the observations on hemocytes. In the course of the fifth larval stadium, the hemocyte titer decreased slightly and declined further after pupation. Using calculated values for total hemocyte numbers, females had about five times and males three times more hemocytes in the circulating population at the beginning of the wandering stage (in the middle of the fifth larval stadium) than immediately after the last larval--larval molt (from the fourth to the fifth larval stadium). This sexual difference was mainly due to an increase in the number of plasmatocytes, which was more prominent in females than in males. Granular cells were dominant in early fifth larval stadium while plasmatocytes were the most abundant cells in pupae. Oenocytoids and spherule cells disappeared during the wandering stage. Lysozyme activity in the hemolymph rose to a maximum during the wandering stage, with females having lysozyme values twice as high as those for males. These changes in lysozyme activity, however, did not correlate with the increase of total hemolymph protein titer which occurred already at the beginning of the wandering stage. We postulate that changes in hemocyte titers are under direct hormonal control, which has to be proven in future experiments.

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Homeostatic and developmental control of cell size and shape in an insect epithelium, the epidermis of Manduca sexta

Bultmann

Goodman

1990

J. Exp. Zool.

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In contrast to previously described transformations of insect epidermal cells, morphological changes in the larval epidermis of Manduca sexta involve large changes in cell volume: a threefold increase at the beginning and a twofold decrease at the end of the last feeding phase. The volume changes are determined, in part, or entirely, by changes in cell height (cell elongation and cell shortening). Initial cell elongation occurs in a region-specific manner, whereas subsequent cell shortening affects all of the epidermis equally. As shown by ligation experiments and hormone treatments in tissue culture, larval changes in cell height, unlike cell elongation and differentiation in prepupae, are not regulated by developmental hormones (juvenile hormones, ecdysteroids). Instead, the maintenance of a normal columnar epithelium in fifth instars depends on continuous growth. Lack of food, especially protein, results in reversible cell shortening at any time during the feeding phase. Intake of water does not mitigate this cellular response; cell shortening is also insensitive to ouabain but inhibited by cold treatments. We propose that during larval growth epidermal cell height is under specific homeostatic control, independent of mechanisms regulating cell width, ploidy levels, or mitotic activity.

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Gain and loss of fluid in metamorphosing larvae of Manduca sexta

Cited by 6 publications

References 18 publications

Protein synthesis, DNA degradation, and morphological changes during programmed cell death in labial glands ofManduca sexta

Protein synthesis, DNA degradation, and morphological changes during programmed cell death in labial glands ofManduca sexta

Correlation of hemocyte counts with different developmental parameters during the last larval instar of the tobacco hornworm, Manduca sexta

Homeostatic and developmental control of cell size and shape in an insect epithelium, the epidermis of Manduca sexta

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