Cell Interactions in the Differentiation of a Melanotic Tumor in Drosophila

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72644/1/j.1432-0436.1979.tb01002.x.pd

Morphogenic Effects of Halogenated Thymidine Analogues on Drosophila

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74738/1/j.1432-0436.1975.tb00853.x.pd

Topology of the caudal fat body of the tumorw mutant of Drosophila melanogaster

Hereditary melanotic tumors in the tumorw strain of Drosophila melanogaster are known to involve encapsulation of the caudal fat body by the larval hemocytes. The encapsulated masses are subsequently melanized. The present study shows that the chain of events preceding encapsulation includes disintegration of the basement membrane of the caudal fat body and the appearance of particulate materials between and around the dissociating fat cells.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22314/1/0000759.pd

Distribution of bromouracil in the pyrimidine oligonucleotides of drosophila DNA

DNA was isolated from Drosophila melanogaster larvae fed radioactive thymidine (TdR), bromodeoxyuridine (BUdR), or one of these nucleosides together with 5-fluorouracil (FU) under identical conditions. The four DNA samples designated T-DNA, B-DNA, T(F)-DNA, and B(F)-DNA respectively were hydrolyzed with formic acid-diphenylamine, and the pyrimidine oligonucleotides of various chain lengths (isostichs) were fractionated by DEAF-cellulose chromatography. The distributions of the labeled thymine and bromouracil (BU) residues among the pyrimidine isostichs were determined, and compared for the four DNAs. These comparisons indicated the following: 1. (1) Similarity of T-DNA and T(F)-DNA with respect to labeled thymine distribution among the pyrimidine isostichs (using the mononucleotide to pentanucleotide tracts for statistical comparisons) showed that TdR entering DNA synthesis via the salvage pathway has the same distribution whether the synthetic pathway is operating normally or is inhibited by FU treatment.2. (2) Quantitative comparison of the distribution of BU among the isostichs of B-DNA. and B(F)-DNA with the distribution of labeled thymine in T-DNA showed significant differences, indicating that the organism does not accept BUdR indiscriminately at all thymine sites for DNA synthesis.3. (3) Comparison of the distribution of BU in B-DNA and B(F)-DNA showed that isostichs 1 and 3 differ significantly. The elution profiles of the isostichs also differed qualitatively between these DNAs. This analysis confirms differential incorporation of BUdR into Drosophila DNA in the presence of a thymidylate inhibitor.The observations on BUdR incorporation in Drosophila DNA have been discussed with relation to the high frequency of somatic cell mutations induced in imaginal disc cells by treatment with the analog in the presence of inhibitors of thymidylate synthetase.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22176/1/0000607.pd

Microtubule inhibitors block the morphological changes induced in Drosophila blood cells by a parasitoid wasp factor

The shape change of Drosophila melanogaster blood cells (lamellocytes) from discoidal to bipolar that is caused by a factor from the female parasitoid Leptopilina heterotoma is blocked by the tubulin inhibitors vinblastine and vincristine in vitro. The actin inhibitor, cytochalasin B, causes arborization of Drosophila lamellocytes and acts synergistically with the wasp factor to alter lamellocyte morphology. Lamellocyte arborization induced by cytochalasin B is blocked by simultaneous treatment with vinblastine. These observations indicate that the changes in lamellocyte shape induced by both the wasp factor and cytochalasin B require microtubule assembly.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42825/1/18_2005_Article_BF01951775.pd

Properties of the larval hemocytes of Drosophila melanogaster

Contrary to Srdić and Gloor's report, we find crystal cells (cc) in the lymph glands of D. melanogaster larvae; the size and number of inclusions in the cc cannot be used to distinguish the 2 sibling species, D. melanogaster and D. simulans ; cc in the hemocoel are not phagocytic cells; the surface properties of the lamellocytes are consistent with their derivation from plasmatocytes and not cc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42706/1/18_2005_Article_BF01976142.pd

Morphogenic effects of halogenated thymidine analogs on Drosophila III. 5-Iododeoxyuridine

Die Häufigkeit der durch 5-Iododeoxyuridin (IUdR) bei Drosophila induzierten Abnormalitäten kann durch gleichzeitige Fütterung der Larven mit 5-Fluorouracil (FU) erhöht werden. Die Menge des in die Drosophila -DNS inkorporierten IUdR ist bei Anwesenheit von FU höher; die Verteilung dieser IUdR-DNS im CsCl-Dichtegradienten ist verschieden von der in Abwesenheit von FU synthetisierten DNS.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42534/1/18_2005_Article_BF01928722.pd

Effects of lamellolysin from a parasitoid wasp on Drosophila blood cells in vitro

Female parasitoid Leptopilina heterotoma inject a factor, lamellolysin, along with their eggs into the host hemocoel to destroy selectively host hemocytes that encapsulate foreign objects. In parasitized Drosophila melanogaster larvae, these hemocytes (lamellocytes) change from discoidal cells to bipolar cells that no longer adhere to each other to form capsules. To study the effects of lamellolysin on Drosophila lamellocytes in vitro, a giant strain of D. melanogaster was constructed to yield hemolymph with an abundance of lamellocytes. The effect of lamellolysin on the adhesivity of lamellocytes in vitro was demonstrated when the cells were gently rotated in the culture medium. Under these conditions, the bipolar shape of the affected lamellocytes resembled that of lamellocytes in parasitized hosts. When lamellocytes were exposed to lamellolysin in stationary culture medium, the elongation of the bipolar cells continued until they became threadlike. Lamellocytes fragmented in both stationary and rotating culture medium in the presence of lamellolysin, although loss of cellular material was more pronounced in the latter. This study demonstrates that lamellolysin acts directly and destructively on lamellocytes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38096/1/1402570214_ftp.pd

Regulation of synthesis of larval serum proteins after transplantation of larval fat body into adult Drosophila melanogaster

The larval serum proteins, LSP1 and LSP2, of Drosophila melanogaster are synthesized by the fat body during the third instar. We examined the potential for LSP synthesis by fat body implants in adult flies. Fat body from third instar donors will continue to synthesize LSPs in both males and females. Implants from late second instar larvae will start synthesizing LSP1 and LSP2 in females but only LSP1 in males, suggesting that regulation of these proteins is not the same and that the physiological milieu in the two sexes differs. The newly synthesized LSPs are secreted into the hemolymph for approximately 48 hr when secretion stops but synthesis continues. This sequence follows the pattern for LSP secretion in situ. Fat body from mid second instar larvae is variable in its ability to synthesize LSPs. LSPs are not detected in implants from first instar larvae despite there being a high level of protein synthesis in the implant and considerable growth of the fat body cells. We conclude that there is a critical stage of differentiation during the latter half of the second instar when the fat body becomes independent of the larval milieu and can synthesize LSPs in the adult.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26107/1/0000183.pd

Leptopilina heterotoma and L. boulardi: Strategies to avoid cellular defense responses of Drosophila melanogaster

Eggs of three strains of the cynipid parasitoid Leptopilina heterotoma and a Tunisian strain (G317) of L. boulardi are not encapsulated by hemocytes of Drosophila melanogaster hosts, but the eggs of a Congolese strain (L104) of L. boulardi are encapsulated. To determine the reason for the difference in host response against the parasitoid eggs, lamellocytes (hemocytes that encapsulate foreign objects and form capsules around endogenous tissues in melanotic tumor mutants) were examined in host larvae parasitized by the five Leptopilina strains. Parasitization by the three L. heterotoma strains affected the morphology of host lamellocytes and suppressed endogenous melanotic capsule formation in melanotic tumor hosts. L104 did not alter the morphology of host lamellocytes nor block tumor formation in melanotic tumor mutant hosts. The morphology of some lamellocytes was affected by G317 parasitization but host lamellocytes were still capable of forming melanotic tumors and encapsulating dead supernumerary parasitoid larvae. Therefore, the eggs of strains affecting lamellocyte morphology are protected from encapsulation by the host's blood cells. L. heterotoma eggs float freely in the host hemocoel but L. boulardi eggs are attached to host tissue surfaces. Lamellocytes cannot infiltrate the attachment site so the capsule around the L104 egg remains incomplete. The wasp larva uses this gap in the capsule as an escape hatch for emergence.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28608/1/0000417.pd