The Experts below are selected from a list of 366 Experts worldwide ranked by ideXlab platform
Seiji Tanaka - One of the best experts on this subject based on the ideXlab platform.
-
wing dimorphism in the migratory locust locusta migratoria differentiation of wing morph and phase polyphenism
Entomological Science, 2013Co-Authors: Yudai Nishide, Seiji TanakaAbstract:A short-winged morph was recently discovered in the migratory locust, Locusta migratoria. It is different from the normal, long-winged morph not only in forewing length but also in hind femur length, displaying a dimorphism. To understand the significance of this dimorphism, other morphological characters were compared between the two morphs, and the time of differentiation of wing-pad length was investigated. Wing weights were heavier in the long-winged morph than in the short-winged morph. This result showed that the short-winged morph is not formed by a failure of wing expansion. No obvious morph-specific differences were observed in wing venation, but wing allometry studies indicated that the distal areas of the fore- and hindwings were disproportionally reduced in the short-winged morph compared to the long-winged morph. The morphological differentiation of the wing pad between the two morphs was observed at the penultimate nymphal stage. The flight muscle was well developed in the two morphs, and no sign of flight muscle Histolysis was detected in either morph after adult emergence. An analysis of adult body dimensions suggested that the density-dependent phase shifts known for the long-winged morph of this locust were also exhibited by the short-winged morph, demonstrating that these shifts are not specific to the migratory long-winged morph.
-
effects of suppressed oviposition activity and flight muscle Histolysis on food consumption and ovarian development in a wing dimorphic cricket an explanation for sporadic conclusions related to physiological trade offs
Journal of Insect Physiology, 2001Co-Authors: Seiji TanakaAbstract:The effects of deprivation of oviposition substrate on food consumption and egg production were compared between the long-winged (LW) and the short-winged (SW) morph of a cricket, Modicogryllus confirmatus, to determine how suppressed oviposition activity would influence these traits in each wing morph. Food consumption was greatly suppressed in females deprived of oviposition substrate (-OS) compared to those given access to it (+OS) during the 2-week feeding trial in the SW morph but not in the LW morph. Some LW females shed their hindwings and histolyzed the flight muscles. Such de-alated LW (DLW) morphs tended to consume more food than intact LW (ILW) morphs. In all morphs, ovarian weight was heavier under -OS conditions than under +OS conditions during the second week of adulthood, although the differences were greater in SW morphs than in ILW morphs. In DLW morphs in which flight muscle Histolysis was induced by artificial de-alation at adult emergence, the temporal changes in ovarian weight were similar to those of SW morphs.In SW morphs, food consumption was also significantly reduced when ovipositing females were deprived of oviposition substrate for 2 days compared to those allowed to oviposit continuously, but food consumption was not reduced in ILW or DLW morphs. SW females from which one ovary was extirpated at adult emergence, SW (-o), also showed a significant difference in food consumption when treated as above, indicating that food consumption was not determined simply by the number of ovarian eggs. The crop content was positively correlated to food consumption and smaller under -OS conditions than under +OS conditions. The 2-day deprivation of oviposition substrate caused no significant difference in the total number of deposited and ovarian eggs in any group, but the ovarian mass of developing oocytes tended to be smaller under -OS than under +OS conditions, particularly in SW morphs.These results indicate the possibility that some inconsistent results and conclusions discussed in recent studies, concerning the physiological trade-offs between flight capability and reproduction, were caused by the suppressed oviposition activity and failure to recognize the occurrence of flight muscle growth and Histolysis in the test crickets.
-
Endocrine control of ovarian development and flight muscle Histolysis in a wing dimorphic cricket, Modicogryllus confirmatus
Journal of Insect Physiology, 1994Co-Authors: Seiji TanakaAbstract:Abstract The role of juvenile hormone, juvenile hormone esterase and 20-hydroxyecdysone in regulating ovarian development and flight muscle Histolysis was examined in a wing dimorphic cricket, Modicogryllus confirmatus. Topical application of a juvenile hormone analog, methoprene, increased egg production and incidence of flight muscle Histolysis in both intact and neck-ligated long-winged adults. Flight muscle Histolysis appeared to proceed without interruption once it was initiated. Exogenous juvenile hormone III stimulated flight muscle Histolysis but failed to elicit any significant effect on ovarian development. It is likely that flight muscle Histolysis is an all-or-none response triggered by a pulse of juvenile hormone while ovarian development requires a continuous exposure to the hormone and shows a graded response. Injection of 20-hydroxyecdysone elicited no influence on ovarian development or flight muscle Histolysis. The juvenile hormone esterase profiles provided no direct evidence to explain the morph-specific differences in egg production and the occurrence of flight muscle Histolysis. However, a significant inverse relationship between juvenile hormone esterase activity and corpus allatum size may suggest that this enzyme plays a role in regulating the juvenile hormone titer in each wingmorph.
-
de alation and its influences on egg production and flight muscle Histolysis in a cricket velarifictorus parvus that undergoes inter reproductive migration
Journal of Insect Physiology, 1991Co-Authors: Seiji TanakaAbstract:Abstract The effects of de-alation on egg production and flight muscle development were studied in the tambo cricket, Velarifictorus parvus Chopard. Artificial de-alation at adult emergence did not influence the pre-oviposition period, fecundity and longevity, but modified the oviposition schedule. Artificially de-alated females showed intensive egg production during the early stage of adult life while unoperated females attained peak ovipositing activity much later. Dissection indicated that artificial de-alation stimulated rapid egg production in the ovaries as well as flight muscle Histolysis. When no food was given, intact females developed the flight muscles but produced no eggs during the first 5 days after adult emergence. Under the same conditions, artificially de-alated females broke down the flight muscles and produced 23 eggs on average. These results indicate that intact crickets invest the energy reserves for the flight muscles rather than for reproduction, whereas de-alated females use it for reproduction. In fed crickets, natural de-alation occurred mostly after maximal ovipositing activity was attained, suggesting that natural de-alation was not the direct cause for initiation of rapid egg production. This trait, as well as the relatively short pre-oviposition period, seems related to the type of migration this cricket shows, i.e. inter-reproductive rather than pre-reproductive. The cause of natural de-alation is unknown, but flight muscle Histolysis and de-alation could be induced when crickets experienced a serious damage or loss of the flight ability.
Tatsuya Nishimoto - One of the best experts on this subject based on the ideXlab platform.
-
feeding conditions modify the photoperiodically induced dispersal of the water strider aquarius paludum heteroptera gerridae
European Journal of Endocrinology, 2007Co-Authors: Tetsuo Harada, Tatsuya NishimotoAbstract:Overwintering adults of the water strider, Aquarius paludum were collected from the field in fall and kept under short days (12L : 12D) at 20°C for a week. A control group was then kept at 12L : 12D and fed daily, and three experimental groups were transferred to 15.5L : 8.5D and fed at different frequencies: daily or every 2nd or 3rd day. Temperature was kept at 20°C. Flight behaviour of the adults in the four groups was recorded every 10 days up to the end of the 5th week when the adults were dissected. State of the flight muscles and reproductive organs (ovaries and testes) was recorded. Flight ability of the adults fed every 3rd day (Group 3) was higher than that of those fed daily (Group 1). Seventy percent of the females that were fed every 3rd day (Group 3) remained in diapause for 5 weeks, in spite of the reproduction promoting long-days, while none of the females fed every day remained in diapause (Group 1). Flight muscle Histolysis, promoted by long-days, was inhibited by poor feeding conditions. Thus, they can migrate and seek more suitable water bodies rich in food. The modifying effect of the availability of food on the trade-off between reproduction and flight is recorded here for the first time for a carnivorous insect.
Tetsuo Harada - One of the best experts on this subject based on the ideXlab platform.
-
feeding conditions modify the photoperiodically induced dispersal of the water strider aquarius paludum heteroptera gerridae
European Journal of Endocrinology, 2007Co-Authors: Tetsuo Harada, Tatsuya NishimotoAbstract:Overwintering adults of the water strider, Aquarius paludum were collected from the field in fall and kept under short days (12L : 12D) at 20°C for a week. A control group was then kept at 12L : 12D and fed daily, and three experimental groups were transferred to 15.5L : 8.5D and fed at different frequencies: daily or every 2nd or 3rd day. Temperature was kept at 20°C. Flight behaviour of the adults in the four groups was recorded every 10 days up to the end of the 5th week when the adults were dissected. State of the flight muscles and reproductive organs (ovaries and testes) was recorded. Flight ability of the adults fed every 3rd day (Group 3) was higher than that of those fed daily (Group 1). Seventy percent of the females that were fed every 3rd day (Group 3) remained in diapause for 5 weeks, in spite of the reproduction promoting long-days, while none of the females fed every day remained in diapause (Group 1). Flight muscle Histolysis, promoted by long-days, was inhibited by poor feeding conditions. Thus, they can migrate and seek more suitable water bodies rich in food. The modifying effect of the availability of food on the trade-off between reproduction and flight is recorded here for the first time for a carnivorous insect.
-
effects of low temperature on the condition of flight muscles and flight propensity in a water strider aquarius paludum heteroptera gerridae
European Journal of Entomology, 2003Co-Authors: Tetsuo Harada, Shizuna Inoue, Masao WatanabeAbstract:Effects of chilling on dispersal characteristics of adults of the water strider, Aquarius paludum were studied in the laboratory. The condition of flight muscles was monitored during overwintering under natural conditions in Kochi (33°N), Japan. For diapause adults kept under 12h light-12h dark (12L : 12D), chilling at 7°C for 48h from the 70th day after emergence caused lower Supercooling Point (SCP) and promoted higher flight propensity than among gerrids not exposed to chilling. For reproductive adults kept under 15.5L : 8.5D, 91.3% of 34 adults retained well-developed flight muscles 1 week after the chilling (49 days after emergence), whereas 67.6% of 49 adults which had not been exposed to 7°C histolysed their flight muscles. According to diapause development, part of the adults which had well developed flight muscles histolysed them during December to February. Chilling in fall might trigger dispersal to overwintering sites by diapause adults and, that in spring could inhibit Histolysis of flight muscles by overwintered reproductive adults.
Yadav Kuleesha - One of the best experts on this subject based on the ideXlab platform.
-
live imaging of muscle Histolysis in drosophila metamorphosis
BMC Developmental Biology, 2016Co-Authors: Yadav Kuleesha, Wee Choo Puah, Martin WasserAbstract:Background The contribution of programmed cell death (PCD) to muscle wasting disorders remains a matter of debate. Drosophila melanogaster metamorphosis offers the opportunity to study muscle cell death in the context of development. Using live cell imaging of the abdomen, two groups of larval muscles can be observed, doomed muscles that undergo Histolysis and persistent muscles that are remodelled and survive into adulthood.
-
live imaging of muscle Histolysis in drosophila metamorphosis
bioRxiv, 2016Co-Authors: Yadav Kuleesha, Wee Choo Puah, Martin WasserAbstract:Background: The contribution of programmed cell death (PCD) to muscle wasting disorders remains a matter of debate. Drosophila melanogaster metamorphosis offers the opportunity to study muscle cell death in the context of development. Using live cell imaging of the abdomen, two groups of larval muscles can be observed, doomed muscles that undergo Histolysis and persistent muscles that are remodelled and survive into adulthood. Method: To identify and characterize genes that control the decision between survival and cell death of muscles, we developed a method comprising in vivo imaging, targeted gene perturbation and time-lapse image analysis. Our approach enabled us to study the cytological and temporal aspects of abnormal cell death phenotypes. Results: In a previous genetic screen for genes controlling muscle size and cell death in metamorphosis, we identified gene perturbations that induced cell death of persistent or inhibit Histolysis of doomed larval muscles. RNA interference (RNAi) of the genes encoding the helicase Rm62 and the lysosomal Cathepsin-L homolog Cysteine proteinase 1 (Cp1) caused premature cell death of persistent muscle in early and mid-pupation, respectively. Silencing of the transcriptional co-repressor Atrophin inhibited Histolysis of doomed muscles. Overexpression of dominant-negative Target of Rapamycin (TOR) delayed the Histolysis of a subset of doomed and induced ablation of all persistent muscles. RNAi of AMPKα, which encodes a subunit of the AMPK protein complex that senses AMP and promotes ATP formation, led to loss of attachment and a spherical morphology. None of the perturbations affected the survival of newly formed adult muscles, suggesting that the method is useful to find genes that are crucial for the survival of metabolically challenged muscles, like those undergoing atrophy. The ablation of persistent muscles did not affect eclosion of adult flies. Conclusions: Live imaging is a versatile approach to uncover gene functions that are required for the survival of muscle undergoing remodelling, yet are dispensable for other adult muscles. Our approach promises to identify molecular mechanisms that can explain the resilience of muscles to PCD.
-
Additional file 2: Figure S1. of Live imaging of muscle Histolysis in Drosophila metamorphosis
2016Co-Authors: Yadav Kuleesha, Wee Choo Puah, Martin WasserAbstract:Expression of the 24B-GAL4 driver in metamorphosis. In (A) prepupae and (B) pupae, the mesodermal 24B-Gal4 driver is expressed in multi-nucleated muscles (outlined in black) and more apically located mono-nucleated cells (white arrow). Cells were labelled with the mitochondrial marker UAS-Mito-GFP (green) and UAS-histone-mKO (magenta). (B) During pupation, mono-nucleated cells (white arrow) undergo PCD and show nuclear fragmentation, while nuclei (black arrow) in muscles undergoing Histolysis, like the DIOM2s (outlined in black), condense without showing fragmentation (see Fig. 2). (PDF 218 kb
Lawrence I Gilbert - One of the best experts on this subject based on the ideXlab platform.
-
a reappraisal of the hormonal regulation of larval fat body Histolysis in female drosophila melanogaster
Cellular and Molecular Life Sciences, 1993Co-Authors: D S Richard, A E Arnim, Lawrence I GilbertAbstract:The Histolysis of larval fat body cells in adult femaleDrosophila melanogaster was examined in wild type and mutant animals. The fat body cells of wild type (Canton-S),apterous56f homozygotes,apterous78jts homozygotes and heterozygotes,apterous4/+, ecdysoneless1 homozygotes and heterozygotes all underwent Histolysis normally during the 72 h following adult eclosion. Only in the case ofap4/ap4 adults did the cells fail to histolyze normally. The fat body cells of both diapausing and non-diapausing wild type females underwent Histolysis at the same rate. Attempts to demonstrate Histolysis in vitro were unsuccessful, even in the presence of juvenile hormones (JHs), larval ring glands, or adult ovaries. In all strains other than theap4 homozygotes, a significant proportion of larval fat body cells were dead at any time while theap4/ap4 animals, almost all cells remained viable. It is postulated that fat body cell lysis following eclosion is not a JH-mediated event, but is elicited by an as yet unidentified factor(s), possibly originating in the ovary.