Juvenile hormone degradation in brain and corpora cardiaca-corpora allata complex during the last larval instar ofGalleria mellonela (Lepidoptera, Pyralidae)

1986 ◽  
Vol 42 (2) ◽  
pp. 167-169 ◽  
Author(s):  
J. R. Wiśniewski ◽  
M. Muszyńska-Pytel ◽  
M. Kochman
1992 ◽  
Vol 47 (5-6) ◽  
pp. 449-452 ◽  
Author(s):  
Elisabeth Lehmberg ◽  
Hans-J. Ferenz ◽  
Shalom W. Applebaum

Corpora allata (CA) from male Locusta migratoria were tested for their ability to synthesize juvenile hormone (JH) and to respond to stimulating brain/corpora cardiaca (CC) extracts under in vitro conditions. We found that a preincubation of the CA of both sexes at 4 °C for 24 h lowers their basal rate of synthesis and retains their responsiveness to allatotropic factors. Male CA can be stimulated by brain/CC extracts as well as female CA. JH biosynthesis stimulating factors are also present in male brain/CC extracts. Thus such extracts from male locusts can be used for the isolation of locust allatotropin. Furthermore male locust CA are appropriate for bioassaying such allatotropic factors.


2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Xiaoguang Liu ◽  
Xia Ning ◽  
Yan Zhang ◽  
Wenfeng Chen ◽  
Zhangwu Zhao ◽  
...  

The silkworm, Bombyx mori, is an important economic insect for silk production. However, many of the mature peptides relevant to its various life stages remain unknown. Using RP-HPLC, MALDI-TOF MS, and previously identified peptides from B. mori and other insects in the transcriptome database, we created peptide profiles showing a total of 6 ion masses that could be assigned to peptides in eggs, including one previously unidentified peptide. A further 49 peptides were assigned to larval brains. 17 new mature peptides were identified in isolated masses. 39 peptides were found in pupal brains with 8 unidentified peptides. 48 were found in adult brains with 12 unidentified peptides. These new unidentified peptides showed highly significant matches in all MS analysis. These matches were then searched against the National Center for Biotechnology Information (NCBI) database to provide new annotations for these mature peptides. In total, 59 mature peptides in 19 categories were found in the brains of silkworms at the larval, pupal, and adult stages. These results demonstrate that peptidomic variation across different developmental stages can be dramatic. Moreover, the corpora cardiaca-corpora allata (CC-CA) complex was examined during the fifth larval instar. A total of 41 ion masses were assigned to peptides.


1971 ◽  
Vol 26 (2) ◽  
pp. 154-157 ◽  
Author(s):  
Ch. Hintze-Podufal

The two synthetic farnesol derivatives, farnesyl methyl ether and the dihydrochloride of ethylfarnesoate were found to be morphogenetically effective in a distinguishable manner in the last larval instar of Cerura vinula L. by topical application assays. The juvenile hormone-like activity of the two substances correlates with the amount of applied substances and a critical time interval to the prepupal processes. In spite of the deficiency of some prepupal processes, it is possible, that the pupal moult occurs after a long period of delay.The time lapse of the pupal development is suggested to be dependent upon some balance of the hormones of the prothoracic glands, ecdysone, and the juvenile hormone of the corpora allata.


1974 ◽  
Vol 61 (2) ◽  
pp. 493-501 ◽  
Author(s):  
H. FREDERIK NIJHOUT ◽  
CARROLL M. WILLIAMS

During the final larval instar of the tobacco hornworm the presence of juvenile hormone (JH) inhibits the secretion of the brain's prothoracicotropic hormone (PTTH). The corpora allata cease to secrete JH when the larvae attain a weight of approximately 5 g. The JH is cleared from the haemolymph in about 24 h. This process in itself renders the brain competent to release PTTH. The actual release of PTTH occurs at the very first photo-periodic gate after the JH has disappeared from the haemolymph. A functional failure of this normal mechanism is apparently responsible for the developmental standstill of Lepidoptera which diapause as mature larvae.


2013 ◽  
Vol 104 (2) ◽  
pp. 203-212 ◽  
Author(s):  
A. Valigurová ◽  
V. Michalková ◽  
P. Koník ◽  
M.L. Dindo ◽  
M. Gelnar ◽  
...  

AbstractThe tachinid fly Exorista larvarum (L.) (Diptera: Tachinidae) is a polyphagous larval endoparasitoid that deposits its eggs on the host exoskeleton of lepidopteran and tenthredinid larvae. The attachment of larval E. larvarum and the formation of the respiratory funnel were studied during infestation in the last larval instar of the wax moth, Galleria mellonella (L.) (Lepidoptera: Pyralidae). The tachinid larvae burrow through the host integument after hatching, using their robust cephalopharyngeal skeleton, leaving a dark spot at the point of their penetration as a result of host cuticle melanization. Endoparasitoid penetration induces the host cellular defence, resulting in the formation of a haemocyte capsule consisting of multi-cellular sheaths. This enveloping capsule later undergoes melanization, which is mostly obvious towards the posterior part of the endoparasitoid. The endoparasitoid uses the host encapsulation response to build a respiratory funnel from the modified host integument, leading to the host surface. The encapsulated larva remains attached to the respiratory funnel via an anal hook and cuticular spines until fully developed. Additional immunohistochemical analyses were used to study host–parasitoid interactions. Indirect immunofluorescence showed no labelling of potential tachinid antigens and confirmed no effect on the surrounding host tissues. A simulated parasitization with coated polybead microspheres revealed the mortal impact of tachinid antigens to the host. Hosts injected with antigen-coated polybeads died as a consequence of an acute and extensive immunological response to the tachinid antigens and not due to the trauma caused by foreign objects inside their body.


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