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Ultrastructural changes induced by precocene II and 3,4-dihydroprecocene II in the corpora allata of Blattella germanica (1989)

Piulachs, Maria-Dolors ; Cassier, Pierre ; Bellés, Xavier

Springer

Cell & tissue research 258 (1989), S. 91-99

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ISSN: 1432-0878

Keywords: Corpora allata ; Ultrastructure ; Precocenes ; Juvenile hormone ; Blattella germanica (Insecta)

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine

Notes: Summary Ultrastructural studies on corpora allata (CA) from different stages during the first gonadotropic cycle of the cockroach Blattella germanica have shown well defined changes which have a correspondence with oocyte length, CA volume and juvenile hormone (JH) biosynthesis. The most significant variations concern the mitochondria and the endoplasmic reticulum. Topically applied precocene II (P II) at a dose of 200 ⧎g induced a transient arrest of CA function, although cytotoxic effects were occasionally observed. When CA were maintained in vitro with 10-3 M of P II, a relationship between the time of treatment (3, 6 or 9 h) and the intensity of the effects was apparent. The 9-h treatment led to an irreversible inhibition of JH production which parallels the severe damages observed in the CA (membrane lysis, nuclear pyknosis, vacuolization). Equivalent studies performed with the chroman derivative 3,4-dihydroprecocene II (DHP II) showed that it is less active than P II. Only treatments as severe as 12 h of incubation with a 10-3 M concentration elicited cytotoxic effects which could be due to radical species involved in the in situ oxidative bioactivation of DHP II. Thus, this compound could be regarded as a new type of pro-allatocidin.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00223148

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Stimulating action of methyl 12, 12, 12-trifluorofarnesoate on in vitro juvenile hormone III biosynthesis in blattella germanica (1989)

Bellés, Xavier ; Camps, Francisco ; Casas, Josefina ; [et al.]

New York, NY [u.a.] : Wiley-Blackwell

Archives of Insect Biochemistry and Physiology 11 (1989), S. 257-270

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ISSN: 0739-4462

Keywords: German cockroach ; corpora allata ; farnesoic acid ; 12, 12, 12-trifluorofarnesoic acid ; 12, 12, 12-trifluorofarnesol ; Chemistry ; Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology

Notes: Methyl 12, 12, 12-trifluorofarnesoate (MTFF) at a dose of 10 μM, stimulated in vitro juvenile hormone (JH) release in corpora allata (CA) from 6-day-old, freshly ecdysed, and 8-day-old (period of ootheca transport) adult virgin females of Blattella germanica. In addition, MTFF also induced intraglandular accumulation of JH and MF in treated CA. Trifluorofarnesoic acid (TFFA) and trifluorofarnesol (TFF) exhibited the same properties, although to a lesser extent than MTFF. The detection of MTFF in TFFA-treated CA suggested that TFFA and TFF were biotransformed into MTFF by the CA enzymatic system and that this ester might be responsible for the activity observed. Equivalent experiments carried out with farnesoic acid (FA) resulted in a more significant stimulation of JH production. This is not surprising, because exogenous FA is readily epoxidized at C10-C11 double bond and methylated to afford JH. Conversely, analytical data have shown that the C6-C7 double bond of MTFF is epoxidized by the CA enzymatic system, whereas that at C10-C11 remains practically unaltered.

Additional Material: 3 Ill.