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  • 1
    ISSN: 1573-1561
    Keywords: Insect antifeedant ; Spodoptera littoralis (Boisd.) ; Lepidoptera ; Noctuidae ; Clerodane diterpenoids ; Ajuga plants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Antifeedant activities of nine clerodane diterpenoids, isolated in this laboratory from different species ofAjuga plants, have been studied against larvae of Egyptian cotton leafwormSpodoptera littoralis (Boisd.) (Lepidoptera) by application of the leaf disk method. Evaluation of activity was carried out by calculating, at different time intervals, the feeding ratio (FR) from the relationship between the consumed areas of treated disks (CTD) and control disks (CCD); for comparison purposes a FR50 defined as the FR at a CCD of 50% was established. Some compounds exhibited activity at a 0.01 μg/cm2 dose (0.3 ppm). Structure-activity relationships are discussed
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-1561
    Keywords: Sex attractant ; sex pheromone ; processionary moth ; Thaumetopoea pityocampa ; Lepidoptera ; Notodontidae ; (Z)-13-hexadecen-11-ynyl acetate ; field test
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Synthetic (Z)-13-hexadecen-11-ynyl acetate has been shown to be highly active in catchingThaumetopoea pityocampa (Denis and Schiff.) males in field trials carried out in different parts of Spain. A variety of formulations containing antioxidants or solid paraffin were tested. Formulations containing 3 and 10% ofE isomer showed a decrease of activity compared with those prepared with pureZ isomer. Dodecyl acetate, also found in the virgin female gland, did not show any synergistic effect when tested in a 9∶1 mixture with the synthetic pheromone. The product exhibited a remarkable persistence of activity under the field conditions even in the absence of stabilizer.
    Type of Medium: Electronic Resource
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  • 3
    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
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  • 4
    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.
    Type of Medium: Electronic Resource
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