James Timbilla's research while affiliated with CUNY Graduate Center and other places

Publications (9)

Article
Since the 1970s, the pestilence of dry season populations of the polyphagous grasshopper Zonocerus variegatus (Orthoptera: Pyrgomorphidae) has impacted negatively on agriculture and forestry in Sub-Saharan Africa. Current chemoecological knowledge indicates that outbreaks of Z. variegatus may be due to sequestration of protective Pyrrolizidine Alka...
Data
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Amino acid alignment of flavin-dependent monooxygenases of various insect species. Only the central part of the alignment that was used for the estimation of the phylogenies is shown, spanning the region from amino acid position 5 to 402 with respect to ZvPNO. The sequence motifs for binding of FAD and NADPH and the FMO-identifying sequence are box...
Article
Full-text available
Several insect lineages have developed diverse strategies to sequester toxic pyrrolizidine alkaloids from food-plants for their own defense. Here, we show that in two highly divergent insect taxa, the hemimetabolous grasshoppers and the holometabolous butterflies, an almost identical strategy evolved independently for safe accumulation of pyrrolizi...
Data
Full-text available
PNO activity in three buffer systems with pH variation. Enzyme activities have been determined with senecionine as substrate at 37°C. (PDF)
Data
Sequences of primers used for the identification and cloning of cDNAs of flavin-dependent monooxygenases of Zonocerus variegatus. Recognition sites of restriction endonucleases used for cloning are underlined. (DOC)
Article
The increasing importance of dry season populations of the African polyphagous grasshopper, Z. variegatus as a pest in agriculture and forestry has been attributed to the sequestration of pyrrolizidine alkaloids (PAs) from the flowers of the exotic noxious weed Chromolaena odorata for defense against natural enemies and protection of its diapausing...
Article
Cabbage, Brassica oleraceae var. capitata is an important vegetable grown and consumed in Ghana. Apart from infestations of the lepidopterous Plutella xylostella and Hellula undalis resulting from continuous cultivation, a new pest Zonocerus variegatus has been reported to causing damage to the crop. The efficacy of a novel pyrrolizidine alkaloid (...
Article
Full-text available
Current research has shown that derivatives of pyrrolizidine alkaloids (PA) from the dry chopped roots of Chromolaena odorata (Asteraceae) are effective lures for Z. variegatus. Bioassays on the effect of a developed PA-based attracticides on 4th instar nymphs of Z. variegatus were conducted in the laboratory with a completely randomized design. Th...

Citations

... Meanwhile in Ghana/Africa, however, few research on honeys was only focused on economic benefits and proximate analysis (Ankrah 1998) and physicochemical properties (Amri and Ladjama 2013), rather than their potential toxicological effects due to PAs. Moreover, a recent study in Ghana revealed a frequent occurrence of PA-containing plants such as Chromolaena odorata and Ageratum conyzoides (Asteraceae), Heliotropium indicum (Boraginaceae), and Crotalaria retusa (Fabaceae) (Timbilla and Lawson 2014), whereas A. conyzoides and C. retusa were found in all six agro-ecological zones of the country (Figure 1). C. odorata and H. indicum were restricted to four zones, i.e. the Savannah-forest transition, Deciduous rain forest, Evergreen rain forest and Coastal savannah zones, thus raising concerns of a likelihood of significant amounts of toxic PAs from these plants in Ghanaian honeys. ...
... Une étude a montré l'intérêt du N-oxyde d'indicine, un AP, dans le traitement des patients atteint d'un cancer avancé (Ohnuma et al., 1982). Les AP peuvent aussi être exploités en agriculture dans la lutte contre les nématodes des racines (Thoden et al., 2007) et les sauterelles (Timbilla et al., 2008). ...
... Because sequestration of PAs probably evolved early in the Arctiinae (formerly Arctiidae, now included in the Erebidae), it seems likely that duplication of FMO1 and the evolution of enzymatic PA specificity are linked to the evolution of sequestration in the arctiines. Remarkably, a convergent scenario involving gene duplication leading to a PA N-oxygenating FMO was found in the pyrgomorphid grasshopper Zonocerus variegatus (105). Nevertheless, there are additional mechanisms in PA-sequestering leaf beetles (Oreina cacaliae) that can prevent the activation of alkaloid N-oxides in the gut and efficiently absorb them into the body (38). ...
... The northeast region of Nigeria is the second largest livestock producer in Nigeria (Majiayagbe and Lamorde, 1997), but very little has been done or documented about the rich "microlivestock" population of this region and the high cost of animal protein, which is beyond the reach of the highly impoverished population has reawakened and encouraged entomophagy in this part of the country more than other parts. This renewed interest in entomophagy will also also help to reduce the pest role of Zonocerus variegtus which requires attracticides (Timbilla et al., 2007) to control in Africa and many parts of the world. ...