Highlights d Development of a mouse model of pancreatic adenocarcinoma (PDA)-induced cachexia d Model develops progressive wasting associated with advancing pancreas pathology d Induction of cachexia in adult KPP mice models tissue loss in PDA cancer patients d Gene ontology of cachectic muscles from KPP mice resembles that of PDA patients

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Studies were conducted across the southern United States to characterize the efficacy of multiple Bacillus thuringiensis (Bt) events in a field corn, Zea mays L., hybrid for control of common lepidopteran and coleopteran pests. Cry1F protein in event TC1507 and Cry1A.105 + Cry2Ab2 proteins in event MON 89034 were evaluated against pests infesting corn on above-ground plant tissue including foliage, stalks, and ears. Cry34Ab1/Cry35Ab1 proteins in event DAS-59122-7 and Cry3Bb1 in event MON 88017 were evaluated against the larvae of Mexican corn rootworm, Diabrotica virgifera zeae Krysan and Smith, which occur below-ground. Field corn hybrids containing Cry1F, Cry1A.105 + Cry2Ab2, Cry34Ab1/Cry35Ab1, and Cry3Bb1 insecticidal proteins (SmartStax) consistently demonstrated reductions in plant injury and/or reduced larval survivorship as compared with a non-Bt field corn hybrid. Efficacy provided by a field corn hybrid with multiple Bt proteins was statistically equal to or significantly better than corn hybrids containing a single event active against target pests. Single event field corn hybrids provided very high levels of control of southwestern corn borer, Diatraea grandiosella (Dyar), lesser cornstalk borer, Elasmopalpus lignosellus (Zeller), and fall armyworm, Spodoptera frugiperda (J.E. Smith), and were not significantly different than field corn hybrids with multiple events. Significant increases in efficacy were observed for a field corn hybrid with multiple Bt events for sugarcane borer, Diatraea saccharalis (F.), beet armyworm, Spodoptera exigua (Hübner), corn earworm, Helicoverpa zea (Boddie), and Mexican corn rootworm. Utilization of field corn hybrids containing multiple Bt events provides a means for managing insect resistance to Bt proteins and reduces non-Bt corn refuge requirements.

The amount of Cry1Ac δ-endotoxin in transgenic Bacillus thuringiensis Berliner (Bt) or Bollgard cotton varies among commercial cultivars. These differences in expression have been correlated with survival levels in Lepidoptera, indicating that all Bollgard cultivars do not provide the same level of control. The objective of this study was to determine if differences in overall expression among commercial cultivars of Bollgard cotton were under simple genetic control. These findings could influence the way breeders select cultivars by evaluating for efficacy in insect control in addition to agronomic traits. Two sets of crosses were made in the greenhouse with cultivars that express the endotoxin at high and low levels. The parents and F 1 and F 2 generations were planted in the field. The amount of Cry1Ac was quantified using a commercial ELISA kit. Variances within the two F 2 breeding populations were highly significant because of genetic segregation for Cry1Ac expression. Using the modified Castle-Wright formula, the estimation of the number of contributing genes in both breeding populations was small. These data show that genetic background has a major effect on Cry1Ac expression. Because backcrossing is the primary method used by commercial cotton breeders, the selection and use of donor and/or recurrent parents that will result in a high level of Cry1Ac expression is crucial.

Efficacy of two insect-resistant corn hybrids expressing the Cry1 F insecticidal crystal protein of Bacillus thuringiensis var. aizawai Berliner (transformation event TC1507) was evaluated against fall armyworm, Spodoptera frugiperda (J.E. Smith), in three southern U.S. locations. Larval susceptibility was evaluated on CrylF and nonBt field corn, Zea mays L., plants (V3–V12 and R1–R2 stages) in field plots and laboratory studies. Leaf-feeding injury was significantly less and plant height was significantly greater for hybrids containing Cry1 F as compared with nonBt corn hybrids when exposed to natural or artificial fall armyworm infestations. In addition, larval mortality was significantly greater on CrylF corn hybrids compared with that on nonBt hybrids. These results demonstrate that corn hybrids containing CrylF represent an effective plant incorporated insecticidal protein management option for fall armyworm. In environments where fall armyworm may exceed damage thresholds and have to be carefully managed with foliar sprays, utilization of CrylF corn hybrids will allow growers flexibility in planting and an efficient means for managing infestations.

No abstract

Cotton plants were infested with brown stink bug, Euschistus servus (Say), to define cotton boll age classes (based on heat unit accumulation beyond anthesis) that are most frequently injured during each of the initial 5 wk of flowering. Bolls from each week were grouped into discrete age classes and evaluated for the presence of stink bug injury. Brown stink bug injured significantly more bolls of age class B (approximately 165-336 heat units), age class C (approximately 330-504 heat units), and age class D (approximately 495-672 heat units) during the initial 3 wk in both years and in week 5 in 2002 compared with other boll ages. Generally, the frequency of injured bolls was lowest in age class A (< or = 168 heat units) during these periods. The preference by brown stink bug for boll age classes B, C, and D within a week was similar when ages were combined across all 5 wk. Based on these data, bolls that have accumulated 165.2 through 672 heat units beyond anthesis (approximately 7-27-d-old) are more frequently injured by brown stink bug when a range of boll ages are available. The boll ages in our studies corresponded to a boll diameter of 1.161-3.586 cm with a mid-range of 2.375 cm. A general protocol for initiating treatments against stink bugs is to sample bolls for evidence of injury as an indicator of presence of infestations in cotton. Sampling bolls within a defined range, which is most likely to be injured, should improve the precision of this method in detecting economic stink bug infestations in cotton.

Cotton, Cossypium hirsutum L, plants expressing Cry1Ac and Cry1F (Phytogen 440W) insecticidal crystal proteins of Bacillus thuringiensis (Bt) Berliner, were evaluated against natural populations of tobacco budworm, Heliothis virescens (F.), and bollworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), across 13 southern U.S. locations that sustained low, moderate, and high infestations. The intrinsic activity of Phytogen 440W was compared with nontreated non-Bt cotton (PSC355) and with management strategies in which supplemental insecticides targeting heliothines were applied to Phytogen 440W and to PSC355 cotton. Infestations were composed primarily of bollworm, which is the least sensitive of the heliothine complex to Cry toxins. Therefore, damage recorded in these studies was primarily due to bollworm. Greater than 75% of all test sites sustained heliothine infestations categorized as moderate to high (10.6-64.0% peak damaged bolls in nontreated PSC355). Phytogen 440W, alone or managed with supplemental insecticide applications, reduced heliothine-damaged plant terminals, squares (flower buds), flowers, and bolls equal to or better (1.0-79.0-fold) than managing a non-Bt cotton variety with foliar insecticides across all infestation environments. Rarely (frequency of < or = 11% averaged across structures), sprayed Phytogen 440W reduced damaged structures compared with nontreated Phytogen 440W. Protection against heliothine-induced plant damage was similar across the three levels of infestation for each viable management strategy, with exception to damaged squares for nontreated Phytogen 440W. In situations of moderate to high heliothine infestations, cotton plants expressing Cry1Ac and Cry1F may sustain higher levels of damage compared with that same variety in low infestations. No significant difference in yield was observed among heliothine management strategies within each infestation level, indicating cotton plants may compensate for those levels of plant damage. These findings indicate Phytogen 440W containing Cry1Ac and Cry1F provided consistent control of heliothines across a range of environments and infestation levels.