Cyclic CO(2) release in Cryptotermes cavifrons Banks, Incisitermes tabogae (Snyder) and I. minor (Hagen) (Isoptera: Kalotermitidae).

CO(2) release patterns of three drywood termite species were investigated using flow-through respirometry techniques. Eight hours of real-time CO(2) release data were recorded for pseudergates of Cryptotermes cavifrons Banks, Incisitermes minor (Hagen), and I. tabogae (Snyder) at 20-40 degrees C. Cyclic release of CO(2) was observed in 20-90% of C. cavifrons, 70-100% of I. tabogae, and 87-100% of I. minor pseudergates. Variability of the recordings (calculated as the coefficient of variability or CV) was used to estimate the level of cycling in each recording. CV ranged from 14.53+/-2.57 (40 degrees C) to 32.33+/-1.12% (30 degrees C) in C. cavifrons, 20.24+/-2.44 (35 degrees C) to 67.3+/-10.3% (20 degrees C) in I. minor, and 15.9+/-1.46 (35 degrees C) to 34.15+/-6.18% (20 degrees C) in I. tabogae. The relationship between temperature and CV for each species was modeled using non-linear regression. CV of both Incisitermes spp. decreased exponentially with temperature, while C. cavifrons CV followed a Gaussian model, indicating an optimal cycling temperature of approximately 30 degrees C. Mean V.CO(2) values were determined for each species as a function of temperature, and ranged from 0.1 ml CO(2) g(-1) h(-1) (I. minor at 20 degrees C) to 0.8 ml CO(2) g(-1) h(-1) (C. cavifrons at 40 degrees C). For all three species, V.CO(2) significantly increased linearly with temperature. Colinearity tests indicated that different models described the V.CO(2) relationship with temperature for both genera. Q(10) values for V.CO(2) over the range of 20-40 degrees C were 1.92 for I. minor, 1.66 for I. tabogae, and 1.62 for C. cavifrons pseudergates.     

Characterization of Chimeric Bacillus thuringiensis Vip3 Toxins

Bacillus thuringiensis vegetative insecticidal proteins (Vip) are potential alternatives for B. thuringiensis endotoxins that are currently utilized in commercial transgenic insect-resistant crops. Screening a large number of B. thuringiensis isolates resulted in the cloning of vip3Ac1. Vip3Ac1 showed high insecticidal activity against the fall armyworm Spodoptera frugiperda and the cotton bollworm Helicoverpa zea but very low activity against the silkworm Bombyx mori. The host specificity of this Vip3 toxin was altered by sequence swapping with a previously identified toxin, Vip3Aa1. While both Vip3Aa1 and Vip3Ac1 showed no detectable toxicity against the European corn borer Ostrinia nubilalis, the chimeric protein Vip3AcAa, consisting of the N-terminal region of Vip3Ac1 and the C-terminal region of Vip3Aa1, became insecticidal to the European corn borer. In addition, the chimeric Vip3AcAa had increased toxicity to the fall armyworm. Furthermore, both Vip3Ac1 and Vip3AcAa are highly insecticidal to a strain of cabbage looper (Trichoplusia ni) that is highly resistant to the B. thuringiensis endotoxin Cry1Ac, thus experimentally showing for the first time the lack of cross-resistance between B. thuringiensis Cry1A proteins and Vip3A toxins. The results in this study demonstrated that vip3Ac1 and its chimeric vip3 genes can be excellent candidates for engineering a new generation of transgenic plants for insect pest control.     

Survival of Escherichia coli in cowpats in pasture and in laboratory conditions

AIMS: To compare survival of Escherichia coli and faecal coliforms (FC) in bovine faeces deposited in a pasture or incubated in a controlled laboratory environment at temperatures within the same range. METHODS AND RESULTS: Faecal samples from three cow herds were deposited as shaded and nonshaded cowpats in a field and incubated in a laboratory for one month at 21.1, 26.7 and 32.2 degrees C. Both FC and E. coli concentrations increased as much as 1.5 orders of magnitude both in the field and in the laboratory during the 1st week and subsequently decreased. In shaded cowpats, the die-off of E. coli and FC was significantly slower, and the proportion of E. coli in FC was significantly larger as compared with nonshaded cowpats. The die-off was faster in the field than in the laboratory at similar temperatures. CONCLUSIONS: FC and E. coli die-off rates were substantially lower in laboratory conditions than in the field within the same range of temperatures. SIGNIFICANCE AND IMPACT OF THE STUDY: This study underscores the importance of field data on survival of manure-borne FC and E. coli, and indicates that laboratory die-off rates have to be corrected to be used for field condition simulations.     

Sero-epidemiological study of cowdriosis in Moorish zebu cattle from Senegal

The seroprevalence against heartwater for maure zebus coming from Mali and Mauritania is analysed by indirect ELISA using the major antigenic protein number 1-B (MAP1-B). Sero-epidemiological results realized on maure zebu cattle give a good adequation between the abundance or absence of the vector tick in the two countries for 98% of prevalence in Mali (infected area) and 0% of prevalence in Mauritania (non infected area).     

Production and secretion of resveratrol in hairy root cultures of peanut

Resveratrol and its derivatives are natural stilbenes associated with many health benefits that include those conferred by their antioxidant and anticancer properties. While stilbenes can be recovered as an extract from a selected number of plants, these products are not suitable for many applications in the food/pharmaceutical sectors due to high levels of impurities as well as the overall low concentration of resveratrol and its derivatives in the extract. To deliver a highly defined and enriched resveratrol product, hairy root cultures of peanut (Arachis hypogaea) were established and tested as a bioproduction system for resveratrol and associated derivatives. Analyses by HPTLC and GC-MS of ethyl acetate extracts showed that a single 24 h sodium acetate elicitation resulted in a 60-fold induction and secretion of trans-resveratrol into the medium of peanut hairy root cultures. trans-Resveratrol accumulated to levels of 98 microg/mg of the dried extract from the medium representing 99% of the total resveratrol produced. Other stilbenes, including trans-pterostilbene, were also detected in the medium. Our results demonstrate the capacity of hairy root cultures as an effective bioprocessing system for valued nutraceuticals like resveratrol and resveratrol derivatives. In being able to effectively induce and recover high levels of resveratrol and associated derivatives from the media fraction, hairy roots may offer a scalable and continuous product recovery platform for naturally-derived, high quality, enriched nutraceuticals.     

Impact of soil type, moisture, and depth on swede midge (Diptera: Cecidomyiidae) pupation and emergence

Contarinia nasturtii (Kieffer) (Diptera: Cecidomyiidae), a common insect pest in Europe and a new invasive pest in North America, causes severe damage to cruciferous crops. Currently, many counties in Canada and the United States in which C. nasturtii has not been previously reported are at risk of being infested by C. nasturtii. Effectiveness of chemical control is limited, especially under high population pressure in fields, because the cryptic habits of C. nasturtii protect them from insecticidal sprays. Alternative management strategies against C. nasturtii that are needed to protect crucifers and soil management for the pupal stage were studied as one option. Six different types of soils (loam fine sand, fine sand, clay loam, muck, Chenango shale loam, and silt loam soil) were collected from commercial cabbage fields in New York and studied in the laboratory for their impact on C. nasturtii pupation and emergence. The results indicated that extremely wet or dry soils significantly hindered C. nasturtii emergence, regardless of soil type, suggesting that soil type alone may not be a major factor regulating C. nasturtii abundance. Optimal moisture content for C. nasturtii emergence varied for different soils. Most C. nasturtii pupated within the top 1 cm of soil. Furthermore, we found that >5 cm of soil cover effectively reduced the emergence number and delayed the time of emergence. Based on these results, we suggest that soil manipulation (moisture content and cultivation practices) should be considered as an important component in an overall integrated pest management program for C. nasturtii.     

Fractal analysis of binding and dissociation kinetics and interactions of cancer markers on biosensor surfaces

A fractal analysis is presented for the binding and dissociation of different cancer markers on biosensor surfaces. The data analyzed include putrescine in solution to PDDA/APTES/MWCNT/Puo-modified GCE (glassy carbon electrode) (8) and vascular endothelial growth factor (VEGF) in solution to the soluble form of the VEGF receptor (SFlt-1 or VEGF-1) immobilized on a sensor chip (1). Single- and dual-fractal models were used to fit the data. Values of the binding and dissociation rate coefficient(s), affinity values, and the fractal dimensions were obtained from the regression analysis provided by Corel Quattro Pro 8.0 (13). The binding rate coefficients and the affinity values are sensitive to the degree of heterogeneity on the sensor chip surface. Predictive equations are developed for the binding rate coefficient as a function of the heterogeneity present on the biosensor chip surface. The analysis presented provides physical insights into these cancer biomarker-receptor reactions occurring on the different biosensor surfaces.