Development and reproduction of five Tetranychus species (Acari: Tetranychidae): Do they all have the potential to become major pests?

The objective of this study was to investigate whether four spider mite species, Tetranychus ludeni, T. phaselus, T. piercei and T. truncatus, currently with insignificant economic impact, have the potential to achieve the same status as T. urticae, which until now has been considered as the most serious tetranychid pest species in orchards and greenhouses. We investigated the effect of temperature on development, survival and oviposition at 11 constant temperatures ranging from 15 to 40 °C at intervals of 2.5 °C and estimated demographic parameters, such as the intrinsic rate of natural increase (rm), for these five species at five constant temperatures. Developmental time from egg to adult (female and male) decreased with increasing temperature from 15 to 32.5 °C in all five species, but increased slightly at 35 °C or higher, especially in T. ludeni and T. urticae. Using linear and non-linear developmental rate models, the lower thermal thresholds for egg-to-adult (female and male) and egg-to-egg development were found to range from 9.8 to 11.7 and from 9.8 to 11.4 °C, respectively. The intrinsic optimal temperature (TΦ) ranged from 18.0 to 27.4 °C for egg-to-female adult and from 23.9 to 27.2 °C for egg-to-egg development. The oviposition period and adult longevity were strongly affected by temperature. The rm-values increased with increasing temperature from 15 to 30 or 35 °C in all five species. The highest rm-values at each temperature were 0.114 day(-1) at 15 °C for T. ludeni, 0.199 day(-1) at 20 °C for T. urticae, 0.314 day(-1) at 25 °C for T. ludeni, 0.451 day(-1) at 30 °C for T. ludeni and 0.433 day(-1) at 35 °C for T. truncatus. The total fecundity, net reproductive rate (R0) and rm of T. ludeni were higher than those of T. urticae at all temperatures. T. piercei and T. truncatus showed higher rm-values at 30 and 35 °C than T. urticae. The results indicate that the former three species are better adapted to hot weather than T. urticae and have a high potential to become serious pests.

Effect of dietary soy protein on tumor necrosis factor productivity in macrophages from nephritic and hepatoma-bearing rats.

The present study investigated the effect of dietary soy protein isolate (SPI) on tumor necrosis factor-alpha (TNF) productivity in peritoneal macrophages from nephritic and hepatoma-bearing rats. Dietary SPI significantly inhibited the elevated production of TNF by lipopolysaccharide-stimulated macrophages in nephritic and hepatoma-bearing rats compared with dietary casein, while it exerted no influence on the TNF productivity in normal rats. Removal of the minor components contained in SPI by ethanol extraction could significantly or partially restore the reduced TNF production caused by SPI in nephritic and hepatoma-bearing rats, respectively. These results suggest that dietary SPI could suppress the enhanced productivity of TNF associated with the progression of nephritis and hepatoma, and some factors existing in the ethanol extract of SPI are suggested to be involved in suppressing TNF productivity by macrophages.

Fibril-like aggregate formation of peptide carboxylate Langmuir films analyzed by surface pressure, surface dipole moment, and infrared spectroscopy.

The fibril formation process of a synthetic peptidolipid compound in a Langmuir monolayer at the air-water interface has been analyzed by surface pressure and surface dipole moment-area isotherms, followed by infrared spectral analysis of related Langmuir-Blodgett films. Thus far, the analysis of randomly oriented molecular assemblies has been a difficult matter, especially for spectroscopic measurements. In the present study, the Langmuir film isotherms were discussed in detail, and they have readily been correlated to the infrared spectra. For the spectral analysis, infrared multiple-angle incidence resolution spectroscopy (MAIRS) was employed, which was compared to the results by conventional techniques. Since the peptide assemblies greatly responded to a metal surface, the reflection-absorption technique was not useful for our analysis. Instead, MAIRS was found to be powerful to reveal the anisotropic structure of the Langmuir films, and a disordered molecular architecture has been revealed via the molecular orientation analysis. As a result, the fibril-like aggregation formation process during the monolayer compression, which was suggested by previous topographical study, has been found to be due to the stiff domain formation in the Langmuir films.