Toxicity of spray and fumigant products containing cassia oil to Dermatophagoides farinae and Dermatophagoides pteronyssinus (Acari: Pyroglyphidae)

The toxicity of formulations of oil of cassia, Cinnamomum cassia Blume, (20 and 50 g L(-1) sprays and 100% oil-based fumigant) to adult Dermatophagoides farinae Hughes and D. pteronyssinus Trouessart was examined using contact and vapour-phase toxicity bioassays. Results were compared with the lethal activity of three commercial acaricides: benzyl benzoate, dibutyl phthalate and diethyl-m-toluamide (deet). The contact toxicity of cassia oil to both dust mite species was comparable with that of benzyl benzoate but was higher than that of the other two acaricides. Sprays containing 20 and 50 g L(-1) cassia oil were effective against both mite species when applied to fabric, glass, paper, plastic, tin or wood substrates. Applications of the 50 g L(-1) spray to different space volumes and surface areas determined that 50-60 mg of cassia oil was needed to control dust mites in 3.4 m(3) or in 1 m(2). In tests with fumigant devices, toxicity varied according to the thickness of non-woven fabric covering the device, the exposure time, the number of fumigant devices used and the volume of the space sprayed. Fumigant toxicity to adult D. pteronyssinus was more pronounced with devices enclosed in thinner (40 microm) versus thicker (45 or 50 microm) non-woven fabric covers. A single fumigant device with a 40 microm thick non-woven fabric cover resulted in substantial control in a space of 0.05 m(3) but exhibited only moderate to weak control in spaces >or= 0.097 m(3) at 4 days after application. Two fumigant devices gave 88% mortality in a space of 1.73 m(3). Cassia oil applied as sprays or in fumigant devices appears to provide effective protection of humans from house dust mites.     

Microscopic Particle Motions in Strongly Coupled Dusty Plasmas

The microscopic particle motions from the crystal to the disordered state of a dusty plasma with micrometer-sized silicon dioxide particle suspensions in a radio-frequency glow discharge system were studied through an optical microimaging system. Small-amplitude random motion around the lattice sites of the crystal state, relative domain motion with varying boundaries, cooperative hopping in the liquid state, and highly disordered motion with increasing radio-frequency power were observed. Chaotic states with different spatial scales under the coherent and stochastic coupling between dust particles and self-organized background plasma fluctuations were also demonstrated.     

Equatorial X-ray Emissions: Implications for Jupiter's High Exospheric Temperatures

Observations with the High Resolution Imager on the Rontgensatellit reveal x-ray emissions from Jupiter's equatorial latitudes. The observed emissions probably result from the precipitation of energetic (>300 kiloelectron volts per atomic mass unit) sulfur and oxygen ions out of Jupiter's inner radiation belt. Model calculations of the energy deposition by such heavy ion precipitation and of the resulting atmospheric heating rates indicate that this energy source can contribute to the high exospheric temperatures(>800 kelvin at 0.01 microbar) measured by the Galileo probe's Atmospheric Structure Instrument. Low-latitude energetic particle precipitation must therefore be considered, in addition to other proposed mechanisms such as gravity waves and soft electron precipitation, as an important source of heat for Jupiter's thermosphere.     

Metapopulation dynamics, abundance, and distribution in a microecosystem

The experimental fragmentation of landscapes of a natural ecosystem resulted in declines in the abundance and distribution of most species in the multispecies animal community inhabiting the landscapes and the extinction of many species. These declines caused the deterioration of the positive interspecific relation between local population abundance and distributional extent in this community. However, when patches were connected by habitat corridors, an immigration "rescue effect" arrested declines in both abundance and distribution and maintained the observed positive relation between them. These results demonstrate the importance of metapopulation dynamics and landscape connectivity for the persistence of populations in fragmented landscapes.     

Improvement in the in vitro Digestibility of Shrimp Meal by the Addition of Persimmon Peel

The present study was conducted to analyze the chemical properties of persimmon peel (PP) and the in vitro digestibility of shrimp meal (SM) diets containing PP. Discussions whether PP can be used as a feed additive to promote digestion of SM in chickens are also included. The chemical composition and chitinase activity of dried PP was studied. SM diets containing PP were formulated according to the 4 by 6 factorial design: 4 levels of SM (0%, 10%, 15%, and 20%) × 6 levels of PP (0%, 2%, 4%, 6%, 8%, and 10%). The in vitro digestibility of dry matter (IVDMD), crude protein (IVCPD), and chitin (IVCD) was also studied. PP was rich in nitrogen-free extract (NFE, about 74%) and tannin (2.8%), and the highest chitinase activity of PP was observed at pH 4.5. Approximately 50% of chitinase activity was also observed at acidic (3.0) and alkaline (8.0) pH. Its activity was slightly affected by pepsin treatment. IVDMD increased upon addition of up to 8% PP, but decreased with an increase in the level of SM. When PP level was increased up to 6%, IVCPD in the group containing 0% SM, changed slightly; however, an increasing trend was observed in the other groups. When PP level was more than 6%, IVCPD decreased in all the groups. IVCD increased dose-dependently with increasing level of PP and decreased with increasing level of SM. In conclusion, PP was rich in NFE, had high chitinase activity, and improved all digestibility parameters, such as IVDMD, IVCPD, and IVCD, in SM diets where the PP level was under 6%. Thus, up to 6% of PP can be safely included in SM diets as a digestion promoter.     

Biotransformation of an organochlorine insecticide,endosulfan, by Anabaena species

This study assesses the role of the blue-green algal species present in the soil in the dissipation of endosulfan and its metabolites in the soil environment. Two Anabaena species, Anabaena sp. PCC 7120 and Anabaena flos-aquae, were used in this study. Anabaena sp. PCC 7120 produced three principal biotransformation compounds, chiefly endosulfan diol (endodiol), and minor amounts of endosulfan hydroxyether and endosulfan lactone. Trace amounts of endosulfan sulfate were detected. In comparison, the biotransformation of endosulfan by Anabaena flos-aquae yielded mainly endodiol with minor amounts of endosulfan sulfate. An unknown compound was produced up to 70% from endosulfan spiked in the medium inoculated by A. flos-aquae after 8 days of incubation. Therefore, the endosulfan fate was dependent on the species. Within 1 day of incubation, two Anabaena species produced low amounts of beta-endosulfan after application of alpha-endosulfan. These results suggest the presence of isomerase in the Anabaena species. Further studies using a fermentor to control the medium pH at 7.2 to minimize chemical hydrolysis of endosulfan revealed a major production of endodiol with minor amounts of endosulfan sulfate and the unknown compound. These results showed that the production of the unknown compound might be dependent on the alkaline pH in the medium and that the production of endodiol by A. flos-aquae might be biologically controlled. This study showed that two algal species could contribute in the detoxification pathways of endosulfan in the soil environment.     

Intestinal morphology and enteral nutrient absorption of pigeon pea seed meal in piglets

This study was conducted to establish the relationship between histological alterations of the intestinal villus and intestinal function, and to histologically assess the enteral nutrient absorption of raw pigeon pea seed meal (PM). Piglets were allotted into five groups: feed withdrawal for 3 days or 5 days, refeeding soybean meal (SM) or PM for 2 days after the 3‐day fast, and access ad libitum to conventional feed for the last 2 days without fasting. After the end of each experiment, the intestinal segment and duodenum of each piglet were processed and examined by light and scanning electron microscopy, respectively. After fasting, villus height, cell area and cell mitosis number were decreased in most parts of each intestinal segment, and duodenal villus tips had a smooth surface. After refeeding SM or PM, the decrease in body weight improved, but there was not a significant difference between them. The atrophic morphology of the intestine was reversed by refeeding SM, suggesting that the intestinal villi might be activated by absorption of SM. On the other hand, in the piglets refed PM, the recovery of light microscopic parameters and duodenal villus tip morphology was less clear than with SM. The present histological results suggest that although the absorption of PM is less than that of SM, the PM nutrients might be effectively absorbed, even in the raw form, and establish that in pigs intestinal histological alterations correspond well with intestinal absorptive function.