Effects of neem (Azadirachta indica) extracts onLeptocorisa chinensis under choice and no-choice conditions

Two extracts from neem (Azadirachta indica A. Juss. (Meliaceae)) seeds, azadirachtin and oil, and a mixture of neem oil and abamectin, were tested on second-instar nymphs of the rice bugLeptocorisa chinensis (Dallas) (Hemiptera: Alydidae). To clarify the effect of spraying coverage on bioefficacy of test materials, experiments were conducted under choice and no-choice conditions in field cages. In a choice test, treatment with the mixture of neem oil and abamectin was most effective in reducing the survival ofL. chinensis, followed by azadirachtin at 60 ppm, 30 ppm and 3% neem oil, whereas all treatments except neem oil caused 100% mortality within 3 weeks in a no-choice test. When second-instar nymphs had choices of treated and untreated plants within a treatment, no differences in yield and sum of dead and stained grains were found between those two choices, indicating that nymphs neither caused significant reduction in yield nor reduced the quality of untreated plants. Regardless of treatment, the difference in overall yield between treated and untreated plants under choice conditions was not statistically significant (P>0.05). Our results indicate that neem-based formulations, used alone or in combination with abamectin, have the potential to be integrated into the existing programs to control the rice bug. http://www.phytoparasitica.org posting Aug. 28, 2005.     

Somaclonal variation in Tricyrtis hirta plants regenerated from 1-year-old embryogenic callus cultures

The Liliaceous perennial Tricyrtis hirta, sometimes called ‘Japanese toad lily’, has recently become popular as an ornamental for pot and garden uses. Highly embryogenic callus cultures of this plant predominately consisted of diploid cells but also contained tetraploid cells after 1 year of establishment. In the present study, plans regenerated from the 1-year-old embryogenic callus cultures were subjected to ploidy level analysis and morphological characterization following 3 years of cultivation. Among 37 plants examined, 28 kept the diploid level (2n = 2x = 26) but nine were tetraploid (2n = 4x = 52) as indicated by FCM analysis and chromosome observation. Although no morphological alterations were detected in 26 out of 28 diploid regenerants, the remaining two showed noticeable variations: both were severely dwarf and had crimped leaves and many malformed flowers. The tetraploid regenerants had several horticulturally attractive characteristics compared with the diploid controls, such as longer shoots, thicker stems, and larger flowers. Thus regeneration of tetraploid plants from 1-year-old embryogenic callus cultures offers a possibility to improve the horticultural value of T. hirta, although regeneration of trueness-to-type plants is essential for utilizing the cultures for micropropagation and genetic transformation.     

Development of phototaxis in the early life stages of Pacific bluefin tuna <Emphasis Type="Italic">Thunnus orientalis</Emphasis>

We investigated the development of phototaxis in larval and early juvenile stages of Pacific bluefin tuna Thunnus orientalis to detail behavior development in relation to light. We observed the distribution of Pacific bluefin tuna in an illumination gradient tank from 1 to 26 days after hatching (DAH). Two long rectangular tanks (100 × 10 × 10 cm) were used for experiments; each tank was divided into four sections for observations and one tank was equally illuminated at 1.0 × 10³ lx as the control tank, and the other was at 4.0 × 10², 1.0 × 10³, 1.0 × 10⁴ and 7.0 × 10⁴ lx as the illumination gradient tank. Laboratory-reared larvae and juvenile were released into each tank and acclimatized for 10 min. Thereafter, the number of individuals in each section was counted for 5 times with 10-min intervals. Until 2 DAH (3.6 ± 0.1 mm BL), larvae distributed homogeneously in each section in both tanks. After 3 DAH (3.7 ± 0.1 mm BL) when the eyes of the larvae were pigmented, most fish moved into the 7.0 × 10⁴ lx section in the illumination gradient tank, while fish in the control tank maintained a uniform distribution during the experimental period (Chi-square test, P < 0.05). The results suggest that the post-larvae and juvenile stages show strong positive phototaxis.     

Improvement in the feeding activity, early growth and survival of Pacific bluefin tuna Thunnus orientalis larvae fed a casein peptide-based microdiet supplemented with inosine monophosphate

Two feeding experiments were conducted to determine the effect of a 5′-inosine monophosphate (IMP)-supplemented casein peptide-based microdiet (MD) on the feeding activity, growth and survival of Pacific bluefin tuna (PBT) larvae. PBT larvae [total length: 14.0 mm (Exp. 1) or 13.3 mm (Exp. 2)] were fed a casein peptide-based MD supplemented with or without 3% IMP for 12 days. As a negative control, a limited number of yolk-sac larvae of spangled emperor Lethrinus nebulosus were fed only for the first 7 days and starved for the next 5 days. A sufficient amount of yolk-sac larvae of spangled emperor was fed in the Exp. 2. All fish in the control group had died by 9 or 10 days after the experiment. Extensive mortality was observed in fish fed the MD. The MD was only found in the stomach contents of PBT fed the MD + IMP. Of the fish fed an IMP-supplemented diet, 50% survived for 12 days after the initiation of both feeding experiments. In addition, significantly higher growth than that observed during the first 7 days was seen in the PBT in the IMP treatment after 12 days of the feeding experiment. These results suggest that the supplementation of casein peptide-based MD with IMP could improve the feeding activity, survival and growth performance of PBT.     

Detection of granzyme B in CD3-positive cells infiltrated in lesional skin of a dog with erythema multiforme associated with zonisamide

In human erythema multiforme (EM), cytotoxic T lymphocytes (CTLs) play an essential role in the pathogenesis. In canine EM, immunohistochemical staining with anti-CD8 antibody using frozen sections has shown the involvement of CTLs; however, CTL infiltration has never been quantitatively analyzed. We herein quantitatively analyzed CTL infiltration by immunohistochemical staining with granzyme B and CD3 antibodies using paraffin sections of a dog with EM associated with zonisamide. The present results indicated approximately 70% of cells at the border between the epidermis and dermis consisted of CTLs. Detection of granzyme B and CD3 using paraffin sections employed in this study can be a clinically applicable method for detecting CTLs.     

Lokivetmab improved pruritus in a dog with cutaneous epitheliotropic lymphoma

A 13-year-old spayed female Cavalier King Charles Spaniel presented with chronic swelling and pruritus on the palmar aspect of the left forepaw and on the tail. Cutaneous epitheliotropic lymphoma (CEL) was diagnosed by histopathology and immunocytochemistry. Prednisolone was initially used alone as an alternative treatment for CEL. Despite long-term corticosteroid therapy, the patient’s physiological (pruritus) and dermatological signs (alopecia, erythema, erosion, and ulceration with crust) progressed and showed no evidence of improvement. To address the worsening condition of pruritus, lokivetmab was started in combination with prednisolone. Once on lokivetmab, the pruritus steadily improved and was effective in resolving and maintaining remission. Further investigation on the critical role of IL-31 in the pruritus pathway of dogs with CEL is required.     

Relationship between prey utilization and growth variation in hatchery‐reared Pacific bluefin tuna,Thunnus orientalis (Temminck et Schlegel), larvae estimated using nitrogen stable isotope analysis

In mass culture of Pacific bluefin tuna Thunnus orientalis, a marked growth variation is observed after they start feeding at 6–7 mm in body length (BL) on yolk‐sac larvae of other species, and the growth variation in tuna larvae is a factor leading to the prevalence of cannibalism. To examine the relationship between prey utilization and growth variation, nitrogen stable isotope ratios (δ¹⁵N) of individual larvae were analysed. A prey switch experiment was conducted under two different feeding regimes: a group fed rotifers (rotifer fed group), and a group fed yolk‐sac larvae of spangled emperor, Lethrinus nebulosus (fish fed group) from 15 days after hatching (6.87 mm BL). The fish fed group showed significantly higher growth than the rotifer fed group. Changes in the δ¹⁵N of the fish fed group were expressed as an exponential model and showed different patterns from those of the rotifer fed group. The δ¹⁵N of fast‐growing tuna larvae collected in an actual mass culture tank after the feeding of yolk‐sac larvae was significantly higher than those of the slow‐growing larvae, indicating that slow glowing larvae depended largely on rotifers rather than the yolk‐sac larvae.     

Total selenium content of agricultural soils in Japan

To evaluate the selenium (Se) level in agricultural soils in Japan and to investigate its determining factors, 180 soil samples were collected from the surface layer of paddy or upland fields in Japan and their total Se contents were determined. Finely ground soil (50 mg) was wet-digested with HNO₃ and HClO₄ solution and the released Se was reduced to Se(IV). The concentration of Se(IV) was then determined by high-performance liquid chromatography with a fluorescence detector after treatment with 2,3-diaminonaphthalene and extraction with cyclohexane. The total Se content ranged from 0.05 to 2.80 mg kg⁻¹ with geometric and arithmetic means of 0.43 and 0.51 mg kg⁻¹, respectively. The overall data showed a log-normal distribution. In terms of soil type, volcanic soils and peat soils had relatively high Se content and regosols and gray lowland soils had relatively low Se content. In terms of land use, upland soils had significantly higher Se content than paddy soils. Among regions, soils in the Kanto, Tohoku, Hokkaido and Kyushu regions had relatively high content. The total Se content had a significant positive correlation with the organic carbon content ( P  < 0.01) and the equation for the estimation of total Se content with organic carbon suggested that on average approximately 48% (0.24 mg kg⁻¹) of the total Se was in inorganic forms and approximately 52% (0.25 mg kg⁻¹) was in organic forms. Soil pH, on the contrary, did not show a significant relationship with the total Se content. In conclusion, the organic matter content, in combination with volcanic materials, was the main determining factor of the total Se content of agricultural soils in Japan.     

Detection of novel kobu-like viruses in Japanese black cattle in Japan

During surveillance for bovine diarrhea of unknown causes in Japanese black cattle in Kagoshima Prefecture, Japan, we found two types of novel kobu-like viruses in fecal samples of calves. Sequence analyses revealed that they had L protein and 2A protein with H-box/NC sequence motif, which are present in kobuviruses. Phylogenetic analysis revealed that they were related to kobuviruses; however, they clustered apart from other kobuviruses. In the prevalence study of two types of novel kobu-like viruses, 16.9% and 10.4% prevalence of these viruses were observed in the feces of diarrheal calves in this area.     

Polymeric procyanidins as radical-scavenging components in red-hulled rice

The extracts from white-, black-, and red-hulled rice were prepared by sequential extraction with six different polar solvents, and their radical-scavenging activities were measured by methods using 1,1-diphenyl-2-picrylhydrazyl radical (DPPH*) and tert-butyl hydroperoxyl radical (t-BuOO*). The extracts prepared with highly polar solvents, methanol and deionized water, exhibited higher DPPH* and t-BuOO* scavenging activities in all three cultivars. In addition, the acetone extract from red-hulled rice exhibited a high DPPH* and t-BuOO* scavenging activity, while no such activity was detected for the acetone extracts from white- and black-hulled rice. The major components responsible for the radical scavenging in the acetone extract from red-hulled rice were identified as procyanidins by acidic hydrolysis, vanillin assay, and Sephadex LH-20 chromatography. GPC analysis of the acetylated procyanidins revealed that the average molecular weight is about 5000, in a range of about 500-18,000.