Carry-over effects of dietary yeast RNA as a source of nucleotides on lymphoid organs and immune responses in Leghorn-type chickens

1. The carry-over effects of supplementing Leghorn-type chickens with yeast RNA as a dietary source of nucleotides for 4 weeks on growth, lymphoid organ weights and immune responses were assessed in a 12-week study. 2. A commercial starter feed supplemented with 0 (control), 5 (LR) or 10 (HR) g yeast RNA/kg was offered to 1-d-old male ISA Brown chicks for 4 weeks, and then all birds were given a commercial pullet grower feed for another 8 weeks. Growth performance, antibody responses to sheep red blood cells (SRBC) and cutaneous reactivity of toe webs to phytohaemagglutinin (PHA)-M were measured at 4-week intervals. 3. Growth rates, feed intake and feed efficiency were not affected by dietary yeast RNA during the supplementary period, but birds previously offered the HR diet grew faster than control birds during weeks 4 to 8.4. LR-fed birds had a higher spleen weight relative to body weight (BW) than control birds at week 4, but this effect was not detected at other times. 5. Serum primary antibody levels against SRBC were not affected by dietary yeast RNA at any time. 6. The toe-web PHA response was significantly higher at week 8 in control birds than in birds previously given the LR diet, although no difference among dietary treatments was observed at other times. 7. It is concluded that the addition of yeast RNA as a source of nucleotides to a commercial diet selectively stimulated the development of the spleen in young birds, but this effect did not persist into a later stage of the bird's life.     

Pansteatitis in a free-ranging red-tailed hawk (Buteo jamaicensis).

A free-ranging juvenile female red-tailed hawk (Buteo jamaicensis) that was unable to fly was admitted to a rehabilitation center and died 1 day later. Hematology and serum chemistry abnormalities included moderate regenerative anemia, elevated creatine kinase, and hyperphosphatemia. Necropsy revealed a generalized steatitis, and histology showed a necrotizing and granulomatous pansteatitis with intralesional pigment compatible with ceroid. There was also moderate diffuse myodegeneration, mild multifocal cardiomyopathy, and mild multifocal hepatic necrosis. These changes and lesions resemble those caused by vitamin E deficiency in mammals and fish-eating birds.     

Manufacture and properties of high-performance oriented strand board composite using thin strands

Three-layered composite oriented strand boards were manufactured using very thin hinoki (Japanese cypress, Chamaecyparis obtusa Endl.) strands oriented in the faces and mixtures of sugi (Japanese cedar, Cryptomeria japonica D. Don.) and hinoki particles in the core. The boards were composed of two density levels, with 1:8:1, 0.5: 9 : 0.5, and 0: 10 : 0 face: core: face ratios. Polymeric and emulsion type isocyanate resins were used. The resin contents for the strands in the face and particles in the core were 10% and 5%, respectively. The steam-injection press was applied at 0.62MPa (160°C), and the steam-injection time was 2min. The mechanical and physical properties of the boards were evaluated based on the Japanese Industrial Standard. The parallel moduli of rupture and elasticity along the strand orientation direction and the wood screw retaining force increased with increasing face/core ratios. Incorporation of 10%–20% of thin strands in the face of the boards improved the parallel moduli of rupture and elasticity by 47%–124% and 30%–65%, respectively. In addition, the thickness swelling after water-soaking at 20°C for 24h, and the parallel linear expansion after boiling for 2h and water-soaking at 20°C for 1 h, of the three-layered composite boards were below 8% and 0.15%, respectively, despite a short steam-injection press time. The thickness swelling of the boards decreased with increasing face/core ratios. In contrast, the presence of face strands seems to have a minimal effect on the moduli of rupture and elasticity along the perpendicular direction of the three-layered composite boards. A similar trend was observed for the internal bond strength, hardness, and linear expansion along the perpendicular direction.This paper was presented at the 47th annual meeting of the Japan Wood Research Society, Kochi, April 1997     

Effects of mat moisture content and press closing speed on the formation of density profile and properties of particleboard

Isocyanate resin-bonded 0.5 and 0.7 g/cm³ lauan (Shorea sp.) particleboards were produced from mats with uniform and distributed moisture content (MC) distributions, using three hot press closing speeds. The effects of these processing variables on the formation of density profile in particleboard and board properties were analyzed statistically. A definition of the density profile was introduced, and the correlations among the various defining factors were established. The results are summarized as follows. (1) The peak density (PD) of particleboard could be increased, with a slight reduction in the core density (CD), using mats with different MC distributions. (2) In a conventional density profile, CD and PD are highly dependent on the board mean density (MD); and the gradient factor (GF), peak distance from the faces (Pdi), and peak base (Pb) are significantly correlated to each other, at the 99% significance level. (3) Greater press closing speed reduces Pdi and Pb, with an increase in GF. (4) Greater press closing speed could increase the PD in board of low MD, with minimal effect on CD. (5) The modulus of elasticity (MOE) of particleboards from mats with high MC near the faces were consistently higher than those from mats with uniform MC, irrespective of the press closing speed, whereas their modulus of rupture (MOR) became indifferent at higher MD under slow and fast closing speeds. (6) Sanding does not improve the MOR and MOE of particleboard significantly.     

雷竹红天牛的观察和防治

雷竹红天牛是近年发现的为害雷竹枝、秆的新害虫,对其为害状况、形态特征和生物习性作了较详细的观察和调查,并提出相应的防治办法。     

Phage-displayed peptide ligands for pancreatic alpha-amylase cross-react with barley alpha-amylase.

Peptide ligands that bind to pancreatic alpha-amylase were isolated from bacteriophage libraries displaying random 15-mer peptides by iterative affinity selection and amplification. The DNA sequences of selected clones from the final round of biopanning were determined. The two phage-display ligands with high-binding activities contained a high content of Arg, Tyr, and Trp residues with the short consensus sequence Arg-X-Tyr-Trp. These clones were shown to exhibit comparable binding interactions toward barley alpha-amylase based on transducing units titering and measurement of the dissociation constants.     

Toxicological effects of microcystin-LR on earthworm (<Emphasis Type="Italic">Eisenia fetida</Emphasis>) in soil

Microcystin-LR (MC-LR) is a cyclic heptapeptide toxin produced by cyanobacteria in eutrophic water. It can be transferred into soil–crop systems via irrigation and cyanobacterial paste fertilization. No studies have examined the potential toxicity of MC-LR to soil animals. Therefore, in the present study, the toxicological effects of MC-LR on earthworm (Eisenia fetida), including survival, growth, reproduction, oxidative stress, and cell viability, were investigated. The LC₅₀ of MC-LR was 0.149 μg cm^?2 at 72 h based on a filter paper test and 0.460 mg kg^?1 at 14 days based on an acute soil test. MC-LR seriously affected the reproduction of earthworms. Based on hatchability, the EC₅₀ of MC-LR was 0.268 mg kg^?1, similar to environmentally relevant concentrations of microcystins. The changes in activities of superoxide dismutase, guaiacol peroxidase, catalase, and glutathione peroxidase, together with the levels of glutathione and malondialdehyde, indicated that oxidative damage and lipid peroxidation played significant roles in MC-LR toxicity. In addition, the toxicity of MC-LR in earthworms increased despite degradation of MC-LR in soil over time, possibly due to the formation of toxic metabolites of MC-LR or the bioaccumulation of MC-LR in earthworms. A reduction in the neutral red retention time along with an increase in coelomocyte apoptosis with increasing MC-LR concentrations indicated a severe damage to viability. These results suggest that environmentally relevant MC-LR concentrations in agricultural soil may cause reproductive, biochemical, and cellular toxicity to Eisenia fetida. This information can be used in ecological risk assessments on MC-LR in soil.     

Functional partition of cells in the gill epithelium of the Japanese eel, Anguilla japonica, and the role of hormones

Viable chloride and pavement cells were isolated from the gill epithelium of Japanese eel, Anguilla japonica, by a 3-step percoll gradient centrifugation at low speed. Viability of the isolated cells were tested by the trypan blue exclusion test, rhodamine-123, or pre-labelling the cells with fluo-3 Ca²⁺ dye and examined by laser confocal microscopy. Isolated chloride cells responded to ionomycin with a rapid increase in Ca²⁺ fluorescence, which was abolished by chelating external Ca²⁺ with EGTA. Peptide hormones, including arginine vasotocin, isotocin, insulin-like growth factor I and II, and urotensin I increased Ca²⁺ entry, urotensin II had no effect, and eel corpuscles of Stannius extract reduced residual Ca²⁺ fluorescence. Isolated chloride cells and pavement cells from eels were analyzed for their enzymatic activities involved in intermediary and nitrogen metabolism. Chloride cells had high levels of glutaminase I, glutamate dehydrogenase, glutamate oxalacetate transaminase, HCO₃-ATPase and carbamoyl phosphate synthetase II. Pavement cells had highly active glucose-6-phosphate dehydrogenase and AMP deaminase. Both had high levels of lactate dehydrogenase compared with other tissues.