Availability of culture filtrate protein-10 (CFP-10) secreted from Mycobacterium pseudoshottsii for mycobacteriosis diagnosis in ginbuna crucian carp Carrasius auratus langsdorfii

Mycobacteriosis in cultured fish is a challenge for the aquaculture industry worldwide. Treatment by chemical administration is difficult and no effective vaccine has been developed. Therefore, detection and isolation by early diagnosis are important for prevention of the spread of the disease. In mammals, interferon gamma release assays have been established for detection of tuberculosis; these tests are based on the delayed-type hypersensitivity (DTH) response against culture filtrate protein-10 (CFP-10) and the 6-kDa early secreted antigen target (ESAT-6) of Mycobacterium tuberculosis. On the other hand, little is known about the fish immune response against the ESAT-6 and CFP-10 proteins of mycobacteria, although these responses should find application in the diagnosis of mycobacteriosis in fish. In the present study, we identified ESAT-6 and CFP-10 from Mycobacterium pseudoshottsii and cloned the corresponding genes. Intraperitoneal injection of the corresponding DNA plasmid constructs in ginbuna crucian carp yielded increased expression of the fish interferon-γ1-1-encoding gene (IFN-γ1-1). In contrast, IFN-γ1-1 expression accompanied by DTH response was observed only in the CFP-10-DNA plasmid-injected fish. Furthermore, fish that had been prophylactically injected with CFP-10-DNA plasmid exhibited increased survival of M. pseudoshottsii infection. Taken together, these results suggested that CFP-10 may facilitate diagnosis of mycobacteriosis.     

Fish meal replacement by soy protein from soymilk in the diets of red sea bream (Pagrus major)

Six isoenergetic diets were formulated as follows: fish meal (FM) 700 g kg^–1 (control, C), FM 300 g kg^–1 + soy protein concentrate 300 g kg^–1 (SPC), FM 300 g kg^–1 + enzyme‐treated SPC 300 g kg^–1 (ESC), FM 170 g kg^–1 + soy protein isolate 300 g kg^–1 (SPI), FM 160 g kg^–1 + enzyme‐treated SPI 300 g kg^–1 (ESI) and FM 150 g kg^–1 + conglycinin 300 g kg^–1(CG). Forty fish (3.9 g) were randomly distributed into each of eighteen 300‐L tanks, fed twice daily until satiation for 8 weeks. The final body weight, specific growth rate and condition factor did not show significant differences among the fish fed with diets C, SPC, ESC and ESI (p > .05). The survival was significantly lower in fish fed with diets SPI and CG. Feed efficiency was significantly higher in fish fed with diets SPC and C than in fish fed with other diets (p < .05). There were no significant differences in nutrients retention efficiencies in fish fed with diets C, SPC, ESC and ESI. A significantly higher phosphorus retention efficiency in fish fed with soymilk protein diets resulted in lower phosphorus discharge to the environment (p < .05). These results suggest that the soymilk proteins can comfortably replace 570–770 g FM kg^–1 diet of red sea bream juvenile, which will ensure significant ecological benefits through reducing phosphorus load to the environment.     

Amylose synthesis capacity of the three Wx genes of wheat cv. Chinese Spring

The Wx locus controls amylose synthesis in the cereal endosperm. Hexaploid wheat (Triticum aestivum L.) has the three Wx loci on chromosomes 7A ( Wx-A1), 4A (Wx-B1) and 7D (Wx-D1). To verify the effects of null alleles on reducing amylose content and determine the amylose synthesis capacity of each Wx gene independently and accurately, we produced eight possible types of recombinant lines carrying different null alleles at the Wx loci under the ‘Chinese Spring’ genetic background. Amylose content varied from 0% of the waxy ‘Chinese Spring’ to 25% of the ‘Chinese Spring’ normal type. The reducing effect of the single null alleles was the largest in Wx-B1b, and there was no significant difference between Wx-A1b and Wx-D1b. More than 3% reductions in amylose content were detected in the double null types. The results of the double null lines further demonstrated that for the capacity of amylose synthesis, Wx-B1a predominates and produces 21–22% amylose, followed by Wx-D1a (20–21%) and Wx-A1a (15–18%). These significant differences were partly correlated with variation in the amounts of the Wx proteins produced by different Wx genes. However, comparisons of the double null lines with the single null or normal lines indicated that amylose content was not linearly proportional to the number of the Wx genes, suggesting that the Wx genes act in an epistatic manner. This revised version was published online in July 2006 with corrections to the Cover Date.     

Spleen-Specific Development of Germinal Centers in Rats Treated with Antithyroid Drugs

The antithyroid drugs (ATDs) methimazole (MMI) and propylthiouracil (PTU) have been used for treatment of hyperthyroidism for more than several decades, despite the fact that they are associated with adverse drug reactions that are thought to be autoimmune mediated. We therefore examined histopathologic responses in the immune system in male and female rats given MMI (2, 20 and 200 mg/kg/day, p.o., in experiment 1; 200 mg/kg/day, p.o., in experiment 3) or PTU (25 and 250 mg/kg/day, p.o., in experiment 2; 200 mg/kg/day, p.o., in experiment 3) for two weeks. In experiments 1 and 2, highest doses of MMI and PTU induced histopathologic changes in the spleen consistent with those in experiment 3 without any changes in the other peripheral lymphoid organs and tissues. In experiment 3, histopathological evaluation of the spleen along with hematological and bone marrow examinations were performed. In both male and female rats, MMI or PTU induced histopathological changes in the spleen characterized by development of germinal centers and an increase in the number of IgG-positive plasma cells in the red pulp; these changes were most prevalent in the MMI-treated female rats. Total red and white blood cell counts were decreased in the MMI-treated male and female rats; lymphocytes and monocytes were lower in male and female rats, respectively. Bone marrow nucleated cells were significantly lower in the MMI-treated males. This is the first study to demonstrate that ATDs induce spleen specific B-cell reactions in rats     

Effect of monoenergetic neutron irradiation on the postnatal development of the cochlea in C3H/HeN mice

To investigate the toxic effect of neutrons at energies of approximately 1MeV on the ear, we exposed 7-day-old mice to 1.0 Gy of monoenergetic neutrons (1.026 MeV) or (137)Cs gamma rays, and assessed subsequent morphological changes in the inner ear by light and scanning electron microscopy. Monoenergetic neutrons, but not gamma rays, caused acute changes in the ear. The epithelium of the greater epithelial ridge in the organ of Corti had disappeared by 72 hr post-irradiation, as a result of epithelial apoptosis observed 6 hr post-irradiation. Radiation could induce apoptotic cell death of the epithelium of the greater epithelial ridge at 3 or 4 days of age. Protruding structures were detected on the surface of the hair cells by 72 hr post-irradiation. The neutron-irradiation also caused the apoptotic cell death of epithelial cells at the nasal conchae, and subsequent acute otitis media continued until 10 weeks of age.     

Windthrow resistance of apple trees grafted in an orchard

Pull-down tests were conducted for apple trees grafted in an orchard and for support posts in order to discuss the failure mode in windthrow damage, the effect of rootstock types on the uprooting strength, and the reinforcing effect of support posts on young trees. The test samples were ten mature trees (20–23 years old) of three varieties grafted on two types of rootstocks, three young trees (7 years old) grafted on dwarf rootstocks, and nine support posts of larch logs and steel pipes. The failure modes were found to be uprooting for mature trees and rootstock breakage for young trees. The uprooting strength of apple trees was considerably smaller than the uprooting strength of forest trees reported in previous studies. However, the windthrow resistance of the apple trees with respect to the critical wind velocity was estimated to be sufficient despite their low uprooting strength because of their small height. Young trees should be supported with wooden posts for a few years after grafting so that they acquire sufficient windthrow resistance. Part of this study was published in the report for the Grant-in-Aid for Collaborative Research by NOASTEC (No. H17-kyo-048)     

Feasibility of improved slotted bolted connection for timber moment frames

This note examines the feasibility of an improved slotted bolted connection for timber moment frames. In the improved connection, steel tubes are inserted into drill holes in glulam and fixed to the glulam with resin injection. Aluminum splice plates with curved slots, or curved elongated holes, are fastened mechanically by using high-strength bolts that go through the steel tubes. Since the compression due to bolt tension is fully supported by the steel tubes, the reduction of bolt tension due to shrinkage of the glulam can be avoided. The use of slotted aluminum splice plates allows stable energy dissipation due to smooth sliding between the aluminum splice plates and the end surfaces of the steel tubes within the specified range of rotation angle. Through quasistatic cyclic loading tests of two connection specimens, it was demonstrated that stable and nearly rigid-plastic hysteresis loops were obtained whose equivalent viscous damping ratio was more than 30% in the range of rotation angle close to or greater than 1/50 radian. Although further improvement is necessary, the experimental results demonstrate the feasibility and potential of the present connection.     

Fine-root dynamics in a young hinoki cypress (<Emphasis Type="Italic">Chamaecyparis obtusa</Emphasis>) stand for 3 years following thinning

Fine roots play a key role in carbon and nutrient dynamics in forested ecosystems. Fine-root dynamics can be significantly affected by forest management practices such as thinning, but research on this topic is limited. This study examined dynamics of fine roots <1 mm in diameter in a 10-year-old stand of hinoki cypress (Chamaecyparis obtusa) for 3 years following thinning (65% in basal area). Fine-root production and mortality rates were estimated using a minirhizotron technique in combination with soil coring. In both thinned and un-thinned control plots, fine-root elongation occurred from early spring to winter (March to December) and fluctuated seasonally. In the thinned and the control plots, the annual fine-root production rates were estimated to be 101 and 120 g m⁻² year⁻¹, respectively, whereas the estimated annual fine-root mortality rates were 77 and 69 g m⁻² year⁻¹, respectively. At 3 years after thinning, live fine-root biomass was significantly smaller in the thinned plot (143 g m⁻²) than in the control plot (218 g m⁻²), whereas dead fine-root biomass was not (147 and 103 g m⁻², respectively). Morphological and physiological indices of fine roots such as diameter, specific root length, and root tissue density of the live fine roots was similar in both plots. These results suggested that thinning tended to decrease biomass and production of fine roots, but the effects on characteristics of fine roots would be less evident.     

Technical note: development of a duodenal cannula for sheep.

A single T-shaped duodenal cannula of silicone rubber with a gutter-type small inner flange was developed for sheep. The barrel of the cannula was 24 mm long with an internal diameter of 12 mm. A polyester surgical mesh (100 mm x 100 mm) was connected to the barrel of the cannula as an anchor. Fibrous tissues grew on the polyester mesh anchor and adhered firmly to the serosa of the intestine, thus leaving no gap and, hence, preventing any leakage of intestinal contents from the side of the fistula. The small (24 mm in diameter) and thin (3 mm in thickness) outer flange of the cannula became buried in the wool and prevented any mechanical disturbance of the cannula by the activity of the animal. The elasticity of the silicone rubber prevented distortion of the duodenum around the barrel of the cannula. No erosion of the tissue between the inner flange of the cannula and the mesh was seen in postmortem observations.