Net depth response of a depth-controllable (towed) gillnet for fish sampling

SUMMARY: Flume-tank experiments were performed to examine the depth response of a new type of depth-controlled gillnet. Variations of net depth were investigated as the warp was paid out and wound up for different changes of warp length, main sinker weights, and winch speeds. In most experiments, when the warp finished paying out, the net continued to descend and then ascended slightly to an equilibrium depth (overshoot phenomenon). The overshoot distance was nearly constant when the warp was wound up and increased linearly with increasing winch speed when the warp was paid out. An increase in winch speed reduced net settling time, which converged on a constant value for both paying out and winding up.     

Development and characterization of monoclonal antibodies against canine trypsin

Canine cationic trypsin was purified by salting-out, gel filtration and affinity chromatography. Purity was confirmed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The molecular weight was ca. 28 kDa by SDS-PAGE.

Thirty hybridomas were obtained which produced mAb to canine cationic trypsin by the cell fusion technique. Twenty-two of these recognized cationic trypsin only, while eight hybridomas recognized both cationic and anionic trypsin. Several of the anti-canine cationic trypsin mAb were purified by salting-out and DEAE ion-change chromatography using ascites fluid of immunized BALB/c mice. The mAb proved to have very high specificity to canine cationic trypsin as shown by immunoblotting and it may be possible to use them to develop clinical assays.     

Hemagglutination and hemagglutination inhibition with Chuzan virus.

Chuzan virus agglutinated erythrocytes of several species of animals including bovine. The hemagglutinating (HA) activity against bovine erythrocytes was dependent on NaCl molarity and was expressed best at 0.6 M, but it was independent of pH and temperature. Three strains of Chuzan virus isolated from 2 cows and a pool of culicoides midges had indistinguishable HA antigenicity. All cattle infected with the virus developed high titers of hemagglutination inhibiting (HI) antibody which changed in parallel with neutralizing (NT) antibody titers. Correlation between HI and NT antibodies was very high and the antibodies persisted for one year or more. Therefore it was concluded that the HI test is applicable for survey of Chuzan virus infection among cattle in place of the NT test.     

Functional properties of oat globulin modified by a calcium-independent microbial transglutaminase

Oat globulin was modified by a calcium-independent microbial transglutaminase (TG). The TG-polymerized protein had higher solubility than the control at acidic pH and had improved water- and fat-binding properties. Incubation of 10% (w/v) oat globulin dispersions in the presence of TG at 37 degrees C led to the formation of a well-developed viscoelastic gel network with a microstructure characterized by thick strands and large clusters. The TG-induced gels had higher modulus values, lower loss tangent values, and lower frequency dependency than the heat-induced gels. The TG-induced gel system has the characteristics of classical polymer gel with permanent "chemical" cross-links, whereas the heat-denatured system has the characteristics of a temporary "physical" gel with breakable cross-links. Fourier transform infrared spectroscopy showed marked shift and intensity changes in several major bands, suggesting pronounced changes in protein conformation during TG-induced gelation. Aggregation of protein molecules was also indicated by the progressive increases in two infrared bands (1679-1682 and 1622-1625 cm(-)(1)) associated with the formation of intermolecular beta-sheets and strands. Results suggest that new food polymers with unique functionality can be produced from oat globulin treated with TG and that elastic gels can be formed near neutral pH, instead of the alkaline pH required for thermally induced oat globulin gels.     

Genetic and phylogenetic analysis of glycoprotein of rabies virus isolated from several species in Brazil

Genetic and phylogenetic analyses of the region containing the glycoprotein (G) gene, which is related to pathogenicity and antigenicity, and the G-L intergenic region were carried out in 14 Brazilian rabies virus isolates. The isolates were classified as dog-related rabies virus (DRRV) or vampire bat-related rabies virus (VRRV), by nucleoprotein (N) analysis. The nucleotide and amino acid (AA) homologies of the area containing the G protein gene and G-L intergenic region were generally lower than those of the ectodomain. In both regions, nucleotide and deduced AA homologies were lower among VRRVs than among DRRVs. There were AA differences between DRRV and VRRV at 3 antigenic sites and epitopes (IIa, WB+ and III), suggesting that DRRV and VRRV can be distinguished by differences of antigenicity. In a comparison of phylogenetic trees between the ectodomain and the area containing the G protein gene and G-L intergenic region, the branching patterns of the chiropteran and carnivoran rabies virus groups differed, whereas there were clear similarities in patterns within the DRRV and VRRV groups. Additionally, the VRRV isolates were more closely related to chiropteran strains isolated from Latin America than to Brazilian DRRV. These results indicate that Brazilian rabies virus isolates can be classified as DRRV or VRRV by analysis of the G gene and the G-L intergenic region, as well as by N gene analysis.     

Depth perception from image defocus in a jumping spider

The principal eyes of jumping spiders have a unique retina with four tiered photoreceptor layers, on each of which light of different wavelengths is focused by a lens with appreciable chromatic aberration. We found that all photoreceptors in both the deepest and second-deepest layers contain a green-sensitive visual pigment, although green light is only focused on the deepest layer. This mismatch indicates that the second-deepest layer always receives defocused images, which contain depth information of the scene in optical theory. Behavioral experiments revealed that depth perception in the spider was affected by the wavelength of the illuminating light, which affects the amount of defocus in the images resulting from chromatic aberration. Therefore, we propose a depth perception mechanism based on how much the retinal image is defocused.     

Low-magnetic-field control of electric polarization vector in a helimagnet

The mutual control of the electric and magnetic properties of a solid is currently of great interest because of the possible application for novel electronic devices. We report on the low-magnetic-field (for example, B values of +/-30 milliteslas) control of the polarization (P) vector in a hexaferrite, Ba2Mg2Fe12O22, which shows the helimagnetic spin structure with the propagation vector k0 parallel to [001]. The B-induced transverse conical spin structure carries the P vector directing perpendicular to both B and k0, in accord with the recently proposed spin-current model. Then, the oscillating or multidirectionally rotating B produces the cyclic displacement current via the flexible handling of the magnetic cone axis.     

Differences in lectin-binding properties between the common mucosal epithelium and follicle-associated epithelium in the rabbit small intestine

Differences in sugar distribution between the villous epithelium and follicle-associated epithelium (FAE) were compared using lectins in the rabbit small intestine. In every portion, villous columnar epithelial cells primarily exhibited a positive reaction to the GalNAc, GlcNAc, galactose, and oligosaccharide. In the ileal Peyer's patch (PP), whereas microvillous epithelial cells exhibited positive reactions, M cells tended to be negative. The villous epithelial reaction to the fucose group was negative, but M cells and microvillous epithelial cells showed a positive to the fucose. No epithelium had a positive reaction to the mannose and glucose. The variety of lectin-binding properties of villous epithelial cells and M cells may reflect specificity for the recognizing luminal substances such as antigenic molecules and bacterial elements.     

Relationship between the ultrasonographic findings of suspected superficial digital flexor tendon injury and the prevalence of subsequent severe superficial digital flexor tendon injuries in Thoroughbred horses: a retrospective study

The onset of severe injury to the superficial digital flexor tendon (SDFT) is extremely difficult to predict from slight changes in ultrasonographic findings in cases with no apparent clinical signs. This study investigated the relationship between an increased cross-sectional area (CSA) or edema in the subcutaneous tissue around the tendon and the subsequent onset of severe SDFT injury in Thoroughbred racehorses. Horses were classified into three groups based on ultrasound diagnosis (USD) findings: Group A included cases with enlarged tendons; Group B included cases with tendons of normal size but with prominent edema in the peritendinous tissue; and Group C (control group) included cases with no abnormal USD findings. The incidence of subsequent severe tendon injury was significantly higher in the horses in Groups A (25.7%, 28/101) and B (28.3%, 65/212) than in those in Group C (4.9%, 2/41). There were no significant differences in the median period and the median number of races from the first examination to the subsequent tendon injury between Groups A (140 days, 1 race) and B (120 days, 1 race). The results of this study revealed that horses with increased CSA and peritendinous edema are likely to suffer a subsequent severe tendon injury. Also, these two USD findings, i.e., increased CSA and peritendinous edema, indicate the risk of onset of severe SDFT injury.