Contribution of active defense responses in the limitation of fungal spread in the sapwood of living sugi (Cryptomeria japonica) tree

The participation of active defense responses in the limitation of fungal spread in the sapwood of living sugi tree was determined. Isolates ofGuignardia cryptomeriae were inoculated to living trees, fresh logs, frozen and thawed logs and autoclaved logs, and the spread of wood discoloration and fungal hyphae was assessed. In autoclaved logs and freeze-treated logs, wood discoloration and reaction zone formation were not observed, and fungal hyphae of both of virulent and avirulent isolates grew rapidly in the wood. In fresh logs, wood discoloration and the formation of a pale reaction zone and transition zone were observed. Virulent isolates spread rapidly, but the spread of avirulent isolates was inhibited. In living trees, wood discoloration was observed and reaction zones were formed at lesion margins. These results indicated that constitutive defense mechanisms had no effect on the spread of both of virulent and avirulent isolates, and that active defense responses were important in the limitation of spread of fungal hyphae, hence in the limitation of wood discoloration. Further, it appeared that avirulent, but not virulent, races ofG. cryptomeriae were easily inhibited even by weak host responses. This study was presented at 105th and 106th Annual Meeting of the Japanese Forestry Society.     

Binding of mammalian and avian ferritins with biotinylated hemin: demonstration of preferential binding of the H subunit to heme

The binding of ferritin to heme has been well studied using commercial horse spleen apoferritin, which is almost entirely composed of the L subunit, suggesting that mammalian ferritins bind heme. The present study revealed that both mammalian holoferritins (commercial horse spleen ferritin and purified horse spleen, bovine spleen and canine liver ferritins with L/H subunit ratios of 4.0, 1.1, and 2.3, respectively) and their apoferritins bound biotinylated hemin; apoferritins had higher binding activity than holoferritins, except for canine holo- and apoferritins, which showed the same binding. Bovine ferritin H subunit homopolymers expressed by a baculovirus expression system showed heme binding and had higher binding activity to biotinylated hemin than the L subunit homopolymer expressed by the same system. These bindings were inhibited by heme but not by iron-free or Zn-protoporphyrin IX (Zn-PPIX). Purified chicken liver holoferritin was found to be composed of only H subunits and showed the highest binding activity with biotinylated hemin compared with mammalian holoferritins. The binding of chicken liver holoferritin to biotinylated hemin was also inhibited by heme but not by PPIX or Zn-PPIX. These results indicate that mammalian and avian ferritins bind heme and that the H subunit preferentially recognizes heme.     

Areolae of the Placenta in the Antarctic Minke Whale (Balaenoptera bonaerensis)

In this study, we examined the existence and structure of areolae and the steroidogenesis of areolar trophoblast cells in the Antarctic minke whale placenta morphologically and immunohistochemically. Placentas were collected from the 15th, 16th and 18th Japanese Whale Research Program under Special Permit in the Antarctic (JARPA) and 1st JARPA II organized by the Institute of Cetacean Research in Tokyo, Japan. The opening and cavity of fetal areolae formed by taller columnar trophoblast cells (areolar trophoblast cells) with long microvilli and a bright cytoplasm, as compared with the trophoblast cells of the chorionic villi interdigitating with the endometrial crypts, were recognized in observations of serial sections. The opening of the areolar cavity was hidden by chorionic villi with areolar trophoblast cells. Furthermore, a closed pouch-like structure lined by tall columnar cells similar to areolar trophoblast cells within the stroma of chorionic villi was noticed and continued to the areolar cavity, with the opening seen on serial sections. In a surface investigation of the chorion and endometrium by SEM, maternal (endometrial) areolae irregularly surrounded by endometrial folds were obvious. Moreover, we distinguished areolar trophoblast cells with long microvilli attached with many blebs from trophoblast cells. In our immunohistochemical observations, a steroidogenic enzyme, cytochrome P450 side chain cleavage enzyme (P450scc), was detected with strong immunoreactivity in trophoblast cells. However, areolar trophoblast cells showed weak or no immunoreactivity for P450scc.     

Correlated responses of respiratory disease and immune capacity traits of Landrace pigs selected for Mycoplasmal pneumonia of swine (MPS) lesion

Five generations of Landrace pigs selected for average daily gain, backfat thickness, Mycoplasmal pneumonia of swine (MPS) lesion score, and plasma cortisol levels, was executed to decrease the MPS lesion score. Genetic parameters and correlated genetic responses for respiratory disease and peripheral blood immune traits were estimated in 1395 Landrace pigs. We estimated the negative genetic correlation of MPS lesion score with phagocytic activity (PA) at 7 weeks of age (‐0.67). The breeding values of PA at 7 weeks of age and 105 kg body weight and the correlated selection response of the ratio of granular leukocytes to lymphocytes at 105 kg body weight were significantly increased, and sheep red blood cell‐specific antibody production (AP) was significantly decreased in a selection‐dependent manner. Increasing of natural immunological indicators (e.g. PA) and decreasing of humoral immunological indicator (e.g. AP) were observed due to genetically decreasing MPS lesion score.     

Characteristics of various fibrolytic isozyme activities in the rumen microbial communities of Japanese Black and Holstein Friesian cattle under different conditions

Rumen microorganisms produce various fibrolytic enzymes and degrade lignocellulosic materials into nutrient sources for ruminants; therefore, the characterization of fibrolytic enzymes contributing to the polysaccharide degradation in the rumen microbiota is important for efficient animal production. This study characterized the fibrolytic isozyme activities of a rumen microbiota from four groups of housed cattle (1, breeding Japanese Black; 2, feedlot Japanese Black; 3, lactating Holstein Friesian; 4, dry Holstein Friesian). Rumen fluids in all cattle groups showed similar concentrations of total volatile fatty acids and reducing sugars, whereas acetic acid contents and pH were different among them. Predominant genera were commonly detected in all cattle, although the bacterial compositions were different among cattle groups. Zymograms of whole proteins in rumen fluids showed endoglucanase activities at 55 and 57 kDa and xylanase activity at 44 kDa in all cattle. Meanwhile, several fibrolytic isozyme activities differed among cattle groups and individuals. Treponema, Succinivibrio, Anaeroplasma, Succiniclasticum, Ruminococcus, and Butyrivibrio showed positive correlations with fibrolytic isozyme activities. Further, endoglucanase activity at 68 kDa was positively correlated with pH. This study suggests the characteristics of fibrolytic isozyme activities and their correlations with the rumen microbiota.     

Characterization of monoclonal antibodies against Actinobacillus pleuropneumoniae serotype 5.

Two monoclonal antibodies against Actinobacillus pleuropneumoniae serotype 5, designated as 5MAb-1 and 5MAb-6, were characterized. Enzyme-linked immunosorbent assay-inhibition tests with whole-cell antigens obtained from strains of serotype 1 through 12 of A pleuropneumoniae revealed that 5 MAb-1 bound to only serotype-5 strains. The epitope recognized by 5MAb-1 was a carbohydrate that was sensitive to periodate oxidation and resided on the structure of beta-1,6-linked D-galactose in an O-antigen polysaccharide of serotype-5 lipopolysaccharide. Analysis of these results revealed that the O-antigen polysaccharide of lipopolysaccharide was 1 of the antigenic determinants responsible for the serotype specificity of A pleuropneumoniae. On the other hand, 5MAb-6 reacted with strains of serotype 1 through 10 in varying degrees and its epitope was located on polypeptides sensitive to proteinase K. In an immunoblotting analysis, 5MAb-6 reacted with 2 polypeptide bands, with molecular weights of approximately 41,500 and 28,000, in the outer membrane protein-rich fraction obtained from strains of serotype 1 through 10. These results indicated that outer membrane proteins from several serotype strains of A pleuropneumoniae possessed common antigenic determinants.     

In vitro infection of fractionated chicken lymphocytes by infectious bursal disease virus

Lymphocytes from bursa of Fabricius and thymus of chickens were purified and separated into the three cell subsets--T, B, and null cells--by the techniques of nylon fiber columns and cytotoxicity tests. The in vitro susceptibility of the fractionated lymphocytes to a virulent strain of infectious bursal disease virus (IBDV) was studied by using immunofluorescence as the infection criterion. B cells were highly susceptible. By contrast, T cells and null cells were insusceptible to infection by IBDV. The relationship between the target cells for virus infection and those B cells that possessed surface immunoglobulin (SIg) was tested. B cells were further divided into SIg(M)- and SIg(G)-bearing cells by immunoadsorbent columns employing anti-immunoglobulin M(IgM) (mu-specific) or anti-IgG (gamma-specific) sera coated with Sephadex. The SIg(M)-bearing cells were highly susceptible. These results suggest strongly that SIg(M)-bearing B cells were the target cells for infection by IBDV.     

Sequential changes in the number of surface immunoglobulin-bearing B lymphocytes in infectious bursal disease virus-infected chickens

Variations of B lymphocytes bearing surface immunoglobulin (SIg) M [SIg(M)] and G [SIg(G)] were studied in the spleen and peripheral blood of chickens infected with infectious bursal disease virus (IBDV). The proportion of SIg-bearing B lymphocytes and SIg(M)- and SIg(G)-bearing B cells in chickens infected at one day of age decreased from 1 week postinfection (p.i.) onward and was significantly lower at 8 weeks p.i. In chickens infected at 4 weeks, the percentage of SIg-bearing B cells decreased severely during the first 2 weeks p.i. The decrease of SIg(M)-bearing B cells preceded that of SIg (G)-bearing B cells: the lowest percentage of SIg(M)-bearing B cells has observed 2 to 3 days p.i., and that of SIg(G)-bearing B cells was seen 4 days p.i. The results suggest that SIg(M)-bearing B cells are the major target for IBDV infection.     

Feeding habits of the darkfin hind Cephalopholis urodeta (Serranidae) at Iriomote Island, southern Japan

ABSTRACT: The feeding habits of the serranid fish Cephalopholis urodeta were examined on the basis of 204 adult specimens collected from coral reef areas at Iriomote Island, Ryukyu Islands, Japan. Sampling was conducted in November 1997 and February, May, and August 1998. Among the specimens, 95 (46.6%) had empty stomachs, the mean Stomach Fullness Index of the specimens overall being extremely low (0.6). Over a 1-year period, the most important prey of this species were small fishes and decapod crustaceans, the two categories together constituting 73.4% of stomach contents by weight. However, seasonal differences in basic dietary composition were apparent. Fishes were abundant in the diet in May and November, whereas the proportion of hermit crabs in the diet was higher in February compared to other months.