Identification of genes for two major sialoglycoproteins, glycophorin A and glycophorin C in canine red cell membranes

Glycophorins are the major sialoglycoproteins in red blood cell membranes, possessing various physiological and pathological roles. We examined membrane glycoproteins in canine red cells and cloned cDNAs for two major glycophorins, glycophorins A (GPA) and C (GPC) from bone marrow cells. Periodic acid-Schiff staining and immunoblotting analyses showed that canine red cell membranes contained several glycoproteins immunoreactive to an anti-bovine GPC antibody, whereas the most abundant sialoglycoproteins, the candidates for GPA, did not react with an anti-human GPA antibody. The amino acid sequences of the extracellular domains of GPA and GPC had no significant homology to those from other mammalian species, including humans, and had O-linked and/or N-linked glycosylation sites. On the other hand, the C-terminal cytoplasmic domain and/or the transmembrane helices of GPA and GPC were conserved among species, indicating some functional significance of those regions in red cell membranes that include dimerization of GPA in the membrane-spanning region, and association of GPC with membrane skeletal proteins through binding with protein 4.1 and p55 in the cytoplasmic domain. These findings provide insights for clinical studies to evaluate the involvement of GPA and GPC in the pathogenesis of red cell diseases.     

Mediastinal lymphoma with complete atrioventricular block in a horse

A 15-year-old, neutered-male pony presented with a history of weight loss during 4 months. Clinical evaluation revealed severe bradycardia and complete atrioventricular block. At necropsy, a lobulated mass in the anterior mediastinum and moderate enlargement of the superficial cervical lymph nodes were observed. The vagus nerve and the brachiocephalic trunk were embedded in this anterior mediastinal tumor. Histologically, the mass was composed of sheets of neoplastic lymphoid cells expressing CD3, with a low mitotic rate. To the best of our knowledge, this is the first reported case of mediastinal lymphoma associated with complete atrioventricular block in horses.     

Effects of diet and temperature on post‐settlement growth and survival of the short‐spined sea urchin Strongylocentrotus intermedius

Effects of diet and temperature on post‐settlement growth and survival of a sea urchin Strongylocentrotus intermedius, which fed on one of six mono‐cultured benthic diatoms, gametophytes of a brown alga Undaria pinnatifida, a green alga Ulvella lens plus mixed benthic diatoms, or no food at 6, 9, 12 and 15°C, were examined. Digestion efficiency (DE), ingestion rate (IR), excretion rate (ER) and digested cell content index (DCCI) of each diatom species were measured. Growth rates largely differed among the dietary treatments from 7 days post‐settlement. Sea urchins fed on a diatom Cocconeis sublittoralis showed considerably higher growth (7.85‐34.67 μm day^?1) than those fed on the other diets and high survival rates (100%). DCCI was also highest in C. sublittoralis. These results suggest that the quantity of diatom cell contents digested is an important factor affecting growth and survival of the sea urchins. Growth rates of sea urchins were higher in higher water temperatures, and significant differences in growth rate were observed between 6‐9 and 12‐15°C. ERs of C. sublittoralis were generally higher at higher temperatures, but DEs did not differ among the temperature treatments. Variations in growth rate among different water temperature appear to be caused by different food intakes of the urchins.     

An alternative of soil scarification treatment for forest restoration: effects of soil replacement

We examined an alternative natural regeneration practice with a scarification treatment, in which removed soil is replaced on the scarified area, in northern Japan. The effect of the soil replacement on tree establishment was quite obvious; the basal area of trees, composed mostly of Betula ermanii, in the soil-replaced site was about 150-fold greater than that of the normally treated site. The greater growth rates together with higher density, both of which seemed to be enhanced by improved (i.e., deeper, tender, and nutrient-rich) soil properties, produced the marked difference to the normally treated site. The expected enhancement of species diversity owing to utilizing buried seeds in the replaced soil was not found. The current study revealed that the soil replacement could substantially improve forest restoration management with emphasis on biomass production for large nonwooded sites.     

The distribution of normal and male-sterile cytoplasms in Chinese sugar-beet germplasm

Forty-two Chinese sugar-beet breeding lines were evaluated for the presence of normal and male-sterile (Owen) cytoplasms using polymorphisms in the chloroplast petG-psbE region as well as in the mitochondrial minisatellite loci. The polymorphisms detected allowed the distinction of three cytoplasm types over the whole sample, one being associated with Owen cytoplasm, a second with the maintainer inbred ‘TK-81mm-O’-type cytoplasm (termed normal-1 cytoplasm) and a third with another maintainer inbred ‘NK-310mm-O’-type cytoplasm (normal-2 cytoplasm). Western blot analysis was carried out to confirm that expression of the male-sterility-associated protein (preSATP6) occurred in plants with Owen cytoplasm but not in plants with either normal-1 or normal-2 cytoplasm. Of the 42 breeding lines examined, 14 had exclusively normal (normal-1 and/or normal-2) cytoplasm and 11 had only Owen cytoplasm. The remaining 17 lines possessed both normal and Owen cytoplasms, and noticeably, some of these 17 lines have been expected to become the source of superior maintainer lines. The results thus show that molecular identification of the cytoplasm is required to avoid wasting resources on account of attempting to develop the maintainer genotype from plants with Owen cytoplasm.     

Multiple cohorts of juvenile jack mackerel Trachurus japonicus in waters along the Tsushima Warm Current

The jack mackerel, Trachurus japonicus, has a prolonged spawning season and widely spread spawning grounds. The population in the coastal waters of Japan seems to be composed of several cohorts spawned seasonally from different waters. To understand its population structure along the Tsushima Warm Current, we analysed hatchdates and growth histories of fish from Kunda Bay, the southern, central and northern East China Sea (ECS), the southern Sea of Japan, and Maizuru Bay. Seven cohorts were detected from fish collected between June 2005 and June 2006 in Kunda Bay. Comparing hatchdate distributions and growth trajectories of the seven cohorts with those of the other five regional samples, we did not find that cohorts collected in Kunda Bay originated in the southern ECS. Therefore, these coastal waters of Japan appear to be significant spawning grounds for juvenile jack mackerel.     

Effects of tillage and irrigation on the occurrence and establishment of native wetland plant species in fallow paddy fields

Traditional weed management, such as tillage and irrigation, has led to an enhanced maintenance of wetland plant species in fallow paddy fields. Recent herbicide usage and improvements in irrigation and drainage systems however have caused habitat loss of these species, especially in fields on open lowlands. We conducted experiments in three fallow paddy fields situated on the alluvial Echigo Plain in central Japan with an aim to restore the habitat of native wetland plant species. The three experimental fields were managed under different irrigation regimes, (1) perennially flooded with water, (2) intermittent irrigation, and (3) temporary irrigation. Half the area of each experimental field was tilled before irrigation. Detrended correspondence analysis revealed obvious floristic differences between experimental and control fields with no irrigation. The proportion of wetland plant species in the experimental fields increased corresponding to the irrigation period, ranging 60–86%, and was relatively greater than that in control fields. In the experimental fields, differences in both tillage and irrigation affected the occurrence of plant species. Tillage restricted the occurrence of many non-wetland plant species, and had a positive effect on the establishment of several annual wetland plant species. In addition, a longer duration of irrigation is not necessarily suitable for the occurrence of all wetland plant species. We concluded that fallow paddy fields provide a possible habitat for the restoration of native wetland plant species through appropriate tillage and irrigation.     

Feeding of the short-spined sea urchin <Emphasis Type="Italic">Strongylocentrotus intermedius</Emphasis> on macroalgae and benthic animals

To examine the feeding ecology of the sea urchin Strongylocentrotus intermedius, two types of macroalgal diet (kelp Saccharina longissima and red alga Ptilota filicina) and four types of benthic animal diet [barnacle Balanus glandula, limpet Lottia cassis, free-living Perinereis aibuhitensis and P. aibuhitensis attached to a stainless steel wire (wired polychaete)], were separately or simultaneously provided for urchins of 5- to 60-mm test diameter (TD). Sea urchins of even 3-mm TD could graze the kelp, and began to graze the red alga, the wired polychaete and limpet by 5-mm TD, the barnacle by 8-mm TD and the free-living polychaete by 15-mm TD, respectively. These results suggest that the variety of macroalgae and benthic animals which the urchin can graze increases with the ontogeny of their feeding organs, motility and ability to catch animals. Both juvenile and adult sea urchins preferred to eat the polychaete as well as the kelp fronds. Feed conversion efficiency and daily growth rate of the small sea urchins fed benthic animals like the polychaete were higher than those fed macroalgae. The sea urchins are likely to grow better when feeding on animals than on macroalgae, even in habitats where they can access adequate quantities of kelp.     

Identification of the epsilon-(gamma-glutamyl)lysine cross-linking sites in alpha-lactalbumin polymerized by mammalian and microbial transglutaminases

To investigate the site specificity of two transglutaminases (TGases), that is, the enzymes from guinea pig liver (GTGase) and Streptoverticillium (MTGase), the acyl acceptor and donor sites in alpha-lactalbumin were determined. Alpha-lactalbumin was cross-linked in the presence of dithiothreitol by GTGase and MTGase for 15 and 30 min, respectively. Cross-linked alpha-lactalbumins by GTGase and MTGase were digested with lysylendopeptidase followed by the separation of the resulting peptides using reverse-phase HPLC. By the sequence analysis of the peptide fragments containing two N termini, which indicates the presence of cross-linked peptide, the lysine residues targeted by TGases were identified as follows: for GTGase, Lys16, Lys93, and Lys122; for MTGase, Lys5. These peptide fragments were further digested by V8 protease. Separation and sequence analyses of the resultant peptides were performed to identify glutamine residue involved in cross-linking. It was found that Gln54 was cross-linked to lysine residues by GTGase and MTGase in common. It is suggested that the difference in the numbers of lysine residues targeted by GTGase and MTGase may be responsible for the difference in the polymerization process of alpha-lactalbumin between GTGase- and MTGase-catalyzed systems.