Detection of antibodies to leptospirosis in experimentally infected dogs using the microcapsule agglutination test

Six puppies were infected with a virulent strain of Leptospira interrogans serovar icterohaemorrhagiae and another five animals with a virulent strain of Leptospira interrogans serovar canicola, respectively. Antibodies were examined at 3, 5, 7, 11 and 14 days after infection, using the microcapsule agglutination test (MCAT) and the conventional microscopic agglutination test (MAT). Compared with the MAT, the MCAT detected early specific IgM antibody with high sensitivity. The MCAT titres reached a peak at the 7th day after infection and declined gradually after the 11th day, while the MAT titres increased up to the 14th day.     

Distribution of leptospirosis among stray dogs in the Okinawa Islands, Japan: comparison of the microcapsule and microscopic agglutination tests

Three hundred and thirty-eight sera collected from stray dogs in the Okinawa islands were examined for antibodies against Leptospira interrogans using the microscopic agglutination test (MAT) and the one-point microcapsule agglutination test (MCAT). Seventy-eight sera (23%) showed a positive reaction to at least one of the six serovar antigens, and 69 of these reacted with serovar canicola by microcapsule agglutination test. The mixed microcapsule agglutination test detected 68 of the microscopic agglutination test-positive sera, and the 10 remaining were negative by microcapsule agglutination test. On the other hand, a single microcapsule agglutination test which was sensitized with serovar canicola detected 77 of the microscopic agglutination test-positive sera and the remaining one was microcapsule agglutination test-negative.     

Ionic liquids as formaldehyde-free wood adhesives

Several ionic liquids promote depolymerization of wood components, i.e., polysaccharides and lignin, into low molecular weight compounds, some of which further re-polymerize into resin-like compounds. In this study, the depolymerization/re-polymerization of wood components in ionic liquids was applied to preparation of plywoods from Japanese cedar (Cryptomeria japonica) veneers by employing ionic liquids as adhesives. The adhesive solution was prepared by mixing an ionic liquid (pyridine hydrochloride ([Py][Cl]), imidazole hydrochloride ([IM][Cl]), or 1-ethylpyridinium chloride ([EtPy][Cl])) with water and d-glucose in various weight ratios. Tensile shear test of the three-ply plywoods prepared from the veneers and the adhesive solution through hot-pressing indicated that the plywood bonded with the [IM][Cl]-based solution ([IM][Cl]/water/glucose ratio: 9/3/2) exhibited the highest strength. Scanning electron microscope observation on the plywoods suggested that the ionic liquids softened the cell walls of the probably plywood through the depolymerization/re-polymerization reactions and the cell walls were compressed during the hot-pressing process. Entwining of the compressed cell walls and van der Waals force enhanced by the compression were considered to be origins of the adhesion of the veneers.     

Biogeography of pelagic food webs in the North Pacific

The tufted puffin (Fratercula cirrhata) is a generalist seabird that breeds throughout the North Pacific and eats more than 75 different prey species. Using puffins as samplers, we characterized the geographic variability in pelagic food webs across the subarctic North Pacific from the composition of ~10,000 tufted puffin meals (~56,000 prey items) collected at 35 colonies in the Gulf of Alaska (GoA) and Aleutian Archipelago. Cluster analysis of diet species composition suggested three distinct forage fish communities: (i) in the northern GoA, multiple age‐classes of coastal and shelf residents such as capelin, sand lance and herring dominated the food web, (ii) in the western GoA to eastern Aleutians, the shelf community was dominated by transient age‐0 walleye pollock, and (iii) in the western Aleutians, shelf‐edge and mesopelagic forage species such as squid, lanternfish, and Atka mackerel were prevalent. Geographic patterns of abundance of capelin and sand lance in tufted puffin diets were corroborated by independent research fisheries and diets of piscivorous fish, indicating that puffin diets reflect the local abundance of forage species, not just selection of favored species. Generalized additive models showed that habitat characteristics predict, in a non‐linear fashion, forage species distribution and abundance across two large marine ecosystems. We conclude that major biogeographic patterns in forage fish distribution follow gradients in key habitat features, and puffin diets reflect those patterns.     

Glycophorin A-knockout mice, which lost sialoglycoproteins from the red blood cell membrane, are resistant to lethal infection of Babesia rodhaini

Recent in vitro-based studies using several Babesia spp. have suggested that sialic acids and/or sialoglycoproteins on host red blood cells (RBCs) play an important role in their invasion of RBCs. In the present study, we analyzed the RBC characteristics of glycophorin A (GPA)-knockout mice and studied their in vivo susceptibility to lethal infection of Babesia rodhaini for the first time. In immunoblot and lectin blot analyses, glycoproteins containing O-linked oligosaccharides terminated with alpha2-3-linked sialic acids disappeared from the RBCs of GPA homozygous ((-/-)) mice. Flow cytometric analysis showed a remarkable reduction of Maackia amurensis lectin II binding to the surface of GPA(-/-) RBCs relative to control RBCs, indicating an appreciable loss of alpha2-3-linked sialic acids on the RBC surface of GPA(-/-) mice. Importantly, while B. rodhaini caused lethal infection in wild-type mice, the infected GPA(-/-) mice showed inhibition of parasite growth and eventually survived. These results indicate that RBC sialoglycoproteins lost in GPA(-/-) mice are involved in the in vivo growth of B. rodhaini, probably functioning as essential molecule(s) for the parasite invasion of host RBCs in the blood circulation.     

Responses of Crops to Soil Salinization in South Baja California,Mexico

Soil salinization has become a serious problem all over the world. In this study, the influence of salinity of irrigation water and soil on plant nutrition and physiological disorders were investigated. The study was conducted in three agricultural fields in South Baja California, Mexico where saline stress of crops by soil salinization has become a serious problem under the arid climate.

There was a significant correlation (P < 0.05) between sodium (Na) concentration and electrical conductivity (EC) of the water. The soil pH was extremely high in all areas, and the Na concentration was higher than that of other elements. In spite of the salinized water and soil, vegetables did not show symptoms of nutritional disorders. Unlike the vegetables, fruit leaves showed symptoms of nutritional disorders. There was not a correlation between the concentration ratio (CR) of elements of the leaves, which showed symptoms to healthy leaves in a same tree, and the visible symptoms of the nutritional disorder.     

Puffins reveal contrasting relationships between forage fish and ocean climate in the North Pacific

Long‐term studies of predator food habits (i.e., ‘predator‐based sampling’) are useful for identifying patterns of spatial and temporal variability of forage nekton in marine ecosystems. We investigated temporal changes in forage fish availability and relationships to ocean climate by analyzing diet composition of three puffin species (horned puffin Fratercula corniculata, tufted puffin Fratercula cirrhata, and rhinoceros auklet Cerorhinca monocerata) from five sites in the North Pacific from 1978–2012. Dominant forage species included squids and hexagrammids in the western Aleutians, gadids and Pacific sand lance (Ammodytes personatus) in the eastern Aleutians and western Gulf of Alaska (GoA), and sand lance and capelin (Mallotus villosus) in the northern and eastern GoA. Interannual fluctuations in forage availability dominated variability in the western Aleutians, whereas lower‐frequency shifts in forage fish availability dominated elsewhere. We produced regional multivariate indicators of sand lance, capelin, and age‐0 gadid availability by combining data across species and sites using Principal Component Analysis, and related these indices to environmental factors including sea level pressure (SPL), winds, and sea surface temperature (SST). There was coherence in the availability of sand lance and capelin across the study area. Sand lance availability increased linearly with environmental conditions leading to warmer ocean temperatures, whereas capelin availability increased in a non‐linear manner when environmental changes led to lower ocean temperatures. Long‐term studies of puffin diet composition appear to be a promising tool for understanding the availability of these difficult‐to‐survey forage nekton in remote regions of the North Pacific.     

Effects of ocean climate on the length and condition of forage fish in the Gulf of Alaska

Climatic drivers of the size and body condition of forage fish in the North Pacific are poorly known. We hypothesized that length and condition of forage fish in the Gulf of Alaska (GoA) vary in relation to ocean temperature on multiple scales. To test this hypothesis, we analyzed morphometric data for capelin (Mallotus catervarius) and Pacific sand lance (PSL; Ammodytes personatus) sampled by a seabird (Cerorhinca monocerata) in two regions of the GoA, 1993–2016. Based on previous studies, we predicted that capelin length and body condition (Fulton's K) would be negatively related to the Pacific Decadal Oscillation (PDO) and sea surface temperature (SST), whereas PSL length and condition would be positively related. Interannual variation in length and body condition was evaluated relative to seasonal values of ocean climate using regression. Forage fish length and condition varied interannually, between sampling regions, and were dependent on the size/age class of the fish sampled. As predicted, length and body condition of capelin (mostly age 1+) were negatively related to the PDO and SST. Relationships with ocean climate for PSL varied by size/age class: positive for putative age‐0 fish and negative for putative age‐1+ fish. We conclude that our hypothesis was supported for capelin and partially supported for PSL. This study demonstrates that ocean climate determines key morphometric characteristics of forage fish that may relate to interannual variation in the energetic value of prey, and provides an example of how seabirds can be used to obtain specimens for evaluations of potential prey quality.     

Enhancement of phagocytic and chemokinetic activities of rainbow trout head kidney cells by C-reactive protein

OBJECTIVE: To investigate immunostimulating activity of purified rainbow trout (Oncorhynchus mykiss) C-reactive protein (CRP) on trout phagocytic cells. ANIMALS: 20 rainbow trout and 2 rabbits. PROCEDURE: The effect of CRP on phagocytic activity of head kidney (HK) cells was examined by use of a phagocytosis assay with plastic particles. The enhancing effect of CRP on migration activity of HK cells was examined by use of the blind well assay. RESULTS: Glass-adherent cells from clinically normal trout had increased dose-dependent phagocytic activity against plastic particles when cells were incubated in the presence of CRP. Pretreatment of particles with CRP also enhanced phagocytic activity of the cells, indicating an opsonic effect of CRP. Rabbit anti-trout CRP serum suppressed the enhancing activity of CRP. The HK cells had significant dose-dependent chemokinetic activity against CRP that was not inhibited by anti-CRP serum, indicating that a CRP-antibody complex also could be chemokinetic. CONCLUSIONS: Rainbow trout CRP has immunostimulating activity for HK cells, resulting in enhanced phagocytic and chemokinetic activities.