<Emphasis Type="Italic">Ophiostoma</Emphasis> species associated with bark beetles infesting three <Emphasis Type="Italic">Abies</Emphasis> species in Nikko,Japan

Ophiostoma species were isolated from bark beetles and Abies mariesii, A. veitchii and A. homolepis attacked by the beetles in Nikko, Tochigi, central Honshu, Japan. One to two Ophiostoma species were frequently isolated from each species of bark beetle. Ophiostoma subalpinum was the most common associate of Cryphalus montanus. Ophiostoma sp. B as well as O. subalpinum was a common fungus associated with Polygraphus proximus. Ophiostoma europhioides was isolated from Dryocoetes hectographus and D. autographus as one of the common associates. Ophiostoma sp. J and Ophiostoma sp. S were frequently isolated from D. autographus and D. striatus, respectively. These fungi seem to have specific relationships with particular bark beetles. Ophiostoma sp. B, Ophiostoma sp. J and Ophiostoma sp. S have unique morphological characteristics and appear to be new species. Five trees of A. veitchii, approximately 43 years old, were inoculated with five Ophiostoma species to assess the relative virulence of the fungi. Ophiostoma subalpinum, Ophiostoma sp. B, and O. europhioides had relatively higher virulence than the other species studied.     

Elevated level of microRNA-210 at the initiation of muscular regeneration in acetic acid-induced non-ischemic skeletal muscular injury in mice

The alteration in microRNA-210 level, a hypoxia-inducible microRNA, is not well known in non-ischemic tissue injury. In this study, we characterized the histopathological time course of acetic acid-induced skeletal muscle injury as a non-ischemic tissue injury model and investigated the expression of microRNA-210, hypoxia-inducible factor 1α, and growth factors using quantitative polymerase chain reaction analysis. After a single intramuscular dose of 3% (v/v) acetic acid to C57BL/6J mice, focal coagulative necrosis of muscle fibers was noted from 3 h after dosing and infiltration of F4/80 and Galectin-3 positive M2 macrophage was noted at 1 d after dosing. Muscular regeneration was initiated from 3 d, when M2 macrophage infiltration was most prominent, till 14 d after dosing. Hif1α and Hgf expression increased from 3 h onwards, and microRNA-210 level increased after 3 d after the treatment. However, no clear elevation in the levels of Igf1 or Vegf was observed. The infiltrative macrophages and regenerative muscle fibers were positive for hypoxia-inducible factor 1α, microRNA-210, and hepatocyte growth factor as assessed by immunohistochemistry or in situ hybridization. In this study, dominant infiltration of M2 macrophages at muscular necrosis and subsequent regeneration after a single intramuscular injection of acetic acid in mice were observed. The increase in hif1α level was observed just after the muscular injury in this non-ischemic tissue injury model, and the elevation in microRNA-210 level was noted at the initiation of tissue regeneration, indicating its effects on tissue protection and repair.     

Lipid content and fatty acid composition of muscle,liver, ovary and eggs of captive-reared and wild silver Japanese eel <Emphasis Type="Italic">Anguilla japonica</Emphasis> during artificial maturation

ABSTRACT:   Changes in lipid content and fatty acid composition of muscle, liver and ovary of captive-reared and wild silver Japanese eel Anguilla japonica were examined during artificial maturation induced by salmon pituitary homogenate (SPH) injections. Although the relative levels of n-3 and n-6 highly unsaturated fatty acids (HUFA) in liver and ovary were higher than in muscle in both captive and wild silver eels before SPH injection, these tended to decrease with maturation. The relative levels of n-6 HUFA in muscle, liver, ovary and eggs of wild silver eels were remarkably higher than those in captive eels. Therefore, we attempted to alter the ratio of n-6 HUFA in eggs by feeding eels a diet supplemented with linoleic acid-rich plant oil. Although the percentage of n-6 polyunsaturated fatty acids to total fatty acids in eggs of eels fed the supplemented diet was similar to wild silver eels, the percentage of n-6 HUFA remained remarkably lower than in wild silver eels. Hence, it appears that the supplemented diet affected the fatty acid composition of eggs, but did not result in much conversion of linoleic acid to its higher homologs in eels.     

Immunohistochemical changes in production of pituitary hormones during artificial maturation of female Japanese eel <Emphasis Type="Italic">Anguilla japonica</Emphasis>

ABSTRACT:   Specific antibodies against follicle-stimulating hormone β subunit (FSHβ), prolactin (PRL), and somatolactin (SL) of the Japanese eel Anguilla japonica were produced. These antibodies, as well as antibodies against luteinizing hormone β subunit (LHβ) and growth hormone (GH) produced previously, were used to examine changes in the production of pituitary hormones in female eels during maturation induced by salmon pituitary homogenate (SPH) injection. Immunohistochemical observations showed a decrease in FSH production after SPH injection, suggesting that SPH inhibits FSH production. In contrast, LH production increased markedly with maturation. The number of GH producing cells decreased gradually during maturation, possibly because of inhibition by exogenous GH present in the SPH and/or endogenous insulin-like growth factor-I produced by the stimulation of salmon GH. Although changes in the number of PRL producing cells with maturation were not evident, the number of SL producing cells showed a peak at the late vitellogenic stages, and thereafter decreased to the migratory nucleus stage. These results suggest that GH and SL are involved in sexual maturation in SPH injected eels, as in other fishes.     

Pathogenic diversity of soybean rust in Argentina, Brazil, and Paraguay

Phakopsora pachyrhizi, the cause of soybean rust, is an economically important pathogen of soybean in South America. Understanding the pathogenicity of indigenous fungal populations is useful for identifying resistant plant genotypes and targeting effective cultivars against certain populations. Fifty-nine rust populations from Argentina, Brazil, and Paraguay were evaluated for pathogenicity in three cropping seasons, 2007/2008–2009/2010, using 16 soybean differentials. Only two pairs of P. pachyrhizi populations displayed identical pathogenicity profiles, indicating substantial pathogenic variation in the rust populations. Comparative analysis of 59 South American and five Japanese samples revealed that pathogenic differences were not only detected within South America but also distinct between the P. pachyrhizi populations from South America and Japan. In addition, seasonal changes in rust pathogenicity were detected during the sampling period. The differentials containing resistance genes (Rpp: resistance to P. p achyrhizi) Rpp1, Rpp2, Rpp3, and Rpp4, except for Plant Introduction (PI) 587880A, displayed a resistant reaction to only 1.8–14, 24–28, 22, and 36 % of South American P. pachyrhizi populations, respectively. In contrast, PI 587880A (Rpp1), Shiranui (Rpp5), and 3 Rpp-unknown differentials (PI 587855, PI 587905, and PI 594767A) showed a resistant reaction to 78–96 % of all populations. This study demonstrated that P. pachyrhizi populations from South America vary geographically and temporally in pathogenicity and that the known Rpp genes other than Rpp1 in PI 587880A and Rpp5 have been less effective against recent pathogen populations in the countries studied.     

Effects of root exudates of Rj2Rj3- and Rj4-genotype soybeans on growth and chemotaxis of Bradyrhizobium japonicum

Almost all of the soybean cultivars (Glycine max L. Merr.) form nodules on their roots by infection with Bradyrhizobium japonicum. However, it has been observed that the soybean cultivars harboring nodulation conditioning genes, for instance Rj ₂, Rj ₃, and Rj ₄, do not form effective nodules with some strains of B. japonicum. Ishizuka et al. (1991b) classified the rhizobia isolated from field-grown soybeans into nodulation-types A, B, and C based on the compatibility with these Rj-soybean cultivars. Nodulation-type B is incompatible with Rj ₂ Rj ₃-cultivars and type C is incompatible with Rj ₄-cultivars. Nodulation-type A rhizobia are compatible with both Rj ₂ Rj ₃ - and Rj ₄-cultivars. Furthermore, the Rj-cultivars were found to prefer appropriate nodulation-type rhizobia for nodulation, that is, non-Rj-, Rj ₂ Rj ₃ -, and Rj ₄-cultivars prefer nodulation-types A, C, and B rhizobia, respectively (Ishizuka et al. 1991a). In the present study, in order to examine the mechanisms of preference of Rj-cultivars for rhizobial strains for nodulation, root exudates from Rj-cultivars were examined for their effects on the growth rate and chemotaxis of various types of B. japonicum strains.     

Detection of telomere length and oxidative stress in Chondrichthyes

Telomeres, repeating TTAGGG sequences at the ends of eukaryotic chromosomes, increase genomic stability. Telomere shortening occurs not only during DNA replication associated with cell division but also under oxidative stress, where reactive oxygen species damage DNA. Therefore, changes in telomere length can be used to evaluate chronic cost or stress responses incurred by individuals. The phylogenetically unique Chondrichthyes are among the least-studied groups of marine vertebrates. Telomere data are limited and have only been reported in a few Chondrichthyes species. In this study, we measured telomere length and quantified oxidative stress and antioxidant power in 17 Chondrichthyes species whose telomere length has not been measured before. The presence of telomere sequences?>?30 bp and lower values of oxidative stress were confirmed in most species. Average telomere length was not correlated with oxidative stress and antioxidant power in 15 species for which both measurements were available. It would be desirable in the future to elucidate the nature of telomeres in Chondrichthyes, and their direct relationship with reactive oxygen species.

     

Serum cystatin C concentration can be used to evaluate glomerular filtration rate in small dogs

Serum cystatin C levels (CysC) are used in human medicine to document progressive kidney failure. Although CysC are not thought to be useful for the diagnosis of kidney dysfunction in dogs, there has been no specific consideration of body weight as a confounding issue. The aim of this study was to assess that the utility of CysC for the diagnosis of decreased glomerular filtration rate (GFR) in smaller vs. larger dogs. In clinically healthy dogs, serum creatinine (Cre) and CysC correlate directly with body weight; we found that dogs weighing <20 kg had significantly lower CysC than those weighing ≥20 kg (0.27 ± 0.07 vs. 0.34 ± 0.05 mg/l, respectively, P<0.001). In dogs weighing <20 kg, CysC had superior diagnostic accuracy for the detection of mildly decreased plasma iohexol clearance (PCio) (<1.8 ml/min/kg) compared with Cre (sensitivity 100% vs. 80.9% and specificity 100% vs. 85.7%); this was not true for dogs weighing ≥20 kg. Additionally, using a cut-off PCio of <1.8 ml/min/kg, the area under receiver-operating characteristics curve (AUC) of CysC was significantly higher than that of Cre in dogs weighing <20 kg (P<0.05); this was not true for dogs weighing ≥20 kg (P=0.695). In conclusion, CysC is a useful marker for the detection of a mild decreasing GFR compared with Cre in dogs weighing <20 kg.