Detection and differentiation of Leptospira spp. serovars in bovine semen by polymerase chain reaction and restriction fragment length polymorphism

In view of the importance of venereal transmission of bovine leptospirosis, the objective of the present study was to apply the polymerase chain reaction (PCR) to 26 serovars of Leptospira interrogans, L. borgpetersenii, L. santarosai, L. noguchii and L. biflexa, to determine the detection threshold in semen samples and to evaluate the possibility of differentiation among serovars using 19 restriction endonucleases. The results showed that all serovars were amplified and the detection threshold in semen samples of a bull was 100 bacteria/ml. Using endonucleases we could classify the 26 serovars into eight groups. The present results show that PCR is a method of great potential for the detection of Leptospira spp. at bovine artificial insemination centers.     

Does future climate change facilitate expansion of evergreen broad-leaved tree species in the human-disturbed landscape of the Korean Peninsula? Implication for monitoring design of the impact assessment

To quantitatively assess future change of evergreen broad-leaved tree species’ distributions in human-disturbed landscapes of the Korean Peninsula under climate change, potential habitats (PHs) were projected for four important evergreen broad-leaved tree species (Quercus acuta, Castanopsis sieboldii, Machilus thunbergii, and Neolitsea sericea) by species distribution models (SDMs). The distribution data (presence/absence) of the target species in Korea and Japan were used as response variables for SDMs, and climatic data were used as explanatory variables. Three general circulation models under A2 emission scenarios were used as future climate scenarios for the years 2070–2099. Potential habitats masked by land-use data (PHLUs) were projected to assess the impact of anthropogenic activities. Highly accurate SDMs were obtained for all the target species. The current PHs were decreased to 21–35 % by the anthropogenic activities. Future PHLUs for all the target species were projected to increase by 2.0–18.5 times of current PHLUs. These results suggest that all the target species are applicable as indicator species for monitoring in the Korean Peninsula, even if anthropogenic effects are incorporated. Variation of the increasing rate was caused by the differences in the response to temperature changes. M. thunbergii responded sensitively to the increase of minimum temperature of coldest month and had a largest increase in PHLUs under future climate. Therefore, M. thunbergii is considered to be most appropriate species for monitoring the changes of horizontal distributions above all focal evergreen broad-leaved tree species.     

Treatment with an aromatase inhibitor induces complete sex change in the protogynous honeycomb grouper (Epinephelus merra)

To study the mechanism of protogynous sex change in honeycomb grouper, the wild fish of both sexes and transitionals were collected for one year, and changes in gonadal structures and serum levels of sex hormones in each individual were examined. The onset of sex change was associated with low serum estradiol - 17β (E2) levels. In order to clarify whether E2 deprivation causes sex change, maturing females were implanted with the non-steroidal aromatase inhibitor (Fadrozole, AI). AI caused complete sex change from female to functional males in two and half months. The present results suggest that E2 is an important endogenous factor which regulates protogynous sex change in the honeycomb grouper.     

Effects of complete submergence on seedling growth and survival of five riparian tree species in the warm-temperate regions of Japan

To reveal the relationship between tolerance to submergence and the distribution ranges of riparian tree species in the floodplains of the warm-temperate regions in Japan, we assessed the response and tolerance of current-year seedlings of two Salix and three Ulmaceae species to submergence treatments for 1, 2, 4, and 8 weeks. We investigated shoot elongation, number of leaves, and survival rate of seedlings during the experiment, and biomass allocation was determined at the end of the experiment. Shoot elongation and leaf production of seedlings were suppressed in all the species during the submergence treatments. However, the seedlings of Salix chaenomeloides and S. pierotii elongated shoots rapidly and produced leaves after the treatments. All the underground biomass in these two species was larger than aboveground biomass. These results are considered as typical responses of flood-tolerant species. In contrast, the underground biomass of Ulmaceae seedlings (Celtis sinensis var. japonica, Aphananthe aspera, and Ulmus parvifolia) decreased more rapidly than aboveground biomass during prolonged submergence. Furthermore, A. aspera seedlings also showed suppression of shoot elongation and leaf production after the treatments. Our results indicate that the three Ulmaceae species are less tolerant to submergence than the two Salix species. In conclusion, we suggest that submergence stress is one of the important factors determining the distribution of tree species in the floodplains of lowlands in the warm-temperate regions of Japan.     

A multiplex PCR for the detection of Brucella spp. and Leptospira spp. DNA from aborted bovine fetuses

Bovine brucellosis and leptospirosis are important causes of bovine abortion around the world. Both diseases can be serologically diagnosed, but many factors may cause false positive and negative results. Direct methods based on bacteriological isolation are usually employed, but they are difficult, time consuming and dangerous. Monoplex polymerase chain reaction (PCR) have been successfully described for the detection of Brucella spp. and Leptospira spp. Aiming at improvement in the direct diagnosis, a multiplex PCR (mPCR) for the detection of these agents in aborted bovine fetuses is described. The detection threshold of the mPCR was evaluated in experimentally contaminated bovine clinical samples using a conventional proteinase K/SDS or a boiling-based extraction protocols. The mPCR was applied to two groups of clinical samples: 63 episodes of bovine abortion and eight hamsters experimentally infected with Leptospira interrogans serovar pomona. Adopting microbiological isolation as reference, the test showed a sensitivity of 100% in both groups of clinical samples. Seven samples collected from bovine fetuses were Brucella spp. culture negative but showed positive results in mPCR. Regarding Leptospira spp. detection, similar results were observed in three bovine clinical samples. All hamsters infected with Leptospira were positive in both microbiological culture and mPCR. The boiling extraction protocol showed better results in some clinical samples, probably by the removal of PCR inhibitors by heat treatment. The high sensitivity, simplicity and the possibility of detection of both bacteria in a single tube reaction support the use of the mPCR described in the routine diagnosis.     

Polycitorols A and B,New Tricyclic Alkaloids from an Ascidian

Two new tricyclic alkaloids, polycitorols A (1) and B (2) have been isolated along with the known lepadiformine (3) from a marine ascidian of the family Polycitoridae. The structures of the new compounds were elucidated by analysis of NMR data and comparison with those of 3 and other related compounds [1–5]. Compounds 1 and 2 are closely related to cylindricines A and B, lacking C-4 oxygenation found in cylindricines and having a butyl instead of a hexyl appendage. NOE experiments on compounds 1 and 2 suggested the A/B ring fusion to be cis.     

Pigs as an experimental model for systemic Mycobacterium avium infectious disease

Mycobacterium avium complex (MAC) is an opportunistic pathogen in AIDS patients and pigs, and causes dissemination through primary intestinal lesions. However, its pathogenesis is not well understood. In this article, we hypothesize that pigs can provide a suitable experimental model of disseminated MAC disease. We compared the initial route of infection, the characteristics of the pathogenic strains, the immunological status of the hosts, and the histological characteristics. The route of infection and infective strains are similar in AIDS patients and pigs. Pigs can respond to infection by the formation of systemic epithelioid granuloma with sufficient cell-mediated immunity. However, there are differences in immunological status and histological features between AIDS patients and pigs. Therefore, pigs might be used as an appropriate animal model because of their good cell mediated immunity triggered by systemic mycobacterial infection. In conclusion, MAC infections in AIDS patients and pigs show similarities in terms of the initial route of infection and the genetic characteristics of the pathogenic strains.     

What controls the distribution of the Japanese endemic hemlock, Tsuga diversifolia? Footprint of climate in the glacial period on current habitat occupancy

Plant distributions are thought to be controlled by climate at large scales, and by non-climatic factors including soil conditions, topography and biotic interactions at smaller scales. However, not all plant distributions are explained by the current environment. Lags between current plant distributions and suitable environment for them are suggested to exist, which is often called empty habitat. To identify the existence and cause of lags between current climate and the distribution of Tsuga diversifolia, climatic conditions for the species distribution were clarified and potential habitats under current and the last glacial maximum (LGM; 21 ka) climates have been projected. The relationships between T. diversifolia distribution and climatic variables were explored using a classification tree model and a generalized additive model based on high-resolution (ca. 1 km) climatic data and a nationwide distribution database. The models were highly accurate. We revealed that T. diversifolia requires high summer precipitation even in humid Japanese environments. Areas with cool and wet summers were classified as potential habitat. Empty habitat for the focal species was identified in Hokkaido. Meanwhile, no potential habitat was projected in Hokkaido under the LGM. Additional experiments that varied temperature and summer precipitation during the LGM showed that the potential habitat was projected in Hokkaido irrespective of temperature decrease if summer precipitation increased nearly equal to the current climate. These results suggest that T. diversifolia vanished from Hokkaido, where fossil evidence indicated its occurrence until the late Neogene, during the glacial periods of the Pleistocene because of increased summer dryness.     

Climatic controls of a keystone understory species, <Emphasis Type="Italic">Sasamorpha borealis</Emphasis>, and an impact assessment of climate change in Japan

Introduction   

The aims of this study were to identify the climatic conditions controlling the distribution of Sasamorpha borealis and to assess the impact of climate change on the species in Japan.