Detection of DNA of 'Candidatus Mycoplasma haemominutum' and Spiroplasma sp. in unfed ticks collected from vegetation in Japan

DNA fragments of 'Candidatus Mycoplasma haemominutum', a feline heamobartonella pathogen, were detected from unfed Ixodes ovatus collected from vegetation in Hokkaido, Fukushima and Yamaguchi Prefectures, and unfed Haemaphysalis flava in Yamaguchi Prefecture. This finding suggests that ixodid tick is a possible vector of 'C. Mycoplasma haemominutum'. Spiroplasma DNA was also detected from unfed I. ovatus in Hokkaido, Fukushima and Yamaguchi Prefectures. The analysis of nucleotides sequence suggested that this Spiroplasma was distinct from registered species.     

Artificial insemination with frozen epididymal sperm in cats

Artificial insemination with frozen cauda epididymal sperm was performed in cats. Sperm were transmigrated from the epididymides in 10 male cats. The mean sperm motility and viability were 67% and 82.5%, respectively, and 11.6 x 10(7) sperm were recovered. The mean sperm motility after thawing was 24.0%. Eleven female cats received unilateral intrauterine insemination of 5 x 10(7) sperm, and the conception rate was 27.3% (3/11). This was the first case of conception obtained with frozen epididymal sperm in cats.     

A binding protein for fungal signal molecules in the cell wall of Pisum sativum

In the plant cell wall of Pisum sativum seedlings, we found an NTPase (E.C. 3.6.1.5.) with ATP-hydrolyzing activity that was regulated by an elicitor and suppressors of defense from pea pathogen Mycosphaerella pinodes. The ATPase-rich fraction was purified from pea cell walls by NaCl solubilization, ammonium sulfate precipitation, and chromatography with an ATP-conjugated agarose column and an anion-exchange column. The specific activity of the final ATPase-rich fraction increased 600-fold over that of the initial NaCl-solubilized fraction. The purified ATPase-rich fraction also had peroxidase activity and generated superoxide, both of which were regulated by the M. pinodes elicitor and suppressor (supprescins). Active staining and Western blot analysis also showed that the ATPase was copurified along with peroxidases. In this fraction, a biotinylated elicitor and the supprescins were bound primarily and specifically to ca. 55-kDa protein (CWP-55) with an N-terminal amino acid sequence of QEEISSYAVVFDA. The cDNA clone of CWP-55 contained five ACR domains, which are conserved in the apyrases (NTPases), and the protein is identical to a pea NTPase cDNA (GenBank accession AB071369). Based on these results, we discuss a role for the plant cell wall in recognizing exogenous signal molecules.     

An Efficient Inoculation Method for Colonization of Chinese Cabbage Seedlings by the Root Endophytic Fungus Heteroconium chaetospira

To develop an efficient method to inoculate Chinese cabbage seedlings with the root endophytic fungus Heteroconium chaetospira, an appropriate nursery soil and glucose concentration for the nutrient medium for fungal colonization were determined. A grid-sheet method was established for estimating the degree of colonization of entire roots by the fungus. The fungus colonized at high frequencies when peat moss was used as the rooting medium. Colonization was highest (75%) when peat moss was amended with 0.1% glucose. Under these conditions, fungal hyphae developed intracellularly in root cortical cells. In contrast, under high glucose conditions, fungal colonization was restricted mostly to intercellular regions of epidermal or cortical root tissues. Here, hyphae formed inter- or intracellular microsclerotia. Received 19 August 2002/ Accepted in revised form 5 December 2002     

Interannual variation of the diet shifts and their effects on the fatness and growth of age‐0 Pacific bluefin tuna (Thunnus orientalis) off the southwestern Pacific coast of Japan

We investigated the effect of feeding habits on the fatness (length–weight relationship (LW)) and otolith growth of age‐0 Pacific bluefin tuna (PBF) (fork length (FL) of 15.0–29.9 cm) collected off the southwestern Pacific coast of Japan from July to August during 2010–2015. The feeding rate on Clupeiformes (FRc) was substantially influenced by the path of the Kuroshio Current during early summer. We suggest that the following patterns occurred in the feeding habits of PBF. In 2012 and 2014, the short distance from the coast to the Kuroshio provided high overlap between PBF and Clupeiformes and increased the opportunity for feeding, and this pattern likely caused the observed diet shift from Crustacea to Clupeiformes by smaller PBF in the studied years than those in other years. In 2011 and 2015, the encounter probability for Clupeiformes might have been low due to the long distance to the Kuroshio Current, which led PBF to actively consume non‐Clupeiformes Teleostei. In contrast, in August 2010 and 2015, PBF did not encounter Clupeiformes or other Teleostei and may have been forced to feed on a large number of Crustacea; this effect was likely due to high water temperatures. Despite the interannual fluctuation in the timing of the diet shift and the feeding intensity (FI), these factors did not contribute to growth in length; rather, they contributed to fatness. Considering size‐dependent mortality in the larval stage, these results suggest that only fast‐growing individuals survive, even if the feeding conditions drastically change.     

Bioremediation of organically enriched sediment deposited below fish farms with artificially mass-cultured colonies of a deposit-feeding polychaete <Emphasis Type="Italic">Capitella</Emphasis> sp. I

ABSTRACT:   For bioremediation of organically enriched sediment deposited below fish farms, the extremely high potential for population growth of a deposit-feeding polychaete, Capitella sp. I, in the organically enriched sediment, and the effect on decomposition of organic matter in the sediment, were examined. A mass-culturing technique was conducted for this species. Bioremediation experiments were conducted on the organically enriched sediment in a fish farm in Kusuura Bay, Japan in 2003–2006. Approximately 1.7 million individuals of the worms were placed on the sediment below one net pen in December 2003, 9.3 million individuals in November 2004, and 2.2 million individuals in November 2005. After the worms were spread on the sediment, they rapidly increased in number and reached the highest densities of approximately 134 000 inds/m² in February 2004, 527 000 inds/m² in March 2005 and 103 000 inds/m² in January 2006. In the process of rapid population growth, the decomposition of the organic matter of the sediment was enhanced markedly. Our results demonstrate that the promotion of population growth by spreading cultured colonies of Capitella can enhance the decomposition rate of organic matter markedly in organically enriched sediment below fish farms. This method is promising for minimization of the negative effects of fish farms.     

日本对虾杆状核病毒性传染病诊断技术

本文提出了分别用暗视野显微技术和透射电子显微技术快速确诊日本对虾杆状核病毒性传染病的方法。在暗视野显微镜下观察到的血淋巴中的病毒粒子大小约为0.5μm;胃表层上皮被病毒感染的细胞核明显地呈白色均质小体,直径10～15μm,球形或椭圆形,坏死细胞被囊化为棕色小块(约20～50μm)。病虾血淋巴和胃经负染制样在透射电子显微镜下观察病毒颗粒大小为400×150nm;核衣壳大小为390×85nm。     

Control of dissolved oxygen levels of water in net pens for fish farming by a microscopic bubble generating system

ABSTRACT:   A microscopic bubble generating system (MBGS) has been developed to control dissolved oxygen (DO) levels suitable for fish farming. The MBGS has been tested to confirm its capability in net pens. Water conditions in a fish farm were monitored every two hours from June to October 2004 by setting an online vertical profiling system (OVPS) close to the net pen. DO in the net pen water decreased to physiologically stressful levels for the fish during the night (4.84–5.51 mg/L), while the DO was kept in saturated conditions during the day, due to oxygen supply from phytoplankton. The MBGS was operated from the evening to the morning of the next day for 16 h, to successfully create DO-saturated conditions in the net pen water at night. By using microscopic bubbles during the warm seasons, DO levels in the net pen water could be improved to a level suitable for fish farming. However, the low DO levels (<5.0 mg/L) of the bottom water occasionally extended to the net pen layers, despite the supply of microscopic bubbles to the water. To maintain the DO of the net pen water at levels suitable for fish farming, DO supply to the net pen water and the bottom water needs to be increased, and the organically enriched sediment just below the net pens needs to be treated.     

Effect of the lateral growth rate on wood properties in fast-growing hardwood species

We investigated the feasibility of using several fast-growing tropical or subtropical hardwood species for timber production by measuring key wood qualities in relationship to the high rates of lateral growth. The trees tested were sampled from even-aged plantations of Acacia mangium, A. auriculiformis, hybrid Acacia (A. mangium × A. auriculiformis), Eucalyptus grandis, E. globulus, and Paraserianthes falcataria (Solomon and Java origin) that had already reached commercial harvesting age. The released strain of the surface growth stress (RS), xylem density (XD), microfibril angle (MFA), and fiber length (FL) were measured at the outermost part of the xylem at breast height in each tree. Results were then compared to the lateral growth rate (radius/age) at breast height, which provides a relative indicator of the amount of tree growth per year. Our findings indicated that RS was constant, regardless of lateral growth rate in each species. Similar results were observed for XD, MFA, and FL, with a few exceptions, suggesting that high growth rates do not intrinsically affect the wood properties of fast-growing tropical or subtropical species that have reached harvesting age. However, special attention must be paid to patterns of xylem maturation when developing plantations of such species.