Growth Complementation of hrpXo Mutants of Xanthomonas oryzae pv. oryzae by Virulent Strains in Rice Cultivars Resistant and Susceptible to the Parental Strain

Xanthomonas oryzae pv. oryzae (X. o. pv. oryzae) T7174 is virulent on rice cultivar IR24 and avirulent on IR-BB2. From recent reports, some virulence and avirulence factors of plant pathogenic bacteria are transferred to plant cells through the hrp-dependent type III secretion system. In this study, we investigated the involvement of hrp genes in the compatible and the incompatible interactions between rice and X. o. pv. oryzae after co-inoculation with hrpXo mutants derived from T7174 and virulent strains. Growth of the mutants, named 74ΔHrpXo and 76ΔHrpXo, was repressed in IR24 when the mutants were applied alone. However, growth of the mutants was complemented by co-inoculation with virulent strains. Growth of bioluminescent hrpXo mutant 76ΔHrpXo in IR24 and its growth in IR-BB2 after co-inoculation with T7133, which is virulent on both cultivars, was equally complemented, as detected by bioluminescence from the mutant. On the other hand, only partial complementation of growth of T7174L76, which is a bioluminescent and pathogenic derivative of T7174, by T7133 was observed in IR-BB2. Thus, growth of the hrpXo mutant of X. o. pv. oryzae was complemented by virulent strains in both susceptible and resistant rice leaves with the parental strain. Received 21 July 2000/ Accepted in revised form 26 October 2000     

Residence pattern of the ayu <Emphasis Type="Italic">Plecoglossus altivelis</Emphasis><Emphasis Type="Italic">altivelis</Emphasis> larvae and juveniles occurring in the surf zone of a sandy beach,Niigata Prefecture,northern Sea of Japan

This study examined the residence pattern of ayu larvae and juveniles occurring in the surf zone of an extensive sandy beach, in the north part of the Sea of Japan. In this region, ayu larvae mainly hatched in October and November, generally appeared in the surf zone in hatching order, and were continuously present until the following January. During a short period after mid- to late January when the water temperature fell below 10°C, ayu larvae and juveniles concurrently migrated from the surf zone regardless of their size and age, resulting in a longer term residence for earlier-hatched ayu. This was in contrast to studies in other waters, which found that early-hatched ayu have a short-term residence and late-hatched a long-term residence. Furthermore, faster growth that enables ayu to reach the maximum residence size (around 40 mm BL) in the surf zone during the period when the water temperature was still over 10°C might lead to earlier migration and a shorter residence term. This process might be applicable only to the early-hatched group (defined as individuals hatched in late September and October) and depends on the size of each individual, thus leading to a gradual migration of larger individuals as they attain maximum residence size.     

Interaction between the helicase domain of the tobacco mosaic virus replicase and a tobacco arginine decarboxylase

In a yeast two-hybrid screening test for tobacco proteins that interact with TMV replicase using the helicase (H) domain as bait, a cDNA clone was selected that encodes a polyamine biosynthetic enzyme, arginine decarboxylase (ADC). In yeast cells, the C-terminal internal region of ADC interacted with the H domain. This observation was confirmed in vitro by far-Western blotting. Inhibition of the binding between the H domain and the IRnHEL (I region and N-terminus of helicase domain) region by ADC using a yeast three-hybrid assay suggested possible interference of the heterodimerization of 126K and 183K by ADC.The nucleotide sequence data of pADCF reported in this study is available in the DDBJ/EMBL/GenBank databases under accession number AB110952     

Effects of polyline simplification of dynamic GPS data under forest canopy on area and perimeter estimations

The objectives of this study were to determine Global Positioning System (GPS) positional errors while moving under the forest canopy and to clarify the effects of polyline simplification on area and perimeter estimations. We used the Pathfinder Pro XR and GPSMAP 76S, which are categorized as “high-end mapping” and “general navigation” GPS receivers, respectively. The field tests were conducted in both natural and plantation forests. The results showed that the Pathfinder Pro XR, which has better multipath rejection technology, worked well, especially in the plantation forest under unfavorable conditions of higher stand density. We used analysis of variance to clarify the effects of the receiver type, positioning mode, stand type, and polyline simplification method on area and perimeter estimations. The receiver type and positioning mode were found to be significant factors that affected area estimation. The Pathfinder Pro XR estimated the area more accurately than the GPSMAP 76S, and differential GPS estimated the area more accurately than autonomous GPS. With respect to the perimeter, the receiver type, positioning mode, and polyline simplification method were found to be significant factors. The results showed that perimeter estimation was improved by using the velocity filter, and further improved by using the velocity filter and Douglas-Peucker algorithm, especially when the Pathfinder Pro XR was used. The GPSMAP 76S estimated the perimeter accurately without any filtering because its default speed filter worked well, even though the GPSMAP 76S is a general navigation GPS receiver.     

Application of cationic polymer prepared from sulfuric acid lignin as a retention aid for usual rosin sizes to neutral papermaking

Cationic polymers that acted as the retention aids for usual rosin sizes in neutral papermaking were prepared from sulfuric acid lignin (SAL), one type of acid lignin. To convert SAL to the cationic polymer (MP-SAL), SAL was phenolated and then treated by the Mannich reaction to introduce the amino groups. In the MP-SAL single system, MP-SAL exhibited high sizing effectiveness in neutral papermaking with the rosin emulsion size. However, MP-SAL showed no sizing effectiveness when soap rosin size was used. MP-SAL showed increased sizing effectiveness as the pK _a of the introduced amino group increased. From this and comparison of the sizing degrees of MP-SAL and polyethylenimine, which possesses a linear structure, it was suggested that the sizing effectiveness was not only affected by the charge density and molecular weight, but also by the basicity of the introduced amino groups and the molecular structure of the retention aid. In the alum–MP-SAL dual system, alum and MP-SAL synergistically enhanced the sizing effectiveness in the rosin emulsion sizing at neutral pH. In turn, this allowed a decrease in the MP-SAL dosage and resulted in a small decrease in brightness.Part of this report was presented at the 48th Lignin Symposium, October 2003, Fukui     

A molecular epidemiological survey of Babesia, Hepatozoon,Ehrlichia and Anaplasma infections of dogs in Japan

Tick-borne diseases are often encountered in canine clinical practice. In the present study, a molecular epidemiological survey of dogs in Japan was conducted to understand the prevalence and geographical distribution of Babesia spp., Hepatozoon spp., Ehrlichia spp. and Anaplasma spp. Pathogen-derived DNA in blood samples obtained from 722 dogs with a history of exposure to ticks and/or fleas was examined by PCR. The prevalence of Babesia gibsoni, Babesia odocoilei-like species, Hepatozoon canis and Ehrlichia spp./Anaplasma spp. was 2.4% (16/722), 0.1% (1/722), 2.5% (18/722) and 1.5% (11/722), respectively. While B. gibsoni and Ehrlichia spp./Anaplasma spp. were detected in the western part of Japan, H. canis was detected in Tohoku area in addition to western and central parts of Japan.