An epidemic of swine influenza in Japan

In a serological survey of pigs in Japan haemagglutination inhibition (HI) antibody to swine influenza virus (Hsw1N1) was first detected in 721 of 3313 (21.1 per cent) sera in 1977 and 1578 of 4946 (32.1 per cent) in 1978. The virus was prevalent in all districts of Japan but to a different extent. In contrast to the high incidence of antibody, there were few cases of infection with clinical signs and only 13 outbreaks of swine influenza were recognised in Japan from 1978 to 1979. Thirty-seven influenza viruses were isolated from nasal swabs of diseased pigs in 13 outbreaks. The subtype of most isolates was Hsw1N1 but two strains were Hsw1N2.     

Effect of distance from early flowering pollinizers ‘Maypole’ and ‘Dolgo’ on ‘Fiji’ fruit set

An apple orchard consisting of a single cultivar under the condition of natural pollination must have suitable pollinizers such as Crab apples to ensure stable fruit production. We selected ‘Maypole’ and ‘Dolgo’ as pollinizers for the cultivar ‘Fuji’, and investigated the rate of fruit and seeds in ‘Fuji’ fruits produced by pollen of the pollinizers. We developed a method for tracing pollen flow based on the leaf color of progeny and S-RNase allele of ‘Maypole’, and on Simple Sequence Repeat (SSR) analyses of ‘Maypole’ and ‘Dolgo’. These were powerful tools for determining the distance insects (mainly Osmia cornifrons) carry pollen from the pollinizers to ‘Fuji’. Although the fruit set of ‘Fuji’ apples was not reduced with increasing distance between ‘Fuji’ apple trees and pollinizers (probably due to pollen flow from other commercial cultivars planted outside the area), the rate of ‘Fuji’ apple fruit produced by the pollen of the pollinizers decreased with increasing distance. The rate of fruit produced by the pollinizers was 84% and 77% when ‘Fuji’ was 2.5 m from ‘Maypole’ and ‘Dolgo’, respectively, and 71% and 64% when ‘Fuji’ was 5 m from ‘Maypole’ and ‘Dolgo’, respectively, but was reduced to 47% and 39% when ‘Fuji’ was 10 m from ‘Maypole’ and ‘Dolgo’, respectively. However, the spacing could cause reduced fruit size, and require extra fruit thinning for producing large fruits. It could also cause reduction of the yield for increasing the planting area of pollinizers. We recommend that pollinizers should be planted not more than 10 m from ‘Fuji’.     

Relationship between arginine vasopressin and high signal intensity in the pituitary posterior lobe on T1-weighted MR images in dogs

The posterior lobe of the pituitary gland (PL) normally shows characteristic high signal intensity (SI) on T1-weighted MR images (T1WI) in humans. The high SI is thought to represent storage of arginine vasopressin (AVP) in the PL. Normal dogs also show a high SI on T1WIs, but the origin is unclear. In the present study, we investigated whether the high SI in the PL on T1WIs in normal dogs is caused by AVP. We examined the SI in the PL on T1WIs, plasma AVP concentrations and plasma osmolality in normal dogs after excessive AVP secretion was induced by hypertonic saline overload. In addition, functional changes in the supraoptic nucleus and paraventricular nucleus of the hypothalamus under AVP secretion-stimulated conditions were examined immunohistologically. Under hypertonic saline overload, plasma osmolality and plasma AVP concentrations gradually increased, while the SI of the PL gradually decreased. This suggests that AVP secretion was stimulated by elevated osmolality. Moreover, there was a significant negative correlation between plasma AVP concentrations and the SI ratio of the PL. An immunohistochemical study of the hypothalamus nucleus revealed that AVP-immunopositive cells significantly increased in the hypertonic saline loaded dogs. We concluded that the high SI in the PL in T1WIs in normal dogs was caused by AVP stored at the site, and examination of the SI in the PL using MRI is useful for diagnosis of abnormal pituitary glands.     

A new method to quantify how water repellency compromises soils' filtering function

Soil water repellency (SWR) is known to lead to preferential flow and to degrade the soil's filtering efficiency. However, no method is available to quantify directly how SWR affects the transport of reactive solutes. We propose a new method for conducting solute transport experiments in water‐repellent soils. It involves sequentially applying two liquids, one water, the other a reference fully wetting liquid, namely aqueous ethanol, to the same intact soil core with air‐drying between liquids. We applied this approach to quantify the impact of SWR on the filtering of the herbicide 2,4‐Dichlorophenoxyacetic acid (2,4‐D) in two Andosols. In batch experiments conducted prior to the transport experiments, 2,4‐D sorption was not influenced by aqueous ethanol for one soil. However, sorption in the second soil followed the co‐solvency theory, which predicts decreasing sorption with increasing solvent fractions. Thus, sorption experiments are necessary to complement our new method. Breakthrough curves were characterized by preferential flow with large initial concentrations, tailing and a long prevalence of solutes remaining in the soil. In the soil in which 2,4‐D sorption was unaffected by aqueous ethanol, SWR increased 2,4‐D losses by four and 50 times in the first 5‐mm outflow compared with the 2,4‐D losses with water. After 50‐mm outflow, the 2,4‐D losses were similar for one core, but in the other core they were still about four times greater with water than with aqueous ethanol. This method to quantify the reduction of the soil's filtering efficiency by SWR is needed for assessing the increased risk of groundwater contamination by solutes exogenously applied to water‐repellent soils.     

A trial of intrauterine insemination using a fiberscope in the giant panda (Ailuropoda melanoleuca)

An intrauterine insemination technique using a fiberscope was investigated in the giant panda. A septal wall was present about 5 cm from the vulva, the external urethral orifice was present in the ventral region, and the entrance (pseudocervix) to the vagina was present in the dorsal region. The uterovaginal region protruded in the dorsal region about 15 cm from the pseudocervix. The external uterine orifice was present in the uterovaginal region, revealing that intrauterine insemination can be easily performed. This technique may greatly contribute to artificial reproduction of the giant panda.     

Characteristics of frozen-thawed spermatozoa cryopreserved with different concentrations of glycerol in captive Japanese black bears (Ursus thibetanus japonicus)

Seven mature Japanese black bears were used as semen donors, and a total of 7 semen samples collected from the animals by the electroejaculation method were cryopreserved in liquid nitrogen. Egg yolk-TRIS-citrate-glucose extender was used, and the effects of different final concentrations of glycerol, at 4-12% (v/v), on frozen-thawed spermatozoa were examined. No significant difference was observed in percent motility or percent abnormal morphology of frozen-thawed spermatozoa among the different glycerol concentrations. Percent viability and percent intact acrosomes of spermatozoa cryopreserved with 4 and 6% glycerol were significantly higher than those with 10 and 12% glycerol. These results suggest that a suitable glycerol concentration for freezing Japanese black bear semen within the range tested would be 4-6%.     

Identification of QTL controlling post-flowering period in soybean

The length of the reproductive period affects the grain yield of soybean (Glycine max [L.] Merr), and genetic control of the period might contribute to yield improvement. To detect genetic factor(s) controlling the reproductive period, a population of recombinant inbred lines (RILs) was developed from a cross between Japanese landrace ‘Ippon-Sangoh’ and, Japanese cultivar ‘Fukuyutaka’ which differ in their duration from flowering to maturation (DFM) relative to the difference in the duration from sowing to flowering (DSF). In the RIL population, the DFM correlated poorly (r = −0.16 to 0.34) with the DSF in all field trials over 3 years. Two stable QTLs for the DFM on chromosomes (Chr-) 10 and 11 as well as two stable QTLs for the DSF on Chr-10 and -16 were identified. The QTL on Chr-11 for the reproductive period (designated as qDfm1; quantitative trait locus for duration from flowering to maturation 1) affected all three trials, and the difference in the DFM between the Fukuyutaka and Ippon-Sangoh was mainly accounted for qDfm1, in which the Fukuyutaka allele promoted a longer period. qDfm1 affected predominantly the reproductive period, and thus it might be possible to alter the period with little influence on the vegetative period.     

High susceptibility of Djungarian hamsters (Phodopus sungorus) to the infection with Babesia microti supported by hemodynamics

As the comparative study was carried out on the susceptibility by the pursuit of parasitemia among the Djungarian, Syrian, and Chinese hamsters as well as BALB/c mice infected with the Syrian hamster-adapted Babesia microti strain, and Djungarian hamsters showed the highest parasitemia among them. Then, the other hematological parameters were pursued in the Djungarian hamsters infected with the hamster-adapted B. microti strain. Remarkable symptoms observed were hemoglobinuria clinically, anemia hematologically, and splenomegaly macroscopically during all over the observation period for 24 weeks post infection (PI). Parasitemia began to rise at 2 weeks and peaked at 4 weeks PI. After that, parasitemia decreased gradually but was maintained with a level of about 10% on average until 24 weeks PI at the end of the experiment. A decrease in the RBC count, Hb, and PCV, and an increase in the reticulocyte and WBC counts due to the development of immature neutrophils, lymphocytes and monocytes were recognized together with a rise of parasitemia. The hamsters had macrocytic hypochromic anemia due to the increase of MCV and the decrease of MCHC in the growth phase of the parasite. It was considered that the Djungarian hamsters will be useful for the infection examination, isolation, maintenance, and passage of B. microti in laboratory.     

Susceptibility of Chinese hamsters (Cricetulus griseus) to the infection of Babesia microti

Chinese hamsters were examined for the susceptibility to the infection with Babesia microti based on the hematological parameters during the course of infection. A marked decrease in the RBC count, Ht value, Hb concentration, and an increase in WBC count due to the development of neutrophils or monocytes were recognized with the progress of parasitemia. Remarkable clinical findings were anemia and persistent infection with a low level of parasite burden in the chronic and convalescent stages. From these findings, it was concluded that Chinese hamsters were susceptible to infection with B. microti and would be useful for infection examination with the parasite.     

Effects of introgressions from <Emphasis Type="Italic">Festuca pratensis</Emphasis> on winter hardiness of <Emphasis Type="Italic">Lolium perenne</Emphasis>

Previous studies reported that some genotypes with introgressed Festuca chromosome segment(s) in Lolium genome showed enhanced winter hardiness compared to Lolium. The aim of this study was to search comprehensively for the Festuca pratensis chromosome regions affecting winter hardiness-related traits when introgressed into the Lolium perenne genome. Association between F. pratensis introgression and winter hardiness-related traits (fall and winter hardiness indexes, early-spring dry matter yield, and freezing tolerance) were screened in the diploid introgression populations (n = 203) that had some F. pratensis chromosome segments introgressed. Eighty-four intron markers corresponding to unique rice genes randomly distributed across the genome were used for genotyping. Winter hardiness of almost all plants in the introgression populations was lower than that of the F. pratensis and triploid hybrid parents, but the average was higher than that of L. perenne. A significant positive effect of F. pratensis introgression on early-spring dry matter yield was detected on chromosome 7. This quantitative trait locus (QTL) was confirmed by linkage analysis using a backcross population with F. pratensis introgression in the target region of chromosome 7. However, the contribution of the newly identified QTL was rather small (6.7–9.6%), suggesting that superior winter hardiness of F. pratensis compared to L. perenne is conferred by multiple small-effect QTLs. We also detected a previously unreported negative effect of Festuca introgression on winter hardiness. Newly obtained QTL information in this study would contribute to the design of Festuca/Lolium hybrid breeding.