Epidemiological study of Kabuto Mountain virus,a novel uukuvirus,in Japan

Kabuto Mountain virus (KAMV), the new member of the genus Uukuvirus, was isolated from the tick Haemaphysalis flava in 2018 in Japan. To date, there is no information on KAMV infection in human and animals. Therefore, serological surveillance of the infection among humans and wild mammals was conducted by virus-neutralization (VN) test and indirect immunofluorescence assay (IFA). Sera of 24 humans, 59 monkeys, 171 wild boars, 233 Sika deer, 7 bears, and 27 nutria in Yamaguchi Prefecture were analyzed by VN test. The positive ratio of humans, monkeys, wild boars, and Sika deer were 20.8%, 3.4%, 33.9% and 4.7%, respectively. No positive samples were detected in bears and nutria. The correlation coefficients between VN test and IFA in human, monkey, wild boar, and Sika deer sera were 0.5745, 0.7198, 0.9967 and 0.9525, respectively. In addition, KAMV was detected in one pool of Haemaphysalis formosensis ticks in Wakayama Prefecture. These results indicated that KAMV or KAMV-like virus is circulating among many wildlife and ticks, and that this virus incidentally infects humans.     

Biobleaching of unbleached and oxygen-bleached hardwood kraft pulp by culture filtrate containing manganese peroxidase and lignin peroxidase fromPhanerochaete chrysosporium

Unbleached and oxygen-bleached hardwood kraft pulp (UKP and OKP), respectively, were bleached with a culture filtrate containing manganese peroxidase (MnP) and lignin peroxidase (LiP) fromPhanerochaete chrysosporium Burds. The brightness increases of UKP upon biobleaching with the culture filtrate with and without MnSO₄ were the same. The brightness increase of OKP with MnSO₄ decreased to about half that seen without MnSO₄. Changes in the brightness of UKP and OKP by treatment with the culture filtrate were determined. The brightness increased sharply by about eight points during the first 3h. The 3-h treatment was repeated seven times. The brightness increased linearly with the bleaching of UKP. On bleaching of OKP, the brightness increased slowly and stopped at about 78%.Part of this report was presented at the 62nd Pulp and Paper Research Conference of the Japan Tappi, Tokyo, June 1995     

Embryo implantation is blocked by intraperitoneal injection with anti-LIF antibody in mice

Leukemia inhibitory factor (LIF) is essential for embryo implantation in mice and plays an important role in other mammals including humans. Intraperitoneal (i.p.) injections with anti-LIF antibody (7.5 μg/g body weight, 3 times) between D3 (D1 = day of vaginal plug detection) and D4 effectively blocked embryo implantation; complete inhibition was achieved in C57BL/6J mice, and implantation was dramatically reduced in ICR mice (reduced to 27%). Normal rabbit IgG used as the control did not disturb embryo implantation. Anti-LIF antibody was localized not only in the stroma, but also in the luminal epithelium and the glandular lumen after i.p. injections. Growth-arrested blastocysts were recovered from the uterus without any implantation sites in both strains. Blastocysts made contact with the LE on the antimesometrial side; however, uterine stromal cells did not undergo secondary decidual reaction, and the uterine lumen was open, even at D7. Several regions of decidualization in ICR mice treated with anti-LIF antibody were smaller than those of the control, and development of blastocysts was delayed. The expression of LIF-regulated genes, such as immune-responsive gene-1 and insulin-like growth factor binding protein-3, was significantly decreased in C57BL/6J mice treated with anti-LIF antibody compared with the control, but not in ICR mice. The present study demonstrated that simple ip injections of an antibody are sufficient to block one of the important factors involved in embryo implantation in mice, and this method should also be easily applicable to the investigation of other factors involved in implantation.     

Differentiation of uterine natural killer cells in pregnant SCID (scid/scid) mice

To determine whether functional T- and B-cells can affect differentiation and/or proliferation of uterine natural killer (uNK) cells, their numbers in SCID mice (genotype, C.B.-17/Icr-scid/scid) were compared with those of control mice (genotype, C.B.-17/Icr-+/+) on days 8, 12 and 16 of pregnancy. Using biotinylated-Dolichos biflorus agglutinin (DBA) lectin staining, uNK cells can be readily classified into 4 subtypes, I to IV, from immature to mature types. The number of uNK cells was significantly lower in the decidua basalis of SCID mice than in that of control mice on day 8 of pregnancy. Particularly, the number of uNK cells of immature subtype II was significantly lower in SCID mice than in the control mice. By day 12, however, the uNK cell number in the SCID mice reached the same level as that of the control mice. It is likely that uNK cell differentiation in SCID mice was delayed during the early placentation period due to a lack of functional T and B cells.     

Changes in the amount of proteins, glycogen and lipids in porcine oocytes during in vitro meiotic maturation

Changes in the cytoplasmic inclusions during meiotic maturation were histochemically examined in cultured porcine oocytes. The oocytes contained a small amount of protein and glycogen granules throughout the maturation culture, as well as Sudanophilic lipids composed of small, medium and large droplets. Soon after collection, the amount of Sudanophilic lipid droplets of small and medium size was small and there were 167 ± 11.2 large droplets. After being cultured for 22 h, the number of large lipid droplets decreased remarkably, while the number of small and medium ones increased. There were no differences in the number of Sudanophilic lipid droplets of different sizes between ovulated oocytes and the oocytes cultured for 44 h. The oocytes always contained a large amount of neutral fats and lipoids, but not cholesterols. In the oocytes cultured for 22 h with olomoucine, both the resumption of nuclear maturation and the decrease in the size of the Sudanophilic lipid droplets were inhibited. From the present findings, it appears that the change in the size of the Sudanophilic lipid droplets in the cytoplasm of porcine oocytes is closely related to nuclear maturation.     

Effect of components of green tea extracts, caffeine and catechins on hepatic drug metabolizing enzyme activities and mutagenic transformation of carcinogens

Green tea contains catechins and caffeine as major constituents. Treatment of rats with green tea (2.5% w/v) significantly increased 7-ethoxycoumarin O-deethylase (7-ECOD), caffeine N-1 demethylase (CN1D) and UDP-glucuronyltransferase (UGT) activities. Treatment with caffeine similarly activated CYP1A2 and related monooxygenases as well as UGT, while treatment with catechins induced UGT activity but not 7-ECOD or CN1D activity. Numbers of benzo[a]pyrene (BP)-induced revertant colonies in an Ames test (mutation assay) with S. typhimurium TA98 as the test strain were markedly larger when BP was preincubated with the liver S-9 (9000 x g supernatant of liver homogenate) from green tea-treated rats than when preincubated with that from control rats. In a modified Ames assay system in which UGT was activated by the addition of UDP-glucuronic acid to the preincubation mixture, the numbers of revertant colonies in the assay using liver S-9 from green tea-treated rats decreased to a similar level to that in the assay using S-9 from controls. The acceleration of two enzymatic reactions may contribute to the rapid elimination of BP; the first step, the formation of a metabolic intermediate (which is mutagenic) by CYP1A2 and the second, the conjugation of active metabolic intermediates by UGT. We speculated that green tea can reduce the amount of time carcinogens reside in the body and the chance that body tissues will be exposed to active metabolites of carcinogens thorough rapid elimination due to the simultaneous induction of CYP1A2 and UGT activities.     

Iodine intake as a possible cause of discontinuous decline in sperm counts: a re-evaluation of historical and geographic variation in semen quality

In order to examine whether iodine supplements may have caused a global decline in sperm concentrations during the past several decades, the synchronicity of the decline in mean sperm counts and the introduction of iodine supplements was analyzed statistically. A positive correlation between the incidence of thyroid disease and sperm counts has been detected in Europe. In addition, it has been shown that sperm counts began falling around 1965 in the United States, 40 years after iodine supplements were introduced. Mean sperm counts before and after 1965 were 111 x 10(6)/ml and 70 x 10(6)/ml, respectively, in calculations weighted by the number of subjects included in each individual publication. The timing of the declines coincided with the introduction of iodine supplements in the United States, France, and the United Kingdom. The implications are that the global decline in sperm concentrations may be caused by iodine intake. Geographical variation in the types of sperm count decline also appears to be present.     

Establishment of a LacZ marker rescue assay to detect infectious RD114 virus

Cats have an infectious endogenous retrovirus, named RD114 virus, and there is a possibility that RD114 virus has contaminated live attenuated vaccines, for which feline cells are used as a substrate. To monitor infectious RD114 virus in vaccines for cats, we developed a LacZ marker rescue assay to detect infectious RD114 virus. Among four human cell lines examined, TE671 cells (human rhabdomyosarcoma) were most susceptible to RD114 virus and supported RD114 replication efficiently. Infection was enhanced approximately 5 times by the addition of polybrene at concentrations of 2 to 8 microg/ml in the medium during viral adsorption. A 4-hr viral adsorption period was sufficient to obtain the maximum titer. By inoculating samples into TE671 cells transduced with the lacZ marker gene, the limiting diluted sample (i.e., less than 10 infectious units) was detected at 12 days post-inoculation by the LacZ marker rescue assay. Based on the results obtained in this study, we propose a standard protocol of the LacZ marker rescue assay to detect infectious RD114 virus.     

Detection of feline norovirus using commercial real-time RT-PCR kit for the diagnosis of human norovirus infection

Feline noroviruses (FNoVs) are potential clinical pathogens in cats. To perform an epidemiological study of FNoV infection, it is necessary to develop a simple and effective method for virus detection. We investigated whether a commercial human NoV quantitative RT-PCR kit for the detection of human NoVs used in medical practice can be applied for FNoV detection. This kit was capable of detecting the FNoV gene regardless of the genogroup (GIV and GVI) in experimental and field samples. Based on the above findings, it is possible to detect FNoVs using human NoV tests. The relationship between FNoV infection and gastroenteritis in cats may be clarified by applying these methods to an epidemiological survey of FNoVs.