Fine mapping of the region including hypogonadism (hgn) locus on rat chromosome 10

The hypogonadic rat (hgn/hgn) shows male sterility, reduced female fertility, and renal hypoplasia, controlled by a single recessive gene located on rat chromosome 10. We developed a fine map around the hgn locus using 565 rat backcross progeny and a Rat/Hamster radiation hybrid panel. The hgn locus was linked to Aldoc (aldolase c) and whn (winged helix of nude), and located in a 0.34-cM region between D10Rat30 and D10Rat68. The distance of the region was approximately 840-kb on rat physical map. Neither loci responsible for male sterility nor renal hypoplasia has been mapped on the homologous regions of mouse chromosome 11 and human chromosome 17. Identification of the gene responsible for the hgn mutation would provide important information on urogenital development.     

Associations between Japanese spotted fever (JSF) cases and wildlife distribution on the Boso Peninsula,Central Japan (2006–2017)

Populations of large mammals have been dramatically increasing in Japan, resulting in damage to agriculture, forestry, and ecosystems. However, their effects on tick-borne diseases have been poorly studied. Here, we focused on the relationship between Japanese spotted fever (JSF), a tick-borne disease caused by Rickettsia japonica, and populations of large mammals. To explore factors that affected the area in which JSF cases occur, we used generalized linear mixed models (GLMMs). We demonstrated that the expansion of the area of JSF occurrence can be predicted by deer density and geographical factors, which is likely due to differences in landscape structure. However, the associated models have limitations because of the lack of information about the distribution of vectors and reservoirs. To reduce the risk of humans contracting JSF, potential reservoirs should be confirmed.     

The potential negative impacts of the classical swine fever virus on wild boar population in Gifu prefecture,Japan

There is a possibility that classical swine fever (CSF) virus outbreak has negative impacts on wild boar. To adequately manage native wild boar populations, wildlife managers need to gather the field data on wild boar and implement population management practices. We aimed to report the relative abundance index of wild boar before and after this outbreak. Our results showed that relative abundance index declined from 2017 (8.88 wild boars/100 trap days) to 2019 (2.03 wild boars/100 trap days), because of the negative impact of this virus and continuous culling programs. Although the eradication risk from the synergistic effect is low, wildlife managers need to consider the relationship between the trade-off between the risk of CSF and the conservation ecology risk of native species eradication.     

The enhancement of Th1 immune response by anti-PD-L1 antibody in cattle infected with Mycobacterium avium subsp. paratuberculosis

Johne’s disease, caused by Mycobacterium avium subsp. paratuberculosis (MAP), is a chronic enteritis of ruminants. Previous studies have shown that programmed death-ligand 1 (PD-L1) is associated with the disease progression, and PD-L1 blockade activates MAP-specific Th1 responses in vitro. Here, we performed anti-PD-L1 antibody administration using 2 MAP-infected cattle at the late subclinical stage of infection. After administration, bacterial shedding was reduced or maintained at a low level. Additionally, MAP-specific Th1 cytokine production was upregulated, and CD69 expression was increased in T cells. Collectively, the treatment has a potential as a novel control method against Johne’s disease.     

Sinking rate of loricae of some common tintinnid ciliates

Sinking rate of empty loricae of seven tintinnid species was measured in settling chambers. The sinking rates normalized for 3% NaCl solution at 20d?C are 0.25-2.08 m day^-1 for five hyaline loricae and 1.90 and 15.9 m day^-1 for two agglutinated loricae. Positive relationships between sinking rate and size of hyaline loricae such as volume, surface area and nominal diameter were established, which favour the practical estimation of sinking rate of empty loricae discarded by natural tintinnid populations by measuring size composition. The slower sinking rate of hyaline loricae, compared with that of diatoms, indicates their availability as indicators of particular water masses in the ocean. Loricae incorporated into faecal pellets of zooplankton and marine snow also indicate the origin of these sinking particles.