Resistance of KIR ligand-missing leukocytes to natural killer cells in vivo in patients with acquired aplastic anemia

金沢大学医薬保健研究域医学系　Graduate School of Medical SciencesThe loss of killer cell immunoglobulin-like receptor-ligands (KIR-Ls) due to the copy number neutral loss of heterozygosity of chromosome 6p (6pLOH) in leukocytes of patients with acquired aplastic anemia (AA) may alter the susceptibility of the affected leukocytes to NK cell killing in vivo. We studied 408 AA patients, including 261 who were heterozygous for KIR-Ls, namely C1/C2 or Bw6/Bw4, for the presence of KIR-L-missing (KIR-L[-]) leukocytes. KIR-L(-) leukocytes were found in 14 (5.4%, C1, n= 4, C2, n=3, and Bw4, n= 7) of the 261 patients, in whom corresponding KIR(+) licensed NK cells were detected. The incidence of 6pLOH in the 261 patients (18.0%) was comparable to that in 147 patients (13.6%) who were homozygous for KIR-L genes. The percentages of HLA-lacking granulocytes (0.8-50.3%, median 15.2%) in the total granulocytes of the patients with KIR-L(-) cells were significantly lower than those (1.2-99.4%, median 55.4%) in patients without KIR-L(-) cells. KIR2DS1 and KIR3DS1 were only possessed by three of the 14 patients, two of whom had C2/C2 leukocytes after losing C1 alleles. The expression of the KIR3DS1 ligand HLA-F was selectively lost on KIR-L(-) primitive hematopoietic stem cells (HSCs) derived from 6pLOH(+) iPS cells in one of the KIR3DS1(+) patients. These findings suggest that human NK cells are able to suppress the expansion of KIR-L(-) leukocytes but are unable to eliminate them partly due to the lack of activating KIRs on NK cells and the low HLA-F expression level on HSCs in AA patients.Embargo Period 6 month

Seasonal changes in zooplankton abundance, biomass, size structure and dominant copepods in the Oyashio region analysed by an optical plankton counter

To identify seasonal patterns of change in zooplankton communities, an optical plankton counter (OPC) and microscopic analysis were utilised to characterise zooplankton samples collected from 0 to 150 m and 0 to 500 m in the Oyashio region every one to three months from 2002 to 2007. Based on the OPC measurements, the abundance and biomass of zooplankton peaked in June (0–150 m) or August (150–500 m), depending on the depth stratum. The peak periods of the copepod species that were dominant in terms of abundance and biomass indicated species-specific patterns. Three Neocalanus species (Neocalanus cristatus, Neocalanus flemingeri and Neocalanus plumchrus) exhibited abundance peaks that occurred before their biomass peaks, whereas Eucalanus bungii and Metridia pacifica experienced biomass peaks before their abundance peaks. The abundance peaks corresponded to the recruitment periods of early copepodid stages, whereas the biomass peaks corresponded to the periods when the dominant populations reached the late copepodid stages (C5 or C6). Because the reproduction of Neocalanus spp. occurred in the deep layer (>500 m), their biomass peaks were observed when the major populations reached stage C5 after the abundance peaks of the early copepodid stages. The reproduction of E. bungii and M. pacifica occurred near the surface layer. These species first formed biomass peaks of C6 and later developed abundance peaks of newly recruited early copepodid stages. From the comparison between OPC measurements and microscopic analyses, seasonal changes in zooplankton biomass at depths of 0–150 m were governed primarily by E. bungii and M. pacifica, whereas those at depths of 150–500 m were primarily caused by the three Neocalanus species

SEASONAL AND INTER-SPECIES COMPARISON OF ASYMMETRY IN THE GENITAL SYSTEM OF SOME SPECIES OF THE OCEANIC COPEPOD GENUS METRIDIA (COPEPODA, CALANOIDA)

The seasonal and inter-annual changes in the asymmetry of female insemination and the male leg 5 of the planktonic calanoid copepods Metridia okhotensis and M. pacifica were investigated in the Okhotsk Sea. An inter-species comparison of both parameters was also carried out on seven Metridia species collected from oceans throughout the world. For M. okhotensis from the Okhotsk Sea, most of the females showed left-side insemination (annual average: 95.7%) and most of the males showed left-side asymmetry (99.7%) of the long inner process of the second exopodal segment in the fifth leg throughout the year. However, sympatric M. pacifica showed different ratios of asymmetry for female insemination and male morphotypes with a left : right = 1 : 2 ratio throughout the year. For the seven Metridia species from the global oceans treated in this study, ratios of asymmetry for female insemination and male morphotypes were correlated with each other. One-sided insemination (i.e., only left or only right insemination) was a common pattern for various Metridia species from global oceans, but their ratios varied by species. Previously, low hatching rates (29-68%) of eggs were reported for various Metridia spp. in laboratory experiments, but the reasons for these low rates were unclear. Because each spermatheca of Metridia spp. is connected to the oviduct on the same side, either left or right, this suggests that half of the eggs produced by unilaterally inseminated females remain unfertilized. The morphology of the genital structures and literature data of the egg hatching rates of Metridia spp. indicate that almost half of the eggs produced by females are not viable and are, thus, wasted

Spatial and temporal changes in zooplankton abundance, biovolume, and size spectra in the neighboring waters of Japan : analyses using an optical plankton counter

Background An optical plankton counter (OPC) was used to examine spatial and temporal changes in the zooplankton size spectra in the neighboring waters of Japan from May to August 2011. Results Based on the zooplankton biovolume of equivalent spherical diameter (ESD) in 45 bins for every 0.1 mm between 0.5 and 5.0 mm, a Bray-Curtis cluster analysis classified the zooplankton communities into six groups. The geographical distribution of each group varied from each of the others. Groups with a dominance of 4 to 5 mm ESD were observed in northern marginal seas (northern Japan Sea and Okhotsk Sea), while the least biovolume with a dominance of a small-size class (0.5 to 1 mm) was observed for the Kuroshio extension. Temporal changes were observed along the 155° E line, i.e., a high biovolume group dominated by 2 to 3 mm ESD during May shifted to other size spectra groups during July to August. These temporal changes were caused by the seasonal vertical descent of dominant large Neocalanus copepods during July to August. As a specific characteristic of the normalized biomass size spectra (NBSS), the slope of NBSS was moderate (−0.90) for the Neocalanus dominant spring group but was at −1.11 to −1.24 for the other groups. Theoretically, the slope of the NBSS of the stable marine ecosystem is known to settle at approximately −1. Conclusions Based on the analysis by OPC, zooplankton size spectra in the neighboring waters of Japan were separated into six groups. Most groups had −1.11 to −1.24 NBSS slopes, which were slightly higher than the theoretical value (−1). However, one group had a moderate slope of NBSS (−0.90) caused by the dominance of large Neocalanus copepods