Intracellular CD154 expression reflects antigen-specific CD8+ t cells but shows less sensitivity than intracellular cytokine and MHC tetramer staining

A recent report showed that analysis of CD154 expression in the presence of the secretion inhibitor Brefeldin A (Bref A) could be used to assess the entire repertoire of antigen-specific CD4(+) T helper cells. However, the capacity of intracellular CD154 expression to identify antigen-specific CD8(+) T cells has yet to be investigated. In this study, we compared the ability of intracellular CD154 expression to assess antigen-specific CD8(+) T cells with that of accepted standard assays, namely intracellular cytokine IFN-gamma staining (ICS) and MHC class I tetramer staining. The detection of intracellular CD154 molecules in the presence of Bref A reflected the kinetic trend of antigen-specific CD8+ T cell number, but unfortunately showed less sensitivity than ICS and tetramer staining. However, ICS levels peaked and saturated 8 h after antigenic stimulation in the presence of Bref A and then declined, whereas intracellular CD154 expression peaked by 8 h and maintained the saturated level up to 24 h post-stimulation. Moreover, intracellular CD154 expression in antigen-specific CD8+ T cells developed in the absence of CD4(+) T cells changed little, whereas the number of IFN-gamma-producing CD8(+) T cells decreased abruptly. These results suggest that intracellular CD154 could aid the assessment of antigen-specific CD8(+) T cells, but does not have as much ability to identify heterogeneous CD4(+) T helper cells. Therefore, the combined analytical techniques of ICS and tetramer staining together with intracellular CD154 assays may be able to provide useful information on the accurate phenotype and functionality of antigen-specific CD8(+) T cells.     

Influence of land consolidation on aquatic invertebrate communities and their distribution patterns in Korean rice fields

Rice fields, the major cropland in South Korea, provide an important wetland habitat for a diverse wildlife and contribute to biodiversity conservation. On the other hand, land consolidation conducted to increase agricultural production since the 1960s on a nationwide scale in South Korea has frequently been suggested to be one of the factors in the decline of biodiversity in agricultural ecosystems. Negative effects of habitat manipulation such as land consolidation would have influenced paddy field biodiversity, but the degree has not been clearly measured in South Korea. This study evaluated the impacts of land consolidation on the aquatic invertebrate biodiversity and investigated their patterns across the nation. Field sampling for biodiversity and environmental variables were made from 290 sites of paddy field over the country. Aquatic invertebrate communities were clustered into four major clusters showing land consolidation as the main factor and geographic location as the second factor. Species richness and abundance were significantly lower in the land consolidation fields (mean ± s.e., 12.80 ± 0.28 vs 88.89 ± 0.89 and 2027.15 ± 150.84 vs 2573.54 ± 572.16). Shannon diversity index was also significantly lower in land consolidation fields. Our results suggest that land consolidation and spatial location are important for biodiversity and conservation of the aquatic invertebrate assemblages in Korean rice fields.     

Subspecies and units for conservation and management of the northern bobwhite in the eastern United States

The northern bobwhite (Colinus virginianus) is a small game bird with sedentary lifestyle and has experienced population declines throughout most of its native distribution in the eastern United States. We investigated intraspecific genetic relationships among 14 local populations covering four putative subspecies (C. v. marilandicus, C. v. virginianus, C. v. mexicanus, and C. v. floridanus) in the United States. Analysis of mitochondrial DNA sequences revealed a small, but significant, genetic structure of northern bobwhite populations or subspecies in the eastern US. However, our results did not support current subspecies limits as distinct evolutionarily significant units, based on the amount of population genetic divergences and insufficient lineage sorting of mtDNA haplotypes among subspecies. Instead, our results suggest that C. v. virginianus, C. v. marilandicus, and C. v. mexicanus be merged into a single management unit, and C. v. floridanus be considered as another distinct unit for conservation and management.     

A new method of studying predatory nematodes using a micropore system

We developed an innovative micropore system that enables us to directly observe the constrained behaviour of predatory nematodes. The results show that the new system provides a suitable environment for modelling the potential effects of these animals as biocontrol agents in their natural habitat.     

Progressive hypoxia-on-a-chip: An in vitro oxygen gradient model for capturing the effects of hypoxia on primary hepatocytes in health and disease

Oxygen is vital to the function of all tissues including the liver and lack of oxygen, that is, hypoxia can result in both acute and chronic injuries to the liver in vivo and ex vivo. Furthermore, a permanent oxygen gradient is naturally present along the liver sinusoid, which plays a role in the metabolic zonation and the pathophysiology of liver diseases. Accordingly, here, we introduce an in vitro microfluidic platform capable of actively creating a series of oxygen concentrations on a single continuous microtissue, ranging from normoxia to severe hypoxia. This range approximately captures both the physiologically relevant oxygen gradient generated from the portal vein to the central vein in the liver, and the severe hypoxia occurring in ischemia and liver diseases. Primary rat hepatocytes cultured in this microfluidic platform were exposed to an oxygen gradient of 0.3–6.9%. The establishment of an ascending hypoxia gradient in hepatocytes was confirmed in response to the decreasing oxygen supply. The hepatocyte viability in this platform decreased to approximately 80% along the hypoxia gradient. Simultaneously, a progressive increase in accumulation of reactive oxygen species and expression of hypoxia-inducible factor 1α was observed with increasing hypoxia. These results demonstrate the induction of distinct metabolic and genetic responses in hepatocytes upon exposure to an oxygen (/hypoxia) gradient. This progressive hypoxia-on-a-chip platform can be used to study the role of oxygen and hypoxia-associated molecules in modeling healthy and injured liver tissues. Its use can be further expanded to the study of other hypoxic tissues such as tumors as well as the investigation of drug toxicity and efficacy under oxygen-limited conditions.     

Canopy-cover thematic-map generation for Military Map products using remote sensing data in inaccessible areas

Canopy cover is one of the most important elements in concealing military structures and enemy reconnaissance. In this study, we propose an algorithm for automatic generation of density measure of percent canopy cover, which is an attribute of the digital Military Map product, using high-resolution satellite images of inaccessible areas. The thematic mapping process of canopy cover can be divided into image classification, segmentation, and texture analysis. QuickBird and SPOT-5 high-resolution images are classified using Landsat images and military maps. Then, forested areas are extracted from the classified images, and closing and opening operations are executed through morphology filtering. The extracted region is divided into unit-zone objects using a segmentation technique, and the percentage of canopy cover of each object is categorized as one of four levels (0–25, 26–50, 51–75, 76–100%). Two methods were used to establish the percentage of canopy cover for each segment: the discriminant method, using statistical analysis, and the classified canopy ratio method, which calculates the percentage of forest in the segment. The discriminant method showed 48% (QuickBird) and 61% (SPOT-5) accuracy and classified canopy ratio method showed 71% (QuickBird) and 87% (SPOT-5) accuracy.     

A case of active incomplete biliary cirrhosis in an aged female Japanese macaque (Macaca fuscata)

We describe the first case of biliary cirrhosis in Japanese macaque. Clinical signs had not been detected. The liver was nodular. Histopathologically, portal‐to‐portal pattern of fibrosis might have indicated chronic cholestasis. Fibrotic septa were infiltrated with inflammatory cells. Therefore, this case could be diagnosed as active incomplete biliary cirrhosis.     

Effect of Crystal Orientation and Conduction Band Grading of Absorber on Efficiency of Cu(In,Ga)Se2 Solar Cells Grown on Flexible Polyimide Foil at Low Temperature

Flexible Cu(In,Ga)Se₂ (CIGS) solar cells are developed on polyimide (PI) foil by using a three‐stage co‐evaporation method. To deposit CIGS on a PI substrate, low temperature deposition process (below 440 °C) is investigated. By optimizing the three‐stage process, power conversion efficiency (PCE) values of 12.1% and 13.6% are obtained at maximum process temperatures of 400 °C and 440 °C, respectively (without anti‐reflection coating). The CIGS absorber deposited at 400 °C is grown with (220)/(204) rather than (112) as its dominant growth orientation, accompanied by highly homogeneous crystal structure and phases. Admittance spectroscopy reveals that the defect levels were lower in the CIGS absorber with (220)/(204) dominant growth orientation, which could have contributed to the PCE of 12.1%. The CIGS solar cell deposited at a temperature of 440 °C exhibits worse defect characteristics compared to that fabricated at 400 °C. However, the CIGS solar cell fabricated below 440 °C exhibited marginal double‐grading of Ga/(Ga + In) in the absorber layer, which resulted in an improved PCE of 13.6%. This result implies that at a temperature below 440 °C, the double‐grading of Ga/(Ga + In) is the more dominant factor causing the PCE improvement above 13%.