A novel Ly6C/Ly6G-based strategy to analyze the mouse splenic myeloid compartment

Currently, there is no standardized panel for immunophenotyping myeloid cells in mouse spleen using flow cytometry. Markers such as CD11b, CD11c, F4/80, Gr-1, Ly6C, and Ly6G have long been used to identify various splenic cell myeloid populations. Flow cytometry and fluorescence-activated cell sorting (FACS) analysis demonstrated that Ly6G/Ly6C markers are superior to Gr-1 for identifying splenic neutrophils, eosinophils, and subsets of monocytes/macrophages. Moreover, these experiments showed that F4/80 is not required for identifying these myeloid subsets and that many of the commercially available preparations of anti-F4/80 antibodies stain poorly for this antigen in spleen. Taken together, we have now developed an informative flow cytometry panel that can be combined with other cell markers to further delineate subpopulations of mouse splenic myeloid cells. This panel will be highly useful to investigators in the flow cytometry field, as there is a critical need to standardize the analysis of myeloid cell subsets.     

Global and Local Concerns: What Attitudes and Beliefs Motivate Farmers to Mitigate and Adapt to Climate Change?

In response to agriculture''s vulnerability and contribution to climate change, many governments are developing initiatives that promote the adoption of mitigation and adaptation practices among farmers. Since most climate policies affecting agriculture rely on voluntary efforts by individual farmers, success requires a sound understanding of the factors that motivate farmers to change practices. Recent evidence suggests that past experience with the effects of climate change and the psychological distance associated with people''s concern for global and local impacts can influence environmental behavior. Here we surveyed farmers in a representative rural county in California''s Central Valley to examine how their intention to adopt mitigation and adaptation practices is influenced by previous climate experiences and their global and local concerns about climate change. Perceived changes in water availability had significant effects on farmers'' intention to adopt mitigation and adaptation strategies, which were mediated through global and local concerns respectively. This suggests that mitigation is largely motivated by psychologically distant concerns and beliefs about climate change, while adaptation is driven by psychologically proximate concerns for local impacts. This match between attitudes and behaviors according to the psychological distance at which they are cognitively construed indicates that policy and outreach initiatives may benefit by framing climate impacts and behavioral goals concordantly; either in a global context for mitigation or a local context for adaptation.     

An essential ligand-binding domain in the membrane receptor for retinol-binding protein revealed by large-scale mutagenesis and a human polymorphism

Plasma retinol-binding protein (RBP), the principal carrier of vitamin A in the blood, delivers vitamin A from liver, the site of storage, to distant organs that need vitamin A, such as the eye, brain, placenta, and testis. STRA6 is a high-affinity membrane receptor for RBP and mediates vitamin A uptake in these target organs. STRA6 is a 74-kDa multi-transmembrane domain protein that represents a new class of membrane transport protein. In this study, we used an unbiased strategy by analyzing >900 random mutants of STRA6 to study its structure and function, and we identified an essential RBP-binding domain in STRA6. Mutations in any of the three essential residues in this domain can almost completely abolish binding of STRA6 to RBP and its vitamin A uptake activity from holo-RBP without affecting its cell surface expression. We have also functionally characterized the mutations in human STRA6 that cause severe birth defects as well as several human polymorphisms. All STRA6 mutants associated with severe birth defects have largely abolished vitamin A uptake activity, consistent with the severe clinical phenotypes. In addition, we have identified a human polymorphism that significantly reduces the vitamin A uptake activity of STRA6. Interestingly, the residue affected by this polymorphism is located in the RBP-binding domain we identified, and the polymorphism causes decreased vitamin A uptake by reducing RBP binding. This study identifies an essential functional domain in STRA6 and a human polymorphism in this domain that leads to reduced vitamin A uptake activity.     

Productivity and grazing impact of Oikopleura dioica (Tunicata, Appendicularia) in Tokyo Bay

To estimate the productivity and grazing impact of a commonappendicularian species Oikopleura dioica in Tokyo Bay, monthlyobservations on its abundance and vertical distribution wereconducted during 2000. The abundance peaked in February andOctober, but was low during summer. Seasonal fluctuations inproductivity were similar to those of the abundance, with maximumvalues of 92, 134 and 508 mg C m^–2 day^–1 for somatic,new house and discarded house productivity in October and 206mg C m^–2 day^–1 for fecal pellet productivity inFebruary, respectively. The averaged biomass of O. dioica wasonly 2.5% of that of copepods; however, the secondary productivityof the former corresponded to 12.4% of the latter. Daily grazingimpact on particulate organic carbon ranged from 0.05% to 5%,which is close to the impact by copepods. These results implythat in Tokyo Bay, where small copepods and jellyfish are abundant,O. dioica is an important component of the ecosystem becauseit bridges between small primary producers and higher consumers.     

Interaction of nitrogen and phosphorus nutrition in determining growth

In this paper we discuss the differences and similarities in the growth response of tomato plants to N and P limitation, and to their interaction. Two detailed growth experiments, with varied N or P supply, were conducted in order to unravel the effects of N and P limitation on growth of young tomato plants (Lycopersicon esculentum Mill.). Relative growth rate (RGR) initially increased sharply with increasing plant P concentration but leveled off at higher plant P concentrations. In contrast, RGR increased gradually with increasing plant N concentration before it leveled off at higher plant N concentrations. The relationship of RGR with organic leaf N and P showed the same shape as with total N and P concentrations, respectively. The difference in response is most likely due to the different roles of N and P in the machinery of the plant's energy metabolism (e.g., photosynthesis, respiration). Plant N concentration decreased with increasing P limitation. We show that this decrease cannot be explained by a shift in dry-mass partitioning. Our results suggest that the decrease in N concentration with increasing P limitation may be mediated by a decrease in leaf cytokinin levels and is less likely due to decreased energy availability at low P conditions. Dry-mass partitioning to the roots was closely linearly related to the leaf reduced-N concentration. However, treatments that were severely P limited deviated from this relationship.     

Localization of the gene encoding insulin-degrading enzyme to human chromosome 10, bands q23----q25.

Insulin-degrading enzyme (IDE) is a cytosolic proteinase involved in the cellular processing of insulin. Using somatic cell hybrid analysis and in situ chromosomal hybridization, we have localized the gene encoding IDE to human chromosome 10, bands q23----q25. The murine Ide gene was previously mapped to Chromosome 19; together, these results suggest that the IDE gene is a member of a conserved syntenic group on human chromosome 10, bands q23----q25 and mouse Chromosome 19.