Structural and functional characterization of the extracellular domain of the human CaSR with bound Mg2+ and a tryptophan derivative.

Scaling soil respiration (R S ), the major CO 2 source to the atmosphere from terrestrial ecosystems, from chamber-based measurements to ecosystems requires studies on variations and correlations of R S from various biomes and across geographic regions. However, few studies on R S are available for Chinese temperate forest despite the importance of this forest in the national and global carbon budgets. In this study, we conducted 18-month R S measurements during 2004-2005 in six temperate forest types, representing the typical secondary forest ecosystems across various site conditions in northeastern China: Mongolian oak (Quercus mongolica Fisch.), aspen-birch (Populous davidiana Dode and Betula platyphylla Suk.), mixed deciduous (no dominant tree species), hardwood (dominated by Fraxinus mandshurica Rupr., Juglans mandshurica Maxim., and Phellodendron amurense Rupr.) forests, Korean pine (Pinus koraiensis Sieb. et Zucc.) and Dahurian larch (Larix gmelinii Rupr.) plantations. Our specific objectives were to: (1) explore relationships of R S against soil temperature and water content for the six forest ecosystems, (2) quantify annual soil surface CO 2 flux and its relations to belowground carbon storage, (3) examine seasonal variations in R S and related environmental factors, and (4) quantify among-and within-ecosystem variations in R S . The R S was positively correlated to soil temperature in all forest types, and was significantly influenced by the interactions of soil temperature and water content in the pine, larch, and mixed deciduous forests. The sensitivity of R S to soil temperature at 10 cm depth (Q 10 ) ranged from 2.61 in the oak forest to 3.75 in the aspen-birch forests. The Q 10 tended to increase with soil water content until reaching a threshold, and then decline. The annual R S for the larch, pine, hardwood, oak, mixed deciduous, and aspen-birch forests averaged 403, 514, 781, 785, 786, and 813 g C m À2 yr À1 , respectively. The annual R S of the broadleaved forests was 72% greater than that of the coniferous forests. The annual R S was positively correlated to soil organic carbon (SOC) concentration at O horizon (R 2 5 0.868) and total biomass of roots o0.5 cm in diameter (R 2 5 0.748). The coefficient of variation (CV) of R S among forest types averaged 25% across the 18-month measurements. The CV of R S within plots varied from 20% to 27%, significantly (Po0.001) greater than those among plots (9-15%), indicating the importance of the fine-scaled heterogeneity in R S . This study emphasized that variations in soil respiration and potential sampling bias should be appropriately tackled for accurate soil CO 2 flux estimates.*The regression models are of form: Ln(R S ) 5 a 1 b  T 10 1 c  W 10 1 d  T 10  W 10 , where Ln is natural logarithm; a, b, c, d are significant coefficients (a 5 0.05) (insignificant terms are not listed in the table). N, MSE, R 2 , and P stand for sample size, mean squared error, determination coefficient, and P value, respectively.

Atmospheric carbon dioxide enrichment (eCO 2) can enhance plant carbon uptake and growth 1,2,3,4,5 , thereby providing an important negative feedback to climate change by slowing the rate of increase of the atmospheric CO 2 concentration 6. While evidence gathered from young aggrading forests has generally indicated a strong CO 2 fertilization effect on biomass growth 3,4,5 , it is unclear whether mature forests respond to eCO 2 in a similar way. In mature trees and forest stands 7,8,9,10 , photosynthetic uptake has been found to increase under eCO 2 without any apparent accompanying growth response, leaving an open question about the fate of additional carbon fixed under eCO 2 4,5,7,8,9,10,11. Here, using data from the first ecosystemscale Free-Air CO 2 Enrichment (FACE) experiment in a mature forest, we constructed a comprehensive ecosystem carbon budget to track the fate of carbon as the forest responds to four years of eCO 2 exposure. We show that, although the eCO 2 treatment of ambient +150 ppm (+38%) induced a 12% (+247 g C m-2 yr-1) increase in carbon uptake through gross primary production, this additional carbon uptake did not lead to increased carbon sequestration at the ecosystem level. Instead, the majority of the extra carbon was emitted back into the atmosphere via several respiratory fluxes, with increased soil respiration alone accounting for ~50% of the total uptake surplus. Our results call into question the predominant thinking that the capacity of forests to act as carbon sinks will be generally enhanced under eCO 2 , and challenge the efficacy of climate mitigation strategies that rely on ubiquitous CO 2 fertilization as a driver of increased carbon sinks in global forests. Main text Globally, forests act as a large carbon sink, absorbing a significant portion of the anthropogenic CO 2 emissions 1,12 , an ecosystem service that has tremendous social and

Genistein, an isoflavone in soybean products, has estrogenic activity and is used as a natural substitute for estrogen replacement therapy in postmenopausal women. Genistein was also shown to decrease fat pad weight in female mice. The primary objective of this study was to determine the effect of genistein on adipose tissue apoptosis in vitro and in vivo. 3T3-L1 preadipocytes and mature adipocytes were treated with 0, 1, 10, 100, and 400 micromol/L genistein and then assayed for apoptosis, whereas only mature adipocytes were assayed for viability. Mature adipocytes treated with genistein demonstrated a dose-related increase in apoptosis. Ovariectomized female mice (9 mo old) were given 0, 150, or 1,500 mg/kg genistein in the semipurified phytoestrogen-free casein-based diet for 3 wk (n=10). After mice were killed, body composition was determined by dual-energy X-ray absorptiometry analysis, and parametrial (PM), inguinal (ING), and retroperitoneal (RP) fat pads were weighed and assayed for apoptosis (% DNA fragmentation). Genistein (1500 mg/kg) reduced food intake (FI) by 14% (P<0.01) and body weight (BW) by 9% (P<0.01). Body composition was not significantly affected, but PM and ING weights were decreased 22% (P<0.05) and 19% (P<0.07), respectively, by 1,500 mg/kg genistein. Apoptosis in ING fat was increased 290% (P<0.05) by 1,500 mg/kg genistein. These findings show that oral genistein treatment can reduce BW, mobilize body fat, and induce apoptosis of adipose tissue in ovariectomized female mice. Thus, genistein may be useful in treating or preventing increased adiposity after menopause.

During circulation in humans and natural selection to escape antibody recognition for decades, A/H3N2 influenza viruses emerged with altered receptor specificities. These viruses lost the ability to agglutinate erythrocytes critical for antigenic characterization and give low yields and acquire adaptive mutations when cultured in eggs and cells, contributing to recent vaccine challenges. Examination of receptor specificities of A/H3N2 viruses reveals that recent viruses compensated for decreased binding of the prototypic human receptor by recognizing α2,6-sialosides on extended LacNAc moieties. Erythrocyte glycomics shows an absence of extended glycans providing a rationale for lack of agglutination by recent A/H3N2 viruses. A glycan remodeling approach installing functional receptors on erythrocytes, allows antigenic characterization of recent A/H3N2 viruses confirming the cocirculation of antigenically different viruses in humans. Computational analysis of HAs in complex with sialosides having extended LacNAc moieties reveals that mutations distal to the RBD reoriented the Y159 side chain resulting in an extended receptor binding site.