A water-soluble glucan, isolated from the alkaline extract of the fruit bodies of an edible mushroom, Lentinus squarrosulus (Mont.) Singer was found to consist of (1→3,6)-linked, (1→3)-linked, (1→6)-linked, and terminal β-d-glucopyranosyl moieties in a relative proportion of approximately 1:2:1:1. This polysaccharide showed optimum activation of macrophages as well as splenocytes and thymocytes at 10 μg/mL. Structural investigation was carried out using sugar analysis, methylation analysis, periodate oxidation study, and NMR experiments (1H, 13C, DEPT-135, DQF-COSY, TOCSY, NOESY, ROESY, HMQC, and HMBC). On the basis of above-mentioned experiments, the structure of the repeating unit of the polysaccharide was established as: 相似文献
Robust estimates of CO2 budget, CO2 exchanged between the atmosphere and terrestrial biosphere, are necessary to better understand the role of the terrestrial biosphere in mitigating anthropogenic CO2 emissions. Over the past decade, this field of research has advanced through understanding of the differences and similarities of two fundamentally different approaches: “top‐down” atmospheric inversions and “bottom‐up” biosphere models. Since the first studies were undertaken, these approaches have shown an increasing level of agreement, but disagreements in some regions still persist, in part because they do not estimate the same quantity of atmosphere–biosphere CO2 exchange. Here, we conducted a thorough comparison of CO2 budgets at multiple scales and from multiple methods to assess the current state of the science in estimating CO2 budgets. Our set of atmospheric inversions and biosphere models, which were adjusted for a consistent flux definition, showed a high level of agreement for global and hemispheric CO2 budgets in the 2000s. Regionally, improved agreement in CO2 budgets was notable for North America and Southeast Asia. However, large gaps between the two methods remained in East Asia and South America. In other regions, Europe, boreal Asia, Africa, South Asia, and Oceania, it was difficult to determine whether those regions act as a net sink or source because of the large spread in estimates from atmospheric inversions. These results highlight two research directions to improve the robustness of CO2 budgets: (a) to increase representation of processes in biosphere models that could contribute to fill the budget gaps, such as forest regrowth and forest degradation; and (b) to reduce sink–source compensation between regions (dipoles) in atmospheric inversion so that their estimates become more comparable. Advancements on both research areas will increase the level of agreement between the top‐down and bottom‐up approaches and yield more robust knowledge of regional CO2 budgets. 相似文献
The selective pressures leading to the evolution of Sexual Size Dimorphism (SSD) have been well studied in many organisms, yet, the underlying developmental mechanisms are poorly understood. By generating a complete growth profile by sex in Drosophila melanogaster, we describe the sex-specific pattern of growth responsible for SSD. Growth rate and critical size for pupariation significantly contributed to adult SSD, whereas duration of growth did not. Surprisingly, SSD at peak larval mass was twice that of the uneclosed adult SSD with weight loss between peak larval mass and pupariation playing an important role in generating the final SSD. Our finding that weight loss is an important regulator of SSD adds additional complexity to our understanding of how body size is regulated in different sexes. Collectively, these data allow for the elucidation of the molecular-genetic mechanisms that generate SSD, an important component of understanding how SSD evolves. 相似文献
Soil aggregates govern soil organic carbon (SOC) sequestration. But, sparse understanding about the process leads to inaccuracy in predicting potential of soil to stabilize C in warming world. We appraised effects of 43 years of fertilization on relative temperature sensitivity of SOC decomposition (Q10) in soil aggregates to know whether SOC quality or quantity governs Q10. Treatments were: fallow, control, 100% recommended dose of nitrogen (N), N and phosphorus (NP), N, P and potassium (NPK), and NPK + farmyard manure (FYM) (NPK + FYM). Macroaggregates, microaggregates and silt + clay (s + c) fractions were incubated for 16 weeks at 25, 35 and 45 °C, SOC quality (R0) and Q10 were computed. SOC mineralization from macro- and micro- aggregates were 34 and 28% higher than s + c across the treatments. The s + c fraction of NPK + FYM had ~ 41, 40 and 24% higher C decay rate than NPK plots at 25, 35 and 45 °C, respectively. For s + c fraction Q10 increased over other aggregates. Mean Q10 of s + c fraction was ~ 18.3 and 17.5% higher than macro and micro-aggregate-C, respectively. R0 was the lowest for NPK + FYM, suggesting long-term manuring with balanced NPK significantly enhance recalcitrance of C. We observed Q10 of macroaggregates and s + c fraction is controlled by C quality but C quantity governs Q10 of microaggregates in Vertisol. Specifically, microaggregates of NPK + FYM were more temperature sensitive, and could be vulnerable to C loss. Hence, practices facilitating microaggregate formation should be avoided. Thus, we recommend manure application for facilitating C sequestration.
Rice grain size and weight are major determinants of grain quality and yield and so have been under rigorous selection since domestication. However, the genetic basis for contrasting grain size/weight trait among Indian germplasms and their association with domestication‐driven evolution is not well understood. In this study, two long (LGG) and two short grain (SGG) genotypes were resequenced. LGG (LGR and PB 1121) differentiated from SGG (Sonasal and Bindli) by 504 439 single nucleotide polymorphisms (SNPs) and 78 166 insertion‐and‐deletion polymorphisms. The LRK gene cluster was different and a truncation mutation in the LRK8 kinase domain was associated with LGG. Phylogeny with 3000 diverse rice accessions revealed that the four sequenced genotypes belonged to the japonica group and were at the edge of the clades indicating them to be the potential source of genetic diversity available in Indian rice germplasm. Six SNPs were significantly associated with grain size/weight and the top four of these could be validated in mapping a population, suggesting this study as a valuable resource for high‐throughput genotyping. A contiguous long low‐diversity region (LDR) of approximately 6 Mb carrying a major grain weight quantitative trait loci (harbouring OsTOR gene) was identified on Chromosome 5. This LDR was identified as an evolutionary important site with significant positive selection and multiple selection sweeps, and showed association with many domestication‐related traits, including grain size/weight. The aus population retained more allelic variations in the LDR than the japonica and indica populations, suggesting it to be one of the divergence loci. All the data and analyses can be accessed from the RiceSzWtBase database. 相似文献
Reactions of 2-(arylazo)aniline, HL (H represents the dissociable protons upon orthometallation and HL is p-RC6H4NNC6H4-NH2; RH for HL1; CH3 for HL2 and Cl for HL3) with IrCl3 in methanol afforded orthometallated complexes of composition (L)(HL)IrCl2 (2) and (L)(MeOH)IrCl2 (3), respectively. Complex (L)(MeOH)IrCl2 (3) converted into (L)(CH3CN)IrCl2 (4) upon refluxing in acetonitrile. The X-ray structure of the complexes (L1)(HL1)IrCl2 (2a) and (L3)(CH3CN)IrCl2 (4c) have been determined and characterized unequivocally. The anionic L− binds the metal in tridentate (C, N, N) manner for all the complexes. 相似文献
In vitro antibacterial activities of acetone, ethanol, methanol and water extracts of leaves and bark of Croton roxburghii L. studied against ten human pathogenic bacterial strains showed significantly higher activity in acetone extract and least
activity in case of aqueous. Minimal inhibitory concentration (MIC) values of all extracts ranged between 0.62 and 10 mg/ml,
while minimal bactericidal concentration (MBC) values ranged from 1.25 to values greater than 10 mg/ml. The antioxidant assays
viz. DPPH, hydrogen peroxide scavenging, iron reducing and iron chelating assays along with total phenol and ascorbic acid
content were carried out with aqueous extracts of leaves and bark. While the total phenol contents in leaves and bark extracts
were 0.766 ± 0.014 and 0.735 ± 0.028% respectively their ascorbic acid contents were found to be 0.252 ± 0.019 and 0.431 ± 0.013%
respectively. DPPH activities in both (leaves and bark) extracts increased with the increase in concentrations. Iron chelating
capacity of leaves extract is significantly higher than that of the bark. Leaves extract showed an increase in percentage
of scavenging property with the increase in concentrations. Plant extracts showed low amount of iron reducing property at
all concentrations. Hydrogen peroxide scavenging properties of bark was low than that of the leaves. 相似文献
Multi-electron NAtrium SuperIonic CONductor (NASICON)-Nb2(PO4)3 (N0NbP) is an attractive Na-ion battery anode, owing to its low intercalation voltage (1.4 V vs Na+/Na0) and high capacity (≈150 mAh g−1). However, it suffers from poor capacity retention due to structural degradation. To overcome this issue, extra Na+ ions are introduced at the Na(1) sites, via V3+ substitution, which can act as stabilizing agents to hold lantern units together during cycling, producing NASICON-Na1.5V0.5Nb1.5(PO4)3 (N1.5VNbP). The N1.5VNbP anode exhibits reversible capacities of ≈140 mAh g−1 at 1.4 V versus Na+/Na0 through Nb5+/Nb4+/Nb3+ and V3+/V2+ redox activities. The extra Na+ ions in the framework forms a complete solid-solution during Na (de)intercalation and enhances sodium diffusivity, in agreement with first-principles calculations. Further, N1.5VNbP demonstrates extraordinary cycling (89% capacity retention at 5C after 500 cycles) and rate performances (105 mAh g−1 at 5C). Upon pairing the N1.5VNbP anode with the NASICON-Na3V2(PO4)3 cathode, the full Na-ion cell delivers a remarkable energy density of 98 Wh kg−1 (based on the mass of anode and cathode) and retains 80% of its capacity at 5C rate over 1000 cycles. The study opens new possibilities for enhancing the electrochemical performance of NASICON anodes via chemical and structural modulations. 相似文献