Protein Profiling from Hormone-Induced Tetraploid Roots in Platycodon grandiflorum

Journal of Crop Science and Biotechnology - The root of Platycodon grandiflorum is used as traditional oriental medicine in Asian countries since ancient times to treat bronchitis, tonsillitis,...     

利用数学曲面进行土地整理设计

土地整理是增加耕地面积,提高土地质量,实现农村经济社会发展的重要举措;同时地面整理也是防止土壤侵蚀的重要措施之一。土地整理是一个需要多项技术支持的综合工程。与水田相比,耕地的地面形状比较复杂,因此地块设计的地形数据和设计方法也繁多。耕作田块是耕作的基本单元,田块设计包括田块的方向、形状、规模等因素,在设计当中要采取智能化、简单化、精确化的算法,以便适应多种多样的地形以及地质条件。该文在田块整理设计中利用一般n次曲面方程的求解算法提出了适应各种地形条件和整理对象要求的田块整理设计面确定方法。      

Cause and effect in biology revisited: is Mayr's proximate-ultimate dichotomy still useful?

Fifty years ago, Ernst Mayr published a hugely influential paper on the nature of causation in biology, in which he distinguished between proximate and ultimate causes. Mayr equated proximate causation with immediate factors (for example, physiology) and ultimate causation with evolutionary explanations (for example, natural selection). He argued that proximate and ultimate causes addressed different questions and were not alternatives. Mayr's account of causation remains widely accepted today, with both positive and negative ramifications. Several current debates in biology (for example, over evolution and development, niche construction, cooperation, and the evolution of language) are linked by a common axis of acceptance/rejection of Mayr's model of causation. We argue that Mayr's formulation has acted to stabilize the dominant evolutionary paradigm against change but may now hamper progress in the biological sciences.     

Solvated electrons in high-temperature melts and glasses of the room-temperature stable electride [Ca₂₄Al₂₈O₆₄]⁴⁺·4e⁻

Solvated electrons in alkali metal-ammonia solutions have attracted attention as a prototype electronic conductor and chemical reducing agent for over a century. However, solvated electrons have not been realized in a high-temperature melt or glass of an oxide system to date. We demonstrated the formation of persistent solvated electrons in both a high-temperature melt and its glass by using the thermally stable electride [Ca(24)Al(28)O(64)](4+)·4e(-) (C12A7:e(-)) and controlling the partial pressure of oxygen. The electrical and structural properties of the resulting melt and glass differ from those of the conventional C12A7:O(2-) oxide, exhibiting metallic and hopping conduction, respectively, and a glass transition temperature that is ~160 kelvin lower than that of C12A7:O(2-) glass. Solvated electrons reside in cage structures in C12A7:e(-) and form a diamagnetic paired state.     

Imaging of transient structures using nanosecond in situ TEM

The microstructure and properties of a material depend on dynamic processes such as defect motion, nucleation and growth, and phase transitions. Transmission electron microscopy (TEM) can spatially resolve these nanoscale phenomena but lacks the time resolution for direct observation. We used a photoemitted electron pulse to probe dynamic events with "snapshot" diffraction and imaging at 15-nanosecond resolution inside of a dynamic TEM. With the use of this capability, the moving reaction front of reactive nanolaminates is observed in situ. Time-resolved images and diffraction show a transient cellular morphology in a dynamically mixing, self-propagating reaction front, revealing brief phase separation during cooling, and thus provide insights into the mechanisms driving the self-propagating high-temperature synthesis.     

Evidence for antibody-catalyzed ozone formation in bacterial killing and inflammation

Recently, we showed that antibodies catalyze the generation of hydrogen peroxide (H2O2) from singlet molecular oxygen (1O2*) and water. Here, we show that this process can lead to efficient killing of bacteria, regardless of the antigen specificity of the antibody. H2O2 production by antibodies alone was found to be not sufficient for bacterial killing. Our studies suggested that the antibody-catalyzed water-oxidation pathway produced an additional molecular species with a chemical signature similar to that of ozone. This species is also generated during the oxidative burst of activated human neutrophils and during inflammation. These observations suggest that alternative pathways may exist for biological killing of bacteria that are mediated by potent oxidants previously unknown to biology.     

Examining talent attraction and retention in small and medium-sized cities: Where do universities fit in?

As universities have become more integrated into their communities and regions, their host cities have become locations of choice for the highly educated facilitating increased innovation and productivity rates in several locales. Recent transitions toward knowledge-driven economies have also intensified growing geographic divides along the lines of education and raised concerns about the possibility of brain drain in a growing number of cities/regions. This study examines the changing geography of highly educated individuals (2000–2017) with a focus on small and medium-sized U.S. metropolitan areas with and without research universities. Results indicate the continuing trend of divergence among regions, but research universities are found to complement (the lack of) talent agglomeration and generate spatial spillovers beyond the county boundaries.     

Degradation of outer membrane protein A in Escherichia coli killing by neutrophil elastase

In determining the mechanism of neutrophil elastase (NE)-mediated killing of Escherichia coli, we found that NE degraded outer membrane protein A (OmpA), localized on the surface of Gram-negative bacteria. NE killed wild-type, but not OmpA-deficient, E. coli. Also, whereas NE-deficient mice had impaired survival in response to E. coli sepsis, as compared to wild-type mice, the presence or absence of NE had no influence on survival in response to sepsis that had been induced with OmpA-deficient E. coli. These findings define a mechanism of nonoxidative bacterial killing by NE and point to OmpA as a bacterial target in host defense.     

Positional cloning of the human quantitative trait locus underlying taste sensitivity to phenylthiocarbamide

The ability to taste the substance phenylthiocarbamide (PTC) has been widely used for genetic and anthropological studies, but genetic studies have produced conflicting results and demonstrated complex inheritance for this trait. We have identified a small region on chromosome 7q that shows strong linkage disequilibrium between single-nucleotide polymorphism (SNP) markers and PTC taste sensitivity in unrelated subjects. This region contains a single gene that encodes a member of the TAS2R bitter taste receptor family. We identified three coding SNPs giving rise to five haplotypes in this gene worldwide. These haplotypes completely explain the bimodal distribution of PTC taste sensitivity, thus accounting for the inheritance of the classically defined taste insensitivity and for 55 to 85% of the variance in PTC sensitivity. Distinct phenotypes were associated with specific haplotypes, which demonstrates that this gene has a direct influence on PTC taste sensitivity and that sequence variants at different sites interact with each other within the encoded gene product.     

Microorganism repair after UV-disinfection of secondary-level effluent for agricultural irrigation

A pilot study of microorganism repair after UV disinfection was performed for agricultural reuse of secondary-level effluent in paddy rice fields in Korea. Effluent from the bio-filter of a 16-unit apartment was used in a flow-through type UV-disinfection system. The average concentration of suspended solids (SS) and biochemical oxygen demand (BOD) were 3.4 and 5.9 mg L⁻¹, respectively. The mean total coliform level was in the range of 1.5 × 10⁴ MPN 100 mL⁻¹. Photoreactivation and dark repair were apparent at a low UV dose (6 mW s cm⁻²). In low-dose UV disinfection, microorganisms increased within 12 h by approximately 5 and 1% due to photoreactivation and dark repair, respectively. This increase was not significant at a high UV dose (16 mW s cm⁻²). The repaired microorganisms were further inactivated, rather than reactivated, by solar irradiation, and numbers decreased to non-detectible levels after 4 h of exposure to solar irradiation. Based on UV disinfection and repair studies, a UV dose of 30 mW s cm⁻² is recommended as sufficient to produce reclaimed water virtually free of pathogens and may be adequate for disinfection of secondary effluent for agricultural irrigation in paddy rice culture.