溶液流动对等电溶菌酶晶体生长的影响

本文对等温自由生长和强制性溶液生长的等电溶菌酶的晶体形态进行了研究,发现这些形态变化与溶液相的流动密切相关,指出生物晶体生长停止是由于生长晶体周围的溶质贫乏造成的;通过某些手段减薄或消除这一溶质贫乏区,就可以保证晶体的持续生长。本文的研究对改善大尺寸晶体的生长提供了一条途径。     

Decomposition of different root branch orders and its dominant controlling factors in four temperate tree species北大核心CSCD

Aims Fine root decomposition is the major pathway of carbon and nutrient input to the soil in forest ecosystems. However, the patterns and controlling factors of the decomposition of these roots, especially the finest roots, are poorly understood. Methods Using a root branch-order classification, we separated the first four orders of fine root systems of Pinus koraiensis, Larix gmelinii, Fraxinus mandschurica and Betula platyphylla into two classes: first- and second-order roots combined into lower-order; third- and fourth-order roots combined into higher-order. We conducted a four-year field litterbag study on decomposition of these four root orders of four temperate tree species in northeast China. Important findings The results showed that the lower-order and higher-order roots had a decomposition rate constant of 0.342 and 0.461 for Pinus koraiensis, 0.304 and 0.436 for Larix gmelinii, 0.450 and 0.555 for Fraxinus mandschurica, and 0.441 and 0.579 for Betula platyphylla, respectively. We observed slower decay rates in lower-order than in higher-order roots in all four studied tree species. The root decay constants (k) was significantly correlated with both acid-unhydrolyzable fraction (AUF) and total non-structural carbohydrate (TNC). We concluded that slow decomposition of lower-order roots was mainly driven by their high AUF and low TNC concentrations. © Chinese Journal of Plant Ecology.     

A Multifunctional Integrated Design of Simultaneous Unity Absorption and Polarization Conversion

Plasmonics - Herein, an integrated multifunctional design for simultaneous perfect absorption and polarization conversion is proposed that worked in the Ku band: the proposed structure consisted of...     

Allotransplantation of adult spinal cord tissues after complete transected spinal cord injury: Long-term survival and functional recovery in canines

Science China Life Sciences - Spinal cord injury (SCI), especially complete transected SCI, leads to loss of cells and extracellular matrix and functional impairments. In a previous study, we...     

Deficiency of Macf1 in osterix expressing cells decreases bone formation by Bmp2/Smad/Runx2 pathway

Microtubule actin cross‐linking factor 1 (Macf1) is a spectraplakin family member known to regulate cytoskeletal dynamics, cell migration, neuronal growth and cell signal transduction. We previously demonstrated that knockdown of Macf1 inhibited the differentiation of MC3T3‐E1 cell line. However, whether Macf1 could regulate bone formation in vivo is unclear. To study the function and mechanism of Macf1 in bone formation and osteogenic differentiation, we established osteoblast‐specific Osterix (Osx) promoter‐driven Macf1 conditional knockout mice (Macf1^f/fOsx‐Cre). The Macf1^f/fOsx‐Cre mice displayed delayed ossification and decreased bone mass. Morphological and mechanical studies showed deteriorated trabecular microarchitecture and impaired biomechanical strength of femur in Macf1^f/fOsx‐Cre mice. In addition, the differentiation of primary osteoblasts isolated from calvaria was inhibited in Macf1^f/fOsx‐Cre mice. Deficiency of Macf1 in primary osteoblasts inhibited the expression of osteogenic marker genes (Col1, Runx2 and Alp) and the number of mineralized nodules. Furthermore, deficiency of Macf1 attenuated Bmp2/Smad/Runx2 signalling in primary osteoblasts of Macf1^f/fOsx‐Cre mice. Together, these results indicated that Macf1 plays a significant role in bone formation and osteoblast differentiation by regulating Bmp2/Smad/Runx2 pathway, suggesting that Macf1 might be a therapeutic target for bone disease.     

MicroRNA‐29b‐3p suppresses oral squamous cell carcinoma cell migration and invasion via IL32/AKT signalling pathway

Oral squamous cell carcinoma (OSCC) is aggressive accompanied with poor prognosis. We previously isolated the most invasive cells resembling the invasive tumour front by microfluidic technology and explored their differentially expressed microRNAs (miRNAs) in our previous work. Here, we verified the miR‐29b‐3p as a guarder that suppressed migration and invasion of OSCC cells and was down‐regulated in the most invasive cells. Besides that, the invasion suppression role of miR‐29b‐3p was achieved through the IL32/AKT pathway. Thus, miR‐29b‐3p and IL32 might serve as therapeutic targets for blocking the progression and improving the outcome of OSCC.     

Leaf morphology shift linked to climate change

Climate change is driving adaptive shifts within species, but research on plants has been focused on phenology. Leaf morphology has demonstrated links with climate and varies within species along climate gradients. We predicted that, given within-species variation along a climate gradient, a morphological shift should have occurred over time due to climate change. We tested this prediction, taking advantage of latitudinal and altitudinal variations within the Adelaide Geosyncline region, South Australia, historical herbarium specimens (n = 255) and field sampling (n = 274). Leaf width in the study taxon, Dodonaea viscosa subsp. angustissima, was negatively correlated with latitude regionally, and leaf area was negatively correlated with altitude locally. Analysis of herbarium specimens revealed a 2 mm decrease in leaf width (total range 1-9 mm) over 127 years across the region. The results are consistent with a morphological response to contemporary climate change. We conclude that leaf width is linked to maximum temperature regionally (latitude gradient) and leaf area to minimum temperature locally (altitude gradient). These data indicate a morphological shift consistent with a direct response to climate change and could inform provenance selection for restoration with further investigation of the genetic basis and adaptive significance of observed variation.     

中国兰科禾叶兰属一新记录种——扁茎禾叶兰

报道了中国兰科植物一新记录种,扁茎禾叶兰Agrostophyllum planicaule(Wall.ex Lindl.)Rchb.f..本种主要特点是茎扁平,柱头基部有2个牛角状突起,可与本属其他种明显区分开.     

UPLC-UV法测定不同产地青蒿中青蒿素的含量

目的:建立快速简便检测青蒿素的超高效液相-紫外(UPLC-UV)法,并对不同产地青蒿中青蒿素的含量进行检测。方法:色谱柱Agilent Eclipse Plus C18(2.1 mm×50 mm,1.8μm),流动相乙腈/水(45/55),流速1.0mL/min,柱温28℃,波长200 nm。结果:该方法对青蒿素的分离度较好,保留时间缩短为1.5 min。并且,整个分析过程可以在2 min内完成。线性范围0.101 17～10.117μg,进样量与峰面积线性相关,A=109.4C+6.7026,R2=0.9 993(n=9),加样回收率为99.3%(RSD=2.6%,n=6)。结论:UPLC-UV法分析时间短、样品前处理简单、精密度、稳定性、加样回收率等符合分析检测要求,对于青蒿中青蒿素的含量能进行快速准确的分析。