黄龙山森林植被地上碳储量时空变化及驱动力

快速准确地估计植被地上碳储量及其动态变化,对评估森林固碳能力具有重要意义。以陕西省黄龙林区森林为研究对象,基于样地实测和卫星遥感数据,建立黄龙山林区植被地上碳储量模型,实现研究区2000-2021年长时间序列的森林植被地上碳储量的反演及时空分异研究。结果表明：（1）黄龙山森林植被地上碳储量平均值总体呈波动上升趋势,碳储量高于全省平均水平。（2）研究区东部、南部、中部及西北部是植被地上碳储量高值分布地区,且呈增加趋势;而东北部、西部和西南部植被地上碳储量较低,且呈减少趋势,研究区22年间森林植被地上部分固碳量增加,生产力提升。（3）年均温、年蒸散发量、年降水量和海拔是2000-2021年影响研究区森林植被地上碳储量空间分异主要因素;任意两个因子间的交互作用对黄龙山森林地上碳储量影响都大于单个因子,表明黄龙山森林植被地上碳储量在不同时间的空间分布受多种因素共同作用。年降水量对其空间分布影响逐渐减小,森林稳定性提高。研究在信息有限的基础上提出了快速估算地区植被地上碳储量的方法,了解了地区森林植被地上碳储量时空分异情况及其驱动因素,为掌握地区植被地上碳储量信息、评估森林固碳能力提供了重要依据。     

宁夏不同地区盐碱化土壤细菌群落多样性分布特征及其影响因子

为了解宁夏不同地区盐碱化土壤细菌群落多样性的分布特征及其关键影响因子,选择贺兰县红星村、惠农县黄渠拐子、燕子墩、庙台、平罗县银星村、分水闸、侯家梁、西大滩为研究样点,采集宁夏地区8个典型盐碱化土壤样品,0—2 cm和2—25 cm土层,共48份。利用Illumina Hiseq高通量测序技术解析不同采样点土壤细菌群落结构的特征,同时分析了土壤理化因子与细菌群落结构的关系。试验结果表明:变形菌门、拟杆菌门和放线菌门为8个采样点土壤细菌群落的优势种类。其中,变形菌门占总量的24.69%—56.44%;γ-变形菌纲相对丰度在燕子墩土壤中显著高于其他样点(P<0.05)。0—2 cm土层,变形菌门相对丰度在燕子墩、红星村和分水闸这3个样点较高;拟杆菌门的相对丰度在分水闸样点土壤中最高;2—25 cm土层,变形菌门与表层土具有相同趋势;放线菌门的相对丰度在西大滩样点土壤中最高。在属水平,芽孢杆菌属是所有样点的优势属种。α多样性指数结果显示:燕子墩的土壤细菌群落多样性和丰富度都显著低于其他样点。土壤理化性质测定结果表明:在0—2 cm,全氮、有机碳、碱解氮、速效钾在黄渠拐子土壤中含量最高;含...     

ISGylation of EMD promotes its interaction with PDHA to inhibit aerobic oxidation in lung adenocarcinoma

Abnormal nuclear structure caused by dysregulation of skeletal proteins is a common phenomenon in tumour cells. However, how skeletal proteins promote tumorigenesis remains uncovered. Here, we revealed the mechanism by which skeletal protein Emerin (EMD) promoted glucose metabolism to induce lung adenocarcinoma (LUAD). Firstly, we identified that EMD was highly expressed and promoted the malignant phenotypes in LUAD. The high expression of EMD might be due to its low level of ubiquitination. Additionally, the ISGylation at lysine 37 of EMD inhibited lysine 36 ubiquitination and upregulated EMD stability. We further explored that EMD could inhibit aerobic oxidation and stimulate glycolysis. Mechanistically, via its β‐catenin interaction domain, EMD bound with PDHA, stimulated serine 293 and 300 phosphorylation and inhibited PDHA expression, facilitated glycolysis of glucose that should enter the aerobic oxidation pathway, and EMD ISGylation was essential for EMD‐PDHA interaction. In clinical LUAD specimens, EMD was negatively associated with PDHA, while positively associated with EMD ISGylation, tumour stage and diameter. In LUAD with higher glucose level, EMD expression and ISGylation were higher. Collectively, EMD was a stimulator for LUAD by inhibiting aerobic oxidation via interacting with PDHA. Restricting cancer‐promoting role of EMD might be helpful for LUAD treatment.     

Suspension culture of gametophytes of transgenic kelp in a photobioreactor

Transgenic Laminaria japonica gametophytes producing a recombinant tissue-type plasminogen activator (rtPA) protein, which is an effective third-generation thrombolytic agent for acute myocardial infarction (AMI), were cultured in an illuminated bubble column bioreactor. A maximum final dry cell weight of 1120 mg l⁻¹ was obtained in batch culture with an initial dry cell weight of 126 mg l⁻¹ and with aeration rate of 1.2 l air min⁻¹ l⁻¹ culture, nitrate at 1.5 mM and phosphate at 0.17 mM. The yield of rtPA was 56 μg g⁻¹ dry cell wt. This is the first report regarding cultivation of a transgenic macroalga in a bioreactor.Revisions requested 27 January 2005 and 14 April 2005; Revisions received 6 April 2005 and 17 May 2005     

Optimal Light Regime for the Cultivation of Transgenic Laminaria japonica Gametophytes in a Bubble-column Bioreactor

Fluctuating light intensity had a more significant impact on growth of gametophytes of transgenic Laminaria japonica in a 2500 ml bubble-column bioreactor than constant light intensity. A fluctuating light intensity between 10 and 110 μE m⁻² s⁻¹, with a photoperiod of 14 h:10 h light:dark, was the best regime for growth giving 1430 mg biomass l⁻¹.     

Synthesis and antiviral activity against Coxsackie virus B3 of some novel benzimidazole derivatives

Some benzimidazole derivatives were synthesized and evaluated for their antiviral properties. Compounds 20 and 21 showed potent selective activity against Coxsackie virus B(3) in VERO cells. Some structure-activity relationships were discussed.     

Which root traits determine nitrogen uptake by alpine plant species on the Tibetan Plateau?

Background and aims

Nitrogen (N) is one of the most important limiting factors influencing plant growth and reproduction in alpine and tundra ecosystems. However, in situ observations of the effects of root traits on N absorption by alpine plant species are still lacking.

Methods

We investigated the rates of N uptake and the effect of root characteristics in ten common herbaceous alpine plant species using a ¹⁵N isotope tracer technique and the root systems of plants growing in a semi-arid steppe environment on the Tibetan Plateau. Our objective was to determine the root traits (root biomass, volume, surface area, average diameter, length, specific root length and specific root area) that make the largest contribution to the total uptake of N (¹⁵N–NO₃ ^?, ¹⁵N–NH₄ ⁺ or ¹⁵N–glycine) by alpine plant species.

Results

Monocotyledonous species had higher absorption rates for ¹⁵N–NH₄ ⁺, ¹⁵N–NO₃ ^?, ¹⁵N–glycine and total ¹⁵N than dicotyledonous species (P < 0.05). The root biomass, volume, surface area and average diameter were negatively correlated with the absorption capacity for ¹⁵N–NH₄ ⁺, ¹⁵N–NO₃ ^? and total ¹⁵N across the ten alpine plant species. However, the specific root length and the specific root area had significantly positive effects on the uptake of N.

Conclusions

In contrast with traditional views on the uptake of N, the N uptake rate was not improved by a larger root volume or root surface area for these alpine plant species in a high-altitude ecosystem. Root morphological traits had greater impacts on N absorption than traits related to the root system size in alpine herbaceous plants.