糞生菌之生理生態及其拮抗作用之研究

[[abstract]]實驗所用之菌種採自台北木柵動物園飼養兔所分分離而得，經鑑定共獲１２種糞生菌 的純培養菌株。觀察分布情形發現，各糞生菌其消長現象雖不明顯，但其殘存時間各 不同，另因季節不同，各菌屬分布也有差異，其中以糞盤菌屬（ASCOBOLUS SPP.）及 糞殼菌（SORDARIA SPP. ）分布頻度最低，自然條件下糞物分解以在培養第３０天分 解率達最高。 生理試驗結果顯示，子實體形成有一定時間與孢子萌芽時間及生長速率無一定相關； 此類糞生菌最佳之生長條件為：ｐＨ偏鹼性，一般在６．４－７．４之間；溫度在２ ２－３１℃之間；並且對兩者耐性範圍廣泛；基質含水量在１１－１９（-bar）為最 適生長，但依溫度不同而有差異。對不同基質水解情形而言，各糞生菌對尿素，脂質 之水解能力達１００％，不同醣類之水解亦達７０－８０％，而以對蛋白質之水解能 力為最弱僅達３０％。 單種接種對於糞物之分解率高於混合接種者，但差異性不大，對峙培養發現各菌種間 其拮抗能力各有不同，但與其生長速率無關，七種試驗菌種中，球毛殼菌（CHAETOMI UM GLOBOSUM ）的拮抗能力最大，球毛殼菌與五谷麻孢殼菌（GELASINOSPORA CEREAL IS）對峙培養產生之拮抗色素最明顯，此兩種拮抗菌種對營養需求極為近似。拮抗作 用之產生導致菌絲纏繞，原生質流失，菌絲壁色素化，以及氧化酵素活性之改變。天 間冬胺酸（ASPARAGINE）是最好的黑色素（MELANIN ）誘導氮原，將此兩種菌混合培 養後，測得酚氧化酵素活性較單種培養為高，並且在培養末期愈明顯；葡萄糖濃度在 ０．１％時酵素活性較其它最高。

Flavonoids from the halophyte Apocynum venetum and their antifouling activities against marine biofilm-derived bacteria

Eleven flavonoids were isolated from the leaves of the halophyte Apocynum venetum. Among them, the isolation of plumbocatechin A (1), 8-O-methylretusin (2) and kaempferol 3-O-(6-O-acetyl)--d-galactopyranoside (7) was reported for the first time from this plant. Their structures were identified by using spectral methods, including 2D NMR experiments, and confirmed by comparing with the literature data. In addition, the antifouling activities of these compounds against the marine fouling bacteria, Bacillus thuringiensis, Pseudoalteromonas elyakovii and Pseudomonas aeruginosa, have been evaluated in this article.Eleven flavonoids were isolated from the leaves of the halophyte Apocynum venetum. Among them, the isolation of plumbocatechin A (1), 8-O-methylretusin (2) and kaempferol 3-O-(6-O-acetyl)--d-galactopyranoside (7) was reported for the first time from this plant. Their structures were identified by using spectral methods, including 2D NMR experiments, and confirmed by comparing with the literature data. In addition, the antifouling activities of these compounds against the marine fouling bacteria, Bacillus thuringiensis, Pseudoalteromonas elyakovii and Pseudomonas aeruginosa, have been evaluated in this article

Ecoenzymatic stoichiometry and microbial nutrient limitation in rhizosphere soil in the arid area of the northern Loess Plateau, China

Arid ecosystems are characterized as having stressful conditions of low energy and nutrient availability for soil microorganisms and vegetation. The rhizosphere serves as the one of most active microorganism habitats, however, the general understanding of the ecoenzymatic stoichiometry (exoenzymes) and microbial nutrient acquisition in rhizosphere soil is limited. Here, we investigated the vegetation communities and determined the soil physicochemical properties, microbial biomass, and enzymatic activities in rhizosphere under different vegetation and soil types in the arid area of the northern Loess Plateau. Type II standard major axis (SMA) regression analysis showed that the plants played a more important role than soil properties in determining ecoenzymatic stoichiometry. Linear regression analysis displayed a microbial stoichiometric homeostasis (community-level) in rhizosphere. The Threshold Elemental Ratio (TER) revealed that the microbial nutrient metabolisms of rhizosphere were co-limited by N and P in the A. ordosica and A. cristatum communities of loess, and A. cristatum communities of feldspathic sandstone weathered soil. Binding spatial ordination analysis (RDA and CCA) demonstrated that soil physical properties (e.g., soil moisture, silt and clay contents) have more contribution to ecoenzymatic stoichiometry than the other investigated soil parameters, whereas soil nutrients (e.g., total organic carbon, nitrogen, and phosphorus) predominantly controlled microbial nutrient ratios. Therefore, the ecoenzymatic stoichiometry in rhizosphere is greatly regulated by plants and soil physical properties. The microbial N and P are co-limited under Gramineae plant in loess and feldspathic sandstone weathered soil regions. Meanwhile, the microbial nutrient limitation is mainly affected by soil nutrient supply. These findings could be crucial for illuminating rhizosphere microbial metabolism and revealing the nutrient cycling of root-soil interface under arid and oligotrophic ecosystems

The on-orbit calibration of DArk Matter Particle Explorer

The DArk Matter Particle Explorer (DAMPE), a satellite-based cosmic ray and gamma-ray detector, was launched on December 17, 2015, and began its on-orbit operation on December 24, 2015. In this work we document the on-orbit calibration procedures used by DAMPE and report the calibration results of the Plastic Scintillator strip Detector (PSD), the Silicon-Tungsten tracKer-converter (STK), the BGO imaging calorimeter (BGO), and the Neutron Detector (NUD). The results are obtained using Galactic cosmic rays, bright known GeV gamma-ray sources, and charge injection into the front-end electronics of each sub-detector. The determination of the boundary of the South Atlantic Anomaly (SAA), the measurement of the live time, and the alignments of the detectors are also introduced. The calibration results demonstrate the stability of the detectors in almost two years of the on-orbit operation

The on-orbit calibration of DArk Matter Particle Explorer

The DArk Matter Particle Explorer (DAMPE), a satellite-based cosmic ray and gamma-ray detector, was launched on December 17, 2015, and began its on-orbit operation on December 24, 2015. In this work we document the on-orbit calibration procedures used by DAMPE and report the calibration results of the Plastic Scintillator strip Detector (PSD), the Silicon-Tungsten tracKer-converter (STK), the BGO imaging calorimeter (BGO), and the Neutron Detector (NUD). The results are obtained using Galactic cosmic rays, bright known GeV gamma-ray sources, and charge injection into the front-end electronics of each sub-detector. The determination of the boundary of the South Atlantic Anomaly (SAA), the measurement of the live time, and the alignments of the detectors are also introduced. The calibration results demonstrate the stability of the detectors in almost two years of the on-orbit operation

The on-orbit calibration of DArk Matter Particle Explorer

The DArk Matter Particle Explorer (DAMPE), a satellite-based cosmic ray and gamma-ray detector, was launched on December 17, 2015, and began its on-orbit operation on December 24, 2015. In this work we document the on-orbit calibration procedures used by DAMPE and report the calibration results of the Plastic Scintillator strip Detector (PSD), the Silicon-Tungsten tracKer-converter (STK), the BGO imaging calorimeter (BGO), and the Neutron Detector (NUD). The results are obtained using Galactic cosmic rays, bright known GeV gamma-ray sources, and charge injection into the front-end electronics of each sub-detector. The determination of the boundary of the South Atlantic Anomaly (SAA), the measurement of the live time, and the alignments of the detectors are also introduced. The calibration results demonstrate the stability of the detectors in almost two years of the on-orbit operation