白腐乳发酵过程中细菌群落演替规律研究

为解析白腐乳发酵过程中细菌的多样性,应用高通量测序和培养组学相结合的方法分析了前酵和后熟过程中细菌的变化规律,通过高通量测序分析白腐乳发酵过程中细菌16S rDNA V3-V4区基因序列。结果表明,白腐乳从前酵到后熟过程中细菌群落有较大变化,豆腐坯中的优势菌为乳杆菌（Lactobacillus）,毛坯中的优势菌为不动杆菌（Acinetobacter）,后熟45 d腐乳中的优势菌为明串珠菌（Leuconostoc）,后熟180 d腐乳中的优势菌为四联球菌（Tetragenococcus）;利用培养分离方法从腐乳发酵过程中部分样品分离鉴定出75株可培养细菌,包括融合魏斯氏菌（Weissella confuse）、蜡样芽孢杆菌（Bacillus cereus）、肉葡萄球菌（Staphylococcus carnosus）、乳酸乳球菌（Lactococcus lactis）、嗜盐四联球菌（Tetragenococcus halophilus）、粪肠球菌（Enterococcus faecalis）和耐久肠球菌（Enterococcus durans）等。     

梯形透空丁坝局部水动力特性对底栖动物生境演替的影响机制

针对因梯形透空丁坝局部水动力特性对底栖动物栖息地的影响机制尚不明确,限制了此类结构的大范围推广应用的问题,依托长江深水航道建设的示范应用工程,构建三维水动力数值模型,选择中华绒螯蟹为指示物种,研究了不同径流条件下梯形透空丁坝局部水动力特性及其对指示物种栖息地的影响;结合梯形透空丁坝不同时期沉积物和底栖动物的监测数据,分析了梯形透空丁坝对底栖动物生境演替的影响机制。结果表明：梯形透空丁坝迎流面产生的上升流将主流引导至丁坝后上方,在汛期为中华绒螯蟹提供了避洪场所;坝内及坝后较小的流速和丰富的流场结构为中华绒螯蟹提供了索饵场和越冬场。     

乌虾酱长期发酵过程中细菌群落演替及对生物胺形成的影响

针对长期发酵（1、2、3 a和8 a）的乌虾酱进行感官评价，用高通量测序技术探究细菌群落演替规律，高效液相色谱技术同步检测6 种生物胺含量。结果发现：随发酵时间延长，虾酱逐渐呈深褐色、L*值下降、b*值先上升后下降、颗粒感消失、腥味和氨味下降、鲜味在发酵2 a达到最大值。虾酱中测得的细菌分属42 个门，894 个属和600 个种；厚壁菌门和变形菌门为优势菌门，四联球菌属、嗜冷杆菌属、假单胞菌属、肠球菌属、乳酸菌属和玫瑰变色菌属为优势菌属；细菌群落多样性在发酵2 a达到峰值。虾酱中生物胺种类及含量在发酵2 a后逐渐上升，发酵8 a，样品检出腐胺、尸胺、组胺、酪胺、亚精胺和精胺。Pearson相关性分析显示，与组胺呈显著正相关的为德沃斯菌属（P＜0.05），与组胺呈极显著负相关的为芽孢杆菌属、劳尔氏菌属、发光杆菌属和葡萄球菌属（P＜0.01）；与腐胺呈极显著正相关的为劳尔氏菌属（P＜0.01），与腐胺呈显著正相关的为假单胞菌属、亚硫酸杆菌属和慢生盐场菌属（P＜0.05）；与尸胺呈极显著正相关的有不动杆菌属（P＜0.01）。本研究为虾酱中功能菌株筛选和生物胺精准防控提供一定理论依据。     

The characteristics of the bacterial community structure and population dynamics for phosphorus removal in SBR activated sludge processes

The characteristics of the bacterial community structure and population dynamics for phosphorus removal in activated sludge were investigated using laboratory-scale sequencing batch reactor (SBR) activated sludge processes fed with four different carbon sources. Phosphorus removal activity, quinone profile of the activated sludge and isolated bacterial strains were monitored. An enhanced phosphorus removal activity was accompanied by the increase in ubiquinone-9 (Q-9). The relationships between phosphorus removal activity and Q-9 contents of the isolated bacterial strains were dependent neither on the organic substrates nor on the species of isolated bacterial strains. The enhanced phosphorus removal capability of activated sludge seemed to be due to the increase in the populations of bacteria with activity of phosphorus removal, i.e. species succession of bacteria in activated sludge ecosystems, rather than the increase in the phosphorus removal capability of phosphorus removal bacteria. Not only Acinetobacter but also Pseudomonas identified from isolated strains were regarded as representative polyphosphates-accumulating organisms and predominant species to the whole of bacterial population in activated sludge for phosphorus removal.     

Chemical and biological features of a high altitude lake in the southern Alps (Laghetto Inferiore, Switzerland)

Since 1980, surveys have been performed nearly every three years on approximately 50 small high altitude alpine lakes located in the Swiss part of the Lake Maggiore watershed. On the basis of this information, since 1996 Laghetto Inferiore has been included in the Mountain Lakes Research (MOLAR) project, an extensive European cooperative research project with 23 partners. Laghetto Inferiore is located at 2074 m a.s.l.; its watershed is mainly composed of crystalline silicic rocks; it has a maximum depth of 33 m, and a theoretical renewal time of 41 days. The pH of the water is approximately 5.6; the alkalinity of the surface water is approximately 30 μmol and that of the bottom water approximately 60 μmol. Chemical studies were performed on the inputs from atmospheric deposition and the main tributary streams, the lake concentration (on a monthly basis), and the outflow. The results show that the characteristics of summer deposition (rain) differ significantly from those of winter deposition (snow). By means of a budget model it was possible to distinguish between the contribution from atmospheric deposition and the contribution from weathering. Biological studies revealed a considerable variety of phytoplankton species and a scarcity of zooplankton species. The vertical distribution of the main algal species shows a marked vertical stratification, with biomass concentrations higher in the profundal. Along this profile, the species of the same taxonomic class tend to gather in a particular depth band, while the single classes tend to be distributed at different depths, according to their specific light requirements.     

广义项目管理与施工企业项目管理

“项目管理”这一概念或者提法、做法,自80年代初期进入中国大地,至今已在社会各行业得到广泛的应用,尤其是建筑施工企业更是把“项目管理”做为自己企业管理的基础管理和核心管理,然而广义的项目管理与施工企业的项目管理在管理的性质、任务、内容、范围、主体上是有很大区别的,广大施工管理人员应对这一点有深入的了解和明确的认识。     

Integrating fire spread patterns in fire modelling at landscape scale

Fire spread modelling in landscape fire succession models needs to improve to handle uncertainty under global change processes and the resulting impact on forest systems. Linking fire spread patterns to synoptic-scale weather situations are a promising approach to simulating fire spread without fine-grained weather data. Here we present MedSpread—a model that evaluates the weights of five landscape factors in fire spread performance. We readjusted the factor weights for convective, topography-driven and wind-driven fires (n = 123) and re-assessed each fire spread group's performance against seven other control simulations. Results show that for each of the three fire spread patterns, some landscape factors exert a higher influence on fire spread simulation than others. We also found strong evidence that separating fires by fire spread pattern improves model performances. This study shows a promising link between relevant fire weather information, fire spread and fire regime simulation under global change processes.     

Influence of eco‐hydrological factors on aquatic plant succession in a regulated river: a case study of the Petchburi River,Thailand

Monitoring of aquatic plant biomass in the Petchburi River, a regulated river system in Thailand, was carried out together with the examination of eco‐hydrological characters and the sedimentary organic content. The surveys were performed during May, August and November of 2010 and 2011. The results indicated temporal variation in water velocity (0.08–2.51 m/s) and medium to low organic levels (0.58–4.68%) of the benthic substrates. Dominant aquatic plants were Hydrilla verticillata (L.F.) Royle and Potamogeton malaianus Miq. with the highest biomass of 70.84 and 182.72 g/m², respectively. The biomass was substantially decreased during the flood‐induced discharge period. This study indicates that Potamogeton has more adaptive potential to high water velocities than Hydrilla, while Hydrilla prefers lower water velocities. Discharge velocities of less than 0.5 m/s could provide positive growth rates of such submerged plants. Approaching the discharge control from this ecological point of view can further contribute to river habitat conservation.     

酱香型酒醅堆积发酵过程中优势菌群和稀有菌群对细菌总群落演替模式的影响

揭示发酵体系中稀有菌群(rare taxa,RT)和优势菌群(abundant taxa,AT)在总群落(whole taxa,WT)中的作用及影响,可为深入理解发酵过程中微生物群落结构组成机制和演替规律提供线索和依据.本研究针对细菌使用高通量测序技术,分析酱香酒第3轮次堆积发酵过程中AT、RT和条件稀有菌群(cond...     

异养菌与硝化菌在曝气生物滤池中的空间分布

研究了中试规模的上向流曝气生物滤池(Up-Flow Biological Aerated Filter,UBAF)处理生活污水时,异养菌与自养型硝化菌在反应器中的空间分布。试验阶段,进水CODCr/NH4 -N维持在6左右。水力负荷低于3m3/m2.h时,滤池中出现了两个不同的功能分区。进水端表现在有机物的快速去除,因此聚居的主要为异养菌;出水端表现为NH4 -N的迅速氧化,因此聚居的主要为硝化菌。沿滤层高度上溶解氧低谷是两个区域清晰的分界线。在进水水质稳定的情况下,影响两种微生物群落空间分布的重要因素是水力负荷,随其增加,分界线将逐渐上移,即发生了微生物群落的演替现象。当水力负荷超过3m3/m2.h时,分界线消失,硝化菌最终被竞争出反应器,此时NH4 -N的去除源于异养菌的同化作用。