黄河下游凌汛变化趋势与气候变化关系分析——以济南天桥河段为例

凌汛是黄河下游严重的自然灾害之一,黄河下游天桥河段属于典型的弯曲窄河段,极易发生凌情。本文选择了天桥河段为研究对象,根据天桥河段1996-2005年凌情的实测资料,并结合济南市和郑州市气温、降水等气象要素,应用数理统计的方法,初步探讨了气候变化背景下的黄河下游凌汛的变化趋势。研究表明:在全球变暖的大背景下,济南市近10年的气候呈现冷湿趋势,而济南的上一站郑州却呈现暖湿的特点。气候的变化使得黄河下游凌汛呈现出新的特点和变化趋势,即从凌汛期持续时间、封冻历时及封河长度等综合指标来看,近10年凌情比较严重的年份大致呈现凌情轻重交替出现的特点;天桥河段与黄河下游历年凌情比较,总体上凌情变化趋向于缓和。     

硝化型和异养型生物絮团养殖系统罗非鱼养殖效果和微生物群落结构比较

为了解硝化型和异养型生物絮团养殖系统的养鱼效果,在硝化组和异养组中试养吉富罗非鱼(GIFT Oreochromis niloticus)幼鱼51 d,比较研究罗非鱼的生长性能、非特异性免疫酶活以及消化酶活性、水体及肠道微生物的群落结构。结果显示,两组罗非鱼的成活率和增重率无显著性差异;异养组罗非鱼的非特异性免疫酶活性显著高于硝化组。硝化组罗非鱼肠道的淀粉酶和脂肪酶活性均显著高于异养组,异养组的蛋白酶显著高于硝化组。罗非鱼肠道微生物占比前5的优势门均为变形菌门(Proteobacteria)、放线菌门(Actinobacteria)、绿弯菌门(Chloroflexi)、厚壁菌门(Firmicutes)和衣原体门(Chlamydiae),其中变形菌门是各组中最主要的菌群。硝化型水中占比前4的优势门为变形菌门,绿弯菌门,拟杆菌门(Bacteroidetes),浮霉菌门(Planctomycetes);异养型水中占比前4的优势门为变形菌门,绿弯菌门,拟杆菌门,放线菌门。分枝杆菌属(Mycobacterium)是水体和肠道中最主要的潜在致病菌,而Diplorickettsiaceae和邻单胞菌属...     

稻田和池塘养殖模式对中华绒螯蟹肠道菌群、免疫酶活及肌肉游离氨基酸的影响

为了探究稻田和池塘养殖模式对中华绒螯蟹(Eriocheir sinensis)肠道菌群、免疫力和肌肉风味影响,选取同一批次稻田和池塘的中华绒螯蟹在5月和10月对其肠道菌群、免疫酶活和肌肉游离氨基酸进行测定。结果表明：中华绒螯蟹肠道优势菌群为软壁菌门、拟杆菌门、变形菌门和厚壁菌门。在季节和养殖模式均对蟹的肠道菌群造成影响的情况下,季节变化对菌群变化的影响更大。从5月到10月,稻田养殖模式下中华绒螯蟹肠道菌群的丰富度和多样性均出现上升趋势,而池塘养殖模式下肠道菌群的丰富度和多样性则无显著变化。两种养殖模式下中华绒螯蟹肠道中的超氧化物歧化酶(SOD)在5月的活性均高于10月,在10月池塘模式下的免疫酶活性溶菌酶(LZM)和酸性磷酸酶(ACP)显著高于稻田模式。各组肌肉中均检测出14种呈味氨基酸,呈味氨基酸中甜味氨基酸含量(TSAA)>总苦味氨基酸(TBAA)>总鲜味氨基酸(TUAA),且池塘养殖模式下中华绒螯蟹肌肉中TSAA和总游离氨基酸TFAA高于稻田养殖模式下含量。因此,池塘养殖模式较稻田养殖模式下的中华绒螯蟹肠道菌群时间上更稳定,免疫酶活更强,肌肉风味更优。     

大青叶樱桃根际微生物种群结构及其变化动态

利用选择性培养基,对2年生大青叶樱桃(Cerasus pseudocerasus)根际微生物进行了分离、鉴定和分类,分析了不同物候期根际微生物种群结构的变化。结果表明,从大青叶樱桃根际分离纯化获得的细菌分别属于15个属,以芽孢杆菌属(Bacillus)、假单胞菌属(Pseudomonas)为主;放线菌属于链霉菌属的6个类群,以白色类群(Albosporus)、黄色类群(Flavus)为主;真菌以镰刀菌(Fusarium)和木霉属(Trichoderma)为主。不同生育期根际微生物种群结构不同,落叶期根际细菌种群结构最丰富,萌芽期最少。     

Cross talk of CCK8 and EGF in mouse neurons

AIM: To explore the mechanism of signaling transduction and cross talk between cholecystokinin octapeptide (CCK₈) and epidermal growth factor (EGF) in mouse neurons and to observe the effect of CCK₈ in coordination with EGF on neuron growth and cell viability. METHODS: For determining which kind of CCK receptor mediated the phosphorylation of EGF receptor, the cultured neurons were randomly divided into control group, CCK₈ stimulation group, CCK_A receptor antagonist group, CCK_B receptor antagonist group, and CCK_A+CCK_B receptor antagonist group. Control and stimulation groups were stimulated with DMEM and CCK₈ (10^-7 mol/L) for 5 min, respectively, while antagonist groups were pre-incubated with different types of receptor antagonists (10^-8 mol/L) for 10 min and followed by stimulating the neurons with CCK₈. For observing the effect of CCK₈ and EGF on the phosphorylation of EGFR in neurons and on neuron growth and cell viability, the cultured neurons were randomly divided into control group, CCK₈ stimulation group, EGF stimulation group and CCK₈+EGF stimulation group, which were stimulated with DMEM, CCK₈ (10^-7 mol/L), EGF (40 μg/L) and CCK₈+EGF for 5 min, respectively. Reactions were terminated by freezing the neurons in liquid nitrogen and the phosphorylated EGFR was detected by Western blotting. Meanwhile, the viability of the neurons was observed by MTT method after stimulated for 24 h, 48 h, 72 h and 96 h. RESULTS: The phosphorylation levels of EGFR were decreased in the neurons treated with either of the two CCK receptor antagonists, and more obvious decrease was observed when the two CCK receptor antagonists were used in combination. Compared with control group, the phosphorylation levels of EGFR in the neurons were significantly increased(P<0.05) after stimulated with CCK₈ or EGF, and the increase was more remarkable in CCK₈+EGF stimulation group. CCK₈ or EGF improved the viability and prolonged the life span of the neuron, and synergism of these two reagents was observed. CONCLUSION: Both CCK_A and CCK_B receptors are involved in the phosphorylation of EGFR in the neurons stimulated by CCK₈, and the type A receptor may play a more important role. There is cross-talk between CCK₈ and EGF signaling pathways in neurons. The signaling cross-talk between CCK₈ and EGF may be the underlying molecular mechanism responsible for the synergistic effect on the neuron growth and viability in vitro.     

银杏光合特性的研究

银杏的光饱和点为１０６２．２μｍｏｌ．ｍ＾－２．ｓ＾－１,光补偿点为３３．８μｍｏｌ．ｍ＾－２,ｓ＾－１。银杏光合作用受叶片内部气孔调节和外部空气相对湿度,光量子通量密度等因子影响,净光合速率的日变化在强光,高温,干燥的晴天呈双峰曲线型,在多云天气呈单峰曲线型。净光合速率的年变化呈双峰曲线型,主峰出现在６月上旬,次峰在９有旬,５月下旬和７月中旬叶片光合能力最强。     

食用菌双翅目害虫的采集和玻片标本制作方法

主要提供了食用菌双翅目标本的采集方法和玻片标本的制作方法。标本的采集主要是在菇房用吸虫管采集,或者用毛笔蘸取酒精直接采集;玻片的制作分为5个步骤,即浸解脱色、洗涤、脱水、整姿封盖和干燥。     

我国食用菌眼蕈蚊的研究现状

简要综述了我国食用菌害虫眼蕈蚊的研究概况,统计了危害食用菌的眼蕈蚊科5属20余种,概述了眼蕈蚊的危害特点、生物学特性及防治方法等。并探讨了研究中存在的问题和今后的发展方向。     

火龙果果实与种子产量性状的相关性研究

以红肉火龙果（Hylocereus polyrhizus）的果实为材料,对火龙果的果实和种子的产量性状进行考察,研究果实产量性状与种子产量性状的相关关系,探索火龙果的产量形成机制。对火龙果果实按照大小分组取样,对火龙果的种子产量性状和果实产量性状进行统计及相关性分析。结果表明：单个火龙果的种子数量、种子质量与火龙果的果实质量高度相关;火龙果果实的横径、纵径与果实质量高度相关;火龙果的种子百粒重(质量)与果实质量、果实横径、果实纵径的相关不显著。因此,在火龙果栽培中,采取合适的栽培管理措施,增加果实中的种子数量,有利于提高火龙果的果实产量。     

城市慢行空间美景度评价 ——以贵阳市小车河沿河河谷慢行空间为例

以贵阳市小车河沿河河谷慢行空间为研究对象,通过实地调查选取能够较好地反映慢行空间景观特征与景观效果的20处景观样点作为评价对象,运用基于心理物理模式的美景度评价法计算景观样点的美景度值,再通过景观要素分解量化得到景观要素评值,运用回归分析建立慢行空间美景度评价模型,进而对慢行空间美景度进行评价.结果表明,形态优美、具有...