凤头白鸭与连城白鸭的群体遗传多样性分析

为系统地评价、保护凤头白鸭资源的遗传多样性,进一步对其开发利用,本研究利用12个微卫星位点(STR分型技术)对凤头白鸭与连城白鸭(各60只)2个群体的遗传多样性参数进行检测和计算。结果表明:除位点AJ272578以外,凤头白鸭群体在APL2、AJ272577、AJ272579、AJ515884、APH01、AY493256、AY4932898、CMO11等8个STR位点上的等位基因多于连城白鸭,在AJ515887、AJ515893、AY493313等3个位点上与连城白鸭相等;凤头白鸭群体的有效等位基因数(Ne)、期望杂合度(He)、观察杂合度(Ho)、多态信息含量(PIC)均大于连城白鸭;2个群体的群体内近交系数(Fis)分别为-0.02、0.09,凤头白鸭群体表现为杂合子过剩。综上,凤头白鸭群体的遗传多样性较连城白鸭更为丰富。     

Effects of abrupt salinity increase on nitrification processes in a freshwater moving bed biofilter

The nitrification process is a widely used biological approach responsible for ammonia and nitrite removal in recirculating aquaculture system (RAS) biofilters. Given this pivotal role, the influence of different water quality parameter on nitrification efficiency is important information for RAS operations. One influencing parameter is salinity, and salinity fluctuations in freshwater RAS biofilters are reported to affect the nitrifying bacteria. This study investigated the effects of abrupt increase in salinity in freshwater RAS on substrate-dependent (1’-order) as well as substrate independent (0’-order) nitrification rates. A 100% inhibition was found for surface specific removal (STR) of total ammonia nitrogen (TAN) and surface specific nitrite removal (SNR) when salinity was abruptly increased to 25‰ and above. A fast turnover (i.e. steep decline in [NH₄-N⁺] and [NO₂-N⁻]) were observed at lower salinities (≤10‰), while limited/no degradation of either ammonia or nitrite was seen at salinities above 25‰. At low substrate loading (1’-order process), removal rate constants (k_1a) of 0.22 and 0.23 m d^-1 were observed for ammonia and nitrite degradation, respectively, declining to 0.01 m d^-1when adding marine RAS water increasing the salinity to 15‰. Similar observations followed at high nutrient loadings (0’-order process) with STR and SNR of 0.10 and 0.12 g N m^-2 d^-1, respectively, declining to 0.01 g N m^-2 d^-1 at 15‰. When salinities of 25‰ and 35‰ were applied, neither TAN nor nitrite degradation was seen. The results thus demonstrate a pronounced effect of salinity changes when freshwater RAS biofilters are subjected to fast/abrupt changes in salinity. RAS facility operators should be aware of such potential effects and take relevant precautions.     

STR技术在种用东北细毛羊遗传管理中的应用

以10个STR基因座作为遗传标记系统，分析东北细毛羊种群的遗传多样性和亲缘关系。在遗传多样性分析中，群体的平均等位基因数为8．2，平均杂合度为0．794，平均多态信息含量为0．768，遗传多样水平较丰富。在亲缘关系鉴定和确认中，双亲鉴定时，10个微卫星基因座的累积非父排除概率为0．9999，平均父权相对机会(RCP)为99．999％；单亲鉴定时，累积非父排除概率为0．9962，平均RCP为99．993％。根据所选的STR基因座，可建立一套适用于种用东北细毛羊遗传资源分析和亲缘关系鉴定的方法体系，为我国东北细毛羊品种资源的保护和经济性状的筛选提供科学指导。同时，也可为解决东北细毛羊归属纠纷提供一个科学的鉴定方法。     

基于STR912芯片的日光温室自动监控系统设计

采用微电子技术及计算机技术可以实现温室环境的自动控制,成为农用温室设施的发展方向。本研究以STR912为核心,设计出日光温室自动控制系统。该系统选择与其温湿度、光照及CO2浓度匹配的传感器,并对温室外设环境调节装置进行设计。控制参数可以通过所需的环境要求进行人工调节,能够满足日光大棚的多适用性。     

饱和苯酚-氯仿抽提法与Chelex-100树脂法提取DNA在研究犬STR基因座多态性中的应用比较

在研究犬STR基因座多态性中,比较使用了饱和苯酚-氯仿抽提法和Chelex-100树脂法,两种方法提取的DNA在扩增后的检测结果均能准确地反映实验结果。尽管从平均峰面积和平均峰高值等指标上,利用Chelex-100树脂法提取的DNA质量和扩增后的检测效果较饱和苯酚-氯仿抽提法差,但Chelex-100树脂提取法更为简单快捷,适合在建立警犬STR基因座等位基因数据库中和犬亲缘关系鉴定中广泛使用。     

Household dependency on forest resources in the Sariska Tiger Reserve (STR), India: Implications for management

ABSTRACT

Sariska Tiger Reserve (STR) is a virtual ecological island influenced by both anthropogenic pressures and a significant cattle population from the villages located there. The government has initiated voluntary relocation of villages, but this action has not yielded desired results as most of the residents depend on the surrounding forest for their livelihood. This study used a logit model to identify the influential factors that predict forest dependency. The results indicate that livestock population and the agricultural land per household as the two major determinants of dependency. Alternative sources of livelihood or vocational training may help in reducing villager’s forest dependency.     

Optimization of lipase-catalyzed synthesis of palm amino acid surfactant using response surface methodology (RSM)

Amino acid surfactants are high-value surfactants which have excellent emulsifying characteristics and minimal toxicity to the living body. Enzymatic synthesis of palm kernel amino acid surfactant was optimized by response surface methodology (RSM) using palm kernel olein (PKO) and l(+)-lysine catalyzed by Lipozyme RM IM. The reaction was performed in batch mode stirred tank reactor (STR) with one multi-bladed impeller. A central composite rotatable design (CCRD) was employed to evaluate the interactive effects of various parameters. The parameters were temperature (A): (40.00–70.00 °C), impeller speed (B): (100.00–400.00 rpm), substrates ratio (C): (1.00–4.00 mmol) and enzyme amount (D): (5.00–8.00 g). The optimum condition derived via RSM at fixed reaction time of 24 h was temperature; 47.50 °C, impeller speed; 323.96 rpm, substrates ratio; 3.25 mmol and enzyme amount; 7.25 g. The experimental yield was 89.03% under the optimum condition, which compared well with the maximum predicted value of 93.77%.