营养盐浓度对航天搭载盐藻生长及胞外多糖含量的影响

比较了培养液中不同营养盐浓度对“神舟5号”搭载盐藻(Dunaliella salina)和非搭载盐藻的生长及胞外多糖积累的影响,发现经“神舟5号”搭载后盐藻最适营养盐浓度发生了变化。非搭载盐藻培养液中最佳单因子组合为:CaC l2200 mg/L、MgC l2500 mg/L、KNO31 000 mg/L、KH2PO455 mg/L。搭载盐藻培养液中最佳单因子组合为:CaC l2250 mg/L、MgC l2500 mg/L、KNO31 000 mg/L、KH2PO415 mg/L。搭载和非搭载盐藻胞外多糖累积的最佳单因子组合相同:CaC l2、MgC l2、KNO3、KH2PO4分别为250、2 000、500、15 mg/L,但搭载盐藻胞外多糖的分泌明显高于非搭载盐藻。     

磷浓度对小环藻、大型溞和金鱼藻三者相互作用的影响

为了解磷浓度对水生植被恢复和生物操纵效果的影响, 分别用小环藻(Cyclotella sp.)、大型溞(Daphnia magna)和金鱼藻(Ceratophyllum demersum)代表浮游植物、浮游动物和大型沉水植物建立水生微宇宙模型, 在25℃、2600 lx光强和11 mg/L氮浓度条件下, 分别研究小环藻与大型溞、小环藻与金鱼藻、小环藻-大型溞-金鱼藻共培养时4种磷浓度(0.05、0.1、0.5和2 mg/L)下小环藻、大型溞、金鱼藻的增长率以及培养液中氮磷去除率的变化。结果表明: 小环藻与大型溞、小环藻与金鱼藻两两共培养时, 磷浓度为0.05-2 mg/L时, 金鱼藻和大型溞均生长良好, 小环藻受到明显抑制, 其密度保持较小幅度的正增长。在小环藻-大型溞-金鱼藻三者共培养时, 在0.05-2 mg/L的磷浓度范围内大型溞和金鱼藻生长良好, 与两两共培养相比, 小环藻则受到了更大程度的抑制, 在磷浓度为0.05-0.1 mg/L时藻密度呈现负增长. 这说明在水生态系统中, 大型浮游动物和沉水植物对浮游藻类的联合控制效果远好于各自单独的控制效果, 该控制效果随磷浓度的提高而减弱, 以0.1 mg/L的磷浓度为最佳。在实验结束后测定氮磷去除率发现, 在最低磷浓度(0.05 mg/L),即磷限制时, 水中磷去除率最高, 在最高磷浓度(2 mg/L), 即氮限制时, 水中氮去除率最高。     

氮浓度对铜绿微囊藻、大型溞和金鱼藻三者相互作用的影响

为了解氮浓度对生物操纵和草-藻竞争的影响, 选取铜绿微囊藻、大型溞和金鱼藻分别作为浮游植物、浮游动物和沉水植物的代表, 在温度25℃, 光强2600 lx, 光暗比14h﹕10h, 磷浓度1.5 mg/L时, 研究5种氮浓度(0.5、2、4、8和16 mg/L, 用KNO₃溶液配制)下, 溞-藻, 草-藻和溞-草-藻共培养时各自的增长率和培养液中氮磷削减率的变化。结果表明: 在单独培养铜绿微囊藻时, 氮浓度控制在1.97 mg/L以下, 可有效降低培养液中藻的增长率。在溞-藻共培养时, 大型溞有效控藻的氮浓度范围为0.5—4 mg/L; 在草-藻共培养时, 有效控藻的氮浓度范围为0.5—2 mg/L, 对应氮浓度下(0.5和2 mg/L), 实验末期铜绿微囊藻细胞密度分别是溞-藻共培养的23.89%和21.51%, 控藻效果更好; 在溞-草-藻三者共培养时, 有效控藻的氮浓度范围为0.5—16 mg/L, 且氮浓度为0.5—4 mg/L时, 大型溞和金鱼藻的增长率均显著大于铜绿微囊藻, 铜绿微囊藻的增长率均为负值, 控藻效果最好。大型沉水植物的加入, 可以有效提高生物操纵的控藻效果, 减少水中氮磷含量, 长期有效地改善水质。     

4株微藻悬浮和固定培养生长和氮磷去除效果的比较

为了比较牟氏角毛藻(Chaetoceros muelleri)、蛋白核小球藻(Chlorella pyrenoidosa)、三角褐指藻(Phaeodactylum tricornutum)、新月柱鞘藻(Nitzschia closterium)四株微藻在悬浮和固定培养方式下藻细胞生长状况和氮磷去除效果,试验采取模拟含氮磷人工污水,向培养液中添加NH₄Cl,在相同培养条件下,分别培养4株微藻。实验结果表明:4株微藻在悬浮和固定化培养均能生长,氮磷去除效果良好。4种微藻悬浮培养的生长速率要优于固定化培养。两种培养方式生长速率均为:蛋白核小球藻>新月柱鞘藻>三角褐指藻>牟氏角毛藻;4种藻在悬浮培养下,NH₄⁺-N和PO₄^3--P去除率为:新月柱鞘藻>三角褐指藻>牟氏角毛藻>蛋白核小球藻;4种藻在固定化培养下,NH₄⁺-N和PO₄^3--P去除率为:新月柱鞘藻>...     

氮磷浓度对藻-溞-草间相互作用的影响

为了解氮磷浓度对生物操纵效果的影响, 以小球藻、大型 溞和金鱼藻分别作为浮游植物、浮游动物和大型沉水植物的代表, 建立了它们之间相互作用的水生微宇宙模型。研究了在 25℃、2000—3000 lx 的温度和光照下, 不同氮磷浓度对三者生长的影响。结果表明: 两者共培养时, 在高氮(10.5 mg/L)条件下, 磷浓度小于 0.1 mg/L 对大型 溞繁殖和金鱼藻的生长有利; 磷浓度介于 0.1—2 mg/L 时小球藻呈大暴发趋势, 而金鱼藻的生长则明显受抑制。在低氮(0.5 mg/L)条件下, 磷浓度不大于 0.5 mg/L, 大型 溞对小球藻有较好的抑制作用, 金鱼藻与小球藻无显著互抑现象; 磷浓度增大为 2 mg/L 时, 小球藻对金鱼藻生长产生明显抑制。在 0.05—2 mg/L 的磷浓度范围及高氮和低氮条件下三者共培养时, 大型 溞数量及金鱼藻生物量均不同程度的升高,且小球藻数量得到了有效抑制, 以磷浓度为 0.1—0.5 mg/L 时效果最佳; N/P 比值对藻、溞 、草间的相互作用有重要影响, 在藻-溞系统中, 大型沉水植物的加入可以大大提高控藻效果, 减小 N/P 比值波动带来的不利影响。与低氮情况相比, 高氮条件对金鱼藻、大型 溞及小球藻的增长均存在一定抑制作用。磷浓度为 0.5 mg/L时的水体氮磷去除效果好于其他磷浓度梯度。     

磷浓度对铜绿微囊藻、大型溞和金鱼藻三者相互作用的影响

为了解磷浓度对生物操纵和水生植被恢复效果的影响,以铜绿微囊藻、大型溞和金鱼藻分别作为浮游植物、浮游动物和大型沉水植物的代表,在25℃、2000—3000lx光强和11mg/L氮浓度条件下,研究两者和三者共培养时4种磷浓度(0.2、0.5、1.0、1.5 mg/L)下各自的增长率和培养液中氮磷去除率的变化。结果表明:两者共培养时,磷浓度不大于0.2mg/L时,有利于大型溞的繁殖和金鱼藻的生长;磷浓度介于0.5—1.5mg/L时,铜绿微囊藻呈正增长趋势,而金鱼藻的生长则明显受抑制。三者共培养时,所有磷浓度下的大型溞数量及金鱼藻生物量均不同程度的升高,且铜绿微囊藻的生长得到了有效抑制,以磷浓度为0.2—0.5mg/L时效果最佳;N/P比值对藻、溞、草间的相互作用有重要影响,在藻-溞系统中,大型沉水植物的加入可以大大提高抑藻效果,减小N/P比值波动带来的不利影响。磷浓度为0.5mg/L时的水体氮磷去除效果好于其他磷浓度梯度。     

温度、盐度和食物条件对西藏拟溞摄食强度的影响

报道了不同温度、盐度和饵料条件下西藏拟溞的摄食强度、西藏拟溞对不同饵料生物蛋白核小球藻(Chlorellapyrenoidesa)、牟氏角毛藻(Chaetoceros muelleri)、湛江等鞭金藻(Isochrysis zhanjiangensis)、亚心形扁藻(Platymonas subcordiformis)、盐藻(Dunaliella salina)、新月拟菱形藻(Nitzschiella closterium)的选择性以及摄食节律。结果表明,在适温范围(2 20℃)内,西藏拟溞的滤水率、摄食率随着温度的升高而增加,14 16℃为西藏拟溞的适宜温度。在盐度20时,西藏拟溞的摄食率最高,幼、成溞对等鞭金藻的摄食率分别为1.88 ng C/(ind.h)和3.46 ng C/(ind.h)。西藏拟溞对角毛藻的滤水率和摄食率均随着龄期增加而增加,而对等鞭金藻呈相反趋势,但二者的日粮均随体长增大而减小。幼、成溞的滤水率和摄食率随食物密度变化的趋势基本一致,均是在盐藻密度为1×106 ind./L时均最高,分别为0.194、0.221 mL/(ind.h)和0.030μgC/(ind.h)和0.034μgC/(ind.h)。幼溞对6种藻的食物选择性为角毛藻小球藻盐藻扁藻金藻拟菱形藻;成溞为扁藻角毛藻盐藻金藻小球藻拟菱形藻。幼溞、成溞均对角毛藻和盐藻的选择性较好。西藏拟溞的幼溞和成溞对牟氏角毛藻的摄食有相同的节律,在15:00 17:00和01:00 03:00时有两个摄食高峰,在09:00 11:00和23:00 01:00有两个低谷。     

镇海水库拟柱孢藻的分离鉴定和氮磷对其生长的影响

以分离自广东省镇海水库的拟柱孢藻N8为对象,探究其在不同磷浓度及氮磷浓度组合下的生长情况。结果表明,拟柱孢藻N8对磷的适应范围很宽,在0.02—5.12 mg/L磷浓度下均能生长,最适生长磷浓度范围为0.16—5.12 mg/L,磷浓度的升高能显著延长拟柱孢藻的对数生长期和提高生物量。动力学分析表明,拟柱孢藻N8有较低的KSP值,对磷元素的亲和性较高,在磷营养贫乏的环境下更容易形成优势。在氮磷组合实验中,低氮(0.5 mg/L)显著抑制拟柱孢藻的生长,且这种生长抑制不受磷浓度的影响;而在低磷(0.04 mg/L)条件下,水体中氮浓度的增加会显著促进拟柱孢藻的生长,拟柱孢藻在高氮中磷和高氮高磷下的生长显著优于其他氮磷组合条件。研究表明,广东省水库拟柱孢藻的生长受磷的限制较弱,氮是其生长的决定因子。     

富营养废水中碳氮磷浓度对布朗葡萄藻总脂和总烃的影响

以经过二次过滤的富营养化鱼塘养殖污水为培养液,添加外源的碳、氮、磷元索,研究了污水中不同的外源无机碳、总氮和总磷浓度对布朗葡萄藻(Botryococcus braunii)生物量、总脂和总烃含量的影响.结果表明:(1)以NaHCO3作为碳源,布朗葡萄藻的生物量和总脂含量在外源无机碳浓度为5～10 mg/L时最高,总烃含量在外源无机碳浓度为15mg/L时最高.(2)以KNO3作为氮源,布朗葡萄藻的生物量在总氮浓度为15mg/L时最高,总脂含量在总氮浓度为2mg/L时最高,总烃含量在总氮浓度为20mg/L时最高.(3)以KH2 PO4作为磷源,布朗葡萄藻生物量在总磷浓度为2mg/L时最高,总脂含量和总烃含量在总磷浓度为1.5 mng/L时最高.     

温度和氮磷浓度对平裂藻和栅藻生长及竞争的影响

为了解温度及氮磷浓度对平裂藻和栅藻生长及竞争的影响,分别在18、25和35℃条件下,以BG11培养基为基础,设置了不同的氮磷浓度组,进行了2种藻的单独培养试验和混合培养试验,结果表明:在纯培养条件下,低营养浓度组(磷浓度分别为0.1和0.5 mg/L)平裂藻在3种温度下基本停止生长,高营养盐浓度组(磷浓度分别为1.0和1.5 mg/L)除18℃1.0 mg/L组停止生长外,其余均能正常生长增殖,且细胞最大密度表现为25℃18℃35℃,1.5和1.0 mg/L浓度组细胞生长差异不显著。栅藻在纯培养条件下,细胞密度总体表现为随着营养盐浓度升高而增加的趋势,细胞最大密度表现为18℃25℃35℃。在混合培养试验中,除35℃、1.5 mg/L组平裂藻对栅藻的竞争抑制参数大于栅藻对平裂藻的竞争抑制参数外,其余试验组均表现为栅藻受平裂藻影响较小。在混合培养体系中,0.1 mg/L组平裂藻仍基本停止生长,0.5 mg/L组受栅藻的刺激作用,生长优于纯培养体系。1.0和1.5 mg/L组均受栅藻的抑制作用,且浓度越高抑制作用越强。     

壳聚糖酶的克隆表达与壳寡糖的制备分析

目的:克隆壳聚糖酶基因于大肠杆菌中实现高表达,制备壳寡糖。方法:以枯草芽孢杆菌总DNA为模板扩增壳聚糖酶基因(CSN),克隆至载体pET23a(+)上,转化菌株BL21(DE3)。重组子经0.5 mmol/L IPTG诱导后,SDS-PAGE和质谱检测与鉴定重组酶。酶纯化后水解壳聚糖,薄层色谱分析其水解产物。结果:质谱证明壳聚糖酶(31.5kDa)成功表达,表达量占菌体总蛋白的45%左右。纯化后重组酶浓度为900 mg/L,纯度95%、回收率85%,酶活力为10 000 U/mg。壳聚糖降解产物为壳二糖至壳四糖。结论:原核表达载体pET23a(+)-CSN构建正确,壳聚糖酶表达量与活性高,适用于水解壳聚糖制备壳寡糖。     

国内外蝗害治理技术现状与展望

本文首先概述了国内外蝗虫发生与为害的态势,总结了现阶段我国蝗虫发生与为害的主要特点:即农田飞蝗暴发频繁而且严重,草原土蝗的发生时常造成严重的经济损失,而且侵入城市干扰市民生活,我国与周边国家之间蝗虫过境迁移频繁,使用化学农药污染环境和农产品;分析了国内外蝗虫防治对策与技术的发展现状,重点介绍了应急防治和可持续治理对策、...     

Molecular characterisation of species and genotypes of Cryptosporidium and Giardia and assessment of zoonotic transmission

The molecular characterisation of species and genotypes of Cryptosporidium and Giardia is essential for accurately identifying organisms and assessing zoonotic transmission. Results of recent molecular epidemiological studies strongly suggest that zoonotic transmission plays an important role in cryptosporidiosis epidemiology. In such cases the most prevalent zoonotic species is Cryptosporidium parvum. Genotyping and subtyping data suggest that zoonotic transmission is not as prevalent in the epidemiology of giardiasis. Molecular characterisation of Cryptosporidium and Giardia is a relatively recent application that is evolving as new genes are found that increase the accuracy of identification while discovering a greater diversity of species and yet unnamed taxa within these two important genera. As molecular data accumulate, our understanding of the role of zoonotic transmission in epidemiology and clinical manifestations is becoming clearer.     

白术同源四倍体的诱导和鉴定及其与二倍体过氧化物酶的比较

以白术（Atractylodes macrooephala Koidz.）二倍体组培苗为材料,对其四倍体诱导方法进行研究,共获得45个白术同源四倍体株系,为优良株系的选育提供了材料。此外,还分析比较了其中8个白术四倍体株系与二倍体的过氧化物酶同工酶（POD）的酶谱差异,发现四倍体各株系过氧化物酶同工酶谱比二倍体的均多了Rf0.310的谱带,且总过氧化物酶比活力也发生了很大改变,对探讨白术四倍体优良株系的生理生化机理具有一定的参考价值。     

Synthesis and turnover of cerebrosides and phosphatidylserine of myelin and microsomal fractions of adult and developing rat brain.

The synthesis and turnover of cerebrosides and phospholipids was followed in microsomal and myelin fractions of developing and adult rat brains after an intracerebral injection of [U-14C]serine. The kinetics of incorporation of radioactivity into microsomal and myelin cerebrosides indicate the possibility of a precursor-product relationship between cerebrosides of these membranes. The specific radioactivity of myelin cerebrosides was corrected for the deposition of newly formed cerebrosides in myelin. Multiphasic curves were obtained for the decline in specific radioactivity of myelin and microsomal cerebrosides, suggesting different cerebroside pools in these membranes. The half-life of the fast turning-over pool of cerebrosides of myelin was 7 and 22 days for the developing and adult rat brain respectively. The half-life of the slowly turning-over pool of myelin cerebrosides was about 145 days for both groups of animals. The half-life of the rapidly turning-over microsomal cerebrosides was calculated to be 20 and 40 h for the developing and adult animals respectively. The half-life of the intermediate and slowly turning-over microsomal cerebrosides was 11 and 60 days respectively, for both groups of animals. The amount of incorporation of radioactivity into microsomal cerebrosides from L-serine was greatly decreased in the adult animals, and greater amounts of the precursor were directed towards the synthesis of phosphatidylserine. In the developing animals, considerable amounts of cerebrosides were synthesized from L-serine, besides phosphatidylserine. The time-course of incorporation indicated that a precursor-product relationship exists between microsomal and myelin phosphatidylserine. The half-life of microsomal phosphatidylserine was calculated to be about 8 h for the fast turning-over pool in both groups of animals.     

Identification and composition of the tonsillar and anal enterococcal and streptococcal flora of dogs and cats

Enterococcus faecalis was the most frequently isolated enterococcal species from anal swabs and tonsils of dogs and cats, although in the anal samples from dogs Ent. hirae was found almost as often as Ent. faecalis. Most Ent.faecium strains from dog tonsils differed from those associated with humans and other animals in that they fermented sorbitol. Typical Ent. avium as well as atypical Ent. avium -like strains were seen in dogs, while the related species Ent. raffinosus was associated with cat tonsils. Enterococcus cecorum also occurred mainly in cats. Certain atypical strains, presumptively identified as Ent. cecorum , shared characteristics with Ent. columbae.
The most frequent streptococcal species in tonsils of cats and dogs were Streptococcus suis and Strep. canis. Streptococcus canis and Strep. bovis predominated in anal swabs. The canine Strep. suis differed from the common porcine strains in fermenting mannitol.
Forty-seven of the 288 isolates examined could not be identified or related to known species. The characteristics of two groups of these bacteria, provisionally called 'Ton 31 group' and 'O7 group' are described.     

Comparison of BMI and percentage of body fat of Indian and German children and adolescents

Today, serious health problems as overweight and obesity are not just constricted to the developed world, but also increase in the developing countries (Prentice 2006, Ramachandram et al. 2002). Focusing on this issue, BMI and percentage of body fat were compared in 2094 schoolchildren from two cross-sectional studies from India and Germany investigated in 2008 and 2009. The German children are in all age groups significantly taller, whereas the Indian children show higher values in BMI (e.g. 12 years: Indian: around 22 kg/m2; German: around 19 kg/m2) and in the percentage of body fat (e.g. 12 years: Indian: around 27%; German: around 18-20%) in most of the investigated age groups. The Indian children have significantly higher BMI between 10 and 13 (boys) respectively 14 years (girls). Indian children showed significant higher percentage of body fat between 10 and 15 years (boys) and between 8 and 16 years (girls). The difference in overweight between Indian and German children was strongest at 11 (boys) and 12 (girls) years: 70% of the Indian but 20% of the German children were classified as overweight. In countries such as India that undergo nutritional transition, a rapid increase in obesity and overweight is observed. In contrast to the industrialized countries, the risk of overweight in developing countries is associated with high socioeconomic status. Other reasons of the rapid increase of overweight in the developing countries caused by different environmental or genetic factors are discussed.     

Carnitine and creatine content of tissues of normal and alloxan-diabetic sheep and rats

The concentration of carnitine in liver increased 28-fold and urinary carnitine excretion 5-fold in alloxan-diabetic sheep. In contrast there were no similar increases in alloxan-diabetic rats. The creatine content of liver decreased 3-fold and creatine excretion decreased 2-fold in diabetic sheep. In contrast the creatine content of liver increased nearly 4-fold in diabetic rats with no change in creatine excretion. The marked increased in production of carnitine by the liver of the diabetic sheep appears possible because of decreased production and excretion of creatine.