Microcalorimetric Investigation of Influence of Fungicide SYP-L190 on Growth Metabolism of Tetrahyrnena therrnophila and Bacillus thuringiensis

Flumorph (SYP‐L190) is a new systemic fungicide with good protective, curative and antisporulant activities but no phytotoxicity to certain plants. Its performance on the environmental ecosystem is unknown. Tetrahymena thermophila and Bacillus thuringiensis are two of biological indicators for the aquatic and soil environmental ecosystem respectively. Microcalorimetric technique based on the heat output was applied to evaluate the influence of fungicide flumorph (SYP‐L190) on the two microorganisms. The thermogenic curves and corresponding thermodynamic and thermokinetic parameters were obtained. SYP‐L190 at a concentration of 50–100 µg·mL^?1 had 5% –10% inhibitory ratios aganist Tetrahymena thermophila and was used as a protection reagent, while at a concentration of 100–200 µg·mL^?1 SYP‐L190 had 10% –20% inhibitory ratios and was used as a therapy reagent. The metabolic thermogenic curves of Bacillus thuringiensis contained bacterial growth phase and sporulation phase. The SYP‐L190 at a concentration of 0–200 µg·mL^?1 had no influence on bacterial growth phase, but led to a little lag of the sporulation phase with a constant heat output. Hormesis was obviously observed in present study.     

青岛近岸水体夏冬季浮游病毒、细菌分布特征及其与环境因子的关系

应用平板涂布培养计数法及荧光显微镜计数法,研究了青岛近岸海域可培养异养细菌数量,浮游病毒、细菌丰度及生物量的分布特征,探讨了它们与温度、溶解氧、叶绿素a、硝酸盐和磷酸盐之间的关系.结果表明:夏、冬两季青岛沿岸可培养异养细菌数量介于1.01×104～183.54×104cfu/L之间,其分布随温度、叶绿素a变化不明显,而与海水硝酸盐含量显著正相关,硝酸盐是可培养异养细菌数量的主要限制因子.调查海区浮游细菌丰度介于1.00×109～8.48×109cells/L,细菌生物量介于14.19～131.95 μg/L,浮游细菌丰度与温度呈显著正相关关系,温度是造成浮游细菌季节分布差异的重要因素之一;冬夏季浮游病毒丰度介于2.39×1010～22.02×1010VLPs/L之间,浮游病毒丰度变化主要与海水溶解氧、磷酸盐含量及浮游细菌丰度有关,夏、冬两季表层浮游病毒丰度总体呈现近岸高于远岸的趋势,而底层则表现出远岸高于近岸的趋势.     

新疆吐鲁番盆地的嗜热细菌

从新疆吐鲁番盆地分离出十二株嗜热(生长温度为:25℃～73℃,最适温度为:45℃～60℃)、革兰氏阳性芽孢杆菌,经鉴定为Bacillus spp。     

Stochastic Resonance in a Bacterium Growth System Subjected to Colored Noises

We present the logistic growth model to study the stochastic resonance （SR） in a bacterium growth system under the simultaneous action of two external multiplicative cross-correlation noises and periodic external forcing. The expression of the signal-to-noise ratio （SNR） for a bacterium growth system is derived by using the theory of SNR in the adiabatic limit. Based on SNR, we discuss the effects of self-correlation time τ1 and τ2, cross-correlation time 3-3 and cross-correlation strength λ on the SNR. It is found that the self-correlation time τ1 and τ2, and cross-correlation strength λ enhance the SR of the bacterium growth system, while cross-correlation time τ3 weakens the SR of the bacterium growth system.     

紫外、氦氖激光等复合诱变产果胶酶细菌ZH1的研究

ZH₁菌株是从自然界分离筛选而来的,该菌株产果胶酶的最适pH为7.0;最适温度33℃;培养36h达产酶高峰,酶活力为73.5μ/mL,将ZH₁作为出发菌株,经紫外线诱变、硫酸二乙酯诱变,亚硝基胍和紫外线复合诱变及氦氖激光等多次反复诱变,选育得到一株产果胶酶性稳定且酶活明显提高的突变株ZHg,其酶活为301m/mL,比出发菌株ZH₁产果胶酶能力提高3.1倍.     

Nonclasssical Properties in Two-Mode Fields Resonantly Interacting with a Three-Level -Type Atom

Some noclassical properties in electromagnetic field are investigated for the interaction of two-modes initially taken in coherent-state representation with the three-level -type atom, such as squeezing properties and violation of the Cauchy-Schwartz inequality. The enhancement of field squeezing is found by selective atomic measurement. The Cauchy-Schwartz inequality is violated by the application of the classical field followed by detection in excited state.     

德耳布吕克（Delbrück，Max，1906-1981）德国-美国微生物学家（Microbiologist，Germany-America）

德耳布吕克1930年在格廷根大学获博士学位，在哥本哈根玻尔手下做博士后研究工作，后到柏林和哈恩及迈特纳一起工作。希特勒上台后，他离开德国，于1937年到达美国。当他还在柏林时，兴趣就开始从核物理转到了遗传学。在加利福尼亚理工学院，他又开始为噬菌体所吸引。噬菌体是以细菌细胞为食的较大的病毒。他发现，一个细菌细胞一旦被一个噬菌体所感染，这个细胞经过半个小时就会分裂，并产生100个噬菌体，每个噬菌体又随时会感染另一个细菌细胞。     

纳米水泡的粘附性与滑移性

为什么有些材料的表面出奇地光滑 ,或者说具有反常的粘附性 ,现在可以用存在着 2 0— 30ｎｍ大小的水泡来解释 ,这种水泡称为纳米水泡 .一块疏水性的材料浸没在水中时 ,其表面会形成一层小水泡 .当两块疏水性表面相互接近时 ,粘附在材料表面的纳米水泡就会联结这两块材料 ,而纳米尺度就是它们相互吸引力的力程长度 .另一方面 ,在某些特定材料的表面形成的纳米水泡能使水在该表面非常容易流动 ,即纳米水泡起了一种润滑剂的作用 ,例如现在流行的一种由疏水性材料制成的奥林匹克游泳衣 .对纳米水泡性质的测定具有一定的偶然性 ,因为对它们的检…     

生物计算机前景迷人

 生物分子电子技术是利用生物分子信息功能来装配电子元件和仪器的技术。目前,科学家已经了解和掌握了多种生物系统进行信息处理与传输信息的机理和模式:结构开关模式(利用电子从共价键传入和传出,改变分子状态);光学开关模式(利用特殊波长的光照射某些蛋白质,使蛋白质改变状态,选择和控制两种稳定结构表示开与关两种状态);“锁---匙”模式(利用酶的2种作用模式);非电子扰动模式(利用一个分子与蛋白质作用,使蛋白质振动而形成开关);此外还有以膜为基础的传感和控制模式、排列分子组合模式和生物分子非线性化学动力学模式等。     

与Pi—2（t）基因连锁的栽培稻BAC克隆在药用野生稻和栽培稻中的比较物理定位

用栽培稻遗传图第6连锁群中与Pi-2(t)紧密连锁的RFLP标记RG64及其筛选出来的BAC克隆38D17作为探针,对药用野生稻和栽培稻进行荧光原位杂交(FISH),供试探针RG64及BAC克隆38D17均被定位于药用野生稻和栽培稻第6染色体.药用野生稻杂交信号的百分距离分别为44.87士5.33和46.50士4.57,而栽培稻则为35.85士3.06和36.05±2.44,信号检出率相应地为7.14%、42.53%、8.09%和40.78%.BAC克隆和RFLP探针杂交位置几乎一致,由此推知,与抗性基因Pi-2(t)连锁的BAC克隆在药用野生稻中的同源顺序就在第6染色体杂交信号出现的相应位置.在未封阻的情况下,药用野生稻多个染色体上具有信号,这表明它和栽培稻的Cot-IDNA重复序列在一定的程度上具有同源性.文中讨论了栽培稻BAC克隆对药用野生稻原位杂交物理作图的可行性和Cot-IDNA的制备所涉及的一些技术问题.