甘油转化生产1,3-丙二醇发酵液中甘油含量的测定

对文献介绍滴定法测定甘油的方法进行了改进,使之能够用于1,3－丙二醇发酵液中甘油含量测定。实验表明,化学滴定法测定结果具有较好的准确性和重复性,与酶法和变色酸比色法相比,测定结果接近,化学滴定法测定发酵液中甘油含量是一个较为经济简便的方法。     

影响克拉维酸生物合成的氨基酸

发酵液的氨基酸分析显示,谷氨酸,精氨酸,天门冬氨酸,丙氨酸易被棒状链霉菌利用,发酵培养基中添加上述氨基酸后,谷氨酸,精氨酸有利于克拉维酸的生物合成,适时添加谷氨酸,精氨酸可分别提高克拉维酸的产量约25%和12%;而蛋氨酸,半胱氨酸含S氨基酸对克拉维酸生物合成不利,不同来源的黄豆粉作发酵培养基氮源,因其组成中某些氨基酸含量的差异。可使克拉维酸的产量相差百分之十几。     

发酵液中柠檬酸含量的分光光度法测定

目前,柠檬酸一般采用微生物发酵方法生产。以糖质为原料的柠檬酸发酵液中,除柠檬酸外,尚可能含有草酸、乌头酸、苹果酸和葡萄糖酸等。由于生产菌种和工艺技术的不同,各种酸的含量也不完全一样,用碱滴定测总酸的方法不能反映柠檬酸的真实含量。因此,多以五溴丙酮法进行测定。但是,以糖蜜作原料的柠檬酸发酵中,由于原料所含杂质的干扰,给测定造成很大困难。为寻找一个适于以糖蜜为原料的发酵液中柠檬酸含量的测定方法,我们采用紫外分光光度计法进行测定,结果表明:该法最大相对误差不超过3.7％。     

甘油对粒毛盘菌DP5胞外多酚积累的影响

【目的】探明以甘油为碳源促进粒毛盘菌DP5积累多酚的可能原因。【方法】对碳源种类、甘油浓度、曲酸、抑制剂和前体等对多酚产量和生物量的影响进行分析。【结果】以甘油为碳源,能显著提高粒毛盘菌胞外多酚产量。甘油浓度为20 g/L时,胞外多酚产量最高,达到0.664 g GAE/L,并在发酵液中检测到曲酸,其含量为0.25 g/L。向以蔗糖为碳源的发酵液添加曲酸,胞外多酚含量从0.209 g GAE/L提高至0.376 g GAE/L。以甘油为碳源的发酵液中,酚氧化酶活性较低。粒毛盘菌DP5通过莽草酸途径和聚酮途径合成多酚,甘油有利于莽草酸途径和聚酮途径前体物质的合成。【结论】粒毛盘菌以甘油为碳源合成出曲酸,曲酸抑制多酚向黑色素的转化;甘油促进多酚前体的合成,从而提高了粒毛盘菌胞外多酚的积累量。     

克拉维酸产生菌的优化培养

为提高克拉维酸产量,通过摇瓶实验考查了多种氮,碳源及无机盐对克拉维酸产量的影响,并对产生菌的部分性能进行了考查,试验表明实验中所用棒状链霉菌（Strepto-myces elavuligerus）合成克拉维酸的最佳氮,碳源及无机盐是黄豆粉,甘油,KH2PO4,MgSO4,其最佳培养基配比（%）分别为2.8、1.8、0.04、0.05。为保证克拉维酸高产,稳产,产生菌斜面冷藏时间不宜超过1个月,斜面传代次数不宜超过4代,沙土,20%甘油溶液,冷冻干燥管均可用于产生菌的孢子保藏。     

基因工程菌高密度发酵液中碳源物质甘油的定量检测及其浓度的优化控制

比较了高碘酸氧化法,铜离子络合法、高压液相色谱法和甘油激酶法四种不同的方法定量测定重组工程菌ＹＫ５３７／ＰＳＢ－ＴＫ高密度发酵液中甘油的浓度,发现甘油激酶法可以排除发酵液中其他物质的干扰,精确测定甘油的含量。在此基础上对发酵培养中甘油的浓度进行了优化,结果表明,甘油浓度控制在较低的水平有利于菌体密度的提高。在５Ｌ自动发酵罐中,控制甘油浓度在５ｇ／Ｌ左右,经２０ｈ的培养,最终细菌密度达到１２０ＯＤ６     

利用高效液相色谱法测定单细胞蛋白发酵液中氨基酸

利用酵母菌发酵工业废糟渣生产单细胞蛋白 (SCP)类饲料 ,其发酵液也含有蛋白类物质 ,酸水解后用高效液相色谱法测定氨基酸含量 ,结果表明 :酵母菌发酵液中氨基酸含量全面 ,总量达 2 95 .1mg·L- 1 ,有较高的应用价值。     

气相色谱法测定发酵液中胆固醇的含量

气相色谱法测定了发酵液中胆固醇的含量。采用Rtx-1（100%二甲基聚硅氧烷）毛细管色谱柱、FID检测器进行分析测定。当胆固醇浓度在0～200μg/mL范围内与色谱峰面积呈良好线性关系（r=0.9981）。方法的平均回收率为99.38%,相对标准偏差为0.75%（n=8）,最低检出限可达到0.816μg/mL。气相色谱法作为发酵液中胆固醇含量的快速测定方法,具有试剂用量少、操作简单、结果准确等特点。     

高效液相色谱法测定细菌发酵液中的糖、甘油和乙醇的研究

目的：建立一种用高效液相色谱快速测定细菌发酵液中糖、甘油和乙醇的方法。方法：酌情取细菌发酵液样品适量(1—9mL)于10mL容量瓶中,加入10mg/mL的甘露醇内标物1．0mL,用水定容到刻度,取2mL用4．5μm滤膜过滤,进样2μL分析,糖、甘油和乙醇以Waters Suger—Park—1钙型阳离子交换柱为固定相,0．05g／L EDTA钙钠水溶液为流动相分离,示差折光仪为检测器检测测定。结果：一次进样可同时测定细菌发酵液样品中的糖、甘油和乙醇;方法RDS在0．52％-0．85％之间,标准回收率在99—102％之间,结果满意。结论：该方法简便、快速、结果可靠,为发酵法生产甘油过程中的质量监控提供了方法。     

L—苹果酸产生菌筛选及高产突变株诱变选育

通过广泛收集和分离,获得根霉属、曲霉属及裂褶菌属等属菌侏８９７侏。产酸指示平板上的变色圈测定结果表明,它们中间６２８株为产酸菌。通过纸层析对产酸菌发酵液酸谱的分析,获得１２９株Ｌ－苹果酸产生菌,经进一步测定发酵液中Ｌ－苹果酸的含量,筛选出以葡萄糖为原料,摇瓶发酵１４０小时,Ｌ－苹果酸产率４８．３７ｇ／Ｌ,对糖转化率４８．３７×１０＾－２的菌株ＬＭ０２。经初步鉴定,这一菌株为曲霉。以ＬＭ０２作为出发     

Investigation of the mechanism of temperature sensitivity of the electroreceptors of ampullae of lorenzini

In experiments on Black Sea skates (Raja clavata), the potential of the receptor epithelium of the ampullae of Lorenzini and spike activity of single nerve fibers connected to them were investigated during electrical and temperature stimulation. Usually the potential within the canal was between 0 and –2 mV, and the input resistance of the ampulla 250–400 k. Heating of the region of the receptor epithelium was accompanied by a negative wave of potential, an increase in input resistance, and inhibition of spike activity. With worsening of the animal's condition the transepithelial potential became positive (up to +10 mV) but the input resistance of the ampulla during stimulation with a positive current was nonlinear in some cases: a regenerative spike of positive polarity appeared in the channel. During heating, the spike response was sometimes reversed in sign. It is suggested that fluctuations of the transepithelial potential and spike responses to temperature stimulation reflect changes in the potential difference on the basal membrane of the receptor cells, which is described by a relationship of the Nernst's or Goldman's equation type.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. I. M. Sechenov, Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Pacific Institute of Oceanology, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Neirofiziologiya, Vol. 12, No. 1, pp. 67–74, January–February, 1980.     

Principles of organization and evolution of systems of regulation of functions

Evolution of living organisms is closely connected with evolution of structure of the system of regulations and its mechanisms. The functional ground of regulations is chemical signalization. As early as in unicellular organisms there is a set of signal mechanisms providing their life activity and orientation in space and time. Subsequent evolution of ways of chemical signalization followed the way of development of delivery pathways of chemical signal and development of mechanisms of its regulation. The mechanism of chemical regulation of the signal interaction is discussed by the example of the specialized system of transduction of signal from neuron to neuron, of effect of hormone on the epithelial cell and modulation of this effect. These mechanisms are considered as the most important ways of the fine and precise adaptation of chemical signalization underlying functioning of physiological systems and organs of the living organism