一株产高质量浓度酒精酵母的间歇发酵动力学初步研究

对一株产高质量浓度酒精的酿酒酵母的间歇发酵动力学进行了初步研究.分别对基质、产物和菌体对时间的变化,所得回归方程显示,3个状态参量与时间呈对数关系;而后采用比生长速率、某一时段的菌体浓度、某一时段的葡萄糖质量浓度、某一时段的酒精质量浓度来描述整个发酵过程中菌体、基质和产物之间的关系,通过二次曲面回归得到了间歇发酵动力学数学模型,与传统的Monod模型和Logistic模型相比,该模型对试验数据拟合和预测性能较好.最后,用Simplex优化方法对间歇发酵动力学进行动态模拟,得到很好的拟合结果.将得到的模型参数用于预测初糖质量浓度为24.7g/dL的间歇发酵,预测结果也较好.因此,该模型可用来预测高初糖质量浓度下间歇发酵过程.     

利用神经网络对L-缬氨酸发酵建模

根据L-缬氨酸发酵过程的实验数据,利用BP神经网络进行训练,建立实验模型,实时获取生化变量的预测值并进行验证.结果表明,运用BP神经网络对L-缬氨酸发酵过程进行模拟,所建立的模型能比较精确地模拟菌体生长、底物消耗及发酵产酸过程的变化,可以为L-缬氨酸发酵生产过程提供动态模拟,具有重要的实用价值.     

鼠李糖脂分批式发酵动力学模型

根据3.7 L瑞士Bioengineer KLF2000型发酵罐分批发酵的实验数据,利用GraphPad Prism软件对假单胞菌BS-03产鼠李糖脂生物表面活性剂的发酵动力学模型进行非线性拟合,说明Logistic模型和L-P模型能较好的描述假单胞菌BS-03发酵过程中的菌体生长、鼠李糖脂合成和限制性基质的消耗动力学。     

pH值和初始淀粉质量浓度对发酵生产谷氨酰胺转胺酶的影响

研究了不同的 pH值对谷氨酰胺转胺酶 (MTG)发酵过程中菌体生长和产酶的影响 ,在此基础上探讨了不同初始淀粉质量浓度及中后期碳源流加对发酵过程的影响 .研究结果表明 :pH值对菌体的生长和产酶模式产生明显的影响 ,当发酵过程的 pH值控制在 6 .5时 ,最有利于菌体的生长和酶的合成 ,在此条件下可得到较高的菌体干重 (DCW )和酶活 ;初始淀粉质量浓度以 3g/dL较适宜 ,其DCW和MTG酶活最高 ,DCW为 2 5.1g/L ,酶活水平达 2 .94U /mL ;中后期采用流加碳源的策略使发酵时间比分批发酵最好水平缩短 12h左右 ,酶活提高到 3.0 5U/mL ,各项指标均比分批发酵最好水平有明显的提高 .     

短梗霉多糖分批发酵动力学模型

对短梗霉多糖分批发酵动力学进行了研究.基于Logistic方程和Luedeking-Piret方程分别建立了短梗霉多糖发酵过程菌体生长、产物合成及底物消耗随时间变化的数学模型,同时对实验值与模型进行了验证比较.结果表明,模型模拟计算结果与实验值能较好地吻合,该模型能较好地反映短梗霉多糖分批发酵的过程.     

pH值对聚唾液酸分批发酵的影响及补料发酵

研究了不同pH值对聚唾液酸发酵过程中菌体生长和产聚唾液酸的影响.发酵初期pH自然下降时有利于菌体生长,菌体生长对数期较长,最大菌体干重可达6.9g/L;发酵中后期pH控制在6.4时有利于聚唾液酸的延续合成,合成对数期比其它pH条件下的合成对数期延长了11h.动力学特性表现为部分相关模式,而在其它pH条件下,动力学特性表现为相关模式.对聚唾液酸的流加补料发酵进行了初步研究,最终使菌体干重达到11.16g/L,聚唾液酸产量达到2.606g/L.     

粪产碱杆菌在不同底物限制性条件下连续培养

为了提高菌体阶段菌体的生长密度、对分批发酵有一些优化指导作用,对菌体本身特性进行了研究.以葡萄糖、氯化铵分别为限制性底物,对粪产碱杆菌进行了连续培养,模拟了粪产碱杆菌在不同的营养条件下的发酵情况,并对连续培养特性和动力学性质进行了分析.结果表明:在葡萄糖限制条件下粪产碱杆菌的比生长速率与限制性底物浓度的关系符合Monod方程,建立了相应的模型方程;同时还建立了两种限制条件下的葡萄糖的消耗动力学模型;并对两种限制条件下的维持系数、菌体产率进行了比较.比较表明:葡萄糖限制对菌体产率的影响比氯化铵限制时大,在氯化铵限制条件下菌体产率最大为0.4 g/(h·L),而葡萄糖限制条件下菌体产率最大只为0.3 g/(h·L)左右;氯化铵限制条件下的维持系数是葡萄糖限制条件下的2倍,说明发酵过程中主要的维持消耗是在产胶期热凝胶的合成过程中.     

基于主元分析和模糊模型的链霉素发酵过程建模

基于主元分析和模糊模型 ,提出了一种简单而有效的链霉素发酵过程产物浓度的预报方法 .该方法采用主元分析压缩关联程度高且含有测量噪声的实际工业生产数据 ,筛选出影响产物浓度的主要过程变量 ,构造了模糊分段线性模型的产物浓度估计器 .与线性多元回归模型相比 ,模糊模型更适合作为间歇发酵过程的状态估计器 .     

红酵母类胡萝卜素发酵助剂的筛选及应用

研究了几种促进剂和前体对红酵母RY－98类胡萝卜素发酵的影响，从中选出了番茄汁、花生油和核黄素3种对红酵母生长及类胡萝卜素合成具有显著促进作用的发酵助剂，并确定了适宜的用量。应用试验和发酵过程动态分析表明，这3种发酵助剂增产效果明显。当同时添加番茄汁3mL/L、花生油1.2mL/L和核黄素3.5mg/L时，菌体量、类胡萝卜素质量分数和产量可分别比对照组提高39.4%、32.8%和85.1%，且对发酵过程菌体生长及生理代谢规律无不良影响。     

基于高密度培养的两阶段发酵技术生产热凝胶的研究

根据热凝胶发酵过程中不同时间和空间对氧传质的不同需求,实施两阶段发酵工艺:第1阶段在种子罐中实施高密度培养,第2阶段在2级发酵罐中稀释细胞密度,使微生物直接进入产胶阶段,同时解除氧传质对产热凝胶的限制作用,达到高强度发酵生产热凝胶的目的.通过对两阶段发酵工艺的构建和优化,结果表明该工艺较好地满足菌体生长和热凝胶合成对营养和氧传质的不同要求,热凝胶产量达到66 g/L,相对于分批发酵工艺产胶量提高了106%,比产胶速率提高了20%,并且在菌体生长阶段发酵规模比分批发酵缩小了75%,因此节约了能量,降低了功率消耗.     

Modulation of the microenvironment by growth factors regulates the in vivo growth of skeletal myoblasts

OBJECTIVES

To investigate the optimal microenvironment for efficient myoblast transplantation in vivo.

MATERIALS AND METHODS

The effects of co‐culture with growth factors, including basic fibroblast growth factor (bFGF), hepatocyte growth factor (HGF), insulin‐like growth factor‐I) and platelet‐derived growth factor (PDGF), on in vitro growth, migration and proteolytic activity of mouse skeletal myoblasts were investigated. Myoblasts were co‐injected with growth factors into the subcutis and bladder wall of nude mice, and its impact on the growth patterns of myoblasts in vivo assessed.

RESULTS

There was dose‐dependent stimulation of in vitro myoblast growth after treatment with each of the four growth factors, but bFGF induced the most marked increase in the growth of myoblasts. Treatment of myoblasts with all types of growth factors also resulted in a dose‐dependent increase in the in vitro migration of myoblasts, and PDGF had the most prominent effect on myoblast migration. Increased secretion of matrix metalloproteinase‐9 (MMP‐9) in myoblasts induced by growth factors was proportional to their increased migration capacity, which was partly inhibited by SB‐3CT, an inhibitor of MMP‐9. The in vivo growth of myoblasts was significantly enhanced by co‐injection with all types of growth factor into both the subcutis and bladder wall, but this effect was most marked 1 and 2 weeks after co‐injection with bFGF and PDGF, respectively. Furthermore, there was synergistic in vivo growth of myoblasts by co‐injection of both bFGF and PDGF compared with that achieved with either agent alone.

CONCLUSIONS

These findings suggest that modulation of the microenvironment using growth factors, particularly bFGF and PDGF, could provide the optimum condition for effective myoblast transplantation in vivo.     

Age and pattern of the onset of differential growth among growth plates in rats

Differential growth is the phenomenon whereby growth plates in the same individual at the same time all have uniquely different axial growth velocities. Differential growth is clearly present in the adolescent skeleton. In this study we ask two questions. When and by what pattern does the phenomenon of differential growth begin? Second, to what extent are the development of differential growth velocities correlated with changes in hypertrophic chondrocyte volume and/or with changes in chondrocytic production/turnover? Four growth plates (proximal and distal radial; proximal and distal tibial) were studied at 24 different time points in Long‐Evans rats between the 17th gestational day (when differential growth does not exist) and postnatal day 27 (when differential growth is well established). Growth velocities were measured using fluorochrome labeling. Using stereological methodology, multiple chondrocytic kinetic parameters were measured for all growth plates. Elongation of the proximal radial growth plate decreases relative to elongation in the other three growth plates in the late fetal phase. Differential growth is fully expressed at postnatal day 13 when the other three growth plates start to decrease daily elongation at different rates. Differential growth is primarily associated with differences in hypertrophic cell volume manifested when growth deceleration occurs. This study also illustrates that differential growth is superimposed on systemic regulators that affect all growth plates simultaneously. The most dramatic illustration of this is the sharp decline in growth velocity in all four growth plates that occurs perinatally. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1457–1465, 2008     

胫骨骨干端延长对胫骨生长板纵向生长的影响

[目的]研究胫骨骨干端截骨延长对胫骨生长板和纵向生长的影响。[方法]建立兔胫骨骨干端截骨和延长的动物模型;拍摄标准胫骨放射照片以测量其长度,胫骨远近端骨骺生长板做成组织切片以测量其厚度。[结果]胫骨中部骨干行单纯截骨后,增加胫骨纵向生长和胫骨远近端骨骺生长板的厚度,胫骨中部骨干行截骨延长后,胫骨纵向生长和胫骨远近端骨骺生长板的厚度没有改变。[结论]胫骨骨干截骨延长术不会妨碍胫骨的纵向生长。     

Growth potential of different zones of the growth plate—an experimental study in rabbits

Despite clinical efforts to treat growth disturbances only little is known about the growth potential of the different zones of the growth plate. The aim of this study was to investigate the growth potential of different zones of the growth plate. A total of 20 New Zealand White rabbits were used for this experiment. The right and left ulna of each animal were used resulting in a total of 40 ulnae. Animals were assigned into five groups. In groups I and II resection of the metaphyseal (n = 12) or the epiphyseal (n = 6) segment of the growth plate was performed. In group III resection of the growth plate and re‐implantation was performed (n = 6). In group IV the growth plate was resected and re‐implanted after a 180° rotation (n = 6). Animals in group V served as controls. Histologic and radiologic examinations were performed to evaluate the growth process at 1, 2, 4, and 12 weeks following surgery. In group I, III, and IV temporary growth disturbance which was compensated within a short time was observed. Resection of the epiphyseal part resulted in growth arrest of the distal ulna in combination with normal growth of the radius which led to and valgus deformity of the limb. The results of this study indicate the importance of the reserve zone for the functioning of the growth plate. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 30:162–168, 2012     

EGF-Related Peptides in the Pathophysiology of the Mammary Gland

Normal mammary gland development is the result of complex interactions between a number of hormones and growth factors. Normal and malignant human mammary epithelial cells are able to synthesize and to respond to various different, locally acting growth factors and growth inhibitors. Among these, the EGF-related peptides play an important role in regulating the proliferation and differentiation of human mammary epithelial cells. EGF⁴ and TGF are able to stimulate the lobulo-alveolar development of the mammary gland in vivo as well they are involved in the pathogenesis of human breast cancer. Experimental evidence suggests that estrogen-induced proliferation of breast carcinoma cells is mediated in part by EGF-related growth factors. It has also been demonstrated that activation of certain cellular protooncogenes such as c-Ha-ras in human mammary epithelial cells results in cellular transformation and in an increased production of several EGF-related growth factors such as TGF and amphiregulin. Coexpression of both EGF-related peptides and their own receptors frequently occurs in human breast carcinomas and in human breast cancer cell lines, suggesting that an autocrine pathway of uncontrolled cell growth sustains neoplastic transformation.     

模糊逻辑与腰腿痛的诊断

在现实世界中,许多问题的界限是不清晰的,甚至是很模糊的。人们为了实际的目的,需研究这些不清晰的,模糊的问题,使其清晰化,以获得有用的结果,这一研究中所使用的逻辑就是模糊逻辑。它最早应用在数学领域,又称弗晰逻辑(Fuzzy Iogic)是多值逻辑的一个新的研究领域。资料表明,1965年美国数学家扎德(Lotfi Asker Zadeh)研究了费晰集合,发展了弗晰逻辑。1966年P.N.Ma－rinos发表了关于模糊逻辑的内部研究报告,这是模糊逻辑诞生标志。古典的二值逻辑在具有二值特点的学科领域中能发挥巨大作用,但象在人工智能,生物工程,社会经济等复杂系统的研究中便显得无能为力,因为这些系统不但结构功能复杂,涉及大量参数和变量,而且往往具有不精确性的特点,而模糊逻辑却能适应这种研究的需要。     

脾切除对肝纤维化大鼠肝脏PDGF-B表达及血清PDGF-BB水平的影响

Objective To explore the effects of splenectomy on hepatic fibrosis and on the expression of PDGF-B in the liver and PDGF-BB in the serum of rats with hepatic fibrosis. Methods By hypodermic injection CCl4, we established 65 rat models with hepatic fibrosis, splenectomies were performed in the three groups at different phases: before hypodermic injection CCl4 (A group), five weeks after hypodermic injection CCl4 (B group), and ten weeks hypodermic injection CCl4 (C group). The control groups were established at the same time, with samples of the livers and serum of the rats taken in different phases. The expressions of PDGF in the liver were detected by immunohistochemistry technique and the degree of hepatic fibrosis was detected by HE staining. The serum levels of PDGF-BB were analyzed by ELISA technique. Results Absorbance values of PDGF-B in the experimental group were significantly lower than the control groups (P＜0. 05). Serum levels of PDGF-BB of the rats after splenectomy were significantly lower than those in the control groups (P＜0.05). HE and Masson's staining showed that the progression of Hepatic fibrosis was slow in the A group. Hepatic pathologic state was significantly relieved in the B group and the inflammation and fibrosis was relieved in the C group. Conclusion Earlier period splenectomy could delay the proceeding of experimental hepatic fibrosis. After splenectomy the decline in the level of PDGF may be one of the mechanisms causing the delay.