Endotoxin and cytokines in patients with gastrointestinal tract perforation

Plasma levels of endotoxin and various cytokines were assessed in 70 patients with gastrointestinal tract perforation. Sepsis developed in 29 of them, and eight of these (27.6%) had on admission endotoxin levels higher than 9.8 pg ml(-1). The clinical outcome correlated with the level of tumour necrosis factor alpha (TNFalpha), rather than with the endotoxin level. The high interleukin 6 (IL-6) level was shown in septic patients and no correlation was observed between the IL-6 level and the clinical outcome. Plasma TNFalpha levels tended to change independently from endotoxin levels, suggesting that TNFalpha may have been locally produced in inflammatory lesions.     

Responses of the photosynthetic flagellate,Euglena gracilis,to hypergravity

Motility and orientation has been studied in the unicellular photosynthetic flagellate, Euglena gracilis, using real time image analysis capable of tracking up to 200 cells simultaneously in the slow rotating centrifuge microscope (NIZEMI) which allows one to observe the cells' swimming behavior during centrifugation accelerations between 1 g and 5 g. At 1 g the cells show a weak negative gravitaxis, which increases significantly at higher accelerations up to about 3 g. Though most cells were capable of swimming even against an acceleration of 4.5 g, the degree of gravitaxis decreased and some of the cells were passively moved downward by the acceleration force; this is true for most cells at 5 g. The velocity of cells swimming against 1 g is about 10% lower than that of cells swimming in other directions. The velocity decreases even more drastically in cells swimming against higher acceleration forces than those at 1 g. The degree of gravitactic orientation drastically decreases after short exposure to artificial UV radiation which indicates that gravitaxis may be due to an active physiological perception rather than a physical effect such as an asymmetry of the center of gravity within the cell. Offprint requests to: D.-P. Häder     

Improved performance in viscous mycelial fermentations by agitator retrofitting

For viscous mycelial fermentations it was demonstrated at the pilot-plant scale that the replacement of standard radial flow Rushton turbines with larger diameter axial-flow Prochem hydrofoil impellers significantly improved oxygen transfer efficiency. It was also determined that the Streptomyces broth under evaluation is highly shear thinning. Separate experiments using a Norcardia broth with similar Theological properties demonstrated that the oxygen transfer coefficient, K(L)a, can be greatly increased by use of water additions to reduce broth viscosity. These observations are consistent with the hypothesis that the improvement in oxygen transfer by changing agitator types is primarily due to an improvement in bulk mixing. A model is presented, based on the concepts of Bajpai and Reuss, which explains this improvement in performance in terms of enlargement of the well mixed micromixer region for viscous mycelial broths.     

A new immobilization technique of whole cells and enzymes with colloidal silica and alginate

A mixed gel composed of colloidal silica and alginate (As gel) was prepared for the immobilization of enzymes or microorganisms. The physical strength of AS gel increased with the amount of colloidal silica. The ethanol production rate of Saccharomyces cerevisiae (IFO 0224) immobilized in AS gel was higher than in alginate gel (Al gel) in the early phase of growth. At a concentration of glucose of more than 10%, the ethanol production of immobilized yeast in AS gel was higher than in Al gel. Any difference was not recognized in the diffusion coefficient of glucose between AS and Al gels. The AS gel had an ability to retain proteins such as bovine serum albumin and gamma-globulin. The alkaline protease and beta-galactosidase in AS gel continued their function for a long time, but those immobilized in Al gel did not. Immobilized beta-galactosidase in AS gel had a higher thermal stability than in Al gel or free enzymes.     

Organosolv pretreatment for enzymatic hydrolysis of poplars: I. Enzyme hydrolysis of cellulosic residues

Aspen (Populus tremuloides) and black cottonwood (Populus trichocarpa) organosolv pulps produced in a wide range of solvent composition (between 30 and 70% by volume of methanol) and catalysts (H(2)SO(4) and H(3)PO(4)) such that the cooking liquor pH 相似文献   

Properties of invertase immobilized on the poly(ethylene-co-vinyl alcohol) hollow fiber membrane

Invertase was ionically immobilized on the poly(ethylene-co-vinyl alcohol) hollow fiber inside surface, which was aminoacetalized with 2-dimethylaminoacetaldehyde dimethyl acetal. Immobilization and enzyme reaction were carried out by letting the respective solutions pass or circulate through the inside of the hollow fiber, and the activity of invertase was determined by the amount of glucose produced enzymatically from sucrose. Immobilization conditions were examined with respect to the enzyme concentration and to the time, and consequently the preferable conditions at room temperature were found to be 5 mug/mL of enzyme concentration and 4 h of immobilization time. Under those conditions the immobilization yield and the ratio of the activity of the immobilized invertase to that of the native one were 89 and 80%, respectively. For both repeating and continuous usages, the activity fell to ca. 60% of the initial activity in the early stage and after that almost kept that value. The apparent Michaelis constant K(m) (') for the immobilized invertase decreased with increasing the flow rate of the substrate solution, to be close to the value for the native one. Furthermore, the possibility of the separation of the enzymatically formed glucose from the reaction mixture through the hollow fiber membrane was preliminarily examined.