bluuebunny/crossref_metadata_2025 huggingface dataset:
Diabetes mellitus as a Risk Factor for Glaucomatous Optic Neuropathy
Authors: Nakamura Makoto , Kanamori Akiyasu , Negi Akira
Published: December 2004

Open-angle glaucoma (OAG) is an optic neuropathy characterized by progressive retinal ganglion cell (RGC) death and optic disk excavation. Evidence is accumulating that RGC apoptosis is the fundamental pathology of OAG. Among several risk factors for development and progression of OAG, inclusion of comorbid diabetes has been controversial. Some large population-based prevalence and incidence studies found a positive association between diabetes and OAG, whereas others did not. This inconsistency is derived from selection-, recall-, or survival-bias or misclassification due to low incidence of the two diseases. On the other hand, recent basic studies have shown that diabetes not only affects vascular tissues but also compromises neuronal and glial functions and metabolism in the retina, which ultimately gives rise to apoptotic death of retinal neurons including RGCs. The impaired metabolism of neurons and glia by diabetes may render RGCs susceptible to additional stresses related to OAG such as elevated intraocular pressure. In fact, our latest data demonstrate that retinas taken from rats with streptozotocin-induced diabetes, which underwent cauterization of three episcleral veins to become a chronic glaucoma model, had significantly more apoptotic cells than those from rats with diabetes alone or with chronic glaucoma alone. In this regard, diabetes is a ‘risk factor’ for glaucomatous optic neuropathy. Additionally, prospective studies are needed to determine if OAG patients with diabetes have a more aggressive course than those without diabetes.
Fixation Stability and Macular Light Sensitivity in Patients with Diabetic Maculopathy: A Microperimetric Study with a Scanning Laser Ophthalmoscope
Authors: Kube Thomas , Schmidt Stephanie , Toonen Frank , Kirchhof Bernd , Wolf Sebastian
Published: December 2004

Background: In patients with diabetic maculopathy, evaluation of visual acuity alone may not represent central retinal function sufficiently. Despite good visual acuity, patients may suffer from visual disturbances like waviness, relative scotoma, loss of fixation and decrease of contrast sensitivity. The aim of the study was to assess localized light sensitivity in the central visual field and to determine fixation stability in patients with diabetic maculopathy with moderate visual loss in comparison to healthy controls. Methods: Twenty-seven patients (mean age: 54 ± 15; range 17–81 years) with diabetic maculopathy and 61 controls (mean age: 45 ± 22; range 18–85 years) were included in the study. Light sensitivity was quantified by presenting stimuli with different light intensity with simultaneous real-time monitoring of the retina (intensity: 0–27.9 dB; size: Goldmann III, wavelength: 633 nm). Eye movements were controlled by semiautomatic fundus tracking. Fixation stability was quantified by measuring the area within 75% of all points of fixation. Results: Fixation stability was significantly decreased in diabetic patients in comparison to controls (43 ± 22 vs. 31 ± 16 arc min, p < 0.01). There was a significant difference in macular light sensitivity in diabetic patients compared to controls (19.6 ± 0.5 dB), both in mean difference (15.6 ± 1.4 dB) and if affected with macular edema (16.1 ± 4.5 dB), hard exudates (13.3 ± 6.7 dB), nonperfusion areas (10.3 ± 7.9 dB) and laser burns (3.0 ± 6.1 dB). Temporal parts of the macula were more affected than other parts. No correlation was found between visual acuity and foveal light sensitivity and foveal fixation, respectively. Conclusion: Macular light sensitivity decreased progressively with the kind and severity of retinal alteration independent of visual acuity. The assessment of macular light sensitivity and stability of fixation with automatic threshold microperimetry may help to identify patients with diabetic maculopathy and could improve the management of diabetic maculopathy.
Comparison of Tilt and Decentration between Phacoemulsification and Phacotrabeculectomy
Authors: Mutlu Fatih Mehmet , Bayer Atilla , Erduman Cüneyt , Bayraktar Mehmet Zeki
Published: December 2004

Purpose: To determine the extent of intraocular lens (IOL) tilt and decentration values after combined surgery in patients with cataract and glaucoma. Materials and Methods: A total of 106 cataractous eyes undergoing IOL implantation were divided into 2 groups. Group 1 comprised 42 eyes undergoing phacotrabeculectomy surgery for cataract and primary open-angle glaucoma (POAG), and group 2 comprised 64 eyes undergoing phacoemulsification surgery for senile cataract. The length of IOL decentration and the angle of IOL tilt were quantitated by using Purkinje reflections and photographic documentation. Results: The differences regarding both the IOL tilt (2.84 ± 0.37; 2.97 ± 0.37, respectively) and decentration (0.39 ± 0.27; 0.49 ± 0.35, respectively) was insignificant (p > 0.05) between groups. Conclusion: There is no increased effect of phacotrabeculectomy on tilt and decentration of IOLs in eyes with POAG when compared with eyes which underwent phacoemulsification surgery.
Hyperphosphatemia in Renal Failure
Authors: Ritz Eberhard , Gross Marie-Luise
Published: December 2004

The recent recognition that hyperphosphatemia is a strong predictor of survival on dialysis has rekindled interest in the regulation and control of serum phosphate. In incipient renal failure hyperphosphatemia is prevented by increased fractional renal phosphate excretion mediated via an increase in parathyroid hormone and the novel phosphaturic hormone FGF-23 (and possibly others). At a glomerular filtration rate of approximately 30 ml/min this compensatory mechanism fails and hyperphosphatemia ensues. Pre-dialytic serum phosphate concentrations of >6 mg/dl increase cardiac mortality presumably to a large extent, but not exclusively, via promoting vascular calcification. It has recently been recognized that vascular calcification is not only a passive precipitation process following transgression of the critical Ca-×-P product, but is an active process accompanied by expression of osteoblastic bone markers in the vessel wall. Because of the recent recognition of the relation between vascular calcification and serum phosphate as well as serum calcium, there is a need for novel calcium-free phosphate binders. Currently sevelamer and lanthanum carbonate have been introduced and trivalent iron preparations are under development.
Vascular Access Monitoring Improves Outcomes
Authors: Sands Jeffrey J.
Published: December 2004

Vascular access monitoring can identify patients at increased risk of future access thrombosis. When coupled with a program of elective stenosis correction, access thrombosis rates decline approximately 50–75%. This results in arteriovenous (AV) fistula thrombosis rates of 0.1–0.2/patient year (vs. 0.2–0.4 at baseline) and AV graft thrombosis rates <0.5/patient year (vs. 0.8–1.2 thromboses/patient year at baseline). Evaluating the long-term impact on access survival remains problematic. There are no large-scale randomized trials and existing studies exhibit marked differences in target populations, clinical protocols and outcome definitions. Differences in payment systems also significantly influence the efficacy of monitoring and intervention programs. Despite these challenges, the current data support the K/DOQI recommendations that all patients undergo a program of regular access monitoring preferably by access flow measurement coupled with prompt imaging and elective stenosis correction for low flow accesses.
Methodological Issues in Clinical Trials of Antidepressant Medications: Perspectives from Psychotherapy Outcome Research
Authors: Gaudiano Brandon A. , Herbert James D.
Published: December 2004

Despite their widespread use, the specific efficacy of antidepressant medications has been a source of debate in recent years. Examination of the literature reveals that a significant proportion of the benefit produced in antidepressant trials is duplicated in pill placebo conditions. Furthermore, early trials utilizing active placebos, or medications that mimic the common side effects of antidepressants, showed even smaller differences as compared with active medications. We examine issues surrounding the use of placebo control conditions in antidepressant trials, including the pros and cons of active placebos. We conclude that similar challenges are faced by psychotherapy outcome researchers who have focused more on the separation of specific from nonspecific treatment factors and on the effects of researcher allegiance and patient expectancy on outcome. Within this context, recommendations for improving future antidepressant research are discussed.
Autonomic Function Assessed by Heart Rate Variability Is Normal in Alzheimer’s Disease and Vascular Dementia
Authors: Allan L.M. , Kerr S.R.J. , Ballard C.G. , Allen J. , Murray A. , McLaren A.T. , Kenny R.A.
Published: December 2004

Heart rate variability (HRV) is a sensitive method for the assessment of autonomic function and requires little cooperation from the subject, making it suitable for use in dementia. Preliminary studies have suggested that HRV may be impaired in Alzheimer’s disease (AD). HRV has not been studied in vascular dementia (VAD). We investigate autonomic function in AD and VAD, using power spectral analysis of HRV. One hundred and fourteen participants were evaluated (14 AD, 20 VAD and 80 controls). The resting ECG was recorded for 5 min with participants in the supine position. Power spectral analysis used to obtain spectral bands in the very-low-frequency (<0.04 Hz), low-frequency (0.04–0.15 Hz) and high-frequency (0.15–0.40 Hz) bands and total spectral power (<0.40 Hz) according to international HRV guidelines. There were no differences in HRV in patients with AD or VAD when compared with controls.
Platelet-Derived Growth Factor-BB–Induced Human Smooth Muscle Cell Proliferation Depends on Basic FGF Release and FGFR-1 Activation
Authors: Millette Esther , Rauch Bernhard H. , Defawe Olivier , Kenagy Richard D. , Daum Guenter , Clowes Alexander W.
Published: December 2004

We have shown that the G protein–coupled receptor (GPCR) agonists, thrombin and Factor Xa, stimulate smooth muscle cell (SMC) proliferation through transactivation of the EGF receptor (EGFR) or the FGF receptor (FGFR), both of which are tyrosine kinase receptors. In the present study, we investigated whether platelet-derived growth factor (PDGF), a tyrosine kinase receptor agonist, might transactivate another tyrosine kinase receptor to induce SMC proliferation. Because heparin inhibits PDGF-mediated proliferation in human SMCs, we investigated whether the heparin-binding growth factor basic fibroblast growth factor (bFGF) and one of its receptors, FGFR-1, play a role in the response of human arterial SMCs to PDGF-BB. PDGF-BB induced the release of bFGF and sustained phosphorylation of FGFR-1 (30 minutes to 6 hours). A bFGF-neutralizing antibody inhibited PDGF-BB–mediated phosphorylation of FGFR-1, DNA synthesis, and cell proliferation. In the presence of bFGF antibody, PDGF-BB–induced early activation of ERK (0 to 60 minutes) was not affected, whereas late ERK activation (2 to 4 hours) was reduced. When FGFR-1 expression was suppressed using small interfering RNA (siRNA), ERK activation was reduced at late, but not early, time points after PDGF-BB stimulation. Addition of bFGF antibody to cells treated with siRNA to FGFR-1 had no further effect on ERK activation. Our results provide support for a novel mechanism by which PDGF-BB induces the release of bFGF and activation of FGFR-1 followed by the sustained activation of ERK and proliferation of human SMCs.
The Zonal Asymmetry of the Southern Hemisphere Winter Storm Track
Authors: Inatsu Masaru , Hoskins Brian J.
Published: December 2004

Atmospheric general circulation model experiments have been performed to investigate how the significant zonal asymmetry in the Southern Hemisphere (SH) winter storm track is forced by sea surface temperature (SST) and orography. An experiment with zonally symmetric tropical SSTs expands the SH upper-tropospheric storm track poleward and eastward and destroys its spiral structure. Diagnosis suggests that these aspects of the observed storm track result from Rossby wave propagation from a wave source in the Indian Ocean region associated with the monsoon there. The lower-tropospheric storm track is not sensitive to this forcing. However, an experiment with zonally symmetric midlatitude SSTs exhibits a marked reduction in the magnitude of the maximum intensity of the lower-tropospheric storm track associated with reduced SST gradients in the western Indian Ocean. Experiments without the elevation of the South African Plateau or the Andes show reductions in the intensity of the major storm track downstream of them due to reduced cyclogenesis associated with the topography. These results suggest that the zonal asymmetry of the SH winter storm track is mainly established by stationary waves excited by zonal asymmetry in tropical SST in the upper troposphere and by local SST gradients in the lower troposphere, and that it is modified through cyclogenesis associated with the topography of South Africa and South America.
Simulation of Late-Twenty-First-Century Changes in Wintertime Atmospheric Circulation over Europe Due to Anthropogenic Causes
Authors: Terray Laurent , Demory Marie-Estelle , Déqué Michel , de Coetlogon Gaelle , Maisonnave Eric
Published: December 2004

Evidence is presented, based on an ensemble of climate change scenarios performed with a global general circulation model of the atmosphere with high horizontal resolution over Europe, to suggest that the end-of-century anthropogenic climate change over the North Atlantic–European region strongly projects onto the positive phase of the North Atlantic Oscillation during wintertime. It is reflected in a doubling of the residence frequency of the climate system in the associated circulation regime, in agreement with the nonlinear climate perspective. The strong increase in the amplitude of the response, compared to coarse-resolution coupled model studies, suggests that improved model representation of regional climate is needed to achieve more reliable projections of anthropogenic climate change on European climate.
Detection of Liver Metastases From Endocrine Tumors: A Prospective Comparison of Somatostatin Receptor Scintigraphy, Computed Tomography, and Magnetic Resonance Imaging
Authors: Dromain Clarisse , de Baere Thierry , Lumbroso Jean , Caillet Hubert , Laplanche Agnès , Boige Valerie , Ducreux Michel , Duvillard Pierre , Elias Dominique , Schlumberger Martin , Sigal Robert , Baudin Eric
Published: December 2004

Purpose

To compare the respective sensitivity of somatostatin receptor scintigraphy (SRS), computed tomography (CT), and magnetic resonance imaging (MRI) in the detection of liver metastases from well-differentiated gastroenteropancreatic endocrine tumor (WDGEP ET) patients. To define predictive factors for “high-sensitivity SRS.”

Patients and Methods

Sixty-four patients with WDGEP ET underwent SRS with abdominal single-photon emission computed tomography (SPECT), spiral CT, and 1.5-T MRI within a 15-day interval, the order of which was randomized. Two readers analyzed images of each modality, blindly and independently.

Results

Hepatic metastases were present in 40 of the 64 patients and confirmed by pathology after liver biopsy or surgery in 32 and eight patients, respectively. SRS, CT, and MRI detected a total of 204, 325, and 394 metastases, respectively. The number of detected metastases was significantly higher with MRI than with CT (P = .02) and SRS (P < 10−4) and higher with CT than with SRS (P < 10−4). SRS was negative in seven patients with a positive CT and/or MRI. More lesions were detected in 10 patients by SPECT compared with static views. The median metastasis size was significantly correlated (P = .04) with the sensitivity of SRS.

Conclusion

MRI seems to have an edge over CT and SRS for the detection of liver metastases from endocrine tumors. We recommend the systematic performance of liver MRI at WDGEP ET initial staging and before major therapeutic events. The low performance of SRS was mainly explained by the impact of the metastasis size on the detection capacity of SRS.
Tumoral Drug Metabolism: Overview and Its Implications for Cancer Therapy
Authors: Michael M. , Doherty M.M.
Published: December 2004

Drug-metabolizing enzymes (DME) in tumors are capable of biotransforming a variety of xenobiotics, including antineoplastics, resulting in either their activation or detoxification. Many studies have reported the presence of DME in tumors; however, heterogenous detection methodology and patient cohorts have not generated consistent, firm data. Nevertheless, various gene therapy approaches and oral prodrugs have been devised, taking advantage of tumoral DME. With the need to target and individualize anticancer therapies, tumoral processes such as drug metabolism must be considered as both a potential mechanism of resistance to therapy and a potential means of achieving optimal therapy. This review discusses cytotoxic drug metabolism by tumors, through addressing the classes of the individual DME, their relevant substrates, and their distribution in specific malignancies. The limitations of preclinical models relative to the clinical setting and lack of data on the changes of DME with disease progression and host response will be discussed. The therapeutic implications of tumoral drug metabolism will be addressed—in particular, the role of DME in predicting therapeutic response, the activation of prodrugs, and the potential for modulation of their activity for gain are considered, with relevant clinical examples. The contribution of tumoral drug metabolism to cancer therapy can only be truly ascertained through large-scale prospective studies and supported by new technologies for tumor sampling and genetic analysis such as microarrays. Only then can efforts be concentrated in the design of better prodrugs or combination therapy to improve drug efficacy and individualize therapy.
Practitioners As Experts: The Influence of Practicing Oncologists “in-the-Field” on Evidence-Based Guideline Development
Authors: Browman George P. , Makarski Julie , Robinson Paula , Brouwers Melissa
Published: December 2004

Purpose

Panels of experts are used to develop clinical practice guidelines (CPGs) intended to be used by practitioners “in-the-field.” Therefore, oncologists’ participation in CPG development is an important strategy to promote CPG adoption. The purpose of this study was to evaluate the contributions of oncologists in-the-field to evidence-based CPG development using data from Ontario’s cancer system.

Methods

CPG development in Ontario includes surveys of oncologists’ opinions, using a structured questionnaire, about draft recommendations that were developed from rigorous systematic reviews of evidence prepared by expert panels. Two research assistants reviewed background documents to trace the changes in CPG recommendations from draft to final stage to determine the contribution of oncologists’ input to final recommendations. Changes to recommendations were categorized as either substantive (content or tone) or minor (ideas clarification or edits).

Results

From 2000 to 2003, 43 CPGs were developed. There were 87 changes to draft recommendations for 31 CPGs, of which 40 changes to 19 CPGs could be attributed to survey input from practicing oncologists. Of the 40 changes, 28 (70%) were judged to be substantive.

Conclusion

Despite a rigorous evidence-based process for CPG development, practicing oncologists contribute substantially to the final recommendations approved by the expert panel. It is hypothesized that the responsiveness of expert panels to input from oncologists in-the-field will facilitate adoption of CPGs.
Entwicklung und Toxinbildung von Aspergillus flavus im Festbettreaktor/Füllkörperreaktor
Authors: Kopp B. , Ehm H.‐J.
Published: December 2004

The behaviour of the mycelium forming mold Aspergillus flavus in packed column culture in comparison to conventional fermentation systems (surface culture and submerged culture) was investigated. The formation of aflatoxin was observed as a marker for the metabolic activity. The results demonstrated that the packed column system is situated with regard to the conditions of cultivation of mycelia forming molds between the surface culture and the submerged culture.
Immobilisierung mikrobieller Zellen und deren Nutzung zur Substratwandlung — Eine Literaturstudie
Authors: Berger R.
Published: December 2004

A review is given of most of the literature concerning the immobilization of whole microbial cells and their testing for application in product synthesis. The review includes a discussion of adventages and disadventages of immobilized cells, methods of immobilization, pretreatments, aftertreatments, operation, recent developments, and other problems together with a table of the immobilized microbes and the tested reactions of product synthesis, with 350 references.
Einfluß extracellulärer Konzentrationen auf die spezifische Wachstumsrate von Mikroorganismen
Authors: Schneider J. D.
Published: December 2004

The influence of extracellular concentrations of hydrogen ion and C‐substrates on the specific growth rate of different microorganisms is investigated.

A general relationship in the form

can be used to describe the inhibition effect of HPlus;‐ or substrate concentration (ci) on the growth rate. Different examples are demonstrated and the adequate specific constants K1 and K2 calculated.
Verfahrenstechnische Grundlagen der Reaktorgestaltung
Authors: Zlokarnik M.
Published: December 2004

Starting with the definition of the process term kLa, steady state and nonsteady state measuring methods are described for its determination. Then the sorption characteristics for mixing vessels and for bubble columns are presented with respect to the coalescence behaviour of the system treated. They permit the scale‐up of these devices and the optimization of their process parameters for a required oxygen uptake. In addition to the sorption characteristics for the given system the knowledge of the flooding point and the power characteristics is necessary for the lay‐out of mixing vessels, whereas in the case of bubble columns the gas hold‐up characteristic needs to be known.
Methylglyoxal — ein toxisches Fermentationsprodukt
Authors: Hofmann K. H. , Babel W.
Published: December 2004

Methylglyoxal (CH3COCHO) is a toxic intermediate of the carbon metabolism. Its accumulation in the growth medium of microorganisms may be an important danger for many fermentation processes. In this paper data will be presented which show the physiological effect of this compound on the living cell, the enzymes responsible for the synthesis and the turnover of methylglyoxal including the environmental conditions necessary for the accumulation of lethal concentrations in the medium.
Use of biorhythmic processes for increasing the efficiency of carbon‐compound conversion by microorganisms
Authors: Heinritz B. , Rogge G. , Stichel E. , Bley Th.
Published: December 2004

Fermentation kinetic, thermokinetic and morphological investigations of biological carbonsource conversions into microbial biomass and other reaction products can be used for improving the efficiency of biotechnical processes. In this way biorhythmic processes on a macrosocopic scale could be found in transitional stages of microorganism cultivation. These biorhythmic processes can be explained by the occurence of different cell states in the cell cycle. In order to characterize these cell states synchronized microorganism growth was investigated with the aid of the phased culture method. Two states could be observed in the case of yeast growth: the single cell state and the budding cell state. The duration and efficiency of the single cell state is dependent on the growth limitation and the carbon substrate feeding.

Thus the reduction of carbon substrate feeding in states of synchronized populations which are characterized by a high percentage of single cells and by energy metabolite production which, in turn, is influenced by carbon substrate concentration can cause increased material and energetic efficiencies of biological carbon‐source conversions.
Isolierung von Cytochrom P‐450 und des entsprechenden Reductasesystems aus Acinetobacter calcoaceticus
Authors: Asperger O. , Müller R. , Kleber H.‐P.
Published: December 2004

Cytochrome P–450 is found in soluble as well as in particulate fractions of n‐alkane‐induced cells of Acinetobacter calcoaceticus EB 104 as shown by differential centrifugation and; gelfiltration experiments. It is reduced by NADH in the presence of at least two soluble proteins. Particulate cytochrome P–450 was extracted by Triton X‐100 and purified to homogeneity. The 80 fold enrichment resulted in a content of 19.0 nmol cytochrome P‐450/mg protein. The maxima of the absolute spectra are 417 nm for the oxidized, 408 nm for the reduced and 448 nm for the CO complex of reduced cytochrome. A ferredoxin, identified by maxima of 415 and 460 nm in the absorption spectrum of the oxidized form and by the occurrence of acid‐labile sulfur, as well as a corresponding NADH‐dependent ferredoxin reductase were isolated independently from the same bacterial strain. Enzymatic reduction of purified cytochrome P–450 is mediated by these proteins, which are discussed as in vivo components of the cytochrome P–450 system of A. calcoaceticus EB 104.
Einfluß von Kupfer‐, Mangan‐ und Zinkionen auf die makromolekulare Zusammensetzung der Hefe Candida utilis M 72
Authors: Schneider J. D. , Faulhaber E. , Ringpfeil M.
Published: December 2004

The ions of Cu2+, Zn2+ and Mn2+ affect significantly the macromolecular composition of yeast Candida uiilis M 72. Crude protein and nucleic acid content increase and carbohydrate content decreases with rising intracellular ion concentration. Lipid fraction is influenced by metallic ions only little.

The correlation between intracellular ion concentration and cell composition of macromolecules can be described by simple equations.
Automatic computer control of fermentation processes
Authors: Balzer D. , Hesse J. , Schmidt A.
Published: December 2004

The application of an optimization algorithm to fermentation processes is described, which is based on information received by means of cascading the input quantities with pseudo random binary signals. The results in optimization of temperature, pH‐value as well as productivity are presented and discussed.
Entwicklung von Berechnugsmodellen für Enzymreaktoren (Teil 2)
Authors: Setzermann U. , Vondran J. , Mohr K.‐H.
Published: December 2004

Based on the partial differential equations for the transport of enthalpy and material a calculation model for the examination of the change of temperature and concentration in axial and radial direction was developed for the continuously working enzyme reactors. The pecularity of the kinetics of processes which are catalyzed by enzymes was considered due to the reaction velocity in modelling. In order to induce the numeric solution, an explicit method of differences was selected, the applicability of which was proved under consideration of appropriate initial and marginal conditions.
Laccase production by polyporus versicolor on different substrates
Authors: Sandhu D. K. , Arora D. S.
Published: December 2004

Extracellular production of laccase (E.C. 1.10.3.2) by Polyporus versicolor was studied on lignin, complex and defined media. Although the production of enzyme was more on lignin the specific activity was more on malt extract. Laccase was produced on all the media tested i.e. phenolic compounds, lignins and sugars alone, and in combination with malt extract, excepting salicylic acid. On single source media maximum yields of enzyme were obtained on polyfon followed by resorcinol, reax and lignin. As compared to phenolic compounds the enzyme production was low on sugars. Addition of malt extract enhanced the enzyme yield which was maximum in the case of lignin followed by gallic acid.
Utilization of cellobiose and production of β‐clucosidase by nine yeast species
Authors: Sandhu D. K. , Mondal D. , Sidhu M. S.
Published: December 2004

A comparative study of 9 yeasts namely, Candida blankii,C.humicola,C.ishiwadae,C.rhagii,C.tropicalis,Hensenula subpelliculosa,Saccharomyces cerevisiae,Trichosporon cutaneum and Tr.pullulans was carried out for the production of extracellular and cell bound β‐glucosidase using cellobiose as the substrate. Trichosporon cutaneum was found to be the best extracellular as well as cell bound β‐clucosidase producer and the former activity was more than the latter. In the rest of the yeasts most of them showed more cell bound β‐glucosidase as compared to the extracellular.
Mikrocomputer‐unterstützte prozeßkontrolle in der fermentationstechnik
Authors: Bayer K.
Published: December 2004

Nowadays computer control is an effective and well established tool in optimizing fermentation processes.

Based on recent development in microelectronics, especially in the field of personal computers, cost effective applications of this technology are now possible, even on laboratory‐ and pilot scale. In this paper the application of a personal computer (CBM 3032), controlling various types of fermentations, is described.

In more detail the availability of physiologically relevant sensors, especially the respiration and the dynamic calorimetry, are discussed.

Finally some examples of practical realisations are presented.
Rechnergestützte Führung von fermentationsprozessen teil III
Authors: Prause M. , Schulz H.‐J. , Wagler D.
Published: December 2004

In the second part of the publication [1] the application of an adaptive algorithm for the adaptation of the static optimum was orientated on a specific problem.

In this third part the indirect determination of the productivity from the nitrogen balance used in the adaptive algorithm is supplied, and control algorithms founded on the nitrogen balance are given in order to complete the algorithm.
Mikrobiologische Reaktionsabläufe beim AB‐Verfahren
Authors: Böhnke B.
Published: December 2004

At a comparable sludge loading of the second activation stage of the AB‐unit, in comparison with conventional one‐stage units for waste‐water cleaning, higher process stability and better quality outlet‐results are obtained

These results could be confirmed both in pilot units and in industrial plańnts.
Fehlermöglichkeiten der Gelöstsauerstoffmessung beim Betrieb von Bioreaktoren
Authors: Stottmeister U.
Published: December 2004

A review of errors, which can influence the measured data of electrochemical oxygen sensors (OS) in fermentation technique is presented.

The specifities of various sensor constructions are pointed out. References are given for selection of sensors to application in fermenters. Influences on the measured values can take place by fermentation conditions, arrangement of sensors in the fermenter and composition of the fermentation broth. The oxygen measurement in the multi‐phase system of fermentation fluids can cause a remarkable deviation of the measured values to the real ones.

Practical hints are given for use, calibration and sterilization of OS. Restricting conditions for measurements with this sensors are enumerated.
Kultivierung von isogenen E. coli‐Stämmen
Authors: Heinritz B. , Rogge G. , Ringpfeil M.
Published: December 2004

The strains E. coli C 600 and E. coli C 600 pL CR 665‐58 were cultivated on a glucose containing nutrient medium. The cell states of the cell cycle were investigated by means of phased cultivation. The doubling time and the specific carbon‐substrate consumption of cells were higher when E. coli C 600 pL CR 665‐58 was used. During cell doubling cell states characterized by different specific carbon‐substrate consumption coefficients were observed.

By adaptation of carbon‐substrates supply to the repetitive cell states during continuous cultivation of synchronized bacteria populations the efficiency of cell‐mass production was increased by 15 percent.
Physiological adaption in the synthesis of the extracellular polysaccharide xanthan
Authors: Behrens U. , Fiedler S. , Stottmeister U.
Published: December 2004

Xanthan overproduction only takes place if a sugar which may serve as precursor is present and transition to limited growth occured. This transient phase is characterized by a change in composition of macromolecular cell components (RNA, protein, carbohydrates). During the transient phase nearly no nitrogen is consumed, whereas glucose and oxygen consumption proceeds nearly undisturbed. The changes observed in the transient phase are discussed in context with physiological adaption.
Autolysis in yeasts
Authors: Babayan T. L. , Bezrukov M. G.
Published: December 2004

The term “autolysis” was introduced into biological literature by SALKOVSKY [1]. Ever since it began to be used to designate self‐digestion of cells under the action of their own intracellular enzymes. This definition is sufficiently satisfactory with regard to bacteria, and there are published lots of original and review papers dealing specifically with bacteria. Considerably less material has been accumulated on eukaryotes, apparently due to the absence of the fact of the cell self‐digestion in most yeasts.
Influence of carbon dioxide solubility on the accuracy of measurements of carbon dioxide production rate by gas balance technique
Authors: Minkevich I. G. , Neubert M.
Published: December 2004

The total amount of carbon dioxide (CD) produced by a microbial culture is evolved via an outlet gas stream, outflowing broth, and can lead to a rise of the CD content in broth. To analyze relations among the three amounts, the equilibrium is considered between different ionic forms of carbon dioxide at different pH values as well as between the gaseous and disolved CO2. Dependences of the equilibrium constants on temperature are found by a thermodynamic analysis. Numerical estimation of an error of the CD production rate measurement, originating from the neglect of dissolved CD, is developed. The gas analysis technique alone provides a sufficient accuracy at pH lower than 6. At higher pH the error can be estimated using equations presented below.
Inhibierungserscheinungen bei der alkoholischen Gärung, II. Einfluß der Substratkonzentration auf die spezifische Ethanolbildungsgeschwindigkeit von Saccharomyees cerevisiae
Authors: Richter K. , Becker U.
Published: December 2004

The influence of sucrose concentration on the specific ethanol production rate was studied during batch processes using the yeast strain Saccharomyces cerevisiae Hansen Sc 5. From experimental data a model could be derived for the simulataneous effect of substrate and product inhibition. It was found that both the decreases of fermentation activity of the cells caused by sucrose and ethanol have an additional relation to each other. This model also takes into consideration the fact that the maximum ethanol concentration P′ can't be realized at high substrate concentrations in a batch process. Compared to it sucrose concentrations below 100 g/l did not inhibit the ethanol production by the strain used in this investigation.
Meßeinrichtung zur kontinuierlichen Bestimmung flüchtiger organischer Substanzen in wäßrigen Medien
Authors: Hanschmann G. , Geppert G.
Published: December 2004

After a short review over methods for continuous determination of alcohols (methanol or ethanol) in fermentation liquids the working principle of a measuring device is described. With this apparatus preferentially low concentrations in the ppm‐range can be measured, but it is also suitable for higher concentrations without the necessity of sample dilution. Indication is linear over a wide range. Finally some experiences with the practical use of the instrument are given.
Wirkung von Ölen und Fettsäuren auf Wachstum und Enzymbildung bei Thermoactinomyees vulgaris. V. Untersuchungen zur Metabolisierung des Öles
Authors: Leuchtenberger A. , Ruttloff H.
Published: December 2004

The splitting of vegetable and animal oils used as antifoam agents and the metabolization of fatty acids released were analysed during fermentation of T. vulgaris in a 30 l jar fermenter. During cultivation time of 22 hours the oil amount decreased by 60 to 70%. The metabolization of fatty acids is 50 to 90% of the starting level depending on the kind of acid. The eventual effect of the fatty acids released from antifoam oils on the protease production is discussed.
Analytik Atypischer Fettsäuren in biologischen Matrizes
Authors: Pöurschmann J. , Pörschmann S. , Liebetrau L. , Richter K.
Published: December 2004

By combined application of chemical pretreatments, capillary gas‐chromatography and mass spectrometry it was possible to enlighten the structure of atypical fatty acids with hydroxy groups and cyclopropane rings under the use of only a few of reference substances.

The direct alkaline saponification of the sample with liberation of fatty acids and following methylation with boron trifluoride/methanol or diazomethane was proved to be the best method regarding to precision and speed of the sample cleanup.
Production of a white wine and a protein‐rich soy flour by yeast fermentation of soybean slurry, soybean milk and the whey from tofu production
Authors: Yee V. , Wellington G. H. , Olek A. , Steinkraus K. H.
Published: December 2004

A dry white wine with an alcoholic content of 10 to 14% v/v was produced by yeast fermentation of slurried ground soybeans, soybean milk and whey from tofu production. Wines from whey and soybean milk were judged by a 20 member taste panel to be acceptable and comparable to a commercial chablis control. Chemical analysis indicated that the high fat and protein contents of soybeans do not cause a problem in the production of wines from soybeans as the lipids and proteins are precipitated by the acid and alcohol formed during the fermentation. The less recovered following fermentation were dehydrated and ground to a flour having an enriched protein content due to the yeasts and an improved flavor resulting from the yeast fermentation.
Microbiological solubilization of metals from complex sulfide ore material in aerated column reactors
Authors: Puhakka J. , Tuovinen O. H.
Published: December 2004

Finely ground ore material (90%–200 mesh) was subjected to acid microbiological leaching in 20% and 30% (wt/vol) suspensions. The rate of aeration was maintained at 2 and 4 1/min · 1. After the onset of the microbiological phase of leaching, the solubilization of iron was initially rapid but was succeeded by Fe(III) precipitation. Major differences were apparent between inoculated and uninoculated suspensions for each metal analyzed (Fe, Al, Co, Cu, Ni, Zn). The sulfur balance in leach residues indicated elevated levels of elemental S and sulfate in the inoculated systems.
Sorption von Cellulase an Weizenstroh und seine Komponenten
Authors: Schulz G. , Hirte W. , Jacoplan V. , Philipp B.
Published: December 2004

By comparing different activity data of the buffered cellulase solution before and after contact with the substrate the interaction between Penicillium janthinellum cellulase and wheat straw, resp. its components (holocellulose and isolated lignin) has been investigated. The loss of activity due to sorption or denaturation has been found to differ widely between the different activity data and between the various substrates. A remarkable loss of enzyme activity was observed after contact with isolated straw lignin. The differences in activity decrease between the cellulose and the lignin moiety were found to be largent with the cellobiase activity.
Immobilized glucose dehydrogenase for cofactor regeneration in heme‐catalyzed demethylation and hydroxylation reactions
Authors: Kirstein D. , Kühn; M. , Schubert F. , Pohr P. , Scheller F.
Published: December 2004

Glucose dehydrogenase (E.C. 1.1.1.47) from B. megaterium M 1286 was immobilized together with mutarotase (E.C. 5.1.3.3) on several organic carriers and by different methods. The storage stability of the enzyme at pH‐values > 6 is slightly improved by immobilization and the pH‐optimum is shifted from 8.3 to 8.0. Kinetic constants of the immobilized enzyme are: K′M(NAD+) = 5.36 × 10−4 mol/l K′M(glucose) = 3.76 · 10−2 mol/l and V′max = 5.54 · 10−5 mol/(l min g carrier) for the most active preparation (2.16 mg enzyme/g carrier).

In reactor experiments the immobilized glucose dehydrogenase was used with glucose to regenerate NADPH in NADPH‐dependent iron‐III‐protoporphyrin‐IX‐imidazole catalyzed hydroxylation and demethylation of model substrates of cytochrome P‐450.

The advantages of the coupling of both reactions with cofactor recycling are shown and discussed.
Degradation of lignocellulosic residues by polyporus versicolor and the effect of moisture contents and phenolic compounds
Authors: Arora D. S. , Sandhu D. K.
Published: December 2004

Polyporus versicolor was selected to find out its ability to degrade four different lignocellulosic residues (angiospermic wood sawdust, sugarcane bagasse, paddy and wheat straw) under semisolid conditions. The production of laccase was also studied on these substrates. Sawdust suffered a maximum lignin loss though overall reduction in weight was maximum in paddy straw. Addition of malt extract and certain phenolic compounds (gallic acid, tannic acid and orcinol) favoured ligninolysis in sawdust. A moisture level of 5 ml/g of sawdust was found to be the most suitable for degradation whereas laccase yield increased with further rise in moisture content.
Rolle der einzelnen Komponenten des Cellulasekomplexes bei der Hydrolyse unlöslicher Cellulose
Authors: Klyosov A. A. , Kude J. , Goldstein G. Ch. , Meyer D.
Published: December 2004

The kinetics of the hydrolysis of microcrystalline cellulose (MC) by a Trichoderma reesei cellulase complex and by the individual endoglucanase (pI 4.4–5.2) and cellobiohydrolase (pI 4.0–4.2) has been studied. A flow chart for the enzymatic hydrolysis of the cellulose has been revealed, which formed a basis for a computer simulation of the kinetic regularities observed. As a result of it, the values of the catalytic rate constants for the individual stages of the enzymatic degradation of MC have been calculated. Then, the synergistic behaviour of endoglucanase and cellobiohydrolase in the hydrolysis of MC has been described both quantitatively and graphically. The relative efficiency of the individual stages for the MC hydrolysis in terms of glucose and cellobiose formation for cellulase complexes of various composition has been calculated. It was quantitatively shown that cellobiohydrolase plays the key role in the MC hydrolysis by T. reesei cellulase preparations, because it gives up to 80% glucose and up to 80–90% cellobiose in the presnce of endoglucanase which in turn plays a relatively minor role in a direct formation of both soluble products of the hydrolysis.
Verfahren und Analysenautomat zur Bestimmung von Nährlösungskomponenten und Stoffwechselprodukten
Authors: Weise H. , Kreibich G. , Scheller F.
Published: December 2004

A continuous flow system with an enzyme electrode and with a new type of measuring instrument, the BIOXY‐Meter, is described as an example for the determination of glucose. The BIOXY‐Meter combined with various biosensors may be used in biotechnology and in other fields for the solution of a number of analytical problems. Measuring principle is the reduction of oxygen. The peak of first derivation of the current‐time‐curve is proportional to oxygen consumption and to decrease of substrate concentration. Enzyme fixation with common adhesive and a device for automated saturation of measuring samples with air in the sampler are also described. With the apparatus 60 samples per hour are analyzed for glucose. The linear measuring range is 0.1 mMol to 1.5 mMol with a coefficient of variation of Vk = 0.93 per cent. The described type of enzyme electrode is stable for 2 to 12 weeks or 1,000 to 5,000 measurements.
Ethanol concentration determination using solvent extraction and refractometry
Authors: Lazarova G. , Genova L. , Kostov V.
Published: December 2004

The feasibility to avoid the distillation in the case of refractometric determination of the ethanol concentration in fermentation samples is examined. The results obtained show that the ethanol concentration in the range 0 to 100 g.1−1 can be easily determined by means of benzyl alcohol extraction and refractometry.
Effects of temperature on microbial ethanol production. II. A thermodynamic interpretation of the temperature profile curve of ethanol production
Authors: Richter K.
Published: December 2004

An attempt is made to give a thermodynamic interpretation of the complete temperature profile curve of ethanol formation. Taking into consideration an enhancing competition between thermal activation and thermal deactivation of ethanol formation at increasing temperatures and supposing that the ethanol production is affected by a reversible and an irreversible term of thermal deactivation of a modified ARRHENIUS equation being current for the total biokinetic sphere may be derived:

.

The quantities ΔH and ΔHD2T are identical with the temperature functions of the change of entropy caused by reversible and irreversible deactivation of ethanol formation, respectively. Accordingly for the yeast strain Saccharomyces cerevisiae Sc 5 the calculated entropy coefficients of reversible and irreversible thermal deactivation of ethanol formation amount to C = (0.245± 0.013) kJ/mol · deg.2 and C = (1.657 ± 0.046) kJ/mol · deg.2.
Submerged fermentation of cellolignin materials (compared with solid‐state fermentation and other alternatives)
Authors: Zeltina M. O. , Leite M. P. , Vanags J. J. , Apine A. J. , Viesturs U. E.
Published: December 2004

The review characterizes the submerged and solid state fermentation processes (SF and SSF) for obtaining of microbial biomass protein (MBP) on cellulose‐ and lignin‐containing (CL) agricultural wastes (straw, wine, branches of fruit trees). There are discussed other alternatives as well. The main technological parametres are presented (protein (biomass) yield, degree of available substrate utilization, process efficiency, etc.). The use of a special stirring system of the authors' design for mycelial cultures results in an increase of CL substrate concentration in the initial nutrient medium from 2% to 8%of dry matter (DM) and in a threefold increase of the specific productivity (from 0.07 g biomass/l · h to 0.21 g biomass/l · h). The technological parametres can be increased also in the processes with substrate addition. The obtained preparations are analyzed as to their usefulness for the feeds of ruminants.
D‐amino acid oxidase, aromatic L‐amino aminotransferase, and aromatic lactate dehydrogenase from several yeast species: Comparison of enzyme activities and enzyme specificities
Authors: Bode R. , Birnbaum D.
Published: December 2004

Production of D‐amino acid oxidase, L‐aromatic aminotransferase and aromatic lactate dehydrogenase by several yeast species was examined. Of 16 strains tested, Trigonopsis variabilis and Rhodosporidium toruloides were found to be most suitable for D‐amino acid oxidase production, T. variabilis and Brettanomyces anomalus for L‐aromatic aminotransferase production, and Hansenula polymorpha, Cryptococcus terreus, and Candida maltosa for aromatic lactate dehydrogenase production. This selection is based on a high amount of enzyme activity as well as a broad enzyme specificity. The data will be reported here.