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21.
22.
G. -J. A. Vidugiris A. V. Gudavičius V. J. Razumas J. J. Kulys 《European biophysics journal : EBJ》1989,17(1):19-23
Surface enhanced Raman scattering (SERS) of some enzymes (alkaline phosphatase, horseradish peroxidase and lactoperoxidase) and some amino acids (tryptophan, tyrosine and phenylalanine) on silver electrodes has been studied. The spectral band intensities of certain amino acids and amino acid residues were determined by their orientation on the surface and depended on the electrode potential (E).Abbreviations SERS
surface enhanced Raman scattering
- Trp
tryptophan
- Tyr
tyrosine
- Phe
phenylalanine
- E
electrode potential
- ORC
oxidation-reduction cycle 相似文献
23.
Aleš Vančura Ivana Vančurová Jan Kopecký Jaroslav Maršálek Daniel Cikánek Gabriela Basařová Vladimir Křišťan 《Archives of microbiology》1989,151(6):537-540
Synthesis of threonine dehydratase in Streptomyces fradiae was positively influenced by valine and negatively by isoleucine. However, these two amino acids had no effect on the activity of this enzyme. Synthesis of threonine dehydratase in -aminobutyrate resistant mutants of S. fradiae was pronouncedly less sensitive to the positive effect of valine and this change in regulation led to valine overproduction. Synthesis of acetohydroxy acid synthase is regulated in a similar manner to that of threonine dehydratase, however a lower level of expression was detected in -aminobutyrate resistant mutants. And again, no effect of branched-chain amino acids on acetohydroxy acid synthase activity was observed. It follows that in S. fradiae synthesis of threonine dehydratase is the main regulatory mechanism governing production and the mutual ratio of synthesized valine and isoleucine.Abbreviations -AB
-aminobutyrate
- AHAS
acetohydroxy acid synthase
- -KB
-ketobutyrate
- MNNG
N-methyl-N-nitro-N-nitrosoguanidine
- TD
threonine dehydratase
- Trans. B.
transaminase of branched-chain amino acids
- VDH
valine dehydrogenase 相似文献
24.
Synopsis Evidence is presented which suggests that the nonparasitic lamprey, Lampetra (Eudontomyzon) gracilis Kux, 1965, is conspecific with the parasitic lamprey Eudontomyzon danfordi Regan, 1911. The diagnostic characters of the holotype and of the non-type material of E. gracilis are features found in E. danfordi specimens in their second and final year of adult life, thereby making the former a junior synonym of the latter. 相似文献
25.
Summary Immobilization of Escherichia alcalescens cells into genu-carrageenan gel for L-aspartic acid production was studied with respect to the optimized preparation of heterogenous biocatalyst /2.5–3.0% genu-carrageenan, 15% biomass, 50–55 °C, tannin added/. 相似文献
26.
Elizabeta Pertot Damjana Rozman Stjepan Miličić Helena Sočič 《Applied microbiology and biotechnology》1988,28(2):209-213
Summary The morphological development ofClaviceps paspali immobilized in Ca-alginate gel was examined. During consecutive reincubations, the immobilized mycelia differentiated into swollen, arthrosporoid-like cells, which never appeared during fermentation of free mycelium. Such differentiation could be connected with the improved, prologed vitality and metabolic activity of the immobilized cells. 相似文献
27.
Miroslav Flieger Jaroslav Votruba Vladimír Křen Sylvie Pažoutová Viktor Rylko Přemysl Sajdl Zdeněk Reháček 《Applied microbiology and biotechnology》1988,29(2-3):181-185
Summary Kinetic parameters of production of clavine alkaloids were evaluated in twoClaviceps purpurea strains. Mutagenesis brought about enhanced resistance of the biosynthetic system towards alkaloids. Addition of glucose into the fermentation medium altered the zero order kinetics of production to activation-inhibition kinetics. The glucose treatment allowed performance of both elymoclavine-inhibitionless and clavine alkaloid-decompositionless fermentations if a combination of fermentation and separation units in a closed loop was used.Nomenlacture
k
1
rate constant of agroclavine synthesis (mg Agro · mg Elymo/l·g DW·day for stage 1, mg Agro/g DW·day for stage 2)
-
k
2
parameter describing inhibition of agroclavine formation rate by elymoclavine (mg Elymo/l)
-
k
3
specific rate of agroclavine decay (l/g DW·day)
-
k
4
maximal specific rate of elymoclavine synthesis (stage 1, 1/g DW·day, stage 2, mg Elymo/g DW·day)
-
k
4
–
maximal specific rate of elymoclavine synthesis in stage 1 (inhibition-activation mechanism) (mg Elymo/g DW·day)
-
k
5
physiological constant describing the elymoclavine decay rate (l2/g DW·day·mg Elymo)
-
k
5
–
physiological constant describing the activation of elymoclavine biosynthesis by elymoclavine (mg Elymo/l)
-
k
6
physiological constant describing the repression of elymoclavine biosynthesis by elymoclavine (mg Elymo/l)
-
k
7
maximal specific growth rate (1/day)
-
k
8
specific rate of biomass decay (l/g DW·day)
-
A
agroclavine concentration (mg/l)
-
E
elymoclavine concentration (mg/l)
-
r
A
specific rate of agroclavine biosynthesis (mg Agro/g DW·day)
-
r
E
specific rate of elymoclavine biosynthesis (mg Elymo/g DW·day)
-
r
i
specific rate of alkaloid biosynthesis (mg alkaloid/g DW·day)
-
X
dry biomass concentration (g/l)
-
specific growth rate (1/day)
Abbreviations Agro
agroclavine
- Elymo
elymoclavine
- Chano
chanoclavine
- DW
dry weight of biomass 相似文献
28.
J. Šťovíčková J. Turková B. Urbánek V. Bažant J. Kavalírová 《Biotechnology Techniques》1988,2(2):121-126
Summary The effect was studied of the method of drying chymotrypsin attached to bead cellulose on its chemical and physical characteristics. These characteristics are not deteriorated when replacing the commonly used lyophilisation by fluid drying in the air stream. The preparations saved essentially the same proteolytic activity as well as stability even when increasing the drying air temperature to 70°C. 相似文献
29.
In order to improve the interpretation of the results of pollen analyses concerning mediaeval anthropogenous sediments a set of recent seeds of the principal cereals was pollenanalytically elaborated. The aim was to find out whether pollen grains can be preserved on mature seeds. The pollen spectra obtained from the material of mediaeval anthropogenous sediments include, in most cases, a large amount of pollen of certain plants including cereals. It is suggested that part of the pollen spectra from anthropogenous sediments need not come from air transport, i.e. from the surrounding vegetation; it could get into waste pits in another way. Above all, some foodstuffs were considered to be the sources of pollen grains. The origin of some grains coming from honey and from plant infusions has, at least partly, been demonstrated (Jankovská 1987). As the next step, attention was paid to other products, mainly those of cereals. An experimental pollen analysis of recent seeds of selected cereals showed that pollen grains are preserved on their surface, often in high concentrations. This is due, above all, to the cleistogamy of most cereals. The highest values of pollen grains have so far been found inAvena sativa andPanicum milliaceum. Triticum aestivum andHordeum vulgare showed lower values of pollen grains. The lowest amounts were found in heterogamousSecale cereale. Simultaneously, the pollen of plants growing in a neighbourhood, above all the pollen of field weeds, was found sticking to the seeds. 相似文献
30.
Zbyněk Roček 《Pal?ontologische Zeitschrift》1991,65(3-4):351-361
Three-dimensionally preserved and chemically prepared skulls and natural casts of representatives of the families Benthosuchidae, Melosauridae, and Capitosauridae yield data on the structure of the ethmoidal endocranium, i. e. of those nasal cranial structures that consisted originally of cartilage. This study demonstrates that the ethmoidal endocranium was principally a dorsoventrally compressed plate, pierced by a broad and oblique canal which communicated anteriorly with the outer dorsal surface by the fenestra endonarina and posteriorly with the mouth cavity by the fenestra endochoanalis(seu foris). The canal was very short, and housed the olfactory organ. The ethmoidal endocranium was connected with the palatoquadrate by the commissura quadratocranialis anterior; there was no lateral ethmoidal commissure, however, in older individuals the anterior section of the palatoquadrate might also contact the postchoanal part of the nasal endocranial skeleton. 相似文献