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Max Häggblom Juha Apajalahti Mirja Salkinoja-Salonen 《Applied microbiology and biotechnology》1986,24(5):397-404
Summary A polychlorophenol degrader, Rhodococcus chlorophenolicus, was shown to metabolize five different chlorinated guaiacols, namely tetrachloroguaiacol, 3,4,6-trichloroguaiacol, 3,5,6-trichloroguaiacol, 3,5-dichloroguaiacol and 3,6-dichloroguaiacol. Seven different intermediate metabolites, each with three hydroxyl or methoxyl groups, were identified. Four of these metabolites were also dehalogenation products, three carrying one chlorine atom less than the parent compound, and one metabolite from tetrachloroguaiacol where two chlorine atoms had been removed. Tetrachloroguaiacol was shown to undergo reductive dehalogenation. Demethylation of guaiacol to catechol was observed with the dichloroguaiacols, but not with polychloroguaiacols.Abbreviations DCG
dichloroguaiacol
- TCG
trichloroguaiacol
- TeCG
tetrachloroguaiacol
- DCC
dichlorocatechol
- TCC
trichlorocatechol
- TeCC
tetrachlorocatechol
- TCP
trichlorophenol
- TeCP
tetrachlorophenol
- PCP
pentachlorophenol. An example of numeration
- 346-TCG
3,4,6-trichloroguaiacol
- GLC
gas liquid chromatography 相似文献
24.
Max Kaufmann Jorgen Marqverson Kenneth E. Stanley Christian Mouritzen Hans Hvid-Hansen 《Cancer immunology, immunotherapy : CII》1986,22(1):56-61
Summary The distribution of Corynebacterium parvum labeled with 131iodine or 99mtechnetium was studied in 17 patients with bronchogenic carcinoma. The labeled bacteria were given intravenously or intrapleurally and monitored by whole-body gamma tracking and samples of blood and urine. Even though the rate of physical decay is quite different for 131iodine and 99mtechnetium, the tracking time of labeled bacteria was limited to 24 h after injection for both radioactive isotopes. Technetium labeling was preferred because of greater imaging resolution and less radiation dose to the patient. Following intravenous administration, labeled C. parvum was found predominantly in the liver and spleen, and in a lesser amount in the lung. Radioactivity was confined to the pleural cavity after intrapleural injection. These results suggest the combined intravenous and intrapleural route of adjuvant immunosupportive agents such as C. parvum for operable lung cancer patients. 相似文献
25.
Light-temperature interactions in the control of photosynthesis in Antarctic phytoplankton 总被引:6,自引:4,他引:2
Summary During October/November 1983 photosynthetic responses of natural phytoplankton from the Scotia Sea and Bransfield strait to light and temperature were examined in incubators. Both assimilation numbers at saturating light levels and the slopes of the light-limited portions of the photosynthesis versus irradiance curves were smaller than in algae from lower latitudes. However, both parameters increased significantly with rising temperatures. Light-saturated photosynthesis on the average exhibited a Q10-value of ca. 4.2 between-1.5°C and +2°C. Light-limited photosynthesis between-1.5°C and +5°C rose at a rate corresponding to a Q10-value of roughly 2.6. Above +5°C, temperature enhancement of both light-saturated and light-limited photosynthetic rates was minimal or absent. Our results suggest that under extremely low temperatures light-limited photosynthetic rates become temperature-dependent due to changes in maximum quantum yields. 相似文献
26.
Macrophages express cell surface laminin 总被引:4,自引:0,他引:4
Laminin, a non-collagenous extracellular connective tissue glycoprotein, was detected on the surface of mouse peritoneal macrophages. As determined by indirect immunofluorescence, as many as 60% of peritoneal macrophages elicited with thioglycollate expressed cell surface laminin. Only 14% of resident cells displayed detectable laminin. The expression of laminin increased with time post-injection. Concomitant with laminin expression, macrophages also displayed a receptor for the IB4 isolectin from Griffonia simplicifolia. This lectin, which binds methyl-alpha-D-galactopyranoside, may also react with the carbohydrate moeity of laminin. A small population of macrophages displayed both laminin and surface fibronectin. Unlike the difference in laminin expression between resident and thioglycollate-stimulated cells, there was no difference in cell surface fibronectin between these cell populations. Since laminin has been found to mediate cell attachment in other systems, expression of this molecule on the surface of stimulated macrophages may be important in cell-cell and cell-matrix adhesive properties of these cells. 相似文献
27.
Application of Response Surface Methodology to Evaluation of Bioconversion Experimental Conditions 总被引:3,自引:0,他引:3 下载免费PDF全文
Vronique Cheynier Max Feinberg Constantin Chararas Christian Ducauze 《Applied microbiology》1983,45(2):634-639
Using Candida tenuis, a yeast isolated from the digestive tube of the larva of Phoracantha semipunctata (Cerambycidae, Coleoptera), we were able to demonstrate the bioconversion of citronellal to citronellol. Response surface methodology was used to achieve the optimization of the experimental conditions for that bioconversion process. To study the proposed second-order polynomial model, we used a central composite experimental design with multiple linear regression to estimate the model coefficients of the five selected factors believed to influence the bioconversion process. Only four were demonstrated to be predominant: the incubation pH, temperature, time, and the amount of substrate. The best reduction yields (close to 90%) were obtained with alkaline pH conditions (pH 7.5), a low temperature (25°C), a small amount of substrate (15 μl), and short incubation time (16 h). This methodology was very efficient: only 36 experiments were necessary to assess these conditions, and model adequacy was very satisfactory as the coefficient of determination was 0.9411. 相似文献
28.
A review has been compiled illustrating the directions taken in examining the genotoxic effects of metals and their compounds centering only on those studies pertaining to effects of metals and their compounds on DNA structure and function, such as the induction of DNA strand breaks, production of DNA-protein crosslinks, induction of chromosomal aberrations, and sister chromatid exchanges. Although it is premature to declare a cause and effect relationship between the carcinogenic activity of metals and their ability to induce one or more lesions in DNA, strong evidence is emerging to suggest such a relationship. Low concentrations of metals induce the appearance of DNA lesions, such as strand breaks and crosslinks, or induce sister chromatid exchanges or DNA repair synthesis. Assays based upon these events constitute extremely sensitive probes for genotoxic effects of metals and their compounds. These effects of metals on DNA are consistent with the currently accepted mechanism of chemical carcinogenesis, allowing the acquisition and propagation of altered DNA function. The lack of complete information on the activity of metals in producing DNA lesions allow only preliminary conclusions to be drawn. Certain compounds containing potentially or actually carcinogenic elements, such as Ni, Be, As, Cr, Cd, and to a minor extent Pb, have yielded positive responses in one or more DNA lesion assays. At relatively nontoxic levels of Ni and Cr, considerable evidence suggests that multiple types of DNA lesions are induced. 相似文献
29.
Nucleotide pools of growing,synchronized and stressed cultures of Saccharomyces cerevisiae 总被引:6,自引:0,他引:6
Günther Ditzelmüller Wilfried Wöhrer Christian P. Kubicek Max Röhr 《Archives of microbiology》1983,135(1):63-67
High pressure liquid chromatography has been used to study the acid soluble nucleotide pool of Saccharomyces cerevisiae under different conditions of growth. ATP, ADP, AMP, NAD, GTP, UTP, UDP, CTP, CDP, and UDP-sugars plus UMP could be separated and were found in concentrations higher than 0.1 mumol per g yeast cell dry weight (= detection limit). During glucose-limited continuous culture the levels of individual nucleotides depended on the growth rate, which was most pronounced with pyrimidine (uridine, cytidine) nucleotides. The energy charge (E.C.) remained high (0.9) at all growth rates (0.07-0.3 h-1). During synchronized growth at a constant growth rate (0.11 h-1) almost all nucleotide levels and the E.C. remained at constant values with the only exception of UDP-sugars and UMP of which increased levels were found during the phase of budding. Under conditions of metabolic stress (addition of antimycin A, deoxyglucose plus iodoacetate) pronounced changes in the levels of purine (adenine and guanine) nucleotides and the E.C. were observed. All other nucleotides were less influenced by these conditions. Only under these conditions IMP accumulation was observed. The results strongly argue against the significance of purine nucleotide or E.C. measurements under viable conditions. In contrast, changes in the levels of pyrimidine nucleotides seem to be indicative of changes in the flux through the metabolic pathways where they act as coenzymes. 相似文献
30.
Association of Alleles of the Malic Dehydrogenase Locus with a Pericentric Inversion in DROSOPHILA ROBUSTA 下载免费PDF全文
Associations of Malic dehydrogenase alleles with the third chromosome arrangement 3R and the pericentric arrangement 3L-R are described. Even though significant associations between alleles and inversions exist within a population, there is an overall similarity in MDH allele frequencies in different populations inspite of large differences in inversion frequencies. 相似文献