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51.
Merten OW 《Cytotechnology》1988,1(2):113-121
Batch cultures of mouse-mouse hybridoma cell lines were carried out and their growth and production kinetics investigated. Three main cell specific production patterns (expressed as pg IgG/cell x hour) were found, which can be used as a classification system for hybridoma cell lines (groups I–III). Cells showing the highest IgG-production at the beginning of the batch culture (during the lag and the onset of the log-phase) were classified as either group I and II. The difference was that cell lines of group II showed a second high cell specific production at the onset of the stationary and death phases. Cell lines of group III had a quite constant production of antibodies during their growth; but IgG secretion completely stopped after the beginning of the stationary phase. The implications of these three production patterns on the design of a production process are discussed. 相似文献
52.
Mycelium ofBeauveria bassiana can be grown in liquid culture, filtered, and the mycelium dried. After rehydration the mycelium sporulates.
Two carbohydrate sources (sucrose and maltose), and one nitrogen/vitamin source (yeast extract) were tested for mycelium growth
and subsequent conidial production. Maximum mycelium growth (12.31 mg/ml), in liquid culture, was in the sucrose (3.5%)/yeast
extract (3.5%) medium, but mycelium from a maltose (2%)/yeast extract (0.75%) medium produced the maximum of 4.62×106 conidia/mg dry mycelium after incubation in moist Petri dishes.
Using the data on mycelium yield (in liquid culture) and conidial production (by dry mycelium) it is calculated that the sucrose
(3.5%)/yeast extract (3.5%) and the maltose (2%)/yeast extract (0.75%) media produce most conidia per media volume (an equivalent
of 3.52–3.72×107 conidia/ml).
相似文献
53.
The correlation between manganese deficiency, loss of mitochondrial respiratory chain NADH: ubiquinone oxidoreductase (complex I) activity and citric acid overproduction in the Aspergillus niger strain B 60 was analysed. With increasing manganese-supplementation of the production medium the loss of complex I activity and the production of citric acid was reduced. Addition of manganese during growth stopped further loss of complex I activity and further increase of citric acid production. A possible causality between complex I deficiency and citric acid overproduction is discussed. 相似文献
54.
Marie A. Salmeron Tatsuo Morita Hidetoshi Seki Chris D. Platsoucas Kyogo Itoh 《Cancer immunology, immunotherapy : CII》1992,35(3):211-217
Summary Lymphokine production by human melanoma tumor-infiltrating lymphocytes (TIL) was studied. Uncultured TIL produced interferon (IFN), but not interleukin-2 (IL-2) or IL-4, in response to anti-CD3 mAb or IL-2. In bulk cultures, IL-2-activated TIL displaying autologous tumor-specific cytotoxicity (CTL-TIL) produced IFN in culture with medium alone, whereas IL-2-activated noncytotoxic TIL did not. Addition of anti-CD3 mAb or autologous tumor cells up-regulated IFN production in IL-2-activated TIL from 10 of 12 or 6 of 12 cases respectively. Those from 4 of 12 cases (2 CTL-TIL and 2 noncytotoxic TIL) produced IL-2 in culture with medium alone. At the clonal level, 5 (4 CD4+ and 1 CD8+) of 7 autologous tumor-specific CTL clones derived from TIL and 3 (2 CD4+ and 1 CD8+) of 7 noncytotoxic TIL clones produced IFN in culture with medium alone, which was up-regulated by adding anti-CD3 mAb. Two IFN-producing CTL clones tested produced IL-2 in 4 ×-concentrated supernatants from a 3.5-h culture with medium alone. Furthermore, 2 IFN-producing CTL clones tested expressed mRNA for both IFN and IL-2. IL-2 production and its mRNA expression were up- or down-regulated, respectively, by adding anti-CD3 mAb or autologous tumor cells. IL-4 production was not observed in culture either with medium alone or with IL-2 in any of the cells described above. Anti-CD3 mAb was required for IL-4 production in 3 of 12 IL-2-activated TIL, 2 of 6 CTL clones, and none of 5 noncytotoxic TIL clones. In summary, IFN production was characteristic of melanoma TIL. Some autologous tumor-specific CTL in TIL are suggested to be productive of IL-2 and IFN under unstimulated conditions, both being required for self-activation in an autocrine loop.This work was supported in part by grant CA-47891 from the National Cancer Institute 相似文献
55.
Metabolism of nitric oxide and nitrous oxide during nitrification and denitrification in soil at different incubation conditions 总被引:1,自引:0,他引:1
Abstract NO production and consumption rates as well as N2 O accumulation rates were measured in a loamy cambisol which was incubated under different conditions (i.e. soil moisture content, addition of nitrogen fertilizer and/or glucose, aerobic or anaerobic gas phase). Inhibition of nitrification with acetylene allowed us to distinguish between nitrification and denitrification as sources of NO and N2 O. Under aerobic conditions untreated soil showed very low release of NO and N2 O but high consumption of NO. Fertilization with NH4 + or urea stimulated both NO and N2 O production by nitrification. Addition of glucose at high soil moisture contents led to increased N2 and N2 O production by denitrification, but not to increased NO production rates. Anaerobic conditions, however, stimulated both NO and N2 O production by denitrification. The production of NO and N2 O was further stimulated at low moisture contents and after addition of glucose or NO3 − . Anaerobic consumption of NO by denitrification followed Michaelis-Menten kinetics and was stimulated by addition of glucose and NO3 − . Aerobic consumption of NO followed first-order kinetics up to mixing ratios of at least 14 ppmv NO, was inhibited by autoclaving but not by acetylene, and decreased with increasing soil moisture content. The high NO-consumption activity and the effects of soil moisture on the apparent rates of anaerobic and aerobic production and consumption of NO suggest that diffusional constraints have an important influence on the release of NO, and may be a reason for the different behaviour of NO release vs N2 O release. 相似文献
56.
Summary High yields of protoplasts were obtained from leaves of aseptically grown plants and calli originated from different explants, in several cultivars of Cajanus cajan L. The protoplasts divided to form cell clusters in modified KM 8p medium and developed to protocolonies after dilution with liquid Caboche's medium within three to four weeks of culture. The protocolonies proliferated to form green calli on solid Caboche's medium. No shoots or plants were obtained.Abbreviations BAP
6-benzylaminopurine
- NAA
-napthaleneacetic acid
- 2,4-D
2,4-dichlorophenoxyacetic acid
- Kin
kinetin
- Zea
zeatin
- Adn S
adenine sulphate
- GA 3
gibberellic acid 相似文献
57.
Kenji Kato Su-wan Oh Hiroyuki Yamamoto Takayuki Hanazato Ikuko Yasuda Akira Otuki Masayuki Takahashi 《Ecological Research》1992,7(3):267-276
In order to understand the control mechanisms of a large, stable bacterial standing stock, enclosure experiments were conducted
in a eutrophic lake, where both bacterial productivity and grazing pressure were very high. Total bacterial number in the
different enclosures ranged from 1.2 to 2.7×107 cells mL−1 throughout the experiment. The average bacterial cell production rate estimated from a grazer eliminating experiment was
6.3×105 cells mL−1 h−1. Difference in the bacterial cell production rate between shaded and unshaded enclosures was not apparent. Bacteria showed
a reduction in standing stock of only about 25–30% even after the supply of light was cut to 1%. Bacteria in the shaded enclosures
then recovered their production rate in the first 12 days of perturbation. Grazing pressure in the shaded enclosures was not
less than that for the control. Thus, it was considered a control mechanism of bacterial stable standing stock that the bacteria
shifted their organic substrate from extracellular dissolved organic carbon freshly released from phytoplankton to that already
stocked in the water column, though it is not known whether the dominant bacteria were the same. 相似文献
58.
Anthraquinones produced by suspension cultures of Galium vernum are completely retained intracellularly. Surprisingly, in the presence of some polymeric adsorbents anthraquinones are partially released into the culture medium. The secretion and in situ removal stimulates anthraquinone production in cell cultures of Galium vernum. Best results were obtained with Wofatit ES and Amberlite XAD-2.Abbreviations DW
dry weight
- MS
Murashige & Skoog[7]medium
- NAA
1-naphthaleneacetic acid 相似文献
59.
Studies on blastospore production in different liquid media were conducted with three strains of Metarhizium anisopliae var. anisopliae (M. a.) derived from various countries (M. a. 43: Austria, M. a. 57: Brazil, M. a. 97: Philippines). Variation of six fermentation parameters (cornsteep products, carbohydrates, pH values, temperature, Tween 80, and polyethyleneglycol (PEG) 200) disclosed that the three strains of M. anisopliae differed in their growth pattern and physiology. In standard medium and in all tests, M. a. 57 produced the highest number of blastospores invariably amounting to > 108 per ml, while mycelial pellets were never formed. The preferred carbohydrates were glucose and fructose. Blastospore production of M. a. 43 was increased by growth at 30°C, at pH 6.5 or by addition of 5% PEG 200. However, it was impaired by different concentrations of Tween 80 or higher concentrations of PEG 200 (10–15%). M. a. 97 produced most blastospores at 30°C, and the strain preferred basic (pH 8.0) as well as acid (pH 4.5) media. Blastospore production was increased by the addition of 5% PEG 200 or 0.4–1.2% Tween 80. Moreover, PEG 200 suppressed pellet formation effectively. Altogether, our results showed that for optimal blastospore production of Metarhizium anisopliae, suitable strain‐specific parameters have to be evaluated. 相似文献
60.
P. N. Nehete N. K. Shah V. Ramamurthy R. M. Kothari 《World journal of microbiology & biotechnology》1992,8(4):446-450
An economical protocol, which is simple, rapid and reproducible for the production of maltose by enzymatic hydrolysis of tapioca starch, has been optimized. The protocol involves liquefaction of 35% (w/w) tapioca starch by bacterial -amylase at 78±2°C to 3 to 5% (w/w) reducing sugars, followed by maximal (85±3% w/w maltose equivalent) saccharification with barley -amylase and pullulanase at 50°C for 24 to 30 h. The post-saccharification recovery protocol comprised decolourization by charcoal, de-dextrinization by denatured spirit precipitation, de-ionization by passage through cation and anion exchangers and dehydration by vacuum drying. A white crystalline maltose powder was obtained with specifications comparable to commercial high purity maltose. The protocol yields at least 60% (w/w) recovery of maltose and is suitable for use by the pharmaceutical industry. The protocol is unique in that it utilizes cheap and easily hydrolysed tapioca starch, leaves no mother liquor, enabling higher recovery of maltose, and allows almost quantitative recovery of limit maltodextrins, a value-added marketable by-product. 相似文献