两种发菜培养体系的筛选

采用两种培养液,其中加入不同激素,并设置一定的浓度梯度,观察其对发菜生长及含氮量的影响。初步结果表明;培养液2中的发菜生长情况优于培养液1中的,不仅发菜增长率高,解体程度也低;两种培养液中的均是加入5mg/L NAA的发菜生长最好,培养液2的平均增长度达19.8%,培养液1的达10.7%;培养液2中的发菜的含氮量高于培养液1中的,但含氮量与激素种类和浓度无相关性。     

Liposomes replace serum for cultivation of fermenting mycoplasmas

Cholesterol and albumin are limiting factors in the growth of Mycoplasma species. These nutrients are usually supplied in the culture medium by the addition of serum. The growth of M. pneumoniae in a serum-free medium containing an ethanolic cholesterol suspension and albumin was about one-half the level attained in serum-containing medium. M. gallisepticum and M. fermentans were not cultivable in the cholesterol suspension medium even after supplements were included. In another culture medium containing phosphatidylcholine-cholesterol liposomes and albumin as serum replacements, the growth of M. pneumoniae was approximately equal to that in serum-containing medium, and the growth of M. gallisepticum and M. fermentans was significantly greater than that in medium containing serum. M. fermentans produced even higher yields in liposome medium supplemented with arginine. These fermenting mycoplasmas readily adapted to the liposome medium and by the fifth or sixth serial passage produced thick confluent growth on the lower surface of culture bottles. To obtain maximum growth, we serially transferred the mycoplasmas at least 10 times in serum-free medium before quantitations of growth were made. This is the first report of a serum-free mycoplasma medium of high growth-promoting ability.     

Liposomes replace serum for cultivation of fermenting mycoplasmas.

Cholesterol and albumin are limiting factors in the growth of Mycoplasma species. These nutrients are usually supplied in the culture medium by the addition of serum. The growth of M. pneumoniae in a serum-free medium containing an ethanolic cholesterol suspension and albumin was about one-half the level attained in serum-containing medium. M. gallisepticum and M. fermentans were not cultivable in the cholesterol suspension medium even after supplements were included. In another culture medium containing phosphatidylcholine-cholesterol liposomes and albumin as serum replacements, the growth of M. pneumoniae was approximately equal to that in serum-containing medium, and the growth of M. gallisepticum and M. fermentans was significantly greater than that in medium containing serum. M. fermentans produced even higher yields in liposome medium supplemented with arginine. These fermenting mycoplasmas readily adapted to the liposome medium and by the fifth or sixth serial passage produced thick confluent growth on the lower surface of culture bottles. To obtain maximum growth, we serially transferred the mycoplasmas at least 10 times in serum-free medium before quantitations of growth were made. This is the first report of a serum-free mycoplasma medium of high growth-promoting ability.     

Growth limitation of 3T3 mouse fibroblasts by available growth surface area and medium components

Studies with untransformed fibroblasts demonstrate that growth of these cells in culture can be limited by the availability of both growth surface and medium components. Experiments using cells grown on coverslips, in which the only variable was available growth surface, indicate that when the medium to cell ratio is high, surface area is the principal factor limiting growth. At low medium to cell ratios, however, growth of cells is predominantly limited by medium components. The final number of cells per culture is almost directly proportional to available surface area when the culture medium is changed daily.     

Roles of various growth factors in growth of human osteosarcoma cells which can grow in protein-free medium.

The human osteosarcoma cell line (OST-1-PF) can grow in protein-free Coon's modified Ham's F12 medium. Growth of the cells in protein-free medium was partially density-dependent and partially depressed by medium change. An extract and conditioned medium of OST-1-PF cells contained high mitogenic activity for BALB/c3T3 cells. The growth factor in the cells was purified and identified as a basic fibroblast growth factor (bFGF)--like factor on the basis of its elution profile on heparin-affinity chromatography and the result of immunoblotting. An unidentified factor in a conditioned medium eliciting most of the DNA synthesis-stimulating activity showed a weak affinity for heparin. Various additions, including serum and growth factors, stimulated the growth of OST-1-PF cells in protein-free medium. Of these factors, epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha), acidic fibroblast growth factor (aFGF) and bFGF were the most potent mitogens. High-affinity receptors of EGF and FGF were found on the surface of these cells. These results indicate that autonomous growth of OST-1-PF cells in protein-free medium is mainly controlled by an intracellular mechanism.     

壳寡糖对乳酸杆菌体外生长的影响

目的:研究壳寡糖对乳酸杆菌体外生长的影响。方法:将乳酸杆菌MRS培养基中的葡萄糖替换为壳寡糖及向原培养基中加入适量的壳寡糖,通过测定OD值比较乳酸杆菌的生长状况。结果:以壳寡糖完全代替葡萄糖的培养基中乳酸杆菌的生长状况不如MRS培养基,而少量壳寡糖与葡萄糖协同的培养条件使乳酸杆菌的生长适应期明显减短,促进其生长。结论:乳酸杆菌对壳寡糖的利用不如对葡萄糖的利用,1g/l壳寡糖与葡萄糖协同作用时可明显缩短乳酸杆菌的生长适应期,促进细菌生长。     

Growth studies on xenic cultures of Entamoeba gingivalis using established media

Wantland's egg medium, modified Shaffer-Frye (MSF) medium and Tryptose-Trypticase-Yeast Extract-Serum-Blood (TTY-SB) medium were compared with variations of the latter two media for their ability to support xenic growth of Entamoeba gingivalis. Wantland's egg medium was unsuitable for growth of E. gingivalis. Accompanying bacteria became resistant to penicillin and streptomycin, overwhelming the amoeba culture. MSF medium was also unsuitable for the cultivation of E. gingivalis. Bacterial growth was heavy and protozoan growth sparse. MSF medium without mercaptosuccinic acid, but with rice starch, dextran or levan substituted for glucose and with Yersinia enterocolitica added, supported limited growth of the amoeba. Unmodified TTY-SB medium did not sustain growth of E. gingivalis. However, when rice starch suspension was substituted for glucose, -cysteine HCl was deleted, and a Crithidia sp. was added to the E. gingivalis culture grown xenically, enhanced growth of the oral amoeba resulted in this modified TTY-SB medium. E. gingivalis is very sensitive to changes in incubation temperature. Optimum growth was found to be in the narrow range from 34.5 to 35°C for all media tested.     

Growth and development kinetics of Bacillus thuringiensis in batch culture

The kinetics of Bacillus thuringiensis growth and its assimilation of nutrient substances were studied under the conditions of batch cultivation in a complex medium containing yeast extract and in a chemically defined medium with amino acids. The growth of B. thuringiensis can be divided into five phases: exponential growth; decelerated growth; stationary phase when protein crystals are formed; stationary phase when spores are formed; lysis of sporangia releasing spores. The first phase may in turn be subdivided into three stages according to changes in the specific growth rate and substrate assimilation: a high specific growth rate and no glucose assimilation; an abrupt drop in mu and the beginning of intensive glucose assimilation from the medium; a new rise in the specific growth rate. As follows from the results of studying the kinetics of B. thuringiensis growth in a chemically defined medium, the above changes in the exponential growth phase are due to the fact that the culture assimilates yeast extract components in the complex medium or amino acids in the chemically defined medium during this phase, and then starts to assimilate glucose and ammonium in the following phases of growth.     

Identification of lactoferrin as an essential growth factor for human lymphocytic cell lines in serum-free medium

A serum-free medium supplemented with growth factor(s) was devised to grow human lymphocytic cell lines. The medium was developed using human lymphocytic cell line, Bri 7 cells. In the process of constructing the medium, human lactoferrin was found to be an essential growth factor for the cell line. Human lactoferrin has higher growth stimulatory activity than human transferrin, and was sensitive to heat. Long-term cultivation of the cells was achieved in the defined medium supplemented with human lactoferrin only. The defined medium specifically supported the growth of various other human B- and T-lymphocytic cell lines but not the growth of various mouse lymphocytic cell lines. In lactoferrin-supplemented medium, the growth of some human cell lines were further stimulated by the addition of a combination of insulin, ethanolamine and selenium, or another combination of 2-mercaptoethanol and the above three factors. Bovine lactoferrin could be substituted for human lactoferrin.     

Identification of lactoferrin as an essential growth factor for human lymphocytic cell lines in serum-free medium

A serum-free medium supplemented with growth factor(s) was devised to grow human lymphocytic cell lines. The medium was developed using human lymphocytic cell line, Bri 7 cells. In the process of constructing the medium, human lactoferrin was found to be an essential growth factor for the cell line. Human lactoferrin has higher growth stimulatory activity than human transferrin, and was sensitive to heat. Long-term cultivation of the cells was achieved in the defined medium supplemented with human lactoferrin only. The defined medium specifically supported the growth of various other human B- and T-lymphocytic cell lines but not the growth of various mouse lymphocytic cell lines. In lactoferrin-supplemented medium, the growth of some human cell lines were further stimulated by the addition of a combination of insulin, ethanolamine and selenium, or another combination of 2-mercaptoethanol and the above three factors. Bovine lactoferrin could be substituted for human lactoferrin.     

A chemically-defined medium for the growth of a ureolytic strain of Streptococcus faecium.

A chemically-defined medium was developed which supported growth of Streptococcus faecium and permitted synthesis of urease. This streptococcus cannot utilize ammonia and needs a complex medium, but its requirements are probably provided in the rumen. The specific activity of urease was inversely related to growth and in no medium was there high growth and high urease activity. Anaerobic culture and the presence of urea in the medium were essential for urease activity, but not for growth.     

Growth of an Escherichia coli mutant deficient in respiration

An Escherichia coli mutant deficient in genes for heme biosynthesis grew in medium of initial pH 8 containing 1% tryptone and glucose under aerobic growth conditions, and its doubling time was approximately 60 min at 37°C. The growth rate was not increased under O₂-limiting conditions. When the mutant was grown in medium of initial pH 6, growth stopped at the middle of the exponential growth phase. This could be overcome and the growth yield increased by the addition of 20 mM lysine to the growth medium. Lysine did not prevent the decrease in the medium pH as growth proceeded, making it unlikely that lysine decarboxylation stimulates growth by the alkalinization of the medium. These results indicate that respiration is not obligatory for growth under aerobic conditions, but growth without respiration at low pH requires a large amount of lysine.     

An increased requirement for methionine by transformed rat liver epithelial cells in vitro

The growth of two normal and four transformed rat liver epithelial cell lines in a methionine-containing medium and a methionine-deficient medium supplemented with homocysteine was examined. The growth rates of the normal cells on the homocysteine-supplemented medium were approximately one-half the growth rates shown by the same cells in the methionine-containing medium. In contrast, three of the four transformed cell lines studied showed virtually no growth on the homocysteine-supplemented medium, although they grew quite rapidly on the methionine-containing medium. The fourth, transformed by N-methyl-N-nitrosourea, was able to grow on the homocysteine-supplemented medium at about one-third the rate as on the methionine-containing medium. Thus, transformed rat liver epithelial cells resemble other malignant cells in their reduced capacity to grow on homocysteine in the absence of methionine.     

Root organogenesis from single cells released from the root cap of Medicago sp.

Root border cells were isolated from alfalfa seedlings, and incubated in culture medium with growth regulators. Alfalfa seedlings yielded 1500±100 cells per root, and initial viability of the cells was 95±5%. Multiple cell divisions occurred in the border cells within two weeks. Cell clusters transferred to solidified medium containing growth regulators developed into rapidly growing, friable callus. When transferred to growth regulator-free medium, some of the calluses generated normal roots.Abbreviations BRD cells border cells - SHDN Schenk & Hildebrandt salts medium with growth regulators - SHO Schenk & Hildebrandt salts medium without growth regulators - NAA I-naphthaleneacetic acid     

Growth requirements and the effect of organic components of the synthetic medium on the biosynthesis of the antibiotic nisin in Streptococcus lactis strain.

A synthetic medium SM-3 has been elaborated for growth of Streptococcus lactis strain 51, which contains the minimal number of organic components required for the growth of this strain and nisin production. This medium contains 9 amino acids, 4 vitamins from B group, glucose and mineral salts. Addition of biotin to the medium stimulated the growth of the strain, while the addition of purines and/or pyrimidines had no effect. Hitherto biotin has been considered to be necessary for the growth of S. lactis and purines and pyrimidines were believed to stimulate the growth of these bacteria. In strain 51 the minimal requirements for growth were also the minimal requirements for nisin biosynthesis. Strain 51 produced 3-4 times less nisin in medium SM-3 than in a complex medium. The addition of one of four amino acids (serine, proline, cysteine or cystine) to SM-3 medium increased the amount of antibiotic produced. The addition of all four amino acids simultaneously, caused formation of nisin amounts similar to those produced in complex medium.     

Growth of mouse vaginal epithelial cells in culture: Effect of sera and supplemented serum-free media

Summary Normal mouse vaginal epithelial cells isolated from ovariectomized ca. 35-d-old BALB/cCrgl mice were grown in primary culture using collagen gel metrix and a serum-free medium composed of a 1∶1 mixture of Dulbecco’s modified Eagle’s medium and Ham’s F12 (D:H) medium supplemented with insulin (IN), epidermal growth factor (EGF), cholera toxin, transferrin, and bovine serum albumin V (BSA). Three-dimensional cellular outgrowths occurred inside the collagen gel matrix. The contribution of each factor to cell growth was examined by individual addition to the basic D:H medium and by individual deletion from the complete serum-free medium. When added individually, only IN promoted growth. Deletion of IN from the complete serum-free medium markedly, diminished growth; deletion of EGF or BSA slightly diminished growth. When horse, fetal bovine, or chicken serum was added to the basal D:H medium, only with increasing doses of horse serum was there enhanced cell growth. The effect of 17?-estradiol and diethylstilbestrol on the growth of cells was also tested, using a suboptimal medium of D:H supplemented with BSA and IN, or a minimal medium supplemented with IN alone. During the 8-d time period, addition of estrogen did not enhance cell growth in either medium. To date, we have been unable to demonstrate a mitogenic effect of estrogen; rather a dose-dependent inhibition of proliferation is seen. This investigation was supported by grants CA-05388 and CA-09041, awarded by the National Institutes of Health, DHHS, Bethesda, MD.     

培养基及其组成对水母雪莲悬浮培养细胞生长及黄酮形成的影响

8种不同的基本培养基对水母雪莲(Saussurea medusa)细胞生长和黄酮形成的影响不同。实验结果表明,MS培养基较有利于细胞生长和黄酮形成。从MS培养基修饰得到的MG和MP培养基比前者细胞生长量与黄酮产量分别提高32%和70%。碳源、氮源、植物激素对细胞生长及黄酮形成的影响较为明显。用HPLC对细胞培养物中两种有效黄酮(Jaceosidin和Hispidulin)作了定性定量分析。     

Hormonal autonomy ofArabidopsis thaliana calli

The growth ofArabidopsis thaliana calli on media without growth regulators was studied Calli under study showed autonomy for cytokmms independently whether cultivated on the light or m the dark When cultivated in intense light, they were able to grow, either transiently or permanently, on the medium without any growth regulators In the dark, they were strictly dependent on 2,4 D m the medium Both the intensity of growth and the duration of the transient growth on the medium without growth regulators m the light decreased with the duration of the previous cultivation on the medium with growth regulators The intensity of growth on the medium without grow th regulators was best and the growth was permanent m the callus clone of spontaneous origin which was never treated by growth regulators The degree of chromosomal variability (assessed as the number of chromocentres) m this callus line was lower than that in calli induced on media with growth regulators and then transferred onto medium without growth regulatois.     

Nutritionally variant streptococci from patients with endocarditis: growth parameters in a semisynthetic medium and demonstration of a chromophore.

Nutritionally variant streptococci have been characterized in the past by their growth as satellite colonies and by their nutrient requirements of cysteine or vitamin B6 for growth in complex media. To further understand the growth characteristics of these strains, we studied fresh isolates from patients with endocarditis by using chemically defined medium enriched with 2% Todd-Hewitt dialysate. Under anaerobic conditions, growth yields of the strains in this medium were comparable to those obtained from a complex medium supplemented with vitamin B6, whereas under aerobic conditions, most of the strains had higher growth yields in the semisynthetic medium. Furthermore, the requirement for cysteine and vitamin B6 in the semisynthetic medium was no greater than that of other Streptococcus species. Electron microscopic studies demonstrated normal cell wall structures in organisms grown in the semisynthetic medium as compared with abnormal and irregular cell wall thickening in organisms grown in supplemented complex medium. Finally, these strains appeared to contain a common component when grown in the semisynthetic medium as demonstrated by the appearance of a chromophore after boiling the bacteria at pH 2. Therefore, the demonstration of a medium which permits adequate growth with a normal ultrastructure of nutritionally variant streptococci will permit the further study of this group of important streptococci.     

The effect of culture medium and aeration on growth of Listeria monocytogenes at pH 4.5

Listeria monocytogenes multiplied at 20°C in medium adjusted to pH 4.5 with HCl, and the lag before growth was eliminated when the inoculum was grown to log phase in the same medium. In a tryptone soya medium with yeast extract and added glucose, growth at pH 4.5 was more rapid than in a tryptose phosphate medium, and this difference was greater in air than under nitrogen. The results show that the bacterium was capable of more rapid growth in air than under nitrogen at this pH and suggest that the tryptose phosphate medium was nutritionally limiting for growth.