INTRACELLULAR AMINO ACID CONTENT OF NEURONAL, GLIAL, AND NON-NEURAL CELL CULTURES: THE RELATIONSHIP TO GLUTAMIC ACID COMPARTMENTATION

Abstract— A protocol for the accurate determination of intracellular levels of amino acids in tissue cultured cells has been developed and used in the measurement of intracellular amino acids levels in neuronal, glial, and non-neural cell lines, with the objective of establishing morphological correlates for large and small glutamic acid compartments and of examining hypotheses for the morphological basis of glutamic acid compartmentation. This survey of intracellular amino acid levels has revealed striking differences among the cell lines tested, but these differences did not correlate with cell type, i.e. neuronal vs glial, in contrast to earlier results (R ose , 1968) based on bulk separated neuronal and pial fractions from rat brain. Amino acid levels were found to be dependent upon tissue culture conditions, yet reproducible differences could be observed when growth and experimental conditions were carefully controlled. Glutamic acid levels for various cell lines ranged from 50.8 ± 14.3 to 158 ± 8.5 nmol/mg protein. Intracellular glutamine levels demonstrated even greater difference, with values ranging from 0.8 ± 0.2 to 107 ± 42.4 nmol/mg protein. Statistically significant differences in intracellular amino acid levels between cell lines were also observed for aspartic acid, praline, glycine, alanine, valine, cystathionine, isoleucine, and leucine. A number of cell lines demonstrating highly elevated elevated levels of γ-aminobutyrate and β-alanine were identified. The significance of neuronal and glial levels of glutamic acid, glutamine and γ-aminobutyrate to models for glutamic acid compartmentation is discussed.     

Establishment, Growth kinetics, and Susceptibility to AcMNPV of Heat Tolerant Lepidop teran Cell Lines

Lepidopteran heat-tolerant(ht)cell lines have been obtained with sf-9,sf-21 and several Bombyx cells.They have a distinct karyotype,membrane lipid composition,morphology and growth kinetics from the parental cell lines.In this paper,we report the development of ht cell lines from other insect species and examination of their growth characteristics and virus susceptibility.Adaptation of cell lines sf-9,BTI-TN-5131-4(High5)and BTI-TN-MG1(MG 1)to 33℃ and 35℃ was carried out by shifting the culture temperature between 28℃ and higher temperatures by a gradual stepwise increase in temperature.The process of adaption to a higher culture temperature was accomplished over a period of 2 months.The cell lines with the temperature adaption were designated as sf9-ht33,sf9-ht35,High5-ht33,High5-ht35,MG1-ht33,MG1-ht35.These cell lines have been subcultured over 70 passages.Adaption to high temperatures was confirmed by a constant population doubling time with individual cell lines.The population doubling time of heat adapted cell lines were 1-4 h less than these of parental cell lines.Cell shapes did not show obvious change,however,the cell size of sf9-ht cells was enlarged and those of High5 and MG1 ht cells were reduced after heat adaption.When the cell lines were infected with Autographa californica nuclear polyhedrosis virus(AcMNPV)at 28℃,33℃,35℃ and 37℃,production of budded virus and occlusion bodies in each cell line was optimum at its own adapted temperature.     

Development and characerization of cell lines from subhuman primates

Summary Seven epithelial cell lines derived from kidney and 20 fibroblastic cell lines deriving from lung, heart, muscle, kidney, and skin tissue of five rhesus and six African green monkey fetuses have been established and propagated in culture. Four epithelial cell two fibroblastic cell lines resumed cell multiplication after a period of growth decline, and these lines developed cytogenetic changes and growth characteristics of cells capable of unlimited growth in vitro. Sixteen of the fibroblastic lines derived from lung, heart, muscle, or skin were characterized by a finite life consisting of a period of active cell multiplication, followed by growth decline, senescence, and cell death. Fibroblasts derived from lung appeared to have the greatest growth potential in terms of total population doublings, and fibroblastic lines from rhesus monkeys were usually capable of more doublings than similar lines from African green monkeys. All fibroblastic lines were predominantly diploid during active growth from passages 1 to 30, but several lines developed karyological changes preceding or during growth decline and senescence. All lines tested were found sensitive to a number of human viruses. All tests on these cells for microbial agents and for tumorigenicity have been negative, and the have been preserved by freezing without loss of properties. These cell lines may be useful as standardized substrates in studies requiring nonhuman primate cells. The research upon which this publication is based was performed pursuant to Contract No. NIH-69-100 with the Division of Biologics Standards of the National Institutes of Health.     

Cytoskeleton of human embryonal carcinoma cells

Monoclonal antibodies to cytoskeletal proteins were used to study the intermediate filament proteins of human embryonal carcinoma (EC) cell lines, tumors produced in nude mice from these cell lines, and surgically removed testicular germ cell tumors. It was found that all cells of tumor lines 2102Ep, 1156 and Tera 1 react with antibodies to low molecular weight keratin proteins. By immunoblotting of SDS gels it was found that these lines expressed three keratin polypeptides (40K, 45K and 52K). Clonal line NTera-2 derived from Tera-2 differed from the above listed cell lines in that only 10% of the cells expressed the 40K keratin polypeptide. Upon treatment with retinoic acid 70% of NTera-2 cells became reactive with the antibody to the 40K keratin polypeptide. All cell lines contained a small population of vimentin-positive cells. The number of vimentin-positive cells could be increased by retinoic acid treatment of NTera-2 cells or by seeding the 2102Ep cells at low cell density. Neurofilament-positive cells could be induced in the cell line NTera-2 by retinoic acid treatment. Tumors produced from NTera-2 cells injected into nude mice contained cells reacting with antibodies to keratin, vimentin, neurofilament proteins and desmin. Keratin polypeptides were immunohistochemically demonstrated in embryonal carcinoma, yolk sac carcinoma and trophoblastic components of solid human germ cell tumors. Atypical intratubular cells ('carcinoma in situ') also reacted with antibodies to keratin.     

Review: Production, characterization, and testing of banked mammalian cell substrates used to produce biological products

Summary A critical component in controlling the production of biological products derived from human and animal cell lines in the characterization and testing of banked cell substrates. The objective is to confirm the identity, purity, and suitability of these cells for manufacturing use. Quality concerns for biological products derived from cell lines originate from the presence of cellular and adventitious contaminants. Well-characterized cell banks not only permit a consistent source of production cells throughout the life of a product but also decrease the likelihood of contamination by other cell lines and adventitious agents. An important part of qualifying a cell line is choosing the appropriate testing for the presence of adventitious contaminants. The qualification of cell banks includes tests for cell identity and endogenous and adventitious microbial contaminants (bacteria, fungi, mycoplasmas, and viruses). For cells producing recombinant deoxyribonucleic acid-derived products, analysis of the expression construct at the nucleic acid level (genetic stability) is also a primary concern. The strategy for designing a safety-testing program for banked cells should be based on sound scientific principles and current regulatory guidance.     

Two new C3H mouse ascites tumor cell lines capable of proliferation in vivo and in suspension culture: Morphological,karyological, kinetic,and immunological properties

Summary The establishment of mouse tumor cell lines capable of proliferating in vivo and in suspension culture was undertaken. The MM-46 tumor line, initiated from primary mammary carcinoma arising in a C3H/He mouse, was maintained for over 100 generations in the peritoneal cavities of syngenic mice. At the 50th generation of the tumor suspension, cultures were initiated. The established cell lines, designated TMT-1 and TMT-2, were characterized in vitro and in vivo. The morphological finding indicated that TMT-1 and TMT-2 cells from mice closely resembled the MM-46 tumor cells. The oncogenic potential of the cultured cells was comparable to that of the original ascites tumor. The population doubling time of TMT-1 and TMT-2 cell lines was about 12 hr in mice, whereas the population doubling time of both cell lines lengthened to 20 hr in suspension culture. The increase of doubling time in culture was due to the prolongation of the G₁ period. The cell lines, TMT-1 and TMT-2, whether from culture or mice, possessed colony forming ability in soft agar medium. The colony forming ability of the cells decreased gradually through in vivo passages but it recovered upon recultivation of the cells from mouse to culture. Chromosome analysis and cytotoxicity test by anti-MM antiserum indicated that TMT-1 and TMT-2 cell lines closely resembled and had been derived from MM-46 tumor line. Therefore, it is possible to assay cell survival in vitro after in vivo experiments on these cells.     

Hybrid hybridoma cell lines which express anti-zeatin riboside, anti-abscisic Acid, and hybrid antibodies

Hybrid hybridoma cell lines that secreted antibodies which reacted with two distinct plant hormones, abscisic acid (ABA) and zeatin riboside (ZR) were prepared and cloned. These cell lines were derived by polyethylene glycol-mediated fusion of HAT-sensitive anti-ZR hybridoma cells with splenocytes harvested from a BALB/c mouse previously immunized with an ABA-bovine serum albumin conjugate. Chromatographic analyses indicated that these lines expressed two different isotypes, each associated with a specific immunologic reactivity, and that the populations of immunoglobulins secreted by these hybridomas included antibodies directed against each individual hapten as well as hybrid molecules which reacted simultaneously with both. Hybrid hybridomas such as these should provide antibody populations useful for simultaneous isolation of multiple plant hormones from individual plant samples.     

Immunologic characterization of hairy cell leukemias in continuous culture.

The immunobiologic characteristics of three continuous cell lines established from hairy cell leukemia cells were investigated. All three cell lines continued to produce tartrate-resistant acid phosphatase, the enzymatic marker of hairy cells. Two of these cell lines were B lymphoid in nature. They carried Fc and C receptors, had surface and internal immunoglobulin, and did not form spontaneous sheep red blood cell rosettes. Experiments employing biosynthetic radiolabeling of immunoglobulin demonstrated distinctive immunoglobulin kinetics for each of these two hairy cell lines. One cell line remained quite similar to the original hairy cells from which it was derived whereas the other B lymphoid hairy cell line had undergone a switch in the immunoglobulin isotype produced. The third hairy cell leukemia line was shown to be of thymic derivation. These cells formed spontaneous sheep red blood cell rosettes and did not carry Fc or C receptors. The spontaneous sheep red blood cell rosette-forming cells contained tartrate-resistant acid phosphatase. They did not possess surface on internal immunoglobulin and did not synthesize immunoglobulin in vitro. Hairy cell leukemia cells maintained in permanent cell culture retain their immunobiologic properties and offer the opportunity for indepth study of these unusual cells.     

Characterization of established,cell lines derived from mutagen-sensitiveDrosophila strains

Summary Six established cell lines have been generated from embryos ofDrosophila melanogaster homozygous for different X-linked mutations. Four of these mutants, confer hypersensitivity to chemical mutagens in larvae. The cell lines derived from the two mutageninsensitive stocks, serve as controls in the analyses of DNA metabolism. One cell line (UCD-Dm-mei-9-2) is uniquely identified by a strong hypersensitivity to ultraviolet radiation. Another (UCD-Dm-mus104-1) expresses an enzyme variant not found in the other lines. The population doubling time for these cultures varies between 24 and 47 h. Labeling indices of 24.4 to 37.5% were found. The duration of the S phase in one of the control cell lines is estimated to be about 9 h. Karyotype stability was monitored for five lines over a period of about 1 y. In general these cultures each, became hypotetraploid with a preferential loss of the Y and fourth chromosomes. DNA synthesis in two of the lines fails to exhibit the pattern of sensitivity to mutagens or caffeine that is observed in the corresponding primary cultures. In primary cultures three classes of cells can be identified by autoradiography. About 50% of the cells label at a moderate rate, 20% do not label within the first 1.5 d of culture, and the remaining cells exhibit a burst of labeling shortly after the cultures are initiated. This research was supported by NIH Grants GM16298 and GM22221 and by DOE Contract AT(04-3)-34 PA 210.     

Isoenzyme pattern of acid phosphatase in epstein-barr-virus-DNA positive permanent growing lymphoid cell lines (author's transl)]

The expression of acid phosphatases is cytochemically one of the most important features in permanent growing B-cell-lines. In few cell lines acid phosphatase is resistant against tartrate. Tartrate resistant isoenzyme 5 with components a and b can be demonstrated in monocytes, lymphocytes, chronic lymphatic leucemic cells and especially in hairy cells as well as in cell lines derived from a healthy donor. Fractionation of acid phosphatase by gelelectrophoresis in separated lymphocytes demonstrates especially isoenzyme 3, in separated macrophages isoenzyme 4. Isoenzyme 4 could not be detected in several cell lines. It is therefore concluded that these cell lines are probably derived from lymphocytic precursors. Cell lines with isoenzyme 4 may be the result of a facultative hybridisation between lymphocytes and monocytes. Profiles of acid phosphatases in virus-negative cell lines (Ramos, BJAB) were not significantly altered by conversion with EBV.     

Selection, characterization and regeneration of hydroxyproline-resistant cell lines of Solanum tuberosum: Tolerance to NaCl and freezing stress

Sixty-seven hydroxyproline-resistant (hyp^r) cell lines were selected from cell suspensions of a diploid potato ( Solanum tuberosum L., clone H²578) after plating on 5 and 10 m M hydroxyproline (hyp). Resistant colonies were obtained with a spontaneous frequency of 2.9×10⁻⁶. No clear influence could be shown from treatment with N-ethyl-N-nitrosourea (10 or 50 μ M ). Ninety % of the variant lines contained more proline than the wild type when cells were grown away from hyp for 1 month. Total free amino acid content was increased 2.2 to 6.8 times. When the lines were grown for another 2–5 months on non-selective medium, the content of proline and other amino acids and hyp resistance decreased. After this period the values were, however, still substantially higher than in the wild type. When tested for growth on media with other amino acid analogues (azetidine-2-carboxylic acid and dehydroproline, analogues of proline; aminoethyl-cysteine, analogue of lysine and 3-fluorotyrosine, analogue of tyrosine) and on media with inhibitory concentrations of lysine + threonine. lines H4a and H4b4 were cross resistant to these compounds. When tested on media with inhibitory NaCl concentrations, variant lines H2a, H4a, and H6 showed better tolerance than the wild type. One variant cell line (H4a) was successfully regenerated into plants. Preliminary results showed an increased frost tolerance in the leaves of these plants (−4.5°C compared to −3°C for the wild type), accompanied by a higher leaf proline content. Callus initiated from leaves of the regenerated clones was more resistant to hyp than wild type callus, indicating that the variant trait might be due to a mutation.     

Synthesis, surface deposition, and secretion of immunoglobulins by Abelson virus-transformed lymphosarcoma cell lines.

Three Abelson virus-transformed lymphoma cell lines were established in tissue culture and the immunoglobulin biosynthesis by these cell lines was studied. Two of the cell lines (ABLS-1 and ABLS-5) were found to synthesize monomeric IgM molecules which were deposited in the cell membrane, probably to serve as an antigen receptor. The third cell line (ABLS-8) was found to synthesize membrane-associated IgM as well as cellular IgG molecules. In addition, these cell lines were found to synthesize a protein of 35,000 molecular weight which is also membrane-associated and which has the capability to bind the immunoglobulin (MAID). It is speculated that this protein might play a role in adapting the receptor immunoglobulin molecule to the hydrophobic environment of the cell membrane. The kinetics of amino acid incorporation into immunoglobulins by these cell lines show that they produce immunoglobulins at a rate which is two orders of magnitude smaller than plasmacytoma cells (MOPC 104E). These results suggest that Abelson virus transforms thymus-independent lymphocytes in various stages of maturation and these lymphocytes might be of B cell origin. The T lymphoma (P1798) used as a control cell line was found occasionally to produce minute amounts of immunoglobulin.     

Establishment,growth kinetics,and susceptibility to AcMNPV of heat tolerant lepidopteran cell lines

Lepidopteran heat-tolerant (ht) cell lines have been obtained with sf-9, sf-21 and several Bombyx cells. They have a distinct karyotype, membrane lipid composition, morphology and growth kinetics from the parental cell lines. In this paper, we report the development of ht cell lines from other insect species and examination of their growth characteristics and virus susceptibility. Adaptation of cell lines sf-9, BTI-TN-5B1-4 (High5) and BTI-TN-MG1 (MG1) to 33°C and 35°C was carried out by shifting the culture temperature between 28°C and higher temperatures by a gradual stepwise increase in temperature. The process of adaption to a higher culture temperature was accomplished over a period of 2 months. The cell lines with the temperature adaption were designated as sf9-ht33, sf9-ht35, High5-ht33, High5-ht35, MG1-ht33, MG1-ht35. These cell lines have been subcultured over 70 passages. Adaption to high temperatures was confirmed by a constant population doubling time with individual cell lines. The population doubling time of heat adapted cell lines were 1–4 h less than these of parental cell lines. Cell shapes did not show obvious change, however, the cell size of sf9-ht cells was enlarged and those of High5 and MG1 ht cells were reduced after heat adaption. When the cell lines were infected with Autographa californica nuclear polyhedrosis virus (AcMNPV) at 28°C, 33°C, 35°C and 37°C, production of budded virus and occlusion bodies in each cell line was optimum at its own adapted temperature.     

Lysosomal acid hydrolases in established lymphoblastoid cell lines,transformed by Epstein-Barr virus,from patients with genetic lysosomal storage diseases

Summary Lysosomal acid hydrolases were determined in established lymphoblastoid cell lines, transformed in vitro by Epstein-Barr virus (EBV) from lymphocyte-rich cell populations isolated from the peripheral blood of patients with genetic lysosomal storage diseases—Hurler syndrome, Scheie syndrome, G_M1-gangliosidosis type 1 and type 2, Tay-Sachs disease, and I-cell disease—and from obligate heterozygotes for these diseases.The respective enzyme activity was undectectable in lymphoblastoid cells from the patients, but not from controls. Obligate heterozygotes could not always be distinguished from controls in lymphoblastoid cells as well as in leukocytes. These results suggest that established lymphoblastoid cell lines are useful material for the enzymatic study of genetic lysosomal storage diseases.     

视黄酸对胃癌细胞周期的调控

视黄酸(RA)能够抑制许多类型癌细胞生长、诱导细胞凋亡和调节细胞周期。本文研究了全反式视黄酸(ATRA)对人胃癌细胞的作用机理。结果表明,ATRA通过诱导细胞滞留在G_0/G_1期而显著抑制胃癌细胞生长,但ATRA不能诱导胃癌细胞凋亡;ATRA调控细胞周期与c-myc、磷酸化Rb水平的下调和p21~(WAF1/CIP1)、p53水平的上调有关,而cyclinD_1和CDK_4水平没有明显变化。在RA抗性细胞中,ATRA不能调节这些基因表达。结果证实,ATRA对胃癌细胞生长抑制与其诱导细胞滞留在G_0/G_1期有关,而与细胞凋亡的诱导无关,许多重要的、与周期相关的分子,包括cmyc、p21~(WAF1/CIP1、p53和Rb等参与细胞周期的调控。     

Palmitic Is the Main Fatty Acid Carried by Lipids of Detergent-Resistant Membrane Fractions from Neural and Non-Neural Cells

Lipids extracted from detergent-resistant membrane fractions, thought to derive from membrane domains, were analyzed for fatty acid composition. The proportion of palmitic acid in fractions isolated from neurons (cerebellar granule cells) and from neural-like cell lines (neuroblastoma-glioma NG108-15) nearly doubled (reaching about 54% of total fatty acids) with respect to cell WCL, indicating their enrichment in palmitic acid-carrying lipids. The proportion of palmitic acid in detergent-resistant fractions obtained from caveolin-transfected NG108-15 cells was comparable with that obtained from caveolin-negative cells, ruling out a specific role of this protein in recruiting palmitoylated lipid species. The enrichment in palmitic acid was remarked also in membrane fractions isolated from non-neuronal cell lines (A431) using either detergents or detergent-free techniques. Lipid fractionation and mass spectrometry experiments show that palmitic acid–rich phosphatidylcholine species are responsible of the peculiar fatty acid composition of these fractions. All together these results suggest that the enrichment in palmitic acid–rich phosphatidylcholine species is a common feature of neural and non-neural cell lines and may play a major role in the biogenesis of membrane domains.     

Differences in sialyl transferase activity and in concanavalin-A agglutination between T and B lymphoblastoid cell lines.

The concanavalin A agglutination patterns, sialyl transferase activity and sialic acid content were studied for cultured lymphoblastoid cell lines possessing either T or B surface markers. Concanavalin A caused marked agglutination of the two B cell lines studied, Raji and SB, while the two T cell lines, HSB-2 and CCRF-CEM, failed to agglutinate with this lectin. The surface sialyl transferase activity of the two B lines was significantly higher than on the two T lines studied. In contrast, the total cellular sialic acid content or the surface sialic acid that was released from the T and B cell lines by neuraminidase was not significantly different. This study indicates that T and B lymphoblastoid cells possess different levels of surface located sialyl transferase activity and display different agglutination patterns with Con A. Perhaps these assays can be of value in differentiating various classes of neoplastic lymphoid cells.     

A comparative study of glycosaminoglycans in cultures of human, normal and malignant glial cells.

The glycosaminoglycans (GAG) of human cultured normal glial and malignant glioma cell lines were studied using 35S-sulphate or 3H-glucosamine as markers. 35S-labelled GAG were assayed by precipitation with cetylpyridinium chloride; 3H-labelled sulphated GAG and 3H-labelled hyaluronic acid were quantitated after separation on a DEAE-cellulos column. The net production of GAG and the distribution, composition and turnover of GAG were similar in all of the normal cell lines tested, but showed a great variability in the malignant cell lines. Most of the glioma cell lines produced more hyaluronic acid and less sulphated GAG than the normal cell lines, but exceptions were noted. The GAG of the trypsin susceptible (pericellular pool of normal glial cells consisted mainly of heparan sulphate with only minor amounts of other GAG. The analogous material of most glioma cells showed hyaluronic acid as the major GAG. Material liberated by trypsin from EDTA-detached cells (membrane fraction) was enriched in heparan sulphate as compared to the entire pericellular pool. Substrate attached material (SAM) left with the plastic dish after EDTA treatment of normal cultures was rich in heparan sulphate, whereas SAM of glioma cells lacked heparan sulphate or showed greatly reduced amounts of this component. Release of newly synthesized GAG to the extracellular medium was a rapid process in the normal cells but was more or less delayed in the glioma cells. The extracellular medium of the malignant glioma cultures was consistently poor in dermatan sulphate, as compared to that of normal cultures.