Aedes novalbopictus: establishment and characterization of larval cell lines

Two diploid cell lines were established from larval tissues of the mosquito Aedes novalbopictus. Many morphologically different types of cells were detected in primary cultures. However, only three types of cells became established in the cell lines. They were: epithelial-like cells (80–90%), fibroblast-like cells (5–10%), and giant cells (5–10%). Cell number increased about 15-fold during the first 6 days of culture and the population doubling time during the period of active growth was 18 hr. Seventy to 80% of the cells were diploid (2n = 6) and the rest were tetra-or polyploids. Cells from these two cultures so far (December, (1971)) have been subcultured 36 and 34 times, respectively. The growth pattern and general morphologic features of the cells of A. novalbopictus cultures closely resembled those of A. albopictus cultures.     

Parasexuality and Ploidy Change in Candida tropicalis

Candida species exhibit a variety of ploidy states and modes of sexual reproduction. Most species possess the requisite genes for sexual reproduction, recombination, and meiosis, yet only a few have been reported to undergo a complete sexual cycle including mating and sporulation. Candida albicans, the most studied Candida species and a prevalent human fungal pathogen, completes its sexual cycle via a parasexual process of concerted chromosome loss rather than a conventional meiosis. In this study, we examine ploidy changes in Candida tropicalis, a closely related species to C. albicans that was recently revealed to undergo sexual mating. C. tropicalis diploid cells mate to form tetraploid cells, and we show that these can be induced to undergo chromosome loss to regenerate diploid forms by growth on sorbose medium. The diploid products are themselves mating competent, thereby establishing a parasexual cycle in this species for the first time. Extended incubation (>120 generations) of C. tropicalis tetraploid cells under rich culture conditions also resulted in instability of the tetraploid form and a gradual reduction in ploidy back to the diploid state. The fitness levels of C. tropicalis diploid and tetraploid cells were compared, and diploid cells exhibited increased fitness relative to tetraploid cells in vitro, despite diploid and tetraploid cells having similar doubling times. Collectively, these experiments demonstrate distinct pathways by which a parasexual cycle can occur in C. tropicalis and indicate that nonmeiotic mechanisms drive ploidy changes in this prevalent human pathogen.     

Pyruvate secreted by human lymphoid cell lines protects cells from hydrogen peroxide mediated cell death

Reactive oxygen species (ROS) released from polymorphonuclear leukocytes and macrophages could cause DNA damage, but also induce cell death. Therefore inhibition of cell death must be an important issue for accumulation of genetic changes in lymphoid cells in inflammatory foci. Scavengers in the post culture medium of four lymphoid cell lines, lymphoblastoid cell lines (LCL), Raji, BJAB and Jurkat cells, were examined. Over 80% of cultured cells showed cell death 24 h after xanthine (X)/xanthine oxidase (XOD) treatment, which was suppressed by addition of post culture medium from four cell lines in a dose-dependent manner. H₂O₂ but not O^·-₂ produced by the X/XOD reaction was responsible for the cytotoxity, thus we used H₂O₂ as ROS stress thereafter. The H₂O₂-scavenging activity of post culture media from four cell lines increased rapidly at the first day and continued to increase in the following 2–3 days for LCL, Raji and BJAB cells. The scavenging substance was shown to be pyruvate, with various concentrations in the cultured medium among cell lines. Over 99% of total pyruvate was present in the extracellular media and less than 1% in cells. α-Cyano-4-hydroxycinnamate, a specific inhibitor of the H⁺-monocarbohydrate transporter, increased the H₂O₂-scavenging activity in the media from all four cell lines via inhibition of pyruvate re-uptake by cultured cells from the media. These findings suggest that lymphoid cells in inflammatory foci could survive even under ROS by producing pyruvate, so that accumulation of lymphoid cells with DNA damage is possible.     

Homoeologous chromosomes of Xenopus laevis are highly conserved after whole-genome duplication

It has been suggested that whole-genome duplication (WGD) occurred twice during the evolutionary process of vertebrates around 450 and 500 million years ago, which contributed to an increase in the genomic and phenotypic complexities of vertebrates. However, little is still known about the evolutionary process of homoeologous chromosomes after WGD because many duplicate genes have been lost. Therefore, Xenopus laevis (2n=36) and Xenopus (Silurana) tropicalis (2n=20) are good animal models for studying the process of genomic and chromosomal reorganization after WGD because X. laevis is an allotetraploid species that resulted from WGD after the interspecific hybridization of diploid species closely related to X. tropicalis. We constructed a comparative cytogenetic map of X. laevis using 60 complimentary DNA clones that covered the entire chromosomal regions of 10 pairs of X. tropicalis chromosomes. We consequently identified all nine homoeologous chromosome groups of X. laevis. Hybridization signals on two pairs of X. laevis homoeologous chromosomes were detected for 50 of 60 (83%) genes, and the genetic linkage is highly conserved between X. tropicalis and X. laevis chromosomes except for one fusion and one inversion and also between X. laevis homoeologous chromosomes except for two inversions. These results indicate that the loss of duplicated genes and inter- and/or intrachromosomal rearrangements occurred much less frequently in this lineage, suggesting that these events were not essential for diploidization of the allotetraploid genome in X. laevis after WGD.     

Characterization of immortalized mouse granulosa cell lines

Summary Cell cultures of primary mouse granulosa cells were transfected with a v-myc-containing plasmid, and the resulting stable cell lines were tested for their steroidogenic properties and physiologic status. Granulosa cells were obtained from 22-day-old NMRI mice injected with 8 IU pregnant mare serum gonadotropin i.p. 2 days earlier. In Passage 1 the cells were transfected with pSVv-myc using calcium phosphate precipitation or lipofectin. The 3β- and 17β-hydroxy steroid dehydrogenase activity was visualized in control cultures. The three cell lines obtained have been in culture for over 1 yr and have been subcultured for more than 90 passages. The cell line GRM01, with a doubling time of 37±3 h and a diploid modal chromosome number, produced progesterone, estradiol, as well as inhibinlike and activinlike material under basal conditions. A combination of follicle-stimulating hormone and luteinizing hormone was able to increase the secretion of progesterone. GRM01L, a fast growing clone of the GRM01 line with a doubling time of 10±1 h, retained only the capacity to produce activinlike material and transforming growth factor-β, and it was the only one with a tumorigenic capacity. Epidermal growth factor, insulin, and interleukin-6 were able to induce the [³H]thymidine incorporation into DNA in these two cell lines. GRM02, with a doubling time of 36±2 h and a hypertriploid modal chromosome number, produced progesterone and activinlike and inhibinlike material. Follicle-stimulating hormone and luteinizing hormone were able to enhance the secretion of progesterone. For this cell line, only insulin was shown to induce [³H]thymidine incorporation into DNA.     

Studies on the cultivation of mammalian cell lines in a serum-free,chemically defined medium

Summary An improved chemically defined, serum-free medium for the cultivation of a variety of continuous cell lines has been developed. Eight lines of human origin, three lines of nonhuman primate origin, and five lines of rodent origin have been cultured serially for as long as a year in the medium. Growth rates of several serial lines resulted in as much as 20- to 30-fold increases per week. Hormones such as insulin, cortisol, and thyroxine significantly improved growth of cultures in the defined medium. Vitamin B₁₂ and biotin were required for growth. Lipids such as oleic acid, lecithin, and cholesterol also promoted growth of several cell lines. Virtually all continuous cell lines tested grew well upon initial transfer into the serum-free defined medium. Most cell lines could be serially subcultured rapidly with little evidence that selection of rare cell types was necessary for growth in the defined medium. However, a few cell lines such as the BHK-21 (hamster) cell and the AKR (mouse embryo) cell required prolonged periods (4 to 8 weeks) of culturing before rapid growth occurred. Primary cell cultures and other diploid cells such as human fibroblast (strain WI-38) could not be subcultured successfully in the present medium.     

A set of stage-dependent embryonic antigens expressed in cell cultures of BALB/c mouse embryos and in transformed cell lines

A rabbit antiserum (A2) directed against the detergent-solubilized fraction of the simian virus 40-transformed mouse embryo fibroblast cell line VLM detects common antigens in primary cell cultures from BALB/c mouse embryos and in transformed cell lines from various species. Positively reacting cell cultures show a set of polypeptides with molecular weight species p86, p74, p68, p46, p42, p40, and p35. As tested by Western blotting procedures, all immunoprecipitated proteins carry immunologically reactive determinants. By analysis with two-dimensional gel electrophoresis, all precipitated polypeptides show charge heterogeneities. Concerning the two major members of the protein set, p40 consists of at least four subspecies with isoelectric points in the range of pH 6.2-6.8, whereas p35 is composed of two subspecies focusing between pH 6.4 and pH 7.2. By comparison of the two-dimensional patterns of p35 of various transformed cell lines, a basic (pH 6.6-7.2) and an acidic (6.4-6.6) charge type of p35 could be observed. Comparative analyses of primary cell cultures from 12-16-day mouse embryos show the immunoprecipitated set of polypeptides only in the 16-day embryo cell cultures. After six further propagations, these cells express the immunoreactive proteins as strongly as the primary cell cultures. In embryonic cell cultures of day 14 of gestation the expression of this set of antigens is induced only when cells are propagated at least six times. Under identical conditions these proteins could not be induced in cell cultures of 18-day-old mouse embryos. None of the polypeptides could be immunoprecipitated from primary mouse kidney cell cultures of 12-day-old mice even when the cultures were propagated at least 15 times. This set of polypeptides is also present in simian virus 40-transformed cells of hamster, rat, monkey, and human origin. These findings suggest that in simian virus 40-transformed mouse cells, in addition to p53, the synthesis of other embryonic antigens is reactivated. The presence of the described set of polypeptides in polyoma virus-transformed cells of rat and mouse origin and in cell lines derived from malignant human tumors might indicate common functions in metabolic patterns of transformed cells.     

Visual selection and maintenance of the cell lines with high plant regeneration ability and low ploidy level in Dianthus acicularis by monitoring with flow cytometry analysis

Efficient plant regeneration system from cell suspension cultures was established in D. acicularis (2n=90) by monitoring ploidy level and visual selection of the cultures. The ploidy level of the cell cultures closely related to the shoot regeneration ability. The cell lines comprising original ploidy levels (2C+4C cells corresponding to DNA contents of G1 and G2 cells of diploid plant, respectively) showed high regeneration ability, whereas those containing the cells with 8C or higher DNA C-values showed low or no regeneration ability. The highly regenerable cell lines thus selected consisted of compact cell clumps with yellowish color and relatively moderate growth, suggesting that it is possible to select visually the highly regenerable cell lines with the original ploidy level. All the regenerated plantlets from the highly regenerable cell cultures exhibited normal phenotypes and no variations in ploidy level were observed by flow cytometry (FCM) analysis.     

Establishment,characterization and viral susceptibility of two cell lines derived from leopard wrasse Macropharyngodon geoffroy

Two new fish cell lines were established from skin (LWSK) and fin (LWFN) of leopard wrasse Macropharyngodon geoffroy. These cells grew optimally at 25° C in Leibovitz‐15 medium supplemented with 10% foetal bovine serum. Proliferation of M. geoffroy cells remained serum dependent up to cell passage 16, and cell‐plating efficiency ranged from 12 to 16%. Karyotypic analysis of these new cell lines at cell passage 8 indicated that both cell lines remained diploid with a peak chromosomal count of 144. PCR amplification of 16S mitochondrial DNA and the subsequent analysis confirmed that these cell lines were indeed derived from M. geoffroy. Results of viral challenge assays revealed that both LWSK and LWFN shared patterns of viral susceptibility similar to that of six fish viruses tested: LWSK and LWFN cells were highly permissive to channel catfish virus, spring viremia carp virus and snakehead rhabdovirus with high‐yield virus production ranging from 10^7·18±0·17 to 10^8·37±0·16 TCID₅₀ ml^?1 (mean ± s.d .). These newly established cell lines would be useful in attempts to isolate and study aquatic viruses, particularly the viral aetiology of green turtle fibropapilloma as M. geoffroy is known to be one of the common cleaner fish of green sea turtles.     

Establishment of functional epithelial cell lines from a rat thymoma and rat thymus

Summary Seven clonal epithelial cell lines from a thymoma of an (ACI/NMs×BUF/Mna)F1 rat and seven clonal epithelial cell lines from an ACI/NMs rat thymus were established in a medium containing 1 μM dexamethasome (DM) and were characterized cytologically. Long-term treatment of DM stabilized the epithelial nature of these epithelial cells irreversibly. The established cell lines showed a polygonal shape, were positively stained with antikeratin antiserum and had tonofilaments and desmosomes. Species of their keratin paptides were the same as those of normal thymic epithelial cells in primary cultures. The cell lines were positively stained with Th-4 monoclonal antibody which preferentially stains the medullary epithelial cells of the thymus, but not with Th-3 which preferentially stains the subcapsular and cortical epithelial cells of the thymus. The cells from the rat thymoma were much large than those from the normal thymus, as reflected in their primary cultures. No transformed phenotypes, such as high growth rate, high saturation density anchorage independency, low serum dependency and so on, were found on the cell lines from the thymoma as in the cell lines from the normal thymus by in vitro assays. DNA synthesis of the thymic lymphocytes was stimulated by culturing with a line of rat thymoma with no lectins. Thymic lymphocytes strongly bound on the cell lines from the thymoma and changed the shape of the cells. These cell lines may be useful to investigate the mechanism of thymomegenesis and the interactions between epithelial cells and thymocytes in the rat thymoma.     

The selection of cultured plant cell lines producing high levels of biotin

We have found that biotin is synthesized in many species of cultured plant cells, e.g. Lavandula vera Labiatae), Nicotiana tabacum (Solanaceae) and Glycine max Leguminosae). Cultured green L. vera cells grown under light contained the greatest amounts of free biotin of the cells studied although the specific amounts varied among the cell lines. Cell lines were selected after their free biotin contents had been analysed. Cells containing large amounts of free biotin were cultured repeatedly, analysed and reselected. Lines with high levels of free biotin were obtained from cells which survived on a medium containing pimelic acid and l-alanine or from gamma irradiated cells. One L. vera cell line obtained from irradiated cells contained seven times the amount of free biotin found in the original unselected cultured cells and four and a half times that found in the leaves.     

In vitro isolation and establishment of new embryonal cell lines from rat nephroblastoma

Summary Two mixed cell lines designated REN-1 and REN-2 were established successfully in continuous in vitro culture from subcutaneously propagated transplant tissue derived from a nephroblastoma which had occurred spontaneously in an Nb hooded rat. In monolayer culture the lines consisted of clumps, islands, and cords of densely crowded, small basophilic cells of epithelioid character, together with mesenchymelike cells occupying the intervening spaces. The proportion of epithelioid cells to mesenchyme could be enhanced by high seeding densities and the intermittent application ofcishydroxyproline to the medium. A third cell form with the appearance of more mature epithelium was observed as a later development in one of the monolayer cultures (REN-1). This larger epithelial cell and a homogeneous mesenchymal population were isolated as cloned cell lines from REN-1 (REN-1-C/2 and REN-1-C/1, respectively), but attempts to clone the dominant basophilic epithelioid cell were not successful. Light and electron microscopy indicated the small, basophilic epithelioid cells to be morphologically consistent with the undifferentiated embryonal blast cells of the parent tumor. They were a distinctive population unlike known malignant cell lines representative of chemically transformed rat kidney mesenchyme and epithelium. The mesenchymelike cells present in the uncloned cell lines, and cloned in REN-1-C/1, were fibroblasts by ultrastructural criteria and therefore distinct from the epithelioid moiety. Ultrastructurally the larger epithelium cloned in REN-1-C/2 displayed the features of differentiated renal epithelium. Subcutaneous transplantation in syngeneic and allogeneic recipients showed the uncloned parent cell lines containing the basophilic epithelioid population to be highly tumorigenic, producing rapidly growing tumors that were unequivocal nephoblastomas. The mesenchymal clone, REN-1-C/1, was also tumorigenic but, consistent with its fibroblastic nature, produced only fibrosarcomas on transplantation. The mature epithelial clone, REN-1-C/2, transplanted as an anaplastic carcinoma with limited tubule formation. Because of their distinctive morphology and growth behavior, and their ability to proliferate into nephroblastomas on transplantation, the dominant population of basophilic epithelioid cells in the parent uncloned cell lines is considered to represent neoplastic kidney cells of undifferentiated embryonal type. The possible host origin of the mesenchymal population from the supporting stroma of the original transplantation tumor is suggested in discussion. This investigation was supported by research grants CA-24216 and CA-12227 awarded by the National Cancer Institute, Department of Health and Human Services, and in part by the National Cancer Institute of Canada.     

Derivation of the clonal‐cell lines from Siberian sturgeon (Acipenser baerii) head‐kidney cell lines and its applicability to foreign gene expression and virus culture

This study was conducted to establish and characterize the clonal‐cell lines from Siberian sturgeon Acipenser baerii head‐kidney tissues and to evaluate its applicability as a research tool. From the culture of A. baerii head‐kidney derived cells, 10 cell lines were established first and then eight clonal‐cell lines were derived from clonal growth and colony expansion of two cell lines that showed significant high colony‐forming ability. All eight clonal‐cell lines were morphologically similar and grew stably under monolayer culture but their growth rates were significantly different. They possessed diploid DNA contents, expressed epithelial cell‐related genes and showed strong anchorage dependency to substrates. When a clonal‐cell line was transfected separately with three plasmid vectors including fluorescent reporter genes driven by cytomegalovirus, marine medaka Oryzias dancena β‐actin or A. baerii β‐actin promoter, the cell lines expressed fluorescent signals regardless of promoter types. The cells harbouring foreign genes could be expanded to stable cell lines under drug selection and then they additionally could form the extensively proliferating colonies at low‐density culture. Finally, the clonal‐cell lines showed the susceptibility to viral haemorrhagic septicaemia virus (VHSV). Collectively, the clonal‐cell lines from A. baerii head kidney were established and these cell lines will be able to provide an excellent in vitro system for various biological studies in this fish species.     

Cultivation of mosquito cell lines in serum-free media and their effects on dengue virus replication

Summary Seven mosquito cell lines from five species (Aedes aegypti, Ae. albopictus, Ae. pseudoscutellaris, Culex tarsalis, andToxorhynchites amboinensis) were adapted to three kinds of serum-free media (SEM), which were composed of equal volumes of tryptose phosphate broth and of either Leibovitz (L15) medium, Eagle’s minimum essential medium, or Medium 199 with Hanks’ salts. Population growth rates of the cells cultivated in the SMFs were generally slower than those of original cell cultures maintained in conventional media containing bovine sera. A karyological study showed a significant shift to heteroploidy in two of the four cell lines examined. Four SMF-adapted sublines were compared with parental cultures for replication of dengue viruses.Ae. aegypti RML-12,Ae. albopictus C6/36,Ae. pseudoscutellaris AP-61, andTx. amboinensis TRA-171 demonstrated different levels of alteration in virus replication ranging from lower titers (as inAe. albopictus C6/36) to comparable or higher titers (as inAe. aegypti RML-12) when they were simultaneously inoculated with four dengue serotypes. Use of trade names and commercial sources is for identification only and does not constitute endorsement by the Public Health Service or by the U.S. Department of Health and Human Services.     

Human embryonic stem cell lines derived from the Chinese population

Six human embryonic stem cell lines were established from surplus blastocysts. The cell lines expressed alkaline phosphatase and molecules typical of primate embryonic stem cells, including Oct-4, Nanog, TDGF1, Sox2, EBAF, Thy-1, FGF4, Rex-1, SSEA-3, SSEA-4, TRA-1-60 and TRA-1-81. Five of the six lines formed embryoid bodies that expressed markers of a variety of cell types; four of them formed teratomas with tissue types representative of all three embryonic germ layers. These human embryonic stem cells are capable of producing clones of undifferentiated morphology, and one of them was propagated to become a subline. Human embryonic stem cell lines from the Chinese population should facilitate stem cell research and may be valuable in studies of population genetics and ecology.     

Haploid and diploid cell cultures from a haplo-diploid insect

Summary

This is the first report of haploid and diploid cell culture from the haplo-diploid parasitoid wasp, Mormoniella vitripennis. Cells were cultured from haploid and diploid wasps by collecting populations of eggs from virgin females (unfertilized, haploid, parthenogenetic eggs) and mated females (mostly fertilized, diploid eggs). Eggs were surface sterilized in 70% ethanol, followed by 50% Chlorox, and rinsed in phosphate buffered saline; larvae were allowed to hatch in culture. Larval cells were dissociated and cultured at 28°C in the presence of Grace's medium supplemented with fetal bovine serum. Most cells in the HMV (predominantly haploid) and DMV (predominantly diploid) cell cultures grew in suspension in the first week, formed monolayers of fibroblasts and epithelial cells by the second week in culture, and continued to grow in monolayers and vesicle-like structures for up to three months. Chromosome analysis of HMV. cells demonstrated over 70% haploid cells, with five chromosomes (N=5). The remainder were aneuploid. No diploid cells (2N= 10) were found in the HMV cell culture. Chromosome analysis of DMV cultures revealed 62% diploid, with ten chromosomes; 13% were haploid, with five chromosomes; the remainder were aneuploid. These data confirm that haploid and diploid cells can be cultured from a haplo-diploid insect species. The HMV cells which are predominantly haploid, and DMV cells which are predominantly diploid may be valuable models for the study of cellular and gene activity in haploid and diploid genetic milieux.     

Comparison of nuclear polyhedrosis virus replication in five lepidopteran cell lines

Comparative studies were performed on the replication of the Autographa californica nuclear polyhedrosis virus in cell lines from Estigmene acrea, BTI-EAA; Lymantria dispar, IPLB-LD64BA; Mamestra brassicae, IZD-MB0503; Spodoptera frugiperda, IPLB-SF1254; and Trichoplusia ni, TN-368. Significant differences were observed in the amount of virus obtained from the cell lines, with M. brassicae and T. ni producing more polyhedra than the other lines. These two cell lines also produced nonoccluded virus most rapidly, followed by S. frugiperda, E. acrea, and L. dispar. Sensitivities of the cell lines to infection by the virus, as determined by plaque formation, followed the same pattern, with M. brassicae being most sensitive and L. dispar least so. The T. ni cell line produced polyhedra which were more pathogenic to T. ni larvae than those from the other cells. These differences have important implications in the application of cell cultures in the development of microbial insecticides.     

The electrical block to polyspermy induced by an intracellular Ca2+ increase at fertilization of the clawed frogs,Xenopus laevis and Xenopus tropicalis

Polyspermy blocking, to ensure monospermic fertilization, is necessary for normal diploid development in most animals. We have demonstrated here that monospermy in the clawed frog, Xenopus tropicalis, as well as in X. laevis, is ensured by a fast, electrical block to polyspermy on the egg plasma membrane after the entry of the first sperm, which is mediated by the positive‐going fertilization potential. An intracellular Ca²⁺ concentration ([Ca²⁺]_i) at the sperm entry site was propagated as a Ca²⁺ wave over the whole egg cytoplasm. In the X. tropicalis eggs fertilized in 10% Steinberg's solution, the positive‐going fertilization potential of +27 mV was generated by opening of Ca²⁺‐activated Cl^?‐channels (CaCCs). The fertilization was completely inhibited when the egg's membrane potential was clamped at +10 mV and 0 mV in X. tropicalis and X. laevis, respectively. In X. tropicalis, a small number of eggs were fertilized at 0 mV. In the eggs whose membrane potential was clamped below ?10 mV, a large increase in inward current, the fertilization current, was recorded and allowed polyspermy to occur. A small initial step‐like current (IS current) was observed at the beginning of the increase in the fertilization current. As the IS current was elicited soon after a small increase in [Ca²⁺]_i, this is probably mediated by the opening of CaCCs. This study not only characterized the fast and electrical polyspermy in X. tropicalis, but also explained that the initial phase of [Ca²⁺]_i increase causes IS current during the early phase of egg activation of Xenopus fertilization.     

Development and characterization of three new diploid cell lines from Labeo rohita (Ham.)

Development of cell lines from fish for identifying the pathogenesis of viral diseases and for vaccine production against viral and bacterial diseases is imperative where they are of commercial importance. Three new diploid fish cell lines (RF, RH, and RSB) were developed from fin, heart, and swim bladder of an Indian major carp, Labeo rohita, commonly called Rohu. All the cell lines were optimally maintained at 28°C in Leibovitz‐15 medium supplemented with 10% FBS. The propagation of RH and RSB cells was serum dependent, with a low plating efficiency (<16%), whereas RF cells showed 20% efficiency. The cytogenetic analysis revealed a diploid count of 50 chromosomes. The cells of RF and RSB were found to be epithelial, where as the cells of RH were mostly fibroblastic. The viability of the RF, RH, and RSB cell lines was 75, 70 and 72%, respectively after 6 months of storage in liquid nitrogen. The origin of the cell lines was confirmed by the amplification of 496 and 655 bp fragments of 16S rRNA and Cytochrome Oxidase Subunit I (COI) of mtDNA. The new cell lines would facilitate viral disease diagnosis and genomic studies. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010