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201.
Michael D. Aleo Mary L. Taub Peter A. Nickerson Paul J. Kostyniak 《In vitro cellular & developmental biology. Plant》1989,25(9):776-783
Summay Before the usefulness of a new in vitro model can be ascertained, the model must be properly defined and characterized. This
study presents the growth rate and biochemical characteristics of rabbit renal proximal tubule cells in primary culture over
a 2-wk culture period. When grown in a hormonally defined, antibiotic-free medium these cells form confluent monolayer cultures
within 7 d after plating. Multicellular done formation, an indicator of transepithelial solute transport, was expressed after
confluent cultures were formed. The activity of the cytosolic enzyme, lactate dehydrogenase, and the lysosomal enzyme,N-acetyl-glucosaminidase, increased 14- and 2-fold during the first 8 d of culture. respectively. In contrast, the activity
of a brush border enzyme, alkaline phosphatase, decreased 85% within the first 8 d of culture. Release of these enzyme markers
into the culture medium, which are routinely used to measure cytoxicity, stabilized after 8 d in culture. The ratio of cellular
protein to DNA changed according to the state of cellular growth. Values rose from 0.035 mg protein/μg DNA in preconfluent
cultures to 0.059 mg protein/μg DNA in confluent cultures. These results document the characteristics of a primary proximal
tubule cell culture system for future studies in in vitro toxicology.
This paper was resented at a Symposium on the Physiology and Toxicology of the Kidney In Vitro co-sponsored by The Society
of Toxicology (SOT) and the Tissue Culture Association held at the 27th annual meeting of the SOT in Dallas, Texas in 1988.
This work was supported by grants GM 07145, The Johns Hopkins Center for Alternatives to Animal Testing, and a Sigma Xi Grants-in-Aid
of Research Award. 相似文献
202.
Lisa J. Leiderman J. Allan Tucker Vincent W. Dennis 《In vitro cellular & developmental biology. Plant》1989,25(10):881-886
Summary Proliferation and differentiation of opossum kidney cells in a serum-free defined medium was investigated and compared to
that under conditions in which fetal bovine serum FBS (10%) was employed. Monolayers were grown in Dulbecco's modified Eagle's
medium-Ham's F12 nutrient mixture containing insulin (10 μg/ml), bovine serum albumin fraction V (1 mg/ml) and fetuin (1 mg/ml).
Cells in serum-free medium seeded at 1×104 per cm2 grew to confluency within 6 to 8 d and formed hemicysts or domes at a frequency equivalent to those in serum-containing medium.
Electron microscopy of cultures grown in serum-free medium revealed polarized monolayers with the presence of microvilli and
tight junctions. The differentiated characteristics, including sodium-dependent phosphate transport, the inhibition of this
transport by parathyroid hormone (PTH), and the generation of cyclic AMP in response to PTH, were preserved in opossum kidney
cells grown in serum-free medium. 相似文献
203.
The present study examined postmetacercarial changes in the excysted metacercariae of Echinostoma caproni maintained in the defined medium Mixture 199 plus 20% calf serum for 7 days at 41 degrees C. The gas phase was atmospheric air. Each culture was inoculated with 25 excysted metacerariae. Cultures were maintained upright in closed 15 ml plastic centrifuge tubes each containing 10 ml of medium plus 200 units of penicillin/ml and 200 micrograms of streptomycin/ml. By 4 days in culture, most metacercariae had voided their excretory concretions. Organisms were clumped or solitary at the bottom of the cultures. Many organisms showed flaring of the oral collar and extension of both the collar and tegumentary spines. By 4 days in culture, posterior protuberances or bumps were noted on many of the organisms and some organisms showed abnormal vesicular growths or blebs at their posterior ends. Some mortality was noted in culture by day 5, but most organisms were still alive when the cultures were terminated on day 7. 相似文献
204.
A simple-defined medium was formulated that allows robust axenic-growth of the model mixotrophic protist Ochromonas danica at a neutral pH. This new defined medium, with a minimum number of constituents, facilitates more highly controlled studies of mixotrophic metabolism and nutrient regeneration than have previously been possible. 相似文献
205.
《European journal of protistology》2014,50(1):33-39
A colpodean ciliate was found in the faeces of experimental rabbits. It was initially cultivated in medium mixed with 2% (w/v) rabbit faeces. Subsequently, two chemically defined media, designated CA-1 and CA-2, were found to be suitable for axenical cultivation of the ciliate. The maximum abundance of the ciliate isolate in the CA media was 1–2 × 105 cells/ml. The ciliate isolate was further identified with silver impregnation and molecular analysis. Features of the left oral polykinetid, somatic dikinetids, and sliverline pattern were similar to those of Colpoda aspera as described by Foissner (1993). The 18S small subunit ribosomal RNA gene of the ciliate isolate shared 99% sequence identity with that of C. aspera, with 100% coverage, and formed a sister clade in the phylogenetic tree with the reference C. aspera isolate. In addition, the trophozoite of C. aspera could proliferate over a temperature range from 25–37 °C. When resting cysts were cultivated in CA-1 medium at 30–35 °C, 98.2% of the trophozoites were detached from the cyst wall after 7 h. 相似文献
206.
Asahi H 《Experimental parasitology》2009,121(1):22-28
Dioleoylphosphatidylcholine and other phosphatidylcholines containing different fatty acid moieties were found to increase the ability of nonesterified fatty acids (NEFA) to sustain continuous intraerythrocytic growth of Plasmodium falciparum in the presence of specific proteins. Other phospholipids, including phosphatidylethanolamine, phosphatidylserine, and phosphatidic acid, were beneficial to parasite growth. Different combinations and concentrations of NEFA tested in the presence of phospholipids and bovine albumin had variable effects on parasite growth. The most effective combination for promoting parasite growth consisted of 30 μg/ml cis-9-octadecenoic acid (oleic acid) plus 15 μg/ml hexadecanoic acid (palmitic acid). Recombinant human albumin could replace bovine or human albumin in culture media enriched with structurally defined lipids. This study therefore established a chemically defined culture medium suitable for sustaining the growth of P. falciparum. 相似文献
207.
Anthropogenic stratospheric ozone depletion causes an increase in UVB radiation impinging on the earth's surface, which is a threat to plants not adapted to higher UVB irradiances. Investigations were carried out among tropical marine macrophytes, Turbinaria turbinata, Sargassum polyceratium var. ovatum, Padina sanctae-crucis, Lobophora variegate, Dictyota spec., Halimeda discoidea, Udotea flabellum, Thalassia testudinum and Syringodium filiforme collected from 0.3 to 26 m depths at the Belizean barrier reef, where ultraviolet radiation (UV)-irradiances are naturally high. Photoinhibition was induced under full solar, UV (UVA + UVB), and UVA only-depleted radiation conditions. Photosynthetic activity during high radiation stress and during recovery in reduced solar radiation was determined in vivo by measuring fluorescence changes using a PAM fluorometer device. Generally, UV caused an additional decrease of photosynthetic performance during high light stress which varies according to species, depth of growth and UV penetration at the site of collection; an observation in concordance with the conventional harmful UV-radiation effects on phototrophs. When solar radiation was reduced by 50%, significant photosynthetic recovery was observed. However, some shallow water species which are adapted to high UV were observed to recover less under treatment with depleted solar UVB radiation. Our result supports earlier reports that UVB causes not only negative effects on photosynthesis, but may also facilitate or induce recovery processes in aquatic macrophytes acclimated to high solar radiation which grow at the upper shoreline. Among the eulittoral macroalgae, e.g. Dictyota spec., P. sanctae-crucis, and H. discoidea and the seagrass T. testudinum, initiation of photosynthetic recovery processes in the presence of low irradiance of short UV-wavelengths may present an ecophysiological advantage compared to macrophytes which initiate photosynthetic recovery process during low light or in the absence of UV. 相似文献
208.
Abstract The fermentation of cellulose at 55°C by different associations of the 3 bacteria Clostridium thermocellum, Methanobacterium sp. and Methanosarcina MP, was studied. C. thermocellum alone produced acetate, lactate, ethanol, H2 and CO2 . The co-culture C. thermocellum-Methanobacterium sp. produced more acetate and less ethanol than the monoculture of Clostridium .
Methanosarcina MP used acetate only in the triculture including Methanobacterium sp. When methanol was added (5 mM) to the triculture, Methanosarcina MP had a shorter lag phase on acetate and degraded much more acetate. maximum methane production was 8.5 mmol CH4 /g cellulose degraded. 相似文献
Methanosarcina MP used acetate only in the triculture including Methanobacterium sp. When methanol was added (5 mM) to the triculture, Methanosarcina MP had a shorter lag phase on acetate and degraded much more acetate. maximum methane production was 8.5 mmol CH
209.
210.
Elizabeth Mendiaz Michael Mamounas John Moffett Ellis Englesberg 《In vitro cellular & developmental biology. Plant》1986,22(2):66-74
Summary Insulin, FeSO4, or transferrin are major requirements together with HEPES buffer and selenium for the growth of CHO-K1 (CCL 61) in a modified
F12 medium (M-F12). Insulin stimulates growth at 1 ng/ml to 10 μg/ml. In the defined medium minus insulin, CHO-K1 grows slowly
as elongated, elliptical cells in parallel arrays typical of normal diploid fibroblasts in contrast to round-to-cuboid cells
in loosely overlapping arrays in the presence of serum or insulin. During prolonged incubation in the absence of insulin the
cells gather up into a large spherical cluster of viable cells. Insulin “independent” mutants have been isolated whose growth
rate during exponential phase in the absence of insulin (48 h to 84 or 96 hrs) is 2.7 to 3.6 times that of the parental culture.
Insulin stimulates the growth of these variants only during the first 48 h and is inhibitory at 50 to 500 ng/ml during the
exponential phase. Insulin induction of the A system of amino acid transport occurs in about 8 h and requires both protein
and RNA synthesis.
This work was supported in part by National Science Foundation Grant PCM 7903242 and by the University of California. 相似文献