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1.
Trisporic Acid Biosynthesis in Separate Plus and Minus Cultures of Blakeslea trispora: Identification by Mucor Assay of Two Mating-Type-Specific Components 总被引:1,自引:0,他引:1
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Richard P. Sutter Domenick A. Capage Thomas L. Harrison William A. Keen 《Journal of bacteriology》1973,114(3):1074-1082
Separate plus and minus cultures of Blakeslea trispora synthesize small amounts of trisporic acids under specific conditions. These amounts are expressed as a percentage of the trisporic acids (50 mg/liter of medium) synthesized by mixed plus-minus cultures in 5 days. Plus cultures, without additives from minus cultures, synthesize 0.1% trisporic acids. Plus cultures synthesize 0.4% trisporic acids when stimulated by M-factor, a mating-type-specific component synthesized by minus cultures. Minus cultures, without additives from plus cultures, do not synthesize even 0.0001% trisporic acids. Minus cultures synthesize 1% trisporic acids when stimulated by P-factor, a mating-type-specific component synthesized by plus cultures. Minus cultures synthesize M-factor when stimulated by pi, a component synthesized by plus cultures. We speculate that (i) minus cultures synthesize a component, mu, which stimulates P-factor synthesis in plus cultures, and (ii) both M-factor and P-factor are precursors of trisporic acids. 相似文献
2.
V A Filippov 《Antibiotiki》1976,21(12):1075-1078
Sensitivity of 84 cultures of L. fermenti, 43 cultures of L. brevis, 13 cultures of L. buchneri and 2 cultures of L. cellobiosus to the effect of 39 types of bacteriocins produced by various species of lactobacilli was studied with the method of delayed antagonism. All the cultures of L. brevis, L. buchneri and L. cellobiosus and 65.5 per cent of the cultures of L. fermenti were sensitive to one or more such bacteriocins. The cultures of L. Fermenti, L. brevis, L. buchneri and L. cellobiosus were sensitive respectively to 37, 19, 16 and 9 types of the bacteriocins out of 39 types tested. 相似文献
3.
Characterization of Primary and Secondary Cultures of Astrocytes Prepared from Mouse Cerebral Cortex
Skytt DM Madsen KK Pajęcka K Schousboe A Waagepetersen HS 《Neurochemical research》2010,35(12):2043-2052
Astrocyte cultures were prepared from cerebral cortex of new-born and 7-day-old mice and additionally, the cultures from new-born animals were passaged as secondary cultures. The cultures were characterized by immunostaining for the astrocyte markers glutamine synthetase (GS), glial fibrillary acidic protein, and the glutamate transporters EAAT1 and EAAT2. The cultures prepared from 7-day-old animals were additionally characterized metabolically using (13)C-labeled glucose and glutamate as well as (15)N-labeled glutamate as substrates. All types of cultures exhibited pronounced immunostaining of the astrocyte marker proteins. The metabolic pattern of the cultures from 7-day-old animals of the labeled substrates was comparable to that seen previously in astrocyte cultures prepared from new-born mouse brain showing pronounced glycolytic and oxidative metabolism of glucose. Glutamate was metabolized both via the GS pathway and oxidatively via the tricarboxylic acid cycle as expected. Additionally, glutamate underwent pronounced transamination to aspartate and alanine and the intracellular pools of alanine and pyruvate exhibited compartmentation. Altogether the results show that cultures prepared from cerebral cortex of 7-day-old mice have metabolic and functional properties indistinguishable from those of classical astrocyte cultures prepared from neocortex of new-born animals. This provides flexibility with regard to preparation and use of these cultures for a variety of purposes. 相似文献
4.
D E Brenneman E A Neale G A Foster S W d'Autremont G L Westbrook 《The Journal of cell biology》1987,104(6):1603-1610
The developmental regulation of neuronal survival by vasoactive intestinal peptide (VIP) was investigated in dissociated spinal cord-dorsal root ganglion (SC-DRG) cultures. Previous studies demonstrated that VIP increased neuronal survival in SC-DRG cultures when synaptic transmission was blocked with tetrodotoxin (TTX). This effect was further investigated to determine if VIP acted directly on neurons or via nonneuronal cells. For these studies, SC-DRG cells were cultured under conditions designed to provide preparations enriched for a particular cell type: astrocyte-enriched background cell (BG) cultures, meningeal fibroblast cultures, standard mixed neuron-nonneuron (STD) cultures, and neuron-enriched (N) cultures. Addition of 0.1 nM VIP to TTX-treated STD cultures for 5 d prevented the TTX-mediated death and the death that occurred naturally during development in culture, whereas the same treatment on N cultures did not prevent neuronal cell death. Conditioned medium from VIP-stimulated BG cultures prevented neuronal cell death when added to the medium (10% of total volume) of N cultures treated with TTX. The same amount of conditioned medium from BG cultures that were not treated with VIP had no protective action on N cultures. Conditioned medium from N or meningeal fibroblast cultures, either with or without VIP treatment, did not prevent TTX-mediated cell death in N test cultures. These data indicate that VIP increases the availability of neurotrophic survival-promoting substances derived from nonneuronal cultures, the most likely source being astroglial cells. This study suggests that VIP has a role in mediating a neuron-glia-neuron interaction that influences the trophic regulation of neuronal survival. 相似文献
5.
In vitro growth and chromosome constitution of placental cells. I. Spontaneous and elective abortions 总被引:3,自引:0,他引:3
Placental cultures from chromosomally normal spontaneous abortions, as well as placental and fetal cultures from chromosomally normal elective abortions, were established, and the growth and cytogenetic constitution of the cultures were compared. Fetal cultures grew well and remained chromosomally stable over the entire 100-day period of observation. In contrast, placental cultures were relatively short-lived, many becoming senescent and dying within the time of observation. This was particularly marked in cultures established from spontaneous abortions. Five of the 18 cultures established from spontaneous abortions, but only 1 of the 24 cultures from elective abortions, developed chromosomally abnormal clones. The emergence of such clones was unrelated to the senescence of the cultures. 相似文献
6.
Effect of nutrient variations on growth and brefeldin A formation inCurvularia lunata 总被引:1,自引:1,他引:0
C. T. Sam 《Folia microbiologica》1977,22(1):43-46
The highest level of secreted brefeldin A was present in glucose-grown cultures, intermediate levels in glucose-fructose,
and xylose cultures and low levels in fructose- and galaotose-grown cultures ofCurvularia lunata. The biomass decreased from glucose, fructose, xylose, glucose-fructose to galactose cultures. Brefeldin A levels and mycelial
yields were low in citrate-, gluconate-, and succinate-grown cultures. Inorganic phosphate-limited cultures supported a high
level of brefeldin A. Intermediate levels were present in trace elements-, and inorganic phosphate-trace elements-limited
cultures. 相似文献
7.
Stefan Peter Andy M. Scutt Phillip C. Wright Catherine A. Biggs 《Biotechnology letters》2013,35(3):463-469
Bone marrow-derived mesenchymal stem cells (BMD-MSCs) are of great interest for tissue engineering, but require expansion before they can be used for therapeutic applications. We compared three different culture techniques for their potential for large scale expansion of rat BMD-MSCs, i.e. monolayer cultures, stirred suspension cultures and pour-off cultures, and found that pour-off cultures supported the biggest expansion in BMD-MSCs as measured by the fibroblastic-colony forming unit assay (CFU-f). BMD-MSCs expanded in stirred suspension cultures stopped proliferating altogether and, although monolayer cultures allowed for expansion of BMD-MSCs, they favoured a differentiated phenotype over uncommitted MSCs. Only BMD-MSCs expanded in pour-off cultures were able to differentiate into both osteoblastic and adipocytic lineages and maintain CFU-f numbers. These data suggest that pour-off cultures are a viable method of BMD-MSC expansion. 相似文献
8.
N. Savion I. Vlodavsky G. Greenburg D. Gospodarowicz 《Journal of cellular physiology》1982,110(2):129-141
Confluent cultures of adult bovine aortic endothelial (ABAE), correal endothelial (BCE), and fetal bovine heart endothelial (FBHE) cells form a monolayer of highly flattened, closely apposed, and nonoverlapping cells. In ABAE and BCE cultures, this is associated with a 50-fold decrease in the rate of DNA synthesis and correlates with a 14-fold decrease in protein synthesis. In contrast, in confluent FBHE cultures only partial decreases in the rates of DNA synthesis (6-fold) and protein synthesis (3-fold) are observed. FBHE cells therefore fulfill the morphological, but not the biochemical, criteria for confluent cultured endothelial cell monolayers. The appearance of the cytoskeletal elements actin, tubulin, and vimentin in sparse and confluent cultures of endothelial cells has been analyzed by two-dimensional gel electrophoresis and immunofluorescence. Sparse versus confluent ABAE, FBHE, and BCE cultures showed no changes in their relative rates of synthesis or cellular content of tubulin. Actin behaved similarly to tubulin in FBHE and BCE cultures, while in ABAE cultures a small increase (3-fold) in its relative rate of synthesis was observed in confluent versus sparse cultures. BCE cultures showed no change in the rate of synthesis of vimentin, but the cellular content of vimentin was markedly increased when cultures reached confluence. When the distribution of vimentin in both sparse and confluent BCE cultures was analyzed by immunofluorescence, in both cases it appeared distributed throughout the cytoplasm as thin fibers and bundles of fibers. In confluent ABAE cultures, both the relative amount and biosynthetic rate of vimentin increased by 15-fold. This increase in the intracellular accumulation of vimentin correlated with its immunofluorescent distribution within the cells. While in sparse cultures, vimentin appeared to be distributed as thin fibers, in confluent cultures thick curl-like fibrous bundles could be seen distributed throughout the cytoplasm and organized in a perinuclear ring. In contrast, in FBHE cultures no significant changes in the distribution and organization of rate of synthesis of vimentin were observed. 相似文献
9.
A more than 99% reduction in infectivity of cultures infected with subacute sclerosing panencephalitis (SSPE) virus was obtained by treating the cultures with liposomes containing fragment A of diphtheria toxin. In the mixed cultures of human embryonic lung (HEL) cells and SSPE virus-infected HEL cells (SSPE cells), SSPE virus in SSPE cells invaded the surrounding HEL cells successively, forming syncytial giant cells to destroy the whole cultures. By adding liposomes containing fragment A of diphtheria toxin to the mixed cultures, we were successful in killing the SSPE cells selectively and as the result of elimination of SSPE cells from the cultures, the cultures appeared to be cured by uninfected HEL cell growth. 相似文献
10.
The effect of light on alkaloid accumulation in a range of cellcultures of tobacco was determined. Cell suspension culturesof Nicoriana rabacwn L. cv. Wisconsin-38 with differing degreesof photosynthetic activity, callus cultures of N. glauca Graham,root cultures of N. rustica L. and shoot cultures of N. tabacumwere used. The alkaloid content of green illuminated cultureswas greatly reduced compared with non-green cultures grown inthe dark, but decreased accumulation did not correlate withincreasing photosynthetic activity. The accumulation of allof the major alkaloids was affected, regardless of the speciesof tobacco used. Transfer of N. glauca callus from the darkinto the light caused a decrease in alkaloid accumulation, whilemoving cultures from the light into the dark resulted in anincrease in alkaloid content. In root cultures light causeda reduction in growth, which affected alkaloid synthesis. Inshoot cultures there were only traces of alkaloid detectable,regardless of whether or not cultures were illuminated. Lightappeared to cause a non-photosynthetic suppression of alkaloidaccumulation in visibly undifferentiated cultures, and thiseffect was modified in visibly differentiated cultures. Key words: Nicoriana spp, tobacco, alkaloid accumulation, cell culture 相似文献
11.
Armin R. Gemmrich 《Plant cell reports》1982,1(6):233-235
The changes of lipid composition were determined in callus cultures from Ricinus communis endosperm upon transfer from darkness into light. Culture in light induced chlorophyll synthesis and formation of differentiated chloroplasts. In light-grown cultures the major lipid classes were phospho- and glycolipids, dark-grown cultures were rich in triacylglycerol. The major fatty acids were linolenic acid and palmitic acid in both cultures. In the green cultures linolenic acid was predominantly esterified in glycolipids whereas in the dark-grown cultures this fatty acid was the major component of phospholipids. Ricinoleic acid was not found.Abbreviations PC
phosphatidylcholine
- PE
phosphatidylethanolamine
- MGD
monogalactosyldigylceride
- DGD
digalactosyldiglyceride
- SE
steryl esters
- NL
neutral lipids 相似文献
12.
Sulfated proteoglycan synthesis by confluent cultures of rabbit costal chondrocytes grown in the presence of fibroblast growth factor 总被引:13,自引:2,他引:11
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We examined the effect of fibroblast growth factor (FGF) on proteoglycan synthesis by rabbit costal chondrocyte cultures maintained on plastic tissue culture dishes. Low density rabbit costal chondrocyte cultures grown in the absence of FGF gave rise at confluency to a heterogeneous cell population composed of fibroblastic cells and poorly differentiated chondrocytes. When similar cultures were grown in the presence of FGF, the confluent cultures organized into a homogenous cartilage-like tissue composed of rounded cells surrounded by a refractile matrix. The cell ultrastructure and that of the pericellular matrix were similar to those seen in vivo. The expression of the cartilage phenotype in confluent chondrocyte cultures grown from the sparse stage in the presence vs. absence of FGF was reflected by a fivefold increase in the rate of incorporation of [35S]sulfate into proteoglycans. These FGF effects were only observed when FGF was present during the cell logarithmic growth phase, but not when it was added after chondrocyte cultures became confluent. High molecular weight, chondroitin sulfate proteoglycans synthesized by confluent chondrocyte cultures grown in the presence of FGF were slightly larger in size than that produced by confluent cultures grown in the absence of FGF. The major sulfated glycosaminoglycans associated with low molecular weight proteoglycan in FGF-exposed cultures were chondroitin sulfate, while in cultures not exposed to FGF they were chondroitin sulfate and dermatan sulfate. Regardless of whether or not cells were grown in the presence or absence of FGF, the 6S/4S disaccharide ratio of chondroitin sulfate chains associated with high and low molecular weight proteoglycans synthesized by confluent cultures was the same. These results provide evidence that when low density chondrocyte cultures maintained on plastic tissue culture dishes are grown in the presence of FGF, it results in a stimulation of the expression and stabilization of the chondrocyte phenotype once cultures become confluent. 相似文献
13.
Plant callus cultures have the potential to advance phytoremediation science by allowing study of cellular phytometabolism in absence of sorption, translocation, microbial degradation, and other phytoremediation processes; however, studies demonstrating the applicability of results from callus cultures to whole plants are limited. The aim of this study was to evaluate the feasability and applicability of using callus cultures to study phytometabolism. This aim was accomplished through evaluation of induction and growth of Lemnaceae callus cultures and comparison of phytometabolism in callus cultures and whole plants. Four out of eight published methods for callus culture of Lemnaceae successfully induced callus cultures that exhibited doubling times of 1.7 to 23 wks. Callus cultures and whole plants of Landoltia punctata and Lemna minor metabolized 3-trifluoromethylphenol (3-TFMP) through conjugation with glucopyranoside, malonyl-glucopyranoside, and glucopyranosyl-apiofuranoside. However, concentrations of metabolites were approximately 10 times less in callus cultures than in plants. While results demonstrated applicability of callus cultures results to whole plants, the low success rate of callus induction procedures, length of time required to produce substantial callus mass, and the low accumulation of metabolites in callus cultures may limit the feasibility of callus cultures for assessing phytometabolism. 相似文献
14.
Effect of ethanol on activity of the plasma-membrane ATPase in, and accumulation of glycine by, Saccharomyces cerevisiae 总被引:10,自引:0,他引:10
The pH optimum of the ATPase activity in plasma membranes from Saccharomyces cerevisiae NCYC 431 from 8 h cultures was around 6.5 and that in membranes from organisms from 16 h cultures near 6.0. The Km[ATP] of the enzyme was virtually unaffected by the age of the culture from which organisms were harvested, although the Vmax of the enzyme in membranes from organisms from 8 h cultures was higher than that for organisms from 16 h cultures. Ethanol non-competitively inhibited ATPase activity in membranes, although the inhibition constant for the enzyme from organisms from 8 h cultures was lower than that from organisms from 16 h cultures. Glycine accumulation by the general amino acid permease was non-competitively inhibited by ethanol. Inhibition constants were virtually the same for glycine uptake by deenergized organisms from 8 h and 16 h cultures, but under energized conditions the value was greater for organisms from 16 h rather than 8 h cultures. The data indicate that inhibition of plasma-membrane ATPase activity by ethanol could account, at least in part, for inhibition of glycine accumulation by ethanol. 相似文献
15.
Susceptibility to 11 antibiotics was determined for 63 cultures of Staphylococcus aureus and 63 cultures of Staphylococcus epidermidis obtained at random from the clinical laboratory. The incidence of resistance to nine of these antibiotics was greater for S. epidermidis than for S. aureus. Studies of the minimal inhibitory concentration of these cultures to clindamycin showed that 61 cultures of S. aureus were susceptible whereas only 46 cultures of S. epidermidis were susceptible to this antibiotic. Although cultures of S. aureus were more active in the production of seven virulence factors, some cultures of S. epidermidis produced virulence factors. By successive cultivation in increasing concentrations of clindamycin, resistant variants were obtained for 10 cultures of S. aureus and 3 cultures of S. epidermidis. The presence of subinhibitory concentrations of clindamycin inhibited the production of some virulence factors by the resistant variants. In view of the greater resistance of S. epidermidis to antibiotics and its ability to produce virulence factors, its isolation in the clinical laboratory should not be regarded lightly. 相似文献
16.
Detection of mycoplasma contamination in cell cultures by a mycoplasma group-specific PCR. 总被引:6,自引:3,他引:3
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F J van Kuppeveld K E Johansson J M Galama J Kissing G Blske J T van der Logt W J Melchers 《Applied microbiology》1994,60(1):149-152
The suitability of a 16S rRNA-based mycoplasma group-specific PCR for the detection of mycoplasma contamination in cell cultures was investigated. A total of 104 cell cultures were tested by using microbiological culture, DNA fluorochrome staining, DNA-rRNA hybridization, and PCR techniques. A comparison of the results obtained with these techniques revealed agreement for 95 cell cultures. Discrepant results, which were interpreted as false negative or false positive on the basis of a comparison with the results obtained with other methods, were observed with nine cell cultures. The microbiological culture technique produced false-negative results for four cell cultures. The hybridization technique produced false-negative results for two cell cultures, and for one of these cell cultures the DNA staining technique also produced a false-negative result. The PCR may have produced false-positive results for one cell culture. Ambiguous results were obtained with the remaining two cell cultures. Furthermore, the presence of contaminating bacteria interfered with the interpretation of the DNA staining results for 16 cell cultures. For the same reason the hybridization signals of nine cell cultures could not be interpreted. Our results demonstrate the drawbacks of each of the detection methods and the suitability of the PCR for the detection of mycoplasmas in cell cultures. 相似文献
17.
Resistance of Salmonellae Isolated in 1959 and 1960 to Tetracyclines and Chloramphenicol 总被引:2,自引:0,他引:2
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The resistance of cultures of Salmonella typhimurium to tetracyclines and chloramphenicol has been examined periodically. Although none of 200 cultures isolated prior to 1948 was resistant to the antibiotics, 5% of 100 cultures from man and 9% of 100 cultures from fowls which were isolated in 1956 and 1957 were resistant to tetracyclines. Among 158 cultures isolated from man and 100 cultures isolated from fowls in 1959 and 1960, 13.9 and 29%, respectively, were resistant to tetracyclines. In the last series, cultures resistant to chloramphenicol were found for the first time. Among 150 cultures of other Salmonella serotypes from man and 137 similar cultures isolated from fowls in 1959 and 1960, 5.3 and 8%, respectively, were found resistant to tetracyclines. There is no obvious explanation for the higher percentage of resistant strains occurring in S. typhimurium than in other serotypes. 相似文献
18.
Comparison of Macroscopic, Microscopic, and Radiometric Examinations of Clinical Blood Cultures in Hypertonic Media 总被引:14,自引:0,他引:14
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Richard Rosner 《Applied microbiology》1974,28(4):644-646
Clinical blood cultures were collected in the Bactec 8A flask (Johnston Laboratories, Cockeysville, Md.) and examined macrosopically, microscopically, and radiometrically in an effort to determine which approach produced the fastest detection time. Of 360 blood cultures found to contain organisms by subculture, 334 were first detected by Bactec, 98 by macroscopic examination, and 68 by microscopic examination. Examination times were at 4, 8, 16, 24, 36, and 48 h after collection of the specimen. Sixteen hours after specimen collection, microscopic examination had detected 31 positive cultures, macroscopic examination had detected two positive cultures, and Bactec had detected 160 positive cultures. By the end of the first 24 h of incubation, Bactec had detected 313 (93%) of those cultures eventually found to be positive. Although Bactec produced the fastest detection time in an overwhelming majority of the cultures, it failed to detect three of three Candida spp. cultures, three of five Bacteroides spp. cultures, and six of 32 Enterococcus spp. cultures during the first 48 h of incubation. 相似文献
19.
Rani Roy Valery Kudryashov Stephen B. Doty Itzhak Binderman Adele L. Boskey 《Differentiation; research in biological diversity》2010,79(4-5):211-217
The murine mesenchymal cell line, C3H10T1/2 in micromass culture undergoes chondrogenic differentiation with the addition of BMP-2. This study compares the use of BMP-2 vs. insulin, transferrin, and sodium selenite (ITS) to create a chondrogenic micromass cell culture system that models cartilage calcification in the presence of 4 mM inorganic phosphate. BMP-2 treated cultures showed more intense alcian blue staining for proteoglycans than ITS treated cultures at early time points. Both ITS and BMP-2 treated cultures showed similar mineral deposition in cultures treated with 4 mM phosphate via von Kossa staining, however FTIR spectroscopy of cultures showed different matrix properties. ITS treated cultures produced matrix that more closely resembled mouse calcified cartilage by FTIR analysis. 45Ca uptake curves showed delayed onset of mineralization in cultures treated with BMP-2, however they had an increased rate of mineralization (initial slope of 45Ca uptake curve) when compared to the cultures treated with ITS. Immunohistochemistry showed the presence of both collagens type I and type II in BMP-2 and ITS treated control (1 mM inorganic phosphate) and mineralizing cultures. BMP-2 treated mineralizing cultures displayed more intense staining for collagen type II than all other cultures. Collagen type X staining was detected at Day 9 only in mineralizing cultures treated with ITS. Western blotting of Day 9 cultures confirmed the presence of collagen type X in the mineralizing ITS cultures, and also showed very small amounts of collagen type X in BMP-2 treated cultures and control ITS cultures. By Day 16 all cultures stained positive for collagen type X. These data suggest that BMP-2 induces a more chondrogenic phenotype, while ITS treatment favors maturation and hypertrophy of the chondrocytes in the murine micromass cultures. 相似文献
20.
In a survey of dental health status of ancient Southern Peru, 101 skeletal remains were studied from five cultures: Paracas, Nazca, Tiahuanaco, Ica, and Inca. The Paracas and Ica cultures exhibited more missing antemortem teeth per mandible than the other cultures. Frequency of missing one or more third molars was less than expected and not as high as reported in peoples of Mongoloid heritage. The Paracas, Ica and Nazca, "coastal" cultures had a higher caries incidence than the "inland" cultures. Whether this relates to some difference in diet or water supply remains unresolved and warrants further investigation. Moderate attrition was noted in all the Precolumbian cultures but pulpal involvement was not observed. Osteitis, noted in all the cultures, was more pronounced in the Nazca, Paracas and Ica cultures. There appeared to be a direct relationship between caries involvement and the number of missing antemortem teeth to osteitis. Calculus was heavier in the Paracas and Ica cultures. In addition, the Paracas culture exhibited a dark brown stain on the teeth which may imply some difference between the cultures in either the food, water or social habits. 相似文献