共查询到20条相似文献,搜索用时 46 毫秒
1.
ADAMTSs (A Disintegrin And Metalloproteinase with ThromboSpondin motifs) are secreted proteases dependent on Zn2+/Ca2+, involved in physiological and pathological processes and are part of the extracellular matrix (ECM). Here, we investigated if ADAMTS-1 is required for invasion and migration of cells and the possible mechanism involved. In order to test ADAMTS-1's role in ovarian cancer cells (CHO, NIH-OVCAR-3 and ES2) and NIH-3 T3 fibroblasts, we modified the levels of ADAMTS-1 and compared those to parental. Cells exposed to ADAMTS-1-enriched medium exhibited a decline in cell migration and invasion when compared to controls with or without a functional metalloproteinase domain. The opposite was observed in cells when ADAMTS-1 was deleted via the CRISPR/Cas9 approach. The decline in ADAMTS-1 levels enhanced the phosphorylated form of Src and FAK. We also evaluated the activities of cellular Rho GTPases from cell lysates using the GLISA® kit. The Cdc42-GTP signal was significantly increased in the CRISPR ADAMTS-1 ES-2 cells. By a Förster resonance energy transfer (FRET) biosensor for Cdc42 activity in ES-2 cells we demonstrated that Cdc42 activity was strongly polarized at the leading edge of migrating cells with ADAMTS-1 deletion, compared to the wild type cells. As conclusion, ADAMTS-1 inhibits proliferation, polarization and migration. 相似文献
2.
In the Azolla-Anabaena azollae symbiotic system, Anabaena akinetes get entrapped between the indusium and the apical cap of the megaspore apparatus during megasporocarp development, thus maintaining the continuity of the cyanobacterial association throughout the life cycle of the fern. The entrapped akinetes serve as the source of inoculum for infecting the new sporophyte when it is emerging from the megaspore apparatus. A procedure to generate Anabaena-free Azolla was developed by fertilizing the germinating megasporocarps in which the indusium along with the akinetes were removed by micromanipulation. This method has the advantage of not requiring drastic treatments of Azolla with antibiotics to eliminate the endosymbiotic cyanobacterial cells. Details of this new method and its usefulness in studies aimed at recombination of Azolla with Anabaena azollae are discussed.Abbreviations IRRI
International Rice Research Institute
- I–
IRRI medium devoid of combined nitrogen
- I+
IRRI medium containing combined nitrogen
- SDS
sodium dodecyl sulfate 相似文献
3.
Takio Susumu Akita Chikako Ngumi Victoria Wambui Takami Shinji 《Plant cell reports》1990,8(10):575-578
Suspension cultured cells of the liverwort, Reboulia hemisphaerica and of the moss, Barbula unguiculata were independently subcultured in the medium containing 2% glucose in the dark or in the light for more than one year, and the photosynthetic activities of the final cultures were determined. Throughout the culture period light-grown cells of both species contained high amount of chlorophyll (4 to 34 g mg–1 dry weight) and showed a high photosynthetic activity (10 to 84 mol O2 mg–1 chlorophyll h–1). Dark-grown cells of R. hemisphaerica showed the same level of chlorophyll content and photosynthetic O2 evolving activity as light-grown cells. Although chlorophyll content in dark-grown B. unguiculata cells was ten-fold lower than that in light-grown cells, the photosynthetic activity of these dark-grown cells was higher than that of light-grown cells based on chlorophyll content. 相似文献
4.
Treatment of the roots of 24–48 h old seedlings of the forage legumeLotus corniculatus with 1.0% Cellulase YC, and 0.1% Pectolyase Y-23 in 4.2% mannitol solution released protoplasts from the tips of root hairs within 30–40 sec of enzyme incubation. Roots from approximately 1000 seedlings yielded 1.7×105 protoplasts. Ten percent of protoplasts divided to form cell colonies when cultured at 1.0×105 ml–1 in droplets of KM8P medium with 0.6% Sea Plaque agarose. Colonies formed callus on UM agar medium; protoplast-derived tissues produced shoots on B5 medium containing 0.05 mg 1–1 of BAP. Regenerated plants were phenotypically and cytologically normal (2n=2x=24±2), and produced nitrogen fixing root nodules following inoculation withRhizobium. These results confirm the totipotency of protoplasts isolated from specialised epidermal cells of seedling roots ofLotus corniculatus. 相似文献
5.
Summary The influence of composition of media used for growth and delta-endotoxin production by B. thuringiensis var. kurstaki was studied with the idea of finding a cheap medium for attaining high yields of spore-crystal preparations. A new medium, based on malt sprouts is proposed. Data on growth and bioinsecticidal activity are given. A concentration of 2.1 × 109 spores.ml-1 was attained in a 48 h process. The spore-crystal preparations obtained present a LC50 of 2.18 × 108 spores.g-1 against larvae of Galleria mellonella. 相似文献
6.
Spheroplasts of Agrobacterium tumefaciens strains and E. coli were fused with protoplasts of Nicotiana tabacum. Fusion products were cultured in the presence of antibiotics to eliminate remaining bacterial spheroplasts. On hormone free medium, tobacco protoplasts treated with wild type Agrobacterium-strains formed colonies with an average frequency of 10–4. Opine synthesis was detected in the tissues. Some calli derived from protoplasts treated with A. tumefaciens C58C1pRi15834 formed typical hairy roots. Kanamycin resistant calli were obtained after fusion with A. tumefaciens containing pLGVTi23 neo (frequency=10–3). Fusion of E. coli spheroplasts containing a virulent pTiB6S3::RP4 co-integrate with tobacco protoplasts yielded two hormone independent growing calli producing octopine out of 105 microcalli.Abbreviations PEG
Polyethylene glycol
- PVA
Polyvinyl alcohol 相似文献
7.
The present experimentation compared the best nutrient medium, temperature, and growth hormones for callus induction and growth of various pine species from different seed sources with their effect on growth of Phytophthora cinnamomi. Callus tissues maintained on a modified Murashige and Skoog medium with 10–5M 2,4-D at 26°C in the dark optimized the expression of differential resistance when inoculated with hyphae of P. cinnamomi. High concentration of 2,4-D (5×10–5M) inhibited growth of P. cinnamomi.Abbreviations AL
loblolly pine-Alabama
- PL
South Carolina
- AS
shortleaf pine-Alabama
- CS
Georgia
- AV
Virginia pine-Alabama 相似文献
8.
Danielle-Julie Carrier Gregory Cosentino Ronald Neufeld Denis Rho Martin Weber Jean Archambault 《Plant cell reports》1990,8(11):635-638
Calli were obtained from Ginkgo biloba embryos grown on Murashige and Skoog (MS) medium. The G. biloba cells could grow on either MS or Gamborg B5 mineral salt medium supplemented with sucrose (3% and 2%, respectively) and naphthaleneacetic acid (NAA) and kinetin (K) in concentrations ranging from 0.1 to 2.0 mg·L–1. Best growth and maintenance of callus cultures were achieved using MS medium supplemented with 2 mg·L–1 NAA and 1 mg·L–1 K (N2K1MS). Light was required to maintain healthy growth of the callus tissue.In both MS and B5 based media, sucrose was hydrolyzed extracellularly before being taken up by Ginkgo cell suspension cultures. Specific growth rates of 0.13 d–1 and 0.08 d–1 were obtained in MS medium supplemented with 1 mg·L–1 NAA, 0.1 mg·L–1 K and 30 g·L–1 sucrose (N1K0.1MS) and B5 medium supplemented with the same growth regulator regime and 20 g·L–1 sucrose (N1K0.1B5) respectively. Complete phosphate and ammonium uptake was observed in 11 days when cultured in MS medium and 10 days and 4 days respectively when cultured in B5 medium. During the culture, G. biloba cells consumed only 64% and 29% of the nitrate content of N1K0.1MS and N1K0.1B5 media respectively. Maximum dry biomass concentrations were 13.4 g·L–1 and 7.9 g·L–1, and yields on carbohydrate were 0.39 and 0.45 in N1K0.1MS and N1K0.1B5 media respectively. The better performance of MS cultures came from the higher sucrose and nitrogen salts concentrations of this medium.Abbreviations B5
Gamborg mineral salt medium
- d.w.
Dry weight
- K
Kinetin
- MS
Murashige and Skoog mineral salt medium
- N or NAA
Naphthaleneacetic acid
- NiKjMS
i and j are the respective concentrations (mg·L–1) of NAA and K
- n
Number of experimental points
- r
Linear regression correlation coefficient 相似文献
9.
Summary
E.
coli cells harbouring plasmid pBR322 which confers ampicillin resistance were immobilized on cotton cloth. The resulting film was used as an inoculum in daily repeated batch culture in ampicillin-free medium. During two months, the film was able to produce cultures which, at the late log phase, showed little sensitivity to 10 mg/ml ampicillin. Thus such a bacterial film can effectively be used as an inoculum for the production of recombinant DNA products by means of pBR322 or its derivatives in the absence of ampicillin. 相似文献
10.
A. Ratner M.C. Wilson L. Srivastava G.T. Peake 《Prostaglandins & other lipid mediators》1974,5(2):165-171
The effect of prostaglandin E1 (PGE1) on rat anterior pituitary cyclic AMP accumulation and luteinizing hormone (LH) release was studied both in vivo and in vitro. Addition of PGE1 to incubation medium over a concentration range of 10-6 to 10-4 M produced a graded increase in pituitary cyclic AMP. At the lowest concentration (10-6 M) there was no significant increase in LH release, but proportional increments in LH release were seen with increasing concentrations of PGE1.Ten minutes after intravenous administration of 5 μg of PGE1 to adult male rats, pituitary cyclic AMP was substantially increased while serum LH levels were not changed. Administration of a higher dose of PGE1 (20 μg) produced a greater increase in pituitary cyclic AMP; and, at this dose serum LH was significantly increased. These results suggest that the PGE1 effect on LH release is mediated by the adenyl cyclase — cyclic AMP system. 相似文献
11.
An immobilization technique has been developed for a packed bed fermenter which is being considered as one stage of a process for the production of fuel-grade ethanol from sugar solutions. Relatively inexpensive beech wood chips have been successfully used as the support material and relatively high cell loadings of 188 mg DW cells/g DW support have been achieved for a test system of Saccharomyces cerevisiae cultures.No washout of adsorbed cells occurs below a superficial liquid velocity of 8.9 × 10-2 cm/s which can be increased to 9.7 × 10-2 cm/s by including up to 1% Hercofloc solution in the reactor medium during the immobilization procedure. The immobilization procedure is practically unaffected by pH and temperature in the range 3.5 to 5.0 and 22 °C to 37 °C respectively.Typical ethanol productivity of 21.8g/l·hr has been obtained with wood-chip-adsorbed cells, which compares well with optimal values of 18 to 32g/l·hr obtained using free-suspension cultures in stirred-tank fermenters with cell recycle. 相似文献
12.
Hypocotyl explants of 1 and 10 mm lengths were excised from 12-day-old in vitro-grown seedlings of Albizia richardiana. The larger pieces, after 40 days of culture, developed shoots along with green calli on B5 + BAP (10–7–10–5M), while the smaller segments produced only green calli on B5+BAP (10–7–10–4M) medium. Some of the green calli turned morphogenic and started producing somatic embryos with the 2nd sub-culture and shoots from 7th sub-culture onwards. Calli retained the morphogenic potential even after repeated sub-culturing for over two years. The number of embryos in an embryogenic culture varied from 2 to 20 per callus mass of 5–6.5 cm3. Sucrose at the 2% level in MS medium was optimal for embryogenesis while 4% was optimal for shoot bud differentiation. Higher levels of sucrose (6–10%) caused browning of green calli and also inhibited differentiation into embryos and shoot buds. By selective sub-culturing of 0.1 cm3 pieces of embryogenic calli on MS+10–5M BAP, 46% of the cultures produced somatic embryos. The latter germinated into plantlets on Knop's medium.Abbreviations BAP
6-benzylaminopurine
- B5
Gamborg et al., 1968 medium
- IAA
Indole-3-acetic acid
- MS
Murashige and Skoog's (1962) medium 相似文献
13.
Using defined media and controlled gaseous conditions in vitro nitrogenase activity, as monitored by acetylene reduction, was detected after 16 hours of derepression. Specific activity of nitrogenase increased progressively over a period of 100 hours. The method used here utilises rapidly agitated cultures of Rhizobium strain ANU289, incubated at 28°C at cell densities of ca. 1×109 cells ml–1. The optimal medium for rapid derepression contained basic physiological salts with 3 mM glutamate and 50 mM sodium succinate being the only carbon and nitrogen additives. The gas phase was kept constant by a continuous flow of an air-nitrogen mixture with oxygen being maintained at 0.2%. The described culture system provides the opportunity to observe the regulation of nitrogenase activity in a near-chemostat situation. 相似文献
14.
Summary A culture technique, based on the growth of a microorganism on inert porous particles (e. g. pozzolano) impregnated and continuously fed with substrate is applied to the growth and spore production ofPenicillium roqueforti. The composition and the feed rate of the medium can be controlled, and the biomass is directly estimated.P. roqueforti exhibits a diauxic growth on the medium containing sucrose and malt extract used, and 1.5 109 spores/g pozzolano may be obtained. 相似文献
15.
Cyclic AMP and citric acid accumulation by Aspergillus niger 总被引:3,自引:0,他引:3
Aspergillus niger accumulated citric acid in the medium under certain conditions. Cyclic AMP concentrations of the order of 10?6M and higher caused an increase in the rate of citrate synthesis. Adenosine, ATP, and cyclic GMP at 10?3M also stimulated, but were ineffective at 10?4M. 5′-AMP had no effect while 5′-GMP and guanosine inhibited slightly. ADP showed a 42% inhibition. Theophylline enhanced the cyclic AMP effect. It is proposed that citric acid accumulation by Aspergillus niger may result from abnormal cyclic AMP metabolism. 相似文献
16.
The amido hydrolase encoded by the T-DNA gene 2 catalyzes the conversion of indole-acetamide, -naphthalene acetamide, and other substrate analogues into the corresponding auxins. As a result, only gene 2-expressing protoplast-derived tobacco cells can grow in medium containing low concentrations (0.2–1 M) of -naphthalene acetamide as auxin precursor. However, in a mixture of SR1 and SR1, gene 2
+ protoplast-derived cells, cross-feeding occurs and consequently no positive selection for gene 2 is obtained. A 100-times higher concentration of -naphthalene acetamide (between 30 and 300 M) provides a negative selection scheme. Only the tobacco cells expressing gene 2 are sensitive to the high naphthalene acetamide concentration and cannot grow to colonies, while cells lacking the gene 2 product regenerate calli even in mixed gene 2
+ and gene 2
– cell populations. Thus, gene 2 might provide a unique biochemically defined marker to investigate mutations and gene inactivation. 相似文献
17.
G. A. King A. J. Daugulis P. Faulkner D. Bayly M. F. A. Goosen 《Biotechnology letters》1988,10(10):683-688
Summary Insect cells (Spodoptera Frugiperda), infected with a temperature-sensitive mutant (TS10) of theAutographa Californica nuclear polyhedrosis virus (AcNPV), were cultured in multiple membrane alginate-polylysine (PLL) microcapsules. It was possible to obtain intracapsular cell densities of 8× 107 cells/mL of capsules and virus concentrations of up to 109 IFU/mL of capsules. This was higher by a factor of 10 than that which could be achieved by conventional cell suspension culture. 相似文献
18.
Plant regeneration from protoplasts of embryogenic cell suspensions of Coffea arabica L. cv. caturra
Coffee plants were regenerated from protoplasts isolated from embryogenic cell suspension cultures derived from somatic embryos of Coffea arabica L. cv. caturra. Yields of viable protoplasts ranged from 1×105 to 6×105 protoplast/g fresh weight. Protoplast preparations usually contained no contaminating cells, and when present, the number of cells never exceeded 0.1% of the total. Plating efficiencies of protoplast ranged from 1 to 10%. Embryogenic protocolonies obtained after several subcultures in a medium supplemented with 0.5 mg/l each of benzylaminopurine, 2,4-dichlorophenoxyacetic acid and naphtaleneacetic acid, were transferred to a medium lacking plant growth regulators. Well differentiated embryos were formed in selected protocolonies that contained many embryos-like structures. Approximately 70% of the somatic embryos developed into green rooted plantlets which were succesfully transferred to vessels containing sterilized scoria. Plants grown for two months in scoria were finally transferred to greenhouse.Abbreviations B5
medium according to Gamborg et. al.(1968)
- BAP
6-benzylaminopurine
- 2,4-D
2,4-dichlorophenoxyacetic acid
- NAA
naphtaleneacetic acid 相似文献
19.
Summary A 1.7-kb cryptic plasmid was isolated fromZymomonas
anaerobia and used to construct a shuttle vector inserting useful parts of pUC9, pBR322, and pRK2501.Escherichia
coli was employed to clone the new plasmid designated pSR12. The 7.7-kb plasmid pSR12 reisolated from the host cells could transform competent cells ofZ.anaerobia at 2×10–7 frequency. This shuttle vector contains two antibiotic resistance markers, Kanr and Tetr, as well as restriction sites such as EcoRI, PstI, and XhoI, suitable for DNA recombinations. 相似文献
20.
Claude P. Champagne 《Biotechnology letters》1990,12(10):771-776
Summary Cells ofLactococcus
lactis orLactobacillus
helveticus were immobilized in calcium-alginate beads, added to raw milk, and incubated 48 h at 7°C. The addition of 2.7×107 immobilizedLc.lactis or 13×107 immobilizedLb.
helveticus cells per mL reduced the development of the psychrotrophic bacteria of raw milk by approximately 50%. The pH of the raw milk dropped 0.10 to 0.22 units under these conditions. Periodic agitation of the seeded raw milk increased the inhibitory activity of the immobilized lactic acid bacteria (LAB). Free LAB cells in the system were only of 0.5% of total LAB. The use of immobilized LAB to inhibit psychrotrophic bacteria might be extended to raw milks destined to the manufacture of non-fermented dairy products. 相似文献