Arginine synthesis by hepatomas in vitro. I. The requirements for cell growth in medium containing ornithine in place of arginine and the isolation and characterization of variant hepatomas auxotrophic for arginine

1984 ◽  
Vol 68 (1) ◽  
pp. 285-303 ◽  
Author(s):  
S.J. Goss
Keyword(s):  
Cell Growth ◽  
The Other ◽  
Gene Products ◽  
Carbamoyl Phosphate Synthetase ◽  
Arginine Biosynthesis ◽  
Carbamoyl Phosphate ◽  
Isolation And Characterization ◽  
Ornithine Transcarbamoylase

Cell growth in ‘ornithine-medium’ requires the expression of two liver-specific genes, those for ornithine transcarbamoylase (OTC) and carbamoyl phosphate synthetase I (CPS-I). CPS-II appears unable to replace CPS-I in this system. The need for N-acetylglutamate (to activate CPS-I) can be met, at least in part, by providing it in the medium. The other gene products involved in arginine biosynthesis are probably all ubiquitous (i.e. not tissue-specific). In an attempt to study the factors responsible for the expression of liver-specific genes, variant hepatomas are isolated that have lost the ability to grow in ornithine-medium. Two classes of ‘orn-’ variants are identified: unstable variants that require dexamethasone for adequate CPS-I production, and ‘stable’ variants that have lost many liver-specific traits. Studies on one stable variant show that it can revert (though rarely), and that it regains its various liver-specific traits in a non-coordinate fashion.

Arginine synthesis by hepatomas in vitro. II. Isolation and characterization of Morris hepatoma variants unable to convert ornithine to arginine, and modulation of urea-cycle enzymes by dexamethasone and cyclic-AMP

1984 ◽  
Vol 68 (1) ◽  
pp. 305-319
Author(s):  
S.J. Goss
Keyword(s):  
Cyclic Amp ◽  
Liver Cells ◽  
Isolation And Characterization ◽  
Rat Liver Cells ◽  
Morris Hepatoma ◽  
Ornithine Transcarbamoylase ◽  
Cellular Incorporation

‘77orn’, a derivative of the Morris rat hepatoma 7777, stably expresses high levels of ornithine transcarbamoylase (OTC) and carbamoylphosphate synthetase I (CPS-I), and is able to grow indefinitely in ornithine-medium (medium with ornithine in place of arginine). Variants that have lost this ability are isolated from 77orn by a ‘suicide’ selective technique dependent on the cellular incorporation of [3H]ornithine. These variants, which have reduced levels of CPS-I, or of both CPS-I and OTC, are shown to have developed multiple hormonal requirements; their enzyme deficiencies can be reversed by use of an appropriately supplemented medium. In particular, CPS-I is inducible by dexamethasone and dibutyryl-cyclic-AMP in combination. Cholera toxin can be used instead of cyclic-AMP, but then butyrate is additionally required if the induction is to be maintained in the long term. The use of these agents in excess can depress OTC. Several other hepatomas, and alos explanted foetal rat liver cells, have similar requirements for CPS-I expression. It is argued that multiple hormonal requirements for CPS-I production are normal in liver cells in vitro, and that hormone-independent hepatomas should be regarded as abnormal. The implications of this for the somatic cell genetic investigation of differentiation are briefly discussed.

Characterization of cystathionine synthase as a selectable, liver-specific trait in rat hepatomas

1986 ◽  
Vol 82 (1) ◽  
pp. 309-320
Author(s):  
S.J. Goss
Keyword(s):  
Cell Growth ◽  
Serum Proteins ◽  
Selective Medium ◽  
Carbamoyl Phosphate ◽  
Cycle Enzyme ◽  
Wide Range ◽  
Specific Trait ◽  
Well Differentiated

Cell growth using homocysteine as a source of cysteine-sulphur requires two enzymes, cystathionine synthase (CS) and gamma-cystathionase (CT). The second of these enzymes, CT, is apparently present in most cell lines regardless of their tissues of origin, since most cells can grow in vitro in the absence of cystine if they are provided with cystathionine, the intermediate in the pathway. Likewise, homocysteine will support the growth of many human cells. However, of a wide range of rodent cells, only well-differentiated rat hepatoma cells were found to grow using homocysteine in place of cystine. It is shown that cell growth in homocysteine-medium correlates well with the presence in the cells of detectable levels of CS. Furthermore, in cells able to grow in homocysteine-medium, it is possible to demonstrate the homocysteine-dependent trans-sulphuration of serine to cysteine. Growth in homocysteine-medium is not dependent on the release of preformed cysteine from disulphide complexes with serum proteins. In cell hybrids, and in ‘dedifferentiated’ variants of rat hepatomas, CS, but not CT, is subject to extinction coordinately with well-characterized liver-specific traits. For rodent cells, homocysteine-medium thus acts as a selective medium requiring the expression of a single liver-specific trait, CS. In addition it is shown that, in certain hepatoma variants, CS is regulated co-ordinately with a urea-cycle enzyme (carbamoyl phosphate synthetase I) by glucocorticoids and cyclic-AMP. Cell death through cysteine starvation is briefly considered. The immediate cause of death is apparently an insufficient supply of reduced glutathione. Selenium and vitamin E assist cell growth when the supply of cysteine is limiting.

ISOLATION AND CHARACTERIZATION OF A PITUITARY PEPTIDASE SPECIFICALLY RELEASING, FROM GROWTH HORMONE, A PEPTIDE (SOMANTIN) WITH ANTAGONISTIC ACTIVITY TO INSULIN IN VITRO

1973 ◽  
Vol 59 (2) ◽  
pp. 261-274 ◽  
Author(s):  
C. J. DRIVER ◽  
J. McD. ARMSTRONG ◽  
J. BORNSTEIN ◽  
F. M. NG
Keyword(s):  
Molecular Weight ◽  
Growth Hormone ◽  
Antagonistic Activity ◽  
The Other ◽  
Limited Extent ◽  
Isolation And Characterization ◽  
Pituitary Glands

SUMMARY A peptidase has been isolated from ovine pituitary glands and has been purified. It specifically hydrolyses ovine growth hormone, releasing a peptide with somantin activity. It is proposed to call this peptidase somantin-releasing enzyme (SRE). It is a di-isopropylphosphorofluoridate-sensitive peptidase with a molecular weight of 23000 Daltons. It is optimally active near pH 8·0. It is of quite limited specificity, as it hydrolysed growth hormone to a limited extent only and did not hydrolyse most of the other proteins tested as substrates.

Isolation and Characterization of a Cyclic Hydroxamic Acid from a Pollen Extract, Which Inhibits Cancerous Cell Growth in Vitro

1995 ◽  
Vol 38 (4) ◽  
pp. 735-738 ◽  
Author(s):  
Xin Zhang ◽  
Fouad K. Habib ◽  
Margaret Ross ◽  
Ulrich Burger ◽  
Ari Lewenstein ◽  
...  
Keyword(s):  
Cell Growth ◽  
Hydroxamic Acid ◽  
Pollen Extract ◽  
Isolation And Characterization ◽  
Cancerous Cell ◽  
Cyclic Hydroxamic Acid

PENGEMBANGAN TEKNOLOGI SELEKSI IN VITRO BERULANG (REPEAT CYCLING–IN VITRO SELECTION) TOLERAN STRES KEKERINGAN UNTUK PERBAIKAN MUTU GENETIK DAN PRODUKSI TANAMAN KEDELAI BERMIKORIZA

2017 ◽  
Vol 1 (1) ◽  
pp. 74-84
Author(s):  
Ahmad Riduan ◽  
Rainiyati Rainiyati ◽  
Yulia Alia
Keyword(s):  
Arbuscular Mycorrhizae ◽  
In Vitro Selection ◽  
Soil Samples ◽  
Single Spore ◽  
Isolation And Characterization ◽  
Single Spore Culture ◽  
Spore Culture ◽  
Glomus Sp

Every plant rhizospheres in any ecosystem there are various living microorganisms including Arbuscular Mycorrhizae Fungi (AMF).  An isolation and characterization is required to investigate the species or type of the AMF. This research was aimed at studying the isolation and characterization of AMF sporulation in soybean rhizospheres in Jambi Province. The results of evaluation on soil samples before trapping showed that there are spores from three genus of AMF twelve types Glomus , two types Acaulospora and one type of Enthrophospora.  Following single spore culture in soybean rhizosphere, 5 spore types were obtained:  Glomus sp-1, Glomus sp-4, Glomus sp-7, Glomus sp-8 Glomus sp-10.

Isolation and characterization of phosphate solubilizing bacteria from the rhizospheric soil of Ponthenpuzha forest, Pathanamthitta (District), Kerala

2021 ◽  
Vol 16 (8) ◽  
pp. 110-117
Author(s):  
Kannan Abhirami ◽  
K. Jayakumar
Keyword(s):  
Bacterial Isolate ◽  
Phosphate Solubilizing Bacteria ◽  
Cymbopogon Citratus ◽  
16S Rrna Sequence ◽  
Isolation And Characterization ◽  
16S Rrna Sequence Analysis ◽  
Phosphate Solubilizing ◽  
Level Identification

Phosphorous is considered as a major parameter for crop yield. Its availability to plant is independent of its abundance. For the plants to utilize phosphorous, it is to be converted to absorbable form. Here, the part rendered by phosphate solubilizing bacteria is significant for it plays a crucial role in the formation of plant usable phosphate from organic forms. In the present work, an effort had been made to isolate and identify phosphate solubilising bacterial isolate from the rhizhospheric soils of various plants in Ponthenpuzha forest. One of the isolate from Cymbopogon citrates responded positively to Pikovskaya’s medium by producing a halo zone during in vitro culture. Colony features and 16S rRNA sequence analysis identified the isolate as Burkholderia sps. We have reported the presence of genus Burkholderia in the rhizospheric zone of Cymbopogon citratus. Further studies are warranted for species level identification of the isolate.

scholarly journals Isolation and characterization of arsenic resistant soil bacteria and their effects on germination of rice under arsenic contamination

2015 ◽  
Vol 2 (2) ◽  
pp. 229-237
Author(s):  
Istiaq Ahmed ◽  
Md Tofazzal Islam ◽  
Md Akhter Hossain Chowdhury ◽  
Md Kamruzzaman
Keyword(s):  
Contaminated Soils ◽  
Sodium Arsenite ◽  
Agar Plate ◽  
Rice Seedling ◽  
Resistant Bacteria ◽  
Gram Staining ◽  
Isolation And Characterization ◽  
Resistant Strains

This study was carried out to isolate, screen and characterize arsenic (As) resistant bacteria from As contaminated soils of Dumrakandi and Matlab under Faridpur and Chandpur districts and to evaluate their efficiency in reducing As toxicity against rice seedlings during germination. Thirteen strains were isolated from the soils which showed resistance to different levels of sodium arsenite (viz. 5, 10, 20 and 40 mM) in both agar plate and broth assay using BSMY I media. Among the isolates, BTL0011, BTL0012, BTL0015 and BTL0022 showed highest resistance to 40 mM sodium arsenite. Gram staining and KOH solubility test revealed that five strains were gram positive and rest eight was gram negative. They grew well in the liquid media at pH 5.5 to 8.5. In-vitro rice seedling bioassay with two superior isolates (BTL0011 and BTL0022) revealed that As resistant strains significantly enhanced seed germination of BRRI dhan29 and BRRI dhan47 at 60 ppm As. This study was laid out in CRD with three replications. The performance of BTL 0022 was superior to BTL0011. The overall results suggest that BTL0011 and BTL0022 can be used for bioremediation of As contaminated soils and to increase the germination and seedling growth of rice in As contaminated soils.Res. Agric., Livest. Fish.2(2): 229-237, August 2015

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