Biochemical Evidence for Formate Transfer in Syntrophic Propionate-Oxidizing Cocultures of Syntrophobacter fumaroxidans and Methanospirillum hungatei

ABSTRACT The hydrogenase and formate dehydrogenase levels in Syntrophobacter fumaroxidans and Methanospirillum hungatei were studied in syntrophic propionate-oxidizing cultures and compared to the levels in axenic cultures of both organisms. Cells grown syntrophically were separated from each other by Percoll gradient centrifugation. In S. fumaroxidans both formate dehydrogenase and hydrogenase levels were highest in cells which were grown syntrophically, while the formate-H2 lyase activities were comparable under the conditions tested. In M. hungatei the formate dehydrogenase and formate-H2 lyase levels were highest in cells grown syntrophically, while the hydrogenase levels in syntrophically grown cells were comparable to those in cells grown on formate. Reconstituted syntrophic cultures from axenic cultures immediately resumed syntrophic growth, and the calculated growth rates of these cultures were highest for cells which were inoculated from the axenic S. fumaroxidans cultures that exhibited the highest formate dehydrogenase activities. The results suggest that formate is the preferred electron carrier in syntrophic propionate-oxidizing cocultures of S. fumaroxidans and M. hungatei.

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Functional heterogeneity with respect to oestrogen treatment in prolactin cell subpopulations separated by Percoll gradient centrifugation

Journal of Endocrinology ◽

10.1677/joe.0.1410251 ◽

1994 ◽

Vol 141 (2) ◽

pp. 251-258 ◽

Cited By ~ 7

Author(s):

B Velkeniers ◽

M Kazemzadeh ◽

L Vanhaelst ◽

E L Hooghe-Peters

Keyword(s):

Gradient Centrifugation ◽

High Density ◽

Female Rats ◽

Cell Subpopulation ◽

Percoll Gradient ◽

Prolactin Cell ◽

Prolactin Gene ◽

Prolactin Mrna

Abstract The effects of oestradiol on prolactin gene expression were studied by quantitative in situ hybridization histochemistry in different prolactin pituitary cell (sub)populations, which had been obtained by separation on a discontinuous Percoll gradient. When cells were incubated in vitro in the presence of oestradiol (10−8 m) for a period of 4, 24, 48 and 72 h, there was an increase in the amount of prolactin mRNA, from 24 h on, only in high-density prolactin cells and lactotrophs of the total cell suspension. In contrast, the amount of prolactin mRNA in lactotrophs of low density did not change upon treatment with oestradiol. Pharmacological treatment with 50 μg oestradiol/day (s.c.) of random cycling female rats in vivo for 14 days increased the total number of prolactin gene-expressing cells and more lactotrophs were recovered at high density after Percoll gradient centrifugation. These results suggest a preferential stimulatory effect of oestradiol on prolactin gene transcription on a subpopulation of lactotrophs. Changes observed in prolactin cell layers after oestradiol treatment in vivo may represent a preferential effect in situ on a particular mammotroph cell subpopulation. Journal of Endocrinology (1994) 141, 251–258

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Sperm morphology and IVF pregnancy rate: comparison between Percoll gradient centrifugation and swim-up procedures

Human Reproduction ◽

10.1093/oxfordjournals.humrep.a137383 ◽

1991 ◽

Vol 6 (4) ◽

pp. 581-588 ◽

Cited By ~ 74

Author(s):

P. Van Der Zwalmen ◽

G. Bertin-Segal ◽

L. Geerts ◽

C. Debauche ◽

R. Schoysman

Keyword(s):

Pregnancy Rate ◽

Sperm Morphology ◽

Gradient Centrifugation ◽

Percoll Gradient ◽

Rate Comparison

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ELECTRON MICROSCOPIC EVIDENCE FOR PURIFICATION OF COCONUT ROOT (WILT) DISEASE PHYTOPLASMA

CORD ◽

10.37833/cord.v18i01.353 ◽

2002 ◽

Vol 18 (01) ◽

pp. 34

Author(s):

M. Mayilvaganan ◽

J. J. Solomon

Keyword(s):

Plant Material ◽

Gradient Centrifugation ◽

Spherical Shape ◽

Electron Microscopic Examination ◽

Wilt Disease ◽

Diseased Plant ◽

Percoll Gradient ◽

Electron Microscopic ◽

Centrifugation Method ◽

Discontinuous Percoll Gradient

Root (wilt) disease phytoplasma was purified from diseased coconut tissues using discontinuous Percoll gradient centrifugation method. Crude sap prepared from coconut was layered on a discontinuous Percoll gradient of 15, 30, 50 and 60%(v/v). After centrifugation at 20,000 g for 30 min, the turbid fraction formed on the top of 30% gradient in the diseased plant material was recovered, processed and fixed for electron microscopy. Electron microscopic examination of sections prepared from purified preparation of diseased plant material showed typical cells of root (wilt) phytoplasma with heterogeneous sizes and more or less spherical shape that are similar to those found in sieve elements of diseased tissues and salivary glands of infective (viruliforms) insect vectors. These purified phytoplasma bodies showed trilaminar membrane with internal materials of ribosome granules and DNA fibrils. However, the yield in terms of number of cells was fewer and in addition to intact bodies, free membranes and empty bodies lacking internal contents also were observed.

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Separation of Isospora (Toxoplasma) gondii cysts and cystozoites from mouse brain tissue by continuous density - gradient centrifugation

Parasitology ◽

10.1017/s0031182000050071 ◽

1981 ◽

Vol 83 (1) ◽

pp. 103-108 ◽

Cited By ~ 70

Author(s):

A. W. C. A. Cornelissen ◽

J. P. Overdulve ◽

J. M. Hoenderboom

Keyword(s):

Toxoplasma Gondii ◽

Brain Tissue ◽

Density Gradient ◽

Infected Mouse ◽

Mouse Brain ◽

Density Gradient Centrifugation ◽

Gradient Centrifugation ◽

Percoll Gradient ◽

Isolation And Purification ◽

Reproducible Method

SUMMARYA simple, quick and reproducible method consisting of density-gradient centrifugation of homogenized infected mouse brain tissue on Percoll is described for the isolation and purification of cysts of Isospora (Toxoplasma) gondii. A 100% recovery of cysts, with 74·2% in a single fraction with a specific gravity of 1·056, was obtained by overlaying homogenates of infected mouse brains on a pre-formed Percoll gradient and centrifugation at low g forces. With this procedure recovery was independent of the age of the cysts. Titration of purified cystozoites showed there to be no loss of infectivity.

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Formate Dehydrogenase Activity in Cells and Outer Membrane Blebs of Desulfovibrio gigas

Anaerobe ◽

10.1006/anae.1995.1016 ◽

1995 ◽

Vol 1 (3) ◽

pp. 175-182 ◽

Cited By ~ 3

Author(s):

Tina S. Haynes ◽

Dwight J. Klemm ◽

Joseph J. Ruocco ◽

Larry L. Barton

Keyword(s):

Outer Membrane ◽

Dehydrogenase Activity ◽

Formate Dehydrogenase ◽

Desulfovibrio Gigas ◽

Membrane Blebs ◽

In Cells

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Fertilizability and structural properties of boar spermatozoa prepared by Percoll gradient centrifugation

Reproduction ◽

10.1530/jrf.0.1000477 ◽

1994 ◽

Vol 100 (2) ◽

pp. 477-483 ◽

Cited By ~ 30

Author(s):

S. A. Grant ◽

S. E. Long ◽

T. J. Parkinson

Keyword(s):

Structural Properties ◽

Gradient Centrifugation ◽

Percoll Gradient ◽

Boar Spermatozoa

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Meristic Analyses of Atlantic Mackerel, Scomber scombrus, from the North American Coastal Populations

Journal of the Fisheries Research Board of Canada ◽

10.1139/f69-248 ◽

1969 ◽

Vol 26 (9) ◽

pp. 2537-2540 ◽

Cited By ~ 2

Author(s):

K. T. MacKay ◽

E. T. Garside

Keyword(s):

Atlantic Ocean ◽

Growth Rates ◽

Biochemical Evidence ◽

Atlantic Mackerel ◽

Scomber Scombrus ◽

Dorsal Fin ◽

The North ◽

Breeding Populations ◽

Fin Rays ◽

Genetic Continuity

Mean counts of vertebrae, of anal and soft dorsal fin rays, and of peduncular finlets were identical in samples of Atlantic mackerel, Scomber scombrus, from the northern and southern breeding populations in the northwest Atlantic Ocean. This information, together with growth rates and biochemical evidence from the literature, suggests that although the populations occupy separate spawning regions there is sufficient exchange of individuals at other seasons to maintain considerable genetic continuity.

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A comparison of methods for preparing enriched populations of bovine spermatogonia

Reproduction Fertility and Development ◽

10.1071/rd08129 ◽

2009 ◽

Vol 21 (3) ◽

pp. 393 ◽

Cited By ~ 41

Author(s):

Muren Herrid ◽

Rhonda J. Davey ◽

Keryn Hutton ◽

Ian G. Colditz ◽

Jonathan R. Hill

Keyword(s):

Cell Sorting ◽

Gradient Centrifugation ◽

Fold Increase ◽

Type A ◽

Datura Stramonium ◽

Percoll Gradient ◽

Isolated Cells ◽

Antibody Staining ◽

Type A Spermatogonia

The objective of the present study was to identify an efficient and practical enrichment method for bovine type A spermatogonia. Four different enrichment methods were compared: differential plating on laminin- or Datura stramonium agglutinin (DSA)-coated flasks, percoll-gradient isolation, magnetic-activated cell sorting (MACS) and fluorescence-activated cell sorting (FACS). The isolated cells were characterised with Dolichos biflorus agglutinin (DBA) lectin staining for type A spermatogonia and vimentin-antibody staining for Sertoli cells. A 2 × 2 factorial design was used to investigate the enrichment efficiency on laminin and DSA. In the laminin-enrichment groups, 2 h incubation in plates coated with 20 μg mL–1 laminin yielded a 3.3-fold increase in DBA-positive cells in the adherent fraction, while overnight incubation in flasks coated with 20 μg mL–1 DSA produced a 3.6-fold increase in the non-adherent fraction. However, the greatest enrichment (5.3-fold) of DBA-positive cells was obtained after 2 h incubation in control flasks (coated with bovine serum albumin). Percoll-gradient centrifugation yielded a 3-fold increase in DBA-positive cells. MACS results showed a 3.5- to 5-fold enrichment while FACS produced a 4-fold increase in DBA-positive cells. It is concluded that differential plating is a better method of recovering large numbers of type A spermatogonia for germ cell transplantation, while MACS or FACS can provide highly enriched viable type A spermatogonia for in vitro culture. Further, the combination of differential plating and other enrichment techniques may increase the purification efficiency of type A spermatogonia.

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