Activities of citrate synthase and other enzymes of <i>Acetobacter xylinum in situ</i> and <i>in vitro</i>

Swissa, M; Weinhouse, Haim; Benziman, Moshe

doi:10.1042/bj1530499

Cited by 26 publications

(14 citation statements)

References 15 publications

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“…[12]. ATP, NADH and NADPH are also found to inhibit the citrate synthase or glucose-6-p dehydrogenase, which inactivate the citrate cycle or pentose cycle [13,14]. Apparantly the oxidative dissimilation of carbohydrates is unfavourable for the cellulose synthesis, so to restrain the channelling of sugar carbon into the TCA cycle or pentose cycle by addition of citric acid or succinic acid may effect the cellulose production increase.…”

Section: Effect Of Succinic Acid-buffer Systemmentioning

confidence: 99%

The Importance of TCA Cycle Related Acids in Bacterial Cellulose Production

et al. 1999

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Section: Effect Of Succinic Acid-buffer Systemmentioning

confidence: 99%

The Importance of TCA Cycle Related Acids in Bacterial Cellulose Production

et al. 1999

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“…These fibrils exist in a parallel chain crystalline lattice, although the antiparallel chain lattice, cellulose II, is thermodynamically favored (1,2). More progress has been made toward understanding the biochemistry of polymerization than toward understanding the biogenesis of the fibrils, partly because the attempts to achieve in vitro synthesis of cellulose I by cell-free preparations have proved to be inconclusive (3)(4)(5)(6)(7).…”

mentioning

confidence: 99%

Cellulose biogenesis: Polymerization and crystallization are coupled processes in Acetobacter xylinum

Benziman

Haigler

Brown

et al. 1980

Proc. Natl. Acad. Sci. U.S.A.

209

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Calcofluor White ST, a stilbene derivative used commercially as an optical brightener for cellulose, increased the rate of glucose polymerization into cellulose by resting cells of the gram-negative bacterium Acetobacter xylinum. This bacterium normally produces a ribbon of cellulose that is a composite of crystalline microfibrils. In concentrations above 0.1 mM, Calcofluor disrupts the assembly of crystalline cellulose I microfibrils and their integration into a composite ribbon by stoichiometric binding to glucose residues of newly polymerized glucan chains. Under these conditions, the rate of glucose polymerization increases up to 4 times the control rate, whereas oxygen uptake increases only 10-15%. These observed effects are readily reversible. If free Calcofluor is washed away or depleted below the threshold value by binding to cellulose as polymerization continues, ribbon production and the normal rate of polymerization resume. It is concluded that polymerization and crystallization are cell-directed, coupled processes and that the rate of crystallization determines the rate of polymerization. It is suggested that coupling must be maintained

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“…The present work suggests that the pores produced in the membranes of Atriplex roots were probably in the range of 0.5 to 0.7 nm in radius since sugars, amino acids, and short chain organic acids could diffuse out relatively freely, whereas NAD was not able to reach the site of alcohol dehydrogenase. The pores induced in the membranes of microorganisms would appear to be larger since NAD passes freely (16,19,20). The slow outward diffusion of fluorescein from the cytoplasm observed under the fluorescence microscope is in accordance with the conclusion that the pores induced are not much larger than the Stokes radii of this molecule.…”

mentioning

confidence: 99%

Induction of “Pore” Formation in Plant Cell Membranes by Toluene

Lerner

Ben-Bassat²,

Reinhold³

et al. 1978

Plant Physiol.

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Treatment with aqueous toluene-ethanol has been shown to induce "pore" formation in plant cell membranes. The evidence i as folows: Althoug the phenomenon of pore induction is qultatively simlar to that in microorganisms, the pores induced appear to be smaler. It is proposed that induced leakage could be the bas for the development of simple and rapid methods for plant biochemial studies.Biochemical studies of cells provided with hard outer walls are hindered by the technical difficulties involved in homogenization. In the case of microorganisms a way of bypassing these difficulties has been developed. The formation of small holes is induced in the cell membrane by suitable techniques, the simplest being treatment with toluene (2, 5-7, 10, 12, 14-16, 19, 20 Preloading of the cytoplasm with fluorescein was achieved by incubating the roots for 10 min at room temperature in a 10 mm solution of KH2PO4 containing 1 mg of fluorescein/10 ml.Loading with ANS2 was achieved by incubating the roots for 10 min at room temperature in a 50 gM solution of ANS brought to pH 6 by addition of dilute NaOH containing 1% toluene and 4% ethanol.Cytoplasmic fluorescence induced by either fluorescein or ANS was observed with a Leitz Ortholux fluorescence microscope using transmission filters BG38 (4 mm) plus BG12 (3 mm) and suppression filter K530. Preloading of the vacuoles with neutral red was achieved by incubating the roots in an aqueous solution of the dye (1 mg/10 ml). Potassium phosphate buffer (pH 7.5) was then added to a final concentration of 10 mm and incubation continued for 1 hr. Although neutral red precipitates at this pH, the non-ionized species which is formed is lipid-soluble and penetrates the cellular membranes. After incubation the roots were rinsed several times in distilled H20.The procedure for compartment analysis was essentially similar to that described by Glinka (3). Course of influx of '4C-thiourea into Atriplex root at room temperature was found to be considerably faster than into carrot root. After 1 hr the labeled thiourea had reached equilibrium with the tissue. Atriplex roots were therefore loaded by incubation in 50 mm 14C-thiourea for 1 hr at room temperature. Efflux was measured by transferring the roots, in a holder, sequentially through a series of vials containing 6 ml of 50 mm nonradioactive thiourea. The vials were shaken constantly and were maintained at 4 C to slow down the process. During the first 2 min the roots were transferred every 15 sec to wash off the radioactivity adhering to the holder and to the surface of the roots. Subsequent efflux periods were progressively longer and continued for 3 hr.

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Activities of citrate synthase and other enzymes of Acetobacter xylinum in situ and in vitro

Cited by 26 publications

References 15 publications

The Importance of TCA Cycle Related Acids in Bacterial Cellulose Production

The Importance of TCA Cycle Related Acids in Bacterial Cellulose Production

Cellulose biogenesis: Polymerization and crystallization are coupled processes in Acetobacter xylinum

Induction of “Pore” Formation in Plant Cell Membranes by Toluene

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