scholarly journals Polyprenyl Phosphate Biosynthesis inMycobacterium tuberculosis and Mycobacterium smegmatis

2000 ◽  
Vol 182 (20) ◽  
pp. 5771-5778 ◽  
Author(s):  
Dean C. Crick ◽  
Mark C. Schulbach ◽  
Erin E. Zink ◽  
Marco Macchia ◽  
Silvia Barontini ◽  
...  
Keyword(s):  
Mycobacterium Smegmatis ◽  
Farnesyl Diphosphate ◽  
The Other ◽  
Geranylgeranyl Diphosphate ◽  
Geranyl Diphosphate ◽  
Prenyl Diphosphate ◽  
Specific Activities ◽  
The Difference ◽  
Prenyl Diphosphate Synthase

ABSTRACT Mycobacterium smegmatis has been shown to contain two forms of polyprenyl phosphate (Pol-P), while Mycobacterium tuberculosis contains only one. Utilizing subcellular fractions from M. smegmatis and M. tuberculosis, we show that Pol-P synthesis is different in these species. The specific activities of the prenyl diphosphate synthases in M. tuberculosis are 10- to 100-fold lower than those in M. smegmatis. In M. smegmatis decaprenyl diphosphate and heptaprenyl diphosphate were the main products synthesized in vitro, whereas in M. tuberculosis only decaprenyl diphosphate was synthesized. The data from both organisms suggest that geranyl diphosphate is the allylic substrate for two distinct prenyl diphosphate synthases, one located in the cell membrane that synthesizes ω,E,Z-farnesyl diphosphate and the other present in the cytosol that synthesizes ω,E,E,E-geranylgeranyl diphosphate. In M. smegmatis, the ω,E,Z-farnesyl diphosphate is utilized by a membrane-associated prenyl diphosphate synthase activity to generate decaprenyl diphosphate, and the ω,E,E,E-geranylgeranyl diphosphate is utilized by a membrane-associated activity for the synthesis of the heptaprenyl diphosphate. In M. tuberculosis, however, ω,E,E,E-geranylgeranyl diphosphate is not utilized for the synthesis of heptaprenyl diphosphate. Thus, the difference in the compositions of the Pol-P ofM. smegmatis and M. tuberculosis can be attributed to distinct enzymatic differences between these two organisms.

scholarly journals Novel Medium-Chain Prenyl Diphosphate Synthase from the Thermoacidophilic Archaeon Sulfolobus solfataricus

2002 ◽  
Vol 184 (3) ◽  
pp. 615-620 ◽  
Author(s):  
Hisashi Hemmi ◽  
Satoru Ikejiri ◽  
Satoshi Yamashita ◽  
Tokuzo Nishino
Keyword(s):  
Sulfolobus Solfataricus ◽  
Biological Significance ◽  
Open Reading Frames ◽  
The Other ◽  
Whole Genome Sequence ◽  
Geranylgeranyl Diphosphate ◽  
Product Specificity ◽  
Medium Chain ◽  
Prenyl Diphosphate ◽  
Prenyl Diphosphate Synthase

ABSTRACT Two open reading frames which encode the homologues of (all-E) prenyl diphosphate synthase are found in the whole-genome sequence of Sulfolobus solfataricus, a thermoacidophilic archaeon. It has been suggested that one is a geranylgeranyl diphosphate synthase gene, but the specificity and biological significance of the enzyme encoded by the other have remained unclear. Thus, we isolated the latter by the PCR method, expressed the enzyme in Escherichia coli cells, purified it, and characterized it. The archaeal enzyme, 281 amino acids long, is highly thermostable and requires Mg2+ and Triton X-100 for full activity. It catalyzes consecutive E-type condensations of isopentenyl diphosphate with an allylic substrate such as geranylgeranyl diphosphate and yields the medium-chain product hexaprenyl diphosphate. Despite such product specificity, phylogenetic analysis revealed that the archaeal medium-chain prenyl diphosphate synthase is distantly related to the other medium- and long-chain enzymes but is closely related to eucaryal short-chain enzymes.

Enhancement of ADP-induced Platelet Aggregation by Adrenaline in Vivo and Its Prevention

1973 ◽  
Vol 29 (02) ◽  
pp. 490-498 ◽  
Author(s):  
Hiroh Yamazaki ◽  
Itsuro Kobayashi ◽  
Tadahiro Sano ◽  
Takio Shimamoto
Keyword(s):  
Platelet Count ◽  
Platelet Aggregation ◽  
Platelet Rich Plasma ◽  
The Other ◽  
Endothelial Surface ◽  
Important Interaction ◽  
Blood Coagulability ◽  
The Difference

SummaryThe authors previously reported a transient decrease in adhesive platelet count and an enhancement of blood coagulability after administration of a small amount of adrenaline (0.1-1 µg per Kg, i. v.) in man and rabbit. In such circumstances, the sensitivity of platelets to aggregation induced by ADP was studied by an optical density method. Five minutes after i. v. injection of 1 µg per Kg of adrenaline in 10 rabbits, intensity of platelet aggregation increased to 115.1 ± 4.9% (mean ± S. E.) by 10∼5 molar, 121.8 ± 7.8% by 3 × 10-6 molar and 129.4 ± 12.8% of the value before the injection by 10”6 molar ADP. The difference was statistically significant (P<0.01-0.05). The above change was not observed in each group of rabbits injected with saline, 1 µg per Kg of 1-noradrenaline or 0.1 and 10 µg per Kg of adrenaline. Also, it was prevented by oral administration of 10 mg per Kg of phenoxybenzamine or propranolol or aspirin or pyridinolcarbamate 3 hours before the challenge. On the other hand, the enhancement of ADP-induced platelet aggregation was not observed in vitro, when 10-5 or 3 × 10-6 molar and 129.4 ± 12.8% of the value before 10∼6 molar ADP was added to citrated platelet rich plasma (CPRP) of rabbit after incubation at 37°C for 30 second with 0.01, 0.1, 1, 10 or 100 µg per ml of adrenaline or noradrenaline. These results suggest an important interaction between endothelial surface and platelets in connection with the enhancement of ADP-induced platelet aggregation by adrenaline in vivo.

scholarly journals Volumetric Assessment of Root Canal Obturation Using 3% Nano-Chitosan Versus Zinc Oxide Eugenol (ZOE) and Iodoform-Calcium Hydroxide (Metapex), in Primary Root Canals Shaped with Rotary Versus Manual Methods: A Preliminary In-Vitro Spiral CT Study

2019 ◽  
Author(s):  
Elahe Babashahi ◽  
Maryam Mohmadi Kartalaie ◽  
Leila Basir ◽  
Vahid Rakhshan4
Keyword(s):  
Zinc Oxide ◽  
Calcium Hydroxide ◽  
Primary Root ◽  
In Vitro Study ◽  
The Other ◽  
Root Canals ◽  
Zinc Oxide Eugenol ◽  
Volumetric Assessment ◽  
The Difference

Objectives: In this study, chitosan was introduced and used as a substitute for pulpectomy obturation against conventional materials: zinc oxide eugenol (ZOE) and iodoform-calcium hydroxide (Ca(OH)2) compounds. Also, efficacies of rotary versus manual instrumentations were compared. Materials and Methods: This preliminary in-vitro study was performed on 152 intact non-resorbed root canals of primary molars divided into rotary (n=78) versus hand-instrumentation (n=74) and also into ZOE (n=53), iodoform-Ca(OH)2 (n=50), and 3% nano-chitosan (n=49). Canals were cleaned/shaped using hand or rotary files. Canal spaces were measured using spiral computed tomography (CT). Canals were then obturated using the three materials. The percentages of obturation volume (POV) were estimated. Rotary and manual instrumentations were compared in terms of canal spaces before and after obturation. Three obturation materials were compared in terms of canal spaces after obturation (α=0.05). Results: Average POVs of materials were 96.54% (ZOE), 97.87% (Metapex), and 74.74% (nano-chitosan; P=0.000). POV of chitosan differed from the other two (P=0.000) but the other two were similar (P=0.896). Average POVs were 91.46% (manual) and 88.51% (rotary); the difference was not significant (P=0.322). Pre-obturation spaces of canals for different methods were 3.89 mm3 (manual) and 3.26 mm3 (rotary); the difference was significant (P=0.013). Two-way ANCOVA showed a significant effect of materials (P=0.000) but not root length (P=0.585) or shaping methods (P=0.362) on POVs. Conclusions: Nano-chitosan showed a considerable success rate but it still needs reformulation as it was weaker than the extremely successful commercial competitors. Rotary instrumentation can provide results similar to hand-filing in terms of POV although it might yield smaller canals.

scholarly journals Decaprenyl Diphosphate Synthesis in Mycobacterium tuberculosis

2004 ◽  
Vol 186 (22) ◽  
pp. 7564-7570 ◽  
Author(s):  
Devinder Kaur ◽  
Patrick J. Brennan ◽  
Dean C. Crick
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Divalent Cations ◽  
Expression System ◽  
Catalytic Efficiency ◽  
Farnesyl Diphosphate ◽  
Isopentenyl Diphosphate ◽  
Prenyl Diphosphate ◽  
Mycobacterial Cell Wall ◽  
Prenyl Diphosphate Synthase

ABSTRACT Z-prenyl diphosphate synthases catalyze the sequential condensation of isopentenyl diphosphate with allylic diphosphates to synthesize polyprenyl diphosphates. In mycobacteria, these are precursors of decaprenyl phosphate, a molecule which plays a central role in the biosynthesis of essential mycobacterial cell wall components, such as the mycolyl-arabinogalactan-peptidoglycan complex and lipoarabinomannan. Recently, it was demonstrated that open reading frame Rv2361c of the Mycobacterium tuberculosis H37Rv genome encodes a unique prenyl diphosphate synthase (M. C. Schulbach, P. J. Brennan, and D. C. Crick, J. Biol. Chem. 275:22876-22881, 2000). We have now purified the enzyme to near homogeneity by using an Escherichia coli expression system and have shown that the product of this enzyme is decaprenyl diphosphate. Rv2361c has an absolute requirement for divalent cations and an optimal pH range of 7.5 to 8.5, and the activity is stimulated by both detergent and dithiothreitol. The enzyme catalyzes the addition of isopentenyl diphosphate to geranyl diphosphate, neryl diphosphate, ω,E,E-farnesyl diphosphate, ω,E,Z-farnesyl diphosphate, or ω,E,E,E-geranylgeranyl diphosphate, with Km values for the allylic substrates of 490, 29, 84, 290, and 40 μM, respectively. The Km value for isopentenyl diphosphate is 89 μM. The catalytic efficiency is greatest when ω,E,Z-farnesyl diphosphate is used as the allylic acceptor, suggesting that this is the natural substrate in vivo, a conclusion that is supported by previous structural studies of decaprenyl phosphoryl mannose isolated from M. tuberculosis. This is the first report of a bacterial Z-prenyl diphosphate synthase that preferentially utilizes an allylic diphosphate primer having the α-isoprene unit in the Z configuration, indicating that Rv1086 (ω,E,Z-farnesyl diphosphate synthase) and Rv2361c act sequentially in the biosynthetic pathway that leads to the formation of decaprenyl phosphate in M. tuberculosis.

scholarly journals Controlled-Release SHH Fibrin Scaffold Transplantation Promotes Function Recovery of the Spinal Cord

2017 ◽  
Vol 1 (3) ◽  
Author(s):  
Xu Ming
Keyword(s):  
Spinal Cord ◽  
Controlled Release ◽  
The Other ◽  
Good Effect ◽  
Complete Transection ◽  
Hind Limbs ◽  
Function Recovery ◽  
Fibrin Scaffold ◽  
The Difference

Objective: investigate that the transplantation of sonic hedgehog(SHH) fibrin scaffold promotes recovery of the spinal cord injuryin rats. Method: first, the model of controlled-release SHH fibrinscaffold was made in vitro as the experimental group and observethe controlled-release performance. Second, 60 healthy SD ratswere assigned to prepare models of complete transection of spinalcord, divided into 3 groups: SCI group (simple transection ofspinal cord), FG group (fibrin group), F-SHH group (sonichedgehog-fibrin scaffold transplantation group). Grade hind limbs(BBB) of rats every week. The spinal cord segments were got outin 3 months after operation and went throughimmunohistochemistry and immunoblotting detection. Observe theexpression of NF200, GAP43 and GFAP. Result: (1) SHH Fibrinshowed a good effect of slow release. (2) F-SHH group showed amore significant improvement in BBB score that presented a risingtrend in the whole, compared with the other two groups and thedifference is statistically significant (P < 0.05). (3) The relativeamounts of NF200 and GAP43 in F-SHH group were much higherthan those in the other two groups, while the relative amount ofGFAP was lower and the difference is statistically significant (P <0.05). Conclusion: Controlled-release SHH fibrin scaffoldtransplantation will effectively recover complete spinal cordtransection of rats.

STEROID FORMATION IN PORCINE OVARIAN TISSUE IN VITRO

1969 ◽  
Vol 60 (4) ◽  
pp. 621-634
Author(s):  
Asbjørn Aakvaag
Keyword(s):  
Ovarian Tissue ◽  
Isotope Ratios ◽  
The Other ◽  
Time Study ◽  
Sulphate Group ◽  
Tissue Slices ◽  
Specific Activities ◽  
Endogenous Substrates ◽  
Hydroxy Progesterone

ABSTRACT Ovarian tissue slices from the sow have been incubated simultaneously with pregnenolone and progesterone as substrates, one being labelled with 3H, the other with 14C. Progesterone, 17α-hydroxyprogesterone and androstenedione were isolated in a radiochemically pure form; the isotope ratios and the specific activities were determined after chemical quantitation by gas chromatography. Both substrates were used in the biosynthesis of the isolated compounds. The isotope ratios in progesterone, 17α-hydroxy-progesterone and androstenedione were identical or very similar, indicating that androstenedione was formed solely via the progesterone pathway. The results of a time study were in agreement with this conclusion. From the specific activities of the isolated steroids it appeared that the exogenous radioactivity and endogenous substrates were metabolized in a very similar manner. Pregnenolone sulphate was metabolized to the same isolated steroids. The first step in the conversion of this substrate appeared to be removal of the sulphate group.

scholarly journals Expression, purification, characterization and structure of Pseudomonas aeruginosa arylamine N-acetyltransferase

2005 ◽  
Vol 385 (2) ◽  
pp. 605-612 ◽  
Author(s):  
Isaac M. WESTWOOD ◽  
Simon J. HOLTON ◽  
Fernando RODRIGUES-LIMA ◽  
Jean-Marie DUPRET ◽  
Sanjib BHAKTA ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Mycobacterium Smegmatis ◽  
Protein Crystallization ◽  
Environmental Pollutants ◽  
Nickel Ion ◽  
X Ray Crystallography ◽  
Order Of Magnitude ◽  
Inflammatory Bowel ◽  
Specific Activities

The gene for NAT (arylamine N-acetyltransferase) from Pseudomonas aeruginosa (panat) has been cloned from genomic DNA, and the gene product (PANAT) expressed as an N-terminal histidine-tagged protein in Escherichia coli and purified via nickel ion affinity chromatography. The specific activities of PANAT against a broad range of substrates have been investigated and compared with those of other prokaryotic NAT enzymes. For most arylamine substrates identified, PANAT exhibits in vitro specific activities typically one order of magnitude greater than those of recombinant NAT enzymes from Mycobacterium smegmatis or Salmonella typhimurium. Among the substrates of PANAT so far identified are the anti-tubercular drug isoniazid, 5-aminosalicylate (a drug used in the treatment of inflammatory bowel disease), as well as important environmental pollutants such as 3,4-dichloroaniline and 2-aminofluorene. As well as acetylating common NAT substrates, PANAT is unique among the prokaryotic NATs so far studied in acetylating the folate precursor 4-aminobenzoic acid and the folate catabolite 4-aminobenzoylglutamate. The recombinant protein has been expressed in sufficient quantity to allow protein crystallization, and we have subsequently determined the 1.95 Å structure of PANAT by X-ray crystallography.

The Herbicide Command Does Not Inhibit the Prenyl Diphosphate-Forming Enzymes in Plastids

1990 ◽  
Vol 45 (7-8) ◽  
pp. 856-858 ◽  
Author(s):  
Manfred Lützow ◽  
Peter Beyer ◽  
Hans Kleinig
Keyword(s):  
Mode Of Action ◽  
Phytoene Synthase ◽  
Geranylgeranyl Diphosphate ◽  
Prenyl Diphosphate ◽  
Prenyl Transferase

Abstract The herbicide Comm and (2-(2-chlorophenyl)methyl-4,4-dimethyl-3-isoxazolidinone) does not affect the in vitro activities of the plastid enzymes catalyzing the steps leading from isopen­ tenyl diphosphate to geranylgeranyl diphosphate and phytoene, i.e. the isopentenyl diphos­ phate isomerase, prenyl transferase and phytoene synthase. The extractable activities of these enzymes in herbicide-treated seedlings are also not affected. Nevertheless, the synthesis of chlorophylls and carotenoids in treated seedlings is severely inhibited in vivo. The mode of action of Comm and remains still unknown.

scholarly journals EFFECT OF AGE ON SOME ASPECTS OF SULFATE METABOLISM IN THE RAT

1954 ◽  
Vol 99 (3) ◽  
pp. 283-298 ◽  
Author(s):  
Dominic D. Dziewiatkowski
Keyword(s):  
Serum Proteins ◽  
Age Groups ◽  
Intraperitoneal Dose ◽  
Sulfate Metabolism ◽  
Old Rats ◽  
Specific Activities ◽  
The Difference ◽  
Effect Of Age ◽  
Two Age Groups

S35-labelled sodium sulfate was administered to rats 10, 30, and 300 days old in an intraperitoneal dose of 0.3 µc. per gm. of body weight. Representative animals of each age were sacrificed 12, 24, 48, and 96 hours after injection. The concentration of sulfur-35 in the pooled sera of the 10-day-old rats was found to be strikingly higher than the level in the sera of the 30-day-old and the 300-day-old rats, while the levels of sulfur-35 in the sera of rats in the latter two age groups were similar. The difference was not explained by the differences in binding of sulfate by serum proteins. Although no binding could be detected when sulfate was added to serum in vitro, a substantial fraction, up to 80 per cent by the 96th hour, was observed to be bound after injection into the living rat. The 10-day-old rats differed from the older ones in having lower levels of serum proteins and lesser amounts of bound sulfate. The non-dialyzable sulfur-35 was associated to the largest extent with the albumin component in the sera. The age of the rats found expression in the specific activities of the sulfate-sulfur of mucopolysaccharides isolated from the skeletons, pelts, and viscera. The highest specific activities were observed in the mucopolysaccharides isolated from the tissues of the youngest rats; the lowest in those from the oldest rats. Though the maximum concentration was rapidly attained in the mucopolysaccharides from the various tissues in each of the age groups, the subsequent decreases in concentration were slow. Radiochemical analyses for sulfur-35 in ends and shafts of femurs and radioautographs of humeri supported the assumption that the labelled sulfate had been incorporated into the chondroitin sulfate of growing cartilage.

Sign in / Sign up

Export Citation Format

Share Document