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At least 793 records · Page 44Linked to original sources
PubMed2001

[The concentration of trehalose and acitvity of trehalase from Galleria mellonella larvae infected by Steinernema affinis, Bovien 1937 (Nematoda: Rhabditida: Steinernematidae)].

The experimental studies were conducted on caterpillars of wax moth Galleria mellonella infected with Steinernema affinis larvae. The concentration of trehalose and the activity of trehalase were measured during the invasion lasting 48h. The level of trehalose and activity of enzyme were slightly lower in infected insects in comparison to the control animals.

Animals↗
PubMed2006

Purification and characterization of trehalose-6-phosphate synthase from Saccharomycopsis fibuligera A11.

Mutant A11, a mutant of Saccharomycopsis fibuligera Sdu with low acid and neutral trehalase was found to accumulate over 18% (w/w) trehalose from starch in its cells. In this study, trehalose-6-phosphate synthase (Tps1) was purified to homogeneity from this mutant, with a 30-fold increase in the specific enzyme activity, as compared to the concentrated cell-free extract, from initial cells. The molecular mass of the purified enzyme as determined by SDS-PAGE was 66 kDa. The optimum pH and temperature of the purified enzyme were 6.6 and 37 degrees C, respectively. The enzyme was activated by Ca2+, K+ and Mg2+, with K+ showing the highest activation at 35 mM. On the other hand, Mn2+, Cu2+, Fe3+, Hg2+ and Co2+ inhibited the enzyme. The enzyme was also strongly inhibited by protease inhibitors such as iodoacetic acid, EDTA and PMSF.

Cell-Free System↗
PubMed1991

Trehalose-transporting membrane vesicles from yeasts.

We have isolated and characterized a membrane vesicle fraction from yeasts that is capable trehalose transport. The kinetics of the transport system were similar to those seen in the intact cells. The transport depends on a transmembrane pH gradient. If the gradient is collapsed, trehalose accumulated inside the vesicles is leaked into the medium. After aging for several days the ability of the vesicles to transport was lost. However, transport was partially restored by elevating internal pH in the vesicles.

Biological Transport↗
PubMed1991

[Kinetic study of mixed alpha glucosidase activity induced in honeybee hemolymph by in vivo injection of trehalose].

In vivo injection, into emerging bees, of a quantity of trehalose sufficient to double the initial natural haemolymph level of the sugar, leads first to a reduction in the maximal velocity (Vm) of the alpha-glucosidase activity, after 2 hours, followed by an increase in Vm at 6 hours, then a return to normal. The substrate constant (KR) shows minor and insignificant fluctuations about the initial value, and the Hill coefficient (h) a slight, but significant, rise 2 h and 8 h after injection. The simultaneous injection of a protein synthesis inhibitor (ISP) reduces the changes in Vm and h, and lowers value of the ratio Vm/KR from 6 h to 16 h after injection. The overall pattern of results prompts the hypothesis of an intermediary ISP-sensitive induction of an inhibitor of the enzyme-substrate complex, preceding the phase of induction or liberation of active enzyme molecules whose aggregation is subject to a succession of rearrangements alternately favourable to sucrose (lesser specificity) or to trehalose (heightened specificity).

Animals↗
PubMed1988

Aerobic metabolism of trehalose in the taxonomy of coagulase negative staphylococci.

Comparative assays demonstrated that the probability of error was 12.1% when testing the aerobic fermentation of trehalose by coagulase negative staphylococci when this carbohydrate was added to the medium prior to sterilization whereas the error was only 2.7% in media if filtered trehalose was added subsequent to steam sterilization of the medium.

Aerobiosis↗
PubMed1975

[Trehalose, the principle disaccharide of wine].

By gas chromatography of trimethylsilylated derivatives of sugars, trehalose has been shown to be the main disaccharide in wines; its amount can reach 600 mg/l. Other disaccharides identified (sucrose, isomaltose, lactose and turanose) are present in small amounts, seldom above 50 mg/l, sometimes below 5 mg/l. Traces of melibiose and gentiobiose are possible. Conditions of trehalose formation by yeast during fermentation are described. Also technological applications of these results are discussed.

Anion Exchange Resins↗
PubMed1975

[Influence of parenteral injection of trehalose on mammals with different trehalase levels].

Administration of trehalose by parenteral route to mammals (Guinea-pig and rabbit) equipped with Kidney trehalase is followed by rapid hydrolysis of the disaccharide which is excreted in urine only in very low amounts. When the animal under investigation has not trehalase in the kidney (rat), practically the total amount of trehalase is excreted in urine. Perfusion of kidney in rabbit confirms the very rapid hydrolysis of trehalose by this organ.

Animals↗
PubMed1993

The use of trehalose-stabilized lyophilized methanol dehydrogenase from Hyphomicrobium X for the detection of methanol.

The enzyme methanol dehydrogenase (EC 1.1.99.8) from Hyphomicrobium X was used in an attempt to develop a rapid colorimetric test for methanol. The enzyme was stabilized for storage by lyophilization in the presence of the disaccharide trehalose. It was found that the enzyme retained significantly greater activity in the dried state with trehalose than without. The enzyme was partially purified by ammonium sulphate fractionation, after which it was found to be more stable in solution at pH 9 than at pH 7. A procedure is given which involves mixing a defined amount of enzyme with the methanol-containing water together with phenazine methosulphate (PMS), 2-6-dichlorophenol-indophenol (DCPIP) and cyanide, and observing the resultant colour change from blue to yellow if methanol is present. The sensitivity of the procedure is such that 9 mg L-1 of methanol can be readily detected.

2,6-Dichloroindophenol↗
PubMed1995

Effect of trehalose during stress in a heat-shock resistant mutant of Saccharomyces cerevisiae.

Cells of a heat-shock resistant mutant were approximately 1000-times more resistant to lethal heat shock than those of the parental strain. We observed that exponentially growing cells of the mutant synthesized trehalose and showed increased osmotolerance, dehydration tolerance an ethanol tolerance, a fact not observed in wild type strains. The mutant synthesizes constitutively six proteins, among them two proteins of 56 and 63 kDa. Interestingly these molecular weights could correspond to the subunit of trehalose-6-phosphate synthase and to phosphoglucomutase II, respectively. Our results showed that glucose-growing cells of the hsr 1 mutant possessed high levels of activity of these enzymes when compared to the control strain.

Desiccation↗
PubMed1977

[Comparative study of the formation of glycogen and trehalose during starvation in the Lepidoptera Bombyx mori L].

Glycogen reserves are entirely consumed during total starvation of Bombyx mori L. larvae. While the storage of glycogen is lowering and the dietary supply of carbohydrates stopped, the amount of trehalose also decreases but less rapidly than this of glycogen. Relative homeostasis is maintained but only for the ten first hours of inanition. Quantitative evaluation of blood trehalose, which is preformed more rapidly than glycogen analysis, might be used as an efficient test to characterized some physiopathological states.

Animals↗
PubMed1987

Regulation of the trehalose-6-phosphate synthase complex in Saccharomyces. I. Interconversion of forms by phosphorylation.

Trehalose-6-phosphate synthase is another example of an enzyme of carbohydrate metabolism, in Saccharomyces, which could be regulated by interconversion of forms. Deactivation was mediated both in vivo and in vitro by a cyclic AMP-dependent protein kinase. Reversibility of this process was obtained by a phosphatase treatment leading to an increase in activity. The phosphorylated, less active form of the enzyme proved to be more susceptible to activation by ATP.Mg. Mutants with well defined lesions in the cyclic AMP-dependent protein kinase system were used to corroborate our findings of a possible regulatory mechanism of trehalose-6-phosphate synthase activity by interconversion of forms.

Genes↗
PubMed2003

Identification and functional analysis of six mycolyltransferase genes of Corynebacterium glutamicum ATCC 13032: the genes cop1, cmt1, and cmt2 can replace each other in the synthesis of trehalose dicorynomycolate, a component of the mycolic acid layer of the cell envelope.

By data mining in the sequence of the Corynebacterium glutamicum ATCC 13032 genome, six putative mycolyltransferase genes were identified that code for proteins with similarity to the N-terminal domain of the mycolic acid transferase PS1 of the related C. glutamicum strain ATCC 17965. The genes identified were designated cop1, cmt1, cmt2, cmt3, cmt4, and cmt5 ( cmt from corynebacterium mycolyl transferases). cop1 encodes a protein of 657 amino acids, which is larger than the proteins encoded by the cmt genes with 365, 341, 483, 483, and 411 amino acids. Using bioinformatics tools, it was shown that all six gene products are equipped with signal peptides and esterase domains. Proteome analyses of the cell envelope of C. glutamicum ATCC 13032 resulted in identification of the proteins Cop1, Cmt1, Cmt2, and Cmt4. All six mycolyltransferase genes were used for mutational analysis. cmt4 could not be mutated and is considered to be essential. cop1 was found to play an additional role in cell shape formation. A triple mutant carrying mutations in cop1, cmt1, and cmt2 aggregated when cultivated in MM1 liquid medium. This mutant was also no longer able to synthesize trehalose di coryno mycolate (TDCM). Since single and double mutants of the genes cop1, cmt1, and cmt2 could form TDCM, it is concluded that the three genes, cop1, cmt1, and cmt2, are involved in TDCM biosynthesis. The presence of the putative esterase domain makes it highly possible that cop1, cmt1, and cmt2 encode enzymes synthesizing TDCM from trehalose monocorynomycolate.

Arabidopsis Proteins↗
PubMed2005

Isolation and characterization of drought-related trehalose 6-phosphate-synthase gene from cultivated cotton (Gossypium hirsutum L.).

Due to the important role of cotton drought-tolerant varieties and the reported involvement in this trait of trehalose-6-phosphate-synthase, the respective gene (TPS) was isolated and characterized from cultivated cotton, Gossypium hirsutum (ZETA 2 cultivar), using a chromosome-walking technique. TPS has three exons comprising the coding region. Southern blot analysis indicated that the Gossypium genomes (A and D) contain a single copy of TPS per genome. In addition, the expression of this gene was studied in different plant tissues. Plants of the Australian cotton variety Siokra L23, known for its drought tolerance, were subjected to drought stress (using PEG 6,000 solution, for 4 h during the dark period of the day and for four consecutive days); leaves, stems and roots were collected after the end of the stress period. Total extracted RNA was examined for the presence of transcripts, in the above-mentioned tissues of stressed and well-watered plants, by reverse transcription-polymerase chain reaction (RT-PCR). The expression levels, determined semi-quantitatively, indicated that the gene was expressed in all plant tissues under both water availability conditions. However, increased expression levels of TPS were observed mainly in stressed leaves and roots compared to those of the well-watered control. This finding is in agreement with the fact that TPS participates in trehalose biosynthesis, known for its participation in stress signal transduction in higher plants.

Amino Acid Sequence↗
PubMed1996

Cloning and sequencing of trehalose synthase gene from Pimelobacter sp. R48.

The gene encoding trehalose synthase (catalyzing the conversion of maltose into alpha, alpha-trehalose by intramolecular transglucosylation) was cloned from Pimelobacter sp. R48. Sequence analysis revealed a 1719-bp synthase gene and a 573-residue amino-acid sequence. The 220 N-terminal residues were homologous to those of maltases from Saccharomyces carlsbergensis and Aedes aegypti.

Amino Acid Sequence↗
PubMed1989

Presence of two trehalose-6-phosphate synthase enzymes in Candida utilis.

Total trehalose-6-phosphate synthase activity decreased in cell extracts from Candida utilis under conditions inducing activation of the regulatory trehalase by protein kinase catalysed phosphorylation. The synthase activity was reactivated by treatment with alkaline phosphatase revealing the presence of an enzyme whose activity is inactivated by reversible phosphorylation. The occurrence in the trehalose-6-phosphate synthase complex of a second synthase enzyme whose activity is not controlled by phosphorylation and dephosphorylation was demonstrated following gel filtration of cell extracts. The activity of the isolated enzymes was differently modified in vitro by the presence of alkaline phosphatase, ATP, glucose or protein kinase.

Adenosine Triphosphate↗
PubMed1991

Proteolytic activation of alpha,alpha-trehalose 6-phosphate synthase in Candida utilis.

Total trehalose 6-phosphate synthase activity increased in cell-free extracts from Candida utilis following short-term preincubation of the enzyme samples at 37 degrees C. This endogenous activation was prevented by the inhibitors of serine-type proteases, phenylmethylsulfonyl fluoride, antipain or chymostatin, but not by other protease inhibitors such as pepstatin. Fractionation of the cell extracts by Sephadex G-200 gel filtration revealed that the activity of one of the two synthase enzymes present in these cells was enhanced after the activation treatment. These observations indicate the existence of a proteolytically activatable enzyme form in the trehalose 6-phosphate synthase complex of this yeast in addition to the previously characterized enzyme, whose activity appears to be inactivated by reversible phosphorylation.

Candida↗
PubMed2004

Trehalose 6-phosphate synthase from Selaginella lepidophylla: purification and properties.

A protein of 440 kDa with trehalose 6-phosphate synthase activity was purified with only one purification step by immobilized metal affinity chromatography, from fully hydrated Selaginella lepidophylla plants. The enzyme was purified 50-fold with a yield of 89% and a specific activity of 7.05 U/mg protein. This complex showed two additional aggregation states of 660 and 230 kDa. The three complexes contained 50, 67, and 115 kDa polypeptides with pI of 4.83, 4.69, and 4.55. The reaction was highly specific for glucose 6-phosphate and UDP-glucose. The optimum pH was 7.0 and the enzyme was stable from pH 5.0 to 10. The enzyme was activated by low concentrations of Ca2+, Mg2+, K+, and Na+ and by fructose 6-phosphate, fructose, and glucose. Proline had an inhibitory effect, while sucrose and trehalose up to 0.4M did not have any effect on the activity. Neither the substrates nor final product had an inhibitory effect.

Carbohydrate Metabolism↗