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PubMed2001

Haemolymph sugar levels in foraging honeybees (Apis mellifera carnica): dependence on metabolic rate and in vivo measurement of maximal rates of trehalose synthesis.

Previous investigations of haemolymph sugar levels in honeybees have reported very different results, probably because different experimental conditions affected the activity levels of the animals. The present study investigated the dependence of haemolymph sugar levels in foraging honeybees on metabolic rate and whether the haemolymph sugar level is regulated. Free-flying foraging bees were trained to collect controlled amounts of sucrose solution of different concentrations (15%, 30% or 50% sucrose w/w). Immediately after feeding, metabolic rate was measured over a given time depending on the sucrose concentration, then crop-emptying rate and haemolymph sugar levels were measured. Bees exhibiting a wide range of metabolic rates were compared to establish whether the observed differences in haemolymph sugar levels were due to limits in the supply of sugars from the crop or in the rate of trehalose synthesis in the fat bodies. Independent of the concentration of the sucrose solution supplied, haemolymph trehalose, glucose and fructose levels were constant for metabolic rates from 0 to 4.5 ml CO(2)h(-1). At higher metabolic rates, trehalose concentration decreased while that of glucose and fructose increased, with the exception of bees fed 15% sucrose solution. As the supply of sugar from the crop via the proventriculus was sufficient to support even the highest metabolic rates, the observed pattern must result from an upper limit in the capacity of the fat body to synthesise trehalose. The maximal rate of conversion of glucose to trehalose in the fat body was therefore calculated to average 92.4 microg glucosemin(-1). However, for bees fed 15% sucrose solution both the rate of conversion of glucose to trehalose and the rate of sugar transport from the crop to the ventricle were limited, together resulting in a decrease in total haemolymph sugar levels for metabolic rates higher than 5 ml CO(2)h(-1).

Animals↗
PubMed2003

Trehalose-induced changes of the ethidium hydration shell detected by time-resolved fluorescence.

The fluorescence lifetime of ethidium bromide (EB), a widely used fluorescent dye, has been monitored in water solution versus trehalose concentration in order to learn how the presence of the disaccharide modifies the hydration of EB, which is used in this study as a model probe. The interest in trehalose, a naturally occurring bioprotector (osmolyte), stems from its ability to stabilize biomolecules under stress situations. The observed effects of trehalose on EB fluorescence properties have been compared with those induced by sucrose and glucose. Lifetime measurements have been performed by frequency domain fluorometry (2-40 MHz), and from the analysis of their changes versus sugar concentration, the EB-sugar interaction parameters have been obtained. The effect of trehalose on the EB decay in glasses has also been studied both by exploring the heterogeneity of lifetime decay and by single-molecule imaging. Trehalose appears to be more efficient in changing the EB fluorescence parameters, such as the emission lifetime, and it leads to a degree of heterogeneity higher than that induced by the other sugars. When EB is embedded in trehalose glasses, the heterogeneity of the emission and of the bleaching time is further enhanced.

Ethidium↗
PubMed2004

[Establishment and evaluation on the method for platelet intracellular trehalose determination].

This study was aimed to establish an applicable, convenient and rapid method for platelet intracellular trehalose determination, so that the technique of trehalose loading could be optimized and used in research on freeze-drying platelets. Protein from loaded-trehalose platelets was deposited by using trichloroacetic acid, trechalose concentration in platelets was determinated by sulfuric-anthrone reaction and was analyzed by high performance liquid chromatography (HPLC). The results showed that when platelets were loaded with 1.7% of trehalose in loading solution, intracellular concentration determinated by sulfuric-anthrone reaction was 0.22% and derterminated by HPLC was 0.2%. The recovery rate of trehalose determinated by sulfuric-anthrone reaction was 100.7% and stability and repeatability of results were good. In conclusion, the method is convenient, rapid, accurate and highly sensitive for determination of platelet intracellar trehalose.

Blood Platelets↗
PubMed2001

Trehalose accumulation from soluble starch by Saccharomycopsis fibuligera sdu.

Trehalose accumulation from starch by Saccharomycopsis fibuligera sdu was examined in 300-ml shaken flask culture and Biostat B(2) 2-1 fermentation. In the 300-ml flask, 16.5% (w/w) trehalose accumulated in the yeast cells (cell dry weight) was observed with 100-ml medium shaken at 200 rpm for 50 h at 30 degrees C. We found that 1.0% soluble starch in the medium was most suitable for trehalose accumulation by this yeast strain. In the Biostat B(2) 2-1 fermentor, 18.0% (w/w) trehalose accumulated in the yeast cells (cell dry weight) was observed within 48 h of fermentation when agitation speed was 200 rpm. The trehalose obtained from the yeast cells was identical to standard trehalose from Sigma based on the analysis results of High-Performance Exchange Anionic Chromatography (HPEAC).

Journal Article↗
PubMed2001

Trehalose suppresses lipopolysaccharide-induced osteoclastogenesis bone marrow in mice.

We have previously shown that trehalose suppresses bone loss in ovariectomized (OVX) mice by way of inhibiting osteoclast differentiation in bone marrow. Also, trehalose inhibits the secretion of interleukin-6 in bone marrow cell cultures, resulting in a decrease in osteoclast formation. In this study, we examined the effect of trehalose on osteoclastogenesis using another model of bone resorption, namely lipopolysaccharide (LPS)-stimulated osteoclast induction. Mice were given trehalose (1g/kg) by gastric intubation for 5 consecutive days, and 24 hours later, 14 mg/kg of LPS was injected intraperitoneally. Trehalose significantly suppressed LPS-induced tumor necrosis factor (TNF)-alpha production after 90 min and decreased the number of osteoclasts in the bone marrow 48 hours after LPS injection. These results indicate that trehalose suppresses excessive osteoclastogenesis not only in OVX mice but also in a LPS-induced bone resorption mouse model and further suggest that the latter finding may be mediated at least in part through a decrease in TNF-alpha production.

Journal Article↗
PubMed2006

Structural investigation of the confinement of finite amounts of trehalose in water-containing sodium Bis(2-ethylhexyl)sulfosuccinate reversed micelles.

The structural effect of trehalose confined in water-containing sodium bis(2-ethylhexyl)sulfosuccinate (AOT) reversed micelles at water to AOT molar ratio W = 5 and 10 as a function of the trehalose to AOT molar ratio T (0 < T < 0.1) has been investigated by small-angle neutron scattering (SANS). SANS data analysis is consistent with the hypothesis that trehalose is encapsulated within the quite spherical hydrophilic micellar cores of water-containing reversed micelles, causing an increase of the aggregate size and a decrease of the polydispersion. Moreover, SANS results suggest that the trehalose confinement in water-containing reversed micelles involves marked changes on the molecular packing of the water-containing micellar cores. In particular, according to the obtained findings, we can hypothesize the intercalation of the trehalose molecules between the polar surfactant headgroups. The preferential solubilization in this specific nanodomain could explain the trehalose capability to prevent, upon dehydration, the transition to a gel phase, hindering serious damage to biostructures.

Journal Article↗
PubMed2004

Arabidopsis trehalose-6-phosphate synthase 1 is essential for normal vegetative growth and transition to flowering.

In resurrection plants and yeast, trehalose has a function in stress protection, but the absence of measurable amounts of trehalose in other plants precludes such a function. The identification of a trehalose biosynthetic pathway in angiosperms raises questions on the function of trehalose metabolism in nonresurrection plants. We previously identified a mutant in the Arabidopsis trehalose biosynthesis gene AtTPS1. Plants homozygous for the tps1 mutation do not develop mature seeds (Eastmond et al., 2002). AtTPS1 expression analysis and the spatial and temporal activity of its promoter suggest that this gene is active outside the seed-filling stage of development as well. A generally low expression is observed in all organs analyzed, peaking in metabolic sinks such as flower buds, ripening siliques, and young rosette leaves. The arrested tps1/tps1 embryonic state could be rescued using a dexamethasone-inducible AtTPS1 expression system enabling generation of homozygous mutant plants. When depleted in AtTPS1 expression, such mutant plants show reduced root growth, which is correlated with a reduced root meristematic region. Moreover, tps1/tps1 plants are retarded in growth and remain generative during their lifetime. Absence of Trehalose-6-Phosphate Synthase 1 in Arabidopsis plants precludes transition to flowering.

Arabidopsis↗
PubMed1981

Trehalose Toxicity in Cuscuta reflexa: CORRELATION WITH LOW TREHALASE ACTIVITY.

A toxic effect of alpha,alpha-trehalose in an angiospermic plant, Cuscuta reflexa (dodder), is described. This disaccharide and its analogs, 2-aminotrehalose and 4-aminotrehalose, induced a rapid blackening of the terminal region of the vine which is involved in elongation growth. From the results of in vitro growth of several angiospermic plants and determination of trehalase activity in them, it is concluded that the toxic effect of trehalose in Cuscuta is because of the very low trehalase activity in the vine. As a result, trehalose accumulates in the vine and interferes with some process closely associated with growth. The growth potential of Lemna (a duckweed) in a medium containing trehalose as the carbon source was irreversibly lost upon addition of trehalosamine, an inhibitor of trehalase activity. It is concluded that, if allowed to accumulate within the tissue, trehalose may be potentially toxic or inhibitory to higher plants in general. The presence of trehalase activity in plants, where its substrate has not been found to occur, is envisaged to relieve the plant from the toxic effects of trehalose which it may encounter in soil or during association with fungi or insects.

Journal Article↗
PubMed1993

Purification of trehalose synthase from baker's yeast. Its temperature-dependent activation by fructose 6-phosphate and inhibition by phosphate.

A trehalose synthase purified from baker's yeast contained 56-kDa, 102-kDa and 123-kDa polypeptides as its main components. The 102-kDa polypeptide was isolated and shown to be a specific trehalose-6-phosphatase. The trehalose-6-phosphate synthase (Tre6P synthase) activator described by Londesborough and Vuorio [(1991) J. Gen. Microbiol. 137, 323-330] was shown to be phosphoglucoisomerase and to function entirely by generating fructose 6-phosphate. Below 35 degrees C, fructose 6-phosphate is a powerful activator of the Tre6P synthase activity of intact trehalose synthase, especially at physiological phosphate concentration, but does not affect its trehalose-6-phosphatase activity nor the Tre6P synthase activity of truncated trehalose synthase containing truncated versions of the 123-kDa polypeptide. At 50 degrees C, activation by fructose 6-phosphate and inhibition by phosphate are greatly decreased, resulting in an unusually high temperature-dependence for the Tre6P synthase activity at a physiological phosphate concentration (2 mM).

Amino Acid Sequence↗
PubMed2004

Genetic modification of photosynthesis with E. coli genes for trehalose synthesis.

Improvement in photosynthesis per unit leaf area has been difficult to alter by breeding or genetic modification. We report large changes in photosynthesis in Nicotiana tabacum transformed with E. coli genes for the trehalose pathway. Significantly, photosynthetic capacity (CO2 assimilation at varying light and CO2, and quantum yield of PSII electron transport) per unit leaf area and per leaf dry weight were increased in lines of N. tabacum transformed with the E. coli gene otsA, which encodes trehalose phosphate synthase. In contrast, transformation with otsB, which encodes trehalose phosphate phosphatase or Trec, encoding trehalose phosphate hydrolase, produced the opposite effect. Changes in CO2 assimilation per unit leaf area were closely related to the amount and activity of Rubisco, but not to the maximum activities of other Calvin cycle enzymes. Alterations in photosynthesis were associated with trehalose 6-phosphate content rather than trehalose. When growth parameters were determined, a greater photosynthetic capacity did not translate into greater relative growth rate or biomass. This was because photosynthetic capacity was negatively related to leaf area and leaf area ratio. In contrast, relative growth rate and biomass were positively related to leaf area. These results demonstrate a novel means of modifying Rubisco content and photosynthesis, and the complexities of regulation of photosynthesis at the whole plant level, with potential benefits to biomass production through improved leaf area.

Journal Article↗
PubMed2002

Neurospora clock-controlled gene 9 (ccg-9) encodes trehalose synthase: circadian regulation of stress responses and development.

The circadian clock of Neurospora crassa regulates the rhythmic expression of a number of genes encoding diverse functions which, as an ensemble, are adaptive to life in a rhythmic environment of alternating levels of light and dark, warmth and coolness, and dryness and humidity. Previous differential screens have identified a number of such genes based solely on their cycling expression, including clock-controlled gene 9 (ccg-9). Sequence analysis now shows the predicted CCG-9 polypeptide to be homologous to a novel form of trehalose synthase; as such it would catalyze the synthesis of the disaccharide trehalose, which plays an important role in protecting many cells from environmental stresses. Consistent with this, heat, glucose starvation, and osmotic stress induce ccg-9 transcript accumulation. Surprisingly, however, a parallel role in development is suggested by the finding that inactivation of ccg-9 results in altered conidiophore morphology and abolishes the normal circadian rhythm of asexual macroconidial development. Examination of a clock component, FRQ, in the ccg-9-null strain revealed normal cycling, phosphorylation, and light induction, indicating that loss of the conidiation rhythm is not due to changes in either the circadian oscillator or light input into the clock but pointing instead to a defect in circadian output. These data imply an interplay between a role of trehalose in stress protection and an apparent requirement for trehalose in clock regulation of conidiation under constant environmental conditions. This requirement can be bypassed by a daily light signal which drives a light-entrained rhythm in conidiation in the ccg-9-null strain; this bypass suggests that the trehalose requirement is related to clock control of development and not to the developmental process itself. Circadian control of trehalose synthase suggests a link between clock control of stress responses and that of development.

Circadian Rhythm↗
PubMed1967

Carbohydrate metabolism in streptomycetes. II. Isolation and enzymatic synthesis of trehalose.

A number of streptomycetes were examined for their ability to synthesize trehalose phosphate as well as for the presence of alpha,alpha-trehalose. In each case, an enzyme system was demonstrated which catalyzed the transfer of glucose from guanosine diphosphate-glucose to glucose-6-phosphate to form trehalose phosphate. Thus, this group of organisms appears to synthesize trehalose phosphate by a different mechanism from that described in insects, yeast, and fungi. In addition, trehalose was isolated from each of these organisms. In several of these cases, crystallization of the sugar and determination of the physical properties showed that the sugar was alpha,alpha-trehalose.

Chromatography, Paper↗
PubMed1996

A regulatory role for TSL1 on trehalose synthase activity.

UDPG-dependent trehalose synthase activity was determined during growth on glucose medium in controls and yeast strains having deletions on components of the trehalose phosphate synthase complex. Deletion of TPS3 produced any alteration. In contrast, strains harboring deletions tsl1 delta or tsl1 delta/tps3 delta showed no activation of enzyme after glucose exhaustion. To evaluate the role played by TPS3 and TSL1 on trehalose synthase activity we have determined the effect of the addition of a cell free extract from a strain expressing only TPS3 and TSL1 to extracts of strains lacking TSL1, TPS3 or both. No effect was observed on trehalose synthase activity from tps3 delta mutant. The addition of the same extract to trehalose synthase from tsl1 delta or tsl1 delta/tps3 delta strains showed a two-fold activating effect, indicating that TPS3 and TSL1 regulated differently the UDPG-dependent trehalose synthase activity.

Glucose↗
PubMed2005

Molecular dynamics simulation of sucrose- and trehalose-coated carboxy-myoglobin.

We performed a room temperature molecular dynamics (MD) simulation on a system containing 1 carboxy-myoglobin (MbCO) molecule in a sucrose-water matrix of identical composition (89% [sucrose/(sucrose + water)] w/w) as for a previous trehalose-water-MbCO simulation (Cottone et al., Biophys J 2001;80:931-938). Results show that, as for trehalose, the amplitude of protein atomic mean-square fluctuations, on the nanosecond timescale, is reduced with respect to aqueous solutions also in sucrose. A detailed comparison as a function of residue number evidences mobility differences along the protein backbone, which can be related to a different efficacy in bioprotection. Different heme pocket structures are observed in the 2 systems. The joint distribution of the magnitude of the electric field at the CO oxygen atom and of the angle between the field and the CO unit vector shows a secondary maximum in sucrose, absent in trehalose. This can explain the CO stretching band profile (A substates distribution) differences evidenced by infrared spectroscopy in sucrose- and trehalose-coated MbCO (Giuffrida et al., J Phys Chem B 2004;108:15415-15421), and in particular the appearance of a further substate in sucrose. Analysis of hydrogen bonds at the protein-solvent interface shows that the fraction of water molecules shared between the protein and the sugar is lower in sucrose than in trehalose, in spite of a larger number of water molecules bound to the protein in the former system, thus indicating a lower protein-matrix coupling, as recently observed by Fourier transform infrared (FTIR) experiments (Giuffrida et al., J Phys Chem B 2004;108:15415-15421).

Binding Sites↗
PubMed1993

Protective role of trehalose during heat stress in Saccharomyces cerevisiae.

Yeast cells accumulate the disaccharide trehalose in response to certain stress conditions. In an attempt to verify the role that trehalose plays when yeast cells are faced with heat stress, yeast mutant strains with specific lesions in trehalose metabolism were used. Cultures growing exponentially on glucose were shifted from 28 to 40 degrees C for 1 h. Accumulation of trehalose was correlated with heat tolerance, measured as resistance to 50.5 degrees C. Additionally, it was observed that the trehalose carrier was not involved in the mechanism of thermotolerance acquisition. Mutants that lack the carrier were also able to acquire thermotolerance as long as synthesis of the disaccharide took place.

Adaptation, Physiological↗
PubMed1999

A dual role for intracellular trehalose in the resistance of yeast cells to water stress.

It is well known that yeast cells survive environmental stresses such as desiccation and freezing and there is evidence that these phenomena may be related to the presence of trehalose in the cells. However, the molecular mechanism by which trehalose might exert an influence on cell functions remains unknown. In this report, thermogravimetry and differential thermal analysis were used to estimate the amount of bound water in yeast cells. It is shown that when the trehalose content is greater than 2-3% of the cell dry weight, the amount of bound water is drastically decreased and the viability of the dried cells is increased. This implies that a major portion of the bound water is replaced by trehalose. In addition, measurements of the NMR spin-lattice relaxation time of the intracellular water protons show that trehalose acts as a water-structuring agent in hydrated yeast cells. This dual role is essential for high resistance to water stress in yeast cells.

Intracellular Fluid↗
PubMed2001

Human platelets loaded with trehalose survive freeze-drying.

Human blood platelets are stored in blood banks for 5 days, after which they are discarded, by federal regulation. This short lifetime has led to a chronic shortage of platelets, a problem that is particularly acute in immunosuppressed patients, such as those with AIDS. We report here that platelets can be preserved by freeze-drying them with trehalose, a sugar found at high concentrations in organisms that naturally survive drying. We suggest that these findings will obviate the storage problem with platelets. Trehalose is rapidly taken up by human platelets at 37 degrees C, with loading efficiencies of 50% or greater. Fluid-phase endocytosis plays an important role in this efficient uptake of trehalose, but other mechanisms may also be involved. Trehalose-loaded platelets were successfully freeze-dried, with excellent recovery of intact platelets. Rehydration from the vapor phase led to a survival rate of 85%. The response of these platelets to the agonists thrombin (1 U/ml), collagen (2 microg/ml), ADP (20 micromM), and ristocetin (1.6 mg/ml) was almost identical to that of fresh, control platelets. Analysis by Fourier transform infrared spectroscopy demonstrated that the membrane and protein components of trehalose-loaded platelets after freeze-drying, prehydration, and rehydration were remarkably similar to those of fresh platelets.

Biological Transport, Active↗
PubMed2001

The trehalose myth revisited: introduction to a symposium on stabilization of cells in the dry state.

This essay is an introduction to a series of papers arising from a symposium on stabilization of cells in the dry state. Nearly all of these investigations have utilized the sugar trehalose as a stabilizing molecule. Over the past two decades a myth has grown up about special properties of trehalose for stabilization of biomaterials. We review many of such uses here and show that under ideal conditions for drying and storage trehalose has few, if any, special properties. However, under suboptimal conditions trehalose has some distinct advantages and thus may remain the preferred excipient. We review the available mechanisms for introducing trehalose into the cytoplasm of living cells as an introduction to the papers that follow.

Animals↗