Trehalose Content Research Articles

The Improvement of Reserve Polysaccharide Glycogen Level and Other Quality Parameters of S. cerevisiae Brewing Dry Yeasts by Their Rehydration in Water, Treated with Low-Temperature, Low-Pressure Glow Plasma (LPGP)

The increasing popularity of active dry yeast arises from its properties, such as ease of storage, and simplicity of preparation and dosing. Herein, we elaborate on the effect of plasma-treated water (PTW) under air atmosphere (PTWAir) and nitrogen (PTWN) on the improvement of the reserve polysaccharide glycogen level and other quality parameters of S. cerevisiae brewing dry yeast in comparison with the non plasma-treated water (CW). For this purpose, strains of top-fermenting (S. cerevisiae T58 (poor quality), S33 (poor quality)) and bottom-fermenting (S. pastorianus W30/70 (poor quality)) yeast stored one year after opening and S. cerevisiae US-05 (fresh strain) were selected to examine the influence of PTWs toward the quality parameters of yeast biomass after the rehydration and fermentation process. The obtained results showed that in the case of poor quality yeast strains, PTWAir increased glycogen content after the rehydration and fermentation process, which was a favorable trend. A similar increase was observed for the trehalose content. Results showed that PTWN significantly reduced the number of yeast cells in ale strains and the viability of all analyzed samples. The lowest viability was observed in Sc S33 strain for PTWAir (41.99%), PTWN (18.6%) and CW (22.86%). PTWAir did not contribute to reducing the analyzed parameter; in particular, the results of Sc T58 yeast strain’s viability are shown: PTWAir (58.83%), PTWN (32.28%) and CW (43.56%). The obtained results suggest that rehydration by PTWN of dry yeast with a weakened condition is not recommended for both qualitative and cost-related reasons, while PTWAir significantly contributed to the improvement of some yeast parameters after rehydration and fermentation (higher glycogen and trehalose content).

Predation preference and nutritional values of four different aphid species for Orius sauteri (Hemiptera: Anthocoridae)

BackgroundOrius sauteri (Poppius) is one of the important natural enemies of aphids in Asia. Understanding its predation preference and efficiency can help improve its effectiveness as a biological control agent. Here, the predation preference of O. sauteri adults toward Aphis craccivora Koch, Rhopalosiphum maidis (Fitch), Myzus persicae Sulzer, and Aphis gossypii Glover was studied.ResultsThe research found that O. sauteri had good predation efficiency on four important aphid species. Orius sauteri killed a similar number of four aphids in non-selective tests, but it preferred to eat more R. maidis and A. gossypii, and fewer A. craccivora in selective tests. The main biochemical components of the four aphid species were analyzed, including water content and nutritional components along with body mass. Rhopalosiphum maidis had a significantly lower water content than A. craccivora. Orius sauteri preferred R. maidis and A. gossypii, which harbored higher lipid and trehalose content, while preying on fewer A. craccivora, which had a larger body weight for the supplement of water and nutrition. The predation preference may be due to the closest nutrition composition to the optimal intake of O. sauteri.ConclusionsThis study showed that the predatory selection of O. sauteri was closely associated with the water content, bodyweight, lipid, and trehalose levels of prey, while the glycogen content and protein level might be less determinant. The high predation capacity on four aphids of O. sauteri indicated the great potential to integrate this predator into biological control strategies against aphids.

Study of Water Distribution, Textural and Colour Properties of Cold Formulated and Air-Dried Apple Snacks.

Vacuum impregnation is considered a cold formulation technology since it allows the incorporation of a desired functional compound into porous plant tissue without applying any heat. It is widely used in combination with the drying process to obtain added-value snacks. The aim of this work was to evaluate the effect of two trehalose concentrations (5 and 10% w/w) on: (i) the water state and texture evolution during the air drying (50 °C, 8 h) of apple snacks vacuum impregnated with blueberry juice, and on (ii) the colour of the final dried apple snacks. The results of nuclear magnetic resonance (NMR) showed that trehalose affects the water mobility of the samples during drying especially after 200–300 min of drying. In terms of textural properties, trehalose could increase the crispier characteristic of the samples impregnated with trehalose at the end of drying. Significative changes were found in terms of chroma and hue angle.

Evaluation of PEG and sugars consolidated fragile waterlogged archaeological wood using nanoindentation and ATR-FTIR imaging

Waterlogged archaeological wood (WAW) undergoes biological deterioration during long-term immersion in microorganisms-rich aquatic environments. The consolidants are commonly applied to avoid wood deformation upon drying. It is urgent to develop a systematic evaluation method to study the impact of the consolidant distribution and the intermolecular interactions among consolidants and cell wall components on the improvement of wood mechanical traits. In order to evaluate the effect of consolidant distribution and intermolecular interactions between consolidants and cell wall components on the mechanical improvement, herein, we proposed in situ analysis methods involving Nanoindentation (NI) technology (without prior embedding) along with attenuated total reflection Fourier transform infrared imaging (ATR-FTIR imaging). Moreover, PEG, sucralose, and trehalose were chosen as representative consolidants to treat moderately deteriorated WAW because of their different molecular weights and different hydrophilic groups. Results showed that the mechanical improvement in consolidated WAW was significant. The elastic modulus and hardness of WAW after consolidation with PEG, sucralose and trehalose increased, with improvements of 15.3% and 34.8%, 43.9% and 49.5%, 31.9% and 6.4%, respectively, compared to untreated WAW. All three consolidants were found under scanning electron microscopy (SEM) to have filled wood cell lumens and mesopores in cell walls to different extents. ATR-FTIR imaging and thermogravimetric analysis (TGA) results further indicated that consolidants partly penetrated the wood cell walls. PEG was more concentrated near the fiber lumina. In addition, TGA revealed that the relative contents of PEG and trehalose in consolidated archaeological woods were 54.0% and 39.8%, and the maximum decomposition temperature (Td) of consolidated WAW all differed from the untreated WAW, which suggested non-covalent intermolecular interactions were probably presented between consolidants and WAW cell wall components.

Trehalose-6-phosphate phosphatases are involved in trehalose synthesis and metamorphosis in Bactrocera minax.

Trehalose is the principal sugar circulating in the hemolymph of insects, and trehalose synthesis is catalyzed by trehalose-6-phosphate synthase (TPS) and trehalose-6-phosphate phosphatase (TPP). Insect TPS is a fused enzyme containing both TPS domain and TPP domain. Thus, many insects do not possess TPP genes as TPSs have replaced the function of TPPs. However, TPPs are widely distributed across the dipteran insects, while the roles they play remain largely unknown. In this study, 3 TPP genes from notorious dipteran pest Bactrocera minax (BmiTPPB, BmiTPPC1, and BmiTPPC2) were identified and characterized. The different temporal-spatial expression patterns of 3 BmiTPPs implied that they exert different functions in B. minax. Recombinant BmiTPPs were heterologously expressed in yeast cells, and all purified proteins exhibited enzymatic activities, despite the remarkable disparity in performance between BmiTPPB and BmiTPPCs. RNA interference revealed that all BmiTPPs were successfully downregulated after double-stranded RNA injection, leading to decreased trehalose content and increased glucose content. Also, suppression of BmiTPPs significantly affected expression of downstream genes and increased the mortality and malformation rate. Collectively, these results indicated that all 3 BmiTPPs in B. minax are involved in trehalose synthesis and metamorphosis. Thus, these genes could be evaluated as insecticidal targets for managing B. minax, and even for other dipteran pests.

Effect of Tachinid Parasitoid Exorista japonica on the Larval Development and Pupation of the Host Silkworm Bombyx mori.

The Tachinidae are natural enemies of many lepidopteran and coleopteran pests of crops, forests, and fruits. However, host-tachinid parasitoid interactions have been largely unexplored. In this study, we investigated the effects of tachinids on host biological traits, using Exorista japonica, a generalist parasitoid, and the silkworm Bombyx mori, its lepidopteran host, as models. We observed that E. japonica parasitoidism did not affect silkworm larval body weight gain and cocooning rate, whereas they caused shortened duration of molting from the final instar to the pupal stage, abnormal molting from larval to pupal stages, and a subsequent decrease in host emergence rate. Moreover, a decrease in juvenile hormone (JH) titer and an increase in 20-hydroxyecdysone (20E) titer in the hemolymph of parasitized silkworms occurred. The transcription of JH and 20E responsive genes was downregulated in mature parasitized hosts, but upregulated in parasitized prepupae while Fushi tarazu factor 1 (Ftz-f1), a nuclear receptor essential in larval ecdysis, showed dramatically reduced expression in parasitized hosts at both the mature and prepupal stages. Moreover, the transcriptional levels of BmFtz-f1 and its downstream target genes encoding cuticle proteins were downregulated in epidermis of parasitized hosts. Meanwhile, the content of trehalose was decreased in the hemolymph, while chitin content in the epidermis was increased in parasitized silkworm prepupae. These data reveal that the host may fine-tune JH and 20E synthesis to shorten developmental duration to combat established E. japonica infestation, while E. japonica silences BmFtz-f1 transcription to inhibit host pupation. This discovery highlights the novel target mechanism of tachinid parasitoids and provides new clues to host/tachinid parasitoid relationships.

Exogenous GABA improves the antioxidant and anti-aging ability of silkworm (Bombyx mori)

Silkworm (Bombyx mori) was used to explore the anti-aging ability of Gamma-aminobutyric acid (GABA) and its potential mechanism. 0.086∼8.6 mM GABA solutions were sprayed on mulberry leaves to raise silkworms. The results showed that GABA increased the fecundity of adult silkworms. And in the larva silkworms on the 3th day of the 5th instar, GABA significantly reduced the trehalose content in the hemolymph, the triglycerides and glycogen levels in the fat body, while sharply increased the NAD+/NADH level in the fat body. GABA significantly increased the GSH content and activities of SOD and CAT, while reduced the level of MDA. Furthermore, GABA reduced the mRNA expression of BmRpd3, Bmchico and BmAkh2, while increased the mRNA expression of BmAMPK. In summary, GABA has anti-aging potential by playing roles in energy homeostasis, reducing carbohydrate and lipid level, increasing anti-oxidative capacity, and regulating mRNA expression of longevity-related genes.

Trehalose provisioning in Daphnia resting stages reflects local adaptation to the harshness of diapause conditions.

Environmental fluctuations often select for adaptations such as diapause states, allowing species to outlive harsh conditions. The natural sugar trehalose which provides both cryo- and desiccation-protection, has been found in diapause stages of diverse taxa. Here, we hypothesize that trehalose deposition in resting stages is a locally adapted trait, with higher concentrations produced in harsher habitats. We used resting stages, produced under standardized conditions, by 37 genotypes of Daphnia magna collected from Western Palaearctic habitats varying in their propensity to dry in summer and freeze in winter. Resting eggs produced by D. magna from populations from summer-dry habitats showed significantly higher trehalose than those from summer-wet habitats, suggesting that trehalose has a protective function during desiccation. By contrast, winter-freezing did not explain variation in trehalose content. Adaptations to droughts are important, as summer dryness of water bodies is foreseen to increase with ongoing climate change.

The Photosynthetic Efficiency and Carbohydrates Responses of Six Edamame (Glycine max. L. Merrill) Cultivars under Drought Stress.

Vegetable-type soybean, also known as edamame, was recently introduced to South Africa. However, there is lack of information on its responses to drought. The aim of this study was to investigate the photosynthetic efficiency and carbohydrates responses of six edamame cultivars under drought stress. Photosynthetic efficiency parameters, including chlorophyll fluorescence and stomatal conductance, were determined using non-invasive methods, while pigments were quantified spectrophotometrically. Non-structural carbohydrates were quantified using Megazyme kits. Structural carbohydrates were determined using Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Drought stress significantly increased the Fv/Fm and PIabs of AGS429 and UVE17 at pod filling stage. Chlorophyll-a, which was most sensitive to drought, was significantly reduced in AGS429 and UVE17, but chlorophyll-b was relatively stable in all cultivars, except UVE17, which showed a significant decline at flowering stage. AGS354 and AGS429 also showed reduced chlorophyll-b at pod filling. UVE17 showed a significant reduction in carotenoid content and a substantial reduction in stomatal conductance during pod filling. Drought stress during pod filling resulted in a significant increase in the contents of trehalose, sucrose and starch, but glucose was decreased. Chlorophyll-a positively correlated with starch. The FTIR and XRD results suggest that the cell wall of UVE14, followed by UVE8 and AGS429, was the most intact during drought stress. It was concluded that carotenoids, stomatal conductance, starch and hemicellulose could be used as physiological/biochemical indicators of drought tolerance in edamame. This information expands our knowledge of the drought defense responses in edamame, and it is essential for the physiological and biochemical screening of drought tolerance.

Effect of Trehalose on the Physicochemical Properties of Freeze-Dried Powder of Royal Jelly of Northeastern Black Bee

Trehalose is known for its effect of improving the stability of freeze-dried foods. In this work, vacuum freeze-drying (VFD) technology was employed to prepare northeast black bee royal jelly into lyophilized powder and a novel method mixing trehalose into royal jelly is successfully developed to enhance the free radical scavenging ability and the nutrition stability of royal jelly lyophilized powder. The effects of different trehalose content (0, 0.1, 0.3, 0.5, 0.7 and 0.9 wt.%) on the physicochemical properties of lyophilized royal jelly powder were studied. With systematic analysis, it was found that the incorporation of suitable trehalose content in lyophilized royal jelly powder can reduce the loss of the protein, total sugar, total flavone content during the VFD process and enhance the total phenolic antioxidant capacity, solubility, angle of repose, and bulk density of the royal jelly powder. Finally, lyophilized royal jelly with 0.5 wt.% trehalose is selected as the suitable addition content which exhibits the best radical scavenging ability as well as the lowest hygroscopicity. From the perspective of sensory evaluation, all royal jelly lyophilized powders with trehalose are acceptable.

Detrimental Impact of λ-Cyhalothrin on the Biocontrol Efficacy of Eocanthecona furcellata by Affecting Global Transcriptome and Predatory Behavior.

Whether and how insecticide exposure will affect the biological control efficacy of predatory arthropods is critical in insecticide toxicology research but largely unexplored. In the current study, reduced biocontrol efficacy was observed in a predatory stink bug─Eocanthecona furcellata─after insecticide application in the field. Thus, we constructed a comparative transcriptome analysis and identified a total of 4364 upregulated and 1043 down regulated differentially expressed genes following the sublethal exposure of λ-cyhalothrin. The reduced juvenile hormone (JH) titer and increased trehalose content were observed. The predation capacity and theoretical maximum predation of predators were decreased by 31.08 and 48.90% in response to λ-cyhalothrin, respectively. Furthermore, JH supplementation after λ-cyhalothrin treatment could significantly stimulate trehalase and detoxification enzyme activities, as well as restore the predatory ability of E. furcellata. Our results help to understand the toxicological mechanism of predatory stink bug species in responding to insecticides, benefit predators' ecological services, and optimize the insecticide selection.

Trehalose promotes the formation of Lanzhou lily bulblets by increasing carbohydrate content

ABSTRACT Recent studies have shown that trehalose plays an important and pervasive role in plants, which actively regulates seed germination, flowering, and stress tolerance. However, whether trehalose promotes bulblet formation in Lanzhou lily (Lilium davidii) scale cutting propagation has not been reported. In the current study, the regulatory roles of trehalose during the formation of bulblets in lily-scale cutting were investigated. The results show that trehalose significantly increased the number and diameter of bulblets with an optimal concentration at 50 mM. Moreover, trehalose increased the content of sucrose, starch, soluble sugar and endogenous trehalose in the scales and bulblets. These results indicate that trehalose might promote the formation of Lanzhou lily bulblets by increasing the carbohydrate content in the scales. Further, trehalose improved trehalose 6-phosphate synthase (TPS) and ADP glucose pyrophosphorylase (AGP) activity, reduced Sucrose synthase (SuSy) activity in scales, up-regulated SSS1, SBE, AGP1, TPS6, TPS7, TPS9 expression level in scales on day 50, and down-regulated SuSy1 and INV2 expression level in scales. Therefore, trehalose might increase carbohydrates content in scales and bulblets by regulating the activity and gene expression of key enzymes in carbohydrate synthesis and hydrolysis pathways, thereby promoting bulblet formation in Lanzhou lily-scale cutting.

Membrane-permeable trehalose improves the freezing ability and developmental competence of in-vitro matured feline oocytes

Oocytes are highly sensitive to cryopreservation, which frequently results in an irreversible loss of developmental competence. We examined the effect of membrane-permeable trehalose on the freezing ability of feline oocytes matured in vitro. In Experiment 1, intracellular trehalose (trehalose hexaacetate; Tre-(OAc)6) was synthesized from trehalose precursor and subjected to spectroscopic characterization. The membrane permeability of the Tre-(OAc)6 was investigated by incubating oocytes with different concentrations of Tre-(OAc)6 (3, 15, and 30 mM). Optimum concentration and the toxicity of Tre-(OAc)6 were assessed in Experiment 2. The effects of Tre-(OAc)6 on freezing ability in terms of apoptotic gene expression and developmental competence of in-vitro matured oocytes were examined in Experiments 3 and 4, respectively. The Tre-(OAc)6 permeated into the ooplasm of cat oocytes in a dose- and time-dependent manner. The highest concentration of intracellular trehalose was detected when the oocytes were incubated for 24 h with 30 mM Tre-(OAc)6. For the toxicity test, incubation of oocytes with 3 mM Tre-(OAc)6 for 24 h did not affect maturation rate and embryo development. However, high doses of Tre-(OAc)6 (15 and 30 mM) significantly reduced maturation and fertilization rates (p < 0.05). In addition, frozen-thawed oocytes treated with 3 mM Tre-(OAc)6 significantly upregulated anti-apoptotic (BCL-2) gene expression compared with the control (0 mM) and other Tre-(OAc)6 concentrations (15 and 30 mM). Oocyte maturation in the presence of 3 mM Tre-(OAc)6 prior to cryopreservation significantly improved oocyte developmental competence in terms of cleavage and blastocyst rates when compared with the control group (p < 0.05). Our results lead us to infer that increasing the levels of intracellular trehalose by Tre-(OAc)6 during oocyte maturation improves the freezing ability of feline oocytes, albeit at specific concentrations.

A Simulation Study on Model-Based Optimization of Intracellular Trehalose Accumulation in Saccharomyces cerevisiae Fed-Batch Cultures

Trehalose is a reserve carbohydrate, which occurs naturally in yeast and acts as a stress protectant for cells. Due to its features, trehalose is used in many industries (food, biopharmaceuticals, cosmetics). Its production/accumulation may be triggered and enhanced by the culture operating conditions, among which the feed flow rate and the start of the starvation period play the most important role. This paper presents a simulation study based on a novel model validated with experimental data, highlighting the interplay between trehalose maximization and biomass maximization. Several single-objective and multi-objective constrained optimization problems are solved using the control vector parameterization approach. It is shown that maximizing either the trehalose concentration or the biomass amount leads to solutions which are not appealing in practice. The best solution is obtained by maximizing trehalose concentration with a lower bound on the biomass amount. A comparison of the optimal solution to experimental data reveals that, although approximately the same amount of biomass can be obtained with different feeding profiles and starvation times, the maximization of trehalose concentration requires feeding most of the culture medium in the first part of the experiment while starting the nitrogen starvation at an early stage.

Melatonin regulates lily bulblet development through the &lt;i&gt;LoBPM3&lt;/i&gt;-&lt;i&gt;LoRAV&lt;/i&gt; module

Melatonin regulates lily bulblet development; however, the key interactions have not yet been determined. In this study, we found that adding 20 μM melatonin to the growth medium increased the bulblet circumference and the trehalose and starch content. Moreover, the expression of numerous genes involved in cell proliferation and carbohydrate accumulation were upregulated. Further analysis showed that melatonin downregulated the expression of <italic>LoRAV</italic> and upregulated the expression of <italic>LoBPM3</italic> at an early stage. Cloning and bioinformatics analysis showed that<italic> LoRAV</italic> is 1056 bp in length and encodes a protein with two structural domains, namely, AP2 and B3; the encoded protein is localized to the nucleus and has no self-activation activity, and this protein interacts with LoBPM3. The expression of <italic>LoTCP4</italic> and <italic>LoAMY</italic> was upregulated, while the expression of<italic> LoAGPase</italic>, <italic>LoCYCB2-1</italic>, and <italic>LoPCNA</italic> was inhibited when <italic>LoRAV</italic> was transiently overexpressed. However, the trends in the expression of the genes mentioned above, except <italic>LoAGPase</italic> and <italic>LoAMY,</italic> were reversed when <italic>LoRAV</italic>-OE was treated with melatonin. Interestingly, the expression of <italic>LoRAV</italic>, <italic>LoTCP4</italic> and <italic>LoAMY</italic> was inhibited, and the expression of <italic>LoCYCB2-1</italic> was upregulated by transient overexpression of <italic>LoBPM3</italic>, but the expression of <italic>LoBPM3</italic> was not regulated by <italic>LoRAV</italic> overexpression. Based on these data, we suggest that melatonin promoted bulb development, which was partly associated with regulation of the LoBPM3-LoRAV module; thus, <italic>LoRAV</italic> negatively regulates cell proliferation of bulblets, and <italic>LoBPM3</italic> is located upstream of <italic>LoRAV</italic> and attenuates its expression.

Cloning, expression and function analysis of trehalose-6-phosphate synthase gene from Marsupenaeus japonicu.

Trehalose is an important disaccharide that plays an important role in extreme environmental conditions. Trehalose-6-phosphate synthase (TPS) gene is the key gene for trehalose synthesis in Marsupenaeus japonicus. In this study, a TPS gene was isolated and characterized from M. japonicus. The full-length cDNA of TPS gene of M. japonicus (MjTPS) was 3308bp, encoding 844 amino acids. The protein of the deduced MjTPS contained a glycol_transf_20 domain and a trehalose_PPase domain. The mRNA expression level of MjTPS was the highest in hepatopancreas. The further analysis found that MjTPS gene expression was up-regulated in a short time under low-salinity and high-nitrite stress, indicating that MjTPS gene had certain resistance to low-salinity and high-nitrite stress. Compared with the control group, both the expression of MjTPS and the trehalose content significantly decreased from 3h to 24h after MjTPS gene interference,. After RNAi, the mortality of M. japonicus increased, the expression level of MjTPS and the synthesis of downstream products decreased under low-salinity and high-nitrite stress, and what's more, the expression of immune genes PMO25, ERP, CD, HSP90, HSP70, HSP60, HMC and CLEC2 were significantly changed, implying that MjTPS might be participated in the immune response of M. japonicus. In addition, MjTPS gene silencing could affect the expression of CHI1 and CHS, suggesting that MjTPS might be involved in molting behavior of M. japonicus. These results provide new information for further studying the function of trehalose-6-phosphate synthase in shrimp.

Facilitating trehalose entry into hRBCs at 4 °C by alkylated ε-poly(L-lysine) for glycerol-free cryopreservation.

Currently, glycerol is a conventional cryoprotectant of human red blood cells (hRBCs), but the time-consuming thawing and deglycerolization processes are essential before transfusion. Much of the research up to now has been conducted on the delivery of impermeable trehalose to hRBCs at 37 °C, but the cryoprotective effect of trehalose and deterioration of cells still remain challenging. Encouraged by the interaction of hydrophobic or cationic groups on cell membranes and osmotic stabilization, herein, we propose a novel cryopreservation system to facilitate trehalose entry into hRBCs at 4 °C and pH 7.4. High intracellular trehalose contents and cryosurvival of hRBCs were achieved with small function variations via the assistance of self-assembled nanoparticles of alkylated ε-poly(L-lysine) (ε-PL) along with poly(vinyl pyrrolidone) (PVP). The effect of amphipathic alkylated ε-PL with various alkyl chains and grafting ratios on membrane perturbation with protection of PVP was systematically investigated. Overall, by the combination of alkylated ε-PL and PVP, the intracellular trehalose could be enhanced to 109.7 ± 6.1 mM and subsequently hRBC cryosurvival reached 91.7 ± 5.5%, significantly higher than those containing trehalose only, 11.9 ± 1.1 mM and 50.0 ± 2.1%, respectively. It was observed that the biocompatible trehalose-loading system could benefit glycerol-free cryopreservation of hRBCs and also provide a feasible way for impermeable biomacromolecule delivery.

Macroscopic Modeling of Intracellular Trehalose Concentration in Saccharomyces cerevisiae Fed-batch Cultures

This paper describes the extension of a baker's yeast growth model to account for the intracellular trehalose storage and mobilization. Trehalose is a reserve carbohydrate that is accumulated and converted back to intracellular glucose when the yeast cells face certain stresses. This is modeled by a new macroscopic reaction, which is coupled to an existing macroscopic reaction scheme describing the coordinated uptake of glucose and ammonium by the yeast cells. The dynamics of the trehalose concentration is described by a delay differential equation as the available experimental data used to fit the model exhibits a time-delayed correlation between trehalose storage and glucose uptake as well as a time-delayed correlation between trehalose mobilization and ethanol respiration phases. The proposed extension contains 6 parameters of which 5 are estimated via nonlinear least squares identification. The proposed model predicts accurately the dynamics of trehalose storage and mobilization and can be used to optimize the intracellular trehalose accumulation in Saccharomyces cerevisiae, which is valuable for obtaining reinforced yeast cells, able to better withstand drying operations.

Synergistic interaction between ABA and IAA due to moderate soil drying promotes grain filling of inferior spikelets in rice.

Poor grain filling of inferior spikelets is becoming a severe problem in some super rice varieties with large panicles. Moderate soil drying (MD) after pollination has been proven to be a practical strategy to promote grain filling. However, the molecular mechanisms underlying this phenomenon remain largely unexplored. Here, transcriptomic analysis of the most active grain filling stage revealed that both starch metabolism and phytohormone signaling were significantly promoted by MD treatment, accompanied by increased enzyme activities of starch synthesis and elevated abscisic acid (ABA) and indole-3-acetic acid (IAA) content in the inferior spikelet. Moreover, the IAA biosynthesis genes OsYUC11 and OsTAR2 were upregulated, while OsIAA29 and OsIAA24, which encode two repressors of auxin signaling, were downregulated by MD, implying a regulation of both IAA biosynthesis and auxin signal transduction in the inferior spikelet by MD. A notable improvement in grain filling of the inferior spikelet was found in the aba8ox2 mutant, which is mutated in an ABA catabolism gene. In contrast, overexpression of OsABA8ox2 significantly reduced grain filling. Interestingly, not only the IAA content, but also the expression of IAA biosynthesis and auxin-responsive genes displayed a similar trend to that in the inferior spikelet under MD. In addition, several OsTPP genes were downregulated in the inferior spikelets of both MD/ABA-treated wild-type plants and the aba8ox2 mutant, resulting in lower trehalose content and higher levels of -6-phosphate (T6P), thereby increasing the expression of OsTAR2, a target of T6P. Taken together, our results suggest that the synergistic interaction of ABA-mediated accumulation of IAA promotes grain filling of inferior spikelets under MD.

Effects of different phosphorus-free water-retaining agents on the quality of frozen tilapia fillets.

Tilapia is an economically important fish worldwide, but its quality is affected by storage practices. To improve the quality of tilapia fillets during frozen storage, we examined the effect of pretreatment with various combinations of different concentrations of trehalose, potassium bicarbonate, and chitosan. Following pretreatment, we analyzed the tilapia fillets using quality indicators, including soaking weight gain, coating weight gain, water‐holding capacity, thawing loss, pH, Ca2+‐ATPase activity, and texture characteristics. Water distribution was analyzed using low‐field nuclear magnetic resonance and the optimal combination of water‐retaining agents was obtained using an L8(27) orthogonal experiment. The results showed that trehalose, potassium bicarbonate, and chitosan improved fillet quality at pretreatment concentrations of 5%–8%, 1.0%, and 0.5%, respectively. The optimal combination was 4% trehalose plus 1.2% potassium bicarbonate plus 0.2% chitosan. The Ca2+‐ATPase activity and mastication property of the frozen fillets that were pretreated with the optimized formulation were 1.39 μmol Pi/mg protein·h and 8.55 mJ, respectively, which were 43.3% and 80.0% greater, respectively, than that of the control group. Using a suitable concentration and combination of water‐retaining agents cannot only lock‐in the internal water content of frozen tilapia fillets but also improve their quality during frozen storage. These results can inform practical storage practices of similar aquatic products.