Trehalose Content Research Articles

Diapause-induced shift in the content of major carbohydrates in Chilo partellus (Swinhoe).

Although several aspects like diapause determining factors, population structure, reproductive physiology, and genetics of diapause have been investigated, there is no clarity on carbohydrate energetics during larval diapause in Chilo partellus (Swinhoe). Present studies revealed significant variation between the nondiapausing and diapausing C. partellus for total carbohydrates, glycogen, sorbitol, and trehalose contents in different body parts, life stages, and for body parts × life stages interaction. Total carbohydrate content started declining, while sorbitol and trehalose increased in all the body parts as the C. partellus larvae progressed from prediapausing to diapausing state. However, glycogen content spiked in all the body parts at prediapausing stage, which then declined during diapause. Among the body parts, total carbohydrate content was significantly greater in the hemolymph as compared to other body parts of both larvae and pupae of C. partellus. Glycogen content was significantly greater in the larval fat bodies and pupal hemolymph as compared to their other body parts. In diapausing larvae, sorbitol and trehalose were greater in the integument than in other body parts. Furthermore, there was spike in trehalose and decrease in sorbitol in all the body parts of pupae from diapausing than those from nondiapausing larvae. These findings suggest that the diapause alterate and/or fluctuate major carbohydrates in different body parts of both larvae and pupae of C. partellus. This information will be helpful in better understanding the diapause energetics and overwintering metabolic cryoprotection in insects.

Comparative effectiveness of deltamethrin, imidacloprid and emamectin benzoate alone and in binary blends to control Trogoderma granarium: Effect on macronutrients

Trogoderma granarium Everts (Insecta, Dermestidae) severely attacks a variety of stored commodities, and its control has been achieved by conventional insecticides. However, unplanned use of insecticides leads towards emergence of resistance as well as health and environment damage. Previous studies reported insecticidal efficacy of deltamethrin (DL), emamectin benzoate (EB) and imidacloprid (IM) individually but lacking efficacy of mixtures against T. granarium. The study presented here was aimed at investigating the susceptibility of field collected Mandi Bahaud Din (MBD) population (14 years DL exposure history) and a DL susceptible LAB-S population (not exposed to insecticides since 2001) against DL, EB and IM individually and in binary mixtures (DL:EB, DL:IM and EB:IM) at different ratio (1:1, 1:2, 1:3, 2:1 and 3:1). The MBD strain showed greater susceptibility against IM and EB (LC50 473.09 and 556.4 ppm) respectively, but decreased susceptibility (LC50 808.67 ppm) against DL indicating DL resistance. The LC50 values were 251.62, 307.15 and 369.73 ppm against DL, IM and EB, respectively in LAB-S strain. All binary mixtures exhibited synergistic interactions against MBD strain and EB:IM mixture (3:1) was found the most effective (RTU 3.93) among all the tested combinations. In contrast, EB:IM mixture showed antagonistic interactions (1:1, 1:2, 1:3, 2:1) but synergistic interactions were achieved by increasing EB concentration (3:1, RTU 1.23) in mixture against LAB-S strain. However, DL:EB was more effective (RTU 2.1) against LAB-S strain among all the tested combinations. The toxic effect of LC20 of most effective mixture on macronutrients was also investigated. A significant reduction in contents of trehalose, total protein, soluble protein, total lipids and glycogen while an increase in glucose and free amino acids was observed in both strains in comparison with their respective unexposed control. It is concluded that binary mixture reduces the net quantity of conventional insecticides, thus offering more effective approach to control T. granarium.

Effects and molecular mechanism of sugar transporter ESA_RS15745 on desiccation resistance, motility, and biofilm formation of Cronobacter sakazakii.

Cronobacter sakazakii, an important Gram-negative foodborne pathogen, can cause neonatal meningitis and sepsis with high rates of infection and death. Gene ESA_RS15745 encodes a sugar transporter protein, which is not only essential for osmotic pressure maintenance during bacterial growth and reproduction but also associated with their desiccation tolerance, motility, and biofilm formation. Here, a mutant strain of ESA_RS15745 (ΔESA_RS15745) and the complementation strain (cpESA_RS15745) were constructed using a suicide vector knockout and gene complementation. ΔESA_RS15745 was found to have a decrease in its ability to transport maltose and trehalose and resist desiccation, whereas an increase in the ability of motility and biofilm formation, implying that ESA_RS15745 may positively regulate sugar transport and desiccation tolerance and negatively regulate motility and biofilm formation. To further investigate the molecular mechanisms underlying the function of related genes, RNA-seq was performed to explore the differentially expressed genes in the mutants. RNA-seq results showed the upregulation of 114 genes (mainly including those regulating chemotaxis and flagellar motility) and the downregulation of 22 genes (mainly including those regulating sugar transport). qRT-PCR analysis supported the RNA-seq results and showed that ESA_RS15745 may influence the dehydration tolerance though decreasing the intracellular trehalose content and negatively regulate the motility though the chemotactic signaling pathway. In addition, the biofilm formation of C. sakazakii should also be speculated to negatively regulate by ESA_RS15745 by consuming the extracellular carbohydrates concentration and then downregulating the intracellular cyclic diguanosine monophosphate. This study offers a reference for comprehending the molecular mechanism of gene ESA_RS15745 in C. sakazakii.

Hibernation induced biochemical changes in spotted stem borer <i>Chilo partellus</i>

Spotted stem borer, Chilo partellus (Swinhoe) is one of the most destructive pests of sorghum and maize, and undergoes hibernation during harsh winters. Several aspects of diapause have been studied, however metabolic and biochemical processes underlying hibernation remain poorly understood in C. partellus. Present studies carried out during 2020–22 at ICAR-Indian Agricultural Research Institute, New Delhi deciphered the variations in nutritional biochemicals, digestive and stress enzymes, cryoprotectants in the hibernation and in non-hibernating larvae and pupae of C. partellus. These studies revealed that the total lipids and proteins were significantly greater during pre- hibernation and hibernation, and sugars were greater in non-hibernation larvae. Glycogen content was greater in pre- hibernation, and sorbitol, trehalose and glucitol contents consistently increased from pre-hibernation to hibernation stages in comparison to non-hibernation larvae of C. partellus. Total sugar and sorbitol contents decreased, while total protein, trehalose and glucitol increased, in post-hibernation than the non-hibernation pupae of C. partellus. Activities of ascorbic acid, lipid peroxidation, total antioxidant, catalase and superoxide dismutase were significantly greater during hibernation followed by pre-hibernation as compared to non-hibernation larvae, while the reverse was the case with protease activity. Ascorbic acid, lipid peroxidation, total antioxidant and catalase activities were greater in post-hibernation as compared to non-hibernation pupae of C. partellus. However, glutathione S-transferase activity was greater in the non-hibernation larvae and pupae than the hibernation larvae and post-hibernation pupae of C. partellus. These findings can be useful to design newer management strategies keeping in view the weak links like the state of nutritional metabolism and oxidative stress tolerance due to diapause in C. partellus.

Phenolic content and antioxidant activity in Lentinula edodes grown on eucalyptus biomass

Objective. To determine whether Lentinula edodes (L edodes) cultured on eucalyptus chips in the Ecuadorian highland generates antioxidant metabolites and anti-inflammatory effects.
 Methods. Total phenolic content was determined by the Folin-Ciocalteu reaction, the in vitro antioxidant activity of L edodes extracts was evaluated by the DPPH method and the in vivo anti-inflammatory activity was studied in mice. The chemical composition was studied by phytochemical screening and gas chromatography/mass spectrometry (GC/MS).
 Results. Total phenols were higher in extracts with increasingly high-water content. The antioxidant activity was robust and significantly strong in these extracts, suggesting the active metabolites are water-soluble. The anti-inflammation activity was significant in aqueous extracts only. Phytochemical screening indicated an overall similar composition to the literature reported earlier. GC/MS detected galactitol, trehalose, xylitol, phosphoric acid and octadecanoic acid among the most abundant metabolites.
 Conclusions. Cultivation on eucalyptus biomass at the Ecuadorian highlands retains the overall chemical composition, the phenolic content, antioxidant levels, and the in vivo anti-inflammatory activity of L edodes. The 11.3% content of trehalose observed is interesting for its capacity to control cellular stress damage.
 Key Words: inflammation, antioxidants, phenols, shiitake, Lentinula, phytotherapeutics

Regulatory effect of trehalose metabolism on chitin synthesis in Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) as determined using RNAi

Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) is an important pest of crops that causes huge losses to grain production. Trehalose plays an important regulatory role in chitin synthesis. In this study, the mRNA expression of the trehalose synthase (TPS), soluble trehalase (TRE1), and membrane-bound trehalase (TRE2) genes in S. frugiperda were silenced by RNAi to reveal the mechanism by which trehalose metabolism regulates chitin synthesis. The results showed that the survival rate of S. frugiperda at different developmental stages decreased in varying degrees following RNAi, and abnormal phenotypes were detected. TRE1 activity was extremely significantly inhibited after dsTRE1 and dsTRE2 injection, and TRE2 activity was extremely significantly inhibited after dsTPS and dsTRE2 injection. After silencing different trehalose metabolism-related regulatory genes, the trehalose content increased, whereas the glucose content decreased. Chitin synthase A (CHSA) gene was upregulated at 24 h after dsTPS and dsTRE1 injection. CHSA expression was significantly inhibited at 48 h after dsTRE1 injection. Chitin synthase B (CHSB) gene expression was significantly higher at 24 h after dsTRE1 injection. Furthermore, CHSB expression was significantly inhibited at 48 h after dsTPS, dsTRE1, or dsTRE2 injection. RNAi of TRE1 or TRE2 led to a significant decrease in chitin content. The results suggested that inhibiting the mRNA expression of genes related to trehalose metabolism in S. frugiperda could disrupt normal trehalose metabolism, thereby regulating the mRNA expression of downstream chitin synthase genes and further affecting chitin synthesis.

Physiological and Transcriptomic Analysis Reveals That Melatonin Alleviates Aluminum Toxicity in Alfalfa (Medicago sativa L.).

Aluminum (Al) toxicity is the most common factor limiting the growth of alfalfa in acidic soil conditions. Melatonin (MT), a significant pleiotropic molecule present in both plants and animals, has shown promise in mitigating Al toxicity in various plant species. This study aims to elucidate the underlying mechanism by which melatonin alleviates Al toxicity in alfalfa through a combined physiological and transcriptomic analysis. The results reveal that the addition of 5 μM melatonin significantly increased alfalfa root length by 48% and fresh weight by 45.4% compared to aluminum treatment alone. Moreover, the 5 μM melatonin application partially restored the enlarged and irregular cell shape induced by aluminum treatment, resulting in a relatively compact arrangement of alfalfa root cells. Moreover, MT application reduces Al accumulation in alfalfa roots and shoots by 28.6% and 27.6%, respectively. Additionally, MT plays a crucial role in scavenging Al-induced excess H2O2 by enhancing the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), consequently reducing malondialdehyde (MDA) levels. More interestingly, the RNA-seq results reveal that MT application significantly upregulates the expression of xyloglucan endotransglucosylase/hydrolase (XTH) and carbon metabolism-related genes, including those involved in the glycolysis process, as well as sucrose and starch metabolism, suggesting that MT application may mitigate Al toxicity by facilitating the binding of Al to the cell walls, thereby reducing intracellular Al accumulation, and improving respiration and the content of sucrose and trehalose. Taken together, our study demonstrates that MT alleviates Al toxicity in alfalfa by reducing Al accumulation and restoring redox homeostasis. These RNA-seq results suggest that the alleviation of Al toxicity by MT may occur through its influence on cell wall composition and carbon metabolism. This research advances our understanding of the mechanisms underlying MT's effectiveness in mitigating Al toxicity, providing a clear direction for our future investigations into the underlying mechanisms by which MT alleviates Al toxicity in alfalfa.

Transcription factor OsMYB30 increases trehalose content to inhibit α-amylase and seed germination at low temperature.

Low-temperature germination (LTG) is an important agronomic trait for direct-seeding cultivation of rice (Oryza sativa). Both OsMYB30 and OsTPP1 regulate the cold stress response in rice, but the function of OsMYB30 and OsTPP1 in regulating LTG and the underlying molecular mechanism remains unknown. Employing transcriptomics and functional studies revealed a sugar signaling pathway that regulates seed germination in response to low temperature (LT). Expression of OsMYB30 and OsTPP1 was induced by LT during seed germination, and overexpressing either OsMYB30 or OsTPP1 delayed seed germination and increased sensitivity to LT during seed germination. Transcriptomics and qPCR revealed that expression of OsTPP1 was upregulated in OsMYB30-overexpressing lines but downregulated in OsMYB30-knockout lines. In vitro and in vivo experiments revealed that OsMYB30 bound to the promoter of OsTPP1 and regulated the abundance of OsTPP1 transcripts. Overaccumulation of trehalose (Tre) was found in both OsMYB30- and OsTPP1-overexpressing lines, resulting in inhibition of α-amylase 1a (OsAMY1a) gene during seed germination. Both LT and exogenous Tre treatments suppressed the expression of OsAMY1a, and the osamy1a mutant was not sensitive to exogenous Tre during seed germination. Overall, we concluded that OsMYB30 expression was induced by LT to activate the expression of OsTPP1 and increase Tre content, which thus inhibited α-amylase activity and seed germination. This study identified a phytohormone-independent pathway that integrates environmental cues with internal factors to control seed germination.

Explanation and prediction for the product of trehalose dihydrate selective dehydration process using mid-frequency Raman difference spectra

Explanation and prediction for the product of trehalose dihydrate dehydration process was realized in this work. β form is the thermodynamic dehydration product of trehalose dihydrate. And α form is the kinetic dehydration product of trehalose dihydrate, which was analyzed by low-frequency Raman spectra, mid-frequency Raman difference spectra and IR difference spectra, and the analysis results confirmed that the crystal structure of trehalose dihydrate and α form are similar. The selective dehydration process from trehalose dihydrate to α form is due to their similar short-range orders. Amorphous trehalose is the uncontrollable dehydration product of trehalose dihydrate due to the collapse of water channels. The dehydration product of trehalose dihydrate by freeze-drying was a mixture of α form and amorphous phase, and the content of amorphous trehalose in the freeze-drying product increases with the decrease of the particle size of dihydrate. Study on the dehydration principle of organic hydrates will guide the preparation, storage and desolvation of drugs and foods.

Trehalose-6-Phosphate Synthase Contributes to Rapid Cold Hardening in the Invasive Insect Lissorhoptrus oryzophilus (Coleoptera: Curculionidae) by Regulating Trehalose Metabolism.

Rapid cold hardening (RCH) is known to rapidly enhance the cold tolerance of insects. Trehalose has been demonstrated to be a cryoprotectant in Lissorhoptrus oryzophilus, an important invasive pest of rice in China. Trehalose synthesis mainly occurs through the Trehalose-6-phosphate synthase (TPS)/trehalose-6-phosphate phosphatase (TPP) pathway in insects. In this study, the TPS gene from L. oryzophilus (LoTPS) was cloned and characterized for the first time. Its expression and trehalose content changes elicited by RCH were investigated. Our results revealed that RCH not only increased the survival rate of adults but also upregulated the expression level of LoTPS and increased the trehalose content under low temperature. We hypothesized that upregulated LoTPS promoted trehalose synthesis and accumulation to protect adults from low-temperature damage. To further verify the function of the LoTPS gene, we employed RNA interference (RNAi) technology. Our findings showed that RCH efficiency disappeared and the survival rate did not increase when the adults were fed dsRNA of LoTPS. Additionally, inhibiting LoTPS expression resulted in no significant difference in trehalose content between the RCH and non-RCH treatments. Furthermore, the expression patterns of trehalose transporter (TRET) and trehalase (TRE) were also affected. Collectively, these results indicate the critical role of LoTPS in L. oryzophilus cold resistance after RCH induction. LoTPS can enhance survival ability by regulating trehalose metabolism. These findings contribute to further understanding the role of TPS in insect cold resistance and the invasiveness of L. oryzophilus. Moreover, RNAi of LoTPS opens up possibilities for novel control strategies against L. oryzophilus in the future.

Behavioral and Physiological Adaptation to Soil Moisture in the Overwintering Larvae of the Rice Stem Borer in the Subtropics

Diapausing larvae of the rice stem borer, Chilo suppressalis Walker, overwinter in rice stubble. During overwintering, the larvae may move to sites with suitable moisture and undergo physiological changes to prepare for the declining temperature. This study measured the behavioral and physiological adaptation to soil moisture (25%, 50%, and 75% of saturated soil water content) in the diapausing larvae at 30, 60, and 90 days of treatment. The results showed that the diapausing C. suppressalis larvae behaviorally exhibited hygrotaxis and distributed mainly (65%) in the lower part (0–10 cm above the soil level) of the rice stem where the moisture was higher. Physiologically, the insects showed significantly decreased glycogen content and weight whereas increased trehalose content with decreasing soil moisture. In the subtropics where this study was conducted, the supercooling points of the insects were lower than the lowest ambient temperature, and the soil moisture had no significant effects on the cold hardiness (supercooling point) and survival of the diapausing C. suppressalis larvae. The decreased larval weight at low soil moisture may reduce the post-diapause reproductive potential of the larvae, which may open the potential of developing agronomic measures-based management of the overwintering C. suppressalis population.

The limits of stress-tolerance for zooplankton resting stages in freshwater ponds.

In seasonal environments, many organisms evolve strategies such as diapause to survive stressful periods. Understanding the link between habitat stability and diapause strategy can help predict a population's survival in a changing world. Indeed, resting stages may be an important way freshwater organisms can survive periods of drought or freezing, and as the frequency and extent of drought or freezing vary strongly among habitats and are predicted to change with climate change, it raises questions about how organisms cope with, and survive, environmental stress. Using Daphnia magna as a model system, we tested the ability of resting stages from different populations to cope with stress during diapause. The combination of elevated temperatures and wet conditions during diapause shows to prevent hatching altogether. In contrast, hatching is relatively higher after a dry and warm diapause, but declines with rising temperatures, while time to hatch increases. Resting stages produced by populations from summer-dry habitats perform slightly, but consistently, better at higher temperatures and dryness, supporting the local adaptation hypothesis. A higher trehalose content in resting eggs from summer-dry habitat might explain such pattern. Considering that temperatures and summer droughts are projected to increase in upcoming years, it is fundamental to know how resting stages resist stressful conditions so as to predict and protect the ecological functioning of freshwater ecosystems.

Effects of exogenous trehalose on filling characteristics and sugar component content of wheat under high temperature stress during the filling period.

Taking the heat-sensitive wheat variety 'Fanmai 5' (FM5) and the heat-tolerant variety 'Huaimai 33' (HM33), which were screened out in the previous experiments, as experimental materials, we conducted a field experiment with passive heat-enhancing shelters to simulate post-flowering high-temperature environment (average temperature increase of 5.13 ℃) during 2021-2022. During the filling period, we analyzed the effects of exogenous trehalose (10, 15 and 20 mmol·L-1) on the filling characteristics and sugar fraction under high temperature, with no spraying at ordinary temperature as control (CK). The results showed that treating without spraying exogenous trehalose at high temperature (H) significantly reduced wheat grain yield and grain weight during the filling period, and spraying exogenous trehalose alleviated the reduction of grain yield and grain weight at the filling stage under high temperature stress. Compared with the H treatment, grain yield and grain weight of HM33 and FM5 wheat varie-ties increased by 3.5%, 6.7% and 4.2%, 5.4%, respectively. High temperature stress significantly increased the trehalose content and trehalase (THL) activity in flag leaves of both wheat varieties, and decreased the fructose and glucose contents. Spraying exogenous trehalose increased the contents of trehalose, fructose, and glucose in flag leaves, and decreased the trehalase activity in flag leaves compared with H treatment, which could improve the glucose metabolism capacity of wheat at filling stage. The increasing effect of FM5 was higher than that of HM33. High temperature stress significantly reduced starch content of flag leaves and grains, while spraying exogenous trehalose alleviated the decrease of starch content of flag leaves and grains under high temperature stress, which was profit able for the substance accumulation of wheat grains under high temperature stress. Under the conditions of this experiment, spraying 15 mmol·L-1 trehalose at flowering stage was the best treatment for the two wheat varieties.

The miRNA–mRNA regulatory networks of the response to NaHCO3 stress in industrial hemp (Cannabis sativa L.)

BackgroundIndustrial hemp is an important industrial crop and has strong resistance to saline-alkaline stress. However, research on the industrial hemp response to NaHCO3 stress is limited. Therefore, the response mechanisms of industrial hemp under NaHCO3 stress were analysed through miRNA–mRNA regulatory networks.ResultsSeedlings of two salt–alkali tolerant and sensitive varieties were cultured in a solution containing 100 mM NaHCO3 and randomly sampled at 0, 6, 12, and 24 h. With prolonged NaHCO3 stress, the seedlings gradually withered, and the contents of jasmonic acid, lignin, trehalose, soluble protein, peroxidase, and superoxide dismutase in the roots increased significantly. The abscisic acid content decreased and then gradually increased. Overall, 18,215 mRNAs and 74 miRNAs were identified as differentially expressed under NaHCO3 stress. The network showed that 230 miRNA–mRNA interactions involved 16 miRNAs and 179 mRNAs, including some key hub novel mRNAs of these crucial pathways. Carbon metabolism, starch, sucrose metabolism, plant hormone signal transduction, and the spliceosome (SPL) were crucial pathways in industrial hemp's response to NaHCO3 stress.ConclusionsIt is speculated that industrial hemp can regulate SPL pathway by upregulating miRNAs such as novel_miR_179 and novel_miR_75, thus affecting starch and sucrose metabolism, plant hormone signal transduction and carbon metabolism and improving key physiological indices such as jasmonic acid content, trehalose content, and peroxidase and superoxide dismutase activities under NaHCO3 stress.

The sensor histidine kinase (SLN1) and acetyl-CoA carboxylase (ACC1) coordinately regulate the response of Neurospora crassa to the springtail Sinella curviseta (Collembola: Entomobryidae) attack.

Understanding the regulatory pathways by which fungi respond to environmental signals through interlinked genes provides insights into the interactions between fungi and insects. The coordinated optimization of the regulatory networks is necessary for fungi to adapt to their habitats. We demonstrated that the synergistic regulation of sensor histidine kinase (SLN1) and acetyl-CoA carboxylase (ACC1) plays a critical role in regulating the fungal response to Sinella curviseta stress. Furthermore, we found that the enhanced production of trehalose, carotenoids, and 5-MTHF plays crucial role in the resistance to the fungivore. Our results provide insights into the understanding of the adaptation of N. crassa to environmental stimuli.

Use of Trehalose as an Additive to Bacteriophage Vb_Pd_PDCC-1: Long-Term Preservation Analysis and Its Biocontrol Against Vibrio diabolicus Infection.

Phage therapy is a promising alternative to control bacterial diseases and the increasing problem of antibiotic resistance. In this sense, this research evaluates the viability of lyophilized vibrio phage vB_Pd_PDCC-1 using trehalose as a preservative excipient at different concentrations (4, 2, 1, and 0.5% w/v) and its potential for phage therapy application against a pathogenic bacteria Vibrio diabolicus in brine shrimp nauplii (Artemia franciscana). The lyophilized phages were stored at 4 and 23°C and rehydrated using biological sterile saline solution to test their viability at days 1, 15, and 60 post-lyophilization. The results showed that trehalose is beneficial in maintaining the viability of post-lyophilization phages (without titer losses) at 4°C and even at room temperature (23°C). When lyophilized phages with 4% w/v trehalose concentration were stored at 23°C, they had not titer losses among the trials; viability and titer concentration were maintained up to 60days at log 7. The use of lyophilized phage PDCC-1 increased brine shrimp survival and reduced Vibrio concentrations. The present study has identified trehalose as a promising lyophilization excipient to effectively preserve lyophilized bacteriophages for biotechnological applications and long-term storage.

Antifungal mechanism of Angelica sinensis essential oil against Penicillium roqueforti and its application in extending the shelf life of bread

There are a variety of reports on the application of Angelica sinensis essential oil (ASEO) in the biomedical field. However, the antifungal mechanism of ASEO has not been reported. In this study, the antifungal mechanism of ASEO against Penicillium roqueforti was investigated by proteomics and genomics. ASEO can increase the permeability of P. roqueforti cell membrane and decrease the content of lipid and trehalose. With the increase of glycerol content, the HOG signaling pathway can be upregulated. Consistent with the above phenotypic changes, proteomics confirmed that ASEO treatment inhibited the steroid synthesis pathway of P. roqueforti. The significant down-regulation of ERG4, ERG6, ERG25, SMT1, and FDFT1 gene expression confirmed this conclusion. Cluster+activates the MAPK and UPP signaling pathways and ultimately leads to cell apoptosis. The bread shelf life experiment showed that ASEO could extend the shelf life of bread up to day 7. This study provides new evidence for the antifungal activity of ASEO against P. roqueforti and will promote the use of ASEO in the preservation of food and agricultural products.

Analysis of the trehalose synthesis pathway of Physarum polycehalum

Desiccation is a severe survival problem for organisms. We have been studying the desiccation tolerance mechanisms in the true slime mold Physarum polycephalum. We measured the trehalose content of P. polycephalum vegetative cells (plasmodia) and drought cells (sclerotia). Surprisingly, we found that the content in sclerotia was about 473-fold greater than in the plasmodia. We then examined trehalose metabolism-related genes via RNAseq, and consequently found that trehalose 6-phosphate phosphorylase (T6pp) expression levels increased following desiccation. Next, we cloned and expressed the genes for T6pp, trehalose 6-phosphate synthase/phosphatase (Tps/Tpp), maltooligosyltrehalose trehalohydrolase (TreZ), and maltooligosyltrehalose synthase (TreY) in E. coli. Incidentally, TreY and TreZ clones have been reported in several prokaryotes, but not in eukaryotes. This report in P. polycephalum is the first evidence of their presence in a eukaryote species. Recombinant T6pp, TreY, and TreZ were purified and confirmed to be active. Our results showed that these enzymes catalyze reactions related to trehalose production, and their reaction kinetics follow the Michaelis-Menten equation.The t6pp mRNA levels of the sclerotia were about 15-fold higher than in the plasmodia. In contrast, the expression levels of TreZ and TreY showed no significant change between the sclerotia and plasmodia. Thus, T6pp is probably related to desiccation tolerance, whereas the contribution of TreY and TreZ is insufficient to account for the considerable accumulation of trehalose in sclerotia.

Effects of rapid cold-hardening and cold acclimation on egg survival and cryoprotectant contents in Ceracris kiangsu (Orthoptera: Arcypteridae)

Abstract The bamboo grasshopper, Ceracris kiangsu Tsai, is a serious pest of bamboo in China and Southeast Asia, and it overwinters as eggs for a period of up to 9 mo. Despite its importance, cold tolerance has not been thoroughly examined in this species. Thus, the present study investigated the low-temperature tolerance of overwintering eggs collected in the field, particularly the effects of rapid cold-hardening (RCH) and cold acclimation (ACC) on egg survival, and changes in the cryoprotectant contents. The supercooling point of overwintering eggs collected from the field was −23.9 °C, and their survival rate after exposure to −22 °C for 6 h was 26.6%, thereby suggesting that the cold tolerance strategy employed by C. kiangsu is freeze avoidance. After exposure to 0 and 4 °C for 12 and 24 h, or 0, 4, and 8 °C for 5 days, the survival rate of eggs subjected to −22 °C increased to approximately 50%, with significant effects of RCH and ACC. The glycerol levels in RCH and ACC treated eggs were also significantly higher than those in the control group, but the protein and trehalose contents were either reduced or not significantly altered. These results indicate that glycerol functions as a low molecular weight cryoprotectant in C. kiangsu eggs, and that RCH and ACC treatment facilitate its accumulation, thereby enhancing cold tolerance. Furthermore, the correlation between RCH and ACC was investigated.

Flight and flight energy accumulation related to the daily rhythm of juvenile hormone titer in the wing‐dimorphic cricket Velarifictorus aspersus

AbstractThe cricket Velarifictorus aspersus (Walker) (Orthoptera: Gryllidae) exhibits a wing dimorphism mediating two distinct life‐history strategies during early adulthood; long‐winged (LW) females mainly invest resources in flight, whereas short‐winged (SW) females invest more heavily in reproduction than LW females. To understand the relationships among juvenile hormone (JH), flight capacity, and energy accumulation, the daily rhythm of JH titer and flight activity, the concentrations of flight energy substances, and the influence of exogenous JH on flight activity and flight energy substances were investigated in V. aspersus. The results showed that the hemolymph JH titer exhibited a high‐amplitude daily rhythm in 5‐day‐old LW V. aspersus females, and the JH titer rose about 10× at 18:00 hours (6 h before lights off) and dropped to baseline levels after lights off. The females flew inactively (i.e., they floated in the air) from 14:00 to 19:00 hours during the light period, whereas they had a stronger flight capacity in the initial photophase and before lights out. The flight ability of LW females with 20 μg μL−1 JH treatments was significantly improved during periods of flight inactivity. After the peak JH titer, the concentrations of glycogen and trehalose in the flight muscles increased significantly. The LW females treated with JH during the inactive flight period had a significant increase in glycogen after 1 h and trehalose after 3 h. These results suggested that the high‐amplitude daily rhythm of the JH titer was correlated with accumulation of flight energy substance and flight capacity; that is, an elevated JH titer promoted the biosynthesis of flight energy substances, resulting in improvement of flight capacity.