The osmoregulated metabolism of trehalose contributes to production of type 1 fimbriae and bladder colonization by extraintestinal Escherichia coli strain BEN2908.

In Escherichia coli, the disaccharide trehalose can be metabolized as a carbon source or be accumulated as an osmoprotectant under osmotic stress. In hypertonic environments, E. coli accumulates trehalose in the cell by synthesis from glucose mediated by the cytosolic enzymes OtsA and OtsB. Trehalose in the periplasm can be hydrolyzed into glucose by the periplasmic trehalase TreA. We have previously shown that a treA mutant of extraintestinal E. coli strain BEN2908 displayed increased resistance to osmotic stress by 0.6 M urea, and reduced production of type 1 fimbriae, reduced invasion of avian fibroblasts, and decreased bladder colonization in a murine model of urinary tract infection. Since loss of TreA likely results in higher periplasmic trehalose concentrations, we wondered if deletion of otsA and otsB genes, which would lead to decreased internal trehalose concentrations, would reduce resistance to stress by 0.6 M urea and promote type 1 fimbriae production. The BEN2908ΔotsBA mutant was sensitive to osmotic stress by urea, but displayed an even more pronounced reduction in production of type 1 fimbriae, with the consequent reduction in adhesion/invasion of avian fibroblasts and reduced bladder colonization in the murine urinary tract. The BEN2908ΔtreAotsBA mutant also showed a reduction in production of type 1 fimbriae, but in contrast to the ΔotsBA mutant, resisted better than the wild type in the presence of urea. We hypothesize that, in BEN2908, resistance to stress by urea would depend on the levels of periplasmic trehalose, but type 1 fimbriae production would be influenced by the levels of cytosolic trehalose.

Trehalase inhibition in Helicoverpa armigera activates machinery for alternate energy acquisition.

Trehalose serves as a primary circulatory sugar in insects which is crucial in energy metabolism and stress recovery. It is hydrolyzed into two glucose molecules by trehalase. Silencing or inhibiting trehalase results in reduced fitness, developmental defects, and insect mortality. Despite its importance, the molecular response of insects to trehalase inhibition is not known. Here, we performed transcriptomic analyses of Helicoverpa armigera treated with validamycin A (VA), a trehalase inhibitor. VA ingestion resulted in increased mortality, developmental delay, and reduced ex vivo trehalase activity. Pathway enrichment and gene ontology analyses suggest that key genes involved in carbohydrate, protein, fatty acid, and mitochondria-related metabolisms are deregulated. The activation of protein and fat degradation may be necessary to fulfil energy requirements, evidenced by the dysregulated expression of critical genes in these metabolisms. Co-expression analysis supports the notion that trehalase inhibition leads to putative interaction with key regulators of other pathways. Metabolomics correlates with transcriptomics to show reduced levels of key energy metabolites. VA generates an energy-deficient condition, and insects activate alternate pathways to facilitate the energy demand. Overall, this study provides insights into the molecular mechanisms underlying the response of insects to trehalase inhibition and highlights potential targets for insect control.

Membrane-bound trehalase enhances cadmium tolerance by regulating cell apoptosis in Neocaridina denticulata sinensis.

Trehalase gene is mainly expressed in the digestive circulatory system for regulating energy metabolism and chitin synthesis in insects, but it is significantly expressed in gill for immunomodulation in shrimp. However, its function in regulating immunity, particularly metal resistance in crustaceans has yet to be elucidated. In this study, one Tre2 gene (NdTre2) was isolated from Neocaridina denticulata sinensis. It could bind to Cd2+ and inhibit its toxicity. Spatiotemporal expression analysis showed that the expression of NdTre2 was highest in the gill and significantly reduced at 12 h after Cd2+ stimulation. The transcriptomic analysis of the gill after NdTre2 knockdown showed that the expression of genes synthetizing 20E was up-regulated and the increased 20E could further induce apoptosis by activating the intrinsic mitochondrial pathway, exogenous death receptor-ligand pathway, and MAPK pathway. In vitro, overexpressing NdTre2 enhanced the tolerance of E. coli in Cd2+ environment. In summary, these results indicate that NdTre2 plays an essential role in regulating immunity and chitin metabolism in N. denticulata sinensis.

Validamycin A Inhibited FB1 Biosynthesis by the Target FvNth in Fusarium verticillioides.

Validamycin A (VMA) is an antifungal antibiotic derived from Streptomyces hygroscopicus commonly used in plant disease management. Surprisingly, VMA was discovered to impede the production of fumonisin B1 (FB1) in agricultural settings. However, the specific target of VMA in Fusarium verticillioides remained unclear. To unravel the molecular mechanism of VMA, ultrastructural observations unveiled damage to mitochondrial membranes. Trehalase (FvNth) was pinpointed as the target of VMA by utilizing a 3D-printed surface plasmon resonance sensor. Molecular docking identified Trp285, Arg447, Asp452, and Phe665 as the binding sites between VMA and FvNth. A ΔFvnth mutant lacking amino acids 250-670 was engineered through homologous recombination. Transcriptome analysis indicated that samples treated with VMA and ΔFvnth displayed similar expression patterns, particularly in the suppression of the FUM gene cluster. VMA treatment resulted in reduced trehalase and ATPase activity as well as diminished production of glucose, pyruvic acid, and acetyl-CoA. Conversely, these effects were absent in samples treated with ΔFvnth. This research proposes that VMA hinders acetyl-CoA synthesis by trehalase, thereby suppressing the FB1 biosynthesis. These findings present a novel target for the development of mycotoxin control agents.

Exploration of novel trehalases from cold-adapted Variovorax sp. PAMC28711: Functional characterization.

The cold-adapted bacterium Variovorax sp. PAMC28711 possesses two distinct glycoside hydrolase (GH) families of trehalase, GH15 and GH37. While numerous studies have explored bacterial trehalase, the presence of two different trehalase genes within a single strain has not been reported until now. Interestingly, despite both GH37 and GH15 trehalases serving the same purpose of degrading trehalose, but do not share the sequence similarity. The substrate specificity assay confirmed that Vtre37 and Vtre15 displayed hydrolytic activity on α, α-trehalose. The key catalytic sites were identified as D280 and E469 in Vtre37 and E389 and E554 in Vtre15 through site-directed mutation and confirmed these two enzymes belong to trehalase. In addition, Vtre37 exhibited a relatively high level of enzyme activity of 1306.33 (±53.091) µmolmg-1, whereas Vtre15 showed enzyme activity of 408.39 (±12.503) µmolmg-1. Moreover, Vtre37 performed admirably showing resistance to ethanol (10 %), with high stable at acidic pH range. Furthermore, both prediction and experimental results indicate that validoxylamine A showed a potent inhibitory activity against Vtre37 trehalase with a Ki value of 16.85 nM. Therefore, we postulate that Vtre37 could be utilized as an ethanol enhancer and designed for screening inhibitors related to the trehalose degradation pathway. Additionally, we believe that characterizing these bacterial trehalase contributes to a better understanding of trehalose metabolism and its biological importance in bacteria.

Impact of Three Thiazolidinone Compounds with Piperine Skeletons on Trehalase Activity and Development of Spodoptera frugiperda Larvae.

Trehalases (TREs) are pivotal enzymes involved in insect development and reproduction, making them prime targets for pest control. We investigated the inhibitory effect of three thiazolidinones with piperine skeletons (6a, 7b, and 7e) on TRE activity and assessed their impact on the growth and development of the fall armyworm (FAW), Spodoptera frugiperda. The compounds were injected into FAW larvae, while the control group was treated with 2% DMSO solvent. All three compounds effectively inhibited TRE activity, resulting in a significant extension of the pupal development stage. Moreover, the treated larvae exhibited significantly decreased survival rates and a higher incidence of abnormal phenotypes related to growth and development compared to the control group. These results suggest that these TRE inhibitors affect the molting of larvae by regulating the chitin metabolism pathway, ultimately reducing their survival rates. Consequently, these compounds hold potential as environmentally friendly insecticides.

Toxicological, biochemical, and in silico investigations of three trehalase inhibitors for new ways to control aphids.

Insect trehalases have been identified as promising new targets for pest control. These key enzymes are involved in trehalose hydrolysis and plays an important role in insect growth and development. In this contribution, plant and microbial compounds, namely validamycin A, amygdalin, and phloridzin, were evaluated for their effect, through trehalase inhibition, on Acyrthosiphon pisum aphid. The latter is part of the Aphididae family, main pests as phytovirus vectors and being very harmful for crops. Validamycin A was confirmed as an excellent trehalase inhibitor with an half maximal inhibitory concentration and inhibitor constant of 2.2 × 10-7 and 5 × 10-8 M, respectively, with a mortality rate of ~80% on a A. pisum population. Unlike validamycin A, the insect lethal efficacy of amygdalin and phloridzin did not correspond to their trehalase inhibition, probably due to their hydrolysis by insect ß-glucosidases. Our docking studies showed that none of the three compounds can bind to the trehalase active site, unlike their hydrolyzed counterparts, that is, validoxylamine A, phloretin, and prunasin. Validoxylamine A would be by far the best trehalase binder, followed by phloretin and prunasin.

Efficient production and characterization of a newly identified trehalase for inhibiting the formation of bacterial biofilms.

Trehalase has attracted widespread attention in medicine, agriculture, food, and ethanol industry due to its ability to specifically degrade trehalose. Efficient expression of trehalase remains a challenge. In this study, a putative trehalase-encoding gene (Tre-zm) from Zunongwangia mangrovi was explored using gene-mining strategy and heterologously expressed in E. coli. Trehalase activity reached 3374 U·mL-1 after fermentation optimization. The scale-up fermentation in a 15 L fermenter was achieved with a trehalase production of 15,068 U·mL-1. The recombinant trehalase TreZM was purified and characterized. It displayed optimal activity at 35 °C and pH 8.5, with Mn2+, Sn2+, Na+, and Fe2+ promoting the activity. Notably, TreZM showed significant inhibition effect on biofilm forming of Staphylococcus epidermidis. The combination of TreZM with a low concentration of antibiotics could inhibit 70 % biofilm formation of Staphylococcus epidermidis and 28 % of Pseudomonas aeruginosa. Hence, this study provides a promising candidate for industrial production of trehalase and highlights its potential application to control harmful biofilms.

Identification and RNAi-based function analysis of trehalase family genes in Frankliniella occidentalis (Pergande).

BACKGROUND: Insects utilize trehalases (TREs) to regulate energy metabolism and chitin biosynthesis, which are essential for their growth, development, and reproduction. TREs can therefore be used as potential targets for future insecticide development. However, the roles of TREs in Frankliniella occidentalis (Pergande), a serious widespread agricultural pest, remain unclear. RESULTS: Three TRE genes were identified in F. occidentalis and cloned, and their functions were then investigated via feeding RNA interference (RNAi) and virus-induced gene silencing (VIGS) assays. The results showed that silencing FoTRE1-1 or FoTRE1-2 significantly decreased expression levels of FoGFAT, FoPGM, FoUAP, and FoCHS, which are members of the chitin biosynthesis pathway. Silencing FoTRE1-1 or FoTRE2 significantly down-regulated FoPFK and FoPK, which are members of the energy metabolism pathway. These changes resulted in 2-fold decreases in glucose and glycogen content, 2-fold increases in trehalose content, and 1.5- to 2.0-fold decreases in chitinase activity. Furthermore, knocking down FoTRE1-1 or FoTRE1-2 resulted in deformed nymphs and pupae as a result of hindered molting. The VIGS assay for the three FoTREs revealed that FoTRE1-1 or FoTRE2 caused shortened ovarioles, and reduced egg-laying and hatching rates. CONCLUSION: The results suggest that FoTRE1-1 and FoTRE1-2 play important roles in the growth and development of F. occidentalis, while FoTRE1-1 and FoTRE2 are essential for its reproduction. These three genes could be candidate targets for RNAi-based management and control of this destructive agricultural pest. © 2024 Society of Chemical Industry.

Elucidation of bacterial trehalose-degrading trehalase and trehalose phosphorylase: physiological significance and its potential applications.

Bacteria possess diverse metabolic and genetic processes, resulting in the inability of certain bacteria to degrade trehalose. However, some bacteria do have the capability to degrade trehalose, utilizing it as a carbon source, and for defense against environmental stress. Trehalose, a disaccharide, serves as a carbon source for many bacteria, including some that are vital for pathogens. The degradation of trehalose is carried out by enzymes like trehalase (EC 3.2.1.28) and trehalose phosphorylase (EC 2.4.1.64/2.4.1.231), which are classified under the glycoside hydrolase families GH37, GH15, and GH65. Numerous studies and reports have explored the physiological functions, recombinant expression, enzymatic characteristics, and potential applications of these enzymes. However, further research is still being conducted to understand their roles in bacteria. This review aims to provide a comprehensive summary of the current understanding of trehalose degradation pathways in various bacteria, focusing on three key areas: (i) identifying different trehalose-degrading enzymes in Gram-positive and Gram-negative bacteria, (ii) elucidating the mechanisms employed by trehalose-degrading enzymes belonging to the glycoside hydrolases GH37, GH15, and GH65, and (iii) discussing the potential applications of these enzymes in different sectors. Notably, this review emphasizes the bacterial trehalose-degrading enzymes, specifically trehalases (GH37, GH15, and GH65) and trehalose phosphorylases (GH65), in both Gram-positive and Gram-negative bacteria, an aspect that has not been highlighted before.

The impact of UV-C radiation on the sugar metabolism of the red flour beetle Tribolium castaneum herbst (coleoptera; tenebrionidae).

PURPOSE: Ultraviolet-C (UV-C) is known to induce morphological abnormality in various parts of the red flour beetle, Tribolium castaneum, including its wings, antennae, eyes, legs, and reproductive organs. However, little is known about the effects of UV-C on T. castaneum's sugar content and enzyme activity. MATERIAL AND METHODS: We investigated the concentrations of glucose and trehalose as well as changes in trehalase activity in different developmental stages following UV-C radiation at different exposure periods (1, 2, 4, 8, 16, 32, and 64 min). In addition, the larval mortality and body weight were examined. RESULTS: A reduction in glucose content was recorded in 10-, 15- and 20-day-old larvae and trehalase enzyme activity was recorded in 5- and 10-day-old larvae, whereas an increase in trehalose content was found in adults irradiated with UV-C. In addition, UV-C radiation for 1-64 min caused larval mortality on the first and subsequent days post-irradiation. Moreover, UV-C irradiated larvae exhibited lower body weight, which aligned with the reduction of trehalase activity and glucose content from days 1-6 post-exposure, and the degree of these reductions corresponded to the exposure times. CONCLUSION: UV-C affected sugar content through the reduction of trehalase activity, and glucose declination may cause mortality in T. castaneum; however, further research is needed to provide a better understanding of the impact of UV-C on sugar metabolism.

Functional characterization of Nosema bombycis (microsporidia) trehalase 3.

Nosema bombycis, an obligate intracellular parasite, is a single-celled eukaryote known to infect various tissues of silkworms, leading to the manifestation of pebrine. Trehalase, a glycosidase responsible for catalyzing the hydrolysis of trehalose into two glucose molecules, assumes a crucial role in thermal stress tolerance, dehydration, desiccation stress, and asexual development. Despite its recognized importance in these processes, the specific role of trehalase in N. bombycis remains uncertain. This investigation focused on exploring the functions of trehalase 3 in N. bombycis (NbTre3). Immunofluorescence analysis of mature (dormant) spores indicated that NbTre3 primarily localizes to the spore membrane or spore wall, suggesting a potential involvement in spore germination. Reverse transcription-quantitative polymerase chain reaction results indicated that the transcriptional level of NbTre3 peaked at 6 h post N. bombycis infection, potentially contributing to energy storage for proliferation. Throughout the life cycle of N. bombycis within the host cell, NbTre3 was detected in sporoplasm during the proliferative stage rather than the sporulation stage. RNA interference experiments revealed a substantial decrease in the relative transcriptional level of NbTre3, accompanied by a certain reduction in the relative transcriptional level of Nb16S rRNA. These outcomes suggest that NbTre3 may play a role in the proliferation of N. bombycis. The application of the His pull-down technique identified 28 proteins interacting with NbTre3, predominantly originating from the host silkworm. This finding implies that NbTre3 may participate in the metabolism of the host cell, potentially utilizing the host cell's energy resources.

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.

Host trehalose metabolism disruption by validamycin A results in reduced fitness of parasitoid offspring.

The general cutworm, Spodoptera litura (Lepidoptera: Noctuidae) is a worldwide destructive omnivorous pest and the endoparasitoid wasp Meteorus pulchricornis (Hymenoptera: Braconidae) is the dominant endoparasitoid of S. litura larvae. Trehalase is a key enzyme in insect trehalose metabolism and plays an important role in the growth and development of insects. However, the specific function of trehalase in parasitoid and host associations has been less reported. In this study, we obtained two trehalase genes (SlTre1 and SlTre2) from our previously constructed S. litura transcriptome database; they were highly expressed in 3rd instar larvae. SlTre1 was mainly expressed in the midgut, and SlTre2 was expressed highest in the head. SlTre1 and SlTre2 were highly expressed 5 days after parasitization by M. pulchricornis. Treatment with the trehalase inhibitor validamycin A significantly inhibited the expression levels of SlTre1 and SlTre2, and the trehalase activity. Besides, the content of trehalose was increased but the content of glucose was decreased 24 h after validamycin A treatment in parasitized S. litura larvae. In addition, the immune-related genes in phenoloxidase (PO) pathway and fatty acid synthesis-related genes in lipid metabolism were upregulated in parasitized host larvae after validamycin A treatment. Importantly, the emergence rate, proportion of normal adults, and body size of parasitoid offspring was decreased in parasitized S. litura larvae after validamycin A treatment, indicating that validamycin A disrupts the trehalose metabolism of parasitized host and thus reduces the fitness of parasitoid offspring. The present study provides a novel perspective for coordinating the application of biocontrol and antibiotics in agroecosystem.

Biosensor for PCR amplicons by combining split trehalase and DNA-binding proteins: A proof of concept study.

The use of polymerase chain reaction (PCR) technology in low-cost settings has gained significant attention due to its ability to amplify and detect specific bacterial pathogen genes, aiding in the diagnosis of infectious diseases. PCR amplicons can be visualized by conventional endpoint agarose gel electrophoresis and fluorochrome-enabled real-time PCR. However, this is not practical in on-field tests due to cumbersome instrumentation, labor-intensive reaction preparation, and long time-to-results. Many studies have combined microfluidic devices or electrochemical dyes with PCR technology to enhance in-field operability. However, the high cost of manufacturing high-precision microfluidic chips and the dependence on non-portable readout equipment limit their further development. In this paper, we present a proof-of-principle study of a novel method combining split enzyme technology and DNA-binding proteins for the convenient and efficient detection of amplified genetic material from bacterial pathogens. The amplicon binding split trehalase assay (ABSTA) relies on incorporating specific recognition sequences of DNA-binding protein SpoIIID in tandem within one of the PCR primers. Applied by a Gram-type specific PCR assay, ABSTA was capable of discriminating Staphylococcus devriesei and Escherichia coli in <90 min after colony PCR amplicons bound split trehalase fragments-fused SpoIIID and triggered split enzyme complementation. The salt concentration, protein reagents versus DNA substrate ratio, direction and linker length of tandem recognition sites required for the complementation were optimized. The glucose produced by restored enzymatic activity was detectable by glucometer. With limited requirements for reaction preparation and the compatibility of ABSTA with commercially available handheld glucometers, this test platform has substantial potential to be implemented into a future point-of-care (POC) diagnostic tool for detecting pathogen specific genes with further improvement.

Mitigation of galvanized steel biocorrosion by Pseudomonas aeruginosa biofilm using a biocide enhanced by trehalase.

Pseudomonas aeruginosa is a facultative bacterium that is pathogenic. It is ubiquitous in the environment including air handling systems. It causes microbiologically influenced corrosion (MIC) aerobically and anaerobically. In this work, P. aeruginosa was grown as a nitrate reducing bacterium (NRB) in Luria-Bertani medium with KNO3 at 37 °C. Trehalase, an enzyme which plays a crucial role in biofilm formation was found to enhance the treatment of P. aeruginosa biofilm and its MIC against galvanized steel by tetrakis-hydroxymethyl phosphonium sulfate (THPS) green biocide. After a 7-d incubation, 30 ppm (w/w) trehalase reduced sessile cell count by 0.8-log, and it also reduced galvanized steel weight loss by 14%, compared to 2.3-log and 39%, respectively for the 30 ppm THPS treatment. The combination of 30 ppm THPS + 30 ppm trehalase reduced sessile cell count further by 0.1-log and weight loss by 13% compared to using THPS alone. Electrochemical corrosion measurements supported weight loss results. The injection of 20 ppm riboflavin into a 3-d P. aeruginosa broth failed to accelerate the corrosion rate, suggesting that nitrate reducing P. aeruginosa MIC of galvanized steel did not belong to extracellular electron transfer-MIC, because Zn was hydrolyzed after the microbe damaged the passive film.

[Prevalence of trehalase enzymopathy genetic determinants in Siberian and Russian Far East populations].

To date, it has been established that the patient's genotype plays a significant role in the formation of trehalase enzymopathy: the level of enzyme activity decreases when the G→A allele replacement occurs in the rs2276064 locus of the TREH gene. To assess the prevalence of trehalase deficiency, extensive population-based studies are needed. Clinical observations show that the reduced activity of bowel trehalase is more common in the Arctic than in European populations. The aim of this research was to analyze the frequency of the alleles and variants of trehalase gene (rs2276064 TREH) in the indigenous small-numbered populations of Siberia and the Russian Far East. Material and methods. Using the Infinium iSelect HD Custom BeadChip biochip on the iScan platform and real-time polymerase chain reaction on a Bio-Rad CFX96 Touch amplifier, genotyping of 1068 DNA samples was carried out, of which 711 represent 10 ethnic groups of the indigenous people of the North of Siberia and the Far East of the Russian Federation. Two reference groups of Russians (n=311) and Yakuts (n=46) represented the "Caucasoid" and "Mongoloid" poles of the Russian population. Results. The reduced trehalase activity that the heterozygous GA*TREH genotype determines can manifest itself in 19.8-53.7% of indigenous northerners. An additional 1.0 to 19.7% of the population are carriers of the AA*TREH genotype, which is associated with apparent trehalose malabsorption. The carriers may experience nausea, abdominal pain, and other dyspeptic symptoms after eating trehalose containing foods. The total risk of trehalase enzymopathy among the indigenous northerners in the Asian part of the Russian Federation is very high and can reach 60-70%. There is a gradient in the A*TREH allele frequencies in the small-numbered indigenous northern groups of Russia from the west (Khanty, Mansi, Nenets) to the east (peoples of the Far East). Conclusion. The results are consistent with previously reported data on the higher carriage of the A*TREH mutant allele in Mongoloid populations compared to Caucasoid groups. It was hypothesized that, while the initial A*TREH allele prevalence in Mongoloid groups was moderately high, an adaptation to a low-sugar protein-lipid "high-latitude" diet led to a weaker control over the maintenance of the carriage of the ancestral G allele. Trehalose malabsorption requires special attention of specialists in the field of nutrition, gastroenterology, public health, and medical genetics working in high-latitude regions.

Steroid hormone-dependent changes in trehalose physiology in the silkworm, Bombyx mori.

Holometabolous insects undergo metamorphosis to reconstruct their body to the adult form during pupal period. Since pupae cannot take any diets from the outside because of a hard pupal cuticle, those insects stock up on nutrients sufficient for successful metamorphosis during larval feeding period. Among those nutrients, carbohydrates are stored as glycogen or trehalose, which is the major blood sugar in insects. The hemolymph trehalose is constantly high during the feeding period but suddenly decreases at the beginning of the prepupal period. It is believed that trehalase, which is a trehalose-hydrolyzing enzyme, becomes highly active to reduce hemolymph trehalose level during prepupal period. This change in the hemolymph trehalose level has been interpreted as the physiological shift from storage to utilization of trehalose at that stage. Although this shift in trehalose physiology is indispensable for energy production required for successful metamorphosis, little is known on the regulatory mechanisms of trehalose metabolism in accordance with developmental progress. Here, we show that ecdysone, an insect steroid hormone, plays essential roles in the regulation of soluble trehalase activity and its distribution in the midgut of silkworm, Bombyx mori. In the end of larval period, soluble trehalase was highly activated in the midgut lumen. This activation was disappeared in the absence of ecdysone and also restored by ecdysone administration. Our present results suggest that ecdysone is essentially required for the changes in the function of the midgut on trehalose physiology as development progresses.

The antifungal effect induced by itraconazole in Candida parapsilosis largely depends on the oxidative stress generated at the mitochondria.

In Candida parapsilosis, homozygous disruption of the two genes encoding trehalase activity increased the susceptibility to Itraconazole compared with the isogenic parental strain. The fungicidal effect of this azole can largely be counteracted by preincubating growing cells with rotenone and the protonophore 2,4-Dinitrophenol. In turn, measurement of endogenous reactive oxygen species formation by flow cytometry confirmed that Itraconazole clearly induced an internal oxidative stress, which can be significantly abolished in rotenone-exposed cells. Analysis of the antioxidant enzymatic activities of catalase and superoxide dismutase pointed to a moderate decrease of catalase in trehalase-deficient mutant cells compared to the wild type, with an additional increase upon addition of rotenone. These enzymatic changes were imperceptible in the case of superoxide dismutase. Alternative assays with Voriconazole led to a similar profile in the results regarding cell growth and antioxidant activities. Collectively, our data suggest that the antifungal action of Itraconazole on C. parapsilosis is dependent on a functional mitochondrial activity. They also suggest that the central metabolic pathways in pathogenic fungi should be considered as preferential antifungal targets in new research.

Urinary trehalase activitiy in contrast-associated acute kidney injury.

OBJECTIVE: Contrast-associated acute kidney injury (CA-AKI) is the third most common cause of hospital-acquired AKI. Sensitive biomarkers can detect kidney injury early on because kidney damage begins immediately after the administration of a contrast medium. Due to its proximal tubule specificity, urinary trehalase can be a useful and early marker for detecting tubular damage. This study aimed to reveal the power of urinary trehalase activity in diagnosing CA-AKI. PATIENTS AND METHODS: This is a prospective, observational, and diagnostic validity study. The study was performed in an academic research hospital's emergency department. Patients aged 18 years and over who underwent contrast-enhanced computed tomography in the emergency department were included in the study. Urinary trehalase activities were measured before and 12, 24, and 48 hours after the administration of a contrast medium. The primary outcome was the occurrence of CA-AKI, while the secondary outcomes were risk factors for CA-AKI, duration of hospital stay after contrast use, and the mortality rate in the hospital. RESULTS: A statistically significant difference between the CA-AKI group and the non-AKI group was found in the activities measured 12 hours after the administration of the contrast medium. Notably, the mean age of the patient group with CA-AKI was considerably higher than that of the non-AKI group. The risk of mortality was found to be remarkably more elevated in patients with CA-AKI. Further, there was a positive correlation between trehalase activity and HbA1c. In addition, a crucial correlation was found between trehalase activity and poor glycemic control. CONCLUSIONS: Urinary trehalase activity can be useful as a marker of acute kidney injuries due to proximal tubule damage. In the diagnosis of CA-AKI, especially the activity of trehalase in the 12th hour might be useful.