Preservation of membranes in anhydrobiotic organisms: the role of trehalose

Fruit Fly in a Challenging Environment: Impact of Short-Term Temperature Stress on the Survival, Development, Reproduction, and Trehalose Metabolism of Bactrocera dorsalis (Diptera: Tephritidae)

An understanding of physiological damage and population development caused by uncomfortable temperature plays an important role in pest control. In order to clarify the adaptability of different temperatures and physiological response mechanism of B. dorsalis, we focused on the adaptation ability of this pest to environmental stress from physiological and ecological viewpoints. In this study, we explored the relationship between population parameters and glucose, glycogen, trehalose, and trehalose-6-phosphate synthase responses to high and low temperatures. Compared with the control group, temperature stress delayed the development duration of all stages, and the survival rates and longevity decreased gradually as temperature decreased to 0 °C and increased to 36 °C. Furthermore, with low temperature decrease from 10 °C to 0 °C, the average fecundity per female increased at 10 °C but decreased later. Reproduction of the species was negatively affected during high-temperature stresses, reaching the lowest value at 36 °C. In addition to significantly affecting biological characteristics, temperature stress influenced physiological changes of B. dorsalis in cold and heat tolerance. When temperature deviated significantly from the norm, the levels of substances associated with temperature resistance were altered: glucose, trehalose, and TPS levels increased, but glycogen levels decreased. These results suggest that temperature stresses exert a detrimental effect on the populations' survival, but the metabolism of trehalose and glycogen may enhance the pest's temperature resistance.

The Different Metabolic Responses of Resistant and Susceptible Wheats to Fusarium graminearum Inoculation

Fusarium head blight (FHB) is a serious wheat disease caused by Fusarium graminearum (Fg) Schwabe. FHB can cause huge loss in wheat yield. In addition, trichothecene mycotoxins produced by Fg are harmful to the environment and humans. In our previous study, we obtained two mutants TPS1⁻ and TPS2⁻. Neither of these mutants could synthesize trehalose, and they produced fewer mycotoxins. To understand the complex interaction between Fg and wheat, we systematically analyzed the metabolic responses of FHB-susceptible and -resistant wheat to ddH₂O, the TPS⁻ mutants and wild type (WT) using NMR combined with multivariate analysis. More than 40 metabolites were identified in wheat extracts including sugars, amino acids, organic acids, choline metabolites and other metabolites. When infected by Fg, FHB-resistant and -susceptible wheat plants showed different metabolic responses. For FHB-resistant wheat, there were clear metabolic differences between inoculation with mutants (TPS1⁻/TPS2⁻) and with ddH₂O/WT. For the susceptible wheat, there were obvious metabolic differences between inoculation with mutant (TPS1⁻/TPS2⁻) and inoculation with ddH₂O; however, there were no significant metabolic differences between inoculation with TPS⁻ mutants and with WT. Specifically, compared with ddH₂O, resistant wheat increased the levels of Phe, p-hydroxy cinnamic acid (p-HCA), and chlorogenic acid in response to TPS⁻ mutants; however, susceptible wheat did not. Shikimate-mediated secondary metabolism was activated in the FHB-resistant wheat to inhibit the growth of Fg and reduce the production of mycotoxins. These results can be helpful for the development of FHB-resistant wheat varieties, although the molecular relationship between the trehalose biosynthetic pathway in Fg and shikimate-mediated secondary metabolism in wheat remains to be further studied.

Yeast osmoregulation - glycerol still in pole position

In response to osmotic dehydration cells sense, signal, alter gene expression, and metabolically counterbalance osmotic differences. The main compatible solute/osmolyte that accumulates in yeast cells is glycerol, which is produced from the glycolytic intermediate dihydroxyacetone phosphate. This review covers recent advancements in understanding mechanisms involved in sensing, signaling, cell-cycle delays, transcriptional responses as well as post-translational modifications on key proteins in osmoregulation. The protein kinase Hog1 is a key-player in many of these events, however, there is also a growing body of evidence for important Hog1-independent mechanisms playing vital roles. Several missing links in our understanding of osmoregulation will be discussed and future avenues for research proposed. The review highlights that this rather simple experimental system—salt/sorbitol and yeast—has developed into an enormously potent model system unravelling important fundamental aspects in biology.

Synthesis and Application of Trehalose Materials

Trehalose is a naturally occurring, nonreducing disaccharide that is widely used in the biopharmaceutical, food, and cosmetic industries due to its stabilizing and cryoprotective properties. Over the years, scientists have developed methodologies to synthesize linear polymers with trehalose units either in the polymer backbone or as pendant groups. These macromolecules provide unique properties and characteristics, which often outperform trehalose itself. Additionally, numerous reports have focused on the synthesis and formulation of materials based on trehalose, such as nanoparticles, hydrogels, and thermoset networks. Among many applications, these polymers and materials have been used as protein stabilizers, as gene delivery systems, and to prevent amyloid aggregate formation. In this Perspective, recent developments in the synthesis and application of trehalose-based linear polymers, hydrogels, and nanomaterials are discussed, with a focus on utilization in the biomedical field.

Intracellular trehalose accumulation via the Agt1 transporter promotes freeze-thaw tolerance in Saccharomyces cerevisiae

AIM

This study is to investigate the use of a constitutively expressed trehalose transport protein to directly control intracellular trehalose levels and protect baker's yeast (Saccharomyces cerevisiae) cells against freeze-thaw stress in vivo.

METHODS AND RESULTS

We used a constitutively overexpressed Agt1 transporter system to investigate the role of trehalose in the freeze-thaw tolerance of yeast cells by regulating intracellular trehalose concentrations independently of intracellular biosynthesis. Using this method, we found that increasing intracellular trehalose in yeast cells improved cell survival rate after 8 days of freezing at -80°C and -20°C. We also observed that freeze-thaw tolerance promoted by intracellular trehalose only occurs in highly concentrated cell pellets rather than cells in liquid suspension.

CONCLUSIONS

Trehalose is sufficient to provide freeze-thaw tolerance using our Agt1 overexpression system. Freeze-thaw tolerance can be further enhanced by deletion of genes encoding intracellular trehalose degradation enzymes.

SIGNIFICANCE AND IMPACT OF STUDY

These findings are relevant to improving the freeze-thaw tolerance of baker's yeast in the frozen baked goods industry through engineering strains that can accumulate intracellular trehalose via a constitutively expressed trehalose transporter and inclusion of trehalose into the growth medium.

Deciphering the Biological Enigma-Genomic Evolution Underlying Anhydrobiosis in the Phylum Tardigrada and the Chironomid Polypedilum vanderplanki

Anhydrobiosis, an ametabolic dehydrated state triggered by water loss, is observed in several invertebrate lineages. Anhydrobiotes revive when rehydrated, and seem not to suffer the ultimately lethal cell damage that results from severe loss of water in other organisms. Here, we review the biochemical and genomic evidence that has revealed the protectant molecules, repair systems, and maintenance pathways associated with anhydrobiosis. We then introduce two lineages in which anhydrobiosis has evolved independently: Tardigrada, where anhydrobiosis characterizes many species within the phylum, and the genus Polypedilum, where anhydrobiosis occurs in only two species. Finally, we discuss the complexity of the evolution of anhydrobiosis within invertebrates based on current knowledge, and propose perspectives to enhance the understanding of anhydrobiosis.

Carbohydrates based stimulus responsive nanocarriers for cancer-targeted chemotherapy: A review of current practices

INTRODUCTION

Many nanocarriers have been developed to react physicochemically to exterior stimuli like ultrasonic, light, heat, and magnetic fields, along with various internal stimuli including pH, hypoxia, enzyme, and redox potential. Nanocarriers are capable to respond various stimuli within the cancer cells to enable on-demand drug delivery, activation of bioactive compounds, controlled drug release, and targeting ligands, as well as size, charge, and conformation conversion, enabling sensing and signaling, overcoming multidrug resistance, accurate diagnosis, and precision therapy.

AREAS COVERED

Carbohydrates are ubiquitous biomolecules with a high proclivity for supramolecular network formation. Numerous carbohydrate-based nanomaterials have been used in biological solicitations and stimuli-based responses. Particular emphasis has been placed on the utilization of carbohydrate-based NPs and nanogels in various fields including imaging, drug administration, and tissue engineering. Because the assembly process is irreversible, carbohydrate-based systems are excellent ingredients for the development of stimulus-responsive nanocarriers for cancer-targeted chemotherapy. This review aims to summarise current research on carbohydrate-based nanomaterials, with an emphasis on stimuli-sensitive nanocarriers for cancer-targeted chemotherapy.

EXPERT OPINION

Carbohydrates-based stimulus-responsive nanomaterials have been proved highly efficient for targeted delivery of anticancer drugs, thus leading to effective chemotherapy with minimum off-target effects.

Metabolomic Profile of the Fungus Cryomyces antarcticus Under Simulated Martian and Space Conditions as Support for Life-Detection Missions on Mars

The identification of traces of life beyond Earth (e.g., Mars, icy moons) is a challenging task because terrestrial chemical-based molecules may be destroyed by the harsh conditions experienced on extraterrestrial planetary surfaces. For this reason, studying the effects on biomolecules of extremophilic microorganisms through astrobiological ground-based space simulation experiments is significant to support the interpretation of the data that will be gained and collected during the ongoing and future space exploration missions. Here, the stability of the biomolecules of the cryptoendolithic black fungus Cryomyces antarcticus, grown on two Martian regolith analogues and on Antarctic sandstone, were analysed through a metabolomic approach, after its exposure to Science Verification Tests (SVTs) performed in the frame of the European Space Agency (ESA) Biology and Mars Experiment (BIOMEX) project. These tests are building a set of ground-based experiments performed before the space exposure aboard the International Space Station (ISS). The analysis aimed to investigate the effects of different mineral mixtures on fungal colonies and the stability of the biomolecules synthetised by the fungus under simulated Martian and space conditions. The identification of a specific group of molecules showing good stability after the treatments allow the creation of a molecular database that should support the analysis of future data sets that will be collected in the ongoing and next space exploration missions.

The Impact of Dry Yeast Rehydrated in Different Plasma Treated Waters (PTWs) on Fermentation Process and Quality of Beer

Yeast plays a key role in the production of alcoholic beverages. Effective fermentation requires appropriate conditions to ensure the production of high-quality beer. The paper discusses the effect of dry brewing yeast (Saccharomyces cerevisiae and Saccharomyces pastorianus) after rehydration with water exposed to low-temperature, low-pressure glow plasma (PTW) in the atmosphere of air (PTWAir) and nitrogen (PTWN) in the course of the fermentation process, the formation of volatile compounds and other quality parameters of the finished beer. The obtained results show that the lager yeast strain initiated the process of fermentation faster after rehydration in the presence of PTWAir compared to all of the other treatments. It was observed that PTWAir significantly changed the composition of volatile compounds in the finished beer, especially by increasing the number of terpenes, which are compounds that positively shape the aroma of beer. In the case of PTWN samples, lower alcohol content, real extract, apparent extract and amount of biomass were observed in all analyzed strains.

Squalene-Based Nano-Assemblies Improve the Pro-Autophagic Activity of Trehalose

The disaccharide trehalose is a well-established autophagy inducer, but its therapeutic application is severely hampered by its low potency and poor pharmacokinetic profile. Thus, we targeted the rational design and synthesis of trehalose-based small molecules and nano objects to overcome such issues. Among several rationally designed trehalose-centered putative autophagy inducers, we coupled trehalose via suitable spacers with known self-assembly inducer squalene to yield two nanolipid-trehalose conjugates. Squalene is known for its propensity, once linked to a bioactive compound, to assemble in aqueous media in controlled conditions, internalizing its payload and forming nanoassemblies with better pharmacokinetics. We assembled squalene conjugates to produce the corresponding nanoassemblies, characterized by a hydrodynamic diameter of 188 and 184 nm and a high stability in aqueous media as demonstrated by the measured Z-potential. Moreover, the nanoassemblies were characterized for their toxicity and capability to induce autophagy in vitro.

High Resistance to Quinclorac in Multiple-Resistant Echinochloa colona Associated with Elevated Stress Tolerance Gene Expression and Enriched Xenobiotic Detoxification Pathway

Echinochloa colona and other species in this genus are a threat to global rice production and food security. Quinclorac, an auxin mimic, is a common herbicide for grass weed control in rice, and Echinochloa spp. have evolved resistance to it. The complete mode of quinclorac action and subsequent evolution of resistance is not fully understood. We analyzed the de novo transcriptome of multiple-herbicide-resistant (ECO-R) and herbicide-susceptible genotypes in response to quinclorac. Several biological processes were constitutively upregulated in ECO-R, including carbon metabolism, photosynthesis, and ureide metabolism, indicating improved metabolic efficiency. The transcriptional change in ECO-R following quinclorac treatment indicates an efficient response, with upregulation of trehalose biosynthesis, which is also known for abiotic stress mitigation. Detoxification-related genes were induced in ECO-R, mainly the UDP-glycosyltransferase (UGT) family, most likely enhancing quinclorac metabolism. The transcriptome data also revealed that many antioxidant defense elements were uniquely elevated in ECO-R to protect against the auxin-mediated oxidative stress. We propose that upon quinclorac treatment, ECO-R detoxifies quinclorac utilizing UGT genes, which modify quinclorac using the sufficient supply of UDP-glucose from the elevated trehalose pathway. Thus, we present the first report of upregulation of trehalose synthesis and its association with the herbicide detoxification pathway as an adaptive mechanism to herbicide stress in Echinochloa, resulting in high resistance.

A versatile hydrogel network-repairing strategy achieved by the covalent-like hydrogen bond interaction

Hydrogen bond engineering is widely exploited to impart stretchability, toughness, and self-healing capability to hydrogels. However, the enhancement effect of conventional hydrogen bonds is severely limited by their weak interaction strength. In nature, some organisms tolerate extreme conditions due to the strong hydrogen bond interactions induced by trehalose. Here, we report a trehalose network-repairing strategy achieved by the covalent-like hydrogen bonding interactions to improve the hydrogels' mechanical properties while simultaneously enabling them to tolerate extreme environmental conditions and retain synthetic simplicity, which proves to be useful for various kinds of hydrogels. The mechanical properties of trehalose-modified hydrogels including strength, stretchability, and fracture toughness are substantially enhanced under a wide range of temperatures. After dehydration, the modified hydrogels maintain their hyperelasticity and functions, while the unmodified hydrogels collapse. This strategy provides a versatile methodology for synthesizing extremotolerant, highly stretchable, and tough hydrogels, which expand their potential applications to various conditions.

Red Blood Cell Cryopreservation with Minimal Post-Thaw Lysis Enabled by a Synergistic Combination of a Cryoprotecting Polyampholyte with DMSO/Trehalose

From trauma wards to chemotherapy, red blood cells are essential in modern medicine. Current methods to bank red blood cells typically use glycerol (40 wt %) as a cryoprotective agent. Although highly effective, the deglycerolization process, post-thaw, is time-consuming and results in some loss of red blood cells during the washing procedures. Here, we demonstrate that a polyampholyte, a macromolecular cryoprotectant, synergistically enhances ovine red blood cell cryopreservation in a mixed cryoprotectant system. Screening of DMSO and trehalose mixtures identified optimized conditions, where cytotoxicity was minimized but cryoprotective benefit maximized. Supplementation with polyampholyte allowed 97% post-thaw recovery (3% hemolysis), even under extremely challenging slow-freezing and -thawing conditions. Post-thaw washing of the cryoprotectants was tolerated by the cells, which is crucial for any application, and the optimized mixture could be applied directly to cells, causing no hemolysis after 1 h of exposure. The procedure was also scaled to use blood bags, showing utility on a scale relevant for application. Flow cytometry and adenosine triphosphate assays confirmed the integrity of the blood cells post-thaw. Microscopy confirmed intact red blood cells were recovered but with some shrinkage, suggesting that optimization of post-thaw washing could further improve this method. These results show that macromolecular cryoprotectants can provide synergistic benefit, alongside small molecule cryoprotectants, for the storage of essential cell types, as well as potential practical benefits in terms of processing/handling.

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 3308 bp, 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 3 h to 24 h 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.

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.

Transformation process of ice crystallized from a glassy dilute trehalose aqueous solution

Crystal growth of ice Isd occurring after crystallization of a glassy dilute trehalose aqueous solution is slower than that of ice Isd in a dilute glycerol solution and pure ice Isd, and ice Isd in trehalose aqueous solution survives to ∼230 K.

Water is a preservative of microbes

Water is the cellular milieu, drives all biochemistry within Earth's biosphere and facilitates microbe-mediated decay processes. Instead of reviewing these topics, the current article focuses on the activities of water as a preservative-its capacity to maintain the long-term integrity and viability of microbial cells-and identifies the mechanisms by which this occurs. Water provides for, and maintains, cellular structures; buffers against thermodynamic extremes, at various scales; can mitigate events that are traumatic to the cell membrane, such as desiccation-rehydration, freeze-thawing and thermal shock; prevents microbial dehydration that can otherwise exacerbate oxidative damage; mitigates against biocidal factors (in some circumstances reducing ultraviolet radiation and diluting solute stressors or toxic substances); and is effective at electrostatic screening so prevents damage to the cell by the intense electrostatic fields of some ions. In addition, the water retained in desiccated cells (historically referred to as 'bound' water) plays key roles in biomacromolecular structures and their interactions even for fully hydrated cells. Assuming that the components of the cell membrane are chemically stable or at least repairable, and the environment is fairly constant, water molecules can apparently maintain membrane geometries over very long periods provided these configurations represent thermodynamically stable states. The spores and vegetative cells of many microbes survive longer in the presence of vapour-phase water (at moderate-to-high relative humidities) than under more-arid conditions. There are several mechanisms by which large bodies of water, when cooled during subzero weather conditions remain in a liquid state thus preventing potentially dangerous (freeze-thaw) transitions for their microbiome. Microbial life can be preserved in pure water, freshwater systems, seawater, brines, ice/permafrost, sugar-rich aqueous milieux and vapour-phase water according to laboratory-based studies carried out over periods of years to decades and some natural environments that have yielded cells that are apparently thousands, or even (for hypersaline fluid inclusions of mineralized NaCl) hundreds of millions, of years old. The term preservative has often been restricted to those substances used to extend the shelf life of foods (e.g. sodium benzoate, nitrites and sulphites) or those used to conserve dead organisms, such as ethanol or formaldehyde. For living microorganisms however, the ultimate preservative may actually be water. Implications of this role are discussed with reference to the ecology of halophiles, human pathogens and other microbes; food science; biotechnology; biosignatures for life and other aspects of astrobiology; and the large-scale release/reactivation of preserved microbes caused by global climate change.

Lipids and Trehalose Actively Cooperate in Heat Stress Management of Schizosaccharomyces pombe

Homeostatic maintenance of the physicochemical properties of cellular membranes is essential for life. In yeast, trehalose accumulation and lipid remodeling enable rapid adaptation to perturbations, but their crosstalk was not investigated. Here we report about the first in-depth, mass spectrometry-based lipidomic analysis on heat-stressed Schizosaccharomyces pombe mutants which are unable to synthesize (tps1Δ) or degrade (ntp1Δ) trehalose. Our experiments provide data about the role of trehalose as a membrane protectant in heat stress. We show that under conditions of trehalose deficiency, heat stress induced a comprehensive, distinctively high-degree lipidome reshaping in which structural, signaling and storage lipids acted in concert. In the absence of trehalose, membrane lipid remodeling was more pronounced and increased with increasing stress dose. It could be characterized by decreasing unsaturation and increasing acyl chain length, and required de novo synthesis of stearic acid (18:0) and very long-chain fatty acids to serve membrane rigidification. In addition, we detected enhanced and sustained signaling lipid generation to ensure transient cell cycle arrest as well as more intense triglyceride synthesis to accommodate membrane lipid-derived oleic acid (18:1) and newly synthesized but unused fatty acids. We also demonstrate that these changes were able to partially substitute for the missing role of trehalose and conferred measurable stress tolerance to fission yeast cells.

Dipropinonates of Sugar Alcohols as Water-Soluble, Nontoxic CPAs for DMSO-Free Cell Cryopreservation

Sorbitol, mannitol, xylitol, and erythritol, four readily available sugar alcohols with poor or no membrane permeability, are converted into their corresponding dipropionates by acylating their primary hydroxyl groups. With enhanced membrane permeability, these diesters are expected to permeate the cell membranes and, upon their hydrolysis, release the corresponding sugar alcohols inside the cells. NIH-3T3 cells incubated with these diesters before being frozen at -80 °C exhibited considerably higher total recovery over those incubated with the free sugar alcohols or media only. Among the four diesters, those of sorbitol, especially mannitol, showed cryoprotective effects comparable to that shown by 5% DMSO. This work has demonstrated the feasibility of converting readily available, naturally occurring compounds into membrane-permeable derivatives that serve as water-soluble, nontoxic alternatives to DMSO.

Molecular Mechanism of Cell Membrane Protection by Sugars: A Study of Interfacial H-Bond Networks

Sugars function as bioprotectants by stabilizing biomolecules during dehydration, thermal stress, and freeze-thaw cycles. A buildup of sugars occurs in many organisms upon their exposure to extreme conditions. Understanding sugar's bioprotective effects on membranes is achieved by characterizing the H-bond networks at the lipid-water interface. Here, we report the headgroup H-bond populations, structures, and dynamics of 1,2-dimyristoyl-sn-glycero-3-phosphocholine vesicles in concentrated glucose solutions using ultrafast two-dimensional infrared spectroscopy in conjunction with molecular dynamics simulations. H-Bond populations and dynamics at the ester carbonyl positions are largely unaffected even at very high, 600 mg/mL, sugar concentrations. In addition, dynamics exhibit a slight nonmonotonic dependence on sugar concentration. Simulations, which are in near-quantitative agreement with measured dynamics, show that the H-bond structure remains largely intact by the existence of sugar. This study shows that the bioprotection of sugar is realized through stable lipid-saccharide-water H-bond networks at the membrane interface that mimic the H-bond networks in pure water.

Protein Hydration in a Bioprotecting Mixture

We combined broad-band depolarized light scattering and infrared spectroscopies to study the properties of hydration water in a lysozyme-trehalose aqueous solution, where trehalose is present above the concentration threshold (30% in weight) relevant for biopreservation. The joint use of the two different techniques, which were sensitive to inter-and intra-molecular degrees of freedom, shed new light on the molecular mechanism underlying the interaction between the three species in the mixture. Thanks to the comparison with the binary solution cases, we were able to show that, under the investigated conditions, the protein, through preferential hydration, remains strongly hydrated even in the ternary mixture. This supported the water entrapment scenario, for which a certain amount of water between protein and sugar protects the biomolecule from damage caused by external agents.

Autophagy Induced by Trehalose Alleviates Apoptosis of Human Aortic Endothelial Cells After Cryopreservation

Cryoprotectants are crucial factors in cell cryopreservation. Trehalose (Tre), a nontoxic, nonreducing, and natural disaccharide, has the potential to protect cells as a cryoprotectant. As an inducer of autophagy, Tre can influence the development of many diseases and may also have an effect on cell cryopreservation through this mechanism. In this study, human aortic endothelial cells were preserved in different cryopreservation fluids with or without dimethyl sulfoxide and Tre was added. Subsequently, the expression of the main autophagy-related genes LC3, BECN, and P62, cell death and apoptosis, and the proliferation rate were measured in different groups after cryopreservation. Our data showed that Tre can improve the expression of the autophagy-related genes LC3 and BECN and reduce the expression of P62. Dead/alive staining and flow cytometry showed that cell death and cell apoptosis were reduced during cryopreservation with Tre. In addition, the cell proliferation rate after thawing was increased in the Tre group when compared with others. These results all indicated that there might be a connection between Tre-triggered autophagy and the protective role of Tre in cell cryopreservation. Furthermore, strategies to regulate autophagy to reduce apoptosis in this process should be investigated in future research.

Advanced biomaterials in cell preservation: Hypothermic preservation and cryopreservation

Cell-based medicine has made great advances in clinical diagnosis and therapy for various refractory diseases, inducing a growing demand for cell preservation as support technology. However, the bottleneck problems in cell preservation include low efficiency and poor biocompatibility of traditional protectants. In this review, cell preservation technologies are categorized according to storage conditions: hypothermic preservation at 1 °C~35 °C to maintain short-term cell viability that is useful in cell diagnosis and transport, while cryopreservation at -196 °C~-80 °C to maintain long-term cell viability that provides opportunities for therapeutic cell product storage. Firstly, the background and developmental history of the protectants used in the two preservation technologies are briefly introduced. Secondly, the progress in different cellular protection mechanisms for advanced biomaterials are discussed in two preservation technologies. In hypothermic preservation, the hypothermia-induced and extracellular matrix-loss injuries to cells are comprehensively summarized, as well as the recent biomaterials dependent on regulation of cellular ATP level, stabilization of cellular membrane, balance of antioxidant defense system, and supply of mimetic ECM to prolong cell longevity are provided. In cryopreservation, cellular injuries and advanced biomaterials that can protect cells from osmotic or ice injury, and alleviate oxidative stress to allow cell survival are concluded. Last, an insight into the perspectives and challenges of this technology is provided. We envision advanced biocompatible materials for highly efficient cell preservation as critical in future developments and trends to support cell-based medicine. STATEMENT OF SIGNIFICANCE: Cell preservation technologies present a critical role in cell-based applications, and more efficient biocompatible protectants are highly required. This review categorizes cell preservation technologies into hypothermic preservation and cryopreservation according to their storage conditions, and comprehensively reviews the recently advanced biomaterials related. The background, development, and cellular protective mechanisms of these two preservation technologies are respectively introduced and summarized. Moreover, the differences, connections, individual demands of these two technologies are also provided and discussed.

Effect of devitrification on the survival and resistance of dried Saccharomyces cerevisiae yeast

Yeasts are anhydrobiotes that accumulate large amounts of trehalose, which is involved in the vitrification of the cytoplasm during drastic desiccation. The effect of devitrification, which can be induced by the transient exposure of desiccated yeasts to increased humidity or elevated temperature, on the survival of yeast has been studied. A glass transition temperature (T_g)/water activity (a_w) diagram of yeast was constructed based on differential scanning calorimetry analysis. The survival rate of yeasts that were equilibrated at different relative humidities (RHs) and temperature values over their T_g range was measured. The results revealed a long period of cell preservation at an intermediate RH (55%), with 100% survival observed after 3 months, a loss of 1.24 log colony-forming units/g recorded after 1 year at 25 °C and full preservation of viability at 75 °C for 60 min and at 100 °C and 12% RH for up to 10 min. These findings led us to conclude that dried yeast can resist low or intermediate RH values and elevated temperatures in the devitrified state. Considering the thermal and humidity fluctuations occurring in the yeast environments, we hypothesized that the supercooled state, which occurs immediately above the T_g after rehydration or heating, is a protective state that is involved in the persistence of yeasts at intermediate humidity levels. KEY POINTS: • Yeast survival for months in a supercooled state is observed at room temperature. • Dried yeasts survive a 10-min exposure to 100 °C in the supercooled state. • The supercooled state is suitable for yeast preservation.

Tardigrada: An Emerging Animal Model to Study the Endoplasmic Reticulum Stress Response to Environmental Extremes

Tardigrada (also known as "water bears") are hydrophilous microinvertebrates with a bilaterally symmetrical body and four pairs of legs usually terminating with claws. Water bears are quite complex animals and range from 50 to 1200 μm in length. Their body is divided into a head segment and four trunk segments, each bearing a pair of legs. They inhabit almost all terrestrial and aquatic environments, from the ocean depths to highest mountains ranges. However, one of their best known and unusual features is their capability for cryptobiosis. In this state tardigrades are able to survive extremely low and high temperatures and atmospheric pressures, complete lack of water, high doses of radiation, high concentrations of toxins and even a cosmic vacuum. The cellular mechanisms enabling cryptobiosis are poorly understood, although it appears the synthesis of certain types of molecules (sugars and proteins) enable the prevention of cellular damage at different levels. The endoplasmic reticulum (ER) is a morphologically and functionally diverse organelle able to integrate multiple extracellular and internal signals and generate adaptive cellular responses. However, the ER morphology and activity in the case of tardigrades has been studied rarely and in the context of oogenesis, functioning of the digestive system, and in the role and function of storage cells. Thus, there are no direct studies on the contribution of the ER in the ability of this organism to cope with environmental stress during cryptobiosis. Nevertheless, it is highly probable that the ER has a crucial role in this uncommon process. Since water bears are easy to handle laboratory animals, they may represent an ideal model organism to uncover the important role of the ER in the cell response to extreme environmental stress conditions.

β-Hairpin Miniprotein Stabilization in Trehalose Glass Is Facilitated by an Emergent Compact Non-Native State

From stem cell freeze-drying to organ storage, considerable recent efforts have been directed toward the development of new preservation technologies. A prominent protein stabilizing strategy involves vitrification in glassy matrices, most notably those formed of sugars such as the biologically relevant preservative trehalose. Here, we compare the folding thermodynamics of a model miniprotein in solution and in the glassy state of the sugars trehalose and glucose. Using synchrotron radiation circular dichroism (SRCD), we find that the same native structure persists in solution and glass. However, upon transition to the glass, a completely different, conformationally restricted unfolded state replaces the disordered denatured state found in solution, potentially inhibiting misfolding. Concomitantly, a large exothermic contribution is observed in glass, exposing the stabilizing effect of interactions with the sugar matrix on the native state. Our results shed light on the mechanism of protein stabilization in sugar glass and should aid in future preservation technologies.

Hydration Layer of Only a Few Molecules Controls Lipid Mobility in Biomimetic Membranes

Self-assembly of biomembranes results from the intricate interactions between water and the lipids’ hydrophilic head groups. Therefore, the lipid–water interplay strongly contributes to modulating membrane architecture, lipid diffusion, and chemical activity. Here, we introduce a new method of obtaining dehydrated, phase-separated, supported lipid bilayers (SLBs) solely by controlling the decrease of their environment’s relative humidity. This facilitates the study of the structure and dynamics of SLBs over a wide range of hydration states. We show that the lipid domain structure of phase-separated SLBs is largely insensitive to the presence of the hydration layer. In stark contrast, lipid mobility is drastically affected by dehydration, showing a 6-fold decrease in lateral diffusion. At the same time, the diffusion activation energy increases approximately 2-fold for the dehydrated membrane. The obtained results, correlated with the hydration structure of a lipid molecule, revealed that about six to seven water molecules directly hydrating the phosphocholine moiety play a pivotal role in modulating lipid diffusion. These findings could provide deeper insights into the fundamental reactions where local dehydration occurs, for instance during cell–cell fusion, and help us better understand the survivability of anhydrobiotic organisms. Finally, the strong dependence of lipid mobility on the number of hydrating water molecules opens up an application potential for SLBs as very precise, nanoscale hydration sensors.

Bioformulation of Silk-Based Coating to Preserve and Deliver Rhizobium tropici to Phaseolus vulgaris Under Saline Environments

Seed priming has been for a long time an efficient application method of biofertilizers and biocontrol agents. Due to the quick degradation of the priming agents, this technique has been limited to specific immediate uses. With the increase of awareness of the importance of sustainable use of biofertilizers, seed coating has presented a competitive advantage regarding its ability to adhere easily to the seed, preserve the inoculant, and decompose in the soil. This study compared primed Phaseolus vulgaris seeds with Rhizobium tropici and trehalose with coated seeds using a silk solution mixed with R. tropici and trehalose. We represented the effect of priming and seed coating on seed germination and the development of seedlings by evaluating physiological and morphological parameters under different salinity levels (0, 20, 50, and 75 mM). Results showed that germination and morphological parameters have been significantly enhanced by applying R. tropici and trehalose. Seedlings of coated seeds show higher root density than the freshly primed seeds and the control. The physiological response has been evaluated through the stomatal conductance, the chlorophyll content, and the total phenolic compounds. The stability of these physiological traits indicated the role of trehalose in the protection of the photosystems of the plant under low and medium salinity levels. R. tropici and trehalose helped the plant mitigate the negative impact of salt stress on all traits. These findings represent an essential contribution to our understanding of stress responses in coated and primed seeds. This knowledge is essential to the design of coating materials optimized for stressed environments. However, further progress in this area of research must anticipate the development of coatings adapted to different stresses using micro and macro elements, bacteria, and fungi with a significant focus on biopolymers for sustainable agriculture and soil microbiome preservation.

Trehalose in pine wood nematode participates in DJ3 formation and confers resistance to low-temperature stress

Background

Recently, pine wood nematode (PWN, Bursaphelenchus xylophilus) has been found in the extreme cold area of northeast China. The third-stage dispersal juvenile (DJ3) of PWN, which is a long-lived stress-resistant stage, plays an important role in the process of PWN spreading to low-temperature areas, as this stage can survive under unfavorable conditions.

Results

Weighted correlation network analysis (WGCNA) was used to analyze the expression patterns of 15,889 genes included in 21 RNA-Seq results of PWN at DJ3 and the other 6 different stages, and a total of 12 coexpression modules were obtained. Among them, the magenta module has the highest correlation with DJ3, which included a total of 652 genes. KEGG enrichment analysis showed that most of the genes in the magenta module were involved in metabolic processes, which were related to autophagy and longevity regulation. These pathways included starch and sucrose metabolism, which contains trehalose metabolism. To explore the function of trehalose in DJ3 formation and survival under − 20 °C, a trehalose-6-phosphate synthase encoding gene (Bx-tps), a trehalose-6-phosphate phosphatase encoding gene (Bx-tpp) and 7 trehalase encoding genes (Bx-tres) were identified and investigated. The expression of these 9 genes was related to the formation of DJ3. A treatment under − 20 °C induced the accumulation of trehalose. The survival rate of DJ3 at -20 °C reduced after silencing of any of these trehalose metabolism genes. Further analysis suggested that two trehalose synthesis genes were highly correlated with DJ3 and might be involved in autophagy by regulating with energy conversion related genes.

Conclusions

The above results indicated that trehalose metabolism promotes DJ3 formation and helps DJ3 survive at -20 °C. Although trehalose accumulation is favorable for DJ3 to cope with low-temperature stress, multiple trehalose metabolism genes need to work together. There may be a multi-path regulated physiological process involving trehalose synthesis genes under low-temperature stress resistance. This physiological process may regulate the formation and maintenance of DJ3 through autophagy and energy conversion.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07839-0.

Increased xerotolerance of Saccharomyces cerevisiae during an osmotic pressure ramp over several generations

Although mechanisms involved in response of Saccharomyces cerevisiae to osmotic challenge are well described for low and sudden stresses, little is known about how cells respond to a gradual increase of the osmotic pressure (reduced water activity; aw ) over several generations as it could encounter during drying in nature or in food processes. Using glycerol as a stressor, we propagated S. cerevisiae through a ramp of the osmotic pressure (up to high molar concentrations to achieve testing-to-destruction) at the rate of 1.5 MPa day-1 from 1.38 to 58.5 MPa (0.990-0.635 aw ). Cultivability (measured at 1.38 MPa and at the harvest osmotic pressure) and glucose consumption compared with the corresponding sudden stress showed that yeasts were able to grow until about 10.5 MPa (0.926 aw ) and to survive until about 58.5 MPa, whereas glucose consumption occurred until 13.5 MPa (about 0.915 aw ). Nevertheless, the ramp conferred an advantage since yeasts harvested at 10.5 and 34.5 MPa (0.778 aw ) showed a greater cultivability than glycerol-shocked cells after a subsequent shock at 200 MPa (0.234 aw ) for 2 days. FTIR analysis revealed structural changes in wall and proteins in the range 1.38-10.5 MPa, which would be likely to be involved in the resistance at extreme osmotic pressure.

Characterization of trehalose-6-phosphate synthase and Na+/H+ antiporter genes in Vuralia turcica and expression analysis under salt and cadmium stresses

Vuralia turcica (Fabaceae; Papilionoideae) is a critically endangered endemic plant species in Turkey. This plant grows naturally in saline environments, although the photosynthesis and physiological functions of many plants are affected by salt stress. Molecular control mechanisms and identification of genes involved in these mechanisms constitute the critical field of study in plant science. Trehalose-6-phosphate synthase (TPS) is one of the essential enzyme genes involved in trehalose biosynthesis, which is protective against salt stress. Also, the vacuolar Na+/H+ antiporter gene (NHX) is known to be useful in salt tolerance. In this study, the TPS and NHX-like genes in V. turcica were partially sequenced using degenerate primers for the first time and submitted to the NCBI database (accession numbers MK120983 and MH757417, respectively). Also, the expression levels of the genes encoding TPS and NHX were investigated. The results indicate that the increase in both the level of applied salt and cadmium is coupled with the increase in the expression level of NHX and TPS genes. However, salt exposure significantly affected the expression level of the NHX gene. The findings suggest that the NHX gene might play a crucial role in the salt tolerance ability of V. turcica.

No water, no mating: Connecting dots from behaviour to pathways

Insects hold considerable ecological and agricultural importance making it vital to understand the factors impacting their reproductive output. Environmental stressors are examples of such factors which have a substantial and significant influence on insect reproductive fitness. Insects are also ectothermic and small in size which makes them even more susceptible to environmental stresses. The present study assesses the consequence of desiccation on the mating latency and copulations duration in tropical Drosophila melanogaster. We tested flies for these reproductive behavioral parameters at varying body water levels and with whole metabolome analysis in order to gain a further understanding of the physiological response to desiccation. Our results showed that the duration of desiccation is positively correlated with mating latency and mating failure, while having no influence on the copulation duration. The metabolomic analysis revealed three biological pathways highly affected by desiccation: starch and sucrose metabolism, galactose metabolism, and phenylalanine, tyrosine and tryptophan biosynthesis. These results are consistent with carbohydrate metabolism providing an energy source in desiccated flies and also suggests that the phenylalanine biosynthesis pathway plays a role in the reproductive fitness of the flies. Desiccation is a common issue with smaller insects, like Drosophila and other tropical insects, and our findings indicate that this lack of ambient water can immediately and drastically affect the insect reproductive behaviour, which becomes more crucial because of unpredictable and dynamic weather conditions.

Impact of crystalline and amorphous matrices on successful spray drying of siRNA polyplexes for inhalation of nano-in-microparticles

To develop stable and inhalable dry powder formulations with long shelf life, we spray dried polyplexes consisting of siRNA and a polyethylenimine based block copolymer in presence of mannitol or trehalose. We investigated the effect of inlet (T-In) and outlet (T-Out) temperature on the recovery of siRNA as well as adsorption effects within the tubing material. Choosing a low abrasion silicon tubing prevented siRNA loss due to adsorption. Mannitol and trehalose formulations preserved siRNA integrity regardless of excipient concentration and temperature at T-Out below the siRNA melting temperature. Trehalose formulations allowed full siRNA recovery whereas mannitol formulations resulted in spray drying induced losses of ~20 % siRNA and of 50-60 % polymer. Mannitol formulations showed optimal aerodynamic characteristics as confirmed by next generation impaction analysis based upon siRNA content. All spray dried formulations resulted in GFP silencing comparable or better than freshly prepared polyplexes. To test if the observed results could be transferred, formulations of siRNA and transferrin-PEI conjugates were spray dried, characterized and used to transfect primary human T cells ex vivo. Results confirmed successful silencing of the Th2 transcription factor GATA3 in primary CD4+ T cells with spray dried formulations as a potential treatment for severe asthma.

Treatment challenges and delivery systems in immunomodulation and probiotic therapies for periodontitis

Introduction: Periodontitis is a widespread illness that arises due to disrupted interplay between the oral microbiota and the host immune response. In some cases, conventional therapies can provide temporary remission, although this is often followed by disease relapse. Recent studies of periodontitis pathology have promoted the development of new therapeutics to improve treatment options, together with local application using advanced drug delivery systems.Areas covered: This paper provides a critical review of the status of current treatment approaches to periodontitis, with a focus on promising immunomodulation and probiotic therapies. These are based on delivery of small molecules, peptides, proteins, DNA or RNA, and probiotics. The key findings on novel treatment strategies and formulation of advanced delivery systems, such as nanoparticles and nanofibers, are highlighted.Expert opinion: Multitarget therapy based on antimicrobial, immunomodulatory, and probiotic active ingredients incorporated into advanced delivery systems for application to the periodontal pocket can improve periodontitis treatment outcomes. Translation of such adjuvant therapy from laboratory to patient is expected in the future.

Uncoupling glucose sensing from GAL metabolism for heterologous lactose fermentation in Saccharomyces cerevisiae

OBJECTIVES

Development of a system for direct lactose to ethanol fermentation provides a market for the massive amounts of underutilized whey permeate made by the dairy industry. For this system, glucose and galactose metabolism were uncoupled in Saccharomyces cerevisiae by deleting two negative regulatory genes, GAL80 and MIG1, and introducing the essential lactose hydrolase LAC4 and lactose transporter LAC12, from the native but inefficient lactose fermenting yeast Kluyveromyces marxianus.

RESULTS

Previously, integration of the LAC4 and LAC12 genes into the MIG1 and NTH1 loci was achieved to construct strain AY-51024M. Low rates of lactose conversion led us to generate the Δmig1Δgal80 diploid mutant strain AY-GM from AY-5, which exhibited loss of diauxic growth and glucose repression, subsequently taking up galactose for consumption at a significantly higher rate and yielding higher ethanol concentrations than strain AY-51024M. Similarly, in cheese whey permeate powder solution (CWPS) during three, repeated, batch processes in a 5L bioreactor containing either 100 g/L or 150 g/L lactose, the lactose uptake and ethanol productivity rates were both significantly greater than that of AY-51024M, while the overall fermentation times were considerably lower.

CONCLUSIONS

Using the Cre-loxp system for deletion of the MIG1 and GAL80 genes to relieve glucose repression, and LAC4 and LAC12 overexpression to increase lactose uptake and conversion provides an efficient basis for yeast fermentation of whey permeate by-product into ethanol.

Creation of a novel lipid-trehalose derivative showing positive interaction with the cell membrane and verification of its cytoprotective effect during cryopreservation

Cryopreservation is important for enabling long-term cell preservation. However, physical damage due to ice crystal formation and membrane permeation by dimethyl sulfoxide (DMSO) severely affects cryopreserved cell viability. To ensure cell survival and functional maintenance after cryopreservation, it is important to protect the cell membrane, the most vulnerable cell component, from freeze-thaw damage. This study aimed to create a glycolipid derivative having a positive interaction with the cell membrane and cytoprotective effects. As a result, we synthesized a novel trehalose derivative, oleyl-trehalose (Oleyl-Treh), composed of trehalose and oleyl groups. Its use led to increased viable cell counts when used with DMSO in a non-cytotoxic concentration range (1.6 nM-16 μM). Oleyl-Treh significantly improved viability and liver-specific functions of hepatocytes after cryopreservation, including albumin secretion, ethoxyresorufin-O-deethylase activity (an indicator of cytochrome P450 family 1 subfamily A member 1 activity), and ammonia metabolism. Oleyl-Treh could localize trehalose to the cell membrane; furthermore, the oleyl group affected cell membrane fluidity and exerted cryoprotective effects. This novel cryoprotective agent, which shows a positive interaction with the cell membrane, provides a unique approach toward cell protection during cryopreservation.

Effect of trehalose on protein cryoprotection: Insights into the mechanism of slowing down of hydration water

We study, with molecular dynamics simulations, a lysozyme protein immersed in a water-trehalose solution upon cooling. The aim is to understand the cryoprotectant role played by this disaccharide through the modifications that it induces on the slow dynamics of protein hydration water with its presence. The α-relaxation shows a fragile to strong crossover about 20° higher than that in the bulk water phase and 15° higher than that in lysozyme hydration water without trehalose. The protein hydration water without trehalose was found to show a second slower relaxation exhibiting a strong to strong crossover coupled with the protein dynamical transition. This slower relaxation time importantly appears enormously slowed down in our cryoprotectant solution. On the other hand, this long-relaxation in the presence of trehalose is also connected with a stronger damping of the protein structural fluctuations than that found when the protein is in contact with the pure hydration water. Therefore, this appears to be the mechanism through which trehalose manifests its cryoprotecting function.

Advanced Nanomaterials-Assisted Cell Cryopreservation: A Mini Review

Cell cryopreservation is of vital significance both for transporting and storing cells before experimental/clinical use. Cryoprotectants (CPAs) are necessary additives in the preserving medium in cryopreservation, preventing cells from freeze-thaw injuries. Traditional organic solvents have been widely used in cell cryopreservation for decades. Given the obvious damage to cells due to their undesirable cytotoxicity and the burdensome post-thaw washing cycles before use, traditional CPAs are more and more likely to be replaced by modern ones with lower toxicity, less processing, and higher efficiency. As materials science thrives, nanomaterials are emerging to serve as potent vehicles for delivering nontoxic CPAs or inherent CPAs comparable to or even superior to conventional ones. This review will introduce some advanced nanomaterials (e.g., organic/inorganic nanoCPAs, nanodelivery systems) utilized for cell cryopreservation, providing broader insights into this developing field.

Optical cryomicroscopy and differential scanning calorimetry of buffer solutions containing cryoprotectants

In the pharmaceutical industry, cryoprotectants are added to buffer formulations to protect the active pharmaceutical ingredient from freeze- and thaw damage. We investigated the freezing and thawing of aqueous sodium citrate buffer with various cryoprotectants, specifically amino acids (cysteine, histidine, arginine, proline and lysine), disaccharides (trehalose and sucrose), polyhydric alcohols (glycerol and mannitol) and surfactants (polysorbate 20 and polysorbate 80). Hereby, we employed optical cryomicroscopy in combination with differential scanning calorimetry in the temperature range to -80 °C. The effect of cryoprotectants on the morphology of the ice crystals, the glass transition temperature and the initial melting temperature is presented. Some of the cryoprotectants have a significant impact on ice crystal size. Disaccharides restrict ice crystal growth, whereas surfactants and glycerol allow ice crystals to increase in size. Cysteine and mannitol cause dehydration after thawing. Either one or two glass transition temperatures were detected, where arginine, surfactants, glycerol, proline and lysine suppress the second, implying a uniform freeze-concentrated solution. The initial melting temperature of pure buffer solution can be shifted up by adding mannitol, both disaccharides and both surfactants; but down by glycerol, proline and lysine.

Sublethal and lethal effects of the imidacloprid on the metabolic characteristics based on high-throughput non-targeted metabolomics in Aphis gossypii Glover

Sublethal effect considered as an emerging factor to assess the environmental risk of insecticides, which can impact the insects on both physiology and behavior. Lethal exposure can be causing near immediate mortality. Pests are inevitably exposed to sublethal and lethal dose in the agroecosystem following application of pesticides. Insecticides, widely used for the control of insect pests, are irreplaceable in insect pest management. The effects of imidacloprid by the method of high-throughput non-targeted metabolomics was investigated in Aphis gossypii Glover exposed to LC₁₀ and LC₉₀ doses of the imidacloprid, and the control group was treated with the same condition without imidacloprid. Pairwise comparisons showed that 111 metabolites changed significantly, 60 in the LC₁₀ group, and 66 in the LC₉₀ group compared to the control group, while only 16 changes in the LC₁₀ were same with that in LC₉₀ group. Among the changed metabolites, a total of 16 metabolites were identified as potential biomarkers, which represented the most influential pathways including glycolysis and gluconeogenesis, alanine, aspartate, and glutamate metabolism, ascorbate and aldarate metabolism, glutathione metabolism, phenylalanine metabolism, tyrosine metabolism, caffeine metabolism and parkinson's disease (PD), which could account for the sublethal and lethal effects on A. gossypii. These modified metabolic pathways demonstrated that high energy consumption, excitotoxicity and oxidative stress (OS) were appeared in both LC₁₀ and LC₉₀ groups, while PD was detected only in the LC₉₀ group. The results of non-targeted metabolomics revealed the effects of neonicotinoid pesticide exposure on A. gossypii successfully, and provided a deep insight into the influenced physiology by the stress of neonicotinoid pesticide in the insect.

The effect of trehalose, antioxidants, and acetate buffer concentration on oxytocin stability

Oxytocin is a cyclic nonapeptide used to induce labor and prevent bleeding after childbirth. Due to its instability, storage and transport of oxytocin formulations can be problematic in hot/tropical climates. The aim of this study was to investigate the effect of trehalose and select antioxidants (uric acid, butylated hydroxytoluene, and l-ascorbic acid) on oxytocin stability in solution. The effect of buffer composition and acetate buffer concentration was also studied. Acetate buffer was found to work better than citrate/phosphate buffer for the oxytocin stability. Lower acetate buffer concentrations (0.025 M or less) were also found to yield improved oxytocin stability compared to higher concentrations. Although known degradation pathways of oxytocin include oxidation, the antioxidants uric acid and butylated hydroxytoluene had negligible effect on the oxytocin stability while l-ascorbic acid led to significantly faster degradation. Despite trehalose's reputation as a great stabilizer for biomolecules, it also had small to negligible effect on oxytocin stability at concentrations up to 1 M in acetate buffer. These results were surprising given the present literature on trehalose as a stabilizer for various biomolecules, including proteins and lipids.

Effect of Methyl-β-Cyclodextrin and Trehalose on the Freeze-Drying and Spray-Drying of Sericin for Cosmetic Purposes

Sericin is a protein extracted from Bombyx mori silk cocoons. Over the last decade, this wastewater product of the textile industry has shown many interesting biological properties. This protein is widely used in the cosmetic and biomedical fields. In this study, sericin has been obtained via a High-Temperature High-Pressure degumming process, and was dried using the freeze-drying (fd) and spray-drying (sd) techniques. Proteins tend to collapse during drying, hence, sericin has been dried in the presence of two selected carrier agents: methyl-β-cyclodextrin and trehalose. The obtained powders have been analyzed using thermal investigation, microscopy (optical, SEM), and granulometric and spectroscopic analyses. Moreover, the percentage yield of the spray-drying process has been calculated. Both the agents were able to significantly improve the drying process, without altering the physico-chemical properties of the protein. In particular, the co-spray-drying of sericin with methyl-β-cyclodextrin and trehalose gave good process yields and furnished a powder with low moisture content and handling properties that are better than those of the other studied dried products. These characteristics seem to be appropriate and fruitful for the manufacturing of cosmetic raw materials.

Effects of glass transition and hydration on the biological stability of dry yeast

The purpose of this study was to determine the effects of glass transition and hydration on the storage stability of baker's dry yeast (Saccharomyces cerevisiae). The glass transition temperature (T_g ) of the yeast decreased with increase in water activity (a_w ), and a_w at which glass transition occurs at 25 °C was determined as the critical a_w (a_wc ). From mechanical relaxation measurements at 25 °C, the yeast exhibited a large mechanical relaxation above the a_wc , and the degree of mechanical relaxation increased gradually with increasing a_w . This behavior corresponded to a gradual increase in molecular mobility with increasing a_w in the rubbery liquid state. Freezable water was observed from a_w ≥0.810, and the proportion of freezable water increased with increasing a_w . Examination of the effect of a_w on the residual biological activity of yeast samples stored at 25 °C for 30 days revealed maximum residual biological activity at a_w  = 0.225 to 0.432. In the lower a_w range, the residual biological activity decreased because of oxidation of lipids. In the higher a_w range, the residual biological activity decreased gradually with increasing a_w . The yeast samples maintained a relatively high residual biological activity, because they could maintain relatively low molecular mobility even in the rubbery liquid state, as suggested by their mechanical relaxation behavior. At a_w ≥0.809, residual activity decreased to a negligible value. This could be explained by the appearance of secondary hydrate water (freezable water). Hydrate water protects yeast cells from lipid oxidation but reduces the T_g . As a result, the yeast cells are stabilized maximally only at the a_wc . PRACTICAL APPLICATION: Although the growth rate of yeast cells becomes negligible below a certain a_w , the biological activity of dry yeast decreases gradually during storage. The fact that dry yeast can be maximally stabilized at the a_wc is practically useful as a criterion for controlling storage stability. In addition, it was found that a remarkable reduction in the molecular mobility, which is otherwise ordinarily increased due to the glass-to-rubber transition, is prevented in yeast. It is possible that the crystallization of amorphous sugar can be prevented by yeast extract. The suggested effect is expected to result in enhanced quality of carbohydrate-based foods.

Lipid Remodeling Confers Osmotic Stress Tolerance to Embryogenic Cells during Cryopreservation

Plant species conservation through cryopreservation using plant vitrification solutions (PVS) is based in empiricism and the mechanisms that confer cell integrity are not well understood. Using ESI-MS/MS analysis and quantification, we generated 12 comparative lipidomics datasets for membranes of embryogenic cells (ECs) of Magnolia officinalis during cryogenic treatments. Each step of the complex PVS-based cryoprotocol had a profoundly different impact on membrane lipid composition. Loading treatment (osmoprotection) remodeled the cell membrane by lipid turnover, between increased phosphatidic acid (PA) and phosphatidylglycerol (PG) and decreased phosphatidylcholine (PC) and phosphatidylethanolamine (PE). The PA increase likely serves as an intermediate for adjustments in lipid metabolism to desiccation stress. Following PVS treatment, lipid levels increased, including PC and PE, and this effectively counteracted the potential for massive loss of lipid species when cryopreservation was implemented in the absence of cryoprotection. The present detailed cryobiotechnology findings suggest that the remodeling of membrane lipids and attenuation of lipid degradation are critical for the successful use of PVS. As lipid metabolism and composition varies with species, these new insights provide a framework for technology development for the preservation of other species at increasing risk of extinction.

Investigating solution effects injury of human T lymphocytes and its prevention during interrupted slow cooling

Cooling rate is a critical parameter affecting the success of cell cryopreservation. Fast cooling can result in intracellular ice formation (IIF), while slow cooling can bring solution effects injury, both are detrimental to the cells. Whilst most of the studies have investigated how IIF affects cells, solution effects injury has received little attention. Here, we studied the solution effects injury of human T lymphocytes by cryomicroscopy and tested the osmoprotective ability of some frequently used cryoprotective agents (CPAs) such as dimethyl sulfoxide (DMSO), glycerol, trehalose, urea and l-proline. We further investigated the relationship between cell volume, latent heat and solution effects cell injury. We found that solution effects injury during interrupted slow cooling was caused by high concentration of the extracellular solution rather than eutectic formation and solutes precipitation. DMSO, glycerol and trehalose can protect cells from solution effects injury, while l-proline and urea cannot under the same condition. The cell volume and latent heat are not crucial for causing solution effects injury in cells. This work confirms that high osmotic pressure, rather than eutectic formation, leads to cell injury. It also suggests that cell volume and latent heat may not be a key factor for explaining solution effects injury and its prevention in the cryopreservation of human T lymphocytes.

The Future of Antifungal Drug Therapy: Novel Compounds and Targets

Fungal infections are a universal problem and are routinely associated with high morbidity and mortality rates in immunocompromised patients. Existing therapies comprise five different classes of antifungal agents, four of which target the synthesis of ergosterol and cell wall glucans. However, the currently available antifungals have many limitations, including poor oral bioavailability, narrow therapeutic indices, and emerging drug resistance resulting from their use, thus making it essential to investigate the development of novel drugs which can overcome these limitations and add to the antifungal armamentarium. Advances have been made in antifungal drug discovery research and development over the past few years as evidenced by the presence of several new compounds currently in various stages of development. In the following minireview, we provide a comprehensive summary of compounds aimed at one or more novel molecular targets. We also briefly describe potential pathways relevant for fungal pathogenesis that can be considered for drug development in the near future.

Fine-tuned dehydration by trehalose enables the cryopreservation of RBCs with unusually low concentrations of glycerol

We regulated the amount of trehalose and combined it with glycerol to achieve unusually low glycerol concentrations in the cryopreservation of RBCs compared with traditional methods.

Dehydrated Caenorhabditis elegans Stocks Are Resistant to Multiple Freeze-Thaw Cycles

Ultracold preservation is widely used for storage of genetic stocks of Caenorhabditis elegans. Current cryopreservation protocols are vulnerable to refrigeration failures, which can result in the loss of stock viability due to damage during re-freezing. Here we present a method for preserving worms in a dehydrated and frozen form that retains viability after multiple freeze-thaw cycles. After dehydration in the presence of trehalose or glycerol, C. elegans stocks can be frozen and thawed multiple times while maintaining viability. While both dauer and non-dauer larvae survive desiccation and freezing, the dauer defective mutant daf-16 does not survive desiccation. Our technique is useful for storing stocks in a manner robust to freezer failures, and potentially for shipping strains between laboratories.