Low-temperature Adaptation Research Articles

Construction of environmentally stable self-adhesive conductive cellulose hydrogel for electronic skin sensor via autocatalytic fast polymerization strategy at room temperature.

Bio-based conductive hydrogels are catching a widespread attention in the field of flexible sensors and human-machine interface interaction. Here, an enhanced autocatalytic system constructed from dopamine-encapsulated cellulose nanofibers (DA@CNF) and Cu2+ in a glycerol-water binary solvent achieved fast auto-polymerization of hydrogels within 60s. X-ray photoelectron spectra (XPS), UV-vis spectrum (UV), Cyclic Voltammetry (CV) and electron paramagnetic resonance (EPR) were used to characterize the autocatalytic system. The hydrogel obtained has excellent mechanical properties (strain >900%, compressive strength >800kPa, toughness >700kJ/m3), reproducible adhesive properties (>10 times), excellent high and low temperature (-20-60°C) adaptability and stability. And the excellent electrical conductivity endows the hydrogel with high strain sensitivity (GF=5.15) over a wide strain range (400%). The excellent overall performance ensures the stability and accuracy of the hydrogel as a flexible electronic skin for signal detection during human-computer interface interaction. This work contributes a new research strategy for the rational design and green development of biomass-based conductive hydrogel sensors.

Physiological and molecular regulatory mechanism of flavonoid metabolite biosynthesis during low temperature adaptation in Lavandula angustifolia Mill.

BackgroundLavandula angustifolia Mill., a valuable aromatic plant, often encounters low temperature stress during its growth in Northeast China. Understanding the mechanisms behind its resistance to low temperatures is essential for enhancing this trait. Flavonoids play a vital role as stress-resistant compounds, significantly contributing to plants’ responses to low-temperature stress. However, the molecular mechanism governing flavonoid biosynthesis in L. angustifolia under low-temperature stress is remains inadequately understood.ResultsIn this study, the physiological indexes, metabolome, and transcriptome of L. angustifolia were studied under temperatures of 30 °C, 20 °C, 10 °C, and 0 °C. The activities of peroxidase (POD) and superoxide dismutase (SOD) were notably the highest at 0 ℃, demonstrating optimal scavenging of reactive oxygen species (ROS). Among the 1150 metabolites analyzed, 52 flavonoid differential expression metabolites (DEMs) significantly increased at 10 °C and 0 °C. Furthermore, 55 differential expression genes (DEGs) involved in the flavonoid biosynthesis pathway showed significant up-regulation as the temperature dropped from 30 °C to 0 °C, indicating their role in positively regulating flavonoid biosynthesis under low temperatures. The flavonoid biosynthetic pathway was established based on key DEGs, including LaPAL-5, LaPAL-11, LaC4H-2, LaHCT, LaC3’H-4, LaCHS, LaF3PH-3, LaCCoAOMT-2, LaCCoAOMT-3, and LaDFR. Conserved domains predicted in 10 key proteins were identified as being responsible for catalytic functions that promote flavonoid biosynthesis under low temperatures. The synergistic enhancement between flavonoid DEMs and antioxidant enzymes was found to significantly contribute to the cold resistance of L.angustifolia.ConclusionsThe findings of this study provide a valuable reference for understanding the molecular regulation of L. angustifolia in response to low temperatures, laying a crucial foundation for future molecular breeding efforts aimed at developing cold-resistant varieties.

Novel Multipoint-drive Rotary Actuator for Extraterrestrial Celestial Ultrasonic Driller

Ultrasonic drilling has emerged as a prominent technique in extraterrestrial environments due to its advantageous features. However, its application in extraterrestrial sampling missions is constrained by challenges such as drilling, chip removal efficiency, and high and low temperature adaptability. Addressing these limitations, this study introduces a novel multi-point driven rotary helical longitudinal torsion horn. The initial phase involved a detailed analysis of the actuator’s structure and operational principle. Subsequently, the actuator’s vibration mode and elliptical motion trajectory were validated through finite element simulation. The study further explores a methodology for adjusting the parameters of the helical groove and the displacement amplitude of the impact head. Following the theoretical analysis, prototypes of the actuator and drill were fabricated. Their adaptability to high and low temperatures, as well as their output characteristics, were rigorously tested. Experimental results demonstrate that with an increase in temperature, the dynamic impedance of the actuator initially rises before decreasing, while the mechanical quality factor exhibits the opposite trend. Notably, the concurrent activation of points P1 and P2 significantly enhances the no-load speed, achieving a maximum of 506 revolutions per minute (r/min). Under conditions of power below 35 W and a drilling pressure of 10 N, the drilling speed achieved in basalt is 6.2 millimeters per minute (mm/min). The proposed multipoint-driven actuator can effectively improve the drilling and chip removal efficiency of the driller, which is an important application prospect in future extraterrestrial drilling missions.

Lignocellulose degradation and temperature adaptation mechanisms during composting of mushroom residue and wood chips at low temperature with inoculation of psychrotolerant microbial agent

Low ambient temperature become the limiting factor of composting in cold regions, thus hindering the recycle of agricultural and forestry wastes. In this study, the composting of mushroom residue and wood chips (MRWC) under low temperature was successfully implemented with inoculation of psychrotolerant cellulolytic microbial agent. Composting entered thermophilic stage on third day and the peak temperature reached to 66.25 °C. After 84 days of composting, the degradation rate of cellulose and hemicellulose was 40.85% and 100%, respectively and the compost product was completely mature and met the requirements of organic fertilizer. Metagenomic and transcriptome sequencing were applied to reveal the microbial composition and their substrates conversion functions and adaptation mechanisms through low to high temperatures. Streptomyces, Mesorhizobium, Devosia, Aspergillus and Mucor were dominant genera in the microbial community that were rich in genes of lignocellulose degradation. Various genes related to low temperature adaptation (fatty acid, trehalose, mannitol, betaine metabolism and cold shock mechanism) and high temperature tolerance (heat shock and antioxidant) were detected during MRWC composting. These results indicated that microbes during composting constituted a high-efficiency lignocellulosic ultilization system in cold conditions. Besides, the microbes of microbial agent, especially Streptomyces and Aspergillus, possessed numerous genes involving in lignocellulose degradation and temperature adaptation and quite different temperature response patterns were found to perform in bacteria and fungi. The transcription levels of most these genes in Aspergillus exhibited significant differences under different substrates and temperature conditions, suggesting that the inoculum was crucial to the composting process and beneficial to maintain the temperature of piles. This study demonstrated that the application of psychrotolerant microbes was a promising strategy to increase the efficiency of composting in cold regions and these results could also provided the guidance for optimizing microbial agent.

Quantification of solvent-mediated host-ion interaction in graphite intercalation compounds for extreme-condition Li-ion batteries

Achieving simultaneous fast-charging capabilities and low-temperature adaptability in graphite-based lithium-ion batteries (LIBs) with an acceptable cycle life remains challenging. Herein, an ether-based electrolyte with temperature-adaptive Li+ solvation structure is designed for graphite, and stable Li+/solvent co-intercalation has been achieved at subzero. As revealed by in-situ variable temperature (−20 °C) X-ray diffraction (XRD), the poor compatibility of graphite in ether-based electrolyte at 25 °C is mainly due to the continuous electrolyte decomposition and the in-plane rearrangement below 0.5 V. Former results in a significant irreversible capacity, while latter maintains graphite in a prolonged state of extreme expansion, ultimately leading to its exfoliation and failure. In contrast, low temperature triggers the rearrangement of Li+ solvation structure with stronger Li+/solvent binding energy and shorter Li+–O bond length, which is conducive for reversible Li+/solvent co-intercalation and reducing the time of graphite in an extreme expansion state. In addition, the co-intercalation of solvents minimizes the interaction between Li-ions and host graphite, endowing graphite with fast diffusion kinetics. As expected, the graphite anode delivers about 84% of the capacity at room temperature at −20 °C. Moreover, within 6 min, about 83%, 73%, and 43% of the capacity could be charged at 25, −20, and −40 °C, respectively.

State of the art on solid–gas sorption based long-term thermochemical energy storage

Solid-gas sorption thermochemical heat storage technology is an innovative and promising solution for storing heat over long periods. The review focuses on the construction of composite sorption thermochemical heat storage materials and binary mixed salt materials with porous matrix as the supporting materials, which can further improve the hydration rate and cycle stability of single hydrated salt. Furthermore, the heat storage capabilities of the metal halide/ammonia working pair make it suitable for extreme environments, surpassing the limitations of water-based working pairs in terms of low-temperature adaptability. It is worth noting that common solid–gas reactors and measures to enhance heat and mass transfer are also reviewed. Meanwhile, the efficient open and closed heat storage systems and their optimization schemes are introduced, and the feasibility of the practical operation of the heat storage systems is evaluated comprehensively from the technical and economic perspectives, and the future research challenges are prospected.

The effect of temperature and breathing pattern on the surface activity of ground squirrel pulmonary surfactant.

This study investigates how hibernation affects the surface activity of pulmonary surfactant with respect to temperature and breathing pattern. Surfactant was isolated from a hibernating species, the 13-lined ground squirrel, and a homeotherm, the rabbit, and analysed for biophysical properties on a constrained sessile drop surfactometer. The results showed that surfactant from ground squirrels reduced surface tension better at low temperatures, including when mimicking episodic breathing, as compared with rabbit surfactant. In addition, low temperature adaptation was also observed using only the hydrophobic components of surfactant from ground squirrels. Overall, the data support the conclusion that ground squirrel surfactant has adapted to maintain surface activity during low temperature episodic breathing patterns, and that temperature adaptation is maintained with the hydrophobic components of the surfactant.

Reconstructing Helmholtz Plane Enables Robust F-Rich Interface for Long-Life and High-Safe Sodium-Ion Batteries.

Hard carbon (HC) is the most commonly used anode material in sodium-ion batteries. However, the solid-electrolyte-interface (SEI) layer formed in carbonate ester-based electrolytes has an imperceptible dissolution tendency and a sluggish Na+ diffusion kinetics, resulting in an unsatisfactory performance of HC anode. Given that electrode/electrolyte interface property is highly dependent on the configuration of Helmholtz plane, we filtrated proper solvents by PFBE (PF6 - anion binding energy) and CAE (carbon absorption energy) and disclosed the function of chosen TFEP to reconstruct the Helmholtz plane and regulate the SEI film on HC anode. Benefiting from the preferential adsorption tendency on HC surface and strong anion-dragging interaction of TFEP, a robust and thin anion-derived F-rich SEI film is established, which greatly enhances the mechanical stability and the Na+ ion diffusion kinetics of the electrode/electrolyte interface. The rationally designed TFEP-based electrolyte endows Na||HC half-cell and 2.8 Ah HC||Na4Fe3(PO4)2P2O7 pouch cell with excellent rate capability, long cycle life, high safety and low-temperature adaptability. It is believed that this insightful recognition of tuning interface properties will pave a new avenue in the design of compatible electrolyte for low-cost, long-life, and high-safe sodium-ion batteries.

Transcriptional dynamic changes in energy metabolism, protein synthesis and cell cycle regulation reveal the biological adaptation mechanisms of juvenile Acrossocheilus wenchowensis under acute temperature changes

In recent years, frequent acute temperature changes have posed a serious threat to the physiology and survival of fish. This study utilized RNA-Seq technology to analyze the transcriptional dynamics in the muscle tissues of Acrossocheilus wenchowensis under various acute temperature conditions (16◦C, 20◦C, 24◦C, 28◦C and 32◦C). Through comprehensive analysis, we identified 11509 differentially expressed genes (DEGs), a gene set (profiles 19) that was significantly up-regulated with increasing temperature, and two weighted gene co-expression network analysis (WGCNA) modules that were significantly correlated with acute temperature changes. Furthermore, we identified 28 transcription factors that are pivotal in oxidative stress and energy metabolism under acute temperature changes. Our results showed that, compared to the control group (24°C), KEGG functional enrichment analysis revealed significant enrichment of DEGs in the cell cycle, DNA replication, and p53 signaling pathway, with an overall trend of suppressed expression. This indicates that maintaining cell stability and reducing cell damage is an effective adaptive mechanism for A. wenchowensis to cope with acute temperature changes. Through STEM analysis and the black WGCNA module associated with high-temperature stress, we identified significant up-regulation of pathways and hub genes related to energy metabolism including oxidative phosphorylation, TCA cycle, purine metabolism, and glutathione metabolism, as well as the central roles of signal transduction pathways such as MAPK signaling pathway and AMPK signaling pathway, which synergistically regulate energy production. Under acute low-temperature stress, the turquoise WGCNA module highlighted significant up-regulation of hub genes associated with Ribosomal and Spliceosomal pathways related to protein synthesis and processing, as well as activation of calcium signaling pathways, which plays an important role in maintaining cellular function during low-temperature adaptation. These findings provide a critical theoretical and molecular basis for the adaptation of eurythermal fish to rapid temperature changes.

Glycerol Metabolism is Important for the Low-Temperature Adaptation of a Global Quarantine Pest Anoplophora glabripennis Larvae.

Anoplophora glabripennis is a critical global quarantine pest. Recently, its distribution has been extended to colder and higher-latitude regions. The adaptation to low temperatures is vital for the successful colonization of insects in new environments. However, the metabolic pathways of A. glabripennis larvae under cold stress remain undefined. This study analyzed the larval hemolymph under different low-temperature treatments using LC-MS/MS. The results showed that differential metabolites associated with sugar and lipid metabolism are pivotal in the larval chill coma process. Under low-temperature treatments, the glycerol content increased significantly compared with the control group. Cold stress significantly induced the expression of AglaGK2 and AglaGPDHs. After undergoing RNAi treatment for 48 h, larvae exposed to -20 °C for 1 h showed reduced recovery when injected with ds-AglaGK2 and ds-AglaGPDH1 compared to the control group, indicating that glycerol biosynthesis plays a role in the low-temperature adaptation of A. glabripennis larvae. Our results provide a theoretical basis for clarifying the molecular mechanism of A. glabripennis larvae in response to environmental stresses.

Differential analysis of transcriptome of psychrophilic bacteria under different culture temperatures.

Psychrophilic bacteria can survive in a unique living environment. To explore the mechanism of low temperature adaptation and the physiological function of thermophilic metabolic genes. Serratia marcescens strain F13 stored in microbial laboratory was cultured at 5∘C, 10∘C and 25∘C respectively, and the obtained strains were sequenced by high-throughput transcriptome. Serratia marcescens strain CAV1761 was used as the reference strain. The data produced by transcriptome sequencing were statistically analyzed by biostatistics software such as soapnuke, soap and edger. The differentially expressed genes were found based on the gene expression, and analyzed by Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. The results showed that there were 718 differential genes in F13-10 vs F13-5 comparison group, 1614 differential genes in F13-25 vs F13-5 comparison group and 1636 differential genes in F13-25 vs F13-10 comparison group. GO function enrichment analysis showed that the GO term mainly enriched by different genes in the three comparison groups was mostly related to the migration and transport of cellular or subcellular components, cell localization and transmembrane transporter activity, as well as cilia or flagella dependent cell movement. In the enrichment analysis of KEGG pathway, the three comparison groups all enriched the largest number of differential genes in the branch pathway of KEGG metabolism, followed by the branch pathway of environmental information processing. In F13-10 vs F13-5, the differential genes were mainly concentrated in 20 pathways such as ATP-binding cassette transport (ABC) transporters, thiamine metabolism and flagella assembly; In F13-25 vs F13-5, the differential genes are mainly concentrated in 20 pathways, such as (ABC) transporters, arginine and proline metabolism, two-component system and so on; In F13-25 vs F13-10, the differential genes are mainly concentrated in 20 pathways such as various types of glycan synthesis, two-component system and arginine metabolism.

Regulatory mechanism of cold-inducible diapause in Caenorhabditis elegans

Temperature is a critical environmental cue that controls the development and lifespan of many animal species; however, mechanisms underlying low-temperature adaptation are poorly understood. Here, we describe cold-inducible diapause (CID), another type of diapause induced by low temperatures in Caenorhabditis elegans. A premature stop codon in heat shock factor 1 (hsf-1) triggers entry into CID at 9 °C, whereas wild-type animals enter CID at 4 °C. Furthermore, both wild-type and hsf-1(sy441) mutant animals undergoing CID can survive for weeks, and resume growth at 20 °C. Using epistasis analysis, we demonstrate that neural signalling pathways, namely tyraminergic and neuromedin U signalling, regulate entry into CID of the hsf-1 mutant. Overexpression of anti-ageing genes, such as hsf-1, XBP1/xbp-1, FOXO/daf-16, Nrf2/skn-1, and TFEB/hlh-30, also inhibits CID entry of the hsf-1 mutant. Based on these findings, we hypothesise that regulators of the hsf-1 mutant CID may impact longevity, and successfully isolate 16 long-lived mutants among 49 non-CID mutants via genetic screening. Furthermore, we demonstrate that the nonsense mutation of MED23/sur-2 prevents CID entry of the hsf-1(sy441) mutant and extends lifespan. Thus, CID is a powerful model to investigate neural networks involving cold acclimation and to explore new ageing mechanisms.

Epigenomic features associated with body temperature stabilize tissues during cold exposure in cold-resistant pigs

Cold stress in low-temperature environments can trigger changes in gene expression, but epigenomics regulation of temperature stability in vital tissues, including the fat and diencephalon, is still unclear. Here, we explore the cold-induced changes in epigenomic features in the diencephalon and fat tissues of two cold-resistant Chinese pig breeds, Min and Enshi black (ES) pigs, utilizing H3K27ac CUT&Tag, RNA-seq, and selective signature analysis. Our results show significant alterations in H3K27ac modifications in the diencephalon of Min pigs and the fat of ES pigs after cold exposure. Dramatic changes in H3K27ac modifications in the diencephalon of Min pig are primarily associated with genes involved in energy metabolism and hormone regulation, whereas those in the fat of ES pig are primarily associated with immunity-related genes. Moreover, transcription factors PRDM1 and HSF1, which show evidence of selection, are enriched in genomic regions presenting cold-responsive alterations in H3K27ac modification in the Min pig diencephalon and ES pig fat, respectively. Our results indicate the diversity of epigenomic response mechanisms to cold exposure between Min and ES pigs, providing unique epigenetic resources for studies of low-temperature adaptation in large mammals.

Physiological Response to Low-Temperature Stress and Cold Resistance Evaluation of Ziziphus jujuba var. spinosa Clones from Different Provenances

To investigate the low-temperature adaptability of different provenances of Ziziphus jujuba var. spinosa, we used 21 clones from seven provenances as experimental materials and observed the changes in physiological and biochemical indicators and the characteristics of anatomical structures under low-temperature stress. A comprehensive evaluation of their cold resistance was conducted using the membership function method. As the temperature decreased, the relative electrical conductivity (REC) of clone 89 became stable and had the lowest LT50 value (−44.04 °C). The cold-resistant Z. jujuba var. spinosa had a higher bound water/free water (BW/FW) ratio and antioxidant enzyme activity and accumulated large quantities of osmotic regulatory substances. Higher xylem, phloem, and xylem–cortex ratios and greater conduit density enhanced the cold resistance of Z. jujuba var. spinosa. The membership function values of clones 89, 90, 91, 604, and 612 were greater than 0.6, indicating that they could be evaluated as resources with the potential for low-temperature resistance. The cold resistance rankings for the different provenances were as follows: Kazuo, Liaoning > Jiaxian, Shaanxi > Fuxing, Heibei > Changqing, Shandong > Neiqiu, Heibei > Yanchuan, Shaanxi > Xiaxian, Shanxi. These results provide a scientific basis for the rapid and accurate identification of cold resistance in Z. jujuba var. spinosa resources and the breeding and cultivation of new cold-resistant varieties of this subspecies.

Nitrogen-bridged Cu-Zn dual-atom cooperative interface sites for efficient oxygen reduction reaction in Zn-air battery

Developing nonprecious catalysts with excellent behaviors for oxygen reduction reaction (ORR) has assumed considerable importance, but remains an arduous issue. Herein, we demonstrate a Kirkendall effect-pyrolysis (KEP) strategy to construct N-bridged Cu-Zn dual-atom supported on hollow N-doped carbon (Cu-Zn DA/HNC) for ORR. The hollow structure of N-doped carbon facilitates mass transfer and exposes more actives. What’s more, the shared N atom between Cu and Zn atoms is beneficial to enhance their synergetic effect, creating an appropriately enhanced O* binding. The resulting Cu-Zn DA/HNC displays excellent ORR activity in an alkaline electrolyte, following a nearly four-electron pathway of ORR. Even employing Cu-Zn DA/HNC as the cathode in ZABs, Cu-Zn DA/HNC presents a long cycling life up to 910 h and robust low-temperature adaptability. The facile and straightforward fabrication plus the outstanding ORR performance of Cu-Zn DA/HNC endows its great potential as a significant candidate in practical applications of ZAB.

Transcriptome: New perspective for the rational planting of Dendrobium nobile and the improvement of medicinal quality through cold stimulation

Temperature affects the growth and accumulation of carbohydrate in plants. To study the response of Dendrobium nobile to cold stimulation, by using room temperature as the control, four low-temperature gradients (8 °C, 4 °C, 0 °C, −4 °C) were set to investigate the physiological changes and polysaccharide content of D. nobile. The results showed that under −4 °C treatment, the plant suffered severe damage and normal physiological activities were inhibited, resulting in inability to grow normally. Meanwhile, treatment at 0 °C for 4 d significantly increased the accumulation of polysaccharides in D. nobile (an increase of 56.18 % compared to CK), and the plant can grow normally after relieving cold stimulation. To explore the mechanism of its promoting polysaccharide accumulation, we conducted transcriptome analysis of D. nobile in this treatment. The results showed that TPP6, DPE1, PGMP, BAM3 genes in the starch and subcrosse metropolis; The pel gene in pentose and glucose conversions and transcription factors such as bHLH, MYB, and WRKY were significantly upregulated, thereby promoting the accumulation of polysaccharides in D. nobile. This study provides new perspective into the low-temperature adaptability of D. nobile and lays the foundation for further research on the biosynthetic pathways of D. nobile polysaccharides.

Ethyl fluoroacetate with weak Li+ interaction and high oxidation resistant induced low-temperature and high-voltage graphite//LiCoO2 batteries

Lithium-ion batteries (LIBs) operating at low temperature has always been a significant challenge. In this work, Ethyl fluoroacetate (EFA) was utilized as a single solvent to design a low-temperature electrolyte (LTE). The weak Li+-solvent interaction facilitates fast de-solvation process and improved low-temperature performance, while the high oxidation resistance and fluorine-rich electrolyte/electrolyte interface induced by the fluorinated groups enables wide operating voltage and stable cycling of the LIBs. The EFA-based electrolyte endows the high-voltage (4.45 V) Graphite//LiCoO2 pouch cell with prominent low-temperature adaptability (89.7 % capacity retention retains at −40 °C, and capable of charging at −20 °C) and outstanding cycling performance (87.7 % capacity retention after 400 cycles). This work sheds light on the design of high-voltage and low-temperature electrolytes for lithium-ion batteries.

Haplotype-resolved genome of Prunus zhengheensis provides insight into its evolution and low temperature adaptation in apricot.

Prunus zhengheensis, an extremely rare population of apricots, originated in warm South-East China and is an excellent material for genetic breeding. However, most apricots and two related species (P. sibirica, P. mandshurica) are found in the cold northern regions in China and the mechanism of their distribution is still unclear. In addition, the classification status of P. zhengheensis is controversial. Thus, we generated a high-quality haplotype-resolved genome for P. zhengheensis, exploring key genetic variations in its adaptation and the causes of phylogenetic incongruence. We found extensive phylogenetic discordances between the nuclear and organelle phylogenies of P. zhengheensis, which could be explained by incomplete lineage sorting. A 242.22-Mb pan-genome of the Armeniaca section was developed with 13 chromosomal genomes. Importantly, we identified a 566-bp insertion in the promoter of the HSFA1d gene in apricot and showed that the activity of the HSFA1d promoter increased under low temperatures. In addition, HSFA1d overexpression in Arabidopsis thaliana indicated that HSFA1d positively regulated plant growth under chilling. Therefore, we hypothesized that the insertion in the promoter of HSFA1d in apricot improved its low-temperature adaptation, allowing it to thrive in relatively cold locations. The findings help explain the weather adaptability of Armeniaca plants.

Transcriptomic analysis of cold stress-response in Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae)

Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae) is a solitary ectoparasitoid that parasitizes several stored product beetles. Implementing an effective cold storage program can extend the shelf life of parasitoids for large scale applications in biological control. To explore the low temperature adaptation mechanisms of A. calandrae, the survival, longevity, parasitism rate, fecundity, and transcriptome of cold-treated A. calandrae adults were investigated. Storing A. calandrae adult wasps at 15 °C and 10 °C for 1 week had no significant difference in terms of adult longevity, parasitism rate, and progeny compared with the control. By analysing the gene expression patterns and comparing the whole transcriptome of cold-treated A. calandrae adults (adults after cold storage at 15, 10, or 5 °C for 1 week, referred to as T2, T3, and T4, respectively, and adults without experiencing cold storage referred to as T1), a total of 1376, 9799, and 7745 differentially expressed genes (DEGs) were respectively identified (T1 vs T2, T1 vs T3, T1 vs T4). A total of 196 commonly up-regulated genes and 100 commonly down-regulated genes in T1 vs T2, T1 vs T3, and T1 vs T4 treatments were identified. A total of 6 modules composed of differentially co-expressed genes were identified by weighted gene co-expression network analysis (WGCNA). The Mebrown module was extremely associated with the T4 sample. Mebrown module of genes was found to be highly correlated with the metabolic process (217 genes), cell part (148 genes), and catalytic activity (225 genes). Four transcription factor genes, LOC111691805, LOC126386779, LOC108733382, and LOC108906572 were presented in Mebrown module as hub genes. The changes in gene expression indicated that A. calandrae can significantly upregulate the expression levels of abiotic related genes, such as the heat shock protein (Hsp 90) gene, cytochrome P450, and calnexin gene, etc., to cope with cold stress. The current results provide the molecular mechanisms and identify the key genes that may explain the adaptation of A. calandrae to cold stress.

An aquaporin and an aquaglyceroporin have roles in low temperature adaptation of mosquitoes (Anopheles sinensis).

Mosquitoes (Anopheles sinensis), widely geographically distributed in Asia including China, are the primary vector of the malaria parasite Plasmodium vivax and other parasitic diseases such as Malayan filariasis. An. sinensis can survive through low winter temperatures. Aquaporin channels are found in all life forms, where they facilitate environmental adaptation by allowing rapid trans-cellular movement of water (classical aquaporins) or water and solutes such as glycerol (aquaglyceroporins). Here, we identified and characterized 2 aquaporin (AQP) homologs in An. sinensis: AsAQP2 (An. sinensis aquaglyceroporin) and AsAQP4 (An. sinensis aquaporin). When expressed in frog (Xenopus laevis) oocytes, AsAQP2 transported water, glycerol, and urea; AsAQP4 transported only water. Water permeation through AsAQP2 and AsAQP4 was inhibited by mercuric chloride. AsAQP2 expression was slightly higher in adult female mosquitoes than in males, and AsAQP4 expression was significantly higher in adult males. The 2 AsAQPs were highly expressed in Malpighian tubules and midgut. AsAQP2 and AsAQP4 expression was up-regulated by blood feeding compared with sugar feeding. At freezing point (0°C), the AsAQP4 expression level increased and An. sinensis survival time reduced compared with those at normal temperature (26°C). At low temperature (8°C), the AsAQP2 and AsAQP4 expression levels decreased and survival time was significantly longer compared with those at 26°C. These results suggest that AsAQP2 and AsAQP4 have roles in water homeostasis during blood digestion and in low temperature adaptation of A. sinensis. Together, our results show that the 2 AQPs are important for mosquito diuresis after blood feeding and when exposed to low temperatures.