Variations of body mass and thermogenesis properties in Eothenomys olitor during cold acclimatization

The set-point hypothesis states that there is a biological control method in mammals that actively regulates weight toward a predetermined set weight for each individual, which may occur by regulation of energy intake or energy expenditure. In order to investigate the effects of low temperature on body mass regulation in Eothenomys olitor, body mass, body fat mass, food intake, resting metabolic rate (RMR), non-shivering thermogenesis (NST), serum leptin levels, morphology, biochemical indexes of liver and brown adipose tissue (BAT) and hypothalamic neuropeptide genes expression were measured during cold acclimatization. The results showed that there was no significant difference in body mass, but food intake, RMR and NST increased during cold acclimatization. Cytochrome c oxidase (COX) and α-glycerophosphate oxidase (α-GPO) activities in liver and BAT were significantly enhanced during cold acclimatization, and triiodothyronine (T3) and thyroxine (T4) levels in serum were significantly higher than those in the control group. Serum leptin levels decreased after cold acclimatization. Low temperature significantly increased the expression of neuropeptide Y (NPY) and agouti-related peptide (AgRP), while it decreased cocaine- and amphetamine-regulated transcript peptide (CART) and pro-opiomelanocortin (POMC) expressions. All of the above results suggested that body mass in E. olitor can remain relatively stable at low temperature, which conforms to the ‘set-point hypothesis’. However, the species showed differences with sympatric species, such as E. miletus, Apodemus chevrieri and Tupaia belangeri. Moreover, E. olitor can cope with low temperature by increasing its metabolic rate and thermogenesis properties.

Metabolomic Analysis Reveals Changes in Plasma Metabolites in Response to Acute Cold Stress and Their Relationships to Metabolic Health in Cold-Acclimatized Humans

Cold exposure results in activation of metabolic processes required for fueling thermogenesis, potentially promoting improved metabolic health. However, the metabolic complexity underlying this process is not completely understood. We aimed to analyze changes in plasma metabolites related to acute cold exposure and their relationship to cold-acclimatization level and metabolic health in cold-acclimatized humans. Blood samples were obtained before and acutely after 10–15 min of ice-water swimming (<5 °C) from 14 ice-water swimmers. Using mass spectrometry, 973 plasma metabolites were measured. Ice-water swimming induced acute changes in 70 metabolites. Pathways related to amino acid metabolism were the most cold-affected and cold-induced changes in several amino acids correlated with cold-acclimatization level and/or metabolic health markers, including atherogenic lipid profile or insulin resistance. Metabolites correlating with cold-acclimatization level were enriched in the linoleic/α-linolenic acid metabolic pathway. N-lactoyl-tryptophan correlated with both cold-acclimatization level and cold-induced changes in thyroid and parathyroid hormones. Acute cold stress in cold-acclimatized humans induces changes in plasma metabolome that involve amino acids metabolism, while the linoleic and α-linolenic acid metabolism pathway seems to be affected by regular cold exposure. Metabolites related to metabolic health, thermogenic hormonal regulators and acclimatization level might represent prospective molecular factors important in metabolic adaptations to regular cold exposure.

Differences in Early Season Emergence and Reproductive Activity Between Spathius agrili (Hymenoptera: Braconidae) and Spathius galinae, Larval Parasitoids of the Invasive Emerald Ash Borer (Coleoptera: Buprestidae)

Both Spathius agrili Yang and Spathius galinae Belokobylskij and Strazanac are host-specific parasitic wasps introduced for biological control of emerald ash borer in North America. Spathius agrili is native to northeastern China and S. galinae comes from a more northern, colder climate in the Russian Far East. Their origin may lead to differing abilities to adapt to climate and their host in North America. We conducted both field and laboratory experiments to determine the timing of early season emergence and synchronization of each parasitoid species to their host in the United States, and if manipulating prerelease conditions could affect emergence time. A cold acclimatization treatment prior to parasitoid emergence was assessed and compared with untreated control group reared with standard rearing protocols. Stands of naturally emerald ash borer-infested ash were sampled at two locations in Virginia throughout the experiment to determine when the parasitoid-susceptible life stage (third to fourth instar) occurred. Untreated S. galinae emerged approximately 2 wk earlier than any other cohort, whereas cold acclimatized S. galinae emerged later than any other cohort. Emergence time of S. agrili was unaffected by cold acclimatization. Cold acclimatization treatment did not affect the parasitism rate of either species, nor did it have multigenerational effects. Emergence time of the subsequent generation of S. agrili was delayed by cold acclimatization treatment, whereas S. galinae experienced no multigenerational effects. At Virginia field sites, susceptible EAB larvae were present during the emergence time of all four groups of parasitoids. Untreated S. galinae had the least overlap with any susceptible EAB larvae.

PO-073 The influence of cold acclimatization training on plasma NO and NOS contents in recruits

Objective To observe the influence of cold acclimatization training on plasma NO and NOS contents in recruits, so as to provide basis for further study of cold acclimatization mechanism and training methods. Methods 50 new recruits in cold regions were chosen as study objects，were divided randomly into two groups. Control group did normal exercise, the experimental group was trained according to the cold acclimatization training plan. The content of NO and NOS in the blood plasma were detected respectively before training and 30 days after training． Results Comparison between after training and before training，the content of plasma NO in experimental group increased very significantly (P<0.01), and the content of plasma NOS decreased very significantly (P<0.01)after training. The content of plasma NO in the control group was significantly higher than that before training (P<0.05), and the content of plasma NOS was significantly lower than that before training (P<0.05). Comparison of two groups after training，the plasma NO content of the experimental group was higher than that of the control group, and the plasma NOS content was significantly lower than that of the control group (P < 0.05). Conclusions The local cold stimulation combined with the extension of outdoor exercise time can promote the changes in the content of NO and NOS, so as to adjust the vasoconstriction and make the body adaptable to the cold.

Trans-Ferulic Acid-4-β-Glucoside Alleviates Cold-Induced Oxidative Stress and Promotes Cold Tolerance

Trans-ferulic acid-4-β-glucoside (C16H20O9, TFA-4β-G) is a monomer extracted from the Chinese medicine called radix aconiti carmichaeli (Fuzi). To date, research on this substance is lacking. Here, we found that trans-ferulic acid-4-β-glucoside effectively promoted cold acclimatization in mice via increased heat production and alleviation of oxidative stress in a cold environment. Thus, our work indicates that ferulic acid-4-β-glucoside is a potential therapeutic candidate for prevention and treatment of cold stress injury.