Does acclimation in distinct light conditions determine differences in the photosynthetic heat tolerance of coffee plants?

Worldwide coffee production is threatened by climate change, which highlights the importance of heat tolerance studies. Here we tested the hypothesis that photosynthetic heat tolerance in coffee varieties changes according to acclimation to distinct light conditions. Furthermore, we tested if heat tolerance is associated with the habitat of origin of the coffee species. We evaluated heat tolerance using chlorophyll fluorescence in varieties of Coffea arabica (Mundo Novo and Catuai Amarelo) and C. canephora (Conilon) grown in a common garden under two conditions: high (HS) and low (LS) sunlight. Leaf traits associated with leaf cooling were evaluated in plants grown in LS and HS and associations of heat tolerance with these traits were determined. The varieties tested had high photosynthetic heat tolerance, with temperatures above 54 °C leading to a 50% reduction in Fv /Fm (T50 ). The heat tolerance of each Coffea variety was unaffected by growth in distinct light conditions. Leaves of plants grown in LS were larger and had a lower fraction of the leaf area occupied by stomata (nast ). Heat tolerance was positively associated with leaf size and negatively with nast . C. canephora exhibited higher heat tolerance than C. arabica. The limited plasticity of heat tolerance in response to acclimation under distinct light conditions contradicts the prediction that plants acclimated to HS would have higher photosynthetic heat tolerance than those acclimated to LS. Our results on heat tolerance among Coffea species/varieties in HS and LS indicate the possibility of selection of varieties for better acclimation to ongoing climate changes.

ScAREB4 promotes potato constitutive and acclimated freezing tolerance associated with enhancing trehalose synthesis and oxidative stress tolerance.

Cold is a major environmental factor that restrains potato production. Abscisic acid (ABA) can enhance freezing tolerance in many plant species, but powerful evidence of the ABA-mediated signalling pathway related to freezing tolerance is still in deficiency. In the present study, cold acclimation capacity of the potato genotypes was enhanced alongside with improved endogenous content of ABA. Further exogenous application of ABA and its inhibitor (NDGA) could enhance and reduce potato freezing tolerance, respectively. Moreover, expression pattern of downstream genes in ABA signalling pathway was analysed and only ScAREB4 was identified with specifically upregulate in S. commersonii (CMM5) after cold and ABA treatments. Transgenic assay with overexpression of ScAREB4 showed that ScAREB4 promoted freezing tolerance. Global transcriptome profiling indicated that overexpression of ScAREB4 induced expression of TPS9 (trehalose-6-phosphate synthase) and GSTU8 (glutathione transferase), in accordance with improved TPS activity, trehalose content, higher GST activity and accumulated dramatically less H2 O2 in the ScAREB4 overexpressed transgenic lines. Taken together, the current results indicate that increased endogenous content of ABA is related to freezing tolerance in potato. Moreover, ScAREB4 functions as a downstream transcription factor of ABA signalling to promote cold tolerance, which is associated with increased trehalose content and antioxidant capacity.

"Living High-Training Low" for Olympic Medal Performance: What Have We Learned 25 Years After Implementation?

BACKGROUND: Altitude training is often regarded as an indispensable tool for the success of elite endurance athletes. Historically, altitude training emerged as a key strategy to prepare for the 1968 Olympics, held at 2300 m in Mexico City, and was limited to the "Live High-Train High" method for endurance athletes aiming for performance gains through improved oxygen transport. This "classical" intervention was modified in 1997 by the "Live High-Train Low" (LHTL) model wherein athletes supplemented acclimatization to chronic hypoxia with high-intensity training at low altitude. PURPOSE: This review discusses important considerations for successful implementation of LHTL camps in elite athletes based on experiences, both published and unpublished, of the authors. APPROACH: The originality of our approach is to discuss 10 key "lessons learned," since the seminal work by Levine and Stray-Gundersen was published in 1997, and focusing on (1) optimal dose, (2) individual responses, (3) iron status, (4) training-load monitoring, (5) wellness and well-being monitoring, (6) timing of the intervention, (7) use of natural versus simulated hypoxia, (8) robustness of adaptative mechanisms versus performance benefits, (9) application for a broad range of athletes, and (10) combination of methods. Successful LHTL strategies implemented by Team USA athletes for podium performance at Olympic Games and/or World Championships are presented. CONCLUSIONS: The evolution of the LHTL model represents an essential framework for sport science, in which field-driven questions about performance led to critical scientific investigation and subsequent practical implementation of a unique approach to altitude training.

Nutrition and Hydration for High-Altitude Alpinism: A Narrative Review.

This report aims to summarise the scientific knowledge around hydration, nutrition, and metabolism at high altitudes and to transfer it into the practical context of extreme altitude alpinism, which, as far as we know, has never been considered before in the literature. Maintaining energy balance during alpine expeditions is difficult for several reasons and requires a deep understanding of human physiology and the biological basis for altitude acclimation. However, in these harsh conditions it is difficult to reconcile our current scientific knowledge in sports nutrition or even for mountaineering to high-altitude alpinism: extreme hypoxia, cold, and the logistical difficulties intrinsic to these kinds of expeditions are not considered in the current literature. Requirements for the different stages of an expedition vary dramatically with increasing altitude, so recommendations must differentiate whether the alpinist is at base camp, at high-altitude camps, or attempting the summit. This paper highlights nutritional recommendations regarding prioritising carbohydrates as a source of energy and trying to maintain a protein balance with a practical contextualisation in the extreme altitude environment in the different stages of an alpine expedition. More research is needed regarding specific macro and micronutrient requirements as well as the adequacy of nutritional supplementations at high altitudes.

Post-exercise, passive heat acclimation with sauna or hot-water immersion provide comparable adaptations to performance in the heat in a military context.

To mitigate the effects of heat during operations in hot environments, military personnel will likely benefit from heat acclimation (HA) conducted prior to deployment. Using post-exercise, passive heating, 25 participants completed a 5 d HA regime in sauna (70 °C, 18% RH) or hot-water immersion (HWI) (40 °C) for ≤40 min, preceded and followed by a heat stress test (1-h walking at 5 km.h-1 in 33 °C, 77% RH in military uniform (20 kg) before an incremental ramp to exhaustion). Fifteen completed both regimes in a randomised, cross-over manner. While performance did not significantly improve (+14%, [-1, 29], p = .079), beneficial adaptations were observed for mean exercising core temperature (-0.2 °C, [-0.2, -0.2], p <.001), skin temperature (-0.2 °C, [-0.2, -0.2], p = 035) and heart rate (-8 bpm, [-6, -10], p<.001) in both conditions. Post-exercise, passive HA of either modality may benefit military units operating in the heat.Practitioner summary: Strategies are required to prevent health and performance impairments during military operations upon arrival in hot environments. Using a randomised, cross-over design, participants completed five-day passive, post-exercise heat acclimation using sauna or hot-water immersion. Both regimes elicited beneficial albeit modest heat adaptations.Abbreviations: HA: heat acclimation; HST: heat stress test; HWI: hot-water immersion; RH: relative humidity.

Dietary salt supplementation adversely affects thermal acclimation responses of flight ability in Drosophila melanogaster.

Cold acclimation may enhance low temperature flight ability, and salt loading can alter an insects' cold tolerance by affecting their ability to maintain ion balance in the cold. Presently however, it remains unclear if dietary salt impacts thermal acclimation of flight ability in insects. Here, we examined the effect of a combination of dietary salt loading (either NaCl or KCl) and low temperature exposure on the flight ability of Drosophila melanogaster at low (15 °C) and benign (optimal, 22 °C) temperatures. Additionally, we determined whether dietary salt supplementation translates into increased K+ and Na+ levels in the bodies of D. melanogaster. Lastly, we determined whether salt supplementation impacts body mass and wing morphology, to ascertain whether any changes in flight ability were potentially driven by flight-related morphometric variation. In control flies, we find that cold acclimation enhances low temperature flight ability over non-acclimated flies confirming the beneficial acclimation hypothesis. By contrast, flies supplemented with KCl that were cold acclimated and tested at a cold temperature had the lowest flight ability, suggesting that excess dietary KCl during development negates the beneficial cold acclimation process that would have otherwise taken place. Overall, the NaCl-supplemented flies and the control group had the greatest flight ability, whilst those fed a KCl-supplemented diet had the lowest. Dietary salt supplementation translated into increased Na+ and K+ concentration in the body tissues of flies, confirming that dietary shifts are reflected in changes in body composition and are not simply regulated out of the body by homeostasis over the course of development. Flies fed with a KCl-supplemented diet tended to be larger with larger wings, whilst those reared on the control or NaCl-supplemented diet were smaller with smaller wings. Additionally, the flies with greater flight ability tended to be smaller and have lower wing loading. In conclusion, dietary salts affected wing morphology as well as ion balance, and dietary KCl seemed to have a detrimental effect on cold acclimation responses of flight ability in D. melanogaster.

In-vitro propagation and phytochemical profiling of a highly medicinal and endemic plant species of the Himalayan region (Saussurea costus).

Efficient protocols for callus induction and micro propagation of Saussurea costus (Falc.) Lipsch were developed and phytochemical diversity of wild and in-vitro propagated material was investigated. Brown and red compact callus was formed with frequency of 80-95%, 78-90%, 70-95% and 65-80% from seeds, leaf, petiole and root explants, respectively. MS media supplemented with BAP (2.0 mgL-1), NAA (1.0 mgL-1) and GA3 (0.25 mgL-1) best suited for multiple shoot buds initiation (82%), while maximum shoot length was formed on media with BAP (1.5 mgL-1), NAA (0.25 mgL-1) and Kinetin (0.5 mgL-1). Full strength media with IAA (0.5 mgL-1) along with IBA (0.5 mgL-1) resulted in early roots initiation. Similarly, maximum rooting (87.57%) and lateral roots formation (up to 6.76) was recorded on full strength media supplemented with BAP (0.5 mgL-1), IAA (0.5 mgL-1) and IBA (0.5 mgL-1). Survival rate of acclimatized plantlets in autoclaved garden soil, farmyard soil, and sand (2:1:1) was 87%. Phytochemical analysis revealed variations in biochemical contents i.e. maximum sugar (808.32 µM/ml), proline (48.14 mg/g), ascorbic acid (373.801 mM/g) and phenolic compounds (642.72 mgL-1) were recorded from callus cultured on different stress media. Nonetheless, highest flavenoids (59.892 mg/g) and anthocyanin contents (32.39 mg/kg) were observed in in-vitro propagated plants. GC-MS analysis of the callus ethyl acetate extracts revealed 24 different phytochemicals. The variability in secondary metabolites of both wild and propagated plants/callus is reported for the first time for this species. This study may provide a baseline for the conservation and sustainable utilization of S. costus with implications for isolation of unique and pharmacologically active compounds from callus or regenerated plantlets.

Early transcriptional responses in Solanum peruvianum and Solanum lycopersicum account for different acclimation processes during water scarcity events.

Cultivated tomato Solanum lycopersicum (Slyc) is sensitive to water shortages, while its wild relative Solanum peruvianum L. (Sper), an herbaceous perennial small shrub, can grow under water scarcity and soil salinity environments. Plastic Sper modifies the plant architecture when suffering from drought, which is mediated by the replacement of leaf organs, among other changes. The early events that trigger acclimation and improve these morphological traits are unknown. In this study, a physiological and transcriptomic approach was used to understand the processes that differentiate the response in Slyc and Sper in the context of acclimation to stress and future consequences for plant architecture. In this regard, moderate (MD) and severe drought (SD) were imposed, mediating PEG treatments. The results showed a reduction in water and osmotic potential during stress, which correlated with the upregulation of sugar and proline metabolism-related genes. Additionally, the senescence-related genes FTSH6 protease and asparagine synthase were highly induced in both species. However, GO categories such as "protein ubiquitination" or "endopeptidase inhibitor activity" were differentially enriched in Sper and Slyc, respectively. Genes related to polyamine biosynthesis were induced, while several cyclins and kinetin were downregulated in Sper under drought treatments. Repression of photosynthesis-related genes was correlated with a higher reduction in the electron transport rate in Slyc than in Sper. Additionally, transcription factors from the ERF, WRKY and NAC families were commonly induced in Sper. Although some similar responses were induced in both species under drought stress, many important changes were detected to be differentially induced. This suggests that different pathways dictate the strategies to address the early response to drought and the consequent episodes in the acclimation process in both tomato species.

Isolation and Characterization of Cold-Adapted PGPB and Their Effect on Plant Growth Promotion.

Cold-adapted plant growth-promoting bacteria (PGPB) with multiple functions are an important resource for microbial fertilizers with low-temperature application. In this study, culturable cold-adapted PGPB strains with nitrogen fixation and phosphorus solubilization abilities were isolated. They were screened from root and rhizosphere of four dominant grass species in nondegraded alpine grasslands of the Qilian Mountains, China. Their other growth-promoting characteristics, including secretion of indole-3-acetic acid (IAA), production of siderophores and ACC deaminase, and antifungal activity, were further studied by qualitative and quantitative methods. In addition, whether the PGPB strains could still exert plant growth-promoting activity at 4°C was verified. The results showed that 67 isolates could maintain one or more growth-promoting traits at 4°C, and these isolates were defined as cold-adapted PGPB. They were divided into 8 genera by 16S rRNA gene sequencing and phylogenetic analysis, of which Pseudomonas (64.2%) and Serratia (13.4%) were the common dominant genera, and a few specific genera varied among the plant species. A test-tube culture showed that inoculation of Elymus nutans seedlings with cold-adapted PGPB possessing different functional characteristics had a significant growth-promoting effect under controlled low-temperature conditions, including the development of the roots and aboveground parts. Pearson correlation analysis revealed that different growth-promoting characteristics made different contributions to the development of the roots and aboveground parts. These cold-adapted PGPB can be used as excellent strain resources suitable for the near-natural restoration of degraded alpine grasslands or agriculture stock production in cold areas.

Acclimatization to diving: a systematic review.

Multiday hyperbaric exposure has been shown to reduce the incidence of decompression sickness (DCS) of compressed-air workers. This effect, termed acclimatization, has been addressed in a number of studies, but no comprehensive review has been published. This systematic review reports the findings of a literature search. PubMed, Ovid Embase, The Cochrane Library and Rubicon Research Repository were searched for studies reporting DCS incidence, venous gas embolism (VGE) or subjective health reports after multiday hyperbaric exposure in man and experimental animals. Twenty-nine studies fulfilled inclusion criteria. Three epidemiological studies reported statistically significant acclimatization to DCS in compressed-air workers after multiday hyperbaric exposure. One experimental study observed less itching after standardized simulated dives. Two human experimental studies reported lower DCS incidence after multiday immersed diving. Acclimatization to DCS has been observed in six animal species. Multiday diving had less consistent effect on VGE after hyperbaric exposure in man. Four studies observed acclimatization while no statistically significant acclimatization was reported in the remaining eight studies. A questionnaire study did not report any change in self-perceived health after multiday diving. This systematic review has not identified any study suggesting a sensitizing effect of multiday diving, and there is a lack of data supporting benefit of a day off diving after a certain number of consecutive diving days. The results suggest that multiday hyperbaric exposure probably will have an acclimatizing effect and protects from DCS. The mechanisms causing acclimatization, extent of protection and optimal procedure for acclimatization has been insufficiently investigated.

Three weeks of passive and intervallic heat at high temperatures (100±2 °C) in a sauna improve acclimation to external heat (42±2 °C) in untrained males.

Currently, the effect of passive heat acclimation on aerobic performance is still controversial. Therefore, this study aimed to observe the effect of passive and intervallic exposure to high temperatures (100 ± 2 °C) in untrained males. Forty healthy untrained men participated in this investigation. They were randomised into a Control Group (CG; n = 18) and an Experimental Group (EG; n = 22). Both groups performed maximum incremental tests until exhaustion in normothermia (GXT1; 22 ± 2 °C), and 48h afterwards, in hyperthermia (GXT2; 42 ± 2 °C). The EG performed 9 sessions of intervallic exposure to heat (100 ± 2 °C) over 3 weeks. Subsequently, both groups performed two maximal incremental trials in normothermia (GXT3; 22 ± 2 °C) and 48h later, in hyperthermia (GXT4; 42 ± 2 °C). In each test, the maximal ergospirometric parameters and the aerobic (VT1), anaerobic (VT2) and recovery ventilatory thresholds were recorded. The Wilcoxon Test was used for intra-group comparisons and the Mann-Whitney U for inter-group comparisons. There were improvements in absolute VO2max (p = 0.049), W (p = 0.005) and O2pulse (p = 0.006) in hyperthermia. In VT1 there was an increase in W (p = 0.046), in VO2 in absolute (p = 0.025) and relative (p = 0.013) values, O2pulse (p = 0.006) and VE (p = 0.028) in hyperthermia. While W increased in hyperthermia (p = 0.022) at VT2. The results suggest that passive and intervallic acclimation at high temperatures improves performance in hyperthermia. This protocol could be implemented in athletes when they have to compete in hot environments.

Impact of passive heat acclimation on markers of kidney function during heat stress.

NEW FINDINGS: What is the central question of this study? Does passive heat acclimation alter glomerular filtration rate and urine-concentrating ability in response to passive heat stress? What is the main finding and its importance? Glomerular filtration rate remained unchanged after passive heat stress, and heat acclimation did not alter this response. However, heat acclimation mitigated the reduction in urine-concentrating ability and reduced the incidence of albuminuria in young healthy adults after passive heat stress. Collectively, these results suggest that passive heat acclimation might improve structural integrity and reduce glomerular permeability during passive heat stress. ABSTRACT: Little is known about the effect of heat acclimation on kidney function during heat stress. The purpose of this study was to determine the impact of passive heat stress and subsequent passive heat acclimation on markers of kidney function. Twelve healthy adults (seven men and five women; 26 ± 5 years of age; 72.7 ± 8.6 kg; 172.4 ± 7.5 cm) underwent passive heat stress before and after a 7 day controlled hyperthermia heat acclimation protocol. The impact of passive heat exposure on urine and serum markers of kidney function was evaluated before and after heat acclimation. Glomerular filtration rate, determined from creatinine clearance, was unchanged with passive heat stress before (pre, 133 ± 41 ml min-1 ; post, 127 ± 51 ml min-1 ; P = 0.99) and after (pre, 129 ± 46 ml min-1 ; post, 130 ± 36 ml min-1 ; P = 0.99) heat acclimation. The urine-to-serum osmolality ratio was reduced after passive heating (P < 0.01), but heat acclimation did not alter this response. In comparison to baseline, free water clearance was greater after passive heating before (pre, -0.86 ± 0.67 ml min-1 ; post, 0.40 ± 1.01 ml min-1 ; P < 0.01) but not after (pre, -0.16 ± 0.57 ml min-1 ; post, 0.76 ± 1.2 ml min-1 ; P = 0.11) heat acclimation. Furthermore, passive heating increased the fractional excretion rate of potassium (P < 0.03) but not sodium (P = 0.13) or chloride (P = 0.20). Lastly, heat acclimation reduced the fractional incidence of albuminuria after passive heating (before, 58 ± 51%; after, 8 ± 29%; P = 0.03). Collectively, these results demonstrate that passive heat stress does not alter the glomerular filtration rate. However, heat acclimation might improve urine-concentrating ability and filtration within the glomerulus.

Acclimation potential of Noni (Morinda citrifolia L.) plant to temperature stress is mediated through photosynthetic electron transport rate.

Noni (Morindacitrifolia L.), a tropical, medicinal plant of the family Rubiaceae utilized since 2000 y ago by the Polynesians, is currently facing a major challenge in production vis-a-vis climate change. The worldwide average temperatures continue to fluctuate, resulting in extremely cold winters and hot summers that reduce plant productivity. Photosynthetic apparatus is an exceptionally sensitive component to estimate the degree of damage at contrasting temperatures. The present study was aimed to evaluate the temperature stress response of Noni plant using the chlorophyll a fluorescence OJIP transients (OJIP transients). Results showed the declined photosynthetic pigment pool and reduced functional and structural integrity of the photosynthetic apparatus under very low- and high-temperature treatments. Drastically lower yield parameters such as φ(Po) and φ(Eo), efficiency ψ(Eo) and performance indices - PIabs and PItotal, and accumulation of inactive reaction centers were observed. Consecutively, a lower level of calculated electron transport from PSII to PSI was observed. In contrast, the enhanced δRo indicates that PSI is more thermo-tolerant as compared to PSII. Additionally, very low and high temperatures cause an increase in antenna size (ABS/RC) and the decrease in the amplitude of I to P phase of fluorescence transient. Overall, the photosynthetic apparatus of leaf tissue was more sensitive to low and high temperatures than the developing fruit. The findings of the present study demonstrated the potential role of thylakoid components of the photosynthetic apparatus, which might be crucial in regulating the temperature stress response in the Noni plant, and thereby crop improvement.

Intermittent post-exercise sauna bathing improves markers of exercise capacity in hot and temperate conditions in trained middle-distance runners.

PURPOSE: This study investigated whether intermittent post-exercise sauna bathing across three-weeks endurance training improves exercise heat tolerance and exercise performance markers in temperate conditions, compared to endurance training alone. The subsidiary aim was to determine whether exercise-heat tolerance would further improve following 7-Weeks post-exercise sauna bathing. METHODS: Twenty middle-distance runners (13 female; mean ± SD, age 20 ± 2 years, [Formula: see text]O2max 56.1 ± 8.7 ml kg-1 min-1) performed a running heat tolerance test (30-min, 9 km h-1/2% gradient, 40 °C/40%RH; HTT) and temperate (18 °C) exercise tests (maximal aerobic capacity [[Formula: see text]O2max], speed at 4 mmol L-1 blood lactate concentration ([La-]) before (Pre) and following three-weeks (3-Weeks) normal training (CON; n = 8) or normal training with 28 ± 2 min post-exercise sauna bathing (101-108 °C, 5-10%RH) 3 ± 1 times per week (SAUNA; n = 12). Changes from Pre to 3-Weeks were compared between-groups using an analysis of co-variance. Six SAUNA participants continued the intervention for 7 weeks, completing an additional HTT (7-Weeks; data compared using a one-way repeated-measures analysis of variance). RESULTS: During the HTT, SAUNA reduced peak rectal temperature (Trec; - 0.2 °C), skin temperature (- 0.8 °C), and heart rate (- 11 beats min-1) more than CON at 3-Weeks compared to Pre (all p < 0.05). SAUNA also improved [Formula: see text]O2max (+ 0.27 L-1 min-1; p = 0.02) and speed at 4 mmol L-1 [La-] (+ 0.6 km h-1; p = 0.01) more than CON at 3-Weeks compared to Pre. Only peak Trec (- 0.1 °C; p = 0.03 decreased further from 3-Weeks to 7-Weeks in SAUNA (other physiological variables p > 0.05). CONCLUSIONS: Three-weeks post-exercise sauna bathing is an effective and pragmatic method of heat acclimation, and an effective ergogenic aid. Extending the intervention to seven weeks only marginally improved Trec.

Effects of short-term heat acclimation on whole-body heat exchange and local nitric oxide synthase- and cyclooxygenase-dependent heat loss responses in exercising older men.

NEW FINDINGS: What is the central question of this study? Does short-term heat acclimation enhance whole-body evaporative heat loss and augment nitric oxide synthase (NOS)-dependent cutaneous vasodilatation and NOS- and cyclooxygenase (COX)-dependent sweating, in exercising older men? What is the main finding and its importance? Our preliminary data (n = 8) demonstrated that short-term heat acclimation improved whole-body evaporative heat loss, but it did not influence the effects of NOS and/or COX inhibition on cutaneous vasodilatation or sweating in older men during an exercise-heat stress. These outcomes might imply that although short-term heat acclimation enhances heat dissipation in older men, it does not modulate NOS- and COX-dependent control of cutaneous vasodilatation or sweating on the forearm. ABSTRACT: Ageing is associated with decrements in whole-body heat loss (evaporative + dry heat exchange), which might stem from alterations in nitric oxide synthase (NOS)- and cyclooxygenase (COX)-dependent cutaneous vasodilatation and sweating. We evaluated whether short-term heat acclimation would (i) enhance whole-body heat loss primarily by increasing evaporative heat loss, and (ii) augment NOS-dependent cutaneous vasodilatation and NOS- and COX-dependent sweating, in exercising older men. Eight older men [mean (SD) age, 59 (8) years] completed a calorimetry and microdialysis trial before and after 7 days of exercise-heat acclimation. For the calorimetry trials, whole-body evaporative and dry heat exchange were assessed using direct calorimetry during 30 min bouts of cycling at light, moderate and vigorous metabolic heat productions (150, 200 and 250 W/m2 , respectively) in dry heat (40°C, 20% relative humidity). For the microdialysis trials, local cutaneous vascular conductance and sweat rate were assessed during 60 min exercise in the heat (35°C, 20% relative humidity) at four dorsal forearm skin sites treated with lactated Ringer solution (control), NOS inhibitor, COX inhibitor or combined NOS and COX inhibitors, via microdialysis. Evaporative heat loss during moderate (P = 0.036) and vigorous (P = 0.021) exercise increased after acclimation. Inhibition of NOS alone reduced cutaneous vascular conductance to a similar extent before and after acclimation (P < 0.040), whereas separate and combined NOS and COX inhibition had no significant effects on sweating relative to the control site (P = 0.745). Our preliminary results might suggest that short-term heat acclimation improves evaporative heat loss, but does not significantly modulate the contributions of NOS or COX to cutaneous vasodilatation or sweating on the forearm in older men during an exercise-heat stress.

Revealing mitogenome-wide DNA methylation and RNA editing of three Ascomycotina fungi using SMRT sequencing.

Beauveria bassiana, Cordyceps militaris and Ophiocordyceps sinensis (Ascomycotina) are traditional Chinese medicines. Here, mitogenomes of these three Ascomycotina fungi were sequenced and de-novo assembled using single-molecule real-time sequencing. The results showed that their complete mitogenomes were 31,258, 31,854 and 157,584 bp, respectively, with sequencing depth approximately 278,760×, 326,283× and 69,385×. Types of repeat sequences were mainly (AA)n, (AAT)n, (TA)n and (TATT)n. DNA methylation motifs were revealed in DNA modifications of these three fungi. We discovered new models of RNA editing through analysis of transcriptomes from B. bassiana and C. militaris. These data lay a solid foundation for further genetic and biological studies about these three fungi, especially for elucidating the mitogenome evolution and exploring the regulatory mechanism of adapting environment.

Iron insufficiency diminishes the erythropoietic response to moderate altitude exposure.

The effects of iron stores and supplementation on erythropoietic responses to moderate altitude in endurance athletes were examined. In a retrospective study, red cell compartment volume (RCV) responses to 4 wk at 2,500 m were assessed in athletes with low (n = 9, ≤20 and ≤30 ng/mL for women and men, respectively) and normal (n = 10) serum ferritin levels ([Ferritin]) without iron supplementation. In a subsequent prospective study, the same responses were assessed in athletes (n = 26) with a protocol designed to provide sufficient iron before and during identical altitude exposure. The responses to a 4-wk training camp at sea level were assessed in another group of athletes (n = 13) as controls. RCV and maximal oxygen uptake (V̇o2max) were determined at sea level before and after intervention. In the retrospective study, athletes with low [Ferritin] did not increase RCV (27.0 ± 2.9 to 27.5 ± 3.8 mL/kg, mean ± SD, P = 0.65) or V̇o2max (60.2 ± 7.2 to 62.2 ± 7.5 mL·kg-1·min-1, P = 0.23) after 4 wk at altitude, whereas athletes with normal [Ferritin] increased both (RCV: 27.3 ± 3.1 to 29.8 ± 2.4 mL/kg, P = 0.002; V̇o2max: 62.0 ± 3.1 to 66.2 ± 3.7 mL·kg-1·min-1, P = 0.003). In the prospective study, iron supplementation normalized low [Ferritin] observed in athletes exposed to altitude (n = 14) and sea level (n = 6) before the altitude/sea-level camp and maintained [Ferritin] within normal range in all athletes during the camp. RCV and V̇o2max increased in the altitude group but remained unchanged in the sea-level group. Finally, the increase in RCV correlated with the increase in V̇o2max [(r = 0.368, 95% confidence interval (CI): 0.059-0.612, P = 0.022]. Thus, iron deficiency in athletes restrains erythropoiesis to altitude exposure and may preclude improvement in sea-level athletic performance.NEW & NOTEWORTHY Hypoxic exposure increases iron requirements and utilization for erythropoiesis in athletes. This study clearly demonstrates that iron deficiency in athletes inhibits accelerated erythropoiesis to a sojourn to moderate high altitude and may preclude a potential improvement in sea-level athletic performance with altitude training. Iron replacement therapy before and during altitude exposure is important to maximize performance gains after altitude training in endurance athletes.

Genome sequencing and transcriptome analyses of the Siberian hamster hypothalamus identify mechanisms for seasonal energy balance.

Synthesis of triiodothyronine (T3) in the hypothalamus induces marked seasonal neuromorphology changes across taxa. How species-specific responses to T3 signaling in the CNS drive annual changes in body weight and energy balance remains uncharacterized. These experiments sequenced and annotated the Siberian hamster (Phodopus sungorus) genome, a model organism for seasonal physiology research, to facilitate the dissection of T3-dependent molecular mechanisms that govern predictable, robust, and long-term changes in body weight. Examination of the Phodopus genome, in combination with transcriptome sequencing of the hamster diencephalon under winter and summer conditions, and in vivo-targeted expression analyses confirmed that proopiomelanocortin (pomc) is a primary genomic target for the long-term T3-dependent regulation of body weight. Further in silico analyses of pomc promoter sequences revealed that thyroid hormone receptor 1ß-binding motif insertions have evolved in several genera of the Cricetidae family of rodents. Finally, experimental manipulation of food availability confirmed that hypothalamic pomc mRNA expression is dependent on longer-term photoperiod cues and is unresponsive to acute, short-term food availability. These observations suggest that species-specific responses to hypothalamic T3, driven in part by the receptor-binding motif insertions in some cricetid genomes, contribute critically to the long-term regulation of energy balance and the underlying physiological and behavioral adaptations associated with the seasonal organization of behavior.

Development of a process for microbial sulfate reduction in cold mining waters - Cold acclimation of bacterial consortia from an Arctic mining district.

Biological sulfate removal is challenging in cold climates due to the slower metabolism of mesophilic bacteria; however, cold conditions also offer the possibility to isolate bacteria that have adapted to low temperatures. The present research focused on the cold acclimation and characterization of sulfate-reducing bacterial (SRB) consortia enriched from an Arctic sediment sample from northern Finland. Based on 16S rDNA analysis, the most common sulfate-reducing bacterium in all enriched consortia was Desulfobulbus, which belongs to the δ-Proteobacteria. The majority of the cultivated consortia were able to reduce sulfate at temperatures as low as 6 °C with succinic acid as a carbon source. The sulfate reduction rates at 6 °C varied from 13 to 42 mg/L/d. The cultivation medium used in this research was a Postgate medium supplemented with lactate, ethanol or succinic acid. The obtained consortia were able to grow with lactate and succinic acid but surprisingly not with ethanol. Enriched SRB consortia are useful for the biological treatment of sulfate-containing industrial wastewaters in cold conditions.

Piriformospora indica promotes the growth of the in-vitro-raised Cymbidium aloifolium plantlet and their acclimatization.

Cymbidium aloifolium is known for its ornamental and medicinal values. It has been listed as threatened orchid species. In this study, in vitro propagated C. aloifolium plantlets were interacted with the Piriformospora indica. The growth assay was performed for 45 days; the plant growth pattern such as number and length of roots and shoots were measured. Microscopic study of the root section stained by trypan blue was done to detect the peloton formation. The methanol extracts of the fungal colonized plant as well as uncolonized (control) plant were prepared and various metabolites were identified by gas chromatography mass spectroscopy. Acclimatization was done in a substrate composition of coco peat: gravel: charcoal in ratio 2:2:1. P. indica-colonized plantlet showed the highest growth with the formation of clamdospore in the root section. The growth regulator such as auxin, ascorbic acid, andrographolide, hexadecanoic acid, and DL-proline were identified. After three months of field transfer, plantlet colonized by P. indica survived and remained healthy as compared to uncolonized control plantlet.