Development and validation of a behavioral acclimation protocol for cats to respiration chambers used for indirect calorimetry studies

Cats exposed to novel environments initiate stress responses by behavioral and physiological changes that modify metabolism and lead to the collection of unreliable data. Fourteen cats (10 ± 2 months) were subjected to an 11-week acclimation procedure to adapt to restriction within chambers used for indirect calorimetry studies. Cats were acclimated to chambers in their home environments, to chambers in the study room, and to increasing periods of restriction within chambers. Ten additional cats (11 ± 1 month), used as controls, were subjected to a single 5-hr restriction without any prior exposure. Stress level, feed intake, fearfulness, and eliminations were recorded. Latencies to approach a novel object peaked on Weeks 4 and 8 (p < .05). Cat-Stress-Scores (CSS) declined with exposure and on Week 11, stress levels were low and consistent (p < .05). CSS was greater in unacclimated versus acclimated cats (p < .05). In conclusion, acclimation protocols prepare cats for repeated, temporary restriction within chambers, whereas short acclimations do not. A step-up acclimation procedure with behavioral indices of stress should be utilized to prepare cats for research that necessitates restriction.     

Evaluation of sodium bisulphate and phosphoric acid as uine acidifiers for cats

Eighteen cats were used to compare the urine acidifying properties of sodium bisulphate to phosphoric acid. Acidifying agents were added at one of three concentrations (0.4, 0.6, or 0.8%, as-is basis). Cats were offered a commercial diet to determine basal urinary pH, and then again for a 1 week period between blocks 1 and 2. Cats were acclimated to the diets for 6 days, and urine samples were collected on day 7 at 0, 4, and 8 h post-feeding to obtain pre- and postprandial urinary pH. Intakes of diets containing sodium bisulphate tended (P < 0.07) to be lower than intakes of diets containing phosphoric acid. Cats consuming the 0.8% phosphoric acid diet had higher (P < 0.05) food intakes than cats consuming either the 0.4 or 0.6% phosphoric acid-containing diets. There was significant (P = 0.01) linear and quadratic response for food intake in cats consuming the sodium bisulphate-containing diet. Cats consuming the 0.4 and 0.8% phosphoric acid-containing diets tended (P = 0.07) to have higher water intakes than cats consuming the 0.6% phosphoric acid-containing diet. There were no differences (P > 0.05) in urine pH and specific gravity between cats fed the different acidifier types. Cats consuming the 0.6% phosphoric acid-containing diet tended (P = 0.07) to have a higher urine pH 8 h post-feeding than cats consuming the 0.4 and 0.8% phosphoric acid-containing diets. Urine pH was highest at 4 h post-feeding except for cats fed the 0.4% sodium bisulphate- and the 0.6% phosphoric acid-containing diets. No differences (P > 0.05) between acidifiers were found in faecal score or in faecal dry matter and organic matter concentrations. A quadratic response was detected in faecal score for cats consuming the phosphoric acid-containing diets. Cats consuming the 0.6% phosphoric acid diet tended (P = 0.06) to have a lower faecal score than cats consuming the 0.4 and 0.8% phosphoric acid diets. For faecal dry matter, a linear trend was detected in cats consuming the sodium bisulphate (P = 0.08) and phosphoric acid-containing (P = 0.04) diets. Sodium bisulphate and phosphoric acid generally behaved in a similar fashion when incorporated in dry cat diets.     

Maternal-Neonatal Pheromone/Interomone Added to Cat Litter Improves Litter Box Use and Reduces Aggression in Pair-Housed Cats

Introducing a new cat into a household with one or more resident cats can be a significant source of stress for the cats involved. These studies sought to determine if rabbit maternal-neonatal pheromone (2-methyl-2-butenal [2M2B]) in litter impacted cat social behaviors and litter box use. Study 1 determined that cats preferred to eliminate in litter containing 2M2B; other semiochemicals tested did not change litter box use. Cats prone to aggression were identified in an intermediate pilot study, and eight pairs of these cats were selected for Study 2. In Study 2, cat pairs were provided litter containing either vehicle or 2M2B for 24 hours. Cats experiencing control litter displayed more aggression during the first 6 hours (p < .01) and spent more time using the litter box 12 hours and 18 hours after pairing compared with cats experiencing litter with 2M2B (p = .02). These results suggest 2M2B-infused cat litter may act as an interomone in cats housed domestically to prevent initial occurrences of aggression and may improve cat welfare in multicat households.     

The Legal Status of Cats in New Zealand: A Perspective on the Welfare of Companion,Stray, and Feral Domestic Cats (Felis catus)

Pinpointing and safeguarding the welfare status of domestic cats is problematic, especially in New Zealand where cats are introduced predators with significant impact on indigenous fauna. Usually the identification of welfare status depends on conservational, legal, and public attitudes that are often contrasting. Cats may rapidly transgress definitions placed on them, confounding attempts to categorize them. In 1 generation, cats can move from a human-dependent state (“stray” or “companion”) to wild (“feral”). Often this categorization uses arbitrary behavioral and or situational parameters; consequent treatment and welfare protection for these cats are similarly affected. Terminology used to describe cats is not equitable across research. However, the New Zealand Animal Welfare (Companion Cats) Code of Welfare 2007 seeks to create a new definition of the terms companion, stray, and feral. It distinguishes between cats who live within and without human social constructs. This legislation mandates that cats in human environments or indirectly dependent on humans cannot be classified as feral. Such definitions may prove vital when safeguarding the welfare of free-living domestic cats and cat colonies.     

Reasons for Relinquishment and Return of Domestic Cats (Felis Silvestris Catus) to Rescue Shelters in the UK

ABSTRACT

Significant numbers of cats enter rescue and re-homing facilities each year, over half of which are relinquished directly by owners. Identifying the reasons why owners decide to give up their pet is an important step in the development of education strategies to encourage retention of cats by their owners. In addition, identifying why adopting owners fail to retain their new cats is important in the refinement of homing policies. Characteristics of 6,089 cats relinquished and returned to 11 rescue facilities in the UK were recorded over a year. In addition, information was collected on the reason why owners gave up, or brought back, their pet. Sixty percent of cats and kittens entering shelters were relinquished by owners, with 19% being due to owner circumstances, such as moving to rented accommodation or changes in family circumstances. Seven percent were for behavioral reasons, and 5% because of the occurrence of allergy or asthma in owners. Returned cats were significantly more likely to be older (Mann Whitney U, Z = –9.167, p < 0.001) and neutered (Pearson χ² = 110.0, df = 2, p < 0.001) than the general relinquished population. The reasons for original relinquishment and return of owned cats were also significantly different (Pearson χ² = 84.4, df = 6, p < 0.001), with 38% of cats being returned for behavioral reasons, and 18% because of allergy or asthma. The commonest behavioral reason for both relinquishment and return was aggression between cats in the household.     

Thermal maxima for juvenile shortnose sturgeon acclimated to different temperatures

Many populations of shortnose sturgeon, Acipenser brevirostrum, in the southeastern United States continue to suffer from poor juvenile recruitment. High summer water temperatures, which may be exacerbated by anthropogenic activities, are thought to affect recruitment by limiting available summer habitat. However, information regarding temperature thresholds of shortnose sturgeon is limited. In this study, the thermal maximum method and a heating rate of 0.1°C min⁻¹ was used to determine critical and lethal thermal maxima for young-of-the-year (YOY) shortnose sturgeon acclimated to temperatures of 19.5 and 24.1°C. Fish used in the experiment were 0.6 to 35.0 g in weight and 64 to 140 days post hatch (dph) in age. Critical thermal maxima were 33.7°C (±0.3) and 35.1°C (±0.2) for fish acclimated to 19.5 and 24.1°C, respectively. Critical thermal maxima significantly increased with an increase in acclimation temperature (p < 0.0001). Lethal thermal maxima were 34.8°C (±0.1) and 36.1°C (±0.1) for fish acclimated to 19.5 and 24.1°C, respectively. Lethal thermal maxima were significantly affected by acclimation temperature, the log₁₀ (fish weight), and the interaction between log₁₀(fish weight) and acclimation temperature (p < 0.0001). Thermal maxima were used to estimate upper limits of safe temperature, thermal preferences, and optimal growth temperatures of YOY shortnose sturgeon. Upper limits of safe temperature were similar to previous temperature tolerance information and indicate that summer temperatures in southeastern rivers may be lethal to YOY shortnose sturgeon if suitable thermal refuge cannot be found.     

Plastic and evolutionary responses to heat stress in a temperate dung fly: negative correlation between basal and induced heat tolerance?

Extreme weather events such as heat waves are becoming more frequent and intense. Populations can cope with elevated heat stress by evolving higher basal heat tolerance (evolutionary response) and/or stronger induced heat tolerance (plastic response). However, there is ongoing debate about whether basal and induced heat tolerance are negatively correlated and whether adaptive potential in heat tolerance is sufficient under ongoing climate warming. To evaluate the evolutionary potential of basal and induced heat tolerance, we performed experimental evolution on a temperate source population of the dung fly Sepsis punctum. Offspring of flies adapted to three thermal selection regimes (Hot, Cold and Reference) were subjected to acute heat stress after having been exposed to either a hot‐acclimation or non‐acclimation pretreatment. As different traits may respond differently to temperature stress, several physiological and life history traits were assessed. Condition dependence of the response was evaluated by exposing juveniles to different levels of developmental (food restriction/rearing density) stress. Heat knockdown times were highest, whereas acclimation effects were lowest in the Hot selection regime, indicating a negative association between basal and induced heat tolerance. However, survival, adult longevity, fecundity and fertility did not show such a pattern. Acclimation had positive effects in heat‐shocked flies, but in the absence of heat stress hot‐acclimated flies had reduced life spans relative to non‐acclimated ones, thereby revealing a potential cost of acclimation. Moreover, body size positively affected heat tolerance and unstressed individuals were less prone to heat stress than stressed flies, offering support for energetic costs associated with heat tolerance. Overall, our results indicate that heat tolerance of temperate insects can evolve under rising temperatures, but this response could be limited by a negative relationship between basal and induced thermotolerance, and may involve some but not other fitness‐related traits.     

Behavioural salinity preferences of juvenile green sturgeon Acipenser medirostris acclimated to fresh water and full‐strength salt water

To quantify the salinity preference of juvenile green sturgeon Acipenser medirostris, two groups of A. medirostris [140 days post hatch (dph); total length (L_T) 38·0–52·5 cm] were acclimated to either near fresh water (mean ± s.e . salinity = 3·2 ± 0·6) or full‐strength salt water (34·1 ± 1·2) over 8 weeks. Following acclimation, the two groups were divided into experimental and control groups, where experimental A. medirostris from both freshwater and saltwater acclimations were individually introduced (200–220 dph) into a rectangular salinity‐preference flume (maximum salinity gradient: 5–33). Control A. medirostris were presented with only their acclimation water (fresh water or salt water) on both sides of the flume. It was demonstrated that A. medirostris acclimated to both salt water and fresh water spent a significantly greater amount of time on the side of the testing area with the highest salinity concentration (P < 0·05 and P < 0·001, respectively) while control A. medirostris spent an equal amount of time on each side of the flume. These findings indicate that juvenile A. medirostris are not only capable of detecting salt water within the first year of their lives but perhaps are actively seeking out saline environments as they move through a watershed. Establishing A. medirostris salinity preferences provides a better understanding of the early life history of this threatened species, shedding light on possible outmigration timing.     

EVOLUTIONARY ADAPTATION TO TEMPERATURE. VI. PHENOTYPIC ACCLIMATION AND ITS EVOLUTION IN ESCHERICHIA COLI

Acclimation refers to reversible, nongenetic changes in phenotype that are induced by specific environmental conditions. Acclimation is generally assumed to improve function in the environment that induces it (the beneficial acclimation hypothesis). In this study, we experimentally tested this assumption by measuring relative fitness of the bacterium Escherichia coli acclimated to different thermal environments. The beneficial acclimation hypothesis predicts that bacteria acclimated to the temperature of competition should have greater fitness than do bacteria acclimated to any other temperature. The benefit predicted by the hypothesis was found in only seven of 12 comparisons; in the other comparisons, either no statistically demonstrable benefit was observed or a detrimental effect of acclimation was demonstrated. For example, in a lineage evolutionarily adapted to 37°C, bacteria acclimated to 37°C have a higher fitness at 32°C than do bacteria acclimated to 32°C, a result exactly contrary to prediction; acclimation to 27°C or 40°C prior to competition at those temperatures confers no benefit over 37°C acclimated forms. Consequently, the beneficial acclimation hypothesis must be rejected as a general prediction of the inevitable result of phenotypic adjustments associated with new environments. However, the hypothesis is supported in many instances when the acclimation and competition temperatures coincide with the historical temperature at which the bacterial populations have evolved. For example, when the evolutionary temperature of the population was 37°C, bacteria acclimated to 37°C had superior fitness at 37°C to those acclimated to 32°C; similarly, bacteria evolutionarily adapted to 32°C had a higher fitness during competition at 32°C than they did when acclimated to 37°C. The more surprising results are that when the bacteria are acclimated to their historical evolutionary temperature, they are frequently competitively superior even at other temperatures. For example, bacteria that have evolved at either 20°C or 32°C and are acclimated to their respective evolutionary temperatures have a greater fitness at 37°C than when they are acclimated to 37°C. Thus, acclimation to evolutionary temperature may, as a correlated consequence, enhance performance not only in the evolutionary environment, but also in a variety of other thermal environments.     

Temperature acclimation alters cardiac performance in the lobster Homarus americanus

The American lobster is a poikilotherm that inhabits a marine environment where temperature varies over a 25°C range and depends on the winds, the tides and the seasons. To determine how cardiac performance depends on the water temperature to which the lobsters are acclimated we measured lobster heart rates in vivo. The upper limit for cardiac function in lobsters acclimated to 20°C is approximately 29°C, 5°C warmer than that measured in lobsters acclimated to 4°C. Warm acclimation also slows the lobster heart rate within the temperature range from 4 to 12°C. Both effects are apparent after relatively short periods of warm acclimation (3–14 days). However, warm acclimation impairs cardiac function at cold temperatures: following several hours exposure to frigid (<5°C) temperatures heart rates become slow and arrhythmic in warm acclimated, but not cold acclimated, lobsters. Thus, acclimation temperature determines the thermal limits for cardiac function at both extremes of the 25°C temperature range lobsters inhabit in the wild. These observations suggest that regulation of cardiac thermal tolerance by the prevailing environmental temperature protects against the possibility of cardiac failure due to thermal stress.     

Behavior and Welfare of Domestic Cats Housed in Cages Larger than U.S. Norm

The effect of providing additional floor space on cat behavior and welfare is not well documented. This study involved replication of an investigation of cats’ responses to enhanced cage and room environments using cages of 0.56 m² with the same methodology but an increased space allowance of 1.1 m². Singly housed adult cats (n = 59) were randomly assigned to a treatment group that was a combination of a managed or unmanaged room and an enriched or unenriched cage environment. Cats were observed for 2 days for maintenance, affiliative, and avoidant behaviors using scan sampling and 5-min, continuous focal sampling. At the end of Day 2, cats’ reactions to the approach of an unfamiliar person were assessed. Cats housed in enriched/managed environments exhibited more maintenance and affiliative behaviors and fewer avoidant behaviors than cats in unmanaged/unenriched environments, suggesting that macro and micro environments may be equally relevant to the cat. Increased space did not enhance the cats’ welfare outcomes, suggesting that the provision of additional cage space may not be as important to the cat as a managed housing environment.     

Characteristics of Cats Admitted to Czech Shelters

The aim of this study was to describe the numbers and characteristics of cats entering Czech shelters. Records of sheltered cats were collected from three cat shelters situated in different regions of the Czech Republic from 2011 to 2015. A total of 2170 cat admissions were analyzed in this study. Significantly (p < .001) greater numbers of females (56%) were admitted. Most cats (60%) were admitted when they were aged younger than six months. Cats with dark coat colors prevailed (73%), cats with medium-shade colors followed (20%), and light-colored cats were the rarest (7%). The greatest numbers of cats were admitted in summer (36%), followed by autumn (33%). The fewest cats were admitted in winter (14%). Adoption was the most common outcome for admitted cats (65%), followed by unassisted death (22%) and euthanasia (11%) due to health reasons. Only 2% of cats were reclaimed from the shelters by their original caretakers. The length of stay ranged from 0 days to 1736 days with a median of 45 days. These findings may help shelter operators define optimal strategies and operational plans.     

Expression of dehydration-stress-related genes in the crowns of wheatgrass species [Lophopyrum elongatum (Host) A. Love and Agropyron desertorum (Fisch. ex Link.) Schult.] having contrasting acclimation to salt, cold and drought

Agropyron desertorum and Lophopyrum elongatum were grown in a control environment or acclimated in high‐salt (daily exposure to 75 or 150 m M NaCl for 6 d), cold (6/2 °C for 14 d) or drought environments (watering withheld for 6 d). Lophopyrum elongatum was constitutively tolerant to salt and also acclimated more to salt than did A. desertorum whereas A. desertorum acclimated more to cold and drought. Dehydrin and non‐specific lipid transfer protein (nsLTP) mRNA sequences and polypeptides increased more, during acclimation to cold and drought, in A. desertorum than in L. elongatum crowns. Expression of immunologically identified dehydrin polypeptides was much higher in drought‐acclimated A. desertorum than in any other species/treatment combination. The most strongly expressed were 42 and 20 kDa. No change in dehydrin or nsLTP polypeptides were detected in the crowns during acclimation to salt. Overall, there was stronger acclimation to dehydrative stresses, at the molecular level, in A. desertorum than in L. elongatum crowns. Differences in dehydrin and nsLTP mRNA and polypeptide expression during acclimation to different stresses indicated that plants sense the differences between different primary potential causes of cellular dehydration.     

低温驯化后水椰八角铁甲生理活性物质含量的变化

【目的】分析低温驯化后水椰八角铁甲Octodonta nipae体内各种生理活性物质含量的变化,为揭示水椰八角铁甲耐寒机制提供理论基础。【方法】以25℃处理为对照,将水椰八角铁甲各虫态于12.5, 15, 17.5和20℃驯化处理10 d后,比较其体内的游离水、蛋白质、氨基酸、粗脂肪、甘油和可溶性糖原等生理活性物质含量的变化。【结果】低温驯化显著影响铁甲体内上述物质的含量水平。低温驯化能提高该铁甲体内甘油和游离氨基酸的含量,降低游离水、蛋白质、粗脂肪、可溶性糖原的含量。与对照相比,12.5℃驯化对该铁甲各虫态体内游离水含量存在显著影响(P<0.01);经12.5, 15, 17.5和20.0℃驯化后,该铁甲各虫态体内蛋白质、粗脂肪含量与对照相比均存在显著差异(P<0.01);经125,150和175℃驯化后,该铁甲各虫态体内游离氨基酸含量与对照存在显著差异(P<0.01);经12.5,15.0,17.5和20℃驯化后,该铁甲各虫态（2龄幼虫除外）体内甘油含量与对照相比存在显著差异(P<0.01);12.5, 15.0, 17.5和20℃驯化对除2龄幼虫、蛹和成虫外的铁甲其他各虫态体内可溶性糖原含量存在显著影响。经15.0℃驯化处理后铁甲各虫态体内平均甘油含量最高,比对照25℃的平均甘油含量高出约9.4倍,而经12.5℃驯化处理的虫体内的平均甘油含量仅增加3.5倍。【结论】低温驯化对水椰八角铁甲体内相关生理活性物质含量的影响效能是有限的;水椰八角铁甲可以根据不良的环境条件调节最佳的生理状况,以适应未来的环境和达到最强的适应性。     

Function of Tongue-Playing of Cattle in Association With Other Behavioral and Physiological Characteristics

To study the function of tongue-playing of cattle, this study observed 71 Japanese Black × Holstein steers after feeding in 2 repetitive experiments. The number of steers who performed tongue-playing did not differ among the 3 levels of environmentally enriched pens. Most (90.6%) performances of tongue-playing terminated within 20 min. Frequency of tongue-playing positively correlated with the frequency of resting (r = 0.25, p < .05). Frequency of eating was lower in tongue-playing steers (n = 40) than in non-tongue-playing steers (n = 31; p < .05). Frequencies of self-grooming (p < .05), ruminating (p < .05), and lying ruminating (p < .01) were higher in tongue-playing steers. Plasma dopamine concentration was lower in tongue-playing steers (p < .05). In conclusion, tongue-playing that lasts only for a short time after feeding was induced by behavioral features of steers who rest more and eat hay less at the same time as they perform grooming and ruminating.     

Long‐term after‐effects of cold exposure in adult Alphitobius diaperinus (Tenebrionidae): the need to link survival ability with subsequent reproductive success

1. The effects of cold acclimation and cold exposure on the survival and reproductive capabilities of Alphitobius diaperinus (Tenebrionidae) adult beetles are examined. 2. First, the impact of temperature on survival duration was assessed by placing beetles in a range of cool temperature treatments. Second, the importance of acclimation duration was assessed. Third, the impact of thermal stress on subsequent reproductive ability was examined for beetles that had no previous cold exposure, and for beetles that had been subjected to previous cold exposure (i.e. acclimated) at various conditions, including fluctuating temperatures. 3. In all groups, the number of recorded survivors was strongly impacted by recovery period duration (i.e. 2 vs. 10 days). Survival of non‐acclimated and 3‐day acclimated beetles, expressed as lethal time for 50% of the samples, was reduced significantly when the insects were re‐assessed for survival at 10 days after being returned to optimal growth conditions (7.9 ± 0.4 vs. 5.1 ± 0.6 days and 8.8 ± 0.5 vs. 6.8 ± 0.6 days, respectively). 4. Insects that had been subject to cold acclimation expressed better subsequent reproduction success than non‐acclimated beetles. This beneficial impact increased when the acclimation period was prolonged, but some longer acclimation periods had no significant impact on survival. 5. Our results indicate that cold exposure has the capacity to irreversibly damage the reproductive system and that insect survival depends on the duration of the recovery period. Both the survival ability and subsequent reproductive output have to be examined to objectively determine insect cold resistance.     

Alfalfa water status and cold hardiness as influenced by cold acclimation and water stress

Abstract Water stress at a nonacclimating temperature (18–20°C) increased the cold hardiness of Medicagosativa L. (alfalfa) plants. This increased cold hardiness was retained when the previously water-stressed plants were cold acclimated (2–9°C) in the absence of water stress. Water stress during cold acclimation also increased cold hardiness. Alfalfa was demonstrated to suffer injury, measured as decreased growth following freezing, at sub-lethal temperatures. During cold acclimation the turgor potential (ψ) of watered plants increased, whereas the solute potential and the water content per unit dry weight decreased. The large positive psgrdap of acclimated plants indicates that the decreased water content per unit dry weight is related to an increased proportion of tissue dry matter rather than to tissue dehydration.     

GENITIC VARIABILITY IN TOXIN POTENCIES AMONG SEVENTEEN CLONES OF GAMBIERDISCUS TOXICUS (DINOPHYCEAE)1

Seventeen clones of the ciguatera-causing dinoflagellate Gambierdiscus toxicus Adachi and Fukuyo were acclimated to the same environments over several months. Significant variance components were detected between non-acclimated and acclimated cultures for cell potencies, yields and reproduction rates. The resultant variance in acclimated potencies among clones was statistically significant (P < 0.0001), indicating that potency can be used for genetic comparisons. However, cell potency differences for a clone of G. toxicus in the acclimated vs. non-acclimated phases can exceed genetic differences between clones. This stresses the need for a rigorous acclimation process. Caribbean isolates of G. toxicus were inherently more toxic than isolates from other areas. One Caribbean clone yielded 55 × 10^?4 mu (mouse units)·cell^?1 whereas clones Bermuda, the Bahamas, and Florida ranged from only 1.8 × 10^?4 mu·cell^?1 to a maximum of 19.8 × 10^?4 mu·cell^?1. Toxicity decreased with increasing latitude (r =–0.819, P < 0.01), indicating that environmental differences probably influenced the potencies. A comparison of acclimated reproduction rates at four light intensities also indicated that genetic differences among clones existed. The resulting reproduction rate/light slopes overlapped, indicating that the clones may be adapted to specific light regimes.     

Drought acclimation reduces O2*- accumulation and lipid peroxidation in wheat seedlings

Abiotic stresses cause ROS accumulation, which is detrimental to plant growth. It is well known that acclimation of plants under mild or sub-lethal stress condition leads to development of resistance in plants to severe or lethal stress condition. The generation of ROS and subsequent oxidative damage during drought stress is well documented in the crop plants. However, the effect of drought acclimation treatment on ROS accumulation and lipid peroxidation has not been examined so far. In this study, the effect of water stress acclimation treatment on superoxide radical (O(2)(-z.rad;)) accumulation and membrane lipid peroxidation was studied in leaves and roots of wheat (Triticum aestivum) cv. C306. EPR quantification of superoxide radicals revealed that drought acclimation treatment led to 2-fold increase in superoxide radical accumulation in leaf and roots with no apparent membrane damage. However under subsequent severe water stress condition, the leaf and roots of non-acclimated plants accumulated significantly higher amount of superoxide radicals and showed higher membrane damage than that of acclimated plants. Thus, acclimation-induced restriction of superoxide radical accumulation is one of the cellular processes that confers enhanced water stress tolerance to the acclimated wheat seedlings.     

The protective effect of EGF-activated ROS in human corneal epithelial cells by inducing mitochondrial autophagy via activation TRPM2

Oxidative stress is a major pathogenesis of some ocular surface diseases. Our previous study demonstrated that epidermal growth factor (EGF)-activated reactive oxygen species (ROS) could protect against human corneal epithelial cell (HCE) injury. In the present study, we aimed to explore the role and mechanisms of oxidative stress and mitochondrial autophagy in HCE cells subjected to scratch injury. CCK-8 assays, EdU assays, Western blot analysis, wound-healing assays, and flow cytometry were conducted to determine cell viability, proliferation, protein expression, cell apoptosis, and intracellular ROS levels, respectively. The results showed that EGF could promote damage repair and inhibit cell apoptosis in scratch injured HCE cells by upregulating ROS (**p < .01, ***p < .001). EGF also induced mitochondrial autophagy and alleviated mitochondrial damage. Interestingly, the combination of the mitochondrial autophagy inhibitor and mitochondrial division inhibitor 1 (MDIVI-1) with EGF could reduce cell proliferation, viability, and the ROS level (*p < .05, **p < .01, ***p < .001). Treatment using the ROS inhibitor N-acetyl- l -cysteine abrogated the increase in mitochondrial membrane potential after EGF treatment. (*p < .05). Taken together, these findings indicated that EGF plays an important role in HCE damage repair and could activate ROS to protect against HCE injury by inducing mitochondrial autophagy via activation of TRPM2.