Long-term Stress Conditions Research Articles

Objective Assessments of Mental Fatigue During a Continuous Long-Term Stress Condition.

Prolonged periods of cognitive workload will cause mental fatigue, but objective, quantitative, and sensitive measurements that reflect long-term, stress-induced mental fatigue have yet to be elucidated. This study aims to apply a potential marker of Rényi entropy to investigate the mental fatigue changes in a long-term, high-level stress condition and compare three different instruments for assessment of mental fatigue: EEG, the oddball task, and self-scoring. We recruited nine individuals who participated in a 5-day intellectually challenging competition. The participants were assessed for mental fatigue each day of the competition using prefrontal cortex electroencephalogram (EEG). Reaction time in an oddball task and self-rated scoring were used comparatively to evaluate the performance of the EEG. Repeated measures ANOVA was utilized to analyze the differences among score, reaction time, and wavelet Rényi entropy. The results demonstrated that both wavelet Rényi entropy extracted from EEG and self-rated scoring revealed significant increases in mental fatigue during the 5 days of competition (P < 0.001). The reaction time of the oddball task did not show significant changes during the five-day competition (P = 0.066). Moreover, the wavelet Rényi entropy analysis of EEG showed greater sensitivity than the self-rated scoring and reaction time of the oddball task for measuring mental fatigue changes. In conclusion, this study shows that mental fatigue accumulates during long-term, high-level stress situations. The study also indicates that EEG wavelet Rényi entropy is an efficient metric to reflect the change of mental fatigue under a long-term stress condition and that EEG is a better method to assess long-term mental fatigue.

A type 2 metallothionein (SbMT-2) gene cloned from Salicornia brachiata confers enhanced Zn stress-tolerance in transgenic tobacco by transporting Zn2+ and maintaining photosynthesis efficacy

Metallothioneins are cysteine-rich proteins, which play key roles in metal detoxification, intracellular ion homeostasis maintenance, and protection against intracellular oxidative damage. This study reports the characterization of SbMT-2 cloned from Salicornia brachiata concerning physiology, molecular, and photosynthesis efficiency. Overexpression of SbMT-2 conferred enhanced tolerance to Zn stress in transgenic tobacco supported by increased photosynthesis efficiency and crop quality compared to wild-type. The growth of transgenic and WT plants was comparable in control conditions; transgenic plants showed better growth than WT plants under stress (20 mM ZnSO4 for 30 days). After 30 days of stress, transgenic plants completed their life cycle with early maturation, whereas the WT plants did not and matured very late. About 35 pods with a total weight of 3.5 g per plant were measured in transgenic compared to WT (about 19 pods with total weight 2.5 g). Further, gas exchange and fluorescence measurements established that the SbMT-2 gene improved the photosynthetic efficiency of the transgenic line compared to WT plants during stress conditions. In addition, SbMT-2 might be involved in the selective translocation of Zn2+ under long-term stress condition. Microarray analysis showed that the expression of many Zn transporters, Zn-binding proteins, and Zn-associated proteins encoding genes was up-regulated 4–6 (log2) fold. However the expression of genes encoding other metal-binding proteins, metal metabolism-associated enzymes, and metal-inducible transcription factors were down-regulated. Furthermore, transcript expression analysis elucidated that overexpression of the SbMT-2 gene may regulate the expression pattern of metal transporter encoding genes under stress conditions. Thus, SbMT-2 is an important gene, which plays a positive role by detoxifying reactive oxygen species and maintaining photosynthesis efficiency under Zn stress conditions.

Physical Modeling of Charge Trapping in 4H-SiC DMOSFET Technologies

Silicon carbide (SiC) MOSFETs still exhibit higher drifts of the threshold voltage than comparable silicon devices due to charge trapping, especially regarding small time scales. Understanding this behavior and the consequences in application relevant conditions is therefore of high research interest. Since charge trapping at different defects close to the SiC/ SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> interface and in the bulk oxide is strong bias and temperature-dependent, the phenomenon is referred to as bias temperature instability (BTI). It has been shown that drifts caused by BTI vary both in transient shape and magnitude for commercially available devices. These differences arise from defect densities and properties in the respective technologies. A physical model together with defect parameters that explain the charge transfer reactions at the defects is essential to understand all peculiarities of the transient degradation. In this work, we use a novel method to semiautomatically extract defect parameters within a two-state nonradiative multiphonon model framework. Our work reveals properties of defects responsible for shifts of the threshold voltage for both short-term ac and long-term dc stress conditions which are accurately reproduced for three different DMOS technologies. Our calibrated simulation framework is further used to extrapolate device degradation at operation relevant ac bias conditions to typical device lifetimes.

Antimicrobial Resistance Determinants in Genomes and Plasmids from Acinetobacter baumannii Clinical Isolates.

Acinetobacter baumannii is a Gram-negative coccoid rod species, clinically relevant as a human pathogen, included in the ESKAPE group. Carbapenem-resistant A. baumannii (CRAB) are considered by the World Health Organization (WHO) as a critical priority pathogen for the research and development of new antibiotics. Some of the most relevant features of this pathogen are its intrinsic multidrug resistance and its ability to acquire rapid and effective new resistant determinants against last-resort clinical antibiotics, mostly from other ESKAPE species. The presence of plasmids and mobile genetic elements in their genomes contributes to the acquisition of new antimicrobial resistance determinants. However, although A. baumannii has arisen as an important human pathogen, information about these elements is still not well understood. Current genomic analysis availability has increased our ability to understand the microevolution of bacterial pathogens, including point mutations, genetic dissemination, genomic stability, and pan- and core-genome compositions. In this work, we deeply studied the genomes of four clinical strains from our hospital, and the reference strain ATCC®19606TM, which have shown a remarkable ability to survive and maintain their effective capacity when subjected to long-term stress conditions. With that, our aim was presenting a detailed analysis of their genomes, including antibiotic resistance determinants and plasmid composition.

Adaptation of mitochondrial network dynamics and velocity of mitochondrial movement to chronic stress present in fibroblasts derived from patients with sporadic form of Alzheimer's disease.

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases. Only 10% of all cases are familial form, the remaining 90% are sporadic form with unknown genetic background. The etiology of sporadic AD is still not fully understood. Pathogenesis and pathobiology of this disease are limited due to the limited number of experimental models. We used primary culture of fibroblasts derived from patients diagnosed with sporadic form of AD for investigation of dynamic properties of mitochondria, including fission-fusion process and localization of mitochondria within the cell. We observed differences in mitochondrial network organization with decreased mitochondrial transport velocity, and a drop in the frequency of fusion-fission events. These studies show how mitochondrial dynamics adapt to the conditions of long-term mitochondrial stress that prevails in cells of sporadic form of AD.

First Records of Late Triassic Conodont Fauna and δ13Ccarb from the Dengdengqiao Section, Dangchang County, Gansu Province, Northwestern China

Based on a study of 49 conodont and 57 geochemical samples from the Upper Triassic, carbonate-dominated Dengdengqiao Formation, Qinling Basin, China, the Carnian conodonts and carbon isotope records are first reported. Two genera and four species have been identified amongst 87 conodont elements: Mosherella praebudaensis, Mo. longnanensis sp. nov., Mo. sp., and “Misikella” longidentata. The presence of Mo. praebudaensis indicates that the lower part (bed 2) of the formation is attributable to the Julian (lower Carnian) substage. A radiolarian fauna identified in a previous study belongs to the upper Carnian, but the sampling horizon is unclear. The δ13Ccarb curve shows a ∼1.8‰ negative excursion beginning from upper part of bed 3, but its stratigraphic location is uncertain. The Dengdengqiao Formation is clearly at least partly of Carnian age but could include younger strata. The abundant calcareous algae at the section is probably due to some transport rather than preserved in site. The unusual ecosystem with rare marine organisms may reflect long-term stressful and unfavorable conditions at Dengdengqiao.

Enzyme activities and microbial functional diversity in metal(loid) contaminated soils near to a copper smelter.

The monitoring of soil metal(loid) contamination is of global significance due to deleterious effects that metal(loid)s have on living organisms. Soil biological properties such as enzyme activities (EAs) are good indicators of metal(loid) contamination due to their high sensitivity, fast response, and low-cost. Here, the effect of metal(loid) contamination on physicochemical properties and microbial functionality in soils sampled from within 10km of a Cu smelter is investigated. Soil composite samples were randomly taken within 2, 4, 6, 8 and10km zones from a mining industry Cu smelter. The EAs of dehydrogenase (DHA), arylsulfatase (ARY), β-glucosidase, urease, and arginine ammonification (AA) were studied as indicators of metal(loid) contamination, which included the ecological dose (ED50) with respect to Cu and As contents. The community level physiological profile (CLPP), functional diversity, and catabolic evenness were evaluated based on the C-substrate utilisation. All EAs decreased in zones with high degrees of metal(loid) contamination, which also had low TOC and clay contents, reflecting long term processes of soil degradation. Positive and strong relationships between EAs and TOC were found. DHA and ARY activities decreased by approximately 85-90% in highly metal(loid) contaminated soils. DHA and AA showed significant ED50 values associated with available Cu (112.8 and 121.6mg CuDTPA kg-1, respectively) and total As contents (30.8 and 31.8mg As kg-1, respectively). The CLPP showed different metabolic profiles along the metal(loid) contamination gradients. Long-term stress conditions in soils close to industrial areas resulted in the decreasing of general biological activity, catabolic capacity, and functional diversity.

Survival strategies based on the hydraulic vulnerability segmentation hypothesis, for the tea plant [Camellia sinensis(L.) O. Kuntze] in long-term drought stress condition

Tea plants are important economic perennial crops that can be negatively impacted by drought stress (DS). However, their survival strategies in long-term DS conditions and the accumulation and influence of metabolites and mineral elements (MEs) in their organs, when facing hydraulic vulnerability segmentation, require further investigation. The MEs and metabolites in the leaf, stem, and root after long-term DS (20 d) were examined here, using inductively coupled plasma optical emission spectrometry (ICP-OES) and liquid chromatograph-mass spectrometry (LC-MS). The accumulation patterns of 116 differentially accumulated metabolites (DAMs) and nine MEs were considerably affected in all organs. The concentration of all MEs varied significantly in at least one organ, while the K and Ca levels were markedly altered in all three. Most DAM levels increased in the stem but decreased in the root and leaf, implying that vulnerability segmentation may occur with long-term DS. The typical nitrogen- and carbon-compound levels similarly increased in the stem and decreased in the leaf and root, as the plant might respond to long-term DS by stabilizing respiration, promoting nitrogen recycling, and free radical scavenging. Correlation analysis showed several possible DAM-ME interactions and an association between Mn and flavonoids. Thus, survival strategies under long-term DS included sacrificing distal/vulnerable organs and accumulating function-specialized metabolites and MEs to mitigate drought-induced oxidative damage. This is the first study that reports substance fluctuations after long-term DS in different organs of plants, and highlights the need to use whole plants to fully comprehend stress response strategies.

Treatment of сongenital melanocytic nevus in infants and children by a dual-wavelengths copper vapor laser

Introduction.Congenital melanocytic nevus (CMN) is detected at birth or shortly after birth in 1% of infants. The localization of CMN in aesthetically significant areas causes a decline in child self-esteem and causes concern for his parents. Surgical excision of skin areas with CMN is associated with an increased risk of cosmetic side effects and is often followed by long-term stress conditions after the invasive intervention.&#x0D; Aim of the study.To evaluate the efficacy of the CMN removal in infants, children and adolescents with the dual-wavelengths copper vapor laser (CVL) radiation.&#x0D; Patients and Methods.Medium-sized (up to 9 cm) single CMN was treated in nine fair-skinned patients: seven girls and two boys, aged from 2 months to 16 years. The procedures were carried out at an average CVL power of 0.61.0 W, with a power ratio of 3:2 at 511 nm and 578 nm wavelengths, and an exposure time of 0.20.3 s. Light spot diameter 1 mm. The treatment was carried out during 210 sessions with an interval of 12 months between sessions.&#x0D; Results.In children and adolescents, the treatment of CMN with CVL dual-wavelengths radiation made it possible to achieve significant clarification of the involved area without hypertrophic scars. The duration of the healing of the irradiated area lasted 23 weeks. Side effects were manifested with subtle skin atrophy.&#x0D; Conclusion.The high efficacy of CVL removal of medium-sized CMN in infants and children using the dual-wavelengths CVL radiation without pronounced side effects allows introducing such an approach in the clinical practice of pediatric dermatologists and cosmetologists.

Genome-wide identification of microRNAs and phased siRNAs in soybean roots under long-term salt stress.

Salinity stress, as the key limiting factor for agricultural productivity, can activate a series of molecular responses and alter gene expression in plants. Endogenous regulatory small RNAs, such as microRNAs (miRNAs) and phased siRNAs (phasiRNAs), play crucial roles during stress adaptation and prevent the injury from environmental circumstances. To identify long-term salt stress responsive miRNAs and phasiRNAs as well as their associated genes and pathways in soybean roots. Small RNA and degradome sequencing strategies were applied to genome widely investigate miRNAs and phasiRNAs in soybean roots under control and long-term salt stress conditions. In this study, stringent bioinformatic analysis led to the identification of 253 conserved and 38 novel miRNA candidates. Results of expression profiling, target and endogenous target mimics predictions provided valuable clues to their functional roles. Furthermore, 156 genes were identified to be capable of generating 21 nt and 24 nt phasiRNAs, in which 37 candidates were confirmed by degradome data for miRNA-directed cleavage. Approximately 90% of these phasiRNA loci were protein coding genes. And GO enrichment analysis pointed to "signal transduction" and "ADP binding" entries and reflected the functional roles of identified phasiRNA genes. Taken together, our findings extended the knowledge of salt responsive miRNAs and phasiRNAs in soybean roots, and provided valuable information for a better understanding of the regulatory events caused by small RNAs underlying plant adaptations to long-term salt stress.

Plasma cadmium is associated with increased risk of long-term kidney graft failure

The kidney is one of the most sensitive organs to cadmium-induced toxicity, particularly in conditions of long-term oxidative stress. We hypothesized that, in kidney transplant recipients, nephrotoxic exposure to cadmium represents an overlooked hazard for optimal graft function. To test this, we performed a prospective cohort study and included 672 outpatient kidney transplant recipients with a functioning graft of beyond one year. The median plasma cadmium was 58 ng/L. During a median 4.9 years of follow-up, 78 kidney transplant recipients developed graft failure with a significantly different distribution across tertiles of plasma cadmium (13, 26, and 39 events, respectively). Plasma cadmium was associated with an increased risk of graft failure (hazard ratio 1.96, 95% confidence interval 1.56‒2.47 per log2 ng/L). Similarly, a dose-response relationship was observed over increasing tertiles of plasma cadmium, after adjustments for potential confounders (donor, recipient, transplant and lifestyle characteristics), robust in both competing risk and sensitivity analyses. These findings were also consistent for kidney function decline (graft failure or doubling of serum creatinine). Thus, plasma cadmium is independently associated with an increased risk of long-term kidney graft failure and decline in kidney function. Further studies are needed to investigate whether exposure to cadmium represents an otherwise overlooked modifiable risk factor for adverse long-term graft outcomes in different populations.

Psychological studies of stress experienced by seamen during a long-distance sea voyage#

The issues investigated in the current study pertain to selected psychological aspects of human functioning in long-term stress conditions. Results of the analyses performed in this study have submitted evidence to confirm the hypothesis in which it is stated that staying on the sea for a long time is a difficult situation which contributes - to a greater or smaller extent - to starting the stress process in sailors. The role of interpersonal competencies that has been found most distinct; high level of this variable contributed to reducing both anxiety and the feeling of loneliness. It has been evidenced in the research that the skill of good functioning in varied social groups, which results from high level of development of several traits including: openness, spontaneity, responsibility, and sensitivity, becomes particularly important in long-term difficult situations in which there is little possibility of eliminating the real menace. Another conclusion to be inferred from the research is the one confirming the theoretical suggestion in which the importance of ‘ego strength’ in modifying the course of stress process is emphasised. This personality dimension has turned out to constitute the factor capable of protecting an individual against increase in both anxiety states and the feeling of loneliness during sea isolation. Another issue considered in the current study pertains to defining the role of ‘family variable’ in mediating the course of stress process under conditions of long-term task isolation. The analyses have confirmed the hypothesis in which it was assumed that sailors functioning in family systems characterised by high level of integration and quality, experience lower emotional costs during a voyage. Generally, it may be claimed that - according to the research results of the study - ‘family variables’ may constitute a significant predictor of both the ‘quality’ of a man’s functioning and personal costs he experiences in long-term stress conditions.

Regulation of phenylpropanoid biosynthesis by MdMYB88 and MdMYB124 contributes to pathogen and drought resistance in apple

MdMYB88 and MdMYB124 have been demonstrated to be responsible for lignin accumulation in apple under drought stress. In this study, using a metabolomic approach, we identified differentially accumulated phenylpropanoid and flavonoid metabolites in MdMYB88/124 transgenic RNAi plants under control and long-term drought stress conditions in apple roots. We confirmed the regulation of phenylalanine by MdMYB88 and MdMYB124 via UPLC-MS in apple roots under both control and drought conditions. Using Electrophoretic Mobility Shift Assay (EMSA) and ChIP-quantitative PCR (qPCR) analyses, we found that MdMYB88 positively regulates the MdCM2 gene, which is responsible for phenylalanine biosynthesis, through binding to its promoter region. Under long-term drought conditions, MdMYB88/124 RNAi plants consistently accumulated increased amounts of H2O2 and MDA, while MdMYB88 and MdMYB124 overexpression plants accumulated decreased amounts of H2O2 and MDA. We also examined the accumulation of metabolites in the phenylpropanoid biosynthesis pathway in the leaves of MdMYB88 and MdMYB124 transgenic apple plants after long-term drought stress. We found that metabolites responsible for plant defense, including phenylpropanoids and flavonoids, accumulated less in the RNAi plants but more in the overexpression plants under both control and drought conditions. We further demonstrated that MdMYB88/124 RNAi plants were more sensitive to Alternaria alternata f. sp. mali and Valsa mali, two pathogens that currently severely threaten apple production. In contrast, MdMYB88 and MdMYB124 overexpression plants were more tolerant to these pathogens. The cumulative results of this study provided evidence for secondary metabolite regulation by MdMYB88 and MdMYB124, further explained the molecular roles of MdMYB88 and MdMYB124 in drought resistance, and provided information concerning molecular aspects of their roles in disease resistance.

The effect of short-term vs. long-term soil moisture stress on the physiological response of three cocoa (Theobroma cacao L.) cultivars

Understanding water stress signaling mechanisms and screening for tolerant cocoa cultivars are major challenges when facing prolonged dry and rainy seasons in cocoa-producing areas. While abscisic acid (ABA) and proline are supposed to enhance drought tolerance in cocoa, the role of polyamines remains unclear. The aim of this study was to investigate the biochemical response and phenological adaptation of cocoa (Theobroma cacao) on different soil moisture conditions, with a focus on short-term (20 days) and long-term (89 days) stress conditions, and to compare the performance of three cocoa cultivars. In a split plot design with four blocks, cocoa seedlings of an international high-yielding cultivar (TSH-565) and two locally selected cultivars (IIa-22 and III-06) from the drought-exposed Alto Beni region, Bolivia, were arranged in pots under a roof shelter (cultivar: three levels). The seedlings were exposed to strong (VERY DRY) and moderate (DRY) soil moisture deficits, water logging (WET) and regular irrigation (MOIST) that served as a control (moisture: four levels). We examined the growth performance and the levels of ABA, proline, and polyamines in the leaves. Growth was reduced already at a moderate drought, while severe drought enhanced seedling mortality. Severe drought increased the levels of ABA by 453% and of proline by 935%, inducing a short-term stress response; both compounds were degraded over the long-term period. The polyamine concentration was unrelated to soil moisture. The cocoa cultivars did not differ in their biochemical response to soil moisture stress (proline: p-value = 0.5, ABA: p-value = 0.3), but the local cultivar III-06 showed a stronger height growth increment than the international cultivar TSH-565 (237%, p-value = 0.002) under drought conditions.

It’s getting hairy – External contamination may affect the validity of hair cortisol as an indicator of stress in pigs and cattle

Hair cortisol concentration (HCC) is increasingly used for the assessment of enhanced hypothalamic–pituitary-adrenal (HPA) axis activity, e.g., caused by repeated or long-term stressful conditions or pathologies. However, there is still a lack of knowledge regarding the mechanisms and sources of cortisol incorporation into the hair and possible confounding factors, especially in non-human animals. Farm animals are usually kept under confined housing conditions, have close contact with each other and with soiled environments and may thus be exposed to contamination with urine, feces and saliva, which are known to contain substantial concentrations of cortisol or its metabolites. Therefore, the aim of our study was to investigate the impact of contamination with urine, feces and saliva on the cortisol concentration in the hair of pigs and cattle. In an in vitro experiment, hair strands of 12 pigs and 12 cattle were repeatedly contaminated with urine and saliva, containing either low or high cortisol concentrations, or with the feces of the respective species and were compared with hair treated with water or untreated hair. Contamination was performed over 20 days for two hours daily. Thereafter, all samples were washed, ground, extracted and analyzed for HCCs following the same protocol. Our results showed that contamination with urine caused a considerable and concentration-dependent increase in HCCs in both species. Saliva had a comparable effect only in cattle. In addition, the treatment with water led to a reduction in the cortisol concentration of porcine hair, whereas contamination with feces caused an increase in HCC only in cattle. Our findings provide evidence that contamination of hair with cortisol-containing body fluids causes incorporation of cortisol into the hair shaft, probably via diffusion depending on the concentration gradient. In that case, cortisol in hair derived from contamination cannot be distinguished from cortisol originating from blood. Thus, contamination may affect the validity of hair cortisol as an indicator of HPA axis activity and cannot be prevented by decontamination protocols prior to analysis.

Carbohydrate and plant hormone regulate the alkali stress response of hexaploid wheat (Triticum aestivum L.)

Most types of stress influence crop plants at intervals. Unlike other stresses, salt and alkali stresses influence crop plants for their entire life cycle. However, little is known about physiological and molecular response of crop plants to long-term salinity or long-term alkali stress (LAS) condition. In the present study, we subjected hexaploid wheat seeds to LAS treatment (NaHCO3/Na2CO3, 9:1; 50 mM, pH 8.7) across the germination and seedling stages for 30 days. To elucidate gene expression and physiological adaptation strategies of wheat plants to LAS, we measured the anatomy, plant hormones, compatible solutes, inorganic ions, and transcriptomic profiling of control plants and stressed plants. The results showed that LAS strongly influenced the signaling transduction systems involved in plant hormone. Although LAS did not decrease concentrations of jasmonic acid (JA), salicylic acid (SA) and indole-3-acetic acid (IAA) in leaves of hexaploid wheat, LAS upregulated expression of AUX/IAA gene (suppressor of IAA pathway) and JAZ gene (suppressor of JA pathway), as well as downregulated expression of TGA and PR-1 genes (core genes of SA pathway). We propose that hexaploid wheat may suppress the IAA, JA, and SA signaling pathways in leaves via regulating expression of down-stream key genes not via altered concentrations of these plant hormones. The suppression of the IAA, JA, and SA signaling pathways may shift energy from general metabolism to stress response. The upregulation of protective protein genes (LEA and dehydrin) and the accumulation of carbohydrates may relieve Na+ toxicity in cytosol under LAS. In addition, under LAS, in most salinity-tolerant triads, A, B, and D homeologs had similar expression levels and exerted a dosage effect. Such dosage effects may contribute to the development of strong alkali tolerance of hexaploid wheat because function of most critical stress tolerance proteins relies on their absolute abundance.

Lost in Translation: Physiological Roles of Stored mRNAs in Seed Germination

Seeds characteristics such as germination ability, dormancy, and storability/longevity are important traits in agriculture, and various genes have been identified that are involved in its regulation at the transcriptional and post-transcriptional level. A particularity of mature dry seeds is a special mechanism that allows them to accumulate more than 10,000 mRNAs during seed maturation and use them as templates to synthesize proteins during germination. Some of these stored mRNAs are also referred to as long-lived mRNAs because they remain translatable even after seeds have been exposed to long-term stressful conditions. Mature seeds can germinate even in the presence of transcriptional inhibitors, and this ability is acquired in mid-seed development. The type of mRNA that accumulates in seeds is affected by the plant hormone abscisic acid and environmental factors, and most of them accumulate in seeds in the form of monosomes. Release of seed dormancy during after-ripening involves the selective oxidation of stored mRNAs and this prevents translation of proteins that function in the suppression of germination after imbibition. Non-selective oxidation and degradation of stored mRNAs occurs during long-term storage of seeds so that the quality of stored RNAs is linked to the degree of seed deterioration. After seed imbibition, a population of stored mRNAs are selectively loaded into polysomes and the mRNAs, involved in processes such as redox, glycolysis, and protein synthesis, are actively translated for germination.

SUN-309 PLASMA CADMIUM AND RISK OF LATE GRAFT FAILURE AND KIDNEY FUNCTION DECLINE IN KIDNEY TRANSPLANT RECIPIENTS

The kidney is the most sensitive organ to cadmium-induced toxicity, particularly in conditions of long-term ongoing oxidative stress. We hypothesized that, in kidney transplant recipients (KTR), the nephrotoxic exposure to cadmium represents an overlooked hazard for preserved graft functioning. We performed a longitudinal cohort study of 672 adult KTR with a functioning graft ≥1 year, recruited at a university setting (2008-2011). A Kaplan-Meier curve, log-rank test, and multivariable-adjusted Cox proportional-hazards regression analyses were performed to assess the prospective association of plasma cadmium with the primary endpoint death-censored graft failure (defined as restart of dialysis or re-transplantation) and the secondary endpoint kidney function decline (defined as doubling of serum creatinine or graft failure). Subgroup prospective analyses were performed according to significant effect-modifiers. Median plasma cadmium was 58 (IQR, 43‒75) ng/L. During 4.9 (IQR, 3.4‒5.5) years of follow-up, 78 KTR developed graft failure (13, 26, and 39 events across tertiles of cadmium; P<0.001). Plasma cadmium associated with increased risk of graft failure (HR 1.96, 95% CI 1.56‒2.47 per 2log ng/L; P<0.001), particularly among patients with abnormal liver enzyme levels (HR 2.62, 95% CI 1.73‒3.95 per 2log ng/L; P<0.001). A dose-response relationship was observed, with a HR of 2.67 (95% CI 1.36‒5.26 per 2log ng/L; P<0.001) and 4.31 (95% CI 2.25‒8.22 per 2log ng/L; P<0.001) for patients in tertile 2 and 3 of plasma cadmium distribution, respectively. Our findings were independent of adjustment for donor, recipient, and transplant characteristics, robust in sensitivity analyses without outliers, and consistent over the secondary end-point kidney function decline. A seemingly significant association of cadmium with all-cause mortality was lost in graft failure-censored analyses.Table 1Association of plasma cadmium with risk of death-censored graft failure (nevents=78) and kidney function decline (nevents=95)ModelsCadmium per 2log (ng/L)HR (95% CI)P valueDeath-Censored Graft FailureCrude1.89 (1.47‒2.43)<0.001Model 11.96 (1.56‒2.47)<0.001Model 21.96 (1.40‒2.75)<0.001Model 31.96 (1.40‒2.76)<0.001Model 42.01 (1.45‒2.79)<0.001Kidney Function DeclineCrude1.66 (1.29‒2.15)<0.001Model 11.78 (1.41‒2.26)<0.001Model 21.77 (1.28‒2.44)0.001Model 31.75 (1.27‒2.42)0.001Model 41.75 (1.27‒2.42)<0.001 Open table in a new tab Multivariable model 1 was adjusted for age and sex. Subsequently, additive adjustment was performed for eGFR, proteinuria, primary kidney disease, transplant vintage, acute rejection, cold ischemia time, human leukocyte antigens mismatches, and deceased donor status (model 2); body mass index, systolic blood pressure, blood glucose, and presence of diabetes (model 3); and, smoking and alcohol use (model 4). View Large Image Figure ViewerDownload Hi-res image Download (PPT) In KTR, plasma cadmium is independently associated with increased risk of kidney function decline and late graft failure. Cadmium-targeted interventions may represent novel risk-management strategies to decrease the burden of late kidney graft failure.

Within a hair’s breadth – Factors influencing hair cortisol levels in pigs and cattle

During the last two decades, hair cortisol concentration (HCC) has proven to be a promising marker for the evaluation of increased hypothalamic-pituitary-adrenal axis activity caused by repeated or long-term stressful conditions. A minimally invasive sampling procedure, simple storage and the retrospective characteristic of one hair sample are reasons why HCC is increasingly used not only in human medicine but also in animal welfare research. However, before applying HCC as a reliable indicator for stress, it is important to investigate potential influencing factors in addition to stressors in the species of interest. Thus, the aim of our study was to elucidate the impact of age, sex, hair color, body region, age of hair segments and season of hair sampling on HCC in pigs and cattle. Hair samples were taken by electric clippers and analyzed by ELISA after extraction. Our results show similar effects of influencing factors in both species. Significantly increased HCCs were found in young animals after birth compared with older age groups. In addition, HCCs were significantly higher in samples obtained from the tail tip in comparison with samples from the shoulder, neck and back regions, in black hair compared with white hair and in distal hair segments. Season had an impact on HCC only in cattle, which exhibited higher levels in winter than in summer. In conclusion, age, body region, hair color, hair segment and season affect hair cortisol concentrations and should be considered and controlled for when HCC is applied as a potential stress indicator in pigs and cattle. In addition, further research is necessary to elucidate the mechanisms by which cortisol is incorporated into the hair shaft.

Seawater salt-trapped Pseudomonas aeruginosa survives for years and gets primed for salinity tolerance

BackgroundIn nature, microorganisms have to adapt to long-term stressful conditions often with growth limitations. However, little is known about the evolution of the adaptability of new bacteria to such environments. Pseudomonas aeruginosa, an opportunistic pathogen, after natural evaporation of seawater, was shown to be trapped in laboratory-grown halite crystals and to remain viable after entrapment for years. However, how this bacterium persists and survives in such hypersaline conditions is not understood.ResultsIn this study, we aimed to understand the basis of survival, and to characterise the physiological changes required to develop salt tolerance using P. aeruginosa as a model. Several clones of P. aeruginosa were rescued after 14 years in naturally evaporated marine salt crystals. Incubation of samples in nutrient-rich broth allowed re-growth and subsequent plating yielded observable colonies. Whole genome sequencing of the P. aeruginosa isolates confirmed the recovery of the original strain. The re-grown strains, however, showed a new phenotype consisting of an enhanced growth in growing salt concentration compared to the ancestor strain. The intracellular accumulation of K+ was elicited by high concentration of Na+ in the external medium to maintain the homeostasis. Whole transcriptomic analysis by microarray indicated that 78 genes had differential expression between the parental strain and its derivative clones. Sixty-one transcripts were up-regulated, while 17 were down-regulated. Based on a collection of single-gene knockout mutants and gene ontology analysis, we suggest that the adaptive response in P. aeruginosa to hyper-salinity relies on multiple gene product interactions.ConclusionsThe individual gene contributions build up the observed phenotype, but do not ease the identification of salinity-related metabolic pathways. The long-term inclusion of P. aeruginosa in salt crystals primes the bacteria, mediating a readjustment of the bacterial physiology to growth in higher salt concentrations. Our findings provide a starting point to understand how P. aeruginosa, a relevant environmental and pathogenic bacterium, survives to long-term salt stress.