Effect of seasonal thermal stress on oxidative status,immune response and stress hormones of lactating dairy cows

This study aimed to assess the impact of seasonal thermal stress on oxidative stress,immune response,and stress hormones of lactating dairy cows in subtropical regions with different levels of temperature-humidity index(THI).A total of 32 healthy lactating Holstein dairy cows experienced 4 seasons(8 cows/season).The physiological parameters were categorized into low THI(LTHI,THI=42.97±0.95)in winter,moderate THI(MTHI,THI=61.84±0.42)in spring and autumn,and high THI period(HTHI,THI=86.09±0.23)in summer.The blood samples were collected twice in each season to measure oxidative stress,inflammatory and hormonal parameters.Our results showed THI had a positive cor-relation with the rectal temperature(R2=0.821,P<0.001)and respiratory rate(R2=0.816,P<0.001).Dry matter intake,milk yield and fat percentage also significantly differed among groups(P<0.05).Compared with the MTHI group,the LTHI group exhibited a significant increase in malondialdehyde(MDA)level(P<0.001),and the HTHI group displayed a significant increase in levels of cortisol,interleukin(IL)-10,IL-1βand tumor necrosis factor-α(P<0.001).Opposite changes in serum endotoxin and immunoglobulin G levels were observed with the increasing THI(P<0.001).LTHI notably increased the triiodothyronine level,although the thyroxine level was reduced by LTHI and HTHI compared with the MTHI group.In conclusion,LTHI and HTHI conditions may induce different degrees of oxidative stress,inflammation response,and stress hormone imbalances on lactating dairy cows,therefore envi-ronmental management is necessary for the health of dairy cows in extreme weather conditions.

Effects of chilling tolerance induced by spermidine pretreatment on antioxidative activity,endogenous hormones and ultrastructure of indica-japonica hybrid rice seedlings

Spermidine（Spd） is known to be involved in the regulation of plant responses to chilling stress and counteract the adverse effect of stress conditions.Antioxidant activities,endogenous hormones and ultrastructure change under chilling stress were investigated in indica-japonica hybrid rice seedlings.12-d-old seedlings were subjected to exogenous Spd（1 mmol L^（-1）） and then a chilling stress（6℃,4 d） was induced,followed by a subsequent recovery（25℃,4 d）.Results showed that malondialdehyde（MDA） and proline content were enhanced significantly,whereas shoot fresh and dry weights decreased during chilling stress and after recovery;chlorophyll content of chilling-stressed seedlings increased slightly but declined after recovery;additionally,total soluble sugar,sucrose,fructose and starch contents increased significantly during chilling stress,and only soluble sugar and fructose contents were observed in increase after recovery;chilling stress-induced increases in superoxide dismutase（SOD）,peroxidase（POD） and catalase（CAT） activities,but declined after recovery,and the level of ascorbate peroxidase was lower during chilling stress and after recovery;however,endogenous indole-3-acetic acid（IAA）,zeatin riboside（ZR）,gibberellic acid（GA_3）,and abscisic acid（ABA） levels were induced decreased compared with Spd pretreatment.The microscopic analysis revealed that chilling stress-induced destruction of the chloroplast envelope during chilling stress and increased the number of plastoglobuli along with aberrations in thylakoid membranes after recovery.In contrast,exogenous Spd protected rice seedlings from chilling-induced injuries in terms of lower malondialdehyde,proline and carbohydrates accumulation coupled with increased endogenous hormones metabolism.After recovery,Spd pretreatment chilling-exposed seedlings showed higher activities of antioxidant enzymes and normal physiological function of chloroplasts.These results suggest that Spd could promote effectively chilling tolerance which might be largely attributable to the integrity of cell structure and normal metabolism of endogenous hormones in indica-japonica hybrid rice seedlings.

Fermented Lysate of Lactiplantibacillus Isolated From Green Tea Leaves Protects Keratinocytes Against Stress Hormone and Staphylococcus Aureus

Psychological stress can impair epidermal barrier function by inhibiting the proliferation and differentiation of keratinocytes.In this study,the effect of stress hormone on skin microorganisms was confirmed through an in vitro experiment.Cortisol,a typical stress hormone,inhibited the growth of skin microbes,especially Staphylococcus epidermidis,which is a commensal skin microbe.And cortisol enhanced the adhesion of the pathogenic bacterium Staphylococcus aureus to keratinocytes.The fermented lysate of Lactiplantibacillus isolated from green tea leaves(LFL)affected the growth of skin microbes in the opposite manner to cortisol,and increased the expression of a keratinocyte differentiation marker that was suppressed by cortisol and S.aureus.Moreover,LFL inhibited the adhesion of S.aureus to keratinocytes.The modulating effect of LFL on the growth and adhesion of skin microbes was unaffected by the presence of cortisol.LFL also alleviated cell damage in reconstructed human epidermis caused by S.aureus.These results suggest that LFL may be useful as a cosmetic ingredient capable of controlling skin microbiome balance and protecting skin health against psychological stress.

Impact of Adrenaline or Cortisol Injection on Meat Quality Development of Merino Hoggets

Increased levels of stress hormones in the muscle could lead to post mortem metabolic/structural modiifcations that could be relfected on meat quality. The present study investigated the metabolic effect of either adrenaline or cortisol injected into lambs in order to obtain an animal model of acute stress. Results showed that adrenaline or cortisol injection lead to glucose metabolism and muscle temperature increase. Muscle pH immediately post mortem was affected by adrenaline treatment. Water holding capacity （WHC） of fresh muscle, ifnal muscle pH and temperature registered at 24 h post mortem were not affected by injected hormones. Hardness and adhesiveness of LD muscle evaluated 3 d post mortem tended to increase as a result of adrenaline or cortisol injection. Results demonstrated that injected hormones were able to affect the post mortem muscle biochemistry and the pH/T curve independently of ifnal muscle pH.

What can we learn on rodent fearfulness/anxiety from the genetically heterogeneous NIH-HS rat stock?

The “National Institutes of Health” genetically heterogeneous (NIH-HS) rat stock was created in the 1980s through an eight-way cross of as much as possible separate inbred rat strains (i.e. the MR/N, WN/N, WKY/N, M520/N, F344/N, ACI/N, BN/SsN and BUF/N strains) which were readily available at that time. Hansen and Spuhler [1] developed a more naturalistic, genetically heterogeneous rat stock with the aim of optimizing the distribution of genotypic frequencies and recombination and under the hypothesis that the NIH-HS stock could yield a broad-range distribution of responses (broader than commonly used laboratory rat strains) to experimental conditions, and thus serve as a base population for selection studies. Along the last decade, in a series of studies we have phenotypically characterized the NIH-HS rat stock (a colony exists at our laboratory since 2004) for their anxiety/fearfulness profiles (using a battery of both unconditioned and conditioned tests/tasks), as well as regarding their stress-induced hormonal responses, coping style under inescapable stress and spatial learning ability. We have also compared the phenotypic profiles of NIH-HS rats with those of the low anxious RHA-I and the high anxious RLA-I rat strains. The NIH-HS rat stock is, as a population, a rather anxious type of rat, with predominantly reactive/passive coping style in unlearned and learned anxiety/fear tests, and elevated stress hormone responses (as well as enhanced “depressive” symptoms in the forced swimming test). Genetic studies currently under way have thus far revealed that the genetically heterogeneous NIH-HS rat stock constitutes a unique tool for fine mapping of QTL (for multiple behavioural and biological complex traits) to megabase resolution levels, thus enabling candidate gene identification. We give some examples of this in the present paper, while also highlighting that microarray gene expression studies reveal that HPA-axis- and prolactin-related genes (among others) in the amygdala appear to be related with (or associated to) the coping style and anxiety/fearfulness responses of NIH-HS rats.

Characterization and expression analysis of genes encoding Taxol biosynthetic enzymes in Taxus spp.

Taxol(Paclitaxel),an important anticancer drug,is derived at very low yields from Taxus(yew)species that grow very slowly.In the present study,thirteen genes that encode enzymes involved in Taxol biosynthesis in Taxus spp.were analyzed with bioinformatics methods,and their expression levels in different tissues and after cold and hormone treatments were also analyzed.The results indicated that many cis-elements related to abiotic stresses and hormones were found in the promoter sequences of the 8 genes involved in Taxol biosynthesis.Moreover,the 13 enzymes encoded by the target genes were located in different organelles and had many phosphorylation sites in the response proteins.The 13 genes were expressed highly either in roots or in stems,with lower transcripts in needles,and they were highly expressed after treatment with cold,gibberellin,methyl jasmonate or coronatine,consistent with predictions based on the bioinformatics analysis.These results suggest that the factors such as hormones and abiotic stresses stimulate taxane biosynthesis in yews,providing an important way to sustainably generate taxanes from yew trees or their cell cultures to improve Taxol yields.

Salivary Cortisol in an Extreme Non-Competitive Sport Exercise:Winter Swimming

Salivary cortisol role in response to strong stressors implied in extreme exercises and in sport practice was investigated with the aim to verify the claimed benefits that steers winter swimmers to self-prescribe the trials. Specific biochemical data allow to study a variety of stressors in sports and physical exercises, including extreme ones as winter swimming. Salivary cortisol behavior was examined in winter swimmers trials and canoe, canoe-polo competitions and comparisons of results between days with and without performances were reported. Cortisol circadian rhythm in sedentary subjects was collected as control. All the subjects were selected after anamnestic-clinical checks to evaluate their physiological conditions. The circadian cortisol behavior was reported in days with competitions and trials as well as between these events. Abrupt cortisol concentration changes were detected at the time of the trials and competitions: surprisingly, large increasing and decreasing concentrations were detected in both groups. Moreover, in winter swimmers, cortisol concentration remained fairly elevated in the evening of the trial days. In days without competitions, the usual cortisol circadian rhythm was recovered in sportsmen whereas cortisol concentrations persisted at high levels up to the evening in winter swimmers. The view that an extreme sport-like exercise as the winter swimming may well pose some treats ranging from subclinical aspects up to dismetabolic pathologies and even cardiovascular risks is strengthened by results of cortisol trends, suggesting to check physiological conditions. Results demonstrate that well-being feeling can be in contrast to the claimed improvements of health.

Antagonism of Transcription Factor MYC2 by EDS1/PAD4 Complexes Bolsters Salicylic Acid Defense in Arabidopsis Effector-Triggered Immunity

In plant immunity, pathogen-activated intracellular nucleotide binding/leucine rich repeat （NLR） receptors mobilize disease resistance pathways, but the downstream signaling mechanisms remain obscure. Enhanced disease susceptibility 1 （EDS1） controls transcriptional reprogramming in resistance triggered by Toll-lnterleukinl-Receptor domain （TIR）-family NLRs （TNLs）. Transcriptional induction of the salicylic acid （SA） hormone defense sector provides one crucial barrier against biotrophic pathogens. Here, we present genetic and molecular evidence that in Arabidopsis an EDS1 complex with its partner PAD4 inhibits MYC2, a master regulator of SA-antagonizing jasmonic acid （JA） hormone pathways. In the TNL immune response, EDSl/PAD4 interference with MYC2 boosts the SA defense sector independently of EDS1-induced SA synthesis, thereby effectively blocking actions of a potent bacterial JA mimic, coronatine （COR）. We show that antagonism of MYC2 occurs after COR has been sensed inside the nucleus but before or coincident with MYC2 binding to a target promoter, pANAC019. The stable interaction of PAD4 with MYC2 in planta is competed by EDS1-PAD4 complexes. However, suppression of MYC2-promoted genes requires EDS1 together with PAD4, pointing to an essential EDS1-PAD4 heterodimer activity in MYC2 inhibition. Taken together, these results uncover an immune receptor signaling circuit that intersects with hormone pathway crosstalk to reduce bacterial pathogen growth.