Stress Physiology - Science topic

Craig Mckimmie definitely, thanks.

I following the best answer.

Plant Cell, Tissue and Organ Culture (PCTOC), Journal of Plant Biotechnology.

There is no cost for publication, but if you'd like open access is necessary to paid it.

Absolutely I will use such device

Not really

You can see also our work on the E4 validation:

Our results are slightly different from those of Matthijs Noordzij as we found no visual ressemblance between wrist and finger SC, and we found accurate HRV metrics compared to ECG only in motion- and stress-free conditions. Having an adaptation period (e.g., 1 min) before the recording intervals of interest seems to increase the measurement accuracy.

Dear sir,

if I understood right, you want to separate xanthophylls from the more lipiphilic carotins. To do so I would recommend an easy separation procedure: First extract your plant material in ethanol or methanol (not aceton, because this will not form a layer with benzine). After extraction add benzine (best: boiling point 40-60°C). Chlorophylls and carotins will migrate into the benzine phase. Xanthophylls will stay in the alcohol.

You can separate and purify the different xanthophylls e.g. by means of a column chromatography.

Hope this will help

Best regards

Peter Richter

Figured I'd bring this comment back into existence after being dormant for a year; were you able to locate anything, Dr.

Julie Bienertova-Vasku?

thank you very much.

 the study is conducted in two rooms, one was constructed by natural material and another one was constructed by plastic.  we measured  salivary amylase before and after sleep in the two rooms respectively. no significant difference was found between the two rooms either before or after sleeping. and no significant difference was found between before and after sleeping in plastic room. but in natural material room,salivary amylase increased after sleep compared before sleep. because of the material that used for the two rooms were different. many factors must related. however, first of all, i simply want to know dose the increasing of salivary amylase in natural material room mean better sleep quality or worse compared to that in plastic room . 

sincerely

Hi Sophia

We have presently developed a web based scale for stress measurements, but as you know it is time-consuming and expensive  to validate a scale so it is not yet fully “flying” yet.. You are free to use it, perhaps in parallel to some other validated scale.

I do think  the main advantages with the scale are that it is web based and the questions are answered by indicating an emoticon. The battery is done in less than 60 seconds.

This is just an early example. Get in touch if you are interested.- see link

Kind regards

Thorsten

Actually both data formats long and wide is applicable to repeated measures analysis by SPSS. But for beginners I recommend wide data format in which repeated measures are represented on different columns side by side.

As far as I understand from your post, in Example 1:  you have 1 within subject factor (time) and 1 between subjects factor (group). You have weight gain in different periods, you need to enter them in different columns. Since you have also a group variable it will hold another column. So for this dataset you will have 3 columns for repeated measures and one column for group variable. Data structure will be GRP, WGAIN1,WGAIN2,WGAIN3.

In Example 2: you have 2 between subjects factors (gender and group). You need one column for gender, one column for group and one column for outcome, the dependent variable  (the measure you want to test). You need to put dependent variable into Dep Variable box in GLM->Univariate procedure, and the other two factors into Fixed factors box (since they are fixed). There is no dataset attached.

There is an ambiguity about the stress exposed groups you mentioned. Are they repeatedly measured thrice? Or are there three different groups?

It's not clear exactly what you need, as it seems that you have two different issues...the first being how do you ground your faraday cage and all the electronics for your physiology setup, and the second how do you ground your amplifier headstage. If this is correct, the simplest way address the first point in grounding your physiology setup is to get or make a ground terminal block to mount directly (metal to metal contact) on your metal air table (TMC air table, for example). Attach a wire from your faraday cage (if it doesn't directly touch the air table) to the terminal block. Bring a grounding wire from every other piece of electrical equipment, your amplifier rack, and scope to that same grounding terminal point to avoid any ground loop currents. Then do as what was suggested above by Julio and directly connect all that to the ground of a standard outlet.  If you do this, in conjunction with using short shielded cables, you should be able to get a very low noise ephys rig.  For the second point of making a reference electrode, it would depend on your headstage and electrode, and I'm not familiar with your setup.  You may have an integrated unit with multiple recording electrodes and a reference built in.  For most patch clamp setups or tevc setups, you have a headstage that you attach your microelectrode to and you make or buy a Ag/AgCl ground electrode, ground pellet, kcal/agar bridge, etc.,  that attaches to your headstage or amplifier and goes into your bath chamber.

Anyway, I hope this helps.

Good luck!

Speaking from personal experience (and that of other researchers at the Yerkes National Primate Research Center), it seems that cortisol peaks 30-60min after acute social stressors as well.  I work with rhesus monkeys and typically use the human intruder paradigm (invited by Ned Kalin & Steve Shelton at the Uni. of Wisc) as my acute stressors (30min stressor). I've taken blood samples immediately before and after the stressor (Raper et al, 2013 Psychoneuroendo, Raper et al 2013 Horm Beh, Raper et al, 2016 Brain Beh Immun), as well as examined cortisol at 45 min post-stressor (unpublished data) and 24 hours post-stressor (Raper et al, 2016 Brain Beh Immun). I typically do these test at sunrise and/or lights-on, so the baseline/pre-stress cortisol levels are fairly high because of the awakening cortisol response. However, other colleagues and I choose to test at this time of day to avoid any other potential confound, such as the animal having a social conflict earlier in the day prior to testing that I might not be aware of (testing them first thing in the morning avoids that potential confound).   Even with the high basal cortisol I still see a significant increase in cortisol to the acute 30 min stressor, and in a manuscript I'm working on now I see a significant decline in cortisol at 45 min after the stressor has ended.

I'm not sure if the human intruder paradigm will work well for baboons, I know it doesn't work well in African Green Monkeys, they largely just ignore the "intruder" and don't react with cooing, freezing, or hostility that rhesus monkeys exhibit on the task. If the human intruder paradigm won't work for baboons, you might consider a social separation stressor, which is just separating them from their social group and/or cagemate and putting them alone in a novel environment for 30 min. Dettmer et al, 2012 (Psychoneuroendocrinology, 37, 191-199), published on using relocation as a stressor and examined cortisol levels in hair.   Lastly, you could also use pharmacological challenges of the HPA axis (Raper et al, 2014 J Neurosci).

If you have any additional questions please feel free to contact me.  I'm faster at responding if you send me a direct email jraper@emory.edu.

I would suggest measuring CORT in the fecal pellets!

Best wishes, Nina

Effect of Housing Density on Reproductive Parameters and Corticosterone Levels in Nursing Mice

James O'Malley, James M Dambrosia, Judith A Davis

J Am Assoc Lab Anim Sci. 2008 March; 47(2): 9–15. Published online 2008 March.

Analyzing corticosterone metabolites in fecal samples of mice: a noninvasive technique to monitor stress hormones.

Touma C, Palme R, Sachser N.

Horm Behav. 2004 Jan;45(1):10-22.

Dear Ranganathan

First of all you need to check the osmotic potential of your PEG solution through osmometer for accurate research. However, 50g/L creates nearly -0.5 MPa osmotic potential, which induces mild drought stress in plants. I recommend you to use higher osmotic potential solutions (-10 or 1.2 MPa) of PEG 6000 for inducing drought stress. you can also follow our paper in this regard

Hi Elide,

as far as I know, beside cortisol, you can check for other biomarkers related to the hypothalamus-pituitary-adrenal (HPA) axis such as corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH), and neuropeptide Y (NPY, which is not in the HPA but related to sympathetic nervous system (SNS), stress, and resilience too). Also the ratio between these hormones is interesting to study stress.

If you are not interested in just cortisol baselines and how it responds to a stressful task, you can use how cortisol or ACTH respond to dexamethasone.

Also heart rate variability (vs heart rate) has been used.

Complication of vomiting and aspiration is the risk related to anesthesia. Moreover gastrointestinal motility is slow to return after anesthesia. However in case of small and light weight animals there is risk of hypoglycemia so that needs to be monitored and due to this their time of fasting is usually shorter.

Ok, thank you very much Beatrice!!!

Kamakhya Kumar, 

check the link out: 

Please note that all physiological markers of stress have pro's and con's - see e.g. Clemens Kirschbaums writings on individual differences in cortisol reactivity.

I have attached another file on how traumatic stress has been represented in literature. 

Thank you Renzo 

I will contact randy@glasbergen.com

Dear Kushai, 

Check these papers out: 

Hi Victoria,

As Arun mentioned, HRV is a signal that contain stress information because of the ANS natural response. Nevertheless, please consider the HRV contains also physical activity of the ANS so discriminating the psychological stress only requires careful protocols that minimize physical activities. Another point to take into account is that markers extracted from the HRV, traditional analysis (LF/HF), in spite of being widely used may not reveal stress information just because of mathematical limitations of the method, Example here: http://www.asian-nursingresearch.com/article/S1976-1317(14)00070-X/abstract

A case study we have conducted on HRV/ANS response to the meditation as a stress reduction technique reveals interesting results by using non-linear techniques applied to the HRV:

https://www.researchgate.net/publication/282853251_Case_study_on_HRV_-_Real_time_monitoring_of_meditation_shows_surprising_results     

GSR also might be a marker but limitations of this method (physiological and mathematical) are even higher than for the HRV (see attached doc). Also for comparison, cortisol measurement should be taken carefully since it vary during the day.

I cannot comment on the stress and EEG but it seems to me more than challlenging after having performed some measurements in that field...          

Cheers,

Vasile

Dear Hafiz,

Indeed, open-field test is carried out to show the locomotor activity of rodents before Forced Swimming Test (FST) to show that despite the normal locomotion of animals they are immobile in the FST test. I added some reviews that are useful to better understanding the immobility behavior in the FST. Under acute unpredictable and unavoidable stressful conditions, depressed people get despair and hopeless and, in fact, FST mimics similar conditions for rodents in which immobility time is considered as a depressive-like behavior. The Tail Suspension Test is similar to FST as well. Also, Climbing behavior in FST reflects the activity of adrenergic system and swimming is associated with serotonergic system activity.

Cryan, John F., and Andrew Holmes. "The ascent of mouse: advances in modelling human depression and anxiety." Nature reviews Drug discovery 4.9 (2005): 775-790.

Cryan, John F., Rita J. Valentino, and Irwin Lucki. "Assessing substrates underlying the behavioral effects of antidepressants using the modified rat forced swimming test." Neuroscience & Biobehavioral Reviews 29.4 (2005): 547-569.

Slattery, David A., and John F. Cryan. "Using the rat forced swim test to assess antidepressant-like activity in rodents." Nature protocols 7.6 (2012): 1009-1014.

Maybe you could measure free cortisol in the water? However, you may only be able to get relative measures among individuals for each time-point. I'm not entierly sure about how it works, I've only read papers where the method is used... Hard to get individual measurements though, unless you somehow keep the individuals separate (maybe you have to do this anyway, otherwise dominance hierarchies may influence both stress-levels, growth and behaviour as a confounding factor...). Here is a paper, and I guess all the other papers citing it are good sources as well: http://onlinelibrary.wiley.com/doi/10.1111/j.0022-1112.2004.00499.x/full

hello Renee Gs,

you can get the assessment of employees from chapters of HRM books and articles.

usually, the same dimensions and indicators of job analysis and dimenions of employees assessment are  useful for your study. Sometimes there are specific indicators related to the nature of the job practised. so if you design a questionnaire do not neglect the context of the sector or the jobs that are tergeted by your research.

best regards.

Cause Osteoarthritis is complex and multifactorial. It is a result of problems that deriving from the morphology of the cartilage and the mechanical properties of it, as well as changes in the biochemistry of the area.

Few factors that are described as causes of OA are

Anatomical abnormalities

Trauma (either major fractures or microfractures as result of repeated low degree trauma)

Loss of joint stability

Abnormal loading due to alteration of the weight bearing axis

Meniscal surgery (medial meniscectomy almost doubles the incidence of OA)

Altered kinetics of the knee

Gait modification.

Repetitive increase load in a particular area of the knee

Inflammatory factors (increase of them)

Increase of activities of the immune system in the joint environment

Metabolic disorders

Obesity.

In females if they have 6 or more pregnancies.

Vitamin D deficiency (about 2.5 times more OA)

and so on.

All mechanical problems influence the Proteoglycans and all inflammatory problems increase the Proteolytic Enzymes.

Obesity is found to increase the Leptin within the joint which is influencing the chondrocytes.

These are part of the Causes leading to Osteoarthritis and mentioned here in brief.

Thanks again, Tim! :-)

You have received some very interesting answers already, but it seems to me that some of them require a great deal of preparation, learning, money, and time to implement. If you want to keep things simple, you could apply the well-established State-Train Anxiety Inventory, it seems to me.

Mobin,

You might the Life Events Survey for Collegiate Athletes a useful instrument for your purposes. This was developed by Trent Petrie in the early '90s and is included in the paper I am attaching.

Frank

Hello,

corticosteroid administration triggers some physiological pathways. First, hyperglycemia: you can measure circulating glucose. It responds to corticosteroid administration after a short time but remains elevated even after corticosteroid clearance. Second, immune response: corticosteroid administration suppress immune function, especially when administered chronically. Thus, you can measure  circulating immune protein (complement system), lysozyme, immunoglobulins, and acute phase proteins. Also, leukocyte related immune functions could be assayed.

They are the main effects of corticosteroid administration. But, corticosteroid administration also can reduce bone formation (long term osteoporosis),

HI

It a great mistake to use the division physical stress and psychological stress. Stress is stress and it is a very complex phenomenon. It is as two way street. I recommend to read Hans Selye. The father of stress construct.

dear Julie, 

My opinion is that stress in its proper sense involves the activation of the HPA axis. 

Stress is defined as a state of real or perceived threat to homeostasis, which maintenance in the presence of stressors requires activation of  responses involving the endocrine, nervous, and immune systems. 

Dialogues Clin Neurosci. 2006 Dec; 8(4): 383–395.The role of the hypothalamic-pituitary-adrenal axis in neuroendocrine responses to stress

Sean M. Smith, Wylie W. Vale,

One single parameters in Indian context is marital discord which will influence all points.normally marital discord is given 80 points which comes to 300 points as borderline of occupational stress among normal population. HIV positive will itself influence more than 300 points of occupational stress scale. consider this point very carefully you will be able to assess stress very accurately with kind regards. pcg,CLI,chennai

We are used to assess stress in broilers, and in most of birds, the main glococorticoid is CORTICOSTERONE.

I recomend you another question to ask yourself: what kind of stress you want to measure (acute stress associated to some specific situation or chronic stress associated to a global state). Depending on the type of situation you want to evaluate in relation to stress, the matrix chosen should be different. Blood, feahters...

Dear Alexander, 

Cortisol levels peak between 8 and 9 AM

Psychoneuroendocrinology Research Trends

Martina T. Czerbska

Waking up earlier in the morning increases the response.[8]

Shift work: nurses working on morning shifts with very early awakening (between 4:00–5:30 a.m.) had a greater and prolonged cortisol awakening response than those on the late day shift (between 6:00–9:00 a.m.) or the night shift (between 11:00 a.m.–2:00 p.m.).[9] However another study found this attributed this greater respose to increased stress and impaired sleep quality before an early work shift.[10]

Naps: students taking a nap of one to two hours in the early evening hours (between 6:45–8:30 p.m.) had no cortisol awakening response, suggesting cortisol awakening response only occurs after night sleep.[9]

Waking up in the light: cortisol awakening response is larger when people wake up in light rather than darkness.[11][12]

Noise: there is no cortisol rise after nights with traffic-like low-frequency noise.[13]

Alarm clock vs. spontaneous waking: there is no difference on days when people woke up spontaneously or used the alarm clock.[1]

Aspirin has been found to reduce the response probably through an action upon ACTH.[14]

Hi Sakthivel, I previously worked on the effect of early life stress on anxiety, visceral sensitivity and pain in adulthood using rat models.  Early life stress is a major contributory factor to psychopathology later life. Effective maternal care is essential for proper development of the HPA axis (stress axis) – first week is crucial. There are chances that stressing their mother during pregnancy will consequently affect the ability to nurture the pups and this may potentially increase stress (through corticosterone) and cognitive function in adulthood. I believe you may see some significant changes in stress and cognitive function after purberty in pups from stressed mothers compared to controls provided you make use of good experimental paradigm. Good luck!

For further reading, see Lippmann et al. (2007); Wilkinson et al. (2011, 1999) and Sant et al. (1994);Smith et al. ( 2011).

Please let me know if these two articles help:-

1. Generalized anxiety disorder: is there any specific symptom?

Faravelli C1, Castellini G, Benni L, Brugnera A, Landi M, Lo Sauro C, Pietrini F, Rotella F, Ricca V.

Compr Psychiatry. 2012 Nov;53(8):1056-62. doi: 10.1016/j.comppsych.2012.04.002. Epub 2012 May 11.

2. The relationships between measures of stature recovery, muscle activity and psychological factors in patients with chronic low back pain.

Lewis S1, Holmes P, Woby S, Hindle J, Fowler N.

Man Ther. 2012 Feb;17(1):27-33. doi: 10.1016/j.math.2011.08.001. Epub 2011 Sep 7.

Dear colleague,

under normal physiologic circumstances, defense mechanisms prevent the erosion of the upper gastrointestinal mucosal lining by the acidic intraluminal contents. A glycoprotein mucous layer lines the stomach and forms a physical barrier to hydrogen ion back-diffusion. Bicarbonate is trapped in this protective layer and neutralizes hydrogen ions before they can reach the gastric epithelial layer. Adequate perfusion and oxygen delivery maintain intramural pH and prostaglandin synthesis, which is necessary for maintenance of the protective barrier layer. The pathophysiology of stress-related mucosal disease (SRMD) and stress ulceration is complex and the exact mechanisms remain uncertain. Major factors necessary for ulceration are: 1). Low gastric intraluminal pH 2). Upper gastrointestinal tract intramural acidosis, and 3). Increased permeability of the protective mucosal barrier. Gastric intraluminal acidity (pH<4) is necessary for the generation of stress ulceration. Fasting and prolonged gastric transit times may contribute to a more acidic upper gastrointestinal tract. This increased duration and intensity of acid exposure may increase the likelihood of erosions and ulcerations. Reflux of bile salts and enzymes from the duodenum and jejunum may exacerbate mucosal damage. Shock is common in critically ill patients, and septic shock is the most frequent cause of death in intensive care.

Early in the systemic inflammatory response, splanchnic blood flow is reduced in order to preserve midline organs. The result is gastric intestinal mucosal hypoperfusion. This is exacerbated by absolute or relative hypovolemia and arterial hypotension. The intestinal tract possesses a lower capillary density and is unable to recruit capillaries to augment local blood flow to match increases in metabolic needs compared with other tissues. The combination of hypovolemia, redistribution of cardiac output, and intense splanchnic microvascular vasoconstriction results in low perfusion to oxygen demand ratios and subsequent tissue hypoxia. This hypoxia leads to uncoupling of oxidative phosphorylation. Energy is derived from anaerobic glycolysis and ATP hydrolysis, resulting in regional lactic acidosis and a fall in the tissue pH. Hypoperfusion initially causes an ischemic mucosal injury. Accumulation of oxygen free radicals contributes to tissue inflammation and cell death. A reduction in prostaglandin synthesis results in breakdown in the protective mucosal barrier. The epithelial layer is exposed to hydrochloric acid and pepsin, and erosions ensue. Inducible nitric oxide synthetase elevates nitric oxide levels. This causes reperfusion hyperemia and cell death, an enhanced inflammatory response, and gastric and small bowel dysmotility.

Some articles that might be interesting for you:

The aim of this study was to examine the genotypes of RAS genes related to the risk of peptic ulcer and ulcer bleeding among patients taking low dose aspirin.

RAS may play an important role in the development of upper GI mucosal injury induced by low dose aspirin.

 Stollman N et al. Pathophysiology and prophylaxis of stress ulcer in intensive care unit patients. J Crit Care. 2005 Mar;20(1):35-45.

Regards, Matheus Arts

You could look at number of different approaches.

1.   RT-PCR if you know the genes that you are interested in

2.   several Microarrays to look at entire transcriptome

3.   Expression profiling of transcriptomes of wt and the conditions interested in using high-throughput RNA-Seq approaches. (this is the best option as there is a high chance that you would end up with a gold mine, where you could dig deep to find many interesting co expression networks and novel molecular players) 

Here is an example

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0082634 

 Hope this helps you

There are several examples of stress mitigation techniques used in fruit and tree species (e.g. clays, water retention polymers, antitranspirant, antifreeze, etc.).

As an example of radiation management, we could mention the uses of inert clays as kaolinite applied as a suspension to plant canopies forming a film on leaves that increases reflection and reduces absorption of light. Kaolin is a non-abrasive, non-toxic aluminosilicate (Al4Si4O10 (OH)8) clay mineral that has been formulated as a wettable powder for application with conventional spray equipment (Cantore et al., 2009). The use of different formulations of this clay is increasing in agriculture because it has been found that when plants are covered with the mineral, a limitation of thermal stress could be attained (Melgarejo et al., 2004), generating also a moderate consumption of water (Moftah and Al-Humaid, 2005), reducing damage by sunburn (Wand et al., 2006) and limiting the incidence of some pests effects (Knight et al., 2000). Also, photosynthesis of individual leaves is decreased while the photosynthesis of the whole canopy remains unaffected or even increases as a result of effective incident light within the canopy following Kaolin application (Rosati et al., 2007). Hydrogels are also commonly used in forest plantations. There are synthetic superabsorbent polymers generally constituted by water-insoluble highly cross-linked polyacrylamides which can absorb water up to 400 times their own weight when saturated (e.g. Shi et al., 2010; Chirino et al., 2011; Savi et al., 2014). Synthetic polymers have been used in plantation management protecting the roots, since their main characteristic is their high water retention capacity, which reduces irrigation frequency and the loss of chemical products through leaching and washing (e. g. Sojka et al., 2007; Luo et al., 2009). As an example of its effects, application of hydrogel to the rhizosphere of Pinus sylvestris saplings improved the survival rate of plants by 19% during land reclamation (Sarvaš et al., 2007). However, few researches have been conducted treating the use of these resources in the forestry (Boczoń et al., 2009). Water emulsifier organic concentrate with Poly-1-p-Menthene, as the principal functioning agent, have been used on plants as spreader stickers to extend pesticides and lengthen the life of foliar-applied insecticides and fungicides. This kind of compounds could be also used for reducing water transpiration. The soft, flexible film formed after the spray application dries, will significantly reduce moisture lost by the plant foliage. Additionally, this compound could be used to reduce winter damage caused by cold desiccation. Vera-Castillo (1995) found that tested antidesiccants had little overall effect on Ponderosa pine saplings. However, if saplings would have been subjected to greater water stress, the outcome of this research might have been different.

Hi Justin, The correct way is as you comment. First you have to perform an intracardiac perfusion with PBS solution to wash the vascular system, after that, you have to perform a cardiac perfusion of 4% PFA solution. The volume of perfusion will depend of the weight of the rat. For a rat of 250-300 gr the volume of each solution will be approximately 150- 200 ml.

Another great challenge is how to apply the knowledge obtained

to improve the environmental stress tolerance of crops,

a potentially significant benefit of this research. Classical genetics

suggests that plant abiotic stress tolerance is controlled by

multiple loci, each contributing a minor effect (minor genes);

therefore, the manipulation of a master regulatory gene

through biotechnology is considered to be more efficient than

conventional breeding strategies in which it is difficult to break

negative linkage for many loci at one time. Nevertheless, large

gaps remain between basic research and the production of

stress-tolerant crops. First, the standard assays, including screening

criteria and methods, are different between Arabidopsis and

crop species. Proper assessments of environmental stress tolerance

for crops need to be established according to the actual

requirements of agricultural production.

DELLA proteins are also able to promote the expression of

genes encoding reactive oxygen species (ROS)-detoxifying enzymes

to reduce ROS levels in cells after biotic or abiotic attack,

thereby delaying cell death and enhancing tolerance (Achard

et al. 2008b).

Hello! Changes in skin conductance level are often estimated based on area under the curve or PP interval. This chapter might be useful: http://www.imd.inder.cu/adjuntos/article/487/Methods%20in%20Mind.pdf#page=116.

I would also include the root in your investigation. Moreover, you could start with a germination test of different genotypes under increasing salinity.

There is ocean of literature available on this thoroughly beaten-up topic. This is certainly not a question to be raised in the research gate. The answer is voluminous and the mechanism could differ from one plant to the other. Please survey the literature

Another test for investigating anxiety is the Elevated-plus maze - if you are looking for additional behavioural testing procedures! Not unlike the open field test, the elevated-plus maze is founded on the rodent's innate tendency to explore novel environments and avoidance behaviours towards bright, open, vulnerable spaces. Usually, stressed rodents will avoid and spend less time in the open arms of the maze significantly more than non-stressed controls.

Also, just a tip - if you are working with white rodents, I've found using black backgrounds to help ease scoring behaviour when reviewing it on tape.

Mr. Gill, During the stress conditions the plant adapted and resulted in alteration in the concentration of its constituents. In the context to your question, yes absolutely it will alter the phyto-constituent concentration. Meanwhile you need to look the intermediate and enzyme which is utilizing in both the signalling so that you get a correlation on the basis of the availability of the enzyme or the intermediate that is commonly used in both the signalling.

...

Dear Arnold, you have received several helpful suggestions from colleagues. We have utilized the collection of salivary cortisol to answer a number of questions related to the diurnal regulation (rhythmicity), response to stress (responsivity) and moderating factors in children with autism spectrum disorders. While you may not be able to control all potential confounding factors, among the more critical factors that we control for include: food/drink intake (nothing an hour before salivary collection), medications (many can impact the level of cortisol), sleep (use a sleep diary), time of day (utilize a Trackcap devise) and sampling four times per day (immediate waking, 30-min post waking, afternoon and evening 30-min before bedtime). We also employ several statistical approaches to take into consideration intraindividual variability and between-group variablity). For example, we use linear mixed model approaches. If you need more detailed information, I can direct you to specific papers from our lab and others that describe the aforementioned procedures.

Water stress tolerance is relatively measured because that is a multifactorial trait.I think stomatal conductance and osmolytes concentrations are good indicators of water stress tolerance.

Dear Neville,

I have no experience with that ELISA. But you might know that haptoglobin binds hemoglobin and, thereby, induce / stabilize a peroxidase-like function of hemoglobin that you can measure independently from species. This function is used by commercial kits like the kit from BioRepair:

This kit uses a 96-well plate for measurement. But if you want to save money (and have good eyes and no tremor) you can adapt the kit to a 384-well plate. The only prerequisite is that you have no hemolysis in your samples!

Best regards,

Frank