This work was supported by the Auburn University fund FOP 101002-139294-2050.

All experimental procedures were approved by IACUC of Auburn University, Auburn, Alabama.
1. Preparation of Culture Media, Dishes and Bacterial Culture
<ol>
	<li>Inoculate 10 ml of nutrient broth in a flask with a single colony of Bacillus subtilis BSB3 culture, grown overnight on a nutrient agar plate.</li>
	<li>Make 500 ml of sporulation medium19 (per liter: Bacto Nutrient Broth, 8 g; 10% (w/v) KCl, 10 ml; 1.2% (w/v) MgSO4 x 7H2O, 10 ml; agar, 15 g) and autoclave at 121 oC for 20 min. Allow to cool to 50 oC and add the following sterile solutions:1 M Ca(NO3)2, 1 ml; 0.01 M MnCl2, 1 ml; 1 mM FeSO4, 1 ml.</li>
	<li>Cool prepared medium to 40 oC for 20 min at room temperature and pour 25 ml into each of 20 sterile Petri dishes in the sterile cabinet. Let the medium solidify overnight.</li>
	<li>Spread 0.5 ml of overnight culture of Bacillus subtilis BSB3 onto the surface of the medium in the Petri dishes. Incubate culture at 37 oC for 5 days until 90% sporulation. Reveal phase-bright spores by high resolution microscopy.</li>
	<li>Harvest bacteria by adding 1 ml of sterile phosphate buffered saline (PBS) to the plate and scraping bacteria from a surface using a sterile cell spreader. Store the suspension in the refrigerator until needed.</li>
	<li>Confirm viability of bacteria by plating 0.1 ml of the appropriate dilution (10-5 to 10-6) of a bacterial suspension on sporulation medium plates followed by incubation for 18 - 24 hr at 37 oC.</li>
	<li>Count bacterial colonies on the plates using a colony counter and calculate the titer of bacteria in the tested suspension. Prepare bacterial suspension with the final concentration 1 x 108 CFU/ml in PBS.</li>
</ol>
2. Animals
<ol>
	<li>Use 32 male Sprague&#8211;Dawley rats (250 - 300 g). Maintain animals under specific pathogen-free conditions with free access to standard pellet chow and water. Establish a mean temperature (21 &#177; 1 oC), humidity (50 &#177; 5%) and a 12 hr light-dark cycle.</li>
</ol>
3. Experimental Design
<ol>
	<li>Start treatment of animals by oral gavage11, after 2 days of acclimatization. Use syringe with the oral gavage needle. Treat 16 rats with B. subtilis BSB3 suspension (1 ml per rat) twice a day for two days (B. subtilis group). Treat 16 rats with PBS (1 ml per rat) twice a day for two days (PBS group) (Figure 1).</li>
	<li>After treatment, subdivide each group (8 rats per group): Group 1- control (PBS/no stress), Group 2- B. subtilis (B. subtilis /no stress), Group 3- stress (PBS/heat stress) and Group 4- B. subtilis + stress (B. subtilis/heat stress).</li>
	<li>Measure the rectal temperature of each rat using an electronic digital thermometer. Keep rats of groups 1 and 2 at room temperature for 25 min. Place animals of groups 3 and 4 in a climate chamber at 45 oC and relative humidity 55% for 25 min.</li>
	<li>Afterwards, measure the rectal temperature of each rat in all groups using an electronic digital thermometer. Place all animals at room temperature for 4 hr.</li>
	<li>Anesthetize rats with isoflurane (2 - 4%) in a sealable anesthesia jar and observe until the rats are deeply anesthetized (absence of response to toe pinch). Euthanize rats by rapid decapitation with a guillotine.</li>
	<li>Collect trunk blood from each rat20 (15 - 16 ml) with the apyrogenic pipettes into apyrogenic tubes to obtain serum and immediately take samples of blood (7 &#181;l from each rat) with a pipette for microscopic examination.</li>
	<li>Put tubes with the blood in a refrigerator for at least 30 min to allow clotting. Centrifuge tubes at 20 oC, 7,000 x g for 10 min and quickly remove serum with a pipette. Aliquot serum obtained from each rat into 50 &#181;l volumes and store at -20 oC until assay.</li>
</ol>
4. Surgical Procedure
<ol>
	<li>Cut/trim all fur from the abdomen and thorax of the underside of the carcass with electric shears. Place the carcass in a sterile cabinet and treat the shaved surface of the carcass with 70% alcohol.</li>
	<li>Use a sterile scalpel to create a midline incision of the abdomen. Remove liver, mesenteric lymph nodes, spleen and small intestine from each rat using sterile tweezers.</li>
</ol>
5. Analysis of Bacterial Translocation&#160;
<ol>
	<li>Place each sample of liver, mesenteric lymph nodes and spleen into pre-weighed sterile tubes and weigh. Calculate the weight of the sample as a difference between the weight of a tube with a sample and the weight of an empty tube.</li>
	<li>Add sterile PBS to the tube to obtain a 1:10 dilution (w/v) of the sample and homogenize each sample with a sterile glass tissue homogenizer to obtain a homogeneous suspension21.</li>
	<li>Make serial dilutions (10-1 to 10-4) of each sample in sterile PBS. Plate 0.1 ml of all dilutions of each tissue onto surface of MacConkey&#39;s and 5% blood agar and Brucella blood agar with hemin (0.005 g/L) and vitamin K1 (0.01 g/L) plates.</li>
	<li>Incubate MacConkey&#39;s and 5% blood agar plates aerobically and Brucella blood agar plates under anaerobic conditions at 37 oC22.</li>
	<li>Count colonies of aerobic bacteria after 24 hr, and colonies of anaerobic bacteria after 48 hr of incubation using a colony counter. Express the results as the number of colony-forming units (CFU) in a gram of tissue.</li>
</ol>
6. Histological Analysis&#160;
<ol>
	<li>Remove small intestine samples from each rat by the surgical procedure (steps 4.1 - 4.2). Fix samples in Bouin&#8217;s Fixative, embed in paraffin, prepare 6 &#181;m sections and stain sections with hematoxylin and eosin using standard procedures23.</li>
	<li>Use a high-resolution microscope system for measuring height of intestinal villi and total mucosal thickness in each sample (magnification 100X)24. Analyze 4 samples from each rat and make at least twenty measurements in each sample. Express results in micrometers.</li>
</ol>
7. Cytokine Assay
<ol>
	<li>Use commercial rat ELISA kits for IL-1&#946;; IL-6; TNF-&#945;; INF-&#947;, and IL-10 to measure levels of cytokines in serum according to manufacturer&#8217;s protocol.</li>
	<li>Generate standard curves for each set of samples assayed using standards for the relevant kit. Define the level of cytokines in each sample by comparison of experimental data with the appropriate standard curve.</li>
</ol>
8. Lipopolysaccharide Assay
<ol>
	<li>Analyze level of LPS in serum using a rat LPS ELISA kit according to manufacturer&#8217;s protocol. Estimate concentration of LPS in samples by comparison of the obtained values with the values of the standard curve.</li>
</ol>
9. High Resolution Light Microscopy of Blood
<ol>
	<li>Use the microscope system described previously25,26. Use a vibration isolation platform as a base for the microscope system and video camera and computer25 to record the live images. Calibrate test images using a Richardson slide as previously described27.</li>
	<li>Place 7 &#181;l of freshly drawn blood from each rat on a glass slide, coverslip, photograph and record ten image frames of 72 &#215; 53.3 &#181;m2 in each sample (magnification 1,700X).</li>
	<li>Measure the concentration of vesicles using software which provides high-resolution direct-view optical images in real time. Examine a minimum of 20 image frames for each experimental condition28.</li>
</ol>
10. Statistics
<ol>
	<li>Express all values as mean and standard deviation. Perform statistical analysis and graph plotting. Analyze the results with the two sample t-test, set the significance level at 0.05 to define statistical significance.</li>
</ol>

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The authors declare that they have no competing financial interests.

Exposure to high temperature results in serious health conditions29. Prevention and early detection of complications related to heat stress are of vital importance30. The presented protocol can be used to evaluate the efficacy of various approaches for the prevention of heat stress adverse effects.
Critical steps within this protocol include: the heat treatment procedure (45 oC, 25 min); the usage of apyrogenic materials during collection and p...

Different stressors affect human and animal health. Temperature is one of the most stressful factors, causing chronic, acute and even lethal illnesses1. Changes in intestinal morphology and a loss of gut barrier integrity after heat stress were documented in many cases2,3. This protective barrier is responsible for defense against translocation of gut bacteria and their toxins, in particular lipopolysaccharides (LPS), from the lumen to the internal circulation4,5. Stability of the gut microbiota significantly influences intestinal barrier function, the immune response of the host, and tolerance to stress conditions6. Thus, modulation of the intestinal microbiota can provide a novel approach for prevention of stress-related adverse effects. 
Beneficial bacteria have been used as a promising strategy to modify the gut microbiota for successful management of various clinical conditions, such as diarrhea, inflammatory bowel disease, atopic dermatitis, metabolic disorders7-10. Probiotic effects of beneficial bacteria include production of essential metabolites to support intestinal health, stimulation of the immune system, promotion of lactose tolerance, restoration of epithelial dysfunction. Probiotics were effective in prevention of the stress-related complications in vitro and in animal models11,12. 
Researchers have given more attention to Bacillus bacteria as probiotics because these bacteria support intestinal homeostasis13 and have beneficial effects on the host14. Our previous data demonstrated high efficacy of Bacillus probiotics against pathogens in vitro15,16 and in clinical trials17,18. Here, we aim to evaluate the preventive effect of B. subtilis BSB3 strain against complications after heat stress.

<table><tbody><tr><td>Phosphate buffered saline (PBS)</td><td>Sigma-Aldrich,&amp;nbsp;St. Louis, MO</td><td>P4417</td><td></td></tr><tr><td>Ethyl Alcohol&amp;nbsp;</td><td>Pharmco products Inc. Brookfield, CT, USA&amp;nbsp;</td><td>64-17-5</td><td></td></tr><tr><td>Agar</td><td>VWR</td><td>97064-334</td><td></td></tr><tr><td>MacConkey agar plates</td><td>VWR</td><td>470180-742</td><td></td></tr><tr><td>5% blood agar plates</td><td>VWR</td><td>89405-024</td><td></td></tr><tr><td>Brucella blood agar plate with Hemin, and Vitamin K</td><td>VWR</td><td>89405-032</td><td></td></tr><tr><td>Bouin&amp;rsquo;s Fixative</td><td>Electron Microscopy Sciences, Hatfield, PA, USA</td><td>15990</td><td></td></tr><tr><td>IL-10 Rat ELISA kit</td><td>Invitrogen, Camarillo, CA, USA</td><td>KRC0101</td><td></td></tr><tr><td>IL-1beta Rat ELISA Kit</td><td>Invitrogen, Camarillo, CA, USA</td><td>KRC0011</td><td></td></tr><tr><td>IL-6 Rat ELISA Kit</td><td>Invitrogen, Camarillo, CA, USA</td><td>KRC0061</td><td></td></tr><tr><td>INF-gamma Rat ELISA Kit</td><td>Invitrogen, Camarillo, CA, USA</td><td>KRC4021</td><td></td></tr><tr><td>TNF-alpha Rat ELISA Kit</td><td>Invitrogen, Camarillo, CA, USA</td><td>KRC3011</td><td></td></tr><tr><td>Rat LPS ELISA Kit</td><td>NeoBioLab, MA, USA</td><td>RL0275</td><td></td></tr><tr><td>Environmental Chamber 6020-1</td><td>Caron, Marietta, OH, USA</td><td>6020-1</td><td></td></tr><tr><td>Centrifuge&amp;nbsp;</td><td>Beckman Coulter, Indianapolis, IN, USA</td><td>Optima L-90K</td><td></td></tr><tr><td>Ultra Centrifuge</td><td></td><td></td><td></td></tr><tr><td>Light microscope optical system</td><td>CitoViva Technology Inc., Auburn, AL</td><td></td><td></td></tr><tr><td>Colony counter</td><td>Fisher Scientific , Pittsburgh, PA, USA</td><td>RE-3325</td><td></td></tr><tr><td>Freezer</td><td>Haier, Brooklyn, NY, USA</td><td>HCMO50LA</td><td></td></tr><tr><td>Ultra microplate reader</td><td>Bio-Tek Instrument, Winooski, VT, USA</td><td>ELx 808</td><td></td></tr><tr><td>Auto Strip Washer</td><td>Bio-Tek Instrument, Winooski, VT, USA</td><td>ELx50</td><td></td></tr><tr><td>Pipettes</td><td>Gilson, Pipetman, France</td><td>P100, P200, P1000</td><td></td></tr><tr><td>C24 Incubator Shaker</td><td>New Brunswick Scientific, Enfield, CT, USA</td><td>Classic C24</td><td></td></tr><tr><td>Rocking Shaker&amp;nbsp;</td><td>Reliable Scientific, Inc., Nesbit, MS, USA</td><td>55</td><td></td></tr><tr><td>Petri dishes</td><td>Fisher Scientific, Pittsburgh, PA, USA</td><td>875713</td><td>100 mm x 15 mm</td></tr><tr><td>SterilGard III Advance</td><td>The Baker Company, Sanford, ME, USA</td><td>SG403</td><td></td></tr><tr><td>Culture Growing Flasks</td><td>Corning Incorporated, Corning, NY, USA</td><td>4995</td><td>PYREX 250 ml Erlenmeyer flasks</td></tr><tr><td>Optical Spectrometer Genesys 20</td><td>Thermo Scientific, Waltham, MA, USA.</td><td>4001</td><td></td></tr><tr><td>Sony DXC-33 Video camera</td><td>Sony</td><td></td><td></td></tr><tr><td>Richardson test slide</td><td>Electron Microscopy Science, Hatfield, PA, USA</td><td>80303</td><td></td></tr><tr><td>Millipore water purification system</td><td>Millipore</td><td>Direct-Q</td><td></td></tr><tr><td>Image-Pro Plus software</td><td>Media Cybernetics, MD, USA</td><td></td><td></td></tr><tr><td>Triple Beam Balance</td><td>OHAUS Corporation, Parsippany, NJ, USA</td><td></td><td></td></tr><tr><td>Tissue Homogenizer, Dounce</td><td>VWR</td><td>71000-518</td><td></td></tr></tbody></table>

prevention of heat stress adverse effects in rats by bacillus subtilis strain

This study was designed to evaluate the protective effect of the Bacillus subtilis strain against complications related to heat stress. Thirty-two Sprague-Dawley rats were used in this study. Animals were orally treated twice a day for two days with B. subtilis BSB3 strain or PBS. The next day after the last treatment, each group was divided and two experimental groups (one treated with PBS and one treated with B. subtilis) were placed at 45 oC for 25 min. Two control groups stayed for 25 min at room temperature. All rats were euthanized and different parameters were analyzed in all groups. Adverse effects of heat stress are registered by the decrease of villi height and total mucosal thickness in the intestinal epithelium; translocation of bacteria from the lumen; increased vesiculation of erythrocytes and elevation of the lipopolysaccharides (LPS) level in the blood. The protective efficacy of treatment is evaluated by prevention of these side effects. The protocol was set up for the oral treatment of rats with bacteria for prevention of heat stress complications, but this protocol can be modified and used for other routes of administration and for analysis of different compounds.

The mean body temperature of animals before and immediately after heat stress was 36.7 &#177; 0.07 oC and 40.3 &#177; 0.17 oC, respectively (P &#60; 0.05). Exposure of rats to heat (group 3) resulted in significant inhibition of villi height and total mucosal thickness (Figures 2, 3). Oral administration of BSB3 strain before stress protected intestine from the harmful effect of heat.
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Watch this Scientific Journal Video about Prevention of Heat Stress Adverse Effects in Rats by Bacillus subtilis Strain at JoVE.com

Prevention of Heat Stress Adverse Effects in Rats by Bacillus subtilis Strain

We described a protocol for prevention of heat stress effects in rats by oral pre-treatment with beneficial bacteria. This protocol can be modified and used for various routes of administration and for analysis of different compounds.

Prevention of Heat Stress Adverse Effects in Rats by Bacillus subtilis Strain

This study was designed to evaluate the protective effect of the Bacillus subtilis strain against complications related to heat stress. Thirty-two ...

prevention-heat-stress-adverse-effects-rats-bacillus-subtilis

Research

JoVE Journal

Immunology and Infection

7.5K Views.  Auburn University. We described a protocol for prevention of heat stress effects in rats by oral pre-treatment with beneficial bacteria. This protocol can be modified and used for various routes of administration and for analysis of different compounds.

Video: Prevention of Heat Stress Adverse Effects in Rats by Bacillus subtilis Strain

A Rat Methyl-Seq Platform to Identify Epigenetic Changes Associated with Stress Exposure

As genomes of a wider variety of animals become available, there is an increasing need for tools that can capture dynamic epigenetic changes in these animal models. The rat is one particular model animal where an epigenetic tool can complement many pharmacological and behavioral studies to provide insightful mechanistic information. To this end, we adapted the SureSelect Target Capture System (referred to as Methyl-Seq) for the rat, which can assess DNA methylation levels across the rat genome. The rat design targeted promoters, CpG islands, island shores, and GC-rich regions from all RefSeq genes. 
To implement the platform on a rat experiment, male Sprague Dawley rats were exposed to chronic variable stress for 3 weeks, after which blood samples were collected for genomic DNA extraction. Methyl-Seq libraries were constructed from the rat DNA samples by shearing, adapter ligation, target enrichment, bisulfite conversion, and multiplexing. Libraries were sequenced on a next-generation sequencing platform and the sequenced reads were analyzed to identify DMRs between DNA of stressed and unstressed rats. Top candidate DMRs were independently validated by bisulfite pyrosequencing to confirm the robustness of the platform.
Results demonstrate that the rat Methyl-Seq platform is a useful epigenetic tool that can capture methylation changes induced by exposure to stress.

Here, we describe the protocol and implementation of Methyl-Seq, an epigenomic platform, using a rat model to identify epigenetic changes associated with chronic stress exposure. Results demonstrate that the rat Methyl-Seq platform is capable of detecting methylation differences that arise from stress exposure in rats.

As genomes of a wider variety of animals become available, there is an increasing need for tools that can capture dynamic epigenetic changes in these ...

Biochemistry

Standardized Methods for Measuring Induction of the Heat Shock Response in Caenorhabditis elegans

The heat shock response (HSR) is a cellular stress response induced by cytosolic protein misfolding that functions to restore protein folding homeostasis, or proteostasis. Caenorhabditis elegans occupies a unique and powerful niche for HSR research because the HSR can be assessed at the molecular, cellular, and organismal levels. Therefore, changes at the molecular level can be visualized at the cellular level and their impacts on physiology can be quantitated at the organismal level. While assays for measuring the HSR are straightforward, variations in the timing, temperature, and methodology described in the literature make it challenging to compare results across studies. Furthermore, these issues act as a barrier for anyone seeking to incorporate HSR analysis into their research. Here, a series of protocols is&#160;presented for measuring induction of the HSR in a robust and reproducible manner with RT-qPCR, fluorescent reporters, and an organismal thermorecovery assay. Additionally, we show that a widely used thermotolerance assay is not dependent on the well-established master regulator of the HSR, HSF-1, and therefore should not be used for HSR research. Finally, variations in these assays found in the literature are discussed and best practices are proposed to help standardize results across the field, ultimately facilitating neurodegenerative disease, aging, and HSR research.

Standardized Methods for Measuring Induction of the Heat Shock Response in Caenorhabditis elegans

Here, standardized protocols are presented to assess induction of the heat shock response (HSR) in Caenorhabditis elegans using RT-qPCR at the molecular level, fluorescent reporters at the cellular level, and thermorecovery at the organismal level.

The heat shock response (HSR) is a cellular stress response induced by cytosolic protein misfolding that functions to restore protein folding homeostasis, ...

Environment

Isolation, Purification, and Identification of Bacitracin-producing Bacillus licheniformis from Fresh Feces of Healthy Pigs

Bacillus licheniformis and bacitracin have a huge application market and value in the fields of medicine, chemistry, aquaculture, agricultural, and sideline products. Therefore, the selection of B. licheniformis with high production of bacitracin is of great importance. In this experimental protocol, Bacillus with a high yield of bacitracin was isolated, purified, and identified from the fresh feces of healthy pigs. The inhibitory effect of secondary metabolite bacitracin on Micrococcus luteus was also tested. Thin-layer chromatography and high-performance liquid chromatography were used for the qualitative and quantitative detection of bacitracin. The physiological and biochemical characteristics of B. licheniformis were determined by relevant kits. The phylogenetic relationships of B. licheniformis were determined and constructed using gene sequence detection. This protocol describes and introduces the standard isolation, purification, and identification process of B. licheniformis from animal fresh feces from multiple perspectives, providing a method for the large-scale utilization of B. licheniformis and bacitracin in factories.

Isolation, Purification, and Identification of Bacitracin-producing Bacillus licheniformis from Fresh Feces of Healthy Pigs

This protocol provides a complete and comprehensive description of the detailed process for the isolation, purification, and identification of bacitracin-producing Bacillus licheniformis from healthy pig feces.

Bacillus licheniformis and bacitracin have a huge application market and value in the fields of medicine, chemistry, aquaculture, agricultural, and ...

Bioengineering

Short-Duration Hypothermia Induction in Rats using Models for Studies examining Clinical Relevance and Mechanisms

Therapeutic hypothermia (TH) is a powerful neuroprotective strategy that has provided robust evidence for neuroprotection in pre-clinical studies of neurological disorders. Despite strong pre-clinical evidence, TH has not shown efficacy in clinical trials of most neurological disorders. The only successful trials employing therapeutic hypothermia were related to cardiac arrest in adults and hypoxic ischemic injury in neonates. Further investigations into the parameters of its use, and study design comparisons between pre-clinical and clinical studies, are warranted. This article demonstrates two methods of short-duration hypothermia induction. The first method allows for rapid hypothermia induction in rats using ethanol spray and fans. This method works by cooling the skin, which has been less commonly used in clinical trials and may have different physiological effects. Cooling is much more rapid with this technique than is achievable in human patients due to differences in surface area to volume ratio. Along with this, a second method is also presented, which allows for a clinically achievable cooling rate for short-duration hypothermia. This method is easy to implement, reproducible and does not require active skin cooling.

This article describes two methods of whole-body short-duration hypothermia induction in rats. The first, rapid induction method, employs active cooling using fans and ethanol spray for a rapid decrease in temperature. The second method is a gradual cooling method. This is achieved using the combination of isoflurane anesthesia and the reduction of temperature settings on the homeothermic heat mat. This results in a gradual decrease in core body temperature without the use of any external cooling devices.&#160;

Therapeutic hypothermia (TH) is a powerful neuroprotective strategy that has provided robust evidence for neuroprotection in pre-clinical studies of ...

Medicine

A Preclinical Model of Exertional Heat Stroke in Mice

Heat stroke is the most severe manifestation of heat-related illnesses. Classic heat stroke (CHS), also known as passive heat stroke, occurs at rest, whereas exertional heat stroke (EHS) occurs during physical activity. EHS differs from CHS in etiology, clinical presentation, and sequelae of multi-organ dysfunction. Until recently, only models of CHS have been well established. This protocol aims to provide guidelines for a refined preclinical mouse model of EHS that is free from major limiting factors such as the use of anesthesia, restraint, rectal probes, or electric shock. Male and female C57Bl/6 mice, instrumented with core temperature (Tc) telemetric probes were utilized in this model. For familiarization with the running mode, mice undergo 3 weeks of training using both voluntary and forced running wheels. Thereafter, mice run on a forced wheel inside a climatic chamber set at 37.5 &#176;C and 40%-50% relative humidity (RH) until displaying symptom limitation (e.g., loss of consciousness) at Tc of 42.1-42.5 &#176;C, although suitable results can be obtained at chamber temperatures between 34.5-39.5 &#176;C and humidity between 30%-90%. Depending on the desired severity, mice are removed from the chamber immediately for recovery in ambient temperature or remain in the heated chamber for a longer duration, inducing a more severe exposure and a higher incidence of mortality. Results are compared with sham-matched exercise controls (EXC) and/or na&#239;ve controls (NC). The model mirrors many of the pathophysiological outcomes observed in human EHS, including loss of consciousness, severe hyperthermia, multi-organ damage as well as inflammatory cytokine release, and acute phase responses of the immune system. This model is ideal for hypothesis-driven research to test preventative and therapeutic strategies that may delay the onset of EHS or reduce the multi-organ damage that characterizes this manifestation.

The protocol describes the development of a standardized, repeatable, preclinical model of exertional heat stroke (EHS) in mice free from adverse external stimuli such as electric shock. The model provides a platform for mechanistic, preventative, and therapeutic studies.

Heat stroke is the most severe manifestation of heat-related illnesses. Classic heat stroke (CHS), also known as passive heat stroke, occurs at rest, ...

Investigating the Detrimental Effects of Low Pressure Plasma Sterilization on the Survival of Bacillus subtilis Spores Using Live Cell Microscopy

Plasma sterilization is a promising alternative to conventional sterilization methods for industrial, clinical, and spaceflight purposes. Low pressure plasma (LPP) discharges contain a broad spectrum of active species, which lead to rapid microbial inactivation. To study the efficiency and mechanisms of sterilization by LPP, we use spores of the test organism Bacillus subtilis because of their extraordinary resistance against conventional sterilization procedures. We describe the production of B. subtilis spore monolayers, the sterilization process by low pressure plasma in a double inductively coupled plasma reactor, the characterization of spore morphology using scanning electron microscopy (SEM), and the analysis of germination and outgrowth of spores by live cell microscopy. A major target of plasma species is genomic material (DNA) and repair of plasma-induced DNA lesions upon spore revival is crucial for survival of the organism. Here, we study the germination capacity of spores and the role of DNA repair during spore germination and outgrowth after treatment with LPP by tracking fluorescently-labelled DNA repair proteins (RecA) with time-resolved confocal fluorescence microscopy. Treated and untreated spore monolayers are activated for germination and visualized with an inverted confocal live cell microscope over time to follow the reaction of individual spores. Our observations reveal that the fraction of germinating and outgrowing spores is dependent on the duration of LPP-treatment reaching a minimum after 120 s. RecA-YFP (yellow fluorescence protein) fluorescence was detected only in few spores and developed in all outgrowing cells with a slight elevation in LPP-treated spores. Moreover, some of the vegetative bacteria derived from LPP-treated spores showed an increase in cytoplasm and tended to lyse. The described methods for analysis of individual spores could be exemplary for the study of other aspects of spore germination and outgrowth.

Investigating the Detrimental Effects of Low Pressure Plasma Sterilization on the Survival of Bacillus subtilis Spores Using Live Cell Microscopy

This protocol illustrates the important consecutive steps required to assess the relevance of monitoring vitality parameter and DNA repair processes in reviving Bacillus subtilis spores after treatment with low pressure plasma by tracking fluorescence-labelled DNA repair proteins via time-resolved confocal microscopy and scanning electron microscopy.

Plasma sterilization is a promising alternative to conventional sterilization methods for industrial, clinical, and spaceflight purposes. Low pressure ...

Biology

Establishing and Validating a Chronic Unpredictable Mild Stress Rat Model

Chronic Unpredictable Mild Stress in Rats based on the Mongolian medicine

Depression is a prevalent affective disorder and constitutes a leading cause of global disability. The limitations of current pharmacological interventions contribute to the substantial health burden attributed to this condition. There is a pressing need for a deeper understanding of the underlying mechanisms of depression, making pre-clinical models with translational potential highly valuable. Mongolian medicine, a subset of traditional medicine, posits that disease occurrence is closely tied to the equilibrium of wind, bile, and Phlegm. In this study, we introduce a protocol for the chronic unpredictable mild stress (CUMS) method in rats. Within this framework, rats are subjected to a series of fluctuating, mild stressors to induce a depression-like phenotype, mimicking the pathogenesis of human depression. Behavioral assays employed in this protocol include the sucrose preference test (SPT), indicative of anhedonia-a core symptom of depression; the open field test (OFT), which measures anxiety levels; and the Morris water maze test (MWM), which evaluates spatial memory and learning abilities. The CUMS method demonstrates the capability to induce anhedonia and to cause long-term behavioral deficits. Furthermore, this protocol is more aligned with Mongolian medical theory than other animal models designed to elicit depression-like behavior. The development of this animal model and subsequent research provide a robust foundation for future innovative studies in the realm of Mongolian medicine.

Author Spotlight: Establishing a Rodent Model for Investigating Depression Factors in Traditional Mongolian Medicine

This protocol outlines a chronic unpredictable mild stress (CUMS) model for depression based on Mongolian medical theory, along with methods for validating behavioral tests.

Depression is a prevalent affective disorder and constitutes a leading cause of global disability. The limitations of current pharmacological ...

Measurements of Physiological Stress Responses in C. Elegans

Organisms are often exposed to fluctuating environments and changes in intracellular homeostasis, which can have detrimental effects on their proteome and physiology. Thus, organisms have evolved targeted and specific stress responses dedicated to repair damage and maintain homeostasis. These mechanisms include the unfolded protein response of the endoplasmic reticulum (UPRER), the unfolded protein response of the mitochondria (UPRMT), the heat shock response (HSR), and the oxidative stress response (OxSR). The protocols presented here describe methods to detect and characterize the activation of these pathways and their physiological consequences in the nematode, C. elegans. First, the use of pathway-specific fluorescent transcriptional reporters is described for rapid cellular characterization, drug screening, or large-scale genetic screening (e.g., RNAi or mutant libraries). In addition, complementary, robust physiological assays are described, which can be used to directly assess sensitivity of animals to specific stressors, serving as functional validation of the transcriptional reporters. Together, these methods allow for rapid characterization of the cellular and physiological effects of internal and external proteotoxic perturbations.

Measurements of Physiological Stress Responses in C. Elegans

Here, we characterize cellular proteotoxic stress responses in the nematode C. elegans by measuring the activation of fluorescent transcriptional reporters and assaying sensitivity to physiological stress.

Organisms are often exposed to fluctuating environments and changes in intracellular homeostasis, which can have detrimental effects on their proteome and ...

Investigating the Alleviating Effects of Bacillus cereus Administration on Colitis through Gut Microbiota Modulation

Gut microbiota dysbiosis is thought to exert a role in the progression of colitis. However, the precise standards for probiotic administration in alleviating colitis remain undefined. Most analysis methods rely on limited diversity and abundance of gut microorganisms. Therefore, observational studies cannot establish causation. In this study, we applied antibiotic-induced pseudo-germ-free mice to investigate the role of gut microbiota in regulating the probiotic effects of Bacillus&#160;cereus (B. cereus)&#160;on dextran sulfate sodium (DSS)-induced colitis in mice. This process allows for evaluating the bidirectional regulating effect of B. cereus&#160;supplementation on health and provides stable and reproducible results. Here, the detailed protocols for B. cereus cultivation, gavage operation, stool collection, and antibiotic clearance treatment on colitis mice are provided. The optimization methods are also applicable for other chronic inflammatory-associated disorders. The results showed that B. cereus administration decreased body weight loss, colon length shortening, disease activity index, and histopathological scores. However, treatment with antibiotics suppressed the positive effect of B. cereus on colitis. These results indicate that gut microbiota are needed for the alleviating effects of B. cereus on colitis. Therefore, exploring the beneficial effects of probiotics in this research is a promising approach for developing novel treatment strategies for alleviating the symptoms of chronic inflammatory-associated disorders.

Investigating the Alleviating Effects of Bacillus cereus Administration on Colitis through Gut Microbiota Modulation

Here, we present a protocol to establish the antibiotic-induced pseudo-germ-free dextran sulfate sodium-induced colitis mouse model to investigate the role of gut microbiota in regulating the positive effects of Bacillus cereus on colitis.

Gut microbiota dysbiosis is thought to exert a role in the progression of colitis. However, the precise standards for probiotic administration in ...

High-Throughput Screening of Microbial Isolates with Impact on Caenorhabditis elegans Health

With its small size, short lifespan, and easy genetics, Caenorhabditis elegans offers a convenient platform to study the impact of microbial isolates on host physiology. It also fluoresces in blue when dying, providing a convenient means of pinpointing death. This property has been exploited to develop high-throughput label-free C. elegans survival assays (LFASS). These involve time-lapse fluorescence recording of worm populations set in multiwell plates, from which population median time of death can be derived. The present study adopts the LFASS approach to screen multiple microbial isolates at once for the effects on C. elegans susceptibility to severe heat and oxidative stresses. Such microbial screening pipeline, which can notably be used to prescreen probiotics, using severe stress resistance as a proxy for host health is reported here. The protocol describes how to grow both C. elegans gut microbiota isolate collections and synchronous worm populations in multiwell arrays before combining them for the assays. The example provided covers the testing of 47 bacterial isolates and one control strain on two worm strains, in two stress assays in parallel. However, the approach pipeline is readily scalable and applicable to the screening of many other modalities. Thus, it provides a versatile setup to rapidly survey a multiparametric landscape of biological and biochemical conditions that impact C. elegans health.

High-Throughput Screening of Microbial Isolates with Impact on Caenorhabditis elegans Health

Gut microbes may positively or negatively impact the health of their host via specific or conserved mechanisms. Caenorhabditis elegans is a convenient platform to screen for such microbes. The present protocol describes high-throughput screening of 48 bacterial isolates for impact on nematode stress resistance, used as a proxy for worm health.

With its small size, short lifespan, and easy genetics, Caenorhabditis elegans offers a convenient platform to study the impact of microbial isolates on ...

Prevention of Heat Stress Adverse Effects in Rats by Bacillus subtilis Strain

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