We are grateful to Mr. Akira Murakami of the Department of Applied Biosciences, Toyo University, and Mr. Koudai Taniguchi of the Gunma Agricultural Technology Center for their technical assistance. We are also grateful to Professor Shosaku Kashiwada and Dr. Uma Maheswari Rajagopalan, Toyo University for their suggestions. This study was supported in part by the Research Center for Life and Environmental Sciences, Toyo University.

Note: Ipecac (C. ipecacuanha) was used in this study because it facilitates the analysis of endogenous phytohormones.
1. Growth Conditions to Induce Adventitious Shoots of Ipecac
<ol>
	<li>Prepare phytohormone-free B5 medium adjusted to pH 5.710, and add 0.2% gellan gum. Sterilize by autoclaving.</li>
	<li>Pour 25 mL of the autoclaved medium into a sterile Petri dish (90 mm &#215; 20 mm).</li>
	<li>Cut 8-mm internodal segments of ipecac plantlets using a surgical scalpel with a blade No. 22 on a sterile acrylic plate, and place on the medium (Figure 1).</li>
	<li>Culture on phytohormone-free B5 medium at 24 &#176;C under 15 &#181;mol m&#8722;2 s&#8722;1 of light in a 14-h light/10-h dark cycle for 5 weeks.</li>
	<li>Identify regions I (apical) to IV (basal) in each segment (Figure 1B). Count the number of adventitious shoots &#62; 0.3 mm length in each region under a microscope once a week.</li>
</ol>
2. Extraction and Purification of Phytohormones
<ol>
	<li>Put a 5-mm zirconia bead in each of the four 2-mL sample tubes.</li>
	<li>Cut the segments into regions I to IV (each 2 mm in length) using a surgical scalpel on a sterile acrylic plate.</li>
	<li>Collect eight segments of each region in separate sample tubes (10-30 mg fresh weight).</li>
	<li>Weigh, and then freeze the samples in liquid nitrogen.</li>
	<li>Crush the frozen samples using a bead-based homogenizer.</li>
	<li>Suspend the crushed samples in 1 mL acetonitrile containing 500 pg of each internal standard of auxin and CKs (d5-IAA, d5-tZ, d5-tZR, d6-iP, d6-iPR) using a vortex mixer.</li>
	<li>Hold at 4 &#176;C for 1 h, then centrifuge at 3,500 &#215; g for 5 min at room temperature.</li>
	<li>Wash the pellet in 80% (v/v) acetonitrile containing 1% (v/v) acetic acid. Centrifuge again at 3,500 &#215; g for 5 min at room temperature. Combine the supernatants (from steps 2.7 and 2.8) in a disposable glass tube.</li>
	<li>Add 600 &#181;L water containing 1% (v/v) acetic acid to each combined supernatant, and evaporate the acetonitrile using a vacuum concentrator.</li>
	<li>Equilibrate hydrophilic-lipophilic-balanced (HLB) column cartridges by applying 1 mL each of acetonitrile, methanol, and water containing 1% (v/v) acetic acid.</li>
	<li>Apply one sample solution per equilibrated HLB cartridge.</li>
	<li>Wash the cartridges with 1 mL water containing 1% (v/v) acetic acid.</li>
	<li>Elute all hormones with 2 mL 80% (v/v) acetonitrile containing 1% (v/v) acetic acid in a glass tube.</li>
	<li>Evaporate the acetonitrile in the eluate to obtain extract in water containing 1% (v/v) acetic acid using a vacuum concentrator. 
	NOTE: Do not dry this completely.</li>
	<li>Equilibrate mixed-mode, strong cation-exchange (MCX) column cartridges by applying 1 mL acetonitrile, 1 mL methanol, 0.5 mL 0.1 M HCl, and 1 mL water containing 1% (v/v) acetic acid.</li>
	<li>Apply one sample solution per equilibrated MCX cartridge.</li>
	<li>Wash the cartridges with 1 mL water containing 1% (v/v) acetic acid.</li>
	<li>Elute IAA with 2 mL 30% (v/v) acetonitrile containing 1% (v/v) acetic acid in a glass tube.</li>
	<li>Wash the cartridges with 2 mL 80% (v/v) acetonitrile containing 1% (v/v) acetic acid.</li>
	<li>Wash the cartridges with 2 mL water and 1 mL water containing 5% aqueous ammonia.</li>
	<li>Elute the CKs with 2 mL 60% (v/v) acetonitrile containing 5% aqueous ammonia in a glass tube.</li>
	<li>Evaporate the solvent of each hormone fraction using a vacuum concentrator and store at &#8722;30 &#176;C until the LC-MS/MS analysis.</li>
</ol>
3. LC-MS/MS Analysis of IAA and CKs
<ol>
	<li>Dissolve each hormone extract in a tube with 600 &#181;L of methanol and transfer the solution to a screw neck total recovery vial. Evaporate the solvent using a vacuum concentrator.</li>
	<li>Dissolve the IAA fraction in 20 &#181;L 30% (v/v) acetonitrile, and the CK fractions in 20 &#181;L water containing 1% (v/v) acetic acid in screw neck total recovery vials.</li>
	<li>Analyze the samples in positive ion mode on a triple-quadrupole MS system equipped with an HPLC system. 
	NOTE: We set the HPLC conditions as listed in Table 1.
	<ol>
		<li>For the IAA elution, use a binary gradient of 5%-50% solvent B over 7 min, then increase by 98% solvent B and hold for 1 min, and then equilibrate for 2 min at 5% solvent B by nest injection.</li>
		<li>For the CK elution, use a binary gradient of 2%-40% solvent B over 5 min, 40%-70% solvent B in 7 min, then increase by 95% solvent B and hold for 1 min, and then equilibrate for 2 min at 2% solvent B by nest injection.</li>
		<li>Set the electrospray ionization (ESI)-MS parameters of ion source as listed in Table 2.</li>
	</ol>
	</li>
	<li>Use the multiple reaction monitoring (MRM) transition for quantification of each analyte listed in Table 3.</li>
	<li>Quantify endogenous IAA and CK levels against a standard curve of the ratio of unlabeled to deuterium-labeled standards.</li>
</ol>

<ol>
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The authors declare that they have no conflicts of interest.

To identify the distribution of phytohormones involved in organogenesis, it is important to use plant materials in which organogenesis can be observed on phytohormone-free medium, because when phytohormones are exogenously applied to explants for inducing shoots or roots, they affect the whole explant, making it difficult to evaluate the inherent plasticity of plants in cell differentiation and organogenesis. Adventitious shoots can be induced on phytohormone-free culture media in other plant species such as Dianthus...

Gottlieb Haberlandt (1854-1945) proposed the concept of &#34;totipotency&#34;, by which plant cells can divide, differentiate, and regenerate whole plants even after their prior differentiation into specific cell types in mature plants1. In tissue culture, whether plant regeneration can be induced or not is determined by the combination and concentration of exogenously applied phytohormones in the growth medium. Skoog and Miller found that adventitious shoots could be induced from tobacco callus on culture medium containing a high ratio of CKs to auxins, whereas adventitious roots could be induced on medium containing a low ratio2. Since that finding, tissue culture has been widely used for the propagation of economically important crops and for the regeneration of transgenic plants3. Adventitious shoots can be induced from tissues other than shoot apical meristem, such as leaves, roots, and internodes. Phytohormone treatment is required for the induction of adventitious shoots in most plant species. However, the optimum concentrations and combinations differ by species and among tissues used as explants. Thus, much effort goes into determining the optimum concentrations and combinations of phytohormones for experiments.
Carapichea ipecacuanha (Brot.) L. Andersson (ipecac) is a medicinal plant that contains alkaloids such as emetine and cephaeline, mainly in the roots4. Root extracts are used as an expectorant, an emetic, and an amoebicide5. Although ipecac grows naturally in the tropical rainforests of Brazil, it is reluctant to set seeds in culture, and the germination rate decreases during seed storage in Japan, with its colder climate6. Instead, it is propagated by tissue culture, in which adventitious shoot formation on internodes is the most efficient method7,8. Interestingly, adventitious shoots can be induced in this species without phytohormone treatment8.
Adventitious shoots are formed on the epidermis in the apical region of internodal segments without callusing, but not in the basal region9. This difference indicates tissue polarity in internodal segments, which is probably under phytohormonal regulation. The ipecac culture system allows a unique opportunity to analyze changes in endogenous phytohormone levels during adventitious shoot formation. Here we introduce our method for the analysis of the endogenous levels of one auxin (indole-3-acetic acid (IAA)) and four CKs (isopentenyl adenine (iP), isopentenyl adenine riboside (iPR), trans-zeatin (tZ), and trans-zeatin riboside (tZR)) in internodal segments through the use of LC-MS/MS.

<table border="0" cellpadding="0" cellspacing="0" style="width:677px;" width="678">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">[2H5]indole-3-acetic acid</td>
			<td style="width:176px;">Olchemlm Ltd</td>
			<td style="width:119px;">031 1531</td>
			<td style="width:167px;">Internal standard for LC-MS/MS</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">[2H5]trans-zeatin</td>
			<td style="width:176px;">Olchemlm Ltd</td>
			<td style="width:119px;">030 0301</td>
			<td>Internal standard for LC-MS/MS</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">[2H5]trans-zeatin riboside</td>
			<td style="width:176px;">Olchemlm Ltd</td>
			<td style="width:119px;">030 0311</td>
			<td>Internal standard for LC-MS/MS</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">[2H6]N6-isopentenyl adenine</td>
			<td style="width:176px;">Olchemlm Ltd</td>
			<td style="width:119px;">030 0161</td>
			<td>Internal standard for LC-MS/MS</td>
		</tr>
		<tr height="41">
			<td height="41" style="height:41px;width:216px;">[2H6]N6-isopentenyl adenosine</td>
			<td style="width:176px;">Olchemlm Ltd</td>
			<td style="width:119px;">030 0171</td>
			<td>Internal standard for LC-MS/MS</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">indole-3-acetic acid</td>
			<td style="width:176px;">Wako</td>
			<td>098 00181</td>
			<td>standard for LC-MS/MS</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">trans-zeatin</td>
			<td style="width:176px;">SIGMA-ALDRICH</td>
			<td style="width:119px;">Z0876 5MG</td>
			<td>standard for LC-MS/MS</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">trans-zeatin riboside</td>
			<td style="width:176px;">Wako</td>
			<td>262 01081</td>
			<td>standard for LC-MS/MS</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">N6-isopentenyl adenine</td>
			<td style="width:176px;">SIGMA-ALDRICH</td>
			<td style="width:119px;">D7674 1G</td>
			<td>standard for LC-MS/MS</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">N6-isopentenyl adenosine</td>
			<td style="width:176px;">ACROS ORGANICS</td>
			<td style="width:119px;">22648 1000</td>
			<td>standard for LC-MS/MS</td>
		</tr>
		<tr height="41">
			<td height="41" style="height:41px;width:216px;">acetonitrile hypergrade for LC-MS LiChrosolv</td>
			<td style="width:176px;">MERCK</td>
			<td style="width:119px;">1.00029.1000</td>
			<td>solvent for LC-MS/MS</td>
		</tr>
		<tr height="41">
			<td height="41" style="height:41px;width:216px;">Water for chromatography LiChrosolv</td>
			<td style="width:176px;">MERCK</td>
			<td style="width:119px;">1.15333.1000</td>
			<td>solvent for LC-MS/MS</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">HPLC</td>
			<td style="width:176px;">SHIMADZU</td>
			<td style="width:119px;">Prominence</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">MS</td>
			<td style="width:176px;">Sciex</td>
			<td style="width:119px;">3200QTRAP</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Oasis HLB 30 mg/1 cc</td>
			<td style="width:176px;">Waters</td>
			<td style="width:119px;">WAT094225</td>
			<td>cartridge column</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Oasis MCX 30 mg/1 cc</td>
			<td style="width:176px;">Waters</td>
			<td style="width:119px;">186000252</td>
			<td>cartridge column</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">screw neck total recovery vial</td>
			<td style="width:176px;">Waters</td>
			<td style="width:119px;">186002805</td>
			<td></td>
		</tr>
		<tr height="61">
			<td height="61" style="height:61px;width:216px;">blue, 12 x 32mm screw neck cap and PTFE/silicone septum</td>
			<td style="width:176px;">Waters</td>
			<td style="width:119px;">186000274</td>
			<td></td>
		</tr>
		<tr height="41">
			<td height="41" style="height:41px;width:216px;">Acquity UPLC BEH C18, 2.1x100 mm</td>
			<td style="width:176px;">Waters</td>
			<td style="width:119px;">186002350</td>
			<td>UPLC column</td>
		</tr>
		<tr height="41">
			<td height="41" style="height:41px;width:216px;">Proshell 120 EC-C18, 2.1x50 mm</td>
			<td style="width:176px;">Agilent</td>
			<td style="width:119px;">699775-902</td>
			<td>UPLC column</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Digital microscope</td>
			<td style="width:176px;">Leica</td>
			<td style="width:119px;">DHS1000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">TissueLyser II</td>
			<td style="width:176px;">QIAGEN</td>
			<td style="width:119px;">85300</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Surgical blade</td>
			<td style="width:176px;">Feather</td>
			<td style="width:119px;">No. 22</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Scalpel handle</td>
			<td style="width:176px;">Feather</td>
			<td style="width:119px;">No. 4</td>
			<td></td>
		</tr>
		<tr height="61">
			<td height="61" style="height:61px;width:216px;">Savant SpeedVac/Refregerated vapor trap</td>
			<td style="width:176px;">Thermo Fisher Scientific</td>
			<td style="width:119px;">SPD111/RVT4104</td>
			<td>vacuum concentrartor</td>
		</tr>
		<tr height="41">
			<td height="41" style="height:41px;width:216px;">Disposable glass tobe (13x100 mm)</td>
			<td style="width:176px;">IWAKI</td>
			<td style="width:119px;">9832-1310</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Sterile petri dish</td>
			<td style="width:176px;">INA OPTICA</td>
			<td style="width:119px;">I-90-20</td>
			<td></td>
		</tr>
	</tbody>
</table>

quantification of endogenous auxin and cytokinin during internode culture of ipecac

Adventitious shoot formation is an important technique for the propagation of economically important crops and for the regeneration of transgenic plants. Phytohormone treatment is required for the induction of adventitious shoots in most species. Whether adventitious shoots can be induced is determined by the balance between auxin and cytokinin (CK) levels. Much effort goes into determining optimum concentrations and combinations of phytohormones in each tissue used as explants and in each plant species. In ipecac, however, adventitious shoots can be induced on internodal segments in culture medium without phytohormone treatment. This allows the inherent plasticity of ipecac for cell differentiation to be evaluated. To induce adventitious shoots in ipecac, we cultured internodal segments at 24 &#176;C under 15 &#181;mol m&#8722;2 s&#8722;1 of light in a 14-h light/10-h dark cycle on phytohormone-free B5 medium solidified with 0.2% gellan gum for 5 weeks. To investigate phytohormone dynamics during adventitious shoot formation, we measured endogenous indole-3-acetic acid and CKs in the segments by liquid chromatography-tandem mass spectrometry LC-MS/MS. This method allows analysis of endogenous indole-3-acetic acid and CKs levels in a simple manner. It can be applied to investigate the dynamics of endogenous auxin and CK during organogenesis in other plant species.

At the 1st week, no adventitious shoots had formed. At the 2nd week, small shoots appeared. At the 3rd and 4th weeks, the number of shoots increased mostly in the apical regions (I and II) (Figure 2A). At the 5th week, the number of shoots was approximately 7 in region I and 5 in region II (Figure 2B). In contrast, only a few shoots were form...

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Quantification of Endogenous Auxin and Cytokinin During Internode Culture of Ipecac

Adventitious shoots can be induced on internodal segments of ipecac without phytohormone treatment. To evaluate phytohormone dynamics during adventitious shoot formation, we measured endogenous auxin and cytokinin in internodal segments by LC-MS/MS.

Adventitious shoot formation is an important technique for the propagation of economically important crops and for the regeneration of transgenic plants. ...

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8.9K Views.  Toyo University. Adventitious shoots can be induced on internodal segments of ipecac without phytohormone treatment. To evaluate phytohormone dynamics during adventitious shoot formation, we measured endogenous auxin and cytokinin in internodal segments by LC-MS/MS.

Video: Quantification of Endogenous Auxin and Cytokinin During Internode Culture of Ipecac

EPA Method 1615. Measurement of Enterovirus and Norovirus Occurrence in Water by Culture and RT-qPCR. I. Collection of Virus Samples

EPA Method 1615 was developed with a goal of providing a standard method for measuring enteroviruses and noroviruses in environmental and drinking waters. The standardized sampling component of the method concentrates viruses that may be present in water by passage of a minimum specified volume of water through an electropositive cartridge filter. The minimum specified volumes for surface and finished/ground water are 300 L and 1,500 L, respectively. A major method limitation is the tendency for the filters to clog before meeting the sample volume requirement. Studies using two different, but equivalent, cartridge filter options showed that filter clogging was a problem with 10% of the samples with one of the filter types compared to 6% with the other filter type. Clogging tends to increase with turbidity, but cannot be predicted based on turbidity measurements only. From a cost standpoint one of the filter options is preferable over the other, but the water quality and experience with the water system to be sampled should be taken into consideration in making filter selections.

EPA Method 1615 uses an electropositive filter to concentrate enteroviruses and noroviruses in environmental and drinking waters. This manuscript describes the procedure for collecting samples for Method 1615 analyses.

EPA Method 1615 was developed with a goal of providing a standard method for measuring enteroviruses and noroviruses in environmental and drinking waters. ...

Quantification of Heavy Metals and Other Inorganic Contaminants on the Productivity of Microalgae

Increasing demand for renewable fuels has researchers investigating the feasibility of alternative feedstocks, such as microalgae. Inherent advantages include high potential yield, use of non-arable land and integration with waste streams. The nutrient requirements of a large-scale microalgae production system will require the coupling of cultivation systems with industrial waste resources, such as carbon dioxide from flue gas and nutrients from wastewater. Inorganic contaminants present in these wastes can potentially lead to bioaccumulation in microalgal biomass negatively impact productivity and limiting end use. This study focuses on the experimental evaluation of the impact and the fate of 14 inorganic contaminants (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Se, Sn, V and Zn) on Nannochloropsis salina growth. Microalgae were cultivated in photobioreactors illuminated at 984 &#181;mol m-2 sec-1 and maintained at pH 7 in a growth media polluted with inorganic contaminants at levels expected based on the composition found in commercial coal flue gas systems. Contaminants present in the biomass and the medium at the end of a 7 day growth period were analytically quantified through cold vapor atomic absorption spectrometry for Hg and through inductively coupled plasma mass spectrometry for As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sb, Se, Sn, V and Zn. Results show N. salina is a sensitive strain to the multi-metal environment with a statistical decrease in biomass yieldwith the introduction of these contaminants. The techniques presented here are adequate for quantifying algal growth and determining the fate of inorganic contaminants.

Integration of microalgal cultivation with industrial flue gas will ultimately introduce heavy metals and other inorganic compounds into the growth media. This study presents a procedure used to determine the end fate and impact of heavy metals and inorganic contaminants on the growth of Nannochloropsis salina grown in photobioreactors.

Increasing demand for renewable fuels has researchers investigating the feasibility of alternative feedstocks, such as microalgae. Inherent advantages ...

Simultaneous DNA-RNA Extraction from Coastal Sediments and Quantification of 16S rRNA Genes and Transcripts by Real-time PCR

Real Time Polymerase Chain Reaction also known as quantitative PCR (q-PCR) is a widely used tool in microbial ecology to quantify gene abundances of taxonomic and functional groups in environmental samples. Used in combination with a reverse transcriptase reaction (RT-q-PCR), it can also be employed to quantify gene transcripts. q-PCR makes use of highly sensitive fluorescent detection chemistries that allow quantification of PCR amplicons during the exponential phase of the reaction. Therefore, the biases associated with &#39;end-point&#39; PCR detected in the plateau phase of the PCR reaction are avoided. A protocol to quantify bacterial 16S rRNA genes and transcripts from coastal sediments via real-time PCR is provided. First, a method for the co-extraction of DNA and RNA from coastal sediments, including the additional steps required for the preparation of DNA-free RNA, is outlined. Second, a step-by-step guide for the quantification of 16S rRNA genes and transcripts from the extracted nucleic acids via q-PCR and RT-q-PCR is outlined. This includes details for the construction of DNA and RNA standard curves. Key considerations for the use of RT-q-PCR assays in microbial ecology are included.

A protocol to quantify bacterial 16S rRNA genes and transcripts from coastal sediments via real-time PCR is provided. The methodology includes the co-extraction of DNA and RNA; preparation of DNA-free RNA; and 16S rRNA gene and transcript quantification via RT-q-PCR, including standard curve construction.

Real Time Polymerase Chain Reaction also known as quantitative PCR (q-PCR) is a widely used tool in microbial ecology to quantify gene abundances of ...

Capturing Flow-weighted Water and Suspended Particulates from Agricultural Canals During Drainage Events

The purpose of this study is to describe the methods used to capture flow-weighted water and suspended particulates from farm canals during drainage discharge events. Farm canals can be enriched by nutrients such as phosphorus (P) that are susceptible to transport. Phosphorus in the form of suspended particulates can significantly contribute to the overall P loads in drainage water. A settling tank experiment was conducted to capture suspended particulates during discrete drainage events. Farm canal discharge water was collected in a series of two 200 L settling tanks over the entire duration of the drainage event, so as to represent a composite subsample of the water being discharged. Imhoff settling cones are ultimately used to settle out the suspended particulates. This is achieved by siphoning water from the settling tanks via the cones. The particulates are then collected for physico-chemical analyses.

Nutrients present in particulate form can contribute significantly to the overall loads in agricultural drainage waters. This study describes a novel method to capture flow-weighted water and suspended particulates from farm canal drainage over the entire duration of the drainage event.

The purpose of this study is to describe the methods used to capture flow-weighted water and suspended particulates from farm canals during drainage ...

The Effect of the Application of Thyme Essential Oil on Microbial Load During Meat Drying

Meat is a high protein meal that is used in the preparation of jerky, a popular food snack, where preservation and safety are important. To assure food safety and to extend the shelf life of meat and meat products, the use of either synthetic or natural preservatives have been applied to control and eliminate foodborne bacteria. A growing interest in the application of natural food additives for meat has increased. Microorganisms, such as Escherichia coli, contaminate meat and meat products, causing foodborne illnesses. Therefore, it is necessary to improve the meat conservation process. However, the use of essential oils when the meat is being dried has not been deeply studied. In this regard, there is an opportunity to increase the value of dried meat and reduce the risk of foodborne illnesses by applying essential oils during the drying process. In this protocol, we present a novel method of applying thyme essential oil (TEO) during meat drying, specifically in vapor form directly in a drying chamber. For evaluation, we use Minimal Inhibitory Concentration (MIC) to detect the number of harmful bacteria in the treated samples compared to raw samples. The preliminary results show that this method is a viable and alternative option to synthetic preservatives and that it significantly reduces microbial load in dried meat.

Microorganisms such as Escherichia coli that contaminate meat products cause foodborne illnesses. The use of essential oils in the meat drying process has not been deeply studied. Here, we present a novel method of applying thyme essential oil to meat during drying to reduce the microbial load in dried meat.

Meat is a high protein meal that is used in the preparation of jerky, a popular food snack, where preservation and safety are important. To assure food ...

Stress Distribution During Cold Compression of Rocks and Mineral Aggregates Using Synchrotron-based X-Ray Diffraction

We report detailed procedures for performing compression experiments on rocks and mineral aggregates within a multi-anvil deformation apparatus (D-DIA) coupled with synchrotron X-radiation. A cube-shaped sample assembly is prepared and compressed, at room temperature, by a set of four X-ray transparent sintered diamond anvils and two tungsten carbide anvils, in the lateral and the vertical planes, respectively. All six anvils are housed within a 250-ton hydraulic press and driven inward simultaneously by two wedged guide blocks. A horizontal energy dispersive X-ray beam is projected through and diffracted by the sample assembly. The beam is commonly in the mode of either white or monochromatic X-ray. In the case of white X-ray, the diffracted X-rays are detected by a solid-state detector array that collects the resulting energy dispersive diffraction pattern. In the case of monochromatic X-ray, the diffracted pattern is recorded using a two-dimensional (2-D) detector, such as an imaging plate or a charge-coupled device (CCD) detector. The 2-D diffraction patterns are analyzed to derive lattice spacings. The elastic strains of the sample are derived from the atomic lattice spacing within grains. The stress is then calculated using the predetermined elastic modulus and the elastic strain. Furthermore, the stress distribution in two-dimensions allow for understanding how stress is distributed in different orientations. In addition, a scintillator in the X-ray path yields a visible light image of the sample environment, which allows for the precise measurement of sample length changes during the experiment, yielding a direct measurement of volume strain on the sample. This type of experiment can quantify the stress distribution within geomaterials, which can ultimately shed light on the mechanism responsible for compaction. Such knowledge has the potential to significantly improve our understanding of key processes in rock mechanics, geotechnical engineering, mineral physics, and material science applications where compactive processes are important.

We report detailed procedures for compression experiments on rocks and mineral aggregates within a multi-anvil deformation apparatus coupled with synchrotron X-radiation. Such experiments allow quantification of the stress distribution within samples, that ultimately sheds light on compaction processes in geomaterials.

We report detailed procedures for performing compression experiments on rocks and mineral aggregates within a multi-anvil deformation apparatus (D-DIA) ...

Chemical Isolation, Quantification, and Separation of Skin Lipids from Reptiles

Reptiles signal to conspecifics using lipids in their skin, primarily to enable mate tracking and assessment. The isolation of these lipids has utility in research focused on evolutionary patterns and mechanisms of chemical communication, in addition to understanding the waterproofing role of lipids in the evolution of terrestrial life. In an applied approach, such skin-based cues have potential use for wildlife managers dealing with invasive species. The main steps for quantifying reptile skin lipids in the protocol presented here include extraction, total lipid determination, and fractionation via column chromatography, the latter process resulting in purified eluates of compounds which can then either be analyzed to assign compound identifications (e.g., gas chromatography-mass spectrometry [GC-MS]) and/or used directly in more refined bioassays. Skin lipids can be extracted from living skin, shed skin, or dead whole animals, using nonpolar organic solvents (e.g., hexane, benzene, toluene). Extraction solubilizes the lipids and, then, the solvent can be evaporated to yield a measurable lipid-only extract. Fractionation involves the separation of the total lipid extract into specific eluates via traditional column chromatography. The total lipid extract is first bound to a substrate-based column (e.g., alumina) and, then, individual eluates (&#34;fractions&#34;) of solvent at specific volumes are passed sequentially through the column to elute sets of compounds from the lipid mixture based on common polarity. The fractions progress in polarity at a standardized sequence by increasing the relative amount of polar solvent (e.g., diethyl ether) in nonpolar solvent. In this manuscript, we describe several methods for extracting skin lipids of reptiles and, then, provide a standard protocol for isolating different sets of compounds based on polarity, using traditional column chromatography. Whole lipid extracts or specific fractions can, then, be used in bioassays to determine any biological activity elicited by the compounds therein.

In reptiles, skin lipids from conspecifics are crucial for sexual signaling, with potential use in invasive species management. Here, we describe protocols for extracting skin lipids from shed skin or whole animals, determining and analyzing the total lipid mass, and separating the lipids using fractionation via column chromatography.

Reptiles signal to conspecifics using lipids in their skin, primarily to enable mate tracking and assessment. The isolation of these lipids has utility in ...

Split Point Analysis and Uncertainty Quantification of Thermal-Optical Organic/Elemental Carbon Measurements

Researchers from myriad fields frequently seek to quantify and classify concentrations of carbonaceous aerosols as organic carbon (OC) or elemental carbon (EC). This is commonly accomplished using thermal-optical OC/EC analyzers (TOAs), which enable measurement via controlled thermal pyrolysis and oxidation under specific temperature protocols and within constrained atmospheres. Several commercial TOAs exist, including a semi-continuous instrument that enables on-line analyses in the field. This instrument employs an in-test calibration procedure that requires relatively frequent calibration. This article details a calibration protocol for this semi-continuous TOA and presents an open-source software tool for data analysis and rigorous Monte Carlo quantification of uncertainties. Notably, the software tool includes novel means to correct for instrument drift and identify and quantify the uncertainty in the OC/EC split point. This is a significant improvement on the uncertainty estimation in the manufacturer&#8217;s software, which ignores split point uncertainty and otherwise uses fixed equations for relative and absolute errors (generally leading to under-estimated uncertainties and often yielding non-physical results as demonstrated in several example data sets). The demonstrated calibration protocol and new software tool enabling accurate quantification of combined uncertainties from calibration, repeatability, and OC/EC split point are shared with the intent of assisting other researchers in achieving better measurements of OC, EC, and total carbon mass in aerosol samples.

This article presents a protocol and software tool for the quantification of uncertainties in the calibration and data analysis of a semi-continuous thermal-optical organic/elemental carbon analyzer.

Researchers from myriad fields frequently seek to quantify and classify concentrations of carbonaceous aerosols as organic carbon (OC) or elemental carbon ...

Processing Embryo, Eggshell, and Fungal Culture for Scanning Electron Microscopy

Although scanning electron microscopy (SEM) is being widely used for the ultra-structural analysis of various biological and non-biological samples, methods involved in processing different biological samples involve unique practices. All conventional practices described in the literature for processing samples still find useful applications, but subtle changes in the sample preparation can alter image quality, as well as, introduce artifacts. Hence, using a unique sample preparation technique specific to the type of tissue analyzed is required to obtain a good quality image with ultrastructural resolution. The focus of this study is to provide the optimal sample preparation protocols for imaging embryos, rigid eggshells, and fungal cultures using SEM. The following optimizations were recommended to yield good results for the three different delicate biological samples studied. Use of milder fixatives like 4% paraformaldehyde or 3% glutaraldehyde followed by dehydration with ethanol series is mandatory. Fungal mycelium on agar blocks obtained by slide cultures yields a better ultrastructural integrity compared to cultures taken directly from agar plates. Chemical drying of embryos with HMDS provides drying without introducing surface tension artifacts compared to critical point drying. HMDS prevents cracking caused by shrinkage as samples are less brittle during drying. However, for fungal culture, critical point drying provides acceptable image quality compared to chemical drying. Eggshells can be imaged with no special preparation steps except for thorough washing and air drying prior to mounting. Preparation methodologies were standardized based on acceptable image quality obtained with each trial.&#160;

Here, we present detailed processing protocols for imaging delicate tissue samples using scanning electron microscopy (SEM). Three different processing methods, namely, hexamethyl disilazana (HMDS) chemical drying, simple air drying, and critical point drying are described for preparing rigid eggshells, embryos at early developmental stages, and fungal cultures respectively.

Although scanning electron microscopy (SEM) is being widely used for the ultra-structural analysis of various biological and non-biological samples, ...

Microalgae Cultivation and Biomass Quantification in a Bench-Scale Photobioreactor with Corrosive Flue Gases

Photobioreactors are illuminated cultivation systems for experiments on phototrophic microorganisms. These systems provide a sterile environment for microalgal cultivation with temperature, pH, and gas composition and flow rate control. At bench-scale, photobioreactors are advantageous to researchers studying microalgal properties, productivity, and growth optimization. At industrial scales, photobioreactors can maintain product purity and improve production efficiency. The video describes the preparation and use of a bench-scale photobioreactor for microalgal cultivation, including the safe use of corrosive gas inputs, and details relevant biomass measurements and biomass productivity calculations. Specifically, the video illustrates microalgal culture storage and preparation for inoculation, photobioreactor assembly and sterilization, biomass concentration measurements, and a logistic model for microalgal biomass productivity with rate calculations including maximum and overall biomass productivities. Additionally, since there is growing interest in experiments to cultivate microalgae using simulated or real waste gas emissions, the video will cover the photobioreactor equipment adaptations necessary to work with corrosive gases and discuss safe sampling in such scenarios.

Bench-scale, axenic cultivation facilitates microalgal characterization and productivity optimization before subsequent process scale-up. Photobioreactors provide the necessary control for reliable and reproducible microalgal experiments and can be adapted to safely cultivate microalgae with the corrosive gases (CO2, SO2, NO2) from municipal or industrial combustion emissions.

Photobioreactors are illuminated cultivation systems for experiments on phototrophic microorganisms. These systems provide a sterile environment for ...