Name: controlled-release of chlorine dioxide in a perforated packaging system to extend the storage life and improve the safety of grape tomatoes
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1. Measurement of Gaseous ClO2 in the Headspace of a Closed Chamber
<ol>
	<li>Obtain the materials: ClO2 pouch (0.5 g of ClO2 slurry (9.5% a.i.) in a polymer film selected for its release rate (total surface area of 6 cm2); the exact components are proprietary), a glass chamber (19.14 L), and a lid with switchable gas inlet and outlet.</li>
	<li>Attach the ClO2 pouch to the lid using double-sided tape.</li>
	<li>Close the chamber by sealing the lid with petroleum ...

<ol>
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J., Chung, K. S., Won, M., Bin Song, ., K, <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+aqueous+chlorine+dioxide+treatment+on+the+microbial+growth+and+qualities+of+strawberries+during+storage.">Effect of aqueous chlorine dioxide treatment on the microbial growth and qualities of strawberries during storage.</a> Food Sci Biotechnol. 16 (6), 1018-1022 (2007).</li><li>Sun, X. X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antimicrobial+activity+of+controlled-release+chlorine+dioxide+gas+on+fresh+blueberries.">Antimicrobial activity of controlled-release chlorine dioxide gas on fresh blueberries.</a> J Food Protect. 77 (7), 1127-1132 (2014).</li><li>Wang, Z., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improving+storability+of+fresh+strawberries+with+controlled+release+chlorine+dioxide+in+perforated+clamshell+packaging.">Improving storability of fresh strawberries with controlled release chlorine dioxide in perforated clamshell packaging.</a> Food Bioprocess Technol. 7 (12), 3516-3524 (2014).</li><li>Narciso, J. A., Ference, C. M., Ritenour, M. A., Widmer, W. 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Chlorine dioxide is an ideal biocide to prevent food decay. However, it is unstable at high concentrations and non-transportable, requiring costly generators or inefficient two-part powder mixing. This study examined the application of a stable, ready-to-use form of chlorine dioxide to reduce food spoilage and the incidence of foodborne illness. In contrast to other chlorine dioxide application technologies currently in use, the commercial ClO2 used here is cost effective, has a long shelf life, and does not r...

A diet rich in fresh fruits and vegetables may help to reduce the risk of many diseases, including coronary heart disease and specific types of cancers1. However, there are a number of foodborne microbial pathogens, such as Escherichia coli, Salmonella enterica, and Listeria monocytogenes, associated with the consumption of fresh fruits and vegetables that can cause illness or even death among consumers who eat contaminated produce2. For example, E. coli O157:H7 outbreaks have been associated with grapes, tomatoes, and strawberries3,4, and hepatitis A outbreaks have been associated with fresh blueberries5. In addition, microbial contamination can cause substantial product loss through postharvest decay6. Alternaria alternata is an important plant pathogenic fungus that is known to cause leaf spots and other diseases in over 380 host species of plants7. It has been shown to be the cause of an Alternaria black spot8, a stem canker disease and a leaf blight of tomatoes9. Therefore, a safe and effective postharvest decontamination treatment is needed to both control foodborne pathogens and to prevent postharvest decay in fresh produce.
Low- and non-residue technologies are new trends for alternative sanitizers. A variety of postharvest fungicides have been used to reduce spoilage organisms and to prevent foodborne illness. Ozone, a strong antimicrobial agent, has been shown to preserve the quality and freshness of strawberries and blueberries10,11. However, ozone may cause oxidation of fruit surface tissue and can result in discoloration and the deterioration of flavor quality12. Chlorine has been used to sanitize fresh produce, such as blueberries and apples13. While effective, chlorine can react with nitrogen-containing compounds or ammonia, resulting in carcinogenic byproducts14, especially when used for the sanitization of fresh fruit15.
Chlorine dioxide (ClO2), an alternative sanitizer, was approved by both China and the US for the postharvest treatment of fruits and vegetables16. ClO2 is a water-soluble oxidizing agent with an oxidation capacity 2.5 times greater than that of free chlorine17. ClO2 is highly effective at low concentrations and with a short contact time18. ClO2 has low toxicity and minimal corrosiveness at the concentrations used for disinfection, and it is recognized as one of the most effective bactericidal and fungicidal agents for use in a variety of settings19,20,21.
Numerous research results have shown that ClO2 can control foodborne pathogens and postharvest decay16. For example, ClO2 gas has been used to inactivate L. monocytogenes, Salmonella, and E. coli O157:H7 and to prevent blueberry and strawberry spoilage22,23. ClO2 gas reduces the risk of microbial contamination while maintaining the attributes of fresh fruit, and it was effective at controlling the postharvest decay of strawberries24. However, it is unstable at high concentrations and non-transportable, historically requiring costly generators on site or inefficient two-part powder mixing.
However, a new ClO2 product with a ready-made, controlled-release formulation (i.e., it does not require a generator or the premixing of ingredients) has been shown to be highly effective at controlling food spoilage organisms and pathogens in preliminary experiments25. It is a safe, cost-effective, non-corrosive, easily transportable, and controlled-release form of ClO2, with no adverse effects on the environment. Previous experiments have demonstrated that this slow-release ClO2 powder wrapped in filtration material and placed in clamshell packaging significantly reduced the decay of fresh blueberries and strawberries, decreased berry water loss, and maintained fruit firmness during postharvest storage25,26. Recently, a controlled-release ClO2 packet was developed by sealing a slurry form of ClO2 in a semipermeable polymer film. The objectives of this work were to: 1) monitor ClO2 gas release properties in both a closed container and in perforated clamshells, 2) investigate the effect of a controlled-release ClO2 pouch enclosed in a container on foodborne pathogens and the decay of grape tomatoes, and 3) evaluate the effects of the controlled-release ClO2 on the storage quality of grape tomatoes.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Curoxin chlorine dioxide pouch</td>
			<td>Worrell Water Technologies</td>
			<td></td>
			<td>Slurry, a.i. 9.5% in sealed permeable polymer film</td>
		</tr>
		<tr>
			<td>Grape tomato</td>
			<td>Santa Sweets, Inc</td>
			<td></td>
			<td>Santa Sweets Authentic&#160;</td>
		</tr>
		<tr>
			<td>ClO2 gas detector</td>
			<td>Analytical Technology, Inc., Collegeville, PA</td>
			<td></td>
			<td>PortaSens II&#160;</td>
		</tr>
		<tr>
			<td>Perforated clamshell</td>
			<td>Packaging Plus LLC, Yakima, WA</td>
			<td></td>
			<td>OSU #1, 1 lb</td>
		</tr>
		<tr>
			<td>Escherichia coli&#160;</td>
			<td></td>
			<td></td>
			<td>Wild Type (WT) from fruit surface</td>
		</tr>
		<tr>
			<td>Alternaria alternata</td>
			<td></td>
			<td></td>
			<td>from fruit surface</td>
		</tr>
		<tr>
			<td>E. coli agar&#160;</td>
			<td>EC Broth, Oxoid, UK</td>
			<td></td>
			<td>EC Broth with 1.5% agar</td>
		</tr>
		<tr>
			<td>Potato dextrose agar&#160;</td>
			<td>BD Difco, Sparks, MD</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Levine eosin methylene blue agar</td>
			<td>BD Difco, Sparks, MD</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Trigger spray bottle&#160;</td>
			<td>Impact Products, LLC., Toledo, OH</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sterilized sampling bag&#160;</td>
			<td>Fisherbrand, Fisher Scientific, Pittsburgh, PA</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Orbit shaker&#160;</td>
			<td>New Brunswick Scientific, New Brunswick, NJ</td>
			<td></td>
			<td>Innova 2100</td>
		</tr>
		<tr>
			<td>IUL Instruments Neutec Eddy jet spiral plater inoculation plating system</td>
			<td>Neutec Group Inc., Farmingdale, NY</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>EZ micro optical plate reader&#160;</td>
			<td>Synoptics, Ltd., Cambridge, UK</td>
			<td></td>
			<td>ProtoCOL</td>
		</tr>
		<tr>
			<td>Fruit firmness tester&#160;</td>
			<td>Bioworks Inc, Wamego, KS</td>
			<td></td>
			<td>FirmTech 2&#160;</td>
		</tr>
		<tr>
			<td>Tinytag temperature and RH data logger</td>
			<td>Gemini Data Loggers, West Sussex, UK</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>McFarland equivalence turbidity standard</td>
			<td>Fisherbrand, Fisher Scientific, Pittsburgh, PA</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

controlled-release of chlorine dioxide in a perforated packaging system to extend the storage life and improve the safety of grape tomatoes

A controlled-release chlorine dioxide (ClO2) pouch was developed by sealing a slurry form of ClO2 into semipermeable polymer film; the release properties of the pouch were monitored in containers with or without fruit. The pouch was affixed to the inside of a perforated clamshell containing grape tomatoes, and the effect on microbial population, firmness, and weight loss was evaluated during a 14 day storage period at 20 &#176;C. Within 3 days, the ClO2 concentration in the clamshells reached 3.5 ppm and remained constant until day 10. Thereafter, it decreased to 2 ppm by day 14. The ClO2 pouch exhibited strong antimicrobial activity, reducing Escherichia coli populations by 3.08 log CFU/g and Alternaria alternata populations by 2.85 log CFU/g after 14 days of storage. The ClO2 treatment also reduced softening and weight loss and extended the overall shelf life of the tomatoes. Our results suggest that ClO2 treatment is useful for extending the shelf life and improving the microbial safety of tomatoes during storage without impairing their quality.

The release of ClO2 exhibited a linear pattern over the first few hours. The concentration increased about 2.38 ppm/h over the first 4 h. The release speed slowed after 24 h of incubation, and the ClO2 concentration reached 25.4 ppm. However, the concentration tended to be stable after 24 h of incubation (Figure 1).
The headspace ClO2 concentration in the clamshell with grape tom...

Watch this Scientific Journal Video about Controlled-release of Chlorine Dioxide in a Perforated Packaging System to Extend the Storage Life and Improve the Safety of Grape Tomatoes at JoVE.com

Controlled-release of Chlorine Dioxide in a Perforated Packaging System to Extend the Storage Life and Improve the Safety of Grape Tomatoes

Here, we describe a protocol for the application of a novel, slow-release ClO2 product that reduces spoilage and extends the shelf life of fresh fruit. The slow-release ClO2 product was added to standard commercial grape tomato packaging and tested against Escherichia coli and Alternaria alternata.

A controlled-release chlorine dioxide (ClO2) pouch was developed by sealing a slurry form of ClO2 into semipermeable polymer film; the release properties ...

The overall goal of this experiment is to use a novel controlled release chlorine dioxide product to reduce the risk of food borne illness and food spoilage, and extend the shelf life of fresh fruit. This method can help answer key questions in the agricultural post harvest field about the preservation of fresh fruits and vegetables. The main advantage of this technique is that the release dosage and the chlorine dioxide treatment duration can be controlled throughout the entire storage and handling of the packaged produce.Though this method can provide insight into the controlled release of antimicrobial agents for produce preservation, it can also be applied to other systems such as water sanitization and the deodorization. Before beginning the procedure, attach the chlorine dioxide pouch to the lid of the glass chamber with double sided tape, and seal the chamber with petroleum jelly. Connect the inlet and outlet of a chlorine dioxide gas detector to the chamber, and switch on the inlet and outlet gas flow.Then, measure the chlorine dioxide concentration in the chamber at the indicated time points, and monitor the temperature and relative humidity with temperature and relative humidity data loggers. Next, revive the E.coli by thawing the frozen bacterial stock, and plate the suspension on E.coli agar for a 24 hour incubation at 35 degrees Celsius. The next day, reculture the organisms on a new plate for a 24 hour, 35 degree Celsius incubation.Then, streak a colony onto a Levine Eosin-Methylene Blue Agar plate for another 24 hours at 35 degrees Celsius. Cultures that turn a reflective metallic green are positive for E.coli. Scrape the identified E.coli cells from their agar plate into 50 milliliters of sterile distilled water until the estimated concentration reaches nine log CFU per milliliter as compared to McFarland equivalence turbidity standards, and then pour the 50 milliliters of bacteria into 1950 milliliters of sterile water containing 0.1%Tween 20 to the bacteria to obtain a final inoculum volume of two liters.For A.alternata, culture the fungi on potato dextrose agar at 25 degrees Celsius until spores appear, and prepare a two liters volume sample inoculum as just demonstrated. When the inoculum is ready, place seven kilograms of tomatoes into a 10 liter stainless steel pan that is completely enclosed within an autoclavable bag. Move the bag and pan into a safety hood, and use a trigger sprayer to apply the experimental inoculum solution of interest, while gently stirring the fruits with a gloved hand.After five minutes, place the tomatoes in a single layer, on sterilized foils for two hours. When the fruits are dry, transfer 200 grams of tomatoes into 24 individual one pound perforated clam shells. Carefully fold the contaminated foils, and place them and the gloves into the pan for autoclave sterilization.Now, attach chlorine dioxide pouches to the lids of half of the clam shells, and weigh each whole clam shell. Store all of the clam shells at 20 degrees Celsius for 14 days. Then at the appropriate experimental time points, insert the inlet and outlet tubing of the chlorine dioxide gas detector into the center of the clam shells with a two centimeters distance between the two ends, and obtain the chlorine dioxide measurement.To calculate the weight loss in comparison to the initial weight, weigh the whole clam shell with the fruit. For measurement of the microbial population present on the fruit surface at each time point, agitate five fruits from each replicate with 99 milliliters of sterile phosphate buffered saline in a sterilized sampling bag at 100 revolutions per minute for one hour on an orbital shaker. At the end of the agitation, use a spiral plater to seed 50 microliters serial dilutions of the buffer wash on to the appropriate agar plate for the appropriate incubation period, and use an optical plate reader to measure the microbial colony count.To measure the fruit firmness, use a fruit firmness tester according to the manufacturer's instructions to analyze 20 fruits from each replicate, remembering to sanitize the equipment after use, expressing the results as the pressure force required to compress the fruit by one millimeter. Then, analyze the data using analysis of variance and determine the mean separation by Duncan's multiple range test. Chlorine dioxide release initially exhibits a linear pattern with an increase in concentration of about 2.38 parts per million per hour over the first four hours.The release speed slows over the next 20 hours to a chlorine dioxide concentration of 25.4 parts per million, at which point the gas concentration appears to stabilize. The head space chlorine dioxide concentration in a clam shell of grape tomatoes typically measures to be about four parts per million between days three and ten, at which point the gas concentration decreases until it reaches about two parts per million on day 14. The initial bacterial population concentrations on the fruit after inoculation, are 4.3 log colony forming units per gram for E.coli, and 3.4 log colony forming units per gram for A.alternata, levels which are reduced by 3.08 and 2.85 log colony forming units per gram respectively after 14 days of storage in chlorine dioxide treated clam shells.Further, chlorine dioxide treatment not only maintains the firmness and weight of the fruit compared to control untreated tomatoes, but these effects also appear to be augmented over time. After watching this video, you should have a good understanding of how to utilize this new chlorine dioxide product for preserving and extending the shelf life of fresh produce.

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Research

JoVE Journal

Environment

Automated Gel Size Selection to Improve the Quality of Next-generation Sequencing Libraries Prepared from Environmental Water Samples

Next-generation sequencing of environmental samples can be challenging because of the variable DNA quantity and quality in these samples. High quality DNA libraries are needed for optimal results from next-generation sequencing. Environmental samples such as water may have low quality and quantities of DNA as well as contaminants that co-precipitate with DNA. The mechanical and enzymatic processes involved in extraction and library preparation may further damage the DNA. Gel size selection enables purification and recovery of DNA fragments of a defined size for sequencing applications. Nevertheless, this task is one of the most time-consuming steps in the DNA library preparation workflow. The protocol described here enables complete automation of agarose gel loading, electrophoretic analysis, and recovery of targeted DNA fragments. 
In this study, we describe a high-throughput approach to prepare high quality DNA libraries from freshwater samples that can be applied also to other environmental samples. We used an indirect approach to concentrate bacterial cells from environmental freshwater samples; DNA was extracted using a commercially available DNA extraction kit, and DNA libraries were prepared using a commercial transposon-based protocol. DNA fragments of 500 to 800 bp were gel size selected using Ranger Technology, an automated electrophoresis workstation. Sequencing of the size-selected DNA libraries demonstrated significant improvements to read length and quality of the sequencing reads.

This manuscript describes an automated gel size selection approach for purifying DNA fragments for next-generation sequencing. The Ranger Technology provides complete automation of the entire process of agarose gel loading, electrophoretic analysis, and recovery of targeted DNA fragments allowing for high-throughput and high quality next-generation sequencing libraries.

Next-generation sequencing of environmental samples can be challenging because of the variable DNA quantity and quality in these samples. High quality DNA ...

The Use of an Automated System (GreenFeed) to Monitor Enteric Methane and Carbon Dioxide Emissions from Ruminant Animals

Ruminant animals (domesticated or wild) emit methane (CH4) through enteric fermentation in their digestive tract and from decomposition of manure during storage. These processes are the major sources of greenhouse gas (GHG) emissions from animal production systems. Techniques for measuring enteric CH4 vary from direct measurements (respiration chambers, which are highly accurate, but with limited applicability) to various indirect methods (sniffers, laser technology, which are practical, but with variable accuracy). The sulfur hexafluoride (SF6)&#160;tracer gas method is commonly used to measure enteric CH4 production by animal scientists and more recently, application of an Automated Head-Chamber System (AHCS) (GreenFeed, C-Lock, Inc., Rapid City, SD), which is the focus of this experiment, has been growing. AHCS is an automated system to monitor CH4 and carbon dioxide (CO2) mass fluxes from the breath of ruminant animals. In a typical AHCS operation, small quantities of baiting feed are dispensed to individual animals to lure them to AHCS multiple times daily. As the animal visits AHCS, a fan system pulls air past the animal&#8217;s muzzle into an intake manifold, and through an air collection pipe where continuous airflow rates are measured. A sub-sample of air is pumped out of the pipe into non-dispersive infra-red sensors for continuous measurement of CH4 and CO2 concentrations. Field comparisons of AHCS to respiration chambers or SF6 have demonstrated that AHCS produces repeatable and accurate CH4 emission results, provided that animal visits to AHCS are sufficient so emission estimates are representative of the diurnal rhythm of rumen gas production. Here, we demonstrate the use of AHCS to measure CO2 and CH4 fluxes from dairy cows given a control diet or a diet supplemented with technical-grade cashew nut shell liquid.

The Use of an Automated System GreenFeed to Monitor Enteric Methane and Carbon Dioxide Emissions from Ruminant Animals

Accuracy and precision of the techniques used to measure methane emissions from ruminant animals are critically important for the success of greenhouse gas mitigation efforts. This manuscript describes the principles and operation of an automated system to monitor methane and carbon dioxide mass fluxes from the breath of ruminant animals.

Ruminant animals (domesticated or wild) emit methane (CH4) through enteric fermentation in their digestive tract and from decomposition of manure during ...

Methods of Soil Resampling to Monitor Changes in the Chemical Concentrations of Forest Soils

Recent soils research has shown that important chemical soil characteristics can change in less than a decade, often the result of broad environmental changes. Repeated sampling to monitor these changes in forest soils is a relatively new practice that is not well documented in the literature and has only recently been broadly embraced by the scientific community. The objective of this protocol is therefore to synthesize the latest information on methods of soil resampling in a format that can be used to design and implement a soil monitoring program. Successful monitoring of forest soils requires that a study unit be defined within an area of forested land that can be characterized with replicate sampling locations. A resampling interval of 5 years is recommended, but if monitoring is done to evaluate a specific environmental driver, the rate of change expected in that driver should be taken into consideration. Here, we show that the sampling of the profile can be done by horizon where boundaries can be clearly identified and horizons are sufficiently thick to remove soil without contamination from horizons above or below. Otherwise, sampling can be done by depth interval. Archiving of sample for future reanalysis is a key step in avoiding analytical bias and providing the opportunity for additional analyses as new questions arise.

Repeated soil sampling has recently been shown to be an effective way to monitor forest soil change over years and decades. To support its use, a protocol is presented that synthesizes the latest information on soil resampling methods to aid in the design and implementation of successful soil monitoring programs.

Recent soils research has shown that important chemical soil characteristics can change in less than a decade, often the result of broad environmental ...

A Flow-through Exposure System for Evaluating Suspended Sediments Effects on Aquatic Life

This paper describes the Fish Larvae and Egg Exposure System (FLEES). The flow-through exposure system is used to investigate the effects of suspended sediment on various aquatic species and life stages in the laboratory by using pumps and automating delivery of sediment and water to simulate suspension of sediment. FLEES data are used to develop exposure-response curves between the effects on aquatic organisms and suspended sediment concentrations at the desired exposure duration. The effects data are used to evaluate management practices used to reduce the interactions between aquatic organisms and anthropogenic causes of suspended sediments. The FLEES is capable of generating total suspended solids (TSS) concentrations as low as 30 to as high as 800 mg/L, making this system an ideal choice for evaluating the effects of TSS resulting from many activities including simulating low ambient levels of TSS to evaluating sources of suspended sediments from dredging operations, vessel traffic, freshets, and storms.

A robust and flexible flow-through exposure system designed to maintain sediment in suspension is presented. The system is used to investigate the effects of suspended sediment on various aquatic species and life stages in the laboratory.

This paper describes the Fish Larvae and Egg Exposure System (FLEES). The flow-through exposure system is used to investigate the effects of suspended ...

Measurement of the Rheology of Crude Oil in Equilibrium with CO2 at Reservoir Conditions

A rheometer system to measure the rheology of crude oil in equilibrium with carbon dioxide (CO2) at high temperatures and pressures is described. The system comprises a high-pressure rheometer which is connected to a circulation loop. The rheometer has a rotational flow-through measurement cell with two alternative geometries: coaxial cylinder and double gap. The circulation loop contains a mixer, to bring the crude oil sample into equilibrium with CO2, and a gear pump that transports the mixture from the mixer to the rheometer and recycles it back to the mixer. The CO2 and crude oil are brought to equilibrium by stirring and circulation and the rheology of the saturated mixture is measured by the rheometer. The system is used to measure the rheological properties of Zuata crude oil (and its toluene dilution) in equilibrium with CO2 at elevated pressures up to 220 bar and a temperature of 50 &#176;C. The results show that CO2 addition changes the oil rheology significantly, initially reducing the viscosity as the CO2 pressure is increased and then increasing the viscosity above a threshold pressure. The non-Newtonian response of the crude is also seen to change with the addition of CO2.

Measurement of the Rheology of Crude Oil in Equilibrium with CO2 at Reservoir Conditions

A method for measuring the rheology of crude oil in equilibrium with carbon dioxide at reservoir conditions is presented.

A rheometer system to measure the rheology of crude oil in equilibrium with carbon dioxide (CO2) at high temperatures and pressures is described. The ...

Measuring and Mapping Patterns of Soil Erosion and Deposition Related to Soil Carbonate Concentrations Under Agricultural Management

Spatial patterns of soil erosion and deposition can be inferred from differences in ground elevation mapped at appropriate time increments. Such changes in elevation are related to changes in near-surface soil carbonate (CaCO3) profiles. The objective is to describe a simple conceptual model and detailed protocol for repeatable field and laboratory measurements of these quantities. Here, accurate elevation is measured using a ground-based differential global positioning system (GPS); other data acquisition methods could be applied to the same basic method. Soil samples are collected from prescribed depth intervals and analyzed in the lab using an efficient and precise modified pressure-calcimeter method for quantitative analysis of inorganic carbon concentration. Standard statistical methods are applied to point data, and representative results show significant correlations between changes in soil surface layer CaCO3 and changes in elevation consistent with the conceptual model; CaCO3 generally decreased in depositional areas and increased in erosional areas. Maps are derived from point measurements of elevation and soil CaCO3 to aid analyses. A map of erosional and depositional patterns at the study site, a rain-fed winter wheat field cropped in alternating wheat-fallow strips, shows the interacting effects of water and wind erosion affected by management and topography. Alternative sampling methods and depth intervals are discussed and recommended for future work relating soil erosion and deposition to soil CaCO3.

Spatial patterns of soil erosion and deposition can be inferred from differences in ground elevation mapped at appropriate time increments. Such changes in elevation are related to changes in near-surface soil carbonates. Repeatable methods for field and laboratory measurements of these quantities and data analysis methods are described here.

Spatial patterns of soil erosion and deposition can be inferred from differences in ground elevation mapped at appropriate time increments. Such changes ...

Methodology for Developing Life Tables for Sessile Insects in the Field Using the Whitefly, Bemisia tabaci, in Cotton As a Model System

Life tables provide a means of measuring the schedules of birth and death from populations over time. They also can be used to quantify the sources and rates of mortality in populations, which has a variety of applications in ecology, including agricultural ecosystems. Horizontal, or cohort-based, life tables provide for the most direct and accurate method of quantifying vital population rates because they follow a group of individuals in a population from birth to death. Here, protocols are presented for conducting and analyzing cohort-based life tables in the field that takes advantage of the sessile nature of the immature life stages of a global insect pest, Bemisia tabaci. Individual insects are located on the underside of cotton leaves and are marked by drawing a small circle around the insect with a non-toxic pen. This insect can then be observed repeatedly over time with the aid of hand lenses to measure development from one stage to the next and to identify stage-specific causes of death associated with natural and introduced mortality forces. Analyses explain how to correctly measure multiple mortality forces that act contemporaneously within each stage and how to use such data to provide meaningful population dynamic metrics. The method does not directly account for adult survival and reproduction, which limits inference to dynamics of immature stages. An example is presented that focused on measuring the impact of bottom-up (plant quality) and top-down (natural enemies) effects on the mortality dynamics of B. tabaci in the cotton system.

Methodology for Developing Life Tables for Sessile Insects in the Field Using the Whitefly, Bemisia tabaci, in Cotton As a Model System

Life tables allow quantification of the sources and rates of mortality in insect populations and contribute to understanding, predicting and manipulating population dynamics in agroecosystems. Methods for conducting and analyzing cohort-based life tables in the field for an insect with sessile immature life stages are presented.

Life tables provide a means of measuring the schedules of birth and death from populations over time. They also can be used to quantify the sources and ...

Techniques for Investigating the Anatomy of the Ant Visual System

This article outlines a suite of techniques in light microscopy (LM) and electron microscopy (EM) which can be used to study the internal and external eye anatomy of insects. These include traditional histological techniques optimized for work on ant eyes and adapted to work in concert with other techniques such as transmission electron microscopy (TEM) and scanning electron microscopy (SEM). These techniques, although vastly useful, can be difficult for the novice microscopist, so great emphasis has been placed in this article on troubleshooting and optimization for different specimens. We provide information on imaging techniques for the entire specimen (photo-microscopy and SEM) and discuss their advantages and disadvantages. We highlight the technique used in determining lens diameters for the entire eye and discuss new techniques for improvement. Lastly, we discuss techniques involved in preparing samples for LM and TEM, sectioning, staining, and imaging these samples. We discuss the hurdles that one might come across when preparing samples and how best to navigate around them.

This article outlines a suite of techniques in light and electron microscopy to study the internal and external eye anatomy of insects. These include several traditional techniques optimized for work on ant eyes, detailed troubleshooting, and suggestions for optimization for different specimens and regions of interest.

This article outlines a suite of techniques in light microscopy (LM) and electron microscopy (EM) which can be used to study the internal and external eye ...

A Precise and Autonomous System for the Detection of Insect Emergence Patterns

Existing systems to measure insect emergence patterns have limitations; they are only partially automated and are limited in the maximum number of emerging insects they can detect. In order to obtain precise measurement of insect emergence, it is necessary for systems to be semi-automated and able to measure large numbers of emerging insects. We addressed these issues by designing and building a system that is automated and can measure emergence of up to 1200 insects. We modified the existing &#34;falling-ball&#34; system using Arduino microcontrollers to automate data collection and expand the sample size through multiple data channels. Multiple data channels enable the user to not only increase their sample size, but also allows for multiple treatments to be run simultaneously in a single experiment. Furthermore, we created an R script to automatically visualize the data as a bubble plot, while also calculating the median day and time of emergence. The current system was designed using 3D printing so the user can modify the system to be adjusted for different species of insects. The goal of this protocol is to investigate important questions in chronobiology and stress physiology, using this precise and automated system to measure insect emergence patterns.

Measurement of insect emergence patterns requires precision. Existing systems are only semi-automated and sample size is limited. We addressed these issues by designing a system using microcontrollers to precisely measure the time of emergence of large numbers of emerging insects.

Existing systems to measure insect emergence patterns have limitations; they are only partially automated and are limited in the maximum number of ...

Composition and Distribution Analysis of Bioaerosols Under Different Environmental Conditions

Variable microorganisms in particulate matter (PM) under different environmental conditions may have significant impacts on human health. In this study, we described a protocol for multiple analyses of the biological compositions in environmental PM. Five experiments are presented: (1) PM number monitoring by using a laser particle counter; (2) PM collection by using a cyclonic aerosol sampler; (3) PM collection by using a high-volume air sampler with filters; (4) culturable microbes collection by the Andersen six-stage sampler; and (5) detection of biological composition of environmental PM by bacterial 16SrDNA and fungal ITS region sequencing. We selected hazy days and a livestock farm as two typical examples of the application in this protocol. In this study, these two sampling methods, cyclonic aerosol sampler and filter sampler, showed different sampling efficiency. The cyclonic aerosol sampler performed much better in terms of collecting bacteria, while these two methods showed the same efficiency in collecting fungi. Filter samplers can work under low temperature conditions while cyclonic aerosol samplers have a sampling limitation for temperature. A solid impacting sampler, such as an Andersen six-stage sampler, can be used to sample bioaerosols directly into the culture medium, which increases the survival rate of culturable microorganisms. However, this method mainly relies on culture while more than 99% of microbes cannot be cultured. DNA extracted from the culturable bacteria collected by the Andersen six-stage sampler and samples collected by cyclonic aerosol sampler and filter sampler were detected by bacterial 16S rDNA and fungal ITS region sequencing.All the methods above may have wide application in many fields of study, such as environmental monitoring and airborne pathogen detection. From these results, we can conclude that these methods can be used under different conditions and may help other researchers further explore the health impacts of environmental bioaerosols.

Understanding the biological composition of environmental particulate matter is important for the study of its significant impacts on human health and disease spread. Here, we used three types of bioaerosol sampling methods and a biological analysis of airborne microbes to better explore airborne microbial communities under different environmental conditions.

Variable microorganisms in particulate matter (PM) under different environmental conditions may have significant impacts on human health. In this study, ...