Name: a small volume bioassay to assess bacterial/phytoplankton co-culture using water-pulse-amplitude-modulated (water-pam) fluorometry
Uploaded: 2015-03-11T13:00:00
Description: Watch this Scientific Journal Video about A Small Volume Bioassay to Assess Bacterial/Phytoplankton Co-culture Using WATER-Pulse-Amplitude-Modulated WATER-PAM Fluorometry at JoVE.com

This work was supported by Natural Sciences and Engineering Research Council of Canada (grant 402105), Canadian Foundation for Innovation (grant 129087) and Alberta Education and Training (grant AAETRCP-12-026-SEG) to RJC.

1. Calculations for Experimental Setup
<ol>
	<li>Calculate the volume of algal and/or bacterial cultures needed for controls that will be required for the entire experiment by using Equation 1: 
	<img alt="Equation 1" src="/files/ftp_upload/52455/52455equation1.1.jpg" /> 
	Where y equals the number of controls needed per day and z equals the number of days.</li>
	<li>Calculate the volume of algal and/or bacterial cultures that are needed for co-cultures for the experiment by using Equation 2: 
	<img alt=...

<ol>
	<li>Scarratt, M. G., Marchetti, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessing+microbial+responses+to+iron+enrichment+in+the+Subarctic+Northeast+Pacific:+Do+microcosms+reproduce+the+in+situ+condition?.">Assessing microbial responses to iron enrichment in the Subarctic Northeast Pacific: Do microcosms reproduce the in situ condition?.</a> Deep Sea Res Part II Top. Stud. Oceanogr. 53 (20-22), 2182-2200 (2006).</li><li>Bidle, K. D., Haramaty, L., Barcelos E Ramos, J., Falkowski, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Viral+activation+and+recruitment+of+metacaspases+in+the+unicellular+coccolithophore,+Emiliania+huxleyi.">Viral activation and recruitment of metacaspases in the unicellular coccolithophore, Emiliania huxleyi.</a> Proc. Natl. Acad. Sci. U. S. A. 104 (14), 6049-6054 (2007).</li><li>Moore, L. R., Goericke, R., Chisholm, S. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+physiology+of+Synechococcus+and+Prochlorococcus:+influence+of+light+and+temperature+on+growth,+pigments,+fluorescence+and+absorptive.">Comparative physiology of Synechococcus and Prochlorococcus: influence of light and temperature on growth, pigments, fluorescence and absorptive.</a> Mar. Ecol. Prog. Ser. 116, (1995).</li><li>Iglesias-Rodriguez, M. D., Halloran, P. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phytoplankton+calcification+in+a+high-CO2+world.">Phytoplankton calcification in a high-CO2 world.</a> Science. 320 (5874), 336-340 (2008).</li><li>Chen, M., Tang, H., Ma, H., Holland, T. C., Ng, K. Y. S., Salley, S. O. <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+nutrients+on+growth+and+lipid+accumulation+in+the+green+algae+Dunaliella+tertiolecta.">Effect of nutrients on growth and lipid accumulation in the green algae Dunaliella tertiolecta.</a> Bioresour. Technol. 102 (2), 1649-1655 (2011).</li><li>Lv, J. -. M., Cheng, L. -. H., Xu, X. -. H., Zhang, L., Chen, H. -. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enhanced+lipid+production+of+Chlorella+vulgaris+by+adjustment+of+cultivation+conditions.">Enhanced lipid production of Chlorella vulgaris by adjustment of cultivation conditions.</a> Bioresour. Technol. 101 (17), 6797-6804 (2010).</li><li>Geider, R., Graziano, L., McKay, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Responses+of+the+photosynthetic+apparatus+of+Dunaliella+tertiolecta+(Chlorophyceae)+to+nitrogen+and+phosphorus+limitation.">Responses of the photosynthetic apparatus of Dunaliella tertiolecta (Chlorophyceae) to nitrogen and phosphorus limitation.</a> Eur. J. Phycol. 33 (4), 315-332 (1998).</li><li>MacIntyre, H. L., Cullen, J. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Using+Cultures+to+Investigate+the+Physiological+Ecology+of+Microalgae.">Using Cultures to Investigate the Physiological Ecology of Microalgae.</a> Algal Cult. Tech. , 287-326 (2005).</li><li>Blaise, C., Vasseur, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Algal+microplate+toxicity+test.">Algal microplate toxicity test.</a> Small-scale Freshw. Toxic. Investig. Vol. 1 Toxic. Test Methods. , 137-179 (2005).</li><li>Skjelbred, B., Edvardsen, B., Andersen, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+high-throughput+method+for+measuring+growth+and+loss+rates+in+microalgal+cultures.">A high-throughput method for measuring growth and loss rates in microalgal cultures.</a> J. Appl. Phycol. 24, 1589-1599 (2012).</li><li>Nagai, T., Taya, K., Annoh, H., Ishihara, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Application+of+a+fluorometric+microplate+algal+toxicity+assay+for+riverine+periphytic+algal+species.">Application of a fluorometric microplate algal toxicity assay for riverine periphytic algal species.</a> Ecotoxicol. Environ. Saf. 94, 37-44 (2013).</li><li>Seyedsayamdost, M. R., Case, R. J., Kolter, R., Clardy, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Jekyll-and-Hyde+chemistry+of+Phaeobacter+gallaeciensis.">The Jekyll-and-Hyde chemistry of Phaeobacter gallaeciensis.</a> Nat. Chem. 3 (4), 331-335 (2011).</li><li>Schreiber, U., Schliwa, U., Bilger, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Continuous+recording+of+photochemical+and+non-photochemical+chlorophyll+fluorescence+quenching+with+a+new+type+of+modulation+fluorometer.">Continuous recording of photochemical and non-photochemical chlorophyll fluorescence quenching with a new type of modulation fluorometer.</a> Photosynth. Res. 10 (1-2), 51-62 (1986).</li><li>Jones, R. J., Ward, S., Amri, A. Y., Hoegh-Guldber, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Changes+in+quantum+efficiency+of+photosystem+II+of+symbiotic+dinoflagellates+of+corals+after+heat+stress,+and+of+bleached+corals+sampled+after+the+1998+Great+Barrier+Reef+mass+bleaching+event.">Changes in quantum efficiency of photosystem II of symbiotic dinoflagellates of corals after heat stress, and of bleached corals sampled after the 1998 Great Barrier Reef mass bleaching event.</a> Mar. Freshw. Res. 51 (345), 659-668 (1998).</li><li>Beer, S., Larsson, C., Poryan, O., Axelsson, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photosynthetic+rates+of+Ulva+(Chlorophyta)+measured+by+pulse+amplitude+modulated+fluorometry.">Photosynthetic rates of Ulva (Chlorophyta) measured by pulse amplitude modulated fluorometry.</a> Eur. J. Phycol. 35 (1), 69-74 (2000).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> WATER-PAM Chlorophyll Fluorometer. Instrument Description and Information for Users. , (2013).</li><li>Maxwell, K., Johnson, G. M., Heers, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chlorophyll+fluorescence--a+practical+guide.">Chlorophyll fluorescence--a practical guide.</a> J. Exp. Bot. 51 (345), 659-668 (2000).</li><li>Herigstad, B., Hamilton, M., Heersink, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=How+to+optimize+the+drop+plate+method+for+enumerating+bacteria.">How to optimize the drop plate method for enumerating bacteria.</a> J. Microbiol. Methods. 44 (2), 121-129 (2001).</li><li>Kooten, O., Snel, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+use+of+chlorophyll+fluorescence+nomenclature+in+plant+stress+physiology.">The use of chlorophyll fluorescence nomenclature in plant stress physiology.</a> Photosynth. Res. 25 (3), 147-150 (1990).</li><li>Maxwell, K., Johnson, G. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chlorophyll+fluorescence--a+practical+guide.">Chlorophyll fluorescence--a practical guide.</a> J. Exp. Bot. 51 (345), 659-668 (2000).</li><li>Schreiber, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pulse-Amplitude-Modulation+(PAM)+Fluorometry+and+Saturation+Pulse+Method:+An+Overview.">Pulse-Amplitude-Modulation (PAM) Fluorometry and Saturation Pulse Method: An Overview.</a> Chlorophyll a Fluoresc. A Signat. Photosynth. , 279-319 (2004).</li><li>Roh&#225;&#269;ek, K., Bart&#225;k, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Technique+of+the+modulated+chlorophyll+fluorescence:+basic+concepts,+useful+parameters,+and+some+applications.">Technique of the modulated chlorophyll fluorescence: basic concepts, useful parameters, and some applications.</a> Photosynthetica. 37 (3), 339-363 (1999).</li><li>Da Silva, J. M., da Silva, A. B., P&#225;dua, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modulated+chlorophyll+a+fluorescence:+a+tool+for+teaching+photosynthesis.">Modulated chlorophyll a fluorescence: a tool for teaching photosynthesis.</a> J. Biol. Educ. 41 (4), 178-183 (2007).</li><li>Vieira, S., Ribeiro, L., Jesus, B., Cartaxana, P., da Silva, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photosynthesis+assessment+in+microphytobenthos+using+conventional+and+imaging+pulse+amplitude+modulation+fluorometry.">Photosynthesis assessment in microphytobenthos using conventional and imaging pulse amplitude modulation fluorometry.</a> Photochem. Photobiol. 89 (1), 97-102 (2013).</li></ol>

Algal growth in a miniaturized format.
The miniaturization of algal cultures to a 1 ml culture volume in a microtiter plate allows for the replication within an experiment to be increased. It is important to ensure the alga is healthy throughout an experiment; perform a growth curve (Figure 2), using the microtiter plate format to assess various algal media, to ensure the nutritional requirements of the alga are met. Additionally, it may be important to optimize the diurnal cycle...

Phytoplankton physiology has traditionally been studied in meso-scale experiments ranging from 20 ml in conical flasks to 5 L in carboys1&#8211;7. This experimental scale requires subsampling for experimental monitoring, as sacrificing replicate samples for each time point creates an unmanageable experimental setup.
The ability to increase the number of independent experiments while using the same diurnal incubator space by miniaturizing the experimental volume for algal physiology experiments will reduce or eliminate the limitations of subsampling and pseudo-replication from large volumes. A microtiter plate format has been developed for algal bioassays using a 1 ml culture volume for experimentally manipulating algae in variable conditions. This small experimental volume allows for the number of replicates to be increased, increases experimental reproducibility due to a decreased variability between replicate samples and experiments, and allows true replication while maintaining experimental controls (i.e., axenic algal cultures) for 140 days (Figure 2)12.
This microtiter plate format is easily adapted for a variety of experimental questions, such as: does a bacterium have a symbiotic, neutral or pathogenic interaction with its algal host? Is the addition of a compound stimulating or toxic to an alga? These and other questions can be addressed in a rapid high-throughput manner using this new format9&#8211;11.
A 48-well microtiter culture plate allows each 1 ml well to be an independent experimental setup that is sampled at a single time-point. Various parameters can be sampled from this 1 ml volume including, but not limited to: chlorophyll fluorescence and photochemical parameters using WATER-Pulse-Amplitude-Modulated (WATER-PAM) fluorometry (see Materials and Equipment table)13. WATER-PAM fluorometry is a rapid and non-invasive technique that can be used to monitor experiments performed with algae13. It allows measurement of photosynthetic efficiency and PSII health from a small culture volume (150 - 300 &#956;l of culture diluted in medium to a 2 - 4 ml volume for WATER-PAM)14,15. In addition to WATER-PAM fluorometry, this setup can be used to measure a variety of other parameters including, but not limited to: microscopy to visualize the bacteria attached to algal cells and changes in the algal cell morphology; bacterial colony forming unit (cfu) counts; and flow cytometry for algal cell counts and identifying subpopulations.

<table border="0" cellpadding="0" cellspacing="0" width="1233">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:413px;">Name of Material/ Equipment</td>
			<td style="width:328px;">Company</td>
			<td style="width:331px;">Catalog Number</td>
			<td style="width:163px;">Comments/Description</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">10 cu. ft. Diurnal Incubator (6012-1)</td>
			<td>Caron Corporate</td>
			<td>112310-6012-1-11</td>
			<td><a href="http://www.caronproducts.com">www.caronproducts.com</a></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">Nunc EasYFlask 25cm2, Vent/Close Cap, 7mL working volume, 200/Cs&#160;</td>
			<td>Thermo Fisher Scientific</td>
			<td>N156340</td>
			<td><a href="http://www.fishersci.ca">www.fishersci.ca</a></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Multiwell TC Plates &#8211; 48 Well</td>
			<td>BD Biosciences Discovery Labware</td>
			<td>353078</td>
			<td><a href="http://www.bdbiosciences.com/">www.bdbiosciences.com</a></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">P1000 Gilson The Pipetting Standard&#8212;Gilson&#39;s Pipetman</td>
			<td>Mandel Scientific Company Inc.</td>
			<td>GF-F123602</td>
			<td><a href="http://www.mandel.ca">www.mandel.ca</a></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">P10mL Gilson The Pipetting Standard&#8212;Gilson&#39;s Pipetman</td>
			<td>Mandel Scientific Company Inc.</td>
			<td>GF-F161201</td>
			<td><a href="http://www.mandel.ca">www.mandel.ca</a></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Wide Orifice Tips nonsterile [100&#8211;1250 &#181;L]</td>
			<td>VWR International</td>
			<td>89079-468</td>
			<td><a href="http://www.ca.vwr.com">www.ca.vwr.com</a></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Ultrafine Tips nonsterile [100&#8211;1250 &#181;L]</td>
			<td>VWR International</td>
			<td>89079-470</td>
			<td><a href="http://www.ca.vwr.com">www.ca.vwr.com</a></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Finntip 10mL [Vol: 1-10mL]</td>
			<td>Thermo Fisher Scientific</td>
			<td>9402151</td>
			<td><a href="http://www.fishersci.ca">www.fishersci.ca</a></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">WATER-Pulse Amplitude Modulation (Water-ED)</td>
			<td>Heinz Walz GmbH, Effeltrich, Germany</td>
			<td>EDEE0232</td>
			<td><a href="http://www.walz.com">www.walz.com</a></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">15 mm diameter quartz glass cuvette (WATER-K)</td>
			<td>Caron Corporate</td>
			<td></td>
			<td><a href="http://www.caronproducts.com">www.caronproducts.com</a></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Sodium&#160;Chloride&#160;(Crystalline/Certified ACS), Fisher Chemical</td>
			<td>Thermo Fisher Scientific</td>
			<td>Thermo Fisher Scientific</td>
			<td><a href="http://www.fishersci.ca">www.fishersci.ca</a></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">BD Difco Marine Broth 2216</td>
			<td>BD Biosciences Discovery Labware</td>
			<td>BD Biosciences Discovery Labware</td>
			<td><a href="http://www.bdbiosciences.com">www.bdbiosciences.com</a></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">BD Bacto Agar</td>
			<td>BD Biosciences Discovery Labware</td>
			<td>BD Biosciences Discovery Labware</td>
			<td><a href="http://www.bdbiosciences.com">www.bdbiosciences.com</a></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">L1 Medium Kit, 50L</td>
			<td>NCMA [National Center for Marine Algae and Microbiota</td>
			<td>NCMA [National Center for Marine Algae and Microbiota</td>
			<td><a href="http://www.ncma.bigelow.org">www.ncma.bigelow.org</a></td>
		</tr>
	</tbody>
</table>

a small volume bioassay to assess bacterial/phytoplankton co-culture using water-pulse-amplitude-modulated (water-pam) fluorometry

Conventional methods for experimental manipulation of microalgae have employed large volumes of culture (20 ml to 5 L), so that the culture can be subsampled throughout the experiment1&#8211;7. Subsampling of large volumes can be problematic for several reasons: 1) it causes variation in the total volume and the surface area:volume ratio of the culture during the experiment; 2) pseudo-replication (i.e., replicate samples from the same treatment flask8) is often employed rather than true replicates (i.e., sampling from replicate treatments); 3) the duration of the experiment is limited by the total volume; and 4) axenic cultures or the usual bacterial microbiota are difficult to maintain during long-term experiments as contamination commonly occurs during subsampling.
The use of microtiter plates enables 1 ml culture volumes to be used for each replicate, with up to 48 separate treatments within a 12.65 x 8.5 x 2.2 cm plate, thereby decreasing the experimental volume and allowing for extensive replication without subsampling any treatment. Additionally, this technique can be modified to fit a variety of experimental formats including: bacterial-algal co-cultures, algal physiology tests, and toxin screening9&#8211;11. Individual wells with an alga, bacterium and/or co-cultures can be sampled for numerous laboratory procedures including, but not limited to: WATER-Pulse-Amplitude-Modulated (WATER-PAM) fluorometry, microscopy, bacterial colony forming unit (cfu) counts and flow cytometry. The combination of the microtiter plate format and WATER-PAM fluorometry allows for multiple rapid measurements of photochemical yield and other photochemical parameters with low variability between samples, high reproducibility and avoids the many pitfalls of subsampling a carboy or conical flask over the course of an experiment.

WATER-PAM fluorometry readings.
WATER-Pulse-Amplitude-Modulated (PAM) fluorometry is a quick and efficient method to determine the fluorescence (a proxy for chlorophyll content) and photosynthetic yield (PSII health) of algal cultures. The PAM WinControl software generates a spreadsheet of raw data values for (the following are the basic parameters for dark adapted algal samples):
&#160;&#160;&#160;&#160;F0 = fluorescence of dark-adapted cells
<p class="...

Watch this Scientific Journal Video about A Small Volume Bioassay to Assess Bacterial/Phytoplankton Co-culture Using WATER-Pulse-Amplitude-Modulated WATER-PAM Fluorometry at JoVE.com

A Small Volume Bioassay to Assess Bacterial/Phytoplankton Co-culture Using WATER-Pulse-Amplitude-Modulated WATER-PAM Fluorometry

The goal of this procedure is to demonstrate the reproducibility and adaptability of using a microtiter plate format for microalgal screening. This rapid screen combines WATER-Pulse-Amplitude-Modulated (WATER-PAM) fluorometry to measure photosynthetic yield as an indicator of Photosystem II (PSII) health with small volume bacterial-algal co-cultures.

A Small Volume Bioassay to Assess Bacterial/Phytoplankton Co-culture Using WATER-Pulse-Amplitude-Modulated (WATER-PAM) Fluorometry

Conventional methods for experimental manipulation of microalgae have employed large volumes of culture (20 ml to 5 L), so that the culture can be ...

a-small-volume-bioassay-to-assess-bacterialphytoplankton-co-culture

Research

JoVE Journal

Environment

A Small Volume Procedure for Viral Concentration from Water

Small-scale concentration of viruses (sample volumes 1-10 L, here simulated with spiked 100 ml water samples) is an efficient, cost-effective way to identify optimal parameters for virus concentration. Viruses can be concentrated from water using filtration (electropositive, electronegative, glass wool or size exclusion), followed by secondary concentration with beef extract to release viruses from filter surfaces, and finally tertiary concentration resulting in a 5-30 ml volume virus concentrate. In order to identify optimal concentration procedures, two different electropositive filters were evaluated (a glass/cellulose filter [1MDS] and a nano-alumina/glass filter [NanoCeram]), as well as different secondary concentration techniques; the celite technique where three different celite particle sizes were evaluated (fine, medium and large) followed by comparing this technique with that of the established organic flocculation method. Various elution additives were also evaluated for their ability to enhance the release of adenovirus (AdV) particles from filter surfaces. Fine particle celite recovered similar levels of AdV40 and 41 to that of the established organic flocculation method when viral spikes were added during secondary concentration. The glass/cellulose filter recovered higher levels of both, AdV40 and 41, compared to that of a nano-alumina/glass fiber filter. Although not statistically significant, the addition of 0.1% sodium polyphosphate amended beef extract eluant recovered 10% more AdV particles compared to unamended beef extract.

An approach was developed for identifying optimal viral concentration conditions for small volume water samples using spikes of human adenovirus. The techniques described here are used to identify concentration parameters for other viral targets, and applied to large-scale viral concentration experimentation.

Small-scale concentration of viruses (sample volumes 1-10 L, here simulated with spiked 100 ml water samples) is an efficient, cost-effective way to ...

A Whole Cell Bioreporter Approach to Assess Transport and Bioavailability of Organic Contaminants in Water Unsaturated Systems

Bioavailability of contaminants is a prerequisite for their effective biodegradation in soil. The average bulk concentration of a contaminant, however, is not an appropriate measure for its availability; bioavailability rather depends on the dynamic interplay of potential mass transfer (flux) of a compound to a microbial cell and the capacity of the latter to degrade the compound. In water-unsaturated parts of the soil, mycelia have been shown to overcome bioavailability limitations by actively transporting and mobilizing organic compounds over the range of centimeters. Whereas the extent of mycelia-based transport can be quantified easily by chemical means, verification of the contaminant-bioavailability to bacterial cells requires a biological method. Addressing this constraint, we chose the PAH fluorene (FLU) as a model compound and developed a water unsaturated model microcosm linking a spatially separated FLU point source and the FLU degrading bioreporter bacterium Burkholderia sartisoli RP037-mChe by a mycelial network of Pythium ultimum. Since the bioreporter expresses eGFP in response of the PAH flux to the cell, bacterial FLU exposure and degradation could be monitored directly in the microcosms via confocal laser scanning microscopy (CLSM). CLSM and image analyses revealed a significant increase of the eGFP expression in the presence of P. ultimum compared to controls without mycelia or FLU thus indicating FLU bioavailability to bacteria after mycelia-mediated transport. CLSM results were supported by chemical analyses in identical microcosms. The developed microcosm proved suitable to investigate contaminant bioavailability and to concomitantly visualize the involved bacteria-mycelial interactions.

A whole cell bioreporter assay with Burkholderia sartisoli RP037-mChe was developed to detect fractions of an organic contaminant (i.e., fluorene) available for bacterial degradation after active transport by mycelia bridging air-filled pores in a water unsaturated model system.

Bioavailability of contaminants is a prerequisite for their effective biodegradation in soil. The average bulk concentration of a contaminant, however, is ...

A Fish-feeding Laboratory Bioassay to Assess the Antipredatory Activity of Secondary Metabolites from the Tissues of Marine Organisms

Marine chemical ecology is a young discipline, having emerged from the collaboration of natural products chemists and marine ecologists in the 1980s with the goal of examining the ecological functions of secondary metabolites from the tissues of marine organisms. The result has been a progression of protocols that have increasingly refined the ecological relevance of the experimental approach. Here we present the most up-to-date version of a fish-feeding laboratory bioassay that enables investigators to assess the antipredatory activity of secondary metabolites from the tissues of marine organisms. Organic metabolites of all polarities are exhaustively extracted from the tissue of the target organism and reconstituted at natural concentrations in a nutritionally appropriate food matrix. Experimental food pellets are presented to a generalist predator in laboratory feeding assays to assess the antipredatory activity of the extract. The procedure described herein uses the bluehead, Thalassoma bifasciatum, to test the palatability of Caribbean marine invertebrates; however, the design may be readily adapted to other systems. Results obtained using this laboratory assay are an important prelude to field experiments that rely on the feeding responses of a full complement of potential predators. Additionally, this bioassay can be used to direct the isolation of feeding-deterrent metabolites through bioassay-guided fractionation. This feeding bioassay has advanced our understanding of the factors that control the distribution and abundance of marine invertebrates on Caribbean coral reefs and may inform investigations in diverse fields of inquiry, including pharmacology, biotechnology, and evolutionary ecology.

This bioassay employs a model predatory fish to assess the presence of feeding-deterrent metabolites from organic extracts of the tissues of marine organisms at natural concentrations using a nutritionally comparable food matrix.

Marine chemical ecology is a young discipline, having emerged from the collaboration of natural products chemists and marine ecologists in the 1980s with ...

Extracting Metrics for Three-dimensional Root Systems: Volume and Surface Analysis from In-soil X-ray Computed Tomography Data

Plant roots play a critical role in plant-soil-microbe interactions that occur in the rhizosphere, as well as processes with important implications to climate change and crop management. Quantitative size information on roots in their native environment is invaluable for studying root growth and environmental processes involving plants. X-ray computed tomography (XCT) has been demonstrated to be an effective tool for in situ root scanning and analysis. We aimed to develop a costless and efficient tool that approximates the surface and volume of the root regardless of its shape from three-dimensional (3D) tomography data. The root structure of a Prairie dropseed (Sporobolus heterolepis) specimen was imaged using XCT. The root was reconstructed, and the primary root structure was extracted from the data using a combination of licensed and open-source software. An isosurface polygonal mesh was then created for ease of analysis. We have developed the standalone application imeshJ, generated in MATLAB1, to calculate root volume and surface area from the mesh. The outputs of imeshJ are surface area (in mm2) and the volume (in mm3). The process, utilizing a unique combination of tools from imaging to quantitative root analysis, is described. A combination of XCT and open-source software proved to be a powerful combination to noninvasively image plant root samples, segment root data, and extract quantitative information from the 3D data. This methodology of processing 3D data should be applicable to other material/sample systems where there is connectivity between components of similar X-ray attenuation and difficulties arise with segmentation.

A methodology for obtaining visual and quantitative root structure information from X-ray computed tomography data acquired in-soil is presented.

Plant roots play a critical role in plant-soil-microbe interactions that occur in the rhizosphere, as well as processes with important implications to ...

How to Create Conditioned Taste Aversion for Grazing Ground Covers in Woody Crops with Small Ruminants

Conditioned taste aversion (CTA) is a learning behavior process where animals are trained to reject certain feed after gastrointestinal discomfort has been produced. Lithium chloride (LiCl) is the preferred agent used in livestock to induce CTA because it specifically stimulates the vomit center. In addition, LiCl is commercially available, and easy to prepare and administer using a drenching gun. Nevertheless, some factors have to be considered to obtain an effective long-lasting CTA, which allows small ruminants to graze during the cropping season. A key aspect is to use animals with no previous contact with the target plant (the plant chosen to be avoided; new feed). Due to their native neophobic feeding behavior, small ruminants can easily associate the negative feedback effects with the new feed, resulting in a strong and persistent CTA. The recommended doses are 200 and 225 mg LiCl/kg body weight (BW) for goats and sheep, respectively. To induce CTA, 100 g of the target plant should be individually offered for at least 30 min, and LiCl administered thereafter if the intake is greater than 10 g. Each time the animal eats the target plant without negative consequences, the CTA becomes weaker. Consequently, to minimize the risk of target plant consumption, it is essential to have sufficient palatable ground cover available. The presence of an alternative feed (of quality and quantity) prevents the accidental consumption of the target plant. A close monitoring of the flock is recommended to remove and re-dose any animal consuming more than 4 bites or 10 g of the target plant. At the beginning of each grazing season, check the CTA status of each animal before moving them to the crop.

Feeding behavior preferences in livestock can be modified to implement a grazing management plan in woody crops. Here, we present a protocol to show a lithium chloride dose after eating a new plant that induces conditioned taste aversion.

Conditioned taste aversion (CTA) is a learning behavior process where animals are trained to reject certain feed after gastrointestinal discomfort has ...

The Benthic Exchange of O2, N2 and Dissolved Nutrients Using Small Core Incubations

The measurement of sediment-water exchange of gases and solutes in aquatic sediments provides data valuable for understanding the role of sediments in nutrient and gas cycles. After cores with intact sediment-water interfaces are collected, they are submerged in incubation tanks and kept under aerobic conditions at in situ temperatures. To initiate a time course of overlying water chemistry, cores are sealed without bubbles using a top cap with a suspended stirrer. Time courses of 4-7 sample points are used to determine the rate of sediment water exchange. Artificial illumination simulates day-time conditions for shallow photosynthetic sediments, and in conjunction with dark incubations can provide net exchanges on a daily basis. The net measurement of N2 is made possible by sampling a time course of dissolved gas concentrations, with high precision mass spectrometric analysis of N2:Ar ratios providing a means to measure N2 concentrations. We have successfully applied this approach to lakes, reservoirs, estuaries, wetlands and storm water ponds, and with care, this approach provides valuable information on biogeochemical balances in aquatic ecosystems.

The Benthic Exchange of O2, N2 and Dissolved Nutrients Using Small Core Incubations

Here, we present small core incubations for the measurement of sediment-water gas and solute exchange. These will provide reliable measurements of sediment-water exchange that assess the role of sediment in influencing biological and biogeochemical processes in aquatic ecosystems.

The measurement of sediment-water exchange of gases and solutes in aquatic sediments provides data valuable for understanding the role of sediments in ...

Measuring the Flight Ability of the Ambrosia Beetle, Platypus Quercivorus (Murayama), Using a Low-Cost, Small, and Easily Constructed Flight Mill

The ambrosia beetle, Platypus quercivorus (Murayama), is the vector of a fungal pathogen that causes mass mortality of Fagaceae trees (Japanese oak wilt). Therefore, knowing the dispersal capacity may help inform trapping/tree removal efforts to prevent this disease more effectively. In this study, we measured the flight velocity and duration and estimated the flight distance of the beetle using a newly developed flight mill. The flight mill is low cost, small, and constructed using commonly available items. Both the flight mill arm and its vertical axis comprise a thin needle. A beetle specimen is glued to one tip of the arm using instant glue. The other tip is thick due to being covered with plastic, thus it facilitates the detection of rotations of the arm. The revolution of the arm is detected by a photo sensor mounted on an infrared LED, and is indicated by a change in the output voltage when the arm passed above the LED. The photo sensor is connected to a personal computer and the output voltage data are stored at a sampling rate of 1 kHz. By conducting experiments using this flight mill, we found that P. quercivorus can fly at least 27 km. Because our flight mill comprises cheap and small ordinary items, many flight mills can be prepared and used simultaneously in a small laboratory space. This enables experimenters to obtain a sufficient amount of data within a short period.

Measuring the Flight Ability of the Ambrosia Beetle, Platypus Quercivorus Murayama, Using a Low-Cost, Small, and Easily Constructed Flight Mill

We developed a low cost and small flight mill, constructed with commonly available items and easily used in experimentation. Using this apparatus, we measured the flight ability of an ambrosia beetle, Platypus quercivorus.

The ambrosia beetle, Platypus quercivorus (Murayama), is the vector of a fungal pathogen that causes mass mortality of Fagaceae trees (Japanese oak wilt). ...

A Flexible Low Cost Hydroponic System for Assessing Plant Responses to Small Molecules in Sterile Conditions

A wide range of studies in plant biology are performed using hydroponic cultures. In this work, an in vitro hydroponic growth system designed for assessing plant responses to chemicals and other substances of interest is presented. This system is highly efficient in obtaining homogeneous and healthy seedlings of the C3 and C4 model species Arabidopsis thaliana and Setaria viridis, respectively. The sterile cultivation avoids algae and microorganism contamination, which are known limiting factors for plant normal growth and development in hydroponics. In addition, this system is scalable, enabling the harvest of plant material on a large scale with minor mechanical damage, as well as the harvest of individual parts of a plant if desired. A detailed protocol demonstrating that this system has an easy and low-cost assembly, as it uses pipette racks as the main platform for growing plants, is provided. The feasibility of this system was validated using Arabidopsis seedlings to assess the effect of the drug AZD-8055, a chemical inhibitor of the target of rapamycin (TOR) kinase. TOR inhibition was efficiently detected as early as 30 min after an AZD-8055 treatment in roots and shoots. Furthermore, AZD-8055-treated plants displayed the expected starch-excess phenotype. We proposed this hydroponic system as an ideal method for plant researchers aiming to monitor the action of plant inducers or inhibitors, as well as to assess metabolic fluxes using isotope-labeling compounds which, in general, requires the use of expensive reagents.

A simple, versatile, and low-cost in vitro hydroponic system was successfully optimized, enabling large-scale experiments under sterile conditions. This system facilitates the application of chemicals in a solution and their efficient absorption by roots for molecular, biochemical, and physiological studies.

A wide range of studies in plant biology are performed using hydroponic cultures. In this work, an in vitro hydroponic growth system designed for ...

Reproducible dsRNA Microinjection and Oviposition Bioassay in Mosquitoes and House Flies

Synthetic dsRNAs, used to induce RNA interference, may have dose dependent phenotypic effects. These effects are difficult to define if the dsRNAs are delivered using a non-quantitative method. Accurate delivery of known quantities of nucleic acids or other chemicals is critical to measure the efficacy of the compound being tested and to allow reliable comparison between compounds.
Here we provide a reproducible, quantitative microinjection protocol that ensures accurate delivery of specific doses of dsRNA, reducing the mortality typically induced by injection injury. These modifications include the addition of Rhodamine B, a graduated injection needle, and an improved recovery method borrowed from Isoe and Collins. This method allows calculation of dose responses and facilitates comparisons between compounds. Versions of this method have been successfully used on three genera of mosquitoes as well as house flies to assess the reduction in fecundity resulting from gene silencing of ribosomal RNA transcripts.
This protocol provides strategies to reduce several challenges of small insect microinjection. Together, mechanical delivery of dsRNAs accompanied by visual verification, identification of effective locations for delivery, and inclusion of a post-injection recovery period ensure accurate dosing and low injury mortality. This protocol also describes an oviposition bioassay for uniform determination of effects on fecundity.

This protocol describes a microinjection methodology that we have standardized and used for several years to deliver specific quantities of nucleic acids directly to the hemolymph of mosquitoes and house flies. This protocol results in minimal injection mortality and allows dose correlated measurements of fecundity.

Synthetic dsRNAs, used to induce RNA interference, may have dose dependent phenotypic effects. These effects are difficult to define if the dsRNAs are ...

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, ...