Wir danken für die Fotos von Austern und Messen ihre klaffen Breite in ImageJ Melinda Forseth. Wir danken Denise Breitburg für den Zugriff auf die Aquarien mit Diel Radfahren Hypoxie und zyklischen pH-Bedingungen. Wir danken dem Smithsonian Environmental Research Center, Edgewater, Maryland, Raum für Experimente. Die Hypoxie-Experimente wurden von einem National Oceanic and Atmospheric Administration - Zentrum für gesponserte Coastal Ocean Research Grant Nein finanziert. NA10NOS4780138 und dem Smithsonian Hunterdon Fonds, Denise Breitburg. Das Ventil klaffen Messungen während der Hypoxie, die Experimente durch eine Fakultät für Verbesserung von Washington College, Elka T. Porter finanziert wurden.

Wir haben nicht alles offenlegen.

Typische Studien Fokus auf kontinuierliche, erweitert Zeiträume der sauerstoffarmen Bedingungen und die Antwort, die oft als das Überleben der Tiere gemessen. Zur Zeit ist unser Verständnis von Verhaltensreaktionen von Tieren zur Hypoxie Diel Radfahren jedoch minimal63. Daher sollten weitere Studien auf das Verhalten der Organismen als Reaktion auf Hypoxie Diel-Radfahren konzentrieren, die tritt regelmäßig im Laufe des Sommers in vielen Flussmündungen7,<sup...

Hypoxie, d.h. aufgelöst Sauerstoffkonzentrationen [] ausreichend niedrige um sich negativ auf biologische und ökologische Prozesse aber oft funktionell definiert als [tun] < 2 mg / L1und Sauerstoffmangel (funktional definiert als [tun] 0,0-0,2 mg/L) treten immer häufiger und stark in der Welt Küstengewässer, Flussmündungen und die Tiefen des Ozeans2,3 auf und sind oft verschärft durch die zunehmende Eutrophierung4,5. Mit areal in zunehmendem Maße von Hypoxie und Anoxie Makrofauna negativ beeinflusst und verlieren Lebensraum Umfang und Lebensraumqualität. Der Klimawandel wird voraussichtlich Hypoxie und Anoxie6verschlechtern.
In vielen geschichtete, Nährstoff angereicherte Flussmündungen wie Chesapeake Bay, USA saisonal anhaltende Hypoxie kann sich durchsetzen und Jahr für Jahr2auftreten kann. Darüber hinaus Diel-Radfahren von Hypoxie ist häufig in Flussmündungen wie der Chesapeake Bay und an anderen Orten und tritt spät während der Nacht oder den frühen Morgenstunden in der Sommer-7,-8.
Die meisten Studien konzentrierten sich auf die Wirkung der Dauerbelastung von Organismen zu niedrigen [tun] und auf ihre Toleranz gegenüber Hypoxie und Anoxie9,10,11,12,13,14 . Darüber hinaus haben Studien der großen Verschiebung der Artenzusammensetzung Distributionen, Häufigkeiten und Arten als Reaktion auf Erweiterte niedrig [tun]4,15angeschaut. Oft Arten, die sehr empfindlich auf niedrige in Massen sterben [],16 verlagert die übrigen Arten, eine jüngere, kleinere, kurzlebige Fauna wie zum Beispiel auf der Louisiana-Texas Regal Ökosystem4gefunden.
Verhaltensänderungen in der Regel vorausgehen Gemeinschaft Zusammenbruch17 und Studien haben berichtet, auf Verhaltensreaktionen von Organismen auf Erweiterte niedrig [tun]4,16,17,18,19 ,20,21,22,23,24,25. Diese Studien jedoch konzentrieren nicht auf den Antworten von Organismen Diel-cycling Belichtungen von Hypoxie und dem schwankenden Charakter [tun] Verfügbarkeit in Flussmündungen.
Diel-Radfahren Hypoxie in seichten Flussmündungen erhielt Sensibilisierung als Studien zu [tun] mehr überwachen häufig im Laufe der Tage mit Sonden in Flussmündungen16,26. Wasser kann für Stunden am Ende der Nacht oder am frühen Morgenstunden im Sommer hypoxischen bleiben wenn es keine Photosynthese Sauerstoff erzeugenden während der Nacht aber hohe Sauerstoff verbrauchenden gibt aerobe Atmung7,16. Ferner wurde festgestellt, dass die Gezeiten die Diel beeinflusst Radfahren niedrig-Bedingungen mit den extremen Minima beobachtet, wenn Ebbe fiel mit dem Ende der Nacht27. Erst nach mehreren Stunden der Hypoxie [tut] normoxiezustand7,16,28 im täglichen Zyklus zurückkommen.
Bestimmen die Verhaltensreaktion C. Virginica Diel Radfahren Hypoxie und pH-Wert wir überwacht das Öffnen und Schließen der Ventile von Austern ans Labor induzierte Diel Radfahren [tun] und zyklischen pH. Gape Antworten von Muscheln wurden zur ungünstigen Umweltbedingungen erkennen. Ventil-Schließungen von Muscheln als Reaktion auf Verunreinigungen29,30,31, giftige Algen32,33,34, thermische Verunreinigung35,36 , 37, Essen Quantität verringern38,39,40, Fütterung Regime39,41, auftauchen37,42, Photoperiode43 , 44, pH45,46, und kombinierte pH und gelösten Sauerstoff47 wurden gemessen. Gape Techniken haben, direkte Beobachtungen48,49,13, kontinuierliche Messungen mit Reed-Schalter und Magnete (Dreissena Monitor)50oder faseroptischen Sensoren beispielsweise enthalten. 51 , die klares Wasser benötigen. Darüber hinaus wurden Magnet und Magnetfeld Stärke-Hall-Sensoren zur Muschel Gape Winkel52,53,54,55, und eine hochfrequente elektromagnetische Induktionssystem studieren dass die unterschiedlichen Distanz zwischen zwei elektrischen Spulen, die auf den Ventilen geklebt werden bislang56,57,58,59verwendet. Eine Hochspannungsquelle ist erforderlich für die elektromagnetische Induktionssystem und macht hat an beiden Seiten der Schale52geliefert werden. Dieses System ist auch als "MOSSELMONITOR" (http://mosselmonitor.nl/) im Handel erhältlich.
Auf einem engen Forschungsbudget wir einen kostengünstige DMS-Monitor (SGM) kontinuierlich zu Auster Gape Messen über Labor-induzierte Diel gebaut [tun] Radfahren und pH unter schlechten Sichtverhältnissen. Unser System ist auch viel einfacher als konkurrierende Systeme, so dass viele Tiere während eines Experiments instrumentiert werden. Wir wollten herausfinden, die Verhaltensreaktionen von C. Virginica , Diel Radfahren schwere ([] = 0,6 mg/L) Hypoxie mit Kontrolle pH (pH = 7,8) und Radsport pH (pH = 7,8-7.0) bzw. und Gape Antworten zu Mild ([] = 1,7 mg/L) Hypoxie. Darüber hinaus wollten wir um festzustellen, ob Austern in der Lage sind, auf Veränderungen schnell reagieren, [] über die Diel Zyklus und wie sie reagieren, wenn normoxiezustand nach einem hypoxischen Event kehrt zurück. Vielleicht sind Austern optimal angepasst an die stark schwankenden Umgebung, die in vielen Flussmündungen16,27 gefunden wird, wo sie leben. Während komplexer Ventil Gape Monitore zur Verfügung stehen, bietet der SGM eine preiswerte Technik, die Dauermessungen Ventil klaffen in den Gewässern auch bei schlechten Sichtverhältnissen ermöglicht.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/57404/57404fig1.jpg"> Abbildung 1. Wheatstone-Brücke für den Ventil Gape Apparat. <a href="/files/ftp_upload/57404/57404fig1large.jpg" target="_blank">Bitte klicken Sie hier für eine größere Version dieser Figur.</a>
Die DMS-Sensoren zur Überwachung von zweischaligen Gape eingesetzt sind resistive Filme in einem Mäander-Muster auf einem Polyimid sichern. Geringe Mengen an Stamm modulieren den Widerstand des Sensors. Die Muscheln beugt DMS, wenn es klafft verursacht eine Änderung in der Widerstand des Sensors. Wir Beschäftigten eine Abgleich, ausgewogene, Wheatstone-Brücke für jeden zweischaligen Kanal, wie in Abbildung 1 dargestellt, um den Wandel im Widerstand des Sensors messen. Die Wheatstone-Brücke ist durch das Potentiometer ermöglicht eine relativ hohe Verstärkung durch den Datenlogger eingesetzt werden wwww. Eine Wheatstone-Brücke ist eine Standardmethode für die präzise Messung einen unbekannten Widerstand Verhältnis zu einem bekannten Widerstand standard und ein Voltmeter. Die Geschichte dieser uralten Technik ist in Ekelof (2001)60diskutiert. Wir haben 12 Kanäle, jeweils mit eigenem Wheatstone-Brücke und Abgleich Potentiometer in DMS-Monitor (SGM) Einheit integriert.

<table><tbody><tr><td>Campbell CR 10x data logger</td><td>Campbell Scientific, Logan, Utah</td><td></td><td>Or other data logger. At Campbell the CR 10X has been replaced with the CR 1000</td></tr><tr><td>Campbell CR 10x multiplexer</td><td>Campbell Scientific, Logan, Utah</td><td></td><td>Data logger needs to have space for 12 channels</td></tr><tr><td>Dsub connector male crimp pins</td><td>TE Connectivity</td><td>205089-1</td><td>pins for gape sensor leads</td></tr><tr><td>PCA tape</td><td>Micro Measurements Corp, NC</td><td></td><td>To seal the strain gauge</td></tr><tr><td>Duro Quick Gel</td><td>Ace Hardware</td><td></td><td>Superglue</td></tr><tr><td>SG13/1000-LY43 or LY41</td><td>Omega Engineering Inc., Stanford, CT</td><td></td><td>Strain gauges</td></tr><tr><td>32 AWG (7/40) teflon Alpha wires</td><td>AlphaWire, Elizabeth, NJ</td><td>2840/7</td><td>Sensor cables, different colors are available</td></tr><tr><td>1/16&quot; heat shrink tubing</td><td>Qualtek</td><td>B01A3QKKO6</td><td>To seal the leads of the sensor cable</td></tr><tr><td>Weller WES51 Analog Soldering Station</td><td>Amazon</td><td></td><td>Lots of soldering, need a good soldering iron. https://www.amazon.com/Weller-WES51-Analog-Soldering-Station/dp/B000BRC2XU/ref=sr_1_23?s=hi&amp;amp;ie=UTF8&amp;amp;qid=1505654295&lt;br/&gt; &amp;amp;sr=1-23&amp;amp;keywords=soldering+iron</td></tr><tr><td>Rosin Soldering Flux Paste</td><td>Amazon</td><td></td><td>Needed for soldering</td></tr><tr><td>60-40 Tin Lead Rosin Core Solder Wire</td><td>Amazon</td><td></td><td>Needed for soldering</td></tr><tr><td>Aquarium sealant</td><td>Home Depot</td><td></td><td>Attach sensors to bivalve</td></tr><tr><td>PC Laptop</td><td></td><td></td><td>Any old PC to run Campbell gape program</td></tr><tr><td>heat gun</td><td>Amazon</td><td></td><td>shrink shrink tubing</td></tr><tr><td>Drill</td><td>Hardware store, Amazon</td><td></td><td>for twisting wires to make sensor cables</td></tr><tr><td>AC to DC power module</td><td>Acopian</td><td>DB15-30</td><td>Wheatstone bridge power supply</td></tr><tr><td>Poteniometer</td><td>Clarostat</td><td>733A</td><td>Wheatsone bridge nulling</td></tr><tr><td>isolating BNC connector</td><td>Sterren Electronics</td><td>&quot;200-148</td><td>Wheatstone bridge output for multimeter</td></tr><tr><td>Fused AC receptical panel module</td><td>Adam technologies</td><td>IEC-GS-1-200</td><td>Wheatstone bridge power supply connector</td></tr><tr><td>976 ohm 1% resistor</td><td>Vishay Dale</td><td>CMF50976R00FHEB</td><td>Wheatstone bridge resistor</td></tr><tr><td>1 kohm 1% resistor</td><td>Vishay Dale</td><td>CMF501K0000FHEB</td><td>Wheatstone bridge resistor</td></tr><tr><td>Potentiometer scale dial</td><td>Kilo International</td><td>462</td><td>10 turn dial for nulling potentiometer</td></tr><tr><td>DB25 male panel connector</td><td>TE connectivity</td><td>1757819-8</td><td>Data logger connector on Wheatstone bridge</td></tr><tr><td>DB25 female panel connector</td><td>TE connectivity</td><td>1757819-8</td><td>Sensor connector to Wheatstone bridge</td></tr><tr><td>perforated circuit board</td><td>Vector electronics</td><td>64P44WE</td><td>circuit board for mounting of bridge components</td></tr><tr><td>enclosure</td><td>Hammond Manufacturing</td><td>1444-29</td><td>Enclosure for sensor readout electronics</td></tr></tbody></table>

a strain gauge monitor (sgm) for continuous valve gape measurements in bivalve molluscs in response to laboratory induced diel-cycling hypoxia and ph

Ein preiswerte, Labor-basierte DMS Ventil Gape Monitor (SGM) wurde entwickelt, um das Ventil Gape Verhalten von Muscheln als Reaktion auf Hypoxie Diel-Radfahren zu überwachen. Eine Wheatstone-Brücke wurde mit Dehnungsmessstreifen verbunden, die die Schalen der Austern (Crassostrea Virginica) zugeordnet wurden. Die aufgezeichneten Signale erlaubt für das Öffnen und Schließen der Muscheln, kontinuierlich über aufgezeichnet werden jeweils zweitägigen Perioden der experimentell induzierten Diel Radfahren Hypoxie und Diel Radfahren Veränderung des pH-Wertes. Hier wir beschreiben ein Protokoll für eine kostengünstige DMS-Monitor zu entwickeln und in einem Laborexperiment Beispiel beschreiben, wie wir es verwendet, um das Ventil Gape Verhalten Messen Eastern Austern (C. Virginica), als Reaktion auf Hypoxie Diel-Radfahren und zyklische Veränderungen des pH-Wertes. Ventil Gape auf Austern ausgesetzt zyklischen schweren hypoxischen (0,6 mg/L) gemessen wurde aufgelöst sauerstoffbedingungen mit und ohne zyklische Veränderungen im pH-Wert, zyklische milde Hypoxie (1,7 mg/L) und Inklusieve (7,3 mg/L) Bedingungen. Wir zeigen, dass wenn Austern wiederholte Diel Zyklen begegnen, sie schnell ihre Schalen als Reaktion auf schwere Hypoxie schließen und mit einer zeitlichen Verzögerung zur Milde Hypoxie schließen. Wenn normoxiezustand wiederhergestellt wird, öffnen sie schnell wieder. Austern reagierte nicht auf zyklische pH-Bedingungen Diel Radfahren schwere Hypoxie überlagert. Bei reduzierten sauerstoffbedingungen mehr als ein Drittel der Austern gleichzeitig geschlossen. Wir zeigen, dass Austern auf Diel Radfahren Hypoxie reagieren, die berücksichtigt werden müssen bei der Beurteilung des Verhaltens der Muscheln zu Sauerstoff aufgelöst. Das Ventil SGM kann verwendet werden, um Antworten von Muscheln auf Änderungen an gelöstem Sauerstoff oder Verunreinigungen zu beurteilen. Dichtungstechniken für bessere Abdichtung brauchen Ventil Gape Dehnungsmessstreifen aus Meerwasser weitere Verbesserungen erhöhen die Lebensdauer der Sensoren.

Austern, die ununterbrochene Inklusieve Mündungs Wasser (keine Hypoxie während der niedrigen Plateauphase des täglichen Zyklus) ausgesetzt waren die meiste Zeit offen und selten nur kurz geschlossen (Abbildung 5). Wenn sie abwechslungsreiche von Auster, Austern geschlossen. Dieses Muster ist auch in Loosanoff und Nomejko 194644 und Higgins 198039festgestellt worden. Austern reagierte auch nicht auf die Differ...

Watch this Scientific Journal Video about A Strain Gauge Monitor SGM for Continuous Valve Gape Measurements in Bivalve Molluscs in Response to Laboratory Induced Diel-cycling Hypoxia and pH at JoVE.co

A Strain Gauge Monitor SGM for Continuous Valve Gape Measurements in Bivalve Molluscs in Response to Laboratory Induced Diel-cycling Hypoxia and pH

Ein DMS-Monitor (SGM) für Ventil klaffen Dauermessungen in Muscheln Muscheln als Reaktion auf Hypoxie Labor induzierte Diel-Radfahren und pH-Wert

Verständnis der Verhaltensreaktionen von zweischaligen Aussetzung-Zubringer zu Umgebungsvariablen wie gelöster Sauerstoff, kann einige Ökosystemprozesse erklären. Wir haben einen kostengünstige, Labor-basierte, DMS-Monitor (SGM) Ventil Gape Antworten von Austern, Crassostrea Virginica, Messen, Diel Radfahren Hypoxie und zyklischen pH entwickelt.

An inexpensive, laboratory-based, strain gauge valve gape monitor (SGM) was developed to monitor the valve gape behavior of bivalve molluscs in response ...

a-strain-gauge-monitor-sgm-for-continuous-valve-gape-measurements

Research

JoVE Journal

Environment

A Strain Gauge Monitor (SGM) for Continuous Valve Gape Measurements in Bivalve Molluscs in Response to Laboratory Induced Diel-cycling Hypoxia and pH

8.9K Aufrufe.  University of Baltimore. Verständnis der Verhaltensreaktionen von zweischaligen Aussetzung-Zubringer zu Umgebungsvariablen wie gelöster Sauerstoff, kann einige Ökosystemprozesse erklären. Wir haben einen kostengünstige, Labor-basierte, DMS-Monitor (SGM) Ventil Gape Antworten von Austern, Crassostrea Virginica, Messen, Diel Radfahren Hypoxie und zyklischen pH entwickelt.

Serie: A Strain Gauge Monitor SGM for Continuous Valve Gape Measurements in Bivalve Molluscs in Response to Laboratory Induced Diel-cycling Hypoxia and pH

A Simple Approach to Manipulate Dissolved Oxygen for Animal Behavior Observations

The ability to manipulate dissolved oxygen (DO) in a laboratory setting has significant application to investigate a number of ecological and organismal behavior questions. The protocol described here provides a simple, reproducible, and controlled method to manipulate DO to study behavioral response in aquatic organisms resulting from hypoxic and anoxic conditions. While performing degasification of water with nitrogen is commonly used in laboratory settings, no explicit method for ecological (aquatic) application exists in the literature, and this protocol is the first to describe a protocol to degasify water to observe organismal response. This technique and protocol were developed for direct application for aquatic macroinvertebrates; however, small fish, amphibians, and other aquatic vertebrates could be easily substituted. It allows for easy manipulation of DO levels ranging from 2 mg/L to 11 mg/L with stability for up to a 5 min animal-observation period. Beyond a 5 min observation period water temperatures began to rise, and at 10 min DO levels became too unstable to maintain. The protocol is scalable to the study organism, reproducible, and reliable, allowing for rapid implementation into introductory teaching labs and high-level research applications. The expected results of this technique should relate dissolved oxygen changes to behavioral responses of organisms.

This article describes a simple and reproducible protocol to manipulate dissolved oxygen conditions in a laboratory setting for animal behavior studies. This protocol may be used in both teaching and research laboratory settings to evaluate organismal response of macroinvertebrates, fishes, or amphibians to changes in dissolved oxygen concentration.

Ein einfacher Ansatz zur Manipulation von gelöstem Sauerstoff für Tierverhaltensbeobachtungen

The ability to manipulate dissolved oxygen (DO) in a laboratory setting has significant application to investigate a number of ecological and organismal ...

Forschung

Umwelt

Design and Use of an Apparatus for Quantifying Bivalve Suspension Feeding at Sea

As shellfish aquaculture moves from coastal embayments and estuaries to offshore locations, the need to quantify ecosystem interactions of farmed bivalves (i.e., mussels, oysters, and clams) presents new challenges. Quantitative data on the feeding behavior of suspension-feeding mollusks is necessary to determine important ecosystem interactions of offshore shellfish farms, including their carrying capacity, the competition with the zooplankton community, the availability of trophic resources at different depths, and the deposition to the benthos. The biodeposition method is used to quantify feeding variables in suspension-feeding bivalves in a natural setting and represents a more realistic proxy than laboratory experiments. This method, however, relies upon a stable platform to satisfy the requirements that water flow rates supplied to the shellfish remain constant and the bivalves are undisturbed. A flow-through device and process for using the biodeposition method to quantify the feeding of bivalve mollusks were modified from a land-based format for shipboard use by building a two-dimensional gimbal table around the device. Planimeter data reveal a minimal pitch and yaw of the chambers containing the test shellfish despite boat motion, the flow rates within the chambers remain constant, and operators are able to collect the biodeposits (feces and pseudofeces) with sufficient consistency to obtain accurate measurements of the bivalve clearance, filtration, selection, ingestion, rejection, and absorption at offshore shellfish aquaculture sites.

A flow-through device for using the biodeposition method to quantify filtration and feeding behavior of bivalve mollusks was modified for shipboard use. A two-dimensional gimbal table built around the device isolates the apparatus from boat motion, thereby allowing the accurate quantification of bivalve filtration variables at offshore shellfish aquaculture sites.

Gestaltung und Nutzung eines Apparates zur Quantifizierung der zweischaligen Suspension Fütterung auf hoher See

As shellfish aquaculture moves from coastal embayments and estuaries to offshore locations, the need to quantify ecosystem interactions of farmed bivalves ...

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.

Mikroalgen-Anbau und Biomasse-Quantifizierung in einem Bench-Scale Photobioreaktor mit ätzenden Rauchgasen

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

Fabrication and Implantation of Miniature Dual-element Strain Gages for Measuring In Vivo Gastrointestinal Contractions in Rodents.

Gastrointestinal dysfunction remains a major cause of morbidity and mortality. Indeed, gastrointestinal (GI) motility in health and disease remains an area of productive research with over 1,400 published animal studies in just the last 5 years. Numerous techniques have been developed for quantifying smooth muscle activity of the stomach, small intestine, and colon. In vitro and ex vivo techniques offer powerful tools for mechanistic studies of GI function, but outside the context of the integrated systems inherent to an intact organism. Typically, measuring in vivo smooth muscle contractions of the stomach has involved an anesthetized preparation coupled with the introduction of a surgically placed pressure sensor, a static pressure load such as a mildly inflated balloon or by distending the stomach with fluid under barostatically-controlled feedback. Yet many of these approaches present unique disadvantages regarding both the interpretation of results as well as applicability for in vivo use in conscious experimental animal models. The use of dual element strain gages that have been affixed to the serosal surface of the GI tract has offered numerous experimental advantages, which may continue to outweigh the disadvantages. Since these gages are not commercially available, this video presentation provides a detailed, step-by-step guide to the fabrication of the current design of these gages. The strain gage described in this protocol is a design for recording gastric motility in rats. This design has been modified for recording smooth muscle activity along the entire GI tract and requires only subtle variation in the overall fabrication. Representative data from the entire GI tract are included as well as discussion of analysis methods, data interpretation and presentation.

Fabrication and Implantation of Miniature Dual-element Strain Gages for Measuring In Vivo Gastrointestinal Contractions in Rodents.

The in vivo measurement of smooth muscle contractions along the gastrointestinal tract of laboratory animals remains a powerful, though underutilized, technique. Flexible, dual element strain gages are not commercially available and require fabrication. This protocol describes the construction of reliable, inexpensive strain gages for acute or chronic implantation in rodents.

Herstellung und Implantation von Miniatur-Zweielement Dehnungsmessstreifen für Mess<em&gt; In Vivo</em&gt; Magen-Darm-Kontraktionen in Nagetiere.

Gastrointestinal dysfunction remains a major cause of morbidity and mortality. Indeed, gastrointestinal (GI) motility in health and disease remains an ...

Biotechnik

Impedance Pneumography for Minimally Invasive Measurement of Heart Rate in Late Stage Invertebrates

Temperatures in oceans are increasing rapidly as a consequence of widespread changes in world climates. As organismal physiology is heavily influenced by environmental temperature, this has the potential to alter thermal physiological performance in a variety of marine organisms. Using the American lobster (Homarus americanus) as a model organism, this protocol describes the use of impedance pneumography to understand how cardiac performance in late stage invertebrates changes under acute thermal stress. The protocol presents a minimally invasive technique that allows for real-time collection of heart rate during a temperature ramping experiment. Data are easily manipulated to generate an Arrhenius plot that is used to calculate Arrhenius break temperature (ABT), the temperature at which heart rate begins to decline with increasing temperatures. This technique can be used in a variety of late stage invertebrates (i.e., crabs, mussels, or shrimps). Although the protocol focuses solely on the impact of temperature on cardiac performance, it can be modified to understand the potential for additional stressors (e.g., hypoxia or hypercapnia) to interact with temperature to influence physiological performance. Thus, the method has potential for wide-ranging applications to further understand how marine invertebrates respond to acute changes in the environment.

Measuring heart rate during a thermal challenge provides insight into physiological responses of organisms as a consequence of acute environmental change. Using the American lobster (Homarus americanus) as a model organism, this protocol describes the use of impedance pneumography as a relatively noninvasive and nonlethal approach to measure heart rate in late stage invertebrates.

Impedanz-Pneumographie zur minimalinvasiven Messung der Herzfrequenz bei Wirbellosen im Spätstadium

Temperatures in oceans are increasing rapidly as a consequence of widespread changes in world climates. As organismal physiology is heavily influenced by ...

Supramaximal Intensity Hypoxic Exercise and Vascular Function Assessment in Mice

Exercise training is an important strategy for maintaining health and preventing many chronic diseases. It is the first line of treatment recommended by international guidelines for patients suffering from cardiovascular diseases, more specifically, lower extremity artery diseases, where the patients' walking capacity is considerably altered, affecting their quality of life. 
Traditionally, both low continuous exercise and interval training have been used. Recently, supramaximal training has also been shown to improve athletes' performances via vascular adaptations, amongst other mechanisms. The combination of this type of training with hypoxia could bring an additional and/or synergic effect, which could be of interest for certain pathologies. Here, we describe how to perform supramaximal intensity training sessions in hypoxia on healthy mice at 150% of their maximal speed, using a motorized treadmill and a hypoxic box. We also show how to dissect the mouse in order to retrieve organs of interest, particularly the pulmonary artery, the abdominal aorta, and the iliac artery. Finally, we show how to perform ex vivo vascular function assessment on the retrieved vessels, using isometric tension studies.

High-intensity training in hypoxia is a protocol that has been proven to induce vascular adaptations potentially beneficial in some patients and to improve athletes&#39; repeated sprint ability. Here, we test the feasibility of training mice using that protocol and identify those vascular adaptations using ex vivo vascular function assessment.

Supramaximalen hypoxischer Intensität und Gefäßfunktion Bewertung bei Mäusen

Exercise training is an important strategy for maintaining health and preventing many chronic diseases. It is the first line of treatment recommended by ...

Verhalten

The ex vivo Isolated Skeletal Microvessel Preparation for Investigation of Vascular Reactivity

The isolated microvessel preparation is an ex vivo preparation that allows for examination of the different contributions of factors that control vessel diameter, and thus, perfusion resistance1-5. This is a classic experimental preparation that was, in large measure, initially described by Uchida et al.15 several decades ago. This initial description provided the basis for the techniques that was extensively modified and enhanced, primarily in the laboratory of Dr. Brian Duling at the University of Virginia6-8, and we present a current approach in the following pages. This preparation will specifically refer to the gracilis arteriole in a rat as the microvessel of choice, but the basic preparation can readily be applied to vessels isolated from nearly any other tissue or organ across species9-13. Mechanical (i.e., dimensional) changes in the isolated microvessels can easily be evaluated in response to a broad array of physiological (e.g., hypoxia, intravascular pressure, or shear) or pharmacological challenges, and can provide insight into mechanistic elements comprising integrated responses in an intact, although ex vivo, tissue. The significance of this method is that it allows for facile manipulation of the influences on the integrated regulation of microvessel diameter, while also allowing for the control of many of the contributions from other sources, including intravascular pressure (myogenic), autonomic innervation, hemodynamic (e.g., shear stress), endothelial dependent or independent stimuli, hormonal, and parenchymal influences, to provide a partial list. Under appropriate experimental conditions and with appropriate goals, this can serve as an advantage over in vivo or in situ tissue/organ preparations, which do not readily allow for the facile control of broader systemic variables. 
The major limitation of this preparation is essentially the consequence of its strengths. By definition, the behavior of these vessels is being studied under conditions where many of the most significant contributors to the regulation of vascular resistance have been removed, including neural, humoral, metabolic, etc. As such, the investigator is cautioned to avoid over-interpretation and extrapolation of the data that are collected utilizing this preparation. The other significant area of concern with regard to this preparation is that it can be very easy to damage cellular components such as the endothelial lining or the vascular smooth muscle, such that variable source of error can be introduced. It is strongly recommended that the individual investigator utilize appropriate measurements to ensure the quality of the preparation, both at the initiation of the experiment and periodically throughout the course of a protocol.

The ex vivo Isolated Skeletal Microvessel Preparation for Investigation of Vascular Reactivity

An ex vivo preparation is described for isolation of the largest gracilis muscle resistance arterioles for interrogation of both vascular responses to vasoactive stimuli and the assessment of basic structural properties via passive wall mechanics.

Die Ex vivo Isoliert Skeletal Mikrogefäßdichte Vorbereitung für Untersuchung der vaskulären Reaktivität

The isolated  microvessel preparation is an ex vivo preparation that allows for examination of the different contributions of  factors that control vessel ...

Biologie

Mechano-Node-Pore Sensing: A Rapid, Label-Free Platform for Multi-Parameter Single-Cell Viscoelastic Measurements

Cellular mechanical properties are involved in a wide variety of biological processes and diseases, ranging from stem cell differentiation to cancer metastasis. Conventional methods for measuring these properties, such as atomic force microscopy (AFM) and micropipette aspiration (MA), capture rich information, reflecting a cell's full viscoelastic response; however, these methods are limited by very low throughput. High-throughput approaches, such as real-time deformability cytometry (RT-DC), can only measure limited mechanical information, as they are often restricted to single-parameter readouts that only reflect a cell's elastic properties. In contrast to these methods, mechano-node-pore sensing (mechano-NPS) is a flexible, label-free microfluidic platform that bridges the gap in achieving multi-parameter viscoelastic measurements of a cell with moderate throughput. A direct current (DC) measurement is used to monitor cells as they transit a microfluidic channel, tracking their size and velocity before, during, and after they are forced through a narrow constriction. This information (i.e., size and velocity) is used to quantify each cell's transverse deformation, resistance to deformation, and recovery from deformation. In general, this electronics-based microfluidic platform provides multiple viscoelastic cell properties, and thus a more complete picture of a cell's mechanical state. Because it requires minimal sample preparation, utilizes a straightforward electronic measurement (in contrast to a high-speed camera), and takes advantage of standard soft lithography fabrication, the implementation of this platform is simple, accessible, and adaptable to downstream analysis. This platform's flexibility, utility, and sensitivity have provided unique mechanical information on a diverse range of cells, with the potential for many more applications in basic science and clinical diagnostics.

Presented here is a method to mechanically phenotype single cells using an electronics-based microfluidic platform called mechano-node-pore sensing (mechano-NPS). This platform maintains moderate throughput of 1-10 cells/s while measuring both the elastic and viscous biophysical properties of cells.

Mechano-Node-Pore Sensing: Eine schnelle, markierungsfreie Plattform für viskoelastische Multiparameter-Einzelzellmessungen

Cellular mechanical properties are involved in a wide variety of biological processes and diseases, ranging from stem cell differentiation to cancer ...

Assessing Murine Resistance Artery Function Using Pressure Myography

Pressure myograph systems are exquisitely useful in the functional assessment of small arteries, pressurized to a suitable transmural pressure. The near physiological condition achieved in pressure myography permits in-depth characterization of intrinsic responses to pharmacological and physiological stimuli, which can be extrapolated to the in vivo behavior of the vascular bed. Pressure myograph has several advantages over conventional wire myographs. For example, smaller resistance vessels can be studied at tightly controlled and physiologically relevant intraluminal pressures. Here, we study the ability of 3rd order mesenteric arteries (3-4 mm long), preconstricted with phenylephrine, to vaso-relax in response to acetylcholine. Mesenteric arteries are mounted on two cannulas connected to a pressurized and sealed system that is maintained at constant pressure of 60 mmHg. The lumen and outer diameter of the vessel are continuously recorded using a video camera, allowing real time quantification of the vasoconstriction and vasorelaxation in response to phenylephrine and acetylcholine, respectively.
	To demonstrate the applicability of pressure myography to study the etiology of cardiovascular disease, we assessed endothelium-dependent vascular function in a murine model of systemic hypertension. Mice deficient in the &alpha;1 subunit of soluble guanylate cyclase (sGC&alpha;1-/-) are hypertensive when on a 129S6 (S6) background (sGC&alpha;1-/-S6) but not when on a C57BL/6 (B6) background (sGC&alpha;1-/-B6). Using pressure myography, we demonstrate that sGC&alpha;1-deficiency results in impaired endothelium-dependent vasorelaxation. The vascular dysfunction is more pronounced in sGC&alpha;1-/-S6 than in sGC&alpha;1-/-B6 mice, likely contributing to the higher blood pressure in sGC&alpha;1-/-S6 than in sGC&alpha;1-/-B6 mice. 
	Pressure myography is a relatively simple, but sensitive and mechanistically useful technique that can be used to assess the effect of various stimuli on vascular contraction and relaxation, thereby augmenting our insight into the mechanisms underlying cardiovascular disease.

In pressure myography, an intact small segment of a vessel is mounted onto two small cannulas and pressurized to a suitable luminal pressure. Here, we describe the method to measure vasorelaxation response of the mouse 3rd order mesenteric arteries in c57 and sGC&alpha;1-/- mice using pressure myography.

Beurteilung Murine Widerstand Artery Funktion Mit Druck Myographie

Pressure myograph systems are  exquisitely useful in the functional assessment of small arteries, pressurized  to a suitable transmural pressure. The  ...

Standardizing a Non-Lethal Method for Characterizing the Reproductive Status and Larval Development of Freshwater Mussels (Bivalvia: Unionida)

Actively monitoring the timing, development, and reproductive patterns of endangered species is critical when managing for population recovery. Freshwater mussels are among the most imperiled organisms in the world, but information about early larval (glochidial) development and brooding periods is still lacking for many species. Previous studies have focused on the complex life history stage when female mussels are ready to parasitize host fish, but few studies have focused on the brooding period and timing of larval development. The protocol described here allows researchers to non-lethally evaluate the state of gravidity for female mussels. The results of this study show that this method does not affect a female mussel&rsquo;s ability to stay gravid or become gravid again after sampling has been performed. The advantage of this method may permit its use on federally threatened or endangered species or other populations of high conservation concern. This protocol can be adapted for use on both preserved or live individuals and was tested on a variety of mussel species. The database provided is a repository for a breadth of information on timing of reproductive habits and will facilitate future freshwater mussel research, conservation, and recovery efforts.

Standardizing a Non-Lethal Method for Characterizing the Reproductive Status and Larval Development of Freshwater Mussels Bivalvia: Unionida

Freshwater mussel conservation is dependent on monitoring reproductive patterns and processes of species. This study standardizes a non-lethal protocol for sampling gill contents, characterizing larval development, and providing a digital repository for data collected. This protocol-database package will be an important tool for mussel researchers in recovery of imperiled species.

Standardisierung einer nicht-tödlichen Methode zur Charakterisierung des Fortpflanzungsstatus und der Larval-Entwicklung von Süßwassermuscheln (Bivalvia: Unionida)

Actively monitoring the timing, development, and reproductive patterns of endangered species is critical when managing for population recovery. Freshwater ...