This work was funded, in part, by the Great Lakes Fishery Commission and the Annis Water Resources Institute. Use of trade, product, or firm names does not imply endorsement by the U. S. Government. This article is Contribution 1867 of the U. S. Geological Survey Great Lakes Science Center.

1. Laboratuvar Deney <ol><li> Av balık almak deney sırasında yırtıcı balık beslenecek. Tercihen bu yem balıkları alanında, dondurulmuş yakalanan ve yaklaşık -30 ° C&#39;de saklanmalıdır. Av balık için potansiyel bir kaynak olarak ticari balıkçılık faaliyetlerini düşünün. </li><li> Laboratuar tanklara yırtıcı balık tanıtın deney için kullanılacak. 15 yırtıcı balık kadar 870-L tanklarının her girmiştir ve 30 yırtıcı balık kadar önceki çalışmalarda 16,18 2.380-L tanklarının her girmiştir. </li><li> Seçilen av balık diyet yırtıcı balık alıştırıldı. Alıştırıldı sonra, yırtıcı balık deney başlamadan önce 1-3 ay boyunca bu diyet kalmalıdır. </li><li> Rastgele av balık partiden 10 ila 20 kompozit örnekleri seçerek yırtıcı balık örnekleri bir kenara koyun. Bileşik numunede av balık sayısı yırtıcı boyutuna bağlı olarak, 3-100 aralığı olabilirbalık. Her bileşik örnek dondurulmuş, Torbalı ve yaklaşık -30 ° C&#39;de saklanan iki olmalıdır. </li><li> Tankların her biri balık 30-50% ödün verilerek deneyi başlatın. <ol><li> , Balık euthanize büyük bir plastik kap içinde su 45 L Finquel 8 g karıştırılması ve daha sonra Finquel çözeltisi ile kap içinde balık yerleştirin. </li><li> Bir kez ötenazi, işleme zamanına kadar yaklaşık -30 ° C&#39;de bir torba, daha sonra çift çanta ve içine bir depo tankından kurban tüm balık yerleştirin. </li><li> Tankların her kalan her balık tartılır ve ağırlık kayıt; bir anestezik olasılıkla tartım yapmak için gerekli olacaktır. </li><li> , Balık anestezi büyük bir plastik kap içinde su 45 L Finquel 4.6 g karıştırın ve daha sonra Finquel çözeltisi ile kap içinde balık yerleştirin. </li><li> Balık tartı önce yürürlüğe girmesi anestezi için birkaç dakika bekleyin. </li></ol></li><li> Deney, her gün, bir çözülmeUygun av balık miktarı, kabaca 1 ila 5 gr ağırlığında parçalar halinde av balık kesti. Daha sonra, tankların her yerleştirilmesini av balık miktarı tartılır her bir tankın içine av balık parçaları damla ve yaklaşık 1 saat beslemek için yırtıcı balık sağlar. Daha sonra, tüm meyvelerin gıda kaldırma yaklaşık 20 dakika boyunca hava ile kuruması için gıda sağlar, ve daha sonra tankların her biri için meyvelerin gıda tartın. Tanka konulan gıda maddesi ve her gün tankların her biri için meyvelerin gıda maddesi kaydedin. NOT: Bir besleme döneminde her gün 18 sırasında tüketmek gibi temsilcisi deney için, göl alabalığı çok gıda olarak beslendi. Ancak, yırtıcı balık da sabit karneyle 16,19 yer olabilir. </li><li> Tankların her kalan yırtıcı tüm balık ödün verilerek deney iptal eder. , Balık euthanize büyük bir plastik kap içinde su 45 L Finquel 8 g karıştırılması ve daha sonra Finquel çözeltisi ile kap içinde balık yerleştirin. Tutanak tkurban her balık maddesinin ağırlığına. Güvenilir sonuçlar için, deney en az 130 gün süreyle, tercihen en az 100 gün boyunca devam gerekir. Işleme süresi kadar yaklaşık -30 ° C&#39;de bir torba, daha sonra çift çanta ve deposuna bir tanktan tüm balık yerleştirin. </li></ol> 2. Balık Homojenizasyon <ol><li> Yırtıcı balık ve / veya eritme için avlanan balıklar kompozit bir dizi seçin. Kompozitler kısmen çözülmeye bırakın. Her kompozit homojenize 0,5 saat 1 isteyebilir. </li><li> Uygun boyutlu karıştırıcılar kullanılarak, her bir kompozit homojenleştirin. Her bir bileşik için, temizlenmesi, aseton-durulanmış ve etiketlenmiş kavanoza homojenat (50 ila 100 g kadar) bir numuneyi. Daha sonra kavanoz kap ve işleme zamanına kadar yaklaşık -30 ° C&#39;de saklayın kavanoz. </li><li> Balık homojenize etmek için kullanılan tüm ekipman yıkayın ve daha sonra uygun örnekler arasında damıtılmış su ve metanol ile yıkayın. </li></ol> 3. Ekstraksiyon <ol><li> 20.0 gr tartılırbir 200 ml çanak içinde homojenize balık doku çözülmüş. </li><li> Sodyum sülfat, yaklaşık 40 g ekleyin ve bir spatula ile iyice karıştırın. </li><li> Ekstrak içindeki 20 ng / ml &#39;lik bir nihai konsantrasyon elde edilir konsantrasyonda konjenleyicileri 30, 61, 161, ve 166 içeren Spike&#39;ı taşıyıcı başak solüsyonu ekleyin. </li><li> Her 20 dakikada karıştırma sırasında, numune oda sıcaklığına soğumaya bırakın. </li><li> Numune, ekstraksiyon için hazırdır ve bu noktada kuru kum bir yoğunluğa ulaşmak için izin verin. </li><li> Teflon kaynatmak cips Soxhlet ve kondansatör içeren bir 500 ml&#39;lik şişeye Soxhlet&#39;le cihazı ayarlayın. </li><li> Bir kaba fritli disk alt veya kağıt yüksük ile cam takriben kuru balık karışımı ekleyin. </li><li> Örnek için kullanılan beher% 50 heksan ve% 50 diklorometan ile 150 ml ilave edilir ve bir spatula ile beher duvarlarını kazıma de karıştırılması. </li><li> Soxhlet boyunca ve döngüsüne bağlı şişeye ile Soxhlet üstüne çözücü geçişine izin veren ve onuŞişeye. </li><li> Tekrar 150 ml ile ikinci kez tekrarlayın. </li><li> Isıtma elemanı üzerine takılı şişesi ile Soxhlet yerleştirin ve kondansatörü takın. </li><li> Isıtma elemanı açın ve hafif bir kaynama noktasına getirmek çözücü, daha sonra 16 saat soğuk su kondansatörler beslenir emin en az ekstrakte edin. </li><li> Çözücü soğumaya bırakıldıktan sonra, numune şişe, su içermeyen kontrol edin. Su ihtiva eden şişelere, sodyum sülfat ilave edin, su, sodyum sülfat ile emilir kadar girdap. </li><li> Bir nitrojen örnek Yoğunlaştırıcısına veya sıcak su banyosu ile bir Kaderna Danimarka (KD) cam kurulumu kullanarak örnek Konsantre. </li><li> Numune en az 2 ml &#39;lik bir hacme gelinceye kadar buharlaştmn ve daha sonra, 5-ml&#39;lik volümetrik bir şişeye için kullanılan cam numunenin aktarmak için heksan kullanılarak küçük bir yıkama 5 ml&#39; lik bir son hacme getirmek için izin verin. </li><li> 10 ml hacimli ampullere aktarılır ve örnek bilgiler etiketleyin. </li></ol><ol><li> Aktive edilmiş silika jeli, 100 g konsantre sülfürik asit 44 g eklenerek asitleştirilmiş silika jel hazırlayın. </li><li> Altındaki cam yünü küçük bir tıkaç içeren bir küçük bir kromatografi kolonu içine asidifiye bir silika jel 10 g, ekleyin. </li><li> 10 ml heksan ile sütun ön temizleme işleminden sonra kolona numune ekstraktının 1 ml ilave edilir. </li><li> 20 ml heksan ile Kolonu akıtmak ve konik 20 ml&#39;lik cam tüp içinde toplar. </li><li> Bir azot akımı altında buharlaştırma azot (N Vap) cihazında cam tüp yerleştirilir ve sıcak su içine batırılır. </li><li> En az 1 ml buharlaştırılmakta, ancak kuruyana kadar değildir. </li><li> N Vap cihazından çıkarın ve heksan küçük yıkama maddeleri, 1-ml&#39;lik volümetrik şişeye transfer et. </li><li> 1.8 ml&#39;lik autosampler şişeye örnek bilgiler ile etiketlenmiş aktarın. </li><li> Şişenin içine iç standardın 4 ul Spike. Numune hemen analiz için hazır hale gelir. </li></ol> 5. AnalGaz Kromatografi Ysis - Kütle Spektrometre Negatif Kimyasal İyonizasyon kullanma <ol><li> Cihazı kalibre etmek için standartlar kullanın: standartlar iyi ayrılmış konjenerlerinin gruplarından oluşan karışımları mevcuttur. Karışımlar yaklaşık 1-5 Arochlors 1016, 1221, 1232, 1242, 1248, 1254 içinde bulunan konjenerlerinin tüm oluşur ve 1260 Karışım 1, çok katlı bir kalibrasyon karışımı şeklinde kullanılır, ve sistem doğrusallık en az hazırlanması ile doğrulanır 2 ve 100 ng / ml arasındaki konsantrasyonlarda beş kalibrasyon seviyeleri. Karmaları 2-5 Her kongener için tek nokta kalibrasyon olarak kullanılır. </li><li> Ile, reaktif gazı olarak taşıyıcı gaz (1 ml / dak) ve metan gibi hidrojen ile olumsuz kimyasal iyonizasyon modunda kütle spektrometresi sistemi - kromatografisi ayarlayın. </li><li> Ayrılması için 0.25 mikron film kalınlığında DB-XLB ile kaplanmış bir kaynaşmış-silis, kılcal kolon (0.25 mm iç çap × 60 m) kullanın. 26 ile, daha sonra 25 ° C / dakika ile 60 ila 212 ° C fırın sıcaklığı programı,0 ° 1 ° C / dk karıştırılmış, kloroform ve daha sonra 4 dakika son tutma tarihi ile birlikte, 4 ° C / dakika ile 280 ° C arasındadır. Enjektör ve transfer hattı sıcaklıkları 280 ° C&#39;ye ayarlanmış olmalıdır. Yarıksız enjeksiyon modu kullanılarak numunenin 1-2 ul enjekte edilir. </li><li> 13C-etiketli decachlorobiphenyl kullanılarak iç standart yöntemiyle, tüm standartlar ve numuneler analiz edin. </li><li> İkinci bir kaynak standart ve Aroclors 1242 ve 1260 çalıştırarak ilk kalibrasyon ile ilgili bir kontrol gerçekleştirin ve sonra bu onay prosedüründen gözlenen miktarlarda Aroclor Petkim&#39;de için tahmin değerlerini karşılaştırın. </li><li> Tüm numunelerin başlangıç ​​kalibrasyon prosedürü başarılı sağlandıktan sonra, tam bir analiz. Bir kalibrasyon ilk kalibrasyon kalibrasyon karışımların herhangi birini kullanarak, her on örnekleri kontrol çalıştırın. </li></ol> Net Trophic Transferi Verimliliği 6. Hesaplama <ol><li> Her kombinasyon o için, γ, net trofik transfer verimini hesaplayınaşağıdaki denklem kullanılarak f tankı ve PCB konjener: <img alt="Denklem 1" fo:content-width="2in" src="/files/ftp_upload/51496/51496eq1.jpg" /> [PCB f] Deneyin sonunda tankında yırtıcı balık ortalama PCB konjener konsantrasyonunu, W, F, deney sonunda tanktaki yırtıcı balık ortalama ağırlığı [PCB i] i Deneyin başlangıcında yırtıcı balık ortalama ağırlığı ve yutulur PCB kongener miktarı ağırlığına değinmektedir B deney başlangıcında tanktaki yırtıcı balık ortalama PCB konjener konsantrasyonudur PCB konjener deney sırasında tankı her göl alabalık, ortalama olarak, yutulur. </li><li> Tank dur de yırtıcı balık başına yemiş av balık ortalama miktarı (ağırlık) tarafından avlanan balıklar kompozit PCB kongener ortalama konsantrasyonunu çarparak yukarıdaki denklemde payda hesaplayınDeneyin tüm ders ing. </li></ol>

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C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determination+of+polychlorinated+biphenyl+congeners+in+human+milk+by+gas+chromatography+&#8211;+negative+chemical+ionization+mass+spectrometry+after+sample+clean-up+by+solid-phase+extraction.">Determination of polychlorinated biphenyl congeners in human milk by gas chromatography &#8211; negative chemical ionization mass spectrometry after sample clean-up by solid-phase extraction.</a> Journal of Chromatography B. 778 (1-2), 147-155 (2002).</li><li>Zorn, M. E., Gibbons, R. D., Sonzogni, W. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Weighted+least-squares+approach+to+calculating+limits+of+detection+and+quantification+by+modeling+variability+as+a+function+of+concentration.">Weighted least-squares approach to calculating limits of detection and quantification by modeling variability as a function of concentration.</a> Analytical Chemistry. 69 (15), 3069-3075 (1997).</li></ol>

Γ en doğru tahminleri için doğru deneyi Deney sırasında tank ve tank her meyvelerin gıda miktarı her yerleştirilen gıda miktarını hem de takip etmek mümkün olmalıdır. Bunu gerçekleştirmek için, deneyci tanklarından meyvelerin gıda kaldırmak ve doğru ağırlığını belirlemek mümkün olmalıdır. Aslında yırtıcı balıklar tarafından yenen gıda doğru izlemeye ek olarak, γ doğru tahmin de deney yeterli süresine bağlı olabilir. Yaygın olarak anılan laboratuar çalışmaları özellikl...

Of all of the factors affecting the rate at which fish accumulate contaminants, the efficiency with which fish retain contaminants from the food that they eat is one of the most important1-3. Risk assessment models have been developed to predict future risks to both people and wildlife eating contaminated fish under various scenarios of environmental contamination, and the reliability of these predictions critically depends on the accuracy of the estimates of the efficiency at which fish retain contaminants from their food4.
The efficiency with which the contaminant in the food ingested by the predator is transported through the gut wall is known as gross trophic transfer efficiency5. A portion of the quantity of the contaminant transported through the gut wall of the predator may eventually be lost through depuration and/or metabolic transformation. The efficiency with which the contaminant in the food ingested by the predator is retained by the predator, including any losses due to elimination and metabolic transformation, is known as net trophic transfer efficiency6.
Gross trophic transfer efficiency of organic contaminants to fish from their prey appears to vary with the contaminant&#8217;s chemical properties, including lipid affiliation as measured by the octanol-water partition coefficient, Kow3,7. According to an empirical relationship developed by Thomann3, gross trophic transfer efficiency is relatively high when log Kow is equal to a value between 5 and 6. Gross trophic transfer efficiency declines exponentially at a rate of 50% per unit of log Kow as log Kow increases from 6 to 10, according to the Thomann3 relationship.
Nevertheless, the gross and net trophic transfer efficiencies of polychlorinated biphenyl (PCB) congeners to fish from their prey do not appear to follow the Thomann3 relationship in most cases. Although the trophic transfer efficiencies of PCB congeners to lake whitefish (Coregonus clupeaformis) from its food followed the relationship proposed by Thomann8, trophic transfer efficiencies of PCB congeners were either just weakly related or not related at all to log Kow for Atlantic salmon (Salmo salar)9, rainbow trout (Oncorhynchus mykiss)10, coho salmon (Oncorhynchus kisutch)11, and northern pike (Esox lucius)11.
The overall goal of this study was to present a laboratory technique for estimating the net trophic transfer efficiencies of PCB congeners to a piscivorous fish from its prey. Lake trout (Salvelinus namaycush) was chosen as the piscivorous fish for our experiment because lake trout are relatively easy to maintain in laboratory tanks. Bloater (Coregonus hoyi) was selected as the prey fish to be fed to the lake trout because bloater is eaten by lake trout in its natural setting12. In addition, we determined whether the net trophic transfer efficiencies for lake trout estimated from our laboratory experiment followed the Thomann3 relationship. We also determined whether the degree of activity by the lake trout had a significant effect on net trophic transfer efficiency (&#947;) of the PCB congeners. Activity by lake trout in the Laurentian Great Lakes is believed to have recently increased because changes in the food webs have caused lake trout to allocate more energy toward searching for food13. Lake trout were forced to exercise in one set of tanks by subjecting these lake trout to relatively high flow rates, whereas the other lake trout were permitted to remain relatively inactive by subjecting them to relatively low flow rates. Finally, the specific details of our laboratory procedure that need to be carefully followed to ensure the highest degree of accuracy in the &#947; estimates and to make the laboratory results applicable to the field are discussed, as well as future directions for research building on our laboratory technique. Net trophic transfer efficiency can be estimated both in the laboratory and in the field, and advantages and disadvantages are associated with both approaches. Accuracy in the estimate of &#947; depends on the accuracy of the estimate of food consumption. The amount of food eaten by fish in the laboratory can be accurately determined when proper protocols are followed, whereas the amount of food eaten by fish in the field is typically estimated via bioenergetics modeling. Use of bioenergetics modeling to derive the amount of food eaten has the potential to introduce a substantial amount of uncertainty into the estimates of food consumption. Fish bioenergetics models have been shown to estimate food consumption with no detectable bias for the case of lake trout14,15, but considerable bias in bioenergetics model estimates of food consumption has been detected for the case of lake whitefish15,16. On the other hand, estimates of net trophic transfer efficiency estimated in the laboratory may not be applicable to the field due to a difference in feeding rates between the laboratory and the field17. Evidence from both the laboratory and the field suggest that feeding rate can influence &#947;14,17.
The methodology used in the present study for estimating &#947; in the laboratory is applicable to situations where the predator fish is fed prey fish, and the amount of prey fish eaten by the predator can be accurately tracked. To accomplish this, the experimenter must weigh all of the food before placement in the tank; and the experimenter must be able to remove all of the uneaten food from the tank, and then weigh the uneaten food. In addition, an adequate suite of mixers and blenders should be available to obtain a sufficient degree of homogenization of the samples of both predator and prey fish. Finally, the gas chromatography &#8211; mass spectrometry instrumentation used to determine the PCB congener concentrations must be capable of detecting and quantifying individual PCB congeners at relatively low concentrations.

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			<td height="21" style="height:21px;width:259px;">870-L fiberglass tanks</td>
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			<td height="21" style="height:21px;width:259px;">Sodium sulfate, anhydrous - granular</td>
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			<td style="width:87px;">Wilmad-Lab Glass</td>
			<td style="width:119px;">LG-7070-114</td>
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			<td style="width:119px;">7910000</td>
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			<td height="35" style="height:35px;width:259px;">Soxhlet extraction glassware (500 mL)</td>
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			<td style="width:119px;">&#160;LG-6900-104</td>
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			<td height="35" style="height:35px;width:259px;">Hexane</td>
			<td style="width:87px;">Burdick &#38; Jackson&#160;</td>
			<td style="width:119px;">Cat. 211-4</td>
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			<td height="35" style="height:35px;width:259px;">Dichloromethane</td>
			<td style="width:87px;">Burdick &#38; Jackson&#160;</td>
			<td style="width:119px;">Cat. 300-4</td>
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			<td height="21" style="height:21px;width:259px;">Silica gel</td>
			<td style="width:87px;">BDH</td>
			<td style="width:119px;">Cat. BDH9004-1KG</td>
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			<td height="35" style="height:35px;width:259px;">Labl Line 5000 mult-unit extraction heater</td>
			<td style="width:87px;">Lab Line Instruments</td>
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			<td height="35" style="height:35px;width:259px;">Agilent 5973 GC/MS with chemical ionization</td>
			<td style="width:87px;">Agilent</td>
			<td style="width:119px;">5973N</td>
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			<td height="52" style="height:52px;width:259px;">Internal standard solution&#160;</td>
			<td style="width:87px;">Cambridge Isotope Laboratories</td>
			<td style="width:119px;">EC-1410-1.2</td>
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			<td height="21" style="height:21px;width:259px;">PCB congener calibration standards</td>
			<td style="width:87px;">Accustandard</td>
			<td style="width:119px;">C-CSQ-SET</td>
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			<td height="21" style="height:21px;width:259px;">DB-XLB column (60m x 0.25mm, 0.25 micron)</td>
			<td style="width:87px;">Agilent/ J&#38;W</td>
			<td style="width:119px;">122-1262</td>
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laboratory estimation of net trophic transfer efficiencies of pcb congeners to lake trout (salvelinus namaycush) from its prey

Avlarını ikinci balıkçıl balık poliklorlanmış bifenil (PCB) konjenerlerinin net trofik aktarım etkinliği (γ) laboratuar tahmin etmek için bir teknik tarif edilmektedir. 135 gün laboratuar deney sırasında, biz sekiz laboratuar tanklarda muhafaza bloater göl alabalığı (Salvelinus namaycush) Lake Michigan yakalanmıştı (Coregonus hoyi) beslenir. Bloater göl alabalık için doğal bir av. Tankların dördünde, nispeten yüksek bir akış hızı, bir düşük akış hızı, diğer dört tank kullanılmıştır Ancak düşük göl alabalığı aktivitesi için izin göl alabalık nispeten yüksek aktivite için kullanılmıştır. Bir tank-ile-tank temelinde, deneyin her bir günü göl alabalık yenen gıda miktarı kaydedildi. Her bir göl alabalığı deneyin başlangıcında ve sonunda tartıldı. Sekiz tankların her birinden dört ila dokuz göl alabalığı Deneyin başlangıcında öldürülür ve tankların her kalan 10 göl alabalığı euthan edildiDeneyin sonunda ize. Bu deney sonunda göl alabalığı Deneyin başlangıcında göl alabalığı 75 PCB konjenerlerinin konsantrasyonu belirlenir ve bloaters olarak, deney sırasında göl alabalığı beslenir. Bu ölçümlere dayanarak, γ sekiz tankların her 75 PCB konjenerlerinin her biri için hesaplandı. Γ aktif ve inaktif hem göl alabalık için 75 PCB Petkim&#39;de her biri için hesaplanan idi. Deney sekiz tanklarda çoğaltılmış çünkü, yaklaşık standart hata γ tahmin edilebilir demek. Bu tür denemelerde sonuçları çevresel kirlenme, çeşitli senaryolar altında kirlenmiş balık yeme insanlar ve yaban hayatı gelecekteki riskini tahmin etmek için risk değerlendirme modelleri yararlıdır.

İlk göl alabalığı nihai göl alabalığı ağırlıkları 853 den 1.566 g (Tablo 1) değişmekteydi iken ortalama ağırlıkları 694 den 907 gr arasında değişmektedir ortalama olarak göl alabalığı, deney sırasında bir büyüme önemli miktarda gösterdi. 135 günlük deney sırasında bir göl alabalığı tarafından tüketilen gıdanın miktarı ortalama 641 den 2.649 gr arasında değişmektedir. Ortalama PCB konjener konsantrasyonları arasında değişen ortalama olarak PCB konjener ...

Watch this Scientific Journal Video about Laboratory Estimation of Net Trophic Transfer Efficiencies of PCB Congeners to Lake Trout Salvelinus namaycush from Its Prey at JoVE.com

Laboratory Estimation of Net Trophic Transfer Efficiencies of PCB Congeners to Lake Trout Salvelinus namaycush from Its Prey

Onların yırtıcı balıkçıl balık poliklorlanmış bifenil (PCB) Petkim&#39;de net trofik transfer verimi laboratuar tahmini için bir tekniği sunulmuştur. Alanına laboratuvar sonuçlarının uygulanabilirliğini en üst düzeye çıkarmak için, balıkçıl balık tipik alanda yenir av balık beslenen edilmelidir.

Göl Alabalık PCB kongenerinin Net Trofik Transferi Etkinliklerinin Laboratuvarı Tahmini (<em&gt; Salvelinus namaycush</em&gt;) Onun Prey dan

A technique for laboratory estimation of net trophic transfer efficiency (&#947;) of polychlorinated biphenyl (PCB) congeners to piscivorous fish from ...

laboratory-estimation-net-trophic-transfer-efficiencies-pcb-congeners

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JoVE Journal

Environment

Laboratory Estimation of Net Trophic Transfer Efficiencies of PCB Congeners to Lake Trout (Salvelinus namaycush) from Its Prey

10.9K Görüntüleme.  U. S. Geological Survey.  Onların yırtıcı balıkçıl balık poliklorlanmış bifenil (PCB) Petkim'de net trofik transfer verimi laboratuar tahmini için bir tekniği sunulmuştur. Alanına laboratuvar sonuçlarının uygulanabilirliğini en üst düzeye çıkarmak için, balıkçıl balık tipik alanda yenir av balık beslenen edilmelidir. 

Video: Laboratory Estimation of Net Trophic Transfer Efficiencies of PCB Congeners to Lake Trout Salvelinus namaycush from Its Prey

Laboratory-determined Phosphorus Flux from Lake Sediments as a Measure of Internal Phosphorus Loading

Eutrophication is a water quality issue in lakes worldwide, and there is a critical need to identify and control nutrient sources. Internal phosphorus (P) loading from lake sediments can account for a substantial portion of the total P load in eutrophic, and some mesotrophic, lakes. Laboratory determination of P release rates from sediment cores is one approach for determining the role of internal P loading and guiding management decisions. Two principal alternatives to experimental determination of sediment P release exist for estimating internal load: in situ measurements of changes in hypolimnetic P over time and P mass balance. The experimental approach using laboratory-based sediment incubations to quantify internal P load is a direct method, making it a valuable tool for lake management and restoration.
Laboratory incubations of sediment cores can help determine the relative importance of internal vs. external P loads, as well as be used to answer a variety of lake management and research questions. We illustrate the use of sediment core incubations to assess the effectiveness of an aluminum sulfate (alum) treatment for reducing sediment P release. Other research questions that can be investigated using this approach include the effects of sediment resuspension and bioturbation on P release.
The approach also has limitations. Assumptions must be made with respect to: extrapolating results from sediment cores to the entire lake; deciding over what time periods to measure nutrient release; and addressing possible core tube artifacts. A comprehensive dissolved oxygen monitoring strategy to assess temporal and spatial redox status in the lake provides greater confidence in annual P loads estimated from sediment core incubations.

Lake eutrophication is a water quality issue worldwide, making the need to identify and control nutrient sources critical. Laboratory determination of phosphorus release rates from sediment cores is a valuable approach for determining the role of internal phosphorus loading and guiding management decisions.

Göl tortulları Laboratuvar belirlenen Fosfor Flux İç Fosfor Yükleniyor bir tedbir olarak

Eutrophication is a water quality issue in lakes worldwide, and there is a critical need to identify and control nutrient sources. Internal phosphorus (P) ...

Çevre

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.

Bir Balık-besleme Laboratuvar biyodeneyinde Deniz Organizmaların Dokular Sekonder Metabolitlerin Antipredatory Aktivite değerlendirmek için

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

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.

Otomatik Jel Boyut Seçimi Çevre Su Örneklerinden hazırlanmıştır nesil Sıralama Kütüphaneler Kalitesi Geliştirmek için

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

Removal of Trace Elements by Cupric Oxide Nanoparticles from Uranium In Situ Recovery Bleed Water and Its Effect on Cell Viability

In situ recovery (ISR) is the predominant method of uranium extraction in the United States. During ISR, uranium is leached from an ore body and extracted through ion exchange. The resultant production bleed water (PBW) contains contaminants such as arsenic and other heavy metals. Samples of PBW from an active ISR uranium facility were treated with cupric oxide nanoparticles (CuO-NPs). CuO-NP treatment of PBW reduced priority contaminants, including arsenic, selenium, uranium, and vanadium. Untreated and CuO-NP treated PBW was used as the liquid component of the cell growth media and changes in viability were determined by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay in human embryonic kidney (HEK 293) and human hepatocellular carcinoma (Hep G2) cells. CuO-NP treatment was associated with improved HEK and HEP cell viability. Limitations of this method include dilution of the PBW by growth media components and during osmolality adjustment as well as necessary pH adjustment. This method is limited in its wider context due to dilution effects and changes in the pH of the PBW which is traditionally slightly acidic&#160;however; this method could have a broader use assessing CuO-NP treatment in more neutral waters.

Removal of Trace Elements by Cupric Oxide Nanoparticles from Uranium In Situ Recovery Bleed Water and Its Effect on Cell Viability

Production bleed water (PBW) was treated with cupric oxide nanoparticles (CuO-NPs) and cellular toxicity was assessed in cultured human cells. The goal of this protocol was to integrate the native environmental sample into a cell culture format assessing the changes in toxicity due to CuO-NP treatment.

Uranyum dan Bakır Oksit Nanopartiküller tarafından İz Elementlerin çıkarılması<em&gt; In Situ</em&gt; Kurtarma Bleed Su ve Hücre Canlılığı Üzerine Etkisi

In situ recovery (ISR) is the predominant method of uranium extraction in the United States. During ISR, uranium is leached from an ore body and extracted ...

Laboratory Simulation of an Iron(II)-rich Precambrian Marine Upwelling System to Explore the Growth of Photosynthetic Bacteria

A conventional concept for the deposition of some Precambrian Banded Iron Formations (BIF) proceeds on the assumption that ferrous iron [Fe(II)] upwelling from hydrothermal sources in the Precambrian ocean was oxidized by molecular oxygen [O2] produced by cyanobacteria. The oldest BIFs, deposited prior to the Great Oxidation Event (GOE) at about 2.4 billion years (Gy) ago, could have formed by direct oxidation of Fe(II) by anoxygenic photoferrotrophs under anoxic conditions. As a method for testing the geochemical and mineralogical patterns that develop under different biological scenarios, we designed a 40 cm long vertical flow-through column to simulate an anoxic Fe(II)-rich marine upwelling system representative of an ancient ocean on a lab scale. The cylinder was packed with a porous glass bead matrix to stabilize the geochemical gradients, and liquid samples for iron quantification could be taken throughout the water column. Dissolved oxygen was detected non-invasively via optodes from the outside. Results from biotic experiments that involved upwelling fluxes of Fe(II) from the bottom, a distinct light gradient from top, and cyanobacteria present in the water column, show clear evidence for the formation of Fe(III) mineral precipitates and development of a chemocline between Fe(II) and O2. This column allows us to test hypotheses for the formation of the BIFs by culturing cyanobacteria (and in the future photoferrotrophs) under simulated marine Precambrian conditions. Furthermore we hypothesize that our column concept allows for the simulation of various chemical and physical environments &#8212; including shallow marine or lacustrine sediments.

Laboratory Simulation of an IronII-rich Precambrian Marine Upwelling System to Explore the Growth of Photosynthetic Bacteria

We simulated a Precambrian ferruginous marine upwelling system in a lab-scale vertical flow-through column. The goal was to understand how geochemical profiles of O2 and Fe(II) evolve as cyanobacteria produce O2. The results show the establishment of a chemocline due to Fe(II) oxidation by photosynthetically produced O2.

Prekambriyen Deniz upwelling Sistemi Fotosentetik Bakteri Büyüme Keşfet bakımından zengin bir Demir (II) Laboratuar Simülasyonu

A conventional concept for the deposition of some Precambrian Banded Iron Formations (BIF) proceeds on the assumption that ferrous iron [Fe(II)] upwelling ...

Development of Metarhizium anisopliae as a Mycoinsecticide: From Isolation to Field Performance

A major concern when developing commercial mycoinsecticides is the kill speed compared to that of chemical insecticides. Therefore, isolation and screening for the selection of a fast-acting, highly virulent entomopathogenic fungus are important steps. Entomopathogenic fungi, such as Metarhizium, Beauveria, and Nomurea, which act by contact, are better suited than Bacillus thuringiensis or nucleopolyhedrosis virus (NPV), which must be ingested by the insect pest. In the present work, we isolated 68 Metarhizium strains from infected insects using a soil dilution and bait method. The isolates were identified by the amplification and sequencing of the ITS1-5.8S-ITS2 and 26S rDNA region. The most virulent strain of Metarhizium anisopliae was selected based on the median lethal concentration (LC50) and time (LT50) obtained in insect bioassays against III-instar larvae of Helicoverpa armigera. The mass production of spores by the selected strain was carried out with solid-state fermentation (SSF) using rice as a substrate for 14 days. Spores were extracted from the sporulated biomass using 0.1% tween-80, and different formulations of the spores were prepared. Field trials of the formulations for the control of an H. armigera infestation in pigeon peas were carried out by randomized block design. The infestation control levels obtained with oil and aqueous formulations (78.0% and 70.9%, respectively) were better than the 63.4% obtained with chemical pesticide.

Development of Metarhizium anisopliae as a Mycoinsecticide: From Isolation to Field Performance

Here, we report the different stages involved in the knowledge-based development of an effective mycoinsecticide, including the isolation, identification, screening, and selection of the "best-fit" entomopathogenic fungus, Metarhizium anisopliae, for the control of insect pests in agriculture.

Geliştirilmesi<em&gt; Metarhizium anisopliae</em&gt; Bir Mycoinsecticide Olarak: İzolasyondan Saha Performansına

A major concern when developing commercial mycoinsecticides is the kill speed compared to that of chemical insecticides. Therefore, isolation and ...

Procedures of Laboratory Fumigation for Pest Control with Nitric Oxide Gas

Nitric oxide (NO) is a newly discovered fumigant for postharvest pest control. This paper provides detailed protocols for conducting NO fumigation on fresh products and procedures for residue analysis and product quality evaluation. An airtight fumigation chamber containing fresh fruit and vegetables is first flushed with nitrogen (N2) to establish an ultralow oxygen (ULO) environment followed by injection of NO. The fumigation chamber is then kept at a low temperature of 2 - 5 &#176;C for a specified time period necessary to kill a target pest to complete a fumigation treatment. At the end of a fumigation treatment, the fumigation chamber is flushed with N2 to dilute NO prior to opening the chamber to ambient air to prevent the reaction between NO and O2, which produces NO2 and may damage delicate fresh products. At different times after NO fumigation, NO2 in headspace and nitrate and nitrite in liquid samples were measured as residues. Product quality was evaluated after 2 weeks of post-treatment cold storage to determine effects of NO fumigation on product quality. Keeping&#160;O2 from reacting with NO is critical to NO fumigation and is an important part of the protocols. Measuring NO levels is challenging and a practical solution is provided. Possible protocol modifications are also suggested for measuring NO levels in the fumigation chambers as well as residues. NO fumigation has the potential to be a practical alternative to methyl bromide fumigation for postharvest pest control on fresh and stored products. This publication is intended to assist other researchers in conducting NO fumigation research for postharvest pest control and accelerating the development of NO fumigation for practical applications.

This paper describes nitric oxide (NO) fumigation protocols for postharvest pest control. Fumigation chambers are flushed with nitrogen (N2) to establish ultralow oxygen conditions before NO is injected. At the end, chambers are flushed with N2 to dilute NO before exposing products to ambient air to prevent exposure to NO2.

Laboratuvar İlaçlama haşere kontrolü ile nitrik oksit gaz için prosedürleri

Nitric oxide (NO) is a newly discovered fumigant for postharvest pest control. This paper provides detailed protocols for conducting NO fumigation on ...

Adherence of Bacteria to Plant Surfaces Measured in the Laboratory

This manuscript describes a method to measure bacterial binding to axenic plant surfaces in the light microscope and through the use of viable cell counts. Plant materials used include roots, sprouts, leaves, and cut fruits. The methods described are inexpensive, easy, and suitable for small sample sizes. Binding is measured in the laboratory and a variety of incubation media and conditions can be used. The effect of inhibitors can be determined. Situations that promote and inhibit binding can also be assessed. In some cases it is possible to distinguish whether various conditions alter binding primarily due to their effects on the plant or on the bacteria.

An easy method for measuring and characterizing bacterial adhesion to plants, particularly roots and sprouts, is described in this article.

Laboratuvarda ölçmek yüzeyler bitki bakterilerin bağlılık

This manuscript describes a method to measure bacterial binding to axenic plant surfaces in the light microscope and through the use of viable cell ...

Ecosystem Fabrication (EcoFAB) Protocols for The Construction of Laboratory Ecosystems Designed to Study Plant-microbe Interactions

Beneficial plant-microbe interactions offer a sustainable biological solution with the potential to boost low-input food and bioenergy production. A better mechanistic understanding of these complex plant-microbe interactions will be crucial to improving plant production as well as performing basic ecological studies investigating plant-soil-microbe interactions. Here, a detailed description for ecosystem fabrication is presented, using widely available 3D printing technologies, to create controlled laboratory habitats (EcoFABs) for mechanistic studies of plant-microbe interactions within specific environmental conditions. Two sizes of EcoFABs are described that are suited for the investigation of microbial interactions with various plant species, including Arabidopsis thaliana, Brachypodium distachyon, and Panicum virgatum. These flow-through devices allow for controlled manipulation and sampling of root microbiomes, root chemistry as well as imaging of root morphology and microbial localization. This protocol includes the details for maintaining sterile conditions inside EcoFABs and mounting independent LED light systems onto EcoFABs. Detailed methods for addition of different forms of media, including soils, sand, and liquid growth media coupled to the characterization of these systems using imaging and metabolomics are described. Together, these systems enable dynamic and detailed investigation of plant and plant-microbial consortia including the manipulation of microbiome composition (including mutants), the monitoring of plant growth, root morphology, exudate composition, and microbial localization under controlled environmental conditions. We anticipate that these detailed protocols will serve as an important starting point for other researchers, ideally helping create standardized experimental systems for investigating plant-microbe interactions.

Ecosystem Fabrication EcoFAB Protocols for The Construction of Laboratory Ecosystems Designed to Study Plant-microbe Interactions

This article describes detailed protocols for ecosystem fabrication of devices (EcoFABs) that enable the studies of plants and plant-microbe interactions in highly controlled laboratory conditions.

Ekosistem imalat (EcoFAB) protokolleri laboratuvar ekosistemlerinin bitki-mikrop etkileşimleri çalışma için tasarlanmış inşası için

Beneficial plant-microbe interactions offer a sustainable biological solution with the potential to boost low-input food and bioenergy production. A ...

Laboratory and Field Protocol for Estimating Sheet Erosion Rates from Dendrogeomorphology

Sheet erosion is among the crucial drivers of soil degradation. Erosion is controlled by environmental factors and human activities, which often lead to severe environmental impacts. The understanding of sheet erosion is, consequently, a worldwide issue with implications for both environment and economies. However, the knowledge on how erosion evolves in space and time is still limited, as well as its effects on the environment. Below, we explain a new dendrogeomorphological protocol for deriving eroded soil thickness (Ex) by acquiring accurate microtopographic data using both terrestrial laser scanning (TLS) and microtopographic profile gauges. Additionally, standard dendrogeomorphic procedures, dependent on anatomical variations in root rings, are utilized to establish the timing of exposure. Both TLS and microtopographic profile gauges are used to obtain ground surface pro&#64257;les, from which Ex is estimated after the threshold distance (TD) is determined, i.e., the distance between the root and the sediment knickpoint, which allows de&#64257;ning the lowering of the ground surface caused by sheet erosion. For each profile, we measured the height between the topside of the root and a virtual plane tangential to the ground surface. In this way, we intended to avoid small-scale impacts of soil deformation, which may be due to pressures exerted by the root system, or by the arrangement of exposed roots. This may provoke small amounts of soil sedimentation or erosion depending on how they physically affect the surface runoff. We demonstrate that an adequate microtopographic characterization of exposed roots and their associated ground surface is very valuable to obtain accurate erosion rates. This finding could be utilized to develop the best management practices designed to eventually halt or perhaps, at least, lessen soil erosion, so that more sustainable management policies can be put into practice.

Characterizing erosion from dendrogeomorphology has usually focused on accurately finding the starting time of root exposure, by examining macroscopic or cell level changes caused by exposure. Here, we offer a detailed description of different novel techniques to obtain more precise erosion rates from highly accurate microtopographic data.

Laboratuvar ve levha erozyon oranları üzerinden Dendrogeomorphology tahmin etmek için alan Protokolü

Sheet erosion is among the crucial drivers of soil degradation. Erosion is controlled by environmental factors and human activities, which often lead to ...