scholarly journals Interlaboratory Validation of Toxicity Testing Using the Duckweed Lemna minor Root-Regrowth Test

Biology ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 37
Author(s):  
Jihae Park ◽  
Eun-Jin Yoo ◽  
Kisik Shin ◽  
Stephen Depuydt ◽  
Wei Li ◽  
...  
Keyword(s):  
Natural Waters ◽  
Lemna Minor ◽  
Toxicity Testing ◽  
Test Method ◽  
Rapid Screening ◽  
The Novel ◽  
Root Regrowth ◽  
Interlaboratory Validation ◽  
Validity Criteria ◽  
Slow Moving

The common duckweed (Lemna minor), a freshwater monocot that floats on the surfaces of slow-moving streams and ponds, is commonly used in toxicity testing. The novel Lemna root- regrowth test is a toxicity test performed in replicate test vessels (24-well plates), each containing 3 mL test solution and a 2–3 frond colony. Prior to exposure, roots are excised from the plant, and newly developed roots are measured after 3 days of regrowth. Compared to the three internationally standardized methods, this bioassay is faster (72 h), simpler, more convenient (requiring only a 3-mL) and cheaper. The sensitivity of root regrowth to 3,5-dichlorophenol was statistically the same as using the conventional ISO test method. The results of interlaboratory comparison tests conducted by 10 international institutes showed 21.3% repeatability and 27.2% reproducibility for CuSO4 and 21.28% repeatability and 18.6% reproducibility for wastewater. These validity criteria are well within the generally accepted levels of <30% to 40%, confirming that this test method is acceptable as a standardized biological test and can be used as a regulatory tool. The Lemna root regrowth test complements the lengthier conventional protocols and is suitable for rapid screening of wastewater and priority substances spikes in natural waters.

Interlaboratory Validation of a Real-Time PCR 24-Hour Rapid Method for Detection of Salmonella in Foods

2009 ◽  
Vol 72 (5) ◽  
pp. 945-951 ◽  
Author(s):  
CHORNG-MING CHENG ◽  
KHANH T. VAN ◽  
WEN LIN ◽  
RICHARD M. RUBY
Keyword(s):  
Real Time ◽  
Screening Method ◽  
Rapid Screening ◽  
Selective Enrichment ◽  
Manual Method ◽  
Qpcr Method ◽  
Peptone Water ◽  
Interlaboratory Validation ◽  
Chili Powder ◽  
The One

The efficacy of a 24-h Salmonella real-time, or quantitative, PCR (qPCR) detection method was assessed through a collaborative effort involving eight Federal and state laboratories. Eleven foods including mashed potatoes, soft cheese, chili powder, chocolate, eggs, sprouts, apple juice, fish, shrimp, ground beef, and ground chicken were tested. For each food, seven blind samples were distributed to each participant for testing. These included six samples equivalently inoculated with 1 to 5 CFU/25 g of various serotypes of Salmonella (Gaminara, Weltevreden, Heidelberg, Senftenberg, Enteritidis, Newport, Typhimurium, and Kentucky for each food) and 10 to 50 CFU/25 g of the competitor Enterobacter cloacae. The seventh sample was inoculated with 10 to 50 CFU/25 g of the competitor, E. cloacae, only. These samples were tested for Salmonella by using four methods in parallel: (i) 24-h qPCR method detecting Salmonella from modified buffered peptone water enrichment medium; (ii) 48-h qPCR method detecting Salmonella from a secondary selective enrichment broth; (iii) modified Bacteriological Analytical Manual method; and (iv) VIDAS, an immunoassay system. The results of the statistical analysis showed there was no significant (P ≥ 0.05) difference between either of the qPCR methods and the modified Bacteriological Analytical Manual method for 10 of 11 foods. For the one exception, sprouts, detection by qPCR required 48 h. Both qPCR methods showed a detection limit of 0.08 to 0.2 CFU/g. These results provide a solid basis for using this 24-h qPCR rapid screening method to detect Salmonella in foods.

scholarly journals Disposable silicon-based all-in-one micro-qPCR for rapid on-site detection of pathogens

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Estefania Nunez-Bajo ◽  
Alexander Silva Pinto Collins ◽  
Michael Kasimatis ◽  
Yasin Cotur ◽  
Tarek Asfour ◽  
...  
Keyword(s):  
Real Time ◽  
Limit Of Detection ◽  
Low Cost ◽  
High Specificity ◽  
Rapid Screening ◽  
Quantitative Detection ◽  
The Novel ◽  
Novel Coronavirus ◽  
Silicon Based ◽  
Specific Sequences

AbstractRapid screening and low-cost diagnosis play a crucial role in choosing the correct course of intervention when dealing with highly infectious pathogens. This is especially important if the disease-causing agent has no effective treatment, such as the novel coronavirus SARS-CoV-2, and shows no or similar symptoms to other common infections. Here, we report a disposable silicon-based integrated Point-of-Need transducer (TriSilix) for real-time quantitative detection of pathogen-specific sequences of nucleic acids. TriSilix can be produced at wafer-scale in a standard laboratory (37 chips of 10 × 10 × 0.65 mm in size can be produced in 7 h, costing ~0.35 USD per device). We are able to quantitatively detect a 563 bp fragment of genomic DNA of Mycobacterium avium subspecies paratuberculosis through real-time PCR with a limit-of-detection of 20 fg, equivalent to a single bacterium, at the 35th cycle. Using TriSilix, we also detect the cDNA from SARS-CoV-2 (1 pg) with high specificity against SARS-CoV (2003).

scholarly journals Growth of duckweed upon exposure to aluminum and atrazine in the laboratory conditions

2018 ◽  
Vol 9 (2) ◽  
pp. 106-111
Author(s):  
Thi My Chi Vo ◽  
Minh Phap Dao ◽  
Thanh Son Dao
Keyword(s):  
Growth Rate ◽  
Aquatic Ecosystems ◽  
Natural Waters ◽  
Lemna Minor ◽  
Viet Nam ◽  
Combined Effects ◽  
Ecological Health ◽  
Negative Effects ◽  
Antagonistic Effects ◽  
Guideline Values

The trace metals and pesticides are commonly found in surface water receiving industrial and agricultural effluents. However, the potential negative effects of these compounds on aquatic ecosystems have not been deeply studied. Hence, the aim of this study is to assess the single and combined effects of aluminum (Al) and atrazine on the development and growth rate of duckweed, Lemna minor L. The single exposures were implemented with either Al or atrazine at the concentration of 5, 50 and 500 µg L-1 and a binary exposure was conducted with 50 µg L-1 of Al and 5 µg L-1 of atrazine for two weeks. The results revealed that both Al and atrazine at the concentration of 500 µg L-1 strongly inhibited the development and growth rate of the duckweed. On the contrary, the mixture of Al and atrazine showed antagonistic effects on the plant. To our knowledge, this is the first report on the combined effects of these two contaminants on the duckweed. Therefore, our results could be useful for environmental managers in setting up and adjusting the safe guideline values in Vietnam for Al and atrazine in natural waters in term of ecological health protection. Kim loại nặng và thuốc trừ sâu thường được tìm thấy trong các nguồn nước mặt, nơi tiếp nhận nước thải công nghiệp và nông nghiệp. Tuy nhiên, những ảnh hưởng tiềm tàng mang tính tiêu cực của những hợp chất này đối với hệ sinh thái thủy vực chưa được nghiên cứu đầy đủ. Do đó, mục tiêu của nghiên cứu này nhằm đánh giá những ảnh hưởng riêng lẻ và kết hợp của nhôm (Al) và atrazine lên sự phát triển và tốc độ sinh trưởng của bèo tấm, Lemma minor L. Sự phơi nhiễm riêng lẻ với Al hoặc atrazine được thực hiện ở các nồng độ 5, 50 và 500 µg L-1, trong khi đó, quá trình phơi nhiễm kết hợp được tiến hành với Al tại nồng độ 50 µg L-1 và atrazine tại nồng độ 5 µg L-1 trong hai tuần. Kết quả cho thấy cả Al và atrazine ở nồng độ phơi nhiễm 500 µg L-1 kìm hãm mạnh mẽ sự phát triển và tốc độ sinh trưởng của bèo tấm. Ngược lại, sự kết hợp Al và atrazine dẫn kết tác động triệt tiêu trên bèo tấm. Theo sự hiểu biết của chúng tôi, đây là ghi nhận đầu tiên về những ảnh hưởng kết hợp của hai chất gây ô nhiễm này lên bèo tấm. Vì vậy, những kết quả này có thể hữu ích cho các nhà quản lý môi trường tại Việt Nam trong việc thiết lập và điều chỉnh các giá trị an toàn đối với Al và Atrazie trong môi trường nước tự nhiên về khía cạnh bảo vệ sức khỏe sinh thái.  

Effect of Azadirachta indica A. Juss var indica, Nicotiana tabacum L., and Derris elliptica (Roxb.) on Growth of Duckweed

2014 ◽  
Vol 1060 ◽  
pp. 211-214
Author(s):  
Patamawan Phuagphong ◽  
Srisombat Nawanopparatsakul ◽  
Nudchanart Kitcharoen
Keyword(s):  
Nicotiana Tabacum ◽  
Azadirachta Indica ◽  
Lemna Minor ◽  
Cost Effective ◽  
Inhibitory Effect ◽  
Test Method ◽  
Biological Weed Control ◽  
Inhibitory Effects ◽  
Natural Herbicides ◽  
Extraction Solvents

The study was designed to evaluate the inhibitory effects of selected herbs on plant growth. Three insecticides containing plants (leaf of Azadirachta indica A. Juss var indica (AI), Nicotiana tabacum L. (NT), and root of Derris elliptica (Roxb.) (DE) were selected for various solvent extractions. Five extraction solvents: methanol, hexane, dichloromethane, butanol and aqueous were used in this study. The test method was lemna phytotoxicity assay which measured the inhibitory effect on duckweed, Lemna minor growth. This toxicity test proved to be a practical bioassay method because this method is simple, sensitive and cost effective. Butanol extracts of AI were shown to have more inhibition activity on duckweed growth than NT (% inhibition growth rate is 66.08, 27.08 respectively). Butanol extracts of AI had inhibitory effect (EC10) of 40.87 μg/ ml while dichloromethane extracts had EC10 of 131.72 μg/ ml. It could therefore be concluded that butanol extracts of AI showed the greatest inhibitory effects. The results from this study suggest that butanol extracts of AI were the most promising candidates for biological weed control and might be used as potential natural herbicides or as alternatives for the reduction of chemical herbicides. The study is worthy of further investigation since this could provide potential bioherbicide and may lead to the discovery of new effective and applicable bioherbicide.

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