Accurate detection and quantification of seasonal abundance of American bullfrog (Lithobates catesbeianus) using ddPCR eDNA assays

AbstractThe invasive American bullfrog (Lithobates catesbeianus) imperils freshwater biodiversity worldwide. Effective management hinges on early detection of incipient invasions and subsequent rapid response, as established populations are extremely difficult to eradicate. Although environmental DNA (eDNA) detection methods provide a highly sensitive alternative to conventional surveillance techniques, extensive testing is imperative to generate reliable output. Here, we tested and compared the performance of two primer/probe assays to detect and quantify the abundance of bullfrogs in Western Europe in silico and in situ using digital droplet PCR (ddPCR). Although both assays proved to be equally target-specific and sensitive, one outperformed the other in ddPCR detection resolution (i.e., distinguishing groups of target-positive and target-negative droplets), and hence was selected for further analyses. Mesocosm experiments revealed that tadpole abundance and biomass explained 99% of the variation in eDNA concentration. Because per individual eDNA emission rates did not differ significantly among tadpoles and juveniles, and adults mostly reside out of the water, eDNA concentration can be used as an approximation of local bullfrog abundance in natural populations. Seasonal eDNA patterns in three colonized ponds showed parallel fluctuations in bullfrog eDNA concentration. An increase in eDNA concentration was detected in spring, followed by a strong peak coinciding with the breeding season (August, September or October), and continuously low eDNA concentrations during winter. With this study, we report the validation process required for appropriately implementing eDNA barcoding analyses in lentic systems. We demonstrate that this technique can serve as a solid and reliable tool to detect the early stages of bullfrog invasions and to quantify temporal changes in abundance that will be useful in coordinating large-scale bullfrog eradication programs and evaluating their efficiency.

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Accurate Detection and Quantification of Seasonal Abundance of American Bullfrog (Lithobates Catesbeianus) Using ddPCR eDNA Assays

10.21203/rs.3.rs-112558/v1 ◽

2020 ◽

Author(s):

Teun Everts ◽

David Halfmaerten ◽

Sabrina Neyrinck ◽

Nico De Regge ◽

Hans Jacquemyn ◽

...

Keyword(s):

Large Scale ◽

Natural Populations ◽

Late Summer ◽

Environmental Dna ◽

Seasonal Abundance ◽

Larval Abundance ◽

Emission Rates ◽

Freshwater Biodiversity ◽

Lithobates Catesbeianus ◽

American Bullfrog

Abstract The invasive American bullfrog (Lithobates catesbeianus) imperils freshwater biodiversity worldwide. Effective management includes rapid detection and response to incipient invasions, as established populations are extremely difficult to eradicate. Although environmental DNA (eDNA) approaches provide a highly sensitive alternative to conventional surveillance techniques, extensive testing is paramount to generate reliable output. Here, we tested and compared the performance of two primer/probe assays to detect and quantify the abundance of bullfrogs in silico and in situ using digital droplet PCR. Although both assays proved to be equally specific and sensitive, one outperformed the other in detection resolution (i.e. distinguishing target and non-target droplets), and hence was selected for further analyses. Mesocosm experiments using density series of larval and juvenile bullfrogs revealed that eDNA concentrations could explain 99% of the larval abundance and biomass. Per individual eDNA emission rates did not differ significantly among life stages, indicating that eDNA concentrations can be used as a reliable proxy to asses bullfrog abundance in natural populations. Seasonal eDNA patterns in three infested ponds showed parallel fluctuations in bullfrog eDNA concentrations. A peak in late summer (August, September or October), coinciding with the breeding season, was followed by continuously low eDNA concentrations in winter and spring. These findings demonstrate that eDNA analyses can be used as a solid and reliable tool to detect the early stages of bullfrog invasions and to quantify temporal changes in abundance that will be useful in coordinating and evaluating large-scale bullfrog eradication programs.

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Going the Distance

10.23943/princeton/9780691150772.001.0001 ◽

2020 ◽

Author(s):

Ron Harris

Keyword(s):

Large Scale ◽

Western Europe ◽

Family Firms ◽

Global Trade ◽

Long Distance ◽

Business Corporation ◽

Modern Economy ◽

Key Factor ◽

Silk Route ◽

Passive Investors

Before the seventeenth century, trade across Eurasia was mostly conducted in short segments along the Silk Route and Indian Ocean. Business was organized in family firms, merchant networks, and state-owned enterprises, and dominated by Chinese, Indian, and Arabic traders. However, around 1600 the first two joint-stock corporations, the English and Dutch East India Companies, were established. This book tells the story of overland and maritime trade without Europeans, of European Cape Route trade without corporations, and of how new, large-scale, and impersonal organizations arose in Europe to control long-distance trade for more than three centuries. It shows that by 1700, the scene and methods for global trade had dramatically changed: Dutch and English merchants shepherded goods directly from China and India to northwestern Europe. To understand this transformation, the book compares the organizational forms used in four major regions: China, India, the Middle East, and Western Europe. The English and Dutch were the last to leap into Eurasian trade, and they innovated in order to compete. They raised capital from passive investors through impersonal stock markets and their joint-stock corporations deployed more capital, ships, and agents to deliver goods from their origins to consumers. The book explores the history behind a cornerstone of the modern economy, and how this organizational revolution contributed to the formation of global trade and the creation of the business corporation as a key factor in Europe's economic rise.

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Towards Control of an Estuary

Water Science & Technology ◽

10.2166/wst.1987.0077 ◽

1987 ◽

Vol 19 (9) ◽

pp. 155-174

Author(s):

Henk L. F. Saeijs

Keyword(s):

Shallow Water ◽

Storm Surge ◽

Salt Marshes ◽

Large Scale ◽

Western Europe ◽

Oxygen Depletion ◽

Negative Effects ◽

Intertidal Flats ◽

Environmental Consequences ◽

Short Time

The Delta Project is in its final stage. In 1974 it was subjected to political reconsideration, but it is scheduled now for completion in 1987. The final touches are being put to the storm-surge barrier and two compartment dams that divide the Oosterschelde into three areas: one tidal, one with reduced tide, and one a freshwater lake. Compartmentalization will result in 13% of channels, 45% of intertidal flats and 59% of salt marshes being lost. There is a net gain of 7% of shallow-water areas. Human interventions with large scale impacts are not new in the Oosterschelde but the large scale and short time in which these interventions are taking place are, as is the creation of a controlled tidal system. This article focusses on the area with reduced tide and compares resent day and expected characteristics. In this reduced tidal part salt marshes will extend by 30–70%; intertidal flats will erode to a lower level and at their edges, and the area of shallow water will increase by 47%. Biomass production on the intertidal flats will decrease, with consequences for crustaceans, fishes and birds. The maximum number of waders counted on one day and the number of ‘bird-days' will decrease drastically, with negative effects for the wader populations of western Europe. The net area with a hard substratum in the reduced tidal part has more than doubled. Channels will become shallower. Detritus import will not change significantly. Stratification and oxygen depletion will be rare and local. The operation of the storm-surge barrier and the closure strategy chosen are very important for the ecosystem. Two optional closure strategies can be followed without any additional environmental consequences. It was essential to determine a clearly defined plan of action for the whole area, and to make land-use choices from the outset. How this was done is briefly described.

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The emerging roles of extracellular vesicles in ovarian cancer

Current Drug Metabolism ◽

10.2174/1389200221666201110155721 ◽

2020 ◽

Vol 21 ◽

Author(s):

Yin-xue Wang ◽

Yi-xiang Wang ◽

Yi-ke Li ◽

Shi-yan Tu ◽

Yi-qing Wang

Keyword(s):

Ovarian Cancer ◽

Extracellular Vesicles ◽

Large Scale ◽

Current Treatment ◽

Detection Methods ◽

Drug Resistant ◽

Apoptotic Bodies ◽

Biological Mechanisms ◽

Gynecological Malignancy ◽

Resistance To Chemotherapy

: Ovarian cancer (OC) is one of the deadliest gynecological malignancy. Epithelial ovarian cancer (EOC) is its most common form. OC has both a poor prognosis and a high mortality rate due to the difficulties of early diagnosis, the limitation of current treatment and resistance to chemotherapy. Extracellular vesicles is a heterogeneous group of cellderived submicron vesicles which can be detected in body fluids, and it can be classified into three main types including exosomes, micro-vesicles, and apoptotic bodies. Cancer cells can produce more EVs than healthy cells. Moreover, the contents of these EVs have been found distinct from each other. It has been considered that EVs shedding from tumor cells may be implicated in clinical applications. Such as a tool for tumor diagnosis, prognosis and potential treatment of certain cancers. In this review, we provide a brief description of EVs in diagnosis, prognosis, treatment, drug-resistant of OC. Cancer-related EVs show powerful influences on tumors by various biological mechanisms. However, the contents mentioned above remain in the laboratory stage and there is a lack of large-scale clinical trials, and the maturity of the purification and detection methods is a constraint. In addition, amplification of oncogenes on ecDNA is remarkably prevalent in cancer, it may be possible that ecDNA can be encapsulated in EVs and thus detected by us. In summary, much more research on EVs needs to be perform to reveal breakthroughs in OC and to accelerate the process of its application on clinic.

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Insectivorous songbirds as early indicators of future defoliation by spruce budworm

Landscape Ecology ◽

10.1007/s10980-021-01300-z ◽

2021 ◽

Author(s):

Marion Germain ◽

Daniel Kneeshaw ◽

Louis De Grandpré ◽

Mélanie Desrochers ◽

Patrick M. A. James ◽

...

Keyword(s):

Large Scale ◽

Spatial Scales ◽

Spruce Budworm ◽

Detection Methods ◽

Maximum Probability ◽

Point Count ◽

Probability Of Presence ◽

Time Lagged ◽

One Year ◽

Local Sampling

Abstract Context Although the spatiotemporal dynamics of spruce budworm outbreaks have been intensively studied, forecasting outbreaks remains challenging. During outbreaks, budworm-linked warblers (Tennessee, Cape May, and bay-breasted warbler) show a strong positive response to increases in spruce budworm, but little is known about the relative timing of these responses. Objectives We hypothesized that these warblers could be used as sentinels of future defoliation of budworm host trees. We examined the timing and magnitude of the relationships between defoliation by spruce budworm and changes in the probability of presence of warblers to determine whether they responded to budworm infestation before local defoliation being observed by standard detection methods. Methods We modelled this relationship using large-scale point count surveys of songbirds and maps of cumulative time-lagged defoliation over multiple spatial scales (2–30 km radius around sampling points) in Quebec, Canada. Results All three warbler species responded positively to defoliation at each spatial scale considered, but the timing of their response differed. Maximum probability of presence of Tennessee and Cape May warbler coincided with observations of local defoliation, or provided a one year warning, making them of little use to guide early interventions. In contrast, the probability of presence of bay-breasted warbler consistently increased 3–4 years before defoliation was detectable. Conclusions Early detection is a critical step in the management of spruce budworm outbreaks and rapid increases in the probability of presence of bay-breasted warbler could be used to identify future epicenters and target ground-based local sampling of spruce budworm.

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Uni-Temporal Multispectral Imagery for Burned Area Mapping with Deep Learning

Remote Sensing ◽

10.3390/rs13081509 ◽

2021 ◽

Vol 13 (8) ◽

pp. 1509

Author(s):

Xikun Hu ◽

Yifang Ban ◽

Andrea Nascetti

Keyword(s):

Deep Learning ◽

Large Scale ◽

Multiple Scales ◽

Detection Methods ◽

Burned Area ◽

Landsat 8 ◽

Multispectral Imagery ◽

Burned Areas ◽

Local Climate Zones ◽

Sentinel 2

Accurate burned area information is needed to assess the impacts of wildfires on people, communities, and natural ecosystems. Various burned area detection methods have been developed using satellite remote sensing measurements with wide coverage and frequent revisits. Our study aims to expound on the capability of deep learning (DL) models for automatically mapping burned areas from uni-temporal multispectral imagery. Specifically, several semantic segmentation network architectures, i.e., U-Net, HRNet, Fast-SCNN, and DeepLabv3+, and machine learning (ML) algorithms were applied to Sentinel-2 imagery and Landsat-8 imagery in three wildfire sites in two different local climate zones. The validation results show that the DL algorithms outperform the ML methods in two of the three cases with the compact burned scars, while ML methods seem to be more suitable for mapping dispersed burn in boreal forests. Using Sentinel-2 images, U-Net and HRNet exhibit comparatively identical performance with higher kappa (around 0.9) in one heterogeneous Mediterranean fire site in Greece; Fast-SCNN performs better than others with kappa over 0.79 in one compact boreal forest fire with various burn severity in Sweden. Furthermore, directly transferring the trained models to corresponding Landsat-8 data, HRNet dominates in the three test sites among DL models and can preserve the high accuracy. The results demonstrated that DL models can make full use of contextual information and capture spatial details in multiple scales from fire-sensitive spectral bands to map burned areas. Using only a post-fire image, the DL methods not only provide automatic, accurate, and bias-free large-scale mapping option with cross-sensor applicability, but also have potential to be used for onboard processing in the next Earth observation satellites.

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Metabolic, immunologic, and histopathologic responses on premetamorphic American bullfrog (Lithobates catesbeianus) following exposure to lithium and selenium

Environmental Pollution ◽

10.1016/j.envpol.2020.116086 ◽

2020 ◽

pp. 116086

Author(s):

Felipe Augusto Pinto-Vidal ◽

Cleoni dos Santos Carvalho ◽

Fábio Camargo Abdalla ◽

Letícia Ceschi-Bertoli ◽

Heidi Samantha Moraes Utsunomiya ◽

...

Keyword(s):

Lithobates Catesbeianus ◽

American Bullfrog

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Strategies to manage stream flow to benefit people and nature: a non-government conservation organisation's perspective

Water Science & Technology ◽

10.2166/wst.2004.0424 ◽

2004 ◽

Vol 49 (7) ◽

pp. 89-95

Author(s):

J. Pittock ◽

R. Holland

Keyword(s):

Stream Flow ◽

Large Scale ◽

River Basins ◽

River Basin Management ◽

Freshwater Biodiversity ◽

Flow Management ◽

Stream Flows ◽

Freshwater Management ◽

Increasing Demand ◽

The Impact

More than for any other biome, freshwater biodiversity is increasingly imperiled, particularly due to poor stream flow management and increasing demand for water diversions. The adoption by the world's governments of targets to extend water services to the poor and at the same time to conserve biodiversity increase the need to better direct investments in freshwater management. In this paper WWF draws on examples from its work to identify areas where investment can be focused to assure efficient water use and improve stream flow management, namely:• Prioritize and target those river basins and sub-catchments that are most critical for conservation of freshwater biodiversity to maintain stream flows;• Link strategic field, policy and market interventions at different scales in river basins to maximize the impact of interventions;• Implement the World Commission on Dams guidelines to minimize investment in large scale and costly infrastructure projects;• Apply market mechanisms and incentives for more sustainable production of the world's most water consuming crops;• Enhance statutory river basin management organizations to draw on their regulatory and financial powers;• Implement international agreements, such as the Convention on Wetlands;• Integrate environment and development policies.

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Recombinant polypeptide of Mycobacterium leprae as a potential tool for serological detection of leprosy

AMB Express ◽

10.1186/s13568-019-0928-9 ◽

2019 ◽

Vol 9 (1) ◽

Author(s):

Marcelo dos Santos Barbosa ◽

Iara Beatriz Andrade de Sousa ◽

Simone Simionatto ◽

Sibele Borsuk ◽

Silvana Beutinger Marchioro

Keyword(s):

Large Scale ◽

Mycobacterium Leprae ◽

Detection Methods ◽

Recombinant Polypeptide ◽

Cell Reactivity ◽

Tertiary Structures ◽

Leprosy Patients ◽

T Cell Reactivity ◽

Prevention Methods ◽

Scale Detection

AbstractCurrent prevention methods for the transmission of Mycobacterium leprae, the causative agent of leprosy, are inadequate as suggested by the rate of new leprosy cases reported. Simple large-scale detection methods for M. leprae infection are crucial for early detection of leprosy and disease control. The present study investigates the production and seroreactivity of a recombinant polypeptide composed of various M. leprae protein epitopes. The structural and physicochemical parameters of this construction were assessed using in silico tools. Parameters like subcellular localization, presence of signal peptide, primary, secondary, and tertiary structures, and 3D model were ascertained using several bioinformatics tools. The resultant purified recombinant polypeptide, designated rMLP15, is composed of 15 peptides from six selected M. leprae proteins (ML1358, ML2055, ML0885, ML1811, ML1812, and ML1214) that induce T cell reactivity in leprosy patients from different hyperendemic regions. Using rMLP15 as the antigen, sera from 24 positive patients and 14 healthy controls were evaluated for reactivity via ELISA. ELISA-rMLP15 was able to diagnose 79.17% of leprosy patients with a specificity of 92.86%. rMLP15 was also able to detect the multibacillary and paucibacillary patients in the same proportions, a desirable addition in the leprosy diagnosis. These results summarily indicate the utility of the recombinant protein rMLP15 in the diagnosis of leprosy and the future development of a viable screening test.

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PHENYLKETONURIA, AND GUTHRIE INHIBITION ASSAY SCREENING PROCEDURE

PEDIATRICS ◽

10.1542/peds.32.3.344 ◽

1963 ◽

Vol 32 (3) ◽

pp. 344-346

Keyword(s):

Public Health ◽

Large Scale ◽

Human Genetics ◽

Screening Program ◽

Genetic Diseases ◽

State Department ◽

The State ◽

Detection Methods ◽

Inhibition Assay ◽

Pilot Studies

Recommendations were made in view of the following facts: (1) the need for further information on the mechanisms involved in the phenotypic expressions of phenylketonuria; (2) the present lack of adequate data on the effectiveness of the Guthrie Inhibition Assay, in terms of number of cases which may be missed, factors making for positive determinations and providing other information on which to evaluate the appropriateness of the large-scale screening program proposed; (3) the undesirability of deploying inordinate resources in the evaluation of the Guthrie Inhibition Assay to the detriment of the needs of other areas of child health including phenylketonuria; (4) the indications that a multi-faceted approach to phenylketonuria would be productive, not only in resolving the problems involving this disorder but also as a model for the investigation of and application to the treatment of other genetic diseases; (5) the possibility that the Guthrie Inhibition Assay could be a useful tool in the early detection, treatment and investigation of phenylketonuria; and (6) the fact that other state health departments are participating in the Guthrie Field Trials, indicating that the California State Department of Public Health should apply its resources to a more intensive study of PKU and detection methods. The consultants made the following recommendations, through resolution, to the California State Department of Public Health. It was resolved that: 1. The State of California not be responsible at this time for initiating or recommending that the Guthrie procedure be accomplished on a state-wide basis in all newborn nurseries (one dissent). 2. The State of California initiate and coordinate the development of pilot studies in selected hospitals and medical centers throughout the State in the investigation of phenylketonuria, utilizing the Guthrie Inhibition Assay or other tests. 3. A scientific committee be appointed immediately as an advisory committee to the State Department of Public Health to develop recommendations for carrying out the suggested investigations. 4. A registry for phenylketonuria and other diseases (as listed in the recommendations by the Subcommittee on Human Genetics) be established within the framework of the State organization.

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