Anja Schlierf

Mrs. Anja Schlierf

orcid

Research Focus & Metrics

Academic Career Length

6Years (2021-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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8 June 2022 in Diagnostics
Verified
Journal Article
Open access
PDF file
JDJonas Dohmen
Jonas Dohmen
ASAlexander Semaan
Alexander Semaan
MKMakbule Kobilay
Makbule Kobilay
MZMartin Zaleski
Martin Zaleski
VBVittorio Branchi
Vittorio Branchi
Stefan HoldenriederStefan Holdenrieder
Stefan Holdenrieder
Background: Despite the significance of colonoscopy for early diagnosis of colorectal adenocarcinoma (CRC), population-wide screening remains challenging, mainly because of low acceptance rates. Herein, exosomal (exo-miR) and free circulating microRNA (c-miR) may be used as liquid biopsies in CRC to identify individuals at risk. Direct comparison of both compartments has shown inconclusive results, which is why we directly compared a panel of 10 microRNAs in this entity. Methods: Exo-miR and c-miR levels were measured using real-time quantitative PCR after isolation from serum specimens in a cohort of 69 patients. Furthermore, results were compared to established tumor markers CEA and CA 19-9. Results: Direct comparison of exo- and c-miR biopsy results showed significantly higher microRNA levels in the exosomal compartment (p < 0.001). Exo-Let7, exo-miR-16 and exo-miR-23 significantly differed between CRC and healthy controls (all p < 0.05), while no c-miR showed this potential. Sensitivity and specificity can be further enhanced using combinations of multiple exosomal miRNAs. Conclusions: Exosomal microRNA should be considered as a promising biomarker in CRC for future studies. Nonetheless, results may show interference with common comorbidities, which must be taken into account in future studies.

12 April 2022 in Foods
Verified
Journal Article
Open access
PDF file
SDStefanie Dobrovolny
Stefanie Dobrovolny
SUSteffen Uhlig
Steffen Uhlig
KFKirstin Frost
Kirstin Frost
ASAnja Schlierf
Anja Schlierf
KNKapil Nichani
Kapil Nichani
RHRupert Hochegger
Rupert Hochegger
Meat species authentication in food is most commonly based on the detection of genetic variations. Official food control laboratories frequently apply single and multiplex real-time polymerase chain reaction (PCR) assays and/or DNA arrays. However, in the near future, DNA metabarcoding, the generation of PCR products for DNA barcodes, followed by massively parallel sequencing by next generation sequencing (NGS) technologies, could be an attractive alternative. DNA metabarcoding is superior to well-established methodologies since it allows simultaneous identification of a wide variety of species not only in individual foodstuffs but even in complex mixtures. We have recently published a DNA metabarcoding assay for the identification and differentiation of 15 mammalian species and six poultry species. With the aim to harmonize analytical methods for food authentication across EU Member States, the DNA metabarcoding assay has been tested in an interlaboratory ring trial including 15 laboratories. Each laboratory analyzed 16 anonymously labelled samples (eight samples, two subsamples each), comprising six DNA extract mixtures, one DNA extract from a model sausage, and one DNA extract from maize (negative control). Evaluation of data on repeatability, reproducibility, robustness, and measurement uncertainty indicated that the DNA metabarcoding method is applicable for meat species authentication in routine analysis.

23 July 2021 in Journal of Veterinary Diagnostic Investigation
Verified
Journal Article
Open access
PDF file
KDKaiping Deng
Kaiping Deng
SUSteffen Uhlig
Steffen Uhlig
HIHon S. Ip
Hon S. Ip
MKMary Lea Killian
Mary Lea Killian
LGLaura B Goodman
Laura B Goodman
RRRenate Reimschuessel
Renate Reimschuessel
The continued search for intermediate hosts and potential reservoirs for SARS-CoV2 makes it clear that animal surveillance is critical in outbreak response and prevention. Real-time RT-PCR assays for SARS-CoV2 detection can easily be adapted to different host species. U.S. veterinary diagnostic laboratories have used the CDC assays or other national reference laboratory methods to test animal samples. However, these methods have only been evaluated using internal validation protocols. To help the laboratories evaluate their SARS-CoV2 test methods, an interlaboratory comparison (ILC) was performed in collaboration with multiple organizations. Forty-four sets of 19 blind-coded RNA samples in Tris-EDTA (TE) buffer or PrimeStore transport medium were shipped to 42 laboratories. Results were analyzed according to the principles of the International Organization for Standardization (ISO) 16140-2:2016 standard. Qualitative assessment of PrimeStore samples revealed that, in approximately two-thirds of the laboratories, the limit of detection with a probability of 0.95 (LOD95) for detecting the RNA was ≤20 copies per PCR reaction, close to the theoretical LOD of 3 copies per reaction. This level of sensitivity is not expected in clinical samples because of additional factors, such as sample collection, transport, and extraction of RNA from the clinical matrix. Quantitative assessment of Ct values indicated that reproducibility standard deviations for testing the RNA with assays reported as N1 were slightly lower than those for N2, and they were higher for the RNA in PrimeStore medium than those in TE buffer. Analyst experience and the use of either a singleplex or multiplex PCR also affected the quantitative ILC test results.

18 August 2022 in Journal of Veterinary Diagnostic Investigation
Verified
Journal Article
Open access
KDKaiping Deng
Kaiping Deng
SUSteffen Uhlig
Steffen Uhlig
LGLaura B Goodman
Laura B Goodman
HIHon S. Ip
Hon S. Ip
MKMary Lea Killian
Mary Lea Killian
GTGregory H. Tyson
Gregory H. Tyson
The COVID-19 pandemic presents a continued public health challenge. Veterinary diagnostic laboratories in the United States use RT-rtPCR for animal testing, and many laboratories are certified for testing human samples; hence, ensuring that laboratories have sensitive and specific SARS-CoV2 testing methods is a critical component of the pandemic response. In 2020, the FDA Veterinary Laboratory Investigation and Response Network (Vet-LIRN) led an interlaboratory comparison (ILC1) to help laboratories evaluate their existing RT-rtPCR methods for detecting SARS-CoV2. All participating laboratories were able to detect the viral RNA spiked in buffer and PrimeStore molecular transport medium (MTM). With ILC2, Vet-LIRN extended ILC1 by evaluating analytical sensitivity and specificity of the methods used by participating laboratories to detect 3 SARS-CoV2 variants (B.1; B.1.1.7 [Alpha]; B.1.351 [Beta]) at various copy levels. We analyzed 57 sets of results from 45 laboratories qualitatively and quantitatively according to the principles of ISO 16140-2:2016. More than 95% of analysts detected the SARS-CoV2 RNA in MTM at ≥500 copies for all 3 variants. In addition, for nucleocapsid markers N1 and N2, 81% and 92% of the analysts detected ≤20 copies in the assays, respectively. The analytical specificity of the evaluated methods was >99%. Participating laboratories were able to assess their current method performance, identify possible limitations, and recognize method strengths as part of a continuous learning environment to support the critical need for the reliable diagnosis of COVID-19 in potentially infected animals and humans.

12 April 2025 in Polymers
Verified
Journal Article
Open access
PDF file
MSMarius Stieglitz
Marius Stieglitz
SASonja Adomeit
Sonja Adomeit
Marisa MüllerMarisa Müller
Marisa Müller
KHKarina Hettwer
Karina Hettwer
ASAnja Schlierf
Anja Schlierf
LLLisa Leuchtenberger
Lisa Leuchtenberger
This study investigates the potential of data-driven modeling to monitor and predict mechanical properties of extruded film using recyclates. The first step is to investigate whether a process parameter can indicate the input material quality of the material, which can vary significantly due to the use of recyclate. The die pressure was shown to be a key indicator due to its strong correlation with viscosity and material degradation. The second step is to explore the ability of machine learning models—Generalized Additive Models, Linear Regression, and Random Forest—to predict film tensile strength and modulus based on extrusion process and material parameters. The results demonstrate that including Melt Flow Rate and shear viscosity in addition to pressure and feedstock type (Virgin, PIR, and PCR) significantly improves model accuracy, with Generalized Additive Models achieving the highest R2 of 85.7% for tensile strength prediction. Additionally, the observed variability between different recyclate streams highlights the need for a more detailed classification of recyclates to better predict and optimize the mechanical performance of the film. While data-driven approaches for predicting properties show promise, their effectiveness remains limited by data availability and feedstock variability. Expanding datasets and improving process stability will be critical to refining predictive models for industrial application.

6 May 2026 in Journal of Food Protection
Verified
Journal Article
Open access
MMMegan R. Miller
Megan R. Miller
KFKirstin Frost
Kirstin Frost
ESEmily L. Smith
Emily L. Smith
YJYuhan Jin
Yuhan Jin
JUJodie Ulaszek
Jodie Ulaszek
GTGregory H. Tyson
Gregory H. Tyson
Since March 2024, H5N1 highly pathogenic avian influenza (HPAI) has been detected in U.S. dairy cattle. Infectious virus shed in unpasteurized milk, a matrix not previously evaluated for H5N1 detection, makes real-time reverse transcription quantitative polymerase chain reaction (rRT-qPCR) assays critical for animal diagnostics and food safety through screening and early detection of milk samples. This interlaboratory comparison exercise evaluated the performance of PCR-based H5N1 assays across 45 participants from government, academic, and commercial laboratories using blinded milk samples spiked with an inactivated H5N1 virus culture at concentrations ranging from 85 to 170,000 genome copies/100 μL. Participants tested samples using their routine protocols. The rate of detection (ROD), Ct values, and levels of detection where 50% of the samples yielded a positive result (LOD50) were analyzed with methods grouped by extraction and PCR kit combinations for sensitivity comparison. For high-concentration samples (17,000 and 170,000 copies/100 μL), ROD was ≥99%; however, detection decreased significantly at lower concentrations, with only 34% of participants reliably detecting samples at 1,700 copies/100 μL and 24% at 85 copies/100 μL. Eight distinct method types were used by participants, with some methods consistently detecting low levels of virus, and others having a 0% detection rate at low copy levels. This study reveals substantial variability in H5N1 detection capabilities across laboratories, with method selection impacting sensitivity. This finding has important implications for human and animal health surveillance and emergency response, highlighting the need for evaluation of protocols and quality control measures for H5N1 testing in milk.