scholarly journals Identification, characterization, and application of a highly sensitive lactam biosensor from Pseudomonas putida

2019 ◽  
Author(s):  
Mitchell G. Thompson ◽  
Allison N. Pearson ◽  
Jesus F. Barajas ◽  
Pablo Cruz-Morales ◽  
Nima Sedaghatian ◽  
...  
Keyword(s):  
Pseudomonas Putida ◽  
High Sensitivity ◽  
Biological Pathways ◽  
Biological Synthesis ◽  
Polymer Precursor ◽  
Development Times ◽  
Highly Sensitive ◽  
Speed Up ◽  
Exogenous Ligand

ABSTRACTCaprolactam is an important polymer precursor to nylon traditionally derived from petroleum and produced on a scale of 5 million tons per year. Current biological pathways for the production of caprolactam are inefficient with titers not exceeding 2 mg/L, necessitating novel pathways for its production. As development of novel metabolic routes often require thousands of designs and result in low product titers, a highly sensitive biosensor for the final product has the potential to rapidly speed up development times. Here we report a highly sensitive biosensor for valerolactam and caprolactam from Pseudomonas putida KT2440 which is >1000x more sensitive to exogenous ligand than previously reported sensors. Manipulating the expression of the sensor oplR (PP_3516) substantially altered the sensing parameters, with various vectors showing Kd values ranging from 700 nM (79.1 μg/L) to 1.2 mM (135.6 mg/L). Our most sensitive construct was able to detect in vivo production of caprolactam above background at ~6 μg/L. The high sensitivity and range of OplR is a powerful tool towards the development of novel routes to the biological synthesis of caprolactam.

Optically pumped magnetometers enable a new level of biomagnetic measurements

2020 ◽  
Vol 9 (5) ◽  
pp. 247-251
Author(s):  
Tilmann Sander ◽  
Anna Jodko-Władzińska ◽  
Stefan Hartwig ◽  
Rüdiger Brühl ◽  
Thomas Middelmann
Keyword(s):  
Quantum Interference ◽  
High Sensitivity ◽  
High Temporal Resolution ◽  
Optically Pumped ◽  
New Class ◽  
Magnetic Shields ◽  
Highly Sensitive ◽  
Electric And Magnetic Fields ◽  
Auditory Evoked Fields

AbstractThe electrophysiological activities in the human body generate electric and magnetic fields that can be measured noninvasively by electrodes on the skin, or even, not requiring any contact, by magnetometers. This includes the measurement of electrical activity of brain, heart, muscles and nerves that can be measured in vivo and allows to analyze functional processes with high temporal resolution. To measure these extremely small magnetic biosignals, traditionally highly sensitive superconducting quantum-interference devices have been used, together with advanced magnetic shields. Recently, they have been complemented in usability by a new class of sensors, optically pumped magnetometers (OPMs). These quantum sensors offer a high sensitivity without requiring cryogenic temperatures, allowing the design of small and flexible sensors for clinical applications. In this letter, we describe the advantages of these upcoming OPMs in two exemplary applications that were recently carried out at Physikalisch-Technische Bundesanstalt (PTB): (1) magnetocardiography (MCG) recorded during exercise and (2) auditory-evoked fields registered by magnetoencephalography.

What can we Predict Before it's Implanted?

1985 ◽  
Vol 55 ◽  
Author(s):  
Donald F. Gibbons
Keyword(s):  
Biological Response ◽  
High Sensitivity ◽  
Biological Pathways ◽  
Surface Topology ◽  
Dystrophic Calcification ◽  
Vitro Assay ◽  
In Vivo Assays ◽  
Tissue Interface

ABSTRACTThe material factors which relate to the degradation and/or leaching of ions or molecules are described and the possible biological pathways which they may activate are described, i.e. cytotoxic, immune, tumor and nonspecific inflammatory response. Cytotoxicity is the only biological response which may be measured with high sensitivity by an in vitro assay prior to implantation. All other biological pathways require some degree of in vivo involvement. Three examples of biological response to material factors associated with devices which require evaluation by in vivo assays are discussed, namely: surface topology (texture), mechanically induced factors at the device/tissue interface caused by differences in compliance, and dystrophic calcification in connective tissue and vascular devices.

scholarly journals High Sensitivity In Vivo Imaging of Cancer Metastasis Using a Near-Infrared Luciferin Analogue seMpai

2020 ◽  
Vol 21 (21) ◽  
pp. 7896
Author(s):  
Jun Nakayama ◽  
Ryohei Saito ◽  
Yusuke Hayashi ◽  
Nobuo Kitada ◽  
Shota Tamaki ◽  
...  
Keyword(s):  
Single Cell ◽  
In Vivo Imaging ◽  
Cancer Metastasis ◽  
Near Infrared ◽  
High Sensitivity ◽  
Single Cell Level ◽  
Background Signal ◽  
Cell Level ◽  
Highly Sensitive

Bioluminescence imaging (BLI) is useful to monitor cell movement and gene expression in live animals. However, D-luciferin has a short wavelength (560 nm) which is absorbed by tissues and the use of near-infrared (NIR) luciferin analogues enable high sensitivity in vivo BLI. The AkaLumine-AkaLuc BLI system (Aka-BLI) can detect resolution at the single-cell level; however, it has a clear hepatic background signal. Here, to enable the highly sensitive detection of bioluminescence from the surrounding liver tissues, we focused on seMpai (C15H16N3O2S) which has been synthesized as a luciferin analogue and has high luminescent abilities as same as AkaLumine. We demonstrated that seMpai BLI could detect micro-signals near the liver without any background signal. The solution of seMpai was neutral; therefore, seMpai imaging did not cause any adverse effect in mice. seMpai enabled a highly sensitive in vivo BLI as compared to previous techniques. Our findings suggest that the development of a novel mutated luciferase against seMpai may enable a highly sensitive BLI at the single-cell level without any background signal. Novel seMpai BLI system can be used for in vivo imaging in the fields of life sciences and medicine.

scholarly journals Digital PCR to quantify ChAdOx1 nCoV-19 copies in blood and tissues

2021 ◽  
Author(s):  
Anita Badbaran ◽  
Reiner Mailer ◽  
Christine Dahlke ◽  
Jannis Woens ◽  
Anahita Fathi ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
High Sensitivity ◽  
Digital Pcr ◽  
Quantitative Detection ◽  
Highly Sensitive ◽  
Life Threatening ◽  
Thrombotic Complications ◽  
Cerebral Sinus

AbstractVaccination with the adenoviral-vector based Astra Zeneca ChAdOx1 nCov-19 vaccine is efficient and safe. However, in rare cases vaccinated individuals developed life-threatening thrombotic complications, including thrombosis in cerebral sinus and splanchnic veins. Monitoring of the applied vector in vivo represents an important precondition to study the molecular mechanisms underlying vaccine-driven adverse effects now referred to as vaccine-induced immune thrombotic thrombocytopenia (VITT). We previously have shown that digital PCR is an excellent tool to quantify transgene copies in vivo. Here we present a highly sensitive digital PCR for in-situ quantification of ChAdOx1 nCoV-19 copies. Using this method, we quantified vector copies in human serum 24, 72 and 168 hours post vaccination, and in a variety of murine tissues in an experimental vaccination model 30 minutes post injection. We describe a method for high-sensitivity quantitative detection of ChAdOx1 nCoV-19 with possible implications to elucidate the mechanisms of severe ChAdOx1 nCov-19 vaccine complications.

Detecting and imaging of SO2 derivatives in living cells with zero cross-talk colorimetric mitochondria-targeted fluorescent probe

2020 ◽  
Vol 98 (1) ◽  
pp. 1-6
Author(s):  
Dan Wu ◽  
Shiqi Rong ◽  
Yi Liu ◽  
Fei Zheng ◽  
Yankun Zhao ◽  
...  
Keyword(s):  
High Resolution ◽  
Cross Talk ◽  
High Sensitivity ◽  
Living Cells ◽  
High Resolution Imaging ◽  
Biochemical Processes ◽  
Highly Sensitive ◽  
Resolution Imaging ◽  
Low Cytotoxicity

It is well known that excessive levels of sulfur dioxide and its derivatives are connected to diverse diseases. Therefore, developing highly sensitive probes to detect and monitor sulfite in living cells is important for the diagnosis of disease and the study of biochemical processes in vivo. In this report, two zero cross-talk ratiometric fluorescent probes were synthesized (CA-ID-MC and CA-BI-MC), which were derived from carbazole-indolenine π-conjugated system for effective detection of sulfite in living cells. Observably, CA-BI-MC exhibited the largest emission shift of 157 nm from 617 to 460 nm with the addition of various concentrations of sulfite, which is beneficial for high-resolution imaging of the sulfite. CA-BI-MC also exhibits high sensitivity and low cytotoxicity. More importantly, this probe successfully located mitochondria and sensed the sulfite in HeLa cells caused by exogenous stimulation.

scholarly journals Diagnosis of Tuberculosis Based on the Two Specific Antigens ESAT-6 and CFP10

2000 ◽  
Vol 7 (2) ◽  
pp. 155-160 ◽  
Author(s):  
Laurens A. H. van Pinxteren ◽  
Pernille Ravn ◽  
Else Marie Agger ◽  
John Pollock ◽  
Peter Andersen
Keyword(s):  
Natural Infection ◽  
High Sensitivity ◽  
Delayed Type Hypersensitivity ◽  
Purified Protein Derivative ◽  
Environmental Mycobacteria ◽  
Diagnostic Potential ◽  
Highly Sensitive ◽  
Specific Antigens

ABSTRACT Tests based on tuberculin purified protein derivative (PPD) cannot distinguish between tuberculosis infection, Mycobacterium bovis BCG vaccination, or exposure to environmental mycobacteria. The present study investigated the diagnostic potential of twoMycobacterium tuberculosis-specific antigens (ESAT-6 and CFP10) in experimental animals as well as during natural infection in humans and cattle. Both antigens were frequently recognized in vivo and in vitro based on the induction of delayed-type hypersensitivity responses and the ability to induce gamma interferon production by lymphocytes, respectively. The combination of ESAT-6 and CFP10 was found to be highly sensitive and specific for both in vivo and in vitro diagnosis. In humans, the combination had a high sensitivity (73%) and a much higher specificity (93%) than PPD (7%).

scholarly journals Highly Sensitive Silicon Nanowire Biosensor Devices for the Investigation of UniCAR Platform in Immunotherapy

2021 ◽  
Vol 6 (1) ◽  
pp. 20
Author(s):  
Trang-Anh Nguyen-Le ◽  
Diana Isabel Sandoval Bojorquez ◽  
Arnau Pérez Roig ◽  
Bergoi Ibarlucea ◽  
Gianaurelio Cuniberti ◽  
...  
Keyword(s):  
T Cells ◽  
Therapeutic Potential ◽  
Silicon Nanowire ◽  
Cmos Technology ◽  
Label Free ◽  
Antigen Receptors ◽  
Highly Sensitive ◽  
Speed Up ◽  
Analytical Tools

Although showing impressive therapeutic potential, treatments of leukemias with T-cells expressing chimeric antigen receptors (CARs) is limited by their risk of several severe side effects. To overcome these problems, a switchable CAR platform has been developed termed UniCAR. Unlike conventional CAR, which is directed against tumor-associated antigens, UniCAR treatment involves an intermediate target module (TM), which can cross-link UniCAR T cells with tumor cells and lead to destruction. The development of these novel TMs against different tumor targets requires numerous repetitive tests on different synthesizing trials, which is usually limited in quantity and time-consuming. Meanwhile, nano-biosensors are lately known as analytical tools, which are highly sensitive, label-free, rapid and reagent-saving. Among them, silicon nanowire (SiNW) sensors have been extensively investigated by researchers over the past decades thanks to their compatibility with CMOS technology, enabling mass production. In this work, we demonstrated the application of a previously published SiNW biosensor on the detection of the binding of UniCAR and a part of different TMs. The results underline the advantages of the SiNW sensor over the ELISA method in terms of ease of preparation, speed and sensitivity. The method is able to evaluate the binding affinity of UniCAR to different TMs and open a potential to quantify the number of active UniCAR T-cells in an in vivo sample at a later stage. In the end, the application of a nanosensor may speed up the R&D process of the UniCAR concept and later play an important role in clinical monitoring of immunotherapy, especially in the era of precision medicine.

High-sensitivity detection of gold labels by high-angle dark-field STEM imaging

1990 ◽  
Vol 48 (3) ◽  
pp. 892-893 ◽  
Author(s):  
Max T. Otten
Keyword(s):  
High Sensitivity ◽  
Dark Field ◽  
Bright Field ◽  
Backscattered Electron Imaging ◽  
Backscattered Electrons ◽  
Average Atomic Number ◽  
Highly Sensitive ◽  
Backscattered Electron ◽  
Electron Imaging ◽  
High Sensitivity Detection

Labelling of antibodies with small gold probes is a highly sensitive technique for detecting specific molecules in biological tissue. Larger gold probes are usually well visible in TEM or STEM Bright-Field images of unstained specimens. In stained specimens, however, the contrast of the stain is frequently the same as that of the gold labels, making it virtually impossible to identify the labels, especially when smaller gold labels are used to increase the sensitivity of the immunolabelling technique. TEM or STEM Dark-Field images fare no better (Figs. 1a and 2a), again because of the absence of a clear contrast difference between gold labels and stain.Potentially much more useful is backscattered-electron imaging, since this will show differences in average atomic number which are sufficiently large between the metallic gold and the stains normally used. However, for the thin specimens and at high accelerating voltages of the STEM, the yield of backscattered electrons is very small, resulting in a very weak signal. Consequently, the backscattered-electron signal is often too noisy for detecting small labels, even for large spot sizes.

Improvement of effectiveness in maize breeding

2006 ◽  
Vol 54 (3) ◽  
pp. 351-358 ◽  
Author(s):  
P. Pepó
Keyword(s):  
Recurrent Selection ◽  
Genetic Manipulation ◽  
Field Testing ◽  
Tissue Cultures ◽  
Maize Breeding ◽  
Breeding Programmes ◽  
Speed Up ◽  
Selection For

Plant regeneration via tissue culture is becoming increasingly more common in monocots such as maize (Zea mays L.). Pollen (gametophytic) selection for resistance to aflatoxin in maize can greatly facilitate recurrent selection and the screening of germplasm for resistance at much less cost and in a shorter time than field testing. In vivo and in vitro techniques have been integrated in maize breeding programmes to obtain desirable agronomic attributes, enhance the genes responsible for them and speed up the breeding process. The efficiency of anther and tissue cultures in maize and wheat has reached the stage where they can be used in breeding programmes to some extent and many new cultivars produced by genetic manipulation have now reached the market.

NGHIÊN CỨU SỬ DỤNG MÀNG BAO SINH HỌC TỪ DỊCH CHIẾT VI KHUẨN Pseudomonas putida 199B ĐẾN KHÁNG NẤM Aspergilus flavus T1 TRONG QUÁ TRÌNH BẢO QUẢN HẠT GIỐNG NGÔ

2017 ◽  
Vol 126 (3C) ◽  
Author(s):  
Nguyễn Thỵ Đan Huyền ◽  
Lê Thanh Long ◽  
Trần Thị Thu Hà ◽  
Nguyễn Cao Cường ◽  
Nguyễn Hiền Trang
Keyword(s):  
Pseudomonas Putida ◽  
28S Rrna

Chủng T1 phân lập từ các mẫu ngô nếp NK66 nhiễm nấm mốc tự nhiên được sử dụng để nghiên cứu khả năng kháng nấm của dịch chiết vi khuẩn Pseudomonas putida 199B. Đặc điểm hình thái của chủng T1 đã được quan sát đại thể (màu sắc, hình dáng, kích thước khuẩn lạc) trên môi trường PDA và vi thể (hình dáng bào tử) trên kính hiển vi kết hợp so sánh với loài Aspergilus flavus đối chứng. Kết quả phân tích trình tự gen mã hóa 28S rRNA của chủng T1 cho thấy sự tương đồng trình tự cao với các trình tự tương ứng của loài Aspergilus flavus trên ngân hàng gen. Kết quả khảo sát ảnh hưởng của dịch chiết vi khuẩn P. putida lên sự phát triển của nấm A.  flavus gây bệnh trên hạt ngô sau thu hoạch và bảo quản ở điều kiện in vitro cho thấy, ở nồng độ P. putida 24% đã ức chế 74,50% sự phát triển đường kính tản nấm sau 10 ngày nuôi cấy, ức chế 79,63% sự hình thành sinh khối sợi nấm sau 7 ngày nuôi cấy. Ở điều kiện in vivo, sự nảy mầm của hạt giống ngô sau 30 ngày được tạo màng bao sinh học bằng dịch chiết vi khuẩn P. putida nồng độ 18% đạt 97,91%, tỉ lệ hạt nhiễm nấm mốc giảm còn 20% so với 72% ở mẫu đối chứng.

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