141 research outputs found
A simple and efficient method for extraction of Taq DNA polymerase
Background: Thermostable DNA polymerase (Taq Pol \u399) from Thermus
aquaticus has beenwidely used in PCR, which was usually extracted
with Pluthero's method. Themethod used ammonium sulfate to precipitate
the enzyme, and it saved effort and money but not time. Moreover, we
found that 30\u201340% activity of Taq Pol I was lost at the ammonium
sulfate precipitation step, and the product contained a small amount of
DNA. Results: We provided a novel, simplified and low-costmethod to
purify the Taq Pol \u399 after overproduction of the enzyme in
Escherichia coli , which used ethanol instead of ammonium sulfate to
precipitate the enzyme. The precipitate can be directly dissolved in
the storage buffer without dialysis. In addition, DNA and RNA
contamination was removed with DNase I and RNase A before
precipitation, and the extraction procedure was optimized. Our
improvements increase recovery rate and specific activity of the
enzyme, and save labor, time, and cost. Conclusions: Our method uses
ethanol, DNase I, and RNase A to purify the Taq Pol \u399, and
simplifies the operation, and increases the enzyme recovery rate and
quality
Graphene quantum dots induce cascadic apoptosis via interaction with proteins associated with anti-oxidation after endocytosis by Trypanosoma brucei
Trypanosoma brucei, the pathogen causing African sleeping sickness (trypanosomiasis) in humans, causes debilitating diseases in many regions of the world, but mainly in African countries with tropical and subtropical climates. Enormous efforts have been devoted to controlling trypanosomiasis, including expanding vector control programs, searching for novel anti-trypanosomial agents, and developing vaccines, but with limited success. In this study, we systematically investigated the effect of graphene quantum dots (GQDs) on trypanosomal parasites and their underlying mechanisms. Ultrasmall-sized GQDs can be efficiently endocytosed by T. brucei and with no toxicity to mammalian-derived cells, triggering a cascade of apoptotic reactions, including mitochondrial disorder, intracellular reactive oxygen species (ROS) elevation, Ca2+ accumulation, DNA fragmentation, adenosine triphosphate (ATP) synthesis impairment, and cell cycle arrest. All of these were caused by the direct interaction between GQDs and the proteins associated with cell apoptosis and anti-oxidation responses, such as trypanothione reductase (TryR), a key protein in anti-oxidation. GQDs specifically inhibited the enzymatic activity of TryR, leading to a reduction in the antioxidant capacity and, ultimately, parasite apoptotic death. These data, for the first time, provide a basis for the exploration of GQDs in the development of anti-trypanosomials
Special Issue on Microlenses
The study and application of microscale lenses and lens arrays have been actively researched in recent years; new approaches in the fabrication of microlenses and microlens arrays have emerged. Also, novel applications of these microlenses and microlens arrays have been demonstrated. In an effort to disseminate the current advances in this specialized field of microlenses and microlens arrays, and to encourage discussion on the future research directions while stimulating research interests in this area, a Special Issue of Micromachines has been dedicated to “Microlenses”. [...
Optical MEMS for chemical analysis and biomedicine
This book describes the current state of optical MEMS in chemical and biomedical analysis and brings together current trends and highlights topics representing the most exciting progress in recent years in the field
Electromagnetically shielded high-Q CMOS-compatible copper inductors
[[abstract]]On-chip inductors are valuable components in radio-frequency (RF) circuits, which find widespread applications in wireless communication. The performance of current on-chip spiral inductors generally suffers from low quality factor (Q), the detrimental coupling between the device and its ambient via the silicon substrate, and the lack of a good RF ground plane because of the lossy substrate. A solution to these issues is to build a suspended spiral inductor over a cavity whose bottom plane and side-walls are metallized. The deep cavity can dramatically reduce the electromagnetic coupling and the parasitic capacitance between the inductor and the substrate, increasing Q and the self-resonant frequency[[fileno]]2020501030003[[department]]ĺ‹•ć©ź
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