scholarly journals Transmembrane protein western blotting: Impact of sample preparation on detection of SLC11A2 (DMT1) and SLC40A1 (ferroportin)

PLoS ONE ◽  
2020 ◽  
Vol 15 (7) ◽  
pp. e0235563
Author(s):  
Yoshiaki Tsuji
Author(s):  
Masayuki Morita ◽  
Bernard N. Kanoi ◽  
Naoaki Shinzawa ◽  
Rie Kubota ◽  
Hiroyuki Takeda ◽  
...  

Precise subcellular localization of proteins is the key to elucidating the physiological role of these molecules in malaria parasite development, understanding of pathogenesis, and protective immunity. In Plasmodium falciparum, however, detection of proteins in the blood-stage parasites is greatly hampered by the lack of versatile protein tags which can intrinsically label such molecules. Thus, in this study, to develop a novel system that can be used to evaluate subcellular localization of known and novel proteins, we assessed the application of AGIA tag, consisting of 9 amino acids (EEAAGIARP), in P. falciparum blood-stage parasites. Specifically, AGIA-tagged ring-infected erythrocyte surface antigen (RESA-AGIA) was episomally expressed in P. falciparum 3D7 strain. The RESA-AGIA protein was detected by Western blotting and immunofluorescence assay (IFA) using recombinant rabbit anti-AGIA tag monoclonal antibody (mAb) with a high signal/noise ratio. Similarly, AGIA-tagged multidrug resistance protein 1 (MDR1-AGIA), as an example of polyptic transmembrane protein, was endogenously expressed and detected by Western blotting and IFA with anti-AGIA tag mAb. Immunoelectron microscopy of the RESA-AGIA transfected merozoites revealed that mouse anti-RESA and the rabbit anti-AGIA mAb signals could definitively co-localize to the dense granules. Put together, this study demonstrates AGIA tag/anti-AGIA rabbit mAb system as a potentially useful tool for elucidating the subcellular localization of new and understudied proteins in blood-stage malaria parasites at the nanometer-level resolution.


2004 ◽  
Vol 186 (7) ◽  
pp. 2052-2060 ◽  
Author(s):  
Tomas Edgren ◽  
Stefan Nordlund

ABSTRACT In our efforts to identify the components participating in electron transport to nitrogenase in Rhodospirillum rubrum, we used mini-Tn5 mutagenesis followed by metronidazole selection. One of the mutants isolated, SNT-1, exhibited a decreased growth rate and about 25% of the in vivo nitrogenase activity compared to the wild-type values. The in vitro nitrogenase activity was essentially wild type, indicating that the mutation affects electron transport to nitrogenase. Sequencing showed that the Tn5 insertion is located in a region with a high level of similarity to fixC, and extended sequencing revealed additional putative fix genes, in the order fixABCX. Complementation of SNT-1 with the whole fix gene cluster in trans restored wild-type nitrogenase activity and growth. Using Western blotting, we demonstrated that expression of fixA and fixB occurs only under conditions under which nitrogenase also is expressed. SNT-1 was further shown to produce larger amounts of both ribulose 1,5-bisphosphate carboxylase/oxgenase and polyhydroxy alkanoates than the wild type, indicating that the redox status is affected in this mutant. Using Western blotting, we found that FixA and FixB are soluble proteins, whereas FixC most likely is a transmembrane protein. We propose that the fixABCX genes encode a membrane protein complex that plays a central role in electron transfer to nitrogenase in R. rubrum. Furthermore, we suggest that FixC is the link between nitrogen fixation and the proton motive force generated in the photosynthetic reactions.


Author(s):  
R. E. Ferrell ◽  
G. G. Paulson ◽  
C. W. Walker

Selected area electron diffraction (SAD) has been used successfully to determine crystal structures, identify traces of minerals in rocks, and characterize the phases formed during thermal treatment of micron-sized particles. There is an increased interest in the method because it has the potential capability of identifying micron-sized pollutants in air and water samples. This paper is a short review of the theory behind SAD and a discussion of the sample preparation employed for the analysis of multiple component environmental samples.


Author(s):  
T. J. Magee ◽  
J. Peng ◽  
J. Bean

Cadmium telluride has become increasingly important in a number of technological applications, particularly in the area of laser-optical components and solid state devices, Microstructural characterizations of the material have in the past been somewhat limited because of the lack of suitable sample preparation and thinning techniques. Utilizing a modified jet thinning apparatus and a potassium dichromate-sulfuric acid thinning solution, a procedure has now been developed for obtaining thin contamination-free samples for TEM examination.


Author(s):  
Earl R. Walter ◽  
Glen H. Bryant

With the development of soft, film forming latexes for use in paints and other coatings applications, it became desirable to develop new methods of sample preparation for latex particle size distribution studies with the electron microscope. Conventional latex sample preparation techniques were inadequate due to the pronounced tendency of these new soft latex particles to distort, flatten and fuse on the substrate when they dried. In order to avoid these complications and obtain electron micrographs of undistorted latex particles of soft resins, a freeze-dry, cold shadowing technique was developed. The method has now been used in our laboratory on a routine basis for several years.The cold shadowing is done in a specially constructed vacuum system, having a conventional mechanical fore pump and oil diffusion pump supplying vacuum. The system incorporates bellows type high vacuum valves to permit a prepump cycle and opening of the shadowing chamber without shutting down the oil diffusion pump. A baffeled sorption trap isolates the shadowing chamber from the pumps.


Author(s):  
Jayesh Bellare

Seeing is believing, but only after the sample preparation technique has received a systematic study and a full record is made of the treatment the sample gets.For microstructured liquids and suspensions, fast-freeze thermal fixation and cold-stage microscopy is perhaps the least artifact-laden technique. In the double-film specimen preparation technique, a layer of liquid sample is trapped between 100- and 400-mesh polymer (polyimide, PI) coated grids. Blotting against filter paper drains excess liquid and provides a thin specimen, which is fast-frozen by plunging into liquid nitrogen. This frozen sandwich (Fig. 1) is mounted in a cooling holder and viewed in TEM.Though extremely promising for visualization of liquid microstructures, this double-film technique suffers from a) ireproducibility and nonuniformity of sample thickness, b) low yield of imageable grid squares and c) nonuniform spatial distribution of particulates, which results in fewer being imaged.


Author(s):  
P. B. Basham ◽  
H. L. Tsai

The use of transmission electron microscopy (TEM) to support process development of advanced microelectronic devices is often challenged by a large amount of samples submitted from wafer fabrication areas and specific-spot analysis. Improving the TEM sample preparation techniques for a fast turnaround time is critical in order to provide a timely support for customers and improve the utilization of TEM. For the specific-area sample preparation, a technique which can be easily prepared with the least amount of effort is preferred. For these reasons, we have developed several techniques which have greatly facilitated the TEM sample preparation.For specific-area analysis, the use of a copper grid with a small hole is found to be very useful. With this small-hole grid technique, TEM sample preparation can be proceeded by well-established conventional methods. The sample is first polished to the area of interest, which is then carefully positioned inside the hole. This polished side is placed against the grid by epoxy Fig. 1 is an optical image of a TEM cross-section after dimpling to light transmission.


Author(s):  
L. Mulestagno ◽  
J.C. Holzer ◽  
P. Fraundorf

Due to the wealth of information, both analytical and structural that can be obtained from it TEM always has been a favorite tool for the analysis of process-induced defects in semiconductor wafers. The only major disadvantage has always been, that the volume under study in the TEM is relatively small, making it difficult to locate low density defects, and sample preparation is a somewhat lengthy procedure. This problem has been somewhat alleviated by the availability of efficient low angle milling.Using a PIPS® variable angle ion -mill, manufactured by Gatan, we have been consistently obtaining planar specimens with a high quality thin area in excess of 5 × 104 μm2 in about half an hour (milling time), which has made it possible to locate defects at lower densities, or, for defects of relatively high density, obtain information which is statistically more significant (table 1).


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