scholarly journals Evaluation of sample preservation and storage methods for metaproteomics analysis of intestinal microbiomes

2021 ◽  
Author(s):  
Angie Mordant ◽  
Manuel Kleiner
Keyword(s):  
Gene Expression ◽  
Liquid Nitrogen ◽  
Room Temperature ◽  
The Other ◽  
Intestinal Microbiome ◽  
Protein Abundance ◽  
Fecal Microbiome ◽  
Storage Methods ◽  
And Storage ◽  
Measure Gene Expression

A critical step in studies of the intestinal microbiome using meta-omics approaches is the preservation of samples before analysis. Preservation is essential for approaches that measure gene expression, such as metaproteomics, which is used to identify and quantify proteins in microbiomes. Intestinal microbiome samples are typically stored by flash freezing and storage at -80 oC, but some experimental set-ups do not allow for immediate freezing of samples. In this study, we evaluated methods to preserve fecal microbiome samples for metaproteomics analyses when flash freezing is not possible. We collected fecal samples from C57BL/6 mice and stored them for 1 and 4 weeks using the following methods: flash-freezing in liquid nitrogen, immersion in RNAlater™, immersion in 95% ethanol, immersion in a RNAlater-like buffer, and combinations of these methods. After storage we extracted protein and prepared peptides for LC-MS/MS analysis to identify and quantify peptides and proteins. All samples produced highly similar metaproteomes, except for ethanol-preserved samples that were distinct from all other samples in terms of protein identifications and protein abundance profiles. Flash-freezing and RNAlater™ (or RNAlater-like treatments) produced metaproteomes that differed only slightly, with less than 0.7% of identified proteins differing in abundance. In contrast, ethanol preservation resulted in an average of 9.5% of the identified proteins differing in abundance between ethanol and the other treatments. Our results suggest that preservation at room temperature in RNAlater™,or an RNAlater-like solution, performs as well as freezing for the preservation of intestinal microbiome samples before metaproteomics analyses.

scholarly journals Sarin and Air Permeation Through a Nanoporous Graphene

MRS Advances ◽  
2020 ◽  
Vol 5 (27-28) ◽  
pp. 1475-1482
Author(s):  
Marco A. Maria ◽  
Alexandre F. Fonseca
Keyword(s):  
Room Temperature ◽  
Initial Pressure ◽  
Chemical Warfare Agent ◽  
The Other ◽  
Graphene Nanosheet ◽  
Different Temperatures ◽  
Nanoporous Graphene ◽  
Dynamics Simulations ◽  
And Storage ◽  
Air Permeation

ABSTRACTSarin gas is a dangerous chemical warfare agent (CWA). It is a nerve agent capable of bringing a person to death in about 15 minutes. A lethal concentration of sarin molecules in air is about 30 mg/m3. Experimental research on this gas requires very careful safety protocols for handling and storage. Therefore, theoretical and computational studies on sarin gas are very welcome and might provide important safe guides towards the management of this lethal substance. In this work, we investigated the interactions between sarin, air and nanoporous graphene, using tools of classical molecular dynamics simulations. Aiming to cast some light in the possible sarin selective filtration by graphene, we designed a bipartite simulation box with a porous graphene nanosheet placed at the middle. Sarin and air molecules were initially placed only on one side of the box so as to create an initial pressure towards the passage of both to the other side. The box dimensions were chosen so that the hole in the graphene was the only possible way through which sarin and air molecules can get to the other side of the box. The number of molecules that passed through the hole in graphene was monitored during 10 ns of simulation and the results for different temperatures were compared. The results show that, as far as the size of the holes are small, van der Waals forces between graphene and the molecules play a significant role on keeping sarin near graphene, at room temperature.

Electrochemical Hydriding of Mg-Based Alloys

2011 ◽  
Vol 312-315 ◽  
pp. 882-887
Author(s):  
Dalibor Vojtěch ◽  
Vítězslav Knotek ◽  
Pavel Novák
Keyword(s):  
Hydrogen Storage ◽  
High Temperatures ◽  
Room Temperature ◽  
Hydrogen Atmosphere ◽  
The Other ◽  
High Hydrogen ◽  
Hydrogen Saturation ◽  
Other Hand ◽  
Mechanism And Kinetics ◽  
Storage Methods

Mg-based alloys are prospective materials for reversible hydrogen storage in the form of metallic hydrides. Usually, hydrogen saturation is carried out at high temperatures and high hydrogen pressures. This is the reason for the high cost of metallic hydrides in comparison with other hydrogen storage methods. Electrochemical hydriding, on the other hand, can be realized at room temperature. Moreover, this process does not need any hydrogen atmosphere. In the presented work, electrochemical hydriding of several Mg-Ni-Mm-based alloys (Mm = mishmetal) is performed. Hydriding efficiency, mechanism and kinetics are described. It is shown that the additions of Ni, Mm and the formation of eutectic structures support hydriding of alloys.

Infrared Spectrum of Potassium Oxalate Monohydrate at Liquid Nitrogen Temperature

1970 ◽  
Vol 24 (6) ◽  
pp. 598-601 ◽  
Author(s):  
V. S. Tomar ◽  
H. D. Bist ◽  
D. P. Khandelwal
Keyword(s):  
Infrared Spectrum ◽  
Liquid Nitrogen ◽  
Ir Spectrum ◽  
Room Temperature ◽  
Considerable Increase ◽  
Liquid Nitrogen Temperature ◽  
The Other ◽  
Potassium Oxalate ◽  
Spectral Changes

The ir spectrum of K2C2O4. H2O is reported at liquid nitrogen temperature (LNT). On the basis of present work and earlier Raman studies, the frequencies at 3400, 3250, 1615, 1600, 1577, 1487, 1311, 902, 780, 605, 522, 449, 353, and 305 cm−1 have been assigned to the fundamental internal modes of C2O4 and H2O groups. In addition, the wagging and rocking modes of bonded water have been assigned unambiguously at 737 and 646 cm−1, respectively. Compared with the spectrum at room temperature, the spectral changes on cooling to LNT are as follows: (1) The bands at 522 and 1311 cm−1 each show splitting into two bands; (2) the librational modes of crystalline H2O show considerable increase in peak intensities accompanied by sharpening and a shift of about +20 cm−1; and (3) among the internal modes of H2O the symmetric stretching mode at 3250 cm−1 shows greater enhancement than the other two modes.

scholarly journals Effects of Sample Collection and Storage Methods on Antipneumococcal Immunoglobulin A in Saliva

2003 ◽  
Vol 10 (3) ◽  
pp. 357-361 ◽  
Author(s):  
A. Nurkka ◽  
J. Obiero ◽  
H. Käyhty ◽  
J. A. G. Scott
Keyword(s):  
Liquid Nitrogen ◽  
Enzyme Inhibitors ◽  
Immunoglobulin A ◽  
Sample Collection ◽  
Protease Enzyme ◽  
Storage Methods ◽  
Commercial Kits ◽  
Capsular Antigens ◽  
And Storage ◽  
Collection Methods

ABSTRACT Saliva contains components of both the mucosal and systemic immune systems. Variable flow rates, immunoglobulin proteases, and variation in collection and storage methods all introduce differences in the estimated concentrations of antibodies. We evaluated the effect of four collection methods and three storage protocols on the concentrations of immunoglobulin A (IgA) antibodies to pneumococcal capsular antigens 1, 5, 6B, and 14 and to pneumococcal surface adhesin A (PsaA) in saliva. Specimens were collected from 30 healthy Kenyan adults by collecting drool, by pipette suction, and with two commercial kits, OraSure and Oracol. Aliquots from each specimen were snap-frozen with glycerol in liquid nitrogen or stored for 4 to 8 h at +4°C either with or without the addition of protease enzyme inhibitors prior to storage at −70°C. Anticapsular IgA concentrations were not significantly different with different collection methods, but snap-freezing the specimens in liquid nitrogen led to concentrations 41 to 47% higher than those of specimens stored by the other methods (P < 0.0005).

scholarly journals Evaluation of Sample Preservation and Storage Methods for Metaproteomics Analysis of Intestinal Microbiomes

2021 ◽  
Author(s):  
Angie Mordant ◽  
Manuel Kleiner
Keyword(s):  
Microbial Community ◽  
Direct Evidence ◽  
Intestinal Microbiome ◽  
Community Members ◽  
Host Proteins ◽  
Sample Preservation ◽  
Storage Methods ◽  
And Storage

Metaproteomics is a powerful tool to study the intestinal microbiome. By identifying and quantifying a large number of microbial, dietary, and host proteins in microbiome samples, metaproteomics provides direct evidence of the activities and functions of microbial community members.

A Liquid Nitrogen Cooled Stage for STEM

1974 ◽  
Vol 32 ◽  
pp. 444-445
Author(s):  
Louis T. Germinario
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Liquid Nitrogen ◽  
Room Temperature ◽  
Objective Lens ◽  
Thermal Drift ◽  
Specimen Holder ◽  
Resolution Capability ◽  
Focal Position

A liquid nitrogen stage has been developed for the JEOL JEM-100B electron microscope equipped with a scanning attachment. The design is a modification of the standard JEM-100B SEM specimen holder with specimen cooling to any temperatures In the range ~ 55°K to room temperature. Since the specimen plane is maintained at the ‘high resolution’ focal position of the objective lens and ‘bumping’ and thermal drift la minimized by supercooling the liquid nitrogen, the high resolution capability of the microscope is maintained (Fig.4).

Electron microscope studies of the plastic deformation of ternary alloys based on GaAs

1990 ◽  
Vol 48 (4) ◽  
pp. 1120-1120
Author(s):  
R. Haswell ◽  
U. Bangert ◽  
P. Charsley
Keyword(s):  
Plastic Deformation ◽  
Electron Microscope ◽  
Room Temperature ◽  
Stacking Faults ◽  
The Other ◽  
Ternary Alloys ◽  
Dislocation Mobility ◽  
Semiconducting Materials ◽  
Micro Indentation

A knowledge of the behaviour of dislocations in semiconducting materials is essential to the understanding of devices which use them . This work is concerned with dislocations in alloys related to the semiconductor GaAs . Previous work on GaAs has shown that microtwinning occurs on one of the <110> rosette arms after indentation in preference to the other . We have shown that the effect of replacing some of the Ga atoms by Al results in microtwinning in both of the rosette arms.In the work to be reported dislocations in specimens of different compositions of Gax Al(1-x) As and Gax In(1-x) As have been studied by using micro indentation on a (001) face at room temperature . A range of electron microscope techniques have been used to investigate the type of dislocations and stacking faults/microtwins in the rosette arms , which are parallel to the [110] and [10] , as a function of composition for both alloys . Under certain conditions microtwinning occurs in both directions . This will be discussed in terms of the dislocation mobility.

Investigations on the Nature of Hemophilia A

1963 ◽  
Vol 09 (01) ◽  
pp. 030-052 ◽  
Author(s):  
Eberhard Mammen
Keyword(s):  
Factor Viii ◽  
Human Plasma ◽  
Barium Sulfate ◽  
Freeze Drying ◽  
Room Temperature ◽  
Hemophilia A ◽  
Normal Human Plasma ◽  
Normal Human ◽  
And Storage ◽  
Prothrombin Activation

SummaryIn this paper an inhibitor is described that is found in hemophilic plasma and serum different from any till now described inhibitor. The inhibitor only inhibits prothrombin activation in the “intrinsic clotting systems”. This inhibitor is probably not present in normal human plasma or serum. It is destroyed by ether and freeze drying, is labile to acid and storage at room temperature. It is stable upon dialysis and has not been adsorbed on barium sulfate, aluminum hydroxide or kaolin. It precipitates at 50% v/v saturation with alcohol. The nature of this inhibitor seems to be a protein or lipoprotein.Factor VIII was isolated from hemophilic plasma. The amount isolated was the same as from normal plasma and the activity properties were not different. Hemophiliacs have normal amounts of factor VIII.

Reparação óssea no implante dental

2020 ◽  
Vol 12 (45) ◽  
pp. 63-66
Author(s):  
Halim Nagem Filho ◽  
Reinaldo Francisco Maia ◽  
Reinaldo Missaka ◽  
Nasser Hussein Fares
Keyword(s):  
Gene Expression ◽  
Titanium Surface ◽  
Close Contact ◽  
The Other ◽  
Main Function ◽  
Indirect Interaction ◽  
M2 Macrophages ◽  
Activated Macrophages ◽  
M1 Macrophages ◽  
High Production

The osseointegration is the stable and functional union between the bone and a titanium surface. A new bone can be found on the surface of the implant about 1 week after its installation; the bone remodeling begins between 6 and 12 weeks and continues throughout life. After the implant insertion, depending on the energy of the surface, the plasma fluid immediately adheres, in close contact with the surface, promoting the adsorption of proteins and inducing the indirect interaction of the cells with the material. Macrophages are cells found in the tissues and originated from bone marrow monocytes. The M1 macrophages orchestrate the phagocytic phase in the inflammatory region and also produce inflammatory cytokines involved with the chronic inflammation and the cleaning of the wound and damaged tissues from bacteria. On the other hand, alternative-activated macrophages (M2) are activated by IL-10, the immune complex. Its main function consists on regulating negatively the inflammation through the secretion of the immunosuppressant IL-10. The M2 macrophages present involvement with the immunosuppression, besides having a low capacity for presenting antigens and high production of cytokines; these can be further divided into M2a, M2b, and M2c, based on the gene expression profile.

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