scholarly journals Room-temperature-storable PCR Mixes for SARS-CoV-2 Detection

2020 ◽  
Author(s):  
Jiasu Xu ◽  
Jin Wang ◽  
Zecheng Zhong ◽  
Xiaosong Su ◽  
Kunyu Yang ◽  
...  
Keyword(s):  
Freeze Drying ◽  
Room Temperature ◽  
Karl Fischer Titration ◽  
Residual Moisture ◽  
Ambient Temperatures ◽  
Logistics Networks ◽  
Rapid Pcr ◽  
Freeze Dried ◽  
Novel Coronavirus ◽  
Sensitivity Specificity

AbstractA novel coronavirus (severe acute respiratory syndrome coronavirus 2, SARS-CoV-2) emerged in late 2019, causing an outbreak of pneumonia [coronavirus disease 2019 (COVID-19)] in Wuhan, China, which then rapidly spread globally. Although the use of ready-made reaction mixes can enable more rapid PCR-based diagnosis of COVID-19, the need to transport and store these mixes at low temperatures presents challenges to already overburdened logistics networks. Here, we present an optimized freeze-drying procedure that allows SARS-CoV-2 PCR mixes to be transported and stored at ambient temperatures, without loss of activity. Additive-supplemented PCR mixes were freeze-dried. The residual moisture of the freeze-dried PCR mixes was measured by Karl-Fischer titration. We found that freeze-dried PCR mixes with ∼1.2% residual moisture are optimal for storage, transport, and reconstitution. The sensitivity, specificity, and repeatability of the freeze-dried reagents were similar to those of freshly prepared, wet reagents. The freeze-dried mixes retained activity at room temperature (18∼25°C) for 28 days, and for 14 and 10 days when stored at 37°C and 56°C, respectively. The uptake of this approach will ease logistical challenges faced by transport networks and make more cold storage space available at diagnosis and hospital laboratories. This method can also be applied to the generation of freeze-dried PCR mixes for the detection of other pathogens.

Scanning Electron Microscopy-cuticular Lesions on the Roundworm Ascaris Suum

1970 ◽  
Vol 28 ◽  
pp. 114-115
Author(s):  
P. A. Madden ◽  
W. R. Anderson
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Freeze Drying ◽  
Room Temperature ◽  
Secondary Electron ◽  
Distilled Water ◽  
Freeze Dried ◽  
Silver Paint ◽  
To Come ◽  
Scanning Electron

The intestinal roundworm of swine is pinkish in color and about the diameter of a lead pencil. Adult worms, taken from parasitized swine, frequently were observed with macroscopic lesions on their cuticule. Those possessing such lesions were rinsed in distilled water, and cylindrical segments of the affected areas were removed. Some of the segments were fixed in buffered formalin before freeze-drying; others were freeze-dried immediately. Initially, specimens were quenched in liquid freon followed by immersion in liquid nitrogen. They were then placed in ampuoles in a freezer at −45C and sublimated by vacuum until dry. After the specimens appeared dry, the freezer was allowed to come to room temperature slowly while the vacuum was maintained. The dried specimens were attached to metal pegs with conductive silver paint and placed in a vacuum evaporator on a rotating tilting stage. They were then coated by evaporating an alloy of 20% palladium and 80% gold to a thickness of approximately 300 A°. The specimens were examined by secondary electron emmission in a scanning electron microscope.

scholarly journals Protective Effects of Tropical Fruit Processing Coproducts on Probiotic Lactobacillus Strains during Freeze-Drying and Storage

2020 ◽  
Vol 8 (1) ◽  
pp. 96 ◽  
Author(s):  
Caroliny Mesquita Araújo ◽  
Karoliny Brito Sampaio ◽  
Francisca Nayara Dantas Duarte Menezes ◽  
Erika Tayse da Cruz Almeida ◽  
Marcos dos Santos Lima ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Freeze Drying ◽  
Room Temperature ◽  
Membrane Integrity ◽  
Added Value ◽  
Protective Effects ◽  
Tropical Fruit ◽  
Freeze Dried ◽  
Fruit Processing ◽  
And Storage

This study evaluated the protective effects of coproducts from agroindustrial processing of the tropical fruits acerola (Malpighia glabra L., ACE), cashew (Anacardium occidentale L., CAS), and guava (Psidium guayaba L., GUA) on the probiotics Lactobacillus paracasei L-10, Lactobacillus casei L-26, and Lactobacillus acidophilus LA-05 during freeze-drying and storage. The occurrence of damage to membrane integrity, membrane potential, and efflux activity of Lactobacillus cells after freeze-drying was evaluated by flow cytometry, and viable counts were measured immediately after freeze-drying and during 90 days of storage under refrigerated or room temperature conditions. Probiotic strains freeze-dried without substrate had the overall highest count reductions (0.5 ± 0.1 to 2.9 ± 0.3 log cycles) after freeze-drying. Probiotics freeze-dried with fruit processing coproducts had small cell subpopulations with damaged efflux activity and membrane potential. Average counts of probiotics freeze-dried with ACE, CAS, or GUA after 90 days of storage under refrigerated or room temperature were in the range of 4.2 ± 0.1 to 5.3 ± 0.2 and 2.6 ± 0.3 to 4.9 ± 0.2 log CFU/g, respectively, which were higher than those observed for strains freeze-dried without substrate. The greatest protective effects on freeze-dried probiotics were overall presented by ACE. These results revealed that ACE, CAS, and GUA can exert protective effects and increase the stability of probiotic lactobacilli during freeze-drying and storage, in addition to supporting a possible added-value destination for these agroindustrial coproducts as vehicles for probiotics and for the development of novel functional foods.

scholarly journals Freeze-Drying of Plant Tissue Containing HBV Surface Antigen for the Oral Vaccine against Hepatitis B

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Marcin Czyż ◽  
Radosław Dembczyński ◽  
Roman Marecik ◽  
Justyna Wojas-Turek ◽  
Magdalena Milczarek ◽  
...  
Keyword(s):  
Hepatitis B ◽  
Surface Antigen ◽  
Freeze Drying ◽  
Elevated Temperatures ◽  
Oral Vaccine ◽  
Leaf Tissue ◽  
Residual Moisture ◽  
Small Surface ◽  
Process Step ◽  
Freeze Dried

The aim of this study was to develop a freeze-drying protocol facilitating successful processing of plant material containing the small surface antigen of hepatitis B virus (S-HBsAg) while preserving its VLP structure and immunogenicity. Freeze-drying of the antigen in lettuce leaf tissue, without any isolation or purification step, was investigated. Each process step was consecutively evaluated and the best parameters were applied. Several drying profiles and excipients were tested. The profile of 20°C for 20 h for primary and 22°C for 2 h for secondary drying as well as sucrose expressed efficient stabilisation of S-HBsAg during freeze-drying. Freezing rate and postprocess residual moisture were also analysed as important factors affecting S-HBsAg preservation. The process was reproducible and provided a product with VLP content up to 200 µg/g DW. Assays for VLPs and total antigen together with animal immunisation trials confirmed preservation of antigenicity and immunogenicity of S-HBsAg in freeze-dried powder. Long-term stability tests revealed that the stored freeze-dried product was stable at 4°C for one year, but degraded at elevated temperatures. As a result, a basis for an efficient freeze-drying process has been established and a suitable semiproduct for oral plant-derived vaccine against HBV was obtained.

The effect of heat on the vitamin B6 of milk: II. A comparison of biological and microbiological tests of evaporated milk

1959 ◽  
Vol 26 (2) ◽  
pp. 215-220 ◽  
Author(s):  
Mary K. Davies ◽  
Margaret E. Gregory ◽  
Kathleen M. Henry
Keyword(s):  
Vitamin B6 ◽  
Experimental Error ◽  
Freeze Drying ◽  
Room Temperature ◽  
Raw Milk ◽  
Vitamin B ◽  
Experimental Conditions ◽  
Freeze Dried ◽  
Microbiological Research ◽  
Chick Diet

1. For chicks and rats pyridoxine, pyridoxal and pyridoxamine were equally active in terms of the free bases when given separately from the diet.2. Under our experimental conditions pyridoxine mixed with the chick diet was stable, but 20% of pyridoxamine, and a variable amount of pyridoxal was lost.3. The vitamin B6 activities measured with Saccharomyces carlsbergensis, chicks and rats respectively and expressed as μg. pyridoxine/g. freeze-dried milk were: raw milk 3·4, 3·2 and 4·9; evaporated milk 1·0, 2·1 and 2·7; stored evaporated milk 0·6, 1·4 and 2·0. For the chicks the milks were mixed with the diets; they were given separately to the rats.4. The microbiological and biological results for raw milk agreed within the limits of experimental error. For the processed milks the differences between biological and microbiological tests were statistically significant.5. All three methods of assay showed a 45–70% loss of vitamin B6 activity on processing and a further loss of 30% of the remainder after storage for 6 months at room temperature.We are indebted to Mr J. Rothwell, Department of Dairying, University of Reading, for preparing the evaporated milk and to Dr B. Record, Ministry of Supply, Microbiological Research Establishment, Porton, for freeze-drying the milk. We should like to thank Dr S. K. Kon for his interest in this work.

scholarly journals Freeze-dried plasma proteins are stable at room temperature for at least 1 year

2021 ◽  
Author(s):  
Jaimie Dufresne ◽  
Trung Hoang ◽  
Juliet Ajambo ◽  
Angelique Florentinus-Mefailoski ◽  
Peter Bowden ◽  
...  
Keyword(s):  
Liquid Nitrogen ◽  
Random Sampling ◽  
Freeze Drying ◽  
Room Temperature ◽  
Complement Component ◽  
Separate Experiment ◽  
Plasma Samples ◽  
Esi Ms ◽  
Freeze Dried ◽  
Edta Plasma

Thirty human EDTA plasma samples from male and female subjects ranging in age from 24 to 74 years were collected on ice, processed ice cold and stored frozen at −80 °C, in liquid nitrogen (LN2), or freeze dried and stored at room temperature in a desiccator (FDRT) or freeze dried and stored at −20 °C for 1 year (FD-20). In a separate experiment, EDTA plasma samples were collected onto ice, processed ice cold and maintained on ice ± protease inhibitors versus incubated at room temperature for up to 96 h. Random and independent sampling by liquid chromatography and tandem mass spectrometry (LC–ESI–MS/MS), as correlated by the MASCOT, OMSSA, X!TANDEM and SEQUEST algorithms, showed that tryptic peptides from complement component 4B (C4B) were rapidly released in plasma at room temperature. Random sampling by LC–ESI–MS/MS showed that peptides from C4B were undetectable on ice, but peptides were cleaved from the mature C4B protein including NGFKSHALQLNNR within as little as 1 h at room temperature. The frequency and intensity of precursors within ± 3 m/z of the C4B peptide NGFKSHALQLNNR was confirmed by automated targeted analysis where the precursors from MS/MS spectra that correlated to the target sequence were analyzed in SQL/R. The C4B preproprotein was processed at the N terminus to release the mature chain that was cleaved on the carboxyl side of the isoprene C2 domain within a polar C terminal sequence of the mature C4B protein, to reveal the thioester reaction site, consistent with LC–ESI–MS/MS and Western blot. Random sampling showed that proteolytic peptides from complement component C4B were rarely observed with long term storage at − 80 °C in a freezer or in liquid nitrogen (LN2), freeze drying with storage at − 20 °C (FD-20 °C) or freeze drying and storage at room temperature (FDRT). Plasma samples maintained at room temperature (RT) showed at least 10-fold to 100-fold greater frequency of peptide correlation to C4B and measured peptide intensity compared to samples on ice for up to 72 h or stored at − 80 °C, LN2, FDRT or FD-20 °C for up to a year.

scholarly journals Microwave-Assisted Freeze-Drying of Monoclonal Antibodies: Product Quality Aspects and Storage Stability

Pharmaceutics ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 674
Author(s):  
Julian Hendryk Gitter ◽  
Raimund Geidobler ◽  
Ingo Presser ◽  
Gerhard Winter
Keyword(s):  
Monoclonal Antibodies ◽  
Freeze Drying ◽  
Storage Stability ◽  
Moisture Distribution ◽  
General Applicability ◽  
Residual Moisture ◽  
Microwave Assisted ◽  
Freeze Dried ◽  
Quality Aspects ◽  
Related Quality

In order to overcome the downside of long conventional freeze-drying (CFD) process times for monoclonal antibody formulations, microwave-assisted freeze-drying (MFD) was introduced. Recently, the general applicability and potential shortening of drying times were shown. However, little is known about the storage stability of MFD products compared to CFD references. Additionally, batch homogeneity issues were seen within MFD in the past. In this study, we examined four different formulations of two different monoclonal antibodies using three different glass-forming excipients: sucrose, trehalose, and arginine phosphate. These formulations were freeze-dried with two different drying protocols (CFD and MFD), stored for 24 weeks, and analyzed for solid-state and protein-related quality attributes. Moreover, a new microwave generator setup was investigated for its potential to improve batch homogeneity. In all investigated formulations, comparable stability profiles were found, although the classical magnetron generator led to inferior batch homogeneity with respect to residual moisture distribution. In contrast, the new MFD setup indicated the potential to approximate batch homogeneity to the level of CFD. However, for future applications, there is an unabated need for new machine designs to comply with pharmaceutical manufacturing requirements.

scholarly journals Role of Calcium Alginate and Mannitol in Protecting Bifidobacterium

2012 ◽  
Vol 78 (19) ◽  
pp. 6914-6921 ◽  
Author(s):  
Dianawati Dianawati ◽  
Vijay Mishra ◽  
Nagendra P. Shah
Keyword(s):  
Freeze Drying ◽  
Room Temperature ◽  
Cell Envelope ◽  
Aluminum Foil ◽  
Alginate Beads ◽  
Content Type ◽  
Bifidobacterium Animalis ◽  
Freeze Dried ◽  
Cell Envelopes ◽  
Ca Alginate

ABSTRACTFourier transform infrared (FTIR) spectroscopy was carried out to ascertain the mechanism of Ca-alginate and mannitol protection of cell envelope components and secondary proteins ofBifidobacterium animalissubsp.lactisBb12 after freeze-drying and after 10 weeks of storage at room temperature (25°C) at low water activities (aw) of 0.07, 0.1, and 0.2. Preparation of Ca-alginate and Ca-alginate-mannitol as microencapsulants was carried out by dropping an alginate or alginate-mannitol emulsion containing bacteria using a burette into CaCl2solution to obtain Ca-alginate beads and Ca-alginate-mannitol beads, respectively. The wet beads were then freeze-dried. The awof freeze-dried beads was then adjusted to 0.07, 0.1, and 0.2 using saturated salt solutions; controls were prepared by keeping Ca-alginate and Ca-alginate-mannitol in aluminum foil without awadjustment. Mannitol in the Ca-alginate system interacted with cell envelopes during freeze-drying and during storage at low aws. In contrast, Ca-alginate protected cell envelopes after freeze-drying but not during 10-week storage. Unlike Ca-alginate, Ca-alginate-mannitol was effective in retarding the changes in secondary proteins during freeze-drying and during 10 weeks of storage at low aws. It appears that Ca-alginate-mannitol is more effective than Ca-alginate in preserving cell envelopes and proteins after freeze-drying and after 10 weeks of storage at room temperature (25°C).

scholarly journals Pengaruh Proses Freeze-Drying dan Penyimpanan pada Suhu Kamar terhadap Viabilitas dan Patogenisitas Plasma Nutfah Mikroba Pasteurella Multocida

2016 ◽  
Vol 12 (1) ◽  
pp. 40
Author(s):  
Siti Chotiah
Keyword(s):  
Freeze Drying ◽  
Room Temperature ◽  
Pasteurella Multocida ◽  
Culture Collection ◽  
Pathogenicity Test ◽  
Drying Process ◽  
Colony Forming Unit ◽  
Freeze Dried ◽  
Conservation Method ◽  
Preservation Medium

<p>The effect of freeze-drying process and preserving in a vacuum at room temperature against viability and pathogenicity of veterinary microbe germ plasma of Pasteuerella multocida BCC 2331 was investigated at Balitvet. The aim of this study was to find out the most effective and efficient conservation method. As much as 5,2 x 1011 colony forming unit (CFU)/ml of bacteria suspension in 7.5% glucose serum as the preservation medium being pathogenic in mice with LD50 of 9,8 CFU/ml was freeze dried then stored at room temperature (&amp;plusmn;27oC) until the study was completed. Viability and pathogenicity test were done immediately after the process, 1 and 2 months after storage. The results showed that there were viability decreases amounted 1,3 x 101 CFU/ml, 102 CFU/ml and 8,2 x l02 CFU/m1 due to the effects of the process, one month and two-month storage respectively. The decreases of pathogenicity on mice were shown by the increases of LD50 amounting log 1, log 2, and log 3 a day after the process, one month and two-month storage respectively.</p><p> </p><p><strong>Abstrak</strong></p><p>Pengaruh proses kering beku dan penyimpanan hasil proses pada suhu kamar 27oC terhadap viabilitas dan patogenisitas plasma nutfah mikroba veteriner telah dipelajari di Balitvet untuk menentukan cara pelestarian yang efektif dan efisien. Dalam kegiatan ini dipakai bakteri Pasteurella multocida koleksi Balitvet Culture Collection nomor koleksi B2331. Suspensi bakteri sebanyak 5,2 x l011 coloni forming unit (CFU)/ml dalam medium preservan 7,5% glukosa, serum dan bersifat patogen pada mencit dengan LD50 9,8 CFU/ml diproses kering beku, kemudian disimpan pada suhu kamar (+27oC) sampai penelitian selesai. Uji viabilitas dan patogenisitas dilakukan langsung setelah proses dan pada 1 serta 2 bulan setelah penyimpanan. Hasil penelitian menunjukkan terjadi penurunan viabilitas sebanyak 1,3 x 101 CFU, dan 8,2 x 102 CFU/ml masingmasing karena pengaruh proses, pengaruh penyimpanan selama 1 dan 2 bulan. Patogenisitas pada mencit menurun yang ditandai oleh adanya peningkatan LD50 sebanyak log 1, log 2, dan log 3 masing-masing 1 hari setelah proses, 1 dan 2 bulan setelah penyimpanan.</p>

scholarly journals Freeze-dried plasma proteins are stable at room temperature for at least 1 year

2021 ◽  
Author(s):  
Jaimie Dufresne ◽  
Trung Hoang ◽  
Juliet Ajambo ◽  
Angelique Florentinus-Mefailoski ◽  
Peter Bowden ◽  
...  
Keyword(s):  
Liquid Nitrogen ◽  
Random Sampling ◽  
Freeze Drying ◽  
Room Temperature ◽  
Complement Component ◽  
Separate Experiment ◽  
Plasma Samples ◽  
Esi Ms ◽  
Freeze Dried ◽  
Edta Plasma

Thirty human EDTA plasma samples from male and female subjects ranging in age from 24 to 74 years were collected on ice, processed ice cold and stored frozen at −80 °C, in liquid nitrogen (LN2), or freeze dried and stored at room temperature in a desiccator (FDRT) or freeze dried and stored at −20 °C for 1 year (FD-20). In a separate experiment, EDTA plasma samples were collected onto ice, processed ice cold and maintained on ice ± protease inhibitors versus incubated at room temperature for up to 96 h. Random and independent sampling by liquid chromatography and tandem mass spectrometry (LC–ESI–MS/MS), as correlated by the MASCOT, OMSSA, X!TANDEM and SEQUEST algorithms, showed that tryptic peptides from complement component 4B (C4B) were rapidly released in plasma at room temperature. Random sampling by LC–ESI–MS/MS showed that peptides from C4B were undetectable on ice, but peptides were cleaved from the mature C4B protein including NGFKSHALQLNNR within as little as 1 h at room temperature. The frequency and intensity of precursors within ± 3 m/z of the C4B peptide NGFKSHALQLNNR was confirmed by automated targeted analysis where the precursors from MS/MS spectra that correlated to the target sequence were analyzed in SQL/R. The C4B preproprotein was processed at the N terminus to release the mature chain that was cleaved on the carboxyl side of the isoprene C2 domain within a polar C terminal sequence of the mature C4B protein, to reveal the thioester reaction site, consistent with LC–ESI–MS/MS and Western blot. Random sampling showed that proteolytic peptides from complement component C4B were rarely observed with long term storage at − 80 °C in a freezer or in liquid nitrogen (LN2), freeze drying with storage at − 20 °C (FD-20 °C) or freeze drying and storage at room temperature (FDRT). Plasma samples maintained at room temperature (RT) showed at least 10-fold to 100-fold greater frequency of peptide correlation to C4B and measured peptide intensity compared to samples on ice for up to 72 h or stored at − 80 °C, LN2, FDRT or FD-20 °C for up to a year.

Sign in / Sign up

Export Citation Format

Share Document