High DNA stability in white blood cells and buffy coat lysates stored at ambient temperature under anoxic and anhydrous atmosphere

Reviving vacuum-dried encapsulated ram spermatozoa via ICSI after 2 years of storage

Introduction

Freeze-drying techniques give alternative preservation mammalian spermatozoa without liquid nitrogen. However, most of the work has been conducted in the laboratory mouse, while little information has been gathered on large animals that could also benefit from this kind of storage.

Methods

This work adapted a technique known as vacuum-drying encapsulation (VDE), originally developed for nucleic acid conservation in anhydrous state, to ram spermatozoa, and compared it to canonical lyophilization (FD), testing long-term storage at room temperature (RT) and 4°C.

Results and discussion

The results demonstrated better structural stability, namely lipid composition and DNA integrity, in VDE spermatozoa than FD ones, with outcomes at RT storage comparable to 4°C. Likewise, in VDE the embryonic development was higher than in FD samples (12.8% vs. 8.7%, p < 0.001, respectively). Our findings indicated that in large mammals, it is important to consider dehydration-related changes in sperm polyunsaturated fatty acids coupled with DNA alterations, given their crucial role in embryonic development.

Relationship Between Amplicon Size and Heat Conditions in Polymerase Chain Reaction Detection of DNA Degraded by Autoclaving

This study examined the influence of heat exposure on DNA samples during polymerase chain reaction (PCR) detection. In this study, λDNA samples, as model DNA, were exposed to 105°C for 3-90 minutes or to 105°C-115°C for 15 minutes by autoclaving. The exposed samples were subjected to real-time PCR using nine primer sets with amplicon sizes of 45-504 bp. Regarding DNA samples exposed to 105°C by autoclaving, the data showed negative correlations between the logarithm of λDNA concentration (log λDNA) calculated using real-time PCR and exposure duration and a good relationship between the slope of the regression line and amplicon size. Regarding λDNA samples exposed to heat for 15 minutes, the data showed negative correlations between the log λDNA and exposure temperature and a good relationship between the slope of the regression line and amplicon size. These results showed that the equations used in this study could predict the degree of degradation in λDNA samples by autoclaving, and the PCR detection levels of the DNA at each amplicon size.

Emerging Approaches to DNA Data Storage: Challenges and Prospects

With the total amount of worldwide data skyrocketing, the global data storage demand is predicted to grow to 1.75 × 10¹⁴ GB by 2025. Traditional storage methods have difficulties keeping pace given that current storage media have a maximum density of 10³ GB/mm³. As such, data production will far exceed the capacity of currently available storage methods. The costs of maintaining and transferring data, as well as the limited lifespans and significant data losses associated with current technologies also demand advanced solutions for information storage. Nature offers a powerful alternative through the storage of information that defines living organisms in unique orders of four bases (A, T, C, G) located in molecules called deoxyribonucleic acid (DNA). DNA molecules as information carriers have many advantages over traditional storage media. Their high storage density, potentially low maintenance cost, ease of synthesis, and chemical modification make them an ideal alternative for information storage. To this end, rapid progress has been made over the past decade by exploiting user-defined DNA materials to encode information. In this review, we discuss the most recent advances of DNA-based data storage with a major focus on the challenges that remain in this promising field, including the current intrinsic low speed in data writing and reading and the high cost per byte stored. Alternatively, data storage relying on DNA nanostructures (as opposed to DNA sequence) as well as on other combinations of nanomaterials and biomolecules are proposed with promising technological and economic advantages. In summarizing the advances that have been made and underlining the challenges that remain, we provide a roadmap for the ongoing research in this rapidly growing field, which will enable the development of technological solutions to the global demand for superior storage methodologies.

Long term conservation of DNA at ambient temperature. Implications for DNA data storage

DNA conservation is central to many applications. This leads to an ever-increasing number of samples which are more and more difficult and costly to store or transport. A way to alleviate this problem is to develop procedures for storing samples at room temperature while maintaining their stability. A variety of commercial systems have been proposed but they fail to completely protect DNA from deleterious factors, mainly water. On the other side, Imagene company has developed a procedure for long-term conservation of biospecimen at room temperature based on the confinement of the samples under an anhydrous and anoxic atmosphere maintained inside hermetic capsules. The procedure has been validated by us and others for purified RNA, and for DNA in buffy coat or white blood cells lysates, but a precise determination of purified DNA stability is still lacking. We used the Arrhenius law to determine the DNA degradation rate at room temperature. We found that extrapolation to 25°C gave a degradation rate constant equivalent to about 1 cut/century/100 000 nucleotides, a stability several orders of magnitude larger than the current commercialized processes. Such a stability is fundamental for many applications such as the preservation of very large DNA molecules (particularly interesting in the context of genome sequencing) or oligonucleotides for DNA data storage. Capsules are also well suited for this latter application because of their high capacity. One can calculate that the 64 zettabytes of data produced in 2020 could be stored, standalone, for centuries, in about 20 kg of capsules.

Autologous Biological Vitamin-C-added (ABC) Filler for Facial Volume Restoration

PURPOSE

Face rejuvenation procedures with injectable agents continue to gain popularity. Nowadays, a variety of commercial products are available as filler material. Ideal fillers should be inexpensive, easily obtainable, nontoxic, and biocompatible. The aim of this study is to report a clinical perspective for an appropriate, feasible, and inexpensive protocol of a stable, autologous biological filler for facial volume restoring without any commercial kits.

METHODS

Eight patients were investigated who underwent facial injection with ABC filler. Eleven ml of whole blood was placed in standard tubes containing anticoagulant and for each patient, 8 tubes were prepared. After the centrifugation at 1630 xg for 5 minutes, the upper plasma was taken, calcium was added and cooled. After the addition of vitamin C, the syringes were incubated at 85 °C for 10 minutes. The autologous biological material obtained was used as filling material. For comparison, FACE-Q satisfaction questionnaires were used before and after the procedure.

RESULTS

All patients were followed up for a minimum of 4 months. No major complications were recorded. The patient-reported FACE-Q satisfaction and FACE-Q quality of life pre- and post-procedure results showed statistically significant improvement (p  <  0.05). Overall satisfaction with the outcome was 89.12 ± 16.73 (range 55-100).

CONCLUSIONS

ABC filler can be seen as a reliable, inexpensive, and easily obtainable material to restore facial volume with increased patient satisfaction and quality of life scores. We believe that our study will be encouraging to the application of autologous biological fillers for further clinical and scientific studies.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

An Empirical Comparison of Preservation Methods for Synthetic DNA Data Storage

Synthetic DNA has recently risen as a viable alternative for long-term digital data storage. To ensure that information is safely recovered after storage, it is essential to appropriately preserve the physical DNA molecules encoding the data. While preservation of biological DNA has been studied previously, synthetic DNA differs in that it is typically much shorter in length, it has different sequence profiles with fewer, if any, repeats (or homopolymers), and it has different contaminants. In this paper, nine different methods used to preserve data files encoded in synthetic DNA are evaluated by accelerated aging of nearly 29 000 DNA sequences. In addition to a molecular count comparison, the DNA is also sequenced and analyzed after aging. These findings show that errors and erasures are stochastic and show no practical distribution difference between preservation methods. Finally, the physical density of these methods is compared and a stability versus density trade-offs discussion provided.

Preservation of DNA for data storage

The preservation of DNA has attracted significant interest of scientists in diverse research fields from ancient biological remains to the information field. In light of the different DNA safekeeping requirements (e.g., storage time, storage conditions) in these disparate fields, scientists have proposed distinct methods to maintain the DNA integrity. Specifically, DNA data storage is an emerging research, which means that the binary digital information is converted to the sequences of nucleotides leading to dense and durable data storage in the form of synthesized DNA. The intact preservation of DNA plays a significant role because it is closely related to data integrity. This review discusses DNA preservation methods, aiming to confirm an appropriate one for synthetic oligonucleotides in DNA data storage. First, we analyze the impact factors of the DNA long-term storage, including the intrinsic stability of DNA, environmental factors, and storage methods. Then, the benefits and disadvantages of diverse conservation approaches (e.g., encapsulation-free, chemical encapsulation) are discussed. Finally, we provide advice for storing non-genetic information in DNA in vitro. We expect these preservation suggestions to promote further research that may extend the DNA storage time.

The bibliography includes 99 references.

Real-Time Temperature Mapping in Ultra-Low Freezers as a Standard Quality Assessment

Adequate preservation of biospecimens has been proven to be critical to obtain reliable and reproducible results in genomics, transcriptomics, proteomics, and many other assays. Most biological assays can be performed on specimens preserved in -80°C ultra-low freezers, but their quality can be influenced by temperature variability within storage units. Thus, regulatory standards such as those from the College of American Pathologists (CAP), the federal Clinical Laboratory Improvement Amendments, and standards from the Food and Drug Administration require temperature mapping, a standard quality assessment for accreditation when using ultra-low freezers for long-term biospecimen storage. The current mapping methods, providing annual/periodic data, may not be adequate indicators of temperature stability within the different zones of the freezers. In addition, they frequently require manual handling of biospecimens periodically, as they require freezers to be emptied or rearranged temporarily for the installation of temperature probes, risking the integrity of biospecimen quality. In this article, we describe a novel monitoring methodology based on real-time temperature reading of multiple zones by permanently installing thermocouples. An online cloud-based application records temperature variations within 1 minute intervals, and its 24/7 alert system triggers text alarm messages to a predefined set of users when temperature values increase above preset defaults. This provides an opportunity to take remedial action and to obtain a better-quality assessment. Our results indicate that real-time temperature monitoring at multiple zones of a freezer with a 1 minute resolution is a stable and sustainable methodology and, most importantly, lowers the risk of compromising the quality of the biospecimen. The design and use of the real-time monitoring system for ultra-low freezers is one of the acceptable methods by CAP to ensure the stability of biospecimen quality during long-term storage.