Role of Hypoxia on Growth and Differentiation of Human Adipose Derived Stem Cells Grown on Silk Fibroin Scaffold Induced by Platelet Rich Plasma

Previous research has proven that 10% platelet-rich plasma (PRP) can enhance growth and differentiation of human adipose derived stem cells (hADSC) grown on silk fibroin scaffold into chondrocytes. A low oxygen concentration (hypoxia) condition is an important factor that potentially affects the ability of hADSC to grow and differentiate. The objective of this research was to analyze the difference in growth and differentiation capacity of hADSC grown on salt leached silk fibroin scaffold supplemented by 10% PRP under normoxic and hypoxic conditions. The growth capacity of the hADSC was determined by MTT assay and differentiation was tested using glycosaminoglycan (GAG) content analysis, while chondrocyte markers were visualized with the immunocytochemistry (ICC) method. This research observed hADSC proliferation under normoxic and hypoxic conditions for 21 days. Visualization of type 2 collagen showed that it was more abundant under hypoxia compared to normoxia. HIF-1α was only detected in the hADSC cultured in hypoxic conditions. In conclusion, culture under hypoxic conditions increases the capacity of hADSC to grow and differentiate into chondrocytes. This is the first study that has shown that hypoxia is able to enhance the proliferation and differentiation of hADSC grown on 3D salt leached silk fibroin scaffold supplemented by 10% PRP.

Discovery of nondiazotrophic Trichodesmium species abundant and widespread in the open ocean

Filamentous and colony-forming cells within the cyanobacterial genus Trichodesmium might account for nearly half of nitrogen fixation in the sunlit ocean, a critical mechanism that sustains plankton’s primary productivity. Trichodesmium has long been portrayed as a diazotrophic genus. By means of genome-resolved metagenomics, here we reveal that nondiazotrophic Trichodesmium species not only exist but also are abundant and widespread in the open ocean, benefiting from a previously overlooked functional lifestyle to expand the biogeography of this prominent marine genus. Near-complete environmental genomes for those closely related candidate species reproducibly shared functional features including a lack of genes related to nitrogen fixation, hydrogen recycling, and hopanoid lipid production concomitant with the enrichment of nitrogen assimilation genes. Our results elucidate fieldwork observations of Trichodesmium cells fixing carbon but not nitrogen. The Black Queen hypothesis and burden of low-oxygen concentration requirements provide a rationale to explain gene loss linked to nitrogen fixation among Trichodesmium species. Disconnecting taxonomic signal for this genus from a microbial community’s ability to fix nitrogen will help refine our understanding of the marine nitrogen balance. Finally, we are reminded that established links between taxonomic lineages and functional traits do not always hold true.

Identification and Functional Analysis of lncRNAs Responsive to Hypoxia in Eospalax fontanierii

Subterranean rodents could maintain their normal activities in hypoxic environments underground. Eospalax fontanierii, as one kind of subterranean rodent found in China can survive very low oxygen concentration in labs. It has been demonstrated that long non-coding RNAs (lncRNAs) have important roles in gene expression regulations at different levels and some lncRNAs were found as hypoxia-regulated lncRNAs in cancers. We predicted thousands of lncRNAs in the liver and heart tissues by analyzing RNA-Seq data in Eospalax fontanierii. Those lncRNAs often have shorter lengths, lower expression levels, and lower GC contents than mRNAs. Majors of lncRNAs have expression peaks in hypoxia conditions. We found 1128 DE-lncRNAs (differential expressed lncRNAs) responding to hypoxia. To search the miRNA regulation network for lncRNAs, we predicted 471 and 92 DE-lncRNAs acting as potential miRNA target and target mimics, respectively. We also predicted the functions of DE-lncRNAs based on the co-expression networks of lncRNA-mRNA. The DE-lncRNAs participated in the functions of biological regulation, signaling, development, oxoacid metabolic process, lipid metabolic/biosynthetic process, and catalytic activity. As the first study of lncRNAs in Eospalax fontanierii, our results show that lncRNAs are popular in transcriptome widely and can participate in multiple biological processes in hypoxia responses.

The Methods of Digging for “Gold” within the Salt: Characterization of Halophilic Prokaryotes and Identification of Their Valuable Biological Products Using Sequencing and Genome Mining Tools

Halophiles, the salt-loving organisms, have been investigated for at least a hundred years. They are found in all three domains of life, namely Archaea, Bacteria, and Eukarya, and occur in saline and hypersaline environments worldwide. They are already a valuable source of various biomolecules for biotechnological, pharmaceutical, cosmetological and industrial applications. In the present era of multidrug-resistant bacteria, cancer expansion, and extreme environmental pollution, the demand for new, effective compounds is higher and more urgent than ever before. Thus, the unique metabolism of halophilic microorganisms, their low nutritional requirements and their ability to adapt to harsh conditions (high salinity, high pressure and UV radiation, low oxygen concentration, hydrophobic conditions, extreme temperatures and pH, toxic compounds and heavy metals) make them promising candidates as a fruitful source of bioactive compounds. The main aim of this review is to highlight the nucleic acid sequencing experimental strategies used in halophile studies in concert with the presentation of recent examples of bioproducts and functions discovered in silico in the halophile’s genomes. We point out methodological gaps and solutions based on in silico methods that are helpful in the identification of valuable bioproducts synthesized by halophiles. We also show the potential of an increasing number of publicly available genomic and metagenomic data for halophilic organisms that can be analysed to identify such new bioproducts and their producers.

High-Sustained Concentrations of Organisms at Very low Oxygen Concentration Indicated by Acoustic Profiles in the Oxygen Deficit Region Off Peru

The oxygen deficient mesopelagic layer (ODL) off Peru has concentrations below 5 μmol O2 kg–1 and is delimited by a shallow upper oxycline with strong vertical gradient and a more gradual lower oxycline (lOx). Some regions show a narrow band of slightly increased oxygen concentrations within the ODL, an intermediate oxygen layer (iO2). CTD, oxygen and lowered Acoustic Doppler Current Profiler (LADCP, 300 kHz) profiles were taken on the shelf edge and outside down to mostly 2000 m. We evaluate here the acoustic volume backscatter strength of the LADCP signal representing organisms of about 5 mm size. Dominant features of the backscatter profiles were a minimum backscatter strength within the ODL, and just below the lOx a marked backscatter increase reaching a maximum at less than 3.0 μmol O2 kg–1. Below this maximum, the acoustic backscatter strength gradually decreased down to 1000 m below the lOx. The backscatter strength also increased at the iO2 in parallel to the oxygen concentration perturbations marking the iO2. These stable backscatter features were independent of the time of day and the organisms represented by the backscatter had to be adapted to live in this microaerobic environment. During daylight, these stable structures were overlapped by migrating backscatter peaks. Outstanding features of the stable backscatter were that at very low oxygen concentrations, the volume backscatter was linearly related to the oxygen concentration, reaching half peak maximum at less than 2.0 μmol O2 kg–1 below the lOx, and the depth-integrated backscatter of the peak below the lOx was higher than the integral above the Ox. Both features suggest that sufficient organic material produced at the surface reaches to below the ODL to sustain the major fraction of the volume backscatter-producing organisms in the water column. These organisms are adapted to the microaerobic environment so they can position themselves close to the lower oxycline to take advantage of the organic particles sinking out of the ODL.

Evaluation of the quality of embryo based on morphology cultured at low oxygen concentration

Objectives: evaluating the quality of embryo morphology cultured at low oxygen concentration (5%) at different stages of embryonic development: day 3, day 5. Methods: the present study examined 168 IVF/ICSI cycles from October 2019 to February 2021 at the Assisted Reproductive Center, 16A Ha Dong General Hospital. Embryos were randomly assigned to 2 groups: group 1 used a K-system G-210 tri-gas incubator (Australia) (5% O2, 5% CO2, 90% N2) while group 2 used a Thermo Scientific 371 dual-gas incubator (Denmark) (5% CO2, 75% N2 with 20% atmospheric Oxygen concentration). Participants in the study were patients younger than 37 years old, with AMH>1.2 ng/ml, and AFC≥4. Mature oocytes were injected with sperm, and cultured in a sequential medium (G1,G2-PLUSTM). Embryologists assessed embryos on the day of fertilisation, days 3, 5, and compared the results of the two groups, using the method of descriptive statistics and T-test. The results revealed an insignificant difference in fertilisation rate and the quality of cleavages cultured in these 2 groups (percentages of good- and average quality cleavages were, in turn, 77.28±4.62% và 77.99±5.03%, at p>0.05, number of poor quality cleavages were, in turn, 1.71±0.38 vs 1.97±0.49 with p>0.05). The results on day 5 embryo showed that the percentage of blastocysts (from fertilisation) and the percentage of morphologically good- and average-quality blastocysts tended to increase higher when cultured in 5% oxygen concentration (p<0.05) compared with the 20% one (57.79±3.60% and 53.05±4.50%, 78.62±4.42% and 70.97±5.67%, respectively). Conclusions: embryo cultured in a low oxygen concentration helps embryos develop better on day 5 than when cultured at atmospheric concentrations

State and prospects of hygienic regulation of the production environment with a reduced oxygen content (literature review)

The work is devoted to the physiological and hygienic foundations of the safety of activities in the conditions of the changed gas environment and characteristics of the main medical measures for the employees’ protection in a hypoxic environment, the analysis of domestic and foreign data, the study of working conditions in the environment with the reduced oxygen concentration in the air. Investigations were carried out on premises with various technological processes, a changing environment, and a reduced oxygen concentration when employees perform multiple operations. The health status of workers was assessed depending on the time spent in the changed gas environment and the percentage of oxygen. Having analyzed the regulatory documents currently existing in the Russian Federation on the assessment and control of production factors, working conditions in confined spaces with a low oxygen concentration in the air, air environment to maintain health, high performance, and prevent diseases, experts concluded that it is necessary to develop Sanitary Rules and Norms, SanPiN “Sanitary and Epidemiological Requirements for Habitability (Stay) in Confined Spaces with a Low Oxygen Concentration in the Air” because currently there is no document existing specifically on this issue. The literature was searched in the databases Scopus, Web of Science, MedLine, The Cochrane Library, EMBASE, Global Health, CyberLeninka, RSCI. There were prepared draft sanitary plans and standards “Sanitary and epidemiological requirements for the environment with a reduced concentration of oxygen in the air,” which establish sanitary and epidemiological requirements for the environment with a reduced concentration of oxygen in the air, as well as for the organization of control, methods measurements of air components at workplaces and measures to prevent harmful effects on the health of workers. They apply to work conditions in the living environment for all premises with a reduced oxygen concentration in the air.