Epigenetic regulation in the commitment of progenitor cells during retinal development and regeneration.

Retinal development is initiated by multipotent retinal progenitor cells, which undergo several rounds of cell divisions and subsequently terminal differentiation. Retinal regeneration is usually considered as the recapitulation of retinal development, which share common mechanisms underlying the cell cycle re-entry of adult retinal stem cells and the differentiation of retinal neurons. However, how proliferative retinal progenitor cells perform a precise transition to postmitotic retinal cell types during the process of development and regeneration remains elusive. It is proposed that both the intrinsic and extrinsic programming are involved in the transcriptional regulation of the spatio-temporal fate commitment. Epigenetic modifications and the regulatory mechanisms at both DNA and chromatin levels are also postulated to play an important role in the timing of differentiation of specific retinal cells. In the present review, we have summarized recent knowledge of epigenetic regulation that underlies the commitment of retinal progenitor cells in the settings of retinal development and regeneration.

The Role of Adaptive Immunity in Diabetic Retinopathy.

Diabetic retinopathy (DR) is currently one of the common causes of vision loss in working-age adults. It is clinically diagnosed and classified according to the vascular changes in the fundus. However, the activation of immune cells occurs before these vascular changes become detectable. These, together with molecular studies and the positive clinical outcomes of anti-inflammatory treatment, highlight the pivotal involvement of the immune system. The role of innate immunity in DR pathophysiology has been studied in depth, but the contribution of adaptive immunity remains largely elusive. This review aims to summarize our current understanding of the activation mechanism of adaptive immunity in DR microenvironments and to discuss the relationship between adaptive immunity and local vascular units or innate immunity, which opens new avenues for clinical applications in DR treatment.

Promotion and mechanisms of Bdellovibrio sp. Y38 on membrane fouling alleviation in membrane bioreactor.

Membrane fouling is a major bottleneck limiting the widespread application of membrane bioreactors (MBR). In this study, Bdellovibrio sp. Y38, an obligate bacteriophage bacterium of Bdellovibrio-and-like organisms (BALOs), was enriched into highly concentrated culture medium (106-107 PFU/mL), and daily dosed into the MBR to investigate its effects on membrane fouling mitigation. The strain Y38 prolonged the membrane fouling cycle from 73 days to 90 days, indicating its membrane fouling alleviation potentials. The concentration of BALOs was increased 625 times higher than the control group after the whole operation, resulting in the concentration of chemical oxygen demand and nucleic acids in the liquid phase of the MBR system being significantly increased by 169.8 ± 1.5% and 126.7 ± 2.2%, respectively. The biomass growth rate was reduced by 27.2 ± 0.7% from day 0 to day 54. These results indicated the predation potential of Bdellovibrio sp. Y38 on the microorganisms in the sludge. The improvement of homogenized sludge and filtration and settling performance by the strain Y38 alleviated the membrane fouling. Compared with the control group, the macromolecular proteins in SMP and EPS were partially declined, and the polysaccharide in EPS decreased by 14.0 ± 3.9%, and the ratios of protein content to polysaccharide content (PN/PS) in SMP and EPS significantly increased by 35.6 ± 16.8% and 57.8 ± 6.1% at the middle stage, respectively, indicating the strain Y38 could alleviate membrane fouling by reducing and modifying SMP and EPS. Furthermore, the relative abundance of γ-proteobacteria decreased from 13.2% to 5.1% at the pre-middle stage, and Planctomycetes decreased from 1.5% to 0.8% at the end-stage, which were probably responsible for the membrane fouling mitigation. In addition, the strain Y38 had few impacts on the water treatment performance of MBR. There findings provide a promising strategy for in situ membrane pollution mitigation via exogenous additions of BALOs.

Somatostatin signalling promotes the differentiation of rod photoreceptors in human pluripotent stem cell-derived retinal organoid.

OBJECTIVES: Stem cell-derived photoreceptor replacement therapy is a promising strategy for the treatment of retinal degenerative disease. The development of 3D retinal organoids has permitted the production of photoreceptors. However, there is no strategy to enrich a specific photoreceptor subtype due to inadequate knowledge of the molecular mechanism underlying the photoreceptor fate determination. Hence, our aim is to explore the uncharacterized function of somatostatin signalling in human pluripotent stem cell-derived photoreceptor differentiation. MATERIALS AND METHODS: 3D retinal organoids were achieved from human embryonic stem cell. The published single-cell RNA-sequencing datasets of human retinal development were utilized to further investigate the transcriptional regulation of photoreceptor differentiation. The assays of immunofluorescence staining, lentivirus transfection, real-time quantitative polymerase chain reaction and western blotting were performed. RESULTS: We identified that the somatostatin receptor 2 (SSTR2)-mediated signalling was essential for rod photoreceptor differentiation at the precursor stage. The addition of the cognate ligand somatostatin in human 3D retinal organoids promoted rod photoreceptor differentiation and inhibited cone photoreceptor production. Furthermore, we found that the genesis of rod photoreceptors was modulated by endogenous somatostatin specifically secreted by developing retinal ganglion cells. CONCLUSIONS: Our study identified SSTR2 signalling as a novel extrinsic regulator for rod photoreceptor fate determination in photoreceptor precursors, which expands the repertoire of functional signalling pathways in photoreceptor development and sheds light on the optimization of the photoreceptor enrichment strategy.

Visual Analysis of Research Hotspots in Geriatric Nursing Education in China and Abroad.

Background: This study aimed to conduct a literature search to determine research hotspots in the field of gerontological care education in China and abroad. A knowledge of the focus of research conducted abroad may assist Chinese educators in determining the shape of gerontological care education in the future. Methods: The "Web of Science Core Collection" and "CNKI" databases were searched for literature on gerontological care education published from 2010 to 2020. CiteSpace software was used to display the knowledge map of co-occurrence of keywords, and an evolution trend map of research hotspots in recent 10 years was constructed. Results: From 2010 to 2020, the focus of foreign gerontological nursing education research was on the training of gerontological nursing personnel; the development of elderly care services; and education and training in dealing with patients with senile delirium and dementia. The focus of gerontological nursing education research in China was primary care education, training of senior elderly nursing personnel, talent training mode reform, training of nursing staff, and career development paths for geriatric nursing staff. Conclusions: Foreign geriatric nursing education research focuses on cultivating talents, mental health services for the elderly, innovating the mode of pension, and the care of patients with disorders such as dementia and delirium, while in China, the emphasis remains on gerontological nursing personnel training. Attention to research developments in other countries may assist Chinese educators to promote the development of geriatric nursing education in our country.

Cognitive frailty as a predictor of adverse outcomes among older adults: A systematic review and meta-analysis.

OBJECTIVE: A systematic review and meta-analysis basing on the prospective cohort studies were conducted to explore the risk of all-cause mortality and dementia in cognitively frail older adults compared to robust older adults and to determine whether it was a predictor of adverse outcomes. METHODS: Pubmed, Web of Science, The Cochrane Library, EMBASE, and CINAHL databases were searched to retrieve studies on adverse outcomes of cognitive frailty. Two reviewers independently screened the literature, extracted data, and assessed the risk of bias of the included studies. Stata 15.0 Software was used to perform the meta-analysis. The all-cause mortality and dementia were observed to be the primary outcomes, while the other data were considered as the secondary outcome. RESULTS: A total of 14 studies were included in qualitative analysis and 12 studies were included in the meta-analysis, with low risk of bias and moderate to good methodological quality. The results showed that cognitive frailty in older people had a higher risk of all-cause mortality [HR = 1.93, 95%CI (1.67, 2.23), p < .001] and dementia [HR = 3.66, 95%CI (2.86, 4.70) as compared with robust. The subgroup analysis showed that the assessment tools were the main source of heterogeneity. CONCLUSION: In older adults living in communities, the cognitive frailty was found to be a significant predictor of all-cause mortality and dementia. Nonetheless, cognitive frailty was found to be a better predictor of all-cause mortality and dementia than just frailty.

Aging forming process of Chlorella vulgaris growing medium and its cultivation inhibition mechanism.

To investigate the possibility of culture medium reuse in large-scale industrial microalgae cultivation for the alleviation of the massive water requirement pressure, the aging forming process of Chlorella vulgaris growing medium was explored and the aged medium's inhibition mechanisms on cell growth were inspected. The results demonstrated that when the medium was continuously reused, the collected maximal C. vulgaris biomass decreased. After the fourth medium reuse, the maximal biomass concentration was only 55 ± 1.1% of that in the fresh medium, which indicated the gradual aging of the medium. Furthermore, the composition variation of the released organic secretions during the culture medium reuse was monitored and the results showed that high concentrations of fatty acids (FAs), including palmitic acid, stearic acid, and small amounts of polysaccharides, were accumulated. Further investigation indicated that the obtained maximal biomass of C. vulgaris has a negative relationship with the manually added initial FA concentrations in the medium which suggested that the accumulated FAs in the medium probably were the main C. vulgaris growth inhibition factor. The inhibition effect of FAs on C. vulgaris was mainly achieved via impacting the cells' photosynthesis efficiencies to destroy the intracellular antioxidant system.

[Assessing Performance of Pollutant Removal from Municipal Wastewater by Physical and Chemical Methods Based on Membranes].

The removal characteristics of various pollution factors in municipal wastewater by membrane-based physical and chemical treatment, especially the enrichment characteristics of dissolved organic matter, were investigated by high performance liquid chromatography and three-dimensional fluorescence spectroscopy. The results showed that the municipal wastewater had a low COD/TN ratio after the treatment. The micro-flocculation filtration mainly enriched the non-dissolvable organic matter in the raw water and aromatic protein substances with relative molecular mass greater than 30 000. The enrichment degree was up to 60.93%, especially for tyrosine-like and tryptophan-like substances. The dissolved organic matter (DOM) with a molecular weight greater than 30 000 was enriched fully by 0.45 µm and 0.22 µm acetate membranes, but the microfiltration membrane was not selective for the enrichment of organic matter. Thus, NF mainly enriched the fulvic acid and humic acid in urban sewage. The enrichment degree was 52.01% and 53.57%, respectively, and the total enrichment degree of dissolved organic matter was about 42%.