Engineering Cyanobacterial Cell Factories for Photosynthetic Production of Fructose.

Fructose is an important monosaccharide product widely applied in the food, medicine, and chemical industries. Currently, fructose is mainly manufactured with plant biomass-sourced polysaccharides through multiple steps of digestion, conversion, separation, and purification. The development of cyanobacterial metabolic engineering provides an attractive alternative route for the one-step direct production of fructose utilizing carbon dioxide and solar energy. In this work, we developed a paradigm for engineering cyanobacterial chassis cells into efficient cell factories for the photosynthetic production of fructose. In a representative cyanobacterial strain, Synechococcus elongatus PCC 7942, knockout of fructokinase effectively activated the synthesis and secretion of fructose in hypersaline conditions, independent of any heterologous transporters. The native sucrose synthesis pathway was identified as playing a primary role in fructose synthesis. Through combinatory optimizations on the levels of metabolism, physiology, and cultivation, the fructose yield of the Synechococcus cell factories was stepwise improved to 3.9 g/L. Such a paradigm was also adopted to engineer another Synechococcus strain, the marine species Synechococcus sp. PCC 7002, and facilitated an even higher fructose yield of over 6 g/L. Finally, the fructose synthesized and secreted by the cyanobacterial photosynthetic cell factories was successfully extracted and prepared from the culture broth in the form of products with 86% purity through multistep separation-purification operations. This work demonstrated a paradigm for systematically engineering cyanobacteria for photosynthetic production of desired metabolites, and it also confirmed the feasibility and potential of cyanobacterial photosynthetic biomanufacturing as a simple and efficient route for fructose production.

Face Blindness in Children and Current Interventions.

Children with prosopagnosia, also known as face blindness, struggle to recognize the faces of acquaintances, which can have a negative impact on their social interactions and overall functioning. This paper reviews existing research on interventions for children with prosopagnosia, including compensatory and remedial strategies, and provides a summary and comparison of their effectiveness. However, despite the availability of these interventions, their effectiveness remains limited and constrained by various factors. The lack of a widely accepted treatment for children with prosopagnosia emphasizes the need for further research to improve intervention strategies. Last, three future research directions were proposed to improve interventions for prosopagnosia, including ecological approaches, the social challenges faced by children, and new potential intervention methods.

Unlocking the potentials of cyanobacterial photosynthesis for directly converting carbon dioxide into glucose.

Glucose is the most abundant monosaccharide, serving as an essential energy source for cells in all domains of life and as an important feedstock for the biorefinery industry. The plant-biomass-sugar route dominates the current glucose supply, while the direct conversion of carbon dioxide into glucose through photosynthesis is not well studied. Here, we show that the potential of Synechococcus elongatus PCC 7942 for photosynthetic glucose production can be unlocked by preventing native glucokinase activity. Knocking out two glucokinase genes causes intracellular accumulation of glucose and promotes the formation of a spontaneous mutation in the genome, which eventually leads to glucose secretion. Without heterologous catalysis or transportation genes, glucokinase deficiency and spontaneous genomic mutation lead to a glucose secretion of 1.5 g/L, which is further increased to 5 g/L through metabolic and cultivation engineering. These findings underline the cyanobacterial metabolism plasticities and demonstrate their applications for supporting the direct photosynthetic production of glucose.

Engineering cyanobacteria for converting carbon dioxide into isomaltulose.

Isomaltulose is a promising functional sweetener with broad application prospects in the food industry. Currently, isomaltulose is mainly produced through bioconversion processes based on the isomerization of sucrose, the economic feasibility of which is influenced by the cost of sucrose feedstocks, the biocatalyst preparation, and product purification. Cyanobacterial photosynthetic production utilizing solar energy and carbon dioxide represents a promising route for the supply of sugar products, which can promote both carbon reduction and green production. Previously, some cyanobacteria strains have been successfully engineered for synthesis of sucrose, the main feedstock for isomaltulose production. In this work, we introduced different sucrose isomerases into Synechococcus elongatus PCC 7942 and successfully achieved the isomaltulose synthesis and accumulation in the recombinant strains. Combinatory expression of an Escherichia coli sourced sucrose permease CscB with the sucrose isomerases led to efficient secretion of isomaltulose and significantly elevated the final titer. During a 6-day cultivation, 777 mg/L of isomaltulose was produced by the engineered Synechococcus cell factory. This work demonstrated a new route for isomaltulose biosynthesis utilizing carbon dioxide as the substrate, and provided novel understandings for the plasticity of cyanobacterial photosynthetic metabolism network.

Manipulating the Expression of Glycogen Phosphorylase in Synechococcus elongatus PCC 7942 to Mobilize Glycogen Storage for Sucrose Synthesis.

Cyanobacteria are a promising photosynthetic chassis to produce biofuels, biochemicals, and pharmaceuticals at the expense of CO2 and light energy. Glycogen accumulation represents a universal carbon sink mechanism among cyanobacteria, storing excess carbon and energy from photosynthesis and may compete with product synthesis. Therefore, the glycogen synthesis pathway is often targeted to increase cyanobacterial production of desired carbon-based products. However, these manipulations caused severe physiological and metabolic impairments and often failed to optimize the overall performance of photosynthetic production. Here, in this work, we explored to mobilize the glycogen storage by strengthening glycogen degradation activities. In Synechococcus elongatus PCC 7942, we manipulated the abundances of glycogen phosphorylase (GlgP) with a theophylline dose-responsive riboswitch approach, which holds control over the cyanobacterial glycogen degradation process and successfully regulated the glycogen contents in the recombinant strain. Taking sucrose synthesis as a model, we explored the effects of enhanced glycogen degradation on sucrose production and glycogen storage. It is confirmed that under non-hypersaline conditions, the overexpressed glgP facilitated the effective mobilization of glycogen storage and resulted in increased secretory sucrose production. The findings in this work provided fresh insights into the area of cyanobacteria glycogen metabolism engineering and would inspire the development of novel metabolic engineering approaches for efficient photosynthetic biosynthesis.

Synergistic Effect Between Full-Term Pregnancy/Breastfeeding And Familial Susceptibility On Breast Cancer Risk.

BACKGROUND: Breast cancer is the most common cancer in women worldwide, and reproductive factors and family history of malignancy are considered as high risk factors. The present study aimed to evaluate the synergistic effect of reproductive factors and family history on breast cancer. METHOD: A total of 1215 breast cancer patients and 1215 control participants from two medical centers were enrolled, and reproductive factor history and family cancer history information was collected. Multivariate logistic regression analyses were performed to estimate the adjusted odds ratio (OR), and synergy index (SI) was used to assess the combined effect of potential factors. RESULTS: Compared to the controls, a negative association between full-term pregnancy/breastfeeding and breast cancer was observed regardless of the status of family cancer history (OR: 0.675, 95% CI: 0.560-0.814 and OR: 0.631, 95% CI: 0.503-0.789 respectively) after adjustment of other confounders, while the risk effect of abortion was unproven. The synergistic effect of history of full-term pregnancy and family history of malignancy was indicated in the combined analyses with SI as 9.429 (95% CI:1.248-71.245). CONCLUSION: Full-term pregnancy/breastfeeding were protective factors against breast cancer and synergistic additive effect was demonstrated between no full-term pregnancy/breastfeeding and a family history of malignancy on the risk of breast cancer.

Induced Expression of VEGFC, ANGPT, and EFNB2 and Their Receptors Characterizes Neovascularization in Proliferative Diabetic Retinopathy.

Purpose: To investigate whole transcriptional differences between proliferative diabetic retinopathy (PDR) neovascular membranes (NVMs) and retinas, and the regulatory genes participating in retinal neovascularization in PDR. Methods: We used high-throughput sequencing technology to capture the whole-genome gene expression levels of all participants, including 23 patients with PDR or branch retinal vein occlusion (BRVO), 3 normal retinal samples, and 2 retinal samples from type II diabetic (T2D) eyes by donation, followed by analyses of expression patterns using bioinformatics methods, then validation of the data by in situ hybridization and Western blotting. Results: We showed that transcriptional profiles of the NVMs were distinct from those of the retinas. Angiogenesis growth factors VEGFC, ANGPT1, ANGPT2, and EFNB2, and their receptors FLT4, TIE1, TIE2, and EPHB4, respectively, were overexpressed. Expression of VEGFA was highly upregulated in T2D retina, but low in the NVMs, while angiogenesis transcription factors, including ETS1 and ERG, were coordinately upregulated in NVMs. Conclusions: This study described a PDR neovascularization model in which pathological retina-secreted vascular endothelial growth factor A (VEGFA) enhanced the expression of a set of angiogenesis transcription factors and growth factors, to cooperatively induce the retinal neovascularization. Based on these results, novel potential therapeutic targets and biomarkers for PDR treatment and diagnosis are suggested.

Ginkgolide A Ameliorates LPS-Induced Inflammatory Responses In Vitro and In Vivo.

Ginkgolide A (GA) is a natural compound isolated from Ginkgo biloba and has been used to treat cardiovascular diseases and diabetic vascular complications. However, only a few studies have been conducted on the anti-inflammatory effects of GA. In particular, no related reports have been published in a common inflammation model of lipopolysaccharide (LPS)-stimulated macrophages, and the anti-inflammatory mechanisms of GA have not been fully elucidated. In the present study, we extensively investigated the anti-inflammatory potential of GA in vitro and in vivo. We showed that GA could suppress the expression of pro-inflammatory mediators (cyclooxygenase-2 (COX-2) and nitric oxide (NO) and pro-inflammatory cytokines (tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-1ß) in LPS-treated mouse peritoneal macrophages, mouse macrophage RAW264.7 cells, and differentiated human monocytes (dTHP-1) in vitro. These effects were partially carried out via downregulating Nuclear factor kappa-B (NF-κB), Mitogen-activated protein kinases (MAPKs) (p38 mitogen-activated protein kinase and extracellular signal-regulated kinase (ERK), but not c-Jun N-terminal kinase (JNK), and activating the AMP-activated protein kinase (AMPK) signaling pathway also seems to be important. Consistently, GA was also shown to inhibit the LPS-stimulated release of TNF-α and IL-6 in mice. Taken together, these findings suggest that GA can serve as an effective inflammatory inhibitor in vitro and in vivo.

Near-infrared conjugated polymers for photoacoustic imaging-guided photothermal/chemo combination therapy.

Conjugated polymers (CPs) with intensive near-infrared (NIR) absorption and high photothermal conversion efficiency (PCE) have emerged as a new generation of photothermal therapy (PTT) and photoacoustic imaging (PAI) agents for cancer therapy. PTT + chemotherapy has been identified as a powerful modality to offer synergistic effects in the destruction and monitoring of cancer tissues. In this study, diketopyrrolopyrrole-based polymers (DPP) were designed through a combination of donor-acceptor moieties. Then, doxorubicin (DOX) and DPP were co-encapsulated in tocopheryl polyethylene-glycol-succinate-cholesterol (TPGS-CHO) copolymers to build a combined theranostic system for tumor treatment. These combined NPs with high PCE (∼50%) and strong (NIR) absorption exhibit excellent real-time photoacoustic imaging detection and synergistic cancer inhibition.