| 3031. |
- Li, Shu-Chen, et al.
(författare)
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Ebbinghaus Revisited : Influences of the BDNF Val66Met Polymorphism on Backward Serial Recall Are Modulated by Human Aging.
- 2010
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Ingår i: Journal of cognitive neuroscience. - Cambridge, Mass. : MIT Press - Journals. - 0898-929X .- 1530-8898. ; 22:10, s. 2164-2173
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Tidskriftsartikel (refereegranskat)abstract
- Abstract The brain-derived neurotrophic factor (BDNF) plays an important role in activity-dependent synaptic plasticity, which underlies learning and memory. In a sample of 948 younger and older adults, we investigated whether a common Val66Met missense polymorphism (rs6265) in the BDNF gene affects the serial position curve-a fundamental phenomenon of associative memory identified by Hermann Ebbinghaus more than a century ago. We found a BDNF polymorphism effect for backward recall in older adults only, with Met-allele carriers (i.e., individuals with reduced BDNF signaling) recalling fewer items than Val homozygotes. This effect was specific to the primacy and middle portions of the serial position curve, where intralist interference and associative demands are especially high. The poorer performance of older Met-allele carriers reflected transposition errors, whereas no genetic effect was found for omissions. These findings indicate that effects of the BDNF polymorphism on episodic memory are most likely to be observed when the associative and executive demands are high. Furthermore, the findings are in line with the hypothesis that the magnitude of genetic effects on cognition is greater when brain resources are reduced, as is the case in old age.
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| 3032. |
- Li, S. J., et al.
(författare)
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The 1p36 Tumor Suppressor KIF 1B beta Is Required for Calcineurin Activation, Controlling Mitochondrial Fission and Apoptosis
- 2016
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Ingår i: Developmental Cell. - : Elsevier BV. - 1534-5807 .- 1878-1551. ; 36:2, s. 164-178
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Tidskriftsartikel (refereegranskat)abstract
- KIF1B beta is a candidate 1p36 tumor suppressor that regulates apoptosis in the developing sympathetic nervous system. We found that KIF1B beta activates the Ca2+-dependent phosphatase calcineurin (CN) by stabilizing the CN-calmodulin complex, relieving enzymatic autoinhibition and enabling CN substrate recognition. CN is the key mediator of cellular responses to Ca2+ signals and its deregulation is implicated in cancer, cardiac, neurodegenerative, and immune disease. We show that KIF1B beta affects mitochondria! dynamics through CN-dependent dephosphorylation of Dynamin-related protein 1 (DRP1), causing mitochondria! fission and apoptosis. Furthermore, KIF1B beta actuates recognition of all known CN substrates, implying a general mechanism for KIF1B beta in Ca2+ signaling and how Ca2+-dependent signaling is executed by CN. Pathogenic KIF1B beta mutations previously identified in neuroblastomas and pheochromocytomas all fail to activate CN or stimulate DRP1 dephosphorylation. Importantly, KIF1B beta and DRP1 are silenced in 1p36 hemizygous-deleted neuroblastomas, indicating that deregulation of calcineurin and mitochondria! dynamics contributes to high-risk and poor-prognosis neuroblastoma.
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| 3033. |
- Li, W., et al.
(författare)
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Methane production through anaerobic digestion : Participation and digestion characteristics of cellulose, hemicellulose and lignin
- 2018
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Ingår i: Applied Energy. - : Elsevier Ltd. - 0306-2619 .- 1872-9118. ; 226, s. 1219-1228
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Tidskriftsartikel (refereegranskat)abstract
- Lignocellulosic biomass is the most abundant natural resource with high biomethane potential. However, complex structure of lignocellulosic biomass has hampered the efficient utilization of this bioresource. Previous studies have investigated the overall anaerobic digestion performance of lignocellulosic biomass, but the individual participation of each lignocellulosic component during anaerobic digestion remained unclear. Thus, this study investigated the methane production characteristics of cellulose, hemicellulose, lignin and their mixtures along with the microbial communities involved in anaerobic digestion. The results showed that the biomethane potential of cellulose was higher than that of hemicellulose; however, hemicellulose was hydrolysed more quickly than cellulose, while lignin was very difficult to be digested. The higher concentrations of acetic, n-butyric and n-valeric acids hydrolysed from the hemicellulose resulted in a lower pH and more severe inhibition on methane production than that of cellulose, and the methanogenesis gradually recovered after pH adjustment. The co-digestion of cellulose and hemicellulose increased the methane yield and biodegradability compared to mono-digestions. The addition of lignin to cellulose brought more significant decrease in the methane yield of cellulose than that of hemicellulose. Substrate-related bacteria such as Clostridium sensu stricto, Lutaonella, Cloacibacillus and Christensenella showed higher relative abundance in cellulose digestate, and sugar-fermenting bacteria such as Saccharofermentans, Petrimonas and Levilinea were more rich in the digestate of hemicellulose. Moreover, methanogenic Methanospirillum and Methanothrix likely contributed to the methane production of cellulose, while aciduric methanogens from Methanobrevibacter, Methanomassiliicoccus, Methanobacterium and Methanoculleus contributed to that of hemicellulose. This study provides a deeper understanding of the mechanism in the bioconversion of lignocellulosic biomass during anaerobic digestion.
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| 3034. |
- Li, X., et al.
(författare)
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Depot-specific messenger RNA expression of 11 beta-hydroxysteroid dehydrogenase type 1 and leptin in adipose tissue of children and adults
- 2007
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Ingår i: International Journal of Obesity. - London : Macmillan. - 0307-0565 .- 1476-5497. ; 31:5, s. 820-828
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To compare expression of messenger RNA (mRNA) coding for the cortisol regenerating enzyme 11-hydroxysteroid dehydrogenase type 1 (11-HSD1), and the adipocytokines leptin and resistin in paired biopsies of subcutaneous adipose tissue (SC) and omental adipose tissue (OM) from children. Design: Paired biopsies (SC and OM) were obtained from 54 children (age 0.17–16 years, body mass index (BMI) 12.5–28.3 kg/m2, BMI standard deviation score (SDS) -2.5–4.5) and 16 adults (age 27–79 years, BMI 19–46 kg/m2) undergoing open abdominal surgery. mRNA levels of 11-HSD1, leptin and resistin were measured using quantitative real-time polymerase chain reaction (PCR). Results: 11-HSD1 mRNA level was higher in OM than in SC (P<0.05), whereas leptin mRNA was higher in SC than in OM (P<0.001). There was no difference in the resistin mRNA level between SC and OM. These results were consistent in children and adults. In children, 11-HSD1 mRNA in SC was positively associated with BMI SDS (P<0.05), whereas in OM it was positively associated with age (P<0.05). The association between 11-HSD1 expression and age remained significant after adjustment for BMI SDS and gender. Leptin mRNA was positively associated with BMI SDS (SC:P<0.001, OM: P<0.001) but not with age in children. In multiple regression analyses, including anthropometric variables and age, BMI SDS was independently associated with mRNA levels of 11-HSD1 (P<0.05) and leptin (P<0.001) in SC. When normal weight and overweight children were analyzed separately, 11-HSD1 mRNA levels were positively associated with leptin in OM in the overweight group (P<0.05). Conclusion: There are depot-specific differences in mRNA levels of 11-HSD1 and leptin in children and adults. The positive association of 11-HSD1 mRNA in OM with age may reflect a causal role in visceral fat accumulation during growth. Increasing 11-HSD1 and leptin mRNA in SC with increasing BMI SDS could suggest that the risk of metabolic consequences of obesity may be established early in life.
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| 3035. |
- Li, X, et al.
(författare)
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Expression of cellular inhibitor of apoptosis protein-2 in human subcutaneous and omental adipose tissue
- 2004
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Ingår i: International Journal of Obesity. - : Springer Science and Business Media LLC. - 0307-0565 .- 1476-5497. ; 28:3, s. 352-356
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: In the current study, we addressed the question if there is depot-specific expression of cellular inhibitor of apoptosis protein-2 (cIAP2) already in childhood and if the relative expression changes with age in parallel with increasing risk of developing visceral adiposity. SUBJECTS: Paired samples of human omental (OM) and subcutaneous (SC) adipose tissue were obtained from 23 patients (12 children and 11 adults). METHOD: mRNA level of cIAP2 was determined using reverse transcription-polymerase chain reaction (RT-PCR) and protein expression confirmed by Western blotting. Apoptosis indices were determined by terminal deoxynucleotidyl transferase-mediated dUTP-fluorescein nick-end labelling (TUNEL). RESULTS: cIAP2 mRNA was 1.51-fold higher in OM compared with SC adipose tissue (OM>SC in 20 of 23 subjects; P<0.001). Western blots were in agreement with mRNA expression (OM>SC in nine of 10 subjects, P<0.01). Subgroup analyses showed depot difference in both children (P<0.01) and adults (P<0.05). Contrary to the hypothesis, depot-specific difference in mRNA expression of cIAP2 was significantly higher in children compared with adults (P<0.05). We were unable to demonstrate any difference in the basal apoptosis rate between adipocytes from the two depots. There was no significant association between cIAP2 mRNA expression and BMI or sex. CONCLUSIONS: The results demonstrated for the first time that depot-specific difference in cIAP2 expression is consistent in children and adults. This suggests that the higher expression of cIAP2 in OM than in SC adipose tissue may be due to inherent properties of cells from the two depots. The more pronounced depot-specific difference in children than in adults may reflect a net gain in visceral adipose tissue during growth.
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| 3036. |
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| 3037. |
- Li, XB, et al.
(författare)
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Novel TCF21high pericyte subpopulation promotes colorectal cancer metastasis by remodelling perivascular matrix
- 2023
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Ingår i: Gut. - : BMJ. - 1468-3288 .- 0017-5749. ; 72:4, s. 710-721
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Tidskriftsartikel (refereegranskat)abstract
- Haematogenous dissemination is a prevalent route of colorectal cancer (CRC) metastasis. However, as the gatekeeper of vessels, the role of tumour pericytes (TPCs) in haematogenous metastasis remains largely unknown. Here, we aimed to investigate the heterogeneity of TPCs and their effects on CRC metastasis.DesignTPCs were isolated from patients with CRC with or without liver metastases and analysed by single-cell RNA sequencing (scRNA-seq). Clinical CRC specimens were collected to analyse the association between the molecular profiling of TPCs and CRC metastasis. RNA-sequencing, chromatin immunoprecipitation-sequencing and bisulfite-sequencing were performed to investigate the TCF21-regulated genes and mechanisms underlying integrin α5 onTCF21DNA hypermethylation. Pericyte-conditionalTcf21-knockout mice were constructed to investigate the effects of TCF21 in TPCs on CRC metastasis. Masson staining, atomic force microscopy, second-harmonic generation and two-photon fluorescence microscopy were employed to observe perivascular extracellular matrix (ECM) remodelling.ResultsThirteen TPC subpopulations were identified by scRNA-seq. A novel subset of TCF21highTPCs, termed ‘matrix–pericytes’, was associated with liver metastasis in patients with CRC. TCF21 in TPCs increased perivascular ECM stiffness, collagen rearrangement and basement membrane degradation, establishing a perivascular metastatic microenvironment to instigate colorectal cancer liver metastasis (CRCLM).Tcf21depletion in TPCs mitigated perivascular ECM remodelling and CRCLM, whereas the coinjection of TCF21highTPCs and CRC cells markedly promoted CRCLM. Mechanistically, loss of integrin α5 inhibited the FAK/PI3K/AKT/DNMT1 axis to impairTCF21DNA hypermethylation in TCF21highTPCs.ConclusionThis study uncovers a previously unidentified role of TPCs in haematogenous metastasis and provides a potential diagnostic marker and therapeutic target for CRC metastasis.
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| 3038. |
- Li, X. P., et al.
(författare)
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Contribution of vanishing mountain glaciers to global and regional terrestrial water storage changes
- 2023
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Ingår i: Frontiers in Earth Science. - : Frontiers Media SA. - 2296-6463. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Mountain is called the water towers of the world. Due to high sensitivity and vulnerability to climate change, more attention is paid to the change of water resources in mountain regions, where provide water for environmental and human demands downstream. Mountains glacier, as one of the most important components of terrestrial water storage (TWS), effectively regulates and stabilizes surface water resources. TWS appears to be trending below previous ranges in recent years, and glacier retreating is becoming the primary cause of TWS depletion in mountain regions. However, how much mountain glacier changes contribute to TWS changes around mountain regions is unknown. Here, we combine multi-source datasets to quantify the contribution rate over high-elevation mountain regions. On a global scale, the glacial melting is equivalent to about 49% of the total TWS decline during 2006-2015. TWS and glacier show decreasing trends in most of mountain regions and watersheds of the Third Pole and surroundings (TPs), but the contribution ranges from -23% to 728% in mountain regions and -21% to 99% in watersheds of TPs. There are larger contributions in regions with more glaciers, while smaller in less glaciercovered regions. Glacier together with other storage components play diverse roles across different mountain regions and watersheds, but factors with great influence are glacier, groundwater, soil water, reservoirs and lakes.
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| 3039. |
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| 3040. |
- Li, Ziyue, et al.
(författare)
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Integrating life cycle assessment and a farmer survey of management practices to study environmental impacts of peach production in Beijing, China
- 2022
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Ingår i: Environmental Science and Pollution Research. - : Springer Nature. - 0944-1344 .- 1614-7499.
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Tidskriftsartikel (refereegranskat)abstract
- While intensive peach production has expanded rapidly in recent years, few studies have explored the environmental impacts associated with specific regional systems or the optimal management strategies to minimize associated environmental risks. Here, data from a survey of 290 native farmers were used to conduct a life cycle assessment to quantify the acidification potential (AP), global warming potential (GWP), eutrophication potential (EP), and reactive nitrogen (Nr) losses in peach production in Pinggu District, Beijing. Total annual Nr losses, and GWP, AP, and EP values for peach production in Pinggu District were respectively 10.7 kg N t−1, 857 kg CO2-eq t−1, 12.9 kg SO2-eq t−1, and 4.1 kg PO4-eq t−1. The principal driving factors were fertilizer production, transportation, and application, which together accounted for 94%, 67%, 75%, and 94% of Nr losses, GWP, AP, and EP, respectively. In the high yield, high nitrogen-use efficiency (HH) group, relative values of Nr losses, GWP, AP, and EP were respectively 33%, 25%, 39%, and 32% lower than the overall averages for 290 orchards. Further analyses indicate that improved farming practices such as decreasing application rates of fertilizers, increasing proportion of base fertilization rate, and proper fertilization frequency in the HH group were the main reasons for these orchards’ better performance in peach yields and partial factor productivity of nitrogen fertilizer, and their reduced environmental impacts. These results highlight the need to optimize nutrient management in peach production in order simultaneously to realize both environmental sustainability and high productivity in the peach production system.
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