Cross-Platform Comparison of Highly Sensitive Immunoassays for Inflammatory Markers in a COVID-19 Cohort.

A variety of commercial platforms are available for the simultaneous detection of multiple cytokines and associated proteins, often employing Ab pairs to capture and detect target proteins. In this study, we comprehensively evaluated the performance of three distinct platforms: the fluorescent bead-based Luminex assay, the proximity extension-based Olink assay, and a novel proximity ligation assay platform known as Alamar NULISAseq. These assessments were conducted on human serum samples from the National Institutes of Health IMPACC study, with a focus on three essential performance metrics: detectability, correlation, and differential expression. Our results reveal several key findings. First, the Alamar platform demonstrated the highest overall detectability, followed by Olink and then Luminex. Second, the correlation of protein measurements between the Alamar and Olink platforms tended to be stronger than the correlation of either of these platforms with Luminex. Third, we observed that detectability differences across the platforms often translated to differences in differential expression findings, although high detectability did not guarantee the ability to identify meaningful biological differences. Our study provides valuable insights into the comparative performance of these assays, enhancing our understanding of their strengths and limitations when assessing complex biological samples, as exemplified by the sera from this COVID-19 cohort.

NULISA: a proteomic liquid biopsy platform with attomolar sensitivity and high multiplexing.

The blood proteome holds great promise for precision medicine but poses substantial challenges due to the low abundance of most plasma proteins and the vast dynamic range of the plasma proteome. Here we address these challenges with NUcleic acid Linked Immuno-Sandwich Assay (NULISA™), which improves the sensitivity of traditional proximity ligation assays by ~10,000-fold to attomolar level, by suppressing assay background via a dual capture and release mechanism built into oligonucleotide-conjugated antibodies. Highly multiplexed quantification of both low- and high-abundance proteins spanning a wide dynamic range is achieved by attenuating signals from abundant targets with unconjugated antibodies and next-generation sequencing of barcoded reporter DNA. A 200-plex NULISA containing 124 cytokines and chemokines and other proteins demonstrates superior sensitivity to a proximity extension assay in detecting biologically important low-abundance biomarkers in patients with autoimmune diseases and COVID-19. Fully automated NULISA makes broad and in-depth proteomic analysis easily accessible for research and diagnostic applications.

Cross-platform comparison of highly-sensitive immunoassays for inflammatory markers in a COVID-19 cohort 1.

A variety of commercial platforms are available for the simultaneous detection of multiple cytokines and associated proteins, often employing antibody pairs to capture and detect target proteins. In this study, we comprehensively evaluated the performance of three distinct platforms: the fluorescent bead-based Luminex assay, the proximity extension-based Olink assay, and a novel proximity ligation assay platform known as Alamar NULISAseq. These assessments were conducted on serum samples from the NIH IMPACC study, with a focus on three essential performance metrics: detectability, correlation, and differential expression. Our results reveal several key findings. Firstly, the Alamar platform demonstrated the highest overall detectability, followed by Olink and then Luminex. Secondly, the correlation of protein measurements between the Alamar and Olink platforms tended to be stronger than the correlation of either of these platforms with Luminex. Thirdly, we observed that detectability differences across the platforms often translated to differences in differential expression findings, although high detectability did not guarantee the ability to identify meaningful biological differences. Our study provides valuable insights into the comparative performance of these assays, enhancing our understanding of their strengths and limitations when assessing complex biological samples, as exemplified by the sera from this COVID-19 cohort.

Can natural environments enhance acute effects of rehabilitation exercise for older adults? A pilot randomized controlled trial.

The added value of natural environments in rehabilitation exercise is unclear. This study aimed to investigate whether there are more acute health benefits for older adults after a single rehabilitation exercise session performed in an outdoor natural environment compared with an indoor environment. Twenty-two nursing home residents were randomly assigned to the outdoor (n = 11, 79.5 ± 2.1 years) or indoor group (n = 11, 78.8 ± 5.2 years). Performance test outcomes were measured pre- and post-training session. The indoor group had a significantly higher blood pressure, greater increase in heart rate, higher perceived exercise intensity and physiological fatigue than the outdoor group. The combination of rehabilitation exercise with an outdoor natural environment may reduce exercise fatigue and improve cardiovascular health in older adults, with greater acute health benefits compared with an indoor environment. Rehabilitation exercise in the natural environments may be a highly valued environmental intervention for physiotherapy in older adults.

NULISA: a novel proteomic liquid biopsy platform with attomolar sensitivity and high multiplexing.

The blood proteome holds great promise for precision medicine but poses substantial challenges due to the low abundance of most plasma proteins and the vast dynamic range across the proteome. We report a novel proteomic technology - NUcleic acid Linked Immuno-Sandwich Assay (NULISA™) - that incorporates a dual capture and release mechanism to suppress the assay background and improves the sensitivity of the proximity ligation assay by over 10,000-fold to the attomolar level. It utilizes pairs of antibodies conjugated to DNA oligonucleotides that enable immunocomplex purification and generate reporter DNA containing target- and sample-specific barcodes for a next-generation sequencing-based, highly multiplexed readout. A 200-plex NULISA targeting 124 cytokines and chemokines and 80 other immune response-related proteins demonstrated superior sensitivity for detecting low-abundance proteins and high concordance with other immunoassays. The ultrahigh sensitivity allowed the detection of previously difficult-to-detect, but biologically important, low-abundance biomarkers in patients with autoimmune diseases and COVID-19. Fully automated NULISA addresses longstanding challenges in proteomic analysis of liquid biopsies and makes broad and in-depth proteomic analysis accessible to the general research community and future diagnostic applications.

Novel lncRNA-prader willi/angelman region RNA, SNRPN neighbour (PWARSN) aggravates tubular epithelial cell pyroptosis by regulating TXNIP via dual way in diabetic kidney disease.

OBJECTIVES: Elevated thioredoxin-interacting protein (TXNIP)-induced pyroptosis contributes to the pathology of diabetic kidney disease (DKD). However, the molecular mechanisms in dysregulated TXNIP in DKD remain largely unclear. MATERIALS AND METHODS: Transcriptomic analysis identified a novel long noncoding RNA-Prader Willi/Angelman region RNA, SNRPN neighbour (PWARSN)-which was highly expressed in a proximal tubular epithelial cell (PTEC) under high glucose conditions. We focused on revealing the functions of PWARSN in regulating TXNIP-mediated pyroptosis in PTECs by targeting PWARSN expression via lentivirus-mediated overexpression and CRISPR-Cas9-based knockout in vitro and overexpressing PWARSN in the renal cortex by AAV-9 targeted injection in vivo. A number of molecular techniques disclosed the mechanisms of PWARSN in regulating TXNIP induced-pyroptosis in DKD. RESULTS: TXNIP-NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome and PTEC pyroptosis were activated in the renal tubules of patients with DKD and in diabetic mice. Then we explored that PWARSN enhanced TXNIP-driven PTECs pyroptosis in vitro and in vivo. Mechanistically, cytoplasmic PWARSN sponged miR-372-3p to promote TXNIP expression. Moreover, nuclear PWARSN interacted and facilitated RNA binding motif protein X-linked (RBMX) degradation through ubiquitination, resulting in the initiation of TXNIP transcription by reducing H3K9me3-enrichment at the TXNIP promoter. Further analysis indicated that PWARSN might be a potential biomarker for DKD. CONCLUSIONS: These findings illustrate distinct dual molecular mechanisms for PWARSN-modulated TXNIP and PTECs pyroptosis in DKD, presenting PWARSN as a promising therapeutic target for DKD.

[Investigation and analysis of imported medicinal materials at Chinese border ports].

Imported medicinal materials are an important part of Chinese medicinal resources. To be specific, about 10% of the around 600 commonly used Chinese medicinal materials are from abroad, and the introduction of foreign medicinal materials has promoted the development of Chinese medicine. Amid the advancement of reform and opening up and the "Belt and Road" Initiative, major headway has been made in the cross-border trade in China, bringing opportunities for the import of medicinal materials from border ports. However, for a long time, there is a lack of systematic investigation on the types of exotic medicinal materials at border ports. In the fourth national census of traditional Chinese medicine resources, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, together with several organizations, investigated the nearly 40 border ports, Chinese medicinal material markets, and border trade markets in 6 provinces/autonomous regions in China for the first time and recorded the types, sources, circulation, and the transaction characteristics of imported medicinal materials. Moreover, they invited experts to identify the origins of the collected 237 medicinal materials. In addition, the status quo and the problems of the medicinal materials were summarized. This study is expected to lay a basis for clarifying the market and origins of imported medicinal materials as well as the scientific research on and supervision of them.

The impact of IPACK combined with adductor canal block under ultrasound guidance on early motor function after total knee arthroplasty.

BACKGROUND: This study aimed to evaluate the impact of Infiltration between the Popliteal Artery and Capsule of the posterior Knee (IPACK) combined with an adductor canal block under the guidance of ultrasound on early motor function after Total Knee Arthroplasty (TKA). METHODS: A sample of 60 cases who were scheduled for elective unilateral TKA were divided into two groups using random number table method: a group with IPACK combined with an adductor canal block (I group, n = 30), and a group with femoral nerve block combined with superior popliteal sciatic nerve block (FS group, n = 30). Before anesthesia induction was completed, the patients in I group received an ultrasound-guided adductor canal block with 15 mL of 0.375% ropivacaine and an IPACK block with 25 mL of ropivacaine, and the patients in FS group received a femoral nerve block and a superior popliteal sciatic nerve block with 20 mL of 0.375% ropivacaine under ultrasound guidance. Post-operation, all the patients received patient-controlled intravenous analgesia combined with an oral celecoxib capsule to relieve pain and maintain a visual analogue scale score of ≤ 3. RESULTS: The quadriceps femoris muscle strength score was significantly higher in Ⅰ group than in FS group (p = 0.001), while the modified Bromage score were significantly lower and walking distance results were significantly higher in Ⅰ group than in FS group (both p = 0.000). CONCLUSION: Compared with femoral nerve block combined with superior popliteal sciatic nerve block, IPACK combined with adductor canal block had a mild impact on early motor functions after TKA.

Novel through-the-scope twin clip for the closure of GI wounds: the first experimental survival study in pigs (with videos).

BACKGROUND AND AIMS: We developed a through-the-scope twin clip (TTS-TC) for closing GI wounds. The objective of this study was to evaluate the efficacy and safety of the TTS-TC in GI wound closure. METHODS: GI nonperforating and perforating wounds (≥2.5 cm) were created in live pigs. TTS-TCs were used to convert the large wounds into small wounds. The remaining small wounds were closed using conventional through-the-scope clips (TTSCs). The follow-up period was 1 month. Location and size of the wound, time of wound closure, intraoperative and postoperative adverse events, and conditions of wound healing were investigated. RESULTS: Thirteen wounds were created in 5 live pigs, including 2 gastric nonperforating and 3 perforating wounds and 5 large intestinal nonperforating and 3 perforating wounds. The mean long and short diameters of the wounds were 4.1 (± .9) cm and 3.4 (± .7) cm, respectively. All wounds were successfully closed using the TTS-TCs combined with TTSCs. The total mean time for wound closure was 9.2 (± 5.3) minutes, and the mean time for using the TTS-TCs was 3.9 (± 4.7) minutes. During the 1-month follow-up period, no bleeding, perforation, or death occurred; all wounds healed with scar formation; and all TTS-TCs detached spontaneously. CONCLUSIONS: The TTS-TC was successfully used to close large-sized GI wounds. The TTS-TC is a promising tool for large-size wound closure under flexible endoscopy.

Spectrochemical determination of effects on rat liver of binary exposure to benzo[a]pyrene and 2,2',4,4'-tetrabromodiphenyl ether.

Benzo[a]pyrene (B[a]P) and polybrominated diphenyl ethers (PBDEs) are persistent environmental contaminants. The effects in organisms of exposures to binary mixtures of such contaminants remain obscure. Attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy is a label-free, non-destructive analytical technique allowing spectrochemical analysis of macromolecular components, and alterations thereof, within tissue samples. Herein, we employed ATR-FTIR spectroscopy to identify biomolecular changes in rat liver post-exposure to B[a]P and BDE-47 (2,2',4,4'-tetrabromodiphenyl ether) congener mixtures. Our results demonstrate that significant separation occurs between spectra of tissue samples derived from control versus exposure categories (accuracy = 87%; sensitivity = 95%; specificity = 79%). Additionally, there is significant spectral separation between exposed categories (accuracy = 91%; sensitivity = 98%; specificity = 90%). Segregation between control and all exposure categories were primarily associated with wavenumbers ranging from 1600 to 1700 cm-1 . B[a]P and BDE-47 alone, or in combination, induces liver damage in female rats. However, it is suggested that binary exposure apparently attenuates the toxic effects in rat liver of the individual contaminants. This is supported by morphological observations of liver tissue architecture on hematoxylin and eosin (H&E)-stained liver sections. Such observations highlight the difficulties in predicting the endpoint effects in target tissues of exposures to mixtures of environmental contaminants.

GmNFYA13 Improves Salt and Drought Tolerance in Transgenic Soybean Plants.

NF-YA transcription factors function in modulating tolerance to abiotic stresses that are serious threats to crop yields. In this study, GmNFYA13, an NF-YA gene in soybean, was strongly induced by salt, drought, ABA, and H2O2, and suppressed by tungstate, an ABA synthesis inhibitor. The GmNFYA13 transcripts were detected in different tissues in seedling and flowering stages, and the expression levels in roots were highest. GmNFYA13 is a nuclear localization protein with self-activating activity. Transgenic Arabidopsis plants overexpressing GmNFYA13 with higher transcript levels of stress-related genes showed ABA hypersensitivity and enhanced tolerance to salt and drought stresses compared with WT plants. Moreover, overexpression of GmNFYA13 resulted in higher salt and drought tolerance in OE soybean plants, while suppressing it produced the opposite results. In addition, GmNFYA13 could bind to the promoters of GmSALT3, GmMYB84, GmNCED3, and GmRbohB to regulate their expression abundance in vivo. The data in this study suggested that GmNFYA13 enhanced salt and drought tolerance in soybean plants.

Canan Outdoor Multisurface Terrain Enhance the Effects of Fall Prevention Exercise in Older Adults? A Randomized Controlled Trial.

Walking on complex surface conditions in outdoor environments is important for active aging. This study aimed at examining whether fall prevention exercise integrated with an outdoor multisurface terrain compared with indoor solid ground was more beneficial for older adults. Twenty-two older nursing home residents were randomly assigned to outdoor multisurface terrain (n = 11, 79.5 ± 2.1 years) or indoor solid ground (n = 11, 78.8 ± 5.2 years) groups. Training occurred five times per week (30 min) for 3 weeks. The following performance test outcomes were measured: 10 m walk test (10 mWT), multisurface terrain walk test (MTWT), 2 min walk test (2 MWT), timed up and go test (TUGT), single-leg standing test with eyes open (SLSTEO), single-leg standing test with eyes closed (SLSTEC), and closed cycles test (CCT). Compared with baseline, the outdoor multisurface terrain training significantly improved performance in all tests (p < 0.01). The improvements of the outdoor multisurface terrain group after intervention were significantly higher than those of the indoor solid group in the 10 mWT (p = 0.049), MTWT (p = 0.02), and 2 MWT (p = 0.000). Exercise combined with outdoor multisurface terrain training may be an efficacious approach and a feasible environmental intervention for fall prevention in older adults.

MicroRNA-18a-5p mitigates oxygen-glucose-deprivation/reoxygenation-induced injury through suppression of TLRs/NF-κB signaling by targeting TLR8 in PC12 cells.

This work aimed to assess the role of TLR8 in cerebral I/R injury and its in-depth pathogenesis. Bioinformatics analysis indicated that TLR8 was up-regulated in patients with ischemic stroke than that in healthy control, and miR-18a-5p was the upstream regulatory of TLR8. Then, the rat pheochromocytoma PC12 cells were exposed in oxygen-glucose-deprivation/reoxygenation (OGD/R) conditions to construct a model in vitro. The functional experiments indicated that OGD/R can decline the viability and elevate the apoptosis of PC12 cells, while up-regulation of miR-18a-5p can alleviate OGD/R-induced cell injury. Notably, overexpression of TLR8 reverses the miR-18a-5p-mediated protection on OGD/R-induced cells injury. Finally, we found that up-regulation of miR-18a-5p obviously declined the protein levels of TLR4 and TLR7 as well as the phosphorylation of NF-κB, while overexpression of TLR8 canceled the decrease caused by miR-18a-5p up-regulation. In summing, our results illustrated that miR-18a-5p/TLR8 axis can mitigate OGD/R-induced cells injury through TLRs and NF-κB pathway.

Mechanisms of resveratrol in the prevention and treatment of gastrointestinal cancer.

Gastrointestinal (GI) cancer is one of the leading causes of cancer-related deaths worldwide. According to the Global Cancer Statistics, colorectal cancer is the second leading cause of cancer-related mortality, closely followed by gastric cancer (GC). Environmental, dietary, and lifestyle factors including cigarette smoking, alcohol intake, and genetics are the most important risk factors for GI cancer. Furthermore, infections caused by Helicobacter pylori are a major cause of GC initiation. Despite improvements in conventional therapies, including surgery, chemotherapy, and radiotherapy, the length or quality of life of patients with advanced GI cancer is still poor because of delayed diagnosis, recurrence and side effect. Resveratrol (3, 4, 5-trihydroxy-trans-stilbene; Res), a natural polyphenolic compound, reportedly has various pharmacologic functions including anti-oxidant, anti-inflammatory, anti-cancer, and cardioprotective functions. Many studies have demonstrated that Res also exerts a chemopreventive effect on GI cancer. Research investigating the anti-cancer mechanism of Res for the prevention and treatment of GI cancer has implicated multiple pathways including oxidative stress, cell proliferation, and apoptosis. Therefore, this paper provides a review of the function and molecular mechanisms of Res in the prevention and treatment of GI cancer.

Metformin Decreases Insulin Resistance in Type 1 Diabetes Through Regulating p53 and RAP2A in vitro and in vivo.

PURPOSE: Patients with type 1 diabetes (T1D) are associated with a high risk of multiple complications, so the development of T1D treatment is urgently needed. This study was set out to explore the molecular mechanism of metformin in the treatment of T1D insulin resistance. PATIENTS AND METHODS: Subcutaneous adipose tissues were collected from 68 T1D patients and 51 healthy controls. Insulin resistance model rats and cells were constructed and treated with metformin respectively. Western blot was used to detect p53 and RAP2A protein levels, and qPCR was utilized to measure p53 and RAP2A mRNA levels. SiRNA and RAP2A siRNA vectors were constructed to observe their effects on insulin resistance model cells. RESULTS: In T1D, p53 was up-regulated, while RAP2A was down-regulated. Metformin could effectively improve insulin resistance and inflammatory response while down-regulating p53 and up-regulating RAP2A. P53 induced insulin resistance and inflammatory response by inhibiting RAP2A and promoted apoptosis. CONCLUSION: Metformin improves T1D insulin resistance and inflammatory response through p53/RAP2A pathway, and the regulation of p53/RAP2A pathway is conducive to improving the efficacy of metformin in the treatment of insulin resistance.

[Application and safety evaluation of plant growth regulators in traditional Chinese medicine].

Plant growth regulator is a kind of synthetic pesticide with similar physiological activity to plant hormones. It has been widely used in grain, vegetables, fruits, flowers and other crops, and become an important technical guarantee for high yield, stable yield, high quality and efficient production of crops. In recent years, plant growth regulator is widely used in Chinese herbal medicine production for regulating the growth and development and increasing production of traditional. However the crop is different from general Chinese medicinal materials, the use of plant growth regulator should not only consider the effect of Chinese herbal medicine production, and also pay special attention to the influence of Chinese traditional medicine efficacy and safety. This paper reviewed the application of plant growth regulator in the traditional Chinese medicine, the impact on the quality and safety of Chinese medicinal materials, as well as plant growth regulator of residue limits standards and testing technology, so as to the scientific use of plant growth regulator, to promote Chinese standardization planting, provide the scientific basis to protect the safety of herbal medicine. At present, the indiscriminate use and abuse of plant growth regulators such as Zhuanggenling and bulking element are common in the production of Chinese crude drugs, which has led to a significant decline in the quality of some Chinese crude drugs, and resulted in the dual residual harm to the Chinese crude drugs and the cultivation environment, causing serious safety risks to human health. In the future, it is necessary to strengthen the registration management, use norms and limit standards of plant growth regulators in traditional Chinese medicinal materials, and strengthen the supervision and regulations on the use of fertilizer instead of medicine to avoid pesticide registration and other disorders, so as to provide a basis for the quality and safety monitoring of traditional Chinese medicinal materials. Simultaneously, it is encouraged to reduction or non-application of plant growth regulators in the production of Chinese medicinal materials, especially for traditional Chinese medicine which contains a variety of active ingredients. Therefore, it is actively advocated to cultivate Chinese medicinal materials through organic or ecological method.

Simultaneous Visualization of RNA and Protein Expression in Tissue Using a Combined RNAscope™ In Situ Hybridization and Immunofluorescence Protocol.

Gene expression analysis is critical to precisely characterize complex tissues and provide insight into a disease condition. Techniques like PCR, sequencing, and northern blotting are highly sensitive and specific but are unable to provide information about spatial positioning of target genes. Visualization of gene expression with a spatial context can be critical in identifying complex milieus in heterogenous tissues like tumors. The RNAscope in situ hybridization (ISH) technology detects target RNA expression with high sensitivity and specificity at single-cell resolution. To understand the cellular cross talk between different cell populations, it is essential to simultaneously study gene and protein expression within a complex tissue. This chapter details combining the RNAscope ISH assay with immunofluorescence (IF) in one protocol to simultaneously visualize gene expression and protein expression in human tumor tissue and mouse brain tissue.

Overexpression of GmNFYA5 confers drought tolerance to transgenic Arabidopsis and soybean plants.

BACKGROUND: Crop productivity is challenged by abiotic stresses, among which drought stress is the most common. NF-Y genes, especially NF-YA genes, regulate tolerance to abiotic stress. RESULTS: Soybean NF-Y gene GmNFYA5 was identified to have the highest transcript level among all 21 NF-YA genes in soybean (Glycine max L.) under drought stress. Drought-induced transcript of GmNFYA5 was suppressed by the ABA synthesis inhibitor naproxen (NAP). GmNFYA5 transcript was detected in various tissues at vegetative and reproductive growth stages with higher levels in roots and leaves than in other tissues, which was consist with the GmNFYA5 promoter: GUS fusion assay. Overexpression of GmNFYA5 in transgenic Arabidopsis plants caused enhanced drought tolerance in seedlings by decreasing stomatal aperture and water loss from leaves. Overexpression and suppression of GmNFYA5 in soybean resulted in increased and decreased drought tolerance, respectively, relative to plants with an empty vector (EV). Transcript levels of ABA-dependent genes (ABI2, ABI3, NCED3, LEA3, RD29A, P5CS1, GmWRKY46, GmNCED2 and GmbZIP1) and ABA-independent genes (DREB1A, DREB2A, DREB2B, GmDREB1, GmDREB2 and GmDREB3) in transgenic plants overexpressing GmNFYA5 were higher than those of wild-type plants under drought stress; suppression of GmNFYA5 transcript produced opposite results. GmNFYA5 probably regulated the transcript abundance of GmDREB2 and GmbZIP1 by binding to the promoters in vivo. CONCLUSIONS: Our results suggested that overexpression of GmNFYA5 improved drought tolerance in soybean via both ABA-dependent and ABA-independent pathways.

[Effects of extraction methods on soil water isotope and plant water source segmentation.] / æå–æ–¹æ³•å¯¹åœŸå£¤æ°´åŒä½ç´ å’Œæ¤ç‰©æ°´æºåˆ†å‰²çš„å½±å“.

We used two types of soil with different physicochemical properties (loam and sand), oven-dried them, and then added the known isotopic composition mineral water that was reference water to compose the soil-water mixture with different soil water contents (loam: 0.15, 0.20, 0.30 g·g-1; sand: 0.10 g·g-1). After that, we set up different equilibrium time (loam: 3, 6, 12, 24, 48, 72, 96 h; sand: 96 h) to ensure that the dry soil particles were well mixed with the added water. The soil water was extracted by mechanical centrifugation and cryogenic vacuum extraction after equilibrium, and their isotope composition was analyzed. Results showed that the isotopic values of soil water extracted by mechanical centrifugation method had no significant difference in same water content with different equilibration times, but were more enriched compared with the reference water isotopic value. The maximum enrichment for hydrogen and oxygen isotope was 7.38‰ and 1.24‰, respectively. In contrast, cryogenic vacuum extraction method resulted in more depleted soil water isotopes than reference water, with the maximum depletion for hydrogen and oxygen isotope being 6.27‰ and 1.03‰, respectively. Moreover, the degree of depletion increased with the increases of equilibrium time (less than 24 h) at low water content, and became stable after 24 h. With the increases of soil water content, the isotopic composition of the extracted soil water was less affected by the two extraction methods. The water isotope value of loam that had high clay content, was more sensitive to the extraction method than the sandy soil that had low clay content. The difference of isotopic composition caused by extraction methods did not affect the plant water source segmentation.

Molecular dynamics simulations on RORγt: insights into its functional agonism and inverse agonism.

The retinoic acid receptor-related orphan receptor (ROR) γt receptor is a member of nuclear receptors, which is indispensable for the expression of pro-inflammatory cytokine IL-17. RORγt has been established as a drug target to design and discover novel treatments for multiple inflammatory and immunological diseases. It is important to elucidate the molecular mechanisms of how RORγt is activated by an agonist, and how the transcription function of RORγt is interrupted by an inverse agonist. In this study we performed molecular dynamics simulations on four different RORγt systems, i.e., the apo protein, protein bound with agonist, protein bound with inverse agonist in the orthosteric-binding pocket, and protein bound with inverse agonist in the allosteric-binding pocket. We found that the orthosteric-binding pocket in the apo-form RORγt was mostly open, confirming that apo-form RORγt was constitutively active and could be readily activated (ca. tens of nanoseconds scale). The tracked data from MD simulations supported that RORγt could be activated by an agonist binding at the orthosteric-binding pocket, because the bound agonist helped to enhance the triplet His479-Tyr502-Phe506 interactions and stabilized H12 structure. The stabilized H12 helped RORγt to form the protein-binding site, and therefore made the receptor ready to recruit a coactivator molecule. We also showed that transcription function of RORγt could be interrupted by the binding of inverse agonist at the orthosteric-binding pocket or at the allosteric-binding site. After the inverse agonist was bound, H12 either structurally collapsed, or reorientated to a different position, at which the presumed protein-binding site was not able to be formed.