Twenty years of ocean observations with China Argo.

The international Argo program, a global observational array of nearly 4 000 autonomous profiling floats initiated in the late 1990s, which measures the water temperature and salinity of the upper 2 000 m of the global ocean, has revolutionized oceanography. It has been recognized one of the most successful ocean observation systems in the world. Today, the proposed decade action "OneArgo" for building an integrated global, full-depth, and multidisciplinary ocean observing array for beyond 2020 has been endorsed. In the past two decades since 2002, with more than 500 Argo deployments and 80 operational floats currently, China has become an important partner of the Argo program. Two DACs have been established to process the data reported from all Chinese floats and deliver these data to the GDACs in real time, adhering to the unified quality control procedures proposed by the Argo Data Management Team. Several Argo products have been developed and released, allowing accurate estimations of global ocean warming, sea level change and the hydrological cycle, at interannual to decadal scales. In addition, Deep and BGC-Argo floats have been deployed, and time series observations from these floats have proven to be extremely useful, particularly in the analysis of synoptic-scale to decadal-scale dynamics. The future aim of China Argo is to build and maintain a regional Argo fleet comprising approximately 400 floats in the northwestern Pacific, South China Sea, and Indian Ocean, accounting for 9% of the global fleet, in addition to maintaining 300 Deep Argo floats in the global ocean (25% of the global Deep Argo fleet). A regional BGC-Argo array in the western Pacific also needs to be established and maintained.

Protocol to access unknown flanking DNA sequences using Wristwatch-PCR for genome-walking.

Here we describe a protocol for wristwatch PCR, an approach based on wristwatch-like structure formed between walking primers to obtain unknown flanks. We specify the criteria for designing wristwatch primers and gene-specific primers. We detail how to set wristwatch primer permutations to obtain personalized walking outcomes and improve walking efficiency. We describe experimental procedures for isolating a DNA of interest using three rounds of nested wristwatch PCR as well as the subsequent steps for DNA purification, cloning, and sequencing. For complete details on the use and execution of this protocol, please refer to Wang et al. (2022).1.

DAR-PCR: a new tool for efficient retrieval of unknown flanking genomic DNA.

Various PCR-based genome-walking methods have been developed to acquire unknown flanking DNA sequences. However, the specificity and efficacy levels, and the operational processes, of the available methods are unsatisfactory. This work proposes a novel walking approach, termed differential annealing-mediated racket PCR (DAR-PCR). The key to DAR-PCR is the use of primer-mediated intra-strand annealing (ISA). An ISA primer consists of a 5' root homologous to the known sequence and a heterologous 3' bud. In the single low-stringency cycle, the ISA primer anneals to a site on an unknown region and extends towards the sequence-specific primer (SSP) 1 site, thereby forming a target single-stranded DNA bound by the SSP1 complement and the ISA primer. In the subsequent more stringent cycles, its complementary strand is accumulated, owing to the differential annealing between the moderate-stringency ISA primer and the high-stringency SSP1. The accumulation of this strand provides an opportunity for ISA mediated by the ISA primer root. A loop-back extension subsequent to ISA occurs, creating a racket-like DNA with the known region positioned at both ends of the unknown sequence. This DNA is exponentially amplified during the secondary PCR driven by an SSP pair inner to SSP1. DAR-PCR was validated as an efficient walking method by determining unknown flanking sequences in Lactobacillus brevis and Oryza sativa.

Wristwatch PCR: A Versatile and Efficient Genome Walking Strategy.

Genome walking is a method used to retrieve unknown flanking DNA. Here, we reported wristwatch (WW) PCR, an efficient genome walking technique mediated by WW primers (WWPs). WWPs feature 5'- and 3'-overlap and a heterologous interval. Therefore, a wristwatch-like structure can be formed between WWPs under relatively low temperatures. Each WW-PCR set is composed of three nested (primary, secondary, and tertiary) PCRs individually performed by three WWPs. The WWP is arbitrarily annealed somewhere on the genome in the one low-stringency cycle of the primary PCR, or directionally to the previous WWP site in one reduced-stringency cycle of the secondary/tertiary PCR, producing a pool of single-stranded DNAs (ssDNAs). A target ssDNA incorporates a gene-specific primer (GSP) complementary at the 3'-end and the WWP at the 5'-end and thus can be exponentially amplified in the next high-stringency cycles. Nevertheless, a non-target ssDNA cannot be amplified as it lacks a perfect binding site for any primers. The practicability of the WW-PCR was validated by successfully accessing unknown regions flanking Lactobacillus brevis CD0817 glutamate decarboxylase gene and the hygromycin gene of rice. The WW-PCR is an attractive alternative to the existing genome walking techniques.

Deoxyribonucleic Acid 5-Hydroxymethylation in Cell-Free Deoxyribonucleic Acid, a Novel Cancer Biomarker in the Era of Precision Medicine.

Aberrant methylation has been regarded as a hallmark of cancer. 5-hydroxymethylcytosine (5hmC) is recently identified as the ten-eleven translocase (ten-eleven translocase)-mediated oxidized form of 5-methylcytosine, which plays a substantial role in DNA demethylation. Cell-free DNA has been introduced as a promising tool in the liquid biopsy of cancer. There are increasing evidence indicating that 5hmC in cell-free DNA play an active role during carcinogenesis. However, it remains unclear whether 5hmC could surpass classical markers in cancer detection, treatment, and prognosis. Here, we systematically reviewed the recent advances in the clinic and basic research of DNA 5-hydroxymethylation in cancer, especially in cell-free DNA. We further discuss the mechanisms underlying aberrant 5hmC patterns and carcinogenesis. Synergistically, 5-hydroxymethylation may act as a promising biomarker, unleashing great potential in early cancer detection, prognosis, and therapeutic strategies in precision oncology.

Spatial variations and long-term trends of potential evaporation in Canada.

Assessing the status and trend of potential evaporation (PE) is essential for investigating the climate change impact on the terrestrial water cycle. Despite recent advances, evaluating climate change impacts on PE using pan evaporation (Epan) data in cold regions is hindered by the unavailability of Epan measurements in cold seasons due to the freezing of water and sparse spatial distribution of sites. This study generated long-term PE datasets in Canada for 1979-2016 by integrating the dynamic evolutions of water-ice-snow processes into estimation in the Ecological Assimilation of Land and Climate Observations (EALCO) model. The datasets were compared with Epan before the spatial variations and trends were analyzed. Results show that EALCO PE and Epan measurements demonstrate similar seasonal variations and trends in warm seasons in most areas. Annual PE in Canada varied from 100 mm in the Northern Arctic to approximately 1000 mm in southern Canadian Prairies, southern Ontario, and East Coast, with about 600 mm for the entire landmass. Annual PE shows an increasing trend at a rate of 1.5-4 mm/year in the Northern Arctic, East, and West Canada. The increase is primarily associated with the elevated air temperature and downward longwave and shortwave radiation, with some regions contributed by augmented wind speed. The increase of annual PE is mainly attributed to the augmentation of PE in warm seasons.

Contributions of climate change to the terrestrial carbon stock of the arid region of China: A multi-dataset analysis.

Dryland ecosystems have been threatened in recent decades by rapid climate change. However, the effects of climate change and rising CO2 levels on the terrestrial carbon stock of the arid region of China remain unclear. In this study, we used three climate reanalysis datasets to drive an arid ecosystem model (AEM), which we used to assess uncertainties in spatial climate datasets. All simulations suggest that the arid region of China acted as a carbon sink (0.20-0.34 Pg C) from 1980 to 2014. However, we found large uncertainties in the spatial pattern of carbon stocks during this period, especially in northern Xinjiang and western Inner Mongolia. These uncertainties are related to changes in precipitation. To reduce the uncertainty of carbon stock assessment results in the arid region of China, efforts should be implemented to improve the reliability of climate data in northern Xinjiang and western Inner Mongolia. Specifically, China's policy makers should pay close attention to climate change and ecosystem health in southwestern Xinjiang. According to our study, this area experienced significant decreases in precipitation and increases in temperature from 1980 to 2014. The severe ecosystem degradation that occurred will very likely continue into the future. In addition, the Climate Forecast System Reanalysis (CFSR) dataset may overestimate ecosystem carbon sinks as this dataset overestimates the increase in precipitation in the arid region of China. Therefore, it is advisable to be cautious when using the CFSR dataset in ecological studies in northern Eurasian dryland areas.

Composition analysis and antioxidant activities of the Rhus typhina L. stem.

The present investigation reports the chemical composition of the Rhus typhina L. stem identified via mass spectrometry and NMR as gallic acid, 1-O-galloyl-ß-D-glucose, tryptophan, scopolin, methyl gallate, fustin, quercetin, rutin, and 1,2,3,4,6-penta-O-galloyl-ß-D-glucose. The antioxidant properties and the chemical composition contents of the R. typhina L. stem grown in different regions in China were determined. To determine the antioxidant activity, a total phenolic content analysis, 2, 2-diphenyl-1-picrylhydrazyl radical scavenging activity assay, ferric reducing antioxidant power assay, and ß-carotene linoleic acid model system were conducted. The results showed that the Rhus typhina L. stem possessed high antioxidant capacities due to its high phenolic content. The contents of the nine isolated compounds were determined by UPLC-ESI-MS/MS. The calibration curves of the nine isolated compounds were linear within the concentration range and the average recoveries were high. The result showed that 1-O-galloyl-ß-D-glucose, gallic acid, methyl gallate, and 1,2,3,4,6-penta-O-galloyl-ß-D-glucose could be the compounds mainly responsible for the antioxidant capacity of the R. typhina L. stem. This reveals that the R. typhina L. stem is a good source of antioxidants.

Composition analysis and antioxidant activities of the Rhus typhina L. stem / 药物分析学报

The present investigation reports the chemical composition of the Rhus typhina L. stem identified via mass spectrometry and NMR as gallic acid, 1-O-galloyl-β-D-glucose, tryptophan, scopolin, methyl gallate, fustin, quercetin, rutin, and 1,2,3,4,6-penta-O-galloyl-β-D-glucose. The antioxidant properties and the chemical composition contents of the R. typhina L. stem grown in different regions in China were de-termined. To determine the antioxidant activity, a total phenolic content analysis, 2, 2-diphenyl-1-pi-crylhydrazyl radical scavenging activity assay, ferric reducing antioxidant power assay, andβ-carotene linoleic acid model system were conducted. The results showed that the Rhus typhina L. stem possessed high antioxidant capacities due to its high phenolic content. The contents of the nine isolated compounds were determined by UPLC-ESI-MS/MS. The calibration curves of the nine isolated compounds were linear within the concentration range and the average recoveries were high. The result showed that 1-O-galloyl-β-D-glucose, gallic acid, methyl gallate, and 1,2,3,4,6-penta-O-galloyl-β-D-glucose could be the compounds mainly responsible for the antioxidant capacity of the R. typhina L. stem. This reveals that the R. typhina L. stem is a good source of antioxidants.

Metabolic profiling of Gegenqinlian decoction in rat plasma, urine, bile and feces after oral administration by ultra high performance liquid chromatography coupled with Fourier transform ion cyclotron resonance mass spectrometry.

Gegenqinlian decoction (GQLD) as a traditional Chinese medical (TCM) prescription is made from four Chinese herbs and has been used for centuries to treat pyrexia and diarrhea. In this work, an ultra-high performance liquid chromatography coupled with Fourier transform ion cyclotron resonance mass spectrometry (UHPLC-FT-ICR-MS) method was established to profile the metabolic fate of GQLD in rat plasma, urine, bile and feces. The analysis was performed on a Waters Acquity UPLC HSS T3 column (2.1 mm × 100 mm, 1.8 µm) at 35 °C within 25 min. A total of 174 compounds mainly including flavonoids, alkaloids and triterpenoids in rat plasma, urine, bile and feces after oral administration of GQLD were identified or tentatively characterized by comparison with retention times, accurate mass within 5 ppm error and their characteristic MS fragmentation ions. Among compounds in rats, 107 compounds are prototypes and 67 compounds are metabolites. Results demonstrated that metabolic pathways of GQLD in rats included methylation, demethylation, hydrogenation, hydrolysis, hydroxylation, methoxylation, sulfate conjugation and glucuronide conjugation. A clear understanding of the absorption and metabolism of GQLD is very important in its rational clinical use and pharmacological research. These findings enhance our understanding of the metabolism and effective forms of GQLD.

A plasma metabonomic analysis on potential biomarker in pyrexia induced by three methods using ultra high performance liquid chromatography coupled with Fourier transform ion cyclotron resonance mass spectrometry.

Pyrexia usually is a systemic pathological process that can lead to metabolic disorders. Metabonomics as a powerful tool not only can reveal the pathological mechanisms, but also can give insight into the progression of pyrexia from another angle. Thus, an ultra high performance liquid chromatography combined with Fourier transform ion cyclotron resonance mass spectrometry (UHPLC-FT-ICR-MS) metabonomic approach was employed for the first time to investigate the plasma biochemical characteristics of pyrexia induced by three methods and to reveal subtle metabolic changes under the condition of pyrexia so as to explore its mechanism. The acquired metabolic data of the models were subjected to principal component analysis (PCA) for allowing the clear separation of the pyrexia rats from the control rats. Variable importance for project values (VIP) and Student's t-test were used to screen the significant metabolic changes caused by pyrexia. Fifty-two endogenous metabolites were identified and putatively identified as potential biomarkers primarily associated with phospholipid metabolism, sphingolipid metabolism, fatty acid oxidation metabolism, fatty acid amides metabolism and amino acid metabolism, and related to bile acid biosynthesis and glycerolipid catabolism. LysoPC (14:0), LysoPC (18:3), LysoPC (20:4), LysoPC (16:0), phytosphingosine, Cer (d18:0/12:0), N-[(4E,8E)-1,3-dihydroxyoctadeca-4,8-dien-2-yl]hexadecanamide, oleamide, fatty acid amide C22:1, tryptophan, acetylcarnitine, palmitoylcarnitine and stearoylcarnitine were considered as common potential biomarkers of pyrexia rats induced by three methods: Our results revealed that the UHPLC-FT-ICR-MS-based metabolomic method is helpful for finding new potential metabolic markers for pyrexia detection and offers a good perspective in pyrexia research.

Remote sensing of ecosystem health: opportunities, challenges, and future perspectives.

Maintaining a healthy ecosystem is essential for maximizing sustainable ecological services of the best quality to human beings. Ecological and conservation research has provided a strong scientific background on identifying ecological health indicators and correspondingly making effective conservation plans. At the same time, ecologists have asserted a strong need for spatially explicit and temporally effective ecosystem health assessments based on remote sensing data. Currently, remote sensing of ecosystem health is only based on one ecosystem attribute: vigor, organization, or resilience. However, an effective ecosystem health assessment should be a comprehensive and dynamic measurement of the three attributes. This paper reviews opportunities of remote sensing, including optical, radar, and LiDAR, for directly estimating indicators of the three ecosystem attributes, discusses the main challenges to develop a remote sensing-based spatially-explicit comprehensive ecosystem health system, and provides some future perspectives. The main challenges to develop a remote sensing-based spatially-explicit comprehensive ecosystem health system are: (1) scale issue; (2) transportability issue; (3) data availability; and (4) uncertainties in health indicators estimated from remote sensing data. However, the Radarsat-2 constellation, upcoming new optical sensors on Worldview-3 and Sentinel-2 satellites, and improved technologies for the acquisition and processing of hyperspectral, multi-angle optical, radar, and LiDAR data and multi-sensoral data fusion may partly address the current challenges.

Comparison of laboratory and field remote sensing methods to measure forage quality.

Recent research in range ecology has emphasized the importance of forage quality as a key indicator of rangeland condition. However, we lack tools to evaluate forage quality at scales appropriate for management. Using canopy reflectance data to measure forage quality has been conducted at both laboratory and field levels separately, but little work has been conducted to evaluate these methods simultaneously. The objective of this study is to find a reliable way of assessing grassland quality through measuring forage chemistry with reflectance. We studied a mixed grass ecosystem in Grasslands National Park of Canada and surrounding pastures, located in southern Saskatchewan. Spectral reflectance was collected at both in-situ field level and in the laboratory. Vegetation samples were collected at each site, sorted into the green grass portion, and then sent to a chemical company for measuring forage quality variables, including protein, lignin, ash, moisture at 135 °C, Neutral Detergent Fiber (NDF), Acid Detergent Fiber (ADF), Total Digestible, Digestible Energy, Net Energy for Lactation, Net Energy for Maintenance, and Net Energy for Gain. Reflectance data were processed with the first derivative transformation and continuum removal method. Correlation analysis was conducted on spectral and forage quality variables. A regression model was further built to investigate the possibility of using canopy spectral measurements to predict the grassland quality. Results indicated that field level prediction of protein of mixed grass species was possible (r² = 0.63). However, the relationship between canopy reflectance and the other forage quality variables was not strong.

[Impact on the potential epidemic of dengue fever under warming winter in Hainan province].

OBJECTIVE: Impact of climate warming in winter on the potential epidemics of dengue fever in Hainan was assessed. METHODS: Based on historic data of mean monthly temperature in January from 8 weather observation stations, tendency and amplitude of variation were analyzed. Using 21 degrees C as lowest limit of temperature suitable for dengue fever transmission, impact caused by climate warming on dengue fever epidemic was estimated by means of geography information system (GIS), insect vector and epidemiological features. RESULTS: Temperature in winter in Hainan province had shown an obvious increase. The maximum amplitude of increase appeared in Dongfang which was 1.4 degrees C and the minimum 0.5 degrees C in Shanhudao, but the increase amplitude in the other stations was varied from 0.7 to 1.3 degrees C. By the year of 2050, 21 degrees C contour will have moved 190 km or so northward, nearly spanned 6/7 of distance from south to north in Hainan province and under the condition of daily fraction surviving of Aedes aegypti as P = 0.89, Qionghai city which stands north in Hainan province will probably have become epidemic area of dengue fever all year round. CONCLUSION: Climate warming in winter will probably make half or more of the areas in Hainan province with temperature that permitting transmission of dengue fever by 2050. Monitoring and prevention of dengue fever in winter should be emphasized.