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Abstract Lipid biomarkers in sediments in the Pearl River Estuary (PRE) have been studied in several previous studies, but little is known about their occurrence in the overlying water. Here, we determined the concentrations of lipids (n -alkanes, n -alkanols, sterols and fatty acids) in suspended particulate matter (SPM) in surface water and in sediments from the PRE. The data will improve our understanding of the sources, transport and sedimentation of lipids in estuarine environments. Our results showed that short-chain (C 14–20) n -alkyl lipids contributed more than long-chain (C 21–34) n -alkyl lipids to the total lipid concentrations in both SPM and sediments, suggesting aquatic plants and bacteria were the main contributors, whereas terrestrial organic matter (OM) were the minor contributors of n -alkyl lipids. It suggested that phytoplankton and bacteria contributing >65% to the n -alkyl lipids of SPM based on the three end-member mixing models. The concentrations of most lipids, except n -alkanes, decreased quickly in the low-salinity mixing zone and slowly decreased thereafter, with a transient slight increased when the salinity was 20–25, which would have been caused by variations of primary production in the aquatic system. In May, when rainfall was highest, lipids were characterized by a substantial contribution of terrestrial n -alkanes in the upstream SPM. Microbial activity and lipid degradation were found to occur in the water, and were most intense in the low–salinity mixing zone. Terrigenous lipids contributed more to the total lipid concentrations in sediments than in SPM, which demonstrated that terrigenous OM is relatively recalcitrant, and aquatic phytoplankton-derived OM is labile. Graphical abstract Unlabelled Image Highlights • N-alkyl lipids and sterols in SPM and sediments along salinity gradient were studied. • Aquatic lipids were dominant in SPM, but terrestrial lipids increased in sediments. • Substantial input of terrestrial n -alkanes occurred in May when rainfall was highest. [ABSTRACT FROM AUTHOR]

Long chain alkyl diols in sediment cores were studied in the Yuedong Upwelling (YDU) area in the coastal northern South China Sea to investigate whether sea surface temperature (SST) and upwelling intensity over the last few decades can be traced by the diol-derived indices, i.e., the LDI (long chain diol index) as a proxy for SST and the DI-1 and DI-2 (diol index 1 and 2) as proxies for upwelling intensity. The influence of riverine long chain alkyl diols (e.g., 1,13- and 1,15-diols), which may affect LDI-reconstructed SSTs, was largely ruled out based on the comparison between diol distributions in suspended particulate materials in the Pearl River estuary and the core sediments. LDI-derived SSTs in downcore sediments matched well with local annual mean SSTs. The records of DI-2 changed in parallel with the local wind stress and inversely with SST at times of upwelling, suggesting that DI-2 is an effective proxy for upwelling intensity of YDU. The DI-1 showed a generally inverse variation pattern with DI-2, implying a major influence by SST, and it is thus not an applicable upwelling indicator for YDU. A negative relationship of DI-1 and a positive relationship of DI-2 with LDI-derived SST were observed. This occurrence might be attributed to El Niño–Southern Oscillation (ENSO), because the SST and upwelling intensity were largely modulated by ENSO, showing a warm annual mean SST during the years of enhanced El Niño and intensified summer upwelling. [ABSTRACT FROM AUTHOR]

Extreme weather events are expected to occur more frequently in the future, which may influence water distribution and uptake patterns in rocky mountainous areas of North China. To examine how plants respond and adapt to the extreme environment, we investigated water sources of the broadleaved tree species Quercus variabilis under a precipitation gradient (A: no natural precipitation, B: half of natural precipitation, C: natural precipitation, and D: twice the natural precipitation) using the stable isotope approach in the Beijing mountainous area. The results indicated that Q. variabilis exhibited considerable plasticity in the depth of water uptake and showed a strong dependence on deeper soil layers under the precipitation gradient. Q. variabilis mainly absorbed water from the 0–20 cm (20.02–28.61%) and 60–80 cm (22.81–29.44%) soil layers, and also used groundwater (26.32–30.54%) under the low soil water conditions of the A treatment. In the B treatment, Q. variabilis absorbed water from the groundwater (29.60–33.53%) and 60–80 cm (26.05–29.44%) soil layers and a small amount of water from 0 to 20 cm (10.67–12.25%). In the C and D treatments, the soil water content was greater than that of the B treatment; Q. variabilis still predominantly absorbed water from the 60–80 cm (26.88% and 27.35%, respectively) soil layer and groundwater (33.52% and 46.17%, respectively), and took minimal water from the 0–20 cm and 20–40 cm soil layers. We found that Q. variabilis showed no obvious responses to precipitation under the precipitation gradient, and its dimorphic root system allowed it to uptake different water sources under drought and humid environmental conditions and thus maintain its transpiration. Therefore, we can infer that Q. variabilis is well adapted to extreme precipitation events and has a strong adaptability to both extreme drought and flood conditions. [ABSTRACT FROM AUTHOR]

A total of 90 samples of suspended particulate matter (SPM) collected in surface waters of the East China Sea (ECS) in summer and winter were studied for archaeal isoprenoid glycerol dialkyl glycerol tetraether lipids (iGDGTs) and the derived sea surface temperature (SST) proxy, i.e. TEX 86 H . Our data showed that in summer SPM TEX 86 H correlated well with in-situ measured SST, but in winter the relationship became much poorer. We found that the bottom water depth (BWD) of 70 m was a critical depth when studying the TEX 86 H -SST relationship in winter SPM. In locations with BWD < 70 m, concentrations of iGDGTs in SPM were > 5x higher in winter than in summer, but TEX 86 H showed a much weaker correlation with in-situ measured SST. This was speculated to be caused by lateral transport of SPM and resuspension of surface sediments in winter due to strong winds. Whereas in locations with BWD > 70 m, TEX 86 H correlated well with in-situ measured SST, suggesting a minor influence of SPM lateral transport and sediment resuspension. Moreover, although only core iGDGTs were analyzed, we found that both summer and winter TEX 86 H values correlated better with in-situ measured SST than with seasonal and annual mean SST, suggesting that SPM iGDGTs were dominantly produced around the sampling time rather than encompassing longer time input. The linear relationships of SPM TEX 86 H with in-situ measured SST were different between winter (BWD > 70 m) and summer, likely due to seasonal archaeal community change. Published sedimentary TEX 86 H data in the ECS were reexamined here, and a BWD of 70 m was also found to be a critical depth. At sites with BWD > 70 m, TEX 86 H in sediments correlated well with annual mean SST, whereas the correlation became poor at BWD < 70 m, suggesting that sedimentary GDGTs were also greatly influenced by resuspension and lateral transport, and hence complicating the application of the proxy to shallow locations in the ECS. [ABSTRACT FROM AUTHOR]

CD166 has been considered a relatively specific marker of stem cells and cancer stem cells, and the altered expression of CD166 has also been reported as a prognostic marker of several other types of cancer. However, the molecular functions of CD166 in these cancer cells are largely unknown. In this study, we found that CD166 significantly enhanced epidermal growth factor receptor (EGFR) phosphorylation and prolonged epidermal growth factor (EGF)/EGFR signalling activation. In addition, EGF stimulation in CD166-overexpressing oral squamous carcinoma cells led to enhanced colony formation, invasion capacity and cytoskeletal re-organization in vitro and elevated tumourigenesis in vivo. Taken together, the results of our study identify CD166 as an intriguing therapeutic target for patients suffering from oral squamous cell carcinoma (OSCC). [ABSTRACT FROM AUTHOR]