Identification of anthropogenic source of Pb and Cd within two tropical seagrass species in South China: Insight from Pb and Cd isotopes.

Seagrass beds are susceptible to deterioration and heavy metals represent a crucial impact factor. The accumulation of heavy metal in two tropical seagrass species were studied in South China in this study and multiple methods were used to identify the heavy metal sources. E. acoroides (Enhalus acoroides) and T. hemperichii (Thalassia hemperichii) belong to the genus of Enhalus and Thalassia in the Hydrocharitaceae family, respectively. Heavy metal concentrations in the two seagrasses followed the order of Cr > Zn > Cu > Ni > As > Pb > Co > Cd based on the whole plant, and their bioconcentration factors were 31.8 ± 29.3 (Cr), 5.7 ± 1.3 (Zn), 7.0 ± 3.8 (Cu), 3.0 ± 1.9 (Ni), 1.2 ± 0.3 (As), 1.7 ± 0.9 (Pb), 9.1 ± 11.1 (Co) and 2.8 ± 0.6 (Cd), indicating the intense enrichment in Co and Cr within the two seagrasses. The two seagrasses were prone to accumulate all the listed heavy metals (except for As in E. acoroides), especially Co (BCFs of 1124) and Cr (BCFs of 2689) in the aboveground parts, and the belowground parts of both seagrasses also accumulated most metals (BCFs of 27) excluding Co and Pb. The Pb isotopic ratios (mean 208Pb/204Pb, 207Pb/204Pb and 206Pb/204Pb values of 38.2054, 15.5000 and 18.3240, respectively) and Cd isotopic compositions (δ114/110Cd values ranging from -0.09‰ to 0.58‰) within seagrasses indicated the anthropogenic sources of Pb and Cd including coal combustion, traffic emissions and agricultural activities. This study described the absorption characteristics of E. acoroides and T. hemperichii to some heavy metals, and further demonstrated the successful utilization of Pb and Cd isotopes as discerning markers to trace anthropogenic origins of heavy metals (mainly Pb and Cd) in seagrasses. Pb and Cd isotopes can mutually verify and be helpful to understand more information in pollution sources and improve the reliability of conclusion deduced from concentrations or a single isotope.

Resequencing of global Lotus corniculatus accessions reveals population distribution and genetic loci, associated with cyanogenic glycosides accumulation and growth traits.

BACKGROUND: Lotus corniculatus is a widely distributed perennial legume whose great adaptability to different environments and resistance to barrenness make it an excellent forage and ecological restoration plant. However, its molecular genetics and genomic relationships among populations are yet to be uncovered. RESULT: Here we report on a genomic variation map from worldwide 272 L. corniculatus accessions by genome resequencing. Our analysis suggests that L. corniculatus accessions have high genetic diversity and could be further divided into three subgroups, with the genetic diversity centers were located in Transcaucasia. Several candidate genes and SNP site associated with CNglcs content and growth traits were identified by genome-wide associated study (GWAS). A non-synonymous in LjMTR was responsible for the decreased expression of CNglcs synthesis genes and LjZCD was verified to positively regulate CNglcs synthesis gene CYP79D3. The LjZCB and an SNP in LjZCA promoter were confirmed to be involved in plant growth. CONCLUSION: This study provided a large number of genomic resources and described genetic relationship and population structure among different accessions. Moreover, we attempt to provide insights into the molecular studies and breeding of CNglcs and growth traits in L. corniculatus.

B7H3 targeting gold nanocage pH-sensitive conjugates for precise and synergistic chemo-photothermal therapy against NSCLC.

BACKGROUND: The combination of drug delivery with immune checkpoint targeting has been extensively studied in cancer therapy. However, the clinical benefit for patients from this strategy is still limited. B7 homolog 3 protein (B7-H3), also known as CD276 (B7-H3/CD276), is a promising therapeutic target for anti-cancer treatment. It is widely overexpressed on the surface of malignant cells and tumor vasculature, and its overexpression is associated with poor prognosis. Herein, we report B7H3 targeting doxorubicin (Dox)-conjugated gold nanocages (B7H3/Dox@GNCs) with pH-responsive drug release as a selective, precise, and synergistic chemotherapy-photothermal therapy agent against non-small-cell lung cancer (NSCLC). RESULTS: In vitro, B7H3/Dox@GNCs exhibited a responsive release of Dox in the tumor acidic microenvironment. We also demonstrated enhanced intracellular uptake, induced cell cycle arrest, and increased apoptosis in B7H3 overexpressing NSCLC cells. In xenograft tumor models, B7H3/Dox@GNCs exhibited tumor tissue targeting and sustained drug release in response to the acidic environment. Wherein they synchronously destroyed B7H3 positive tumor cells, tumor-associated vasculature, and stromal fibroblasts. CONCLUSION: This study presents a dual-compartment targeted B7H3 multifunctional gold conjugate system that can precisely control Dox exposure in a spatio-temporal manner without evident toxicity and suggests a general strategy for synergistic therapy against NSCLC.

Novel cucurmosin-based immunotoxin targeting programmed cell death 1-ligand 1 with high potency against human tumor in vitro and in vivo.

Immunotoxins are Ab-cytotoxin chimeric molecules with mighty cytotoxicity. Programmed cell death 1-ligand 1 (PD-L1), is a transmembrane protein expressed mainly in inflammatory tumor tissues and plays a pivotal role in immune escape and tumor progression. Although PD-L1 immune checkpoint therapy has been successful in some cases, many patients have not benefited enough due to primary/secondary resistance. In order to optimize the therapeutic efficacy of anti-PD-L1 mAb, we used durvalumab as the payload and CUS245C , a type I ribosome-inactivating protein isolated from Cucurbita moschata, as the toxin moiety, to construct PD-L1-specific immunotoxin (named D-CUS245C ) through the engineered cysteine residue. In vitro, D-CUS245C selectively killed PD-L1+ tumor cells. In vivo studies also showed that D-CUS245C had obvious antitumor effect on PD-L1+ human xenograft tumors in nude mice. In conclusion, in the combination of the toxin with mAb, this study developed a new immunotoxin targeting PD-L1, emphasizing a novel and promising treatment strategy and providing a valuable way to optimize cancer immunotherapy.

Linc00210 drives Wnt/ß-catenin signaling activation and liver tumor progression through CTNNBIP1-dependent manner.

BACKGROUND: Liver tumor initiating cells (TICs) have self-renewal and differentiation properties, accounting for tumor initiation, metastasis and drug resistance. Long noncoding RNAs are involved in many physiological and pathological processes, including tumorigenesis. DNA copy number alterations (CNA) participate in tumor formation and progression, while the CNA of lncRNAs and their roles are largely unknown. METHODS: LncRNA CNA was determined by microarray analyses, realtime PCR and DNA FISH. Liver TICs were enriched by surface marker CD133 and oncosphere formation. TIC self-renewal was analyzed by oncosphere formation, tumor initiation and propagation. CRISPRi and ASO were used for lncRNA loss of function. RNA pulldown, western blot and double FISH were used to identify the interaction between lncRNA and CTNNBIP1. RESULTS: Using transcriptome microarray analysis, we identified a frequently amplified long noncoding RNA in liver cancer termed linc00210, which was highly expressed in liver cancer and liver TICs. Linc00210 copy number gain is associated with its high expression in liver cancer and liver TICs. Linc00210 promoted self-renewal and tumor initiating capacity of liver TICs through Wnt/ß-catenin signaling. Linc00210 interacted with CTNNBIP1 and blocked its inhibitory role in Wnt/ß-catenin activation. Linc00210 silencing cells showed enhanced interaction of ß-catenin and CTNNBIP1, and impaired interaction of ß-catenin and TCF/LEF components. We also confirmed linc00210 copy number gain using primary hepatocellular carcinoma (HCC) samples, and found the correlation between linc00210 CNA and Wnt/ß-catenin activation. Of interest, linc00210, CTNNBIP1 and Wnt/ß-catenin signaling targeting can efficiently inhibit tumor growth and progression, and liver TIC propagation. CONCLUSION: With copy-number gain in liver TICs, linc00210 is highly expressed along with liver tumorigenesis. Linc00210 drives the self-renewal and propagation of liver TICs through activating Wnt/ß-catenin signaling. Linc00210 interacts with CTNNBIP1 and blocks the combination between CTNNBIP1 and ß-catenin, driving the activation of Wnt/ß-catenin signaling. Linc00210-CTNNBIP1-Wnt/ß-catenin axis can be targeted for liver TIC elimination.

LncAPC drives Wnt/ß-catenin activation and liver TIC self-renewal through EZH2 mediated APC transcriptional inhibition.

Liver tumor initiating cells (TICs), a small subset cells in tumor bulk, are responsible for liver tumor initiation, metastasis, and relapse. However, the regulatory mechanism of liver TICs remains largely unknown. Here we found a long noncoding RNA lncAPC, locating near from APC locus, was highly expressed in liver cancer and liver TICs. LncAPC was required for liver TIC self-renewal. Silencing and overexpressing lncAPC showed impaired and enhanced sphere formation capacity of liver TICs, respectively. By recruiting EZH2 to APC promoter, LncAPC inhibits APC transcription and thus drives the activation of Wnt/ß-catenin signaling. Attenuate binding between EZH2 and APC promoter was observed upon lncAPC knockdown. What is more, lncAPC-EZH2-APC axis can be targeted to eliminate liver TICs. Altogether, LncAPC promotes liver TIC self-renewal through EZH2-dependent APC transcriptional inhibition.

Anticancer efficacy of a nitric oxide-modified derivative of bifendate against multidrug-resistant cancer cells.

The development of multidrug resistance (MDR) not only actively transports a wide range of cytotoxic drugs across drug transporters but is also a complex interaction between a number of important cellular signalling pathways. Nitric oxide donors appear to be a new class of anticancer therapeutics for satisfying all the above conditions. Previously, we reported furoxan-based nitric oxide-releasing compounds that exhibited selective antitumour activity in vitro and in vivo. Herein, we demonstrate that bifendate (DDB)-nitric oxide, a synthetic furoxan-based nitric oxide-releasing derivative of bifendate, effectively inhibits the both sensitive and MDR tumour cell viability at a comparatively low concentration. Interestingly, the potency of DDB-nitric oxide is the independent of inhibition of the functions and expressions of three major ABC transporters. The mechanism of DDB-nitric oxide appears to be in two modes of actions by inducing mitochondrial tyrosine nitration and apoptosis, as well as by down-regulating HIF-1α expression and protein kinase B (AKT), extracellular signal-regulated kinases (ERK), nuclear factor κB (NF-κB) activation in MDR cells. Moreover, the addition of a typical nitric oxide scavenger significantly attenuated all the effects of DDB-nitric oxide, indicating that the cytotoxicity of DDB-nitric oxide is as a result of higher levels of nitric oxide release in MDR cancer cells. Given that acquired MDR to nitric oxide donors is reportedly difficult to achieve and genetically unstable, compound like DDB-nitric oxide may be a new type of therapeutic agent for the treatment of MDR tumours.

Hydrodynamics and dissolved organic matter components shaped the fate of dissolved heavy metals in an intensely anthropogenically disturbed estuary.

Anthropogenic activities and natural erosion caused abundant influx of heavy metals (HMs) and organic matter (OM) into estuaries characterized by the dynamic environments governed by tidal action and river flow. Similarities and differences in the fate of HM and OM as well as the influences of OM on HMs remain incomplete in estuaries with seasonal human activity and hydrodynamic force. To address this gap, dissolved HMs (dHMs) and fluorescence dissolved OM (FDOM) were investigated in the Pearl River Estuary, a highly seasonally anthropogenic and dynamic estuary. It aimed to elucidate the effects of hydrodynamic conditions and DOM on the seasonal fate of dHMs via the multivariate statistical methods. Our findings indicated dHMs and FDOM exhibited consistently higher levels in the upper estuarine and coastal waters in both seasons, predominantly controlled by the terrestrial/anthropogenic discharge. In the wet season, dHMs and humic-like substances (HULIS) were positively correlated, showing that dHMs readily combined with HULIS. This association led to a synchronous decrease offshore along the axis of the estuary and the transport following the river plume in the surface affected by the salt wedge. Contrarily, dHMs were prone to complex with protein-like components impacted by the hydrodynamics during the dry season. Principal component analysis (PCA) results revealed the terrestrial/anthropogenic inputs and the fresh-seawater mixing process were the most crucial factors responsible for the fate of dHM in wet and dry seasons, respectively, with DOM identified as a secondary but significant influencing factor in both seasons. This study holds significance in providing valuable insights into the migration, transformation, the ultimate fate of dHMs in anthropogenically influenced estuaries, as well as the intricate dynamics governing coastal ecosystems.

Carrimycin ameliorates lipopolysaccharide and cecal ligation and puncture-induced sepsis in mice.

Carrimycin (CA), sanctioned by China's National Medical Products Administration (NMPA) in 2019 for treating acute bronchitis and sinusitis, has recently been observed to exhibit multifaceted biological activities, encompassing anti-inflammatory, antiviral, and anti-tumor properties. Despite these applications, its efficacy in sepsis treatment remains unexplored. This study introduces a novel function of CA, demonstrating its capacity to mitigate sepsis induced by lipopolysaccharide (LPS) and cecal ligation and puncture (CLP) in mice models. Our research employed in vitro assays, real-time quantitative polymerase chain reaction (RT-qPCR), and RNA-seq analysis to establish that CA significantly reduces the levels of pro-inflammatory cytokines, namely tumor necrosis factor-alpha (TNF-α), interleukin 1 beta (IL-1ß), and interleukin 6 (IL-6), in response to LPS stimulation. Additionally, Western blotting and immunofluorescence assays revealed that CA impedes Nuclear Factor Kappa B (NF-κB) activation in LPS-stimulated RAW264.7 cells. Complementing these findings, in vivo experiments demonstrated that CA effectively alleviates LPS- and CLP-triggered organ inflammation in C57BL/6 mice. Further insights were gained through 16S sequencing, highlighting CA's pivotal role in enhancing gut microbiota diversity and modulating metabolic pathways, particularly by augmenting the production of short-chain fatty acids in mice subjected to CLP. Notably, a comparative analysis revealed that CA's anti-inflammatory efficacy surpasses that of equivalent doses of aspirin (ASP) and TIENAM. Collectively, these findings suggest that CA exhibits significant therapeutic potential in sepsis treatment. This discovery provides a foundational theoretical basis for the clinical application of CA in sepsis management.

Math1, retinoic acid, and TNF-α synergistically promote the differentiation of mucous cells in mouse middle ear epithelial cells in vitro.

BACKGROUND: A key issue in otitis media (OM) is mucous cell metaplasia in the middle ear mucosa, a condition for hyperproduction of mucus in the middle ear mucosa and development of chronic OM. However, little is known about the driving force for the differentiation of mucous cells in OM. METHODS: Mouse middle ear epithelial cells (mMEECs) were used in this study to test whether Math1, a critical transcription factor for the development of mucous cells in the intestine, synergizes with inflammatory cytokines (tumor necrosis factor-α (TNF-α)) and other epithelial differentiation factors (retinoid acid (RA)) to induce the differentiation of mMEECs into mucus-like cells in vitro. Simultaneously, Math1 was transduced into the middle ear mucosa in order to observe whether it induces mucous cell hyperplasia in vivo. RESULTS: Math1 significantly increased the mucus cell numbers in the middle ear mucosa of mice. Math1, in the presence of TNF-α and epithelial differentiation factor RA, synergistically promoted the differentiation of mMEECs into mucus-like cells through upregulation of mucins and their chaperones: trefoil factors in vitro. RA treatment for 12 h activated Math1, although RA alone had very limited effects on mucus-like cell differentiation. CONCLUSION: Math1 plays a critical role in the pathogenesis of OM by induction of mucous cell differentiation in the presence of TNF-α and RA.

Bioluminescent imaging of pneumococcal otitis media in chinchillas.

OBJECTIVES: Bioluminescent imaging has emerged as a powerful tool for monitoring the pathological process of infections in animals. The purpose of this study was to harness this new tool for objective assessment of acute otitis media (AOM) in animals with and without antibiotic interventions. METHODS: Thirty-six healthy chinchillas, free of middle ear infections, were randomly divided into a control group and a group that received amoxicillin treatment. Bioluminescent Streptococcus pneumoniae (Xen 10) was injected into the epitympanic bullae of chinchillas (50 colony-forming units each) for induction of AOM. The infectious process of Xen 10 in the bullae of living animals with and without antibiotic interventions was monitored in real time with bioluminescence equipment. RESULTS: A dynamic change of bioluminescent signals in the bullae of chinchillas from days 1 to 14 was observed after Xen 10 injection. Amoxicillin treatment reduced the bioluminescent signals in the bullae of chinchillas compared with controls. The AOM persisted for 14 days, and middle ear effusion for 6 weeks, in the control animals, whereas AOM lasted for 2 days, and effusion for 6 to 12 days, in the antibiotic-treated animals. CONCLUSIONS: Bioluminescent imaging provides an innovative method for assessment of the bacterial loads in the middle ear of chinchillas in a real-time manner and is very useful for objective evaluation of the efficacy of therapeutic interventions.

Ultrasensitive detection of SARS-CoV-2 antigen using surface-enhanced Raman spectroscopy-based lateral flow immunosensor.

The fast spread and transmission of the coronavirus 2019 (COVID-19) has become one of serious global public health problems. Herein, a surface enhanced Raman spectroscopy-based lateral flow immunoassay (LFA) was developed for the detection of SARS-CoV-2 antigen. Using uniquely designed core-shell nanoparticle with embedded Raman probe molecules as the indicator to reveal the concentration of target protein, excellent quantitative performance with a limit of detection (LOD) of 0.03 ng/mL and detection range of 10-1000 ng/mL can be achieved within 15 min. Besides, the detection of spiked virus protein in human saliva was also performed with a portable Raman spectrometer, proposing the feasibility of the method in practical applications. This easy-to-use, rapid and accurate method would provide a point-of-care testing way as the ideal alternative for current detection requirement of virus-related biomarkers.

Saltwater intrusion regulates the distribution and partitioning of heavy metals in water in a dynamic estuary, South China.

The mixing processes of fresh-salt water in estuarine and coastal regions have a substantial impact on the characteristics of heavy metals. A study was conducted in the Pearl River Estuary (PRE), located in South China, to examine the distribution and partitioning of heavy metals and the factors that influence their presence. Results showed that the hydrodynamic force, caused by the landward intrusion of the salt wedge, was the major contributor to the aggregation of heavy metals in the northern and western PRE. Conversely, metals were diffused seaward at lower concentrations along the plume flow in surface water. The study found that some metals, including Fe, Mn, Zn and Pb, were significantly higher in surface water than in bottom water in eastern waters, but the reverse was true in the southern offshore area, where limited mixing hindered the vertical transfer of metals in the water column. The partitioning coefficients (KD) of metals varied, with Fe exhibiting the highest KD (1038 ± 1093 L/g), followed by Zn (579 ± 482 L/g) and Mn (216 ± 224). The highest KD values of metals in surface water were observed in the west coast, while the highest KD in bottom water was found in eastern areas. Furthermore, re-suspension of sediment and the mixing of seawater and freshwater offshore, caused by seawater intrusion, resulted in the partitioning of Cu, Ni and Zn towards particulate phases in offshore waters. This study provides valuable insights into the migration and transformation of heavy metals in dynamic estuaries influenced by the interaction of freshwater and saltwater and highlights the importance of continued research in this field.

Effects of herbivore on seagrass, epiphyte and sediment carbon sequestration in tropical seagrass bed.

Herbivores strongly affect the ecological structure and functioning in seagrass bed ecosystems, but may exhibit density-dependent effects on primary producers and carbon sequestration. This study examined the effects of herbivorous snail (Cerithidea rhizophorarum) density on snail intraspecific competition and diet, dominant seagrass (Thalassia hemprichii) and epiphyte growth metrics, and sediment organic carbon (SOC). The growth rates of the herbivorous snail under low density (421 ind m-2) and mid density (842 ind m-2) were almost two times of those at extremely high density (1684 ind m-2), indicating strong intraspecific competition at high density. Herbivorous snails markedly reduced the epiphyte biomass on seagrass leaves. Additionally, the seagrass contribution to herbivorous snail as food source under high density was about 1.5 times of that under low density, while the epiphyte contribution under low density was 3 times of that under high density. A moderate density of herbivorous snails enhanced leaf length, carbon, nitrogen, total phenol and flavonoid contents of seagrasses, as well as surface SOC content and activities of polyphenol oxidase and ß-glucosidase. However, high density of herbivorous snails decreased leaf glucose, fructose, detritus carbon, and total phenols contents of seagrasses, as well as surface SOC content and activities of polyphenol oxidase and ß-glucosidase. Therefore, the effects of herbivorous snail on seagrass, epiphyte and SOC were density-dependent, and moderate density of herbivorous snail could be beneficial for seagrasses to increase productivity. This provided theoretical guidance for enhancing carbon sink in seagrass bed and its better conservation.

A drug-delivery depot for epigenetic modulation and enhanced cancer immunotherapy.

DNA methyltransferase inhibitors (DNMTis) have found widespread application in the management of cancer. Zebularine (Zeb), functioning as a demethylating agent, has exhibited notable advantages and enhanced therapeutic efficacy in the realm of tumour immunotherapy. Nevertheless, due to its lack of targeted functionality, standalone Zeb therapy necessitates the administration of a substantially higher dosage. In this investigation, we have devised an innovative nanodrug formulation, comprising the DNA methyltransferase inhibitor Zeb and pH-responsive chitosan (CS), hereinafter referred to as CS-Zeb nanoparticles (NPs). Our findings have unveiled that CS-Zeb NPs manifest heightened drug release within an acidic milieu (pH 5.5) in comparison to a neutral environment (pH 7.4). Furthermore, in vivo studies have conclusively affirmed that, in contrast to equivalent quantities of Zeb in isolation, the nanocomplex significantly curtailed tumour burden and protracted the survival duration of the B16F10 tumour-bearing murine model. Additionally, CS-Zeb NPs elicited an augmentation of CD8+ T cells within the peripheral circulation of mice and tumour-infiltrating lymphocytes (TILs). Notably, the dosage of CS-Zeb NPs was reduced by a remarkable 70-fold when juxtaposed with Zeb administered in isolation. To summarise, our study underscores the potential of CS-Zeb NPs as an alternative chemotherapeutic agent for cancer treatment.

Id-1 and the p65 subunit of NF-κB promote migration of nasopharyngeal carcinoma cells and are correlated with poor prognosis.

Inhibitor of differentiation (Id)-1 and nuclear factor-kappa B (NF-κB) have been detected in many malignant tumors, and their presence has been correlated with the metastatic potential of these tumors. This study was undertaken to investigate the prognostic significance of the expression of Id-1 and the p65 subunit of NF-κB (NF-κB/p65) and the proteins' roles in the invasion process of nasopharyngeal carcinoma (NPC) cells. The messenger RNA (mRNA) and protein levels of Id-1 and NF-κB/p65 in normal nasopharyngeal epithelial cells and NPC cell lines were examined using reverse transcription-PCR and western blot analysis, whereas the mRNA and protein levels of Id-1 and NF-κB/p65 in clinical NPC specimens were determined by reverse transcription-PCR and immunohistochemistry. Short hairpin RNA (shRNA) was used to silence Id-1 and NF-κB/p65 to allow for the examination of matrix metalloproteinase (MMP)-9 expression and migratory capacity changes in CNE-2 cells. Multivariate Cox analysis revealed that elevated Id-1 expression was a significant independent predictor of the 5 year overall survival rate (hazards ratio = 16.720, P = 0.005). Furthermore, elevated expression of both Id-1 and NF-κB/p65 was associated with poor clinical survival (P = 0.049). Targeting Id-1 and NF-κB/p65 mRNA with shRNA in CNE-2 cells inhibited MMP-9 expression and decreased the migratory capacity of CNE-2 cells. In conclusion, Id-1 expression is a novel independent prognostic marker molecule that helps identify NPC patients with a poor prognosis. Additionally, combined analysis of Id-1 and NF-κB/p65 can be useful for identifying patients at risk for unfavorable clinical outcomes. Id-1 or/and NF-κB/p65 enhanced tumor cell migration, which is associated with the secretion of MMP-9.

Id2 regulates the proliferation of squamous cell carcinoma in vitro via the NF-κB/Cyclin D1 pathway.

Squamous cell carcinoma(SCC) is a significant cause of cancer morbidity and mortality worldwide, with an incidence of up to 166 cases per 100 000 population. It arises in the skin, upper aerodigestive tract, lung, and cervix and affects more than 200 000 Americans each year. We report here that a microarray experiment comparing 41 SCC and 13 normal tissue specimens showed that Id2, a gene that controls the cell cycle, was significantly up-regulated in SCC. Enforced expression of Id2 in vitro stimulated the proliferation of SCC cells and up-regulated the transcription of nuclear factor kappa B (NF-κB) and cyclin D1. Enhancement of the NF-κB activity with p65 significantly increased the cell proliferation and the transcription of cyclin D1, whereas inhibition of the NF-κB activity with I kappa B alpha mutant (IκBαM) and pyrroline dithiocarbamate (PDTC) abrogated cell proliferation and transcription of cyclin D1. Furthermore, a mutated NF-κB binding site in the cyclin D1 promoter fully abrogated the Id2-induced transcription of cyclin D1. Taken together, these data indicate that Id2 induces SCC tumor growth and proliferation through the NF-κB/cyclin D1 pathway.

Eutrophication reduced the release of dissolved organic carbon from tropical seagrass roots through exudation and decomposition.

Seagrass bed ecosystem is one of the most effective carbon capture and storage systems on earth. Seagrass roots are the key link of carbon flow between leaf-root-sediment, and the release of dissolved organic carbon (DOC) from seagrass roots through exudation and decomposition are vital sources to the sediment organic carbon (SOC) in the seagrass beds. Unfortunately, human-induced eutrophication may change the release process of DOC from seagrass roots, thereby affecting the sediment carbon storage capacity. However, little is known about the effect of nutrient enrichment on the release of DOC from seagrass roots, hindering the development of seagrass underground ecology. Therefore, we selected Thalassia hemprichii, the tropical dominant seagrass species, as the research object, and made a comparison of the release of DOC from roots through exudation and decomposition under different nitrate treatments. We found that under control, 10 µmol L-1, 20 µmol L-1 and 40 µmol L-1 nitrate treatments, soluble sugar of T. hemprichii roots were 71.37 ± 3.43 mg g-1, 67.03 ± 5.33 mg g-1, 49.14 ± 3.48 mg g-1, and 18.51 ± 2.09 mg g-1, respectively, while the corresponding root DOC exudation rates were 7.00 ± 0.97 mg g DW root-1 h-1, 5.11 ± 0.42 mg g DW root-1 h-1, 4.08 ± 0.23 mg g DW root-1 h-1, and 3.78 ± 0.74 mg g DW root-1 h-1, respectively. There was a significant positive correlation between root soluble sugar and DOC exudation rate. DOC concentration of sediment porewater and SOC content also decreased under nitrate enrichment (though not significantly), which were both significantly positively correlated with the rate of root exuded DOC. Meanwhile, nitrate enrichment also reduced the release rate of DOC from seagrass roots during initial decomposition, and the release flux of DOC from decomposition. Therefore, nutrient enrichment could decrease nonstructural carbohydrates of seagrass roots, reducing the rate of root exuded DOC, thereby lowered SOC, as well as the DOC release from seagrass root decomposition. In order to increase the release of DOC from seagrass roots and improve the carbon sequestration capacity of seagrass beds, effective measures should be taken to control the coastal nutrients input into seagrass beds.

Characteristics of nutrients and heavy metals and potential influence of their benthic fluxes in the Pearl River Estuary, South China.

Nutrient and heavy metal concentrations in porewater/overlying water and their benthic fluxes were investigated to study their accumulation and transport at the sediment-water interface and the influences of sediment in the Pearl River Estuary, China. Results revealed that distribution of nutrients and metals reflected the effects of terrestrial inputs and some physicochemical processes. Benthic fluxes also suggested that nutrients and heavy metals Pb, Zn and Cd diffused from sediment to overlying water, but not for As, Co, Cr, Fe, Mn and Ni. Exchange capacities showed that 106-108 mol nutrients and 105-107 g Pb, Zn and Cd released from sediment to overlying water annually, indicating their potential ecological threat. However, 105-109 g metals As, Co, Cr, Fe, Mn and Ni were deposited annually, which may reduce the pollution pressure caused by anthropogenic activities. This study will provide references for the potential influence of benthic fluxes on estuarine environment globally.