Molecular map of cGAS-STING pathway-related genes in bladder cancer: the perspective toward immune microenvironment and prognosis.

BACKGROUND: The cGAS-STING pathway emerges as a pivotal innate immune pathway with the potential to profoundly influence all facets of tumor initiation and progression. The prognostic significance and immunological role of cGAS-STING pathway-related genes (CRGs) in individuals diagnosed with bladder cancer (BLCA) have not yet been fully elucidated. METHODS: Performed unsupervised cluster analysis to identify distinct clusters. Utilizing LASSO and multivariate Cox regression analysis to construct a prognostic risk model. The IMvigor210, GSE13507 and GSE78220 cohorts were utilized to explore the potential value of risk score in immune therapy response and survival prediction. RESULTS: A risk model was developed utilizing four CRGs in order to forecast the overall survival (OS) of BLCA patients. The risk score to be a standalone risk factor, which was further corroborated by the external validation set obtained from the GEO database (GSE13507). We established an integrated nomogram that combined risk scoring and clinical information, exhibiting commendable clinical practicality in predicting the overall survival period of BLCA patients. It is noteworthy that risk score could differentiate tumor microenvironments among different risk groups and individuals who were more responsive to immunotherapy in IMvigor210 and GSE13507 cohorts. In vitro experiments, we noted an up-regulation of IRF3 and IKBKB upon the activation of the cGAS-STING pathway. Conversely, the activation of the cGAS-STING pathway resulted in a down-regulation of POLR3G and CTNNB1. CONCLUSIONS: CRG risk model shows promise as a potential stratification approach for bladder cancer patients.

Potential impact of cuproptosis-related genes on tumor immunity in esophageal carcinoma.

Cuproptosis involves a direct interaction with the tricarboxylic acid (TCA) lipid acylation components. This process intricately intersects with post-transcriptional lipid acylation (LA) and is linked to mitochondrial respiration and LA metabolism. Copper ions form direct bonds with acylated DLAT, promoting DLAT oligomerization, reducing Fe-S cluster proteins, and inducing a protein-triggered toxic stress response that culminates in cell demise. Simultaneously, the importance of immune contexture in cancer progression and treatment has significantly increased. We assessed the expression of cuproptosis-related genes (CRGs) across TCGA and validated our findings using the GEO data. Consensus clustering divided esophageal cancer (ESCA) patients into two clusters based on the expression of 7 CRGs. We evaluated the expression of immune checkpoint inhibitor (ICI) targets and calculated the elevated tumor mutational burden (TMB). Weighted gene co-expression network analysis (WGCNA) identified genes associated with the expression of CRGs and immunity. Cluster 1 exhibited increased immune infiltration, higher expression of ICI targets, higher TMB, and a higher incidence of deficiency in mismatch repair-microsatellite instability-high status. WGCNA analysis identified 14 genes associated with the expression of CRGs and immune scores. ROC analysis revealed specific hub genes with strong predictive capabilities. The expression levels of SLC6A3, MITD1, and PDHA1 varied across different pathological stages; CCS, LIPT2, PDHB, and PDHA1 showed variation in response to radiation therapy; MITD1 and PDHA1 exhibited differences related to the pathological M stages of ESCA. CRGs influence the immune contexture and can potentially transform cold tumors into hot tumors in ESCA patients.

A novel and robust pyroptosis-related prognostic signature predicts prognosis and response to immunotherapy in esophageal squamous cell carcinoma.

Esophageal squamous cell carcinoma (ESCC) is a highly malignant gastrointestinal tumor, has a poor prognosis and high mortality rate. Pyroptosis could regulate tumor cell proliferation, invasion, and metastasis, thereby affecting the prognosis of cancer patients. However, the role of pyroptosis-related genes (PRGs) in ESCC remains unclear. This study selected 33 PRGs, and finally identified 29 PRGs that were differentially expressed between ESCC and normal esophageal tissues. The genetic mutation variation landscape of PRG in ESCC was also summarised. Based on consensus clustering for the 33 PRGs, all ESCC patients could be divided into two subtypes. Functional enrichment analysis revealed that these 33 PRGs were mainly involved in cytokine production, interleukin-1 production, and the NOD-like receptor signalling pathway. We created a prognostic PRG signature based on least absolute shrinkage and selection operator regression and Cox regression analysis with good survival prediction ability in both GEO and TCGA cohorts. Combined with the clinical characteristics, signature-based risk score was found to be an independent factor for predicting the OS of ESCC patients. A nomogram with enhanced precision for forecasting ESCC was established based on various independent prognostic elements. Significant correlation was observed between prognostic PRGs and immune-cell infiltration, tumor mutation burden, microsatellite instability, immune checkpoint, and drug sensitivity. Finally, we validated the expression of four PRGs in ESCC cell lines and tissues samples. In conclusion, the PRGs exerted significant effects on tumor immunity and prognosis of ESCC.

LINC00114 stimulates growth and glycolysis of esophageal cancer cells by recruiting EZH2 to enhance H3K27me3 of DLC1.

OBJECTIVE: LINC00114 could promote the development of colorectal cancer, but its mechanism has been rarely discussed in esophageal cancer (EC). Herein, we explored the molecular mechanism of LINC00114 via mediating enhancer of zeste homolog 2/deleted in liver cancer 1 (EZH2/DLC1) axis in EC. METHODS: LINC00114, EZH2 and DLC1 expression in EC tissues and cells were tested. LINC00114, EZH2 and DLC1 expression were altered in EC cells through transfection with different constructs, and cell proliferation, migration, invasion, apoptosis and glycolysis were subsequently observed. The interaction between LINC00114 and EZH2 and that between EZH2 and DLC1 were explored. Tumor formation was also conducted to confirm the in vitro results. RESULTS: The expression levels of LINC00114 and EZH2 were elevated while those of DLC1 were reduced in EC. Inhibiting LINC00114 or reducing EZH2 blocked cell proliferation, migration, invasion and glycolysis and induce cell apoptosis in EC. LINC00114 promoted H3K27 trimethylation of DLC1 by recruiting EZH2. Knockdown of DLC1 stimulated cell growth and glycolysis in EC and even mitigated the role of LINC00114 inhibition in EC. In vivo experiment further confirmed the anti-tumor effect of LINC00114 inhibition in EC. CONCLUSION: The data indicate that LINC00114 promotes the development of EC by recruiting EZH2 to enhance H3K27me3 of DLC1.

Comprehensive Analysis of TRP Channel-Related Genes for Estimating the Immune Microenvironment, Prognosis, and Therapeutic Effect in Patients With Esophageal Squamous Cell Carcinoma.

The Nobel Prize in Physiology or Medicine for the year 2021 was awarded to Ardem Patapoutian and David Julius for their discoveries of temperature-sensitive receptors (TRP channels) and tactile receptors (Piezo channels), both of which were previously unknown. TRP channels are at the heart of the human ability to detect temperature, and they also play crucial regulatory functions in the occurrence and progression of cancer. Despite this, there have been no research conducted on the prognostic significance of TRP channels in individuals with esophageal squamous cell carcinoma (ESCC). In GEO and TCGA cohorts, unsupervised clustering was first conducted based on 18 TRP channel-associated differentially expressed genes (DEGs) extracted from MSigDB database and KEGG database. Two TRP subtypes were identified and patients in subtype B had the best prognosis among the two subtypes. Significant differences in staging and grading existed among the different subtypes. In GEO cohort, univariate Cox analysis were performed to screen prognosis related genes. A TRP channel-related prognostic signature, which included 7 signature-related genes, was constructed by the least absolute shrinkage and selection operator (LASSO) Cox regression. Patients were divided into a high-risk group and low-risk group by the median risk score. In GEO and TCGA cohorts, Receiver operating characteristic (ROC) curves, principal component analysis (PCA), and univariate and multivariate Cox regression were performed to confirm the validity of signature. Following a more in-depth study of the TME based on the risk signature, it was discovered that the high-risk group had higher immune cell infiltration and lower tumor purity, indicating a bad prognosis. Patients with high risk scores also had increased immune checkpoint expression, indicating that these patients may be more likely to benefit from immunotherapy than other patients. We also found that paclitaxel, cisplatin, and 5-fluorouracil displayed a better response in treating the low-risk score ESCC patients. This study also adopted GTEx and qRT-PCR to perform experimental verification processes. In summary, we identified a TRP channel-associated prognostic signature. This signature can predict prognosis and immune microenvironment in ESCC.

miR-493 by regulating of c-Jun targets Wnt5a/PD-L1-inducing esophageal cancer cell development.

BACKGROUND: Esophageal cancer is one of the most common cancers across the globe; the 5-year survival of esophageal cancer patients is still low. MicroRNA (miRNA) dysregulation has been implicated in cancer development, and the miRNAs play a pivotal role in esophageal cancer pathogenesis. It is urgently needed to find out how miRNA dysregulation was involved in esophageal cancer (EC) development. METHODS: Through experiments in vivo and in vitro, we explored potential signaling pathways, miR-493/Wnt5A/c-JUN loop, in EC. Their mechanistic roles in EC cell proliferation, migration, and invasion were investigated through multiple validation steps in EC9706 and TE13 cell lines and EC specimens. RESULTS: Overexpression of miR-493 attenuates esophageal cancer cell proliferation, migration, and invasion in vivo and in vitro. Moreover, miR-493 downregulation is an unfavorable factor in EC and negatively correlated with Wnt5A. The existence of miR-493 is also an important attribute of metabolism. Based on mechanism analyses, we show that miR-493 inhibits the activity of c-JUN and p-PI3K/p-AKT with enhanced p21 and directly regulates Wnt5A expression and function, whereas c-JUN binds the promoter region of miR-493 and suppressed the expression of miR-493, forming a negative feedback loop. CONCLUSIONS: The miR-493/Wnt5A/c-JUN loop is a molecular feedback loop that refers to the development of esophageal cancer cells and a potential target for the treatment of esophageal cancer.

Exosomal lncRNA ZFAS1 regulates esophageal squamous cell carcinoma cell proliferation, invasion, migration and apoptosis via microRNA-124/STAT3 axis.

BACKGROUND: In recent years, long non-coding RNAs (lncRNAs) are of great importance in development of different types of tumors, while the function of lncRNA ZFAS1 is rarely discussed in esophageal squamous cell carcinoma (ESCC). Therefore, we performed this study to explore the expression of exosomal lncRNA ZFAS1 and its molecular mechanism on ESCC progression. METHODS: Expression of ZFAS1 and miR-124 in ESCC tissues was detected. LncRNA ZFAS1 was silenced to detect its function in the biological functions of ESCC cells. A stable donor and recipient culture model was established. Eca109 cells transfected with overexpressed and low expressed ZFAS1 plasmid and miR-124 inhibitor labeled by Cy3 were the donor cells, and then co-cultured with recipient cells to observe the transmission of Cy3-ZFAS1 between donor cells and recipient cells. The changes of cell proliferation, apoptosis, invasion, and migration in recipient cells were detected. The in vivo experiment was conducted for verifying the in vitro results. RESULTS: LncRNA ZFAS1 was upregulated and miR-124 was down-regulated in ESCC tissues. Silencing of ZFAS1 contributed to suppressed proliferation, migration, invasion and tumor growth in vitro and induced apoptosis of ESCC cells. LncRNA ZFAS1 was considered to be a competing endogenous RNA to regulate miR-124, thereby elevating STAT3 expression. Exosomes shuttled ZFAS1 stimulated proliferation, migration and invasion of ESCC cells and restricted their apoptosis with increased STAT3 and declined miR-124. Furthermore, in vivo experiment suggested that elevated ZFAS1-exo promoted tumor growth in nude mice. CONCLUSION: This study highlights that exosomal ZFAS1 promotes the proliferation, migration and invasion of ESCC cells and inhibits their apoptosis by upregulating STAT3 and downregulating miR-124, thereby resulting in the development of tumorigenesis of ESCC.

AKAP4 mediated tumor malignancy in esophageal cancer.

AKAP4 as a new Cancer/Testis (CT) antigen is expressed not only in human germ cells, but also expressed in various tumor cells. AKAP4 is correlated with tumor malignancy; however, the role of AKAP4 in esophageal cancer remains unknown. Here we explored the function of AKAP4 in esophageal cancer. We found that AKAP4 mRNA and protein levels were up-regulated in the esophageal cancer tissues compared to normal control. In KYSE150 cell line, inhibition of AKAP4 suppressed cell growth and invasiveness. Overexpression of AKAP4 promoted cell growth and invasiveness. In addition, expression of epithelial markers (E-cadherin and ZO-1) was up-regulated or down-regulated and expression of mesenchymal markers (vimentin and N-cadherin) was down-regulated or up-regulated after knockdown or overexpression of AKAP4 in vitro. In vivo in a xenograft model silencing AKAP4 suppressed tumor growth. We also found that NF-κB p65 bound to AKAP4 promoter and regulated expression of AKAP4. In conclusion, overexpression of AKAP4 is associated with esophageal cancer progression. Inhibition of AKAP4 leads to suppressed growth and invasion of esophageal cancer.

Modulation of E-cadherin expression promotes migration ability of esophageal cancer cells.

Losing the E-cadherin plays an important role in the metastasis of cancer. The regulation of the expression of E-cadherin is unclear. Circadian rhythm alteration is associated with the pathogenesis of a number of cancers. This study aims to investigate the role of one of the circadian proteins, period-2 (Per2) in repressing the expression of E-cadherin in esophageal cancer (esophageal cancer). We observed that the levels of circadian protein Per2 were significantly increased and E-cadherin was significantly decreased in the tissue of human esophageal cancer with metastasis as compared with non-metastatic esophageal cancer. Overexpression of Per2 in the esophageal cancer cells markedly repressed the expression of E-cadherin. The pHDAC1 was detected in human esophageal cancer with metastasis, which was much less in the esophageal cancer tissue without metastasis. Overexpression of Per2 increased the levels of pHDAC1 as well as the E-cadherin repressors at the E-cadherin promoter locus. Overexpression of Per2 markedly increased the migratory capacity of esophageal cancer cells, which was abolished by the inhibition of HDAC1. We conclude that Per-2 plays an important role in the esophageal cancer cell metastasis, which may be a novel therapeutic target for the treatment of esophageal cancer.

Low expression of KLF17 is associated with tumor invasion in esophageal carcinoma.

PURPOSE: KLF17 belongs to the Sp/KLF zinc-finger protein family as a regulator in tumor development. However, its expression and biologic function has remained unclear in EC. METHODS: The esophageal carcinoma tissue samples and adjacent normal tissues were obtained from the Second Hospital of Hebei Medical University. Immunohistochemistry, Western blot, and transfection were applied to evaluate the expression and clinical significance of KLF17 in esophageal cancer. RESULTS: In this study, we showed that KLF17 was overexpressed in esophageal normal samples compared to the cancer. Moreover, KLF17 was upregulated at lymph node non-metastatic cancer tissues when compared to metastatic cancer tissues. KLF17 overexpression decreased EC cell proliferation, migration and invasion ability. In contrast, the knockdown of KLF17 increased EC cell proliferation, migration and invasion ability. CONCLUSION: These results suggest that KLF17 inhibits tumor development and may serve as a potential therapeutic target.

MiR-133a suppresses the migration and invasion of esophageal cancer cells by targeting the EMT regulator SOX4.

MicroRNAs (miRNAs) are small, non-coding RNAs which can function as oncogenes or tumor suppressor genes in human cancers. In the present study, we demonstrated that the expression ofmiR-133a was dramatically decreased in examined esophageal squamous cell carcinoma (ESCC) cell lines and clinical ESCC tissue samples. Additionally, miR-133a expression was inversely correlated with tumor progression in ESCCs. We have found that over-expression of miR-133a significantly suppressed the proliferation, migration and invasion of ESCC cells in vitro. miR-133a over-expression also significantly suppressed the aggressive phenotype of ESCC in vivo, suggesting that miR-133a may function as a novel tumor suppressor. Further studies indicated that the EMT-related transcription factor Sox4 was a direct target gene of miR-133a, evidenced by the direct binding of miR-133a with the 3'UTR of Sox4. Notably, the EMT marker E-cadherin or vimentin, a downstream of Sox4, was also down-regulated or upregulated upon miR-133a treatment. We have also shown that over-expressing or silencing Sox4 was able to elevate or inhibit the migration and invasion of ESCC cells, similar to the effect of miR-133a on the ESCC cells. Moreover, knockdown of Sox4 reversed the enhanced migration and invasion mediated by anti-miR-133a. These results demonstrate that miR-133a acts as a tumor suppressor in ESCC through targeting Sox4 and the EMT process. miR-133a may serve as a potential target in the treatment of human esophageal cancer.

Anatomical and physiological responses of Colorado blue spruce to vehicle exhausts.

In order to examine whether the leaves of the Colorado blue spruce (Picea pungens) are damaged or not by traffic pollution, the traits of the anatomy and physiology of its leaves are investigated by exposure to vehicle exhausts in a laboratory experiment lasting 30 days. The results show that both the anatomical structures and physiological traits of the leaves are significantly affected by vehicle exhausts. The anatomical structures, including epidermis, cuticle, palisade, and spongy parenchyma are modified when exposed to the high concentrations (≥ 0.4 mg/m(3)) of vehicle exhausts. However, physiological traits such as total chlorophyll content are not changed when exposed to different concentrations of vehicle exhaust. Unlike the total chlorophyll content, the electrical conductivities increased, whereas the POD activities decreased when presented in vehicle exhausts. The present study indicates that the Colorado blue spruce changes its anatomical structures and physiological traits to avoid possible damage by vehicle exhausts.

Total petroleum hydrocarbons and heavy metals in the surface sediments of Bohai Bay, China: long-term variations in pollution status and adverse biological risk.

Surface sediments collected from 2001 to 2011 were analyzed for total petroleum hydrocarbons (TPH) and five heavy metals. The sediment concentration ranges of TPH, Zn, Cu, Pb, Cd and Hg were 6.3-535 µg/g, 58-332 µg/g, 7.2-63 µg/g, 4.3-138 µg/g, 0-0.98µg/g, and 0.10-0.68 µg/g, respectively. These results met the highest marine sediment quality standards in China, indicating that the sediment was fairly clean. However, based on the effects range-median (ERM) quotient method, the calculated values for all of the sampling sites were higher than 0.10, suggesting that there was a potential adverse biological risk in Bohai Bay. According to the calculated results, the biological risk decreased from 2001 to 2007 and increased afterwards. High-risk sites were mainly distributed along the coast. This study suggests that anthropogenic influences might be responsible for the potential risk of adverse biological effects from TPH and heavy metals in Bohai Bay.

[Carbon storage of Pinus thunbergii and Robinia pseudoacacia plantations on Nanchangshan Island, Changdao County of Shandong Province, China].

Using indigenous tree species to transform large area pure plantations has been an effective close-to-nature forest management mode in China islands. By using the biomass allometric equation and combined with the investigation data from sampling plots, the carbon storage of the dominant species Pinus thunbergii and Robinia pseudoacacia in the plantations on the Nanchangshan Island of Miaodao Archipelago in Changdao County of Shandong Province was estimated. The average carbon storage in the arbor layer of P. thunbergii and R. pseudoacacia plantations was 56.81 and 37.26 t x hm(-2), respectively, being higher than the average carbon stock (27.62 t x hm(-2)) of tree plantations in Shandong Province. Slope aspect and stand density were the important environmental and biological factors affecting the tree's carbon stock in the Island, respectively. There was no significant correlation between the average cumulative rate of biomass in the arbor layer of P. thunbergi plantation and the stand age. The P. thunbergii with good carbon sequestration function could be an ideal tree species on Nanchangshan Island.

Hexabromocyclododecanes in limnic and marine organisms and terrestrial plants from Tianjin, China: diastereomer- and enantiomer-specific profiles, biomagnification, and human exposure.

To interpret the distribution of hexabromocyclododecanes (HBCDs) in various organisms, we measured the concentrations and diastereomer and enantiomer profiles of HBCDs in 21 different species of limnic and marine cohorts from Tianjin, China. The concentration ranges of HBCDs in limnic and marine organisms were 64.3-1111 ng g(-1) lw and 85.5-989 ng g(-1) lw, respectively. Living habitat and feeding habits had important impacts on HBCD diastereomer distribution. Most of the species appeared to preferentially select (+)-α-, (-)-ß- and (-)-γ-HBCD. There is a tendency that the total and α-HBCDs were magnified as trophic level increased with trophic magnification factors (TMFs) around 2. The concentrations of HBCDs in the limnic and marine fishes were highest in the liver, followed by the gill, skin, and muscle. In terrestrial plants, the highest concentrations of HBCDs were observed in the leaf, followed by the root and the rhizosphere soil. Plants showed enantioselectivity for HBCD enantiomers, which varied with plant species and organs (leaf vs. root) of the same plant. Higher estimated daily intakes (EDIs) of HBCDs were observed from fish than from wheat.

Application of macrobenthos functional groups to estimate the ecosystem health in a semi-enclosed bay.

In this study, the functional group concept was first applied to evaluate the ecosystem health of Bohai Bay. Macrobenthos functional groups were defined according to feeding types and divided into five groups: a carnivorous group (CA), omnivorous group (OM), planktivorous group (PL), herbivorous group (HE), and detritivorous group (DE). Groups CA, DE, OM, and PL were identified, but the HE group was absent from Bohai Bay. Group DE was dominant during the study periods. The ecosystem health was assessed using a functional group evenness index. The functional group evenness values of most sampling stations were less than 0.40, indicating that the ecosystem health was deteriorated in Bohai Bay. Such deterioration could be attributed to land reclamation, industrial and sewage effluents, oil pollution, and hypersaline water discharge. This study demonstrates that the functional group concept can be applied to ecosystem health assessment in a semi-enclosed bay.

[Phytoplankton assemblages and their relation to environmental factors by multivariate statistic analysis in Bohai Bay].

A detailed field survey of hydrological, chemical and biological resources was conducted in the Bohai Bay in spring and summer 2007. The distributions of phytoplankton and their relations to environmental factors were investigated with multivariate analysis techniques. Totally 17 and 23 taxa were identified in spring and summer, respectively. The abundance of phytoplankton in spring was 115 x 10(4) cells x m(-3), which was significantly higher than that in summer (3.1 x 10(4) cells x m(-3)). Characteristics of phytoplankton assemblages in the two seasons were identified using principal component analysis (PCA), while redundancy analysis (RDA) was used to examine the environmental variables that may explain the patterns of variation of the phytoplankton community. Based on PCA results, in the spring, the phytoplankton was mainly distributed in the center and northern water zone, where the nitrate nitrogen concentration was higher. However, in summer, phytoplankton was found distributed in all zones of Bohai Bay, while the dominant species was mainly distributed in the estuary. RDA indicated that the key environmental factors that influenced phytoplankton assemblages in the spring were nitrate nitrogen (NO3(-) -N), nitrite nitrogen (NO2(-) -N) and soluble reactive phosphorus (SRP), while ammonium nitrogen (NH4(+) -N) and water temperature (WT) played key roles in summer.

Dickkopf-1 is oncogenic and involved in invasive growth in non small cell lung cancer.

Dickkopf-1 (DKK1) is an inhibitor of the Wnt/ß-catenin signaling pathway. However, the role of DKK1 in the progression of non small cell lung cancer (NSCLC) is not fully understood. In this study, RT-PCR and Western blot were used to examine the expression of DKK1 in a panel of ten human NSCLC cell lines and NSCLC tissues. DKK1 expression was highly transactivated in the great majority of these cancer lines. The expression of DKK1 was upregulated on both mRNA and protein levels in NSCLC tissues compared with the adjacent normal lung tissues. Immunohistochemistry and immunofluoresence revealed that DKK1 was mainly distributed in the cytoplasm in both carcinoma tissues and cell lines. DKK1 protein expression was also evaluated in paraffin sections from 102 patients with NSCLC by immunohistochemistry, and 65(63.73%)tumors were DKK1 positive. Relative analysis showed a significant relationship between DKK1 positive expression and lymph node metastasis(P<0.05). Patients with DKK1-positive tumors had poorer DFS than those with negative ESCC (5-year DFS; 15.4% versus 27%, P = 0.007). To further explore the biological effects of DKK1 in NSCLC cells, we over-expressed DKK1 in NSCLC 95C cell using eukaryotic expression vector pCMV-Tab-2b and performed a knockdown of DKK1 in LTEP-a-2 cell using a short hairpin RNA expression vector pSilencer 5.1. DKK1 did not have any effect on proliferation, but seemed to play a role in migration and invasion capability. Overexpression of DKK1 promotes migratory and invasive activity of 95C, while DKK1 knockdown resulted in the suppression of migration and invasion potentials of LTEP-a-2 cell. Taken together, these results indicate that DKK1 may be a crucial regulator in the progression of NSCLC. DKK1 might be a potential therapeutic target in NSCLC.

Distribution and controlling factors of phytoplankton assemblages in a semi-enclosed bay during spring and summer.

The phytoplankton assemblages' patterns and their correlation to environmental factors were studied in Bohai Bay during spring and summer. Two zones, the northern (NWA) and southern (SWA) water area, were identified by cluster analysis based on their physical and chemical properties. Principal component analysis (PCA) showed that more phytoplankton species was found in the SWA with low nutrient concentration, while high phytoplankton abundance occurred in the NWA with high nutrient concentration. The seasonal variability in phytoplankton can be explained by water temperature, nutrient, and hydrodynamic conditions (includes mixing during spring and stratification during summer). Results of redundancy analysis (RDA) showed that silicate (SiO(4)) and soluble reactive phosphorus (SRP) were the most important environmental factors influencing the phytoplankton distribution during spring and summer, respectively. Hydrodynamics condition plays a key role in controlling variation of the environmental factors, which determined phytoplankton distribution in Bohai Bay.

PAHs distribution in sediments associated with gas hydrate and oil seepage from the Gulf of Mexico.

Six sediment samples collected from the Gulf of Mexico were analyzed. Total concentrations of the PAHs ranged from 52 to 403 ng g(-1) dry weight. The lowest PAH concentration without 5-6 rings PAHs appeared in S-1 sample associated with gas hydrate or gas venting. Moreover, S-1 sample had the lowest organic carbon content with 0.85% and highest reduced sulfur level with 1.21% relative to other samples. And, analysis of the sources of PAHs in S-1 sample indicated that both pyrogenic and petrogenic sources, converserly, while S-8, S-10 and S-11 sample suggested petrogenic origin. The distribution of dibenzothiophene, fluorine and dibenzofuran and the maturity parameters of triaromatic steranes suggested that organic matters in S-1 sample were different from that in S-8, S-10 and S-11 sample. This study suggested that organic geochemical data could help in distinguish the characteristic of sediment associated with gas hydrate or with oil seepage.