Shifts in species dominance related to spatial assemblages and variation in environmental parameters in a tropical mangrove estuary

A shift in species dominance in the mangrove microalgae community in Cross River Estuary System (CRES), Nigeria, was carried out during the wet season to highlight the microalgae structure, identify potential indicators, and evaluate the water quality variation. Plankton samples were collected at sixteen selected sampling sites along the river. Diatoms showed the highest number of species (240 species), contributing more than 70% of the total microalgae abundance. Cluster analysis of the microalgae community delimits the CRES into three sections; upper (UCRS), middle (MCRS), and lower (LCRS) communities. The spatial shift in the microalgae community showed that the green algae (Eudorina elegans and Hylotheca dissiliens) dominated the UCRS communities, while diatoms dominated the MCRS (Polymyxus coronalis and Actinocyclus normanii) and LCRS (A. normanii and A. octonarius). The principal component analysis showed that the UCRS was influenced by turbidity and nitrate, while the MCRS and LCRS were characterized by phosphate, electrical conductivity, and salinity/total dissolved solids. The similarity percentage (SIMPER) analysis showed that Surirella tenera and Hylotheca dissiliens contributed >3.5% inter site dissimilarity between the UCRS and LCRS microalgae community. The redundancy analysis revealed that some microalgae species such as Odontella mobiliensis, Coscinodiscopsis jonesiana, A. normanii, and A. octonarius responded positively to salinity change and ammonia concentration in the estuary, while S. tenera, P. coronalis, Bacillaria paxilifer, Navicula transitans, Cyclotella meneghiniana, Humidophila contenta, Melosira granulata, Aulacoseira herzogii, Eudorina elegans, H. dissiliens, Mougeotia sp., and Dinobryon sertularia responded positively to turbidity, nitrate, and phosphate concentration. This study illustrates that CRES inhabit rich biodiversity of microalgae which some taxa could be used as indicators of the environmental changes in marine waters.

[Effects of rapid drug sensitivity testing for multidrug-resistant bacteria on the prognosis of patients with severe intra-abdominal infection]

Objective: To examine the clinical value of rapid detection of drug-resistant bacteria by immunochromatography and the effects of rapid detection on the prognosis of patients with severe intra-abdominal infection complicated by carbapenem-resistant Enterobacteriaceae (CRE) bloodstream infection. Methods: This was a retrospective cohort study. We analyzed clinical data of 73 patients with severe abdominal infections with sepsis or septic shock complicated by CRE bloodstream infection admitted to the general surgery department of Jinling Hospital between February 2022 and February 2023. Patients were divided into a colloidal gold immunochromatographic assay (GICA) group (17 patients) and conventional testing group (56 patients) based on whether a GICA for CRE had been performed on the patients' first blood culture sample during the diagnosis and treatment process. There were no statistically significant differences between the GICA and conventional testing groups in age ([55.9±17.3] vs. [47.6±16.4] years), sex ([16 men vs. one woman ] vs. [41 men vs. 15 women]), median Charlson comorbidity index (3.0[2.0,4.0] vs. 3.0[2.0, 4.8]), septic shock (10 vs. 39), or acute kidney injury (8 vs. 40) (all P>0.05). Both groups routinely underwent traditional bacterial identification and drug susceptibility testing. Additionally, patients in the GICA group were tested directly for positive blood cultures using a GICA carbapenemase test kit. The main outcomes were mortality rates on Days 28 and 90 after the first identification of CRE bloodstream infection in both groups. We also compared the microbial clearance rate, duration of hospitalization and intensive care unit stay, and time from onset of CRE bloodstream infection to initiation of targeted and appropriate antibiotics between the two groups. Results: The rate of microbial clearance of bloodstream infection was significantly greater in the GICA group than in the conventional testing group (15/17 vs. 34/56 [60.7%], χ2=4.476, P=0.034), whereas the 28-day mortality tended to be lower in the GICA than conventional testing group [5/17 vs. 44.6% [25/56], χ2=1.250, P=0.264). The 90-day mortality (8/17 vs. 53.6% [30/56], χ2=0.222, P=0.638), median duration of hospitalization (37.0 [18.0, 46.5] days vs. 45.5 [32.2, 64.8] days, Z=-1.867, P=0.062), and median duration of intensive care unit stay (18.0 [6.5, 35.0] days vs. 32.0 [5.0, 51.8] days, Z=-1.251, P=0.209). The median time between the onset of bloodstream infection and administration of antibiotics was 49.0 (38.0, 69.0) hours in the GICA group, which is significantly shorter than the 163.0 (111.8, 190.0) hours in the conventional testing group (Z=-5.731, P<0.001). The median time between the onset of bloodstream infection and administration of appropriate antibiotics was 40.0 (34.0, 80.0) hours in the GICA group, which is shorter than in the conventional testing group (68.0 [38.2, 118.8]) hours; however, this difference is not statistically significant (Z=-1.686, P=0.093). Conclusions: GICA can provide information on carbapenemase- producing pathogens faster than traditional drug sensitivity testing, enabling early administration of the optimal antibiotics. The strategy of 'carbapenemase detection first' for managing bacterial infection has the potential to improve prognosis of patients and reduce mortality rate.

Polymeric carbohydrates utilization separates microbiomes into niches: insights into the diversity of microbial carbohydrate-active enzymes in the inner shelf of the Pearl River Estuary, China

Polymeric carbohydrates are abundant and their recycling by microbes is a key process of the ocean carbon cycle. A deeper analysis of carbohydrate-active enzymes (CAZymes) can offer a window into the mechanisms of microbial communities to degrade carbohydrates in the ocean. In this study, metagenomic genes encoding microbial CAZymes and sugar transporter systems were predicted to assess the microbial glycan niches and functional potentials of glycan utilization in the inner shelf of the Pearl River Estuary (PRE). The CAZymes gene compositions were significantly different between in free-living (0.2-3 μm, FL) and particle-associated (>3 μm, PA) bacteria of the water column and between water and surface sediments, reflecting glycan niche separation on size fraction and selective degradation in depth. Proteobacteria and Bacteroidota had the highest abundance and glycan niche width of CAZymes genes, respectively. At the genus level, Alteromonas (Gammaproteobacteria) exhibited the greatest abundance and glycan niche width of CAZymes genes and were marked by a high abundance of periplasmic transporter protein TonB and members of the major facilitator superfamily (MFS). The increasing contribution of genes encoding CAZymes and transporters for Alteromonas in bottom water contrasted to surface water and their metabolism are tightly related with particulate carbohydrates (pectin, alginate, starch, lignin-cellulose, chitin, and peptidoglycan) rather than on the utilization of ambient-water DOC. Candidatus Pelagibacter (Alphaproteobacteria) had a narrow glycan niche and was primarily preferred for nitrogen-containing carbohydrates, while their abundant sugar ABC (ATP binding cassette) transporter supported the scavenging mode for carbohydrate assimilation. Planctomycetota, Verrucomicrobiota, and Bacteroidota had similar potential glycan niches in the consumption of the main component of transparent exopolymer particles (sulfated fucose and rhamnose containing polysaccharide and sulfated-N-glycan), developing considerable niche overlap among these taxa. The most abundant CAZymes and transporter genes as well as the widest glycan niche in the abundant bacterial taxa implied their potential key roles on the organic carbon utilization, and the high degree of glycan niches separation and polysaccharide composition importantly influenced bacterial communities in the coastal waters of PRE. These findings expand the current understanding of the organic carbon biotransformation, underlying the size-fractionated glycan niche separation near the estuarine system.

[Expression and functional SNP loci screen of ATM from coal worker's pneumoconiosis]

Objective: To detect of gene expression and genotype of the ataxia telangiectasia mutated (ATM) from coal workers' pneumoconiosis (CWP) , It is explored whether CWP is related to ATM gene. Methods: In October 2020, the relevant information of 264 subjects who received physical examination or medical treatment in the Department of occupational diseases of Guiyang public health treatment center from January 2019 to September 2020 was collected. Through the occupational health examination, 67 healthy people with no history of exposure to occupational hazards were selected as the healthy control group; The coal miners with more than 10 years of coal dust exposure history and small shadow in the lung but not up to the diagnostic criteria were the dust exposure control group, a total of 66 people; The patients with the same history of coal dust exposure and confirmed stage I were coal worker's pneumoconiosis stage I group, a total of 131 people. The expression of ATM was detected by QRT PCR. ATM rs189037 and rs1801516 were genotyped by massarray. Results: There was significant difference in the expression of ATM among the groups (P<0.05) ; Compared with the healthy control group, the expression of ATM in the dust exposed control group was significantly increased (P<0.05) . With the occurrence and development of CWP, the GG of rs189037 wild type decreased, the GA of mutant heterozygote and AA of homozygote increased, but the difference was not statistically significant (P>0.05) ; Rs1801516 wild type GG and mutant heterozygote GA had no significant changes (P>0.05) . There were significant differences in age, neutrophils and basophils among rs189037 groups (all P<0.05) . There were no significant differences in blood pressure, eosinophils, lymphocytes, monocytes, smoking and drinking history among rs189037 groups (all P>0.05) . Compared with wild-type GG, the or of mutant heterozygotes and homozygotes increased, but the differences were not statistically significant (P>0.05) . Conclusion: ATM gene may be one of the early activation genes of CWP and rs189037 may be the functional loci which affects gene expression. ATM gene is related to inflammatory response, Neutrophils and basophils have an impact on the development of CWP.

Bacterial community variations in the South China Sea driven by different chemical conditions

In this study, Illumina MiSeq sequencing of the 16 S rRNA gene was used to describe the bacterial communities in the South China Sea (SCS) during the southwest monsoon period. We targeted different regions in the SCS and showed that bacterial community was driven by the effects of the river, upwelling, and mesoscale eddy through changing the environmental factors (salinity, temperature, and nutrients). Distinct bacterial communities were observed among different chemical conditions, especially between the estuary and the open sea. The abundance of Burkholderiales, Frankiales, Flavobacteriales, and Rhodobacterales dominated the estuary and its adjacent waters. Bacteria in cyclonic eddy were dominated by Methylophilales and Pseudomonadales, whereas Prochlorococcus, SAR11 clade, and Oceanospirillales had relatively high abundance in the anticyclonic eddy. Overall, the abundance of specific phylotypes significantly varied among samples with different chemical conditions. Chemical conditions probably act as a driver that shapes and controls the diversity of bacteria in the SCS. This study suggests that the interaction between microbial and environmental conditions needs to be further considered to fully understand the diversity and function of marine microbes.

Assessing ecological health of mangrove ecosystems along South China Coast by the pressure-state-response (PSR) model

The pressure-state-response (PSR) model was applied to establish a mangrove ecosystem health evaluation system combined with analytical hierarchy process (AHP) in this paper. The mangrove wetlands are divided into five ecological levels: excellent health, good health, health, sub-health and morbidity, which is based on the comprehensive health index (CHI) value. Twelve representative sites were selected for sampling to assess the ecological health condition of mangroves. As a result, the ecological health level of Gaoqiao mangrove area is excellent health; the ecological health level of Taiping mangrove area is good health; the ecological health level of Huguang and Qi'ao mangrove area is health; the ecological health level of Techeng and He'an mangrove area is sub-health; the ecological health level of Huidong mangrove area is morbidity. These results will give some advises for ecological protection and biological resource sustainable development of mangrove ecosystem in China.

Distribution patterns and source identification for heavy metals in Mirs Bay of Hong Kong in China

Sediment quality caused by heavy metals was investigated in the Mirs Bay and Tolo Harbor, Hong Kong, China. Samples were collected in January and July, 2010. One-way analysis of variance showed that sediment quality variables (Fe, Zn, Mn, Pb, V, Cu, Cr, Ba, Ni and As) were significantly different (p < 0.05) among the sampling areas, whereas the average concentration of V, Eh and Ba exhibited the significant seasonal variations (p < 0.05) between January and July. The spatial pattern of heavy metals (Pb, Zn and Cu) can probably be attributed to anthropogenic and tidal flushing influence in the harbor. Both geo-accumulation index (I_geo) and enrichment factor (EF) were used to identify the metal pollution level and its related source. Pb, Zn, and Cu are considered as "polluted metal" in Tolo Harbor. Cluster analysis (CA) identified three distinct clusters with the Tolo Habor and Shatou Jiao, the inner bay and the south part of the bay. Principal component analysis (PCA) identified the spatial patterns and their affected parameters in the studying area. Results showed metals distribution in Mirs Bay and its adjacent area is principally affected by human activities such as marineculture, dumping, located mostly in Tolo Harbor and Shatou Jiao, where was closely related with anthropogenic influence. While the monitoring stations including MS13-MS16 and MS8 locating in the south part of the studying area might be corresponded to natural influence.

Mixture of Pb, Zn and Cu on root permeability and radial oxygen loss in the mangrove Bruguiera gymnorrhiza

A short term pot trail was employed to evaluate the exposure of mixed heavy metals (Cu, Pb and Zn) on growth, radial oxygen loss (ROL) and root anatomy in Bruguiera gymnorrhiza. The possible function of BgC4H, a cytochrome P450 gene, on root lignification was also discussed. The exposures of mixed Cu, Pb and Zn directly reduce O₂ leakage at root surface. The reduced ROL inhibited by heavy metals was mainly ascribed by the changes in root anatomical features, such as decreased root porosity together with increased lignification within the exodermis. BgC4H was found to be up-regulated after 0.5-day metal exposure, and remained higher transcript levels within 3-day metal exposure when compared to control roots. Besides, the inhibited photosynthesis may also result in less oxygen can be transported to the underground roots. In summary, the mangrove B. gymnorrhiza appeared to react to external mixed metal contaminants by developing a lignified and impermeable exodermis, and such a root barrier induced by mixed Cu, Pb and Zn appeared to be an adaptive response to block metal ions enters into the roots.

Phytoplankton community, structure and succession delineated by partial least square regression in Daya Bay, South China Sea

Daya Bay is facing the influence of human activities and nature changes, which result in phytoplankton adjusting to the changing environment. The data about environmental changes and phytoplankton were obtained from four seasonal cruises in 2013 in the bay. It is helpful to explore seasonal succession of phytoplankton driven by the determining environmental factors in this bay. Temperature is a significant indicator of season change. The limiting factor of phytoplankton growth totally changed from P (PO₄-P) limiting during the southwest monsoon to Si (SiO₃-Si) limiting during northeast monsoon. The order of diatoms and dinoflagellates was the dominant phytoplankton groups in Daya Bay. The dominant species included chain-forming diatoms (Skeletonema, Pseudo-nitzschia, Thalassionema, Chaetoceros and Rhizosolenia) were found all the year round and filamentous cyanobacteria (Trichodesmium) in spring and autumn. Partial least square regression (PLS) found that salinity, temperature and nutrients were important driving force for phytoplankton seasonal succession.

Dynamics of radial oxygen loss in mangroves subjected to waterlogging

Tidal flooding can directly result in oxygen (O₂) shortage, however the functions of root aeration in flooding tolerance and O₂ dynamics within mangroves are still poorly understood. Thus, in this study, the correlations among waterlogging tolerance, root porosity and O₂ movement within the plants were investigated using two mangrove species (Aegiceras corniculatum and Bruguiera gymnorrhiza) and a semi-mangrove Heritiera littoralis. Based on the present data, the species A. corniculatum and B. gymnorrhiza, which possessed higher root porosity, exhibited higher waterlogging tolerance, while H. littoralis is intolerant. Increased root porosity, leaf stoma, and total ROL were observed in the roots of A. corniculatum and B. gymnorrhiza growing in stagnant solution when compared to respective aerated controls. As for ROL spatial pattern along roots, external anaerobic condition could promote ROL from apical root regions but reduce ROL from basal roots, leading to a 'tighter barrier'. In summary, the present study indicated that the plants (e.g., A. corniculatum and B. gymnorrhiza) prioritized to ensure O₂ diffusion towards root tips under waterlogging by increasing aerenchyma formation and reducing O₂ leakage at basal root regions.

[Postoperative complications and survival analysis of 1 118 cases of open splenectomy and azygoportal disconnection in the treatment of portal hypertension]

Objective: To analyze the recent postoperative and long-term postoperative complications of open-splenectomy and disconnection in patients with portal hypertension. Methods: There were 1 118 cases with portal hypertension who underwent open splenectomy and azygoportal disconnection from April 2010 to September 2015 at Department of Surgery, People's Liberation Army 302 Hospital. Retrospective case investigation and telephone follow-up were conducted in October 2016. All patients had history of upper gastrointestinal bleeding before operation. Short-term complications after surgery were recorded including secondary laparotomy of postoperative abdominal hemostasis, severe infection, intake disorders, liver insufficiency, postoperative portal vein thrombosis and perioperative mortality. Long-term data including postoperative upper gastrointestinal rebleeding, postoperative survival rate and incidence of postoperative malignancy were recorded, too. GraphPad Prism 5 software for data survival analysis and charting. Results: Postoperative short-term complications in 1 118 patients included secondary laparotomy of postoperative abdominal hemostasis(1.8%, 21/1 118), severe infection(2.9%, 32/1 118), intake disorders(1.0%, 11/1 118), liver dysfunction (1.6%, 18/1 118), postoperative portal vein thrombosis(47.1%, 526/1 118)and perioperative mortality(0.5%, 5/1 118). After phone call following-up, 942 patients' long-term data were completed including 1, 3, 5 years postoperative upper gastrointestinal rebleeding rate(4.4%, 12.1%, 17.2%), 1, 3, 5-year postoperative survival rate(97.0%, 93.5%, 90.3%); the incidence of postoperative malignant tumors in 1, 3 and 5 years were 1.7%, 4.4% and 6.2%. Conclusions: Reasonable choosing of surgical indications and timing, proper performing the surgery process, effective conducting perioperative management of portal hypertension are directly related to the patient's short-term prognosis after portal hypertension. Surgical intervention can reduce the rates of patients with upper gastrointestinal rebleeding, improve survival, and do not increase the incidence of malignant tumors.

[Clinical and molecular analysis of two Chinese siblings with Bloom syndrome]

Objective: To expand the knowledge of the clinical and molecular characteristics of the children with Bloom syndrome. Methods: Clinical data of two siblings with classic Bloom syndrome of Shanghai Children's Medical Center from January 2009 to June 2017 were obtained and analyzed. The DNA of peripheral blood was collected from two Bloom syndrome siblings and their parents during 2015. The mutations were detected with high-throughput sequencing by Illumina sequencing platform. Results: The two siblings (probands) visited our department for short stature and growth retardation, they had full-term normal delivery after normal pregnancy of their mother. Both cases presented with feeding difficulties, malnutrition, microcephaly and mental retardation, repeated infection, symmetrical short stature and special faces. At first, the proband was an 8-year-3-month old girl, her height was 99.7 cm, body mass index (BMI) 12.07 kg/m(2), head circumference was 45.5 cm, and birth weight was 1.6 kg. Her younger brother was 3-year-11-month old, his height was 86.6 cm, BMI was 14 kg/m(2), birth weight was 1.95 kg, and the head circumference reached 36 cm at 16 months. No evidence of cancer and characteristic rash was detected at 8-year follow-up. Pathogenic complex heterozygous mutations c.772_773delCT, p.Leu258Glufs*7 and c.959+ 2T>A in BLM gene were detected in both siblings, which were separately inherited from their unaffected parents. Besides , c.959 + 2T>A has not been reported previously. Conclusions: Children with Bloom syndrome are characterized by short stature, microcephaly, special faces, feeding difficulties, and immunodeficiency. And butterfly erythematous rash may be absent. The c.959+2T>A mutation detected in our patients maybe a novel pathogenic mutation.

[Dynamic variation trend and prognostic value of bronchial wall thickness in severely burned patients combined with inhalation injury]

Objective: To explore the dynamic variation trend of bronchial wall thickness (BWT) in severely burned patients combined with inhalation injury, and to determine the value of BWT to prognosis of patients. Methods: Forty-three severely burned patients with inhalation injury hospitalized in Intensive Burn Department of the Affiliated Hospital of Nankai University (Tianjin No.4 Hospital) from July to November 2016, conforming to the study criteria, were divided into survival group (n=27) and death group (n=16) according to the prognosis of patients within 14 days after admission. All patients underwent fiberoptic bronchoscopy and inhalation injury rating based on abbreviated injury scale at admission. High resolution CT examination was performed in patients of two groups at admission and 24 h post admission, 3, 7, and 14 d post admission to measure the BWT of right superior lobar bronchus trunk opening. Receiver operating characteristic curves of rating of inhalation damage at admission and BWT at admission were drawn to evaluate the predictive value for death of 43 patients. Data were processed with chi-square test, independent sample t test, Wilcoxon rank sum test, analysis of variance for repeated measurement and least-significant difference-t test. Results: (1) The numbers of patients rated as 0, 1, 2, 3, and 4 grade for inhalation injury in survival group and death group were 0, 19, 6, 2, and 0, and 0, 2, 7, 7, and 0, respectively. There were statistically significant differences between the two groups (Z=-3.79, P<0.01). (2) BWT of patients in death group at admission and 24 h post admission, 3, 7, and 14 d post admission was respectively (2.72±0.26), (3.18±0.22), (2.98±0.18), (2.29±0.17), and (1.45±0.21) mm, which was significantly larger than (2.24±0.15), (2.49±0.15), (1.51±0.17), (1.04±0.16), and (1.01±0.13) mm in survival group (t=7.55, 12.14, 27.11, 19.99, 7.11, P<0.01). BWT of patients in survival group and death group at 24 h post admission, 3, 7, and 14 d post admission showed statistically significant difference when compared with that at admission within the corresponding group (t=5.97, 16.63, 28.21, 38.57, 5.34, 3.31, 4.39, 6.48, P<0.01). BWT of patients in survival group and death group on 3, 7, and 14 d post admission was significantly smaller than that at 24 h post admission within the corresponding group (t=22.27, 34.02, 45.03, 2.77, 10.53, 10.59, P<0.01). BWT of patients in survival group and death group on 7 and 14 d post admission was significantly smaller than that on 3 d post admission within the corresponding group (t=10.49, 18.26, 9.57, 11.44, P<0.01). BWT of patients in survival group and death group on 14 d post admission was significantly smaller than that on 7 d post admission within the corresponding group (t=6.97, 6.15, P<0.01). (3) The total areas under ROC curves of inhalation injury rating at admission and BWT at admission for predicting death of 43 patients were 0.880 and 0.956, respectively (with 95% confidence intervals 0.768-0.991, 0.882-1.000, P<0.05). Grade 1.5 and 2.75 mm were respectively chosen as the optimal threshold values of inhalation injury rating at admission and BWT at admission, with sensitivity of 87.50%, 83.33% and specificity of 77.78%, 96.00%, respectively. Conclusions: The BWT of survived and dead patients with severe burn and inhalation injury increases significantly post burn, while the BWT of survived patients restores to normal level faster. BWT can be used to assess the severity of inhalation injury and to predict death in severely burned patients combined with inhalation injury.

Seasonal and spatial variations of water quality and trophic status in Daya Bay, South China Sea

Coastal water quality and trophic status are subject to intensive environmental stress induced by human activities and climate change. Quarterly cruises were conducted to identify environmental characteristics in Daya Bay in 2013. Water quality is spatially and temporally dynamic in the bay. Cluster analysis (CA) groups 12 monitoring stations into two clusters. Cluster I consists of stations (S1, S2, S4-S7, S9, and S12) located in the central, eastern, and southern parts of the bay, representing less polluted regions. Cluster II includes stations (S3, S8, S10, and S11) located in the western and northern parts of the bay, indicating the highly polluted regions receiving a high amount of wastewater and freshwater discharge. Principal component analysis (PCA) identified that water quality experience seasonal change (summer, winter, and spring-autumn seasons) because of two monsoons in the study area. Eutrophication in the bay is graded as high by Assessment of Estuarine Trophic Status (ASSETS).

Spatial and vertical distribution of bacterial community in the northern South China Sea

Microbial communities are highly diverse in coastal oceans and response rapidly with changing environments. Learning about this will help us understand the ecology of microbial populations in marine ecosystems. This study aimed to assess the spatial and vertical distributions of the bacterial community in the northern South China Sea. Multi-dimensional scaling analyses revealed structural differences of the bacterial community among sampling sites and vertical depth. Result also indicated that bacterial community in most sites had higher diversity in 0-75 m depths than those in 100-200 m depths. Bacterial community of samples was positively correlation with salinity and depth, whereas was negatively correlation with temperature. Proteobacteria and Cyanobacteria were the dominant groups, which accounted for the majority of sequences. The α-Proteobacteria was highly diverse, and sequences belonged to Rhodobacterales bacteria were dominant in all characterized sequences. The current data indicate that the Rhodobacterales bacteria, especially Roseobacter clade are the diverse group in the tropical waters.

Assessment for water quality by artificial neural network in Daya Bay, South China Sea

In this study, artificial neural network such as a self-organizing map (SOM) was used to assess for the effects caused by climate change and human activities on the water quality in Daya Bay, South China Sea. SOM has identified the anthropogenic effects and seasonal characters of water quality. SOM grouped the four seasons as four groups (winter, spring, summer and autumn). The Southeast Asian monsoons, northeasterly from October to the next April and southwesterly from May to September have also an important influence on the water quality in Daya Bay. Spatial pattern is mainly related to anthropogenic activities and hydrodynamics conditions. In spatial characteristics, the water quality in Daya Bay was divided into two groups by chemometrics. The monitoring stations (S3, S8, S10 and S11) were in these area (Dapeng Ao, Aotou Harbor) and northeast parts of Daya Bay, which are areas of human activity. The thermal pollution has been observed near water body in Daya Bay Nuclear Power Plant (S5). The rest of the monitoring sites were in the south, central and eastern parts of Daya Bay, which are areas that experience water exchanges from South China Sea. The results of this study may provide information on the spatial and temporal patterns in Daya Bay. Further research will be carry out more research concerning functional changes in the bay ecology with respect to changes in climatic factor, human activities and bay morphology in Daya Bay.

Pb uptake and tolerance in the two selected mangroves with different root lignification and suberization

Metal pollution has been widely reported in mangrove wetlands; however, the mechanisms involved in metal detoxification by mangroves are still poorly understood. This study aimed to investigate the possible function of root lignification/suberization on Pb uptake and tolerance in mangroves. Two mangroves, Acanthus ilicifolius and Rhizophora stylosa with different root lignification/suberization were selected as plant materials; the former exhibits a thin exodermis and low lignification/suberization, while the latter possesses a thick exodermis and high lignification/suberization. A pot trial with addition of Pb was conducted to investigate the differences in Pb uptake and tolerance between the two mangroves. The experiment of rhizobox was designed to explore Pb dynamics and availabilities in the rhizosphere soils, besides, the ability of Pb uptake by the excised roots and X-ray analysis for Pb distribution within roots were also detected. The results revealed that R. stylosa exhibited relatively higher Pb tolerance together with less Pb accumulations when compared to A. ilicifolius. For both species, lower proportion of exchangeable and Carbonate Pb and higher higher Fe-Mn oxides Pb were observed in the rhizosphere zone when compared to the respective non-rhizosphere zone. The results from metal uptake by the excised roots and X-ray analysis clearly showed that the thick lignified/suberized exodermis of R. stylosa could more efficiently delay Pb entering into the roots, leading to less Pb accumulation. In summary, the present study proposes a barrier property of the lignified/suberized exodermis in dealing with the stresses of Pb.

Distribution and sources of the polycyclic aromatic hydrocarbons in the sediments of the Pearl River estuary, China

The Pearl River delta, one of the most prosperous economically region in China, has experienced significant contaminant inputs. However, the dynamics of pollutants in the Pearl River estuary and the adjacent coastal areas are still unclear at present. In the paper, distribution and sources of polycyclic aromatic hydrocarbons (PAHs) were investigated in the surface sediments of the Pearl River estuary. The total PAHs concentrations ranged from 126.08 to 3828.58 ng/g with a mean value of 563.52 ng/g, whereas the highest PAHs were observed in Guangzhou channel. Among the U.S. Environmental Protection Agency's 16 priority PAHs, PAHs with 3-4 rings exhibited relative higher levels. A positive relationship was found between PAHs and total organic carbon. The source analysis further showed that the major sources of PAHs in the Pearl River estuary were originated from the pyrolytic inputs, reflecting a mixed energy structure such as wood, coal and petroleum combustion. In summary, although PAHs in Lingding Bay and the adjacent coastal areas of the Pearl River estuary exhibited a relatively low pollution level, the relatively high pollution level of PAHs in Guangzhou channel will be attended.

Variation of phytoplankton community structure from the Pearl River estuary to South China Sea

The Pearl River is located in the northern part of South China Sea. The environment of the Pearl River estuary (PRE) is significantly impacted by nutrients from anthropogenic activities. Along the anthropogenic pollution gradient from the PRE to South China Sea, the phylogenetic diversity and biomass of phytoplankton was examined in relation to physic-chemical variables. The richness of rbcL gene was higher in the open sea than the estuary, while the concentration of chlorophyll a (Chl a) was higher in the estuary than in the open sea. The cluster analysis of the sequences data resulted in seven phytoplankton community types and the dominant species of phytoplankton changed from Cryptophytes and Diatoms to Prymnesiophytes and Diatoms along the gradient. The community structure of phytoplankton was shaped by nutrients and salinity. The phytoplankton biomass was significantly positively affected by phosphorus, nitrite and ammonium (P < 0.01) but negatively by salinity (P < 0.05); the phytoplankton diversity was highly positively affected by salinity (P < 0.05) but negatively by silicate and nitrate (P < 0.01; P < 0.05, respectively). Anthropogenic activities played a critical role in the phytoplankton distribution and biomass of the study area. Further research is necessary to reveal the influence mechanism of environmental factors on the phytoplankton.

The diversity of coral associated bacteria and the environmental factors affect their community variation

Coral associated bacterial community potentially has functions relating to coral health, nutrition and disease. Culture-free, 16S rRNA based techniques were used to compare the bacterial community of coral tissue, mucus and seawater around coral, and to investigate the relationship between the coral-associated bacterial communities and environmental variables. The diversity of coral associated bacterial communities was very high, and their composition different from seawater. Coral tissue and mucus had a coral associated bacterial community with higher abundances of Gammaproteobacteria. However, bacterial community in seawater had a higher abundance of Cyanobacteria. Different populations were also found in mucus and tissue from the same coral fragment, and the abundant bacterial species associated with coral tissue was very different from those found in coral mucus. The microbial diversity and OTUs of coral tissue were much higher than those of coral mucus. Bacterial communities of corals from more human activities site have higher diversity and evenness; and the structure of bacterial communities were significantly different from the corals collected from other sites. The composition of bacterial communities associated with same coral species varied with season's changes, geographic differences, and coastal pollution. Unique bacterial groups found in the coral samples from more human activities location were significant positively correlated to chemical oxygen demand. These coral specific bacteria lead to coral disease or adjust to form new function structure for the adaption of different surrounding needs further research.

Identification of Surface Water Quality along the Coast of Sanya, South China Sea

Principal component analysis (PCA) and cluster analysis (CA) are utilized to identify the effects caused by human activities on water quality along the coast of Sanya, South China Sea. PCA and CA identify the seasonality of water quality (dry and wet seasons) and polluted status (polluted area). The seasonality of water quality is related to climate change and Southeast monsoons. Spatial pattern is mainly related to anthropogenic activities (especially land input of pollutions). PCA reveals the characteristics underlying the generation of coastal water quality. The temporal and spatial variation of the trophic status along the coast of Sanya is governed by hydrodynamics and human activities. The results provide a novel typological understanding of seasonal trophic status in a shallow, tropical, open marine bay.

Metal (Pb, Zn and Cu) uptake and tolerance by mangroves in relation to root anatomy and lignification/suberization

Metal pollution has been widely reported in mangrove wetlands; however, the mechanisms involved in metal detoxification by mangroves are still poorly understood. This study aimed to investigate the possible function of root anatomy and lignification/suberization on metal uptake and tolerance in seedlings of six species of mangroves. The results revealed that the three rhizophoraceous species (Bruguiera gymnorrhiza (L.) Poir, Kandelia obovata Sheue, Liu & Yong and Rhizophora stylosa Griff) consistently exhibited higher metal tolerances than the three pioneer species (Aegiceras corniculatum (Linn.) Blanco, Acanthus ilicifolius L. and Avicennia marina (Forsk.) Viern.). Moreover, metal-tolerant species often exhibited a thick exodermis with high lignification and suberization. The tolerance indices of the mangroves were found to be positively correlated with the amounts of lignin and suberin deposition within the exodermal cell walls. The observed metal uptake by the excised roots further illustrated that a lignified/suberized exodermis directly delayed the entry of metals into the roots, and thereby contributed to a higher tolerance to heavy metals. In summary, the present study proposes a barrier property of the lignified/suberized exodermis in dealing with the stresses of heavy metals, such that the mangroves which possessed more extensive lignification/suberization within the exodermis appeared to exhibit higher metal tolerance.

Hierarchical structure and crystal orientation in poly(ethylene oxide)/clay nanocomposite films

Water-cast nanocomposite films formed by poly(ethylene oxide) (PEO) and Laponite clay were found to display three characteristic levels of structure with large-scale orientation. The first level with the length scale of ca. 30-50 nm was the clay lamellar bundles, which tended to stack perpendicularly to the film surface. The second level with the characteristic length of 1.8 nm was associated with the alternating stacking of the silicate layers and the PEO chains sandwiched between them. The preferred orientations of these two levels of structure were independent of clay content, solvent removal rate for the film preparation, and the crystallization temperature of the PEO chains situating outside the clay bundles. The third level of structure was characterized by the preferred orientation of the PEO crystalline stems with respect to the surface of the silicate layers. Perpendicular orientation always dominated in the nanocomposite films prepared by slow solvent removal irrespective of crystallization temperature. In the films prepared by fast solvent removal, however, parallel crystal orientation set in as the clay concentration exceeded ca. 33 wt %. The preferred crystal orientation was ascribed to the confinement effect imposed by the clay bundles to the crystallization of the PEO chains situating in the interbundle region. In the films cast by slow solvent removal, the weaker confinement associated with the larger interbundle distance led to perpendicular crystal orientation. When the interbundle distance was reduced to ca. 30 nm in the films prepared by rapid solvent evaporation, the strong confinement directed the crystals to form parallel orientation.

Bacterial polycyclic aromatic hydrocarbon ring-hydroxylating dioxygenases in the sediments from the Pearl River estuary, China

Bacterial community compositions were characterized using denaturing gradient gel electrophoresis analysis of bacterial 16S rRNA gene in the sediments of the Pearl River estuary. Sequencing analyses of the excised bands indicated that Gram-negative bacteria, especially Gammaproteobacteria, were dominant in the Pearl River estuary. The diversity of polycyclic aromatic hydrocarbon ring-hydroxylating dioxygenase (PAH-RHD) gene in this estuary was then assessed by clone library analysis. The phylogenetic analyses showed that all PAH-RHD gene sequences of Gram-negative bacteria (PAH-RHD[GN]) were closely related to the nagAc gene described for Ralstonia sp. U2 or nahAc gene for Pseudomonas sp. 9816-4, while the PAH-RHD gene sequences of Gram-positive bacteria (PAH-RHD[GP]) at sampling site A1 showed high sequence similarity to the nidA gene from Mycobacterium species. Meanwhile, molecular diversity of the two functional genes was higher at the upstream of this region, while lower at the downstream. Redundancy analysis indicated that environmental factors, such as NH₄--N, ∑PAHs, pH, SiO₃--Si, and water depth, affected the distribution of the PAH-RHD[GN] gene in the Pearl River estuary.

Spatial variation of bacterial community structure of the Northern South China Sea in relation to water chemistry

Spatial distribution, diversity and composition of bacterial communities of the northern South China Sea (SCS) surface water and the relationship with the in situ environmental chemistry were investigated. Polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) was used to investigate the bacterial community structure. The DGGE gel showed that each sample harbored a distinct bacterial community structure and spatial variations of bacterial community composition among all samples were obviously. A total of 17 intensive bands were excised and the sequence analysis of these DGGE bands revealed that Proteobacteria were the dominant bacterial group of surface water in the north part of SCS. Results of the taxonomic analysis showed that the communities consisted of Proteobacteria (α-subdivision, β-subdivision, γ-subdivision), Actinobacteria, Cyanobacteria, Bacteroidetes and Firmicutes. Unweighted pair group method with arithmetic averages clustering of the sampling stations indicated that all stations were classified mainly based on geographical proximity. Canonical correspondence analysis (CCA) was employed to further investigate the relationships between DGGE band pattern and the environmental variables and the first two CCA ordination axes suggested that the structure of the bacterial community was significantly correlated with the variables of nitrate (F = 1.24, P < 0.05).

Molecular Characterization and Expression Pattern of Gene IGFBP-5 in the Cashmere Goat (Capra hircus)

Insulin-like growth factor-binding protein-5 (IGFBP-5) is one of the six members of IGFBP family, important for cell growth, apoptosis and other IGF-stimulated signaling pathways. In order to explore the significance of IGFBP-5 in cells of the Inner Mongolian Cashmere goat (Capra hircus), IGFBP-5 gene complementary DNA (cDNA) was amplified by reverse transcription polymerase chain reaction (RT-PCR) from the animal’s fetal fibroblasts and tissue-specific expression analysis was performed by semi-quantitative RT-PCR. The gene is 816 base pairs (bp) in length and includes the complete open reading frame, encoding 271 amino acids (GenBank accession number JF720883). The full cDNA nucleotide sequence has a 99% identity with sheep, 98% with cattle and 95% with human. The amino acids sequence shares identity with 99%, 99% and 99%, respectively. The bioinformatics analysis showed that IGFBP-5 has an insulin growth factor-binding protein homologues (IB) domain and a thyroglobulin type-1 (TY) domain, four protein kinase C phosphorylation sites, five casein kinase II phosphorylation sites, three prenyl group binding sites (CaaX box). The IGFBP-5 gene was expressed in all the tested tissues including testis, brain, liver, lung, mammary gland, spleen, and kidney, suggesting that IGFBP-5 plays an important role in goat cells.

Position effect variegation and epigenetic modification of a transgene in a pig model

Sequences proximal to transgene integration sites are able to regulate transgene expression, resulting in complex position effect variegation. Position effect variegation can cause differences in epigenetic modifications, such as DNA methylation and histone acetylation. However, it is not known which factor, position effect or epigenetic modification, plays a more important role in the regulation of transgene expression. We analyzed transgene expression patterns and epigenetic modifications of transgenic pigs expressing green fluorescent protein, driven by the cytomegalovirus (CMV) promoter. DNA hypermethylation and loss of acetylation of specific histone H3 and H4 lysines, except H4K16 acetylation in the CMV promoter, were consistent with a low level of transgene expression. Moreover, the degree of DNA methylation and histone H3/H4 acetylation in the promoter region depended on the integration site; consequently, position effect variegation caused variations in epigenetic modifications. The transgenic pig fibroblast cell lines were treated with DNA methyltransferase inhibitor 5-Aza-2'-deoxycytidine and/or histone deacetylase inhibitor trichostatin A. Transgene expression was promoted by reversing the DNA hypermethylation and histone hypoacetylation status. The differences in DNA methylation and histone acetylation in the CMV promoter region in these cell lines were not significant; however, significant differences in transgene expression were detected, demonstrating that variegation of transgene expression is affected by the integration site. We conclude that in this pig model, position effect variegation affects transgene expression.

Transgene insertion affects transcription and epigenetic modification of flanking host sequence in transgenic pigs

Transgenic technology has been used for years to study gene function, produce important proteins, and generate models for the study of human diseases. However, the efficiency of producing transgenic animal lines that retain normal function is extremely low. The low efficiency can be mainly attributed to the integrated transgene. A further understanding of the effects of transgene integration on transcription and epigenetic modification of the host genome would improve the transgenic efficiency. Therefore, we utilized three transgenic pigs produced by SCNT expressing GFP, to identify alterations of transcription, DNA methylation and histone acetylation resulting from integration of the GFP gene. Multiple copies of the transgene integrated into a single site of the three transgenic pigs were verified by TAIL&mdash;PCR and the integration sites were different in each pig. We observed that the integrated transgene frequently resulted in significantly low transcription of flanking sequences in various tissues of transgenic pigs in comparison with wild&mdash;type pigs. Corresponding with the low transcription, DNA hypermethylation and loss of acetylation of histone H3 and H4 were detected. Our results demonstrate that the abnormal transcription and epigenetic modification of sequences flanking the transgene were not correlated with the expression of the transgene. However, the disturbance caused by the insertion of the transgene, was dependent upon the integration site. This suggests that some sequences in the host genome could permit integration and expression of transgene without causing defects in the host.

Identification of coastal water quality by statistical analysis methods in Daya Bay, South China Sea

In this paper, cluster analysis (CA), principal component analysis (PCA) and the fuzzy logic approach were employed to evaluate the trophic status of water quality for 12 monitoring stations in Daya Bay in 2003. CA grouped the four seasons into four groups (winter, spring, summer and autumn) and the sampling sites into two groups (cluster DA: S1, S2, S4-S7, S9 and S12 and cluster DB: S3, S8, S10 and S11). PCA identified the temporal and spatial characteristics of trophic status in Daya Bay. Cluster DB, with higher concentrations of TP and DIN, is located in the western and northern parts of Daya Bay. Cluster DA, with the low Secchi, is located in the southern and eastern parts of Daya Bay. The fuzzy logic approach revealed more information about the temporal and spatial patterns of the trophic status of water quality. Chlorophyll a, TP and Secchi may be major factors for deteriorating water quality.

Analysis of phenanthrene biodegradation by using FTIR, UV and GC-MS

The aim of this paper is to assess the biodegradation of phenanthrene by Flavobacteria FCN2 which was isolated from coke plant sludge via a classical shaken liquid medium enrichment method. The strain FCN2 can decompose phenanthrene (50 mg l(-1)) completely within 5 days. The values of pH decrease to 6.7 from 7.2 during degradation periods. And a detailed phenanthrene metabolism was assayed by using FTIR, UV and GC-MS. For FTIR, appearance of new broad absorption bands at 2858 cm(-1), 2927 cm(-1), 2955 cm(-1) and another new strong absorption band at 1734 cm(-1) in metabolites demonstrates that carboxyl group produced during phenanthrene degradation. Besides this, a very strong absorption band appears at 1260 cm(-1). It is ascribed to C-C stretching vibration band in carbonyl group of arone. Two weak adsorption at 334 nm and 349 nm in UV spectra were assigned to the n-pi* transition of CO of aldehyde. Two metabolites, phenanthrene-dihydrodiol and naphthalene-1-diol were identified in neutral fraction of phenanthrene degradation by using GC-MS. As a result carboxylic acids and arone were generated during biodegradation of phenanthrene by Flavobacteria FCN2.

Identification of anthropogenic effects and seasonality on water quality in Daya Bay, South China Sea

Thirteen water quality parameters from 12 monitoring stations were collected to study the effects caused by climate and anthropogenic activities on water quality in 2003 in Daya Bay, South China Sea. The data matrix has been built according to the results, which were analyzed by fuzzy c-mean cluster (FCM) and cluster analysis (CA). This analysis has identified anthropogenic effects and seasonal characters of water quality. The dry and wet seasonality have been demonstrated with FCM and CA. The precipitation and the Southeast Asian monsoons, northeasterly from October to the next April and southwesterly from May to September have also an important influence on water quality in Daya Bay. In the spatial pattern, two groups have been classified with FCM and CA. Cluster I consisted of the sites S3, S8, S10 and S11 in the west and north coastal parts of Daya Bay. Cluster I is mainly related to anthropogenic activities such as fish-farming. Cluster II consisted of the rest of the stations in the center, east and south parts of Daya Bay. Cluster II is mainly related to seawater input from South China Sea. Thus, fuzzy c-mean cluster and cluster analysis can be an important tool for the successful characterization of regional-scale water quality.

Search for a light pseudoscalar particle in the decay K_{L};{0}-->pi;{0}pi;{0}X

We performed a search for a light pseudoscalar particle X in the decay K_{L};{0}-->pi;{0}pi;{0}X, X-->gammagamma with the E391a detector at KEK. Such a particle with a mass of 214.3 MeV/c;{2} was suggested by the HyperCP experiment. We found no evidence for X and set an upper limit on the product branching ratio for K_{L};{0}-->pi;{0}pi;{0}X, X-->gammagamma of 2.4x10;{-7} at the 90% confidence level. Upper limits on the branching ratios in the mass region of X from 194.3 to 219.3 MeV/c;{2} are also presented.

Search for the Decay K L0-->pi0nu nu[over]

We performed a search for the K L0-->pi0nu nu[over] decay at the KEK 12-GeV proton synchrotron. No candidate events were observed. An upper limit on the branching ratio for the decay was set to be 6.7 x 10(-8) at the 90% confidence level.

Free fatty acids act as endogenous ionophores, resulting in Na+ and Ca2+ influx and myocyte apoptosis

AIMS

Disturbances in lipid metabolism have been suggested to play an important role in myocardial damage. Marked accumulation of free fatty acids (FFAs), including arachidonic acid (AA), palmitic acid, oleic acid, and linoleic acid, occurs during post-ischaemia and reperfusion (post-I/R). Possible cellular mechanisms of AA/FFAs-induced myocyte apoptosis were investigated.

METHODS AND RESULTS

In neonatal rat ventricular myocytes, AA/FFAs activate a novel non-selective cation conductance (NSCC), resulting in both intracellular Ca(2+) and Na(+) overload. AA caused sustained cytosolic [Na(+)](cyt) and [Ca(2+)](cyt) overload, resulting in mitochondrial [Na(+)](m) and [Ca(2+)](m) overload, which induced caspase-3-mediated apoptosis. Similar apoptotic effects were seen using Na(+) ionophore cocktail/Ca(2+)-free medium, which induced [Na(+)](cyt) and [Na(+)](m), but not [Ca(2+)](cyt) and [Ca(2+)](m) overload. Electron microscopy showed that inhibition of [Na(+)](m) overload prevented disruption of the mitochondrial membrane, showing that [Na(+)](m) overload is an important upstream signal in AA- and FFA-induced myocyte apoptosis.

CONCLUSION

AA and FFAs, which accumulate in the myocardium during post-I/R, may therefore act as naturally occurring endogenous ionophores and contribute to the myocyte death seen during post-I/R.

Arachidonic acid induces both Na+ and Ca2+ entry resulting in apoptosis

Marked accumulation of arachidonic acid (AA) and intracellular Ca2+ and Na+ overloads are seen during brain ischemia. In this study, we show that, in neurons, AA induces cytosolic Na+ ([Na+](cyt)) and Ca2+ ([Ca2+](cyt)) overload via a non-selective cation conductance (NSCC), resulting in mitochondrial [Na+](m) and [Ca2+](m) overload. Another two types of free fatty acids, including oleic acid and eicosapentaenoic acid, induced a smaller increase in the [Ca2+](i) and [Na+](i). RU360, a selective inhibitor of the mitochondrial Ca2+ uniporter, inhibited the AA-induced [Ca2+](m) and [Na+](m) overload, but not the [Ca2+](cyt) and [Na+](cyt) overload. The [Na+](m) overload was also markedly inhibited by either Ca2+-free medium or CGP3715, a selective inhibitor of the mitochondrial Na+(cyt)-Ca2+(m) exchanger. Moreover, RU360, Ca2+-free medium, Na+-free medium, or cyclosporin A (CsA) largely prevented AA-induced opening of the mitochondrial permeability transition pore, cytochrome c release, and caspase 3-dependent neuronal apoptosis. Importantly, Na+-ionophore/Ca2+-free medium, which induced [Na+](m) overload, but not [Ca2+](m) overload, also caused cyclosporin A-sensitive mitochondrial permeability transition pore opening, resulting in caspase 3-dependent apoptosis, indicating that [Na+](m) overload per se induced apoptosis. Our results therefore suggest that AA-induced [Na+](m) overload, acting via activation of the NSCC, is an important upstream signal in the mitochondrial-mediated apoptotic pathway. The NSCC may therefore act as a potential neuronal death pore which is activated by AA accumulation under pathological conditions.

Are the local blood oxygen level-dependent (BOLD) signals caused by neural stimulation response dependent on global BOLD signals induced by hypercapnia in the functional MR imaging experiment? Experiments of long-duration hypercapnia and multilevel carbon dioxide concentration

BACKGROUND AND PURPOSE

The relationship between the local blood oxygen level-dependent (BOLD) signals caused by neural stimulation (fBOLD) and the global BOLD signals induced by hypercapnia (hBOLD) has not been fully investigated. In this study, we examine whether fBOLD is modulated by hBOLD signals, by means of experiments using a relatively wide range of inhaled carbon dioxide (CO(2)) for a long duration of 5 minutes.

MATERIALS AND METHODS

Ten healthy volunteers were recruited, each undergoing 6 separate experiments by inhaling gas mixtures with different fractions of CO(2) (room air, 3%-7%). Each experiment contained 3 phases, prehypercapnic, hypercapnic, and posthypercapnic, during which boxcar visual stimulus was given. The local fBOLD signals were measured from areas showing activation patterns highly correlated with the visual stimulus paradigm, whereas the global hBOLD signals were measured from areas showing no visual activations. Percentage changes in fBOLD during transient-state hypercapnia and steady-state hypercapnia were both investigated in response to varying degrees of hypercapnic perturbations.

RESULTS

The hBOLD signals increased with increase of inhaled CO(2) fractions. The duration for the hBOLD signals to reach steady state prolonged with increase of inhaled CO(2) fractions. Normalized fBOLD ratio was inversely related to the inhaled CO(2) during steady-state hypercapnia but showed positive association with hBOLD during transient-state hypercapnia.

CONCLUSION

Our study concludes that the steady-state fBOLD signal intensity is dependent on and inversely related to the hBOLD signals. Previous reports documenting independent and additive relationships between hBOLD and fBOLD may likely be due to transient-state observations.

Multinucleated stromal giant cells in colonic lamina propria

AIMS

Multinucleated stromal giant cells occur in the anus, genitals and many other organs. They resemble myofibroblasts, react to local injury and are found incidentally or in association with various lesions. They have only rarely been reported to occur in the colon. The aim was to firmly establish their existence in colorectal lamina propria.

METHODS AND RESULTS

Specimens from one hundred biopsies taken from throughout the colon (70%) and rectum (30%) were retrospectively reviewed. Multinucleated stromal giant cells occurred in 23 specimens (23%), were pancolonic but surprisingly spared rectal mucosa (0%). Multinucleated stromal giant cells occurred in both normal mucosa and abnormal mucosa and appeared to be larger and more numerous in abnormal mucosa than in normal mucosa. Specimens with tubular adenomas appeared to have strikingly abundant multinucleated stromal giant cells with large numbers of nuclei. Immunohistochemistry and ultrastructural examination showed features consistent with myofibroblastic differentiation.

CONCLUSIONS

We have firmly established the existence of multinucleated stromal giant cells in colonic lamina propria and confirm their myofibroblastic differentiation. They may be more common in abnormal mucosa and particularly prominent in the setting of tubular adenoma. Absence of rectal multinucleated stromal giant cells may represent a microanatomical difference between the colon and rectum.

Mitochondrial Na+ overload is caused by oxidative stress and leads to activation of the caspase 3- dependent apoptotic machinery

Oxidative stress is one of the major causes of cell death. Using time-lapse confocal recording of live cardiomyocytes, we showed that H2O2 (OH*) caused a marked increase in Na+ and Ca2+ levels in both the cytosol ([Na]cyt, [Ca]cyt) and mitochondria ([Na]m, [Ca]m). The H2O2-induced intracellular Na+ ([Na]i) overload contributed to the H2O2-induced [Ca]cyt/[Ca]m overload via activation of the reverse mode of the Na-Ca exchanger. When myocytes were treated for 40 min with 100 microM H2O2 in normal medium, then returned to H2O2-free medium, the percentage of apoptotic cells increased from 4% at 0 h to 55 and 85% at 4.5 and 16 h, respectively. H2O2-induced apoptosis was completely prevented by using Na-free, but not Ca-free, medium. When a Na+ ionophore cocktail in Ca-free medium was used instead of H2O2 to increase the [Na]i by more than 30 mM without any change in the [Ca]i, cytochrome c release and caspase 3-dependent apoptosis occurred, showing that [Na]i overload per se induced apoptosis. We also showed that the increase in the mitochondrial, but not the cytosolic, Na+ levels resulted in the opening of the permeation transition pore, followed by cytochrome c release. Our findings therefore suggest that H2O2-induced [Na]m overload is an important upstream signal for the apoptotic machinery, and the prevention of [Na]m overload thus represents a particularly attractive target for strategies aimed at preventing oxidative stress-induced cell death.

Cholestatic hepatitis caused by acute gold potassium cyanide poisoning

INTRODUCTION

Poisoning after oral ingestion of gold potassium cyanide is rarely reported. A case of suicidal ingestion of gold potassium cyanide (potassium dicyanoaurate; CAS# 13967-50-5) is described.

CASE REPORT

A 27-year-old man attempted suicide by ingesting 5 mL gold potassium cyanide solution. He developed vomiting, hyperamylasemia, and hepatic dysfunction. Cyanide poisoning was not detected but acute gold toxicity was noted. Pathologic findings of the liver showed centrilobular cholestasis with eosinophilic degeneration. The whole blood and serum gold were 4361 and 6011 microg/L, respectively, and the 24-hour urine gold was 429 microg/d in samples obtained on day 4.

CONCLUSION

Gold-induced hepatotoxicity has been seen infrequently in patients receiving gold therapy. Reported agents include sodium aurothiomalate, sodium aurothiopropranol sulfonate, aurothioglucose, aurothiopolypeptide (Auro-detoxin), auric sulfide, and gold thiosulfate, our report adds gold potassium cyanide.

Acute ethylene chlorohydrin poisoning: experience of a poison control center

BACKGROUND

Ethylene chlorohydrin (CAS 107-07-3), a chemical once used in hastening grape vine sprouting in Taiwan, has caused severe toxicity upon acute exposure. Although such use of ethylene chlorohydrin is now prohibited in Taiwan, poisoning still occurs following its illegal use. Since data concerning human ethylene chlorohydrin poisoning remain rare, we report our experience in treating acute ethylene chlorohydrin-poisoned patients.

METHODS

A retrospective analysis was conducted to evaluate patients with ethylene chlorohydrin poisoning reported to Taiwan Poison Control Center during 1985-1998.

RESULTS

Seventeen patients with ethylene chlorohydrin poisoning were identified. There were 11 male and 6 female patients, ranging in age from 2 to 70 years (median 53 years). The intent of exposure was suicide in 5, accident in 9, and occupational exposure in 3 patients. Oral ingestion was the most common route of exposure (14 patients). Seven out of the 17 patients died within 24 hours due to metabolic acidosis and respiratory failure. Ethanol therapy, used in 2 patients, had no apparent benefit. Moderate or mild poisoning was characterized by gastrointestinal effects only and an uneventful recovery.

CONCLUSIONS

Ethylene chlorohydrin can result in severe metabolic acidosis, respiratory failure, coma, and death after acute exposure.

Arachidonic acid-induced H+ and Ca2+ increases in both the cytoplasm and nucleoplasm of rat cerebellar granule cells

1. Arachidonic acid (AA) exerts multiple physiological and pathophysiological effects in the brain. By continuously measuring the intracellular pH (pH(i)) and Ca2+ levels ([Ca2+]i) in primary cultured rat cerebellar granule cells, we have found, for the first time, that 20 min treatment with 10 microM AA resulted in marked increases in Ca2+ and H+ levels in both the cytosol and nucleus. 2. A much higher concentration (40 mM) of another weak acid, propionic acid, was needed to induce a similar change in pH(i). The [Ca2+]i increase was probably caused by AA-induced activation of Ni2+-sensitive cationic channels, but did not involve NMDA channels or the Na+-Ca2+ exchanger. 3. AA-induced acidosis occurs by a different mechanism involving predominantly the passive diffusion of the un-ionized form of AA, rather than a protein carrier, as proposed by Kamp & Hamilton for fatty acids (FAs) in artificial phospholipid bilayers (the 'flip-flop' model). The following results, which are similar to those observed in lipid bilayers, support this conclusion: (1) FAs containing a -COOH group (AA, linoleic acid, alpha-linolenic acid, and docosahexaenoic acid) induced intracellular acidosis, whereas a FA with a -COOCH3 group (AA methyl ester) had little effect on pH(i), (2) a FA amine, tetradecylamine, induced intracellular alkalosis, and (3) the AA-/FA-induced pH(i) changes were reversed by bovine serum albumin. 4. Further evidence in support of a passive diffusion model, rather than a membrane protein carrier, is that: (1) there was a linear relationship between the initial rate of acid flux and the concentration of AA (2-100 microM), (2) acidosis was not inhibited by 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid, a potent inhibitor of the plasma membrane FA carrier protein, and (3) the involvement of most known H+-related membrane carriers and H+ conductance has been ruled out. 5. Since AA can be released under both physiological and pathophysiological conditions, the possible significance of the AA-evoked increases in H+ and Ca2+ in both the cytoplasm and nucleoplasm is discussed.

Identification and characterization of the three chitin-binding domains within the multidomain chitinase Chi92 from Aeromonas hydrophila JP101

The gene (chi92) encoding the extracellular chitinase of Aeromonas hydrophila JP101 has been cloned and expressed in Escherichia coli. The mature form of Chi92 is an 842-amino-acid (89.830-kDa) modular enzyme comprised of a family 18 catalytic domain, an unknown-function region (the A region), and three chitin-binding domains (ChBDs; Chi92-N, ChBD(CI), and ChBD(CII)). The C-terminally repeated ChBDs, ChBD(CI) and ChBD(CII), were grouped into family V of cellulose-binding domains on the basis of sequence homology. Chitin binding and enzyme activity studies with C-terminally truncated Chi92 derivatives lacking ChBDs demonstrated that the ChBDs are responsible for its adhesion to unprocessed and colloidal chitins. Further adsorption experiments with glutathione S-transferase (GST) fusion proteins (GST-CI and GST-CICII) demonstrated that a single ChBD (ChBD(CI)) could promote efficient chitin and cellulose binding. In contrast to the two C-terminal ChBDs, the Chi92-N domain is similar to ChiN of Serratia marcescens ChiA, which has been proposed to participate in chitin binding. A truncated derivative of Chi92 that contained only a catalytic domain and Chi92-N still exhibited insoluble-chitin-binding and hydrolytic activities. Thus, it appears that Chi92 contains Chi92-N as the third ChBD in addition to two ChBDs (ChBD(CI) and ChBD(CII)).

Peculiar artifacts mimicking carcinoma

Artifacts that mimic malignancy may lead to diagnostic difficulty and can cause serious consequences. We present 2 cases received in consultation which demonstrated peculiar artifacts that closely mimicked carcinoma. In case 1, contaminating products of conception were confused with squamous cell carcinoma. In case 2, artifactual signet ring cells induced by procedural trauma were suspicious for signet ring cell carcinoma. In both cases, clinical correlation failed to completely exclude carcinoma, and limited tissue prevented use of ancillary studies. Our final resolution of these artifacts required lengthy and detailed morphologic analysis.

Rhabdomyolysis: an unusual feature with mushroom poisoning

Rhabdomyolysis resulting from mushroom poisoning previously has been unreported in the literature. We present an outbreak of Russula subnigricans poisoning with rhabdomyolysis. The most severely ill patient presented with rhabdomyolysis, severe electrolyte disturbance (hyperkalemia, hypocalcemia), respiratory failure, acute renal failure, pulmonary edema, ventricular tachycardia, and circulatory shock. Mycotoxin may be the cause of rhabdomyolysis. In areas where mushroom gathering is common, mushroom poisoning should be included in the differential diagnosis of rhabdomyolysis.

Food poisoning due to methamidophos-contaminated vegetables

BACKGROUND

Organophosphate poisoning is well known for its characteristic symptoms and signs, but food poisoning caused by pesticide-contaminated food is seldom reported.

CASE REPORT

We report three incidents of food poisoning that resulted from exposure to the organophosphate insecticide methamidophos in vegetables. These outbreaks caused a cholinergic syndrome in 4 patients. The cholinergic overactivity led as to suspect organophosphate food poisoning. All patients recovered well following appropriate therapy. The clinical diagnosis of organophosphate poisoning was confirmed by reduced levels of erythrocytes and plasma cholinesterase and the presence of methamidophos in the vegetable leftovers. The implicated vegetables and levels of methamidophos were: Ipomoea batatas 255 ppm, Gynura bicolor 110 ppm, and red cabbage 26.3 ppm. Since methamidophos is normally applied to vegetables during planting, improper selection and/or overuse of pesticide or improper harvest times may explain the occurrence of these high residue levels of methamidophos.

A case of jellyfish sting

Jellyfish sting may result in a wide range of symptoms from common erythematous urticarial eruptions to the rare box-jelly induced acute respiratory failure. In Taiwan, with the increasing frequency of international travel, cases of jellyfish sting to foreigners are on the rise. We report a case of jellyfish sting with the rare presentation of painless contact dermatitis. A 38-y-o man accidentally stepped on a sea urchin with his right foot during scuba diving in a beach in Thailand. Traditional therapy with vinegar was applied on the lesion. However, when he returned to Taiwan, erythematous patches on the left thigh with linear radiations to the leg were discovered. The skin lesions had bizzare shapes and showed progressive change. No pain or numbness was noticed. Jellyfish stingwas suspected, topical medications were applied, and the patient recovered without complication. Jellyfish stings usually result in a painful erythematous eruption. In this case, though the lesion involved a large surface, there was no pain. Delayed diagnosis of jellyfish sting was due to the atypical presentation and the physician's unfamiliarity to the Thai jellyfish sting. Awareness to the wide spectrum of jellyfish sting symptoms should be promoted.